Electromyographic activity of frontalis and sternocleidomastoid muscles in patients with temporomandibular disorders.

Little is known of the effects of an interocclusal appliance on the activity of craniocervical muscles in patients with temporomandibular disorder. The bilateral electromyographic activity of the frontalis muscle and sternocleidomastoid muscle were assessed in 10 patients with temporomandibular disorders and eight gender, age and dentally matched asymptomatic control subjects during rest and different clenching tasks with or without an interocclusal appliance. Clenching significantly increased both frontalis and sternocleidomastoid activity from rest. Clenching with an interocclusal appliance, as compared with clenching alone, also significantly reduced frontalis activity in both groups, but not for sternocleidomastoid. Increased electromyographic activity of these muscles may represent co-activation of the craniocervical musculature during clenching.

Temporomandibular disorder subtypes according to self-reported physical and psychosocial variables in female patients: a re-evaluation.

Several studies support the relevance of psychological and psychosocial factors in the assessment and management of chronic musculoskeletal pain disorders, including temporomandibular pain disorders (TMDs). The aim of this study was to re-evaluate subtyping approach used in an earlier study (TI Suvinen, KR Hanes, JA Gerschman, PC Reade. J Orofac Pain 1997;11:200) and to compare perceived physical symptoms, psychological, coping and psychosocial variables between subtypes of patients who seek treatment for their temporomandibular pain and dysfunction. A total of 41 consecutive female patients were assessed multiaxially for physical symptoms, coping style and effectiveness and illness behaviour by a previously validated Temporomandibular Pain Dysfunction Questionnaire (TI Suvinen, KR Hanes, JA Gerschman, PC Reade. J Orofac Pain 1997;11:200). Additional measures of psychosocial variables included the global scores of the Beck Depression and Anxiety Inventory and Part I of the Multidimensional Pain Inventory. Subtypes were generated using an iterative partitioning method, k-means cluster analysis. Three clusters were identified and termed as Simple (22%), Intermediate (41%) and Complex (37%) temporomandibular disorders subtypes. Significant differences (P < 0.05) were found between clusters in psychological (coping style and effectiveness, disease conviction and affective disturbance) and in psychosocial variables (daily interference and social, work and family satisfaction), but not between physical variables. The results support previous studies that have shown differences in psychosocial variables in the presentation and subtyping of TMDs and the biopsychosocial orientation in assessment. The findings need to be reverified in a larger sample along specific physical diagnoses, but it is tentatively proposed how the three subtypes could be used in the classification of temporomandibular pain patients to guide management, based on the constellation of predominant psychological and psychosocial illness impact variables.

The effect of an interocclusal appliance on bite force and masseter electromyography in asymptomatic subjects and patients with temporomandibular pain and dysfunction.

The aims of this study were to assess the effect of clenching with or without the presence of an interocclusal appliance (IOA) on bite force (BF) and masseter electromyography (EMG) in patients with temporomandibular pain dysfunction disorders (TMPD) and to compare these results with an asymptomatic age- and gender-matched control group. Ten patients with TMPD (mean age 26.9 years) were compared with eight healthy controls (mean age 25.3 years). Bilateral masseter EMG activity was recorded at rest, while clenching on the BF meter, while clenching on an IOA and while clenching on an IOA together with the BF meter. Significant left to right EMG activity asymmetry was found in the patient group at rest and during multiple clenching tasks in the control group. The patient group had significantly greater EMG activity at rest than controls. For all other tasks, the control group EMG activity was greater than the patient group. Use of an IOA significantly decreased EMG activity in both patient and control groups. BF was significantly greater in the control group on the right side for the different clenching tasks. Insertion of the IOA significantly increased BF in the control group. The results of this study indicate differences in EMG activity and BF during different clenching tasks and between patients with TMPD and asymptomatic subjects.

Vertical jaw separation and masseter muscle electromyographic activity: a comparative study between asymptomatic controls & patients with temporomandibular pain & dysfunction.

