The tongue biofilm metatranscriptome identifies metabolic pathways associated with the presence or absence of halitosis.

Intra-oral halitosis usually results from the production of volatile sulfur compounds, such as methyl mercaptan and hydrogen sulfide, by the tongue microbiota. There are currently no reports on the microbial gene-expression profiles of the tongue microbiota in halitosis. In this study, we performed RNAseq of tongue coating samples from individuals with and without halitosis. The activity of Streptococcus (including S. parasanguinis), Veillonella (including V. dispar) and Rothia (including R. mucilaginosa) was associated with halitosis-free individuals while Prevotella (including P. shahi), Fusobacterium (including F. nucleatum) and Leptotrichia were associated with halitosis. Interestingly, the metatranscriptome of patients that only had halitosis levels of methyl mercaptan was similar to that of halitosis-free individuals. Finally, gene expression profiles showed a significant over-expression of genes involved in L-cysteine and L-homocysteine synthesis, as well as nitrate reduction genes, in halitosis-free individuals and an over-expression of genes responsible for cysteine degradation into hydrogen sulfide in halitosis patients.

Biomineralization potential and biological properties of a new tantalum oxide (Ta2O5)-containing calcium silicate cement.

OBJECTIVE: The present study evaluated the biological effects and biomineralization potential of a new tantalum oxide (Ta2O5)-containing material designed for vital pulp therapy or perforation repair (NeoMTA 2), compared to NeoMTA Plus and Bio-C Repair. MATERIAL AND METHODS: Human dental pulp stem cells (hDPSCs) were exposed to different eluates from NeoMTA Plus, NeoMTA 2, and Bio-C Repair. Ion release from each material was determined using inductively coupled plasma-optical emission spectrometry (ICP-MS). The biological experiments performed were MTT assays, apoptosis/necrosis assays, adhesion assays, migration assays, morphology evaluation, and reactive oxygen species (ROS) production analysis. Biomineralization was assessed by Alizarin red S staining. Finally, osteo/odontogenic gene expression was determined by real-time quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR). Data were analyzed using one-way ANOVA followed by Tukey's multiple comparison test. RESULTS: NeoMTA 2 displayed a significantly higher calcium release compared to the other materials (p < 0.05). When hDPSCs were cultured in presence of the different material eluates, all groups exhibited similar hDPSC viability and migration rates when compared to untreated cells. Substantial cell attachment and spreading were observed in all materials' surfaces, without significant differences. hDPSCs treated with NeoMTA 2 displayed an upregulation of ALP, Col1A1, RUNX2 (p < 0.001), ON, and DSPP genes (p < 0.05), and showed the highest mineralization potential compared to other groups (p < 0.001). Finally, the more concentrated eluates from these materials, specially NeoMTA Plus and NeoMTA 2, promoted higher ROS production in hDPSCs compared to Bio-C Repair and control cells (p < 0.001), although these ROS levels did not result in increased cell death. CONCLUSIONS: The new tantalum oxide (Ta2O5)-containing material shows an adequate cytocompatibility and the ability to promote biomineralization without using chemical osteogenic inducers, showing great potential as a new material for vital pulp therapy. CLINICAL RELEVANCE: NeoMTA 2 seems to be a promising material for vital pulp therapy. Further studies considering its biocompatibility and biomineralization potential are necessary.

Microstructural composition, ion release, and bioactive potential of new premixed calcium silicate-based endodontic sealers indicated for warm vertical compaction technique.

