The software draws the center and the borders of the denture base by considering the labial frenulum and the buccal frenulum.
A proposal will be created automatically. You can adapt this subsequently. You have to place the base boundary exactly in the oral vestibule (maxillary and mandibular vestibules).
The proposal must take into consideration the area of the triganon and the tuberculae and enclose them. Otherwise the base is too small.
For functional impressions the base border is suggested to be the model border. For first impressions the border is calculated to be located in the mucolabial fold.