Gut microbiome composition and functionality impact the responsiveness to a dairy-based product containing galacto-oligosaccharides for improving sleep quality in adults.

Sleep quality and duration can be impacted by diet, and has been linked to gut microbiota composition and function as the result of communication via the microbiota-gut-brain axis. As one strategy to improve sleep quality could be through the modulation of the gut microbiome, we assessed the effects of a dairy-based product containing whey protein, galacto-oligosaccharides, tryptophan, vitamins and minerals after a 3 weeks intervention on gut microbiota composition and (gut-brain related) functions on basis of 67 healthy subjects with moderate sleep disturbances. Associations of the gut microbiota with sleep quality and with response/non-response to the treatment were revealed by shotgun metagenomics sequencing of faecal DNA samples, and subsequent analyses of microbiota taxonomy and generic functionality. A database of manually curated Gut-Brain Modules (GBMs) was applied to analyse specific microbial functions/pathways that have the potential to interact with the brain. A moderate discriminating effect of the DP treatment on gut microbiota composition was revealed which could be mainly attributed to a decrease in Pseudomonas resinovorans, Flintibacter sp. KGM00164, Intestinimonas butyriciproducens, and Flavonifractor plautii. As interindividual variance in microbiota composition could have given rise to a heterogenous responsiveness of the subjects in the intervention group, we zoomed in on the differences between responders and non-responders. A significant difference in baseline microbiota composition between responders and non-responders was apparent, showing lower Bifidobacterium longum and Bifidobacterium adolescentis, and higher Faecalibacterium prausnitzii relative abundances in responders. The findings provide leads with respect to the effectiveness and potential underlying mechanisms of mode of action in sleep improvement that could support future nutritional interventions to aid sleep improvement.

Developing a national undergraduate medical education pain management and substance use disorder curriculum to address the opioid crisis: a program evaluation pilot study.

BACKGROUND: Pain and addiction are one of the most common reasons for adults to seek health care, yet educational programs focused on pain are often underrepresented in medical school curricula. In January 2021, the Association of Faculties of Medicine of Canada (AFMC) launched an online national, bilingual, competency-based curriculum for undergraduate medical (UGME) students in pain management and substance use in response to the opioid crisis and to bridge the content gaps in programs across Canada. The purpose of this study is to evaluate the pilot of this national curriculum. METHODS: UGME students, from across Canada, participated in the program evaluation by completing online pre- and post-program surveys that assessed the influence of the curriculum on participants' knowledge as well as the value, usability, and feasibility of this curriculum. RESULTS: Participants' perceived confidence in their new knowledge and in utilizing resources required to maintain their knowledge significantly increased (75% and 51% respectively). Their perceived knowledge that addressed the 72 learning objectives within the curriculum significantly increased from pre- to post-program. Over 90% of participants reported that the curriculum was valuable, feasible, and usable. The most frequently discussed program strengths were the clear and comprehensive content, interactive and well-organized design, and relevance of curriculum content for future clinical practice. The overall weakness of the curriculum included the length, repetition of content, the lack of clarity and relevance of the assessment questions, end-user technology issues, and French translation discrepancies. Participant's recommendations for improving the curriculum included streamlining content, addressing technology issues, and enhancing the clarity and relevance of assessment questions embedded within each of the modules. CONCLUSION: Participants agreed that an online pain management and substance use curriculum is a valuable, usable, and feasible learning opportunity. Given the severity of the opioid crisis in Canada, these online modules provide a curriculum that can be integrated into existing UGME programs or can provide self-directed learning.

Single-arm trials supporting the approval of anticancer medicinal products in the European Union: contextualization of trial results and observed clinical benefit.

