ITI consensus report on zygomatic implants: indications, evaluation of surgical techniques and long-term treatment outcomes.

OBJECTIVES: The aim of the ITI Consensus Workshop on zygomatic implants was to provide Consensus Statements and Clinical Recommendations for the use of zygomatic implants. MATERIALS AND METHODS: Three systematic reviews and one narrative review were written to address focused questions on (1) the indications for the use of zygomatic implants; (2) the survival rates and complications associated with surgery in zygomatic implant placement; (3) long-term survival rates of zygomatic implants and (4) the biomechanical principles involved when zygoma implants are placed under functional loads. Based on the reviews, three working groups then developed Consensus Statements and Clinical Recommendations. These were discussed in a plenary and finalized in Delphi rounds. RESULTS: A total of 21 Consensus Statements were developed from the systematic reviews. Additionally, the group developed 17 Clinical Recommendations based on the Consensus Statements and the combined expertise of the participants. CONCLUSIONS: Zygomatic implants are mainly indicated in cases with maxillary bone atrophy or deficiency. Long-term mean zygomatic implant survival was 96.2% [95% CI 93.8; 97.7] over a mean follow-up of 75.4 months (6.3 years) with a follow-up range of 36-141.6 months (3-11.8 years). Immediate loading showed a statistically significant increase in survival over delayed loading. Sinusitis presented with a total prevalence of 14.2% [95% CI 8.8; 22.0] over a mean 65.4 months follow-up, representing the most common complication which may lead to zygomatic implant loss. The international experts suggested clinical recommendations regarding planning, surgery, restoration, outcomes, and the patient's perspective.

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

PURPOSE: The present systematic review aimed to investigate the accuracy of zygomatic implant (ZI) placement using dynamic computer-aided surgery (d-CAIS), static computer-aided surgery (s-CAIS), and a free-hand approach in patients with severe atrophic edentulous maxilla and/or deficient maxilla. METHODS: Electronic and manual literature searches until May 2023 were performed in the PubMed/Medline, Scopus, Cochrane Library, and Web of Science databases. Clinical trials and cadaver studies were selected. The primary outcome was planned/placed deviation. Secondary outcomes were to evaluate the survival of ZI and surgical complications. Random-effects meta-analyses were conducted and meta-regression was utilized to compare fiducial registration amounts for d-CAIS and the different designs of s-CAIS. RESULTS: A total of 14 studies with 511 ZIs were included (Nobel Biocare: 274, Southern Implant: 42, SIN Implant: 16, non-mentioned: 179). The pooled mean ZI deviations from the d-CAIS group were 1.81 mm (95% CI: 1.34-2.29) at the entry point and 2.95 mm (95% CI: 1.66-4.24) at the apex point, and angular deviations were 3.49 degrees (95% CI: 2.04-4.93). The pooled mean ZI deviations from the s-CAIS group were 1.19 mm (95% CI: 0.83-1.54) at the entry point and 1.80 mm (95% CI: 1.10-2.50) at the apex point, and angular deviations were 2.15 degrees (95% CI: 1.43-2.88). The pooled mean ZI deviations from the free-hand group were 2.04 mm (95% CI: 1.69-2.39) at the entry point and 3.23 mm (95% CI: 2.34-4.12) at the apex point, and angular deviations were 4.92 degrees (95% CI: 3.86-5.98). There was strong evidence of differences in the average entry, apex, and angular deviation between the navigation, surgical guide, and free-hand groups (p < 0.01). A significant inverse correlation was observed between the number of fiducial screws and the planned/placed deviation regarding entry, apex, and angular measurements. CONCLUSION: Using d-CAIS and modified s-CAIS for ZI surgery has shown clinically acceptable outcomes regarding average entry, apex, and angular deviations. The maximal deviation values were predominantly observed in the conventional s-CAIS. Surgeons should be mindful of potential deviations and complications regardless of the decision making in different guide approaches.

Evaluation of surgical techniques in survival rate and complications of zygomatic implants for the rehabilitation of the atrophic edentulous maxilla: a systematic review.

PURPOSE: To assess the outcome [zygomatic implant (ZI) survival] and complications of the original surgical technique (OST) and an Anatomy-Guided approach (AGA) in the placement of ZI in patients with severely atrophic maxillae. METHODS: Two independent reviewers conducted an electronic literature search from January 2000 to August 2022. The inclusion criteria were articles reporting at least five patients with severely atrophic edentulous maxilla undergoing placement OST and/or AGA, with a minimum of 6 months of follow-up. Number of patients, defect characteristics, number of ZI, implant details, surgical technique, survival rate, loading protocol, prosthetic rehabilitation, complications, and follow-up period were compared. RESULTS: Twenty-four studies comprised 2194 ZI in 918 patients with 41 failures. The ZI survival rate was 90.3-100% in OST and 90.4-100% in AGA. Probability of complications with ZI with OST was as follows: sinusitis, 9.53%; soft tissue infection, 7.50%; paresthesia, 10.78%; oroantral fistulas, 4.58%; and direct surgical complication, 6.91%. With AGA, the presenting complications were as follows: sinusitis, 4.39%; soft tissue infection, 4.35%; paresthesia, 0.55%; oroantral fistulas, 1.71%; and direct surgical complication, 1.60%. The prevalence of immediate loading protocol was 22.3% in OST and 89.6% in the AGA. Due to the heterogeneity of studies, statistical comparison was only possible after the descriptive analysis. CONCLUSIONS: Based on the current systematic review, placing ZI in severely atrophic edentulous maxillae rehabilitation with the OST and AGA is associated with a high implant survival rate and surgical complications within a minimum of 6 months follow-up. Complications, including sinusitis and soft tissue infection around the implant, are the most common. The utilization of immediate loading protocol is more observed in AGA than in OST.