OBJECTIVE: The aim of this study was to evaluate the microstructural composition, ion release, cytocompatibility, and mineralization potential of Bio-C Sealer ION+ (BCI) and EndoSequence BC Sealer HiFlow (BCHiF), compared with AH Plus (AHP), in contact with human periodontal ligament cells (hPDLCs). MATERIALS AND METHODS: The sealers' ionic composition and release were assessed using energy-dispersive spectroscopy (EDS) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. For the biological assays, hPDLCs were isolated from third molars, and sealer extracts were prepared (undiluted, 1:2, and 1:4 ratios). An MTT assay, wound-healing assay, and cell morphology and adhesion analysis were performed. Activity-related gene expression was determined using RT-qPCR, and mineralization potential was assessed using Alizarin Red staining (ARS). Statistical analyses were performed using one-way ANOVA and Tukey's post hoc test (α < 0.05). RESULTS: The three sealers exhibited variable levels of silicon, calcium, zirconium, and tungsten release and in their composition. Both BCI and BCHiF groups showed positive results in cytocompatibility assays, unlike AHP. The BCHiF group showed an upregulation of CAP (p < 0.01), CEMP1, ALP, and RUNX2 (p < 0.001) compared with the negative control, while the BCI group showed an upregulation of CEMP1 (p < 0.01), CAP, and RUNX2 (p < 0.001). Both groups also exhibited a greater mineralization potential than the negative and positive controls (p < 0.001). CONCLUSIONS: The calcium silicate-based sealers considered in the present in vitro study exhibited a high calcium ion release, adequate cytocompatibility, upregulated osteo/cementogenic gene expression, and increased mineralized nodule formation in contact with hPDLCs. CLINICAL RELEVANCE: From a biological perspective, BCI and BCHiF could be clinically suitable for root canal filling.

Chemical composition and bioactivity potential of the new Endosequence BC Sealer formulation HiFlow.

AIM: To evaluate in a laboratory setting the effects of Endosequence BC Sealer HiFlow (Brasseler USA, Savannah, GA, USA), a novel calcium silicate-based sealer developed for use in warm canal filling techniques, on human periodontal ligament stem cells (hPDLSCs). METHODOLOGY: Eluates of EndoSequence BC Sealer HiFlow (BCHiF) (Brasseler USA), EndoSequence BC Sealer (BCS) (Brasseler USA) and AH Plus (AHP) (Dentsply DeTrey GmbH, Konstanz, Germany) were placed in contact with hPDLSCs. The characterization of the chemical elements of the root canal sealers was assessed using scanning electron microscopy and energy-dispersive X-ray analysis (SEM-EDX). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to determine the ion release of the sealers. MTT assay and wound healing techniques were used to determine cell viability and migration, respectively. Cell morphology and cell attachment were assessed using a direct contact technique of hPDLSCs onto the surface of the sealers and analysed by SEM. The bioactivity potential was carried out with the Alizarin Red and qPCR testing methods. The statistical differences were evaluated using one-way anova and Tukey's test (P < 0.05). RESULTS: ICP-MS and EDX revealed significantly more zirconium in BCHiF than BCS (P < 0.05), whereas BCS had slightly higher levels of Ca2+ than BCHiF (P < 0.05). The cell viability assay revealed no relevant differences between BCS and BCHiF when compared with the control group (P > 0.05). Both BCS and BCHiF had similar rates of cell migration to the control group at 24 and 48 h. Cell morphology and adhesion capacity were also similar for BCS and BCHiF groups, whilst the AHP group was associated with reduced adhesion capacity. The Alizarin Red assay revealed a significant difference between the BCS and the control group (P < 0.001), as well as for the BCHiF group (P < 0.001). Finally, BCS and BCHiF promoted overexpression of osteo/cementogenic genes. CONCLUSIONS: In general, EndoSequence BC Sealer HiFlow possesses suitable biological properties to be safely used as a root canal filling material and promote increased expression of oste/cementogenic genes by hPDLSCs.

Cytocompatibility, bioactivity potential, and ion release of three premixed calcium silicate-based sealers.

