Protocol for a Randomised controlled trial to Evaluate the effectiveness and cost benefit of prescribing high dose FLuoride toothpaste in preventing and treating dEntal Caries in high-risk older adulTs (reflect trial)

Undertaking Studies Within A Trial to evaluate recruitment and retention strategies for randomised controlled trials: lessons learnt from the PROMETHEUS research programme

Background

Randomised controlled trials ('trials') are susceptible to poor participant recruitment and retention. Studies Within A Trial are the strongest methods for testing the effectiveness of strategies to improve recruitment and retention. However, relatively few of these have been conducted.

Objectives

PROMoting THE Use of Studies Within A Trial aimed to facilitate at least 25 Studies Within A Trial evaluating recruitment or retention strategies. We share our experience of delivering the PROMoting THE Use of Studies Within A Trial programme, and the lessons learnt for undertaking randomised Studies Within A Trial.

Design

A network of 10 Clinical Trials Units and 1 primary care research centre committed to conducting randomised controlled Studies Within A Trial of recruitment and/or retention strategies was established. Promising recruitment and retention strategies were identified from various sources including Cochrane systematic reviews, the Study Within A Trial Repository, and existing prioritisation exercises, which were reviewed by patient and public members to create an initial priority list of seven recruitment and eight retention interventions. Host trial teams could apply for funding and receive support from the PROMoting THE Use of Studies Within A Trial team to undertake Studies Within A Trial. We also tested the feasibility of undertaking co-ordinated Studies Within A Trial, across multiple host trials simultaneously.

Setting

Clinical trials unit-based trials recruiting or following up participants in any setting in the United Kingdom were eligible.

Participants

Clinical trials unit-based teams undertaking trials in any clinical context in the United Kingdom.

Interventions

Funding of up to £5000 and support from the PROMoting THE Use of Studies Within A Trial team to design, implement and report Studies Within A Trial.

Main outcome measures

Number of host trials funded.

Results

Forty-two Studies Within A Trial were funded (31 host trials), across 12 Clinical Trials Units. The mean cost of a Study Within A Trial was £3535. Twelve Studies Within A Trial tested the same strategy across multiple host trials using a co-ordinated Study Within A Trial design, and four used a factorial design. Two recruitment and five retention strategies were evaluated in more than one host trial. PROMoting THE Use of Studies Within A Trial will add 18% more Studies Within A Trial to the Cochrane systematic review of recruitment strategies, and 79% more Studies Within A Trial to the Cochrane review of retention strategies. For retention, we found that pre-notifying participants by card, letter or e-mail before sending questionnaires was effective, as was the use of pens, and sending personalised text messages to improve questionnaire response. We highlight key lessons learnt to guide others planning Studies Within A Trial, including involving patient and public involvement partners; prioritising and selecting strategies to evaluate and elements to consider when designing a Study Within A Trial; obtaining governance approvals; implementing Studies Within A Trial, including individual and co-ordinated Studies Within A Trials; and reporting Study Within A Trials.

Limitations

The COVID-19 pandemic negatively impacted five Studies Within A Trial, being either delayed (n = 2) or prematurely terminated (n = 3).

Conclusions

PROMoting THE Use of Studies Within A Trial significantly increased the evidence base for recruitment and retention strategies. When provided with both funding and practical support, host trial teams successfully implemented Studies Within A Trial.

Future work

Future research should identify and target gaps in the evidence base, including widening Study Within A Trial uptake, undertaking more complex Studies Within A Trial and translating Study Within A Trial evidence into practice.

Study registration

All Studies Within A Trial in the PROMoting THE Use of Studies Within A Trial programme had to be registered with the Northern Ireland Network for Trials Methodology Research Study Within A Trial Repository.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health Technology Assessment programme (NIHR award ref: 13/55/80) and is published in full in Health Technology Assessment; Vol. 28, No. 2. See the NIHR Funding and Awards website for further award information.

Using re-randomisation designs to increase the efficiency and applicability of retention studies within trials: a case study

BACKGROUND

Poor retention in randomised trials can lead to serious consequences to their validity. Studies within trials (SWATs) are used to identify the most effective interventions to increase retention. Many interventions could be applied at any follow-up time point, but SWATs commonly assess interventions at a single time point, which can reduce efficiency.

