Autoimmune amelogenesis imperfecta in patients with APS-1 and coeliac disease.

Ameloblasts are specialized epithelial cells in the jaw that have an indispensable role in tooth enamel formation-amelogenesis1. Amelogenesis depends on multiple ameloblast-derived proteins that function as a scaffold for hydroxyapatite crystals. The loss of function of ameloblast-derived proteins results in a group of rare congenital disorders called amelogenesis imperfecta2. Defects in enamel formation are also found in patients with autoimmune polyglandular syndrome type-1 (APS-1), caused by AIRE deficiency3,4, and in patients diagnosed with coeliac disease5-7. However, the underlying mechanisms remain unclear. Here we show that the vast majority of patients with APS-1 and coeliac disease develop autoantibodies (mostly of the IgA isotype) against ameloblast-specific proteins, the expression of which is induced by AIRE in the thymus. This in turn results in a breakdown of central tolerance, and subsequent generation of corresponding autoantibodies that interfere with enamel formation. However, in coeliac disease, the generation of such autoantibodies seems to be driven by a breakdown of peripheral tolerance to intestinal antigens that are also expressed in enamel tissue. Both conditions are examples of a previously unidentified type of IgA-dependent autoimmune disorder that we collectively name autoimmune amelogenesis imperfecta.

Predicting intention of Norwegian dental health-care workers to use nanomaterials: An application of the augmented theory of planned behavior.

Due to the rapid development of nanotechnology and its integration into dentistry, there is a need for information on the factors influencing the decision of dental health-care workers to use nanomaterials. Based on a national survey among Norwegian dentists and dental hygienists, this study applied the theory of planned behavior (TPB), augmented with past behavior and perceived risk, to predict the intention to use dental nanomaterials in the future and to assess whether an augmented TPB model operates equivalently across professional groups. Structural equation modelling was used to assess whether the hypothesized model fits the data. Of 1792 eligible participants, 851 responded to an electronic survey. Attitudes and perceived behavioral control had the strongest effect on intention, followed by past behavior and subjective norms. Risk perceptions had an indirect effect on intention. Multigroup comparison confirmed invariance of the model across professional groups. This study supports the validity of the augmented TPB model to explain the intention of Norwegian dentists and dental hygienists to use nanomaterials. The strongest influence on intention is given by the attitudes toward nanomaterials and perceived confidence in their use. The findings of the study have implications for management of the use of nanomaterials in dentistry by policy makers.

Use of nanomaterials in dentistry: covariates of risk and benefit perceptions among dentists and dental hygienists in Norway.

Objective: Focusing dentists and dental hygienists employed in the Public Dental Health Services (PDHSs) in Norway, this study set out to assess whether socio-demographic factors, familiarity with nanotechnology and social trust are associated with dental health care workers' perceived risks and benefits of use of nanomaterials in dentistry and whether those associations varied according to professional status. It was hypothesized that increased knowledge, trust in stakeholders and familiarity with nanomaterials would decrease the risk and increase benefit perceptions among dental health care workers.Methods: Electronic questionnaires were administered to a census of 1792 dentists and dental hygienists.Results: About 64% and 69% of respondents perceived respectively, risk and benefits associated with use of nanomaterials. Multiple variable logistic regression revealed that dentists were more likely than hygienists to perceive risks (OR = 1.9, 95% CI 1.1-3.3) and benefits (OR = 3.6, 95% CI 2.1-6.2). Having experience with dental nanomaterials (OR = 2.2, 95% CI 1.3-3.7) and feeling safe (OR = 6.6, 95% CI 3.1-14.2) increased perceived benefits. Having moderate or much correct knowledge about nanotechnology (OR = 2.3, 95% CI 1.5-3.5) increased the likelihood of perceived risk.Conclusions: Policy makers should consider the factors that influence dental health care workers' risk and benefit perceptions associated with the use of nanomaterials in dentistry.

Knowledge about nanotechnology and intention to use nanomaterials: A comparative study among dental students in Norway and Romania.

