Prevalence, clinical characteristics, and 3-dimensional radiographic analysis of supernumerary teeth in Guangzhou, China: a retrospective study.

OBJECTIVE: The aim was to investigate the prevalence and clinical and 3-dimensional (3D) radiographic characteristics of supernumerary teeth (ST) in a paediatric dental population. The factors associated with ST eruption potential were analysed, and the optimal extraction time for nonerupted ST was discussed. METHODS: A retrospective study was performed in a 13,336-participant baseline population aged 3-12 years for whom panoramic radiographs had been obtained in the hospital from 2019 to 2021. The medical records and radiographic data were reviewed to identify patients with ST. Both the demographic variables and ST characteristics were recorded and analysed . RESULTS: In total, 890 patients with 1,180 ST were screened from the 13,336 baseline population. The ratio of males (679) to females (211) was approximately 3.2:1. Generally, ST occurred singularly and were frequently found in the maxilla (98.1%). A total of 40.8% of ST were erupted, and the 6-year-old age group presented the highest eruption rate (57.8%). The eruption rate of ST was highly negatively correlated with age. A total of 598 patients additionally underwent cone- beam computed tomography (CBCT). According to the CBCT images, the majority of ST were conical, normally oriented, palatally situated, nonerupted and symptomatic. The most common ST-associated complication was failed eruption of adjacent teeth. In addition, symptomatic ST were more common in the 7- to 8- and 9- to 10-year-old age groups. The eruption rate of ST was 25.3% among the patients who had undergone CBCT. A normal orientation and the labial position were significant protective factors for ST eruption, with odds ratios (ORs) of 0.004 (0.000-0.046) and 0.086 (0.007-1.002), respectively. Age and the palatal position were significant risk factors, with ORs of 1.193 (1.065-1.337) and 2.352 (1.377-4.02), respectively. CONCLUSIONS: This study provides a detailed analysis of ST characteristics in 3-12 year old children. Age as well as the position and orientation of ST were reliable predictors of the ST eruption. An age of 6 years old may be the optimal time for extraction of nonerupted ST to maximize the utilization of eruption potential and reduce the incidence of ST-associated complications.

The impact of caries status on supragingival plaque and salivary microbiome in children with mixed dentition: a cross-sectional survey.

BACKGROUND: Supragingival plaque and saliva are commonly used for microbiome analysis. Many epidemiological studies have identified deciduous teeth caries as a risk factor for caries development in first permanent molar (FPM); nevertheless, to the best of our knowledge, there are no reports on the effects of deciduous teeth caries on the microbiome of healthy FPM. Additionally, it remains unclear whether saliva can be used instead of supragingival plaque for caries microbial studies. Therefore, we aimed to elucidate this issue, and to characterize and compare the oral microbiome of healthy FPMs in children with different caries statuses and that from children with and without caries in a similar microhabitat, by PacBio sequencing. Currently, few studies have investigated the oral microbiome of children using this technique. METHODS: Thirty children (aged 7-9 years) with mixed dentition were enrolled; 15 had dental caries, and 15 did not. Supragingival plaques of deciduous molars and maxillary FPMs, and non-stimulating saliva samples were collected. DNA was extracted and the v1-v9 regions of 16S rRNA were amplified. Subsequently, PacBio sequencing and bioinformatic analyses were performed for microbiome identification. RESULTS: The microbial alpha diversity of the saliva samples was lower than that of the supragingival plaque (p < 0.05); however, no differences were detected between deciduous teeth and FPMs (p > 0.05). In addition, the alpha and beta diversity of children with and without caries was also similar (p > 0.05). Nonmetric multidimensional scaling and Adonis analyses indicated that the microbial structure of salivary and supragingival plaque samples differ (p < 0.05). Further analysis of deciduous teeth plaque showed that Streptococcus mutans, Propionibacterium acidifaciens, and Veillonella dispar were more abundant in children with caries than in those without (p < 0.05); while in FPMs plaque, Selenomonas noxia was more abundant in healthy children (p < 0.05). No differences in microorganisms abundance were found in the saliva subgroups (p > 0.05). CONCLUSION: We have determined that supragingival plaque was the best candidate for studying carious microbiome. Furthermore, S. mutans, V. dispar, and P. acidifaciens were highly associated with deciduous teeth caries. S. noxia may be associated with the abiding health of FPM; however, this requires additional studies.

