Abstract
Background: Zygomatic implants provide a predictable treatment option for rehabilitation of the severely atrophic maxilla while minimizing the need for extensive grafting. However, determining an optimal implant trajectory that maximizes bone–implant contact (BIC) remains a clinical challenge.
Aim: This study aimed to evaluate the ideal trajectory for zygomatic implant placement with maximum radiographic bone–implant contact (rBIC) using the proposed "5.5 rule."
Materials and Methods: This retrospective study analysed cone beam computed tomography (CBCT) scans of 10 completely edentulous patients classified as Cawood and Howell Class V or VI. Virtual zygomatic implants were planned according to the 5.5 rule: Point A — second premolar region (tangent to infraorbital foramen), Point B — centre of the zygoma, and Point C — outer cortical perforation. Digital planning was performed using Blue Sky Plan® software. Radiographic BIC was quantified on temporal and facial sides using built-in software measurement tools.
Results: The mean rBIC was 85.43% ± 6.43% on the temporal side and 88.8% ± 7.60% on the facial side, with an overall mean of 87%. The 5.5 rule consistently guided implant positioning through the central zygomatic bone, optimizing BIC.
Conclusions: The 5.5 rule offers a reliable, reproducible method for achieving optimal zygomatic implant trajectory with maximal bone–implant contact. Larger-scale clinical validation is recommended to confirm its predictive value.
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Authors & Affiliations
References
- Chrcanovic BR, Pedrosa AR, Custódio ALN. Zygomatic implants: A critical review of the surgical techniques. Oral Maxillofac Surg. 2013;17(1):1–9.
- Brånemark PI, Gröndahl K, Ohrnell LO, Nilsson P, Petruson B, Svensson B, et al. Zygoma fixture in the management of advanced atrophy of the maxilla: Technique and long-term results. Scand J Plast Reconstr Surg Hand Surg. 2004;38(2):70–85.
- Al-Nawas B, Wagner W. Materials in dental implantology. In: Ducheyne P, editor. Comprehensive Biomaterials II. Oxford: Elsevier; 2017. p. 1–13.
- Becktor JP, Hallström H, Isaksson S, Sennerby L. The use of particulate bone grafts from the mandible for maxillary sinus floor augmentation before placement of surface-modified implants. J Oral Maxillofac Surg. 2008;66(4):780–6.
- Collins TA, Brown GK, Johnson N, Massey JA, Nunn BD. Team management of atrophic edentulous patients with autogenous inlay, veneer, and split grafts and endosseous implants: Case reports. Quintessence Int. 1995;26(2):79–93.
- Stokholm R, Spin-Neto R, Nyengaard JR, Isidor F. Comparison of radiographic and histological assessment of peri-implant bone around oral implants. Clin Oral Implants Res. 2016;27(7):782–6.
- Donath K, Breuner G. A method for the study of undecalcified bones and teeth with attached soft tissues: The säge-schliff (sawing and grinding) technique. J Oral Pathol. 1982;11(4):318–26.
- Ritter L, Elger MC, Rothamel D, Fienitz T, Zinser M, Schwarz F, et al. Accuracy of peri-implant bone evaluation using cone beam CT, digital intraoral radiographs and histology. Dentomaxillofac Radiol. 2014;43(6):20130088.
- Hung KF, Ai QY, Fan SC, Wang F, Huang W, Wu YQ. Measurement of the zygomatic region for the optimal placement of quad zygomatic implants. Clin Implant Dent Relat Res. 2017;19(6):1013–20.
- Balshi TJ, Wolfinger GJ, Shuscavage NJ, Balshi SF. Zygomatic bone-to-implant contact in 77 patients with partially or completely edentulous maxilla. J Oral Maxillofac Surg. 2012;70(9):2065–70.
- Wang F, Bornstein MM, Hung K, Huang W, Fan S, Wu Y, et al. Application of real-time surgical navigation for zygomatic implant insertion in patients with severely atrophic maxilla. J Oral Maxillofac Surg. 2018;76(1):80–7.