The aim of this study was to analyze orthodontic data to investigate occlusal conditions, the relationship between malocclusion and the number of congenitally missing teeth, and occlusal support of maxillomandibular teeth in patients with oligodontia. The study included 66 patients with permanent dentition from two orthodontic clinics belonging to Tokyo Dental College who had received a diagnosis of oligodontia between 2003 and 2014. The materials used for the analysis comprised intraoral photographs, panoramic radiographs, and lateral cephalometric radiographs. The antero-posterior occlusal relationships, assessed by overjet, showed a high prevalence of anterior crossbite, while the vertical occlusal relationships, evaluated by overbite, indicated a predominance of deep bite. There were no significant differences in the total number of missing teeth in the three groups divided according to degree of overjet. The same tendency was observed in the case of overbite. The number of missing teeth in the maxilla was significantly higher than that in the mandible. The high occurrence of anterior crossbite in oligodontia is believed to be related to skeletal factors, such as deficiency of the maxillary apical base and a greater number of missing teeth in the maxilla compared to in the mandible. Based on their Eichner Index scores, 98.5% of cases were classified as Class B. Among these, B2 was the most prevalent (60.6%), suggesting that patients with oligodontia have low occlusal support. The average number of Occlusal Units (OUs) was 6.4 out of 12. Nearly half of the second deciduous molars were retained in both the maxilla and the mandible. When deciduous molars were treated as premolars, there was a significant increase in number of OUs. No significant differences were observed in the actual occlusal support score, however. Therefore, oligodontia with many defects in the premolar region resulted in a low level of occlusal support, and although the survival rate of the deciduous molars was high, they were not useful in providing occlusal support.

The epithelial cell rests of Malassez (ERM) are located within the periodontal ligament. They are reportedly involved in maintaining homeostasis, particularly with regards to the thickness of the periodontal ligament. Their role in apical periodontitis lesions remains unclear, however. This study investigated the response of ERM to infection with Porphyromonas gingivalis. After being infected, the morphology of the P. gingivalis-infected cells was observed using confocal laser-scanning microscopy. The gene expression of P. gingivalis-infected and uninfected cells was investigated by RNA-sequencing analysis. Morphological observation showed the invasion and adhesion of P. gingivalis to the surface of ERM. The RNA analysis showed that the gene expression profile significantly differed between the infected and uninfected cells. At an expression level of ≥2 and false discovery rate of <0.1, the infected cells showed a decrease in 99 genes and an increase in 6 compared with in the non-infected cells. Most of the upregulated genes were unique to epithelial cells, such as endothelial cell-specific molecules and cytokeratin 5; the upregulated genes were associated with the immune response, however. These results indicate that ERM upregulate genes associated with epithelial cells and suppress those associated with the immune response following P. gingivalis infection.

Various pieces of information, including the age of the patient, the site involved, symptoms, intraoral findings, and X-ray findings are necessary in making a clinical diagnosis. This report describes a case in which the initial diagnosis was eruption sequestrum based on clinical information but which was later found to be a complex odontoma based on histopathological findings. The patient was an 8-year-old girl who presented at our hospital with the chief complaint of pain in the right mandibular molar region. The distal aspect of the right mandibular first molar, which had partially erupted, was covered with gingiva and hard tissue which were separated from the tooth itself. X-ray findings showing radiopaque hard tissue at this site indicated a clinical diagnosis of eruption sequestrum. After local infiltration anesthesia, the hard tissue was extracted and a gingivectomy performed. Histopathological examination of the excised material, however, indicated a diagnosis of complex odontoma.

This report describes a case of generalized aggressive periodontitis requiring periodontal treatment including regenerative therapy. The patient was a 34-year-old woman who visited the Tokyo Dental College Suidobashi Hospital with the chief complaint of pain in tooth #14. An initial examination revealed that 35.8% of sites had a probing depth of ≥4 mm, while 19.1% showed bleeding on probing. Radiographic examination revealed angular bone resorption in #14, 33, 36, and 46, with horizontal resorption in other areas. Based on a clinical diagnosis of Stage III Grade C periodontitis, initial periodontal therapy consisting of plaque control, and scaling and root planing was performed. After reevaluation, periodontal regenerative therapy using recombinant human fibroblast growth factor-2 (rhFGF-2) in combination with carbonate apatite (CO₃Ap) granules was performed for #14 and 33, while regenerative therapy using rhFGF-2 alone was performed for #46. Following reevaluation, the patient was placed on supportive periodontal therapy (SPT). During SPT, CAD/CAM crowns were placed on #26 and 46. Periodontal regenerative therapy using rhFGF-2 with CO₃Ap granules yielded a resolution of angular bone defects in #14 and 33. This improvement has been adequately maintained over a 30-month period.

Treponema denticola is frequently isolated together with Porphyromonas gingivalis from the lesions seen in cases of chronic periodontitis and is considered a major pathogen of this disease. It has several virulence factors, including a major surface protein (Msp) and a major surface protease, dentilisin. The effect of these virulence factors on the host immune response remains to be elucidated, however. Toll-like receptors (TLRs) in the host can recognize pathogen-associated molecular patterns. Bacteria stimulate TLRs and activate the pro-inflammatory nuclear factor-kappa B pathway. Therefore, the aim of this study was to investigate the effect of T. denticola on TLR pathways. Toll-like receptor 4 and TLR2 reporter cell lines, which secrete alkaline phosphatase in response to TLR signals, were infected with the T. denticola wild type, an Msp-deficient mutant, a dentilisin-deficient mutant, or their extracts obtained via sonication. Signals from TLR2 or TLR4 cells were evaluated by alkaline phosphatase activity. Toll-like receptor 2 signals were detected in all T. denticola strains and sonication extracts, while no TLR4 signal was detected. Infection with the dentilisin-deficient mutant induced the strongest TLR2 signal among the strains. Sonication extracts of the wild type and Msp-deficient mutant showed the same level of TLR2 signaling. The TLR2 signal in the sonication extracts from the wild type was inhibited by Sparstolonin B, an antagonist of TLR2, in a dose-dependent manner. These results indicate that T. denticola is recognized by epithelial cells mainly via TLR2. The outer sheath structure may conceal potential ligands for TLR2.