OBJECTIVE: Compositional modifications may alter the biological and physicochemical characteristics of calcium silicate-based sealers (CSBS) and, ultimately, their bioactivity. The main objective of this study was to evaluate the biological properties of three CSBS: EndoSequence BC Sealer, Ceraseal, and Endoseal mineral trioxide aggregate. MATERIALS AND METHODS: Human periodontal ligament stem cells (hPDLSCs) were exposed to several eluates of CSBS. The ion release profile and pH were determined, and metabolic activity and cell migration were assessed using the MTT and wound healing assays. hPDLSCs were cultured in direct contact with the surface of each material, and cell morphology and attachment were analyzed by scanning electron microscopy (SEM). Bioactivity potential was assessed by RT-qPCR and mineralization assays. Statistical differences between biomaterials were assessed using one- or two-way ANOVA (α < 0.05). RESULTS: All materials showed an alkaline pH, although Endoseal exhibited a significantly higher pH compared with the other CSBS (p < 0.05). Ceraseal released significantly more Ca2+ (p < 0.05) than EndoSequence BC Sealer and Endoseal. Interestingly, Endoseal induced a significant reduction in cell viability and cell migration compared with the control (p < 0.001). Moreover, SEM showed abundant cells adhering to EndoSequence BC Sealer and Ceraseal surfaces, whereas very few round cells were detected on the surface of Endoseal. Finally, Ceraseal and EndoSequence induced ALP, CAP, and CEMP-1 expression and a significantly higher mineralization capacity than Endoseal (***p < 0.001). CONCLUSIONS: The eluates from EndoSequence BC Sealer and Ceraseal displayed higher cell viability, cell attachment, cell migration rates, and ion release rates than Endoseal. Ceraseal and EndoSequence BC Sealer exhibited significantly more gene expression and mineralization capacity than Endoseal. CLINICAL RELEVANCE: The results obtained in the present work suggest that EndoSequence BC Sealer and Ceraseal possess biological properties that make them suitable materials for root canal treatment.

Comparison of diffusion, cytotoxicity and tissue inflammatory reactions of four commercial bleaching products against human dental pulp stem cells.

Multiple side effects related to bleaching were found to occur in the dental pulp tissue, including decreased cell metabolism and viability. In this work we evaluated the in vitro diffusion capacity, cytotoxicity and biocompatibility of four commercial bleaching products on stem cells from human dental pulp (hDPSCs). Two commercial bleaching gels hydrogen peroxide-based (HP), Norblanc Office 37.5% (Nor-HP) and Opalescence Boost 40% (Opal-HP) were applied for 30 min to enamel/dentine discs. Another two gels from the same manufacturers, 16% carbamide peroxide-based (CP), Norblanc Home (Nor-CP) and Opalescence CP 16% (Opal-CP), were applied for 90 min. The diffusion of HP was analysed by fluorometry. Cytotoxicity was determined using the MTT assays, the determination of apoptosis, immunofluorescence assays and intracellular reactive oxygen species (ROS) level. Tissue inflammatory reactions were evaluated histopathologically in rats. Statistical differences were performed by one-way ANOVA and Bonferroni post-test (α < 0.05). Normon products showed lower cytotoxicity and diffusion capacity than the Ultradent products. A high intracellular ROS level was measured in hDPSCs after exposure to Opal-HP. Finally, a severe necrosis of both coronal and radicular pulp was observed with Opal-HP. Similar concentrations of hydrogen peroxide and carbamide peroxide in a variety of bleaching products exhibited different responses in cells and dental pulp tissue, suggesting that bleaching products contain unknown agents that could influence their toxicity.

Canal shaping with a reciprocating system is easy to learn.

AIM: To assess progressive learning of root canal shaping in order to define the number of simulated canals in resin blocks needed to reach a level of learning beyond which no further improvement in performance is observed. METHODOLOGY: A total of 216 simulated canals in resin blocks were instrumented by 18 operators without experience in Endodontics and by 18 Endodontists. The R25 file of the Reciproc system (VDW, Munich, Germany) was used to prepare the canals. The blocks were photographed before and after instrumentation. An analysis was made of the variations in the dimensions of the canals at 6 locations and of the instrumentation time. A Student's t-test was used to analyse the data (P < 0.05). RESULTS: The group without experience were associated with significant differences in instrumentation time between the first canal and the subsequent canals (P < 0.05) but differences in canal dimensions were not significant (P > 0.05). In the group with experience, the instrumentation time did not differ significantly after the fifth canal, and no significant variations in canal dimensions were observed (P > 0.05). CONCLUSIONS: When conducting studies on root canal shaping or educating students with new instruments, a simulated canal sample size of 6 was appropriate to achieve competence.

