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Biomedical subjects

M M Ash

Publications and source records attributed to M M Ash.

At least 55 records · Page 3Linked to original sources
PubMed1983

Correlations between EMG jaw muscle activity and facial morphology in complete denture wearers.

In a sample of fifteen partially edentulous subjects assigned for immediate complete denture treatment, a correlation analysis was performed between pre-extraction facial morphology determined from lateral cephalograms, and EMG activity of the anterior temporal and masseter muscles in maximal clench and tapping of teeth. Marked correlations observed between vertical and sagittal jaw relations and mean voltages of the jaw-closing muscles indicated strong biting activity in subjects with a square facial type. No significant associations were observed between biting strength and the age of the subjects. Correlations between facial morphological changes and changes in EMG biting activity after denture insertion and during 1 year of denture wear indicated that the anterior temporal muscles were extremely sensitive to sagittal changes in anterior occlusion. The masseter muscles were less sensitive, but responded in some instances to changes in vertical jaw relationship.

Adult↗
PubMed1982

An electromyographic study of jaw opening and closing reflexes in man.

The electromyographic activity of the right masseter and digastric muscles was recorded in 10 subjects. A jaw-opening reflex was observed shortly after a mechanical stimulation in subjects performing clenching and active jaw-opening exercises. The latency of this reflex activity was about 28 ms, coinciding with the termination of the silent period of the masseter muscle. The experiments show that this opening reflex can occur without masseter spindle-unloading and may respond to low-threshold afferents.

Adult↗
PubMed1981

Condylar cartilage: a scanning electron microscope study of anorganic mammalian condyles.

The mandibular condyles of four mammalian species (sheep, cat, monkey, and human) were rendered anorganic in NaOCl and examined by SEM. A mineralized cartilage front was identified in all specimens on the basis of a comparable morphology of chondrocyte lacunae and a calcospheritic pattern of mineralization. Species-specific differences in the cartilage surfaces were found to exist. The role of this cartilage in condylar remodeling and pathology is discussed. Attention is drawn to the fact that mineralized cartilage was identified on the articular aspect of all adult mammalian anorganic condyles examined.

Animals↗
PubMed1981

The effect of bite force on the duration and latency of the menton tap silent period.

The purpose of this research was to investigate the effect of bite force changes on the duration and latency of the menton tap silent period and particularly whether a decrease in bite force can increase the duration of the silent period to the extent which may be found in dysfunctional patients. The menton tap silent period was recorded from both anterior temporal and masseter muscles while the subject was clenching at different force levels. A bilaterally stable force transducer was used to monitor the clenching force. The results indicated no statistically significant differences in the mean durations and latencies of silent periods at different clenching forces. They suggest that duration and latency are not related to the degree of clenching force.

Adult↗
PubMed1981

The effectiveness of subgingival scaling and root planing in calculus removal.

The study presents an evaluation of the effectiveness of subgingival scaling and root planing related to depth of pocket and type of teeth. A total of 199 teeth in 25 patients were selected; 62 were scaled and 57 were used as controls. All teeth were initially scored using the calculus index of the P.D.I. (Ramfjord). Six surface locations were probed to determine pocket depth. The levels of the gingival margin were marked on the teeth to locate supra and subgingival calculus after extraction. The experimental teeth then were scaled. Both scaled and unscaled teeth were extracted immediately after the experimental procedures. The teeth were washed with water and stained with methylene blue. They were viewed under a stereomicroscope which had a tenth grid on its eyepiece. Percent of surface covered by calculus was assessed on both scaled and unscaled teeth. The results demonstrated a high correlation between percent of residual calculus and pocket depth. It was shown that pockets less than 3 mm were the easiest sites for scaling and root planing. Pocket depths between 3 to 5 mm were more difficult to scale and pockets deeper than 5 mm were the most difficult. Tooth type did not influence the results.

Dental Calculus↗
PubMed1981

Significance of occlusion in the etiology and treatment of early, moderate, and advanced periodontitis.

Elimination of lesions diagnostic of trauma from occlusion is an essential part of complete periodontal therapy and restoration of health in the masticatory system for such patients. This can be achieved by orthodontic treatment, temporary splinting, bite-planes, occlusal adjustment and permanent splinting of teeth. Occlusal therapy may be required during periodontal treatment for trauma from occlusion and to enhance occlusal stability at any stage of periodontitis, but is most often needed in advanced periodontitis. Splinting of hypermobility of self-limiting trauma from occlusion is not indicated. Splinting may be required in addition to occlusal adjustment in moderate to severe periodontitis when trauma from occlusion is progressive.

Animals↗
PubMed1980

Jaw muscle activity in complete denture wearers--a longitudinal electromyographic study.

EMG study of subjects wearing immediate complete upper and lower dentures revealed marked alterations in activity of the jaw closing muscles during the biting actions recorded. This finding suggests that changes in jaw and occlusal relationships due to resorption of residual ridges and settling of the dentures also affects jaw muscle activity. The relations between EMG and morphologic findings will be analyzed further in a separate article.

Adult↗
PubMed1980

Roentgen cephalometric analysis of ridge resorption and changes in jaw and occlusal relationships in immediate complete denture wearers.

In eighteen subjects assigned for immediate complete upper and lower dentures, roentgen cephalometric recordings were made before extraction of the residual anterior dentition and 3 weeks, 3 months, 6 months and 1 year after denture insertion. The cephalometric analysis was based on electronic measurements of linear and angular morphological variables and computer head plots generated from 177 reference points (Walker, 1967), derived for each subject for each of the five observation stages. The reduction of the alveolar ridges was most rapid during the first 3 months of denture wear and particularly during the post-extraction period of 3 weeks. The reduction in anterior height of the lower ridge was on average twice as great as that of the upper ridge. The ridge resorption and the accompanying settling of the dentures on the basal seats, measured from lead shots inserted in the dentures, brought about an upward rotation of the mandible with a resulting decrease in occlusal vertical dimension and reduction in overjet of the dentures. In accordance with the amount of ridge reduction, these changes showed great individual variation.

Adult↗
PubMed1979

The role of cutaneous receptors in the menton tap silent period.

The neuromuscular mechanisms of the electromyographic silent period are poorly understood but clinically significant. Our purpose was to isolate the contribution of cutaneous afferents from the chin to the latency and the duration of the EMG silent period. Under the conditions of our experiment, the afferents of the mental nerve have no observable influence on the latency or the duration of the silent period educed by a menton tap.

Adult↗