Chronic orofacial pain.

While pain chronicity in general has been defined as pain lasting for more than 3 months, this definition is not useful in orofacial pain (OFP) and headache (HA). Instead, chronicity in OFP and HA is defined as pain occurring on more than 15 days per month and lasting for more than 4 h daily for at least the last 3 months. This definition excludes the periodic shortlasting pains that often recur in the face and head, but are not essentially chronic. Although the headache field has adopted this definition, chronic orofacial pain is still poorly defined. In this article, we discuss current thinking of chronicity in pain and examine the term 'chronic orofacial pain' (COFP). We discuss the entities that make up COFP and analyze the term's usefulness in clinical practice and epidemiology.

Oro-facial pain and temporomandibular disorders classification systems: A critical appraisal and future directions.

It is a difficult undertaking to design a classification system for any disease entity, let alone for oro-facial pain (OFP) and more specifically for temporomandibular disorders (TMD). A further complication of this task is that both physical and psychosocial variables must be included. To augment this process, a two-step systematic review, adhering to PRISMA guidelines, of the classification systems published during the last 20 years for OFP and TMD was performed. The first search step identified 190 potential citations which ultimately resulted in only 17 articles being included for in-depth analysis and review. The second step resulted in only 5 articles being selected for inclusion in this review. Five additional articles and four classification guidelines/criteria were also included due to expansion of the search criteria. Thus, in total, 14 documents comprising articles and guidelines/criteria (8 proposals of classification systems for OFP; 6 for TMD) were selected for inclusion in the systematic review. For each, a discussion as to their advantages, strengths and limitations was provided. Suggestions regarding the future direction for improving the classification process with the use of ontological principles rather than taxonomy are discussed. Furthermore, the potential for expanding the scope of axes included in existing classification systems, to include genetic, epigenetic and neurobiological variables, is explored. It is therefore recommended that future classification system proposals be based on combined approaches aiming to provide archetypal treatment-oriented classifications.

Classification: The key to understanding facial pain.

It is indisputable that the global scientific advances in headache research, be it bench or bedside, have benefited enormously from the operational diagnostic criteria published in 1988. Today, this classification system is indispensable. The reason for this success is a low inter-rater variability. In general, orofacial pain conditions are less well characterised - with the noticeable exemption of temporomandibular disorder pain. Tremendous work has been put into changing this, and significant progress has been achieved - in particular, in terms of the clinical implications and overriding conceptual models for oro-facial pain. Scientific classifications have only one goal: To provide a scientific agreement about the main features of an object of research and a scientific consensus regarding the name. The main significance is not the fact that a good classification offers a detailed and accurate image of the reality. If we want to overcome the obstacles of different competing classification systems, we need to overcome specialisation borders. The key to success is to understand that such a definition does not mirror all possible clinical facets of a given pain condition but is simply a convention - that is, a consensus on a word used for a pain condition. Simply speaking, a classification creates a common language to be used by more than one profession. It will be crucial to define any given pain condition as precisely and rigid as possible, in order to ensure a homogenous population. Only this ensures a low inter-rater variability, which consequently allows combining and comparing research on a population across different professional settings. This is not easy for chronic facial pain without verifiable morphological cause or structural lesions, as these syndromes are often rather featureless. The new IASP classification of chronic pain is a big step forward to a better characterisation of such conditions, and will trigger future work on a new and operationalised classification of oro-facial pain.

Assessment of risk factors for oro-facial pain and recent developments in classification: implications for management.

Oro-facial pain research has during the last decades provided important novel insights into the basic underlying mechanisms, the need for standardised diagnostic procedures and classification systems, and multiple treatment options for successful rehabilitation of the patient in pain. Notwithstanding the significant progress in our knowledge spanning from molecules to chair, there may also be limitations in our ability to integrate and interpret the tremendous amount of new data and information, in particular in terms of the clinical implications and overriding conceptual models for oro-facial pain. The aim of the present narrative review is to briefly summarise some of the current thoughts on oro-facial pain mechanisms and recent attempts to identify biomarkers and risk factors leading to the proposal of a new risk assessment diagram for oro-facial pain (RADOP) and a provocative new concept based on stochastic variation between multiple risk factors. Finally, the implications for novel management strategies will briefly be discussed.

