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Introduction: In this study, we used metatranscriptomics for the first time to investigate microbial composition, functional signatures, and antimicrobial resistance gene expression in endodontic infections., Methods: Root canal samples were collected from ten teeth, including five primary and five persistent/secondary endodontic infections. RNA from endodontic samples was extracted, and RNA sequencing was performed on a NovaSeq6000 system (Illumina). Taxonomic analysis was performed using the Kraken2 bacterial database. Then, sequences with a taxonomic classification were annotated against the Universal Protein Knowledgebase for functional annotation and the Comprehensive Antibiotic Resistance Database for AR-like gene identification., Results: Proteobacteria, Bacteroidetes, Firmicutes, and Actinobacteria represented the dominant phyla, whereas Fusobacteria, Spirochetes, and Synergistetes were among the nondominant phyla. The top ten species were mainly represented by obligate (or quasiobligate) anaerobes, including Gram-negative (eg, Capnocytophaga sp. oral taxon 323, Fusobacterium nucleatum, Prevotella intermedia, Prevotella oris, Tannerella forsythia, and Tannerella sp. oral taxon HOT-286) and Gram-positive species (eg, Olsenella uli and Parvimonas micra). Transcripts encoding moonlighting proteins (eg, glycolytic proteins, translational elongation factors, chaperonin, and heat shock proteins) were highly expressed, potentially affecting bacterial adhesion, biofilm formation, host defense evasion, and inflammation induction. Endodontic bacteria expressed genes conferring resistance to antibiotic classes commonly used in dentistry, with a high prevalence and expression of tetracycline and lincosamide resistance genes. Antibiotic efflux and antibiotic target alteration/protection were the main resistance mechanisms., Conclusions: Metatranscriptomics revealed the activity of potential endodontic pathogens, which expressed putative virulence factors and a wide diversity of genes potentially involved in AR., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: A salt of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) was commercialized some years ago. This so-called Dual Rinse (DR) HEDP has been tested for its combined actions and interactions with pure sodium hypochlorite (NaOCl) solutions. The aim of this study was to assess DR interactions with NaOCl solutions containing proprietary additives., Methods: Designated endodontic NaOCl solutions that come at 2 different strengths (2% and 5.25%), and without or with additives (Chloraxid and Chloraxid Extra, respectively) were tested. Some of their key chemical and physical properties were determined in the presence or absence of HEDP (9%) in the solution. In addition, soft tissue dissolution efficacy of test and control solutions was assessed in extracted teeth (n = 10 per group, 90 teeth in total)., Results: The NaOCl content in the 2% Chloraxid solutions was slightly above, that in the 5.25% solutions below the labeled concentration. The additives in the Chloraxid Extra solutions neither altered their surface tension nor their viscosity. The addition of HEDP to any of the tested NaOCl solutions reduced their pH, and increased their surface tension and viscosity. HEDP-induced available chlorine loss over the first hour was similar between all NaOCl solutions. Soft tissue dissolution in the root canals was affected by NaOCl concentration, but neither by any proprietary NaOCl additive in the Chloraxid solutions, nor the addition of DR HEDP., Conclusions: Proprietary additives had no influence on any of the tested parameters, including surface tension of the "Extra" solutions. The increased viscosity of combined NaOCl/HEDP solutions deserves further attention., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this research was to investigate the effect of simplified adhesive strategies (self-etch vs selective enamel etch and 10- vs 20-second adhesive application time) on the marginal integrity in primary molars., Methods: Forty deep class-II cavities were prepared in 40 extracted primary molars. The molars were divided into 4 groups based on the applied universal adhesive strategy as follows: groups 1 and 2: selective enamel etch with 20- or 10-second application time and groups 3 and 4: self-etch with 20- or 10-second application time. All cavities were restored with a sculptable bulk-fill composite restoration. The restorations underwent a thermomechanical loading (TML, 5-50 °C, 2-minute dwelling time, ×1000; 400,000 loading cycles, 1.7 Hz, 49 N). Marginal analysis before and after TML was conducted with scanning electron microscopy and the marginal integrity of each restoration was calculated as a percentage of continuous margins. A beta regression model was adopted to statistically analyse the data with a consequent pairwise comparison., Results: The mean marginal integrity (% ± SD) of the restorations for each tested adhesive strategy after TML was as follows: selective enamel etch/20 seconds = 85.4 ± 3.9, self-etch/20 seconds = 85.3 ± 5.2, self-etch/10 seconds = 80.1 ± 8.2, and selective enamel etch/10 seconds = 80.0 ± 8.5. The difference between both adhesive strategies was not statistically significant at the same application time. The difference between both application times within the same adhesive strategy was statistically significant (P ≤ .01)., Conclusions: Universal adhesives applied either in selective enamel etch or in self-etch mode result in comparable marginal integrities when restoring class-II cavities in primary molars. Shortened adhesive application time (10 seconds) could lead to a reduction in the marginal integrity in comparison to the recommended application time of 20 seconds., Competing Interests: Conflict of interest Non disclosed., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: To prepare experimental composites with bioactive glass (BG) and investigate their release of calcium (Ca), phosphate (PO 4 ), and fluoride (F), as well as pH changes and apatite precipitation after immersion., Methods: Experimental composites were prepared with 0, 10, or 20 wt% of either BG 45S5 or a customized low-Na F-containing BG. Three commercial ion-releasing materials were used for reference. Material specimens were immersed in lactic acid (pH = 4.0) and artificial saliva (pH = 6.4). Ion concentrations (atomic absorption spectrometry for Ca, UV-vis spectrometry for PO 4 , and ion-selective electrode for F) and pH were measured after 4, 8, 12, 16, 20, 24, 28, and 32 days. After immersion, composite specimens were analyzed using scanning electron microscopy (SEM) and Fourier-transform infrared (FTIR) spectroscopy., Results: Material-dependent concentrations of Ca, PO 4 , and F were measured in the lactic acid solution, while a decrease of Ca and PO 4 concentrations was observed in artificial saliva. The uptake of ions from artificial saliva indicates their precipitation on specimen surfaces, which was supported by the results of SEM and FTIR investigations. In experimental composites functionalized with both bioactive glass types and a commercial "alkasite" material, apatite was precipitated not only in artificial saliva but also in the lactic acid solution., Conclusions: Experimental BG-containing composites and selected commercial restorative materials demonstrated the potential for releasing multiple ion types and increasing pH., Clinical Significance: The observed effects can be beneficial for preventing demineralization and promoting remineralization of dental hard tissues, while apatite precipitation can additionally help in sealing marginal discontinuities., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Objectives: This study aimed to investigate the additional clinical benefit of tricalcium phosphate (TCP) (-containing) biomaterials compared to open flap debridement (OFD) in periodontal infra-bony defects., Data: A literature search was conducted in Pubmed, Embase and Cochrane library for entries published up to 14th July 2021. All randomized controlled trials (RCTs) that compared a TCP (-containing) material with OFD and studies that assessed a beta-TCP group alone, with vertical defect sites with PPD of ≥ 6 mm and/or presence of infra-bony defects of ≥ 3 mm and a minimum follow-up of 6 months were included. Risk of bias was assessed with the Oxford scale. The random-effects (RE) model was synthesized as differences between weighted average (MD) for probing pocket depth (PPD) and clinical attachment level (CAL) between TCP and OFD groups. An RE analysis was also performed for the beta-TCP group alone., Study Selection: Data from 16 RCTs were included in the analysis. Six studies that represented 151 patients and sites were selected for meta-analysis. The overall MD with 95% CI at 6 months was calculated to be -0.47 [-0.83, -0.12; P = 0.0087] and -1.06 [-1.67, -0.46; P = 0.0006] for PPD and CAL, respectively. Whereas MD at 12 months for PPD and CAL was -0.89 [-1.54, -0.23; P = 0.0078] and -1.25 [-1.85, -0.66; P<0.0001], respectively. All results were in favor of TCP (-containing) group over OFD., Conclusions: The results of the study suggest that the use of a TCP (-containing) material may have the potential for additional clinical improvement in PPD and CAL compared with OFD in infra-bony defects, given the limitations of the included evidence., Clinical Significance: The use of TCP as a bone graft substitute is becoming increasingly common. Therefore, it would be advantageous if an adjunctive benefit in the regeneration of infra-bony defects could be demonstrated to facilitate material selection., (Copyright © 2021 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objectives: To investigate the effect of rapid high-intensity light-curing on the marginal integrity of four bulk-fill composites, including two materials specifically designed for high-intensity curing., Methods: Class V cavities were prepared on buccal surfaces of intact human molars with simulated pulpal pressure, filled in a single increment and light-cured using a conventional (10 s @ 1,340 mW/cm 2 ) or high-intensity (3 s @ 3,440 mW/cm 2 ) protocol. The restorations were subjected to thermo-mechanical loading (TML) comprising 1,200,000 mechanical loading cycles and 3,000 thermocycles. Quantitative margin analysis was performed before and after TML using a scanning electron microscope, and the marginal integrity was expressed as percentage of continuous margin (PCM)., Results: All PCM values measured before TML were statistically similar regardless of the material and curing protocol (p>0.05). A statistically significant effect of the curing protocol (p = 0.021) was identified only after TML for one material. PCM was significantly diminished by TML (p<0.001) for most combinations of material and curing protocol. The PCM values of the sculptable composites after TML were statistically similar regardless of the curing protocol (p>0.05). Compared to these values, significantly lower PCM after TML was identified for the flowable composites cured with the high-intensity protocol (p = 0.001-0.045)., Conclusion: In most cases, high-intensity and conventional curing generally led to similar marginal integrity. Although all of the investigated composites initially performed similarly well, the flowable composites light-cured using the high-intensity protocol showed a significantly inferior marginal integrity compared to the sculptable composites after loading., Clinical Significance: Rapid high-intensity light-curing cannot be recommended for flowable bulk-fill composites since it may compromise the tooth-restoration interface., (Copyright © 2021. Published by Elsevier Ltd.)

This in vitro study used the same frequency and duration of acid contact as a previous in situ/in vivo study to evaluate the effect of erosion on CAD/CAM restorative materials and human enamel and to compare the effects of in vitro and in situ/in vivo acid challenges on CAD/CAM restorative materials and human enamel. The CAD/CAM restorative materials (IPS e.max CAD, Lava Ultimate, and PMMA block) and human enamel were eroded by immersion in 150 ml of cola drink for 14 days (4 × 5 min/day). The surface microhardness and surface roughness of the specimens were measured at baseline (T1), day 7 (T2), and day 14 (T3). The substance losses were measured at T2 and T3. The data were statistically analyzed using repeated measures ANOVA and Bonferroni's test (α = 0.05). Erosion significantly decreased the surface microhardness of the CAD/CAM restorative materials and human enamel (all P < 0.001). The overall percentage of surface microhardness loss (%SMH l ) of the PMMA block and enamel due to in vitro erosion was significantly higher than that due to in situ/in vivo erosion (P = 0.02 and P < 0.001, respectively). Consistent with in situ/in vivo erosion, the surface roughness and profile of the tested restorative materials remained unchanged after in vitro erosion. A significant increase in the surface roughness and substance loss was observed for enamel after in vitro erosion (all P < 0.001). The overall substance loss of enamel due to in vitro erosion was significantly higher than that due to in situ/in vivo erosion (P < 0.001). In conclusion, erosion decreased the surface microhardness of the CAD/CAM restorative materials and human enamel. Moreover, erosion negatively influenced the substance loss and surface roughness of human enamel. For the substance loss of enamel and %SMH l of PMMA block and enamel, the in vitro erosive effects were approximately 1-2 times greater than the in situ/in vivo effects. However, for the surface roughness and profile of the CAD/CAM restorative materials, no significant difference was found between in vitro and in situ/in vivo erosion., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background & Aims: Oral nutritional supplements (ONS) administered to malnourished elders and other patients contain high-levels of carbohydrates that could be a potential risk factor for dental caries. This study aimed to evaluate the cariogenic potentials of ONS using intraoral plaque telemetry., Methods: Ten ONS were tested on five healthy volunteers (mean age: 76.8 ± 9.15 years). Participants were requested to refrain from performing oral hygiene 3-7 days prior to testing. The pH-value below the dental plaque on the tooth was measured while the ONS was being consumed. After neutralizing the participant's saliva, a control solution (10% sucrose) was administered and telemetry measurements were repeated. Mean relative cariogenicity (RC) was calculated for each ONS. ANOVA and post hoc tests were used for statistical analyses (p < 0.05)., Results: All ten ONS were potentially cariogenic on enamel with an overall RC of 0.519 ± 0.35 (Range: Min = 0.31 ± 0.16; Max = 1.00 ± 0.34). RC differed significantly between the ONS (p = 0.002). RC was lower in ONS that contained high-protein (p = 0.018). RC was not influenced by other factors such as readily consumable (p = 0.102), flavor (p = 0.869), consistency (p = 0.126), fiber containing (p = 0.134), style (p = 0.112), and age of plaque (p = 0.339)., Conclusions: The ONS administered to elders and malnourished patients are potentially cariogenic. It is imperative that the administration of ONS must be based on individual needs to potentiate a maximum benefit. Wherever possible, an attempt to limit the use of high-carbohydrate containing ONS must be practiced along with the adoption of suitable preventive measures to arrest the development and progression of caries., Competing Interests: Conflict of interest AS, IN, TA, MS: declare no conflicts of interest. FW: member of the board of Toothfriendly Switzerland., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Hydrogen peroxide (H 2 O 2 ) and sodium hypochlorite (NaOCl) solutions are similar in that they contain oxidizing agents with a bleaching effect. NaOCl solutions are stable at a high pH, at which they also exert increased cleansing/proteolysis. On the other hand, H 2 O 2 solutions are natively acidic, yet gain bleaching power on organic stains when alkalized. It was investigated whether alkalizing a H 2 O 2 solution would also let it dissolve soft tissue or increase its bleaching