Association between local mechanical factors and orofacial pain: survey in the community

Prevalence of awake bruxism in the adult population: a systematic review and meta-analysis

OBJECTIVES

To evaluate the prevalence of awake bruxism (AB) in the adult population.

MATERIALS AND METHODS

Six main electronic databases and three sources of grey literature were searched to identify cross-sectional studies in which AB was assessed. The studies were independently selected by two reviewers in two phases, based on their eligibility criteria. The first one consisted of reading titles and abstracts, and the second one involved reading the full articles. The study quality assessment was obtained by using the "Joanna Briggs Institute Critical Appraisal Checklist for Studies Reporting Prevalence Data", and the "R Statistics" software was used to perform meta-analyses.

RESULTS

Seventeen out of 3086 identified studies were included. None of the studies scored high in methodological quality across all 9 items of the JBI checklist. However, "the use of valid methods to identify pathology" and "appropriate statistical analysis" were considered to have high methodological quality in all the studies. The overall pooled prevalence of the meta-analysis was 15.44% (99% confidence interval: 10.81 to 20.72%) and there was no difference for sex, sampling method and according to consensus-based classification.

CONCLUSIONS

The prevalence of AB in adults was low. There was substantial methodological variability, which highlights the need for standardized guidelines.

CLINICAL RELEVANCE

Prevalence data are useful for raising patients' and clinicians' awareness of the AB. Moreover, since AB can lead to possible pain and overload of the stomatognathic system, this knowledge can also guide dentists to achieve an early diagnosis of AB and to provide appropriate care management.

Involvement of Oxidative Stress and Nutrition in the Anatomy of Orofacial Pain

Pain is a very important problem of our existence, and the attempt to understand it is one the oldest challenges in the history of medicine. In this review, we summarize what has been known about pain, its pathophysiology, and neuronal transmission. We focus on orofacial pain and its classification and features, knowing that is sometimes purely subjective and not well defined. We consider the physiology of orofacial pain, evaluating the findings on the main neurotransmitters; in particular, we describe the roles of glutamate as approximately 30-80% of total peripheric neurons associated with the trigeminal ganglia are glutamatergic. Moreover, we describe the important role of oxidative stress and its association with inflammation in the etiogenesis and modulation of pain in orofacial regions. We also explore the warning and protective function of orofacial pain and the possible action of antioxidant molecules, such as melatonin, and the potential influence of nutrition and diet on its pathophysiology. Hopefully, this will provide a solid background for future studies that would allow better treatment of noxious stimuli and for opening new avenues in the management of pain.

Sigma-1 receptors and progesterone metabolizing enzymes in nociceptive sensory neurons of the female rat trigeminal ganglia: A neural substrate for the antinociceptive actions of progesterone

Orofacial pain disorders are predominately experienced by women. Progesterone, a major ovarian hormone, is neuroprotective and antinociceptive. We recently reported that progesterone attenuates estrogen-exacerbated orofacial pain behaviors, yet it remains unclear what anatomical substrate underlies progesterone's activity in the trigeminal system. Progesterone has been reported to exert protective effects through actions at intracellular progesterone receptors (iPR), membrane-progesterone receptors (mPR), or sigma 1 receptors (Sig-1R). Of these, the iPR and Sig-1R have been reported to have a role in pain. Progesterone can also have antinociceptive effects through its metabolite, allopregnanolone. Two enzymes, 5α-reductase and 3α-hydroxysteroid dehydrogenase (3α-HSD), are required for the metabolism of progesterone to allopregnanolone. Both progesterone and allopregnanolone rapidly attenuate pain sensitivity, implicating action of either progesterone at Sig-1R and/or conversion to allopregnanolone which targets GABAA receptors. In the present study, we investigated whether Sig-1 Rs are expressed in nociceptors within the trigeminal ganglia of cycling female rats and whether the two enzymes required for progesterone metabolism to allopregnanolone, 5α-reductase and 3α-hydroxysteroid dehydrogenase, are also present. Adult female rats from each stage of the estrous cycle were rapidly decapitated and the trigeminal ganglia collected. Trigeminal ganglia were processed by either fluorescent immunochemistry or western blotting to for visualization and quantification of Sig-1R, 5α-reductase, and 3α-hydroxysteroid dehydrogenase. Here we report that Sig-1Rs and both enzymes involved in progesterone metabolism are highly expressed in a variety of nociceptive sensory neuron populations in the female rat trigeminal ganglia at similar levels across the four stages of the estrous cycle. These data indicate that trigeminal sensory neurons are an anatomical substrate for the reported antinociceptive activity of progesterone via Sig-1R and/or conversion to allopregnanolone.

