Ultrasound-guided intraoral botulinum toxin injection into the lateral pterygoid muscle for chronic temporomandibular joint dislocation.

Objectives: Botulinum toxin type A (BTX), a powerful neurotoxin, can be an effective treatment choice for diverse muscular disorders and can reduce abnormal muscle activities. Abnormal movements of the mandible can be caused by involuntary and uncontrolled contractions of the lateral pterygoid muscle (LP) in various pathological situations. Previous reports have shown that BTX can reduce abnormal contractions of the LP. However, needle placement into the LP for BTX injection requires skill, experience, and sufficient anatomical knowledge. To place the needle precisely into the LP, ultrasonography (USG) can be used as an effective needle-guidance modality. USG is a non-invasive imaging modality able to create real-time images without any potential risks, including radiation exposure. Patients and. Methods: The patients who had been performed USG-guided BTX injection into the LP using an intraoral approach were included in this study with a literature review and case presentations. Using the USG, four patients received BTX injections to treat recurrent temporomandibular dislocation and oromandibular dystonia resulting from involuntary LP activity. Result: Involuntary movements of the mandible were improved successfully in all patients, and showed satisfactory results without significant complication. Conclusion: The intraoral approach could prevent potential complications during needle placement. USG-guided BTX injection is an effective, convenient, and safe method that provides real-time imaging without unnecessary pain to the patient.

Differential effect of cancer-associated fibroblast-derived extracellular vesicles on cisplatin resistance in oral squamous cell carcinoma via miR-876-3p.

Rationale: Platinum-based chemotherapy is commonly used for treating solid tumors, but drug resistance often limits its effectiveness. Cancer-associated fibroblast (CAF)-derived extracellular vesicle (EV), which carry various miRNAs, have been implicated in chemotherapy resistance. However, the molecular mechanism through which CAFs modulate cisplatin resistance in oral squamous cell carcinoma (OSCC) is not well understood. We employed two distinct primary CAF types with differential impacts on cancer progression: CAF-P, representing a more aggressive cancer-promoting category, and CAF-D, characterized by properties that moderately delay cancer progression. Consequently, we sought to investigate whether the two CAF types differentially affect cisplatin sensitivity and the underlying molecular mechanism. Methods: The secretion profile was examined by utilizing an antibody microarray with conditioned medium obtained from the co-culture of OSCC cells and two types of primary CAFs. The effect of CAF-dependent factors on cisplatin resistance was investigated by utilizing conditioned media (CM) and extracellular vesicle (EVs) derived from CAFs. The impacts of candidate genes were confirmed using gain- and loss-of-function analyses in spheroids and organoids, and a mouse xenograft. Lastly, we compared the expression pattern of the candidate genes in tissues from OSCC patients exhibiting different responses to cisplatin. Results: When OSCC cells were cultured with conditioned media (CM) from the two different CAF groups, cisplatin resistance increased only under CAF-P CM. OSCC cells specifically expressed insulin-like growth factor binding protein 3 (IGFBP3) after co-culture with CAF-D. Meanwhile, IGFBP3-knockdown OSCC cells acquired cisplatin resistance in CAF-D CM. IGFBP3 expression was promoted by GATA-binding protein 1 (GATA1), a transcription factor targeted by miR-876-3p, which was enriched only in CAF-P-derived EV. Treatment with CAF-P EV carrying miR-876-3p antagomir decreased cisplatin resistance compared to control miRNA-carrying CAF-P EV. On comparing the staining intensity between cisplatin-sensitive and -insensitive tissues from OSCC patients, there was a positive correlation between IGFBP3 and GATA1 expression and cisplatin sensitivity in OSCC tissues from patients. Conclusion: These results provide insights for overcoming cisplatin resistance, especially concerning EVs within the tumor microenvironment. Furthermore, it is anticipated that the expression levels of GATA1 and miR-876-3p, along with IGFBP3, could aid in the prediction of cisplatin resistance.

3D simulation of interosseous interference in sagittal split ramus osteotomy for mandibular asymmetry.

