The aim of this prospective case series is to present clinical results with cystostomy, decompression and final enucleation of odontogenic cysts using a decompression device fabricated with a full digital workflow and delivered on the day of cystostomy. The secondary purpose of our study is to present the volumetric changes of the odontogenic cysts treated by decompression.

Cystostomy and decompression Patients rinse with 0.2% chlorhexidine solution for 1 min before surgery. Under local anesthesia, an envelope flap from marginal incision is elevated and teeth deemed for extraction are removed in an atraumatic manner. In those cases where the cyst may not be accessed from the sockets of the teeth removed osteotomies are carried out by round burs using a surgical handpiece (SURGmatic S11 L Pro , Kavo Dental, Brea, California, United States) and motor (MASTERsur LUX, Kavo Dental, Brea, California, United States) to create a bony window. A histological sample is collected from the cyst lining to confirm the initial diagnosis of odontogenic cyst. Wound margins are stabilized using single interrupted sutures. The decompression appliance is delivered in the same sitting. Patients are instructed on how to wear and clean their decompression device. Antibiotics (1 g amoxicillin-clavulanate twice a day for 5 days or, in case of side effects or known allergy to penicillin, 300 mg clindamycin 4 times a day for 4 days), non-steroid anti-inflammatory drugs (50 mg diclofenac 3 times a day for 3 days), and chlorhexidine mouthwash (twice a day for 21 days from the first day after surgery) are prescribed. Sutures are removed after 7 days

Postoperative imaging Postoperative CBCT examination is performed six months into the decompression period using the same scanning conditions as those used for the preoperative CBCT scan.

Data acquisition Pre- and postoperative CBCT reconstructions are registered by landmark registration using the 3DSlicer 4.10.2 (The Brigham and Women's Hospital, Inc., Boston, MA, USA) software. The volume of the odontogenic cysts before (Preoperative Volume) and following (Postoperative Volume) decompression are assessed by manual segmentation using the segment editor and segment statistics plug-in. Volume Reduction is calculated by subtracting the Postoperative Volume from the Preoperative Volume. Percentage of Volume Reduction is calculated as follows: Volume Reduction/Preoperative Volume X 100.

Decompression Decompression is maintained until the cyst reduces in volume to an extent, that enucleation may be performed with minimal risk of complications (damage to the anatomical landmarks blood vessels, nerves, roots of neighboring teeth, nasal cavity, maxillary sinuses). During the decompression period patients are recalled for clinical examination and radiographic control (panoramic radiographs) monthly.

Enucleation Following decompression enucleation of the remaining cyst is carried out under local anaesthesia.

Patients are recalled for clinical examination and radiographic control (panoramic radiographs) a year after enucleation to determine whether recurrence of the odontogenic cyst occurs or not.

Inclusion Criteria:

• Patients of the Department of Community Dentistry, Semmelweis University, presenting with odontogenic cysts of the jaws that involved anatomical landmarks were included in the study.

Exclusion Criteria:

• History of tumors or irradiation therapy in the head and neck region,
• History of uncontrolled medical or psychiatric disorders,
• Unwillingness to return for follow-up appointments.