Recharge and increase in hardness of GIC with CPP-ACP/F

ObjectiveTo assess the effect of CPP-ACP/F recharging on ion release and hardness of GIC Fuji-Triage (VII) and Fuji-Triage-EP (VII-EP) containing CPP-ACP/F.MethodsCPP-ACP distribution in Fuji-Triage-EP was determined using immunofluorescence. Thirty blocks of Fuji-Triage and Fuji-Triage-EP with the same surface area were placed individually in 5 mL of 50 mM lactic acid (pH 5) for three days. Every 12 h ten Fuji-Triage and ten Fuji-Triage-EP blocks were treated with 2 mL of either MI Paste Plus (CPP-ACP/F) solution (1 g paste + 4 mL water), Placebo MI paste solution (no CPP-ACP/F), or distilled water for 2 min. After each 2 min treatment the blocks were rinsed with distilled water and placed back into the acid. Calcium, inorganic phosphate and fluoride levels in the acid solution were measured using atomic absorption spectrophotometry, colorimetry and ion specific electrode respectively. Vickers surface hardness of the GIC was also determined. Data were analysed using a two-sample t-test and one-way ANOVA with a Bonferroni-Holm correction for multiple comparisons.ResultsCPP-ACP was distributed throughout Fuji-Triage-EP. Significantly (p < 0.001) higher calcium, inorganic phosphate and fluoride ion release and greater surface hardness (acid resistance) was observed in both GIC’s treated with the CPP-ACP/F paste. Fuji-Triage-EP released higher ion levels and exhibited greater surface hardness (acid resistance) than Fuji-Triage.SignificanceTopical application of CPP-ACP/F paste to GIC Fuji-Triage-EP recharged ion release and increased surface hardness (acid resistance) which may help improve properties and resistance to degradation as well as improve ion release for caries control.     

Histologic characterization of regenerated tissues after pulp revascularization of immature dog teeth with apical periodontitis using tri-antibiotic paste and platelet-rich plasma

IntroductionThis study evaluates histologically the efficacy of 4 revascularization protocols in necrotic-infected immature dog teeth with apical periodontitis (AP).MethodsForty double-rooted immature premolar teeth from 4 female Beagle dogs aged 5 months were used. Four teeth were left untouched as negative controls; the other 36 teeth were infected to develop pulp necrosis and AP. Four teeth were left untreated and assigned to the positive control group. The last 28 teeth were randomly assigned into four experimental groups of 8 teeth, each one treated with a different treatment protocol: A1, sodium hypochlorite (SH) + blood clot (BC); A2, SH + platelet-rich plasma (PRP); B1, SH + modified tri-antibiotic paste (mTAP) + BC; B2, SH + mTAP + PRP. The animals were sacrificed, histologic sections were prepared and three parameters were assessed: (1) presence or absence of new hard tissue on the internal root dentinal walls, (2) presence or absence of continued apical closure, and (3) presence or absence of vital tissue within the canal space.ResultsSignificant differences (p < 0.05) between the four experimental groups were evident in the percentage of teeth showing histological apical closure (34.5%) and vital tissue within the canal space (68.8%). Group B2 showed the maximal improvement in the three variables assessed (p < 0.05). Group A1 showed the minimum percentages in the three parameters assessed (p < 0.05).ConclusionsThese results suggest that an intracanal dressing of mTAP, and the use of PRP as scaffold, improves the success rate of the revascularization procedure.     

