摘要:

summaryA model that describes the mechanics of jaw opening and the associated movements of the disc in a healthy human temporomandibular joint is used to explain the abnormal movements associated with internal derangement of the joint. A change in the constraints on jaw opening imposed by the accessory ligaments around the jaw joint can account for, among other things, clicks on opening and closing, disc displacement and replacement, and the conditions of open and closed lock.

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00216.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

summaryVertical asymmetry of the mandibular ramus and condylar heights was measured with a new method from dental panoramic radiographs. The study groups consisted of 45 psoriatic arthritis (PA) and 45 control (CO) matched pairs. Vertical asymmetry was calculated with the formulal |(R‐L)/ (R+L)|× 100. Females showed no statistical significant difference in vertical asymmetry between the PA and CO pairs. In males however, vertical asymmetry showed a statistically significant difference between the PA and CO groups among those aged 35–55 years (P=0.008). This group included four men with arthritis mutilans, a severe form of psoriatic arthr

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00217.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

summaryThe effects of stabilization splints on the electromyographic activity patterns of the masseter and anterior temporal muscles during maximal clenching in healthy subjects and subjects with different types of stomatognathic dysfunction syndrome were investigated. No marked effect of splints on the asymmetry of muscle activity during bilateral clenching was revealed immediately after splint insertion. During unilateral clenching in the intercuspal position (ICP), the relative asymmetry index (rAI) of the masseter muscles, detecting the imbalance of left and right muscular activity, was significantry increased. The use of splints suppressed the asymmetry of masseter muscle activity during unilateral clenching. This result suggests that the use of a splint is a method of suppressing clench‐caused aggravation of stomatognathic dysfunction in the presence of an imbalance between left and right muscle activitie

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00218.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

summaryThough a number of laboratory models have been developed to study the effects of X‐ray geometry on the appearance and relative positions of anatomical landmarks, such as the amelocemental junction and alveolar crest, many have failed to take into account the three‐dimensional nature of the alveolus and its spatial relationships with the teeth. As a result, the findings of manyex vivoinvestigations must be questioned. The aim of this investigation was to develop and refine a new laboratory method for experimental dental radiography utilizing a series of anatomical radio‐opaque acrylic models containing extracted teeth. The method allows adjustment of the beam‐object relationship through the use of precision‐made wedges, which are able to tilt the models through a series of angles thus simulatingin vivochanges in both vertical and horizontal X‐ray beam angulation. The technique is capable of being used in studies involving assessment of alveolar bone height or the depth of carious lesions. The precision of the method was tested by radiographing in nine different positions a test device consisting of four small cylindrical amalgam fillings embedded in a perspex sheet. Following removal and replacement, exposures of the test device were repeated for each position. Five linear distances between pairs of fillings were selected and measured on each radiograph to give a total of 45 measurements per set of films. There was exact agreement in 39 of the measurements recorded and a discrepancy of ±0.1 mm in the remaining six. The estimated standard deviation for variation on repeat radiography was 0.258 and the 95% confidence interval 0.214 to 0.325. The precision of the apparatus was thus found to be adequate for the measurement of differences in sma

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00219.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

summaryHigh oral perception is thought to contribute to poor adaptation to new dentures. The aim of this study was to evaluate the oral stereognosis and tactile sensibility in edentate subjects and relate these to patient age and capability of adaptation to new prostheses. A total of 67 patients were provided with new complete dentures 2‐3 weeks before the experiment. In 54 subjects, the oral stereognosis was evaluated by 12 different test‐pieces, which were placed unseen on the tongue and had to be recognized. In 38 patients, the oral tactile sensibility was determined in the premolar area using copper foils. The capability of adaptation was evaluated by a questionnaire.Denture retention was assessed by clinical examination. The number of correctly identified test‐pieces and the average identification time were related to the age, but no relation was found to patients’capability of adaptation. The tactile sensibility was found to be impaired with age and diminished capability of adaptation. Both adaptation and oral tactile sensibility were significantly lower in subjects with poor lower‐denture retention. In conclusion, the results cannot support a relationship between high oral stereognosis and adaptation problems. However, good denture retention facilitates the adaptatio

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00220.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

summaryThe skin surface temperature (SST) over the masseter muscles was measured in 19 patients suffering from myofascial pain (MP) and 20 controls who had no history of any craniomandibular disorder. Seven measurements with intervals of 2 weeks were carried out. MP patients received an occlusal stabilization appliance during their second visit as their only treatment. Clinical symptoms, including muscle sensitivity to palpation, jaw movement and general feeling were evaluated at each visit and compared to baseline. The results indicated that SST in the control group remained almost unchanged throughout the study. In the MP group, the mean temperature decreased during the study after initial treatment. Accordingly, there was a probability of 88.5% that the occlusal appliance treatment in the MP group would cause a decrease of SST over the masseter muscle. A significant relationship between clinical improvement and a decrease of SST was found in the MP group. Temperature recordings with certain limitations could be an objective assessory tool in diagnosis and follow‐up of patients with myofascial pai

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00221.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

summaryThe aim of the study was to investigate the influence of stress on the open‐close activity in mastication, using an animal model. For this, we have compared the single‐motor activites of three muscles: anterior digastric (AD), anterior temporalis (AT) and the superficial masseter (MS) in different groups of rats classed according to emotional state and dental occlusion. The EMG graphs have been analysed by the method proposed by the Weijs&Dantuma (1975). The results show that a dominant action of the stress on the AD and a combined action of the stress and the occlusal state on AT and MS occur during a single mastication cycle. A supression of the reflex myotatic inhibition for AT and MS occured in the presence of an occlusal interfere

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00222.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY

摘要:

summaryA rigid intercuspal interference (minimum mean height of 0.24 mm) was placed on either the right or left mandibular second premolar and first molar of 12 subjects. During brisk and forceful biting on the interference, rotational electrognathography measured maximum torque of the right and left mandibular condyles in the frontal and horizontal planes of orientation. All subjects showed frontal plane upward rotation (mean of 0.7 degrees) of the mandibular condyle contralateral to the interference. In 33% of the subjects there was no horizontal plane rotation. In 58% of the subjects there was horizontal plane backward rotation (mean of 0.5 degrees) of the mandibular condyle ipsilateral to the interference, and in one subject (8%) there was backward horizontal plane rotation (0.1 degree) of the mandibular condyle contralateral to the interference. It was inferred that the masseter muscle, ipsilateral to the interference, generated negative work in order to decelerate frontal plane‘unseating’of the mandibular condyle ipsilateral to the interference. It was inferred that the masseter muscle, contralateral to the interference, produced positive work in order to accelerate frontal plane 'seating’of the mandibular condyle contralateral to the interference. Finally, it was speculated that the impact forces of frontal plane 'seating’of the mandibular condyle, contralateral to the interference, might lead to‘vacuum sticking’of the temporomandibular joint disc because of the formation of negative hydrostati

ISSN:0305-182X    

DOI:10.1111/j.1365-2842.1995.tb00223.x

出版商:Blackwell Publishing Ltd    

年代:1995

数据来源: WILEY