Biomedical subjects

N Brill

Publications and source records attributed to N Brill.

At least 37 records · Page 2Linked to original sources

PubMed1978

Age changes in the perception of comfortable mandibular occlusal positions.

It has been shown that a zone of comfort in maxillo-mandibular relationships in edentulous subjects can be identified with some precision. Whilst the neurophysiological mechanism involved has not been explained fully, the phenomenon is influenced by starting position and by fatigue. This experiment was set up to test the hypothesis that age is another significant factor in perception of the comfortable zone. A group of seventeen subjects with a mean age of 62 years and an equivalent younger group, the mean age of which was 28 years, were tested with Timmer screw jacks applied using the central approach to record the upper and lower limits of the zone fifteen times in succession for each subject. A linear statistical model was used to analyse the data from upper and lower borders separately. The results showed that the effect of making successive adjustments, whilst not significant statistically in the young group, was significant in the more elderly. Regression lines from the young group data were horizontal signifying the high degree of accuracy with which their perceptual mechanisms worked: the upwards inclination of those from the more elderly was interpreted as showing that initial appreciations were subjected to constant correction.

Adolescent↗

PubMed1977

Ecologic changes in the oral cavity caused by removable partial dentures.

1. The introduction of a removable partial denture into the oral cavity adversely affects the prevailing ecologic situation in terms of plaque formation. 2. The rehabilitative effect of a removable partial denture may be safeguarded by controlling plaque formation by strict personal hygienic measures on the part of the patient. In particular, proximal surfaces adjacent to denture bases should be pointed out to patients as surfaces to which they must give special attention. 3. Simplification of the design of removable partial dentures can reduce their damaging potentialities. 4. Further prophylactic measures, such as topical application of fluorides and perhaps other chemicals, should also be taken.

Adult↗

PubMed1977

Short-term changes in the perception of comfortable mandibular occlusal positions.

In search of a new clinical method for determining the occlusal height of full dentures, the perception of the comfortable zone was studied in fifteen edentulous patients. In each experimental session perceptual changes were recorded from forty-four consecutive applications of a screw jack per subject. Two stages in perceptual acuity were found. An initial stage, in which only minor variations occurred among the final screw adjustments which the subjects made when they assessed the borders of the comfortable zone. In the ensuing stage greater variations emerged, indicating a deterioration in the ability of the subjects to discriminate.

Aged↗

PubMed1977

A new intra-oral screw jack.

A new pattern of screwjack for assessing the vertical dimension for occlusion utilizing an edentulous patient's proprioceptive sensation is described. It provides a greater range of movement than other, giving infinitely variable heights between 9 and 21 mm. The elements being captive, it cannot come to pieces in use. Laboratory experiments were contrived to define the magnitude of reading errors and the play in the screw threads. It was found that, only in instances where a graduation related closely to the datum mark, did errors of interpretation arise. These were found to exceed the height set for test purposes by 0-1 mm consistently. An error of this order is of no practical significance clinically and is no impediment to such an application of the device. Mean play in the new pattern jacks was 0-01 mm compared to 0-05 mm in the Timmer versions. In a clinical experiment the performance of the screw was compared to that of Timmer. Statistical evidence was found which suggested a functional difference between the two, the new pattern being significantly more accurate.

Aged↗

PubMed1977

A comparative study of three different approaches to the comfortable zone.

By means of a screw jack device, applied to thirteen edentulous subjects, the comfortable zone was approached in three different ways, by the central, the internal and the external approaches. Correspondingly, the zonal borders behaved differently. Applying the central approach it was found that the initial height of the screw jack had a lingering effect upon subsequent adjustments of the screw. Moreover, lower border data collected by the external approach distinguished themselves from other zonal border data by showing a significantly lower susceptibility to successive adjustments. The study suggests that muscle activity is a factor on which the perceptual mechanism relies, when a zonal border is assessed subjectively by a patient.

Aged↗

PubMed1976

The fallacy of facial measurements of occlusal height in edentulous subjects.

A controlled trial was made using fifteen subjects and making 120 measurements with a caliper gauge between marks disposed on the upper lip and the point of the chin when maxillo-mandibular relationships were altered vertically by known amounts within a range of 6 mm. It was found that mean facial measurements could account for only half of the skeletal movement involved. The variability of soft tissue translation in relation to skeletal movement led to the conclusion that such facial measurements are inappropriate to clinical practice.

Adult↗

PubMed1976

The linear model: a statistical tool applied to psychophysical research in dental prosthetics.

The construction of a linear model is described, and its function in analysing variations in the perception of comfortable mandibular occlusal positions is explained. In principle, the model combines analyses of variance and regression in a number of simple computer operations. Data from a clinical study were used to demonstrate the analytical capacity of a specific model, designed to estimate the effect of factors, which were supposed to influence the perception of comfortable mandibular positions.

Adult↗

PubMed1974