The aims of the present study were to assess the relationship pattern between bilateral masseter muscle electromyographic (MEMG) activity recordings and vertical jaw separation (VJS). Asymptomatic subjects (n = 15) were compared with age and gender-matched patients (n = 18) with temporomandibular pain and dysfunction (TMPD); before and after undergoing interocclusal appliance (IOA) therapy for 4 months. In asymptomatic subjects a bilateral minimum MEMG activity was found in a 'resting zone' at approximately a quarter of maximum mandibular opening (mean, 15.4 mm of VJS; range, 5.5-22.5 mm including overbite). No overall relationship between MEMG and VJS was shown for patients with TMPD. After successful IOA therapy, the majority of TMPD patients (14 of 18) showed normalization of the relationship between MEMG and VJS, but electromyographic assessment was not found to be of value as a single objective assessment parameter in evaluating the resolution of TMPD or the effectiveness of IOA therapy.

Epithelial-mesenchymal interactions in experimental oral mucosal carcinogenesis.

In an effort to come to a better understanding of human oral mucosal carcinogenesis, an animal model was used in which the carcinogen 4-nitroquinoline-1-oxide was applied to rat palatal mucosa for varying periods of time. Histological and histometric analyses showed that there were quantifiable differences in the palatal epithelium to which carcinogen had been applied in comparison with control tissue. Tissue recombination experiments, using various combinations of the palatal mucosa and analysed after recovery from transplantation to hypothymic BALB/c mice, showed that control epithelium recombined with connective tissue from carcinogen-treated mucosa was altered, indicating that the underlying connective tissue modified histomorphological aspects of the epithelium in the later stages of carcinogenesis.

The effect of interocclusal appliances on temporomandibular joints as assessed by 3D reconstruction of MRI scans.

Magnetic resonance imaging (MRI) enables simultaneous visualization of hard and soft tissues. The aims of the present study were to computer generate three-dimensional (3D) images, reconstructed from MRI scans of normal temporomandibular joints (TMJ), to assess the relative positions of the disc, condyle and articular surface of the temporal bone and to study the effect of two mandibular group function interocclusal appliances (IOAs). Bilateral MRI scans of 2 mm slice thickness were generated for the TMJs of 12 asymptomatic subjects with the image acquisition coils orientated in a corrected oblique sagittal plane. MRI scans were generated for all subjects with 3 mm interincisal distance IOAs, while a subgroup (n = 4) was also scanned with a 5 mm interincisal IOA in situ. An average of 10 slices through each TMJ were generated for the closed mouth and IOA positions. Three-dimensional reconstruction was performed on a 486 IBM compatible computer using a suite of nine programs not commercially available. Three-dimensional images allowed visualization of composite images of joint relationships. Subjective assessment indicated that joint relations in 3D were more informative than multiple separate 2D MRI scans. With the 3 mm IOA in situ, the disc was positioned posteriorly and superiorly to the condyle in three of 12 cases. In four of 12 cases the condyle, and in two of 12 cases both the disc and condyle, were positioned anteriorly and inferiorly. With the 5 mm IOA changes in condyle/disc and condyle/fossa relationships were more variable. It was concluded that 3D images of TMJs enabled the assessment of the positional changes of the condyle/disc and condyle/fossa relationships as altered by IOAs. However, the role of IOAs on the internal arrangements within the TMJ remains variable and is deserving of further study.

p53 expression in oral precancer and cancer.

Expression of the p53 tumour suppressor gene is a frequent finding in human malignancies, including oral cancer, and it has been detected in some potentially malignant lesions. The results of the present project showed that 35 of the 41 (85 per cent) oral mucosal lesions with histological evidence of epithelial dysplasia expressed p53, but the presence or absence of p53 staining could not be used to predict the outcome of potentially malignant oral mucosal lesions.

Ultrastructural changes to the palatal mucosa of rats following the application of 4-nitroquinoline-1-oxide (4NQO) and vitamin C.

Oral mucosal neoplastic disease in rodents has been induced by various chemical carcinogens, including water soluble 4-nitroquinoline-1-oxide (4NQO). It has been suggested that vitamin C can inhibit, delay or prevent the development of neoplasms, as well as enhance the induction of neoplasia. In this investigation, 4NQO was used to produce a high yield of carcinomas of the palatal mucosa of rats in a relatively short period of time and topical vitamin C was applied to delay the neoplastic transformation. The temporal aspects of the ultrastructural changes occurring in 4NQO-induced oral palatal mucosa treated with both 4NQO and vitamin C have been described and discussed.

