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.

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.

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.

[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.

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.

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.

Different protocols to produce artificial dentine carious lesions in vitro and in situ: hardness and mineral content correlation.

This study compared dentine demineralization induced by in vitro and in situ models, and correlated dentine surface hardness (SH), cross-sectional hardness (CSH) and mineral content by transverse microradiography (TMR). Bovine dentine specimens (n = 15/group) were demineralized in vitro with the following: MC gel (6% carboxymethylcellulose gel and 0.1 M lactic acid, pH 5.0, 14 days); buffer I (0.05 M acetic acid solution with calcium, phosphate and fluoride, pH 4.5, 7 days); buffer II (0.05 M acetic acid solution with calcium and phosphate, pH 5.0, 7 days), and TEMDP (0.05 M lactic acid with calcium, phosphate and tetraethyl methyl diphosphonate, pH 5.0, 7 days). In an in situ study, 11 volunteers wore palatal appliances containing 2 bovine dentine specimens, protected with a plastic mesh to allow biofilm development. The volunteers dripped a 20% sucrose solution on each specimen 4 times a day for 14 days. In vitro and in situ lesions were analyzed using TMR and statistically compared by ANOVA. TMR and CSH/SH were submitted to regression and correlation analysis (p < 0.05). The in situ model produced a deep lesion with a high R value, but with a thin surface layer. Regarding the in vitro models, MC gel produced only a shallow lesion, while buffers I and II as well as TEMDP induced a pronounced subsurface lesion with deep demineralization. The relationship between CSH and TMR was weak and not linear. The artificial dentine carious lesions induced by the different models differed significantly, which in turn might influence further de- and remineralization processes. Hardness analysis should not be interpreted with respect to dentine mineral loss.

Impact of laminar flow velocity of different acids on enamel calcium loss.

OBJECTIVE: The aim of the study was to evaluate the impact of flow velocity under laminar flow conditions of different acidic solutions on enamel erosion. MATERIAL AND METHODS: A total of 240 bovine enamel specimens were prepared and allocated to 30 groups (n = 8 each). Samples of 18 groups were superfused in a flow chamber system with laminar flow behavior using 1 ml of citric acid or hydrochloric acid (HCl) of pH 2.0, 2.6 or 3.0. Flow rates in the sample chamber were adjusted to 10, 60 or 100 µl/min. To simulate turbulent flow behavior, samples of six groups were immersed in 1 ml of the respective solution, which was vortexed (15 min, 600 rpm). For simulating non-agitated conditions, specimens of the remaining six groups were immersed in 1 ml of the respective solution without stirring. Calcium in the solutions, released from the enamel samples, was determined using Arsenazo III method. RESULTS: For acidic solutions of pH 2.6 and 3.0, erosive potential of citric acid was equivalent to that of HCl at a flow of 100 µl/min. The same observation was made for the samples subjected to turbulent conditions at pH 3. At all other conditions, citric acid induced a significantly higher calcium loss than HCl. CONCLUSION: It is concluded that under slow laminar flow conditions, flow rate variations lead to higher erosive impact of citric acid compared to hydrochloric acid at pH 2.0, but not at pH ≥ 2.6 and increasing laminar flow or turbulent conditions. CLINICAL RELEVANCE: Erosive enamel dissolution under laminar flow conditions is a complex issue influenced by flow rate and acidic substrate.

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.

Treatment intensification does not reduce residual HIV-1 viremia in patients on highly active antiretroviral therapy.

In HIV-1-infected individuals on currently recommended antiretroviral therapy (ART), viremia is reduced to <50 copies of HIV-1 RNA per milliliter, but low-level residual viremia appears to persist over the lifetimes of most infected individuals. There is controversy over whether the residual viremia results from ongoing cycles of viral replication. To address this question, we conducted 2 prospective studies to assess the effect of ART intensification with an additional potent drug on residual viremia in 9 HIV-1-infected individuals on successful ART. By using an HIV-1 RNA assay with single-copy sensitivity, we found that levels of viremia were not reduced by ART intensification with any of 3 different antiretroviral drugs (efavirenz, lopinavir/ritonavir, or atazanavir/ritonavir). The lack of response was not associated with the presence of drug-resistant virus or suboptimal drug concentrations. Our results suggest that residual viremia is not the product of ongoing, complete cycles of viral replication, but rather of virus output from stable reservoirs of infection.

