Differences in periodontal parameters between SPT patients who regularly and irregularly visited the dental clinic analyzed at tooth level: a 14-year retrospective cohort study.

The purpose of this study was to evaluate the periodontal status of patients who routinely did SPT, when compared to patients that did not SPT. This retrospective cohort study was conducted at a general dental office from 2001 to 2019. Patients aged 18 to 81 years who visited the dental office over a 10-year period were assigned into two groups: an SPT group, which included patients who continually visited the dental office for SPT one or more times every year, and an irregular group, consisting of patients who did not visit the dental office at least once a year. A total of 7307 teeth (SPT group) and 4659 teeth (irregular group) were evaluated, and the periodontal conditions were compared between the first and latest visits. Multiple regression analysis was used to analyze the results. The mean follow-up time was 13.74 years. The risk factors for improvements in probing pocket depth included age, sex, smoking, diabetes mellitus, molar tooth, and irregular SPT group (p < 0.001), and that for a positive bleeding on probing site was the irregular group (odds ratio 2.94; 95% confidence interval 2.63-3.29). This study showed that lack of routine in attending the SPT program significantly decreased the periodontal parameters, thus highlighting the importance of continuing with the program to maintain the periodontal health.

Risk factors for tooth loss with a mean follow-up period of 13.9 years in supportive periodontal therapy patients.

BACKGROUND: Clinical evidence indicates that there are various risk factors of tooth loss. However, the degree of this risk among other risk factors remains unclear. In this retrospective cohort study, the authors evaluated the hazard ratios of several risk factors for tooth loss. METHODS: Included patients had all been treated for dental disorders, were in the supportive phase of periodontal therapy by dental hygienists, and visited a Japanese dental office continually during a 10-year period. Periodontal parameters, tooth condition, and general status of all teeth (excluding third molars) at the initial visit and at least 10 years later were evaluated by using multiple classification analysis. RESULTS: The authors evaluated a total of 7584 teeth in 297 patients (average age: 45.3, mean follow-up time: 13.9 years) Non-vital pulp was the most significant predictor of tooth loss according to Cox hazards regression analysis (hazard ratio: 3.31). The 10-year survival rate was approximately 90% for teeth with non-vital pulp and 99% for teeth with vital pulp. Fracture was the most common reason for tooth loss. CONCLUSIONS: Non-vital pulp had the most significant association with tooth loss among the parameters. Therefore, it is very important to minimize dental pulp extirpation.

Relationship between periodontal parameters and non-vital pulp in dental clinic patients: a cross-sectional study.

BACKGROUND: Endodontic diseases, such as apical periodontitis, communicate with periodontitis and mutually exacerbate them. However, it remains unclear whether pulp condition is a risk factor for periodontal disease. The purpose of this retrospective study was to examine relations between pulp condition and periodontal parameters in Japanese patients who visited a general dental clinic. METHODS: Patients who visited a Japanese general dental clinic from 2016 to 2018 and aged 18 to 81 years were analyzed. Periodontal parameters, tooth condition, and general status of all teeth excluding third molars at the initial visit to the clinic were abstracted. A total of 7105 teeth were analyzed in this study by multiple classification analysis and the Mann-Whitney U test. We also performed a sub-analysis of non-vital teeth, which evaluated the presence or absence of unfavorable root canal obturation and apical periodontitis diagnosed by X-ray. RESULTS: Significant relations between periodontal parameters and non-vital pulp were observed by multiple logistic regression analyses (odds ratio = 1.48; 95% CI = 1.03-2.14) and multiple linear regression analysis (p < 0.001). Significant relations between unfavorable root canal obturation tooth with periodontal pocket depth (p = 0.00837) and BOP (p = 0.0145) were also observed by the Mann-Whitney U test. CONCLUSIONS: We demonstrated potential relations between periodontal disease and non-vital pulp.

Observation of the synchronization of chaos in mutually injected vertical-cavity surface-emitting semiconductor lasers.

Synchronization of chaotic oscillations was observed in mutually injected vertical-cavity surface-emitting lasers (VCSELs) in a low-frequency fluctuation regime. In the experiments, only one of the two polarization modes (x mode) showed synchronized oscillations, and the other polarization components (y mode) were synchronized as a result of the effect of anticorrelated oscillations that is a characteristic feature of VCSELs.

Observation of low-frequency fluctuations in vertical-cavity surface-emitting lasers.

Low-frequency fluctuations, which are typical irregular oscillations in edge-emitting semiconductor lasers, are experimentally observed for the y-polarization mode (y is the direction along the optical axis of a laser material) in a vertical-cavity surface-emitting laser with optical feedback.