The role of ascorbic acid in oral cancer and carcinogenesis.

L-ascorbic acid is an essential dietary vitamin in humans, primates and certain mammals and is endogenously synthesised in some species. Epidemiological and ecological studies have shown that L-ascorbic acid has a protective effect against cancer, in particular non-hormone-dependent malignancies, such as oropharyngeal neoplasms. Experimental in vivo and in vitro studies, however, have yielded more controversial results, suggesting that the effects of L-ascorbic acid are dose- and perhaps, time-dependent with different effects depending on the species or organ studied. An update of the epidemiological and experimental evidence linking L-ascorbic acid to oral cancer and carcinogenesis is discussed together with a brief review of the possible mechanisms of action of L-ascorbic acid.

Outcome of therapy in the conservative management of temporomandibular pain dysfunction disorder.

The present study considered predictors of the outcome of treatment for temporomandibular pain dysfunction disorder (TMPD). Thirty-seven patients were assessed with objective and self-report measures of physiological and psychosocial aspects of this disorder at initial assessment and at 6-month follow-up subsequent to conservative physical therapy. Patients were subdivided into slow and rapid responders to conservative physical therapy based on self-reported level of improvement. Measures employed included the Temporomandibular Pain Dysfunction Disorder Questionnaire and the Temporomandibular Pain Dysfunction Disorder Clinical Form. Eighty-one per cent of patients showed a 50% or greater improvement in pain severity at follow-up, with minimal differential changes across the two groups found in the physiological symptoms, while the rapid responding group showed greater improvement in terms of psychosocial factors. These findings indicated that psychosocial factors, particularly coping strategies and illness behaviour, cannot be ignored in the management of TMPD.

Psychophysical subtypes of temporomandibular disorders.

This study presents an approach to the classification of temporomandibular disorders (TMD) based on acknowledgement of the interaction of physical, psychologic, and social factors using a multidimensional instrument that has been previously validated. The psychometric properties of this instrument were reevaluated in 140 women with TMD. Multidimensional clustering identified three subgroups of patients with TMD, including a highly distressed, psychosocially maladaptive group; a moderately distressed, behaviorally functional group; and a predominantly physical disorder group with an unremarkable psychosocial profile. These groups were termed maladaptive, adaptive, and uncomplicated, respectively, according to the constellation of predominant symptoms and psychosocial profiles of each cluster. The groups showed no consistent differences in pain frequency, use of medication, or duration of pain. This finding supports earlier work that suggested the prominence of three subtypes of this disorder according to both physical illness and psychosocial illness impact parameters.

Expression of p53 in oral mucosal hyperplasia, dysplasia and squamous cell carcinoma.

OBJECTIVE: To assess p53 expression in a range of oral mucosal lesions and to relate the results to the clinical outcome in patients with dysplastic oral mucosal lesions and oral squamous cell carcinomas (OSCC). MATERIALS AND METHODS: Archival tissue was available for eight cases of normal oral mucosa, 50 cases of oral mucosal hyperplasia, 41 cases of oral mucosal dysplasia and 48 cases of OSCC. The monoclonal antibody DO-7, reactive to p53 protein, was applied to paraffin-embedded sections using microwave pretreatment and immunohistochemical techniques. RESULTS: The results showed that normal oral mucosa did not express p53. Positive nuclear staining was found in 18/50 (36%) cases of hyperplasia, 35/41 (85%) cases of dysplasia and 45/48 (94%) cases of OSCC. None of the p53 negative dysplasias progressed, while 19% of p53 positive cases of dysplasia recurred following excision and 11% of the cases underwent neoplastic transformation. Five out of 10 (50%) cases of severe dysplasia which were p53 positive resolved. CONCLUSION: The proportion of cases with positive p53 expression increased from hyperplasia to dysplasia to OSCC. These results may indicate an involvement of p53 in neoplastic transformation as well as in proliferative events although the presence or absence of p53 staining could not be used to predict the outcome of potentially malignant oral mucosal lesions.

Temporomandibular disorders: Part II. A comparison of psychologic profiles in Australian and Finnish patients.

