Oral Health Care
Caring for one's teeth and mouth, or oral health care (OHC), is a fundamental aspect of self-care. Typically we care for our own teeth in an independent, individualised manner which requires little thought, but which reflects our individual oral health needs, preferences, standards and patterns of behaviour. Some will occasionally (if at all) seek professional intervention in the form of an annual or bi-annual visit to the dentist . Therefore the components of OHC may be perceived at one level as a series of relatively simple tasks or interventions. However, where there is an acquired deficit in an individual's cognitive capacity or physical ability, as might occur following a stroke, that individual may become partially or totally reliant upon others to ensure their oral health, temporarily or on a continuing basis. Thus the potential complexity of providing or supporting OHC across a patient population with a range of abilities, with varying (or even changing) OHC needs whilst also ensuring they maintain (or attain) good oral health becomes more apparent.
Oral Health Care after Stroke
Many individuals experience stroke related physical, cognitive, visual or sensory deficits which may make independent OHC difficult. Swallowing, chewing and oral clearance difficulties as a result of the stroke may leave food or fluid residue within the mouth for prolonged periods of time, contributing to dental decay . In addition, for people with stroke related swallowing difficulties, medication may be provided in a syrup based consistency which may also inadvertently contribute to dental problems. Known side effects of medication or treatment prescribed following stroke may also impact upon oral health (for example, dry mouth, oral ulcers and stomatitis) . Some individuals experiencing such stroke related challenges to maintaining oral health may also experience these difficulties in the presence of pre-existing oral health problems [1, 4] further compounding oral health risks. Many patients within the stroke care setting may be partially or totally reliant upon nursing assistance to ensure their oral health .
Before any new OHC intervention can be developed and evaluated there needs to be a strong theoretical underpinning for that intervention . Undertaking a considerable programme of pre-clinical work  we conducted a Cochrane systematic review and found a very limited evidence base . Stroke specific data from a small randomised controlled trial (RCT) of an OHC educational intervention for staff based in a nursing home setting reported positive benefits to residents' denture cleanliness (but not dental cleanliness) as a result of a staff training intervention [8, 9]. Some patient subgroups were excluded - for example those with significant cognitive impairment and those who were edentulous (who had neither natural teeth nor dentures). Other more recent RCTs have examined periodontal therapy  or an oral decontamination gel , neither of which could be considered 'routine' oral health care. Two trials that did aim to evaluate complex OHC interventions investigated a ventilated post stroke population  and a nursing home population . Both trials were problematic methodologically. The nursing home population were a highly selected group that excluded those that were unwell, cognitively incapacitated or receiving palliative care  - patient subgroups at high risk of oral health problems and requiring the most intensive OHC support. In contrast, the trial with the ventilated population was terminated before completion and only reported data on the incidence of pneumonia .
Many interventions delivered within the stroke rehabilitation setting could be considered complex, though some are more complex than others, occurring at different points along what could be considered a spectrum of complexity . The degree of complexity might be gauged on the basis of the number of; components within the intervention (and the interactions between those components); actions required from participants; actions required from those delivering the intervention; organisational levels the intervention is targeting; and outcome measures employed . Others describe complexity at a systems level  urging careful consideration of the clinical context in which an intervention is delivered. In practice, both the intervention and the systems within which it operates are relevant thus the number of systems could also be considered in relation to the degree of complexity. For example, an OHC intervention is delivered to a patient, by staff operating as a team within a ward, which in turn is nested within a hospital, which may be further supported by external specialist dental support services (as required). For the OHC intervention to work the intervention must function within, and be supported by, the team, ward, hospital and external services.
Researchers however have often strived to simplify research questions. Reducing variability in the participants, the intervention, the delivery and/or the context and introducing consistency across these parameters with the aim of increasing internal and construct validity i.e. an efficacy study . However such a narrow approach to intervention evaluation comes at the expense of external validity. As a consequence, many evaluations of OHC interventions after stroke recruited very narrow patient populations, delivered very specific oral healthcare protocols which were implemented by specialist researchers or healthcare staff that were atypical within the normal clinical setting. As a result there are limitations on the clinical relevance of the study leading to delayed translation into clinical practice .
In contrast, drawing on and accommodating the known components of complexity during the development and evaluation of an OHC intervention, informs the development of a clinical effectiveness study . Thus a clinically feasible, adaptable OHC intervention is delivered to a heterogeneous, clinically representative post stroke population within a typical stroke healthcare setting by a typical stroke rehabilitation team. Should it prove effective, capturing data on the interactions observed within and between components of the intervention, and the systems across which the intervention is delivered, will facilitate the translation of the research into practice [15, 16].
