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Introduction: Inequity in access to healthcare in the United Kingdom can have a profound impact on people's ability to manage their health problems. Link work interventions attempt to overcome the socioeconomic and structural barriers that perpetuate health inequalities. Link workers are typically staff members without professional clinical qualifications who support patients to bridge the gap between services. However, little is currently known about how and why link work interventions might be effective. This realist review attempts to understand the contexts and resultant mechanisms by which link work interventions affect access to community healthcare services., Methods: The authors completed a systematic search of empirical literature in Embase, CINAHL, Medline, PsychInfo and SocIndex, as well as grey literature and CLUSTER searches. Context, mechanism and outcome (CMO) configurations were generated iteratively in consultation with an expert panel and grouped into theory areas., Results: Thirty-one eligible manuscripts were identified, resulting in nine CMO configurations within three theory areas. These pertained to adequate time in time-pressured systems; the importance of link workers being embedded across multiple systems; and emotional and practical support for link workers., Conclusion: Although link work interventions are increasingly utilised across community healthcare settings, the contexts in which they operate vary considerably, triggering a range of mechanisms. The findings suggest that careful matching of resources to patient need and complexity is important. It affords link workers the time to develop relationships with patients, embed themselves in local communities and referring teams, and develop knowledge of local challenges., Patient or Public Contribution: The team included people with lived experience of mental health conditions and a carer who were involved at all stages of the review., (© 2024 The Author(s). Health Expectations published by John Wiley & Sons Ltd.)

Background: Oral submucous fibrosis (OSF) is a chronic disease of the oral cavity that causes progressive constriction of the cheeks and mouth accompanied by severe pain and reduced mouth opening. OSF has a significant impact on eating and swallowing, affecting quality of life. There is an increased risk of oral malignancy in people with OSF. The main risk factor for OSF is areca nut chewing, and the mainstay of treatment has been behavioural interventions to support habit cessation. This review is an update of a version last published in 2008., Objectives: To evaluate the benefits and harms of interventions for the management of oral submucous fibrosis., Search Methods: We used standard, extensive Cochrane search methods. The latest search date was 5 September 2022., Selection Criteria: We considered randomised controlled trials (RCTs) of adults with a biopsy-confirmed diagnosis of OSF treated with systemic, locally delivered or topical drugs at any dosage, duration or delivery method compared against placebo or each other. We considered surgical procedures compared against other treatments or no active intervention. We also considered other interventions such as physiotherapy, ultrasound or alternative therapies., Data Collection and Analysis: We used standard Cochrane methods. Our primary outcomes were 1. participant-reported resumption of normal eating, chewing and speech; 2. change or improvement in maximal mouth opening (interincisal distance); 3. improvement in range of jaw movement; 4. change in severity of oral/mucosal burning pain/sensation; 5., Adverse Effects: Our secondary outcomes were 6. quality of life; 7. postoperative discomfort or pain as a result of the intervention; 8. participant satisfaction; 9. hospital admission; 10. direct costs of medication, hospital bed days and any associated inpatient costs for the surgical interventions. We used GRADE to assess certainty of evidence for each outcome., Main Results: We included 30 RCTs (2176 participants) in this updated review. We assessed one study at low risk of bias, five studies at unclear risk of bias and 24 studies at high risk of bias. We found diverse interventions, which we categorised according to putative mechanism of action. We present below our main findings for the comparison 'any intervention compared with placebo or no active treatment' (though most trials included habit cessation for all participants). Results for head-to-head comparisons of active interventions are presented in full in the main review. Any intervention versus placebo or no active treatment Participant-reported resumption of normal eating, chewing and speech No studies reported this outcome. Interincisal distance Antioxidants may increase mouth opening (indicated by interincisal distance (mm)) when measured at less than three months (mean difference (MD) 3.11 mm, 95% confidence interval (CI) 0.46 to 5.77; 2 studies, 520 participants; low-certainty evidence), and probably increase mouth opening slightly at three to six months (MD 8.83 mm, 95% CI 8.22 to 9.45; 3 studies, 620 participants; moderate-certainty evidence). Antioxidants may make no difference to interincisal distance at six-month follow-up or greater (MD -1.41 mm, 95% CI -5.74 to 2.92; 1 study, 90 participants; low-certainty evidence). Pentoxifylline may increase mouth opening slightly (MD 1.80 mm, 95% CI 1.02 to 2.58; 1 study, 106 participants; low-certainty evidence). However, it should be noted that these results are all less than 10 mm, which could be considered the minimal change that is meaningful to someone with oral submucous fibrosis. The evidence was very uncertain for all other interventions compared to placebo or no active treatment (intralesional dexamethasone injections, pentoxifylline, hydrocortisone plus hyaluronidase, physiotherapy). Burning sensation Antioxidants probably reduce burning sensation visual analogue scale (VAS) scores at less than three months (MD -30.92 mm, 95% CI -31.57 to -30.27; 1 study, 400 participants; moderate-certainty evidence), at three to six months (MD -70.82 mm, 95% CI -94.39 to -47.25; 2 studies, 500 participants; moderate-certainty evidence) and at more than six months (MD -27.60 mm, 95% CI -36.21 to -18.99; 1 study, 90 participants; moderate-certainty evidence). The evidence was very uncertain for the other interventions that were compared to placebo and measured burning sensation (intralesional dexamethasone, vasodilators). Adverse effects Fifteen studies reported adverse effects as an outcome. Six of these studies found no adverse effects. One study evaluating abdominal dermal fat graft reported serious adverse effects resulting in prolonged hospital stay for 3/30 participants. There were mild and transient general adverse effects to systemic drugs, such as dyspepsia, abdominal pain and bloating, gastritis and nausea, in studies evaluating vasodilators and antioxidants in particular., Authors' Conclusions: We found moderate-certainty evidence that antioxidants administered systemically probably improve mouth opening slightly at three to six months and improve burning sensation VAS scores up to and beyond six months. We found only low/very low-certainty evidence for all other comparisons and outcomes. There was insufficient evidence to make an informed judgement about potential adverse effects associated with any of these treatments. There was insufficient evidence to support or refute the effectiveness of the other interventions tested. High-quality, adequately powered intervention trials with a low risk of bias that compare biologically plausible treatments for OSF are needed. It is important that relevant participant-reported outcomes are evaluated., (Copyright © 2024 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.)

