Periodontitis is a common disease in adults, and its progression can cause alveolar bone resorption. Glycosphingolipids are related to bone metabolism, and miglustat, a glucosylceramide synthase (GCS) inhibitor involved in the formation of glycosphingolipids, suppresses alveolar bone resorption. In this study, the alveolar bone volume of periodontal tissues and the attachment level were evaluated. We used tartrate-resistant acid phosphatase (TRAP) staining to measure osteoclast number per bone surface (Oc.N/BS) and osteoclast surface per bone surface (Oc.S/BS). Additionally, we measured immunostaining scores and number of IL-1β- and TNF-α-positive cells in the periodontal ligament using immunostaining. Miglustat administration increased remaining alveolar bone volume and suppressed clinical attachment loss. Furthermore, osteoclast count and the expression of IL-1β and TNF-α in the periodontal tissues decreased. The results of this study indicate that miglustat may prevent periodontitis in mouse models.

Orthodontic treatment involves tooth movement through alveolar bone metabolism caused by orthodontic force. Ganglioside GD3 glycolipid is expressed in the brain, cranial nerves, and osteoclasts. Femur bone resorption was suppressed in aged GD3 synthase gene deficient (GD3S KO) mice. This study investigated the effects on alveolar bone metabolism in GD3S KO mice. Closed coiled springs were fitted into the alveolar region of maxillary anterior teeth and left first molar (M1) of GD3S KO (n=6) and wild-type mice (Wild: n=6) to apply orthodontic force and induce tooth movement. After 21 days, they were euthanized; micro-computed tomography measured the tooth-movement distance and remaining alveolar bone volume (BV/TV) of the interradicular septum of M1. Osteoblasts and osteoclasts were measured using hematoxylin-eosin and tartrate-resistant acid phosphatase staining, respectively. Sympathetic and sensory nerve activities were evaluated using immunostaining. GD3S KO mice showed a significant decrease in tooth-movement distance and increased BV/TV of interradicular septum compared with Wild. Osteoblast count was insignificant; however, significantly lower osteoclast count and sympathetic and sensory nerve activities were observed in GD3S KO mice than Wild. GD3S KO mice had decreased tooth movement and bone mass maintenance with reduced sympathetic nerve activity and nerve regeneration in the periodontal ligament.

One promising option for enhancing the growth of new bone is periosteal distraction. The objective of the present study was to develop a protocol for stable alveolar distraction. In beagles, we used a newly developed distraction device to augment the mandibular alveolar ridge. Bilateral extraction of molars and premolars was performed, followed by removal of the surrounding buccal cortical bone (thickness, 3-4 mm) to simulate atrophy. Then, we inserted a titanium screw (diameter, 0.9) beneath the periosteum for subsequent initiation of distraction. Following a 16-week healing period, three beagles were fitted with a bilateral titanium periosteal distraction device (total of six sides) and underwent lateral distraction of the periosteum (0.5 mm per day over 6 days). One dog (two sides) served as control. There were no signs of device infection or displacement. Ten weeks after the distraction, all animals were euthanized. Samples were collected and mandibles were halved. Before fixation, one side was decalcified and the other was not. All animals successfully tolerated the distraction device, which stayed securely attached to the lateral ramus of the mandible throughout the entire study period. No soft tissue dehiscence or distraction exposure occurred. Following the study period, all surgical sites exhibited healing without signs of infection. Histological analysis revealed dense bone formation with a lamellar structure: the mean increase in bone width was 0.69 ± 0.25 mm in non-decalcified specimens compared to control specimens. In conclusion, a periosteal distraction device can potentially induce bone formation, suggesting clinical applicability.

