Correlação da permeabilidade com a resistência de união na dentina humana desproteinizada utilizando tratamentos de laser e fosfato de cálcio
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Data
2018-12-14
Autores
Andrade, Danilo de Souza [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
As restaurações a base de materiais resinosos tiveram um grande desenvolvimento, entretanto a durabilidade da interface adesiva ao substrato dental ainda é comprometida pela permeabilidade dentinária e pela degradação da camada hibrida. O objetivo desse estudo foi avaliar, in vitro, tratamentos que reduzem a permeabilidade dentinária, como aplicação de produto dessensibilizante à base de fosfato de cálcio e processo assistido a laser, e correlacionar essa redução de permeabilidade com a resistência de união a dentina. Sessenta discos de dentina de molares humanos com 6 mm de diâmetro e 1,5 mm de altura foram utilizados. Foi realizado desproteinização na superfície dentinária oclusal de todas as amostras. As amostras foram divididas em seis grupos (n=10) conforme os tratamentos sendo: A – Adesivo (Single Bond Universal – 3M ESPE); LA – Laser de Nd:YAG + Adesivo; AL - Adesivo + Laser Nd:YAG; FA – Fosfato de Cálcio + Adesivo; FLA – Fosfato de Cálcio + Laser Nd:YAG + Adesivo e FAL – Fosfato de Cálcio + Adesivo + Laser Nd:YAG. O percentual das permeabilidades inicial e final (após tratamento) foi calculado a partir da permeabilidade máxima. Os grupos foram comparados em cada momento da avalição da permeabilidade (inicial e final). Para o teste de resistência de união (RU) as amostras foram restauradas com resina composta (Z350 – 3M ESPE) e submetidas ao envelhecimento termomecânico (5.000 ciclos térmicos e 120.000 mecânicos), posteriormente foram confeccionados palitos para o teste de microtração. Os resultados para a permeabilidade dentinária e desvio padrão foram (médias percentuais %): iniciais A: 63,18 (±15,82); FA: 72,87 (±17,48); LA: 78,42 (±15,92); FLA: 72,64 (±24,28); AL: 74,96 (±16,86) ; FAL: 71,60 (±15,33) e as médias percentuais após os tratamentos: A: 29,99 (±16,38); FA: 34,42 (±18,60); LA: 35,13 (±20,61); FLA: 26,70 (±11,44); AL: 20,20 (±6,32) e FAL: 23,85 (±12,30). Os resultados e o desvio padrão para o teste de RU (em Mpa) foram: A 35,28 (±4,18); FA 32,17(±3,10); LA 39,19 (±4,58); FLA 36,06 (±2,75); AL 34,34 (±3,63) e FAL 35,14 (±2,40). Os dados foram submetidos ao teste de ANOVA, para a permeabilidade, observou-se uma redução estatisticamente significante para todos os tratamentos (p=0), no entanto não foram observadas diferenças na redução da permeabilidade entre os tratamentos (p=0,318125), para a RU a presença de fosfato não demonstrou diferença estatisticamente significante (p>0,05), no entanto para o fator tratamento houve diferença entre os grupos (p<0,05), o teste de Tukey 5% mostrou que os grupos LA e FLA apresentaram valores superiores estatisticamente os demais. No teste de correlação de Pearson foi constado que a correlação entre RU e permeabilidade foi insignificante (r= - 0,0581). O presente estudo concluiu que todos os tratamentos foram efetivos para a redução da permeabilidade. A resistência de união foi afetada pelos tratamentos. A correlação entre RU e permeabilidade foi desprezível.
