• Histology:
• Relative amount of newly formed bone, graft residues, bone marrow, residual bone and connective tissue.
• Clinical parameters:
• complications during surgery related to the material.
• post-operative complications.
• Max torque for implant insertion.
• short-term implant survival (up to one year post loading)

The aim of this clinical study is to compare the amount of newly formed bone after bone augmentation with Bio-Oss® (BO) 0.25-1 mm vs. Bio-Oss® (BO) 1-2 mm in the sinus floor augmentation procedure bilaterally in 8 patients.

Hypothesis:

There is no difference in the relative amount of newly formed bone plus BO between the large (1-2 mm) and small (0.25 - 1 mm) granules.

the use of bovine bone mineral particles (Bio-Oss®)in sinus floor augmentation is well established. bovine bone mineral is an oseoconductive material which serves as a space maintainer and a scaffold for bone augmentation. the commercial product is manufactured in two different particles sizes, "large"1-2 mm, and "small"0.25-1 mm.

Comparison: the histologic characteristics of augmented bone after the use of Bio-Oss® (BO) with particle size of 0.25-1 mm vs. Bio-Oss® (BO)with particle size of 1-2 mm.

Inclusion Criteria:

• The patients included in this study are over 18 year old men and women.
• The patient must be a candidate for sinus floor augmentation.
• The patient is able to comply with the study-related procedures such as exercising good oral hygiene and attending all follow-up procedures.
• The patient is able to fully understand the nature of the proposed surgery and is able to provide a signed informed consent.

Exclusion Criteria:

• Pregnant women.
• People who smoke more than 10 cigarettes a day.
• Alcohol and drug abusers.
• People suffering from uncontrolled diabetes, severe osteoporosis, rheumatic arthritis, precancer or neoplastic lesions of oral cavity.
• The patient is nursing.