RESUMEN
ABSTRACT: The present study investigated clinical and histomorphometric data after sinus lift procedures performed with and without mesenchymal stem cells (MSCs) added to a graft. Twenty-four patients underwent maxillary sinus lift for implant placement. Twelve patients each were assigned to control (Group 1) and test (Group 2) groups. An MSC suspension was added to the graft used in patients of Group 2. Five of 12 patients in both groups underwent crestal-approach sinus lift with immediate implant placement, while seven patients received a lateral-approach sinus lift. The MSC suspension was obtained using the Rigenera protocol. Samples from the grafted site were evaluated, processed, and stained using three staining techniques 90 days after surgery. Histomorphometric analysis was performed using an imaging software (ImageJ). Two types of tissues were defined: Type 1 'mature bone' and Type 2 'osteoid tissue'. The mean Type 1 tissue percentage was 27.24% in Group 1 and 44.45% in Group 2 (P < 0.05). The mean Type 2 tissue percentage was 10.86% and 7.04% in Groups 1 and 2, respectively. The mean Type 1 tissue percentages for the crestal approach were 24.52% for Group 1 and 50.78% for Group 2, while the mean Type 1 tissue percentages for the lateral approach were 29.18% for Group 1 and 39.92% for Group 2. Patients treated with grafts containing MSCs showed 63.18% increased bone formation compared to those treated with grafts not containing MSCs (P < 0.05). Although our data showed a positive trend in patients treated with MSCs, differences between subgroups were not significant (P > 0.05).