Beverages immersion effect on compomer and giomer microhardness
The aim of this study was to evaluate and compare the beverages effect on micro-hardness of compomer and giomer direct restorative materials in comparison with mineral water. Two types of direct restorative materials of A3 shade were selected for this study: Compomer (Dyract extra Dentsply, Yourk , PA, USA) and Giomer (Beautiful-II, Shofu, San Marcos, CA, USA). Thirty specimens were prepared from each restorative material (total number of specimens were 60). Each specimen was prepared by compressing sufficient amount of material into a mould of 6 mm in diameter and 2 mm in thickness by two glass slides with acetate celluloid strip in between and curing the specimen by making the curing tip in intimate contact with the acetate celluloid strips covering the giomer top surface with LED Woodpacker light curing unit for 20s with an LED of output 600 mW/cm2 while compomer was light cured similarly but for 40s on each surface of the specimen (top and bottom). The thirty specimens of each group were sub divided into three subgroups (n=10) according to the 3 types of beverages being selected in this study. The top and bottom surfaces were divided into two halfs: 1st half was subjected to microhardness testing before immersion, while microhardness testing was performed on the 2nd half after immersion in beverages. pH values were recorded for each beverage solution with pH meter (METTLER TOLEDO, CANADA). Vickers micro hardness testing was performed with microhardness tester (Micro hardness tester FM-800, FUTURE-TECH, Japan) at 300g load and 15 seconds according to ISO 4049 for both top and bottom surfaces by making three indentations and considering the mean microhardness value for each surface to be the Vickers hardness number for that surface. Three types of beverages were used in the study (Cola, coffee and mineral water). Specimens were kept in distilled water for 24 hours before immersing them in any beverage. The specimens were alternately immersed in glass containers containing 25 ml of each media for 2 minutes in three cycles. The same protocol was done for 28 days consecutively. The beverages (immersion solutions) were refreshed daily to maintain the pH level. After the immersion sequence was completed, the compomer and giomer specimens were rinsed in distilled water, blotted dry and subjected to surface microhardness testing. Data was statistically analysed by calculating the differences between the values before and after immersion of the sixty specimens for their tops and bottoms with one way ANOVA at 5% level of significance. Statistical analysis of the data revealed that, there was a statistically significant difference between the 6 groups being tested in their differences before and after beverage immersion (ANOVA, p≤ 0.05) for their tops while there was a statistically insignificant difference between the 6 groups (ANOVA, p≥ 0.05) for their bottoms. The pH values of the immersion solutions were recorded as follows: aerated beverage (Coco-Cola) (2.665); coffee (Nescafé classic 3in1) (5.549); and mineral water (Mai Dubai) (7.2). In general, immersion in any beverage resulted in reduced microhardness values of both restorative materials tops and bottoms. Water immersion resulted in minimal microhardness differences values for both restorative materials tops and bottoms. Cola immersion resulted in highest microhardness reduction for giomer tops and bottoms while coffee resulted in highest microhardness reduction for compomer tops and bottoms. Clinical significance: Beverages contain chemical components and their acidic nature or water content might affect the hardness of direct restorative materials that might lead to the degradation at the matrix/filler interface by acid attack and consequently a negative effect on the general performance of the affected restoration in oral service.
|Journal||Journal of International Dental and Medical Research|
|Publisher||Ektodermal Displazi Grubu - Türkiye|