Genetic Polymorphisms and Their Association With Temporomandibular Disorders

Genetic Polymorphisms and Their Association With Temporomandibular Disorders

Temporomandibular disorders (TMD) are the most common orofacial pain disorders of non-dental origin with the prevalence of 6.1-10.2%, and incidence of 3.9%. Observable pathology is mostly absent, and the etiology often remains unknown. Since some other painful conditions of unknown origin (eg. fibromyalgia), also imply genetic factors, the aim of the study is to investigate genetic predisposition in relation to the risk for TMD onset. This will be achieved through analysis of polymorphisms in the selected genes in TMD patients (DC/TMD) and matched control subjects. The possibility of involvement of specific polymorphisms in modulation of therapy response will also be investigated. The hypotheses: (I) the Single Nucleotide Polymorphism (SNPs) clustering will be dependent on presence or absence of TMD (comparison of patients with control subjects), and will possibly depend on source of pain, pain intensity, presence of bone changes, psychological features and previous orthodontic therapy, and (II) SNPs will influence the treatment response. Along with anamnestic and clinical examination and occlusal splint therapy, genomic DNA will be analyzed from the buccal swabs. Isolated DNA will be used for the determination of 19 polymorphisms of selected genes using Real-Time PCR method. The analysis of salivary oxidative stress markers and opiorphin will be also performed, as their relationship with TMD has been shown previously. This time, their concentration will be associated with polymorphisms in the promoters of genes responsible for their synthesis. The investigators expect to show that particular gene profile or group of SNPs represent a risk factor for TMD development. Innovative approach of the concept of determining the genetic predisposition for TMD has the potential for development of commercial genetic test with potential for risk estimation in relation to TMD onset. This could enable early interventions and active avoidance of environmental risk factors.

Inclusion Criteria:

• diagnosis of myofascial pain / arthralgia / painful disc displacement according to Diagnostic Criteria for Temporomandibular Disorders (DC/TMD)
• average pain in the last 10 days >30 mm on a Visual Analogue Scale
• pain duration of at least 3 months
• good oral hygiene
• presence of own natural teeth
• absence of any form of chronic pain in the orofacial region or in other regions of the body

Exclusion Criteria:

• other orofacial pain conditions including dental pain
• poor oral hygiene, gingivitis or periodontitis
• chronic medical conditions (diabetes, cardiovascular diseases, cancer, and autoimmune diseases) - - -
• neurological and psychiatric disorders
• pregnancy
• causes of headache, unrelated to TMD, listed in the International Classification of Headache Disorders