• Title/Summary/Keyword: Tooth crown

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Interface Phenomena between Prosthodontic Crown and Abutment Sprayed with Die Spacer (Die Spacer가 도포된 보철용 크라운과 어버트먼트의 계면현상)

  • Park, K.H.;Choe, H.C.
    • Journal of Surface Science and Engineering
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    • v.40 no.4
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    • pp.197-202
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    • 2007
  • Fit of the restoration and its cementation procedure is crucial to both its short and long term prognosis. Marginal fit is affected by many variables during the fabrication process. These variables, being intrinsic properties of the materials or the clinical technique used, can cause changes in the size and shape of the definitive restoration. Even if all variables are controlled carefully, the seating of a restoration can still be affected due to insufficient space for the luting agent. The use of die spacer can reduce the elevation of a cast restoration of a prepared tooth, decreased seating time, improve the outflow of excess cement, and lower the seating forces. The purpose of this study was to evaluate the marginal fidelity according to die spacer application times and measurement site. Casting alloys were prepared and fabricated using non-precious metal at $950^{\circ}C$. Specimens are divided into four groups: I(die spacer painted casting for wax pattern), II(die spacer non painted casting for wax pattern). The specimens were cut and polished for marginal gap observation. The marginal gap was observed using scanning electron microscopy (SEM).

Expression and Localization of Keap1 During Amelogenesis in the Developing Molar Germ of Rats

  • Kim, Sun-Hun;You, Yong-Ouk;Ko, Hyun-Mi;Kim, Hyun-Jin
    • International Journal of Oral Biology
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    • v.43 no.4
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    • pp.177-183
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    • 2018
  • The objective of this study was to examine the expression pattern of Kelch-like ECH-associated protein 1 (Keap1) in the maxillary $2^{nd}$ molar germs of rats. We used the maxillary $2^{nd}$ molar germs in rats' pup at postnatal day 3 (bell stage), 6 (crown formation stage) and 9 (root formation stage). The investigation on mRNA and protein levels were done using reverse transcription - polymerase chain reaction and western blot. Localization of Keap 1 in the maxillary $2^{nd}$ molar germs were revealed through immunofluorescence staining. Keap1 from the maxillary 2nd molar germs were mostly manifested on postnatal day 3 and dramatically decreased on postnatal day 6 and 9 at mRNA and protein levels, while amelogenin and ameloblastin increased during the development of maxillary 2nd molar germs. During immunofluorescence analysis, the strong immunoreactivity against Keap1 was detected in the apical side of ameloblasts at the presecretory and secretory stages. However, Keap1 expression was hardly observed in the ameloblasts at the maturation stage. These results shows that Keap1 is strongly expressed in the presecretory and secretory ameloblasts of amelogenesis, and suggest that Keap1 may be a crucial molecule for the regulatory mechanisms tasked with the formation of enamel layer.

A cone-beam computed tomography study on strategic uprighting of mandibular molars using a biocreative reverse curve system

  • Kim, Jae-Woo;Choi, Jin-Young;Kim, Min-Ji;Bin, Xu;Kim, Seong-Hun
    • The korean journal of orthodontics
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    • v.52 no.5
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    • pp.354-361
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    • 2022
  • Objective: To analyze the overall treatment effects in terms of the amount of uprighting with changes in the three-dimensional positions of the mandibular posterior teeth after applying the biocreative reverse curve (BRC) system. Methods: Thirty-four patients (mean age, 20.5 ± 8.56 years) were treated using the BRC system (mean period, 8.17 ± 2.19 months). Cone-beam computed tomography was performed before treatment and after treatment with the BRC system. The three-dimensional movement of each tooth was analyzed in the coordinate system at points on the crown and root apex. A paired t-test was used to analyze the treatment effects of the BRC system. Results: The application of the BRC system spanning from the first premolar to the second molar resulted not only in buccal and distal uprighting, but also in increased buccal and distal tipping of the teeth. The premolars and the first molar were extruded, and the second molar was intruded. Conclusions: When the BRC system is applied, simultaneous distal and buccal uprighting of the premolars and molars can be achieved bilaterally using a temporary skeletal anchorage device without unnecessary movement of the anterior teeth.

