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The author argues with the article of J. Bielski on the usefulness of using artificial teeth with flat masticating surfaces for complete dentures. Quoting the authors studying gnathophysiology and own studies as well as clinical observations he states that such prostheses may be a cause of stomatognathic system dysfunction.
The influence of reduced mastication on the pathogenesis of chronic gastritis was examined in rats. In spite of reducing experimentally the masticatory effect to a third no inflammation of the gastric mucosa was to provoke. Nevertheless, the attended group showed a significant smaller increase of weight during the experiment.
One hundred and twenty-seven dental undergraduates participated in a questionnaire survey containing questions relating to their experience with craniofacial pain, jaw function, oral habits and other predisposing factors. The prevalence of chronic habitual unilateral chewers (10%) in the above selected non-patient population was significantly lower than that reported in the patients suffering from craniomandibular disorders (CMD). Lateral masticatory preference was also shown to be significantly associated with symptoms such as "noises from the joints", "difficulty in opening the mouth wide", "an uncomfortable bite", "neckpains", "soreness in the teeth", "painful cheek muscles", "pain in the temples" and/or "tension in the muscles of the face and jaws". The interrelationship between unilateral mastication and CMD is discussed.
100 patients with pterygoid dental losses in the mandible randomly selected from the group of 900 patients have been examined. The material under examination has been divided into two groups (according to Kennedy's classification). I group--the persons with both-sided pterygoid dental losses, II group--the persons with one-sided pterygoid dental losses. Presence both extraoral and intraoral changes of the mastication organ in both groups as well as SSZ dysfunction symptoms has been analysed. The results obtained have proved that pterygoid losses essentially influence the presence of extraoral changes and less so the presence of intraoral changes. The span and type of dental losses have influenced the frequency of the presence of such changes as: cheeks' retraction, intensifying of nasolabial sulci, lowering of vertical dimension of the bottom face segment, attrition of teeth, presence of diastems in the maxilla and mandible, enlargement of the resting mouth silt etc. SSZ dysfunction symptoms have been found in 64% of the persons under examinations; intensification of these symptoms was positively greater in the patients with asymmetric losses, i.e. with one-sided losses. The examinations carried out demonstrate the need of all pterygoid dental losses restoration, particularly one-sided losses in the prophylaxis of mas-dysfunction generation.
The author established that during mastication of experimental silicon morsel the teeth get get in contact in 3/4 of the 32 subjects examined, with 6.25 close contacts on the average for each half jaw. The observations on the separate stages of masticatory cycle reveal that the morsel is turned round between dentition, cheek and tongue, and about 90 degrees the closing of dentition follows to contact, continued to the final fragmentation of the morsel.
When suckling of rats was continued on days 17--25 after birth, the development of the M. masseter superficialis was inhibited: increase in the diameter and SDH activity of its muscle fibers was retarded. Conversely, forced weaning of rats on 17 after birth stimulated the development of the muscle. These results suggest that mastication after weaning is involved in the further postnatal development of the M. masseter superficialis in rats.
PURPOSE: To evaluate the correlation between the gross imaging evidence of an aggressive masticator space (MS) tumor and the presence of such a MS malignancy. MATERIALS AND METHODS: Thirty patients were identified retrospectively who had a malignancy that either arose in or metastasized to the MS, had pathologic verification of the diagnosis, and had magnetic resonance (MR) and/or computed tomographic (CT) images. Specifically evaluated was the presence or absence of gross imaging evidence of mandibular erosion and the integrity of the medial MS fascia as evaluated by a smooth margin between this fascia and the parapharyngeal space fat. RESULTS: Of the 30 tumors, 28 were high-grade malignancies and 2 were histiocytoses. Of these, 5 had mandibular erosion and violation of the MS fascia, 19 had bone erosion with an intact fascia, 4 had neither bone erosion nor fascial violation (3 of these patients were under the age of 20 years), and 2 had fascial violation with no bone erosion. CONCLUSIONS: In 76.7% of patients with a malignancy arising in the MS, on imaging the medial MS fascia was grossly intact. There were 4 patients with MS malignancy and neither violation of the medial MS fascia nor mandibular bone erosion. Thus, these imaging findings may not be good criteria to evaluate the presence of a high-grade MS malignancy, especially if the patient is under the age of 20 years, in which age group MS sarcomas are more likely to arise.
In this survey, we identify the positive role that an instructional anatomy course has prior to a workshop on temporomandibular dysfunction. Not only did it result in enhanced clinical evaluation of the muscles of mastication acquired by the participants, but it also approximated the skills of dental and medical practitioners.
Three reports suggest that asphalt workers, especially young mastic asphalt workers, in Denmark experience an increase in incidence and mortality from cancer and in mortality from other conditions. The methodology described in these reports raises questions about their validity and the data presented are limited and difficult to interpret. The cancers and the causes of death that are increased are highly correlated with those seen among men in the general population who use alcohol in excess, who smoke, and who engage in other risk-taking behaviors. The effects of these lifestyle causes of disease were largely not controlled in the reported studies. These behaviors, which cluster in young men, rather than exposure to asphalt fumes, probably caused the disease patterns that were reported. Policy makers who use epidemiologic results for risk assessment and regulation should do so with care. Working men and women sometimes die at high rates and their occupational exposures may or may not be responsible. The distinction is crucial if occupational health is to be improved. If asphalt workers die young from excessive drinking and smoking, we are not protecting their health by controlling asphalt fume exposures.