power on blood-stained dentin., Methods: The stability of alkalized H 2 O 2 solutions was assessed by iodometric titration. Soft tissue dissolution was investigated on porcine palatal mucosa. The bleaching effect (ΔL∗) after 60 minutes of exposure was monitored in blood-stained human dentin using a calibrated spectrophotometer. To compare similar molarities, 2.5% H 2 O 2 solutions were used here, and 5.0% NaOCl was used as the positive control, whereas nonbuffered saline solution served as the negative control., Results: Adding alkali (NaOH) to the H 2 O 2 solutions rendered them unstable in a dose-dependent manner. A H 2 O 2 solution of pH 11.1 was chosen for the main experiments (tissue dissolution and bleaching effect) and compared with a native counterpart (pH = 4.7). Alkalizing the H 2 O 2 solution had no discernible effect on its soft tissue dissolution or bleaching power (P = .75 compared with the native H 2 O 2 solution). The NaOCl solution of similar molar concentration had a considerably (P < .001) higher tissue dissolving and bleaching effect under current conditions., Conclusions: The proteolytic/bleaching effects of NaOCl solutions are unique and cannot be achieved by altering the pH of peroxide solutions., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

This study aimed to evaluate the effects of repolishing on the surface microhardness (SMH), color change (ΔE), and translucency parameter (TP) of previously in situ eroded computer-aided design/computer-aided manufacturing (CAD/CAM) restorative materials and human enamel. Each of 8 volunteers wore an intraoral appliance containing 3 CAD/CAM restorative material specimens (IPS e.max CAD lithium disilicate ceramic, Lava Ultimate hybrid ceramic, and poly (methyl methacrylate) (PMMA) block) and 1 human enamel specimen. The specimens were subjected to in situ erosion cycles by rinsing with a cola drink (4 × 5 min/day) for 14 days. After erosion, the specimens were polished with a silicone polishing system (Ceramister, Shofu Inc, Kyoto, Japan). The SMH and color of the specimens were determined at baseline (T1), after erosion (T2), and after repolishing (T3). The ΔE and TP values of the specimens were further calculated. The data were statistically analyzed using repeated-measures analysis of variance (ANOVA) and Bonferroni's test (α = 0.05). After erosion, a decrease in the SMH of the restorative materials and enamel was observed (all P < 0.001), and a decrease in the TP of the enamel was observed (P = 0.016). The ΔE values of the enamel (ΔE = 7.32) and Lava Ultimate (ΔE = 3.19) exceeded the clinically unacceptable threshold after erosion. After repolishing, the SMH of the restorative materials and enamel at T3 was significantly higher than that at T2 (all P < 0.001). No significant difference was found in the TP and ΔE values of the restorative materials and enamel between T2 and T3. In conclusion, erosion negatively affected the surface properties and appearance of the CAD/CAM restorative materials and human enamel. Repolishing contributed to restoring the compromised SMH of the eroded restorative materials and enamel to a certain extent. However, repolishing did not restore the color of the eroded restorative materials and enamel., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objectives: To compare the effect of high-intensity (3 s with 3440 mW/cm 2 ) and conventional (10 s with 1340 mW/cm 2 ) light-curing on shrinkage properties and degree of conversion of conventional and bulk-fill resin composites, including two composites specifically designed for high-intensity curing., Methods: Real-time linear shrinkage and shrinkage force of 1.5 mm thick composite specimens were measured for 15 min after the start of light-curing using custom-made devices. From the shrinkage force data, maximum shrinkage force rate and time to achieve maximum shrinkage force rate were determined. Degree of conversion was measured using Fourier transform infrared spectrometry., Results: Flowable composites showed significantly higher linear shrinkage compared to sculptable composites (1.93-2.91 % vs. 1.15-1.54 %), as well as significantly higher shrinkage forces (18.7-24.4 N vs. 13.5-17.0 N). Degree of conversion amounted to 45.8-60.1 %. For high-intensity curing, degree of conversion was significantly lower in three out of seven composites, whereas shrinkage forces were either increased, decreased, or unchanged compared to conventional curing. For high-intensity curing, maximum shrinkage rates were 6-61 % higher, whereas times to achieve maximum shrinkage force rate were 15-53 % shorter compared to conventional curing. Composites specifically designed for high-intensity curing showed shrinkage parameters comparable to other investigated composites., Conclusion: Shrinkage behavior under conditions of high-intensity light-curing was material-dependent. Shrinkage force kinetics were more strongly affected by high-intensity curing than absolute values of linear shrinkage and shrinkage force., Clinical Significance: Despite being attractive for its convenience, high-intensity curing can lead to considerably faster development of shrinkage forces in the early stage of polymerization., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

This in situ/in vivo study aimed to evaluate the effects of erosion on the surface microhardness, substance loss, and surface roughness of CAD/CAM restorative materials and human enamel. This study used a 2-treatment (14 days each) crossover design with 8 healthy volunteers. Each volunteer wore an intraoral appliance containing 3 CAD/CAM restorative material specimens [IPS e.max CAD, Lava Ultimate CAD/CAM Restorative, and a poly (methyl methacrylate) (PMMA) block for CAD/CAM] and 1 human enamel specimen. The specimens were subjected to in vivo erosion cycles by rinsing with 150 ml of cola drink (4 × 5 min/day) for 14 days. The surface microhardness, substance loss, and surface roughness of the specimens were measured at baseline (T1), day 7 (T2) and day 14 (T3). The data were statistically analyzed using repeated measures ANOVA and Tukey's test (α = 0.05). After erosion, significant increases in substance loss and surface roughness were observed for enamel, though the surface roughness and substance profile of the tested restorative materials remained unchanged. Erosion significantly decreased the surface microhardness of all materials. For IPS e.max and Lava Ultimate, a significantly higher percentage of surface microhardness loss (%SMH l ) was found at T3 than at T2, while no significant difference was found between T2 and T3 for enamel and the PMMA block. In conclusion, CAD/CAM restorative materials showed smaller changes in surface roughness and the surface profile than human enamel after in situ/in vivo erosion. However, CAD/CAM restorative materials and human enamel showed similar changes in surface microhardness after in situ/in vivo erosion., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objectives: To evaluate the short-term effects of stain-causing beverages on the effectiveness of in-office tooth bleaching., Methods: Participants were recruited and randomly divided into 3 groups based on beverages used for rinsing during and after the bleaching procedure: group N (tap water, control group), group C (coffee), and group T (tea). Participants were instructed to rinse with the respective solutions for 30 s, 4 times daily for 4 weeks. All participants received two in-office bleaching treatment sessions with 40 % hydrogen peroxide (Opalescence BOOST PF 40 %, Ultradent); the sessions were separated by a 1-week interval. Tooth colour was assessed using a spectrophotometer (Easyshade, Vita ZahnFabrik) before the bleaching procedure (T0), immediately after the first session of bleaching (T1), immediately after the second session of bleaching (T2), as well as one week (T3) and three weeks after (T4) the end of bleaching. Tooth sensitivity (TS) was ranked using a numerical rating scale (NRS) and a visual analogue scale (VAS) at different time points., Results: No significant difference in the whiteness index (W), △E, △a* and △b* values among the 3 