Use of the universal scan template to achieve a predictable optical impression: Preliminary data of a case series study in complete edentulous patients.

BACKGROUND: Full-arch IOS scan of edentulous areas rehabilitated with dental implants is nowadays still described as an unpredictable procedure. To improve the accuracy, a universal scan template (UST®) is proposed in this article. The clinician can easily assemble the template with a mechanical coupling, by matching the scan bodies with objects of known dimension characterized by specific markers. The UST® facilitates the scanning of an entire arch on scan bodies, reducing the learning curve, simplifying acquisition movements, shortening the scanning time, and drastically reducing the risk of distortions and aberrations of the scans. MATERIALS AND METHODS: In a case series study on 12 patients, the improvement in the accuracy of the scans with UST® was validated by comparing the STL files derived from scans with and without the guide in place. A titanium bar was produced from each optical impression. RESULTS: The bars obtained from the optical impressions taken without UST® were found to be nonpassive in the mouth in the majority of the cases. On the contrary with the use of UST® we obtained 12 passive prosthetic rehabilitations. CONCLUSIONS: The proposed solution may represent a valid method to improve the predictability of full arch optical impressions on implants.

Clinical accuracy of partially guided implant placement in edentulous patients: A computed tomography-based retrospective study.

OBJECTIVES: This retrospective study was intended to evaluate the clinical accuracy of partially guided template in guiding implant placement in edentulous patients. METHODS: A total of 120 implants were placed in 24 patients with at least one completely edentulous arch with a partially guided system. Based on CBCT data, a repeatable method was used to measure linear and angular deviations of implants at 3D level in Mimics medical software. The influence of supporting tissue and implant region on the accuracy was assessed, followed by the evaluation of direction of linear deviations in biologically vital areas. RESULTS: Linear deviations of all implants were 1.91 ± 0.68 mm, 1.47 ± 0.68 mm, and 1.02 ± 0.69 mm at apical, apical lateral, and apical vertical levels. When at the cervical, cervical lateral, and cervical vertical levels, the linear deviations were 1.53 ± 0.65 mm, 0.98 ± 0.53 mm, and 1.01 ± 0.69 mm, respectively. Angular deviation of all implants was 7.14 ± 3.41°. Implants guided by mucosa + tooth-supported templates showed higher linear deviations at apical vertical level (1.21 ± 0.72 mm vs. 0.86 ± 0.63 mm, p < .05) and cervical vertical level (1.18 ± 0.72 mm vs. 0.87 ± 0.63 mm, p < .05) than mucosa-supported templates, and implants in maxilla were found higher angular deviation than mandible (7.89 ± 3.61° vs. 6.29 ± 2.97°, p < .05). CONCLUSIONS: The partially guided template served as clinically viable surgical assistance in implant placement in edentulous patients. When using mucosa + tooth-supported template or placing implants in maxilla, more caution was required, especially in biologically vital areas.

Evaluation of accuracy between extraoral Gothic arch tracing and various other methods assessing horizontal condylar guidance angle in completely edentulous patients: A systematic review and meta-analysis.

