Regeneration of sensory nerve branches in extraction socket and surrounding alveolar bone in rat: immunohistochemical observation of the axon and myelin sheath changes.

The purpose of this study was to investigate the process and derivation of the distribution of the sensory nerves that appear in the extraction socket and surrounding alveolar bone following tooth extraction. The right mandibular first molar of rats and periodontal ligament were extracted as a single mass, and the mandible was harvested after days 1, 3, 5, and 7 after extraction. Serial sections of 7 µm thickness were prepared for the proximal root (Section A), buccolingual root (Section B), and centrifugal root (Section C) of the first molar. H-E staining and immunohistochemical staining with anti-S100 antibody and anti-NF-L antibody were carried out. The presence of nerve fiber bundles in the blood clot was already evident on post-extraction day 3, and on post-extraction day 7. On day 3, the number of axons in Sections B and C had greatly decreased, indicating that, after extraction, the connection between peripheral nerve tissue and the trigeminal ganglion was temporarily markedly reduced in the region of the alveolar branch. Although the myelin sheaths were regenerating on day 5, the majority of the axons of the alveolar branches extending from the inferior alveolar nerve were seen to be extremely thin and scattered, despite their further regeneration. The above results suggest that the newly myelinated nerves are actually derived from the bone marrow to the extraction socket, so few nerves, rather than being derived from the alveolar branches that had innervated the extracted tooth.

Dimensional changes of buccal bone in the edentulous maxilla with telescopic-retained implant-supported fixed dental prostheses.

STATEMENT OF PROBLEM: The buccal bone in an edentulous maxilla loses thickness over time because of physiological changes. However, the dimensional changes of the buccal bone in an edentulous maxilla with an implant-supported fixed dental prosthesis are unknown. PURPOSE: The purpose of this retrospective clinical study was to evaluate cone beam computed tomography (CBCT) images of the dimensional changes of the buccal bone in edentulous maxillae with complete arch telescopic-retained implant-supported fixed dental prostheses (CTI-FDPs) after 6 years by using a professional retrieval system. MATERIAL AND METHODS: This study included 17 participants with edentulous maxillae who had been provided with CTI-FDP with 121 taper joint implants. A three-dimensional radiographic analysis by using CBCT was performed at implant insertion (0 years) and after 6 years. Vertical and horizontal bone measurement values were evaluated. During horizontal bone thickness measurement, 4 different levels, 0, 2, 4, and 6 mm apical to the implant shoulder, were evaluated as bone value (BV)0mm, BV2mm, BV4mm, and BV6mm, respectively. The BVs were compared with the Wilcoxon signed-rank test and Kruskal-Wallis test (α=.05). In addition, the Spearman rank correlation coefficient was used to identify 0yBV factors that influence the 6yBVs. A nonlinear regression analysis was used to clarify the slopes of 0yBVs and 6yBV0mm. RESULTS: Significant decreases in vertical and horizontal BVs were found between 0 years and 6 years (P<.05). However, no significant difference was observed in bone loss at 6 years at any of the vertical and horizontal measurement points (P≥.05). When 0yBVs related to 6yBV0mm were analyzed, 0yBV0mm and 0yBV2mm showed strong correlations with 6yBV0mm (|r|≥.7). In the regression analysis, a 0yBV0mm of 0.58 mm and 0yBV2mm of 0.78 mm could be critical factors associated with a 6yBV0mm of 0 mm. A 6yBV0mm of 0yBV0mm more than 0.58 mm was significantly higher than a 6yBV0mm of 0yBV0mm less than 0.58 mm (P<.001). Moreover, a 6yBV0mm of 0yBV2mm more than 0.78 mm was significantly higher than a 6yBV0mm of 0yBV2mm less than 0.78 mm (P<.001). CONCLUSIONS: The buccal bone in an edentulous maxilla with fixed implant-supported prostheses lost significant vertical and horizontal bone thicknesses after 6 years. At implant insertion, both a 0.58-mm buccal bone on the platform and a 0.78-mm buccal bone at 2 mm apical to the implant shoulder are necessary for longer term maintenance of bone on the platform of implants specifically supporting CTI-FDPs.

