Erosion of dentine and enamel in vitro by dietary acids: the effect of temperature, acid character, concentration and exposure time

Advances in Preventive and Therapeutic Approaches for Dental Erosion: A Systematic Review

This review discusses both preventive measures and clinically implemented therapy procedures that have been developed recently for the prevention and treatment of tooth erosion.

METHODS

The databases PubMed, Scopus, and Web of Science were used for a thorough search. Studies on the prevention and treatment of dental erosion that were conducted in English and used in vitro were among the inclusion criteria.

RESULTS

The search turned up 391 papers in total, with 34 of those publications matching the requirements for inclusion. Varnishes, toothpastes, and solutions containing fluoride and other substances were used as preventive measures.

CONCLUSIONS

Dental erosion is a significant issue, and taking preventative steps is crucial to lessening the disease's spread and its effects. Interventions based on fluoride seem to be successful at halting erosion and encouraging remineralization. To effectively address severe tooth erosion, therapeutic methods, including composite restorations, prosthetic crowns, and veneers, are available. Dental erosion causes aesthetic and functional issues that are best addressed with less invasive treatments like direct composite restorations. To improve and broaden the range of available treatments for this common dental issue, additional research and development are required.

Growth Factor release and dental pulp stem cell attachment following dentine conditioning- an in vitro study

Aim

The aim of the study was to investigate the effect of dentine conditioning agents on growth factor liberation and settlement of dental pulp progenitor cells (DPSCs) on dentine surfaces.

Methodology

The agents used included ethylenediaminetetraacetic acid (EDTA; 10%, pH 7.2), phosphoric acid (37%, pH < 1), citric acid (10%, pH 1.5) and polyacrylic acid (25%, pH 3.9). Human dentine slices were conditioned for exaggerated conditioning times of 5 and 10 min, so that the growth factor liberation reached quantifiable levels above the limit of detection of the laboratory methods employed. Transforming growth factor beta‐1 (TGF‐β1) release and surface exposure were quantified by enzyme‐linked immunosorbent assay (ELISA) and immunogold labelling. Scanning electron microscopy (SEM) was used to assess the morphology of cells and coverage by DPSCs cultured on dentine surfaces for 8 days.

Results

After 5‐min conditioning of dentine slices, citric acid was the most effective agent for growth factor release into the aqueous environment as measured by ELISA (Mann–Whitney U with Bonferroni correction, p < .01 compared with phosphoric and polyacrylic acid). As well as this, dentine slices treated with phosphoric acid for the same period, displayed significantly less TGF‐β1 on the surface compared with the other agents used, as measured by immunogold labelling (MWU with Bonferroni correction, p < .05). After 8 days, widespread coverage by DPSCs on dentine surfaces conditioned with citric acid and EDTA were evident under SEM. On dentine surfaces conditioned with phosphoric and polyacrylic acid, respectively, less spread cells and inconsistent cell coverage were observed.

Conclusions

Based on the findings of this in vitro study, a desirable biological growth factor‐mediated effect may be gained when conditioning dentine by milder acidic or chelating agents such as citric acid and EDTA. The results must be interpreted in the context that the potential of the applied materials inducing a desirable biological response in DPSCs is only one consideration amongst other important ones in a clinical setting. However, it is crucial to look beyond the mere physical effects of materials and move towards biologically based treatment approaches as far as the restorative management of teeth with viable dental pulps are concerned.

Role of bioglass in enamel remineralization: Existing strategies and future prospects-A narrative review

Enamel, once formed, loses the ability to regenerate due to the loss of the formative ameloblasts. It is subjected to constant damaging events due to exposure to external agents and oral microbiomes. An enamel remineralization process targets to replenish the lost ionic component of the enamel through a multitude of methods. Enamel remineralization is highly challenging as it has a complex organized hierarchical microstructure. Hydroxyapatite nanocrystals of the enamel vary in size and orientation along alignment planes inside the enamel rod. The inability of the enamel to remodel unlike other mineralized tissues is another substantial deterrent. One of the well-known biomaterials, bioglass (BG) induces apatite formation on the external surface of the enamel in the presence of saliva or other physiological fluids. Calcium, sodium, phosphate, and silicate ions in BG become responsive in the presence of body fluids, leading to the precipitation of calcium phosphate. Studies have also demonstrated the bactericidal potential of BG against Streptococcus mutans biofilms. The anticariogenicity and antibacterial activity were found to be enhanced when BG was doped with inorganic ions such as F, Ag, Mg, Sr, and Zn. Due to the versatility of BG, it has been combined with a variety of agents such as chitosan, triclosan, and amelogenin to biomimic remineralization process. Key strategies that can aid in the development of contemporary enamel remineralization agents are also included in this review.

