A 67-year-old female patient with intellectual disability presented with a self-inflicted nasal defect and palatal perforation. In 2006, she was referred to our department by a nurse from her care facility with the chief complaint of food leakage into the nasal cavity due to the palatal perforation. Her medical history revealed a long-standing habit of scratching the nasal cavity, which had persisted for more than 30 years since approximately 27 years of age. Clinical and radiographic examinations, including three-dimensional computed tomography (3D-CT), demonstrated a nasal defect, crust formation around the nasal region, a perforation in the central palate (approximately 3 × 4 mm), and a palatal bone defect (approximately 28 × 24 mm). We selected a conservative approach using a soft palatal obturator made of ethylene-vinyl acetate (thickness: 3.0 mm) instead of surgical closure. In 2007, after several sessions of assisted feeding training with verbal encouragement, the patient accepted the use of the obturator. Although enlargement of the perforation (approximately 12 × 9 mm) was observed in 2018, her body weight increased by 4.0 kg and body mass index (BMI) improved by 3.1 compared with baseline values in 2006. In addition, no hospitalization due to aspiration pneumonia or other systemic complications occurred during the approximately 18-year follow-up period. The patient died at the age of 84 in 2024. The long-term use of a palatal obturator in a care facility setting may have contributed to improved nutritional status and reduced self-injurious behavior.

Background: The combination of polynucleotides and hyaluronic acid with bovine bone grafts in maxillary sinus lift procedures appears to be a promising strategy to enhance bone regeneration. This study aimed to analyze implant osseointegration, bone repair and sinus mucosa integrity using Bio-Oss® and Hyaluronic Acid-Polynucleotide Gel (Regenfast®) in maxillary sinus augmentation in rabbits. Methods: Sinus floor elevation was performed in 12 rabbits, with one implant placed per sinus simultaneously. In the control group, sinuses were grafted with deproteinized bovine bone mineral (Bio-Oss®) alone; in the test group, Bio-Oss® was combined with Regenfast®. Two histological slides were obtained per sinus after 2 weeks (six animals) and 10 weeks (six animals): one from the grafted area alone (non-implant sites), and one from the implant site. Primary outcome variables included the percentage of newly formed bone, the extent of implant osseointegration, and the number of sinus mucosa perforations caused by contact with graft granules. Results: After 10 weeks of healing, the test group showed a significantly higher percentage of new bone formation (37.2 ± 6.7%) compared to the control group (26.8 ± 10.0%; p = 0.031); osseointegration extended to the implant apex in both groups; fewer sinus mucosa perforations were observed in the test group (n = 5) than in the control group (n = 14). Conclusions: The addition of Regenfast® to Bio-Oss® granules promoted enhanced bone regeneration within the elevated sinus area and was associated with a lower incidence of sinus membrane perforations compared to the use of Bio-Oss® alone.

Background: Cortical and marrow bone layer have different histomorphometric features. The traditional implant insertion technique provides for fixture stabilization through the cortical area. However, this approach has been found to result in an overstress of this bone layer, which may lead to resorption. Therefore, the aim of this study was to evaluate bone healing by applying two different implant site preparation protocols across various bone densities. Materials and Methods: One implant was placed in each femur and tibia of the rabbits (four implants per animal), using two distinct site preparation methods: drilling alone or drilling followed by osteotomes (funnel technique). Three regions around the implant were evaluated: cervical, marrow, and apical. The study included 12 rabbits, divided into two groups of 6 animals each, which were euthanized at 3 and 6 weeks, respectively (n = 6 per group). Results: In the cervical region of both femur and tibia, no marginal bone resorption could be detected. Similar BIC% (bone-to-implant contact percentages) were observed for funnel and drill sites after 3 weeks and 6 weeks of healing. Differences, though not statistically significant, ranged between 2.8% and 4.7%. However, higher BIC% values were observed in the femora compared to the tibia in both periods. Conclusions: No marginal bone loss was observed in both techniques. No statistically significant differences in bone resorption or bone-to-implant contact around the implant collar were observed when comparing two implant site preparation protocols across various bone densities. The use of osteotome did not influence the healing in the marrow region.

