Dental care for the bariatric patient

Epidemiology of obesity

Body mass index is the commonest used tool to describe patient weight. It is a simple height to weight index (mass in kg/height in metres²) used to classify whether an adult's weight is underweight, normal, overweight, or obese. Overweight is defined as a body mass index exceeding 25 kg/m2 while obesity is a BMI exceeding 30 kg/m2.¹ Generally, higher levels of obesity are most strongly associated with significantly worse health outcomes and the number of conditions associated with overweight and obesity have made these conditions a public health priority in the UK.^4,5

Worldwide, in 2016, 1.9 billion adults were classified as overweight, with 650 million people classified as obese.¹ In the UK, 26% of adults are classified as obese.⁶ Although the rate at which obesity is increasing has steadied,⁴ the overall prevalence of obesity has tripled since 1975, creating substantial problems for healthcare systems.¹ In the UK there are significant regional variations in obesity, and obesity led to 617,000 hospital admissions in 2016–17 (an increase of 18% from 2015–16).⁶ Although there are no data on the extent of obesity in dental attenders, the growing level of obesity has far-reaching implications for both general and specialist dental services.

Access to clinic and patient facilities

For the majority of bariatric (ie relating to the treatment and causes of obesity) patients, getting to a dental surgery is possible using their own transportation. As their weight increases, mobility and transportation can pose problems that require careful assessment and management by the dental team. Features such as patient's weight, any postural considerations, the ability to walk, or wheelchair-requirements are helpful when assessing or referring. Assessment in a domiciliary setting may be required to clarify the transportation needs, risk assess the dental surgery requirements, and draft a provisional dental treatment plan. Ambulance or bariatric ambulance transportation may be required, and consideration of appointment timing is essential to ensure patients are delivered to, and collected from, the dental surgery at convenient and appropriate times. Bariatric ambulance transportation in many regions is by an emergency bariatric ambulance. This may become unavailable at short notice with consequent delays in patient transfer.

Some bariatric patients are travelling long distances to find dental treatment and have increased waiting times for treatment due to lack of facilities. ‘Shared care’ between GDPs and specialist services can help with this, although there can be difficulties with GDPs having the basic facilities for Bariatric patients.

Once at the dental clinic, the dental waiting room must have a bariatric chair of the appropriate size and weight limit for patients waiting for appointments (Figure 1). The impact of different body types/shapes is important in choosing chair design and appointment length. In addition, toileting facilities (Figure 2) must be adequate for these patients: door width; grab handles; toilet area size; toilet seat height; and toilet seat/pan weight limit all require assessment and reasonable adjustments.

The average width of a UK internal door is 76.2 cm and while a normal wheelchair width is 66 cm, a bariatric wheelchair width may be up to 83.8 cm. Doors to the waiting room and dedicated surgery may require widening to allow access for bariatric wheelchairs, trolleys and hoists. The space requirement for wheelchair positioning and movement in the surgery must be considered. While many overweight or obese patients can mobilize and transfer independently, a bariatric Zimmer frame, banana board and PAT slide may aid the transfer of patients who can mobilize from wheelchair to the dental chair. Some patients may be unable to weight-bear due to the physical impact of obesity and the impact of comorbidities. For these patients, the weight limit and suitability of hoist equipment needs to be formally assessed as a component of risk management to ensure compliance with manual handling legislation.

Equipment and dental chairs

Most UK dental chairs have a safe maximum operating load in the range of 23–25 stone (146–158 kg). For patients over this weight, there are different types of bariatric dental chair available, two of which are most commonly used in community or hospital settings. The first style comes as a dedicated fixed dental chair. Figure 3 shows the Barico chair (Diaco Ltd, UK), which can be used to treat patients up to 71 stone (454 kg). As well as supporting larger weights, it is 15–20 cm wider than a normal dental chair and has a low starting height with fully functional arm and head rests.

The second design is that of a combined recliner and bariatric bench. These serve a dual purpose as patients who use a wheelchair, including bariatric wheelchairs, can remain in their own chair that can be reclined for treatment delivery. This avoids the need for manual transfer or hoisting of patients. For ambulatory patients, a bench (Figures 5 and 6) can be inserted into the reclining base. The Design Specific Bariatric Bench and Wheelchair Recliner (Design Specific Ltd, UK) is shown in Figures 4–6, which can be used to treat patients up to 59 stone (375 kg). Bariatric chairs are costly to purchase, install and maintain because they require annual maintenance by accredited engineers. They are usually found in the community dental service or dental hospitals, and while they are able to be used for all patients, their size limits their practicality for treating many patients.

Health and safety

Dental professionals have both a duty of care to all patients and a legal obligation under the Health and Safety at Work Act 1974 to operate in a safe environment. It is important not to exceed the safe working limit of the dental chair to avoid patient or staff injury resulting from chair collapse. Furthermore, using equipment outside the limitations and recommendations of the manufacturer may invalidate any public and emplyee liability insurance. Dental professionals have a legal obligation to provide care for these patients and referral to a specialist unit may be required if facilities are unavailable.

