Ability of different restorative materials to preventin situsecondary caries: analysis by polarized light-microscopy and energy-dispersive X-ray

Iron Level in Pregnant Rats is Associated with Caries Susceptibility in Offsprings

Iron deficiency anemia (IDA) is a prevalent issue in pregnant women and children. However, the causal relationship between IDA in pregnancy and caries susceptivity in offspring remains unclear. This study aimed to explore the role of iron level during pregnancy on caries susceptivity of offsprings. Here, low-iron (LI) and high-iron (HI) models were established in maternal rats, and iron-related characteristics were examined in maternal rats and their offsprings. After induction of caries in rat offsprings, the carious lesions were evaluated by the Keyes scores, and microstructural damages in molars were observed by scanning electron microscopy. The results showed that LI in maternal rats induced IDA in rat offsprings, and HI only increased serum ferritin in offsprings. LI and HI in maternal rats had no effect on the morphological structure of salivary glands in rat offsprings. After inducing caries, rat offsprings in the LI group exhibited significant increase in enamel lesions at the smooth surface, and on enamel, slight dentinal, and moderate dentinal lesions at the sulcal surface. Only enamel lesions at the sulcal surface were significantly weakened in the HI group. Additionally, visible enamel damages were observed in the LI group. To sum up, iron deficiency during pregnancy enhances caries susceptibility in rat offsprings.

The Influence of Beverages on Resin Composites: An In Vitro Study

Dental composites, through their structural diversity, represent the biomaterials frequently used in dental reconstructive therapy. The aim of our study was to observe the influence of different beverage environment conditions on seven types of obturation dental materials with different compositions. Our research focused on the surface modification analysis of the materials after the immersion in the different beverages; in this regard, we used the EDAX technique correlated with the energy-dispersive X-ray fluorescence (XRF). The pH of the drinks and that of the simulated saliva solution were determined by the titrimetric method, a sodium hydroxide solution 0.1 mol/dm3 was prepared and used for the titration. An amount of 5 mL of each analyzed solution was added to 15 mL of distilled water to obtain a dilution, to which 3 drops of phenolphthalein (as a color indicator-Phenolphthalein, 3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone, C20H14O4 Mw: 318.32, purchased from Merck) were added for each analysis. For each solution, the experiment was repeated three times in order to obtain accurate results. The results of our study materialized into a real plea for modifying the patients' behavior in terms of diet and preferences for acidic drinks, so that their quality-of-life valence can be improved by keeping the composite materials in a long-term unalterable state on the one hand; on the other hand, systemic damage can be prevented as well.

Recurrent caries models to assess dental restorations: A scoping review

OBJECTIVES

To review the literature on recurrent caries models used to evaluate restorative materials, compare reported methodology and parameters, and devise specific recommendations to be considered in future investigations.

DATA

The following were extracted: study design, sample characteristics, source of teeth, name of restorations compared including controls, recurrent caries model type, type of demineralizing and remineralizing solutions, type of biofilm used, methods to detect recurrent caries.

SOURCES

Literature searches were performed in OVID Medline, EMBASE, SCOPUS, and Cochrane Library.

STUDY SELECTION

For a study to be included, it had to examine dental materials for tooth restoration purposes only with a valid control group and evaluate restorative dental materials regardless of the form of the teeth caries model used or nature of the tooth structure used. A total of 91 studies were included. Most of the studies presented were in vitro. Human teeth were the main source of specimens utilized. Around 88% of the studies used specimens without an artificial gap, and 44% used a chemical model. S. mutans was the main bacterial species used in microbial caries models.

CONCLUSION

The findings of this review provided an insight into the performance of available dental materials assessed using different recurrent caries models, yet this review cannot be used as a guideline for material selection. Selecting the appropriate restorative material relies on several patient-related factors such as microbiota, occlusion, and diet that are not comprehensively taken into consideration in recurrent caries models and thus hinder reliable comparison.

CLINICAL SIGNIFICANCE

Due to the heterogenicity of variables among studies on the performance of dental restorative materials, this scoping review aimed to provide insights for dental researchers concerning the available recurrent caries models, testing methods used, and aspects of comparison between these materials including their characteristics and limitations.

Trans-cinnamaldehyde loaded chitosan based nanocapsules display antibacterial and antibiofilm effects against cavity-causing Streptococcus mutans

Background

Dental caries is a multifactorial disease, and the bacteria such as Streptococcus mutans (S. mutans) is one of the risk factors. The poor effect of existing anti-bacterial is mainly related to drug resistance, the short time of drug action, and biofilm formation.

