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.

[Comparison of dentinal microcracks caused by new generation of single reciprocating files after root canal preparation].

PURPOSE: To compare the incidence of dentinal microcracks after root canal preparation by new generation of nickel-titanium instrument WaveOne Gold, Reciproc Blue with previous WaveOne and Reciproc. METHODS: Ninety extracted single-rooted mandibular premolars were randomly divided into 6 groups(n=15). The root canals were instrumented by using Hand K files, WaveOne, Reciproc, WaveOne Gold and Reciproc Blue. Fifteen teeth were left unprepared and served as negative controls. The root canals were all prepared to 25#. The roots were then sectioned at 3 mm, 6 mm and 9 mm from the apical orifice using a hard tissue slicer. The slices were observed under stereoscopic microscope at ×25 magnification. SPSS 17.0 software package was used for statistical analysis. RESULTS: No dentinal microcrack was found in the hand K files group and negative control group. The reciprocating single files WaveOne, WaveOne Gold, Reciproc and Reciproc Blue all produced dentinal microcracks after root canal preparation. The WaveOne generated the most dentinal microcracks than the hand K files(P＜0.05), and the microcracks were mainly concentrated in the middle part of the root. The number of dentinal microcracks caused by Reciproc and Reciproc Blue was the same, with no significant difference(P＞0.05). CONCLUSIONS: The new generation of reciprocating files of WaveOne Gold and Reciproc Blue may not increase the incidence of dentinal microcracks after root canal preparation.

Utilization of dental care service and associated factors among pre-school children in northwest China over the past decade.

OBJECTIVE: The purpose of this study was to analyze the factors influencing the utilization of oral health care among 5 years old children. METHODS: We conducted two observational cross-sectional studies. The studies were conducted in 2005 and 2015 and included 5-year-old children who underwent dental examination by trained dentists and the caregivers of the children were requested to answer the questionnaire. Multi-level stratified sampling method was used. Chi-square tests were used to analyze the utilization of dental care and other socio-economic variables. Logistic regression models were employed to explore the primary factors influencing the use of dental care among pre-school children. RESULTS: In 2005, a total of 399 and in 2015, 492 child-caregiver pairs were included. The majority of the caregivers in both surveys were females, comprising 68.2% and 74.8% of the caregivers in 2005 and 2015, respectively. 75.2% and 87.0% (p < 0.05) of the respondents had an education level of lesser than 9 years. The prevalence of caries was higher in 2015 (63.2%) (p < 0.05) than in 2005 (53.4%). In 2005 and 2015, the utilization of dental care services was 20.8% and 20.0%, respectively. A statistically significant association was observed between caries and dental care use in 5-year-olds over the past decade. After adjusting for confounders, dental service usage among children in urban areas was 1.62 times higher than that of rural areas in 2005 (95% CI 0.069-0.571), and the self-assessment of caregivers regarding their child's oral health significantly improved oral health use in 2015. CONCLUSION: The utilization of dental care services over the past decade is insufficient among pre-school children in northwest China. Hence, with the decreasing gap about economic and health service resources, policymakers should place greater emphasis on raising awareness among caregivers about the oral health status of their children.

Novel antimicrobial agents targeting the Streptococcus mutans biofilms discovery through computer technology.

Dental caries is one of the most prevalent and costly biofilm-associated infectious diseases worldwide. Streptococcus mutans (S. mutans) is well recognized as the major causative factor of dental caries due to its acidogenicity, aciduricity and extracellular polymeric substances (EPSs) synthesis ability. The EPSs have been considered as a virulent factor of cariogenic biofilm, which enhance biofilms resistance to antimicrobial agents and virulence compared with planktonic bacterial cells. The traditional anti-caries therapies, such as chlorhexidine and antibiotics are characterized by side-effects and drug resistance. With the development of computer technology, several novel approaches are being used to synthesize or discover antimicrobial agents. In this mini review, we summarized the novel antimicrobial agents targeting the S. mutans biofilms discovery through computer technology. Drug repurposing of small molecules expands the original medical indications and lowers drug development costs and risks. The computer-aided drug design (CADD) has been used for identifying compounds with optimal interactions with the target via silico screening and computational methods. The synthetic antimicrobial peptides (AMPs) based on the rational design, computational design or high-throughput screening have shown increased selectivity for both single- and multi-species biofilms. These methods provide potential therapeutic agents to promote targeted control of the oral microbial biofilms in the near future.

Pellino-1 Protects Periodontal Ligament Stem Cells Against H2O2-Induced Apoptosis via Activation of NF-κB Signaling.