Objectives: Cardiovascular disease (CVD) is a major cause of mortality; periodontal disease (PD) affects up to 50% of the world's population. Observational evidence has demonstrated association between CVD and PD. Absent from the literature is a systematic review and meta-analysis of longitudinal cohort studies quantifying CVD risk in PD populations compared to non-PD populations. To examine the risk of incident CVD in people with PD in randomised controlled trials and longitudinal cohort studies., Material and Methods: We searched Medline, EMBASE and Cochrane databases up to 9th Oct 2019 using keywords and MeSH headings using the following concepts: PD, CVD, longitudinal and RCT study design. CVD outcomes included but were not restricted to any CVD, myocardial infarction, coronary heart disease (CHD) and stroke. Diagnosis method and severity of PD were measured either clinically or by self-report. Studies comparing incident CVD in PD and non-PD populations were included. Meta-analysis and meta-regression was performed to determine risk of CVD in PD populations and examine the effects of PD diagnosis method, PD severity, gender and study region., Results: Thirty-two longitudinal cohort studies were included after full text screening; 30 were eligible for meta-analysis. The risk of CVD was significantly higher in PD compared to non-PD (relative risk [RR]: 1.20, 95% CI: 1.14-1.26). CVD risk did not differ between clinical or self-reported PD diagnosis (RR = 0.97, 95% CI: 0.87-1.07,). CVD risk was higher in men (RR: 1.16, 95% CI: 1.08-1.25) and severe PD (RR: 1.25, 95% CI: 1.15-1.35). Among all types of CVD, the risk of stroke was highest (RR = 1.24; 95% CI:1.12-1.38), the risk of CHD was also increased (RR = 1.14; 95% CI:1.08-1.21)., Conclusion: This study demonstrated modest but consistently increased risk of CVD in PD populations. Higher CVD risk in men and people with severe PD suggests population-targeted interventions could be beneficial., (© 2020 The Authors. Clinical and Experimental Dental Research published by John Wiley & Sons Ltd.)

