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Miniscrew implants: The Aarhus anchorage system
Abstract
The limitations of orthodontics, as determined by anchorage problems, have become more obvious as the number of adults seeking treatment increases. Different types of intraoral-extradental anchorage, such as infrazygomatic crest ligature wires, miniplates, and miniscrews, have been suggested to overcome the limitations of traditional orthodontic anchorage. In the present article, the development of a miniscrew anchorage system is outlined. Based on the results of monkey experiments and finite element analysis, the locations for miniscrew placement and loading protocols are discussed. These studies suggest that immediate loading with known forces increases the bone density surrounding the miniscrews. Treatment planning, indications for skeletal anchorage, miniscrew biomechanics, and possible complications with the Aarhus anchorage® system are discussed.
... It seems that just like this type of gingiva is a very essential factor for periodontal health; similarly, the presence of keratinized gingiva around the miniscrews is important for the health of the surrounding tissues and, therefore, the stability and long-term maintenance without inflammation Melsen and Verna(2005). ...
... Cortical bone thickness(CBT)are important for the success of miniscrew implants because,Implanting in cortical bone more than 1 mm cortex thickness improved the miniscrew success rate as (Miyawakiet al., 2003;Melsen and Verna, 2005;Motoyoshiet al., 2007;Brettin et al.,2008). ...
... The proposed results showed that the 2 mm CBT bone block revealed the lowest bone stress andminiscrewdisplacement as compared with 1 mm although using different miniscrew diameters and among various insertion angulations Table ( Miyawakiet al.,(2003), Miyamoto et al., (2005), Melsen and Verna (2005), Motoyoshi et al., (2007), Ono et al., (2008), Motoyoshi et al., (2009) suggested that the minimum threshold of cortical bone thickness to improveminiscrewssuccess rate was 1 mm, as the primary stability of them depends largely on local bone properties (cortical bone thickness). ...
Evaluation of the stress in the bone and miniscrew displacement of different miniscrew diameters that
inserted in two bone models of 1 and 2 mm of cortical bone thickness at different angulations to the bone.
... The removal procedure can be achieved without the use of anesthesia, but topical or local anesthesia can be used-especially when there is tissue covering the miniscrew implant. 18,19 The miniscrew implant is unscrewed using the screwdriver of the corresponding manufacturer. In the event it cannot be removed, it is advised to wait 3 to 7 days after the initial attempt of its removal, because it is believed that microfractures or bone remodeling as a result of the initial attempt will cause the screw to loosen. ...
... In the event it cannot be removed, it is advised to wait 3 to 7 days after the initial attempt of its removal, because it is believed that microfractures or bone remodeling as a result of the initial attempt will cause the screw to loosen. 18 If the miniscrew implant fractures during removal, a small surgical procedure to remove it may be necessary. ...
This is the continuation of the first part of our article and includes the design and function of screw-type orthodontic mini-implants, placement sites, surgical procedures, loading approaches and a little about biocortical and resorbable implants.
... To address this and develop means of prevention, several studies have investigated the biomechanics of mini-screw fixation. This has led to various improvements in the form of modifications to the shape [5][6][7] and length [8] of screws, consideration of bone condition at the fixation site [9][10][11][12][13], and optimization of screw angle and torque [14][15][16][17][18] during implantation. Nonetheless, mini-screws still fail in some cases, usually as a result of inflammation, infection, and shedding [19][20][21][22][23][24][25]. ...
... Since the mini-screw first came to be used as a fixation anchor in orthodontic treatment, various studies on the optimization of its implantation have been reported [5][6][7][8][9][10][11][12][13][14][15][16][17]. However, clinically undesirable cases in which screws drop out or break still occur, and the cause of this is unclear. ...
This study aimed to determine whether the positional relationship between the underside of the screw head and the surface of the alveolar bone could alter the stress on the two surfaces and affect the stability of implanted anchor screws. First, in order to confirm the extent of the gap between the mini-screw and the bone surface, a mini-screw was placed in the palate of rabbits and examined histologically. As a result, in the conventional screw implantation procedure, oral mucosa between the base of the screw head and the bone creates a spatial gap. Removal of the oral mucosa eliminates this gap. Then, we compared the positional difference of the screw in a contact and gap group by analyzing stress distribution on the bone and screw. Analysis using the finite element method showed that more stress was loaded on both the bone and screw in the gap group than in the contact group. Cortical bone thickness did not affect stress in either group. The effects of different load strengths were similar between groups. A surgical procedure in which mucosal coverings are removed so that implanted anchor mini-screws are in contact with the bone surface was found to reduce the stress load on both the bone and screw. This procedure can be used to prevent undesirable dislodgement of implanted mini-screws.
... To address this and develop means of prevention, several studies have investigated the biomechanics of mini-screw xation. This has led to various improvements in the form of modi cations to the shape [5][6][7] and length [8] of screws, consideration of bone condition at the xation site [9][10][11][12][13], and optimization of screw angle and torque [14][15][16][17][18] during implantation. Nonetheless, mini-screws still fail in some cases, usually as a result of in ammation, infection, and shedding [19][20][21][22][23][24][25]. ...
... Since the mini-screw rst came to be used as a xation anchor in orthodontic treatment, various studies on the optimization of its implantation have been reported [5][6][7][8][9][10][11][12][13][14][15][16][17]. However, clinically undesirable cases in which screws drop out or break still occur, and the cause of this is unclear. ...
Objectives: This study aimed to determine whether the positional relationship between the underside of the screw head and the surface of the alveolar bone could alter the stress on the two surfaces and affect the stability of implanted anchor screws.
Materials and Methods: Animal experiments show that, in the conventional screw implantation procedure, oral mucosa between the base of the screw head and the bone creates a spatial gap. Removal of the oral mucosa eliminates this gap. We compared the positional difference of the screw in a contact and gap group by analyzing stress distribution on the bone and screw.
Results: Analysis using the finite element method showed that more stress was loaded on both the bone and screw in the gap group than in the contact group. Cortical bone thickness did not affect stress in either group. The effects of different load strengths were similar between groups.
Conclusions: A surgical procedure in which mucosal coverings are removed so that implanted anchor mini-screws are in contact with the bone surface was found to reduce stress load on both the bone and screw.
Clinical Relevance: This procedure can be used to prevent undesirable dislodgement of implanted mini-screws.
... Miniscrew models and bone blocks were created using SolidWorks (v.2016, SolidWorks Corp., Waltham, MA, USA). Five different miniscrew head designs-cross head, mushroom head, button head, bracket head, and through-hole or circle headwere drawn in their actual dimensions (see Figure 1 [15][16][17] ). All miniscrew models were cylindrical, with dimensions of 8 mm in length and 1.6 mm in length and diameter, respectively. ...
Objective:
To determine the optimum miniscrew head design in orthodontic treatments for primary stability and compare stress distribution on a representative bone structure.
Methods:
Miniscrews with cross heads, mushroom-shaped heads, button heads, bracket heads, and through-hole heads were compared using finite element analysis. Miniscrews, whose three-dimensional drawings were completed using the SolidWorks computer-aided software package, were inserted in the bone block. Orthodontic force was applied to the head, and stress distributions, strains, and total deformations were investigated.
Results:
The lowest von Mises stress of 5.67 MPa was obtained using the bracket head. On the other hand, the highest von Mises stress of 22.4 MPa was found with the button head. Through mesh convergence analysis, the most appropriate mesh size was determined to be 0.5 mm; approximately 230,000 elements were formed for each model.
Conclusion:
Because the need for low stress is substantial for the primary stability of the miniscrew, this study demonstrated that the bracket head miniscrew is the optimal head design. In addition, it is posited that the success rate of orthodontic anchorage treatments will increase when bracket head miniscrews are used.
... Для попередження гіпертрофії мʼяких тканин іноді використовують метод повного перекриття мініімплантату слизовою, а кріплення, під'єднані до головки мініімплантату, проходять через слизову оболонку. При відсутності достатньої остеоінтеграції можлива втрата стабільності та переміщення мініімпланту від 1 до 1.5мм [23]. Зазвичай, такі проблеми виникають протягом 100-150 днів після навантаження [24]. ...
When disruptions occur in the mechanisms regulating the eruption of lower jaw molars, it becomes necessary to artificially extract and reposition them within the dentition. Various treatment methods are employed for this purpose, with the primary approach involving traction fixed to teeth or other anchorage elements and bone supports. Skeletal support is preferred to minimize resistance from orthodontic appliances when applying force to the patient's teeth. The utilization of mini-implants for anchorage demonstrates a relatively high success rate, though instances of failures and complications are not unheard of. Potential issues such as stability loss and mini-implant displacement may necessitate relocation or adjustments to treatment strategies, posing challenges for both practitioners and patients. Unlike dental implants, where secondary stability often dictates treatment success, primary stability holds paramount importance for orthodontic mini-implants. Investigating primary stability parameters can significantly impact treatment strategy selection and orthodontic mini-implant loading timelines. Focusing solely on mini-implant torque during placement is inadequate, as it fails to comprehensively gauge real stability. Moreover, the available range of torque indicators for orthodontic mini-implant placement is limited, typically ranging from 5ncm to 10 ncm. Furthermore, the selection of specialized devices for measuring primary stability is limited and necessitates meticulous evaluation.