BACKGROUND: Single-arm trials (SATs) can sometimes be used to support marketing authorization of anticancer medicinal products in the European Union. The level and durability of antitumor activity of the product as well as context are important aspects to determine the relevance of trial results. The aim of this study is to provide details on the contextualization of trial results and to evaluate the magnitude of benefit of medicinal products approved based on SATs. MATERIALS AND METHODS: We focused on anticancer medicinal products for solid tumors approved on the basis of SAT results (2012-2021). Data were retrieved from European public assessment reports and/or published literature. The benefit of these medicinal products was evaluated via the European Society for Medical Oncology (ESMO)-Magnitude of Clinical Benefit Scale (MCBS). RESULTS: Eighteen medicinal products were approved based on 21 SATs-few medicinal products were supported by >1 SAT. For the majority of clinical trials, a clinically relevant treatment effect was (pre)specified (71.4%) and most often an accompanying sample size calculation was provided. For 10 studies, each testing a different medicinal product, a justification for the threshold for a clinically relevant treatment effect could be identified. At least 12 out of 18 applications included information to facilitate the contextualization of trial results, including six supportive studies. Of the pivotal SATs analyzed (n = 21), three were assigned an ESMO-MCBS score of 4, which corresponds to 'substantial' benefit. CONCLUSIONS: The clinical relevance of the treatment effects shown by medicinal products for solid tumors tested in SATs is dependent on the effect size and context. To better facilitate regulatory decision making, prespecifying and motivating a clinically relevant effect and aligning the sample size to that effect is important. External controls may facilitate in the contextualization process, but the associated limitations must be addressed.

Creating a kidney organoid-vasculature interaction model using a novel organ-on-chip system.

Kidney organoids derived from human induced pluripotent stem cells (iPSCs) have proven to be a valuable tool to study kidney development and disease. However, the lack of vascularization of these organoids often leads to insufficient oxygen and nutrient supply. Vascularization has previously been achieved by implantation into animal models, however, the vasculature arises largely from animal host tissue. Our aim is to transition from an in vivo implantation model towards an in vitro model that fulfils the advantages of vascularization whilst being fully human-cell derived. Our chip system supported culturing of kidney organoids, which presented nephron structures. We also showed that organoids cultured on chip showed increased maturation of endothelial populations based on a colocalization analysis of endothelial markers. Moreover, we observed migration and proliferation of human umbilical vein endothelial cells (HUVECs) cultured in the channels of the chip inside the organoid tissue, where these HUVECs interconnected with endogenous endothelial cells and formed structures presenting an open lumen resembling vessels. Our results establish for the first-time vascularization of kidney organoids in HUVEC co-culture conditions using a microfluidic organ-on-chip. Our model therefore provides a useful insight into kidney organoid vascularization in vitro and presents a tool for further studies of kidney development and drug testing, both for research purposes and pre-clinical applications.

BIC extensions for order-constrained model selection.

The Schwarz or Bayesian information criterion (BIC) is one of the most widely used tools for model comparison in social science research. The BIC however is not suitable for evaluating models with order constraints on the parameters of interest. This paper explores two extensions of the BIC for evaluating order constrained models, one where a truncated unit information prior is used under the order-constrained model, and the other where a truncated local unit information prior is used. The first prior is centered around the maximum likelihood estimate and the latter prior is centered around a null value. Several analyses show that the order-constrained BIC based on the local unit information prior works better as an Occam's razor for evaluating order-constrained models and results in lower error probabilities. The methodology based on the local unit information prior is implemented in the R package 'BFpack' which allows researchers to easily apply the method for order-constrained model selection. The usefulness of the methodology is illustrated using data from the European Values Study.

The feasibility and effectiveness of a novel online mental health literacy course in supporting university student mental health: a pilot study.

BACKGROUND: There is a need for effective universal approaches to promote and support university student mental health that are scalable and sustainable. In this pilot study we assess the feasibility and acceptability of a fully-digitalized, comprehensive mental health literacy course co-created with and tailored to the needs of undergraduate students. We also explore preliminary associations with mental health and positive behaviour change. METHODS: An accredited online mental health literacy course was developed using state-of-the-art pedagogical principles and a reverse mentorship approach. The course was offered as an interdisciplinary undergraduate elective. Students completed an online survey before and after the 12-week course that collected demographic information and assessed mental health knowledge, emotional self-awareness, mental health, stigma, and health-related behaviors using validated measures. Dependent group t-tests were used to compare pre- and post-course levels of knowledge, mental health, sleep quality and substance use. Mental health outcomes of students who completed the course were compared to an age and sex-matched sample of students not enrolled in the course and who completed the same survey measures over the same academic year. Multivariable linear regression was used to examine the effect of course participation on outcomes at follow-up. RESULTS: The course had good uptake and was positively reviewed by participants. Specifically, students found the course engaging, relevant, and applicable, and agreed they would recommend it to their peers. Among course participants there was improvement in mental health knowledge (p < 0.001) and emotional self-awareness (p = 0.02) at course completion. Compared to the matched comparison group, taking the course was associated with reduced alcohol (ß = - 0.41, p = 0.01) and cannabis use (ß = - 0.35, p = 0.03), and improved sleep quality (ß = 1.56, p = 0.09) at the end of the term. CONCLUSIONS: Findings suggest that delivering mental health literacy as an online accredited course may be an acceptable and effective way of promoting university student mental health through improved knowledge, emotional self-awareness, and healthy lifestyle choices. As the course is expanded to larger and more diverse student cohorts we will be able to further examine the short and long-term effectiveness of the course in supporting student mental health and the underlying mechanisms.