Sodium fluoride effect on erosion–abrasion under hyposalivatory simulating conditions

ObjectivesTo investigate the effect of fluoride (0, 275 and 1250 ppm F; NaF) in combination with normal and low salivary flow rates on enamel surface loss and fluoride uptake using an erosion–remineralization–abrasion cycling model.DesignEnamel specimens were randomly assigned to 6 experimental groups (n = 8). Specimens were individually placed in custom made devices, creating a sealed chamber on the enamel surface, connected to a peristaltic pump. Citric acid was injected into the chamber for 2 min followed by artificial saliva at 0.5 (normal flow) or 0.05 (low flow) ml/min, for 60 min. This cycle was repeated 4×/day, for 5 days. Toothbrushing with abrasive suspensions containing fluoride was performed for 2 min (15 s of actual brushing) 2×/day. Surface loss was measured by optical profilometry. KOH-soluble fluoride and enamel fluoride uptake were determined after the cycling phase. Data were analysed by two-way ANOVA.ResultsNo significant interactions between fluoride concentration and salivary flow were observed for any tested variable. Low caused more surface loss than normal flow rate (p < 0.01). At both flow rates, surface loss for 0 was higher than for 275, which did not differ from 1250 ppm F. KOH-soluble and structurally-bound enamel fluoride uptake were significantly different between fluoride concentrations with 1250 > 275 > 0 ppm F (p < 0.01).ConclusionsSodium fluoride reduced enamel erosion/abrasion, although no additional protection was provided by the higher concentration. Higher erosion progression was observed in low salivary flow rates. Fluoride was not able to compensate for the differences in surface loss between flow rates.     

An evaluation of microleakage of various glass ionomer based restorative materials in deciduous and permanent teeth: An in vitro study

AimTo evaluate the microleakage of recently available glass ionomer based restorative materials (GC Fuji IX GP, GC Fuji VII, and Dyract) and compare their microleakage with the previously existing glass ionomer restorative materials (GC Fuji II LC) in primary and permanent teeth.MethodOne hundred and fifty (75 + 75) non-carious deciduous and permanent teeth were restored with glass ionomer based restorative materials after making class I cavities. Samples were subjected to thermocycling after storing in distilled water for 24 h. Two coats of nail polish were applied 1 mm short of restorative margins and samples sectioned buccolingually after storing in methylene blue dye for 24 h. Microleakage was assessed using stereomicroscope.ResultSignificant differences (P < 0.05) were found when inter group comparisons were done. Except when GC Fuji VII (Group III) was compared with GC Fuji II LC (Group II) and Dyract (Group IV), non-significant differences (P > 0.05) were observed. It was found that there was no statistically significant difference when the means of microleakage of primary teeth were compared with those of permanent teeth.ConclusionsGC Fuji IX GP showed maximum microleakage and GC Fuji VII showed least microleakage.     

Promotion of enamel caries remineralization by an amelogenin-derived peptide in a rat model

ObjectiveAn amelogenin-derived peptide has been shown to promote remineralization of demineralized enamel in an in vitro model of initial caries induced by pH cycling. The present study examines whether the peptide exerts similar effects within the complex oral environment in vivo.DesignSpecific pathogen-free Sprague-Dawley rats (n = 36) were infected with Streptococcus mutans, given ad libitum access to Diet 2000 and drinking water supplemented with sucrose (10%, w/v), and then randomly divided into three groups treated with 25 μM peptide solution, 1 g/L NaF or deionized water. Molar teeth were swabbed twice daily with the respective solutions for 24 days. Then animals were killed, their jaws were removed and caries lesions were analyzed using the quantitative light-induced fluorescence-digital (QLF-D) technique to measure changes in mineral content. To verify QLF-D results, caries were scored for lesion depth and size using the Keyes method, and analyzed using polarized light microscopy (PLM).ResultsMineral gain was significantly higher in teeth treated with peptide or NaF than in teeth treated with water (p < 0.05), based on the QLF-D results (ΔF and ΔQ). Incidence of smooth-surface and sulcal caries based on Keyes scores was similar in rats treated with peptide or NaF, and significantly lower in these groups than in rats treated with water (p < 0.05). Lesions on teeth treated with peptide or NaF were shallower, based on PLM. No significant differences were observed between molar enamel caries treated with peptide or NaF.ConclusionsThis amelogenin-derived peptide can promote remineralization in a rat caries model, indicating strong potential for clinical use.     