... The BCBT is an important factor in miniscrew stability and success. Some investigators have reported that as the BCBT increases, so does the miniscrew stability [10,11] because most of the force the miniscrew generates is transmitted to the cortical bone [22,23]. A systematic review yielded studies mentioning that miniscrew success may increase with adequate BCBT where the miniscrew is applied [24]. ...
Objectives
We aimed to determine safe areas to apply miniscrews in the interradicular region of the maxilla and mandible in individuals with various sagittal skeletal malocclusions.
Materials and methods
Cone beam–computed tomography images of 159 individuals were used. Individuals were divided into three groups: Class I, Class II, and Class III. In the sagittal plane, 3–6–9-mm apical sections were determined from the alveolar crest apex. The buccal cortical bone thickness, interradicular distance, and buccolingual bone distances were measured.
Results
In the buccal cortical bone thickness, we observed statistically significant differences between the classes except for the 1–1 region in the maxilla and all regions and sections in the mandible (p < 0.05). The differences in the buccolingual bone distance between classes were statistically significant, except for the 3-mm and 6-mm sections in the 3–4 and 4–5 regions of the maxilla, the 9-mm sections in the 1–2 and 2–3 regions, the 6-mm and 9-mm sections in the 3–4 region, and the 6-mm section in the 4–5 regions of the mandible (p < 0.05). The differences in the interradicular bone distance were statistically significant between the classes in all regions and sections of the mandible except the 6-mm sections in the 1–2 region and in all sections of the maxilla except the 6-mm sections in the 3–4 region (p < 0.05).
Conclusions
We observed significant differences in the buccal cortical bone thickness, interradicular bone distance, and buccolingual bone distance among individuals.
Clinical relevance
Understanding the anatomy of interradicular regions and preventing complications.
... Mini-screws, commonly employed as temporary anchorage devices in orthodontics, have shown a success rate of 85.21% [11]. Bone density increases around mini-screws that are loaded [12][13][14]. Studies have demonstrated comparable bone-implant contact between loaded and unloaded mini-screws [2,15]. ...
The aim of this study was to evaluate the impact of mini-screw placement on the alveolar ridge using a split-mouth design. Twelve beagles underwent bilateral extraction of their lateral teeth. In the immediate group, a mini-screw was unilaterally placed approximately 3–4 mm below the alveolar crest of the extraction site on the experimental side. The delayed group received mini-screws six weeks after tooth extraction. On average, the dogs were sacrificed after 11 weeks, and the maxillary bones were excised and scanned using cone-beam computed tomography (CBCT). Histopathological examinations were conducted to assess inflammation and bone formation scores. The results showed that in the immediate group, bone height was significantly greater on the intervention side compared to the control side (p < 0.05), whereas there was no significant difference in the delayed group. In both groups, there was a significant increase in bone density around the mini-screws compared to the control sides (p < 0.05). Mini-screw insertion led to a significant enhancement of bone growth in both groups (p < 0.05), with no notable differences between the two groups. The mini-screws did not have any impact on bone inflammation or width. Overall, both immediate and delayed mini-screw placement in the extraction socket positively influenced bone dimensions, density, and histological properties. However, immediate insertion was more effective than delayed placement in preserving vertical bone height, despite delayed insertion resulting in higher bone density.
... Іноді для попередження гіпертрофії мʼяких тканин використовується метод повного покриття мініімплантату слизовою, тоді як дроти або кріплення, під'єднані до головки мініімплантату, проходять через слизову оболонку. Також через відсутність належної остеоінтеграції можлива втрата стабільності та його переміщення від 1 до 1.5мм [57]. Більшість таких проблем виникає протягом 100-150 днів після навантаження [58]. ...
The problem of tooth eruption is a common issue affecting nearly 20% of the population. Along with this, there is a growing trend of increased dentoalveolar anomalies in children and adults. One of such anomalies is the retention of the mandibular molars, which has always been a complex dentoalveolar pathology posing clinical challenges for orthodontists and oral surgeons. The aim of this study is to review and analyze relevant literature sources regarding the current etiological factors, diagnostic methods and treatment options for the retention of the mandibular molars. Tooth eruption is a complex and highly regulated process, which is currently the subject of research by many authors. There are various theories about the process of tooth eruption, often contradicting each other. Retention of molars should be considered as a pathological phenomenon with a multifactorial aetiology. Consequently, the approach to the diagnosis and treatment of this pathology cannot be standardized or unified. Therefore, there is a tendency to personalized approach both in the diagnosis and treatment of patients with dentoalveolar anomalies. In most cases, the diagnosis of molar retention is based on a clinical and x-ray examination. Notably, decision-making and treatment strategy selection rely on constantly evolving methods. Unfortunately, the acceleration and early completion of bone tissue maturation increase the frequency of tooth retention, pushing clinicians towards the early intervention. This, in turn, requires a revision of existing recommendations and protocols. The development of technology and the modern possibilities of digital planning open up new horizons and provide tools for addressing complex challenges; however, they require a multidisciplinary approach to implementing non-standard treatment methods involving both orthodontists and oral surgeons. Apparently, all novel techniques require careful analysis, which provides researchers with space for further investigations.
... Studies have documented that the failure rate of TADs under orthodontic loading varies between 11% and 30%. [26][27][28][29][30] Unstable TADs should be removed and reinserted/ replaced. In this study, soft tissue coverage was the most common urgency linked to TADs, which is also a major risk factor for the mobility of miniimplants. ...
OBJECTIVES
This investigation aimed to evaluate the most common orthodontic urgencies, their management, and changes in routine biosafety measures and the total income of the dental office in South India during the COVID-19 pandemic.
METHODS
A questionnaire was drafted using Google Forms with questions in four domains pertaining to orthodontic urgencies, biosafety measures, treatment duration, and income. After validation, this questionnairewas sent to 750 orthodontists via WhatsApp messenger (WhatsApp Inc, Menlo Park, Calif) over a period of 14 days.Descriptive statistics and comparisons were performed using independent t- and Chi-square tests.
RESULTS
Majority of the orthodontists (62.3%) had closed their clinics only during the first lockdown. Many (63%) had scheduled urgent appointments along with routine limited patients per day. The most frequent urgencies were related to the breakage of brackets, archwires, molar tubes, bands, and temporary anchorage devices. Aligners were the least problematic. The treatment time was also prolonged. Telephonic advice and virtual assistance via WhatsApp messages/videos were found to be successful in the management of urgencies.Most orthodontists had strengthened their routine biosafety measures.The financial impact of this pandemic was considerable, with nearly 50% reduction in total income.
CONCLUSIONS
Urgencies linked to preadjusted edgewise appliances, such as breakage of brackets and tubes, and archwire-related injuries were the most common. Prolongation of treatment time and negative financial impact were the other problems encountered during this pandemic. Drastic changes had occurred in routine biosafety measures, which prevented the spread of infection among orthodontists and patients.
... The rates of stationary anchorage failure of miniscrews under orthodontic loading range between 11% and 30%, according to the literature [19][20][21][22] . A miniscrew that becomes loose won't regain its stability and will likely need to be taken out and replaced 23 . Bone density, peri-implant soft tissues, miniscrew design, surgical technique, and force load all affect how stable an orthodontic miniscrew will be during the course of therapy 14,24-28 . ...
In the last two decades, advances in digital and 3D printing technology, a rise in interest in cosmetic orthodontics, particularly among adults, and manufacturer marketing on a global scale have all contributed to clear aligners becoming a staple in modern orthodontic practise. Clear aligners have seen numerous improvements since they were first introduced with the goal of making orthodontic treatment less obvious. Like many other orthodontic tools, transparent aligners are used to move teeth for alignment and to create healthy, attractive smiles, but they are far more comfortable and aesthetically pleasing. The success of the treatment depends on the therapists' expertise and experience with the aligners, careful case selection, and patients' adherence to the prescribed treatment plans.
... Twenty years ago, orthodontic microscrews and miniplates were introduced as means to enhance anchorage [33][34][35]. With the introduction of such devises in treatment planning, the need for patient cooperation that was mandatory regarding conventional devices, was reduced. ...
