• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.4
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• pp.272-281
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• 2020

Agenesis of permanent tooth in adolescent patients can be treated either by orthodontic treatment for space closure or by maintaining the space until implant restoration can be carried out in adult. However, gradual atrophy of alveolar bone width makes it difficult to restore the prosthesis in the future or may cause unaesthetic results. Therefore, maintaining of not only the missing space but also the alveolar bone width should be considered. This case is a treatment whereby a temporary replacement of missing 2 mandibular incisors in adolescent patient was carried out using 2 temporary anchorage devices (TADs). Two TADs were placed horizontally 2 - 3 mm below the top of alveolar ridge, and fixed with artificial teeth by stainless steel wires extended. During the 2 year follow-up, neither gingival inflammation nor loss of the TADs have occurred. In the radiographic evaluation, the growth of the adjacent alveolar bone was not inhibited, and the width of the alveolar bone was maintained.

• Journal of Korean Dental Science
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• v.15 no.1
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• pp.1-8
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• 2022

Purpose: Intraoral scanners, desktop scanners, and cone-beam computed tomography (CBCT) are being used in a complementary way for diagnosis and treatment planning. Limited patient-based results are available about dimensional reproducibility among different three-dimensional imaging systems. This study aimed to evaluate dimensional reproducibility among patient-derived digital models created from an intraoral scanner, desktop scanner, and two CBCT systems. Materials and Methods: Twenty-nine arches from sixteen patients who were candidates for implant treatments were enrolled. Different types of CBCT systems (KCT and VCT) were used before and after the surgery. Polyvinylsiloxane impressions were taken on the enrolled arches after the healing period. Gypsum casts were fabricated and scanned with an intraoral scanner (CIOS) and desktop scanner (MDS). Four test groups of digital models, each from CIOS, MDS, KCT, and VCT, respectively, were compared to the reference gypsum cast group. For comparison of linear measurements, intercanine and intermolar widths and left and right canine to molar lengths were measured on individual gypsum cast and digital models. All measurements were triplicated, and the averages were used for statistics. Bland-Altman plots were drawn to assess the degree of agreement between each test group with the reference gypsum cast group. A linear mixed model was used to analyze the fixed effect of the test groups compared to the reference group (α=0.05). Result: The Bland-Altman plots showed that the bias of each test group was -0.07 mm for CIOS, -0.07 mm for MDS, -0.21 mm for VCT, and -0.25 mm for KCT. The linear mixed model did not show significant differences between the test and reference groups (P>0.05). Conclusion: The linear distances measured on the digital models created from CIOS, MDS, and two CBCT systems showed slightly larger than the references but clinically acceptable reproducibility for diagnosis and treatment planning.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.4
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• pp.395-403
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• 2022

In the fracture operation of pan facial fracture, there are many cases where the shape and position of the occlusal and oral structures are abnormally changed because the index for repositioning to the original position is insufficient. And trismus and gag reflex in patients with pan facial fractures increase the difficulty of dental treatment, and the difference in the position of the jaw bone makes it difficult to restore aesthetically and functionally. In this case, digital workflows for minimal intraoral work could be selected to reduce patient discomfort and the difficulty of dental treatment. This case is using a digital workflow from implant planning to final prosthesis production in a patient with acquired skeletal grade III, trismus, and gag reflex due to pan facial fracture 15 years ago. In this case report, the use of digital workflow in a patient who has difficulty in dental treatment was able to minimize patient discomfort and obtain esthetic and functionally appropriate results.

