**6. Conclusions**

of radiotherapy are mucositis, xerostomia, dysphagia, hoarseness, erythema and desquama‐ tion of the skin (dermatitis). Other late complications that frequently are observed in radio‐ therapy post-treatment are dental decay, trismus, hypogeusia, subcutaneous fibrosis, thyroid dysfunction, esophageal stenosis, hoarseness, damage to the middle or inner ear, and osteor‐ adionecrosis (infection in a hypovascularized tissue with consequent tissue destruction). These post-radiotherapy sequelae are dependent on radiation field, radiation dose, use of antixerostomic medication, and post-radiotherapy time. In xerostomic patients, irreversible damage can occur to the salivary glands, resulting in dramatic hyposalivation and increases in oral and systemic infections. Moreover, oral mucositis induced by radiation therapy frequently occurs, leading to painful oral ulcerations and local and systemic infection. In patients treated with high dose radiation, swallowing can be affected several years after treatment due to a series of complications such as fixation of the hyolaryngeal complex, reduced range of tongue motion, reduced glottic closure, and cricopharyngeal relaxation, resulting in the potential for aspiration. Irradiated patients have longer oral transit times,

increased pharyngeal residue, and reduced cricopharyngeal opening times [106].

**5. The role of the dentist in an interdisciplinary effort to manage**

Oropharyngeal dysphagia arises as a result of so many types of endogenous or exogenous injuries that affect, isolated or combined, the salivation, chewing, and swallowing mecha‐ nisms. Injuries in these mechanisms usually impair the physical and mental health and quality of life of individuals. Undoubtedly, successful management requires an interdisciplinary collaboration among health professionals, which need to promote an accurate diagnostic workup, promote effective therapeutic strategies, and formulate an adequate management strategy of dysphagic patients in cases where cure of that condition is not currently possible. The dentist is a health professional that clinically evaluates the oral health of patients at frequent intervals. However, in most curriculums of dental schools, very little is presented and discussed about chewing and swallowing disturbances regarding the diagnosis, management, and treatment of these conditions. Moreover, nor is it strongly discussed about salivary gland

and food aspiration [106-108].

30 Seminars in Dysphagia

**oropharyngeal dysphagia**

Concurrent chemoradiation was introduced to improve prognosis of UADTC patients by increase the tumor cell killing with chemotherapy, which also acts as a radiosensitizer. However, although inoperable tumors showed a better prognosis, the toxicity of the two modalities combined resulted in more significant side-effects. Various side-effects like nausea, vomiting, mucositis induced by chemotherapy, dysphagia, neutropenia, and generalized weakness might occur. The anti-metabolites such as methotrexate and 5-fluorouracil are the cytotoxic agents most commonly associated with oropharyngeal and esophageal dysphagia. Chemotherapeutic agents can impact the ability of UADTC patients to swallow. Severe dysfunction of the base of the tongue, larynx and pharyngeal muscles are observed after chemoradiation, leading to stasis of the bolus, vallecular residue, dysmotility of the epiglottis,

> The different parts of the oral cavity and oropharynx are made up of several cell types of tissues (nerves, fibrovascular tissues, cartilaginous tissues, lining and salivary gland epithelium, and

smooth and striated muscles) along withenamel and dentin tissues of the teeth and the supporting bones. The morphophysiology of the oral cavity and oropharynx components is responsible for preservation and maintenance of oral health which contributes to systemic health and a better quality of life to individuals. These components are parts of the body that are highly accessible, sensitive to the action of environmental factors and, at the same time, are able to reflect changes occurring internally in the body. Oropharyngeal dysphagia represents a neuromuscular disorder which characterizes individuals with a difficulty in swallowing. That disorder may result from an accumulation of many factors caused by both endogenous and exogenous etiologic agents which compromise, directly or indirectly, mechanisms of salivation, chewing, and swallowing. The dentist is the health professional that clinically evaluates the oral health conditions of individuals regularly. That health professional must be considered as an integral component of the multidisciplinary health team in order to perform proper educational and preventive approaches, management, and therapeutical actions that might restore oral health to their patients.
