Sleep and Orofacial Pain: Physiological Interactions and Clinical Management

Sleep and pain are both vital functions on which wellbeing, health, and life itself depend. These two complex states interact in several ways serving homeostasis, but they are also regulated by a well-orchestrated, multi-oscillatory mechanism characterizing the Circadian Timing System. This interaction, which benefits critical physiological challenges, is also clinically crucial, as it mutually affects sleep and pain-related disturbances. It impacts pathophysiological pathways and relevant clinical aspects of many disorders. Furthermore, therapeutic success is frequently dependent on the adequate management of this cycle. The relationship of sleep and pain is undoubtedly of major relevance for diagnosis and successful management of various health conditions and disorders

The effect of tooth clenching on the sensory and pain perception in the oro-facial region of symptom-free men and women

The aim of this study was (i) to examine the effect of light tooth contact as in diurnal tooth clenching on the tactile detection threshold (TDT), the filament-prick pain detection threshold (FPT) and the pressure pain threshold (PPT) in the oro-facial region and (ii) to examine the possible gender difference in this effect on the tactile and pain perception. Twenty healthy volunteers participated. The TDT and the FPT were measured by means of Semmes-Weinstein monofilaments, on the cheek skin (CS) overlying the masseter muscles (MM) and on the skin overlying the palm side of the thenar skin (TS). The PPT was measured at the central part of the MM using a pressure algometer. Each parameter was measured before and after keeping light tooth contact for 5 min (session 1) and after keeping the jaw relaxed for 5 min (session 2) as a control. Although there were no significant session effects on any of the parameters, there were significant effects of experimental condition on the TDT in both men and women (P < 0·001). Men had a significant higher FPT of the left CS (P < 0·05) and TS (P < 0·01) and a significant higher PPT of the MM than women (P < 0·001). These results illustrate that sensitivity to pain (FPT, PPT) was higher in women than in men. Although there were no significant gender differences in habituation of sensory perception, the increase of TDT after clenching/no clenching was larger in women, which warrants further study

Clinical Management of Implant Prostheses in Patients with Bruxism

There is general agreement that excessive stress to the bone-implant interface may result in implant overload and failure. Early failure of the implant due to excessive loading occurs shortly after uncovering the implant. Excess load on a final restoration after successful implant integration can result in physical failure of the implant structure. Many clinicians believe that overload of dental implants is a risk factor for vertical peri-implant bone loss and/or may be detrimental for the suprastructure in implant prostheses. It has been documented that occlusal parafunction, such as, bruxism (tooth grinding and clenching) affects the outcome of implant prostheses, but there is no evidence for a causal relation between the failures and overload of dental implants. In spite of this lack of evidence, often metal restorations are preferred instead of porcelain for patients in whom bruxism is presumed on the basis of tooth wear. The purpose of this paper is to discuss the importance of the occlusal scheme used in implant restorations for implant longevity and to suggest a clinical approach and occlusal materials for implant prostheses in order to prevent complications related to bruxism

Experimental low-level jaw clenching inhibits temporal summation evoked by electrical stimulation in healthy human volunteers

Objective To examine the effect of low-level jaw clenching on temporal summation in healthy volunteers. Design In 18 healthy volunteers, the pain intensities evoked at the masseter muscle and the hand palm by the first and last stimuli in a train of repeated electrical stimuli (0.3 or 2.0 Hz) were rated using 0-100 mm visual analogue scales (VAS), in order to evaluate temporal summation before and after three types of jaw-muscle tasks: low-level jaw clenching, repetitive gum chewing and mandibular rest position. A set of concentric surface electrodes with different diameters (small and large) was used for the electrical stimulation. Results The temporal summation evoked by the large diameter electrode with 2.0 Hz stimulation decreased significantly both on the masseter and the hand after low-level clenching (P > 0.03), but did not show any significant change after the other tasks (P > 0.23). The VAS score of the first stimulation did not show any significant changes after low-level clenching (P > 0.57). Conclusions Experimental low-level jaw clenching can inhibit pain sensitivity, especially temporal summation. Low-level jaw clenching can modify pain sensitivity, most likely through the central nervous system. The findings suggest that potential harmful low-level jaw clenching or tooth contacting could continue despite painful symptoms, e.g., temporomandibular disorders

Modulation of neck muscle activity induced by intra-oral stimulation in humans

Objective: To investigate the effect of painful electrical stimuli applied to intra-oral tissues around the teeth on the neck muscle activity in healthy humans. Methods: Electromyographic (EMG) responses of the dorsal neck muscles evoked by intra-oral electrical stimulation were recorded before and after local anesthesia to the stimulus site in 17 healthy volunteers. Results: Inhibition of dorsal neck muscle EMG activities on average 80% compared to baseline level was observed with a latency around 50. ms after the electrical stimulation before anesthesia, and the EMG activity inhibition decreased after anesthesia of the intra-oral stimulus site. The perceived intensity of the electrical stimuli as scored on a visual analogue scale (VAS) was 6.1. ±. 0.4. cm before anesthesia and 1.5. ±. 0.2. cm after anesthesia. Conclusion: Intra-oral stimulation can inhibit neck muscle activity. This modulation might be attributed mainly to nociceptive afferent nerves however, non-nociceptive fibers could also be responsible. Significance: Intra-oral information including nociceptive activity can inhibit neck muscle activity. From a clinical viewpoint, the present findings demonstrate the neural connectivity between the trigeminal region and the cervical region raising the possibility that orofacial pain conditions could influence head, neck and shoulder activity

Methodological quality of a systematic review on physical therapy for temporomandibular disorders: influence of hand search and quality scales

The validity of a systematic review depends on completeness of identifying randomised clinical trials (RCTs) and the quality of the included RCTs. The aim of this study was to analyse the effects of hand search on the number of identified RCTs and of four quality lists on the outcome of quality assessment of RCTs evaluating the effect of physical therapy on temporomandibular disorders. In addition, we investigated the association between publication year and the methodological quality of these RCTs. Cochrane, Medline and Embase databases were searched electronically. The references of the included studies were checked for additional trials. Studies not electronically identified were labelled as “obtained by means of hand search”. The included RCTs (69) concerning physical therapy for temporomandibular disorders were assessed using four different quality lists: the Delphi list, the Jadad list, the Megens & Harris list and the Risk of Bias list. The association between the quality scores and the year of publication were calculated. After electronic database search, hand search resulted in an additional 17 RCTs (25%). The mean quality score of the RCTs, expressed as a percentage of the maximum score, was low to moderate and varied from 35.1% for the Delphi list to 54.3% for the Risk of Bias list. The agreement among the four quality assessment lists, calculated by the Interclass Correlation Coefficient, was 0.603 (95% CI, 0.389; 0.749). The Delphi list scored significantly lower than the other lists. The Risk of Bias list scored significantly higher than the Jadad list. A moderate association was found between year of publication and scores on the Delphi list (r = 0.50), the Jadad list (r = 0.33) and the Megens & Harris list (r = 0.43)

PAIN ASSOCIATED WITH TEMPOROMANDIBULAR DISORDERS

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Sommeil et douleur

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CLASSIFICATION OF OROFACIAL PAIN

© 2014 IASP Press. All rights reserved. This chapter outlines the main elements to consider in a taxonomic approach to orofacial chronic pain. The general principles for classification of chronic pain appear in the introduction to the classification of chronic pain by the International Association for the Study of Pain (IASP); readers interested in classification are referred to this pragmatic and seminal text. This chapter expresses its main lines of thought, especially in relation to orofacial pain states, and describes some recent developments.status: publishe

Dental and musculoskeletal pain

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