A Modified Photoactivation Protocol Using Two Simultaneous Light-Curing Units for Bonding Brackets to Enamel

This study investigated the effect of a modified photoactivation protocol using two simultaneous light-curing units on the shear bond strength (SBS) of brackets to enamel. Metal brackets were bonded to bovine incisors using the resin-based orthodontic cement Transbond XT (3M Unitek). Four photoactivation protocols of the orthodontic cement were tested (n=15): Control: photoactivation for 10 s on each proximal face of the bracket at a time; Simultaneous: photoactivation for 10 s on both proximal faces of the bracket at the same time; One side-20s: photoactivation for 20 s at one proximal face of the bracket only; and One side-10s: photoactivation for 10 s only at one proximal face of the bracket. SBS was tested immediately or after 1000 thermal cycles. Adhesive remnant index (ARI) was classified. Data were subjected to two-way ANOVA and Student-Newman-Keuls' test (α=0.05). Pooled means ± standard deviations for SBS to enamel (MPa) were: 10.2±4.2 (Control), 9.7±4.5 (Simultaneous), 5.6±3.1 (One side-20s), and 4.6±1.9 (One side-10s). Pooled SBS data for immediate and thermal cycled groups were 6.3±2.6 and 8.8±5.2. A predominance of ARI scores 1-2 and 0-1 was observed for the immediate and thermally cycled groups, respectively. In conclusion, simultaneous photoactivation of the orthodontic cement using two light-curing units, one positioned at each proximal face of the bracket, yielded similar bonding ability compared to the conventional light-curing method. Photoactivation of the orthodontic cement at one proximal face of the bracket only is not recommended, irrespective of the light-curing time used.

Este estudo investigou o efeito de um protocolo modificado de fotoativação utilizando duas unidades de fotopolimerização simultâneas na resistência de união ao cisalhamento (RUC) de braquetes ao esmalte. Braquetes metálicos foram fixados a incisivos bovinos utilizando o cimento ortodôntico resinoso Transbond XT (3M Unitek). Quatro protocolos de fotoativação do cimento ortodôntico foram testados (n=15): Controle: fotoativação por 10 s em cada face proximal do braquete de cada vez; Simultâneo: fotoativação por 10 s em ambas as faces proximais do braquete ao mesmo tempo; Um lado-20s: fotoativação por 20 s em uma face proximal do braquete apenas; e Um lado-10s: fotoativação por 10 s apenas em uma face proximal do braquete. A RUC foi testada imediatamente ou após 1000 ciclos térmicos. O Índice de Remanescente de Adesivo (IRA) foi classificado. Os dados foram submetidos a ANOVA de duas vias e teste de Student-Newman-Keuls (α=0,05). As médias agrupadas ± desvios-padrão de RUC ao esmalte (MPa) foram: 10,2±4,2 (Controle), 9,7±4,5 (Simultâneo), 5,6±3,1 (Um lado-20s), e 4,6±1,9 (Um lado-10s). Os dados agrupados de RUC para os grupos imediatos e termociclados foram 6,3±2,6 e 8,8±5,2. Predominância de escores IRA 1-2 e 0-1 foi observada para os grupos imediatos e termociclados, respectivamente. Em conclusão, a fotoativação simultânea do cimento ortodôntico utilizando duas fontes de luz, uma posicionada em cada face proximal do braquete, gerou similar capacidade de união ao método convencional de fotopolimerização. Fotoativação do cimento ortodôntico em apenas uma face proximal do braquete não é recomendada, independente do tempo de fotoativação utilizado.

Dental emergencies in a university pediatric dentistry clinic: a retrospective study

A significant number of children visit a dentist for the first time due to emergency situations. However, little is known regarding the prevalence, etiology, and treatment provided for children at emergency dental visits. This study aimed to evaluate the profile of children attending a dental school emergency clinic, the reasons for seeking dental care, and the treatment provided. Records of 270 patients who attended an emergency clinic during 2010 were analyzed, and 253 were selected. Demographic, diagnostic, and procedural information was collected. The mean child age was 7.8 years. For 208 children (82%), pain was the main reason for the emergency visit. Nearly 79% of the visits were due to caries, and the most frequently required treatment was endodontic intervention (31.22%). Of the decayed teeth, 61.70% were primary posterior teeth and 31.9% permanent posterior teeth. Pain caused by dental decay was the most frequent chief complaint. A large number of children were brought to the dentist with complaints that had started long before, for which over-the-counter medications had been used.