Anterior provisional fixed partial dentures: A finite element analysis.

PURPOSE: The aim of this study was to analyze the stress distribution of fiber-reinforced composite provisional fixed partial denture utilizing a finite element analysis model. MATERIAL AND METHODS: Three anterior teeth were collected: upper right central, left central, and right lateral incisors. A fiber-reinforced composite strip was applied to the palatal surfaces of the teeth. Micro-computed tomographic scans were acquired of the models in order to generate three-dimensional geometrical replicas. Finite element analysis was used to assess the stress distribution of fiber-reinforced composite provisional fixed partial denture using different pontic types under static applied forces that were 100, 30, and 0 N. RESULTS: The maximum stress values were found on the unprepared natural pontic. Stress values ranged from 92.2 to 909.8, 116.4 to 646.7, and 93.8 to 393.5 MPa for composite, naturally prepared, and natural unprepared pontic, respectively. CONCLUSIONS: Using unprepared natural tooth pontic in anterior provisional fixed partial denture to replace missing central incisors is considered superior to other types in terms of stress distribution.

Shear Bond Strength and Fluoride Release of a Universal Adhesive: An In-Vitro Study on Primary Teeth.

This investigation aimed to assess the shear bond strength and fluoride-releasing capabilities of Clearfil Universal Bond Quick (Kuraray Noritake Dental Inc., Tokyo, Japan). Forty-four extracted primary molars were divided into two groups, and the enamel substrate was prepared for evaluating shear bond strength. Scotchbond (3M ESPE) and Clearfil UBQ were used to bond composite-to-enamel substrates in each group (n = 22). Shear bond strength was measured using a universal testing device and compared. Sixteen discs (6 mm diameter and 3 mm thickness) were fabricated from each Clearfil UBQ, Fuji IX, and Fuji II LC. Over the course of 30 days, each materials' fluoride release was examined and compared using ion analysis. Results revealed that Clearfil UBQ had statistically similar shear bond strength to Scotchbond. Between the three materials, Clearfil UBQ had the lowest fluoride release at baseline (0.11 ± 0.25) and the lowest cumulative fluoride release (0.12-0.27 ppm) over 30 days. Fuji IX had the highest fluoride release at baseline (19.38 ± 2.50) and cumulatively (40.87 ± 4.03 ppm), followed by Fuji II LC. We conclude that Clearfil UBQ and Scotchbond showed comparable bond strengths to the enamel. Fluoride release was seen in Clearfil UBQ in the initial two days of the 30-day period. The amount of fluoride release was significantly less than with glass ionomer cements.

Comparative evaluation of weighted mean and composite score for combining assessments.

OBJECTIVES: Approaches for combining scores have been based on weighted mean (WM) without consideration for psychometric characteristics of each individual assessments. This study evaluates consequences of WM and composite score (CS) approach. METHODS: Data from two longitudinal cohorts (n = 219) were utilized for performance in three Operative Dentistry courses as basis to compare the two score-combining methods. Four assessments (two written and two practical exams) from each course were combined using WM and CS approaches. WM scores were calculated by multiplying the score by its weight and summing across assessments. The CS approach follow a modification of the Kane and Case method, by standardizing scores, taking into account the reliability and associations between each assessment score. t-Tests and Pearson's correlation were used to evaluate the consequences of the WM and CS approaches. In addition, changes in each student's rank across WM and CS were determined. RESULTS: Combining scores using CS method produced lower scores and higher percentage failure in all courses compared to WM. Students ranks were changed significantly when CS was used with only 15% of the cohorts retained their ranks. CONCLUSIONS: CS produced a composite that is correlated with WM but still being substantively different providing meaningful and psychometrically rigorous information.

Effect of Light Curing Distance on Microhardness Profiles of Bulk-Fill Resin Composites.

