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Biomedical subjects

R B Mayhew

Publications and source records attributed to R B Mayhew.

At least 19 recordsLinked to original sources
PubMed1992

Duration of anesthesia using the periodontal ligament injection: a comparison of bupivacaine to lidocaine.

The purpose of this study was to compare the duration of pulpal anesthesia obtained with 0.5% bupivacaine HCl with 1:200,000 epinephrine to 2% lidocaine HCl with 1:100,000 epinephrine, using the periodontal ligament (PDL) injection. Twenty-four subjects received bilateral PDL injections using mandibular premolar teeth and a double-blind research design. Anesthesia was defined as no response to maximum output of an electric pulp tester. An overall success rate of 35.4% was achieved. Duration of anesthesia obtained with bupivacaine HCl ranged from 4 minutes 59 seconds to 16 minutes 37 seconds with a mean duration of 10 minutes 24 seconds. Excluding one instance in which the duration was three orders of magnitude beyond the norm, duration of anesthesia obtained with lidocaine HCl ranged from 1 minute 43 seconds to 16 minutes 16 seconds with a mean duration of 7 minutes 10 seconds. Postoperatively, all experimental teeth tested vital with no clinically apparent pulpal or periodontal damage. Some postoperative discomfort was experienced at 16.6% of the injection sites.

Adult↗
PubMed1992

Safe storage times for sterile instrument packs.

Military health care facilities are required to place expiration dates on sterile instrument packs. There are few scientific guidelines for determining these dates. This article reports the findings of two studies conducted at Wilford Hall USAF Medical Center, which investigated the potential shelf-life of three packaging materials for sterile instruments. The results of the studies indicate that sterility is maintained for at least 1 year with all three materials. The maximum storage times allowed for sterile instruments at most military facilities appear to be overly restrictive.

Culture Media↗
PubMed1991

Evaluation of the shelf life of sterile instrument packs.

No published studies have specifically addressed the shelf life of sterile packaging materials commonly used in dentistry. This study examined the effect of time on the sterile integrity: paper envelopes, peel pouches, and nylon sleeves. Seven thousand two hundred sample packs, each containing three glass rods, were prepared and steam sterilized. After sterilization, half the packs (control packs) were immediately opened and the contents were analyzed for bacterial contamination. The other half (test packs) were randomly sorted and stored in dental treatment operatories. At monthly intervals for 12 months, 100 packs of each type were similarly opened and analyzed. The contamination rates between the control packs were not significantly different from one another. Differences in contamination rates between control packs and test packs for both the paper envelopes (0.4% and 0.7%) and the peel pouches (0.2% and 0.2%) were also insignificant. However, a significant difference (p less than 0.01) between control and test packs (0.3% and 1.5%) was found for the nylon sleeves. This increase was not time related and was attributed to difficulty in removing the glass rods from the nylon packs in a sterile manner. The most important finding was the absence of a trend toward an increased rate of contamination over time for any pack type. This indicates that when these materials are placed in covered storage in dental operatories, a 12-month storage period is not detrimental to their sterile integrity.

Chi-Square Distribution↗
PubMed1990

Incidence of hepatitis B exposure among USAF dental laboratory technicians.

The purpose of this study was to survey, serologically, the exposure history of USAF dental laboratory technicians to hepatitis B virus (HBV), and to compare the incidence to that found in the general military population. Blood samples from 145 technicians, with an average age of 26.9 (S.D. = 6.9) in four locations in the USA and Europe, were tested for the presence of HBV core antibody using a standard enzyme immunoassay (EIA) procedure. These results were compared against 397 military members in non-medical fields of equivalent age and rank. The binomially distributed data was converted to a z distribution and a statistically significant difference was found in a comparison of the probability of detecting anti-HBc in each population (P = 0.034) where the incidence among the technicians was 2.7% and the military population 0.76%. Use of a "barrier system" in the laboratory, and vaccinations, could prevent any increase in this incidence from an occupational source.

Adult↗
PubMed1987

Evaluation of the barrier system, an infection control system for the dental laboratory.

An experimental system of laboratory infection control was tested, using 76 dentures from 40 volunteer patients. The dentures were cleansed on entering and again on leaving the laboratory. To evaluate the effectiveness of disinfection, the dentures were cultured as they were received from the patient, after the first cleansing, after polishing, and after the second cleansing. The disinfection of the prostheses involved scrubbing them with Hibiclens skin cleanser, rinsing, disinfection in one of three disinfectants (1:16 Sporicidin solution, full-strength Sporicidin solution, and 5.25% sodium hypochlorite [undiluted Clorox]), and finally rinsing. Full-strength Sporicidin solution was significantly more effective than diluted Sporicidin solution, but no statistically significant difference was found between full-strength Sporicidin solution and sodium hypochlorite, or between sodium hypochlorite and 1:16 Sporicidin solution. All three solutions were effective in reducing or eliminating culturable aerobic bacteria.

