• The Journal of Korean Academy of Prosthodontics
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• v.50 no.3
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• pp.149-155
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• 2012

Purpose: The purpose of this study was to investigate the influence of mobilization on bone-implant interface prior to osseointegration of fixtures. Materials and methods: The experimental implants (3.75 mm in diameter, 4.0 mm in length) were made of commercially pure (Grade IV) titanium, and were treated with RBM ($MegaGen^{(R)}$: Ca-P). The 80 implants (two in each tibia) were inserted into the monocortical tibias of 20 rabbits which each weighed more than 3.5 kg (Female, New Zealand White). According to the removal torque interval, the groups were divided into 10 groups, Group I (6 wks), Group II (4 days+6 wks), Group III (4 days+1 wk+6 wks), Group IV (1 wk+6 wks), Group V (1 wk+1 wk+6 wks), Group VI (2 wks+6 wks), Group VII (2 wks+ 1 wk+6 wk), Group VIII (3 wks+6 wks), Group IX (3 wks+1 wk+6 wks) and Group X (10 wks). The control groups were Group I and X, the removal torque was measured at 6 wks and 10 wks with a digital torque gauge (Mark-10, USA). In the experimental groups, the removal torque was given once or twice before the final removal torque and the value was measured each time. After which, the implants were put back where they had been except the control groups. All the experimental groups were given a final healing time (6 wks) before the final removal torque test, in which values were compared with the control groups and the 1st and/or 2nd removal torque values in each experimental group. Results: In the final removal torque tests, the removal torque value of Group X (10 wks) was higher than that of Group I (6 wks) in the control groups but not statistically different. There were no significant differences between the experimental groups and control groups (P>.05). In the first removal torque comparison, the experimental groups (4 days or 1 wk) values were significantly lower than the other experimental groups (2 wks or 3 wks). In the comparison of each experimental group according to healing time, the final removal torque value was significantly higher than the 1st torque test value. Conclusion: Once or twice mobilization of fixture prior to osseointegration did not deter the final bone to implant osseointegration, if sufficient healing time was given.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.4
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• pp.381-395
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• 2008

Purpoose: For decades dental implants have been used widely in the field of prosthetic dentistry. However there is confusion when establishing treatment plans in cases where some teeth are remained but an insufficient number of implants can be used due to limited anatomical status and ecomomical problems. Many clinicians have tried to connect natural teeth and implants, and it still has controversy. But, there have been few studies on mechanical analysis of connecting natural teeth and implants with konus telescopic removable partial dentures. The purpose of this study was to analyze the stress distribution of prosthesis, abutment and alveolar bone when teeth and implants were connected with the konus telescopic denture, by means of 3-dimensional finite element analysis. Material and methods: The assumption of this study was that there were 2 mandibular canine (11 mm in length, 4 mm in diameter) and 2 implants(10 mm in length, 4 mm in diameter) which are located in the second premolar region. The mandible, teeth, implants, abutments, and connectors are modeled, and analyzed with the commercial software, ANSYS Version 8.1(Swanson, Inc., USA). The control group used implants instead of natural teeth. 21038 elements, 23544 nodes were used in experimental group and 107595 elements, 21963 nodes were used in control group, Stress distribution was evaluated under 150 N vertical load on 3 experimental conditions - between teeth and implants (Load case 1), posterior to implants (Load case 2), between natural teeth (Load case 3). Results: 1. In all load cases, higher von mises stress value was observed in the experimental group. 2. Maximum von miss stress observed in all load cases and all locations were as follows ; a. 929.44 Mpa in the experimental group, 640.044 Mpa in the control group in outer crown and connector - The experimental group showed 1.45 times high value compared with the control group. b. 145,051 Mpa in the experimental group, 142.338 Mpa in the control group in abutment - The experimental group showed 1.02times high value compared with the control group. c. 32.489 Mpa in the experimental group, 25.765 Mpa in the control group in alveolar bone - The experimental group showed 1.26times higher value compared with the control group. 3. All maximum von mises stress was observed in load case 2, and maxim von mises stress in alveolar bone was 32.489 Mpa at which implant failure cannot occur. 4. If maximum von mises stress is compared between two groups, the value of the experimental group is 1.02 times higher than the control group in abutment, 1.26 times higher than the control group in alveolar bone. Conclusion: If natural teeth and implants are connected with the konus telescopic denture, maximum stress will be similar in abutment, 1.26 times higher in alveolar bone than the control group. With this result, there may be possible to make to avoid konus telescopic dentures where natural teeth and implants exist together.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.2
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• pp.105-110
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• 2015

