Conflict of interest statement: C. A. Migliorati has acted as a paid consultant for Colgate-Palmolive. C. Madrid received an indemnity as a member of the Novartis Expert Board on bisphosphonates osteonecrosis.
Corresponding author and reprint requests: C. A. Migliorati, NSU College of Dental Medicine, 3200 S. University Drive, Fort Lauderdale, FL 33328, USA E-mail: firstname.lastname@example.org
The focus of this review is to highlight the need for improved communication between medical and dental professionals in order to deliver more effective care to patients. The need for communication is increasingly required to capitalise on recent advances in the biological sciences and in medicine for the management of patients with chronic diseases. Improvements in longevity have resulted in populations with increasing special oral-care needs, including those who have cancer of the head and neck, those who are immunocompromised due to HIV/AIDS, advanced age, residence in long-term care facilities or the presence of life-long conditions, and those who are receiving long-term prescription medications for chronic conditions (e.g., anti-hypertensives, anticoagulants, immunosuppressants, antidepressants). These medications can cause adverse reactions in the oral cavity, such as xerostomia and ulceration. Patients with xerostomia are at increased risk of tooth decay, periodontal disease and infection. The ideal management of such individuals should involve the collaborative efforts of physicians, nurses, dentists and dental hygienists, thus optimising treatment and minimising secondary complications deriving from the oral cavity.
The oral cavity provides a variety of surfaces for bacterial colonisation, and each environment supports a characteristic bacterial population. The composition and quantity of the bacterial population on mucosal and tooth surfaces are influenced by many factors, such as the integrity of the soft-tissues, oral hygiene, saliva, diet, and the host's immune and inflammatory responses. Numerous examples illustrate the devastating effect that immunosuppression, radiation therapy and medications can have on the oral tissues. Systemic spread of oral microbes and spread following immune responses may have deleterious consequences for systemic diseases and their treatment. There is also increasing evidence that periodontal disease may be associated with an increased risk of cardiovascular disease, premature, low-birth-weight babies and respiratory diseases. As the life-expectancy of the population increases, in part due to advances in medical science, it is highly recommended that the medical and dental professions integrate their care of patients.
Undiagnosed medical conditions
In 2005, Glick and Greenberg  evaluated the possibility of dentists identifying patients with risk-factors for cardiovascular disease prior to the appearance of clinical signs and symptoms. They examined surveys that had evaluated the health and nutrition of Americans, aged 40–85 years, between the years 1999 and 2000, and compared the results with data from 2001–2002. They found that 18% of the men presented with a large number of risk-factors for coronary artery disease. Although still controversial, it has been suggested that panoramic radiographs of the jaws can capture images of calcified carotid atheromas in asymptomatic patients receiving routine dental care . Individuals visit the dentist more frequently than they visit a medical practitioner, and consequently the dentist is in a privileged position to identify individuals at risk for cardiovascular diseases, cancer, diabetes and hypertension, and thus has an important role in the prevention of infective endocarditis [3–5]. Therefore, collaborations between these healthcare professionals would result in the early referral of patients, leading to early diagnosis and prompt management of emerging medical conditions.
Oral health and cancer therapy
All types of cancer treatment may predispose to oral complications, and it is important that patients undergoing chemotherapy, radiation therapy (RT) and bone marrow transplantation receive advice from a trained dental professional prior to treatment. Such treatments are frequently associated with oral complications that impact on the quality of life and the cost of care. Dry mouth, gingival bleeding, mucositis and ulceration all contribute to the discomfort of patients and interfere with daily activities such as eating and talking. Oral complications may delay cancer treatment and may be dose-limiting, thus influencing the outcome. These issues have prompted the publication of guidelines for the prevention and management of oral complications associated with the treatment of cancer (http://www.cancer.gov/cancertopics/pdq/supportivecare/oralcomplications/HealthProfessional/page 3).
For example, patients diagnosed with head and neck cancers who are scheduled for RT should be referred to a dentist for assessment. Unfortunately, in our experience, oncologists rarely forward information regarding the type of tumour, its location, the amount and timing of radiation and the region of the head and neck to be irradiated. Knowledge of the type of technique chosen for radiotherapy (conventional, conformational, intensity-modulated radiotherapy or tomotherapy) can help the dentist to anticipate complications involving sensitive structures such as salivary glands. This information is vital for the design of a preventive dental programme [6,7]. However, general dentists are usually not fully trained to evaluate oncology patients with respect to potential head and neck complications anticipated during RT for cancer of the head and neck. This lack of communication and training often results in inadequate preparation of the oral cavity. Consequently, secondary complications, which include infections with opportunistic organisms and the development of osteoradionecrosis, may occur if untreated oral conditions require subsequent manipulations of irradiated areas .
