Systemic Metabolic Signatures of Oral Diseases.

Systemic metabolic signatures of oral diseases have been rarely investigated, and prospective studies do not exist. We analyzed whether signs of current or past infectious/inflammatory oral diseases are associated with circulating metabolites. Two study populations were included: the population-based Health-2000 (n = 6,229) and Parogene (n = 452), a cohort of patients with an indication to coronary angiography. Health-2000 participants (n = 4,116) provided follow-up serum samples 11 y after the baseline. Serum concentrations of 157 metabolites were determined with a nuclear magnetic resonance spectroscopy-based method. The associations between oral parameters and metabolite concentrations were analyzed using linear regression models adjusted for age, sex, number of teeth, smoking, presence of diabetes, and education (in Health-2000 only). The number of decayed teeth presented positive associations with low-density lipoprotein diameter and the concentrations of pyruvate and citrate. Negative associations were found between caries and the unsaturation degree of fatty acids (FA) and relative proportions of docosahexaenoic and omega-3 FAs. The number of root canal fillings was positively associated with very low-density lipoprotein parameters, such as diameter, cholesterol, triglycerides, and number of particles. Deepened periodontal pockets were positively associated with concentrations of cholesterol, triglycerides, pyruvate, leucine, valine, phenylalanine, and glycoprotein acetyls and negatively associated with high-density lipoprotein (HDL) diameter, FA unsaturation degree, and relative proportions of omega-6 and polyunsaturated FAs. Bleeding on probing (BOP) was associated with increased concentrations of triglycerides and glycoprotein acetyls, as well as decreased proportions of omega-3 and omega-6 FAs. Caries at baseline predicted alterations in apolipoprotein B-containing lipoproteins and HDL-related metabolites in the follow-up, and both caries and BOP were associated with changes in HDL-related metabolites and omega-3 FAs in the follow-up. Signs of current or past infectious/inflammatory oral diseases, especially periodontitis, were associated with metabolic profiles typical for inflammation. Oral diseases may represent a modifiable risk factor for systemic chronic inflammation and thus cardiometabolic disorders.

Phenotype Harmonization in the GLIDE2 Oral Health Genomics Consortium.

Genetic risk factors play important roles in the etiology of oral, dental, and craniofacial diseases. Identifying the relevant risk loci and understanding their molecular biology could highlight new prevention and management avenues. Our current understanding of oral health genomics suggests that dental caries and periodontitis are polygenic diseases, and very large sample sizes and informative phenotypic measures are required to discover signals and adequately map associations across the human genome. In this article, we introduce the second wave of the Gene-Lifestyle Interactions and Dental Endpoints consortium (GLIDE2) and discuss relevant data analytics challenges, opportunities, and applications. In this phase, the consortium comprises a diverse, multiethnic sample of over 700,000 participants from 21 studies contributing clinical data on dental caries experience and periodontitis. We outline the methodological challenges of combining data from heterogeneous populations, as well as the data reduction problem in resolving detailed clinical examination records into tractable phenotypes, and describe a strategy that addresses this. Specifically, we propose a 3-tiered phenotyping approach aimed at leveraging both the large sample size in the consortium and the detailed clinical information available in some studies, wherein binary, severity-encompassing, and "precision," data-driven clinical traits are employed. As an illustration of the use of data-driven traits across multiple cohorts, we present an application of dental caries experience data harmonization in 8 participating studies (N = 55,143) using previously developed permanent dentition tooth surface-level dental caries pattern traits. We demonstrate that these clinical patterns are transferable across multiple cohorts, have similar relative contributions within each study, and thus are prime targets for genetic interrogation in the expanded and diverse multiethnic sample of GLIDE2. We anticipate that results from GLIDE2 will decisively advance the knowledge base of mechanisms at play in oral, dental, and craniofacial health and disease and further catalyze international collaboration and data and resource sharing in genomics research.

Virtual Reality Relaxation to Decrease Dental Anxiety: Immediate Effect Randomized Clinical Trial.