Aim: The aim of this systematic review and meta-analysis was to determine the accuracy of different methods of measuring horizontal condylar guidance (HCG) angle in comparison with extraoral Gothic arch tracing for completely edentulous patients. Settings and Design: This was a systematic review and meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Materials and Methods: Two reviewers searched the EBSCOhost, Cochrane Library, and PubMed/MEDLINE databases and the Google Scholar search engine for in vivo studies, randomized controlled trials, cross-sectional studies, and quasi-experimental studies published from January 2005 to December 2022 on various other methods of determining HCG angle in completely edentulous patients compared with extraoral Gothic arch tracing method. Statistical Analysis Used: Meta-analysis was conducted from the reported quantitative data. Results: A total of 513 articles were obtained from different electronic databases, of which 22 studies were included for qualitative synthesis and 20 studies were included for meta-analysis. For the right side, a statistically significant difference was observed for panoramic radiograph (P < 0.05, pooled mean difference = 5.08 [2.17, 7]) and cephalogram (P < 0.05, pooled mean difference = 10.65 [8.81, 12.49]), whereas no statistically significant difference was observed for cone-beam computed tomography (CBCT) (P = 0.41, pooled mean difference = 4.39 [-6.10, 14.87]) and protrusive interocclusal wax record (P = 0.92, pooled mean difference = -0.45 [-9.62, 8.72]) as compared with extraoral Gothic arch tracing method. For the left side, a statistically significant difference was observed for panoramic radiograph (P < 0.05, pooled mean difference = 5.07 [1.95, 8.18]) and cephalogram (P < 0.05, pooled mean difference = 10.24 [8.65, 11.83]), whereas no statistically significant difference was observed for CBCT (P = 0.31, pooled mean difference = 4.05 [-3.74, 11.84]) and protrusive interocclusal wax record (P = 0.72, pooled mean difference = -1.21 [-7.86, 5.43]) as compared with extraoral Gothic arch tracing method. Conclusion: The cephalogram and panoramic radiograph obtained higher HCG angles in completely edentulous patients than extraoral Gothic arch tracing.

Virtual occlusal records acquired by using intraoral scanners: A review of factors that influence maxillo-mandibular relationship accuracy.

PURPOSE: This review aims to provide a comprehensive summary of how much progress has been made in the field of virtual occlusal records (VOR) obtained with intraoral scanners (IOSs), their accuracy, and what factors influence their accuracy. MATERIALS AND METHODS: An electronic search was performed in MEDLINE via PubMed and Scopus databases in February 2023. Eligible articles were clinical or in vitro studies evaluating the accuracy of virtual occlusal records with intraoral scanners in completely dentate and partially edentulous arches. RESULTS: Virtual occlusal records have shown promising results in terms of accuracy, with some studies reporting a high level of agreement with traditional methods. Key factors influencing the accuracy of VOR through intraoral scanners were identified which encompass multiple parameters such as scanner brands, imaging technology, scan quality, best-fit alignment, software algorithms, intermesh penetrations, and the number of sections and dimensions of the virtual occlusal record. In partially edentate areas, the lack of landmarks in the edentulous area compromises the accuracy of VOR, thus limiting the use of IOS in patients with missing teeth. CONCLUSION: Understanding and recognizing these influencing factors will increase the predictability and reliability of dental treatments completed by using digital workflows.  However, certain challenges need to be addressed which can influence its accuracy and limit its use in daily practice. Future research should focus on improving these factors to enhance the clinical applicability of virtual occlusal records.

The accuracy of dynamic computer assisted implant surgery in fully edentulous jaws: A retrospective case series.

OBJECTIVES: To evaluate the accuracy of implant placement using a dynamic navigation system in fully edentulous jaws and to analyze the influence of implant distribution on implant position accuracy. MATERIALS AND METHODS: Edentulous patients who received implant placement using a dynamic navigation system were included. Four to six mini screws were placed in the edentulous jaw under local anesthesia as fiducial markers. Then patients received CBCT scans. Virtual implant positions were designed in the planning software based on CBCT data. Under local anesthesia, implants were inserted under the guidance of the dynamic navigation system. CBCTs were taken following implant placement. The deviation between the actual and planned implant positions was measured by comparing the pre- and postsurgery CBCT. RESULTS: A total of 13 edentulous patients with 13 edentulous maxillae and 7 edentulous mandibles were included, and 108 implants were placed. The average linear deviations at the implant entry point and apex were 1.08 ± 0.52 mm and 1.15 ± 0.60 mm, respectively. The average angular deviation was 2.85 ± 1.20°. No significant difference was detected in linear and angular deviations between the maxillary and mandibular implants, neither between the anterior and posterior implants. CONCLUSIONS: The dynamic navigation system provides high accuracy for implant placement in fully edentulous jaws, while the distribution of the implants showed little impact on implant position accuracy.

