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PubMed1989

A profile of patients with temporomandibular disorders in Singapore--a descriptive study.

This is a descriptive study to establish the profile of 120 consecutive patients seeking relief from symptoms and dysfunction of the masticatory system at the Dental Clinic, Singapore General Hospital from February 1988-September 1988. The mean age of the patients was 29.4 years and females outnumber males by 2:1. The patients complained of TMJ clicking (66%), TMJ pain (55%), painful chewing (47%), headaches (42%), painful opening (37%), jaw locking (33%), and jaw muscle pain (23%). The possible etiological factors were recorded: macrotrauma (27%), stressful episodes (24%), unilateral mastication (53%), clenching (28%), grinding (26%) and excessive chewing habits (10%). Unilateral chewing was significantly associated with pain on opening (p less than 0.05) and joint pain (p less than 0.05). A statistical relationship was found between night grinding and laterotrusive wear of teeth (p less than 0.001). There was evidence that tension headache reported by TMD sufferers was related to temporalis muscle/tendon dysfunction (p less than 0.001).

Adolescent↗
PubMed1989

[Experimental studies on adaptation of mandibular masticatory movements to given laterally shifted intercuspal position].

When, the intercuspal position is newly established during reconstruction of maxillomandibular relationship, understanding the process of adaptation for the laterally shifted eccentric intercuspal position is very significant for problems involving maxillo-mandibular registration and diagnosis of occlusion, which has very important meaning for clarifying the neuromuscular control system for mandibular movement. In this studies, changes in clinical symptoms and masticatory movements were observed longitudinally when the laterally shifted intercuspal positions were newly established. Conditions for selecting four subjects were that they wore suitable overlay maxillary dentures connected to abutment teeth and that their mandibular dentition were natural and included good fixed restoration. Experimentally prepared overlay dentures were identical to those worn by subjects except that they included a structure of lateral shift of artificial dentition positioning to given newly laterally shifted intercuspal position. The condition of lateral shift of the intercuspal positions are established by the protrusion of the condyle on one side, amounts of lateral shift of the intercuspal positions were 0, 0.5, 1 and 2mm. From immediately after until a week after insertion of the experimental denture, observations were made to determine clinical symptoms and alterations in the chewing strokes on the frontal plane and in the rhythm of chewing movements. At first, the experimental denture with no lateral shift was inserted into the subject's mouth. Next, this was replaced by the experimental denture with a lateral shift of 1mm, and then this was replaced with a denture with a lateral shift of 2mm. When clinical obstruction was encountered, during this process this was replaced by one with a lateral shift of 0.5mm. Analysis of data of mandibular movement obtained was performed by means of a personal computer system. Results 1. Individual difference was observed in the process of adapting to laterally shifted intercuspal positions. One subject adapted adequately to a shift of 2mm, another to a shift of 1mm; and still another to a shift of 0.5mm. One subject failed to adapt adequately to a shift of 0.5mm. 2. When the laterally shifted intercuspal position was newly established, subject complained of a slightly high feeling in occlusion on the direction opposite to the lateral shift, occlusal sounds, and glide from the initial contact positions to the intercuspal position. All subjects, however, found it difficult to indicate the amount or direction of lateral shift; and there was no obstruction to intentional mastication under these conditions.(ABSTRACT TRUNCATED AT 400 WORDS)

Dental Occlusion↗
PubMed1989

[Densitometry of the bony structures of the human TMJ].

Four millimeter sagittal section of 65 formalin-fixed human TMJs were prepared. The X-rays of these specimen were evaluated numerically in a densitometer. The distribution of bone material and densities in condyle and fossa led to a classification of condylar and fossa types. In 48 specimen a combination of increased density of the condyle on the facial aspect with a thin bony lamella in the roof of the fossa, which either shows high density or very little material of low density, a so-called parchment fossa, was observed. The varying degrees of density as a function of mechanical stresses are discussed. The transfer of forces in the human TMJ during mastication exposes the superio-anterior or superio-facial segments of the condyle and the posterior slope of the articular tubercle to loading forces, while at the same time the roof of the fossa remains free of load.

Bone Density↗
PubMedDate not supplied

Recording of masticatory mandibular movements and velocity by an optoelectronic method.

