Software Support for Advanced Cephalometric Analysis in Orthodontics

Software Support for Advanced Cephalometric Analysis in Orthodontics

Demetrios J. Halazonetis (National Kapodistrian University of Athens, Greece)
DOI: 10.4018/978-1-60566-292-3.ch001
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Cephalometric analysis has been a routine diagnostic procedure in Orthodontics for more than 60 years, traditionally employing the measurement of angles and distances on lateral cephalometric radiographs. Recently, advances in geometric morphometric (GM) methods and computed tomography (CT) hardware, together with increased power of personal computers, have created a synergic effect that is revolutionizing the cephalometric field. This chapter starts with a brief introduction of GM methods, including Procrustes superimposition, Principal Component Analysis, and semilandmarks. CT technology is discussed next, with a more detailed explanation of how the CT data are manipulated in order to visualize the patient’s anatomy. Direct and indirect volume rendering methods are explained and their application is shown with clinical cases. Finally, the Viewbox software is described, a tool that enables practical application of sophisticated diagnostic and research methods in Orthodontics.
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Geometric Morphometrics

Geometric morphometrics uses mathematical and statistical tools to quantify and study shape (Bookstein, 1991; Dryden & Mardia, 1998; Slice, 2005). In the domain of GM, shape is defined as the geometric properties of an object that are invariant to location, orientation and scale (Dryden & Mardia, 1998). Thus, the concept of shape is restricted to the geometric properties of an object, without regard to other characteristics such as, for example, material or colour. Relating this definition to cephalometrics, one could consider the conventional cephalometric measurements of angles, distances and ratios as shape variables. Angles and ratios have the advantage that they are location- and scale-invariant, whereas distances, although not scale-invariant, can be adjusted to a common size. Unfortunately, such variables pose significant limitations, a major one being that they need to be of sufficient number and carefully chosen in order to describe the shape of the object in a comprehensive, unambiguous manner. Consider, for example, a typical cephalometric analysis, which may consist of 15 angles, defined between some 20 landmarks. It is obvious that the position of the landmarks cannot be recreated from the 15 measurements, even if these have been carefully selected. The information inherent in these shape variables is limited and biased; multiple landmark configurations exist that give the same set of measurements. A solution to this problem (not without its own difficulties) is to use the Cartesian (x, y) coordinates of the landmarks as the shape variables. Notice that these coordinates are also distance data (the distance of each landmark to a set of reference axes), so they include location and orientation information, in addition to shape. However, the removal of this ‘nuisance’ information is now more easily accomplished, using what is known as Procrustes superimposition.

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Table of Contents
Petros Koidis
Andriani Daskalaki
Andriani Daskalaki
Chapter 1
Demetrios J. Halazonetis
Cephalometric analysis has been a routine diagnostic procedure in Orthodontics for more than 60 years, traditionally employing the measurement of... Sample PDF
Software Support for Advanced Cephalometric Analysis in Orthodontics
Chapter 2
Jorg Hendricks, Gert Wollny, Alexander Hemprich, Thomas Hierl
This chapter presents a toolchain including image segmentation, rigid registration and a voxel based non-rigid registration as well as 3D... Sample PDF
A New Software Environment for 3D-Time Series Analysis
Chapter 3
Antheunis Versluis, Daranee Tantbirojn
Residual stress due to polymerization shrinkage of restorative dental materials has been associated with a number of clinical symptoms, ranging from... Sample PDF
Relationship Between Shrinkage and Stress
Chapter 4
Andreas Vogel
This chapter introduces a computer-controlled method for mandible alignment. The exact positioning of the mandible in relation to the maxilla is... Sample PDF
An Objective Registration Method for Mandible Alignment
Chapter 5
Thomas Hierl, Heike Huempfner-Hierl, Daniel Kruber, Thomas Gaebler, Alexander Hemprich, Gert Wollny
This chapter discusses the requirements of an image analysis tool designed for dentistry and oral and maxillofacial surgery focussing on 3D-image... Sample PDF
Requirements for a Universal Image Analysis Tool in Dentistry and Oral and Maxillofacial Surgery
Chapter 6
N.A. Borghese, I. Frosio
This chapter shows how large improvement in image quality can be obtained when radiographs are filtered using adequate statistical models. In... Sample PDF
Denoising and Contrast Enhancement in Dental Radiography
Chapter 7
Ralf K.W. Schulze
Established techniques for three-dimensional radiographic reconstruction such as computed tomography (CT) or, more recently cone beam computed... Sample PDF
3D Reconstructions from Few Projections in Oral Radiology
Chapter 8
Shital Patel, Yos Morsi
Tooth loss due to several reasons affects most people adversely at some time in their lives. A biological tooth substitute, which could not only... Sample PDF
Advances and Trends in Tissue Engineering of Teeth
Chapter 9
Wei-Bang Chen, Chengcui Zhang
Bacterial colony enumeration is an essential tool for many widely used biomedical assays. This chapter introduces a cost-effective and fully... Sample PDF
Automated Bacterial Colony Counting for Clonogenic Assay
Chapter 10
Michele Jacotti, Domenico Ciambrone
In this chapter the authors describe a new system for guided surgery in implantology. The aim of this system is to have a “user friendly”... Sample PDF
A New System in Guided Surgery: The Flatguide(TM) System
Chapter 11
Ferenc Pongracz
Intraoperative transfer of the implant and prosthesis planning in dentistry is facilitated by drilling templates or active, image-guided navigation.... Sample PDF
Visualization and Modelling in Dental Implantology
Chapter 12
Antonios Zampelis, George Tsamasphyros
Biomechanical research has gained recognition in medical sciences. Osseointegrated dental implants, being medical devices functioning under constant... Sample PDF
Finite Element Analysis and its Application in Dental Implant Research
Chapter 13
Amit Chattopadhyay, Tiago Coelho de Souza, Oscar Arevalo
Electronic Oral Health Records (EOHRs) contains all personal health information belonging to an individual and is entered and accessed... Sample PDF
Electronic Oral Health Records in Practice and Research
Chapter 14
Maxim Kolesnikov, Arnold D. Steinberg, Milos Zefran
This chapter describes the haptic dental simulator developed at the University of Illinois at Chicago. It explores its use and advantages as an... Sample PDF
Haptic-Based Virtual Reality Dental Simulator as an Educational Tool
Chapter 15
Anka Letic-Gavrilovic
In this chapter, the author will demonstrate and describe a project to develop a unique database with multilingual information and knowledge... Sample PDF
Digital Library for Dental Biomaterials
Chapter 16
Petros Koidis, Marianthi Manda
The present chapter deals with the introduction and implementation of rapid prototyping technologies in medical and dental field. Its purpose is to... Sample PDF
Rapid Prototyping and Dental Applications
Chapter 17
Hiroo Tamagawa, Hideaki Amano, Naoji Hayashi, Yasuyuki Hirose
In this chapter, the authors report the minimal set of characters from the Unicode Standard that is sufficient for the notation of human dentition... Sample PDF
Unicode Characters for Human Dentition: New Foundation for Standardized Data Exchange and Notation in Countries Employing Double-Byte Character Sets
Chapter 18
Nikos Nikolaidis, Ioannis Marras, Georgios Mikrogeorgis, Kleoniki Lyroudia, Ioannis Pitas
The availability of datasets comprising of digitized images of human body cross sections (as well as images acquired with other modalities such as... Sample PDF
Virtual Dental Patient: A 3D Oral Cavity Model and its Use in Haptics-Based Virtual Reality Cavity Preparation in Endodontics
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