Purpose: The purpose of this study was to evaluate the 3 dimensional accuracy of impression taking on the newly developed healing abutment and impression coping combined system comparing conventional pick-up type impression. Materials and methods: For 10 patients who had a single missing tooth on molar area, dental implants (SuperLine; Dentium, Seoul, Korea) were placed and healing abutment (MyHealing; Raphabio Co., Seoul, Korea) abutments were connected. After 3 months, transfer type impression with MyHealing and pick-up type impression with impression coping were performed twice in the same patients, and master models were fabricated. Customized prosthetic abutments (Myplant; Raphabio Co., Seoul, Korea) were milled and connected to the master casts. Through a dental scanner (Scanner S600; Zirkonzahn, South Tyrol, Italy), the master casts were converted into virtual casts. The length and angulation differences between casts were measured using 3 dimentional analysis program (Geomagic Qualify 12; Geomagic, Morrisville, NC, USA). Statistical significance was calculated using Kruskal Wallis test and Mann-Whitney U test (${\alpha}$=.05). Results: The length differences between the two systems were 0.032 mm in sagittal plane, and 0.029 in coronal plane, and 0.023 mm in horizontal plane. The angulation differences were $0.755^{\circ}$ in sagittal plane, and $1.275^{\circ}$ in coronal plane, and $0.420^{\circ}$ in horizontal plane. Conclusion: The accuracy of newly developed healing abutment system is similar to that of conventional pick-up impression. The new system can reduces chair time by not using separate impression coping.

• The korean journal of orthodontics
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• v.35 no.1 s.108
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• pp.35-42
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• 2005

There is lack of data for the amount of vertical bone in the midpalatal region for miniscrew implantation. The purpose of this study was to measure the structure of the midpalatal suture area using CT image and V-works 4.0 program (Cybermed Inc, Seoul, Korea). CT images of 14 male and 14 female adults were reconstructed. In detail, it was 1) to measure the length of maxilla on the midsagittal plane 2) to measure vertical bone height in the midpalatal area 3) to establish the zone of safety for miniscrew implantation. The following results were obtained. The mean length of ANS-PNS was 51.08mm in males and 47.34mm in females. There was a statistically significant difference between males and females (p<0.05). The vertical bone height of the midpalatal suture area was above 0mm except for 6mm posterior from the central Point of ANS-PNS in males The zone of safety was located 19.43mm posterior from the ANS in males while it was 17.62mm in females along the palatal plane. These results support that the safety zone of the midpalatal area is suitable for screw implantation. Midpalatal miniscrew implantation is a powerful tool in modern orthodontics Through many applications. it can expand the modern orthodontic field.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.228-239
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• 2007

Statement of problem: Following tooth loss, the edentulous alveolar process of maxilla is affected by irreversible reabsorption process, with progressive sinus pneumatization leads to leaving inadquate bone height for placement of endosseous implants. Grafting the floor of maxillary sinus by sinus lifting surgery and augmentation of autologous bone or alternative bone material is a method of attaining sufficient bone height for maxillary implants placement and has proven to be a highty successful. Purpose: This study was undertaken to clarify the morphometric characteristics of inferior maxillary sinus and alveolar process for installation of implants. Material and method: Nineteen skulls (37 sinuses, 10M / 9F) obtained from the collection of the department of anatomy and cell biology of Hanyang medical school were studied. The mean age of the deceased was 69.9 years (range 44 to 88 years). The distance between alveolar border and inferior sinus margin at each tooth, the height of alveolar process and the thickness of cortical bone of the outer and inner table of alveolar process and the inferior wall of maxillary sinus were measured. Results and Conclusion: 1. The septum of inferior maxillary sinus were observe 28 sides (76.%) and located at the third molar (52.6%) and the second molar (26.3%). The deepest points of inferior border of maxillary sinus were located the first or second molar. The distance between alveolar margin and the deepest point of inferior maxillary sinus is $9.7{\pm}4.9mm$. 2. The length of the outer table of alveolar process were $4.9\sim28.2mm$ and the shortest point was between the first and the second molors. The thickness of them were $0.9\sim3.2mm$. The length of the inner table of alveolar process were $7.4\sim25.8mm$ and the shortest point was between the first and the second molars. The thickness of the were $0.9\sim4.6mm$. The results of this study are useful anatomical data for installing of maxillary implants.

