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Biomedical subjects

J H Engle

Publications and source records attributed to J H Engle.

10 recordsLinked to original sources
PubMed2000

Clinical evaluation of amalgam bonding in Class I and II restorations.

BACKGROUND: Many dental practitioners are bonding amalgam to tooth structure. Although in vitro studies support this procedure, its efficacy has not been adequately confirmed in the clinical environment. METHODS: The authors placed traditional Class I and Class II bonded and unbonded amalgam restorations in 76 patients. Panavia 21 (J. Morita USA Inc.) was the bonding agent selected, and Aristaloy CR (Englehard Dental) and Tytin (Kerr Corp.) were the amalgam alloys used. Postoperative sensitivity and marginal fracture were evaluated at yearly intervals, for up to three years of clinical service. RESULTS: At the patients' appointment for polishing one to two weeks after restoration placement, and at each yearly recall appointment, the authors found no significant difference in postoperative sensitivity between bonded and unbonded restorations for either amalgam alloy (chi 2 analysis, alpha = .05). In addition, there was no significant difference between bonded and unbonded restorations for either amalgam alloy with respect to marginal fracture (analysis of variance and Tukey's contrasts at alpha = .05). Moreover, no cusp fractures were observed for either bonded or unbonded restorations. CONCLUSIONS: After three years of clinical service, amalgam bonding for traditional Class I and Class II restorations had no effect on postoperative sensitivity or marginal integrity. CLINICAL IMPLICATIONS: The merit of using adhesive bonding agents for traditional Class I and Class II amalgam restorations was not demonstrated in this three-year clinical study.

Adolescent↗
PubMed1996

One-year clinical evaluation of bonded amalgam restorations.

Using one selected amalgam bonding agent, the authors evaluated bonded and unbonded restorations in clinical service. Based on postoperative sensitivity one to two weeks after placement and marginal fracture at one year, no difference was found between the bonded and unbonded restorations. Furthermore, some technical difficulties were experienced with use of the bonding agent.

Adhesives↗
PubMed1995

Oxygenator evaluation: Maxima 1380 versus Maxima Plus.

Continual improvement of oxygenators has been important in the growing demands of patient safety and support during cardiopulmonary bypass. The purpose of this study was to compare the Maxima 1380 oxygenator to the upgraded Maxima Plus oxygenator. Thirty-two adult patients were randomized to either the 1380 group or the Plus group. Information was recorded on the patients' weight, age, body surface area, esophageal temperature, arterial temperature, venous oxygen saturation, arterial pO2, arterial pCO2, blood flow, hematocrit, gas sweep, and FiO2. No significant difference was found between the two groups' mean weight, body surface area, arterial pO2 arterial pCO2, age, esophageal temperature, arterial temperature, venous oxygen saturation, and blood flow (p > 0.05). The Plus group demonstrated significantly lower mean gas sweep rates and FiO2 settings than the 1380 group. FiO2 of the 1380 was dependent on age, body surface area, blood flow, and esophageal temperature (r = 0.89, p < 0.001). FiO2 of the Plus was correlated with weight, esophageal temperature, arterial temperature, and arterial pO2 (r = 0.93, p < 0.001). Gas sweep rate of the 1380 was dependent on age, weight, esophageal temperature, blood flow, arterial temperature, and arterial pCO2 (r = 0.84, p < 0.001). The gas sweep rate of the Plus was dependent on weight and esophageal temperature (r = 0.55, p < 0.001). Based on these analyses, the new Maxima Plus oxygenator is more efficient in oxygen and carbon dioxide transport than the Maxima 1380.

Adult↗
PubMed1994

Reduction in operatory mercury levels after contamination or amalgam removal.

