• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.2
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• pp.185-190
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• 2001

We described three cases of immediate reimplantation of a frozen-thawed autogenous mandible composed of a mixture of iliac bone, marrow, and particulate hydroxyapatite in tumors of the mandible. Acceptable outcomes were obtained in three patients who underwent immediate autogenous mandibular graft reconstruction. The conditions leading to successful outcome of the procedure are also discussed. Reimplantation of frozen autogenous lesioned mandible was performed in three patients with mandibular tumors. Two reimplanted grafts survived without complications following surgery. One case had postoperative infection that resolved with appropriate antibiotic treatment. There were no recurrences of the primary lesions. Satisfactory facial contour after surgery was achieved. These results are most promising, and we believe that, with further refinement, this technique will offer a new and acceptable modality for facial reconstruction in patients with cancer.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.548-552
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• 2010

The submandibular gland is the second largest major salivary gland, which secretes 40% of the total daily saliva. Owing to its anatomic characteristics as well as the high viscosity and basicity of the saliva, sialolithiasis is found most commonly in the submandibular gland. Sialolithiasis that cannot be treated by conservative treatment is conventionally removed by an excision of the submandibular gland. Generally, an excision of the submandibular gland is performed via an extra-oral approach but the disadvantages of this treatment include a risk of injuring the facial nerve and scar formation. Case reports have revealed an even less invasive intraoral surgical technique for the removal of sialolith that does not affect the submandibular gland function. The functional recovery of the gland, complications and recurrence rates after surgery with this conservative intraoral procedure were all successful. We report 5 patients from the department of Oral and Maxillofacial Surgery at Dental Hospital, Yonsei University, who had undergone a resection of the sialolith though the intraoral approach with successful results.

• The Journal of Korean Academy of Prosthodontics
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• v.33 no.2
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• pp.198-209
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• 1995

In order to evaluate the fitness and the degree of rounding of porcelain margins in collarless metal cermic restorations, collarless metal ceramic restorations were fabricated with shoulder margins of 90 and 120 degress, each consisting of ten specimens, on master dies through the direct lift technique. And ten metal ceramic restorations with a shoulder 90 degrees were fabricated. All specimens were embedded in resin and sectioned longitudinally. The sections were observed under a stereomicroscope and photographed(${\times}$200). The labial marginal gap between the die and the porcelain margin were measured with a scale. The space between the porcelain margin and the die, that is formed from marginal rounding and cementation were calculated with a computer coordinating area curvimeter. The following results were obtained. 1. There was no statistical difference between the fitness of porcelain margin of collarless metal ceramic restorations and marginal fitness of metal ceramic restoration. 2. There was no statistical difference between a shoulder of 90 and 120 degrees in the fitness of porcelain margin of collarless metal ceramic resorations. 3. Collarless metal ceramic restorations with a shoulder of 90 degrees and 120 degrees showed significantly more labial marginal rounding than metal ceramic restorations. 4. There was no statistical difference between a shoulder of 90 and 120 degrees in rounding of porcelain margin of collarless metal ceramic restorations. According to the results, rounding of porcelain margins can be observed in collarless metal ceramic restorations. Thus, there is a need for improvement in dental materials and techniques to minimize this problem, Furthermore, care should be exercised during the clinical procedure.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.6
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• pp.736-744
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• 2005

Statement of problem. Initial stability of implant is an important factor for predicting osseointegration. It requires a rapid, non-invasive, user-friendly technique to frequently assess the implant stability and the degree of osseointegration. Purpose. The aim of this study was to evaluate the correlation between the resonance frequency analysis (RFA) and the radiographic method for peri-implant bone change under in vitro conditions. Material and Method. Twenty implants of 3.75 mm in diameter(Neoplant, Neobiotech, Korea) were used. To simulate peri-implant bone change, 2 mm-deep $45^{\circ}$ range horizontal defect and 2 mm-deep $90^{\circ}$ range horizontal defect area were serially prepared perpendicular to the X-ray beam after conventional implant insertion. Customized film holding device was fabricated to standardize the projection geometry for serial radiographs of implants and direct digital image was obtained. ISQ values and gray values inside threads were measured before and after peri-implant bone defect preparation. Results. Within a limitation of this study, ISQ value of resonance frequency analysis was changed according to peri-implant bone change (p<0.05) and gray value of radiographic method was changed according to peri-implant bone change (p<0.05). There was no correlation between the ISQ value and the gray value for peri-implant bone change (p>0.05). But, in horizontal defect condition, relatively positive correlation were between ISQ and gray values(r=0.663). Conclusion. This results provided a possibility that peri-implant bone change may be evaluated by both RFA and radiographic method.