groups was observed at any time interval (P for all > 0.05). At T4, the △L* value in group C was significantly lower than that in groups T and N (P = 0.022 and P = 0.001, respectively), though no significant difference in △L* values was observed among the 3 groups at T1 (P = 0.402), T2 (P = 0.643) and T3 (P = 0.177). Additionally, no significant difference was found in the TS values among the 3 groups at any of the evaluation time points (P for all > 0.05)., Conclusions: Exposure to coffee or tea during the bleaching treatment period did not affect the effectiveness of the treatment. However, exposure to coffee after the bleaching treatment did affect the effectiveness of the treatment. Exposure to stain-causing beverages did not affect the bleaching-induced TS (ClinicalTrials.gov Identifier: NCT03933527)., Clinical Significance: The consumption of coffee or tea during tooth bleaching may not interfere with the colour change produced by the treatment. However, clinicians should advise their patients to refrain from, at least to some extent, consuming coffee after the bleaching procedure to maintain the effectiveness of the treatment., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Objectives: The study evaluated the suitability of pure crystalline hydroxyapatite (HA) as a substitute for human (H) and bovine (B) enamel in erosion experiments., Methods: Human and bovine enamel and hydroxyapatite specimens (n = 18 each) were submitted to demineralisation by HCl at pH values of 3.0, 2.6 and 2.0 (1.0, 2.5, and 10 mmol/l concentration). Specimens were eroded in a superfusion chamber for 7 min (flow rate: 1 μl/s). Multiple fluid samples were taken per specimen throughout the exposure period. The dissolved calcium content was measured using a colorimetric assay with Arsenazo III reagent, to serve as surrogate for erosive substance loss. Additionally, erosive tissue loss was quantified by profilometry. Differences in erosive substance loss were assessed by the Kruskal-Wallis and Conover's posthoc test., Results: Good agreement in erosive substance loss between HA and human specimens was found at pH 2.6, as no statistically significant difference and considerable overlap of their respective interquartile ranges was observed. At pH 2.0 and 3.0, a statistically significant difference between HA and human and bovine enamel was determined. HA consistently tended to have lower mean dissolution rates, with a maximum deviation from human enamel of -16% at pH 3. It displayed lower specimen variability with an average coefficient of variation of 17%, compared to 25% (H) and 25% (B), respectively., Conclusions: Crystalline hydroxyapatite may not be suitable for full substitution of biologic enamel in erosion experiments focusing on absolute measurement values, but is useful for establishing consistent relative trends between erosive agents due to biosimilar erosion behavior and lower experimental variability. This is especially true for preliminary studies where approval for use of biological samples is restricted., Clinical Significance: Crystalline hydroxyapatite is a useful substitute of human or bovine enamel in experiments studying chemical aspects of dental erosion., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objectives: To assess the efficacy of 8% arginine containing prophylaxis products over 24 weeks in subjects with dentin hypersensitivity (DH)., Methods: 297 patients with established DH (Schiff score 2, 3) in three European study centers were randomly assigned to either 8% arginine and calcium carbonate in-office prophylaxis paste and the respective toothpaste (test group) or fluoride-free prophylaxis paste and sodium monoflourophosphate toothpaste as a negative control group. Air blast (Schiff Score) and tactile (Visual Analog Scale) sensitivity scores were assessed at baseline (BL&#95;0), after single application of the prophylaxis paste (BL&#95;1) and after 4, 8, and 24 weeks of continuous at-home use of the toothpaste., Results: 273 subjects completed the study. Test and control group presented statistically significant percentage reductions (t-test, p < 0.05) in Schiff Score at BL&#95;1 and at 24 weeks relative to BL&#95;0 (difference in %; test group: -23.6, -44.9, control group: -8.8, -32.7). The pooled Schiff Score for the two evaluated teeth yielded a significantly greater alleviation of DH in the test group than in the control group at all evaluation appointments (Ancova, p < 0.05; difference in %: 15.3, 7.4, 10.6, 17.2)., Conclusions: A significant relief of DH was demonstrated after application of the 8% arginine prophylaxis products over 24 weeks compared to a negative control., Clinical Significance: Whilst DH is influencing patients' eating, drinking and tooth brushing habits as well as social life interactions it is important that clinicians are able to offer evidence based immediate and long-lasting treatment methods in order to manage their patients' discomfort., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Objective: This in situ study aimed to evaluate the protective effect of Tooth Mousse (GC) containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on human enamel erosion and to compare the difference in erosion between the anteriorly and posteriorly positioned human enamel., Methods: This study used a 2-treatment (7 days each) crossover design with 12 healthy volunteers wearing intraoral appliances. Each appliance contained 4 human enamel specimens positioned on the buccal surfaces of the volunteers' maxillary central incisors and first molars. The specimens were intraorally treated withTooth Mousse (CPP-ACP group) or deionized water (control group) for 3 min and then exposed to in vivo acid attacks by rinsing with 150 ml of a cola drink (4 × 5 min/day). The surface microhardness (SMH) of the specimens was measured and used to calculate the percentage of SMH loss (%SMH l ). Erosion effect on enamel was also investigated by scanning electron microscopy (n = 4) at the end of study. The data were statistically analysed using two-way analysis of variance (ANOVA) and Tukey's test at a level of P < 0.05., Results: A significant decrease in %SMH l was observed for the specimens of CPP-ACP group compared to that for the controls (P = 0.007). The specimens positioned posteriorly exhibited a significantly lower %SMH l than those positioned anteriorly (P = 0.033). Samples of CPP-ACP group showed fewer etching patterns than those of the control group., Conclusions: In this in situ model, application of Tooth Mousse containing CPP-ACP before erosion reduced the %SMH l of human enamel. Enamel located in different positions showed different patterns of erosion., Clinical Significance: Application of Tooth Mousse containing CPP-ACP could be considered as a suitable preventive strategy against enamel erosion. ClinicalTrials.gov Identifier: NCT03426150., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Objectives: Aim of this investigation was to study the temperature-dependent in vitro enamel erosion of five acidic drinks and citric acid under controlled conditions in an artificial mouth., Methods: The erosive potential of Orange juice, Coca-Cola Zero, Sprite Zero, two fruit teas and citric acid (control) was investigated on bovine enamel specimens at temperatures between 5 °C and 55 °C. The pH values and total calcium content of all test drinks were determined. Specimens were immersed into an artificial mouth to imitate physiological oral conditions for 60 h. Cyclic de- and re-mineralization was performed, imitating the intake of six drinks in six h followed by a six-hour remineralization phase, where only artificial saliva ran over the specimens. Total erosive enamel loss was determined by contact profilometry. Differences in substance loss at different temperatures were tested for statistical significance (p-values ≤ 0.05) by means of ANOVA., Results: Rising liquid temperature did not result in a considerable change of pH. Highest substance loss was observed for citric acid (33.6 ± 6 μm to 38.7 ± 6 μm), while only little erosion was induced by fruit tea (0.8 ± 1 μm to 5.9 ± 1 μm). Rising liquid temperature