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Introduction The current COVID-19 pandemic caused by the SARS-CoV-2 virus has impacted the delivery of dental care globally and has led to re-evaluation of infection control standards. However, lack of clarity around what is known and unknown regarding droplet and aerosol generation in dentistry (including oral surgery and extractions), and their relative risk to patients and the dental team, necessitates a review of evidence relating to specific dental procedures. This review is part of a wider body of research exploring the evidence on bioaerosols in dentistry and involves detailed consideration of the risk of contamination in relation to oral surgery. Methods A comprehensive search of Medline (OVID), Embase (OVID), Cochrane Central Register of Controlled Trials, Scopus, Web of Science, LILACS and ClinicalTrials.Gov was conducted using key terms and MeSH (Medical Subject Headings) words relating to the review questions. Methodological quality including sensitivity was assessed using a schema developed to measure quality aspects of studies using a traffic light system to allow inter- and intra-study overview and comparison. A narrative synthesis was conducted for assessment of the included studies and for the synthesis of results. Results Eleven studies on oral surgery (including extractions) were included in the review. They explored microbiological (bacterial and fungal) and blood (visible and/or imperceptible) contamination at the person level (patients, operators and assistants) and/or at a wider environmental level, using settle plates, chemiluminescence reagents or air samplers; all within 1 m of the surgical site. Studies were of generally low to medium quality and highlighted an overall risk of contaminated aerosol, droplet and splatter generation during oral surgery procedures, most notably during removal of impacted teeth using rotatory handpieces. Risk of contamination and spread was increased by factors, including proximity to the operatory site, longer duration of treatment, higher procedural complexity, non-use of an extraoral evacuator and areas involving more frequent contact during treatment. Conclusion A risk of contamination (microbiological, visible and imperceptible blood) to patients, dental team members and the clinical environment is present during oral surgery procedures, including routine extractions. However, the extent of contamination has not been explored fully in relation to time and distance. Variability across studies with regards to the analysis methods used and outcome measures makes it difficult to draw robust conclusions. Further studies with improved methodologies, including higher test sensitivity and consideration of viruses, are required to validate these findings.

Background Children with learning disabilities (CLD) have worse health outcomes than children with no learning disabilities (CNLD). This systematic review compared caries experience and met dental care need for CLD to CNLD using Decayed, Missing, Filled Permanent Teeth (DMFT) and decayed, missing/extracted, filled primary teeth (dmft/deft), care index (CI), and restorative index (RI) values. Methods Without date or language restrictions four databases were searched for; cross-sectional studies comparing caries experience and CI/ RI in CLD matched to groups of CNLD. Screening and data extraction were carried out independently and in duplicate. Risk of bias was assessed using the Newcastle-Ottawa Scale. Meta-analyses were carried out (random effects model). Results There were 25 articles with 3976 children (1 to 18 years old), from 18 countries, fitting the inclusion criteria. Children with; Down syndrome were investigated in 11 studies, autism in 8 and mixed learning disabilities in 6. The overall mean DMFT for CLD was 2.31 (standard deviation±1.97; range 0.22 to 7.2) and for CNLD was 2.51 (±2.14; 0.37 to 4.76). Using standardised mean difference (SMD), meta-analysis showed no evidence of a difference between CLD and CNLD ( n = 16 studies) for caries experience (SMD = -0.43; 95%CI = -0.91 to 0.05). This was similar for sub-groups of children with autism (SMD = -0.28; 95%CI = 1.31 to 0.75) and mixed disabilities (SMD = 0.26; 95%CI = -0.94 to 1.47). However, for children with Down syndrome, caries experience was lower for CLD than CNLD (SMD = -0.73; 95%CI = -1.28 to − 0.18). For primary teeth, mean dmft/deft was 2.24 for CLD and 2.48 for CNLD ( n = 8 studies). Meta-analyses showed no evidence of a difference between CLD and CNLD for caries experience across all disability groups (SMD = 0.41; 95% CI = -0.14 to 0.96), or in sub-groups: Down syndrome (SMD = 0.55; 95%CI- = − 0.40 to 1.52), autism (SMD = 0.43; 95%CI = -0.53 to 2.39) and mixed disabilities (SMD = -0.10; 95%CI = -0.34 to 0.14). The studies’ risk of bias were medium to high. Conclusion There was no evidence of a difference in caries levels in primary or permanent dentitions for CLD and CNLD. This was similar for learning disability sub-groups, except for Down syndrome where dental caries levels in permanent teeth was lower. Data on met need for dental caries was inconclusive. Trial registration The protocol was published in PROSPERO: CRD42017068964 (June 8th, 2017). Electronic supplementary material The online version of this article (10.1186/s12903-019-0795-4) contains supplementary material, which is available to authorized users.

