Dentin Erosion Research Articles

Morphological and chemical effects of in-office and at-home desensitising agents containing sodium fluoride on eroded root dentin

ObjectiveThe aim of this study was to evaluate the morphological and chemical effect of in-office and at-home desensitising agents containing sodium fluoride (NaF) on eroded root dentine in vitro. MethodsFifty bovine dentine samples were pre-eroded and randomised into five groups (n = 10): G1 (Control) - milli-Q water; G2 - fluoride varnish containing NaF 22,500 ppm; G3 - desensitising cream containing NaF 9,000 ppm associated with 20% nanohydroxyapatite; G4 - toothpaste with NaF 5,000 ppm associated to tricalcium phosphate; G5 - toothpaste containing NaF 900 ppm and casein phosphopeptide-amorphous calcium phosphate fluoride (CPP-ACPF). The specimens were submitted to erosive challenge for three days. The analyses were performed using non-contact profilometry for volumetric (Sa) and linear roughness (Ra) followed by scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDS). The data were analysed by Kruskal-Wallis and Wilcoxon tests (α = 0.05). ResultsThere was a significant reduction of Ra and Sa for the eroded samples from the G2 and G5 (p < 0.05) after an erosive challenge. The dentine surface topography pattern showed partially or totally occluded dentinal tubules after treatments, except in the control group. The control, G4 and G3 groups showed a reduction in the dentine inorganic content percentage of Ca (Calcium) and P (Phosphorus) minerals. ConclusionThe fluoride varnish and CPP-ACPF toothpaste were able to prevent morphological changes and were the only materials that showed the Ca and P content increased after treatment. These materials may be promising alternatives in the clinical control of dentin erosion.

The way wear goes: phytolith-based wear on the dentine-enamel system in guinea pigs (Cavia porcellus).

The effect of phytoliths on tooth wear and function has been contested in studies of animal-plant interactions. For herbivores whose occlusal chewing surface consists of enamel ridges and dentine tissue, the phytoliths might particularly erode the softer dentine, exposing the enamel ridges to different occlusal forces and thus contributing to enamel wear. To test this hypothesis, we fed guinea pigs (Cavia porcellus; n = 36 in six groups) for three weeks exclusively on dry or fresh forage of low (lucerne), moderate (fresh timothy grass) or very high (bamboo leaves) silica content representing corresponding levels of phytoliths. We quantified the effect of these treatments with measurements from micro-computed tomography scans. Tooth height indicated extreme wear due to the bamboo diet that apparently brought maxillary incisors and molars close to the minimum required for functionality. There were negative relationships between a cheek tooth's height and the depth of its dentine basin, corroborating the hypothesis that dentine erosion plays an important role in herbivore tooth wear. In spite of lower body mass, bamboo-fed animals paradoxically had longer cheek tooth rows and larger occlusal surfaces. Because ever-growing teeth can only change in shape from the base upwards, this is a strong indication that failure to compensate for wear by dental height-growth additionally triggered general expansive growth of the tooth bases. The results suggest that enamel wear may intensify after enamel has been exposed due to a faster wear of the surrounding dentine tissue (and not the other way around), and illustrate a surprising plasticity in the reactivity of this rodent's system that adjusts tooth growth to wear.

The effect of commercial whitening toothpastes on erosive dentin wear in vitro

ObjectivesThis study evaluated the erosive tooth wear promoted by commercial whitening toothpastes on eroded dentin in vitro. DesignNinety bovine roots were embedded, polished and subjected to the baseline profile analysis. The samples were protected in 2/3 of the dentin surface and were randomly assigned to 6 groups (n = 15/group): Oral-B 3D White; Close-up Diamond Attraction Power White; Sorriso Xtreme White 4D; Colgate Luminous White; Crest and erosion only. All samples were submitted to erosive pH cycles (4 × 90 s in 0.1% citric acid, pH 2.5, per day) and abrasive challenges (2 × 15 s, per day) for 7 days. The samples were subjected to abrasion, using toothbrushing machine, soft toothbrushes and slurries of the tested toothpastes (1.5 N, 1:3 water). Between the challenges, the samples were immersed in artificial saliva. The final profile was overlaid to the baseline profile for the calculation of the erosive dentin wear (μm). The data were subjected to Kruskal-Wallis/Dunn tests (p < 0.05). ResultsColgate Luminous White (4.7 μm) and Sorriso Xtreme White 4D (4.0 μm) promoted the highest wear, similarly to Oral-B 3D White (2.3 μm). Oral-B 3D White promoted similar wear compared to Crest (1.1 μm) and Close-up Diamond Attraction Power White (1.2 μm); however, it induced significant higher dentin wear compared to erosion only (1.0 μm). Close-up Diamond Attraction Power White and Crest did not increase the erosive wear compared to erosion only. ConclusionSome whitening toothpastes increase the wear of eroded dentin, which should be considered by the dentist when prescribing them to patient with root exposure.

