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Buccal cortical bone thickness for mini-implant placement
Abstract
The thickness of cortical bone is an important factor in mini-implant stability. In this study, we investigated the buccal cortical bone thickness of every interdental area as an aid in planning mini-implant placement.
From the cone-beam computed tomography scans of 30 dry skulls, 2-dimensional slices through every interdental area were generated. On these, cortical bone thickness was measured at 2, 4, and 6 mm from the alveolar crest. Intraclass correlation was used to determine intrarater reliability, and analysis of variance (ANOVA) was used to test for differences in cortical bone thickness.
Buccal cortical bone thickness was greater in the mandible than in the maxilla. Whereas this thickness increased with increasing distance from the alveolar crest in the mandible and in the maxillary anterior sextant, it behaved differently in the maxillary buccal sextants; it was thinnest at the 4-mm level.
Interdental buccal cortical bone thickness varies in the jaws. There appears to be a distinct pattern. Knowledge of this pattern and the mean values for thickness can aid in mini-implant site selection and preparation.
... In the literature, several patterns relating to the cortical bone thickness at the buccal site of the posterior maxilla have been described. Some researchers have concluded that moving apically, the cortical bone thickness decreases at a distance of 4 mm from the alveolar bone crest, and then increases again up to the 6 mm level [25], and the same pattern is indicated by Kim et al. [43], who found that the cortical bone is thickest closest to and farthest from the CEJ, and thinnest in the middle. On the other hand, according to Fayed et al. [28], the buccal cortical thickness of the maxilla increases from the CEJ to the 4 mm level, and then decreases again from the 4 mm level to the 6 mm level. ...
... The results of this study suggest that at the upper level of the attached gingiva region, the cortical bone is probably thicker than at the lower and middle levels. As the lower level that is utilized in the present study is about 1.5-2 mm above the alveolar crest level, this is in correspondence with the 2 mm level of Baumgaertel and Hans [25], while the upper level is in correspondence with the 6 mm level. Thus, the results of this study are in agreement with Baumgaertel and Hans [25]. ...
... As the lower level that is utilized in the present study is about 1.5-2 mm above the alveolar crest level, this is in correspondence with the 2 mm level of Baumgaertel and Hans [25], while the upper level is in correspondence with the 6 mm level. Thus, the results of this study are in agreement with Baumgaertel and Hans [25]. In the study conducted by Fayed et al. [28], the CEJ was utilized as the reference, and measurements were made at 2, 4 and 6 mm cuts in the CBCT images. ...
This research aims to investigate the optimal buccal site on the attached gingiva of the posterior maxilla for mini-implant placement for anchorage purposes in orthodontics. In 23 female patients, mini-implants were implemented between the roots of the first molar and second premolar, in the maxilla, for anchorage purposes. A CBCT was acquired for diagnostic purposes, and intraoral scanning was performed. Using the digital model that was the result of combining the DICOM and STL files, the cortical bone thickness and density, as well as the trabecular bone density, were measured on three axial bone slices corresponding to the three defined height levels (lower, middle, upper) on the attached gingiva, in the interradicular area. Pearson and eta correlation tests were performed in order to investigate possible correlations between height in the attached gingiva, and the corresponding cortical bone thickness and density, as well as the corresponding trabecular bone density. The correlations regarding the height level in the attached gingiva were medium for the cortical bone thickness, and weak for the cortical bone density, while a strong correlation was found between the cortical bone thickness and density. The upper level of the attached gingiva, between the second premolar and the first molar in the maxilla, is the optimal site for mini-implant placement, as the cortical bone thickness and density are probably greater than in the lower and middle level.
... 9 Anatomical factors affecting the stability of bone-screws are bone characteristics (bone density, bone depth and cortical bone thickness), soft tissue characteristics (mucosa vs attached gingiva, tissue thickness, mobility and proximity to the frenum), 2 and the proximity of specific anatomical structures (roots, nerves, vessels and sinus/nasal cavities). 10 Multiple sites have been used for bonescrew insertion: palatal bone 9,11 the palatal side of the maxillary alveolar process, 12 the mandibular retromolar area, 13 the infrazygomatic crest, 14 the maxillary and mandibular bucco alveolar cortical plate, 15 and the posterior palatal alveolar process. 9 Recently, the mandibular buccal shelf has been proposed as a suitable extra-alveolar bonescrew insertion site. ...
... Certain insertion sites show high successful rates even though the anatomy of the bone is changing among the individuals. 9,15,21 CBCT is considered as a reliable source for giving the accurate information about the anatomy of the bone. A good primary stability is achieved by having a good bone quality. ...
... 22 Due to the importance of cortical bone thickness and buccal shelf bone width many studies have used the CBCT to evaluate the anatomy of the bone and assess the important structures in this area when placing a bone screw. 9,15,21 The mandibular buccal shelf which is the extension of the external oblique ridge is considered as a good insertion site for the bone screw placement because of the good bone density present in this area. Chang et al reported high success rate for insertion of the bone screw at the buccal shelf area. ...
Background and objectives: The important factors for placing orthodontic bone screw in�clude thickness of the cortical bone, width of the buccal shelf bone, insertion depth of the screw and the proximity from the inferior alveolar nerve. This study aimed to anatomically assess the mandibular buccal shelf as the insertion site for orthodontic bone screw and determine any differences according to side and gender. Methods: The study included 20 adult patients (10 males, 10 females; average age, 20-40 years). The measurements were made on cone-beam computed tomography (CBCT) scans of these 20 untreated orthodontic patients. The measurements were taken at mesiobuccal root, distobuccal root of the first molar, mesiobuccal root and distobuccal root of the second molar. The cortical bone thickness was measured at the 4 sites. The buccal shelf bone width was measured 4, 6 and 8 mm below cemento-enamel junction at the 4 sites. The distance between the inferior alveolar nerve canal and the outer surface of the cortical bone at the same 4 sites was measured.Results: The cortical bone thickness showed the most thickness at the mesiobuccal root area of the first molar and least thickness at the distobuccal root area of the second molar. Regarding the buccal shelf width 4, 6 and 8 mm below cemento-enamel junction the thin�nest site was mesiobuccal root of first molar and the thickest site was distobuccal root of second molar. For the distance from nerve the mesiouccal root area of the first molar was the nearest and the mesiobuccal root area of the second molar was the furthest. No signifi�cant differences were found between the right and left sides of males and females. Conclusions: The mesiobuccal side of the mandibular second molar is considered as the most appropriate site for the bone screw placement in the buccal shelf area.
... ness and depth in this area. These studies aim to identify the ideal bone zone for safe and reliable TAD placement (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23). While the results of the studies have indicated that bone thickness increases distally from the first to the second molar (13,17,22), there is less consensus on depth measurements since some authors find that they increase (13,17,18), while others find the opposite results (22). ...
... Most studies used the CEJ as a reference point due to its high reproducibility (12)(13)(14)(15)(17)(18)(19)21,22), while some used the alveolar crest (11,16,20). The alveolar crest was excluded in this study due to its variability and susceptibility to bone loss. ...
Background:
The placement of Temporary Anchorage Devices (TADs) in the mandibular buccal shelf area is a common option for distalizing the lower arch. Therefore, the study of bone thickness and depth in this area is mandatory before planning TAD insertion. The aim of this study was to quantify the width and depth of the mandibular buccal shelf structure and examine its associations with sex, age, skeletal class and vertical pattern.
Material and methods:
A cross-sectional study was carried out on cone beam computed tomographies obtained from 91 patients. The bone thickness was evaluated in the mandibular buccal shelf area 5 and 8 mm apical to the cement-enamel junction (CEJ), and the bone depth was measured 4 mm buccal to the CEJ at the level of the distal root of the mandibular first molar and the mesial root of the mandibular second molar using the InVivoDental 6.0 software.
Results:
The depth and thickness of the bone increased in distal areas, and the thickness was greater at 8 mm. No differences were found between sex or skeletal class. Bone thickness decreased with age, and it was significantly lower in hyperdivergent patients.
Conclusions:
The thickness of the bone was higher in distal and deeper areas, and the depth was greater in distal areas. The hyperdivergent facial pattern and age were negatively associated with bone thickness.
... Bone thickness decreases as the distance from the occlusal plane increases. This was also reported by Liou et al [11] and Baumgaertel [12] in their studies. Liou et al [11]. ...
... Taking these into consideration, the best possible site for the bone screw insertion in the infra-zygomatic crest region is above the distobuccal root of the maxillary first molar, 10 to 14 mm above the occlusal plane of the first molar, inserted at an angle of 65° to 70° to the occlusal plane. As reported by Baumgaertel and Hans [12] , 6 mm or more can penetrate the maxillary sinus when inserted in the infra-zygomatic crest region. Whereas, in the present study we observe that an IZC screw of length 9 to 11 mm can be used without sinus penetration. ...
... Plaque collection around the neck may be reduced by maintaining a smooth, well-polished surface on the neck. Most implant failure due to periimplantitis often originates at the intersection of TAD with the mucosa [3][4][5][6]. ...
... CT scans and cone beam computed tomography (CBCT) may provide site-specific estimates of bone density. Implants may not work well with bone types D4 and D5, as has been speculated [4]. ...
Reaction to the force application is observed in the clinical scenarios as anchorage loss, which is the unwanted movement of the teeth. A plethora of approaches have been developed over time in orthodontics to overcome anchorage loss. These approaches are termed anchorage reinforcement procedures. Anchorage loss refers to the unintended movement or shifting of teeth that are intended to remain stable and serve as anchoring points during orthodontic treatment. This loss of stability can occur in various dimensions, including horizontal, vertical, or transverse, and can result in undesired changes to the overall positioning and alignment of teeth. Anchorage can be termed as conventional intraoral anchorage which usually leads to significant anchorage loss. The conventional extraoral anchorage such as headgear suffers from the issue of compliance.
... Te current study results indicated that the lower facial cortical bone was larger than the upper. Also, the width tended to increase as far from the crest towards the apex; this fnding is inconsistent with the previous studies [21,22]. However, in the current study, the thickness of the buccal cortex of the mandible is higher than the maxillary which is in line with both Park and Cho and Farnsworth et al.'s fndings [23,24]. ...
... Several implant studies [22,37] have found that the density of available bone is one of the factors that infuence the primary stability of implants during placement. Tis information is valuable for surgeons operating in our community, considering modifying drilling procedures or implant choices. ...
Understanding the quality of the ridge and facial cortical bone in the aesthetic zone is important for treatment with an immediate dental implant. This study aimed to analyze bone density and widths of the facial cortical bone and alveolar ridge at the central incisors in relation to arch form. A total of 400 teeth from 100 cone-beam CT images were divided equally between the upper and lower central incisors. The central incisor area was assessed for the width of the facial cortical and alveolar bones at three different points (3 mm, 6 mm, and 9 mm from the cementoenamel junction). Arch forms and densities of cortical and cancellous bones in the interradicular regions were evaluated. The difference in facial cortical bone thickness at 3 points was smaller for the upper teeth than for the lower teeth on both sides. The alveolar bone width was higher in the maxilla than the mandible with highly significant differences ( P < 0.001 ). The highest bone density was at the buccal aspect of the mandible (897.36 ± 136.72 HU), while the lowest density was at the cancellous bone of the maxilla (600.37 ± 126.63 HU). The dominant arch form was ovoid 71%, followed by square 20% and the tapering arch form 10%. The tapering arch form has the highest alveolar bone width in the upper jaw without statistical significance. The facial cortical bone thickness needs to be evaluated before implantation in the anterior region because it is less than two millimeters in both jaws. CBCT is important for the immediate implant. The ovoid shape was the dominant arch form.
... there is a linear increase of cortical bone thickness from level 4mm to level 8mm from CEJ, This agrees with Alrbata et al., 2014 [19] but disagrees with Baumgaertel et al. who found that cortical bone thickness values were at the minimum in the middle and at the greatest in apical and coronal regions from CEJ [20,21] this may be the difference in the methodology used and sample selected and included in studies. Baumgaertel and Hans measured 30 dry skulls whereas Kim et al. measured cortical bone thickness on 23 Korean cadavers. ...
... In our study, the cortical buccal bone thickness was higher in the mandible than maxilla in most sites this agrees with (Baumgaertel, 2007) who measured the cortical bone thickness at 2, 4, and 6 mm from the alveolar crest and said that Buccal cortical bone thickness was greater in the mandible than in the maxilla [20] . ...
Background: This study aimed to evaluate the buccal cortical bone thickness of the Iraqi population for mini-implant insertion using cone-beam computed tomography (CBCT). Methods: This cross-sectional study was conducted on maxillary and mandibular CBCT scans of 40 patients (14-25 years). One examiner measured skeletal parameters at 4, 6 and 8 mm apical to the cementoenamel junction (CEJ). Results: the largest buccal cortical bone thickness in the maxilla was between the first and second molar (1.36mm for males, 1.24mm for females) and in the mandible was between the first and second molar (2.17mm for males, 2.37 for female). Conclusions: The buccal cortical bone thickness varies in different individuals. In the mandible, the buccal cortical bone thickness was increased as we move from the anterior to the posterior area. The buccal Cortical bone thickness is thicker in the mandible compared to the maxilla.
