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

Abstract

The present study aimed to establish and evaluate a method for recording edentulous jaw relations digitally without occlusal bases, using a handheld scanner and specially designed headgear. The headgear maintained the mandibular position. Ten edentulous patients’ upper (U) and lower edentulous jaw models (L) were prepared and scanned. A handheld scanner was used to capture the labial alveolar ridge mucosa relations in the upper and lower anterior arches directly (Dr). U and L were registered to Dr (test group). Complete dentures of patients in the intercuspal position were used to construct the relationship between U and L (control group). Differences in jaw relations in the test and control groups, in terms of vertical difference, displacement and rotation of the anterior and posterior, and displacement and rotation of the left and right were assessed using the Hotelling’s T2 test. The differences in the mean values and the mean of the absolute values of the jaw relations between groups were not statistically significant (P = 0.331) and significant (P = 0.016), respectively. Our findings show that it is possible to make digital recording of edentulous jaw relations by using a handheld scanner and headgear.

Comparison of the Accuracy of the Image Registration Methods for the impressions of edentulous jaws

“…A prerequisite for a 3D comparative study was the reliable registration method of 3D models (also named alignment, registration, superimposed, or overlapped) [3,4,5,9,10]. Registration is also an indispensable tool for digital clinical dentistry of edentulous jaws [11,12], such as transferring jaw relations in digital complete dentures, aligning jaw relation records with impressions, and aligning radiographic templates with CBCT in preoperative implant design [13,14,15,16]. There are three main recorded model registration methods in the literature: Scanner's own software, such as 3Shape, which performs alignment by manually selecting three points and calculating internally [5]; Reverse engineering software, in which the most widely used registration method is the best t alignment tool [ 2,3,6,7], which is also recommended for model alignment in reverse engineering software for product quality analysis; and When Chen Sihan et al studied the accuracy of intraoral scanning of complete dentition, they used the manual registration command rst and then the global registration command for model alignment in reverse engineering software [8].…”

Quantitative evaluation of edentulous maxillomandibular relationship record using diagnostic complete dentures fabricated by CAD and 3D printing

“…Li et al [19] proposed a method for quantitative evaluation of 3D jaw casts in terms of the maxillomandibular relationship by using positioning cylinders adherent to gypsum casts, although the procedures for adhesion and contact measurement using the cylinders were complex and time-consuming. Later, [20] they developed a new method for evaluating displacements of the maxillomandibular relationship by referring to the complete denture with artificial teeth in the intercuspal position, but without consideration of the centric relationship position. In terms of the latter, which is the clinically repeatable reference position [21], it is convenient to assess and analyze the accuracy of maxillomandibular relationship records in a clinic by using a gothic arch tracer, which yields a visual display of displacements in the maxillomandibular relationship.…”

Restorative Space Analysis by Jaw Motion Tracking Using a Template in Completely Edentulous Patients

“…The dental technique described herein uses a digital approach to analyze the restorative space and establish a new vertical dimension using the old denture as a target-tracking template for patients whose old dentures have worn out and have a reduced vertical dimension. A previous study proposed a target-tracking method to determine maxillomandibular relationships in completely edentulous patients, but that method required the patient to wear headgear for recording the jaw relationships, and only static relationships were determined [17]. In contrast, our technique uses a target-tracking method to record the dynamic movements of the jaws and analyze the restorative space after determining the maxillomandibular relationship.…”