dental palatal superimposition of pre- and post-treatment digital models in cloudcompare

Evaluatie van maxillaire posterieure tandbeweging met behulp van digitale superpositie

In 1999, digitally fabricated removable orthodontic appliances were made commercially available by Align (Align Technology Inc., Tempe, AZ). Originally, this system was designed to solve non-growing cases with mild to moderate crowding or close small spaces as an aesthetic alternative to traditional fixed edgewise appliances. With decades of improvements in computer-aided design and manufacturing (CAD/CAM), dental materials, and treatment planning, clear aligner therapy (CAT) has since been used to treat over 10 million patients with various malocclusions worldwide1. A recent retrospective study suggested that CAT is as effective as fixed appliance therapy for the teenage population with mild malocclusions, with significantly improved results in tooth alignment, occlusal relations, and overjet2. The number of appointments, emergency visits, and overall treatment time also had better outcomes for clear aligner therapy patients. Although CAT can be used to treat non-extraction, mild-to-moderate malocclusions in non-growing patients3,4, and shorten treatment duration and chair time5, it remains unclear whether the treatment is as effective as the gold standard of conventional labial braces4,6,7,8,9, especially for anteroposterior and vertical correction10.
ClinCheck is a software platform developed by Align to provide clinicians with virtual three-dimensional (3D) simulations of prospective tooth movements. Primarily concerned with the patient&#39;s initial status and the clinician&#39;s prescribed treatment plan, it can also be a visual communication tool for the patient. Any mismatch between the predicted and achieved results may require a mid-course correction, refinement, or conversion to fixed appliance therapy. Consequently, the reliability of software predictions has drawn increasing attention from investigators. Since Lagravere and Flores-Mir&#39;s systematic review published in 200511, investigations into the concordance between predicted models and post-treatment models have been measured in different ways, measurement methods including arch-length, inter-canine distance, overbite, overjet, midline deviation12, the American Board of Orthodontics objective grading system (ABO-OGS) reduction score13, upper and lower interdental width14, and measures derived from cone-beam computed tomography15.
Comparisons have also been made by superimposing 3D models16,17,18,19,20,21. For example, many current software platforms, such as ToothMeasure (internal software developed by Align Technology), can reproducibly superimpose two digital models using user-selected reference points on untreated teeth, palatal rugae, or dental implants. Since the predicted and achieved models usually do not include the palatal surfaces, many previous studies15,16,17,18 have used the untreated posterior teeth as references for superimposition, including the possibility of adding errors due to the relative movements of these teeth. These studies have been confined to anterior regions of the arch in relatively simple cases with spacing or mild to moderate crowding.
Gr&#252;nheid et al. used mathematical superimposition to quantify the discrepancies between virtual treatment plans and actual treatment outcomes to evaluate the accuracy of full-dentition CAT without stable anatomic structures in digital models20. Haouili et al. used the same method in a best-fit algorithm within the Compare software to conduct a prospective follow-up study on the efficacy of tooth movement with CAT21. The aim was to provide an update on the accuracy associated with emerging technology, i.e., SmartForce, SmartTrack aligner materials, and digital scans. Their findings of an improved overall accuracy from 41%17 to 50%21&#160;were encouraging but do not negate the possibility that some tooth movements are still not satisfactorily achievable with the clear aligner system.
When predicted and achieved, digital models include a common 3D reference independent of the dentition, such as palatal rugae, dental implants, or tori; they can be co-registered within the coordinate system of many suitable software platforms. If a tooth of interest is then segmented from one and transformed mathematically to match its displaced version in the other, the transformation matrix contains the complete information needed to describe the entire 3D transposition. Its content can be expressed as three translations and three rotations described by a formal convention. An example is found on the Invisalign ClinCheck Pro 3D control software, where the numerical parameters indicating the 3D tooth movements needed to move teeth to their predicted positions are shown in a tooth movement table.
While the initial and final (predicted) models from the planning software share a common coordinate system provided by the same software platform, their absence of palates restricts the possibility of co-registering with any other digital dentition model unless they possess identical dentition. In this context, it was hypothesized that the superimposition of software-predicted and post-treatment (achieved) models would be feasible. This feasibility arises from the availability of two pairs: initial and final (automatically superimposed during export from planning software) and another pair of pre-treatment and achieved models (superimposed using palatal rugae). These pairs could be registered using the pre-treatment dentition as a reference to align them with the Invisalign-initial model. Subsequently, the segmentation of individual teeth could be performed to assess differences in their positions and orientations. This assessment involves transposing teeth between the models, and the transformation matrices would enable a numerical quantification of the translations and re-orientations.
In this protocol, an approach to evaluate the effectiveness of CAT in addressing mild to moderate malocclusions in both adolescents and adults was introduced, specifically focusing on the maxillary posterior teeth. The null hypothesis was that there was no difference between the achieved and the planning software-predicted tooth position in the maxillary posterior teeth after the first series of clear aligners.