Thermographic Analysis of Tooth Vascularization Using Thermal Stimulation.

OBJECTIVE: The current pulp diagnostic techniques based on subjective patient response to electrical or thermal stimuli are unable to assess tooth vascularization, which is a true indicator of pulp vitality. The present study evaluates thermography as a pulp vitality test, assessing tooth recovery following thermal stimulation. METHODS: A model simulating intrapulpal circulation was developed. Superficial thermographic measurements were obtained from teeth with and without elevation of the intracoronal temperature before and after applying thermal stress with cold. The data were analyzed using analysis of variance (ANOVA), and the level of significance was set at P<0.05. RESULTS: The model obtained could help differentiate between teeth with and without simulated pulp circulation. Recovery following application of thermal stress showed significant differences between the two types of teeth. CONCLUSION: Thermography has the potential to be used as a diagnostic tool for the vascularity status of the dental pulp.

Comparing student and staff perceptions of the "Educational Climate" in Spanish Dental Schools using the Dundee Ready Education Environment Measure.

OBJECTIVE: To compare the perceptions of students and teachers of the "Educational Climate" (EC) in Spanish public dental schools. METHODS: A group of 1064 students and 354 teachers from six Spanish public dental schools responded to the DREEM questionnaire. This has 50 items grouped into five subscales: perception of learning (Learning); perception of teachers (Teachers); academic self-perceptions (Academic); perception of the atmosphere in the faculty (Atmosphere); and social self-perceptions (Social). The DREEM scale provides results for each item, each subscale and the overall EC. RESULTS: The EC scores were 123.2 (61.6%) for the students and 134.1 (67.0%) for the teachers (P<.001). The scores of the students and teachers for the subscales were, respectively: 27.9 (58.1%) and 30.2 (63.0 %) for Learning (P<.001); 26.8 (60.9%) and 32.6 (74.1%) for Teachers (P<.001); 20.7 (64.7%) and 20.5 (64.0%) for Academic (P=.333); 29.9 (62.3%) and 33.7 (70.3%) for Atmosphere (P<.001); and 17.9 (64.0%) and 16.9 (60.5%) for Social (P<.001). The students identified six problematic items (12.0 %) compared to only two (4.0 %) highlighted by the teachers. CONCLUSION: The students and teachers considered the EC to be "more positive than negative" in Spanish public dental schools; and the different subscales to be "positive and acceptable." The teachers did, however, evaluate the EC, and specifically the learning-teaching process, more positively than their students, identifying fewer problematic educational aspects. Both groups agreed on the need to: improve support systems for students who suffer from stress and reduce teaching based on "factual learning."

Implementation of augmented reality in operative dentistry learning.

OBJECTIVE: To evaluate the efficacy of augmented reality (AR) in the gaining of knowledge and skills amongst dental students in the design of cavity preparations and analyse their degree of satisfaction. MATERIAL AND METHODS: AR cavity models were prepared for use with computers and mobile devices. Forty-one students were divided into two groups (traditional teaching methods vs AR). Questionnaires were designed to evaluate knowledge and skills, with the administration of a satisfaction questionnaire for those using AR. The degree of compliance with the standards in cavity design was assessed. The Mann-Whitney U-test was used to compare knowledge and skills between the two groups, and the Wilcoxon test was applied to compare intragroup differences. The chi-square test in turn was used to compare the qualitative parameters of the cavity designs between the groups. Statistical significance was considered for P<.05 in all cases. RESULTS: No significant differences were observed in level of knowledge before, immediately after or 6 months after teaching between the two groups (P>.05). Although the results corresponding to most of the studied skills parameters were better in the experimental group, significant differences (P<.05) were only founded for cavity depth and extent for Class I and divergence of the buccal and lingual walls for the Class II. The experience was rated as favourable or very favourable by 100% of the participants. The students showed preference for computers (60%) vs mobile devices (10%). CONCLUSIONS: The AR techniques favoured the gaining of knowledge and skills and were regarded as a useful tool by the students.