did not result in significantly increased substance loss for citric acid, orange juice and Coca-Cola Zero. Sprite Zero and both fruit teas, however, caused significantly (p < 0.001) more enamel loss at elevated temperature., Conclusions: Not all investigated drinks showed a temperature-induced change in erosivity., Clinical Significance: For some erosive beverages it can be recommended to keep the consummation temperature as low as possible to decrease the risk of erosive tooth substance loss., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Introduction: A clinically useful all-in-one endodontic irrigant with combined proteolytic and decalcifying properties is still elusive. In this study, the chemical effects of dissolving the tetrasodium salts of 1-hydroxyethane 1,1-diphosphonic acid (Na 4 HEDP) or Na 4 EDTA directly in sodium hypochlorite (NaOCl) irrigants in polypropylene syringes were assessed during the course of 1 hour., Methods: The solubility of the salts in water was determined. Their compatibility with 1% and 5% NaOCl was measured by iodometric titration and in a calcium complexation experiment by using a Ca 2+ -selective electrode., Results: The salts dissolved within 1 minute. The dissolution maximum of Na 4 HEDP in water (wt/total wt) was 44.6% ± 1.6%. The corresponding dissolution maximum of Na 4 EDTA was 38.2% ± 0.8%. Na 4 HEDP at 18% in 5% NaOCl caused a mere loss of 16% of the initially available chlorine during 1 hour. In contrast, a corresponding mixture between NaOCl and the Na 4 EDTA salt caused 95% reduction in available chlorine after 1 minute. Mixtures of 3% Na 4 EDTA with 1% NaOCl were more stable, but only for 30 minutes. Na 4 HEDP lost 24% of its calcium complexation capacity after 60 minutes. The corresponding loss for Na 4 EDTA was 34%., Conclusions: The compatibility and solubility of particulate Na 4 HEDP with/in NaOCl solutions are such that these components can be mixed and used for up to 1 hour. In contrast, short-term compatibility of the Na 4 EDTA salt with NaOCl solutions was considerably lower, decreasing at higher concentrations of either compound. Especially for Na 4 HEDP but also for Na 4 EDTA, the NaOCl had little effect on calcium complexation., (Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: The aims of this study were (1) to investigate prevalence, severity and distribution of erosive tooth wear in German kindergarten children aged 3-6 years in 2014/15 in comparison to an earlier survey from 2004/05 and (2) to identify and compare possible risk factors., Methods: 775 children aged 3-6 years from 27 kindergartens were examined in 2014/15 and compared to the data from 2004/05 (432 children/21 kindergartens). Erosive tooth wear was examined using the O'Sullivan-Index. Additionally, data were converted into the Basic Erosive Wear Examination (BEWE)-index. Information about dietary habits, chronic illness and oral hygiene practices were obtained by questionnaires. Statistical analyses were done by Chi(2)-, Mann-Whitney U Tests and regression analyses (p<0.05)., Results: Compared to 2004/05 (31.3%) prevalence of erosive tooth wear was significantly increased in 2014/15 (45.4%). In 2004/05 and 2014/15, prevalence increased significantly with increasing age of the children: 3-year-olds: 22.5%/14.2%; 4-year-olds: 27.4%/32.9%; 5-year-olds: 30.5%/58.8%; 6-year-olds: 38.1%/71.7%. Children with erosive tooth wear presented more affected teeth and a higher severity of erosive tooth wear, respectively, in 2014/15 compared to 2004/05. The BEWE score sum was significantly higher in 2014/15 (3-year-olds: 3.4±2.1, 4-year-olds: 4.2±3.1, 5-year-olds: 4.6±2.9, 6-year-olds: 5.9±3.3) than in 2004/05 (3-year-olds: 2.0±1.2, 4-year-olds: 2.7±1.8, 5-year-olds: 2.7±2.4, 6-year-olds: 4.2±4.2). In 2014/15, age and male gender were significant with respect to the presence of erosive tooth wear. Severity of erosive tooth wear was dependent on the regular consumption of fruit juices and lemonade/coke., Conclusion: The prevalence of erosive tooth wear in German kindergarten children has increased in the last ten years., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objectives: This study aimed to analyze interactions between oral biofilms and a dental triethylene glycol dimethacrylate (TEGDMA)-based resin infiltration material on enamel., Methods: Demineralized enamel specimens (14 days, acidic buffer, pH 5.0) were either infiltrated with a commercial TEGDMA resin and subjected to a three-species biofilm (Streptococcus mutans UAB 159, Streptococcus oralis OMZ 607 and Actinomyces oris OMZ 745) (group 1), applied to the biofilm (group 2), or merely resin infiltrated (group 3). A control group received no treatment (4). Biofilm formation and metabolic activity of biofilms were measured for group (1) and (2) after 24h CFU and a resazurin assay. Resin biodegradation was measured for group (1) and (3) by high performance liquid chromatography (HPLC) coupled with mass spectrometry after 6 and 24h incubation. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) images were taken to study the biofilm and material's autofluorescence in groups (1-4) after 24h., Results: SEM and CLSM images showed reduced biofilm formation on resin-infiltrated specimens (group 1) compared to group 2, while no biofilm was detectable on groups 3 and 4. CFU data (log10 CFU per mL) of group 1 showed significantly reduced bacterial numbers (p<0.05) compared to group 2. However, HPLC analysis of TEGDMA leakage after 6h and 24h revealed no differences between group 1 and group 3., Conclusions: The results of the current study indicate that freshly resin-infiltrated enamel surfaces show a biofilm reducing effect, while monomer leakage was not affected by bacterial presence., Clinical Significance: Resin infiltrated enamel surfaces are constantly exposed to the oral microflora. Yet, it is not known how biofilms interact with enamel-penetrated resins and if and to which extent accessory alignments in oral hygiene are needed., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Objectives: To investigate the influence of pre-heating of high-viscosity bulk-fill composite materials on their degree of conversion and shrinkage force formation., Methods: Four bulk-fill composite materials (Tetric EvoCeram Bulk Fill-TECBF, x-tra fil-XF, QuixFil-QF, SonicFill-SF) and one conventional nano-hybrid resin composite (Tetric EvoCeram-TEC) were used. The test materials were either kept at room temperature or pre-heated to 68°C by means of a commercial heating device, before being photoactivated with a LED curing unit for 20s at 1170mW/cm(2). Shrinkage forces (n=5) of 1.5-mm-thick specimens were recorded in real-time for 15min inside a temperature-controlled chamber at 25°C (simulating intraoral temperature after rubber dam application) with a custom-made stress analyzer. Degree of conversion (n=5) was determined at the bottom of equally thick (1.5mm) specimens using Fourier transform infrared spectroscopy. Data were analyzed with Student's t-test, ANOVA and Tukey's HSD post-hoc test (α=0.05)., Results: Composite pre-heating significantly increased the degree of conversion of TECBF, but had no effect on monomer conversion of the other materials investigated. For each of the test materials, pre-heated composite generated significantly lower shrinkage forces than room-temperature composite. At both temperature levels, TECBF created the significantly highest shrinkage forces, and QF caused significantly higher shrinkage forces than both XF and TEC., Conclusions: Both the composite material and the pre-cure temperature affect shrinkage force formation. Pre-heating of bulk-fill and conventional restorative composites prior to photoactivation decreases polymerization-induced shrinkage forces without compromising the degree of conversion., Clinical Significance: Composite pre-heating significantly reduces shrinkage force formation of high-viscosity bulk-fill and conventional resin composites, while maintaining or increasing the degree of monomer conversion, dependent upon the specific composite material used., (Copyright © 2015. Published by Elsevier Ltd.)