The restorations based on aesthetic materials had a great development, however the durability of the adhesive interface to the dental substrate is still compromised by the dentin permeability and the degradation of the hybrid layer. The aim of this study was to evaluate, in vitro, treatments that reduce dentin permeability, such as the application of desensitizing product based on calcium phosphate and laser assisted process, and to correlate this reduction of permeability with bond strength to dentin. Sixty discs of dentin from human molars 6 mm in diameter and 1.5 mm in height were used. Deproteinization was performed on the occlusal dentin surface of all samples. The samples were divided into six groups (n = 10) according to the treatments: A – Adhesive (Single Bond Universal – 3M ESPE); LA - Nd: YAG Laser + Adhesive; AL - Adhesive + Laser Nd: YAG; FA - Calcium Phosphate + Adhesive; FLA - Calcium Phosphate + Nd: YAG Laser + Adhesive and FAL - Calcium Phosphate + Adhesive + Nd: YAG Laser. The percentage of the initial and final permeabilities (after treatment) was calculated from the maximum permeability. The groups were compared to each other at each moment of the permeability assessment (initial and final). For the bond strength test the samples were restored with composite resin (Z350 - 3M ESPE) and subjected to thermomechanical aging (5,000 thermal cycles and 120,000 mechanical), later sticks were made for the microtensile test. The results for dentin permeability were: (means % and sd): initial A: 63.18 (± 15.82); FA: 72.87 (± 17.48); LA: 78.42 (± 15.92); FLA: 72.64 (± 24.28); AL: 74.96 (± 16.86); FAL: 71.60 (± 15.33) and the mean percentages after treatments: A: 29.99 (± 16.38); FA: 34.42 (ñ 18.60); LA: 35.13 (± 20.61); FLA: 26.70 (± 11.44); AL: 20.20 (± 6.32) and FAL: 23.85 (± 12.30). The results and standard deviation for the bond strength test (in Mpa) were: A 35.28 (± 4.18); FA 32.17 (± 3.10); LA 39.19 (± 4.58); FLA 36.06 (± 2.75); AL 34.34 (± 3.63) and FAL 35.14 (± 2.40). The results were submitted to ANOVA, a statistically significant reduction in permeability was observed for all treatments (p = 0), however, no differences were observed in the reduction of permeability between treatments (p = 0.318125), the presence of phosphate did not show a statistically significant difference (p> 0.05), however for the treatment factor there was difference between the groups (p <0.05), so Tukey 5% was applied, the LA and FLA groups presented values statistically superior to the others. Pearson's correlation test showed that there was a insignificant correlation (r=- 0,0581). The present study concluded that all treatments were effective for the reduction of permeability. The bond strength was affected by the treatments. A correlation between the permeability and the bond strength can not be observed.
The restorations based on aesthetic materials had a great development, however the durability of the adhesive interface to the dental substrate is still compromised by the dentin permeability and the degradation of the hybrid layer. The aim of this study was to evaluate, in vitro, treatments that reduce dentin permeability, such as the application of desensitizing product based on calcium phosphate and laser assisted process, and to correlate this reduction of permeability with bond strength to dentin. Sixty discs of dentin from human molars 6 mm in diameter and 1.5 mm in height were used. Deproteinization was performed on the occlusal dentin surface of all samples. The samples were divided into six groups (n = 10) according to the treatments: A – Adhesive (Single Bond Universal – 3M ESPE); LA - Nd: YAG Laser + Adhesive; AL - Adhesive + Laser Nd: YAG; FA - Calcium Phosphate + Adhesive; FLA - Calcium Phosphate + Nd: YAG Laser + Adhesive and FAL - Calcium Phosphate + Adhesive + Nd: YAG Laser. The percentage of the initial and final permeabilities (after treatment) was calculated from the maximum permeability. The groups were compared to each other at each moment of the permeability assessment (initial and final). For the bond strength test the samples were restored with composite resin (Z350 - 3M ESPE) and subjected to thermomechanical aging (5,000 thermal cycles and 120,000 mechanical), later sticks were made for the microtensile test. The results for dentin permeability were: (means % and sd): initial A: 63.18 (± 15.82); FA: 72.87 (± 17.48); LA: 78.42 (± 15.92); FLA: 72.64 (± 24.28); AL: 74.96 (± 16.86); FAL: 71.60 (± 15.33) and the mean percentages after treatments: A: 29.99 (± 16.38); FA: 34.42 (ñ 18.60); LA: 35.13 (± 20.61); FLA: 26.70 (± 11.44); AL: 20.20 (± 6.32) and FAL: 23.85 (± 12.30). The results and standard deviation for the bond strength test (in Mpa) were: A 35.28 (± 4.18); FA 32.17 (± 3.10); LA 39.19 (± 4.58); FLA 36.06 (± 2.75); AL 34.34 (± 3.63) and FAL 35.14 (± 2.40). The results were submitted to ANOVA, a statistically significant reduction in permeability was observed for all treatments (p = 0), however, no differences were observed in the reduction of permeability between treatments (p = 0.318125), the presence of phosphate did not show a statistically significant difference (p> 0.05), however for the treatment factor there was difference between the groups (p <0.05), so Tukey 5% was applied, the LA and FLA groups presented values statistically superior to the others. Pearson's correlation test showed that there was a insignificant correlation (r=- 0,0581). The present study concluded that all treatments were effective for the reduction of permeability. The bond strength was affected by the treatments. A correlation between the permeability and the bond strength can not be observed.
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Palavras-chave
Permeabilidade da Dentina, Fosfato de Cálcio, Laser de Nd:YAG, Hipoclorito de Sódio, Resistência de União, Dentin Permeability, Calcium Phosphate, Nd:YAG Laser, Sodium Hypochlorite, Bond Strenght