Overcoming Complications with Implants in the Esthetic Zone: An Innovative Approach.

Owing to the satisfactory esthetic and functional outcomes of implant surgery for the anterior teeth, some dentists consider it the gold standard treatment. However, the risk of developing peri-implantitis is positively associated with the long-term use of the implant. This necessitates the development of an implant design that reduces the risk of peri-implantitis, especially considering the long-term use of implants in young patients. This case report describes a new approach for an implant surgery using a two-stage implant in a 28-year-old woman. Her clinical course was satisfactory during the 4-year postoperative follow-up period; no inflammation was noted in the surrounding tissues. The two-stage implants allow for the removal of an implant body from an infected area and its replacement with a new abutment if peri-implantitis develops in the future.

Implant Treatment in Patient with Periodontitis: A Case Report with 13-year Follow-up.

This report describes long-term implant treatment in a patient with chronic periodontitis. The patient was a 59-year-old man who attended our facility requesting a dental implant. An initial examination revealed generalized gingival inflammation and subgingival calculus. Clinical examination revealed 55.3% of sites with a probing depth (PD) of >4 mm and 41.3% of sites with bleeding on probing. Radiographic examination revealed vertical bone resorption in #23, #33, #33, #35, and #47. Initial periodontal therapy consisting of plaque control, scaling and root planing, and tooth extraction was subsequently performed based on a clinical diagnosis of severe chronic periodontitis. Open flap debridement was performed for teeth with a PD >5 mm (#21, #22, #23, 333, #34, #35 and #47). After confirming the stability of the periodontal tissue, 3 implants were first placed in the maxilla (#25, #26, and #27). Final prostheses comprising a screw retaining-type implant superstructure were then placed (#25, #26, and 327). Following reevaluation, the patient was placed on supportive periodontal therapy. At 15 years after the first visit, the periodontal and implant conditions have remained stable. These results indicate that periodontal treatment before implantation and subsequent maintenance yield a clinically favorable and long-lasting outcome.

Marginal bone loss and the risk indicators of fixed screw-retained implant-supported prostheses and fixed telescopic-retained implant-supported prostheses in full arch: A retrospective case-control study.

OBJECTIVES: This study compared full-arch screw-retained implant-supported fixed dental prostheses (FSI-FDPs) and full-arch telescopic-retained implant-supported fixed dental prostheses with a professional retrieval system (FTI-FDPs) on marginal bone loss (MBL), the risk indicators and peri-implantitis rate after 7-13 years. MATERIAL AND METHODS: Sixty five edentulous patients were treated with 86 prostheses and 592 implants. The FSI-FDP group comprised 26 patients (32 prostheses, 202 implants), and the FTI-FDP group comprised 39 patients (54 prostheses, 390 implants). MBL and the risk indicators of MBL ≥1 mm were assessed. Peri-implantitis rates at 13 years were also calculated. RESULTS: Full-arch screw-retained implant-supported fixed dental prostheses and FTI-FDP implants exhibited comparable mean MBLs of 0.60 ± 0.51 and 0.41 ± 1.03 mm, respectively. MBL ≥1 mm was noted for 25% of FSI-FDP implants and 6.9% of FTI-FDP implants. Superstructure-abutment connection (screw retention:FSI-FDPs >telescopic retention:FTI-FDPs) and implant-abutment connection (External butt joint, Internal butt joint >Morse taper joint) were associated with MBL ≥1 mm. Peri-implantitis rates at the implant level were 3.99% (95%CI = 3.93-20.5) in FSI-FDP group and 3.85% (95%CI = 3.85-34.3) in FTI-FDP group with no significance. CONCLUSIONS: It was concluded that FSI-FDP and FTI-FDP implants exhibited comparable MBL; however, the risk of MBL ≥1 mm in FTI-FDPs was lower than in FSI-FDPs. Besides, implant-abutment connection was the risk indicator of MBL ≥1 mm. In peri-implantitis rate, FSI-FDPs and FTI-FDPs behave similarly.

Implant Body Displacement into Medullary Cavity of Mandible: A Case Report.

