Social perception of children with and without caries.

AIM: Aim of this study was to analyse and compare the social perception of children with healthy teeth, visible dental caries and visible dental treatments by children (with and without caries experience) and their parents. METHODS: Images of three children (healthy teeth; untreated dental caries; treated caries i.e. restorations and missing teeth as consequence of caries treatment) were presented to fourto nine-years-old children with (n = 92) or without caries experience (n = 88) and their parents. The social perception was measured with a standardised interview (children) and a standardised questionnaire (parents). The results were statistically analysed by Wilcoxon signed-rank, Wilcoxon ranksum and chi-squared-tests (p < 0.05). CONCLUSION: Children and adults perceived children with (un)treated visible dental caries less positively than children with healthy teeth.

Material properties and bioactivity of a resin infiltrant functionalized with polyhedral oligomeric silsesquioxanes.

OBJECTIVES: To investigate the effect of methacrylate polyhedral oligomeric silsesquioxanes (POSS-8) on various material properties and mineral precipitation potential of a resin infiltrant. METHODS: A TEGDMA-based resin infiltrant was mixed with 0.5, 1, 3, 5 or 10 wt% POSS-8 or left unchanged (control). Degree of conversion (DC), water sorption (WS), viscosity, elastic modulus (E-modulus), flexural strength (FS), Knoop microhardness (KHN) and softening ratio (SR) were assessed. Growth of calcium phosphate (Ca/P) precipitates infiltrant-treated bovine enamel and dentin specimens immersed in artificial saliva or artificial dentinal fluid, respectively, for 28 days was analyzed by scanning electron microscopy and energy-dispersive X-ray spectroscopy. For viscosity assessment, pure TEGDMA filled with 0-10 wt% POSS-8 was used. Statistical analyses were performed using ANOVA and Tukey's post-hoc tests (p < 0.05). RESULTS: POSS-8 did not change the flexural strength, water sorption and softening ratio. The apparent degree of conversion was increased at lower concentrations only while E-modulus remained constant in almost all groups. The particles led to a slight decrease of KHN at concentrations below 3%. The effect on viscosity is comparable to the reinforcement effect. Ca/P precipitates formed on dentin specimens treated with POSS-8-filled infiltrant after 4 weeks of immersion, but were not detected on the control infiltrant. The mineral precipitation on enamel was not improved by POSS-8. SIGNIFICANCE: POSS-8 particles did not worsen the material properties of the resin infiltrant, while the Ca/P precipitation on dentin was stimulated.

Retrospective study on risk factors for repeated dental treatment of children under general anaesthesia.

AIM: This retrospective study aimed to evaluate potential risk factors predicting repeated dental treatment of children under general anaesthesia. MATERIALS AND METHODS: Children below 12 years of age receiving at least one dental treatment under general anaesthesia between 03/2010 and 10/2018 were analysed (n = 935, mean age: 4.6 ± 2.4). Dental records were analysed retrospectively for anamnestic, demographic, oral health and treatment factors. Kaplan-Meier statistics was used to estimate the time to second dental treatment under general anaesthesia. Potential risk factors for repeated dental treatment underwent univariate analysis using log-rank tests and were then submitted to a multi-variate Cox-regression analysis (a = 5%). RESULTS: One hundred fifteen children (12.3%) received or were planned to receive repeated dental treatment under general anaesthesia. In children receiving repeated dental treatment, the time intervals between first and second general anaesthesia and second and third general anaesthesia amounted to 22 ± 18 and 23 ± 20 months, respectively. The use of fluoridated toothpaste (HR: 0.28, p < 0.01) and attending 2 or more recall appointments per year (HR: 0.6, p < 0.01) significantly decreased the risk for repeated dental treatment under general anaesthesia in the multivariate model. CONCLUSION: Adherence to preventive recall appointments and to oral hygiene recommendations is essential to maintain oral health and avoid repeated dental treatment under general anaesthesia.

Repair Surface Conditioning Measures Affect Enamel and Dentin Bond Strength.

