Apical Deviation Research Articles

Influence of the tooth position, guided sleeve height, supporting length, manufacturing methods, and resin E-modulus on the in vitro accuracy of surgical implant guides in a free-end situation.

The study aims to evaluate the effect of tooth position, sleeve height, supporting length, resin E-modulus, and manufacturing method on the accuracy of dental implants placed in vitro fully guided in a lower jaw free-end situation. Using resin clones of a patient case providing a free-end situation 384 implants has been experimentally placed guided. The accuracy of postoperative implant position analyzed depending on the tooth position (first and second molar), sleeve height (2 and 6mm), supporting length (tooth no. 37-33 and 37 43), resin E-modulus (<2,000, >2,000, and >3,000MPa), and manufacturing method (milled, printed). To determine the three-dimensional accuracy angular deviation, mean crestal, apical deviation, and the linear vertical deviation at apex were calculated separately for each group (n=12). The accuracy of implant placement using milled guides was affected only by the tooth position, indicating stronger deviation of implants replacing second molars than first molars. Considering printed guides, the implant position was influenced by tooth position, sleeve height, and supporting length. Linear vertical deviation >1mm was found for printed materials with the lowest E-modulus at tooth position no. 37. Logistic regression analysis revealed a significant lower odds for linear vertical deviation >1mm for materials with higher E-modulus (OR: 0.04; 95% CI:0.01-0.97; p=.048) and higher ratio for smaller sleeve height (OR: 2.77; 95% CI:1.20-6.38; p=.017). Accuracy of implant placement in a free-end situation lacking distal tooth support is superior for milled as compared to 3D-printed surgical guides. When using 3D-printed surgical guides, smaller sleeve heights and extended tooth support improve the accuracy of implant placement.

Accuracy and Efficiency of 3-dimensional Dynamic Navigation System for Removal of Fiber Post from Root Canal–Treated Teeth

IntroductionThe purpose of this study was to investigate the accuracy and efficiency of the 3-dimensional dynamic navigation system (DNS) compared with the freehand technique (FH) when removing fiber posts from root canal–treated teeth. MethodsTwenty-six maxillary teeth were included. Teeth were root canal treated and restored with Parapost Taper Lux (Coltene/Whaledent, Altstätten, Switzerland) luted with RelyX Unicem (3M ESPE, St Paul, MN). A core buildup was then performed using Paracore (Coltene/Whaledent). Teeth were mounted in tissue-denuded cadaver maxillae. Teeth were divided into 2 groups: the DNS group (n = 13) and the FH group (n = 13). Cone-beam computed tomographic scans were taken pre- and postoperatively. The drilling path and depth were planned virtually using X-guide software (X-Nav Technologies, Lansdale, PA) in both groups. For the DNS group, drilling was guided with X-Nav software and the FH group under a dental operating microscope. Global coronal and apical deviations, angular deflection, operation time, and the number of mishaps were compared between the groups to determine the accuracy and efficiency. The 3-dimensional volume (mm3) of all teeth was calculated before and after post removal using the Mimics Innovation Suite (Materialise NV, Leuven, Belgium). The Shapiro-Wilk, 1-way analysis of variance, and Fisher exact tests were used (P < .05). ResultsThe DNS group showed significantly less global coronal and apical deviations and angular deflection than the FH group (P < .05). DNS required less operation time than FH. Moreover, the DNS technique had significantly less volumetric loss of tooth structure than the FH technique (P < .05). ConclusionsThe DNS was more accurate and efficient in removing fiber posts from root canal–treated teeth than the FH technique.

Fully versus conventionally guided implant placement by dental students: A randomized controlled trial