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The 16S rRNA gene is the most commonly used molecular marker for identifying microorganisms. It is used in sequencing technology, including the first-generation, the second-generation, and the third-generation sequencing technology. A large number of studies on the 16S rRNA gene have contributed to a deeper understanding of oral microbial diversity. In the healthy oral cavity, there is microbial diversity in time and space. With the occurrence or development of oral diseases such as caries, periodontal disease, or halitosis, the microbial diversity will be changed.

[Correlation between children's dental decay and the contents of saliva CCL28 and secretory immunoglobulin A].

OBJECTIVE: To explore the association of the dental decay of children with the contents of chemokine CCL28 and secretory immunoglobulin A (sIgA) in saliva. METHODS: A total of 108 children in 2 kindergartens of Changsha, with age from 3 to 5 years old, were enrolled for this study. The saliva was collected from these children when they were in the examination of mouth. Th e children were divided into 3 groups: A non-caries group [dynamical mean-field theory (DMFT)=0], a low caries group (DMFT=1-4) and a high caries group (DMFT ≥ 5). Th e contents of CCL28 and sIgA were measured by ELISA. RESULTS: The contents of CCL28 and sIgA in saliva were (121.22 ± 32.63) pg/mL and (16.49 ± 8.02) µg/mL, respectively. A positive linear correlation was found between the CCL28 content and sIgA content in saliva (r=0.734). Th e CCL28 and sIgA contents in saliva were positively correlated with the degree of dental caries in children (P<0.05). CONCLUSION: The dental decay of children leads to the secretion of chemokine CCL28, which promotes the secretion of sIgA in saliva.

Effectiveness of online caries management platform in children's caries prevention: A randomized controlled trial.

Purpose: To construct an online caries management platform and evaluate its efficacy in children's caries prevention based on caries risk. Methods: The study participants were second-grade pupils. The caries risk assessment tool (CAT) was used to grade caries risk for all participants, who were randomly divided into the experimental (114 pupils) and control (111 pupils) groups. The experimental group used the Internet for caries management, while the control group was managed by traditional lecturing in classroom. The caries status of each surface of the first permanent molars was recorded. The basic information and oral health knowledge, attitude, and behaviors of participants were collected by questionnaire. One year later, outcome data were collected. Pearson's chi-squared test was used to analyze the caries risk assessment items and oral health behaviors. The Mann-Whitney U-test was used to analyze the decayed-missing-filled surfaces (DMFS) index, plaque index, and scores of oral health knowledge and attitude. P < 0.05 was considered statistically significant. This study was available on the website of Chinese Clinical Trials Register (No: MR-44-22-012947). Results: After 1 year, the oral health knowledge score was improved by 20.58% (P < 0.001) in the experimental group and 6.02% in the control group. The plaque index was improved by 49.60% (P < 0.001) in the experimental group and 21.01% in the control group. The DMFS index increased in both groups but there were no significant differences (P = 0.608). The experimental group had a better improvement effect in caries risk assessment items than the control group, including "whether the frequency of eating sugary snacks or drinks between meals is more than 3 times/day" (P = 0.033) and the use of fluoridated toothpaste (P = 0.020). The experimental group was better than the control group in reported oral health behaviors, including frequency of eating sweets before sleep (P = 0.032), brushing time (P = 0.001), and the filled rate (proportion of FS in DMFS) of first permanent molars (P = 0.003). Conclusions: The online caries management platform showed more advantages than traditional lecturing in improving oral health knowledge and behaviors (oral hygiene practice, sugar consumption behavior, and medical treatment behavior). This platform provides a reliable implementation path for the occurrence and continuous improvement of oral health-related behaviors.