Auteur in de schijnwerpers: 3D-bewegingsbeoordeling van maxillaire posterieure tanden bij behandeling met clear aligner

Maxillaire posterieure tandbeweging meten: een modelbeoordeling met behulp van palatinale en tandheelkundige superpositie

Dental movement assessment is important when evaluating orthodontic treatment outcomes. We are going to be demonstrating a method to evaluate three-dimensional movement of maxillary posterior teeth when they have undergone Clear Aligner treatment. This protocol offers a combination of several software tools, as well as palatal rugae and dentition as stable references.This combination allows for the superimposition and segmentation of individual teeth for the purpose of analyzing their movements and orientations. This protocols demonstrate a novel method to analyze the differences between software-predicted models and the actual treatment outcomes. By understanding the efficacy and the accuracy of software-predicted treatment, clinicians will have a better judgment planning the tooth movement.

Tandheelkundige palatinale superpositie van digitale modellen voor en na de behandeling in CloudCompare

Start om te beginnen de CloudCompare-software op een computer. Selecteer het digitale maxillaire model na de behandeling en klik op het pictogram roteren vertalen. Sleep het model zodat ze naast elkaar staan en klik op het groene vinkje.Kies het digitale model voor de voorbehandeling en klik op het segmentpictogram. Kies vier punten op de palatinale rugae en klik met de rechtermuisknop om de selectie ongedaan te maken. Klik vervolgens op segmenteren in en druk op het groene vinkje.Verberg de resterende modellen van het model na de retraite en de modellen voor de voorbehandeling, model en selecteer vervolgens het modeldeel na de behandeling en de modellen van het voorbehandelde modeldeel. Druk op het pictogram voor ruwe registratie-uitlijning en plaats ten minste drie oriëntatiepunten aan elke kant van de middellijn voor beide gehemelte. Klik op uitlijnen en vervolgens op het groene vinkje om de plaatsing van het oriëntatiepunt te bevestigen.Maak vervolgens de mazen voor beide modellen zichtbaar. Kopieer vervolgens het resterende model van het niet-getransformeerde model na de behandeling. Klik op Bewerken gevolgd door Transformatie toepassen en plak de transformatiematrix.Verberg de resterende modellen met stippen en selecteer zowel het modelonderdeel na de behandeling als de modellen voor het voorbehandelen van het modelonderdeel. Druk nu op het pictogram voor fijne uitlijning van de registratie en kies het model voor voorbehandeling van het modelonderdeel als referentie en klik vervolgens op OK. Maak de mazen voor beide modellen zichtbaar en verplaats vervolgens het niet-getransformeerde model na de behandeling van het resterende model zoals eerder is gedaan. Klik op Transformatie bewerken en toepassen en plak de transformatiematrix.

Research

JoVE Journal

Medicine

Dental Palatal Superimposition of Pre- and Post-Treatment Digital Models in CloudCompare

Measuring Maxillary Posterior Tooth Movement: A Model Assessment using Palatal and Dental Superimposition

Since the introduction of Invisalign by Align Technology, Inc. in 1999, questions and debates have persisted regarding the precision of Invisalign (clear ...

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