To compare fully guided with conventionally guided implant surgery performed by dental students in terms of deviation of actual implant position from an ideal implant position. Twenty-five patients in need of 26 straightforward implant-supported single crowns were randomly allocated to a fully guided (FG, n=14) or a conventionally guided (CG, n=12) implant surgery. In the preoperative CBCTs, 3 experienced investigators placed a virtual implant in the ideal position, twice, allowing deviational analysis in the facio-lingual (coronal) and mesio-distal (sagittal) planes for 7 parameters. Facio-lingual crestal deviation, facio-lingual apical deviation, facio-lingual angular deviation, mesio-distal crestal deviation, mesio-distal apical deviation, mesio-distal angular deviation, and vertical deviation between the ideal, virtually placed position and actual implant position for the FG and CG groups were compared statistically (p<.05). Statistically significant differences between ideal and actual implant position were only seen for the facio-lingual apical deviation (p=.047) and for the facio-lingual angular deviation (p=.019), where the CG group deviated more from the ideal position than the FG group. The 5 other examined variables did not show any significant differences, and none of the implants in the FG group and CG group were placed in conflict with the clinical guidelines. The present study reported no difference in 5 out of 7 deviational parameters concerning actual implant position in relation to ideal implant position between a FG and CG implant placement protocol performed by dental students. Facio-lingual angular deviation and apical deviation were lower, when a FG protocol was followed. All implants were positioned according to clinical guidelines.

Whole-Process Digitalization-Assisted Immediate Implant Placement and Immediate Restoration in the Aesthetic Zone: A Prospective Study.

BackgroundThis study explored the clinical effects of whole-process digitalization (WD)-assisted immediate implant placement (IIP) and immediate restoration (IR) in the aesthetic zone and clarified the clinical procedures.Material/MethodsPatients who received maxillary aesthetic region IIP and IR treatment were randomly distributed into WD-assisted and conventional groups. Postoperative assessment included implant accuracy, marginal bone loss, aesthetic evaluation, and patient satisfaction evaluation. The aesthetic evaluation included visual analog score (VAS), pink aesthetic score (PES), and white aesthetic score (WES). Numerical data, measurement data, and grade data were analyzed by χ2 test, t test, and Mann-Whitney U test.ResultsThe WD-assisted group exhibited decreased implant accuracy, including coronal deviation, apical deviation, angular deviation, and depth deviation, compared with the conventional group (P<0.05). The marginal bone loss in both the mesiodistal direction and the buccolingual direction were significantly lower in the WD-assisted group than in the conventional group (P<0.05). The VAS, PES, and WES were all significantly higher in the WD-assisted group than in the conventional group at 3, 6, and 12 months after surgery (P<0.05). Patients in the WD-assisted group also reported a higher satisfaction level than those in the conventional group (P<0.05).ConclusionsWD-assisted IIP and IR treatment in the aesthetic zone increased implant accuracy, decreased marginal bone loss, improved aesthetic effect, and increased patient satisfaction compared with conventional treatment. Therefore, WD-assisted IIP and IR treatment constitutes a promising approach in clinical oral implantology.

The accuracy of computer-aided design and manufacturing surgical-guide for infrazygomatic crest miniscrew placement

Objectives: Infrazygomatic crest (IZC) surgical guides have been employed to prevent any avoidable complications during miniscrew insertion. The purpose of this study was to evaluate the accuracy of IZC miniscrew placement when using a surgical-guide developed by computer-aided design and manufacturing (CAD/CAM) techniques. Materials and Methods: Ten patients were scanned with cone-beam computed tomography for three-dimensional (3D) planning of IZC miniscrew placements. The upper arches were scanned separately, and virtual miniscrews were placed in the position planned by 3D software. The CAD/CAM surgical guides were designed and fabricated individually to enable accurate miniscrew placement. Subsequently, 20 self-drilling miniscrews were inserted at the right and left IZC areas using 5 CAD/CAM surgical guides (CS group, n = 10) and direct insertion (DI group, n = 10), respectively. Pre- and post-operative digital model images were compared, actual and planned miniscrew positions were superimposed and measured for 3D angular and distance deviations in the two groups. Comparisons between groups were made using the Kruskal–Wallis test. Results: In the CS group, the median coronal and sagittal angular deviations were 2.95 degrees (range 0.34–5.26 degrees) and 2.05 degrees (range 0.38–4.08 degrees), respectively, while the median coronal and apical deviations were 0.39 mm (range 0.24–0.51 mm) and 0.50 mm (range 0.16–0.66 mm). These deviations differed significantly from those of the DI group. Conclusion: The IZC CAD/CAM surgical guide has made it possible to control miniscrew placement with high precision.

