Fig. 3

Registration of a maxillary models, b mandibular models, c corresponding heat maps by Geomagic software. Three points on the medial ends of third and second rugae areas in the maxillary arch and three points on the mucogingival junction (MGJ) between first premolar and second premolar, second premolar and first molar, first molar and second molar were selected as reference landmarks, followed by a global and fine regional surface registration