ABSTRACTS

Measures to reduce the clinical need for dental amalgam: an evidence review

Keane, M., Lee, C., Long, J.

International binding agreements oblige signatories, including Ireland, to reduce their use of mercury to protect the environment. In response, the Irish Government needs to phase out the use of dental amalgam by 2030. The aim of this evidence review was to examine factors relevant to phasing out of amalgam and consider alternative replacement strategies for treating dental caries. We examined evidence where: a) exemptions existed to allow the use of dental amalgam; and, b) measures taken to phase out amalgam. We also drew on 101 systematic reviews to identify alternative interventions to amalgam and their effectiveness. We found that exemptions to permit the continued use of amalgam only applied when treating permanent tooth restoration. Measures to phase out dental amalgam ranged from raising public awareness of the risk to the environment, to realigning dental insurance policies to prioritise alternatives to amalgam. There is adequate evidence that: a) fluoride technologies and resin-based sealants are effective in preventing dental caries; and, b) silver diamine fluoride, sealants combined with fluoride, and microinvasive strategies are effective in early treatment of caries. Glass-ionomer cements are equal to other restorative materials for restorations in primary teeth. Composite resin formulations are considered the next best restoration alternative to amalgam.

Health Research Board, 2020. Available from: https://www.hrb.ie/fileadmin/2._Plugin_related_files/Publications/2020_pu blicationrelated_files/2020_HIE/Measures_to_reduce_the_clinical_need_for_dental_a malgam.pdf.

A review of Covid-19 vaccination and the reported cardiac manifestations

Ho, J.S., Sia, C.H., Ngiam, J.N., Loh, P.H., Chew, N.W., Kong, W.K., et al.

Abstract In Singapore, 9.03 million doses of the mRNA Covid-19 vaccines by PfizerBioNTech and Moderna have been administered, and 4.46 million people are fully vaccinated. An additional 87,000 people have been vaccinated with vaccines on the World Health Organization’s emergency use listing. The aim of this review is to explore the reported cardiac adverse events associated with different types of Covid-19 vaccines. Some 42 studies that reported cardiac side effects after Covid-19 vaccination were included in this study. Reported Covid-19 vaccine-associated cardiac adverse events were mainly myocarditis and pericarditis, most commonly seen in adolescent and young adult male individuals after mRNA vaccination. Reports of other events such as acute myocardial infarction, arrhythmia and stress cardiomyopathy were rare. Outcomes of post-vaccine myocarditis and pericarditis were good. Given the good vaccine efficacy and the high number of cases of infection, hospitalisation and death that could potentially be prevented, Covid-19 vaccine remains of overall benefit, based on the current available data.

Singapore Medical Journal 2021. DOI: 10.11622/smedj.2021210. Epub ahead of print. PMID: 34808708.

Visualizing in deceased Covid-19 patients how SARSCoV-2 attacks the respiratory and olfactory mucosae but spares the olfactory bulb

Khan, M., Yoo, S.J., Clijsters, M., Backaert, W., Vanstapel, A., Speleman, K., et al.

Abstract Anosmia, the loss of smell, is a common and often the sole symptom of Covid19. The onset of the sequence of pathobiological events leading to olfactory dysfunction remains obscure. Here, we have developed a post-mortem bedside surgical procedure to harvest endoscopically samples of respiratory and olfactory mucosae and whole olfactory bulbs. Our cohort of 85 cases included Covid-19 patients who died a few days after infection with SARS-CoV-2, enabling us to catch the virus while it was still replicating. We found that sustentacular cells are the major target cell type in the olfactory mucosa. We

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failed to find evidence for infection of olfactory sensory neurons, and the parenchyma of the olfactory bulb is spared as well. Thus, SARS-CoV-2 does not appear to be a neurotropic virus. We postulate that transient insufficient support from sustentacular cells triggers transient olfactory dysfunction in Covid-19. Olfactory sensory neurons would become affected without getting infected.

Cell 2021; 184 (24): 5932-5949.

Effectiveness of The Wikipedia Collaboration of Dental Schools’ training programme: a new paradigm for teaching and learning of evidence-based dentistry

Tan, L., Lai, S.M., Geres, N., Innes, N.P.T., Radford, J.R., Revie, G., et al.

Background: The Wikipedia Collaboration of Dental Schools (WCODS) is a student-led initiative that aims to publish high-quality scientific, evidencebased dental content on the Wikipedia online encyclopaedia by equipping its members to use research, critical appraisal and writing skills to create accurate content. In 2019, the Collaboration launched a standardised training programme developed by Wikimedia-trained committee members, academic dental school staff and the Cochrane Oral Health global community. Objective: To evaluate the effectiveness of this training programme in ensuring WCODS editors follow the processes underpinning evidence-based dentistry (EBD). Method: A cohort of dental students and staff (n=136) from six dental schools in the UK and Malaysia took part in a standardised and structured training programme at the annual WCODS training meeting. Participants’ abilities and their perceived levels of confidence in carrying out critical analysis of the literature were measured using pre- and post-training surveys, and competency assessments. Results: Participants’ skills in conducting literature searches, critical appraisal of the findings, and creating and editing a Wikipedia page improved after training. Conclusion: The training programme provided participants with the skill set and confidence to apply best practice to create and edit Wikipedia entries. This Collaboration intends to recruit more contributors to improve global oral health literacy using the free online Wikipedia encyclopaedia.

Quiz answers

Questions on page 298

1. This process is external cervical resorption (ECR), which usually occurs in the cervical aspect of a tooth as a result of damage to and/or deficiency of the periodontal ligament (PDL) and subepithelial cementum. It is a dynamic process with destructive (resorptive) and reparative phases. In this case the resorption has caused the tooth to undergo necrosis and apical periodontitis has developed.

2. The aetiology of ECR is unclear and poorly understood. Potential predisposing factors include but are not limited to: orthodontics; trauma; parafunction; malocclusion; extraction of neighbouring tooth; viral infections; eruption disorders; and, non-vital bleaching.

3. Patients are usually asymptomatic, and the lesions are usually advanced before the eventual invasion of the pulpal space causes symptoms of pulpitis or apical periodontitis. A pink spot may be visible but is rare, or a hard defect with associated perfuse bleeding can sometimes be felt clinically by probing. There is no classic radiographic appearance of ECR but these lesions are usually found incidentally on radiographic examination. Lesions can be either radiolucent or more radiodense depending on whether the ECR is in a resorptive or reparative phase. The root canal walls should be intact and traceable, which distinguishes this lesion from internal inflammatory resorption. 4. A CBCT is essential to be able to appropriately diagnose, classify and manage ECR. Treatment options include: 4 external repair, which may or may not include root canal treatment depending on the vitality of the pulp; 4 internal repair and root canal treatment; 4 intentional replantation; 4 if unrestorable/untreatable, then periodic review may be appropriate; and, 4 extraction if appropriate. In this case the tooth had become necrotic, so the option of internal repair and root canal treatment was chosen (Figure 3).

Community Dental Health 2021; 38: 1-5.

FIGURE 3: Post-op peri-apical X-ray.

Bibliography

1. Heithersay, G.S. Invasive cervical resorption. Endod Topics 2004; 7 (1): 73-92. 2. Patel, S., Mavridou, A.M., Lambrechts, P., Saberi, N. External cervical resorption – part 1: histopathology, distribution and presentation. Int Endod J 2018; 51 (11): 1205-1223. 3. Patel, S., Foschi, F., Condon, R., Pimentel, T., Bhuva, B. External cervical resorption: part 2 – management. Int Endod J 2018; 51 (11): 1224-1238.