Characterization of dynamic process of carious and erosive demineralization - an overview

Effect of heat application on the physicochemical properties of new endodontic sealers: an in vitro and SEM study

Understanding the properties of endodontic sealers is vital for treatment planning. Calcium silicate-based sealers are important in modern endodontics. This study investigates the effect of heat on the physicochemical properties of new calcium silicate sealers, addressing concerns raised by clinicians seeking to combine their benefits with the gutta-percha obturation technique. Five endodontic sealers (AH Plus Bioceramic®, Total Fill® BC®, One-fil® Bioceramic, K-Biocer, Any-seal®) were evaluated. Each sealer (n = 16/group) was either kept at 37 °C or subjected to heat at 60 or 200 °C for 30 s. ISO 6876-2012 standards were used to measure setting time, flow, film thickness, and dimensional changes over time. SEM and EDS were utilized for surface and chemical analysis. Data analysis employed IBM SPSS Statistics version 26 with a 5% significance level for two-sided tests. The sealers' setting times were shortened by heat, except for Total Fill® BC with extended setting time. All sealers had significantly longer setting times than manufacturer specifications. Film thickness increased with temperature, while flow values decreased. K-Biocer sealer showed the highest flow (16.89 ± 0.57 mm) at 200 °C, while Total Fill® sealer had the lowest (15.32 ± 0.62 mm). Shrinkage was significant at 60 °C and 200 °C, with greater shrinkage at 200 °C. Heat caused surface deformations in all sealers. The 200 °C groups exhibited more voids in AH Plus Bioceramic®, Any-seal®, and One-fil® sealers, and higher void area in Total Fill®, One-fil®, and K-Biocer sealers (p value < 0.001). EDX analysis confirmed heat-induced chemical and elemental changes in all tested sealers. Elevated temperature affects the physicochemical properties and structure of the tested endodontic sealers. The consideration of endodontic sealer compatibility is essential when warm gutta-percha obturation techniques are used.

Effects of silver diamine fluoride on demineralization protection after a secondary acid challenge

OBJECTIVE

This investigation describes the effects of 5% sodium fluoride varnish and 38% silver diamine fluoride on demineralization protection of human enamel lesions of three different severities after a secondary acid challenge.

STUDY DESIGN

Specimens underwent color and enamel surface microhardness change measurements after demineralization and treatment events. Transverse microradiography was conducted following the secondary demineralization.

RESULTS

After treatments, enamel surface microhardness change showed that 24-hour lesions treated with fluoride varnish had less rehardening than 24-hour lesions treated with silver diamine fluoride (p<0.05), whereas 144-hour lesions from both treatment groups showed a beneficial decrease in surface microhardness change that was markedly better in samples treated with silver diamine fluoride (p<0.05). After the secondary demineralization, 24- and 144-hour lesions treated with silver diamine fluoride showed a sustained beneficial decrease in enamel surface microhardness change when compared to fluoride varnish-treated samples of the corresponding lesion severity (p<0.05). Transverse microradiography showed no difference between fluoride varnish- and silver diamine fluoride-treated samples of any corresponding lesion severity, indicating that remineralization in both fluoride varnish- and silver diamine fluoride-treated samples was proportional to each other after a secondary acid challenge.

CONCLUSIONS

Using silver diamine fluoride may have comparable benefits to fluoride varnish in mineral loss prevention.

Incorporation of bioactive glass-ceramic into coconut oil for remineralization of incipient carious lesions

