Patients with TMD should be handled with extra care when planning for mandibular anterior repositioning. Although in some cases, a spontaneous repositioning of the condyle can be observed after occlusal interferences have been eliminated with the relief of TMD symptoms,22 such as in cases of condylar resorption where the condylar head becomes superiorly and posteriorly displaced after splint therapy or in cases of Class II Division II deep bite after maxillary incisors have been uprighted,23 it is still not advisable to deliberately position the condyle through orthodontic treatment in order to reduce or eliminate the risk of TMD. While anterior placement of the condyle might be beneficial in certain cases of anterior disc displacement with reduction, simulating the effect of an anterior repositioning splint that captures the displaced disc,24, 25 in other TMD cases, anterior positioning of the condyle may cause more harm owing to the already poor adaptive capacity of the TMJ. Therefore, it is crucial to conduct a thorough TMD examination and screening before commencing orthodontic treatment. It is also important to address any TMD pain before starting orthodontic treatment and to refer the patient to appropriate healthcare professionals, such as oral surgeons, TMJ specialists or other medical professionals, if necessary.
Clinical practice considerations
Another important consideration for clinicians is undesired dental effects produced by repositioning in skeletally mature patients.26 Since the physiological potential of an individual’s glenoid fossa remodelling and condylar adaptation varies greatly, it is likely that unwanted dental tipping and protrusion will occur in individuals who have less adaptability. In such cases, the sagittal improvement in occlusion is more of a dental compensation, which can lead to unfavourable periodontal outcomes and relapse.17, 27 This concern was highlighted in a recent safety alert released by both the US Food and Drug Administration and the American Dental Association regarding certain expanders used in non-growing patients in which the dental effects overshadow the skeletal effect, causing unwanted tooth flaring, uneven bites and even tooth loss.28, 29 Unfortunately, such incidents ended with lawsuits against the inventor of the devices.30
Conclusion
In summary, orthodontic treatment should be based on the latest scientific evidence. When planning mandibular repositioning in adult patients, clinicians need to be cautious in their case selection in order to avoid potential risks that may lead to complaints or lawsuits. It is also important to consider a team approach involving experienced clinicians. Patients should be fully informed and understand the nature of repositioning as an alternative to orthognathic surgery.
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