PubMed Health⌕ Search

Biomedical subjects

F W Roeber

Publications and source records attributed to F W Roeber.

16 recordsLinked to original sources
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↗