Investigation of different sodium hypochlorite volumes, concentrations and times of irrigation in endodontic therapy: a systematic review

Investigation of different sodium hypochlorite volumes, concentrations and times of irrigation in endodontic therapy: a systematic review

STATUS KESEHATAN GIGI &amp; MULUT MASYARAKAT KABUPATEN TIMOR TENGAH UTARA BERDASARKAN FORMAT PEMERIKSAAN WHO ORAL HEALTH SURVEYS BASIC METHODS 5th EDITION

One of the aims of Oral Health Global Goals 2020 is to reduce missing tooth or tooth loss due to dental caries, according with the fact that oral health problems that predominate in the world especially in Indonesia are tooth loss due to caries. Therefore an effort is needed to reduce the missing component through the implementation of good health services that are obtained from good planning, good planning is obtained from the existence of good data as well , good oral health status data obtained from data collectors, instruments and standardized oral examination formats good too. The oral examination format from WHO Oral Health Basic Methods 5th Edition is the latest examination format to record various indicators of oral health status but has not been widely used in determining the oral health status of individuals or communities in Indonesia . Research purposes is to know the community oral health status of the North Central Timor District people in accordance with the latest examination format from WHO Oral Health Surveys Basic Methods 5th Edition. This is a descriptive survey research with a cross sectional design , which was carried out by taking 208 respondents from the community of 5 villages in North Central Timor District, such as Hauteas, Tes, Sainiup, North Oenenu and Homusu village..The data obtained through direct examination by the dentist in the respondent's oral cavity to determine their oral health status and recorded in the WHO Oral Health Surveys Basic Methods 5th Edition examination format. The data will be analyzed descriptively in accordance with the provisions set by WHO. The oral health status of North Central Timor people are: Dentition status, on average there are 8 carious crowns and 10 exposed roots, both carious and not carious. Periodontal status, on average they had 5 teeth with gingival bleeding , whereas for gingival pocket, on average they had 6 teeth with deep gingival pocket 4- 5 mm . Loss of attachment status, on average there are at least 1 sextant with various conditions for periodontal tissue attachment loss, such as 4-5 mm, 6-8 mm, 9-11 mm , and ≥ 12 mm attachment loss from the cemento enamel junction. There is no fluorosis status . Dental erosion status, about 16.19% of them had enamel erosion, and 4.37% had dentine erosion. The average number of teeth with enamel erosion are 12 teeth and those with erosion to the dentin on average are 7 teeth .Oral mucosal lesions, about 3.9% of them had stomatitis aphthous recurrent (SAR), and 1.3% of the people had suspected oral cancer. Denture status, only 0.43 % of the population uses partial removable teeth, and only in the maxilla, the rest there is no denture.Intervention urgency status, about 60.3% of the population need oral health care, but not urgent, about 15.53% of the population do not or do not need oral health care, about 5.24% of the population need oral health care urgently. There are oral health problems among NorthCentral Timor District people, such as carious crowns, exposed roots, gingival bleeding, gingival pocket, loss of attachment periodontal, dental erosion, oral mucosal lessions, and dentureless edentulous, so they need oral intervention.

