Accuracy of complete-arch digital implant impression with intraoral optical scanning and stereophotogrammetry: An in vivo prospective comparative study

Objectives: To assess accuracy of intraoral optical scanning (IOS) and stereophotogrammetry (SPG), complete-arch digital implant impressions in vivo. Materials and Methods: Consecutive patients needing implant-supported screw-retained zirconia complete-arch fixed-dental prostheses (ISZ-FDP) were recruited. For each patient, three impressions were taken: IOS, SPG (tests), and open-tray plaster (reference). Linear (ΔX, ΔY, and ΔZ), three-dimensional (ΔEUC), and angular deviations (ΔANGLE) were evaluated and stratified according to scanning technology for each implant. Potential effects of impression device (IOS and SPG), arch (maxilla and mandible), and implant number (4 and 6) were evaluated through multivariable analysis. Significance level was set at.05. Results: A total of 11 complete arches (5 maxillae, 6 mandibles) in 11 patients were rehabilitated with ISZ-FDPs supported by 4 (n = 8) and 6 implants (n = 3). A total of 50 implants and 100 implant positions were captured by two investigated devices and compared to respective reference (mean ΔEUC IOS 137.2, SPG 87.6 μm; mean ΔANGLE 0.79, 0.38°). Differences between measurements (SPG-IOS) were computed for each implant, with negative values indicating better SPG accuracy. Significant mean ΔEUC difference of −49.60 μm (p =.0143; SD 138.15) and mean ΔANGLE difference of −0.40° (p <.0001; SD 0.65) were observed in favor of SPG. Multivariable analysis showed significant effect on ΔEUC (p =.0162) and ΔANGLE (p =.0001) only for impression devices, with SPG performing better. Conclusions: SPG experienced significantly higher linear and angular accuracy. No effect of type of arch or implant number was detected. Higher extreme deviations were experienced for IOS. SPG can be feasible for complete-arch digital impressions with caution, and rigid prototype try-in is recommended before screw-retained prosthesis manufacturing. © 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

Clinical performance of immediately placed and immediately loaded single implants in the esthetic zone: A systematic review and meta-analysis.

OBJECTIVES The aim of this study was to assess the following PIO question: In adult patients treated with an indication for single tooth extraction in the maxillary esthetic zone (15-25), what is the influence of an immediate implant placement and immediate loading protocol on the clinical performance (primary aim) and esthetic outcomes (secondary aim) focusing on investigations published after 2010. MATERIAL AND METHODS An electronic search in Medline (PubMed), the Cochrane Central Register of Controlled Trials, and EMBASE databases up to April 2022 was performed to identify clinical studies investigating the outcome of single implants subjected to immediate placement with immediate restoration/loading (Type 1A). RESULTS Sixty-three studies (10 randomized controlled trials, 28 prospective and 25 retrospective cohort studies) were included with a follow-up ranging from 12 to 96 months. One thousand nine hundred sixty-one implants reported survival rates of 99.2 (98.6-99.5) % at 1 year, 97.5 (95.9-98.4) % after 3 years, and 95.8 (93.3-97.4) % after 5 years; 1064 immediately loaded restorations presented survival rates of 98.9 (97.8-99.5) % after 1 year, 96.8 (93.6-98.4) % after 2 years, and 94.8 (89.6-97.4) % after 5 years. Comparing baseline to 12-month data using the Hedges' g effect size (95% CI), papilla height presented an overall effect size of -0.71 (-1.25, -0.1) mm, midfacial recession change of -0.15 (-0.66, 0.36) mm, and a 0.82 (0.37, 1.28) gain in PES. CONCLUSIONS Immediate implant placement and immediate loading can be considered a predictable and safe treatment option for single maxillary anterior restorations with adequate survival rates and favorable esthetics outcomes for up to 5 years

Selection criteria for immediate implant placement and immediate loading for single tooth replacement in the maxillary esthetic zone: A systematic review and meta-analysis.

