CBCT and CAD-CAM technology to design a minimally invasive maxillary expander

Abstract

Background A large number of articles in recent years studying the effects of non-surgically assisted tooth- versus bone-borne maxillary expanders in growing patients have found no significant differences in mid-palatal suture disjunction or even dentoalveolar changes. This suggests the need for new criteria and better use of current technology to make more effective devices and enhance the benefits of conventional treatments. This article describes a titanium grade V computer-aided design/computer-aided manufacturing (CAD/CAM) maxillary expander supported by two miniscrews, along with a 3D printed surgical guide. Methods The first step was to obtain a digitized model of the patient’s upper maxilla. To simplify the process and ensure the placement of the device in a high-quality bone area, the patients’ digital dental cast was superimposed with a cone beam computed tomography (CBCT) scan. Improved resistance to expansion forces was secured through the use of 2 mm-wide miniscrews, long enough for bicortical anchorage. Placement site and direction were assessed individually in order to achieve primary stability. We chose a site between the second premolars and first molars, while the inclination followed the natural contour of the palate vault. A 3D-printed, polyamide surgical guide was designed to ensure the correct placement of the device with a manual straight driver. Results Favorable clinical results were presented with 3D images. We confirmed a mid-palatal suture parallel separation of 3.63 mm, along with a higher palatal volume, as well as increased intercanine and intermolar distance. Segmentation of the facial soft tissue showed an expansion of nasal airways and changes in nasal morphology. Conclusions Digital models, CBCT and CAD/CAM technology, are essential to accomplish the goals proposed in this article. Further studies are necessary to establish safer miniscrew placement sites and insertion angles so as to achieve greater in-treatment stability. Both the clinician and the patient can benefit from the use of current technology, creating new devices and updating traditional orthodontic procedures.

The Use of CAD/CAM Technology in Mandibular Canine Disimpaction: A Case Report

“…The use of buccal shelf TADs eliminates adverse dental and periodontal effects [ 24 ] on anchorage elements during lower canine disimpaction, causes no discomfort or pain during placement and treatment and is compliance-free [ 25 ]. CAD/CAM digital technology, combined with 3D printing, enables the creation of a surgical guide for positioning the miniscrew and the customized devices used for disimpaction with greater accuracy and predictability, ensuring high-quality bone support [ 26 , 27 , 28 ].…”

CAD/CAM design and 3D printing of a personalised rapid palatal expander for maxillary transverse deficiency

“…9 While MARPE can effectively open the mid-palatal suture in adults after the closure of the mid-palatal suture has occurred, 2 averting the need for orthognathic surgery, prefabricated MARPE appliances impose limitations such as inadequate palatal adaption and difficulty in optimising the position, depth, and direction of the mini-implant. 3 The pMARPE appliance was closely adapted to the palatal contour in the relatively narrow palatal vault. Sufficient supporting bone availability is essential to ensure primary stability of the mini-implants.…”

“…The construction process doesn't consider bone quality and dimensions at the planned insertion sites as 3-dimensional (3D) bone imaging is not incorporated, which can compromise the accuracy of mini-implant insertion, leading to loss of anchorage. 3 Besides, the morphology of the palate can vary widely across individuals and the prefabricated expanders might insufficiently adapt to the palate, especially in high and narrow vault cases. The suitability of prefabricated expanders for patients with narrow palatal vaults has thus been questioned, considering the likelihood of miniimplant deviation or tipping and the consequent risk of failure of palatal expansion.…”

Can computer-guided surgery help orthodontics in miniscrew insertion and corticotomies? A narrative review

“…The CAD/CAM technology allows the clinician to design and plan everything in a single visit, while the 3D printed surgical guide allows the positioning of the miniscrews or the miniscrews together with the device on the same day, confirming their precise position according to the digital planning. The accuracy of this technique is discussed by Cassetta et al and Sánchez-Riofrío et al who highlighted that it lacks a “learning curve” effect, thus making it a simple procedure with a very low risk of failure ( 20 , 21 ). CAD/CAM technology can therefore help less experienced clinically-surgical operators in safely positioning the miniscrews.…”