• The Journal of Advanced Prosthodontics
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• v.4 no.2
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• pp.103-108
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• 2012

PURPOSE. Debonding of a composite resin core of the fiber post often occurs at the interface between these two materials. The aim of this study was to evaluate the effects of different surface treatment methods on bond strength between fiber posts and composite core. MATERIALS AND METHODS. Sixty-four fiber posts were picked in two groups (Hetco and Exacto). Each group was further divided into four subgroups using different surface treatments: 1) silanization; 2) sandblasting; 3) Treatment with 24% $H_2O_2$, and 4) no treatment (control group). A cylindrical plexiglass matrix was placed around the post and filled with the core resin composite. Specimens were stored in 5000 thermal cycles between $5^{\circ}C$ and $55^{\circ}C$. Tensile bond strength (TBS) test and evaluation using stereomicroscope were performed on the specimen and the data were analyzed using two-way ANOVA, Post Hoc Scheffe tests and Fisher's Exact Test (${\alpha}$=.05). RESULTS. There was a significant difference between the effect of different surface treatments on TBS ($P$ <.001) but different brands of post ($P$=.743) and interaction between the brand of post and surface treatment ($P$=.922) had no significant effect on TBS. Both silanization and sandblasting improved the bonding strength of fiber posts to composite resin core, but there were not any significant differences between these groups and control group. CONCLUSION. There was not any significant difference between two brands of fiber posts that had been used in this study. Although silanization and sandblasting can improve the TBS, there was not any significant differences between surface treatments used.

• Journal of the korean academy of Pediatric Dentistry
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• v.8 no.1
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• pp.37-46
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• 1981

This study was undertaken to evaluate the pulpal responses to the pulp-capping materials such as glutaraldehyde and formocresol in pulpotomy technique, especially in the primary dentition. Mandibular primary canines and molars of 5 dogs (aged about 8-9 weeks)were selected for this study. The intervals of observation for histologic study of pulpotomized primary teeth with 2% glutaraldehyde, formocresol and calcium hydroxide in the usual manner ranged from 2 hours, 1 week, 2 weeks, 3 weeks and 5 weeks after experiments respectively. Each specimens were fixed with 10% formalin and decalcified in 5% nitric acid. All slides were stained with Hematorylin-Eosin and examined histopathologically. The results were as follows; 1. In calcium hydroxide groups, formation of dentin bridge was initiated in 1 week after experiments and completed in 5 weeks after experiments. 2. Formation of dentin bridge was not seen, whereas necrosis of pulp tissue was noted, in formocresol and glutaraldehyde groups. 3. Duration of tissue reactions and tissue changes were similar, in formocresol and glutaraldehyde groups. 4. In formocresol and glutaraldehyde groups, amputation surfaces of the pulp were covered with blood clots, beneath which coagulation necrois was noted, but inflammatory cells were not prominent, in 2 hours and 1 week after experiments. But coagulation necrosis was proceeded to the apical portion, accompanied by infiltration of inflammatory cells, since 2 weeks after experiments. And suppuration or gangrene of the pulp tissue were noted in 3 weeks and 5 weeks groups. 5. Suppuration or gangrene of pulp seemed to provoke the resorption of dentin wall, and inflammatory changes and resorption of roots were noted in the periodontal membrane near the periapical region. 6. As compared with calcium hydroxide groups, resorption of the root was pronounced in form or cresol and glutaraldehyde groups. Effects of medicaments to the succedaneous tooth germ were not seen.