Extensive Bilateral Subcutaneous Emphysema after Dental Treatment: Two Case Reports

  • Gyu-Beom Kwon;Chul-Hwan Kim ;Hae-Seo Park
    • Journal of Korean Dental Science
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    • v.16 no.1
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    • pp.80-86
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    • 2023
  • We report two rare cases of extensive bilateral subcutaneous emphysema that occurred during ordinary dental procedures. An air-driven high-speed handpiece, routinely used in dental procedures may cause subcutaneous emphysema when high pressure air is introduced into the loose connective tissues below the dermal layer. The first case occurred with surgical extraction of the lower third molar. The air introduced into the fascial spaces near the surgical field spread to the contralateral spaces, as well as the neck and chest areas. The second case also showed extensive bilateral subcutaneous emphysema caused by the introduction of compressed air from the handpiece during crown preparation without any invasive procedure. Cases where the emphysema extends beyond the treatment site to involve the contralateral cervicofacial areas have been rarely reported. Predicting the occurrence of subcutaneous emphysema is difficult, so it is important to exercise caution during routine dental treatment. If significant bilateral cervicofacial swelling is suspected to be due to subcutaneous emphysema, prompt diagnosis with securing the patient's airway will be necessary.

Altered Expression of RANKL/OPG after Alendronate Administration in the Developing Teeth of Postnatal Rats

  • Kim, Min-Ju;Jun, Yun-Jeong;Yu, Hong-Il;Yang, So-Yeong;Oh, Won-Man;Kim, Sun-Hun;Kim, Min-Seok
    • International Journal of Oral Biology
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    • v.36 no.1
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    • pp.37-42
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    • 2011
  • The working mechanism of bisphosphonate on bone cells is unclear despite its powerful inhibitory activity on bone resorption. The differentiation and activation of osteoclasts are essential for bone resorption and are controlled by the stimulatory RANKL and inhibitory OPG molecules. Teeth exhibit a range of movement patterns during their eruption to establish their form and function, which inevitably accompanies peripheral bone resorption. Hence, the mandible, which contains the teeth during their eruption processes, is a good model for revealing the inhibitory mechanism of bisphosphonate upon bone resorption. In the present study, RANKL and OPG expression were examined immunohistochemically in the mandible of rats with developing teeth after alendronate administration (2.5 mg/kg). The preeruptive mandibular first molars at postnatal days 3 to 10 showed the developing stages from bell to crown. No morphological changes in tooth formation were observed after alendronate administration. The number of osteoclasts in the alveolar bone around the developing teeth decreased markedly at postnatal days 3, 7 and 10 compared with the control group. RANKL induced strong positive immunohistochemical reactions in the dental follicles and stromal cells around the mandibular first molar. In particular, many osteoclasts with strongly positive reactions to RANKL appeared above the developing mandibular first molars at postnatal days 3 and 10. Immunohistochemical reactions with RANKL after alendronate administration were weaker than the control groups. However, the immunohistochemical reactivity to OPG was stronger after alendronate administration, at postnatal days 3 and 10. These results suggest that alendronate may decrease bone resorption by regulating the RANKL/OPG pathway in the process of osteoclast formation, resulting in a delay in tooth eruption.