Vertical and horizontal bone augmentation is one of the most challenging techniques in bone engineering. The use of barrier membranes and scaffolds in guided bone regeneration (GBR) procedures is a common approach for the treatment of lost bone around teeth and dental implants. The aim of this study was to estimate the barrier effects of a synthetic poly (lactic acid/caprolactone) [P(PA/CL)] bilayer membrane for GBR, compared to a porcine collagen bilayer membrane, in the vertical augmentation model on 10–12-months old rat skull without periosteum. The HAp block (diameter: 4 mm, height: 3 mm, porosity:75%, average pore size:150 μm) was placed on the rat skull without a periosteum. The P(LA/CL) membrane (solid layer: 25 μm, porous layer: 175 μm) or the collagen membrane (solid layer, porous layer) was applied onto the HAp block. At 3, 6, and 12 weeks after the surgery, the incised tissues were fixed, decalcified, and stained with hematoxylin and eosin for histological evaluation. The P(LA/CL) membrane remained until 12 weeks and could achieve barrier effects to inhibit cellular invasion from the repositioned soft tissues. Local bone formation occurred in the interconnected pores of HAp at 6 weeks. On the other hand, the collagen membrane did not inhibit cellular invasion for its expansion until 3 weeks, and was absorbed until 6 weeks. The results indicated that the P(LA/CL) membrane might be effective in GBR as occlusive absorbable membrane.

The purpose of this study is to develop two-step deep learning models that can automatically detect implant regions on panoramic radiographs and identify several types of implants. A total of 1,574 panoramic radiographs containing 3675 implants were included. The implant manufacturers were Kyocera, Dentsply Sirona, Straumann, and Nobel Biocare. Model A was created to detect oral implants and identify the manufacturers using You Only Look Once (YOLO) v7. After preparing the image patches that cropped the implant regions detected by model A, model B was created to identify the implant types per manufacturer using EfficientNet. Model A achieved very high performance, with recall of 1.000, precision of 0.979, and F1 score of 0.989. It also had accuracy, recall, precision, and F1 score of 0.98 or higher for the classification of the manufacturers. Model B had high classification metrics above 0.92, exception for Nobel’s class 2 (Parallel). In this study, two-step deep learning models were built to detect implant regions, identify four manufacturers, and identify implant types per manufacturer.

This clinical report describes immediate tooth auto-transplantation with an autograft of partially demineralized dentin/cementum matrix (pDDM), based on an orthodontic treatment plan for a 16-year-old male patient with a congenital missing tooth (#45). First, vital teeth (#14, #24) were extracted, and root canal filling (#14) was immediately performed with the support of a fixation device. Simultaneously, the tooth (#24) was crushed in an electric mill for 1 min, and the crushed granules were partially demineralized in 2% HNO3 solution for 20 min as the graft material. Next, the donor tooth was transplanted into the created socket (#45), and stabilized using an enamel bonding agent. The wet pDDM was loaded into the location of the congenital missing tooth, and the flap was repositioned. The bonding agent for stabilization was removed at 28 days, and also small contact points between the transplanted tooth and the upper premolar (#14) were added using photopolymerizable composite resin. X-ray photos were taken sequentially, and there were no postoperative complications. The radiographic images showed that the periodontal ligament space and alveolar ridge line could be observed at 18 months. The pDDM was harmonized with the mandible, and the remodeled bone-like shadow was observed in the graft region. We concluded that immediate tooth transplantation with root canal fillings and autogenous pDDM may be a valuable alternative to dental implanting or bridge formation for patients with a congenital missing tooth, followed by orthodontic treatment.

AIM:to evaluate bone formation in close contact with the sinus mucosa after different periods from sinus augmentation and the influence on healing of the presence of an inward dis-placed bone window.MATERIAL AND METHODS:Eighteen rabbits were included in the experiment. A trap-door technique was applied at the test sites, and the bony window was elevated inward (inward window; IW) together with the sinus mucosa. At the control sites, the bony window was removed before the elevation of the sinus mucosa. The elevated space was filled with deproteinized bovine bone mineral (DBBM) and both access windows were covered with a collagen membrane. Histometric measurements were performed subjacent the sinus mucosa after 2, 4, and 8 weeks of healing.RESULTS:Very few sinuses presented small percentages of new bone in close contact with the sinus mucosa in the various period examined. The presence of bone in the neighbor areas might have influenced bone formation close to the sinus mucosa. The inward displaced bone window supported bone formation close to the sinus mucosa only in the earliest period of healing, while the bone walls increased their influence over time. The lack of increased new bone percentage over time in the most central regions of the elevated sinus mucosa do not support the hypothesis that the sinus mucosa may express its potential in bone formation. It can be speculated that the new bone found in the intermediate and middle regions of the control sites in the earliest period of healing might be due to residual of bone from the osteotomy.CONCLUSIONS:Very small amounts of new bone were found subjacent to the sinus mucosa, mostly formed from the bone walls, the inward displaced bone window or from possible bone residues from the osteotomy procedures. The lack of increased new bone percentage over time in the most central regions of the elevated sinus mucosa indicates that the contribution to bone formation provided by the sinus mucosa is limited.