[Orofacial pain - Trigeminal neuralgia and posttraumatic trigeminal neuropathy: Common features and differences]. / Orofazialer Schmerz - Trigeminusneuralgie und posttraumatische Trigeminusneuropathie : Gemeinsamkeiten und Unterschiede.

Neuropathic pain is the result of a lesion or disease of the somatosensory system in the peripheral or central nervous system. Classical trigeminal neuralgia and posttraumatic trigeminal neuropathy are pain disorders which oral and maxillofacial surgeons and dentists are confronted with in the differential diagnostics in routine daily practice. The etiopathogenesis of classical trigeminal neuralgia is attributable to pathological blood vessel-nerve contact in the trigeminal nerve root entry zone to the brain stem. The typical pain symptoms are characterized by sudden stabbing pain attacks. The pharmaceutical prophylaxis is based on the individually titrated administration of anticonvulsant drugs. The indications for interventional treatment are dependent on the course, response to drug treatment, resilience and wishes of the patient. The neuropathic mechanism of posttraumatic trigeminal neuropathy originates from nerve damage, which leads to peripheral and central sensitization with lowering of the pain threshold and multiple somatosensory disorders. The prophylaxis consists of avoidance of excessive acute and long-lasting pain stimuli. Against the background of the biopsychosocial pain model, the treatment of posttraumatic trigeminal neuropathy necessitates a multimodal, interdisciplinary concept.

Prevalence of the different Axis I clinical subtypes in a sample of patients with orofacial pain and temporomandibular disorders in the Andalusian Healthcare Service.

BACKGROUND: The main objective of this paper is to analyze the prevalence of each of the different clinical subtypes of temporomandibular disorders (TMD) in a sample of patients with this pathology. In addition, a second objective was to analyze their distribution according to gender. MATERIAL AND METHODS: To this end, the results of 1603 patients who went to the Unit of Temporomandibular Disorders in the Córdoba Healthcare District because they suffered from this pathology were analyzed. In order to diagnose them, the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were applied, analyzing the different Axis I subtypes (myopathy, discopathy and arthropathy) and obtaining the combined Axis I for each patient and the relation of all these variables according to gender. The null-hypothesis test confirmed the lack of connection between the gender variable and the different subtypes in the clinical analysis, and between the former and the combined Axis I of the RDC/TMD. RESULTS: The prevalence was high for the muscle disorders subtype in general, showing an 88.7% prevalence, while the presence of discopathies or arthropathies was much lower. Among discopathies, the most frequent ones were disc displacements with reduction, with 39.7% and 42.8% for the left and right temporomandibular joints (TMJ), respectively, while the prevalence of arthropathies was 26.3% for the right TMJ and 32.9% for the left TMJ. The bivariate analysis on the connection with gender reveals a p≥ 0.05 value for the muscle and arthralgia subtypes. CONCLUSIONS: The patients seen at the TMD Unit where mostly middle-aged women whose main clinical axis subtype was the muscle disorder subtype. For their part, both discopathies and arthropathies, although present, are much less prevalent.

[Classification of pain in the orofacial and craniofacial regions]. / Classificatie van pijn in het orofaciale en craniofaciale gebied.

Pain is a multidimensional, subjective phenomenon that can only be understood within the context of an individual operating in a specific environment. As a consequence, it is difficult from an objective standpoint to satisfy the established criteria for classification. In general, it is the case that available classification systems can only partially capture pain in all of its complexity. There are various general and specific classification systems. In 2017, the International Classification of Diseases will be complemented with classification possibilities related to chronic pain. Recently, a committee established by the Dutch Pain Society has formulated a proposal for the development of a definition and classification system for chronic pain to be applied in the Netherlands.

