Evaluation of Accuracy of Three-Dimensionally Guided Zygomatic Implant Installation

Evaluation of the Accuracy of Three-Dimensionally Guided Zygomatic Implant Placement: A Prospective Clinical Study

This study was conducted at the Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Tanta University. A prospective non-controlled clinical study was performed on ten patients with compromised zygomaticomaxillary bone. Surgical intervention was carried out using a customized surgical guide.

Pre-surgical planning was performed using computed tomography (CT) scans for each patient. Surgical guides were fabricated using direct metal laser sintering technology. Zygomatic implants were inserted using a guided surgical protocol and specialized instruments.

Postoperative CT scans were obtained to evaluate deviations between the planned and actual implant positions. Accuracy was assessed by superimposing the postoperative implant position onto the virtual pre-surgical implant plan using dedicated software. Descriptive and bivariate statistical analyses were performed.

Study Overview

• Status: Completed
• Conditions: Maxillary Defect Reconstruction; Atrophic Edentulous Maxilla
• Intervention / Treatment: Procedure: zygomatic implant installation using custamized bone supported surgical guide

Detailed Description

Purpose: The aim of this study was to evaluate the accuracy of using a static surgical guide protocol for zygomatic implant placement in patients with compromised zygomaticomaxillary bone.

Materials and methods: All the patients had a pre-operative initial consultation interview with the surgeons mainly for collecting demographic data, taking general medical, surgical, and dental history, and listening to the patient's esthetic complaints and postoperative expectations.

• A pre-operative multiplanar CT scan of the face to evaluate residual maxillary bone, zygomatic bone, and sinus condition to detect any sinus pathology. This gives initial data about the orientation of the zygomatic implant (ZI), positioning, angulation, and length using 3D planning software.
• The resulting DICOM files were segmented, forming STL (Standard Triangulation Language) files that were used as a baseline for post-operative superimposition.
• Under general anesthesia, patients underwent either contralateral nasal intubation to the working side or oral intubation.
• A palatal paracrestal incision was carried out in the maxillary soft tissues with vertical posterior releasing incisions.
• The muco-periosteal flap was elevated to expose the alveolar crest, the piriform aperture, the lateral wall of the maxillary sinus if present, the infraorbital nerve emergence, the maxillary tuberosity, and the central and the posterior part of the zygomatic bone.
• The surgical guide was fitted in its position and fixed with cortical screws. Implant osteotomy was performed. Then zygomatic implants were inserted.
• The wound was irrigated with normal saline and debridement of the surgical field before suturing using Vicryl 3/0.

Post-operative assessment:

All patients were regularly followed up on the 7th & 14th days postoperatively to assess the following parameters:

• The oral health-related quality of life in edentulous adults was assessed using the OHIP-14 questionnaire.

Radiographic assessment:

1. A post-operative CT scan of each patient with implants was taken after the surgery, with follow-up CT after 6 months and one year
2. The DICOM images of the post-operative CT were uploaded in dedicated software.
3. Segmentation based on tissue density was carried out to separate implants from the surrounding bone.
4. The STL files of the maxillary bone with the planned implant positions obtained from the initial CT scan were uploaded into the software.

Superimposition

1. The postoperative CT scan was imported into Mimics software, where the DICOM file was segmented. It was then brought into 3-matic, and the Postoperative segmentation was aligned with the planned skull using a point registration algorithm. Final refinement of the registration was completed through global registration.
2. The amount of deviation was calculated by determining the same point at the center of the implant platform in both the post-operative segmentation and the plan. Then the amount of deviation was calculated by measuring the distance in millimeters between points and the vector of displacement. (coronal, apical, and angular deviations).

Radiographical evaluation:

Implant Placement Accuracy

1. The implant lengths By superimposition of the postoperative implant length onto the virtually planned implant length
2. The 3D implant angle deviation By measuring the deviation between the postoperative coronal entry point of the implant and the virtually planned coronal entry point
3. The accuracy of the abutment position in the occlusal plane. By superimposition of the postoperative position of the multiunit abutments, onto the virtually planned abutment positions

• Study Type: Interventional
• Enrollment (Actual): 10
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Elgharbia
    • Tanta, Elgharbia, Egypt, 3111
      • faculty of dentistry , Tanta university

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

- 1. Lack of maxillary posterior bone in which standard implants are impossible to insert.

2. Post-surgical maxillary defects with limitations of maxillary bone reconstruction due to lack of soft tissue coverage.

3. Failure of previous reconstructive procedures.

Exclusion Criteria:

1. Opportunity of alternative treatment modalities with bone grafting and standard implants.
2. Any relevant systemic or local diseases that might affect the bone healing, like uncontrolled diabetic patients or cancer patients who are still on chemotherapy or previously received radiation on the head and neck region.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Single-arm interventional study; Patients received zygomatic implants using a customized bone-supported surgical guide following three-dimensional preoperative planning.

Procedure: zygomatic implant installation using custamized bone supported surgical guide; Zygomatic implant placement using a customized bone-supported surgical guide. Indications included: Severe posterior maxillary bone deficiency preventing placement of conventional implants; Post-surgical maxillary defects with limited options for bone reconstruction due to inadequate soft tissue coverage; Failure of previous reconstructive procedures

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
implant success.	Implant success was assessed based on clinical stability and osseointegration. Stability was evaluated using torque testing during implant uncovering with a torque value of 10-20 Ncm applied to the multiunit abutment screw without implant rotation.	3 months
Implant survival	Implant survival was assessed based on the absence of implant mobility, pain, infection, peri-implant inflammation, suppuration, and progressive bone loss.	1 year
Coronal Deviation	Deviation at the coronal entry point of the implant between the planned implant position and the actual postoperative implant position measured using three-dimensional superimposition of preoperative planning and postoperative CT scans.	1 week
Apical Deviation	Linear deviation at the apical endpoint of the implant between the planned implant position and the postoperative implant position measured using three-dimensional image superimposition.	1 week
Angular Deviation	Angular deviation between the long axis of the planned implant and the postoperative implant measured in degrees using 3D software analysis.	1 week
Soft tissue wound healing:	Postoperative clinical evaluation of the surgical site including signs of inflammation, infection, or intraoral wound dehiscence.	4 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prosthetic Survival	Evaluation of prosthetic success including structural integrity of the prosthesis, absence of fracture or wear, and stability of the implant-prosthesis connection.	1 year
Oral Health Impact Profile (OHIP-14)	Patient-reported outcome measured using the Oral Health Impact Profile-14 questionnaire to assess functional limitation, pain, psychological discomfort, and social disability.	1 year

Collaborators and Investigators

• Sponsor: Tanta University
• Investigators: Principal Investigator: Eslam A Gharieb, Tanta University

Study record dates

Study Major Dates

• Study Start (Actual): June 20, 2023
• Primary Completion (Actual): November 15, 2024
• Study Completion (Actual): December 20, 2025

Study Registration Dates

• First Submitted: March 5, 2026
• First Submitted That Met QC Criteria: March 5, 2026
• First Posted (Actual): March 11, 2026

Study Record Updates

• Last Update Posted (Actual): March 11, 2026
• Last Update Submitted That Met QC Criteria: March 5, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: guided zygomatic implant surgery; Post-Mucormycosis Rehabilitation; Bone-Supported zygomatic implant guide
• Additional Relevant MeSH Terms: Bone Resorption; Bone Diseases; Musculoskeletal Diseases; Stomatognathic Diseases; Jaw Diseases; Maxillary Diseases; Atrophic Maxilla
• Other Study ID Numbers: OS-3-23-13

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data collected during the study will not be shared outside the study team.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No