• Journal of Dental Rehabilitation and Applied Science
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• v.20 no.1
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• pp.31-41
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• 2004

The osseointegration in implant therapy is achieved following general wound healing mechanism. Platelet play a major role in wound healing process. In addition to blood clot formation, they secrete many growth factors which regulate the attachment, proliferation and differentiation of nearly all cell types. The use of these growth factors is now known to be very effective methods to improve the cellular activity. Platelet-rich plasma which is made with the newly developed technique concentrating platelets 3-folds or more is also proven to be very effective method to stimulate and accelerate the healing of bone and soft tissue. Previous study proved that platelet-rich plasma enhanced the cellular attachment by inducing fibronectin, vitronectin from osteoblast. So, this study was aimed to investigate the effect of platelet-rich plasma on the cellular proliferation and differentiation in vitro. The effect on the proliferation was evaluated by MTT assay. To evaluate autocrine and paracrine effect, conditioned medium was made and compared. By measuring alkaline phosphatase activity, the effect on the cellular differentiation was evaluated. The results were as following: The cellular proliferation of osteoblast cell line increased depending on the concentration of platelet-rich plasma and conditioned medium. The alkaline phosphatase activity increased depending on the concentration of platelet-rich plasma and conditioned medium. These findings imply that platelet-rich plasma enhance the cellular proliferation and differentiation and maximize the cellular activity by using the autocrine and paracrine effect.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.5
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• pp.391-399
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• 2004

Distraction osteogenesis has been thought to be promising technique for replacing bone graft in maxilla and mandible. The purpose of this study was to investigate the expression of osteonectin on distraction osteogenesis. Sixteen rabbits were used for this experiment. Osteotomy was performed between premolar and mental foramen. On the experimental group, distraction device was connected to the respective bone segments. On the control group, bone segments were fixed using plate and screws after osteotomy. Distraction was carried out at the rate of 0.7mm per day to obtain a 4.9mm elongation on the experimental group. After 3 days, 7 days, 14 days, and 28 days two rabbits of each group were sacrificed. The results obtained from this study were as follow : Experimental group was observed that the gaps between the distracted bone edges were occupied by new bone. Expression of Osteonectin were detected throughout the experiment in both groups and Expression of Osteonectin were markedly increased during distraction and consolidation period in experimental group than control group. From these results, it could be stated that distraction was shown to improve and accelerate bone formation and mechanical stress like distraction has considerable effects on osteonectin.

• Journal of Biomedical Engineering Research
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• v.30 no.5
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• pp.393-400
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• 2009

The present study developed a new technique with no physical object on the flow stream but enabling the air flow measurement and easily incorporated with the devices for cardiopulmonary resuscitation(CPR) procedure. A turbulence chamber was formed in the middle of the respiratory tube by locally enlarging the cross-sectional area where the flow related turbulence was generated inducing energy loss which was in turn converted into pressure difference. The turbulence chamber was simply an empty enlarged air space, thus no physical object existed on the flow stream, but still the flow rate could be evaluated. Computer simulation demonstrated stable turbulence formation big enough to measure. Experiment was followed on the proto-type transducer, the results of which were within ${\pm}5%$ error compared to the simulation data. Both inspiratory and expiratory flows were obtained with symmetric measurement characteristics. Quadratic curve fitting provided excellent calibration formula with a correlation coefficient>0.999(P<0.0001) and the mean relative error<1%. The present results can be usefully applied to accurately monitor the air flow rate during CPR.

• Archives of Plastic Surgery
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• v.43 no.2
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• pp.197-203
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• 2016

Background The aim of unilateral breast reconstruction after mastectomy is to craft a natural-looking breast with symmetry. The latissimus dorsi (LD) flap with implant is an established technique for this purpose. However, it is challenging to obtain adequate volume and satisfactory aesthetic results using a one-stage operation when considering factors such as muscle atrophy, wound dehiscence and excessive scarring. The two-stage reconstruction addresses these difficulties by using a tissue expander to gradually enlarge the skin pocket which eventually holds an appropriately sized implant. Methods We analyzed nine patients who underwent unilateral two-stage LD reconstruction. In the first stage, an expander was placed along with the LD flap to reconstruct the mastectomy defect, followed by gradual tissue expansion to achieve overexpansion of the skin pocket. The final implant volume was determined by measuring the residual expander volume after aspirating the excess saline. Finally, the expander was replaced with the chosen implant. Results The average volume of tissue expansion was 460 mL. The resultant expansion allowed an implant ranging in volume from 255 to 420 mL to be placed alongside the LD muscle. Seven patients scored less than six on the relative breast retraction assessment formula for breast symmetry, indicating excellent breast symmetry. The remaining two patients scored between six and eight, indicating good symmetry. Conclusions This approach allows the size of the eventual implant to be estimated after the skin pocket has healed completely and the LD muscle has undergone natural atrophy. Optimal reconstruction results were achieved using this approach.