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Objectives:  The purpose of the present study was to evaluate the efficacy of spiral ganglion neuron (SGN) regeneration after dental pulp stem cell (DPSC) transplantation in a rat sensorineural hearing loss (HL) model., Materials and Methods:  Sham or experimental HL was induced in adult Sprague-Dawley rats by cochlear round window surgery. An HL rat model was established with a single 10 mM ouabain intratympanic injection. After 7 days, the rats received DPSCs, stem cells from human exfoliated deciduous teeth (SHED), or culture medium in the sutural area to establish four groups: sham, HL-DPSC, HL-SHED, and HL-medium. Histological analyses were performed at 4, 7, and 10 weeks after transplantation, and the number of SGNs, specific SGN protein expression, and the function of SGNs were evaluated., Statistical Analysis:  Data were statistically by MS Excel and SPSS v.15.0. Intergroup level of significance was determined via a one-way analysis of variance and Duncan's multiple range test with 95% confidence intervals., Results:  New SGN formation was observed in the HL-DPSC and HL-SHED rat groups. The number of SGNs was significantly higher in the HL-DPSC and HL-SHED groups than in the HL-medium group over 4 to 10-week survival period. HL-DPSC rats exhibited higher SGN density compared with that in HL-SHED group, which was statistically significant at week 10. The regenerated SGNs expressed cochlear wiring regulator GATA-binding-protein 3. Moreover, the SGNs from the HL-DPSC group also exhibited a higher expression of synaptic vesicle protein and regulated action potential-dependent neurotransmitter release compared with SGNs from the HL-SHED group., Conclusions:  Our findings suggest that DPSCs and SHED repair and regenerate SGNs in rat HL model. Dental pulp stem cells represent a promising treatment strategy for restoring damage to the sensory circuits associated with deafness., Competing Interests: Dr. Chareonsri Thonabulsombat, Dr. Hathaitip Sritanaudomchai, Dr. Kutkao Vongsavan, Rattanavijit Vijitruth, and Visut Rawiwet reported All support for the present manuscript from Mahidol University and Mahidol University Faculty of Dentistry.All other authors declare no conflicts of interest related to this study., (The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/).)

Aims and Objectives: The aim of this in vitro study was to evaluate the remineralization effect of calcium glycerophosphate (CaGP) in fluoride mouth rinse on permanent enamel eroded by a soft drink., Materials and Methods: Forty sound permanent premolars were embedded in self-curing acrylic resin and immersed in Coca-Cola to create erosive lesions. The teeth were divided into four groups ( n = 10): Group I artificial saliva; Group II sodium fluoride; Group III sodium fluoride + sodium monofluorophosphate; and Group IV sodium monofluorophosphate + CaGP. The specimens in the assigned groups underwent pH cycling for ten days. The baseline, after erosion, and after remineralization surface microhardness (SMH) values were determined. The data were analyzed by one-way analysis of variance (ANOVA). The mean SMH value between groups and one-way repeated measures ANOVA for the mean SMH value within each group and Bonferroni's for multiple comparisons at a 95% confidence level were determined. The average SMH was used and calculated as the percentage recovery of SMH., Results: After being eroded by the cola soft drink, the mean SMH values in all groups were significantly decreased. After remineralization, Group I had the lowest %SMHR. The %SMHR of Groups II, III, and IV were significantly higher than Group I ( P < 0.001). However, there were no significant differences among Groups II, III, and IV ( P > 0.05)., Conclusions: Fluoride mouth rinse with and without CaGP showed similar efficacies in remineralizing eroded permanent enamel., Competing Interests: Nil., (Copyright: © 2023 Journal of International Society of Preventive and Community Dentistry.)

Objectives: Human dental pulp stem cells (DPSCs) have been used to regenerate damaged nervous tissues. However, the methods of committing DPSCs into neural stem/progenitor cells (NSPCs) or neurospheres are highly diverse, resulting in many neuronal differentiation outcomes. This study aims to validate an optimal protocol for inducing DPSCs into neurospheres and neurons., Methodology: After isolation and characterization of mesenchymal stem cell identity, DPSCs were cultured in a NSPC induction medium and culture vessels. The durations of the culture, dissociation methods, and passage numbers of DPSCs were varied., Results: Neurosphere formation requires a special surface that inhibits cell attachment. Five-days was the most appropriate duration for generating proliferative neurospheres and they strongly expressed Nestin, an NSPC marker. Neurosphere reformation after being dissociated by the Accutase enzyme was significantly higher than other methods. Passage number of DPSCs did not affect neurosphere formation, but did influence neuronal differentiation. We found that the cells expressing a neuronal marker, β-tubulin III, and exhibiting neuronal morphology were significantly higher in the early passage of the DPSCs., Conclusion: These results suggest a guideline to obtain a high efficiency of neurospheres and neuronal differentiation from DPSCs for further study and neurodegeneration therapeutics.