Effect of proanthocyanidin on ultrastructure and mineralization of dentine collagen

ObjectiveProanthocyanidin (PA) is a natural collagen cross-linker that has been used in dentine matrix biomodification for reparative and preventive therapies. This study evaluated the ultrastructure of collagen after its interaction with PA. Furthermore, the mineralization of PA-biomodified collagen matrix was observed.MethodsTen freshly extracted sound human molars were sectioned into 0.5 mm × 1.7 mm × 7 mm beams for ultrastructural evaluation of PA and dentine matrix under Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). Specimens for TEM were completely demineralized and divided into three groups according to PA treatments: deionized water, 2% PA and 6.5% PA. The specimens were fixed, dehydrated, sectioned and examined using TEM. Specimens for FESEM were lightly conditioned with EDTA and similarly divided into the three groups for observation using FESEM. Type I collagen from calf skin was used to analyse the mineral interaction after treatment with 6.5% PA. Formvar- and carbon-coated 400-mesh Ni grids (EMS, Hatfiels, PA, USA) were placed over a 2 mg/mL collagen solution prepared from calf skin-derived Type I collagen to achieve self-assembly of collagen fibrils. Grids were treated with 6.5% PA and divided into two groups. One group was floated over a remineralization solution containing 20 mM HEPES, 2.25 mM CaCl₂-2H₂O, 1.35 mM KH₂PO4, 3.08 mM NaN3 and 130 mM KCl and the other group was over a CPP-ACP solution (Tooth mousse 1:100 dilution with deionized water). The floating samples were kept in a 37 °C and 100% humidity chamber. Grids were taken out at selected time durations (24 h, 48 h and 72 h for mineralization solution/24 h for CPP-ACP) and observed under TEM without staining. Selected area electron diffractions (SAEDs) were performed at 110 kV.ResultsFollowing treatment of demineralized dentine collagen matrix with PA, the size and number of interfibrillar spaces were reduced. The collagen fibrils aggregated together with a reduction in porosity. A characteristic banding pattern of collagen fibrils was observed under TEM. Treatment of PA-biomodified collagen fibrils with remineralization solution increased mineral aggregation along its long axis, when compared to the control group. Furthermore, treatment of PA-biomodified collagen fibrils with CPP-ACP solution enhanced mineral uptake and deposition as well as initiated apatite formation within 24 h.ConclusionProanthocyanidin alters the ultrastructure of demineralized dentine collagen matrix. The PA-biomodified collagen matrix promotes remineralization.     

Comparison of the remineralization potential of CPP-ACP and CPP-ACP with 900 ppm fluoride on eroded human enamel: An in situ study

Objective

The aim of this in situ study was to compare the remineralization potential of pastes containing CPP-ACP and CPP-ACP with 900 ppm fluoride on human enamel softened by a cola drink.

Design

Forty-five enamel specimens obtained from human third molar teeth were eroded in a cola drink for 8 min and then attached to intra-oral devices worn by five volunteers. The specimens were subjected to three different in situ remineralization protocols using: (1) CPP-ACP (Group I), (2) CPP-ACP with 900 ppm fluoride (Group II), and (3) saliva (Group III, control). Vickers microhardness measurements were obtained at baseline followed by demineralization and remineralization stages.

Results

The CPP-ACP, CPP-ACP with 900 ppm fluoride and saliva controls resulted in 46.24%, 64.25% and 2.98% increase in post-erosion microhardness values, respectively. One-way ANOVA revealed statistically significant differences in the mean microhardness values between pastes containing CPP-ACP and CPP-ACP with 900 ppm fluoride.

Conclusions

Both CPP-ACP and CPP-ACP with 900 ppm fluoride substantially remineralized the softened enamel, with the CPP-ACP and fluoride combination showing higher remineralization potential than CPP-ACP. This study confirmed the synergistic effect of fluoride with CPP-ACP on remineralization of eroded enamel.     

