Morphometric Assessment of Alveolar Antral Artery Using Medical Computed Tomography.

This study aimed to investigate the prevalence, diameter, and position of the alveolar antral artery (AAA) in paranasal sinus computed tomography (CT) images and to correlate the location of the AAA with tooth position, the presence of teeth, and residual alveolar bone height (ABH). A retrospective study was conducted at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital, from November 2016 to October 2021. CT images of 100 maxillary sinuses from 50 patients managed for modified endoscopic sinus surgery and sinus lifting by a single surgeon were selected and obtained from the Infinitt picture archiving and communication system radiology system (Infinitt Healthcare Co., Seoul, Korea). The location of the AAA in the lateral wall of the maxillary sinus was evaluated in correlation with the area of the first and second molars (M1 and M2), the presence of teeth, and the residual ABH. In this study, we found that the intraosseous type is the most common type of AAA. Furthermore, the location and distance of the AAA are significantly affected by tooth position, an edentulous state in the case of the first molar, and residual ABH. Pre-evaluation of the diameter, position, and distance to the AAA using CT images is essential to help prevent hemorrhage. The existence and wide range of the AAA distances based on the tooth position, edentulous state, and residual ABH should be considered even if CT imaging cannot locate the AAA.

Anterior Dental Implant in Grafted Cleft Alveolus: A Clinical Comparison Between Intramembranous and Endochondral Bone Graft.

BACKGROUND: Alveolar bone graft is usually performed during the early mixed dentition phase, at the chronological age of 6 to 8 years old, to reconstruct the cleft alveolus. As the appropriate time for implant placement is after completion of full growth, it can result in a likelihood of resorption. The aim of this study is to compare the clinical outcomes of anterior dental implants with delayed bone grafting using iliac crest (endochondral) and mandibular ramus or symphysis (intramembranous) bone in adolescents to adulthood patients with cleft alveolus. MATERIALS AND METHODS: This study included 10 patients with cleft alveolus who underwent delayed bone grafting with autogenous block bone and particulate cancellous bone and marrow (PCBM) from the mandibular ramus and symphysis with dental implant placement, and iliac crest. The success of the treatment was evaluated through clinical and radiographic examination including marginal bone loss measurement of the implants. RESULTS: All patients underwent delayed bone grafting between the ages of 11 and 21.1 years (mean age: 15.1±4.3 y). The implant diameters ranged from 3.8 to 4.5 mm and the lengths ranged from 8.0 to 11.5 mm. All of the implants were integrated successfully and survived during the 3-year follow-up period. CONCLUSIONS: Delayed bone grafting followed by implant placement showed long-term stability with satisfactory esthetic and functional rehabilitation. One of the main advantages of delayed bone grafting is to achieve adequate bone support for future dental implant placements with less bone resorption compared with those of primary, early secondary, and secondary bone grafting.

Appropriate Implant Rehabilitation in Patients With Iatrogenic Oroantral Fistula and Odontogenic Maxillary Sinusitis.

Oroantral fistula (OAF) is the most common etiology for odontogenic maxillary sinusitis that can be caused by tooth extractions, failed maxillary sinus lifts, bone grafts, and poor positioning of dental implant fixtures. A 52-year-old man presented with an OAF and maxillary sinusitis after implant placement and bone grafting. The authors treated the patient with modified endoscopic sinus surgery to obtain OAF closure and provided dental implant placement procedures afterward. The authors also treated 8 other similar cases with favorable outcomes. In this study, the authors report the know-how of implant placement procedures in patients with OAF and maxillary sinusitis.

Immune Responses to the ChAdOx1 nCoV-19 and BNT162b2 Vaccines and to Natural Coronavirus Disease 2019 Infections Over a 3-Month Period.

