Human Jaw Motion Simulator MIMU702 Technical Design Report Human Jaw Motion Simulator Project #05 Final Report Design Advisor: Prof. Muftu Design Team Bryan Galer, Nathaniel Hockenberry, James Maloof, Mia Monte-Lowrey, Katelyn O’Donnell April 17, 2007 Department of Mechanical, Industrial and Manufacturing Engineering College of Engineering, Northeastern University Boston, MA 02115 HUMAN JAW MOTION SIMULATOR Design Team Bryan Galer, Nathaniel Hockenberry, James Maloof, Mia Monte-Lowrey, Katelyn O’Donnell Design Advisor / Sponsor Professor Sinan Muftu Abstract The following report describes the anatomy and biomechanics of the human jaw along with design ideas for the development of a realistic jaw simulator. Creating a physical simulation gives hope that controls can be applied to study the jaw’s mechanical properties, dynamic loadings, joint thresholds, and joint degeneration. This knowledge could lead to the ability to test and improve current jaw prosthetics or even to the eventual understanding and treatment of the temporomandibular joint (TMJ) disease. The problems that exist in creating a realistic simulator are the unknown order, direction, and magnitude of muscle forces, the functions of the various ligaments, and the complex TMJ. The project has been broken down into four stages, with the goal of this first stage being simulation of jaw closing. In order to accomplish this goal, three muscles were used: the temporal, the masseter, and the lateral pterygoid muscles. This will be accomplished using servo motors to act as the muscles. The system control is position-based rather than force-based, a decision that was made because the force equations were statically indeterminate. A LabVIEW interface was created to control the position of the jaw and monitor the lengths of each muscle group. The virtual and physical model indicated unrealistic results. Based on our assumptions of perpendicularity, the mandible fell away from the jaw while simulating the closing motion. More analysis needs to be done on jaw movement to continue on with the project in the future. 1 TABLE OF CONTENTS TABLE OF CONTENTS ..............................................................................................................................................2 LIST OF TABLES.........................................................................................................................................................5 Copyright.......................................................................................................................................................................6 1 CHAPTER 1 BACKGROUND INFORMATION .....................................................................................................7 1.1 Introduction .............................................................................................................................................................7 1.1.1 Problem Statement............................................................................................................................................7 1.1.2 Motivation ........................................................................................................................................................7 1.1.3 Problem/ Design Concerns ...............................................................................................................................7 1.2 Temporomandibular Complex (TMC).....................................................................................................................7 1.2.1 Teeth.................................................................................................................................................................7 1.2.2 Bones ................................................................................................................................................................7 1.2.3 Blood vessels and nerves..................................................................................................................................8 1.2.4 Ligaments .........................................................................................................................................................8 1.2.4.1 Collateral Ligament ...................................................................................................................................8 1.2.4.2 Capsular Ligament.....................................................................................................................................9 1.2.4.3 Temporomandibular Ligament ..................................................................................................................9 1.2.4.4 Sphenomandibular Ligament.....................................................................................................................9 1.2.4.5 Stylomandibular Ligament ........................................................................................................................9 1.2.5 Temporomandibular Joint...............................................................................................................................10 1.2.5.1 Components and Functions......................................................................................................................10 1.2.5.2 Finite Element Analysis and Models .......................................................................................................11 1.2.5.3 TMJ Failures and Disorders.....................................................................................................................13 1.2.6 Muscles...........................................................................................................................................................14 1.2.6.1 Skeletal Muscle Introduction...................................................................................................................14 1.2.6.2 Skeletal Muscle Motion...........................................................................................................................15 1.2.6.3 Skeletal Muscle in the Jaw.......................................................................................................................17 1.3 Mechanical Simulations of the TMC.....................................................................................................................23 1.3.1 Muscles...........................................................................................................................................................23 1.3.1.1 Requirements ...........................................................................................................................................23 1.3.1.2 Hydraulic and Pneumatic Rams...............................................................................................................23 1.3.1.3 Servo Drives ............................................................................................................................................24 1.3.1.4 Air Muscles..............................................................................................................................................24 1.3.1.5 Electroactive Polymers ............................................................................................................................25 1.3.1.6 Muscle Wire ............................................................................................................................................26 1.3.2 Ligaments .......................................................................................................................................................27 1.3.3 Articulating Disc.............................................................................................................................................27 1.4 Products and Patents..............................................................................................................................................27 1.4.1 Implant............................................................................................................................................................28 1.4.2 Manual Applications.......................................................................................................................................28 1.4.3 Virtual Applications........................................................................................................................................28 2 CHAPTER 2 – STAGE I: JAW CLOSING .............................................................................................................32 2.1 Introduction ...........................................................................................................................................................32 2.1.1 Problem Statement..........................................................................................................................................32 2.2 Muscle and Ligament Use Decisions.....................................................................................................................32 2.3 Skull Research.......................................................................................................................................................33 2.4 TMJ Simulation .....................................................................................................................................................34 2.4.1 TMJ Friction