OBJECTIVES The aim of this study was to review available evidence for Type 1A (immediate implant placement and immediate loading) of single tooth replacement in the maxillary esthetic zone. MATERIALS AND METHODS An electronic search was conducted utilizing the databases of MEDLINE, Embase, and Cochrane to identify publications reporting on the outcomes of Type 1A for single tooth replacement in the maxillary esthetic zone. The success and survival rates of the included articles were reported, which were further categorized according to the clinical criteria reported in Type 1A. Mean survival rates were univariately compared between risk groups and additionally between studies published before and since 2012 using bias-corrected and study size-weighed bootstrap tests. A study time-correcting meta-analysis was then performed to obtain an overall effect for the study pool. RESULTS A total of 3118 publications were identified in the search, with a total of 68 articles included. A mean number of implants per study were 37.2 and mean follow-up was 2.8 years. All the included studies utilizing Type 1A report highly selective inclusion and exclusion criteria. Univariate risk group comparison determined that studies before 2012 report a significantly lower mean survival rate (difference of -1.9 percentage points [PP], 95% CI: [-0.3, -4.0], p = .02), facial gap dimension had an impact on survival rates (+3.1 PP [0.2, 5.3] for width >2 mm, p = .04), as well as presence of endodontic infection (+2.6 PP [0.9, 5.1], p = .004). CONCLUSIONS Type 1A has a high survival rate in studies reporting strict patient and site selection criteria. Further research is required to assess esthetic and functional success with Type 1A treatments

Guided bone regeneration and abutment connection augment the buccal soft tissue contour: 3-year results of a prospective comparative clinical study

AIM: To test whether implant placement with simultaneous guided bone regeneration (GBR) differs from implant placement without GBR regarding the change in marginal mucosal contour. MATERIALS AND METHODS: In 28 patients, single implants were placed >4 months after tooth extraction. Eighteen implants were completely surrounded by native bone, and no bone augmentation was performed. At 10 implant sites, bone defects and thin bone plates were grafted with deproteinized bovine-derived bone mineral and covered with collagen membrane. Impressions were taken prior to implant placement (baseline), at 3 months before abutment connection, at 6 months immediately after crown insertion, at 1 year, and at 3 years. Models were optically scanned and 3D images were superimposed for the evaluation of mucosal contour changes at the mid-buccal aspect. The nonparametric Mann-Whitney U-test was applied to detect differences. RESULTS: From baseline to 6 months, horizontal contour change at the level 1 and 2 mm apical to the mucosal margin measured 0.65 ± 0.74 mm and 0.55 ± 0.56 mm at sites without GBR, and 1.92 ± 0.87 mm and 1.76 ± 0.70 mm at sites with GBR (P < 0.05). In the period from baseline to 1 year, the corresponding values amounted to 0.81 ± 0.67 mm and 0.60 ± 0.55 mm in the group without GBR, and to 1.81 ± 0.86 mm and 1.37 ± 0.62 mm in the group with GBR (P < 0.05). From baseline to 6 months, mucosal margin moved 0.16 ± 0.49 mm in the coronal direction in the group without GBR and 0.82 ± 0.65 mm in the group with GBR (P < 0.05). In the period from baseline to 1 year, vertical change of mucosal margin amounted to 0.64 ± 0.54 mm in the group without GBR and to 1.17 ± 0.53 mm in the GBR group (P < 0.05). From 1 to 3 years, the mucosal contours remained stable. CONCLUSIONS: Implant placement with simultaneous GBR resulted in more gain of buccal soft tissue contour in comparison with implant placement without GBR. Abutment connection increased the contour of the marginal mucosa at the augmented and the nonaugmented sites. GBR procedure contributed more to the contour gain than did the abutment connection. The augmented and the nonaugmented ridges exhibited stable peri-implant mucosal contour over a 3-year period

Titanium-zirconium narrow-diameter versus titanium regular-diameter implants for anterior and premolar single crowns: 3-year results of a randomized controlled clinical study.