In an assessment of the reproducibility of three-dimensional masticatory movements by an optoelectronic method, the tests conducted on the same individuals at different times produced results that were almost identical. However, some significant differences were found in the mandibular movement parameters when the subjects chewed different foods. This was mainly reflected in a longer opening time and higher values for the traversed 3D distance during mastication of chewing gum compared to peanuts. A movement analysis system was linked with a computer, and a program was developed for analysis of chewing parameters including mandibular velocity and dimensions. A reference system compensated for head movements. Every step in the recording procedure--calibration, collection, processing and presentation of the data--can be automatically controlled by the computer. The method proved to be precise and accurate in repeated recordings and apparently suitable for objective posttreatment and long-term evaluation of chewing performance.

Computer Systems↗
PubMed1989

[Paget's degeneration of the juxta-alveolar portion of the mandible in subjects with generalized osteoporosis. Clinical study].

After the description of the etiopathogenetic aspects and of the pathologic anatomy lesion more typical of the Paget's disease, the A.A. describe a interesting case of the mandible's degeneration in a patient with chronic osteoporosis. The patient does not masticate. The treatment has been to remodelling of the mandible. We made a scrupulous check of laboratory research and the radiographical, biological and histological reports to exclude osteosarcoma and gigantic cells tumour.

Calcitonin↗
PubMed1989

[Temperature loading of resin-bonded bridges and its effect on the composite strength of the adhesive bond].

Acid-etched prostheses are exposed in the oral cavity to pressure of mastication, to corrosion due to oral fluids, to changes in temperature due to ingestion, and to iatrogenic influences. The changes in temperature which were measured in the adhesive layer were up to +/- 40 degrees C within a range from -2 degrees C up to about 80 degrees C. The bonding agents, which had a high softening temperature and little thermal expansion showed the least influence of temperature after the in-vitro tests. The fact that the tested bonding agents are different in chemistry influenced significantly the adhesive and cohesive characteristics. The thermal tests lead to the conclusion that for clinical use the following adhesives are to be preferred: Bis-GMA modified by monomeric phosphate (e.g. Panavia) and Bis-GMA (e.g. Microfill pontic).

Adhesiveness↗
PubMed1989

Mandibular condylectomy in a horse.

Mandibular condylectomy was effective in improving mastication and stopping weight loss in a horse. The horse had a history of intermittent purulent drainage from a facial wound and unilateral ankylosis of the temporomandibular joint.

Animals↗
PubMed1989

The functional significance of the position of the centre of rotation for jaw opening and closing in the rabbit.

In the rabbit, jaw opening and closing occurs in combination with condylar protrusion and retraction. Consequently the centre of rotation (CR) for the movement lies in the inferior portion of the ascending ramus of the mandible, far below the condyle. This location is stable and independent of the type of food being chewed and the age of the animal. The topography of the soft tissues at the posterior border of the ramus is adapted to the movement pattern. The facial nerve crosses the space between skull and mandible at the level of the CR. The parotid gland lies behind the ramus between condyle and CR; below the CR, the gland is replaced by loose adipose tissue. A computer model was used to demonstrate that the location of the CR determines the amount of stretch of the large masseter and medial pterygoid muscles. Using parameters for passive elastic behaviour of muscle, obtained by postmortem measurements, it can be shown that the normal CR position minimises muscle stretch and passive elastic forces. Even a small upward displacement of the CR causes a significant amount of resistance in the jaw-closers at gapes comparable to those reached in natural mastication. A second, less dramatic effect of increased muscle stretch is a sharper decline of maximum possible active closing force, due to the interrelationship of fibre length and isometric tension. In young animals, the muscle fibres are relatively long but stiff; in adults they are shorter, but more compliant. In both ages the CR is located in such a way that masseter and medial pterygoid stretching is minimised. The high position of the temporomandibular joint ensures a maximal leverage for the muscles mentioned above. By separating the point where the reaction forces apply (the joint) from the location of the rotational axis, maximum leverage and minimal length changes of the jaw-closing muscles are achieved simultaneously. It is further suggested that elastic muscular forces play a role in determining the position of the CR.