CLINICAL RELEVANCE: Contamination of enamel and dentin with repair surface conditioning measures should be avoided. SUMMARY: Objectives: To analyze whether the contamination with different repair conditioning measures impairs the adhesive performance of a universal adhesive applied in etch-and-rinse mode (ER) or self-etch mode (SE).Methods and Materials: Bovine enamel and dentin surfaces (each subgroup n=16) were bonded with a universal adhesive in ER or SE after contamination with different repair conditioning measures (sandblasting, silica coating, hydrofluoric acid etching, self-etching ceramic primer). In half of the groups, sand-blasting, silica coating, and hydrofluoric acid etching was followed by the use of a universal primer. If the universal adhesive was applied in ER, contamination was performed either before or after phosphoric acid etching. If the universal adhesive was applied in SE, bonding was performed after contamination. In the control groups, no contamination was simulated. Shear bond strength (SBS) and failure modes of composite buildups were determined after thermal cycling (10,000 cycles, 5°C-55°C). Statistical analysis was performed using analyses of variance, Weibull statistics, and χ2 tests (p<0.05).Results: In ER, sandblasting and silica coating significantly reduced SBS (control: enamel =25.7±4.2 MPa; dentin = 22.0±5.3 MPa) only when performed after phosphoric acid etching. Contamination with hydrofluoric acid impaired SBS on enamel but not on dentin. The self-etching ceramic primer reduced SBS, but not significantly. The contamination with the universal primer had no significant effect. In SE, all repair conditioning measures except the universal primer reduced SBS (control: enamel = 20.3±5.5 MPa; dentin = 23.0±4.0 MPa).Conclusion: Contamination of enamel and dentin by repair conditioning measures potentially affects bond strength.

How to intervene in the caries process: proximal caries in adolescents and adults-a systematic review and meta-analysis.

OBJECTIVES: For an ORCA/EFCD consensus, this systematic review assessed the question "How to intervene in the caries process in proximal caries in adolescents and adults". MATERIAL AND METHODS: Separating between the management of initial and cavitated proximal caries lesions, Medline via PubMed was searched regarding non-operative/non-invasive, minimally/micro-invasive and restorative treatment. First priority was systematic reviews or randomized controlled trials (RCTs), otherwise cohort studies. After extraction of data, the potential risk of bias was estimated depending on the study type, and the emerging evidence for conclusions was graded. RESULTS: Regarding non-invasive/non-operative care (NOC), no systematic reviews or RCTs were found. In cohort studies (n = 12) with a low level of evidence, NOC like biofilm management and fluoride was associated with a low proportion and slow speed of progression of initial proximal lesions. Minimally/micro-invasive (MI) treatments such as proximal sealants or resin infiltration (four systematic reviews/meta-analyses) were effective compared with a non-invasive/placebo control at a moderate level of evidence. Data on restorative treatment came with low evidence (5 systematic reviews, 13 RCTs); with the limitation of no direct comparative studies, sample size-weighted mean annual failure rates of class II restorations varied between 1.2 (bulk-fill composite) and 3.8% (ceramic). Based on one RCT, class II composite restorations may show a higher risk of failure compared with amalgam. CONCLUSIONS: Proximal caries lesions can be managed successfully with non-operative, micro-invasive and restorative treatment according to lesion stage and caries activity. CLINICAL RELEVANCE: Proximal caries treatment options like non-operative, micro-invasive and restorative care should be considered individually.

Micro-CT evaluation of sonically and ultrasonically activated irrigation on the removal of hard-tissue debris from isthmus-containing mesial root canal systems of mandibular molars.

AIM: To evaluate the efficacy of sonically and ultrasonically activated irrigation on removal of accumulated hard-tissue debris (AHTD) in mesial root canal systems of mandibular molars using micro-computed tomographic (micro-CT) analysis. METHODOLOGY: Forty mesial roots of mandibular molars with two independent canals joined apically by an isthmus (Vertucci type II) were selected. The root canals were instrumented using Reciproc R25 instruments, and specimens were scanned at a resolution of 10.5 µm. Subsequently, n = 10 roots were assigned to each of the four final irrigation groups such that the group means and variances were almost identical: sonically activated irrigation with EndoActivator (EA) or EDDY (ED), ultrasonically activated irrigation (UAI) and manual irrigation without activation (MI). The final irrigation procedures were performed using a total of 5 mL 1% NaOCl and 5 mL 15% EDTA per canal over 5 min with activation time of 4 × 20 s. Reconstructed data sets were coregistered, and the mean percentage reduction of AHTD after final irrigation was compared statistically between groups using analysis of variance at a significance level set at 5%. RESULTS: A significant reduction of AHTD was achieved after final irrigation in all groups (P < 0.05), ranging from 44.1% to 66.8%. The vol% of debris after irrigation was 3.7 ± 1.9% for EA, 3.3 ± 2.3% for ED, 2.1 ± 1.6% for UAI and 4.4 ± 2.3% for MI, with no significant difference between groups (P > 0.05). CONCLUSIONS: None of the final irrigation protocols completely removed AHTD from mesial root canal systems in extracted human mandibular molars. Sonically and ultrasonically activated irrigation performed no better compared to manual irrigation.

