Tooth loss during supportive periodontal care: A prospective study.

AIM: To assess periodontal stability and the association between tooth- and patient-related factors and tooth loss during supportive periodontal care (SPC). MATERIALS AND METHODS: A prospective observational study was carried out on previously treated periodontitis patients followed up for 5 years in SPC. The risk profile (low, moderate, high) of each patient based on periodontal risk assessment (PRA) scoring at baseline was evaluated, and tooth loss rates were analysed. RESULTS: Two hundred patients were included in the study, and 143 had 5-year follow-up data available for analysis. The overall annual tooth loss per patient was 0.07 ± 0.14 teeth/patient/year. Older age, smoking, staging and grading were associated with increased tooth loss rates. Most patients whose teeth were extracted belonged to the PRA high-risk group. Both PRA and a tooth prognosis system used at baseline showed high negative predictive value but low positive predictive value for tooth loss during SPC. CONCLUSIONS: Overall, the tooth loss rate of periodontitis patients in this prospective cohort study under SPC in private practice was low. Both tooth-based and patient-based prognostic systems can identify high-risk cases, but their positive predictive value should be improved.

Convolutional Neural Network-Based Pattern Recognition of Partial Discharge in High-Speed Electric-Multiple-Unit Cable Termination.

Partial discharge detection is considered a crucial technique for evaluating insulation performance and identifying defect types in cable terminals of high-speed electric multiple units (EMUs). In this study, terminal samples exhibiting four typical defects were prepared from high-speed EMUs. A cable discharge testing system, utilizing high-frequency current sensing, was developed to collect discharge signals, and datasets corresponding to these defects were established. This study proposes the use of the convolutional neural network (CNN) for the classification of discharge signals associated with specific defects, comparing this method with two existing neural network (NN)-based classification models that employ the back-propagation NN and the radial basis function NN, respectively. The comparative results demonstrate that the CNN-based model excels in accurately identifying signals from various defect types in the cable terminals of high-speed EMUs, surpassing the two existing NN-based classification models.

Comparison of the efficacy of periodontal prognostic systems in predicting tooth loss.

AIM: The aim of this analysis was to assess how different tooth-prognosis systems could predict tooth loss in a cohort of periodontitis patients followed up prospectively during supportive periodontal care (SPC). MATERIALS AND METHODS: Clinical and radiographic data of 97 patients undergoing regular SPC for 5 years were used to assign tooth prognosis using four different systems (McGuire & Nunn, 1996; Kwok & Caton, 2007; Graetz et al., 2011; Nibali et al., 2017). Three independent examiners assigned tooth prognosis using all four systems, following a calibration exercise. The association between prognostic categories and tooth loss was tested for each prognostic system separately and across prognostic systems. RESULTS: All four systems showed good reproducibility and could identify teeth at higher risk of being lost during 5 years of SPC; the risk of tooth loss increased with the worsening of tooth-prognosis category (p < .0001). Although specificity and negative predictive values were good, low sensitivity and positive predictive values were detected for all systems. CONCLUSIONS: Previously published periodontal prognostic systems exhibited good reproducibility and predictive ability for tooth retention. However, low sensitivity was detected, with several teeth in the worst prognosis category being retained at 5 years. Some modifications in the number of categories and their definitions are suggested.

The effect of horizontal and vertical furcation involvement on molar survival: A retrospective study.

BACKGROUND: Periodontal involvement of the furcation area (furcation involvement, FI) has been reported to confer molars a higher risk of tooth loss. AIMS: The aim of this retrospective analysis was to assess the effect of FI on disease progression and tooth loss in molars of patients with chronic periodontitis undergoing supportive periodontal therapy (SPT) in a UK private practice setting. MATERIALS AND METHODS: Six-hundred and thirty-three molars were analysed in 100 chronic periodontitis patients treated with active periodontal therapy (APT) and followed up in SPT for at least 5 years. Molars were treated with a combination of resective, regenerative or conservative approaches, according to the different clinical needs. RESULTS: Twenty-three molars were extracted during APT and a further 23 were lost during SPT. Multivariable analysis showed that both horizontal FI and vertical furcation component were associated with increased risk of tooth loss during SPT (OR 5.26, 95% CI: 1.46-19.03, p = .012 and OR 9.83, 95% CI: 1.83-50.11, p = .006, respectively). CONCLUSION: Attention should be placed on both horizontal and vertical FI in molars, owing to their association with tooth loss during SPT.

