Accuracy of Zygomatic Implant Placement Using a Full Digital Planning and Custom-Made Bone-Supported Guide: A Retrospective Observational Cohort Study

Abstract

The aim of the study was to evaluate the accuracy of zygomatic implant placement using customized bone-supported laser-sintered titanium templates. Pre-surgical computed tomography (CT) scans allowed to develop the ideal virtual planning for each patient. Direct metal laser-sintering was used to create the surgical guides for the implant placement. Post-operative CT scans were taken 6 months after surgery to assess any differences between the planned and placed zygomatic implants. Qualitative and quantitative three-dimensional analyses were performed with the software Slicer3D, recording linear and angular displacements after the surface registration of the planned and placed models of each implant. A total of 59 zygomatic implants were analyzed. Apical displacement showed a mean movement of 0.57 ± 0.49 mm on the X-axis, 1.1 ± 0.6 mm on the Y-axis, and 1.15 ± 0.69 mm on the Z-axis for the anterior implant, with a linear displacement of 0.51 ± 0.51 mm on the X-axis, 1.48 ± 0.9 mm on the Y-axis, and 1.34 ± 0.9 mm on the Z-axis for the posterior implant. The basal displacement showed a mean movement of 0.33 ± 0.25 mm on the X-axis, 0.66 ± 0.47 mm on the Y-axis, and 0.58 ± 0.4 mm on the Z-axis for the anterior implant, with a linear displacement of 0.39 ± 0.43 mm on the X-axis, 0.42 ± 0.35 mm on the Y-axis, and 0.66 ± 0.4 mm on the Z-axis for the posterior implant. The angular displacements recorded significative differences between the anterior implants (yaw: 0.56 ± 0.46°; pitch: 0.52 ± 0.45°; roll: 0.57 ± 0.44°) and posterior implants (yaw: 1.3 ± 0.8°; pitch: 1.3 ± 0.78°; roll: 1.28 ± 1.1°) (p < 0.05). Fully guided surgery showed good accuracy for zygomatic implant placement and it should be considered in the decision-making process.

The Accuracy of Zygomatic Implant Placement Assisted by Dynamic Computer-Aided Surgery: A Systematic Review and Meta-Analysis

“…After removing duplicates ( n = 56), 51 articles were screened using title-abstract-keyword reading, leaving 35 reports eligible (substantial agreement, κ = 0.95). After full-text reading and a subsequent search for relevant citations, 14 studies were included in this systematic review [ 8 , 10 , 11 , 12 , 13 , 14 , 15 , 19 , 32 , 33 , 34 , 35 , 36 , 37 ] (100% of agreement among the reviewers) ( Figure 1 ). One current retrospective study from Wu included [ 19 ], and other fives studies from the same team (Shanghai Jiaotong University) were excluded due to the same population were collected in Wu’s publication [ 19 ].…”

“…The main characteristics of the included studies are described in Table 1 according to guidance approach, system, number of examinations, ZI characteristics, and conclusions. A total of 14 studies [ 8 , 10 , 11 , 12 , 13 , 14 , 15 , 19 , 32 , 33 , 34 , 35 , 36 , 37 ], including one RCT [ 32 ], two retrospective studies [ 15 , 19 ], five prospective studies [ 12 , 13 , 33 , 34 , 37 ], six cadaver studies with one comparative analysis [ 8 , 10 , 11 , 14 , 35 , 36 ], were retrieved from the search. Those reported ZI planned/placed accuracy in 144 patients (77 male and 67 female) and 35 cadavers with total of 511 ZIs (Nobel Biocare: 274, Southern Implant: 42, SIN Implant: 16, non-mentioned: 179); six studies used 35 cadavers with 118 ZIs.…”

“…In the navigation group [ 19 , 32 , 33 ], 57 patients were treated via the classic approach, 35 patients via the quad zygoma approach, and in ten patients ZIs were placed in cases of deficient maxilla. In the static guide group [ 8 , 10 , 11 , 12 , 13 , 14 , 15 , 34 , 35 , 36 ], nine patients and six cadavers were treated via the classic approach, 18 patients and 24 patients via the quad zygoma approach, and in 11 patients and five cadavers, ZIs were used for maxillary defect cases. In the freehand group [ 10 , 37 ], one patient was treated with the classic approach, and three patients and ten cadavers received a quad zygoma approach.…”

“…This guide was supported by the bone in three studies and supported by the mucosal tissue in one study. Six studies used a modified surgical guide with double or extra-long sleeves designs [ 10 , 11 , 12 , 13 , 14 , 15 ]. The modified surgical guides were larger than conventional ones and were fixed with multiple screws to the bone.…”

“…In 2016, a modified surgical guide with double sleeves, designed to stabilize the long drill and to overcome the deviation, was introduced [ 9 ]. Later, studies focused on utilizing this modified guide concept to assist in ZI placement with increased intra-operative safety and accuracy [ 10 , 11 , 12 , 13 , 14 , 15 ]. Gecchi et al demonstrated that the accuracy of ZI placement with a modified surgical guide was superior to the free-hand approach, particularly at the level of the zygomatic bone [ 10 ].…”