Bulk-fill (BF) dental resin composites are made to be polymerized in increments of up to 5 mm rather than the 2 mm increment recommended for conventional composites. This project aimed to determine microhardness (MH) profiles of BF resin composites at different depths and varying light cure (LC) distances from the light source in an attempt to mimic varying clinical situations. Forty-eight cylindrical specimens (4 mm diameter and 6 mm height) were prepared from 3 BF composites: Tetric N-Ceram Bulk-Fill (TBF), Filtek One Bulk-Fill (FBF), and Sonic-Fill 2 (SF2). Four different distances (0, 2, 4, and 6 mm) from the LC unit were investigated. Vickers MH was measured at the top and bottom of the samples and at every 1 mm, by creating 3 indentations at each depth. The bottom-top microhardness ratio (MHR) and percentage reduction in MHR were also measured. Data was analyzed using mixed-model repeated-measure ANOVA at 0.05 significance level. The main variables effects "material, LC distance, and depth" were significant (p < 0.001). Increasing LC distance and the depth of the tested BF significantly affected Vickers MH and MHR. None of the tested BF materials had sufficient MHR at the depths of 4-6 mm. SF2 showed the least MHR reduction.

Antimicrobial properties of dental cements modified with zein-coated magnesium oxide nanoparticles.

The aim of this study was to test the antimicrobial properties of dental cements modified with magnesium oxide (MgO) nanoparticles. Zein-modified MgO nanoparticles (zMgO) in concentrations (0.0, 0.3, 0.5, and 1.0%) were mixed with dental cements (Fuji II, Rely X Temp E, Ionoglass Cem, Es Temp NE, and System P link). Eight discs were fabricated from each zMgO-cement pair for a total of 32 specimens for each cement. Characterization of the dental cements incorporating zMgO was done by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The antimicrobial properties of the mixtures were tested using direct contact and agar diffusion assays against Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, and Candida albicans. Data was analyzed using two-way analysis of variance and LSD post hoc test at 0.05 significance level. XRD spectra showed sharp peaks of zMgO indicating its high crystalline nature, while the amorphous dental cements with zMgO had broad peaks. FESEM analysis showed a uniform distribution of the zMgO nanoparticles in the cement. There were significant inhibition zone values associated with all concentrations of zMgO-cement mixtures tested compared to controls (p < 0.001) with a dose-response recorded only with Fuji II. Optical density values were significantly lower in zMgO groups compared to controls for all microorganisms. The effect was most prominent with Rely X against C. albicans and S. aureus. Dental cements containing zMgO showed significant antimicrobial properties that were dependent on the specific initial cement substrate.

Current Novel Caries Diagnostic Technologies: Restorative Dentists' Attitude and Use Preferences.

Early detection of caries lesions is key to a successful restorative dental treatment plan. The aim of this study was to investigate the preferences and attitude of graduate restorative dentistry residents (RDRs) regarding novel caries diagnostic technologies (NCDT) and to provide a brief overview of available technologies for both specialized and general dental practice. This cross-sectional study used an online questionnaire (17 questions) concerning RDRs' attitude, preferences, and insights regarding five available NCDTs. It was distributed among twenty RDRs at a local government dental school following a review session about NCDTs. Collected responses were analyzed statistically using one-way analysis of variance (ANOVA), chi-squared with Bonferroni correction, and Kruskal-Wallis tests at a 0.05 significance level. Sixty-five percent of RDRs reported an interest in NCDTs as a discussion topic and almost half of them were positive towards their use, however, sixty percent of respondents were hesitant to diagnose caries solely using NCDTs. Fiber-optic-transillumination (FOTI) systems were ranked the best overall and with regard to all the investigated criteria (p < 0.05). Chosen reasons for FOTI included price followed by ease of use. In general, high price rated as the most perceived reason for not choosing a given NCDT followed by low practical applicability. Meanwhile, ease of use followed by relevant application ranked as the main reported reasons to choose an NCDTs.

Utilizing Light Cure Units: A Concise Narrative Review.

The use of photo-curable resin composite restorations is an essential treatment modality in modern dental practice. The success and longevity of these restorations depend on achieving predictable and effective polymerization. Understanding the dynamics of the polymerization and the effect of light cure units (LCUs) on this process is paramount. The goal of this concise narrative review is to provide a simplified presentation of basic principles of composite chemistry, polymerization reactions, and photo-curing with relevant terminologies. Clinical guidelines for choosing and maintaining LCUs, as well as safety precautions and factors under the control of the clinician are listed. Finally, clinical recommendations of LCUs' usage and monitoring are included to aid practitioners in achieving predictable polymerization during the placement of direct resin composite restorations.

Effect of dentifrice slurry abrasivity and erosive challenge on simulated non-carious cervical lesions development in vitro.

