Evaluation of articular disc loading in the temporomandibular joints after prosthetic and pharmacological treatment in model studies

BACKGROUND

Temporomandibular joint dysfunction is often related to excessive load in the stomatognathic system.

OBJECTIVES

The objective of the model tests, using numeric calculations, was to assess the articular disc loads in the temporomandibular joints after prosthetic and pharmacological treatment of functional disorders of the masticatory organ.

MATERIAL AND METHODS

The study involved 10 patients, aged 21-48 years, of both sexes, randomly selected from a group of 120 patients treated with relaxation occlusal splints (60 patients, group I) and intramuscular injection of botulinum toxin type A (60 patients, group II), suffering from temporomandibular joint dysfunction with the dominant muscle component. In all subjects, a specialized functional examination was carried out. Treatment groups: occlusal splint therapy (group I) and intramuscular injection of botulinum toxin type A (group II). An assessment of the loads of 4 disc zones of the temporomandibular joints was carried out based on the results of clinical studies (phase I of the study), and numeric model tests (phase II). In the representatives of the study groups (5 patients in each group), measurements of occlusal forces and an evaluation of tension of the masseter and temporalis muscle were performed.

RESULTS

The results of the average load values for all evaluated zones of the right and left articular disc differ in a statistically significant way in favor of group II, with the exception of the external mid part of the discs. In the case of the anterior of the right disc, the load was lower in patients belonging to group I than in those obtained in group II.

CONCLUSIONS

Botulinum toxin type A significantly reduces the loads within the temporomandibular joints, generated by masseter muscle hypertonia.

The evaluation of the accuracy of shape imaging of prosthetic abutment

PURPOSE

The aim of the study was the in vitro evaluation of the accuracy of shape imaging of abutment teeth using different impression compounds.

METHODS

To compare the accuracy of the shape of the numerically imaged real prosthetic abutments with the tested models of abutments obtained with the replica technique, the Geomagic Qualify program was applied. Making use of the licensed program Statistica, statistical analysis of the results obtained was conducted.

RESULTS

In the research procedures, analyses were conducted for 10 abutment premolars and 10 abutment molars. The tests allowed us to state that the dimensional accuracy of the models of prosthetic abutments obtained with the application of elastic compounds tested ensures comparable shape imaging.

CONCLUSIONS

The objective method developed and applied here is suitable for controlling the imaging of the abutment teeth. The Geomagic Qualify program that was used during the research is a reliable tool of 3D analysis for the estimation of procedure of abutment tooth preparation and indication of an error of shape of prepared occlusal surface, lateral surface of abutment and errors of shaping the chamfer zone.

[Vertical pathological attrition--causes, consequences and treatment methods]

The mechanism of development of vertical pathological attrition leading to destruction of the palatine and vestibular surfaces of the anterior teeth is described. Vertical pathological attrition is most frequent in acquired occlusal defects after loss of abutement zones, and in certain congenital malocclusions (supraocclusion). This condition may lead to damage to the whole stomatognathic system. Depending on the degree of progression of the pathological changes of this system prosthetic treatment in cases of vertical pathological attrition may be done in one or two steps. For illustration of the methods of treatment of this attrition three cases are presented.

[The Cracow modification of the Calotte method of teeth placement in clinical evaluation]

The purpose of the paper was checking of theoretical principles and assessment of the clinical usefulness of the calotte method of teeth placement in Cracow modification. In 110 patients this study was carried out according to the following schema: prosthetic treatment using complete prostheses with teeth placed by the modified method or by the Gysi-Fischer method, for comparison, and periodically repeated clinical examinations considering such elements as: articulation and occlusion, fixation and statics of prostheses, masticatory function and speech, and aesthetic result and adaptation process. In all these parameters good results were obtained by the modified method. It is concluded that the modification is particularly useful in therapeutically difficult cases, with unfavourable anatomic-physiological conditions of the denture bearing area.

[Teeth placement in complete denture by the Calotte method in Cracow modification]

Theoretical principles and the modification of the calotte method of teeth placement in complete prosthesis are presented. The method combines the elements of the articulation and static theories, but is easy for teaching and introduction, is not requiring a change of the clinical management (in relation to the generally accepted principles) or use of special devices of articulators which are presently unavailable. Checking of correct teeth placement is also easy. The method is thus simplified and thus possible for application in laboratories with average technical equipment.

[Criteria of anatomo-physiological evaluation of the conditions of the prosthetic substrate and a review of the classification of edentulous mouth]

The criteria for the assessment of the conditions of the mouth for the needs of prosthetic treatment are presented and the classifications of edentulous mouth used as yet are surveyed.

[Review of the presently accepted theories of teeth positioning in complete prostheses]

The review paper describing the presently used principles of the theory of teeth positioning in complete prostheses. The author indicates their advantages and disadvantages, and the possibility of their application in general prosthetic practice.

[Results of toothlessness treatment by calottic method in the Cracow modification. Clinical studies]

The purpose of the paper was to control the new method of teeth positioning in complete dentures based on the modification of callottic method in clinical practice. Clinical studies depended on occlusion and articulation estimation, examination of denture statics, control of occlusion height and registration of the patients' subjective experiences. They concerned 81 toothless patients divided into 2 groups according to the specific classification and wearing complete dentures in which the teeth had been positioned according to the modified method and Gysi-Fischer' method. In the groups of patients under examination that had teeth positioned according to the modified method significantly better results of the values estimated than in comparative groups have been achieved. It has been found that using the modified method smooth OA surface of artifical teeth is obtained without necessity of its correction satisfactory denture statics is obtained and rehabilitation of mastication function and adaptation to the dentures take place in a short period of time.

[Prosthetic management in cases of generalized destruction of dental crowns]

Disturbances in stomatognathic system (ss) emerging as a result of generalized destruction of dental crowns of noncarious origin have been described in the article. Principles of two-stage rehabilitation of ss have been presented. Three own cases creating examples of two-stage prosthetic rehabilitation have been described.