Classifying orofacial pains: a new proposal of taxonomy based on ontology.

We propose a new taxonomy model based on ontological principles for disorders that manifest themselves through the symptom of persistent orofacial pain and are commonly seen in clinical practice and difficult to manage. Consensus meeting of eight experts from various geographic areas representing different perspectives (orofacial pain, headache, oral medicine and ontology) as an initial step towards improving the taxonomy. Ontological principles were introduced, reviewed and applied during the consensus building process. Diagnostic criteria for persistent dento-alveolar pain disorder (PDAP) were formulated as an example to be used to model the taxonomical structure of all orofacial pain conditions. These criteria have the advantage of being (i) anatomically defined, (ii) in accordance with other classification systems for the provision of clinical care, (iii) descriptive and succinct, (iv) easy to adapt for applications in varying settings, (v) scalable and (vi) transferable for the description of pain disorders in other orofacial regions of interest. Limitations are that the criteria introduce new terminology, do not have widespread acceptance and have yet to be tested. These results were presented to the greater conference membership and were unanimously accepted. Consensus for the diagnostic criteria of PDAP was established within this working group. This is an initial first step towards developing a coherent taxonomy for orofacial pain disorders, which is needed to improve clinical research and care.

Age and third molar extraction as risk factors for temporomandibular disorder.

This study investigated third molar removal as a risk factor for temporomandibular disorder (TMD) in all age groups. We compared 2217 Kaiser Permanente Northwest health plan enrollees with a history of third molar extraction with 2217 age-and gender-matched enrollees with radiographic confirmation of no lifetime third molar removal. Common Dental Terminology codes were used to identify information on third molar removal, and International Classification of Disease codes were used to identify TMD. Relative risks were calculated overall, and by each decade of life, in univariate and multivariate analyses. The incidence of TMD in subjects with and without third molar removal were 7 and 5 per thousand person-years, respectively. Third molar removal among subjects of all ages resulted in a statistically insignificant increased relative risk for TMD (1.4, 95% confidence interval (CI): 0.9-2.2). The relative risk was slightly higher in those under 21, but was also not statistically significant (1.6, CI: 0.8-3.1).

Risk factors for diagnostic subgroups of painful temporomandibular disorders (TMD).

Temporomandibular Disorders (TMD) encompass several entities, which may have differing etiologies. To test this hypothesis, we investigated risk factors for three diagnostic subgroups of painful TMD. Ninety-seven subjects with myofascial pain only, 20 with arthralgia only, 157 with both myofascial pain and arthralgia, and 195 controls without TMD pain met criteria for study eligibility. Investigated risk factors included both physical and psychological variables. Adjusted odds ratios were calculated by multiple logistic regression analyses. Myofascial pain occurring alone was significantly associated with trauma (Odds Ratio [OR] = 2.0), clenching (OR = 4.8), third molar removal (OR = 3.2), somatization (OR = 3.7), and female gender (OR = 4.2). Myofascial pain with arthralgia was significantly associated with trauma (OR = 2.1), clenching (OR = 3.3), third molar removal (OR = 4.0), somatization (OR = 5.1), and female gender (OR = 4.7). No significant associations were found for the small-arthralgia-only group.

Overbite and overjet are not related to self-report of temporomandibular disorder symptoms.

Overbite and overjet, especially high or low values, have been found in some studies to be associated with temporomandibular disorders (TMD). This study evaluates the relationship between overbite/overjet and three TMD self-report measures (pain, joint noises, limited mouth-opening). Subjects were from two population-based cross-sectional studies (3033 subjects). After adjustment for age and gender, high or low values of overbite were not associated with an increased risk of self-reported TMD pain as compared with a reference category of a normal overbite of 2 to 3 mm (-8 to -1 mm, odds ratio = 0.36, 95% confidence interval = 0.05-2.76; 6 to 15 mm, odds ratio = 1.08, 95% confidence interval = 0.68-1.72). Similar non-significant results were found for overjet and TMD pain, and for the association of overjet/overbite and joint noises or limited mouth-opening. This study provides the strongest evidence to date that there is no association between overbite or overjet and self-reported TMD.

A new causal model of dental diseases associated with endocarditis.