PURPOSE: To investigate the effect of slurry abrasive levels and acidic challenges on the development of non-carious cervical lesions. METHODS: Ninety-six extracted upper premolars were affixed in pairs to acrylic blocks and had their root surfaces covered by acrylic resin except for 2 mm from the cemento-enamel junction. The specimens were distributed into six groups (n = 8 pairs) based on two experimental factors: (1) slurry abrasivity level [low/medium/high] and (2) citric acid challenge [yes/no]. Specimens were brushed for 5,000, 15,000, 35,000, and 65,000 strokes. Volume loss (VL) was determined based on optical profilometry scans of specimens impressions at the baseline and at subsequent brushing levels. Data were analyzed using repeated measures analysis of variance and Bonferroni pairwise comparison (α = 0.05). RESULTS: Higher VL values were associated with high-abrasivity slurries relative to low- and medium-abrasivity slurries (P < 0.001). Increasing the slurry abrasivity level increased the VL regardless of the acidic challenge, which did not have a significant effect (P = 0.184). After 65,000 strokes, significant VL was recorded in all groups relative to preceding brushing levels (P < 0.001). CONCLUSION: Higher values of time-dependent surface loss were associated with increased dentifrice slurry abrasivity, regardless of the citric acid challenge.

Artificial Caries Lesion Characteristics after Secondary Demineralization with Theobromine-Containing Protocol.

Developing artificial caries lesions with varying characteristics is needed to adequately study caries process in vitro. The objective of this study was to investigate artificial caries lesion characteristics after secondary demineralization protocol containing theobromine and fluoride. Sixty bovine enamel slabs (4 × 3 mm) were demineralized using a Carbopol-containing protocol for 6 days. A baseline area (2 × 3 mm) was protected with acid-resistant nail varnish, after which specimens were exposed for 24 h to a secondary demineralization protocol containing acetic acid plus one of four fluoride/theobromine combinations (n = 15): theobromine (50 or 200 ppm) and fluoride (0 or 1 ppm). Specimens were sectioned and analyzed using transverse microradiography for changes in mineral content, lesion depth, and surface layer mineralization. Data was analyzed using paired t-test and analysis of variance followed by Bonferroni test at 0.05 significance level. After secondary demineralization, fluoride-containing groups had significantly deeper lesions (p = 0.002 and 0.014) compared to the group with 0 ppm fluoride and 50 ppm theobromine. Mineral content and lesion depth were significantly different compared to baseline for all groups. Theobromine did not show an added effect on mineral uptake. Theobromine-containing groups exhibited particularly deep lesions with a more uniform mineral profile in the presence of fluoride.

Irradiance of Different Curing Modes of Common Light Cure Devices: An In Vitro Study.

AIM: The aim of this study was to test the irradiance values of different curing modes of commonly available light cure devices (LCDs). MATERIALS AND METHODS: An in vitro investigation was carried out to compare the irradiance output of 10 brands of LCDs available in Saudi Arabia measured using a digital radiometer. Values were recorded for three time points when applicable (0, 10, and 20s). This technique was repeated five times for each LCD. Normal, high-intensity, and soft-start modes were evaluated for all brands with the features available. Irradiance values between brands were analyzed using one-way analysis of variance followed by Bonferroni method. Changes in irradiance between different time points were analyzed using one sample t test for normal and high-intensity modes and using paired t test for soft-start mode. All comparisons were carried out at 0.05 significance level. RESULTS: The highest values were reported for Ortholux Luminous, Elipar DeepCure-S, Elipar DeepCure, and KaVo mini-LED with values above 1000 mW/cm2. All LCDs showed values above 600 mW/cm2. Three LCDs had high-intensity mode and only one device had soft-start mode. Changes over the different time points were not statistically significant exept for soft-start mode. CONCLUSION: All tested LCDs had irradiance values sufficient for adequate polymerization of resin composite. Only four of these are capable of curing bulk-fill composites.

Dental Caries Preventive Considerations: Awareness of Undergraduate Dental Students.

The aim of this study was to assess awareness and knowledge of undergraduate dental students of common caries-related preventive considerations and to highlight these factors in a concise manner to act as a guide for dental practitioners. A sample of 118 undergraduate students at a local government dental school was included. An interactive survey that contains questions related to common preventive strategies against dental caries was presented to the students. The survey contained 22 questions concerning dietary and therapeutic strategies. Students casted their votes using their mobile cellphones. The correct answer for each question was shown to the students, and further discussion was held. Data was collected, and the statistical analysis was conducted using one-sample z- and chi-squared tests at 0.05 significance level. The students answered the questions related to oral hygiene practices, xylitol, and the common knowledge regarding fluoride. The questions related to the use of chlorhexidine, dietary factors, and fluoride formulations were answered mostly incorrectly. The students seemed to grasp details of important concepts of flossing, brushing, reducing frequency of sugar exposure, and the use of fluoride products. Still, more emphasis should be given to increase students' awareness of dietary guidelines for caries prevention, since adequate knowledge of these modalities is paramount for graduating dentists.