A retrospective study on periodontal disease progression in private practice.

BACKGROUND: Only a handful of studies have assessed tooth loss risk in chronic periodontitis patients following active therapy and factors associated with it. AIMS: The aim of this retrospective study was to assess tooth loss in a cohort of chronic periodontitis patients undergoing maintenance care in a UK private practice setting. MATERIALS AND METHODS: One hundred chronic periodontitis patients treated with active periodontal therapy were followed up in supportive periodontal therapy (SPT) for at least 5 years. Tooth loss rates and the effect of patient and tooth factors on tooth loss were assessed. Existing patient-based prognosis systems and a novel tooth-based prognosis system were tested for their association with tooth loss. RESULTS: Excluding third molars, 34 teeth were extracted during SPT, with an overall average tooth loss of 0.06 teeth/patient/year (0.02 for periodontal reasons). Multivariable analysis showed that age, patient prognosis based on the Periodontal Risk Assessment system, tooth prognosis, furcation involvement and previous endodontic therapy were significantly associated with tooth loss during SPT. CONCLUSION: Good overall stability and a small tooth loss rate were observed in this cohort of chronic periodontitis cases under SPT in private practice. Patient-based and tooth-based prognosis systems may be used to estimate the risk of tooth loss.

What is the effect of soft tissue thickness on crestal bone loss around dental implants? A systematic review.

OBJECTIVES: The aim of this systematic review was to determine whether soft tissue biotype at implant placement has an influence on crestal bone loss (CBL) at 1 year after implant loading. MATERIAL AND METHODS: Following electronic search in three databases (MEDLINE via OVID, EMBASE and The Cochrane Database) and hand search up to April 2015, two reviewers screened independently and in duplicate the references to identify randomized controlled trials, controlled clinical trials (CCTs) and prospective case series eligible for systematic review and meta-analysis. Cochrane Collaboration's tool was used for assessing risk of bias. RESULTS: From 2944 citations, six studies (6 CCTs) met the inclusion criteria. Four of six individual studies that compared thin vs. thick biotype showed significantly higher CBL in thin biotype. Meta-analysis could only be performed with two studies and the differences did not reach significant level. None of the included studies was of low risk of bias. CONCLUSIONS: At present, there is insufficient evidence to answer the question on the differences in clinical outcome in terms of CBL between implants placed in sites with initial soft tissue thickness <2 mm and those with ≥2 mm. Further, well-designed controlled clinical studies are needed to analyze the effect of soft tissue thickness on the clinical outcomes of dental implants.

[Periodontal tissue in a bio-implant by periodontal ligament cells sheet and bone marrow stromal cells sheet].

OBJECTIVE: To fabricate the bio-implant supported by regenerated periodontal tissue utilizing periodontal ligament cells (PDLC)-bone marrow stromal cells (BMSC) sheet and natural root. METHODS: Premolars of 2 beagle dogs were extracted to prepare the implanted area. Autologous tooth roots were carved into cylinders. PDLC and BMSC separated from beagle dogs were cultured into cell sheets in medium. Tooth roots were wrapped by one type of cell sheets or both to fabricate bio-implant and divided into four groups, tooth roots were wrapped by PDLC sheets and BMSC sheets successively (2 samples each dog), tooth roots were wrapped by PDLC sheets alone (2 samples each dog), tooth roots were wrapped by BMSC sheet alone (2 samples each dog), tooth roots without cell sheet (1 sample each dog). The implants were implanted into the mandibles. The mandibles were dissected 12 weeks later, sliced and stained by HE and Masson dyes for histological examination. RESULTS: In the PDLC cell sheet/root implants, histological examination revealed that new periodontal-like tissue including cementum, periodontium and alveolar bone was regenerated.In the BMSC implants, tooth ankylosis was observed. CONCLUSIONS: PDLC sheet and natural root can be used to fabricate bio-implant. PDLC sheet could promote periodontal regeneration.