Soft tissue volume augmentation at dental implant sites using a volume stable three-dimensional collagen matrix - histological outcomes of a preclinical study.

Abstract

The aim of this study was to test whether or not soft tissue augmentation with a collagen matrix (VCMX) leads to a similar increase in ridge width around dental implants compared to the use of an autogenous subepithelial connective tissue graft (SCTG). In 12 dogs, immediate dental implants were placed with simultaneous guided bone regeneration. Three months later, soft tissue volume augmentation was performed by randomly allocating three treatment modalities to these sites [VCMX, SCTG, sham-operated group (control)]. Dogs were sacrificed at 1 (n=4), 2 (n=4) or 6months (n=4). Descriptive histology and histomorphometric measurements for soft tissue thickness were performed on non-decalcified sections. The horizontal soft tissue thickness was maximal at the most coronal level (alveolar crest) at 1month (VCMX: 2.1±1.6mm; SCTG: 2.5±1.7mm; p=0.877) and decreased until 6months. At 6months, the greatest mucosal thickness was at a level 3.5mm below the crest (VCMX: 0.8±0.3mm; SCTG: 0.7±0.2mm) (p=0.754). Control sites revealed no relevant soft tissue augmentation at any level and any time-point. Tissue integration for VCMX and SCTG were favourable with minimal inflammatory reactions. Soft tissue volume augmentation at implant sites was obtained to a similar extent using VCMX and SCTG up to 2months. Thereafter, degradation and remodelling processes were enhanced leading to a minimal increase in soft tissue thickness at 6months for VCMX and SCTG.