Although the Computer-Aided Implant Placement Technique has Statistically Significant Better Outcomes Than Partially Guided and Free-Handed Implant Placement, the Observed Clinical Outcome Measures are Similar and Insignificant

Tattan M, Chambrone L, González-Martín O, Avila-Ortiz G. Static computer-aided, partially guided, and free-handed implant placement: A systematic review and meta-analysis of randomized controlled trials. Clin Oral Implants Res. 2020 Oct;31(10):889-916. doi: 10.1111/clr.13635. Epub 2020 Jul 26. PMID: 32654230. Information not available. Systematic review with meta-analysis.

Geometric Analysis of the Distolingual Root and Canal in Mandibular First Molars: A Micro–computed Tomographic Study

IntroductionThe purpose of this study was to comprehensively assess by micro–computed tomographic imaging the anatomic features of distolingual (DL) roots and canals in mandibular first molars collected from 1 population. MethodsOne hundred two specimens were examined for the location and initial direction of the DL canal and the relationship between the distance of apical deviation and the angle of root curvature. ResultsAll DL roots had only 1 canal. A new 7-category classification system is proposed for the DL roots of mandibular first molars. Most DL roots were type IV (28 teeth), type III (26 teeth), and type V (25 teeth). The average canal curvature in all root types was over 25°. There was a positive correlation between the angles of root and canal curvature for types II, IV, and V (P < .05) but not for types I and III (P > .05). In the buccolingual view, most DL roots were straight, whereas in the mesiodistal view the root curvature was close to the maximum value. The orifice of the DL canal was 4 times further from the line that bisects a line between the mesiobuccal and mesiolingual canal orifices than the distobuccal canal. The angle between the mesiobuccal-mesiolingual line and the horizontal projection of the coronal third of the DL canal on the pulp floor was 8.1° ± 10.0° and 6.1° ± 8.2° for teeth from the left and right side, respectively. The angle between the inserted simulated file and the cementoenamel junction was 57.9° ± 6.3°. Seventy-three percent of the DL canals had no constriction in the apical area. The DL canals were narrow and had a conical frustum-like shape with a 0.04 taper at the apical portion. ConclusionsThe novel classification of the DL roots helps to better understand the clinically challenging anatomy of the root and canal.

Animal experiment on the accuracy of the Autonomous Dental Implant Robotic System

Objective: To evaluate the accuracy of the Autonomous Dental Implant Robotic System (ADIR) in vivo through animal experiments. Methods: Nine canine models with bilateral mandibular premolars loss were prepared. Two implants were placed in each side of canine's mandibular edentulous area. On each side, the two implants were completed by ADIR (robot group) and one experienced doctor using digital full-guided plate (guide template group) respectively. After the operation, the deviation between the actual implant position and the planned position was evaluated. The primary stability of the implant was measured, and the results of the robot group and the guide template group were statistically analyzed. Results: ADIR could successfully place implant for missing teeth in animals, and the coronal deviation, apical deviation and angular deviation [M(Q)] were 0.269 (0.152) mm, 0.254 (0.218) mm and 0.989° (0.517°) respectively, which were significantly lower than those of guide template group [the coronal deviation, apical deviation and angular deviation were 0.910 (0.872) mm, 1.179 (1.176) mm and 4.209°(5.208°) respectively] (P<0.05). Besides, there was no significant difference in the primary stability of the implant between the two groups (P>0.05). Conclusions: This study confirmed the accuracy of the ADIR in vivo, and laid a foundation for further clinical trials.

The accuracy of implant placement with computer-guided surgery in partially edentulous patients and possible influencing factors: A systematic review and meta-analysis.

To review the current clinical studies regarding the accuracy of implant computer-guided surgery in partially edentulous patients and investigate potential influencing factors. Electronic searches on the PubMed and Cochrane Central Register of Controlled Trials databases, and subsequent manual searches were performed. Two reviewers selected the studies following our inclusion and exclusion criteria. Qualitative review and meta-analysis of the implant placement accuracy were performed to analyze potential influencing factors. Angular deviation, coronal deviation, apical deviation, and depth deviation were evaluated as the accuracy outcomes. Eighteen studies were included in this systematic review, including six randomized controlled trials, nine prospective studies, and three retrospective clinical studies. A total of 1317 implants placed in 642 partially edentulous patients were reviewed. Eight studies were evaluated using meta-analysis. Fully guided surgery showed statistically higher accuracy in angular (P <0.001), coronal (P <0.001), and apical deviation (P <0.05) compared with pilot-drill guided surgery. A statistically significant difference (P <0.001) was also observed in coronal deviation between the bounded edentulous (BES) and distal extension spaces (DES). A significantly lower angular deviation (P <0.001) was found in implants placed using computer-aided design/computer-aided manufacturing (CAD/CAM) compared to the conventional surgical guides. The edentulous space type, surgical guide manufacturing procedure, and guided surgery protocol can influence the accuracy of computer-guided surgery in partially edentulous patients. Higher accuracy was found when the implants were placed in BES, with CAD/CAM manufactured surgical guides, using a fully guided surgery protocol.

