To assess efficiency of ridge preservation (in vertical and horizontal dimensions) after tooth extraction using Calcium Sulfate with hydroxyapatite(®Bond-apatite) compared to the use of bovine bone substitute (BioOss®) and to extration only as negative control.

Dental implants have become in the past ten years a popular and promising treatment in the rehabilitation of missing teeth. However, using implants depends on adequate alveolar bone volume. Anatomical restrictions are mostly present in posterior mandibular and maxillary regions. Alveolar bone loss usually occurs because of active periodontal disease, trauma or teeth extractions.

Teeth extractions are associated with some loss of alveolar bone in the horizontal and vertical dimensions. This loss is more pronounced when teeth are extracted because of periodontal disease. Bone grafts from different origins (autogenic, allogenic, xenogenic or alloplastic) can partly reduce the alveolar bone loss. Different ridge preservation techniques were succesfully used in clinical trials, using membranes only or as a combination of membranes and bone substitutes.

Synthetic bone grafts have been proven successfully for ridge preservation. Calcium sulfate is the oldest material, being in use in dentistry for more than 30 years , and in orthopedics for more than 100 years . Calcium sulfate is completely absorbed and constitutes a matrix on wich bone is able to grow (osteoconductive). It does not induce inflammation and doesn't alter calcium levels in the blood flow.Previous studies has shown that calcium sulfate is completely replaced by bone. On the other hand, fast absorption of calcium sulfates can alter the dimensional stability of the graft. Adding Hydroxy Appatite may improve stability during bone remodeling.

This study includes patients who need extractions of incisors, canines or premolars. The extraction sockets must be mostly intact with a maximum 4 mm of one wall missing in the vertical dimension.

30 patients who need extractions from region of interest, with no extended bony defects, will be enrolled from the department of Periodontology, school of graduate dentistry, Rambam Health Care Campus

Inclusion Criteria:

• Informed consent properly described and signed.
• Patients who need extractions of molars for dental or periodontal reasons.
• At least 18 years old.
• Need for future dental implants in the extraction areas.

Exclusion Criteria:

• No informed consent.
• Pregnant women.
• Women who breastfeed.
• Patients treated with drugs influencing metabolism of bone such as bisphosphonates.
• Heavy smokers (more than 20 cigarettes per day).
• Patients with dentures pressing on the area of extractions/bone grafts