Corrective orthodontics is the use of full orthodontic appliances in the permanent dentition to treat a malocclusion in either adolescents or adults. Typical corrections in AP plane include Class I (Video 3) crowding or spacing, Class II (Video 4), and Class III (Video 5) correction. Other types of correction include closing an open bite (Video 6), correcting a deep bite, or expanding the maxillary arch to correct a crossbite (Video 7). In cases with moderate to severe crowding, teeth may need to be extracted to create space. Extraction patterns can vary, including upper first premolars, a combination of premolars in the four quadrants, or even a lower incisor. Determining an extraction pattern is based on a variety of factors the orthodontist considers.
In the past 2 decades, orthodontics has seen a huge shift in patient types and preferences. About 30% of patients are adults with more specific expectations from orthodontic treatment. Patients of all ages expect esthetic options for orthodontic treatment. In response to these evolving attitudes, more esthetic alternatives to the metal brackets have been developed. Ceramic brackets provide a clear alternative that can be used with clear or opaque elastic ties. Esthetic wires and steel ties are also becoming more common. With these brackets, metal wires and ties may still need to be used. Another bracket option is lingual braces, which requires great skill from the treating orthodontist. Advancements in ceramic and lingual braces continue to occur and these systems continue to improve.
Another option for esthetic orthodontics is clear aligner therapy. A number of companies and laboratories now exist that fabricate clear aligners for orthodontic treatment. The most widely used is the Invisalign® system by Align Technology, Inc. Impressions made using an intraoral scanner (iTero scanner) or polyvinyl siloxane material are provided and a series of custom made, clear, removable appliances are fabricated to sequentially move teeth. SmartTrack plastic, a proprietary plastic developed by Align Technology, and composite attachments on the teeth are simultaneously used to move teeth. Orthodontic treatment using Invisalign® has improved greatly over the years, and can now be used with a variety of malocclusions and treatment options. It is important for the practitioner using Invisalign® to fully understand its principles, as well as those behind orthodontic tooth movement in general, to be able to use the system properly and to its full capacity. The best outcomes are seen when patients are compliant, wearing aligners for a minimum of 22 hours per day.
Tissue Considerations and Oral Hygiene during Orthodontic Treatment
Oral hygiene is of paramount importance during orthodontic treatment. The role of dental plaque accumulation in the development of dental caries and periodontal diseases is well documented. While orthodontic appliances do not cause dental caries, they provide increased possibilities for the retention of food debris and plaque. The unwanted effects of enamel decalcification, white spot lesions, and gingival inflammation can be prevented if good oral hygiene is followed. Orthodontic appliances encourage accumulation of microbial flora and food residues and make good oral hygiene much more challenging. Various toothbrush devices, mouth rinses and other home care products are available to help the patient achieve optimum oral hygiene. This added plaque accumulation, in addition to the appliances, can stain patients’ teeth, and many patients choose to whiten their teeth after orthodontic treatment for more esthetic results.
Once the malocclusion is corrected and the braces are removed, patients enter the retention phase of orthodontics. Once out of orthodontic treatment, the gingival fibers tend to pull teeth towards their original positions. Retainers serve to hold the teeth and prevent this from occurring. Options for retainers include removable and fixed. Patients are advised to wear the retainers for a certain number of hours daily, and cooperation is very important in order to maintain the results of orthodontic treatment. Common removable retainers include Hawley-type retainers, made of acrylic and wire, and clear, or Essix, vacuum-formed retainers. Other unique retainers also exist for specific malocclusions and retention needs.
Fixed retention usually consists of a bonded wire to the lingual of the incisors. The most commonly fixed lingual retainers are for the mandibular canines and incisors, and can be bonded to only the canines or to each tooth. The initial presentation of the dentition and the orthodontic movements that occurred in treatment are used to determine the best option for the patient. Bonded retention can also be used in the maxillary arch in cases with midline diastemas or severe rotations. While bonded retainers require less patient cooperation, they require increased oral hygiene measures to maintain the cleanliness and periodontal health of the teeth bonded.