Evaluating a method of creating artificial caries in typodont teeth for teaching Class III cavity preparations

OBJECTIVES

The purpose of the study was to report a step-by-step process of creating artificial caries typodont teeth and to determine the perception and efficacy of their use in preclinical operative training.

METHODS

Artificial caries material comprised of commercially available hide glue and chocolate powder for more realistic coloring was embedded into the distolingual of #9 ModuPRO plastic typodont teeth. First-year dental students having no clinical experience in excavating Class III cavity preparations were divided into two groups. Group BA prepared conventional typodont teeth (CTT) first, then artificial caries typodont teeth. Group AB prepared the ACT first, then CTT. The preps were scored employing a rubric used in the operative dentistry course class. A feedback questionnaire was conducted to rate students' satisfaction regarding the use of ACT and CTT. The Mann-Whitney U-test was used to compare the scores between groups ACT-CTT and CTT-ACT and the Chi-Square test was used to evaluate the positive and negative questionnaire responses.

RESULTS

The two groups showed no significant difference in grades and no significant changes in their scores regardless of which order they prepped the teeth (P > 0.05). The questionnaire heavily favored the use of artificial caries typodont teeth (P < 0.05).

CONCLUSIONS

The artificial caries typodont teeth protocol described in this study was feasible when implemented at the preclinical laboratory instruction level with positive questionnaire feedback from dental students.

Inhibition of root dentin demineralization by ion releasing cements

OBJECTIVES

To compare the ability of resin-modified glass ionomer (RMGI) and bioactive cements to prevent root dentin demineralization.

MATERIALS AND METHODS

Fifty molars were prepared at the cementum-enamel junction (n = 10) and restored with three bioactive cements (Activa Bioactive Cement, ACT; Ceramir Crown and Bridge, CER; and Theracem, THE), a self-adhesive resin cement (Rely X Unicem 2, UNI), and a RMGI cement (Rely X Luting Plus, LUT). Specimens were cycled for 30 days between a demineralization solution (pH = 4) composed of 0.1 M lactic acid and 3 mM Ca₃ (PO₄ )₂ for 4 hours and a remineralization solution (pH = 7.0) composed of 1.5 mM Ca, 0.9 mM P, and 20 mM Tris(hydroxymethyl)-aminomethane for 20 hours. Specimens were sectioned to 100 μm and evaluated with polarized light microscopy. A line was drawn parallel with the zone of demineralization for each tooth. The areas of "inhibition" (external to the line) were measured as positive values and "wall lesions" (pulpal to the line) were measured as negative areas.

RESULTS

Significant differences were found between materials for "inhibition/wall lesion" areas in root dentin (P < .001) and ranked as (μm² , mean ± SD): LUT (7700 ± 2500) > CER (3800 ± 1900), THE (2100 ± 2600), and ACT (1400 ± 700) > UNI (-2000 ± 1700).

CONCLUSIONS

Bioactive cements showed net areas of demineralization inhibition albeit at a lower level than a reference RMGI cement.

CLINICAL SIGNIFICANCE

RMGI or bioactive cements may be indicated for patients at risk of secondary caries around crown margins.

An In-Vitro Comparative Evaluation of Pre-treatment With Nano-Silver Fluoride on Inhibiting Secondary Caries at Tooth Restoration Interface

Introduction and aim

Dental caries is the global burden worldwide and has a negative effect on the quality of life. Restorative materials in pediatric dentistry have shown satisfactory properties; however, the highest failures are still reported due to the occurrence of secondary caries. The article aims to assess the effectiveness of pre-treatment with nano-silver fluoride (NSF) in inhibiting secondary caries at the tooth restoration interface.

Materials and methods

Forty tooth specimens were prepared from 20 newly extracted human premolar teeth by sectioning the tooth mesiodistally. Class V cavities were prepared on each specimen at enamel dentin junction. Specimens were randomly distributed into four groups (n=10): 1) glass ionomer cement (GIC) restoration, 2) composite restoration 3) NSF pre-treatment + GIC restoration, 4) NSF pre-treatment + composite restoration. After sterilization, specimens were subjected to artificial caries formation by pH cycling method for 14 days. Specimens were sectioned and mounted to evaluate the demineralization by using the Vickers microhardness test. Outer lesion depth was measured at the tooth restoration interface on digital radiographs. Data was analyzed using Student unpaired t-test, one-way ANOVA, and Tukey honestly significant difference (HSD) post hoc test.