Background: Psychosocial risk factors associated with chronic orofacial pain are amenable to self-management. However, current management involves invasive therapies which lack an evidence base and has the potential to cause iatrogenic harm., Objectives: To determine: (a) whether self-management is more effective than usual care in improving pain intensity and psychosocial well-being and (b) optimal components of self-management interventions., Databases and Data Treatment: Cochrane Oral Health Group Trials Register, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, PsycINFO, WHO International Clinical Trials Registry Platform and Clinical Trials.gov were searched. Meta-analysis was used to determine effectiveness, and GRADE was used to rate quality, certainty and applicability of evidence., Results: Fourteen trials were included. Meta-analyses showed self-management was effective for long-term pain intensity (standardized mean difference [SMD] -0.32, 95% confidence interval [CI] -0.47 to -0.17) and depression (SMD -0.32, 95% CI -0.50 to -0.15). GRADE analysis showed a high score for certainty of evidence for these outcomes and significant effects for additional outcomes of activity interference (-0.29 95% CI -0.47 to -0.11) and muscle palpation pain (SMD -0.58 95% CI -0.92 to -0.24). Meta-regression showed nonsignificant effects for biofeedback on long-term pain (-0.16, 95% CI -0.48 to 0.17, p-value = 0.360) and depression (-0.13, 95% CI -0.50 to 0.23, p-value = 0.475)., Conclusions: Self-management interventions are effective for patients with chronic orofacial pain. Packages of physical and psychosocial self-regulation and education appear beneficial. Early self-management of chronic orofacial pain should be a priority for future testing., Significance: This systematic review provides clear evidence for effectiveness of combined biomedical and psychological interventions (incorporating self-management approaches) on long-term outcomes in the management of chronic orofacial (principally TMD) pain. Self-management should be a priority for early intervention in primary care in preference to invasive, irreversible and costly therapies. Further research is needed firstly to clarify the relative effectiveness of specific components of self-management, both individually and in conjunction, and secondly on outcomes in other types of chronic orofacial pains., (© 2019 European Pain Federation - EFIC®.)

Background: The aim of the study was to test the hypothesis that associations with specific stress systems [hypothalamic-pituitary-adrenal (HPA) and growth hormone (GH) axes] would increase as the number of unexplained disorders increased while accounting for the possible confounding effects of psychosocial factors., Methods: A cross-sectional study identified those reporting chronic widespread pain, irritable bowel syndrome, chronic orofacial pain and chronic fatigue. Of the 1315 subjects, disorder status was available for 1180 (89.7%), of whom 766 (64.9%) reported no disorders, 277 (23.5%) reported one and 137 (11.6%) reported two or more. Eighty subjects were sought from each group for assessment of HPA (morning 8:00 a.m. and evening 10:00 p.m. saliva, and post-dexamethasone serum cortisol levels) and GH [serum insulin-like growth factor 1 (IGF-1) level] axis function. Validated questionnaires informed current psychological state., Results: Two hundred twenty-seven subjects participated [79 (35%) with no disorders, 78 (34%) with one disorder and 70 (31%) with two or more disorders]. There were no significant associations (p < 0.05) between individual disorders or an increasing disorder load with any of the neuroendocrine levels measured: saliva/serum cortisol, IGF-1 and dehydroepiandrosterone. Psychosocial factors were independently associated with disorders and with an increasing disorder load: health anxiety p < 0.01, anxiety p < 0.01, depression p < 0.01, life events p = 0.03., Conclusion: Although previous studies have shown that stress axis function acts to moderate the risk of onset of some of these disorders, the present study shows that the degree of dysfunction is not correlated with a corresponding increasing load of disorders. The uncertainty surrounding the role of these biomarkers in the aetiology of unexplained disorders needs further investigation., (© 2013 European Pain Federation ‐ EFIC®)

