Objectives: This study aimed to assess the effect of three commonly consumed beverages on surface roughness of polished and glazed zirconia-reinforced lithium silicate (ZLS) glass ceramics. Materials and Methods: In this experimental study, 104 rectangular specimens were cut from Vita Suprinity blocks with 2 mm thickness. After ultrasonic cleaning and firing of the specimens, they were finished and polished in two groups. Specimens in the first group were polished using a 2-step polishing kit while the second group specimens were glazed and heated in a porcelain firing oven according to the manufacturer’s instructions. Baseline surface roughness was measured using a profilometer. Specimens in each group were then randomly divided into 4 subgroups (n=13) for immersion in artificial saliva (control group), cola, orange juice and black tea. Surface roughness was measured again and data were analyzed using two-way ANOVA. Results: The highest and the lowest mean Ra were found in orange juice and saliva subgroups, respectively in both glazed and polished groups. The Ra values of both polished and glazed groups significantly increased after immersion in orange juice and cola (P<0.05). The polished surfaces showed insignificantly higher surface roughness compared with glazed surfaces (P>0.05). Conclusion: Orange juice and cola significantly increased the surface roughness of both polished and glazed ZLS ceramics. Type of surface finishing (polishing versus glazing) had no significant effect on the surface roughness of specimens following immersion in different beverages.

Objectives: This study aimed to compare the marginal fit of temporary restorations fabricated by the conventional chairside method, 3D printing, and milling. Materials and Methods: In this in vitro, experimental study, 14 temporary restorations were conventionally fabricated over an implant abutment and analog that had been mounted in a phantom model at the site of canine tooth, using auto-polymerizing acrylic resin and putty index. In digital manufacturing, the original model was scanned, and the final restoration was designed. Fourteen temporary restorations were milled out of polymethyl methacrylate (PMMA) blocks, and 14 others were printed by a 3D printer. Temporary crowns were placed on the abutment, and images were obtained from specific areas under a stereomicroscope at x100 magnification to measure the amount of marginal gap. Data were analyzed using one-way ANOVA and Tukey’s test (α=0.05). Results: The mean marginal gap values for the temporary crowns in the 3D printing, milling, and chairside groups were 91.40, 75.28 and 51.23 µm, respectively. The crowns that were conventionally fabricated chairside exhibited the lowest marginal gap, and the difference in this respect was significant among the three groups (P<0.05). Conclusion: Temporary crowns fabricated by the chairside method showed significantly smaller marginal gap; however, the marginal gap of all three groups was within the clinically acceptable range.

Background. Dental implantation has become widespread for esthetic and functional rehabilitation following single tooth loss as a preferred alternative to conventional tooth-supported restorations. The main advantage of dental implant placement is that it does not require the preparation of the adjacent sound teeth. Objectives. The aim of this cohort study was to assess the effect of dental implantation on the hard and soft tissues around the adjacent natural teeth. Material and methods. In this historical cohort, 34 ' connect-type' TBR ® implants (bone level), 4 mm in diameter, were submerged in the intact bone of 22 patients (7 males and 15 females). The intraoral and extraoral clinical examination as well as periapical radiography were carried out preoperatively or right after surgery (baseline), at 3 months postoperatively (the time of prosthetic delivery), and at 3 and 6 months after prosthetic delivery. The data was analyzed using the Friedman test (due to the non-normal distribution of the data). In case of presence of a significant difference, pairwise comparisons were performed using the post-hoc Wilcoxon test with the Bonferroni correction. All statistical analyses were performed with a 95% confidence interval (CI) using the SPSS for Windows, v. 16.0 software. The p-value <0.05 was considered statistically significant. Results. The distance from the cementoenamel junction (CEJ) of the adjacent teeth to the bone crest significantly increased at different postoperative time points compared to baseline (p < 0.001). The changes in the papillae of the adjacent teeth were also significant at different postoperative time points (p = 0.04). The pocket depth of the adjacent teeth increased, although the value at 3 months postoperatively was not significantly different from the baseline value (p = 0.842). The distance from the implant shoulder to the bone crest of the adjacent teeth significantly increased at different postoperative time points compared to baseline (p < 0.001). Conclusions. Our results indicate that implant surgery significantly affects the soft and hard tissues around the adjacent natural teeth.

Objective. Our aim in this paper was to investigate the possible genetic association between three Ser563Asn, Leu125Val and Arg670Gly polymorphisms of the PECAM-1 gene and periodontitis. Methods. Genomic DNA was isolated from whole blood of 105 periodontal patient (52 with chronic periodontitis and 53 with aggressive periodontitis) and 101 healthy individuals. Samples were genotyped and analyzed for the three single-nucleotide polymorphisms (SNPs) of PECAM-1 using polymerase chain reaction with sequence-specific primers (PCR-SSPs). Results. A statistically significant difference was found between the genotypic distribution of the Ser563Asn polymorphism in patients with periodontitis compared to controls (P = 0.02). But there were no statistically significant difference between the allele frequencies in the different groups (P = 0.05). The other two polymorphisms did not show a statistically significant difference in their allele and genotype frequencies between the groups. There was no statistically significant difference found for any of the polymorphisms allele and genotype distribution in aggressive and chronic periodontitis either. Conclusions. No significant association was found between the polymorphism tested and the subgroups of periodontitis, further research is still necessary to determine whether this polymorphism can be used as a genetic marker of periodontitis.

Background:Numerous factors have an effect on the accuracy of an impression and resultant cast, and these include: impression material, impression technique, tray selection, impression disinfection, storage time of impression before pouring, stone type used for fabrication of cast. Up to now, there has been little research conducted on the effect of contact time of a cast with an impression, on the dimensional stability of a cast. Objectives: The purpose of this study was to evaluate the effect of the contact time of silicone impression materials with stone casts, on the dimensional stability of resultant casts. Materials and Methods: A total of 44 impressions were made from a stainless steel master model, with each one of two silicone impression materials (Elite HD+ and Speedex), and poured with Elite Master Type IV. The thickness of the light-body material (1 mm) was provided by using four copings. The resulting casts from each material were placed in four groups (n = 11) after each contact time with the impression (1 hour, 24 hours, 48 hours, 1 week). Distance between anterior and posterior abutments was measured for the casts and master model. Data were analyzed by two-way analysis of variance and a Tukey test. Results:The relationship between the dimensional stability of the casts and the simultaneous effect of the impression material and contact time of the cast with the impression was not statistically significant (P = 0.099). Type of impression material on the dimensional stability of the cast had no significant effect (P = 0.163). Increased contact time of the cast with the impression resulted in increased dimensional change (P < 0.001). Conclusions: Dimensional stability of the casts after different contact time with the impression was acceptable. The best time to separate the cast from the impression was one hour after pouring the impression.