Anatomical Study of the Innervation of the Masseter Muscle and Its Correlation with Myofascial Trigger Points

Background and Purpose

Myofascial pain syndrome (MPS) is widely prevalent in the general population; some reports estimate its prevalence ranges from 9 to 85%. Among the different locations where MPS may arise, pain related to the masseter muscle is referred as masticatory myofascial pain. MPS is characterized by myofascial trigger points (MTPs), which represent tender anatomical areas of a muscle where painful symptoms are elicited whenever stimulated. Previous publications have found MTPs to coincide with neuromuscular junctions at the motor end plate, at the innervation zone (IZ). Our study aimed to describe the innervation of the masseter muscle and relate it to clinically described myofascial trigger points (MTPs).

Materials and Methods

We mapped the nerve fiber distribution into the masseter muscles from 16 cadavers by anatomical dissection. We divided the muscle into six regions, three superior (I–III) and three inferior (IV–VI), and classified the nerve’s branches distribution according to these predetermined areas. Statistical analyses was made by Poisson distribution and logarithm link function followed by Bonferroni multiple comparisons (P<0.05).

Results

All six areas received branches from the masseteric nerve. Areas I and II (upper posterior and upper intermediate, respectively) had a significant higher number of nerve entries as compared to the remaining areas.

Conclusion

The penetration areas of the masseteric nerve have been established and MTPs are found in the innervation zones, clinicians should focus initially on the regions of the penetration points, for diagnostics and therapeutic measures, such as injections, dry needling and soft tissue interventions. Anatomical study of nerve supply to the masseter muscle can provide useful additional knowledge to further understanding masticatory myofascial pain and to direct therapeutic interventions and diagnostic studies of temporomandibular junction dysfunction.

Perceived Practitioner Barriers to the Management of Orofacial Pain in the Kingdom of Saudi Arabia: A Cross-sectional Study

Background:

Orofacial Pain (OFP) is a group of non-dental painful conditions affecting the oral cavity and facial area.

Objectives:

The objective of this study was to explore which barriers to manage the patient with chronic OFP as perceived by general dentists versus dental specialists and to investigate whether if professionals with degrees from their home country versus another country or number of years of professional experience differ in their perceptions.

Methods:

A closed-end questionnaire was hand-delivered to 600 participants [300 general dentists and 300 dental specialists] in four major provinces in Saudi Arabia. Demographic data were expressed as frequency. Proportional t-tests and chi-square tests were used to analyse intergroup differences. Statistical significance for all analyses was set at P-value < 0.05.

Results:

Overall, the response rate was 56.6% (340/600). Around two-thirds of the participants were general dentists (60.9%), while the remainder were dental specialists (39.1%). There was an obvious consensus by the participants that “Low payment/reimbursement” and “Lack of OFP knowledge” were among the most common barriers (85% and 83.5%, respectively). In contrast, “Legal risks” were the least frequently reported factor (38.8%). The most commonly reported barrier by general dentists was “Shortage of patients/lack of demand;” this was significantly different from the experience of dental specialists (87% vs. 72.2%; P- value < 0.01). In terms of the country of graduation or years of experience, there were no significant differences.

Conclusion:

The study demonstrates the existence of many significant barriers other than OFP knowledge, such as reimbursement, facility and demand that could present obstacles and challenges to the management of OFP by general dentists and dental specialists. Most participants believed that dentists should manage this condition and that OFP courses should be included in the dental school curriculum.

