2.1 General information
This study was retrospective study and was approved by the Medical Ethics Committee of the First Affiliated Hospital of Sun Yat-sen University. Forty patients, 22 males and 18 females, aged from 22 to 75 years, with a mean age of (52.31±16.74) years, who underwent immediate oral implant surgery with dynamic navigation system in the Department of Dentistry of our hospital from 1 January 2021 to 31 January 2024 were enrolled. A total of 62 implants were placed.
Inclusion criteria :(1) Teeth that cannot be retained due to endodontic, periapical or periodontal disease. (2) Cone beam CT (CBCT) showing sufficient bone for implant placement;
Exclusion criteria
(1) There are contraindications for tooth extraction; (2) Severe periodontal and other oral diseases; (3) Severe mouth opening restriction, bruxism, heavy smoking, poor maintenance of oral hygiene, etc.
2.2 Main equipment and materials
Dynamic real-time navigation and planning software (Iris-100, EPED Group, Taiwan), cone CBCT(beam computed tomography) (ICAT, USA), CBCT Design Software (In-vivo 5, Anatomage, USA), GOM Inspect Implant Accuracy Verification System (EPED Group, Taiwan),
Nobel Biocare and Denton implants, Oral Implant (INTRAsurg 300 Plus, KaVo, Germany).
2.3. Clinical Process
(1) Preoperative implant design
The CBCT data were imported into DICOM format to complete the digital jaw reconstruction (Fig.1). The appropriate implant was selected, the implant treatment plan was designed, and the implantation was simulated in the best 3D site (Fig.2). Feature points were selected for intraoperative matching.
(2)The patient is taken into the operating room, sterilized, and a sterile draping is applied. The usual preoperative preparations are made, and the navigation device is positioned. The instruments are connected, and the implant and feature points are aligned. Once the alignment is complete, the navigation system is activated, and the relationship between the implant drill bit and the bone of the socket is displayed on the navigation screen. Then, the surgeon performs the implant placement surgery under the guidance of the real-time navigation system, precisely completing the preparation of the implantation hole and the implantation of the implant (Fig. 3). After implant placement, a healing abutment was placed. If there was insufficient bone around the implant, autogenous bone or bone powder was implanted. The surgeon can observe the dynamic and static views on the display screen and follow the software instructions in real time to adjust the implantation position, angle, and depth to ensure that the implantation results meet the predetermined plan and minimize trauma and postoperative complications, thus completing a truly minimally invasive, precise computer-assisted surgery.
2.4 Key points in the co-ordination of care
2.4.1 Preoperative care
(1) Psychological care
Patients often had anxiety and fear before surgery, were unclear about the implantation and navigation technology, and worried about the operation cost, effect and postoperative pain. The attending physician introduced the operation plan and cost to the patients, and the attending nurses introduced the operation process, the key points of collaboration, the success rate of the operation, and the features and advantages of the navigation system to the patients in detail, thus enabling the patients to have a comprehensive and scientific cognitive implantation surgery, and to pay attention to the preoperative psychological changes and skillfully use psychological communication skills according to the actual situation of different patients. Relieve or alleviate their depression, anxiety, tension and other negative emotions, make patients actively cooperate with treatment and care, and help patients sign the informed consent for surgery.
(2)Patient preparation
On preoperative oral cavity clean and blood tests, including routine blood tests, screening, and clotting time and preoperative infection, etc. A positioning occlusion plate was prepared cooperatively and used as an intraoperative registration stent.The occlusion plate was placed in the mouth, the upper and lower jaws were separated, and CBCT images were taken. After CBCT was completed, the positioning occlusal splints were properly preserved and immersed in 75% alcohol solution for disinfection at 1 hour before operation. The patient's past history and allergy history were inquired in detail, whether there were systemic diseases, and the condition of the patient's mouth and jaw bone were evaluated. Female patients should avoid menstrual period. In patients with preoperative prophylactic use of antibiotics for 1 h.
