No abstract

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.

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.

Purpose To report the rate of technical complications and prosthesis survival in a cohort of edentulous patients treated with implant‐supported fixed complete dental prostheses (IFCDPs) after a mean observation period of at least 1 year. Materials and Methods The single‐visit examination included clinical and radiographic assessment, occlusal analysis, photographs and questionnaire assessing patient satisfaction in a cohort of 52 patients rehabilitated with 71 IFCDPs (supported by 457 implants). The IFCDPs were assessed for technical complications, number of implants and cantilever extension, retention type and prosthetic material type. Comparison was made between ceramic IFCDPs (Group 1) and metal‐resin IFCDPs (Group 2). Kaplan‐Meier survival curve analysis was carried out for assessment of prosthesis survival and was done for both Groups 1 and 2 separately. The Cox proportional hazard model was used for survival analysis, adjusting for a number of potential confounders, to evaluate the association between prosthesis survival and several risk factors such as type of opposing occlusion, nightguard use, and presence of bruxism. Responses to patient satisfaction questions were compared with Fisher's exact test. Results Out of 71 edentulous arches (52 patients) restored with IFCDPs, 6 IFCDPs had failed, yielding a cumulative prosthesis survival rate of 91.6 % after a mean observation period of 5.2 years (range: 1‐12 years) after definitive prosthesis insertion. Three IFCDPs were lost due to implant failures after 5.8 to 11 years of functional loading. Additionally, 3 metal‐resin IFCDPs failed due to technical complications. Minor complications were the most frequent complications observed, namely wear of the prosthetic material (9.8% annual rate) being the most common, followed by decementation of cement‐retained IFCDPs (2.9%), and loss of the screw access filing material of the screw‐retained IFCDPs (2.7%). The most frequently observed major complication was fracture of the prosthetic material (1.9% annual rate), followed by fracture of occlusal screw (0.3%), and fracture of framework (0.3%). The annual rate of wear of prosthetic material was 7.3% for porcelain IFCDPs (n = 19/55) and 19.4% for metal‐resin IFCDPs (n = 13/16), yielding a statistically significant difference between the 2 groups (p = 0.01). Conclusions After a mean exposure time of 5.2 years, 91.6% prosthesis survival rates were achieved (65 out of 71 IFCDPs). The most frequent minor technical complication was wear of the prosthetic material with estimated 5‐year rate of 49.0%, while the most frequent major complication was fracture of the prosthetic material with estimated 5‐year dental unit‐based rate of 9.5%. The cumulative rates for “prosthesis free of minor complications” at 5‐ and 10‐years were 60.5% (95% CI: 47.2‐71.3%) and 8.9% (95% CI: 2.9‐18.0%), respectively. The cumulative rates for “prosthesis free of major technical complications” at 5‐ and 10‐years were 85.5% (95% CI: 73.0‐92.5%) and 30.1% (95% CI: 12.0‐50.6%), respectively. Pr...

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.

Purpose:To report the rate of technical complications and prosthesis survival in a cohort of edentulous patients treated with implant-supported fixed complete dental prostheses (IFCDPs) after a mean observation period of at least 1 year. Materials and Methods: The single-visit examination included clinical and radiographic assessment, occlusal analysis, photographs and questionnaire assessing patient satisfaction in a cohort of 52 patients rehabilitated with 71 IFCDPs (supported by 457 implants). The IFCDPs were assessed for technical complications, number of implants and cantilever extension, retention type and prosthetic material type. Comparison was made between ceramic IFCDPs (Group 1) and metal-resin IFCDPs (Group 2). Kaplan-Meier survival curve analysis was carried out for assessment of prosthesis survival and was done for both Groups 1 and 2 separately. The Cox proportional hazard model was used for survival analysis, adjusting for a number of potential confounders, to evaluate the association between prosthesis survival and several risk factors such as type of opposing occlusion, nightguard use, and presence of bruxism. Responses to patient satisfaction questions were compared with Fisher's exact test. Results: Out of 71 edentulous arches (52 patients) restored with IFCDPs, 6 IFCDPs had failed, yielding a cumulative prosthesis survival rate of 91.6 % after a mean observation period of 5.2 years (range: 1-12 years) after definitive prosthesis insertion. Three IFCDPs were lost due to implant failures after 5.8 to 11 years of functional loading. Additionally, 3 metal-resin IFCDPs failed due to technical complications. Minor complications were the most frequent complications observed, namely wear of the prosthetic material (9.8% annual rate) being the most common, followed by decementation of cement-retained IFCDPs (2.9%), and loss of the screw access filing material of the screw-retained IFCDPs (2.7%). The most frequently observed major complication was fracture of the prosthetic material (1.9% annual rate), followed by fracture of occlusal screw (0.3%), and fracture of framework (0.3%). The annual rate of wear of prosthetic material was 7.3% for porcelain IFCDPs (n = 19/55) and 19.4% for metal-resin IFCDPs (n = 13/16), yielding a statistically significant difference between the 2 groups (p = 0.01). Conclusions: After a mean exposure time of 5.2 years, 91.6% prosthesis survival rates were achieved (65 out of 71 IFCDPs). The most frequent minor technical complication was wear of the prosthetic material with estimated 5-year rate of 49.0%, while the most frequent major complication was fracture of the prosthetic material with estimated 5-year dental unit-based rate of 9.5%. The cumulative rates for "prosthesis free of minor complications" at 5-and 10-years were 60.5% (95% CI: 47.2-71.3%) and 8.9% (95% CI: 2.9-18.0%), respectively. The cumulative rates for "prosthesis free of major technical complications" at 5-and 10-years were 85.5% (95% CI: 73.0-92.5%) and