Comparative Evaluation of the Horizontal Condylar Guidance Using Protrusive Interocclusal Records, OPG, and CBCT in Edentulous Patients: An In Vivo Study.

AIMS: A clinical study to compare the horizontal condylar guidance using protrusive interocclusal records, orthopantomography (OPG), and cone-beam computed tomography (CBCT) in edentulous patients. SUBJECTS AND METHODS: Thirty-six edentulous subjects were selected as per predetermined criteria. Horizontal condylar guidance was recorded using protrusive interocclusal records (PIR), OPG, and CBCT for each patient. The PIR were obtained using extraoral Gothic arch tracers to program the Hanau articulator. The horizontal condylar guidance angles (HCGAs) were digitally constructed using appropriate software along the posterior slope of articular eminence for all radiographs. The collected data were recorded, tabulated, and statistically analyzed. RESULTS: The condylar guidance angle values were tested for significance to compare the different angles. The correlation of HCGA measurements on both sides between the three groups was analyzed. The PIR and OPG methods (p = 0.001), as well as the OPG and CBCT methods (p = 0.001), show substantial differences on both sides. On the contrary, the PIR and CBCT methods did not differ significantly (p = 0.11). CONCLUSION: Cone-beam computed tomography is as reliable and accurate as the clinical method. A significant correlation exists between the clinical method and CBCT. It can be used as a dependable adjunct to the clinical method of HCGA measurement. CLINICAL SIGNIFICANCE: Cone-beam computed tomography can overcome the shortcomings of the conventional clinical methods to determine the accurate horizontal condylar guidance angulation measurement. It is safer with minimum discomfort and wastage of time for the patients.

The Reverse Scan Body Protocol: Completing the Digital Workflow.

Recently developed extraoral techniques have allowed for an alternative approach for the digital acquisition of implant positions in fully edentulous patients. The "reverse scan body protocol" digitally simulates the traditional back-pouring technique long utilized in analog workflows. This article presents two cases in which an extraoral scanning technique was used to capture implant positions, design a prototype, and fabricate the definitive monolithic zirconia full-arch prosthesis.

Evaluation of the accuracy of intraoral scanners for complete-arch scanning: A systematic review and network meta-analysis.

OBJECTIVES: This network meta-analysis (NMA) aimed to compare the complete-arch scanning accuracy of different intraoral scanners (IOSs) to that of reference standard tessellation language (STL) files. DATA: Studies comparing the trueness and precision of IOS STL files with those of reference STL scans for different arch types (dentate, edentulous, completely edentulous with implants, and partially edentulous with implants) were included in this study. SOURCES: An electronic search of five databases restricted to the English Language was conducted in October 2021. STUDY SELECTION: A total of 3,815 studies were identified, of which 114 were eligible for inclusion. After study selection and data extraction, pair-wise comparison and NMA were performed to define the accuracy of scanning for four arch subgroups using four outcomes (trueness and precision expressed as mean absolute deviation and root mean square values). Cochrane guidelines and the QUADAS-2 tool were used to assess the risk of bias. GRADE was used for certainty assessment. RESULTS: Fifty-three articles were included in this NMA. Altogether, 26 IOSs were compared directly and indirectly in 10 network systems. The accuracy of IOSs scans were not significantly different from the reference scans for dentate arches (three IOSs), edentulous arches (three IOSs), and completely edentulous arches with implants (one IOS). The accuracy of the IOSs was significantly different from the reference scans for partially edentulous arches with implants. Significant accuracy differences were found between the IOSs, regardless of clinical scenarios. CONCLUSIONS: The accuracy of complete-arch scanning by IOSs differs based on clinical scenarios. CLINICAL SIGNIFICANCE: Different IOSs should be used according to the complete arch type.

Enhancing intraoral scanner accuracy using scan aid for multiple implants in the edentulous arch: An in vivo study.

