• 치과방사선
• /
• 제28권2호
• /
• pp.339-353
• /
• 1998

The purpose of this study was to investigate whether a radiographic estimate of osseous fractal dimension and power spectrum of 2D discrete Fourier transform is useful in the characterization of structural changes in bone. Ten specimens of bone were decalcified in fresh 50 ml solutions of 0.1 N hydrochloric acid solution at cummulative timed periods of 0 and 90 minutes. and radiographed from 0 degree projection angle controlled by intraoral parelleling device. I performed one-dimensional variance. fractal analysis of bony profiles and 2D discrete Fourier transform. The results of this study indicate that variance and fractal dimension of scan line pixel intensities decreased significantly in decalcified groups but Fourier spectral analysis didn't discriminate well between control and decalcified specimens.

• 치과방사선
• /
• 제27권2호
• /
• pp.27-47
• /
• 1997

The purpose of this study was to evaluate the accuracy and usefulness of spiral tomography through the comparison and analysis of SCANORA cross-sectional tomographs and DentaScan computed tomographic images of dry mandibles taken by a SCANORA spiral tomographic machine and a computed tomographic machine. Thirty-one dry mandibles with full or partial edentulous areas were used. To evaluate the possible effect of location in the edentulous area, it was divided into 4 regions of Me (region of mental foramen), MI (the midportion between Me and M2), M2 (the midportion between mental foramen and mandibular foramen) and S (the midportion of the mandibular symphysis). A ZPC column (sized 4 mm x 5 mm) was seated on the edentulous regions of Me, MI, M2 and S using the acrylic stent. Then SCANORA spiral tomography and computed tomography were taken on the edentulous regions which contained the ZPC column. The ZPC columns and cross-sectional images of the mandible were measured in the radiographs by three observers and the differences between the two imaging modalities were analysed. The results were as follows: 1. In comparing the actual measurements of the ZPC column and measurements in the radiographs, the mean error of the DentaScan computed tomography was 0.07 mm in vertical direction and -0.06 mm in horiwntal direction, while the mean error of the SCANORA spiral tomography was 0.06 mm in vertical direction and -0.12 mm in horizontal direction. There was a significant difference between the two radiographic techniques in the horizontal measurement of the ZPC column of the symphysis region (p<0.05). But there was no significant difference in the measurements of other regions (p>0.05). 2. In measurements of the distance from the alveolar crest to the inferior border of the mandible (H), and of the distance from the alveolar crest to the superior border of the mandibular canal (Y), there was no significant difference between the two radiographic techniques (p>0.05). 3. In measurements of the distance from the lingual border of the mandible to the buccal border of the mandible (W), and of the distance from the lingual border of the mandible to the lingual border of the mandibular canal (X), there was a significant difference between the two radiographic techniques in measurements of the midportion between the mental foramen and the mandibular foramen (M2) (p<0.05). But there were no significant differences in measurements of the other regions of symphysis (S), mental foramen (Me), the first one-fourth portion between the mental foramen and the mandibular foramen (M1) (p>0.05). 4. Considering the mean range of measurements between observers, the measurements of SCANORA spiral tomography showed higher value than those of DentaScan computed tomography, except in measurements of symphysis (S). 5. On the detectability of the mandibular canal, there was no significant difference between the two radiographic techniques (p>0.05). In conclusion, SCANORA spiral tomography demonstrated a higher interobserver variance than that of DentaScan computed tomography for implant site measurements in the posterior edentulous area of the mandible. These differences were mainly the result of difficulty in the detection of the border of the mandible in SCANORA spiral tomography. But considering the cost and the radiation exposure, SCANORA spiral tomography can be said to be a relatively good radiographic technique for implant site measurement.

• 한방재활의학과학회지
• /
• 제20권2호
• /
• pp.199-208
• /
• 2010

Objectives : To study the cervical lordosis and roentgenographic analysis of cervical disc space in neck pain with or without temporomandibular disorder(TMD). Methods : Radiographic measures of cervical lordosis, cervical disc space narrowing were collected, statiscally analyzed. Results : TMD group showed a significant increase in cervical lordotic angle as compared with non-TMD group, whereas no significant change in cervical disc degeneration. Conclusions : The findings from this study suggest that the curvature of the cervical spine is related to the subject's TMD.