This study evaluated the efficacy of incorporating different concentrations of bioactive glass-ceramic (Biosilicate) into coconut oil on the remineralizing potential and surface roughness of white spot lesions. Fragments (6 x 6 x 2mm) of bovine teeth were sectioned and initial microhardness (KHN) and surface roughness (Ra) readings were obtained. The samples were submitted to cariogenic challenge to form white spot lesions and were separated into six groups (n=13): 1) Artificial Saliva (AS); 2) Coconut Oil (CO); 3) CO+2% Biosilicate (CO+2%Bio); 4) CO+5% Biosilicate (CO+5%Bio); 5) 2% Biosilicate Suspension (2% Bio) and 6) 5% Biosilicate Suspension (5% Bio). The treatments for 1 cycle/day were: immersion into the treatments for 5 minutes, rinsing in distilled water, and storage in artificial saliva at 37ºC. After 14 days, KHN and Ra readings were taken. The surface roughness alteration ((Ra) was analyzed (Kruskal-Wallis, Dunn's post-test, p<0.05). CO+2%Bio had higher (p = 0.0013) (Ra followed by CO+5%Bio (p = 0.0244) than AS. The relative KHN and remineralization potential were analyzed (ANOVA, Tukey, p<0.05), and 5% Bio treatment presented a higher relative microhardness than all other groups (p>0.05). The remineralizing potential of all the treatments was similar (p > .05). When Biosilicate was added, the pH of the suspensions increased and the alkaline pH remained during the analysis. Biosilicate suspension is more efficient than the incorporation of particles into coconut oil at white spot lesion treatment. In addition to the benefits that coconut oil and Biosilicate present separately, their association can enhance the remineralizing potential of Biosilicate.

Bonding performance of universal adhesives to eroded dentine: A 6-year evaluation

OBJECTIVES

To evaluate the microtensile bond strength (µTBS) and nanoleakage (NL) of several universal adhesives to eroded dentine (ED) using etch-and-rinse (ER) and self-etch (SE) strategies, immediately and after 6 years of water storage.

MATERIAL AND METHODS

Four hundred and eighty human molars were distributed into 60 groups according to dentine substrate (sound dentine [SD], eroded with soft drink, or eroded with citric acid), application method of the adhesive (SE or ER), and the adhesives used: 1. All-Bond Universal, 2. Ambar Universal, 3. Clearfil Universal, 4. Futurabond U, 5. One Coat 7 Universal, 6. Peak Universal Bond, 7. Prime&Bond Elect, 8. Scotchbond Universal, 9. Tetric n-bond Universal, and 10. Xeno Select. The restoration was then performed with a composite resin, and the specimens were sectioned into resin-dentine bonded sticks. The sticks were tested (immediately or after 6 years of storage) for µTBS (0.5 mm/min) or used to assess NL. The eroded dentine surfaces were also examined using FE-SEM to evaluate the NL. Data for µTBS were analyzed by four-way ANOVA and Tukey's post-hoc test (a = 0.05), and the NL was analyzed by Kruskal-Wallis and the Wilcoxon Signed Rank Sum test (a = 0.05).

RESULTS

In ED, there was no difference in μTBS and NL between ER and SE strategies (p > 0.05). Most μTBS and NL values obtained for ED were lower and higher, respectively, than those for SD (p < 0.005). Additionally, the worst results (μTBS and NL) were observed for erosion with citric acid groups in comparison with erosion with soft-drink groups (p < 0.007). After 6y, μTBS was generally lower and NL higher for all substrates, adhesives, and strategies (p < 0.05), except for AMB, SBU, and TEU in dentine eroded with citric acid. The lowest μTBS and highest NL values were observed for ABU, FBU, OCU, PUB, PBE, and XEN in both types of eroded dentine and evaluation times (p < 0.002).

CONCLUSION

The use of MDP-containing adhesives seems to be essential to maintain adhesion to eroded dentine. However, other factors such as acidity should be considered.

CLINICAL SIGNIFICANCE

The bonding of eroded dentine is a challenge. However, the use of MDP-containing universal adhesives showed less degradation after long-term evaluation.

Regenerative biomineralization potential of commercially available remineralizing agents as a preventive treatment approach for tooth erosion - An in vitro laser-induced breakdown spectroscopy analysis

Context

In today's era, erosion is the most prevalent type of tooth wear. The prevention of demineralization with biomineralization is the most desired treatment.