OBJECTIVES: Intraoral scans of multiple implants in the edentulous arch are challenged by the absence of a distinct surface morphology between scan bodies. A scan aid was applied in such situation and evaluated for intraoral scanning accuracy in vivo. MATERIALS AND METHODS: 87 implants in 22 patients were scanned with scan aid (SA) and without scan aid (NO) using two different intraoral scanners (CS3600 [CS] and TRIOS3 [TR]). Master casts were digitized by a laboratory scanner. Virtual models were superimposed using an inspection software and Linear deviation and precision were measured. Statistical analysis was performed using linear mixed models (α = .05). RESULTS: Total mean linear deviation within the CS group was 189 µm without scan aid and 135 µm when using the scan aid. The TR group's total mean deviation was 165 µm with and without a scan aid. Significant improvement with scan aid was observed for the CS group (p = .001), and no difference was found in the TR group. 96% of scan bodies were successfully scanned in the TR-SA group compared to 86% for the TR-NO group, 83% for the CS-SA, and 70% for the CS-NO group, respectively. CONCLUSIONS: The evaluated scan aid improved linear deviation compared to unsplinted scans for the CS group but not for the TR group. These differences could originate from different scanning technologies used, active triangulation (CS) and confocal microscopy (TR). The scan aid improved the ability to recognize scan bodies successfully with both systems, which could have a favorable clinical impact overall.

Effect of the number and distribution of fiducial markers on the accuracy of robot-guided implant surgery in edentulous mandibular arches: An in vitro study.

OBJECTIVES: Robot-guided implant placement based on the screw marker-assisted registration technique has been applied in dentistry. This study aimed to identify the optimal number and distribution of fiducial markers for robot-guided implant placement in edentulous mandibular phantoms. METHODS: Four implants were digitally planned and placed in edentulous mandibular phantoms under robotic guidance. Different numbers of fiducial markers (3, 4, 5, or 6) and distribution patterns (dispersed or localized) were used to register the robotic system. Platform, apex, and angular deviations were measured between the planned and actual implant positions using different numbers and distributions of fiducial markers. RESULTS: Inserting six fiducial markers resulted in optimal implant position accuracy at the platform (0.53 ± 0.19 mm) and apex (0.59 ± 0.2 mm) deviations. However, the angular deviation did not differ significantly between different numbers of fiducial markers. Furthermore, the implant position accuracy did not differ significantly between the dispersed and localized distributions of fiducial markers. CONCLUSION: In robot-guided implant placement for edentulous mandibular arches, the insertion of six fiducial markers significantly increases the implant placement accuracy. CLINICAL SIGNIFICANCE: The findings of this in vitro study may serve as a reference for clinicians to determine the optimal placement of fiducial markers and to facilitate the clinical application of robot-guided systems for implant placement in edentulous patients. Further clinical studies are necessary to confirm these findings.

Effect of additional reference objects on accuracy of five intraoral scanners in partially and completely edentulous jaws: An in vitro study.

