• Journal of Periodontal and Implant Science
• /
• 제36권3호
• /
• pp.661-671
• /
• 2006

The purpose of this study was to evaluate cumulative survival rate (CSR, %) of mandibular posterior single tooth implants replaced with ITI SLA (sand-blasted, large-grit, acid-etched) implant system and compare the CSR between first and second molar. The findings from the results were as follows; 1. Total of 158 implants were inserted into 147 patients. 68 patients were males, 79 patients were females and their mean age was 47.8 years. 98 implants were placed in first molar area and 60 implants were placed in second molar area. In terms of diameter, implants with wide diameter over 4.8mm dominated (91.1%). Implants with length over lOmm were used (96.2%). 2, In the two cases, there was a slight transient numbness which recovered within 1-2 months. Nine SynOcta screw type abutments demonstrated screw loosening, There were ten cases of crown fallen-out from decementation. 3. Only one failed out of 158 implants. The CSR was 99.4%. The CSRs for first molar and second molar were 99% and 100%, respectively. From the results, it was concluded that single tooth replacement implant in the mandibular posterior area, might be considered as the effective treatment modality comparable to the conventional crown and bridge.

• 대한소아치과학회지
• /
• 제46권1호
• /
• pp.10-20
• /
• 2019

개인의 치령은 연령 추정의 한 지표로 사용되고 있으며, 아동의 성장 단계를 알 수 있는 중요한 지표가 된다. 치령의 변화는 시대의 변화에 따라 크지는 않지만, 꾸준히 변하게 되며 이에 대한 정보의 업데이트의 중요성은 널리 알려져 있다. 이에 이 연구는 진단 모형을 이용해 한국 아동의 치아 맹출 단계에 대한 정보를 제공하고, 이 정보를 바탕으로 치아 맹출 순서를 조사하고 연령 추정을 시행해 보았다. 5 - 13세 아동 488명의 진단 모형을 통해 치아 맹출 단계에 대해 조사하였다. 맹출 단계 정보를 바탕으로 한 영구치의 맹출 순서는 남녀 모두 상악에서는 제1대구치, 중절치, 측절치, 제1소구치, 견치, 제2소구치였으며, 하악에서는 제1대구치, 중절치, 측절치, 견치, 제1소구치, 제2소구치, 제2대구치 순서로 나타났다. 일부 나이에서 견치, 제1,2소구치, 제2대구치에서 남녀 간의 유의한 맹출 단계 수준의 차이를 보였다. 연령별 맹출 단계를 바탕으로 선형회귀분석을 이용해 연령 추정을 시행해 본 결과 남아와 여아의 나이를 결정 계수 0.816와 0.826 수준으로 추정해 볼 수 있었다.

• 대한소아치과학회지
• /
• 제3권1호
• /
• pp.19-31
• /
• 1976

To study the eruption pattern of the mandibular first permanent molar, the author took 263 cases of Oblique Cephalogram from age 3 to 6 years old children and observed the vertical and mesiodistal directional change and tooth axis change. The following results were obtained.; 1. The eruption pattern of the mandibular first permanenl molar was changed at about 60~66 months or calcification stage IX. 2. At the early stage, the path of eruption of the mandibular first permanent molar directed upward and forward and after calcification stage IX it changed to the direction of upward. 3. The height of the alveolar bone of the upper part of the mandibular first permanent molar was almost equal to that of the interseptal bone of the first and second deciduous molar, but the height showed gradual descent afterwards. 4. At the early stage, the distance from the distal end of the mandibular second deciduous molar to the anterior portion of the ascending ramus was 1.2~1.4 times larger than the mesio-distal diameter of the mandibular first permanent molar, but at the later stage it was enlarged 1.7~1.9 times larger than the mesiodistal diameter of the mandibular first permanent molar.

