In this split-mouth controlled study, implants placed using the alveolar ridge expansion technique will be compared to those placed in native bone with sufficient horizontal bone width.

The Piezosurgery device and Bone expanders (Mectron,Italy) will be employed in an alveolar ridge expansion technique.

The success rate of endosseous implant placement in native bone has been proven to be highly predictable. Reliable long term result requires sufficient bone thickness surrounding the implant's body. This is especially true in the maxillary aesthetic zone where buccal bone thickness of 2mm or more is necessary to prevent loss of buccal bone margin and maintain the integrity of the gingival architecture.

Ridge expansion technique, an alternative to bone graft, widens the alveolar ridge prior to implant placement, thus permits the preservation of buccal and lingual bone thickness.

Narrow atrophy edentulous alveolar ridges (study site) in the maxillary aesthetic zone will be split lengthwise using piezo-electric surgery (Piezosurgery, Mectron, USA). The prepared osteotomy will subsequently be expanded using threaded osteotomes (Bone Expanders, Mectron, Italy). Implants will immediately be inserted in the prepared osteotomy. In the edentulous alveolar ridges with sufficient thickness (controlled site) in the maxillary aesthetic zone, implants will be placed directly using conventional drilling technique. Outcome measures will be compared.

Inclusion Criteria:

• At least 18 years of age
• Systemically healthy
• Implant therapy will be the elective treatment option.
• The alveolar ridge thickness will be insufficient to receive implant of 3.5-4.3mm in diameter.
• The ridge width will be at least 4mm
• Implants will be placed in the maxillary edentulous ridge from second premolar to the opposite second premolar.
• There will be a second edentulous ridge in the same individual's mouth that serves as control site. The crest of this site will be at least 5.5mm wide, sufficient to receive an implant of 3.5-4.3 mm in diameter.
• Demonstrated ability to maintain oral hygiene
• Willingness and ability to commit to follow-up
• Able to understand study procedure and provide signed informed consent.
• In order to ensure optimal efficacy of the methods used to reduce the risk of pregnancy in female subjects and potential harm to a fetus, contraceptive measures are required in order to participate in the Study, as follows: hormonal methods and the IUD must be in used at least 30 days prior to Study drug administration; that barrier methods must be use in used at least 15 days prior to Study drug administration; that vasectomy must be completed 3 months prior to first Study drug administration; or in the alternative that a 0 sperm count will suffice.

Exclusion Criteria:

• Extreme alveolar ridge atrophy with no cancellous bone between the buccal and palatal cortical plates
• Extensive vertical ridge resorption which requires vertical augmentation
• Uncontrolled periodontal disease.
• Need of sinus lift procedures in the site of intended implant placement.
• Recent febrile illness (within 6 months) that precludes or delays participation
• Wearers of pacemaker.
• Severe renal or liver diseases
• History of radiotherapy of the head and neck region
• Chemotherapy for treatment of malignant tumors at the time of the study.
• Immuno-compromised patients
• Patients on IV bisphosphonates or on long term oral bisphosphonates for more than 3 years.
• Use of disallowed concomitant medications.
• Pregnancy or intending to conceive during the course of the Study.