• Journal of Periodontal and Implant Science
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• v.34 no.2
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• pp.281-292
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• 2004

Periodontal defects of the furcation are characterized by several inherent anatomic factors that can make successful periodontal therapy difficult and results unpredictable. The severity and rate of occurrence of periodontal disease are directly related to the location of the furcation relative to the cementa-enamel junction and anatomical form of the root by limiting the accessibility and effectiveness of the periodontal instrumentation. This study investigated the reliability and accuracy of panoramic radiograph diagnoses of the periodontal state of mandibular molars, particularly regarding the diagnosis of furcation area periodontal defects, treatment planning, and prognosis prediction. This study examined a total of 110 teeth belonging to 33 subjects (19 male, 14 female) presenting with incipient to moderate periodontitis 4-7mmpocket depth. The alveolar bone level, length and width of the root trunk, and root separation angle were measured using the panoramic radiograph and compared to the results taken directly by retracting a full-thickness flap. The results of the study are as follows: 1. Data regarding the alveolar bone level of the mandibular first molar showed that the directly taken surgical measurements resulted in $5.1{\pm}0.9mm$ that was slightly deeper than the corresponding panoramic measurement resulted in $4.8{\pm}0.8mm$, but these differences were statistically insignificant (p>0.05). 2. The data of the directly taken surgical measurement of the mandibular second molar $(5.1{\pm}1.1mm)$ was slightly deeper than the corresponding panoramic measurement $(4.7{\pm}1.2mm)$, but these differences were statistically insignificant (p>0.05). 3. The measured values of the length and width of the mandibular first molar root trunks were determined to be $4.1{\pm}0.6mm$ and $7.3{\pm}0.9mm$, respectively, while the values of the mandibular second molar root trunks were determined to be $4.6{\pm}1.3mm$ and $7.6{\pm}0.9mm$ respectively. The differences between these values were found to be statistically significant (p<0.01). 4. The measured values of the root separation angle showed that the mandibular first molars averaged $34.5{\pm}4.4^{\circ}$, while the mandibular second molars averaged $23.0{\pm}10.0^{\circ}$. The differences between these values were found to be statistically significant (p<0.01).

• Clinics in Shoulder and Elbow
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• v.15 no.1
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• pp.32-36
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• 2012

Purpose: The purpose of this study was to evaluate the radiologic and clinical outcomes after intercalary tricortical iliac bone graft with plate fixation for the nonunion of midshaft clavicular fractures. Material and Methods: Between September 2007 and May 2011, 10 patients who were treated by the intercalary tricortical iliac bone graft, with plate fixation for clavicle nonunion, were studied. The mean follow-up period was 30.7 (12~57) months. After the sclerotic bone was excised to the bleeding cortical bone, we interposed the tricortical iliac bone to provide structural support and restore clavicle length, and then fixed the plate and screws. The radiologic outcomes on the serial plain radiographs and clinical outcomes, according to UCLA, ASES and Quick DASH scores, were analyzed. Results: Bony union was obtained in all cases (100%) and the average union time was 18.4 (14~24) weeks. The average respective UCLA and ASES scores improved from 16.7 and 52.1 preoperatively to 27.4 and 83.6 postoperatively (p<0.05). The average Quick DASH score was 40.5, at the final follow-up. Complications were 2 shoulder stiffness, and one case had removal of device and arthroscopic surgery at 11 months, postoperatively. There were no implant failure or infection. Conclusion: Intercalary tricortical iliac bone graft, with plate fixation for the nonunion of midshaft clavicular fractures, is a good option that can provide structural support and restore clavicle length, as well as high union rate.

• Journal of Periodontal and Implant Science
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• v.26 no.1
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• pp.255-265
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• 1996

The purpose of the present study is to evaluate dimensional consistency, bristle finishes and bristle rebound rate of four brands of $Dentichek^{(R)}$ toothbrushes(regular-male, regular-female, soft-male, soft-female) to provide referneces in product enhancement and quality control for the manufacturer and to provide suggestions in selecting appropriate toothbrushes for general public. The results are as follows : 1. The size of the head is : $25.10{\times}8.10mm$ for male toothbrushes and $19.90{\times}8.10mm$ for male toothbrushes, while the size of the bristle portion is: $29.90{\times}10.65mm$ for male toothbrushes and $25.25{\times}10.65mm$ for female toothbrushes. 2. The length of the bristles is 10.70mm in all four groups. 3. The length of the toothbrush is 192mm in all four groups. 4. The number of tuft is 43 for male toothbrushes and 35 for female toothbrushes. Tuft arrangement is 4-row configuration in all four groups. 5. The number of bristles in a tuft ranges from 40-56, with higher numbers in male toothbrushes compared to the female counterparts, and higher numbers in the "soft" variety compared to the regular ones. 6. The diameter of the bristle is : 0.21mm for the outer row and 0.19mm for the inner row in the regular brand, and 0.17mm for the soft brand. 7. Irregularly finished bristle ends comprised 20-22% of the total bristles. 8. The bristle rebound rate ranges from 55.9% to 62.3%, with higher numbers in the "soft" variety compared to the regular ones. The above results show that $Dentichek^{(R)}$ toothbrushes meet the requirements of Korean Dental Association standards for toothbrushes, but further evaluations of their effects on periodontium and plaque elimination in actual in-use situation may be needed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.6
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• pp.263-268
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• 2013