... The findings of the current study were in agreement with this, with significantly higher failure rates being observed in the mandible 28.2 compared to the maxilla 11.8 . Factors that may have contributed to these differences include variations in bone structure such as alveolar cortical bone thickness and mineral density [16][17][18] . Previous studies examining the alveolar bone structure in the molar regions of the maxilla and mandible reported thicker cortical bone 16,17 and higher mineral density 18 in the latter. ...
... Factors that may have contributed to these differences include variations in bone structure such as alveolar cortical bone thickness and mineral density [16][17][18] . Previous studies examining the alveolar bone structure in the molar regions of the maxilla and mandible reported thicker cortical bone 16,17 and higher mineral density 18 in the latter. However, further investigation of the association between TAD failure rates and cortical bone thickness and density is necessary in order to elucidate the mechanism of action. ...
Temporary anchorage devices （TADs） have become increasingly popular as orthodontic treatment measures for anchorage or distal movement of molars. However, TAD failure is a major limitation, and the aim of this study was to examine the effects of various factors on the timing of TAD failure. This study included 467 TADs implanted on the buccal side of the molar region in 197 patients undergoing orthodontic treatment. The relationship between failure and sex, age, jaw （maxilla or mandible）, side （left or right）, Frankfort mandibular plane angle （FMA）, point A-nasion-point B angle （ANB）, overbite, and overjet was examined. The time （number of days） until failure was also investigated. The failure rates were significantly higher in men compared to women （23.9％ vs. 13.6％; p-value＝0.024）, and in the mandible compared to the maxilla （28.2％ vs. 11.8％; p-value＜0.001）. A significant difference by age-group was also observed （p-value＜0.029）, with the failure rates being highest among patients aged ≥30 years （29.8％）. Approximately half （47.6％） of the maxillary failures occurred by day 120, and more than half （58.1％） of the mandibular failures occurred by day 60. Moreover, the failure rate by day 120 was higher in the maxilla when the FMA was smaller. The failure rates of TADs implanted on the buccal side of the molar region were influenced by sex, age, and location （i.e., mandible or maxilla）. Failure tended to occur more rapidly and readily in mandibular compared to maxillary implants. Moreover, when considering the vertical skeletal pattern, failure rates ＜120 days after implantation tended to increase when the FMA decreased.
... It is inherent that increasing the length of the MI will increase its stability, but in actuality, the manipulation of MI length is based on the thickness of the cortical plate at the site of placement. The thickness of the cortical plate affects the primary stability, 8,21 whereas the length of the MI is a subordinate factor, which explains why certain lengths are recommended for different anatomical sites. Cortical bone thickness varies at different aspects of placement. ...
... Cortical bone thickness varies at different aspects of placement. 21,22 Another point to consider when selecting the MI is the varying type and thickness of the soft tissue at the site. 23 It is important to remember that the increase in length does not increase the mechanical strength of the MI; it only efficiently augments the stability with the increase of contact with the cortical bone. ...
... In keeping with previous studies about placement site, the removal torque of the mandible was significantly higher than that of the maxilla due to the superior bone quality of the mandible [11,13,[15][16][17][22][23][24][25][26]. Hence, a heavier force can be loaded to the microimplants in the mandible if stabilized. ...
... The removal torques of the posterior teeth or retromolar areas were significantly higher than those of the anterior teeth area. This is likely attributed to the fact that the thickness and density of the cortical bone in the anterior teeth area are the lowest, and they can increase gradually toward the posterior area ( Table 2, Fig. 5) [24][25][26]. ...
Background
The current study aimed to evaluate factors affecting the long-term stability of microimplants using removal torque and the correlation between removal torque and clinical variables.
Materials and methods
This research evaluated 703 microimplants placed in 354 patients (mean age: 30.4 ± 12.1 years). The removal torque was evaluated according to various clinical variables including sex, age, placement site, microimplant size, and placement method (self-drilling versus pre-drilling). Pearson correlation and stepwise multiple linear regression analyses were performed to investigate different variables and their association with removal torque.
Results
The mean removal torque was significantly higher in the mandible (4.46 N cm) than in the maxilla (3.73 N cm). The values in the posterior teeth/retromolar areas were significantly higher than those in the anterior teeth area. There were no significant difference in terms of sex. Teenagers had a lower removal torque than older adults in the mandible, but not in the maxilla. Microimplants with a greater length and diameter, except for those with a greater diameter in the maxilla, was associated with a higher removal torque. Regardless of placement torque, the removal torque convergently reached approximately 4 N cm in both placement methods. The removal torque was significantly correlated with screw length in the self-drilling group and with diameter in the pre-drilling group.
Conclusions
Removal torque was related with placement site, age, placement method, and length and diameter of microimplants.
... The anatomical insertion of certain places appears to present trustworthy models and reproducible; yet, local anatomy is typically subject to significant individual differences. With the use of technology, information on the anatomical conditions of bones can be obtained 16 . Nucera et al.'s 17 focused exclusively on the analysis of hard tissues using CBCT for the anatomical features of the buccal shelf area on the body mandibular. ...
Objective: The aim was to determine the suitable sites of the mandibular buccal shelf (MBS) for the insertion of orthodontic mini-screws evaluating correlations between divergence and bone component and between divergence and inferior alveolar nerve (I.A.N.). Materials and Methods: The sample consisted of 93 Cone Beam Computed Tomography (CBCT). Hard tissues's study has analysed buccal total thickness, apico-coronal total bone depth and cortical coronal bone depth. The I.A.N.’s study analyzed height and buccal thickness and distance between I.A.N. and mini-screw. Results: Cortical depth at 4 mm and 6 mm showed significant measurements. The total thickness analysis at 6 mm didn't found difference while at 4 mm was significant for normodivergent in R7D and R7M. The bone height from I.A.N was higher in hyperdivergent at R7D and R6D. The thickness of the bone was significant in hypodivergents at L7D and R7M. The distance between I.A.N. and miniscrew was significant in L7M. Conclusions: The MBS offered adequate quantity and quality of bone for the insertion of mini-screws. The optimal site is the buccal bone at distal root of the second molar at 4 mm buccal to the cementoenamel junction (CEJ). The study showed no significant correlation between divergence and bone thickness. The bone height between the bone ridge and the roof of I.A.N. decreases progressively in the distal direction. Although hyperdivergent patients showed a greater height between the bone crest and I.A.N. in MBS, this variability isn’t clinically significant.
... According to Baumgaertal S, Hans MG, placing miniscrews in this region could penetrate the maxillary sinus. 6 According to Reiser et al., when the miniscrew extends less than 2mm into the maxillary sinus, the Schneiderian sinus membrane becomes elevated, favours blood clot formation and aids in healing.When the miniscrew extends more than 2mm into the sinus, it perforates the membrane and disrupts healing, increasing the incidence of sinusitis. 7 Previous studies show that variation in vertical facial dimension of the patients' has an impact on the maxillary sinus and the alveolar bonewidth. ...
: This research aimed to evaluate bone thickness and density using CBCT in the Mandibular Buccal Shelf (MBS) and the Infrazygomatic Crest (IZC) in individuals with varying vertical facial heights for optimal placement of miniscrews.
: The sample was made up of 90 people who were at least 16 years old. It was divided into three groups on the basis of vertical facial height which was assessed by lateral cephalometric analysis based on the Jaraback ratio, FMA, Y-axis and Mandibular plane angle. Cross-sectional CBCT slices of the MBS and IZC were obtained to evaluate bone thickness (horizontally and vertically) and density at 16 and 3 different sites, at 2 different angles, respectively.The normality of the data was statistically proven using the Kolmogorov-Smirnov test. ANOVA test was used to analyze the relation between bone thickness of the MBS and the IZC with different vertical facial heights.
Bone thickness and density in the MBS and IZC increased posteriorly. Higher bone thickness and density were found near the 2 molar in the MBS; in the IZC, it was higher between the 1 and 2 molar.
: Individuals with horizontal growth patterns had greater bone thickness in the MBS and IZC than Individuals with vertical growth patterns. The ideal location for installing miniscrews in MBS is buccal to the second molar's distal root, while in IZC it is above the proximal space between the first and second molars.
... mm and 1.12-1.22 mm, [22] respectively. This perforation of 6 mm would go 2-4 mm in the medullary bone. ...
Objective
The objective is to evaluate the effectiveness of two different penetration depths of micro-osteoperforations (MOPs) on the rate of orthodontic tooth movement over 60 days. In addition, the amount of pain and discomfort caused by the MOP was evaluated.
Materials and Methods
A total of 22 patients (18–30 years) who need fixed orthodontic treatment were recruited and randomly assigned into two groups. Randomization for determination of the experimental side and depth of perforations was done using sealed envelopes. On each patient, the other side of the mouth worked as control side with no MOPs. Patients in group 1 (MOP-5) received 3MOPs on the buccal surface of the alveolar bone each at 5 mm depth, whereas patients in group 2 (MOP-7) received 3MOPs on the buccal surface of the alveolar bone each at 7 mm depth. The amount of canine retraction was measured every 30 days at two intervals on both sides of the mouth. Pain perception was measured after 1 h, 24 h, 72 h, 7 days, and 28 days of procedure. MOP-related pain was measured using a visual analog scale. The level of statistical significance was P ≤ 0.05.
Results
The result of the intra-examiner reliability using intraclass correlation coefficient more than 0.97 ( P < 0.001), indicating excellent repeatability and reliability of the measurements. The baseline characteristics between groups were similar ( P > 0.05). Both the groups demonstrated a significantly higher canine movement than the control group. No significant difference was seen between the MOP-5 and MOP-7 groups ( P > 0.05) in terms of canine retraction. Mild-to-moderate pain was experienced only in the first 24 h of the procedure.
Conclusion
Three MOPs with a depth of 5 mm can be performed as an effective method to increase the rate of tooth movement. However, increasing the depth of perforation beyond 5 mm does not additionally enhance tooth movement.
... L'épaisseur optimale d'os cortical du côté palatin est située 8 à 10 mm apicalement au point de contact entre la 1 re et 2 e molaire et entre la 1 re molaire et la 2 e prémolaire. Il faut éviter une insertion plus apicale parce que l'os est plus mince et qu'il y a proximité avec le sinus [33,34]. La portion antérieure du palais située entre la 3 e et la 4 e rugosité palatine est considérée comme une zone sécuritaire avec une bonne épaisseur d'os cortical et une profondeur suffisante pour une vis de 8 à 10 mm [9, 35]. ...
Lorsque des mini-vis d’ancrage sont utilisées pour le traitement non invasif des béances antérieures, le clinicien doit tenir compte de la biomécanique du
système de forces utilisé. L’ingression des dents postérieures maxillaires et mandibulaires permet de maximiser les changements squelettiques verticaux.
En comparaison avec une chirurgie bimaxillaire, cette approche est moins invasive, moins compliquée et moins coûteuse.
... The primary stability of the miniscrews is an important factor for immediate loading during orthodontic treatment. Various insertion sites in the jaws have been used to achieve optimal primary stability [3]. The CBT plays an important role in the primary stability of a screw [4][5][6][7]. ...
Miniscrews are widely used in orthodontics as an anchorage device while aligning teeth. Shear stress in the miniscrew-bone interface is an important factor when the miniscrew makes contact with the bone. The objective of this study was to analyze the shear stress and force in the screw-bone interface for varying Cortical Bone Thickness (CBT) using Finite Element Analysis (FEA). Varying CBT of 1.09 mm (1.09CBT) and 2.66 mm (2.66CBT) with miniscrews of Ø1.2 mm, 10 mm length (T1), Ø1.2 mm, 6 mm length (T2) and Ø1.6 mm, 8 mm length (T3) were analyzed. Six Finite Element (FE) models were developed with cortical, cancellous bone, miniscrews and gingiva as a prism. A deflection of 0.1 mm was applied on the neck of the miniscrews at 0°, +30° and −30° angles. The shear stress and force in the screw-bone interface were assessed. The results showed that the CBT affects the shear stress and force in the screw-bone interface region in addition to the screw dimensions and deflection angulations. T1 screw generated lesser shear stress in 1.09CBT and 2.66CBT compared to T2 and T3 screws. Higher CBT is preferred for better primary stability in shear aspect. Clinically applied forces of 200 gms to 300 gms to an anchorage device induces shear stress in the miniscrew-bone interface region might cause stress shielding. Thus, clinicians need to consider the effect of varying CBT and the size of the miniscrews for the stability, reduced stress shielding and better anchorage during orthodontic treatment.
... Global research has shown that, evaluated and measured anatomical sites for safely and securely place of mini-screws in the inter-root distances of the maxillary and mandibular arches [8][9][10]. The inter-root distances have been assessed through the use of panoramic radiography, computed tomography (CT), and Cone-Beam Computed Tomography (CBCT) [11][12][13]. CBCT is the one of recent technological advantages in clinical dentistry and provides a detailed three-dimensional image of bones as well as accurate measurements of clinical parameters. To date, assessment of tooth inter-root distance has not been investigated in the Mongolian population. ...
Objectives: This study aimed to assess the mandibular and maxillary teeth inter-root distance using a Cone- Beam Computed Tomography (CBCT) image and determine the safe zone to insert mini-screws.
Methods: In this retrospective study, we included 100 subjects that were taken by CBCT in the Department of Orthodontics, School of Dentistry, Mongolian National University Medical Sciences (MNUMS) of Mongolia, from 2014-2021. We used CBCT images in the 100 subjects were obtained with using OnDemand3D software for linear measurements.