[Expression and distribution of transforming growth factor ß3 in the mouse tooth germ during development after advanced bell stage].

OBJECTIVE: To observe the expression and distribution of transforming growth factor ß3 (TGF-ß3) in the mouse tooth germ after advanced bell stage, and to discuss the role of TGF-ß3 during the development of tooth germs. METHODS: BALB/C's mouse tooth germs at 4, 11, and 18 days postnatal (4dpn,11dpn,and 18dpn) were collected and processed for routine fixation, decalcification, embedding, and slicing. The expression of TGF-ß3 was detected by immunohistochemisty. RESULTS: As to 4dpn tooth germ: Positive expression of TGF-ß3 was found in enameloblasts, odontoblasts, ambitus of dental pupilla, with weak positive expression in the intermedial of dental papilla. As to 11dpn tooth germ: Positive expression was seen in enameloblasts, with negative expression in odontoblasts and dental papilla. As to 18dpn tooth, positive expression of TGF-ß3 was showed in the vessel wall and its surrounding, with negative expression in other areas. CONCLUSION: The distribution of TGF-ß3 expression showed a time-space characteristic during the mouse tooth germ development after advanced bell stage, which may exert a regulatory effect on tooth development and this effect is gradually getting weak with the development of tooth germs.

Factors Affecting Future Caries Occurrence Among Preschoolers in Northern Guangdong: A Longitudinal Study.

PURPOSE: This study aimed to investigate the new development of caries among preschoolers in northern Guangdong and to assess caries-related factors to distinguish groups with different caries risk levels. METHODS: Baseline data were recorded for participants from September to November 2019, and participants were reexamined from September to November 2020. A longitudinal observation of 11,973 preschoolers was conducted. The simplified debris index (DI-S) and decayed-missing-filled tooth (dmft) index values were obtained for each participant. RESULTS: Factors associated with whether caries would occur in the future and one-year increase in dmft (Δdmft) included baseline dmft, baseline DI-S, and baseline age. The risk ratio (RR) of caries occurrence and the number of teeth with new-onset caries were 4.482 (95% confidence interval, 4.056-4.957) and 2.945 (2.742-3.165) in the participants with baseline dmft ≥3, which were higher than those with baseline dmft =1 or 2. In the baseline caries-free group, whether caries would occur in the future was related to the baseline DI-S (95% confidence interval, 0.022-0.062). The caries incidence of maxillary central incisors (27.9%) was the highest among teeth of preschoolers without caries at baseline, whereas the caries incidence of mandibular first deciduous molars (42.7%) was the highest among teeth of preschoolers with caries at baseline. CONCLUSION: Baseline dmft is a good predictor of future caries. Children with baseline caries-free status, baseline dmft >0, and baseline dmft ≥3 should be treated with preventive interventions of different intensities and frequencies. The occurrence of future caries in baseline caries-free participants is related to oral hygiene status. Measures to prevent caries on smooth surfaces, such as topical fluoridation, should be applied to all preschoolers. Preschoolers with caries at baseline may be given priority for pit and fissure sealing.

[Dentification ability of inbred strain mice tooth germs homologically transplanted into oral submucosa].

OBJECTIVE: To establish a suitable environment for the bioengineered teeth in vivo by observing the dentification ability of BALB/C mice tooth germs homologically implanted into the oral submucosa. METHODS: The first molar tooth germs of BALB/C mice 4 days after birth were transplanted into the oral submucosa of BALB/C male mice, and then recycled for regular histological observation after 1, 2, 3, and 6 week transplantation. RESULTS: The tooth germs in the oral submucosa grew well with continuing developing enamelum and pulpodentinal complex, and the dentinal tubules were clear. CONCLUSION: The environment of the BALB/C male mice oral submucosa is favorable for the growth of tooth germs in inbred strain BALB/C mice, and it can provide a new environment for the development of bioengineered teeth in vivo.