Effect of black tea and matrix metalloproteinase inhibitors on eroded dentin in situ

Purpose of this in situ study was to evaluate the surface properties of eroded dentin specimens activated with three different matrix metalloproteinase (MMP) inhibitors (chlorhexidine [CHX], fluoride, green tea), black tea, and water. One hundred eighty dentin samples were prepared from extracted third molars and then samples divided into six groups. Ten volunteers were carried three specimens of each group, on acrylic palatal appliances, which were fabricated exactly for them (n = 3). Erosive cycles were done by immersing appliances in cup containing Cola and was followed by rinsing with test solutions. Microhardness values were measured. Surface properties were investigated by atomic force microscopy (AFM). Lowest change in microhardness was shown in fluoride group whereas negative control group (water) had the highest change. There were no statistically significant differences among surface roughness changes (p > .05). The least change in microhardness was seen in the fluoride group (13.05 ± 8.07), while the control group showed the highest change (33.80 ± 12.42) and was statistically significant when compared to other groups (p < .05). Besides lowest depth, values were shown in fluoride group as well. AFM evaluations showed macromolecular deposits on surfaces of fluoride, CHX, and black tea groups. No superior results were detected in CHX + fluoride group and black tea showed similar surface characteristics as green tea. Mouthrinses containing not only green tea but also black tea could be beneficial for patients with exposed dentin surfaces. Catechines and theaflavins in teas could be useful for improving surface quality.

Frequency of Application of AmF/NaF/SnCl2 Solution and Its Potential in Controlling Human Enamel Erosion Progression: An in situ Study

Although several studies have demonstrated the efficacy of AmF/NaF/SnCl2 solution in inhibiting dental erosion progression, measures for further improvement in its effectiveness are paramount. Thus, this in situ study evaluated whether the protective effect promoted by the AmF/NaF/SnCl2 solution would be enhanced by increasing its frequency of use. The study was conducted with 12 volunteers, a 4-phase (5 days each) randomized, crossover model. Extraoral erosive challenges (0.5% citric acid, pH 2.6, 6 × 2 min/day) and rinsing protocol (1 or 2 × 2 min/day) were performed. Before the in situ phase, human enamel samples were subjected to an in vitro surface softening (1% citric acid, pH 4.0, for 3 min). Four treatment protocols were tested using samples in replicas (n = 12): group G1 - deionized water (negative control); G2 - NaF solution (positive control, 500 ppm F-, pH 4.5); G3 - AmF/NaF/SnCl2 solution (500 ppm F-, 800 ppm Sn2+, pH 4.5) once a day; G4 - AmF/NaF/SnCl2 solution twice a day. Tissue loss and morphological changes were determined by optical profilometry (n = 12) and scanning electron microscopy (n = 3) analysis, respectively. Data were statistically analyzed by ANOVA with subsequent pairwise comparison of treatments. Tissue loss means (±SD in µm) for each treatment protocol and statistical differences were found as follows: G1 4.55 ± 2.75, G2 4.59 ± 2.13, G3 2.64 ± 1.55, and G4 1.34 ± 1.16. Although there was no difference between the 2 AmF/NaF/SnCl2 solution application regimens (once or twice a day), application of the product twice a day was the only treatment that was able to control erosion progression, differing from the control groups.

Effects of Erosion Protocol Design on Erosion/Abrasion Study Outcome and on Active Agent (NaF and SnF2) Efficacy

There is no standard for testing anti-erosive/anti-abrasive agents, making the assessment and comparison of study results difficult. Factors which are varied in study designs are amongst others the erosive medium regarding concentration and pH or movement type of acid. The present study therefore investigated the impact of these factors on dimension of tissue loss and on efficacy of active agents used as anti-erosive/anti-abrasive therapeutics. In 8 experiments, consisting of 8 groups each (n = 20 each), resulting in a total of 64 groups, enamel specimens were demineralised (10 days, 6 × 2 min/day) using different acids (1, 0.5 and 0.3% citric acid at native pH 2.3, 2.5 and 2.8, respectively, and 0.3% citric acid adjusted to pH 3.6) with two different movement types (jerky or smooth). Specimens were immersed (2 × 2 min/day) in slurries of 1,450 ppm F- toothpaste (NaF), 1,450 ppm F- and 3,436 ppm Sn2+ toothpaste (NaF/SnF2), 970 ppm F- and 3,000 ppm Sn2+ gel (SnF2) or placebo, or were additionally brushed during immersion (15 s, 200 g). All groups were in between stored in a mineral salt solution. Tissue loss was determined profilometrically. Movement type, pH and concentration of acid had a substantial impact on study outcome. The combination of jerky movement and concentrated acid masked, to some extent, differences between erosive and erosive-abrasive tissue loss. The acid at low concentration (0.3%), independent of pH, was too mild to produce any tissue loss. The model with the best ability to demonstrate effects of abrasive impacts and active agents used the 1% acid concentration combined with smooth acid movements.