This prospective split-mouth randomized controlled trial compared horizontal alveolar ridge augmentation using alloplastic bone graft versus xenograft, both performed simultaneously with implant placement using the decompression technique in the posterior mandible. Outcomes included postoperative edema, pain, soft tissue healing, and horizontal bone gain at 6 months assessed by CBCT.

Inclusion Criteria:

• Bilateral mandibular posterior edentulism with indication for implant-supported rehabilitation
• Sufficient vertical bone height but insufficient horizontal bone width for implant placement
• No infection at surgical site
• Non-smoker
• No head-and-neck radiotherapy within 2 years
• No uncontrolled systemic disease (controlled systemic conditions with INR <1.2 acceptable)
• Signed informed consent

Exclusion Criteria:

• No indication for implant-supported prosthesis
• Smoker
• Active infection at surgical site
• Head-and-neck radiotherapy within 2 years
• Uncontrolled systemic disease
• Allergy to study materials
• Pregnancy
• Age under 18
• Medications interfering with surgical procedures
• History of mandibular fracture
• Contraindication to surgery determined by consultation
• Psychiatric disorder or inability to communication