Effect of dental implantation on the hard and soft tissues around the adjacent natural teeth.

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 p­value <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.

Comparison of the effect of three autogenous bone harvesting methods on cell viability in rabbits.

Background. This study was designed to compare the viability of autogenous bone grafts, harvested using different methods, in order to determine the best harvesting technique with respect to more viable cells. Methods. In this animal experimental study, three harvesting methods, including manual instrument (chisel), rotary device and piezosurgery, were used for harvesting bone grafts from the lateral body of the mandible on the left and right sides of 10 rabbits. In each group, 20 bone samples were collected and their viability was assessed using MTS kit. Statistical analyses, including ANOVA and post hoc Tukey tests, were used for evaluating significant differences between the groups. Results. One-way ANOVA showed significant differences between all the groups (P=0.000). Data analysis using post hoc Tukey tests indicated that manual instrument and piezosurgery had no significant differences with regard to cell viability (P=0.749) and the cell viability in both groups was higher than that with the use of a rotary instrument (P=0.000). Conclusion. Autogenous bone grafts harvested with a manual instrument and piezosurgery had more viable cells in comparison to the bone chips harvested with a rotary device.

A Comparative Study of Clinical Parameters in Submerged and Non submerged Implants.

AIM: The aim of this study was to evaluate and compare the radiographic bone loss and soft tissue parameters around one stage and two stage implants. MATERIALS AND METHODS: Twenty four patients with submerged implants and twenty four patients with non submerged implants at the time of loading were assessed in this prospective cohort study. The soft tissue assessment included probing depth (PD), papilla index (PI), mucosal thickness (MT) and keratinized tissue (KG); another parameter assessed was the radiographic distance between the shoulder of the implant and alveolar crest evaluated at baseline (loading time) and 3,6 and 12 months after loading in both groups.Data were analysed using repeated measures analysis of variance (ANOVA) and multiple comparisons were done using LSD method. RESULTS: The changes in the soft tissues including PD, KG, MT and PI had no significant differences in either group. The amount of bone loss 3 and 6 months after loading was significantly greater in one stage implants (0.93±0.45 mm at 3months and1.45±0.58 mm at 6months, for one stage and 0.32±0.21 mm at 3months and 0.74±0.43 mm at 6 months for two stage group). But the change of this index 12 months later was not significantly different between the two groups (1.87±0.76mm for one stage and 1.65±0.59mm for two stage group). CONCLUSION: Based on the results of this study there is no difference in hard and soft tissue changes one year after loading of one or two stage implants.

The Efficacy of Brushing and Flossing Sequence on Control of Plaque and Gingival Inflammation.

PURPOSE: To evaluate the efficacy of brushing and flossing order on control of plaque and gingival inflammation. MATERIALS AND METHODS: This cross-over clinical trial was conducted on 35 students recruited from the dental school at Hamadan University of Medical Sciences. The subjects were asked to use dental floss and then brush for a 2-week period (FB), followed by brushing and then using dental floss for another 2-week period (BF). For a 7-day washout interval between the two phases, the subjects practiced dental hygiene according to their habitual method. The participants received dental prophylaxis at the beginning and plaque control record (PCR), plaque index (PI) and bleeding point index (BPI) were measured at baseline and the end of both phases. The differences of indices between two phases were analysed with the Wilcoxon signed rank test; to assess the influence of sex and sequence on PCR, PI and BPI, analysis of covariance (ANCOVA) was used after adjustment of initial values. RESULTS: The PCR and PI indices in the FB method were significantly lower than with the BF method (P < 0.05). The PI and PCR index differences between the two phases were significant in men but nonsignificant in women. The effect of gender on PI and BPI and the interaction effect of sex and sequence of brushing and flossing on BPI were significant (P < 0.05). CONCLUSIONS: Flossing followed by brushing provides more statistically significant improvements over brushing followed by flossing with respect to plaque control.