ABSTRACT
O objetivo desse estudo foi avaliar a influência da técnica de preparo cavitário e de materiais restauradores contendo flúor na prevenção da secundária. Dentes humanos foram seccionados em 72 blocos e distribuídos em dois grupos. Cavidades com 1,6 mm de diâmetro foram preparadas com pontas diamantadas ou laser de Er:YAG laser (6 Hz, 300 mJ, 47 J.cm elevado a 2). Cada grupo foi dividido em três subgrupos e restaurados com cimento de ionômero de vidro, ionômero de vidro modificado por resina ou uma resina composta. Os espécimes foram termociclados e submetidos a ciclagem de pH. As lesões de cárie artificial foram ranqueadas utilizando uma escala ordinal por inspeção visual. Os testes de Kruskal-Wallis e Dunn (α = 0,05) não demonstraram diferenças no desenvolvimento de lesões entre as cavidades resturadas com o mesmo material e preparadas com pontas diamantadas ou laser de Er:YAG laser. O laser de Er:YAG utilizado para o preparo cavitário com 6 Hz, 300 mJ, 47 J.cm elevado a 2 não demonstrou a habilidade de garantir maior ácido resistência aos preparo.
The objective of this study was to evaluate the influence of the cavity preparation technique and fluoride-containing restorative materials on the prevention of the secondary caries. Human teeth were sectioned into 72 blocks and distributed into 2 groups. Cavities measuring 1.6 mm were performed with diamond burs or Er:YAG laser (6 Hz, 300 mJ, 47 J.cm to the -2 power). Each group was divided into 3 sub-groups, and restored with a glass-ionomer cement, resinmodified glass-ionomer, or composite resin. The specimens were thermal cycled and submitted to pH cycling. Artificial caries were scored using an ordinal scale based on visual inspection. Kruskal-Wallis and Dunn test ((α = 0,05) showed no differences in the caries lesion development between the cavities restored with the same material and prepared with diamond burs or Er:YAG laser. The Er:YAG laser used for cavity preparation used with 6 Hz, 300 mJ, 47 J.cm to the -2 power did not show the ability to guarantee significantly more acid-resistance against acid challenge.
Subject(s)
Statistics, Nonparametric , Composite Resins , Dental Caries , Dental Cavity Preparation , Lasers, Solid-State , Fluorine , Glass Ionomer CementsABSTRACT
OBJECTIVES: This study evaluated the effects of light exposure through simulated indirect ceramic restorations (SICR) on hardness (KHN) of dual-cured resin cements (RCs), immediately after light-activation and 24 h later. MATERIAL AND METHODS: Three dual-cured RCs were evaluated: Eco-Link (Ivoclar Vivadent), Rely X ARC (3M ESPE), and Panavia F (Kuraray Medical Inc.). The RCs were manipulated in accordance to the manufacturers' instructions and were placed into cylindrical acrylic matrixes (1-mm-thick and 4-mm diameter). The RC light-activation (Optilux 501; Demetron Kerr) was performed through a glass slide for 120 s (control group), or through 2-mm or 4-mm thick SICRs (IPS Empress II; Ivoclar Vivadent). The specimens were submitted to KHN analysis immediately and 24 h after light-activation. The data obtained at the 2 evaluation intervals were submitted to 2-way ANOVA repeated measures and post-hoc Tukey's test (pre-set alpha of 5 percent). RESULTS: Lower KHN was observed when light-activation was performed through SICRs for Eco-Link at all evaluation intervals and for Rely X ARC 24 h later. For Panavia F, no significant difference in KHN was observed between control and experimental groups, regardless of evaluation interval. Most groups exhibited higher KHN after 24 h than immediately after light-activation, with the exception of Rely X ARC light-activated through SICR, as no significant difference in KHN was found between evaluation intervals. CONCLUSIONS: Light overexposure did not compensate for light intensity attenuation due to the presence of SICR when Rely X and Eco-Link were used. Although hardness of such RCs increased over a 24-h interval, the RCs subjected to light overexposure did not reach the hardness values exhibited after direct light exposure.