Methods

To address this concern, we report here on the cinnamaldehyde (CA) loaded chitosan (CS) nanocapsules (CA@CS NC) sustained release CA for antibacterial treatment. The size, ζ-potential, and morphology were characterized. The antibacterial activities in vitro were studied by growth curve assay, pH drop assay, biofilm assay, and qRT-PCR In addition, cytotoxicity assay, organ index, body weight, and histopathology results were analyzed to evaluate the safety and biocompatibility in a rat model.

Results

CA@CS NC can adsorb the bacterial membrane due to electronic interaction, releasing CA slowly for a long time. At the same time, it has reliable antibacterial activity against S. mutans and downregulated the expression levels of QS, virulence, biofilm, and adhesion genes. In addition, it greatly reduced the cytotoxicity of CA and significantly inhibited dental caries in rats without obvious toxicity.

Conclusion

Our results showed that CA@CS NC had antibacterial and antibiofilm effects on S. mutans and inhibit dental caries. Besides, it showed stronger efficacy and less toxicity, and was able to adsorb bacteria releasing CA slowly, providing a new nanomaterial solution for the treatment of dental caries.

Novel bioactive dental restorations to inhibit secondary caries in enamel and dentin under oral biofilms

OBJECTIVE

To provide the first review on cutting-edge research on the development of new bioactive restorations to inhibit secondary caries in enamel and dentin under biofilms. State-of-the-art bioactive and therapeutic materials design, structure-property relationships, performance and efficacies in oral biofilm models.

DATA, SOURCES AND STUDY SELECTION

Researches on development and assessment new secondary caries inhibition restorations via in vitro and in vivo biofilm-based secondary caries models were included. The search of articles was carried out in Web of Science, PubMed, Medline and Scopus.

CONCLUSIONS

Based on the found articles, novel bioactive materials are divided into different categories according to their remineralization and antibacterial biofunctions. In vitro and in vivo biofilm-based secondary caries models are effective way of evaluating the materials efficacies. However, new intelligent and pH-responsive materials were still urgent need. And the materials evaluation should be performed via more clinical relevant biofilm-based secondary caries models.

CLINICAL SIGNIFICANCE

Secondary caries is a primary reason for dental restoration failures. Biofilms produce acids, causing demineralization and secondary caries. To inhibit dental caries and improve the health and quality of life for millions of people, it is necessary to summarize the present state of technologies and new advances in dental biomaterials for preventing secondary caries and protecting tooth structures against oral biofilm attacks. In addition, suggestions for future studies are provided.

Immobilizing Bactericides on Dental Resins via Electron Beam Irradiation

Polymerizable bactericides, such as quaternary ammonium compound-based monomers, have been intensively studied as candidates for immobilizing antibacterial components on dental resin. However, they predominantly exhibit a bacteriostatic behavior, rather than bactericidal, as the immobilized components are left with insufficient molecular movement to disrupt the bacterial surface structure through contact-mediated action. In this study, we developed a novel strategy to increase the density of the immobilized bactericide and enhance its antibacterial/antibiofilm properties by combining a surface-grafting technique with electron beam irradiation. A solution of the quaternary ammonium compound-based monomer, 12-methacryloyloxydodecylpyridinium bromide (MDPB), was coated on polymethyl methacrylate (PMMA) resin specimens at the concentrations of 30, 50, and 80 wt%. The coated resins were subsequently exposed to 10 MeV of electron beam irradiation at 50 and 100 kGy, followed by thermal stabilization at 60 °C. The antibacterial effect was evaluated by inoculating a Streptococcus mutans suspension on the coated PMMA resin samples, which exhibited bactericidal effects even after 28 d of aging (P < 0.05, Tukey's honestly significant difference test). Transmission electron microscopy and bacteriolytic activity evaluation revealed that the S. mutans cells had sustained membrane depolarization. Furthermore, the antibiofilm effects against S. mutans and bacteria collected from human saliva were assessed. The thickness and the percentage of membrane-intact cells of the S. mutans and multispecies biofilms formed on the MDPB-immobilized surfaces were significantly lower than the uncoated PMMA specimens, even after 28-d aging (P < 0.05, Tukey's honestly significant difference test). Thus, the immobilization of antibacterial MDPB via electron beam irradiation induced rapid membrane depolarization, increasing membrane permeability and eventually causing cell death. Our strategy substantially enhances the antibacterial properties of the resinous materials and inhibits biofilm formation, therefore demonstrating significant potential for preventing infectious diseases in the oral environment.