Objectives: This randomised in situ study aimed to analyse the effect of milk (with or without 5ppm F) and CPP-ACP pastes (with or without 900ppm F) on dental erosion., Methods: The study was a seven phase (5 days each) crossover design involving 15 participants wearing intraoral appliances with enamel and dentine specimens. Specimens were extraorally eroded (erosive soft drink, 6×90s/day) and brushed (2×30s/day, 2N) using a non-fluoridated toothpaste (negative control). The test products were milk, milk+5ppm F (twice daily, each 100ml/2min), CPP-ACP paste, CPP-ACP paste+900ppm F (3min/day) or a SnCl2/AmF/NaF mouthrinse (positive control, 30s/day), which were applied immediately after erosion with the appliances in the oral cavity. In an additional group, a fluoridated toothpaste was used without any additional test product. Tissue loss was determined profilometrically after 5 days and statistically analysed by linear mixed models methodologies (p<0.05)., Results: Compared with the negative control (non-fluoridated toothpaste only, enamel: 2.2±1.3μm; dentine: 3.8±2.2μm), enamel and dentine loss was significantly reduced by the use of fluoridated toothpaste (enamel: 1.1±1.0μm; dentine: 2.4±1.7μm) and the SnCl2/AmF/NaF mouthrinse (1.5±1.5μm; dentine: 1.8±1.9μm)., Conclusions: Milk and CPP-ACP were not effective in reducing enamel and dentine loss significantly, independently of the presence of fluoride., Clinical Significance: Enamel and dentine erosion were significantly reduced by the use of a fluoridated toothpaste or a SnCl2/AmF/NaF mouthrinse, but not by milk or CPP-ACP under the conditions of the present study., Clinical Trials Registration: NCT01566357., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objectives: To test the hypothesis that a material with higher water absorption than polyvinylidene fluoride (PVDF) could increase the yield of target molecules from exposed dentine., Methods: In a series of standard tests, different cellulose membranes were compared to a PVDF counterpart for their ability to absorb water and release protein. In a subsequent randomized clinical trial, the cellulose material with the most favourable values was compared to PVDF regarding the levels of MMP-2 that could be collected from exposed dentine of healthy human teeth during filling replacement. MMP-2 levels were determined by enzyme-linked immunosorbent assay (ELISA). Data from the laboratory experiments were compared between materials using the appropriate parametric tests. The frequency of cases yielding quantifiable levels of MMP-2 was compared between materials by Fisher's exact test. The level of significance was set at 5%., Results: The cellulose membrane with the largest pore size (12-15μm) absorbed significantly (P<0.05) more water than PVDF. It showed a protein release that was similar to that of PVDF, while the cellulose membranes with smaller pore size retained significantly more protein (P<0.05). Using the large-pore cellulose membrane, MMP-2 could be collected at a quantifiable level from the dentine of healthy teeth in 9 of 13 cases, compared to 1 of 13 with the PVDF membrane (P<0.05)., Conclusions: Under the current conditions, a large-pore cellulose membrane yielded more of a molecule of diagnostic value compared to a standard PVDF membrane., Clinical Significance: Molecular diagnostics of dentinal fluid are hampered by low yields. In the current study, it was shown that cellulose membranes are more useful to collect MMP-2 from dentinal fluid than PVDF membranes., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: This in vitro study aimed to investigate the preventive effect of brushing with anti-erosive toothpastes compared to a conventional fluoride toothpaste on dentine erosion., Materials and Methods: Bovine dentine specimens (n=12 per subgroup) were eroded in an artificial mouth (6 days, 6×30 s/day) using either citric acid (pH:2.5) or a hydrochloric acid/pepsin solution (pH:1.6), simulating extrinsic or intrinsic erosive conditions, respectively. In between, the specimens were rinsed with artificial saliva. Twice daily, the specimens were brushed for 15 s in an automatic brushing machine at 2.5 N with a conventional fluoride toothpaste slurry (elmex, AmF) or toothpaste slurries with anti-erosive formulations: Apacare (NaF/1% nHAP), Biorepair (ZnCO3-HAP), Chitodent (Chitosan), elmex Erosionsschutz (NaF/AmF/SnCl2/Chitosan), mirasensitive hap (NaF/30% HAP), Sensodyne Proschmelz (NaF/KNO3). Unbrushed specimens served as control. Dentine loss was measured profilometrically and statistically analysed using two-way and one-way ANOVA followed by Scheffe's post hoc tests. RDA-values of all toothpastes were determined, and linear mixed models were applied to analyse the influence of toothpaste abrasivity on dentine wear (p<0.05)., Results: Dentine erosion of unbrushed specimens amounted to 5.1±1.0 μm (extrinsic conditions) and 12.9±1.4 μm (intrinsic conditions). All toothpastes significantly reduced dentine erosion by 24-67% (extrinsic conditions) and 21-40% (intrinsic conditions). Biorepair was least effective, while all other toothpastes were not significantly different from each other. Linear mixed models did not show a significant effect of the RDA-value of the respective toothpaste on dentine loss., Conclusion: Toothpastes with anti-erosive formulations reduced dentine erosion, especially under simulated extrinsic erosive conditions, but were not superior to a conventional fluoride toothpaste., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objectives: To investigate the effect of saliva substitutes on enamel erosion in vitro., Methods: A total of 204 bovine enamel samples were embedded in acrylic resin and allocated to 17 groups (n=12). The specimens were eroded in an artificial mouth (3 days; 6×30 s/days, flow rate: 2 ml/min) using citric acid (pH: 2.5). Immediately after the erosive attacks, saliva substitutes (12 sprays, 3 gels) were applied. Between the erosive cycles the specimens were rinsed with artificial saliva (flowrate: 0.5 ml/min). A SnCl2/AmF/NaF-containing mouthrinse was used as positive control, water spray served as negative control. Enamel loss was measured profilometrically and the data were analyzed using one-way ANOVA followed by Scheffé's post hoc tests (p<0.05)., Results: Four saliva substitutes increased enamel erosion, probably due to the low pH or the content of citric acid. Several saliva substitutes were able to reduce enamel erosion significantly by 60-90% (in the range of the positive control). The protective potential of these products was in the range of the positive control (reduction of enamel loss to 30% of negative control). The erosion-protective potential of these high-viscous products is probably related to their film-forming properties, leading to a mechanical protection of the surface., Conclusion: Saliva substitutes containing a very low pH exhibit a distinct erosive potential, while most high-viscous products present an erosion-protective effect. It can be recommended that patients suffering from xerostomia and at high risk for dental erosion should use high-viscous saliva substitutes, but should avoid saliva substitutes with low pH or containing citric acid., Clinical Significance: It can be recommended that patients suffering from xerostomia and at high risk for dental erosion should use high-viscous saliva substitutes, but should avoid saliva substitutes with low pH or containing citric acid., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objectives: This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group., Materials and Methods: Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million loadings, 49N at 1.7Hz; 3000 thermocycles 5/50°C). Each of the 11 groups consisted of 12 specimens and 12 enamel antagonists. Quantitative analysis of wear was carried out with a 3D-surface analyser. Gloss and roughness measurements were evaluated using a glossmeter and an inductive surface profilometer before and after abrasive toothbrushing of machine-polished specimens. Additionally Martens hardness was measured. Statistically significant differences were calculated with one-way ANOVA (analysis of variance)., Results: Statistically significant differences were found for two-body wear, gloss, surface roughness and hardness. Zirconium dioxide ceramics showed no material wear and low wear of the enamel antagonist. Two-body wear of CAD/CAM-silicate and -lithium disilicate ceramics, -hybrid ceramics and -nanocomposite as well as direct nanocomposite did not differ significantly from that of human enamel. Temporary polymers showed significantly higher material wear than permanent materials. Abrasive toothbrushing significantly reduced gloss and increased roughness of all materials except zirconium dioxide ceramics. Gloss retention was highest with zirconium dioxide ceramics, silicate ceramics, hybrid ceramics and nanocomposites. Temporary polymers showed least gloss retention. Martens hardness differed significantly among ceramics, between ceramics and composites, and between resin composites and acrylic block materials as well., Conclusions: All permanent aesthetic CAD/CAM block materials tested behave similarly or better with respect to two-body wear and toothbrushing wear than human enamel, which is not true for temporary polymer CAD/CAM block materials. Ceramics show the best gloss retention compared to hybrid ceramics, composites and acrylic polymers., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: The authors conducted an in vitro study to investigate the influence of several internal bleaching regimens on the composite-to-composite shear bond strength of a dental core buildup material., Methods: The authors fabricated 72 specimens from a resin-based composite core buildup and assigned them randomly to six groups (four experimental and two control groups) (n = 12 per group), according to the following bleaching agents: sodium perborate mixed with distilled water (SP/W); sodium perborate mixed with 3 percent hydrogen peroxide (SP/HP-3); sodium perborate mixed with 30 percent hydrogen peroxide (SP/HP-30); 35 percent hydrogen peroxide (HP-35). After the 12-day bleaching procedures, the authors applied a calcium hydroxide dressing for two weeks. The two control groups consisted of unbleached specimens that either did not receive (C1) or did receive (C2) the calcium hydroxide dressing. The authors cleaned and silanized the resin-based composite specimens and coated them with an intermediate adhesive resin before applying fresh composite material. They measured composite surface roughness and shear bond strength and performed statistical analyses of the data., Results: Unbleached specimens in groups C1 and C2 exhibited significantly lower composite-to-composite bond strength and significantly lower surface roughness than did specimens in groups SP/W and SP/HP-3. Bond strength in group HP-35 was significantly lower than that in group SP/W., Conclusion: Internal bleaching regimens that involve the use of sodium perborate mixed with water or 3 percent hydrogen peroxide might increase the composite-to-composite interfacial bond strength., Clinical Implications: None of the internal bleaching regimens in this study had an adverse effect on the composite-to-composite interfacial bond strength.