Using Optical Attenuation Coefficient to Monitor the Efficacy of Fluoride and Nd:YAG Laser to Control Dentine Erosion

The present study evaluated the protective effects that are induced by fluoride and Nd:YAG laser irradiation to control dentine erosion. One hundred and twenty bovine dentine slabs were eroded with citric acid twice a day for a total period of 15 days. At day 10, the samples were randomly assigned into eight groups: C (Control); F (Fluoride); L1 (Nd:YAG laser, 1 W, 100 mJ, 79.5 J·cm−2); L2 (Nd:YAG laser, 0.7 W, 70 mJ, 55.7 J·cm−2); L3 (Nd:YAG laser, 0.5 W, 50 mJ, 39.7 J·cm−2); F + L1; F + L2; and, F + L3. Optical Coherence Tomography images were collected from the surface of the samples in order to monitor the alterations that were induced by erosion and the effectiveness of each treatment using the Optical Attenuation Coefficient (OAC). OAC values that were calculated for samples from groups C, F, L1, L3, FL1, and FL3 indicated no protective effects against the progression of erosive lesions. Samples from L2 and FL2 groups presented OAC values, indicating that laser irradiation under this condition did not induce the formation of craters on dentine tissue and promoted sufficient chemical and morphological changes to avoid the progression of dentine erosion.

Image guided laser ablation of demineralization from root surfaces.

It is challenging to identify demineralized areas of root lesions due to cervical erosion, calculus formation, and heavy staining of dentin. We have found that root caries can be imaged with extremely high contrast at short wavelength IR (SWIR) wavelengths beyond 1500-nm. Lasers are well suited for the selective removal of caries lesions from tooth surfaces. A CO2 laser operating at a wavelength of 9.3-μm was combined with a thulium-doped fiber laser operating at 1880-nm for the selective removal of root caries lesions from extracted teeth. Serial SWIR reflectance images at 1880-nm were used to guide the CO2 laser for image-guided laser ablation. Cross polarization optical coherence tomography (CP-OCT) was used to assess the initial depth of the lesions before removal and assess the volume of sound and demineralized tissue removed by the CO2 laser. With this image-guided approach, we believe we can achieve highly selective lesion removal and minimal damage to surrounding sound tissues.

One-step phosphorylated poly(amide-amine) dendrimer loaded with apigenin for simultaneous remineralization and antibacterial of dentine.

Dental caries, starting from demineralization of enamel and dentine, is closely related with acid-producing bacteria in oral cavity, for example, Streptococcus mutans. Remineralization is an efficient way to prevent the disease progression and facilitate the therapy of incipient caries. Therefore, for the purpose of effective dentine repair, remineralization and antibacterial should be combined simultaneously. However, most of the literatures only focus on one single aspect, while combing remineralization and antibacteria for dentine repair in one system is rarely reported. Here in this work, phosphoryl-terminated poly(amide-amine) dendrimers were loaded with apigenin, a water-nonsoluble drug antibacterial agains Streptococcus mutans. The apigenin-loaded dendrimers bind strongly with dentine, which further induce dentine tubules occlusion through mineralization in artificial saliva, and the release of apigenin can prevent further erosion of dentine by bacteria. Meanwhile, the phosphorylated dendrimers are easily prepared by one-step modification of poly(amide-amine) and exhibit good cytocompatibility. This strategy developed here can provide reference for the design of effective anti-caries materials.

Er,Cr:YSGG laser associated with acidulated phosphate fluoride gel (1.23% F) for prevention and control of dentin erosion progression.

To evaluate the effect of Er,Cr:YSGG laser, associated with fluoride application, on the prevention/control of dentin erosion. Dentin slabs were embedded in acrylic resin, flattened, and polished. Half of the specimens were previously eroded (10min immersion in 1% citric acid solution) and half were kept sound. The specimens (n = 10 each substrate) were randomly allocated into the experimental groups, according to the following treatments: control (no treatment); APF gel (1.23% F, 1min); Er,Cr:YSGG laser irradiation (P1: 0.25W, 20Hz, 2.8J/cm2, tip S75, beam diameter of 750μm, 1mm away from the surface); Er,Cr:YSGG laser irradiation (P2: 0.50W, 20Hz, 5.7J/cm2, tip S75, beam diameter of 750μm, 1mm away from the surface); APF gel+Er,Cr:YSGG laser P1 and; APF gel+Er,Cr:YSGG laser P2. Afterwards, the specimens underwent an erosion-remineralization cycling, consisting of a 5-min immersion into 0.3% citric acid, followed by 60-min exposure to artificial saliva. This procedure was repeated 4×/day, for 5days. Surface loss (SL, in μm) was determined by optical profilometry. Specimens from each group were analyzed by environmental scanning electron microscopy (n = 3). Data were statistically analyzed (α = 0.05). For the eroded specimens, APF gel presented the lowest SL, being different from the control. For the sound specimens, none of the groups differed from the control, except for Er,Cr:YSGGlaser P2, which presented the highest SL. When substrates were compared, only the eroded specimens of the control and APF + Er,Cr:YSGGlaser P1 Groups showed higher SL. Selective structure removal was observed for the laser-treated groups. None of the Er,Cr:YSGG laser parameters were effective in the prevention/control dentin erosion. Thelaser was also unable to enhance the protection of fluoride against dentin erosion.

