Buccal Periosteal Inversion Flap vs Buccal Advancement Flap for Acute Oro-Antral Communication Closure

An OAC is a pathological communication between the oral cavity and the maxillary sinus and occurs most commonly following extraction of posterior maxillary teeth. Surgical closure is indicated to reduce the risk of maxillary sinusitis.

The Buccal Advancement Flap (BAF) is an established technique for primary closure of acute OACs. However, advancement of the buccal soft tissue results often in a reduction of keratinized gingival width and flattening of the oral vestibule, which may negatively affect subsequent prosthetic or implant treatment.

The Buccal Periosteal Inversion Flap (BUPI) is an alternative technique in which the periosteal layer of a buccal mucoperiosteal flap is separated from the overlying mucosa and inverted to cover the OAC. The overlying mucosa can therefore remain largely in its original position.

The study will prospectively compare both surgical techniques in adult participants presenting with an acute OAC following tooth extraction in the posterior maxilla.

After confirmation of eligibility and written informed constent, participants will undergo a baseline intraoral scan of the relevant quadrant and Periodontal Screening and Recording (PSR) of the relevant sextant. Participants will subsequently be randomized in a 1:1 ratio to BUPI or BAF using the Medical University of Graz randomization system.

The primary endpoint is the change in keratinized gingival width between baseline and three months after surgery. Keratinized gingival width will be measured between the mucogingival junction and the midpoint of the alveolar ridge using digital intraoral scans obtained with a 3Shape TRIOS 6 intraoral scanner. Measurements will be performed using 3D Slicer software.

Participants will document postoperative pain, swelling, and bleeding using a visual analog scale ranging from 0 to 10 on the day of surgery and for the subsequent seven postoperative days.

Clinical follow-up examinations will be performed after 14 days, one month, and three months.

• Buccal Periosteal Inversion Flap (Procedure), also known as BUPI, Inverted Periosteal Flap, Buccal Periosteal Flap: Following elevation of a trapezoidal buccal mucoperiosteal flap, the periosteum is dissected from the overlying buccal mucosa from apical to coronal. The mobilized periosteal layer is inverted over the oro-antral communication and sutured to the palatal soft tissue to achieve tension-free closure, while the overlying buccal mucosa is largely maintained in its original position.
• Buccal Advancement Flap (Procedure), also known as BAF, Rehrmann Flap, Rehrmann Plastic: Following elevation of a trapezoidal buccal mucoperiosteal flap, the periosteum is incised to allow mobilization of the flap. The entire mucoperiosteal flap is advanced over the oro-antral communication to the palatal soft tissue to achieve tension-free primary closure.

Primary outcomes

• Change in Width of Keratinized Gingiva [Baseline to 3 months after surgery]: Change in keratinized gingival width in millimeters between the preoperative baseline assessment and the three-month postoperative assessment. Keratinized gingival width will be measured between the mucogingival junction and the midpoint of the alveolar ridge using digital intraoral scans obtained with a 3Shape TRIOS 6 intraoral scanner and analyzed using 3D Slicer software.

Secondary outcomes

• Successful Closure of the Oro-Antral Communication [14 days after surgery]: Clinical success will be defined as complete closure of the oro-antral communication without persistent communication between the oral cavity and maxillary sinus. The proporiton of successfully closed oro-antral communications will be calculated for each study group.
• Postoperative Pain [Day 0 through postoperative day 7]: Participants will record their daily maximum postoperative pain once daily in the afternoon using a visual analog scale from 0 to 10, where 0 represents no pain and 10 represents very severe pain.
• Postoperative Swelling [Day 0 through postoperative day 7]: Participants will record their daily maximum postoperative swelling once daily in the afternoon using a visual analog scale from 0 to 10, where 0 represents no swelling and 10 represents very severe swelling.
• Postoperative bleeding [Day 0 through postoperative day 7]: Participants will record their daily maximum postoperative bleeding once daily in the afternoon using a visual analog scale from 0 to 10, where 0 represents no postoperative bleeding and 10 represents very severe postoperative bleeding.
• Wound dehiscence [14 days after surgery]: Presence or absence of postopertative separation of the sutured buccal and palatal soft tissues will be clinically assessed. If wound dehiscence is present, its dimensions will additionally be quantified using the intraoral scan.
• Recurrence or Persistence of Oro-Antral Communication [Up to 3 months after surgery]: Occurence of a persistent or recurrent communication between the oral cavity and maxillary sinus during follow-up will be recorded.
• Postoperative Sinusitis or Infection [14 days after surgery]: Occurrence of clinically diagnosed postoperative maxillary sinusitis or local infection at the follow-up examination after 14 days will be recorded. Clinical signs and symptoms may include facial pain, pressure sensation, purulent nasal discharge, intraoral purulent drainage, fever, or other clinically relevant signs of infection.
• Reoperation rate [14 days after surgery]: Percentage of participants in each study group requiring surgical revision because of insufficient closure of the oro-antral communication.
• Operative time [Intraoperatively on Day 0]: Duration of the surgical procedure measured from the first surgical incision to completion of the final suture, recorded in minutes and seconds.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Age ≥ 18 years
* Acute Oro-Antral Communication following extraction of posterior maxillary teeth (premolars and molars) within the last 24 hours
* Good general health
* Willingness to attend all scheduled followu-up examinations

Exclusion Criteria:

* Age < 18 years
* Acute inflammation or maxillary sinusitis
* Absence of nasal drainage during maxillary sinus irrigation
* Previous surgeries in the study area resulting in scarring
* Systemic diseases that could impair wound healing (e.g. uncontrolled diabetes mellitus)
* Immunosuppression
* Diagnosed or previously treated neoplasms
* Bisphosphonate or antiresorptive therapy
* Pregnancy or breastfeeding
* Allergy to dexibuprofen
* Nicotine consumption ≥10 cigarettes/day
* Inability to give informed constent

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• Barbara Kirnbauer, PD DDr., Principal investigator, Medical University of Graz
• Norbert Jakse, Prof. DDr., Study chair, Medical University of Graz