Results: The maxillary teeth inter-root distance was analyzed a total 100 (men 30, female 70) CBCT scans. There was no statistically significant difference between the genders. Maximum inter-root distance in maxilla were measured 7 mm above Cementoenamel Junction (CEJ) 1.89 mm between canine and I premolar teeth (p<0.05), 1.73 mm between I and II premolar (p>0.05), 1.79 mm between II premolar and I molar (p>0.05) and 1.59 mm between I and II molar (p<0.001), respectively. Maximum inter-root distance in mandible was measured 7 mm below CEJ, 2.51 mm between I and II premolar (p<0.001), 2.16 mm between II premolar and I molar (p<0.01) and 2.43 mm between I and II molar (p<0.01), respectively.
Conclusion: This suggests that the maxillary, mandibular molar teeth inter-root on the buccal side far from 7mm CEJ is considered to be the safest position to implant mini screws on cortical bone.
... The measurements show that the cortical layer is thicker the further from the alveolar crest and the more posterior the position is. The same discoveries can also be found in the literature (Baumgaertel and Hans, 2009;Cassetta et al., 2013). ...
Purpose: This study aims to measure the cortical and cancellous bone thickness in the upper and lower jaws, serving as a data template for developing pre-defined calcium phosphate cement primary implant forms. These measurements are crucial for creating a biphasic scaffold.
Methods: Forty complete jaws were assessed for cortical bone shape and thickness using statistical analysis and specific software tools. Sex and age were considered, and four groups were created.
Results: The cumulative thickness of the cortical layer varied from region to region. In both the upper and lower jaws, the cortical layer in the molar region was significantly thicker than in the frontal region. Within the alveolar process, cortical thickness increases with distance from the alveolar crest on both sides. The oral side of the lower jaw is significantly thicker than the vestibular side. For the upper jaw, no significant differences between the oral and vestibular sides were found in this study. Additionally, it is noteworthy that men have a significantly thicker cortical layer than women. Regarding age, no significant overall differences were found.
Conclusion: Mathematical analysis of anatomical forms using polynomial functions improves understanding of jaw anatomy. This approach facilitates the design of patient-specific scaffold structures, minimizing the need for costly and time-consuming planning and enabling more efficient implementation of optimal therapy.
... Various anatomical factors affect the stability of mini-screws, including bony characteristics such as density, depth, and critical bone thickness and soft tissue characteristics such as thickness, mobility, proximity to the frenum, and proximity to certain anatomical structures such as nerves, vessels, sinus/ nasal cavities, and roots. [5,6] Bone screw is another name for mini-implants that are placed in the extra-alveolar areas. ...
INTRODUCTION
The mandibular buccal shelf area is an extra-alveolar anchorage site that has high quality and quantity of bone, provides biomechanical benefits and has low failure rates. It is essential to place the implant in the region of bone with optimal thickness. The aim of this study was to determine the suitable site of the mandibular buccal shelf for bone screw insertion at 90 degrees and 30 degrees angles of insertion and various heights, angulations, areas of the buccal shelf in prognathic and retrognathic mandibles, and vertical and horizontal growth patterns.
METHODS
In this retrospective study, we evaluated the cone-beam computed tomography (CBCT) images of 48 patients in the age range of 18–30 years, divided into four groups. Seven sectional sites were examined at 3, 5, and 7 mm from the alveolar crest at 90 degrees and 30 degrees. The angulation and area of the buccal shelf were examined.
RESULTS
Cortical bone thickness increased distally from the first to the second molar in all four groups.
CONCLUSIONS
The preferred site for buccal shelf implant placement was distal to the mandibular second molar. The maximum amount of cortical bone was observed distal to the second molar, 7 mm vertically from the alveolar crest, when the buccal shelf implant was placed at 30 degrees angulation to the long axis of the tooth.
... mm [23] and 1.12-1.22 mm [24] , respectively. This perforation of 6 mm would go 3-3.5 mm in the medullary bone. ...
OBJECTIVE
To evaluate the effectiveness of micro-osteoperforation (MOP) over a 56-day period and to determine the influence of number of perforations on the rate of canine retraction. In addition, the amount of pain and discomfort caused by the MOP was evaluated.
TRIAL DESIGN
A single-center, split-mouth, triple-blind, randomized, controlled trial.
METHODS
22 patients (18–30 years) who need fixed orthodontic treatment were recruited and randomly assigned to MOP1 and MOP2 groups. The recruited patients were divided into two groups with 1:1 allocation ratio. Randomization for the determination of experimental side and number of perforations was done using sealed envelopes. On each patient, the other side of mouth worked as control side with no MOPs. 4 months after first premolar extraction, patients in MOP1 received 3MOPs on the buccal surface of alveolar bone, whereas patients in MOP2 received three buccal and three palatal MOPs in the experimental side. The amount of canine retraction was measured every 28 days at two intervals on both sides of mouth. Pain perception was measured after 1 hr, 24 hr, 72 hr, 7 days, and 28 days of procedure.
RESULTS
Result of the intra-examiner reliability using ICC is more than 0.97 (P < 0.001), indicating excellent repeatability and reliability of the measurements. The baseline characteristics between groups were similar (P > 0.05). A statistically significant difference in the rate of canine retraction on the MOP side was observed at the end of 56 days, amounting to two folds more than that of the control side. No significant difference was seen between MOP1 and MOP2 groups (P > 0.05). Mild-to-moderate pain was experienced only in first 72 hours of procedure.
CONCLUSION
The study recommends that MOP procedure has substantial potential to be used as an adjunct to the routine mechanotherapy for accelerating tooth movement, as it may reduce treatment time by half in the first four weeks after the MOP procedure.
TRIAL REGISTRATION
Clinical trial registry of India (CTRI/2022/12/048181).
... 20 This is may be related to the variations in bone structure such as mineral density and alveolar cortical bone thickness. 56,57 The optimal onset of force application has long been a disputed issue as to whether a healing period is necessary for mini-implants stability. Previous research reported immediate loading might destabilize implants and result in more failures. ...
Anchorage is a challenge and essential issue for an orthodontist in determining the success of orthodontic treatment. Orthodontic anchorage is defined as resistance to unwanted tooth movement. Mini-implant is one of the devices that can be used as an anchor in orthodontic treatment. Many cases have reported successful treatment using mini-implant, but there are cases where mini-implants may fail. Failure of mini-implants can affect orthodontic treatment, and it is known that several factors may lead to mini-implant loss in orthodontic treatment. This systematic review aimed to determine the factors influencing mini-implant failure in orthodontic treatment. Articles were selected from electronic databases (PubMed, Google Scholar, The Cochrane Library, ScienceDirect) from January 2015 until 2023 according to the PRISMA method ( Preferred Reporting Items for Systematic Reviews and Meta-Analysis ) under the PEOS (Population-Exposure-Outcome-StudyType) framework questions for systematic review. The study was registered in the International Prospective Register of Systematic Reviews (PROSPERO) database (CRD42022337684). All data collected were in English, and filtering was done by eliminating duplicate data, meta-analysis, case reports, case series, mini-reviews, and animal studies. The analysis was further divided into three groups, that is, patient-related, implant-related, and operator-related and operator-related (A graphical abstract provided as a Supplementary information [available in the online version]). Twenty-one articles were identified according to the inclusion criteria in the form of retrospective, prospective, in vivo , and randomized controlled trial studies. Mini-implant failures due to patient-related showed six etiological factors, failures due to implant-related had eight etiological factors, and only one factor was operator-related, which may lead to mini-implant failure. The data was extracted without a computerized system and only in English. Mini-implant failure can be caused by many factors; we could not accuse one major factor as a cause. However, the quality or condition of the bones and oral hygiene are factors that play a significant role in obtaining the stability of implants. Mini-implant failure is highly influenced by poor oral hygiene and peri-implant inflammation. Comprehensive diagnostic prior to mini-implant insertion should be appropriately considered. This systematic review describes several factors that can influence mini-implant failure, divided into three groups: patient-related, implant-related, and operator-related (A graphical abstract provided as a Supplementary information [available in the online version]).
... This could be attributed to the various local anatomical variations in the MBS region and the varying growth model of the individual, i.e., the vertical typology. Class III subjects are reported to have increased mandibular buccal bone thickness when compared to class I and II subjects [14]. A study by Ghosh et al. reported that MBS in the Indian population is mostly found to be thin and deep [15]. ...
Background
Computed tomographic evaluation of mandibular buccal shelf region in skeletal class III malocclusion cone beam computed tomography (CBCT) studies have been reported to have great alteration in the thickness of mandibular buccal shelf region owing to the different growth patterns and ethnic variations. The aim of this study was to determine the total and cortical bone thickness in the mandibular buccal shelf (MBS) region for extra-alveolar mini-screw placement in South Indian patients with sagittal skeletal class III malocclusion.
Material and methods
This retrospective computed tomographic study consisted of archived files of the Dravidian population with class III skeletal base that met the eligibility criteria. The total bone and cortical bone thickness of the buccal shelf regions were evaluated in relation to three anatomical sites at various depths and angulations. One-way ANOVA and Tukey honestly significant difference (HSD) post hoc tests were used for statistical analysis. Pearson correlation coefficient was performed to compare if any relation existed between bone thickness and the growth pattern.
Results
The maximum bone thickness in the buccal shelf region in our study was found at the distal portion of the second molar root, 8-12 mm from its cementoenamel junction (CEJ) and at 30-45 ° angulation (p-value<0.005). There was a positive correlation between the hypo-divergent growth pattern and the thickness of the bone.
Conclusion
Based on the sites recorded, the preferred site for mini screw placement in Class III patients is the distobuccal cusp region with respect to the second molar at a depth of 8-12 mm and at angulation of 30-45 °. There was a moderate correlation with hypo-divergent growth patterns, suggestive of a wider and thicker mandibular buccal shelf region in these subjects.
... Studies have shown thorough anatomical investigations that maxillary insertions pose the danger of causing oral-antral perforations when placing miniscrew implants. Such perforations should be avoided since they carry a number of dangers, including the possibility of infection (Baumgaertel and Hans, 2009;Baumgaertel, 2011). Other writers support focusing on the contralateral cortex and have shown improved primary stability with bicortical anchoring (Brettin et al, 2008). ...
Background and Objectives: TADs may be used in a variety of alveolar bone sites allowing for better orthodontic anchoring. The position of TADs is determined by the quality and quantity of bone. The aim of the present study is to anatomically assess the
anterior palate as the insertion site for orthodontic bone screw.
Method: This study was done by collecting three-dimensional data on the anterior palate for 40 patients with an age range of 20-30 years. The setting of the study was a private Maxillofacial Radiology Center in Erbil City. Measurements at 32 reference points and angulations were done with the help of a Radiologist to determine the ideal insertion point and angulation for TADs in the anterior palate.
Results: The thickness of the anterior palate differed significantly (p=0.00) among the 32 points studied, including 20 points at a zero angle to a vector perpendicular to the curve of the palate. The thickest point in the anterior palate was 6mm away from the midline at the contact point between canine and first premolar on both left and right sides, with means of 15.2 mm and 14.9 mm respectively, followed by 3mm away from the midline at the contact point between canine and first premolar on both left and right sides, with means of 14.4 mm and 14.9 mm respectively.
Conclusion: The thickness of the palatal hard tissue decreased from the anterior to the posterior.
Keywords: Anterior palate, CBCT, TADs, Miniscrew, Insertion Angle.
... Similar results were recorded by Abbas and Alhuwaizi [33] at the same levels. Baumgaertel and Hans [34] also recorded a thinner buccal bone in the upper jaw as compared to the lower jaw. ...
Background:
Implantology focuses on the measurement of bone thickness in both the lower and upper jaws. This study aimed to measure and compare alveolar bone thickness of the upper and lower jaws at single edentate sites and cortical bone thickness of their mesial and distal dentate sites.
Methods:
Thickness of alveolar bone thickness was measured in 80 upper and 80 lower implant edentate sites and that of buccal and lingual cortical plates of their mesial and distal dentate sites using Cone beam CT. The bone thickness of the edentulous sites was recorded at 3 points (crestal bone, five mm from the crest, and ten mm from the crest), while the bone thickness of the dentate sites was determined at four points (crestal bone, midroot bone, mid of the alveolar bone housing, and apical portion).
Results:
An increased amount of bone was measured from the crest to the apical portion of the dentate sites on the buccal and lingual sides of both jaws with a highly significant difference detected among all the tested points (P < 0.0001). No statistical difference was detected between the means of buccal bone width at the first 3 points, except at point 4 (the apical portion), where the mean of the lower jaw (3.35 ± 0.54) was significantly larger than that of the upper jaw (3.17 ± 0.55) (P = 0.04). Bone width measured in the edentulous sites showed a gradual increase from the crest to the apical portions in both jaws.
Conclusion:
Bone thickness at the coronal levels is low and susceptible to resorption compared to the apical portions regardless of the dentate state.
... More apical insertion should be avoided because of the thinner buccolingual bone and proximity to the sinus. 10,11 The anterior portion of the palate posterior to the third rugae is also considered a safe zone, with sufficient bone thickness and depth to support miniscrews. [12][13][14] We elected to use miniscrew anchorage to intrude the maxillary and mandibular segments, with comprehensive orthodontic treatment involving extraction of all four first premolars to help reduce the dentoalveolar protrusion and maximize the vertical effect. ...
