• Journal of Periodontal and Implant Science
• /
• v.30 no.3
• /
• pp.527-538
• /
• 2000

Several extraction cases with advanced bone loss as a result of periodontal disease, root or labial bone fracture, extensive caries, and periapical lesions occur esthetic, functional problems and severe bone loss. Therefore, to treat these cases used several surgical methods and socket preservation among this therapies have been evaluated simple, effective and good prognosis in the implant placement. Socket preservation therapy have been used with barrier membranes or/and graft materials. Deproteinized bovine bone mineral have been evaluated ideal grafting materials. Recently, calcium-phosphate thin film coated bovine bone powders were developed in our country, but the study for these material wasn't reported. When two types of xenograft materials were implanted in extraction sockets of Beagle dogs, the effects of these were analyzed after 4 weeks and 8 weeks histological views. The results of this study were as follows. 1. In control groups, 4 weeks after implantation, the extraction sockets were filled with connective tissue which has dilated vessels and epithelial growth. And after 8 weeks, irregular connective bundles were observed. But new bone formation was not seen. 2. In Bio-Oss groups, epithelial growth was not seen and bone powder was covered with connective tissue fiber. New bone formation was found around the interproximal bone. There was no special change seen after 8 weeks, connective tissue fibers became more regular, and bone growth near bone powder was not made well. 3. In Ca-P BBP groups, epithelial cells didn't grow in the extraction sockets, there was a lot of new bone made around the bone powder after 8 weeks, new bone around bone powder was replaced with mature bone. It is thought that bone powder grafting into the extraction sockets is very useful for conservation of ridge, and Ca-P BBP is more effective in bone formation than Bio-Oss.

• International Journal of Oral Biology
• /
• v.46 no.4
• /
• pp.176-183
• /
• 2021

Oral squamous cell carcinoma (OSCC) metastasis is characterized by distant metastasis and local recurrence. Combined chemotherapy with cisplatin and 5-fluorouracil is routinely used to treat patients with OSCC, and the combined use of gefitinib with cytotoxic drugs has been reported to enhance the sensitivity of cancer cells in vitro. However, the development of drug resistance because of prolonged chemotherapy is inevitable, leading to a poor prognosis. Therefore, understanding alterations in signaling pathways and gene expression is crucial for overcoming the development of drug resistance. However, the altered characterization of Ca²⁺ signaling in drug-resistant OSCC cells remains unclear. In this study, we investigated alterations in intracellular Ca²⁺ ([Ca²⁺]_i) mobilization upon the development of gefitinib resistance in human tongue squamous carcinoma cell line (HSC)-3 and HSC-4 using ratiometric analysis. This study demonstrated the presence of altered epidermal growth factor- and purinergic agonist-mediated [Ca²⁺]_i mobilization in gefitinib-resistant OSCC cells. Moreover, Ca²⁺ content in the endoplasmic reticulum, store-operated calcium entry, and lysosomal Ca²⁺ release through the transient receptor potential mucolipin 1, were confirmed to be significantly reduced upon the development of apoptosis resistance. Consistent with [Ca²⁺]_i mobilization, we identified modified expression levels of Ca²⁺ signaling-related genes in gefitinib-resistant cells. Taken together, we propose that the regulation of [Ca²⁺]_i mobilization and related gene expression can be a new strategy to overcome drug resistance in patients with cancer.

• International Journal of Oral Biology
• /
• v.48 no.1
• /
• pp.1-7
• /
• 2023

Oral squamous cell carcinoma (OSCC), which accounts for approximately 90% of oral cancers, has a high rate of local recurrence and a poor prognosis despite improvements in treatment. Exosomes released from OSCC cells promote cell proliferation and metastasis. Although it is clear that the biogenesis of exosomes is mediated by the endosomal sorting complex required for transport (ESCRT) machinery, the gene expression pattern of ESCRT, depending on the cell type, remains elusive. The exosomal release from the human OSCC cell lines, HSC-3 and HSC-4, and their corresponding gefitinib-resistant sub-cell lines, HSC-3/GR and HSC-4/GR, was assessed by western blot and flow cytometry. The levels of ESCRT machinery proteins, including Hrs, Tsg101, and Alix, and whole-cell ubiquitination were evaluated by western blot. We observed that the basal level of exosomal release was higher in HSC-3/GR and HSC-4/GR cells than in HSC-3 and HSC-4 cells, respectively. Long-term gefitinib exposure of each cell line and its corresponding gefitinib-resistant sub-cell line differentially induced the expression of the ESCRT machinery. Furthermore, whole-cell ubiquitination and autophagic flux were shown to be increased in gefitinib-treated HSC-3 and HSC-4 cells. Our data indicate that the expression patterns of the ESCRT machinery genes are differentially regulated by the characteristics of cells, such as intracellular energy metabolism. Therefore, the expression patterns of the ESCRT machinery should be considered as a key factor to improve the treatment strategy for OSCC.