AIM To test whether titanium-zirconium (Ti-Zr) 3.3 mm diameter implants perform differently from titanium (Ti) 4.1 mm diameter implants with respect to marginal bone level (MBL) and clinical parameters. MATERIAL AND METHODS Forty patients in need of a single-implant crown in the anterior or premolar regions were enrolled in two centres. Following random allocation, either a Ti-Zr or a Ti implant was inserted. Porcelain-fused-to-metal crowns were inserted 6 months after implantation. Implant survival, change in MBL, clinical parameters, change in mid-facial mucosa and papilla levels, and the occurrence of biological and technical complications were assessed at the 3-year follow-up. RESULTS At 3 years, 32 of the 40 included patients were examined (15 Ti, 17 Ti-Zr). There were no implant failures. From the implant placement to 3 years, the median change in mean MBL amounted to 0.21 mm (mean: -0.31) in the Ti group and 0.10 mm (mean: -0.40) in the Ti-Zr group. There were no significant differences between the groups with respect to the change in MBL, the change in mucosa levels, and the occurrence of complications. CONCLUSIONS Ti-Zr implants with 3.3 mm diameter used for the support of single crowns in the anterior and the premolar regions did not differ from Ti implants with 4.1 mm diameter regarding the clinical performance over a 3-year period. This article is protected by copyright. All rights reserved

An In-Vitro Evaluation of Articulation Accuracy for Digitally Milled Models vs. Conventional Gypsum Casts

With the advent of a digital workflow in dentistry, the inter-occlusal articulation of digital models is now possible through various means. The Cadent iTero intraoral scanner uses a buccal scan in maximum intercuspation to record the maxillomandibular relationship. This in-vitro study compares the occlusion derived from conventionally articulated stone casts versus that of digitally articulated quadrant milled models. Thirty sets of stone casts poured from full arch polyvinyl siloxane impressions (Group A) and thirty sets of polyurethane quadrant models milled from digital impressions (Group B) were used for this study. The full arch stone casts were hand-articulated and mounted on semi-adjustable articulators, while the digitally derived models were pre-mounted from the milling center based on the data obtained from the buccal scanning procedure. A T-scan sensor was used to obtain a bite registration from each set of models in both groups. The T-scan data derived from groups A and B were compared to that from the master model to evaluate the reproducibility of the occlusion in the two groups. A statistically significant difference of the contact region surface area was found on #11 of the digitally articulated models compared to the master. An analysis of the force distribution also showed a tendency for a heavier distribution on the more anterior #11 tooth for the digitally articulated models. Within the limitations of this study, the use of a digitally articulated quadrant model system may result in a loss of accuracy, in terms of occlusion, the further anteriorly the tooth to be restored is located. Care must be taken to consider the sources of inaccuracies in the digital workflow to minimize them for a more efficient and effective restorative process

Contour angle and peri‐implant tissue height: Two interrelated features of the implant supracrestal complex

Abstract Objectives Recent research has suggested the contour of the prosthesis and the vertical height of the peri‐implant mucosa as important parameters that can influence the long term health and stability of the peri‐implant tissue. In particular, overcontouring of the prosthesis has been correlated with an increased risk for peri‐implantitis, while reduced soft tissue height has been associated with marginal bone loss, recession, and other soft tissue complications. Although these two parameters have been investigated as independent in the current literature, clinical experience points toward a close interrelation between transmucosal tissue height and prosthesis contour angle. It is often found that a reduced vertical height of the implant supracrestal complex is the main reason for overcontouring of the prosthesis. At the same time, achieving a favorable contour of 30o or less is not possible unless the clinician has ensured an adequate vertical height of the soft tissue. The purpose of this short communication is to establish the relation between tissue vertical height and prosthesis contour by utilizing a theoretical geometry equation based on the Pythagorean theorem. In doing so, one can use the dimensions of the implant as well as those of the prosthesis at the mucosal margin to calculate the essential vertical height for achieving a favorable prosthesis contour. Conclusions As the treatment plan of the implant supracrestal complex is “top‐down,” in case of deficient vertical height, subcrestal placement of the implant should be considered to achieve a proper prosthesis contour

A systematic review of the clinical performance of CAD/CAM single-tooth restorations