• Journal of Periodontal and Implant Science
• /
• 제44권1호
• /
• pp.13-19
• /
• 2014

Purpose: The purpose of this study was to retrospectively evaluate the survival of periodontally hopeless teeth that were intentionally extracted and replanted after a delay and to compare the radiographic characteristics of the survival group with those of the failure group. Methods: The clinical and radiographic data from patients who underwent delayed intentional replantation between March 2000 and July 2010 were reviewed. Twenty-seven periodontally hopeless teeth were extracted and preserved in medium supplemented with antibiotics for 10-14 days. The teeth were then repositioned in the partially healed extraction socket and followed for 3 to 21 months. The radiographic parameters were analyzed using a paired t test and the cumulative survival rate was analyzed using Kaplan-Meier analysis. Results: Seven replanted teeth failed and the overall cumulative survival rate was 66.4%. In the survival group, the amount of bone loss was reduced from 68.45% to 34.66% three months after replantation. There was radiologic and clinical evidence of ankylosis with 5 teeth. However, no root resorption was found throughout the follow-up period. In the failure group, bone formation occurred from the bottom of the socket. However, a remarkable radiolucent line along the root of a replanted tooth existed. The line lengthened and thickened as time passed. Finally, in each case of failure, the tooth was extracted due to signs of inflammation and increased mobility. Conclusions: Delayed intentional replantation has many advantages compared to immediate intentional replantation and could serve as an alternative treatment for periodontally involved hopeless teeth. However, techniques for maintaining the vitality of periodontal structures on the tooth surface should be developed for improved and predictable results.

• 대한방사선기술학회지:방사선기술과학
• /
• 제33권3호
• /
• pp.289-294
• /
• 2010

이 연구의 목적은 다결정 요오드화수은 박막검출기를 제작하여 X-선촬영 조사 조건하에서 검출기 성능의 평가이다. 두께 210과 $320 \;{\mu}m$를 갖는 다결정 요오드화수은 박막검출기들은 스크린 프린트 기술로 제작하였다. X-선 감도와 암전류의 측정들은 두 검출기에 대하여 수행하였다. 그리고 X-선 반응의 선형성과 재현성의 측정들은 두께 $320 \;{\mu}m$의 검출기에 대하여 수행하였다. 두께 $320 \;{\mu}m$의 검출기에 인가된 0.05에서 $2\;V/{\mu}m$까지의 전기장 강도들에 대하여, X-선 감도들은 233에서 $1,408{\times}10^6\;electrons/mR{\cdot}mm^2$까지 측정되었다. 그리고 암전류들은 3.2에서 $118\;pA/mm^2$까지 측정되었다. Zhong Su 등에 의해 보고된 값들과 비교에서, X-선 감도들은 Zhong Su 등에 의해 측정된 X-선 감도들보다 약 2배 더 크게 나타냈다. 그리고 암전류들은 Zhong Su 등에 의해 측정된 암전류들보다 약 9배 더 크게 나타냈다. X-선 반응의 선형성은 상관계수(r)로서 0.988을 얻었다. 재현성은 변동계수로서 0.002를 얻었다. 이 연구는 X-선촬영 조사 조건하에서 능동매트릭스 평판영상장치에 사용할 수 있는, 제작된 다결정 요오드화수은 박막검출기의 성능 데이터를 제공한다.

• Journal of Korean Neurosurgical Society
• /
• 제46권4호
• /
• pp.397-402
• /
• 2009

