**2.5 Oral mucosal changes**

More recent studies have pointed out that extraesophageal symptoms of GERD are acidic lesions of the oral mucosa. These lesions are caused by direct acid and pepsin exposure, or acidic vapor contact in the oral cavity. GERD was reported to be associated with microscopic alterations in the palatal mucosa, such as epithelial atrophy, deepening of epithelial crests in connective tissue and a higher prevalence of fibroblasts [18]. Mucosal changes are quite common and not pathognomonic and specific of patients with gastroesophageal or esophagopharyngeal reflux, but erythema of the soft palate and uvula, epithelial atrophy, xerostomia and glositis are quite common in GERD patients. Some authors pointed out the presence of aphtoid lesions, hoarseness, chronic periodontitis, dry oral mucosa with a keratotic appearance of the gingival tissues and the presence of burning mouth. In addition, persons with GERD may complain of a sour or acidic taste, impaired taste (dysgeusia), an oral burning sensation and water brash (flooding of the mouth with saliva in response to an esophageal reflux stimulus) [19]. Adequate mucin-rich salivary secretions coat all of the internal anatomical surfaces and are essential for the protection of the oropharyngeal and esophageal mucosa and the teeth from chemical, thermal, mechanical and microbial damage. Saliva also facilitates efficient swallowing and speech. Some studies have found a significant association between gastroesophageal reflux and hyposalivation. On the other hand, proton pump inhibitors can cause hyposalivation. Hyposalivation may result in xerostomia, impaired mastication and swallowing, painful mouth, cracked lips and angular cheilitis [20].