Objectives: The interforminal region, between the mandibular foramen, is known as a relatively safe area that is free of anatomic structures, such as inferior alveolar nerve, submandibular fossa, and lingual side of the mandible is occasionally neglected for its low clinical importance. Even in the case of a severely constricted alveolus, perforation of the lingual cortical bone had been intended. However, anterior extension of the inferior alveolar canal, important anatomic structure, such as concavity of lingual bone, lingual foramina, and lingual canal, has recently been reported through various studies, and untypical bleeding by perforation of the lingual plate on implantation has also been reported. Therefore, in this study, we performed radiographic and statistical analysis on distribution and appearance frequencies of the lingual foramina that causes perforation of the mandibular lingual cortical bone to prevent complications, such as untypical bleeding, during surgical procedure. Materials and Methods: We measured the horizontal length from a midline of the mandible to the lingual foramina, as well as the horizontal length from the alveolar crest to the lingual foramina and from the lingual foramina to the mandibular border by multi-detector computed tomography of 187 patients, who visited Dankook University Dental Hospital for various reasons from January 1, 2008 to August 31, 2012. Results: From a total of 187 human mandibles, 110 (58.8%) mandibles had lingual foramina; 39 (20.9%) had bilateral lingual foramen; 34 (18.2%) had the only left lingual foramen; and 37 (19.8%) had the only right lingual foramen. Conclusion: When there is consistent bleeding during a surgical procedure, clinicians must consider damages on the branches of the sublingual artery, which penetrate the lingual foramina. Also, when there is a lingual foramina larger than 1 mm in diameter on a pre-implantation computed tomography, clinicians must beware of vessel damage. In order to prevent these complications and progress with a safe surgical procedure, a thorough radiographic examination before the surgery is indispensable. Further, clinicians should retract lingual flap definitely to confirm the shape of the lingual bone and existence of the lingual foramina.

• Journal of Periodontal and Implant Science
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• v.27 no.3
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• pp.621-631
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• 1997

To verify the effect of subgingival calculus on the periodontal tissues in periodontitis and the effectiveness of supragingival scaling to remove the calculus, 30 teeth from healthy group (Probing pocket depth:$PPD{\leq}mm$: HP group), 15 teeth from moderate group ($4{\leq}PD<7mm$:MP group), 30 teeth from advanced group (PPD>7mm: AP group) were selected and supragingival scaling was performed before extraction of all experimental teeth. After careful extraction, the teeth were cleaned with saline and disclosed with toluidine blue and carefully examined the relationship and distance between the calculus attached on the root surface and periodontal tissues. As a result, it was; 1. The calculus was not discovered on the root surface of teeth in HP group, but was in MP and AP group, mostly on interproximal surface and furca area. The shape of the attached calculus was ovoid, trepazoid and polygonal and the calculus was distributed randomly over the root surface. 2. PPD was more than the distance between the gingival margin to the level of attached connective tissue in AP group rather than in HP and MP group. 3. The length of calculus was $2.7mm{\pm}.44mm$ in HP group and $4.1{\pm}.89in$ AP group. 4. The distance between the apical margin of calculus and the level of attached connective tissue was $2.4{\pm}.33mm$ in MP group and $3.4{\pm}.89mm$ in AP group. 5. The length of subgingival calculus was tended to increase in relation to the probing pocket depth. Therefore, it can be concluded, the calculus in periodontal pocket can not be removed completely with supragingival scaling. As the terminal part of calculus was far away with limited distance from the periodontal tissue, it can be said that the calculus was not a direct factor in destroying the periodontal tissue. In this study, the extent of the plaque was not verified but the location of calculus can be used in clinical practice for complete removal of calculus when the distance relation bewteen calculus and plaque will be known.