Browsing by Subject "Dental erosion"

Now showing 1 - 5 of 5
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    Cross-Polarization Optical Coherence Tomographic Assessment of In situ Simulated Erosive Tooth Wear
    (Wiley, 2021) Romero, Maria Jacinta Rosario H.; Bezerra, Savio J.C.; Fried, Daniel; Yang, Vincent; Lippert, Frank; Eckert, George J.; Zero, Domenick T.; Hara, Anderson Takeo; Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    This clinical study tested cross-polarization optical coherence tomography (CP-OCT) monitoring of erosive tooth wear (ETW). Twenty participants completed a 14-day/arm, 3-arm crossover study simulating different ETW severities. Participants received two enamel specimens (per arm) and were randomized to: severe (s-ETW, lemon juice/pH:2.5/4.25%wt/vol citric acid), moderate (m-ETW, grapefruit juice/pH:3.5/1.03%wt/vol citric acid), and non-ETW (water). Enamel thickness was measured with CP-OCT (day[D] 0, 7, 14) and micro-computed tomography (μ-CT; D14). Enamel surface loss was determined with CP-OCT and optical profilometry (OP; D7, D14). CP-OCT showed higher enamel surface loss for D14 than D7 for m-ETW (P = .009) and s-ETW (P = .040) and differentiated severity at D14 (s-ETW > non-ETW, P = .027). OP was able to differentiate surface loss between days (D7 < D14, P < .001) for m-ETW and s-ETW, and ETW severity effect after 7 and 14 days (non-ETW < m-ETW < s-ETW, P < .001). At D14, CP-OCT and μ-CT were positively correlated (r = .87, ICC = .62). CP-OCT showed potential as a tool for clinical ETW monitoring.
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    Effects of a sodium fluoride- and phytate-containing dentifrice on remineralisation of enamel erosive lesions—an in situ randomised clinical study
    (Springer, 2018-02-08) Creeth, Jonathan E.; Parkinson, Charles R.; Burnett, Gary R.; Sanyal, Susmita; Lippert, Frank; Zero, Domenick T.; Hara, Anderson T.; Cariology, Operative Dentistry and Dental Public Health, School of Dentistry
    ObjectiveThe objective of this work was to evaluate effects of a dentifrice containing sodium fluoride (1150 ppm F) and the organic polyphosphate phytate (0.85% w/w of the hexa-sodium salt) on in situ remineralisation of early enamel erosive lesions and resistance to subsequent demineralisation.Materials and methodsSubjects (n = 62) wore palatal appliances holding eight bovine enamel specimens with pre-formed erosive lesions. They brushed their natural teeth with the phytate test dentifrice (TD); a positive control dentifrice (PC, 1150 ppm fluoride as NaF); a reference dentifrice (RD, disodium pyrophosphate + 1100 ppm fluoride as NaF) or a negative control dentifrice (NC, fluoride-free) in a randomised, double-blind, crossover design. Specimens were removed at 2, 4 and 8 h post-brushing and exposed to an ex vivo acid challenge. Surface microhardness (Knoop) was measured at each stage. The primary efficacy variable was relative erosion resistance (RER); other variables included the surface microhardness recovery (SMHR), acid resistance ratio (ARR) and enamel fluoride uptake (EFU).ResultsAfter 4 h, the results for RER, ARR and EFU were in the order PC > TD = RD > NC with PC > TD = RD = NC for SMHR. Results at 2 and 8 h were generally consistent with the 4 h data. Mineralisation progressed over time. Dentifrices were generally well-tolerated.ConclusionsIn this in situ model, addition of phytate or pyrophosphate to a fluoride dentifrice inhibited the remineralising effect of fluoride. Both formulations still delivered fluoride to the enamel and inhibited demineralisation, albeit to a lesser extent than a polyphosphate-free dentifrice.Clinical relevanceAddition of phytate or pyrophosphate to a fluoride dentifrice may reduce its net anti-erosive properties.
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    Fluorotic Enamel Susceptibility to Dental Erosion and Fluoride Treatment
    (Ribeirão Preto Dental Foundation, 2023) Silva, Cristiane Araújo Maia; de Sousa, Frederico Barbosa; Martinez-Mier, Esperanza Angele; Vieira, Basílio Rodrigues; do Nascimento, Johnatan Meireles; Hara, Anderson Takeo; Dental Public Health and Dental Informatics, School of Dentistry
    The purpose of this in vitro study was to test the hypothesis that fluoride treatment can prevent dental erosion on fluorotic enamel of different severities. It followed a 3×2 factorial design, considering a) fluorosis severity: sound (TF0, Thylstrup-Fejerskov Index), mild (TF1-2), moderate (TF3-4); and b) fluoride treatment: 0 (negative control) and 1150ppmF. Human molars with the three fluorosis severities (n=16, each) were selected and randomly assigned to the two fluoride treatments (n=8). Enamel blocks (4×4mm) were prepared from each tooth and subjected to a dental erosion cycling model, for 10 days. The daily cycling protocol consisted of erosive challenges (1% citric acid, pH 2.4), interspersed by periods of immersion in artificial saliva, and three 2-minute treatments with either 0 or 1150ppm F. The enamel volume loss (mm3) was calculated by subtracting values obtained by microtomography before and after cycling. Two-Way ANOVA showed no significant interaction between fluorosis severity and fluoride treatment (p=0.691), and no significant effect for either fluorosis severity (TF0 mean±standard-deviation: 13.5(10-2±0.42(10-2, TF1-2: 1.50(10-2±0.52(10-2, TF3-4: 1.24(10-2±0.52(10-2, p=0.416) or treatment (0ppmF: 1.49(10-2±0.53(10-2; 1150ppmF: 1.21(10-2±0.42(10-2; p=0.093), when evaluated independently. Considering the limitations of this in vitro study, the presence and severity of fluorosis in enamel do not appear to affect its susceptibility to dental erosion. Fluoride treatment was not effective in preventing the development of dental erosion in both sound and fluorotic enamel substrates under our experimental conditions.