Association of depression with malnutrition, grip strength and impaired cognitive function among senior trauma patients.

BACKGROUND: Depression is common among senior adults, yet understudied among trauma patients. The purpose of this study was to assess the prevalence of depressive symptoms among seniors hospitalized in acute trauma care, to compare patients with depressive symptoms vs. those without, and to evaluate whether depression symptoms affects discharge destination. METHODS: This cross-sectional and prospective analysis was conducted among community-dwelling patients ≥70 years old, hospitalized at the Senior Trauma Center of the University Hospital Zurich, Switzerland. We used the Geriatric Depression Scale (GDS-15) to assess presence of depressive symptoms. Using a cutoff value of 5 points, we compared age- and gender-adjusted characteristics of patients with and without depressive symptoms. Multinomial logistic regression models were used to estimate the odds of returning home vs. not adjusting for age, gender, nutritional status, cognitive function and others. RESULTS: Of the 273 seniors enrolled, 104 (38.1%) were men and the mean age was 79.4 (SD = 6.5) years. We identified 52 (19.0%) patients with depressive symptoms. These patients were more likely to be older (p = 0.04), at risk for malnutrition (p<0.0001), at least pre-frail (p = 0.005), and have decreased cognitive function (p = 0.001). They were also more than twice as likely to be discharged to acute geriatric care compared to home (OR = 2.28 (CI = 1.12-4.68)). LIMITATIONS: Depressive symptoms were assessed during acute care without data before hospitalization. CONCLUSIONS: Senior trauma patients with depressive symptoms during acute care were more likely to be at higher risk of malnutrition, have cognitive decline and are more likely to receive additional geriatric care.

Effect of different scoring approaches upon credit assignment when using Multiple True-False items in dental undergraduate examinations.

INTRODUCTION: Various scoring approaches for Multiple True-False (MTF) items exist. This study aimed at comparing scoring results obtained with different scoring approaches and to assess the effect of item cues on each scoring approaches' result. MATERIALS AND METHODS: Different scoring approaches (MTF, Count-2, Count-3, "Vorkauf-Method," PS50 , Dichotomized MTF, "Blasberg-Method," Multiple response (MR), Correction for Guessing, "Ripkey-Method," Morgan-Method, Balanced Scoring Method) were retrospectively applied to all MTF items used within electronic examinations of undergraduate dental students at the University Medical Center Göttingen in the winter term 2016/2017 (1297 marking events). Item quality was evaluated regarding formal parameters such as presence of cues and correctness of content. Differences between scoring results of all scoring approaches and the differences between each methods' scoring results of items with and without cues were calculated by Wilcoxon rank sum tests (P < .05). RESULTS: Average scoring results per item highly differed between the scoring approaches and ranged from 0.46 (MR) to 0.92 (Dichotomized MTF). Presence of cues leads to significantly higher scoring in case of all scoring approaches (P < .001; +0.14 on average). However, effect of cues differed amongst scoring approaches and ranged from +0.04 (Dichotomized MTF) to +0.20 (MR). CONCLUSION: Scoring of MTF items is complex. The data presented in this manuscript may help educators make informed choices about scoring algorithms.

Efficacy of the ProTaper retreatment system in removing Thermafil, GuttaCore or vertically compacted gutta-percha from curved root canals assessed by micro-CT.

