Assessment of traumatic mandibular nerve using MR neurography sequence: a preliminary study.

BACKGROUND: Iatrogenic mandibular nerve damage resulting from oral surgeries and dental procedures is painful and a formidable challenge for patients and oral surgeons alike, mainly because the absence of objective and quantitative methods for diagnosing nerve damage renders treatment and compensation ambiguous while often leading to medico-legal disputes. The aim of this study was to examine discriminating factors of traumatic mandibular nerve within a specific magnetic resonance imaging (MRI) protocol and to suggest tangible diagnostic criteria for peripheral trigeminal nerve injury. METHODS: Twenty-six patients with ipsilateral mandibular nerve trauma underwent T2 Flex water, 3D short tau inversion recovery (STIR), and diffusion-weighted imaging (DWI) acquired by periodically rotating overlapping parallel lines with enhanced reconstruction (PROPELLER) pulse sequences; 26 injured nerves were thus compared with contra-lateral healthy nerves at anatomically corresponding sites. T2 Flex apparent signal to noise ratio (FSNR), T2 Flex apparent nerve-muscle contrast to noise ratio (FNMCNR) 3D STIR apparent signal to noise ratio (SSNR), 3D STIR apparent nerve-muscle contrast to noise ratio (SNMCNR), apparent diffusion coefficient (ADC) and area of cross-sectional nerve (Area) were evaluated. RESULTS: Mixed model analysis revealed FSNR and FNMCNR to be the dual discriminators for traumatized mandibular nerve (p < 0.05). Diagnostic performance of both parameters was also determined with area under the receiver operating characteristic curve (AUC for FSNR = 0.712; 95% confidence interval [CI]: 0.5660, 0.8571 / AUC for FNMCNR = 0.7056; 95% confidence interval [CI]: 1.011, 1.112). CONCLUSIONS: An increase in FSNR and FNMCNR within our MRI sequence seems to be accurate indicators of the presence of traumatic nerve. This prospective study may serve as a foundation for sophisticated model diagnosing trigeminal nerve trauma within large patient cohorts.

Considerations for Mandibular Reconstruction in the Pediatric Patient Following Resection of Malignant Tumors.

We recently achieved favorable results in 3 pediatric patients with mandibular osteosarcomas that were treated at our hospital, including with immediate reconstructive surgery performed after tumor resection. Based on a literature review and practical investigation, we discuss the considerations for mandibular reconstruction after malignant lesions are removed from the mandible in children. Mandibular reconstruction for pediatric patients requires an understanding of the changes in bone and soft-tissue architecture due to growth and development at both the donor and recipient sites. Immediate mandibular reconstruction with a free flap can be considered a reasonable option even for young children who require extensive mandibular surgery. However, the variables affecting decisions about treatment planning vary between the different conditions in individual patients, and moreover, these cases are not common in the pediatric population. Therefore, long-term follow-up treatment and further investigations are required for the optimized diagnosis, treatment, and prognosis of pediatric mandibular malignancies.

Is immediate dental implant in fibula free flap beneficial for implant survival and osteoradionecrosis in jaw reconstruction?

OBJECTIVES: This study aimed to compare the risk of osteoradionecrosis and implant survival in oral cancer patients undergoing immediate dental implants during jaw reconstruction, termed "Jaw in a Day" (JIAD), with those receiving no implants or delayed implants (non-JIAD). PATIENTS & METHODS: Clinicopathologic data were collected from prospectively enrolled JIAD patients (n = 10, 29 implants) and retrospectively from non-JIAD patients (n = 117, 86 implants). Survival analyses were performed to assess implant survival and osteoradionecrosis-free survival. RESULTS: Osteoradionecrosis occurred in 0 % of JIAD cases compared to 19.3 % in non-JIAD cases without implants and 71.4 % in non-JIAD cases with delayed implants (p = 0.008). Osteoradionecrosis-free survival was significantly better in the JIAD group than the non-JIAD group (p = 0.0059). Implants in the JIAD group all survived regardless of radiation therapy (29/29, 100 %) and 95.1 % (58/61) of implants survived in delayed implants in non-irradiated fibula without radiotherapy. Meanwhile, only 11 of 25 implants placed in irradiated fibula flaps survived, even when the implants were placed after a median time interval of 624 days after radiotherapy, and none of them were earlier than 360 days. The survival analysis revealed a significant difference (p < 0.0001). CONCLUSION: JIAD appears to offer superior outcomes in terms of implant survival and osteoradionecrosis prevention compared to delayed implant placement. Placing implants in irradiated fibula, even after years, significantly poses high risk of implant failure and osteoradionecrosis. JIAD represents a promising approach for optimal rehabilitation, particularly in oral cancer patients requiring postoperative radiotherapy. Proper positioning and orientation of implants and flaps are crucial for implant survival.

