Human ex vivo bone tissue strains around immediately-loaded implants supporting mandibular fixed prostheses.
OBJECTIVE
The purpose of this study was to qualify and quantify bone strains around immediately-loaded implants supporting mandibular fixed prostheses with regard to number of implant support.


METHODS
Linear strain gauges were bonded on the labial bone of 5 Straumann dental implants placed in the mandibular symphysis region of 2 completely edentulous mandibles of fresh human cadavers. Installation torque value of each implant was measured by a custom-made torque wrench and resonance frequency analyses were undertaken. A one-piece full-arch fixed prosthesis was fabricated for each cadaver and 2 miniature load cells were integrated in the cantilever region of the prostheses for controlled loading experiments. 5-, 4-, and 3-implant support designs were consecutively tested. Strain measurements were performed at a sample rate of 10 KHz and under a maximum load of 100 N, simultaneously monitored from a computer connected to data acquisition system.


RESULTS
The installation torque values and implant stability quotient values of the implants ranged between 42.12 to 145.67 N cm and 61 to 80, respectively. Between-group comparisons revealed that the highest strain magnitudes were recorded for the 3-implant design followed by the 4- and 5-implant designs, although there was a tendency toward similar load partitioning between 4- and 5-implant designs (P < 0.05).


CONCLUSIONS
Bone strains around 3-implant supported mandibular fixed prostheses is significantly higher than those around 4- and 5-implant designs, and this may lead to failure of supporting implants. Four- and 5-implant designs might have similar clinical outcome.
Department of Prosthodontics, Yeditepe University, Goztepe, Istanbul.
Ali Murat
AM
Kökat
Ayhan
A
Cömert
Ibrahim
I
Tekdemir
Murat
M
Akkocaoğlu
Kvanç
K
Akça
Murat Cavit
MC
Cehreli
D000368:Aged; D000539:Alveolar Process / Q000502:physiology*; D002102:Cadaver; D003758:Dental Implantation, Endosseous; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000295:instrumentation / Q000379:methods; D003825:Denture, Complete, Immediate; D003826:Denture, Complete, Lower; D006801:Humans; D007575:Jaw, Edentulous / Q000503:physiopathology / Q000534:rehabilitation; D008297:Male; D008875:Middle Aged; D013997:Time Factors; D019415:Torque