Effects of Dentine Pretreatment Solutions Containing Flavonoids on the Resin Polymer-Dentine Interface Created Using a Modern Universal Adhesive.

The aim of the present study was to evaluate the influence of several experimental pretreatment crosslinker solutions on the resin polymer-dentine interface created using a representative universal adhesive system, by means of microtensile bond strength testing (µTBS), nanomechanical properties and ultramorphology confocal laser scanning microscopy (CLSM). Five experimental solutions containing different flavonoids were applied as dentine pretreatment after acid etching. A control pretreatment group containing no flavonoid was also employed. A representative modern universal adhesive was then applied, followed by a 3 mm thick composite built up. Specimens were sectioned into sticks and submitted to a µTBS test or nanoindentation analysis along the interface (24 h or 25,000 thermocycles). The ultramorphology of the polymer-resin interface was also evaluated using CLSM. The results were analyzed using two-way ANOVA and Bonferroni's post hoc test (α = 0.05). All flavonoids improved short- and long-term µTBS values (p < 0.01), while only some specific such solutions improved the nanomechanical properties (p < 0.05) and preserved the structural morphology of the interface after aging. Pretreatment of acid-etched dentine using specific flavonoid-containing solutions may be a promising approach to improve both the nanomechanical properties and the durability of modern universal adhesive systems.

Clinical performance of a micro invasive treatment based on demineralization-remineralization for dental fluorosis: case report

Introduction: Dental fluorosis manifests clinically as white to brown spots on the enamel teeth that were exposed to excessive fluoride during the formation process. Esthetic treatments were described in the literature to reduce or eliminate the fluorotic stains on the enamel surface. Objective: The aim of this study is to present an alternative treatment for fluorosis-stained teeth. Case report: This case report describes the clinical performance of a treatment of a 12-year-old male patient whose teeth presented moderate fluorosis. This treatment is based on tooth demineralization and remineralization. The material has an acid phase made by hydrochloric acid with tricarboxylic acid, and an alkaline phase made by Calcium Hydroxide. Results: This pain less and fast treatment presented good results. The treatment eliminated the spots during the follow-up and preserved most of the dental structure, improving the appearance of the patient's teeth. Conclusion: The appearance of the treated enamel showed a surface almost completely free of fluorotic stains, demonstrating the satisfactory results of this treatment.

Introdução: A fluorose dentária manifesta-se clinicamente como manchas brancas a marrons no esmalte de dentes expostos ao excesso de flúor durante o processo de formação. Tratamentos estéticos foram descritos na literatura para reduzir ou eliminar as manchas fluoróticas na superfície do esmalte. Objetivo: Apresentar uma alternativa de tratamento para dentes manchados por fluorose dentária. Relato do caso: Este relato de caso descreve o desempenho clínico do tratamento para dentes com fluorose moderada em um paciente de 12 anos. Esse tratamento foi baseado numa técnica de desmineralização e remineralização do dente. O material possui uma fase ácida composta por ácido clorídrico com ácido tricarboxílico, e uma fase alcalina composta por Hidróxido de Cálcio. Resultados: Observou-se que esse tratamento, sem dor e rápido, apresentou resultados satisfatórios, pois eliminou as manchas durante o acompanhamento. Além disso, preservou ao máximo a estrutura dentária, beneficiando o paciente com uma melhor aparência dos seus dentes. Conclusão: O aspecto do esmalte tratado mostrou uma superfície quase sem manchas fluoróticas, demonstrando resultados satisfatórios deste tratamento.

Influence of flavonoids on long-term bonding stability on caries-affected dentin.

OBJECTIVES: To evaluate the effect of experimental dentin pre-treatment solutions formulated with different flavonoids on microtensile bond strength (µTBS), nanohardness (NH) and ultra-morphological characteristics of artificial caries-affected dentin (CAD) bonded using a universal bonding system. METHODS: A microbiological method was used to create an artificial CAD in 91 human molars. Five experimental pre-treatment solutions were created using the following flavonoids: quercetin (QUE); hesperidin (HES); rutin (RUT); naringin (NAR), or proanthocyanidin (PRO). A placebo solution (PLA) with no flavonoids added was also evaluated. The flavonoids or placebo solutions were applied to the CAD prior to the application and photoactivation of a universal adhesive (Scotchbond Universal, 3M Oral Care). A control group (CON), in which only the bonding agent was applied without any flavonoid solution, was also evaluated. A 3-mm-thick block of resin composite (Opallis, FGM) was built up on the flat bonded CAD surfaces and was light-cured following the manufacturer's instructions. Specimens were sectioned to obtain resin-dentin slices and sticks (cross-sectional area of 0.8 mm2). The µTBS, NH, and confocal ultramorphology analysis of resin-dentin interface was evaluated at 24 h and after thermo-cycling aging (25,000 cycles). The results were analyzed using 2-way ANOVA followed by Bonferroni's post hoc test (pre-set α = 0.05). RESULTS: The specimens from groups QUE, NAR, and RUT presented greater µTBS values than those from CON group (p<0.05). Specimens from some of these experimental groups presented greater nanomechanical properties (p<0.05), and no morphological degradation at the resin-dentin interface after aging. SIGNIFICANCE: The use of exogenous cross-linkers as dentin pre-treatment before bonding procedures may represent a suitable strategy to improve the longevity of universal adhesive systems applied to caries-affected dentin.