Utilizing three-dimensional data in orthodontic practice and research

Validation of automated registration of intraoral scan onto Cone Beam Computed Tomography for an efficient digital dental workflow

OBJECTIVE

This study aimed to validate a newly developed automated method (Virtual Patient Creator, Relu, Leuven, Belgium) for multimodal registration of intraoral scan (IOS) and Cone Beam Computed Tomography (CBCT).

METHODS

Time point-matched IOS and CBCT scans of forty patients with variable dental statuses (natural dentition, partial edentulism, presence of orthodontic brackets) were selected. Three operators registered IOS and CBCT scans using three state-of-the-art softwares for orthodontics and orthognathic surgery (IPS Case Designer, Proplan CMF and Dolphin Imaging). Automated registration was compared to expert-performed semi-automated registration. Time consumption, accuracy, and consistency of the proposed method were benchmarked to semi-automated registration using root mean squared error calculations. The robustness of the automated registration was evaluated in relationship to the dental status of the patients in the dataset.

RESULTS

On average, automatic registration was 7.3 times faster than semi-automatic registration performed by an expert operator. Automatic registration yielded reliable results with low deviation errors compared to the differently skilled operators and semi-automated software. Automated registration surpassed human variability as expressed in intra- and inter-operator inconsistencies. Neither orthodontic brackets nor edentulism impacted registration accuracy.

CONCLUSIONS

The presented automated method for IOS and CBCT registration is faster, equally accurate, and more consistent than semi-automatic registration performed by an expert or an occasional operator. With similar results among cases with different dental statuses, the clinical feasibility of the method is ensured.

CLINICAL SIGNIFICANCE

A validated automated registration method provides accurate and fast multimodal image integration without incorporating operator bias at the very start of the digital workflows for dentistry, periodontics, orthodontics and orthognathic surgery.

3D Technology Used for Precision in Orthodontics

One of the most crucial technologies used by orthodontists to assess and document the dimensions of craniofacial features is imaging. Orthodontists frequently employ two-dimensional (2D) imaging methods, although 2D imaging cannot localize or determine the depth of structures. Early in the 1990s, three-dimensional (3D) imaging was invented, and it has since become a crucial part of dentistry, especially in orthodontics. One of the newest and most important breakthroughs in dentistry is 3D technology. Clinicians have been able to significantly improve patient care while also shortening the time spent on treatment planning due to these technologies, which include intra-oral scanning, 3D imaging, computed-axial tomography (CAT) scan, cone-beam computed tomography (CBCT), computer-aided design/computer-aided manufacturing (CAD/CAM), and 3D software. 3D models of maxillary and mandibular arches can take the place of conventional plaster casts and their limits for planning treatments, appliance production, and estimated treatment results as part of this continuous progress. Digital orthodontics procedures have become more popular in the recent past. The development of "personalized" orthodontic appliances makes use of technology. These technologies' overall improvement can increase clinicians' productivity and efficiency by simplifying traditional methods that are seen to be particularly laborious. The objectives of this review are to provide an overall description of the 3D technology nowadays and to assess its orthodontic applications.

Application of Three-Dimensional Digital Technology in Orthodontics: The State of the Art

Three-dimensional technologies are one of the most recent and relevant advancements in the field of Dentistry. These systems, including intraoral scans, 3D imaging exams (CAT scan, CBCT and MRI), CAD/CAM 3D printing devices and 3D computer software, have enabled clinicians to greatly improve patient care along with reducing treatment planning time. The present descriptive study aims to explore possible applications of 3D technologies during the diagnosis, treatment plan, case monitoring and result assessment in orthodontics. The overall upgrade provided by these technologies can improve the clinicians’ workflow and effectiveness by simplifying conventional techniques considered to be especially arduous.

Two-dimensional versus three-dimensional Frӓnkel Manoeuvre: a reproducibility study

Background/Objectives

To assess intra- and inter-observer reproducibility of the evaluation of the Frӓnkel Manoeuvre (FM) on three-dimensional (3D) scans and to compare it to the assessment on two-dimensional (2D) pictures.

Materials/Methods

This study included 44 individuals with a skeletal Class II malocclusion [9–16-years old mean age ± standard deviation: 13.5 ± 2.01 years]. All patients had a full Class II molar relationship, overjet ≥6 mm and point A, Nasion, point B angle (ANB) ≥5 degrees. During the FM, each patient was invited to bite in centric occlusion and then to posture the mandible forward to reach a Class I molar relationship. The FM was recorded both by a normal camera and a 3D scanner (3dMD system). Six examiners divided into two groups according to their orthodontic clinical experience (<5 and >10 years), and one gold standard in the evaluation of FM, commented twice (every 15 days) on both 2D photographs (T0 and T2) and 3D scans (T1 and T3). The intra-observer agreement and the inter-observer agreement compared to the gold standard were evaluated by computing the Cohen’s K.

Results

The agreement between observations for each examiner ranged from 0.36 to 1 on 2D pictures (T0 versus T2), and from 0.22 to 0.69 on 3D scans (T1 versus T3). The overall agreement was 0.63 (95 per cent CI = 0.35–0.91) in 2D analysis and 0.5 (95 per cent CI = 0.35–0.64) in 3D analysis.

Conclusions/Implications

The FM was less reproducible when performed on 3D records than on 2D pictures.