Computer simulation and virtual reality in undergraduate operative and restorative dental education: A critical review.

The primary aim of this review was to synthesize the literature for studies investigating the use of computer simulation (CS) and virtual reality (VR) in undergraduate dental education in operative and restorative dentistry. The secondary aim was to list best practices that maximize the simulation experience in dental education. A literature review of the PubMed and ERIC databases was conducted using the search terms "Dental AND Simulator," "Dental AND Virtual reality," and "Simulation AND Dental education." Studies in English language were categorized into 1 of 5 themes: Manual dexterity and cavity preparation, light curing skills, simulation perception and experience, predictability, and simulation model development. Main practices of simulation education indicated in the McGaghie et al. critical review published in 2010 were used as a reference to identify common practices for dental simulation. Thirty nine of 579 identified abstracts met the inclusion criteria. Skill acquisition and feedback were the two most frequently investigated parameters found in the review. CS was efficient in teaching cavity preparation and light curing skills. Feedback and deliberate practice were among the best practices that should be emphasized in order to enhance the efficiency of the CS and VR simulation exercises. The use of CS is effective in teaching operative skills (such as light curing and cavity preparation) reliably; whereas, the use of VR in undergraduate curricula is debatable. To achieve the maximum benefits of the simulation exercises, emphasis must be given to the timely feedback and deliberate practice approaches.

Color Stability and Micro-Hardness of Bulk-Fill Composite Materials after Exposure to Common Beverages.

OBJECTIVES: To assess the color stability and surface microhardness of Bulk-Fill composite materials available in the Saudi Arabia market. METHODS: Five composite materials (Filtek Z350, Filtek Bulk-Fill, Tetric N-Ceram Bulk-Fill, Sonic Fill 2, and SDR) were investigated. Samples (n = 20; 10 mm in diameter and 2 mm in thickness) were fabricated using a stainless-steel mold and were immersed in tea, coffee, berry juice, and distilled water (control). Baseline (T0) shades of specimens were recorded using a spectrophotometer and after 10 (T1), 30 (T2), 60 (T3), and 90 days (T4) of immersion. Measurements were obtained against a black background and CIE L*a*b* data was used to calculate ΔE for each group. Vickers microhardness values were obtained at T0 and T4. Data was analyzed using mixed model repeated measure ANOVA at 0.05 significance level. RESULTS: Time, material, and solution effects have statistically significant effect on ΔE. Tea was the most staining solution. Z350 was associated with the highest ΔE values while SDR showed the lowest values. No other materials showed significant difference between each other. Solutions were statistically different from each other. All materials were different from each other regarding microhardness. CONCLUSION: Bulk-Fill materials showed more color stability but lower microhardness values compared to universal resin control.

Fluoride Release from Two High-Viscosity Glass Ionomers after Exposure to Fluoride Slurry and Varnish.

The effect of brushing with different fluoride slurries on the fluoride release (FR) of different high-viscosity glass ionomer cements (GICs) was investigated. Fifty-eight discs were fabricated from two high-viscosity GICs (GC Fuji IX (F9) and 3M ESPE Ketac-fil (KF)). Five specimens from each brand were used to measure Vickers microhardness and the remaining were randomly assigned to one of four groups (n = 6) based on two-factor combinations: (1) fluoride concentration in the abrasive slurry (275 or 1250 ppm fluoride as NaF) and (2) immersion in a 22,500 ppm fluoride-containing solution. Specimens were brushed for a total of 20,000 strokes over 4 days with daily FR measurement. Data were analyzed using analysis of variance and Bonferroni tests (α = 0.05). Baseline FR and microhardness values were different between the two tested material brands. Exposure to a 22,500 ppm solution was associated with higher FR but not the exposure to 1250 ppm slurries. Brushing and immersion of glass ionomer cements in a 22,500 ppm F solution led to higher FR that was more sustained for KF. Type of the glass ionomer, progressive brushing, and fluoride varnish affected FR but not the fluoride content in the abrasive slurry.

