Interproximal implant thread exposure after initial bone remodeling as a risk indicator for peri-implantitis.

BACKGROUND: Due to the clinical challenges involved in successfully treating peri-implantitis, it is imperative to identify patient- and implant-level risk factors for its prevention. The main goal of this retrospective longitudinal radiographic and clinical study was to investigate whether interproximal radiographic implant thread exposure after physiological bone remodeling may be a risk factor for peri-implantitis. The secondary goal was to evaluate several other potential risk indicators. METHODS: Of 4325 active dental school patients having implants placed, 165 partially edentulous adults (77 men, 88 women) aged 30-91 with ≥2 years of follow-up upon implant restoration were included. Implants with ≥1 interproximal thread exposed (no bone-to-implant contact) (n = 98, 35%) constituted the test group and those without exposed threads (n = 182, 65%) the control group. Descriptive, binary, and multivariate regression analyses were evaluated for goodness of fit. Wald tests were used to evaluate for significance set at 0.05. RESULTS: Of the 280 implants (98 test, 182 control), 8 (2.9%) failed over a mean follow-up period of 7.67 (±2.63) years, and 27 implants (19 test, 8 control) developed peri-implantitis, with the exposed group having eight-fold (7.82 times) adjusted greater odds than the non-exposed. The risk increased four-fold (3.77 times) with each thread exposed. No other patient- or implant-related potentially confounding risk factors were identified. CONCLUSIONS: Exposed interproximal implant threads after physiologic bone remodeling may be an independent risk indicator for incident peri-implantitis. Hence, clinicians should closely monitor patients with implant threads that have no bone-to-implant contact for incident peri-implantitis.

Long term comparison of the prognostic performance of PerioRisk, periodontal risk assessment, periodontal risk calculator, and staging and grading systems.

BACKGROUND: Clinicians predominantly use personal judgment for risk assessment. Periodontal risk assessment tools (PRATs) provide an effective and logical system to stratify patients based on their individual treatment needs. This retrospective longitudinal study aimed to validate the association of different risk categories of four PRATs (Staging and grading; Periodontal Risk Assessment (PRA); Periodontal Risk Calculator; and PerioRisk) with periodontal related tooth loss (TLP), and to compare their prognostic performance. METHODS: Data on medical history, smoking status, and clinical periodontal parameters were retrieved from patients who received surgical and non-surgical periodontal treatment. A comparison of the rate of TLP and non-periodontal related tooth loss (TLO) within the risk tool classes were performed by means of Kruskal-Wallis test followed by post-hoc comparison with the Bonferroni test. Both univariate and multivariate Cox Proportional hazard regression models were built to analyze the prognostic significance for each single risk assessment tool class on TLP. RESULTS: A total of 167 patients with 4321 teeth followed up for a mean period of 26 years were assigned to four PRATs. PerioRisk class 5 had a hazard ratio of 18.43, Stage 4 had a hazard ratio of 7.99, and PRA class 3 had a hazard ratio of 6.13 compared with class/stage I. With respect to prognostic performance, PerioRisk tool demonstrated the best discrimination and model fit followed by PRA. CONCLUSION: All PRATs displayed very good predictive capability of TLP. PerioRisk showed the best discrimination and model fit, followed by PRA.

External validation and comparison of the predictive performance of 10 different tooth-level prognostic systems.

AIM: Tooth-level prognostic systems can be used for treatment planning and risk assessment. This retrospective longitudinal study aimed to evaluate the prognostic performance of 10 different tooth-level risk assessment systems in terms of their ability to predict periodontal-related tooth loss (TLP). MATERIALS AND METHODS: Data were retrieved retrospectively from patients who received surgical and non-surgical periodontal treatment. Data on medical history and smoking status at baseline and the last maintenance visit were collected. Ten tooth-level prognostic systems were compared using both univariate and multivariate Cox proportional hazard regression models to analyse the prognostic capability of each system for predicting TLP risk. RESULTS: One-hundred and forty-eight patients with 3787 teeth, followed-up for a mean period of 26.5 ± 7.4 years, were evaluated according to 10 different tooth-level prognostic systems, making up a total of 37,870 individual measurements. All compared prognostic systems were able to stratify the risk of TLP at baseline when different classes of association were compared. After controlling for maintenance, age, and gender, all systems exhibited excellent predictive capacity for TLP with no system scoring a Harrell's C-index less than 0.925. CONCLUSIONS: All tooth-level prognostic systems displayed excellent predictive capability for TLP. Overall, the Miller and McEntire system may have shown the best discrimination and model fit, followed by the Nunn et al. system.

Maintenance visit regularity has a different impact on periodontitis-related tooth loss depending on patient staging and grading.

