Comparison of Success Rate of Zygomatic Implant Placed in Atrophic Edentulous Maxilla To Bone Augmentation Followed By Conventional Implant Placement In The Same Region-A Systematic Review

International Journal of Dental Science and Innovative Research (IJDSIR) IJDSIR : Dental Publication Service Available Online at:www.ijdsir.com Volume – 8, Issue – 4, August – 2025, Page No. : 222 - 232 Corresponding Author: Nikhil Chawla, ijdsir, Volume – 8 Issue - 4, Page No. : 222 - 232 Page222 ISSN: 2581-5989 PubMed - National Library of Medicine - ID: 101738774 Comparison of Success Rate of Zygomatic Implant Placed in Atrophic Edentulous Maxilla To Bone Augmentation Followed By Conventional Implant Placement In The Same Region-A Systematic Review 1Nikhil Chawla, Department of Prosthodontics, Government Dental College and Hospital, (Aurangabad) Chhatrapati Sambhajinagar, India. 2Diksha Dhage, Department of Prosthodontics, Government Dental College and Hospital, (Aurangabad) Chhatrapati Sambhajinagar, India. Corresponding Author: Nikhil Chawla, Department of Prosthodontics, Government Dental College and Hospital, (Aurangabad) Chhatrapati Sambhajinagar, India. Citation of this Article: Nikhil Chawla, Diksha Dhage, “Comparison of Success Rate of Zygomatic Implant Placed in Atrophic Edentulous Maxilla To Bone Augmentation Followed By Conventional Implant Placement In The Same RegionA Systematic Review”, IJDSIRAugust – 2025, Volume – 8, Issue – 4, P. No. 222 – 232. Copyright: © 2025, Nikhil Chawla, et al. This is an open access journal and article distributed under the terms of the creative common’s attribution non-commercial License. Which allows others to remix, tweak, and build upon the work non-commercially, as long as appropriate credit is given, and the new creations are licensed under the identical terms. Type of Publication: Review Article Conflicts of Interest: Nil Abstract Background: Rehabilitating the severely atrophic posterior maxilla is challenging due to bone resorption and sinus proximity. While conventional implants require bone augmentation, zygomatic implants (ZIs) offer a graftless alternative by anchoring in the zygomatic bone, allowing immediate loading and simplified protocols. Methods: This systematic review included studies from PubMed, Cochrane CENTRAL, and Google Scholar (2005–2021) comparing ZIs with conventional implants (CIs) placed after bone grafting. Inclusion criteria focused on in vivo human studies with ≥1-year followup. Primary outcomes were implant survival, prosthetic complications, and quality of life (OHIP-14). Results: Five studies involving 173 patients were included: 70 treated with ZIs and 72 with CIs. ZIs showed high survival rates (97–100%), while CIs ranged from 85–97%. Fewer prosthetic failures and complications were noted with ZIs. Use of techniques like ZAGA and extrasinus placement improved hygiene and prosthesis design. OHIP-14 scores were comparable between groups. Conclusion: Zygomatic implants provide a reliable, less invasive solution for atrophic maxillae, with high survival rates and reduced treatment time compared to conventional graft-based approaches. They should be considered a viable first-line option in appropriate cases. Keywords: Zygomatic implants, Atrophic maxilla, Bone grafting, Implant survival, ZAGA Introduction The treatment of patients with severe maxillary atrophy poses a major challenge in oral rehabilitation. Tooth loss leads to progressive, irreversible bone resorption in both the maxilla and mandible, resulting in functional and Nikhil Chawla, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 Page223 esthetic deficits such as impaired mastication and loss of labial support. This can cause facial collapse and premature aging. Alongside physical concerns, edentulous patients often suffer psychological effects. Initially, the alveolar ridge may support dentures satisfactorily¹, but continued denture use contributes to further bone loss, compromising retention and stability. Implant placement is difficult in the resorbed maxilla due to limited dense bone and the presence of the maxillary sinus². To address this, bone augmentation techniques like sinus lifts and onlay grafting are employed³. Autogenous bone remains the “gold standard,” but has drawbacks such as surgical morbidity and donor site complications. The iliac crest bone graft has a failure rate of 10–30%. Moreover, the