The threshold limit value (TLV) for occupational exposure to mercury can be exceeded in the dental operatory after a contamination event or during certain dental procedures. The objective of this study was to determine the time required for the mercury vapor levels to return to baseline in both non-ventilated and ventilated operatories after they had been contaminated with mercury to the TLV of 0.050 mg/m3; and to evaluate the efficiency of an activated charcoal filtering device for removing mercury vapor. The results showed that even in a poorly ventilated operatory, the mercury vapor level returned to background within 20-30 minutes after a contamination, and within 10-20 minutes when the operatory was ventilated. The filtering device reduced the level of mercury vapor by approximately 25% during a continuous contamination event, but did not clear the operatory faster than normal settling after a limited source contamination. The filter caused a significant reduction in mercury in the breathing zones of the patient and dentist during and after amalgam removal, but did not eliminate the exposure. This study demonstrated the difficulty in contaminating an operatory with mercury vapor and confirmed the limited time mercury remains airborne, presumably due to its density and affinity for surfaces.

Air Pollution, Indoor↗
PubMed1993

The interval nature of an ordinal scale for measuring the marginal fracture of amalgam.

The clinical performance of amalgam alloys over time has been assessed by measuring the extent of marginal fracture of restorations made from these alloys. Scales of photographs of restorations exhibiting varying degrees of marginal fracture have been used to make these assessments. The purpose of this study was to determine the relationship between the ordinal scale numbers of five photographs composing a commonly used scale (Mahler and Marantz, 1979) and the average width in micrometers of marginal fracture of the restorations in the photographs of this scale. In addition, a comparison was made between parametric and non-parametric statistical methods when applied to marginal fracture data. The results showed that four of the five photographs of this scale demonstrated a significant linear regression with marginal fracture width (R2 = 0.997; p = 0.002). The last photograph of the scale, which proved to be an outlier, was not used in the regression and was accommodated by an extrapolation procedure. Using previously gathered clinical data on the marginal fracture behavior of five amalgam alloys, the use of parametric statistical procedures (ANOVA and Scheffé's multiple comparison test) proved to be more discriminatory than the use of nonparametric procedures (Kruskal-Wallis and Dunn's Multiple comparison test) when tested at the same overall confidence level. Thus, having a photographic scale of an interval nature removes any doubt about using the more powerful technique of parametric statistics to evaluate the marginal fracture behavior of dental amalgams.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Quantitation of total mercury vapor released during dental procedures.

An in vitro method is described in which measurements were made of the total amount of mercury vapor released from three types of amalgam during routine dental procedures. It was found that the greatest amount of mercury was released during dry polishing of one amalgam (44 micrograms). Removal of amalgam from a Class I cavity under water spray and high volume evacuation also generated large amounts of mercury as expected (15-20 micrograms). However, under the more clinically relevant conditions of extending evacuation for one minute to remove residual amalgam and mercury after cutting, this value was reduced by approximately 90%. The total amount of mercury generated during placement (6-8 micrograms), wet polishing (2-4 micrograms) and trituration (1-2 micrograms) were also measured. The study showed that dental procedures associated with amalgam do potentially expose the patient and operator to mercury vapor. However, the total amount of mercury released during any procedure was far below the total exposure level calculated from the daily threshold limits established by regulatory agencies for occupational exposure.

Air Pollutants, Occupational↗
PubMed1990

Effect of Pd on the clinical performance of amalgam.

The purpose of this study was to determine the effect of a small amount of Pd on the clinical performance of a high-copper spherical-particle dental amalgam. Two identical alloys, with and without 0.5% Pd, were investigated. The marginal fracture, surface texture, and surface luster of 193 clinical restorations were evaluated at one year, those of 182 at two years, and those of 144 at three years of service. In vitro corrosion tests of anodic polarization and constant potential coulometry were also conducted. Over the three-year period, the results showed no differences in marginal fracture or surface texture between the two alloys. However, the alloy with Pd showed a significant superiority in surface luster over this time period. Both corrosion tests showed less electrochemical activity on the part of the alloy containing Pd.

Adolescent↗
PubMed1986

Standardizing evaluations of the clinical marginal fracture of amalgam.

In this study, we investigated both inter-examiner and intra-examiner differences in the evaluation of the marginal fracture characteristics of dental amalgam restorations. Evaluations were made by matching intra-oral photographs of the occlusal surfaces of clinical restorations to a reference set of clinical photographs illustrating increasing amounts of marginal fracture. Four amalgam alloys and five examiners provided the data base. Differences in marginal fracture indices were found among examiners and between evaluation times for the same examiners. However, these differences were reduced significantly after application of a standardization procedure.

Dental Alloys↗