Comparative Evaluation of All-on-Four Rehabilitation Using Zygomatic and Conventional Implants in Patients With Atrophied Maxilla

Background: Severe maxillary atrophy complicates implant rehabilitation due to limited bone support and sinus pneumatization. The All-on-4 protocol provides predictable results, while zygomatic implants may offer a graftless alternative. This study compared conventional All-on-4 with a modified protocol using 2 zygomatic and 2 conventional implants. Methods: Twenty-four patients with edentulous atrophic maxillae were assigned to 2 groups according to anatomical suitability and treatment planning. The control group (n=12) received 4 conventional implants, and the study group (n=12) received 2 zygomatic plus 2 anterior implants. Outcomes included electromyographic (EMG) assessment of masseter and temporalis activity, as well as implant stability. Results: Both treatment modalities exhibited positive clinical and functional results throughout the follow-up duration. Implant stability values grew progressively in both groups, with no statistically significant difference observed between them. Electromyographic assessment indicated enhancement in muscle activity post-rehabilitation in both treatment cohorts, with no statistically significant differences in the majority of examined parameters. Conclusion: Within the limitations of this study, rehabilitation of the atrophied maxilla using 2 zygomatic implants combined with 2 conventional implants demonstrated acceptable clinical and functional outcomes during the evaluated follow-up period. Trial registration: ClinicalTrials.gov Identifier: NCT05108324.