INTRODUCTION: Dental anxiety is common and causes symptomatic use of oral health services. OBJECTIVES: The aim was to study if a short-term virtual reality intervention reduced preoperative dental anxiety. METHODS: A randomized controlled single-center trial was conducted with 2 parallel arms in a public oral health care unit: virtual reality relaxation (VRR) and treatment as usual (TAU). The VRR group received a 1- to 3.5-min 360° immersion video of a peaceful virtual landscape with audio features and sound supporting the experience. TAU groups remained seated for 3 min. Of the powered sample of 280 participants, 255 consented and had complete data. Total and secondary sex-specific mixed effects linear regression models were completed for posttest dental anxiety (Modified Dental Anxiety Scale [MDAS] total score) and its 2 factors (anticipatory and treatment-related dental anxiety) adjusted for baseline (pretest) MDAS total and factor scores and age, taking into account the effect of blocking. RESULTS: Total and anticipatory dental anxiety decreased more in the VRR group than the TAU group (ß = -0.75, P < .001, for MDAS total score; ß = -0.43, P < .001, for anticipatory anxiety score) in patients of a primary dental care clinic. In women, dental anxiety decreased more in VRR than TAU for total MDAS score (ß = -1.08, P < .001) and treatment-related dental anxiety (ß = -0.597, P = .011). Anticipatory dental anxiety decreased more in VRR than TAU in both men (ß = -0.217, P < .026) and women (ß = -0.498, P < .001). CONCLUSION: Short application of VRR is both feasible and effective to reduce preoperative dental anxiety in public dental care settings (ClinicalTrials.gov NCT03993080). KNOWLEDGE TRANSFER STATEMENT: Dental anxiety, which is a common problem, can be reduced with short application of virtual reality relaxation applied preoperatively in the waiting room. Findings of this study indicate that it is a feasible and effective procedure to help patients with dental anxiety in normal public dental care settings.

The impact of oral appliance therapy with moderate mandibular advancement on obstructive sleep apnea and upper airway volume.

PURPOSE: To find out if a moderate protrusion with a mandibular advancement device (MAD) can significantly increase the upper airway volume and, further, what signs and symptoms of obstructive sleep apnea (OSA) can be improved by this maneuver. METHODS: There were 58 adults diagnosed with OSA who were referred for MAD therapy. The mean apnea-hypopnea index (AHI) was 19.2 (SD 8.6). Five indicators of signs and symptoms of OSA (AHI, oxygen saturation, snoring, daytime sleepiness, and health-related quality of life) were evaluated at the baseline and after 6 months of MAD therapy. Nasal resistance and airway volume and cross-sectional areas with and without the MAD in situ were recorded. Based on AHI reduction, the treatment response was classified as complete, partial, or non-complete. Statistical analyses included the chi-square, t tests, Mann-Whitney U tests, and regression analyses (linear and logistic). RESULTS: Twenty-three patients attained a complete response (residual AHI < 5 events/h) to MAD therapy. In 13 subjects, the response was partial, and in 9 patients, it was non-complete. The complete responders were significantly younger, and they had a deeper overbite than partial/non-complete responders. A convex profile associated positively, but a vertically restricted throat and increased lower facial height associated negatively with the increase in airway volume. CONCLUSIONS: Excellent MAD therapy outcomes were achieved in most patients. Only age and deep bite had some influence on AHI reduction, indicating multifactorial nature in the response to MAD therapy.

The Finnish psychiatric birth cohort consortium (PSYCOHORTS) - content, plans and perspectives.

Background: Psychiatric disorders tend to be developmental, and longitudinal settings are required to examine predictors of psychiatric phenomena. Replicating and combining data and results from different birth cohorts, which are a source of reliable data, can make research even more valuable. The Finnish Psychiatric Birth Cohort Consortium (PSYCOHORTS) project combines birth cohorts in Finland. Aim: The aim of this paper is to introduce content, plans and perspectives of the PSYCOHORTS project that brings together researchers from Finland. In addition, we illustrate an example of data harmonization using available data on causes of death. Content: PSYCOHORTS includes eight Finnish birth cohorts. The project has several plans: to harmonize different data from birth cohorts, to incorporate biobanks into psychiatric birth cohort research, to apply multigenerational perspectives, to integrate longitudinal patterns of marginalization and inequality in mental health, and to utilize data in health economics research. Data on causes of death, originally obtained from Finnish Cause of Death register, were harmonized across the six birth cohorts using SAS macro facility. Results: Harmonization of the cause of death data resulted in a total of 21,993 observations from 1965 to 2015. For example, the percentage of deaths due to suicide and the sequelae of intentional self-harm was 14% and alcohol-related diseases, including accidental poisoning by alcohol, was 13%. Conclusions: PSYCOHORTS lays the foundation for complex examinations of psychiatric disorders that is based on compatible datasets, use of biobanks and multigenerational approach to risk factors, and extensive data on marginalization and inequality.

