Smell, Taste, Salivary Flow, and Oral Health in Patient Receiving Dialysis: A Before and After Study.

Studies show that the change of smell and taste, also dry mouth are the most common symptoms in end stage renal disease patients, the accumulation of uremic toxins would damage the intrinsinc antioxidant systems of the olfactory epithelium and olfactory bulb, which leads to smell dysfunction compared to healthy group. Previous studies show different results about if getting rid of uremic toxins would help improve smell, even if they say olfactory identification is improved after hemodialysis episode, but there's no short term reliability of Sniffin'sticks to prove the credibility of the findings. Reduction of the whole saliva and unstimulated salivary flow rate cause dry mouth, also change oral environment, which makes dental plaque easily attach to teeth. And the accumulation of uremic in oral cavity causes oral odor, plus lack of zinc iron and reduction of saliva would affect the tastants transferred to its receptors which leads to taste dysfunction. Besides, when the patients has olfactory dysfunction, the taste will be affected as well, plus the accumulation of uremic toxin in the oral cavity also stops the conjunction of smell and taste receptors which affects taste. To understand smell, taste and oral condition in end stage renal disease patients, and due to there's no short term reliability of Sniffin'sticks, plus it's expensive and time-consuming to implement the taste assessment tool. Thus the main purpose of this study is: 1. To investigate smell and taste function, salivary secretion, oral condition, plaque index and dry mouth in end stage renal disease patients who haven't been under hemodialysis. 2. To investigate the short term reliability of Sniffin'sticks, the measuring tool of olfactory with 3-4 hours interval. 3. To investigate if Taste and Smell Survey could be the tool which detects abnormality of taste 4. To investigate the change of smell, taste and salivary secretion within 24 hours after the first episode of hemodialysis.