Effects of layering techniques on the micro-tensile bond strength to dentin in resin composite restorations

ObjectivesThe purpose of this work was to investigate the effects of layering techniques in resin composite restorations on the micro-tensile bond strength to the dentin of the occlusal cavity.MethodsHuman premolars were extracted and randomly divided into four groups. The occlusal enamel was then removed to expose a flat superficial dentin surface. Cavities 3.5 mm long and 3.5 mm wide were prepared to a depth 3 mm below the dentin surface. The adhesive Single Bond was applied according to the manufacturer's instructions. The teeth were then restored with Z100 resin composite as follows: Group 1 was restored in horizontal increments (three layers). Groups 2 and 3 were restored in different oblique increments (three layers). Group 4 was restored in oblique increments (four layers). After 24 h storage at 37 °C in water, all the teeth were sectioned to obtain bar-shaped specimens with a bonded surface area of approximately 0.9 mm × 0.9 mm. Dentin micro-tensile bond strength was measured at a crosshead speed of 0.5 mm/min. The results obtained were statistically analyzed using one-way ANOVA and SNK test at a significance level of P = 0.05. All fractures were then observed under a scanning electron microscope (SEM).ResultsThe results showed that there is a significant difference between the strength of the micro-tensile bonds to the dentin of occlusal cavities depending on which of the four layering restorative techniques was used (P < 0.01). SEM observation showed that failure patterns were most evidently interfacial cohesive failure.SignificanceLayering techniques in resin composite restorations affected the micro-tensile bond strength between the resin composite and the dentin. But the outcomes related to only Single Bond, as the same using other adhesives might have different outcomes.     

Impact of glycemic control on oral health status in type 2 diabetes individuals and its association with salivary and plasma levels of chromogranin A

ObjectiveTo evaluate the effect of glycemic control status in type 2 diabetes mellitus (T2DM) individuals on clinical oral health indicators and to compare the concentrations of plasma and salivary chromogranin A (CHGA) among nondiabetic subjects and T2DM patients, exploring their associations.DesignIn this cross-sectional study, 32 patients with controlled T2DM, 31 with poorly controlled T2DM and 37 nondiabetic subjects underwent a clinical and periodontal examination. CHGA concentrations were determined in saliva and plasma with ELISA.ResultsPoorly controlled T2DM group exhibited significantly higher mean buffering capacity, plaque index and bleeding on probing than other groups (P < 0.05). No difference was found to DMFT (decayed, missed and filled teeth) index between groups. Sites with clinical attachment loss (CAL) of 4 and 5–6 mm were significantly higher in both diabetic groups compared to control group (P < 0.05). Poorly controlled T2DM group had significantly higher sites with CAL ≥ 7 mm than other groups (P = 0.001). Significantly higher plasma and salivary CHGA levels were found in T2DM groups (P < 0.05). In both diabetic groups, probing depths 5–6 mm and CAL 5–6 mm were associated with higher salivary CHGA concentration (P < 0.05).ConclusionsThe findings revealed that T2DM patients were more prone to periodontal tissue damage than to caries risk. The results also provide some evidence that the degree of attachment loss deteriorates significantly with poor glycemic control in T2DM (CAL ≥ 7 mm). Moreover, the results suggest that high concentrations of salivary CHGA are associated with worse periodontal parameters and T2DM, and this could be related to the pathogenesis of both diseases.     

