Accuracy evaluation of a new three-dimensional reproduction method of edentulous dental casts, and wax occlusion rims with jaw relation

Abstract

The article introduces a new method for three-dimensional reproduction of edentulous dental casts, and wax occlusion rims with jaw relation by using a commercial high-speed line laser scanner and reverse engineering software and evaluates the method's accuracy in vitro. The method comprises three main steps: (i) acquisition of the three-dimensional stereolithography data of maxillary and mandibular edentulous dental casts and wax occlusion rims; (ii) acquisition of the three-dimensional stereolithography data of jaw relations; and (iii) registration of these data with the reverse engineering software and completing reconstruction. To evaluate the accuracy of this method, dental casts and wax occlusion rims of 10 edentulous patients were used. The lengths of eight lines between common anatomic landmarks were measured directly on the casts and occlusion rims by using a vernier caliper and on the three-dimensional computerized images by using the software measurement tool. The direct data were considered as the true values. The paired-samples t-test was used for statistical analysis. The mean differences between the direct and the computerized measurements were mostly less than 0.04 mm and were not significant (P>0.05). Statistical significance among 10 patients was assessed using one-way analysis of variance (P<0.05). The result showed that the 10 patients were considered statistically no significant. Therefore, accurate three-dimensional reproduction of the edentulous dental casts, wax occlusion rims, and jaw relations was achieved. The proposed method enables the visualization of occlusion from different views and would help to meet the demand for the computer-aided design of removable complete dentures.

A pilot study of digital recording of edentulous jaw relations using a handheld scanner and specially designed headgear

“…Traditionally, the jaw relations in edentulous individuals are recorded in the clinic using occlusal bases, and an upper model, upper occlusal base, lower model, lower occlusal base, and the labial/buccal surface of the models fixed by occlusal bases must be scanned individually. Thereafter, the ICP algorithm of the common labial/buccal surface that is used for 3D construction of the edentulous jaw model with the jaw relations is implemented 31 . 3D construction of edentulous jaw relations by means of commercial complete denture systems, such as Avadent, Dentaca, and 3Shape, also use occlusal bases that are scanned extraorally 27 – 29 .…”

Fabricating Complete Dentures with CAD/CAM and RP Technologies

“…Several studies have been conducted to measure the accuracy of these devices, and the measurement of working models with calipers is assumed to be the standard. These measurements have been compared with digital measurements …”

“…Previous studies have shown how accurate results can be obtained through digital impression techniques . According to the findings of more recent studies, mistakes that previously occurred during the clinical and laboratory phases can now be prevented, owing to the extreme accuracy afforded by digital impression devices, and the repetitions required for conventional impression techniques can now be avoided. Furthermore, obtaining direct digital impressions from edentulous patients is a topic of much discussion because of the displaceability of soft tissues .…”

Evaluation of the Quantitative Accuracy of 3D Reconstruction of Edentulous Jaw Models with Jaw Relation Based on Reference Point System Alignment

“…The reconstruction error directly determines CAD accuracy for complete denture. Previous studies have indicated that the use of a model spatial relation positioning device supported by a dental model 3D scanner (dental articular positioning) and the common regional registration method can control the reconstruction error of jaw relation within one hundred microns [ 1 , 2 ]. However, this method requires respective completion of five scanning operations on the upper jaw model, upper jaw dentures, lower jaw model, lower jaw dentures, and double jaw model/dentures of the complete labial and buccal surface.…”