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Item Susceptibility of fluorotic enamel to dental erosion-abrasion(SciELO, 2023) Silva, Cristiane Araújo Maia; de Sousa, Frederico Barbosa; Martinez-Mier, Esperanza Angeles; Kelly, Adam Benjamin; Eckert, George J.; Hara, Anderson Takeo; Biomedical and Applied Sciences, School of DentistryDental hard tissue conditions can be of pre- or post-eruptive nature, such as enamel fluorosis and erosive tooth wear (ETW), respectively. Dental enamel fluorosis is caused by the chronic and excessive intake of fluoride during enamel development, leading to increased fluoride concentration and increased porosity. ETW has become a common clinical condition and often impairs dental function and aesthetics. This in vitro study tested the hypothesis that fluorotic enamel presents different susceptibility to dental erosion-abrasion. It consisted of a 3×3×2 factorial design, considering a) fluorosis severity: sound (TF0), mild (TF1-2), moderate (TF3-4); b) abrasive challenge: low, medium, and high; and c) erosive challenge: yes or no. A total of 144 human teeth were selected according to the three fluorosis severity levels (n=48), and subdivided into six groups (n = 8) generated by the association of the different erosive and abrasive challenges. Enamel blocks (4×4 mm) were prepared from each tooth and their natural enamel surfaces subjected to an erosion-abrasion cycling model. After cycling, the depth of the lesions in enamel was assessed by profilometry. ANOVA showed that the three-way and two-way interactions among the factors were not significant (p > 0.20). Enamel fluorosis level (p=0.638) and abrasion level (p = 0.390) had no significant effect on lesion depth. Acid exposure caused significantly more enamel surface loss than water (p < 0.001). Considering the limitations of this in vitro study, fluorosis did not affect the susceptibility of enamel to dental erosion-abrasion.Item The impact of mouth rinses on the efficacy of fluoride dentifrices in preventing enamel and dentin erosion/abrasion(Discovery Scientific Society, 2023-11) Albeshir, Ebtehal G.; Albluwi, Reem A.; Almubarak, Ibtisam K.; Alrabea, Abdulmohsen; Cook, Norman B.; Eckert, George J.; Hara, Anderson T.; Lippert, Frank; Biomedical and Applied Sciences, School of DentistryPurpose: Toothbrushing followed by is a method to maintain good oral hygiene. It is unknown to what extent mouth rinses can modulate the effect of fluoride in its ability to prevent erosion/abrasion. The aim of this in vitro study was to investigate the impact of chlorhexidine (CHX), essential oils (EO), and cetylpyridinium chloride (CPC) mouth rinses on erosive tooth wear protection afforded by conventional fluoride toothpaste. Methodology: The following experimental factors were considered: Five rinses: CHX, EO, CPC, a fluoride rinse, and water, two fluoride toothpaste: stannous fluoride (SnF2), sodium fluoride (NaF), and two models: erosion only and erosion + abrasion. Bovine enamel and dentin slabs were embedded in resin blocks (n=8). Specimens were subjected to a five-day cycling regimen consisting of twicedaily treatments, with or without abrasion, with fluoride toothpaste, followed by mouth rinse exposure. Erosion (0.3% citric acid) was performed 5×/d. Specimens were exposed to artificial saliva during remineralization periods. Surface loss (SL) was determined using non-contact profilometry. Data were analyzed using ANOVA (=0.05). Results: There was no interaction among the three factors (type of toothpaste, mouth rinse, and abrasion or not). There were no significant two-way interactions, as SL was only affected by toothpaste and mouth rinse. NaF caused less SL than SnF2 (p<0.0001) in dentin, whereas the opposite was found in enamel (p<0.0001). Erosion + abrasion caused more SL than erosion only (p<0.0001). None of the tested mouth rinses affected SL. Conclusion: Commonly used mouth rinses do not impair the erosion/abrasion protection fluoride toothpaste provides.Item The role of lead and cadmium in deciduous teeth and