[Therapeutic effect of the combination of traditional Chinese medicine and western medicine on patients with oral submucous fibrosis].

OBJECTIVE: To observe the therapeutic effect of salvia miltiorrhiza and prednisolone on patients with oral submucous fibrosis (OSF). METHODS: A total of 60 medium-term OSF patients and 60 advanced stage OSF patients were randomly divided into the first group (treated with both salvia miltiorrhiza and prednisolone) and the second group (treated with prednisolone alone). The clinical effect was compared between each group after 3-month treatment. RESULTS: Difference was found in the lesion area of the medium-term cases and the advanced stage cases of the first group before the treatment [(10.37+/-3.40) cm2, (19.60+/-3.27) cm2] and after the treatment [(5.90+/-4.10) cm2, (16.33+/-4.02) cm2] (P<0.05). Significant difference was found in the mouth opening before the treatment [(3.41+/-0.77) cm, (1.98+/-0.39) cm] and after the treatment [(3.87+/-0.67) cm, (2.26+/-0.46) cm] (P<0.05) in the first group. There was significant difference in the lesion area and mouth opening of the medium-term cases of the second group before the treatment [(10.87+/-3.18) cm2, (3.57+/-0.75) cm] and after the treatment [(6.70+/-3.75) cm2, (3.97+/-0.69) cm] (P<0.05). No difference in the lesion area and mouth opening of the advanced stage cases of the second group was found (P>0.05). There was difference in the therapeutic efficacy between the first group (70%) and the second group (16.67%) of the advanced stage cases (P<0.05), but not in the clinical effect between the 2 groups of the medium-term cases (P>0.05). The side effect of prednisolone could be reduced while used together with salvia miltiorrhiza. CONCLUSION: There is obvious advantage in treating OSF by the combination of salvia miltiorrhiza and prednisolone.

Role of autophagy and apoptosis in atrophic epithelium in oral submucous fibrosis.

Oral submucous fibrosis (OSF) is a serious, potentially malignant oral disorder. It is histopathologically characterized by chronic inflammation and atrophic epithelium accompanied by the accumulation of collagen fibers in the lamina propria. The molecular mechanisms leading to atrophic epithelium remain poorly understood. Therefore, the present study investigated the role of autophagy and apoptosis in atrophic epithelium in OSF. The expression of Caspase-3 and autophagy-related proteins (LC3 and P62) in OSF epithelial tissues was quantified by immunohistochemistry. The analysis demonstrated that, compared with normal oral mucosal tissues, autophagy and apoptosis increased with the progression of OSF. Flow cytometry and Western blotting showed that arecoline induces apoptosis in human oral keratinocytes (HOKs) in a time-dependent manner in vitro. Arecoline-induced autophagy was confirmed by transmission electron microscopy and Western blotting. When chloroquine was used as an inhibitor of autophagy, the apoptosis rate and Caspase-3 expression decreased compared with the use of arecoline alone. Thus, autophagy and apoptosis may be involved in atrophic epithelium in OSF, and arecoline-induced autophagy promotes apoptosis in HOKs.

[Epidemiological investigation on deciduous dental caries among children aged 2 approximately 4 years of Kaifu district in Changsha city].

OBJECTIVE: To investigate dental caries of deciduous teeth among preschool children of Kaifu district in Changsha. METHODS: According to the criteria recommended by the Third National Oral Health Investigation, deciduous caries of 459 children aged 2 to 4 were clinically examined. The mean decayed missing filled teeth (dmft) and the prevalence of dental caries for each age group were calculated. The Results were statistically analyzed using SPSS13.0 software package. RESULTS: The prevalence of dental caries was 39.65%.The mean dmft score was 1.32. The prevalence of dental caries and mean dmft increased as children grew up (P<0.05).Dental caries of maxillary deciduous central incisor and mandibular second deciduous molar were significantly more common than other teeth. The filling rate was 7.57%, which increased with age. The prevalence of early childhood caries was 17.21% (17.90% for males and 16.34% for females). CONCLUSION Deciduous dental caries of preschool children are an important problem, and the filling rate is very low. Necessary measures for early prevention of dental caries must be taken.

