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| Author(s): |
Walter Raucci Neto
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Ribeirão Preto. |
| Institution: | Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC) |
| Defense date: | 2013-07-31 |
| Examining board members: |
Regina Guenka Palma Dibb;
Luciano Bachmann;
Marilia Afonso Rabelo Buzalaf;
Alexandra Mussolino de Queiroz;
Yara Teresinha Corrêa Silva Sousa
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| Advisor: | Regina Guenka Palma Dibb |
| Abstract | |
The aim of this study was to evaluated the effect of Nd:YAG laser irradiation alone or combined to fluoride on the occlusal surface of primary and permanent teeth. 52 children (age 7.6 ± 1.4 years) were selected to this study. The four quadrants in the subjects were randomly assigned to receive the controls and experimental treatments. 1st primary molar was the negative control, Acidulated Phosphate Fluoride (APF - positive control 1) or fluoride varnish (FV - positive control 2). 2nd primary molar and 1st permanent molar received resin sealant, laser irradiation (100mJ/5Hz-0.5W), APF + laser irradiation or FV + laser irradiation. Patients were followed-up to 24 months to evaluate the presence of white-spot lesions and/or caries cavities by three calibrated observers (k=0.92). Primary teeth that naturally exfoliated (in 1 year period) were collected, storage in deionized water and the surface area submitted to scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR) and electron spectroscopy for chemical analysis (EDS). The occlusal subsurface was analyzed by cross-section Knoop microhardness and light microscopy to evaluate the caries lesions status. 35 patients completed the 24 months evaluation period. The clinical data were submitted to Cochran Q (α=0.1%) and Tukey (α=5%) tests. Primary teeth clinical results: laser alone group presented lower caries formation compared to negative control group (p<0.05). However the laser preventive effect decreased after 12 months. Permanent teeth clinical results: the sealant group presented lower caries formation compared to the remaining groups (p<0.05). However the sealant preventive effect decreased after 12 months. FTIR data were analyzed by one-way ANOVA (α=0.1%) and Tukey (α=5%) tests. Cross-section Knoop microhardness and light microscopy data were analyzed by Kruskall-Wallis test (α=0.1%) followed by Tukey test (α=5%). The images obtained with SEM and the percentage of elements calcium, phosphorus and fluoride were qualitatively evaluated by comparing the irradiated area with the control surface. FTIR analysis showed lower concentration of CO3 on lased group (0.98±0.06). Higher [ ] of CO3 were observed on negative control group (1.47±0.31) and laser combined with fluoride (1.51±0.29). SEM analysis revealed that control samples showed a slightly smoother surface compared to lased groups. The EDS analysis revealed no difference in the Ca, P and F % among all studies groups. For microhardness was observed that sealant and laser irradiation alone (262.44±22.69) showed significant higher values compared to control - group (128.35±25.19). For light microscopy, it was observed significant lower caries lesion formation in laser alone (5.35%±5.38) and laser combined to APF (10.35% ±0.88) to the negative control group (72.56%±12.86). Within the limitations of this study it can be concluded that Nd:YAG laser irradiation over one year period for primary dentition and over 9 months for permanent dentition, regardless fluoride association, modified enamel surface to successfully inhibits caries formation. (AU) | |
| FAPESP's process: | 09/07141-3 - Clinical evaluation of the effect of nd: YAG laser in the prevention of oclusal caries in the deciduous and permanent dentition |
| Grantee: | Walter Raucci Neto |
| Support Opportunities: | Scholarships in Brazil - Doctorate |