Replacement of the condyle and ascending ramus by a modular endoprosthesis in Macaca fascicularis--part 4: evaluation of the temporomandibular joints.
OBJECTIVE
To assess, using cone-beam computed tomography and histologic examination, whether the fixation of a condyle-ascending ramus mandibular modular endoprosthesis results in a physiologic condylar replacement in Macaca fascicularis.


METHODS
The right condyle and ascending ramus were resected in 8 adult monkeys and replaced with a modular endoprosthesis, fixed with polymethyl methacrylate bone cement (Palacos). Four monkeys were sacrificed at 3 months and another 4 at 6 months postoperatively. The reconstructed and contralateral temporomandibular joints were harvested en bloc and studied using cone-beam computed tomography and descriptive histologic examination. Heterotopic bone formation was quantified using a modified grading scale. The condyle cartilage thickness in the contralateral temporomandibular joint was measured using histomorphometric methods. The results were compared with those of the unoperated control monkeys.


RESULTS
Bone resorption in the glenoid fossa and pathologic changes in the articular disc were noted on the reconstructed side in most specimens. Nevertheless, cone-beam computed tomography findings, histologic findings, and condyle cartilage thickness measurements of the contralateral temporomandibular joint were not significantly different from those of the control specimens.


CONCLUSIONS
Replacement of the condyle and ascending ramus using a modular endoprosthesis in Macaca fascicularis resulted in adaptive remodeling of the glenoid fossa at up to 6 months postoperatively. Long-term studies are required to further assess the potential of this mode of reconstruction.
Goh
Bee Tin
BT
National Dental Centre, Singapore, Singapore. gohbee@starhub.net.sg
Lee
Shermin
S
Tideman
Henk
H
Jansen
John A
JA
Stoelinga
Paul J W
PJ
D000818:Animals; D001843:Bone Cements; D016723:Bone Remodeling; D001862:Bone Resorption / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology; D002484:Cementation; D054893:Cone-Beam Computed Tomography; D007595:Joint Prosthesis; D008252:Macaca fascicularis; D008297:Male; D008334:Mandible / Q000601:surgery*; D008335:Mandibular Condyle / Q000601:surgery; D008341:Mandibular Prosthesis; D019930:Mandibular Prosthesis Implantation / Q000379:methods*; D023421:Models, Animal; D009999:Ossification, Heterotopic / Q000473:pathology; D019904:Polymethyl Methacrylate; D013701:Temporal Bone / Q000473:pathology; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging / Q000502:physiology*; D019224:Temporomandibular Joint Disc / Q000473:pathology
D001843:Bone Cements; D019904:Polymethyl Methacrylate