Journal of Orthodontics & Endodontics

Description

A viable alternative to conventional powered instruments for orthognathic surgery has emerged in the form of an ultrasonic bone cutting device that uses the selective cutting of bone by high-frequency vibration of a metallic tip. Although it has been reported that surgical time is longer when using an ultrasonic bone cutting device than when using conventional powered instruments, the advantages of using an ultrasonic bone cutting device include minimal risk of soft tissue damage, excellent visibility within the surgical field due to minimal bleeding and cavitation effect, precision in bone cutting due to limited vibration amplitude and specific design of the ultrasonic cutting tips, and low acoustic and vibrational impact. Additionally, ultrasonic bone cutting tips that are suitable for orthognathic surgery have been developed. In May 2018, the serrated aggressive knife tip of our hospital's Sonopet ultrasonic curettage device received approval in Japan.

Osteotomies in Orthognathic Medical Procedure

The purpose of this study was to compare the efficacy of ultrasonic surgery with the Sonopet ultrasonic curettage device's serrated aggressive knife tip in a combined surgery of Le Fort I osteotomy and Bilateral Sagittal Split Osteotomies (BSSO) to conventional powered instrument surgery. From April 2015 to March 2020, 146 patients with dentofacial deformities underwent a combination of Le Fort I osteotomy and BSSO surgery in our clinical department. Since July 2018, all osteotomies in orthognathic medical procedure has been performed with a serrated forceful blade tip of a ultrasonic curettage gadget (Sonopet UST-2001, Stryker, USA) rather than the controlled instruments, for example, a pivoting bar or saws, so the subjects were isolated into two gatherings as per the date of a medical procedure. All patients (26 males and 62 females) who underwent the procedure from April 2015 to June 2018 were included in the powered instruments group, and all patients (22 males and 36 females) who underwent the procedure from July 2018 to March 2020 were included in the ultrasonic bone cutting device group. At surgery, the average age was 24 (range: Between the ages of 15 and 47, and between the ages of 24 (range: 16–52 years) in the group working on ultrasonic bone cutting devices. There were no cases of multi-piece Le Fort I osteotomy included in the surgeries, which were carried out by multiple surgeons and a skilled surgeon. All subjects received orthodontic treatment before and after surgery, and 800 milliliters of autologous blood were collected and stored prior to surgery. This study was directed with the endorsement of the Niigata College institutional Morals Board. An ultrasonic handpiece and a base control module (UST-2001) make up the Sonopet ultrasonic curettage apparatus. The serrated aggressive knife tip has serrations on both sides and at the tip, making it 12.4 mm long and 0.8 mm thick. With maximum longitudinal amplitude of 0.3 mm, this tip connected to a universal angle handpiece oscillates nonrotatively up to 25,000 times per second. The authors chose an amplitude of 60–70 percent, which is suitable for bone cutting, despite the fact that a setting of 30–100% is available. A white irrigation sleeve surrounding the handpiece channels room-temperature normal saline to the blade for cooling, but this tip does not provide suction. To reduce the amount of heat generated by the tip during orthognathic surgery, we reduce the length of the white irrigation sleeve by one step and set the saline irrigation flow rate to 25–30 ml/min. Standard procedures from the literature were used to perform the Le Fort I osteotomy and BSSO. From the right to the left premolar, the incision for the Le Fort I horizontal osteotomy was made. A U-shaped osteotome was used to separate the nasal septum from the maxilla, and a straight bone cut was made at the lateral maxillary buttress with directions to the ipsilateral piriform rim and the pterygomaxillary junction.

Titanium Miniplates and Screws were Used to Fix the Bone Fragments

The bone was cut vertically along the buccal cortical bone to the inferior border of the mandible and continued anteriorly down the external oblique ridge to the level of the second molar. After that, an Obwegeser osteotome, bone separator, and spatula were used to complete the osteotomy. After that, the mandible was moved into the desired position, and titanium miniplates and screws were used to fix the bone fragments. Le Fort I osteotomy was performed with a reciprocating saw in the powered instruments group, and BSSO was performed with rotating bars like a round bur and a Lindemann bur. In contrast, all osteotomies and bone removal of the maxilla and mandible were performed with the serrated aggressive knife tip of the Sonopet ultrasonic curettage device in the ultrasonic bone cutting device group. The horizontal bone cutting of the maxilla in a Le Fort I osteotomy was done by moving the cutting edge on the side of the blade forward and backward in a continuous sweep. The bone around the descending palatal artery and the pterygoid process area was removed by pressing the tip of the blade and moving it left and right. In BSSO, the cutting edge on the side of the blade was used to cut cortical bone. However, when the inferior alveolar neurovascular bundle is attached to or included in the proximal bone fragment, the tip of the blade is used to separate the neurovascular bundle from the proximal bone fragment. In both groups, the surgical time from the beginning of the incision to the end of the suture was measured. The intraoperative bleeding volume was calculated by subtracting the amount of saline used from the amount of suction and the blood weight of the gauze used. The leverage technique with Tessier's spreaders was used to break the maxilla down, and Rowe's maxillary disimpaction forceps were used to fully mobilize the maxilla. Four resorbable fixation devices were used to stabilize the osteotomy site's mobility after the bone fragment was moved into the expected position. After that, the external oblique line was cut for the BSSO incision, and the subperiosteum was dissected as usual. A bone cut was made through the cortical bone and into the cancellous bone, and a channel retractor was inserted along the medial aspect of the ramus.