• Journal of Periodontal and Implant Science
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• v.51 no.6
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• pp.398-408
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• 2021

Purpose: In this study, we aimed to evaluate the clinical validity of the modified tunneling technique using minimal soft tissue harvesting and volume-stable collagen matrix in the anterior mandible. Methods: In total, 27 anterior mandibular teeth and palatal donor sites in 17 patients with ≥1 mm of gingival recession (GR) were analyzed before and after root coverage. For the recipient sites, vertical vestibular incisions were made in the interdental area and a subperiosteal tunnel was created with an elevator. After both sides of the marginal gingiva were tied to one another, a prepared connective tissue graft and volume-stable collagen matrix were inserted through the vestibular vertical incision and were fixed with resorbable suture material. The root coverage results of the recipient site were measured at baseline (T₀), 3 weeks (T₃), 12 weeks (T₁₂), and the latest visit (T_l). For palatal donor sites, a free gingival graft from a pre-decided area avoiding the main trunk of the greater palatine artery was harvested using a prefabricated surgical template at a depth of 2 mm after de-epithelization using a rotating bur. In each patient, the clinical and volumetric changes at the donor sites between T₀ and T₃ were measured. Results: During an average follow-up of 14.5 months, teeth with denuded root lengths of 1-3 mm (n=12), 3-6 mm (n=11), and >6 mm (n=2) achieved root coverage of 97.01%±7.65%, 86.70%±5.66%, and 82.53%±1.39%, respectively. Miller classification I (n=12), II (n=10), and III (n=3) teeth showed mean coverage rates of 97.01%±7.65%, 86.91%±5.90%, and 83.19%±1.62%, respectively. At the donor sites, an average defect depth of 1.41 mm (70.5%) recovered in 3 weeks, and the wounds were epithelized completely in all cases. Conclusions: The modified tunneling technique in this study is a promising treatment modality for overcoming GR in the anterior mandible.

• The Journal of Korean Academy of Prosthodontics
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• v.61 no.4
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• pp.308-315
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• 2023

In the case of a patients who have lost the centric stop and have a staggered occlusion of the residual teeth, various movements occur when the denture is loaded. Implant placement is necessary to reinforce the retention, support, and stabilization elements to reduce denture movement. However, in this case, considering the patient's age, aversion to surgery, and bone loss, implants were not placed and restoration was performed with a removable partial denture. In this case, it is important to set the correct mandibular position for restoration because the patient has a habit of chewing with the remaining teeth. In this case, a stable mandibular position was established using a gothic arch tracing, and good results were obtained by restoring with partial dentures, so this is reported.

• The Transactions of the Korea Information Processing Society
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• v.13 no.7
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• pp.326-334
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• 2024

Extra-oral imaging techniques such as Panoramic X-rays (PXs) and Cone Beam Computed Tomography (CBCT) are the most preferred imaging modalities in dental clinics owing to its patient convenience during imaging as well as their ability to visualize entire teeth information. PXs are preferred for routine clinical treatments and CBCTs for complex surgeries and implant treatments. However, PXs are limited by the lack of third dimensional spatial information whereas CBCTs inflict high radiation exposure to patient. When a PX is already available, it is beneficial to reconstruct the 3D oral structure from the PX to avoid further expenses and radiation dose. In this paper, we propose 3DentAI - an U-Net based deep learning framework for 3D reconstruction of oral structure from a PX image. Our framework consists of three module - a reconstruction module based on attention U-Net for estimating depth from a PX image, a realignment module for aligning the predicted flattened volume to the shape of jaw using a predefined focal trough and ray data, and lastly a refinement module based on 3D U-Net for interpolating the missing information to obtain a smooth representation of oral cavity. Synthetic PXs obtained from CBCT by ray tracing and rendering were used to train the networks without the need of paired PX and CBCT datasets. Our method, trained and tested on a diverse datasets of 600 patients, achieved superior performance to GAN-based models even with low computational complexity.