Background: Impacted mandibular third molar removal is one of the most commonly performed oral surgical procedures. This procedure can lead to several postoperative complications, such as trismus, facial swelling, and pain, which occur as a result of the inflammatory responses to surgery. This study compared the efficiency of preoperative injections of 4 mg versus 8 mg dexamethasone into the pterygomandibular space to reduce postoperative sequelae., Methods: This was a randomized, prospective, split-mouth, controlled study, including 52 mandibular third molar surgeries in 26 patients. Each patient was randomized to either the 4 mg or 8 mg dexamethasone injection group. Dexamethasone was injected into the pterygomandibular space after numbness from local anesthesia. Data were collected for trismus, facial swelling, visual analog scale (VAS) pain score, and the number of analgesics taken during the evaluation period. The level of significance was set at P < 0.05., Results: Statistically significant differences in postoperative facial swelling (P = 0.031, diff = 1.4 mm) and pain (P = 0.012, diff = 0.020) were found between the 8 mg and 4 mg dexamethasone groups. However, there were no significant differences between the groups for trismus and the total number of analgesics consumed (P > 0.05)., Conclusion: Compared to the 4 mg preoperative dexamethasone injection, the 8 mg preoperative dexamethasone injection into the pterygomandibular space was more effective in reducing postoperative swelling and pain following the surgical removal of the impacted mandibular third molar. However, the difference in trismus could not be evaluated clinically. Therefore, the recommendation of administering the 4 mg dexamethasone preoperative injection is optimal in the third molar surgical procedure., Competing Interests: CONFLICTS OF INTEREST: The authors declare no conflicts of interest., (Copyright © 2021 Journal of Dental Anesthesia and Pain Medicine.)

Background/purpose: Local anesthetics and anesthetic techniques affect the patterns of pulpal blood flow (PBF) and pulpal anesthesia in human teeth. This study aimed to determine PBF changes and pulpal anesthesia of intact mandibular first molars and canines after administration of 4% articaine with epinephrine 1:100,000 using inferior alveolar nerve block (IANB)., Materials and Methods: Ten healthy subjects received IANB of 4% articaine with epinephrine 1:100,000. Laser Doppler flowmetry and electrical pulp testing were combined to assess PBF changes and pulpal anesthesia of intact mandibular first molars and canines. The data were analyzed using one-way repeated-measures analysis of variance and Student-Newman-Keuls test., Results: IANB with 4% articaine and epinephrine 1:100,000 did not have any significant change in PBF for the first 20 min post injection in mandibular first molars, and for 45 min post injection in the canines ( P  > 0.05). However, a hyperemic response occurred during 25-60 min post injection in the molars, and between 60 and 75 min post injection in the canines ( P  < 0.05). Thereafter, the PBF in both teeth returned to the baseline. Onset of pulpal anesthesia was 8.60 ± 2.12 min in the molars, and 9 ± 1.94 min in the canines. Duration of pulpal anesthesia was 82.40 ± 41.56 min in the molars, and 84 ± 47.40 min in the canines., Conclusion: In case of successful IANB, 4% articaine and epinephrine 1:100,000 caused insignificant changes in PBF up to 30 min but a hyperemic response at later time points. Thereafter, the PBF returned to the baseline., Competing Interests: The authors have no conflicts of interest relevant to this article., (© 2020 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Background/purpose: The use of cavity treatments may help in the reduction of bacteria remaining in dentinal tubules after selective carious tissue removal. This study aimed to investigate the effect of selective carious tissue removal and treatment with either 35% phosphoric acid +0.12% chlorhexidine or dentine conditioner on the residual intratubular bacteria in coronal dentine of deep carious lesions., Materials and Methods: Thirty carious human molars were randomly divided into three groups; group 1: untreated carious teeth (positive control), group 2: carious teeth treated with 35% phosphoric acid and chlorhexidine disinfectant after selective carious tissue removal and group 3: carious teeth treated with dentine conditioner after selective carious tissue removal. Another six non-carious teeth was used as negative control. The presence of bacteria and depth of bacteria remaining in dentinal tubules were determined by scanning electron microscopy (SEM). Chi square test and one-way, repeated-measures analysis of variance were used for statistical analysis., Results: Using SEM, coronal dentine of group 1, 2 and 3 revealed cocci, rod and filamentous bacteria within dentinal tubules. Positive rates of bacteria detection in coronal dentine of group 1 were significant higher than those of group 2 and 3 ( P  < 0.05). The distance of bacteria remaining in the dentinal tubules in group 1, 2 and 3 were 1149.14 ± 384.44, 707.98 ± 357.19 and 869.25 ± 470.75 μm, respectively., Conclusion: Both treatment groups had similar ability to reduce the number of intratubular bacteria in coronal dentine of carious teeth, but not complete elimination., Competing Interests: The authors declare that they have no conflicts of interest relevant to this article., (© 2020 Association for Dental Sciences of the Republic of China. Publishing services by Elsevier B.V.)

Sensorineural hearing loss is a common disability found worldwide which is associated with a degeneration of spiral ganglion neurons (SGN). It is a challenge to restore SGN due to the permanent degeneration and viability of SGN is requisite for patients to receive an advantage from hearing aid devices. Human dental pulp stem cells (DPSC) and stem cells from human exfoliated deciduous teeth (SHED) are self-renewing stem cells that originate from the neural crest during development. These stem cells have a high potential for neuronal differentiation. This is primarily due to their multilineage differentiation potential and their relative ease of access. Previously, we have shown the ability of these stem cell types to differentiate into spiral ganglion neuron-like cells. In this study, we induced the cells into neural precursor cells (NPC) and cocultured with auditory brainstem slice (ABS) encompassing cochlear nucleus by the Stoppini method. We also investigated their ability to differentiate after 2 weeks and 4 weeks in coculture. Neuronal differentiation of DPSC-NPC and SHED-NPC was higher expression of specific markers to SGN, TrkB, and Gata3, compared to monoculture. The cells also highly expressed synaptic vesicle protein (SV2A) and exhibited intracellular calcium oscillations. Our findings demonstrated the possibility of using DPSCs and SHEDs as an autologous stem cell-based therapy for sensorineural hearing loss patients., (© 2020 American Association for Anatomy.)

