Showing papers in "European Journal of Oral Sciences in 2015"
TL;DR: This study provides a comprehensive overview of the distribution and inter-relations of a set of important salivary biochemical variables in a systemically healthy young adult population, free of apparent caries lesions and periodontal disease, and highlights significant gender differences in Salivary biochemistry.
Abstract: A cross-sectional observational study was conducted to evaluate interindividual biochemical variation in unstimulated whole saliva in a population of 268 systemically healthy young students, 18-30 yr of age, with no apparent caries lesions or periodontal disease. Salivary flow rate, protein content, pH, buffering capacity, mucins MUC5B and MUC7, albumin, secretory IgA, cystatin S, lactoferrin, chitinase, amylase, lysozyme, and proteases were measured using ELISAs and enzymatic activity assays. Significant differences were found between male and female subjects. Salivary pH, buffering capacity, protein content, MUC5B, secretory IgA, and chitinase activity were all lower in female subjects compared with male subjects, whereas MUC7 and lysozyme activity were higher in female subjects. There was no significant difference between sexes in salivary flow rate, albumin, cystatin S, amylase, and protease activity. Principal component analysis (PCA) and spectral clustering (SC) were used to assess intervariable relationships within the data set and to identify subgroups. Spectral clustering identified two clusters of participants, which were subsequently described. This study provides a comprehensive overview of the distribution and inter-relations of a set of important salivary biochemical variables in a systemically healthy young adult population, free of apparent caries lesions and periodontal disease. It highlights significant gender differences in salivary biochemistry. © 2015 Eur J Oral Sci.
76 citations
TL;DR: The presence of an oxygen inhibition layer enhanced the interlayer shear bond strength of all investigated materials, but its absence resulted in cohesive and mixed failures only with the short-fiber-reinforced composite.
Abstract: An oxygen inhibition layer develops on surfaces exposed to air during polymerization of particulate filling composite. This study assessed the thickness of the oxygen inhibition layer of short-fiber-reinforced composite in comparison with conventional particulate filling composites. The effect of an oxygen inhibition layer on the shear bond strength of incrementally placed particulate filling composite layers was also evaluated. Four different restorative composites were selected: everX Posterior (a short-fiber-reinforced composite), Z250, SupremeXT, and Silorane. All composites were evaluated regarding the thickness of the oxygen inhibition layer and for shear bond strength. An equal amount of each composite was polymerized in air between two glass plates and the thickness of the oxygen inhibition layer was measured using a stereomicroscope. Cylindrical-shaped specimens were prepared for measurement of shear bond strength by placing incrementally two layers of the same composite material. Before applying the second composite layer, the first increment's bonding site was treated as follows: grinding with 1,000-grit silicon-carbide (SiC) abrasive paper, or treatment with ethanol or with water-spray. The inhibition depth was lowest (11.6 μm) for water-sprayed Silorane and greatest (22.9 μm) for the water-sprayed short-fiber-reinforced composite. The shear bond strength ranged from 5.8 MPa (ground Silorane) to 36.4 MPa (water-sprayed SupremeXT). The presence of an oxygen inhibition layer enhanced the interlayer shear bond strength of all investigated materials, but its absence resulted in cohesive and mixed failures only with the short-fiber-reinforced composite. Thus, more durable adhesion with short-fiber-reinforced composite is expected.
61 citations
TL;DR: Carious lesions in more advanced stages of progression in anterior and posterior teeth were associated with a negative impact on the quality of life of preschool children.
Abstract: The aim of this cross-sectional study was to evaluate the impact of dental caries on the quality of life of preschool children and their parents/caretakers, with an emphasis on the type of tooth and stage of progression. A randomly selected sample of preschool children, 3-5 yrs of age, underwent an oral examination for the assessment of dental caries using the International Caries Detection and Assessment System II (ICDAS II) criteria. Parents/caretakers answered two questionnaires, one on the oral health-related quality of life (OHRQoL) of the child [the Early Childhood Oral Health Impact Scale (ECOHIS)], and the other on the socio-economic characteristics of the family. Statistical analyses were performed using the chi-square test, Kruskal-Wallis test, Mann-Whitney U-test, and Poisson regression. A total of 451 preschool children participated in the study. The majority of carious lesions exhibited severe decay (60.6%) and were found in both anterior (incisors/canines) and posterior (molars) teeth. The final Poisson model revealed negative impacts on quality of life from more advanced stages of dental caries, both in incisors/canines and molars. Child's age and household income were also associated with impact on quality of life. Carious lesions in more advanced stages of progression in anterior and posterior teeth were associated with a negative impact on the quality of life of preschool children.
59 citations
TL;DR: The LC-MS/MS method without trypsin digestion increased the coverage of identification of the enamel proteome from a few amelogenin peptides to a higher number of peptides from three enamel-specific proteins.
