Introduction

Cerebral palsy (CP) is a term used to describe a group of permanent and progressive disorders affecting movement and posture that result from injury or insult to the developing brain.1 Cerebral palsy is the most common physical disability of childhood, occurring in two of every 1000 live births in developed countries, and it is a lifelong condition.2 The causal pathways to CP are complex and not yet fully understood. However, there are many recognized risk factors such as male sex, multiple birth, low birthweight and preterm birth.2 In addition to the functional movement limitations that people with CP experience, there are a number of frequently occurring co-morbidities including, but not limited to: epilepsy, communication disorders, intellectual impairment, and hearing and vision loss.2 These co-morbidities can impact on participation in daily activities, and general health and well-being.3

An additional and commonly overlooked condition associated with CP is poor oral health. Oral health is essential to general health and quality of life, and poor oral health can be a known cause of disability. Conversely, general health problems may cause or worsen oral health conditions.4 The World Health Organization (WHO) states that "oral health is a key indicator of overall health, wellbeing and quality of life."5^[para.1] Oral health is defined as "a state of being free from chronic mouth and facial pain, oral and throat cancer, oral infection and sores, periodontal (gum) disease, tooth decay, tooth loss, and other diseases and disorders that limit an individual's capacity in biting, chewing, smiling, speaking, and psychosocial wellbeing."5^[para.1] One important key factor of good oral health is adequate quality and quantity of saliva, which assists in maintaining oral health via its actions of protection, lubrication and cleansing for teeth and oral tissues. In addition, saliva plays an important role in swallowing and digesting food, and is also vital in the remineralization of dental decay and protecting teeth against demineralization that can lead to dental decay.6 Currently, in the general population, 50% of five-year-old children and nearly 65% of nine-year-old children are reported to have had decayed, missing or filled deciduous teeth. Poor oral health affects many individuals, with approximately 16% of those aged between 15 and 64 experiencing toothache in the previous 12 months, over a quarter of the same age range being dissatisfied with the appearance of their teeth, and approximately one-third of this population avoiding certain types of food due to tooth-related problems.7

The burden of dental disease is reported to be increasingly prevalent in individuals with disabilities, including CP, as evidenced by the higher risk for dental caries, increased number of dental anomalies and fourfold increase in dental trauma compared to children without disabilities.8 Furthermore, a recent study that focused on children in a low-resource setting reported decay rates of approximately 70% for children with CP between seven and 11 years of age.9 Individuals with CP are also more susceptible to oral health issues due to the reported dental implications associated with preterm birth, a known risk factor for CP.2 Dental issues associated with preterm birth include, but are not limited to: delayed tooth eruption, developmental enamel defects and enamel trauma. These dental problems, coupled with the neuromuscular effects of CP, have been shown to cause changes to oro-facial structures, negatively impacting nourishment, oral hygiene and resulting in parafunctional habits of the mouth, jaw and tongue. This can in turn negatively affect self-esteem and self-confidence, particularly in social situations.10,11 There is emerging evidence to suggest that children with CP are at significant risk of developing sleep apnea and have increased risk of difficulties with sleep problems as a result of dental-related conditions such as drooling, bruxism (grinding or jaw clenching) and pain.12 It is estimated that three out of four people with CP experience chronic pain.13 Dental pain is likely contributing to this pain due to the high prevalence of bruxism, oral trauma (due to seizures), dental caries, enamel defects, erosion and chronic gum disease.2,7,11-14

The limited available literature suggests that individuals with CP are at increased risk of poor oral health and dental-related pain. A preliminary search of databases including Scopus, MEDLINE, JBI Database of Systematic Reviews and Implementation Reports, and Cochrane Oral Health that was conducted in September 2018 revealed a paucity of quality research regarding oral health of people with CP, particularly in the adult population. Currently, there is one systematic review that reports on oral health in children with CP8; however, this study did not consider reported dental problems for people with CP such as dental pain, tooth diseases, bruxism or saliva-related factors. At present, there are no documented systematic reviews reporting on oral health outcomes for people of all ages with CP. Subsequently, there are no clear guidelines, frameworks or detailed oral health recommendations for people with CP in Australia or globally. Considering the importance of oral health on general well-being and quality of life, it is important that oral health is not overlooked when focusing on patient-centered care for people with CP. Additional targeted research is required to better understand the oral health concerns for all ages of this at-risk population, with the end goal of improving oral health outcomes and wellbeing for people with CP.

