The aim of this case series is to evaluate the outcomes of horizontal ridge augmentation performed using a combination of demineralized freeze-dried bone allograft layered with xenograft bone with a resorbable native collagen membrane.

The aim of the study is to evaluate the outcomes of horizontal gone gain when demineralized freeze dried bone allograft (DFDBA) and xenograft are used in a layering technique.

Primary objectives are to compare the bone gain after the bone augmentation procedure. Secondary outcomes are to study the vital bone percentage formation after the bone augmentation procedure and to study the amount of shrinkage of the graft material observed after the procedure.

Test group will consist of patients receiving horizontal ridge augmentation using a combination of DFDBA layered with xenograft particulate bone using a resorbable collagen membrane. Surgical procedure is describe under assigned interventions.

Follow up and implant placement:

The patients will be followed up at 1-2, 3-5 and 6-8 weeks to assess the surgical site for healing. Following this, the patient will be allowed to heal for a period of 6-9 months at which point a cone beam computed tomography (CBCT) will be taken to evaluate the bone gain after horizontal ridge augmentation.

CBCT Measurements:

The images obtained from the CBCT scan will be transferred to a digital CBCT viewing software in which measurements will be carried out. The anatomical landmarks and adjacent teeth will be identified and used to orient the scan to get an image representing the buccal-palatal plane of the area of interest. The horizontal bone gain will be measured at 3,5,7 mm from the crest. Additionally, the amount of graft shrinkage will be measured between immediate post-operative CBCT and follow up CBCT.

Bone core biopsies:

Following at least 6 months of healing and follow up, patients will be appointed for implant placement. At this visit a full thickness flap will be raised. If anatomical considerations and space permits, a bone core biopsy will be obtained using a trephine and stored in formalin for histologic and histo-morphometric analysis. The harvesting of a bone core is considered additional for the study. It will only be performed if it is safe to do so and the harvesting of the core will not jeopardize the long-term longevity of the implant placement (not all patients that are part of the study will undergo the harvesting of a bone core). This bone core will be saved for histologic analysis.

Histologic preparation and evaluation:

Following the bone core removal, the biopsied specimens will be stored until further evaluation. The bone core biopsies will be prepared and evaluated at a lab. De-identified samples will be shipped to the lab for further analysis. Briefly, the biopsy will be dehydrated in a series of ethanol baths. Following this, it will be infiltrated in xylene and methyl metha-acrylate. Following embedding, the bone samples will be sectioned using a hard tissue microtome and stained with hematoxylin-eosin. The quantitative assessment of percentage vital bone, graft particles and connective tissue will be measured using a grid under magnification.

Inclusion Criteria:

Patients at least 18 years of age Patients requiring horizontal bone augmentation prior to implant placement ASA I or ASA II patients Non-smoker Patients willing to be followed up for a period of 6-9 months Patients must be physically able to tolerate conventional surgical procedure or procedures under IV moderate sedation.

Exclusion Criteria:

Patients with uncontrolled diabetes Patients with history of radiation to the jaw Patient with immune compromise due to disease or medication Patients requiring primarily vertical bone augmentation prior to implant placement Patients taking bisphosphonates Patients with HIV or hepatitis infection Patients who are known to be pregnant or planning to within 6 months of study enrollment Patients with a history of a failed implant in the site. Patients with an active infection or pathology in the site of treatment that need to be treated prior to bone augmentation Patients with a history of untreated generalized chronic periodontitis Patients who are unable to provide consent and require a legally authorized representative to sign on their behalf