Radiographic and Histological Assessment of GBR Using DBB Compared to Spontaneous Bone Regeneration of Maxillary Defects , Resulted from Enucleation of Intra-bony Cystic Lesions

Two groups of patients with maxillary defects resulted from enucleation of intra-bony cystic lesions One will be subjected to guided bone regeneration while the other 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 68 mg/1.7 ml + adrenaline 0.017 mg/1.7 ml 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 Study 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:

* proper decompression of soft tissue will be applied to achieve tension-reduced suture.
* Primary closure will be performed using 4-0 vicryl sutures.
* Sutures will be removed one week 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 one week, then at the sixth months to evaluate the bony healing.

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

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

Eligibility Criteria:
Inclusion Criteria:

* Pathological Maxillary intra-bony defects with diameter ranging from 1.5 to 4.0 cm.
* patients indicated for implant placement after teeth extraction.
* Age range from 20-50 years.
* Patients free from any systemic conditions and bone metabolism diseases that might interfere with the surgical intervention, soft tissue or hard tissue healing.
* No evidence of acute inflammation.
* Regular attendance at control visits.

Exclusion Criteria:

* Pregnancy or lactation.
* Systemic conditions that compromise bone healing such as : uncontrolled diabetes mellitus, history of chemotherapy or radiotherapy or Hematological disorders.
* Patients taking bisphosphonates, glucocorticoids or other drugs that may interfere with bone metabolism.
* presence of infection at the surgical site.
* infected cysts and odontogenic keratocyst.