Reasons for contacting the consultation service of a Dutch assault centre.

A telephone and e-mail helpline known as the Consultation Service, open to all the public, was launched at a Dutch Centre for Sexual Violence to deal with non-acute sexual violence. The aim of this study was to gain insight into case characteristics, reasons for contacting the Consultation Service and whether these reasons differed for victims, their relatives and professionals. Using a mixed methods design, the study included all consultations handled at the Consultation Service in 2018 and 2019. Descriptive statistics described quantitatively the case characteristics, the themes and differences between victims, relatives and professionals. The themes of the reasons for contact were established from the qualitative analysis, using the method of content analysis. Cases were characterised by complexity. Three themes emerged: case complexity, decision-making on care options and reporting to the police, which differed for victims, relatives and professionals. The differences in reasons for contacting the helpline imply that approaches should be adapted and fitted to different clients. Specialised care is needed to guide clients through cases that are challenging and often complex. There is a widespread lack of knowledge of options in addition to the complex multifaceted aspects to decision making about actions post-assault. Assault centres should implement a Consultation Service in which integrated care is offered not only to the victims, but also to their relatives and professionals.

Reporting after sexual violence: The influence of victim, assault and perpetrator characteristics.

Sexual violence is a worldwide public health concern. Care for victims has improved with the development of sexual assault centres, which have served to professionalise and tailor care and to get different services to improve collaboration. Nonetheless, reporting rates remain low, causing perpetrators to walk free without prosecution. We aimed to investigate, firstly, the influence of victim, perpetrator and assault characteristics on the reporting rate, and, secondly, the reasons why victims did not report to the police. Data of a Dutch sexual assault centre was used in this cross-sectional study. All victims who attended the centre between January 2016 and January 2019 were included. Logistic regression analysis was used to assess the relation of certain characteristics with reporting. Forty per cent of the victims reported to the police. Age and injuries were significantly related to reporting. Victims of 26 years or over were less likely to report than victims under 18 years old. Victims with objectified injuries reported to the police more often. Contrary to previous research, no relation between the perpetrator being well-known to the victim and a lower reporting rate was found. Victims mainly refrained from reporting as they experienced conflicting emotions, followed by their feeling discouraged by the police. Other reasons were fear of the perpetrator and defamation, wanting to move on with their life and wanting to spare the perpetrator. Our findings will serve to further optimise care for victims of sexual violence and increase reporting rates.

Survival of multiple-surface ART restorations using a zinc-reinforced glass-ionomer restorative after 2 years: A randomized triple-blind clinical trial.

OBJECTIVE: To investigate the effectiveness of a new zinc-reinforced glass-ionomer in comparison to a common high-viscous glass-ionomer cement (HVGIC) used in multiple-surface ART-prepared cavities. The hypothesis tested was that the cumulative survival percentage of the new HVGIC is higher than that of the common HVGIC over 2 years. METHODS: A randomized triple-blind parallel group clinical trial was used. A total of 218 participants, average age 15.4 years (SD=0.2), with an occluso-proximal carious lesion in a permanent (pre-) molar were included. Restorations using test (ChemFil Rock) and control (Fuji IX GP) restoratives were placed according to the ART method by four calibrated operators. Restorations were evaluated after one week (baseline), and at 6-, 12-, 18- and 24 months from replicas and coloured photographs according to the ART restoration assessment criteria by two independent evaluators. Restoration survival curves were estimated using the Kaplan-Meier method and difference between dependent and independent variables tested with a Wald (chi-square) test. RESULTS: There was a statistically significant difference in cumulative survival percentages between the two types of restorations at 2 years (P=0.02). A higher percentage of multiple-surface restorations of Fuji IX GP (95.4%) than ChemFil Rock (85.3%) survived. Gender (P=0.64), operator (P=0.56) and cavity size (P=0.81) had no effect on the survival of the type of restoration observed. Type of tooth (P=0.004) and type of jaw (P=0.05) showed an effect. Severe wear was the major reason for restoration failure (ChemFil Rock=7; Fuji IX GP=1). SIGNIFICANCE: ChemFil Rock appears not to be a viable alternative to Fuji IX GP in restoring ART multiple-surface cavities in permanent posterior teeth.