BACKGROUND: The purpose of this study was to evaluate the pattern of predicted interosseous interference and to determine the influencing factor to volume of bony interference using a computer-assisted simulation system. This retrospective study recruited 116 patients with mandibular prognathism who had undergone sagittal split ramus osteotomy (SSRO) with or without maxillary osteotomy. The patients were divided into 3 groups according to the amount of menton (Me) deviation: less than 2 mm (Group 1), 2-4 mm (Group 2), and more than 4 mm (Group 3). Changes in the distal segments following BSSRO and the volume of the interosseous interference between the proximal and distal segments were simulated after matching preoperative occlusion and postoperative expected occlusion with the cone-beam computed tomography data. Ramal inclinations and other skeletal measurements were analyzed before surgery, immediately after surgery, and at least 6 months after surgery. RESULTS: The anticipated interosseous interference was more frequently noted on the contralateral side of chin deviation (long side) than the deviated site (short side) in Groups 2 and 3. More interference volume was predicted at the long side (186 ± 343.9 mm3) rather than the short side (54.4 ± 124.4 mm3) in Group 3 (p = 0.033). The bilateral difference in the volume of the interosseous interference of the osteotomized mandible was significantly correlated with the Me deviation (r = - 0.257, p = 0.009) and bilateral ramal inclination (r = 0.361, p < 0.001). The predictor variable that affected the volume of the osseous interference at each side was the amount of Me deviation (p = 0.010). CONCLUSION: By using the 3D simulation system, the potential site of bony collision could be visualized and successfully reduced intraoperatively. Since the osseous interference can be existed on any side, unilaterally or bilaterally, 3D surgical simulation is necessary before surgery to predict the osseous interference and improve the ramal inclination.

Skeletal structure of asymmetric mandibular prognathism and retrognathism.

BACKGROUND: This study aimed to compare the skeletal structures between mandibular prognathism and retrognathism among patients with facial asymmetry. RESULTS: Patients who had mandibular asymmetry with retrognathism (Group A) in The Netherlands were compared with those with deviated mandibular prognathism (Group B) in Korea. All the data were obtained from 3D-reformatted cone-beam computed tomography images from each institute. The right and left condylar heads were located more posteriorly, inferiorly, and medially in Group B than in Group A. The deviated side of Group A and the contralateral side of Group B showed similar condylar width and height, ramus-proper height, and ramus height. Interestingly, there were no inter-group differences in the ramus-proper heights. Asymmetric mandibular body length was the most significantly correlated with chin asymmetry in retrognathic asymmetry patients whereas asymmetric elongation of condylar process was the most important factor for chin asymmetry in deviated mandibular prognathism. CONCLUSION: Considering the 3D positional difference of gonion and large individual variations of frontal ramal inclination, significant structural deformation in deviated mandibular prognathism need to be considered in asymmetric prognathism patients. Therefore, Individually planned surgical procedures that also correct the malpositioning of the mandibular ramus are recommended especially in patients with asymmetric prognathism.

What Is the Linear Accuracy of Regional Voxel-Based Registration for Orthognathic Surgery Landmarks?

