Introduction: Appraising the quality of studies included in systematic reviews combining qualitative, quantitative and mixed methods studies is challenging. To address this challenge, a critical appraisal tool was developed: the Mixed Methods Appraisal Tool (MMAT). The aim of this paper is to present the MMAT. Development: The MMAT was developed in 2006 and was subject to pilot and interrater reliability testing. A revised new version of the MMAT was developed using the results from usefulness testing as well as a literature review on critical appraisal tools and a modified e-Delphi study with methodological experts to identify the core relevant criteria to include in the MMAT. Tool description: The MMAT includes quality criteria of five categories of study designs: (a) qualitative, (b) randomized controlled trial, (c) nonrandomized, (d) quantitative descriptive and (e) mixed methods studies. The MMAT focuses on core relevant methodological criteria and has five criteria per category of study design. Conclusion: The MMAT offers an alternative solution by proposing a unique tool that can appraise the quality of different study designs. Also, by limiting to core criteria, the MMAT can provide a more time efficient appraisal.

Aim COVID‐19 is associated with an exacerbated inflammatory response that can result in fatal outcomes. Systemic inflammation is also a main characteristic of periodontitis. Therefore, we investigated the association of periodontitis with COVID‐19 complications. Materials and Methods A case–control study was performed using the national electronic health records of the State of Qatar between February and July 2020. Cases were defined as patients who suffered COVID‐19 complications (death, ICU admissions or assisted ventilation), and controls were COVID‐19 patients discharged without major complications. Periodontal conditions were assessed using dental radiographs from the same database. Associations between periodontitis and COVID 19 complications were analysed using logistic regression models adjusted for demographic, medical and behaviour factors. Results In total, 568 patients were included. After adjusting for potential confounders, periodontitis was associated with COVID‐19 complication including death (OR = 8.81, 95% CI 1.00–77.7), ICU admission (OR = 3.54, 95% CI 1.39–9.05) and need for assisted ventilation (OR = 4.57, 95% CI 1.19–17.4). Similarly, blood levels of white blood cells, D‐dimer and C Reactive Protein were significantly higher in COVID‐19 patients with periodontitis. Conclusion Periodontitis was associated with higher risk of ICU admission, need for assisted ventilation and death of COVID‐19 patients, and with increased blood levels of biomarkers linked to worse disease outcomes.

A cross-sectional survey was carried out. This involved 652 out of a total of 764 (85%) 13-year-old adolescents enrolled in private and public schools located in urban areas in Cianorte, Brazil. They were interviewed and examined for traumatic dental injuries by one trained examiner (B.N.) using validated criteria. Sociodemographic data included sex, family structure (nuclear families, single parents and step-parents) and socio-economic indicators. Anthropometric measures included height and weight. The body mass index (BMI) was calculated (mean=20.1; SD=3.7). Those who had BMI scores equal or above the 85% percentile were considered overweight (BMI >23). The prevalence of traumatic injuries to the permanent incisors was 20.4%. The most common reported cause of injuries to the permanent incisors was falls (24.1%) followed by collisions with people or inanimate objects (15%), traffic accidents (10.5%), misuse of the teeth (6%), sports (2.3%) and violence (1.5%). Unknown causes accounted for 40.6%. Children from non-nuclear families, overweight children and boys were 2.18, 1.93 and 2.19 times respectively more likely to have dental injuries than children from nuclear families, non-overweight children and girls (P<0.01) after adjusting for family structure, BMI, sex, family income and level of education of the parents. The relationship between dental injuries and socioeconomic indicators was not statistically significant. In conclusion, being from a non-nuclear family, overweight and a boy increased the risk of having traumatic dental injury, but the relationship with socio-economic indicators was not statistically significant.