One serious complication in implant surgery is displacement of the implant body into the surrounding tissue. This occurs only rarely in the mandible, however. This report describes a case of an implant body displacing into the medullary cavity of the mandible and discusses this in reference to the literature. The patient was a 72-year-old woman who was referred to our department at Tokyo Dental College Chiba Hospital (now Chiba Dental Center) by her regular dentist after an implant inserted in the left mandible in 2010 showed loosening in October 2016. Panoramic X-rays obtained at the initial examination revealed that 2 implants had been inserted into the left mandible, one on top of the other. Removal of both was recommended to prevent infection at the implant site and any potential effects on the alveolar nerve. In the absence of subjective symptoms other than implant loosening, however, the patient did not consent to this proposal. Therefore, only the broken abutment was removed. The patient was instructed to contact us immediately should infection or any other symptoms appear once the mucosa had healed, and the dental clinic that had referred her to us was requested to make her a set of dentures. To our knowledge, only 11 reports have been published to date describing displacement of an implant body into the mandible, and these address a total of just 20 cases. The possibility that an implant body in the mandible may become displaced must be kept in mind during treatment.

Differences in Elderly and Non-Elderly Outpatient Subjective Evaluation of "Easy-to-Eat Meals" after Dental Treatment.

Dental treatment improves the experience of eating by healing illnesses in the oral cavity or through the installation of special devices. However, mastication can often prove difficult for short periods of time after dental treatment, potentially limiting the types of food that can be consumed. Therefore, we proposed a highly nutritious meal strategy for dental outpatients (hereafter, "easy-to-eat meals"). We previously reported patients' subjective assessment of these easy-to-eat meals as determined through a questionnaire survey. The purpose of the present study was to investigate how differences in age affected such assessments. The study participants comprised patients scheduled to undergo dental treatment. They were divided into 2 groups: one of patients aged above and one of those aged below 70 years. All were required to consume provided easy-to-eat meals at the dental hospital directly after treatment and then answer a questionnaire. The questionnaire included items on patient satisfaction with the meals, taste, portion size, convenience, reduction in discomfort, and whether they would consume them again. The format of the questionnaire was a visual analog scale (VAS), ranging from 0 (negative) to 10 (positive). Portion size was to be rated on a scale from 0 ("Not enough") to 10 ("Too much"), with 5 being "Just right". Correlations between the questionnaire items were investigated to determine how they influenced each other. The VAS average for "Reduction in discomfort" was 8.45±1.39 in the non-elderly group and 6.07±2.92 in the elderly group, and the difference was significant (p=0.02); the VAS average for "Taste" was 6.49±2.32 in the non-elderly group and 4.91±0.98 in the elderly group, and the difference was significant (p=0.04). The results of this study suggest that providing such meal plans as nutritional guidance after dental treatment can influence quality of life in elderly patients.

Clinical evaluation of full-arch screw-retained implant-supported fixed prostheses and full-arch telescopic-retained implant-supported fixed prostheses: A 5-12 year follow-up retrospective study.

OBJECTIVE: To assess the prostheses and implants survival rate and peri-implantitis rate in edentulous patients treated with full-arch screw-retained implant-supported fixed dental prostheses (FSIFDPs) and full-arch telescopic-retained implant-supported fixed dental prostheses (FTIFDPs) over an observation period of at least 5 years. MATERIALS AND METHODS: From 2004 to 2012, 696 implants were inserted into 78 patients with 102 prostheses. The FSIFDP group comprised 31 patients (37 prostheses, 232 implants), whereas the FTIFDP group comprised 47 patients (65 prostheses, 464 implants). Prosthesis and implant estimated cumulative survival rates (ECSR) and estimated cumulative peri-implantitis rates (ECPR) were assessed. The follow-up period was 5-12 years. Kaplan-Meier survival curves with the log-rank test were used to evaluate outcomes. RESULTS: The 12-year prosthesis ECSR was 96.8% (95% CI: 79.2-99.5, 36/37 prostheses) in the FSIFDP group and 96.4% (95% CI: 86.3-99.1, 63/65 prostheses) in the FTIFDP group, whereas the 12-year implant ECSR was 99.5% (95% CI: 96.4-99.9, 231/232 implants) in the FSIFDP group and 98.7% (95% CI: 96.9-99.5, 459/464 implants) in the FTIFDP group. The 12-year ECPR at the prosthesis level was 12.8% (95% CI: 12.7-47.6, 4/37 prostheses) in the FSIFDP group and 12.8% (95% CI: 11.4-24.1, 6/65 prostheses) in the FTIFDP group. The 12-year ECPR at the implant level was 4.4% (95% CI: 4.3-23.0, 6/232 implants) in the FSIFDP group and 2.2% (95% CI: 2.0-12.3, 7/464 implants) in the FTIFDP group. CONCLUSION: FTIFDPs have clinical results comparable to those of FSIFDPs. Therefore, FTIFDPs can be useful.

