Abstract
An antral pseudocyst on the maxillary sinus has previously been a contraindication for sinus augmentation. The authors report the case of a patient with an antral pseudocyst (16.7 mm × 27.6 mm) in his left sinus, who was referred for dental implant treatment. The surgical plan was to perform the sinus augmentation after removing the cyst whilest simultaneously placing implants. During the operation the cyst could not be found in the left sinus. The sinus augmentation was carried out successfully without sinus membrane perforation and the implants were placed according to plan. Three mouths later, the cyst was still present and good osseointegration of the implants was achieved. After the implants had been in place for a year, a CT scan showed that the cyst had decreased in size. The authors conclude that it is may not be necessary to remove a sinus cyst before sinus augmentation or during the sinus augmentation operation if the patient does not have any symptoms and the cyst is not large. In cases with large lesions or an unclear diagnosis, further evaluation is needed before surgical intervention.
The use of dental implants has gained popularity for treating edentulism, but in some patients jaw atrophy leaves insufficient bone for the placement of dental implants. The placement of dental implants in patients who are edentulous in the posterior maxilla can present difficulties because of a deficient posterior alveolar ridge and increased pneumatization of the maxillary sinus, resulting in a minimal hard tissue bed. The sinus lift procedure was developed to treat these patients. Maxillary sinus floor augmentation techniques are frequently used to increase bone volume in the posterior edentulous maxilla to enable placement and integration of titanium implants . The lateral window approach to sinus augmentation aims to increase bone height and volume inferior to the maxillary sinus membrane to enable subsequent placement of dental implants. This is one of the most predictable regenerative surgical procedures performed in guided bone augmentation surgery and implant survival is highly successful .
According to Z iccardi and B etts , the presence of maxillary cysts is an absolute contraindication for sinus grafting. Maxillary sinus cysts are a group of lesions in which the nomenclature and pathogenesis have been controversial. On rare occasions, the cyst may become infected. Such an infection may cause one or more symptoms . Consequently maxillary sinus antral pseudocysts have been considered a contraindication for sinus augmentation.
This report presents the surgical procedure and outcome of dental implant placement in a patient who had sinus augmentation in the presence of a sinus antral pseudocyst.
Case report
A 45-year-old patient who required implants due to missing upper molars on both sides was referred to the authors’ clinic. He received a course of periodontal treatment due to periodontal disease.
A complete dental examination, which included panoramic and cone beam computed tomography (CT) scans (dental) was performed to help determine the available maxillary alveolar bone height. The crestal bone height between the sinus floor and the alveolar ridge of the posterior maxilla was only 5 mm on both sides. There was a cyst (16.7 mm × 27.6 mm) in the left sinus ( Fig. 1 ); the right sinus was normal. The panoramic reformatted images ( Fig. 1 ) clearly showed the sinus cyst was firmly attached to the sinus floor and the maxillary alveolus height was only about 5 mm. As the patient did not have any symptoms, the otolaryngologist suggested no treatment for the cyst before the operation. The authors decided to treat the sinus cyst during the sinus augmentation operation.
Surgical procedure
The surgery was performed under local anaesthesia and a modified Caldwell-Luc approach was used. After the lateral maxillary wall was exposed, a round bur was used in a low-speed, high-torque straight headpiece at 2000 rpm with copious sterile saline irrigation to create a hole in the lateral wall of the left maxillary sinus. As no cyst liquid leaked out, a 20 ml injector was used to suck the cyst liquid out from a different direction, but it failed to obtain anything in the left sinus. A Piezotome (Acteon, France) TM ultrasonic osteotomy was carried out to create an oval-shaped outline in the lateral wall of the maxillary sinus. After removing the oval-shaped bone from the lateral wall of the maxillary sinus, the authors found the sinus membrane was not perforated, that it vibrated with the patient’s breathing and that it was thicker than normal sinus membrane. The sinus membrane was lifted 7 mm without perforation. Once the implant sites had been prepared, a bovine allograft (BIO-OSS Geistlich, Wolhusen, Switzerland) bio-oss was ‘injected’ into the maxillary sinus and packed against the intact medial wall. After this, the medial portion of the sinus was grafted with two integral cylindrical dental implants (Straumann standard implants sand-blasted, large grit, acid-etched [SLA] 10 mm, regular neck [RN] 4.8 mm, Straumann AG, Switzerland) placed in the augmented sinus. Both implants were placed stably with regards to future restorative treatment. A Bio-Gide (Geistlich Pharma AG, Switzerland) was used to cover the window in the wall of the maxillary sinus and then a mucoperiosteal flap was sutured.
The patient had no symptoms after surgery, other than minor swelling. Three months later, before the second operation was performed, a cone beam CT scan (dental) was carried out. The scan showed that the implants were placed correctly in the augmented sinuses, osseointegration was achieved and the cyst was still there ( Fig. 2 ). The screw-retained provisional restorations were inserted on both sides and the implants were functionally loaded.
