Effect of different modifications in dental implant-abutment body on retention of cemented implant restorations

Abstract

Introduction: Fixed implant-based prostheses are one of the most common treatments in dentistry. The connection of dental prostheses to implants is performed by means of abutment and can be screwed or cemented. The aim of the present study was to investigate the Effect of different modifications in dental implant-abutment body on retention of cemented implant restorations

Materials and Methods: For this study, 64 direct abutments of DIO system with a length of 5.5 mm, a diameter of 4.5 mm and a gingival height of 1 mm were used. After making standard castings on the abutments, the samples were divided into 8 groups. In the first and second groups, a horizontal hole with a diameter of 1 mm was made at a distance of 1 mm below the occlusal edge of the abutment, and in the third and fourth groups, two holes with a diameter of 1 mm were made at an angle of 180 degrees to each other and 1 mm below the occlusal edge. The abutments of the fifth and sixth groups were sandblasted and the abutments of the seventh and eighth groups as the control group remained unchanged. Then Temp Bond NE Cement were used to cement 4 groups and zinc phosphate cement were used to cement 4 other groups according to the manufacturer's instructions. After that, the samples were placed for 24 hours at 100% humidity and 37 ° C. Then the samples were evaluated by pull out test with a crosshead speed of 0.5 mm / min by a universal testing machine and the force required to remove the couplings was measured on a Newton scale. Data obtained from tests by using descriptive statistics (mean ± standard deviation) were described. The normality of the data was assessed by Kolmogorov-Smirnov test. The data were then analyzed using Twoway Anova test. Statistical analysis was performed by SPSS 20 software and the significance level of the test was P <0.05. Results: The rate of retention in temporary cements with control abutments, 1 hole, 2 holes and sandblast was equal to 60/13, 58/35, 57/45 and 145/70 Newton, respectively. The retention in permanent cements with the mentioned abutments was 140, 170/91, 190/87 and 465/31 Newton, respectively. By creating a hole, the amount of retention increased in the group of permanent cements and decreased in the group of temporary cements. But there was no statistically significant difference between the amount of retention and the creation of holes (One hole P=0.993 and two holes P=0.978) in the group of temporary cements and (One hole P=0.212 and two holes P=0.117) in the group of permanent cements. and only a statistically significant difference was observed between the amount of retention in sandblasted abutments with other groups. (P=0.001) Conclusions: According to the results obtained in this study, it can be concluded that making microscopic changes (sandblasting) more than making macroscopic changes (making holes) increase retention rate in both temporary and permanent cements. By making some geometric changes in the abutments, despite providing a sufficient retention in the level of permanent cements, clinically we can use the advantages of temporary cements.