Effect of Thermocycling on the Compressive Strength of Implant-Abutment Systems

Objective: The aim of this study was to evaluate the efect of thermocycling on the ultimate compressive strength of implant-abutment systems under oblique loading.   

Method: Thirty two dental implants for each type of connection, external (EH) or internal (IH) hexagon, were individually included in PVC cylinders using epoxy resin. Mini conical (MC) and UCLA abutments were connected to the implants (30 N.cm) and divided into two groups (n=16): 1-without thermocycling (Control-C) and 2-thermocycled specimens (TC). Specimens were subjected to 10,000 cycles with temperatures ranging between 5.0 and 55ºC and a dwell time of 30s for each temperature. The specimens were submitted to compressive mechanical loading (1.0 mm/min, 5.0 kN) applied at 135º to the long axis of the abutment using a electromechanical testing machine EMIC DL 2000. Kruskal-Wallis and Student-Newman-Keuls tests were used for statistical analysis (a=0.05).

Result: The data of ultimate compressive strength (N) were EHMCC=581.48, EHMCTC=542.47 EHUCLAC=485.48, EHUCLATC=483.35, IHMCC=655.35, IHMCTC= 650.57, IHUCLAC=528.41, IHUCLATC=543.40. No statistically significant differences were found among the thermocycled and controls groups, as well as between the type of external abutment used (MC or UCLA). However, for internal hex, statistically significant (p<0,05) difference was found between the UCLA and MC abutments.

Conclusion: Regardless of abutment and/or connection type, thermocycling did not detrimentally affected the values of ultimate compressive strength of the implant-abutment systems.