Reconstruction-Based Digital Dental Occlusion of the Partially Edentulous Dentition

Abstract

Partially edentulous dentition presents a challenging problem for the surgical planning of digital dental occlusion in the field of craniomaxillofacial surgery because of the incorrect maxillomandibular distance caused by missing teeth. We propose an innovative approach called Dental Reconstruction with Symmetrical Teeth (DRST) to achieve accurate dental occlusion for the partially edentulous cases. In this DRST approach, the rigid transformation between two symmetrical teeth existing on the left and right dental model is estimated through probabilistic point registration by matching the two shapes. With the estimated transformation, the partially edentulous space can be virtually filled with the teeth in its symmetrical position. Dental alignment is performed by digital dental occlusion reestablishment algorithm with the reconstructed complete dental model. Satisfactory reconstruction and occlusion results are demonstrated with the synthetic and real partially edentulous models.

Fig. 1

Overview of the procedure for the reconstruction-based digital dental occlusion of the partially edentulous dentition.

Fig. 2

Digital dental model. (a) Full mandibular model scanned by the 3D laser surface scanner, whose right lateral incisor was missed synthetically. (b) Interested part of the full model, which is employed in the proposed approach. (c) Triangulated mesh surface around the missing tooth. (d) Point cloud on the model surface, which is formed by the vertices of the triangulated mesh.

Fig. 3

Dental segmentation. (a) Range image of the digital dental model in Fig. 2(b). (b) Sequence of raw spokes (red). Some of the spokes are located in the partially edentulous position by mistake; the others indicate each tooth correctly. The black curve is the dental arch curve. (c) The two articulated spokes (yellow) indicate the partially edentulous position. (d) Sequence of the polished spokes (both red and yellow), which correctly segment each tooth and the partially edentulous position.

Fig. 4

Estimate the transformation with a pair of teeth. Consider the partially edentulous dental model in Fig. 2(b), where the right lateral incisor was missed. (a) The right first premolar and the left first premolar were selected as the source tooth (red) and the symmetrical tooth (pink) for estimation. The two teeth are symmetrical with each other and existed on both sides. (b) The symmetrical tooth (pink) was flipped to the other side as the mirrored tooth (blue) by a mirror transformation about the y-O-z plane. (c) The mirrored tooth (blue) was transformed to match the source tooth (red). The parameters that define the transformation were estimated in this way. The concerned areas are highlighted with stripes.

Fig. 5

Fill the partially edentulous space with its symmetrical tooth. Consider the partially edentulous dental model in Fig. 2(b), where the right lateral incisor was missed. (a) The left lateral incisor was selected as the symmetrical tooth (pink) of the partially edentulous position (yellow), where is the related tissue of the missing tooth. (b) The symmetrical tooth (pink) was flipped to the other side as the mirrored tooth (blue) by a mirror transformation about the y-O-z plane. (c) The mirrored tooth (blue) was virtually implanted to the partially edentulous position with the transformation estimated in Fig. 4. The related tissue of the missing tooth was deleted.

Fig. 6

Reconstruction of three synthetic partially edentulous examples. The first row gives three dental models with 1, 2, and 3 teeth extracted. They are produced from the same dental model, which is with full dentition. Specifically, in (a), the right lateral incisor is virtually extracted; in (b), the right first premolar and the right second premolar are virtually extracted; in (c), the right canine, the right first premolar, and the right second premolar are virtually extracted. The partially edentulous space is marked by ellipse. Their corresponding reconstructed dental models are shown in the second (top view) and third rows (front view). The reconstructed entity is pointed out by arrow. The corresponding continuous dental models are in the fourth row.

Fig. 7

Reconstruction of four real partially edentulous models. The first column shows the original partially edentulous models. The partially edentulous space is marked by ellipse. Their corresponding reconstructed dental models are shown in the second column. The reconstructed part is pointed out by arrow. The corresponding continuous models are in the third column. The four real dental models are from three patients. The first patient lost the molars in her left mandibula (the first row). No teeth is missing in her maxilla. The second patient has a seriously deformed second premolar in his left mandibula (the second row). No teeth is missing in his maxilla. The third patient lost the canine in his right maxilla (the third row) and the second molar in his right mandibula (the fourth row).