Skeletal anchorage now provides a nonsurgical option for resolving a combination of open-bite malocclusion with vertical maxillary excess. Dr. Chamberland describes a double-arch molar intrusion method using palatal and buccal miniscrews. Two cases of nongrowing patients are presented to illustrate the technique.
... Bone thickness was found to decrease with an increase in distance from the occlusal plane in the present study, which is also shown in the study by Liou et al. 17 and Baumgaertel et al. 18 There was no significant difference in the bone thickness between gender which is in concordance with the study by Santos et al. 19 According to Al Amri et al., miniscrew insertion in IZC should be done cautiously because of the proximity to the maxillary sinus and nasal cavity. 20 The optimal site of miniscrew insertion found in the present study is at an angle of 70 , which is greater than the insertion angle of Taiwanese and Dravidian Indian population. ...
Introduction: The infrazygomatic crest (IZC) is an alternative site for miniscrew anchorage. It is important to analyze the anatomy of the region during preoperative planning to minimize the risk of unwanted tooth movement and injury to the vital structures. The literatures on the clinical application of miniscrew in IZC is scarce. Objective: To determine bone thickness, height and angle of insertion of miniscrew in the IZC region. Materials and methods: This cross-sectional observational comparative study included 44 patients above18 years. IZC bone thickness and height of miniscrew insertion were measured on cone-beam computed tomographic (CBCT) records. Student t-test was done to compare the bone thickness and insertion height between gender and between sides. Results: Infrazygomatic crest bone thickness when measured at an angle of 40° to 75° and 11 to 17 mm above the occlusal plane of the maxillary first molar was 3 to 9 mm. There was no significant gender and side variation in bone thickness of IZC and insertion height. Conclusion: Infrazygomatic crest thickness increases with the increase in insertion angle and the decrease in height. The optimal site for miniscrew placement in IZC in an adult is at the angle of 70°and 13 mm from the occlusal plane in the Nepali sample.
... Therefore it is important for a clinician to understand the bone density and varying cor-tical bone thickness throughout the maxilla and mandible. Anterior regions of the maxilla contain significantly higher proportions of cortical bone than the posterior maxilla, while the reverse is true in the mandible (4,5). As a general guideline, cortical bone thicknesses reach approximately 1.0-2.2mm in the anterior alveolar process of the maxilla and hard palate. ...
Background:
Knowledge of bone density in maxilla and mandible will allow the clinician to plan the anchorage strategies and placement of implants with necessary precautions. The study aims to evaluate the deflection changes of titanium alloy self-drilling mini implants from the intended path that occurs during placement in varying bone densities.
Material and methods:
63 titanium alloy self-drilling mini implants of the lengths 6mm, 8mm, and 10mm with diameter of 1.3mm were placed in three homogenous solid rigid polyurethane foam (saw bone) with bone densities of 20pcf, 30pcf, and 40pcf simulating anatomic sites in maxilla and mandible. 7mini implants of each length in all bone densities were tested for study. The implants were inserted perpendicularly into artificial bone block held in a custom made stand. The bone blocks were then radiographically exposed and the deviation of the long axis of the implantfrom a true vertical line was measured.
Results:
There was a decrease in deflection of the mini implant with increase in density. On the other hand, increase in length resulted in increase in the amount of deflection.
Conclusions:
Longer mini implants can be used in less dense bone as in maxilla, whereas shorter mini implants can be used in high dense bone as in mandible to increase the stability and success rate of implants. Bone density and implant length play a role in deflection of mini implant from its intended path of insertion. Key words:Orthodontic Mini implants, deflection, bone density, anchorage.
... Therefore, the positioning of the mini screw is largely based upon clinicians' experience. Improper positioning of the mini-screws in the alveolar bone could lead to damage to the teeth roots, inferior alveolar nerve, and perforation of the maxillary sinus [14][15][16]. ...
Objectives: This study aimed to assess mandibular and maxillary cortical bone thickness using a cone beam computer tomogram (CBCT) image to determine the safe zone to insert mini-screws. Methods: In this three factorial design study, we included 100 subjects divided into age group 1 (age 16-44 yrs.) and age group 2 (age 26-42 yrs.) that had taken a CBCT in the Department of Orthodontics, School of Dentistry, Mongolian National University Medical Sciences (MNUMS) from 2014-2021 We used CBCT images in the 100 subjects that were obtained with DENTRI (HDXWILL, Seoul, Korea) using OnDemand3D software for linear measurements. Results: The maxillary cortical bone thickness was heavier in the male gender at the premolar region level of 5 mm in age group I. Maximum maxillary cortical bone thickness as measured 7 mm from the Cemento-Enamel Junction (CEJ) between the 1st premolar and 2nd premolar was 0.99 mm, and the mandibular cortical bone thickness as measured 7 mm from the CEJ between the 1st molar and 2nd molar was 2.11 mm. Conclusion: This suggests that the maxillar and mandibular molar teeth cortical bone thickness on the buccal side of 7mm from the CEJ is considered to be the safest position to implant mini screws in cortical bone.
... According to Baumgaertel and Hans, mandibular bone is thicker than maxillary cortical bone. [7] At present, calipers and CBCT scans are used to measure the buccal bone thickness and compare variations according to gender, age, and tooth type. [8][9][10][11][12] During planning an endodontic surgery, 3D information of root configuration and jawbones obtained by CBCT imaging is desirable. ...
Aim: The aim of this study is to evaluate the distance from the buccal cortical bone surface to the root apex in the anterior mandibular teeth using cone-beam computed tomography (CBCT) and to correlate it to various associated factors (tooth type, gender, and age).
Materials and Methods: CBCT images of mandibular anterior teeth from 120 patient records with a sample size of 360 teeth were analyzed. The distance from the buccal bone surface to root apex and 3 mm above the root apex in the sagittal view was reconstructed using the Romexis software version 3.2.1.
Results: Distances from the buccal cortical bone surface to the apices of the root and 3 mm from the apex of the root were greater at the mandibular canine region than the central and lateral incisor (P < 0.001). The buccal bone was significantly thicker corresponding to the apices of the teeth compared to the region 3 mm from the apex (P < 0.001) The mean distance value from the cortical buccal bone surface to the lateral incisor apex (4.03 mm) was significant more among females (P = 0.006). Furthermore, the measured distance at the root apex and 3 mm above the of the root apex of the mandibular anterior roots were significantly more in patients below the age of 40 years (P < 0.05).
Conclusion: The distance from the buccal bone's surface to the apex and 3 mm from the apex in the mandibular anterior region is significantly affected by the tooth type and patients' age. CBCT is a reliable tool for presurgical evaluation for both these parameters during endodontic surgeries and implant placement.
... 17 Baumgaertel and Hans reported that an IZC screw of length 6 mm or more can penetrate the maxillary sinus. 18 Sinus penetration can also depend on other factors like anatomical variations in the sinus such as the reverse fold and prevalence of septa. 19 Another important factor deciding the primary stability of the screws is the cortical bone thickness. ...
Aim and Objective
The aim of the study was to compare the full-depth bone thickness and the cortical bone thickness in the infrazygomatic crest (IZC) region above the mesiobuccal (MB) root of maxillary first molar and second molar and thus find the ideal site for the placement of IZC screw.
Materials and Methods
Pretreatment cone-beam computed tomography images of 30 orthodontic patients were collected and IZC bone thickness and cortical bone thickness were measured above the MB root of maxillary first and second molar at an angle of 70° to the molar occlusal plane. Measurements were done on both right and left sides. Independent sample t test was done to compare the bone thickness between the right and left sides and also to compare the bone thickness above the first and the second molar.
Results
Mean bone thickness at the IZC region of 5.48 ± 2.2 mm and 7.78 ± 2.35 mm and a cortical bone thickness of 2.24 ± 0.46 mm and 2.13 ± 0.46 mm was obtained above the MB root of maxillary first molar and second molar, respectively. IZC bone thickness was significantly higher above the second molar than above the first molar ( P < .001), whereas there was no significant difference in the cortical bone thickness measured on both the sites ( P = .22).
Conclusion
Significantly higher IZC bone thickness was noted above the MB root of the maxillary second molar, which may ensure better stability and safety of the miniscrew.
... As studies have shown variances in bone patterns in various people, it is extremely crucial to pick a site for the installation of dental implants before the treatment and to thoroughly evaluate the oral anatomy and the width of both the ridge and the alveolar crest [11]. ...
Background:
Initial bone thickness has a substantial impact on the success of dental implant treatments. The objective of the current study was to analyze the thickness of the buccal and alveolar bone at the central incisors using CBCT in relation to gender and side to determine the anatomical features and choose the best implant treatment option for minimizing the surgical complications.
Methods:
One hundred CBCT images were investigated (50 females and 50 males, aged 20 to 50 years old). The buccal bone thickness and alveolar bone thickness were evaluated for right and left sides of each subject at three sites; C: crest (3 mm); M: middle (6 mm); A: apical (9 mm) from the cementoenamel junction.
Results:
The mean thickness of buccal bone was less than 2 mm on the incisors according to side and gender. Buccal bone thickness revealed a statistically significant difference between right and left sides at the apical point in both females and males with p values of (p ≤ 0.001) and (0.001), respectively. The buccal bone thickness displayed statistically significant differences between genders at all sites. The alveolar thickness demonstrated similar significant differences between genders except for the crest site.
Conclusions:
Iraqi participants had about 1 mm buccal bone thickness at 3 mm apical from the CEJ in right and left central incisors with a progressive rise in bone thickness to be less than 2 mm at the apex. Alveolar bone also showed the same increase in bone thickness from crest to apex. Bone thickness was greater in males than females. The present study provided valuable CBCT data on bone thickness of the esthetic maxillary region as a preoperative analysis for establishing an immediate implant treatment plan with aesthetically pleasing long-term outcomes.
... However, some outcomes are relatively predictable. [4][5][6] When planning for the design and placement of orthodontic mini-screws, the cortical bone thickness and bone width are 2 important micro-and macro-anatomical factors that should be considered. 7 Evaluation of distances at the mid-root level is also important in the treatment planning since it affects both the safety and stability of mini-screws. ...
Objective:
To determine the proper zones for placement of orthodontic mini-screws, based on cone-beam computed tomography (CBCT) measurements in the anterior mandibular region.
Methods:
The current cross-sectional study was performed on CBCT images of 77 individuals in the age range of 18-60 years. Axial slices at the levels of 2, 5, and 8 mm from the cementoenamel junction (CEJ) of the mandibular anterior teeth were selected. Interdental distances were measured in the mesiodistal direction, parallel to the midline of the mandibular arch. Areas with more suitable width were investigated for measuring the minimum interdental space. On the reconstructed cross-sectional images, labiolingual thickness of the bone was measured at the levels of 2, 5, 8, and 11 mm from the CEJ. The Kruskal-Wallis test, Mann-Whitney test with Bonferroni correction, Welch test, and Tukey's multiple analogy test were used to analyze the data.
Results:
Mesiodistal and labiolingual distances between the roots in every measured region had the highest values at the levels of 8 and 11 mm from the CEJ. The highest measured values were related to the interdental region between the lateral incisor and canine teeth on both sides of the arch. There were no statistically significant differences between these values (P < .001).
Conclusion:
The lateral incisor-canine areas at the level of 8 mm from the CEJ are introduced as the optimal sites for placement of orthodontic mini-screws. In addition, the results recommend the application of mini-screws with 1.3-1.7 mm diameter and 5-7 mm length.
... 2,9 Anchorage stability is related to whether there is sufficient bone quantity and density at the insertion site. 11 In the initial stages of SA placement, cortical bone thickness and density play important roles in primary stability, which is given by mechanical resistance during insertion. 12 Anatomically, the ZP of the maxilla, the IZC, and the MBS vary during the growth process, 3 so knowledge of possible age-related variations in length and thickness are very important for achieving proper SA stability and for avoiding tissue injuries and/or penetration of the maxillary sinus. ...
Introduction
The purpose of this study was to compare the thickness and length of the zygomatic process (ZP) of the maxilla, infrazygomatic crest area, and mandibular buccal shelf by sex and age.
Methods
Cone-beam computed tomography images of 128 subjects were divided into 3 groups: (1) 22 female and 19 male subjects aged 9-13 years, (2) 27 female and 20 male subjects aged 14-23 years, and (3) 20 female and 20 male subjects aged 24-50 years. A previously calibrated operator was used to take all measurements of the zygomatic process vertical bone thickness, zygomatic process horizontal bone length, zygomatic process/cementoenamel length (ZP/CEJL), infrazygomatic crest region bone thickness (IZCBT), infrazygomatic crest region bone length (IZCL), and mandibular buccal shelf bone thickness. Analysis of variance and Kruskal-Wallis tests were used for statistical analyses. Two-way analysis of variance was used for variables with significant differences by sex (P <0.002 as determined by Bonferroni correction for multiple comparisons).
Results
Differences by sex were only found for IZCL in the maxillary second premolar and first molar (U5-U6) and the maxillary first molar (U6). Significant differences were observed among age groups for ZP/CEJL, IZCBT in U5-U6 and U6, and IZCL in U6-distal.
Conclusions
The results suggest that ZP/CEJL and IZCL are larger in adults than in younger subjects, whereas IZCBT is smaller in adults than in younger subjects.
