Enamel loss and superficial aspect during bonding and debonding of metallic brackets

Abstract

ABSTRACT:To evaluate the cumulative enamel loss during bonding and debonding procedures of orthodontic metallic brackets and to analyze the enamel superficial roughness. Forty-seven maxillary first premolars were obtained for quantitative and qualitative analysis. For quantitative analysis, forty premolars were weighed at each stage of treatment and the equivalent thickness of enamel loss was measured. The amount of tooth mass loss in each stage was divided by the density value to obtain the corresponding enamel volume lost. Subsequently, these volumes were divided by a circular area with a diameter of 7 mm, thus obtaining the equivalent thickness of enamel loss. They were assessed under the following conditions: as sound enamel, after acid conditioning, following the removal of residual resin composite, after final polishing with high or low-speed, and with or without water refrigeration. A rugosimeter was used to obtain a graphic registration of the enamel superficial roughness before and after acid conditioning. The data were analyzed with the Quantikov software and the Shapiro Wilk's and Wilcoxon statistical tests were used to evaluate enamel superficial roughness. The one-way ANOVA followed by Bonferroni Post-Hoc tests were used to analyze the amount of enamel loss. For qualitative analysis, scanning electron microscopy (SEM) of the enamel surfaces was performed on seven premolars, one in each step. Acid conditioning significantly increased enamel surface roughness (p<0.01). Based on the dental mass weighed after each stage of evaluation, enamel loss was statistically significant in all stages (p<0.01). However, when the 4 different final polishing methods were compared, no statistically significant differences were registered regarding loss of mineralized structure (p=0.72). The SEM analysis revealed that the tungsten-carbide bur with water refrigeration and lowspeed rubber points caused less damage to the enamel. The greatest amount of enamel loss was due to acid conditioning. The losses relative to abrasion with composite removal or after the 4 polishing protocols were similar. Finally, none of the enamel surfaces was restored to their original aspects after bonding and debonding metallic brackets.

Evaluation of enamel surface changes by different enamel conditioners and de-bonding procedure using optical coherence tomography: An in-vitro qualitative study

“…Here, enamel conditioning with 37% phosphoric acid caused enamel loss of 6 to 12μm. These results are similar to study conducted by Ferreira EF et al 21 who reported variations in enamel loss of about 4 to 17μm.…”

“…Forces applied to base of the bracket and to adhesive created stress concentration regions within the enamel that caused separation at the adhesive-enamel interface. Studies by Ferreira EF et al 21 and Retief DH and Denys FR [22] found similar results. OCT images showed residual adhesive resin irregularly adhered on the enamel surface after de-bonding of metallic bracket.…”

Avaliação dos Efeitos da Remoção da Resina Residual e do Polimento na Superfície do Esmalte após Descolagem do Braquete

“…A remoção de remanescentes resinosos da superfície dentária com o uso de instrumentos rotatórios, após o tratamento ortodôntico, podem, eventualmente, causar danos ao esmalte (2,6,9,11,13,15) e perda de estrutura superficial com exposição das terminações do prisma do esmalte para o ambiente bucal, acúmulo de placa bacteriana e pigmentos nas microfissuras, podendo causar uma diminuição da resistência superficial aos ácidos orgânicos e isso, eventualmente, torna o esmalte mais propenso à desmineralização e resulta em manchas na interface resina/esmalte (1,2,6,9,12,14,(16)(17)(18), podendo acarretar risco de danos irreversíveis ao esmalte (3,8,10,19). Por isso, é preciso considerar a importância de se tentar, após a remoção da resina residual do esmalte, restaurar a superfície tão próxima quanto possível das condições do pré-tratamento (9), apesar de nenhuma superfície do esmalte ter sido restaurada ao seu aspecto original (19). A hipótese de que o uso de brocas para a remoção da resina residual agride e altera a superfície do esmalte se confirmou neste estudo.…”

“…Embora não tenha observado consenso na literatura, a forma mais comum de remover resíduos de adesivo, após a remoção ortodôntica, é por meio de brocas de carbeto de tungstênio (1), sendo que esta opção foi sugerida por diversos autores (7,16,(19)(20)(21)(22)(23)(24)(25).…”

Comparative study of the usability of two software programs for visualization and analysis of digital orthodontic models

“…Although the present study has focused on issues related to diagnosis and treatment planning, it should be remembered that orthodontic treatment itself also brings with it undesirable side effects, such as tooth enamel wear and patient hygiene difficulties. 45 , 46 Ways to control them, even in the details of each procedure, can help the clinician beware of possible litigation.…”