Smart Brackets for 3D-Force-Moment Measurements in Orthodontic Research and Therapy – Developmental Status and Prospects*

Background and Aim:Quantitative knowledge of the three-dimensional (3D) force-moment systems applied for therapeutic tooth movement is of utmost importance, with regard to the predictability of the course of tooth movement, as well as the reduction of traumatic side effects. The concept of a smart bracket with an integrated sensor system for 3D force and moment measurement has recently been published. The feasibility of this approach has been demonstrated using finite-element (FE) simulations and a 2.5 times enlarged real smart bracket model. The aim of this study was to develop and to mechanically characterize the first wire-mediated, true-scale smart bracket.Materials and Methods:A true-scale smart bracket was built using a stress-sensor chip (having a surface area of 2 × 2.5 mm2) and a conventional bracket slot. This bracket was calibrated on a biomechanical system for 3D application and measurement of forces and moments, then its measurement accuracy was evaluated.Results:With the exception of the bucco-lingually-oriented force component, the embedded sensor system was capable of reconstructing the applied force-moment components with sufficient accuracy. The standard deviations for the differences between applied and inferred values were 0.07 N, 0.07 N and 0.26 N for the components Fx, Fy and Fz, and 0.76 Nmm, 1.09 Nmm and 0.22 Nmm for the components Mx, My and Mz.Conclusions:We were able to construct true-scale, wire-mediated smart brackets. Work on improving the sensor system's buccolingual sensitivity is still in progress. Improved smart brackets with wire-mediated energy transmission could be applied in the near future in orthodontic training as an objective feedback tool, as well as in biomechanical research. Broad clinical application of smart brackets requires integration of telemetric components for data and energy transmission. Such components are now being developed. Future clinical application of smart brackets may contribute in reducing the negative side effects of fixed appliance therapy such as root resorption, while enhancing therapeutic efficiency.ZusammenfassungHintergrund und Ziel:Die quantitative Kenntnis der im Rahmen der therapeutischen Zahnbewegung auf die einzelnen Zähne übertragenen dreidimensionalen (3-D) Kraft-Drehmoment-Systeme ist hinsichtlich der Richtungskontrolle bzw. Vorhersagbarkeit der Zahnbewegung sowie der Reduzierung von traumatischen Begleiterscheinungen von eminenter Bedeutung. Im Rahmen einer früheren Arbeit wurde ein Konzept für intelligente Brackets mit integriertem Sensorsystem für 3-D-Kraft-/Drehmomentmessungen vorgestellt und dessen Realisierbarkeit mittels Finite-Elemente-(FE-)Simulationen sowie anhand eines 2,5fach vergrößerten Smart-Bracket-Modells demonstriert. Ziel der vorliegenden Arbeit war die erstmalige Entwicklung und mechanische Charakterisierung eines (kabelversorgten) Smart Brackets im Maßstab 1:1.Material und Methodik:Aus einem Stress-Sensorchip mit einer Oberfläche von 2 × 2,5 mm2 sowie einem konventionellen Bracketslot wurde ein maßstabsgetreues Smart Bracket aufgebaut. Dieses wurde auf einem biomechanischen Messplatz zur 3-D-Applikation und 3-D-Messung von Kräften und Drehmomenten kalibriert und anschließend hinsichtlich seiner Messgenauigkeit evaluiert.Ergebnisse:Mit Ausnahme der in bukkolingualer Richtung orientierten Kraftkomponente war das im Bracket integrierte Sensorsystem in der Lage, die applizierten Kraft- und Drehmomentkomponenten (aus klinischer Sicht) hinreichend genau zu rekonstruieren. Die entsprechenden Standardabweichungen für die Differenzen zwischen applizierten und (mithilfe der Stress-Sensorsignale) rekonstruierten Werte betrugen 0,07 N, 0,07 N, und 0,26 N für die Komponenten Fx, Fy und Fz bzw. 0,76 Nmm, 1,09 Nmm, und 0,22 Nmm für die Komponenten Mx, My und Mz.Schlussfolgerungen:Die Realisierung von maßstabsgetreuen, kabelversorgten Smart Brackets ist möglich, wobei derzeit noch an einer Optimierung des Sensorsystems hinsichtlich seiner Sensitivität für bukkolinguale Kräfte gearbeitet wird. Optimierte Smart-Bracket-Versionen mit Kabelversorgung können in naher Zukunft als objektives Feedback-Tool in der kieferorthopädischen Aus- und Weiterbildung sowie in der biomechanischen Grundlagenforschung eingesetzt werden. Die breite klinische Anwendung von Smart Brackets erfordert die Integration von telemetrischen Komponenten der Daten- und Energieübertragung, deren Entwicklung momentan vorangetrieben wird. Die zukünftige klinische Anwendung von intelligenter Brackettechnologie in der festsitzenden kieferorthopädischen Therapie könnte dazu beitragen, dass die negativen therapeutischen Begleiterscheinungen (wie z. B. Wurzelresorptionen) reduziert und die therapeutische Effizienz gesteigert wird.

