A comparative study of microstrain around three-morse taper implants with machined and plastic copings under axial loading

Aim : To evaluate the occurrence of microstrain around morse taper implants in straight configuration under axial load in a cast monoblock framework.
Methods: Three implants were inserted in a polyurethane block and microunit abutments were installed on the implants with 20 Ncm torque. Plastic and machined copings were adapted on the preset waxing to fabricate the framework (n=5). Four strain gauges were attached on the upper surface of the block and then each framework was tightened on the abutments and a vertical load of 30 kg was applied to five points of the framework.
Results: The data obtained in the strain gauge analysis were subjected to two-way ANOVA and Tukey′s test (α=0.05). There was statistically significant difference (p=0.0222) for the factor application point and the mean microstrain values were: application point B 402,04με, point A 401.21με, point E 390.44με , point D 341.76με and point C 309.19 με.
Conclusions : There was no microstrain difference between plastic and machined copings during axial loading. Difference in the application point was observed, but remained within bone physiological limits.

Keywords
dental implant, fixed prosthesis, axial load, strain gauge, morse taper