Persistent dentoalveolar pain disorder: A putative intraoral chronic overlapping pain condition

Chronic overlapping pain conditions (COPCs) are conditions that share several clinical characteristics and symptomatology, are usually considered idiopathic in nature, and are frequently comorbid. Currently, there are no established inclusion criteria to determine which conditions should be included under this umbrella term despite different systems proposed. Persistent dentoalveolar pain disorder (PDAP), also referred to as atypical odontalgia and thought to be a component of persistent idiopathic facial pain, is a chronic pain condition that manifests as a persistent tooth pain or pain over a dentoalveolar site formerly occupied by a tooth in the absence of detectable pathology during clinical or radiological examination. PDAP is considered idiopathic in nature, and its pathophysiological mechanisms are not fully understood. Our objective was to investigate whether PDAP fits the conceptual paradigm of COPC given its characteristics and commonalities with other COPC, based on published literature identified through a scoping review. We found that PDAP fits 16 out of 18 common characteristics among COPCs, and based on this finding, we discuss the implications of PDAP being considered a COPC.

Sex, Gender, and Orofacial Pain

This review examines gender prevalence in orofacial pain to elucidate underlying factors that can explain such differences. This review highlights how gender affects (1) the association of hormonal factors and pain modulation; (2) the genetic aspects influencing pain sensitivity and pain perception; (3) the role of resting blood pressure and pain threshold; and (4) the impact of sociocultural, environmental, and psychological factors on pain.

Risk Factors of Orofacial Pain: A Population-Based Study in West Java Province, Indonesia

Background:

The management of orofacial pain in Indonesia has not been well performed, which consequently led to an increase in the orofacial pain occurrences and a decreased quality of life. One of the possible reasons for this particular matter is the lack of evaluation on the risk factors that might induce orofacial pain in some individuals.

Objective:

The objective of the current study was to evaluate the risk factors of orofacial pain on productive age population in West Java province, Indonesia.

Methods:

One thousand and fifty-six participants (522 males; 534 females) were recruited for the study. A questionnaire that consists of demographic questions and questions evaluating several assumed risk factors for orofacial pain was used in a single interview. All data was analyzed by using Chi Square test to test the significance, Odds Ratio (OR), as well as Relative Risk (RR) by using SPSS version 23 (IBM Statistic, USA).

Results:

The result of the current study revealed that bruxism (p<0.01), daytime clenching (p<0.01), and unilateral chewing (p<0.01) were significantly related to the occurrence of orofacial pain. It was also found that participants who performed multitude of heavy liftings at work have an increased risk (RR=1.19: 95% CI: 1.04 – 1.35) of having orofacial pain compared to those who do not.

Conclusion:

Risk factors for the occurrence of orofacial pain on productive age population in Indonesian sample consisted of oral parafunctional habits and non-parafunctional habits, such as heavy lifting. Further study in this particular topic is of importance.

Factors associated with mucosal pain in patients with partial removable dental prostheses

The aim of this study was to investigate factors associated with mucosal pain in patients with partial removable dental prostheses (PRDPs). In this hospital-based cross-sectional study, 333 patients wearing 500 PRDPs (mean age 71·4 years, men 33·3%) were consecutively recruited from prosthetic clinic of a dental hospital in Japan. Subjects rated pain intensity and frequency of denture-bearing mucosa. An examiner recorded age, gender and systemic diseases as well as dental, mucosa, denture, sensory, behavioural- and psychological-related characteristics that were possibly associated with the mucosal pain. Multivariate analyses were performed to analyse factors related to mucosal pain. Pain intensity was rated as more than score 0 (presence) in 34·2% (171/500) PRDPs, and pain was experienced after denture delivery in 42·8% (214/500) PRDPs. Logistic regression analyses showed that younger age, mucosal damage, poor mucosal condition, bone prominence, poor residual ridge, higher pain sensitivity, presence of awake bruxism, perception of oral dryness, interim denture wear and high number of missing teeth were significant independent predictors for the presence of the mucosal pain intensity and/or frequency (P < 0·05). Multiple factors are associated with mucosal pain in patients with PRDPs. Oral mucosal characteristics, age, pain sensitivity and behavioural factors seem to be more critical for mucosal pain than distribution of missing teeth and number of abutment teeth.

The Association Between Psychological Factors and Orofacial Pain and Its Effect on Quality of Life: A Hospital Based Study

OBJECTIVE

To examine the hypothesis that psychological factors of psychological distress and perception of unhappiness in childhood are associated with self reported orofacial pain and to examine whether such patients have a poorer perception of their oral health related quality of life and if so then to what extent.

