Enhancing Soft Tissues Around Inserted Implants by Two Different Methods

Evaluation of Xenogeneic Collagen Matrix Versus Connective Tissue Graft to Enhance Soft Tissue Profile Around Single Dental Implants in the Aesthetic Zone

This randomized controlled clinical trial investigates the efficacy of xenogeneic collagen matrix (XCM) versus autogenous subepithelial connective tissue graft (SCTG) in enhancing the peri-implant soft tissue profile around single dental implants in the aesthetic zone of the anterior maxilla. Thirty adult patients with a single missing tooth, adequate bone volume, and sufficient keratinized tissue will be recruited at Damascus University. Each patient will undergo a fully digital workflow for implant planning-including CBCT imaging, intraoral scanning, and CAD/CAM fabrication of a surgical guide and provisional restoration-to ensure precision in implant placement. Immediately following implant insertion, patients will be randomly allocated (1:1) to either receive a CTG harvested from the palatal mucosa using a single incision technique or an XCM (Mucoderm®, Botiss Biomaterials) that is adapted and secured to the buccal mucosa. The primary outcome is the increase in buccal soft tissue profile, measured via superimposed digital surface models at baseline, immediately postoperatively, and at 3 months. Secondary outcomes include patient-reported measures (pain, edema, aesthetic satisfaction), clinical parameters (keratinized tissue width, soft tissue height), peri-implant health assessments, and radiographic assessment. By comparing these two methods, the study aims to determine whether the less invasive XCM can offer outcomes comparable to the CTG standard while reducing donor site morbidity and overall surgical time.

This clinical trial is designed to evaluate and compare the performance of two soft tissue augmentation techniques-autogenous subepithelial connective tissue graft (CTG) and xenogeneic collagen matrix (XCM, Mucoderm®)-when used concurrently with dental implant placement in the aesthetic zone of the anterior maxilla. The rationale for this study stems from the clinical challenge of achieving optimal soft tissue esthetics and function following tooth loss. While CTG has long been considered the gold standard for increasing peri-implant soft tissue thickness, it requires a secondary surgical site, which may lead to donor site morbidity, limited tissue availability, and increased surgical time. In contrast, XCM offers a promising alternative that is biocompatible, readily available, and less invasive.

Patients aged 18 years or older with a single missing tooth in the aesthetic zone, adequate bucco-palatal bone (≥6 mm), and at least 5 mm of keratinized tissue width will be considered eligible for the study. The enrollment process begins with a thorough screening process involving clinical and radiographic examinations, including a low-dose, small-field CBCT scan and an intraoral scan. These imaging modalities allow for accurate digital implant planning using specialized software, ensuring optimal implant positioning. The digital data will be used to fabricate a stereolithographic surgical guide and design a custom CAD/CAM screw-retained provisional restoration.

Following successful screening and informed consent, the surgical phase commences. Under local anesthesia, a full-thickness flap is elevated at the implant site. Guided by the digital plan, a dental implant is precisely positioned using the surgical guide. At this point, participants are allocated to one of two intervention groups based on a strict randomization protocol.

In the CTG group, a connective tissue graft is harvested from the palatal mucosa using the de- epithelialized free gingival graft technique. The harvested graft is then trimmed to match the dimensions of the recipient site and carefully positioned under the elevated flap to augment the soft tissue. The donor site is sutured using gelatin matrix to ensure proper healing. This technique, while effective, is associated with postoperative discomfort and additional surgical time due to the need for a second operative site.

Conversely, in the XCM group, soft tissue augmentation is achieved using a xenogeneic collagen matrix (Mucoderm®). The graft, initially measuring 15 × 20 mm, is first moistened in saline for 10 minutes and slightly compressed to adapt its thickness to the defect. After a superficial incision to release any muscle tension, the XCM is accurately positioned and secured to the buccal mucosa using single sutures. Following soft tissue augmentation, a screw-retained provisional restoration is attached immediately, contributing to both function and esthetics during the healing phase.

The primary outcome of the study is the increase in the buccal soft tissue profile, quantitatively assessed using intraoral scans to generate digital surface models at three critical time points: preoperatively (T0), immediately after surgery (T1), and 3 months postoperatively (T2). Secondary outcomes include clinical assessments-such as probing depth, plaque index, bleeding on probing, keratinized tissue width, graft dimensions, wound closure, surgery time, and complications-as well as radiographic evaluation of marginal bone loss. In addition, patient-reported outcome measures (PROMs), including postoperative pain, swelling, aesthetic satisfaction, and willingness to undergo the same treatment again, will be recorded using validated visual analogue and Likert scales. Aesthetic outcomes, including mid-facial recession, Pink aesthetic score, and mucosal scarring index, will also be documented.

The data will be analyzed on an intention-to-treat basis by an independent statistician. Statistical comparisons between the two groups will help determine whether the xenogeneic collagen matrix offers comparable or superior results to the autogenous connective tissue graft regarding soft tissue volume augmentation, esthetic outcomes, and patient satisfaction. Ethical approval has been obtained from the University of Damascus, and the trial follows the CONSORT guidelines. The results will be disseminated through peer-reviewed publications and presentations at professional conferences, contributing valuable evidence to the field of implant dentistry.

Overall, this study is expected to provide insight into whether XCM can serve as a reliable, less invasive alternative to CTG, thereby potentially enhancing patient outcomes and reducing the complications associated with donor site morbidity.

Inclusion Criteria:

• Aged 18 years or older.
• Good oral hygiene, defined as full-mouth plaque score ≤25%.
• Having a single missing tooth in the aesthetic zone of the maxilla.
• Tooth extraction occurred at least 3 months prior to enrolment.
• Having adequate bone volume for implant placement (bucco-palatal bone dimension of at least 6 mm).
• Having at least 5 mm of keratinized tissue width at the implant site.

Exclusion Criteria:

• Systemic diseases.
• Smoking.
• Periodontal disease.
• Untreated caries lesions.
• Need for horizontal bone augmentation at the time of implant placement.