Background: Composite filling materials have been increasingly used for the restoration of posterior teeth in recent years as a tooth-coloured alternative to amalgam. As with any filling material composites have a finite life-span. Traditionally, replacement was the ideal approach to treat defective composite restorations, however, repairing composites offers an alternative more conservative approach to the tooth structure where restorations are partly still serviceable. Repairing the restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement., Objectives: To evaluate the effects of replacing (with resin composite) versus repair (with resin composite) in the management of defective resin composite dental restorations in permanent molar and premolar teeth., Search Methods: For the identification of studies relevant to this review we searched the Cochrane Oral Health Group's Trials Register (to 24 July 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 6); MEDLINE via OVID (1946 to 24 July 2013); EMBASE via OVID (1980 to 24 July 2013); BIOSIS via Web of Knowledge (1969 to 24 July 2013); Web of Science (1945 to 24 July 2013); and OpenGrey (to 24 July 2013). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases., Selection Criteria: Trials were selected if they met the following criteria: randomised controlled trial (including split-mouth studies), involving replacement and repair of resin composite restorations in adults with a defective molar restoration in a permanent molar or premolar teeth., Data Collection and Analysis: Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis., Main Results: The search strategy retrieved 298 potentially eligible studies, after de-duplication. After examination of the titles and abstracts, full texts of potentially relevant studies were retrieved but none of the retrieved studies met the inclusion criteria of the review., Authors' Conclusions: There are no published randomised controlled trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, anxiety and distress, time and costs.

Background: Amalgam is a common filling material for posterior teeth, as with any restoration amalgams have a finite life-span. Traditionally replacement was the ideal approach to treat defective amalgam restorations, however, repair offers an alternative more conservative approach where restorations are only partially defective. Repairing a restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement. Repair of amalgam restorations is often more conservative of the tooth structure than replacement., Objectives: To evaluate the effects of replacing (with amalgam) versus repair (with amalgam) in the management of defective amalgam dental restorations in permanent molar and premolar teeth., Search Methods: For the identification of studies relevant to this review we searched the Cochrane Oral Health Group's Trials Register (to 5 August 2013); the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 7); MEDLINE via OVID (1946 to 5 August 2013); EMBASE via OVID (1980 to 5 August 2013); BIOSIS via Web of Knowledge (1969 to 5 August 2013); Web of Science (1945 to 5 August 2013) and OpenGrey (to 5 August 2013). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. No restrictions were placed on the language or date of publication when searching the electronic databases., Selection Criteria: Trials were selected if they met the following criteria: randomised controlled trial (including split-mouth studies), involving replacement and repair of amalgam restorations in adults with a defective restoration in a molar or premolar tooth/teeth., Data Collection and Analysis: Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis., Main Results: The search strategy retrieved 201 potentially eligible studies after de-duplication. After examination of the titles and abstracts, full texts of the relevant studies were retrieved but none of these met the inclusion criteria of the review., Authors' Conclusions: There are no published randomised controlled trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, distress and anxiety, time and costs.

Background/aims: To test whether mechanical hyperalgesia is associated with multiple idiopathic pain disorders (IPDs) and whether this relationship is independent of the confounding effects of psychosocial factors., Methods: One hundred eighteen subjects with chronic orofacial pain (COFP) were identified from their questionnaire responses to a population study in North West England. All subjects had a tender point examination according to the American College of Rheumatology classification. Validated tools on the questionnaire were used to identify presence of other IPDs (irritable bowel syndrome and chronic widespread pain) and psychosocial factors (anxiety, depression, health anxiety, sleep disturbance and reporting of somatic symptoms and adverse life events)., Results: Of the 118 subjects, 47.6% (n = 56) had COFP, 34.7% (n = 41) had COFP plus one IPD and 17.8% (n = 21) had all three IPDs. Univariate analysis revealed a dose-response relationship between number of tender points (TPs) and number of IPDs [2-6 TPs (OR 2.6, 95% CI 1.0-7.3), ≥ 7 TPs (OR 10.5, 95% CI 3.8-29.3)] and number of IPDs and psychological distress [anxiety (OR 2.8, 95% CI 1.2-6.4), depression (OR 4.3, 95% CI 1.7-10.6), sleep disturbance (OR 4.8, 95% CI 1.6-14.6)]. The relationship between IPDs and TPs persisted after adjusting for psychosocial factors in multivariate analyses [2-6 TPs (OR 2.5, 95% CI 0.8-7.8) ≥ 7 TPs (OR 10.7, 95% CI 3.4-33.7)]., Conclusion: The dose-response relationship between TPs and IPDs needs further investigation to determine the temporal nature of these relationships and to disentangle the complex gene-environment relationships that may influence the occurrence of multiple IPDs., (© 2012 European Federation of International Association for the Study of Pain Chapters.)

