An in situ Enamel Section Model for Assessment of Enamel Re/Demineralization Potential

Abstract

An enamel-section-carrying intra-oral appliance to predict the results of double-blind anti-caries studies has been developed. Initial validation was against the F concentration effect attained in a clinical trial where three sodium monofluorophosphate (SMFP) dentifrices were used. Original appliance-based work showed significant differences in remineralization between non-F and F dentifrices, but not between different F dentifrices. However, it was shown later that acidified gel-prepared lesions were not as responsive as solution-prepared lesions to de- and remineralizing processes, and lesion remineralization rates were found to be dependent on initial lesion size. An in situ cross-over study was then repeated with use of acid-solution-created lesions, and seven volunteers completed the project. Each brushed twice daily x 2 min with either 0, 1000, or 2500 ppm F, as SMFP dentifrice. After a two-week wash-out, subjects wore the appliances for four weeks. Enamel mineral content was assessed at 0, two, and four weeks via microradiography/microdensitometry, and a statistically significant dose-response was obtained between non-F and F as well as between 1000 and 2500 ppm F pastes, i.e., as per the three-year clinical trial data. Hence, the model's suitability for pre-clinical screening was confirmed. It has also been used in caries microbiological studies, in root caries investigations, and currently in chewing gum cariogenicity experiments.

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.…”

Influence of Nail Varnish on the Remineralization of Enamel Single Sections Assessed by Microradiography and Confocal Laser Scanning Microscopy

“…Several authors [von Bartheld, 1980;Featherstone and Silverstone, 1982;Harvey et al, 1982;ten Cate and Exterkate, 1986;Mellberg et al, 1986;Creanor et al, 1986;Wefel et al, 1987;Strang et al, 1987;1988;Stephen et al, 1992;Lammers et al, 1990;Exterkate et al, 1993;Damato and Stephen, 1994] employed various varnishes and adhesives to prepare 'windows' and/or to cover cut surfaces. To 398 Caries Res 1998;32:393-400 Iijima/Takagi/Duschner/Ruben/Arends the authors' knowledge no previous work on the importance of NV penetration has been reported.…”

“…Single-section techniques have been used to investigate demineralization and remineralization of enamel and dentine in vitro [Featherstone and Silverstone, 1982;Harvey et al, 1982;ten Cate and Exterkate, 1986;Strang et al, 1988;Lammers et al, 1990;Exterkate et al, 1993;Inaba et al, 1995] as well as in situ [Creanor et al, 1986;Mellberg et al, 1986Mellberg et al, , 1992Mellberg, 1992;Wefel et al, 1987;Wefel, 1990;Strang et al, 1987;Stephen et al, 1992;Damato and Stephen, 1994]. Two types of single-section techniques are currently used to create lesions in enamel or dentine.…”

“…Another aspect when thin sections are employed is the coating or sealing of exposed section sides. Nail varnish (NV) is most widely used to protect cut surfaces of thin sections in a demineralization or remineralization experiment [Creanor et al, 1986;ten Cate and Exterkate, 1986;Strang et al, 1988;Wefel et al, 1987;Stephen et al, 1992;Damato and Stephen, 1994].…”

Demonstration of a Fluoride Dose Response with an In situ Single-Section Dental Caries Model

“…The cut surfaces o f the sec tions were covered with an acid-resistant nail varnish (Max Factor, En gland), leaving exposed the outer enamel containing the artificial car ies. Sections were dried overnight and mounted in recessed troughs of a lower lingual appliance with two sections on each side o f the ap pliance, as described by Stephen et al [1992], …”