Novel fluoride rechargeable dental composites containing MgAl and CaAl layered double hydroxide (LDH)

ObjectiveThis study aims to incorporate 2:1 MgAl and 2:1 CaAl layered double hydroxides (LDHs) in experimental dental-composites to render them fluoride rechargeable. The effect of LDH on fluoride absorption and release, and their physico-mechanical properties are investigated.Methods2:1 CaAl and 2:1 MgAl LDH-composite discs prepared with 0, 10 and 30 wt% LDH were charged with fluoride (48 h) and transferred to deionized water (DW)/artificial saliva (AS). Fluoride release/re-release was measured every 24 h (ion-selective electrodes) with DW/AS replaced daily, and samples re-charged (5 min) with fluoride every 2 days. Five absorption-release cycles were conducted over 10 days. CaAl and MgAl LDH rod-shaped specimens (dry and hydrated; 0, 10 and 30 wt%) were studied for flexural strength and modulus. CaAl and MgAl LDH-composite discs (0, 10, 30 and 45 wt% LDH) were prepared to study water uptake (over 7 weeks), water desorption (3 weeks), diffusion coefficients, solubility and cation release (ICP-OES).ResultsCaAl LDH and MgAl LDH-composites significantly increased the amount of fluoride released in both media (P < 0.05). In AS, the mean release after every recharge was greater for MgAl LDH-composites compared to CaAl LDH-composites (P < 0.05). After every recharge, the fluoride release was greater than the previous release cycle (P < 0.05) for all LDH-composites. Physico-mechanical properties of the LDH-composites demonstrated similar values to those reported in literature. The solubility and cation release showed a linear increase with LDH loading.SignificanceLDH-composites repeatedly absorbed/released fluoride and maintained desired physico-mechanical properties. A sustained low-level fluoride release with LDH-composites could lead to a potential breakthrough in preventing early stage carious-lesions.     

Evaluation of remineralizing potential of hydroxyapatite,phosphopeptide-amorphous calcium phospahate and fluoride dentifrices using SEM/EDX analysis: A randomized controlled in-vitro study

AimThe aim of this study is to evaluate remineralization efficiency of hydroxyapatite (HA) containing dentifrices comparing to phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride (F) containing dentifrices using scanning electron microscope (SEM) and energy dispersive spectrometry (SEM/EDX).Material and methods3 × 3 mm² areas on the buccal surfaces of extracted primary second molars were divided vertically into 3 sections as demineralization, control and remineralization surfaces. Control surfaces (1/3 middle) coated without any application. 1/3 left and right surfaces were subjected to demineralization solution. After this application 1/3 right surfaces were coated as demineralization surfaces. Then teeth were randomly separated in 3 groups (n = 10): group HA (Natural toothpaste, Splat®, Russia); Group CPP-ACP (MI Paste ONE®, GC, U.S.); group F (Oral-B® Kids, Oral-B, Germany). 1/3 right surfaces were brushed with dentifrices twice a day for one week with pH cycle. Coatings were removed. Surface evaluations were conducted by SEM and EDX. Mann Whitney U and Kruskal Wallis tests were used for statistical analysis.ResultsBoth atomic (at%) and weight (wt%) percentages of P values were statistically significant for F group in remineralization surfaces comparing to demineralization surfaces. Ca at%, P at% and P wt% values were statistically significant for CPP-ACP group in remineralization surfaces. P at% and P wt% values for F group were higher in remineralization surfaces compared to all.ConclusionRemineralization was observed in all groups. Most homogeneous surface features were seen in group CPP-ACP.     

In vitro dentine remineralization with a potential salivary phosphoprotein homologue