MATERIALS AND METHODS

A cross-sectional hospital based study was conducted in Hitkarini Dental College and Hospital, Jabalpur amongst 400 cases and 400 controls. Patients were included based on Locker and Slade's criteria. Patients were asked to complete 27 items Questionnaire which included the General Health Questionnaire to assess for psychological distress and Oral Health Impact Profile-14 for evaluating impact on quality of life. Bivariate and logistic regression analyses were performed to determine the degree of association between psychological factors, unhappy childhood and quality of life. P-value of less than 0.05 was considered statistically significant.

RESULTS

An increased propensity to report orofacial pain was seen for those individuals with higher levels of Psychological Distress and with perception of Unhappiness in Childhood. These individuals also reported with poorer perception of their oral health related Quality of Life.

CONCLUSION

The present study has shown relationship between Orofacial Pain, Quality of Life and Psychological Factors.

Orofacial pain and headache: a review and look at the commonalities

Headache and facial pain - in particular, temporomandibular disorders (TMDs) - are very prevalent conditions in the general population. TMDs are defined as a collection of symptoms and signs involving masticatory muscles, the temporomandibular joints (TMJs), or both. The pain reported by TMD patients is typically located in the muscles of mastication, in the preauricular area, or in the TMJs. In many cases, headaches and facial pain will occur in the same patient. Much of the research relative to the relationship of these disorders focuses on statistics of association and prevalence data. This review will provide a brief description of the types and classifications of orofacial pains (OFPs), as well as point to relevant research describing the commonalities and potential comorbid nature of these maladies. Finally, several recent papers describing morphologic changes to the brain in headache and TMD individuals will be discussed in an effort to stimulate further research into the potential common pathophysiologic mechanism that may explain the comorbid nature of these disorders.

Self-Reported Facial Pain in UK Biobank Study: Prevalence and Associated Factors

Objectives

To determine the prevalence of facial pain and to examine the hypothesis that symptoms are associated with socio-demographic, dental, adverse psychological factors and pain elsewhere in the body.

Material and Methods

Cross-sectional population data were obtained from UK Biobank (www.ukbiobank.ac.uk/) study which was conducted in 2006 - 2010 and recruited over 500,000 people.

Results

The overall prevalence of facial pain (FP) was 1.9% (women 2.4%, men 1.2%) of which 48% was chronic. The highest prevalence was found in the 51 - 55 age group (2.2%) and the lowest in the 66 - 73 age group (1.4%). There was a difference in prevalence by ethnicity (0.8% and 2.7% in persons reporting themselves as Chinese and Mixed respectively). Prevalence of FP significantly associated with all measures of social class with the most deprived and on lowest income showing the highest prevalence (2.5% and 2.4% respectively). FP was more common in individuals who rated themselves as extremely unhappy, had history of depression and reported sleep problems. Smoking associated with increase in reporting FP while alcohol consumption had inverse association. FP associated with history of painful gums, toothache and all types of regional pain.

Conclusions

This is the largest ever study to provide estimates of facial pain prevalence. It demonstrates unique features (lower prevalence than previously reported) and common features (more common in women) and confirms multifactorial aetiology of facial pain. Significant association with psychological distress and a strong relationship to pain elsewhere in the body suggests that aetiology is not specific to this regional pain.

Persistent orofacial muscle pain

The pathophysiology of persistent orofacial myalgia has been the centre of much controversy. In this article we suggest a novel descriptive term; 'persistent orofacial muscle pain' (POMP) and review current evidence that supports the hypothesis that the induction of POMP involves the interplay between a peripheral nociceptive source in muscle, a faulty central nervous system component and decreased coping ability. In this context it is widely accepted that a complex interaction of variable intrinsic and extrinsic factors act to induce POMP and dysfunction.

