Introduction of a prediction model to assigning periodontal prognosis based on survival time.

AIMS: To develop a prediction model for tooth loss due to periodontal disease (TLPD) in patients following periodontal maintenance (PM), and assess its performance using a multicentre approach. MATERIAL AND METHODS: A multilevel analysis of eleven predictors of TLPD in 500 patients following PM was carried out to calculate the probability of TLPD. This algorithm was applied to three different TLPD samples (369 teeth) gathered retrospectively by nine periodontist, associating several intervals of probability with the corresponding survival time, based on significant differences in the mean survival time. The reproducibility of these associations was assessed in each sample (One-way ANOVA and pairwise comparison with Bonferroni corrections). RESULTS: The model presented high specificity and moderate sensitivity, with optimal calibration and discrimination measurements. Seven intervals of probability were associated with seven survival time and these associations contained close to 80% of the cases: the probability predicted the survival time at this percentage. The model performed well in the three samples, as the mean survival time of each association were significantly different within each sample, while no significant differences between the samples were found in pairwise comparisons of means. CONCLUSIONS: This model might be useful for predicting survival time in different TLPD samples.

Five-year outcomes of a randomized clinical trial comparing bone-level implants with either submerged or transmucosal healing.

AIM: To evaluate the long-term hard and soft tissue peri-implant tissue stability of bone-level implants using a different implant placement protocol (submerged versus transmucosal). MATERIALS AND METHODS: This study was partly a subset analysis of a multicentre study where in 40 patients, a single bone-level implant with platform switching and a conical implant-abutment interface was placed either submerged or transmucosal in non-molar sites. Changes in the peri-implant tissues between implant placement and 5 years were assessed clinically and radiologically. Patient-related outcomes were also recorded. RESULTS: Thirty patients completed the 5-year follow-up. Implant survival rate was 100%. The mean radiographic changes in crestal bone levels between baseline and 5 years were 0.59 (0.92) mm and 0.78 (1.03) mm for the submerged and the transmucosal groups, respectively. No statistical significant differences were found between the groups for any of the investigated variables. Peri-implantitis, defined as changes in the level of crestal bone of ≥2 mm together with bleeding on probing, was only diagnosed in one patient. Patients in both groups were highly satisfied with the treatment received. CONCLUSIONS: Bone-level implants with submerged or transmucosal healing protocols demonstrated similar outcomes after 5 years. Both protocols yielded optimal clinical and radiographic results when bone-level implants were placed in non-molar positions for single tooth replacement.