In this study, we compared the healing process of bone defects treated with a trephine bur with those treated with an ultrasonic knife using a critical-sized bone defect model on rat calvaria. Nine-millimeter critical-size bone defects were prepared using both instruments in the calvaria of adult Sprague-Dawley rats. One and four weeks after the osteotomy, we performed a histomorphometric analysis to evaluate bone regeneration around the cutting surface. Quantitative micro-computed tomography analyses of the bone volume in both groups suggested that ultrasonic knife surgery resulted in superior bone formation compared to that in trephine bur surgery. Furthermore, at the cutting surface, the ultrasonic knife treatment retained the alkaline phosphatase activity and new bone formation, which was identified using calcein staining, even one week after surgery. Considering the speed and volume of bone regeneration, the ultrasonic knife is likely to be the preferred over the trephine bur to perform osteotomies in implant surgery.

Background Recently, it has become possible to analyze implant placement position using the digital matching data of optical impression data of the oral cavity or plaster models with cone beam computed tomography (CBCT) data, and create a highly accurate surgical guide. It has been reported that CBCT measurements were smaller than the actual values, termed shrinkage. Matching of digital data is reliable when the plaster model or intraoral impression values show shrinkage at the same rate as the CBCT data. However, if the shrinkage rate is significantly different, the obtained digital data become unreliable. To clarify digital matching reliability, we examined dimensional reproducibility and shrinkage in measurements obtained with a model scanner, intra-oral scanner (iOS), and CBCT. Materials and methods Three implants that were arranged in a triangle were fixed in an acrylic plate. The distance between each implants were measured using model scanner, iOS, and CBCT. The actual size measured by electronic caliper was regarded as control. Results All values measured with CBCT were significantly smaller than that of model scanner, iOS, and control (p<0.001). The model scanner shrinkage was 0.37-0.39%, iOS shrinkage was 0.9-1.4%, and CBCT shrinkage was 1.8-6.9%. There were statistically significant differences among the shrinkage with iOS, CBCT, and model scanner (p<0.001). Conclusion Our findings showed that all measurements obtained with those modalities showed shrinkage as compared to the actual values. In addition, CBCT shrinkage was largest among three different measuring methods. They indicated that data matching between CBCT and scanner measurements requires attention in regard to the reliability of values obtained with those devices.

Human oral microbiome research has revealed that differences in microbial communities may lead to not only oral disease but also systemic conditions. Although large-scale cohort studies are needed to further investigate these relationships, little is known about the storage method of salivary samples collected in the clinical field. In this study, the temporal stability of salivary microbiota at room temperature was investigated to support future cohort studies of the oral microbiome.

Dental pulp stem cells (DPSCs) are mesenchymal stem cells (MSCs) that have multipotent differentiation and a self-renewal ability. They have been useful not only for dental diseases, but also for systemic diseases. Extensive studies have suggested that DPSCs are effective for various diseases, such as spinal cord injuries, Parkinson's disease, Alzheimer's disease, cerebral ischemia, myocardial infarction, muscular dystrophy, diabetes, liver diseases, eye diseases, immune diseases, and oral diseases. DPSCs have the potential for use in a cell-therapeutic paradigm shift to treat these diseases. It has also been reported that DPSCs have higher regenerative potential than the bone marrow-derived mesenchymal stem cells known as representative MSCs. Therefore, DPSCs have recently gathered much attention. In this review, the therapeutic potential of DPSCs, the latest progress in the pre-clinical study for treatment of these various systemic diseases, and the clinical applications of DPSCs in regenerative medicine, are all summarized. Although challenges, including mechanisms of the effects and establishment of cell processing and transplantation methods for clinical use, still remain, DPSCs could be promising stem cells sources for various clinical applications, because of their easy isolation by a noninvasive procedure without ethical concerns.