Abstract: Proteins from the extracellular matrix of enamel are highly specific and necessary for proper enamel formation. Most proteins are removed from the matrix by enamel proteases before complete mineralization is achieved; however, some residual protein fragments persist in the mineralized matrix of erupted enamel. So far, only amelogenin peptides obtained by traditional bottom-up proteomics have been recovered and identified in human permanent erupted enamel. In this study, we hypothesize that other enamel-specific proteins are also found in human permanent enamel, by analysing human erupted third molars. Pulverized enamel was used to extract proteins, and the protein extract was subjected directly to liquid-chromatography coupled to tandem mass spectrometry (LC-MS/MS) without a previous trypsin-digestion step. Amelogenin and non-amelogenin proteins (ameloblastin and enamelin) were succesfully identified. The sequences of the naturally occurring peptides of these proteins are reported, finding in particular that most of the peptides from the amelogenin X-isoform come from the tyrosine-rich amelogenin peptide (TRAP) and that some were identified in all specimens. In conclusion, our LC-MS/MS method without trypsin digestion increased the coverage of identification of the enamel proteome from a few amelogenin peptides to a higher number of peptides from three enamel-specific proteins.
43 citations
TL;DR: CAD/CAM-generated crowns, without internal defects, may be applied to molar regions with sufficient fracture resistance, and decreased strength probably resulted from internal voids in the EC&B-layered crowns introduced by the layering process.
Abstract: Harada A, Nakamura K, Kanno T, Inagaki R, Ortengren U, Niwano Y, Sasaki K,€Egusa H. Fracture resistance of computer-aided design/computer-aided manufacturing-generated composite resin-based molar crowns.Eur J Oral Sci 2015; 00: 000–000 © 2015 Eur J Oral SciThe aim of this study was to investigate whether different fabrication processes,such as the computer-aided design/computer-aided manufacturing (CAD/CAM) sys-tem or the manual build-up technique, affect the fracture resistance of compositeresin-based crowns. Lava Ultimate (LU), Estenia CBmanually built-up monolayer composite resin-based crowns (ECB manually built-up layered composite resin-based crowns (ECB and EMP crowns. Each type of crown was cemented to dies and the frac-ture resistance was tested. EC&B-layered crowns showed significantly lower fractureresistance compared with LU and EMP crowns, although there was no significantdifference in flexural strength or fracture toughness between LU and EC&B materi-als. Micro-computed tomography and fractographic analysis showed that decreasedstrength probably resulted from internal voids in the EC&B-layered crowns intro-duced by the layering process. There was no significant difference in fracture resis-tance among LU, EC&B-monolayer, and EMP crowns. Both types of compositeresin-based crowns showed fracture loads of >2000 N, which is higher than themolar bite force. Therefore, CAD/CAM-generated crowns, without internal defects,may be applied to molar regions with sufficient fracture resistance.
38 citations
TL;DR: Based on the results, peri-implant pathology represents a group of multifactorial situations with interaction of biological and biomechanical components in its pathogenesis and it was possible to model the condition and to assess the risk profile of each patient.
Abstract: This study aimed to identify risk factors for the incidence of peri-implant pathology. One-thousand, two-hundred and seventy-fifty patients (255 cases and 1020 controls), rehabilitated with dental implants, were included. Peri-implant pathology was defined as the presence of peri-implant pockets ≥ 5 mm, bleeding on probing, vertical bone loss, and loss of attachment ≥ 2 mm. Cases and controls were matched for age, gender, and duration of follow-up. A logistic regression model was used, with estimation of the OR for each variable and interaction, with a level of significance of 5%. The risk factors for peri-implant pathology were: history of periodontitis (OR = 19), bacterial plaque (OR = 3.6), bleeding (OR = 2.9), bone level on the medium third of the implant (OR = 13.9), lack of prosthetic fit or non-optimal screw joint (OR = 5.9), metal-ceramic restorations (OR = 3.9), and the interaction between bacterial plaque and the proximity of other teeth or implants (PROXI) (OR = 4.3). PROXI (OR = 0.44) exerted a protective effect when independent. Based on the results, peri-implant pathology represents a group of multifactorial situations with interaction of biological and biomechanical components in its pathogenesis. It was possible to model the condition and to assess, with high precision, the risk profile of each patient.
36 citations
TL;DR: It is shown that adults with different lifetime trajectories of dental attendance had different dental statuses, and a consistent pattern of association between long-term dental attendance and caries experience was found in adjusted models.
Abstract: There is inconclusive evidence on the value of regular dental attendance This study explored the relationship between long-term patterns of dental attendance and caries experience We used retrospective data from 3,235 adults, ≥ 16 yrs of age, who participated in the Adult Dental Health Survey in the UK Participants were classified into four groups (always, current, former, and never regular-attenders) based on their responses to three questions on lifetime dental-attendance patterns The association between dental-attendance patterns and caries experience, as measured using the decayed, missing, or filled teeth (DMFT) index, was tested in negative binomial regression models, adjusting for demographic (sex, age, and country of residence) and socio-economic (educational attainment, household income, and social class) factors A consistent pattern of association between long-term dental attendance and caries experience was found in adjusted models Former and never regular-attenders had a significantly higher DMFT score and numbers of decayed and missing teeth, but fewer filled teeth, than always regular-attenders No differences in DMFT or its components were found between current and always regular-attenders The findings of this study show that adults with different lifetime trajectories of dental attendance had different dental statuses
35 citations
TL;DR: The results suggest that sphingolipids may be used to control oral biofilms, especially those loaded with S. mutans, and Atomic force microscopy studies suggested that mechanical stability does not appear to be a factor relevant for anti-fouling activity.
