Fourteen patients having anterior maxillary undercut defect were selected to match a list of inclusion and exclusion criteria.

The participants were randomly allocated using a computer system into two groups:

Group A undergo inverted U-shaped maxillary ridge splitting using piezotomes with simultaneous implant placement in the same surgery.

Group B undergo inverted U-shaped maxillary ridge splitting as a first stage and after four weeks, ridge expansion and implant placement will be performed with only envelop flap.

Assessment included measurements of bone gain at the undercut defect and bone density labial to implants in each group from the cone-beam computed tomography

Inclusion criteria

• Adult patients (20-45) years of age with no sex predilection
• At least one tooth missing in the anterior maxilla
• The presence of a labial undercut >2 mm in thickness which is not able to house an implant
• The presence of adequate bone width near the alveolar bone crest
• The absence of a vertical bone defect.

Exclusion criteria

• History of any systemic disease that would contraindicate surgery example uncontrolled diabetes.
• Pregnancy or lactation.
• Long-term amino-bisphosphonate therapy.
• Smoking more than 10 cigarettes per day.
• Alcohol or drug abuse.
• Uncontrolled periodontal disease.
• Active infection.
• Inadequate inter-incisal space.
• Bruxism or clenching.