Of all NHS staff sickness absence, 40% is due to musculoskeletal problems such as back pain, which can have an enormous impact on the quality of life of those affected.⁷ Dental staff, particularly those who assist in mobilizing patients or treat obese patients on a domiciliary basis, require specific moving and handling training to avoid injury to themselves.⁸ Owing to patients' increase in body size dentists and nurses may need to stand up or use a step to treat patients. Staff should receive training and advice from moving and handling teams and be rotated on a regular basis. Appropriate risk assessment processes should be completed prior to delivery of care. If an emergency occurs and a bariatric patient is unwell it is important to state when contacting the emergency ambulance service that the patient requires a bariatric ambulance, as bariatric ambulance facilities vary from region to region.

Dental considerations

As the prevalence of obesity within the general population increases, there will be an increasing demand on dental services to meet the needs of those overweight and obese individuals. Dentists need to be aware of the implications that this will pose, including associated dental issues, and the considerations to be taken when planning and delivering treatment in this patient group.⁹ Access and visibility for examination and treatment may be challenging due to the physical size of the patient, and enlarged soft tissues such as tongues and cheeks. This may also pose a challenge in identifying and palpating anatomical landmarks such as when administrating inferior dental nerve blocks, or intravenous cannulation.⁸ Difficulties may arise in treating these patients in the supine position due to excessive weight around the neck and trunk compromising the airway.

There is extensive reference within the literature to the links between obesity and dental disease, including dental decay and periodontal disease.^10,11 It should be noted that both obesity and dental caries are multifactorial diseases and are correlated to the individual's dietary habits; those exposed to a high frequency and amount of sugar containing foods can be predisposed to both. Dentists can play a role in identifying detrimental dietary habits, and emphasis should be placed on diet assessment and modification, and caries prevention methods. It has been theorized that the chronic systemic inflammation present in obesity may increase a person's susceptibility to periodontal disease.¹⁰ Efforts should be made to signpost these individuals to relevant preventative oral health practice to ensure any other periodontal disease risk factors are identified and eliminated.

Evidence suggests that the prevalence of tooth loss is increasing in overweight and obese populations.¹² This may result in accommodating these individuals to a shortened dental arch, or provision of removable or fixed prosthetic replacement. Patients' motivation for replacement options should be assessed and risk factors that may precipitate further tooth loss addressed before provision of definitive replacement. Following bariatric surgery or other weight loss methods, patients may find that existing prostheses become ill-fitting due to changes in facial soft tissue profile and musculature.

In those individuals who have undergone bariatric surgery, a common side effect is reflux and vomiting, resulting in high levels of acid in the oral cavity throughout the day, potentially predisposing to dental erosion and tooth surface loss.^13,14,15 They may present with issues of dental sensitivity or pain, impaired occlusal or masticatory function, or aesthetic concerns, warranting more extensive restorative treatment planning to conform or reorganize the occlusion, including composite augmentation, removable prostheses or crown and bridgework. This may place an increased demand on operative time and skill of the clinician. Following bariatric surgery, patients often develop altered dietary habits, habituating to frequent small meals or ‘grazing’ throughout the day. These changes can result in rapid deterioration of a dentition, with patients requiring frequent and often extensive treatment.¹⁶

Psychosocial factors

There are often multiple interacting psychosocial factors involved with this group of patients. These may range from mental health problems to anxiety neuroses and eating disorders, which all may result in neglected teeth, dental avoidance, appearance concerns managed with avoidance strategies, and social isolation.

Medical considerations

Reflecting the multifactorial nature of obesity, the condition has substantial systemic and psychological impacts. Though systemic factors are a significant concern to healthcare professionals, the impact of psychological factors must be considered. Conditions such as depression, other mood disorders and a reduced quality of life are common in obesity and can either precede or result from significant weight gain and cannot be ignored when caring for patients holistically.¹⁷

Alongside the dental and psychological implications, obesity has a significant physiological impact. An excess of weight affects multiple organ systems directly and indirectly leading to a strong association with multiple systemic diseases including type 2 diabetes, multiple cancers, cardiac disease, asthma, gallbladder disease and osteoarthritis.¹⁸ The impact on cardiovascular and respiratory systems is of particular concern. To maintain sufficient circulation, the demands on the heart are substantially increased. Combined with increased oxygen demands and a decrease in relative lung capacity, cardio-respiratory compromise can affect patient's exercise tolerance and mobility, which can lead to further fat accumulation.¹⁹ The strain on the cardio-respiratory system means that hypertension, heart failure and breathlessness are highly prevalent in patients with obesity. Specifically in the upper airway, obstructive sleep apnoea is a concern for dental teams and is correlated with obesity.¹⁹ In this syndrome, airway obstruction, either complete or partial can occur during sleep due to decreased upper airway tone which can cause collapsing of the pharynx. This condition interrupts patient's sleep and is associated with further comorbidities or worsening of comorbidities that may already be present in a person with obesity such as hypertension, ischaemic heart disease and cerebrovascular disease.²⁰

Type 2 diabetes is also highly prevalent in patients with obesity, arising from initial hyperinsulinaemia and subsequent insulin resistance.²¹ With increasing obesity, diabetes becomes more prevalent, but also more challenging to manage. In diabetes, microvascular inflammation can lead to kidney disease, visual impairment from retinopathy or peripheral neuropathies, while macrovascular inflammation can further increase a patient's risk of stroke, ischaemic heart disease or peripheral vascular disease.²² Each of these conditions or their combination can further impact a patient's ability to access services and mobilize to dental chairs, or indeed the medical suitability of dental treatment.

