Effect of treatment of transverse maxillary deficiency using rapid palatal expansion on oral health-related quality of life in children: A randomized controlled trial.

INTRODUCTION: This trial aimed to longitudinally evaluate the effect of the treatment of transverse maxillary deficiency using rapid palatal expansion (RPE) on self-perceived oral health-related quality of life (OHRQOL) in children. METHODS: Eighty participants aged 8-10 years with transverse maxillary deficiency and bilateral posterior crossbite were randomly assigned to 2 groups (n = 40 each): a group treated with RPE using hyrax-type appliances and a nontreated control group. OHRQOL was assessed by using the Child Perceptions Questionnaire for 8-10-year-olds at 4 times: before RPE, during RPE (T1), at the end of RPE (T2), and 1 month after the appliance removal (T3). Generalized mixed models were used for data analysis (α = 0.05). RESULTS: Both groups exhibited similar demographic characteristics and OHRQOL scores at baseline. All participants completed the study. RPE had a time-dependent effect on OHRQOL. At T1 and T2, this therapy is expected to increase the overall OHRQOL scores by 1.17 times (ie, ∼17% increase; T1 95% confidence interval [CI], 1.08-1.26; T2 95% CI, 1.09-1.27; P = 0.001). In contrast, the overall OHRQOL scores at T3 are expected to be 0.28 times the baseline scores (ie, ∼72% reduction; T3 95% CI, 0.26-0.31; P = 0.001). All individual domains of the OHRQOL evidenced a positive impact of treatment at T3 (P = 0.001). Only the oral symptoms and social well-being domains showed a significantly negative impact of the treatment at T1 and T2. CONCLUSIONS: Correction of the transverse maxillary deficiency by RPE in children aged 8-10 years improves OHRQOL. There is a temporary worsening of OHRQOL during the treatment of this condition using RPE. REGISTRATION: This trial was not registered. PROTOCOL: The protocol was not published before trial commencement. FUNDING: This study was financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brazil, Financing Code 001.

Force decay of latex and non-latex intermaxillary elastics: a clinical study.

OBJECTIVE: To evaluate force decay between intermaxillary orthodontic elastics with and without latex in the oral medium at different time intervals. MATERIALS AND METHODS: Intermaxillary orthodontic elastics with and without latex [1/8″ (3.2mm), 1/4″ (6.35mm), and 5/16″ (7.94mm) in diameter] were evaluated 'clinically'. For this purpose, 26 patients served as hosts for the elastics during the evaluation period. Initially, 52 thermoplasticized plates 1mm thick were made according to the patients' mould. Then, the orthodontic accessories were bonded to the plates, which kept the elastics distended throughout the experimental period. The force released by the elastics at this distance was evaluated at 0, 12, and 24 hours. Statistical analyses were performed using the Friedman, Wilcoxon, and Mann-Whitney tests (significance set at 5 per cent). RESULTS: Elastics with and without latex presented with permanent deformation and increasing internal diameter throughout the entire period. Elastics with latex, 1/8″ (3.2mm) in diameter, sustained higher levels of force than those without latex. Elastics measuring 1/4″ (6.35mm) and 5/16″ (7.94mm) in diameter without latex sustained higher levels of force at 0 and 12 hours compared to those with latex. At the end of the experiment (24 hours), no significant difference was observed between the elastics (P > 0.05). LIMITATIONS: This study only evaluated three time intervals: 0, 12, and 24 hours. If the behaviour was evaluated at different time intervals, different behaviours of these materials might be revealed. CONCLUSION: Elastics with latex 1/8″ in diameter sustained a higher level of final force than the corresponding type without latex. The 1/4 and 5/16 elastics with and without latex were not different at the end of the evaluation period.

Brazilian primary school teachers' knowledge about immediate management of dental trauma.

OBJECTIVE: To assess the level of knowledge of primary school teachers in the public school network of Northeastern Brazil with respect to management of dental trauma and its relationship with prognosis. METHODS: A questionnaire was applied to 195 school teachers of public schools in Northeastern Brazil. The questionnaire comprised 12 objective questions about dental trauma and methods for its prevention and management. Data were submitted to chi-square test and Poisson regression test (P > 0.05). RESULTS: Out of the 141 teachers who responded the questionnaires, the majority were women (70.2%) and most of them had experienced previous dental accidents involving a child (53.2%). The majority (84.4%) had incomplete college education and few were given some training on how to deal with emergency situations during their undergraduate course (13.5%) or after it (38.3%). Their level of knowledge about dental trauma and emergency protocols showed that unsatisfactory knowledge level was associated with the male sex: 46% higher for men in comparison to women (P = 0.025). CONCLUSIONS: Approximately half of teachers evaluated had unsatisfactory knowledge about dental trauma and emergency protocols, with female teachers showing more knowledge than men.

The influence of pH levels on mechanical and biological properties of nonlatex and latex elastics.

OBJECTIVE: To evaluate the influence of pH levels on interarch elastics with regard to force decay and cytotoxicity. MATERIALS AND METHODS: One nonlatex (NLAO) group and one latex (LAO) group were tested (n  =  10). Elastics were stretched to 25 mm and were held for 1, 6, 12, and 24 hours in artificial saliva solutions with pH levels of 5.0, 6.0, and 7.5. Force magnitudes were measured at 25 mm of activation. The cytotoxicity assay was performed using cell cultures (L929 mouse fibroblast cell line), which were subjected to the cell viability test with neutral red ("dye-uptake"). Force decay and cytotoxicity were assessed using analysis of variance, the Sidak method, and a Tukey's test. RESULTS: The interactions between group, pH, and time showed no statistically significant differences (P  =  .29). When pH per time (P  =  .032) and group per time (P  =  .0009) were considered, these interactions showed statistically significant differences (P < .05). The pH did not interfere directly in the degradation results of the tested elastics. The cytotoxicity test showed that group LAO presented lower cell viability when compared with group NLAO over the course of the entire experiment. There was a gradual reduction in cell viability from 1 hour to 24 hours. A significant difference (P < .05) was found between the interactions group pH and the control group of cells, except between group NLAO at the time point of 1 hour at different pH values and at the time points of 6 and 12 hours with pH 5 (P > .05). CONCLUSIONS: No significant correlation between pH, force decay, and cytotoxicity was observed.