• Journal of Oral Medicine and Pain
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• v.30 no.2
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• pp.163-199
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• 2005

Dentistry had been considered to be a relatively safe zone from the risk of medical accidents for there are less number of emergency cases. However, in these days, the number of medical dispute is increasing that the dentists would not be able to overlook it as if it is none of their matters. Hence, researches on various medical accidents and analyses on related matters to seek proper management have been carried out recently, but the datas are not enough yet. This study analysed the actual conditions of medical accidents as well as disputes and the general awareness of dental practitioners in local clinics with the purpose of understanding the general situation and to suggest counterplan. The study was conducted by analysing 1,882 questionnaires collected from total of 3,684 dentists belonging to Seoul Dental Association and where Doctors and Hospitals Medical Malpractice Insurance for dentists is administered. The results were as follows: 1. 98.47% of the respondents doubted the risk of medical accident and dispute. 2. 27.42% of the respondents experienced medical dispute, and there was no significant difference between the rate of medical disputes and the resident training. 3. Among the cases of medical accidents, those related to the periodontal/operative treatment showed the highest rate of 20.50%, and that related to implant treatment was 6.17%. 4. 43.02% of the respondents explained about the treatment procedure before the treatment while 25.90% started the treatment without consent of the patients. 5. Medical dispute resulted from not having any explanation or consent of the patients were of 16.55%. 10.26% had difficulties in solving the problem for missing the medical records. 6. 49.73% responded to be capable of administering first aid treatment. Among them, 23.60% were equipped with accurate knowledge regarding the emergency care. 7. During medical dispute, 88.09% sought counsel from other dentists, and Local district dental association was found to be the most frequently asked group. 8. In cases of medical dispute, 5.26% of the respondents were asked to submit relevant data from customer protection organization, and among them, 75.61% acceded the demand sincerely. 9. After the settlement of the dispute, 83.63% recovered relatively stable state of mind. 10. 99.46% of the respondents felt the necessity of medical dispute management organization, and 78.58% responded that it was urgent. 11. 66.70% of the respondents joined Doctors and Hospitals Medical Malpractice Insurance, although they had not experienced medical dispute. However, 73.36% of the respondent were not aware of it, and 93.36% of the members were not aware of the procedure of the dispute settlement. 12. 79.0% of the respondents who joined the Doctors and Hospitals Medical Malpractice Insurance still felt confused when medical dispute occured, but relatively safer than before. 13. When medical dispute was settled through Doctors and Hospitals Medical Malpractice Insurance, 71.92% of the dentists were contented more than moderately, however, 35.16% of the patients were contented. 14. For complement of Doctors and Hospitals Medical Malpractice Insurance, 53.22% of the respondents felt that insurance company, dentist, and patient should all participate in bringing mutual agreement for quick settlement of the dispute. In addition, 29.08% of the respondents wanted insurance company to prevent patients from disturbing their practices. From the above results, improvement of the general awareness on increasing rate of medical disputes, and education as well as complementary measures for settlement of the disputes are required.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.659-678
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• 1998

In the present study, oligonucleotide probes based on 16S rRNA were taken to investigate the diversity of oral spirochetes without culture method. This is the first study that revealed oral spirochetes of both presently cultivable and uncultured oral spirochetes in Korean adult periodontitis patients. Subgingival plaque samples were taken from diseased sites(probing depth ${\geq}6\;mm$, experimental group, n=116) and healthy sites(probing depth${\leq}3mm$, control 1 group, n=28) in 29 patients with adult periodontitis, and from 20 periodontally healthy subjects(probing depth${\leq}3mm$, control 2 group, n=100). Following being examined under phase-contrast microscope, all samples were submitted to dot-blot hybridization after polymerase chain reacton with eubacterial primers. 5 species-specific probes(TVIN, TDEN, TMAL, TSOC, and TPEC) and 7 group-specific probes(TRE I, TRE II, TRE III, TRE IV, TRE V, TRE VI, and TRE VII) were used one by one for the identification of both cultivable and so far uncultivable oral spirochetes. All probes were labeled with digoxigenin(DIG)-ddUTP and detected by chemilumininescence. The following results were obtained. 1. Under phase-contrast microscope, 91.37% and 14.28% of oral spirochetes were observed in the experimental and control 1 groups, respectively. None of oral spirochetes were observed in control 2 group. 2. With universal probe, 98.27%, 46.42%, and 22.0% of oral spirochetes were observed in experimental, control 1, and control 2 groups, respectively. 3. With specific probe, 95.68%, 35.71%, and 19.0% of oral spirochetes were observed in experimental, control 1, and control 2 groups, respectively. 4. With species-specific probes, T. socranskii were recovered in a high percentage of sites(81.89%) examined, followed by T. maltophilum(50.0%), T. vincentii(36.20%), T. denticola(13.79%), respectively. With group- specific probes, TRE IV was recovered in a high percentage of sites(85.34%) examined, followed by TRE II(77.58%), TRE I(56.89%), TRE III(25.86%), TRE VI(5.17%), and TRE V(2.58%), respectively. 5. T. vincentii were only observed in the diseased sites, not in the healthy sites. 6. Neither T. pectinovorum nor group VII oral spirochetes were observed in any sites. The findings warrant further investgations of the recovered spirochetes to elucidate the possible associations of oral spirochetal prevalence in race and types of periodontitis, pathogenesis of T. vincentii and the possible distributional change of oral spirochetes before and after treatments.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.989-1002
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• 1996