Anatomical basis of the deep circumflex iliac artery flap.

OBJECTIVES: The deep circumflex iliac artery (DCIA) free flap has several advantages for oromandibular reconstruction, such as the large amount of bone available, appropriate vessel diameters for easy vascular anastomosis, an ideal medium for dental implants, and low donor-site morbidity. However, its popularity has declined essentially because of the variable vessel anatomy. The main disadvantage of the DCIA flap is that its dissection is time consuming and requires a greater anatomical knowledge compared with other commonly harvested free flaps. Here, we describe the anatomical variability relevant to the DCIA flap to allow a clear and easy dissection. MATERIALS AND METHODS: Three male and seven female preserved Korean adult cadavers were dissected bilaterally (20 sides). The age at death ranged from 46 to 84 years. Various measurements were made, including the origins of the DCIA and deep circumflex iliac vein (DCIV), lengths of the DCIA and DCIV, and the types of ascending branch of the DCIA. RESULTS: The origin of the DCIA was 5.30 ± 6.22 mm (mean ± SD) superior to the inguinal ligament, and the DCIV was 4.75 ± 3.14 mm medial to the origin of the DCIA. The length of the DCIA from its origin to the level of the anterior superior iliac spine was 59.35 ± 9.06 mm, and the vertical distance between the anterior superior iliac spine and DCIA was 18.50 ± 3.82 mm. With regard to the branching pattern of ascending branch, most cases (n = 18, 90%) exhibited 1 origin and 2 branches, and the remaining 2 cases (10%) had 2 origins and 2 branches. The distance from the DCIA origin to the branch point in cases exhibiting 1 origin and 2 branches was 36.83 ± 16.10 mm. CONCLUSIONS: The anatomical findings presented here regarding anatomical variability relevant to DCIA flap harvesting may facilitate the DCIA flap approach for clinicians.

Better oral hygiene is associated with a reduced risk of osteoporotic fracture: a nationwide cohort study.

Background: The aim of this study was to examine the longitudinal association between oral health parameters and osteoporotic fracture. Methods: The study included participants who received oral health screening by dentists from the National Health Screening cohort database of Korea between 2003 and 2006. The primary outcome was osteoporotic fracture occurrence, which was defined using specific international classification of diseases-10 codes; vertebral fracture (S22.0, S22.1, S32.0, S32.7, T08, M48.4, M48.5, and M49.5), hip fracture (S72.0 and S72.1), distal radius fracture (S52.5 and S52.6), and humerus fracture (S42.2 and S42.3). The presence of periodontitis and various oral health examination findings, such as missing teeth, caries, frequency of tooth brushing, and dental scaling, were analyzed using a Cox proportional hazard model to assess their association with osteoporotic fracture occurrence. Results: The analysis included a total of 194,192 participants, among whom 16,683 (8.59%) developed osteoporotic fracture during a median follow-up of 10.3 years. Poor oral health status, including periodontitis (adjusted hazard ratio [aHR]: 1.09, 95% confidence interval [CI]: 1.01-1.18, p = 0.039), a higher number of missing teeth (≥15; aHR: 1.59, 95% CI: 1.45-1.75, p < 0.001), and dental caries (≥6; aHR: 1.17, 95% CI: 1.02-1.35, p = 0.030), was associated with an increased risk of osteoporotic fracture. On the other hand, better oral hygiene behaviors such as brushing teeth frequently (≥3 times per day; aHR: 0.82, 95% CI: 0.78-0.86, p < 0.001) and having dental scaling within 1 year (aHR: 0.87, 95% CI: 0.84-0.90, p < 0.001) were negatively associated with the occurrence of osteoporotic fracture. Conclusion: The study found that poor oral health, such as periodontitis, missing teeth, and dental caries, was associated with an increased risk of osteoporotic fracture. Conversely, good oral hygiene behaviors like frequent teeth brushing and dental scaling within 1 year were associated with a reduced risk. Further research is needed to confirm this association.