Comparative analysis of the biological effects of the endodontic bioactive cements MTA-Angelus, MTA Repair HP and NeoMTA Plus on human dental pulp stem cells.

AIM: To evaluate the biological effects in vitro of MTA-Angelus (MTA-Ang; Angelus, Londrina, PR, Brazil), MTA Repair HP (MTA-HP; Angelus) and NeoMTA Plus (NeoMTA-P; Avalon Biomed Inc, Bradenton, FL, USA) on human dental pulp stem cells (hDPSCs). METHODOLOGY: Cell viability and cell migration assays were performed using eluates of each material. To evaluate cell morphology and cell attachment to the different materials, hDPSCs were directly seeded onto the material surfaces and analysed by immunocytofluorescence and scanning electron microscopy, respectively. The chemical composition of the materials was determined by energy-dispersive X-ray (EDX), and eluates were analysed by inductively coupled plasma-mass spectrometry (ICP-MS). Statistical analysis was performed with the analysis of variance and Bonferroni or Tukey post-test (α < 0.05). RESULTS: Undiluted MTA-Ang, MTA-HP and NeoMTA-P displayed a significant increase in cell viability greater than that obtained using complete medium alone (control) (*P < 0.05; **P < 0.01; ***P < 0.001). Moreover, a cell migration assay revealed cell migration rates after incubation with extracts of MTA-Ang, MTA-HP and NeoMTA-P that were similar to levels obtained in the control group. In addition, stretched cytoskeletal F-actin fibres were detected in the cells treated with the three material extracts. SEM studies revealed a high degree of cell proliferation and attachment on all three materials. EDX analysis demonstrated similar weight percentages of C, O and Ca in all three materials, whilst other elements such as Al, Si and S were also found. CONCLUSIONS: MTA-Ang, MTA-HP and NeoMTA-P were associated with biological effects on hDPSCs in terms of cell proliferation, morphology, migration and attachment.

Cytotoxicity and bioactivity of various pulpotomy materials on stem cells from human exfoliated primary teeth.

AIMS: To investigate the cytotoxicity and bioactivity of several pulpotomy materials: Biodentine (Septodont, Saint-Maur-des-Fosses, France) MTA (Angelus, Londrina, PR, Brazil), Theracal LC (Bisco Inc., Schamburg, IL, USA) and IRM (Dentsply DeTrey GmbH, Konstanz, Germany), after contact with stem cells isolated from human exfoliated primary teeth (SHEDs). METHODOLOGY: SHEDs were cultured in the presence of the eluates of various pulpotomy materials for 24, 48 and 72 h. Cell viability was determined by mitochondrial dehydrogenase enzymatic (MTT) assay. Apoptosis and changes in cell phenotype were evaluated by flow cytometry. Also, an in vitro scratch wound-healing assay was used to determine their effects on cell migration. To assess cell morphology and attachment to the different pulpotomy materials, SHEDs were directly seeded onto the material surfaces and analysed by scanning electron microscopy (SEM). Finally, the deposition of a calcified matrix in presence of these materials was verified by Alizarin Red staining. Statistical analysis was performed with analysis of variance and Bonferroni or Tukey post-test (α = 0.05). RESULTS: Cell viability in the presence of Biodentine eluates was significantly higher to that obtained using complete medium alone (control; P < 0.01) and was also significantly higher than using MTA Angelus from 48 h of incubation (P < 0.01). However, Theracal LC and IRM were associated with low rates of cell viability (P < 0.001). Similar results were obtained in an apoptosis assay. In addition, SHEDs maintained their mesenchymal phenotype in all conditions although their capacity to migrate was higher in the presence of Biodentine. SEM studies revealed a suitable proliferation rate, cell spreading and attachment, especially when using Biodentine and MTA Angelus discs. Finally, Biodentine eluates significantly induced calcified matrix deposition from 7 days of culture (P < 0.01). CONCLUSIONS: Biodentine exhibited better cytocompatibility and bioactivity than MTA Angelus, Theracal LC and IRM.