Aim

The aim of this study is to evaluate and compare the surface remineralization potential of two remineralizing agents - self-assembling peptide P11-4 (SAP P11-4) and calcium silicate plus sodium phosphate (CSSP) salts on intact and demineralized enamel using laser-induced breakdown spectroscopy (LIBS).

Subjects and Methods

Sixteen maxillary premolars were decoronated and split into buccal and palatal halves embedded in acrylic resin with a total sample size of 32 designated into Group 1 (intact teeth) and Group 2 (demineralized teeth). Further subdivision into Groups 1a and 2a (SAP P11-4 group [n = 8]); Groups 1b and 2b (CSSP group [n = 8]), Group 2 was first exposed to Coca-Cola. Then, all groups were subjected to experimental LIBS. Groups 1a and 2a were treated with SAP P11-4 based product, i.e., CURODONT™ PROTECT gel. Groups 1b and 2b were treated with CSSP-based products regimen, i.e., REGENERATE Enamel Science™ Advanced Toothpaste and Advanced Enamel Serum. The LIBS assessment was redone for all groups to attain a change in Ca and P values.

Statistical Analysis Used

Inferential statistics were done using Wilcoxon signed-rank test (Before-After product application) and Mann-Whitney U-test (between the groups).

Results

According to the statistical evaluation there was a statistically significant difference (P < 0.05), in Ca and P values in demineralized teeth when both SAP P11-4 and CSSP groups were evaluated. Although Ca values exhibited a significant difference in intact teeth, P did not exhibit a significant difference on the application of both remineralizing agents. The remineralizing potential between the two agents, SAP P11-4 and CSSP groups. There was no statistically significant difference ( P <0.05) observed between the two agent's remineralization potential for intact and demineralized teeth.

Conclusion

SAP P11-4 and CSSP have the potential to remineralize both intact and demineralized enamel. There was increased remineralization in demineralized samples subjected to erosion.

DIAGNOdent versus International Caries Detection and Assessment System in detection of incipient carious lesions: A diagnostic accuracy study

Aim

The present investigation aimed at assessing the diagnostic accuracy of DIAGNOdent compared to the International Caries Detection and Assessment System-II (ICDAS-II) in the detection of facial, smooth surface noncavitated carious lesions.

Settings and Design

Sixty patients were enrolled in the current study according to the eligibility criteria. There were 161 teeth with noncavitated, white spot carious lesions and 32 sound teeth.

Materials and Methods

Before examination, teeth were cleaned and polished and all patients were assessed under standardized operating conditions: preset dental unit position, operating light, and prolonged air drying (approximately 5 s). All teeth were assessed by two calibrated examiners individually without any contact using ICDAS-II and DIAGNOdent.

Statistical Analysis

The diagnostic accuracy of DIAGNOdent device was determined, including sensitivity, specificity, overall accuracy, positive and negative predictive values, and receiver operating characteristic curve analysis. Chi-square test was conducted to compare the distribution of ICDAS-II and DIAGNOdent scores. Inter-observer agreement between assessors was evaluated using Cohen's kappa test.

Results

In the current study, DIAGNOdent had an overall accuracy of 84.45% with sensitivity and specificity of 87.58% and 96.87%, respectively, and +PV and -PV of 97.7% and 83.9%, respectively, when score 0 represented sound tooth surface, while scores 1 and 2 were considered clinically noncavitated carious lesions. Moreover, when only ICDAS score 1 was considered representing first visual change in enamel, DIAGNOdent had an accuracy of 74.15% with sensitivity and specificity of 83.53% and 90.62%, respectively, and +PV and -PV of 93% and 78.6%, respectively. In the present study, when only ICDAS score 2 was considered representing distinct visual change in enamel, DIAGNOdent had an accuracy of 100% with sensitivity and specificity of 100% and 100%, respectively, and +PV and -PV of 100% and 100%, respectively.

Conclusions

The overall performance of DIAGNOdent was equivalent to the visual inspection using ICDAS-II. DIAGNOdent might be considered a useful adjunctive device for detection and monitoring development of noncavitated carious lesions on facial smooth surfaces.