IADR Abstract Archives
Effect of Surface Layer on Remineralization Rate of Enamel Caries
Objectives: Non-cavitated enamel caries lesions present with two mineral distributions, one with a higher mineral density surface layer while the other without. The objective of this study is to investigate the temporal response of demineralized enamel, with and without surface layer, to different remineralizing agents under pH-cycling conditions
Methods: Eighty human extracted premolars were screened using an Optical Coherence Tomography to identify a 3x3mm2 caries-free region. To induce caries-like lesions, the samples were divided into two groups and incubated in 37°C buffered lactic acid (pH 4.5) for 72 and 48 hours respectively. Each group was divided into four remineralization sub-groups (n=10); i.e., 3M™ Vanish™ 5% Sodium Fluoride White Varnish (F1), experimental fluoride coating (F2), Curodont™ Repair (P) and artificial saliva (S). After lesion formation, each sample received remineralizing treatments and subjected to 12 pH-cycles. Micro-Ct scans were performed at baseline and after 6- and 12- pH cycles. Lesion depth (ld) and △Z were computed. ld was non-parametric while △Z parametric, hence the Friedman’s tests and Repeated Measure ANOVA were used to compare the temporal effect of remineralizing agents for ld and △Z respectively
Results: Median ld of the 72-hrs and 48-hrs lesions were 81.5mm (with a homogenous surface layer) and 65.5mm respectively . In the 72-hrs lesions, F1 and S did not significantly reduce ld whilst F2 and P did after 6 pH-cycles and 12 pH-cycles respectively. For the 48-hrs lesion S did not significantly reduce ld whilst F2 and P did after 6 pH-cycles and F1 after 12 pH-cycles respectively. F1, F2 and P showed similar significant DZ reduction for both types of lesions, i.e. F1 and F2 reduced DZ after 6 pH-cycles while P after 12 pH-cycles.
Conclusions: The surface layer reduced the rate of lesion depth reduction of F1 and P but not of F2.
Methods: Eighty human extracted premolars were screened using an Optical Coherence Tomography to identify a 3x3mm2 caries-free region. To induce caries-like lesions, the samples were divided into two groups and incubated in 37°C buffered lactic acid (pH 4.5) for 72 and 48 hours respectively. Each group was divided into four remineralization sub-groups (n=10); i.e., 3M™ Vanish™ 5% Sodium Fluoride White Varnish (F1), experimental fluoride coating (F2), Curodont™ Repair (P) and artificial saliva (S). After lesion formation, each sample received remineralizing treatments and subjected to 12 pH-cycles. Micro-Ct scans were performed at baseline and after 6- and 12- pH cycles. Lesion depth (ld) and △Z were computed. ld was non-parametric while △Z parametric, hence the Friedman’s tests and Repeated Measure ANOVA were used to compare the temporal effect of remineralizing agents for ld and △Z respectively
Results: Median ld of the 72-hrs and 48-hrs lesions were 81.5mm (with a homogenous surface layer) and 65.5mm respectively . In the 72-hrs lesions, F1 and S did not significantly reduce ld whilst F2 and P did after 6 pH-cycles and 12 pH-cycles respectively. For the 48-hrs lesion S did not significantly reduce ld whilst F2 and P did after 6 pH-cycles and F1 after 12 pH-cycles respectively. F1, F2 and P showed similar significant DZ reduction for both types of lesions, i.e. F1 and F2 reduced DZ after 6 pH-cycles while P after 12 pH-cycles.
Conclusions: The surface layer reduced the rate of lesion depth reduction of F1 and P but not of F2.