Outcome of regenerative endodontic procedures in delayed replanted immature permanent teeth with apical periodontitis: A retrospective study.

BACKGROUND: Regenerative endodontic procedures (REPs) is effective for treating young permanent teeth with pulp necrosis. However, its efficacy on delayed replanted avulsed teeth is unclear. AIM: This retrospective study aimed to assess the efficacy of REPs in treating delayed replanted immature permanent teeth with apical periodontitis. DESIGN: Avulsed teeth receiving REPs were systematically screened based on predetermined criteria. This study assessed the REP outcomes, postoperative periodontal healing, and overall treatment efficacy. Samples were grouped by REP outcomes and root development stage, with Fisher's exact tests used to compare outcomes among different groups. RESULTS: Among the included 17 teeth, 47.1% exhibited successful REPs and periodontal healing. Another 47.1%, due to replacement resorption or REP failure, were categorized as tooth survival. Healing of periapical lesions was observed in 88.2% of the cases, but only 41.2% demonstrated continued root development. Although differences were not significant (p = 0.05), teeth with continued root development had a higher rate of functional healing (85.7%) compared to those without (30%). CONCLUSION: Within the limitations of this study, REPs presented reliable outcomes for treating delayed replanted immature permanent teeth with apical periodontitis mainly in periapical lesion healing. Teeth with continued root development after REPs exhibited a higher rate of functional healing. Further investigation is required to explore potential synergies between REP outcomes and periodontal healing.

Use of the Hall Technique by dentists in East China: A questionnaire-based cross-sectional survey.

BACKGROUND: The Hall Technique (HT) is now regarded as one of the biological management options for carious primary molars and has shown significant clinical success. AIM: To investigate the perception and the use of the HT among dentists engaging in paediatric dentistry in East China. DESIGN: This was an electronic questionnaire-based cross-sectional study. A quick response code of the questionnaire via WeChat, a common communication tool in China, was sent to dentists in East China. RESULTS: A total of 313 dentists participated in this study. Most surveyed clinicians had heard about the HT (n = 286, 91.4%). Of them, 40.2% (n = 115) reported having used the HT. Of 67 dentists working in private clinics, 34 (50.7%) had used the HT, whereas only 37% of dentists from public hospitals had used the HT. Of 115 dentists having used the HT, 91.3% (n = 105) would consider using the HT for Class II cavitated molars; 23.5% (n = 27) would consider using the HT for Class I cavitated molars. Most dentists who had not used the HT were concerned about complications such as pulp inflammation or necrosis after applying the HT. CONCLUSION: The HT is well known in East China; the lack of systematic training or courses, however, may decrease its utilization.

Oral health-related quality of life and associated factors among a sample from East China with severe early childhood caries: a cross-sectional study.

BACKGROUND: To investigate the oral health-related quality of life (OHRQoL) and associated factors among a sample from East China with severe early childhood caries (S-ECC). METHODS: A total of 316 children with S-ECC and their parents were recruited to participate in a cross-sectional study. Children were examined for caries status using criteria proposed by World Health Organization (WHO). The accompanying parent was required to provide demographic information and complete two validated questionnaires in Chinese: the early childhood oral health impact scale (ECOHIS) and the 5-item oral health impact profile (OHIP). RESULTS: The study had a 98.1% response rate. Finally, the data of 300 children and their parents were analyzed. Mothers cared for their children far more than fathers in the included family (78.7% mother, 21.3% father). The mean age of children was 4.1 ± 0.7 years, ranging from 3 to 5. The mean dmft score was 13.8 ± 3.8. Few (13.7%) children never had a toothache. ECOHIS scores ranged from 0 to 38, with a mean score of 16.2 ± 7.2. The mean OHIP score was 2.9 ± 2.7. The parental age, family income, residence, history of pain, the dmft scores and parents' OHIP showed associations with ECOHIS scores or domain scores (P < 0.05). The multiple regression analysis showed that the history of pain, accompanying parents' OHIP, and the dmft scores were mainly associated with ECOHIS and child impact (P < 0.05); parental age was associated with family impact (P = 0.024). CONCLUSIONS: The parent's OHRQoL was associated with the children's OHRQoL, indicating that policymakers and clinical practitioners should improve both children's and their parents' oral health. Furthermore, the caries severity and the history of dental pain impacted children's OHRQoL.