Biocompatibility of three new calcium silicate-based endodontic sealers on human periodontal ligament stem cells.

AIM: To evaluate the biocompatibility of three calcium silicate-based endodontic sealers, Bioroot BC Sealer (Septodont, Saint-Maur-des-Fosses, France), Endoseal MTA (EndoSeal, Maruchi, Seoul, Korea) and Nano-ceramic Sealer (B&L Biotech, Fairfax, VA, USA) (NCS), on human periodontal ligament stem cells (hPDLSCs). METHODOLOGY: Human periodontal ligament stem cells were cultured in the presence of various endodontic sealer eluates for 24 h. Cell viability was determined using the MTT assay. Cell death and changes in phenotype induced by the set endodontic sealer eluates were evaluated through flow cytometry. Also, an in vitro scratch wound-healing model was used to determine their effects in cell migration. Finally, to assess cell morphology and attachment to the different sealers, hPDLSCs were directly seeded onto the material surfaces and analysed by scanning electron microscopy (SEM). One-way analysis of variance (anova) followed by a Bonferroni post-test was performed (P < 0.05). RESULTS: At 24 h, cell spreading was evident in the presence of Bioroot BC Sealer (BR) and Nano-ceramic Sealer (NCS), but not Endoseal MTA (ES). At 72 h, BR and NCS exhibited high and moderate cell proliferation, respectively, whereas ES revealed low rates of cell proliferation (P < 0.05). Similar results were obtained in a cell death assay. In addition, hPDLSCs maintained their mesenchymal phenotype in all conditions although their capacity to migrate was higher in the presence of BR. Finally, SEM studies revealed a good degree of proliferation, cell spreading and attachment, especially when using BR and NCS discs. CONCLUSIONS: BR and NCS were associated with better cytocompatibility than ES. Further in vitro and in vivo investigations are required to confirm the suitability of these calcium silicate-based endodontic sealers for clinical application.

CPP-ACP and CPP-ACFP versus fluoride varnish in remineralisation of early caries lesions. A prospective study.

AIM: To evaluate the effects of novel casein phosphopeptide (CPP) formulations CPP-amorphous calcium phosphate (CCP- ACP) and CPP-amorphous calcium fluoride phosphate (CPP-ACFP) versus fluoride varnish on the remineralisation of enamel white spot lesions (WSLs) over a 12-week follow-up period. STUDY DESIGN: Double-blind prospective study. Eligibility criteria were patients between 6 and 14 years old and have WSLs on their permanent teeth. We evaluated 786 WSLs. Participants were divided randomly into three groups. Groups A and B were instructed to daily topical application of GC Tooth Mouse (CPP-ACP) or Mi Paste Plus (CPP-ACFP), Group C received a monthly professional application of Duraphat fluoride varnish. WSLs were categorised according to the International Caries Detection and Assessment System (ICDAS II; grades 0-3) and assessed by laser fluorescence (DIAGNOdent) at baseline and at 4, 8 and 12 weeks. Changes in mineralisation before and after treatment were analysed using two-way analysis of variance, with post hoc Bonferroni's non-parametric tests for multiple comparisons. RESULTS: DIAGNOdent values were significantly reduced in Group B at 4 weeks, and in Groups A and C at 8 weeks. Mean values in Group B were lower than in Groups A and C at 4 weeks, and lower than Group C at 8 weeks. CPP-ACFP appeared to have a specific effect on smooth-surface caries, but no significant effect on caries in pits and fissures. CONCLUSION: At 4 weeks, CPP-ACFP is superior to fluoride varnish at remineralising smooth-surface WSLs. CPP-ACP is not superior to fluoride varnish by any of the measures studied.