Characteristics of bisphosphonate-related osteonecrosis of the jaw after kidney transplantation.

Renal transplantation is the definitive treatment of chronic renal failure, and osteoporosis in patients after renal transplantation is caused by the use of high-dose corticosteroids, reduced renal function, and the use of immunosuppressant. While bisphosphonates inhibit osteoclastic activities, they are the drug of choice for the treatment and prevention of osteoporosis. Bisphosphonate-related osteonecrosis of the jaw (BRONJ) becomes a problematic issue. There are few reports on BRONJ in patients after renal transplantation, so many oral bisphosphonates commonly prescribed in patients after renal transplantation to prevent osteoporosis have no warning of BRONJ. We analyzed the records of patients with BRONJ from January 2009 to December 2010. Among the patients with BRONJ, we selected patients who underwent transplantation of the kidney. Demographic data, drug-related factors, and clinical characteristics were evaluated using chart review. A total of 128 patients were categorized as having BRONJ, and there were 3 patients with a history of kidney transplantation. The average age was 54.6 years, and 2 victims were men. All patients received oral bisphosphonates for more than 2 years (range, 2-7 y; average, 58.6 mo). All patients had hypertension, diabetes mellitus, history of high-dose corticosteroids, and taking immunosuppressant drugs. Bisphosphonate-related osteonecrosis of the jaw occurred in the maxilla in all patients, which is classified as stage 3 because of the involved sinus. Extraction was the main provoking factor in all patients. In conclusion, even at a relatively young age, BRONJ in the maxilla can be developed by intake of oral bisphosphonate after kidney transplantation. Dental care for patients before and after undergoing renal transplantation should be emphasized to reduce the risk of BRONJ.

Association between oral health and cardiovascular outcomes in patients with hypertension: a nationwide cohort study.

OBJECTIVE: Studies on the association of oral hygiene indicators with cardiovascular disease in hypertensive patients have been lacking. Oral hygiene is directly or indirectly associated with systemic inflammation, one of the essential mechanisms of cardiovascular disease. Therefore, we hypothesized that oral hygiene would be related to the risk of cardiovascular diseases in hypertensive patients. METHODS: We included 52 677 hypertensive participants who completed oral health checkups from the Korean National Health Insurance Service-National Health Screening Cohort between 2003 and 2004. We collected data on periodontitis diagnosis and treatment history, number of teeth loss, number of dental caries, and frequency of tooth brushing from medical records of health claims and oral health examination. The primary outcome was defined as composite outcomes of stroke and myocardial infarction. Follow-up was done until the date of primary outcome, or 31 December 2015. RESULTS: During the 11.26 ±â€Š2.39 years (mean ±â€Šstandard deviation) of the study follow-up, 3292 participants developed primary outcomes [stroke (n = 2430), myocardial infarction (n = 862)]. In multivariable Cox regression analyses, participants with dental caries (≥ 5) were independently associated with occurrence of a primary outcome [adjusted hazard ratio: 1.37; 95% confidence interval (CI):1.10-1.72; P = 0.006]. Frequent tooth brushing (≥ 2 times/day) was significantly related to lower risk of primary outcomes (adjusted hazard ratio: 0.88; 95% CI: 0.81-0.96; P = 0.002). CONCLUSION: Our study demonstrated that multiple dental caries were related to the risk of cardiovascular diseases in hypertensive patients. Better oral hygiene may attenuate the risk of cardiovascular events in hypertensive patients.

Study of Infraorbital Foramen Using 3-Dimensional Facial Bone Computed Tomography Scans.

