• 구강회복응용과학지
• /
• 제21권1호
• /
• pp.33-42
• /
• 2005

This study was performed to investigate the surface properties and in vitro biocompatibility of electrochemically oxidized Ti-6Al-7Nb alloy by anodic spark discharge technique. Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1000 SiC paper, ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed using a regulated DC power supply. The applied voltages were given at 240, 280, 320, and 360 V and current density of $30mA/cm^2$. Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. Samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ during 30 days. The results obtained were summarized as follows; 1. The oxide films were porous with pore size of $1{\sim}5{\mu}m$. The size of micropores increased with increasing the spark forming voltage. 2. The main crystal structure of the anodic oxide film was anatase type as analyzed with thin-film X-ray diffractometery. 3. Needle-like hydroxyapatite (HA) crystals were observed on anodic oxide films after hydrothermal treatment at $300^{\circ}C$ for 2 hours. The precipitation of HA crystals was accelerated with increasing the spark forming voltage. 4. The precipitation of the fine asperity-like HA crystals were observed after being immersed in Hanks' solution at $37^{\circ}C$. The precipitation of HA crystals was accelerated with increasing the spark forming voltage and the time of immersion in Hanks' solution. 5. The Ca/P ratio of the precipitated HA layer was equivalent to that of HA crystal as increasing the spark forming voltage and the time of immersion in Hanks' solution.

• BMB Reports
• /
• 제33권3호
• /
• pp.279-284
• /
• 2000

Using fluorescence probes, 2-(9-anthroyloxy) stearic acid (2- AS) and 12-(9-anthroyloxy) stearic acid (12-AS), we determined the differential effects of local anesthetics (tetracaine-HCI, bupivacaine-HCI, lidocaine-HCI, prilocaine-HCI and procaine-HCI) on the differential rotational rate between the surface (in carbon number 2 and its surroundings including the head group) and the hydrocarbon interior (in carbon number 12 and its surroundings) of the outer monolayer of the total phospholipid fraction liposome that is extracted from synaptosomal plasma membrane vesicles. The anisotropy (r) values for the hydrocarbon interior and the surface region of the liposome outer monolayer were$0.051{\pm}0.001$ and $0.096{\pm}0.001,$ respectively. This means that the rate of rotational mobility in the hydrocarbon interior is faster than that of the surface region. Local anesthetics in a dosedependent manner decreased the anisotropy of 12-AS in the hydrocarbon interior of the liposome outer monolayer, but increased the anisotropy of 2-AS in the surface region of the monolayer. These results indicate that local anesthetics have significant disordering effects on the hydrocarbon interior, but have significant ordering effects on the surface region of the liposome outer monolayer.

• Asian Pacific Journal of Cancer Prevention
• /
• 제16권17호
• /
• pp.7843-7846
• /
• 2015

Background: Some matrix metalloproteinases (MMPs) are involved in invasion and metastasis of head and neck squamous cell carcinoma (HNSCC). However, there are few studies on association between stromelysin-2 (ST-2) and invasive behavior of HNSCC. The purpose of this study was to investigate Stromelysin-2 expression by immunohistochemistry. Materials and Methods: This study was conducted on 81 specimens, including 61 HNSCC and 20 non neoplastic epithelium. Sections with 5 micron thickness were prepared and stained with immunohistochemistry technique. Then expression of ST-2 was evaluated according to percentage of stained cells and intensity of staining. Data were analyzed by SPSS (V.21) using Kruskal-Wallis and Tukey tests (P<0.05). Results: The 61 HNSCC specimens were grades I 36.1%, II 34.4% and III 29.5%. The level of ST-2 expressions were moderate (++) and intensive (+++) in 21.3% and 78.7% of tumors, respectively. The ST-2 expression level was only significant between the tumors with grade I and grade III (P=0.016). Tumors presented ST-2 expression with staining intensity of mild 6.6%, moderate 26.2% and strong 67.2%. Staining intensity of ST-2 in grade I tumors was significantly lower than grade II and grade III (P<0.05), and there was no significant difference between grades II and III (P=0.99). Conclusions: According to this study, the expression of ST-2 is associated with histopathological grade and tumor differentiation in HNSCCs.