Results

The mean microhardness value of pre-treated GIC and composite group with NSF was more than the non-treated NSF group, with a significant difference at the enamel, indicating lesser demineralization. Outer lesion depth was lesser in the pre-treated group showing better tooth restoration integrity with a statistically significant difference between the groups.

Conclusion

Pre-treatment with NSF is beneficial in increasing the resistance of GIC and composite resin restoration to secondary caries formation.

Comparison of Remineralising Potential of Nano Silver Fluoride, Silver Diamine Fluoride and Sodium Fluoride Varnish on Artificial Caries: An In Vitro Study

PURPOSE

To evaluate the remineralisation effect of an experimental nano silver fluoride (NSF) formulation using an in vitro remineralisation model, compared with silver diamine fluoride (SDF) and sodium fluoride varnish (NaF) in current clinical use.

MATERIALS AND METHODS

45 sound human third molars were sectioned in buccolingual and mesiodistal direction and 180 enamel specimens were divided into four groups (NSF; SDF; NaF; Control). Early caries-like lesions were artificially created. Remineralisation agents were applied with a microbrush for 2 min in NSF and SDF group; NaF varnish were applied in a thin layer and then all specimens were stored in a moist environment at 37°C for 24 h. Each group was subjected to a pH cycling model for 7 days. The Vickers microhardness values (VHN) of specimens were compared before treatment, after demineralisation and after remineralisation. In addition, scanning electron microscope (SEM) images were investigated to compare morphological changes on the surfaces. Kruskal-Wallis and Mann-Whitney U tests were used for statistical analysis to compare the groups at p < 0.05.

RESULTS

All remineralisation agents were found to be statistically significant for the rehardening of the demineralised enamel specimens (p < 0.001). There was a statistically significant difference between the all groups after remineralisation (p < 0.001). The VHN values for postdemineralisation were determined as, respectively, NaF (229.96) > SDF (222.96) > NSF (191.36) > Control (175.80). SEM images have also supported the microhardness values.

CONCLUSIONS

NSF was not found to be effective as sodium fluoride varnish and SDF on artificial enamel caries lesions. Additional investigation is needed to recommend it as an alternative agent to routine fluoride treatments.

In vitro biofilm models to study dental caries: a systematic review

The aim of this systematic review is to characterize and discuss key methodological aspects of in vitro biofilm models for caries-related research and to verify the reproducibility and dose-response of models considering the response to anti-caries and/or antimicrobial substances. Inclusion criteria were divided into Part I (PI): an in vitro biofilm model that produces a cariogenic biofilm and/or caries-like lesions and allows pH fluctuations; and Part II (PII): models showing an effect of anti-caries and/or antimicrobial substances. Within PI, 72.9% consisted of dynamic biofilm models, while 27.1% consisted of batch models. Within PII, 75.5% corresponded to dynamic models, whereas 24.5% corresponded to batch models. Respectively, 20.4 and 14.3% of the studies reported dose-response validations and reproducibility, and 32.7% were classified as having a high risk of bias. Several in vitro biofilm models are available for caries-related research; however, most models lack validation by dose-response and reproducibility experiments for each proposed protocol.

Remineralization Potential of Three Tooth Pastes on Enamel Caries

BACKGROUND:

Different formulations of dentifrices exist in the market. Usually, single toothpaste is used by all family members including children. There is a big concern of fluoride ingestion with the toothpaste containing high fluoride content in children. Recently, new toothpaste (including toothpaste) with remineralization potential without fluoride content has been formulated.

AIM:

There is an urgent need to compare remineralization potential of this new formulation with the exiting dentifrices. Therefore, the present study has been undertaken to assess and compare the remineralization potential of three dentifrices with different compositions on artificially induced carious lesions in vitro by using scanning electron microscopy and polarised light microscopy.

MATERIALS AND METHODS:

The present in vitro study was conducted on 21 healthy extracted primary central incisor teeth surfaces, which were divided into three groups and were treated by three different dentifrices. Artificial demineralization was followed by remineralization using dentifrice slurry as per the group distribution. All the samples were studied for remineralization by using scanning electron microscopy and polarised light microscopy. Data were analysed using SPSS version 11 software.

RESULTS:

A significant difference was found between the remineralization potential of incudent toothpaste and other toothpaste groups based on the analysis of polarised light microscopy and stereomicroscope. The remineralizing ability of incudent toothpaste for artificial enamel lesions was found to be significantly higher than that of Colgate® and Crest toothpaste.

CONCLUSIONS:

The limitations of this study include, being a short term study, low sample size and in vitro experiment. incudent toothpaste has exhibited a higher remineralizing potential as compared to fluoride based toothpaste in our study.