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Abstract

Background: Different designs of surgical drilling systems have been developed for the purpose of static Computer-Assisted Implant Surgery (sCAIS), but there is at present little understanding of how design principles affect the accuracy of implant placement. Purpose: The aim of this in vitro study was to compare the accuracy of implant placement among five drilling systems of sCAIS in a controlled experimental setting. Materials and methods: Twenty-five 3D printed models with two edentulous bilateral premolar spaces were allocated to five different drilling systems: group A: sleeve-in-sleeve, group B: sleeve-in-sleeve with self-locking, group C: mounted sleeve-on-drill, group D: integrated sleeve-on-drill with metal sleeve in the guide, group E: integrated sleeve-on-drill without metal sleeve. Models were scanned with CBCT and optical scanner. All implants were digitally planned and 10 implants placed with sCAIS in each group. Postoperative 3D deviation of placed vs planned position was measured by means of platform, apex and angular deviation. Data was analyzed using Kruskal-Wallis test (P ≤ .05). Pairwise comparisons were tested with Dunn's test with adjusted P values. Results: The overall platform deviation ranged from 0.42 ± 0.12 mm (group B) to 1.18 ± 0.19 mm (group C). The overall apex deviation ranged from 0.76 ± 0.22 mm (group B) to 1.95 ± 0.48 mm (group D). The overall angular deviation ranged from 2.50 ± 0.89 degree (group B) to 5.30 ± 1.04 degree (group E). Group A and B showed significantly less angular deviation than groups D and E (P < .05). There was no statistically significant differences in all parameters between group A and B, as well as between group D and E (P > .05). Conclusions: Significant differences were found with regards to accuracy among the five sCAIS systems tested, suggesting that the drilling protocol, the devices used and the design principles of the guides could influence the accuracy of implant placement.

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... 9 The deviations from the planned position of the placed implant may be influenced by the type of osteotomy drills and the design principle of the guided system. 10 Macrodesigns of implant fixtures also have more influence on the accuracy of the implant positioning than the implant fixture insertion protocol. 11 Many modern implant fixture designs have large aggressive designed threads in order to more tightly engage the residual ridge bone and therefore provide better primary stability. ...
... 17 The implant deviations in this study, notably the BLT implants, were similar to previous studies. 10,11 Comparing the deviation ranges with other types of implant design, the results here showed that the implant deviations were comparable to a previous study of other self-tapping implants. 9 The implant deviations may not only be the result of the macrothread designs alone. ...
Article
Purpose: Aggressive implant macrothread designs have been widely used. However, the effects of the aggressive thread design on the accuracy of static guided surgery, especially in a case of narrow residual ridge, have not been well-studied. The aim of this study was to evaluate the effects of two different implant macrothread designs and the residual ridge widths on the accuracy of tooth-supported static guided implant surgery. Materials and methods: Forty implant fixtures with two different macrodesigns: a conventional thread design bone level tapered (BLT), and an aggressive thread design bone level tapered (BLX) were placed in 40 simulated polyurethane models with narrow and wide residual ridges. The placed implant positions were compared with the planned implant position and angulational deviation, as well as three-dimensional (3D) deviations at the entry and apex of the implant were measured. One-way ANOVA with Tukey's multiple comparisons (ɑ = 0.05) were used to determine level of significance between the mean and variance deviation values. 95% confidence intervals and box plots were used to demonstrate the means and ranges of precision. Results: In terms of angulational deviation, there was no statistically significant difference in the mean deviations for both types of implants, p = 1.55 and p = 0.84 for wide and narrow ridge groups, respectively. However, the range of deviation was much larger in the narrow ridge of the BLX group compared to the BLT group. In both narrow ridge and wide ridge, the BLX group had lower mean 3D deviation values at both the entry and the apex with statistically significant differences for both entry point of the wide ridge (p = 0.027) and narrow ridge (p = 0.022) as well as at the apex of the wide ridge (p = 0.006) but not the apex of the narrow ridge (p = 0.142). Conclusion: The aggressive larger thread design of dental implants may influence the accuracy of implant placement more than the ridge dimension.
... Several designs of drilling systems are available for s-CAIS, including sleeve-in-sleeve system, sleeve-insleeve with self-locking, the mounted sleeve-on-drill, the integrated sleeve-on-drill, and the integrated sleeve-ondrill without a metal sleeve. The sleeve-in-sleeve system, used in the present study, was shown to lead to significantly less angular deviation compared to other systems listed above [40]. Regarding the IOS, the accuracy of IOS for single implant was widely demonstrated [41,42] and should, therefore, be considered as a valid research tool complying with (ALADA) principles for patient radiation safety [43][44][45][46]. ...
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Objectives To compare short-term outcomes after immediate restoration of a single implant in the esthetic zone with one-abutment one-time technique comparing a conventional (control) vs. a fully digital workflow (test). Materials and methods Eighteen subjects were randomly assigned to the two groups, and a digital implant planning was performed for all. In the test group, a custom-made zirconia abutment and a CAD–CAM provisional crown were prepared prior to surgery; implants were placed using a s-CAIS guide allowing immediate restoration after surgery. In the control group, the implant was placed free-handed using a conventional surgical guide, and a custom-made zirconia abutment to support a stratified provisional crown was placed 10 days thereafter, based on a conventional impression. Implant accuracy (relative to the planning), the provisional restoration outcomes, as well as PROMs were assessed. Results The implant positioning showed higher accuracy with the s-CAIS surgical guide compared to free-handed surgery (angular deviation (AD): 2.41 ± 1.27° vs. 6.26 ± 3.98°, p < 0.014; entry point deviation (CGD): 0.65 ± 0.37 mm vs. 1.27 ± 0.83 mm, p < 0.059; apical deviation (GAD): 1.36 ± 0.53 mm vs. 2.42 ± 1.02 mm, p < 0.014). The occlusion and interproximal contacts showed similar results for the two workflows ( p = 0.7 and p = 0.69, respectively). The PROMs results were similar in both groups except for impression taking with intra-oral scanning preferred over conventional impressions ( p = 0.014). Conclusions Both workflows allowed implant placement and immediate/early restoration and displayed similar clinical and esthetic outcomes. The fully digital workflow was associated with a more accurate implant position relative to planning. Clinical relevance Our results show that both conventional and digital workflow are predictive and provide similar clinical outcomes, with extra precision provided by digitalisation.
