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

Objective: The primary objective of this study was to compare the accuracy and time efficiency of an indirect and direct digitalization workflow with that of a three-dimensional (3D) printer in order to identify the most suitable method for orthodontic use. Method and Materials: A master model was measured with a coordinate measuring instrument. The distances measured were the intercanine width, the intermolar width, and the dental arch length. Sixty-four scans were taken with each of the desktop scanners R900 and R700 (3Shape), the intraoral scanner TRIOS Color Pod (3Shape), and the Promax 3D Mid cone beam computed tomography (CBCT) unit (Planmeca). All scans were measured with measuring software. One scan was selected and printed 37 times on the D35 stereolithographic 3D printer (Innovation MediTech). The printed models were measured again using the coordinate measuring instrument. Results: The most accurate results were obtained by the R900. The R700 and the TRIOS intraoral scanner showed comparable results. CBCT-3D-rendering with the Promax 3D Mid CBCT unit revealed significantly higher accuracy with regard to dental casts than dental impressions. 3D printing offered a significantly higher level of deviation than digitalization with desktop scanners or an intraoral scanner. The chairside time required for digital impressions was 27% longer than for conventional impressions. Conclusion: Conventional impressions, model casting, and optional digitization with desktop scanners remains the recommended workflow process. For orthodontic demands, intraoral scanners are a useful alternative for full-arch scans. For prosthodontic use, the scanning scope should be less than one quadrant and three additional teeth. Schlagwörter: 3D printed models, accuracy, CBCT model scan, desktop model scanner, digitalization, full-arch scans, intraoral scanner

Objectives: The aim of this experimental study is to evaluate the accuracy of the MExPERT IPM (implant planning model) and the surgical drill guide fabricated from that model. Material and methods: DICOM data from a CBCT (MESANTIS line I; ISI, Hatfield, USA) and STL data from a plaster model scanned with the model scanner D700 (3Shape, Kopenhagen, Denmark) were matched with each other in a specific implant planning software (MESANTIS 3D Studio). Based on the matched data an implant for tooth 36 was planned with a patented new approach. In the base of the virtual model four precise wholes were placed as reference markers. The distance of the sagittal markers was 30.000 µm and the distance of the transversal markers was 25.000 µm in the virtual model. Subsequently, acrylic models were printed with Scan LED (MOVINGLight®) technology (D35, Prodways, Les Mureaux, France). All printed IPMs were evaluated with the high-end scanning system CONTURA G2 (Carl Zeiss, Oberkochen, Germany). To assess the basic accuracy of the IPM the sagittal and transversal distances of the reference markers were measured. After repeated placing of the Camlog sleeve holder (= IPM marker) in the planned hole of the printed IPM the vertical variation of the IPM marker was measured. In addition, the variation of the IPM marker angulation in the sagittal and transversal plane was evaluated. In the second part of the study the fabricated implant guide was evaluated with the same parameters. Results: The mean deviation of the MExPERT IPM was 101 µm (= 0,33%) in the sagittal and 24 µm (0,4%) in the transversal dimension. Repeated positioning of the IPM-Marker on the MExPERT IPM was associated with a vertical variation of 37µm. The angular deviation of the IPM marker in the sagittal dimension was 0,33° and in the transversal dimension 0,77°. In the fabricated implant guide the vertical position of the Camlog sleeve varied 163 µm. The mean angular deviation of the sleeve in the implant guide was 0,4° in sagittal plane and 1,15° in transversal plane. Conclusion: When compared with other scientific studies the MExPERT IPM Camlog seems to be the most accurate and economical implant guide for safe and fast implant placement. Schlagwörter: computer-aided surgery (CAS), cone-beam imaging (CBCT), dental implantology, surgical templates, drill templates, surgical guides