Adhesion of Flowable Resin Composites in Simulated Wedge-Shaped Cervical Lesions: An In Vitro Pilot Study

The resin composite restoration of non-carious cervical lesions (NCCLs) still faces some drawbacks mostly related to the quality of the marginal seal. This study attempts to evaluate the adhesive capacities of two flowable and two conventional hybrid resin composite restorations of NCCLs having two types of cervical margins. Our null hypothesis assumes the same adhesive behavior of different materials. The relative composition of dental–restoration structures was also measured. Thus, restored wedge-shaped cervical cavities were realized on both the buccal and oral surfaces of extracted teeth. After immersion in dye solution, sectioning of the teeth was performed. We proposed an optical microscopy method to quantify the dye penetration along the restoration–tooth interface and scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDX) to evaluate the quality of the peripheral seal. The data obtained revealed an amount of dentinal microleakage for all tested materials, despite the favorable results of the restoration peripheral seal. Therefore, data from this study failed to reject the null hypothesis. The adhesion is not influenced by the position of cervical margins. The SEM revealed occasional disruptions of the adhesive interface. EDX sustains the qualitative compositions as provided by the manufacturers. Conclusions: The four experimental composites are recommended to restore NCCLs in clinic.

Development of novel surface coating composed of MDPB and MPC with dual functionality of antibacterial activity and protein repellency

Resin-based reconstructive/restorative materials with antibacterial effects are potentially useful for preventing dental and oral diseases. To this end, the immobilization of an antibacterial component on the surface of a resin by incorporating polymerizable bactericide such as a quaternary ammonium compound-monomer 12-methacryloyloxydodecylpyridinium bromide (MDPB) is an effective technique. However, the effectiveness of immobilized bactericide is reduced by salivary protein coverage. We address this issue by utilizing 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer, which exhibits protein repellency, with MDPB to fabricate a novel copolymer, which served as a surface coating on a methacrylate-based resin. This coating provided a more hydrophilic surface than that provided by MDPB coating and reduced the adsorption of bovine serum albumin and salivary protein. To evaluate bacterial growth on the contact surface, Streptococcus mutans suspension was placed on the coated specimen. After 24-h incubation, MDPB/MPC copolymer exhibited killing effects against S. mutans. Moreover, confocal laser scanning microscopy and scanning electron microscopy were used to evaluate biofilm formation after 48-h incubation in S. mutans suspension, which revealed sparse biofilm and dead bacteria in biofilm on the surface coated with MDPB/MPC. Overall, the proposed surface coating on dental resins exhibited protein-repellent ability and inhibitory effects against bacteria and oral biofilms.

Investigations on the adhesion of new composites for restoring cervical lesions using energy dispersive X-ray analysis and scanning electron microscopy

Restoration of noncarious cervical lesions with resin composites is one of the treatment options, but the retention of the restorations located at the crown-root junction is still a cause of clinical concern. The aim of this study was to evaluate the adhesive properties of three experimental resin composites and two commercial materials used to restore cavities prepared on extracted teeth as well as to determine the relative elemental composition of these materials. We tested the null hypothesis, which considered that the adhesive behaviours of different resin composites did not differ. The microleakage test using tracers showed that all tested materials exhibited some degree of dentinal microleakage, although they all had good dentinal adhesion. The results failed to reject the null hypothesis. The scanning electron microscopy revealed completely adapted adhesive interfaces underneath the restorations along with well-developed hybrid layers depending on the adhesive system. Energy dispersive X-ray analysis analyses showed that the restorative materials have similar chemical compositions, with some differences between the samples from the same material. The results support the implementation of experimental resins in clinical settings.

Secondary Caries in situ Models: A Systematic Review

In situ caries research serves as a bridge between clinical research and laboratory studies. In this kind of research, volunteers wear a removable intraoral splint or prosthesis containing research samples. Many different in situ models exist to investigate secondary caries. This systematic review compared currently existing secondary caries models and their lesion progression per day values.

