Evaluation of the Long-Term Success and Patient-Related Outcomes of Zygomatic Implants in Atrophic Maxillary Ridges

Introduction Zygomatic implants (ZIs) have emerged as a promising option for rehabilitating completely edentulous patients with severe maxillary atrophy. These implants anchor into the zygomatic bone, bypassing the need for extensive grafting procedures. Success rates in dental and craniofacial implant surgeries can be influenced by several surgical factors, including suture techniques, flap design, and treatment planning. The research aimed to present the clinical outcomes and complications in individuals with severely resorbed maxillae who underwent prosthodontic rehabilitation using the Quad Zygoma Protocol (QZP) and the Anatomy-Guided Approach (AGA), focusing on long-term assessment. Material and methods Data for this retrospective study were extracted from the institution's patient database, involving a meticulous review of patient records. This comprehensive examination encompassed demographic data, preoperative assessments, details of surgical procedures, postoperative complications, and subsequent follow-up evaluations. Patients with severe maxillary bone deficiencies resulting in complete edentulism, due to inadequate bone quality and quantity in both anterior and posterior regions, were selected for inclusion. Exclusion criteria were applied to individuals with incomplete records or insufficient follow-up data, as well as those who underwent alternative treatment modalities or presented with comorbidities potentially impacting implant outcomes. The selected patients underwent treatment utilizing the QZP, with each participant subjected to a minimum three-year follow-up period. The implant survival rate, prosthetic success, complications, and Oral Health-Related Quality of Life using the OHIP-14 questionnaire were assessed. Results At the end of the follow-up period involving 12 patients (eight men, four women) with 43 ZIs - 37 from Neodent, four from Nobel Biocare, and two from Norris - with a mean duration of 4.3 years (range: 1.2-5.4), the overall success rate stood at 99.08%, with only 1 out of 42 implants failing. All patients received immediate loading with an acrylic prosthesis, proving effective in 98.2% of cases. The most common issues observed were localized soft tissue inflammation (35.7%) and sinus inflammation (12.5%), occurring after mean follow-up periods of 1.2 and 3.5 years, respectively. In 12 patients, the mean score of the OHIP-14 questionnaire was 1.6 ± 2.6, with a follow-up period of 5 ± 0.6 years. Conclusion The QZP has consistently demonstrated excellent long-term success in restoring severely reduced maxillary structures. An immediate loading approach could aid in stabilizing ZIs through cross-arch support.

Finite Element Analysis (FEA) of a Premaxillary Device: A New Type of Subperiosteal Implant to Treat Severe Atrophy of the Maxilla

Extreme atrophy of the maxilla still poses challenges for clinicians. Some of the techniques used to address this issue can be complex, risky, expensive, and time consuming, often requiring skilled surgeons. While many commonly used techniques have achieved very high success rates, complications may arise in certain cases. In this context, the premaxillary device (PD) technique offers a simpler approach to reconstruct severely atrophic maxillae, aiming to avoid more complicated and risky surgical procedures. Finite element analysis (FEA) enables the evaluation of different aspects of dental implant biomechanics. Our results demonstrated that using a PD allows for an optimal distribution of stresses on the basal bone, avoiding tension peaks that can lead to bone resorption or implant failure. ANSYS® was used to perform localized finite element analysis (FEA), enabling a more precise examination of the peri-crestal area and the PD through an accurate mesh element reconstruction, which facilitated the mathematical solution of FEA. The most favorable biomechanical behavior was observed for materials such as titanium alloys, which helped to reduce stress levels on bone, implants, screws, and abutments. Additionally, stress values remained within the limits of basal bone and titanium alloy strengths. In conclusion, from a biomechanical point of view, PDs appear to be viable alternatives for rehabilitating severe atrophic maxillae.