Abstract: This study evaluated the anti-biofilm activity of sphingosine, phytosphingosine (PHS), and sphinganine for: (i) anti-adherence activity on hydroxyapatite (HA) surfaces; and (ii) bactericidal activity on different Streptococcus mutans phenotypes (i.e. planktonic cells and cells from a disrupted biofilm). For this, HA discs treated with sphingolipids were incubated with S. mutans and the number of adherent cells was evaluated by both culture and confocal microscopy. Sphinganine strongly inhibited bacterial adherence by 1000-fold compared with an untreated surface. Phytosphingosine and sphingosine inhibited bacterial adherence by eight- and five-fold, respectively, compared with an untreated surface. On saliva-coated HA, sphinganine and PHS inhibited bacterial adherence by 10-fold. Bactericidal activity of sphingolipids was evaluated by culture. For biofilms, the strongest bactericidal activity was exhibited by sphingosine compared with PHS and sphinganine. At a concentration of 12.5 μg ml−1, PHS and sphingosine were profoundly effective against planktonic and disrupted biofilms; and sphinganine reduced the number of cells in planktonic form by 100-fold and those derived from a disrupted biofilm by 1000-fold. Atomic force microscopy studies suggested that mechanical stability does not appear to be a factor relevant for anti-fouling activity. The results suggest that sphingolipids may be used to control oral biofilms, especially those loaded with S. mutans.
33 citations
TL;DR: Both BAC and MBAC contributed to the preservation of resin-dentin bonds, probably because of their inhibitory properties of endogenous dentin proteinases.
Abstract: Inhibition of endogenous dentin matrix metalloproteinases (MMPs) within incompletely infiltrated hybrid layers can contribute to the preservation of resin-dentin bonds This study evaluated the bond stability of interfaces treated with benzalkonium chloride (BAC) and benzalkonium methacrylate (MBAC), and its inhibitory properties in dentin MMP activity Single-component adhesive ALL-BOND UNIVERSAL, modified with BAC or MBAC in concentrations of 0, 05, 10 and 20% was used for microtensile bond strength (μTBS) evaluation after 24 h, 6 months and 1 yr Human dentin beams were treated with 37% phosphoric acid, dipped either in 05% BAC, 10% BAC or water (control) for 60 s and then incubated in SensoLyte generic MMP substrate to determine MMP activity A significant decrease in μTBS after 6 months and 1 yr was observed for the control group only No significant differences among groups were shown at 24 h After 6 months and 1 yr, the control group demonstrated significantly lower μTBS than all treatment groups Both 05% and 10%, BAC applied for 60 s inhibited total MMP activity by 31% and 54%, respectively Both BAC and MBAC contributed to the preservation of resin-dentin bonds likely due to its inhibitory properties of endogenous dentin proteinases
32 citations
TL;DR: It is demonstrated that BAC contributes to the preservation of resin-dentin bonds for up to 1 yr by reducing collagen degradation.
Abstract: Reducing collagen degradation within hybrid layers may contribute to the preservation of adhesive interfaces. This study evaluated the stability of resin-dentin interfaces treated with benzalkonium chloride (BAC)-modified adhesive blends and assessed collagen degradation in dentin matrices treated with BAC. The etch-and-rinse adhesive, Adper Single Bond Plus, modified with 0.5% and 1.0% BAC, was evaluated for microtensile bond strength (μTBS) and nanoleakage (NL) after 24 h and 1 yr. Thirty completely demineralized dentin beams from human molars were dipped for 60 s in deionized water (DW; control), or in 0.5% or 1.0% BAC, and then incubated in simulated body fluid (SBF). Collagen degradation was assessed by quantification of the dry mass loss and the amount of hydroxyproline (HYP) released from hydrolyzed specimens after 1 or 4 wk. Although all groups demonstrated a significant increase in NL after 1 yr, adhesive modified with 0.5% BAC showed stable bond strength after 1 yr (9% decrease) relative to the control (44% decrease). Significantly less HYP release and dry mass loss were observed for both 0.5% and 1.0% BAC relative to the control. This in vitro study demonstrates that BAC contributes to the preservation of resin-dentin bonds for up to 1 yr by reducing collagen degradation.
32 citations
TL;DR: It was found that toothpastes containing sodium lauryl sulfate and amine fluoride strongly inhibited cell viability with the half-lethal concentration being obtained with conditioned medium prepared with approximately 1% toothpaste (1% TCM).