Collaboration between an oral medicine specialist and the oncology team can significantly benefit patients, and should include an initial evaluation prior to treatment and regular follow-up during the operative and post-operative periods. In the pre-operative phase, patients should be advised of the importance and benefits of maintaining good oral hygiene, including a high-fluoride regimen for caries prevention, and should receive dietary advice . During the period of therapy, the oral cavity should be inspected frequently. The development of xerostomia and oral mucositis predisposes the patient to extensive ulceration and injury of the mucosal tissues, and increases the opportunity for oral bacteria to gain access to the bloodstream and cause infections at distant sites . The course of mucositis parallels that of bone marrow suppression induced by cancer therapy and increases the risk of oral infection due to opportunistic microorganisms of bacterial, viral and fungal origin [10,11]. A prompt diagnosis of these complications is vital for oral health, continuation of the scheduled cancer therapy, and the overall success of the treatment (Fig. 1).
Bisphosphonate-associated osteonecrosis (bon)
Bisphosphonate-associated osteonecrosis of the maxilla and mandible represents the most recent example of the need for collaboration between medical and dental professionals. This recently described condition should lead to the building of multidisciplinary medical teams including oncologists, specialists in bone diseases, maxillo-facial surgeons, primary care physicians and specialists in oral medicine . Effects in the mouth represent one of the first long-term complications observed with bisphosphonate therapy . Bisphosphonates are osteoclast inhibitors used in the treatment of patients with osteopenia, osteoporosis, hypercalcaemia of malignancy, Paget's disease of bone, and cancer patients with bone metastasis. This condition (BON) is defined as the unexpected development of necrotic bone in the oral cavity of patients who are being treated with a bisphosphonate and who have not received RT to the head and neck (Fig. 2). When the affected area persists for 6–8 weeks after proper dental care is provided to the patient, the diagnosis of BON can be confirmed . On the basis of the cases currently reported, the treatment of cancer patients with nitrogen containing intravenous bisphosphonate seems to present the highest risk for this oral complication [13–16]. Other risk-factors that have been implicated include the presence of infection, recent dental extraction and any oral surgical procedures where bone exposure and/or manipulation occur. It has also been suggested that the duration of drug exposure and the number of bisphosphonate treatments are important risk-factors for BON. Current guidelines, which are based on expert opinion, strongly recommend that patients should be referred for oral and dental evaluation prior to bisphosphonate therapy, thus providing the dental professional with the opportunity to diagnose and treat any existing dental disease and recommend an effective oral hygiene programme .
Infections are commonly reported in almost all cases of exposed necrotic bone associated with bisphosphonate therapy. The flora recovered from the sites contains both Gram-positive and Gram-negative bacteria. Specific therapy with antibiotics following culture and antibiogram does not necessarily control the infection or stimulate healing of the necrotic area. Several reports describe the presence of Actinomyces spp. and suggest a possible involvement of this organism in the aetiology of BON .
Information about the nature, duration and detailed indications of the treatment is needed. Long-term bisphosphonate therapy calls for a reduction in and significant alteration of dental treatment plans in order to avoid surgical manipulations that favour bone exposition, e.g., open periodontal curettage and implant placement . The dentist will need to be aware of the life-expectancy of the patient according to the oncologist, in order to adjust the objectives of the dental programme to the patient's individual risk as related to the duration of drug exposure . Patients can be educated and encouraged to report to either the physician or the dentist when oral complications are observed.
The development of optimal management strategies for patients with BON, including discontinuation of therapy, is dependent on the collaborative efforts of physicians, maxillo-facial surgeons and dentists. However, since bisphosphonates are prescribed for medical reasons, it is the physician who should make treatment decisions, including discontinuation. Careful assessment is required prior to discontinuation of bisphosphonate therapy, as discontinuation can lead to severe complications for some patients, with additional risks noted among those with osteoporosis. For example, hip fracture and high mortality have been reported after cessation of an oral bisphosphonate among such patients. The reported incidence of death 1 year after hip fracture is 20–25%. These factors highlight the need for consultations between the dentist and physician for appropriate alternative treatments .