Background: In 1970, C.B. Huggins (Nobel award winner) and M.R. Urist (bone morphogenetic protein discoverer) reported that rat demineralised dentin induced bone at four weeks and the induced bone existed more than one year. We achieved the autograft of demineralised dentin matrix (DDM) for sinus augmentation as a first clinical case in 2002. Dentin is almost similar to bone in chemical components. Our idea is a recycle use of the extracted tooth as an absorbable, collagenous material with cross-linking for bone regeneration. Objective: The aim of this study was to observe tissue reaction after DDM autograft, histologically. Methods: Preparation of DDM granules: non-functional, vital teeth was crushed, decalcified in 2.0% nitric acid solution, and extensively rinsed in cold distilled water. Case 1: A 48-year-old male revealed an atrophied left-upper jaw and received DDM graft from non-functional molars for sinus augmentation in 2002. Case 2: A 66-year-old female presented a bony healing failure in the extracted socket for two months. The immediate graft of wisdom teeth-derived DDM was carried out by using our newly developed electric mill system in 2009. Biopsy tissues of both cases were taken at five months after the graft. Findings and Conclusion: Case 1 showed that mature bone interconnected between the remained DDM. Case 2 showed that new bone formation occurred on both dentin and cementum area. DDM was harmonised with original tissue. These evidences indicated that patient-own DDM could be recycled for successful bone regeneration and opened a novel way as biological scaffold.

Determination of stem cell hierarchy/lineage is indispensable for a better understanding and augmentation of many aspects of medical sciences, including the mechanisms of tissue development and maintenance of tissue homeostasis, as well as disease development. It also has implications in the fi eld of tissue regeneration for medical treatments and disease modeling for drug discovery using iPSC technology. In this presentation, I would like to introduce recent discoveries about stem cell hierarchy/lineage of mesenchymal stem cells in vivo, and what these new discoveries will provide in the promotion of the fi eld of tissue regeneration and drug discoveries. I would be delighted to share and discuss these fi ndings with members.

OBJECTIVES:Regenerating critical-size bone injury is a major problem that continues to inspire the design of new graft materials. Therefore, tissue engineering has become a novel approach for targeting bone regeneration applications. Human teeth are a rich source of stem cells, matrix, trace metal ions, and growth factors. A vital tooth-derived demineralized dentin matrix is acid-insoluble and composed of cross-linked collagen with growth factors. In this study, we recycled human non-functional tooth into a unique geometric dentin scaffold, entitled perforated root-demineralized dentin matrix (PR-DDM). The aim of this study was to evaluate the feasibility of PR-DDM as the scaffold for regenerating bone in critical-size iliac defects.MATERIAL AND METHODS:Artificial macro-pores (1 mm in diameter) were added to human vital wisdom tooth after removing the enamel and pulp portions. The modified tooth was demineralized in 0.34 N HNO3 for 30 min and is referred to as PR-DDM scaffold. Critical-size defect (10 mm × 15 mm × 9 mm Ø) was created in the iliac crest of six adult sheep. The in vivo bone regeneration by the scaffold was evaluated by micro-CT, 3D micro-CT, and histological examination at 2 and 4 months post-implantation.RESULTS:PR-DDM exhibited better bone ingrowth, especially in the artificial macro-pores. The results of micro-CT and 3D micro-CT revealed good union between scaffold and native bone. New bone formation was observed in almost all portions of PR-DDM. Higher bone volume inside the scaffold was detected at 4 months compared with 2 months. New bone ingrowth was ankylosed with PR-DDM, and both osteoinduction and osteoconduction capability of PR-DDM were confirmed histologically. The ratio of new bone formation was higher at 4 months compared with 2 months by histomorphometric analysis.CONCLUSIONS:Altogether, these results demonstrated that the human tooth-derived graft material with a unique geometric structure, PR-DDM, contributed to active bone ingrowth in critical-size bone defects. This novel scaffold may have great utility in the near-future clinical application.