Article
Statement of problem Static guided implant surgery may be the most accurate method of implant placement to date. However, within the same guided implant system, whether accuracy is affected when placing a larger diameter implant that requires more drills than a smaller diameter implant is unclear. Purpose The purpose of this in vitro study was to evaluate the influence of implant diameter on the angulation and 3-dimensional (3D) deviations of posterior single implant placement using static guided surgery. Material and methods A polyurethane dental cast was made with an edentulous site at the maxillary right first molar position. Identical implant planning for each of 3 dental implant diameters 3.3, 4.1, and 4.8 mm (Straumann BLT) were made, and surgical guides for each implant diameters were fabricated by stereolithography. Fifteen implants of each diameter (N=45) were placed in simulated casts. A scan body was placed and the cast was scanned using an intraoral scanner. The positional discrepancies of implant placement, including angulation as well as 3D implant cervical and apex area deviations, were compared with the planned position. Linear ANOVA single factor analysis (ɑ=.05) was used, and box plots were made. Results The ranges of angulation deviations for 3.3-, 4.1-, and 4.8-mm implants were 3.6 degrees to 6.0 degrees, 3.7 degrees to 7.7 degrees, and 3.1 degrees to 6.7 degrees, respectively. The ranges of 3D implant entry deviations of 3.3-, 4.1-, and 4.8-mm implants were 0.96 to 1.4, 0.85 to 1.72, and 0.89 to 1.78 mm, respectively. The ranges of 3D implant apex of 3.3-, 4.1-, and 4.8-mm implants were 0.63 to 1.21, 0.64 to 1.48, and 0.48 to 1.27 mm, respectively. No statistically significant differences were found in any of the 3 measurements: P=.67 for deviation in angulation; P=.27 for 3D implant deviation of entry; and P=.3 for 3D implant deviation of the apex. Conclusions Implant diameters had no significant effect on placement deviations when a single posterior static guided surgery was used.
Chapter
3D printing or additive manufacturing has gained grounds in all disciplines of dentistry. The specialty of prosthodontics is not alienated from utilization of 3D printing. The inroads made by 3D printing in prosthodontics have initiated a new pattern of workflow of prosthesis fabrication. With the underpinning advantage of fewer assembly steps and elimination of the cumbersome manual laboratory operations, 3D printing promises a possibility of a cost-saving model coupled with digital designing and automated quality control. One can visualize the applications of 3D printing in all specialties of prosthodontics, including complete denture, fixed dental prosthesis, implant dentistry, and maxillofacial prosthesis fabrication, each moving at its own pace. As 3D printing revamps the landscape of prosthodontic practice, the dental practitioners need to familiarize themselves with the nuances of techniques, the mechanics, and the materials associated with the 3D printing process for each type of application in the discipline. The current chapter presents an overview of the numerous applications and workflow of 3D printing in prosthodontics. Comparison of the outcome of 3D printing with the conventional procedures and CAD CAM procedures shall also be drawn in order to highlight the prevailing stance as well as identify the further scope for improvement.Keywords3D printing complete dentures implant abutmentsProvisional restorationsMetal printingCeramic printingRemovable partial dentureSplints
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Costochondral grafts (CCG) are considered the best method for condylar reconstruction in young children with Pruzansky/Kaban type IIB and type III HFM. This orthodontic-surgical intervention immediately corrects the facial asymmetry by eliminating the hypoplastic mandible and the negative influence on the normal maxillary growth simultaneously with ramus height restoration. However, CCG precise surgical positioning is a challenge in these patients due to mandibular hypoplasia when the glenoid fossa is difficult to identify, or it might be absent. The aim of the 3D-printed jig is to manage the precise suitable placement position and fixation of the costochondral rib graft in relation to the contralateral unaffected temporomandibular joint and soft tissues. The jig may preserve the rib’s cartilage cap, prevent fractures at the costochondral junction, and result in a decrease in the risk of interference of cartilage growth.KeywordsHemifacial microsomiaPruzansky/Kaban classificationCostochondral graftsTemporomandibular jointJig3D printing3D models3D CT imaging
Article
Background: Static computer-assisted surgery (s-CAIS) and dynamic computer-assisted implant surgery (d-CAIS) are the main digital approaches in guiding dental implant placement. Purpose: The aim of this study was to explore and compare the learning curves for s-CAIS and d-CAIS by beginners. Materials and methods: Three dental students used each dental model for drilling five positions with missing teeth. Operators performed the drilling test for five sets of dental models with an interval of 7 ± 1 days assisted by the d-CAIS system. After a six-month break, the same students performed the drilling test again in the same way but with the s-CAIS system. A total of thirty models were used, and 150 implants were inserted. The operation time and relative deviations were recorded and calculated. Correlations between various deviation parameters and attempts were tested with independent-samples Kruskal-Wallis tests. Results: A significant difference between the two groups was found in the operation time (P < 0.001). For accuracy, the difference was found in the first attempt of coronal and apical deviations but disappeared as the training went on. As the practice progressed, improvement was evident in the d-CAIS group but not in the s-CAIS group. When reaching the plateau stage of the learning curve of the d-CAIS group (after five attempts), the influence of different methods of guidance was limited between the two groups. Conclusions: A learning curve effect was found in d-CAIS but not in s-CAIS in vitro tests by beginners. The operating procedure of dynamic navigated and static template-guided implant placement was easy to master.
Article
Background: Dynamic navigation approaches are widely employed in the context of implant placement surgery, with registration being integral to the accuracy of such navigation. Relatively few studies to date, however, have compared different registration approaches, and such a comparison has the potential to guide the development of more accurate and reliable clinical registration methodology. Purpose: This study was developed to compare the accuracy of dynamic navigation-based dental implant placement conducted using either U-tube or cusp registration methods. Materials and methods: Medical records from all patients that had undergone implant surgery between August 2019 and October 2020 in the First Clinical Division of the Peking University Hospital of Stomatology were retrospectively reviewed, with 64 patients and 99 implants ultimately meeting with study inclusion criteria. Implant placement accuracy was gauged via the superimposition of the planned implant position in preoperative cone-beam computed tomography (CBCT) images with the true postoperative implant position in postoperative CBCT images. Accuracy was measured based upon the angular deviation, entry deviation (3-dimensional [3D] deviation in the coronal aspect of the alveolar ridge), and apex deviation (3D deviation in the apical area of the implant) when comparing these two positions. Results: The angular deviation, entry deviation, and apex deviation of all analyzed implants were 3.29 ± 0.17°, 1.29 ± 0.07 mm, and 1.43 ± 0.08 mm, respectively, while in the cusp registration group these respective values were 3.25 ± 1.58°, 1.28 ± 0.60 mm, and 1.34 ± 0.63 mm as compared to 3.35 ± 1.78°, 1.30 ± 0.78 mm, 1.55 ± 0.9 mm in the U-tube group, respectively. No significant differences in accuracy were observed when comparing these two registration techniques. Conclusion: Dynamic computer-assisted surgical systems can facilitate accurate implantation, and both the U-tube and cusp registration methods exhibit similar levels of accuracy. As the cusp registration technique can overcome some of the limitations of the U-tube strategy without the need for an additional registration device, it may be more convenient for clinical use and warrants further research.