BACKGROUND: The introduction of innovative nanotechnologies in medicine and dentistry may initiate a need for curriculum revision at the universities. The aim of this study was to assess dental students' knowledge and attitudes related to nanotechnology. Covariates of students' intention to use nanomaterials in their future dental practice were evaluated using the theory of planned behaviour (TPB). METHODS: Dental students at Norwegian and Romanian Universities were invited to participate. A self-administered structured questionnaire including socio-demographics and Ajzen's TPB components was used. FINDINGS: A total of 212 out of 732 dental students participated in the survey: 52 Norwegian and 160 Romanian. Most students reported to have little knowledge about nanotechnology (Norwegians = 44.2% vs Romanians = 46.9%, P < .05). More than 90% of the students in both countries reported that they wanted to get more information about nanotechnology. Mean knowledge score was similar for Norwegian and Romanian students (4.4 ± 1.7 vs 4.2 ± 1.4, P > .05). Romanian students had more positive attitude, stronger subjective norms and stronger perceived behavioural control towards nanotechnology compared to their Norwegian counterparts. Intention to use nanomaterials in the total sample was most strongly influenced by attitude towards the use of dental nanomaterials (beta = 0.42, P < .001). CONCLUSION: Dental students in Norway and Romania demonstrated limited knowledge about nanotechnology. Intention to use nanomaterials was primarily influenced by attitudes. A clear desire for more information about the application of nanotechnology in dentistry was expressed by the respondents indicating a need for curriculum modification.

Nano-TiO2 penetration of oral mucosa: in vitro analysis using 3D organotypic human buccal mucosa models.

BACKGROUND: Oral cavity is a doorway for a variety of products containing titanium dioxide (TiO2 ) nanoparticles (NPs) (nano-TiO2 ) such as food additives, oral healthcare products and dental materials. Their potential to penetrate and affect normal human oral mucosa is not yet determined. OBJECTIVES: To evaluate the ability of nano-TiO2 to penetrate the in vitro reconstructed normal human buccal mucosa (RNHBM). METHODS: RNHBM was generated from primary normal human oral keratinocytes and fibroblasts isolated from buccal oral mucosa of healthy patients (n = 6). The reconstructed tissues were exposed after 10 days to clinically relevant concentrations of spherical or spindle rutile nano-TiO2 in suspension for short (20 min) and longer time (24 h). Ultrahigh-resolution imaging (URI) microscopy (CytoViva™ , Auburn, AL, USA) was used to assess the depth of penetration into reconstructed tissues. RESULTS: Ultrahigh-resolution imaging microscopy demonstrated the presence of nano-TiO2 mostly in the epithelium of RNHBM at both 20 min and 24-h exposure, and this was shape and doze dependent at 24 h of exposure. The depth of penetration diminished in time at higher concentrations. The exposed epithelium showed increased desquamation but preserved thickness. CONCLUSION: Nano-TiO2 is able to penetrate RNHBM and to activate its barrier function in a doze- and time-dependent manner.

A comparison of two clinical methods for measuring saliva in patients with Sjögren's syndrome.

OBJECTIVE: The aim of the present study was to evaluate two different ways of measuring unstimulated and stimulated whole salivary output in the dental clinic, namely by volume (mL/min) and by weight (g/min). MATERIALS AND METHODS: Thirty-one patients diagnosed with Secondary Sjögren's syndrome (SSS) participated in the study. RESULTS: The results showed a large discrepancy between the measurements performed by volume and by weight (p < 0.001) and additionally when taking into account density calculation, especially in individuals with low salivary secretion rate. CONCLUSION: It is suggested that weight measurement of saliva should be more routinely implemented, especially in patients with reduced salivary secretion.

Acute Dental Pain and Salivary Biomarkers for Stress and Inflammation in Patients with Pulpal or Periapical Inflammation.