AIM: To evaluate ex vivo the efficacy of ProTaper Universal Retreatment files (Dentsply Sirona, Ballaigues, Switzerland) in removing Thermafil, GuttaCore (both Dentsply Sirona) or vertically compacted gutta-percha from curved root canals using micro-CT. METHODOLOGY: Sixty curved molar roots with the same mean canal curvatures and radii in two directions were prepared using ProFile instruments (Dentsply Sirona) to size 30 with .04 taper and obturated with either Thermafil, GuttaCore or vertically compacted gutta-percha and AH Plus (n = 20). Specimens were retreated using the ProTaper Universal Retreatment files D1, D2 and D3 to working length, and root canal preparation was completed with ProTaper Next (Dentsply Sirona) to size ×4. Percentages of residual filling material and dentine removal were assessed using micro-CT imaging. Working time and procedural errors were recorded. Statistical analysis was performed using Kruskal-Wallis and Wilcoxon tests. RESULTS: No significant differences between carrier-based and warm vertical compaction regarding residual filling material (14.2-19.3%) and dentine removal (2.7-3.2 mm3 ) were detected (P > 0.05). Time to reach working length was significantly faster for canals filled with GuttaCore than that observed for Thermafil and warm vertical compaction (P < 0.05). Five lateral perforations with the D3 file occurred during retreatment, one in the Thermafil and four in the vertical compaction group. CONCLUSIONS: Remaining filling material and dentine removal were similar for all canal filling techniques. Regaining working length was significantly faster for GuttaCore compared with Thermafil and vertically compacted gutta-percha. Procedural errors occurred during retreatment of severely curved root canals with the ProTaper Universal Retreatment files in 5 of 60 canals (8%).

Moisture content of root canal dentine affects detection of microcracks using micro-computed tomography.

AIM: To evaluate the effect of moisture content in root canal dentine on detection of microcracks using micro-computed tomography. METHODOLOGY: Ten roots with and without craze lines or cracks (each n = 5) were selected and scanned six times with different moisture conditions of root dentine using a micro-CT scanner at a high resolution of 10.5 µm. Scanning conditions were as follows: (i) after 30-day wet storage, (ii) after 2-h dry time, (iii) after 48-h wet storage, (iv) after 24-h dry time, (v) after 48-h wet storage, (vi) after 2-h dry time. From each scan, cross-sectional images were obtained at intervals of 1 mm (total n = 708) and evaluated for the presence of dentinal microcracks twice by five calibrated blinded observers. Statistical analysis was performed by nonparametric analysis of variance for longitudinal data (P < 0.05). RESULTS: Intra-rater percentage agreement ranged between 92% and 98%, whereas inter-rater percentage agreement was 81% and 83%, respectively. No significant differences between all wet groups as well as between both groups with 2-h dry time were detected (P > 0.05). Almost no cracks were observed after wet storage with a significant increase of cracks after 2-h dry time (P < 0.001). Significantly more microcracks were identified after 24 h than after 2-h dry time (P < 0.004). CONCLUSIONS: Moisture content of dentine influenced detection of microcracks when evaluated using micro-CT. Scanning should be performed on dried specimens to allow reliable identification of dentinal defects. Formation of new cracks during dry periods up to 24 h was disproved.

Microleakage and Shear Bond Strength of Composite Restorations Under Cycling Conditions.

OBJECTIVES: The aim of this study was to evaluate microleakage and shear bond strength of composite restorations under different cycling conditions. METHODS AND MATERIALS: Class V cavities were prepared in the buccal and lingual surfaces of 30 human molars (n=60). A further 60 molars were used to prepare flat enamel and dentin specimens (n=60 each). Cavities and specimens were divided into six groups and pretreated with an adhesive (self-etch/Clearfil SE Bond or etch-and-rinse/Optibond FL). Composite was inserted in the cavities or adhered to the specimens' surfaces, respectively, and submitted to cycling (control: no cycling; thermal cycling: 10,000 cycles, 5°C to 55°C; thermal/erosive cycling: thermal cycling plus storage in hydrochloric acid pH 2.1, 5 minutes, 6×/day, 8 days). Microleakage was quantified by stereomicroscopy in enamel and dentin margins after immersion in silver nitrate. Specimens were submitted to shear bond strength testing. Statistical analysis was done by two-way analysis of variance and Kruskal-Wallis tests (p<0.05). RESULTS: Microleakage in enamel margins was significantly lower in the control group compared with thermal cycling or thermal/erosive cycling. Erosive conditions increased microleakage compared with thermal cycling (significant only for Clearfil SE Bond). No significant differences were observed in dentin margins. Bond strength of enamel specimens was reduced by thermal cycling and thermal/erosive cycling when Clearfil SE Bond was used and only by thermal/erosive cycling when Optibond FL was used. No differences were observed among dentin specimens. CONCLUSIONS: Thermal/erosive cycling can adversely affect microleakage and shear bond strength of composite resin bonded to enamel.

