The Practice of Modern Orthodontics: History and Evolution History

In the past, orthodontic treatment has been focused mainly on juvenile and adult treatment. Treatment options for patients in these age groups often are limited by complex dental and orthodontic problems and the lack of sufficient future craniofacial growth. During the later part of the 18th century, orthodontic treatment of Class II malocclusion was limited primarily to retraction of the maxillary anterior teeth to decrease excessive over jet.

History has it that in 1880, Norman Kingsley published a description of techniques for addressing protrusion. He was among the first to use extra oral force to retract the maxillary anterior teeth after extraction of the maxillary first premolars; the extra oral force was applied with headgear. Later, Case continued to refine these methods. Angle’s classification of malocclusion, published in the 1890s, provided a simple definition of normal occlusion and was an important step in the development of orthodontic treatment. Angle opposed the extraction of teeth and favored the preservation of the full dentition. His position against tooth extraction led him to depend on extra oral force for the expansion of crowded dental arches and retraction of the anterior segment. Later he discontinued the use of extra oral force and advocated the use of intraoral elastics to treat sagittal jaw discrepancies.

Because of Angle’s dominating belief that treatment with Class II elastics was just as effective as extra oral force, the use of headgear was abandoned by the 1920s. Then, in 1936, Oppenheim reintroduced the concept of extra oral anchorage, employing extra oral traction to treat maxillary protrusion. Accepting the position of the mandible in Class II malocclusions, Oppenheim attempted to move the maxillary dentition distally by employing a combination of occipital anchorage and an E-arch, allowing the mandible to continue its growth.

This resulted in an improved relationship with the opposing jaw. In 1947, Silas Kloehn reintroduced extra oral force, in the form of cervical headgear, for the treatment of skeletal Class II relationships. In 1944, another student of Angle’s, Charles Tweed, was discouraged by the prevalence of relapse in many of his patients treated without extraction, so he decided to oppose the conventional wisdom of non-extraction. In the early part of the 20th century, there was optimism about the influence of orthopedic force on skeletal growth. An almost universal belief was that orthodontic forces, if applied to the growing face, could alter the morphologic outcome.

In the United States, headgear was the principal appliance used for facial orthopedic treatment, whereas in Europe the functional appliance was predominantly used. In 1941, Alan Brodie, one of Angle’s students, concluded that the growing face could not be significantly altered from its genetically predetermined form and that the only option for the orthodontist in cases of skeletal malocclusion would be dental camouflage, or the movement of teeth within their jaws. This idea led to tooth extraction.

Evolution

Over many years of teaching and practice, in both pediatric dentistry and orthodontic departments, the author became interested in conducting a retrospective evaluation of patients who were referred for some type of orthodontic problem and who had previous panoramic radiographs available. This retrospective evaluation led to the conclusion that the longitudinal monitoring of panoramic radiographs during the mixed dentition is a very valuable, easy technique that enables detection of developmental anomalies during the transitional dentition.

Today the doctors strongly recommend this easy and very useful technique to all practitioners, especially pediatric dentists and orthodontists. The transitional dentition is one of the most critical stages of the dentition, and many eruption problems, whether hereditary or environmental, emerge during this stage. Longitudinal panoramic radiograph monitoring is a careful serial monitoring technique that any practitioner can perform for young patients during transitional dentition to watch for developmental anomalies that may arise at these ages.

The technique the author recommends is to take one panoramic radiograph when the patient is around the age of 6 years during the eruption of the permanent first molar and then two more panoramic radiographs at 8 and 10 years of age. Careful comparison of two or three consecutive radiographs of a patient at this stage of the dentition can easily reveal any abnormal developmental processes emerging between radiographs and therefore can enable early detection and intervention. The following cases illustrate the advantages of longitudinal monitoring of panoramic radiographs and proper intervention.

Panoramic radiographs

The panoramic radiograph is a common diagnostic tool in today’s dental practice. It is a kind of radiograph that provides a full picture of the dentition and the complete maxilla and mandible. Panoramic radiographs do not show the fine detail captured on intraoral radiographs and are not as specific as other intraoral radiographs, but in a single radiograph it provides a useful general view of all dentition, the maxilla and mandible, the sinuses, and both TMJs. This type of radiograph is very useful, especially during the mixed dentition, for early detection and prevention of all problems disturbing the normal development of occlusion. Especially during the mixed dentition as a diagnostic tool for early-age orthodontic treatment, the following are important aspects that should be carefully evaluated on a panoramic radiograph before any orthodontic treatment:

  • Position and pattern of fully emerged as well as emerging permanent teeth
  • Sequence of permanent tooth eruption
  • Comparison of crown height levels on the left and right sides
  • Obstacles preventing eruption
  • Abnormal tooth malformations (gemination, fusion, dens in dente, or dilaceration)
  • Exfoliation and pattern of primary teeth root re-sorption
  • Tooth number and supernumerary teeth or congenitally missing teeth
  • Eruption problems, such as impaction, transposition

Technology in the Modern Practice of Orthodontics

The integration of technology is essential to the success of any orthodontic practice seeking to increase efficiency and communication. The globalization of all aspects of society, including orthodontics, allows us to now have access to the best resources available to deliver high quality orthodontic treatment in our own communities. The Unite Treatment Management Portal (TMP) is a complete software solution to integrate digital model storage, orthodontic treatment planning, and customizing the Incognito™ and Incognito Lite Appliance Systems for your patients. Unitek TMP enhances the ability of the orthodontist to diagnose and treatment plan cases using the high resolution graphics and model analysis measurements. Communication tools allow the orthodontist to interact with the 3M Unitek lab using emails, annotation boxes, and images.