Clinical outcomes of dental treatment under general anesthesia and its effects on the caries activity and body growth of children: a 2-year retrospective study.

OBJECTIVES: To analyze clinical outcomes of dental treatment under general anesthesia (DGA) and its effects on children's caries activity status and body growth within 2 years after the treatment. MATERIALS AND METHODS: The case data and 2-year follow-up records of children who underwent DGA from February 2017 to February 2018 were collected and analyzed. The general characteristics of the sample, the success rates of treatment procedures, the caries recurrence rate, the caries activity test scores, and the BMI of all the children were described. The caries activity levels between children with and without caries recurrence at 24 months after DGA were compared before and after DGA to explore the relationship between caries activity level and caries recurrence. The correlation between BMI level and caries recurrence was explored using Cox regression analysis. RESULTS: A total of 94 children consisting of 46 boys and 48 girls were included in this study. The average dmft score before DGA was 13.90. Within 2 years after the treatment, composite fillings and strip crowns of the anterior teeth achieved similar success rates, around 90%; SSCs showed a similar success rate to composite fillings of posterior teeth (P = 1.000); the clinical success rate of pulpectomy was 90.43%. All the children showed no caries relapse at 1 month after DGA. The number of children with caries relapse at 6-, 12-, and 24-month post-treatment was 24 (25.53%), 35 (37.23%), and 53 (56.38%), respectively. The caries activity scores at each follow-up were significantly lower than those before the treatment (P < 0.0001). Children with caries relapse within 2 years after DGA showed no significantly different caries activity scores than children without caries relapse before and after the treatment. The proportion of children with normal BMI at 12 months after DGA was significantly higher than that before DGA (P = 0.007), and the difference was still very significant at 24 months after DGA (P < 0.0001). Statistical results showed a correlation between BMI level before DGA and caries recurrence (P < 0.001). CONCLUSIONS: Dental treatment under general anesthesia achieves acceptable clinical outcomes in this study. Children's caries activity scores decrease significantly. Low or high BMI levels before DGA drift towards normal after the treatment. CLINICAL RELEVANCE: Acceptable outcomes are achieved within 2 years after dental treatment under general anesthesia. However, children with abnormal BMI before the treatment tend to have caries relapse.

Effect of orofacial myofunctional therapy along with preformed appliances on patients with mixed dentition and lip incompetence.

BACKGROUND: Various preformed early orthodontic appliances for correcting oral habits and training orofacial muscles have emerged on the market. However, there are few reports on the effectiveness of these appliances for orofacial myofunctional training. METHODS: This retrospective study evaluated children with lip incompetence and mixed dentition treated at the Pediatric Dentistry Department of Shanghai Ninth People's Hospital from 2016 to 2018. A total of 109 children (54 males, 55 females; age range: 7-10 years, mean age: 8.2 years) were selected from an overall sample of 870 patients. During the first visit, all patients were instructed to perform active lip and tongue training at home daily and were divided into two groups according to the kind of appliances worn. The first group consisted of 56 subjects (30 females; 26 males), with a mean age of 8.1 years (SD 1.1 years), treated with preformed appliances. The second group consisted of 53 subjects (25 females; 28 males), with a mean age of 8.2 years (SD 1.0 years), treated with conventional early orthodontic appliances (arch expansion devices along with "2*4" local fixed appliances). For each subject in the two groups, initial (pretreatment, T1) and final (posttreatment, T2) intraoral and external photos, dental casts, lateral cephalograms, and orthopantograms were taken, and lip strength was measured. SNA, SNB, ANB, APDI, FMA, U1SN, and IMPA before and after treatment were measured by The Dolphin Imaging Cephalometric Analysis Software. The hyoid bone position was also recorded. Differences between groups were identified with an independent sample t-test (P < 0.05). RESULTS: In the first group, a statistically significant forward movement of the mandible was detected by an increase in SNB of - 1.06 degrees (P < 0.01) and an increase in APDI of - 2.23 degrees (P < 0.01). The increase in IMPA (- 3.21 degrees, P < 0.01) demonstrated a statistically significant protrusion of the lower incisors. Lip strength significantly increased (- 2.44, P < 0.01). The increase in HC3 (- 1 mm, P < 0.01) and HFH (- 2.95 mm, P < 0.01) implied a forward and downward movement of the hyoid bone. In the second group, a statistically significant forward movement of the mandible was also detected by an increase in APDI of -1.96 degrees (P < 0.01). Lip strength also significantly increased (- 1.24, P < 0.01). The increase in HFH (- 2.55 mm, P < 0.01) implied a downward movement of the hyoid bone. Compared with the treatment in the second group, orofacial myofunctional therapy combined with the preformed appliances led to a statistically significant lip strength increase (- 2.30, P < 0.05). Significant differences were observed in SNB and IMPA between the two groups (P < 0.05). CONCLUSIONS: Orofacial myofunctional therapy effectively improved patient lip strength and was a good option for mixed dentition patients with lip incompetence. Preformed appliances could enhance the orofacial myofunctional therapy effect and result in significant improvements in lip strength and forward movement of the mandible, which can optimize the jaw relationship.