STATEMENT OF PROBLEM: The effect of additional reference objects on the accuracy of different intraoral scanners for partially and completely edentulous patients has not been investigated sufficiently. PURPOSE: The purpose of this in vitro study was to evaluate the effect of an additional reference object in the form of additional artificial landmarks on the trueness and precision of different intraoral scanners in partially and completely edentulous areas. MATERIAL AND METHODS: Partially and completely edentulous models with 2 and 4 implants (BLT, RC, Institut Straumann AG), respectively, were used in the study. For the digital scan, scan bodies (CARES Mono Scanbody) were attached, and reference data obtained by using industrial scanners. Ten digital scans of the same model were made with each intraoral scanner: PRIMESCAN, TRIOS 3, TRIOS 4, Carestream 3600, and Medit. Then, additional artificial landmarks were attached, and 10 more intraoral scans were made with each device. Computer-aided design files of the scan bodies were aligned to obtain 3-dimensional surfaces with reference and test scanners. Trueness and precision of distance, angulations, and vertical shift between scan bodies were estimated. The Mann-Whitney Wilcoxon or Student 2-sample t test was applied to estimate statistically significant differences between groups (α=.05). RESULTS: In the partially edentulous model, distance trueness mean ±standard deviation values ranged from -46.7 ±15.4 µm (TRIOS 3) to 392.1 ±314.3 µm (Medit) in models without additional artificial landmarks. When additional artificial landmarks were applied, trueness of distance mean ±standard deviation values ranged between -35 ±13 µm (TRIOS 4) and 117.7 ±232.3 µm (CARESTREAM). Trueness mean ±standard deviation values of angulation varied from -0.0 ±0.5 degrees (CARESTREAM) to 0.2 ±0.0 degrees (PRIMESCAN) without additional artificial landmarks and from 0.0 ±0.2 degrees (TRIOS 3) to 0.4 ±0.5 degrees (CARESTREAM) with additional artificial landmarks. Vertical shift trueness measurements varied from -108 ±47.1 µm (TRIOS 4) to 107.2 ±103.5 µm (Medit) without additional artificial landmarks and from -15.0 ±45.0 µm (CARESTREAM) to -86.9 ±42.1 µm (TRIOS 4) with additional artificial landmarks. The additional artificial landmark technique improved the trueness of all measured parameters for the 5 tested intraoral scanners. No statistically significant differences were found among models with or without additional artificial landmarks, except for Medit in all parameters and PRIMESCAN in angle measurements (P<.05). The best precision for distance was found with TRIOS 3 and with PRIMESCAN for angulation and vertical shift. Larger deviations were observed in the completely edentulous situation. The effect of additional artificial landmarks was limited when the accuracy parameters of digital scans were considered. CONCLUSIONS: Scans with and without additional artificial landmarks of partially edentulous conditions scanned by any of the intraoral scanners tested did not influence precision and trueness, except for Medit i500 in the distance and vertical shift parameters and CARESTREAM3600 in vertical shift. Precision and trueness of digital scans of completely edentulous areas were affected, except for Medit i500 for distance, PRIMESCAN and TRIOS 4 for angle, and all systems except TRIOS 4 for vertical shift precision.

Factors that influence the accuracy of intraoral scanning of total edentulous arches rehabilitated with multiple implants: A systematic review.

STATEMENT OF PROBLEM: The direct digitalization of completely edentulous arches rehabilitated with multiple implants still represents a limitation regarding obtaining accurate images for prosthetic purposes. PURPOSE: The purpose of this systematic review was to present the factors that may influence the accuracy of intraoral scanning of completely edentulous arches. MATERIAL AND METHODS: This review was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria and registered with International Prospective Register of Systematic Reviews (PROSPERO) (CRD42020171021). Three examiners performed an electronic search in the Medline/PubMed, Cochrane Library, Scopus, and Web of Science databases for articles published up to January 2021. RESULTS: The electronic search resulted in 11 498 studies. After removing duplicates, 11 347 studies remained. Twelve studies were selected (10 in vitro and 2 in vivo) according to the eligibility criteria. Several factors were found to influence the performance of intraoral scanners (Carestream Dental and TRIOS, 3Shape presented the best results), the intraoral scanning technique (Promoting physical paths that join the digitization bodies can increase the accuracy of transferring the position of the implants), environmental conditions (temperature: 20 °C to 21 °C, air pressure: 750 to 760 ±5 mmHg, air humidity: 45%, angle and distance between the implants: up to 15 degrees and 16 to 22 mm, and the material of the scan body: PEEK more accurate). CONCLUSIONS: The accuracy of the intraoral scanning of completely edentulous arches is affected by factors such as the type of intraoral scanner, scanning technique, environmental conditions, angle and distance between implants, and material of the scan bodies.

A fully digital protocol to provide a fixed interim complete denture for immediate loading for a completely edentulous patient: A dental technique.

Complete arch immediate-loading implant-supported prostheses can represent a major challenge for the patient and the dental team. Obtaining stable references and an accurate occlusal record after implant placement to provide an interim prosthesis is a difficult task and can deviate from the initial treatment plan. The described technique presents a fully digital protocol to provide an immediate complete arch implant-supported fixed interim prosthesis for edentulous patients by making postoperative cone beam computed tomography and intraoral digital scans that correlate with the previous plan.

