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Biomedical subjects

T L Hansson

Publications and source records attributed to T L Hansson.

At least 37 records · Page 2Linked to original sources
PubMed1989

Short-term effect of a stabilization splint on the asymmetry of submaximal masticatory muscle activity.

Ten healthy subjects continuously wore equilibrated maxillary full-arch stabilization splints in the retruded position for 7 days. The muscular activity balance of the masseter muscles during submaximal isometric clenching at 10% and 50% of the maximum voluntary contraction (MVC) did not change immediately on insertion of the splint, but was improved at the 50% level after 7 days (P less than 0.05). While the muscular balance of the anterior temporal muscles was not affected, either immediately on splint insertion, or after wearing it for 7 days, temporal muscle activity at 10% of the MVC was greater on the side to which the mandible moved from the retruded contact position (RCP) to the inter-cuspal position (ICP), both before (P less than 0.025) and after (P less than 0.01) wearing the splint. Splint removal after 7 days resulted in increased awareness of interferences in the ICP and increases in masseter muscle asymmetry (10%, P less than 0.025; 50%, P less than 0.05) when the electromyograms in the ICP after splint removal were compared with those on the stabilization splint before removal. After wearing the splint, the masseter muscle activity at the 10% level was greater on the side where premature contacts were present in the RCP (P less than 0.01). The use of masticatory muscle asymmetry indices in the evaluation of splint treatment for craniomandibular dysfunction is indicated since submaximal masticatory muscle activity is related to occlusal stability, premature contacts in the RCP and the direction of lateral slides from the RCP to the ICP.

Adaptation, Physiological↗
PubMed1989

The recognition of craniomandibular disorders; condylar symmetry in relation to myogenous and arthrogenous origin of pain.

Sixty-seven per cent of the forty-three patients suffering from craniomandibular disorders (CMD) had a vertical condylar asymmetry greater than 3%. After division into two different groups, myogenous and arthrogenous origin of pain, it was found that myogenous patients were younger and showed significantly bigger asymmetry between the vertical heights of the left and right condyles, evaluated on an Orthopantomogram, than the patients with arthrogenous origin of pain (P less than 0.05). The mean vertical condylar asymmetry was 9.10% and 4.83%, respectively. It is suggested that the possible triggering morphological condylar asymmetry on the pathogenesis of a CMD should be recognized at an early stage of the disorders development. The use of a screening protocol and an Orthopantomogram could be of preventive importance in daily practice.

Adolescent↗
PubMed1989

The recognition of craniomandibular disorders--an evaluation of the most reliable signs and symptoms when screening for CMD.

Two hundred and twenty-two patients who had been examined and treated for craniomandibular disorders were re-evaluated using a screening protocol. This protocol was developed from previous studies which had elucidated the most reliable signs and symptoms of craniomandibular disorders. Unilateral signs and symptoms were found to be more common than bilateral signs and symptoms. Dynamic and static pain tests were shown to be decisive in determining the preliminary diagnosis. There was a significant difference in vertical condylar height asymmetry between those patients diagnosed as having a myogenous and an arthrogenous origin of pain.

Adult↗
PubMed1989

The OPG: an aid in TMJ diagnostics. III. A comparison between lateral tomography and dental rotational panoramic radiography (Orthopantomography).

In the comparison of radiographical findings (flattening, irregular surface and osteophyte formation) between lateral tomography and Orthopantomography in thirty-one female patients with craniomandibular disorders, a 76% similarity was found. A trend in the findings was seen: with an increase in radiographical findings visible in the tomograms there is a decrease in the amount of condylar asymmetry visible in the Orthopantomograms and a decrease in the age of the patients.

Adolescent↗
PubMed1989

Balance in masticatory muscle activity during natural chewing and submaximal clenching.

The balance in the electromyographic (EMG) activities of the left and the right masseter and the left and right anterior temporal muscles during chewing and during submaximal clenching at 10% and 50% of the maximum voluntary contraction in the inter-cuspal position was investigated in twenty healthy adults. Muscular asymmetry patterns during chewing and clenching were positively correlated for both pairs of masticatory muscles investigated at the 50% level (P less than 0.01-P less than 0.001) and for the masseter muscles, also at the 10% level (P less than 0.01). Stronger correlations in muscular asymmetry were found for the masseter muscles and at the higher submaximal clenching level. In general, the masseter muscles displayed a greater degree of asymmetric activity than the anterior temporal muscles during both chewing and clenching (0.05 less than P less than 0.1-P less than 0.025). The average EMG amplitudes of both masseter or both anterior temporal muscles within each subject showed no correlation between clenching and chewing. The correlations between muscular asymmetries observed during static (clenching) and dynamic (chewing) conditions suggest that there are common factors influencing these activities.

Adult↗
PubMed1989

Craniomandibular disorders in headache patients.

Fifty patients with recurrent headache who had been referred to a neurologist were randomly invited for an examination of their stomatognathic system. The prevalence and distribution of the findings in many ways resemble the clinical findings in CMD patients. In 66% of the patients, a myogenous or arthrogenous origin of CMD pain could be detected. Headache occurred more bilaterally, but unilateral findings were more common at the functional examination. The results did not show any statistical differences between the sexes.

Adult↗
PubMed1989

Temporomandibular joint clicking: a literature overview.

In view of the literature, it can be stated that too little is known about the prognosis of TMJ clicking, factors determining the need for treatment, and long-term results of therapy. Consequently, there is a need for more standardized research, leading to classification of the various types of clicking and knowledge about changes in the course of time.