Oral parafunctions as risk factors for diagnostic TMD subgroups

The frequency of diurnal clenching and/or grinding and nail-biting habits was assessed in patients affected by temporomandibular disorders (TMDs) and in healthy controls in order to investigate the possible association between these oral parafunctions and different diagnostic subgroups of TMDs. The case group included 557 patients (127 men, mean age +/- SD = 34.5 +/- 15.4 years; 430 women, mean age +/- SD = 32.9 +/- 14.1 years) affected by myofascial pain or disc displacement or arthralgia/arthritis/arthrosis. The control group included 111 healthy subjects (55 men, mean age +/- SD = 37 +/- 15.2 years; 56 women, mean age +/- SD = 38.2 +/- 13.8 years). Multinomial logistic regression analysis was used to assess the association between oral parafunctions and TMDs, after adjusting for age and gender. Daytime clenching/grinding was a significant risk factor for myofascial pain (odds ratio (OR) = 4.9, 95% confidence interval (CI): 3.0-7.8) and for disc displacement (OR = 2.5, 95% CI: 1.4-4.3), nail biting was not associated to any of the subgroups investigated. Female gender was a significant risk factor for myofascial pain (OR = 3.8; 95% CI: 2.4-6.1), whereas the risk factor for developing disc displacement decreased with ageing. No association was found between gender, age and arthralgia/arthritis/arthrosis.

Twenty-year cohort study of health gain from orthodontic treatment: temporomandibular disorders

INTRODUCTION

Temporomandibular disorder (TMD) is a common condition. Studies of TMD in relation to orthodontic treatment did not show an association, but longitudinal studies from adolescence to adulthood are lacking. The aim of this study was to investigate the relationship between orthodontic treatment and TMD with a longitudinal study design.

METHODS

This prospective cohort study was conducted in South Wales, United Kingdom. The baseline investigation was carried out in 1981 and involved children aged 11 to 12 years (n = 1018). Follow-up investigations were done in 1984 (n = 792), 1989 (n = 456), and 2000 (n = 337).

RESULTS

Overall TMD prevalence increased from the baseline (3.2%) to age 19 to 20 (17.6%) and decreased by age 30 to 31 (9.9%). TMD prevalence was higher in females at all follow-up points, except the baseline. Overall, incidences of TMD were 11.9%, 11.5%, and 6.0% at the first, second, and last follow-ups, respectively. Females were more likely to develop TMD than males (hazard ratio [HR], 2.1; 95% CI, 1.3 and 3.3), and those with high self-esteem were less likely to develop TMD (HR, 0.6; 95% CI, 0.4 and 0.8). There was no association between orthodontic treatment and new TMD onset. The incidences of persistent TMD were 20.0%, 34.9%, and 28.0% at the first, second, and last follow-ups, respectively. Females were more likely to have persistent TMD than males (HR, 2.5; 95% CI, 1.0 and 6.1). There was no association between orthodontic treatment and persistent TMD. The only significant predictors of TMD in adults aged 30 to 31 were female sex (odd ratio, 3.0; 95% CI, 1.1 and 8.2) and TMD in adolescence (odds ratio, 4.5; 95% CI, 2.0 and 10.0).

CONCLUSIONS

Orthodontic treatment neither causes nor prevents TMD. Female sex and TMD in adolescence were the only predictors of TMD in young adulthood.

Toothache and associated factors in Brazilian adults: a cross-sectional population-based study

BACKGROUND

Toothache is a dental public health problem and one of the predictors of dental attendance and it is strongly associated with the life quality of individuals. In spite of this, there are few population-based epidemiological studies on this theme.

OBJECTIVE

To estimate the prevalence of toothache and associated factors in adults of Lages, Southern Brazil.

METHODS

A cross-sectional population-based study was carried out in a sample of 2,022 adults aged 20 to 59 years living in the urban area of a medium sized city in Southern Brazil. A questionnaire including socioeconomic, demographic, smoking, alcohol, and use of dental service variables was applied at adults household. Toothache occurred six months previous of the interview was considered the outcome. Poisson regression analyses were performed following a theoretical hierarchical framework. All analysis was adjusted by the sample design effect.

RESULTS

The response rate was 98.6%. The prevalence of toothache was 18.0% (95% CI 16.0; 20.1). The following variables were associated with toothache after adjustment: female (PR = 1.3 95% CI 1.3; 2.0), black skin colour vs. whites (PR = 1.5 95% CI 1.1, 1.9), low per capita income (PR = 1.7 95% CI 1.2, 2.3), smokers (PR = 1.5 95% CI 1.2, 1.9) and those who reported alcohol problems (PR = 1.4 95% CI 1.1; 1.9). To be 40 years of age (PR = 0.5 95% CI 0.4, 0.7) and use dental service in the last year (RR = 0.5 95% CI 0.4, 0.6) were protective factors for toothache.