The purpose of this study was to determine the effect of a pulsed Nd:YAG laser irradiation on human gingival tissues. The patients, who were planned to be treated by clinical crown lengthening procedure and gingivectomy, were selected. All the patients received oral hygiene instruction, scaling and root planing at preoperation. The crest of gingival tissue on upper and lower anterior teeth was irradiated by a pulsed Nd:YAG laser(El. EN. EN060, Italy) with a fiber optic of 300 m in contact mode for 20 seconds. Gingival tissues were divided into 4 groups according to the laser power of 1.0W(10Hz, 100mJ), 2.0W(20Hz, 100mJ), 3.0W(30Hz, 100mJ) and 4.0W(40Hz, 100mJ). Immediately after the laser irradiation, the specimens were excised, fixed 10% neutral formalin, sectioned $4-6{\mu}m$ thick, stained by Hematoxylin-Eosin and Periodic Acid Schiff stain and observed under light microscope. The removed tissue depth and the coagulated layer depth due to a laser irradiation by a laser irradiation were measured on the microphotographs. The difference of measurements according to the different laser power was statistical1y analyzed by Kruskal Wallis Test with SAS program. The results were as follows : 1. In histologic findings of irradiated gingival tissues; a. In the irradiated gingival specimen with 1.0W laser power, some vesicles were observed in limited superficial layer of gingival epithelium. b. In the irradiated gingival specimen with 2.0W and 3.0W laser power, the epithelium was almost removed except for the traces of viable basal cell remnants at ret peg, and coagulation necrosis related with the thermal effect of laser was noted. c. In the irradiated gingival specimen with 4.0W laser power, complete removal of epithelium, partial removal of underlying connective tissue, and the coagulation necrosis of subjacent gingival tissue were shown. 2. The removed tissue depth was deeper in the irradiated specimens with higher power. There was a statistical significance in the difference of removed tissue depth between 1.0W group ($44.54{\pm}6.99um$) and 3.0W group ($99.75{\pm}6.64{\mu}m$), and between 1.0W group($44.54{\pm}6.99{\mu}m$) and 4.0W group($111.36{\pm}4.50{\mu}m$), and between 2.0W group($98.01{\pm}4.53{\mu}m$) and 4.0W group($111.36{\pm}4.50{\mu}m$)(P<0.05). 3. The coagulated layer depth was deeper in the irradiated specimens with higher power. There was a statistical significance in the difference of coagulated layer depth between 1.0W group($31.82{\pm}8.99{\mu}m$) and 3.0W group($55.99{\pm}20.94{\mu}m$), and between 1.0W group($31.82{\pm}8.99{\mu}m$) and 4.0W group($83.68{\pm}10.34{\mu}m$)(P<0.05). From this study, the results demonstrated that the effects of a pulsed Nd:YAG laser irradiation on gingival tissues seemed to depend on the laser power and that the irradiation with high power could be harmful to adjacent healthy tissue.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5259-5264
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• 2014