Abstract: Toothpastes contain three main components: detergents, abrasives, and fluoride. Detergents, particularly sodium lauryl sulfate, have been proposed as components that enable toothpastes to produce cytotoxic effects in vitro. However, not all toothpastes contain sodium lauryl sulfate, and almost no studies have found an association between detergents and the in vitro cytotoxicity of toothpastes. The present study examined the in vitro cytotoxicity of nine commercially available toothpastes containing four different detergents. Toothpastes were diluted in serum-free medium, centrifuged, and filter sterilized. The half-lethal concentration of the toothpaste-conditioned medium (TCM) was calculated based on the formation of formazan by gingival fibroblasts, oral squamous cell carcinoma HSC-2 cells, and L929 cells. Cell proliferation was analyzed, and live-dead staining was performed, after exposure of cells to conditioned medium prepared with 1% toothpaste (1% TCM). It was found that toothpastes containing sodium lauryl sulfate and amine fluoride strongly inhibited cell viability with the half-lethal concentration being obtained with conditioned medium prepared with approximately 1% toothpaste (1% TCM). Toothpastes containing cocamidopropyl betaine and Steareth-20 showed higher half-lethal concentration values, with the half-lethal concentration being obtained with conditioned medium prepared with 10% (10% TCM) and 70% (70% TCM) toothpaste, respectively. Proliferation and live-dead data were consistent with the cell-viability analyses. These results demonstrate that the type of detergent in toothpastes can be associated with changes in in vitro cell toxicity.
TL;DR: The data continue to support that genetic variation may impact enamel development and consequently individual caries susceptibility and these effects may be distinct between primary and permanent dentitions.
Abstract: Clinically, primary and permanent teeth are distinct anatomically and the presentation of caries lesions differs between the two dentitions. Hence, the possibility exists that genetic contributions to tooth formation of the two dentitions are different. The purpose of this study was to test the hypothesis that genetic associations with an artificial caries model will not be the same between primary and permanent dentitions. Enamel samples from primary and permanent teeth were tested for microhardness at baseline, after carious lesion creation, and after fluoride application to verify association with genetic variants of selected genes. Associations were found between genetic variants of ameloblastin, amelogenin, enamelin, tuftelin, tuftelin interactive protein 11, and matrix metallopeptidase 20 and enamel from permanent teeth but not with enamel from primary teeth. In conclusion, our data continue to support that genetic variation may impact enamel development and consequently individual caries susceptibility. These effects may be distinct between primary and permanent dentitions.
TL;DR: The findings of this study show that dental caries treatment has an important impact on OHRQoL of children and the CPQ8-10 was considered an acceptable instrument for longitudinal measurement of changes in OHRZoL.
Abstract: This study aimed to evaluate the impact of dental caries treatment on oral health-related quality of life (OHRQoL) among schoolchildren and the responsiveness of the Child Perceptions Questionnaire (CPQ8-10 ) instrument. Brazilian schoolchildren, 8-10 yr of age, were randomly selected and assigned to two groups--dental caries treatment (DCT) and caries-free (CF)--according to their caries experience [decayed, missing, or filled primary teeth (dmft) and decayed, missing or filled secondary teeth (DMFT) values of ≥ 0]. The CPQ8-10 instrument was administered at baseline and at 4 wk of follow-up (i.e. 4 wk after completion of dental treatment). In the DCT group, increases in CPQ8-10 scores were observed between the baseline and follow-up results. However, longitudinal evaluation of the CF group demonstrated no statistically significant difference in CPQ8-10 scores. Responsiveness of the CPQ8-10 instrument (magnitude of change in CPQ8-10 scores) in the DCT group was greater (effect size >0.7) than in the CF group. The findings of this study show that dental caries treatment has an important impact on OHRQoL of children. The CPQ8-10 was considered an acceptable instrument for longitudinal measurement of changes in OHRQoL.
TL;DR: The OMES-expanded is valid and reliable for evaluating orofacial myofunctional disorders of patients with obstructive sleep apnea, with adequate psychometric properties.
Abstract: There is no standardized protocol for the clinical evaluation of orofacial components and functions in patients with obstructive sleep apnea. The aim of this study was to examine the validity, reliability, and psychometric properties of the Expanded Protocol of Orofacial Myofunctional Evaluation with Scores (OMES-expanded) in subjects with obstructive sleep apnea. Patients with obstructive sleep apnea and control subjects were evaluated, and the validity of OMES-expanded was tested by construct validity (i.e. the ability to discriminate orofacial status between apneic and control subjects) and criterion validity (i.e. correlation between OMES-expanded and a reference instrument). Construct validity was adequate; the apneic group showed significantly worse orofacial status than did control subjects. Criterion validity of OMES-expanded was good, as was its reliability. The OMES-expanded is valid and reliable for evaluating orofacial myofunctional disorders of patients with obstructive sleep apnea, with adequate psychometric properties. It may be useful to plan a therapeutic strategy and to determine whether the effects of therapy are related to improved muscle and orofacial functions.