Dental maturation in a Chinese sample using Demirjian method.

BACKGROUND: Dental calcification information is relevant for clinical, archaeological, and forensic applications. However, dental maturity measurements in current cohorts of Chinese children are insufficient. AIM: This study aimed to establish the mandibular dental maturity table and determine the accuracy of dental age estimation using the Demirjian method in a Chinese sample. SUBJECTS AND METHODS: Permanent mandibular teeth, excluding the third molar, in 2091 panoramic radiographs of 1008 males and 1083 females aged 3-15 were graded, and dental age was estimated according to Demirjian's criteria. Age-of-attainment was calculated with probit regression for each stage by sex, and sex differences were analysed using the Mann-Whitney U test. Dental age was compared with chronological age using paired t-tests. RESULTS: Although females showed earlier age-of-attainment than males, significant sex differences were only found in stages D-G (p < 0.05). The Demirjian method overestimated the dental age in both males (0.68 ± 1.05 years) and females (0.59 ± 0.97 years). CONCLUSIONS: The relationship between mineralisation stage and chronological age in this study can be applied as a reference for mandibular dental maturity of Chinese children and adolescents. The Demirjian method overestimated the chronological ages of this sample.

Effects of occlusal cavity configuration on 3D shrinkage vectors in a flowable composite.

OBJECTIVE: The objective of this study was to investigate the effects of cavity configuration on the shrinkage vectors of a flowable resin-based composite (RBC) placed in occlusal cavities. MATERIALS AND METHODS: Twenty-seven human molars were divided into three groups (n = 9) according to cavity configuration: "adhesive," "diverging," and "cylindrical." The "adhesive" cavity represented beveled enamel margins and occlusally converging walls, the "diverging" cavity had occlusally diverging walls, and the "cylindrical" cavity had parallel walls (diameter = 6 mm); all cavities were 3 mm deep. Each prepared cavity was treated with a self-etch adhesive (Adper Easy Bond, 3 M ESPE) and filled with a flowable RBC (Tetric EvoFlow, Ivoclar Vivadent) to which had been added 2 wt% traceable glass beads. Two micro-CT scans were performed on each sample (uncured and cured). The scans were then subjected to medical image registration for shrinkage vector calculation. Shrinkage vectors were evaluated three-dimensionally (3D) and in the axial direction. RESULTS: The "adhesive" group had the greatest mean 3D shrinkage vector lengths and upward movement (31.1 ± 10.9 µm; - 13.7 ± 12.1 µm), followed by the "diverging" (27.4 ± 12.1 µm; - 5.7 ± 17.2 µm) and "cylindrical" groups (23.3 ± 11.1 µm; - 3.7 ± 13.6 µm); all groups differed significantly (p < 0.001 for each comparison, one-way ANOVA, Tamhane's T2). CONCLUSION: The values and direction of the shrinkage vectors as well as interfacial debonding varied according to the cavity configuration. CLINICAL RELEVANCE: Cavity configuration in terms of wall orientation and beveling of enamel margin influences the shrinkage pattern of composites.

