Digital vs Conventional Full-Arch Implant Impressions: A Retrospective Analysis of 36 Edentulous Jaws.

PURPOSE: There is a paucity of comparative clinical studies assessing the accuracy of full-arch digital scans versus conventional implant impressions. The aim of this retrospective study was to compare the three-dimensional (3D) deviations between full-arch digital scans and conventional implant impressions for edentulous maxillae and mandibles. MATERIALS AND METHODS: Twenty-seven patients (36 edentulous jaws) were treated with one-piece, screw-retained implant-supported fixed complete dental prostheses (IFCDPs). Twenty-one jaws were maxillary, and 15 were mandibular. Full-arch conventional impressions and intraoral digital scans with scan bodies and an intraoral scanner had been taken during the impression phase. Following verification of the conventional stone casts, the casts were digitized. The generated standard tessellation language (STL) files from both impression techniques were merged and analyzed with reverse engineering software. The primary aim was to evaluate the accuracy between conventional and digital full-arch scans, while the effect of the edentulous jaw in 3D accuracy was the secondary aim. RESULTS: The cumulative 3D (mean ± SD) deviations between virtual casts from intraoral full-arch digital scans and digitized stone casts generated from conventional implant impressions were found to be 88 ±24 µm. In the maxillary group, the mean ± SD 3D deviation was 85 ±25 µm, compared to 92 ±23 µm for the mandibular group (p = 0.444). CONCLUSION: The 3D implant deviations found between the full-arch digital and conventional impressions lie within the clinically acceptable threshold. No statistically significant difference was identified between maxillary and mandibular jaws in terms of 3D deviations.

Prosthesis accuracy of fit on 3D-printed casts versus stone casts: A comparative study in the anterior maxilla.

OBJECTIVE: To compare in vitro the accuracy of fit of a reference prosthesis seated on three-dimensional (3D) printed casts generated from digital implant scans vs stone casts made by conventional implant impressions. MATERIAL AND METHODS: A partially edentulous maxillary master cast with two internal connection implants was generated, while a reference implant-supported prosthesis was fabricated. Conventional splinted open-tray impressions were taken to create stone casts (n = 10) (control group). A digital scan was taken of the master cast using a white light intraoral optical scanner (IOS) (TRIOS, 3Shape), and a Standard Tessellation Language (STL) file was obtained. Four 3D printers were used to print the casts (n = 10 from each 3D printer): Straumann® P30+, Varseo S, Form 3b+and M2 Carbon. Accuracy of fit of the reference prosthesis on all control and test casts was assessed using the screw resistance test and radiographic test. Additionally, all casts were digitized using the same IOS, and the STL files were superimposed to the master cast STL file (reference) to evaluate the 3D accuracy with inspection Geomagic Control software using the root-mean-square (RMS) error. RESULTS: The reference prosthesis presented with clinically acceptable fit on all casts. The highest median RMS error was found in the stone cast group (94.6 µm) while the lowest median was in the M2 Carbon group (46.9 µm). The Kruskal-Wallis test revealed a statistically significant difference between the groups (p < 0.001). For post hoc comparisons, Dunn's test with the Holm-Bonferroni correction resulted in a statistically significant difference in four tests, with M2 Carbon exhibiting lower RMS error than the stone cast (p < 0.001) and P30+ (p < 0.001) groups, Form 3b exhibiting lower RMS error than the stone cast (p < 0.001) group, and Varseo S exhibiting lower RMS error than the stone cast (p = 0.006) group. CONCLUSION: Using the screw-resistance test and radiographic assessment, the reference prosthesis fit presented with clinically acceptable accuracy of fit on all casts. Printed casts from 3 different printers demonstrated statistically significant lower 3D deviations than stone casts generated using a conventional implant impression for the present partially edentulous scenario with two implants, but this did not affect prosthesis fit. CLINICAL SIGNIFICANCE: Even though there were 3D deviations between the master cast and all control and test casts generated from conventional impressions and digital scans respectively, the reference prosthesis presented with accurate fit on all casts. This indicates that there is a threshold for clinically acceptable accuracy of fit and that 3D-printed casts may be used as definitive master casts to fabricate implant-supported fixed dental prostheses for the partially edentulous anterior maxilla.

Comparison of maxillary tuberosity and palatal donor sites for soft tissue augmentation at implant placement: A pilot controlled clinical study.

