Purpose : The purpose of this study is the influence of immediate loading on primary stability in three different type thread implants
which were designed to enhance primary stability.
Materials and Methods : The implants used in this experiment had RBM surface and tapered design (COTEC implant). In 10
Mongrel dogs, the 1st, 2nd, 3rd and 4th mandibular premolars were extracted bilaterally and implants were inserted after 1 month .
Total 40 fixtures were placed and 2 implants were immediately loaded and other 2 implants were not loaded in each dog. Animals
were sacrificed at 1, 2, 4, 8, and 16 weeks. When implants were inserted and the animals were sacrificed, RFA( Resonance Frequency
Analysis) and PTV(Periotest value) were measured. Gross, radiological, histologic and histomorphometric examinations were done
and BA(bone area) and BIC(bone to implant contact) were measured by KAPPA IMAGE BASE. The t-test and 2-way ANOVA were
undertaken for statistical analysis (p<0.05).
Result & Conclusion : 1. In case of immediate loading group, crestal bone loss was observed in many cases as time goes by. But in
the unloaded group , crestal bone was well maintained.
2. In RFA and PTV, both group represent high stability.
3. In the coronal area, control group showed higher value than experimental group on the BIC. As for the BA, control group showed
higher value than experimental group except 4 week.
4. In the middle area, as for the BIC, experimental group showed higher value than control group except 8 week. As for the BA,
experimental group showed higher value than control group at 2, 4, 8 week.
Although the implant that have 3 different shape threads are designed to better primary stability, immediate loading can cause bad
result as marginal bone resorption. Further studies may be necessary with different conditions such as loading method, different
thread design, better hygiene, controlled temporary crown occlusion, increased number of specimens, and improved measuring
methods. [THE JOURNAL OF THE KOREAN ACADEMY OF IMPLANT DENTISTRY 2011;30(1):16-26]