Introduction: Against the COVID-19 pandemic backdrop and potential disease transmission risk by dental procedures that can generate aerosol and droplets. Objectives: This review aimed to identify which clinical dental procedures do generate droplets and aerosols with subsequent contamination, and for these, characterise their pattern, spread and settle. Materials and Method: Six databases were searched and citation chasing undertaken (to 11/08/20). Screening stages were undertaken in duplicate, independently, by two researchers. Data extraction was performed by one reviewer and verified by another. Results: Eighty-three studies met the inclusion criteria and covered: Ultrasonic scaling (USS, n=44), high speed air-rotor (HSAR, n=31); oral surgery (n=11), slow-speed handpiece (n=4); air-water (triple) syringe (n=4), air-polishing (n=4), prophylaxis (n=2) and hand-scaling (n=2). Although no studies investigated respiratory viruses, those on bacteria, blood splatter and aerosol showed activities using powered devices produced the greatest contamination. Contamination was found for all activities, and at the furthest points studied. The operator torso operator arm, and patient body were especially affected. Heterogeneity precluded significant inter-study comparisons but intra-study comparisons allowed construction of a proposed hierarchy of procedure contamination risk: higher risk (USS, HSAR, air-water syringe [air only or air/water together], air polishing, extractions using motorised hand-pieces); moderate (slow-speed handpieces, prophylaxis with pumice, extractions) and lower (air-water syringe [water only] and hand scaling. Conclusion: Significant gaps in the evidence, low sensitivity of measures and variable quality limit firm conclusions around contamination for different procedures. However, a hierarchy of contamination from procedures can be proposed for challenge/verification by future research which should consider standardised methodologies to facilitate research synthesis. Clinical significance (49 words): This manuscript addresses uncertainty around aerosol generating procedures (AGPs) in dentistry. Findings indicate a continuum of procedure-related aerosol generation rather than the current binary AGP or non-AGP perspective. This informs discussion around AGPs and direct future research to help support knowledge and decision making around COVID-19 and dental procedures.

Introduction The emergence of the SARS-CoV-2 virus and subsequent COVID-19 pandemic has had a significant effect on the delivery of routine dentistry; and in particular, periodontal care across the world. This systematic review examines the literature relating to splatter, droplet settle and aerosol for periodontal procedures and forms part of a wider body of research to understand the risk of contamination in relation to periodontal care procedures relevant to COVID-19. Methods A search of the literature was carried out using key terms and MeSH words relating to the review questions. Sources included Medline (OVID), Embase (OVID), Cochrane Central Register of Controlled Trials, Scopus, Web of Science and LILACS, ClinicalTrials.Gov. Studies meeting inclusion criteria were screened in duplicate and data extraction was carried out using a template. All studies were assessed for methodological quality and sensitivity. Narrative synthesis was undertaken. Results Fifty studies were included in the review with procedures including ultrasonic scaling (n = 44), air polishing (n = 4), prophylaxis (n = 2) and hand scaling (n = 3). Outcomes included bacterial (colony-forming units e.g. on settle plates) or blood contamination (e.g. visible splatter) and non bacterial, non blood (e.g. chemiluminescence or coloured dyes) contamination. All studies found contamination at all sites although the contamination associated with hand scaling was very low. Contamination was identified in all of the studies even where suction was used at baseline. Higher power settings created greater contamination. Distribution of contamination varied in relation to operator position and was found on the operator, patient and assistant with higher levels around the head of the operator and the mouth and chest of the patient. Settle was identified 30 min after treatments had finished but returned to background levels when measured at or after an hour. The evidence was generally low to medium quality and likely to underestimate contamination. Conclusion Ultrasonic scaling, air polishing and prophylaxis procedures produce contamination (splatter, droplets and aerosol) in the presence of suction, with a small amount of evidence showing droplets taking between 30 min and 1 h to settle. Consideration should be given to infection control, areas of cleaning particularly around the patient and appropriate personal protective equipment, with particular attention to respiratory, facial and body protection for these procedures. In addition, the use of lower power settings should be considered to reduce the amount and spread of contamination.

SYNOPSIS European life insurers began disclosing embedded value information (EV) over a decade ago due to concerns with traditional local accounting standards. EV is an estimate of the present value of future net cash flows from in-force life insurance business. However, U.S.-based life insurers have yet to adopt this disclosure, although several surveys and empirical studies suggest that EV disclosure provides valuable information in assessing life insurers' performance. This paper examines the incremental valuation effects of EV disclosure in the presence of U.S. GAAP. We utilize a sample of cross-listed life insurers as surrogates to assess the valuation effects of EV disclosures for U.S. life insurers. Our empirical results show a higher association between EV and stock market prices than those of traditional accounting metrics such as earnings or book value. The results also show that EV has incremental explanatory power beyond those of traditional U.S. GAAP accounting measures. Our findings provide vital input to FASB and IASB as they currently engage in a joint project to develop uniform globally acceptable, comparable accounting standards for life insurers.

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