[How are Pediatric Hospitals in North-Rhine Westfalia Prepared to Overcome Language Barriers? A Pilot Study Exploring The Structural Quality of Inpatient Care]. / Wie sind Kinder- und Jugendkliniken in Nordrhein-Westfalen auf die Überwindung von Sprachbarrieren vorbereitet? ­ Eine Pilotstudie zur Strukturqualität in der stationären Gesundheitsversorgung.

Background In Germany, 35% of all children are considered to have a "migration background", and in the state of North-Rhine-Westfalia 43%. Frequently, one or both parents of a patient with a migration background have limited German language proficiency. Communication barriers due to a language difference can have a negative impact on quality of care, patient safety and costs of care. In this study, we investigate how children's hospitals are prepared to meet the challenges associated with language barriers. Methods We surveyed all children's hospitals in the state of North-Rhine-Westfalia, Germany. The questionnaire was based on the "Standards for Culturally and Linguistically Appropriate Services in Health and Health Care (CLAS)" and was adapted to circumstances in Germany. Results Thirty-eight hospitals participated (51%) in this survey. Language barriers occurred frequently (75% of respondents mentioned language difficulties in more than 10% of the patient population). 82% of respondents rated their hospital to be "less than well prepared" to overcome language barriers. In the majority of hospitals (62%), the need for an interpreter was determined on a case-to-case basis and not according to any set protocol. In most cases bilingual staff was used for interpreting. However, only 38% of respondents found a list of available bilingual staff to be a sufficient resource. 42% of respondents did not know the monthly costs for professional interpreting services. In the remaining cases, costs were less than € 500/month. Conclusion To overcome language barriers, hospitals rely on local resources. The majority of respondents did not find them to be appropriate and sufficient. The development of quality standards and the provision of financial resources are necessary to mobilize this potential for improvement. Therefore, other disciplines and sectors of healthcare need to be analyzed in order to provide the evidence for a constructive discussion with decision makers in policy and health insurance.

Fluoride gel supplemented with sodium hexametaphosphate reduces enamel erosive wear in situ.

OBJECTIVE: This study evaluated the effect of fluoride gels, supplemented or not with sodium hexametaphosphate (HMP), on enamel erosive wear in situ. METHODS: Twelve healthy volunteers wore palatal appliances containing four bovine enamel discs. Subjects were randomly allocated into four experimental phases (double-blind, crossover protocol) according to the gels: Placebo (no fluoride or HMP), 1% NaF, 2% NaF, and 1% NaF+9% HMP. Enamel discs were selected after polishing and surface hardness analysis, and treated only once with the respective gels prior to each experimental phase. Erosion (ERO) was performed by extra-oral immersion of the appliance in 0.05M citric acid, pH 3.2 (four times/day, five minutes each, 5 days). Additional abrasion (ERO+ABR) was produced on only two discs by toothbrushing with fluoridated dentifrice after ERO (four times/day, 30s, 5 days). The specimens were submitted to profilometry and hardness analysis. The results were analyzed by two-way ANOVA and the Student-Newman-Keuls test (p<0.05). RESULTS: The 1% NaF+9% HMP gel promoted significantly lower enamel wear for ERO compared to the other groups, being statistically lower than 1% NaF and Placebo for ERO+ABR. Similarly, the lowest values of integrated lesion area were found for 1% NaF+9% HMP and 2% NaF, respectively, for ERO and ERO+ABR. CONCLUSION: The addition of HMP to the 1% NaF gel promoted greater protective effect against ERO and ERO+ABR compared to the 1% NaF gel, achieving similar protective levels to those seen for the 2% NaF gel. CLINICAL SIGNIFICANCE: Gel containing 1% NaF+9% HMP showed a high anti-erosive potential, being a safer alternative when compared to a conventional 2% NaF gel.

Consensus report of the European Federation of Conservative Dentistry: erosive tooth wear--diagnosis and management.

