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Myths of orthodontic gnathology

2009; Elsevier BV; Volume: 136; Issue: 3 Linguagem: Inglês

10.1016/j.ajodo.2008.04.021

1097-6752

Donald J. Rinchuse, Sanjivan Kandasamy,

Oropharyngeal Anatomy and Pathologies

Dr Beverly McCollum established the Gnathologic Society in 1926. Gnathology is defined as "the science that treats the biology of the masticatory mechanism as a whole: that is, the morphology, anatomy, histology, physiology, and the therapeutics of the jaws or masticatory system and the teeth as they relate to the health of the whole body, including applicable diagnostic, therapeutic, and rehabilitation procedures." 1 The glossary of prosthodontic terms. 7th ed. J Prosthet Dent. 1999; 81: 71 Google Scholar Many gnathologic research endeavors have added much to our knowledge and understanding of the stomatognathic system, particularly those involving chewing (masticatory) kinematics 2 Ahlgren J. Mechanism of mastication. Acta Odontol Scand. 1966; 24: 1-109 Google Scholar , 3 Ahlgren J. Pattern of chewing and malocclusion of teeth: a clinical study. Acta Odontol Scand. 1967; 25: 3-13 Crossref PubMed Scopus (76) Google Scholar , 4 Wickwire N.A. Gibbs C.H. Jacobson A.P. Lundeen H.C. Chewing patterns in normal children. Angle Orthod. 1981; 51: 48-60 PubMed Google Scholar , 5 Gibbs C.H. Masserman T. Reswwick J.B. Derda J.H. Functional movements of the mandible. J Prosthet Dent. 1977; 26: 604-620 Abstract Full Text PDF Scopus (168) Google Scholar , 6 Guttetman A.S. Chop-stroke chewers. Dent Prog. 1961; 1: 254-257 Google Scholar , 7 Sheppard I.M. The effect of extreme vertical overlap on masticatory stroke. J Prosthet Dent. 1965; 15: 1035-1042 Abstract Full Text PDF PubMed Scopus (8) Google Scholar , 8 Alexander T.A. Gibbs C.H. Thompson W.J. Investigation of chewing patterns in deep-bite malocclusions before and after orthodontic treatment. Am J Orthod. 1984; 85: 21-27 Abstract Full Text PDF PubMed Scopus (17) Google Scholar , 9 Gillings B.R.D. Graham C.H. Duckmanton N.A. Jaw movements in young adult men during chewing. J Prosthet Dent. 1973; 29: 616-627 Abstract Full Text PDF PubMed Scopus (52) Google Scholar , 10 Buschang P.H. Hayasaki H. Throckmorton G.S. Analysis of masticatory cycle kinematics: a new methodology. Arch Oral Biol. 2000; 45: 461-474 Abstract Full Text Full Text PDF PubMed Scopus (102) Google Scholar , 11 Throckmorton G.S. Buschang P.H. Hayaski H. Santos Pinto A. Changes in the masticatory cycle following treatment of posterior unilateral crossbite in children. Am J Orthod Dentofacial Orthop. 2001; 120: 521-529 Abstract Full Text Full Text PDF PubMed Scopus (68) Google Scholar , 12 Anderson K. Throckmorton G.S. Buschang P.H. Hayaski H. The effect of bolus hardness on masticatory kinematics. J Oral Rehab. 2002; 29: 289-296 Crossref Scopus (136) Google Scholar , 13 Kiliaridis S. Karlsson S. Kjellberg H. Characteristics of masticatory movements and velocity in growing individuals and young adults. J Dent Res. 1991; 70: 1367-1370 Crossref PubMed Scopus (53) Google Scholar and the early intraoral telemetry studies (to cite only a few). 14 Pameijer J.H. Brion M. Glickman I. Roeber F.W. Intraoral occlusal telemetry. V. Effect of occlusal adjustment upon tooth contacts during chewing and swallowing. J Prosthet Dent. 1970; 24: 492-497 Abstract Full Text PDF PubMed Scopus (25) Google Scholar , 15 Graf H. Zander H.A. Functional tooth contacts in lateral and centric occlusion. J Prosthet Dent. 1963; 13: 1055-1066 Abstract Full Text PDF Scopus (60) Google Scholar , 16 Glickman J.I. Martigoni M. Haddad A. Roeber F.W. Further observation on human occlusion monitored by intraoral telemetry. IADR. 1970; ([abstract 612]): 201 Google Scholar , 17 Pameijer J.H. Glickman I. Roeber F.W. Intraoral occlusal telemetry. 3. Tooth contacts in chewing, swallowing, and bruxism. J Perodontol. 1969; 40: 253-258 Crossref PubMed Scopus (44) Google Scholar Although originally founded on scientific principles, the application of the valid gnathologic research to clinical practice has moved away from these founding tenets. Modern clinical gnathology (vs university-based gnathologic research) has become, for the most part, a pseudo-science based on mechanistic, perfunctory procedures, and instrumentation. There are many contemporary occlusal institutes that clearly have perverse views on gnathology that are not evidence-based. Dr Lysle Johnston 18 Johnston Jr., L.E. Fear and loathing in orthodontics. Notes on the death of theory. in: Carlson D.S. Craniofacial Growth Series. Center for Human Growth and Development; University of Michigan, Ann Arbor1990: 75-90 Google Scholar sarcastically stated that "gnathology is the science of how articulators chew." Myths of orthodontic gnathologyAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 137Issue 2PreviewAfter reading another opinion article by Rinchuse and Kandasamy (Rinchuse DJ, Kandasamy S. Myths of orthodontic gnathology. Am J Orthod Dentofacial Orthop 2009;136:322-9), I was moved to write this letter in hopes that the discussion of orthodontics, occlusion, and TMD could move on to something more constructive. Perhaps the pages of the AJO-DO could be used to focus attention on the areas in this discussion that unite us, not divide us. Perhaps, if we could focus on what is accepted, agreed upon by all concerned, and evidence based, we could work toward developing some guidelines that would be useful to orthodontists, the general orthodontic patient population, and orthodontic patients with TMD. Full-Text PDF Gnathology lessons from a 1969 Oldsmobile engineAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 137Issue 2PreviewIn 1972, my father and I had our heads under the open hood of a 1969 Oldsmobile 442, listening to an idling 500-horsepower 455-cubic inch engine clunk and clatter. We both speculated as to the problem, and, after the tear-down the micrometer showed an extremely worn crankshaft. The noise from the engine of this muscle car was caused by the piston connecting rod slop and the piston hitting the head/valve at the top of the stroke cycle. The engine was out of centric relationship. The piston could travel past its terminal border position; parts were colliding, and eventually the system broke down. Full-Text PDF After 50 years in practice, the evidence is convincingAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 137Issue 2PreviewI have been in active orthodontic practice for nearly 50 years. During this time, I have seen many different theories for "orthodontic gnathology" and TMD diagnosis and treatment, with each guru espousing his own ideas of how things should be and what our goals should be. I wonder, with all this confusion, how practicing orthodontists have managed to do a fairly decent job for all these years. We have obviously been doing something right. Full-Text PDF