Tooth Clenching is More Frequent in Individuals With Increased Somatosensory Amplification

Objectives: Somatosensory amplification refers to the tendency to experience a somatic sensation as intense, noxious, and disturbing and has been related to bodily hypervigilance. Clinical experience suggests that individuals with an increased bodily hypervigilance also present a heightened occlusal hypervigilance.
Oral parafunctional behaviors are activities such as gum chewing, tooth clenching, nail/lip/cheek biting which go beyond physiological functioning, and could result in harmful effects on teeth and jaw muscles.
Daytime tooth clenching is an oral behavior characterized by repetitive tooth to tooth contacts determined by the contraction of the elevator muscles. This parafunction may serve to scan the intraoral environment in search of possible threats and may be more prevalent in individuals with heightened somatosensory amplification.
This study aimed to investigate whether oral parafunctional behaviors and in particular daytime tooth clenching are more frequent in individuals with heightened somatosensory amplification.
Methods: The Oral Behavior Checklist (OBC), the somatosensory amplification scale (SSAS), the State-Trait anxiety inventory (STAI), and the TMD (Temporomandibular Disorders) Screening Questionnaire were filled by 118 students (81 females, 31 males; mean age 25.5±5.1 years) at the University of Toronto through a web-survey. Two study groups with scores< 20^th (group A, 24 subjects) and>80^th (Group B, 27 subjects) percentile of the SSAS score distribution were constructed.
Results: Group B had greater OBC (22.7±10.7 vs 14.2±6.2, p=0.001) and trait anxiety (STAI, 50.5±10.9 vs 38.3 ± 6.6, p<0.001) scores than group A. Tooth clenching was more frequently reported by group B than group A (5.6±4.4 vs 3.3± 2.5, p=0.024). The self-reported incidence of pain in jaw or temple areas in the last 30 days was not different between groups (p=0.169).
Conclusions: Oral parafunctions and daytime tooth clenching are more frequently reported in individuals with increased somatosensory amplification. Clinicians should recognize individuals with altered somatosensory amplification to tailor their treatment strategies better.