Missing posterior teeth and risk of temporomandibular disorders.
There is disagreement about the association between missing posterior teeth and the presence of temporomandibular disorders (TMD). Here, the purpose was to investigate whether the number of missing posterior teeth, their distribution, age, and gender are associated with TMD. Seven hundred and forty-one individuals, aged 21-60 years, with missing posterior teeth, 386 with and 355 without TMD, were included. Four variables-gender, age, the number of missing posterior teeth, and the number of dental quadrants with missing posterior teeth-were analyzed with a logistic regression model. All four variables—gender (OR = 1.59, men = 1, women = 2), age (OR = 0.98), the number of missing posterior teeth (OR = 0.51), and the number of dental quadrants with missing posterior teeth (OR = 7.71)—were entered into the logistic model (P < .01). The results indicate that individuals who lose posterior teeth, with fewer missing posterior teeth but in more quadrants, have a higher prevalence of TMD, especially young women.
Temporomandibular disorder (TMD) refers to a number of clinical problems that involve masticatory musculature, temporomandibular joints, and related structures or both. The etiology and treatment remains contentious. Interaction of morphologic and functional occlusal factors relative to TMD indicates a fairly low association of occlusal factors in characterizing TMD. Skeletal anterior open bite, overjets greater than 6 mm to 7 mm, retruded cuspal position/intercuspal position slides greater than 4 mm, unilateral lingual crossbite, and five or more missing posterior teeth are the five occlusal features that have been associated with specific diagnostic groups of TMD conditions.1 The association of occlusion and orthodontic treatment and TMD is minor. Signs and symptoms of TMD occur in healthy individuals and increase with age, particularly during adolescence; thus, temporomandibular disorders that originate during various types of dental treatment may not be related to the treatment but may be a naturally occurring phenomenon.1
The association between missing mandibular posterior teeth and the development of TMD remains unclear but some recent clinical studies have investigated the link between the two from an intra-articular and muscular standpoint. Does loss of posterior teeth contribute to an acceleration in the development of degenerative joint disease? Should clinicians make recommendations for posterior tooth replacement for occlusal support and prevention of TMD? Typically recommendations to patients to save a posterior tooth relates to potential tooth movement and super-eruption of the opposing teeth. These changes can contribute to TMD, but whether or not that link is explained to the patient is not consistent among clinicians.
This research study and others point to the need to educate our patients when teeth have significant pathology that would cause a patient to opt for extraction, and that there is an importance to maintaining an intact posterior occlusion to avoid possible TMD.
1. McNamara JA Jr, Seliqman DA, Okeson JP. Occlusion, orthodontic treatment and temporomandibular disorders: a review.J Orofac Pain. 1995;9(1):73-90.
Commentary by Howard E. Strassler, DMD
Howard E. Strassler, DMD
Professor, Division of Operative Dentistry
Department of Endodontics, Prosthodontics and Operative Dentistry
University of Maryland Dental School