The article presents a case of bimaxillary dentoalveolar protrusion treated by distalizing the upper and lower teeth, using anchorage from mini implants. A 16-year-old male patient presented with severe upper and lower incisor proclination with protruding lips and a convex profile, with a background of bimaxillary dentoalveolar protrusion. Instead of having four premolars extracted, retraction of the dentition was decided with absolute anchorage, provided by mini implants. In order to carry out the procedure in one stage, four mini-implants were inserted as close to the root of the 1st molars as possible. Implementation was facilitated by a surgical template which was created on a digital model and then 3D printed. Accurate placement was achieved and the case was successfully treated by significant uprighting of the incisors and retraction of the anterior dentition, closing the spaces in the upper and lower arch. Facial aesthetics were also improved. A digitally designed surgical guide was utilized in this case of bimaxillary dentoalveolar protrusion in order to facilitate the accurate placement of the mini implants which were used for a one-stage retraction of the dentition.
... Although all of these elements have different features, they all need a supporting structure, an orthodontic anchorage, to generate a force vector. Undesired complications can be seen if anchorage unit was not planned properly thus, anchorage planning was considered as the most important part of the orthodontic treatment planning (1)(2)(3)(4). ...
Orthodontic miniscrews are used for skeletal orthodontic anchorage. An appropriate insertion technique is essential to avoid complications during miniscrew placement. The guides prepared using surface anatomy and 2D radiographs cannot correctly analyze bone volume. Advances in digital 3D medical technologies enabled orthodontists to use digital imaging, digital scanning, and 3D printing to accurately place miniscrews using a surgical guide developed with computer-aided design and manufacturing techniques. The objective of this article was to demonstrate the development of miniscrew placement techniques chronologically and provide brief information about the production, use, and efficiency of modern, digitally planned, and produced miniscrew insertion guides.
... Similarly in lingual orthodontics, the introduction of the palatal implant made the mechanics easy as well as helps to solve the problem regarding palatal tipping and vertical bowing of the arch. [6][7][8] Palatal implant also reduces the chances of damaging the roots, periodontium, and also reduces the risk of implant fracture due to the larger dimension of the inter-radicular mini implant. 9 According to Ludwig et al 10 , the anterior palate, area around mid palatal raphae, and alveolus area between the second premolar and first molar is a more suitable insertion site for the placement of the palatal implant. ...
Introduction: The choice of orthodontic appliance depends upon the patients age, profession and availability of them. Lingual orthodontic appliances are preferred over labial by patients because of its invisibility. The aim of this research is to compare the Von Mises stress distribution and displacement of palatal implants in the lingual orthodontic system among four different combinations of palatal implant and lever arm. Materials and Method: Four Finite element models were constructed for the bilaterally extracted first premolar maxillary arch. In all these models 0.018" slot lingual brackets were placed at the center of the clinical crown. A similar retraction force (150gm) was applied with the help of NiTi closed coil spring for all the models but the length of the lever arm vary as well as the palatal implant position also varies in these models. Finite element analysis was then performed to compare the Von Mises stress distribution, and displacement of the palatal implant using ANSYS 12.1 software. Result: In this study, displacement was the same (0.0005 mm) for all four models. Highest amount von mises stress was observed in Model 3 (3.4798 MPa) as a comparison to Model 1 (2.5442 MPa), Model 2 (2.5018 MPa), and Model 4 (3.3854 MPa). The stress value for the palatal implant was within the acceptable fatigue limit of the titanium of 193 MPa therefore all four models combination was safe for the clinical application. Conclusion: Double palatal implant systems were more effective in comparison to the single palatal implant system in lingual orthodontics. In this study, we found that the displacement of the palatal implants was not affected by the length of the lever-arm and the amount of stress was decreased when we increase the length of the lever-arm.
... Finally, the more orthodontist is aware of biomechanical principles, the more he/she is successful in discerning the best plan of treatment and the best way to harness that plan [2][3][4][5][6][7][8][9][10][11][12]. ...
In this article, the authors discuss two preeminent notions in orthodontics; those are the approaches of “En Masse Retraction” and “Sequential Retraction” in orthodontic cases. The “Sequential Retraction” is identified by retraction of canines firstly, forming one group of retracted canine and posterior teeth in the respective side, then retraction of the incisors. Besides, the approach of “En Masse Retraction” is identified by retraction of the six anterior teeth “as one group”. Sequential Retraction is called “two-phased retraction”, whereas “En Masse Retraction” termed as “one-phased retraction”. Sequential Retraction has been justified for its characteristic of upholding anchorage, while En Masse Retraction is beneficial in keeping the alignment of the anterior teeth during treatment
... Os miniimplantes de titânio são indicados para casos onde se faz necessário um controle de ancoragem absoluto, ou seja, onde há alguma necessidade de ancoragem 10,[16][17][18]20 , mais especificamente, nos seguintes casos: (1) quando não haja cooperação adequada do paciente; (2) de perdas múltiplas; (3) que necessitem ancoragem máxima em pacientes onde o ângulo mandibular é alto, ou em jovens pacientes com tendência à rotação posterior da mandíbula; (4) intrusão de dentes extruídos (molares); (5) tratamento da mordida profunda anterior; (6) trespasse horizontal exagerado; e, (7) quando se deseja mesialização de molares (perda de ancoragem). Nos casos de molares extruídos, os mini-parafusos podem ser aplicados por vestibular e palatino 18 , ou pode-se também fazer uso de uma barra palatina no lugar do implante palatino (omplants). ...
Palavras-chave: Biomateriais; Ligas metálicas; Corrosão. RESUMO Este trabalho tem o objetivo de revisar a literatura sobre os materiais específicos para uso em Ortodontia, uma vez que o crescente volume de pesquisas clínicas e analítico-experimentais exige do profissional conhecimento atualizado. Dentre os materiais utilizados em Ortodontia existem materiais híbridos, onde diferentes classes podem coexistir resultando materiais mais elaborados, tais como: 1) metal-cerâmico; 2) metal-polímero; e, 3) polímero-cerâmico. Os biomateriais podem ainda ser compósitos reforçados com vidros cerâmicos. Neste trabalho são discutidos também os materiais metálicos, suas propriedades e aplicações, incluindo bráquetes, arcos e os miniparafusos de ancoragem temporária. ABSTRACT This work aims at revising the literature about the new biomaterials used specifically in orthodontics, once the rising number of clinical and analytic-experimental research demands that the professional have updated knowledge. Among the materials employed in orthodontics there are some hybrid materials, thus these materials can coexist resulting more elaborated materials such as 1) ceramic-metallic; 2) polymer-metallic and 3) ceramics-polymer. Biomaterials may also be composites reinforced with glass. In this work, we also mean to discuss metallic materials, their properties and applications including brackets, arches and the temporary anchorage systems. INTRODUÇÃO A aplicação dos materiais utiliza-dos é função de suas propriedades e de sua classificação em Ortodontia (me-tais, cerâmicos, polímeros), além de outros fatores. Hoje os materiais ortodônticos podem ser fabricados a partir da mistura de materiais de classes diferentes 13. Estes são classifica-dos como materiais compósitos, podendo ser: 1) compostos metal-cerâ-micos; 2) compostos metal-polímeros; e, 3) compostos polímero-cerâmicos. Podem ainda, ser compósitos reforça-dos com partículas de filamentos cerâmicos. Exemplos de compostos polímero-cerâmicos são os cerômeros e as resinas de nova geração do tipo Bis-GMA de Bowen, onde uma matriz polimérica é reforçada com partículas cerâmicas. Com o desenvolvimento dos polímeros estão sendo desenvol-vidos arcos ortodônticos poliméricos, conhecidos como fios "translúcidos" os quais são destinados a apresentar boa resistência à flexão, além do apelo estético. Existe ainda uma quinta clas-se de materiais, os semicondutores, atualmente utilizados nos aparelhos de fotopolimerização à base de diodos Ferreira, Marcelo do Amaral et al. Biomateriais em Ortodontia: características, aplicações e inovações
... It is well documented in the literature that if root contact occurs during the MSI insertion, the MSI should be removed and reinserted in a new location, 14 which is commonly performed by orthodontists without any clinical guidelines. 15 Chung et al 15 investigated the morphologic and mechanical characteristics of retrieved MSI that has penetrated human bone once and found varying degrees of notable MSI tip deformation. ...
Objective
The purpose of this study was to evaluate the insertion torque and dimensional changes of miniscrew implant (MSI) on root contact and the mechanical risk inherent in reinserting the same.
Materials and Methods
A total of 150 miniscrew implants were inserted to establish intentional root contact with freshly extracted premolar embedded in a synthetic bone block to evaluate the maximum insertion torque. Cone-beam computed tomography scans of bone blocks were done to confirm root contact. MSIs were retrieved after root contact and morphological changes in MSIs were evaluated using a scanning electron microscope. The insertion torque of retrieved MSI was again re-evaluated by reinserting it into a fresh bone block.
Results
The maximum insertion torque for the miniscrew implant on root contact was significant. The Dentos MSI showed significant dimensional changes on root contact followed by the Biomaterial and SK Surgicals MSI. The reinsertion torque of retrieved MSI after intentional root contact was highly significant.