Bone-level implants placed in the anterior maxilla: an open-label, single-arm observational study

  • Gao, EnFeng;Hei, Wei-Hong;Park, Jong-Chul;Pang, KangMi;Kim, Sun Kyung;Kim, Bongju;Kim, Soung-Min;Lee, Jong-Ho
    • Journal of Periodontal and Implant Science
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    • v.47 no.5
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    • pp.312-327
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    • 2017
  • Purpose: This study assessed marginal bone remodeling and soft tissue esthetics after the loading of single bone-level implants in the anterior maxilla. Methods: An open, single-arm observational clinical trial with 3 years of follow-up was performed, including 22 implants. The patients presented with a single tooth gap in the anterior maxilla (tooth positions 14-24), with natural or restored adjacent teeth. An implant was placed at least 8 weeks post-extraction and healed submerged for 6 weeks. After the second-stage operation, a fixed provisional prosthesis was provided. The final restoration was placed 6 months after the provisional restoration. The time of the provisional crown connection was considered to be the baseline in this study. Esthetic parameters and the marginal bone level were assessed at 6, 12, 24, and 36 months. Results: All implants were well integrated in the bone. A statistically significant increase was found in the mean implant stability quotient between the time of the provisional prosthesis and the time of the final prosthesis. Most implants (95.5%) revealed marginal bone resorption (<0.5 mm), and just 1 implant (4.5%) showed a change of 2.12 mm from baseline to 36 months (mean $0.07{\pm}0.48mm$), while the crestal bone level decreased significantly, from $2.34{\pm}0.93mm$ at baseline to $1.70{\pm}1.10mm$ at 36 months. The facial gingival margin and papilla were stable and the esthetic scores indicated high patient and dentist satisfaction. Conclusions: Platform-switching bone-level implants placed in maxillary single-tooth gaps resulted in successful osseointegration with minimal marginal bone resorption. The peri-implant soft tissue was also esthetically satisfying and stable.

TREATMENT OF RADICULAR CYST USING DECOMPRESSION (감압술을 이용한 치근단 낭의 처치)

  • Kim, Nam-Hyuk;Choi, Byung-Jai;Lee, Jae-Ho;Son, Heung-Kyu;Kim, Seong-Oh;Choi, Hyung-Jun
    • Journal of the korean academy of Pediatric Dentistry
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    • v.36 no.2
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    • pp.275-280
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    • 2009
  • Radicular cyst is a true epithelium lined cyst formed when epithelium at the apex of a nonvital tooth is stimulated by inflammation. It is the most common type of cyst in the oral cavity, but its frequency is low in the primary dentition. Treatment of large-sized cyst aims at conservation of adjacent structure and allowance of proper eruption of the successive permanent teeth in the primary dentition. Considering these two aspects, marsupialization or enucleation following decompression is recommended as a treatment means for large-sized radicular cyst. In this case, 8-year old boy visited the pediatric dentistry department. Yonsei University Dental Hospital, with the chief complaint of pain on the lower right area. Clinical and radiographic examinations revealed periapical radiolucent lesion on #84, which had previous pulp treatment and restorated with the stainless steel crown. Dislocation of its successive tooth, #44, was also observed. #84 was extracted and sent for biopsy. Through histologic examination, it was diagnosed as radicular cyst. Following its extraction, removable space maintainer was delivered, which was also used as a decompressor. During periodic check-up for next 22 months, favorable healing of the lesion and eruption of the successive tooth were observed.

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A study on the micromotion between the dental implant and superstructure (임플란트와 상부구조물 사이의 micromotion에 관한 연구)