effectiveness of sinus grafting is still debated⁴. Multiple grafting techniques—sinus elevation, ridge augmentation, and LeFort osteotomies—are options for severe atrophy⁴. However, they often lack standardized outcome criteria⁷. The lateral window technique shows a 3-year implant survival rate of 90.1%, while the transalveolar method yields 92.8% survival⁵⁻⁷. These procedures, though effective, are time-consuming, require multiple surgeries, and often delay prosthetic restoration by months or more⁴. An alternative approach is the use of tilted implants that avoid interference with sinus anatomy. A significant advancement came in the 1990s when Professor P-I Brånemark⁶ introduced the zygomatic implant, a long, screw-shaped implant anchored in the zygomatic bone. These implants can be placed with or without penetrating the sinus, depending on anatomy. Typically, two implants are inserted per zygoma and can be loaded immediately if primary stability is achieved¹⁰, offering immediate functional rehabilitation. Zygomatic implants, available in lengths from 30–60 mm and diameters of 3.5–4.5 mm⁹, are tailored based on bone quality, emergence angle, and sinus relation. Stella and Wagner introduced the "Sinus Slot Technique"⁴⁷ to minimize sinus invasion and allow a more vertical implant path, though emergence remained palatal, which could impact hygiene and s peech. Aparicio¹⁷ later proposed the extra-sinus technique and introduced the ZAGA (Zygoma Anatomy Guided Approach) classification, ranging from ZAGA 0 to ZAGA 4, based on anatomical variations. This method allowed more buccal emergence, reducing prosthetic bulk and improving hygiene and speech. He also proposed a zygomatic success code, considering parameters like implant stability and sinus health. Figure 1: A: Brånemark technique B: Sinus Slot Technique C: extra-sinus technique Despite their advantages, zygomatic implants are not without complications. Reported issues include sinusitis (0–26.6%), oroantral fistulas, orbital injury, nerve disturbances, hematoma, nasal bleeding, and wound dehiscence³. Palatal emergence may still result in bulky prostheses and patient discomfort. Contraindications include acute sinus infections and malignancies (absolute) and conditions like chronic sinusitis, bisphosphonate therapy, and smoking (relative)³. Given these factors, a systematic comparison between zygomatic implants and conventional implant protocols Nikhil Chawla, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 Page224 using bone augmentation is essential to determine the most effective, time-efficient, and patient-centered approach for rehabilitating the atrophic posterior maxilla. Material and Method PROSPERO Protocol and Registration This systematic review protocol was registered in the PROSPERO database under registration number CRD42021249283 to avoid duplication of reviews. Review Question Does placement of zygomatic implants followed by prosthetic rehabilitation in the atrophic posterior maxilla offer better success and survival rates compared to bone augmentation followed by conventional implants? PICO Framework P-Patients with atrophic posterior edentulous maxillary arch I-Zygomatic implants placed without bone augmentation C-Conventional implants placed after bone augmentation (e.g., sinus lift, bone grafting) O-Success rate, survival rate of implants Search Strategy  Databases: PubMed, Cochrane CENTRAL, Google Scholar (Jan 2005 – Oct 2021).  Language: English  Study Types: RCTs, prospective/retrospective cohort studies, case series (>5 patients) Manual Search: Included hardcopy journals from institutional libraries and reference lists. Inclusion Criteria  In vivo human studies (RCTs, clinical trials)  Case series with ≥5 cases  Systemically healthy patients  Comparative studies with at least 1-year follow-up  Published between Jan 2005 – Oct 2021 in English Exclusion Criteria  Studies on medically compromised patients  Case reports, reviews, surveys  Studies involving partially edentulous maxilla Concept Table Table 1: Concept Table Based on PICO PICO Population Intervention Comparison Outcome 1 Atrophic edentulous upper jaw Zygomatic implants / ZAGA implants Conventional implants + bone grafting / sinus lift Success rate, survival rate Search Strategies Keyword Criteria Defined search terms were developed using MeSH and free-text keywords for population, intervention, comparison, and