[Changes of caries activity and calcium, phosphorus concentrations in saliva of patients with nasopharyngeal carcinoma before and after radiotherapy].

OBJECTIVE: To analyze caries activity of nasopharyngeal carcinoma (NPC) patients before and after radiation therapy. The study was also designed to analyze calcium and phosphorus concentrations in saliva of NPC patients before and after radiotherapy. METHODS: Twenty-eight NPC patients and 20 healthy controls were included in this study. Resazurin disc method was used to detect caries activity of NPC patients before and after 70 Gy radiotherapy. The atomic absorption spectrometry and molybdenum-stibium antispetrophotography method were used to analyze calcium and phosphorus concentrations in saliva of NPC patients before and after 70 Gy radiotherapy and the healthy controls. RESULTS: The results of resazurin disc method showed caries activity of NPC patients was increased after radiotherapy (P < 0.01). Calcium concentration in saliva of NPC patients before radiotherapy was (63.19 +/- 3.27) mg x L(-1), phosphorus concentration was (132.96 +/- 5.13) mg x L(-1). After 70 Gy radiotherapy, calcium concentration was (33.38 +/- 0.32) mg x L(-1), phosphorus concentration was (49.18 +/- 2.66) mg x L(-1). The difference of calcium and phosphorus concentrations in saliva before and after radiotherapy was significant (P < 0.01). CONCLUSION: Caries activities of NPC patients increase after radiotherapy. Calcium and phosphorus concentrations in saliva decrease after radiation therapy.

[Effect of mineral trioxide aggregate on proliferation and differentiation of rat dental papilla cells].

OBJECTIVE: To investigate the effects of mineral trioxide aggregate(MTA) on the proliferation and differentiation of rat dental papilla cells(RDPC). METHODS: RDPC were cultured by tissue block method and identified.RDPC of the third passage were cultured with material extract fluid containing different mass concentrations of MTA (0.002, 0.02,0.2, 2 and 20 g/L) for 3 d, those cultured with routine culture fluid served as control group. The proliferation-related parameters were measured by methyl thiazolyl tetrazolium(MTT) assay. RDPC were cultured with material extract fluids containing 0.002 g/L MTA, those cultured with routine culture fluid served as control group, the activity of alkaline phosphatase(ALP) at 1, 3,5, 7 d and the level of collagen I at 1, 3,5 d were detected. RESULTS: MTT results showed that the A value of RDPC of group 20 g/L (0.092 ± 0.011) was less than that of the control group (0.249 ± 0.006) at 3 d(P < 0.01), the A value of RDPC of group 0.02 g/L (0.267 ± 0.005) and 0.002 g/L (0.276 ± 0.006) were more than that of the control group (0.249 ± 0.006) at 3 d(P < 0.01). ALP detection proved that ALP activity of MTA at 3 d (0.217 ± 0.008), 5 d (0.253 ± 0.005) , 7 d (0.279 ± 0.004) were more than that of the control group at 3 d (0.166 ± 0.006) ,5 d (0.221 ± 0.006), 7 d (0.242 ± 0.004) (P < 0.01). Collagen I detection showed that the level of collagen I of MTA at 3 d[(78.46 ± 2.72) µg/L], 5 d[(90.73 ± 3.08) µg/L] were more than that of the control group at 3 d[ (66.75 ± 3.08) µg/L], [5 d (74.27 ± 3.50) µg/L] (P < 0.01). CONCLUSIONS: MTA of high concentrations can significantly inhibit cell growth, and of low concentrations can promote cells proliferation and differentiation.

