Microstructural and ultrastructural assessment of inferior alveolar nerve damage following nerve lateralization and implant placement: an experimental study in rabbits.
OBJECTIVE
The present study assessed damage to the inferior alveolar nerve (IAN) following nerve lateralization and implant placement surgery through optical and transmission electron microscopy (TEM).


METHODS
IAN lateralization was performed in 16 adult female rabbits (Oryctolagus cuniculus). During the nerve lateralization procedure, one implant was placed through the mandibular canal, and the IAN was replaced in direct contact with the implant. The implant was placed in the right mandible, and the left side was used as a control (no surgical procedure). After 8 weeks, the animals were sacrificed and samples were prepared for optical and TEM analysis of IAN structural damage. Histomorphometric analysis was performed to determine the number and cross-sectional dimensions of nerve fascicles and myelin sheath thickness between experimental and control groups. The different parameters were compared by one-way analysis of variance at the 95% significance level.


RESULTS
Alterations in the perineural and endoneural regions of the IAN, with higher degrees of vascularization, were observed in the experimental group. TEM showed that the majority of the myelinated nerve fibers were not affected in the experimental samples. No significant variation in the number of fascicles was observed, significantly larger fascicle height and width were observed in the control group, and significantly thicker myelin sheaths were observed in the experimental samples.


CONCLUSIONS
IAN lateralization resulted in substantial degrees of tissue disorganization at the microstructural level because of the presence of edema. However, at the ultrastructural level, small amounts of fiber degeneration were observed.
Instituto de Pesquisas Energéticas e Nucleares/Centro de Ciências e Tecnologia de Materiais in São Paulo, Brazil.
Marcelo
M
Yoshimoto
Il-sei
IS
Watanabe
Marília T
MT
Martins
Marcos B
MB
Salles
Gary R
GR
Ten Eyck
Paulo G
PG
Coelho
D019412:Anatomy, Cross-Sectional; D000818:Animals; D001369:Axons / Q000648:ultrastructure; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D005260:Female; D008334:Mandible / Q000294:innervation / Q000601:surgery*; D008340:Mandibular Nerve / Q000601:surgery / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission; D009186:Myelin Sheath / Q000648:ultrastructure; D009410:Nerve Degeneration / Q000209:etiology / Q000473:pathology; D009413:Nerve Fibers, Myelinated / Q000648:ultrastructure; D036421:Nerve Fibers, Unmyelinated / Q000648:ultrastructure*; D019635:Neurosurgical Procedures / Q000379:methods*; D010027:Osteotomy / Q000295:instrumentation / Q000379:methods; D011817:Rabbits; D013997:Time Factors; D061221:Trigeminal Nerve Injuries
D015921:Dental Implants