Recent recommendations regard musculoskeletal disorders of the masticatory system as dual-axis disorders, but little comparative data of psychologic factors across different pain populations are available. In this study, presenting psychologic profiles were assessed in 40 Australian and 42 Finnish patients diagnosed with temporomandibular disorders. Findings were compared with those of a group of Australian patients reporting acute dental pain and with reference to response to conservative management. The psychologic testing instrument incorporated cognitive, motivational/affective, and illness behavior variables, and it was based on validated general pain questionnaires (Coping Strategies Questionnaire and Illness Behavior Questionnaire). This instrument was found internally reliable in the majority of its subscales in the group studies and provided comparable data to other pain populations. Significant differences in the presenting psychologic profiles were found according to nationality, type of pain suffered, and treatment outcome. Affective disturbance, hypochondriasis, lack of cognitive control, and feeling ill with symptoms were identified in discriminant function analysis as potential predictors of treatment outcome, and they correctly classified 79% of the Australian and 87% of the Finnish patients with temporomandibular disorders. It was concluded that psychologic profiles differed in the two nationalities and were related to treatment outcome. The concept of multiaxial assessment was supported.

Oral squamous cell carcinoma in a young person with candidosis endocrinopathy syndrome: a case report.

Candidosis endocrinopathy syndrome is a rare condition characterized by mucocutaneous candidosis and multiple endocrinal abnormalities. This case reports a patient with the syndrome who also developed an oral mucosal squamous cell carcinoma at the age of 21.

Human immunodeficiency virus infection: a review of the mode of infection, pathogenesis, disease course, and the general and clinical manifestations.

Acquired immunodeficiency syndrome (AIDS) was first recognized in 1981 and in 1983 the virus responsible for this syndrome, the human immunodeficiency virus, was first isolated. There has been an increasing understanding of the many aspects related to infection with this virus and this review discusses the historical as well as the more recent findings related to infection with this virus. In particular, the pathogenesis, mode and course of infection are discussed followed by an overview of the general and oral manifestations of infection with this virus.

Temporomandibular disorders. Part I: A comparison of symptom profiles in Australian and Finnish patients.

Variability in the assessment methods of patients seeking treatment for musculoskeletal disorders of the masticatory system confounds comparative assessment of different studies. In this study, presenting symptom profiles were assessed in 40 Australian and 42 Finnish patients with temporomandibular disorders. The symptom parameters of these patients were compared with those of 40 Australians reporting acute dental pain and were assessed with reference to response to conservative management. A self-administered anamnestic questionnaire was used in a standard, systematic, and comparative way to assess demographic data, general health status, and symptom parameters according to type, frequency, severity, duration, location, impact on the patients' lives, urgency for need of treatment, and possible initiating factors. It was found that the two nationalities studied had similar presentations of cardinal symptom profiles. Statistically significant differences in major presenting symptoms were found between patients with temporomandibular disorders and those with acute dental pain, but not between patients who responded rapidly as opposed to slowly to conservative therapy. It was concluded that the presenting symptom profiles were similar for the two nationalities and were not related to treatment outcome.

Determination of the L-ascorbic acid requirements in Wistar osteogenic disorder Shionogi rats for prolonged carcinogenesis experiments.

Wistar Shionogi rats of the (od/od) substrain with the osteogenic disorder are unable to synthesize L-ascorbic acid (L-AA) and appear to be an appropriate animal model for studying the effect of L-AA in carcinogenesis. To determine the minimal L-AA requirements of these animals for prolonged survival in a satisfactory physical condition during experimentation, four concentrations of L-AA (0.33 g/l, 0.67 g/l, 1.67 g/l and 3.33 g/l) were administered via drinking water to four groups of animals (n = 2). Their water intake per cage was recorded three times weekly and the plasma L-AA levels were determined at the start, after 2, 4, 8 and 12 weeks and at the termination of the experiment. To simulate the procedures to be undertaken in oral mucosal carcinogenesis experiments, the animals were gently restrained and a designated amount of sterile NaCl was applied to the palatal mucosa three times a week for 26 weeks. The L-AA supplement group with the lowest concentration (0.33 g/l L-AA) achieved mean plasma levels of 7 +/- 1.38 microM, approximately one-eighth that of the normal level (mean plasma L-AA level in outbred Wistar rats was found to be 58 +/- 3 microM) whilst those in the higher supplement group (3.33 g/l L-AA) achieved a mean of 18 +/- 1.25 microM. All of the animals employed in the present study survived for 26 weeks and showed no clinical signs of L-AA deficiency during this period.

