Title: Translational Model for Temporomandibular Disorder (TMD)- a Functional Phenotypic Study
Medha Rao, Ernst Mario School of Pharmacy
David Reimer, Comparative Medicine Resources, Rutgers University
Derek Adler, Rutgers University
Samuel Quek, Rutgers School of Dental Medicine
Gayathri Subramanian, Rutgers School of Dental Medicine
Ed Yurkow (Presenter)
Objectives: The pathogenesis of TMDs is complex, possibly involving a combination of pathological events including, but not limited to, the misalignment of jaw structures, increased pain perception and alterations in the physiology of the muscles controlling jaw movement. Advancement in our understanding of TMD is hindered by the lack of animal models for this condition. Our collaborative research group has developed a rat model of TMD when optimized, can potentially be used to test hypotheses associated with the etiology of this condition, devise and evaluate therapies.
Methods: 4 male and 8 female Sprague Dawley and 8 female Long Evans rats were subjected to maxillary molar extractions on the left (standard extraction protocol, Method A) or right side (standard extractions preceded by sonication utilizing an ultrasonic scaler, Method B). Post-extraction healing was monitored clinically. Sodium Fluoride- Positron Emission Tomography (NaF18-PET) imaging was obtained at baseline, 2 and 4 weeks post-extraction. The animals were weighed and evaluated periodically.
Results: The extraction sites healed uneventfully in both groups. Rats subjected to Method B developed orofacial pain that hindered feeding, and failure to gain weight that was rescued by switching the rats to a soft gel diet. Pain grimace was observed on occasion in rats subjected to dental extractions using Method B. The pattern of NaF18- PET uptake at the extraction sites is being evaluated currently. However, our results are consistent with the development of chronic musculoskeletal pain in the masticatory apparatus.
Conclusions: Our preliminary results suggest that we have developed a translational model of TMD that appears to be reproducible, measurable and predictable. Characterizing this model more extensively, for example, using bite force measurement, pain behavior assessment and fluoro-deoxyglucose (FDG)-PET imaging will enable us to objectively describe disease burden and evaluate potential therapeutic interventions.