• Asian Pacific Journal of Cancer Prevention
• /
• 제13권8호
• /
• pp.4137-4140
• /
• 2012

The authors present five cases of combined oral mucosa-mandible defects reconstructed with the vascularized internal oblique-iliac crest myoosseous free flap. This technique has many advantages compared to other conventional methods such as the radial flap, scapula flap, and fibula flap. Vascularized iliac crest flaps provide sufficient high-quality bone suitable for reconstructing segmental madibular defects. Although fibular flaps allow longer donor bone tissue to be harvested, the iliac crest can provide an esthetic shape for mandibular body reconstruction and also provides sufficient bone height for dental implants. Conventional vascularized iliac crest myoosseous flaps have excessive soft tissue bulk for reconstruction of intraoral soft tissue defects. The modification discussed in the present article can reduce soft tissue volume, resulting in better functional reconstruction of the oral mucosa. Another advantage is that complete replacement of the oral mucosa is observed in as early as one month post-operation. The final mucosal texture is much better than that obtained with other skin paddle flaps, which is especially beneficial for the placement of dental implant prostheses. Donor site morbidity looks to be similar to, if not less than that observed for other modalities in terms of function and esthetics. For combined oral mucosa-mandible defects, the vascularized internal oblique-iliac crest myoosseous free flap shows good results with respect to hard and soft tissue reconstruction.

• 센서학회지
• /
• 제29권4호
• /
• pp.249-254
• /
• 2020

It is difficult to control children who exhibit negative behavior in dental clinics. Various methods are used for preventing pediatric dental patients from being afraid and for eliminating the factors that cause psychological anxiety. However, when it is difficult to apply this routine behavioral control technique, sedation therapy is used to provide quality treatment. When the sleep anesthesia treatment is performed at the dentist's clinic, it is challenging to identify emergencies using the current breath detection method. When a dentist treats a patient that is under the influence of an anesthetic, the patient is unconscious and cannot immediately respond, even if the airway is blocked, which can cause unstable breathing or even death in severe cases. During emergencies, respiratory instability is not easily detected with first aid using conventional methods owing to time lag or noise from medical devices. Therefore, abnormal breathing needs to be evaluated in real-time using an intuitive method. In this paper, we propose a method for identifying abnormal breathing in real-time using an intuitive method. Respiration signals were measured using a 3M Littman electronic stethoscope when the patient's posture was supine. The characteristics of the signals were analyzed by applying the signal processing theory to distinguish abnormal breathing from normal breathing. By applying a short-time Fourier transform to the respiratory signals, the frequency range for each patient was found to be different, and the frequency of abnormal breathing was distributed across a broader range than that of normal breathing. From the wavelet transform, time-frequency information could be identified simultaneously, and the change in the amplitude with the time could also be determined. When the difference between the amplitude of normal breathing and abnormal breathing in the time domain was very large, abnormal breathing could be identified.

• 대한치과기공학회지
• /
• 제29권2호
• /
• pp.173-180
• /
• 2007

There was a great problem about the deposition between materials of a different kind at the beginnings of the introduction of porcelains, however, thereafter the deposition efficiency was settlded to the sufficient level of all user thanks to effort to have studied by many scholars and clinical authorities. But in a clinical process, as the difference of designs has an effect on fractures of porcelains, this researcher divided them into 4 groups of A: 1 mm, B: 2 mm, C: 3 mm, and D: 4 mm, and made 40 pieces to each 10 as the test samples to consider a length axis of tooth for studies in accordance with a position of a finishing line to meet between porcelain and metal at the contact point at the adjacent side to a metal porcelain. The sample materials are those to be use at the open market and the test samples wer completed by the same manufacturing technique to that of existent metal porcelain tube. s a result of the strength test on fractures, the average value is as in the following, A: 1 mm - 8.5bar, B: 2 mm - 10.5bar, C: 3 mm - 14.3bar, and D: 4 mm - 15.0bar. In case of the metal porcelain tube, the more faraway to process parts of metal and porcelain from the contact point of adjacent side has the stronger strength of fractures, Accordingly, the research shows that it had better to keep off more than 3 to consider a ledngth axis of tooth.

• 치과방사선
• /
• 제14권1호
• /
• pp.17-26
• /
• 1984

The purpose of this study was radiographic analysis of the morphology of maxillary sinus in adolescents and adults. In order to analize the morphology of maxillary sinus in view point of anteroposterior width of medial wall, vertical distance between antral floor and nasal floor level, anterior extension, distance between antral floor and maxillary 1st molar apex, and types of lower border of maxillary sinus, specialized maxillary projection and periapical view with paralleling technique was taken. The author examined orthopantomograms and intraoral standard views taken from 400 adolescents and adults ranged 15-65 year-old. The obtained results were as follows: 1. The antero-posterior width of medial wall of maxillary sinus was 32.80mm in 15-19 year-old group, 33.86㎜ in 20-24 year-old group, 34.09㎜ in 25-29 year-old group, and 33.67㎜ in 30-65 year-old group, and the left maxillary sinus was somewhat smaller than the right. 2. The vertical distance between antral floor and nasal floor level was 8.49㎜ in 15-19 year-old group, 9.05㎜ in 20-24 year-old group, 8.95㎜ in 25-29 year-old group, and 8.32㎜ in 30-65 year-old group. 3. The order of anterior extension of maxillary sinus were distal half of canine, mesial half of canine, mesial half of 1st premolar, and distal half of 1st premolar. 4. The distance between antral floor and maxillary 1st molar were 4.36㎜ in 15-19 year-old group, 4.77㎜ in 20-24 year-old group, 3.58㎜ in 25-29 year-old group, and 2.33㎜ in 30-65 year-old group. 5. The order of the types of lower border of maxillary sinus were entire downward type, close type, partially downward type, waving type, separating type, and indistinct. In the types of antral floor, there was a tendency to increase the seperating type with age.

