Accuracy of digital surgical guides for dental implants / 대한악안면성형재건외과학회지

Background@#Recently developed imaging techniques, such as cone beam computed tomography (CBCT) and CAD/CAM technology, have facilitated reliable implant planning and implant surgical guide production by 3D printing. This study compared the accuracy of implant-guided surgery using the R2GATE® program with CBCT before and after surgery. @*Patients and methods@#The study included patients who visited the Department of Oral and Maxillofacial Surgery at Chonnam National University Hospital from September 2021 to March 2022. Twenty-four implants were placed in eleven patients. Using R2GATE® Windows (Megagen implant, Daegu, Korea) software, implant placement was planned. The difference was measured by the CBCT before and after surgery. The cervical and apical distance and angular deviation of the implants were measured. Statistical analysis was performed using an independent t-test, Pearson correlation, and multiple regression analyses. @*Results@#The three-dimensional linear distance difference between the planned implant and the placed implant was 0.97 ± 0.37 mm at the cervical and 1.13 ± 0.36 mm at the apical. The difference in angle deviation between the planned implant and the placed implant was 3.42 ± 2.12°. Among the variables affecting the accuracy of implant placement, a statistically significant difference was found when using a tissue-supported implant guide, implant diameter and implant length. @*Conclusion@#Based on these results, using the R2GATE® program is useful to use an implant digital surgical guide, and it will be used in various clinic.

Effect of rhBMP-2 applied with a 3D-printed titanium implant on new bone formation in rabbit calvarium.

OBJECTIVE: This study sought to compare the biocompatibility of a three-dimensional (3D)-printed titanium implant with a conventional machined titanium product, as well as the effect of such implant applied with recombinant human Bone Morphogenetic Protein Type 2 (rhBMP-2) for guided bone regeneration. METHODOLOGY: Disk-shaped titanium specimens fabricated either by the conventional machining technique or by the 3D-printing technique were compared by MC3T3-E1 cells cytotoxicity assay. New bone formation was evaluated using a rapid prototype titanium cap applied to the calvaria of 10 rabbits, which were divided into two groups: one including an atelopeptide collagen plug on one side of the cap (group I) and the other including a plug with rhBMP-2 on the other side (group II). At six and 12 weeks after euthanasia, rabbits calvaria underwent morphometric analysis through radiological and histological examination. RESULTS: Through the cytotoxicity assay, we identified a significantly higher number of MC3T3-E1 cells in the 3D-printed specimen when compared to the machined specimen after 48 hours of culture. Moreover, morphometric analysis indicated significantly greater bone formation at week 12 on the side where rhBMP-2 was applied when evaluating the upper portion immediately below the cap. CONCLUSION: The results suggest that 3D-printed titanium implant applied with rhBMP-2 enables new bone formation.

Risk factors for postoperative infection of odontogenic cysts associated with mandibular third molar / 대한악안면성형재건외과학회지

Background@#Odontogenic cysts associated with lower third molar are common. The prognosis for surgical treatment is relatively good. However, postoperative infection discourages the clinicians. Hence, we would like to investigate the factors associated with infection after surgical treatment of cysts associated with the mandibular third molar. @*Methods@#We retrospectively reviewed the medical and radiographic records of 81 patients who were diagnosed with dentigerous cyst or odontogenic keratocyst and underwent cyst enucleation. The factors affecting postoperative infection were divided into host factor, treatment factor, and cystic lesion factor. To identify the factors associated with postoperative infection, we attempted to find out the variables with significant differences between the groups with and without infection. @*Results@#A total of 81 patients (64 male and 17 female) were enrolled in this study. There was no statistical relationship about the postoperative infection between all variables (gender, smoking, diabetes mellitus, age, bone grafting, related tooth extraction, previous marsupialization or decompression, type of antibiotics, cortical perforation associated with cystic lesion, preoperative infection, preoperative cyst size). @*Conclusions@#The results of this study suggest that it is not necessary to avoid bone grafts that are concerned about postoperative infection.

Diagnosis of Acute Leukemia from Oral Manifestation

Leukemia is a hematological malignant disease with various clinical symptoms. Due to the fatal nature of the disease, early detection is important. Oral manifestations include ulcers and gingival enlargement with bleeding. Moreover, myeloid sarcoma or opportunistic infections may also occur. This report introduces a 31-year-old male presenting with generalized gingival enlargement with bleeding and another 81-year-old female with neoplasm on the left retromolar area. Both were diagnosed as acute monocytic leukemia. These cases implicate that gingival enlargement or mucosal lesion in the oral cavity may represent underlying systemic diseases. Related to this, it has to be reminded that making timely diagnosis and referral according to the clinical findings is crucial.