Communicable Disease Control↗
PubMed1986

The influence of contamination on the bond strength of an etched resin-bonded retainer.

This investigation examines the influence of potential sources of contamination on the resin bond strength of a base metal alloy. Sixty specimens were cast in a base metal alloy and etched. Composite resin cylinders were bonded to six groups of ten specimens each and tested for shear bond strength using a testing machine at a strain rate of .5 mm/min. Five of the test groups received a different set of treatments, and one of the test groups was a control group. An analysis of variance disclosed no significant differences in bond strengths among any of the test groups at a level of P less than .05.

Acid Etching, Dental↗
PubMed1986

A clinical comparison of three anterior restorative resins at 3 years.

An in vivo comparison was made of three different types of restorative resins: a conventional composite resin, a chemically cured microfilled resin, and a small-particle, glass-filled, visible light-cured composite resin. Twenty-eight sets of three restorations were placed 20 patients and examined using the Ryge rating system. All resins performed well and were not significantly different from one another at 1 year. After 3 years, all materials were considered satisfactory, but the conventional composite resins had significantly more surface roughness than did the other resins. Each of the resin materials also declined in color match after 3 years.

Acrylic Resins↗
PubMed1986

Reduction of microbial contamination in dental units with povidone-iodine 10%.

Ten dental units were surveyed for microbial contamination of the waterlines. All units were found to be colonized with bacteria and fungi at levels ranging from 9.0 X 10(4) to 4.1 X 10(5) CFU/mL. Undiluted povidone-iodine 10%, loaded in five experimental units for 12 hours prevented recovery of microorganisms for 3 to 14 days when used in combination with sterile water reservoirs. Use of sterile water reservoirs alone did not effectively reduce levels of microbial contamination in five control dental units.

Bacteria↗
PubMed1986

Depression. Recognition and control.

Depression, as a primary or secondary illness, is a potentially devastating disorder that can significantly affect one's quality of life and, in its worst form, lead to suicide. Stress is an inherent aspect in the practice of dentistry and, allowed to grow unchecked, can lead to mental anguish and depression. However, effective coping strategies can neutralize the effect of stress and make the delivery of dental care an enjoyable experience. The majority of dentists have developed effective means of coping with professional stresses in a fashion that is consistent with other professionals and white-collar workers. Although dentists may become depressed, they do not seem to be drinking, divorcing, or committing suicide in numbers greater than the nonprofessional population. If dentists can learn to deal with their unique stresses, through either undergraduate or continuing dental education, then depression among practitioners could be noticeably reduced.

Adult↗
PubMed1985

Bond strengths of three resin systems used with brackets and embedded wire attachments.

Orthodontic wire bonded directly to teeth with a resin adhesive system has been used to establish anchor units for procedures in orthodontics as well as for splinting teeth in other disciplines. This procedure can save the cost and time of placing a bracket. In addition, several different resin systems have been used for this procedure as well as for placing brackets. The purpose of this study was to determine the strength of three adhesive systems used to bond orthodontic wires directly to teeth and to compare these values with those found for directly bonded orthodontic brackets. Equal sample sizes of brackets or wires were attached to 240 human teeth with either Concise, Miradept, or Endur in a standardized area of etched enamel. Shear and tensile strengths were measured at 30 minutes and at 48 hours. At 30 minutes brackets were significantly stronger than embedded wires, and Concise was significantly stronger than either of the other resins. However, all significant differences between any of the three resin systems using either bonded brackets or wires disappeared at 48 hours. Whether or not this initial strength difference is clinically significant remains speculative.

Acrylic Resins↗
PubMed1966

Isolation and characterization of Hydrogenomonas facilis bacteriophages under heterotrophic growth conditions.

Pootjes, Christine F. (The Pennsylvania State University, University Park), R. B. Mayhew, and B. D. Korant. Isolation and characterization of Hydrogenomonas facilis bacteriophages under heterotrophic growth conditions. J. Bacteriol. 92:1787-1791. 1966.-We have isolated five strains of bacteriophage specific for Hydrogenomonas facilis. The host range of the phage is limited to H. facilis. Morphologically, the phage particles consist of a head 580 A in diameter and a short tail 200 A in length. The particles share a common surface antigen, and all contain deoxyribonucleic acid. The five strains differ from each other in growth characteristics, heat stability, and neutralizing antigens.

Antigens↗