Objectives: The aim of this study was to determine the effect of intraosseous (IO) anesthesia with 4% articaine and 1:100,000 epinephrine on pulpal blood flow (PBF) and pulpal anesthesia of mandibular first molars and canines in human subjects., Materials and Methods: Ten healthy volunteers with intact mandibular first molar and canine were given an osteocentral technique of IO injection using the Quick Sleeper 5 system and 4% articaine with 1:100,000 epinephrine at distal site of mandibular first molar. The PBF was monitored by a laser Doppler flowmeter (LDF). Pulpal anesthesia was assessed with an electric pulp tester (EPT)., Results: IO injection caused a decrease in PBF in molars from 6.31 ± 3.85 perfusion units (P.U.) before injection to 2.51 ± 2.53 P.U. 1 min after injection (P < 0.001). The percentage reduction in PBF was 60% after 1 min and PBF returned back to the baseline after 45 min. No significant reduction in PBF was observed in the canines (P = 0.212). For pulpal anesthesia in the molars, the mean onset was 2.40 ± 0.84 min and the mean duration was 38 ± 16.19 min. In the canines, there was a decrease in the sensitivity to EPT but complete pulpal anesthesia was not achieved., Conclusions: IO injection distal to mandibular first molar caused a decrease in PBF and successful pulpal anesthesia in first molar, but not in canine. Both PBF and EPT readings returned to normal, suggesting that pulpal ischemia may not occur., Clinical Relevance: IO anesthesia is safe to use as a primary technique in teeth with normal pulp.

Objective: Stem cells from pulp tissue are a promising cell-based therapy for neurodegenerative patients based on their origin in the neural crest. The aim of this study was to differentiate and evaluate the ability of human dental pulp stem cells from permanent teeth (DPSC) and stem cells from human exfoliated deciduous teeth (SHED) to differentiate into spiral ganglion neurons., Design: After isolation and characterization of mesenchymal stem cell properties, DPSC and SHED were treated with the neurotrophins brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and glial cell-derived neurotrophic factor (GDNF). The differentiation was identified by immunostaining and qRT-PCR analysis of neuronal markers and measuring intracellular calcium activity., Results: After 2 weeks of induction, morphological changes were observed in both DPSC and SHED. The differentiated cells expressed neuron-specific class III beta-tubulin, GATA binding protein 3 (GATA3) and tropomyosin receptor kinase B, protein markers of spiral ganglion neurons. These cells also showed upregulation of the genes encoding these proteins, namely GATA3 and neurotrophic receptor tyrosine kinase 2. Intracellular calcium dynamics that reflect neurotransmitter release were observed in differentiated DPSC and SHED., Conclusion: These results demonstrate that dental pulp stem cells from permanent and deciduous teeth can differentiate into spiral ganglion neuron-like cells., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Fluoride dentifrice is effective in preventive dental caries but may cause fluorosis, especially in young children. Reducing the concentration of fluoride from the regular concentration of 1,000 parts per million (ppm) to 500 ppm can reduce the risk for fluorosis but increases the risk of caries. Adding tricalcium phosphate (TCP) to the dentifrices may improve the efficacy of remineralization possibly allowing for a lower concentration of fluoride to reduce the risk of fluorosis. We studied this to inform future caries prevention efforts in children. We immersed 40 sound primary incisors into demineralizing solution (pH=4.4) for 96 hours at 37°C to create demineralized lesions. The 40 teeth were then divided into 4 groups of 10 teeth each. Group A: control (treated with deionized water only); Group B: treated with fluoride dentifrice at a concentration of 1,000 ppm; Group C: treated with fluoride dentifrice at a concentration of 500 ppm and 500 ppm TCP, and Group D: treated with fluoride dentifrice at a concentration of 1,000 ppm and 500 ppm TCP. The teeth were each subjected to 7 days of pH-cycling and the studied dentifrice was applied for one minute, 3 times daily during the 7 day period. After the 7 day period the teeth were each sectioned and examined with polarized light microscopy. The depths of demineralized areas were measured using Image-Pro plus software. A pair t-test was used to compare lesion depths before and after dentifrice treatment. Differences in mean lesion depths within each group were analyzed using the One-way ANOVA and LSD tests; a 95% confidence intervals were calculated. The mean lesion depths in all the groups before dentifrice treatment were not significantly different (p=0.143). The mean demineralized lesion depths after dentifrice treatment were significantly different by group (p=0.00). The mean demineralized lesion depth in Group A significantly deeper than the other groups (p=0.00). Group D had the shallowest depth, significantly shallower than the other groups (p=0.006). There was no significant difference in the mean demineralized lesion depth between Groups B and C (p=0.478). The mean demineralized lesion depth changed significantly after dentifrice treatment in all the groups (p=0.00). Group A was significantly deeper (p=0.00) and groups B, C and D were all significantly shallow. Group D had the greatest reduction in mean demineralized lesion depth (p<0.05). The 1,000 ppm fluoride plus TCP dentifrice gave superior remineralization than the 500 ppm fluoride plus TCP and the 1,000 ppm fluoride dentifrice. The 500 ppm fluoride plus TCP gave the same remineralizing effect as the 1,000 ppm fluoride dentifrice. TCP enhances remineralization on primary enamel when added to fluoride dentifrice. Our results show if TCP is added to fluoride dentifrice a lower concentration of fluoride is needed to provide the same benefit as fluoride dentifrice with a higher concentration of fluoride, reducing the risk of fluorosis in children.