Animals↗
PubMedDate not supplied

[Biochemical adaptation of the periodontium to changes in functional masticatory activity].

The activity of leucine amine peptidase, glutamate piruvate transaminase was increased and those of glutamate dehydrogenase and lactate dehydrogenase decreased locally in the region with functional traumatic overload and increased mastication activity (MA) in patients periodontium as related to that in patients with nonfunctioning link in dentition and reduced MA. ATR contents in patients with functional traumatic overload and generalized periodontitis was substantially increased as compared to those in other groups of subjects.

Adaptation, Physiological↗
PubMed1978

[Changes in the masticatory system in myasthenia gravis].

Myastenia gravis causes by a hypofunction of the striated musculature a variable motor dyscoordination, which was examined in 106 patients. Hypofunction alone does not have any periodontal consequences, caries intensity however was obvious. Incoordination caused by hypofunction often is the cause for TMJ damage. The increase in mouth opening and of masticating force by Tensilon therapy is a characteristic and diagnostically useful test for myasthenia patients.

Dental Caries↗
PubMed1979

[Prosthetic rehabilitation after loss of the tongue].

By fitting defect prosthesis, the act of swallowing, normalization of speech, and improvement in mastication were restored in many patients with tongue loss. The defect prosthesis also served to increase the volume and mobility of the tongue.

Deglutition↗
PubMed1988

[Correlations between masticatory performance in chewing gum method and occlusion as well as dento-facial morphology].

In order to examine the characteristics of the chewing gum masticatory test, the amount of sugar elution, the chewing time and the amount of sugar elution per second were measured in 109 young adults (93 males and 16 females), after 70 strokes of mastication. Their sex differences, differences among various occlusions, correlations with occlusal areas of the buccal teeth and correlations with roentgen cephalometrics were analyzed. 1. There was no sex difference in the amount of sugar elution. However, chewing time was shorter and the amount of sugar elution per second was higher in males than in females. 2. Compared with the normal occlusion group, the amount of sugar elution was significantly lower in the crowding and anterior cross bite groups (Inoue's classification), and in the Class III malocclusion group (Angle's classification) in males. The amount of sugar elution per second was also significantly lower in the crowding and anterior cross bite groups. However, significant differences could not be found for chewing time. 3. The amount of sugar elution per second was significantly correlated with occlusal areas in males and total samples. 4. The amount of sugar elution was significantly correlated with less than ANB and less than L 1 to MP in males, with less than L 1 to MP in total samples. The chewing time was significantly correlated with S-N, N-Me, N-ANS, S'-Ptm' in females. The amount of sugar elution per second was significantly correlated with less than SNA and less than L 1 to MP in males, and with A'-Ptm', Cd-Go, Go-Pog', Cd-Gn, less than SNA, less than L 1 to MP, less than MP-SN and gonial angle in total samples. 5. It is concluded that the chewing gum masticatory test is highly correlated with occlusion and dento-facial morphology. In particular, amount of sugar elution per second was thought to be a useful measure for masticatory performance in clinical orthodontics.

Chewing Gum↗
PubMed1988

Occlusal harmony and disharmony: frauds in clinical dentistry?

In defining the principles of occlusal function it is possible to demonstrate how firmly the number, the placement and the distribution of occlusal contacts control muscle activity and joint function during biting and chewing. This control implies that the intercuspal position is determined by positive feedback, that is by afferent activity that varies with occlusal stability. Conventional dental treatment involving occlusal surfaces alters this input and consequently alters the coordination of the muscles of mastication and the function of the temporomandibular joints. To assess and direct this input properly, quantitative parameters of electromyography and kinesiography are needed. Terms such as harmony and disharmony are irrelevant and must be abandoned.

Dental Occlusion↗
PubMed1988

Postnatal development of the mouse temporal muscle and effects of a fine-grained diet on the muscle spindle.

