We investigated the associations of mouthguard awareness and use with the rate and type of orofacial trauma during sports activities among professional athletes. In this cross-sectional study of athletes aged 12 to 22 years who trained for participation in national and international competitions, data were collected by using a questionnaire and a clinical examination that included an index of dental injury. There were significant differences in mouthguard awareness and use and injury rates, i.e., athletes who did not wear mouthguards had more injuries. Traumatic injuries to teeth were significantly more frequent among contact athletes (15; 9%) than among noncontact athletes (4; 2.5%). Limited mouthguard awareness could be due to lack of information and education on dental injuries and their prevention. (J Oral Sci 56, 239-243, 2014)

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We investigated the effects of triple antibiotic paste (TAP) and modified triple antibiotic paste (MTAP) concentrations on the microhardness and chemical structure of radicular dentine. Human root cylinders were instrumented and randomized into four treatment groups and an untreated control group. Two treatment groups received 1 g/mL TAP or MTAP, and the other two treatment groups received 1 mg/mL methylcellulose-based TAP or MTAP. Cylinders were stored at 100% relative humidity for 4 weeks. Each root cylinder was subjected to a microhardness test before and after treatment. Different sets of radicular dentine specimens were treated as mentioned previously, and were examined using attenuated total reflection Fourier transform infrared spectroscopy. All treatment groups showed significant reductions in microhardness of roots when compared to untreated control roots at 1,000 and/or 500 µm from the pulp-dentine interface. However, 1 mg/mL methylcellulose-based antibiotics caused significantly less reduction in microhardness when compared to 1 g/mL antibiotics. In addition, 1 g/mL TAP and DAP caused significantly lower phosphate/amide I ratios when compared to other groups. The use of 1 mg/mL methylcellulose-based TAP and MTAP may minimize the reduction in microhardness of roots compared with the currently used 1 g/mL concentration of these antibiotics. (J Oral Sci 56, 245-251, 2014)

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Periodontitis is a chronic inflammatory disease caused by specific bacteria and viruses. Local, systemic, and environmental factors affect the rate of disease progression. Immune responses to bacterial products, and the subsequent production of inflammatory cytokines, are crucial in the destruction of periodontal tissue. MicroRNAs (miRNAs) are a class of small RNAs that control various cell processes by negatively regulating protein-coding genes. In this study, we compared miRNA expression in inflamed and noninflamed gingival tissues from Japanese dental patients. Total RNAs were isolated from inflamed and noninflamed gingival tissues. miRNA expression profiles were examined by an miRNA microarray, and the data were analyzed by GeneSpring GX, Ingenuity Pathways Analysis, and the TargetScan databases. Observed miRNA expression levels in inflamed gingiva were confirmed by real-time PCR. The three most overexpressed (by >2.72-fold) miRNAs were hsa-miR-150, hsa-miR-223, and hsa-miR-200b, and the three most underexpressed (by <0.39-fold) miRNAs were hsa-miR-379, hsa-miR-199a-5p, and hsa-miR-214. In IPA analysis, hsa-miR-150, hsa-miR-223, and hsa-miR-200b were associated with inflammatory disease, organismal injury, abnormalities, urological disease, and cancer. The present findings suggest that miRNAs are associated with chronic periodontitis lesions in Japanese. (J Oral Sci 56, 253-260, 2014)

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Amelotin (AMTN) is a secreted protein transcribed predominantly during the maturation stage of enamel formation and localized in the junctional epithelium. We investigated differences in the levels of AMTN gene expression between non-inflamed gingiva and inflamed gingiva from patients with chronic periodontitis. Total RNAs were isolated from these tissues and their gene expression profiles were monitored by DNA microarray. The observed induction of AMTN mRNA in inflamed gingiva and cultured human gingival fibroblasts (HGF) was confirmed by real-time PCR. Transient transfection assays were performed using chimeric constructs of mouse AMTN gene promoter fragments linked to a luciferase reporter gene. Immunohistochemical localization of AMTN in inflamed and non-inflamed gingiva was assessed by immunohistochemistry. Among many differentially expressed genes, the level of AMTN mRNA was significantly increased in inflamed gingiva. Treatment of HGF with interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) induced the expression of AMTN mRNA, and increased the luciferase activities of the AMTN promoter constructs. AMTN protein was detected in inflamed gingival connective tissue and junctional epithelium. These findings demonstrate that proinflammatory cytokines induce AMTN gene expression in human gingival fibroblasts and suggest a role for AMTN in gingival inflammation. (J Oral Sci 56, 261-268, 2014)