Objectives: Fluoride toothpaste has been extensively used to prevent dental caries. However, the risk of fluorosis is concerning, especially in young children. Calcium phosphate has been an effective remineralizing agent and is present in commercial dental products, with no risk of fluorosis to users. This in vitro study aimed to compare the effects of different calcium phosphate compounds and fluoride-containing dentifrices on artificial caries in primary teeth., Materials and Methods: Fifty sound primary incisors were coated with nail varnish, leaving two 1 mm 2 windows on the labial surface before immersion in demineralizing solution for 96 hours to produce artificial enamel lesions. Subsequently, one window from each tooth was coated with nail varnish, and all 50 teeth were divided into five groups ( n = 10); group A - deionized water; group B - casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (Tooth Mousse); group C - 500 ppm F (Colgate Spiderman ® ); group D - nonfluoridated toothpaste with triple calcium phosphate (Pureen ® ); and group E - tricalcium phosphate (TCP). Polarized light microscopy and Image-Pro ® Plus software were used to evaluate lesions., Results: After a 7-day pH-cycle, mean lesion depths in groups A, B, C, D, and E had increased by 57.52 ± 10.66%, 33.28 ± 10.16%, 17.04 ± 4.76%, 32.51 ± 8.99%, and 21.76 ± 8.15%, respectively. All data were processed by the Statistical Package for the Social Sciences (version 16.0) software package. Comparison of percentage changes using one-way analysis of variance and Fisher's least squares difference tests at a 95% level of confidence demonstrated that group A was significantly different from the other groups ( P < 0.001). Lesions in groups B and D had a significant lesion progression when compared with groups C and E., Conclusions: All toothpastes in this study had the potential to delay the demineralization progression of artificial enamel caries in primary teeth. The fluoride 500 ppm and TCP toothpastes were equal in the deceleration of enamel caries progression and better than CPP-ACP paste and TCP toothpaste., Competing Interests: There are no conflicts of interest.

A range of dental varnishes containing several calcium and phosphate compounds in addition to fluoride to promote remineralization have recently been commercialized. However, the fluoride varnish in the presence of calcium and phosphate can react to form relative poorly soluble phases and its bioavailability. Most of previous studies have focused on fluoride release over a short period. The purpose of this in vitro study was to evaluate the fluoride release from different fluoride varnishes on primary teeth during 3 months. Twenty-five sound primary incisors were randomly divided into five groups: Group A-control group (no treatment), Group B - 5% sodium fluoride varnish (5%NaF)(Duraphat®), Group C-5% sodium fluoride plus tricalcium phosphate varnish (5%NaF+TCP)(ClinproTM White), Group D- 5% sodium fluoride plus amorphous calcium phosphate varnish (5%NaF+ACP)(Enamel Pro®), and Group E-5% sodium fluoride plus tricalcium phosphate varnish (5%NaF+TCP)(Mahidol). The samples were then immersed in artificial saliva at room temperature until used. The concentration of fluoride released was measured with F-ion-specific electrode at 2, 4, 8, 12, 24, and 48 hours and then weekly for three months. To analyze the results, we used the one-way ANOVA and Tukey’s multiple comparison tests at a 95% level of confidence. Group E had the greatest initial fluoride release within the first 24 hours and Group B had the lowest initial release fluoride of the treatment groups. Group B had a slower rate of decline in fluoride release over time than the other treatment groups. By 3 months, the varnishes with the highest to the lowest release of fluoride were Group B=C>E>D>A. All the treatment samples released more fluoride than the control group. Duraphat®(5%NaF) and Clinprotm(5%NaF+TCP) had the highest release of fluoride at 3-month evaluation. The TCP fluoride varnish released more fluoride than the ACP fluoride varnish by 3 months.

