Dimensional changes in free epithelialized gingival/mucosal grafts at tooth and implant sites: A prospective cohort study

Background A study was made of the dimensional changes in free epithelialized gingival/mucosal grafts (FEGs) used to augment keratinized tissue (KT) at tooth and implant sites, and of the confounders influencing the dynamic changes over 6 months of follow-up. Methods A prospective cohort interventional study was made of implant and tooth sites needing KT augmentation by means of an apically positioned flap and FEG. Six intraoperative variables were recorded at baseline (T0). In addition, graft width (GW), graft length (GL), and graft dimension (GD) were assessed at 3 weeks (T1), 3 months (T2), and 6 months of follow-up (T3). Univariate and multivariate analyses were performed to explore associations between the demographic and intraoperative variables and the outcomes over the study period. Results Based upon an a priori power sample size calculation, a total of 56 consecutive patients were recruited, of which 52 were available for assessment. A total of 73 graft units were included in 122 sites. At T3, the mean change in GD in FEG was 40.21%. In particular, the mean changes in GL and GW were 12.13% and 33.06%, respectively. Statistically significant changes in GD were recorded from T0 to T1 (P < 0.0005) and from T1 to T2 (P < 0.0005), but not from T2 to T3 (P = 0.13). The change in GD at T3 was 33.26% at tooth and 43.11% at implant site level (P = 0.01). Age and GW assessed at T0 proved to be related to the changes in GD and GW in the univariate and multivariate analyses. The univariate analysis showed the avascular area (AA) to be related to the changes in GD and GW at the implant sites, whereas graft thickness (GT) was associated to changes in GD and GW at the tooth sites in the univariate and multivariate analyses. Conclusion Free epithelialized grafts are exposed to dimensional changes that result in a reduction of approximately 40% of the original graft dimension-the changes being approximately 10% greater at the implant sites than at the tooth sites (NCT04410614).