Undersized Implant Site Preparation to Enhance Primary Implant Stability in Poor Bone Density: A Prospective Clinical Study

Journal of Oral and Maxillofacial Surgery
Volume 69, Issue 12 , Pages e506-e512, December 2011


Achieving primary implant stability in areas with poor bone density is often challenging to the clinician. Previous research has suggested that modified surgical protocols might be beneficial in such situations. The objective of the present clinical study was to evaluate the survival rate of implants placed using undersized implant site preparation in areas with poor bone density.

Materials and Methods

A total of 52 implants were placed in 29 patients. Of the 52 implants, 26 were surgically placed according to the standard drilling protocol (control group) and 26 were placed in low-density bone using an adapted bone drilling method (test group). The maximum insertion torque values and resonance frequency analysis measurements were also recorded. All implants were examined clinically and radiographically at follow-up visits during the study period. Oral hygiene status, bleeding on probing, peri-implant probing depth, and implant survival rate were assessed.


According to the survival criteria used in the present study, no failure was recorded, and the overall survival rate was 100% for both groups after 12 months. The mean probing depth was 2.75 ± 0.75 mm in the test group and 2.87 ± 0.79 mm in the control group. The mean insertion torque value was 35.19 ± 4.79 Ncm in the test group and 34.62 ± 5.82 Ncm in the control group. The resonance frequency analysis value was 68.58 ± 4.81 implant stability quotient and 66.69 ± 5.41 implant stability quotient in the test and control groups, respectively. The observed differences were not statistically significant (P > .05).


The results of the present study suggest that placement of implants by an adapted drilling technique in sites with poor bone density is beneficial in enhancing primary implant stability and improving the implant survival rate.


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