Dental caries are a major public health problem worldwide. The aim of this study was to compare the effects of children's follow-on instant powdered cow's milk formula, buffalo milk formula and a chicken-based formula on microhardness of bovine enamel with artificial caries-like lesions. Forty bovine teeth were each placed in acrylic blocks and the enamel surfaces were polished to create flat 5 x 5 millimeter surfaces. The teeth surfaces were then demineralized using 0.1M lactic acid (pH 4.5) to achieve an enamel microhardness of 35-65 Vickers Hardness Numbers (VHN). All specimens were then randomly allocated into one of 4 groups (n=10/group). For remineralization, each group was soaked in a different kind of milk formula for 2 hours at 37°C except group 1 which was a negative control (artificial saliva) group. Group 2 was soaked in Murrah™ buffalo milk formula (a positive control ), group 3 in S-26-Promil-Gold™ (cow's milk formula) and group 4 in a chicken-based formula (Siriraj Hospital, Mahidol University). The microhardness of the specimens was then measured again. Data were analyzed using a one-way ANOVA and paired t-test with a 95% confidence interval. After exposure to the formula, the mean VHN for each study group was significantly higher (paired t-test, p < 0.05) except for group 1 (p = 0.345). The mean VHN for the the Murrah™ buffalo milk formula, the chicken-based formula and the S-26-Promil-Gold™ formula group were not significantly different from each other (one-way ANOVA, p > 0.05). In conclusion, S-26-Promil-Gold™ follow-on cow milk formula, Murrah™ buffalo milk formula and the chicken-based formula all increased bovine enamel microhardness after soaking for 2 hours.

Objective: To determine the effectiveness of the iontophoretic delivery of lignocaine with epinephrine through carious dentine for pain control during cavity preparation., Design: The experiments were carried out on 56 carious molars that required class I restorations in 42 subjects (aged 15-20 years). The overhanging enamel and soft caries were removed then the sensitivity of the exposed dentine was tested with drilling, probing and air blast stimuli. The subject indicated the intensity of any pain produced by marking a visual analogue scale (VAS). The cavity was then filled with 20% w/v lidocaine with 0.1% w/v epinephrine and a 200 μA iontophoretic current applied for 2 min after which the sensitivity of the dentine was re-tested. If the dentine was not anaesthetized, the treatment and testing were repeated up to 6 times., Results: The total duration (min) of iontophoresis required to anaesthetize the dentine was: 2 in 7 teeth, 4 in 17 teeth, 6 in 14 teeth, 8 in 4 teeth, and 10 in 7 teeth. The remaining 7 teeth were not anaesthetized even after 14 min of iontophoresis., Conclusions: The iontophoretic delivery of lignocaine with epinephrine anaesthetized dentine for cavity preparation in 49 of 56 (87.5%) of carious molars., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objective: To determine the effects of the iontophoretic application of lignocaine and epinephrine to exposed dentine on the sensitivity of the dentine in human subjects., Design: The experiments were carried out on 13 healthy premolars (13 subjects) that were scheduled for extraction. Dentine was exposed at the tip of the buccal cusp by cutting a cavity which was etched with 35% phosphoric acid. The sensitivity of the dentine was tested with probing and air blast stimuli. The subject indicated the intensity of any pain produced with a score of 0-100. In 7 teeth, the cavity was filled with a solution containing 20% (w/v) lignocaine HCl and 0.1% (w/v) epinephrine HCl, and an iontophoretic current of 120 μA was passed for 90s. The sensitivity of the dentine was tested before and immediately after the treatment and then at 10 min. intervals for 40 min. Pulpal blood flow was recorded at each stage. Control experiments were carried out on 6 teeth using a solution containing only the epinephrine., Results: The lignocaine plus epinephrine solution completely blocked the pain produced by both forms of stimulus immediately, and this continued for at least 40 min. It also produced an immediate fall in pulpal blood flow that also lasted for at least 40 min. The epinephrine solution had the same effect on pulpal blood flow but no effect on dentine sensitivity., Conclusions: The topical application of 20% lignocaine and 0.1% epinephrine, with an iontophoretic current of 120μA for 90s, will anaesthetize exposed, normal, dentine., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The purpose of the present study was to evaluate the effect of fluoride mouthrinse containing tricalcium phosphate on microhardness of demineralized primary enamel. Thirty-six sound primary incisors were immersed in a demineralizing solution (pH 4.4) for 96 hours at 37 degrees C to create artificial caries-like lesions. After artificial caries formation, the specimens were randomly divided into 3 groups (with 12 specimens in each group): Group A: deionized water; Group B: 0.05% NaF plus 20 ppm tricalcium phosphate mouthrinse and Group C: 0.05% NaF mouthrinse. All the specimens were immersed for 1 minute at 37 degrees C three times per day for 7 days in the respective mouthrinse among pH cycling. The surface microhardness was examined using a Vickers hardness tester (100 grams for 15 seconds) at baseline, before and after the pH-cycling procedure. Data were analyzed using one-way ANOVA and Tukey's multiple comparison tests with a significance level of 0.05. After treatment, Group Ahad a significantly lower surface microhardness value than the other two groups (p=0.000); however, there was no significant difference between Groups B and C (p=0.728). We concluded fluoride mouthrinse containing tricalcium phosphate and fluoride mouthrinse have similar remineralizing effects on microhardness of demineralized primary teeth.

