RESUMO
Aim: The aim of this study was to evaluate whether 2.5% chitosan applied after dentin acid etching or incorporated into the adhesive system interferes with the microtensile strength of the interface tooth-resin. Subjects and Methods: Sixty healthy bovine teeth had the incisal thirds and the roots sectioned and were randomly allocated into three groups (n = 60). G1 (control): acid attack + Clearfil SE Bond + Z350 resin; G2: treatment with 2.5% chitosan + Clearfil SE Bond + Z350 resin; G3: treatment with 2.5% chitosan incorporated into dentin adhesive + Z350 resin. The stick-shaped specimens made in each group were randomly divided into two subgroups and subjected to degradation of the adhesive interface (with aging: specimens immersed in 2.5% sodium hypochlorite for 12 h and washed in distilled water for 1 h, and without aging). The groups were submitted to a microtensile strength test with a 0.5 mm/min speed until rupture. Statistical analysis of the data was performed according to normal distribution. Results: Microtensile data were obtained by calculating the area of each toothpick, obtaining values in megapascal. No aging: G1 - 5251.69, G2 - 5.52 ± 1.46, and G3 - 3.91 ± 1.21. With aging: G1 - 3.45 ± 1.29, G2 - 2.75 ± 0.78, and G3 - 3.53 ± 1.33. Statistical analysis showed that the aging factor and adhesive modification decreased the bonding strength of the resin-dentin (P = 0.001). As well, the interaction between the analyzed factors showed statistically significant differences (P = 0.002). Conclusions: Accelerated aging decreases the adhesion strength in G1, even when chitosan is previously applied to the adhesive system. However, when adding chitosan to the adhesive, adhesion remained similar after aging but lower when compared to the other groups.
RESUMO
Biological restorations, involving a technique of uniting autogenous or homogenous dental fragment for use as the primary restorative material, are an alternative for morphological and functional reestablishment of teeth with extensive coronal destruction. Despite the wide range of restorative materials available in dentistry, no material has proved to be as efficient as the natural tooth structure. This article illustrates a therapeutic option for rehabilitating a devitalized mandibular tooth with a weakened coronal remainder by using the biological restoration technique. The authors present the sequence of planning and performing the technique, such as the characteristics of preparation of the tooth and fragment, impression taking, cutting and cementation of the fragment, and the four-year follow-up of the biological restoration, which shows the success of the technique with marginal adaptation and satisfactory esthetic appearance. (AU)
As restaurações biológicas, envolvendo uma técnica de união de fragmentos dentários autógenos ou homogêneos como principal material restaurador, são uma alternativa para o restabelecimento morfológico e funcional de dentes com destruição coronal extensa. Apesar da ampla gama de materiais restauradores disponíveis na odontologia, nenhum material provou ser tão eficiente quanto a estrutura dentária natural. Este artigo ilustra uma opção terapêutica para reabilitar um molar inferior desvitalizado com um remanescente coronal fragilizado, utilizando a técnica de restauração biológica. Os autores apresentam a sequência de planejamento e execução da técnica, tais como as características de preparação do dente e do fragmento, moldagem, recorte e cimentação do fragmento, e o acompanhamento clínico de 3 anos da restauração biológica, mostrando o sucesso da técnica com uma adaptação marginal e aparência estética satisfatória (AU)