• International Journal of Oral Biology
• /
• 제36권1호
• /
• pp.31-35
• /
• 2011

Teeth develop via a reciprocal induction between the ectomesenchyme originating from the neural crest and the ectodermal epithelium. During complete formation of the tooth morphology and structure, many cells proliferate, differentiate, and can be replaced with other structures. Apoptosis is a type of genetically-controlled cell death and a biological process arising at the cellular level during development. To determine if apoptosis is an effective mechanism for eliminating cells during tooth development, this process was examined in the rat mandible including the developing molar teeth using the transferase-mediated dUTP-biotin nick labeling (TUNEL) method. The tooth germ of the mandibular first molar in the postnatal rat showed a variety of morphological appearances from the bell stage to the crown stage. Strong TUNEL-positive reactivity was observed in the ameloblasts and cells of the stellate reticulum. Odontoblasts near the prospective cusp area also showed a TUNEL positive reaction and several cells in the dental papilla, which are the forming pulp, were also stained intensively in this assay. Our results thus show that apoptosis may take place not only in epithelial-derived dental organs but also in the mesenchyme-derived dental papilla. Hence, apoptosis may be an essential biological process in tooth development.

• Imaging Science in Dentistry
• /
• 제38권1호
• /
• pp.17-22
• /
• 2008

Purpose: It is important to determine the bucco-lingual inclination of implants on radiographs before the implant surgery. The purpose of this study was to compare the buccolingual inclination in alveolar bone and the tooth with dental cone beam CT and to prepare the standard for the buccolingual inclination of implant. Materials and Methods: Axial, panoramic, and buccolingually sectioned images of 80 implant cases with stent including straight marker using CB $Mercuray^{TM}$ (Hitachi, Japan) were evaluated. The comparison of the buccolingual inclination of remained alveolar bone with the tooth and the marker on butcolingually sectioned views was performed statistically. Results: The average buccolingual inclination of remained alveolar bone and tooth was $82.8{\pm}4.6^{\circ}\;and\;85.8{\pm}4.7^{\circ}$ (p<0.05, r=0.96) at the 1st molar area and $76.4{\pm}1.7^{\circ}\;and\;82.7{\pm}1.7^{\circ}$ respectively (p>0.05, r=0.12) at the 2nd premolar area in upper jaw. The average buccolingua1 inclination of remained alveolar bone and tooth was $81.3{\pm}8.3^{\circ}\;and\;87.5{\pm}6.3^{\circ}$ (p>0.05, r=0.85) at the lower 2nd premolar area and $94.3{\pm}6.6^{\circ}\;and\;93.3{\pm}7.2^{\circ}$ respectively (p>0.05, r=0.91) at the 1st molar area in lower jaw. The inclinations of markers were very different from those of remained bone at the most of areas except the upper 2nd premolar area (r=0.79). Conclusion: We recommend dental CBCT analysis for determining the buccolingual inclination of dental implant, because of significant difference, in average, between the bucco1ingual inclination of remained alveolar bone and tooth.

• 대한치과교정학회지
• /
• 제49권2호
• /
• pp.97-105
• /
• 2019

Objective: This study was performed to evaluate the accuracy and reliability of a newly designed method to achieve mandibular dental model superimposition, using voxel-based cone-beam computed tomography (CBCT) registration. Methods: Fourteen dry cadaveric mandibles and six teeth extracted from patients with severe periodontitis were used to establish 14 orthodontic tooth-movement models. The protocol consisted of two steps: in the first step, voxel-based CBCT mandible superimposition was performed; the reference comprised the external portion of the symphysis, extending to the first molar. The laser-scanned dental model image was then integrated with the CBCT image to achieve mandibular dental model superimposition. The entire process required approximately 10 minutes. Six landmarks were assigned to the teeth to measure tooth displacement, using tooth displacement on the superimposed laser-scanned mandibles as the reference standard. Accuracy was evaluated by comparing differences in tooth displacement based on the method and the reference standard. Two observers performed superimposition to evaluate reliability. Results: For three-dimensional tooth displacements, the differences between the method and the reference standard were not significant in the molar, premolar, or incisor groups (p > 0.05). The intraclass correlation coefficients for the inter- and intra-observer reliabilities of all measurements were > 0.92. Conclusions: Our method of mandibular dental model superimposition based on voxel registration is accurate, reliable, and can be performed within a reasonable period of time in vitro, demonstrating a potential for use in orthodontic patients.

• 대한치과의사협회지
• /
• 제42권1호통권416호
• /
• pp.7-14
• /
• 2004

Molar extrusion is a quite common problem in prosthodontic patients. It is caused due to the loss or infraocclusion of opposing teeth. A more conservative approach than reduction of the coronal part of extruded tooth is to intrude the malaligned molar orthodontically. Several authors have presented the cases of molar intrusion, by cither removable or fixed appliances. However, the design of those appliances was complex so that many teeth were included as an anchorage unit. This increased the patient's discomfort inevitably. Moreover, the results could be unpredictable. Instead of these conventional methods, skeletal anchorage has been suggested for ideal force system to intrude a molar without any side effects. Many recent clinical reports presented the cases using microscrew or miniplate as a direct anchorage, which included some limitation. The purpose of this report is to introduce the indirect skeletal anchorage for intrusion of extruded maxillary molar.

