Soft tissue augmentation at immediate implants using a novel xenogeneic collagen matrix in conjunction with immediate...

Collagen matrices used around immediate implants may reduce morbidity although there is limited evidence on their performance.

To evaluate soft and hard tissue changes when combining immediate implants, hard and soft tissue grafting, and an immediate provisional restoration.

In 12 patients, immediate implants were placed in the anterior maxillary and first premolar area together with a xenogeneic bone substitute. Then a xenogeneic collagen matrix was placed under the buccal mucosal margin with an immediate provisional restoration. Study casts and clinical measurements were taken before extraction (Baseline/BS) at 6 months (6M) and 12 months (1Y) after implant placement. Files from the scanned casts were matched to calculate the linear and volumetric changes at the buccal tissues. Cone Bean Computed Tomographies (CBCTs) were taken prior to extraction and at 6M. The superimposed DICOM files allowed for assessing hard tissue changes and the superimposition of DICOM and STL files allowed for evaluating of soft tissue thickness at BS and 6M.

After 6 months, the horizontal tissue contours decreased 0.66 ± 0.57 mm, concomitant with a horizontal bone loss of 1.31 ± 1.32 mm, measured 1 mm below the most coronal aspect of the ridge. In contrast, the soft tissue thickness, 1 mm below the gingival margin, increased 0.75 ± 1.12 mm. At 1-year, tissue contours had decreased 1.01 ± 0.67 mm compared to BS reaching statistical significance. The mean volume loss after 1Y was 20.43 ± 11.70 mm³ while the mean mucosal margin recession was 0.86 ± 0.67 mm. These changes had a limited clinical impact as the PES Scores remained stable.

The tested protocol resulted in a significant reduction of the tissue contours and osseous ridge dimensions that was partially compensated by a non-significant increase in soft tissue thickness.