Effect of placement angle on the stability of loaded titanium microscrews in beagle jaws

ABSTRACT Objective: To evaluate the effect of insertion angle on stability of loaded titanium microscrews in beagle jaws. Materials and Methods: Forty-eight microscrews were inserted at four different angles (30°, 50°, 70°, and 90°) into the intraradicular zones of the mandibular first molars and third premolars of 12 beagles and immediately loaded with a force of 2 N for 8 weeks. Microcomputed tomography (micro-CT) and biomechanical pull-out tests were used to assess osseointegration of the interface. Results: All micro-CT parameters and maximum pull-out force (FMAX) of the microscrews were affected by insertion angles of microscrews. Higher micro-CT parameters and FMAX were seen for implants inserted at angles between 50° and 70° (P < .05). Excessive oblique and vertical insertion angles resulted in reduced stability (P < .05). Conclusion: An insertion angle of 50° to 70° is more favorable than excessive oblique or vertical angles to achieve stability of microscrews.