Acute Oroantral Communication Closure: Resorbable Collagen Membrane vs. Buccal Advancement Flap Outcomes (AOC)

Oroantral communication (OAC) is an abnormal opening between the oral cavity and the maxillary sinus that may occur after extraction of posterior maxillary teeth. If not treated promptly, it can lead to sinus contamination, chronic infection, and development of an oroantral fistula requiring more complex surgical management. The standard surgical treatment is closure with a buccal advancement flap (Rehrmann technique). However, this method may reduce vestibular depth, displace the mucogingival junction, and decrease the width of keratinized gingiva.

This prospective clinical study compares two surgical approaches for closure of acute OAC diagnosed within 24 hours after tooth extraction: placement of a resorbable collagen membrane beneath the mucosa versus the conventional buccal advancement flap. Clinical and radiographic parameters related to soft tissue architecture, postoperative recovery, and bone healing are evaluated during a 90-day follow-up period.

Study Overview

• Status: Completed
• Conditions: Oroantral Fistula; Oroantral Communication; Acute Oroantral Communication; Post-extraction Maxillary Sinus Communication
• Intervention / Treatment: Procedure: Resorbable collagen membrane OAC closure; Procedure: Buccal advancement flap OAC closure

Detailed Description

Oroantral communication (OAC) is a pathological connection between the oral cavity and the maxillary sinus most commonly occurring after extraction of posterior maxillary teeth. The close anatomical relationship between the sinus floor and the roots of maxillary molars and premolars increases the risk of perforation of the Schneiderian membrane during dental extraction. If an OAC is not diagnosed and treated promptly, microbial contamination of the sinus may occur, potentially resulting in chronic maxillary sinusitis and epithelialization of the tract with formation of an oroantral fistula. Early closure of acute defects within 24-48 hours is therefore generally recommended.

The buccal advancement flap described by Rehrmann is the most frequently used surgical technique for closure of acute OAC because of its technical simplicity and predictable closure of the defect. Nevertheless, advancement of the buccal mucoperiosteal flap may alter local soft tissue anatomy, including reduction of vestibular depth, displacement of the mucogingival junction, and loss of keratinized gingiva. These anatomical changes may affect oral hygiene and may complicate future prosthetic or implant therapy.

Biomaterial-based techniques that preserve soft tissue architecture represent a potential alternative approach. Resorbable collagen membranes are widely used in guided tissue regeneration and guided bone regeneration due to their biocompatibility, clot stabilization properties, and barrier function. Heterologous collagen membranes, such as Creos Xenoprotect, are designed to integrate with surrounding tissues and gradually resorb without the need for surgical removal. Their use for closure of acute OAC has been described in clinical reports; however, comparative clinical data against conventional flap techniques remain limited.

The present study is designed as a prospective, non-randomized comparative clinical investigation evaluating two surgical methods for closure of acute oroantral communications diagnosed within 24 hours after extraction of posterior maxillary teeth. Adult patients presenting with clinically and radiographically confirmed OAC are screened for eligibility and allocated to treatment according to the predefined clinical protocol.

In the experimental group, closure of the communication is performed using a resorbable heterogeneous collagen membrane (Creos Xenoprotect) placed in a submucosal position to cover the defect. Limited mucoperiosteal elevation is performed as necessary, and the membrane is stabilized using sutures to achieve tension-free closure.

In the control group, closure is performed using the conventional Rehrmann buccal advancement flap. After preparation of the extraction socket, a trapezoidal mucoperiosteal flap with vertical releasing incisions is elevated, mobilized using periosteal releasing incisions, and advanced coronally to achieve primary closure of the defect.

The size of the oroantral communication is measured clinically using a calibrated periodontal probe and confirmed with limited-field cone-beam computed tomography (CBCT). Standardized perioperative management is applied in both groups, including socket debridement, smoothing of bony margins, sinus precautions, and scheduled postoperative follow-up.

• Study Type: Interventional
• Enrollment (Actual): 24
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Poland
  • Bytom, Poland
    • University Dental Clinic of the Silesian Medical University in Katowice

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 18 years or older
• Acute oroantral communication diagnosed within 24 hours after extraction of a maxillary posterior tooth
• General health status permitting outpatient dental surgery
• Indication for single-tooth extraction in the posterior maxilla
• Systemic conditions not contraindicating minor oral surgery
• Ability and willingness to attend scheduled follow-up visits
• Provision of written informed consent

Exclusion Criteria:

• Oroantral communication present for more than 24 hours
• Chronic inflammatory disease of the maxillary sinus
• History of head and neck neoplastic disease or its treatment
• Pregnancy
• Systemic diseases preventing outpatient surgical treatment
• Blood disorders or coagulation abnormalities
• Ongoing anticoagulant therapy
• Immunosuppressive therapy
• Age under 18 years
• History of multiple previous surgical procedures in the study area