saliva on dental caries in children residing in Tehran, Iran(Elsevier, 2023-09) Motevasselian, Fariba; Abdi, Khosro; Ghodarati, Hoda; Shamshiri, Ahmad Reza; Lippert, Frank; Hessari, Hossein; Biomedical and Applied Sciences, School of DentistryBackground Lead (Pb) and Cadmium (Cd) are important environmental contaminants. There is no biological monitoring of exposure to these heavy metals and their potential effect on dental caries in children in Tehran, Iran, a polluted megacity. Therefore, the present study investigated the potential association between Pb and Cd levels in primary teeth and saliva and dental caries. Methods In a cross-sectional design, 211 children aged 6–11 years referred to Tehran University of Medical Sciences, School of Dentistry and residing in Tehran were examined. Pb and Cd levels of exfoliated primary teeth and stimulated saliva were determined by atomic absorption spectrophotometry (AAS). Dental caries prevalence was evaluated according to WHO criteria. Socioeconomic status, oral hygiene behavior, snacking frequency and salivary pH data were acquired as confounding factors. Frequency and percentages were reported for categorical variables, mean and standard deviation (SD) for continuous variables, and geometric mean for skewed continuous variables. A simple linear regression and Pearson correlation tests were used for statistical analyses. P-values < 0.05 were considered as significant. Result The mean (95 % confidence interval) Pb and Cd levels in teeth were 213.26 ppb (164.29–274.84) and 23.75 ppb (20.86–27.05), respectively. The mean Pb and Cd levels in saliva were 11.83 ppb (10.71–13.06) and 3.18 ppb (2.69–3.75), respectively. Furthermore, Pb and Cd in primary teeth and saliva were not associated (p > 0.05) with socioeconomic status, oral hygiene behavior and snacking frequency Conclusion This study showed no association between Pb and Cd concentrations in primary teeth and in saliva with dental caries prevalence.Item The effect of water filter pitchers on the mineral concentration of tap water(Wiley, 2025) Hazzazi, Loai Wadea; Soto-Rojas, Armando E.; Martinez-Mier, E. Angeles; Nassar, Hani M.; Eckert, George J.; Lippert, Frank; Biomedical and Applied Sciences, School of DentistryObjectives: To investigate the effect of water filter pitchers on the concentration of different minerals in tap water. Methods: Nine water filter pitchers (A-I) were chosen based on consumer preferences and Amazon reviews. Each filter was tested for its ability to modify the concentrations of fluoride, calcium, magnesium, potassium, and sodium in tap water. Tap water samples were collected before and after filtration, at various intervals (1, 5, 10, 30, 50, 75, and 100 L) during filtration, and analyzed using an ion-specific electrode (fluoride) and atomic absorption spectrometry (other minerals). Statistical analyses were conducted to compare filtered and unfiltered water mineral concentrations. Results: Water filter pitcher effect: Filters F (p < 0.001) and G (p = 0.030) decreased fluoride concentrations. All filters except I (p = 0.235) and H (p = 0.717) decreased calcium concentrations (p < 0.01). Filters E (p = 0.018), D (p = 0.014), and G (p = 0.010) decreased magnesium concentrations. Filters I (p = 0.028) and D (p = 0.009) increased potassium concentrations. Filter A (p = 0.002) increased sodium concentrations, while C (p = 0.034) decreased sodium concentrations. Effect of filter aging: All filters affected mineral concentrations over time but to varying extents. Filter G had the most pronounced effect on reducing mineral concentrations compared to all others. No filter was able to completely remove fluoride from tap water, contrary to the claims made by three manufacturers. Conclusions: The present study highlighted that water filter pitchers vary greatly in their ability to affect mineral concentrations in tap water during their use. Further research is needed to develop more effective water treatment solutions.Item Effect of hydrogel-based antibiotic intracanal medicaments