• Journal of Periodontal and Implant Science
• /
• v.25 no.3
• /
• pp.741-755
• /
• 1995

Currently titanium is the material of choice for implants because of its biological acceptance. This high degree of biocompatibility is thought to result, in part, from the protective and stable oxide layer that presumably aids in the bonding of the extracellular matrix at the implant-tissue interface. Endosseous dental implants are interfaced with bone, connective tissue, and epithelium when implanted into the jaw bone. The soft tissue interface including connective tissue and epithelium is one of the most critical factors in the determination of implant maintenance and prognosis. For maintenance of failing or failed implants, it is essential to treat the implant fixture surface to remove bacterial endotoxins and make a surface tolerated by surrounding soft and hard tissues. In this study, the effect of mechanical treatment on titanium plasma sprayed implant on adhesiveness and proliferation of human gingival fibroblasts and changed surface characteristics were studied. titanium plasma sprayed discs manufactured by Friedrichsfeld company were treated with loaw speed stone bur, a rubber point and a jetpolisher. Its surface components were analyzed with Energy dispersive X-ray spectroscopy to evaluate whether the surface characteristics were altered or not. To observe the spreading pattern of the human gingival fibroblasts which attached to the all specimens author used the scanning electron microscope. The results were as follows : Pure titanium and plasma sprayed titanium, stone polished titanium showed titanium peak and small amout of aluminum, so there was no alteration on surface characteristics. Under the scanning electron microscopic examination in the initial attachment of human gingival fibroblast, there was a slight enhancement in pure titanium, stone polished titanium than plasma sprayed titanium. After 6 hours, the pure titanium and stone polished titanium showed human gingival fibroblasts were elongated and connected with numerous processes. Human gingival fibroblasts were more intimately attached on the pure titanium discs than on the other discs. The human gingival fibroblasts attached on the plasma sprayed titanium by thin and elongated processes. After 24 hours, the human gingival fibroblasts connected with each other via numerous processes and compeletly covered the pure titanium and stone polshed titanium discs. Human gingival fibroblasts had multiple point contacts with more long and thin lamellopodia and showed a little bare surface on plasma sprayed titanium discs.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.32 no.4
• /
• pp.263-273
• /
• 2016

In the implant prosthetic procedure, the soft tissue reaction was varied with the material and surface treatment of the abutment. It may be the cause of the peri-implantitis, and hence it can affect the long-term prognosis of the implant prosthesis. Titania and zirconia abutment presented superior biocompatibility and stable soft tissue reaction, while gold alloy abutment showed unfavorable reaction sometimes. A soft tissue reaction can be differed by the surface characteristics even in the same material type. Because rougher surface induces a bacterial attachment, the part contacting a soft tissue should have smooth surface. Additional surface treatment can enhance the cellular response without increasing bacterial attachment. Repeated removal and insertion of the abutment and the shape of the abutment may affect the soft tissue reaction, also. Ultrasonic cleaning and argon plasma cleaning are effective way to clean the retained micro-dust on the customized abutment.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.42
• /
• pp.10.1-10.9
• /
• 2020

Background: The aim of this study was to evaluate the long-term clinical stability of implants with acid-etched surfaces sandblasted with alumina using retrospective analyses of the survival rate, success rate, primary and secondary stability, complications, and marginal bone loss of the implants. Methods: Patients who had implants placed (TS III SA, SS II SA, SS III SA, and U III SA) with SA surfaces from Osstem (Osstem Implant Co., Busan, Korea) at the Seoul National University Bundang Hospital, from January 2008 to December 2010 were selected for the study. Patients' medical records and radiographs (panorama, periapical view) were retrospectively analyzed to investigate sex, age, location of implantation, diameter, and length of the implants, initial and secondary stability, presence of bone grafting, types of bone grafting and membranes, early and delayed complications, marginal bone loss, and implant survival rate. Results: Ninety-six implants were placed in 45 patients. Five implants were removed during the follow-up period for a total survival rate of 94.8%. There were 14 cases of complications, including 6 cases of early complications and 8 cases of delayed complications. All five implants that failed to survive were included in the early complications. The survival of implants was significantly associated with the occurrence of complications and the absorption of bone greater than 1 mm within 1 year after prosthetic completion. In addition, the absorption of bone greater than 1 mm within 1 year after prosthetic completion was significantly associated with the occurrence of complications, primary stability, and implant placement method. Five cases that failed to survive were all included in the early complications criteria such as infection, failure of initial osseointegration, and early exposure of the fixture. Conclusions: Of the 96 cases, 5 implants failed resulting in a 94.8% survival rate. The failed implants were all cases of early complications such as infection, failure of initial osseointegration, and early exposure of the fixtures. Periimplantitis was mostly addressed through conservative and/or surgical treatment and resulted in very low prosthetic complications. Therefore, if preventive measures are taken to minimize initial complications, the results can be very stable.

