Posteroanterior cephalometric immediate assessment of infrazygomatic crest mini-implants: A retrospective study

Aim: There are wide variations in placement of extra-alveolar bone screws that can occur in angulation, the height of placement, and other operator-related factors. The aim of this study is to comparatively evaluate the position of bilaterally placed infrazygomatic crest (IZC) mini-implants factors such as height, angulation, the length outside the bone, if any sinus penetration and the depth of penetration into the sinus. Materials and Methods: The study is a retrospective pilot study collected from the hospital records over the time period study was conducted. Posteroanterior cephalograms taken for patients after bilateral placement of IZC were collected. The comparison of the variations in placement for the right and left side was done. Results: There is wide variation among the sample and comparison to the right and left sides in the same sample. The height of placement above the buccal tube ranged from 7 to 8 mm. There were wide variations in angulation of the implant to the buccal bone ranging from 15° to up to 50°. Of the total size of the IZC mini-implant 6-7 mm of the implant was left outside the bone and an average of 2.5 mm of sinus penetration was commonly observed. Conclusion: Postplacement assessment of IZC can be done with a posteroanterior cephalogram. The implant was placed at a height of 6-10 mm above the buccal tube; there were wide variations in angulations between right and left side; 4-7 mm of the mini-implant did not engage the IZC, and there was a high incidence of sinus penetration ranging from 1 mm to 3.5 mm.