PURPOSE: To compare the outcomes of soft tissue augmentation during one-stage implant placement using grafts harvested from the hard palate or the maxillary tuberosity. MATERIALS AND METHODS: In this pilot controlled clinical study, non-smoking adults with a single missing tooth in the anterior or premolar region and adequate ridge dimensions for implant placement were enrolled. Each received a single implant and connective tissue graft harvested either from the hard palate (n = 10) or the maxillary tuberosity (n = 10). Digital impressions were taken prior to treatment (T0) and then 2 and 12 months postoperatively (T1 and T2, respectively). The primary study outcome was changes in horizontal ridge dimension. Secondary outcomes included marginal bone level changes over time, pain levels in the first 2 postoperative weeks (W1 and W2) and pink aesthetic score and patient-reported outcome measures at T2. Data analysis included repeated measures analysis of variance for intergroup comparisons. RESULTS: The horizontal ridge dimension increased significantly in both groups (P ≤ 0.002) at all apico-coronal levels examined, with no significant intergroup differences. There was also no significant intergroup difference in marginal bone level changes (P = 0.376). The hard palate group experienced higher pain levels in the donor site compared to the tuberosity group at W1 (P = 0.023). The pink aesthetic score and patient-reported outcome measures were similar between groups at T2. CONCLUSIONS: Soft tissue augmentation during one-stage implant placement results in significant increases in the horizontal ridge dimension.

Accuracy of 3D Printed Implant Casts Versus Stone Casts: A Comparative Study in the Anterior Maxilla.

PURPOSE: To conduct an in vitro comparison of the amount of three-dimensional (3D) deviation of 3D printed casts generated from digital implant impressions with an intraoral scanner (IOS) to stone casts made of conventional impressions. MATERIAL AND METHODS: A maxillary master cast with partially edentulous anterior area was fabricated with two internal connection implants (Regular CrossFit, Straumann). Stone casts (n = 10) that served as a control were fabricated with the splinted open-tray impression technique. Twenty digital impressions were made using a white light IOS (TRIOS, 3shape) and the Standard Tesselation Language (STL) files obtained were saved. Based on the STL files, a digital light processing (DLP) and a stereolithographic (SLA) 3D printer (Varseo S and Form 2) were used to print casts (n = 10 from each 3D printer). The master cast and all casts generated from each group were digitized using the same IOS. The STL files obtained were superimposed on the master cast STL file (reference) to evaluate the amount of 3D deviation with inspection software using the root mean square value (RMS). The independent-samples Kruskal-Wallis test and Dunn's test with Bonferroni correction (for post hoc comparisons) were used for statistical analyses. RESULTS: The Varseo S group had the lowest median RMS value [77.5 µm (IQR = 91.4-135.4)], followed closely by the Conventional group [77.7 µm (IQR = 61.5-93.4)]. The Form 2 had the highest mean value [98.8 µm (IQR = 57.6-87.9)]. The independent-samples Kruskal-Wallis test revealed a significant difference between the groups (p = 0.018). Post hoc testing revealed a significant difference between Varseo S and Form 2 (p = 0.009). CONCLUSION: The casts generated from the Varseo S 3D printer had better 3D accuracy than did those from the Form 2 3D printer. Both the Varseo S group and the conventional stone casts groups had similar 3D accuracy.

Comparative analysis of dimensional alterations following extraction of maxillary molars using three-dimensional images' superimposition: a CBCT study.

The aims of this study were to (i) evaluate the bone alterations following maxillary molar extraction and (ii) identify the factors associated with bone alterations using a tomographic analysis. Cone Beam Computer Tomographies (CBCTs) of 17 subjects with 25 maxillary molars were analyzed, before and, in average, 12 months following extraction. Fifty CBCTs were segmented as 3D models that were used as reference for analysis. Cross-sectional planes were established to measure the dimensional changes in the vertical, horizontal aspects, and the area of the alveolar bone. Associations between root divergence, initial bone location related to the maxillary sinus, and the thickness of buccal and palatal bone at baseline was assessed using mixed-effect models. Overall, the average reduction in vertical bone height was 35.23% (2.61 ± 1.76 mm). The mean reduction of area of alveolar process and horizontal bone width were 18.89% (56.08 ± 44.23 mm2) and 65.10% (8.33 ± 4.51 mm), respectively. There was a marginal significant association between horizontal bone changes and the thickness of palatal bone (p = 0.05). The results of the present study indicated that following maxillary molar extraction, significant dimensional changes occur in both the vertical and horizontal directions. The vertical changes were mainly attributed to remodeling on the coronal aspect of the alveolar ridge and sinus pneumatization was rare.