To determine the protective effects of Pellino-1 against H2O2-induced apoptosis in periodontal ligament stem cells (PDLSC). We demonstrated that H2O2 decreases PDLSC viability by 40 and 50% with the concentrations of 400 and 500 µM, respectively, with an observed downregulation of Pellino-1 mRNA and protein; we further concluded that overexpression of Pellino-1 significantly lowers 8-hydroxy-2'-deoxyguanosine levels by 10% and upregulates superoxide dismutase 1, glutathione peroxidase levels, and catalase mRNA levels by 200, 40, and 250%, respectively. More importantly, we found that overexpression of Pellino-1 inhibited H2O2-induced cellular apoptosis through the activation of the NF-κB signaling pathway. Pellino-1 may be critically important for cell survival in the presence of oxidative elements; activation of the NF-κB signaling cascade was required for the overexpression of Pellino-1 to protect the cells from H2O2-induced apoptosis.

Inhibition of WNT7A-ß-catenin signaling pathway sensitizes oral squamous cell carcinoma to cisplatin.

Oral squamous cell carcinoma (OSCC) is the most common type and most threatening head and neck cancer worldwide. Here, we aim to study the relationship between the WNT7A-ß-Catenin signaling pathway and the chemotherapy resistance of OSCC patients. We analyzed 42 OSCC patients and 19 adjacent non-tumor tissues, evaluated the expression levels of WNT7A mRNA, and subsequently studied WNT7A dependent cisplatin resistance in OSCC cell line KB cells. Moreover, we also utilized an in vivo mouse model to validate our findings. We first found a significant upregulation of WNT7A mRNA in OSCC patients. Our results showed that the knockdown of WNT7A sensitized KB cells to cisplatin. Moreover, our results revealed that nuclear ß-catenin was dramatically reduced and cleaved caspase-3 and cleaved PARP were dramatically induced when WNT7A was knocked down in cisplatin treated KB cells. Besides, we found that the knockdown of WNT7A significantly reduced the weight and volumes of xenograft tumors. Moreover, we examined apoptotic cells and found that the combination of WNT7A knockdown and cisplatin treatment resulted in many more apoptotic cells than cisplatin treatment alone, suggesting that the knockdown of WNT7A sensitized KB cells to cisplatin treatment in vivo. Our results revealed that inhibition of WNT7A-ß-catenin signaling sensitizes OSCC to cisplatin, which has provided insights into the molecular diagnosis and treatment of OSCC.

[Effects of fluoride on expression of survivin during rats' dental germ development].

PURPOSE: This study was to investigate the expression of survivin in dental germ development of SD rats with fluorosis, and explore the effects of fluoride on survivin expression and the pathogenic mechanism of dental fluorosis. METHODS: Forty-five SD rats (pregnant for 10 days) were randomly divided into control group, experimental group 1 and group 2. Drinking water with fluoride concentration of 0, 50, 150 mg/L was provided for rats accordingly. The samples were collected at E18.5th day, E20.5th day, P1.5th day, P3.5th day and P5.5th day, then the samples of P1.5th day were selected for H-E staining. SABC method was used for immunohistochemical analysis of samples in each group. The images were acquired by Motic Med 6.0 digital medical image analysis system, and the data were analyzed for ANOVA with SPSS 13.0 software package. RESULTS: Survivin expression fluctuated and exhibited 'M' shape (rose first and fell later) in each group.There was no significant difference at E18.5th day (F=1.050, P>0.05) and E20.5th day (F=2.232, P>0.05) between each group. There were significant differences at P1.5th day (F=3.538, P<0.05), P 3.5th day (F=3.820, P<0.05) and P5.5th day (F=5.096, P<0.05) between the control and experimental groups. The postnatal rats in each group were evaluated by SNK method for surviving expression. There was no significant difference between control group and experimental group 1 (P>0.05). However, there was significant difference between control group and experimental group 2 (P<0.05). CONCLUSIONS: The results suggest that fluoride can decrease the expression of survivin in the postnatal rats with higher fluoride concentration, which may be the mechanism in the development of dental fluorosis.

Different expression patterns of Lin28 and Lin28b in mouse molar development.

OBJECTIVE: The RNA-binding proteins Lin28 and Lin28b are expressed in many developing tissues and are involved in the biosynthesis of the microRNA let-7 family and embryogenesis processes. However, their roles in mammalian tooth development remain ill-defined. DESIGN: The spatiotemporal expressions of Lin28 and Lin28b during mouse molar odontogenesis from day E11.5 to P21 were examined through immunohistochemistry and western blot analysis. RESULTS: Both Lin28 and Lin28b were initially expressed in dental epithelium, but the expression patterns varied thereafter. Lin28 was expressed in tooth germ from early embryonic stages and was consistently expressed in the ameloblasts and odontoblasts throughout all stages of tooth development. However, positive staining of Lin28b gradually faded out with tooth germ development, before finally disappearing in tooth organ cells after birth. CONCLUSIONS: These results indicate that Lin28 was spatiotemporally expressed in tooth germ throughout tooth development progression and may play an active role in ameloblast and odontoblast differentiation, as well as matrix secretion and the mineralization of enamel and dentin. Its paralogue Lin28b may have a distinct function in tooth germ formation.

Oral health status and oral health knowledge, attitudes and behavior among rural children in Shaanxi, western China: a cross-sectional survey.

