Benchmark performance of anodized vs. sandblasted implant surfaces in an acute dehiscence type defect animal model.

OBJECTIVES: Crestal bone formation represents a crucial aspect of the esthetic and biological success of dental implants. This controlled preclinical study analyzed the effect of implant surface and implant geometry on de novo crestal bone formation and osseointegration. MATERIALS AND METHODS: Histological and histomorphometrical analysis was performed to compare three implant groups, that is, (1) a novel, commercially available, gradient anodized implant, (2) a custom-made geometric replica of implant "1," displaying a superhydrophilic micro-rough large-grit sandblasted and acid-etched surface, and (3) a commercially available implant, having the same surface as "2" but a different implant geometry. The study applied a standardized buccal acute-type dehiscence model in minipigs with observation periods of 2 and 8 weeks of healing. RESULTS: The amount of newly formed crestal bone (BATA) around control groups (2) and (3) was significantly increased when compared to the test group (1) at the 8 weeks of healing time point. Similar results were obtained for all parameters related to osseointegration and direct bone apposition, to the implant surface (dBIC, VBC, and fBIC), demonstrating superior osseointegration of the moderately rough, compared to the gradient anodized functionalization. After 2 weeks, the osseointegration (nBIC) was found to be influenced by implant geometry with group (3) outperforming groups (1) and (2) on this parameter. At 8 weeks, nBIC was significantly higher for groups (2) and (3) compared to (1). CONCLUSIONS: The extent (BATA) of de novo crestal bone formation in the acute-type dehiscence defects was primarily influenced by implant surface characteristics and their ability to promote osseointegration and direct bone apposition. Osseointegration (nBIC) of the apical part was found to be influenced by a combination of surface characteristics and implant geometry. For early healing, implant geometry may have a more pronounced effect on facilitating osseointegration, relative to the specific surface characteristics.

Assessment of Antagonist Enamel Wear and Clinical Performance of Full-Contour Monolithic Zirconia Crowns: One-Year Results of a Prospective Study.

PURPOSE: To assess the clinical performance and survival of full-contour monolithic zirconia (MZ) crowns and enamel wear produced over a 1-year period. MATERIALS AND METHODS: 60 patients requiring full-coverage restorations for endodontically treated posterior teeth opposed by healthy unrestored antagonistic teeth were selected. MZ crowns were fabricated. Vinyl polysiloxane impressions of the antagonist teeth were made, and the stone casts were digitized using a 3D laser scanner. Wear of the opposing natural teeth was evaluated at baseline (1 week), 6 months, and 1 year after crown cementation. Superimposition of the follow-up scans on the baseline scans were performed to evaluate wear. Survival and function of the restorations were evaluated by the modified USPHS rating criteria at the same timeframes. RESULTS: Comparison of the baseline and the follow-up wear values was statistically tested using the paired t-test. Statistical significance was noted between the wear values at 6 months (15.5 µm) and at 12 months (16.3 µm) (p < 0.05). The Wilcoxon signed rank sum test was performed to evaluate each parameter of the modified USPHS criteria and to analyze the change in the follow-up scores of the restorations. The survival rate for the crowns was 100%. Results were classified as "excellent" over a 1-year follow up. CONCLUSIONS: MZ crowns showed promising results related to antagonist enamel wear and survival/clinical performance.

Comparison of photographic and conventional methods for tooth shade selection: A clinical evaluation.

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.

Fracture Resistance of Implant Abutments Following Abutment Alterations by Milling the Margins: An In Vitro Study.

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.