Surface properties and color stability of incrementally-filled and bulk-fill composites after in vitro toothbrushing.

PURPOSE: To evaluate the effect of simulated toothbrush abrasion on the surface gloss, the surface roughness and the color stability of incrementally-filled and bulk-fill composites. METHODS: 48 dimensionally standardized composite specimens (n= 8/group) were made from four incrementally-filled composites (Tetric EvoCeram, IPS Empress Direct Enamel, Ceram X mono and Arabesk) and two bulk-fill composites (Quix fil and Tetric EvoCeram Bulk). Before and after toothbrushing simulation the surface gloss was measured by a glossmeter, the surface roughness was evaluated with a profilometer, and the color was measured using a spectrophotometer. RESULTS: Before and after the toothbrush abrasion, IPS Empress Direct Enamel yielded the highest gloss value, while Ceram X mono exhibited the lowest gloss value. Quix fil showed the highest Ra value before the toothbrushing simulation, however, it showed similar Ra value with Ceram X mono and Arabesk after the toothbrushing simulation. IPS Empress Direct Enamel showed the lowest ΔE after the simulated toothbrushing. Tetric EvoCeram Bulk showed similar gloss value, Ra value, and ΔE to Tetric EvoCeram after the toothbrushing simulation. Simple regression analysis showed no correlation between the roughness and the gloss, but it showed a positive linear relationship between ΔE and ΔRa. (R2= 0.863, P= 0.027). CLINICAL SIGNIFICANCE: The evaluated bulk-fill composites did not exhibit significantly worse surface properties and color stability than incrementally-filled materials after toothbrush abrasion. Color changes of composites caused by toothbrush abrasion were acceptable on the premise that 3.3ΔE units were considered as acceptable threshold values.

Shear bond strength of two adhesives to bovine dentin contaminated with various astringents.

PURPOSE: To investigate the in vitro shear bond strength of two adhesives to bovine dentin contaminated with various astringents. METHODS: 120 adult bovine incisors were collected and cut to obtain 240 specimens. The specimens were randomly divided into a self-etch adhesive group (N = 120) and a total-etch adhesive group (N = 120). Both of the groups were divided into the following six subgroups: the non-contamination group and the contamination groups 25% Al2(SO4)3 (Orbat sensitive), 25% AlCl3 (Racestyptine), 10% AlCl3 (Roeko Gingiva Liquid), 15.5% Fe2(SO4)3 (Astringedent) and AlCl3 Paste (Astringent Retraction Paste, N = 20 in each subgroup). Each astringent was applied for 1 minute to the dentin surface before rinsing with water spray for 20 seconds. The respective adhesive was then applied according to the manufacturer's instructions. Two composite cylinders were shaped with a mold, cured on the dentin surface of each specimen and sheared off after 1 day and 1 week storage. The shear bond strengths (MPa) were recorded and analyzed with ANOVA. Results: In the self-etching adhesive group, all astringents showed negative effects on dentin bonding (P < 0.05). Astringent contamination did not have a negative effect on dentin bonding in the total-etch adhesive group (P > 0.05).

An in vitro comparison of fluorescence-aided caries excavation and conventional excavation by microhardness testing.

