The effect of occlusal relationships on the occurrence of sounds in the temporomandibular joint.

The aim of this investigation was to determine the influence of occlusal relationships on the occurrence of sounds in the temporomandibular joint. A group of 100 male subjects aged 24-52 years (X = 35.03+/-6.92) was examined. Analysis of occlusion included determination of the number of existing teeth, number of teeth in occlusion, overbite and overjet, type of occlusion, mediotrusion interferences, relationship of the retruded contact position (RCP) to intercuspal position (ICP), and the amount and direction of sliding from RCP to ICP. Sound was registered by means of a stethoscope and classified according to its character in click or crepitation. Sound was present in 29% of subjects. In 28% of cases it was registered as click and in 2% of cases as crepitation. One subject had simultaneous click and crepitation. The results of the statistical analysis indicate that overbite, type of occlusion, existence of mediotrusion interferences, the relationship of RCP to ICP, and the amount and direction of sliding from RCP to ICP do not have an influence on the occurrence of sounds. The risk of the occurrence of crepitation is significantly increased in the case of the loss of more than 5 teeth, and in the case of horizontal overbite larger than 7.5 mm (p<0.05).

Three-month change in the radiodensity of alveolar bone supporting partial-denture abutment teeth.

This study uses the intraoral microdensitometric method to examine the impact of masticatory pressure on the alveolar bone around the abutment teeth clasp. Two retroalveolar radiographs were carried out on all 30 subjects over a period of 3 months using a copper calibration stepwedge. The dental radiographs were digitized and converted into positive. Grey level values on dental radiographs in the alveolar bone area in 7 region of interest (ROI) were measured. They were converted into the equivalent thickness of the calibration stepwedge using mathematical methods and the difference of the bone density between the two radiographs was calculated. The results demonstrated that there were no statistically significant differences between the 1st and 2nd radiographs in any of ROI (p > 0.05).

Evaluation of craniometric methods for determination of vertical dimension of occlusion.

In clinical practice, fully precise method for exact determination of vertical relation of occlusion still does not exist. This study examines the relationship between different craniofacial distances and the distance subnasale-gnathion (Sn-Gn), which represents the lower third of the face in vertical relation determination. The highest coefficient of correlation was (r = 0.8678, p < 0.05) between the distance eye-ear (E-E = lateral border of the ocular orbit-medial opening of the meatus of the external auditory canal) and Sn-Gn. The prediction of the distance Sn-Gn could be determined through the formula: Sn-Gn = E-E/1.08 or through the regression analysis: Sn-Gn = 1.9197 + 0.6449 x E-E. None of the calculated coefficients of correlation was 1, but was < 1, so that the prediction of the distance Sn-Gn by craniometric distances is not absolutely reliable, although it is considerably helpful. Our results point at the variations of craniofacial distances in the Croatian population. Yet, craniometry could still be recommended in everyday clinical practice for prediction of vertical relation of occlusion, as it is a simple, economic and non-invasive method, however in combination with some other methods, which have proved to be helpful.

Kineziographic research of patients with cross bite.

The paper describes the use of an objective method for the quantitative analysis of the relationship between the posterior cross-bite and the occurrence of occlusive interferences and damages to the mandible muscle elevator. Two groups of subjects were selected for the analysis: 10 patients with unilateral cross-bite and 10 students without any symptoms of temporomandibular disorders (TMD). By means of the Robert Jenkelson K5A kinesiograph we measured maximal opening velocity of the mandible (mm/s), maximal-closing velocity (mm/s), first tooth contact velocity and displacement in the vertical plane at the maximal intercuspidation (mm). The following values were obtained: maximal-opening velocity in the first group was 349 mm/s and 380 mm/s in the control group. This difference was incidental. The maximal closing velocity in the study group was 204.9 and 345.2 in the control group (p < 0.05). The first tooth contact velocity in the study group was 75.93 and 325 in the control group (p < 0.01). Displacements in the vertical plane at the maximal intercuspidation in the investigated group was 0.24 +/- 0.01 mm, while in control group that value was 0.12 +/- 0.012 mm.

The patient's and the therapist's evaluation of complete denture therapy.

A total of 222 patients were studied. In a questionnaire patients graded their complete dentures of different age and quality, depending on the level of satisfaction, using the modified analogue-visual scale from 1 to 5. The dentist assessed the same dentures, as well as the denture bearing area. The patients' assessments were surprisingly high, the grades were bigger than the therapist's (p < 0.05), but in disappointed patients the grades were smaller than the therapist's (p < 0.05). It seems that the dentist is more critical in assessments than the patient. No significant difference existed between chewing and denture stability and between stability and the comfort of wearing lower full denture (p > 0.05). Unstable denture aggravates chewing and causes pain and discomfort on the bearing area. It seems that subjective factors in patients, expectations of the denture or the number of previous dentures play a role in satisfaction, not only the quality of denture bearing area and the quality of a denture.