ObjectiveAdvantages of introducing a salivary phosphoprotein homologue under standardized in vitro conditions to simulate the mineral-stabilizing properties of saliva have been proposed. This study longitudinally investigates the effects of casein, incorporated as a potential salivary phosphoprotein homologue in artificial saliva (AS) solutions with/without fluoride (F) on in vitro dentine lesion remineralization.DesignThin sections of bovine root dentine were demineralized and allocated randomly into 6 groups (n = 18) having equivalent mineral loss (ΔZ) after transverse microradiography (TMR). The specimens were remineralized using AS solutions containing casein 0 μg/ml, F 0 ppm (C₀–F₀); casein 0 μg/ml, F 1 ppm (C₀–F₁); casein 10 μg/ml, F 0 ppm (C₁₀–F₀); casein 10 μg/ml, F 1 ppm (C₁₀–F₁); casein 100 μg/ml, F 0 ppm (C₁₀₀–F₀) or casein 100 μg/ml, F 1 ppm (C₁₀₀–F₁) for 28 days with TMR taken every 7 days.ResultsSurface mineral precipitation, evident in group C₀–F_1, was apparently inhibited in groups with casein incorporation. Repeated measures ANOVA with Bonferroni correction revealed higher ΔZ for non-F and non-casein groups than for their counterparts (p < 0.001). Subsequent multiple comparisons showed that mineral gain was higher (p < 0.001) with 10 μg/ml casein than with 100 μg/ml when F was present in the earlier stages of remineralization, with both groups achieving almost complete remineralization after 28 days.ConclusionCasein is a potential salivary phosphoprotein homologue that could be employed for in vitro dentine remineralization studies. Concentration related effects may be clinically significant and thus must be further examined.     

Assessment of gingival biotype and facial hard/soft tissue dimensions in the maxillary anterior teeth region using cone beam computed tomography

ObjectiveThis study sought to assess the relationship between facial gingival and bone dimensions in maxillary anterior teeth region using cone beam computed tomography (CBCT).DesignThis study assessed 621 maxillary anterior teeth in 144 patients. In the sagittal plane, facial bone thickness (BT) and gingival thickness (GT) were measured at the crestal level and at 2, 4 and 6 mm apical to the cementoenamel junction (CEJ). The dentogingival complex (DGC) dimensions and the distance from the CEJ to bone crest were also measured on CBCT scans. To determine the gingival biotype, GT at 2 mm apical to the gingival margin was measured and GT <1.5 mm was categorized as thin while GT ≥1.5 mm was categorized as thick. The data were analyzed using SPSS version 21 via repeated measures ANOVA and the Cochrane’s Q, chi-square and independent samples t-tests.ResultsThe BT around the maxillary central and lateral incisors and canine teeth at 4 and 6 mm apical to the CEJ was significantly different in thick and thin gingival biotypes (P < 0.05). The mean GT at 2 and 4 mm apical to the CEJ was significantly different around central and lateral incisors (P < 0.05). Thickness of crestal bone was significantly different between the two gingival biotypes around central and lateral incisors (P < 0.05).ConclusionThe two gingival biotypes had significantly different mean BT; different biotypes and their relationship to BT varied around anterior maxillary teeth.     

Acoustic emission analysis of the effect of simulated pulpal pressure and cavity type on the tooth–composite interfacial de-bonding

ObjectiveThe aim of this study was to evaluate the influence of in vitro pulpal pressure and cavity type on the tooth–composite bonding interface by means of acoustic emission (AE) analysis.MethodsClasses I and II cavities on extracted third molars were prepared and assigned to four groups of seven teeth each: (1) direct composite restoration without simulated pulpal pressure (SPP) in class I cavity, (2) direct composite restoration with SPP in class I cavity, (3) direct composite restoration without SPP in class II cavity, (4) direct composite restoration with SPP in class II cavity. The teeth were restored with Filtek Z250 composite and Adper Scotchbond Multi-Purpose adhesive system (3M ESPE, St. Paul, MN, USA). AE events were recorded for 2000 s during light-curing. Groups 2 and 4 were subjected to 20 cm H₂O hydrostatic pressure throughout the procedures. The data were analyzed with two-way ANOVA. After the AE test, teeth were sectioned longitudinally in mesio-distal direction, the tooth–composite interface was examined using SEM.ResultsSPP in Groups 2 (4.57 ± 1.40) and 4 (3.43 ± 1.13) yielded significantly higher AE events number than those of Groups 1 (3.43 ± 1.51) and 3 (1.71 ± 0.95) where the SPP was not applied (p < 0.05). The number of AE events of class I cavity in Groups 1 and 2 were significantly higher than those of class II cavity in Groups 3 and 4 (p < 0.05). SEM examination showed that all groups had intact enamel–composite interface, while micro-gaps were observed at the dentin–composite interface, mainly at the pulpal floor of the cavity. The class I cavities with SPP in Group 2 showed wider gaps more frequently than class II cavities without SPP in Group 3.SignificanceThe SPP and class I cavity with high C-factor triggered more AE events, confirming its negative impact on the bonding interface.     

