Autophagy regulates bone loss via the RANKL/RANK/OPG axis in an experimental rat apical periodontitis model.

AIM: Autophagy is involved in human apical periodontitis (AP). However, it is not clear whether autophagy is protective or destructive in bone loss via the receptor activator of nuclear factor-κB ligand (RANKL)/RANK/osteoprotegerin (OPG) axis. This study aimed to investigate the involvement of autophagy via the RANKL/RANK/OPG axis during the development of AP in an experimental rat model. METHODOLOGY: Twenty-four female Sprague-Dawley rats were divided into control, experimental AP (EAP) + saline, and EAP + 3-methyladenine (An autophagy inhibitor, 3-MA) groups. The control group did not receive any treatment. The EAP + saline group and the EAP + 3-MA group received intraperitoneal injections of saline and 3-MA, respectively, starting 1 week after the pulp was exposed. Specimens were collected for microcomputed tomography (micro-CT) scanning, histological processing, and immunostaining to examine the expression of light chain 3 beta (LC3B), RANK, RANKL, and OPG. Data were analysed using one-way analysis of variance (p < .05). RESULTS: Micro-CT showed greater bone loss in the EAP + 3-MA group than in the EAP + saline group, indicated by an elevated trabecular space (Tb.Sp) (p < .05). Inflammatory cell infiltration was observed in the EAP + saline and EAP + 3-MA groups. Compared with EAP + saline group, the EAP + 3-MA group showed weaker expression of LC3B (p < .01) and OPG (p < .05), more intense expression of RANK (p < .01) and RANKL (p < .01), and a higher RANKL/OPG ratio (p < .05). CONCLUSION: Autophagy may exert a protective effect against AP by regulating the RANKL/RANK/OPG axis, thereby inhibiting excessive bone loss.

New measure of functional tooth loss for successful Oral ageing: a cross-sectional study.

BACKGROUND: This cross-sectional study evaluated the impacts of functional tooth loss on oral health-related quality of life (OHRQoL) among elderly people compared with the impacts of several common indicators of oral health. Additionally, the cut-off of functional tooth loss needed for a better OHRQoL was investigated to establish a new measure for successful oral ageing. METHODS: Data from people aged 65-74 were extracted from the Fourth National Oral Health Survey in Sichuan, China. Functional tooth loss was defined as both natural tooth loss and nonfunctional teeth, such as third molars, residual roots, and removable dentures. The cut-offs of tooth loss were first identified as 12, based on the previous definition of functional dentition (≥20 natural teeth except the third molars), and 14, 16, or 18 for further investigation. OHRQoL was evaluated by the standardized Geriatric Oral Health Assessment Index (sGOHAI) score. Logistic regression was performed to estimate the impacts on OHRQoL. Additionally, subgroup analyses were conducted using the stratified chi-square test to explore the effect of functional tooth loss at each position. RESULTS: The mean GOHAI score of the 744 participants was 48.25 ± 7.62. Elderly people who had lost ≤12 functional teeth had greater odds of reporting a higher sGOHAI score than those who had lost more functional teeth (odds ratio (OR) 1.49, 95% confidence interval (CI) 1.05-2.11). No significant difference in the sGOHAI score was detected between people who had lost 13-16 functional teeth and those who had lost ≤12 functional teeth (0.61, 0.35-1.07). The loss of second premolars and first and second molars had great impacts on the sGOHAI score when ≤12 or ≤ 16 functional teeth had been lost. CONCLUSIONS: Compared with natural tooth loss, functional dentition and occluding pairs, functional tooth loss can be a better indicator of OHRQoL in the elderly population. Sixteen remaining functional teeth seem to be sufficient to maintain good OHRQoL and successful oral ageing despite that number being previously acknowledged as ≥20 teeth.

An economic evaluation of pit and fissure sealants and fluoride varnishes in preventing dental caries: a systematic review.

The aim was to systematically evaluate the cost-effectiveness of pit and fissure sealants (PFSs) compared with that of fluoride varnishes (FVs) in dental caries prevention. We searched four electronic databases including the Cochrane Oral Health Group's Trials Register (till 03 June 2022), Web of Science (from 1945 to 03 June 2022), PubMed (from 1996 to 03 June 2022), and EMBASE via Ovid (from 1980 to 03 June 2022) to identify the cost and effectiveness of PFSs and FVs in decreasing dental caries incidence. Two researchers independently screened search results, extracted data from the included studies, and conducted the risk of bias assessments. The main characteristics of the included studies were extracted and analyzed. The initial search produced 874 articles. After removing duplicates and full-text review, 19 studies were included. In this study: nine studies were on PFSs comparison with control; five on PFSs comparison with FVs; and five on FVs comparison with control. Regarding the type of economic evaluation (EE), 13 studies conducted cost-effectiveness analysis, five conducted cost-utility analyses, and one conducted both cost-effectiveness analysis and cost-utility analyses. The cost-effectiveness evaluation of PFSs and FVs in the available studies was limited. The prevalence of dental caries, payers' willingness to pay, length of follow-ups, delivery settings, retention rate of PFS, and application intervals of FV can affect the economic evaluation of these two methods for dental caries prevention. Therefore, more studies in the future are need to draw clear conclusions about which method is more cost-effective for the two preventive interventions in future.

A predictive nomogram: a cross-sectional study on a simple-to-use model for screening 12-year-old children for severe caries in middle schools.

BACKGROUND: A nomogram is a tool that transforms complex regression equations into simple and visual graphs and enables clinicians and patients to conveniently compute output probabilities without needing medical knowledge and complex formulas. The aim of this study was to develop and validate a predictive nomogram to screen for severe caries among 12-year-old children based on risk factors in Sichuan Province, China. METHODS: A cross-sectional study of 4573 12-year-olds was conducted up to May 2016 in middle schools from three districts and three counties in Sichuan Province, China. All the children underwent oral examinations and completed questionnaires to assess general information, oral impacts on daily performance, dietary habits, subjective health conditions, history of dental trauma, frequency of toothache, dental visits, and knowledge, attitudes, and behaviours toward oral hygiene. Univariate analysis and multivariate logistic regression analysis were used to determine which variables were significantly associated with severe caries (operationalized as DMFT ≥ 3). A nomogram was developed and validated by using the 'rms' package and two cross-validation methods. RESULTS: Severe caries was found in 537 of the 4573 children (11.74%). Multivariate logistic regression analysis revealed that the following variables predicted a higher risk of severe caries: 'female' [odds ratio (OR) = 1.985, 95% confidence interval (95% CI): 1.63-2.411], 'urban' (OR = 2.389, 95% CI: 1.96-2.91), 'non-only child' (OR = 1.317, 95% CI: 1.07-1.625), 'very poor self-assessment of oral health status' (OR = 2.157, 95% CI: 1.34-3.467) and 'visited a dentist less than 6 months' (OR = 1.861, 95% CI: 1.38-2.505). Multivariate logistic regression analysis also indicated that the following variables predicted a lower risk of severe caries: 'middle level of urbanization' (OR = 0.395, 95% CI: 0.32-0.495) and 'high level of urbanization' (OR = 0.466, 95% CI: 0.37-0.596). Both the fivefold and leave-one-out cross-validation methods indicated that the nomogram model built by these 6 variables displayed good disease recognition ability. CONCLUSIONS: The nomogram was a simple-to-use model to screen children for severe caries. This model was found to facilitate non-dental professionals in assessing risk values without oral examinations and making referrals to dental professionals.