Frequency of Periodontal Disease in Head and Neck Cancer Patients After Radiation Therapy: a Cross Sectional Study

Introduction Cancer accounts for 12% of global deaths and poses a significant health challenge, with over 10 million new cases and 6 million fatalities annually worldwide [1]. Among them, head and neck neoplasia (HNN) is a major form of cancer in India, accounting for 23% of all cancers in males and 6% in females; Depending upon the sub-site of origin and the clinical extent of the disease the 5 -year survival varies from 20% to 90% [2]. The three most common modalities used in head and neck cancer treatment are surgical resection, radiotherapy and chemotherapy, either used singly or in combination. While these modalities are effective in eliminating the tumor, they also adversely affect the normal head and neck structures surrounding the tumor. Radiation therapy has cytotoxic effects on both normal cells and malignant cells. Direct damage to the oral structures (soft and hard tissue) commonly occurs from radio- and chemotherapy, and indirect damage may also occur from systemic toxicity. These oral complications may arise during and following cancer treatment and are commonly grouped into two broad categories: acute and chronic [3].

The reported acute oral complications are mucositis, xerostomia, dysphagia, dysgeusia, and opportunistic infections, and chronic complications such as trismus, irradiation caries, osteoradionecrosis, and changes in periodontal attachment. The long-term effects comprise alteration in vascularity of soft tissue and bone, salivary gland damage, reduction in cellularity of connective tissue, and risk of increased collagen synthesis which results in fibrosis [4]. Radiation treatment induces obliterative end- arteritis that results in soft tissue ischemia and fibrosis while the irradiated bone become hypo vascular and hypoxic [5]. The periodontium is sensitive to the effect of radiation at high doses. Diminished vascularity and cellularity of the periodontal ligament membrane with widening of periodontal space, thickening, rupturing, and disorientation of Sharpey s fibers have been reported [6].

The direct and indirect effect of high-dose radiotherapy (RT) on the periodontium results in greater risk of periodontal attachment loss and tooth loss and greater risk for the development of osteoradionecrosis[7]. The extensive periodontal destruction may occur in the absence of good oral hygiene. Periodontitis in patients scheduled for head and neck radiotherapy results in acute and chronic complications such as osteoradionecrosis. Maintenance of good oral hygiene in patients undergoing radiotherapy may reduce morbidity of the known oral and periodontal side effects [8].

Patient stated to receive the head and neck radiation therapy need dental consultation at the earliest possible time. Pre-irradiation treatment depends on patient prognosis, compliance, and residual dentition, in addition to fields, ports, dose and immediacy of radiotherapy. Diseases of teeth and supporting structures are a worrying finding in a patient about to undergo tumoricidal radiotherapy for a malignant condition in the maxillofacial region because oral pain and infection are common and a potentially serious sequence to radiotherapy for head and neck tumors in patients with healthy mouth. The loss of integrity of the gingival crevicular tissues, as a result of periodontitis and radiotherapy induced thinning of these tissues together with xerostomia, mucositis, altered diet, and poor oral hygiene that often follow high-dose radiotherapy to the jaws, can create oral problems that affect the quality of life, which can cause interruption to cancer therapy [9].

The periodontal blood vessels are affected by radiation leading to widening of periodontal ligament space and destruction of bony trabeculae which may result in increased risk of periodontal disease and altered healing with diminished capacity for bone remodeling and repair [10]. Llory et al., showed a radiation-induced downshift of periopathogens [11]. Markitziu et al. [12] and Leung et al. [13] reported that due to radiation induced hypo-salivation and a concomitant increase in plaque accumulation and shift in oral micro flora the risk of periodontal infection is also increased. Shwarze et al., found a greater number of shallow periodontal pockets in radiated patients [14]. The reduced probing pocket depth does not indicate the histological pocket depth since the probe generally penetrates coronal level of junctional epithelium due to inflammation of underlying connective tissue or may be due to disparity between probing technique, probing force, or angle of insertion of the probe [8].