PMT, PNBD and PD measurement on the second molar tooth level image.The oral surface of the palatal mucosa is indicated by the yellow line, PMT measurement lines were perpendicular to this surface. Distances to CEJ according to line colors: orange: two mm, green: four mm, white: six mm, blue: eight mm. Yellow curved line indicates the oral surface of the palatal mucosa. Purple line is palatal depth and red line is measurement of PNBD which shows the distance between CEJ and palatal groove. (PMT, Palatal mucosa thickness; PNBD, Palatal neurovascular bundle; PD, Palatal depth; CEJ, Cemento-enamel junction).