Simple Bayesian testing of scientific expectations in linear regression models.

Scientific theories can often be formulated using equality and order constraints on the relative effects in a linear regression model. For example, it may be expected that the effect of the first predictor is larger than the effect of the second predictor, and the second predictor is expected to be larger than the third predictor. The goal is then to test such expectations against competing scientific expectations or theories. In this paper, a simple default Bayes factor test is proposed for testing multiple hypotheses with equality and order constraints on the effects of interest. The proposed testing criterion can be computed without requiring external prior information about the expected effects before observing the data. The method is implemented in R-package called 'lmhyp' which is freely downloadable and ready to use. The usability of the method and software is illustrated using empirical applications from the social and behavioral sciences.

Cation exchange capacity of biochar: An urgent method modification.

Biochar, produced through pyrolysis of organic matter, is negatively charged, thus contributing to electrostatic adsorption of cations. However, due to its porous structure and contents of alkaline ashes, the determination of the cation exchange capacity (CEC) is challenging. Literature values for the CEC of biochar are surprisingly variable and are often poorly reproducible, suggesting methodological problems. Here, we modify and critically assess different steps in the existing ammonium acetate (NH4OAc) method (pH 7), where ammonium (NH4+) is displaced by potassium chloride (KCl), following removal of excess NH4OAc with isopropanol, in batch mode. We used pigeon pea biochar to develop the method and conducted a test on three additional biochars with different acid neutralizing capacity. A pretreatment step of biochar was introduced, using diluted hydrochloric acid, to decrease biochar pH to near neutral, so that 1 M NH4OAc effectively buffers the biochar suspension pH at 7. This allows the CEC of all biochars to be determined at pH 7, which is crucial for biochar comparison. The dissolution of ashes may cause relatively large weight losses (e.g. for cacao shell biochar), which need to be accounted for when computing the CEC of raw biochar. The sum of NH4OAC-extractable base cations provided a smaller and better estimate of the CEC than KCl-extractable NH4+. We hypothesize that the overestimation of the CEC based on KCl-extractable NH4+ is due to the ineffectiveness of the relatively large isopropanol molecules to remove excess NH4OAc in biochars rich in micro-pores, due to size exclusion. The amount of base cations removed in the pretreatment was about three (rice husk biochar) to ten times (pigeon pea biochar) greater than the amount of exchangeable cations. The CEC values of biochar increased from 10.8 cmol/Kg carbon to 119.6 cmol/Kg carbon. These values are smaller than reported CEC values of soil organic carbon.

Calcium signalling links MYC to NUAK1.

NUAK1 is a member of the AMPK-related family of kinases. Recent evidence suggests that NUAK1 is an important regulator of cell adhesion and migration, cellular and organismal metabolism, and regulation of TAU stability. As such, NUAK1 may play key roles in multiple diseases ranging from neurodegeneration to diabetes and metastatic cancer. Previous work revealed a crucial role for NUAK1 in supporting viability of tumour cells specifically when MYC is overexpressed. This role is surprising, given that NUAK1 is activated by the tumour suppressor LKB1. Here we show that, in tumour cells lacking LKB1, NUAK1 activity is maintained by an alternative pathway involving calcium-dependent activation of PKCα. Calcium/PKCα-dependent activation of NUAK1 supports engagement of the AMPK-TORC1 metabolic checkpoint, thereby protecting tumour cells from MYC-driven cell death, and indeed, MYC selects for this pathway in part via transcriptional regulation of PKCα and ITPR. Our data point to a novel role for calcium in supporting tumour cell viability and clarify the synthetic lethal interaction between NUAK1 and MYC.

Controlled, synchronized actuation of microdroplets by gravity in a superhydrophobic, 3D-printed device.

