Aim: To evaluate the influence of the biomodification of erosive lesions with a chitosan nanoformulation containing green tea (NanoCsQ) on the clinical performance of a composite resin. Methods: The study was performed in a split-mouth, randomized and double-blinded model with 20 patients with 40 erosive lesions. The patient’s teeth were randomized into two groups (n=20) according to the surface treatment: 1) Without biomodification (control), and 2) Biomodification with NanoCsQ solution (experimental). The lesions were restored with adhesive (Tetric N-bond, Ivoclar) and composite resin (IPS Empress Direct, Ivoclar). The restorations were polished and 7 days (baseline), 6 months, and 12 months later were evaluated according to the United States Public Health Service (USPHS) modified criteria, using clinical exam and photographics. Data were analyzed by Friedman’s and Wilcoxon signed-rank tests. Results: No significant differences were found between the control and experimental groups (p=0.423), and also among the follow-up periods (baseline, six months, and 12 months) (p=0.50). Regarding the retention criteria, 90% of the restoration had an alpha score in the control group. Only 10% of the restorations without biomodification (control) had a score charlie at the 12-month follow-up. None of the patients reported post-operatory sensitivity. Conclusion: The NanoCsQ solution did not negatively affect the performance of the composite resin restorations after 12 months.

Aos meus paisFrancino Gonçalves dos Reis e Carolina Fernandes dos Reis, meus exemplos, minha base, pelo zelo que sempre tiveram por mim, pela paciência e o amor que nunca me foi negado. O amor que sinto por vocês não cabe em palavras. Sou eternamente grato por tudo! A minha esposa Patrícia Bressan dos Reis e aos meus queridos filhos Carolina Bressan dos Reis e Bruno Bressan dos Reis, que com muito amor carinho tenho a oportunidade de compartilhar os melhores momentos de minha vida. Aos meus irmãos Fernando Gonçalves dos Reis, Ana Maria Gonçalves dos Reis e Márcio Rogério Gonçalves dos Reis pelo amor e companheirismo compartilhado. Aos meus amigos que estiveram presentes durante o mestrado, companheiros de trabalho e almoço. Agradeço em especial, ao meu grande amigo que tive a felicidade de conhecer, Thiago Vinicius Cortez, pelo apoio, companheirismo, conselhos, momentos de alegria e dificuldade compartilhados durante esta jornada.