Objective To investigate the clinical performance of monolithic zirconia implant crowns as compared to porcelain‐fused‐to‐metal (PFM) implant crowns. Materials and methods Seventy‐six healthy patients received reduced diameter implants in the molar region. Following random allocation, either a monolithic zirconia crown (Mono‐ZrO2) or a (PFM) was inserted. Crown and implant survival rates, modified USPHS criteria, clinical measurements, and interproximal marginal bone level (MBL) were assessed at crown delivery (baseline, BL) and at the 1‐year follow‐up (1y‐FU). Data were analyzed descriptively. Fisher's exact test and Wilcoxon rank sum test were applied for statistical analysis. The level of statistical significance was set at p < .05. Results Thirty‐nine Mono‐ZrO2 and 37 PFM crowns were delivered. At the 1y‐FU, one crown in each group was lost due to loss of the implant. Technical complications occurred in the PFM group and were limited to four minor ceramic chippings resulting in a total technical complication rate of 11.1% (p = .024). Anatomical form and color match compared to the adjacent dentition were rated significantly inferior for the Mono‐ZrO2 crowns. Patient satisfaction was high in both groups at BL (34 Mono‐ZrO2 34 PFM) and at 1y‐FU (36 Mono‐ZrO2 31 PFM). No significant differences between the groups were detected with respect to the change in MBL and to the soft tissue parameters. Conclusions Monolithic zirconia crowns are a similarly successful alternative option to PFM crowns for restoring single implants in the posterior area.

Aim:This study aimed to compare three different methods used for shade selection, i.e., visual method, spectrophotometer, and digital photography method.Materials and Methods:Fifty participants were selected from the Out Patient Department of Prosthodontics. Presence of the maxillary right central incisor with no history of any restorative or endodontic procedures was the primary inclusion criterion. The shade of the right maxillary central incisor was determined using all the three shade selection procedures, namely, visual, spectrophotometric, and digital photography method for all the selected participants. The shades obtained in the visual method using a shade guide were noted down for further comparisons. The spectrophotometer reported the L*, a*, and b* values along with the actual shade whereas the digital photography method reported only the L*, a*, and b* values. The agreement between the readings obtained by the three different methods was compared and subjected to appropriate statistical analysis.Results:The results showed that when the three methods studied were compared, there was a statistically significant proportion of agreement between spectrophotometric and visual method (P < 0.01) with higher proportion of “yes” (agreement) and between the spectrophotometric and digital photography method (P < 0.01) with higher proportion of “yes” (agreement). Coefficient of agreement (using Kappa coefficient) between spectrophotometric and visual shades revealed a fair agreement. The mean ΔE was 1.69. There was a statistically significant difference between the proportion of ΔE more than and <2, between spectrophotometric and digital photography methods (P < 0.01) with higher proportion of <2 ΔE. Furthermore, percentage of agreement between shades obtained by the visual and spectrophotometric method showed maximum agreement with A1 shade.Conclusion:It was concluded that the digital photography method emerged as a reliable method for shade selection in a clinical setup.

Implant length and macrodesign affect ISQ, MM, and IT. Clinical measurements (ISQ) and IT have limited value as an indicator of implant MM.

No abstract

This in vitro study evaluated the effect of different levels of preparation of an implant abutment on its fracture resistance. The study evaluated abutments that incorporated a platform switch (Myriad Plus Abutments, Morse Taper Connection) and Standard abutments (BioHorizons Standard Abutment, BioHorizons Inc). Each abutment was connected to an appropriate implant and mounted in a self-cured resin base. Based on the abutment preparation depths, 3 groups were created for each abutment type: as manufactured, abutment prepared 1 mm apical to the original margin, and abutment prepared 1.5 mm to the original margin. All the abutments were prepared in a standardized manner to incorporate a 0.5 mm chamfer margin uniformly. All the abutments were torqued to 30 Ncm on their respective implants. They were then subjected to loading until failure in a universal testing machine. Abutments with no preparation showed the maximum resistance to fracture for both groups. As the preparation depth increased, the fracture resistance decreased. The fracture resistance of implant abutment junction decreases as the preparation depth increases.

Aim: The purpose of this study was to compare the accuracy of conventional implant impressions with digital impression techniques made using two different intraoral scanners. Setting and Design: In-Vitro study. Material and Methods: A scan of master cast containing four implants was made using two intraoral scanners: CEREC Primescan (Dentsply Sirona, USA) and 3Shape Trios (Copenhagen, Denmark) with PEEK scan bodies attached to the implants. Model was scanned ten times using different scanners. The accuracy of the chairside scanners was compared with highly accurate laboratory scanner. The scans were transferred into the software (Geomagic Control X 20, 3D Systems, Rock Hill, SC, USA) for analysis. The linear deviations and the angular deviations between the scans (scan of each model made using high-definition scanner and the master model scan) were calculated to determine the accuracy. Trueness was used as a parameter to compare the accuracy of different scanners (comparing test and reference). Statistical Analysis: Analysis of variance was performed with Bonferroni's post hoc test for multiple group comparisons. Results: Distribution of the mean overall absolute linear deviation was significantly lower in the conventional impression group compared to the CEREC Primescan scanner group and 3Shape Trios group ( P < 0.05 for both). Distribution of the mean overall absolute linear deviation was significantly lower in the CEREC Primescan scanner group compared to the 3Shape Trios group ( P < 0.05). Distribution of the mean overall absolute angular deviation did not differ between the three groups ( P > 0.05 for all). Conclusion: Conventional impressions showed significantly greater accuracy compared to the digital impressions made with both the above intraoral scanners for implant-supported restoration of an edentulous arch. In addition, the digital impressions with the CEREC Primescan scanner showed greater accuracy as compared to the 3Shape Trios scanner.

No abstract

Background : Development in implant dentistry has led to increased demand for provisional restorative materials. However these restorative materials should possess optimum mechanical properties and color stability. Although 3D printed technology is routinely used in dentistry, However there is limited literature on the properties of 3D printed provisional restoration. This requires investigation as it is a cheaper technology than CAD-CAM and at the same time is available with a lesser start up cost. Aim/Hypothesis : To evaluate and compare color stability and flexural strength of 3D printed provisional restorations, CAD-CAM milled provisional restorations and direct chairside fabricated provisional restorations. Materials and Methods : 60 specimen each measuring 25 mm × 2 mm × 2 mm (according to ADA specification no: 27) were divided into following groups based on method of fabrication: Group 1-3D printed, Group 2-CAD/CAM milled and Group 3-Bis-acryl composite resins. 10 specimens from each group (n = 30) were immersed in a staining solution of tea and artificial saliva (1:2) and stored in an incubator at 37°C. The CIE Laboratory color coordinates were recorded before and after 7 days of immersion. The remaining specimen (n = 30) were tested for flexural strength and values obtained were evaluated. Data were statistically analyzed using one-way analysis of variance (ANOVA) with Bonferroni ' s correction for multiple group comparisons. Results : Group 1 showed significantly higher color stability as compared to Group 2 and Group 3. The mean color difference of Group 1 was found to be clinically acceptable (ΔE<3.7) after 7 days of immersion. The mean flexural strength values in Group 2 (126.14 ± 7.02 MPa) were higher compared to Group 1 (69.11 ± 3.64 MPa) and Group 3 (77.29 ± 6.73 MPa) (Figure 1). Conclusions and Clinical Implications : 3D printed specimen presented better color stability and CAD/CAM milled specimen demonstrated highest flexural strength compared to other groups. It can be concluded that clinicians should be careful while selecting 3D printed provisional restoration in posterior region.