OBJECTIVE: The aim of this in vitro study was to compare fluorescence-aided caries excavation with conventional excavation based on the Martens and Vickers hardness of dentin at the cavity floor after caries removal. MATERIALS AND METHODS: In total, 20 extracted human teeth with dentin caries were bisected through the lesion center into two halves, which were assigned to either the fluorescence-aided caries excavation group or the conventional excavation group. After the treatment, embedding, mounting, and polishing, a line of indentations from the dental pulp across the sound dentin to the cavity floor was made on each sample. The data were compared with Student's t and Mann-Whitney U tests. RESULTS: The calculated Vickers hardness of the sound dentin was 57 ± 10 kg/mm(2) in the fluorescence-aided caries excavation group and 59 ± 8 kg/mm(2) in the conventional excavation group, which is consistent with the previous studies. The absolute and relative Martens hardness measurements of the cavity floor were 224 ± 93 N/mm(2) and 46 ± 17%, respectively, in the fluorescence-aided caries excavation group and 412 ± 75 N/mm(2) and 81 ± 14%, respectively, in the conventional excavation group. Based on either the Martens or Vickers hardness, both the absolute and relative microhardness measurements of the cavity floor after fluorescence-aided caries excavation were significantly lower than the values obtained by conventional excavation. CONCLUSION: Fluorescence-aided caries excavation showed the tissue-preserving property and was more conservative than the conventional excavation in this in vitro study.

MicroCT-based comparison between fluorescence-aided caries excavation and conventional excavation.

PURPOSE: To evaluate and compare the use of micro-computed tomography (microCT) to investigate the mineral concentration of the treated dentin surface after caries removal with fluorescence-aided caries excavation (FACE) and conventional excavation. METHODS: 20 extracted human teeth with dentin caries were bisected through the lesion center into two halves which were distributed to a FACE and a conventional excavation group. Tungsten-carbide round burs were used for both groups. Each specimen was investigated with microCT after excavation. The obtained images of all the specimens were evaluated using Image J. Based on the grey values, the linear attenuation coefficients were calculated. Four resin-embedded solid hydroxyapatite phantoms with the gradually increased mineral concentration were used to obtain a calibration curve and equation. Finally, the mineral concentration values of the superficial dentin of each specimen after removal and sound dentin were calculated. The data were compared with the Student's t-test. RESULTS: The statistical results showed that the linear attenuation coefficient (LAC) of the treated surface was significantly lower (P < 0.0001) in the FACE group with a mean value of 2.13 +/- 0.33 cm9-1). The value of the conventional excavation group was 2.98 +/- 0.19 cm(-1). The LAC of sound dentin was 3.89 +/- 0.10 cm(-1). By using the calibration equation, the calculated mineral concentration of the superficial dentin after caries removal were 0.68 +/- 0.14 g/cm3 in the FACE group and 1.05 +/- 0.08 g/cm3 in the conventional excavation group. The mineral concentration of sound dentin was 1.44 +/- 0.04 g/cm3. The mineral concentration of the superficial dentin after caries removal in the FACE group was about 47% of that of sound dentin, while the value in the conventional excavation group was approximately 73% of that of sound dentin. Under the conditions of this in vitro study, the results of the microCT evaluation may imply that FACE was more conservative than conventional excavation.

Efficacy of tooth whitening with different calcium phosphate-based formulations.

The aim of this in-vitro study was to evaluate the efficacy of tooth whitening using different calcium phosphate-based formulations. Teeth were treated with three different hydroxyapatite preparations at different concentrations and with two control preparations; each tooth was treated a total of three times. After application of the last material, hydrodynamic shear force was applied to mimic mechanical loading. After each treatment, tooth color was measured using a dental spectrophotometer, and the mean changes in L*a*b* values between different measurements were expressed as ∆E. The results indicated significant differences between the materials, but neither dose- nor time-dependent associations were found. The suspension containing tricalcium phosphate (10 wt%) showed the most obvious color change (∆E = 2.20 ± 0.90), while the suspension containing zinc-carbonate-apatite (20 wt%) showed the least obvious color change (∆E = 0.91 ± 0.50). Calcium phosphate-based formulations that can adhere to the enamel surface and contribute to tooth whitening have promising tooth-whitening potential.

An in vitro study on the secondary caries-prevention properties of three restorative materials.

