The association of acidic reflux above the upper oesophageal sphincter with palatal tooth wear.

This case-controlled clinical study, conducted at a secondary care unit, compared pH measurement at 2 cm above the upper oesophageal sphincter (UOS) in 31 patients complaining of extra-oesophageal symptoms of reflux to 7 control subjects. Twenty-four-hour ambulatory pH measurements were recorded and analysed at 5 cm above the lower oesophageal sphincter (LOS) and 2 cm above the UOS. In reflux patients the proportion of supine time when pH at 5 cm above the LOS was <4 was significantly greater than in controls. The proportion of time when pH at 2 cm above the UOS was <5.5 was also significantly greater in patients than in controls. Palatal tooth wear observed in the patient group correlated with acid reflux at night. In this group of patients presenting with symptoms of reflux, gastric acid passed through the upper oesophageal sphincter and increased the potential for erosion.