PURPOSE: While regional voxel-based registration (R-VBR) has been shown to have excellent reproducibility and angular accuracy, there are limited data on the linear accuracy of R-VBR for common orthognathic surgery landmarks, or on whether angular accuracy correlates with linear accuracy. The purpose of this study was to estimate the linear accuracy of R-VBR for several skeletal landmarks commonly used in orthognathic surgical planning, and to measure the correlation between angular and linear discrepancies. MATERIALS AND METHODS: This is a retrospective cross-sectional study of consecutive patients treated at a single center with nonsegmental LeFort I and bilateral sagittal split osteotomy surgery from January 2019 to November 2020. Cone beam computed tomography at the preoperative (T0) and immediate postoperative (T1) stages were analyzed to measure the postoperative positional changes of 11 orthognathic landmarks in 4 regions of interest (ROI) using R-VBR performed twice by two examiners. Pairwise correlation analysis and canonical correlation analysis were performed for the angular discrepancies (primary predictor variable) and the linear discrepancies (primary outcome variable) to measure the correlation between the two. RESULTS: In cone beam computed tomography analysis of 28 eligible subjects (16 males, 12 females; mean age 18.9 years, range 15 to 25), the mean absolute (MA) angular discrepancies ranged from 0.15° to 0.55°, while the corresponding MA linear discrepancies ranged from 0.05 to 0.41 mm. There was a strong correlation between angular and linear discrepancies that was statistically significant (P = .001 to .04, Spearman's rank correlation coefficient 0.38 to 0.87). CONCLUSIONS: For nonsegmental LeFort I osteotomies and bilateral sagittal split osteotomy, R-VBR has excellent linear accuracy within a single voxel size (0.3 mm) for commonly used orthognathic landmarks in the maxillary and distal mandibular ROI. The MA linear discrepancy for the proximal mandibular segment ROI was greater than a single voxel size, with a maximum of 0.41 mm.

rhBMP-2-Conjugated Three-Dimensional-Printed Poly(L-lactide) Scaffold is an Effective Bone Substitute.

BACKGROUND: Bone growth factors, particularly bone morphogenic protein-2 (BMP-2), are required for effective treatment of significant bone loss. Despite the extensive development of bone substitutes, much remains to be desired for wider application in clinical settings. The currently available bone substitutes cannot sustain prolonged BMP-2 release and are inconvenient to use. In this study, we developed a ready-to-use bone substitute by sequential conjugation of BMP to a three-dimensional (3D) poly(L-lactide) (PLLA) scaffold using novel molecular adhesive materials that reduced the operation time and sustained prolonged BMP release. METHODS: A 3D PLLA scaffold was printed and BMP-2 was conjugated with alginate-catechol and collagen. PLLA scaffolds were conjugated with different concentrations of BMP-2 and evaluated for bone regeneration in vitro and in vivo using a mouse calvarial model. The BMP-2 release kinetics were analyzed using ELISA. Histological analysis and micro-CT image analysis were performed to evaluate new bone formation. RESULTS: The 3D structure of the PLLA scaffold had a pore size of 400 µm and grid thickness of 187-230 µm. BMP-2 was released in an initial burst, followed by a sustained release for 14 days. Released BMP-2 maintained osteoinductivity in vitro and in vivo. Micro-computed tomography and histological findings demonstrate that the PLLA scaffold conjugated with 2 µg/ml of BMP-2 induced optimal bone regeneration. CONCLUSION: The 3D-printed PLLA scaffold conjugated with BMP-2 enhanced bone regeneration, demonstrating its potential as a novel bone substitute.

Secondary healing property using Neoveil®, a polyglycolic acid bioabsorbable sheet on the oral mucosal defects.

Neoveil® is a wound surface-covering agent composed of polyglycolic acid(PGA) effective for secondary healing. This study evaluated the secondary healing property of oral cavity mucosal defects using the PGA sheet. Thirty-four patients who underwent surgical excision of oral benign and malignant lesions, precancerous lesions, and tumors were evaluated. The PGA sheet was placed over the open wound to aid secondary healing. The defects were reviewed post-operatively for secondary healing, contracture, and secondary deformity. Male to female ratio was 20:14, and the mean age was 63.5 years. In all cases, the oral mucosal defect was present after the wide excision of the mucosal lesion. The PGA sheet was used as a surface covering agent which was found to be effective in secondary healing of the wound. Any side effects and adverse reactions which were caused by the PGA sheet was not evident. It can be used to avoid skin graft or free flap reconstruction or deformity from the direct closure in moderate size oral mucosal defect.

Zygoma and Mandibular Angle Reduction: Contouring Surgery to Correct the Square Face in Asians.

