Tarek El-Bialy, Donna Galante, Sam Daher
This chapter highlights the important features of clear aligners and their possible added benefit to orthodontic treatment. In particular, clear aligners disarticulate the teeth and this disarticulation makes it easy to achieve inter-arch tooth movement than with regular fixed orthodontic appliances. This chapter presents different features of clear aligners that may make tooth movement easier than fixed orthodontic appliance.
* Corresponding author Tarek El-Bialy: Faculty of Medicine and Dentistry 7-020D Katz Group Centre for Pharmacy and Health Research University of Alberta, Edmonton, Alberta T6G 2E, Canada; E-mail: email@example.com.
As mentioned earlier in chapter 2 (Science and practice of clear aligners), the type of plastic that has been used to fabricate the clear aligners may have piezoelectric property which, if proven for new plastic materials, can be utilized for faster tooth movement and minimum orthodontically induced root resorption. There are other features that clear aligners may actually provide advantages over regular orthodontic braces. These features, from the author’s prospective can be summarized as follows:
- Clear aligners could be described as a short cut to predictable results compared to trial and errors when using regular braces. In other words, driving around the mountain takes longer time than taking a jet from point A to point B without hassling around the mountains. In other words, the digitally planned estimated end point (results or occlusion) can be predicted using the digital treatment plan (Clincheck for example in the case of Invisalign technology). The clinician can predict and expect how the treatment results would be wheth-
er the patient is compliant and the patient’s biological response to tooth movement is within the normal range.
- Clear aligners allow the patients to eat sticky or hard food and better oral hygiene compared with traditional fixed orthodontic braces when patients are not allowed to eat any sticky or crunchy foods throughout the treatment otherwise brackets/tubes can be at a high risk of being broken and this would hurdle the treatment progress and might cause gum/check irritation by the broken brackets or displaced orthodontic wires due to the broken brackets. In addition, with regular fixed orthodontic braces, patients have to do meticulous tooth brushing and dental flossing around the wires and brackets/wires to minimize possible enamel decalcifications and/or periodontal disease from accumulated dental plaque around the gingival margins or in the interdental spaces if not cleaned 100%.
- In cases of noncompliant patients, especially with retainers wear after finishing orthodontic treatment, if relapse occurs, the patient less likely requires new aligners. In the case of using fixed braces, new regular braces might be used. In fact, most likely, relapsed clear aligner cases may be able to re-use their old aligners that can reprogram their treatment towards the initially planned finished occlusions.
- Clear aligners cover the occlusal surface of the teeth which provides many advantages that can be summarized as follows:
- In deep bite cases, with most likely strong musculature, tooth movement is usually restrained or difficult to achieve due to the inclined planes of posterior teeth occlusal cusps. With clear aligners, the occlusal coverage disengages the occlusion that allows for free teeth movement. It can also act as a jaw positioning splint when centric occlusion and centric relationships are not coincident.
- In open bite cases, the occlusal coverage of the posterior teeth by clear aligners works as posterior bite plate/block that can help in controlling the vertical dimension, especially when this is combined with anterior vertical pull chin cup.
- In cross bite cases, the occlusal coverage of the teeth disengages the occlusion to allow easy movement of the teeth from cross bite to normal bite and this occlusal coverage works as a posterior bite plate that has long been used with removable and fixed orthodontic appliances.
- Finally, the occlusal coverage of the posterior teeth is very important in class II cases with or without molar distalization as:
- In cases where molar distalization is required, occlusal coverage of posterior teeth disengages the occlusion and allows for free distal movement of upper posterior teeth.
- It helps control vertical dimension and may help intrude posterior teeth, which when occurs can lead to auto-forward rotation of the mandible and consequently helps in class II correction.
- Clear aligners are more hygienic and less gingival or periodontal problems are encountered with clear aligners when compared to either buccal or lingual fixed orthodontic appliances [1, 2].
- The improved gingival and periodontal health can also help decrease pain with clear aligners compared to fixed orthodontic treatment .
- Finally, in author’s opinion, clear aligners may be used as fluoride application trays should decalcification occur during treatment due to bad oral hygiene.
It should be noted that orthodontic treatment results using clear aligners are mainly dependent on the patient’s wear and compliance with the clinician’s instructions.