A Combined Approach Using Strip Grafts and Xenogenic Dermal Matrix for Peri-Implant Keratinized Mucosa Augmentation in the Mandible: A Case Series

<b>Background:</b> Ensuring a minimum peri-implant keratinized mucosa width (PIKM-W) is critical for maintaining dental implant health, as inadequate PIKM-W is associated with increased risks of plaque accumulation, mucosal inflammation, and peri-implantitis. While epithelialized connective tissue grafts (ECTGs) are considered the gold standard for soft tissue augmentation, they often lead to significant patient morbidity. Xenogeneic dermal matrices (XDMs) offer a less invasive alternative, but are prone to shrinkage, particularly in the mandible. The aim of this study was to evaluate a new surgical method to overcome these limitations with the combination of a narrow band of ECTG (autogenous strip graft, ASG) and an XDM to augment the PIKM-W in the posterior mandible. <b>Methods:</b> Twelve patients with a PIKM-W of less than 2 mm in the mandible underwent peri-implant soft tissue augmentation using this combined approach. Changes in the PIKM-W were measured preoperatively; immediately postoperatively; and at 1, 3, 6, 9, and 12 months. Graft remodeling (shrinkage or contraction) and PIKM thickness (PIKM-T) were also evaluated over time. <b>Results:</b> Preoperatively, the mean PIKM-W was 0.39 ± 0.40 mm and the PIKM-T was 1.36 ± 0.43 mm. At 6 months, the mean PIKM-W was 4.93 ± 0.98 mm and the PIKM-T was 2.88 ± 0.80 mm, with shrinkage of 39.2 ± 14.1%. By 12 months, the mean PIKM-W stabilized at 4.58 ± 1.28 mm and the PIKM-T stabilized at 2.83 ± 0.65 mm, with shrinkage of 42.2% ± 16.8%. <b>Conclusions:</b> There were statistically significant differences in clinical parameters between the baseline and 6 and 12 months (<i>p</i> < 0.05). This technique demonstrated the potential for stable augmentation of PIKM-W and PIKM-T over time, with manageable shrinkage. However, further studies with larger sample sizes are needed to confirm its clinical efficacy as an alternative for mandibular keratinized mucosa augmentation around implants.