Neurosensory recovery after trauma to the orbital floor: a prospective trial with dexamethasone.

Our aims were to document the occurrence of neurosensory disturbances of the infraorbital nerve six months after operation for an orbital blow-out fracture, and to find out whether dexamethasone facilitates neurosensory regeneration. Patients were randomly assigned to one of two groups: the study group was given a total of dexamethasone 30mg, whereas the control group were given neither glucocorticoid nor placebo. Each patient's infraorbital neurosensory state was recorded preoperatively, immediately postoperatively, and six months later. A total of 18 patients were included, eight of whom had neurosensory disturbances six months after the initial trauma that was not affected by dexamethasone. Six of the seven patients who had a delay of seven days or more between trauma and operation had significantly prolonged disturbance at the 180-day clinical follow up compared with those in whom it was less than seven days (p=0.005). Other possible predictors made no significant difference. Although dexamethasone did not facilitate sensory recovery, its benefits in the management of pain and reduction of swelling may justify its use in the management of facial trauma in selected patients.

Fifth-year dental students' visions of leadership-A qualitative study.

INTRODUCTION: Leadership skills are important in dentists' work. Leadership education already in undergraduate curriculum is noteworthy. The aim of this qualitative study was to describe dental students' visions of leadership: how they imagined they end up in leadership position, factors supporting either staying in or leaving the position and their future views. MATERIALS AND METHODS: The data were gathered after participants, fifth-year dental students, attended a "Dentist as a Leader" study module. A method of empathy-based stories was utilised. Based on contrasting frame stories, students were divided into two groups and wrote essays about an imagined situation in which they either enjoyed their leadership position ("Stayers") or considered leaving it ("Leavers"). The data were analysed using the content analysis method. RESULTS: The reasons for ending up in a leadership position were similar in the two groups: accidentally drifting into or intentionally heading for it. Factors supporting staying or leaving the leadership position were more diverse and were divided into personal and working community levels. These factors were common and group-specific. Clinical work, personal life and the ability to improve the organisations were common factors. Good working community was a "Stayer"-specific factor. "Leaver"-specific factors included loneliness, stress and lack of public sector resources. Future career plans were similar in both groups emphasising clinical work. CONCLUSIONS: After having attended leadership training, dental students were able to describe their future careers and list factors supporting either staying or leaving an imagined leadership position. These factors can be utilised by organisations to develop better working environments for future dentist leaders. By recognising the factors, students themselves are able to plan their future career choices and prepare to become leaders.

Efficacy of stabilisation splint treatment on the oral health-related quality of life-A randomised controlled one-year follow-up trial.

The aim of this randomised controlled trial was to assess the efficacy of stabilisation splint treatment on the oral health-related quality of life OHRQoL during a 1-year follow-up. Originally, the sample consisted of 80 patients (18 men, 62 women) with temporomandibular disorders (TMD) who had been referred to the Oral and Maxillofacial Department, Oulu University Hospital, Finland, for treatment. Patients were randomly designated into splint (n = 39) and control group (n = 41). Patients in the splint group were treated with a stabilisation splint. Additionally, patients in both groups received counselling and instructions on masticatory muscle exercises. The patients filled in the Oral Health Impact Profile-14 (OHIP-14) questionnaire before treatment and at 3 months, 6 months and 1 year. At total, 67 patients (35 in the splint group vs. 32 in the control group) completed the questionnaire at baseline. The outcome variables were OHIP prevalence, OHIP severity and OHIP extent. Linear mixed-effect regression model was used to analyse factors associated with change in OHIP severity during the 1-year follow-up, taking into account treatment time, age, gender and group status. OHIP prevalence, severity and extent decreased in both groups during the follow-up. According to linear mixed-effect regression, decrease in OHIP severity did not associate significantly with group status. Compared to masticatory muscle exercises and counselling alone, stabilisation splint treatment was not more beneficial on self-perceived OHRQoL among TMD patients over a 1-year follow-up.