Comparison of the accuracy of implant position among freehand implant placement, static and dynamic computer-assisted implant surgery in fully edentulous patients: a non-randomized prospective study.

The optimal implant position is a critical factor for long-term success in fully edentulous patients. Implants can be placed through conventional freehand, static computer-assisted implant surgery (CAIS), or dynamic CAIS protocols, but at present there is very limited clinical evidence on their accuracy in fully edentulous patients. This study was performed to evaluate the accuracy of implant placement using three protocols in fully edentulous patients. Thirteen patients received 60 implants with the freehand (n = 20), static CAIS (n = 20), or dynamic CAIS (n = 20) protocol. Postoperative cone beam computed tomography was utilized to evaluate the accuracy of implant placement in relation to the planned optimal position. The data were analysed by ANCOVA followed by Bonferroni analysis. The mean angular deviation (standard deviation) in the freehand, static CAIS, and dynamic CAIS groups was 10.09° (4.64°), 4.98° (2.16°), and 5.75° (2.09°), respectively. The mean three-dimensional deviation (standard deviation) at the implant platform in the freehand, static CAIS, and dynamic CAIS groups was 3.48 (2.00) mm, 1.40 (0.72) mm, and 1.73 (0.43) mm, while at the implant apex it was 3.60 (2.11) mm, 1.66 (0.61) mm, and 1.86 (0.82) mm, respectively. No difference in terms of accuracy was found between static and dynamic CAIS; both demonstrated significantly higher accuracy when compared to the freehand protocol in fully edentulous patients.

Superimposition of intraoral scans of an edentulous arch with implants and implant-supported provisional restoration, implementing a novel implant prosthetic scan body.

Purpose To describe a technique utilizing a novel prosthetic scan body, that assists the accurate merging of multiple scans (intra- and extraoral) of the interim prosthesis and edentulous arch with dental implants, during rehabilitation with a fixed implant-supported prosthesis.Methods Intraoral scanning (Trios 3, 3Shape) of an interim implant-supported prosthesis was performed, subsequently followed by another scan, using five scan bodies, placed onto the implant abutments (SRA, Bone level, Straumann AG). Successively, the newly designed prosthetic scan bodies were attached to the abutment copings of the interim prosthesis, for extraoral scanning. Utilizing an implant library designed for the prosthetic scan body, the three scans were merged, providing all the necessary information for the digital design and fabrication of the fixed implant-supported prosthesis.Conclusions The described clinical technique enabled effective and accurate superimposition of intra- and extraoral scans of the implant prosthesis. Superimposed data, including that of the position of dental implants and anatomy of soft tissue, provided essential information for the fabrication of a definitive implant-supported prosthesis. The novel prosthetic scan bodies attached to the implant prosthesis, assisted in merging intra- and extraoral scans, thus facilitating the rehabilitation of maxillary and/or mandibular edentulous dental arches. Further research is required to assess the accuracy of the proposed technique.

A new proposal for improving the accuracy of intraoral scanning for partially edentulous residual ridge.

Purpose This study investigated the usefulness of a newly proposed intraoral scanning method, using markers that can be used directly in the oral cavity, in order to improve the accuracy of impression taking of the residual ridge for fabrication of removable partial dentures.Methods An intraoral scanner was used to scan a dental model of a partially edentulous mandibular arch (Kennedy Class I). As markers, pieces of dried pasta were used. The scanning operation was performed under three conditions. In Condition 1, scanning was performed on the remaining teeth and the residual ridge without markers. In Condition 2, scanning of the remaining teeth and residual ridge was performed with markers. In Condition 3, the markers were removed from the model used in Condition 2, and the residual ridge was scanned again. The scanning data of each condition was superimposed on the control data, and the shape error was calculated and compared among the conditions.Results There was a significant difference in trueness of the residual ridge before and after marker application. The application of markers improved the trueness, while maintaining precision. Re-scanning after removing the marker did not affect trueness between before and after re-scanning and the re-scanned region showed shape continuity with the surrounding region.Conclusions The present method using markers that can be used in the oral cavity was effective in improving the accuracy of impression taking at the residual ridge.