Association between the number of early carious lesions and diet in children with a high prevalence of caries.

AIM: An investigation was conducted in a population of paediatric patients with a high risk of caries in order to assess the association between caries history (CH) and the number of early carious lesions (ECLs) and the frequency and timing of cariogenic food and beverage intake, sugar-containing medication, the frequency and efficacy of tooth brushing, and the use of topical fluorides. MATERIALS AND METHODS: Study design: descriptive study. One hundred children aged 6-15 years with≥ ECL of a permanent tooth and not enrolled in any dental health educational or preventive programme were selected. For diagnosis it was used an explorer according to the ICDAS II criteria. The participants completed a closed-list questionnaire on the frequency and timing of cariogenic food intake. RESULTS: There was a nonsignificant tendency to present more ECLs and a greater CH among patients who consumed cariogenic foods and beverages. A significant relationship (p<0.05) was observed between cariogenic beverages and the number of ECL or CH. Using the number of ECLs as dependent variable, regular fluoridated rinses (p=0.003), frequent sugar-containing medication (p=0.007), and cariogenic beverage consumption (p=0.024) were identified as explanatory parameters in the linear regression model. STATISTICS: The Student t-test was used to compare ECL and CH with dietetic factors, fluoridated rinses, sugar- containing medicines, and the frequency and efficacy of tooth brushing. Linear regression analysis correlated the number of ECLs to the mentioned explanatory variables. CONCLUSION: The frequent consumption of sugary beverages and medications, and failure to regularly use fluoridated rinses, were positively correlated to an increased number of ECLs in patients with a high prevalence of caries.

Psychometric validation of the Spanish version of the Dundee Ready Education Environment Measure applied to dental students.

AIM: To carry out a psychometric evaluation of the Spanish-language version of the Dundee Ready Education Environment Measure (DREEM) applied to dental students. METHODS: A total of 1,391 students from nine Spanish public schools of dentistry responded to the DREEM questionnaire. To analyse the reliability of the DREEM questionnaire, the internal consistency was assessed and a 'test-retest' carried out. Validity was evaluated through analysis of item response rate, floor and ceiling effects, corrected item-total and item-subscale correlations and factor structure. A confirmatory factor analysis was performed to analyse the structure of the original DREEM scale. RESULTS: Cronbach's alpha coefficient for the 'Educational Climate' (EC) global scale was 0.92. In the subscales, the 'observed' Cronbach's alpha coefficients ranged between 0.57 and 0.79 and were higher than the 'expected' ones; except for the Social subscale. In the DREEM questionnaire, all of the corrected correlation coefficients between the items and the EC global scale, and the items and their corresponding subscales, were >0.2; except for items 50 and 17. All goodness-of-fit indices of confirmatory factor analysis showed acceptable values (close to one or zero, depending on the case), and there was consistency in the results. CONCLUSIONS: The Spanish-language version of the DREEM questionnaire is a reliable and valid instrument for analysing the EC for dental students and its factor structure is supported by the data. Although our findings indicate that the DREEM may be as culturally independent as was originally stated, more research should be directed at verifying the factor structure in various languages and cultural environments.

Analysis of the 'Educational Climate' in Spanish Public Schools of Dentistry using the Dundee Ready Education Environment Measure: a multicenter study.

