Rabbit Temporomandibular Joint Research Articles

Bony changes of the condyle following discectomy in the rabbit temporomandibular joint

Session I: TMJ era1 coronoidectomy if intraoperative opening after 1 & 2 is 35mm can be achieved.

Surgical repair of defects in the rabbit temporomandibular joint disc: A comparison of various techniques

A study was designed to evaluate the effects of different types of repair (suture vs. graft), donor graft tissues (dermis vs. fascia), and methods of graft fixation (sutured vs. laser-assisted) on excisional defects of the rabbit TMJ disc made anterior to the retrodiscal tissue. Groups created to compare the different variables were assessed at 30 and 90 days postoperatively by macroscopic and histologic methods, microangiography, and mechanical strength testing. Without repair, all excisional defects of the disc failed to heal. Suturing of the reapproximated margins did not appear to promote healing or provide much strength beyond the properties of the suture material. Dermal grafts, fixed by suturing, induced healing by becoming incorporated into the disc, restoring discal continuity, and approximating normal disc strength. The use of laser-assisted tissue welding for dermal graft fixation was found to be inadequate and was subsequently abandoned. Fascial grafts could be fixed into position by both suture and laser-assistance, but consistently failed to exhibit successful transplantation and promote healing at the disc site.

Distribution of putative elastic fibers in rabbit temporomandibular joint tissues.

This study describes the general distribution of putative elastic fibers in the connective tissues that comprise the articular disk and some of the adnexal tissues of the rabbit temporomandibular joint. Joints were removed en bloc and processed for light-microscopic study. The fibroelastic tissues of the bilaminar zone of the articular disk and the various attachments of the disk to the mandibular condyle contained numerous elastic fibers. Since these morphologic data indicate the presence of many elastic fibers, we suggest that the rabbit temporomandibular joint may serve as a model system to study the functional consequences of selectively altering the quality or quantity of elastic fibers in these tissues.

The effect of diet texture on healing following temporomandibular joint discectomy in rabbits.

This study evaluates the healing of the rabbit temporomandibular joint (TMJ) following discectomy in animals fed coarse or ground diets. Twenty New Zealand rabbits were divided into four groups with two unoperated groups serving as controls. A unilateral discectomy was performed and the animals were placed on either a regular (coarse) or a ground diet immediately following surgery. After 3 months, histologic evaluation demonstrated that fibrocartilage thickness was greatest in the discectomy-coarse diet operated joint, less in the discectomy-ground diet operated joint, still less in the discectomy-coarse diet unoperated joint, and unaffected in the control animals. The results of this study demonstrate that diet texture can affect TMJ healing following discectomy. The adverse responses of the coarse diet affected not only the operated joint but also the unoperated contralateral joint.

Healing of surgical incisions in the disc and retrodiscal tissue of the rabbit temporomandibular joint

The purpose of this study was to evaluate histologically the healing potential of surgical incisions placed in various areas of the TMJ disc and retrodiscal tissue. Eight weeks after surgery, it was found that incisions completely within retrodiscal tissue had healed and had a normal appearance. Incisions at the junction of the disc and retrodiscal tissue also had healed, but at a slower rate and with more random orientation of the collagen fibers. Defects within the disc had not healed, however, and degenerative changes had developed in the hard and soft tissues. The implications of these observations are discussed.

Revascularization of the rabbit temporomandibular joint after surgical intervention: A histologic and microangiographic study

Postsurgical revascularization of the rabbit temporomandibular joint (TMJ) after discoplasty was studied at the gross and microscopic levels. Surgical disruption of the lateral and medial articular blood vessels resulted in revascularization of the joint by the transverse facial artery. Deep branches of the transverse facial artery provided vascular supply to the anterior TMJ until the lateral and medial articular vessels could be re-established. The greatest change in vascularity was observed between the second and third postoperative weeks. It was concluded that discoplasty in the rabbit TMJ is a biologically sound surgical procedure, with the majority of vascularity re-established by three weeks and complete healing at six weeks.

Arthroscopy of the rabbit temporomandibular joint

Arthroscopy of the rabbit temporomandibular joint was evaluated experimentally on 22 rabbits. A small arthroscope with socalled “Selfoc”-system was employed. The reaction to arthroscopy was analyzed clinically. Macroscopic dissection and histology were then employed to detect possible pathological changes in the joints at periodic intervals. The established criteria for evaluation of postoperative reactions were erythema, suppuration, weight changes and chewing capacity. The results of this study indicate that the rabbit temporomandibular joint may be arthroscoped with subsequent minor reversible changes. It also seems feasible to assume that temporomandibular joint arthroscopy in humans runs a low risk for postoperative complications.

The effects of immobilization on the rabbit temporomandibular joint

While the effects of immobilization of joints covered with hyaline cartilage have been widely studied, the effects on the fibrous tissue-covered temporomandibular joint have not been studied as extensively. This study was designed to determine the short-term effects of immobilization on the rabbit temporomandibular joint. Nineteen rabbits were placed in maxillomandibular fixation. The temporomandibular joints were studied histologically after periods of from ten to 28 days. Significant thinning was observed as early as after ten days, as was degeneration of the cartilage. Degeneration became progressively more severe as the duration of the immobilization increased. Reparative events began appearing after 28 days. These findings suggest that although initially immobilization produces destructive changes, the changes may well be reversible.