Two groups of patients with maxillary defects resulted from enucleation of intra-bony cystic lesions the 1st group will be subjected to guided bone regeneration while the second group will be subjected to spontaneous bone regeneration.

• Two groups of patients with maxillary cystic lesions indicated for enucleation. One will be subjected to guided bone regeneration while the other will be subjected to spontaneous bone regeneration.

• General pre-operative procedures:

  • All patients will undergo appropriate preparation involving periodontal therapy , proper oral hygiene measures in addition to endodontic treatment for the non-vital teeth related to the lesion.

intraoperative procedure: (both groups)

• Scrubbing and draping of the patient will be carried out in a standard fashion using betadine surgical scrub.
• Local anesthesia will be administered (Articaine hydrochloride 4% with Epinephrine 1:100,000) injectable solution.
• Flap design: a sulcular incision will be done , extending two teeth beyond the area of interest followed by two oblique incisions on either side of the flap. A full thickness mucoperiosteal flap will be raised to expose the area occupied by the lesion.
• After flap reflection, the exposed bone related to the lesion will need to be removed to provide adequate accessibility before enucleation of the lesion.
• The specimens will be fixed in 10% formalin for pathological examination.

Intra-operative procedures - continued in first Group (GBR group) The intra-bony defect will be filled with Deproteinized Bovine Bone. In Both groups: Titanium mesh will be tailored with 3mm overlap at the edges to cover the bone window completely and fixed to the bone using mono-cortical titanium screws.

This is followed by Primary closure using 4-0 vicryl sutures that will be removed 10 days postoperatively.

Postoperative medications:

For both groups, postoperative antibiotic course of amoxicillin+ clavulanic acid 1 g tab (Augmentin) will be prescribed for one week and isobutylphenylpropionic acid 600 mg tab (Brufen) twice daily for one week. One shot of dexamethasone 8 mg vial will be administered intramuscularly immediately after the surgery together with ketorolac tromethamine 30 mg .

Postoperative care and instructions:

• Cold compresses will be applied for 10 minutes every 30 minutes for the first 24 hours postoperatively replaced by warm fomentation with the same rate for the next two days.
• Patients will be advised to maintain good oral hygiene and oral hygiene rinses using 2% chlorohexidine gluconate mouth rinse for a week starting from the second postoperative day (three times daily)
• Soft diet is recommended for the first 48 hours.
• The patients will be recalled after two days, after one week, at the end of the first month and then at three and six months to monitor the soft tissue healing where the sutures were removed after 10 days , then at the sixth months to evaluate the bony healing.

Radiographic assessment will be achieved by CBCT scan preoperatively, immediately postoperative ,and 6 months postoperatively to evaluate the change in the bone density . A total of three scans will be taken for each patient.

In the second group, the amount and percentage of bone gain will be measured based on the CBCT scans .

in the 6 months after the surgery ,titanium mesh and the screws will be removed and core biopsy will be taken for histological assessment.

dental implant/s will be placed in cases indicated for implantation.

Inclusion Criteria:

1. Presence of a well-defined pathological cystic lesion involving the maxilla, confirmed clinically and radiographically that require surgical enucleation resulting in an intra-bony defect.
2. Mesiodistal dimension of the defect ranging from 1 cm to 4.0 cm.
3. Patients aged 20 to 50 years, of either sex.
4. Patients medically fit for surgical intervention under local or general anesthesia (ASA I or II)
5. Absence of systemic conditions affecting bone healing (e.g., uncontrolled diabetes, osteoporosis)
6. Patients willing to participate in the study and able to provide informed written consent.
7. Availability of adequate postoperative follow-up (minimum of 6 months).

Exclusion Criteria:

1. Pregnant or lactating women.
2. Radiographically, Presence of multi-locular or aggressive lesions suggestive of odontogenic tumors (e.g., ameloblastoma)
3. Patients with compromised immune status (e.g., HIV, long-term corticosteroid therapy)
4. History of allergic reaction to any of the surgical materials used (e.g., titanium, bovine bone graft).
5. Patients participating in another clinical trial or receiving investigational therapy during the study period.
6. Presence of acute infection at the surgical site.
7. cysts with a known high recurrence rate such as Odontogenic keratocysts (OKC).

This trial is considered a randomized single blind clinical trial due to the following:

• The participants will be blinded to the technique that will be used during the surgical procedure.
• The operator will not be blinded for both techniques during the surgical procedure as the two techniques are different.
• The outcome assessor cannot be blinded.