Teeth loss are usually associated with alterations of extraction sockets result in obviously absorbed alveolar ridges and are often accompanied with soft tissue atrophy such as narrow keratinized tissue and a shallow vestibule.

Lack of peri-implant keratinized tissue is a potential risk to peri-implant diseases. Although the role of width of KM in maintaining peri-implant health is a controversial topic, the majority of high-level evidence has suggested that a minimum KM width (KMW) of 2 mm around the dental implants is critical to maintain peri-implant health and the long-term survival of dental implants.

This study will be carried out on patients attending outpatient clinic of Oral maxillofacial surgery and Periodontology Departments, Faculty of Dentistry. Modern University for Technology and Information, Cairo, Egypt.

P: Healthy patients with posterior missing teeth with deficient keratinized tissue to receive delayed dental implant placement I: Xenogeneic collagen membrane (XCM) simultaneous with delayed implant placement C: Free gingival graft (FGG) simultaneous with delayed implant placement O: Keratinized tissue width (KMW), graft shrinkage (GS), marginal bone loss (MBL) T- One year S- Randomized controlled clinical trial.

Eligible patients will be divided into equal proportions between control group and test group.

The control group "Group 1" will receive FGG simultaneous with implant placement The test group "Group 2" will receive XCM simultaneous with implant placement

Inclusion Criteria:

1. Adults above the age of 18 years.
2. Presence of 2mm or less of keratinized tissue width
3. Sufficient alveolar ridge width minimum of 6 mm
4. Patients with good oral hygiene as evidenced by plaque index (PI)<1 and showing cooperation or compliance with treatment.

Exclusion Criteria:

1. Patients diagnosed with periodontal diseases (Caton et al., 2018).
2. Acute active infection at implant sites
3. Patients with medical conditions that would compromise the surgical procedures; uncontrolled diabetes mellitus, taking intravenous bisphosphonates for treatment of osteoporosis and radiotherapy
4. Patients with parafunctional habits.
5. Smokers (≥10 cigarettes per day),