• 대한치과보철학회지
• /
• 제55권1호
• /
• pp.46-52
• /
• 2017

임시보철물은 고정성 보철물로의 수복 과정에서 지대치 보호 및 기능과 심미성 회복의 측면에서 중요한 역할을 수행한다. 특히 이를 장착한 상태로 최종 수복 전에 장기간의 관찰이 필요한 환자에서 그 중요성이 더욱 강조되나, 상대적으로 낮은 강도로 인하여 잦은 파절이 발생할 수 있으며 이를 방지하기 위해 강화된 임시보철물의 제작을 고려할 수 있다. 이 문헌에서는 교합 수직 고경의 증가를 필요로 하는 환자의 증례를 소개하고자 하였으며, 수직 고경 증가의 영향으로 임시보철물 사용 시 더 큰 부하의 작용 및 장기간의 사용이 예상되었다. 이에 주조 금속 하부구조물을 첨가하여 bis-acryl 레진으로 강화된 임시보철물을 제작하였으며, 약 4개월의 관찰 기간 동안 만족스러운 결과를 보였다.

• The Journal of Advanced Prosthodontics
• /
• 제12권4호
• /
• pp.225-232
• /
• 2020

PURPOSE. This study aimed to fabricate provisional crowns at varying build directions using the digital light processing (DLP)-based 3D printing and evaluate the marginal and internal fit of the provisional crowns using the silicone replica technique (SRT). MATERIALS AND METHODS. The prepared resin tooth was scanned and a single crown was designed using computer-aided design (CAD) software. Provisional crowns were printed using a DLP-based 3D printer at 6 directions (120°, 135°, 150°, 180°, 210°, 225°) with 10 crowns in each direction. In total, sixty crowns were printed. To measure the marginal and internal fit, a silicone replica was fabricated and the thickness of the silicone impression material was measured using a digital microscope. Sixteen reference points were set and divided into the following 4 groups: marginal gap (MG), cervical gap (CG), axial gap (AG), and occlusal gap (OG). The measurements were statistically analyzed using one-way ANOVA and Dunnett T3. RESULTS. MG, CG, and OG were significantly different by build angle groups (P<.05). The MG and CG were significantly larger in the 120° group than in other groups. OG was the smallest in the 150° and 180° and the largest in the 120° and 135° groups. CONCLUSION. The marginal and internal fit of the 3D-printed provisional crowns can vary depending on the build angle and the best fit was achieved with build angles of 150° and 180°.

• 대한소아치과학회지
• /
• 제2권1호
• /
• pp.67-75
• /
• 1975

The conserative treatment of the necrotic and infected primary molars is often necessary in order to avoid extractions which may lead to inability to masticate or loss of space and subsequent problems concerning the development of the occlusion in the permanent dentition. The purpose of this study was to evaluate the clinical significance of the conservative treatment of the infected primary molars with necrotic pulps employing the formocresol pulpotomy technique same as in vital teeth and surgical intervention in the cases with a parulis, fistula or cellulitis. The materials consisted of 25 primary molars of 9 boys and 4 girls ranging in age from 4 to 7 years. This study included clinical and radiographic observation at 3-month intervals postoperatively. The following results were obtained. 1. Clinically, 20 cases of 25 were successful, exhibiting no clinical problems such as fistula, mobility, toothache and tenderness to percussion, etc. 5 cases were regarded as failures. 2. Radiographiclly, 14 cases revealed normal features, in 6 cases slight rarefaction was observed in the periapical and interradicular region, and marked periapical and interradicular rarefaction was observed in 5 cases. 3. Marked bony deposition was observed in the periapical and interradicular regions in all the remainder except for 5 failurese. 4. Pathologic root resorption was observed in 2 cases. 5. No alveolodental ankylosis was observed. 6. Regeneration of the dental sac of the permanent tooth was observed in 1 case of 2 cases which had revealed loss of the dental sac.