Structural and histological differences between connective tissue grafts harvested from the lateral palatal mucosa or from the tuberosity area

Abstract

Summary: Tuberosity grafts had a greater percentage of lamina propria and lower percentage of submucosa when compared to lateral palate grafts. Objective: The study aims to understand the differences in the structural composition of soft tissue autografts harvested from the lateral palate or the tuberosity.

Material and methods: Patients were randomly allocated to receive autografts harvested either from palatal or tuberosity sites to augment horizontal volume deficiencies around single-tooth implants. Tissue biopsies were analyzed for histological and histo-morphometric analysis. Picro-sirius red stain was used to evaluate collagen 1 and 3. Also, immuno-histochemical analysis was performed against MMP1, MMP2, cytokeratin-10, cytokeratin-13, and lysine hydroxylase-2.

Results: Twenty specimens were harvested from 9 subjects in the lateral palate group (PG) and 11 subjects in the tuberosity group (TG). The percentage of lamina propria represented 51.08% in the PG group and 72.79% in the TG group, while the area of submucosa was minimal in the TG group representing 4.89% of the total sample vs 25.75% in the PG. The total area of COL-1 and 3 in the TG was 1.19 ± 0.57 and 0.72 ± 0.44 mm2, respectively, while in the PG, the corresponding values were 1.4 ± 0.7 and 1.04 ± 0.5 mm2. The immuno-histochemical analysis generally showed a higher expression of LLH-2, MMP2, CYT-10, and CYT-13 in the TG when compared with the PG.

Conclusion: Tuberosity grafts had a greater percentage of lamina propria and lower percentage of submucosa. The collagen content in the lamina propria was similar for both groups while the immuno-histochemical profile showed differences in the antibody expression of the epithelial cells. Clinical relevance: Tuberosity grafts had more lamina propria and less submocusa, which may be beneficial for volume augmentation.