BACKGROUND: There are limited data directly comparing immune responses to vaccines and to natural infections with coronavirus disease 2019 (COVID-19). This study assessed the immunogenicity of the BNT162b2 and ChAdOx1 nCoV-19 vaccines over a 3-month period and compared the immune responses with those to natural infections. METHOD: We enrolled healthcare workers who received BNT162b2 or ChAdOx1 nCoV-19 vaccines and patients with confirmed COVID-19 and then measured S1 immunoglobulin (Ig) G and neutralizing antibodies and T-cell responses. RESULTS: A total of 121 vaccinees and 26 patients with confirmed COVID-19 were analyzed. After the second dose, the BNT162b2 vaccine yielded S1 IgG antibody responses similar to those achieved with natural infections (mean IgG titer [standard deviation], 2241 [899] vs 2601 [5039]; P = .68) but significantly stronger than responses to the ChAdOx1 vaccine (174 [96]; P < .001). The neutralizing antibody titer generated by BNT162b2 was 6-fold higher than that generated by ChAdOx1 but lower than that by natural infection. T-cell responses persisted for 3 months with BNT162b2 and natural infection but decreased with ChAdOx1. CONCLUSIONS: Antibody responses after the second dose of BNT162b2 are higher than after the second dose of ChAdOx1 and like those occurring after natural infection. T-cell responses are maintained longer in BNT162b2 vaccinees than in ChAdOx1 vaccinees.

Legal Liability of a Dentist: Inferior Alveolar Nerve Damage After Calcium Hydroxide Extrusion.

ABSTRACT: During root canal treatments, calcium hydroxide can extrude through the apex causing chemical, mechanical, and/or thermal injuries to the inferior alveolar nerve, which can lead to neurological disorders. unfortunately, dental practitioner negligence can produce this potentially life-changing injury that can compromise the patient's life. The aim of this study is present a case of dental negligence by calcium hydroxide extrusion causing inferior alveolar nerve damage, discuss the methods of prevention, and characterize the medico-legal aspects of complication.

A Life-Saving Early Diagnosis of Burkitt Lymphoma: The Role of a Dentist.

ABSTRACT: Burkitt lymphoma (BL) is a subtype of Non-Hodgkin lymphoma, considered one of the fastest growing human tumors. Due to the highly aggressive nature of BL, a prompt diagnosis and aggressive chemotherapeutic treatment are essential. However, the clinical features of BL often can mimic periodontal disease or dentoalveolar abscess. The aim of this study is to present a case of a 31-year-old male patient who was referred to the department of oral and maxillofacial surgery for severe neurosensory disturbance and pain in the lower jaw. He was misdiagnosed with periodontitis and dental abscess at the local clinic. Based on radiographic findings, he was suspected of hematopoietic malignancy. He was referred to the department of hemato-oncology and diagnosed with BL. This case highlights the essential life-saving role of a maxillofacial surgeon in the early diagnosis of a rare malignancy.

Decompressive effects of draining tube on suppurative and sclerosing osteomyelitis in the jaw.

BACKGROUND: Osteomyelitis (OM) in the jaw is an inflammatory disease of osseous tissue that begins in the medullary space and progressively expands to the cortical portion of the bone, the Haversian system, the periosteum and the overlying soft tissue. Despite advances in dental and medical care, OM persists and is of important concern in modern medicine. Active negative pressure is known to prevent post-operative hematoma; decrease the number of bacterial pathogens, accumulation of toxins, and necrotic tissue; and promote osteogenesis and angiogenesis with the use of a draining tube such as the Jackson-Pratt (JP) or Hemovac. The purpose of this study was to assess the effectiveness of decompression for the treatment of OM in the jaw. METHODS: This retrospective study included a total of 130 patients, 55 patients with sclerosing OM and 75 patients with suppurative OM were included. The radiographic bone densities expressed as a grayscale values (GSVs), were measured using an easy digitalized panoramic analysis (EDPA) method, processed on the conditional inference tree, generated by the R program® 3.2.3 with a probability of 96.8%. Rectangle annotation analysis of INFINITT PACS® (INFINITT Healthcare, Seoul, Korea) of 50 mm2 was determined as the region of interest (ROI). Student's t-test and ANOVA were used to determine significance (p < 0.05). RESULTS: Significant changes was observed between radiographic bone density in the sclerosing type with drain and without drain at the six-month and one-year follow-up (p < 0.05). Significant difference was demonstrated between the suppurative OM with drain and without drain groups at the one-year follow-up (p < 0.05). CONCLUSION: The OM groups with drain exhibited more enhanced bone density compared to the groups without drain at the six-month and one-year follow-ups. The drain insertion for decompression is effective for the management of sclerosing and suppurative OM. It is recommended to implement it for the management of OM.