The authors have shown, with the help of electromyography, the functional relationship which exists between the muscles of mastication and certain muscles of the leg after artificially creating interdental occlusal dysfonction. While the activity of the tibialis anterior was not affected by the alteration in occlusion, that of the peroneus longus and gastrocnemius was markedly changed. This is due to the activation of long muscle chains as a consequence of the activation of complex nervous reflexes.
When a lateral pterygoid muscle is more tender to palpation than the other muscles of mastication, and a stress test is positive, an occlusal cause should be suspected. Patients with lateral pterygoid tenderness are divided into three categories according to two criteria: the position of the condyles in their glenoid fossae and the degree of dysfunction in the articulation. Only patients in category 1, those with a centered condylar position and without dysfunction, are discussed in this article. Occlusal adjustment is executed on the basis of information gathered from radiographs of the temporomandibular joint, diagnostic casts, and leaf gauge measurements of unequal bilateral occlusal contact. The amount of tooth structure requiring removal can be determined by using leaf gauges of differing thicknesses. Occlusal adjustments are performed without mandibular manipulation until the tenderness of the lateral pterygoid muscle is relieved.
The sensory neurons in the trigeminal ganglion which project to the muscles of mastication of the cat were studied using the retrograde transport of horseradish peroxidase. Horseradish peroxidase either was injected directly into the masticatory muscles or applied to the nerves supplying them. Numerous retrogradely labeled neurons were found in the ipsilateral trigeminal ganglion. All labeled neurons were sequestered within the posterolateral (mandibular) portion of the ganglion, but the ganglion cells innervating individual muscles were not organized topographically. The diameter of the labeled neurons varied greatly and included profiles considered small, medium and large. The organization of the neurons in the trigeminal mesencephalic and trigeminal motor nuclei which project to individual masticatory muscles also was noted. It is suggested that many of the ganglion cells of small and medium size may be important for the perception of muscle pain from the masticatory muscles in the cat.
An open-top chamber study was conducted to investigate the tissue and cellular-level foliar effects of ozone (O3) on a Mediterranean evergreen species, the mastic plant (Pistacia lentiscus L.). Plants were exposed at three different O3 levels, and leaf samples were collected periodically from the beginning of the exposure. Although no visible foliar injury was evident, alterations of the plastids and vacuoles in the mesophyll were observed. Senescence processes were accelerated with an anomalous stacking of tannin vacuoles, and a reduction in the size and number of the chloroplasts. Overall, most of the modifications induced by O3 were consistent with previously reported observations on deciduous broadleaf species, with the exception of alterations in the cells covering the secretory channels, reported here as a new finding. Comments on the feasibility of using microscopy to validate O3 related field observations and subtle foliar injury are also given.
Mild degrees of asymmetry of the human body have been recognised both by classical sculptors and more recently by anatomists as both normal and widely occurring. Morphologic asymmetries of the face of a more severe nature are, however, quite rare. When such deformities occur, both the hard and soft tissues may be involved and the abnormality may be acquired as a result of trauma, infection, neoplasia or surgery or be of a developmental origin as in the syndromes affecting the first pharyngeal arch. Developmental asymmetries of the jaws may also arise as a result of unilateral disruption of mandibular development during the time of normal facial growth leading to hemiretrognathism. Severe hypoplasia of the muscles of mastication on one side only has not previously been reported.
Subdural empyema (SDE) is an extremely rare but serious complication of dental infection. A case is presented in which dental infection was complicated by a masticator space abscess and eventually led to a SDE. This report illustrates a rare sequence of events leading to SDE and its serendipitous detection by indium-111-labeled leucocyte scan.
Shortly after admission with facial space infection, ultrasound-guided needle aspiration of lateral masticator space abscess was carried out in 2 adult patients. One abscess was associated with pericoronitis and the other with post-extraction infection. Successful aspiration of pus was followed by an instantaneous improvement in the ability to open the mouth for a period of at least 24 hours. This obviated the need for conscious nasoendoscopic intubation and allowed orotracheal intubation for conventional drainage. We concluded that ultrasonography can be beneficial in the management of orofacial infections.
The sites of nerve entry and the intramuscular nerve branchings in the masseter, temporalis, medial and lateral pterygoid muscles were studied. A total of 55 muscles were taken from eight infants and only one adult subject. It was found that for each of the four muscles of mastication, the nerves entered at a nearly fixed point. The masseter and medial pterygoid have their origin, the temporalis very near to its insertion, the lateral pterygoid midway between its origin and its insertion. The intramuscular nerve branchings were investigated in the four muscles and, according to their relation to the direction of the muscle fibres, three patterns have been recognized. The results obtained were compared with those of other workers on other muscles.
Melioidosis is an infectious disease caused by a saprophytic bacterium, Burkholderia pseudomallei. It is endemic to Southeast Asia and Northern Australia. The spectrum of melioidosis in humans varies from sub-clinical to overwhelming protean manifestations resembling other acute and chronic bacterial infections. Disseminated septicaemia melioidosis presenting as a masticator space infection is reported here. This is germane to those treating diabetic patients with deep neck infections living in, or having visited, areas endemic for B. pseudomallei.