OBJECTIVE: Due to an increased focus on erosive tooth wear (ETW), the European Federation of Conservative Dentistry (EFCD) considered ETW as a relevant topic for generating this consensus report. MATERIALS AND METHODS: This report is based on a compilation of the scientific literature, an expert conference, and the approval by the General Assembly of EFCD. RESULTS: ETW is a chemical-mechanical process resulting in a cumulative loss of hard dental tissue not caused by bacteria, and it is characterized by loss of the natural surface morphology and contour of the teeth. A suitable index for classification of ETW is the basic erosive wear examination (BEWE). Regarding the etiology, patient-related factors include the pre-disposition to erosion, reflux, vomiting, drinking and eating habits, as well as medications and dietary supplements. Nutritional factors relate to the composition of foods and beverages, e.g., with low pH and high buffer capacity (major risk factors), and calcium concentration (major protective factor). Occupational factors are exposition of workers to acidic liquids or vapors. Preventive management of ETW aims at reducing or stopping the progression of the lesions. Restorative management aims at reducing symptoms of pain and dentine hypersensitivity, or to restore esthetic and function, but it should only be used in conjunction with preventive strategies. CONCLUSIONS: Effective management of ETW includes screening for early signs of ETW and evaluating all etiological factors. CLINICAL RELEVANCE: ETW is a clinical condition, which calls for the increased attention of the dental community and is a challenge for the cooperation with other medical specialities.

A comparison of upper and lower body energetics during high-intensity exercise.

AIM: The aim of the present study was to measure and compare the aerobic, anaerobic alactic and anaerobic lactic energy system contribution during the 30-sec Wingate anaerobic test (WAnT) for the upper and lower body within the same individuals. METHODS: Physically active men (N.=14) completed two WAnTs on an electronic arm ergometer and a cycle ergometer separated by three days. A fly wheel braking force corresponding to 5% and 7.5% of the participants body weight was used for the upper and lower body WAnTs respectively. Oxygen uptake and blood lactate were measured before, during and after both WAnTs, and body composition was measured using dual-energy X-ray absorptiometry (DEXA). RESULTS: The anaerobic lactic energy system contribution was significantly (P<0.01) higher during the upper body (60.3±5.6%) compared to the lower body (46.9±6.9%) WAnT. The contribution of the anaerobic alactic system was significantly higher (P<0.01) during the lower body (36.5±6.3%) compared to the upper body (28.3±4.9%) WAnT, with the aerobic system contribution significantly (P<0.05) higher for the lower body (16.8±2.5%) compared to the upper body (11.4±1.4%) WAnT. CONCLUSION: The anaerobic lactic energy system provides over 60% of the energy requirements during an upper body WAnT but provides less the 50% during the lower body WAnT. In contrast, the aerobic and anaerobic alactic energy system contribution was significantly less for the upper body WAnT compared to the lower body WAnT.

Effect of different matrix metalloproteinase inhibitors on microtensile bond strength of an etch-and-rinse and a self-etching adhesive to dentin.

AIM: This study aimed to analyze the effect of different matrix metalloproteinase (MMP) inhibitors on the microtensile bond strength (microTBS) of an etch-and-rinse and a self-etching adhesive after 9 months of aging. METHODS AND MATERIALS: Flat human dentin surfaces were bonded either with an etch-and-rinse adhesive (Optibond FL) or a self-etching adhesive (Clearfil SE Bond). Dentin surfaces were left untreated or were pretreated with MMP inhibitors (2% chlorhexidine digluconate [CHX], 0.05% green tea extract, 1 mM ferrous sulfate, or 0.2 mM galardin) prior to application of the adhesive. Composite buildups were made incrementally. Pretreated groups were tested after 9 months of storage in artificial saliva (37°C) and compared with untreated groups, which were tested immediately (initial microTBS) and upon aging (9-month microTBS). Data were analyzed by linear mixed-model regression. Failure mode analysis was performed microscopically and statistically analyzed by repeated-measures analysis of variance (p<0.05). RESULTS: MicroTBS of the etch-and-rinse adhesive but not of the self-etching adhesive was significantly decreased by aging. For Optibond FL, pretreatment with 2% CHX, 0.05% green tea extract, and 0.2 mM galardin revealed bond strength values (MPa) similar to the initial microTBS (32.1±14.8) and significantly higher compared with the microTBS (20.3±13.6) of aged untreated dentin. No significant differences were observed between groups bonded with Clearfil SE Bond (initial microTBS: 28.3±12.4; 9-month microTBS: 25.3±11.8). Application of the MMP inhibitors decreased the number of adhesive failures compared with untreated controls after 9 months of aging, but this effect was not significant. CONCLUSION: The MMP inhibitors prevented the decrease in microTBS upon aging of the etch-and-rinse but not of the self-etching adhesive.

