Measurement Of The Zygomatic Region For The Optimal Placement Of Quad Zygomatic Implants And Accuracy Of A Real-time Surgical Navigation System For The Placement Of Quad Zygomatic Implants In The Severe Atrophic Maxilla

Purpose:To identify the optimal zygomatic areas for placing quad-zygomatic implants,and to evaluate the accuracy of a real-time surgical navigation system when used for quad zygomatic implant placementMaterials and Methods:The zygomatic length and thickness at designated lines and points were measured on the three-dimensional reconstruction.The differences of zygomatic thickness and length between patients with maxillary dentate and edentulous jaws,genders and ages were analysed.In edentulous maxillae,BICs of virtually placed implants at each point were measured,and part of them were placed quad zygomatic implants using a surgical navigation.The planned-placed distance deviations at entry points,exit points,and angle deviation of axes were measured on fused operation images.The differences of all the deviations between different groups,classified based on the lengths and locations of implants,were analysed.A p-value of<0.05 indicated statistical significanceResults:The largest thickness in the superior,middle and inferior regions were at Point A1(8.01±2.10 mm),Point B1(7.02± 1.73 mm)and Point C0(6.65±1.66 mm)respectively.The zygomatic length gradually increased from the anterior to the posterior(25.67±3.12 mm to 32.54±3.16 mm).The differences of zygomatic thickness and length were only significant between genders.The BICs of virtually placed implants at Point A3(16.70±4.18 mm),Point B2(13.88±3.50 mm)and Point C1(13.44±3.40 mm)were significantly higher than those at other points in each region.The entry,exit and angle deviation of the real-time surgical navigation system used for the placement of quad zygomatic implants were 1.24±0.78 mm,1.84±0.90 mm,and 2.12±0.99 degrees.The differences of all deviations were not significant,irrespective of the lengths or locations of the placed implants.Conclusion:The posterosuperior area of the zygoma was optimal for the apex of the anterior implant,and the centre of the middle and inferior areas of zygoma were optimal for the apex of the posterior implant.A real-time surgical navigation system used for the placement of quad zygomatic implants demonstrated a high level of accuracy,irrespective of the lengths or locations of the implants.