Changing the facial appearance with facial contouring surgery is popular, especially in East Asian countries where a square face is a common chief complaint. Mandibular angle reduction, malar reduction, genioplasty, and chin and body contouring surgery can be performed as independent or ancillary procedures during orthognathic surgery. Many techniques have been developed and different osteotomy designs have been proposed to enhance outcomes and minimize complication risks. Here, we review the surgical techniques and considerations for mandibular angle and malar reduction, the two most commonly performed contouring surgeries in East Asia to correct the square face.

Do We Need Safety Nets for Outsourced Computer-Aided Orthognathic Planning? A Two-Center Analysis.

PURPOSE: While the accuracy, cost-effectiveness, and time-efficiency of computer-aided orthognathic surgical planning (CAOP) have been studied, little is known about the influence of logistical factors of outsourced CAOP (OS-CAOP) on patient care. The purpose of this study was to investigate the limitations of OS-CAOP and their effect on treatment planning workflow and surgical outcomes. METHODS: A retrospective cross-sectional study was designed involving subjects who had undergone orthognathic surgery using CAOP from 2 academic oral and maxillofacial surgery centers in South Korea (Kyungpook National University, KNU) and the United States (University of Illinois Chicago, UIC) over an 8-year period. The primary predictor variable was use of modifications or alternatives to OS-CAOP. The primary outcome variable was the frequency of planning changes due to reasons that may have affected outcomes. Covariates included age and sex. Descriptive statistics was used, in addition to a chi-square test to analyze differences among categorical variables. RESULTS: Of a total of 642 eligible subjects in both centers, 5.8% used alternatives to OS-CAOP. 78.4% of these were due to reasons that may have affected outcomes (P < .001), representing 4.5% of all cases. The frequency of the need for OS-CAOP alternatives was identical in both centers (5.8%), but the specific reasons varied, with KNU having mostly plan-related changes (38.1% of alternatives), and UIC with more access and education-related reasons (68.8% of alternatives). At KNU, 71.4% of all alternatives were by repeat OS-CAOP, whereas at UIC, all were by in-house CAOP (IH-CAOP). CONCLUSIONS: In 2 major academic oral and maxillofacial surgery centers in South Korea and the United States, a substantial portion of OS-CAOP required pre-surgical modification, or use of alternatives. Most of the changes were for reasons that could potentially impact outcomes, prompting the need to consider establishing a "safety net" plan compatible with individual clinician's practice setting and healthcare system.

Management of Chronic Idiopathic Pain in Patients With Dental Implant Without a Clear Pathological Lesion: A Retrospective Study.

Non-nociceptive, persistent idiopathic facial pain (PIFP) is a poorly localized, continuous dull pain that occurs even in the absence of apparent pathological lesions or clinical neurologic deficiency. This study aimed to investigate the disease characteristics of PIFP that developed after dental implant treatment. The clinical characteristics of pain as well as treatment method and outcomes were retrospectively analyzed in 20 patients diagnosed with PIFP. The patients developed pain either after implant fixation or prosthetic treatment. In most patients, the pain persisted not only around the implant region but also at a distant site from the related implant (13/20, 65%). Many patients desired removal of the implants to manage the pain although the pain was not considered to be related to the implant treatment. In 12 patients, the related implants were removed, but 67% (n = 8/12) of the patients still experienced chronic pain after implant removal. Medication helped decrease the pain in most patients (n = 17). Pregabalin and clonazepam showed relatively higher efficiency than other medications for controlling the pain. The results showed that although the onset of PIFP was related to dental implant treatment, implant removal could not be considered a reliable option for the management of PIFP. Although medication controls the pain at least partially, complete pain control with medication should not be expected. These results demonstrate that an accurate diagnosis of PIFP is important for the selection of appropriate treatment.

Aspergillosis of the Maxillary Sinus Associated With Dental Implant.

Aspergillosis is a fungal disease caused by the fungus Aspergillus; this disease frequently involves the lungs and occasionally the maxillary sinus. Aspergillosis in the maxillary sinus usually has the characteristics of a noninvasive form. It has been suggested that spores of aspergillus can be inhaled into the maxillary sinus via the osteomeatal complex or via an oroantral fistula after dental procedures, such as an extraction. However, maxillary aspergillosis related to implant installation has rarely been reported. This report regards unusual cases of maxillary aspergillosis associated with dental implant therapies in healthy patients. The cases were successfully treated with the surgical removal of the infected or necrotic tissues.