Subject(s)
Ceramics/radiation effects , Light-Curing of Dental Adhesives/methods , Resin Cements/radiation effects , Self-Curing of Dental Resins/methods , Analysis of Variance , Bisphenol A-Glycidyl Methacrylate/chemistry , Bisphenol A-Glycidyl Methacrylate/radiation effects , Ceramics/chemistry , Hardness Tests , Materials Testing , Polyethylene Glycols/chemistry , Polyethylene Glycols/radiation effects , Polymerization/radiation effects , Polymethacrylic Acids/chemistry , Polymethacrylic Acids/radiation effects , Resin Cements/chemistry , Surface Properties/radiation effects , Time FactorsABSTRACT
Trabalhos da literatura demonstram a capacidade dos lasers de alta potência utilizados com parâmetros subablativos tornar o esmalte dental ácido-resistente, porém não se sabe se o calor residual resultante da irradiação pode também tornar o esmalte adjacente às paredes mais ácido resistentes. Este estudo avaliou in situ a influência do preparo cavitário utilizando o laser de Er,Cr:YSGG e materiais restauradores contendo flúor na prevenção de lesões de cárie. Terceiros molares humanos foram seccionados em 30 blocos de esmalte dental e distribuídos em dois grupos para o preparo de cavidades (1,6 rnm0) com pontas diamantadas ou com o laser de Er,Cr:YSGG (20 Hz, 4 W, 22 J/cm2). Depois disso, foram divididos em três sub-grupos e restaurados com ionômero de vidro, ionômero de vidro modificado por resina ou resina composta. Os blocos foram fixados em dispositivos intra-orais, utilizados por voluntários durante 21 dias e tratados com sacarose 20% oito vezes por dia. As lesôes cariosas foram avaliadas pelo ensaio de microdureza Knoop superficial (KHN) a 100 11m da margem do preparo, considerando na ANOVA dois fatores "Preparo" e "Material" e a interação de ambos, seguido pelo teste T ukey. Em seguida, os blocos foram seccionados e a microdureza subsuperficial foi avaliada a 100 11m da margem da cavidade nas profundidades de 30, 60, 90, 120, 150 e 200 11m. Considerou-se na Análise de variância três fatores "Profundidade", "Preparo" e "Material", seguido pelo teste Tukey. Observou-se menor desenvolvimento de lesões cariosas ao redor das cavidades preparadas com laser do que em torno das cavidades preparadas com pontas diamantadas. Houve efeito sinérgico cariostático subsuperficial entre o laser de Er,Cr:YSGG e o híbrido de ionômero de vidro e resina composta.
Severa I researches in the literature show the potential of high intensity lasers used in subablative parameters to modify the dental enamel providing more acid resistance. However, their ability to improve acid resistance during cavity preparation is unknown. The influence of the cavity preparation technique and the types of restorative materiais containing fluorides in the prevention of in situ development of secondary caries lesions were evaluated. Human teeth were sectioned in 30 blocks and distributed into 2 groups. Cavity preparations measuring 1.6 mm were performed with diamond burs or Er,Cr:YSGG laser (20 Hz, 4 W, 22 J/cm2). After that, each group was divided in 3 sub-groups that were restored using a glass-ionomer cement, a resin-modified glass-ionomer or a composite resin. The restored slabs were fixed in palatal intra-oral appliances worn in situ for human volunteers, which dropped a 20% sucrose's solution 8 times a day. After 21 days they were removed and a superficial microhardness analysis were done (KHN) 100 11m from cavity margin. The data were evaluated by 2-way ANOVA and T ukey considering the factors "Preparation" and "Material': After that, enamel slabs were sectioned and subsuperficial microhardness evaluation were performed at 30, 60, 90, 120, 150 e 200 11m from surface. The data were evaluated by 3-way ANOVA and Tukey considering the factors "Subsurface", "Preparation" and "Material': Less caries development were observed around the cavities prepared with the Er,Cr:YSGG laser. There were a synergistic effect between the Er,Cr:YSGG laser and the resin-modified glass-ionomer.