Effect of three fluoride agents on remineralization and fluoride uptake on enamel lesion

This study is to compare the fluoride uptake of three fluoride agents and the effect of remineralization on artificial enamel lesions. Eight human third molars were all divided into four slabs. The slabs were randomly assigned to the following four groups: group A (9,040 ppm F, APF gel), group B (968 ppm F, SnF₂ home gel), group C (22,600 ppm F, fluoride varnish, FV) and a control group. After 72-hour demineralizing and 10-day pH-cycling period with the application of corresponding fluorides. The distribution of fluoride and mineral change was analyzed with EPMA and CMR respectively. There was a significant increase in the amount of F uptake after the application of the three fluoride agents compared to the control group. Group A showed an extremely greater F uptake compared to group C and B. The amount of F uptake from group C was greater than that of group B. The three tested groups showed signs of significantly greater amounts of remineralization as compared to the control group. Remineralization of group C was detected to be the greatest, followed by group A and group B, but there was no significant difference in them under statistical analysis. It can be concluded that all of the tested agents were effective in regaining mineral loss. FV may be recommended as a professional topical fluoride. It is as effective, if not more so, as traditionally used APF gel. Also 0.4% SnF₂ home gel is an efficient self-applied topical fluoride for daily use.     

In vitro enamel erosion and abrasion-inhibiting effect of different fluoride varnishes

ObjectiveTo investigate the erosion and abrasion inhibiting effect of CPP-ACP/NaF and xylitol/NaF varnishes.MethodsBovine enamel samples (n = 40) were exposed to the following treatments (n = 10): NaF varnish (Duraphat^®, positive control); CPP-ACP/NaF varnish (MI varnishTM); xylitol/NaF (Profluorid^®) or distilled and deionized water (MilliQ^®, negative control). The samples were submitted for 3 days to 4 cycles/day of erosion (5 min in Sprite Zero) and 2 cycles of abrasion/day after the first and last erosive challenge, with a toothbrush machine and slurries of a placebo toothpaste for 15 s (50 strokes/s). Among the cycles and after the last daily cycle, the specimens remained in artificial saliva. The change in the enamel surface was evaluated by using 3D non-contact optical profilometry with surface roughness (Ra and Sa values) and tooth structure loss (TSL) measurements. Scanning electron microscopy (SEM) assessed the enamel topographic characteristics. Differences in the Ra, Sa and TSL among treatments were tested using one-way ANOVA followed by the Tukey test.ResultsAll varnishes promoted better results for Ra and Sa values than the negative control (p = 0.0001), without difference among them (p > 0.05). However, CPP-ACP/NaF varnish stimulated fewer TSL (7.09 ± 0.70 μm) compared to NaF varnish (10.33 ± 1.36 μm, p = 0.002), xylitol/NaF varnish (9.96 ± 0.41 μm, p = 0.007) and the negative control (18.38 ± 3.32 μm, p = 0.0001).ConclusionA single-application of fluoride topical varnishes was effective in reducing enamel wear. The CPP-ACP/NaF varnish had the best effect against enamel loss from an erosion-abrasion challenge.     