Factors supporting dentist leaders' retention in leadership.

OBJECTIVE: The aim was to study factors associated with staying in a dentist leadership position. PARTICIPANTS AND METHODS: We used an electronic questionnaire to gather data from 156 current or former Finnish dentist leaders in 2014. Principal component analysis categorized statements regarding time usage and opportunities in managerial work into five main components. Associations between these main component scores and the tendency to stay as a leader were analyzed with logistic regression. RESULTS: Out of the five main components, two were significantly associated with staying as a leader: 'career intentions', which represented intent to continue or to leave the leadership position; and 'work time control opportunities', which represented how leaders could control their own work time. Other factors that supported staying were leadership education, more work time available for leadership work, and lower age. The main component 'work pressure' decreased, although not significantly, the odds of continuing; it included lack of leadership work time, and pressure from superiors or subordinates. CONCLUSIONS: Leaders have important roles in health care, ensuring everyday operations as well as developing their organizations to meet future challenges. Knowledge of these supporting factors will enable dentist leaders and their organizations to improve working conditions in order to recruit and retain motivated and competent persons. In addition, well-designed education is important to inspire and encourage future leaders.

Signs of disease occur in the majority of third molars in an adult population.

The purpose of this study was to assess clinical and radiographic signs of disease in third molars within a population that is representative of the Finnish adult population aged 30 years and older. A two-stage stratified cluster sampling method was used to collect the 6005 subjects, who were examined clinically and also by panoramic radiography. The state of impaction, presence of dentinal caries and/or restorations, presence of root canal fillings, periodontal pocket depth, and additional pathological findings such as over-eruption and widened follicle were assessed. Signs of disease in the third molars were found in 47% of the adult population and in 97% of those subjects with third molars. At least one sign of disease occurred in 82% of erupted third molars compared to 74% of those impacted in soft tissue and 33% impacted in bone (P<0.001). A diseased third molar was more often located in the mandible (60%) than in the maxilla (40%) (P<0.001), and was more often found in men (57%) than in women (43%) (P<0.05). It is concluded that signs of disease in third molars in the target population are more common than has been reported previously.

Postoperative nausea and vomiting in facial fracture patients: A Randomized and controlled trial on the effect of dexamethasone.

This study aimed to establish the incidence of postoperative nausea and vomiting (PONV) in facial fracture patients. The specific aim was to investigate the effect of perioperative dexamethasone on PONV. A total of 119 adult patients with facial fractures were analysed in this prospective study. Patients were randomized to receive perioperatively either a total dose of 30mg of dexamethasone i.v. and i.m., or no glucocorticoid (control). PONV was evaluated every 6hours during the first postoperative 24hours and when pain medications were given. PONV occurred in 20 out of 119 patients (16.8%). The only significant (P=0.016) association with PONV was postoperative administration of opioids. Slightly more cases of PONV occurred for patients who had not received dexamethasone (20%) compared to those who had (13.6%). PONV was also non-significantly more common in patients ≥40 years (21.3%) than in patients < 40 years (12.1%), after orbital floor reconstruction (28.0%) compared with mandibular (11.6%) and zygomatic (15.6%) fractures surgeries, and also after anaesthesia lasting >97minutes (21.7%) compared with a shorter duration (11.3%). Alternative medications should be used for prevention of post-surgery nausea and vomiting in facial fracture patients.

Food Consumption and Nutrient Intake in Relation to Denture Use in 55- to 84-Year-Old Men and Women -Results of a Population Based Survey.

