RESUMO
This study evaluated the synergy of professional acidulated fluoride gel (APF) or fluoridated dentifrice application combined with Er,Cr:YSGG laser irradiation on the formation of CaF2 -like products (CaF2 ), in vitro. Thus, 272 bovine enamel slabs were randomly distributed among eight groups: G1: untreated enamel; G2: treated with fluoridated dentifrice (NaF, 1,100 µgF/g); G3: treated with acidulated phosphate fluoride gel (APF, 1.23% F(-) ); G4: irradiated with Er,Cr:YSGG laser at 8.5 J/cm(2) ; G5 and G6: combination of pre-irradiation with Er,Cr:YSGG followed by dentifrice or APF application, respectively; G7: combination of dentifrice application followed by Er,Cr:YSGG irradiation; G8: combination of APF application followed by Er,Cr:YSGG irradiation. After treatments, samples were evaluated by scanning electron microscopy, and the content of CaF2 was determined by an ion specific electrode. Both APF and dentifrice application promoted the formation of CaF2 on enamel, whereas Er,Cr:YSGG irradiation promoted an increase of roughness of the enamel, increasing the surface area. Laser irradiation before fluoridated products increased the content of CaF2 formed when compared to groups that APF or dentifrice were applied isolated. However, the content of CaF2 formed when irradiation was performed after APF or dentifrice was not statically significant when compared to the control groups. In conclusion, Er,Cr:YSGG laser increases the formation of CaF2 on enamel when the irradiation is performed before the application of APF or dentifrice. The association of laser with APF is most promissory for caries prevention because of the higher concentration of CaF2 formation and also the chemical changes promoted by laser irradiation demonstrated in literature.
Assuntos
Fluoreto de Cálcio/metabolismo , Fluoreto de Cálcio/efeitos da radiação , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/efeitos da radiação , Dentifrícios/farmacologia , Lasers de Estado Sólido , Terapia com Luz de Baixa Intensidade , Animais , Bovinos , Esmalte Dentário/ultraestrutura , Técnicas In Vitro , Terapia com Luz de Baixa Intensidade/métodos , Microscopia Eletrônica de Varredura , Resultado do TratamentoRESUMO
This study evaluated the effect of Er,Cr:YSGG laser irradiation and professional fluoride application on enamel demineralization and on fluoride formation and retention. In a blind in vitro study, 264 human enamel slabs were distributed into 8 groups: G1--untreated; G2--treated with acidulated phosphate fluoride gel (APF gel, 1.23% F) for 4 min; G3, G4 and G5--irradiated with Er,Cr:YSGG at 2.8, 5.6 and 8.5 J/cm2, respectively; G6, G7 and G8--preirradiated with Er,Cr:YSGG at 2.8, 5.6 and 8.5 J/cm2, respectively, and subjected to APF gel application. Twenty slabs of each group were submitted to a pH-cycling regimen, and enamel demineralization was evaluated in 10 slabs of each group. In the other 10 slabs, CaF2-like material was determined. To evaluate F formed, 10 additional slabs of each group, not subjected to the pH cycling, were submitted to analysis of CaF2-like material and fluorapatite, while the other 3 slabs of each group were evaluated by scanning electron microscopy. The F content was also measured in all pH-cycling solutions. Laser at 8.5 J/cm2 and APF treatment reduced enamel demineralization compared to the control (p < 0.05), but the combination of these treatments was not more efficient than their isolated effect. A higher concentration of retained CaF2-like material was found in laser groups followed by APF in comparison with the APF gel treatment group. The findings suggest that laser treatment at 8.5 J/cm2 was able to decrease hardness loss, even though no additive effect with APF was observed. In addition, laser treatment increased the formation and retention of CaF2 on dental enamel.
Assuntos
Cariostáticos/uso terapêutico , Esmalte Dentário/efeitos da radiação , Fluoretos/uso terapêutico , Lasers de Estado Sólido/uso terapêutico , Desmineralização do Dente/prevenção & controle , Fluoreto de Fosfato Acidulado/análise , Fluoreto de Fosfato Acidulado/uso terapêutico , Apatitas/análise , Apatitas/efeitos da radiação , Fluoreto de Cálcio/análise , Fluoreto de Cálcio/efeitos da radiação , Cariostáticos/análise , Esmalte Dentário/efeitos dos fármacos , Esmalte Dentário/ultraestrutura , Fluoretos/análise , Dureza , Humanos , Concentração de Íons de Hidrogênio , Eletrodos Seletivos de Íons , Microscopia Eletrônica de Varredura , Método Simples-Cego , Desmineralização do Dente/metabolismo , Remineralização DentáriaRESUMO
The dosimetry of beta radiation is a difficult process especially because of the low penetration of beta particles in matter. The dosemeter utilised for this kind of procedure needs to approximate an ideal point-like detector: it should be as thin as possible, and its area should be small. The thermoluminescence dosemeters (TLDs) meet with these requirement properties. The aim of this work was to study the dosimetric characteristics of different TLDs to verify the possibility of their use for the calibration of 90Sr+90Y plane applicators. The response reproducibility, calibration curves, TL response as a function of the source-detector distance, the transmission factors and the linearity of the sample response were obtained for several types of dosimetric pellets.
Assuntos
Partículas beta , Radioisótopos de Estrôncio/análise , Dosimetria Termoluminescente/instrumentação , Radioisótopos de Ítrio/análise , Fluoreto de Cálcio/efeitos da radiação , Sulfato de Cálcio/efeitos da radiação , Calibragem , Relação Dose-Resposta à Radiação , Disprósio/efeitos da radiação , Fluoretos/efeitos da radiação , Compostos de Lítio/efeitos da radiação , Manganês/efeitos da radiação , Reprodutibilidade dos TestesRESUMO
OBJECTIVE: The objective of this study was to evaluate the effect of Er:YAG laser on the formation of CaF(2), after the application of acidulated phosphate fluoride (APF), and its influence on the anti-cariogenic action in human dental enamel. BACKGROUND DATA: Er:YAG laser was designed to promote ablation of the enamel. However, the possibility of using this energy to increase the enamel's resistance to caries has hardly been explored, and neither has its interaction with the use of fluorides. MATERIALS AND METHODS: One hundred and twenty blocks of enamel were allocated to four groups of 30 blocks each: (1) C, control group; (2) Er:YAG, laser; (3) APF; and (4) Er:YAG+APF. Of these, 80 blocks were submitted to pH cycling for 14 days. In the other 40 blocks, fluoride (CaF(2)) was measured before cycling. After pH cycling, surface microhardness (SMH), microhardness in cross-section (converted to mineral contents % vol. min.), and fluoride after cycling (40 blocks) were also determined. RESULTS: SMH decreased in all groups. The control group showed the highest decrease, and Er:YAG+APF showed the lowest decrease (p < 0.05). Groups APF and Er:YAG showed the same results (p > 0.05). Mineral content at depths 10, 20, and 40 microm was lower in the control and Er:YAG groups, and higher in groups APF and Er:YAG+APF. CaF(2) (microgF/cm(2)) deposited before pH cycling was higher in the APF group when compared to the Er:YAG+APF group. Control and Er:YAG groups showed the lowest values (p > 0.05). CONCLUSION: It was concluded that Er:YAG laser influenced the deposition of CaF(2) on the enamel and showed a superficial anti-cariogenic action, but not in depth.