Spectroscopic examination of enamel staining by coffee indicates dentin erosion by sequestration of elements

The mechanism of coffee eliciting erosion on teeth is unclear as few studies have investigated the direct effect of coffee on enamel and dentin structures. The present study identified how coffee, the most popular beverage worldwide, induces staining and erosion on teeth. We show the grade of erosion of molars and incisors in Sprague Dawley rats from two different age groups, young (four weeks) and old (six months). We quantified the concentration of metals contained in coffee by mass spectrometry (ICP-MS). To determine elemental content in enamel (i.e. superficial) and dentin (i.e. substructure), we used Laser-induced Breakdown Spectroscopy (LIBS) and X-ray fluorescence (XRF) spectroscopy, respectively. For LIBS, a significant decrease of Ca, P, and Na was observed in the young coffee group relative to age-matched controls, whereas a significant increase in Mn, Fe, and K was observed. In the old coffee group, a significant increase of Mg, Fe, and K was observed along with a decrease of Mg, Ca, P, Na, Sr and Zn. For XRF, a significant decrease of the Ca/P ratio in the coffee group was observed. Spectroscopy results were correlated with scanning electron microscopy (SEM) and histological analysis. The SEM analysis showed pores and open spaces between young and old coffee groups, respectively. Thinning of enamel layers, loss of continuity in the enamel-dentin-junction, and wide spaces in dentin tubules with coffee use was found histologically. Coffee induces decalcification of teeth that corresponds to erosion, exposing the dentin structure by reducing enamel. Coffee immersion demonstrated an intrinsic staining in dentin by metal deposition.

Highly acidic pH values of carbonated sweet drinks, fruit juices, mineral waters and unregulated fluoride levels in oral care products and drinks in India: a public health concern.

The objective of this study was to quantify and assess the concentrations of fluoride in commonly used oral care products, fruit juices, bottled waters, soft drinks, favoured bottled milk and milkshakes and to determine the pH of carbonated sweet drinks and drinks marketed in India. Various commercial brands of dentifrices, toothpowders, mouthwashes, bottled waters, sweet carbonated drinks and fruit juices were collected randomly from different outlets in Mangalore city, Karnataka, India. A fluoride ion-selective electrode was employed to estimate the fluoride concentrations. A standardised pH meter was used to detect pH in the drinks. The fluoride level in toothpastes ranged between 96 and 1397 mg/l, whereas in toothpowder the fluoride content ranged from 35 to 1380 mg/l and mouthwash fluoride concentrations varied from 6 to 228 mg/l. The fluoride level in bottled waters ranged between 0.10 and 0.12 mg/l, and that in fruit juices between 0.09 and 0.21 mg/l. Most of the carbonated sweet drinks and fruit juices had highly acidic pH values which ranged between 2.62 and 4.26. Of the wide variety of dentifrices and toothpowders available in India, most brands do not indicate the fluoride levels on their packaging or inserts. Similarly, the unregulated acidic pH values of carbonated sweet drinks are not only potentially contributing to non-carious tooth loss (enamel erosion and dentine erosion), but are also a contributing factor to the weight gain observed in Indian adolescents.

Active compounds and derivatives of camellia sinensis responding to erosive attacks on dentin

This research explored the potential of Camellia sinensis-derived teas and active compounds to be used as treatments to prevent dentin wear. Human root dentin slabs were randomly assigned to 5 groups (n = 10) as follows: distilled water (DW, control), epigallocatechin-3-gallate (EGCG), theaflavin gallate derivatives (TF), commercial green tea (GT), and commercial black tea (BT). The samples were submitted to a pellicle formation and an erosive cycling model (5x/day, demineralization using 0.01 M hydrochloric acid/60 s) followed by remineralization (human stimulated saliva/60 min) for three days. The samples were treated for 5 min using the test group solutions between the erosive cycles. Dentin changes were assessed with profilometry analysis and FT-Raman spectroscopy. The data regarding wear were analyzed by ANOVA followed by Tukey's test (p < 0.05). EGCG, TF derivatives, and both regular teas significantly suppressed erosive dentin loss (38-47%, p < 0.05). No obvious changes in the Raman spectra were detected in the specimens; however, the DW group had a minor relationship of 2880/2940 cm-1. The phenolic contents in both green and black tea and the important catechins appear to have protective effects on dentin loss.