Oral health in intensive care units
How can oral care be implemented in an environment where the main objective is to preserve the life of the patient? Effective oral hygiene keeps the mouth functional and comfortable and, more importantly, reduces the risk of local and systemic infection . Nurses often lack training in the recognition of oral complications and the optimal techniques for oral care . In fact, it is very difficult to maintain oral care when the patient has an endotracheal tube that, if displaced, can result in a life-threatening situation . Within 48–72 h, the oropharyngeal flora, which is usually dominated by Gram-positive bacteria, mainly streptococci, shifts to a more pathogenic aerobic Gram-negative flora. When an endotracheal tube is in place, the open-mouth position of the patient results in xerostomia, an environment ideal for bacterial colonisation and proliferation (Fig. 3). In 45% of critically ill patients, and 75–100% of patients receiving ventilation, the upper respiratory tract is colonised by Gram-negative bacteria. The average incidence of ventilator-associated pneumonia is 47% of infections in patients in intensive care units, with a mortality of 24–76%[22,23]. A high percentage of patients with ventilator-associated pneumonia have a Gram-negative flora (including Pseudomonas aeruginosa, Enterobacteriaceae, Haemophilus spp. and Acinetobacter spp.) and Gram-positive flora (including Staphylococcus aureus and Streptococcus spp., including Streptococcus pneumoniae) . It is important to maintain an effective programme of oral hygiene, and studies have demonstrated that chlorhexidine reduces the incidence of ventilator-associated pneumonia and the colonisation of the oropharynx by pathogenic flora . Several other oral hygiene programmes have been tested, with the dual objective of improving oral health and patient comfort and decreasing the risk of local and systemic complications. Guidelines for nurses, issued by the CDC, stress the importance of oral hygiene in intensive care unit patients . However, recent surveys in the USA and Europe demonstrate that current practices are far from effective, and training of medical/dental professionals in this field of medicine is essential [25–27].
Oral health in long-term-care facilities
The increasing elderly population  imposes demands on medical care, with factors such as frailty and loss of mobility making it difficult for these individuals to lead independent lives. Institutionalised care in long-term-care facilities and nursing homes is becoming commonplace; such facilities are typically supervised by physicians and nurses, and rarely are dental professionals involved. Consequently, oral care is provided by non-dental personnel who have little or no training. Poor oral health in the elderly population contributes to increased morbidity and decreased quality of life .
Many of the prescription medications used by elderly individuals are associated with the development of dry mouth, which increases the risk of colonisation of the oral mucosa by pathogenic microorganisms that can cause both local and systemic infections [28,29]. Deteriorating general health and the long-term use of antibiotics in nursing home residents lead to an increased incidence of opportunistic infections such as pneumonia, a significant cause of morbidity and mortality in the elderly . The aspiration of oral bacteria by institutionalised elderly individuals is a risk-factor for hospital-acquired pneumonia . Several factors predispose this population to changes in the oral environment. These factors include poor oral hygiene, reduced dexterity, poor compliance, and a neglected dentition, the last of these making it difficult for individuals to chew and swallow with reasonable efficacy. Professionally delivered oral care could improve the oral and general health of this population. Oral hygiene performed professionally, even once a week, can significantly reduce the incidence of aspiration pneumonia, the most common reason for acute medical care in this population .
An emerging concern in nursing homes is malnutrition, and a recent report describes the role of oral health professionals in enhancing the effects of nutritional interventions . Oral functional training for the maintenance and improvement of feeding function enhances nutrition among patients on a high-calorie or high-protein diet. Thus, synergy between medical, dental and nursing professionals would help to prevent important medical complications with a simple improvement in the oral hygiene programmes in long-term-care facilities and nursing homes.
This brief review has given some examples to highlight the importance of collaboration between the medical and dental professions in order to improve both oral and systemic health. Other examples of medical conditions that would benefit from such a collaboration include human immunodeficiency virus infection and AIDS, diabetes, rheumatoid arthritis, Sjögren's syndrome and the status after organ transplantation.
Ongoing review of the curricula of medical and dental schools should lead to better integration of the professions. Medical, dental and nursing students should have the opportunity to integrate as part of their training . This need has already been recognised in some US and European medical schools, with the introduction of oral health curricula in undergraduate medical training . Another need is the development of a strong specialty in oral medicine that would educate a professional capable of serving as a partner to physicians . Such partnerships will contribute to the optimal management of patients who are ill as a result of the emerging relationship between systemic and oral conditions . The outcomes of these collaborations include decreased morbidity and mortality, and improved quality of life for ageing populations around the world . Education, highlighting the importance of communications between healthcare professionals, will lead to better treatment options and enhance the level of care .