Enamel development defects and oral symptoms: A hierarchical approach.

OBJECTIVE: This study aimed to determine the relationship between enamel developmental defects (DDEs) and children's oral symptoms in the early and late mixed dentition in a hierarchical approach. METHODS: Population-based cross-sectional study of 772 children. Calibrated dental examiners examined for DDEs, malocclusion, and dental caries. Parents answered questions related to the socioeconomic condition of the family. The Child Perception Questionnaire (CPQ8₋10) was used to identify oral symptoms as the outcome variable. Analysis was adjusted in a backward stepwise hierarchical multiple logistic regression model. RESULTS: Symptoms were predicted by being female, having a father with low education and having DDEs in the upper first molars (ORs = 1.42; 95% CI: 1.06-1.89; 1.46: 1.10-1.96 and 2.02: 0.99-4.05 respectively). CONCLUSION: DDEs are associated with oral symptoms in Brazilian children.

Zoledronic acid and alendronate sodium and the implications in orthodontic movement.

OBJECTIVE: To evaluate orthodontic tooth movement (OTM) in rats treated with two types of bisphosphonates (BPs), alendronate sodium (A) and zoledronic acid (Z). DESIGN: In all, 15 male Wistar rats were randomly divided into three groups. Group OTM+A: orthodontic tooth movement and subcutaneous administration of alendronate sodium (2.5 mg/kg); Group OTM+Z: orthodontic tooth movement and subcutaneous administration of zoledronic acid (0.02 mg/kg), and Group OTM: orthodontic tooth movement and subcutaneous injection of saline. The BPs were administered once a day during 25 days before OTM started and during 10 days of OTM. The left upper first molar was moved with a stainless-steel closed coil spring which delivered an initial force of 0.4N. OTM was measured with a digital caliper comparing the moved and the contralateral side. The histomorphometric analysis counted the number of osteoclasts, inflammatory cells, blood vessels and fibroblasts (n/104  m2 ) in periodontal ligament (PDL) of the distobuccal root. RESULTS: A reduction of 58.3% of OTM was found in Group OTM+A and 99.6% in Group OTM+Z, when compared with Group OTM. There was a significant decrease of osteoclasts and inflammatory cells in BP-treated groups. Blood vessels and fibroblastic cells decreased mainly in Group OTM+Z. CONCLUSION: Alendronate sodium and zoledronic acid have similar effects on the periodontal tissue during orthodontic treatment in rats. Especially, zoledronic acid can affect orthodontic tooth movement.

Real-time three-dimensional jaw tracking in temporomandibular disorders.

When a dysfunction occurs in any component of the stomatognathic system, temporomandibular disorders (TMD) may originate. The aim of this study was to compare the deviations, displacement and the execution speed of mandibular movements among asymptomatic participants and those with TMD. Convenience sampling was used; forty participants diagnosed by clinical evaluation following the Research Diagnostic Criteria for Temporomandibular Disorders were divided into three groups: arthropathy (GART, 10 participants, 40% men), myopathy (GMYO, 10 participants, 30% men), and the control group (CG, 20 asymptomatic participants, 25% men). Participants were asked to perform the movements of free maximal mouth opening and closing, right and left lateral excursions, and protrusion with sliding teeth contacts. The mandibular trajectory was recorded using opto-electronic devices tracking reflective markers placed in front of the 'soft tissue pogonion point'. The movements were analysed on the following axis: x - medial-lateral, y - vertical, z - antero-posterior. Significative differences were found in CGxGART - unassisted maximal mouth opening and closing projection on y-axis (OCY), CGxGMYO - unassisted maximal mouth opening and closing projection on x-axis (OCX), and in the measures Opening lateral deviation on x-axis (OLDX), closing lateral deviation on x-axis (CLDX) and in the measures of speed for both. In regard to GARTxGMYO, a significative difference was found in Protrusion lateral deviation on x-axis (PLDX) 'Conover-Iman Test of Multiple Comparisons Using Rank Sums' using Bonferroni correction (P < 0·05). In conclusion, the total opening movements in individuals with TMD tended to have higher deviation than in those asymptomatic individuals and a reduction in the speed of movements.

ER: YAG laser for composite removal after bracket debonding: a qualitative SEM analysis.

OBJECTIVE: To qualitatively compare the effectiveness of the Er:YAG laser with conventional methods for removing the composite remnants and the enamel ablation produced after bracket debonding. MATERIALS AND METHODS: Brackets were bonded on 12 extracted premolars and the composite remnants were removed by 3 different methods: tungsten-carbide bur and 2 Er:YAG laser intervals. Four other premolars were used as a control group. Samples were analyzed with scanning electron microscopy (SEM) and the amount of composite remaining on the teeth and the amount of enamel ablated on each sample were qualitatively ranked by 3 examiners. The results were statistically analyzed by the Tukey test. RESULTS: The Er:YAG laser performed significantly better than the conventional technique for removing the composite remnants, but the amount of enamel ablation produced was significantly higher. CONCLUSIONS: The Er:YAG laser can be used to remove composite remnants after orthodontic bracket debonding, but further studies are required to determine the ideal specifications of this type of laser to reduce the amount of enamel ablation produced under the specifications used in this study.

Prevalence of malocclusions in a young Brazilian population.

Malocclusions are generally treated in adolescents and adults, but they are established at an early age. The purpose of this study was to determine the prevalence of malocclusions in a young Brazilian population. The sample included 926 children, 8 to 12 years old, attending 5 public schools in the state of Goias, Brazil The type of occlusion was visually determined during the oral exam and statistical analysis, Chi-square test, was performed to correlate the prevalence of malocclusion with gender and with age. 819 patients out of the 926 patients had some type of malocclusion. From those, 513 patients had a class I malocclusion, 201 patients were classified as class II malocclusion, and 105 patients were class III malocclusion. Vertically, 62 patients showed a deep bite and 61 patients had an open bite. Transversely, 40 patients presented a bilateral posterior crossbite, 54 patients had a posterior crossbite on the left side, and 39 patients had a posterior crossbite on the right side. No significant correlation between gender and malocclusions was found and the number of patients with malocclusions between boys and girls were similar. Considering the three spatial planes, there is a high prevalence of malocclusions among the young Brazilian population. Therefore, the dental community must improve health policies and treat malocclusions earlier.