... 1 Factors that affect successful miniscrew placement are primary stability and distances to key anatomical structures such as dental roots and major blood vessels, among others. 2 To improve survival rates and obtain better biomechanical application vectors, orthodontists have examined the impact of placing intra-radicular screws both on the buccal and lingual sides of the alveolus, 3 and in the extra-alveolar positions at the retromolar area, with the hard palate either on the suture or lateral to it, 2,4 as well as in the infrazygomatic crest (IZC) 5 and mandibular buccal shelf (MBS). 6 Compared to intraradicular miniscrews, the latter two types allow to move the dentition with the application of an immediate and direct force to the dental arches without concerns of moving teeth against the miniscrews. ...
Objective:
To identify optimal areas for the insertion of extra-alveolar miniscrews into the infrazygomatic crest (IZC) and mandibular buccal shelf (MBS), using cone beam computed tomography (CBCT) imaging in patients with different craniofacial patterns.
Methods:
CBCT reconstructions of untreated individuals were used to evaluate the IZC and MBS areas. The participants were divided into three groups, based on the craniofacial pattern, namely, brachyfacial (n = 15; mean age, 23.3 years), mesofacial (n = 15; mean age, 19.24 years), and dolichofacial (n = 15; mean age, 17.79 years). In the IZC, the evaluated areas were at 11, 13, and 15 mm above the buccal cusp tips of the right and left first molars. In the MBS, the evaluated areas were at the projections of the first molars' distal roots and second molars' mesial and distal roots, at a 4- and 8-mm distance from the cementoenamel junction. Intergroup comparisons were performed with analysis of variance and the Tukey test.
Results:
There was no statistically significant difference in the IZC bone thickness among the groups. For MBS bone availability, some comparisons revealed no difference; meanwhile, other comparisons revealed increased MBS bone thickness in the brachyfacial (first molars distal roots) and dolichofacial (second molars mesial and distal roots) patterns.
Conclusions:
There was no significant difference in the IZC bone thickness among the groups. The facial skeletal pattern may affect the availability of ideal bone thickness for the insertion of extra-alveolar miniscrews in the MBS region; however, this variability is unlikely to be clinically meaningful.
Aim
To assess the height, thickness, and density of the infrazygomatic crest for extra-alveolar miniscrew insertion using cone beam computed tomography (CBCT).
Methods
Retrospective data from 65 CBCTs of Peruvian adults aged 20 to 38 years (mean age 27.37 years) with complete maxillary dentition were used in this study. Height (mm), thickness (mm), and density (Misch classification) were measured in the left hemimaxilla at the mesial and distal level of the upper first molar and the mesial of the second molar. Data on age and sex were collected. Intergroup comparisons were analyzed using the ANOVA or Kruskal–Wallis test.
Results
The heights from lowest to highest values were mesial second molar (10.39 ± 2.01 mm) < distal first molar (13.24 ± 1.44 mm) < mesial first molar (15.95 ± 2.06 mm) ( P < 0.001). The thickness was statistically greater in the mesial second molar (5.5 mm) than in the first molar (3.4 to 3.42 mm) ( P < 0.001). Density was similarly distributed between type 1 (50.8 to 56.9%) and 2 (43.1 to 49.2%) at the three levels of molar roots ( P > 0.05). Age and sex were not found to be statistically related to infrazygomatic crest height, thickness, or density at the three molar root levels ( P > 0.05).
Conclusion
Both the first and second molar infrazygomatic crest had adequate bone quality for extra-alveolar miniscrews placement, but the mesial of the second molar had the greatest thickness and a shorter distance from the occlusal plane, regardless of age and sex.
Os cistos periapicais são as lesões císticas odontogênicas mais comuns de origem inflamatória. Envolve tanto o osso maxilar quanto o mandibular, podendo atingir grandes proporções e áreas/estruturas adjacentes.O objetivo desse trabalho é relatar 03 casos de cistos periapicais de grande extensão em maxila submetidos a abordagem cirúrgica descompressiva. O caso 01 trata-se de um paciente do sexo masculino, 47 anos, com aumento de volume no palato duro com tempo de evolução de aproximadamente quatro meses. Ao exame tomográfico, observou-se uma área hipodensa de grande extensão envolvendo desde o dente 16 ao dente 22. Uma hipótese diagnóstica de cisto periapical foi elencada diante de resultado negativo no teste de sensibilidade dos dentes 15 a 22 e percussão vertical e palpação positivas. Como primeira conduta, optou-se por realizar marsupialização e remoção de fragmento para análise histopatológica. O caso 02 trata-se de uma paciente do sexo feminino, 35 anos, com aumento de volume significativo em região de palato duro do lado esquerdo com tempo de evolução de dois meses. Ao exame tomográfico, observou-se uma extensa área hipodensa envolvendo região dos dentes 21 a 23 já tratados endodonticamente. Uma hipótese diagnóstica de cisto periapical foi elencada. A conduta inicial envolveu tratamento descompressivo e um fragmento foi removido para confirmação de diagnóstico. E o caso 03 também trata se um aumento de volume também no palato duro do lado esquerdo associada a uma imagem hipodensa, via tomografia, envolvendo os dentes 21 a 24. Ao exame clínico, além do aumento de volume, observou teste de sensibilidade negativo para os dentes 21 e 22, além de percussão vertical e palpação positivas. Diante disso, uma hipótese diagnóstica de cisto periapical foi elencada e uma descompressão foi realizada, além de remoção de fragmento para confirmação histológica. Todos os 03 pacientes estão em acompanhamento, há em média 06 meses, aguardando regressão de lesão para planejamento de novas intervenções, como a enucleação completa, se necessário. Os pacientes também foram encaminhados para tratamento endodôntico dos dentes necessitados. Apesar dos pacientes ainda estarem em tratamento, foi possível observar os bons resultados de técnicas cirúrgicas descompressivas. Palavras-chaves: Radicular Cyst; Clinical Diagnosis; Endodontia.
A BSTRACT
Background
The continuous evolution in orthodontics introduces innovative materials and methods to enhance treatment efficacy. Among these advancements, orthodontic anchorage screws, particularly miniscrews, have revolutionized treatments by offering diverse nonsurgical solutions for managing space discrepancies and certain skeletal malocclusions. The success of miniscrews is influenced by various factors including patient-related factors (age, sex, skeletal pattern, and oral hygiene), miniscrew-related factors (diameter, length, shape), and treatment-related factors (technique, applied forces, and insertion site).
Materials and Methods
This study used Cone Beam Computed Tomography (CBCT) to evaluate the mandibular buccal shelf area for miniscrew placement across different sagittal and vertical skeletal patterns in 63 subjects, categorized based on the ANB angle and Jarabak ratio into Class I, II, III, and horizontal, average, and vertical growth patterns, respectively. Measurements were taken at specific sites related to the mandibular first and second molars, focusing on angulation, buccal bone depth (4mm and 6mm from the cementoenamel junction), and buccal bone thickness (6mm and 11mm from the cementoenamel junction).
Results
There were no significant statistical differences in any measurement between the right and left hemiarches. The values for the bone around the distal root of the mandibular second molar were significantly greater than the other values. With regard to Sagittal Skeletal Pattern, Class I cases showed greater values as compared to Class II and Class III with a significant difference in the angulation, bone depth, and thickness at 11 mm from CEJ. Although values tended to be greater in patients with horizontal growth pattern, the difference was not statistically significant.
Conclusion
Mandibular buccal shelf provides an optimal bone site for miniscrew insertion with better osseous characteristics at the distal root of the mandibular second molar. Subjects with skeletal Class I and horizontal growth pattern exhibit the most favorable osseous characteristics in the MBS area. However, in terms of bone thickness at 6 mm from CEJ Class III cases showed significant difference compared to Class I and Class II.
Background: The orthodontic management of pediatric patients with rare diseases, such as Ectodermal Dysplasia (ED) and Osteogenesis Imperfecta (OI), requires complex protocols due to dental anomalies in both the number and structure of teeth. These conditions necessitate a departure from traditional orthodontic approaches, as skeletal anchoring is often required because of these anomalies. Case Presentation: A patient with ED, characterized by hypodontia and malformed teeth, presented with insufficient natural teeth for anchorage. This challenge was addressed using a Maxillary Skeletal Expander (MSE) with miniscrews. Cone-beam computed tomography (CBCT) and cephalometric radiographs were used to assess bone density, which guided the creation of a customized hybrid device. A second patient with OI, a condition causing fragile bones, had malformed teeth and a high risk of fractures. Skeletal anchoring with MSE and miniscrews was chosen to avoid damaging brittle bones. The fragile nature of the patient’s bones required careful planning and close monitoring throughout the treatment process. Both patients were treated at the UOC of Pediatric Dentistry, Sapienza University of Rome, using MSE with miniscrews. Pre- and post-treatment imaging (CBCT and cephalometric radiographs) were used to evaluate bone quality and monitor progress. Skeletal anchoring successfully addressed the unique challenges in both cases, achieving outcomes comparable to those in unaffected patients. Discsussions: despite limited bone volume, MSE successfully achieved maxillary arch expansion and improved occlusion. Post-treatment radiographs showed successful maxillary expansion and alignment without complications. Conclusions: This case series highlighted the effectiveness of MSE with miniscrews in treating patients with rare diseases. It advances orthodontic management by offering reliable solutions for complex cases involving dental anomalies and compromised bone structures.
Background: This study was to assess the primary stability of orthodontic mini-screws of the same design produced by a conventional and a novel manufacturing method. Methods: A total of 150 orthodontic mini-screws with a body length of 8 mm, a diameter of 1.6 mm, a button head, and a self-drilling feature were used in the study. Mini-screws were manufactured through computer numerically controlled (CNC) and selective laser melting (SLM) manufacturing methods. Titanium (T) and stainless steel (SS) alloys were used as manufacturing materials. The study was conducted on three groups; CNC-T, SLM-T and SLM-SS. Mini-screws were placed at 60- and 90-degree angles in fresh bovine femur bones, where the cortical bone thickness was 2 mm. With the radiofrequency analysis (RFA) technique, the stability of the mini-screws was determined immediately after they were placed (F0), immediately after applying orthodontic force to the mini-screw (F1), after six hours (F6), and after 24 hours (F24). Three-way robust ANOVA was used to compare the data, and the Bonferroni correction was statistically applied. Results: Except for the insertion angle of the mini-screw, the group and time factors had statistically significant effects on the RFA values. The highest RFA value was detected in the SLM-T group. Conclusion: Orthodontic mini-screws manufactured from titanium or stainless steel alloys using the SLM technology can be an alternative to mini-screws manufactured using the traditional manufacturing method. The mini-screws manufactured using the SLM technology demonstrated adequate primary stability when subjected to an orthodontic force. Keywords: Orthodontic mini-screw, Primary stability, Selective laser melting, Computer numerical control, Radiofrequency analysis
Objectives
To determine the optimal sites of mini‐implant placement in the palatal alveolar cortical bone by using cone‐beam computed tomography (CBCT).
Subjects and Methods
CBCT records of 60 patients were divided into 2 groups of equal sizes, based on age and sex. The images were analyzed using Planmeca Romexis Software (Version 4.1.2). The measurements were made in axial sections of the maxilla and mandible, at 2mm, 4mm, and 6mm from the CEJ. The optimal sites were defined in terms of (a) Palatal or lingual alveolar cortical bone thickness and (b) Mesiodistal palatal or lingual inter radicular width.
Results
The optimal site for mini‐implant insertion, anteriorly, was the canine‐lateral incisor embrasure in both the jaws. Posteriorly, the inter‐molar embrasure in the mandible and the molar‐premolar embrasure in the maxilla were optimal sites. Females demonstrated significantly lesser bone widths in all areas of the maxilla (p<0.05) but greater bone thickness in the mandibular regions, as compared to males. The adolescent age group demonstrated a significantly lesser bone thickness but greater mesiodistal widths than the adult population in both the jaws (p < 0.05).
Conclusion
The optimal sites for mini‐implant insertion were the anterior canine‐lateral incisor and posterior buccal inter‐radicular embrasures, in both the jaws. Significant differences existed between age and gender groups, which need to be kept in mind while choosing the locations for placing mini‐implants.
1.1. Introduction: The purpose of this study is to compare dental and skeletal effects in Herbst appliance treatment without anchorage, with interradicular skeletal anchorage and with skeletal anchorage in the external oblique line. 1.2. Materials and Methods: forty-eight patients were selected and divided in 3 different anchorage groups. Control Group [CG], Interradicular Group [IRG] and External Oblique Line Group [EOLG]. Measurements were made using lateral craneal X-ray.
Aim The aim of this study will be to compare the amount of root resorption of maxillary anterior retracted with anterior TADs,regular TADs and without skeletal anchorage. Materials and methods: Samples for the study will be the patients undergone orthodontic treatment at the Department of Orthodontics,K.V.G. Dental College and Hospital, Sullia Sample size of 45 patients will be divided in to 3 groups . ,Group 1 consists of patients treated with anterior TADs, Group2 consists of patients treated with regular TADs and Group 3 consists of patients treated without skeletal anchorage for retraction of maxillary anteriors. Root resorption will be measured by comparing pretreatment and post treatment intraoral periapical radiographs (IOPAR) radiographs. Result- The study meticulously compared root resorption levels among three groups: Conventional, Anterior Temporary Anchorage Devices (TADs), and Posterior TADs. Anterior TADs exhibited the highest mean root resorption, significantly higher than both Conventional and Posterior TADs. Statistical analyses confirmed these differences, highlighting the impact of anchorage method on root resorption. Pairwise comparisons and confidence intervals further supported the findings, emphasizing the nuanced variations observed.
