3D superimposition of dental casts based on coloured landmark detection using combined computer vision and 3D computer graphics techniques

ABSTRACT

The aim of this study was to evaluate the validity and reliability of three-dimensional (3D) landmark-based palatal superimposition of digital dental models using the customized software Ortho Mechanics Sequential Analyzer (OMSA) revised by the addition of a computer vision algorithm. The sample consisted of pre- and post-treatment digital maxillary dental models of 20 orthodontic cases. For each case, the pre- and post-treatment digital models were superimposed using colour detection capabilities of a computer vision algorithm added to OMSA. The same set of parameters was measured on the superimposed 3D data by the two software versions for comparison. Agreement in the superimposition outcomes among the two superimposition methods was evaluated with Dahlberg error (DE), intraclass correlation coefficients (ICCs) using two-way ANOVA mixed model for absolute agreement and Bland–Altman agreement limits (LOA). Repeatability was excellent for all variables (all ICCs over 0.99 with the lower 95% confidence limit ≥0.95). The Dahlberg error (DE) ranged from 0.14 mm to 0.36 mm. The absolute error did not exceed 0.5 mm for any variable. The results indicate that OMSA with computer vision algorithms offers a valid and reliable tool for 3D landmark-based digital dental model superimposition using colour detection of three reference points marked along the mid-palatal raphe.

KEYWORDS:

• Orthodontics
• dental cast
• superimposition
• computer vision

Disclosure statement

No potential conflict of interest was reported by the authors.

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Additional information

Notes on contributors

Sameh Talaat

Dr. Sameh Talaat obtained his master’s degree in orthodontics in 2012 from University of Cairo in Egypt and he got his fellowship in the Royal College of Surgeons of Edinbugh in Orthodontics in 2017. Dr. Talaat has been involved in the launch of mixed reality digital technology researches in the Department of Oral Technology at University of Bonn in Germany. Dr Talaat is an assistant Lecturer of orthodontics, in the Department of Orthodontics, Future University in Egypt. He is actively involved in research and teaching on the subject of diagnosis and treatment planning particularly in using recent algorithms for handling digital dental models.

Ahmed Kaboudan

Dr. Ahmed Kaboudan obtained his master degree in Orthodontics in 1985 from the university of “Pierre et Marie Curie”, Paris, France, Followed by a PhD in Artificial Intelligence (computer science) from WIU, Washington, USA. He has a long career in teaching, research and development, and a continuous flow of publications in Orthodontics and Computer Science in high impact journals, backed by USA patents. His research topics span a broad spectrum of highly specialized and interdisciplinary topics, mainly in Dentistry, Orthodontics, Artificial Intelligence, Massively Parallel Computing, Computer Vision and Mixed Reality. Dr. Ahmed Kaboudan has many distinguished positions in teaching and management in both the governmental private sectors, as well as consultancy for major organizations and ministries of health. He was awarded numerous prizes, and elected “man of the year” by Egypt developers. Currently he is a visiting professor of computer science, Elshorouk Academy, Egypt, and the Chief Research Officer at DigiBrain4 Inc., Chicago, USA.

Omar Abdelbary

Dr. Omar Abdelbary obtained his master’s degree in prosthodontics in 2015 from Ain Shams University in Egypt. Dr Omar Abdelbary is an assistant Lecturer of Prosthodontics, in the Department of Prosthodontics, Future University in Egypt. He is actively involved in research and teaching on the subject of fixed prosthodontics particularly in esthetics, color reproduction, and optical properties of different dental materials. His works have been published in refereed journals. Dr. Omar Abdelbary is actively involved in research involving different properties of latest esthetic restorative dental materials. Currently he is a doctoral degree researcher at department of fixed prosthodontics at Ain Shams University, studying new tooth preparation designs using novel esthetic material.

Katherine Kula

Katherine Kula, MS, DMD, MS. Diplomate, American Board of Orthodontics. Professor Emeritus, Department of Orthodontics and Orofacial Genetics, Indiana University School of Dentistry.

Ahmed Ghoneima

Dr. Ahmed Ghoneima is Associate Professor and Chair of Orthodontic Department at Hamdan Bin Mohammed College of Dental Medicine (HBMCDM), Mohammed Bin Rashid University of Medicine and Health Sciences (MBRU), Dubai, UAE. He is a Diplomate of the American Board of Orthodontics and has authored over 50 peer-reviewed publications as well as several book chapters about 3D imaging in orthodontics and cephalometric analysis.

Reinhard Klein

Reinhard Klein studied Mathematics and Physics at the University of Tübingen, Germany, from where he received his diploma in Mathematics and his PhD in Computer Science. In 1999 he became full professor at the University of Darmstadt, Germany, and head of the research group Animation and Image Communication at the Fraunhofer Institute for Computer Graphics. Since 2000 he is professor at the University of Bonn and director of the Institute of Computer Science II. His research interests include Scientific Visualization and Visual Analytics, Geometry Processing, Digital Material Appearance and Rendering as well as Augmented and Virtual Reality.

Christoph Bourauel

Christoph Bourauel is Professor and Head of the Department of Oral Technology at the University of Bonn. He studied Physics at the University of Bonn and received his Diploma in Laser Spectroscopy at the Institute of Applied Physics of the University of Bonn. He earned a Dr.rer.nat. in Physics with an interdisciplinary study on NiTi alloys and has also completed his Habilitation at the Medical Faculty of the University of Bonn. He received his venia legendi in the field of Experimental Dentistry and Biomechanics. His research focuses on Dental Biomechanics and Materials Science. Prof. Bourauel serves as convenor of the Standards Group on Orthodontic Products in the DIN, as convenor of the ISO Standards Group on “Orthodontic anchors” and was president of the German Society of Biomechanics.