Different bacterial models forin vitroinduction of non-cavitated enamel caries-like lesions: Microhardness and polarized light miscroscopy analyses

Abstract

The aim of this study was to compare different bacterial models for in vitro induction of non‐cavitated enamel caries‐like lesions by microhardness and polarized light microscopy analyses. One hundred blocks of bovine enamel were randomly divided into four groups (n = 25) according to the bacterial model for caries induction: (A) Streptococcus mutans, (B) S. mutans and Lactobacillus acidophilus, (C) S. mutans and L. casei, and (D) S. mutans, L. acidophilus, and L. casei. Within each group, the blocks were randomly divided into five subgroups according to the duration of the period of caries induction (4–20 days). The enamel blocks were immersed in cariogenic solution containing the microorganisms, which was changed every 48 h. Groups C and D presented lower surface hardness values (SMH) and higher area of hardness loss (ΔS) after the cariogenic challenge than groups A and B (P < 0.05). As regards lesion depth, under polarized light microscopy, group A presented significantly lower values, and groups C and D the highest values. Group B showed a higher value than group A (P < 0.05). Groups A and B exhibited subsurface caries lesions after all treatment durations, while groups C and D presented erosion‐type lesions with surface softening. The model using S. mutans, whether or not it was associated with L. acidophilus, was less aggressive and may be used for the induction of non‐cavitated enamel caries‐like lesions. The optimal period for inducing caries‐like lesions was 8 days. Microsc. Res. Tech. 78:444–451, 2015. © 2015 Wiley Periodicals, Inc.

Effectiveness of Fluorescence-based Methods in Monitoring Progression of Noncavitated Caries-like Lesions on Smooth Surfaces

“…3 It was verified that the in vitro methodology used was capable of forming caries-like lesions in enamel using a bacterial model composed of S. mutans and L. acidophilus, simulating the process of dental caries. 24,29 The bacterial model offers the opportunity to evaluate the variability and exchangeability of the species involved in the carious process and factors such as lesion site or availability of fermentable carbohydrates. [30][31][32] To evaluate the effectiveness of fluorescence-based methods for monitoring enamel caries lesions, an in vitro model using bacterial films is likely to be more realistic than chemical systems since the devices have the potential to identify bacterial metabolites such as porphyrins (fluorophores and other chromo-phores) produced by cariogenic bacteria.…”

“…Other studies on enamel demineralization have also used CSMH profiling for validation and evaluated the artificial caries lesion depth in a polarized light microscope. 6,16,24,42 It is important to point out that researchers have used a considerable number of analytical techniques to quantify changes in the mineral content of enamel during caries lesion formation. 43 Transverse microradiography (TMR) provides a quantitative measure of the mineral content, lesion depth, and attributes of the surface layer in enamel lesions.…”

“…24 The experimental period for initial assessment of caries lesions was determined at eight days (phase II) and the second assessment after a further eight days (phase III).…”

Vertical scanning interferometry: A new method to quantify re-/de-mineralization dynamics of dental enamel

“…Dietary acids and bases can induce surface erosion, as can many combinations of bacteria in dental plaque. For example, while Streptococcus mutans alone, and the combination of S. mutans and Lactobacillus acidophilus tend to induce subsurface lesions, the combination of S. mutans and L. casei, or S. mutans, L. acidophilus, and L. casei, has been shown to produce surface cavitations [51]. Nevertheless, the application of VSi for analysis of surface erosion is relevant, independent of the cause/origin of such erosion.…”

Desenvolvimento de lesões de cárie em dentina em um modelo de biofilme simplificado in vitro: um estudo piloto

“…Modelos laboratoriais de biofilmes vêm sendo desenvolvidos com a finalidade de simular in vitro o ambiente bucal [6][7][8][9][10] , devido à dificuldade de investigação do biofilme in vivo, limitação de 41/44 quantidade amostral, complexidade do ambiente bucal e a questões éticas relacionadas com estudos envolvendo cárie dentária em seres humanos 8,10 . E embora estudos in situ possam ser utilizados como uma ponte entre estudos in vitro e in vivo, através do uso de dispositivos intraorais que viabilizam a remoção das amostras em períodos de tempo predeterminados, o acesso às características do biofilme e perfil de desmineralização também possuem limitações como custos, tempo e dependência da colaboração do paciente.…”