OBJECTIVE: To study differences in consumption of foods and intake of nutrients attributable to denture status. DESIGN, SETTING AND PARTICIPANTS: Data from a cross-sectional, nationally representative Health 2000 Survey, subjects aged 55-84 years (n=2,241). MEASUREMENTS: Denture status (edentulous with full dentures, own dentition with removable dentures, own dentition with no removable dentures) was used as an explanatory variable. The consumption of foods and intake of nutrients was used as an outcome variable and was measured using a validated Food Frequency Questionnaire. RESULTS: Denture status associated with food choices. Full denture wearers consumed less vegetables (p = 0.013 among men and p = 0.001 among women) and fruits (p = 0.001 among women), more sugary products (p = 0.012 among men and p = 0.008 among women), and their balance in fatty acids was less favourable than among dentate participants. Among dentate participants, the differences between the two groups were small and statistically significant differences were seen mostly in women. CONCLUSIONS: Wearing full dentures appears to be associated with unhealthier food choices, lower consumption of some foodstuffs and lower intake of certain nutrients when compared to the food choices of dentate persons.

Dexamethasone in head and neck cancer patients with microvascular reconstruction: No benefit, more complications.

OBJECTIVES: Glucocorticoids are widely used in association with major surgery of the head and neck to improve postoperative rehabilitation, shorten intensive care unit and hospital stay, and reduce neck swelling. This study aimed to clarify whether peri- and postoperative use of dexamethasone in reconstructive head and neck cancer surgery is associated with any advantages or disadvantages. MATERIALS AND METHODS: This prospective double-blind randomized controlled trial comprised 93 patients. A total dose of 60mg of dexamethasone was administered to 51 patients over three days peri- and postoperatively. The remaining 42 patients served as controls. The main primary outcome variables were neck swelling, length of intensive care unit and hospital stay, duration of intubation or tracheostomy, and delay to start of possible radiotherapy. Complications were also recorded. RESULTS: No statistical differences emerged between the two groups in any of the main primary outcome variables. However, there were more major complications, especially infections, needing secondary surgery within three weeks of the operation in patients receiving dexamethasone than in control patients (27% vs. 7%, p=0.012). CONCLUSIONS: The use of dexamethasone in oral cancer patients with microvascular reconstruction did not provide a benefit. More major complications, especially infections, occurred in patients receiving dexamethasone. Our data thus do not support the use of peri- and postoperative dexamethasone in oropharyngeal cancer patients undergoing microvascular reconstruction.

Prevalence of apical periodontitis in root filled teeth: findings from a nationwide survey in Finland.

AIM: To assess the prevalence of apical periodontitis in the Finnish population aged 30 years and older and relate it to the technical quality of root filling by the type of tooth. METHODOLOGY: As part of the Finnish nationwide Health 2000 study, panoramic radiographs were used of the dentate subjects (n = 5335) aged 30-95 years (mean 50.2 years) to assess the apical and endodontic status of their teeth (n = 120635). Apical periodontitis (AP) was recorded when the periodontal ligament space was more than double in width, or loss of lamina dura or a periapical radiolucent lesion was seen. Technically, adequate root fillings had a gap of 0-3 mm from the apex; all others were defined as inadequate. Statistical methods included chi-square tests and anova. Risk of AP was estimated as cross-product odds ratio and its 95% confidence interval. RESULTS: Teeth with AP occurred in 27% of the dentate subjects being more prevalent in subjects with root filled teeth than in those without (39% vs. 9%; P < 0.001; OR = 6.3; 95% CI 5.3, 7.4). AP was more prevalent in men than in women (31% vs. 23%). At a tooth level, AP was most frequent in mandibular molars with inadequate root fillings. For all root filled teeth, an inadequate root filling doubled the risk of AP for both women (OR = 2.0; 95% CI 1.7, 2.4) and men (OR = 2.5; 95% CI 2.1, 2.9). CONCLUSIONS: AP occurred principally in subjects and teeth with root fillings. Inadequate root fillings doubled the risk of AP. An improvement in the technical quality of root canal treatment is essential.

Role of Employment in 11-Year Changes of Clinical Oral Health: A Multilevel Longitudinal Analysis.