on crown discoloration(Korean Academy of Conservative Dentistry, 2021-10-05) Yaghmoor, Rayan B.; Platt, Jeffrey A.; Spolnik, Kenneth J.; Chu, Tien Min Gabriel; Yassen, Ghaeth H.; Biomedical and Applied Sciences, School of DentistryObjectives: This study evaluated the effects of low and moderate concentrations of triple antibiotic paste (TAP) and double antibiotic paste (DAP) loaded into a hydrogel system on crown discoloration and explored whether application of an adhesive bonding agent prevented crown discoloration. Materials and methods: Intact human molars (n = 160) were horizontally sectioned 1 mm apical to the cementoenamel junction. The crowns were randomized into 8 experimental groups (calcium hydroxide, Ca[OH]2; 1, 10, and 1,000 mg/mL TAP and DAP; and no medicament. The pulp chambers in half of the samples were coated with an adhesive bonding agent before receiving the intracanal medicament. Color changes (ΔE) were detected by spectrophotometry after 1 day, 1 week, and 4 weeks, and after 5,000 thermal cycles, with ΔE = 3.7 as a perceptible threshold. The 1-sample t-test was used to determine the significance of color changes relative to 3.7. Analysis of variance was used to evaluate the effects of treatment, adhesive, and time on color change, and the level of significance was p < 0.05. Results: Ca(OH)2 and 1 and 10 mg/mL DAP did not cause clinically perceivable tooth discoloration. Adhesive agent use significantly decreased tooth discoloration in the 1,000 mg/mL TAP group up to 4 weeks. However, adhesive use did not significantly improve coronal discoloration after thermocycling when 1,000 mg/mL TAP was used. Conclusions: Ca(OH)2 and 1 and 10 mg/mL DAP showed no clinical discoloration. Using an adhesive significantly improved coronal discoloration up to 4 weeks with 1,000 mg/mL TAP.Item Longitudinal assessment of dental erosion-abrasion by cross-polarization optical coherence tomography in vitro(SciELO, 2023) Romero, Maria Jacinta Rosario; Bezerra, Sávio José Cardoso; Fried, Daniel; Lippert, Frank; Eckert, George Joseph; Hara, Anderson Takeo; Biomedical and Applied Sciences, School of DentistryThis study tested a novel in vitro dental erosion-abrasion model and the performance of cross-polarization optical coherence tomography (CP-OCT) in longitudinally monitoring the simulated lesions. Thirty human enamel specimens were prepared and randomized to receive three dental erosion-abrasion (EA) protocols: severe (s-EA, lemon juice/pH:2.5/4.25%w/v citric acid), moderate (m-EA, grapefruit juice/pH:3.5/1.03%w/v citric acid) and no-EA (water, control). EA challenge was performed by exposing the specimens to acidic solutions 4x/day and to brushing 2x/day with 1:3 fluoridated toothpaste slurry, for 14 days. Enamel thickness measurements were obtained using CP-OCT at baseline (D0), 7 (D7) and 14 days (D14) and micro-computed tomography (micro-CT) at D14. Enamel surface loss was measured with both CP-OCT and optical profilometry at D0, D7 and D14. Data was analyzed with repeated-measures ANOVA and Pearson's correlation (r) (α = 0.05). CP-OCT enamel thickness decreased over time in the s-EA group (D0 >D7 > D14, p < 0.001) and m-EA group (D0 > D14, p = 0.019) but did not change in the no-EA group (p = 0.30). Overall, CP-OCT and micro-CT results at D14 correlated moderately (r = 0.73). CP-OCT surface loss was highest for s-EA (p <0.001) but did not differ between moderate and no-EA (p = 0.25). Enamel surface loss with profilometry increased with severity (no-EA>m-EA>s-EA, p < 0.001). D14 surface loss was higher than D7 for both methods except for the no-EA group with profilometry. CP-OCT and profilometry had moderate overall correlation (r = 0.70). Our results revealed that the currently proposed in vitro dental erosion-abrasion model is valid and could simulate lesions of different severities over time. CP-OCT was a suitable method for monitoring the EA lesions.Item Comprehensive Evaluation of Long-Term Dentin Bond Strength, Water Sorption, Solubility, and Degree of Conversion of Self-Adhesive Resin