Artificial intelligence is now involved in many aspects of our everyday life. In digital orthodontic practice in particular, practitioners are constantly and mostly unknowingly confronted with different levels of implementations of artificial intelligence. The present article, the third in a three-part series, will seek to shed light on some of these algorithms using common examples from a standard orthodontic digital workflow. Schlagwörter: aligner orthodontics, artificial intelligence, digital orthodontics, machine learning

Artificial intelligence is now involved in many aspects of our daily life. In digital orthodontic practice in particular, practitioners are constantly and mostly unknowingly confronted with different levels of implementations of artificial intelligence. The present article, the second in a three-part series, will seek to shed light on some of these algorithms using common examples from a standard orthodontic digital workflow. Schlagwörter: aligner orthodontics, artificial intelligence, digital orthodontics, machine learning

Artificial intelligence is now firmly established in society. Whether we are searching on Google (Mountain View, CA, USA), being guided by recommendation algorithms or using facial recognition or smart home software, artificial intelligence is a daily presence in our lives, and in almost all areas: business, science, medicine, and increasingly in orthodontics. What is artificial intelligence, what does it encompass, what can it already do in orthodontics and where is it taking us in the discipline? What opportunities does it offer and what negative effects does it have? In this article, the first in a three-part series, we will discuss these questions and strive to answer them. Schlagwörter: aligner orthodontics, artificial intelligence, convolutional neural networks, deep learning, machine learning, neural networks

Early interception of anterior crossbite has functional, structural and aesthetic benefits that have been widely enumerated in the literature. The goal of early interception usually involves proclination of the maxillary incisors, thus eliminating mandibular anterior shift; maxillary disjunction and protraction to correct transverse and sagittal deficiencies, respectively; and maintenance or improvement of mandibular compensation, thus creating as much horizontal overlap as possible. The present study illustrates a case treated for 24 months with a modified Catalan appliance incorporated into in-office aligners. The treatment results highlighted the efficacy of hybrid mechanics for mandibular compensation and protraction of the maxillary dentition. The 5-year follow-up demonstrated relative stability of the final outcome. Schlagwörter: anterior crossbite, Class III treatment, clear aligners, extraoral traction appliance, growing patient, in-office aligners, interceptive orthodontics, maxillary arch expansion, removable orthodontic appliances

Patients with the characteristics of hyperdivergent facial patterns (dolichocephaly, shallow overbite and anterior open bites) are generally considered to be challenging to treat as many biomechanical approaches have extrusive side-effects that may lead to further bite opening and exasperate the clinical issues. However, with the increasing numbers of patients undergoing clear aligner therapy, there is a general clinical consensus that clear aligners are a good treatment option for this group of patients as vertical facial dimensions are not significantly affected with treatment. In the absence of literature on this topic, clinical cases are presented to demonstrate successful treatment of dolichocephalic patients with the ClearCorrect clear aligner system. These cases support the general notion that patients with increased facial dimensions can be treated with clear aligner therapy without adverse vertical changes. Schlagwörter: aligner, facial dimension, hyperdivergent, open bite, orthodontic, vertical

Kiefermodelle können mit Modellscannern, intraoralen Scannern und mittlerweile auch digitalen Volumentomographie (DVT)-Geräten digitalisiert werden. Das Ziel dieser Studie war es, die Genauigkeit von fünf verschiedenen DVT-Geräten bezüglich der Digitalisierung von Gipsmodellen zu untersuchen. Ein als Patient dienendes Studienmodell wurde mittels Doppelmischtechnik abgeformt und die Abformung mit Gips ausgegossen. Am resultierenden Gipsmodell wurden die Masterwerte für die Zahnbogenlänge, die Intermolarenweite und die Intercaninenweite mit einem Koordinatenmessgerät (Zeiss O-Inspect 422) gemessen. Anschließend wurde das Patientenmodell mit fünf DVT-Geräten bei acht Scan-Modi (CS 9300, CS 9300 Select, CS 8100 3D [Carestream]; Promax 3D MidTM [Planmeca] und Whitefox® [Acteon]) gescannt. Pro DVT-Gerät und Modus wurden 37 Scans angefertigt. Die resultierenden DICOM-Daten wurden als Stereolithografie-Daten exportiert und mit einer speziellen Messsoftware (Convince™ Premium 2012 [3Shape]) linear vermessen. Alle Messungen wurden mit den Masterwerten des Patientenmodells verglichen. Die Genauigkeitsmessungen ergaben signifikante Unterschiede zwischen den DVT-Geräten. Die höchsten Genauigkeiten zeigten das Whitefox® (IMW: MW ± SD: 5,5 ± 5,7 µm) und das CS 9300-Gerät (IMW: MW ± SD: -15 ± 7,4 µm). Vergleichbare Werte konnten auch bei geringerer Genauigkeit mit den CS 8100 3D (IMW: MW ± SD: -81,2 ± 7,4 µm) und CS 9300 Select (IMW: MW ± SD: -82,2 ± 6,6 µm) erzielt werden. Das Promax 3D MidTM-Gerät (IMW: MW ± SD: -126,1 ± 4,8 µm) erreichte die schlechtesten Werte. Einige DVT-Geräte eignen sich zur Digitalisierung von Gipsmodellen und weisen klinisch eine sehr gute Genauigkeit auf, sodass Praxen, die mit DVT-Geräten ausgestattet sind, Gipsmodelle digitalisieren könnten, ohne zusätzliche Geräte zu benötigen. Schlagwörter: DVT-Geräte, indirekte Digitalisierung, Gipsmodell, CAD/CAM, Genauigkeit, Stereolithografie