Introduction: Skeletal anchorage devices for the efficient orthodontic treatment mechanics can be placed at various interradicular and extraradicular sites intra orally. However, their placement in the infrazygomatic crest area can broaden the horizon of orthodontic treatment. The bone thickness in the infrazygomatic crest (IZC) area can vary at different heights and insertion angles during the placement of IZC screws between maxillary second premolar and second molar region.
Aims and objectives: The purpose of our study was to evaluate the variation in bone thickness in the IZC area at different insertion angles along the mesiobuccal root of maxillary first molar and at different heights from the crest of the alveolar bone in the apical direction between maxillary second premolar and second molar region using cone beam computed tomography, so as to determine the best possible site where the bone thickness will be maximum that will suit to a particular size of IZC screw.
Materials and Methods: CBCT images of 50 subjects were analyzed by a single observer, the bone thickness in the IZC area was measured and interpreted at different heights from the alveolar crest in the apical direction, that is, 5 mm, 7 mm, 9 mm, 11 mm at six regions between maxillary second premolar and second molar. Bone thickness was also measured at different insertion angles ranging from 55º to 75º to occlusal plane of permanent maxillary first molar along its mesiobuccal root.
Results: The bone thickness in the IZC area was 4.5 mm–3.5 mm, when it was measured at different angles ranging from 55º to 75º to the occlusal plane of maxillary first molar along its mesiobuccal root with maximum bone thickness at 75° with a mean ± SD of 4.56 ± 1.4. Statistically significant differences in bone thickness were found between maxillary first and second molar on both right and left sides at different heights with maximum bone thickness at 11 mm apical from the alveolar crest with a mean ± SD of 2.03 ± 0.76 and 1.91 ± 0.88, respectively, and along the mesial root of maxillary second molar on right and left sides at 11 mm apical from the alveolar crest with a mean ± SD of 2.12 ± 0.80 and 1.95 ± 0.75, respectively.
Conclusions: The best site and safe zone for miniscrew insertion in IZC area is at 7 mm to 9 mm distance from the alveolar crest apically along the mesial root of maxillary second molar and at an angle of 55°–75º to the occlusal plane of maxillary first molar, so as to ensure the adequate stability of the miniscrew and without causing any damage to the adjacent anatomical structures.
Application of orthodontic forces is concomitant with changes in the surrounding bone and periodontal ligament and consequential release of multitude of mediators in gingival crevicular fluid (GCF), saliva, and other body fluids at varied time points. Although the evidence of clinical tooth movement has progressed with the advent of newer three dimensional (3D) diagnostic aids, the evidence related to underlying cellular and molecular changes concomitant with release of biomarkers in the paracrine environment, is slowly and steadily evolving. The current lecture will highlight the importance of structured critical appraisal of evidence related to biomarkers in tooth movement to give valuable insights into the best orthodontic practices. These clinical implications may include but is not exhaustive of the magnitude and type of force, force re-activations, and growth status of the patients. The lecture also entails current research trends on bio-orthodontics by presenting a viewpoint on newer realms like microRNAs (miRNAs) in body fluids, which work as RNA-interfering systems or gene silencing entities, and may have significant impact on accelerating the tooth movement or in personalised patient care.
Introduction: Knowledge of the safe zone of mini-implant placement guides clinicians in choosing where to place mini-implants. Several studies evaluated the safe zone for mini-implants placement, but only a very few previous studies have taken different skeletal patterns into account when assessing measurements. Objective: The purpose of this cross-sectional, comparative study was to compare the inter-radicular distance and buccal cortical bone thickness in Class I and Class II skeletal malocclusion patterns. Materials and Methods: A total of 62 CBCT images of patients with Class I and Class II skeletal malocclusion were obtained from the records of the department of Oral medicine and Radiology, Kathmandu University Teaching Hospital. The inter-radicular distance and buccal cortical bone thickness were measured at four different heights (2, 4, 6 and 8 mm) from the CEJ towards the apex. These measurements were measured between different skeletal pattern and gender with independent t-test. The intergroup comparison at different height from CEJ was done with ANOVAfollowed by Tukey's post-hoc test to see the difference within the category. Result: There was a statistically significant difference observed in the inter-radicular distance between the maxillary first and second premolars at a height of 6 mm between Class I and Class II malocclusion patterns (p = 0.03). There were differences observed in the inter-radicular distance of the mandible at a different height based on skeletal malocclusion pattern, which was not statistically significant (p > 0.05). The buccal cortical bone thickness between the maxillary central and lateral incisors at the height of 2 mm from CEJ between Class I and Class II skeletal malocclusion patterns was statistically significant (p = 0.01). The buccal cortical bone thickness of the mandible at different heights based on skeletal malocclusion pattern there were differences observed which were not statistically significant (p > 0.05). Conclusion: The inter-radicular distance and buccal cortical bone thickness could be influenced by different skeletal patterns and tend to increase from the CEJ to the apex in both Class I and Class II skeletal patterns.
Background
The purpose of this study was to assess the sphericity of periapical lesions and its relation to the cone beam computed tomography periapical volume index (CBCTPAVI).
Methods
261 periapical lesions were assessed using cone beam computed tomography images from InteleViewerTM. Three-dimensional analysis of the lesions was conducted using analytical imaging software Mimics ResearchTM. Lesion volume and surface area measurements were determined using the semi-automatic segmentation technique and these measurements were then used to determine lesion sphericity and CBCTPAVI score. One-way analysis of variance with post-hoc Tuckey test was used to assess for differences in sphericity among CBCTPAVI groups.
Results
The mean sphericity of periapical lesions was 62%. Periapical lesions with larger CBCTPAVI scores were significantly less spherical than lesions with smaller CBCTPAVI scores.
Conclusions
Periapical lesions of endodontic origin are mostly semi-spherical in their spread and as CBCTPAVI score increases, sphericity decreases, indicating that larger lesions expand less uniformly compared with smaller lesions. Clinicians should be aware that lesions of increased volume, have less sphericity, and are thus elongated or stretched in one or more anatomical plane. This information will assist clinicians in planning and performing periapical surgery and may aid in differential diagnosis of radiolucent jaw lesions.
Bei der vorliegenden Arbeit handelt es sich um eine klinische und radiologische Nachuntersuchung von insgesamt 114 Patientinnen und Patienten, die zwischen 2009 und 2012 in der Poliklinik für Zahnerhaltung und Parodontologie der Universität Würzburg von approbierten Zahnärztinnen und Zahnärzten endodontisch behandelt wurden. Dabei kamen drei verschiedene Obturationsmethoden zum Einsatz. 1. Single-Cone-Technik mit Guttapercha und AH Plus® (SCGP) 2. Single-Cone-Technik mit Guttapercha und GuttaFlow® (SCGF) 3. Adhäsive Obturation in Continuous-Wave-Technik mit Resilon® (CWR) Die Erhebung der Ausgangsvariablen (zum Behandlungszeitpunkt) erfolgte retrospektiv unter Zuhilfenahme der klinischen und radiologischen Dokumentation. Die Reevaluation des periapikalen Zustands der Zähne und die Erhebung weiterer klinischer Parameter erfolgte im Rahmen eines aktiven Patientenrecalls nach durchschnittlich 6,3 Jahren. Dabei wurden mit möglichst hoher Standardisierung postoperative Einzelzahnaufnah-men angefertigt. Diese wurden anhand der PAI-Klassifikation ausgewertet, um den pe-riapikalen Zustand der Zähne vor und nach Therapie zu bestimmen. PAI-Werte von 1 und 2 galten als Behandlungserfolg, Grad 3 bis 5 als Misserfolg. Im Hinblick auf die de-finierten Arbeitshypothesen wurden die Erfolgsraten innerhalb der Kohorten miteinander verglichen. Das vorrangige Ziel der hier vorliegenden Arbeit war, zu untersuchen, ob der endodontische Behandlungserfolg abhängig von der jeweiligen Obturationsmethode ist und ob technikspezifische Unterschiede sich einerseits auf die Qualität der Obturation und andererseits auf das Auftreten möglicher Komplikationen, wie der periapikalen Extrusion von Wurzelfüllmaterial, auswirken. Ferner sollten diese Aspekte neben weite-ren zahn- und patientenbezogenen Variablen bezüglich ihres Einflusses auf die Erfolgs-rate der endodontischen Therapie analysiert werden. Es konnten keine signifikanten Unterschiede der endodontischen Erfolgsraten zwischen den hier untersuchten Obturationsmethoden ermittelt werden (p = ,16). In der SCGP-Kohorte lag die Erfolgsrate bei 85 % (34/40) verglichen mit 68,8 % (44/64) für CWR und 80 % (8/10) für SCGF. Die Homogenität der Obturation (p = ,2) und die Extrusion von Wurzelfüllmaterial in das periapikale Gewebe (p = ,93) zeigten keine Abhängigkeit von der gewählten Obturationstechnik. Die Länge der Wurzelkanalfüllung hingegen unter-schied sich signifikant zwischen den Kohorten (p = ,04*). Die Obturation mittels SCGP-Technik erzielte den höchsten Anteil adäquater Wurzelkanalfüllungen (92,5 %, 37/40) gegenüber SCGF (80 %, 8/10) und CWR (71,88 %, 46/64). Die CWR-Methode zeigte mit 18,8 % (12/64) den höchsten Anteil an unterfüllten Obturationen (SCGP: 7,5 %, 3/40; SCGF: 0 %). Unabhängig von der Obturationsmethodik zeigte sich der endodontische Behandlungs-erfolg im Allgemeinen unbeeinflusst von der Qualität der Wurzelkanalfüllungen. Die Va-riablen Obturationslänge (p = ,12) und -homogenität (p = ,11) sowie die Extrusion von Wurzelfüllmaterial in die periapikale Region (p = 1,00) zeigten keinen signifikanten Ein-fluss auf die Erfolgsrate. Das Durchschnittsalter im Patientenkollektiv betrug 60 Jahre mit einer tendenziellen Überrepräsentation weiblicher Probandinnen (60,5 %, 69/114). 73 % (81/111, 3 Mis-sings) der Studienteilnehmer/-innen wurden ab einem PSI-Grad von 3 als parodontal erkrankt eingestuft und 23,7 % (27/114) zeigten eine positive Raucheranamnese. Der BMI betrug im Durchschnitt 26,3 kg/m2. 42,3 % (47/111, 3 Missings) der Studienteil-nehmer/-innen wurden anhand der Einnahme von Medikamenten zur Therapie bzw. Prävention von kardiovaskulären Erkrankungen und/oder oraler Antidiabetika als chro-nisch erkrankt klassifiziert (chronic disease medication, CDM). Das Recallintervall be-trug durchschnittlich 6,3 Jahre mit einem Minimum von 4,7 und einem Maximum von 8,7 Jahren. Die patientenbezogenen Variablen Alter (p = ,45), Geschlecht (p = ,67), Pa-rodontitis (p = ,08), BMI (p = ,58), CDM (p = ,19), Recallintervall (p = ,08) und Rauchen (p = ,34) zeigten keinen signifikanten Einfluss auf den endodontischen Behandlungser-folg. Unter den zahnbezogenen Variablen beeinflusste lediglich der präoperative apikale Sta-tus den endodontischen Erfolg signifikant (p = ,007*). Zähne mit präoperativer apikaler Läsion zeigten eine Erfolgsrate von 66,2 % (47/71) gegenüber 90,7 % (n = 39/43) bei Fällen ohne apikale Läsion. Die Misserfolgswahrscheinlichkeit bei Vorliegen einer präoperativen Läsion war um den Faktor 4,98 erhöht (OR = 4,98, 95 % KI: 1.60, 15,57, p = ,006*). Zwischen Kompositfüllungen, Teilkronen, Vollkronen, Teleskopkronen und Brückenversorgungen konnten keine relevanten Unterschiede in den Erfolgsraten er-mittelt werden (p = ,29). Gleiches galt für adäquate (76,6 %, 82/107) und inadäquate (57,1 %, 4/7) Restaurationen (p = ,36). Ebenso zeigten die Erfolgsraten von Wurzelka-nalrevisionen (70,5 %, 31/44) und Primärbehandlungen (78,6 %, 55/70) keine signifikan-ten Abweichungen voneinander (p = ,45). Molaren waren im Studienkollektiv mit 56,1 % (64/114) gegenüber Prämolaren und Frontzähnen mit je 21,9 % (25/114) überrepräsen-tiert. Der Zahntyp (p = ,07) und die Ausgangsdiagnose (p = ,22) stellten keine relevanten Einflussfaktoren des endodontischen Erfolgs dar.
Objective:
High precise evaluation of the nasopalatine canal morphology is essential to perform detailed diagnosis and treatment plans in implantology and the orthodontic field. We aimed to study morphometric analysis measurements of the nasopalatine canal.
Material and methods:
In this cross-sectional study, maxillary CBCT images from 125 patients were evaluated in the Maxillofacial Radiology department between 2014-2021. Sagittal views were assessed to determine nasopalatine canal morphology and dimensions. The difference in canal diameter and length between genders was evaluated using an One Way ANOVA test.