Accuracy of Guided Implant Surgery in the Edentulous Jaw Using Desktop 3D-Printed Mucosal Supported Guides.

Purpose: The aim of this in vitro study is to evaluate the accuracy of implant position using mucosal supported surgical guides, produced by a desktop 3D printer. Methods: Ninety implants (Bone Level Roxolid, 4.1 mm × 10 mm, Straumann, Villerat, Switzerland) were placed in fifteen mandibular casts (Bonemodels, Castellón de la Plana, Spain). A mucosa-supported guide was designed and printed for each of the fifteen casts. After placement of the implants, the location was assessed by scanning the cast and scan bodies with an intra-oral scanner (Primescan®, Dentsply Sirona, York, PA, USA). Two comparisons were performed: one with the mucosa as a reference, and one where only the implants were aligned. Angular, coronal and apical deviations were measured. Results: The mean implant angular deviation for tissue and implant alignment were 3.25° (SD 1.69°) and 2.39° (SD 1.42°) respectively, the coronal deviation 0.82 mm (SD 0.43 mm) and 0.45 mm (SD 0.31 mm) and the apical deviation 0.99 mm (SD 0.45 mm) and 0.71 mm (SD 0.43 mm). All three variables were significantly different between the tissue and implant alignment (p < 0.001). Conclusion: Based on the results of this study, we conclude that guided implant surgery using desktop 3D printed mucosa-supported guides has a clinically acceptable level of accuracy. The resilience of the mucosa has a negative effect on the guide stability and increases the deviation in implant position.

Accuracy of Miniscrew Insertion Using a Customized Printed Three-Dimensional Surgical Guide (A Comparative Split Mouth Study)

Aim of the study This study was conducted to evaluate the accuracy of a new constructed 3D CBCT image–based surgical guide for miniscrew implantation . Materials and Methods Twenty five adult patients of were included in the current study (13 males and 12 females). Mandibular arch of every patient was randomly divided into : one experimental side ( miniscrews were placed using surgical guide ) and one comparison side ( miniscrews were placed conventionally without surgical guide. For both sides (experimental and comparison side); Linear measurements were recorded on the software of coronal deviations, apical deviations and vertical deviations . Also , angular measurements were recorded in both mesiodistal and buccolingual dimensions for the actual plan and the real mini screws . At the end all deviations were calculated and statistical analysis was performed. Results A significantly higher level of accuracy (lower differences from the actual value) was achieved with the surgical guide technique (p < 0.001) than hand drilling technique for all measurements . Conclusions Three Dimensional surgical guides provide a precise method for miniscrew placement into the dentoalveolar bone.

Determining accuracy of sleeveless tooth-supported surgical guide for guided implant surgery: A retrospective observational study

Aim: The advances in CAD/CAM technique have enabled digital data from the virtual setting to be transferred to the real clinical output using surgical guides. Evidence for the accuracy of surgical guides with metal sleeves has been documented. However, the sleeveless surgical guide has not yet been analyzed for its accuracy in clinical situations. The purpose of the study is to determine the accuracy of the sleeveless tooth-supported surgical guide for guided implant surgery. Materials and Methods: This retrospective observational study evaluates data of 25 patients selected randomly with single implants placed using the sleeveless surgical guide, which was collected from a single center at Thane. Cone-beam computed tomography of the treatment planning and the post-implant placement data were superimposed on each other and analyzed using Evalunav (3.0 version, Claronav, Toronto, Canada) software. Descriptive analysis was done. Coronal, apical, and angular deviations were calculated and assessed using a one-sample t-test. Results: It was found that the mean coronal deviation between the planned and placed implants was 0.73± 0.4 mm (0.12–1.81 mm), the mean apical deviation was 0.81± 0.43 mm (0.12–1.66 mm), and the angular deviation was 2.32° ± 0.98° (0°–4.78°). There was a statistically highly significant difference between the achieved and accepted values (P < 0.01) with a lower deviation achieved when compared with the acceptable values. Conclusion: It was concluded that the 3d printed tooth-supported surgical guide with no metal sleeves has acceptable accuracy for placing dental implants using the guided technology.