Article
Outcome studies have repeatedly shown that the apical endpoint of root canal preparation and filling is a determinate factor for the outcome of root canal treatment. Accurate determination of root canal length enhances the efficacy of chemo‐mechanical disinfection and prevents over/under instrumentation and over/under filling in relation to the canal terminus. Long and short root canal fillings are consistently reported to be associated with higher rates of post‐treatment endodontic disease. Although standards for undertaking and reporting diagnostic accuracy studies are available, publications dealing with the determination of root canal length are highly heterogeneous and describe procedures inconsistently. The aim of this review is to critically assess the methodology of publications in the past three decades. The process of planning, performing and analysing working length studies are presented stepwise with suggestions to optimise research methods.
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Background: An implant prosthesis aims to ensure the best possible rehabilitation of function and esthetics following tooth loss. Template-guided insertion is used to achieve an optimal position of the implant with regard to prosthetic restorability, bone availability, and condition of the surrounding soft tissues. The accuracy of template-guided implant placement is subject to various influencing factors. The clinically achievable accuracy depending on the macro design of the implant body was investigated in this prospective clinical study. Material and methods: In this prospective clinical study, 20 implants were placed in 20 patients. The implant had a pronounced conical outer geometry (Conelog ProgressiveLine, Camlog Wimsheim, Germany). Data from a study using an implant with a distinct cylindrical outer geometry were used as a comparison group (Conelog ScrewLine, Camlog, Wimsheim, Germany). The clinically achieved implant position was compared with the planned position. Results: The evaluation of the two-dimensional deviations in direction resulted in the following mean values (standard deviation) at the shoulder: 0.42 mm (0.33) in the buccolingual direction, 0.27 mm (0.25) in the mesiodistal direction, and 0.68 mm (0.55) in the apicocoronal direction. The mean angular deviation was 4.1° (2.3). The three-dimensional (3D) deviation was 0.94 mm (0.53) at the shoulder and 1.36 mm (0.62) at the apex of the implant. Significant differences between implants with different macro designs were found in the apicocoronal direction. In connection to this, a significant 3D deviation was found at the implant shoulder. Conclusions: Significant differences in height were found between the groups. The study had shown that the macro design of an implant has no influence on accuracy in all other directions. Overall, the implants showed a high level of accuracy and a low variation in values. The values were in the range determined by the template-guided insertion system in numerous other investigations. This provides good predictability of prosthetic rehabilitation. Trial registration: German Register for Clinical Studies (DRKS-ID: DRKS000018939 ). Date of registration: November 11, 2019.
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The present study aims to compare the accuracy of metal sleeve-free 3D-printed computer-assisted implant surgical guides (MSF group) (n = 10) with metal sleeve-incorporated 3D-printed computer-assisted implant surgical guides (MSI group) (n = 10). Implants of diameter 4.0 mm and 5.0 mm were placed in the left second premolars and bilateral first molars, respectively, using a fully guided system. Closed-form sleeves were used in teeth on the left and open-form sleeves on the right. The weight differences of the surgical guides before and after implant placement, and angular deviations before and after implant placement were measured. Weight differences were compared with Student’s t-tests and angular deviations with Mann–Whitney tests. Cross-sectional views of the insert parts were observed with a scanning electron microscope. Preoperative and postoperative weight differences between the two groups were not statistically significant (p = 0.821). In terms of angular deviations, those along the mesiodistal direction for the left second premolars were significantly lower in the MSF group (p = 0.006). However, those along the mesiodistal direction for the bilateral molars and those along the buccolingual direction for all teeth were not significantly different (p > 0.05). 3D-printed implant surgical guides without metal sleeve inserts enable accurate implant placement without exhausting the guide holes, rendering them feasible for fully guided implant placement.
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Purpose: To compare virtual planning accuracy of novel computer-assisted, template-based implant placement techniques, which make use of CAD/CAM stereolithographic surgical templates with or without metallic sleeves. Furthermore, to compare open versus closed sleeves for templates without metallic sleeves. Materials and methods: Any partially edentulous patients requiring at least one implant to be placed according to a computer-assisted template-based protocol were enrolled. Patients were randomized according to a parallel group design into two arms: Surgical template with or without metallic sleeves. Three deviation parameters (angular, horizontal, vertical) were defined to evaluate the discrepancy between the planned and placed implant positions. Results: No implants failed, and no complications were experienced. Forty-one implants were placed using surgical templates with metallic sleeves while 49 implants were placed with a surgical template without metallic sleeves. Of these, 16 implants were placed through open sleeves and 33 through closed sleeves. There was a statistically significant difference in angle (p = 0.0212) and in the vertical plan (p = 0.0073) with lower values for implants placed with a surgical template without metallic sleeves. In the test group, close sleeves were more accurate compared with open sleeves in angle (p = 0.0268) and in horizontal plan (p = 0.0477). Conclusion: With the limitations of the present study, surgical templates without metallic sleeves were more accurate in the vertical plan and angle compared to the conventional template with metallic sleeves. Open sleeves should be used with caution in the molar region only in case of reduced interarch space. Further research is needed to confirm these preliminary results.
