Richardsonmarker5571

To evaluate the wear of zirconia on natural teeth in humans in vitro and in vivo.

Embase, the Cochrane Database, PubMed, and the Web of Science were searched (January 2014 to May 2019), and all references were retrieved. After preliminary screening of the literature, two researchers read the full texts of the remaining literature and determined whether the literature should be included. Data and information were extracted from the included literature, then analyzed and discussed.

A total of 49 in vivo experiments and 229 in vitro experiments were retrieved. After duplication removal and screening, 7 in vivo studies and 13 in vitro studies were included. The results of the in vitro studies showed that fine polished zirconia causes less antagonist wear on natural teeth than other treatments with zirconia or other restorative materials. The results of the in vivo studies showed the antagonist wear of zirconia on natural teeth was within the clinically acceptable range.

Both in vivo and in vitro studies have shown polishing can reduce the wear of zirconia on natural teeth more than glazed or veneering porcelain. However, whether glazed zirconia causes less natural tooth wear after polishing is still a matter of debate. Due to the short observation period and heterogeneity of the experiment, the above conclusions should be carefully interpreted.

Both in vivo and in vitro studies have shown polishing can reduce the wear of zirconia on natural teeth more than glazed or veneering porcelain. Repotrectinib However, whether glazed zirconia causes less natural tooth wear after polishing is still a matter of debate. Due to the short observation period and heterogeneity of the experiment, the above conclusions should be carefully interpreted.

To evaluate the trueness of digital impressions of different composite resin materials that can be used for core build-ups in clinical practice.

A maxillary central incisor was prepared and scanned with an intraoral scanner (Primescan, Dentsply Sirona). Ten composite resin specimens (in three groups universal composite; flowable composite; and bulk fill resin composite) were milled in the same dimensions of the prepared tooth and scanned. The data of the prepared tooth were used as reference, and the data obtained from the composite resin specimens were aligned with the evaluation software (Geomagic Studio 12) to determine deviation values. Kruskal-Wallis with Dunn post hoc test was performed (α = .05).

There were significant differences in the trueness of digital impressions between some composite resin groups (P < .05). The mean trueness deviation values were in the range of 12.75 μ m (G-aenial Posterior) to 17.06 μ m (Filtek Bulk Fill Posterior). The trueness of G-aenial Posterior (12.75 μ m) was higher than that of Core-X Flow (14.62 μ m), Clearfil Majesty Flow (16.93 μ m), and Filtek Bulk Fill Posterior (17.06 μ m). Filtek Bulk Fill Posterior exhibited lower trueness than Clearfil Majesty Esthetic (12.93 μ m), Clearfil Majesty Posterior (13.50 μ m), and Charisma Classic (13.81 μ m).

Different composite resins used for core build-up can impact the trueness of digital impressions, with universal composite resin scans being the truest compared to flowable and bulk fill composite resin scans. All scanned substrate groups can be regarded as within a clinically acceptable range.

Different composite resins used for core build-up can impact the trueness of digital impressions, with universal composite resin scans being the truest compared to flowable and bulk fill composite resin scans. All scanned substrate groups can be regarded as within a clinically acceptable range.

To compare the precision of adaptation of cobalt-chromium (Co-Cr) three-unit fixed dental prostheses (FDPs) fabricated using different techniques.

A master model was prepared to receive a three-unit FDP. This model was duplicated 60 times from a silicone mold. The dies (N = 60) were scanned and divided into three groups (n = 20 each) to receive the FDPs made of pre-sintered Co-Cr (CS), laser-sintered Co-Cr (LS), or cast Co-Cr (Gi). Frameworks were layered with ceramic, and each framework was seated on its specific model. The replica technique was used to measure the marginal and internal discrepancies in the mesiodistal and buccolingual planes. Prepared silicone samples were examined with scanning electron microscopy. Obtained data were analyzed using Levene test, t test, and analysis of variance (α = .05).

When overall mean discrepancy values were compared, in mesiodistal planes, LS showed better adaptation than Gi (P = .025). Similar adaptation was found for CS and Gi, and for CS and LS (P = .169 and P = 1.000, respectively). In buccolingual planes, the difference in fit was not significant among the three tested groups (P > .05). In a pairwise comparison between materials, a net increase in values between points 1 and 5 was noted (P = .57). Difference in discrepancy values within points was significant. This was confirmed at abutment level on some measurement points. Within each material, at abutment level, differences were significant at several measurement locations in both the mesiodistal and buccolingual planes.

Within the limitations of this study, three-unit Co-Cr FDPs showed similar marginal and internal discrepancy values. Presintered and laser-sintered Co-Cr alloys can be considered for three-unit FDP fabrication.

Within the limitations of this study, three-unit Co-Cr FDPs showed similar marginal and internal discrepancy values. Presintered and laser-sintered Co-Cr alloys can be considered for three-unit FDP fabrication.

To determine and compare the mechanical properties of 3D-printed yttriastabilized zirconia to milled isostatic pressed yttria-stabilized zirconia, with the following hypotheses (1) The flexural strength of 3D-printed yttria-stabilized zirconia is comparable to milled yttria-stabilized isostatic pressed zirconia; and (2) thermocycling and chewing simulation do not affect the flexural strength of 3D-printed yttria-stabilized zirconia.

A total of 30 bars of an experimental 3D-printed 3 mol% yttriastabilized zirconia (LithaCon 3Y 230, Lithoz) and 10 bars of milled isostatic pressed zirconia (Prettau Zirconia, Zirkonzahn) were utilized. The printed zirconia bars were divided into three groups (n = 10 bars per group) (1) untreated (control); (2) thermocycled; and (3) tested after chewing simulation. A flexural strength test was performed on all samples using a three-point bend test in an Instron Universal testing machine. One-way analysis of variance on ranks was used to compare milled to printed zirconia. The effects of thermocycling and load cycling on 3D-printed zirconia were also determined.