Impact of toothbrushing frequency and toothpaste fluoride/abrasivity levels on incipient artificial caries lesion abrasion.

OBJECTIVES: To investigate the interplay among brushing frequency, dentifrice slurry abrasivity, and fluoride content on the surface loss (SL) of incipient enamel caries-like lesions. METHODS: Lesions were created in 96 bovine enamel specimens (5 × 5 mm) using methylcellulose acid gel. Specimens were randomly allocated to 12 groups (n = 8), resulting from the association of three experimental factors: (1) slurry abrasive level [low: REA = 4/RDA = 69 and high: REA = 7/RDA = 208], (2) fluoride concentration [275 and 1250 ppm F as NaF], and (3) brushing frequency [1, 2 and 3× daily]. Specimens were kept in artificial saliva in between brushings and overnight. SL was determined by optical profilometry after lesion creation, 1, 3, 5, and 7 days. Data was analyzed with repeated measures ANOVA and Tukey's tests (α = 0.05). RESULTS: High abrasive slurry caused significantly more SL than low with 275 ppm (p < 0.001) but not with 1250 ppm fluoride (p = 0.34). Fluoride at 275 ppm had significantly more SL than 1250 ppm with high abrasive slurry after 7 days (p = 0.008). Brushing 1×/day had significantly less SL than 3×/day after 7 days with high abrasive slurry (p = 0.016), especially in the 275 ppm fluoride groups. CONCLUSIONS: Higher fluoride concentration increased protection against the deleterious effect of high abrasive slurry. SL was higher if brushing was performed more than twice daily especially in low fluoride groups. CLINICAL SIGNIFICANCE: Highly abrasive toothpaste formulations might cause more surface wear to incipient caries lesions, especially at higher brushing frequencies. Increasing the fluoride content may be beneficial at these circumstances.

Efficiency of light curing units in a government dental school.

The light intensity of a light-curing unit is a crucial factor that affects the clinical longevity of resin composites. This study aimed to investigate the efficiency of light-curing units in use at a local governmental dental school for curing conventional and bulk-fill resin materials. A total of 166 light-curing units at three locations were examined, and the brand, type, clinic location, diameter of curing tip, tip cleanliness (using a visual score), and the output (in mW/cm2 using a digital radiometer) were recorded. Only 23.5% of the units examined had clean tips, with the graduate student clinical area containing the highest percentage of clean tips. Further, tips with poor cleanliness score values were associated with significantly lower output intensities. A small percentage (9.4%) of units was capable of producing intensities higher than 1,200 mW/cm2 and lower than 600 mW/cm2 (7.6%). The majority of the low intensity units were located in the undergraduate student area, which also contained the highest number of units with intensities between 900 and 1,200 mW/cm2. The output of all the units in service was satisfactory for curing conventional resin composites, and most units were capable of curing bulk-fill resin materials.

Infection Control Barrier and Curing Time as Factors Affecting the Irradiance of Light-Cure Units.

OBJECTIVE: The objective of the study is to investigate the effect of infection control barrier (ICB) and curing time on irradiance of light cure units (LCUs). METHODS: Irradiance (mW/cm2) of the LCUs at a government dental school were recorded with and without ICB at 0 (T0), 10 (T10), and 20 (T20) seconds using a digital radiometer. Data were analyzed using IBM® SPSS® Statistics Version 17 for Windows software for the analysis of variance and Bonferroni methods at 0.05 significance level. RESULTS: Using ICB resulted in a statistically significant effect on the irradiance mean (P < 0.01). A significant difference existed between the four different brands of LCUs at different time intervals, irrespective of the use of ICB. At T0 and T10, the mean output of Acteon mini-light-emitting diode (LED) was significantly higher than that of either the Kerr Demi Ultra or the Kavo Polylux II. At T20, E-Morlit's mean irradiance was significantly higher than that of Kerr Demi Ultra, which in turn was significantly higher than that of the Kavo PolyLux II. The mean irradiance of the LEDs was significantly higher than that of the halogens irrespective of barrier placement and at all-time points. CONCLUSION: The ICB used in this study resulted in a statistically significant reduction in the irradiance output. No significant difference in the irradiance was found at different curing time intervals for the tested units regardless of ICB usage.

