INTERVAL (investigation of NICE technologies for enabling risk-variable-adjusted-length) dental recalls trial: a multicentre randomised controlled trial investigating the best dental recall interval for optimum, cost-effective maintenance of oral health in dentate adults attending dental primary care

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.

Have you had bleeding from your gums? Self-report to identify giNGival inflammation (The SING diagnostic accuracy and diagnostic model development study)

AIM

To assess the diagnostic performance of self-reported oral health questions and develop a diagnostic model with additional risk factors to predict clinical gingival inflammation in systemically healthy adults in the United Kingdom.

METHODS

Gingival inflammation was measured by trained staff and defined as bleeding on probing (present if bleeding sites ≥ 30%). Sensitivity and specificity of self-reported questions were calculated; a diagnostic model to predict gingival inflammation was developed and its performance (calibration and discrimination) assessed.

RESULTS

We included 2853 participants. Self-reported questions about bleeding gums had the best performance: the highest sensitivity was 0.73 (95% CI 0.70, 0.75) for a Likert item and the highest specificity 0.89 (95% CI 0.87, 0.90) for a binary question. The final diagnostic model included self-reported bleeding, oral health behaviour, smoking status, previous scale and polish received. Its area under the curve was 0.65 (95% CI 0.63-0.67).

CONCLUSION

This is the largest assessment of diagnostic performance of self-reported oral health questions and the first diagnostic model developed to diagnose gingival inflammation. A self-reported bleeding question or our model could be used to rule in gingival inflammation since they showed good sensitivity, but are limited in identifying healthy individuals and should be externally validated.

Examining the effectiveness of different dental recall strategies on maintenance of optimum oral health: the INTERVAL dental recalls randomised controlled trial

Objective To compare the clinical effectiveness of different frequencies of dental recall over a four-year period.Design A multi-centre, parallel-group, randomised controlled trial with blinded clinical outcome assessment. Participants were randomised to receive a dental check-up at six-monthly, 24-monthly or risk-based recall intervals. A two-strata trial design was used, with participants randomised within the 24-month stratum if the recruiting dentist considered them clinically suitable. Participants ineligible for 24-month recall were randomised to a risk-based or six-month recall interval.Setting UK primary dental care.Participants Practices providing NHS care and adults who had received regular dental check-ups.Main outcome measures The percentage of sites with gingival bleeding on probing, oral health-related quality of life (OHRQoL), cost-effectiveness.Results In total, 2,372 participants were recruited from 51 dental practices. Of those, 648 were eligible for the 24-month recall stratum and 1,724 participants were ineligible. There was no evidence of a significant difference in the mean percentage of sites with gingival bleeding on probing between intervention arms in any comparison. For those eligible for 24-month recall stratum: the 24-month versus six-month group had an adjusted mean difference of -0.91%, 95% CI (-5.02%, 3.20%); the 24-month group versus risk-based group had an adjusted mean difference of 0.07%, 95% CI (-3.99%, 4.12%). For the overall sample, the risk-based versus six-month adjusted mean difference was 0.78%, 95% CI (-1.17%, 2.72%). There was no evidence of a difference in OHRQoL (0-56 scale, higher score for poorer OHRQoL) between intervention arms in any comparison. For the overall sample, the risk-based versus six-month effect size was -0.35, 95% CI (-1.02, 0.32). There was no evidence of a clinically meaningful difference between the groups in any comparison in either eligibility stratum for any of the secondary clinical or patient-reported outcomes.Conclusion Over a four-year period, we found no evidence of a difference in oral health for participants allocated to a six-month or a risk-based recall interval, nor between a 24-month, six-month or risk-based recall interval for participants eligible for a 24-month recall. However, patients greatly value and are willing to pay for frequent dental check-ups.

Dental therapists compared with general dental practitioners for undertaking check-ups in low-risk patients: pilot RCT with realist evaluation

Background

Many dental ‘check-ups’ in the NHS result in no further treatment. The patient is examined by a dentist and returned to the recall list for a further check-up, commonly in 6 or 12 months’ time. As the oral health of regular dental attenders continues to improve, it is likely that an increasing number of these patients will be low risk and will require only a simple check-up in the future, with no further treatment. This care could be delivered by dental therapists. In 2013, the body responsible for regulating the dental profession, the General Dental Council, ruled that dental therapists could see patients directly and undertake check-ups and routine dental treatments (e.g. fillings). Using dental therapists to undertake check-ups on low-risk patients could help free resources to meet the future challenges for NHS dentistry.

