Guided Bone Regeneration in Lower Posterior Edentulous Arch Using Resorbable or Non Resorbable Membrane.

Inclusion Criteria: * Mandibular posterior atrophic alveolar ridge Required horizontal bone augmentation procedures prior to implant placement. * Alveolar bone height suitable for implant placement. * Free of any local or systemic condition that may contraindicate ridge expansion procedure * The capacity to understand and accept the conditions of the study. * Continuing participation over at least 1 year of follow-up. Exclusion Criteria: * Heavy smokers (i.e., 2 or more packs of cigarettes per day); * Insufficient oral hygiene * Acute local or systemic infection * Patients with any systemic disease that may affect bone healing; * Pregnancy or the possibility of becoming pregnant during the study; and * Addiction to drugs or alcohol