CONCLUSION

The prevalence of toothache in adults of Lages can be considered a major problem of dental public health.

Orthodontic Treatment, Genetic Factors and Risk of Temporomandibular Disorder

Traditionally, four groups of factors have been identified in the etiology of temporomandibular disorder (TMD): anatomical variation in the masticatory system; psychosocial characteristics; pain in other body regions; and demographics. Orthodontic treatment has been variously cited both as a protective and harmful factor in TMD etiology. Recently, a search has begun for a genetic influence on TMD etiology. Genetic markers can be of additional value in identifying gene-environment interactions, that is, isolating population sub-groups, defined by genotype in which environmental influences play a relatively greater or lesser etiological role. This paper reviews concepts and study design requirements for epidemiological investigations into TMD etiology. Findings are presented from a prospective cohort study of 186 females that illustrate an example of gene-environment interaction in TMD onset. Among people with a variant of the gene encoding catechol-O-methyl-transferase, an enzyme associated with pain responsiveness, risk of developing TMD was significantly greater for subjects who reported a history of orthodontic treatment compared with subjects who did not (P=0.04). While further studies are needed to investigate TMD etiology, this genetic variant potentially could help to identify patients whose risk of developing TMD is heightened following orthodontic treatment, hence serving as a risk marker useful in planning orthodontic care.

Freqüência de relatos de parafunções nos subgrupos diagnósticos de DTM de acordo com os critérios diagnósticos para pesquisa em disfunções temporomandibulares (RDC/TMD)

INTRODUÇÃO: as disfunções temporomandibulares (DTM) podem ser definidas como um conjunto de condições dolorosas e/ou disfuncionais, que envolvem os músculos da mastigação e/ou as articulações temporomandibulares (ATM). Um dos meios usados para o diagnóstico é o "Critério Diagnóstico para Pesquisa em Disfunções Temporomandibulares" (RDC/TMD). Hábitos parafuncionais são aqueles não relacionados à execução das funções normais do sistema estomatognático. O bruxismo é caracterizado por atividade parafuncional noturna involuntária dos músculos mastigatórios, enquanto o apertamento dentário é considerado uma parafunção diurna envolvendo esta musculatura, embora possa ocorrer também à noite. OBJETIVOS: o objetivo do presente estudo foi avaliar a freqüência do relato de parafunções orais diurna e/ou noturna em pacientes com DTM nos diferentes subgrupos diagnósticos do RDC/TMD. METODOLOGIA: foram utilizados dados provenientes de 217 pacientes que procuraram tratamento na Clínica de DTM e Dor Orofacial da Faculdade de Medicina de Petrópolis, sendo avaliados através do questionário e exame físico que compõem o RDC/TMD. RESULTADOS: dos 182 pacientes com DTM estudados, 76,9% relataram algum tipo de parafunção, podendo ser diurna, noturna ou a associação de ambas. A parafunção diurna foi a mais freqüentemente relatada entre os subgrupos de DTM, sendo encontrada em 64,8% dos casos contra 55,5% dos casos com relato de bruxismo. O relato de ambas as parafunções foi constatado em 43,4% dos pacientes com DTM. CONCLUSÕES: considerando cada subgrupo diagnóstico, os relatos de parafunções diurna e noturna foram mais freqüentes nos pacientes com dor miofascial.

Association between sleep bruxism and temporomandibular disorders: a polysomnographic pilot study

The aim of this study was to verify the association between sleep bruxism (SB) and temporomandibular disorders (TMD) in a sample of 14 TMD patients and 12 healthy control subjects. All participants were evaluated using a clinical questionnaire, visual analog scale (VAS) for TMJ/muscle palpation, and by functional examination. The experimental group was divided into three TMD subgroups: joint sounds and pain, muscular tenderness, and mixed diagnosis. All participants underwent polysomnographic recording (PSG). A second clinical examination was then carried out to verify the relationship between rhythmic masticatory muscle activity and pain/tenderness on the following morning. The experimental and control groups presented VAS mean scores of 36.85 +/- 23.73 mm and 0 mm, respectively. The presence of SB was neither associated with TMD (p > 0.05) nor with pain on palpation (p > 0.05). Further research with a more representative sample of each TMD subgroup is necessary to elucidate its interaction with SB.

