Effect of Consecutive Removal and Placement of Abutments during Prosthetic Procedures on an Increase in Proinflammatory Cytokine Levels around Dental Implants

Objective: To evaluate the effect of repeated removal and placement of abutments during prosthetic stages on increasing proinflammatory cytokine levels around dental implants. Material and Methods: All the patients with dental implants, referring to the prosthodontics private office during a 3-month period, were examined in relation to the health of the implants and included in the present study based on inclusion criteria; the patients had a multi-unit abutment on one side of the jaw and a conventional healing abutment on the implant on the other side of the jaw. Samples of gingival crevicular fluid were taken from all the eligible subjects for immunological analyses. The samples were taken from the sulcus around each implant in each subject. The samples were sent to the immunology laboratory for determination of IL-6 and IL-1ß proinflammatory cytokines with the use of an ELISA kit. Data were analyzed with SPSS 16 and Descriptive statistics and T-test was used. Statistical significance was set at p<0.05. Results: The results showed that the mean concentrations of IL-1ß and IL-6 in the group with multi-unit abutment were less than those in the conventional abutment group. In addition, comparison of the means of IL-6 and IL-1ß concentrations showed that in both groups the concentration of IL-6 was higher than that of IL-1ß. Conclusion: The use of multi-unit abutments resulted in less inflammation compared to the use of conventional two-segment abutments, which require repeated removal and placement during the prosthetic stage.

Effect of Home Bleaching on the Color Matching of Composite Resin Restorations

Objective: To investigate the effect of home bleaching on color matching between the dental restoration and the adjacent tooth structure after the staining process. Material and Methods: Ten intact maxillary central incisors were used. After preparation (semimesial restoration of the specimens), the specimens were immersed in a colored solution for 14 days and then were washed and the bleaching process was there after performed. A spectrophotometer apparatus was used to determine the color of the specimens in the part of the tooth filled with restorative material three times, including before the staining process, fourteen days after the staining process and immediately after the bleaching process. Paired t-test was employed to compare the color of the intact tooth and the dental restoration before and after the staining and bleaching processes. The level of significance was set at 5%. Results: Pre-bleaching E color of the teeth was 68.1, which increased to 78.8% after bleaching, and this increase was also statistically significant (p<0.001). Pre and Post-bleaching E color of composite restorations was 65% and 77.6%, respectively. This increase was also statistically significant (p<0.001). Postbleaching E color of the tooth and composite material was 78.8% and 77.6%, respectively. This difference was not statistically significant (p=0.342). Conclusion: The staining and bleaching processes had a significant effect on the discoloration of the dental restoration and the tooth; however, the application of bleaching on the teeth and composite improved the tooth composite color-match.

Evaluation of Periodontal Status of Adjacent Teeth to Posterior Single- Tooth Implant during a One-Year Period after Restoration: A Cross- Sectional Study

Objective: To evaluate the periodontal status of teeth adjacent to the posterior single tooth implant during one year after restoration. Material and Methods: In this crosssectional study, 36 patients, which were systematically and had received the implant(s) of single posterior teeth over the past year were selected. The teeth adjacent to singleposterior tooth implants were evaluated regarding bleeding on probing, mobility, gingivitis and periodontal pockets during the follow up period of 3, 6 and 9 months under the supervision of two specialists. To investigate the relationship between periodontal statuses, the Chi-square test was used, and the Kruskal-Wallis test was used to assess statistical significance of periodontal indexes in the period under assessment. The p-value of less than 0.05 was considered significant. Results: There was no significant relationship between the variable of bleeding on probing, mobility, gingivitis and periodontal pocket in the studied distal and mesial teeth. Out of studied patients, after 9 months, only 11.1% had one of the periodontal problems, as a result, 88.9% of crowns replacement of single-posterior tooth does not make any periodontal damages to adjacent teeth. Conclusion: Crowns replacement of implant does not have any destructive impact on periodontal condition of adjacent teeth.