Fracture Resistance and Gap Formation of MOD Restorations: Influence of Restorative Technique, Bevel Preparation and Water Storage

Abstract

©Operative Dentistry, 2008, 33-1, 37-43 SUMMARYThis in vitro study evaluated the effect of technique, use of a bevel and thermal cycling on the fracture resistance and gap formation of resin composite MOD restorations. Fracture resistance was measured on standard MOD cavities prepared in 100 upper premolars that were stored for 24 hours and 6 months with 1000 thermal cycles. Subgroups (n=10) were: beveled or nonbeveled preparations and direct restorations (Adper Single Bond/Filtek Z250) and indirect restorations (prepolymerized Filtek Z250 cemented with Rely X ARC). Ten sound teeth and 10 specimens with MOD preparations without restorations served as the positive and negative controls, respectively. The specimens were subjected to axial compression in a universal testing machine at a crosshead speed of 0.5 mm/minute. Failure patterns were analyzed by stereomicroscopy (40x). To evaluate gap presence or absence, proximal box cavities were prepared in 24 human third molars that were restored as described above. The specimens were evaluated under SEM examination after 24 hours and six months. Data were statistically analyzed by ANOVA and multiple comparison tests at the 0.05 level of significance. After 24 hours, the beveled restorations exhibited higher fracture strength values than the non-beveled restorations, and all groups FH Coelho-de-Souza • GB Camacho FF Demarco • JM Powers Clinical RelevanceBeveling of the cavosurface margin can improve resistance to fracture and the marginal adaptation of posterior composite restorations, reducing the deleterious effect of storage with thermal cycling on restoration quality. Generally, indirect restorations showed similar performance compared to direct restorations.

Antibacterial activity and ion release of bonding agent containing amorphous calcium phosphate nanoparticles

“…Advances in polymers and fillers have significantly enhanced the composite properties and clinical performance [5–11]. However, a serious drawback is that composites tend to accumulate more biofilms/plaques in vivo than tooth enamel and other restorative materials [12,13].…”

Compressive strength and failure types of cusp replacing direct resin composite restorations in previously amalgam-filled premolars versus sound teeth

“…While some studies reported higher fracture resistance for direct [9] and indirect resin composite restorations [10], other studies revealed no significant differences [11,12].…”

Conhecimento de cirurgiões- dentistas sobre o diagnóstico e o tratamento de lesões cervicais não cariosas: um estudo piloto em rede colaborativa

“…A técnica visa basicamente aumentar a área de exposição dos prismas de esmalte com o intuito de aumentar a retenção da restauração e mascarar a interface entre o esmalte e o composto a fim de melhorar a estética. A única desvantagem descrita desse procedimento é que há a necessidade de desgaste de uma pequena quantidade de estrutura dental 33 . Cavidades preparadas com bisel em esmalte apresentam comportamento semelhante ao das que não foram biseladas, mas proporcionam melhor vedamento marginal, diminuindo a microinfiltração 34 .…”