Digital vs Conventional Implant Impressions: A Systematic Review and Meta-Analysis.

PURPOSE: To systematically review in vitro and clinical studies comparing quantitatively the 3D accuracy (global implant deviations) of digital vs conventional implant impressions for partially and completely edentulous patients. MATERIALS AND METHODS: Electronic and manual searches were conducted to identify in vitro and clinical studies, reporting on the 3D accuracy between digital and conventional implant impressions. Secondary outcomes were the effect of implant angulation, type of conventional impression technique, and type of intraoral scanner on the accuracy of implant impressions. RESULTS: The inclusion criteria were met by 9 in vitro studies and 1 clinical study reporting on completely edentulous impressions, while 6 in vitro and 2 clinical studies reported on partially edentulous impressions. Quantitative meta-analysis was performed for 5 completely edentulous and 6 partially edentulous studies. The studies exhibited high values for heterogeneity. A random effects model was conducted to estimate the effect size. Based on 5 in vitro studies on completely edentulous impressions, the mean 3D implant deviation between conventional and digital impressions was 8.20 µm (95% CI: -53.56, 37.15) and the digital impressions had nominally less deviation (p = 0.72). Based on 1 clinical and 5 in vitro studies on partially edentulous impressions, the mean 3D implant deviation between conventional and digital impressions was 52.31 µm (95% CI: 6.30, 98.33) and the conventional impressions had nominally less deviation (p = 0.03). Five in vitro and 2 clinical studies were not included in the quantitative analysis due to heterogeneity in the methodology. Implant angulation affected the accuracy in favor of the partially edentulous conventional impressions whereas the effect of different scanners was not statistically significant on the completely edentulous impressions (p = 0.82). CONCLUSIONS: Digital scans appear to have comparable 3D accuracy with conventional implant impressions based mainly on in vitro studies. However, clinical trials are recommended to investigate the clinical accuracy of digital scans and digitally fabricated interim or prototype prostheses, before digital implant scans can be recommended for routine clinical use.

Corrigendum: Artificial intelligence in dentistry: current applications and future perspectives.

The following amendments are made to the published article: Quintessence Int 2020;51(3):248-257; First published 4 February 2020; doi:10.3290/j.qi.a43952 Artificial intelligence in dentistry: current applications and future perspectives Yo-wei Chen, DDS, MSc/Kyle Stanley, DDS/Wael Att, DDS, Dr Med Dent, PhD.

Digital Workflow for Implant Rehabilitation with Double Full-Arch Monolithic Zirconia Prostheses.

The purpose of the present report is to illustrate a proof-of-concept protocol with the double digital scanning (DDS) technique for complete digital workflow in double full-arch implant rehabilitation. Two patients (4 restored arches) presented with hopeless dentitions and they were treated with a 4-appointment prosthodontic protocol and monolithic zirconia prostheses implementing a complete digital workflow. The outcomes are presented after clinical and radiographic observation for 2 years.

Digital Versus Conventional Full-Arch Implant Impressions: A Prospective Study on 16 Edentulous Maxillae.

PURPOSE: A prospective clinical study to compare for the first time the accuracy of digital and conventional maxillary implant impressions for completely edentulous patients. MATERIALS AND METHODS: Sixteen patients received maxillary implant supported fixed complete dentures. After the verification of the conventional final casts, the casts were scanned with a desktop (extraoral) scanner. Intraoral full-arch digital scans were also obtained with scan bodies and STL files. Extraoral and intraoral scans were superimposed and analyzed with reverse engineering software. The primary outcome measure was the assessment of accuracy between scans of the verified conventional casts and digital full-arch impressions. The secondary outcome was the effect of the implant number on the 3D accuracy of impressions with Spearman's rank correlation coefficient. RESULTS: The 3D deviations between virtual casts from intraoral full-arch digital scans and digitized final stone casts generated from conventional implant impressions were found to be 162 ± 77 µm. In the 4-implant group, 5-implant group, and 6-implant group the 3D deviations were found to be 139 ± 56 µm, 146 ± 90 µm, and 185 ± 81 µm, respectively. There was a positive correlation between increased implant number and 3D-deviations, but there was no statistically significant difference (p = 0.191). CONCLUSIONS: The 3D accuracy of full-arch digital implant scans lies within previously reported clinically acceptable threshold. Full-arch digital scans and a complete digital workflow in the fabrication of maxillary fixed complete dentures may be clinically feasible.

