The aim of this study was to evaluate the effects of systemic fucoxanthin treatment on alveolar bone resorption in rats with periodontitis. Thirty rats were divided into control, experimental periodontitis (EP), and experimental periodontitis-fucoxanthin (EP-FUCO) groups. Periodontitis was induced by ligature for four weeks. After removal of the ligature, the rats in the EP-FUCO group were treated with a single dose of fucoxanthin (200 mg/kg bw) per day for 28 consecutive days. At the end of the study, all of the rats were euthanized and intracardiac blood and mandible tissue samples were obtained for biochemical, immunohistochemical, and histometric analyses. Fucoxanthin treatment resulted in a slight decrease in tumor necrosis factor-α, interleukin-1β, and interleukin-6 levels and a significant decrease in oxidative stress index. It was observed that fucoxanthin caused a significant reduction in receptor activator of nuclear factor kappa-β ligand (RANKL) levels and a statistically non-significant elevation in osteoprotegerin and bone-alkaline phosphatase levels. There were no significant differences in alveolar bone loss levels between the EP and EP-FUCO groups. This experimental study revealed that fucoxanthin provides a limited reduction in alveolar bone resorption in rats with periodontitis. One of the mechanisms underlying the mentioned limited effect might be related to the ability of fucoxanthin to inhibit oxidative stress-related RANKL-mediated osteoclastogenesis.

Zygomatic implants are becoming an ideal treatment approach for implant-supported prosthesis treatment developed for the atrophic maxilla. This study aims to evaluate the amount and distribution of stress in implants and peri-implant bone using different implant-supported prosthesis configurations in Aramany Class I maxillary defects through 3-dimensional finite element analysis. A 3-dimensional finite element model of the Aramany class I defect was created. Three different implant-supported prostheses were modelled: model 1: 1 zygomatic implant and 3 dental implants, model 2: 1 zygomatic implant and 2 dental implants, and model 3: 2 zygomatic implants. Vertical and horizontal loads of 150 N were applied in 6 different ways to the defected and non-defective areas. Maximum principal stress and von mises stresses in the bone surrounding the implants were evaluated. When all loading conditions were evaluated with both porcelain layer on Co-Cr framework and acrylic layer on acrylic framework, the highest maximum principal stress value was observed in Model 3. In contrast, the lowest value was observed in Model 1. The highest maximum principal stress occurred when a horizontal load was applied simultaneously to both the defective and non-defective areas. In contrast, the lowest value was observed when a vertical load was applied to the non-defective area. The von Mises stress values were found to be similar across all models when both restoration materials were used. Based on the results of this study, it can be concluded that increasing the number of implants in the non-defective area reduces the highest stress value while using acrylic as a restoration material slightly increases the stress value.

Objective: The aim of this study was to evaluate the effect of different bleaching agents on the surface roughness and color stability of feldspathic porcelain. Material and Methods: In this study, totally 40 disc-shaped Noritake and Ceramco 3 feldspathic porcelain and two bleaching agents (Opalescence Boost and Opalescence Pf) were used. Bleaching agents were exposed to specimens according to their protocol. Then, the surface roughness of the specimens was evaluated with profilometer and the color of the specimens was recorded by colorimeter. Statistical analysis of the data was performed with IBM SPSS Statistics 20. Results: The results showed that that there were statistically significant differences between the bleaching agents on the surface roughness of feldspathic porcelain (p0.05). Conclusion: The obtained data presented that the bleaching agents increased the surface roughness and not affect the color stability of the feldspathic porcelain.KeywordsBleaching; Ceramic; Color; Surface roughness.

OBJECTIVES: This study investigated the mechanical properties of laminate veneers to determine their resistance to the shear force of three different types of cement used in the restorations. MATERIAL and METHODS: Laminate veneers were prepared using the standard tooth preparation methods for 30 extracted maxillary central incisors. To standardize the depth, guide burs were used to prepare a depth of 0.5 mm from the buccal angle. The samples were allocated into three randomized groups (n = 10): Group A (resin using the total etch method and Variolink Esthetic DC resin cement; Group B (resin using the PANAVIA F2.0 self-etch method; and Group C (self-adhesion bonded with Rely X U200 resin cement). The prepared specimens were stored in distilled water for one week before a shear test was used to determine the resistance of the veneers to the bonding. The obtained data were evaluated statistically. RESULTS: The values of the shear bond strength were statistically significant depending on the type of resin cement that was applied (p ˂ 0.05). The specimens that were cemented using the total-etch method (18.79±4.48 MPa) had the lowest shear force value. The obtained data were evaluated statistically by Tukey multiple comparison test (p > 0.05). CONCLUSIONS: The cement is a highly effective factor in the bonding between fixed prosthetic restorations and the abutment tooth, and the cement used must have sufficient resistance to shear forces.