The Effect of Different Gingival Phenotypes on Keratinized Tissue Augmentation Using Xenogeneic Collagen Matrix

The xenogeneic collagen matrix (XCM) is widely used for keratinized mucosa augmentation around natural teeth and dental implants due to its consistent efficacy and the advantage of avoiding a second surgical site. This study aimed to investigate the influence of different gingival phenotypes on the effectiveness of XCM in augmenting keratinized mucosa width.

Thirty-two patients with buccal keratinized tissue width (KTW) <2 mm at mandibular molar sites were enrolled and equally divided into two groups (n = 16 each). Based on the keratinized tissue thickness (KTT) measured, patients were assigned to either a thin phenotype group or a thick phenotype group. All underwent XCM-based augmentation, with gingival parameters recorded preoperatively, immediately postoperatively, and at 3- and 6-month follow-ups. KTW, KTT, and the shrinkage rate of KTW were measured.

No statistically significant differences were observed in preoperative or immediate postoperative KTW between groups (p = 0.598). At 3 and 6 months, the thick phenotype group exhibited significantly greater KTW (5.2 ± 0.67 mm vs. 3.9 ± 0.88 mm, p < 0.001; 4.7 ± 0.68 mm vs. 3.2 ± 0.65 mm, p < 0.001) and lower contraction rates (26.49 ± 7.4% vs. 44.39 ± 11.25%, p < 0.001; 33.49 ± 8.77% vs. 53.5 ± 10.08%, p < 0.001) compared with the thin phenotype group. Changes in KTT following XCM augmentation showed no significant intergroup differences (p = 0.976, p = 0.879).

XCM yields more predictable outcomes in thick gingival phenotypes than in thin phenotypes for keratinized mucosa augmentation. Over a 6-month period, thick phenotype patients demonstrate significantly reduced material contraction rates.

The gingival phenotype should be considered when planning keratinized tissue augmentation.

Chinese Clinical Trial Registry, no. ChiCTR2500100933 (last updated on 17/04/2025).