The postnatal development of the mouse temporal muscle and effects of a fine-grained diet on muscle spindles were investigated. On d 25 after birth, 3 types of extrafusal muscle fibers could be distinguished on the basis of SDH activity, but not on the basis of their diameters. And in 50-d-old mice, 3 types of the muscle fibers had different diameters each other. In intrafusal muscle fibers, the postnatal changes of the SDH activity were similar to those of extrafusal muscle fibers, but the diameter distribution showed unimodal statistical distribution from 10th to 50th postnatal day. On the other hand, in control 180-d-old mice, 80 percent of muscle spindles in the temporal muscle had complete annulospiral endings, but the ratio of muscle spindles with complete annulospiral endings was decreased significantly in mice fed a fine-grained diet. The diet also decreased the diameter of the endings significantly. These results suggest that the main changes in the morphological and functional properties of the mouse temporal muscle occur in during and early after weaning period, and that normal mastication is needed to maintain the homeostatic condition of the mouse temporal muscle.

Animals↗
PubMed1979

Cineradiography in odontology.

Using cineradiographic equipment with 35 mm film, the application of cineradiographic technique in odontology has been investigated with special reference to observation of bolus-position, the mandibular movement pattern, chewing velocity and the stability of full dentures. The study is divided in two parts. In the first part an assessment is made of the theoretical and practical error of the method and the radiation dose is determined. In the second part limited studies are performed on test-subjects before and after different types of oral rehabilitation. The mathematically estimated geometrical errors almost coincided with the results of the clinical test of the distortion and, together with the tracing error, were of such magnitude that high precision measurements were not possible. By using metal indicators the error could be reduced and movements or differences in the X-ray film greater than 1 mm could be observed with good accuracy. The absorbed dose was determined using the method of thermoluminescent dosimetry and was found to be approximately 5 rad for a cineradiographic investigation of the cranium. The studies of bolus position, mandibular movements etc. revealed, that after oral rehabilitation the patient's oral behaviour may change dramatically. New occlusal surfaces were in most cases used for mastication after a short period of adaptation after rehabilitation. The mandibular movement pattern was also markedly influenced. It is concluded that cineradiography is very suitable for observations of intra-oral behaviour, such as bolus position, and for functional movement analyses. For high-precision measurements other methods should be used.

Adult↗
PubMed1977

[The diagnosis of functionally induced disturbances in the region of the masticatory apparatus (author's transl)].

Functionally induced disturbances in the region of the masticatory apparatus are frequently due to occlusal interferences. The clinical investigation must not, however, be limited to testing the occlusion of the teeth alone; it includes the examination of the muscles of mastication and the mandibular joint. The exact investigation of the occlusion is performed by instrumental analysis of function. It is the method of choice for determining the position of the mandible. A recording of the findings ought to suggest the technical methods of investigation on which the diagnosis is based.

Female↗
PubMed1980

[Dietetic considerations of the peptic ulcer treatment (author's transl)].

Stated that the alimentary inconguities, the improper mastication and the quickly eaten of foods are to avoid for the direct irritant effect on the stomach, the authors have examinate the various dietetic treatments, imploied for peptic ulcer and they conclude that only during the acute clinical phase more restrictive regimens are necessary. When the patient in on way of recovery, the alimentation must be free in agreement to the tolerance and personal taste using more variety of food. Moreover it's necessary to remember that the patient is not an "ulcer", but "his ulcer" be treated with the psycho-pathological implication correlated.

Acute Disease↗
PubMed1984

Ontogeny of infantile oral reflexes and emerging chewing.

The ontogeny of rooting, lip, lateral tongue, mouth opening, biting, and Babkin reflexes and emerging chewing behaviors were observed in 2 normal infants from 1 week to 35 weeks of age. These behaviors were videotaped at 9 monthly test sessions, and their movement patterns analyzed during slow-motion playback. The reflex responses were elicited in both infants through 35 weeks of age. They consisted of those characteristic movements described in the literature plus additional movements that elaborated the characteristic pattern. The complexity of the reflexes and the quality of movement changed with age. Components of chewing, which emerged sequentially from 1 week of age, were cyclical mandibular elevation and depression, lateral tongue movements, transport of the bolus from lateral to medial oral position, mandible retrusion, lateralization and protrusion movements in association with mandibular elevation and depression, increase in speed of rhythmical chewing movements to the mature speed of 1 cycle per second, and mastication. Chewing and oral reflexes contained similar movements but differed in the relative frequency of certain characteristic movements and in the stimulus response relationship.

Child Development↗