Conclusions
The maximum insertion torque of MSI increased significantly with varying degree of deformation and blunting at the MSI tip and its threads on intentional root contact. Majority of retrieved MSI exhibited decreased cutting efficiency and a significant increase in reinsertion torque there by increasing the risk of mechanical failure.
... Furthermore, one of the most common complications reported during orthodontic micro-screws insertion is causing a trauma to the dental root and/or the periodontal ligament; specifically, when the trauma is limited to the outer dental root surface without pulp involvement, it is less probably to influence the prognosis of the tooth [32]; in addition, the periodontal ligament and the cementum have shown a complete reparation capacity between 12 and 18 weeks after the orthodontic micro-screws removal [33]. Moreover, when orthodontic micro-screws insertion comprises the periodontal ligament, the patient begins to experience stronger sensations under local anesthesia [15,34]. Furthermore, if there is contact with the root, the orthodontic micro-screws may require greater insertion strength [33]. ...
To analyze the effect of a computer-aided static navigation technique and mixed reality technology on the accuracy of orthodontic micro-screw placement. Material and methods: Two hundred and seven orthodontic micro-screws were placed using either a computer-aided static navigation technique (NAV), a mixed reality device (MR), or a conventional freehand technique (FHT). Accuracy across different dental sectors was also analyzed. CBCT and intraoral scans were taken both prior to and following orthodontic micro-screw placement. The deviation angle and horizontal deviation were then analyzed; these measurements were taken at the coronal entry point and apical endpoint between the planned and performed orthodontic micro-screws. In addition, any complications resulting from micro-screw placement, such as spot perforations, were also analyzed across all dental sectors. Results: The statistical analysis showed significant differences between study groups with regard to the coronal entry-point (p < 0.001). The NAV study group showed statistically significant differences from the FHT (p < 0.001) and MR study groups (p < 0.001) at the apical end-point (p < 0.001), and the FHT group found significant differences from the angular deviations of the NAV (p < 0.001) and MR study groups deviations (p = 0.0011). Different dental sectors also differed significantly. (p < 0.001) Additionally, twelve root perforations were observed in the FHT group, while there were no root perforations in the NAV group. Conclusions: Computer-aided static navigation technique enable more accurate orthodontic micro-screw placement and fewer intraoperative complications when compared with the mixed reality technology and conventional freehand techniques.
... This is in agreement with conclusions by Cheng et al., (2004), Berens et al., (2006), andWiechmann et al., (2007) who also reported a better prognosis for miniscrews located in the attached gingiva. Keratinized gingiva is thought to reduce the development of hypertrophic tissues and inflammation (Melsen and Verna, 2005), and (Miyawaki et al. 2003). ...
The purpose of this study was to investigate the stability of temporary anchorage devices, rate of bodily canine retraction and anchorage loss using miniscrews as a skeletal anchorage mean. The sample comprised twelve patients (3 males and 9 females, age range 17-28 years) who were scheduled for extraction of upper premolars. After leveling and alignment, a pilot drill was used and titanium miniscrews1.2-1.3 mm in diameter and 8 mm length were inserted into the buccal cortical bone between the maxillary second premolars and first molars on both sides. Immediate loading of miniscrews and immediate canine retraction after extraction was performed. The canines were retracted with nitinol springs extending from the canine brackets to the mini-implant. Force magnitude was initially 75 gf and increased to 150 gf after 3 weeks. Patients were seen at 3-week intervals until retraction was considered complete. Stability, gingival index around miniscrews, and patient comfort were rated. Retraction distance evaluated by measuring distance between cusp tip of maxillary canine to buccal cusp tip of maxillary second premolar. Pre and post-retraction panoramic x-rays were taken to categorize type of canine retraction. Pre and post-retraction cephalometric x-rays were superimposed for measuring the amount of anchorage loss. The results revealed a success rate of 87.5% of the miniscrews. 62.5% of miniscrews had healthy gingiva, and 12.5% were acutely inflamed. Bodily retraction of canines occurred only in 61.9% of the cases. Mean anchorage loss was 0.21 mm. The first interval had the lowest mean retraction distance. The mean rate of retraction was 0.39 mm per week. In conclusion, the TADs are stable absolute anchorage units that can be used for rapid canine retraction. Close relationship exists between implant loss and soft tissue health.
... Furthermore, one of the most common complication reported during orthodontic micro-screw insertion is causing a trauma to the dental root and/or the periodontal ligament; specifically, when the trauma is limited to the outer dental root surface without pulp involvement, it is less probably to influence the prognosis of the tooth [30]; in addition, the periodontal ligament and the cementum showed a complete reparation capacity between 12 and 18 weeks after the orthodontic micro-screw removal [31]. Moreover, when the orthodontic micro-screw insertion comprises the periodontal ligament, the patient begins to experience an increased sensation under local anesthesia [15,32]. Furthermore, if root contact occurs, the orthodontic micro-screws may require a greater insertion strength [31]. ...
To analyze the influence of the computer-aided static navigation technique on the accuracy of placement of orthodontic micro-screws. One hundred and thirty-eight orthodontic micro-screws were randomly assigned to the following study groups: Group A. orthodontic micro-screw placement using a computer-aided static navigation technique (n = 69); B. orthodontic micro-screw placement using the conventional freehand technique (n = 69). In addition, the accuracy in the canine–premolar, premolar and molar sectors was analyzed in each study group. Cone-beam computed tomography and intraoral scans were taken both prior and subsequent to orthodontic micro-screw placement. The images were then uploaded using a 3D implant planning software, where the deviation and horizontal angles were analyzed using a multivariate linear model. These measurements were taken at the coronal entry point and apical endpoint between the planned orthodontic micro-screws. In addition, any complications resulting from micro-screw placement, such as spot perforations, were also analyzed in all dental sectors. The statistical analysis showed significant differences between the two study groups with regard to the coronal entry-point, apical end-point (p < 0.001) and angular deviations (p < 0.001) between the computer-aided static navigation technique and freehand technique study groups. Moreover, statistically significant differences were showed between the different dental sectors (p < 0.001). Additionally, twelve root perforations were observed at the conventional free hand technique study group while there were no root perforations in the computer-aided static navigation technique study group. The results showed that the computer-aided static navigation technique enables a more accurate orthodontic micro-screw placement with less intraoperative complications when compared with the conventional freehand technique.
... [7] Miniscrews when placed in the alveolar mucosa may cause soft-tissue overgrowth due to the irritation caused by the movement of loose alveolar tissue that can cover the head and attachments, that is, coil spring, elastic chain of the miniscrew implant in a day, or couple of days after placing the implant. [8] It can be minimized by placing an elastic separator, wax pellet, or a healing abutment cap. [9] Chemical agents in the form of mouthwashes like chlorhexidine may also help in reducing overgrowth by their anti-inflammatory, antibacterial, and the ability to slow down epithelialization. ...
... 3. The application of contemporary biomechanics principia could support "one-phased retraction" approach ( Figure 1). As translation movement helps (in case of en masse retraction) in conserving the leveling and alignment of anterior teeth and in avoiding the high "moment-values" effects, (High moments may affect the anchorage units, as a reaction, to counteract the moments of the anteriors) [1][2][3][4][5]. Nonetheless, En Masse Retraction is not indicated in all cases, nor it is a panacea. ...
In this article, the author discuss two preeminent notions in orthodontics; those are the approaches of “En Masse Retraction” and “Sequential Retraction” in orthodontic cases.
The “Sequential Retraction” is identified by retraction of canines firstly, forming one group of retracted canine and posterior teeth in the respective side, then retraction of the incisors.
Besides, the approach of “En Masse Retraction” is identified by retraction of the six anterior teeth “as one group”.
Sequential Retraction is called “two-phased retraction”, whereas “En Masse Retraction” termed as “one-phased retraction”.
Sequential Retraction has been justified for its characteristic of upholding anchorage, while En Masse Retraction is beneficial in keeping the alignment of the anterior teeth during treatment.
Sequential Retraction has two phases: Firstly, canines are moved posteriorly, then canines are congregated with the posterior units of second premolars and first molars (in addition to second molars if they are banded) to form one group. Secondly, the anterior four incisors are retracted.
Sequential Retraction may cause temporary spaces especially in between lateral incisors and canines what are unwelcome sometimes.
In addition, in the first phase of sequential retraction, it is recommended that a “stop” on the mesial of the molar tube be placed (Tweed et al), to “maintain the anchorage” by preventing its “burning” (by a potential movement of the first molar mesially)(1). Nonetheless, this stop has its own reaction on the pertinent incisors, consequently the incisors move anteriorly little bit, in the canine retraction phase, what in turn, increases the burden on the anchorage units, during the “phase-two” of incisors retraction.
In other word, the conception that sequential retraction is more “harmless” towards the anchorage units is gradually becoming a debatable issue. Furthermore, an advantage of the “En Masse” retraction in maintaining the “Leveling of Alignment” of anterior teeth should be taken into account by clinician.