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Article
Purpose: The aim of this systematic review was to analyze the accuracy of implant placement using computer-guided surgery and to compare virtual treatment planning and outcome in relation to study type (in vitro, clinical, or cadaver). A further objective was to compare the accuracy of half-guided implant surgery with that of full-guided implant surgery. Materials and methods: A PubMed search was performed to identify studies published between January 2005 and February 2015, searching the keywords "reliability AND dental implant planning" and "accuracy dental implant planning." Inclusion criteria were established a priori. Horizontal coronal deviation, horizontal apical deviation, angular deviation, and vertical deviation were analyzed. Results: A total of 186 articles were reviewed, and 34 fulfilled the inclusion criteria. Information about 3,033 implants was analyzed in 8 in vitro studies (543 implants), 4 cadaver studies (246 implants), and 22 clinical studies (2,244 implants). Significantly less horizontal apical deviation and angular deviation were observed in in vitro studies compared to clinical and cadaver studies, but there were no statistically significant differences in apical coronal deviation or vertical deviation between the groups. Compared to half-guided surgery, full-guided implant surgery showed significantly less horizontal coronal deviation for cadaver studies, significantly less horizontal apical deviation for clinical studies, and significantly less angular deviation for both clinical and cadaver studies. Conclusion: Implant placement accuracy was lower in clinical and cadaver studies compared with in vitro studies, especially in terms of horizontal apical deviation and angular deviation. Full-guided implant surgery achieved greater accuracy than half-guided surgery.
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Purpose: A recently introduced direct drill-guiding implant surgery system features minimal tolerance of surgical instruments in the metal sleeve by using shank-modified drills and a sleeve-incorporated stereolithographic guide template. The purpose of this study was to evaluate the accuracy of this new guided surgery system in partially edentulous patients using geometric analyses. Materials and methods: For the study, 21 implants were placed in 11 consecutive patients using the direct drill-guiding implant surgery system. The stereolithographic surgical guide was fabricated using cone-beam computed tomography, digital scanning, computer-aided design and computer-assisted manufacturing, and additive manufacturing processes. After surgery, the positional and angular deviations between planned and placed implants were measured at the abutment level using implant-planning software. The Kruskal-Wallis test and Mann-Whitney U test were used to compare the deviations (α=.05). Results: The mean horizontal deviations were 0.593 mm (SD 0.238) mesiodistally and 0.691 mm (SD 0.344) buccolingually. The mean vertical deviation was 0.925 mm (SD 0.376) occlusogingivally. The vertical deviation was significantly larger than the horizontal deviation (P=.018). The mean angular deviation was 2.024 degrees (SD 0.942) mesiodistally and 2.390 degrees (SD 1.142) buccolingually. Conclusion: The direct drill-guiding implant surgery system demonstrates high accuracy in placing implants. Use of the drill shank as the guiding component is an effective way for reducing tolerance.
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In vitro studies form a pivotal role in dental research contribution to a substantial evidence base. The reporting standards of these studies are not uniform thus resulting in lacunae in evidence reported. The effort of this concept note is to propose a Checklist for Reporting in vitro Studies (CRIS guidelines) that would promote quality and transparency in reporting in vitro studies.
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Objectives: To implement and evaluate the accuracy of a prototype dynamic computer-assisted surgery (CAS) system for implant osteotomy preparation and compare its accuracy vs. three commercial static CAS systems and the use of an acrylic stent. Material and methods: Eight osteotomies were prepared in radiopaque partially edentulous mandible and maxilla typodonts. After cone-beam CT acquisition, DICOM files were imported into a prototype dynamic, and three static CAS systems (NobelClinician, Simplant, and CoDiagnostiX). Implant placements were planned to replicate the existing osteotomies and respective guides were requisitioned, along with one laboratory-made acrylic guide. The eight osteotomies per jaw were transferred to one typodont pair mounted in a manikin in a clinical setting and the process was repeated for four additional pairs. The 80 (two jaws × eight holes × five pairs) osteotomies were filled with radiopaque cement in-between the testing series. Three clinicians experienced with the use of the static CAS softwares used in this study prepared each 400 (80 holes × five modalities) osteotomies. One clinician repeated the experiment twice, resulting in a total of 2000 (five clinicians × 400) osteotomies. The lateral, vertical, total, and angular deviations of the actual vs. the original osteotomies in the master typodonts were measured using stereo optical tracking cameras. Linear regression statistics using generalized estimating equations were used for comparisons between the five modalities and omnibus chi-square tests applied to assess statistical significance of differences. Results: The prototype dynamic CAS system was as accurate as other implant surgery planning and transfer modalities. The dynamic and static CAS systems provide superior accuracy vs. a laboratory-made acrylic guide, except vertically. Both dynamic and static CAS systems show on average <2 mm and 5 degrees error. Large deviations between planned and actual osteotomies were occasionally observed, which needs to be considered in clinical practice. Conclusions: The prototype dynamic CAS system was comparably accurate to static CAS systems.
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Article
To assess the literature on accuracy and clinical performance of computer technology applications in surgical implant dentistry. Electronic and manual literature searches were conducted to collect information about (1) the accuracy and (2) clinical performance of computer-assisted implant systems. Meta-regression analysis was performed for summarizing the accuracy studies. Failure/complication rates were analyzed using random-effects Poisson regression models to obtain summary estimates of 12-month proportions. Twenty-nine different image guidance systems were included. From 2,827 articles, 13 clinical and 19 accuracy studies were included in this systematic review. The meta-analysis of the accuracy (19 clinical and preclinical studies) revealed a total mean error of 0.74 mm (maximum of 4.5 mm) at the entry point in the bone and 0.85 mm at the apex (maximum of 7.1 mm). For the 5 included clinical studies (total of 506 implants) using computer-assisted implant dentistry, the mean failure rate was 3.36% (0% to 8.45%) after an observation period of at least 12 months. In 4.6% of the treated cases, intraoperative complications were reported; these included limited interocclusal distances to perform guided implant placement, limited primary implant stability, or need for additional grafting procedures. Differing levels and quantity of evidence were available for computer-assisted implant placement, revealing high implant survival rates after only 12 months of observation in different indications and a reasonable level of accuracy. However, future long-term clinical data are necessary to identify clinical indications and to justify additional radiation doses, effort, and costs associated with computer-assisted implant surgery.
