RESUMO

OBJECTIVES: To evaluate the effect of Nd:YAG laser irradiation as a prior desensitizing strategy on immediate and medium-term microtensile bond strength (µTBS) to simulated hypersensitive dentin. MATERIALS AND METHODS: Flat mid-coronal dentin was obtained from third molars and submitted to a 600-grit SiC paper (1 min; N: normal dentin) or subsequently challenged with citric acid (6%, 1 min; H: simulated hypersensitive dentin). Afterwards, dentin was or was not (C: control; HC, NC - each n = 7) irradiated with Nd:YAG laser (L: laser; 1.0 W/10 Hz/100 mJ/4 irradiations of 50-60 s; HL, NL - each n = 7). A 2-step self-etch adhesive (Clearfil SE Bond) was applied and composite (Filtek Z350) buildups were constructed. After 24-h (distilled water/37 °C) storage, specimens were sectioned into beams and tested (µTBS; 0.5 mm/min) immediately or after 6-month aging. Three-way ANOVA and Tukey tests were applied (α = 0.05). Qualitative evaluation of the adhesive interface (n = 1 extra tooth per group) was performed by Confocal Laser Scanning Microscopy. RESULTS: Substrate condition (p < 0.001), laser irradiation (p < 0.001), and aging (p = 0.002) influenced the results. Furthermore, there was interaction between substrate and irradiation (p < 0.001). Laser irradiation favored µTBS exclusively to hypersensitive dentin immediately and after aging. µTBS to hypersensitive dentin was higher than that to the normal substrate only when it was laser-irradiated. In any case, immediate µTBS was always higher than that after aging. CLSM revealed longer and more numerous resin tags for simulated hypersensitive dentin, and shorter and fewer resin tags for laser-irradiated dentin. No differences were observed in the hybrid layer itself. CONCLUSION: Nd:YAG laser irradiation prior to restoration favored the µTBS of a self-etch adhesive and resin composite to hypersensitive dentin. CLINICAL RELEVANCE: Desensitizing strategies are usually tried before performing restorative treatments in hypersensitive dentin; therefore, they may influence behavior of the adhesive interface established. However, instead of causing concern, Nd:YAG laser irradiation revealed a favorable effect on the aforementioned interface.

Assuntos

Colagem Dentária , Lasers de Estado Sólido , Colagem Dentária/métodos , Cimentos Dentários , Dentina/efeitos da radiação , Adesivos Dentinários/química , Adesivos Dentinários/farmacologia , Teste de Materiais , Cimentos de Resina/química , Cimentos de Resina/farmacologia , Resistência à Tração

RESUMO

Peripheral giant cell granuloma (PGCG) is a nonneoplastic lesion that may affect any region of the gingiva or alveolar mucosa of edentulous and toothed areas, preferentially in the mandible and rarely occurring in children. This report describes the clinical and histopathological findings of a PGCG diagnosed in the maxilla of a 9-year-old boy associated with a tooth erupting improperly and a traumatic habit. The patient did not present anything noteworthy on extraoral physical examination or medical history, but the habit of picking his teeth and "poking" the gingiva. The oral lesion consisted of an asymptomatic, rounded, pink colored, smooth surface, soft tissue injury with fibrous consistency and approximated size of 1.5 cm located in the attached gingiva between the upper left permanent lateral incisor and the primary canine of the same side. Excisional biopsy was performed through curettage and removal of the periosteum, periodontal ligament, and curettage of the involved teeth with vestibular access. The histopathological analysis led to the diagnosis of PGCG. The prompt diagnosis and treatment of the PGCG resulted in a more conservative surgery and a reduced risk for tooth and bone loss and recurrence of the lesion. After four years of control, patient had no relapse of the lesion and good gingival and osseous health.