Objectives

The objectives were to determine the most appropriate design for a definitive study, the most appropriate primary outcome measure and recruitment and retention rates, and the non-inferiority margin. We also undertook a realist-informed process evaluation and rehearsed the health economic data collection tool and analysis.

Design

A pilot randomised controlled trial over a 15-month period, with a realist-informed process evaluation. In parallel, we rehearsed the health economic evaluation and explored patients’ preferences to inform a preference elicitation exercise for a definitive study.

Setting

The setting was NHS dental practices in North West England.

Participants

A total of 217 low-risk patients in eight high-street dental practices participated.

Interventions

The current practice of using dentists to provide NHS dental check-ups (treatment as usual; the control arm) was compared with using dental therapists to provide NHS dental check-ups (the intervention arm).

Main outcome measure

The main outcome measure was difference in the proportion of sites with bleeding on probing among low-risk patients. We also recorded the number of ‘cross-over’ referrals between dentists and dental therapists.

Results

No differences were found in the health status of patients over the 15 months of the pilot trial, suggesting that non-inferiority is the most appropriate design. However, bleeding on probing suffered from ‘floor effects’ among low-risk patients, and recruitment rates were moderately low (39.7%), which suggests that an experimental design might not be the most appropriate. The theory areas that emerged from the realist-informed process evaluation were contractual, regulatory, institutional logistics, patients’ experience and logistics. The economic evaluation was rehearsed and estimates of cost-effectiveness made; potential attributes and levels that can form the basis of preference elicitation work in a definitive study were determined.

Limitations

The pilot was conducted over a 15-month period only, and bleeding on probing appeared to have floor effects. The number of participating dental practices was a limitation and the recruitment rate was moderate.

Conclusions

Non-inferiority, floor effects and moderate recruitment rates suggest that a randomised controlled trial might not be the best evaluative design for a definitive study in this population. The process evaluation identified multiple barriers to the use of dental therapists in ‘high-street’ practices and added real value.

Future work

Quasi-experimental designs may offer more promise for a definitive study alongside further realist evaluation.

Trial registration

Current Controlled Trials ISRCTN70032696.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 9, No. 3. See the NIHR Journals Library website for further project information.

Risk-based, 6-monthly and 24-monthly dental check-ups for adults: the INTERVAL three-arm RCT

BACKGROUND

Traditionally, patients are encouraged to attend dental recall appointments at regular 6-month intervals, irrespective of their risk of developing dental disease. Stakeholders lack evidence of the relative effectiveness and cost-effectiveness of different recall strategies and the optimal recall interval for maintenance of oral health.

OBJECTIVES

To test effectiveness and assess the cost-benefit of different dental recall intervals over a 4-year period.

DESIGN

Multicentre, parallel-group, randomised controlled trial with blinded clinical outcome assessment at 4 years and a within-trial cost-benefit analysis. NHS and participant perspective costs were combined with benefits estimated from a general population discrete choice experiment. A two-stratum trial design was used, with participants randomised to the 24-month interval if the recruiting dentist considered them clinically suitable. Participants ineligible for 24-month recall were randomised to a risk-based or 6-month recall interval.

SETTING

UK primary care dental practices.

PARTICIPANTS

Adult, dentate, NHS patients who had visited their dentist in the previous 2 years.

INTERVENTIONS

Participants were randomised to attend for a dental check-up at one of three dental recall intervals: 6-month, risk-based or 24-month recall.

MAIN OUTCOMES

Clinical - gingival bleeding on probing; patient - oral health-related quality of life; economic - three analysis frameworks: (1) incremental cost per quality-adjusted life-year gained, (2) incremental net (societal) benefit and (3) incremental net (dental health) benefit.

