Dental Tribune Middle East & Africa Edition

by Dr. Derek Mahony Aim E dward H. Angle dominated orth- odontic armamentarium, diagnosis and treatment planning for almost a half century until Charles Tweed successfully challenged his mentor’s non- extraction mantra. The ensuing diagnostic regimen used by Tweed, however, proved to have serious limitations and clearly re- sulted in the extraction of too many teeth. This caused a subsequent deterioration of soft tissue appearances of patients that nei- ther they nor their doctors liked. This ar- ticle will describe and illustrate how new expansion techniques differ qualitatively from those of Angle, and how these tech- niques offer patients and doctors less inva- sive and more comfortable therapies which do not jeopardize facial appearances. Introduction For the first third of this past century, or- thodontics found itself dominated by one man, Edward H. Angle, with the resultant intellectual stagnation that arises from such monomaniacal control. This recognition in no way detracts from Angle’s contributions – notably his clear and simple classification system along with the edgewise bracket. Both of these inventions have endured for a century, and that is no mean achievement in any scientific discipline. Nevertheless, or- thodontists’ unquestioning acceptance of his limited diagnostic and treatment planning regimens hindered the advancement of this discipline more than it helped, and the last half of this past century was spent trying to overcome the stupor of the first half. Angle’s influence continued until an apos- tate student of his, Charles H. Tweed,1 had enough courage and objectivity to challenge Angle’s non-extraction scheme. It wasn’t a tremendous leap of intellectual power. Tweed simply and honestly recognized that when 100% of your patients relapsed, there might be something wrong with the diagno- sis and/or treatment planning. Dr. Tweed acted appropriately in the face of this challenge - quite unlike the ancient dentist who chided a young colleague who was describing his meticulous technique of endodontic filling to the monthly assembly of dentists. The old man explained his own technique that used a simple matchstick sharpened with a pocketknife and then jammed into the canal. When the young dentist asked if a lot of these root canal fill- ings didn’t subsequently fail, the older man replied, “Every damn time!” Dr. Tweed tired of those orthodontic ab- scesses and, unlike his peers, sought to cor- rect the deficiencies he saw in Angle’s phi- losophy. Some would say that he overcor- rected, but that said, we must pay homage to anyone who has the skill and temerity to successfully challenge a mentor and his minions. Tweed’s success brings to mind the remark of C.S. Lewis, who said, “No genius is so fortunate as he who has the skill and ability to do well that which oth- ers have been doing poorly.” Nevertheless, I don’t think that Tweed would have ever been able to deliver his paper describing his extraction technique had Dr. Angle still been alive. Angles in- fluence over the society that bore his name was too immense to permit such hubris from a young upstart. But as Samuelson, the MIT economist, once noted: “Science progresses slowly – funeral by funeral.” And so it was and is in orthodontics. Nonextraction Philosophy Aside from the edgewise bracket and the classification system, Angle’s most endur- ing legacy has been his belief in nonex- traction therapy. Angle had unsuccessful- ly experimented with premolar extractions while using his ribbon arch appliance, but he never solved the problem of parallel- ing the roots to prevent the extraction spac- es from opening. If he couldn’t do it, then, ergo, no one else could, and this resulted in a virulent opposition to any extractions and an insistence upon enlarging the arches to accommodate all of the teeth. This dogma stayed dominant for sever- al decades until Tweed advocated the ex- traction of premolars based on his diagnos- tic triangle, which was the first systemat- ic treatment planning stratagem orthodon- tists had. Tweed received corroboration si- multaneously from another former Angle protégé in Australia, Raymond Begg,2 who had studied aborigines and concluded that nature intended for enamel to wear. He de- cided that orthodontists could mimic na- ture by extracting teeth prior to orthodon- tic therapy. The Tweed and Begg Extrac- tion Philosophies eventually prevailed and remained uncontested for some time. Several years past before Holdaway3, 