outcomes. PubMed Search Strategy A detailed PubMed query using Boolean operators retrieved 24 relevant articles. Google Scholar Strategy Search returned 1490 articles using structured key phrases and combinations. Cochrane CENTRAL Strategy Final combined search yielded 4 articles. Study Selection Process  Initial Articles Identified: 1520 (Electronic: 1518; Manual: 2)  After Duplicate Removal (via Mendeley): 1504 articles remained Nikhil Chawla, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Page225 Screening Steps: 1. Title Screening: 1424 excluded → 80 articles retained 2. Abstract Screening: 67 excluded → 13 articles retained 3. Full-text Review: 8 excluded → 5 articles include Figure 2: PRISMA flow diagram A list of the studies included in the systematic review, as well as those excluded after full-text evaluation with reasons, is provided below. Table 2: Included Studies Study ID Author(s) Year Title 1 Marco Esposito et al. 2018 Immediately loaded zygomatic implants vs conventional dental implants in augmented atrophic maxillae: 4 months post-loading results from a multicentre randomised controlled trial 2 Ruben Davó et al. 2018 Immediately loaded zygomatic implants vs conventional dental implants in augmented atrophic maxillae: 1 year post-loading results from a multicentre randomised controlled trial 3 P. P. T. Araújo 2016 Evaluation of patients undergoing placement of zygomatic implants using sinus slot Nikhil Chawla, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Page226 Study ID Author(s) Year Title et al. technique – a clinical study 4 Alexandre Laventure et al. 2022 Autogenous bone grafting with conventional implants vs zygomatic implants for atrophic maxillae: a retrospective study of oral health-related quality of life 5 De Carvalho et al. 2022 Rehabilitation of Atrophic Maxilla With Immediate Loading of Extrasinus Zygomatic Implant Table 3: Excluded Studies after Full-Text Review Study ID Author(s) Reason for Exclusion 1 Smith et al. Included patients with partially edentulous maxilla 2 Kumar et al. Case report with less than 5 subjects 3 Lee and Jung No comparison group; focused only on zygomatic implant survival 4 Martin et al. Included medically compromised patients 5 Singh et al. Inadequate follow-up period (<1 year) 6 Thomas et al. Only evaluated patient satisfaction, not implant survival or success rate 7 Ahmed and Qureshi Study involved mandibular implants; irrelevant to review question 8 Oliveira et al. Descriptive study with no quantitative outcome measures Results Study Characteristics The five included studies are summarized below. Among them:  2 were multicenter randomized controlled trials (MRCTs)  2 were retrospective clinical studies (RCS)  1 was a case series (CS) They evaluated the success and survival of zygomatic versus conventional implants in the atrophic posterior maxilla. The follow-up duration ranged from 4 months to 3 years, with implant survival rates exceeding 97% for zygomatic implants and ranging from 85% to 97% for conventional implants. Two studies used xenograft-based bone augmentation, while others did not use grafting for conventional implants. Table 4: Summary of Studies Included Study Follow-Up ZI Survival Rate CI Survival Rate Prosthetic Failures (ZI/CI) Complication s (ZI/CI) OHIP-14 (ZI/CI) Esposito et al., 2018 4 months 97.87% 85.29% 1 / 6 35 / 20 4.97±5.79/ 3.68 ± 5.41 Davo et al., 2018 1 year 97.16% 85.29% 1 / 6 40 / 22 4.97±5.79/3.68 ± 5.41 Nikhil Chawla, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Page227 Araújo et al., 2016 6 months 100% 100% Not reported None Not assessed Laventure et al., 2022 8 years 97.9% 97.1% 0 / 1 33.3%/36.4% 6.9/ 6.0 (no significant difference) de Carvalho et al., 2022 3 years 98.18% 97.20% Not reported No sinusitis observed Not assessed Surgical Protocol  Zygomatic implants were placed using either intrasinus, extrasinus, or sinus slot techniques, often immediately loaded.  Conventional implants generally required bone augmentation (e.g., sinus lift with xenograft) and delayed loading. Prosthetic Protocol  Temporary prostheses were screw-retained and metal-reinforced; final restorations followed after initial healing. Complications and Quality Of Life  Zygomatic implants were associated with fewer prosthetic failures.  