[Measuring orofacial pain]. / Pijnmeting bij orofaciale pijn.

Pain is a complex neuro-physiological phenomenon affecting mind and behaviour, and is in turn also affected by psyche and behaviour. Differences among individuals in modulation, interpretation and expression complicate the comparison of pain between patients. Pain is a subjective experience and can be expressed by the patient in many different ways. In addition, influential factors from a bio-psycho-social perspective have to be taken into consideration: the interaction among somatic, psychological and social factors determines the ultimate pain experience and pain behaviour. Measuring pain therefor requires a multi-dimensional approach in which the pain, observed from various levels, and the associated problems can be determined.

Perspectives on next steps in classification of oro-facial pain - part 1: role of ontology.

The purpose of this study was to review existing principles of oro-facial pain classifications and to specify design recommendations for a new system that would reflect recent insights in biomedical classification systems, terminologies and ontologies. The study was initiated by a symposium organised by the International RDC/TMD Consortium Network in March 2013, to which the present authors contributed. The following areas are addressed: problems with current classification approaches, status of the ontological basis of pain disorders, insufficient diagnostic aids and biomarkers for pain disorders, exploratory nature of current pain terminology and classification systems, and problems with prevailing classification methods from an ontological perspective. Four recommendations for addressing these problems are as follows: (i) develop a hypothesis-driven classification structure built on principles that ensure to our best understanding an accurate description of the relations among all entities involved in oro-facial pain disorders; (ii) take into account the physiology and phenomenology of oro-facial pain disorders to adequately represent both domains including psychosocial entities in a classification system; (iii) plan at the beginning for field-testing at strategic development stages; and (iv) consider how the classification system will be implemented. Implications in relation to the specific domains of psychosocial factors and biomarkers for inclusion into an oro-facial pain classification system are described in two separate papers.

Perspectives on next steps in classification of oro-facial pain - part 2: role of psychosocial factors.

This study was initiated by a symposium, in which the present authors contributed, organised by the International RDC/TMD Consortium Network in March 2013. The purpose of the study was to review the status of biobehavioural research - both quantitative and qualitative - related to oro-facial pain (OFP) with respect to the aetiology, pathophysiology, diagnosis and management of OFP conditions, and how this information can optimally be used for developing a structured OFP classification system for research. In particular, we address representation of psychosocial entities in classification systems, use of qualitative research to identify and understand the full scope of psychosocial entities and their interaction, and the usage of classification system for guiding treatment. We then provide recommendations for addressing these problems, including how ontological principles can inform this process.

Perspectives on next steps in classification of oro-facial pain - Part 3: biomarkers of chronic oro-facial pain - from research to clinic.

The purpose of this study was to review the current status of biomarkers used in oro-facial pain conditions. Specifically, we critically appraise their relative strengths and weaknesses for assessing mechanisms associated with the oro-facial pain conditions and interpret that information in the light of their current value for use in diagnosis. In the third section, we explore biomarkers through the perspective of ontological realism. We discuss ontological problems of biomarkers as currently widely conceptualised and implemented. This leads to recommendations for research practice aimed to a better understanding of the potential contribution that biomarkers might make to oro-facial pain diagnosis and thereby fulfil our goal for an expanded multidimensional framework for oro-facial pain conditions that would include a third axis.

Pain Part 5a: Chronic (Neuropathic) Orofacial Pain.

