Effect of Primary Stability on Short Implants Versus Conventional Implants with a Reverse Concave Neck

PURPOSE: To evaluate the primary stability of short implants vs conventional implants in vitro. MATERIALS AND METHODS: Two groups of implants, short implants (6.0 × 7 mm) and conventional implants (3.75 × 10 mm), with a reverse concave neck and neck microthreads (ULT, Ditron Dental) were studied. A total of 80 implants (40 short implants and 40 conventional implants) were placed by the same calibrated clinician (G.R.) at 800 rpm. Each implant was placed in hard (type 2) and soft (type 4) bone. Implant primary stability was recorded using insertion torque (IT), resonance frequency analysis (RFA), and Periotest values (PTVs). Statistical comparison with one-way analysis of variance (ANOVA) were completed to compare differences between groups. RESULTS: The comparison of IT and RFA values and PTVs of the two implant groups showed statistical significance (P < .0001) favoring the short implants in both the soft and hard bone qualities. CONCLUSIONS: Within the limitations of this study, short implants with a wide diameter seem to have a higher level of implant stability compared to narrow implants with a conventional length.