A new three dimensional system for comparative measurements of maxillomandibular relations
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DOI
Authors
Campos, Adeliani Almeida
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OA Version
Citation
Abstract
Better understanding of physiology of the masticatory system has led to the evolution of maxillomandibular centric relation concepts from mechanical to physiologically based concepts. The reproducibility of physiological methods for centric relation determination, however, has been criticized. In this clinical study the swallowing technique was modified and associated to an anterior jig (as advocated by Victor Lucia and modified by Okeson) to establish a physiological centric relation in a reproducible manner. Condylar positioning and reproducibility of the proposed Modified Swallowing Technique(MST) were compared to the same parameters of a traditional technique, i.e., Chinpoint Guidance Technique(CGT) with the same anterior jig. Both techniques were studied with the patient in the upright and supine postures. Three interocclusal records were obtained for each technique/posture combination from each of 30 patients. Casts were mounted and analyzed using the Three Dimension Analyzer, a newly developed instrument for three dimensional measurements of maxillomandibular relations at the condyle region in X(anteroposteriorly), Y(superoinferiorly) and Z(mediolaterally) axes. Maximum intercuspation served as the reference position for measurements. Results were analyzed using Analysis of Variance for repeated measures. There was a significant difference in condylar positioning between MST and CGT on the X (p=0.001) and Y (p=0.008) axes. 1n the upright posture MST positioned the condyles 0.28mm anterior, 0.26mm superior and 0.007mm right to CGT: In the supine posture MST positioned the condyles 0.22mm anterior, 0.16mm superior and, 0.006 right to CGT. In both postures, upright and supine, there was no significant difference in condylar position between techniques on the Z axis (p=0.78). In both postures MST placed the condyles in a more anterosuperior position than CGT what suggests a better seating of the condyles against articulating disk on the posterior slope of the articular eminences. Analysis of reproducibility of techniques in both postures revealed that MST reproduced condylar position within an area of +/- 0.14mm on X axis, +/- 0.16mm on Y axis and +/- 0.10mm on Z axis. Chinpoint guidance reproduced condylar position within an area of +/- 0.13mm on X axis, +/- 0.18mm on Y axis and, +/- 0.09mm on Z axis. There was no significant difference in reproducibility between MST and CGT on X, Y or Z axis (p>.05). (This research was supported in part by CNPq – Brazil, Grant 200326/ 91- 0).
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Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1994 (Prosthodontics/Biomaterials)
Includes bibliography (leaves 169-175)
Thesis (M.Sc.D.)--Boston University, Henry M. Goldman School of Graduate Dentistry, 1994 (Prosthodontics/Biomaterials)
Includes bibliography (leaves 169-175)
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This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.