Effect of Phosphorylated Chitosan on Dentin Erosion: An in vitro Study

The aim of this study was to evaluate the antierosive effect of phosphorylated chitosan in dentin. Bovine dentin specimens were randomly distributed into the following groups: (1) no treatment (NoTx/negative control), (2) phosphate-buffered saline solution (PBS), (3) AmF/NaF/SnCl₂ (positive control), (4) 0.5% chitosan solution (Chi), (5) 0.5% neutral phosphorylated (NP)-Chi, and (6) 0.5% alkaline phosphorylated (AP)-Chi. The specimens were submitted to de-remineralization treatment cycles for 5 days: 0.5% citric acid (2 min), remineralizing solution (30 min), and surface treatment according to assigned groups (2 min, 6×/day). The loss of dentin surface was measured by profilometry. Hardness and modulus of elasticity were measured using a nanoindenter equipped with a Berkovich diamond tip. The dentin surface was analyzed by scanning electron microscopy (SEM). The largest loss of dentin was observed in the No Tx and PBS groups (approx. 25 µm). The group treated with AmF/NaF/SnCl₂ showed less loss of dentin (67% reduction vs. NoTx and PBS), followed by the groups treated with NP-Chi and AP-Chi (33% reduction), and Chi (18% reduction). Nanohardness and modulus of elasticity were similar in the NoTx and PBS groups, with a small increase in stiffness in all other groups. SEM revealed that the experimental solution of AP-Chi had a favorable effect on maintaining the integrity of collagen fibrils. AmF/NaF/SnCl₂ showed a preserved mineralized collagen surface. Further studies are warranted to explore this nontoxic phosphorylated chitosan polymer as an effective agent in the prevention and treatment of dental erosion.

Prevention of erosive tooth wear: targeting nutritional and patient-related risks factors.

This article provides an overview of the nutritional and patient-related risk factors involved in the aetiology of erosive tooth wear (ETW) and the preventive strategies to counteract them. The first step is to diagnose clinical signs of ETW and to recognise causal factors. Low pH and high buffer capacity of foods/drinks are the major risk factors, while the calcium concentration is the main protective factor. Reduction of frequency of consumption and contact time of erosive foods/drinks with the teeth, use of straws appropriately positioned and consumption of dairy products are advisable. Oral hygiene has a role in the development of ETW, however, postponing toothbrushing is not clinically advisable. In cases of drug abuse, chronic alcoholism, GERD or bulimia, the patient must be referred to a doctor. Immediately after vomiting, patients might be advised to rinse the mouth. Saliva has an important protective role and patients with reduced salivary flow can benefit from the use of chewing gum. Recent studies have focused on improving the protective capacity of the acquired pellicle as well as on the role of protease inhibitors on dentine erosion. However, the degree of evidence for these preventive measures is low. Clinical trials are necessary before these measures can be recommended.

Effects of fluoride and epigallocatechin gallate on soft-drink-induced dental erosion of enamel and root dentin.

Fluoride and epigallocatechin gallate (EGCG) have been proven to prevent dental caries. The purpose of this study was to evaluate the effects of fluoride and EGCG on soft-drink-induced dental erosion invitro. Forty enamel and dentin specimens were prepared from extracted human teeth. The specimens were divided into 4 groups and treated separately with distilled water (as control), 0.5M sodium fluoride (NF), 400μM EGCG (EG), and a solution containing 0.5M NaF and 400μM EGCG (FG). Cyclic erosive treatment was performed according to the experimental procedures. The specimens were analyzed using laser scanning confocal microscopy, scanning electron microscopy, and a microhardness tester. The data were analyzed using ANOVA and Bonferroni's post hoc test. The significance level was set at 5%. The amount of substance loss was lower in the NF and EG groups than in the control group (p<0.05). The erosion-caused substance loss was more pronounced in the dentin than in the enamel specimens. Surface microhardness loss was lower in the NF and EG groups than in the control group (p<0.05). The diameter of the dentinal tubule was wider in the control group than in the NF and EG groups (p<0.05). No combined effects were observed in the FG group. Both fluoride and EGCG are effective in preventing soft-drink-induced erosion compared with the control group. Fluoride and EGCG may interfere with each other. The mechanisms of the anti-erosive effect need to be explored in the future.