The effect of xylitol and fluoride on remineralization for primary tooth enamel caries in vitro

The effect of fluoride and xylitol on remineralization at the early stage of the enamel caries in primary tooth was studied. The samples were divided into four groups (control, 10% xylitol, 950 ppm NaF and 10% xylitol+950 ppm NaF) and analyzed by the using single thin section method and pHcycling model in vitro. The remineralizing ratio were control –8.9%, xylitol –0.4%, NaF 8.3% and xylitol + NaF 32.4%, respectively. Xylitol+NaF group particularly showed significantly smaller ΔZ value compared with 0 days (P<0.05). Therefore we assume that the effect of xylitol and fluoride are additive. We concluded that xylitol and fluoride treatment to the tooth enamel may be an effective caries-preventive measure in both primary and permanent tooth enamel.     

Efficacy of a mouthwash containing 0.8% arginine,PVM/MA copolymer,pyrophosphates, and 0.05% sodium fluoride compared to a commercial mouthwash containing 2.4% potassium nitrate and 0.022% sodium fluoride and a control mouthwash containing 0.05% sodium fluoride on dentine hypersensitivity: A six-week randomized clinical study

ObjectiveEvaluate the efficacy of 0.8% arginine, potassium nitrate and sodium fluoride mouthwashes on dentine hypersensitivity reduction.MethodsSix week randomized, double blinded, two cell, parallel single centre clinical study in the Dominican Republic; subjects were randomized into three treatment groups: mouthwash containing 0.8% arginine, PVM/MA copolymer, pyrophosphates, and 0.05% sodium fluoride in an alcohol-free base (arginine); mouthwash containing 2.4% potassium nitrate and 0.022% sodium fluoride (potassium nitrate); a control mouthwash containing 0.05% sodium fluoride (negative control). Tactile and air-blast dentine hypersensitivity assessments were conducted at baseline, thirty minutes post rinsing and two, four, and six weeks of twice-daily product use. For treatment group comparisons, ANCOVA and post hoc Tukey's pair-wise comparisons (α = 0.05) were done.ResultsSeventy-five subjects were enrolled; 69 subjects completed the study. There were no differences after thirty minutes of a single use, among the three groups with respect to mean tactile and air blast hypersensitivity scores compared to potassium nitrate and negative control mouthwashes (p < 0.05). The arginine group presented a statistically significant improvement in the mean tactile scores compared to potassium nitrate and negative control groups after two, four, and six weeks (p < 0.001) of product use; the arginine group showed a statistically significant enhancement in air blast hypersensitivity mean scores compared to potassium nitrate and negative control groups after two (p = 0.001), four (p < 0.001), and six weeks (p < 0.001) of product use.ConclusionA mouthwash containing arginine provides a significant and superior reduction in dentine hypersensitivity compared to potassium nitrate and a negative control mouthwash after two weeks.     

Strength of tunnel-restored teeth with different materials and marginal ridge height

ObjectiveThe aim of the study was to investigate the strength of the marginal ridge of tunnel preparations with different marginal ridge heights, using different restorative materials.Materials and methods120 sound premolars were randomly divided into three groups of standardized tunnel preparations with a remaining marginal ridge height of 1.5 mm, 2.5 mm and 3.5 mm, respectively. In each tunnel group, 10 teeth were filled with all four newly developed adhesive materials that had not previously been used in tunnel preparation: Ketac Aplicap, Fuji IX, Fuji II LC and Beautifil Flow F02. The control group comprised 10 sound teeth. All teeth were subjected to incremental dynamic force testing. Remaining marginal ridge height and restoration material were the independent variables. The mean maximum energy (MEI) score was the dependent variable. Data were analyzed, using one- and two-way analysis of variance. Scheffe's test and Student's t-test were used for comparison between groups.ResultsBoth restorative material (P < 0.0001) and remaining marginal ridge height (P < 0.0001) had a statistically significant effect on the mean MEI score of tunnel-prepared teeth. At the 2.5 mm of remaining marginal ridge height, no statistically significant difference in mean MEI score existed between Beautifil Flow F02-filled tunnel-prepared teeth and sound teeth.SignificancePremolars tunnel-restored with Beautifil Flow F02 at 2.5 mm distance from the marginal ridge were as strong as sound teeth.