Human ex vivo bone tissue strains around natural teeth vs. immediate oral implants.
OBJECTIVE
To compare ex vivo bone tissue strains around natural teeth with immediate implants supporting unsplinted and splinted fixed prostheses.


METHODS
Six linear strain gauges were bonded on the labial marginal bone of bilateral maxillary anterior teeth in two fresh-frozen human cadavers. The natural teeth were loaded in centric occlusion via an occlusal splint with integrated miniature load cells. 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. Upon extraction of the anterior teeth, Ø 4.1 mm and Ø 4.8 mm ITI dental implants were placed into sockets of incisors and canines, respectively. Installation torque value (ITV) of each implant was measured by a custom-made torque wrench and resonance frequency analyses (RFA) were also undertaken. Strain measurements were performed for (1) single-tooth implant restorations, (2) unilateral splinted anterior implants, and (3) bilateral splinted anterior implants. Finally, an autopolymerizing acrylic resin was injected into the implant sockets for simulation of osseointegration and strain measurements were performed.


RESULTS
Microstrains of all groups were statistically comparable (P>0.05), although lower strains were elicited for implants in sockets of incisors in comparison with natural teeth. Microstrains around canine implants were comparable or higher than those induced around natural canines. For all groups, microstrains around canines were higher than those around lateral (P<0.05) and central incisors (P<0.01), which had similar strain levels (P>0.05). The RFA values of implants were comparable. The ITVs of implants in sockets of lateral incisors and canines were similar and were higher than those of implants in central incisor regions.


CONCLUSIONS
The labial marginal bone having no contact with immediate implants may experience strain gradients within physiologic levels due to deformation of bone under load. Although one prosthetic design does not seem to have clear advantages over another, splinting of implants may be considered as a safety measure for immediately loaded immediate implants, if possible.
Cehreli
Murat Cavit
MC
Department of Prosthodontics, Faculty of Dentistry, Hacettepe University, Sihhiye, Ankara, Turkey. mcehreli@hacettepe.edu.tr
Akkocaoglu
Murat
M
Comert
Ayhan
A
Tekdemir
Ibrahim
I
Akca
Kivanc
K
D000328:Adult; D001842:Bone and Bones / Q000737:chemistry / Q000502:physiology*; D002102:Cadaver; D015921:Dental Implants; D006801:Humans; D008297:Male; D008875:Middle Aged; D017090:Occlusal Splints; D018709:Statistics, Nonparametric; D013997:Time Factors; D016474:Weight-Bearing
D015921:Dental Implants