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Biomedical subjects

G P Willis

Publications and source records attributed to G P Willis.

8 recordsLinked to original sources
PubMed1999

Preventing dental calculus formation in lemurs (Lemur catta, Eulemur fulvus collaris) and baboons (Papio cynocephalus).

The prevention of calculus accumulation in exotic animals is a relatively unexplored topic. A 6-mo study in ring-tailed lemurs (Lemur catta) and collared lemurs (Eulemur fulvus collaris) and two studies in baboons (Papio cynocephalus) (7.5 wks and 6.5 mo) tested the benefits of a primate diet coated with 0.6% sodium hexametaphosphate (HMP) in controlling calculus in these species using a sequential crossover design. The control regimen was an identical, but non-HMP-coated, dry primate chow. At study initiation, the primates were given a thorough dental prophylaxis and provided with the control diet or experimental diet. At the conclusion of the test period, the animals were anesthetized and examined for clinical calculus independently by two examiners. The animals were then given another dental prophylaxis, provided the alternate ration, and the foregoing procedures were repeated. When the animals were provided the HMP-coated diet, significant reductions in calculus formation of 48-62% were observed in the lemurs and the baboons. No clinically significant changes were observed in body weights or in blood chemistry values as a result of ingestion of the HMP-coated regimen.

Animal Feed↗
PubMed1994

Pulp reactions to light-cured glass ionomer cements.

This study compared the pulp responses to two light-cured glass ionomer liners with a chemically set glass ionomer lining cement and zinc oxide-eugenol. Deep Class V cavities were prepared at high-speed with carbide burs under a water coolant in 96 teeth of three young adult beagle dogs. The smear layer was left intact according to the manufacturers' recommendations. The cavities in each quadrant were lined with either Vitrebond light-cured glass ionomer liner, X-R Ionomer light-cured liner, GC lining cement or ZOE which served as a control. All cavities were restored with Silux Plus resin composite. The ZOE liner was covered with a varnish prior to the resin composite placement. The animals were terminated at 1, 4 and 12 weeks. Jaws were excised, fixed in 10% formalin and decalcified in 5% formic acid. Teeth were sectioned at 7 microns, and stained with hematoxylin and eosin. Selected slides were stained with the Brown and Hopps method for histologic demonstration of bacteria. The microscopic findings indicated that pulpal reactions to the two light-cured glass ionomer liners were minimal and comparable to those elicited by the chemically-cured glass ionomer lining cement and ZOE. Bacteria were observed in nine specimens but only one of these revealed a moderate pulp reaction.

Animals↗
PubMedDate not supplied

Orthodontic decalcification management with microabrasion.

Patient home care during orthodontic treatment is often less than ideal. For those patients who routinely let plaque accumulate around orthodontic appliances, there can be white or stained areas of decalcification around the bonded appliances. Management of this esthetic problem can be accomplished in several ways depending on the severity of the defect. This paper describes the very conservative technique of microabrasion which works well in removing superficial markings caused by decalcification. In a sample of 98 decalcified teeth from 20 patients with orthodontic decalcifications and various other unesthetic stains, microabrasion removed most or all of the disfiguring marks on 78.5 percent of the teeth evaluated. At least some improvement was noted 96.9 percent of the time. These results were statistically significant (P > .01). It seems appropriate to employ this technique prior to initiating more aggressive cosmetic dentistry such as resin bonding, Class V restorations, or labial veneers.

Dental Enamel↗