Expression of c-erbB-2 protein in keratinocytes of oral mucosal lichen planus and subsequent squamous cell carcinoma.

Oral mucosal lichen planus (OMLP) is a well recognized mucosal disease with unknown etiology. Considerable controversy exists as to whether OMLP is intrinsically premalignant, or if the disorder facilitates the development of oral mucosal squamous cell carcinoma (OMSCC) by external factors. The aim of the present study was to investigate the expression of c-erbB-2 protein in the keratinocytes of initial biopsies or oral mucosal disorders diagnosed as OMLP with no evidence of epithelial dysplasia, and to compare the results with the expression of c-erbB-2 protein in subsequent biopsies obtained from the same patients. These results were compared with the findings from control groups (patients with dysplasia with no evidence of OMLP, patients with OMSCC with no evidence of OMLP and normal oral mucosa). The expression of the c-erbB-2 protein was evaluated by immunohistochemical staining of the gene product with the avidin-biotin-complex method using paraffin-embedded tissues sections. Five of the initial biopsies from patients with OMLP expressed the c-erbB-2 protein and one did not. None of the OMLP cases that subsequently showed evidence of dysplasia expressed the c-erbB-2 protein, and of the three OMSCC specimens from the patients with OMLP, two were negative and one expressed c-erbB-2 protein. The specimens from the control groups all expressed the c-erbB-2 protein. The results indicated the probability of the absence of c-erbB-2 staining being an indication of a potential for neoplastic transformation in OMLP with dysplastic changes.

Nuclear morphometry in experimental oral mucosal carcinogenesis.

The area, perimeter and diameter of basal cell nuclei of rat palatal epithelium were measured and the deviation of the basal cell nuclear profile from the form of a sphere was assessed after the application of the carcinogen 4-nitroquinoline-1-oxide (4NQO). After a 24-week treatment-free period, designed to eliminate the irritant effect of the carcinogen, the rats were killed, the palatal mucosa was recovered and processed and the nuclear histometry was assessed with image analysis techniques. The basal cell nuclear area increased as the epithelium became dysplastic and then decreased as carcinoma developed, but there were significant variations in this parameter in the control groups. Basal cell nuclei from moderately or severely dysplastic epithelium, and from epithelium adjacent to areas of invasive carcinoma, were significantly less regular in profile by comparison with control nuclei. Variations in nuclear profile, but not nuclear area, perimeter or diameter, might reflect fundamental nuclear alterations of significance during the process of carcinogenesis.

The prognosis of oral mucosal squamous cell carcinomas: a comparison of clinical and histopathological grading and of laminin and type IV collagen staining.

Changes in the distribution of basement membrane components have been described in dysplastic lesions and in oral mucosal squamous cell carcinomas (OMSCC). The purpose of this study was to determine if these changes were related to pathological grade and if so, whether this had prognostic implications. Fifty formalin-fixed, paraffin-embedded specimens of OMSCC, with five or more years clinical follow-up, were studied using an immunoperoxidase technique for the detection of the basement membrane components, laminin and type IV collagen. The immunoreactivity of each component was evaluated and semiquantitatively scored as minimal, moderate or extensive and the results compared with the tumour size, node involvement and metastasis (TNM) clinical staging system and histopathological features. OMSCC were characterized by minimal or moderate staining with small islands of neoplastic cells frequently lacking staining for laminin and type IV collagen. Deposition of these components decreased with increased histopathological grade and absence of staining was more commonly associated with a poor prognosis. In particular the pattern of type IV collagen staining frequently differed from laminin staining. Neither of these parameters offered an advantage over TNM clinical staging with regard to prognosis. It was concluded that variations in laminin and type IV collagen immunoreactivity occurred in OMSCC and that high histopathological grade tumours with considerably diminished staining with anti-laminin and anti-type IV collagen carried a poor prognosis.