Objective: To compare the protective potential of a conventional adhesive, a caries infiltrant and a combination of both against acidic challenge in vitro., Methods: One-hundred-and-fifty discs from bovine lower central incisors were fabricated. Seventy-five samples remained untreated, whereas the other half was subjected to a demineralisation process (14 days, acidic buffer, and pH 5) to create artificial enamel lesions. Specimens were then radioactively irradiated, and each 15 sound and demineralised specimens were treated with a caries infiltrant (Icon, DMG), an unfilled adhesive (Heliobond, IvoclarVivadent) or a combination of infiltrant and adhesive. Specimens treated with the adhesive followed by a flowable composite (TetricEvoFlow, IvoclarVivadent) served as positive control, while untreated specimens served as negative control. All samples were then subjected to lactic acid for 3 weeks at pH 4. Loss of apatite was determined using the radiochemical method of liquid scintillation. Data were statistically analysed by Kruskal-Wallis-test, one-way ANOVA and Scheffe's post hoc tests (p ≤.05)., Results: In both sound enamel and artificial caries lesions, untreated specimens showed the highest rate of apatite loss, whereas enamel treated with the adhesive and the flowable composite showed almost complete protection surface against dissolution. The caries infiltrant, the adhesive and the combination of both were able to decrease enamel dissolution, but the adhesive and the combination of adhesive and infiltrant were more effective than the infiltrant alone., Conclusion: Within the limitations of this in vitro study, the application of an adhesive (alone or in combination with the caries infiltrant) is more effective to protect enamel dissolution than the infiltrant alone., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objective: To test sealants to prevent erosive tooth wear caused by extrinsic and intrinsic acids under long-term exposition., Methods: 144 bovine enamel samples were randomly allocated to twelve groups (1-12). Samples of groups 1, 5 and 9 remained unsealed (positive controls), 2, 6 and 10 were sealed with Silicon Seal Nano Mix and 3, 7 and 11 with Seal&Protect. Groups 4, 8 and 12 were sealed with flowable composite (negative controls). Groups 1-4 were immersed in artificial saliva, 5-8 in hydrochloric acid and groups 9-12 in citric acid for 28 days, respectively. After 1, 2, 4, 7, 11, 14, 21 and 28 days, solutions were renewed and enamel wear was quantified by assignation of (32)P in the solutions., Results: In all immersion solutions, lowest mineral loss was observed for the negative controls whilst highest loss was observed for unsealed positive controls. In artificial saliva and citric acid, the loss from samples sealed with Seal&Protect was not significantly different compared with negative controls whilst loss in groups sealed with Silicon Seal Nano Mix was significantly higher. In hydrochloric acid, loss from samples sealed with Seal&Protect was not different compared with that of negative controls up to 4 days. Except day 1, the mineral loss in the Seal&Protect group was significantly lower compared with that of the Silicon Seal Nano Mix group., Conclusion: The tested resin based surface sealant is able to significantly reduce the erosive demineralisation of enamel caused by hydrochloric and citric acid even under long-term exposition., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Objectives: This study evaluated the effect of different surface conditioning methods on the tensile bond strength (TBS) and integrity of the amalgam-resin composite interface, using commercially available restoration repair systems., Methods: One hundred and sixty Gamma 2 amalgam specimens were stored in artificial saliva for 2 weeks and then randomly assigned to one of the following conditioning groups (n=20/group): Group 1: air abrasion, alloy primer and 'Panavia 21', Group 2: air abrasion and 'Amalgambond Plus', Group 3: air abrasion and 'All-Bond 3', Group 4: diamond bur, alloy primer and 'Panavia 21', Group 5: diamond bur and 'Amalgambond Plus', Group 6: diamond bur and 'All-Bond 3', Group 7: silica coating technique, and Group 8: non-conditioned amalgam surfaces (control group). Subsequently, resin composite material was added to the substrate surfaces and the amalgam-resin composite specimens were subjected to TBS testing. Representative samples from the test groups were subjected to scanning electron microscopy and surface profilometry. The data was analysed statistically with one-way ANOVA and post hoc Tukey's tests (α=0.05)., Results: The mean TBS of amalgam-resin composite ranged between 1.34 and 5.13MPa and varied with the degree of amalgam surface roughness and the type of conditioning technique employed. Significantly highest TBS values (5.13±0.96MPa) were obtained in Group 1 (p=0.013)., Conclusion: Under the tested conditions, significantly greater tensile bond strength of resin composite to amalgam was achieved when the substrate surface was conditioned by air abrasion followed by the application of the Panavia 21 adhesive system., Clinical Significance: Effecting a repair of an amalgam restoration with resin composite via the use of air abrasion and application of Panavia 21 would seem to enhance the integrity of the amalgam-resin composite interface. Clinical trials involving the implementation of this technique are indicated to determine the usefulness of this technique., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Background: The authors conducted an in vitro study to investigate the influence of various curing protocols on subsurface microhardness of dual-cured resin-based composites., Methods: The authors filled molds with four dual-cured resin-based composite core buildup materials: Clearfil DC Core Automix (Kuraray, Tokyo), Core•X flow (Dentsply DeTrey, Konstanz, Germany), LuxaCore Z-Dual (DMG, Hamburg, Germany) and MultiCore Flow (Ivoclar Vivadent, Schaan, Liechtenstein). They light cured the specimens for 20 or 60 seconds immediately after the filling procedure (time delay, 0 seconds) or after a 90-or 300-second delay. Self-cured specimens served as controls. The authors tested 15 specimens in each group. They measured the Knoop hardness number (KHN) at depths of 0.25, 2.00 and 5.50 millimeters two weeks after the initiation of polymerization., Results: Light curing with Core•X flow, LuxaCore Z-Dual and MultiCore Flow did not result in significantly higher KHNs at any depth compared with those for the self-cured control specimens. For Clearfil DC Core Automix, immediate light curing for 60 seconds resulted in significantly higher KHNs than those for self-cured specimens only at a depth of 5.50 mm (P=.0171). The study results showed no significant differences in KHN at different depths for Core•X flow specimens, independent of the curing protocol. All other materials exhibited a significant decrease in KHN at increased depths in only one of the six light-cured groups., Conclusion: The results of this study show that photoactivation of the tested dual-cured materials provided no clinically relevant benefit compared with self-curing with regard to the degree of microhardness., Clinical Implications: The dominant self-curing mode allows placement of the tested buildup materials in areas inaccessible to a curing light., (Copyright © 2011 American Dental Association. All rights reserved.)

