Читать книгу Biological Mechanisms of Tooth Movement - Группа авторов - Страница 19

The writings of authors in the Middle Ages were mainly repetitions of what already existed, and there were no new references to mechanical principles for correcting dental irregularities. It was Pierre Fauchard (1678–1761), the father of dentistry and orthodontics (Figure 1.4), who organized previous knowledge and opinions, and provided an extensive discussion on the rationale for numerous clinical procedures (Wahl, 2005a). His book titled Le chirurgien dentiste (The Surgeon‐Dentist) was published in two editions, the first in 1728 and the second in 1746. The second edition described a few orthodontic cases (Volume II, Chapter VIII) along with an extensive description of appliances and mechanical principles. This book is considered to be dentistry’s first scientific publication. Fauchard also advocated keeping young patients under observation and removing long‐retained deciduous teeth to prevent irregularity in the permanent dentition. He also stated that blows and violent efforts may increase the chances of developing an irregular tooth arrangement and reported that the greatest incidence of these mishaps occur in the incisor and canine regions. Most of the appliances he fabricated were made of gold or silver and were designed according to the patient’s needs, marking the beginning of “customized orthodontic appliances” (Figure 1.5). The orthodontic appliance described by Fauchard used silk or silver ligatures to move malposed teeth to new positions, and “pelican” pliers for instant alignment of incisors, facilitated by bending of the alveolar bone. After placing teeth in position with pelican forceps, he retained them with silver ligatures or lead plates adjusted on either side, over which linen was placed and sewed into position with needle and thread, between interproximal spaces and over the occlusal surfaces of the teeth. This device, named bandeau, marked the beginning of the era of modern orthodontic appliances and their utilization in treating malocclusions (Asbell, 1990).

Figure 1.4 (a) Pierre Fauchard (1678–1761), the father of dentistry and orthodontics.

(Source: Vasconcellos Vilella, 2007.)

(b) His book titled Le chirurgien dentiste(The Surgeon‐Dentist).

(Source: Picture courtesy: Andrew I. Spielman.)

Figure 1.5 (a) Dental pelican forceps (resembling a pelican’s beak).

(Source: Courtesy of Alex Peck Medical Antiques.)

(b) Bandeau–the appliance devised by Pierre Fauchard.

(Source: Vasconcellos Vilella, 2007.)

John Hunter (1728–1793), in 1778, in his book titled A Practical Treatise on the Diseases of the Teeth, stated that teeth might be moved by applied force, because “bone moves out of the way of pressure.” This book, along with his previously published book, titled The Natural History of Human Teeth, marked the beginning of a new era in the practice of dentistry in England (Wahl, 2005a). Hunter recognized the best time to carry out orthodontic treatment to be the youthful period, in which the jaws have an adaptive disposition. In 1815, Delabarre reported that orthodontic forces cause pain and swelling of paradental tissues, two cardinal signs of inflammation.

Up to 1841, about a century after Fauchard had written a chapter about orthodontics, there was no single book devoted entirely to orthodontics alone, but in 1841, Schange published a book solely confined to orthodontics (Wahl, 2005a), which served as a stimulus for conducting investigations in this defined clinical field. Moreover, this book initiated the notion that orthodontics is a unique dental specialty. Schange described the tooth‐eruption process, causes of irregularities, their prevention, and classified defects of conformation. In treating irregularities, Schange took a different view from Fauchard, who had advocated the use of radical procedures. He warned practitioners of the attendant danger to the tooth when these procedures were performed and favored application of delicate forces in a continuous manner, hence being the first to favor light orthodontic forces. He recommended silk ligatures to apply light forces, and gold for constructing bands and plates, and recognized the importance of retaining teeth after OTM.

Figure 1.6 Norman William Kingsley (1829–1913).

(Source: Dr Sheldon Peck, University of North Carolina at Chapel Hill. Reproduced with permission of Dr Sheldon Peck.)

Samuel Fitch’s book titled A System of Dental Surgery, published in 1835, marked the beginning of a new era in the practice of dentistry in America. He drew attention to the mobility of teeth within the alveolar process during OTM and characterized the growth period as the time for attaining best results of treatment. Norman Kingsley’s treatise on “oral deformities” (1880) had an immediate impact, by placing orthodontics as a specialty, which requires more than general information to solve many of the problems its practitioners face. The book emphasized the importance of basic biology and mechanical principles while studying orthodontia as a science. While describing structural changes due to tooth‐moving forces, Kingsley (Figure 1.6) stated that “the physiological fact being that bone will yield or become absorbed under some influences, and also be reproduced … and in moving teeth, the power used creates a pressure which produces absorption.” He also stated that “the function of absorption and reproduction may or may not go coincidentally, simultaneously and with equal rapidity.”

The article published in Dental Cosmos by John Nutting Farrar in 1887 titled “An enquiry into physiological and pathological changes in animal tissues in regulating teeth” stated that “in regulating teeth, the traction must be intermittent and must not exceed certain limits.” He also stated that the system of moving teeth with rubber elastic is unscientific, leads to pain and inflammation, and is dangerous to future usefulness of the teeth. He tried to describe optimal rate of tooth movement as 1/240 inch twice daily, in the morning and the evening, and stated that at this rate, tooth movement will not produce any pain or nervous exhaustion. He stated further that the tissue changes with this procedure are physiological, but if the rate exceeds this range, the tissue reactions will become pathological. His work, which appeared as a series of articles in Dental Cosmos from 1876 to 1887, was summed up in his book titled A Treatise on Irregularities of The Teeth and Thier Correction published in 1888 (Figure 1.7). In this book he devoted a large section to fundamental principles behind orthodontic mechanics and to the use of various mechanical devices (Asbell, 1998). Farrar, the “Father of American Orthodontics,” was credited with developing the hypothesis that rated intermittent forces as best for carrying out OTM which led to the introduction of a screw device for controlled delivery of such forces. A remarkable statement by Farrar was that OTM is facilitated by bending or resorption of the alveolar bone, or both. His publications endowed him as the founder of “scientific orthodontics” (Wahl, 2005b).

Figure 1.7 The front page of the book A Treatise on the Irregularities of the Teeth and their Correction by John Nutting Farrar.

(Source: Picture courtesy: https://openlibrary.org.)

Eugene Talbot, in his book titled Irregularities of Teeth and their Treatment (1888) rightly mentioned that “without the knowledge of etiology, no one can successfully correct the deformities as is evident in the many failures by men who profess to make this a specialty.” He argued that every case of malocclusion is different, making it difficult to classify, and proposed customizing appliances suited for each patient. He was the first to use X rays as a diagnostic aid in orthodontics, to identify abnormal and broken roots, locate third molars, and expose absorption of roots and alveolar process due to OTM.