Accuracy of Full-Guided and Half-Guided Surgical Templates in Anterior Immediate and Delayed Implantation: A Retrospective Study.

Computer-aided implantology has developed rapidly in recent years, this study aimed to compare the accuracy of guided-surgery between anterior immediate and delayed implantation, and simultaneously assess the effect of full-guided and half-guided templates on accuracy values. Seventy-six implants were inserted in 63 patients using full-guided or half-guided template in the anterior zone. Postoperative cone beam computed tomography (CBCT) was matched with preoperative planning to evaluate the deviation between actual and planned implants. No statistical difference was found in any deviation between immediate and delayed implantation (p > 0.05). In anterior immediate implantation, the global coronal, apical, depth and angular deviations of full-guided templates were all significantly lower than those of half-guided templates (0.66 ± 0.26 vs. 1.10 ± 0.76 mm, 0.96 ± 0.41 vs. 1.43 ± 0.70 mm, 0.46 ± 0.24 mm vs. 0.93 ± 0.79 mm and 1.69° ± 0.94° vs. 2.57° ± 1.57°). While in delayed implantation, full-guided templates only perform better with statistical significance on global apical and depth deviation (1.01 ± 0.42 vs. 1.51 ± 0.55 mm and 0.32 ± 0.26 vs. 0.71 ± 0.47 mm). After excluding the influence of depth deviation, the coronal and apical deviations between the two systems in immediate implantation and the apical deviations in delayed implantation had no statistical difference. Within the limit of this study, the results suggested the accuracy of guided-surgeries for anterior immediate and delayed implantations was comparable, and full-guided template was more accurate for immediate and delayed implantation.

Accuracy of dynamic navigation compared to static surgical guide for dental implant placement

ObjectivesTo compare the accuracy of dynamic navigation (DN) with a static surgical guide (SSG) for dental implant placement and the influence factors such as the experience of the surgeon and the implant sites.Methods and materialsA total of 38 implants, which underwent the dynamic navigation, and 57 implants which underwent a static surgical guide were enrolled in the retrospective study. Coronal deviation, apical deviation, and angular deviation were compared between the DN and SSG groups, along with the different experience level of surgeons and implant sites in the DN group.ResultsThere were no statistically significant differences between the DN and SSG groups, and the experience level of the surgeons and implant sites in the DN group. However, the apical deviation of the DN was slightly higher than the SSG group in the anterior teeth (P = 0.028), and the angular deviation of DN was smaller than the SSG group in the molar.ConclusionDynamic navigation can achieve accurate implant placement as well as the static surgical guide. Additionally, the experience level of the surgeon and implant site do not influence the accuracy of dynamic navigation, while the accuracy of DN seems higher than the SSG in molar.

Accuracy of static digital surgical guides for dental implants based on the guide system: A systematic review

In the present study, we tried to review the current literature, focusing on the effect of different guide systems on the accuracy of the digital surgical guides.A search in PubMed’s database, without any date restriction, was performed using keywords based on the PICO question. 54 of the 2378 articles’ were chosen for full-text assessment. Articles were screened using predetermined inclusion and exclusion criteria. 21 articles were included in the qualitative assessment. Descriptive analysis was performed for numeric parameters using mean ± standard deviation. Six types of guide systems were used in the included articles. The commonest guide system was SimPlant (45.64%) followed by NobleGuide (23.00%). The pooled mean angle deviation, global coronal deviation, and global apical deviation were 3.43 mm (95% CI = 2.96, 3.90), 1.16 mm (95% CI = 0.98, 1.24) and 1.35 mm (95% CI = 1.11, 1.59), respectively. The maximum mean(SD) of angle deviation, global coronal deviation, and global apical deviation happened in Stent Cad 4.1(1.86) degrees, NobleGuide 1.86(0.56) mm, and OnDemend3d 1.56(1.48) mm, respectively.Although a final statement could not be made on which system is better, it is certain that the software affects the deviation and could be as important as the implant itself. Clinical significanceThe choice of guide systems used for the production of static guide systems which was studied in this article could affect the accuracy of the implant placement procedure.