BACKGROUND: Previous studies of variations of the infraorbital foramen (IOF) demonstrated conflicting results regarding to the side and gender in which specific variations occur. Significant differences in some measurement points between genders have been found, whereas, other studies did not report such differences. The presence of an accessory IOF (AIOF) can result in incomplete anesthesia or treatment failure. Previous studies have demonstrated variable results regarding the prevalence of an AIOF ranging from 16.9% to 47.6%. OBJECTIVES: The purpose of this study was to perform a morphological and morphometric study of the IOF and AIOF based on images of 3-dimensional (3D) facial bone computed tomography (CT) scans. STUDY DESIGN: Retrospective study. METHODS: Identification and analysis of patients who have undergone facial bone 3D CT were performed using Clinical Data Warehouse v 2.5 (CDW, Planit Healthcare, Seoul, Korea). The search term that we used with the CDW for analysis was "facial bone 3D CT."First, the region below the infraorbital rim was examined to determine the presence of the IOF and AIOF. Second, the shape of the IOF was determined and categorized as circular or oval. Third, the vertical (VD) and horizontal (HD) diameters of the IOF were determined. Lastly, the distances between important anatomic landmarks and the IOF were measured. RESULTS: A single IOF with a circular shape was most common. The HD and VD of the IOF were significantly larger in men than in women. The distance between the IOF and the infraorbital margin was similar between men and women. The distances measured from the lateral nasal aperture (LNA) to the IOF and the anterior nasal spine (ANS) to the IOF, at both sides, were significantly shorter in women than in men. The prevalence of the AIOF on the right and left side was 7.3% and 8.9%, respectively. The most commonly observed position of the AIOF was on the inferior medial side of the IOF. LIMITATIONS: This study had an imbalance in the number of male and female patients. CONCLUSIONS: The size of the IOF was larger in men than in women. The distance of the IOF from the infraorbital margin was similar for men and women, whereas, the distances between the IOF and the ANS and the IOF and LNA were shorter in women than in men.

A 5-year retrospective cohort study of denosumab induced medication related osteonecrosis of the jaw in osteoporosis patients.

Denosumab has been suggested as a first-line therapy for osteoporotic patients. However, a standardized protocol for the prevention of denosumab induced medication-related osteonecrosis of the jaw (MRONJ) has not yet been established. The purpose of this study was to report denosumab induced MRONJ cases, and investigate the factors affecting the occurrence of MRONJ in patients who underwent denosumab and invasive dental treatment (especially tooth extraction) between October 2016 and March 2020. Four of the 98 patients developed MRONJ before and after tooth extraction. The participants were divided into two groups: receiving only denosumab (n = 51) and receiving bisphosphonate as first treatment and denosumab as second treatment (n = 47). There was no significant difference between groups in the occurrence of MRONJ and factors affecting MRONJ. Two out of 4 patients developed MRONJ regardless of invasive treatment after denosumab administration and proceeded with extraction; one patient developed MRONJ after denosumab administration and extraction. The other patient underwent a tooth extraction without osteoporosis treatment, and non-identified MRONJ developed after denosumab administration. MRONJ cases reported in this study show that MRONJ can develop as chronic inflammation without invasive dental treatment; therefore, implementing preventive dental treatment before initiating denosumab treatment is necessary to reduce the occurrence of MRONJ.

Comparison of detection performance of soft tissue calcifications using artificial intelligence in panoramic radiography.

Artificial intelligence (AI) is limited to teeth and periodontal disease in the dental field, and is used for diagnosis assistance or data analysis, and there has been no research conducted in actual clinical situations. So, we created an environment similar to actual clinical practice and conducted research by selecting three of the soft tissue diseases (carotid artery calcification, lymph node calcification, and sialolith) that are difficult for general dentists to see. Therefore, in this study, the accuracy and reading time are evaluated using panoramic images and AI. A total of 20,000 panoramic images including three diseases were used to develop and train a fast R-CNN model. To compare the performance of the developed model, two oral and maxillofacial radiologists (OMRs) and two general dentists (GDs) read 352 images, excluding the panoramic images used in development for soft tissue calcification diagnosis. On the first visit, the observers read images without AI; on the second visit, the same observers used AI to read the same image. The diagnostic accuracy and specificity for soft tissue calcification of AI were high from 0.727 to 0.926 and from 0.171 to 1.000, whereas the sensitivity for lymph node calcification and sialolith were low at 0.250 and 0.188, respectively. The reading time of AI increased in the GD group (619 to 1049) and decreased in the OMR group (1347 to 1372). In addition, reading scores increased in both groups (GD from 11.4 to 39.8 and OMR from 3.4 to 10.8). Using AI, although the detection sensitivity of sialolith and lymph node calcification was lower than that of carotid artery calcification, the total reading time of the OMR specialists was reduced and the GDs reading accuracy was improved. The AI used in this study helped to improve the diagnostic accuracy of the GD group, who were not familiar with the soft tissue calcification diagnosis, but more data sets are needed to improve the detection performance of the two diseases with low sensitivity of AI.