Results:
There was no significant sex difference among all 125 cases in nasopalatine canal diameter, length, anterior bone plate width. The average length of the nasopalatine canal was 16.49±2.8 mm in male, 16.20±2.9 mm in female, incisive foramen diameter in the sagittal plane was 4.04±0.9 mm in male, 4.02±0.9 mm in female, nasopalatine foramen diameter was 4.63±1.4 mm in male, 4.75±1.2 mm in female. The width of the bone anterior to the canal was 5.89±1.4 mm in males, 5.69±1 mm in females.
Conclusion:
16-48 aged Mongolian average length of the nasopalatine canal was 16.3 mm, and average incisive foramen width was 4.08 mm, the average width of the bone anterior to the canal was 5.76 mm. Anterior retraction treatment for upper incisor root can be done safely without root resorption around 5.5 mm in the premaxillary alveolar bone.
The conical beam computed tomography (CBCT) technique presents an innovation of tomographic imaging systems and subsequent volumetric image reconstruction for dentistry. When compared with other methods of tomographic imaging CBCT is characterized by rapid volumetric image acquisition from a single low radiation dose scan of the patient. The NewTom (NewTom 9000; Quantitative Radiology, Verona, Italy) is an example of such a CBCT machine dedicated to dental and maxillofacial imaging, particularly for surgical and/or prosthetics implant planning in the field of dentistry. The aim of this study was to evaluate the accuracy of the linear measurements obtained in CBCT images using a NewTom.
Thirteen measurements were obtained in dry skulls (n = 8) between internal and external anatomical sites using a caliper. These were considered as real measurements. Then the dry skulls were submitted to CBCT imaging examinations. Radiographic distance measurements of the same dry skull anatomical sites were made using the NewTom QR-DVT 9000 software of the 2 mm-CTs axial section images and sagittal or coronal reconstructions. The data were compared by paired Student's t-test.
The results showed that the real measurements were always larger than those for the CBCT images, but these differences were only significant for measurements of the internal structures of the skull base.
The conclusion of this study is that, although the CBCT image underestimates the real distances between skull sites, differences are only significant for the skull base and therefore it is reliable for linear evaluation measurements of other structures more closely associated with dentomaxillofacial imaging.
Treatment options in orthodontics have been expanded by skeletal anchorage via mini-implants over the last few years. Sufficient primary stability is imperative to minimize implant loss rate. The aim of this study was to quantitatively analyze the factors influencing primary stability: bone quality, implant-design, diameter, and depth of pilot drilling.
Thirty-six pelvic bone segments (ilium) of country pigs were dissected and embedded in resin. To determine the primary stability, we measured the insertion torque of five different mini-implant types (tomas-pin [Dentaurum, Ispringen, Germany] 08 and 10 mm, and Dual Top [Jeil Medical Corporation, Seoul, Korea] 1.6 x 8 and 10 mm plus 2 x 10 mm). Twenty-five or 30 implants were inserted into each pelvic bone segment following preparation of the implant sites using pilot drill diameters of 1.0, 1.1, 1.2 and 1.3 mm and pilot drill depths of 1, 2, 3, 6 and 10 mm. Five implants were inserted for reference purposes to establish comparability. Thicknesses of bone compacta were measured via micro-computer tomography.
Insertion torques of orthodontic mini-implants and therefore primary stability varied greatly, depending on bone quality, implant-design, and preparation of implant site. Compared with the tomas-pin, the Dual Top screw showed significantly greater primary stability. Torque moments beyond 230 Nmm caused fractures of 9 Dual Top screws.
Compacta thickness, implant design and implant site preparation have a strong impact on the primary stability of mini-implants for orthodontic anchorage. Depending on the insertion site and local bone quality, the clinician should choose an optimum combination of implant and pilot-drilling diameter and depth.
This study involved 331 individuals who were without clinical evidence of gingival inflammation. The width of the keratinized gingiva and the depth of the gingival sulcus were measured on the mid-facial aspect of all teeth in each patient, using a calibrated, flat periodontal probe. The mean width of the attached gingiva did not show an increase from the deciduous to the permanent dentition. However, the width of the attached gingiva in the case of newly erupted permanent teeth was narrower than in the corresponding primary teeth. The widest zone of attached gingiva was found over the central and lateral incisors. The width of the attached gingiva decreased over the canine and the first premolar (and first primary molar). It then increased over the second pre-molar (and second primary molar) and the first molar. These variations were approximately the same in both the maxilla and the mandible, although there was a greater over-all width of attached gingiva in the maxilla than in the mandible. The tendancy, in the permanent dentition, for the attached gingiva to increase in width with age was related to a concomitant decrease in sulcus depth.
This study involved 331 individuals who were without clinical evidence of gingival inflammation. The width of the keratinized gingiva and the depth of the gingival sulcus were measured on the mid-facial aspect of all teeth in each patient, using a calibrated, flat periodontal probe. The mean width of the attached gingiva did not show an increase from the deciduous to the permanent dentition. However, the width of the attached gingiva in the case of newly erupted permanent teeth was narrower than in the corresponding primary teeth. The widest zone of attached gingiva was found over the central and lateral incisors. The width of the attached gingiva decreased over the canine and the first premolar (and first primary molar). It then increased over the second premolar (and second primary molar) and the first molar. These variations were approximately the same in both the maxilla and the mandible, although there was a greater over-all width of attached gingiva in the maxilla than in the mandible. The tendency, in the permanent dentition, for the attached gingiva to increase in width with age was related to a concomitant decrease in sulcus depth.
summary Longitudinally documented benefits for edentulous patients of treatment outcomes of the osseointegration technique demonstrate compelling therapeutic results. Heterogeneous population groups, treated in different centres by various dental specialists, have provided impressive evidence of a minimal burden of illness associated with the procedure. A critical appraisal of the many
components of any implemented treatment paradigm demands repeated analysis of the factors which enable patients' informed consent and dentists' optimal decision making. This paper reviews those salient aspects which impact upon decision making with implant-supported prostheses. It emphasizes the predominance of bone structure in selecting the most likely favourable treatment outcome.
Ten autopsy jaw specimens (6 mandibles, 4 maxillae) were used for cutting resistance measurements during low-speed threading. Overall, 31 sites were analyzed where implants were inserted into threaded canals. Bone area measurements were performed around the implants as described previously. The cutting resistance values together with the total bone area values were found to be higher in mandibles than in maxillae, and a tendency towards higher values was seen in incisor regions compared with premolar regions. Furthermore, an intraindividual comparison between the true cutting resistance and the bone density values of prepared sites showed a statistically significant correlation. The method with cutting resistance measurements for evaluation of bone quality seems therefore to be reliable, at least when used in human autopsy jaw bone specimens.
The present study examined the influence of bone quality on the transmission of occlusal forces for endosseous dental implants. Employing the finite element method, the study modeled a 3.75 x 10-mm threaded implant placed in a 12 x 11 x 8-mm section of bone. By varying the elastic parameters assigned to the bone elements, four bone quality categories were established. A load of 100 N was applied at the occlusal surface of the restoration at a 30 degrees angle to the vertical axis of the implant. Maximum von Mises stress concentrations (sigma Emax) were observed to be located in the marginal bone at the coronal aspect of the implant fixture in all four cases. Values of sigma Emax were 13.7 MPa for type 1 bone, 15.8 MPa for type 2 bone, 20.1 MPa for type 3 bone, and 26.5 MPa for type 4 bone. Magnitude of the stresses in bone was strongly correlated (r = 0.997) with computed displacement of the implant system. This analysis predicts that placement of implants in bone with greater thickness of the cortical shell and greater density of the core will result in less micromovement and reduced stress concentration, thereby increasing the likelihood of fixture stabilization and tissue integration.
To correlate torque forces during insertion of screw-type dental implants with bone mineral density (BMD) values determined preoperatively.
Dental quantitative computed tomography (CT) was performed with simultaneous imaging of five postmortem mandibles and a calibration standard containing defined concentrations of calcium hydroxyapatite. CT numbers were converted to local BMD values by assuming a linear relationship (BMD = a x HU + b), where a and b are calibration coefficients. The a, b, P, and t values, correlation coefficients, and standard errors were calculated. Dental implants (n = 25) were set, and insertion torques were recorded. BMD was determined at the implantation site and correlated with torque forces recorded during implant insertion. Calibration coefficients derived for specimens were compared with those derived for actual patients.
Calibration coefficients (at 120 kV) for the postmortem specimens were a = 0.760 +/- 0.03 (mean +/- SD) and b = 2.8 +/- 3.7 and for the patients were a = 0.804 +/- 0.06 and b = 5.2 +/- 4.2. Calibrated BMD values at the location of dental implants exhibit a significant correlation (R(2) = 0.83, P <.001) with insertion torques on the basis of a second-order model, which yields torque = (0.0055 x BMD + 0.73)(2) for the implants used and the surgical technique applied.
Correlation exists between BMD measured with dental quantitative CT and the insertion torque of dental implants.
The Straumann Orthosystem (Institut Straumann, Waldenburg, Switzerland) describes a technique that involves placement of titanium implants (4 or 6 mm long and 3.3 mm in diameter) into the midsagittal hard palate for orthodontic anchorage. The aim of this study was to determine the quantity of bone in the midline of the anterior hard palate, and specifically the thickness inferior to the incisive canal.
Twenty-five dry skulls were radiographed with a standardized cephalometric technique. The vertical thickness of the midsagittal palate was then measured to the nearest tenth of a millimeter. Next, gutta-percha was injected into the incisive canal, and the radiograph was repeated. The bone thicknesses were then measured from the inferior hard palate to the most Inferior part of the radiopaque canal. This is defined as the actual bone available for the implant without violating the canal.
The measurements have shown that an average of 8.6 +/- 1.3 mm of bone is theoretically available for the implant. However, considering the canal (where only bone thickness inferior to it is utilized and measured), only 4.3 +/- 1.6 mm of bone exists. The canal itself averaged 2.5 +/- 0.6 mm in diameter.
Prior studies have overestimated the amount of bone available for implants in the median hard palate. The main reason for this is that the incisive canal is not well visualized on cephalometric radiographs of live patients.
This study supports the continued use of implants, as approximately 50% of skulls still had the requisite minimum 4 mm of bone inferior to the incisive canal for maximum osseointegration with the 4-mm implants. However, 6-mm implants should be used with caution.
Dental esthetics are often impaired by a disharmonious contour of the gingival margin in the anterior region. However, the soft tissue contour can be improved by orthodontic eruption of the relevant teeth prior to prosthodontic treatment. The successful use of an orthodontic microscrew implant as anchorage for the eruption appliance is demonstrated in a case report.
Monocortical screws are increasingly being used to enhance orthodontic anchorage. The most frequently cited clinical complication is soft tissue irritation. It is thus clinically advantageous for these miniscrews to be placed in attached mucosa. The purpose of this study was to (1) determine radiographically the most coronal interradicular sites for placement of miniscrews in orthodontic patients and (2) determine if orthodontic alignment increases the number of sites with adequate interradicular bone for placement of these screws. Sixty panoramic radiographs (n = 30 pretreatment, n = 30 posttreatment) of orthodontic patients were obtained from an archival database after Institutional Review Board approval. Selection criteria included minimal radiographic distortion and complete eruption of permanent second molars. Interradicular sites were examined with a digital caliper for presence of three and four mm of bone. If three or four mm of bone existed, then a vertical measurement from the cementoenamel junction (CEJ) to first measurement was made. In addition, the magnification error inherent in panoramic radiographs was estimated. Ninety-five percent confidence intervals were calculated for the vertical distances from the CEJ to the horizontal bone location. Bone stock for placement of screws was found to exist primarily in the maxillary (mesial to first molars) and mandibular (mesial and distal to first molars) posterior regions. Typically, adequate bone was located more than halfway down the root length, which is likely to be covered by movable mucosa. Inability to place miniscrews in attached gingiva may necessitate design modifications to decrease soft tissue irritation.
The purpose of this study was to quantify the treatment effects of distalization of the maxillary and mandibular molars using microscrew implants. The success rate and clinical considerations in the use of the microscrew implants were also evaluated. Thirteen patients who had undergone distalization of the posterior teeth using forces applied against microscrew implants were selected. Among them, 11 patients had mandibular microscrew implants and four patients had maxillary implants, including two patients who had both maxillary and mandibular ones at the same time. The maxillary first premolar and first molars showed significant distal movement, with no significant distal movement of the anterior teeth. The mandibular first premolar and first and second molars showed significant distal movement, but no significant movement of the mandibular incisor was observed. The microscrew implant success rate was 90% over a mean application period of 12.3 +/- 5.7 months. The results might support the use of the microscrew implants as an anchorage for group distal movement of the teeth.
This clinical study is the first to quantitatively evaluate both regional bone structure by computed tomography preoperatively and dental implant stability by resonance frequency analysis at the time of surgery to explore the relation between local bone structure and dental implant stability in humans. Implant stability at the time of installation is often difficult to achieve in lower density bone and implant stability might influence treatment efficacy. Few clinical studies have reported detailed bone characteristics obtained using computed tomography prior to surgery and comprehensive implant stability measurements at the time of surgery. We hypothesized that thicker cortical bone would improve the stability of the dental implant at the time of placement. Before radiographic examination, diagnostic radiographic templates were made by incorporating radiopaque indicators. Computed tomography scans were obtained for 50 edentulous subjects prior to surgery. Preoperatively, the thickness of the cortical bone at the sites of implant insertion was measured digitally, and then implant insertion surgery was performed. A total of 225-implant stability measurements were made using a resonance frequency analyzer. There was a strong linear correlation between cortical bone thickness and resonance frequency (r = 0.84, P < 0.0001). The implant length had a weak negative correlation with stability (r = -0.25, P < 0.0005). These results suggest that the initial stability at the time of implant installation is influenced more by cortical bone thickness than by implant length. The cortical and cancellous ratio of local bone is extremely important for implant stability at the time of surgery and determining the local bone condition is critical for treatment success.