Applying intraoral scanner to residual ridge in edentulous regions: in vitro evaluation of inter-operator validity to confirm trueness.

BACKGROUND: The purpose of this study was to investigate the trueness of intraoral scanning of residual ridge in edentulous regions during in vitro evaluation of inter-operator validity. METHODS: Both edentulous maxillary and partially edentulous mandibular models were selected as a simulation model. As reference data, scanning of two models was performed using a dental laboratory scanner (D900, 3Shape A/S). Five dentists used an intraoral scanner (TRIOS 2, 3Shape A/S) five times to capture intraoral scanner data, and the "zig-zag" scanning technique was used. They did not have experience with using intraoral scanners in clinical treatment. The intraoral scanner data was overlapped with the reference data (Dental System, 3Shape A/S). Regarding differences that occurred between the reference and intraoral scanner data, the vertical maximum distance of the difference and the integral value obtained by integrating the total distance were analyzed. RESULTS: In terms of the maximum distances of the difference on the maxillary model, the means of five operators were as follows: premolar region, 0.30 mm; molar region, 0.18 mm; and midline region, 0.18 mm. The integral values were as follows: premolar region, 4.17 mm2; molar region, 6.82 mm2; and midline region, 4.70 mm2. Significant inter-operator differences were observed with regard to the integral values of the distance in the premolar and midline regions and with regard to the maximum distance in the premolar region, respectively. The maximum distances of the difference in the free end saddles on mandibular model were as follows: right side, 0.05 mm; and left side, 0.08 mm. The areas were as follows: right side, 0.78 mm2; and left side, 1.60 mm2. No significant inter-operator differences were observed in either region. CONCLUSIONS: The present study demonstrated satisfactory trueness of intraoral scanning of the residual ridge in edentulous regions during in vitro evaluation of inter-operator validity.

Full-Arch Implant-Supported Fixed Dental Prosthesis Retained by a Combination of Galvano-Telescopic Copings and Screws: A Clinical Report.

Full-arch screw-retained implant-supported fixed dental prostheses have a high long-term success rate and are considered the gold standard by many clinicians. However, accurate fabrication of a passive fit long-span prosthesis can be challenging. A novel intraoral adhesion method using galvano-telescopic copings was proposed as a way of improving prosthetic fit for edentulous patients. This report describes the treatment of a 74-year-old female with a full-arch implant-supported dental prosthesis, supported by a combination of galvano-telescopic copings and screws to prevent retention loss. Four years have passed since this superstructure was placed, during this time she exhibited a good clinical course with no inflammation noted in surrounding tissues. Treatment with an implant-supported fixed dental prosthesis, retained by a combination of galvano-telescopic copings and screws, can be a useful alternative treatment for edentulous patients.

Role of Dental Implant Superstructure in Patients with Severe Periodontal Disease.

Many studies have investigated the relationship between periodontal disease and the onset of peri-implantitis. It is important to devise practical measures for preventing the development of peri-implantitis in patients with periodontal disease if the success of implant treatment is to be secured. Here, we report the role of the superstructure in two cases of implant treatment in patients with severe periodontal disease. Both patients had severe periodontitis and underwent implant treatment after improving the state of the disease, thereby ensuring that the implant superstructure could be maintained. Both cases remained stable after implant treatment. The results indicate that proper periodontal treatment prior to implant treatment leads to long-term success. In addition, it is necessary to use an implant superstructure that reduces plaque accumulation in preventing peri-implantitis.