What Do We Know Beyond Reliability in Voxel-Based Registration? Validation of the Accuracy of Regional Voxel-Based Registration (R-VBR) Techniques for Orthognathic Surgery Analysis.

PURPOSE: Despite having excellent reproducibility, the accuracy of regional voxel-based registration (R-VBR) techniques used for postoperative orthognathic surgical analysis has not been validated. The purpose of this study was to validate the accuracy of R-VBR. METHODS: Preoperative (T0) and postoperative (T1) cone beam computed tomography (CBCT) of consecutive patients treated at a single center with nonsegmental LeFort I and bilateral sagittal split osteotomy were included. T1 CBCTs were oriented to match that of the standardized T0, and thus were assigned a known rotational transformation matrix in pitch/roll/yaw (P/R/Y), to create T1-prime (T1'). A copy of T1 (cT1) was made and was superimposed to T1' using R-VBR for 4 regions of interest (ROI): maxilla, distal mandible, right proximal mandible, and left proximal mandible, to create cT1'. The transformation matrix for each of the ROI was compared to those of T1' using paired t test and Bland-Altman analysis. RESULTS: Twenty-eight eligible subjects' CBCTs were analyzed. Mean difference between T1' and cT1' ranged from -0.08 to 0.14° (maximum 0.73°), with no statistically significant differences (P = 0.216 to 1). Mean absolute difference ranged from 0.13 to 0.31° (maximum 0.73°). Bland-Altman analysis showed good agreement between T1' and cT1', indicating excellent accuracy. CONCLUSIONS: R-VBR using the maxilla, distal mandible, and the bilateral proximal mandibular segments as ROI has excellent accuracy in terms of rotational measurements.

Experience of patients diagnosed as asymptomatic COVID-19 after dental treatment.

BACKGROUND: The potential risk of coronavirus disease 2019 (COVID-19) transmission from asymptomatic COVID-19 patients is a concern in dental practice. However, the impact of this risk is not well documented to date. This report describes our dental clinical experience with patients who did not exhibit symptoms of COVID-19 but were later confirmed as positive for COVID-19. CASE PRESENTATION: Of the 149,149 patients who visited the outpatient clinic of KNUDH and the 3291 patients who visited the Oral and Maxillofacial Surgery Clinic of KNUH, 3 were later confirmed as having COVID-1 between 1 February 2020 and 28 February 2021. Owing to close contact with these patients during their treatments, 46 dental and medical staff had to undergo quarantine from the date of the patients' confirmation of COVID-19 infection. CONCLUSION: The presented cases showed the potential existence of asymptomatic COVID-19 patients after dental treatment with aerosol-generating procedures. Clinicians should be aware of the infection prevention measures and try to protect healthcare personnel from secondary infection of COVID-19 during dental treatments.

The impact of COVID-19 on the injury pattern for maxillofacial fracture in Daegu city, South Korea.

BACKGROUND: This study aimed to analyze the impact of COVID-19 on oral and maxillofacial fracture in Daegu by comparing the demographic data in 2019 and 2020, retrospectively. We collected data from all patients having trauma who visited the emergency room for oral and maxillofacial fractures. METHODS: This retrospective study was based on chart review of patients who visited the emergency department of Kyungpook National University Hospital in Daegu, South Korea from January 1, 2019, to December 31, 2020. We conducted a comparative study for patients who presented with maxillofacial fractures with occlusal instability during pre-COVID-19 era (2019) and COVID-19 era (2000) with demographics and pattern of injuries. RESULTS: After the outbreak of COVID-19, the number of monthly oral and maxillofacial fractures, especially sports-related oral and maxillofacial fractures, decreased significantly. Also, the number of alcohol-related fractures increased significantly. In addition, as the number of monthly confirmed cases of COVID-19 increases, the incidence of fracture among these cases tends to decrease. CONCLUSIONS: The COVID-19 pandemic has changed the daily life in Korea. Identifying the characteristics of patients having trauma can provide a good lead to understand this long-lasting infectious disease and prepare for future outbreaks.