The objective of this study was to assess the effectiveness of oral hygiene education kits (OHE kits) and 0.05% sodium fluoride mouth rinse among visually impaired students (VIS) in Bangkok, Thailand. Seventy-five VIS aged 10-12 years were included in the study and examined for plaque index (PI), gingival index (GI) and mutans streptococci (MS) salivary levels at baseline and after intervention. The subjects were then randomly divided into three groups. Group 1 received OHE kits and 0.05% NaF mouth rinse and brushing instructions. Group 2 received only the OHE kits and brushing instructions. Group 3 (control) received only brushing instructions. PI, GI and MS levels, were reassessed 3 months after intervention. Pre- and post-intervention evaluation data were compared with the Wilcoxon match-pairs test (p < 0.05). The post-intervention results were significantly better in all 3 groups compared to the pre-intervention result (p < 0.01). Group 1 had the lowest PI and the PI was significantly lower than the other groups (p < 0.05). The GI was significantly lower in Group 1 than Group 3, Group 2 than Group 3 (p < 0.05). MS level was reduced significantly in group 1 and 2 compared to control (p < 0.001, p = 0.038, respectively). All groups showed the reduction of PI, GI, and MS levels. However, students who either received OHE kits with or without sodium fluoride mouthrinse showed significantly lower gingival index and lower number of MS than control group.

The aim of this study was to evaluate the effect of fluoride mouthrinse containing tricalcium phosphate (TCP) on remineralization of primary teeth enamel lesions compared with fluoride mouthrinse alone to determine if the addition of TCP gives additional benefit. Thirty-six sound primary incisors were immersed in a demineralizing solution (pH 4.4) for 96 hours at 37°C to create demineralized lesions. After artificial caries formation, the specimens were randomly assigned to one of three groups (n = 12): Group A: deionized water; Group B: 0.05% sodium fluoride (NaF) plus 20 ppm tricalcium phosphate mouthrinse and Group C: 0.05% sodium fluoride (NaF) only mouthrinse. A pH-cycling process was carried out for 7 days at 37°C. During pH-cycing, all the specimens were immersed for 1 minute; 3 times a day, in the respective mouthrinse. The specimens were then evaluated by polarized light microscopy with the computerized Image Pro Plus program. Data were analyzed using paired-t, one-way ANOVA and Tukey's multiple comparison tests at a 95% level of confidence. The depth of the lesions were significantly different between pre- and post-treatment for all groups (p = 0.00). The lesion depth in the Group A (control) increased by 102% (±15), in Group B by 34% (±12) and Group C by 36% (±9). The lesion depths differed significantly between the control (Group A) and treatment groups (Group B,C) (p < 0.05). Group A had a significantly greater increase in lesion depth compared to the other groups. There was no significant difference in the percent change in lesion depths between Groups B and C. We concluded that the fluoride mouthrinse containing tricalcium phosphate provides no additional benefit over the mouthrinse containing fluoride alone.

This study was conducted to evaluate the effect of fluoride varnishes containing different calcium phosphate sources on demineralization of initial primary enamel lesions. Forty-eight sound primary incisors were completely coated with nail varnish except for two 1 x 1 mm windows before being placed in demineralizing solution for 4 days. After demineralization, one of the windows in each tooth was coated with nail varnish. The teeth were randomly divided into four groups (A to D; n = 12), and then the other (exposed) window was treated with: Group A: deionized water, Group B: Duraphat® fluoride varnish, Group C: Clinpro™ White varnish and Group D: Enamel Pro® varnish. The pH-cycling regimen was carried out consisting of demineralization (6 hours) and remineralization (18 hours) for 7 days. Polarized light microscopy was used to evaluate the lesion depth initially and then after a seven-day pH cycle. Lesion depth was measured using a computerized method with the Image-Pro® Plus Program. The pair t-test was used to compare lesion depths before and after treatment. Differences in mean lesion depths among the groups were compared with the one-way ANOVA and Tukey's multiple comparison tests with 95% confidence intervals. The lesion depths had a significant difference between before and after treatment of the all groups. There was a significant increase in lesion depth in Group A compared to the other groups. No significant differences were seen among Groups B, C and D, containing fluoride and the different calcium phosphate sources in inhibiting progression of initial primary enamel lesions.

The aim of this study was to evaluate the combined effect of xylitol and fluoride in varnish on bovine tooth surface microhardness. Thirty caries-free bovine teeth were sectioned and embedded in self-cured acrylic resin and the buccal enamel surfaces were ground flat. Each tooth was then placed in demineralization solution for 40 hours. After demineralization, the teeth were randomly divided into 3 equal groups: group 1 was the control group (no treatment); group 2 was treated with fluoride varnish (Duraphat); group 3 was treated with a xylitol and fluoride varnish (Flor-Opal). All the specimens were then subjected to pH-cycling for 7 days, consisting of demineralization for 6 hours and remineralization for 18 hours repeated daily for five days followed by remineralization for 2 days. Surface microhardness was checked in each tooth at baseline, after demineralization and after pH-cycling. The results were recorded and the data were analyzed with the one-way ANOVA and Tukey tests. A p-value < 0.05 was considered significant. The mean surface microhardness values of the teeth treated with the fluoride varnish and the fluoride with xylitol varnish were not significantly different from each other and showed significantly better remineralization than control group. The fluoride and xylitol varnish combination was beneficial for preventing enamel demineralization but no better than in fluoride varnish alone in vitro. Adding xylitol to fluoride tooth varnish does not appear to give any significant benefit in vitro.