"Easy-to-eat Meals" for Outpatients Following Dental Treatment.

Patients often experience temporary difficulty in masticating during the period immediately following dental treatment. The purpose of this study was to investigate subjectively assessed satisfaction with a specially designed diet for such patients by means of a questionnaire. These "easy-to-eat meals" were planned and provided by this hospital in Japan, and comprised a combination of commercially available and nutritionally rich soft foods, jellied foods, drinks, and other items. The patients were required to commence consuming them immediately following dental treatment. The questionnaire contained 6 categories -Satisfaction, Taste, Meal completion, Convenience, Reduction in discomfort, and Likelihood of reuse - to be evaluated on a 10-cm visual analog scale (VAS). The overall response was positive in all 41 completed questionnaires, with an overall score of 6 or higher for every category. Orthodontics achieved the highest VAS score in every category, followed by oral implantology, prosthodontics, and conservative Original Article doi:10.2209/tdcpublication.2018-0055 dentistry. A correlation was observed between Satisfaction and each of the 5 remaining questionnaire categories (Taste: |r|=0.70, p≤0.00; Meal completion: |r|=0.60, p≤0.00; Convenience: |r|=0.56, p≤0.00; Reduction in discomfort: |r|=0.48, p=0.00; and Likelihood of reuse: |r|=0.79, p≤0.00). An acceptable level of convenience was obtained with these meals, as they were reported to be useful during the period immediately following treatment, when eating out or preparing meals was physically and/or psychologically difficult.

Preferential capture of EpCAM-expressing extracellular vesicles on solid surfaces coated with an aptamer-conjugated zwitterionic polymer.

Extracellular vesicles (EVs) collectively represent small vesicles that are secreted from cells and carry biomolecules (e.g., miRNA, lncRNA, mRNA, proteins, lipids, metabolites, etc.) that originate in those cells. Body fluids, such as blood and saliva, include large numbers of EVs, making them potentially a rich source of diagnostic information. However, these EVs are mixtures of vesicles released from diseased tissues as well as from normal cells. This heterogeneous nature therefore blurs the clinical information obtainable from EV-based diagnosis. Here, we synthesized an EpCAM-affinity coating agent, which consists of a peptide aptamer for EpCAM and a zwitterionic MPC polymer, and have shown that this conjugate endowed the surfaces of inorganic materials with the preferential affinity to EpCAM-expressing EVs. This coating agent, designated as EpiVeta, could be useful as a coating for various diagnostic devices to allow concentration of cancer-related EVs from heterogeneous EV mixtures.

Implant-supported Prostheses in Patient with Sjögren's Syndrome: Clinical Report with 3-year Follow-up.

Sjögren's syndrome (SS), an autoimmune disorder, affects the exocrine glands, including the lacrimal and salivary glands. It is characterized by symptoms of dry eye and dry mouth. As secretion of saliva decreases, patients with SS experience rampant caries, pain in the oral mucosa, inflammation and hardening of the salivary glands, abnormal taste, dysphagia, and loss of teeth earlier than healthy individuals. A removable partial denture is often used as a prosthesis after tooth loss. Compromised salivary lubrication, however, can produce traumatic ulceration of the mucosa, making use of a removable prosthesis in SS patients painful. In such cases, a dental implant is likely to be requested as an alternative. This report describes dental implant treatment in an SS patient, a 50-year-old woman who presented with the chief complaint of masticatory dysfunction and pain due to a removable partial denture. Eight implants were placed in the maxillary and mandibular first molar tooth and second molar tooth regions. Following a 4-month non-loading period, second-stage surgery and provisional restoration with a screwretained implant temporary crown were performed. Screw-retained superstructures were fitted by means of a customized titanium abutment and zirconia crown as the final restoration. No complications, including inflammation of peri-implant soft tissue or resorption of peri-implant bone, were observed at 3 years following placement of the superstructures.

Dental Implant Treatment with Computer-assisted Surgery for Bilateral Agenesis of Maxillary Lateral Incisors: A Case Report.