Biofilm sensitivity of seven Streptococcus mutans strains to different fluoride levels.

The effect of fluoride concentrations in dental products could be different depending on the Streptococcus mutans strain. The aim of this study was to investigate the effect of different fluoride concentrations corresponding to dental products on biofilm formation and metabolic activity of S. mutans strains. Seven S. mutans strains (UA159, A32-2, NG8, 10449, UA130, LM7, and OMZ175) were inoculated into 96-well microtiter plates and were tested with various concentrations of sodium fluoride (0.0, 1.0, 1.56, 3.13, 6.25, 12.5, 25, 50, 100, 125, 175, 225, 275, 625, 1,250, 2,250, and 5,500 ppm) for inhibition of biofilm formation and bacterial metabolic activity by recording absorbance values followed by scanning electron microscope (SEM) images. Data were analyzed by one-way analysis of variance and Tukey's tests (α = 5%). Significantly more (p≤0.05) biofilm mass in the presence of fluoride was produced by A32-2 and NG8. UA130, LM7, and OMZ175 were more sensitive to increased fluoride and demonstrated few bacterial cells and extracellular polysaccharide (EPS) production at 100 ppm in SEM images. All strains were unable to produce significant biofilm at concentrations >225 ppm. Patients with tolerantS. mutans strains would potentially benefit less from the inherent antibacterial effect of fluoride.

Effect of brushing with two different abrasives on fluoride release by high-viscosity glass ionomer cement.

The effect of brushing with two abrasive levels on the fluoride release of high-viscosity glass ionomers (GIs) was investigated. Forty-eight GI discs were fabricated and randomly assigned to one of the four groups. Treatments, performed for 30 days, included exposure to a carboxymethylcellulose (CMC) solution without fluoride (CMC-F), CMC with 275 ppm fluoride (CMC+F), CMC with fluoride plus brushing with a low abrasive slurry (relative enamel abrasivity = 4; L-ab), and CMC with fluoride plus brushing with a high abrasive slurry (relative enamel abrasivity = 7; H-ab). Fluoride release was measured after 1, 2, 3, 4, 5, 10, 15, 20, 25, and 30 days. Surface analysis was performed using optical profilometry in addition to scanning electron microscopy. Data were compared using one-way analysis of variance (α = 0.05). Fluoride release was significantly different among groups, with group H-ab showing the highest rates. Cumulative fluoride release was 10% and 30% greater in groups L-ab and H-ab than in group CMC+F. High surface roughness values were associated with H-ab as well as greater exposure of silica fillers, as observed by scanning electron microscopy. Fluoride release from conventional GIs is enhanced by brushing with high abrasive slurries.

Dentifrice fluoride and abrasivity interplay on artificial caries lesions.

Incipient caries lesions on smooth surfaces may be subjected to toothbrushing, potentially leading to remineralization and/or abrasive wear. The interplay of dentifrice abrasivity and fluoride on this process is largely unknown and was investigated on three artificially created lesions with different mineral content/distribution. 120 bovine enamel specimens were randomly allocated to 12 groups (n = 10), resulting from the association of (1) lesion type [methylcellulose acid gel (MeC); carboxymethylcellulose solution (CMC); hydroxyethylcellulose gel (HEC)], (2) slurry abrasive level [low (REA 4/ RDA 69); high (REA 7/RDA 208)], and (3) fluoride concentration [0/275 ppm (14.5 mM) F as NaF]. After lesion creation, specimens were brushed in an automated brushing machine with the test slurries (50 strokes 2×/day). Specimens were kept in artificial saliva in between brushings and overnight. Enamel surface loss (SL) was determined by optical profilometry after lesion creation, 1, 3 and 5 days. Two enamel sections (from baseline and post-brushing areas) were obtained and analyzed microradiographically. Data were analyzed by analysis of variance and Tukey's tests (α = 5%). Brushing with high-abrasive slurry caused more SL than brushing with low-abrasive slurry. For MeC and CMC lesions, fluoride had a protective effect on SL from day 3 on. Furthermore, for MeC and CMC, there was a significant mineral gain in the remaining lesions except when brushed with high-abrasive slurries and 0 ppm F. For HEC, a significant mineral gain took place when low-abrasive slurry was used with fluoride. The tested lesions responded differently to the toothbrushing procedures. Both slurry fluoride content and abrasivity directly impacted SL and mineral gain of enamel caries lesions.