AIMS: To investigate whether acute dental pain due to pulpal or periapical inflammation is associated with increased expression of cortisol and inflammatory markers and mediators in the saliva, as well as changes in salivary flow rate. METHODS: Patients experiencing pain (n = 42) were recruited when seeking emergency dental treatment. A 0 to 10 numeric rating scale (NRS) was used as a measure of the severity of pain, and the number of days with pain sensation was also recorded. Unstimulated saliva was collected for 3 minutes (salivary flow measured in mL/minute) and stored at -80°C. Saliva was analyzed for the biomarkers cortisol, C-reactive protein (CRP), and cytokines interleukin-1ß (IL-1ß) and interleukin-6. In addition, the participants completed a simple questionnaire about stress-inducing factors such as insomnia, dental anxiety, or home/workplace stress. Patients received a dental examination and diagnosis (eg, symptomatic pulpitis/apical periodontitis or acute apical abscess), which was confirmed during dental treatment. The control group (n = 39) consisted of participants without any pain and no known medical or dental problems. RESULTS: Patients experiencing acute pain due to pulpal or periapical inflammation had a mean NRS score of 7.0 ± 2.59. The mean duration of pain was 6.5 ± 7.9 days. There was no significant difference in pain level between male and female subjects, tooth type affected, or diagnosis. Higher levels of cortisol, IL-1ß, and IL-6 and increased salivary flow were detected in patients with pain when compared to controls (P < .05). CRP was higher in patients with acute pain compared to control participants without pain, but this difference was not statistically significant. Stress at home or the workplace was reported by 79% of patients experiencing pain and by 28% of control participants. CONCLUSION: Acute dental pain due to pulpal or periapical inflammation was associated with an increase in salivary cortisol, IL-1ß, and IL-6 levels and in salivary flow rate. Stress arising from home or the workplace may aggravate a symptom-free pulpal or periapical inflammation to an acute phase. Inflammation in the pulp and periapical region can have effects in regions remote from the disease site.

Oral microbiota in autoimmune polyendocrine syndrome type 1.

Background: Autoimmune polyendocrine syndrome type-1 (APS-1) is a rare, childhood onset disease caused by mutations in the Autoimmune Regulator gene. The phenotypic expression is highly variable and includes disease manifestations in the oral cavity, including mucocutaneous candidiasis. Increasing evidence suggests a potential role of the skin, oral and gut microbiotas in the pathogenesis of autoimmunity. To date, no information exists regarding the oral microbiota in APS-1. Objective: To assess the bacterial microbiota of whole saliva in APS-1 patients by using high throughput sequencing. Design: Whole unstimulated saliva was collected from 10 APS-1 patients and 17 healthy controls and examined by high throughput sequencing of the hypervariable region V1-V2 of 16S rRNA using the 454 GS Junior system. Metastats (http://cbcb.umd.edu/software/metastats) was used to analyse the pyrosequencing reads. Results: A reduction in the total number of bacterial genera and species was detected in APS-1 compared to healthy controls. The proportion of the major phyla Firmicutes was higher (60% vs 41%, p = 0.002) and Bacteroidetes lower (15% vs 28%, p = 0.007) in APS-1 compared to healthy controls. On the genus level, Streptococcus and Gemella were prevalent in APS-1. Conclusion: Our findings indicate a significantly altered oral microbiota in APS-1.

Impaired salivary gland activity in patients with autoimmune polyendocrine syndrome type I.

Autoimmune polyendocrine syndrome type I (APS-I) is a severe disease caused by mutations in the autoimmune regulator (AIRE) gene. We hypothesized that salivary gland dysfunction could be a possible unexplored component of these patients and here aimed to investigate salivary and lachrymal symptoms in the Norwegian cohort of APS-I patients (N = 41) and the aetiology behind it. Sicca symptoms and possible corresponding underlying factors were assessed by subjective reports combined with objective measures of saliva and tear flow, serological testing, immune fluorescence microscopy, ultrasonography and searching for putative autoantibodies in the salivary glands. In addition, defensin and anti-defensin levels were analysed in patients and compared with healthy controls. Our results indicate mild salivary and/or lachrymal gland dysfunction manifesting in low saliva or tear flow in a total of 62% of APS-I patients. Serum IgG from 9 of 12 patients bound to targets in salivary gland biopsy slides, although the specificity and pattern of binding varied. There was no reactivity against known Sjögren-associated autoantigens in sera from APS-I patients using quantitative methods, but 11% were ANA positive by immunofluorescence microscopy. We identified several putative autoantigens in one patient, although none of these were verified as APS-I specific. We conclude that impaired salivary gland activity is part of the clinical picture of APS-I and our findings could indicate an autoimmune aetiology. We further show that APS-I patients have an altered antimicrobial signature in both sera and saliva, which requires further investigations.