Delivery of complex, clinically embedded interventions, within a healthcare context does not occur in isolation. As such, researchers need to consider the consequences of potential interactions between the intervention and the 'system' (context in which it is delivered) in designing and evaluating the intervention . Thus capturing information on contextual factors is essential in clinical research . Evidence relating to the availability of training, expertise, equipment, products and support services aids interpretation of the study results and allows consideration of the intervention's applicability within other settings or contexts. Evaluating the implementation or feasibility of a pilot intervention provides evidence which enables judgements relating to the need for and extent of adaptations or modifications on an individual or local systems level (e.g. for each specific ward) . It is only by collecting and reporting these contextual factors that the translation of the research into clinical settings can be facilitated .
Through our extensive preclinical work we found that staff in hospital based stroke care settings experience limited access to training opportunities, OHC policies and in some cases even basic OHC equipment such as toothbrushes and toothpaste . Nursing staff are clearly motivated but general support for the provision of OHC is often inadequate . With a range of competing clinical priorities OHC is often delegated to unregistered members of the stroke multidisciplinary team (MDT) such as clinical support workers, student nurses or even family members . Clearly there is an urgent need to generate evidence to underpin the provision of high quality, well supported OHC in stroke care settings using a pragmatic randomised controlled trial design which compares usual OHC with an experimental complex OHC intervention.
We believe that a successful OHC intervention within the stroke care setting (or system) requires an intervention that is cognisant of the local (and wider healthcare) context and is thus delivered across three levels of care - patients, staff and services. Participant recruitment needs to be inclusive of patients that are most reliant upon staff for their OHC such as those with reduced levels of consciousness, severe cognitive impairment or severe communication impairment
The quality of the OHC delivered is also thought to be dependent on staff knowledge of and attitudes towards OHC . Specially trained staff might be expected to conduct an assessment of OHC, establish the degree and frequency of OHC support required, refer to dental specialists (as required) and develop a care plan in response to patients' OHC needs. In order to support OHC activities OHC tools, products, equipment, specialist training and dental services should be available to both staff and patients on the ward. Some individualisation of the OHC routine by patients and staff might be expected. Staff develop individualised care plans which reflect individual patient's needs and personal preferences based on their level of consciousness, cognitive or physical ability, sensory impairment, rehabilitation targets and pre- and post-stroke oral health. Where possible, patients might be expected to undertake their own OHC.
The success of any planned intervention within the context of a multidisciplinary stroke rehabilitation environment should also consider contributions to the intervention from others within the rehabilitation team including nurses, clinical support workers, physicians and occupational therapists. In addition, specialist dental support from outside the ward (e.g. community dentists, NHS Primary Care dental services) may also be required for more urgent oral health issues.
Given this degree of complexity identifying a single primary outcome measure to capture the impact of an OHC intervention is problematic . We would anticipate that a multifaceted OHC intervention would impact upon a range of components including for example dental referrals, staff knowledge and patients' oral health. Capturing the impact on dental health alone would need to accommodate a range of dental profiles including those with dentures, natural teeth, a combination of dentures and natural teeth or those who are edentulous (i.e. with neither). Different types of dentition (if any) could be positioned in different locations in each individual's mouth. Thus a carefully selected range of measures may best capture the impact of the intervention across the different dimensions targeted .
Piloting the Implementation
The challenges faced in evaluating such a complex intervention are considerable. Neither quantitative nor qualitative approaches alone would provide an adequate insight into the implementation of the intervention across all three levels of care, from the perspective of all involved and capture the information needed in relation to both effectiveness and feasibility issues. Following our pilot study we also wanted to be able to further refine the planned outcome measures for use within a randomised trial, examine the value of each measure used and to consider the need for any additional measures to capture unexpected effects which became apparent during the course of the pilot.
We aimed to pilot the implementation of a complex OHC intervention across multiple levels of care, adopting an inclusive approach to patient recruitment and a pragmatic approach to the delivery of the experimental OHC intervention. To ensure the data we collected provided a complete picture of the implementation of the complex intervention we used a mixed methods approach, with quantitative and qualitative approaches providing complementary evidence . We aimed to capture evidence relating to the impact of the intervention across components of care, the feasibility of our proposed approach within the pilot site and to highlight any aspects of the intervention that needed to be improved all of which would inform the design and conduct of a future randomised controlled trial.