Comparative accuracy of cone-beam CT and conventional multislice computed tomography for real-time navigation in zygomatic implant surgery.

Cone-beam computed tomography (CBCT) and conventional multislice CT (MSCT) are both used in zygomatic implant navigation surgery but the superiority of one technique versus the other remains unclear. This study compared the accuracy of CBCT and MSCT in zygomatic implant navigation surgery by calculating the deviations of implants. Patients with severely atrophic maxillae were classified into two groups according to the use of CBCT- or MSCT-guided navigation system. The entry and apical distance deviation, and the angle deviation of zygomatic implants were measured on fused operation images. A linear effect model was used for analysis, with statistical significance set at P < .05. A total of 72 zygomatic implants were inserted as planned in 23 patients. The comparison of deviations in CBCT and MSCT groups showed a mean (± SD) entry deviation of 1.69 ± 0.59 mm vs 2.04 ± 0.78 mm (P = .146), apical deviation of 2 ± 0.68 mm vs 2.55 ± 0.85 (P < .001), and angle deviation of 2.32 ± 1.02° vs 3.23 ± 1.21° (P = .038). Real-time zygomatic implant navigation surgery with CBCT may result in higher values for accuracy than MSCT.

Does a fully digital workflow improve the accuracy of computer-assisted implant surgery in partially edentulous patients? A systematic review of clinical trials.

Accurate implant placement is essential in reducing post-treatment complications and in ensuring a successful treatment outcome. To compare the accuracy of fully-guided static computer-assisted implant surgery (s-CAIS) using partially- and fully-digital workflows. Electronic and manual literature searches were performed to collect evidence concerning the accuracy of fully-guided s-CAIS procedures utilizing tooth-supported guides. Quantitative analysis was conducted to evaluate the accuracy of partially- and fully-digital workflows, and survival rates and complications were qualitatively analyzed. Thirteen studies, including 6 randomized controlled trials and 7 prospective clinical studies, were selected for quantitative and qualitative synthesis. A total of 669 implants in 325 patients using s-CAIS were available for review. Meta-analysis of the accuracy revealed a total mean angular deviation of 2.68° (95% CI: 2.32°-3.03°); mean global coronal deviation of 1.03 mm (95% CI: 0.88-1.18 mm); mean global apical deviation of 1.33 mm (95% CI: 1.17-1.50 mm); and mean depth deviation of 0.59 mm (95% CI: 0.46-0.70 mm). Minimal differences were found between the two different workflows. Few complications were reported, and survival rates were between 97.8% to 100% (range of follow-up: 12 to 24 months) in the available studies. Similar accuracy is obtained when implants are placed in partially edentulous patients using fully-guided s-CAIS, independently of the workflow utilized.

Static computer-aided, partially guided, and free-handed implant placement: A systematic review and meta-analysis of randomized controlled trials.

To analyze the outcomes of static computer-aided implant placement (sCAIP) compared to partially guided (PGIP) and free-handed (FHIP) implant placement. This study was registered in PROSPERO (CRD42019131397). A comprehensive literature search was performed by two independent examiners. Only randomized controlled trials (RCTs) were selected. Treatment modalities included sCAIP, PGIP, and FHIP. Data pertaining to the outcomes of interest were extracted. Random-effects meta-analyses were feasible for a subset of outcomes. From an initial list of 2,870 records, fourteen articles for a total of ten RCTs were selected. Data from 7 of these studies allowed for the conduction of three meta-analyses comparing accuracy of implant placement across modalities. Survival rate up to 12months post-loading was high (>98%) and comparable between treatments (low-quality evidence). No tangible differences in terms of patient perception of intra- or postoperative discomfort were observed (low-quality evidence). Quantitative analyses revealed significantly lower angular (MD=4.41°, 95% CI 3.99-4.83, p<.00001), coronal (MD=0.65mm, 95% CI 0.50-0.79, p<.00001), and apical (MD=1.13mm, 95% CI 0.92-1.34, p<.00001) deviation values for sCAIP as compared to FHIP (8 studies, 383 patients, 878 implants, high-quality evidence). A similar discrepancy, in favor of sCAIP, was observed for angular deviation only as compared to PGIP (MD=2.11°, 95% CI 1.06-3.16, p<.00001). sCAIP is associated with superior accuracy compared to PGIP and FHIP.