Neuropathic pain is a significant social and economic burden. Back pain, joint pain and headaches affect over 30% of the population. Chronic orofacial pain is a common condition and is difficult to diagnose and manage. This two-part paper aims to provide an overview of novel understanding of neuropathic pain, and furnish clinical teams with an update on the less common and less well-recognized chronic orofacial conditions. Headaches and temporomandibular disorders are the most common conditions and are covered in separate papers (6 and 10). Trigeminal neuralgia, burning mouth, and trigeminal autonomic cephalgias are also covered in separate papers (7, 8 and 9). The remaining conditions: post-traumatic neuropathy (nerve injury); and persistent idiopathic facial pain and atypical odontalgia are discussed in this and the following paper. Clinical Relevance: Neuropathic pain, though rare, is a consequence of dental treatment. Nerve injury in relation to M3M surgery, dental implants, endodontics and local anaesthesia result in 70% of affected patients experiencing chronic neuropathic pain.

Pain paper 2b: classification of orofacial pain and an update on assessment and diagnosis.

The classification of chronic orofacial pain remains a contentious area. However, more recently, with the clarification of pain mechanisms and improved understanding of the underlying neurophysiology and modulation factors, there is more clarity of the possible division of pain conditions. Interestingly, the pathophysiology provides a basis for classification that has more clinical relevance. The principles of assessing and managing patients with pain have modified significantly, in line with recent improved understanding of the affective and emotional components in pain behaviour and suffering. Clinical Relevance: This paper aims to provide the dental and medical teams with a review of the classification of trigeminal pain with an overview of how to assess and diagnose patients with trigeminal pain.

Persistent dentoalveolar pain: the patient's experience.

AIMS: To build an understanding of the patient's experience and from this identify recurring themes that could form part of an item pool for further testing of persistent dentoalveolar pain disorder (PDAP). METHODS: Proven cases of PDAP were identified from a clinical database, and a purposive maximum variation sample was drawn. Semi-structured interviews were conducted with the sample by a single trained interviewer. Interviews were digitally recorded and transcribed verbatim. Data collection and analysis occurred until data saturation (n = 20), with no new themes emerging. Analysis of the data was an iterative and inductive process broadly following the principles of the constant comparative method. RESULTS: Recurrent themes emerging from the data were: difficulty in responding to history taking; duration and magnitude of pain; complex and confounding descriptors; common exacerbating factor; well-localized pain; deep pain; pressurized or pressure feeling. CONCLUSION: Several common experiences that can be considered items were identified in the data. These items will add to the limited pre-existing item pool in the literature and allow testing of this item pool to determine those items best suited to form an adjunctive self-report diagnostic instrument for PDAP.

Research Diagnostic Criteria Axis II in screening and as a part of biopsychosocial subtyping of Finnish patients with temporomandibular disorder pain.

AIMS: To assess Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) Axis II variables in an initial psychosocial screening and as a part of biopsychosocial subtyping of Finnish referral patients with TMD pain for adjunct multidisciplinary assessment. METHODS: Consecutive Finnish referral patients with TMD pain (n = 135) participated in this questionnaire-based survey. Psychosocial screening was based on Graded Chronic Pain Scale (GCPS) and culturally adjusted Symptom Checklist 90-revised (SCL-90R) depression scale scores and subtyping on GCPS pain-related interference in accordance with previous treatment tailoring studies. Biopsychosocial subtyping variables included symptoms of depression and somatization, general health, pain-related worry, sleep dysfunction, and coping ability. Subtype comparisons were analyzed with Bonferroni adjusted P values and multivariable logistic regression (SAS 9.3). RESULTS: Based on psychosocial screening, 44% of the patients were psychosocially uncompromised (TMD subtype 1), 33% moderately, and 23% severely compromised (TMD subtypes 2 and 3). Compared to TMD subtype 1, TMD subtype 2 patients reported intermediate scores, and the most vulnerable TMD subtype 3 had the poorest general health, most elevated depression, somatization, worry and sleep dysfunction, and poor coping ability (P < .05). According to multivariable logistic regression, depression and worry levels were significantly higher in TMD subtype 3 compared to TMD subtype 1, whilst patients in TMD subtypes 1 and 2 reported significantly better coping ability compared to TMD subtype 3 (P < .05). CONCLUSION: The Finnish RDC/TMD Axis II was found reliable in initial TMD pain patient screening and with further biopsychosocial assessment identified three main TMD subtypes, two with compromised psychosocial profiles for adjunct multidisciplinary assessment.

