Tetracalcium Phosphate Graft for Implant Stabilization: Resonance Frequency and Histomorphometric Analysis in a Sheep Tibia Model

Background: This study aimed to evaluate the effects of tetracalcium phosphate (TTCP) graft material on the stability and osseointegration of dental implants placed in anatomically compromised bone. Materials and Methods: Six healthy sheep were used following ethical approval. Osteotomies were created in the tibial region and divided into three groups: Group A (control, n = 12) with standard osteotomy; Group B (n = 12) with enlarged and deepened osteotomy; and Group C (n = 36), where osteotomy sites were filled with TTCP prior to implant placement. Implant stability was measured using the resonance frequency analysis (RFA), and osseointegration was evaluated histologically by bone-to-implant contact percentage (BIC%). Animals were sacrificed at the 3rd and 6th weeks for histological analysis. Results: Initial RFA values exceeded 42.5 in all groups. Group C demonstrated the highest RFA at Week 6 (79) and significantly higher RFA values at Week 3 compared to other groups, while Group B consistently showed the lowest stability. At Week 3, Group A exhibited the highest BIC% (28.04 ± 5.05%). By Week 6, BIC% increased in all groups, with no significant intergroup differences. Robust ANOVA revealed significant effects of time and group on both RFA and BIC%. Conclusions: TTCP significantly enhanced implant stability and osseointegration in compromised bone, providing improved secondary stability and suggesting its potential clinical benefit in challenging anatomical conditions.