Aim:
The aim of this study was to assess the effect of acidic beverages on color stability and microhardness of various esthetic restorative materials.
Materials and Methods:
A total of 60 samples were included in the present study. Group I: Microhybrid composite resin, Group II: Nanoceramic, Group III: ORMOCER (Organically Modified Ceramics). 10 mm internal diameter and 5 mm depth of cylindrical aluminum mold of were utilized to prepare the samples. All the esthetic restorative samples were submerged for 10 min in 25 ml of acidic drink (Coca-Cola) each day up to 15 days. Vickers diamond intender was used to measure the microhardness of each sample. These values were calculated with baseline, 7th, and 15th days for final microhardness values.
Results:
The mean surface microhardness of 63.20 ± 0.46 was shown by Group III which was slightly more than that in Group II (60.08 ± 0.34) and Group I (58.10 ± 1.76). Analysis of covariance did not show any statistically significant difference between the groups. The samples in Group I showed the highest reduction in surface microhardness value after immersion into acidic drink, followed by Group II and Group III on 7th day and 15th day. A statistically significant difference (P < 0.001) was found on the 7th day.
Conclusion:
The present study concludes that the Organically Modified Ceramics esthetic restorative material showed the finest behavior after being dipped in the acidic drink followed next by Nanoceramic and Microhybrid composite resin.
Aim:
The aim of the study was to investigate whether the surface geometry or topography of implant abutments affects the retentive strength of prosthesis cemented with zinc phosphate on standard machined, sandblasted, and grooved implant abutments and to compare the results between them.
Materials and Methods:
Fifteen similarly shaped implant abutments (MDcpk61; MIS Implant Technologies Ltd.,) (height 6.0 mm and 6-degree taper) were divided into three groups (n = 05): Group I – standard machined abutments without grooves, Group II – sandblasted abutments (same as Group I but sandblasted with 50 μ aluminum oxide), and Group III – abutment with prefabricated circumferential grooves. Further in these groups of 15 abutments, 5 abutments each are to be taken to check the retentive force of zinc phosphate cement. Fifteen identical cast copings was prepared to fit all 15 abutments. The castings will be cemented to each group of abutments with an above-mentioned luting agent. After thermal cycling and storage for 6 days in a water bath, a retention test is to be done with a tensile testing machine (Instron) (5 mm/min) and retentive forces will be recorded. Data will be subjected to one-way ANOVA test and Student's t-test.
Results:
For zinc phosphate cement, F = 30.53 (>3.59 for P = 0.05) shows a statistically significant difference between all the three groups.
Conclusion:
Circumferential grooves on implant abutments give better retention when compared with standard machined (plain) and sandblasted abutments despite marked difference.
Clinical Significance:
Retention of restoration depends on the surface of the abutment as well as the luting agents used. Incorporation of retentive grooves can enhance retention of prosthesis, especially in situation of short abutments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.