STATEMENT OF PROBLEM: Secondary caries is considered to be the most important and common reason for the replacement of all types of restorations. PURPOSE: The purpose of the study was to evaluate in vitro both the anticaries efficacy and marginal integrity of amalgam, glass ionomer cement, and composite resin restorations in a cariogenic condition. MATERIAL AND METHODS: Class II cavities were prepared on 60 extracted teeth, which were assigned to 3 groups and restored either with amalgam, glass ionomer, or composite resin. After thermal cycling and sterilization, the teeth were set in an artificial carious environment for 10 days. The bacteria from the margin of the restorations were then collected, and microleakage was evaluated by means of dyeing. According to the locations, the demineralization of tooth tissue around the restoration was divided into 3 parts: artificial outer lesion, artificial enamel wall lesion, and artificial dentin wall lesion. The depths of the artificial outer lesion and the areas of the artificial enamel and dentin wall lesions were investigated with a confocal laser scanning microscope after all the specimens had been stained with 0.1 mM Rhodamine B. Statistical analyses consisted of 1-way ANOVA and Kruskal-Wallis tests (α=.05). RESULTS: No significant difference was noted in terms of the number of bacteria around the restorations for the 3 materials; the microleakage of amalgam was the least among the 3 types of restorations; the outer enamel lesion depth around the glass ionomer cement was the lowest, and the wall lesion area around the amalgam was the smallest. CONCLUSIONS: No definite inhibitory effect of fluoride releasing restorative materials (glass ionomer) was apparent on Lactobacillus acidophilus in this study. The amalgam restorations showed the best marginal integrity and the smallest artificial wall lesion among the 3 types of restorations.

Early childhood caries prevalence and associated factors among preschoolers aged 3-5 years in Xiangyun, China: A cross-sectional study.

Purpose: This study aimed to investigate the early childhood caries (ECC) prevalence among preschoolers aged 3-5 years in Xiangyun of Yunnan, China and explore the factors associated with the prevalence. Materials and methods: A cross-sectional survey including 3-5-year-old children was conducted in Xiangyun County, China, between September and November 2020. According to the dental examination standard of the WHO 2013 criteria, the presence of ECC was recorded. Besides the dental examination for children, their parents completed questionnaires about caries-related factors, including demographic variables, family socioeconomic status, feeding, and oral health-related habits, parental dental knowledge, and the condition of dental service utilization. SPSS Statistics 25.0 (IBM, Chicago, IL, USA) was used for data analysis. Statistical significance was set at p < 0.05. Results: The ECC prevalence among a sample of 1,280 children aged 3-5 years consisting of 665 boys and 615 girls in this study, was 74.3%, and the mean decayed-missing-filled teeth (dmft) was 4.9 ± 5.0. There were no statistically significant differences in the ECC prevalence between the sexes and among different ethnic groups. Children with different dietary and oral hygiene habits showed no significantly different prevalence of ECC. Logistic regression analysis showed that the most significantly associated factors were older age, lower family income, and worse parental perception of children's oral health status. Conclusion: The ECC prevalence among 3-5-year-old preschool children in Xiangyun was higher than the average national ECC prevalence in China. This study implies that more attention should be given to children's caries prevention from early childhood; oral health education and promotion should be intensified to reduce the ECC prevalence and improve the oral health status of children in Xiangyun.

Caries prevalence of the first permanent molar and associated factors among second-grade students in Xiangyun of Yunnan, China: A cross-sectional study.

Purpose: This study aimed to explore the caries prevalence of the first permanent molar (FPM) and the associated factors among second-grade students in Xiangyun of Yunnan, China. Materials and methods: A cross-sectional survey was conducted in Xiangcheng Town, Xiangyun County, China, from September to November 2020. The methodology recommended by WHO was used for the dental examination. All the parents were required to complete a questionnaire to collect information on children's family background, dietary habits, oral health behaviors and parental oral health-related knowledge. The tests of significance used were the chi-square test. The association between dental caries prevalence and its associated factors was investigated using logistic regression analysis. Statistical significance was set at P < 0.05. Results: Data of 1,295 second graders consisting of 665 males and 630 females were analyzed. The caries prevalence of FPM was 47.6%, and the mean DMFT was 1.11 ± 1.394 in this sample. Among all the children with caries, the filling rate is meager, 2.6%. There were statistically significant differences in the caries prevalence of FPM among age groups. No significant difference existed between the sexes. Logistic regression analysis showed that the most significantly associated factors were: consuming desserts at least once a day, no fluoride varnish application experience, worse parental perception of children's oral health status, and incorrect parental knowledge of whether decayed primary teeth need treatment. Conclusion: Caries prevalence of FPM among second-grade schoolchildren in Xiangyun was considerably higher than the average prevalence nationwide in China. As China aims to reduce dental caries to <25% of 12-year-old children in 2030, the local government of remote regions like Xiangyun needs to do much more to achieve this goal. Results of this study could provide a framework for ongoing and future public oral health programs and policy planning in Xiangyun, with particular attention to early preventive and therapeutic measures.

