Biomedical subjects

C M Oliver

Publications and source records attributed to C M Oliver.

5 recordsLinked to original sources

PubMed2001

Correlation between clinical success and apical dye penetration.

AIM: This study was undertaken to examine whether a correlation exists between apical dye penetration and the clinical performance of root fillings. METHODOLOGY: Apical dye penetration into 116 roots of human teeth that had been root-filled at least 6 months prior to extraction was tested in vitro using a vacuum technique and by measuring the length of dye penetration. Endodontic treatment was classified as clinically successful or unsuccessful and results for these groups were compared using analysis of variance and the Student's t-test. Positive and negative controls were used to test the experimental system. RESULTS: All controls performed as expected. Dye penetrated significantly further in unsuccessful cases although the raw data suggested little difference. Overall, dye penetrated 99.5% of the specimens, indicating that the presence of dye in the canal is a poor indicator of whether the technique or material will succeed. However, the extent of dye penetration may be related to the clinical outcome. CONCLUSIONS: Clinically placed root canal fillings do not provide an apical seal that prevents fluid penetration. The outcome of treatment cannot be predicted from the results of apical dye leakage studies.

Coloring Agents↗

PubMed1998

An in vitro study of apical and coronal microleakage of laterally condensed gutta percha with Ketac-Endo and AH-26.

The purpose of this in vitro study was to compare both apical and coronal dye penetration when Ketac-Endo and AH-26 sealers were used with laterally condensed gutta percha. Crowns were removed from 28 teeth and the root canals were biomechanically prepared. The teeth were divided into two groups of 12-teeth each and a control group of 4 teeth. Root canals in the two experimental groups were filled with laterally condensed gutta percha and either Ketac-Endo or AH-26 sealer. The Ketac-Endo group had the coronal 3 mm of gutta percha and sealer removed and the resultant cavity was filled with Ketac-Endo alone. After the sealers had set, the root surfaces were coated with nail varnish except at the apex and at the coronal end. Positive controls had no root fillings and were coated with nail varnish in the same manner while the negative controls were sealed apically and coronally with Cavit prior to sealing the entire external root surface with nail varnish. Specimens were placed in 2% methylene blue dye in a vacuum of 660 mm of mercury for five minutes and then left immersed for a further two days. The roots were vertically sectioned to determine the following mean levels of dye penetration: Ketac-Endo, 1.08 mm apically and 6.29 mm coronally; AH-26, 0.75 mm apically and 6.67 mm coronally. Positive controls had total leakage and negative controls had no leakage. This study demonstrated that the apical and coronal seals obtained with Ketac-Endo and AH-26 were not significantly different although the apical seal obtained with each material was significantly better than the corresponding coronal seal.

Bismuth↗

PubMed1991

Driving and dementia.

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Adaptation, Psychological↗

PubMed1991

Entrapped air and its effects on dye penetration of voids.

This study was conducted to determine the effect of entrapped air on the ability of methylene blue dye to penetrate known and measurable voids. Thirty six capillary tubes were sealed at one end and had standardized voids created within the lumen. Three equal groups of 12 test specimens and 4 controls were subjected to dye penetration by the methods of passive immersion for 7 days, centrifuging at 3,000 rpm for 5 minutes and immersion in a vacuum of 26 mm of mercury for 5 minutes. Measurement of linear dye penetration was made by removing shavings from the sealed end until dye could be observed. Negative controls showed no dye penetration and positive controls showed complete penetration. The vacuum method showed 100% penetration in all cases, while centrifuging had a mean of 91.7 /+ 8.7% penetration and passive immersion had a mean of 20.7 +/- 5.4% penetration. This study demonstrates that passive dye leakage studies are unreliable and very variable. The vacuum method whereby all entrapped air is removed is the most reliable method for dye penetration studies.

Air↗

PubMedDate not supplied

Gentle birth: its safety and its effect on neonatal behavior.

Leboyer describes a method of handling babies at birth designed to decrease initial stimulation and lessen trauma for the infant. Twenty clinic patients were delivered using a modification of this method. They were compared to 17 control patients delivered in the customary manner. Significant differences were noted between the two groups in five of 18 neonate behaviors observed in the delivery room. Among control subjects there was significantly more time spent with hand muscles tense during the first ten minutes after birth; more trembling, shuddering, and blinking during the first 15 minutes after deliver; and more trembling and shuddering overall. Experimental subjects spent significantly more time with hand muscles relaxed during the first ten minutes after birth and more time with open eyes overall. Results of this study indicate the Leboyer method is safe for mother and infant and promotes infant relaxation in the delivery room.

Adolescent↗