Regenerative approaches improve the results of furcation treatment; however, unpredictable periodontal regeneration is still observed in Class III furcation defects. This study assessed the effects of premolars with Class III furcations treated with porous carbonate apatite (CA) and basic fibroblast growth factor (bFGF). Class III furcations were created in the pre-molars of four beagle dogs. The teeth were randomly assigned to one of three treatment groups: Group 1 (control), treated with scaling and root planing; Group 2 (CA), the same treatment as Group 1 plus porous CA; and Group 3 (FGF + CA), the same treatment as Group 2 plus 60 μg of bFGF. After a 10-week healing period, the third and fourth lower premolars were scanned using micro-focus X-ray computed tomography (CT), followed by routine histological processing and conventional staining (hematoxylin and eosin), azan staining, and TRAP staining. Micro-CT analysis indicated better regenerative results in FGF + CA, which showed greater mineralized tissue filling of the defects in comparison to the control and CA groups. A comparison between the control and FGF + CA groups showed that the new bone area was significantly higher in the FGF + CA group (P < 0.05). After the 10-week healing period, new bone area (%) was as follows: control, 17.58±2.98%, CA, 44.66±19.52% and FGF + CA, 69.22±7.94%. These results indicate that porous CA with bFGF may enhance the regenerative results in Class III furcation lesions.

In this study, we aimed to investigate the effects of essential amino acid (EAA) deficiency on human gingival fibroblasts (HGFs). EAA deficiency inhibited HGF proliferation and migration, leading to impaired cellular functions. It also caused morphological changes, leading to thinner and less elongated cells, and suppressed collagen gene expression and synthesis. EAA deficiency promoted autophagy, as indicated by the increased expression levels of LC3 and decreased expression levels of p62. Overall, these findings suggest that EAA deficiency significantly impairs wound healing and tissue regeneration by HGFs. Therefore, adequate EAA intake is important to enhance tissue repair, particularly in periodontal treatment, by supporting the cellular functions necessary for healing.

The aim of the present study was to compare CT images between squamous cell carcinoma (SCC) and non-SCC found in the maxillary sinus, and to identify features that could be used to differentiate between SCC and non-SCC. Patients who visited the Faculty of Dentistry, Okayama University Hospital, between April 2007 and March 2023, underwent head and neck CT, and had tumors extending into the maxillary sinus that were diagnosed histopathologically as malignancy, were enrolled. The main seat of the mass, bony changes in the maxillary sinus wall, and extension into the surrounding area were assessed. These imaging features were evaluated according to SCC or non-SCC, and the characteristics of the two classes were assessed. Comparisons between the two groups were made using the Fisher exact probability test. There were 11 cases each of SCC and non-SCC. In 11 SCC and 7 non-SCC cases, the main seat of the mass occupied the entire maxillary sinus. The frequency of mass occupying the whole sinus was significantly higher in SCC than in non-SCC (p<0.05). Bone-thickening type disease was found only in squamous cell carcinoma 4/11 (36.4%), with there being a significant difference between SCC and non-SCC (p<0.05). Occupancy of the entire maxillary sinus by the mass and bone thickening on CT images were useful for differentiating between SCC and non-SCC arising in the maxillary sinus.

We aimed to compare the efficacy and complications of novel bioceramic root canal filling materials and traditional root canal filling materials in complex root canal cases. Ninety complex root canal cases treated between January 2021 and January 2023 were selected and equally allocated into a novel group and a traditional group. Novel bioceramic filling materials were used in the novel group, while traditional filling materials were utilized in the traditional group. The clinical data, imaging observations and complications were observed before treatment and during follow-up at 1, 3 and 6 months after operation. The Visual Analog Scale (VAS) pain score, swelling score, infection rate, and incidence rate of periapical lesions were significantly reduced in both groups after treatment (P<0.001). However, the novel group had significantly lower VAS pain score, swelling score, infection rate, and incidence rate of periapical lesions than those of the traditional group after treatment (P<0.05). The novel group was superior to the traditional group in terms of filling quality, root canal morphology, apical sealing, periapical inflammatory response, bone resorption in periapical lesions, and periapical healing score (P<0.05). The cases of infection, root fracture, root canal reinfection, and dislodgement of filling materials were fewer in the novel group than those in the traditional group (P<0.05). The novel bioceramic root canal filling materials have better efficacy and lower risk of complications.