METHODS

The re-randomisation design allows participants to be re-enrolled and re-randomised whenever a new retention opportunity occurs (i.e. a new follow-up time point where the intervention could be applied). The main advantages are as follows: (a) it allows the estimation of an average effect across time points, thus increasing generalisability; (b) it can be more efficient than a parallel arm trial due to increased sample size; and (c) it allows subgroup analyses to estimate effectiveness at different time points. We present a case study where the re-randomisation design is used in a SWAT.

RESULTS

In our case study, the host trial is a dental trial with two available follow-up points. The Sticker SWAT tests whether adding the trial logo's sticker to the questionnaire's envelope will result in a higher response rate compared with not adding the sticker. The primary outcome is the response rate to postal questionnaires. The re-randomisation design could double the available sample size compared to a parallel arm trial, resulting in the ability to detect an effect size around 28% smaller.

CONCLUSION

The re-randomisation design can increase the efficiency and generalisability of SWATs for trials with multiple follow-up time points.

Development of a Root Caries Prediction Model in a Population of Dental Attenders

Root caries prevalence is increasing as populations age and retain more of their natural dentition. However, there is generally no accepted practice to identify individuals at risk of disease. There is a need for the development of a root caries prediction model to support clinicians to guide targeted prevention strategies. The aim of this study was to develop a prediction model for root caries in a population of regular dental attenders. Clinical and patient-reported predictors were collected at baseline by routine clinical examination and patient questionnaires. Clinical examinations were conducted at the 4-year timepoint by trained outcome assessors blind to baseline data to record root caries data at two thresholds - root caries present on any teeth (RC > 0) and root caries present on three or more teeth (RC ≥ 3). Multiple logistic regression analyses were performed with the number of participants with root caries at each outcome threshold utilized as the outcome and baseline predictors as the candidate predictors. An automatic backwards elimination process was conducted to select predictors for the final model at each threshold. The sensitivity, specificity, and c-statistic of each model's performance was assessed. A total of 1,432 patient participants were included within this prediction model, with 324 (22.6%) presenting with at least one root caries lesion, and 97 (6.8%) with lesions on three or more teeth. The final prediction model at the RC >0 threshold included increasing age, having ≥9 restored teeth at baseline, smoking, lack of knowledge of spitting toothpaste without rinsing following toothbrushing, decreasing dental anxiety, and worsening OHRQoL. The model sensitivity was 71.4%, specificity 69.5%, and c-statistic 0.79 (95% CI: 0.76, 0.81). The predictors included in the final prediction model at the RC ≥ 3 threshold included increasing age, smoking, and lack of knowledge of spitting toothpaste without rinsing following toothbrushing. The model sensitivity was 76.5%, specificity 73.6%, and c-statistic 0.81 (95% CI: 0.77, 0.86). To the authors' knowledge, this is the largest published root caries prediction model, with statistics indicating good model fit and providing confidence in its robustness. The performance of the risk model indicates that adults at risk of developing root caries can be accurately identified, with superior performance in the identification of adults at risk of multiple lesions.

Fluoride Intake and Salivary Fluoride Retention after Using High-Fluoride Toothpaste Followed by Post-Brushing Water Rinsing and Conventional (1400-1450 ppm) Fluoride Toothpastes Used without Rinsing

This study aimed to compare the fluoride intake and salivary fluoride levels after brushing with conventional (1400-1450 ppm) fluoride toothpaste containing different fluoride agents: amine fluoride (AmF), sodium fluoride (NaF), sodium monofluorophosphate (SMFP), potassium fluoride (KF), and a high-fluoride (5000 ppm) toothpaste containing NaF. Fourteen volunteers took part in the study. They were instructed to brush and spit without rinsing after using conventional toothpaste or brush and rinse with water after using a high-fluoride toothpaste. Fluoride concentrations were determined using ion-selective fluoride (09-37 type) in the saliva samples before and after procedures. Fluoride intake was estimated based on fluoride recovered after brushing. Additionally, the amount of fluoride present in the oral fluids and lost during the rapid clearance phase after toothbrushing was calculated based on salivary fluoride levels and saliva flow immediately after brushing. Salivary fluoride after using high-fluoride toothpaste was significantly higher than those observed after conventional products. Two hours after brushing, salivary fluoride concentrations did not differ significantly from baseline values (p > 0.05) unless a high-fluoride product was used. Results indicate that by refraining from rinsing after brushing with conventional toothpaste, we cannot obtain fluoride retention in saliva as with high-fluoride toothpaste. Fluoride ingestion was higher after using a high-fluoride product.