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Resorbable Collagen Membrane Closure; Participants with acute oroantral communication diagnosed within 24 hours after extraction underwent minimally invasive closure using a resorbable heterogeneous collagen membrane (Creos Xenoprotect). After socket debridement and smoothing of sharp bony margins, the membrane was trimmed and inserted in a submucosal position to fully cover the defect. Limited mucoperiosteal elevation was performed without vertical releasing incisions. The membrane was stabilized with horizontal mattress sutures and allowed to integrate and resorb spontaneously. Standardized postoperative care, antibiotics, and follow-up were provided.	Procedure: Resorbable collagen membrane OAC closure; Minimally invasive closure of acute oroantral communication using a resorbable heterogeneous collagen membrane placed in a submucosal position. After extraction socket debridement and smoothing of sharp bony margins, the membrane was trimmed to overlap the defect and inserted beneath the mucosa to fully cover the communication. Limited mucoperiosteal elevation was performed without vertical releasing incisions. The membrane was stabilized using horizontal mattress sutures to achieve tension-free coverage and was left to integrate and resorb spontaneously. Standardized postoperative antibiotics, sinus precautions, and follow-up visits were applied.; Other Names: Creos Xenoprotect; Collagen membrane closure; Submucosal membrane technique
Active Comparator: Buccal Advancement Flap (Rehrmann); Participants with acute oroantral communication diagnosed within 24 hours after extraction underwent closure using the conventional Rehrmann buccal advancement flap. Following socket debridement and smoothing of bony margins, a trapezoidal full-thickness mucoperiosteal flap with vertical releasing incisions was elevated, mobilized with periosteal releasing incisions, and advanced coronally to achieve tension-free primary closure. Standardized postoperative care, antibiotics, and follow-up identical to the experimental arm were applied.	Procedure: Buccal advancement flap OAC closure; Conventional surgical closure of acute oroantral communication using a coronally advanced buccal mucoperiosteal flap. Following socket debridement and smoothing of bony margins, a trapezoidal full-thickness flap with vertical releasing incisions was elevated. Periosteal releasing incisions were performed to allow tension-free coronal advancement of the flap over the defect. Primary closure was achieved with interrupted sutures. Postoperative management, including antibiotics, sinus precautions, and scheduled follow-up, was standardized across study groups.; Other Names: Rehrmann flap; Rehrmann technique; Buccal advancement flap

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in vestibular depth from baseline to 90 days	The primary outcome was the change in oral vestibular depth at the surgical site, measured in millimeters using a calibrated WHO periodontal probe. Measurements were obtained at baseline (day 0) and during follow-up visits. The endpoint reflects preservation of soft tissue architecture after oroantral communication closure. Greater preservation (smaller reduction from baseline) indicates a more favorable clinical outcome for future prosthetic or implant rehabilitation.	Baseline (day 0) to 90 days postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in keratinized gingiva width	Width of keratinized gingiva at the surgical site measured in millimeters with a calibrated WHO periodontal probe at baseline and follow-up visits. The outcome assesses preservation of keratinized tissue after oroantral communication closure. Greater preservation indicates a more favorable soft tissue result for long-term oral hygiene and prosthetic planning.	Baseline (day 0) to 90 days postoperatively
Change in alveolar socket width	Buccopalatal width of the post-extraction alveolar socket measured clinically and radiographically at predefined time points. This parameter evaluates dimensional stability of the alveolar ridge following closure of oroantral communication. Smaller reduction from baseline indicates better preservation of ridge architecture.	Baseline (day 0) to 90 days postoperatively
Postoperative pain intensity (VAS)	Patient-reported pain assessed using a 100 mm Visual Analogue Scale (VAS), where 0 indicates no pain and 100 indicates worst imaginable pain. Patients marked their pain level at each follow-up visit. Lower scores indicate better postoperative comfort.	Postoperative days 1, 7, and 14
Incidence of postoperative complications	Occurrence of adverse postoperative events including swelling, hematoma, epistaxis, wound dehiscence, persistent oroantral communication, fistula formation, or clinical signs of sinusitis. Events were recorded during scheduled follow-up visits.	Up to 90 days postoperatively

Collaborators and Investigators

• Sponsor: Medical University of Silesia

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2021
• Primary Completion (Actual): December 1, 2025
• Study Completion (Actual): December 1, 2025

Study Registration Dates

• First Submitted: February 27, 2026
• First Submitted That Met QC Criteria: March 12, 2026
• First Posted (Actual): March 17, 2026

Study Record Updates

• Last Update Posted (Actual): March 17, 2026
• Last Update Submitted That Met QC Criteria: March 12, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: oral surgery; oroantral communication; acute OAC; buccal advancement flap; Rehrmann flap; CBCT bone density; vestibular depth preservation
• Additional Relevant MeSH Terms: Mouth Diseases; Stomatognathic Diseases; Pathological Conditions, Anatomical; Fistula; Oral Fistula; Pathological Conditions, Signs and Symptoms; Oroantral Fistula
• Other Study ID Numbers: PCN/0022/KB1/94/20/21

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No