Background/Objectives: This retrospective study evaluated the dimensional behavior of an alveolar ridge preservation approach based on the placement of a subperiosteal heterologous cortical collagenic bone lamina without the use of particulate grafting material under routine clinical conditions. Methods: Seventy consecutive patients, each contributing one extraction site, were included. All sites were treated with a cortical lamina placed on the buccal aspect of the socket immediately after tooth extraction. Cone-beam computed tomography scans were obtained before extraction and after approximately 6 months of healing. Crestal width and vertical dimensions at the buccal, central, and lingual aspects were measured. An exploratory subgroup analysis was also performed according to the tooth region. Results: Over a mean follow-up period of 6.1 ± 1.4 months, the mean crestal width decreased from 8.4 ± 2.8 mm to 7.9 ± 1.8 mm, corresponding to a mean reduction of −0.6 ± 2.0 mm (p = 0.001). The central vertical measurement showed no significant change (0.4 ± 2.6 mm; p = 0.531). Buccal height remained stable, whereas lingual height showed a small reduction (−0.6 ± 1.7 mm; p = 0.005). The exploratory subgroup analysis revealed a width change of −0.3 ± 1.6 mm for anterior sites and 0.1 ± 2.0 mm for premolar sites while a more pronounced reduction in ridge dimensions was observed at molar sites (−2.2 ± 1.6 mm). Conclusions: The cortical lamina approach was associated with limited post-extraction dimensional changes and may represent a useful option for alveolar ridge preservation without the use of particulate grafting material, although less favorable dimensional stability may be expected in molar regions.