Stability against brushing abrasion and the erosion-protective effect of different fluoride compounds.

This study aimed to analyse the impact of brushing on the protective effect of different fluoride solutions on enamel and dentin erosion. Bovine enamel and dentin specimens were rinsed once with TiF4, AmF, SnF2 (0.5 M F, 2 min) or water (control). Specimens were either left unbrushed or brushed with 10, 20, 50, 100 or 500 brushing strokes in an automatic brushing machine (2 N, non-fluoridated toothpaste slurry). Ten specimens per group were eroded with hydrochloric acid (HCl) (pH 2.3) for 60 s, and calcium release into the acid was determined by atomic absorption spectroscopy. Additionally, enamel and dentin surfaces were analysed by X-ray energy-dispersive spectroscopy (EDS) (n = 6/group) and scanning electron microscopy (SEM) (n = 2/group) before brushing and after 500 brushing strokes. Statistical analysis (p < 0.05) was performed by three- and one-way ANOVA (calcium release) or repeated measures ANOVA (EDS). TiF4, AmF and SnF2 reduced the erosive calcium loss in unbrushed specimens to 58-67% (enamel) and 23-31% (dentin) of control. Calcium release increased with increasing brushing strokes prior to erosion and amounted to 70-88% (enamel) and 45-78% (dentin) of control after 500 brushing strokes. Brushing reduced the surface concentration of fluoride (AmF), tin (SnF2) and titanium (TiF4). SEM revealed that surface precipitates were affected by long-term brushing. Brushing reduced the protective potential of TiF4, AmF and SnF2 solutions. However, considering a small number of brushing strokes, the protective effect of fluoride solutions is only slightly affected by brushing abrasion.

Impact of different fluoride concentrations and pH of dentifrices on tooth erosion/abrasion in vitro.

BACKGROUND: This in vitro study analysed the effect of different fluoride concentrations in acidic or neutral liquid dentifrices in protecting enamel and dentine from erosive and abrasive wear. METHODS: Bovine enamel and dentine specimens (n = 132) were randomly allocated to 11 groups (each n = 12): experimental liquid dentifrices with 550 ppm F, 1100 ppm F, 5000 ppm F or 0 ppm F/placebo (each at pH 4.5 and pH 7.0); and commercial dentifrices with 550 ppm F (Colgate Baby, pH 7.0), 1100 ppm F (Crest, pH 7.0) and 5000 ppm F (Duraphat, pH 7.0). The specimens were subjected to erosion for 90 seconds, 4 times/day, over 7 days. Immediately after the first and last erosion, the specimens were brushed for 15 seconds using one of the dentifrices. Tooth wear was measured profilometrically (µm) and analysed by ANOVA (p < 0.05). RESULTS: All fluoridated liquid dentifrices significantly reduced enamel wear compared to the placebo and commercial dentifrices. Only liquid dentifrices with 1100 and 5000 ppm F significantly reduced dentine wear compared to placebo dentifrice. The pH had no effect, but the consistency had a significant impact on the effect of dentifrices. CONCLUSIONS: Liquid dentifrices with high F concentration appear to be a good option to prevent tooth wear.

Effect of acidic solution viscosity on enamel erosion.

The objective of this in vitro study was to investigate the effects of viscosity changes of different acidic solutions on dental erosion. Bovine enamel samples (n = 240, Ø = 3 mm) were embedded in acrylic resin and were allocated to 30 groups (n = 8). Citric acid (CA) and phosphoric acid (PA) solutions at pH 2.5, 3, and 3.5 were prepared in de-ionized water (titratable acidity to pH 5.5: 31 ± 0.6 mmol OH(-)/l). The kinetic viscosities of the acidic solutions were adjusted to 1.5, 3, 6, 12, and 24 mm(2)/sec by the addition of hydroxypropyl cellulose (HPC) at different concentrations. Solutions were pumped over the enamel surface from a reservoir with a drop rate of 1 mL/min. Each specimen was eroded for 10 min at 20 °C. Erosion of enamel surfaces was measured by profilometry. Data were analyzed by analyses of variance and logarithmic regression analyses (p < 0.05). Enamel loss was dependent on viscosity, pH, and the kind of acid. The regression analyses showed that higher viscosity caused lower enamel erosion for both acids and all pH levels. Dental erosion is dependent not only on chemical factors of the acid, like pH and acid type, but also on acid viscosity.