Affect of Implant Thread Design on Long Term Bone Loss

Objective: To compare bone loss around three thread designs of dental implants with the same micro-structure surface.  

Method: This is a non-randomize retrospective, double blind study. Data were collected by independent group from Tel –Aviv University from patient's records in private office of general practitioner. The protocol was authorized by University Ethic Committee. Only patient's records with confirmed consistent radiological follow-up were selected. Out of 10641implants, 1361 implants inserted in 343 patients met the inclusion criteria. Three thread design of the same implant surface were identified. Group A:  388 implants with dual coronal square threads and apical V threads.  Group B: 911 implants with the same thread structure but with different pitch, depth and thread helix angle. Group C: 62 implants single V thread design. Bone loss was calculated from radiographs with digital caliper measured from implant/abutment connection to bone level.  

Result:

The mean follow-up time was 107 months. Overall implant survival rate was 96.3%. In Group A, 13 implants failed (3.4%), in Group B 37 implants failed (4.1%) and in Group C there were no failures. The average mesial and distal bone loss was 2.03 mm. Average bone loss for Group A, B and C was 2.02 (±1.70) mm, 2.10 (±1.73) mm 1.90 (±1.40) mm respectively. Pairwise comparisons revealed that in Group A SPI implants had less bone loss compared to Group B DFI implants (P=0.036).

Conclusion:

Within the limitations of this study, V-thread dental implants showed the most long term favorable results and the lowest bone loss of the three groups.