Effect of untreated and treated temporomandibular joint arthritis on mandibular volume development in growing rabbits.
OBJECTIVE
The goal of this work was to investigate the volume development of the mandible in growing rabbits with bilaterally induced temporomandibular joint (TMJ) arthritis that was either left untreated or treated with the tumor necrosis factor-alpha (TNF-α) antagonist etanercept.


METHODS
A total of 18 New Zealand White rabbits aged 8 weeks were randomized to three groups of 6 animals each. Two of these groups were used as arthritis groups by sensitizing the 12 animals to ovalbumin (OA) at 10 weeks, followed by intraarticular OA injections to induce bilateral TMJ arthritis and repeating these injections every 3 weeks to maintain the inflammation. One of the two arthritis groups was treated by weekly subcutaneous etanercept injections, whereas the other group was left untreated. The remaining 6 animals served as controls. Maxillofacial CT scans were obtained at 3-week intervals (from week 10 of the rabbits' lives to the end of the experiment at 22 weeks) to volumetrically track the development of the mandibles after segmentation.


RESULTS
The mandibles did not grow at a continuous rate, but the rate of development was found to decrease in all groups over the course of the study (weeks 10-22). The most extensive volume increases were noted during weeks 10-13. Severe growth deficiencies, especially of the condylar processes, were observed in the arthritis group not receiving treatment. The arthritis group treated with etanercept showed better rates of growth without, however, reaching the normal range of the control group.


CONCLUSIONS
Antigen-induced TMJ arthritis was found to involve severe problems of growth similar to those in juvenile idiopathic arthritis. Etanercept can improve the volume development but does not reestablish an entirely normal rate of growth.
Department of Orthodontics, Dentofacial Orthopedics and Pedodontics, Charité Center for Dental, Oral and Maxillofacial Medicine, Charité - Universitätsmedizin Berlin, Assmannshauser Str. 4-6, 14197, Berlin, Germany, thomas-michael.praeger@charite.de.
Thomas Michael
TM
Präger
Smbat
S
Rafayelyan
Helga
H
Landau
Nicole
N
Pischon
Kirsten
K
Minden
Paul-Georg
PG
Jost-Brinkmann
Ralf
R
Müller-Hartwich
Axel
A
Mußler
D000375:Aging / Q000473:pathology; D000818:Animals; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001168:Arthritis / Q000188:drug therapy* / Q000473:pathology*; D000068800:Etanercept / Q000627:therapeutic use*; D005260:Female; D008334:Mandible / Q000187:drug effects / Q000473:pathology*; D009929:Organ Size / Q000187:drug effects; D011817:Rabbits; D012016:Reference Values; D013705:Temporomandibular Joint Disorders / Q000188:drug therapy* / Q000473:pathology*; D016896:Treatment Outcome
D018501:Antirheumatic Agents; D000068800:Etanercept