Effects of pentoxifylline and tocopherol on a rat-irradiated jaw model using micro-CT cortical bone analysis.

PURPOSE: A combination of pentoxifylline (PTX) and tocopherol (TP) is believed to reduce chronic fibrosis and induce bone healing in osteoradionecrosis (ORN) of the mandible, but evidence of its therapeutic effectiveness for cortical bone is lacking. This study was designed to determine the effect of combined PTX and TP (PTX + TP) on mandibular cortical bone remodeling in a rat model of ORN, using micro-CT and histological analysis. METHODS: Forty-eight 8-week-old male Sprague-Dawley rats were randomly divided into irradiated (n = 40) and non-irradiated (n = 8) groups. Animals in the irradiated group were divided into four sub-groups, including PTX, TP, PTX + TP, and normal saline. Three weeks after irradiation, mandibular posterior tooth extraction was performed, and animals were sacrificed 7 weeks after irradiation. The mandibles were analyzed using micro-CT and histological evaluation. RESULTS: The alveolar bone height, cortical bone thickness, cortical bone volume, and total cortical bone surface of the PTX + TP group were significantly greater than those of other irradiated groups (p < 0.05). In 3D reconstructed images, the residual volumes of cortical and cancellous bone were inadequate in the irradiated groups. CONCLUSION: We found that a combination of PTX and TP improved quality and quantity of cortical bone in irradiated rat mandibles, thus providing supporting evidence of its utility as a treatment and prophylactic agent in ORN. We observed inadequate volumes of cortical and cancellous bone in ORN mandibles, suggesting that cortical bone could play an important role in further ORN studies.

Autogenous Partial Bone Chip Grafting on the Exposed Inferior Alveolar Nerve After Cystic Enucleation.

This prospective study evaluated the clinical effectiveness of the new approach of partial autogenous bone chip grafts for the treatment of mandibular cystic lesions related to the inferior alveolar nerve (IAN). A total of 38 patients treated for mandibular cysts or benign tumors were included in this prospective study and subsequently divided into 3 groups depending on the bone grafting method used: cystic enucleation without a bone graft (group 1), partial bone chip graft covering the exposed IAN (group 2), and autogenous bone graft covering the entire defect (group 3). We evaluated the symptoms, clinical signs, and radiographic changes using dental panorama preoperatively, immediate postoperatively, and at 1, 3, 6, and 12 months postoperatively. Radiographic densities were compared using Adobe Photoshop CS5 (Adobe Systems Inc., San Jose, CA). Repeated measures analysis of variance was used for statistical evaluation with SPSS 22.0 (SPSS Inc, Chicago, IL), and P < 0.05 was considered statistically significant.Radiopacities were the most increased at 1 year postoperative in group 3; groups 2 and 3 did not show statistically significant differences, whereas groups 1 and 3 were statistically significant. In terms of radiographic bone healing with clinical regeneration of the exposed IAN, healing occurred in all patients, although the best healing was achieved in group 2.This autogenous partial bone chip grafting procedure to cover the exposed IAN is suggested as a new surgical protocol for the treatment of cystic lesions associated with the IAN.

Analysis of Microvascular Free Flap Failure Focusing on the Microscopic Findings of the Anastomosed Vessels.