Biodegradable poly(lactide-co-glycolide) microspheres encapsulating hydrophobic contrast agents for transarterial chemoembolization.

Transarterial chemoembolization (TACE) is a therapeutic approach to address hepatocellular carcinoma by obstructing the blood supply to the tumor using embolic agents and improving the local delivery of anticancer agents. Size-calibrated polymeric microspheres (MSs) termed drug-eluting beads (DEBs) are the most prevalent solid embolic materials; however, their limitations include insufficient X-ray visibility or biodegradability. In this study, size-controlled polymeric MSs with inherent radiopacity and biodegradability were created, and their embolic effect was assessed. Poly(lactide-co-glycolide) MSs (PLGA MSs) incorporating a hydrophobic X-ray contrast agent and an anticancer drug were produced by the w/o/w emulsion process. Their sizes were exactly calibrated to 71.40 ± 32.18 and 142.66 ± 59.92 µm in diameter, respectively, which were confirmed to have sizes similar to the clinically available DEBs. The iodine content of PLGA MSs was calculated as 144 mgI/g, and the loading quantity of the drug was 1.33%. Manufactured PLGA MSs were gradually degraded for 10 weeks and consistently released the anticancer drug. Following the PLGA MSs injection into the renal artery of New Zealand white rabbit test subjects, their deliverability to the targeted vessel through the microcatheter was confirmed. Injected PLGA MSs were clearly imaged through the real-time X-ray device without blending any contrast agents. The embolic effect of the PLGA MSs was ultimately established by the atrophy of an embolized kidney after 8 weeks. Consequently, the designed PLGA MS is anticipated to be an encouraging prospect to address hepatocellular carcinoma.

Risk Factors of Microscopically Tumor-Free Surgical Margins for Recurrence and Survival of Oral Squamous Cell Carcinoma Patients.

Objectives: The concept of adequate surgical margins remains controversial in oral squamous cell carcinoma (OSCC) surgery. This study aimed to identify surgical margin-related indicators that might impact recurrence and survival of OSCC patients. Materials and Methods: Histopathological examination was performed using hematoxylin-eosin-stained surgical margin tissue sections in 235 OSCC patients. Axin2 and Snail expression at the surgical margin was detected by immunohistochemistry. The impact of the Axin2-Snail cascade on tumorigenesis of the immortalized human oral keratinocyte (IHOK) line was investigated in vivo. Results: The width and dysplasia of surgical margins were not significantly associated with the outcome of OSCC patients. In a multivariate analysis using variable clinicopathologic factors and with Axin2 and Snail expression as cofactors, higher age (hazard ratio [HR]:1.050; P=0.047), Axin2 (HR:6.883; P=0.014), and Snail abundance (HR:5.663; P=0.009) had independent impacts on worsened overall survival. Similarly, lesion site in retromolar trigone (HR:4.077; P=0.010), upper (HR:4.332; P=0.005) and lower gingiva (HR:3.545; P=0.012), presence of extranodal extension (HR:9.967; P<0.001), perineural invasion (HR:3.627; P=0.024), and Snail abundance (HR:3.587; P<0.001) had independent impacts on worsened recurrence-free survival. Furthermore, Axin2 knockdown induced decreased Snail expression and attenuated tumorigenesis in the IHOK line. Conclusion: Histopathological examination of surgical margins may not be reliable to predict OSCC patient outcome. Molecular analysis may provide a more accurate risk assessment of surgical margins in OSCC. In particular, Axin2 and Snail are potential predictive biomarkers for the risk assessment of surgical margins in OSCC.

Charging effect in Au nanoparticle memory device with biomolecule binding mechanism.

Organic memory device having gold nanoparticle (Au NPs) has been introduced in the structure of metal-pentacene-insulator-silicon (MPIS) capacitor device, where the Au NPs layer was formed by a new bonding method. Biomolecule binding mechanism between streptavidin and biotin was used as a strong binding method for the formation of monolayered Au NPs on polymeric dielectric of poly vinyl alcohol (PVA). The self-assembled Au NPs was functioned to show storages of charge in the MPIS device. The binding by streptavidin and biotin was confirmed by AFM and UV-VIS. The UV-VIS absorption of the Au NPs was varied at 515 nm and 525 nm depending on the coating of streptavidin. The AFM image showed no formation of multi-stacked layers of the streptavidin-capped Au NPs on biotin-NHS layer. Capacitance-voltage (C-V) performance of the memory device was measured to investigate the charging effect from Au NPs. In addition, charge retention by the Au NPs storage was tested to show 10,000 s in the C-V curve.

