An estimated 38% to 50% of patients in modern orthodontic practise have class II malocclusion, making it one of the most prevalent types of malocclusion. Class ll malocclusions can be skeletal, due to maxillary prognathism or mandibular retrognathism, as well as dentoalveolar due to maxillary upper teeth proclination or lower teeth retroclination. There are many clinically proven, effective therapeutic options for treating Class II malocclusion, including headgear, functional orthopaedic appliances, mandibular protraction, conventional fixed appliances with intermaxillary elastics, and a combination of these mechanics with tooth extractions. However, each of these options requires a significant amount of patient cooperation to achieve its true objectives. 

To overcome the factor of patient compliance, TADs were introduced which provide absolute anchorage.

Orthodontic Mini-screws (TADs – temporary anchorage devices) are often used for anchorage in various movements like distalization, retraction, or intrusion.

Various anatomical sites which are present for miniscrew insertion includes palate, infra zygomatic crest, retromolar area and buccal alveolar process of maxilla and mandible.

 Placement of miniscrews in the buccal interradicular region is one of the most common approaches used for distal tooth movement. Although the interradicular miniscrews may reduce complications related to soft tissue irritation, the limited interradicular space can obstruct tooth movement. Therefore, now-a-days, the IZCs (infrazygomatic crest screws) are more well used as they don’t interfere the path of  tooth movement due to their extra alveolar placement. These extra alveolar TADs  have anatomic advantages of the infrazygomatic crest region i.e. thick cortical bone  which contribute to better primary stability of miniscrews and provide the possibility for unobstructed tooth movement.

IZC is a bony crest in the maxilla extending from the buccal plate of the alveolar process. It runs lateral to the roots of the first and second maxillary molars and extends 2cms or more to the zygomaticomaxillary suture, superiorly. Clinically it is a palpable ridge running along the curvature between the alveolar and zygomatic process of the maxilla. However, the location of this crest of the cortical bone is said to vary among young and old subjects. In young subjects, it is said to be located between the maxillary second premolar and first molar and in adults, it is above the maxillary first molar.

The anatomic limits, biomechanical perspectives, and the side effects are of prime considerations to master this technique but because a lot of controversies exist in the literature specifically regarding the placement, clinical efficiency and failure rates of mini-implants placed in the IZC region.

The factors associated with the failure rate of IZCs are still unclear. Hardly any CBCT studies have been done to assess the rate and reasons for failure of IZCs.  Hence, the objective of this study is to do the evidence based clinical trial for evaluating the efficacy and efficiency as well as the factors responsible for failure of IZCs as orthodontic implants. Aim is to evaluate the bone quality, insertion angle, and proximity to maxillary sinus on the survival rates of infrazygomatic crest miniscrews by 3-dimensional(3D) CBCT images.