The aim of this clinical report is to describe a complete digital workflow protocol for mandibular full‐arch implant rehabilitation from guided surgery to definitive prosthesis in only 3 appointments. This expedited protocol allows for guided implant placement with a system of stackable surgical templates and CAD/CAM prosthodontic rehabilitation using a digital workflow. At the first appointment, a guided implant placement protocol with the stackable template concept was done followed by immediate loading with a prefabricated interim prosthesis. At the same appointment, the Double Digital Scanning (DDS) technique was used for scanning, maxillomandibular relationship registration and virtual articulation. The anchor pins from guided surgery were used as fiducial markers for DDS data superimposition. At the second appointment, the prosthesis prototype was tried‐in and adjustments were made. At the third appointment, the definitive monolithic zirconia full‐arch prosthesis was delivered.

Purpose: The aim of this systematic review was to determine which dowel (post) and core system is the most successful when used in vivo to restore endodontically treated teeth. Materials and Methods: A MEDLINE, a Cochrane, and an EMBASE search (three specified searches) were conducted to identify randomized (RCT) and nonrandomized controlled clinical trials (CCT), cohort (CS), and case control studies (CCS) until January 2008, conducted on humans, and published in English, German, and French, relating to dowel and core systems for restoring endodontically treated teeth. Also, a hand search was conducted, along with contact with the authors when needed. Results: The MEDLINE, Cochrane, and EMBASE searches identified 997, 141, and 25 published articles, respectively. Ten articles from the MEDLINE and seven articles from the Cochrane search (that were also identified in the MEDLINE search) met the inclusion and validity assessment criteria. Six out of the ten studies were RCTs, two were CCTs, and two CSs. The RCT studies suggest that carbon fiber in resin matrix dowels are significantly better than precious alloy cast dowels (number needed to treat, NNT = 8.30). Tapered gold alloy cast dowels are better than ParaPost R gold alloy cast dowels (NNT = 13.15). ParaPost R prefabricated dowels are slightly better than ParaPost R cast dowels (NNT = 175.4). Glass fiber dowels are significantly better than metal screw dowels (NNT = 5.46), but worse than titanium (NNT = −21.73) (moderately). Carbon fiber dowels are worse than gold alloy cast dowels (significantly) (NNT = −5.81) and than amalgam dowels (NNT = −125) (slightly). The CCT studies suggest that metal dowels are better (NNT = 21.73) but also worse than cast dowels (NNT = −33.33) depending on the remaining amount of coronal hard tissue. Quartz fiber dowels show success rates similar to and worse than glass fiber-reinforced dowels (NNT = −37.03). The results from the CS studies suggest that carbon fiber in resin matrix dowels are better (moderately) than carbon fiber + quartz and quartz fiber dowels. Titanium dowels with a composite build-up are better (moderately) than gold alloy cast dowels. Conclusions: According to the studies of the highest levels of evidence, carbon fiber in resin matrix dowels are significantly better than precious alloy cast dowels (RCT). Glass fiber dowels are significantly better than metal screw dowels (RCT) and moderately better than quartz fiber dowels (CCT). Carbon fiber dowels are significantly worse than metal dowels (of precious alloy) (RCT). Prefabricated metal dowels are slightly better than cast dowels (RCT), but moderately worse when no collar of the dentin above the gingiva could be achieved (CCT).The purpose of this study was to compare different dowel and core materials based on the available clinical trials of the highest level of evidence. The analysis was limited to levels 1 to 3 of clinical evidence, because these levels are able to demonstrate causality. Controlled clinical trials, randomized or not (level 1), cohor...