AIM: To assess whether maintenance variables have a differential effect on tooth loss due to periodontitis (TLP) based on staging and grading. MATERIALS AND METHODS: Patients treated for periodontitis for a minimum of ≥10 years follow-up were included and categorized according to their stage and grade at baseline. Impact of number, regularity, and pattern of supportive periodontal therapy visits (SPT) on TLP was explored by dividing teeth into test (5 year time periods prior to TLP events) and control groups (random 5 year periods without tooth loss). RESULTS: The regularity of maintenance visits, but not the overall quantity, had a significant impact on risk of TLP and showed higher importance as staging and grading increased (larger impact for stages III/IV and grade C). The minimum threshold of visits below which the risk of TLP was equivalent to that of the control group was one visit every 7.4 months for stages I-II, 6.7 months for stage III-IV, 7.2 months for grade B and 6.7 months for grade C. This frequency should be increased for former and current smokers, diabetics and elderly patients. Stage III and IV patients who skip more than 1 year of maintenance in a 5 year period have an increased risk of TLP (OR = 2.55) compared to those only miss 1 year. A similar trend was noted for grade C patients, but not for stages I/II or grades A/B. CONCLUSIONS: Lack of SPT regularity and missing multiple years of maintenance had a larger influence on risk of TLP for higher-level staging and grading.

The correlation between history of periodontitis according to staging and grading and the prevalence/severity of peri-implantitis in patients enrolled in maintenance therapy.

BACKGROUND: The aim of this study was to determine if a previous history of periodontitis according to the preset definitions of the 2017 World Workshop is correlated with increased implant failure, and occurrence and severity of peri-implantitis (PI). METHODS: A retrospective analysis of patients with a history of periodontitis who received nonsurgical and, if indicated, surgical corrective therapy prior to implant placement was performed. Periodontitis stage and grade were determined for each included patient based on data from the time of initiation of active periodontal therapy. Cox Proportional Hazard Frailty models were built to analyze the correlation between stage and grade of periodontitis at baseline with implant failure, as well as occurrence and severity of PI. RESULTS: Ninety-nine patients with a history of periodontitis receiving 221 implants were followed for a mean duration of 10.6 ± 4.5 years after implant placement. Six implants (2.7%) failed and a higher rate of implant failure due to PI was found for Grade C patients (P < 0.05), whereas only an increased trend was seen for Stages III and IV compared with I and II. Grading significantly influenced the risk of marginal bone loss (MBL) >25% of the implant length (P = 0.022) in PI-affected implants. However, a direct correlation between higher-level stage and grade and PI prevalence was not recorded. CONCLUSION: No statistically significant association between periodontitis stage or grade and the prevalence of PI was found. However, when PI was diagnosed, there was a relationship between periodontitis grade and severity of PI or the occurrence of implant failure.

The influence of the interaction between staging, grading and extent on tooth loss due to periodontitis.

AIM: To assess the ability of two-way interactions between baseline stage, grade and extent to predict tooth loss due to periodontitis (TLP) over a long-term follow-up period. MATERIALS AND METHODS: Patients treated for periodontal disease with a complete medical history, baseline periodontal chart, full mouth radiographs and a minimum of ≥10 years follow-up were recruited. Supportive periodontal therapy (SPT) visits were recorded during the entire follow-up period. Patients were categorized according to their stage, grade and extent. The absolute survival at 10-, 20-, and 30-year follow-up was calculated for TLP. Kaplan-Meier survival curves were plotted at the tooth-level and multilevel Cox regression frailty models were constructed in order to assess the association among predictive variables and TLP by taking into account the hierarchical patient-teeth structure. RESULTS: 442 patients (11,125 teeth) with a mean follow-up of 23 years met the inclusion criteria and were included in this study. The most prevalent diagnosis at baseline was stage III grade B (30.3%), followed by stage II grade B (23.5%). Among the parameters analysed, stage and grade were found to be the best predictors of TLP. Statistically significant differences were observed for extent only in patients with severe disease (stage IV or grade C). The multilevel Cox regression analysis demonstrated that patients with higher concomitant baseline staging and grading developed greater TLP over the follow-up period. CONCLUSIONS: Higher concomitant staging and grading corresponded to greater risk for TLP and generalized extent only became a significant predictor in patients with stage IV or grade C disease.

Development of a nomogram for the prediction of periodontal tooth loss using the staging and grading system: A long-term cohort study.

AIM: To develop and internally validate a nomogram built on a multivariate prediction model including parameters from the new classification of periodontal diseases, able to predict, at baseline, the occurrence of tooth loss due to periodontal reason (TLP). MATERIALS AND METHODS: A total of 315 individuals diagnosed with periodontal disease and receiving a minimum of one annual supportive periodontal therapy visit were included in the study. Patients were staged and graded based upon baseline data. The population was divided into a development (254 patients) and a validation (61 patients) cohort to allow subsequent temporal validation of the model. According to the TLP at the 10-year follow-up, patients were categorized as "low tooth loss" (≤ 1 TLP) or "high tooth loss" (≥ 2 TLP). Bootstrap internal validation was performed on the whole data set to calculate an optimism-corrected estimate of performance. RESULTS: The generated nomogram showed a strong predictive capability (AUC = 0.81) and good calibration with an intercept = 0 and slope = 1. These findings were confirmed by internal validation using bootstrapping (average bootstrap AUC = 0.83). CONCLUSIONS: The clinical implementation of the present nomogram guides the prediction of patients with high risk of disease progression and subsequent tooth loss for personalized care.