Composites(Quintessence, 2024-09-17) Yao, Ye; Wu, Di; Cifuentes-Jimenez, Carolina Cecilia; Sano, Hidehiko; Alvarez-Lloret, Pedro; Yamauti, Monica; Tomokiyo, Atsushi; Biomedical and Applied Sciences, School of DentistryPurpose: To evaluate the long-term microtensile bond strength (µTBS) to dentin, water sorption (WSP) and solubility (WSL), and degree of conversion (DC) of self-adhesive resin composites (SACs). Materials and methods: The mid-coronal dentin of human molars was exposed, and teeth were randomly assigned to five groups according to the SACs (n = 10): 1. FIT SA F03 (FIT); 2. Experimental (EXP); 3. Fusio Liquid Dentin (FLD); 4. Vertise Flow (VER); 5. Constic (CON). The µTBS was evaluated after 24 hours (24 h) and 6 months (6 m) storage. A scanning electron microscope examined failure modes and resin-dentin interfaces. The WSP and WSL (n = 5) were evaluated following ISO 4049:2019 specifications, and DC (n = 3) was measured using Raman spectroscopy. The statistical analyses were performed accepting a significance level of p = 0.05. Results: FIT, EXP, and FLD produced significantly higher µTBS median values than VER and CON after 24 h and 6 m (p 0.05). After 6m, the µTBS median of FIT and EXP significantly decreased (p 0.05), while FLD, VER, and CON showed no significant difference (p > 0.05). FLD and CON exhibited lower WSP than FIT, EXP, and VER (p 0.05). FLD presented the lowest (p 0.05), and VER revealed the highest WSL (p 0.05). FIT and EXP showed the highest (p 0.05), and VER demonstrated the lowest DC (p 0.05). Conclusions: Following the present study's design, SACs' bonding performance and physical properties remained restricted. Therefore, the application should be considered cautiously, and further clinical trials are necessary to evaluate their long-term performance.Item Characterizing Curing Efficiency of EGCG-Encapsulated Halloysite Nanotube Modified Adhesives for Durable Dentin–Resin Interfaces(MDPI, 2024-12-24) Alhijji, Saleh; Platt, Jeffrey A.; Al-Maflehi, Nassr; Alhotan, Abdulaziz; Haider, Julfikar; Bottino, Marco C.; Windsor, L. Jack; Biomedical and Applied Sciences, School of DentistryMatrix metalloproteinase (MMP)-induced collagen degradation at the resin-dentin interface remains a significant challenge for maintaining the longevity of dental restorations. This study investigated the effects of epigallocatechin-3-gallate (EGCG), a potent MMP inhibitor, on dental adhesive curing efficiency when encapsulated in halloysite nanotubes (HNTs). EGCG-loaded HNTs were incorporated into a commercial dental adhesive (Adper Scotchbond Multi-Purpose) at 7.5% and 15% w/v concentrations. To isolate the effects of each component, the study included three control groups: unmodified adhesive (negative control), adhesive containing only HNTs, and adhesive containing only EGCG (0.16% and 0.32%, equivalent to the EGCG content in EGCG-HNT groups). Degree of conversion (DC), polymerization conversion (PC), and Vickers micro-hardness (VHN) were assessed to evaluate curing efficiency. The addition of 7.5% EGCG-encapsulated HNTs maintained curing properties similar to the control, showing no significant differences in DC (80.97% vs. 81.15%), PC (86.59% vs. 85.81%), and VHN (23.55 vs. 24.12) (p > 0.05). In contrast, direct incorporation of EGCG at 0.32% significantly decreased DC (73.59%), PC (80.63%), and VHN (20.56) values compared to both control and EGCG-HNT groups (p < 0.05). Notably, HNT encapsulation mitigated these negative effects on polymerization, even at higher EGCG concentrations. These findings demonstrate that EGCG encapsulation in HNTs can maintain the curing efficiency of dental adhesives while potentially preserving the MMP-inhibitory benefits of EGCG.Item Metformin-Loaded Nanospheres Laden Photocrosslinkable Gelatin Hydrogel for Bone Tissue Engineering(Elsevier, 2021) Qu, Liu; Dubey, Nileshkumar; Ribeiro, Juliana S.; Bordini, Ester A. F.; Ferreira, Jessica A.; Xu, Jinping; Castilho, Rogerio M.; Bottino, Marco C.; Biomedical and Applied Sciences, School of DentistryThe aim of