Microvascular flap reconstruction is known as successful technique, although vascular thrombosis can cause free flap failure. To analyze the histologic characteristics and causes of free flap failure, this clinical study examined failed free flaps, including the microanastomosed sites. This study included a total of 5 failed flaps, including 3 radial forearm free flaps, 1 latissimus dorsi free flap, and 1 fibular free flap, all performed with microvascular reconstruction surgery from 2009 to 2011 at Seoul National University Dental Hospital. At the resection surgeries of the failed nonviable flaps, histologic specimens including the microanastomosed vessels were acquired. For light microscope observation, the slides were stained with hematoxylin and eosin (HE), and also with Masson trichrome. Selected portions of graft tissue were also observed under transmission electron microscope (TEM). It was found that the cause of flap failure was the occlusion of vessels because of thrombi formation. During the microanastomosis, damage to the vessel endothelium occurred, followed by intimal hyperplasia and medial necrosis at the anastomosed site. In the TEM findings, some smooth muscle cells beneath endothelium were atrophied and degenerated. The formation of thrombi and the degeneration of the smooth muscle cells were coincident with vascular dysfunction of graft vessel. The damaged endothelium and the exposed connective tissue elements might initiate the extrinsic pathway of thrombosis at the microanastomotic site. Therefore, it is suggested that accurate surgical planning, adequate postoperative monitoring, and skillful technique for minimizing vascular injury are required for successful microvascular transfer.

Bell's palsy after concomitant chemoradiotherapy: a case report and literature review.

Concomitant chemoradiotherapy (CCRT) treated patients experience various complications. We present a rare case of post-CCRT Bell's palsy and describe its various possible causes, so as to increase awareness among clinicians about Bell's palsy being a CCRT-associated adverse effect. The patient was a 48-year-old man diagnosed with squamous cell carcinoma who presented with post-CCRT Bell's palsy. After radiotherapy for 6 weeks (overall 67.5 Gy) and four rounds of cisplatin chemotherapy, he complained of paralysis of the entire left face. A test was performed 33 days after the last CCRT session to differentiate Bell's palsy from other causative factors. Based on magnetic resonance imaging findings, facial nerve invasion due to tumor size increase was determined to not cause Bell's palsy. Inflammation of the left Eustachian tube was observed. Hence, steroids and famciclovir were administered, which markedly improved the facial paralysis symptoms within 56 days after facial paralysis development. In conclusion, patients can develop Bell's palsy owing to complex effects of various CCRT mechanisms. Although the exact cause of Bell's palsy has not been identified and the effectiveness of drug treatment was questionable in this case, unlikely causative factors should be excluded through various tests and appropriate and timely measures must be adopted.

Clinical retrospective analysis of peri-implant oral malignancies.

PURPOSE: Complications of implant prostheses have direct correlation with the increased use of implants for dental rehabilitation. In this study, we present cases of peri-implant oral malignancies (PIOM) around dental implants and a retrospective analysis of patients treated for PIOM. METHODS: The retrospective analysis was performed with patients treated for PIOM at the Department of Oral and Maxillofacial Surgery of the Seoul National University Dental Hospital between 2006 and 2014. The patient records were thoroughly screened for previous medical issues, human papilloma virus infections, and other clinical data with a focus on relevant information such as localization, time from implant insertion to the development of the carcinoma, implant type and prosthetic rehabilitation. RESULTS: Twenty-one patients were diagnosed with PIOM. The male-to-female ratio was 1.625. The mean age of the patients was 60.42 ± 9.35 years old. Three patients reported ongoing alcohol/tobacco consumption. Five patients had a history of previous oral cancer surgery or exhibited mucosal lesions. The time from implant placement until carcinoma diagnosis was 49.13 ± 33.63 months on average. Most PIOM patients (95.2%) were diagnosed with SCC. All patients had previously been treated for peri-implantitis. In 85.7% of the patients, prostheses were observed on the opposing teeth where PIOM occurred. CONCLUSION: Based on the review of these cases, it can be deduced that there is a possibility that implant treatment and galvanic currents between prosthesis may constitute an irritant and/or inflammatory cofactor which contributes to the formation and/or development of malignant tumors. Patients at potential risk may benefit from individualized recall intervals and careful evaluations.

Ultrastructural and immunohistochemical evaluation of hyperplastic soft tissues surrounding dental implants in fibular jaws.