Round and flat zygomatic implants: effectiveness after a 1-year follow-up non-interventional study.

INTRODUCTION: There are few zygomatic implants (ZI) designs available. The objective of this non-interventional study was to report the effectiveness of two new site-specific ZI, selected and placed following the zygoma anatomy-guided approach (ZAGA). MATERIALS AND METHODS: Consecutive patients presenting indications for rehabilitation using ZI were treated according to ZAGA Concept recommendations. Implants were immediately loaded following the manufacturer's instructions. Success criteria regarding prosthetic offset, rhino-sinus status, soft tissue condition, and implant stability were additionally used as outcome parameters. RESULTS: Twenty patients were followed for a period of 12 to 28 months (average 18.8 months). Ten received 2 ZI plus regular anterior implants; One received 3 ZI plus regular implants and nine received 4 ZI. In total, 59 ZI were placed, 34 (58%) Straumann ZAGA-Flat design, and 25 (42%) ZAGA-Round. Forty-nine percent of the sites were classified as ZAGA-4 type and 27% as ZAGA-2. Four patients (20%) presented discontinuities of the sinus-nose floor before surgery and 15 patients (75%) presented previous sinus opacities. All implants bar one reached more than 45 N.cm of insertion torque. No surgical complications were observed. After 1 year, the modified Lund-Mackay score was negative in 17 patients. Seventeen sites in 11 patients exhibited decreased opacity when pre-surgical imaging was compared to 1-year post-surgical CBCT. All implants and prostheses remained stable and in function. CONCLUSIONS: The study concluded 100% implant/prosthesis survival rates and low complication levels. Within the limitations of the sample and observation period, results suggest that even in cases of extremely resorbed maxillae (as per cases in this study), ZAGA-Flat and ZAGA-Round ZI are viable treatment options when restoring atrophic maxillae following the ZAGA protocol.

Quad Zygoma: Technique and Realities.

Four zygomatic implants may be used in patients with severe maxillary atrophy for rehabilitation with a fixed or removable prosthesis. Immediate loading is also typically performed, providing patients with a less invasive and more efficient solution for rehabilitation. Options for immediate loading are presented. The indications, contraindications, procedure, and complications are reviewed. Appropriate treatment planning and work-up are highlighted, as they are required for success in conjunction with advanced surgical skill. Scientific evidence, although lacking in quantity, suggests that the quad zygoma approach offers a predictable solution for the challenge of severe maxillary atrophy; high implant survival rates are noted.

Sinus reactions to immediately loaded zygoma implants: a clinical and radiological study.

AIM: There are no published studies regarding sinus reactions to immediately loaded zygomatic implants. The aim of this study was to evaluate the maxillary sinus in a cohort of patients by means of clinical criteria and computerised tomography performed before surgery and after zygomatic implant placement (immediate function protocol). MATERIALS AND METHODS: A total of 36 patients with 71 immediately loaded zygomatic implants were evaluated to find clinical criteria of maxillary sinus disturbance 13 to 42 months (average 21.9 months) after zygoma implant placement. A total of 44 implants had a machined surface and 27 had a porous titanium oxide surface. Twenty-six patients with 52 immediately loaded zygomatic implants were evaluated by means of a CT scan of the paranasal sinuses, 3 to 20 months (average 10.5 months) after zygomatic implant placement. All patients had no sinus symptoms before surgery and had a preoperative CT scan. RESULTS: No clinical signs or symptoms of sinusitis were found. Radiological opacity of the antrum was found in two sinuses (out of 52), and minimal thickening of the Schneiderian membrane was found in 12 patients (out of 26). In eight of them, this was present in the preoperative CT scan. CONCLUSIONS: Sinuses penetrated by zygomatic implants seem to maintain a normal physiology. However, in approximately 15 to 20% of patients, early radiological findings without clinical symptoms were observed.

Clinical outcome of 42 patients treated with 81 immediately loaded zygomatic implants: a 12- to 42-month retrospective study.

AIM: Rehabilitation of the edentulous atrophic maxilla by implants to allow placement of a fixed dental prosthesis remains a challenge, especially if immediate function is provided. The aim of this retrospective study was to evaluate the success rate of immediately loaded zygomatic implants placed in atrophic maxillae. MATERIALS AND METHODS: Forty-two consecutively treated patients (19 men and 23 women), with a mean age of 57 years (range: 34 to 79 years) were followed for at least one year (range: 12 to 42 months, mean: 20.5 months). Thirty-seven patients were totally edentulous and five were partially edentulous. In total, 81 zygomatic and 140 conventional implants were inserted. The success criteria for the zygomatic implants were: (1) confirmed individual implant anchorage to the zygomatic bone by means of anteroposterior cranial radiograph; (2) the implant acting as an anchor for the functional prostheses; (3) no suppuration, pain, or ongoing pathological process at maxillary and zygomatic level; (4) confirmed individual implant stability. All patients had a fixed prosthesis screwed onto implants within 48 hours of implant placement. Descriptive statistics were used to analyse the data. RESULTS: After one year, there was no patient drop-out. None of the zygomatic implants were lost over the observation period (100% success rate). Four conventional implants were lost, resulting in a success rate of 97%. All the prostheses were stable. Oroantral fistula and sinusitis was found in one patient, which was solved with antibiotics and meatotomy, with no further complications. Soft tissue swelling and pain at the zygomatic area were found in another patient after 10 days of surgery. This was solved with antibiotics, with no further complications. CONCLUSIONS: Zygomatic implants together with conventional implants in severely resorbed maxillae appear to be a reliable technique for providing immediate function to patients. The time of treatment can be substantially decreased in a predictable way if zygomatic implants are loaded immediately after placement.