Randomized clinical study to compare implant stability and bone loss between different implant designs

Competing macro geometric designs of implants allegedly determine the primary stability and long-term marginal bone maintenance though the sound of randomized evidence is hazy. This split-mouth randomized controlled trial was a comparative study of the tapered and straight design of implants in terms of stability and crestal bone loss in 12 months. Sixty bilateral missing first mandibular molars patients were given one type of implant on a side (tapered, progressive-thread; straight, standard-thread), randomly distributed. Resonance frequency analysis at placement, 3, 6 and 12 months was used to measure implant stability quotient, marginal bone loss was measured at 12 months through cone-beam computed tomography. Tapered implants were found to have much higher mean ISQ at placement (72.4±4.8 vs 68.9±5.2, p=0.001) and at three months (75.1±4.2 vs 72.3±4.9, p=0.007) and thereafter. The loss of crestal bone in tapered implants was 0.82+0.31mm compared to the straight implants that had 1.34+0.45mm (p<0.001). The tapered design of the implants helps to provide initial stability and reduce crestal bone resorption and this is in support of its application in the posterior mandibular position.