Introduction
Recently, the World Dental Federation [FDI] proposed a new definition and theoretical framework of oral health, intending to move dentistry from the traditional focus on treatments towards oral health promotion and support [
1]. The FDI’s definition and theoretical framework describe oral health as multifaceted and changeable, including oral diseases/conditions, pain and discomfort, as well as aspects of physical and psychosocial functions and abilities essential to our everyday life [
2]. Oral health and general health and well-being are intertwined with determinants in daily life, but also with biomedical associations, for example there are connections among periodontal diseases and systemic or metabolic diseases/disorders such as cardiovascular diseases and obesity [
3‐
5]. Thus, determinants for oral and general health could be targeted simultaneously as both are affected by the circumstances in which we live, work, and become older [
2,
6,
7]. However, even if obstructive sleep apnoea [OSA] and periodontal diseases previously have been associated through systemic inflammation as well common risk factors from everyday life (e.g. ageing and tobacco use), the association between OSA and oral diseases has remained unclear. Few studies regarding dental caries have been performed [
8], and there is a need for more research on OSA and periodontal disease [
9,
10], but also the patient perspective on if and how OSA and CPAP-treatment might affect the oral health.
Characterised by repeated episodes of physical obstructions in the upper airway, OSA is defined as a sleep-related breathing disorder. Risk factors for OSA include obesity/overweight, male sex, postmenopausal state in women, and older age [
11], and it is estimated to affect approximately 900 million persons globally [
12]. The obstruction often causes heavy snoring and impedes the airflow completely (apnoea) or partially (hypopnoea), causing disturbances in the breathing process and desaturation, and is associated with cardiovascular diseases such as hypertension [
11]. To describe the severity of OSA, the metric tool the Aponea Hypopnoea Index [AHI] is commonly used where AHI 5–14.9 indicates mild, 15–29.9 moderate, and ≥ 30 severe OSA. However, it is also important to consider comorbidities and the effect on everyday life when deciding treatment [
11]. Continuous Positive Airway Pressure [CPAP] has been described as the primary choice of treatment for symptomatic OSA and, if used correctly, is an effective, often life-long treatment [
11]. The CPAP mask covers the face or mouth and/or nose, and adequate adherence is often defined as 4–5 h/night at least five nights/week [
11,
13].
Untreated OSA can affect the quality of life as well as increase the risk for conditions such as systemic hypertension, stroke, and type II diabetes, which makes adherence to treatment essential [
14‐
16]. Difficulties adapting to treatment and side-effects are some of the reasons why approximately 30% of all CPAP users abandon their treatment [
17,
18]. Frequently reported side-effects affecting adherence include xerostomia, blocked up nose, mask leaks, and mask pressure [
19]. In two studies focusing on oral health related experiences during CPAP treatment as described by CPAP users, several experiences were lifted [
20,
21]. Xerostomia, increased mouth-breathing, and a feeling of an deteriorating oral health in general was among the negative experiences [
20] as well as excessive saliva, xerostomia, and shifting bites [
21]. One of the most reported side-effects of CPAP treatment is xerostomia which has been associated with treatment abandonment within the first year [
18,
19,
22‐
26]. However, to our knowledge, research on the association between oral health and OSA has previously been performed from a biomedical or technical perspective with focus on treatment with oral appliances or periodontal disease, and research on other aspects of oral health and the patient perspective is scarce.
By using the FDI’s framework to explore oral health determinants in a specific population with an increased risk (i.e. due to CPAP-treated OSA) for negative consequences regarding both general and oral health, we can explore how persons with experience of CPAP-treatment view factors that affect their oral health. Creating a common ground for communication could help oral healthcare professionals and CPAP-practitioners to provide person-centred care and could enable shared decision-making within dentistry [
27‐
29].
Discussion
To the best of our knowledge, this study is the first to explore oral health determinants from the perspective of persons with long-term experience of CPAP-treated OSA by using the FDI’s theoretical framework of oral health. The FDI’s definition and theoretical framework [
2] was useful to describe and categorise the variety of views of oral health determinants that were expressed by the persons in the study. The qualitative data also added descriptions of some complex interactions between determinants and the informants’ experiences of adapting to changes in their life situation. Previously, studies have focused on and shown that OSA and oral diseases are associated with biomedical factors (e.g. through systemic inflammation) such as cardiovascular diseases and metabolic disorders e.g. obesity and diabetes mellitus [
3,
5,
11], and that xerostomia is a common side-effect of CPAP-treatment [
18,
19]. Due to the increased risk for adverse oral health outcomes for this patient group, the knowledge provided in this study can hopefully increase the understanding of oral health during CPAP-treatment for oral healthcare personnel and CPAP-practitioners.
Early life experiences, genetic predisposition, and saliva were viewed as influential oral health determinants which could have immediate consequences or affect the informant’s oral health throughout life. Their views correspond to the consensus report on the interactions among lifestyle, behaviour, and systemic and oral diseases [
38], where genetic predisposition and acquired risk factors for dental caries and periodontal diseases were described. The informants considered their saliva to affect their oral health, but the underlying reasons were often considered to be more unclear. They associated their experience of xerostomia with their CPAP-treatment but also described more complex interactions among their treatment, becoming older, and breathing through their mouth. This ambivalence regarding the cause of xerostomia is understandable, as there can be several causes, such as increasing age, medication use, and systemic diseases [
39,
40]. However, xerostomia has been associated with OSA [
22,
41] and is a commonly reported side-effect of CPAP-treatment that can affect adherence [
19,
42]. Therefore, it is important that both CPAP-practitioners and oral healthcare personnel can identity signs and possible cause of xerostomia to provide adequate treatment to prevent adverse oral health outcomes and to reduce or eliminate the person’s difficulties.