Digital model storage is progressively being adopted by many orthodontic offices as a method to reduce stone model storage needs, increase communication with patients and other dental professionals, and improve treatment planning for the orthodontist. In our practice, we decided to start digital right from the start-up in order to take advantage of these benefits. After testing several of the digital model systems on the market, we chose the Unitek TMP software system for all of our model needs. The system scans the actual orthodontic impression instead of a stone model poured from the impression which helps eliminate possible errors obtained during the stone model fabrication. The advantages of the Unitek TMP system for model storage are its superior detail in model fabrication, ease in communication with 3M Unitek support, and management of patient files including integration with practice management software.

One of the biggest advances in modern orthodontics is the utilization of technology to deliver customized brackets, wires, and treatment forecasts to enhance patient results through more effective and efficient treatment methods. The other big push in the field of orthodontics is patient’s desire for aesthetic or “invisible” orthodontic treatment, especially as more adults seek care. After studying all the “customized” orthodontic systems on the market, we found that only the Incognito Appliance System can truly deliver all three levels of customization and aesthetics. Lingual orthodontics also has the advantage of eliminating the incidence of labial decalcifications during orthodontic treatment.

The Incognito System begins with an accurate two-phase PVS impression and bite registration that you will send to the lab. Unitek TMP replaces the need for traditional paper lab forms to be mailed with the case and allows total digital customization and effective communication with 3M Unitek. Digital photographs can also be uploaded from practice management software to allow enhanced communication. The custom prescription for the brackets, wires, and all treatment planning goals are entered to ensure full utilization of the Incognito system.

The orthodontist first chooses all customized treatment objectives for the patient’s case including: occlusal, aesthetic, and alignment considerations. Next, the custom fixed appliances are carefully selected from a library of brackets, bands, and additional attachments. The visual cues now available with the Unitek Treatment Management Portal (TMP) system allow the orthodontist to see the full scope of the setup and rotate the template. Then, the wire sequence is selected from an array of wire sizes and materials with a “Wire Sequence Guide” to aid in case specific considerations.

The Incognito system lab then sets up the case using these specifications and taking into account anatomical and biological limitations. The case is mounted on an articulator and the setup is digitally scanned and placed in Unitek TMP for review by the orthodontist. The enhanced communication tools now available in Unitek TMP allow visual cues and measurements to be used to create the most accurate representation of the orthodontist treatment goals. Advanced features like the “overlay” button give the user visualization of initial versus final setup in all planes of space.

The power of the technology behind Unitek TMP and the Incognito Appliance System truly shows in the digital setup and fabrication of the 100% customized brackets and wires. CAD/CAM software is used to construct the pattern for each individual bracket taking into consideration anatomical and access considerations based on the prescription specified by the orthodontist. Once the case is setup to the final result, the wires are then constructed to achieve the required mechanics. All the necessary archwire bends are determined in the CAD/CAM software and bent robotically to ensure precision. Using this method, movement towards the final position of the teeth is achieved from the first wire through the entire wire sequence. Throughout the entire setup and fabrication process, communication between the lab and orthodontist is available through messaging within TMP. Utilizing current technology, the Unitek TMP system integrates digital models, customized wires and brackets, and digital treatment planning and setup in an interactive format to achieve maximum patient results.

Development of supernumerary teeth can occur any time during the primary dentition, mixed dentition, and the permanent dentition. They are almost always harmful to adjacent teeth and to the occlusion. Most cases of supernumerary teeth are asymptomatic and are usually found during routine clinical or radiologic investigations. Early recognition of treatment planning for supernumerary teeth is important components of the preliminary assessment of a child’s occlusal status and oral health, which is based on careful clinical and para-clinical examinations.

When assessing supernumerary teeth in the developing occlusion of a child, the clinician must consider the number, size, and form of teeth, the eruption time, the sequence of eruption, the position of each tooth, and local and general factors that can affect occlusion during transitional changes. The following are clinical signs of the presence of supernumerary teeth:

  • Abnormal pattern and abnormal sequence of eruption
  • Delayed eruption
  • Absence of eruption

Another kind of eruption disturbance is tooth transposition, or positional interchange of two adjacent teeth, especially their roots. Tooth transposition is a rare but clinically difficult developmental anomaly. Depending on the transposed teeth and their position, normal eruption of adjacent teeth can be affected, root anatomy can be damaged, and eruption of the affected teeth can be delayed. This eruption disturbance was first defined in 1849 by Harris, who described tooth transposition as an “aberration in the position of the teeth.” Transposed teeth are classified into two types of tooth displacement: complete transposition and incomplete transposition.

In complete transposition, both the crowns and the entire root structures of the involved teeth are displaced to abnormal positions. In incomplete transposition, only the crown of the involved tooth is transposed, and the root apices remain in place. Transposition is sometimes accompanied by other dental anomalies, such as peg-shaped lateral incisors, congenitally missing teeth, crowding, over retained primary teeth, dilacerations, and rotation of adjacent teeth. Displacement of one tooth from one quadrant across the midline to the other side of the arch has very rarely been reported. These types of anomalies should be considered ectopically erupted teeth, not transposed teeth.

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