Ranking of dental and somatic pain sensations among paediatric dental patients.

BACKGROUND: Children suffer from somatic and dental pain, which may interfere with their everyday life. Pain self-report tools are available for children. Research is needed to better understand the perception of dental pain in comparison with pain in other organs. AIM: To investigate relations between the perceptions of dental and somatic pain complaints among school-age children. DESIGN: One hundred and two children, aged 7-17 years (mean age, 11.5 ± 2.65 years), completed questioners regarding their somatic and dental: 1. Memory pain rank (MPR) and 2. Wong-Baker FACES Pain Rating Scale (FRS). RESULTS: Children reported increased dental pain after school in both scales (P = 0.015 in MPR). In both MPR and FRS, the pattern of pain ranking was similar: Abdominal pain was scored highest (2.75 ± 1.4 and 1.56 ± 1.63, respectively), followed by headache, ear, dental and TMJ (Temporomandibular joint). CONCLUSION: There was a strong correlation between pain perception and current pain scores in every organ. Somatic pain, namely head, abdomen and ears, was ranked significantly higher than dental and TMJ pain. School-aged children rank current pain and pain experience significantly lower while they are pre-occupied (school time) in comparison with times when they are less busy (after school time).

Diagnostic criteria for headache attributed to temporomandibular disorders.

AIMS: We assessed and compared the diagnostic accuracy of two sets of diagnostic criteria for headache secondary to temporomandibular disorders (TMD). METHODS: In 373 headache subjects with TMD, a TMD headache reference standard was defined as: self-reported temple headache, consensus diagnosis of painful TMD and replication of the temple headache using TMD-based provocation tests. Revised diagnostic criteria for Headache attributed to TMD were selected using the RPART (recursive partitioning and regression trees) procedure, and refined in half of the data set. Using the remaining half of the data, the diagnostic accuracy of the revised criteria was compared to that of the International Headache Society's International Classification of Headache Diseases (ICHD)-II criteria A to C for Headache or facial pain attributed to temporomandibular joint (TMJ) disorder. RESULTS: Relative to the TMD headache reference standard, ICHD-II criteria showed sensitivity of 84% and specificity of 33%. The revised criteria for Headache attributed to TMD had sensitivity of 89% with improved specificity of 87% (p < 0.001). These criteria are (1) temple area headache that is changed with jaw movement, function or parafunction and (2) provocation of that headache by temporalis muscle palpation or jaw movement. CONCLUSION: Having significantly better specificity than the ICHD-II criteria A to C, the revised criteria are recommended to diagnose headache secondary to TMD.

Expression and localization of aquaporin-1 in temporomandibular joint disc with internal derangement.

BACKGROUND: Internal derangement is the most frequent arthropathy affecting the temporomandibular joint, where its commonest form is anterior disc displacement with or without reduction. Despite the frequency of the disorder, the biochemical features of displaced discs are still unclear. METHODS: We investigated the expression pattern and localization of aquaporin-1, an important channel protein involved in plasma membrane water permeability, in patients with anterior disc displacement (both with and without reduction), with a view to assessing the characteristics of local tissue responses to the microenvironmental changes induced by abnormal mechanical loading of the displaced disc. Protein expression was studied by immunohistochemistry in different areas of discs from 18 patients with anterior disc displacement with or without reduction and in four normal controls. RESULTS: A greater proportion of cells immunopositive for aquaporin-1 were detected in diseased than in normal discs. Whereas protein expression was substantially similar in the different areas of normal discs, a significantly larger number of immunopositive cells were detected in the posterior band of displaced discs without reduction and in the anterior and intermediate bands of those with reduction. CONCLUSIONS: These findings suggest that aquaporin-1 is expressed and upregulated in temporomandibular joint with anterior disc displacement (both with and without reduction).