Infrazygomatic crest screws in the Invisalign treatment of an adult Class II division 1 patient

Class II malocclusion in adult patients is challenging to treat and can require extraction, a long treatment time and a high level of compliance in wearing Class II elastics. Clear aligners can be a useful tool to treat Class II patients without extraction since they provide efficient control of tooth movement during distalisatio?n, but they also usually demand a long treatment time and a very high level of compliance. When treating Class II division 1 patients, it is necessary to manage incisor inclination during the retraction phase to prevent premature contacts that can lead to a posterior open bite. Generally, when treating Class II malocclusion using a distalisation protocol, Class II elastics need to be worn over the entire treatment period to create proper anchorage for posterior distalisation and prevent any side effects that may be caused by this method. The present case report illustrates the treatment of a Class II hypodivergent case with Invisalign aligners (Align Technology, San Jose, CA, USA) in an adult patient in which distalisation and compliance were facilitated by means of infrazygomatic crest screws positioned only in the molar areas after 4 months of treatment, thus eliminating the need for compliance in wearing Class II elastics for the majority of the treatment period. The digital setup was programmed to achieve sequential distalisation of the maxillary first and second molars, then ?infrazygomatic crest screws were inserted and 50% sequential distalisation followed in the maxillary second premolars, then en masse retraction from the maxillary left first premolar to the maxillary right first premolar began. Distalisation was combined with anterior intrusion following smile arc exposure and the treatment was completed in 18 ?months. The present approach for Class II treatment with severe protrusion, which involves combining sequential distalisation for the first part of the treatment until the molars achieve Class I occlusion and then insertion of infrazygomatic crest screws to create skeletal anchorage in the posterior molar area before starting the en masse retraction of the anterior teeth, seems to be effective for correcting Class II malocclusion, ensuring good posterior anchorage control and decreasing the overall treatment time and the need for compliance in using maxillomandibular elastics.