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Biomedical subjects

F C Gillespie

Publications and source records attributed to F C Gillespie.

At least 19 recordsLinked to original sources
PubMed1983

An assessment of new dental ultraviolet sources and u.v.-polymerized fissure sealants.

The performance of six dental ultraviolet (u.v.) sources was assessed to establish minimum output requirements and possible u.v. hazards. Exposure criteria for u.v.-cured materials (Nuva-seal P.A., Nuva-cote P.A., Nuva-fil P.A., Lee-seal, u.v.-Dentoseal, Uviobond, Visiobond) were assessed by determining setting time-intensity characteristics, u.v. transmission and microhardness as a function of u.v. intensity and depth. A minimum intensity of 10 mW cm-2 was required for adequate curing and both Nuva-seal P.A. and Nuva-cote P.A. set well in depth with realistic exposures. Total u.v. outputs, average intensities and spatial distributions were assessed for the u.v. sources, most of which were well above minimum requirements. Ultraviolet spectra and maximum permissible exposure measurements indicated that all of the sources were safe in normal use.

Chemical Phenomena↗
PubMed1983

Surface treatment studies aimed at streamlining fissure sealant application.

Three laboratory studies were carried out with the aim of improving or streamlining enamel surface treatment procedures in fissure sealing. In Study 1, the effect of reducing acid etch time from 60 s to 10 s was assessed by SEM and tensile bond strength measurements. Reduction in etch time produced a finer etch pattern, gave a reduced but still high, bond-strength, albeit with slightly poorer long-term adhesion. Study 2 showed that a conventional acid etch treatment could completely remove acquired pellicle, without prior prophylaxis. SEM studies and bond-strength measurements corroborated this view. In Study 3, compressed air and chemical drying agents were compared for drying speed and efficiency. Compressed air gave more rapid, thorough drying, and greater resultant bond strengths.

Acid Etching, Dental↗
PubMed1981

The effect of salivary contamination on fissure sealant--enamel bond strength.

The effect of accidental salivary contamination on the retention of fissure sealants is investigated via in vitro bond tests and scanning electron microscopy. The strength of the bond between sealant and saliva contaminated and washed enamel (168 +/- 14 kg cm-2) is not found to be significantly different from the bond strength to uncontaminated enamel (174 +/- kg cm-2). Unwashed contaminated enamel gives significantly reduced bond strength (68 +/- 11 kg cm-2).

Dental Bonding↗
PubMed1980

Studies on the setting behaviour of sealants using a new acoustic method of determining set.

An acoustic method has been used to compare the setting behaviours of three chemical and three u.v. activated sealants. The setting rates of the u.v. sealants were found to have similar sub-linear dependences on the applied u.v. intensity. However, considerable differences in the rates of set of these materials were noted when the same u.v. intensities were applied. Adjusting the composition of one of the sealants (Alphaseal) increased the penetration of the u.v. radiation, resulting in a ten-fold improvement in the setting rate. Suitable exposure times and the intensities of radiation necessary to satisfactorily set these u.v. sealants are recommended.

Acoustics↗