By applying the “theory of Optimal Force Values”, (which depends on using continuous low force, as minimal as available, and simultaneously over the due threshold that is sufficient to cause tooth movement), it is available to achieve canines and incisors “en masse” retracted without such an overload onto anchorage segments. As the standpoint would be to apply optimal forces on the anterior teeth, with least counteracted movements onto anchorage units proposing forces dissipation until be below the sufficient threshold for posterior teeth movement.
... incidences further increase in case of reduced cortical bone thickness (7)(8)(9)(10)(11)(12)(13)(14). The thickness of the bone can be studied with the help of cone-beam computed tomography (CBCT). ...
... 5 Placement of the mini implant should be in the keratinized gingiva as placement in nonkeratinized gingiva leads to formation of hypertrophic tissue formation and inflammation,leading to failure of the mini implant. 6,7 Success of orthodontic mini implant depends on root proximity of the screw, cortical bone thickness and placement angle. For prosthetic implants, 3mm between the adjacent root and implant surface is recommended for integration and proper health of the tooth. ...
Anchorage refers to the resistance against displacement by anatomical structures and the control of anchorage is one of the main factors for determining the success of orthodontic treatment. Conventional means of anchorage system were extra-oral and intra-oral anchorage. Evolution of intra-oral skeletal anchorage provided “Absolute Anchorage” using dental implants, miniplates and mini implant for fixed appliances which demanded stationary type of anchorage. Success of orthodontic mini implant depends on root proximity of the screw, cortical bone thickness and placement angle. In this article, we have described a grid for site selection and a well designed standard placement guide to prevent the root proximity while insertion, and reduce the chance of implant failure.
... The stress values in the cortical bone were minimum at 90° angulation and values at 60°, 75°, and 45° were in between. Previous studies have shown that cortex thickness primarily governs the transmission of force from mini-screw to bone, and cancellous bone thickness plays a minor role (34,35). More importantly, cortical bone is more resistant to distortion and can withstand higher loads mainly because of its higher modulus of elasticity. ...
Objective:
The objective of the study was to evaluate the stress pattern in cortical and cancellous bones, periodontal ligament, and in the implant itself when a mini-implant (MI) is inserted in the inter-radicular space between mandibular first molar and second premolar at various angulations and different retraction forces.
Methods:
Finite element study was conducted with MI insertion at 30°, 45°, 60°, 75°, and 90° angulations in the mandibular posterior region (between second premolar and first molar). At these angulations, horizontal forces of 150, 200, and 250 g were applied to the middle of the MI head. von Mises stress values were then evaluated using the ANSYS software.
Results:
Highest von Mises stress values were detected in the MI itself, followed by cortical bone, cancellous bone, and periodontal ligament. The von Mises stress values in cortical bone were highest at 30° angulation and lowest at 90° angulation. In the cancellous bone, the stress value was found to be maximum at 90°. The von Mises stress values in the MI were lowest at 90°. In all four structures, as the load increased from 150 to 250 g, the von Mises stress values increased.
Conclusion:
The von Mises stress values in the cortical bone, MI, and periodontal ligament were found to be lowest at 90°. Placement of the MI at 90° appears to be an ideal angulation when applied with a horizontal load. Force range used is within clinically recommended levels; however, the increase in load causes an increase in the stress values.
... In cases where there is a class I relationship in the extracted cases; Jarabak, used intraoral elastics in the closure of the extraction space and intermaxillary elastic in the presence of a class II relationship, and took care that the elastic force is not more than 113.6 gr (14).The amount of force recommended in the literature for the en-masse retraction ranges from 150-300 gr. It has been reported that this amount of force is sufficient to cover the space of 0.5 mm -1 mm (15). The amount of force that can be applied with mini implants is between avarage 200-400 gr. ...
Treatment of skeletal Class II malocclusions is difficult anomalies in orthodontics. The treatment of skeletal Class II anomalies varies according to the jaw and the growth period of the anomalies. Adult individuals whose growth is over are treated with fixed orthodontic mechanics or orthognathic surgical approaches. If skeletal class II anomaly is not severe and does not constitute a problem aesthetically, camouflage treatment can be done with fixed orthodontic mechanics. This case report presents the results of orthodontic camouflage treatment and treatment applied to a skeletal Class II malocclusion female patient with chronological age of 18 years and skeletally in the Ru period. The molar relationship of the patient with a slightly convex profile is Angle Class II. In cephalometric examination, skeletal class II problem was detected (ANBº = 6º). At the end of the treatment, angle class II relation in the molar region, angle class I relation in the canine region and a smooth soft tissue profile were obtained.
... 5 A lack of primary stability can often be attributed to low bone density or low bone stock at the placement site. 6 With the modest failure rate and a rising demand for mini-implants in day-to-day clinical orthodontics, a thorough understanding of the associations between mini-implant failure and the associated tissue factors is highly warranted. By determining optimal placement sites and any associated factors, clinicians will be able to design their treatment plans accordingly and utilize these devices with a higher success rate. ...
Objective:
The primary objective of this study was to quantitatively analyze the bone parameters (thickness and density) at four different interdental areas from the distal region of the canine to the mesial region of the second molar in the maxilla and the mandible. The secondary aim was to compare and contrast the bone parameters at these specific locations in terms of sex, growth status, and facial type.
Methods:
This retrospective cone-beam computed tomography (CBCT) study reviewed 290 CBCT images of patients seeking orthodontic treatment. Cortical bone thickness in millimeters (mm) and density in pixel intensity value were measured for the regions (1) between the canine and first premolar, (2) between the first and second premolars, (3) between the second premolar and first molar, and (4) between the first and second molars. At each location, the bone thickness and density were measured at distances of 2, 6, and 10 mm from the alveolar crest.
Results:
The sex comparison (male vs. female) in cortical bone thickness showed no significant difference (p > 0.001). The bone density in growing subjects was significantly (p < 0.001) lower than that in non-growing subjects for most locations. There was no significant difference (p > 0.001) in bone parameters in relation to facial pattern in the maxilla and mandible for most sites.
Conclusions:
There was no significant sex-related difference in cortical bone thickness. The buccal cortical bone density was higher in females than in males. Bone parameters were similar for subjects with hyperdivergent, hypodivergent, and normodivergent facial patterns.
... After the use of dental implants in dentistry for prosthetic purposes, the idea that this application can be used for orthodontic anchorage was proposed [1]. Miniscrews developed for this purpose started to be used dentistry after the 1970s [2]. ...
The aim of this retrospective study is to present a guide for the clinicians by detecting the best mini screw placement areas with the measurement of cortical bone thickness in the patients who have cone beam computed tomography (CBCT) images. Additionally to be protected from root damage and a potential damage to environmental anatomic tissues, related measurements will also be held in the determined areas.This study has been evaluated by using the images of 52 patients taken by cone beam computed tomography for diagnosis and cure.In the mandibular measurements which were done by using CBCT, the buccal cortical bone thickness has been found out to increase while going towards the posterior region and going down to the apical region at the same area. In addition, it was observed mostly between second premolar and first molar teeth at the farthest area from the top of the crest, along the mandibular canal. The distance between base of the nose and maxillar sinus floor to the hill of the crest has also been observed that decreased towards the posterior region.Although it can vary according to the person, in mini screw applications, mandibular cortical bone structure and the interradicular range is more suitable than the upper jaw. To be protected from the potential complications and for a better stability, radiologic analysis is recommended to the patient before the mini screw placement.
... Algunos autores han reportado el uso de estos anclajes para la intrusión de molares (10)(11)(12). se han reportado varios sistemas de Mini-Implantes que permiten el anclaje absoluto para movimientos de ortodoncia (13)(14)(15)(16). ...
In this case report, a miniimplant system that uses vestibular and palatal screws is presented as an excellent alternative forthe treatment of and open bite case, it’s thru molar intrusion without any undesired transversaleffect that the final results were achieved. The main topics treated are: diagnostic, treatmentplan, surgical protocol, anatomic considerations, possible complications, curse of treatment, andfinal presentation of the case. Key words: Intrusion. Open bite. Temporal anchorage devices(TAD).
... Stationary anchorage failure often results from low bone density due to inadequate cortical thickness. 29 The primary implant stability of an OMI can be estimated by computed tomography measurements of cortical bone thickness and trabecular bone density before treatment. 30 In conclusion, the primary stability of an OMI depends on both cortical bone thickness and trabecular bone density. ...
Background/purpose:
Mini-implant screws are now routinely used as anchorage devices in orthodontic treatments. This study used synthetic bone models to investigate how the primary stability of an orthodontic mini-implant (OMI) as measured by resonance frequency (RF) is affected by varying cortical bone thickness and trabecular bone density.