[1]  Mulligan Tf,et al.  Common sense mechanics. , 1980 .

[2]  C Bourauel,et al.  An experimental apparatus for the simulation of three-dimensional movements in orthodontics. , 1992, Journal of biomedical engineering.

[3]  C J Burstone,et al.  Centers of rotation with transverse forces: an experimental study. , 1991, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[4]  G Andreasen,et al.  Experimental findings on tooth movements under two conditions of applied force. , 2009, The Angle orthodontist.

[5]  Hao Yu,et al.  Circuitry for a wireless microsystem for neural recording microprobes , 2001, 2001 Conference Proceedings of the 23rd Annual International Conference of the IEEE Engineering in Medicine and Biology Society.

[6]  R.C. Jaeger,et al.  Silicon piezoresistive stress sensors and their application in electronic packaging , 2001, IEEE Sensors Journal.

[7]  J. N. Sweet,et al.  Short and long loop manufacturing feedback using a multisensor assembly test chip , 1990 .

[8]  R P Kusy,et al.  Friction between different wire-bracket configurations and materials. , 1997, Seminars in orthodontics.

[9]  H Miyairi,et al.  Development of an orthodontic simulator for measurement of orthodontic forces. , 2001, Journal of medical and dental sciences.

[10]  Kaare Reitan,et al.  Effects Of Force Magnitude And Direction Of Tooth Movement On Different Alveolar Bone Types , 2009 .

[11]  B G Lapatki,et al.  Smart Bracket for Multi-dimensional Force and Moment Measurement , 2007, Journal of dental research.

[12]  D. W. Palmer,et al.  Short and long loop manufacturing feedback using multi-sensor assembly test chip , 1990, Ninth IEEE/CHMT International Symposium on Electronic Manufacturing Technology,Competitive Manufacturing for the Next Decade.

[13]  R. Storey,et al.  Force in orthodontics and its relation to tooth movement , 1952 .

[14]  J. Morton,et al.  Human tooth movement in response to continuous stress of low magnitude. , 2000, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[15]  E H Hixon,et al.  On force and tooth movement. , 1970, American journal of orthodontics.

[16]  Stanley Braun,et al.  The Gable bend revisited. , 2002, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[17]  H P Bantleon,et al.  An improved transpalatal bar design. Part I. Comparison of moments and forces delivered by two bar designs for symmetrical molar derotation. , 2009, The Angle orthodontist.

[18]  B Melsen,et al.  3-D experimental identification of force systems from orthodontic loops activated for first order corrections. , 1999, The Angle orthodontist.

[19]  O. Paul,et al.  Smart brush based on a high density CMOS stress sensor array and SU-8 microposts , 2007, 2007 IEEE 20th International Conference on Micro Electro Mechanical Systems (MEMS).

[20]  G Rau,et al.  Measuring system for in vivo recording of force systems in orthodontic treatment-concept and analysis of accuracy. , 1999, Journal of biomechanics.

[21]  D. W. Peterson,et al.  Design and Experimental Evaluation of a 3rd Generation Addressable CMOS Piezoresistive Stress Sensing Test Chip , 1999 .

[22]  K Reitan,et al.  Some factors determining the evaluation of forces in orthodontics , 1957 .

[23]  C. Burstone,et al.  Mechanics of tooth movement. , 1984, American journal of orthodontics.

[24]  C Bourauel,et al.  Determination of the centre of resistance in an upper human canine and idealized tooth model. , 1999, European journal of orthodontics.

[25]  Stavros Kiliaridis,et al.  Experience of pain during an orthodontic procedure. , 2002, European journal of oral sciences.

[26]  C. Burstone,et al.  Creative wire bending--the force system from step and V bends. , 1988, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[27]  Franz Günter Sander,et al.  Development and Biomechanical Investigation of a New Compound Palatal Arch , 2004, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[28]  U Belser,et al.  A Nonlinear Elastic Model of the Periodontal Ligament and its Numerical Calibration for the Study of Tooth Mobility , 2002, Computer methods in biomechanics and biomedical engineering.

