A multi-centre randomized controlled trial comparing connective tissue graft with collagen matrix to increase soft tissue thickness at the buccal aspect of single implants: 3-Year results.

Abstract

To compare connective tissue graft (CTG) with collagen matrix (CMX) in terms of increase in buccal soft tissue profile (BSP) when applied at single implant sites. Patients with a single tooth gap in the anterior maxilla and horizontal mucosa defect were enrolled in a multi-centre randomized controlled trial. All were fully healed sites with a bucco-palatal bone dimension of at least 6 mm, and received an immediately restored single implant using a full digital workflow. Patients were randomly allocated to the control (CTG) or test group (CMX: Geistlich Fibro-Gide, Geistlich Pharma AG, Wolhusen, Switzerland) to increase buccal soft tissue thickness. Primary endpoints were increase in BSP at T1 (immediately postop), T2 (3 months), T3 (1 year) and T4 (3 years) based on superimposed digital surface models. Secondary endpoints included patient-reported, clinical and aesthetic outcomes. Thirty patients were included per group (control group: 15 males, 15 females, mean age 50.1 years; test group: 14 males, 16 females, mean age 48.2 years) and 50 could be re-examined at T4. The changes in BSP over time were significantly different between the groups (p < .001). At T4, the estimated mean increase in BSP amounted to 0.83 mm (95% confidence interval [CI]: 0.58-1.08) in the control group and 0.48 mm (95% CI: 0.22-0.73) in the test group. The estimated mean difference of 0.35 mm (95% CI: 0.06-0.65) in favour of the control group was significant (p = .021). No significant differences between the groups could be observed in terms of patients' aesthetic satisfaction (p = .563), probing depth (p = .286), plaque (p = .676), bleeding on probing (p = .732), midfacial recession (p = .667), Pink Esthetic Score (p = .366) and Mucosal Scarring Index (p = .438). However, CMX resulted in significantly more marginal bone loss (-0.43 mm; 95% CI: -0.77 to -0.09; p = .015) than CTG. CTG was more effective in increasing buccal soft tissue profile and resulted in less marginal bone loss than CMX. Therefore, CTG remains the gold standard to increase soft tissue thickness at implant sites. This study was registered in ClinicalTrials.gov (NCT04210596).