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Implant treatment increasingly focuses on the reduction of treatment time and postoperative impairment. The improvement of 3D dental diagnosis by ConeBeam computed tomography allows detailed preparation for the surgical placement of dental implants under prosthetic considerations. While the first generation of implant planning software used high-contrast multislice computed tomography, software that has been specifically designed for ConeBeam computed tomography is now available. Implant placement can be performed using surgical guides or under the control of optical tracking systems. Surgical guides are more commonly used in private office owing to their availability. The accuracy for both techniques is clinically acceptable for achieving implant placement in critical anatomical indications. When using prefabricated superstructures and in flapless surgery, special abutments or an adjusted workflow are still necessary to compensate misfits of between 150 and 600 microm. The proposition to ensure proper implant placement by dentists with limited surgical experience through the use of surgical guides is unlikely to be successful, because there is also a specific learning curve for guided implant placement. Current and future development will continue to decrease the classical laboratory-technician work and will integrate the fabrication of superstructures with virtual treatment planning from the start.
Article
Background To ensure accurate implant placement, surgical guides are used to control the steps of implant placement surgery. Purpose Evaluation of the accuracy of implant placement in long span edentulous area by novice implant clinicians according to fully‐guided (FG), pilot‐guided (PG), and freehand (FH) placement protocols. Materials and methods Maxillary surgical models with four missing teeth from the right first canine to the first molar were produced by 3‐dimensional printing. Fourteen clinicians new to implant dentistry participated in the study, and each one of them inserted one canine and one molar implant for every implant placement protocol. All implant placement steps were completed in phantom heads to simulate the clinical situation. To evaluate the accuracy, the implant vertical, horizontal platform, horizontal apex, angle, and interimplant distance deviations from the planned positions were calculated. Results With the exception of vertical deviation, the FG placement was clearly more accurate than the PG and FH placements for all the variables for canine and molar implants. The PG placement was significantly more accurate than the FH placement for the horizontal platform and apex deviations, and interimplant distance deviation. The FG placement did not show a significant impact of the location of the implant, or the horizontal deviations of the platform or the apex. The PG and FH placements showed increased deviation at the canine implant than the molar implant, and at the apex of the implants than the platform of the implants. Conclusions Within the limitations of this in vitro study, novice clinicians achieved a significantly more accurate implant position with FG placement, followed by PG and FH placements respectively. Therefore, a form of guided surgery is beneficial for novice clinicians.
Article
Objectives: A randomized clinical trial was conducted to compare all three known static guided surgery protocols (pilot, partial, full) with each other and with freehand surgery in terms of accuracy, under the same conditions. Material and methods: 207 implants of the same brand and type were placed in 101 partially edentulous volunteers in need of implantation in the mandible or maxilla or both. All cases were digitally planned, and the comparison of the planned and actual implant positions was performed using a medical image analysis software with dedicated algorithms. The primary outcome variable was angular deviation (AD, degrees). The secondary outcome variables were coronal global deviation (CGD, mm), apical global deviation (AGD, mm) and voxel overlap (VO, %). Results: AD showed stepwise improvement in significant steps as the amount of guidance increased. The highest mean AD (7.03°± 3.44) was obtained by freehand surgery, and the lowest by fully guided surgery (3.04°± 1.51). As for the secondary outcome variables, all guided protocols turned out to be significantly superior to freehand surgery, but they were not always significantly different from each other. Conclusions: As for the comparison that this study sought to perform, it can be said that the static guided approach significantly improves the accuracy of dental implant surgery as compared to freehand surgery. Furthermore, the results suggest that any degree of guidance yields better results than freehand surgery and that increasing the level of guidance increases accuracy.
Article
Statement of problem: Implant guided surgery systems promise implant placement accuracy and precision beyond straightforward nonguided surgery. Recently introduced in-office stereolithography systems allow clinicians to produce implant surgical guides themselves. However, different implant designs and osteotomy preparation protocols may produce accuracy and precision differences among the different implant systems. Purpose: The purpose of this in vitro study was to measure the accuracy and precision of 3 implant systems, Tapered Internal implant system (BioHorizons) (BH), NobelReplace Conical (Nobel Biocare) (NB), and Tapered Screw-Vent (Zimmer Biomet) (ZB) when in-office fabricated surgical guides were used. Material and methods: A cone beam computed tomography (CBCT) data set of an unidentified patient missing a maxillary right central incisor and intraoral scans of the same patient were used as a model. A software program (3Shape Implant Studio) was used to plan the implant treatment with the 3 implant systems. Three implant surgical guides were fabricated by using a 3D printer (Form 2), and 30 casts were printed. A total of 10 implants for each system were placed in the dental casts by using the manufacturer's recommended guided surgery protocols. After implant placement, postoperative CBCT images were made. The CBCT cast and implant images were superimposed onto the treatment-planning image. The implant positions, mesiodistal, labiopalatal, and vertical, as well as implant angulations were measured in the labiolingual and mesiodistal planes. The displacements from the planning in each dimension were recorded. ANOVA with the Tukey adjusted post hoc pairwise comparisons were used to examine the accuracy and precision of the 3 implant systems (α=.05). Results: The overall implant displacements were -0.02 ±0.13 mm mesially (M), 0.07 ±0.14 mm distally (D), 0.43 ±0.57 mm labially (L), and 1.26 ±0.80 mm palatally (P); 1.20 ±3.01 mm vertically in the mesiodistal dimension (VMD); 0.69 ±2.03 mm vertically in the labiopalatal dimension (VLP); 1.69 ±1.02 degrees in mesiodistal angulation (AMD); and 1.56 ±0.92 degrees in labiopalatal angulation (ALP). Statistically significant differences (ANOVA) were found in M (P=.026), P (P=.001), VMD (P=.009), AMD (P=.001), and ALP (P=.001). ZB showed the most displacements in the M and vertical dimensions and the least displacements in the P angulation (P<.05), suggesting statistically significant differences among the M, VMD, VLP, AMD, and ALP. NB had the most M variation. ZB had the least P deviation. NB had the fewest vertical dimension variations but the most angulation variations. Conclusions: Dimensional and angulation displacements of guided implant systems by in-office 3D-printed fabrication were within clinically acceptable limits: <0.1 mm in M-D, 0.5 to 1 mm in L-P, and 1 to 2 degrees in angulation. However, the vertical displacement can be as much as 2 to 3 mm. Different implant guided surgery systems have strengths and weaknesses as revealed in the dimensional and angulation implant displacements.
