A digital technique for recording and assessing mouth opening based on intraoral scanning.

To avoid intraoperative instrument obstruction, the accurate evaluation of a patient with limited mouth opening is essential as a critical step in preoperative planning for guided implant surgery. This article presents a digital technique based on intraoral scanning for recording and evaluating the mouth opening at implant surgical sites. Dentition data were acquired by using an intraoral scanner, and the maxillomandibular positional relationship at maximal mouth opening was recorded with a combination of polyvinyl siloxane putty impression material and occlusal registration silicone material. After digitization and data alignment, 3-dimensional maxillary and mandibular dentition data at maximal mouth opening were obtained. Virtual instruments with dimensions corresponding to the actual handpiece and drill were established in the software program to simulate instrument positioning. This technique enabled digital reconstruction of the maxillomandibular relationship at maximal mouth opening and allowed instrument-specific evaluation of mouth opening adequacy during implant planning.