A traditional systematic review to begin this process is impractical, because the term "oral health" is a broad multi-faceted term that encompasses a range of conditions. It has been determined by the authors that a scoping review is the most practical way to gain an overall picture of oral health needs of people with CP. Scoping reviews are increasingly utilized in the literature, not only to assess the quality of existing research but also to map ideas, clarify definitions, provide an overview of a broader topic and provide future direction for systematic reviews. The purpose of this scoping review is to systematically review and compile all relevant research in the literature to identify oral health outcomes experienced by people with CP. This will inform future research in the form of a Delphi study, with the aims of providing targeted and specific oral health recommendations, informing policy, and improving the general health of people with CP. This research will help determine effective oral health outcomes, including reported risk factors (e.g. premature birth, diet), oral health outcomes (e.g. dental caries, dental pain), and/or oral health-related quality of life experienced by people with CP.

Review question

What types of oral health-related concerns, outcomes and experiences have been reported for people with CP?

Inclusion criteria

Participants

This scoping review will consider any global, pertinent oral health studies that include people with CP with no participant exclusion criteria pertaining to age, ethnicity or sex.

Concept

The concept of interest for the scoping review is oral health outcomes experienced by people with CP. Articles that focus on oral health, including dental diagnosis, trauma and treatment, oral health, facial pain, saliva, sleep apnea, and/or make statements regarding oral health pertaining to CP will be considered for inclusion in this scoping review.

Context

This review will include all studies evaluating oral health and/or reporting on oral health concerns of people with CP that are conducted in dental clinics, dental hospitals, hospitals, healthcare settings, acute care, primary care, special care, the community or in a home-care environment.

Types of studies

This scoping review will consider quantitative and/or qualitative evidence from study designs such as systematic reviews, randomized controlled trials, non-randomized controlled trials, prospective and retrospective cohort studies, case control studies/reports and cross-sectional studies that report on oral health concerns or improved care for people with CP. In addition to research studies, unpublished studies will be considered from the gray literature including opinion papers and reports, expert opinions, discussion papers, position papers, abstracts and conference proceedings.

Methods

Search strategy

The review will be conducted in accordance with guidelines outlined by JBI methodology for scoping reviews and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR): Checklist.15-17 The comprehensive search strategy has been developed in conjunction with a specialist health research librarian and aims to find both published and unpublished studies (including gray literature). A three-step search strategy will be utilized; the first step will include a search of MEDLINE and CINAHL, followed by a text analysis of the words contained in the title and abstract (in addition to the index terms used to describe the article). Subsequently, all identified keywords and index terms across all included databases will be searched. A proposed search strategy for MEDLINE is shown in Appendix I.

Articles published in any language will be considered, with no restriction on publication date for inclusion in this review. All references from identified reports will be hand reviewed to determine if the literature is appropriate for inclusion in this scoping review. Where applicable, authors of primary studies will be contacted for more information. The title of this scoping review protocol was registered with JBI in June 2018.

Information sources

The database search will include the following: Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials (CENTRAL), Web of Science, Scopus, Embase and Dentistry and Oral Science.

A search of the gray literature will consider ProQuest Dissertations and Theses, Google Scholar, conference abstracts and proceedings, Analysis Policy Observatory (APO), Government websites (e.g. Australian Institute of Health and Welfare; Australian Commission on Safety and Quality in Health Care) and National Health and Medical Research Council.

Study selection

Upon completion of the search, all citations will be collated and uploaded into the reference management software package EndNote V8.2 (Clarivate Analytics, PA, USA) and duplicates removed. Selected studies identified for the scoping review will be retrieved using the inclusion and exclusion criteria and recorded using the results extraction instrument template from the JBI Reviewers' Manual. Reasons for exclusion of full-text studies will be provided in an appendix in the final scoping review. Assessment of selected papers will be performed by two independent reviewers. Any disagreements that arise between the reviewers will be resolved through consensus or if unresolved, via a third reviewer.15 A flow diagram following the PRISMA-ScR method will tabulate the process of identification, screening, eligibility and inclusion criteria.

Data extraction

Data relevant to the scoping review that report on oral health outcomes experienced by people with CP will be extracted by two reviewers. The reviewers will independently document and tabulate this data in accordance with JBI methodology to include specific study details as shown in Appendix II.

Data presentation

Detailed information on selection criteria including objectives, methods and key findings will be presented. Conceptual categories such as country of origin, reported clinical findings/types of interventions, study population (including sample sizes) and duration of study will also be reported. To support the results, a summary of the selected and excluded sources and results will be included as an appendix as part of the final review, along with a tabulated and narrative discussion reporting on the presentation of these findings. Proposed tables are shown in Appendices III and IV.

Acknowledgments

The authors would like to acknowledge the assistance of Edward Luca and Jessica Hughes, the Faculty of Medicine and Health librarians at the University of Sydney, and advise that the manuscript has followed the double-blind peer review guidelines. This review will contribute towards a Doctor of Philosophy degree for the first author, KL.

Appendix I: Search strategy for MEDLINE via Ovid

Appendix II: Data extraction tool

Appendix III: Characteristics of included studies

Appendix IV: Oral health outcomes

References