The aim of this study was to evaluate the effect of fluoride varnishes containing tri-calcium phosphate on remineralization of primary enamel lesions. Forty-eight sound primary incisors were coated with nail varnish, leaving two 1 x 1 mm windows before being placed in a demineralizing solution for four days. After demineralization, all the specimens were coated with nail varnish over one of the windows and were randomly assigned to one of four groups: Group A: deionized water; Group B: Duraphat Fluoride Varnish; Group C: Clinpro White Varnish; Group D: TCP-fluoride varnish. Polarized light microscopy was used to evaluate initial lesion depth and after a 7-day pH cycle. Lesion depth was measured using a computerized method with the Image-Pro Plus Program. The differences in mean lesion depths were compared among the groups using the One-Way ANOVA and Tukey's multiple comparison tests at a 95% confidence interval. Group A had a significant increase in lesion depth compared to the other groups. No significant differences were found among Groups B, C and D. We concluded fluoride varnishes containing tri-calcium phosphate inhibit progression of initial primary enamel lesions, and the brands tested were not significantly different from each other in efficacy.

Objective: To determine the effect of topical applications of 50% (w/v) lignocaine HCl on the sensitivity of human dentine., Design: The experiments were carried out on 12 premolars scheduled for extraction as part of orthodontic treatment in nine subjects (ages: 16-29 years). Dentine was exposed by cutting a cavity at the tip of the buccal cusp of each tooth, and etched with 35% phosphoric acid. The sensitivity of the exposed dentine to probing and air-blast stimuli was assessed before and after applying either 50% (w/v) lignocaine HCl solution or distilled water to the exposed dentine for 10min. Changes in the sensitivity of the dentine were monitored for up to 160min. The subject indicated the intensity of any pain produced by marking a 100mm visual analogue scale (VAS)., Results: Before treatment, both forms of stimulus evoked pain in all the teeth. The median VAS score with probing was 40mm and, with air-blast stimulation, 30mm. 50% lignocaine HCl produced a progressive fall in these scores and after 30min there was no response to either probing or air-blast stimulation. The responses started to return 30-160min after the lignocaine had been washed off. Water had no effect., Conclusions: Lignocaine will diffuse into exposed dentine and block the pain evoked by probing and air-blast stimuli provided that a sufficiently steep diffusion gradient is created. A topical application of a 50% (w/v) solution of lignocaine HCl for 10min will anaesthetise dentine within 30min., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Continuous consumption of soft drinks is the main cause of potential oral health problems, including dental caries and erosion. The purpose of this study was to compare the effect of three different types of soft drinks on the release of calcium from the enamel surface of teeth. Forty bovine teeth were selected for the experiment. They were divided into four groups (n=10/group): Group 1 (Coke), Group 2 (Pepsi), Group 3 (Sprite), and Group 4 (distilled water, the control). The pH of each beverage was measured using a pH meter. The release of calcium ions was measured using an atomic absorption spectrophotometer at baseline, 15, 30, and 60 minutes. The results were assessed by analysis of variance and then by the Tukey test (p< 0.05). Coke, with a pH of 2.39, was the most acidic among the soft drinks. Coke, Pepsi, and Sprite showed no significant mean differences in the calcium released, but there was a significant mean difference of these soft drinks with distilled water at 60 minutes. We concluded that prolonged exposure to soft drinks could lead to significant enamel loss.

The purpose of this in vitro study was to evaluate microleakage of two fluoride-releasing sealants in saliva contaminated and non-contaminated conditions. Twenty-four human third molars were randomly assigned to two groups: saliva contaminated and saliva non-contaminated teeth. In the contaminated group, the teeth were contaminated with 0.02 ml artificial saliva for 20 seconds and blowed dry afterward. Each group was divided into two subgroups: Group A, a fluoride-releasing resin sealant marketed as Clinpro and Group B, a glass-ionomer sealant marketed as Fuji VII. After sealant application, all the teeth were thermocycled for 2,000 cycles and coated with nail varnish 1.0 mm from the sealed areas. The teeth were stained with 2% methylene blue dye for 24 hours and sectioned in the bucco-lingual direction. Dye penetration (microleakage) was examined with a 25x polarized light microscope and measured by a computerized-calculated method. Data were compared with the Mann-Whitney U test at significance level of p<0.05. A comparison of the two types of sealant revealed microleakage of the glass-ionomer sealant was present but there was no significant difference between the saliva contaminated and saliva non-contaminated teeth. Microleakage of the fluoride-releasing resin sealant was present and was greater among the saliva-contaminated teeth than the saliva non-contaminated teeth. The glass-ionomer sealant had significantly greater microleakage than the fluoride-relasing resin-based sealant in both the saliva-contaminated and saliva non-contaminated teeth.

We determined the effectiveness of soy milk with calcium for prevention of enamel erosion caused by chlorinated water. Thirty-six bovine teeth without wear or caries, sized 8 x 10 mm, were placed in resin acrylic blocks. All specimens had an initial enamel microhardness of 270-320 VHN and were randomly allocated into 3 groups (n = 12/group): control (not treated), casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) tooth mousse and soy milk with calcium. We applied the CPP-ACP for 5 minutes or soaked the teeth in soy milk with calcium for 20 minutes. Then, all the specimens were soaked in chlorinated water (pH 5.0) at room temperature for 96 hours following by 30 minutes in artificial saliva and then the microhardness of each tooth was re-determined. The data were analyzed statistically using the one-way ANOVA test and the paired t-test. The group with the least reduction in microhardness was the CPP-ACP treated group, followed by the control group and then the soy milk with calcium treated group. The enamel microhardness value after exposure to chlorinated water in the soy milk with calcium group was not significantly different from the control group (p > 0.05). The CPP-ACP treated group was significantly different from the other 2 groups (p < 0.05). Soy milk with calcium gave no protection against dental erosions caused by chlorinated water.