Materials and methods:
Three synthetic cortical shells (thicknesses of 1, 2, and 3 mm) and three polyurethane foam blocks (densities of 40, 20, and 10 pound/cubic foot) were used to represent jawbones of varying cortical bone thicknesses and varying trabecular bone densities. Twenty-five stainless steel OMIs (2 × 10 mm) were sequentially inserted into artificial bone blocks to depths of 2, 4, and 6 mm. Five experimental groups of bone blocks with OMIs were examined by Implomates® RF analyzer. Statistical and correlation analyses were performed by Kruskal-Wallis test, Wilcoxon rank-sum test, and simple linear regression.
Results:
As trabecular bone density decreased, RF decreased; as cortical bone thickness decreased, RF also decreased. Simple linear regression analysis showed highly linear correlations between trabecular bone density and RF (R2 > 0.99; P < 0.0001) and between cortical bone thickness and RF (R2 > 0.98; P < 0.0001).
Conclusion:
The stability of an OMI at the time of placement is influenced by both cortical bone thickness and trabecular bone density. Both cortical bone thickness and trabecular bone density have strong linear correlations with RF.
... One of the greatest limitations in modern orthodontic treatment is Tooth borne anchorage. This is mainly due to the tooth movement in response to orthodontic tooth movement 1 . ...
Anchorage control during active orthodontic treatment is essential for uncompromised results. Conventional method of supporting anchorage have been using either tooth borne anchorage or extra oral anchorage. Extra oral anchorage can be used to supplement tooth borne anchorage and to deliver forces in directions not possible with intra oral forces but requires excellent patient co-operation. Intra-oral skeletal anchor units that are predictably stable,non-invasive, biocompatible and comfortable could make appliance design simplified and more efficient. With the introduction of Mini implants and microimplants they can be placed in areas earlier impossible. They are less expensive, allowing early force application and with reduced treatment time. The presently available implant systems are bound to change and evolve into more patient friendly and operator convenient designs. Long-term clinical trials are awaited to establish clinical guidelines in using implants for both orthodontic and orthopedic anchorage. The objective of this article is to review the types of min-implants depending on the loading time, placement and insertion of min-implants, complications associated with and to formulate a definite clinical protocol for loading of orthodontic mini implants. It also deals with the future scope of min-implants usage during active orthodontic treatment. © 2018, Indian Journal of Public Health Research and Development. All rights reserved.
... Algunos autores han reportado el uso de estos anclajes para la intrusión de molares (10)(11)(12). se han reportado varios sistemas de Mini-Implantes que permiten el anclaje absoluto para movimientos de ortodoncia (13)(14)(15)(16). ...
In this case report, a mini implant system
that uses vestibular and palatal screws is
presented as an excellent alternative for
the treatment of and open bite case, it’s
thru molar intrusion without any undesired
transversal effect that the final results were
achieved.
The main topics treated are: diagnostic,
treatment plan, surgical protocol, anatomic
considerations, possible complications,
curse of treatment, and final presentation
of the case.
... Special attention was given to preserving the integrity of the periosteal membrane during the entire intervention to be joined at the end of the procedure by the means of internal resorbable sutures. The MS placement procedure was the same as that described by Melsen and Verna (32), who recommended manual insertion with a custom screwdriver (Aarhus anchorage system octagonal screwdriver, Medicon®, Germany) and the need of creating a pilot hole in sites with thick cortical bone (32). This pilot hole has been modified in our study to suit the dimensions of the SMS design and the delivery of iBGS. ...
Objective:
The aim of this study was to assess the potential of improving orthodontic miniscrews' (MSs) primary stability in vivo by evaluating the dispersion capacity of an injectable bone graft substitute (iBGS) through a newly designed hollow MS [The Sydney Mini Screw (SMS)] and its integration with the cortical and trabecular bone by using the femur and tibia in a New Zealand rabbit animal model.
Methods:
In total, 24 MSs were randomly placed in each proximal tibia and femur of 6 New Zealand rabbits with an open surgery process. Aarhus MSs were used as controls and the effect of injection of iBGS was studied by implanting SMSs with and without iBGS injection. The dispersion of iBGS and the integration of the SMS were studied by using micro Computed Tomography (μCT) and histochemical analysis at two time points, 0 day and 8 weeks post-implantation.
Results:
iBGS was successfully injected through the SMS and hardened in situ. After 8 weeks, μCT results revealed that the iBGS particles were resorbed and bone tissue was formed around the SMS and within its lateral exit holes.
Conclusions:
This pilot animal study showed the high potential of the combined use of iBGS and SMS as a newly developed technique to promote the primary stability of MSs.
... Because excessive strain levels might lead to screw loosening in areas with thin cortical bone and low density trabecular bone, it was recommended to start with forces of 50g and increase them after initial healing. [31][32][33][34] Liou et al 34 found significant screw displacements after applying immediate forces of 400g. However, a study using the same protocol correlated screw displacement to the duration and not to the direction or magnitude of forces of 200 to 425g. ...
This study investigated the effect of diameter on stability of mini-screws used as skeletal anchorage for maxillary canine retraction utilizing two different force magnitudes. Findings revealed that increasing the diameter of the mini-screws increases their stability. However, utilization of a high retraction force negatively affects stability especially with small diameters mini-screws.
... Cortical bone quantity and quality affect long-term stability. Stationary anchorage failure is often caused by low bone density or inadequate cortical bone thickness (14). Cortical bone thickness is important in the success of an MSI because insufficient cortical bone thickness often causes inadequate primary Table 3 Resonance frequency values for T0, T1, T2, T3, T4, stability. ...
This study used resonance frequency (RF) analysis to assess miniscrew implant (MSI) stability during wound healing in a sample of 68 patients (41 women, 27 men; mean age, 27.7 years). The 104 MSIs included 66 placements in the buccal shelf (BS; 2.0 × 12 mm) and 38 placements in interradicular (IR; 1.5 × 8 mm) sites. Thirteen (12.5%) of the MSIs failed. A new RF detection device was used to measure RF at baseline (T0) and at 3 (T1), 6 (T2), 9 (T3), 12 (T4), and 15 (T5) weeks after placement. A linear mixed-effects model was fitted to change in RF values. As compared with the BS group, the IR group had significantly lower RF values on the right side from T0 through T4 and on the left side from T0 through T2. Insertion site and time of visit were significantly associated with RF value. The effects of time of visit significantly differed between the BS and IR sites. Starting from T0, the MSIs placed at both sites had significantly lower RF values at all intervals, except for T0-T1. Future studies should examine how the present clinical protocols can optimize timing of MSI loading to maximize the success rate.
... The transpalatal arch was placed and a three-piece intrusion arch fabricated for simultaneous intrusion and retraction. A nickel-titanium coil spring or elastic chain was attached between the distal extension of the anterior segment and the mini-screw to initiate anterior retraction ( Figure 3) [6][7][8][9][10]. ...
In the last decade of the preceding century, orthodontic practice witnessed the reporting of periodontal ligament distraction for rapid canine retraction1, the use of mini screws for anchorage 2-9, and the resurrection and refinement of corticotomy –facilitated orthodontics 10-15. These methods added aspects of strength to routine clinical practice. It has been hypothesized that, by “amalgamating” conventional fixed orthodontic treatment with the aforementioned techniques, it would be possible to produce a “layered” treatment regimen that maximizes the patients’ benefit. The advantages of the new techniques should theoretically cancel out the drawbacks of routine fixed treatment (long duration, enamel lesions, root resorption, anchorage problems). This article describes the evolution and clinical application of a new technique, The Amalgamated Technique
REVISÃO DE LITERATURA RESUMO A ancoragem esquelética com o uso de mini-implantes revolucionou o controle de ancoragem na ortodontia, oferecendo uma alternativa mais eficaz e previsível em relação às mecânicas tradicionais que dependem de aparelhos extrabucais e elásticos intermaxilares. Esse método tem se mostrado particularmente vantajoso, pois reduz ou elimina a necessidade de colaboração do paciente, acelerando o tratamento e garantindo maior precisão nos movimentos dentários. Durante a fase de retração anterior, etapa crucial do tratamento ortodôntico, os mini-implantes permitem que o ortodontista alcance objetivos fundamentais, como a chave de caninos e molares, a correção da sobremordida e a coincidência das linhas médias, de forma mais controlada e eficiente. Além disso, sua instalação e ativação imediatas minimizam o tempo de espera, otimizando a duração total do tratamento. Este artigo revisa os avanços no uso de mini-implantes, destacando suas principais aplicações clínicas e os benefícios proporcionados em termos de previsibilidade e controle de ancoragem.