4 pub- lished his articles that suggested the soft tis- sue as the determining feature of diagno- sis. This disputed Tweed’s narrow diagnos- tic regimen that focused on the mandibular incisor and totally neglected the soft tissue. Tweed’s triangle set in motion a trend that emphasized more prudence in the extraction of teeth. Soon others added their discoveries regarding soft tissue and the maxillary inci- sors as main determinants of diagnosis and treatment planning.5-7 From the inception of this specialty, with Dr. Angle, diagnosis never had too much importance because everyone received the same nonextraction treatment with the same expansive appliance. The marvel of it all is that the collection of orthodon- tic records never became important. A few months ago an orthodontist boasted that since invoking a different treatment regi- men, he was treating 98% of his patient’s nonextraction. One was tempted to ask if he still took records because with diagnos- tic certainty such as that, records are clearly redundant. Orthodontists shouldn’t waste patients’ time and money taking impres- sions, cephalometric X-rays or doing treat- ment simulations if all treatment plans are essentially the same. One doesn’t need orthodontic records to come to such a pre- conceived conclusion. Obviously, this one-size-fits-all treatment planning didn’t benefit patients a hun- dred years ago, and it doesn’t in our own age. But such simplicity continues to hold enormous appeal for many orthodontists. Orthodontists pride themselves in be- ing scientists, and without doubt they re- ceive good training in the scientific meth- od; but it takes very little anecdotal infor- mation to eclipse the scientific judgment of many in the profession. Albert Szent- Györgyi was probably more right than he knew when he said, “The brain is not an organ of thinking but an organ of surviv- al like a claw and fang. It is made is such a way as to make us accept as truth that which is only advantage.” No matter how spectacularly orthodontic therapy changes, it will benefit our patients minimally if we do not have a concomitant improvement in our diagnostic and prog- nostic knowledge. This remains the num- ber one imperative for those who practice orthodontics. Orthodontists should view any new therapy unaccompanied by equal- ly sophisticated diagnostic knowledge sus- piciously. Patients have already received far too much orthodontic treatment and far too little diagnosis. Instrumentation The first attempts to correct malocclusions used simple large arch wires ligated to the malposed teeth. Pierre Fauchard of France developed the precursor of the modern ap- pliance – expansion arch (Figure 1). Figure 1: Fauchard’s expansion arch This arrangement gave only tipping con- trol, in one dimension, and soon proved in- adequate for controlling rotations. In 1887 Edward H. Angle introduced the E arch, i.e. expansion arch that used a labial wire supported by clamp bands on the molar teeth which ligated to the other teeth (Fig- ure 2). Figure 2: Angle’s E Arch Metallurgical developments by the early 20th Century allowed clinicians to encase all of the teeth with bands and solder at- tachments that could control the horizon- tal rotations. Angle developed a popular attachment known as the pin and tube at- tachment in 1911 (Figure 3), and it satisfied many of the requirements of clinicians; but this demanded unusual dexterity, patience and skill, so dental clinicians evolved to a ribbon arch bracket (Figure 4), which Angle introduced in 1916. It provided good con- trol in two dimensions and became pop- ular quickly. The ribbon arch attachment also marked the first time orthodontic at- tachments gained the name bracket.8 Figure 3: Pin and tube appliance Figure 4: Ribbon arch When Angle launched the ribbon arch bracket, he had already started work on the edgewise bracket primarily as a supple- ment to his ribbon arch appliance. Never- theless, the edgewise bracket did not sud- denly spring full-grown from Angle’s fer- tile mind, but slowly evolved with sever- al iterations (Figure 5). When Angle real- ized that this bracket could deliver three- dimensional control of the teeth with hor- izontal, one directional placement and si- multaneous engagement of all the teeth, he changed the bracket several times until he achieved the #447 (Figure 6) in 1928. It re- ceived early and enthusiastic endorsement How We Got from There to Here and Back 20 Dental ortho tribune Dental tribune Middle East & Africa Edition | March-April 2013