[A survey of parents' cognition about orofacial myofunctional therapy in children with orofacial muscle dysfunction].

PURPOSE: To investigate the difference of parent's cognition of children's orofacial myofunctional therapy (OMT) and its influencing factors, to provide reference for children's OMT. METHODS: Self-designed questionnaire was used to investigate the basic information and related problems of 98 parents whose children received OMT. SPSS 22.0 software package was used for statistical analysis. RESULTS: The parents' total cognition of OMT was relatively low (23.47%). The cognition of malocclusion (68.4%) was significantly different from that of orofacial dysfunction (26.5%), the therapeutic significance of OMT (28.6%) and the attitude of specific treatment of orofacial myofunctional therapy (23.5%) (P<0.001). Parents with different backgrounds had different recognition of OMT: the cognitive degree of parents over 50 years old was low(13.33%), while the cognitive degree of the parents with high educational background was high (48.08%). There was no significant difference in cognition among different gender, occupation and family monthly income. High recognition had good compliance and cooperation. Comparing with low recognition, the difference from high recognition on compliance and cooperation was significant(P<0.01). CONCLUSIONS: OMT is a long-term treatment process, which needs children's perseverance and active cooperation. The curative effect mainly depends on the children's compliance and cooperation. Higher awareness is the premise of good compliance and cooperation. To improve the recognition of OMT and avoid occurrence of malocclusion, it is necessary to strengthen education of OMT, especially for parents with special backgrounds.

[Short-term prognosis of laterally luxated primary teeth left without treatment: a retrospective study of 45 consecutive cases].

PURPOSE: To study the clinical prognosis of laterally luxated primary teeth after 6-month follow-up without treatment. METHODS: Patients with laterally luxated primary teeth, visiting Department of Pediatric Dentistry, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine from March 2018 to March 2019, were selected for the study. Based on the inclusion and exclusion criteria, totally 45 patients with 57 primary teeth were included. The reposition outcomes and pulp prognosis were reviewed at the end of follow-up. The data were analyzed using SPSS 23.0 software package. RESULTS: During a 6-month follow-up, 92.98% of the luxated teeth showed spontaneous reposition while only 31.58% of the traumatic teeth were back to the original position. Regarding the pulp healing complications, 54.39% of the luxated teeth exhibited no clinical symptoms, and 14.04% of the evaluated teeth displayed pulp canal obliteration, and pulp necrosis happened in 31.58% of the injured teeth. There was significant difference in the reposition outcome between labial-palatal luxation and mesial-distal luxation(P<0.05), but no significant difference was found in pulp prognosis between the two luxation types(P>0.05). Spontaneous reposition and crown discoloration observed in most of the evaluated cases, were the earliest signs after one-month follow-up. Periapical translucent image and root resorption due to periapical inflammation showed within the first three months after injury, pulp canal obliteration appeared after 6 months. CONCLUSIONS: In general, most of the laterally luxated teeth left without treatment can reposition spontaneously and show lower incidence of pulp necrosis compared with mature permanent teeth in half a year after injury. The direction of luxation does not affect pulp prognosis but has an influence on teeth reposition procedure.

The microfloral analysis of secondary caries biofilm around Class I and Class II composite and amalgam fillings.