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.

Decision-making and treatment with respect to surgical intervention in the context of a European Core Curriculum in Cariology.

This paper is part of a series of papers towards a European Core Curriculum in Cariology for undergraduate dental students. The European Core Curriculum in Cariology is the outcome of a process starting in 2006 and culminating in a joint workshop of the European Organisation for Caries Research (ORCA) together with the Association for Dental Education in Europe (ADEE) which was held in Berlin from 27 to 30 June 2010. The present paper covers decision-making and treatment with respect to surgical intervention. In particular, it will provide some background information on this part of the European Core Curriculum. Undergraduate dental education should enable the student to become a competent, skilful and caring dentist who is able, upon graduation, to take professional responsibility for diagnosis, as well as effective safe, and long-lasting care in the best interests of the patient. With respect to decision-making around surgical intervention for dental caries, several factors have to be considered. These include, patient needs, preventive strategies, tooth preservation, caries management success and failure rates, as well as short-term and long-term treatment costs. With respect to surgical intervention, manual skills at a high level are required. This is of crucial importance for the graduating dentist allowed to practise dentistry in many EU countries.

Short-course raltegravir intensification does not reduce persistent low-level viremia in patients with HIV-1 suppression during receipt of combination antiretroviral therapy.

BACKGROUND: Combination antiretroviral therapy suppresses but does not eradicate human immunodeficiency virus type 1 (HIV-1) in infected persons, and low-level viremia can be detected despite years of suppressive antiretroviral therapy. Short-course (28-day) intensification of standard antiretroviral combination therapy is a useful approach to determine whether complete rounds of HIV-1 replication in rapidly cycling cells contribute to persistent viremia. We investigated whether intensification with the integrase inhibitor raltegravir decreases plasma HIV-1 RNA levels in patients receiving suppressive antiretroviral therapy. METHODS: Subjects (n = 10) with long-term HIV-1 suppression receiving combination antiretroviral regimens had their regimens intensified for 4 weeks with raltegravir. Plasma HIV-1 RNA level was determined before, during, and after the 4-week intensification period, using a sensitive assay (limit of detection, 0.2 copies of HIV-1 RNA/mL of plasma). A 4-week intensification course was chosen to investigate potential HIV-1 replication in cells with relatively short (approximately 1-14-day) half-lives. RESULTS: There was no evidence in any subject of a decline in HIV-1 RNA level during the period of raltegravir intensification or of rebound after discontinuation. Median levels of HIV-1 RNA before (0.17 log10 copies/mL), during (0.04 log10 copies/mL), and after (0.04 log10 copies/mL) raltegravir intensification were not significantly different (P > .1 for all comparisons in parametric analyses). High-performance liquid chromatography and mass spectroscopy experiments confirmed that therapeutic levels of raltegravir were achieved in plasma during intensification. CONCLUSIONS: Intensification of antiretroviral therapy with a potent HIV-1 integrase inhibitor did not decrease persistent viremia in subjects receiving suppressive regimens, indicating that rapidly cycling cells infected with HIV-1 were not present. Eradication of HIV-1 from infected persons will require new therapeutic approaches. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT00618371.

Effects of various fluoride solutions on enamel erosion in vitro.

