Efficacy of biologically guided implant site preparation to obtain adequate primary implant stability

The primary stability of dental implants is essentially influenced by the quality and quantity of hosting bone. To study the effects of adaptation of the drilling protocol to the biological quality of bone estimated by bone density and cortical/cancellous bone ratio, 8.5 mm-short implants were placed in different bone types by adapting the drilling protocol to result in a socket under-preparation by 0.2, 0.4, 0.7, 1 and 1.2 mm in bone types I, II, III, IV and V, respectively. The effect of the drilling protocol was studied on implant insertion torque and osseointegration. Additionally, we analyzed the relationship of demographic data and social habits to bone type and insertion torque. Then the correlation between insertion torque and bone quality was tested. One hundred ninety two patients (mean age: 62 ± 11 years) participated with 295 implants. The most common bone type at implant site was type III (47.1%) followed by type II (28.1%). Data analysis indicated that gender, age, and social habits had neither correlation with bone type nor with insertion torque. The insertion torque was 59.29 ± 7.27 Ncm for bone type I, 56.51 ± 1.62 Ncm for bone type II, 46.40 ± 1.60 Ncm for bone type III, 34.84 ± 2.38 Ncm for bone type IV and 5 Ncm for bone type V. Statistically significant correlation was found between bone type and insertion torque. The followed drilling protocol adapts socket under-preparation to the needs of establishing a sufficient primary stability for implant osseointegration.