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As compared with continuous rotary systems, reciprocating motion is believed to increase the fatigue resistance of NiTi instruments. We compared the cyclic fatigue and torsional resistance of reciprocating single-file systems and continuous rotary instrumentation systems in simulated root canals. Eighty instruments from the ProTaper Universal, WaveOne, MTwo, and Reciproc systems (n = 20) were submitted to dynamic bending testing in stainless-steel simulated curved canals. Axial displacement of the simulated canals was performed with half of the instruments (n = 10), with back-and-forth movements in a range of 1.5 mm. Time until fracture was recorded, and the number of cycles until instrument fracture was calculated. Cyclic fatigue resistance was greater for reciprocating systems than for rotary systems (P < 0.05). Instruments from the Reciproc and WaveOne systems significantly differed only when axial displacement occurred (P < 0.05). Instruments of the ProTaper Universal and MTwo systems did not significantly differ (P > 0.05). Cyclic fatigue and torsional resistance were greater for reciprocating systems than for continuous rotary systems, irrespective of axial displacement. (J Oral Sci 56, 269-275, 2014)

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Effective decontamination of root canal systems is a constant concern in clinical practice. In this article, we compare the performance of photodynamic therapy (PDT) and sodium hypochlorite (NaOCl) in reducing the amount of Enterococcus faecalis in root canals. Relevant studies were identified by searching electronic databases, including Web of Science, PubMed, BVS (Medline, Scielo, Lilacs and BBO), Scopus, and Cochrane, and by manually searching the references of identified studies. The terms used in the literature search were “photodynamic therapy” and “Enterococcus faecalis”. We selected 13 experimental studies that exclusively assessed the performance of PDT in reducing E. faecalis in root canals of human teeth. In an evaluation of methodological quality, 12 articles were classified as moderate-quality reports and 1 as a high-quality report. No article needed to be excluded because of low-quality methodology. The results showed that PDT had a better antimicrobial effect when used as an adjuvant endodontic treatment to NaOCl. However, this finding should be carefully interpreted, as there are few relevant studies and the methods of the selected studies varied. (J Oral Sci 56, 277-285, 2014)

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This study examined the influence of powder composition and morphology on the penetration of Gray and White ProRoot mineral trioxide aggregate (GMTA, WMTA) and calcium hydroxide (CH) into open dentin tubules. GMTA, WMTA, and CH particle dimensions were analyzed by flow particle image analysis (FPIA). Penetration of open dentin tubules into dentin discs was studied by scanning electron microscopy. Five samples of each material were randomly selected and prepared for this study. The GMTA averages for length (μm), width (μm), perimeter (μm), and aspect ratio were 1.94 ± 1.65, 1.43 ± 1.19, 5.61 ± 4.27, and 0.76 ± 0.14, respectively. Corresponding averages for WMTA were 2.04 ± 1.87, 1.49 ± 1.33, 5.88 ± 4.81, and 0.76 ± 0.14, and for CH were 2.26 ± 1.99, 1.62 ± 1.46, 6.70 ± 5.60, and 0.74 ± 0.15, respectively. The rank order of the averages for particle length, width and perimeter from the largest to the smallest material was CH > WMTA > GMTA. The rank order of the averaged aspect ratios was GMTA > WMTA > CH. SEM showed that all three materials, when deposited and agitated on dentin discs, penetrated the open dentin tubules. Tubule occlusion occurred as particle surface concentrations increased. Significant differences in particle length, width, perimeter, and aspect ratio were observed for GMTA, WMTA, and CH (P < 0.0001 in all cases). All particle types penetrated into open tubules when agitated on dentin discs; all tubules were eventually occluded as particle concentrations grew. (J Oral Sci 56, 287-293, 2014)

