Bone strains around immediately loaded implants supporting mandibular overdentures in human cadavers.
OBJECTIVE
To compare the biomechanical effect of splinted versus unsplinted mandibular implants supporting overdentures subjected to experimental static immediate load on bone tissue deformation using strain gauge analysis.


METHODS
Strain gauges were bonded on the labial cortical bone adjacent to 2 Straumann dental implants placed in the mandibular interforaminal region of 4 completely edentulous mandibles of fresh human cadavers. The installation torque value (ITV) of each implant was measured using a custom-made torque wrench, and implant stability quotients (ISQs) were also obtained using resonance frequency analysis. Three overdentures (ODs), 2 splinted (bar- and cantilevered bar-retained) and 1 unsplinted (ball-retained), were fabricated for each edentulous mandible. Two experimental loads were applied subsequently via 2 miniature load cells that were placed bilaterally 10 mm (anterior loading) and 15 mm (posterior loading) from the implant. Strain measurements were performed at a sample rate of 10 KHz and under a maximum experimental static load of 100 N; they were simultaneously monitored from a computer connected to a data acquisition system. Finally, the removal torque values (RTV) of the implants were measured.


RESULTS
Strains on the labial cortical bone around implants supporting mandibular ODs under anterior loading were significantly higher than measured under posterior loading for all attachment types (P < .05). All strain values were compressive in nature, and the minimum strain (-19 microepsilon) was recorded for bar-retained ODs under 25 N posterior loading, while the maximum strain (-797 microepsilon) was for recorded for retentive anchor-retained ODs under 100 N anterior loading. Nonparametric correlations between ISQs, ITVs, and RTVs identified significant correlations only for ITVs and RTVs (P < .05).


CONCLUSIONS
Splinting of 2 interforaminal dental implants, regardless of attachment type, to support mandibular ODs subjected to immediate load significantly reduced initial bone tissue strains experienced on the labial cortical bone in comparison with the use of unsplinted implants.
Akça
Kivanç
K
Department of Prosthodontics, Faculty of Dentistry, Hacettepe University, Sihhiye, Ankara, Turkey. akcak@hacettepe.edu.tr
Akkocaoglu
Murat
M
Cömert
Ayhan
A
Tekdemir
Ibrahim
I
Cehreli
Murat Cavit
MC
D000539:Alveolar Process / Q000503:physiopathology; D002102:Cadaver; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D003779:Denture Design; D003781:Denture Retention; D003828:Denture, Overlay; D006801:Humans; D007575:Jaw, Edentulous / Q000503:physiopathology / Q000601:surgery; D008334:Mandible / Q000503:physiopathology* / Q000601:surgery; D012815:Signal Processing, Computer-Assisted; D013314:Stress, Mechanical; D019415:Torque; D014159:Transducers
D015921:Dental Implants