TL;DR: A Chinese patient with the typical traits of TDO - kinky hair, enamel hypoplasia, skull and jaw bones thickening, and sclerosis is described, and genetic analysis revealed a novel de novo missense mutation c.533A>G (p.Q178R) in the conserved homeodomain of the DLX3 gene.
Abstract: Tricho-dento-osseous (TDO) syndrome, an autosomal-dominant disorder, affects the morphological appearance of the tooth enamel, hair, and bone. Previous studies have confirmed that mutations in the DLX3 gene are responsible for TDO. In this study, we describe a Chinese patient with the typical traits of TDO - kinky hair, enamel hypoplasia, skull and jaw bones thickening, and sclerosis. Unfortunately, as a result of excessive attrition, we were unable to assess taurodontism. Examination of the tooth ground section showed a thin layer of enamel with no rods on the patient's tooth and abnormalities in Tomes' granular layer and the dentinal tubules. Scanning electron microscopy and energy-dispersive X-ray spectroscopy of the tooth enamel showed significant differences between the patient and the control individuals. A hair sample from the patient observed under a laser-scanning microscope showed longitudinal grooves in the hair shaft. Dual-energy X-ray absorptiometry measurement showed that the bone mineral density values of the patient's bones was much higher than normal. Finally, genetic analysis revealed a novel de novo missense mutation c.533A>G (p.Q178R) in the conserved homeodomain of the DLX3 gene. This DLX3 mutation is the sixth causative mutation for TDO to be identified so far.
TL;DR: It is found that inactivating Fam20B in the dental epithelium leads to supernumerary maxillary and mandibular incisors and opens a new window for understanding the regulatory mechanism of PG-mediated signaling cascades during tooth formation.
Abstract: Tooth formation is tightly regulated by epithelial-mesenchymal interactions via hierarchic cascades of signaling molecules. The glycosaminoglycan (GAG) chains covalently attached to the core protein of proteoglycans (PGs) provide docking sites for signaling molecules and their receptors during the morphogenesis of tissues and organs. Although PGs are believed to play important roles in tooth formation, little is known about their exact functions in this developmental process and the relevant molecular basis. Family with sequence similarity member 20-B (FAM20B) is a newly identified kinase that phosphorylates the xylose in the common linkage region connecting the GAG with the protein core of PGs. The phosphorylation of xylose is essential for elongation of the common linkage region and the subsequent GAG assembly. In this study, we generated a Fam20B-floxed allele in mice and found that inactivating Fam20B in the dental epithelium leads to supernumerary maxillary and mandibular incisors. This finding highlights the pivotal role of PGs in tooth morphogenesis and opens a new window for understanding the regulatory mechanism of PG-mediated signaling cascades during tooth formation.
TL;DR: Using a fluoride rinse helps to maintain better oral health during fixed appliance treatment, resulting in fewer demineralizations, in conclusion.
Abstract: Demineralizations around orthodontic brackets are a main disadvantage of orthodontic treatment. Several methods have been advocated to prevent their development, such as fluoride rinses or varnishes. In this randomized clinical trial, a fluoride rinse (a combination of sodium fluoride and amine fluoride) was compared with a placebo rinse, to be used every evening after toothbrushing. A total of 81 participants (mean age: 13.3 yr) completed the study (mean treatment period: 24.5 months). Demineralizations, measured using quantitative light-induced fluorescence and the decayed, missing, and filled surfaces (DMFS) index, were assessed before treatment (baseline) and around 6 wk after debonding (post treatment). Bleeding scores were measured at baseline, and during and post treatment. The incidence rate ratio for demineralizations was 2.6 (95% CI: 1.1-6.3) in the placebo group vs. the fluoride group. In the fluoride group, 31% of participants developed at least one demineralization, compared with 47% in the placebo group. Relative to baseline, gingival bleeding increased significantly in the placebo group 1 yr after the start of treatment and onwards. For the fluoride group, bleeding scores during treatment were not different from those at baseline. In conclusion, using a fluoride rinse helps to maintain better oral health during fixed appliance treatment, resulting in fewer demineralizations.
TL;DR: Results indicate that HEMA-induced cell damage is not caused exclusively by these mechanisms, and Mechanisms other than glutathione depletion and ROS formation seem to be of importance for the toxic effect of HEMA on lung epithelial cells.
Abstract: 2-Hydroxyethyl methacrylate (HEMA) is a methacrylate monomer used in polymer-based dental-restorative materials. In this study, the viability of human lung epithelial cells, BEAS-2B, was investigated after exposure to this monomer. Exposure to HEMA reduced the viability of the BEAS-2B cells as a result of increased apoptosis, interruption of the cell cycle, and decreased cell proliferation. Depletion of cellular glutathione and increased levels of reactive oxygen species (ROS) were seen after exposure of BEAS-2B cells to HEMA. The glutathione synthase inhibitor, L-buthioninesulfoximine (BSO), was used to study whether the reduced viability was caused by glutathione depletion and increased levels of ROS. Similarly to incubation with HEMA, incubation with BSO resulted in glutathione depletion and increased ROS levels, without increasing cell death or inhibiting cell growth. The results indicate that HEMA-induced cell damage is not caused exclusively by these mechanisms. Mechanisms other than glutathione depletion and ROS formation seem to be of importance for the toxic effect of HEMA on lung epithelial cells.