The aim of this in vitro study was to compare the remineralization potential of dental products containing calcium on human enamel softened by soft drinks. Fifty sound human premolar teeth were randomly divided into 5 treatment groups (n=10): artificial saliva, 1,000 ppm fluoride toothpaste, CPP-ACP paste, CPP-ACP with 900 ppm fluoride paste and tricalcium phosphate with 950 ppm fluoride paste. All specimens were immersed in cola soft drink and artificial saliva for 10 cycles of 5 seconds each; this procedure was repeated twice at six-hour intervals. All specimens were remineralized by treatment with the dental products mentioned above for 5 minutes and kept in artificial saliva at 37 degrees C for 6 hours. The surface microhardness of the enamel was measured with a Vickers hardness tester (100 grams, 15 seconds) at baseline, after erosion and after remineralization. Comparison of the mean microhardness numbers within groups was made by one-way repeated measures ANOVA and between groups with the one-way ANOVA with a level of significance of p<0.05. The mean surface microhardness in all groups decreased significantly after being eroded by the soft drink and increased after treatment. After remineralization treament, the mean surface microhardness of the artificial saliva group was significantly less than the other groups. The CPP-ACP paste, CPP-ACP with 900 ppm fluoride paste and tricalcium phosphate with 950 ppm fluoride paste treatments all increased the hardness of the teeth in vitro.

The objective of this study was to assess the effect of five different dental products on surface microhardness of enamel exposed to chlorinated water in vitro. Sixty human sound premolar teeth, extracted for orthodontic reasons, were used and randomly divided into 6 groups (10 specimens each group: artificial saliva, 1,000 ppm fluoride toothpaste, CPP-ACP paste, CPP-ACP with 900 ppm fluoride paste, CPP toothpaste and tricalcium phosphate with 950 ppm fluoride paste. All specimens were immersed in chlorinated water at pH 5 for 24 hours and then remineralized by coating with a dental product from each group for 5 minutes and kept in artificial saliva at 37 degrees C for 6 hours. The surface microhardness of the enamel was measured with a Vickers hardness tester at baseline, after erosion by chlorinated water and after remineralization. Comparisons of the mean microhardness within each group were made a one-way repeated measures ANOVA and between groups using a one-way ANOVA and an LSD test at p < 0.05. The mean surface microhardness in all groups decreased significantly after eroding with chlorinated water and increased after remineralization. After remineralization, the mean surface microhardness of the artificial saliva group was significantly less than the other groups. Five different dental products (1,000 ppm fluoride toothpaste, CPP-ACP paste, CPP-ACP with 900 ppm fluoride paste, CPP toothpaste and tricalcium phosphate with 950 ppm fluoride paste) increased the hardness in vitro of eroded enamel caused by chlorinated water.

The purpose of this in vitro study was to compare the shear bond strength of different types of sealant to non-contaminated and saliva-contaminated enamel. The buccal surfaces of 60 sound permanent third molars were individually embedded in self-curing acrylic resin and wet ground with 1,000-grit silicone carbide paper to obtain a flat enamel surface. The specimens were randomly assigned to one of three groups: 1) non-fluoride-releasing resin sealant (Concise), 2) fluoride-releasing resin sealant (Clinpro), 3) glass-ionomer sealant (Fuji VII). Each group was divided into 2 subgroups (n = 10): non-contaminated and saliva contaminated with 0.02 ml of fresh human saliva for 20 seconds and then blowed dried prior to sealant placement. All samples were thermocycled 2,000 cycles. The specimens were tested using an Instron running at a crosshead speed of 0.05 mm/min. Stereomicroscope examinations were carried out to evaluate failure sites of the sealants. Data were analyzed with one-way ANOVA and the Turkey test at a siginificance level of p < 0.05. Comparison of the different types of sealant revealed the shear bond strength of the glass-ionomer sealant was the same for the non-contaminated and saliva-contaminated subgroups. The shear bond strength was lower in both the fluoride and non-fluoride releasing resin-based sealant groups contaminated with saliva than in the fluoride and non-fluoride releasing resin-based sealant groups not contaminated with saliva. Comparison of the different types of sealant also revealed the shear bond strength of the glass-ionomer sealant had a significantly lower shear bond strength than the fluoride and non-fluoride releasing resin-based sealant groups for both the non-contaminated and saliva-contaminated subgroups. The fluoride and non-fluoride releasing resin-based sealant groups were not significantly different from each other. The modes of failure were mostly mixed with the glass-ionomer sealant in both the non-contaminated and saliva-contaminated subgroups of this sealant. The resin-based sealant groups (both fluoride and non-fluoride releasing) had cohesive/mixed failure in the non-contaminated and adhesive/mixed failure in the saliva-contaminated subgroups. In conclusion, saliva-contamiantion did not affect the shear bond strength of glass-ionomer sealant but the glass-ionomer sealant had the lowest shear bond strength.