In reconstructive surgery, complications post-fibula free flap (FFF) reconstruction, notably peri-implant hyperplasia, are significant yet understudied. This study analyzed peri-implant hyperplastic tissue surrounding FFF, alongside peri-implantitis and foreign body granulation (FBG) tissues from patients treated at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. Using light microscopy, pseudoepitheliomatous hyperplasia, anucleate and pyknotic prickle cells, and excessive collagen deposition were observed in FFF hyperplastic tissue. Ultrastructural analyses revealed abnormal structures, including hemidesmosome dilation, bacterial invasion, and endoplasmic reticulum (ER) swelling. In immunohistochemical analysis, unfolded protein-response markers ATF6, PERK, XBP1, inflammatory marker NFκB, necroptosis marker MLKL, apoptosis marker GADD153, autophagy marker LC3, epithelial-mesenchymal transition, and angiogenesis markers were expressed variably in hyperplastic tissue surrounding FFF implants, peri-implantitis, and FBG tissues. NFκB expression was higher in peri-implantitis and FBG tissues compared to hyperplastic tissue surrounding FFF implants. PERK expression exceeded XBP1 significantly in FFF hyperplastic tissue, while expression levels of PERK, XBP1, and ATF6 were not significantly different in peri-implantitis and FBG tissues. These findings provide valuable insights into the interconnected roles of ER stress, necroptosis, apoptosis, and angiogenesis in the pathogenesis of oral pathologies, offering a foundation for innovative strategies in dental implant rehabilitation management and prevention.

Layered structure of sialoliths compared with tonsilloliths and antroliths.

Objectives: The aim of this study was to perform a comparative analysis of the ultrastructural and chemical composition of sialoliths, tonsilloliths, and antroliths and to describe their growth pattern. Materials and Methods: We obtained 19 specimens from 18 patients and classified the specimens into three groups: sialolith (A), tonsillolith (B), and antrolith (C). The peripheral, middle, and core regions of the specimens were examined in detail by histology, micro-computed tomography (micro- CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and transmission electron microscopy (TEM). Results: In the micro-CT, group A showed alternating radiodense and radiolucent layers, while group B had a homogeneous structure. Group C specimens revealed a compact homogeneous structure. Histopathologically, group A showed a laminated, teardrop-shaped, globular structure. Group B demonstrated degrees of immature calcification of organic and inorganic materials. In group C, the lesion was not encapsulated and showed a homogeneous lamellar bone structure. SEM revealed that group A showed distinct three layers: a peripheral multilayer zone, intermediate compact zone, and the central nidus area; groups B and C did not show these layers. The main elemental components of sialoliths were O, C, Ca, N, Cu, P, Zn, Si, Zr, F, Na, and Mg. In group B, a small amount of Fe was found in the peripheral region. Group C had a shorter component list: Ca, C, O, P, F, N, Si, Na, and Mg. TEM analysis of group A showed globular structures undergoing intra-vesicular calcification. In group B, bacteria were present in the middle layer. In the outer layer of the group C antrolith, an osteoblastic rimming was observed. Conclusion: Sialoliths had distinct three layers: a peripheral multilayer zone, an intermediate compact zone and the central nidus area, while the tonsillolith and antrolith specimens lacked distinct layers and a core.

Influence of vascular twisting on the supermicroanastomosis of superficial inferior epigastric artery.