MATERIALS AND METHODS

Three databases (Medline, Embase, and Cochrane) were searched for relevant literature. Bias risk was assessed and model parameters and caries-related outcomes were extracted by 2 independent researchers. Where possible, caries-related outcomes were normalized by estimating lesion progression per day by dividing lesion depth extracted from microradiographic or microhardness data by the number of days the study lasted.

RESULTS

The literature search identified 335 articles. After eliminating duplicates and selection, 31 articles were included. The models differed greatly on factors such as sample location, presence of fluoride in the model, and analysis methods. Three main groups could be identified by sample placement; 68% of models placed samples palatally in the upper jaw, and the lower jaw model could be divided into the buccal (26%) and approximal (6%) areas. Average lesion progression in enamel next to composite was 4.3 ± 2.8 µm (range1.1-8.8 µm/day).

DISCUSSION

Studies conducted with palatal models showed caries progression rates 2-5 times higher than the estimated clinical progression rates. Lesion progression per day could be a useful tool for future comparison of models and establishing a standardized model.

Glass ionomer cement inhibits secondary caries in an in vitro biofilm model

OBJECTIVES

The objective of this study was to investigate the effect of different glass ionomer cements on secondary caries inhibition in a fully automated in vitro biofilm model.

MATERIALS AND METHODS

One hundred and twenty-four extracted third molars received class V cavities and were filled with one conventional (Ketac Molar/KM), and two resin-modified glass ionomer cements (Photac Fil/PF, Ketac N100/KN, 3M Espe). A bonded resin composite (Single Bond Plus/Filtek Supreme XTE) served as control. After 14 days water storage at 37 °C, specimens were thermocycled (10,000 × 5/55 °C). Over a period of 10 days, specimens were subjected to cariogenic challenge for 3/4/6 h/day. Demineralization was caused by Streptococcus mutans (DSM 20523) alternatingly being rinsed over specimens using artificial saliva. After biological loading, teeth were cut longitudinally and demineralization depths were evaluated at the margins and at a distance of 0.5 mm from the margins using fluorescence microscopy. Marginal quality was investigated under a SEM at ×200 magnification.

RESULTS

Four-hour demineralization depths were for enamel margins (EM), enamel (E), dentin margin (DM), and dentin (D) (μm ± SD): KM: EM 12 ± 8, E 33 ± 7, DM 56 ± 11, D 79 ± 6; PF: EM 19 ± 13, E 34 ± 13, DM 53 ± 10, D 77 ± 12; and KN: EM 26 ± 5, E 38 ± 6, DM 57 ± 11, D 71 ± 7. For all glass ionomer cements (GICs), demineralization depth at the margins was less compared to 0.5 mm distance, with demineralization depth having been correlated to duration of cariogenic challenge (ANOVA [mod. LSD, p < 0.05]). Compared to the bonded resin composite, all GICs exhibited caries inhibition at restoration margins in enamel and dentin.

CONCLUSIONS

Fluoride-releasing GIC materials exhibit a secondary caries inhibiting effect in vitro.

CLINICAL RELEVANCE

Glass ionomer cements have a higher secondary caries inhibiting effect than resin composites.

Caries-resistant bonding layer in dentin

The present study examined the mechanism for caries resistance and the pulp responses in vital teeth following the use of the augmented-pressure adhesive displacement technique. Dentin adhesives were applied to the surface of sound dentin disks in 4 experimental groups: non-antibacterial adhesive and gentle adhesive displacement (N-G), non-antibacterial adhesive and augmented-pressure adhesive displacement (N-H), antibacterial adhesive and gentle adhesive displacement (A-G), antibacterial adhesive and augmented-pressure adhesive displacement (A-H). The depth of demineralization induced by biological or chemical demineralization models was measured using confocal laser scanning microscopy and analyzed with two-way ANOVA. Pulp responses of vital dog's teeth to the augmented-pressure adhesive displacement technique were evaluated using light microscopy. Depth of demineralization was significantly affected by "adhesive type" and "intensity of adhesive displacement" for biological demineralization. For chemical demineralization, only "intensity of adhesive displacement" showed significant influence on lesion depth. Pulp response of 0.1, 0.2 and 0.3 MPa groups showed only moderate disorganization of the odontoblast layer at 24 hours that completely re-organized after 3 weeks. Augmented-pressure adhesive displacement improves the caries resistance property of bonded dentin and does not cause irreversible pulpal damage to vital teeth when the air pressure employed is equal or smaller than 0.3 MPa.

