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Biomedical subjects

A W Haddad

Publications and source records attributed to A W Haddad.

6 recordsLinked to original sources
PubMed1979

Tissue damage from electrosurgical power output variations in hamster tongues.

An investigation was designed to determine the differences in the amount of tissue damage produced by variations in the amount of cutting power delivered to the hamster tongue with electrosurgery. By dividing the power of an electrosurgical instrument into 5 W intervals, from the lowest setting which would produce a cut up to the 50 W setting, histometric comparisons were made in the hamster tongue. Histologic analysis showed the following: 1. The 30 W power interval produced less tissue damage than any other power interval. 2. The 25 and 35 W intervals produced significantly greater damage than the intervals from 40 thorugh 50 W. 3. Histologically the experimental defect showed an area of coagulation necrosis approximately 50 mu wide along the margin of the incision. Tissue damage decreased laterally and inferiorly from the surface of the defect except at the 30 W setting, where the damage in the epithelium and the damage in the connective tissue were essentially equal. 4. There is some validity to the sparking-dragging test for setting the power interval of an electrosurgical instrument. 5. Higher power values which produce excessive sparking should be avoided by the clinician during electrosurgery due to the imprecise nature of the clinical incision.

Animals↗
PubMed1978

Histologic evaluation of electrosurgery with varying frequency and waveform.

This investigation was designed to determine the differences in tissue alteration produced by electrosurgical machines with different carrier frequencies and waveforms. Histologic analysis showed that: 1. The machine with full-wave rectification and the lowest frequency of operation (machine I, 1.7 MHz) produced significantly greater tissue alteration in the superficial tissue layers than the full-wave rectification machines with higher frequencies of operation. 2. The continuous-output waveform produced significantly less tissue alteration in the superficial tissue layers than the modulated type at the same frequency of operation. 3. Histologically, the experimental defect showed a band of coagulation necrosis approximately 50 mu wide along the margin of the incision. Tissue destruction decreased laterally and inferiorly from the surface of the defect. 4. The experimental defect was similar in shape to the physical form of the cutting electrode.

Animals↗
PubMed1976

Stresses created by occlusal prematurities in a new photoelastic model system.

A new photoelastic model system incorporating a simulated periodontal ligament sleeve around an experimental first molar has been developed. The system was used to visualize internal compressive stresses created by various premature occlusal incline relationships in both buccolingual and mesiodistal dimensions. When prematurities were applied singly and observed buccolingually, both class 1 and and class 2 prematurities produced stresses along the lingual aspect of the root, whereas the class 3 prematurity produced stresses along the buccal aspect of the root. When viewed buccolingually, combinations of class 1 and class 2 prematurities resulted in stresses along the lingual aspect of the root. The stress pattern was similar to those created by the single class 1 or class 2 prematurities. A combination of class 2 and class 3 prematurities did not produce a well-defined indication of stress distribution. There was slightly more stress along the buccal aspect of the root. Comparison of this combination with individual class 2 and class 3 prematurities indicates that such a combination tended to diminish tipping of the tooth in any one direction. A combination of class 1 and class 3 prematurities showed slightly greater stress along the buccal aspect of the root surface. Again, the combination produced less tipping of the tooth in any one direction when compared with tipping caused by the individual prematurities. When all three prematurities were tested at the same time, the stress pattern was almost coincident with that achieved in the absence of prematurities. When prematurities were observed mesiodistally, the location of stresses was dependent on the mesial or distal placement of the prematurity, irrespective of its position buccolingually.

Dental Occlusion, Traumatic↗