RESULTS

A total of 2372 participants were recruited from 51 dental practices; 648 participants were eligible for the 24-month recall stratum and 1724 participants were ineligible. There was no evidence of a significant difference in the mean percentage of sites with gingival bleeding between intervention arms in any comparison. For the eligible for 24-month recall stratum: the 24-month (n = 138) versus 6-month group (n = 135) had an adjusted mean difference of -0.91 (95% confidence interval -5.02 to 3.20); the risk-based (n = 143) versus 6-month group had an adjusted mean difference of -0.98 (95% confidence interval -5.05 to 3.09); the 24-month versus risk-based group had an adjusted mean difference of 0.07 (95% confidence interval -3.99 to 4.12). For the overall sample, the risk-based (n = 749) versus 6-month (n = 737) adjusted mean difference was 0.78 (95% confidence interval -1.17 to 2.72). There was no evidence of a difference in oral health-related quality of life between intervention arms in any comparison. For the economic evaluation, under framework 1 (cost per quality-adjusted life-year) the results were highly uncertain, and it was not possible to identify the optimal recall strategy. Under framework 2 (net societal benefit), 6-month recalls were the most efficient strategy with a probability of positive net benefit ranging from 78% to 100% across the eligible and combined strata, with findings driven by the high value placed on more frequent recall services in the discrete choice experiment. Under framework 3 (net dental health benefit), 24-month recalls were the most likely strategy to deliver positive net (dental health) benefit among those eligible for 24-month recall, with a probability of positive net benefit ranging from 65% to 99%. For the combined group, the optimal strategy was less clear. Risk-based recalls were more likely to be the most efficient recall strategy in scenarios where the costing perspective was widened to include participant-incurred costs, and in the Scottish subgroup.

LIMITATIONS

Information regarding factors considered by dentists to inform the risk-based interval and the interaction with patients to determine risk and agree the interval were not collected.

CONCLUSIONS

Over a 4-year period, we found no evidence of a difference in oral health for participants allocated to a 6-month or a risk-based recall interval, nor between a 24-month, 6-month or risk-based recall interval for participants eligible for a 24-month recall. However, people greatly value and are willing to pay for frequent dental check-ups; therefore, the most efficient recall strategy depends on the scope of the cost and benefit valuation that decision-makers wish to consider.

FUTURE WORK

Assessment of the impact of risk assessment tools in informing risk-based interval decision-making and techniques for communicating a variable recall interval to patients.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN95933794.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme [project numbers 06/35/05 (Phase I) and 06/35/99 (Phase II)] and will be published in full in Health Technology Assessment; Vol. 24, No. 60. See the NIHR Journals Library website for further project information.

Developing a Mobile App (iGAM) to Promote Gingival Health by Professional Monitoring of Dental Selfies: User-Centered Design Approach

BACKGROUND

Dental visits are unpleasant; sometimes, patients only seek treatment when they are in intolerable pain. Recently, the novel coronavirus (COVID-19) pandemic has highlighted the need for remote communication when patients and dentists cannot meet in person. Gingivitis is very common and characterized by red, swollen, bleeding gums. Gingivitis heals within 10 days of professional care and with daily, thorough oral hygiene practices. If left untreated, however, its progress may lead to teeth becoming mobile or lost. Of the many medical apps currently available, none monitor gingivitis.

OBJECTIVE

This study aimed to present a characterization and development model of a mobile health (mHealth) app called iGAM, which focuses on periodontal health and improves the information flow between dentists and patients.

METHODS

A focus group discussed the potential of an app to monitor gingivitis, and 3 semistructured in-depth interviews were conducted on the use of apps for monitoring gum infections. We used a qualitative design process based on the Agile approach, which incorporated the following 5 steps: (1) user story, (2) use cases, (3) functional requirements, (4) nonfunctional requirements, and (5) Agile software development cycles. In a pilot study with 18 participants aged 18-45 years and with different levels of health literacy, participants were given a toothbrush, toothpaste, mouthwash, toothpicks, and dental floss. After installing iGAM, they were asked to photograph their gums weekly for 4 weeks.

RESULTS

All participants in the focus group believed in the potential of a mobile app to monitor gingivitis and reduce its severity. Concerns about security and privacy issues were discussed. From the interviews, 2 themes were derived: (1) "what's in it for me?" and (2) the need for a take-home message. The 5 cycles of development highlighted the importance of communication between dentists, app developers, and the pilot group. Qualitative analysis of the data from the pilot study showed difficulty with: (1) the camera, which was alleviated with the provision of mouth openers, and (2) the operation of the phone, which was alleviated by changing the app to be fully automated, with a weekly reminder and an instructions document. Final interviews showed satisfaction.

CONCLUSIONS

iGAM is the first mHealth app for monitoring gingivitis using self-photography. iGAM facilitates the information flow between dentists and patients between checkups and may be useful when face-to-face consultations are not possible (such as during the COVID-19 pandemic).

