OBJECTIVE When the bone ridge is corticalized, the displacement of the buccal plate may result in an unintentional malfracture. The aim of this study was to report the results of a 2-stage atrophic alveolar ridge expansion performed with a sonic-air surgical instrument. METHODS In this retrospective cohort study, the atrophic distal segments of the mandible were treated by a split-thickness flap approach and application of an alveolar ridge expansion performed in 2 surgical phases. A sonic-air surgical instrument was used. In the first surgical procedure, only basal corticotomies on the buccal plate were performed. In the second stage, sagittal and vertical osteotomies were added, aiming to facilitate the displacement of the buccal bone plate. Subsequently, implants were installed into the created space between the buccal and lingual plates. No bone substitutes were used. The width of the displaced buccal bone wall and the gaps that occurred mesially and distally to the implant were measured at the time of implant installation. Cone beam computed tomography scans were taken before the first and after the second surgical procedures, and the width of the alveolar crest at both observations and the width of the residual mesial and distal gaps after implant installation were measured. RESULTS We included 10 patients (6 women and 4 men; aged 37 to 69 years) in the study, and 15 implants were installed in expanded narrow ridges. Clinically, the mean width of the buccal bone wall was 1.2 ± 0.2 mm and the gaps ranged between 2.8 and 3.2 mm. On the radiographic assessments, the mean initial width of the alveolar bone crest measured 4.1 ± 0.5 mm, reaching 6.8 ± 0.9 mm after ridge expansion (P < .01). CONCLUSIONS The use of a modified edentulous ridge expansion in 2 stages allowed the installation of implants in narrow and corticalized alveolar ridges. We suggest that this technique is especially applicable in the distal segments of the mandible because of the low invasiveness, low risk of buccal plate fractures, reduced morbidity, and reduced costs.