Ziel dieser Studie war der Vergleich der Genauigkeit von sechs Intraoralscannern hinsichtlich drei klinisch relevanter Strecken. Weiterhin sollte die direkte Digitalisierung mit der indirekten Digitalisierung mittels Modelscannern verglichen werden. Ein dreidimensional gedrucktes Studienmodell wurde mit fünf Bohrungen versehen, deren Anordnung die Definition der Strecken Intermolarenweite (IMW), Intercaninenweite (ICW) und Zahnbogenlänge (AL) erlaubte. Um einen Goldstandard zu bestimmen, wurden die Strecken mit einem Koordinatenmessgerät (Zeiss O-Inspect 422) vermessen. Das Studienmodell wurde jeweils 37-mal mit den Intraoralscannern Apollo DI (Sirona), CS 3500 (Carestream), iTero (Cadent), PlanScan (Planmeca), Trios (3Shape), True Definition (3M Espe) und dem Modellscanner OrthoX Scan (Dentaurum) digitalisiert. Die Ganzkieferscans wurden vermessen und Abweichungen zum Goldstandard errechnet. Zwischen den Geräten zeigten sich signifikante Unterschiede. In der Gruppe der Intraoralscanner wiesen Trios und iTero die genauesten Ergebnisse auf. Auch CS 3500, True Definition und Apollo DI zeigten ähnliche Resultate. PlanScan wies die höchsten Abweichungen vom Goldstandard auf und präsentierte eine hohe Standardabweichung. Die direkte Digitalisierung zeigte eine vergleichbare oder gar höhere Genauigkeit als die indirekte Digitalisierung. Beide Methoden erwiesen sich für den Gebrauch in der kieferorthopädischen Praxis als geeignet. PlanScan konnte jedoch die Genauigkeitsanforderungen einer kieferorthopädischen Behandlung nicht erfüllen. Schlagwörter: Intraoralscanner, indirekte Digitalisierung, Ganzkieferscan, digitale Abformung, CAD/CAM, Genauigkeit

Objective: To determine the optimal method to correct rotations of conical teeth using thermoplastic appliances with and without attachments. Introduction: Despite the increasing popularity of clear aligner therapy, there are still questions as to its effectiveness, efficiency, case selection and limitations. It has been reported that the full prescription for clear aligners is not expressed, and that the mean accuracy of any type of tooth movement using clear aligners is only 41% (Drake, 201213). One of the major limitations of clear aligner therapy is the correction of rotated conical teeth, especially canines and premolars (Kravitz, 200814). According to Simon et al (2014)12, mandibular premolar derotation has the lowest predictability of movement and accuracy with clear aligners. This is due to the fact that conical teeth lack interproximal undercuts, and as a result, the aligner tends to slip as derotation is attempted (Kravitz, 2008; Simon, 2014). To address this limitation, the use of resin bonded attachments, interproximal reduction, overcorrection, auxiliaries, or adjusting aligners with thermopliers has been recommended - however the effectiveness of these methods has not been well established. Materials and methods: The design of this in vitro study was prospective and experimental. A comparative study was performed to examine the effect of attachment location and the number of attachments on rotational control of conical teeth relative to control, which was rotational control with no attachments. Total rotation correction was recorded as an angular measurement after placement of each aligner, as measured on a digital scan (Ortho Insight 3D) using Geomagic Design software. Results: Results of a one-way ANOVA showed that there were no statistically significant differences between the six groups. The group with a rectangular attachment on the buccal surface had the highest overall rotational correction. Conclusion: Attachments appear to mildly improve rotational correction of the mandibular right second premolar. Increasing the number of attachments does not appear to aid rotational control, as the group with a single buccal attachment had the highest overall rotational correction. Multiple attachments, and adding attachments to adjacent teeth, appear to impede rotational correction in this study. Schlagwörter: aligner, attachment, auxiliary, orthodontic, rotation