Arterial microanastomoses with small-caliber vessels, such as those with an internal diameter less than 0.2 mm, are susceptible to inadvertent twisting. A total of 20 supermicroanastomoses were performed in the superficial inferior epigastric artery (SIEA)-based flap model of ten 10-week old, 300- to 350-g male Sprague-Dawley rats. Two rats with 4 flaps comprised each experimental group: a negative control, a control with end-to-end SIEA arterial supermicroanastomosis, and 3 experimental groups (EAs), such as EA1, 2, and 3 with 90-, 180-, and 270-degree twisting supermicroanastomosis, respectively. Each SIEA was clamped with a Superfine Vascular Clamp (S&T Co, Neuhausen, Switzerland) and anastomosed with 6 stitches. On postoperative day 10, the skin flap surface texture had no color change, and skin necrosis was not found in any group within a 1.0-mm grid measurement in less than 1% of the whole skin flap surfaces. There were statistically significant differences between the groups in 4 criteria, such as cellular swelling, nuclear pleomorphism, nuclear swelling, and microvessel numbers. The pulsatility index was increased in the EA1 and EA2 on postoperative days 1 and 2, showing decrease in the similar preoperative value on postoperative day 10, but decreased pulsatility index was continuous in the EA3 during the postoperative day 10. The resistance index was significantly different between preoperative and postoperative day 10 especially in the EA2 and EA3. Ultramicroscopic findings in the EA3 group showed an increase in tunica media necrosis, convolution of the internal elastic lamina, and densely packed platelets, fibrins, and erythrocytes.

Radiographic evaluation before surgical extraction of impacted third molar to reduce the maxillary sinus related complication.

Objectives: Surgical extraction of maxillary third molars is routine in departments devoted to oral and maxillofacial surgery. Because maxillary third molars are anatomically adjacent to the maxillary sinus, complications such as oroantral fistula and maxillary sinusitis can occur. Here we explore the factors that can cause radiographic postoperative swelling of the maxillary sinus mucosa after surgical extraction. Materials and Methods: This retrospective study reviewed the clinical records and radiographs of patients who underwent maxillary third-molar extraction. Preoperative panoramas, Waters views, and cone-beam computed tomography were performed for all patients. The patients were divided into two groups; those with and those without swelling of the sinus mucosa swelling or air-fluid level in a postoperative Waters view. We analyzed the age and sex of patients, vertical position, angulation, number of roots, and relation to the maxillary sinus between groups. Statistical analysis used logistic regression and P<0.05 was considered statistically significant. Results: A total of 91 patients with 153 maxillary third molars were enrolled in the study. Variables significantly related to swelling of the maxillary sinus mucosa after surgical extraction were the age and the distance between the palatal cementoenamel junction (CEJ) and the maxillary sinus floor (P<0.05). Results of the analysis show that the relationship between the CEJ and sinus floor was likely to affect postoperative swelling of the maxillary sinus mucosa. Conclusion: Maxillary third molars are anatomically adjacent to the maxillary sinus and require careful handling when the maxillary sinus is pneumatized to the CEJ of teeth.

Functional rehabilitation of the maxillary sinus after modified endoscopic sinus surgery for displaced dental implants.

PURPOSE: Dental implants may become displaced into the maxillary sinus due to insufficient primary stability, changes in nasal air pressure, or surrounding bone resorption and should be removed as soon as possible. The aim of this study was to evaluate the efficacy of the modified endoscopic sinus surgery (MESS) approach for removal of displaced dental implants. METHODS: From September 2010 to November 2021, we studied 15 cases with displaced implants in the maxillary sinus. The patient characteristics, medical history, clinical and imaging results, and post-removal outcomes were retrospectively assessed. RESULTS: The symptoms included sinusitis (100%), pain (26.6%), postnasal drip (6.6%), nasal obstruction (26.6%), and oroantral communication (26.6%). Two cases were managed through the crestal approach (13.3%), while two cases were treated with the Caldwell-Luc procedure (13.3%). One case was addressed using functional endoscopic sinus surgery (6.7%), while 10 cases were managed with the MESS approach (66.7%). MESS allows functional rehabilitation of mucociliary clearance by the cilia in the sinus membrane. Implant displacement into the maxillary sinus can be classified as early, late, or delayed displacement. CONCLUSIONS: MESS is a reliable treatment option that can identify migrated dental implants in any part of the sinus with endoscopic assistance for functional rehabilitation of the maxillary sinus without postoperative sequelae.

Clinical significance of drug cessation on medication-related osteonecrosis of the jaw in patients with osteoporosis.