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    Interaction between toothpaste abrasivity and toothbrush filament stiffness on the development of erosive-abrasive lesions
    (2015) Arrageg, Mona; Chu, Tien-Mien; Kelton, Stewart; Cook, Norman; Lippert, Frank; Hara, Anderson T.
    Background: Toothpaste abrasivity is considered the major contributor in toothbrushing abrasive wear, while toothbrush stiffness can be considered a secondary factor that may modify the abrasivity of toothpaste. Objectives: To investigate the longitudinal enamel and dentin surface loss caused by the interaction between the abrasives in toothpaste and toothbrush filament stiffness. Study Hypothesis: The amount of enamel and dentin loss depends on the abrasivity of the toothpaste and the filament stiffness of toothbrush. Materials and Methods: The following experimental factors were considered: abrasive suspension, at two levels (L-low: Z113 and H-high: Z103); and toothbrushes at three levels determined by bristle stiffness (soft, medium, and hard) generating 6 testing groups (n = 8). Slabs of bovine enamel and dentin were cut, embedded in acrylic resin, and polished. UPVC tapes were placed on the surface of the specimens, leaving an area of 1 × 4 mm exposed in the center of the each enamel slab. Specimens (n = 8) were subjected to 5 d of erosion/abrasion cycling: erosion (5min, 4×/d, 0.3% citric acid, pH 3.75), abrasion (15 s, 2×/d, 45 strokes each, 150-g load, automated brushing machine), fluoride treatment (15 s with abrasion and 45 s without abrasion; 275 ppm F as NaF in abrasive slurry) with exposure to artificial saliva between erosion and abrasion (1h) and all other times (overnight). Surface loss (SL, in micrometers) was determined by optical profilometry, after the third and fifth days of cycling. Data were analyzed using three-way ANOVA (alpha = 0.05). For enamel, only cycling time was found to affect surface loss with 5 d > 3 d. Overall, there was little SL (mean range: 0.76 µm to 1.85 µm). For dentin (mean SL range: 1.87 µm to 5.91 µm), significantly higher SL was found for 5 d vs. 3 d, with particularly large differences for hard toothbrush high abrasive, and medium toothbrush/low abrasive. Hard toothbrush resulted in significantly higher SL than medium toothbrush for high abrasive after 5 d, with no other significant stiffness differences. High abrasive had significantly higher SL than low abrasive overall with strong effects for all combinations, except medium stiffness after 5 d. In conclusion, the interplay between abrasivity and filament stiffness appears to be more relevant for dentin than enamel.
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    Three-Dimensional Surface Texture Characterization of In Situ Simulated Erosive Tooth Wear
    (Sage, 2021) Hara, A.T.; Elkington-Stauss, D.; Ungar, P.S.; Lippert, F.; Eckert, G.J.; Zero, D.T.; Biostatistics, School of Public Health
    This in situ erosive tooth wear (ETW) study tested enamel 3-dimensional (3D) surface texture outcomes for the detection and differentiation of ETW lesions simulated in clinically relevant conditions. Twenty participants enrolled in this 3-arm crossover intraoral ETW simulation and wore their own partial denture for 14 d holding 2 human enamel specimens (per arm). In each arm, participants were assigned to 1 of 3 different dental erosion protocols: severe (lemon juice/pH 2.5), moderate (grapefruit juice/pH 3.5), and no erosion (bottled drinking water, control). Enamel specimens were evaluated by white-light scanning confocal profilometry for 3D surface texture and surface loss (ETW model validation). Individual point clouds were analyzed using standard dental microwear texture characterization protocols for surface roughness and anisotropy. Fractal complexity (Asfc), texture aspect ratio (Str), and arithmetical mean height (Sa) values were generated at baseline, 7 d, and 14 d. Data were analyzed by analysis of variance models suitable for the crossover design with repeated measurements, and correlation coefficients were used to examine the relationship between outcomes. Asfc and Sa differentiated ETW severity (no erosion < moderate < severe, P < 0.001) at days 7 and 14. Asfc and Sa were lower at baseline compared to days 7 and 14 (P < 0.001) for moderate and severe challenges. Asfc increased from day 7 to 14 (P = 0.042) for the severe challenge. For Str, ETW severity did not have a significant effect overall (P = 0.15). Asfc and Sa were highly positively correlated (r = 0.89, P < 0.001), while Asfc and Sa were not correlated overall with Str (r < 0.1, P ≥ 0.25). Enamel surface loss increased with ETW severity (no erosion < moderate < severe, P < 0.001) at days 7 and 14, validating the ETW simulation model. Complexity (Asfc) and roughness (Sa) outcomes were able to detect and differentiate ETW levels, with Asfc being able to monitor the progression of severe lesions. No clear characterization of ETW lesions could be provided by the anisotropy (Str) parameter.