The objective was to investigate the role of employment in the 11-y changes of clinically determined oral health. We used data from the longitudinal Health 2011 Survey, including reinvited subjects from the Health 2000 Survey. Data were gathered by clinical oral examinations, interviews, and questionnaires of those aged 30 to 63 y ( n = 1,031) in 2000. Exposures were change in employment from baseline to follow-up and length of unemployment. Outcomes measures were the numbers of missing teeth, sound teeth, filled teeth, decayed teeth, and teeth with periodontal pockets (≥4 mm and ≥6 mm). Separate mixed-effects and conventional negative binomial regression models were fitted for each oral health outcome. Demographic, socioeconomic, and oral health-related behaviors were added as covariates to the analyses. The findings showed that unemployment was inconsistently associated with poorer clinically determined oral health over 11 y. These effects were attributed to income and education and, to a lesser extent, to oral health-related behaviors. The length of unemployment was also inconsistently associated with oral health. The study concluded that one socioeconomic factor, unemployment, had a partial impact on oral health. Knowledge Transfer Statement: The findings of this study can help clinicians and oral health policy makers to reorient oral health services toward those who are unemployed as a risk group for poor oral health. The research highlights the role of employment in the longitudinal changes of clinically determined oral health, taking into consideration other socioeconomic factors. The study concluded that unemployment seemed to have a role in social inequalities of oral health.

Mannose-binding lectin gene polymorphism in relation to periodontal infection.

BACKGROUND AND OBJECTIVE: Mannose-binding lectin (MBL) plays an important role in innate immunity. MBL deficiency is usually caused by mutations in exon 1 of the MBL structural gene (MBL2). Our aim was to investigate MBL2 polymorphisms and their relation to salivary levels of periodontal inflammatory/tissue destruction markers and two major periodontitis-associated bacteria. MATERIAL AND METHODS: Salivary samples from 222 subjects were available for genotyping by pyrosequencing. The subjects between 40 and 60 years of age and having a minimum of 20 teeth were divided into three periodontal groups: 80 had generalized periodontitis, 65 had localized periodontitis and 77 were periodontitis-free. A comparison between their MBL2 genotypes and salivary detection rates and levels of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis as well as interleukin -1ß, matrix metalloproteinase -8, and tissue inhibitor of matrix metalloproteinase (TIMP)-1 was performed. RESULTS: The frequencies of the MBL2 wild-type (A/A), heterozygote variants (A/O) and homozygote variants (O/O) were 69.4%, 26.6% and 4%, respectively. In A. actinomycetemcomitans-positive subjects having homozygote or heterozygote MBL2 variants, the salivary concentrations of IL-1ß (p = 0.010) were elevated and those of TIMP-1 (p = 0.001) were decreased. In addition their matrix metalloproteinase -8/TIMP-1 ratio was higher (p < 0.001) and they had more pocket teeth (p = 0.012) than subjects negative for A. actinomycetemcomitans. CONCLUSION: Our findings indicate that the carriage of A. actinomycetemcomitans may facilitate extended periodontal inflammation and destruction in subjects with a variant form of human MBL2.

Association between oral health habits and dental caries among children in Pyongyang, Democratic People's Republic of Korea.

AIM: To evaluate the self-reported oral health habits and their association with the occurrence of dental caries among children in Pyongyang, Democratic People's Republic of Korea (DPRK), after 6 years of activities under the auspices of the Children's Oral Health Promotion Programme (COHPP). METHODS: The data were collected in September 2013 in two of the most central districts of Pyongyang City, DPRK. The sample consisted of 492 children aged 10 and 13 years who had participated in the COHPP for 6 years. The children filled in a self-completed, structured questionnaire on oral health habits and were examined clinically by a dentist. The differences in mean (SD) number of decayed primary (dt) and permanent teeth (DT) and their sum (dt + DT) subdivided according to genders, age groups, districts and self-reported oral health habits were evaluated using Mann-Whitney U-test. The associations between self-reported oral health habits and the occurrence of dental caries were evaluated with chi-square test and logistic regression analyses. RESULTS: The school-aged children commonly reported healthy oral hygiene habits but sweet snacks were commonly used. The occurrence of dental caries associated statistically significantly with the frequency of sweet snacking (p=0.011) but not with the frequency of tooth brushing (p=0.725) or the use of water for thirst instead of sugary beverages (p=0.189). CONCLUSION: A more effective promotion of healthy dietary habits with innovative approaches and close collaboration with different social actors will be needed in future.

Comparison of two preventive interventions on dental caries among children in Democratic People's Republic of Korea.