The Role of Tooth-Grinding in the Maintenance of Myofascial Face Pain: A Test of Alternate Models

OBJECTIVE

While mechanisms of myofascial face pain are poorly understood, bruxism has been implicated in the maintenance of this painful disorder. This study evaluates whether evidence of one aspect of bruxism, tooth-grinding, is positively associated with pain severity, as predicted by a psychophysiological model, or negatively associated, as predicted by an adaptation model of face pain.

PATIENTS

Participants were 51 women who met Research Diagnostic Criteria for the myofascial subtype of temporomandibular disorder.

OUTCOME MEASURES

Tooth-grinding was quantified by changes in microwear features of the molar teeth over 2 weeks. Palpated pain severity was quantified on an 11-point scale in response to palpation of the skin overlying the masseter and temporalis muscles bilaterally. Other measures included validated scales of spontaneous pain severity, stress, distress, and psychological symptoms. Association was quantified as Pearson correlation coefficients.

RESULTS

Data showed an inverse correlation (r = -0.37, P < 0.05) between palpated pain severity and the index of tooth wear, supporting the adaptation model. This correlation provided a weighted average of a strong effect (r = -0.80, P < 0.01) seen in those women reporting pain only the right side of their face with an effect that approximated zero in those reporting bilateral pain. Tooth wear measures were negatively associated with ratings of pain severity only over the right masseter.

DISCUSSION

While these data do not address the role of clenching, they cast serious doubt on the theory that myofascial face pain is maintained by tooth-grinding.

Signs and symptoms related to temporomandibular disorders—Follow-up of subjects with shortened and complete dental arches

OBJECTIVE

To assess prevalence of cardinal signs and symptoms related to temporomandibular disorders (TMD) in subjects with shortened dental arches and to clarify the individual course of these signs and symptoms.

METHODS

In this 9-year follow-up study, subjects with shortened dental arches (n=74) were compared with subjects with complete dental arches (n=72). Of three reported symptoms (pain, noises/clicking and restricted mobility of the lower jaw), and of two clinical signs (palpated clicking of the temporomandibular joint and restricted maximal mouth opening) estimates of mean scores were calculated by a mixed model. Suggested determinants for TMD (gender, time, bruxism, chewing side preference) were investigated by covariate analyses. Subjects with complete 9-year follow-up (shortened dental arches: n=42; complete dental arches: n=41) were described more detailed by frequency distributions, Pearson correlations of signs and symptoms, and fluctuation of the symptoms.

RESULTS

Covariate analyses using the mixed model revealed no significant differences between the shortened and the complete dental arch groups (p>0.05) with respect to symptoms and signs. Most prevailing effect was gender: females reported more frequently pain (p=0.05) and noises/clicking (p=0.03). Restricted mobility was significantly related with chewing side preference and bruxism habits (both: p=0.01). In both groups, subjects with complete 9-year follow-up had low prevalence of serious symptoms and signs and symptoms fluctuated without demonstrable correlation.

CONCLUSION

In this 9-year follow-up, subjects with shortened dental arches had similar prevalence, severity, and fluctuation of signs and symptoms related to TMD compared to subjects with complete dental arches.

Tiagabine May Reduce Bruxism and Associated Temporomandibular Joint Pain

Tiagabine is an anticonvulsant gamma-aminobutyric acid reuptake inhibitor commonly used as an add-on treatment of refractory partial seizures in persons over 12 years old. Four of the 5 cases reported here indicate that tiagabine might also be remarkably effective in suppressing nocturnal bruxism, trismus, and consequent morning pain in the teeth, masticatory musculature, jaw, and temporomandibular joint areas. Tiagabine has a benign adverse-effect profile, is easily tolerated, and retains effectiveness over time. Bed partners of these patients report that grinding noises have stopped; therefore, the tiagabine effect is probably not simply antinociceptive. The doses used to suppress nocturnal bruxism at bedtime (4-8 mg) are lower than those used to treat seizures.