[No Title Available]

Abstract

Radiotherapy, alone or associated with surgery or chemotherapy, produces a significant increase in cure rates for many malignancies of the head and neck region. However, high doses of radiation in large areas, including the oral mucosa, may result in several undesired reactions that manifest during or after the completion of therapy. The multidisciplinary management is the best alternative to minimize or even prevent such reactions, and the dentist has a fundamental role in this context. This paper reviews the literature related to the main oral sequelae from head and neck radiotherapy and establishes clinical oral management protocol for these irradiated patients.

Salivary gland stem cells: A review of development, regeneration and cancer

“…Although their gross anatomy can vary dramatically across species, the complex serous-mucous liquid produced (saliva) plays an important and often essential role in survival through its impact on diet, for example, mice die within days after major gland removal. Although functional salivary glands are not required for human survival, SG dysfunction that arises from genetic anomalies (e.g., LADD or ASLG syndromes), or damage from surgery, therapeutic radiation for head and neck cancer (Frank et al , 1965; Valdez et al , 1993), or autoimmune diseases such as Sjögren’s syndrome (Azuma et al , 1997; Patel and Shahane, 2014; Stewart et al , 2008) impairs oral health, resulting in a myriad of symptoms including mastication and swallowing difficulties (Dusek et al , 1996; Hamlet et al , 1997; Tolentino Ede et al , 2011), speech impairment (Rhodus et al , 1995), mucosal alterations, oral infection (Azizi and Rezaei, 2009; Brown et al , 1975; Davies et al , 2006) and accelerated tooth decay (Lu et al , 2014). Despite these detrimental and life-long effects, current therapies are limited to secretagogues and artificial saliva, with no long-term solutions to restore salivary gland function.…”

Effects of radiotherapy on oral cavity tissues

“…Dry mouth (xerostomy) occurs as a result of salivary glands damage under the action of ionizing radiation. Oedema of salivary glands happens in the first hours after the beginning of radiation [7], resulting in decreased salivation and increased viscosity of saliva, which becomes thick and sticky. The disorder of salivary gland vascularization is due to fibrotic changes in the blood vessel wall, leading to atrophy and necrosis of glandular cells.…”

“…Decalcification of the tooth enamel is caused by changes in the chemical composition of the saliva and increased number of cariogenic bacteria in the oral cavity [7], which, in addition to dry mouth and decrease in pH of the oral cavity, favours caries formation. A special feature of radiation caries is the absence of pain, despite rapid progression and extensive loss of solid substance due to demineralization process of affected teeth [8].…”

“…During radiotherapy using high doses of radiation, development of fibrotic changes in chewing muscles (m. masseter) occurs as well as the reduction of flexibility and extension in the region of temporomandibular joint, with the presence of mandibular hypomobility. These changes usually occur within few months after completion of radiotherapy, and can be that severe that patient can open mouth less than 2 cm, which significantly affects speech and food intake [7]. Sometimes, complete stiffness or ankylosis of temporomandibular joint may occur.…”

“…Suvoća usta (kserostomija) nastaje kao posledica oštećenja pljuvačnih žlezda pod dejstvom jonizujućeg zračenja. Edem pljuvačnih žlezda počinje već u prvim satima nakon početka zračenja [7], zbog čega dolazi do smanjenja lučenja pljuvačke, koja postaje gusta i lepljiva, i povećanja njenog viskoziteta. Poremećaj vaskularizacije pljuvačnih žlezda nastaje usled fibroznih promena u zidu krvnih sudova, što dovodi do atrofije i nekroze žlezdanih ćelija.…”