Objectives: Suspending bisphosphonates (BPs) to reduce the risk and severity of medication-related osteonecrosis of the jaw (MRONJ) remains controversial. In this study, we quantitatively evaluated the clinical significance of BP suspension before surgery in osteoporosis patients with MRONJ. Materials and Methods: We analyzed 24 osteoporosis patients with MRONJ who were treated from 2012 to 2020 at Seoul National University Dental Hospital and compared the treatment outcomes of those who suspended BPs with those who did not. The number of surgical interventions, follow-up panoramic radiographs for relative bone density measurement, and laboratory blood tests including white blood cells, erythrocyte sedimentation rate, absolute neutrophil count, hemoglobin, hematocrit, and alkaline phosphatase were analyzed. ANOVA, Student's t -test, and Mann-Whitney U tests were used to compare results. Fisher's exact test was used to discover the association between treatment outcome and BP suspension, and Pearson's correlation test was used to measure the statistical relationship between the changes in serum inflammatory markers. Results: The number of interventions was significantly higher in the non-drug suspension group due to recurrence (p<0.05). The relative bone density in patients who suspended BPs was significantly different over time (p<0.05), with the highest density at one-year follow-up. Fisher's exact test shows an association between successful treatment outcomes and BP suspension. The alkaline phosphatase and erythrocyte sedimentation rate levels decreased significantly in the BP-suspended group, and a positive correlation was found between these elevated markers. Conclusion: A significant increase in bone density throughout follow-up and a lower number of interventions were found in the BP suspension group compared to the non-drug suspension group. Also, BP suspension decreased inflammatory markers in the serum after surgery, resulting in good treatment outcomes. BP suspension is a prognostic factor for MRONJ and should be implemented before surgery.

Energy-dispersive X-ray spectroscopic investigation of a fractured non-submerged dental implant associated with abutment fracture.

The biocompatibility and durability of implant fixtures are major concerns for dentists and patients. Mechanical complications of the implant include abutment screw loosening, screw fracture, loss of implant prostheses, and implant fracture. This case report aims to describe management of a case of fixture damage that occurred after screw fracture in a tissue level, internal connection implant and microscopic evaluation of the fractured fixture. A trephine bur was used to remove the fixture, and the socket was grafted using allogeneic bone material. The failed implant was examined by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS), which revealed a fractured fixture with both normal and irregular bone patterns. The SEM and EDS results give an enlightenment of the failed fixture surface micromorphology with microfracture and contaminated chemical compositions. Noticeably, the significantly high level of gold (Au) on the implant surface and the trace amounts of Au and titanium (Ti) in the bone tissue were recorded, which might have resulted from instability and micro-movement of the implant-abutment connection over an extended period of time. Further study with larger number of patient and different types of implants is needed for further conclusion.

Guidance and rationale for the immediate implant placement in the maxillary molar.

Objectives: While the reliability of immediate implant placement in the maxillary molar has been discussed, its significance is questionable. There have been no guidelines for case selection and surgical technique for successful treatment outcomes of immediate maxillary molar implants. Therefore, in this study, we classified alveolar bone height and socket morphology of the maxillary molar to establish guidelines for immediate implant placement. Materials and Methods: From 2011 to 2019, we retrospectively analyzed 106 patients with 148 immediate implants at the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. Inclusion and exclusion criteria were applied, and patient characteristics and treatment results were evaluated clinically and radiologically. Results: A total of 29 tapered, sand-blasted, large-grit, and acid-etched (SLA) surfaces of implants were placed in 26 patients. The mean patient age was 64.88 years. Two implants failed and were reinstalled, resulting in a 93.10% survival rate. Fluctuating marginal bone level changes indicating bone regeneration and bone loss were observed in the first year following installation and remained stable after one year of prosthesis loading, with an average bone loss of 0.01±0.01 mm on the distal side and 0.03±0.03 mm on the mesial side. Conclusion: This clinical study demonstrated the significance of immediate implant placement in maxillary molars as a reliable treatment with a high survival rate using tapered SLA implants. With an accurate approach to immediate implantation, surgical intervention and treatment time can be reduced, resulting in patient satisfaction and comfort.