Treatment of posttraumatic fingertip pain using a great toe pulp graft.

Complications of fingertip injury include pain, hyper- or dyssensitivity, cold intolerance, and fingertip atrophy. Especially in cases of soft-tissue defect or atrophy which result from crushing injury, fingertip pain often occurs when a finger touches the objects. To overcome this problem, several techniques including local flaps or free flaps were suggested. But these methods require intricate and multistaged procedures.Twelve patients who had fingertip pain with pulp atrophy were treated with pulp graft between March 2004 and March 2006. Under the local anesthesia, we made a fish-mouth incision at the most prominent portion of fingertip and elevated volar flaps. Composite tissue was harvested from the lateral aspect of great toe, and inserted between the previously elevated volar flaps. The harvested composite pulp tissue contained about 3- to 5-mm thick fat layer. Moisture dressing was performed. The visual analogue scale (VAS) was used to evaluate the degree of pain postoperatively. The follow-up period was in the range between the 12 and 24 months (average, 19 months). Pre- and postoperative differences in VAS scores were analyzed for statistical significance, using the Wilcoxon rank sum test. In addition, patients were asked about their level of satisfaction with the procedure. To evaluate the postoperative sensation of the graft, we performed the Semmes-Weinstein monofilament test, and static and dynamic 2-point discrimination test at 1 year postoperatively.The size of the graft was ranged from 276 mm (12 × 23 mm) to 750 mm (25 × 30 mm). At final follow-up review, 5 patients were very satisfied and 7 were satisfied. Atrophy of the fingertip was also improved. Fingertip pain reduced from 8.5 preoperative to 3.1 postoperative on VAS. These improvements were statistically significant. Semmes-Weinstein monofilament test was green (∼2.83) in 9 patients (75%) and blue (3.22-3.61) in 3 of 12 patients (25%). Static and dynamic 2-point discrimination test results came out as 6 and 5 mm, respectively.Composite graft applied to the fingertip is a simple technique, and gives few complications. This procedure can be performed under local anesthesia and gives a fairly high degree of satisfaction to patients. We believe this method is useful for treating fingertip pain with atrophy of pulp.

A piezoelectric motor-based microactuator-generated distractor for continuous jaw bone distraction.

Distraction osteogenesis is widely applied to correct oral and maxillofacial deformities, and intermittent distraction protocols have been used in various clinical applications. There are many challenges for continuous distraction of the jaw bone such as when using hydraulic motors and motor-driven plates. The size of the motor is critical to the ability to miniaturize the complete distractor system, and the importance of size makes it difficult to extrapolate the results of animal models to the clinical situation. This study developed a microactuator-generated distractor (MAGD) for continuous jaw bone distraction. The MAGD system consists of control software based on Microsoft Windows and a Squiggle piezoelectric motor. The system allows various intermittent and continuous distraction protocols to be simply selected using the control software. The maximum force of the laboratory-scale MAGD is 3 N, and the device is ready for adoption in small-animal distraction models such as the rat and mouse. The MAGD needs further refinement before it can be applied to humans, but a fully implanted MAGD system will reduce soft-tissue complications resulting from exposure of the extraoral component. Moreover, the MAGD will support the patient's social activities and require only minimal cooperation from the patient.

Appropriate follow-up period for odontogenic keratocyst: a retrospective study.

PURPOSE: The aim of this study was to conduct epidemiologic investigations on the pattern of the lesion and differences between treatment modalities in terms of recurrence by reviewing follow-up records to form a basis for planning patient follow-up visits. MATERIALS AND METHODS: In this retrospective, single-center cohort study, 266 patients diagnosed with odontogenic keratocyst between 1993 and 2013 were included. Medical records and radiographic images were analyzed for age distribution, occurrence site and size, treatment modalities, and recurrence. RESULTS: The average age at first diagnosis was 33.1 years, and the male to female ratio was 1.33:1.00. The highest rate of incidence was in the third decade followed by the fourth, second, and fifth decades. The incidence in the maxilla was 34%, and 66% in the mandible. Mandibular ramus was most commonly involved. Lesions between 3 and 6 crowns were the most common, and the rate of recurrence increased with size. Enucleation after decompression had higher rate of recurrence (35.8%) than enucleation (27.1%), but there was no statistical significance. CONCLUSION: The recurrence of odontogenic kerotocyst (OKC) was significantly associated with large size, multilocular form, and surgical procedure. A 10-year follow-up period is recommended to determine any recurrence of OKC.

