331 Prevention of Enamel Intrinsic Erosion Employing Nd:YAG Laser Irradiation

Thursday, March 22, 2012: 2 p.m. - 3:15 p.m.
Presentation Type: Poster Session
J. FARAONI-ROMANO, Universidade de Sao Paulo, Ribeirão Preto, Brazil, J.D.R. DERCELI, Restorative Dentistry, University of São Paulo, Ribeirão Preto, Brazil, C. LEPRI, University of São Paulo, Ribeirão Preto, Brazil, J. PECORA, Faculdade de Odontologia de Ribeirão Preto, USP, Ribeirão Preto, Brazil, and R.G. PALMA-DIBB, Departamento de Odontologia Restauradora, Faculdade de Odontologia de Ribeirao Preto, Ribeira Preto, SP, Brazil
Objectives: The aim of this study was to evaluate the effect of  Nd:YAG laser  associated or not with topical acidulated phosphate fluoride gel preventing from enamel erosion caused by hydrochloric acid.

Methods: Enamel slabs (4mm x 4mm x 2mm) were cut from bovine incisors, ground flat, polished and based upon their Knoop microhardness values 40 specimens were selected. All the samples were isolated with nail varnish/wax except half of their outer surface (8mm2), and were randomly divided in 4 groups (n=10) according to the following treatments: G1 – no treatment (control) ; G2 – 1.23% acidulated fluoride gel; G3 – Nd:YAG (1W/10Hz, 100mJ, long pulse, 15s, contact mode, without cooling); G4 – fluoride gel + Nd:YAG (1W/10Hz, 100mJ, long pulse, 15s, contact mode, without cooling). After the treatments, specimens were cycled through acidic challenges in hydrochloric acid (HCl, 20s, 6x/d) and artificial saliva for 5 days to induce erosion-like lesions, simulating the gastric juice. Wear depth, roughness and enamel step were assessed using confocal laser microscopy (OLS 4000). Data were analysed by Kruskal-Wallis test (α=5%). 

Results: For the wear depth, enamel step and roughness G4 presented the lowest values and differed from G2 and G3 (p<0.05). For the roughness, G3 showed the highest values differing statistically from the other groups (p<0.05).

Conclusions: The findings suggest that the Nd:YAG laser irradiation associated with acidulated phosphate fluoride gel was capable to inhibit the erosive process of the enamel. Financial Support: Capes (grant # 23038.040859/ 2008-95). Acknowledgment: Arotec S/A Indústria e Comércio.

Keywords: Enamel, Erosion, Lasers and Wear