The objective of this in vitro study was to investigate the effect of different fluoride solutions on enamel erosion. Human enamel specimens were pretreated with 1 of 10 different fluoride solutions (n = 20): TiF(4), NaF, AmF, ZnF(2), or SnF(2), each at native pH (pH range: 1.2-7.8) or buffered pH (pH = 4). The control group samples received no fluoride pretreatment. All samples were then eroded by citric acid (pH 2.6) for 6 x 1 min daily over 5 days. Between the erosive cycles, the samples were stored in artificial saliva. Erosion effects were investigated by surface profilometry (n = 10), scanning electron microscopy (n = 4), and energy-dispersive X-ray spectroscopy (n = 6) after fluoride pretreatment and after erosion. To test the effects of pH only, additional experiments were carried out with fluoride-free solutions at similar pH to that of fluoride solutions. In general, AmF solution was more effective in protecting enamel erosion compared to all other fluoride agents. However, the application of native TiF(4), native and buffered SnF(2), and native and buffered AmF solutions also resulted in significantly less enamel loss compared to the control group. A Ti-rich coating was formed after application of native TiF(4), but partially dissolved due to erosive attack. Samples pretreated with SnF(2) showed a significant increase in surface tin content. Surface fluoride concentration was significantly increased by native TiF(4), native and buffered AmF, buffered ZnF(2), and buffered NaF application. Under the current experimental setting, the fluoride agents at lower pH had better protective potential. Highly concentrated TiF(4), AmF, and SnF(2) solution was effective in inhibiting erosion of enamel.

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.

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.

Comparison of the effects of TiF4 and NaF solutions at pH 1.2 and 3.5 on enamel erosion in vitro.

This study aimed to analyse and compare the protective effect of buffered (pH 3.5) and native (pH 1.2) TiF(4) in comparison with NaF solutions on enamel erosion. Bovine samples were pretreated with 1.50% TiF(4) or 2.02% NaF (both 0.48 M F) solutions, each at a pH of 1.2 and 3.5. The control group received no fluoride pretreatment. Twenty samples per group were eroded with HCl (pH 2.6) for 10 x 60 s. Erosion was either investigated by profilometry (n = 10) or by determination of calcium release into the acid (n = 10). Additionally, the elemental surface composition was quantified by X-ray energy-dispersive spectroscopy in fluoridated but not eroded samples (6 samples per group). Scanning electron microscopy was performed prior and after erosion (2 samples per group). Cumulative enamel loss (mum) and calcium release (nmol/mm(2)) were analysed by repeated-measures ANOVA. The Ti and F surface composition was analysed by one-way ANOVA separately for each element. Only TiF(4) at pH 1.2 reduced enamel surface loss significantly. Calcium release was significantly reduced by TiF(4) and NaF at pH 1.2, but not by the solutions at pH 3.5. Samples pretreated with TiF(4) at pH 1.2 showed a significant increase in Ti, while NaF increased F concentration significantly. Only TiF(4) at pH 1.2 induced the formation of a glaze-like layer, which was still present after erosion. Enamel erosion can be significantly reduced by TiF(4) at pH 1.2 but not at pH 3.5. TiF(4) at pH 1.2 was more effective in protecting against enamel erosion than NaF.

Comparison of cross-sectional hardness and transverse microradiography of artificial carious enamel lesions induced by different demineralising solutions and gels.

The aims of this study were: (1) to correlate surface (SH) and cross-sectional hardness (CSH) with microradiographic parameters of artificial enamel lesions; (2) to compare lesions prepared by different protocols. Fifty bovine enamel specimens were allocated by stratified randomisation according to their initial SH values to five groups and lesions produced by different methods: MC gel (methylcellulose gel/lactic acid, pH 4.6, 14 days); PA gel (polyacrylic acid/lactic acid/hydroxyapatite, pH 4.8, 16 h); MHDP (undersaturated lactate buffer/methyl diphosphonate, pH 5.0, 6 days); buffer (undersaturated acetate buffer/fluoride, pH 5.0, 16 h), and pH cycling (7 days). SH of the lesions (SH(1)) was measured. The specimens were longitudinally sectioned and transverse microradiography (TMR) and CSH measured at 10- to 220-microm depth from the surface. Overall, there was a medium correlation but non-linear and variable relationship between mineral content and radicalCSH. radicalSH(1) was weakly to moderately correlated with surface layer properties, weakly correlated with lesion depth but uncorrelated with integrated mineral loss. MHDP lesions showed the highest subsurface mineral loss, followed by pH cycling, buffer, PA gel and MC gel lesions. The conclusions were: (1) CSH, as an alternative to TMR, does not estimate mineral content very accurately, but gives information about mechanical properties of lesions; (2) SH should not be used to analyse lesions; (3) artificial caries lesions produced by the protocols differ, especially considering the method of analysis.