Alexandra Vinagre

Cuspal Displacement Induced by Bulk Fill Resin Composite Polymerization: Biomechanical Evaluation Using Fiber Bragg Grating Sensors

Polymerization shrinkage is a major concern to the clinical success of direct composite resin restorations. The aim of this study was to compare the effect of polymerization shrinkage strain of two resin composites on cuspal movement based on the use of fiber Bragg grating (FBG) sensors. Twenty standardized Class II cavities prepared in upper third molars were allocated into two groups (n = 10). Restorations involved the bulk fill placement of conventional microhybrid resin composite (Esthet•X® HD, Dentsply DeTrey) (Group 1) or flowable “low-shrinkage” resin composite (SDR™, Dentsply DeTrey) (Group 2). Two FBG sensors were used per restoration for real-time measurement of cuspal linear deformation and temperature variation. Group comparisons were determined using ANCOVA (α = 0.05) considering temperature as the covariate. A statistically significant correlation between cuspal deflection, time, and material was observed (p < 0.01). Cuspal deflection reached 8.8 μm (0.23%) and 7.8 μm (0.20%) in Groups 1 and 2, respectively. When used with bulk fill technique, flowable resin composite SDR™ induced significantly less cuspal deflection than the conventional resin composite Esthet•X® HD (p = 0.015) and presented a smoother curve slope during the polymerization. FBG sensors appear to be a valid tool for accurate real-time monitoring of cuspal deformation.

Mandibular condylar hyperplasia: diagnosis and management. Case report

JUSTIFICATIVA E OBJETIVOS: A hiperplasia da cabeca mandibular e uma doenca na qual ha um crescimento excessivo da cabeca, ramo e corpo mandibulares que causa assimetria facial. A sua abordagem terapeutica nao apresenta um consenso e, dada a sua complexidade, constitui um desafio para o cirurgiao maxilofacial e para o ortodontista. O objetivo deste estudo foi discutir os aspectos clinicos, diagnosticos e terapeuticos envolvidos na abordagem dessa doenca, clarificando o papel da condilectomia. RELATO DO CASO: Paciente do genero feminino, 19 anos, caucasiana, procurou atendimento de um Cirurgiao Maxilofacial devido a assimetria facial e dor na articulacao temporomandibular direita. Nao possuia antecedentes medicos ou gestacionais ou familiares de deformidade facial, nem historia de trauma ou infeccao articular previos. Apresenta-se um caso clinico de alongamento hemimandibular tratado com condilectomia. CONCLUSAO: A condilectomia e um procedimento seguro e eficaz, sem sequelas articulares funcionais, que evita a progressao da deformidade dentofacial, minimizando o seu impacto psicossocial e facilitando o tratamento posterior.

Adhesion in Restorative Dentistry

Bonding agents play a crucial role in the effective sealing and retention of resin-based composite restorations, which have been increasingly placed and replaced by dentists in many countries around the world. In fact, direct adhesive restoration with composite resins has become the procedure of choice for the treatment of anterior and posterior teeth. However, long-term durability of those restorations may be compromised due to progressive loss of the integrity of adhesive interfaces. This means that no adhesive strategy is free from technique sensitivity. The specificity and proportion of different constitutive molecules, the interaction between them and substrates can differ greatly from one class of adhesive system to another, which can affect bond quality. Protocol simplification has been an inevitable trend that has boosted the use of self-etching and universal systems in adhesive dentistry. However, there is a lack of randomized clinical trials to prove the effectiveness of these systems. This chapter gives an overview of the most important issues in dental adhesion and adhesive systems, as well, discussing their composition and clinical use.