The Impact of Repeated Steam Sterilization Cycles on the Efficacy of Chairside Adjustment Kits for Polishing Monolithic Multi-Layered Zirconia Dental Restoration Material.

BACKGROUND Before insertion, chairside adjustment kits are heat sterilized for positioning and polishing dental restorations. This study aimed to evaluate the effects of 2 steam sterilization cycles on the efficacy of polishing highly translucent monolithic zirconia (HTMLZ) dental restoration material. MATERIAL AND METHODS 100 HTMLZ disc-shaped specimens were adjusted (grinding, finishing, polishing) with EVE Diacera kit. Two steam sterilization techniques [standard (Gp S), immediate/flash (Gp (F)] of CAK were further subgrouped based on number of sterilization cycles [cycle 1 (control), cycle 5, 10, 15, and 20 (experimental)] (n=10 each). Each subgroup accordingly was evaluated for average surface roughness (Ra) and root mean square roughness (Rq) using a profilometer. Mean and standard deviation of 5 subgroups were statistically analyzed using one-way ANOVA/post hoc Tukey's test. Scanning electron microscopy complemented Ra, Rq measurements. Statistical differences of P≤0.05 were considered significant. RESULTS HTMLZ specimens in both groups showed increased (Ra/Rq) values after repeated sterilization of EVE Diacera kit, with Gp F showing lesser increase than Gp S (20 cycles). Gp F at 10 cycles and Gp S at 15 cycles showed clinically unacceptable roughness threshold (0.25 µm). Differences between subgroups for Ra and Rq values were significant (P≤0.05) with less differences within groups observed in early cycles (1, 10). Results validate the manufacturer's recommendations of using flash sterilization/10 cycles for EVE Diacera kit. CONCLUSIONS Repeated sterilization reduces efficacy of chairside adjustment kit to produce smooth surfaces on HTMLZ. This study recommends flash sterilization to a maximum of 10 times to get the clinically acceptable results of Ra and Rq.

Intraoral Scan Accuracy and Time Efficiency in Implant-Supported Fixed Partial Dentures: A Systematic Review.

The digital implant impression technique (DIT) and conventional implant impression technique (CIT) workflows in implant-supported fixed partial dentures (FPDs) have not been extensively compared in prior studies. Moreover, there is no agreement on the more accurate method that entails less time in the laboratory and during the clinical phases of fabrication and delivery of the prosthesis, respectively. This review aimed to assess the precision of the imaging procedure and overall fabrication time of the DIT and CIT for the implant-supported FPDs. An electronic search was performed using PubMed, Scopus, EMBASE, Cochrane Oral Health Group, and Dentistry and Oral Science Source databases through EBSCO for relevant studies from January 2014 to April 2023. Following the preliminary screening, the studies that met the inclusion criteria underwent full-text review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Cochrane Collaboration risk of bias appraisal tool and Newcastle-Ottawa scale were applied to assess the quality of randomized controlled trials (RCTs) and non-randomized prospective clinical studies, respectively. The initial search yielded 332 studies, and after excluding duplicates, 241 papers were available for screening. Titles and abstracts were reviewed, and 97 articles were chosen for full-text review by two authors independently. Furthermore, 89 articles were excluded in compliance with the PICOS question, and eight studies were chosen for qualitative analysis. Hence, the review comprised two RCTs and six prospective clinical studies. The time efficiency of the implant-supported FPDs was examined in four investigations, three of which used the Trios 3 scanner and one used the Intero scanner. The three-dimensional accuracy of DIT and CIT was compared in six clinical comparative studies. One of the RCTs was rated to have a high risk of bias and the other with a moderate quality of evidence. The six prospective studies were rated to have high-quality of evidence. The findings of this review indicate the prospective applicability of future intraoral scanning systems. The DIT was reported to be outstanding in terms of patient preferences and total fabrication time efficiency. Additional in vivo studies are needed to establish the therapeutic usefulness and time efficiency of integrating DIT in more comprehensive settings.