Article
Objective: The aim of this study was to evaluate the effect of three different macrodesigns and two different insertion devices on the accuracy of static computer-assisted implant surgery (sCAIS). Materials and methods: Ninety implant replicas with three different macrodesigns: Soft tissue level (TL), bone level (BL), and bone level tapered (BLT) were placed in 30 dental models with two implant insertion devices: Guided adapter and guided screwed-in mount. Preoperative and postoperative positions of implants were compared and the mean angular deviation, crestal, and apical three-dimensional (3D) deviation were calculated for each implant macrodesign and each insertion device. Data were analyzed using analysis of variance, post hoc t-tests and Bonferroni-Holm's adjustment method. P values less than .05 were considered statistically significant. Results: BLT implants had lower mean 3D deviation values at the crest and the apex when compared with 3D deviations with BL and TL implants (P < .05). Also, BLT implants had lower angular deviations, when compared with BL and TL Implants, however, angular deviations were not statistically significant (P > .05). Considering the insertion device method, no significant differences were noted between insertion devices irrespective of the deviation analyzed. Conclusion: The macrodesign of dental implants may have an influence on the accuracy of sCAIS, with tapered designs offering slightly better positional accuracy than parallel-walled macrodesigns independent on the method of insertion used.
Article
Aim: This randomized controlled clinical trial (RCT) aimed to compare the accuracy of implant positions between static computer-assisted implant surgery (CAIS) and freehand implant surgery in a single edentulous space. Materials and methods: Sites with single edentulous spaces and neighbouring natural teeth were randomized into static CAIS or freehand implant surgery groups. In both groups, digital implant planning was performed using data from cone beam computed tomography (CBCT) and surface scans. In the static CAIS group, a surgical guide was produced and used for fully guided implant surgery, while in the freehand group, the implants were placed in a freehand manner. Postoperative CBCT was used for 9 measurements representing the deviations in angles, implant shoulders and apexes between planned and actual implant positions. Results: Fifty-two patients received 60 single implants. The median(IQR) deviations in angles, shoulders and apexes were 2.8(2.6)°, 0.9(0.8) mm and 1.2(0.9) mm, respectively, in the static CAIS group, and 7.0(7.0)°, 1.3(0.7) mm and 2.2(1.2) mm, respectively, in the freehand group. Statistically significant differences were found in 6 out of nine measured parameters using Mann Whitney U test (p < 0.05). Conclusion: Static CAIS provided more accuracy in implant positions than freehand placement in a single edentulous space. This article is protected by copyright. All rights reserved.
Article
Objectives The aim of this RCT was to compare the accuracy of implant placement between static and dynamic computer‐assisted implant surgery (CAIS) systems in single tooth space. Materials and methods A total of 60 patients in need of a single implant were randomly assigned to two CAIS groups (Static n = 30, Dynamic n = 30) and implants were placed by one surgeon. Preoperative CBCT was transferred to implant planning software to plan the optimal implant position. Implants were placed using either stereolithographic guide template (Static CAIS) or implant navigation system (Dynamic CAIS). Postoperative CBCT was imported to implant planning software, and deviation analysis with the planned position was performed. Primary outcomes were the deviation measurements at implant platform, apex, and angle of placement. Secondary outcome was the distribution of the implant deviation into each 3D direction. Results The mean deviation at implant platform and implant apex in the static CAIS group was 0.97 ± 0.44 mm and 1.28 ± 0.46 mm, while that in the dynamic CAIS group was 1.05 ± 0.44 mm and 1.29 ± 0.50 mm, respectively. The angular deviation in static and dynamic CAIS group was 2.84 ± 1.71 degrees and 3.06 ± 1.37 degrees. None of the above differences between the two groups reached statistical significance. The deviation of implants toward the mesial direction in dynamic CAIS group was significantly higher than that of the static CAIS (p = 0.032). Conclusions Implant placement accuracy in single tooth space using dynamic CAIS appear to be the same to that of static CAIS. (Thai Clinical Trials Registry TCTR20180826001).
Article
Background The insertion of dental implants by means of computer‐assisted template‐based surgery is an established method. Purpose To investigate the accuracy of a newly developed sleeve‐designed template and to evaluate differences between maxillary and mandibular implants as well as anterior versus posterior area. Materials and Methods Any partially edentulous patients requiring at least one implant to be planned on three‐dimensional cone beam computed tomography scan, according to a computer‐assisted template‐based protocol, were consecutively enrolled at two centers. Any potential implant position was considered eligible for the present trial. Outcome measures were: implant failure, complications, and accuracy. Results A total of 39 patients with 119 implants were evaluated. No patients dropped out during the study period (mean follow‐up 12.4 ± 7.1 months). Three implants failed at centre two, whereas, one complication was experienced at centre one (limited access in posterior area). Differences were not statistically significant (P > .05). The mean deviations were 0.53 ± 0.46 mm (range 0.05‐3.38 mm; 95% CI 0.32‐0.48 mm) in the horizontal plan (mesio‐distal); 0.42 ± 0.37 mm (range 0.0‐1.53 mm; 95% CI 0.26‐0.40 mm) in the vertical plan (apico‐coronal); and 1.43 ± 1.98° (range 0.03‐11.8°; 95% CI 0.31‐1.01°) in angle. Differences between centers were compared using the nonparametric Mann‐Whitney U test (P > .05). More accurate results were found for anterior implants in both horizontal plan and angle. Conclusion This study showed good precision in all the parameters measured. The results were thus in a range equal to or better than the mean precision found in numerous clinical trials described in the literature. Posterior implants were less accurate because of the use of open sleeves template.
Article
Objective The aim of this study was to evaluate the effect of guided sleeve height, drilling distance, and guided key height on accuracy of static Computer‐Assisted Implant Surgery (sCAIS). Materials and Methods Pre and post‐operative positions of implants placed in duplicate dental models were compared and recorded after placement of implants according to a standardized treatment planning and execution sCAIS protocol. Guided sleeve heights: 2 mm, 4 mm, 6 mm and guided key heights: 1 mm and 3 mm were equally randomized in six test groups with varying implant lengths (10‐16 mm) and surgical drilling protocols. The mean crestal and apical three‐dimensional (3D) deviation, as well as the angular deviation were calculated for each group. Data was analyzed using multivariate analysis anova. P values less than .05 were considered statistically significant. All P values of post‐hoc tests were corrected for multiple testing using Bonferroni‐Holm's adjustment method. Results 3D implant positioning accuracy was not significantly affected by the difference in sleeve height alone or by the implant length alone (P > .05). However, 3D and angular deviation values became significantly higher as the total drilling distance below the guided sleeve increased and significantly became lower as the guided key height above the sleeve increased. 18 mm drilling distance resulted in a significantly higher deviation, when compared to 14 mm or 16 mm drilling distances, irrespective of sleeve height or implant length (P < .01). 3 mm key height resulted in significantly less 3D deviation than 1 mm key height (P < .01). Conclusion Decreasing the drilling distance below the guided sleeve, by using shorter sleeve heights or shorter implants can significantly increase the accuracy of sCAIS.