[29]  S. A. Gee,et al.  Strain-gauge mapping of die surface stresses , 1989 .

[30]  Dieter Drescher,et al.  Force Systems in the Initial Phase of Orthodontic Treatment—a Comparison of Different Leveling Archwires , 2006, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[31]  Henry Baltes,et al.  Offset reduction in Hall devices by continuous spinning current method , 1998 .

[32]  Christoph Bourauel,et al.  Determination of the Elasticity Parameters of the Human Periodontal Ligament and the Location of the Center of Resistance of Single-rooted Teeth A Study of Autopsy Specimens and Their Conversion into Finite Element Models , 2002, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[33]  Peter Diedrich,et al.  In vitro testing of a measuring system for in vivo recording of orthodontically applied forces and moments in the multiband technique , 2005, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[34]  R. Kusy,et al.  Influence of force systems on archwire-bracket combinations. , 2005, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[35]  L Keilig,et al.  Numerical simulation of the biomechanical behaviour of multi-rooted teeth. , 2005, European journal of orthodontics.

[36]  Christoph Bourauel,et al.  Application of Bone Remodeling Theories in the Simulation of Orthodontic Tooth Movements , 2000, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[37]  Lu-Ping Chao,et al.  Shape optimal design and force sensitivity evaluation of six-axis force sensors , 1997 .

[38]  Charles S. Smith.  Piezoresistance Effect in Germanium and Silicon , 1954 .

[39]  R S Quinn,et al.  A reassessment of force magnitude in orthodontics. , 1985, American journal of orthodontics.

[40]  Martin Geiger,et al.  Numerical experiments on long-time orthodontic tooth movement. , 2002, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[41]  Charles J. Burstone,et al.  A Device for Determining the Mechanical Behavior of Orthodontic Appliances , 1977, IEEE Transactions on Biomedical Engineering.

[42]  Fan-Gang Tseng,et al.  An elastomeric tactile sensor employing dielectric constant variation and applicable to orthodontia , 2004, 17th IEEE International Conference on Micro Electro Mechanical Systems. Maastricht MEMS 2004 Technical Digest.

[43]  O. N. Tufte,et al.  Piezoresistive Properties of Silicon Diffused Layers , 1963 .

[44]  Christina Dorow,et al.  Development of a Model for the Simulation of Orthodontic Load on Lower First Premolars Using the Finite Element Method , 2005, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[45]  B Melsen,et al.  Tissue reaction to orthodontic tooth movement--a new paradigm. , 2001, European journal of orthodontics.

[46]  Franz-Günter Sander,et al.  Root Resorptions in Upper First Premolars after Application of Continuous Torque Moment Intra-Individual Study , 2001, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[47]  D Lundgren,et al.  Effects of a doubled orthodontic force magnitude on tooth movement and root resorptions. An inter-individual study in adolescents. , 1996, European journal of orthodontics.

[48]  O. Paul,et al.  Integrated Six-Degree-Of-Freedom Sensing for Orthodontic Smart Brackets , 2006, 19th IEEE International Conference on Micro Electro Mechanical Systems.

[49]  Guy De Pauw,et al.  The value of the centre of rotation in initial and longitudinal tooth and bone displacement. , 2003, European journal of orthodontics.

[50]  E. Chan,et al.  Physical properties of root cementum: Part 5. Volumetric analysis of root resorption craters after application of light and heavy orthodontic forces. , 2005, American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics.

[51]  D. Zwanziger,et al.  A clinical evaluation of the differential force concept as applied to the edgewise bracket. , 1980, American journal of orthodontics.

[52]  Edgar H. Callaway,et al.  Wireless Sensor Networks: Architectures and Protocols , 2003 .

[53]  Steven J. Lindauer,et al.  The basics of orthodontic mechanics , 2001 .

[54]  L. Johnston,et al.  A clinical investigation of the concepts of differential and optimal force in canine retraction. , 2009, The Angle orthodontist.

[55]  J. Schwizer,et al.  Packaging test chip for flip-chip and wire bonding process characterization , 2003, TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664).

[56]  Thomas F. Mulligan,et al.  Understanding Wire/Bracket Relationships , 2002, Journal of Orofacial Orthopedics / Fortschritte der Kieferorthopädie.

[57]  R. Pryputniewicz,et al.  Holographic determination of centers of rotation produced by orthodontic forces. , 1980, American journal of orthodontics.