Objective : In this study, the authors assessed the ability of rat bone marrow derived mesenchymal stem cells (BMDMSCs), in the presence of a growth factor, fibroblast growth factor-4 (FGF-4) and hydroxyapatite, to act as a scaffold for posterolateral spinal fusion in a rat model. Methods : Using a rat posterolateral spine fusion model. the experimental study comprised 3 groups. Group 1 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite only. Group 2 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite containing $1{\times}10^6/60{\mu}L$ rat of BMDMSCs. Group 3 was composed of 6 animals that were implanted with 0.08 gram hydroxyapatite containing $1{\times}10^6/60{\mu}L$ of rat BMDMSCs and FGF-4 $1{\mu}G$ to induce the bony differentiation of the BMDMSCs. Rats were assessed using radiographs obtained at 4, 6, and 8 weeks postoperatively. After sacrifice, spines were explanted and assessed by manual palpation, high-resolution microcomputerized tomography, and histological analysis. Results : Radiographic, high-resolution microcomputerized tomographic, and manual palpation revealed spinal fusion in five rats (83%) in Group 2 at 8 weeks. However, in Group 1, three (60%) rats developed fusion at L4-L5 by radiography and two (40%) by manual palpation in radiographic examination. In addition, in Group 3, bone fusion was observed in only 50% of rats by manual palpation and radiographic examination at this time. Conclusion : The present study demonstrates that 0.08 gram of hydroxyapatite with $1{\times}10^6/60{\mu}L$ rat of BMDMSCs induced bone fusion. FGF4, added to differentiate primitive $1{\times}10^6/60{\mu}L$ rat of BMDMSCs did not induce fusion. Based on histologic data, FGF-4 appears to induce fibrotic change rather than differentiation to bone by $1{\times}10^6/60{\mu}L$ rat of BMDMSCs.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제42권3호
• /
• pp.144-150
• /
• 2016

Objectives: We compared the transbuccal and transoral approaches in the management of mandibular angle fractures. Materials and Methods: Sixty patients with mandibular angle fractures were randomly divided into two equal groups (A, transoral approach; group B, transbuccal approach) who received fracture reduction using a single 2.5 mm 4 holed miniplate with a bar using either of the two approaches. Intraoperatively, the surgical time and the ease of surgical assess for fixation were noted. Patients were followed at 1 week, 3 months, and 6 months postoperatively and evaluated clinically for post-surgical complications like scarring, infection, postoperative occlusal discrepancy, malunion, and non-union. Radiographically, the interpretation of fracture reduction was also performed by studying the fracture gap following reduction using orthopantomogram tracing. The data was tabulated and subjected to statistical analysis. A P -value less than 0.05 was considered significant. Results: No significant difference was seen between the two groups for variables like surgical time and ease of fixation. Radiographic interpretation of fracture reduction revealed statistical significance for group B from points B to D as compared to group A. No cases of malunion/non-union were noted. A single case of hypertrophic scar formation was noted in group B at 6 months postsurgery. Infection was noted in 2 patients in group B compared to 6 patients in group A. There was significantly more occlusal discrepancy in group A compared to group B at 1 week postoperatively, but no long standing discrepancy was noted in either group at the 6 months follow-up. Conclusion: The transbuccal approach was superior to the transoral approach with regard to radiographic reduction of the fracture gap, inconspicuous external scarring, and fewer postoperative complications. We preferred the transbuccal approach due to ease of use, minimal requirement for plate bending, and facilitation of plate placement in the neutral mid-point area of the mandible.

• International Journal of Oral Biology
• /
• 제48권3호
• /
• pp.19-31
• /
• 2023

Peri-implantitis is a disease affecting the tissue surrounding dental implants, destroying both soft and hard tissues. A total of 2,015 studies were collected by searching items in the National Library of Medicine, including keywords, such as "peri-implantitis," "microbiota," and "microbiome." Of them, 62 studies were screened and considered eligible for analysis. Only 16 studies qualified all criteria mentioned here: "Using PCR methods for microorganism detection," "Suggesting quantified results," "Stating obvious clinical diagnosis criteria ("Bleeding on probing," "Probing pocket depth," "Suppuration," and "Radiographic bone loss")." Only 8 studies were included in the meta-analysis because the others had special issues. Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Epstein-Barr virus were the microbiological subjects of analysis. The odds ratio (OR) between the healthy implants and peri-implantitis were calculated for each microorganism to compare two groups, and the forest plots were suggested as the visual materials. P. gingivalis (1.392 < OR < 2.841), T. forsythia (1.345 < OR < 3.221), T. denticola (2.180 < OR < 5.150), A. actinomycetemcomitans (1.975 < OR < 6.456), P. intermedia (1.245 < OR < 3.612), and Epstein-Barr virus (1.995 < OR < 9.383). The species showed that their 95% confidence interval of odds ratio was higher than 1, indicating that they were detected more frequently in periimplantitis than in healthy implants. Meanwhile, other species, such as Fusobacterium nucleatum and Staphylococcus aureus, were not included in the meta-analysis because the number of studies was insufficient.

