Influence of abutment surface roughness on retention of implant supported crowns luted with different provisional cements
Dr. Hafezeqoran A.,1 Dr. Seyedan K.,2 Dr. Morshedi K.2
1Post graduate student, Department of Prosthodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 2Assistant Professor, Department of Prosthodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Background & Aim: Easy retrieval is the main advantage of using provisional luting agents for cementation of cemented type implant supported prosthesis. However, adequate retention is also required. The purpose of this study was to compare the retention status of implant supported single restorations with different combinations of implant abutment surface conditions and provisional luting agents.
Materials & Methods: This experimental study was conducted using twenty prepable titanium implant abutments (Biohorizons) 8mm in height. They were placed in implant analogs and torqued to 30 Ncm. Implant analogs were mounted in self cured acrylic resin blocks using surveyor. After fabrication of crowns for each abutment, provisional luting agents, such as TempBond, Dycal and TempBond NE were used to secure the crowns over the respective abutments. All specimens were stored in 100% humidity for 48 hours at 37°C prior to testing. Each crowns was pulled from the abutment with a 500 kg load cell in a universal testing machine at a crosshead speed of 0.5 cm/minute, and tensile strength was recorded (N). The specimens were then divided into 2 groups. Ten samples were abraded with 50 μm aluminum oxide and the other 10 were roughened by using a medium roughness diamond rotary cutting instrument. Temporary cements were used and tensile strength tests were performed similarly for all samples. Data were analyzed using paired T-Test and two-way ANOVA.
Results: Tensile strength was significantly higher for Dycal (26.01 ± 3.53) than TempBond NE and TempBond. The result of the two-way ANOVA indicated that a significant interaction existed between the provisional luting agents and the surface conditions. TempBond and TempBond NE showed significantly higher tensile strength when combined with airborne particle abraded surface or roughened surface with diamond burs. However no difference was detected in tensile strength for Dycal in different combinations.
Conclusion: The surface modification of an implant abutment by airborne particle abrasion or diamond rotary cutting instrument may be an effective method to increase the retention of a crown when TempBond NE or TempBond was used. However, this process did not improve the retention of crown which was secured with Dycal.
Key words: Implant supported prosthesis - Provisional cement - Air abrasion - Retention.
Corresponding Author: Dr. Hafezeqoran A., Department of Prosthodontics, Dental School, Shahid Beheshti University of Medical Sciences, Tehran, Iran.