Article
Objectives: To compare the deviation of different systems for Guided Implant Surgery (GIS) related to the specific tolerance between drills and sleeves. Material and methods: Four different systems for GIS and their appropriate sleeves were used: Camlog Guide (CG), Straumann Guided Surgery (SG), SIC Guide (SIG), and NobelGuide (NG). System-appropriate metal sleeves were inserted into plexiglass boxes, and guided drilling procedure was performed (i) holding the drills in the most centric position of the sleeves and (ii) applying forces eccentrically. Digital microscope images of the plexiglass boxes were taken and axial deviations were calculated based on the Pythagorean Theorem, whereas coronal and apical deviations were measured with a corresponding software-device and calculated by subtracting the measured deviations from the original diameter of the drills. Statistically significant differences between centric and eccentric drilling were determined applying the t-test for independent data. Results: The axial deviation ranged from 0° (SG) to 5.64° (CG). The apical deviations varied between 0.01 mm (SIG) and 3.2 mm (NG) and the coronal deviations ranged from 0.01 mm (SIG) to 1.60 mm (NG). In terms of angular deviation, there were statistically significant differences between centric and eccentric drilling for all four systems. Coronal and apical deviations, showed no statistical significance between centric and eccentric drilling for SIG and NG, in contrast to CG and SG. Conclusions: The clinician may have considerable impact on the accuracy of GIS when applying eccentric forces.
Article
This study investigated the effect of implant design and bone quality on insertion torque (IT), implant stability quotient (ISQ), and insertion energy (IE) by monitoring the continuous change in IT and ISQ while implants were inserted in artificial bone blocks that simulate bone of poor or poor-to-medium quality. Polyurethane foam blocks (Sawbones) of 0.16 g/cm³ and 0.32 g/cm³ were respectively used to simulate low density and low- to medium-density cancellous bone. In addition, some test blocks were laminated with a 1-mm 0.80 g/cm³ polyurethane layer to simulate cancellous bone with a thin cortical layer. Four different implants (Nobel Biocare Mk III-3.75, Mk III-4.0, Mk IV-4.0, and NobelActive-4.3) were placed into the different test blocks in accordance with the manufacturer's instructions. The IT and ISQ were recorded at every 0.5-mm of inserted length during implant insertion, and IE was calculated from the torque curve. The peak IT (PIT), final IT (FIT), IE, and final ISQ values were statistically analyzed. All implants showed increasing ISQ values when the implant was inserted more deeply. In contrast to the ISQ, implants with different designs showed dissimilar IT curve patterns during the insertion. All implants showed a significant increase in the PIT, FIT, IE, and ISQ when the test-block density increased or when the 1-mm laminated layer was present. Tapered implants showed FIT or PIT values of more than 40 Ncm for all of the laminated test blocks and for the nonlaminated test blocks of low to medium density. Parallel-wall implants did not exhibit PIT or FIT values of more than 40 Ncm for all of the test blocks. NobelActive-4.3 showed a significantly higher FIT, but a significantly lower IE, than Mk IV-4.0. While the existence of cortical bone or implant designs significantly affects the dynamic IT profiles during implant insertion, it does not affect the ISQ to a similar extent. Certain implant designs are more suitable than others if high IT is required in bone of poor quality. The manner in which IT, IE, and ISQ represent the implant primary stability requires further study.
Article
The aim of this in-vitro study was to compare the tolerance of surgical instruments in surgical guides produced by 3-D printing, without metal sleeves to a surgical guide with conventional metal sleeves from two different manufacturers. Lateral movements of drill tips caused by tolerance between the sleeve and drill key and between the drill key and the drill were recorded after application of a standardized force to the surgical instruments. Four groups were tested: Control 1 (C1): metal sleeve from commercially available surgical system 1; Test 1 (T1): 3-D-printed sleeve for surgical system 1; Control 2 (C2): metal sleeve from commercially available surgical system 2. Test 2 (T2): 3-D-printed sleeve for surgical system 2. The mean total lateral movement was 0.75 mm (0.5-1.04 mm) in the C1 group and 0.91 mm (0.54-1.34 mm) in the C2 group. The mean amount of movement from tolerance between sleeve and drill-guiding key was 0.31 mm (range 0.22-0.41 mm) in C1 and 0.42 mm (range 0.29-0.56 mm) in C2. This lateral movement was in mean reduced by 0.24 mm (32%) in T1 and by 0.39 mm (43%) in T2 group. This reduction was statistically significant in both groups (P < 0.001). The tolerance of surgical instruments and the lateral movements of the drills were significantly reduced by the use of 3-D printing with reduced sleeve diameter. This reduction could improve the overall accuracy in computer-assisted template-guided implant dentistry. The lateral movement of the drill can be further reduced by using a shorter drill and a higher drill key. This can be considered during implant planning and CAD/CAM of surgical guides.
Article
Purpose: Recent clinical studies have shown that implant placement is highly predictable with computer-generated surgical guides; however, the reliability of these guides has not been compared to that of conventional guides clinically. This study aimed to compare the accuracy of reproducing planned implant positions with computer-generated and conventional surgical guides using a split-mouth design. Materials and methods: Ten patients received two implants each in symmetric locations. All implants were planned virtually using a software program and information from cone beam computed tomographic scans taken with scan appliances in place. Patients were randomly selected for computer-aided design/computer-assisted manufacture (CAD/CAM)-guided implant placement on their right or left side. Conventional guides were used on the contralateral side. Patients underwent operative cone beam computed tomography postoperatively. Planned and actual implant positions were compared using three-dimensional analyses capable of measuring volume overlap as well as differences in angles and coronal and apical positions. Results were compared using a mixed-model repeated-measures analysis of variance and were further analyzed using a Bartlett test for unequal variance (α = .05). Results: Implants placed with CAD/CAM guides were closer to the planned positions in all eight categories examined. However, statistically significant differences were shown only for coronal horizontal distances. It was also shown that CAD/CAM guides had less variability than conventional guides, which was statistically significant for apical distance. Conclusion: Implants placed using CAD/CAM surgical guides provided greater accuracy in a lateral direction than conventional guides. In addition, CAD/CAM guides were more consistent in their deviation from the planned locations than conventional guides.