Background: CT based brachytherapy allows 3-dimensional (3D) assessment of organs at risk (OAR) doses with dose volume histograms (DVHs). The purpose of this study was to compare computed tomography (CT) based volumetric calculations and International Commission on Radiation Units and Measurements (ICRU) reference-point estimates of radiation doses to the bladder and rectum in patients with carcinoma of the cervix treated with high-dose-rate (HDR) intracavitary brachytherapy (ICBT). Materials and Methods: Between March 2011 and May 2012, 20 patients were treated with 55 fractions of brachytherapy using tandem and ovoids and underwent post-implant CT scans. The external beam radiotherapy (EBRT) dose was 48.6Gy in 27 fractions. HDR brachytherapy was delivered to a dose of 21 Gy in three fractions. The ICRU bladder and rectum point doses along with 4 additional rectal points were recorded. The maximum dose ($D_{Max}$) to rectum was the highest recorded dose at one of these five points. Using the HDRplus 2.6 brachyhtherapy treatment planning system, the bladder and rectum were retrospectively contoured on the 55 CT datasets. The DVHs for rectum and bladder were calculated and the minimum doses to the highest irradiated 2cc area of rectum and bladder were recorded ($D_{2cc}$) for all individual fractions. The mean $D_{2cc}$ of rectum was compared to the means of ICRU rectal point and rectal $D_{Max}$ using the Student's t-test. The mean $D_{2cc}$ of bladder was compared with the mean ICRU bladder point using the same statistical test. The total dose, combining EBRT and HDR brachytherapy, were biologically normalized to the conventional 2 Gy/fraction using the linear-quadratic model. (${\alpha}/{\beta}$ value of 10 Gy for target, 3 Gy for organs at risk). Results: The total prescribed dose was $77.5Gy{\alpha}/{\beta}10$. The mean dose to the rectum was $4.58{\pm}1.22Gy$ for $D_{2cc}$, $3.76{\pm}0.65Gy$ at $D_{ICRU}$ and $4.75{\pm}1.01Gy$ at $D_{Max}$. The mean rectal $D_{2cc}$ dose differed significantly from the mean dose calculated at the ICRU reference point (p<0.005); the mean difference was 0.82 Gy (0.48-1.19Gy). The mean EQD2 was $68.52{\pm}7.24Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$, $61.71{\pm}2.77Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$ and $69.24{\pm}6.02Gy_{{\alpha}/{\beta}3}$ at $D_{Max}$. The mean ratio of $D_{2cc}$ rectum to $D_{ICRU}$ rectum was 1.25 and the mean ratio of $D_{2cc}$ rectum to $D_{Max}$ rectum was 0.98 for all individual fractions. The mean dose to the bladder was $6.00{\pm}1.90Gy$ for $D_{2cc}$ and $5.10{\pm}2.03Gy$ at $D_{ICRU}$. However, the mean $D_{2cc}$ dose did not differ significantly from the mean dose calculated at the ICRU reference point (p=0.307); the mean difference was 0.90 Gy (0.49-1.25Gy). The mean EQD2 was $81.85{\pm}13.03Gy_{{\alpha}/{\beta}3}$ for $D_{2cc}$ and $74.11{\pm}19.39Gy_{{\alpha}/{\beta}3}$ at $D_{ICRU}$. The mean ratio of $D_{2cc}$ bladder to $D_{ICRU}$ bladder was 1.24. In the majority of applications, the maximum dose point was not the ICRU point. On average, the rectum received 77% and bladder received 92% of the prescribed dose. Conclusions: OARs doses assessed by DVH criteria were higher than ICRU point doses. Our data suggest that the estimated dose to the ICRU bladder point may be a reasonable surrogate for the $D_{2cc}$ and rectal $D_{Max}$ for $D_{2cc}$. However, the dose to the ICRU rectal point does not appear to be a reasonable surrogate for the $D_{2cc}$.