[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.

[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.

[Effect of caries treatment under general anesthesia on oral health behavior and growth development of children in short term].

PURPOSE: To study changes of children caries activity after treatment under general anesthesia, and to analyze effect of caries treatment under general anesthesia on oral health behavior and growth index of children. METHODS: Patients who met criteria and were treated under general anesthesia were included in this study. Informed consent for this study was obtained from parents. Before and after treatment, children's oral health conditions were examined; height, weight were recorded; the caries activity was evaluated. In addition, questionnaires related to oral health behavior and early childhood oral health impact scales were fulfilled by parents. The patients were followed for 6 months after treatment. The data were analyzed using SPSS 25.0 software package. RESULTS: The average dmft of children before treatment was 14.02. Patients with supplemental feeding during sleep and additional bottle feeding in the first 6 months had higher dmft. The incidence of caries relapse was 25.67% after 3 months and 50% after 6 months. Caries activity decreased dramatically after treatment. Among three follow-up results, Cariostat scores at the 3rd month were the lowest. After general anesthesia, the eating frequency and sweets intake decreased obviously, and the time for tooth-brushing was longer, while the children's mealtime was significantly shorter. The number of children in normal BMI range significantly increased after dental general anesthesia. CONCLUSIONS: Dental general anesthesia can reduce caries activity and improve oral health behavior, nutritional status, physical and mental health of children in a short term. However, a large number of patients were still at a high risk of caries relapse after treatment.

[Effect of impact direction on the cushion property of mouthguards: a finite element analysis].

PURPOSE: The aim of this study was to evaluate the cushion property of mouthguards when the impact object came from different directions. METHODS: A 3D finite element model of upper central incisor, periodontal ligament and alveolar bone was developed based on cone-beam CT (CBCT) images of a plastic teeth model. The mouthguards were modeled in 5 different thickness (T: 0, 1.5, 3, 4.5 and 6 mm) and a nonlinear dynamic impact analysis, in which the finite element models were collided by a steel ball from different directions (D: angles between the impact direction and the long axis of tooth were 30°, 60°, 90°, 120°, respectively), was performed. The stress cushion efficiency was calculated. RESULTS: The stress cushion efficiency of the mouthguards varied with different thicknesses and impact directions. When T=1.5 mm and 3 mm, the stress cushion efficiency was minimal as D=60° and maximal as D=120°. However, when T=4.5 mm and 6 mm, the stress cushion efficiency was minimal as D=90° and maximal as D=30°. Moreover, the stress cushion efficiency of mouthguards improved with the increasing thickness in each impact direction. CONCLUSIONS: The impact direction affects the stress cushion efficiency of mouthguards, which however is influenced by the thickness of mouthguards.

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.

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.

Effect of a dentifrice containing the peptide of streptococcal antigen I/II on the adherence of mutans streptococcus.

OBJECTIVE: Antigen I/II of mutans streptococcus (MS) is a surface protein, which binds to salivary receptors. The objective of this study was to study the effect of a peptide corresponding to residues 1025-1044 of antigen I/II and a dentifrice containing peptide on the adherence of MS. METHODS: The peptide was synthesized and included into dentifrice. Anti-adherence experiments of the peptide and a dentifrice containing it were processed in vitro and in vivo. RESULTS: The results showed that the adherence of MS to hydroxyapatite was inhibited by synthetic antigen I/II peptide and also by a dentifrice containing the peptide in vitro. The numbers of MS in plaque from subjects treated with dentifrices containing the peptide for 1 month was significantly reduced compared to baseline (log 3.11+/-0.80 vs log 4.09+/-0.90, P<0.01), whereas the control group showed no reduction. CONCLUSION: The adherence of MS to hydroxyapatite was inhibited by both a synthetic peptide and a dentifrice containing the peptide. The peptide dentifrice produced a significant reduction of MS in dental plaque in vivo.