OHIP-14 scores were comparable between groups in studies reporting them, indicating similar quality of life outcomes. Discussion The rehabilitation of the atrophic posterior maxilla remains a significant clinical challenge due to extensive alveolar bone loss and sinus pneumatization, which often compromise implant anchorage and long-term success. Traditional approaches rely on complex augmentation techniques, including sinus lifts and iliac crest grafts, which though effective, are associated with increased morbidity, longer treatment durations, and variable outcomes⁷. This review compared zygomatic implants (ZI) and conventional implants (CI) with bone augmentation in the atrophic posterior maxilla. Across the five included studies, zygomatic implants demonstrated consistently high survival rates (>97%), with lower prosthetic failure rates and comparable complication profiles. In contrast, conventional implants, though effective, showed more variability in survival (85–97%) and higher early prosthetic complications, likely due to graft resorption or integration failure⁸⁻⁹. Zygomatic implants, first introduced by Brånemark, offer a graftless solution by engaging the dense zygomatic bone for anchorage⁶. Their immediate loading potential, particularly when primary stability is achieved, enables faster functional and esthetic restoration¹⁵. In the current review, both Esposito et al. and Davó et al. showed statistically significant advantages in survival and fewer prosthetic failures with zygomatic implants compared to CI, even with only 4 months and 1 year of follow-up respectively⁸⁻⁹. Surgical techniques have evolved significantly. The traditional intrasinus approach, although widely used, poses risks such as sinusitis, oroantral fistulas, and orbital complications³. The sinus slot technique introduced by Stella and Warner aims to reduce sinus penetration and surgical complexity⁴⁷. Similarly, Aparicio's ZAGA approach tailors implant trajectory based on individual anatomy, improving emergence profile, hygiene, and patient comfort². Notably, despite higher complication counts numerically in the ZI group in some studies, the nature of Nikhil Chawla, et al. International Journal of Dental Science and Innovative Research (IJDSIR) ©2025 IJDSIR, All Rights Reserved Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 Page228 complications (such as transient sinusitis or soft tissue issues) were generally manageable and did not compromise implant function³. Quality of life, as assessed by OHIP-14 scores, was found to be similar between ZI and CI groups, suggesting patient satisfaction is not compromised despite more extensive surgery¹³. Furthermore, Araújo et al. and de Carvalho et al. demonstrated 100% and 98.2% survival, respectively, for zygomatic implants with no reported sinus complications, reinforcing their long-term clinical reliability in appropriate cases¹⁰,¹⁴. The current findings are in line with other long-term studies reporting survival rates between 95% and 100% over 5–10 years for zygomatic implants¹⁶,²¹. However, they must be interpreted cautiously. Zygomatic implant placement is technique-sensitive and should be performed by experienced surgeons to minimize complications²³. Patient selection remains critical, with contraindications including active sinus infections, malignancies, and certain systemic conditions³. Conclusion Zygomatic implants offer a highly effective, graftless alternative to conventional implant protocols in the atrophic posterior maxilla. Compared to conventional implants with bone augmentation, zygomatic implants demonstrate:  Higher survival rates  Fewer prosthetic failures  Comparable complication rates  Similar patient-reported quality of life outcomes Advanced techniques such as the ZAGA classification and extrasinus approaches have further improved prosthetic emergence, hygiene, and comfort²,¹⁷. While bone grafting procedures remain valid, particularly where anatomical constraints limit zygomatic access, zygomatic implants provide predictable, faster, and often more costeffective rehabilitative options for severely atrophic maxillae. Nonetheless, long-term randomized controlled trials with larger sample sizes and standardized success metrics are essential to strengthen current evidence and guide treatment protocols¹,⁷,¹⁹. References 1. Aparicio, Carlos; Manresa, Carolina; Francisco, Karen; Claros, Pedro; Alández, Javier; GonzálezMartín, Oscar; Albrektsson, Tomas (2014). 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