Artificial intelligence in dentistry: current applications and future perspectives.

Artificial intelligence (AI) encompasses a broad spectrum of emerging technologies that continue to influence daily life. The evolution of AI makes the analysis of big data possible, which provides reliable information and improves the decision-making process. This article introduces the principles of AI and reviews the development of AI and how it is currently being used. AI technology has influenced the health care field because of the need for accurate diagnosis and superior patient care. In order to understand the trend of AI in dentistry, electronic searching was carried out, combined with approaching individual companies to obtain the details of AI-based services. The current applications of AI in clinical dentistry were introduced and summarized. In the future, the AI-based comprehensive care system is expected to establish high-quality patient care and innovative research and development, facilitating advanced decision support tools. The authors believe that an innovative inter-professional coordination among clinicians, researchers, and engineers will be the key to AI development in the field of dentistry. Despite the potential misinterpretations and the concern of patient privacy, AI will continue to connect with dentistry from a comprehensive perspective due to the need for precise treatment procedures and instant information exchange. Moreover, such developments will enable professionals to share health-related big data and deliver insights that improve patient care through hospitals, providers, researchers, and patients.

Digital workflow: In vitro accuracy of 3D printed casts generated from complete-arch digital implant scans.

STATEMENT OF PROBLEM: Data on the accuracy of printed casts from complete-arch digital implant scans are lacking. PURPOSE: The purpose of this in vitro study was to compare the 3D accuracy of printed casts from a complete-arch digital implant intraoral scan with stone casts from conventional impressions. MATERIAL AND METHODS: An edentulous mandibular cast with 4 multiunit abutments with adequate anteroposterior spread was used as the master cast. Digital scans (n=25) were made by using a white light intraoral scanner (IOS). The generated standard tessellation language (STL) data sets were imported into a computer-assisted design (CAD) software program to generate complete-arch implant casts through 3D printing technology. The 25 printed casts and the mandibular master cast were further digitized by using a laboratory reference scanner (Activity 880; Smart Optics). These STL data sets were superimposed on the digitized master cast in a metrology software program (Geomagic Control X) for virtual analysis. The root mean square (RMS) error and the average offset were measured. RESULTS: When compared with the master cast, the printed casts had a mean ±standard deviation RMS error of 59 ±16 µm (95% CI: 53, 66). The maximum RMS error reached 98 µm. The average offsets were all negative, with a significant difference compared with zero (P<.001). CONCLUSIONS: The implant 3D deviations of the printed casts from complete-arch digital scans had statistically significant differences compared with those of the master cast but may still be within the acceptable range for clinical application.

Registration of patient-relevant references in edentulous jaws using intraoral scanners: simplification of the clinical procedure.

With the advancement of computer-aided design/computer-aided manufacturing (CAD/CAM) in dentistry, the use of digital technologies is being increasingly adopted by clinicians and laboratory technicians. Clinicians are using intraoral scanners (IOSs) more and more to perform computer-aided impressions. While these are mainly used to digitize dentate or partially edentulous jaws, it is feasible with a few of the available systems to scan edentulous jaws, with or without implants. To scan edentulous jaws, the registration and articulation of patient-relevant references and planes is difficult without the use of physical casts. The present article introduces simple yet effective methods to integrate individual interocclusal information during the intraoral scan procedure. The techniques described aim to simplify the digital registration procedure of edentulous jaws, with or without implants, and integrate patient-relevant information in the virtual articulator without the need to manufacture and articulate casts after the intraoral scan.

Complete digital workflow in prosthesis prototype fabrication for complete-arch implant rehabilitation: A technique.

During complete-arch digital implant scanning, one of the most technique-sensitive steps is the data registration and superimposition or matching of different surface geometry data sets because of the absence of fixed landmarks. This article describes a straightforward technique for facilitating the accurate superimposition or matching of surface scan files from digital scans for the fabrication of the prosthesis prototype with a complete digital workflow.