Differential Angiogenic Potential of 3-Dimension Spheroid of HNSCC Cells in Mouse Xenograft.

The experimental animal model is still essential in the development of new anticancer drugs. We characterized mouse tumors derived from two-dimensional (2D) monolayer cells or three-dimensional (3D) spheroids to establish an in vivo model with highly standardized conditions. Primary cancer-associated fibroblasts (CAFs) were cultured from head and neck squamous cell carcinoma (HNSCC) tumor tissues and co-injected with monolayer cancer cells or spheroids into the oral mucosa of mice. Mice tumor blood vessels were stained, followed by tissue clearing and 3D Lightsheet fluorescent imaging. We compared the effect of exosomes secreted from 2D or 3D culture conditions on the angiogenesis-related genes in HNSCC cells. Our results showed that both the cells and spheroids co-injected with primary CAFs formed tumors. Interestingly, vasculature was abundantly distributed inside the spheroid-derived but not the monolayer-derived mice tumors. In addition, cisplatin injection more significantly decreased spheroid-derived but not monolayer-derived tumor size in mice. Additionally, exosomes isolated from co-culture media of FaDu spheroid and CAF upregulated angiogenesis-related genes in HNSCC cells as compared to exosomes from FaDu cell and CAF co-culture media under in vitro conditions. The mouse tumor xenograft model derived from 3D spheroids of HNSCC cells with primary CAFs is expected to produce reliable chemotherapy drug screening results given the robust angiogenesis and lack of necrosis inside tumor tissues.

Analysis of Factors Associated with the Postoperative Healing of Medication-Related Osteonecrosis of the Jaw in Patients with Osteoporosis.

BACKGROUND: Surgical treatment is considered the best approach by many researchers for medication-related osteonecrosis of the jaws (MRONJ). While postoperative outcomes are mainly favorable, wound healing still fails in some cases. This retrospective study aimed to evaluate the factors affecting the postoperative healing of MRONJ. METHODS: This study involved 400 osteoporosis patients who received surgical treatment from January 2009 to January 2018 in Kyungpook National University Hospital. The patient, drug, and clinical factors were collected as investigation variables. The obtained data were statistically analyzed to identify relationships between the factors and healing aspect. RESULTS: Univariate logistic regression analysis showed that the route of drug administration, bone exposure, types of surgical management, and wound management had a significant influence (p < 0.05) on the healing outcome. Sequestrectomy with primary closure had a more positive effect on favorable healing. In the multivariate logistic regression test, the effect of wound management alone was not statistically significant (p > 0.05). CONCLUSION: In patients with osteoporosis, the factors such as intravenously administered drugs, fistulas that were probed to the bone, and surgical management with curettage were associated with a lower rate of postoperative complete healing of MRONJ, whereas primary closure of wounds led, possibly, to good healing outcomes. The strengths of the study include its relatively large sample size and that its results can hopefully aid in the clinical decisions for practitioners and future research studies for researchers.

Characteristics of patients with osteonecrosis of the jaw with oral versus intravenous bisphosphonate treatment.