Oral health indices predict individualised recall interval

Objectives

The individualised recall interval (IRI) is part of the oral health examination. This observational, register‐based study aimed to explore how oral health indices DMFT (decayed, missing, filled teeth), DT (decayed teeth), CPI (Community Periodontal Index, maximum value of individual was used) and number of teeth are associated with IRI for adults.

Methods

Oral health examination includes an assessment of all oral tissues, diagnosis, a treatment plan and assessment and a determination of the interval before the next assessment. It is called the IRI. This cross‐sectional study population included 42,533 adults (age range 18–89 years), who had visited for an oral health examination during 2009, provided by the Helsinki City Social Services and Health Care. The recall interval was categorised into an ordinal scale (0–12, 13–24, 25–36 and 37–60 months) and was modelled using a proportional odds model. ORs less than one indicated a shorter recall interval.

Results

Recall interval categories in the study population were 0–12 months (n = 4,569; 11%), 13–24 months (n = 23,732; 56%), 25–36 months (n = 12,049; 28%), and 37–60 months (n = 2,183; 5%). The results of statistical models clearly showed an association between the length of recall intervals and oral health indices. In all models, higher values of DMFT, DT and CPI indicated a shorter recall interval. The number of teeth were not so relevant. The association was not influenced when different combinations of other predictors (age, gender, socioeconomic status, chronic diseases) were included in the model. The severity of periodontitis predicted a short recall interval, for example, in the Model 1, CPI maximum value 4 was OR = 0.35 (95% confidence interval 0.31–0.40).

Conclusions

The oral health indices showed a clear association with the length of the IRI. Poor oral health reduced IRI. The indices provide information about the amount of oral health prevention required and are useful to health organisations.

Association between Subjective Well-Being and Frequent Dental Visits in the German Ageing Survey

The relationship between subjective well-being (SWB) and frequent attendance is understudied. This study used data from a large German sample of non-institutionalized individuals aged 40+ in 2014 (n = 7264). SWB was measured using the Satisfaction with Life Scale (SWLS) and the Positive and Negative Affect Schedule (PANAS). Number of self-reported dental visits in the past twelve months was used to measure the utilization frequency of dental services. Individuals with at least four dental visits in the preceding year (highest decile) were defined as frequent dental visits. Robustness checks were performed using alternative cut-offs to define frequent dental visits. Multiple logistic regressions showed that frequent dental visits (highest decile) were associated with less satisfaction with life [OR: 0.89, 95%-CI: 0.80–0.99] and higher negative affect [OR: 1.41, 95%-CI: 1.22–1.64], whereas it was not significantly associated with positive affect. Both associations depended on the cut-off chosen to define frequent dental visits. The present study highlights the association between SWB (particularly negative affect and low life satisfaction) and frequent dental visits. Further studies evaluating patients’ motivation for high dental service use are necessary to check the robustness of our findings.

Implementation of altered provider incentives for a more individual-risk-based assignment of dental recall intervals: evidence from a health systems reform in Denmark

Equipping health systems with suitable incentives for efficient resource allocation remains a major health policy challenge. This study examines the impacts of 2015 regulatory changes in Danish dental care which aimed at effectuating a transition from six-to-twelve-monthly dental recall intervals, for every patient, towards a model where patients with higher need receive dental recalls systematically more frequently than patients with lower need. Exploiting administrative data from the years 2012-2016 from the Danish National Health Insurance database containing 72,155,539 treatment claims for 3,759,721 unique patients, we estimated a series of interrupted time-series regression models with patient-level fixed-effects. In comparison to the pre-reform period, the proportion of patients with recall intervals of up to 6 months was by 1.2%-points larger post-implementation; that of patients with 6-12-monthly recalls increased by 0.7%-points; that of patients with more than 12-monthly dental recalls decreased by 1.9%-points. The composition of care shifted more substantially: the proportion of treatment sessions including preventive care increased by 31.5%-points (95%-CI: 31.4;31.6); that of sessions including scaling increased by 24.1%-points (24.0;24.2); that of sessions including diagnostics decreased by 34.5%-points (34.4;34.6). These findings suggest that dental care providers may have responded differently to regulatory changes than intended by the health policy.

Three behavior change theory-informed randomized studies within a trial to improve response rates to trial postal questionnaires

OBJECTIVES

Our aim was to design and evaluate a novel behavior change approach to increase response rates to an annual postal questionnaire in three randomized studies within a trial (SWAT) and replicate the most promising SWAT.

