A comparative study of deformation in hexagonal and star-shaped implant screwdriver heads

Dental implants are a popular and effective solution for replacing missing teeth. However, there are challenges such as screw loosening and component failure. This deformation can impact torque application and screw retention. While research has focused on implant system longevity, there is limited investigation into how different screwdriver head designs, particularly hexagonal and star-shaped, perform under repeated opening and closing cycles, which are crucial for long-term implant stability. The study compared the deformation characteristics of hexagonal and star-shaped implant screwdriver heads after multiple opening and closing cycles.

In this in vitro experimental study, abutments were placed on two implant systems mounted in die stone and torqued to 25 N/cm according to the manufacturer's recommendations, using 12 screwdrivers (n = six for each implant). The screwdriver heads underwent examination under a stereomicroscope at 50x magnification. Subsequently, the outline and deformation of the screwdriver head after 0, 50, 100, 200, and 300 opening and closing cycles were analyzed using AutoCAD software. The changes in the surface area of hexagonal and star-shaped driver heads after different cycles were statistically evaluated using SPSS 24 (α = 0.05).

The investigation revealed a reduction in the surface area of both hexagonal and star-shaped driver heads with an increase in the frequency of cycles. Notably, following all cycles, except 0-50 and 50-100, the alterations in the surface area of the star-shaped driver head were significantly greater than those observed in the hexagonal driver head (P < 0.001).

The study shows that the star-shaped driver head deformed more than the hexagonal one, especially in cycles exceeding 100.