Evaluation of Two Mini-Implant Lengths in the Infra-Zygomatic Crest Region

orthodontic mini-implants, also known as miniscrew, implants or temporary anchorage devices, offer an effective panacea for Anchorage loss problem during fixed appliance treatments. Indeed, Mini-implant implantation has become an essential method of controlling anchorage in the clinic and plays an important role in solving some difficult cases, where the integration of orthodontic mini-implants within fixed appliance treatments offers other advantages over conventional anchorage. Intra-radicular micro-implants are placed in between the roots of teeth (mostly) while extra-radicular bone screws are placed away from the roots in the infra-zygomatic areas (IZC) of the maxilla and the buccal shelf areas (BS) of the mandible. Both extra-radicular bone screws and intra-radicular are classified under temporary anchorage devices used for the purpose of skeletal anchorage. Due to the limited space, there is a risk of injury to the roots while using Intra-radicular micro-implants. Therefore, the infrazygomatic crest zone is selected as an alternative implantation site in the clinic. The infrazygomatic crest has a double-layered cortex and is close to the maxillary center of the resistance, which is suitable for implantation and provides strong anchorage. Orthodontic bone screws can be used in almost every clinical situation that a micro-implant is used for, except that they cannot be placed inter-dental purely because of their larger dimension. They can be used for molar uprighting, segmental, and full arch distalization, intrusion of single tooth to full arch, protraction and retraction of dentition and for any other anchorage needs. the two most specific indications would be - full arch distalization of maxillary and mandibular dentition to camouflage a Class II and a Class III malocclusion and for distalization of arches in re-treatment cases of anchorage loss, which are otherwise difficult to be done with a regular micro-implant or time-consuming. However, it is adjacent to the maxillary sinus and tooth roots; therefore, we have to consider many factors, such as bone mass, the thickness of the buccal cortex and the relationship with the maxillary sinus and roots, before implantation in the infrazygomatic crest. Furthermore, previous research by our research group found that it is safe to penetrate the maxillary sinus within 1 mm. This study will be conducted to test the feasibility, reliability of using two different sizes of infrazygomatic mini-implant regarding primary stability, pain perception, sinus penetration, secondary stability, and failure rate.