TL;DR: Histological examination showed that all experimental groups exhibited agglomerates, in the gingiva, of titanium particles of micrometer size range, with no associated inflammatory response, which could be considered a tissue indicator of tribocorrosion processes of titanium bioimplants.
Abstract: Fil: Guglielmotti, Maria Beatriz. Universidad de Buenos Aires. Facultad de Odontologia; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina
TL;DR: The enamel demineralization-prevention ability and shear bond strength (SBS) properties of 4-methacryloxyethyl trimellitic anhydride/methyl methacrylate-tri-n-butyl borane (4-META/MMA-TBB)-based resin containing various amounts (0-50%) of bioactive glass (BG) were investigated, suggesting that this material has the ability to prevent enamel Demin
Abstract: We investigated the enamel demineralization-prevention ability and shear bond strength (SBS) properties of 4-methacryloxyethyl trimellitic anhydride/methyl methacrylate-tri-n-butyl borane (4-META/MMA-TBB)-based resin containing various amounts (0-50%) of bioactive glass (BG). Disk-shaped specimens were immersed in distilled water and ions released were analysed by inductively coupled plasma atomic-emission spectroscopy. Samples were also immersed in lactic acid solution (pH 4.6) to estimate acid-neutralizing ability. Brackets were bonded to human premolars with BG-containing resins and the bonded teeth were alternately immersed in demineralizing (pH 4.55) and remineralizing (pH 6.8) solutions for 14 d. The enamel hardness was determined by nanoindentation testing at twenty equidistant distances from the external surface. The SBS for each sample was examined. The amounts of ions released [calcium (Ca), sodium (Na), silicon (Si), and boron (B)] and the acid-neutralizing ability increased with increasing BG content. After alternating immersion, the specimens bonded with the BG-containing resin with high BG content were harder than those in the other groups in some locations 1-18.5 μm from the enamel surface. Bioactive glass-containing (10-40%) resin had bond strength equivalent to the control specimen. Thus, the SBS obtained for BG-containing resin (6.5-9.2 MPa) was clinically acceptable, suggesting that this material has the ability to prevent enamel demineralization.
TL;DR: The data support the view that apical CFTR in maturation ameloblasts tranduces chloride into developing enamel as part of the machinery to buffer protons released during mineral accretion.
Abstract: Formation of crystals in the enamel space releases protons that need to be buffered to sustain mineral accretion. We hypothesized that apical cystic fibrosis transmembrane conductance regulator (CFTR) in maturation ameloblasts transduces chloride into forming enamel as a critical step to secrete bicarbonates. We tested this by determining the calcium, chloride, and fluoride levels in developing enamel of Cftr-null mice by quantitative electron probe microanalysis. Maturation-stage enamel from Cftr-null mice contained less chloride and calcium than did wild-type enamel, was more acidic when stained with pH dyes ex vivo, and formed no fluorescent modulation bands after in vivo injection of the mice with calcein. To acidify the enamel further we exposed Cftr-null mice to fluoride in drinking water to stimulate proton release during formation of hypermineralized lines. In Cftr-deficient mice, fluoride further lowered enamel calcium without further reducing chloride levels. The data support the view that apical CFTR in maturation ameloblasts tranduces chloride into developing enamel as part of the machinery to buffer protons released during mineral accretion.
TL;DR: The results reveal that TRPV1 expression is modulated by experimental tooth movement and is involved in tooth-movement pain.
Abstract: To investigate whether transient receptor potential vanilloid type 1 (TRPV1) is involved in pain induced by experimental tooth movement, experiments were performed in male Sprague-Dawley rats weighing 200–250 g. Directed face-grooming behavior was used to evaluate nocifensive behavior in rats during experimental tooth movement. The distribution of TRPV1 in the trigeminal ganglion (TG) was evaluated by immunohistochemistry, and its expression was detected by western blotting at several time points following the application of various magnitudes of force during tooth movement. Immunohistochemical analysis revealed that TRPV1 was expressed in TG, and its expression was increased after experimental tooth movement. Western blot results also showed that experimental tooth movement led to a statistically significant increase in expression of TRPV1 protein in TG. Meanwhile, the time spent on directed face-grooming peaked on day 1 and thereafter showed a gradual decrease. In addition, both the change in TRPV1 expression in the TG and directed face-grooming behavior were modulated in a force-dependent manner and in concert with initial orthodontic pain responses. Our results reveal that TRPV1 expression is modulated by experimental tooth movement and is involved in tooth-movement pain.
TL;DR: The latest information on the standards of animal research in dentistry is presented, more precisely in the field of implant dentistry, where issues on precision and risk of bias are discussed, and strategies to reduce risk of biases are reported.
