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Biomedical subjects

R A Kopczyk

Publications and source records attributed to R A Kopczyk.

10 recordsLinked to original sources
PubMed1991

Physical characteristics of Ti-6A1-4V implants fabricated by electrodischarge compaction.

Physical characteristics of a Ti-6A1-4V implant were evaluated following fabrication using a new electrodischarge compaction technique. Ti-6A1-4V atomized powders were loaded into Pyrex tubes (3.3 mm ID) and subjected to a high-voltage, high-current-density pulse in air for a period of less than 300 microseconds. Single pulses (1.0, 1.5, 2.0 and 2.5 KJ/grampowder) were applied from a capacitor bank (240, 480 or 720 microF) to produce solid core implants with porous surface layers. Implants were evaluated microscopically for core size, neck size, pore size, grain structure, and incorporated oxide film. Hardness was also evaluated. Implants were compared with Ti-6A1-4V commercial powders. Core size increased and pore size decreased with increases in energy and capacitance. The cores were composed of equiaxed grains which were free of oxide at the grain boundary. Porous layers, consisting of particles connected in three dimensions by necks, were free of oxide films at the connecting interfaces. Neck size increased with increases in input energy and capacitance. Hardness readings of the core, necks, and porous particles resulted in readings higher than or similar to control materials. Electrodischarge compaction did not alter the physical characteristics during compaction.

Alloys↗
PubMed1991

Clinical and microbiological effects of a sanguinaria-containing mouthrinse and dentifrice with and without fluoride during 6 months of use.

The purpose of this study was to test the efficacy and safety of sanguinaria-containing regimens with and without fluoride using the American Dental Association guidelines for evaluating chemotherapeutic agents. The study was a 6-month, double-blind, 4-cell, placebo-controlled, parallel investigation involving 120 subjects. Following screening procedures, subjects were randomly assigned to 4 groups. Group 1 received a dentifrice containing 0.075% sanguinaria extract (SaE) and 2.0% zinc chloride (ZnCl2) in a dicalcium phosphate base, plus an oral rinse containing 0.03% SaE and 0.2% ZnCl2. Group 2 received identical products without SaE or ZnCl2. Group 3 received a dentifrice containing 0.8% sodium monofluorophosphate, 0.075% SaE, and 0.05% ZnCl2 in a silica base, plus an oral rinse containing 0.03% SaE and 0.2% ZnCl2. Group 4 products were identical to those of Group 3 but without SaE and ZnCl2. Supragingival plaque and gingival inflammation were scored at 0, 1, 2, 1.5, 3, 4.5, and 6 months; bleeding upon probing was measured at 1, 1.5, 3, and 6 months. Microbiological samples were taken from plaque, tongue, and cheek areas. The active products produced statistically significantly lower scores than the placebo agents for all indices (P less than .0001). Six-month plaque scores were 13.1% lower for Group 1 and 17.4% lower for Group 3 compared to placebo products. When the Plaque Severity Index was applied, the percentage reductions were 33% for Group 1 and 41% for Group 3 compared to placebos. Gingival inflammation scores were 16.7% lower for Group 1 and 18.1% lower for Group 3 at 6 months compared to placebo scores.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Sanguinaria toothpaste and oral rinse regimen clinical efficacy in short- and long-term trials.

Short- and long-term testing of sanguinaria toothpaste and oral rinse used individually have yielded both positive and negative results. This review evaluates the results of a number of clinical trials testing the regimen use of sanguinaria products for periods ranging from 14 days to six months. Review of these trials establishes the clinical efficacy of the two products in combination. The regimen approach produces consistently positive reductions in plaque, gingival inflammation and bleeding parameters for up to six months with no adverse hard tissue effects and only one reversible adverse soft tissue effect observed among the 260 subjects tested. In addition, no adverse microbiological shifts in the normal oral flora were observed.

Alkaloids↗
PubMed1979

Developmental variations of tooth morphology and periodontal disease.

Some developmental variations of tooth morphology may influence the potential for periodontal disease by allowing accumulation of bacterial plaque and calcified deposits. Mechanical plaque control becomes difficult even for the conscientious patient. Periodontal disease may be hastened in these cases. The therapist must be aware of these variations and their significance in the etiology of isolated periodontal lesions. Recognition of these anomalies and early diagnosis may improve the prognosis of the involved tooth.

Dental Cementum↗
PubMed1978

Rationale and methods for crown lengthening.

Surgical crown lengthening should not be attempted when tooth fractures extend into the middle third of the root. Excessive bone reduction on the fractured tooth and necessary blending of osseous contours over adjacent teeth may result in mobility or furcation involvement. In addition, the necessary osseous surgery may create precipitous changes in the bony architecture that will be bridged by soft tissues. This results in increased pocket depth and an unhealthy situation. If the tooth in question has a hopeless prognosis or the osseous surgical procedure would create a poor crown-root ratio, furcation involvement, mobility, or esthetic problems, crown lengthening should be avoided. In cases such as these, extraction may be indicated.

Alveolectomy↗