Findings from an in situ Thin-section Sandwich Model for Evaluating Cariogenic and Anti-cariogenic Activity

Abstract

This report summarizes the findings from eight individual remineralization studies that used the thin-section sandwich model. This model uses thin sections of human enamel (or dentin) containing caries-like lesions sandwiched between sheets of thin plastic which are then implanted into the buccal surfaces of molars in removable partial mandibular dentures. Toothbrushing with a sodium fluoride-positive control dentifrice for two-week periods always produced positive remineralization of the lesions, and similar use of a placebo always produced mean mineral loss. In most studies, the difference was significant at p less than 0.01. However, variation among specimens placed within an individual mouth were often large and even included cases where one lesion gained mineral while a closely adjacent lesion lost mineral. Similarly, mean mineral changes produced by an individual subject were not consistent from study to study and ranged from net demineralization in one study to net remineralization in another study. Nevertheless, mean mineral changes from all eight studies showed that all subjects produced more remineralization than demineralization when using a sodium fluoride-positive control dentifrice. Data are presented showing remineralization of thin-section lesions from a number of other fluoride and non-fluoride dentifrices and mouthrinses and showing that a product with reduced anti-caries activity (as measured by several tests) also resulted in reduced remineralization by the thin-section model.

Anticaries Potential of a Sodium Monofluorophosphate Dentifrice Containing Calcium Sodium Phosphosilicate: Exploratory in situ Randomized Trial

“…Assuming that the longer intraoral exposure of the subsurface lesions was not crucial and that SMH measurements correspond to the mineral content [Lippert and Lynch, 2014] and are therefore comparable to the TMR observations on subsurface lesions, it is striking that surface-softened lesions remineralized whereas subsurface lesions demineralized further. These observations are, at least in principle, in disagreement with the present knowledge about the importance of baseline mineral loss of lesions in subsequent in situ de-and remineralization [Strang et al, 1987;Mellberg et al, 1992]. One explanation for the present findings may lie in the fact that lesions were not comparable in that the surface-softened lesions exhibited a different mineral distribution than the subsurface lesions [for comparison, see Lippert and Lynch, 2014;Lippert et al, 2013].…”

In situ Acid Resistance of in vivo Formed White Spot Lesions

“…Therefore, to interpret the results correctly we should not forget the question regarding how representative of the general population such a small number of participants can be. The advantages of intraoral models and single sections were well reviewed by Manning and Edgar [1992] and Mellberg et al [1992], Stephen et al [1992], and Wefel and Jensen [1992], respectively. The in situ appliance described in this text may be a suitable model for studying demineralization rather than remineralization.…”

In vitro Remineralization of in vivo and in vitro Formed Enamel Lesions

“…The technique used in this study shows several advantages for single section use in de-or remineralization experiments [Mellberg et al, 1992;Wefel and Jensen, 1992]. Although there are limited disadvantages as well, [ten Cate and Exterkate, 1986], one of the most important advantages is that it makes quantitative microradiographical evaluation possible repeatedly.…”