Biomedical subjects

J J Huddleston Slater

Publications and source records attributed to J J Huddleston Slater.

6 recordsLinked to original sources

PubMed2000

Kinematics of the human mandible for different head postures.

The influence of head posture on movement paths of the incisal point (IP) and of the mandibular condyles during free open-close movements was studied. Ten persons, without craniomandibular or cervical spine disorders, participated in the study. Open close mandibular movements were recorded with the head in five postures, viz., natural head posture, forward head posture, military posture, and lateroflexion to the right and to the left side, using the Oral Kinesiologic Analysis System (OKAS-3D). This study showed that in a military head posture, the opening movement path of the incisal point is shifted anteriorly relative to the path in a natural head posture. In a forward head posture, the movement path is shifted posteriorly whereas during lateroflexion, it deviates to the side the head has moved to. Moreover, the intra-articular distance in the temporomandibular joint during closing is smaller with the head in military posture and greater in forward head posture, as compared to the natural head posture. During lateroflexion, the intra-articular distance on the ipsilateral side is smaller. The influence of head posture upon the kinematics of the mandible is probably a manifestation of differences in mandibular loading in the different head postures.

Adult↗

PubMed2000

[Treatment protocol for craniomandibular disorder 1. Diagnosis].

In two essays the treatment strategy of the department of Oral Function of the Academic Center of Dentistry Amsterdam for treating craniomandibular disorder (CMD) patients will be presented. This first essay starts with a short description of the symptomatology, classification and etiology of CMD. Then it is described how to diagnose a CMD with the use of a standardized diagnostic protocol. Some important aspects of the differential diagnosis of CMD are discussed. Furthermore it is discussed when a CMD-patient can be treated by the dentist or when referral to a CMD specialist or oral surgeon is necessary.

Craniomandibular Disorders↗

PubMed2000

[Treatment protocol for craniomandibular dysfunction 2. Treatment].

In two essays the treatment strategy of the department of Oral Function of the Academic Center of Dentistry Amsterdam for treating craniomandibular disorder (CMD) patients is described. In this second essay a description is given of several dental, physiotherapeutical and psychological treatment modalities for CMD. Then treatment strategies for the different categories of CMD are described. It is also indicated which aspects of the treatment strategy are based upon 'evidence based care' and which aspects are more based upon principles of 'common sense' and 'clinical prudence'.

Analgesics↗

PubMed1999

The intra-articular distance within the TMJ during free and loaded closing movements.

Previous studies on free opening and closing movements of the mandible have demonstrated that the opening movement traces of the condylar kinematic center (i.e., the condylar point for which the protrusive and the opening movement traces coincide) lie closer to the articular eminence than the closing traces. This indicates the presence of an intra-articular distance within the joint during free closing. Since the mandible behaves like a class III biomechanical lever, a counteracting mechanical load on the mandible during closing will press the condyle-disc complex against the articular eminence. Therefore, in this study the hypothesis was tested that the difference between opening and closing movement traces of the kinematic center is reduced when the closing movements are counteracted by a mechanical load. From 10 healthy participants, 20-second movement recordings were obtained by a six-degrees-of-freedom opto-electronic jaw movement recording system (OKAS-3D) for three types of movements: (1) free opening and closing movements, (2) free opening and loaded closing movements (i.e., the participants closed against a small or high manually applied downward-directed force to the chin), and (3) gum chewing. Off-line, the opening and closing movement traces of the kinematic center were reconstructed, and the average difference between the traces (the intra-articular distance) was calculated. The average intraarticular distance was significantly smaller during loaded closing than during free closing, whereas no significant differences were found in the intra-articular distances between the loaded situations of low and high manual loading and contralateral chewing (ANOVA and post hoc Bonferroni multiple comparisons of means test, p<0.005). In conclusion, loading of the mandible during closing movements reduces the intra-articular distance within the temporomandibular joint.

Adult↗

PubMed1999

Variation in movement traces of the kinematic center of the temporomandibular joint.

AIM: The purpose of this study was to compare the variation in movement traces of the kinematic center of the temporomandibular joint with that of 4 nearby condylar reference points. METHODS: Jaw movement recordings were made with an optoelectronic jaw movement recording system. Four asymptomatic participants performed 14 to 18 open-close mandibular movements. The movements were performed with deliberate alterations of the rotation/translation ratio during opening. The kinematic center of the condyle and 4 nearby condylar points (the corner points of a square placed in the condylar sagittal plane, centered around the kinematic center, and with an edge length of 10 mm) were used as reference points. The standard deviations in the downward displacements at the halfway point in the mandibular opening of these reference points were calculated as a quantification of the variation in the movement tracings of these points. RESULTS: The movement traces of the kinematic center showed the smallest variation in comparison to the traces of the 4 nearby reference points (2-way analysis of variance and subsequent contrast analysis; P = 0.0026). CONCLUSION: In comparison to 4 nearby condylar reference points, the movement traces of the kinematic center show the lowest sensitivity to variations in the way mandibular movements are performed.

Adult↗

PubMed1997

[Temporomandibular joint cracking: background and diagnosis].

Although patients often report painless clicking of their temporomandibular joint, treatment is not required. However, sometimes a clicking joint leads to a painful limitation of the movements of this joint. Why this happens is unknown. It is therefore recommended to monitor the clicking joint over time. Opto-electronic recording of condylar movements might offer additional possibilities in the assessment of clicking joints.

Electronics, Medical↗