• 치과방사선
• /
• 제21권2호
• /
• pp.261-273
• /
• 1991

This study was undertaken to document and better defined this condition to help clarify this clinical and radiographical appearances by the analysis of clinical and radiographical features of fibro-osseous lesions in the jaws. A study was made of a series of 128 cases with fibro-osseous lesions. The obtained results were as follows. 1. Fibrous dysplasia of the jaws occurred with equal predilection for males and females. But the females occurred in 68% of cemento-ossifying fibroma and 75% of periapical cemental dysplasia. 2. 43% of fibrous dysplasia and 32% of cemento-ossifying fibroma occurred in the 2nd decades and 33% of periapical cemental dysplasia in 5th decades. 3. 62% of fibrous dysplasia occurred in the maxilla, 73% of cemento-ossifying fibroma in mandible, 90% of periapical cemental dysplasia in mandible. 4. 98% of fibrous dysplasia occurred in premolar-molar region, 77% of cemento-ossifying fibroma in molar region, 68% of periapical cemental dysplasia in incisor region. 5. In serial radiographic features, mature stage were 55% of fibrous dysplasia, 45% of cemento-ossifying fibroma, 59% of periapical cemental dysplasia. 6. 87% of fibrous dysplasia had monostotic lesion, 67% of periapical cemental dysplasia had multiple lesions. 7. In fibrous dysplasia and cemento-ossifying fibroma, migration of tooth occurred in 61.7% and 36.4%, retention of tooth occurred in 4.3% and 9.1%, loss of lamina dura occurred in 6.4% and 9.1%, and root resorption had not occurred in fibrous dysplasia, but occurred in 18% of cemento-ossifying fibroma, displacement of mandibular canal occurred in 14.9% and 31.8%.

• 치과방사선
• /
• 제21권2호
• /
• pp.393-403
• /
• 1991

The purpose of this study was to evaluate the incidence and radiographic features of 1,300 cases of supernumerary teeth by means of the analysis of periapical radiograms and/or pantomograms in 69,442 persons visited the Department of Oral Radiology, School of Dentistry, Kyung Hee University during January 1980 to December 1989. This study of supernumerary teeth revealed the following features: 1. The incidence of supernumerary tooth was revealed to be 1.5% in total examined persons, and there was a higher incidence in males (74.0%) than in females (26.0%). 2. The supernumerary teeth were most frequently occurred in the 1 st decade (42.7%), followed by the 2nd decades (20.2%), the 3rd decades (14.1 %), and the 5th decades (7.2%). 3. There was a higher incidence in the maxilla (98.7%) than in the mandible (1.3%), and mesiodens (90.1 %) was the most frequently occurred. The maxillary lateral incisor region (3.1%) was next in order of frequency followed by maxillary distomolar (2.2%), and maxillary paramolar (1.5%). 4. There was a higher incidence of the impaction (82.7%) than that of the eruption (17.3%), and supernumerary tooth in lateral incisor region (87.8%) was the most frequently impacted one. 5. The inverted impaction was occurred in 63.1%, the vertical impaction in 18.1%, and the angulated impaction in 18.8%. In localization, a palatally (lingually) impacted supernumerary tooth was occurred in 85.0%, and middle impacted and buccally (labially) impacted supernumerary tooth showed the same incidence (7.5%). 6. A supplemental tooth was occurred in 3.2%, an accessory tooth in 96.8%, and a supplemental tooth was the most frequently occurred in maxillary lateral incisor and mandibular premolar region. 7. In effects of supernumerary tooth on adjacent tooth, crowding was occurred in 0.4%, diastema in 10.6%, rotation in 5.4%, eruption disturbance in 4.5%, root resorption in 2.5%, and dentigerous cyst in 2.2%.