[Caries prevalence among schoolchildren in Zoetermeer. A study performed by primary health doctors]. / Cariësprevalentie onder Zoetermeerse schoolkinderen. Een onderzoek uitgevoerd door JGZ-artsen.

In a study performed by primary health doctors among 10- and 11-year-olds in Zoetermeer (the Netherlands), 72% of the children were found to possess four healthy permanent first molars. The examination was exclusively based on visual inspection by means of mouth mirrors.

Preventive measures and caries progression: an in vitro study on fissures and smooth surfaces of human molars.

The aim of this study was to compare pit-and fissure sealants with fluoride treatments in their effectiveness to inhibit or reduce the progression of enamel lesions, particularly in the fissure region. The effects of fissure probing as used in diagnosis were compared with in the same protocol. Using a combination of image analysis of X-ray pictures of full crowns and a light microscopic evaluation of cross-sections provided information on the three dimensional spread of enamel demineralization. Pit-and-fissure sealants were superior in protecting enamel against progression of demineralization, as long as the walls of the fissures were well covered. The protection against demineralization offered by fluoride was mainly restricted to the smooth enamel surfaces; in fissures no protection could be measured. Surface defects of the enamel caused by probing or abrasion aided the progress of the lesion.

Mineral loss during etching of enamel lesions.

This study was aimed at determining the amount of mineral removed from incipient enamel lesions during acid etching. The rationale being that fissures which are scheduled for sealing will often have undetected demineralized regions. Lesions were formed in bovine enamel specimens using either an acidified gelatine gel or a lactate buffer containing methane hydroxy diphosphonate. Different parts of each lesion were acid-etched either for a 1- or for a 2-min period in 36% H3PO4 or served as control. Mineral content profiles were recorded on thin sections using computerized microradiography to determine the mineral loss resulting from acid etching. The results show that during etching a layer at the outer surface is removed completely. The thickness of this layer was greater for lesions when compared with sound enamel and depended on the lesion characteristics (porosity and fluoride content). The amount of mineral removed from the deeper layers of the lesion was very small; and in the innermost part of the lesions the mineral profiles of the control and acid-etched areas coincide. These observations indicate that the effect of etching is essentially restricted to a thin outer layer, irrespective of the porosity of the underlying tissue. Although the thickness of the etched-off layer was different between the two types of lesions, these findings were made for both types studied. In practical terms this implies that etching of enamel lesions does not cause an excessive mineral loss throughout the lesion.

The effect of dental probing on subsequent enamel demineralization.

By using an explorer on demineralized fissures, an entrance may be created through which cariogenic micro-organisms and their metabolic products can directly penetrate into the softened subsurface. The effect of probing on the rate of formation and growth of lesions was quantified in vitro.