Background: Psychosocial factors have a role in the onset of chronic orofacial pain. However, current management involves invasive therapies like occlusal adjustments and splints which lack an evidence base., Objectives: To determine the efficacy of non-pharmacologic psychosocial interventions for chronic orofacial pain., Search Methods: The following electronic databases were searched: the Cochrane Oral Health Group Trials Register (to 25 October 2010), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 4), MEDLINE via OVID (1950 to 25 October 2010), EMBASE via OVID (1980 to 25 October 2010) and PsycINFO via OVID (1950 to 25 October 2010). There were no restrictions regarding language or date of publication., Selection Criteria: Randomised controlled trials which included non-pharmacological psychosocial interventions for adults with chronic orofacial pain compared with any other form of treatment (e.g. usual care like intraoral splints, pharmacological treatment and/or physiotherapy)., Data Collection and Analysis: Data were independently extracted in duplicate. Trial authors were contacted for details of randomisation and loss to follow-up, and also to provide means and standard deviations for outcome measures where these were not available. Risk of bias was assessed and disagreements between review authors were discussed and another review author involved where necessary., Main Results: Seventeen trials were eligible for inclusion into the review. Psychosocial interventions improved long-term pain intensity (standardised mean difference (SMD) -0.34, 95% confidence interval (CI) -0.50 to -0.18) and depression (SMD -0.35, 95% CI -0.54 to -0.16). However, the risk of bias was high for almost all studies. A subgroup analysis revealed that cognitive behavioural therapy (CBT) either alone or in combination with biofeedback improved long-term pain intensity, activity interference and depression. However the studies pooled had high risk of bias and were few in number. The pooled trials were all related to temporomandibular disorder (TMD)., Authors' Conclusions: There is weak evidence to support the use of psychosocial interventions for chronic orofacial pain. Although significant effects were observed for outcome measures where pooling was possible, the studies were few in number and had high risk of bias. However, given the non-invasive nature of such interventions they should be used in preference to other invasive and irreversible treatments which also have limited or no efficacy. Further high quality trials are needed to explore the effects of psychosocial interventions on chronic orofacial pain.

Background: Composite filling materials have been increasingly used for the restoration of posterior teeth in recent years as a tooth coloured alternative to amalgam. As with any filling material composites have a finite life-span. Traditionally, replacement was the ideal approach to treat defective composite restorations, however, repairing composites offers an alternative more conservative approach where restorations are partly still serviceable. Repairing the restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement., Objectives: To evaluate the effectiveness of replacement (with resin composite) versus repair (with resin composite) in the management of defective resin composite dental restorations in permanent molar and premolar teeth., Search Strategy: For the identification of studies relevant to this review we searched the Cochrane Oral Health Group Trials Register (to 23rd September 2009); CENTRAL (The Cochrane Library 2009, Issue 4); MEDLINE (1950 to 23rd September 2009); EMBASE (1980 to 23rd September 2009); ISI Web of Science (SCIE, SSCI) (1981 to 22nd December 2009); ISI Web of Science Conference Proceedings (1990 to 22nd December 2009); BIOSIS (1985 to 22nd December 2009); and OpenSIGLE (1980 to 2005). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. There were no language limitations., Selection Criteria: Trials were selected if they met the following criteria: randomised or quasi-randomised controlled trial, involving replacement and repair of resin composite restorations., Data Collection and Analysis: Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis., Main Results: The search strategy retrieved 279 potentially eligible studies, after de-duplication and examination of the titles and abstracts all but four studies were deemed irrelevant. After further analysis of the full texts of the four studies identified, none of the retrieved studies met the inclusion criteria and all were excluded from this review., Authors' Conclusions: There are no published randomised controlled clinical trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled clinical trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, anxiety and distress, time and costs.