PURPOSE: This systematic review sought to determine the long-term clinical survival rates of single-tooth restorations fabricated with computer-aided design/computer-assisted manufacture (CAD/CAM) technology, as well as the frequency of failures depending on the CAD/CAM system, the type of restoration, the selected material, and the luting agent. MATERIALS AND METHODS: An electronic search from 1985 to 2007 was performed using two databases: Medline/PubMed and Embase. Selected keywords and well-defined inclusion and exclusion criteria guided the search. All articles were first reviewed by title, then by abstract, and subsequently by a full text reading. Data were assessed and extracted by two independent examiners. The pooled results were statistically analyzed and the overall failure rate was calculated by assuming a Poisson-distributed number of events. In addition, reported failures were analyzed by CAD/CAM system, type of restoration, restorative material, and luting agent. RESULTS: From a total of 1,957 single-tooth restorations with a mean exposure time of 7.9 years and 170 failures, the failure rate was 1.75% per year, estimated per 100 restoration years (95% CI: 1.22% to 2.52%). The estimated total survival rate after 5 years of 91.6% (95% CI: 88.2% to 94.1%) was based on random-effects Poisson regression analysis. CONCLUSIONS: Long-term survival rates for CAD/CAM single-tooth Cerec 1, Cerec 2, and Celay restorations appear to be similar to conventional ones. No clinical studies or randomized clinical trials reporting on other CAD/CAM systems currently used in clinical practice and with follow-up reports of 3 or more years were found at the time of the search

Intraoral digital implant scans: Parameters to improve accuracy.

PURPOSE To report the means to maximize the predictability and accuracy of intraoral digital implant scans through the evaluation of operator and patient related factors. MATERIALS AND METHODS Collection of published articles related to factors that can decrease the scanning accuracy of intraoral digital implant scans was completed in 4 data sources: MEDLINE, EMBASE, EBSCO, and Web of Science. All studies related to variables that can influence the accuracy of intraoral digital implant scans obtained by using intraoral scanners (IOSs) were considered. These variables included ambient lighting, scanning pattern, implant scan body (ISB) design, techniques for splinting ISBs, arch location, implant position and inter-implant distance. RESULTS Among operator-related factors, ambient lighting conditions, scanning pattern, and ISB design (material, geometry, and retention design) can impact the accuracy of intraoral digital implant scans. It is unclear the optimal ISB for maximizing the IOSs accuracy; however, polymer ISB can wear with multiple reuse and sterilization methods. Among patient-related factors, additional variables should be considered, namely arch (maxillary vs mandibular arch), implant position in the arch, inter-implant distance, implant depth, and angulation. CONCLUSIONS Ambient lighting conditions should be established based on the IOS selected to optimize the accuracy of intraoral digital implant scans. The optimal scanning pattern may vary based on the IOS, clinical situation, and the number of implants. The optimal ISB design may vary depending on the IOS used. Metallic implant scan bodies are preferred over polymer ISB designs to minimize wear due to multiple use and sterilization distortion. Among patient-related factors, additional variables should be considered namely the arch scanned, implant position in the arch, inter-implant distance, implant depth and angulation. The impact of these factors may vary depending on the IOS selected. This article is protected by copyright. All rights reserved

Influence of the Posterior Mandible Ridge Morphology on Virtual Implant Planning.

PURPOSE The purpose of this study was to examine the anatomy of the mandibular posterior region to develop an anatomical categorization for implant-prosthodontic planning. MATERIALS AND METHODS Using cone beam computed tomography scans, 313 cross-sectional views of edentulous posterior mandibular sites were evaluated with respect to the anatomical ridge morphology. Virtual implant planning was performed, and the need for bone grafting was assessed. The level of complexity for planning implants in those positions was assessed. Sites were classified as straightforward, advanced, or complex sites based on the need for bone grafting. RESULTS Five well-defined cross-sectional configurations were observed: straight (53.6%), oblique (26.2%), s-shape (7.4%), hourglass shape (1.9%), and basal bone (10.8%). There was a statistically significant association between the ridge shape and the feasibility of placing an implant with or without bone grafting; the straight and oblique ridge shapes were more likely to be associated with a favorable anatomy for implant placement. CONCLUSION The ridge shape significantly influenced the ease or difficulty of placing an implant. The s-shape, hourglass, and basal bone posterior mandibular cross-sectional shapes were associated with a higher degree of difficulty