Short vs. Standard Length Cone Morse Connection Implants: An In Vitro Pilot Study in Low Density Polyurethane Foam

The aim of the investigation was to evaluate the insertion torque, pull-out torque and implant stability quotient (ISQ) of short implants (SI) and standard length implants (ST) inserted into linearly elastic and constitutive isotropic symmetry polyurethane foam blocks. Short dental titanium implants with a Cone Morse connection and a conical shape (test implants: Test Implant A-diameter 5.5 mm and length 6 mm) (Test Implant B-diameter 5.5 mm and length 5 mm) were used for the present in vitro investigation. ST implants (4 mm diameter and 10 mm length), with a Cone Morse connection and a conical shape, were used as Control Implant A and as Control Implants B. These two latter implants had a different macro design. A total of 20 implants (5 Test A, 5 Test B, 5 Control A and 5 Control B) were used for the present research. The results were similar when comparing the Test A and Test B implants. The test implants had very good stability in polyurethane 14.88-29.76 kgm(3) density blocks. The insertion torque values were very high for both types of test implant (25-32 Ncm on 14.88 kgm blocks, and up to 45 Ncm in 29.76 kgm(3) blocks). The pull-out test values were very similar to the insertion torque values. The ISQ values were significantly high with 75-80 in 14.88 kgm(3) blocks, and 78-83 in 29.76 kgm(3) blocks. No differences were found in the values of the Control A and Control B implants. In both these implants, the insertion torque was quite low in the 14.88 kgm(3) blocks (16-28 Ncm). Better results were found in the 29.76 kgm(3) blocks. The pull-out values for these control implants were slightly lower than the insertion torque values. High ISQ values were found in both control implants (57-80). When comparing SI and ST implants, the SI had a similar if not better performance in low quality polyurethane foam blocks (14.88-29.76 kgm), corresponding to D3 and D4 bone.