[Experimental study of the primary stability of dental implants using different osteotomy protocols].

OBJECTIVE

To evaluate the influence of an undersized drilling protocol on primary stability of «A2» dental implants in low-density D3-D4 bone using a comprehensive diagnostic approach.

MATERIALS AND

METHODS

An in vitro study was performed on two porcine vertebral bone macro-specimens and «Sawbones» polyurethane blocks of four densities. Density was assessed by shadow and echo-pulsed ultrasonographic densitometry. Two experimental models were created; in each, six implants of the A2 system were placed with dimensions of 3.5×6.6 mm (A6.6) and 3.5×11 mm (A11). In all cases, an undersized drilling protocol with subcrestal placement (1-2 mm) was applied. The osteotomy bed was prepared with a 2 mm pilot drill and a three-fluted bur, followed by a conical reamer. Implant placement was performed using the «W&H Implantmed Plus» physiodispenser with torque curve registration. Primary stability was assessed by resonance frequency analysis (ISQ) using the «Osstell Beacon»; implant position was verified by CBCT (Axeos, Dentsply Sirona). Statistics included mean, standard deviation (SD), 95% confidence intervals (CI) and coefficient of variation (CV).

RESULTS

In polyurethane blocks: shadow densitometry 952-1344 m/s; echo-pulsed ultrasonographic densitometry 1870-2674 m/s. In porcine bone, trabecular bone was 1408-1500 m/s and cortical up to 2303 m/s; the model corresponded to D3-D4 density. In group «A11», torque at placement was 31.67±4.80 N·cm, ISQ=81.92±1.12, torque at removal 37.00±4.43 N·cm; in «A6.6» -23.33±3.61; 71.83±7.22 and 22.33±6.19, respectively. Differences were statistically significant.

CONCLUSION

The undersized drilling protocol provides high primary stability in low-density D3-D4 bone. Ultrasonic densitometry may serve as an additional objective method for assessing bone quality and selecting an appropriate drilling protocol to predict primary stability. A comprehensive diagnostic approach supports optimization of the surgical protocol and reduces the risk of early postoperative complications.