Background: Amalgam is a common filling material for posterior teeth, as with any restoration amalgams have a finite life-span. Traditionally replacement was the ideal approach to treat defective amalgam restorations, however, repair offers an alternative more conservative approach where restorations are only partially defective. Repairing a restoration has the potential of taking less time and may sometimes be performed without the use of local anaesthesia hence it may be less distressing for a patient when compared with replacement., Objectives: To evaluate the effectiveness of replacement (with amalgam) versus repair (with amalgam) in the management of defective amalgam dental restorations in permanent molar and premolar teeth., Search Strategy: For the identification of studies relevant to this review we searched the Cochrane Oral Health Group Trials Register (to 23rd September 2009); CENTRAL (The Cochrane Library 2009, Issue 4); MEDLINE (1950 to 23rd September 2009); EMBASE (1980 to 23rd September 2009); ISI Web of Science (SCIE, SSCI) (1981 to 22nd December 2009); ISI Web of Science Conference Proceedings (1990 to 22nd December 2009); BIOSIS (1985 to 22nd December 2009); and OpenSIGLE (1980 to 2005). Researchers, experts and organisations known to be involved in this field were contacted in order to trace unpublished or ongoing studies. There were no language limitations., Selection Criteria: Trials were selected if they met the following criteria: randomised or quasi-randomised controlled trial, involving replacement and repair of amalgam restorations., Data Collection and Analysis: Two review authors independently assessed titles and abstracts for each article identified by the searches in order to decide whether the article was likely to be relevant. Full papers were obtained for relevant articles and both review authors studied these. The Cochrane Collaboration statistical guidelines were to be followed for data synthesis., Main Results: The search strategy retrieved 145 potentially eligible studies, after de-duplication and examination of the titles and abstracts all but three studies were deemed irrelevant. After further analysis of the full texts of the three studies identified, none of the retrieved studies met the inclusion criteria and all were excluded from this review., Authors' Conclusions: There are no published randomised controlled clinical trials relevant to this review question. There is therefore a need for methodologically sound randomised controlled clinical trials that are reported according to the Consolidated Standards of Reporting Trials (CONSORT) statement (www.consort-statement.org/). Further research also needs to explore qualitatively the views of patients on repairing versus replacement and investigate themes around pain, distress and anxiety, time and costs.

Objectives: (i) To examine the association between self-reported mechanical factors and chronic oro-facial pain. (ii) To test the hypothesis that this relationship could be explained by: (a) reporting of psychological factors, (b) common association of self-reported mechanical factors with other unexplained syndromes., Methods: A population based cross-sectional study of 4200 randomly selected adults registered with a General Medical Practice in North West, England. The study examined the association of chronic oro-facial pain with a variety of self-reported mechanical factors: teeth grinding, facial trauma, missing teeth and the feeling that the teeth did not fit together properly. Information was also collected on demographic factors, psychological factors and the reporting of other frequently unexplained syndromes., Results: An adjusted response rate of 72% was achieved. Only two mechanical factors: teeth grinding (odds ratio (OR) 2.0, 95% CI 1.3-3.0) and facial trauma (OR 2.0; 95% CI 1.3-2.9) were independently associated with chronic oro-facial pain after adjusting for psychological factors. However, these factors were also commonly associated with the reporting of other frequently unexplained syndromes: teeth grinding (odds ratio (OR) 1.8, 95% CI 1.5-2.2), facial trauma (OR 2.1; 95% CI 1.7-2.6)., Conclusions: Self-reported mechanical factors associated with chronic oro-facial pain are confounded, in part, by psychological factors and are equally common across other frequently unexplained syndromes. They may represent another feature of somatisation. Therefore the use of extensive invasive therapy such as occlusal adjustments and surgery to change mechanical factors may not be justified in many cases.