STUDY DESIGN AND SETTING

SWAT1 tested a trial logo sticker on questionnaire envelopes vs. no sticker; SWAT2 tested a theoretically informed letter sent with the questionnaire vs. a standard letter; SWAT3 tested a theoretically informed newsletter sent before the questionnaire vs. no newsletter. The SWATs were conducted within a large dental trial (N = 1,877 adults), and SWAT2 replicated in a different trial in a similar setting (N = 2,372).

RESULTS

SWAT1 improved response rates by 1.4%, 95% confidence interval (CI) (-7.2%, 10.0%). SWAT2 improved response rates by 7.0%, 95% CI (1.7%, 12.3%). SWAT3 improved response rates by 0.8%, 95% CI (-5.1%, 6.7%). Replication of SWAT2 as the most promising SWAT showed improvement in response rates of 1.0%, 95% CI (-3.2%, 5.3%). Pooled results from SWAT2 showed an overall improvement in response rates of 3.4%, 95% CI (0.1%, 6.7%).

CONCLUSION

A theory-based behavioral approach to design interventions to improve trial response rates showed small but meaningful improvements. The approach presented here can be easily implemented and adapted to address other identified barriers to trial retention.

Impact of changing provider remuneration on NHS general dental practitioner services in Northern Ireland: a mixed-methods study

Background

Policy-makers wanted to reform the NHS dental contract in Northern Ireland to contain costs, secure access and incentivise prevention and quality. A pilot project was undertaken to remunerate general dental practitioners using a capitation-based payment system rather than the existing fee-for-service system.

Objective

To investigate the impact of this change in remuneration.

Design

Mixed-methods design using a difference-in-difference evaluation of clinical activity levels, a questionnaire of patient-rated outcomes and qualitative assessment of general dental practitioners’ and patients’ views.

Setting

NHS dental practices in Northern Ireland.

Participants

General dental practitioners and patients in 11 intervention practices and 18 control practices.

Interventions

Change from fee for service to a capitation-based system for 1 year and then reversion back to fee for service.

Main outcome measures

Access to care, activity levels, service mix and financial impact, and patient-rated outcomes of care.

Results

The difference-in-difference analyses showed significant and rapid changes in the patterns of care provided by general dental practitioners to patients (compared with the control practices) when they moved from a fee-for-service system to a capitation-based remuneration system. The number of registered patients in the intervention practices compared with the control practices showed a small but statistically significant increase during the capitation period (p < 0.01), but this difference was small. There were statistically significant reductions in the volume of activity across all treatments in the intervention practices during the capitation period, compared with the control practices. This produced a concomitant reduction in patient charge revenue of £2403 per practice per month (p < 0.05). All outcome measures rapidly returned to baseline levels following reversion from the capitation-based system back to a fee-for-service system. The analysis of the questionnaires suggests that patients did not appear to notice very much change. Qualitative interviews showed variation in general dental practitioners’ behaviour in response to the intervention and how they managed the tension between professional ethics and maximising the profits of their business. Behaviours were also heavily influenced by local context. Practice principals preferred the capitation model as it freed up time and provided opportunities for private work, whereas capitation payments were seen by some principals as a ‘retainer fee’ for continuing to provide NHS care. Non-equity-owning associates perceived the capitation model as a financial risk.

Limitations

The active NHS pilot period was only 1 year, which may have limited the scope for meaningful change. The number of sites was restricted by the financial budget for the NHS pilot.

Conclusions

General dental practitioners respond rapidly and consistently to changes in remuneration, but differences were found in the extent of this change by practice and provider type. A move from a fee-for-service system to a capitation-based system had little impact on access but produced large reductions in clinical activity and patient charge income. Patients noticed little difference in the service that they received.

Future work

With changing population need and increasing financial pressure on the NHS, research is required on how to most efficiently meet the expectations of patients within an affordable cost envelope. Work is also needed to identify and evaluate interventions that can complement changes in remuneration to meet policy goals.

Trial registration

Current Controlled Trials ISRCTN29840057.

Funding

This project was funded by the National Institute for Health Research (NIHR) Health Services and Delivery Research programme and will be published in full in Health Services and Delivery Research; Vol. 8, No. 6. See the NIHR Journals Library website for further project information.