Mandibular Joint, Orthodontic and Dental Findings in EDS

by: J. Vitagliana, L.A. Norton, L.A. Assael
University of Connecticut School of Dental Medicine Farmington, CT 06030

Ehlers-Danlos syndrome (EDS) is an unusual syndrome affecting many organ systems and tissue functions through the expression of defective collagen. Although simply stated as a defect in collagen, these disorders are extremely heterogeneous expressing many subtypes. At the molecular level, a variety of defects occur, varying from mutations involving the genes that produce collagen, to those involving the enzymes that are responsible for post-transcriptional modifications of m-RNA. These various molecular lesions result in the expression of EDS as a clinically heterogeneous disorder with several patterns of inheritance. Thus the clinical expression of these syndromes is variable and difficult to recognize.

The most common subtypes of EDS are types I, II, and III. These three are inherited as an autosomal dominant disease. The hallmark of EDS type I is the hyperelasticity and soft velvety texture of the skin that is fragile and bruises easily. Generalized joint instability is another marked feature of EDS type I. This encompasses recurrent dislocations of all major joints with potential to develop fragile vessel walls. Hematomas frequently encountered are a result of weakened vascular walls. A patient may complain of muscular cramps due to muscular hypotonia and weakness secondary to orthopedic stresses. Type II is reminiscent of type I, yet clinical symptomatology is less severe. Skin hyperelasticity, skin laceration, scarring and bruising are mild to moderate in severity. Type III, according to Fialkow, is the most common form of EDS. The remarkable feature is gross hypermobility in all joints. Patients afflicted with type III may demonstrate hyperelastic tissue sketching without undue stress. Other dermatological considerations of EDS are mild. Type IV, also known as ecchymotic type, has little evidence of skin hyperelasticity and joint hypermobility. A type III collagen defect is responsible for the marked skin fragility and easy bruisability. Mitral valve prolapse is prevalent as it is in types I and II. Type V, the only X-linked type of EDS, is characterized by musculoskeletal disorders, with little skin and joint symptoms. Type VI, ocular type, is characterized by fragility of the eye, cornea, and sclera, with pronounced skin and joint fragility. Type VII is characterized by patients with very short stature, with decided joint hypermobility and dislocations. Type VIII patient’s major complication is fragile skin and advanced periodontal disease. These patients often lose their teeth at a very early age.

Many dental manifestations of EDS have been documented. These should be taken into account when treating the dental patients with EDS. The most common of these findings include hypermobile temporomandibular joints (TMJ), a high incidence of TMJ dislocation, fragile oral mucosa, severe susceptibility to periodontitis, predilection for enamel fractures, pulp stones, tooth mobility and difficulties with orthodontic retention. All aspects of dental treatment should be modified according to the EDS pathologic expression and risk.

EDS patients need routine dental care. The purpose of this study was to identify the problems in treating the EDS population’s dental needs. In our attempt to address these considerations, we performed a small study that compared a group of EDS patient’s orthodontic experience with those of a control sample of non EDS orthodontic patients. In addition, an assessment of temporomandibular disorders (TMD) was made on both groups.

Material and Methods:
The data were collected through a mailed survey which was sent to members of the Ehlers-Danlos National Foundation (EDNF). The EDNF provides support and updated information to those who suffer from the disorder and serves as a vital information link to and from the medical and dental community. Loose Connections, (volume 8) the EDNF publication, was used to distribute our survey. Although all members of EDNF were sent the questionnaire, the responses to our survey were few, totaling 57. In order to make comparisons, we did a similar study on 35 patients taken from a random sample of patients from private orthodontic practices. The questionnaire was made of two sections, one section filled out by the patient, the other by the practitioner. The survey included yes and no questions, and scales of frequency for certain dental symptoms. The control group questionnaire was an abridged version of the EDS patient’s questionnaires.

Results:
Of the sample reported, there were 22.8% type I, 7% type II, 35.1% type III, 3.5% type IV, 1.8% type VI, 5.3% type VIII, 11.8% type IX, and 22.8% of unknown type. Types I, II, and VIII had the highest percentage of patients who experienced difficult orthodontic treatment. 30.8%, 35%, and 100% respectively. 35.1% of the EDS population found their treatment to be easy, 33.3% tolerable, and 31.6% difficult. In the control sample none of the patients found their dental experience to be difficult, and the percentages were almost equally split between tolerable and easy. Length of orthodontic treatment time for all EDS groups were consistent with the control group. Unfortunately, more complex problems take more time to treat and a comparison based on this information may be of limited value. However, the probability of rapid relapse necessitates the need for life long retention. The frequency of dislocation and subluxation of the temporomandibular joint for the EDS population was much higher than the control groups. 47.4% of the EDS population experienced some sort of TMJ symptoms while none of the control group experienced these similar dislocations. EDS types I and II experienced high rates of jaw dislocation at 84.6% and 100% respectively. Type III experienced a slightly lower incidence of jaw dislocation, 35%.

Discussion:
Previous studies have shown that the oral findings in EDS play a significant role in treating these patients. The high frequency of TMJ subluxation is a major concern when dealing with these patients. Obviously, caution must be taken in performing any type of dental procedure, especially those requiring the patients to have their mouths open for long periods of time. The TMJ often demonstrates profound laxity in conjunction with generalized joint mobility and dislocation in these patients. Genetically defective collagen biosynthesis directly affects the fibrous stability of the retrodiscal tissues, thus causing recurrent subluxation. Recurrent subluxation was described by Goodman and Allison. The modality that is described is that of reducible, anteriorly displaced disk with an overlying neuromuscular component. Thexton et al reported similar clinical findings of "recurrent" yet "easily reducible dislocations" which disappeared as "the joints grew older with age". Joint disturbances are often secondary to laxity in joint tendons and ligaments. Current therapy for these symptoms includes occlusal splints, anti-inflammatory agents, muscle relaxants, and physical therapy. Temporomandibular joint surgery is sometimes indicated to control subluxation.

The periodontal status in the patients also needs to be closely monitored both clinically and radiographically in these patients. These tissues are very prone to gingivitis, periodontitis, and severe bleeding after invasive procedures. The oral mucosa’s fragility, ease of bruising, and delayed wound healing also places limitations on dental treatment. Endodontic brackets, although highly polished and smooth to the touch, have sharp edges or have stainless steel ligatures and complex spring mechanisms which can abrade mucosal tissue. Orthodontic appliances should be smooth and relatively simple in design to prevent abrasion of the tongue and mucosa. Considerations of moment to force ratios, rate of bone resorption, tooth mobility and remodeling time are also important factors in treating these patients. Because of the problem with tissue repair (slow healing after extraction, slow forming new bone) suboptimal tissue responses should be expected.

Conclusions:
There are special considerations in treating the EDS dental patient. Our data shows that dental findings greatly vary among the EDS groups. EDS patients exhibit a high incidence of TMJ dislocation and a high incidence of TMD related pain and noise, particularly among those with types I and II. Orthodontic treatment is not shown to be different in length of treatment, but the experience of dental treatment appears to be more difficult in EDS patients. Whether it be TMJ symptoms or periodontal disease, there is a pronounced difference between the treatment concerns for an EDS patient and that of the rest of the population. Patients diagnosed with EDS type I and II should be treated with special care. Each type of EDS has characteristic dental manifestations which affect orthodontic treatment. The dental profession should recognize the dentofacial implications of EDS and provide the appropriate information and maintenance for these patients. Conservative treatment is certainly desirable. Proper management of these patients should strive to provide comfort while living with the syndrome.

We thank the EDNF for their cooperation and help.

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