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The objectives of this study were i) to conduct a comprehensive review of the literature on hypo-hyperdontia, and ii) to categorize the reported cases based on occurrence. An extensive search of the literature covering the period from January 1966 to January 2014 was conducted using the Embase, Google Scholar, Medline, and PubMed databases. The key words used in the search strategy were “concomitant”, “agenesis”, “hypodontia”, “hyperdontia”, “supernumerary teeth”, “syndromes”, and “hypohyperdontia” in various combinations. The retrieved data were analyzed based on gender, occurrence, and occurrence of both hypodontia and hyperdontia. Descriptive statistics were carried out using the chi-squared test. For hypo-hyperdontia overall, seven case studies and 40 cases involving 103 patients were reported. Our comprehensive review revealed that hypo-hyperdontia occurs most commonly in males (P < 0.05), and the bimaxillary type (65%) was reported most commonly in comparison with the maxillary, pre-maxillary and mandibular types (P < 0.001). Twenty syndromic cases and two case studies on familial occurrence of hypohyperdontia were reported. Almost 57% of cases affected the anterior region, whereas 43% of cases affected the anteroposterior region. The anterior region was most commonly affected by hyperdontia whereas the posterior region was most commonly affected by hypodontia. Hypo-hyperdontia is commonly seen in males, and the most common type is bimaxillary occurrence. G/BBB syndrome is commonly associated with hypo-hyperdontia, being relatively frequent in the anterior region, where mesiodens is frequently seen, and second premolars are the most commonly missing teeth. (J Oral Sci 56, 295-302, 2014)

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Extreme distal migration of impacted teeth to the subcondylar area and condyle is very rare. Using an interesting sequence of radiographs showing the path of the tooth in the mandible, we describe the intrabony migration of a mandibular second premolar from angle to condyle in a young woman. Cone-beam computed tomography was used to establish the precise location of the tooth. (J Oral Sci 56, 303-306, 2014)

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Dens invaginatus is a well-recognized phenomenon, and its endodontic treatment poses a challenge, especially for peri-invagination lesions with vital pulp. Here we describe the outcome of conservative treatment and follow-up in a case of type III dens invaginatus. Cone-beam computed tomography was used for diagnosis and follow-up. Pulp vitality was preserved with endodontic treatment of only an invaginated canal. At the 24-month follow-up examination, the tooth was asymptomatic and repair of the lesion was evident radiographically. This case was managed successfully with endodontic treatment of the invagination. (J Oral Sci 56, 307-310, 2014)

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Endodontic therapy is indicated for cases of traumatic tooth dislocation associated with pulp necrosis and/or inflammatory resorption. Here we describe the management of a maxillary left lateral permanent incisor that suffered lateral luxation, leading to pulp necrosis and root resorption, in a 13-year-old boy. The traumatized tooth was treated successfully by intracanal medication with calcium hydroxide, 2% chlorhexidine gel and zinc oxide for 12 months without any need to change the dressing, followed by conventional root canal filling. The postoperative course was uneventful and a stable clinical outcome was obtained with evidence of periapical lesion repair and stabilization of the resorption process. (J Oral Sci 56, 311-314, 2014)

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Kostmann syndrome is a rare, congenital immunological disorder caused by a mutation of the hematopoietic cell-specific LYN substrate 1-associated protein X1. These patients pose a unique challenge to the dental practitioner due to the severe oral infections that are often seen in this population. The patient described in this report is a 16-year-old female with Kostmann syndrome-associated periodontitis. The treatment consisted of scaling and root planing performed in conjunction with subgingival irrigation with povidone-iodine solution. This report details how Kostmann syndrome-associated periodontitis can be successfully treated and maintained long-term, using non-surgical treatment modalities and local antimicrobial therapy. (J Oral Sci 56, 315-318, 2014)

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