Trueness of intraoral scanning of edentulous arches: A comparative clinical study.

PURPOSE: To compare the accuracy of intraoral scanning (IOS) of the edentulous arch with the hybrid protocol of cast digitization (CD), and to investigate the effect of arch type and area on trueness. MATERIALS AND METHODS: Participants that were edentulous in both arches were recruited. Two impression protocols were used; the IOS as the test protocol with an IOS device (TRIOS 4; 3Shape, Denmark), and the CD as the control, including tracing compound (TRACING STICKS; Kemdent, UK) for border molding, polyvinyl siloxane (Hydrorise Monophase; Zhermack, Italy) for impression, and cast digitization with a laboratory scanner (ceramill® map400, AMANNGIRRBACH, Germany). Scanned files were exported to a 3D inspection software (Geomagic Control X; 3D Systems, NC) for trueness analysis. The CD file (reference file) for each participant was split into 2 areas; the dynamic area representing the mobile tissues at the peripheral border, and the static area representing the rest of the arch. Statistical analyses were performed with 1-sample t-test for the difference between CD and IOS protocols, paired sample t-test for the difference between the static and dynamic areas for each arch, and an independent sample t-test for the difference between the maxillary and mandibular arches for each area, with α = 0.05. Effect size was calculated with Cohen's d (d), with 0.2 as small, 0.5 as medium, and 0.8 as large. RESULTS: A total of 21 participants were included. The difference between the IOS and CD protocol was significant for all subset comparisons (p < 0.001, d: 2.5-6.2, large effect size). Dynamic areas had lower trueness in comparison with static areas (p < 0.001, d = 4.57, large effect size for the maxillary arch, p < 0.001, d = 3.96, large effect size for the mandibular arch). Mandibular arch had lower trueness in comparison with the maxillary arch (p < 0.001, d = 1.45, large effect size for the static areas, p = 0.009, d = 0.85, large effect size for the dynamic areas, p < 0.001, d = 1.71, large effect size for all areas). Color difference map showed marked positive deviation in the buccal dynamic areas of both arches, and nonmatching areas with evident overstretching. CONCLUSIONS: While the IOS of edentulous arches could be feasible for attached mucosa, providing a functional shape for the peripheral border remains a challenge, with a thinner and more outward border for the IOS in comparison with the CD protocol. The IOS of the mandibular arch is more difficult and has lower trueness in comparison with the maxillary arch.

The trueness of scans using one intraoral scanner in different partially edentulous conditions.

PURPOSE: To investigate the trueness of intraoral scanning in 8 commonly seen partially edentulous conditions. MATERIALS AND METHODS: A maxillary dentoform was modified into the 8 commonly seen partially edentulous conditions. Each modification was scanned with a laboratory desktop scanner. Each modification was then scanned 10 times (n = 10) with an intraoral scanner. All scans were exported as STL files and then imported into a surface matching software using the best-fit alignment method. The dimensional differences between the study STL files from the intraoral scanner were compared to the corresponding reference STL files. The measurements were calculated as the root mean square (RMS) and defined as the trueness of the intraoral scans. In addition to the RMS values, qualitative assessments were completed on the color maps. The color maps produced by the surface matching software were used to visualize the areas of deviation between scans from the intraoral scanner and their corresponding reference files. One-way analysis of variance (ANOVA), followed by pair-wise comparisons using Fisher's Protected Least Significant Difference were utilized to compare the differences between the groups in RMS values (α = 0.05). RESULTS: Partially edentulous condition significantly affected the trueness of the intraoral scans. Group 8 (Class IV) had significantly lower RMS (0.1878 ± 0.0455 mm) than all other groups (p < 0.001). Group 2 (Class II) and Group 7 (Class III modification I) are not significantly different from each other (Group 2: 0.5758 ± 0.0300 mm; Group 7: 0.5602 ± 0.0231 mm, p = 0.571), while they both had significantly higher RMS than all other groups (p < 0.001). The remaining groups showed the RMS values were within the range of 0.3001 ± 0.0891 mm (Group 6 - Class III with Long Edentulous Span) and 0.4541 ± 0.1039 mm (Group 1 - Class I). CONCLUSION: Different partially edentulous conditions affected the trueness of the scans generated from the selected intraoral scanner. Class IV edentulous condition had the highest intraoral scan trueness. It is unknown if RMS values are clinically significant, and the validity of using intraoral scans directly for PRDP fabrication will need further studies.