Effect of microparticulate silver addition in dental adhesives on secondary caries in vitro

OBJECTIVES

The aim of the present study was evaluate the effect of microparticulate silver additions in adhesives on secondary caries formation using an artificial mouth model.

MATERIALS AND METHODS

One hundred eight intact human third molars received standardized Class-V resin composite restorations (Filtek Supreme XTE bonded with Syntac, Scotchbond 1 XT, Futurabond M). Adhesives were charged with different amounts of microparticulate silver (0 %/0.1 %/0.5 %). After storage for 4 weeks at 37 °C, teeth were subjected to 10,000 thermocycles (+5 °C and +55 °C), and impressions were taken. Streptococcus mutans 10449 was used in a nutrition medium for secondary caries simulation in a fully automated artificial mouth. After completion of thermocycling and biological load cycling, impressions were taken and replicas were investigated under a light microscope for gap widths at enamel and dentin margins. Evaluation of fluorescence was carried out using a special FITC filter. The demineralization depths at the cavity margin were evaluated using Xpert for Windows working at a pixel distance of 5 μm.

RESULTS

After thermocycling, no difference in gap widths and demineralization depths was found (p > 0.05). After incubation, gap widths and demineralization depths were significantly reduced with higher amounts of silver loading in most of the adhesives (p < 0.05). The 0.5 % silver addition resulted in a slight decrease of secondary caries at resin-dentin margins (p < 0.05).

CONCLUSIONS

Addition of microparticulate silver in commercially available dental adhesives has the potential of reducing secondary caries.

CLINICAL RELEVANCE

The chosen setup was able to produce secondary caries with a distinct in vivo appearance. Microparticulate silver additions in dental adhesives may have an impact on inhibition of secondary caries.

Novel calcium phosphate nanocomposite with caries-inhibition in a human in situ model

OBJECTIVES

Secondary caries at the restoration margins remains the main reason for failure. Although calcium phosphate (CaP) composites are promising for caries inhibition, there has been no report of CaP composite to inhibit caries in situ. The objectives of this study were to investigate the caries-inhibition effect of nanocomposite containing nanoparticles of amorphous calcium phosphate (NACP) in a human in situ model for the first time, and to determine colony-forming units (CFU) and Ca and P ion concentrations of biofilms on the composite restorations.

METHODS

NACP with a mean particle size of 116 nm were synthesized via a spray-drying technique. Two composites were fabricated: NACP nanocomposite, and control composite filled with glass particles. Twenty-five volunteers wore palatal devices containing bovine enamel slabs with cavities restored with NACP or control composite. After 14 days, the adherent biofilms were collected for analyses. Transverse microradiography determined the enamel mineral profiles at the margins, and the enamel mineral loss ΔZ was measured.

RESULTS

NACP nanocomposite released Ca and P ions and the release significantly increased at cariogenic low pH (p<0.05). Biofilms on NACP nanocomposite contained higher Ca (p=0.007) and P ions (p=0.005) than those of control (n=25). There was no significant difference in biofilm CFU between the two composites (p>0.1). Microradiographs showed typical subsurface lesions in enamel next to control composite, but much less lesion around NACP nanocomposite. Enamel mineral loss ΔZ (mean±sd; n=25) around NACP nanocomposite was 13.8±9.3 μm, much less than 33.5±19.0 μm of the control (p=0.001).

SIGNIFICANCE

Novel NACP nanocomposite substantially reduced caries formation in a human in situ model for the first time. Enamel mineral loss at the margins around NACP nanocomposite was less than half of the mineral loss around control composite. Therefore, the Ca and P ion-releasing NACP nanocomposite is promising for caries-inhibiting restorations.

Natural enamel caries in polarized light microscopy: differences in histopathological features derived from a qualitative versus a quantitative approach to interpret enamel birefringence

Lesion area measurement of enamel caries using polarized light microscopy (PLM) is currently performed in a large number of studies, but measurements are based mainly on a mislead qualitative interpretation of enamel birefringence in a single immersion medium. Here, five natural enamel caries lesions are analysed by microradiography and in PLM, and the differences in their histopathological features derived from a qualitative versus a quantitative interpretation of enamel birefringence are described. Enamel birefringence in different immersion media (air, water and quinoline) is interpreted by both qualitative and quantitative approaches, the former leading to an underestimation of the depth of enamel caries mainly when the criterion of validating sound enamel as a negatively birefringent area in immersion in water is used (a current common practice in dental research). Procedures to avoid the shortcomings of a qualitative interpretation of enamel birefringence are presented and discussed.