Selective serotonin reuptake inhibitors (SSRIs), the most widely used drugs for the treatment of depression, have been reported to reduce bone formation and increase the risk of bone fracture. Since osseointegration is influenced by bone metabolism, this study aimed to investigate the association between SSRIs and the risk of failures in osseointegrated implants. This retrospective cohort study was conducted on patients treated with dental implants from January 2007 to January 2013. A total of 916 dental implants in 490 patients (94 implants on 51 patients using SSRIs) were used to estimate the risk of failure associated with the use of SSRIs. Data analysis involved Cox proportional hazards, generalized estimating equation models, multilevel mixed effects parametric survival analysis, and Kaplan-Meier analysis. After 3 to 67 mo of follow-up, 38 dental implants failed and 784 succeeded in the nonusers group, while 10 failed and 84 succeeded in the SSRI-users group. The main limitation of this retrospective study was that drug compliance dose and treatment period could not be acquired from the files of the patients. The primary outcome was that compared with nonusers of SSRIs, SSRI usage was associated with an increased risk of dental implants failure (hazard ratio, 6.28; 95% confidence interval, 1.25-31.61; p = .03). The failure rates were 4.6% for SSRI nonusers and 10.6% for SSRI users. The secondary outcomes were that small implant diameters (≤4 mm; p = .02) and smoking habits (p = .01) also seemed to be associated with higher risk of implant failure. Our findings indicate that treatment with SSRIs is associated with an increased failure risk of osseointegrated implants, which might suggest a careful surgical treatment planning for SSRI users.

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Obesity has become a worldwide health burden in the last two decades. Obesity has been associated with increased comorbidities, such as coronary artery disease, diabetes, and destructive periodontal disease. Obesity is also part of a group of risk factors occurring together in an individual, which is referred to as metabolic syndrome. Clinical studies have shown higher risk for destructive periodontal disease in obesity and metabolic syndrome. However, the role of obesity and metabolic syndrome in the onset and development of destructive periodontal disease has not yet been fully understood. In this review, we discuss a working model, which focuses on interorgan inflammation as a common etiological factor for destructive periodontal disease associated with obesity and metabolic syndrome. Specifically, we suggest that elevated levels of tumor necrosis factor-α (TNF-α) or interleukin 6 (IL-6)—both adipokines and known risk factors for destructive periodontal disease—in obesity and metabolic syndrome contribute to the onset and development of destructive periodontal disease. The connections between destructive periodontal disease and systemic conditions, such as obesity or metabolic syndrome, are complex and potentially multidirectional. This review largely focuses on TNF-α and IL-6, inflammatory mediators, as potential common risk factors and does not exclude other biological mechanisms.

Proton pump inhibitors (PPIs) have a negative impact on bone accrual. Because osseointegration is influenced by bone metabolism, this study investigates the association between PPIs and the risk of osseointegrated implant failure. This retrospective cohort study included a total of 1,773 osseointegrated dental implants in 799 patients (133 implants in 58 PPIs users and 1,640 in 741 non-users) who were treated at the East Coast Oral Surgery Clinic in Moncton, Canada, from January 2007 to September 2015. Kaplan-Meier estimator was used to describe the hazard function of dental implant failure by PPIs usage. Multilevel mixed effects parametric survival analyses were used to test the association between PPIs exposure and risk of implant failure adjusting for potential confounders. The failure rates were 6.8% for people using PPIs compared to 3.2% for non-users. Subjects using PPIs had a higher risk of dental implant failure (HR = 2.73; 95% CI = 1.10-6.78) compared to those who did not use the drugs. The findings suggest that treatment with PPIs may be associated with an increased risk of osseointegrated dental implant failure.

In mixed methods studies, novice researchers need to know that qualitative and quantitative data or results sometimes diverge. However, few studies focus on this aspect of mixed methods research. The present paper aims to review the literature on divergence of qualitative and quantitative evidence, and describe examples. The prior literature reveals four strategies for taking divergence into account: reconciliation, initiation, bracketing and exclusion. Nine examples derived from empirical studies were found, and they are described. Then, a detailed example is given of how divergence was identified and explored in a pilot study of the implementation of one electronic knowledge resource on handheld computer in an academic family medicine clinic. Finally, this worked example is described in the context of a teaching exercise for novice researchers.