During orthodontic treatment, undesirable reciprocal forces are generated during tooth movement, which explains the use of anchorage strategies to minimise their harmful effects through intra and/or extraoral appliances. Miniscrews are intraoral devices used for temporary skeletal anchorage. Miniscrews are small‐sized intraoral devices used for temporary skeletal anchorage and are easy to place and remove. However, some studies refer to adverse effects such as inflammation, pain, and discomfort. This systematic review aims to synthesise the available evidence on the use of miniscrews during orthodontic treatment from the patient's perspective. The literature search was conducted using various databases MedLine through PubMed, Cochrane Library, Web of Science Core Collection, and EMBASE. A search was also carried out in the grey literature. The search terms used were “Orthodontic Anchorage Procedures,” “mini‐implant,” “Mini Dental Implant,” “Miniscrew,” and “microimplant.” Cochrane risk of bias tools was used to assess the quality of included studies. Patients tend to overestimate the pain inherent in this procedure. The insertion of micro implants is more accepted than the tooth extraction procedure, with less postoperative pain reported. The location, surgical technique, and type of anaesthesia used in the placement of miniscrews influence levels of discomfort. Additionally, the execution of a good surgical technique and the clinician's communication skills are factors that influence patient satisfaction and positive perception. The most frequent outcome reported is pain and discomfort, which varies depending on its location (less with mini interradicular screws than with extra‐alveolar screws). Most patients are satisfied or very satisfied with this application.
Miniscrews are temporary skeletal anchorage devices that are widely used in orthodontic treatment, and their success depends on the placement area, angle, technique, and screw dimensions. This study aimed to investigate the effects of miniscrew lengths, insertion angles, and force directions on a mandible model consisting of teeth, cortical and cancellous bones. One Dental Volumetric Tomography (DVT) scan from a patient who had miniscrews were used for mandibular bone modeling to perform finite element analysis. The model variables included miniscrew lengths (6, 8, and 10 mm), insertion angles (-15°, 45°, 60°, and 90°), and force directions (30°, 45°, and 60°). The minimum and maximum stresses were calculated as 18.61 and 37.11 MPa at 6 mm and 10 mm, respectively. According to the insertion angles, the lowest stress was observed at 60°, while the highest stress was found at 15° in the ventral direction. At force directions, the lowest stress was at 60°, and the highest stress was at 45°. However, there were no significant differences in insertion angles and force directions. A statistically significant difference was determined in miniscrew length. As a result, the best result was calculated to be 6 mm inserted at a 60° angle, which could induce the lowest stress. Increasing the miniscrew length will increase the stress on the mandible. In addition, because of the higher force direction, stress decreases with shorter power arms.
Ortognatik Tedavi ve Kök Rezorpsiyonu Merve Ece ERDEM Celal IRGIN Ortodonti ve 3 Boyutlu Stereofotogrametri Berna EVRENOL Sanaz SADRY Ortodontide Dijital Teknolojiler Rumeysa BİLİCİ GEÇER Sanaz SADRY Temporomandibular Eklem Problemlerinin Tedavisinde Genel Yaklaşımlar Kısım 1: Kesin Tedavi Yaklaşımları Cansu DÜZGÜN Temporomandibular Eklem Problemlerinin Tedavisinde Genel Yaklaşımlar Kısım 2: Destekleyici Tedavi Yaklaşımları Cansu DÜZGÜN Extraalveolar Mini İmplantların Ortodontide Kullanımı Fatih ATABAY Yazgı AY ÜNÜVAR Sınıf II Maloklüzyonların Fonksiyonel Tedavileri Özge ÜNLÜOĞLU Yazgı AY ÜNÜVAR Ortodontide Şeffaf Plaklara Genel Bakış Pervin BİLGİNER
When treating an adult patient, orthodontics will, in the majority of cases, be only part of the patient’s need for dental treatment. In the presence of a malocclusion, orthodontics is a necessary component of the total treatment, which involves collaboration between different specialities. The approach to the treatment may be multidisciplinary or interdisciplinary. The procedures involved when treating adult patients with a deteriorating dentition can be divided into two categories: essential and optional procedures. During the orthodontic treatment phase, it is important that patients are able to maintain perfect oral hygiene. Following the orthodontic treatment phase, further periodontal surgery may be needed before prosthodontic rehabilitation can be done. The patient’s satisfaction is related to the level of information provided. It depends on how well the discrepancy between treatment need and treatment demand has been resolved before initiating treatment.
Introduction
The clinical success of orthodontic miniscrew implants may be improved after pre-drilling a pilot hole. However, the amount of microdamage to the bone surface produced by the pilot hole is largely unknown. The present study aimed to quantify the damage to cortical bone after the creation of a pilot hole.
Materials and methods
Porcine tibia bone was prepared into 30 rectangular bone block specimens with widths of 1.5, 2.0 or 2.5 mm. A pilot hole (0.9 mm diameter) was drilled into each bone specimen. Sequential staining allowed the microdamage on the entry and exit surfaces to be imaged by a confocal laser scanning microscope. Image analysis software was used to measure histomorphometric parameters.
Results
The specimens had a mean total damage area of 0.95 mm ² , a maximum damage radius of 0.66 mm and a maximum crack length of 0.18 mm. There were no significant differences between the three bone thicknesses for any of the histomorphometric parameters on the entry and exit surfaces ( p > 0.05). The total damage area was significantly greater on the exit surface compared to the entry surface ( p < 0.0001).
Conclusions
Microdamage caused by the creation of a pilot hole in the cortical bone was minimal and did not appear to be influenced by bone thickness. Therefore, pilot hole pre-drill protocols may be implemented without introducing significant cortical bone microdamage.
Objective: The aim of this clinical trial study was to compare the clinical effects of maxillary incisors intrusion with miniscrews and burstone intrusive arch.
Methods & Materials: seventeen patients with a deep bite were divided to two groups. In first group, eight patients (thirty two incisal maxillary tooth) in the postpubertal growth period were treated by using miniscrew; in another group, nine patients (thirty six incisal maxillary tooth) were treated by using burstone intrusive arches. Ultra Low Dose CBCTs were taken at the beginning of treatment, after intrusion and after three month retention, for the evaluation of the treatment changes. Statistical analyses of the data were performed with a significance level of P<2/26.
Results: The amount of intrusion in all three time periods in the mini-screw group was significantly higher than the Burstone group. The rate of active intrusion was significantly higher in the mini-screw group than in the Burstone group. No statistical differences were found in the reduction of overbite between the two groups in the active intrusion phase. Some relapse was seen in the Burstone group, but no relapse was seen in the mini-screw group.
No clinically significant differences were found in periodontal criteria between the two groups.
The reduction in gingival display was significantly greater in the mini-screw intrusion than in the Burstone intrusion.
Conclusion: Both the mini screw and the Burston intrusion arches methods are effective in intrusion of upper incisors. Mini screw gives more true intrusion and decrease more gingival display. Vertical relaps was not seen in miniscrew method.
Keywords: Intrusion, Burstone intrusive arch, miniscrew
La gestion de l’ancrage est un paramètre clé dans le succès des thérapeutiques orthodontiques. Parmi les nombreux systèmes classiquement décris, tels que les forces extra-orales, les pastilles de Nance, ou encore le ten-two system de Tweed, aucun n’est dénué d’effets indésirables. C’est pourquoi des dispositifs dits « d’ancrage absolu », sans appui dentaire et permettant de s’affranchir de la coopération du patient sont apparus. Ils sont représentés par l’ensemble des vis ou mini-implants à visée orthodontique.
Nous proposons d’étudier ici deux de ces dispositifs : les mini plaques d’ancrage d’une part et les minivis OBS décrites par Chris Chang d’autre part. Notre propos sera illustré au travers de deux cas cliniques traités par distalisation molaire. Nous verrons que ces deux systèmes sont des ancrages osseux temporaires dont la polyvalence rend possible les déplacements des dents dans les trois dimensions de l’espace. Nous montrerons cependant que la phase chirurgicale est plus simple avec les minivis OBS avec moins de comorbidités associées.
Introduction: Abalakov is a mountaineering technique consisting in drilling two holes that intersect to form a V in order to thread a rope through to make an anchorage point. This technique can be applied to orthodontic treatment and constitutes a posterior mandibular orthodontic anchorage.
Technical note: the technique can be performed on its own during local anaesthesia or during surgery for the extraction of wisdom teeth. The posterior anchorage point is located in the ramus of the mandible. It consists in drilling two holes that intersect to form a V and then threading a steel wire through to make an anchorage point.
Discussion: this technique is simple, inexpensive, fast and non-invasive, providing an anchorage system with immediate loading and which is not dependent on the quality of the bone.
Biomechanical influences on bone structure play an important role in the longevity of bone around an implant. The quantity and direction of applied force influence the implant and cause deformation of the bone. FEA was used to analyze the changes in the bone on loading the implant with orthodontic force in oblique and vertical directions and orthopedic force. The Mini-implants used in the present study efficiently resisted the oblique loading. But their use, for the purpose of orthopedic loading is questionable. FE models showed the area with the highest stress and strain to be around the neck of the implant and the surrounding bone at the cervical margin.