Primary malignant mucosal melanoma of the maxillofacial area.

OBJECTIVES: We aimed to collect and report data from all patients who have been diagnosed with mucosal malignant melanoma to obtain the epidemiology and principles of current treatments. MATERIALS AND METHODS: Between January 2008 and December 2018, 20 patients underwent surgery or follow-up observations at Yonsei University Dental Hospital. The patients' clinical information was reviewed retrospectively. RESULTS: Seventeen of 20 patients had undergone definitive surgery, while only 6 patients received adjuvant radiotherapy or systemic therapy. Eight of 20 patients, including those that had recurrent lesions, were provided immunotherapy. The 3-year survival for all stages was 50%, with a local recurrence rate of 75% and a metastasis rate of 65%. CONCLUSION: The overall survival of patients receiving surgical treatment was longer than that of patients who did not undergo surgical resection. Eight of 20 patients received immunotherapy as the first-line regimen at our clinic, and those patients exhibited longer overall survival compared to patients in reported keynote studies.

Carbon-ion radiotherapy in osteosarcoma of the mandible: a case report.

Carbon-ion radiotherapy (CIRT) is on the rise as a treatment choice for malignant tumor. Compared to conventional radiotherapy, particle beams have different physical and biological properties. Particle beam provides a low entry dose, deposits most of the energy at the endpoint of the flight path, and forms an asymptotic dose peak (the "Bragg peak"). Compared to protons, carbon with its larger mass decreases beam scattering, resulting in a sharper dose distribution border. We report a 50-year-old male who underwent CIRT without surgical resection on osteosarcoma of the mandible. After CIRT, the patient's pain was gone, and the malignant mass remained stable with accompanying necrosis. Nine months later, however, magnetic resonance imaging demonstrated progression of the left mandibular osteosarcoma with pulmonary metastases. After multidisciplinary discussion, concurrent chemoradiotherapy was conducted. While necrotic bone segments came out of the mandible during subsequent periodic outpatient visits, the tumor itself was stable. Thirty months after his first visit and diagnosis, the patient is waiting for chemotherapy. Although CIRT is superior in treating radioresistant hypoxic disease, CIRT is in its infancy, so care must be taken for its indications and complications.

In Vivo Study for Clinical Application of Dental Stem Cell Therapy Incorporated with Dental Titanium Implants.

The aim of this study was to investigate the behavior of dental-derived human mesenchymal stem cells (d-hMSCs) in response to differently surface-treated implants and to evaluate the effect of d-hMSCs on local osteogenesis around an implant in vivo. d-hMSCs derived from alveolar bone were established and cultured on machined, sandblasted and acid-etched (SLA)-treated titanium discs with and without osteogenic induction medium. Their morphological and osteogenic potential was assessed by scanning electron microscopy (SEM) and real-time polymerase chain reaction (RT-PCR) via mixing of 5 × 106 of d-hMSCs with 1 mL of Metrigel and 20 µL of gel-cell mixture, which was dispensed into the defect followed by the placement of customized mini-implants (machined, SLA-treated implants) in New Zealand white rabbits. Following healing periods of 2 weeks and 12 weeks, the obtained samples in each group were analyzed radiographically, histomorphometrically and immunohistochemically. The quantitative change in osteogenic differentiation of d-hMSCs was identified according to the type of surface treatment. Radiographic analysis revealed that an increase in new bone formation was statistically significant in the d-hMSCs group. Histomorphometric analysis was in accordance with radiographic analysis, showing the significantly increased new bone formation in the d-hMSCs group regardless of time of sacrifice. Human nuclei A was identified near the area where d-hMSCs were implanted but the level of expression was found to be decreased as time passed. Within the limitations of the present study, in this animal model, the transplantation of d-hMSCs enhanced the new bone formation around an implant and the survival and function of the stem cells was experimentally proven up to 12 weeks post-sacrifice.