As a consequence of these factors and a variety of complex interacting phenomena, when a BMI exceeds 35 kg/m², the risk of all-cause mortality is significantly increased.⁵ Though many conditions will be declared on a medical history form, there is a potential for patients to be experiencing significant systemic disease which is either subclinical or currently undiagnosed, potentially due to the limited ability to attend other healthcare settings. The impact of obesity on specific health conditions is comprehensively detailed in relevant literature^8,9,23 yet warrants careful consideration and individual patient risk-assessment due to the elevated risk of medical emergencies or complications affecting delivery of dental care. Comprehensive medical history-taking and liaison with physicians becomes increasingly crucial as both the number and severity of comorbidities increases.

Sedation

Each of the aforementioned medical problems associated with obesity, and their combination, can have significant impacts on the suitability and safety of conscious sedation or general anaesthesia. For patients with dental anxiety, or other factors whereby sedation is indicated, a comprehensive risk assessment is essential to select the most suitable approach for each patient. Treatment under local anaesthetic remains the first choice for most patients. Inhalation sedation, is a very useful facilitator for anxious patients, and remains safe for the majority of overweight or obese patients because it is used in conjunction with oxygen delivery for brief periods, and does not carry the risk of the respiratory depression associated with intravenous sedation agents.²⁴

For intravenous sedation, multiple factors can affect safety of care delivery and patients with an ASA III status are unsuitable for intravenous sedation in a primary care setting.²⁵ Although a BMI has to exceed 40 kg/m² for a patient to be given an ASA 3 status,²⁶ many practitioners agree that those with a BMI exceeding 35 kg/m² are at sufficient risk from IV sedation to warrant referral to hospital or specialist services. Cannulation can be challenging where there is an excess of adipose tissue, and once drugs are administered, the pharmacokinetics of commonly used drugs can be significantly altered due to the distribution of certain medications into tissue spaces.^27,28 The respiratory depression associated with sedation agents can be more profound in those with already compromised respiratory and cardiovascular systems compounded by the increased weight resting on the chest of a reclined patient with excess adipose tissue.^28,29 Alongside the potential for superimposed obstructive sleep apnoea leading to apnoeic episodes, de-saturation during procedural sedation is far more likely in patients with obesity and can result in life-threatening scenarios. The STOP-BANG screening tool¹⁹ can be useful to detect sleep apnoea yet even bariatric patients at lower risk of this condition are generally poor candidates for treatment with intravenous sedation.

General anaesthesia

General anaesthetic for bariatric patients carries with it unique and elevated risks. When general anaesthesia is used, some of the risks of intravenous sedation are mitigated through intubation, which allows security and control of a patient's airway. In addition, a wider range of anaesthetic agents can be carefully selected by anaesthetic teams to account for pharmacodynamics and pharmacokinetic differences in bariatric patients.^27,28 Obesity is so impactful on anaesthesia provision that a dedicated society for bariatric anaesthetics has been formed; this organization makes a range of recommendations to improve the security of anaesthesia for patients with obesity, such as alteration of drug doses, additional monitoring aids and altered equipment.²⁷

Despite adaptations in anaesthesia provision, patients with obesity can experience delayed recovery, and are at greater risk of peri-operative morbidities, such as venous thromboembolism³⁰ and cardiorespiratory compromise. Inpatient units are generally preferable to day-stay anaesthetic facilities for patients with a BMI over 40 kg/m² or for those with a greater degree of systemic compromise. This ensures that any complications arising from general anaesthesia can be managed over a longer period if required. Patients with sleep apnoea who have a CPAP (continual positive airway pressure) machine should be asked to bring these machines with them when an anaesthetic is anticipated. Wherever possible, local anaesthetic is the preferred modality of treatment. Every effort should be made to avoid the need to treat patients with obesity using general anaesthesia.

Conclusion

The delivery of high-quality, safe dental care to patients with bariatric needs can be challenging. Success depends on the rigorous assessment of the specific practical needs of the patient, having the appropriate facilities and supporting framework to manage these needs, and then a good understanding of the often closely related medical and dental issues that interplay to impact on dental care. It is acknowledged that the problem of obesity is increasing, and the dental community must be cognisant of how we can facilitate care by having robust referral pathways to sites that have the appropriate staff and resources that can plan to manage the workload. Workforce planning, financial investment and education must be at the forefront of this.