The effects of different Er: YAG laser parameters combined with dole fluorine on dentinal tubules / 口腔疾病防治

Objective@# To explore the effects of Er: YAG lasers with different pulse energies and of Er: YAG lasers combined with Duraphat on dentine surface morphology and the dentinal tubule exposure rate, thereby providing a theoretical basis and parameters for clinically treating dentine hypersensitivity with Er: YAG lasers.@*Methods @# Dentinal tubule exposure models were divided into five groups, namely, group A (single Er: YAG laser exposure), group B (Duraphat+ Er: YAG laser), and group C (Er: YAG laser+Duraphat), which were exposed to 6 levels of pulse energy (80 mJ/P- 250 mJ/P), and experimental control group D (Duraphat group) and blank control group E. Scanning electron microscopy was used to observe dentine surface morphology and dentinal tubule closure in these groups, and Image-Pro Plus 6.0 software was used for image analysis to measure the exposure rates of the five groups of dentinal tubules.@*Results@#The dentinal tubule exposure rates for the A-D groups were significantly lower than that of the E group (P < 0.001); when the Er: YAG laser pulse energy was less than 250 mJ/P, the dentinal tubule exposure rates for the A-C groups were all lower than that of the D group, but when the pulse energy was higher than 250 mJ/P, the dentinal tubule exposure rates for the A-C groups were higher than that of the D group, showing significant differences (P < 0.001); under the same handling method, when the pulse energy was 80~200 mJ/P, the dentinal tubule exposure rate decreased as the pulse energy increased. If the pulse energy reached 250 mJ/P, the exposure rate of the dentinal tubules increased instead. There were apparently no significant differences between 80 mJ/P, 100 mJ/P, 160 mJ/P and 200 mJ/P in the A and C groups or between 80 mJ/P and 100 mJ/P in the B group (P > 0.05), while significant differences existed among the other groups (P< 0.05). Under the same pulse energy, the dentinal tubule exposure rates were A group > C group >B group; under different pulse energies, there existed significant differences between the A and B groups (P < 0.05); when the pulse energy was 120~250 mJ/P, there were significant differences between the B and C groups (P < 0.05), while there were no significant differences among other groups (P＜0.05).@*Conclusion@#Er: YAG lasers can close the dentinal tubules and play a cooperative role if combined with Duraphat; the effects of laser exposure are better if fluorine is applied beforehand; and dentinal tubule closure is positively correlated with the pulse energy of Er: YAG lasers within a certain energy scope, but when the pulse energy reaches 200 mJ/P, the dentine surface is excessively fused and injured.

[Exploring the relationship between secreted frizzled-related protein 1 and chronic periodontitis].

OBJECTIVE: This study detects the expression of secreted frizzled-related protein 1 (SFRP1) in healthy patients and patients with chronic periodontitis (CP) and explores the relationship between SFRP1 and the occurrence and development of CP. METHODS: First, 28 patients forming the CP group were further divided into mild, moderate, and severe CP subgroups according to clinical attachment loss (CAL) data. Ten healthy volunteers were recruited in the control group. Gingival crevicular fluid (GCF) was collected from all of the patients, and the concentration of SFRP1 in the GCF samples was detected using enzyme-linked immunosorbent assay. Next, gingival lesions were obtained from 22 patients in the CP group and healthy gingival tissues were obtained from the 10 healthy patients in the control group. Immunohistochemical analysis for SFRP1 was used to analyze the correlation between the expression of SFRP1 and the severity of CP based on staining intensities. RESULTS: The concentration of SFRP1 in GCF samples taken from of the CP group (281.07 ng x L(-1) +/- 33.37 ng x L(-1)) was significantly higher than that in samples taken from the control group (245.30 ng x L(-1) +/- 35.69 ng x L(-1)) (P < 0.05). A significant positive correlation was observed between the concentration of SFRP1 in GCF and CAL (r = 0.651, P < 0.001). Furthermore, the SFRP1 scores in the CP groups (4.500 +/- 0.913) were significantly higher than those in the control group (2.800 +/- 1.135) (P < 0.001). SFRP1 scores did not vary significantly among the CP subgroups (P > 0.05). CONCLUSION: SFRP1 expression in the CP groups was significantly higher than that in the control group. Thus, SFRP1 may play a significant role in the development of CP.