BACKGROUND: Secondary caries is responsible for 60 percent of all replacement restorations in the typical dental practice. The diversity of the bacterial sources and the different types of filling materials could play a role in secondary caries. The aim of this study was to determine and compare the microbial spectrum of secondary caries biofilms around amalgam and composite resin restorations. METHODS: Clinical samples were collected from freshly extracted teeth diagnosed with clinical secondary caries. Samples were categorized into four groups according to the types of restoration materials and the classification of the cavity. Biofilms were harvested from the tooth-restoration interface using a dental explorer and after dilution were incubated on special agars. The bacteria were identified using the biochemical appraisal system. Statistical calculations were carried out using SPSS11.5 software to analyze the prevalence of the bacteria involved in secondary caries. RESULTS: Samples from a total of four groups were collected: two groups were collected from amalgam restorations, each had 21 samples from both Class I and Class II caries; and the other two groups were from composite resin restorations, each had 13 samples from both class I and class II caries. Our results showed: (1) Anaerobic species were dominant in both restoration materials. (2) In terms of the types of individual bacteria, no significant differences were found among the four groups according to the geometric mean of the detected bacteria (P > 0.05). However, there were significant differences among the detected bacteria within each group (P < 0.05). The composition of each bacterium had no statistical difference among the four groups (P > 0.05), but showed significant differences among the detected bacteria in each group (P < 0.05). (3) Among the four groups, there were no significant differences for the detection rate of each bacterium (P > 0.05), however, the detection rate of each bacterium within each group was statistically different among the detected bacteria (P < 0.05). CONCLUSIONS: The proportion of obligatory anaerobic species was much greater than the facultative anaerobic species in the biofilm of secondary caries. Statistically, the materials of restoration and the location of secondary caries did not show any significant effects on the composition of the microflora.

Roles of heterogeneous nuclear ribonucleoprotein L in enamel organ development and the differentiation of ameloblasts.

OBJECTIVE: We aimed to explore the role of Heterogeneous Nuclear Ribonucleoprotein L(hnRNP L) in enamel organ development through hnRNP L conditional knockout mice and knockdown of hnRNP L expression in mouse ameloblast-lineage cells (mALCs) METHODS: We created K14cre-mediated hnRNP L conditional knockout mice (hnRNP LK14/fl) and silenced the expression of hnRNP L in mALCs to investigate the role of hnRNP L in enamel organ development. RESULTS: We found that hnRNP LK14/fl mice presented enamel organ development defects with reduced number of inner enamel epithelium (IEE) cells. The proliferation and differentiation of the IEE cells/ameloblasts were suppressed. The cell proliferation and mineralization ability were also decreased after hnRNP L knockdown. Further studies showed that Bone Morphogenetic Protein (BMP) signaling pathway was attenuated after the knockdown of hnRNP L expression both in vivo and in vitro. CONCLUSIONS: These findings suggest that hnRNP L plays a critical role in enamel organ development by promoting the IEE cell/ameloblast proliferation and differentiation. BMP signaling pathway may be involved in the process.

[Radiographic study of the age for crown and root length completion stages of permanent teeth in male and female children].

PURPOSE: To determine the age medians for crown and root length completion stages of permanent teeth (except for the third molars) and to study gender differences in crown and root length completion stages by radiographic examinations. METHODS: The development of permanent teeth (except for the third molars) was evaluated from 3304 panoramic radiographs of children aged between 3 and 18 years by Haavikko's method. Statistical analysis was performed using SPSS 25.0 software package. Age medians for crown and root length completion stages of permanent teeth were calculated. Gender differences were analyzed by Mann-Whitney U test. RESULTS: There were no significant gender differences in crown completion stages of central incisor and first molar, of which P values were 0.143 (for maxillary central incisor), 0.122 (for maxillary first molar), 0.191 (for mandibular central incisor) and 0.558 (for mandibular first molar), while girls were found to be ahead of boys for crown completion stages of other teeth. In maxilla, girls were found to be ahead of boys for root length completion stages except for lateral incisor, second premolar and second molar, of which P values were 0.057, 0.130 and 0.294; in mandible, except for second premolar and second molar, girls were observed to be ahead of boys for root length completion stages, of which P values were 0.428 and 0.057. CONCLUSIONS: It is concluded that girls are advanced than boys for crown and root length completion stages in most teeth. There is a similarity in gender differences for crown and root length completion stages between maxilla and mandible.