Diagnostic accuracy, available treatment, and diagnostic methods of dental caries in practice: a meta-analysis

Background

Diagnosis of dental caries and identification of patients with dental caries is the biggest challenge in dentistry. For this diagnostic accuracy, several methods are studied. The present study attempts to re-study the published data in the last 50 years, between 1960 and 2020.

Main body

Based on designed keywords, we made a thorough search of 4 different databases and found 3887 articles after removing the duplicate. The included database was PubMed, Ovid, Web of Science, and Cochrane library. On keen screening of the articles, we included 19 articles in the review. All the articles were analyzed based on the Cochrane risk assessment method. Maximum studies of up to 80% of caries management are based on children from 1 to 10 years of age. About 47% of articles were found based on reported use of drugs against dental caries, whereas 52.6% of articles were based on the behavioral and socio-demographic study of the mother and caretakers. We found that attentive parents and caretakers of the children can help in reducing the prevention of caries. Frese et al. (Sci Rep. 8(1):16991, 2018. 10.1038/s41598-018-34777-x), Liu et al. (PLoS ONE 8(11):e78723, 2013. 10.1371/journal.pone.0078723), and Innes et al. J Dent Res 99(1):36–43, 2020. 10.1177/0022034519888882) were the studied articles with high quality and low bias risk. These methods were based on the use of stannous fluoride for dental caries, the study of the effect of smoking on older adults, by checking the anxiety level of the participants.

Short conclusions

Tooth decay is a common condition in the general population and affects mostly children. The method with high accuracy and low risk can be recommended for routine treatment.

Unlocking the potential of NHS primary care dental datasets

Introduction Maximising the use of routinely collected health data for research is a key part of the UK Government's Industrial Strategy. Rich data are generated by NHS primary care dental services, but the extent of their use in research is unknown.Aims To profile the utility of the post-2006 NHS dental datasets for research, map how they have been used to date and develop recommendations to maximise their utility.Methods The content of and access to the four UK NHS dental datasets was collated using publicly available information and a free-text questionnaire, completed by the relevant data controllers. A scoping review was carried out to identify and map literature that has utilised NHS dental activity data.Results The contents of the UK NHS dental activity datasets are described, alongside how they may be accessed for research. Strengths and weaknesses of these datasets for research are highlighted. The scoping review identified 33 studies which had utilised NHS dental activity data since 2006. We classified 15 as public health practice, 11 as service evaluation and 7 as research.Conclusion In comparision to other NHS activity datasets, it appears that the UK dental datasets have been underutilised for research. We make 11 recommendations on how their utility for research may be increased.

Dietary Calcium Alleviates Fluorine-Induced Liver Injury in Rats by Mitochondrial Apoptosis Pathway

Excessive fluoride (F) exposure can lead to liver damage; moreover, recent studies found that the addition of appropriate calcium (Ca) can alleviate the symptom of skeletal fluorosis. However, whether Ca can relieve F-induced liver damage through the mitochondrial apoptosis pathway has not been reported yet. Therefore, we assessed the liver morphology, serum transaminase content, liver oxidative stress-related enzymes, and apoptosis-related gene and protein expression in Sprague Dawley (SD) rats treated with 150 mg/L sodium fluoride (NaF) and different concentrations of calcium carbonate (CaCO₃) for 120 days. Our results showed that NaF brought out pathological changes in liver morphology, serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels increased, total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) content decreased, and malondialdehyde (MDA) content increased, suggesting that NaF caused hepatotoxicity and oxidative stress. In addition, the results of quantitative real-time PCR (qRT-PCR) and immunohistochemistry showed that NaF exposure upregulated the expression of Bcl-2-associated x protein (Bax), rho-related coiled-coil kinase 1 (ROCK1), cytochrome C (Cyto-C) mRNA and protein (P < 0.01), and downregulated B cell lymphoma 2 (Bcl-2) protein and mRNA (P < 0.01), indicating that excessive F exposure activated mitochondrial-mediated apoptosis in the liver. However, the addition of 1% CaCO₃ to the diet significantly increased the expression of anti-apoptotic gene Bcl-2 (P < 0.01), inhibited the activation of the mitochondrial apoptosis pathway, and reduced mitochondrial damage. In summary, supplementing 1% CaCO₃ in the diet can alleviate the NaF-induced liver cell damage through the mitochondrial apoptosis pathway.