Caries-preventive effect of resin-modified glass-ionomer cement (RM-GIC) versus composite resin: a quantitative systematic review

AIM

To determine whether resin-modified glass-ionomer cement (RM-GIC), when compared with composite resins (CR), offers a significant caries-preventive effect.

STUDY DESIGN

Quantitative systematic review.

METHODS

Five databases were searched until 29 July 2010. Inclusion criteria were: relevant to review question related to orthodontic or restorative treatment; published in English; prospective clinical 2-arm study. Exclusion criteria were: no computable data reported; study groups not followed up in the same way. References of included articles were checked. The outcome measure was absence of carious lesions. Dichotomous datasets for both groups were extracted from accepted trials. Trials were assessed for selection-, detection/performance, attrition and publication bias.

RESULTS

Of the 11 trials included, 6 were accepted and 24 datasets extracted; 17 datasets showed no difference after 4 weeks to >25 months. There were 7 datasets that favoured (p < 0.05) RM-GIC after 12 - 24 months. The results are limited by risk of selection-, detection-/performance bias and attrition bias. Risk of publication bias was identified.

CONCLUSIONS

The overall results showed either no difference between the materials, or indicated that RM-GIC has a superior caries-preventive effect. The clinical meaning of this result remains uncertain due to risk of bias. High-quality randomised control trials are needed in order to answer the review question conclusively.

Chemical and crystallographic study of remineralized surface on initial carious enamel treated with Galla chinensis

To investigate the morphologic, chemical and crystallographic characters of remineralized surface on initial carious enamel treated with Galla chinensis, scanning electron microscopy equipped with energy dispersive analysis spectroscopy were used, and X-ray microdiffraction (microzone XRD) was used for the first time to analyze in situ the microzone crystallite of remineralized surface on carious enamel. Bovine sound enamel slabs were demineralized to produce initial carious lesion in vitro. Then, the lesions were exposed to a pH-cycling regime for 12 days of remineralization. Each daily cycle included 4x1 min applications with one of the three treatments: distilled and deionized water (DDW); 1 g/L NaF; 4 g/L G. chinensis extract (GCE). After the treatments, some rod-like deposits and many irregular prominences were found on GCE-treated enamel surface, and the intensities of Ca and P signals showed a tendency to increase; Ca:P ratio was significantly higher than that of DDW-treated enamel. X-ray microdiffraction showed hydroxyapatite was still the main component of GCE-treated enamel, and the crystallinity was increased, the crystal lattice changed gently with decreased lattice parameter a. These results indicated the potential of GCE in promoting the remineralization of initial enamel carious lesions, and supported the previous hypothesis about GCE mechanism. Combined with the anti-bacteria and demineralization inhibition properties of GCE, the natural G. chinensis may become one more promising agent for caries prevention.

Microbiological or chemical models of enamel secondary caries compared by polarized-light microscopy and energy dispersive X-ray spectroscopy

Different secondary caries models may present different results. The purpose of this study was to compare different in vitro secondary caries models, evaluating the obtained results by polarized-light microscopy (PLM), scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Standardized human enamel specimens (n = 12) restored with different materials (Z250 conventional composite resin-CRZ, Freedom polyacid-modified composite resin-CRF, Vitremer resin-modified glass-ionomer-GIV, and Fuji IX conventional glass-ionomer cement-GIF) were submitted to microbiological (MM) or chemical caries models (CM). The control group was not submitted to any caries model. For MM, specimens were immersed firstly in sucrose broth inoculated with Streptococcus mutans ATCC 35688, incubated at 37 degrees C/5% CO(2) for 14 days and then in remineralizing solution for 14 days. For CM, specimens were submitted to chemical pH-cycling. Specimens were ground, submitted to PLM and then were dehydrated, gold-sputtered and submitted to SEM and EDS. Results were statistically analyzed by Kruskall-Wallis and Student-Newman-Keuls tests (alpha = 0.05). No differences between in vitro caries models were found. Morphological differences in enamel demineralization were found between composite resin and polyacid-modified composite resin (CRZ and CRF) and between the resin-modified glass-ionomer and the glass-ionomer cement (GIF and GIV). GIF showed higher calcium concentration and less demineralization, differing from the other materials. In conclusion, the glass-ionomer cement showed less caries formation under both in vitro caries models evaluated.