Dose-dependent effect of smoking and smoking cessation on periodontitis-related tooth loss during 10 - 47 years periodontal maintenance-A retrospective study in compliant cohort.

AIM: We retrospectively explored effects of smoking on tooth loss due to periodontitis (TLP) in long-term compliant patients. MATERIALS AND METHODS: Chart data were collected from 258 patients undergoing post-non-surgical periodontal treatment (mean 2.24 visits/year) for 10-47.5 (mean 24.2) years. Patients were categorized as: (1) never smokers, (2) former smokers, (3) current light smokers (<10 cigarettes/day) and (4) current heavy smokers (≥10 cigarettes/day). RESULTS: Of 6,590 teeth present at baseline (mean 25.6 teeth/patient), 264 teeth were lost due to periodontitis, corresponding to 0.03, 0.05, 0.08 and 0.11 TLP annually among never smokers, former smokers, current light smokers and current heavy smokers, respectively. A tooth from a current heavy smoker had 4.4-fold, 2.7-fold and 2.6-fold greater risk of TLP than a tooth from a never smoker, a current light smoker and a former smoker, respectively. Both heavy and light former smokers needed washout periods of approximately 15 years to reach the TLP risk level of never smokers. The TLP risk decreased by 6%/year of smoking cessation. CONCLUSIONS: It took almost 15 years of smoking cessation for the risk of TLP among former smokers to reach the level of never smokers. Hence, the 2018 periodontitis grading system should consider the impact of the "washout" period on former smokers.

Outcomes of root resection therapy up to 16.8 years: A retrospective study in an academic setting.

BACKGROUND: Root resection has been considered a viable treatment option for molars with furcation defects. However, need of a multidisciplinary approach could potentially deem this procedure less successful. The aim of the present article was to determine survival rates of root resection procedure and reasons for failure in an academic setting. METHODS: Patient-related demographic data, medical history information, and relevant data pertaining to the root-resected teeth performed from January 1990 to September 2017 were reviewed through electronic and paper chart. Survival rates were analyzed using Kaplan-Meier estimate. Association between the reasons for failure and independent variables was established by a Pearson Chi-squared and Kruskal-Wallis test. RESULTS: A total of 85 patients with an average follow-up of 5 ± 4.3 years (range: 1 to 16.8 years) were included in the present article. A total of 47 molar teeth treated with root resection remained as part of the dentition (55.3%) and 38 (44.7%) failed. The mean survival time with the Kaplan-Mayer analysis was 109.9 months (9.1 years). Fracture (39.5%), caries (26.3%), and periodontal disease (23.7%) were the most common causes for failure. Interestingly, the majority of failures occurred in the first 4 years after therapy (n = 31; 81.5% of all failures). CONCLUSIONS: Root resection therapy remains a treatment solution for molars with furcation defects. In an academic setting, >50% of teeth remained functional after 9 years of root resection therapy.

Using periodontal staging and grading system as a prognostic factor for future tooth loss: A long-term retrospective study.

BACKGROUND: A new classification of periodontal diseases aimed to identify periodontal disease based on a multidimensional staging and grading system has been recently proposed. However, up to date, its prognostic predictive capability has not been investigated. The aim of this study was to assess if parameters included in the new classification were predictive of tooth loss after a long-term follow-up (>10 years) in patients with periodontitis. METHODS: Patients presented with periodontitis at the University of Michigan between January 1966 and January 2004 were screened and categorized according to the new classification of periodontitis. Number/Reasons of teeth loss in patients who underwent at least one session/year of maintenance during the entire follow-up period were extracted and used to analyze the prognostic capabilities of variables (staging, grading, and Extent) included in the new classification. RESULTS: A total number of 292 patients with a mean follow-up of 289.7 ± 79.6 months were included. 31 (10.6%) patients were classified as Stage 1, 85 (29.1%) as Stage 2, 146 (50%) as Stage 3, and 30 (10.3%) as Stage 4. For grading, 34 (11.7%) were classified as Grade A, 193 (66.1%) as Grade B, and 65 (22.2%) as Grade C. Results of multilevel Cox regression analyses revealed a statistically significant association between stage (HR:3.73 between Stage 4 and Stage 1) and grade (HR: 4.83 between Grade C and Grade A) at baseline and periodontal related tooth loss, whereas no differences were detected for the extent of periodontitis. CONCLUSION: This study provides the initial evidence regarding the predictive ability of the new classification of periodontitis. Patients in either Stage 4 or Grade C showed a significantly higher periodontal-related tooth loss.