PURPOSE: This retrospective study was aimed to evaluate the clinical characteristics and treatment outcomes in patients with osteonecrosis of the jaw who were receiving oral versus intravenous (IV) bisphosphonate (BP). MATERIALS AND METHODS: This retrospective study enrolled subjects who had been diagnosed with medication-related osteonecrosis of the jaw (MRONJ) during the period from July 2010 to June 2014. Information regarding the following demographic and clinical characteristics was collected: demographic data, administration route and type of BP, duration of BP medication, primary disease, number of involved sites, location of the lesion, number of surgeries, outcome of treatments, and laboratory test. All the patients were divided into oral and IV BP groups; and the between-group differences were compared. RESULTS: Total 278 patients were divided into two groups as per the route of BP administration. The proportion of oral BP-related MRONJ group were more dominant over IV BP group (oral BP, n = 251; IV BP, n = 27). In the IV BP group, the average dosing duration (31.4 months) was significantly shorter than that in the oral BP group (53.1 months) (P < 0.001). The average number of involved sites in the oral BP group (1.21 ± 0.48) was smaller than that in the IV BP group (1.63 ± 0.84) (P < 0.001). The average number of surgeries was higher in the IV BP group (1.65 ± 0.95) as compared to that in the oral BP group (0.98 ± 0.73) (P < 0.001). Outcome after the surgery for MRONJ after IV BP was poor than oral BP group. CONCLUSION: IV administration of BP causes greater inhibition of bone remodeling and could lead more severe inflammation. Therefore, even if the duration of IV administration of BP is shorter than that of oral BP, the extent of the lesion could be more extensive. Therefore, the result suggests that the MRONJ after IV BP for cancer patients needs to be considered as different characteristics to oral BP group for osteoporosis patents.

Cancer-Associated Fibroblast Subgroups Showing Differential Promoting Effect on HNSCC Progression.

Background: The critical effect of the tumor microenvironment on cancer progression is well recognized. Recent research suggests that the cancer-promoting properties of the tumor stroma may be attributed to fibroblasts. However, the effect of cancer-associated fibroblast (CAF) on the progression of head and neck squamous cell carcinoma (HNSCC) is not well known. Methods: From the immunohistochemical analysis of head and neck squamous cell carcinoma (HNSCC) tissues, we divided CAF into two groups depending on the presence or absence of a well-demarcated boundary between epithelial cancer cells and the surrounding extracellular matrix (ECM). Primary culture of CAF was performed, followed by co-transplantation with HNSCC cells into mice oral mucosa, and the tumorigenesis was compared. The mRNA expression patterns between these two CAF groups were compared using DNA microarray analysis. Results: CAFs from cancer tissues that showed no demarcation between ECM and epithelial cancer cells (CAF-Promote) tended to stimulate Matrigel invasion of HNSCC cells. Conversely, CAFs from cancer tissues that showed a boundary with epithelial cancer cells (CAF-Delay) caused no remarkable increase in Matrigel invasion. Compared with CAF-P, CAF-D is less effective in promoting FaDu tumorigenicity in the mouse model. In DNA microarray analysis, COL3A1 and COL6A6 showed particularly high expression in the CAF-D group. Conclusions: These cancer stroma-derived collagen proteins might delay the HNSCC progression. These findings are expected to provide vital information for predicting HNSCC prognosis and developing drug targets in the future.

Comparing factors affecting dental-implant loss between age groups: A retrospective cohort study.

BACKGROUND: There is a growing interest in factors leading to implant failure in older people as the population aged 65 years or older continues to expand. PURPOSE: We sought to identify differences of results in the implant survival rate and the influence of certain factors on implant failure in the older (≥65 years) and younger (<65 years) patients. MATERIALS AND METHODS: Patients who underwent their first dental-implant surgery between July 2008 and June 2018 were included. Data on age, sex, smoking habits, medical conditions, implant location, implant size, and the presence and type of bone graft and membrane were collected and analyzed according to age group. Moreover, cumulative survival rates of implants (by Kaplan-Meier analysis) and hazard ratios (HR) of each factor (using Cox regression analysis with shared frailty) in each group were assessed and results compared between groups. RESULTS: A total of 628 implants in 308 patients and 1904 implants in 987 patients in the older and younger groups, respectively, were assessed, with failure rates of 3.9% and 3.4%. Per Kaplan-Meier analysis, the 11-year patient-level cumulative survival rate of implant treatment was 95.3% (95% CI: 0.91-0.97) in the older and 93.9% (95% CI: 0.88-0.97) in the younger group. The HR for implant failure of the variables, except diameter of dental implants, were not statistically significant in both groups. CONCLUSION: The outcomes of implant treatment were not considerably different between the age groups.