RESUMO
AIMS: This study investigated the effect of stainless steel bands on cuspal flexure and fracture resistance of extracted maxillary premolars. METHODOLOGY: Twenty extracted maxillary premolars (10 matched pairs) with mesio-occluso-distal (MOD) cavities and endodontic access were subjected to occlusal loading tests (100 N) using a servo-hydraulic testing machine. Cuspal deflections were measured by an extensometer, with and without the band present. Ten teeth (one of each pair) then had the band removed, and all teeth were subjected to loading until fracture. RESULTS: Mean cuspal flexure of teeth with bands was one-half of flexure without bands (P < 0.001). Teeth with bands fractured at higher load than their matched pairs with the band removed (P < 0.001), with mean loads at fracture of 1282 N and 729 N, respectively. CONCLUSIONS: The study showed that stainless steel bands used in endodontics reduce the cuspal flexure of maxillary premolars and increase their fracture resistance.
Assuntos
Dente Pré-Molar/fisiologia , Esmalte Dentário/fisiologia , Bandas de Matriz , Aço Inoxidável , Adolescente , Força de Mordida , Estudos de Casos e Controles , Criança , Preparo da Cavidade Dentária/instrumentação , Análise do Estresse Dentário/instrumentação , Desenho de Equipamento , Humanos , Modelos Lineares , Análise por Pareamento , Maleabilidade , Preparo de Canal Radicular/instrumentação , Estatística como Assunto , Estresse Mecânico , Fraturas dos Dentes/fisiopatologiaRESUMO
Stainless steel bands are commonly advocated to protect posterior teeth against fracture during endodontic treatment and before final restoration. A poorly fitting band, however, may lead to a compromised coronal seal and gingival irritation. This radiographic study assessed the quality of fit and marginal adaptation in the proximal area of stainless steel bands placed during routine endodontic treatment. Clinical radiographs of 120 maxillary and mandibular premolars and molars were evaluated. All radiographs were taken during routine clinical endodontic treatment and randomly selected from cases completed by ten operators. Approximately one-half of cases did not meet the criteria of adequate marginal seal (mesial: 65/120; distal: 49/120). Only 11 teeth were found to have adequate fit of the band on both mesial and distal aspects of the tooth. The most common reason for inadequacy of fit was lack of band adaptation to the tooth contour in the cervical region. Stainless steel bands have a high possibility of poor marginal fit and should be used with the awareness that they may produce other clinical problems.