Droplet manipulation over open surfaces allows one to perform assays with a large degree of control and high throughput, making them appealing for applications in drug screening or (bio)analysis. However, the design, manufacturing and operation of these systems comes with high technical requirements. In this study we employ a commercial, low-friction, superhydrophobic coating, Ultra-Ever Dry®, on a 3D-printed microfluidic device. The device features individual droplet compartments, which allow the manipulation of discrete droplets (10-50 µL) actuated by gravity alone. Simply by angling the device to normal in a 3D-printed holder and rocking in a "to and fro"-fashion, a sequence of droplets can be individually transferred to an electrochemical microelectrode detector and then to waste, while preserving the (chronological) order of samples. Multiple biological fluids (i.e. human saliva, urine and rat blood and serum) were successfully tested for compatibility with the device and actuation mechanism, demonstrating low slip angles and high contact angles. Biological matrix (protein) carryover was probed and effectively mitigated by incorporating aqueous rinse droplets as part of the analysis sequence. As a proof-of-concept, the enzyme-coupled, amperometric detection of glucose was carried out on individual rat serum droplets, enabling total analysis in ≈30 min, including calibration. The device is readily customizable, and the integration of droplet generation techniques and other sensor systems for different analytes of interest or applications can be realized in a plug and play fashion.

[Organ donation following physician-hastened death at home]. / Orgaandonatie na euthanasie vanuit de thuissituatie.

Patients considering physician-hastened death (PHD) increasingly express a wish to donate organs after death. This fairly unique proposition stems from patients' desire to do something good with (parts of) the same diseased body that has prompted them to request physician-hastened death. In this article we describe a patient with amyotrophic lateral sclerosis (ALS) who expressed this wish. In March 2017 a national guideline on 'Organ donation following physician-hastened death' (ODP) was presented to the Minister of Health, Welfare and Sport of the Netherlands. From the development of this guideline it emerged that, for PHD patients, being forced to experience their final conscious moments in hospital - in order to facilitate organ donation - was a key reason for not choosing ODP. Together with an anaesthesiologist-intensivist, the GP of the ALS patient developed a domestic ODP, thereby overcoming the hurdle of experiencing death in hospital and maintaining the possible option of organ donation. The applied solution is an 'anaesthesia bridge' which separates the experience of farewells, and losing consciousness under pre-medication at home, from biological death and organ donation in hospital.

Impact of a multifaceted strategy to improve perioperative diabetes care.

AIMS: To assess the impact of a multifaceted strategy to improve perioperative diabetes care throughout the hospital care pathway. METHODS: We conducted a controlled before-and-after study in six hospitals. The purpose of the strategy was to target four predominant barriers that obstruct optimal care delivery. We provided feedback on baseline indicator performance, developed a multidisciplinary protocol and patient information, and provided professional education. After a 6-month intervention, we determined the performance changes against three outcome indicators and nine process indicators using data on 811 patients with diabetes who underwent major surgery. The progress of the interventions was monitored closely. RESULTS: Two process indicators improved significantly in the intervention hospitals: the proportion of patients for whom glycaemic control had been evaluated preoperatively increased by 9% (P < 0.002) and the proportion of patients with blood glucose measurements within 1 h after surgery increased by 29% (P < 0.0001). Four other process indicators and all three outcome indicators improved more in the intervention hospitals than in the control hospitals, but the differences were not statistically significant. These included the proportion of patients with all glucose values at 6-10 mmol/l (+3%) and the proportion of patients with hyperglycaemia (-8%). The implementation of the multidisciplinary protocol was still ongoing after the 6-month intervention period. CONCLUSIONS: The multifaceted improvement strategy had a limited impact on the quality of perioperative diabetes care. This study demonstrates the complexity of improving perioperative diabetes care throughout the multiprofessional hospital care pathway.

Olfactory dysfunction in behavioral variant frontotemporal dementia.

OBJECTIVE: Several neurodegenerative disorders show olfactory dysfunction. In patients with frontotemporal dementia (FTD), olfactory impairment is probably due to the involvement of the temporal and orbitofrontal lobes. We hypothesized that due to the disrupted areas in FTD, there would be an impairment in smell identification, differentiation and association. Moreover, we hypothesized that there would be a correlation between the severity of FTD and the severity of odor dysfunction. METHODS: In the current study, we compared odor identification, discrimination and association of nine patients with behavioral variant FTD with eleven healthy controls using the Brief Smell Identification Test and the Odor Perception and Semantics Battery. RESULTS: The results showed significant differences in the odor association test, but not in the identification or discrimination test. There was no correlation between disease severity and the performance in the odor tests. CONCLUSION: We showed impairment of odor association that is most likely due to disruption of specific associative areas involved in olfactory processing. Specifically, we propose that the impairment may well be due to disrupted areas in the temporal lobe and amygdala.

