11 August 2021

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Palatal miniscrew insertion using a CAD-CAM surgical guide: a case report

Authors: Michele Cassetta, Federica Altieri, Rosanna Guarnieri, Gabriella Padalino, Martina Mezio, Ersilia Barbato

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OBJECTIVES: The aim of the present case report is to describe an orthodontic treatment to gain space in the maxillary arch by using a bone-anchored molar distalization appliance (distal-jet). Computer-guided palatal orthodontic mini-screws were inserted in the palatal vault thanks the use of a surgical guide realized with CAD/CAM technology.

MATERIALS AND METHODS: In this case report two orthodontic mini-screws were inserted in the palatal area by means of a surgical guide by a specialist in orthodontic without oral surgery or computer-guided skills. For the surgical guide fabrication, the patient performed a CBCT exam wearing a radiological tray; the same radiological fork was also used during the dental cast scanning. The STL files of the maxillary bone and the digital dental cast of arches were matched thanks to a dedicated software. The appropriate miniscrew insertion sites were planned on 3D images created by the fusion of CBCT and dental digital model images. The ideal placement site was determined on the basis of the width and thickness of the palatal vault; moreover, the correct length and diameter of the miniscrews were choosen. Using the same software, the surgical guide was designed (CAD phase) and subsequently manufactured using a 3D printer (CAM phase). In the same day after the miniscrews insertion under local anesthesia, the molar distalization device was applied and activated. The orthodontic appliance was monthly activated until reaching the I class molar relationship.

RESULTS: The molar distalization phase to gain the space in the maxillary arch was 8 months. The miniscrew stability was preserved during the entire orthodontic treatment. No peri-implant tissues inflammation was recorded during the monthly checks. A I class molar relationship was achieved.

CONCLUSIONS: The computer-guided insertion technique of palatal orthodontic miniscrews can be used by inexperienced clinicians successfully. The use of temporary skeletal anchorage devices allows to achieve the desired therapeutic effects avoiding the typical dental side effects of conventional orthodontics appliances.

CLINICAL IMPLICATIONS: Nowdays orthodontic miniscrews are auxiliary means of traditional orthodontic appliances used in order to accelerate orthodontic therapy, to simplify the procedures commonly used for anchoring control and to avoid the typical dental side effects of conventional orthodontics appliances. .The use of miniscrews for skeletal anchorage, allowed the simplification of many orthodontic procedures conventionally employed for anchorage control, providing new resources in orthodontic treatment. New techiniques are developed to provide predictable and good quality results. With the use of image guided planning software,  it is possible  to plan the  ideal miniscrew placement site. Thanks to three-dimensional imaging techniques (CBCT) and dedicated softwares, a surgical guide can be designed and manufactured using a 3D printer. Thanks to this computer-guided insertion technique of palatal orthodontic miniscrews also inexperienced clinicians can achieve predicable results.