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.

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.

Traditionally, dentists have encouraged both patients at low risk and patients at high risk of developing dental disease to attend their dental practices for regular 6-month 'check-ups'. There is, however, little evidence available for either patients or dentists to use when deciding on the best dental recall interval (i.e. time between dental check-ups) for maintaining oral health. In this study, we wanted to find out, for adult patients who regularly attend the dentist, what interval of time between dental check-ups maintains optimum oral health and represents value for money. A total of 2372 adults who regularly attended 51 different dental practices across Scotland, Northern Ireland, England and Wales were involved. Patients aged 18 years or over who received all or part of their care as NHS patients were randomly allocated to groups to receive a check-up either every 6 months, at an individualised recall interval based on their own risk of oral disease (risk-based recall), or every 24 months (if considered at low risk by their dentist). The recruited adults completed questionnaires at their first trial appointment and then every year of the 4-year study. Their attendance at recall appointments was recorded and they received a clinical assessment taken by study staff at the end of their involvement at year 4. After 4 years, there was no evidence of a difference in the oral health of patients allocated to a 6-month or variable risk-based recall interval. For patients considered by their dentists to be suitable for a 24-month recall interval, there was no difference between those in the 24-month, 6-month or risk-based recall intervals. However, people greatly value and are willing to pay for frequent dental check-ups. The recall strategy that offers the best value for money to patients and the NHS, therefore, depends on what people and decision-makers wish to value within a health-care system.

Improving the Quality of Dentistry (IQuaD): a cluster factorial randomised controlled trial comparing the effectiveness and cost-benefit of oral hygiene advice and/or periodontal instrumentation with routine care for the prevention and management of periodontal disease in dentate adults attending dental primary care.

BACKGROUND: Periodontal disease is preventable but remains the most common oral disease worldwide, with major health and economic implications. Stakeholders lack reliable evidence of the relative clinical effectiveness and cost-effectiveness of different types of oral hygiene advice (OHA) and the optimal frequency of periodontal instrumentation (PI). OBJECTIVES: To test clinical effectiveness and assess the economic value of the following strategies: personalised OHA versus routine OHA, 12-monthly PI (scale and polish) compared with 6-monthly PI, and no PI compared with 6-monthly PI. DESIGN: Multicentre, pragmatic split-plot, randomised open trial with a cluster factorial design and blinded outcome evaluation with 3 years' follow-up and a within-trial cost-benefit analysis. NHS and participant costs were combined with benefits [willingness to pay (WTP)] estimated from a discrete choice experiment (DCE). SETTING: UK dental practices. PARTICIPANTS: Adult dentate NHS patients, regular attenders, with Basic Periodontal Examination (BPE) scores of 0, 1, 2 or 3. INTERVENTION: Practices were randomised to provide routine or personalised OHA. Within each practice, participants were randomised to the following groups: no PI, 12-monthly PI or 6-monthly PI (current practice). MAIN OUTCOME MEASURES: Clinical - gingival inflammation/bleeding on probing at the gingival margin (3 years). Patient - oral hygiene self-efficacy (3 years). Economic - net benefits (mean WTP minus mean costs). RESULTS: A total of 63 dental practices and 1877 participants were recruited. The mean number of teeth and percentage of bleeding sites was 24 and 33%, respectively. Two-thirds of participants had BPE scores of ≤ 2. Under intention-to-treat analysis, there was no evidence of a difference in gingival inflammation/bleeding between the 6-monthly PI group and the no-PI group [difference 0.87%, 95% confidence interval (CI) -1.6% to 3.3%; p = 0.481] or between the 6-monthly PI group and the 12-monthly PI group (difference 0.11%, 95% CI -2.3% to 2.5%; p = 0.929). There was also no evidence of a difference between personalised and routine OHA (difference -2.5%, 95% CI -8.3% to 3.3%; p = 0.393). There was no evidence of a difference in self-efficacy between the 6-monthly PI group and the no-PI group (difference -0.028, 95% CI -0.119 to 0.063; p = 0.543) and no evidence of a clinically important difference between the 6-monthly PI group and the 12-monthly PI group (difference -0.097, 95% CI -0.188 to -0.006; p = 0.037). Compared with standard care, no PI with personalised OHA had the greatest cost savings: NHS perspective -£15 (95% CI -£34 to £4) and participant perspective -£64 (95% CI -£112 to -£16). The DCE shows that the general population value these services greatly. Personalised OHA with 6-monthly PI had the greatest incremental net benefit [£48 (95% CI £22 to £74)]. Sensitivity analyses did not change conclusions. LIMITATIONS: Being a pragmatic trial, we did not deny PIs to the no-PI group; there was clear separation in the mean number of PIs between groups. CONCLUSIONS: There was no additional benefit from scheduling 6-monthly or 12-monthly PIs over not providing this treatment unless desired or recommended, and no difference between OHA delivery for gingival inflammation/bleeding and patient-centred outcomes. However, participants valued, and were willing to pay for, both interventions, with greater financial value placed on PI than on OHA. FUTURE WORK: Assess the clinical effectiveness and cost-effectiveness of providing multifaceted periodontal care packages in primary dental care for those with periodontitis. TRIAL REGISTRATION: Current Controlled Trials ISRCTN56465715. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 38. See the NIHR Journals Library website for further project information.

The catalytic subunit of the system L1 amino acid transporter (slc7a5) facilitates nutrient signalling in mouse skeletal muscle.

