Longitudinal evaluation of sealing molars with and without incipient dental caries in a public health program.

OBJECTIVES: This study undertook a retrospective evaluation of the effect of sealants on the caries experience of initially sound and incipient permanent first molar pit and fissure surfaces. METHODS: Records of children with complete five-year records were obtained from a school-based dental sealant program in a fluoridated community. Sealants were placed on 677 tooth surfaces in 96 children; 120 tooth surfaces in 17 children who received baseline examinations were not sealed because of lack of caregiver consent. Tooth surfaces were initially diagnosed as being sound or having incipient lesions, and evaluated for caries status after five years. RESULTS: For initially incipient surfaces the five-year decay rate was 10.8 percent (41 of 380 surfaces) for sealed surfaces and 51.8 percent (29 of 56 surfaces) for nonsealed surfaces with an odds ratio of 8.88 (95% CI = 4.56, 17.35). Initially sound surfaces had a decay rate of 8.1 percent (24 of 297 surfaces) for sealed surfaces and 12.5 percent (8 of 64 surfaces) for nonsealed surfaces with an odds ratio of 1.63 (95% CI = 0.63, 4.08). The two odds ratios were significantly different. CONCLUSIONS: Initially sound tooth surfaces were unlikely to become decayed in five years, and did not benefit greatly from the application of sealants. Within the limitations of this study, there were clear efficiencies in sealing incipient, but not sound, surfaces. The targeting of teeth with incipient caries for sealants is therefore recommended.

Twenty-four-month clinical trial of visible-light-activated cavity liner in young permanent teeth.

A clinical study of young permanent teeth for twenty-four months evaluated the use of a new product, VLC-Dycal, as a cavity liner. VLC-Dycal is a light-activated calcium hydroxide cavity liner. After twenty-four months, VLC-Dycal had a 91 percent success rate used as a liner with young permanent teeth. From the fifty-four teeth evaluated at twenty-four months, only five were failures. Failure occurred more frequently with DPC. Of the five teeth that became devital over the twenty-four months, three were DPC. The success rate for DPC was 70 percent. IPC had a success rate of 85 percent. None of the CCR procedures failed in the study. Because of the improved physical properties, VLC-Dycal was evaluated in a clinical trial for biological properties and proved to be a useful cavity liner for young permanent teeth.

Critical evaluation of sampling and gas chromatographic analysis of halocarbons and other organic air pollutants.

Problems connected with the analysis of ultra-trace amounts of halocarbons in air are discussed in terms of trapping procedures, interferences and chromatographic columns. A suitable column for the qualitative and quantitative analysis of C1-C2 halocarbons is described, and examples of applications are given. High-efficiency micropacked columns have been used for the analysis of hydrocarbons in the open atmosphere.

[Evaluation of atmospheric pollution in industrial environment using gas-chromatographic technics]. / Sulla valutazione dell'inquinamento atmosferico in ambienti industriali mediante tecniche gas cromatografiche.

Several analytical techniques for the evaluation of different classes of air pollutants that can be found in working places are described. Particularly an automatic apparatus for monitoring total organic substances less methane, and one, employing specific detection and selective columns for the automatic and continuous determination of light sulfur compounds, are described. An analytical procedure for trapping and selective analysis of organic substances is presented. This includes the description of trapping and enriching devices and of a semi-automatic apparatus for the gaschromatographic analysis of the samples trapped. Some applications of these analytical techniques are described.

Evaluation of organic pollutants in the open air and atmospheres in industrial sites using graphitized carbon black traps and gas chromatographic-mass spectrometric analysis with specific detectors.

A method for evaluating the organic content of the atmosphere, involving the use of personal samplers, is described. A comparison of the performances of Tenax GC and Carbopack B is given in terms of sample recovery. Apparatus including selective columns, specific detectors and combined gas chromatography-mass spectrometry is also described. Practical examples of the analysis of organic air pollutants trapped in the open air and the atmosphere in a chemical plant are discussed. A comparison of the results of complete gas chromatography and of the total hydrocarbon content is also made.

Gas chromatographic column for the viking 1975 molecular analysis experiment.

A gas chromatographic column has been developed for use in the remote analysis of the martian surface. The column, which utilizes a liquid-modified organic adsorbent (Tenax) as the stationary phase, provides efficient transmission and resolution of nanogram quantities of organic materials in the presence of millionfold excesses of water and carbon dioxide.