Dentin matrix is well known as the most insoluble collagen in human body. We already confirmed the osteoinductive property by granules of human demineralized dentin matrix (DDM) histologically. Human DDM granules and human demineralized root-dentin (DRD) mass were prepared from adult vital teeth. The hard tissue induction by DDM alone or DRD alone was estimated at 4 weeks after implantation. The DDM alone induced bone and cartilage independently. In addition, the bioassay by recombinant human BMP-2 (5.0 µg)/DDM or BMP-2 (5.0 µg)/DRD was estimated in mouse subcutaneous or intramuscular tissues, respectively. Histological examination showed that the BMP-2/DDM induced bone and marrow, and the DDM granules were partially absorbed by new bone. The morphometric analysis demonstrated that the BMP-2/DDM showed 36.3% in the volume of bone and marrow, while the DDM alone showed 1.3% at 4 weeks. Moreover, the BMP-2/DRD also induced active bone formation on the root surface and in the pulp cavity. These results indicate that BMP-2 significantly accelerated bone formation in decalcified dentin implants. Human recycled DDM and DRD might be effective materials as osteoinductive collagenous carriers of BMP-2 for bone engineering.

BACKGROUND Oral squamous cell carcinoma and the most common oral pre-malignancies appear to be related to the habit of betel-quid chewing in Sri Lanka. Although hypermethylation of the tumour suppressor genes in oral cancer have been well documented, little information has been available concerning hypermethylation in oral pre-cancerous lesions. In the present study, we investigated the hypermethylation of p14, p15 and p16 in pre-cancerous lesions including epithelial dysplasia and submucous fibrosis. METHODS All samples were obtained from patients with a betel-quid chewing habit in Sri Lanka. Sixty-four patients were clinically diagnosed with leukoplakia, and histopathologically diagnosed with mild or severe dysplasia. Ten patients were diagnosed with submucous fibrosis without epithelial dysplasia. CpG island hypermethylation was assessed by a methylation-specific PCR method. Immunohistochemical staining was performed using anti-p53 antibodies. RESULTS A high frequency of hypermethylation of p14, p15 and p16 was detected in the pre-cancerous lesions, although no hypermethylation was found in normal epithelium. The frequency of hypermethylation was higher than that of positive staining for p53 mutation except in the case of p16 in mild dysplasia. No significant correlation was observed between p53-positive reactions and hypermethylation in any lesions. The hypermethylation was highly detectable even in p53-negative lesions, suggesting that hypermethylation of p14, p15 and p16 occur regardless of whether the lesions have p53 mutations or not. CONCLUSIONS The present study indicates that hypermethylation may be involved in the pathogenesis of oral pre-cancerous lesions associated with betel-quid chewing in Sri Lanka.

Ameloblastic carcinoma is described in the updated World Health Organization (WHO) classification as a rare malignant lesion. Ameloblastic carcinoma meeting the WHO criteria may arise either as a result of malignant change in a pre-existing benign ameloblastoma (carcinoma ex ameloblastoma) or as a primary malignant ameloblastoma not preceded by an ordinary ameloblastoma (de novo carcinoma). We report a case of ameloblastic carcinoma ex ameloblastoma and examine how this case underwent malignant transformation. The DNA was extracted separately from benign and malignant areas in paraffin sections of the tumor. Direct sequencing showed no genetic mutation of exons 5-8 of the p53 gene. Hypermethylation of CpG islands of the p16 gene was detected in the malignant parts of the tumor. The results indicate that hypermethylation of p16 may have been involved in the malignant transformation of the ameloblastoma in the present case.

Human beta-defensin (hBD) 2 is an epithelial antimicrobial peptide. We studied single-nucleotide polymorphisms in the gene of hBD-2 in a Japanese population, and estimated the effect of a polymorphism in the promoter/enhancer region on the transcriptional activity. By sequencing the hBD-2 gene of 50 unrelated individuals, we detected one SNP in exon 2 and nine SNPs in the promoter/enhancer region. The SNP in the coding region at the + 1765 position is synonymous [CCC (Pre) -> CCT (Pre)]. One SNP in the promoter region (- 1029) is located at the consensus sequence for NF-IL6 binding. By luciferase reporter assay and electrophoretic mobility shift assay, the wild-type (G) of - 1029 showed signifi cantly lower transcriptional activity than did the variant-type (A). The SNP at position - 1029 may infl uence the hBD-2 expression and cause genetic variations in susceptibility to infectious diseases.