Article
The aim of the present study was to assess the clinical relevance of the potential mechanical error (intrinsic error) caused by the cylinder-burr gap in a 'single type' stereolithographic surgical template in implant guided surgery. 129 implants were inserted in 12 patients using 18 templates. The pre- and postoperative computed tomography (CT) scans were matched allowing comparison of the planned implants with the placed ones. Considering only the angular deviation values, the t test was used to determine the influence of the guide fixation and the arch of support on accuracy values. The Pearson correlation coefficient was used to correlate angular deviation and bone density. The intrinsic error was mathematically evaluated. t test results indicated that the use of fixing screws (P=009) and the upper arch support (P=027) resulted in better accuracy. The Pearson correlation coefficient (0.229) indicated a significant linear correlation between angular deviations and bone density (P=009). A mean intrinsic error of 2.57 was mathematically determined considering only the angular deviation, as it was not influenced by other variables. The intrinsic error is a significant factor compared to all the variables that could potentially affect the accuracy of computer-aided implant placement.
Article
Objectives: Recently, guided implant surgery has been introduced and several studies verified its accuracy. While those studies reported on the accuracy of the entire procedure, this experiment wanted to evaluate the degree of deviation that can occur during the drilling procedure alone, due to the tolerance of the drill in the sleeve insert. Material and methods: Drilling was executed in a plexi-glass box with a maximal inclination of the drills within the sleeve insert. Different sleeve inserts, sleeve positions, sleeve heights, sleeve insert heights and diameters were evaluated. Results: The two tested sleeve inserts gave a maximum deviation in angulation of 5.2° and a maximum horizontal deviation of 1.3 mm at the implant shoulder and 2.4 mm at the apex for a 13 mm implant. These deviations decreased if the distance of the sleeve above the plexi-glass box became smaller and hand hold sleeve inserts gave less deviation than drill hold sleeve inserts. The deviation increased by longer implant length, larger drill key diameter, shorter sleeves and/or drill key heights. Conclusions: For a minimal deviation during the surgery with a stereolithographic guide, it is very important to use the drill in a centric position, parallel to the cylinder. The use of longer drill keys and sleeves are critical for optimal accuracy.
Article
Recently, guided surgery has been introduced and several papers verified its accuracy. While those studies reported on the accuracy of the entire procedure, this experiment wanted to make clinicians aware of the amount of the deviation that can already occur during the drilling procedure alone, due to the tolerance of the drill in the drill key. Drilling was executed in plexi-glass with a maximal inclination of the drills within the drill keys. A mean deviation in angulation of 4.7 degrees occurred with a mean horizontal deviation at the implant shoulder of 0.8 mm and 1.8 mm at the apex of 13 mm implant. The deviation was further dependent of the implant length, the distance of the sleeve above the bone and the respective guiding system. Increasing the height of the drill key will minimize the inaccuracy. The results from this experiment showed the importance of keeping the drill parallel to the guide in a centric position.
Article
Fabrication of a proper surgical guide is critical for success of implant restorations. The effects of the dimensional factors of the surgical guide on implant placement have not been studied. The purpose of this study was to determine the effect of varied dimensions (diameter, length, and distance between the underside of the surgical guide and the implant recipient site) of a surgical guide on the accuracy of implant angulation. In this in vitro study, 240 implant recipient sites were randomly prepared using varied dimensions of a surgical guide. The varied dimensions of the surgical guide's channel and distance were: channel diameter (2, 3, 4, or 5 mm), channel length (6 or 9 mm), and distance between the underside of the surgical guide and the simulated implant recipient site (2 or 4 mm). From these varying dimensions and distances, 16 combinations of dimensions and distances were tested. For each combination, 15 simulated implant recipient site (SIRS) specimens were prepared. The deviated angulation (DA) from the midpoint of the top surface of the 1- x 1-inch simulated implant recipient site (each simulated implant recipient acrylic block contained 5 SIRS of 1 x 1 inch), in the right-to-left (DA(RL)) and front-to-back (DA(FB)) directions, were measured in degrees using a protractor. The data was analyzed using factorial analysis of variance and Tukey's HSD test (alpha=.05). The DA(RL) , in degrees, at a channel length of 9.0 mm (2.33 +/- 1.27) was significantly smaller than at a channel length of 6.0 mm (3.0 +/- 1.42, P =.0001). The DA(RL) , in degrees, at a distance of 4.0 mm (2.13 +/- 1.16) was significantly smaller than at a distance of 2.0 mm (3.16 +/- 1.39, P =.0001). Also, a significant interaction for DA(RL) was found between diameter and distance ( P <.05). For DA(FB) , the varying diameters ( P <.05), lengths ( P =.0001), and distances ( P =.0001) showed significant differences. The DA(FB) at a channel length of 9.0 mm (2.56 degrees +/- 1.51) was significantly smaller than that at 6.0 mm (3.82 degrees +/- 1.87). Significant interactions found for DA(FB) were: diameter by length ( P =.0001), diameter by distance (F=4.547, P =.004), and length by distance (F=11.512, P =.001). Within the limitations of this study, the results suggest channel length as the primary controlling factor in minimizing deviated angulations.
Standard specification for rigid polyurethane foam for use as a standard material for testing Orthopaedic devices and instruments
ASTM F1839-08 (2016): Standard specification for rigid polyurethane foam for use as a standard material for testing Orthopaedic devices and instruments. ASTM International; 2016. https://doi.org/10. 1520/F1839-08R16.
Accuracy of a direct drill-guiding system with minimal tolerance of surgical instruments used for implant surgery: a prospective clinical study
  • D H Lee
  • An Sy
  • M H Hong
  • K B Jeon
  • K B Lee
Lee DH, An SY, Hong MH, Jeon KB, Lee KB. Accuracy of a direct drill-guiding system with minimal tolerance of surgical instruments used for implant surgery: a prospective clinical study. J Adv Prosthodont. 2016;8(3):207-213.