Etiopathogenesis of parafunctional habits of the stomatognathic system.
A broad consensus does exist among main authors on the importance of parafunctional habits in the etiopathogenesis of temporomandibular disorders (TMD). Mechanisms through which an intense parafunctional activity determined a pathological effect on the temporomandibular joints (TMJs) and their related structures have still not been definitively clarified; nevertheless, before investigating those mechanisms, it's useful to study predisposing, triggering and/or worsening factors of parafunctions themselves. At present the theory, once widely accepted, according to which occlusal interferences can trigger a muscular hyperactivity through the activation of periodontal receptors, has lost a lot of credit. Recently, the hypothesis that bruxism and other parafunctions have a central etiology has become more and more accepted. In such a context, the role of the psychic component assumes a strong relevance, particularly for its relation with the limbic system, which is the part of the central nervous system (CNS) that regulates emotions. Such a hypothesis is confirmed by clinical practice, but it doesn't explain why some patients have reported a worsening of parafunctional activities after occlusal adjustment. The aim of this study is to investigate this issue through a critical review of the literature, indicating how the 2 theories might be complementary for the development and worsening of a parafunctional habit. From this review, despite the number of clinical opinions, there emerges a lack of methodologically appropriate associative works and controlled clinical trials which consent to clarify the effective importance of psychic and/or occlusal factors in the etiopathogenesis of parafunctional habits.
Manfredini
D
D
Section of Prosthetic Dentistry, Department of Neuroscience, Unit of Dental Prosthesis, CLOPD, University of Pisa, Pisa, Italy.
Landi
N
N
Romagnoli
M
M
Cantini
E
E
Bosco
M
M
D000328:Adult; D001007:Anxiety / Q000150:complications; D002012:Bruxism / Q000150:complications* / Q000503:physiopathology / Q000523:psychology / Q000628:therapy; D002675:Child, Preschool; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008032:Limbic System / Q000503:physiopathology; D008297:Male; D008410:Masticatory Muscles / Q000294:innervation / Q000503:physiopathology; D008954:Models, Biological; D008960:Models, Psychological; D009259:Nail Biting / Q000009:adverse effects* / Q000523:psychology; D019558:Occlusal Adjustment; D017288:Pain Threshold; D013315:Stress, Psychological / Q000150:complications; D013705:Temporomandibular Joint Disorders / Q000209:etiology* / Q000503:physiopathology