Here, we report a case of dental implant treatment involving computer-assisted surgery for bilateral agenesis of the maxillary lateral incisors. The patient was a 39-year-old woman with the chief complaint of functional and esthetic disturbance due to maxillary and mandibular malocclusion. The treatment plan comprised non-extraction comprehensive orthodontic treatment and prosthodontic treatment for space due to the absence of bilateral maxillary lateral incisors. A preliminary examination revealed that the mesiodistal spaces left by the absent bilateral maxillary lateral incisors were too narrow for implant placement (right, 5.49 mm; left, 5.51 mm). Additional orthodontic treatment increased these spaces to approximately 6 mm, the minimum required for implant placement if risk of damage to the adjacent teeth due to inaccuracies in directionality of drilling is to be avoided. For dental implant treatment with computer-assisted surgery, preoperative planning/simulation was performed using Simplant® ver.12 software and a toothsupported surgical template fabricated using stereolithography. Two narrow-diameter implants were placed in a two-stage procedure. It was confirmed that there was sufficient distance between the implant fixtures and the roots of the adjacent teeth, together with no exposure of alveolar bone. Following a 4-month non-loading period, second-stage surgery and provisional restoration with a temporary screw-retained implant crown were performed. Cement-retained superstructures made of customized zirconia abutment and a zirconia-bonded ceramic crown were fitted as the final restoration. At 5 years after implant surgery, there were no complications, including inflammation of the peri-implant soft tissue and resorption of peri-implant bone. Computer-assisted implant surgery is useful in avoiding complications in bilateral agenesis of the maxillary lateral incisors when only a narrow mesiodistal space is available for implant placement.

Implant Treatment after Sagittal Splitting Ramus Osteotomy and Alveolar Ridge Augmentation in Patient with Mandibular Prognathism and Multiple Missing Maxillary Teeth.

An abnormal maxillomandibular ridge relationship frequently hinders oral implant treatment in patients with jaw deformities. Here, we describe a patient who was experiencing difficulty using dentures due to multiple maxillary tooth loss and mandibular prognathism. Treatment comprising sagittal splitting ramus osteotomy and alveolar ridge augmentation using bone grafts harvested from the mandibular ramus followed by implant treatment yielded good outcomes. The patient was a 47-year-old woman presenting with an unstable upper partial denture. Although prior prosthetic treatment for mandibular prognathism had resulted in normal overbite, she had since lost an increasing number of teeth due to advanced periodontal disease, impairing support for the denture. She was referred to the Department of Oral Implantology at the Tokyo Dental College Chiba Hospital in October 2008. Subsequent treatment comprised implant treatment following maxillary alveolar ridge augmentation and sagittal splitting ramus osteotomy to correct the maxillary-mandibular relationship. In January 2010, sagittal splitting ramus osteotomy and alveolar bone augmentation using a bone graft from the mandibular ramus were performed under general anesthesia. In July and August 2010, a total of 7 implants were placed in the maxilla and implant superstructure preparation started after 3 months. Taking both the patient's wishes and ease of maintenance into account, retrievable superstructures made of Auro Galvano Crown were fitted in April 2011. The jaw-to-jaw alveolar ridge relationship was improved by sagittal splitting ramus osteotomy, rendering subsequent treatment, from implant placement to superstructure preparation, feasible by conventional methods. The use of surplus bone generated during sagittal splitting ramus osteotomy for bone augmentation avoided the need to harvest bone from another area.

Two-year Survey of Trends at Food Introduction Booth at Suidobashi Hospital of Tokyo Dental College.

A working group established at Tokyo Dental College Suidobashi Hospital considered how to manage patients experiencing difficulties with food intake during the process of dental treatment. This resulted in the opening of an in-hospital booth dedicated to providing advice on such problems. A survey was performed to determine the number of patients utilizing this facility and the department which they were attending with the aim of investigating factors involved in eating-related problems. The results revealed that patients were being referred to the booth from the departments of dental prosthetics, conservative dentistry, oral and maxillofacial surgery (by both dentists and dietitians), oral implantation, and orthodontics. Patients were provided with information on the booth by their dentist or dietician, either by means of introductory materials or verbally. These patients were requested to complete a questionnaire, with informed consent, over a 2-year period. The participants were classified according to age and original dental problem on attending this hospital and the results analyzed. The inability to eat hard foodstuffs, difficulty in chewing, inability to open the mouth, insufficient nutrition, unbalanced nutrition, intraoral pain, and difficulty in swallowing were all identified as problems related to eating. A total of 1,948, 413 visitors had received introductory materials, while 156 had learned of the facility verbally. Looking at department as a factor, the inability to eat hard foodstuffs and difficulty chewing occupied a large percentage of the reported problems for all departments. Taken together, these results revealed that many patients experienced difficulties in eating during the process of treatment. This indicates that it is necessary to give the appropriate eating instructions to each patient according to their specific needs and stage of dental treatment.