To determine ideal sites for the placement of temporary anchorage devices (TADs), the depths of the hard and soft tissues of the oral cavity were evaluated in 20 patients. The bone depth was quantified by volumetric computed tomography (VCT). The mucosal depth was quantified by a needle with a rubber stop. The results indicate that bone thickness will allow TADs 10 mm in length only in the symphysis, retromolar, and palatal premaxillary regions. TADs 6 to 8 mm in length can be placed in the incisive fossa, in the upper and lower canine fossae. These TADs (4–5 mm) only engage monocortically, whereas the others have the ability to engage bicortically. When placing TADs in mobile alveolar mucosa, the results suggest that a transmucosal attachment may be required to traverse the thickness of the soft tissue.
The outcome of orthodontic treatment is often compromised by the loss of anchorage. Yet surprisingly, forces acting on the anchorage unit that bring about the loss have received very little interest. This paper discusses the biologic background for anchorage control; specifically, the impact of the orthodontic force systems and of occlusal forces on the cellular responses of periodontal tissues supporting the anchorage teeth. Also discussed is the influence of various anchorage devices on the interaction between vertical and sagittal directions of dentofacial development. The importance of taking the vertical forces into consideration is stressed. A rational approach to orthodontic anchorage is suggested. We advocate the use of intra-oral and extra-dental devices when possible, as well as rigid appliances that stimulate the patient's sensation of occlusion. Clinical cases are presented to demonstrate the clinical application of this new approach.
The aim of this study was to investigate experimentally the effect of long-term orthodontic loading on the activity and location of osteodynamic changes around short titanium screw implants. For this purpose 6 maxillary premolars (1P1,2P2,3P3) were extracted from each of 2 foxhounds. After a 16-week healing period, 8 implants (4 per dog) were inserted in the edentulous areas. Simultaneously 2 implants (1 per dog) were positioned in the palatal suture. After an 8-week implant healing period the fixtures in the P1/P2 areas (n=4) and the palate (n=2) were loaded (test implants) by means of Sentalloy traction springs (∼ 2N continuous force). The fixtures in the P2/P3 areas served as controls (n=4). The osteodynamic changes during the force application period (26 weeks) were recorded with bone labeling flourochromes.
Histological evaluation revealed a tendency towards higher remodeling activity within the peri-implant bone (up to 500 μm from the implant surface) of the loaded compared with the unloaded sample. This higher activity was found on both sides facing the loading direction as well as on the opposite sides. Furthermore, within the bone adjacent to the marginal halves of the implants on the loading direction sides, this higher remodeling activity extended more than 1000 μm from the respective implant surfaces.
The results suggest that long-term orthodontic loading of short macillary implants may increase the remodeling activity within the peri-implant bone.
Clinical rigidity ("osseointegration") was achieved by 94 percent of the titanium implants placed in dog mandibles. All loaded implants remained rigid. Inadvertent impingement on the periodontal ligament and roots of adjacent teeth was uneventful. Microradiographic imaging was more reliable than polarized light microscopy for assessing bone contact at the endosseous interface. Implants with less than 10 percent of the endosseous interface in direct contact with bone successfully resisted a continuous load of 3 N (greater than 300 grams) for 13 weeks.
Basic Multicellular Unit-based bone remodeling can lead to the removal or conservation of bone, but cannot add to it. Decreased mechanical usage (MU) and acute disuse result in loss of bone next to marrow; normal and hypervigorous MU result in bone conservation. Bone modeling by resorption and formation drifts can add bone and reshape the trabeculae and cortex to strengthen them but collectively they do not remove bone. Hypervigorous MU turns this modeling on, and its architectural effects then lower typical peak bone strains caused by future loads of the same kind to a threshold range. Decreased and normal MU leave this modeling off. Where typical peak bone strains stay below a 50 microstrain region (the MESr) the largest disuse effects on remodeling occur. Larger strains depress it and make it conserve existing bone. Strains above a 1500 microstrain region (the MESm) tend to turn lamellar bone modeling drifts on. By adding to, reshaping and strengthening bone, those drifts reduce future strains under the same mechanical loads towards that strain region. Strains above a 3000 microstrain region (the MESp) can turn woven bone drifts on to suppress local lamellar drifts but can strengthen bone faster than lamellar drifts can. Such strains also increase bone microdamage and the remodeling that normally repairs it. Those values compare to bone's fracture strain of about 25,000 microstrain.
Three finite element models were created to investigate the potential of rigid osseous fixation (osseointegration) for orthodontic anchorage: a mandible without an implant; a mandible with an implant; and a mandible and implant with a superimposed orthodontic load. Force was applied to different locations and the stresses were computed. The mechanical stress distributions adjacent to the implant were not affected by different biting forces, hence only one case needed to be analyzed. The stresses adjacent to the bone-implant interface changed drastically due to implantation, with major changes occurring on the buccal and mesiobuccal sides. A strong, concordant gradient for intraosseous stress and bone remodeling rate was observed that reflects a mismatch in the moduli of elasticity between the implant and the supporting bone. These results suggest important clinical implications. Osseointegration of symmetrically threaded titanium implants appears to be maintained by a sustained elevation of the mechanical stresses that continuously stimulate the bone remodeling activity within 1 mm of the implant surface. It is unlikely that a rigidly fixed (osseointegrated) implant will lose integration due to an orthodontic load superimposed on normal function.
The problems related to anchorage for orthodontic tooth movements in patients with deficient dentition are discussed, and various solutions suggested in the literature, including "onplants," implants, and zygoma wires, are evaluated. A miniscrew is presented as alternative anchorage, and possible locations for placement are discussed, based on studies of bone quality in dry skulls. Application of the miniscrew as anchorage for various types of tooth movement is demonstrated. Miniscrews are easily placed and removed and can be loaded immediately following insertion. However, stability is limited after loading with torsion.
A 3-dimensional bone-implant finite element model was created. The objective was to further investigate the mechanical environment of cortical bone adjacent to the threads of a retromolar endosseous implant used for orthodontic anchorage to mesially translate mandibular molars in response to normal functional loading. This study emphasizes the stress invariants around and between the threads of the implant for future comparison to histomorphometric data from an ongoing clinical study. A strong stress pattern change was found immediately around the implant, which was reflected by a moderate change of stresses between the threads and a significant increase in stress at the tips of the threads.
The aim of this study was to investigate experimentally the effect of long-term orthodontic loading on the activity and location of osteodynamic changes around short titanium screw implants. For this purpose 6 maxillary premolars (1P1, 2P2, 3P3) were extracted from each of 2 foxhounds. After a 16-week healing period, 8 implants (4 per dog) were inserted in the edentulous areas. Simultaneously 2 implants (1 per dog) were positioned in the palatal suture. After an 8-week implant healing period the fixtures in the P1/P2 areas (n = 4) and the palate (n = 2) were loaded (test implants) by means of Sentalloy traction springs (approximately 2 N continuous force). The fixtures in the P2/P3 areas served as controls (n = 4). The osteodynamic changes during the force application period (26 weeks) were recorded with bone labeling fluorochromes. Histological evaluation revealed a tendency towards higher remodeling activity within the peri-implant bone (up to 500 microns from the implant surface) of the loaded compared with the unloaded sample. This higher activity was found on both sides facing the loading direction as well as on the opposite sides. Furthermore, within the bone adjacent to the marginal halves of the implants on the loading direction sides, this higher remodeling activity extended more than 1000 microns from the respective implant surfaces. The results suggest that long-term orthodontic loading of short maxillary implants may increase the remodeling activity within the peri-implant bone.
The healing around an immediately loaded screw was described and related to the bone type, manner of loading and observation time. In four adult macaca fasicularis monkeys, 16 titanium vanadium screws were inserted into the infrazygomatic crest and two in the symphysis region. Immediately after insertion, screws were loaded with 25- and 50-g Sentalloy springs extending to the canines. Following an observation period of 1, 2, 4 and 6 months, the screws and the surrounding bone were removed. Undecalcified serial sections perpendicular to the long axis were made and the degree of osseointegration studied. Two of the screws were lost immediately after insertion. Of the remaining screws, osseointegration was present around all, but two. The integration was independent of bone type, trabecular or cortical, but increased with time. Based on the results of this study, the use of screws described in the report can be recommended as anchorage units in cases where conventional anchorage is not possible.
The aim of this study was to evaluate intramaxillary molar movement after 8 months of cervical traction and posttreatment displacement 7 years later. The total molar displacements in relation to stable intraosseous reference points were compared with those observed in an untreated control group that also had intraosseous reference indicators inserted. During the headgear period, the type of molar displacement could be predicted by the direction of the force system acting on the teeth. It was noted, however, that the variation in the vertical development was related more to each patient's growth pattern than to the force system applied. After cessation of the headgear, intramaxillary displacement of the molars was noted, and the total displacement of the molars did not differ from that of the untreated group. The indication for intramaxillary displacement of the molars by means of extraoral traction is therefore questioned.
Esthetics in orthodontics
- Fontenelle
Temporary anchorage devices in orthodontics
- Costa
Mini screws as orthodontic anchorage
- Costa