Abstract: Animal experiments are critical for the development of new human therapeutics because they provide mechanistic information, as well as important information on efficacy and safety. Some evidence suggests that authors of animal research in dentistry do not observe important methodological issues when planning animal experiments, for example sample-size calculation. Low-quality animal research directly interferes with development of the research process in which multiple levels of research are interconnected. For example, high-quality animal experiments generate sound information for the further planning and development of randomized controlled trials in humans. These randomized controlled trials are the main source for the development of systematic reviews and meta-analyses, which will generate the best evidence for the development of clinical guidelines. Therefore, adequate planning of animal research is a sine qua non condition for increasing efficacy and efficiency in research. Ethical concerns arise when animal research is not performed with high standards. This Focus article presents the latest information on the standards of animal research in dentistry, more precisely in the field of implant dentistry. Issues on precision and risk of bias are discussed, and strategies to reduce risk of bias in animal research are reported.
TL;DR: This is the first report implicating coding variants in the WNT10A gene in the aetiology of MLIA, and will require further confirmation using larger-scale studies.
Abstract: Congenital maxillary lateral incisor agenesis (MLIA) is one of the most common subtypes of dental agenesis. Because little is known with regard to the aetiology of this anomaly, the aim of the study was to determine the contribution of nucleotide variants in wingless-type MMTV integration site family, member 10A (WNT10A), msh homeobox 1 (MSX1), and paired box 9 (PAX9) to the risk of MLIA in a Polish population. Coding regions of the selected genes were analysed by direct sequencing in a group of 20 individuals with unilateral and bilateral MLIA, associated or not with other dental anomalies. The frequencies of the identified nucleotide variants were assessed in an additional cohort of patients with isolated dental agenesis (n = 147) and in 178 controls. Mutation screening showed four non-synonymous substitutions located in the highly conserved coding sequence of WNT10A in five (25%) of the 20 patients. Analysis of genotyping results revealed that three of these variants – p.Arg113Cys, p.Phe228Ile, and the newly identified p.Arg171Leu – may represent aetiological mutations underlying MLIA with associated dental anomalies. No mutations that were potentially aetiologic were identified in MSX1 and PAX9. In conclusion, this is the first report implicating coding variants in the WNT10A gene in the aetiology of MLIA. These results will require further confirmation using larger-scale studies.
TL;DR: Social-condition differentials in negative oral attitudes and tooth loss seem to remain stable or to narrow weakly after the usual age of retirement, and the social mobility and accumulation life-course models were supported.
Abstract: This study examined the relationship of trajectories in social condition with oral attitudes and major tooth loss, using the social mobility and accumulation life-course models in a cohort. Whether social-condition inequalities remained stable or changed from 65 yr of age to 70 yr of age was investigated. In 1992, 6,346 inhabitants born in 1942 and residing in two Swedish counties agreed to participate in a prospective survey. Of the participants in 1992, 3,585 (47.6% men) completed questionnaires in 1997, 2002, 2007, and 2012. In line with the social-mobility model, the prevalence of negative oral attitudes and major tooth loss in participants at 65 and 70 yr of age showed a consistent gradient according to social-condition trajectory, whereby it was lowest among those who were persistently high and highest among those who were persistently low, with the upwardly and downwardly mobile categories being intermediate. A linear graded association between the number of periods with disadvantaged social condition and oral health supported the accumulation model. Both the social mobility and accumulation life-course models were supported. Social-condition differentials in negative oral attitudes and tooth loss seem to remain stable or to narrow weakly after the usual age of retirement.
TL;DR: The study shows promising findings for the reliability and validity of the Swedish translation of the IDAF-4C(+) , as a useful measure of dental anxiety in research and clinical practice.
Abstract: Dental anxiety (DA) is a common condition, with significant medical, psychological, and social consequences. High-quality psychometric tools for the assessment of dental anxiety are necessary for clinical and research purposes. The aim of this study was to adapt the Index of Dental Anxiety and Fear (IDAF-4C(+) ) to the Swedish language and to explore the psychometric properties of the translated version. The study included a clinical sample (n = 414; 17-91 yr of age) and a non-clinical sample (n = 51; 19-47 yr of age). The scales used were the IDAF-4C(+) , the Single-Question Assessment of Dental Anxiety (SQDA), the Dental Fear Survey (DFS), and the Internal Health Locus of Control (IHLOC). The Swedish IDAF anxiety module showed a clear, one-dimensional structure, good internal consistency (Cronbach's alpha = 0.95), and adequate validity, as evidenced by strong correlations with the other DA measures (SQDA and DFS) and weak correlations with the IHLOC. In addition, the IDAF phobia module and the IDAF stimulus module were strongly correlated with the other DA measures. To conclude, the study shows promising findings for the reliability and validity of the Swedish translation of the IDAF-4C(+) , as a useful measure of dental anxiety in research and clinical practice.
TL;DR: The bond strength between a ceramic and cast and milled CoCr alloys was evaluated using a three-point bending test according to ISO9693 and resulted in the highest bond strength.