Comparison of the Accuracy of Implant Position Using Surgical Guides Fabricated by Additive and Subtractive Techniques.

To evaluate the accuracy of implant position using surgical guides fabricated by additive and subtractive techniques. A partially edentulous standardized mandibular implant model with different bone densities and soft tissue was duplicated and a diagnostic wax-up was performed for the #30 area. A reference radiographic guide was fabricated and cone beam computed tomography (CBCT) was made with the reference radiographic guide in place. A surgical guide was designed using BlueSky Plan 4 software and a reference implant was placed in the #30 region. The STL file of the surgical guide was exported and specimens (n = 15) were fabricated by two different techniques: additive (3D printing) and subtractive (milling). The standardized mandibular model was surface-scanned and duplicated with printed dental model resin (n = 30). Each surgical guide was used to place an implant in thirty duplicate printed models. Differences in implant position as compared to the reference were measured from digital scans with scan bodies in place. The angular deviations, differences in depth, coronal and apical deviations were measured using GeoMagic Control X software. Results were analyzed by Wilcoxon-Mann-Whitney test and PERMANOVA (Permutational Multivariate Analysis of Variance). Intraclass correlation was used to assess measurement reproducibility with Bonferroni adjustment for multiple testing as needed (α = 0.05). There were no significant differences in accuracy of implant placement using guides fabricated using additive vs subtractive techniques. The mean angular deviations between the reference and actual position of implant in mesio-distal cross-section were 0.780 ± 0.80° for printed group and 0.77 ± 0.72° for the milled group. The differences in bucco-lingual cross-section were 1.60 ± 1.22° in in printed group and 1.77 ± 0.76° in the milled group. The differences in depth (mm) were measured at the top of the scan body at four locations: mesial, distal, buccal and lingual. The mean differences in depth for the group that used printed surgical guides were (mesial) 0.37 ± 0.29 mm, (distal) 0.32 ± 0.23 mm, (buccal) 0.24 ± 0.23 mm, and (lingual) 0.25 ± 0.17 mm. The mean differences in depth for the group that used milled surgical guides were (mesial) 0.51 ± 0.33 mm, (distal) 0.40 ± 0.32 mm, (buccal) 0.22 ± 0.23 mm, and (lingual) 0.23 ± 0.12 mm in those four aspects, respectively. The mean coronal deviation showed 0.32 mm in the printed group and 0.27 mm in the milled group. For the apical deviation, the results of this study showed mean apical deviation 0.84 mm in the printed group and 0.80 mm in the milled group. Results indicate that 3D-printed surgical guides are statistically as accurate as milled guides for guided-implant surgery with the benefits of high accuracy, ease of fabrication, less waste compared to subtractive techniques, and reduction of laboratory time thereby increasing cost-effectiveness.

Is there a learning curve in static computer-assisted implant surgery? A prospective clinical study

Static computer-assisted surgery (s-CAS) has been introduced to improve the results of implantology. A prospective cohort study was conducted following the STROBE guidelines to determine the presence of a learning curve in s-CAS. Six partially and six totally edentulous patients were treated by two surgeons experienced in implantology but completely inexperienced in s-CAS. Preoperative and postoperative computed tomography scans were matched to assess coronal, apical, and angular deviation and the positioning error. The accuracy data were used to evaluate the learning curve. Fifty-six implants were inserted. In partially and totally edentulous patients, the mean (range; standard deviation) coronal deviation was 0.87 (0.34–1.27; 0.35) and 1.24 (0.72–2.67; 0.79); the mean apical deviation was 1.13 (0.48–1.63; 0.39) and 1.52 (0.88–3.84; 1.15); the mean angular deviation was 2.63 (1.89–4.50; 0.98) and 3.59 (1.69–6.30; 1.65); and the mean positioning error was 0.80 (0.32–1.25; 0.35) and 1.14 (0.35–2.56; 0.77), respectively. A typical ‘learning curve’ effect was not identified for s-CAS.