Risk Factors for Sexual Transmission of Hepatitis C Virus Among Human Immunodeficiency Virus-Infected Men Who Have Sex With Men: A Case-Control Study.

Background. Since 2000, incidence of sexually acquired hepatitis C virus (HCV)-infection has increased among human immunodeficiency virus (HIV)-infected men who have sex with men (MSM). To date, few case-control and cohort studies evaluating HCV transmission risk factors were conducted in this population, and most of these studies were initially designed to study HIV-related risk behavior and characteristics. Methods. From 2009 onwards, HIV-infected MSM with acute HCV infection and controls (HIV-monoinfected MSM) were prospectively included in the MOSAIC (MSM Observational Study of Acute Infection with hepatitis C) study at 5 large HIV outpatient clinics in the Netherlands. Written questionnaires were administered, covering sociodemographics, bloodborne risk factors for HCV infection, sexual behavior, and drug use. Clinical data were acquired through linkage with databases from the Dutch HIV Monitoring Foundation. For this study, determinants of HCV acquisition collected at the inclusion visit were analyzed using logistic regression. Results. Two hundred thirteen HIV-infected MSM (82 MSM with acute HCV infection and 131 MSM without) were included with a median age of 45.7 years (interquartile range [IQR], 41.0-52.2). Receptive unprotected anal intercourse (adjusted odds ratio [aOR], 5.01; 95% confidence interval [CI], 1.63-15.4), sharing sex toys (aOR, 3.62; 95% CI, 1.04-12.5), unprotected fisting (aOR, 2.57; 95% CI, 1.02-6.44), injecting drugs (aOR, 15.62; 95% CI, 1.27-192.6), sharing straws when snorting drugs (aOR, 3.40; 95% CI, 1.39-8.32), lower CD4 cell count (aOR, 1.75 per cubic root; 95% CI, 1.19-2.58), and recent diagnosis of ulcerative sexually transmitted infection (aOR, 4.82; 95% CI, 1.60-14.53) had significant effects on HCV acquisition. Conclusions. In this study, both sexual behavior and biological factors appear to independently increase the risk of HCV acquisition among HIV-infected MSM.

Caries-preventive Effect of Supervised Toothbrushing and Sealants.

To investigate the effectiveness of 3 caries-preventive measures on high- and low-caries risk occlusal surfaces of first permanent molars over 3 y. This cluster-randomized controlled clinical trial covered 242 schoolchildren, 6 to 7 y old, from low socioeconomic areas. At baseline, caries risk was assessed at the tooth surface level, through a combination of ICDAS II (International Caries Detection and Assessment System) and fissure depth codes. High-caries risk occlusal surfaces were treated according to daily supervised toothbrushing (STB) at school and 2 sealants: composite resin (CR) and atraumatic restorative treatment-high-viscosity glass-ionomer cement (ART-GIC). Low-caries risk occlusal surfaces received STB or no intervention. Evaluations were performed after 0.5, 1, 2, and 3 y. A cavitated dentine carious lesion was considered a failure. Data were analyzed according to the proportional hazard rate regression model with frailty correction, Wald test, analysis of variance, and t test, according to the jackknife procedure for calculating standard errors. The cumulative survival rates of cavitated dentine carious lesion-free, high-caries risk occlusal surfaces were 95.6%, 91.4%, and 90.2% for STB, CR, and ART-GIC, respectively, over 3 y, which were not statistically significantly different. For low-caries risk occlusal surfaces, no statistically significant difference was observed between the cumulative survival rate of the STB group (94.8%) and the no-intervention group (92.1%) over 3 y. There was neither a difference among STB, CR, and ART-GIC on school premises in preventing cavitated dentine carious lesions in high-caries risk occlusal surfaces of first permanent molars nor a difference between STB and no intervention for low-caries risk occlusal surfaces of first permanent molars over 3 y.