Infective endocarditis (IE) is a serious disease that is associated with dental diseases and treatment. The objective of this study was to summarize the epidemiological information about IE and reevaluate previous causal models in light of this evidence. The world biomedical literature was searched from 1930 to 1996 for descriptive and analytic epidemiological studies of IE. Multiple searching strategies were performed on 9 databases, including MEDLINE, CATLINE, and WORLDCAT. Results show that: 1) the incidence of IE varies between 0.70 to 6.8 per 100,000 person-years: 2) the incidence of IE increases 20 fold with advancing age: 3) over 50% of all IE cases are not associated with either an obvious procedural or infectious event 3 months prior to developing symptoms; 4) about 8% of all IE cases are associated with periodontal or dental disease without a dental procedure: 5) the time from the diagnosis of heart valve deformities to the development of IE approaches 20 years: 6) the median time from identifiable procedures to the onset of IE symptoms is about 2 to 4 weeks: 7) the risk of IE after a dental procedure is probably in the range of 1 per 3,000 to 5,000 procedures: and 8) over 80% of all IE cases are acquired in the community, and the bacteria are part of the host's endogenous flora. The synthesis of these data demonstrates that IE is a disorder with the epidemiological picture of a chronic disease such as cancer, instead of an acute infectious disease, with a long latent period and possibly several definable intermediates or stages. A new causal model is proposed that includes early bacteremias that may "prime" the endothelial surface of the heart valves over many years, and a late bacteremia over days to weeks that allows adherence and colonization of the valve, resulting in the characteristic fulminant infection.

Epidemiology of intracranial meningioma.

Intracranial meningiomas arise from the meninges and typically have benign histologic findings. They constitute approximately 20% of all intracranial tumors. Their incidence increases with age, and they affect women more commonly than men. The annual incidence per 100,000 people ranges from two to seven for women and from one to five for men. Since the first study was published in 1970, only eight major epidemiologic studies have been done that attempted to identify risk factors for meningioma. Ionizing radiation and head trauma have emerged as the most promising etiologic risk factors. In these studies, radiation doses as low as 1-2 Gy have been associated with increased risk. The role of dental radiographs has been suggested in some studies but not supported in others. An explanation for the apparent excess of meningiomas in women remains obscure. The potential effects of endogenous or exogenous sex hormones on tumor induction or growth remain unexplored in epidemiologic studies. More should be learned about the risk factors for meningioma in search of opportunities for prevention.

Microcomputer analysis of cortical power spectrum: calibration and correlates of behavioral artifacts.

Cortical power spectrum (CPS) is a quantitative estimate of EEG spectral power density. The CPS provides suitably precise data for quantification and statistical inference compared to the qualitative evaluation of EGG when interpreted by clinicians or researchers. In the past decade, the CPS has been applied to the studies of cognitive functions, memory, psi phenomena, speech laterality, and states of consciousness including coma, sleep, anesthesia, pathophysiology and pain state. However, few systematic evaluations of CPS methodology have been reported, rendering cross-laboratory comparisons difficult and external validity of experimental results uncertain. This report first describes a calibration procedure employing a microcomputer system for measuring the functional relationship between input signals and output cortical powers. Second, we examine controlled behavioral artifact effects on the CPS. The behavioral artifacts observed in the CPS can provide a measurement anchor for less ambiguous interpretation of CPS experiments conducted in clinical or laboratory settings.

Cortical power spectral analysis of acute pathophysiological pain.

In the past decade, advances in quantitative EEG methods, such as the analysis of cortical power spectrum, have proven a useful tool for observing changes in brain activity as a function of physiological and behavioral states. The cortical power spectrum (CPS) is a computer-derived analysis of brain electrical activity using mathematical principles of Fast Fourier Transform function. The total energy output of specific cortical areas can be estimated over time, as a function of EEG spectral frequencies. This report describes the study of CPS in pathophysiological pain patients, using acute dental pain as a model. Seven "walk-in" acute pain patients in an emergency dental clinic were recorded during 10 min of pain, before treatment. Approximately one week later, 10 min recordings during nonpain states were obtained as control. Subjective pain scales and other psychological measures were administered to all subjects before and after recording on each visit. Each 10 min stage of continuous CPS recording consisted of 10 spectra per stage, 6 epochs/spectrum, and 10.24 sec/epoch; each spectrum was stored, averaged, transformed, displayed, printed, and plotted by the Pain Microcomputer System. Results show significant cortical power reduction along all frequency bands (0.5-50 Hz) when pain-states are compared to nonpain states. The magnitude of reduction also appears to correspond to subjective pain report. Analysis for rank order may be inversely related to subjective painfulness, indicating that pain and alpha-desynchronization are closely associated. This study demonstrates that the brain activity of clinical pain patients can be measured. The feasibility of developing a pathophysiological objective pain measuring system is discussed.