Objective: Resin infiltration is considered as a treatment option for initial caries lesions. As cavitated early lesions might require additional restorative intervention, a caries infiltrant might be also used for enamel conditioning prior to composite insertion. This study aimed to analyse the shear bond strength of a flowable composite to sound and demineralised enamel pretreated with a caries infiltrant, a conventional adhesive or a combination of both., Methods: Flattened bovine enamel specimens (n=120) were either demineralised (14 d, acidic buffer, pH 5) or remained untreated. Sound and demineralised specimens (each n=20) were then treated with: (1) 35% phosphoric acid, conventional adhesive, (2) 15% hydrochloric acid, caries infiltrant or (3) 15% hydrochloric acid, caries infiltrant, conventional adhesive. Shear bond strength of a flowable composite was tested after 24 h water storage (37°C) and statistically analysed (ANOVA, p≤0.05). The mode of failure was assessed microscopically at 25× magnification., Results: On demineralised enamel, the combination of caries infiltrant and conventional adhesive showed significantly higher shear bond strength values than the conventional adhesive alone, while both being not significantly different from group 2. No significant differences between the groups could be detected on sound specimens. A higher percentage of cohesive failures could be observed in demineralised samples of group 2 (40%) and 3 (65%), while all other specimens presented almost only adhesive failures., Conclusion: The use of a caries infiltrant before application of a conventional adhesive did not impair bonding to sound and demineralised enamel and might be beneficial as a pretreatment in demineralised enamel., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Introduction: Pulpal diagnostics might be improved by using molecular markers found in dentinal fluid. In the current pilot study, we tested whether matrix metallopeptidase 9 (MMP-9) levels in dentinal fluid were detectable and differed between pulps from symptomatic teeth diagnosed with irreversible pulpitis and healthy counterparts., Methods: Thirty-one patients participated; 19 were diagnosed with irreversible pulpitis, and 12 were in need of replacement of a filling close to the pulp space in a clinically healthy tooth. Dentinal fluid was collected during a period of 2 minutes from dentin cavities by using folded polyvinylidene difluoride (PVDF) membranes, which were then transferred to microcentrifugation tubes containing physiologic saline solution. Total MMP-9 levels in these solutions were assessed by using a human MMP-9 fluorescent assay, detection limit 0.25 ng/mL. MMP-9 levels between groups were compared by using Mann-Whitney U test (alpha <0.05)., Results: Three specimens from the symptomatic teeth were not included because coronal pulps proved to be necrotic on access. Dentinal fluid samples from symptomatic teeth had significantly higher MMP-9 levels than those from clinically healthy counterparts (P < .05). However, merely 7 of the 16 pulpitis samples contained detectable levels of MMP-9. None of the clinically healthy control specimens contained any detectable amounts of MMP-9., Conclusions: With a sensitive assay, it was possible to detect an enzyme linked with pulp tissue destruction (MMP-9) in dentinal fluid. However, the collection method needs to be improved to provide predictable fluid yields. Longitudinal studies should be performed to assess the predictive value of molecular markers in dentinal fluid on pulpal pathosis., (Copyright © 2011 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to evaluate the effects of chemical activation of hydrogen peroxide (HP) gel on colour changes and penetration through the tooth structure., Methods: One hundred and four bovine incisors were used. One dentine (CD) disc and one enamel-dentine (ED) disc were prepared from each tooth. They were positioned over artificial pulpal chambers and the bleaching was performed with an experimental 35% HP gel. Two control and six experimental groups were prepared. In the positive control group (PC) no chemical activator was used. In the negative control group (NC) the specimens did not receive any bleaching. Each experimental group received a different chemical activator (manganese gluconate-MG; manganese chlorite-MC; ferrous sulphate-FS; ferrous chlorite-FC; and mulberries root extract-MRE). After the bleaching procedure a sample of solution was collected from the artificial pulpal chamber and the HP concentration was measured. The data were analysed using ANOVA, Tukey's, and Dunnett's tests., Results: The groups MG and FS showed a significantly lower penetration of HP than the PC group. For the parameter Delta E, all the groups, with the exception of the group MRE, showed a significantly higher means in relation to the PC group in ED colour. For dentine colour, just the groups MG and FS had significant differences in relation to PC., Conclusions: The addition of MG and FS decreases the penetration of HP. The chemical activation using metal salts tested was effective in increasing the bleaching effect., (Copyright 2010 Elsevier Ltd. All rights reserved.)

Introduction: This study evaluated the prepared surface areas of oval-shaped canals in distal roots of mandibular molars using four different instrumentation techniques., Methods: Teeth were prescanned and reconstructed using micro-computed tomography (MCT) scans at low resolution (68 microm). Forty-eight molars with ribbon-shaped/oval distal root canals were selected and randomly assigned to four groups. Distal canals (n = 12 each) were prepared by circumferential filing using Hedström files to apical size #40 (group H/CF); with ProTaper nickel-titanium rotaries to finishing file 4 (F4) considering the distal canal as 1 canal (group PT/1); ProTaper to F4 considering buccal and oral aspects of the distal canal as 2 individual canals (group PT/2); ProTaper to F4 in a circumferential filing motion (PT/CF). Before and after shaping, teeth were evaluated using MCT at 34-microm resolution. The percentage of prepared surface was assessed for the full canal length and the apical 4 mm. Statistical analysis was performed using analysis of variance and Bonferroni/Dunn multiple comparisons., Results: Preoperatively, canal anatomy was statistically similar among the groups (p = 0.56). Mean (+/- standard deviation) untreated areas ranged from 59.6% (+/-14.9, group PT/2) to 79.9% (+/-10.3, PT/1) for the total canal length and 65.2% to 74.7% for the apical canal portion, respectively. Canals in group PT/1 had greater untreated surface areas (p < 0.01) than groups PT/2 and PT/CF. Among all groups, amounts of treated surface areas were statistically similar in the apical 4 mm., Conclusions: Preparations of oval-shaped root canals in mandibular molars left a variable portion of surface area unprepared regardless of the instrumentation technique used. However, considering oval canals as two separate entities during preparation appeared to be beneficial in increasing overall prepared surface., (Copyright (c) 2010 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: The aim of this study was to investigate the effects of erosion and toothbrush abrasion on different restorative materials and human enamel., Methods: Human enamel and 5 kinds of tooth-colored restorative materials were used. The restorative materials included three composite resins (Filtek Silorane, Tetric EvoCeram, and Tetric EvoFlow), a polyacid-modified composite (Dyract Extra), and a conventional glass-ionomer cement (Ketac Fil Plus). For each type of the material, 40 specimens were prepared and embedded in ceramic moulds and divided into four groups (n=10): control group (C), erosion group (E), abrasion group (A), and erosion-abrasion group (EA). The specimens were subjected to six daily erosive attacks (groups E and EA; citric acid, pH 2.3, 1 min) and/or six abrasive attacks (groups A and EA; toothbrush abrasion, 100 strokes, 1 min), while the control specimens (group C) were maintained in artificial saliva. After 10-day treatment, the substance loss and surface changes were determined by surface profilometry and scanning electron microscopy., Results: Human enamel presented higher substance loss when compared to restorative materials. Generally, combined erosion-abrasion (EA) caused the highest substance loss, followed by erosion, abrasion, and storage in artificial saliva. Composite resin presented highest durability under erosive and/or abrasive attacks. Enamel and restorative materials showed degradation in groups E and EA through SEM observation., Conclusions: Toothbrush abrasion has a synergistic effect with erosion on substance loss of human enamel, polyacid-modified composite and glass-ionomer cement. The acid- and abrasive-resistance of human enamel was lower compared to restorative materials.