The aim of this study was to provide an anatomical map to assist the clinician in miniscrew placement in a safe location between dental roots. Volumetric tomographic images of 25 maxillae and 25 mandibles taken with the NewTom System were examined. For each interradicular space, the mesiodistal and the buccolingual distances were measured at two, five, eight, and 11 mm from the alveolar crest. In this article, measurements distal to the canines are presented. In the maxilla, the greatest amount of mesiodistal bone was on the palatal side between the second premolar and the first molar. The least amount of bone was in the tuberosity. The greatest thickness of bone in the buccopalatal dimension was between the first and second molars, whereas the least was found in the tuberosity. In the mandible, the greatest amount of mesiodistal dimension was between first and second premolar. The least amount of bone was between the first premolar and the canine. In the buccolingual dimension, the greatest thickness was between first and second molars. The least amount of bone was between first premolar and the canine. Clinical indications for a safe application of the miniscrews are provided, as well as the ideal miniscrew features.
The purpose of this study was to quantitatively evaluate cortical bone thickness in various locations in the maxilla and the mandible. In addition, the distances from intercortical bone surface to root surface, and distances between the roots of premolars and molars were also measured to determine the acceptable length and diameter of the miniscrew for anchorage during orthodontic treatment.
Three-dimensional computed tomographic images were reconstructed for 10 patients. Cortical bone thicknesses were measured in the buccal and lingual regions mesial and distal to the first molar, distal to the second molar, and in the premaxillary region at 2 different levels. Differences in cortical bone thickness at 3 angles (30 degrees, 45 degrees, and 90 degrees) were also assessed. Distances of the intercortical bone surface to the root surface and the root proximity were also measured at the above areas.
Significantly less cortical bone thickness was observed at the buccal region distal to the second molar compared with other areas in the maxilla. Significantly more cortical bone was observed on the lingual side of the second molar compared with the buccal side. In the mandible, mesial and distal to the second molar, significantly more cortical bone was observed compared with the maxilla. Furthermore, significantly more cortical bone was observed at the anterior nasal spine level than at Point A in the premaxillary region. Cortical bone thickness resulted in approximately 1.5 times as much at 30 degrees compared with 90 degrees Significantly more distance from the intercortical bone surface to the root surface was observed at the lingual region than at the buccal region mesial to the first molar. At the distal of the first mandibular molar, significantly more distance was observed compared to that in the mesial, and also compared with both distal and mesial in the maxillary first molar. There was significantly more distance in root proximity in the mesial area than in distal area at the first molar, and significantly more distance was observed at the occlusal level than at the apical level.
These data show that the safest location for placing miniscrews might be mesial or distal to the first molar, and an acceptable size of the miniscrew is less than approximately 1.5 mm in diameter and approximately 6 to 8 mm in length.
The purposes of this study were to examine the success rates and find factors affecting the clinical success of screw implants used as orthodontic anchorage.
Eighty-seven consecutive patients (35 male, 52 female; mean age, 15.5 years) with a total of 227 screw implants of 4 types were examined. Success rates during a 15-month period of force application were determined according to 18 clinical variables.
The overall success rate was 91.6%. The clinical variables of screw-implant factors (type, diameter, and length), local host factors (occlusogingival positioning), and management factors (angle of placement, onset and method of force application, ligature wire extension, exposure of screw head, and oral hygiene) did not show any statistical differences in success rates. General host factors (age, sex) had no statistical significance. Mobility, jaw (maxilla or mandible), and side of placement (right or left), and inflammation showed significant differences in success rates. Mobility, the right side of the jaw, and the mandible were the relative risk factors in the logistic regression analysis when excluding mobility, inflammation around the screw implants was added to the risk factors.
To minimize the failure of screw implants, inflammation around the implant must be controlled, especially for screws placed in the right side of the mandible.
To obtain sufficient stability of implants, the thickness of the soft tissue and the cortical bone in the placement site must be considered. However, the literature contains few anatomical studies of orthodontic implants.
To measure soft-tissue and cortical-bone thicknesses, maxillae from 23 Korean cadavers were decalcified, and buccopalatal cross-sectional specimens were obtained. These specimens were made at 3 maxillary midpalatal suture areas: the interdental area between the first and second premolars (group 1), the interdental area between the second premolar and the first molar (group 2), and the interdental area between the first and second molars (group 3).
In all groups, buccal soft tissues were thickest closest to and farthest from the cementoenamel junction (CEJ) and thinnest in the middle. Palatal soft-tissue thickness increased gradually from the CEJ toward the apical region in all groups. Buccal cortical-bone was thickest closest to and farthest from the CEJ and thinnest in the middle in groups 1 and 2. Palatal cortical-bone thickness was greatest 6 mm apical to the CEJ in groups 1 and 3, and 2 mm apical to the CEJ in group 2. Along the midpalatal suture, palatal mucosa remained uniformly 1 mm thick posterior to the incisive papilla.
Surgical placement of miniscrew implants for orthodontic anchorage in the maxillary molar region requires consideration of the placement site and angle based on anatomical characteristics.
A 16-year-old girl with an anterior open bite was treated with nonextraction therapy that included intrusion of the maxillary and mandibular posterior teeth with microscrew implants. Implants (diameter, 1.2 mm; length, 8 or 6 mm) were placed into alveolar bone near the posterior teeth and used as anchorage for intrusive force. To prevent adverse side effects of buccoversion or linguoversion of the posterior teeth during intrusion, a transpalatal bar and a lingual arch were placed. The 3-mm anterior open bite was corrected in 11 months of treatment, after intrusion of the maxillary and mandibular posterior teeth and autorotation of the mandible. The posterior intrusion relapsed in the early stage of retention, at 8 months; thereafter, no obvious relapse was evident in the vertical position of the molars and the FMA. The treatment mechanics of anterior open bite with posterior intrusion by using microscrew implants were effective but still require a proper retention protocol.
To evaluate the effectiveness of miniscrew anchorage for intrusion of the posterior dentoalveolar region to correct skeletal open bite.
The study was comprised of 12 patients (aged 14.3 to 27.2 years; mean 18.7 years) with anterior open bites. All the patients presented a Class II skeletal pattern and excessive posterior growth. Self-drilling miniscrew implants were inserted into the posterior midpalatal area and the buccal alveolar bone between the lower molars. A transpalatal and a lingual arch were used to maintain the molars on each side in order to avoid overrotation during intrusion. A force of 150 g was applied to the microscrews on each side to intrude the posterior teeth. Lateral cephalograms of all 12 patients were taken preintrusion and immediately after completion of the intrusion. The cephalometric films were measured and compared.
The results showed that the anterior open bites in 12 patients were all corrected in a mean of 6.8 months. Overbite increased by a mean of 4.2 mm (P < .001), from -2.2 mm in preintrusion to 2.0 mm in postintrusion. The maxillary and mandibular first molars were intruded for an average of 1.8 mm (P < .001) and 1.2 mm (P < .001), respectively. The mandibular plane angle was reduced by 2.3 degrees (P < .001), which led to a counterclockwise rotation of the mandible with a significant decrease in the anterior facial heights (mean of 1.8 mm; P < .001).
Miniscrew anchorage has the advantages of being a simpler procedure, being minimally invasive, and requiring minimal patient cooperation.
The aim of this study was to determine the bone density in the designated implant sites using computerized tomography (CT), the fastening torque values of dental implants, and the implant stability values using resonance frequency analysis. Further aim was to evaluate a possible correlation between bone density, fastening torque and implant stability. Eighty-five patients were treated with 158 Brånemark System implants. CT machine was used for preoperative evaluation of the jawbone for each patient, and bone densities were recorded in Hounsfield units (HU). The fastening torque values of all implants were recorded with the OsseoCare equipment. Implant stability measurements were performed with the Osstell machine. The average bone density and fastening torque values were 751.4 +/- 256 HU and 39.7 +/- 7 Ncm for 158 implants. The average primary implant stability was 73.2 +/- 6 ISQ for seventy implants. Strong correlations were observed between the bone density, fastening torque and implant stability values of Brånemark System TiUnite MKIII implants at implant placement (P < 0.001). These results strengthen the hypothesis that it may be possible to predict and quantify initial implant stability and bone quality from pre-surgical CT diagnosis.
Placing orthodontic mini-implants allows clinicians to use simple and esthetic appliances to retract anterior teeth. This usage is reported here in a patient with lip protrusion and mild crowding. The anterior teeth were splinted on the lingual side and retracted by an elastomeric chain connected to orthodontic mini-implants without the use of an archwire or brackets. After space closure, brackets were bonded for detailing individual teeth. The desired movement of the anterior teeth was achieved by changing the application point of the retraction force and adjusting the line of force.
The palate is a suitable site for the placement of orthodontic mini-implants. This study was conducted to assess the bone thickness of the palate to provide a more reliable guide for mini-implant placement.
Computed tomographic records of 18 adults (9 men, 9 women) 18 to 35 years old (mean age, 26.8 +/- 4.0 years) were used to measure the bone thickness of the midpalatal area and its vicinity posterior to the incisive foramen. Bone thickness was measured at 80 coordinates at regular mediolateral and anteroposterior intervals along the midpalatal suture. After the mean, minimum, and maximum values were obtained for the entire group and for the male and female groups, mediolateral and anteroposterior comparison was done, and the differences between sexes were evaluated.
Individual variations were so great that high-resolution computed tomographic images are recommended for safety. Significant differences were seen between the male and female groups. The midpalatal area within 1 mm of the midsagittal suture had the thickest bone available in the whole palate. The thickness tended to decrease laterally and posteriorly. Maps of mean palatal bone thickness were made for visual comparison of placement locations and for selection of the mini-implant length.
When a mini-implant could deviate from the midpalatal area by more than 1 mm, we recommend placing it not far posteriorly or using a shorter mini-implant.
Our aim was to review the experimental literature to determine what is known about functional and morphological tissue reactions around orthodontically loaded temporary skeletal anchorage devices.
The PubMed electronic database and the reference citations in published articles were searched to the end of April 2006. The inclusion criteria were animal studies about orthodontically loaded skeletal anchorage consisting of metallic bone plates or screw implants of 2.2 mm diameter or less. Data on healing time, force application, stability, side effects, and osseointegration were collected by 2 independent readers.
Eight articles met the selection criteria. The healing times ranged from 0 to 12 weeks, and the amount of force varied from 25 to 500 g. Implant stability was generally achieved without severe side effects. Direct bone-screw contact was reported to be 10% to 58%, and osseointegration increased with loading time. Nevertheless, no significant difference in bone-screw contact was found between loaded and unloaded screw implants, or between tension and pressure sides of loaded implants.
This review highlights some positive experimental findings that apply in clinical practice. However, questions concerning optimal force systems, surgical techniques and placement, and healing times remain. Future research should be well controlled and based on standardized protocols to test specific hypotheses.
The risks associated with miniscrew placement should be clearly understood by both the clinician and the patient. Complications can arise during miniscrew placement and after orthodontic loading that affect stability and patient safety. A thorough understanding of proper placement technique, bone density and landscape, peri-implant soft-tissue, regional anatomic structures, and patient home care are imperative for optimal patient safety and miniscrew success. The purpose of this article was to review the potential risks and complications of orthodontic miniscrews in regard to insertion, orthodontic loading, peri-implant soft-tissue health, and removal.
Mini-implant-enhanced anchorage has become a popular concept in orthodontics over the past years. Although these systems are routinely used in university settings, there is some reservation because of lack of information in private practices. This article will introduce the concept of mini-implant anchorage to the orthodontic practitioner.
Patient selection and preparation Tissue-integrated prosthesis: osseointegration in clinical dentistry. Chicago: Quin-tessence
- U Lekholm
- Zarb
- Ga
Lekholm U, Zarb GA. Patient selection and preparation. In: Branemark PI, Zarb GA, Albrektsson T, editors. Tissue-integrated prosthesis: osseointegration in clinical dentistry. Chicago: Quin-tessence; 1985. p. 199-209.
Systematic review of the experimental use of temporary skeletal anchorage devices in orthodontics
- M A Cornelis
- N R Scheffler
- De Clerck
- H J Tulloch
- J F Nyssenbehets
Cornelis MA, Scheffler NR, De Clerck HJ, Tulloch JF, NyssenBehets C. Systematic review of the experimental use of temporary
skeletal anchorage devices in orthodontics. Am J Orthod Dentofacial Orthop 2007;131(4 Suppl):S52-8.
Tissue-integrated prosthesis: osseointegration in clinical dentistry. Chicago: Quintessence
- U Lekholm
- G A Zarb
Lekholm U, Zarb GA. Patient selection and preparation. In:
Branemark PI, Zarb GA, Albrektsson T, editors. Tissue-integrated
prosthesis: osseointegration in clinical dentistry. Chicago: Quintessence; 1985. p. 199-209.