Abstract
Objective
To compare connective tissue graft with thick and thin acellular dermal matrices in a modified vestibular incision subperiosteal tunnel access–based procedure, using gingival thickness at the selected target site 18 months postoperatively as the primary endpoint.
Methods
In this single-center exploratory randomized trial, 36 adults with recession type 1 gingival recession were allocated in a 1:1:1 ratio to connective tissue graft, thick acellular dermal matrices (1.0–1.2 mm), and thin acellular dermal matrices (0.4–0.6 mm) groups. Longitudinal continuous outcomes were analyzed using linear mixed models. Pairwise comparisions at 18 months were performed using Welch tests with within-outcome Bonferroni adjustment. Postoperative visual analogue scale pain scores and Landry healing scores were analyzed nonparametrically. Missing-data scenarios and two one-sided tests were post hoc.
Results
Among the 47 individuals assessed, 11 were excluded and 36 were randomized (12 per group); 18-month primary-endpoint data were available for 35 patients. The mean (SD) gingival thickness was 1.708 (0.334) mm in the connective tissue graft group, 1.708 (0.450) mm in the thick acellular dermal matrices group, and 1.273 (0.410) mm in the thin acellular dermal matrices group. The mean gingival thickness in the connective tissue graft group exceeded that in the thin acellular dermal matrices group by 0.436 mm (95% confidence interval: 0.108 to 0.763; adjusted
p
= 0.036); the difference in the gingival thickness between the thick acellular dermal matrices and thin acellular dermal matrices groups was not statistically significant after adjustment (adjusted
p
= 0.073). Connective tissue graft and thick acellular dermal matrices groups had comparable observed means; however, the trial was not powered for equivalence. Postoperative visual analog scale scores were lower in both acellular dermal matrices groups than in the connective tissue graft group, and thin acellular dermal matrices group had a higher day-7 healing score than the thick acellular dermal matrices group.
Conclusions
The 18-month gingival thickness was greater in the connective tissue graft group than in the thin acellular dermal matrices group after multiplicity adjustment, whereas the mean values of the connective tissue graft and thick acellular dermal matrices groups were comparable. The study did not establish equivalence, and the root-coverage estimates were too imprecise to demonstrate comparability. Acellular dermal matrices avoided palatal donor-site harvesting and were associated with lower postoperative visual analog scale pain scores.
Trial registration
Chinese Clinical Trial Registry (WHO Primary Registry), ChiCTR2600124861.