G-Block: Posterior anchorage device tads-supported after molar distalization with aligners: An adult case report

Temporary anchorage devices represent a fundamental tool to reliably manage orthodontic anchorage in several conditions. One of the most recent application is represented by the combination of aligners with TADs to simplify specific movements such as posterior intrusion, anterior intrusion, molars distalization. The objective of this case report is to show a novel technique called "G-block" to manage posterior anchorage with a hybrid approach combining aligners and TADs.

This case report shows a Class II malocclusions (end to end relationship) with increased overjet and incisors proclination treated with aligners and maxillary distalization approach. To manage the posterior anchorage after second molar distalization and to avoid the use of Class II elastics, TADs (Spider Pin 1.3mm×10mm) were inserted into the interradicular space between the maxillary first and second molars following second molar distalization. The mini screws were used to provide both direct and indirect anchorage. The second molars were connected to the TAD by means of a 0.18 SS wire embedded in the attachment and blocked to the head of the mini-screw for indirect anchorage, while an elastic chain connecting the TADs to the buttons bonded to the first molars and premolars provided direct anchorage during first molar and premolar distalization.

A solid bilateral Class I occlusion was achieved with a normal overjet and overbite. The dental arches were well aligned and leveled with good intra-arch symmetry and regular arch forms. Final cephalometric analysis showed a significant change in upper incisor proclination (15̊ reduction) while maintaining correct torque control and a significant change in molar relationship. The aesthetic analysis showed an improvement in lip competence and incisor exposure.

The use of TADs for posterior anchorage after maxillary molar distalization with aligners, could represent an effective solution to easily manage the posterior anchorage reducing the need for patient's compliance in using elastics and in particular simplifying the posterior teeth movements by coupling the force expressed from the aligners with the force expressed by the auxiliary system.