OBJECTIVES: The aim was to compare the change in dental caries status in two different intervention groups of the Children's Oral Health Promotion Programme (COHPP). METHODS: A longitudinal study among 500 children who had participated into the COHPP for 6 years was conducted in Pyongyang, Democratic People's Republic of Korea (DPRK). Children in Group I received intensified school-based intervention and were clinically examined at the age of 7 years in 2007 (n = 250), 10 years in 2010 (n = 250) and 13 years in 2013 (n = 242). Children in Group II (n = 250) joined the programme at the age of 4 years in kindergarten in 2007, were provided with early preschool-based intervention and were clinically examined at the age of 7 years in 2010 and 10 years in 2013. RESULTS: Both the prevalence and the mean number of dt + DT decreased significantly in both groups during the follow-up. This was due to decrease in the number of dt, whereas the number of DT remained relatively constant. Poisson regression showed that the association between the group status and the change in the number of dt + DT was statistically significant when adjusted for gender but disappeared when the school was included in the analysis. CONCLUSIONS: The decrease in dental caries may be partly due to the exfoliation of deciduous teeth and dental treatment received. However, the study gave some reference emphasizing the early starting of the prevention.

ViPAR: a software platform for the Virtual Pooling and Analysis of Research Data.

BACKGROUND: Research studies exploring the determinants of disease require sufficient statistical power to detect meaningful effects. Sample size is often increased through centralized pooling of disparately located datasets, though ethical, privacy and data ownership issues can often hamper this process. Methods that facilitate the sharing of research data that are sympathetic with these issues and which allow flexible and detailed statistical analyses are therefore in critical need. We have created a software platform for the Virtual Pooling and Analysis of Research data (ViPAR), which employs free and open source methods to provide researchers with a web-based platform to analyse datasets housed in disparate locations. METHODS: Database federation permits controlled access to remotely located datasets from a central location. The Secure Shell protocol allows data to be securely exchanged between devices over an insecure network. ViPAR combines these free technologies into a solution that facilitates 'virtual pooling' where data can be temporarily pooled into computer memory and made available for analysis without the need for permanent central storage. RESULTS: Within the ViPAR infrastructure, remote sites manage their own harmonized research dataset in a database hosted at their site, while a central server hosts the data federation component and a secure analysis portal. When an analysis is initiated, requested data are retrieved from each remote site and virtually pooled at the central site. The data are then analysed by statistical software and, on completion, results of the analysis are returned to the user and the virtually pooled data are removed from memory. CONCLUSIONS: ViPAR is a secure, flexible and powerful analysis platform built on open source technology that is currently in use by large international consortia, and is made publicly available at [http://bioinformatics.childhealthresearch.org.au/software/vipar/].

The Shape of the Dose-Response Relationship between Sugars and Caries in Adults.

Dental caries is considered a diet-mediated disease, as sugars are essential in the caries process. However, some gaps in knowledge about the sugars-caries relationship still need addressing. This longitudinal study aimed to explore 1) the shape of the dose-response association between sugars intake and caries in adults, 2) the relative contribution of frequency and amount of sugars intake to caries levels, and 3) whether the association between sugars intake and caries varies by exposure to fluoride toothpaste. We used data from 1,702 dentate adults who participated in at least 2 of 3 surveys in Finland (Health 2000, 2004/05 Follow-up Study of Adults' Oral Health, and Health 2011). Frequency and amount of sugars intake were measured with a validated food frequency questionnaire. The DMFT index was the repeated outcome measure. Data were analyzed with fractional polynomials and linear mixed effects models. None of the 43 fractional polynomials tested provided a better fit to the data than the simpler linear model. In a mutually adjusted linear mixed effects model, the amount of, but not the frequency of, sugars intake was significantly associated with DMFT throughout the follow-up period. Furthermore, the longitudinal association between amount of sugars intake and DMFT was weaker in adults who used fluoride toothpaste daily than in those using it less often than daily. The findings of this longitudinal study among Finnish adults suggest a linear dose-response relationship between sugars and caries, with amount of intake being more important than frequency of ingestion. Also, daily use of fluoride toothpaste reduced but did not eliminate the association between amount of sugars intake and dental caries.