Auscultation↗
PubMed1988

The recognition of craniomandibular disorders--a comparison between clinical and radiographic findings in eighty-nine subjects.

A comparison has been made between clinical and radiographical findings in a study of eighty-nine patients suffering from craniomandibular disorders. In general it was found that condylar changes were more common in these patients than in earlier studies concerning the severe problems of craniomandibular disorders. A statistically significant correlation between clinical and radiographical findings was found for crepitation with osteophyte formation of the condyle (P less than 0.01). After clinical separation of the patients into two groups based upon the origin of pain, myogenous versus arthrogenous, no radiographical correlation could be made except for condylar osteophytes. With the clinical method used for separation of patients it was found that the clicking of the temporomandibular joint (TMJ) was more common among myogenous patients (P less than 0.05); crepitation was more common among arthrogenous patients (P less than 0.01), as was limited mouth opening (P less than 0.05) and deviation on opening (P less than 0.05). Radiographically, the only statistical difference between the two groups was found for osteophyte formation of the condyle, this was more common among arthrogenous patients (P less than 0.05). As the clinical method has been tested earlier, the results of this study lends support to the idea that conventional radiographical examination is of limited use in the initial diagnostics of craniomandibular disorders. Therefore new alternatives have to be developed.

Facial Pain↗
PubMed1988

The Orthopantomogram, an aid in diagnosis of temporomandibular joint problems. II. The vertical symmetry.

Vertical measurements of the Orthopantomograms of 152 patients were made for condylar and rami heights. The symmetry between the right (R) and the left (L) side was calculated with the formula: [(R-L)/(R + L)]. A statistically significant difference between the patients of a routine dental group and the patients treated for craniomandibular disorders was found regarding condylar height symmetry.

Adult↗
PubMed1988

The recognition of craniomandibular disorders--a comparison between clinical, tomographical, and dental panoramic radiographical findings in thirty-one subjects.

A comparison between clinical, tomographical, and dental panoramic radiographical findings was made in thirty-one female patients suffering from craniomandibular disorders (CMD). In general it was found that condylar sclerosis was more common in these patients than in earlier studies. After clinical separation of the material into two groups based upon the origin of pain, myogenous versus arthrogenous, no radiographical confirmation of the differential diagnostics could be made. Regarding vertical condylar asymmetry measured on the Orthopantomogram, it was found that 74% of the patients with CMD had more than the 3% of asymmetry regarded as within normal limits. It seems that with an increasing severity of the disorder the level of condylar asymmetry appears less. If the interpretation of the findings is correct its conclusion might lead to the recognition of a morphological factor which could contribute to the development of a craniomandibular disorder.

Adolescent↗
PubMed1987

Histomorphometry of age and sex changes in mandibular condyles of young human adults.

Changes in cartilage, subchondral bone and their interface were studied using sagittal (6-8 micron thick) sections from the lateral, central, and medial parts of 21 condyles (11 males and 10 females; aged 18-36 years). The presence of undifferentiated mesenchymal (UM) cells in the proliferative zone of the cartilage was noted. Five condyles were judged to be immature because they had hypertrophic cartilage, cartilage resorption and bone formation at the cartilage-bone interface, no compact bone in their anterior and the superior regions, and the many cartilage rests in subchondral bone. Four of these immature specimens were from males. Immature specimens had quantitatively thicker cartilage (p less than 0.01), thinner subchondral bone (p less than 0.005), and less bone, more vascular spaces and more cartilage rests, both at the cartilage-bone interface and in the subchondral bone (p less than 0.001). Of the 16 mature condyles, the older had fewer UM cells in the proliferative layer, thicker compact bone (p less than 0.05), less vascular spaces at the cartilage-bone interface (p less than 0.05) and more bone and less vascular spaces in the compact bone (p less than 0.05 and p less than 0.01 respectively). No significant differences were found between mature condyles of males and females, but females had more UM cells, less hyperplastic cartilage and fewer irregularities at the cartilage-bone interface.

Adolescent↗
PubMed1987

Mandibular border positions and their relationships with peripheral joint mobility.

Peripheral joint mobility was assessed in a group of fifty-one dental students using a modification of the Carter and Wilkinson Index. Mandibular border positions were measured both actively and passively with the aid of a millimetre ruler. The purpose of the investigation was to study possible relationships between generalized joint (hyper-)mobility and (hyper-)mobility of the temporomandibular joints. Only a few weak correlations were found between the mandibular border position measurements (active and passive mouth opening, active and passive, left and right, laterotrusions and active protrusion) and the peripheral joint mobility measurements. Differences between the sexes were illustrated in peripheral joint mobility with females showing a greater joint mobility than males, especially when only the passively measured joints were considered. The mandibular border positions were significantly correlated with each other (P less than 0.05-P less than 0.001) for the males, but few and then only weak relationships between these measurements could be found for the females in this group. The concept of temporomandibular joint 'end-feel' in relation to joint mobility is discussed.

Adult↗
PubMed1987

The orthopantomogram, an aid in diagnosis of temporomandibular joint problems. I. The factor of vertical magnification.

As an orthopantomogram provides bilateral information, it seems to be an efficient tool for screening for arthropathy of craniomandibular disorders. An experimental model was designed and constructed to resemble a human mandible. By changing the position of the model in the horizontal plane of the orthopantomograph, nine different images were analysed for changes of vertical magnifications. Emphasis was put on large parts of the mandible like the condyle. In positions that had been altered less than 10 mm from the originally centred position of the mandible in the orthopantomograph, vertical differences between the left and right sides were less than 6%. Observed condylar asymmetries within a 6% difference might, therefore, be due to technical failures.

Humans↗