• The Journal of Korean Academy of Prosthodontics
• /
• v.61 no.2
• /
• pp.125-134
• /
• 2023

When the patient with class III malocclusion needs extensive oral rehabilitation due to multiple missing teeth, accurate diagnosis, and careful analysis, such as the patient's occlusal relationship, facial changes, and evaluation of the temporomandibular joint are essential. Orthognathic surgery is often performed for aesthetic improvement, depending on the patient's chief complaint. If it is not possible due to certain circumstances, partial aesthetic improvement can be achieved through minimal elevation of the vertical dimension. As this patient may have unexpected issues, such as temporomandibular joint disorder, oral habits like bruxism, and masticatory muscle tension, it was determined whether the patient could adjust to a reversible temporary removable partial denture. After this, the maxillary implant-supported fixed prostheses and the mandibular fixed prostheses were used to achieve stable posterior support and to partially improve the maxillary anterior esthetics. The patient was satisfied with the results both aesthetically and functionally. The prognosis is expected to be good if regular check-ups are conducted.

• Journal of Periodontal and Implant Science
• /
• v.39 no.3
• /
• pp.375-381
• /
• 2009

Purpose: Root resection can be a valuable procedure when the tooth in question has a high strategic value. The prognosis of root resection has been well documented in previous studies, but the results focused on the palatal root resection have not been discussed in depth. I represent here the short term effectiveness of palatal root resection of maxillary first molars. Methods: Palatal root resection was performed on maxillary first molars of three patients. All the palatal roots were floating state on the radiographic finding and showed full probing depth and purulent exudation at initial examination. Reduction of palatal cusp and occlusal table was performed concomitantly. Endodontic therapy was completed after root resection. Results: Compromised maxillary first molars were treated successfully by palatal root resection in 3 cases. The mobility of resected tooth was decreased a little bit. The probing pocket depth of remaining buccal roots was not increased compared to initial depth. All the patients satisfied with comfort and cost effective results and the fact they could save their natural teeth. Conclusions: Within the above results, palatal root resection is an effective procedure treating compromised maxillary first molar showing advanced palatal bone loss to root apex with or without pulp involvement when proper case selection is performed.

• Journal of Periodontal and Implant Science
• /
• v.29 no.1
• /
• pp.95-102
• /
• 1999

The purpose of this study was to observe histopathologically the influence of advanced periodontitis on pulp tissue, and to conclude the correlation between the results with clinical manifestations. The samples were teeth with over 7mm pocket depth and over 50% radiographic bone loss. These were diagnosed to have very poor prognosis and thus planned to be extracted. Those with any of following conditions were excluded from the samples, loss of vitality, periapical pathology, restoration or prosthesis, dental caries, and attrition or abrasion. It was because these conditions could affect pulp without any correlation with periodontal disease. For the experiment, 17 teeth from 11 patients were selected. Average age of patient was 47. Each tooth was examined for following categoris; pocket depth, gingival recession, electric pulp test, mobility, percussion test, sensitivity test. The extracted teeth were fixed buffered neutral formalin solution. It was decalcified using 4% nitric acid. Sliced histological samples observed using light microscope, for pulp status, and severeity of inflammation. 4 samples were excluded due to histologic sample discrepency. Thus 13 samples were subject to observation. 4 showed normal conditions. Focal reversable pulpitis was shown in 5 samples. Chronic pulpitis was observed 1 sample. Pulpal abscess was observed in 3 samples.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.40 no.4
• /
• pp.188-194
• /
• 2014

For large membrane perforations that develop during sinus-bone grafting, we performed repairs using a pedicled buccal fat pad and a resorbable collagen membrane simultaneously with the bone graft. This study included eight patients. Postoperative maxillary sinusitis developed in two patients, which we managed with incision and drainage, and antibiotics. Ultimately, six patients received 12 implants, three of which failed (75% success). Implant replacement was performed after the removal of the failed replacement, at which point the prosthetic treatment was considered complete. In all of the six cases that we were able to follow-up with, the sinus-bone graft was healing favorably. We observed that the sinus bone height decreased gradually with time. Based on these case series, we conclude that our procedure of repairing large sinus-membrane perforations with a pedicled buccal fat pad and a collagen membrane is a reliable technique.