Evaluation of the effect of self-cutting and nonself-cutting thread designed implant with different thread depth on variable insertion torques: An histomorphometric analysis in rabbits.

Purpose: To evaluate of the effect of self-cutting and nonself-cutting thread designed implant with different thread depth on variable insertion torques. To evaluate the bone volume (BV) and bone to implant contact (BIC) in these variables MATERIALS AND METHODS: Mainly two thread design, V-shaped thread which is self-cutting and power thread design, which is nonself-cutting implants were considered for this study with a variation in thread depth of 0.4 and 0.6 mm for both the designs, respectively. A total of 32 CAD designed machined surface implant prototypes were manufactured of 4 mm in diameter and 8 mm in length were made, which were machined surfaced, which was placed in the femur of 16 New Zealand white rabbits. These were categorized under 2 groups; Group 1 and Group 2 with insertion torques of <30 and >50 Ncm, respectively. After 4 weeks of healing, rabbits were sacrificed and histomophometric and histologic analyses were done to evaluate the bone response.

Results: Significantly, more BIC was recorded for high torque implants compared with low torque in power-shaped thread design (P value = .01*). BV for new bone formation was statistically significant for V-shaped thread design in high torque when compared with low torque (P value = .02*).

Conclusion: The effect of the depth of the thread design was significant for the power-shaped design in enhancing BIC when compared with V-shaped thread design. With high torque V-shaped thread design had more new bone formation as compared with power-shaped thread design.