this investigation was to engineer metformin (MF)-loaded mesoporous silica nanospheres (MSNs)-laden gelatin methacryloyl (GelMA) photocrosslinkable hydrogels and test their effects on the mechanical properties, swelling ratio, drug release, cytocompatibility, and osteogenic differentiation of stem cells from human exfoliated deciduous teeth (SHEDs). As-received and carboxylated MSNs (MSNs-COOH) were characterized by scanning and transmission electron microscopies (SEM and TEM), as well as Fourier-transform infrared spectroscopy (FTIR) prior to hydrogel modification. MF-MSNs-COOH were obtained by loading MF into MSNs at a 1:1 mass ratio. Upon MSNs-COOH laden-hydrogels fabrication, the mechanical properties, swelling ratio and MF release were evaluated. SHEDs were seeded on the hydrogels and cytocompatibility was examined. The effects of the MF-MSNs-COOH/GelMA on the osteogenic differentiation of SHEDs were measured by ALP activity, Alizarin Red assay, and Real-time PCR. Statistics were performed using one-way ANOVA (α = 0.05). Morphological (SEM and TEM) analyses of pristine and carboxylated MSNs revealed a mean particle size of 200 nm and 218 nm, respectively. Importantly, an intrinsic nanoporous structure was noticed. Incorporation of MSNs-COOH at 1.5 mg/mL in GelMA led to the highest compressive modulus and swelling ratio. The addition of MSNs-COOH (up to 3 mg/mL) in GelMA did not impact cell viability. The presence of MF in MSNs-COOH/GelMA significantly promoted cell proliferation. Significant upregulation of osteogenic-related genes (except OCN) were seen for modified (MSNs-COOH and MF-MSNs-COOH) hydrogels when compared to GelMA. Altogether, the engineered MF-MSNs-COOH/GelMA shows great promise in craniomaxillofacial applications as an injectable, cell-free and bioactive therapeutics for bone regeneration.Item Remineralisation of enamel erosive lesions by daily-use fluoride treatments: network meta-analysis of an in situ study set(Springer, 2024-12-26) Creeth, Jonathan; Smith, Gary; Franks, Billy; Hara, Anderson; Zero, Domenick; Biomedical and Applied Sciences, School of DentistryObjectives: Daily-use fluoride products are first-line protection against enamel wear from dietary-acid exposure (DAE). This study aimed to understand effects of fluoride concentration, fluoride salt, product form and ingredients in daily-use products on remineralisation and demineralisation, via network meta-analysis (NMA) of 14 studies using one well-established in-situ model. Remineralisation (surface-microhardness recovery, SHMR) after treatment, and protection against subsequent demineralisation (acid-resistance ratio, ARR) were measured. Materials and methods: Healthy participants, wearing intra-oral palatal appliances holding enamel specimens eroded with standardised DAE, used test products once. Enamel hardness was assessed (Knoop microhardness probe) pre-DAE; post-DAE; after 4 h intra-oral remineralisation; and after post-remineralisation DAE. NMA was performed using a mixed-models approach on subject-level data to estimate and compare means. Results: There was a dose-response for fluoride ion in toothpastes (0-1426ppm F; p < 0.001 for SMHR and ARR). One toothpaste (silica-based, 1150ppm F as NaF) showed a benefit for SMHR versus placebo [mean(standard error)]: 8.8%(0.6%) (33.0% vs. 24.2%; p < 0.001); for ARR: 0.27(0.03) (0.43 vs. 0.15; p < 0.001; 9 mutual studies). Use of fluoride mouthwash after fluoride toothpaste increased SMHR [2.4%(1.1%); p = 0.043; 3 studies]; the effect on ARR [0.08(0.05)] was not significant (p = 0.164). Negative effects of polyvalent metal ions and polyphosphates on SMHR (p < 0.05) were observed. Conclusions: NMA proved effective in discriminating between fluoride-based treatments in this in-situ study, highlighting the importance of fluoride ion to enamel protection and showing formulation ingredients can affect its performance. Clinical relevance: Daily-use fluoride products can protect enamel against dietary acids, but careful formulation is required for optimal performance.