Abstract: There is a dearth of dental scientific literature on the effect of different oxidation heat treatments (OHTs) (as surface pretreatments) on the bonding performance of cast and milled cobalt-chromium (CoCr) alloys. The objective of this study was to evaluate the effect of different OHTs on the bond strength between a ceramic and cast and milled CoCr alloys. Cobalt-chromium metallic specimens were prepared using either a cast or a milled method. Specimens were subjected to four different OHT methods: without OHT; OHT under normal atmospheric pressure; OHT under vacuum; and OHT under vacuum followed by sandblasting. The metal-ceramic bond strength was evaluated using a three-point bending test according to ISO9693. Scanning electron microscopy and energy-dispersive spectroscopy were used to study the specimens' microstructure and elemental composition. The bond strength was not affected by the CoCr manufacturing method. Oxidation heat treatment performed under normal atmospheric pressure resulted in the highest bond strength. The concentration of oxygen on the alloy surfaces varied with the different pretreatment methods in the following order: OHT under normal atmospheric pressure > OHT under vacuum > without OHT ≈ OHT under vacuum followed by sandblasting.
TL;DR: The proposed changes, and their rationales, are discussed, and it is concluded that the periodontal classification carousel will continue to spin until it is realized that the only way forward is a profound reconsideration of what the authors hope to achieve with classifications.
Abstract: An American Academy of Periodontology Task Force has recently published a report on the Update to the 1999 Classification of Periodontal Diseases and Conditions, which is a focused update outlining changes to be included in a comprehensive update planned for 2017. We discuss the proposed changes, and their rationales, and conclude that the periodontal classification carousel will continue to spin until it is realized that the only way forward is a profound reconsideration of what we hope to achieve with classifications.
TL;DR: To compare the cutting efficiency of diamond burs, operated using an electric high-speed dental handpiece, on zirconia (Zir) with those on lithium disilicate glass-ceramic (LD) and leucite glass- Aceramic (L), evaluation of the cutting Efficiency showed significantly higher cutting efficiency on Zir than the C grains.
Abstract: Zirconia-based dental restorations are becoming used more commonly. However, limited attention has been given to the difficulties experienced, concerning cutting, in removing the restorations when needed. The aim of the present study was to compare the cutting efficiency of diamond burs, operated using an electric high-speed dental handpiece, on zirconia (Zir) with those on lithium disilicate glass-ceramic (LD) and leucite glass-ceramic (L). In addition, evaluation of the cutting efficiency of diamond burs on Zir of different thicknesses was performed. Specimens of Zir were prepared with thicknesses of 0.5, 1.0, 2.0, and 4.0 mm, and specimens of LD and L were prepared with a thickness of 1.0 mm. Cutting tests were performed using diamond burs with super coarse (SC) and coarse (C) grains. The handpiece was operated at 150,000 rpm with a cutting force of 0.9 N. The results demonstrated that cutting of Zir took about 1.5- and 7-fold longer than cutting of LD and L, respectively. The SC grains showed significantly higher cutting efficiency on Zir than the C grains. However, when the thickness of Zir increased, the cutting depth was significantly decreased. As it is suggested that cutting of zirconia is time consuming, this should be taken into consideration in advance when working with zirconia restorations.
TL;DR: It is suggested that knockdown of FAK can decrease the production of TNF-α-induced IL-6, IL-8, and MMP-2 in HPDLFs, which may help in understanding the mechanisms that control expression of inflammatory cytokines in the pathogenesis of periodontitis.
Abstract: Since focal adhesion kinase (FAK) was proposed as a mediator of the inflammatory response, we have investigated the role of this molecule in the release of inflammatory cytokines by cultured human periodontal ligament fibroblasts (HPDLFs), cells that are thought to be important in the patient's response to periodontal infection. Human periodontal ligament fibroblasts were stimulated by tumor necrosis factor alpha (TNF-α) and its effects on interleukin (IL)-6 and IL-8 release were measured by ELISA. Expression of matrix metalloproteinase 2 (MMP-2) protein was analysed by western blotting. The levels of IL6, IL8, and MMP2 mRNA were evaluated by real-time PCR. Tumor necrosis factor alpha dose-dependently induced the phosphorylation of FAK, whereas small interfering FAK (siFAK) inhibited TNF-α-induced FAK phosphorylation. Tumor necrosis factor alpha also stimulated the production of IL-6, IL-8, and MMP-2 in a dose-dependent manner. Knockdown of FAK significantly suppressed TNF-α-induced expression of IL6 and IL8 mRNA and release of IL-6 and IL-8 protein in HPDLFs. Similarly, MMP-2 down-regulation was significantly prevented by siFAK. Our results strongly suggest that knockdown of FAK can decrease the production of TNF-α-induced IL-6, IL-8, and MMP-2 in HPDLFs. These effects may help in understanding the mechanisms that control expression of inflammatory cytokines in the pathogenesis of periodontitis.