The community and the immediate family were described as influential throughout life on the informants’ oral health, from childhood until today. The parental influence and communicative behaviour have previously been shown to affect children’s understanding of oral health and their oral health behaviour [
43], and in a study on independent Canadian elderly, oral healthcare utilisation habits were shown to be formed during childhood and to continue though adulthood as normative behaviour [
44]. In this population, understanding of the impact of their upbringing on their oral health habits was seemingly of specific importance. Establishing appropriate oral health behaviour at an early age, considering the child and the living social environment (e.g. family, community) [
45], is of importance for oral health outcomes in later life. The findings also showed the value of community-driven programmes promoting oral health in adulthood, such as oral healthcare campaigns on tooth-brushing and diet.
Besides the views on influential factors in the informants’ childhood, changes in the local environment in adulthood during CPAP-treatment were viewed to have an impact on their oral health, such as the experience of xerostomia. They connected this with changes in air humidity and increased prevalence of having a blocked-up nose due to seasonal changes. Previously, seasonal changes (i.e. air humidity) have been reported to affect CPAP-adherence in a Japanese population [
45] where most of the persons adhered to their treatment; however, possible seasonal changes in adherence were not further explored in this study. In addition to changes in the level of xerostomia, the informants in the current study also described how a change in location could affect their oral hygiene. The findings suggest that circumstantial changes in the environment could affect the level of xerostomia, CPAP-adherence, and oral health habits in this population.
Motivation and willingness to change affected the informant’s behaviour, where support from oral healthcare personnel contributed either as a facilitator or barrier. CPAP-treatment was viewed to have increased their awareness of their oral health and therefore changed their oral hygiene habits to prevent adverse oral health outcomes. As CPAP-treatment is often life-long, it is important for CPAP-users to maintain positive changes in oral health behaviour for a long time. Previously, it has been reported that several factors (e.g. emotions, motivation, and functional and cognitive abilities) can affect a person’s ability to maintain adequate oral hygiene with increasing age [
46]. The informants described different views on their willingness and ability to change. In view of these individual differences in motivation for change, person-centred care seems appropriate [
28]. This means that oral healthcare personnel may need to maintain or create more trusting oral healthcare encounters and develop shared decision-making further within their clinical context, to accommodate personalised recommendations [
29]. Furthermore, the informants’ views on access to oral healthcare were described as a wider concept than just availability. The informants included aspects such as control, finances, organisation, and trust. Creating a trusting environment is important as trusting relationships have previously been described to increase the utility of services, increase adherence to preventive care, and enable oral health care personnel to carry out high quality care [
44,
47]. However, there seems to be a lack of knowledge or experience of patients with OSA and the association with oral health among oral healthcare personnel [
48].
Based on the findings in this study some recommendations for clinical practice can be highlighted. The knowledge provided in this study could be useful in both identifying oral health needs as well as tailoring oral healthcare to this specific population. Person-reported information regarding oral health related barriers and facilitators for CPAP-treatment adherence is therefore significant. For oral health care personnel, it is important to create trustful relationships to promote beneficial oral health habits including regular visits over time, further implement shared-decision-making, and increase interprofessional collaboration with CPAP-practitioners. For CPAP-practitioners, identifying oral health-related side-effects of CPAP-treatment and providing adequate recommendations can be a challenge as studies on the patient perspective on oral health during CPAP-treatment are scarce. Therefore, it is suggested that future studies focus on the patient perspective on real-life oral health-related experiences before and during CPAP-treatment. However, until then, CPAP-practitioners could ask their patients regarding known side-effects such as xerostomia as a first step to include oral health within CPAP care.
Finally, some methodological considerations should be noted. All persons eligible to participate in the interviews (i.e. participated in the initial dental examinations and with experience of CPAP treatment) were invited to participate. Of the potential 42 informants, 18 persons chose to participate which was regarded as sufficient based on the predetermined aim of 15–20 informants. The informants had previously participated in research projects and were familiar with the research context. In addition, the informants had also met the interviewer (first author, who is a dental hygienist) in person before and/or been in contact with her per telephone which was clarified in the information letter. In our study, this enabled in-depth descriptions and had a positive effect on the informants’ willingness to share their experiences. By the initial inductive approach, all views from the informants were considered for inclusion. The following deductive coding process allowed us to describe the determinants in a comprehensive way while still maintaining focus on the views described by the informants. Although face-to-face interviews, as originally planned, would have been optimal, telephone interviews are common and accepted as a method for data collection [
49]. But even if this way of collecting data increase the risk of missing non-verbal forms of communication, the focus in this study was on the manifest content making telephone interviews a suitable method for data collection. The following measures were taken to increase the trustworthiness of the findings [
50,
51]. The procedure of purposeful selection of 18 informants resulted in a variety of views of persons with different real-life experiences, which ensured the sample’s heterogeneity. However, more male than female informants participated in the study which probably is due to the differences in prevalence of OSA [
11]. This should be considered when assessing the transferability to other contexts. Furthermore, several measures were taken to increase the credibility of the study. First the interview guide was discussed and revised by the research group, consisting of persons with experience and expertise within oral health and sleep medicine, but also methodology, several times. Then pilot interviews and pre-tests were performed to assess the relevance for the area of interest and to ensure an adequate item sequence during the interviews. We also aimed to provide detailed information (e.g. study context, analytic process) to increase the credibility of the findings. Throughout, repeated discussions within the research group, who had access to all material during the analytic process, were performed until consensus was achieved.
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