Clinical, Radiographic and Histologic Assessment of the Efficacy of Schneiderian Membrane to Form Bone After Maxillary Sinus Lifting: A Randomized Controlled Clinical Trial.

Maxillary sinus augmentation is commonly performed by creating a space below the Schneiderian membrane which is further filled using autografts, bone graft substitutes, or a combination of both to allow for new bone formation. Recently, a new method called non-grafting sinus floor augmentation has been introduced as an alternative approach. This method is based on the idea of elevating the membrane and supporting it through implant insertion or the use of space-maintaining devices like titanium screws or mesh. This study was conducted to evaluate the efficacy of new bone formation after sinus floor elevation using space maintaining resorbable pins without graft material.

A randomized control trial was performed on 14 patients with partially edentulous or free end saddle posterior maxilla. The patients were divided randomly into two groups. Both groups underwent maxillary sinus open lifting procedure and augmentation using xenograft \* as group A and in group B the sinus membrane was elevated and stabilized by resorbable pins\*\* to maintain the created space stable and without grafting. The study was a double blind one (participants and out¬come assessors were blinded throughout the study).

All the surgical procedures were carried out un¬der local anesthesia using infraorbital and posterior superior alveolar nerve block with palatal infiltration. Full thickness mucoperiosteal flap was elevated to expose the lateral wall of the maxillary sinus. Then the maxil¬lary sinus floor elevation using the lateral window technique was performed. A bone window was outlined using a no. 8 diamond bur mounted on straight hand piece with copious irrigation (sterile saline solution) with cautious taken to not penetrate the sinus membrane. The process of bone removal was done through the cortical bone to reach the membrane without perforation. Complete osteotomy along the boundary of the osseous window until the Schneiderian mem-brane. The Schneiderian membrane was carefully elevated till the desired height.

xenograft Preparation: (control group/ group A)

Xenograft was mixed with saline followed by the protocol of graft packed and compacted against inferior walls and to the sides of the antrum until the new available volume created was filled. The lateral window was covered by collagen membrane before flap closure. Resorbable pins (test group/ group B):

In the study group: 2.0 mm screws were fixed to the lateral wall of the sinus above the superior osteotomy and placed buccopalatally where the schneiderian membrane was elevated and maintained. Then the soft tissue flap was readapted and sutured using continuous and interrupted sutures (3-0 resorbable vicryl)

Eligibility Criteria:
Inclusion Criteria:

1. Adult male/female patients above the age of 25.
2. Patients with one or more teeth requiring implant supported dental restoration in atrophic maxilla (unilateral or bilateral).
3. Alveolar bone height less than 4 mm at the defective site.
4. Good oral hygiene.

Exclusion Criteria:

1. Medically compromised patients with conditions contraindicating surgery (eg. uncontrolled diabetics, bisphosphonate intake, radio or chemotherapy).
2. Patients with active infection at or related to the site of surgery (eg. acute sinusitis).
3. Heavy smokers.
4. Patients not indicated for an implant supported restoration at the time of enrollment (eg. active/untreated periodontal disease).