AIM: To analyse the 'Educational Climate' (EC) of dental students in Spain. METHODS: The study group consisted of 1391 students from nine Spanish Public Schools of Dentistry, who responded to the questionnaire based on 'Dundee Ready Education Environment Measure' (DREEM). This questionnaire has 50 items that are grouped into five domains: Learning, Teachers, Academic, Atmosphere and Social. RESULTS: The global score on the EC was 123.1 (interpretation: 'EC more positive than negative'). The scores obtained in the different domains were: 28.0 in Learning (interpretation: 'a generally positive perception of learning'), 26.8 in Teachers (interpretation: 'teachers are going in the right direction'), 20.8 in Academic (interpretation: 'feeling more on the positive side'), 29.7 in Atmosphere (interpretation: 'a generally positive atmosphere') and 17.7 in Social (interpretation: 'social perception acceptable'). In seven items (14%), an average of <2 was detected, showing that there are some educational problem areas. Regarding the EC in the different Schools of Dentistry, an average of >100 was achieved in all of them, although there were two centres that showed significantly higher values of EC. CONCLUSIONS: Spanish dental students felt that their EC was more positive than negative and considered that the different domains were positive and acceptable. However, they pointed out the existence of several educational problem areas associated with the development of a traditional curriculum. Accordingly, and in parallel with the implementation of an innovative curriculum in all Spanish Dental Schools in the coming years, immediate educational goals must address the problem areas identified, thereby further promoting a more positive perception of EC.

Dietary habits in a child population in relation to caries experience.

Sugar consumption in Spain has remained constant at around 80 g/day since the 1970s. Although intake as sugar has fallen considerably, to around 13.5 g/person/day, the intake in processed foods has risen. Meanwhile, caries prevalence is falling or stabilizing. This situation is common in developed countries, where the impact of diet on caries has altered, probably through greater use of fluoridated products. In the Valencia region, children habitually eat sugary foods and drinks and snacks that contain starches or sugars and starches. The present study analyzed the association between caries experience, quantified as the sum of the dfs and DMFS indices, and the consumption of cariogenic foods in a population of children between the ages of 6 and 10 with low caries prevalence. A self-administered food consumption frequency questionnaire filled in by the parents was used to evaluate how often the foods on the list were consumed by the children, which was then related to their caries experience. Sweet snacks, industrial bread and soft drink consumption showed a positive association with caries while cheese and nuts showed a negative association. Logistic regression suggested that consuming sugary liquids and foods rich in semi-hydrolyzed starch increased the chances of suffering caries by 1.05 and 1.13 respectively.

Sealing capacity of a photochromatic flowable composite as protective base in nonvital dental bleaching.

AIM: To evaluate microleakage of a flowable composite used as a protective isolating base, applied with different adhesive systems. METHODOLOGY: Seventy root-filled teeth were divided into seven groups. A flowable composite base (Tetric Flow Chroma) was used with three adhesive techniques (Syntac, Excite, Excite DCS; in the three cases with and without acid etching) and in a control group without dentine conditioning or adhesive placement. A 30% hydrogen peroxide solution was applied for 24 h in the pulp chambers, followed by the placement of a dye (silver nitrate) for 4 h. Each tooth was sectioned longitudinally, and examined under 4x magnification to assess the tooth/restoration dye leakage following a four-degree scale. Percentage of dye penetration was registered. Statistical analysis was made through the Tukey and Mann-Whitney U-tests. RESULTS: Maximum leakage (100% of specimens) was recorded in the control group without an adhesive system. In the groups subjected to acid etching, the percentage of leakage corresponded to Excite DSC (10%), followed by Syntac (20%) and Excite (30%). In the groups in which only an adhesive system was used, 50% of the teeth demonstrated dye leakage. Statistically significant differences in terms of leakage were observed between the control group and the experimental groups (P < 0.05). There were no significant differences among the experimental groups, but comparing the leakage percentages obtained between the groups in which the teeth were subjected to prior acid etching, and those in which no etching was carried out, observed differences were significant (P = 0.04). CONCLUSIONS: There were no significant differences between the adhesive systems in terms of leakage. Acid etching significantly reduced leakage.