BACKGROUND: The current oral health status and possible dental risk factors among children in rural Shaanxi Province, western China are unreported. This study aimed to describe the oral health status and to analyze the possible risk factors for the oral health status in this population. METHODS: A multi-stage cluster sampling method was used to survey 12- to 15-year-olds and 4- to 6-year-olds in villages in Shaanxi Province. The structured questionnaires were provided to the 12- to 15-year-olds and to the caregivers of the 4- to 6-year-olds to collect information on the subjects' oral health knowledge, attitudes and behavior. A clinical examination was performed to assess dental caries and gingival bleeding (only 12- to 15-year-olds). SPSS 17.0 statistical software was used to analyze the data. RESULTS: The decayed, missing, filled teeth (DMFT) index scores of 12- to 15-year-olds and 4-to 6-year-olds averaged 0.45 and 3.05, respectively. The caries prevalence was 23.9% in 12- to 15-year-olds and 67% in 4-to 6-year-olds. Additionally, 45.2% of the 12- to 15-year-olds had gingival bleeding and 62.8% had calculus. The oral health knowledge of the subjects was generally poor, whereas they held very positive attitudes toward oral health. A low number of participants reported that they brushed their teeth at least twice daily. Moreover, a statistically significant relationship was found between oral health knowledge scores, tooth brushing frequency and DMFT scores as well as gingival bleeding in the 12- to 15-year-olds. Frequency of sweets consumption was strongly related to dmft scores in the 4- to 6-year-olds. CONCLUSION: The oral health status, oral health knowledge and behaviors among village children in Shaanxi Province are poor. Oral health education to improve oral health knowledge and to increase the frequency of tooth brushing should be undertaken in the rural schools in western China.

[Observation on therapeutic effect of round-sharp needle of new nine-needle and elongated needle for piriformis syndrome with triple puncture method].

OBJECTIVE: To compare the efficacy differences between round-sharp needle of new nine-needle and elongated needle for piriformis syndrome, and explore its action mechanism. METHODS: Eighty cases were randomly divided into a round-sharp needle of new nine-needle group (round-sharp needle group) and an elongated needle treatment group (elongated needle group), 40 cases in each group. The round-sharp needle group was treated with round-sharp needle (0.60 mm x 125 mm) at three points in piriformis with triple puncture method, while the elongated needle group was treated with elongated needle of ordinary specifications (0.32 mm x 125 mm) at three points in piriformis with triple puncture method. Besides, the two groups were also treated with routine acupuncture at Weizhong (BL 40) and Yanglingquan (GB 34), 3 times every week, 2 weeks as one course of treatment. After one course of treatment, the clinical effect was evaluated and the pain threshold values were measured before and after treatment in the two groups. RESULTS: The total effective rate in the round-sharp needle group was 92.5% (37/40), which was superior to 77.5% (31/40) in the elongated needle group (P < 0.05). Compared before treatment, the pain threshold values after treatment in two groups were improved significantly (both P < 0.01). The increment of pain threshold value in the round-sharp needle group was higher than that in the elongated needle group (P < 0.01). CONCLUSION: Round-sharp needle of new nine-needle is effective in treatment of piriformis syndrome and is better than ordinary elongated needle, which is related to that it can effectively increase pain threshold value of the local tissue.

[A study of oral health behaviors among 65 to 74 years old people in Shanxi province].

PURPOSE: To assess the oral health behaviors among 65 to 74 years old people in Shanxi province, and provide a base line for oral health service. METHODS: Four hundred and five old people aged from 65 to 74 in Shaanxi province was selected according to the Third National Oral Health Investigation Criteria and the oral health behaviors of them were investigated by questionnaire. SPSS 13.0 software package was used for statistical analysis. RESULTS: Of the participates, 14.3%, 6.6%, 39.5% of old people ate dessert, candy/chocolate, sugar-containing dairy products every day, and 27.5%, 17.0%, 0.7%, 0.5% drank fresh fruit, saccharine, fruit juice, carbonated drinks once daily, respectively. Compared with the rural areas,the proportion of people who drank fresh fruit or ate dessert, sugar-containing dairy products once daily was higher in the urban area (P<0.01). The proportion of people who significantly smoked cigarette, drank alcohol, or drank tea every day was 31.4%, 33.8% and 70.6%, respectively. Smoking and tea consumption were more prevalent in the urban area as well as in males(P<0.01). No difference was found between the prevalence of drinking alcohol in the urban and rural area(P>0.05), but more males drank alcohol than females(P<0.01). 55.8% of people brushed their teeth more than one time a day. Among the investigated people, about 80% never used the toothpick;only 0.7% of them used dental floss;About 30% of the investigated people used fluorine-contained toothpaste, more of them in the urban areas (P<0.01). Fluorine toothpaste usage was 29.1%, significant difference was found between in the urban and rural area (P<0.01), but no significant difference was noted between in males and females(P>0.05). CONCLUSION: Oral health behaviors of 65 to 74 years old people in Shanxi province is irrationality, and needs to be adjusted and improved.