Orthodontic therapy optionsHow hygienists can provide support for the movement
by Ann-Marie C. DePalma, CDA, RDH, MEd, FAADH
As defined by Wilkins, orthodontics is the area of dentistry concerned with the diagnosis, supervision, guidance, and treatment of the growing and mature dentofacial structures – including conditions that require movement of the teeth – and the treatment of malrelationships and malformations of the craniofacial complex.
As dental hygienists, we are familiar with Dr. Edward Angle's classifications of occlusal relationships. Dr. Angle is considered the "father of modern orthodontics," who designed a classification system in the late 1890s to early 1900s based on the first molar as the key to occlusion. As a review, normal occlusion is considered when the mesiobuccal cusp of the maxillary first molar occludes with the buccal groove of the mandibular first molar. Deviations from this norm are considered malocclusions.
Class I malocculsion has normal molar relationships present, but other teeth may be crowded, rotated, or have excess spacing. In Class II malocclusion, the maxillary first molar is forward of the normal molar relationship so that the mesiobuccal cusp of the maxillary first molar is mesial to the buccal groove of the mandibular first molar. Class II malocclusions are further divided into Division 1 and Division 2. With Division 1, the maxillary incisors are protruding, while in Division 2 the maxillary central incisors retrude and the lateral incisors protrude. Class III malocclusions present with the mesiobuccal cusp of the maxillary first molar distal to the buccal groove of the mandibular first molar. Additionally, occlusal discrepancies including anterior or posterior open bites, increased overbite and overjet, crossbites, and diastemas may be present.
Vital guide to OrthodonticsWhat is the best time to carry out orthodontic treatment?
Although treatment with braces is a large part of what is thought of as orthodontics, monitoring occlusal development and knowing when to perform shorter interceptive procedures, such as a simple extraction, are equally important and may simplify or even remove the need for later treatment with braces. For example, early loss of an upper deciduous canine in the mixed dentition can lead to a shift in the upper centreline to the same side. The timely removal of the deciduous canine on the opposite side of the same arch can lead to spontaneous correction of the centreline without the need for braces. Correction of such a centreline shift in the permanent dentition using fixed appliances can take many months. Similarly, the timely extraction of a deciduous canine where the permanent unerupted canine is becoming ectopically positioned can encourage the latter tooth to erupt into the correct position within the dental arch ( Figs 4a – 4b ). Failure to extract the deciduous canine at the appropriate time in this instance can lead to the permanent canine becoming more ectopically positioned. Treatment then becomes complex, involving surgical exposure and the application of traction to the tooth using a brace over a protracted period of time, and often in the mid to late teens when patients may be less than enthusiastic about wearing braces. Therefore orthodontic assessments should begin earlier than the 11 to 12-year-old age group; indeed they may begin as early as when the teeth first begin to appear in an infant's mouth. It is when the deciduous teeth are being shed and replaced by their permanent successors that short interceptive orthodontic procedures might take place. Full correction of the malocclusion is usually only possible when the permanent teeth have erupted.