The genes Scgb1a1, Lpo and Gbp2 characteristically expressed in peri-implant epithelium of rats.

OBJECTIVES: The peri-implant epithelium (PIE) plays an important role in the prevention against initial stage of inflammation. To minimize the risk of peri-implantitis, it is necessary to understand the biological characteristics of the PIE. The aim of this study was to investigate the characteristic gene expression profile of PIE as compared to junctional epithelium (JE) using laser microdissection and microarray analysis. METHODS: Left upper first molars of 4-week-old rat were extracted, and titanium alloy implants were placed. Four weeks after surgery, samples were harvested by laser microdissection, and total RNA samples were isolated. Comprehensive analyses of genes expressed in the JE and PIE were performed using microarray analysis. Confirmation of the differential expression of selected genes was performed by quantitative real-time polymerase chain reaction and immunohistochemistry. RESULTS: The microarray analysis showed that 712 genes were more than twofold change upregulated in the PIE compared with the JE. Genes Scgb1a1 were significantly upregulated more than 19.1-fold, Lpo more than 19.0-fold, and Gbp2 more than 8.9-fold, in the PIE (P < 0.01). Immunohistochemical localization of SCGB1A1, LPO, and GBP2 was observed in PIE. CONCLUSION: The present results suggested that genes Scgb1a1, Lpo, and Gbp2 are characteristically expressed in the PIE.

A Case of Simultaneous Ectopic Tooth Extraction and Removal of Migrated Dental Implant from Maxillary Sinus.

When a dental implant migrates to the maxillary sinus it should be extracted immediately as it may cause sinusitis or further migrate to one of the other paranasal sinuses. Although usually detected due to symptoms such as nasal obstruction, nasal discharge, and nasal bleeding, an ectopic tooth in the maxillary sinus can sometimes be revealed incidentally on radiographic examination. Here, we report a case of simultaneous extraction of a dental implant that had migrated to the maxillary sinus and removal of an ectopic tooth that had arisen in the same location. The patient was a 73-year-old man who had received the implant to replace the first left maxillary molar at a local dental office. The implant had subsequently migrated to the left maxillary sinus and the patient was referred to us for its removal. On locating the implant on a CT scan at our hospital, an ectopic tooth was also observed at the base of the maxillary sinus. With patient consent, the decision was made to remove the ectopic tooth and extract the implant simultaneously. Excision of the lateral wall of the maxillary sinus allowed easy extraction of the implant. The ectopic tooth was removed by slightly expanding a fenestration in the sinus wall. Ectopic teeth in the maxillary sinus are sometimes put on follow-up if asymptomatic. Removal should be considered, however, if there is a risk of it becoming infected due to implantation-induced inflammation.

Current State of Undergraduate Education in Oral Implantology in Japan.

An anonymous questionnaire-based survey was used to determine the current state of and issues involved in undergraduate education in oral implantology at Tokyo Dental College. The participants comprised 139 students who had received lectures on and practical training in oral implantology in 2013. The results indicate that the overall level of student comprehension was high for both lectures and practical training content; the level of difficulty was appropriate for practical training, but the amount of practice time given requires reconsideration. Over 80% of the students gave positive responses in their overall evaluation of lectures and practical training, and the number of students who had an interest in oral implantology after finishing the course and who wanted to be involved in oral implantology as dentists increased. These results indicate that this undergraduate education program is effective in improving understanding of oral implantology. Improvement is required, however, in lecture methodology and practical training content. It is also suggested that the curriculum should be evaluated by students regularly and that the courses be subject to updating as required.