• 한국식품위생안전성학회지
• /
• 제14권1호
• /
• pp.22-26
• /
• 1999

The purpose of this experiment was to examine the antimicrobial effect of the natural flavonoid hesperidin on dental caries and alveolar bone resorption in the albinorats. Twenty five day old male rats were fed with the experimental diets for 42 days. At the end of the 42 day experimental period, the molar tooth occlusal surface was examined by a dissecting microscope. The sulcular caries lesions were recorded: the first molar caries incidence was higher than that of the second molar and the third molar. Alvelolar bone resorption was measured on the buccal and lingual aspects of each molars. Three measurements were taken on the first molar (mesialpoint, midpoint, distalpoint). The results of this experiments, showed that hesperidin is effective in reducing dental caries and alveolar bone resorption.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제35권2호
• /
• pp.112-119
• /
• 2009

Extracellular matrix(ECM) is known to function as a reservoir of endogenous growth factors, can be an effective delivery system of growth factor that easily lost bioactivity in solution. Fibrillar collagens like type I collagen, are the major constituent of the ECM and structural protein of bone. Also, it can be a scaffold for osteoblast migration. The purpose of this study was to compare the effects of absorbable Atelo-collagen Sponge($Teruplug^{(R)}$) insertion in tooth extraction sites on periodontal healing of the mandibular second molar after the extraction of the impacted third molar. The study population comprised 31 cases who had been scheduled for surgical removal of impacted mandibular third molars. All patients were in good general health and were not using any medication that would influence wound healing after surgery. In 15 cases control group, none was inserted into the tooth extraction site. In 16 cases experimental groups, $Teruplug^{(R)}$ was inserted into the tooth extraction site. We evaluated tooth mobility, pocket depth, gingival margin level preoperatively and 1 week, 2 weeks, 4 weeks, and 3 months postoperatively. The change was compared with two groups using Mann-Whitney test. The results were as follows. 1. There was no significant change of tooth mobility on both groups. 2. There was tendency of decreasing of previous pocket depth causing tooth extraction on both groups. 3. On gingival margin level, there was various change according to initial swelling and loss of attachment on both groups. 4. There was tendency of decreasing of gingival margin level on both groups because of removal of inflammation and decreasing of previous pocket depth. 5. There was large change of pocket depth on buccal middle, distal, lingual distal area because of tooth extraction and bone reduction. Compared with the control group and experimental group, we observed significant difference during some periods. The results of this study suggest that absorbable atelo-collagen sponge($Teruplug^{(R)}$) is relatively favorable bone void filler with prevention of tissue collapse, food packing and enhance periodontal healing.

• 대한치과교정학회지
• /
• 제51권6호
• /
• pp.366-374
• /
• 2021

Objective: This study investigated the impact of a single piezocision in the maxillary alveolar process on the speed of tooth movement. The null hypothesis was that the speed of tooth movement will be equal with and without piezocision. Methods: All maxillary molars on one side were moved against the combined incisors in 10 ten-week-old male Wistar rats. Under general anesthesia, a force of 25 cN was applied on either side using a Sentalloy closed coil spring. After placing the orthodontic appliance, vertical corticision was performed using a piezotome under local anesthesia, 2 mm mesial from the mesial root of the first molar on a randomly selected side; the other side served as the control. At the beginning of the treatment, and 2 and 4 weeks later, skull micro-computed tomography was performed. After image reconstruction, the distance between the mesial root of the first molar and the incisive canal, and the length of the mesial root of the first maxillary molar were measured. Moreover, the root resorption score was determined as described by Lu et al. Results: Significantly higher speed of tooth movement was observed on the corticision side; thus, the null hypothesis was rejected. The loss of root length and root resorption score were significantly more pronounced after piezocision than before. A strong correlation was observed between the speed of tooth movement and root resorption on the surgical side, but the control side only showed a weak correlation. Conclusions: Piezocision accelerates orthodontic tooth movement and causes increased root resorption.