Assessment of thickness of roof of the glenoid fossa in dentate, edentulous, and partially edentulous subjects using cone beam computed tomography (CBCT) - a retrospective study.

OBJECTIVES: Studies have inferred a direct association between Temporomandibular joint disorders (TMD) and the integrity of the structures associated with it such as the Glenoid fossa thereby necessitating the requirement to measure the thickness of this oft ignored entity. This study was carried out to assess the thickness of the glenoid fossa roof in dentulous, edentulous, and partially edentulous subjects using archival Cone beam computed tomography (CBCT) images. METHOD: Analysis of CBCT data of 120 joints from 60 adult subjects without signs and symptoms of TMD was carried out. The scans were grouped based on the dental status as dentulous, edentulous, and partially edentulous and additionally into two sets as those below and above 40 years of age. The distance between the superior and inferior cortices of the glenoid fossa was measured indicating the thickness of the roof of the glenoid fossa in the coronal and sagittal planes, by three independent observers. Analysis of Variance (ANOVA) and Tukey's post hoc test were used to compare the association between the mean thickness of the glenoid fossa and the dentition status. A p ≤ 0.05 was considered to be significant. RESULTS: There was no significant association between the mean thickness of the glenoid fossa and the dentition of the study participants of all three groups, when assessed by the three observers, except the mean thickness on the right side in the sagittal section as measured by one observer. A thicker fossa was observed in edentulous subjects when compared to dentulous participants, and the difference was statistically significant (p = 0.035). CONCLUSION: The thickness of the roof of the glenoid fossa demonstrated no association with the dental status of the study participants and no age or sex related differences were noted.

Automated detection and labelling of teeth and small edentulous regions on cone-beam computed tomography using convolutional neural networks.

OBJECTIVE: To assess the accuracy of a novel Artificial Intelligence (AI)-driven tool for automated detection of teeth and small edentulous regions on Cone-Beam Computed Tomography (CBCT) images. MATERIALS AND METHODS: After AI training and testing with 175 CBCT scans (130 for training and 40 for testing), validation was performed on a total of 46 CBCT scans selected for this purpose. Scans were split into fully dentate and partially dentate patients (small edentulous regions). The AI Driven tool (Virtual Patient Creator, Relu BV, Leuven, Belgium) automatically detected, segmented and labelled teeth and edentulous regions. Human performance served as clinical reference. Accuracy and speed of the AI-driven tool to detect and label teeth and edentulous regions in partially edentulous jaws were assessed. Automatic tooth segmentation was compared to manually refined segmentation and accuracy by means of Intersetion over Union (IoU) and 95% Hausdorff Distance served as a secondary outcome. RESULTS: The AI-driven tool achieved a general accuracy of 99.7% and 99% for detection and labelling of teeth and missing teeth for both fully dentate and partially dentate patients, respectively. Automated detections took a median time of 1.5s, while the human operator median time was 98s (P<0.0001). Segmentation accuracy measured by Intersection over Union was 0.96 and 0.97 for fully dentate and partially edentulous jaws respectively. CONCLUSIONS: The AI-driven tool was accurate and fast for CBCT-based detection, segmentation and labelling of teeth and missing teeth in partial edentulism. CLINICAL SIGNIFICANCE: The use of AI may represent a promising time-saving tool serving radiological reporting, with a major step forward towards automated dental charting, as well as surgical and treatment planning.