2.4.2 Preparation of surgical instruments
Surgical instruments, implant surgical tool kits and navigation tool kits for maxillofacial surgery should be prepared strictly in accordance with aseptic technique standards. All items should be disinfected and sterilised prior to use. Note that navigation surgical tools should be disinfected with low-temperature plasma. Prepare first aid equipment and supplies, disinfect with ultraviolet light 1 hour before surgery and wipe all surfaces with disinfectant. Prepare 0.9% saline, 75% ethanol, 0.5% iodopor, sterile gloves, cooling water tube, aspirator, periosteum, bone powder, implant machine and navigator. Check the type, size and number of implants. Due to the complexity of the procedure and the novel navigation technology, the scrub nurses and circulating nurses were all experienced implant nurses who were familiar with the anatomy of the site and experienced in surgical nursing collaboration.
2.4.3 Intraoperative care
(1) Reference plate selection and Navigator calibration
The patient was seated in the chair and asked to gargle with chlorine-containing mouthwash 3 times for 1 minute each time. The chair position and light were adjusted and the dentist assisted in injecting the local anaesthetic. 75% ethanol cotton balls were used for external disinfection, surgical gowns were worn and towels were spread out. This operation takes a long time and uses a lot of instruments and materials. Therefore, it is necessary to set up two sterile tables and place the navigation instruments and implant instruments separately. Adjust the shadowless light to make the surgical field clear, and install the planter and navigator correctly. This surgery using infrared optical positioning technology, the nurses should be prepared to wear special parts needed for navigation guidance and mobile phone reference version, reasonably adjust the navigator and mobile phone reference plate distance and angle, to ensure that the navigator optical tracking device can capture phone bit and the position of patients with jaw bone. The special drilling needle for calibration is installed on the mobile phone and given to the doctor. To calibrate this surgical navigation, the drill should be placed in the spherical groove of the reference plate so that the two fit closely together. The calibration step is carried out in the calibration module of the software to determine the tip of the drilling needle and the axial coordinate system of the mobile phone.
(2) Equipment installation and registration
The appropriate connecting rod and reflective ring should be correctly selected, sterilised and reserved according to the implant area. Calibration according to the operator, the patients wearing preoperative disinfection good positioning bite plate, and compared with the connecting rod and reflection ring assembly. Nurses should assist the dentist in placing the positioning device, which is usually placed in the appropriate position on the other side of the same jaw in the implant area, and ensure that the retention is stable and not easy to move. The mobile phone with the short probe was given to the dentist to help him align the jaw with the 3D virtual image using the registration marks to complete the registration. After the configuration is completed, it is necessary to carefully observe whether the position of the bit displayed by the system is accurate when the bit is placed on the tip to ensure the accuracy of registering.
(3) The implant was placed under the guidance of navigation
The open bite pad was placed in the patient's mouth to avoid opening for too long to cooperate with the surgery. Pass the mobile phone equipped with the positioning drill to the doctor to determine the implantation point, carefully observe the error control icon on the screen of the navigator, and be alert to the alarm of the system. The pioneer drill was transferred to the doctor, and the surgeon was assisted to determine the axial position according to the navigation software instructions. The reaming needles were replaced in time, and further reaming was performed until the depth of the prepared cavities was consistent with the design scheme. During the operation, nurses need to be familiar with the performance of the implant machine and the characteristics of the corresponding implant system, accurately transfer the surgical instruments, timely absorb saliva to ensure the surgical field is clear, correctly adjust the rotation speed and torque of the implant machine，closely observe whether the cooling water is flowing smoothly to prevent bone burns, and closely observe the patient's blood pressure, heart rate, heart rhythm, exhalation, pulse and other vital signs. The type and quantity of implants, bone substitutes and bio-collagen membranes were checked accurately.
2.4.4 Postoperative management
Postoperative CBCT was performed. All patients received routine anti-infective therapy after surgery. Stitches were removed and temporary repair was performed 7 days after surgery, and permanent repair was completed 6 months after surgery.
2.5 Data collection: The preoperative design and postoperative CBCT data were imported into the dental implant dynamic navigation accuracy verification software. The preoperative and postoperative CBCT jaw-level three-dimensional registration was performed by the same clinician to analyse the error between the preoperative virtual implant design and the postoperative implant axial information. The actual implant top, apex, angle deviations were calculated and reported.
2.6 Statistical methods
In this study, SPSS 23.0 statistical software was used to process the data of precision deviation after dynamic real-time navigation guided implant placement. All data included actual implant top, apical, and angular deviation. The measurement data in this study were in accordance with normal distribution, described by Mean ± SD, and the median, extreme value, and interquartile range Q1 and Q3 were recorded at the same time.