The System L1-type amino acid transporter mediates transport of large neutral amino acids (LNAA) in many mammalian cell-types. LNAA such as leucine are required for full activation of the mTOR-S6K signalling pathway promoting protein synthesis and cell growth. The SLC7A5 (LAT1) catalytic subunit of high-affinity System L1 functions as a glycoprotein-associated heterodimer with the multifunctional protein SLC3A2 (CD98). We generated a floxed Slc7a5 mouse strain which, when crossed with mice expressing Cre driven by a global promoter, produced Slc7a5 heterozygous knockout (Slc7a5+/-) animals with no overt phenotype, although homozygous global knockout of Slc7a5 was embryonically lethal. Muscle-specific (MCK Cre-mediated) Slc7a5 knockout (MS-Slc7a5-KO) mice were used to study the role of intracellular LNAA delivery by the SLC7A5 transporter for mTOR-S6K pathway activation in skeletal muscle. Activation of muscle mTOR-S6K (Thr389 phosphorylation) in vivo by intraperitoneal leucine injection was blunted in homozygous MS-Slc7a5-KO mice relative to wild-type animals. Dietary intake and growth rate were similar for MS-Slc7a5-KO mice and wild-type littermates fed for 10 weeks (to age 120 days) with diets containing 10%, 20% or 30% of protein. In MS-Slc7a5-KO mice, Leu and Ile concentrations in gastrocnemius muscle were reduced by ∼40% as dietary protein content was reduced from 30 to 10%. These changes were associated with >50% decrease in S6K Thr389 phosphorylation in muscles from MS-Slc7a5-KO mice, indicating reduced mTOR-S6K pathway activation, despite no significant differences in lean tissue mass between groups on the same diet. MS-Slc7a5-KO mice on 30% protein diet exhibited mild insulin resistance (e.g. reduced glucose clearance, larger gonadal adipose depots) relative to control animals. Thus, SLC7A5 modulates LNAA-dependent muscle mTOR-S6K signalling in mice, although it appears non-essential (or is sufficiently compensated by e.g. SLC7A8 (LAT2)) for maintenance of normal muscle mass.

IQuaD dental trial; improving the quality of dentistry: a multicentre randomised controlled trial comparing oral hygiene advice and periodontal instrumentation for the prevention and management of periodontal disease in dentate adults attending dental primary care.

BACKGROUND: Periodontal disease is the most common oral disease affecting adults, and although it is largely preventable it remains the major cause of poor oral health worldwide. Accumulation of microbial dental plaque is the primary aetiological factor for both periodontal disease and caries. Effective self-care (tooth brushing and interdental aids) for plaque control and removal of risk factors such as calculus, which can only be removed by periodontal instrumentation (PI), are considered necessary to prevent and treat periodontal disease thereby maintaining periodontal health. Despite evidence of an association between sustained, good oral hygiene and a low incidence of periodontal disease and caries in adults there is a lack of strong and reliable evidence to inform clinicians of the relative effectiveness (if any) of different types of Oral Hygiene Advice (OHA). The evidence to inform clinicians of the effectiveness and optimal frequency of PI is also mixed. There is therefore an urgent need to assess the relative effectiveness of OHA and PI in a robust, sufficiently powered randomised controlled trial (RCT) in primary dental care. METHODS/DESIGN: This is a 5 year multi-centre, randomised, open trial with blinded outcome evaluation based in dental primary care in Scotland and the North East of England. Practitioners will recruit 1860 adult patients, with periodontal health, gingivitis or moderate periodontitis (Basic Periodontal Examination Score 0-3). Dental practices will be cluster randomised to provide routine OHA or Personalised OHA. To test the effects of PI each individual patient participant will be randomised to one of three groups: no PI, 6 monthly PI (current practice), or 12 monthly PI.Baseline measures and outcome data (during a three year follow-up) will be assessed through clinical examination, patient questionnaires and NHS databases.The primary outcome measures at 3 year follow up are gingival inflammation/bleeding on probing at the gingival margin; oral hygiene self-efficacy and net benefits. DISCUSSION: IQuaD will provide evidence for the most clinically-effective and cost-effective approach to managing periodontal disease in dentate adults in Primary Care. This will support general dental practitioners and patients in treatment decision making. TRIAL REGISTRATION: Protocol ID: ISRCTN56465715.

Iodothyronine Interactions with the System L1 Amino Acid Exchanger in 3T3-L1 Adipocytes.

Thyroid hormones enter isolated white adipocytes largely by a System L1-type amino acid transporter en route to exerting genomic actions. Differentiated 3T3-L1 mouse adipocytes in culture express mRNA for LAT1 (the catalytic subunit of high-affinity System L1). L-[(125)I]-T(3) uptake into 3T3-L1 adipocytes included a substantial saturable component inhibited by leucine. L-[(3)H]phenylalanine uptake into 3T3-L1 cells was saturable (K(m) of 31 µM), competitively inhibited by T(3) (K(i) of 1.2 µM) and blocked by leucine, BCH, and rT(3) as expected for substrate interactions of System L1. Efflux of preloaded L-[(3)H]phenylalanine from 3T3-L1 adipocytes was trans stimulated by external leucine, demonstrating the obligatory exchange mechanism of System L1 transport. T(3) (10 µM) did not significantly trans stimulate L-[(3)H]phenylalanine efflux, but did competitively inhibit the trans stimulatory effect of 10 µM leucine. The results highlight strong competitive interactions between iodothyronines (T(3), rT(3)) and amino acids for transport by System L1 in adipocytes, which may impact cellular iodothyronine exchanges during altered states of protein nutrition.