Effects of coronal implant neck flutes on early peri-implant osteogenesis and stability

PURPOSE: Limited research has investigated how implant neck flute design influences early peri-implant osteogenesis and implant stability in vivo. This study evaluated the effects of different neck flute designs on peri-implant bone healing and osseointegration in rat tibiae. METHODS: Three types of custom-made implants (13 mm total length, 8 mm screw part, 2 mm diameter) were used: Type A (4 coronal flutes, 1.50 mm length, 0.2 mm notch radius, 0.20 mm depth), Type B (4 coronal flutes, 1.50 mm length, 0.5 mm notch radius, 0.20 mm depth), and Type C (no coronal flutes). The implants were bilaterally inserted into the tibiae of 21 male Wistar rats. After 4 weeks of healing, removal torque testing, micro-computed tomography, histological, and histomorphometric assessments were performed to evaluate osseointegration and the quality and quantity of the peri-implant bone. The assessments included the relative gray value (RGV; water = 0, implant = 100), bone-to-implant contact (BIC), and peri-implant bone volume/tissue volume (BV/TV). RESULTS: Removal torque tests demonstrated significant differences among implant types, with Type A and Type B implants exhibiting higher values than Type C. The RGV revealed no significant differences among groups. Histomorphometric analysis revealed no significant differences among groups. CONCLUSION: The coronal flute design was associated with improved implant stability and osseointegration compared to non-fluted implants. This suggests that neck flute designs may enhance early peri-implant osseointegration and stability.