Variation on Molecular Structure, Crystallinity, and Optical Properties of Dentin Due to Nd:YAG Laser and Fluoride Aimed at Tooth Erosion Prevention.

This in vitro study evaluated the compositional, crystalline, and morphological effects promoted by Nd:YAG laser on root dentin, and verified the effects of laser and topical acidulated phosphate fluoride application (APF-gel) on dentin erosion. 180 bovine dentin slabs were randomized into 4 groups (n = 45): G1–untreated, G2–APF-gel (1.23% F−, 4 min), G3–Nd:YAG (1064 nm, 84.9 J/cm2, 10 Hz), and G4–APF-gel application followed by Nd:YAG laser irradiation. The compositional, crystalline, and morphological effects promoted by treatments were investigated on five samples of each experimental group. The other samples were submitted to a 5-day, 10-day, or 15-day erosive and abrasive demineralization and remineralization cycling in order to create erosion lesions. The area and depth of lesions, as well as the optical attenuation coefficient, were assessed, and all data were statistically analysed (p < 0.05). Nd:YAG laser promoted the reduction of carbonate, the formation of tetracalcium phosphate, as well as the melting and recrystallization of the dentin surface. Laser significantly decreased the area and depth of erosion lesions and altered the optical attenuation coefficient when compared to untreated and APF-gel groups, but the association of APF-gel and laser did not promote an additional effect. Nd:YAG laser irradiation can be a promissory treatment to prevent dentin erosion and the abrasion process.

Synthetic Hydroxyapatite as a Biomimetic Oral Care Agent.

Human tooth enamel consists mostly of minerals, primarily hydroxyapatite, Ca10(PO4)6(OH)2, and thus synthetic hydroxyapatite can be used as a biomimetic oral care agent. This review describes the synthesis and characterization of hydroxyapatite from a chemist's perspective and provides an overview of its current use in oral care, with a focus on dentin hypersensitivity, caries, biofilm management, erosion, and enamel lesions. Reviews and original research papers published in English and German were included. The efficiency of synthetic hydroxyapatite in occluding open dentin tubules, resulting in a protection for sensitive teeth, has been well documented in a number of clinical studies. The first corresponding studies on caries, biofilm management and erosion have provided evidence for a positive effect of hydroxyapatite either as a main or synergistic agent in oral care products. However, more in situ and in vivo studies are needed due to the complexity of the oral milieu and to further clarify existing results. Due to its biocompatibility and similarity to biologically formed hydroxyapatite in natural tooth enamel, synthetic hydroxyapatite is a promising biomimetic oral care ingredient that may extend the scope of preventive dentistry.

Effect of a proanthocyanidin mouthrinse on dentin erosion

Effect of a proanthocyanidin mouthrinse on dentin erosion

Green Tea as a Treatment Modality for Dentinal Erosion

Green Tea as a Treatment Modality for Dentinal Erosion

Dentin Erosion: Method Validation and Efficacy of Fluoride Protection.

The aging population experiences more gingival recession and root exposure which increases the opportunity for dentin erosion. This study tested the use of transverse microradiography (TMR) methods to assess dentin erosion and the interaction between fluoride and citric acid on the amount of erosion in the dentin samples. In a 4 × 3 interaction experimental design, four fluoride concentrations (0.00, 25.0, 50.0, and 100.0 mg/L) and three citric acid concentrations (0.0, 0.25, and 1.00%) were combined to form 12 experimental solutions. Forty-eight dentin samples were placed in the experimental solutions for 1 and 4 h and the amount of surface lost was determined by TMR methods. The resolution of the TMR method was 0.9 μm per pixel with a 0.1% and a 5% confidence interval of ±4.2 μm. Dentin erosion increased with the concentration of citric acid and time, the erosion decreased when concentration of fluoride was increased. Effects due to fluoride and citric acid concentrations individually, and their interaction on the amount of erosion observed was statistically significant (p < 0.0001). This study found that TMR methods are appropriate and that 25.0 mg/L was the optimal fluoride concentration to protect dentin from a 1.00% citric acid challenge.