Volumetric and linear changes at dental implants following grafting with volume-stable three-dimensional collagen matrices or autogenous connective tissue grafts: 6-month data.

OBJECTIVES: The objective of this study was to test whether or not soft tissue augmentation with a volume-stable collagen matrix (VCMX) leads to similar volume gain around dental implants compared to autogenous subepithelial connective tissue graft (SCTG).

MATERIALS AND METHODS: In 12 adult beagle dogs, immediate implants were placed with simultaneous guided bone regeneration. After 25-45 weeks, soft tissue augmentation was randomly performed using VCMX, SCTG, or a sham-operated control. Impressions were taken pre-op and post-op (tissue augmentation) and again at sacrifice after healing periods of 4, 8, and 24 weeks. They were then digitized to allow for superimposition. Values of linear and volumetric changes were calculated.

RESULTS: The median increase (pre-op to post-op) in buccal volume measured 0.92 mm for VCMX, 1.47 mm for SCTG, and 0.24 mm for SH. The values (pre-op to sacrifice) were - 0.25 mm for VCMX, 0.52 mm for SCTG, and - 0.06 mm for group SH. The median ridge width 2 mm below the crest measured - 0.26 mm for VCMX, 0.53 mm for SCTG, and - 0.15 mm for SH (pre-op to sacrifice).

CONCLUSIONS: Volume augmentation using VCMX and SCTG resulted in an increase in ridge dimension (pre- to post-op). During the follow-up, the volume decreased in all three groups to a level close to the situation prior to surgery.

CLINICAL RELEVANCE: Soft tissue volume augmentation around dental implants is usually performed using the patient's own tissue. This therapy is associated with an increased morbidity due to a second surgical site. Soft tissue volume at implant sites can be augmented using VCMX and SCTG. The gain on top of the ridge appears not to be stable during the follow-up in both groups.