  • Kim, Ji-Hye;Song, Kwang-Yeob;Jang, Tae-Yeob;Park, Ju-Mi
    • Journal of Dental Rehabilitation and Applied Science
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    • v.19 no.1
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    • pp.17-25
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    • 2003
  • Treatment with implants of single tooth missing cases is both functional and esthetic. Although the success rate of single-tooth implant treatments is increasing, sometimes it makes some problems. Problems with single-tooth implant treatments include soft tissue complications, abutment screw fracture, and most commonly, abutment screw loosening, and these involve the instability of the dental implant-superstructure interface. This study investigated and compared dental implant screw joint micromotion of various implant system with external connection or internal connection when tested under simulated clinical loading, Six groups (N=5) were assessed: (1) Branemark AurAdapt (Nobel Biocare, Goteborg, Sweden), (2) Branemark EsthetiCone (Nobel Biocare, Goteborg, Sweden), (3) Neoplant Conical (Neobiotec, Korea), (4) Neoplant UCLA (Neobiotec, Korea), (5) Neoplant 5.5mm Solid (Neobiotec, Korea), and (6) ITI SynOcta (Institute Straumann, Waldenburg, Switzerland). Six identical frameworks were fabricated. Abutment screws were tightened to 32-35 Ncm and occlusal screw were tightened to 15-20 Ncm with an electronic torque controller. A mechanical testing machine applied a compressive cyclic load of 20kg at 10Hz to a contact point on each implant crown. Strain gauge recorded the micromotion of the screw joint interface once a second. Data were selected at 1, 500, 5,000, 10,000, 20,000, 30,000, 40,000 and 50,000 cycle and 2-way ANOVA test was performed to assess the statistical significance. The results of this study were as follows; The micromotion of the implant-superstructure in the interface increased gradually through 50,000 cycles for all implant systems. In the case of the micromotion according to cycle increase, Neoplant Conical and Neoplant UCLA system exhibited significantly increasing micromotion at the implant-superstructure interface (p<0.05), but others not significant. In the case of the micromotion of the implant-superstructure interface at 50,000 cycle, the largest micromotion were recorded in the Branemark EsthetiCone, sequently followed by Neoplant Conical, Neoplant UCLA, Branemark AurAdapt, ITI SynOcta and Neplant Solid. Internal connection system showed smaller micromotion than external connection system. Specially, Neoplant Solid with internal connection system exhibited significantly smaller micromotion than other implant systems except ITI SynOcta with same internal connection system (p<0.05). In the case of external connection, Branemark EsthetiCone and Neoplant Conical system with abutment showed significantly larger micromotion than Branemark AurAdapt without abutment (p<0.05).

MARSUPIALIZATION IN RESOLVING DENTIGEROUS CYSTS: CASE REPORT (감압조대술을 이용한 함치성낭종의 치험례)

  • Kim, Hyun-Woo;Yoon, Kyu-Ho;Park, Kwan-Soo;Jung, Jung-Kwon;Ban, Jae-Hyurk;You, Myung-Soo
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.27 no.1
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    • pp.76-80
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    • 2005
  • Dentigerous cyst is one of the most prevalent types of odontogenic cysts in the jaw. Usually dentigerous cysts begin to develope through an accumulation of fluid between remnants of the enamel organ and subjacent tooth crown which is developing or submerged. The teeth most often involved are mandibular third molars, maxillary canines, and mandibular premolars. And the cysts usually occur in the second or third decade of life. The treatment of dentigerous cysts-enucleation, marsupialization, and fenestration-is dictated by the size, environmental structures of the lesion, and desirability of conserving involved tooth. Marsupialization is a conservative technique which allows the reduction or elimination of cystic lesion by making it an accessory compartment of the oral cavity in the case where complete enucleation is not desirable. Marsupialization is thought to be the most suitable method of treatment for the conserving of the involved tooth, thus guiding eruption of it. We report the positive outcome got from marsupialization in dentigerous cysts with review of literature.

EVALUATION OF THERMAL DIFFUSION IN LOWER End PRIMARY MOLAR WITH THERMOGRAPHY AND FINITE ELEMENT ANALYSIS (Thermography와 유한요소분석법을 이용한 하악 제2유구치의 열확산도 평가)

  • Park, Hee-Seung;Kim, Yong-Kee;Kwon, Soon-Won;Kim, Jong-Soo
    • Journal of the korean academy of Pediatric Dentistry
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    • v.29 no.4
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    • pp.519-528
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    • 2002
  • It is not a rare occasion that certain dental procedures involving tooth reduction being peformed under inadequate water cooling due to a variety of reasons. This situation could possibly inflict the critical insult to the pulpal tissue of indicated tooth. The purpose of this experiment was to study the pattern of diffusion of external heat produced during routine dental procedures into the pulpal tissue. 30 stone blocks containing three lower second primary molars were used for certain restorative procedures and the temperature of the indicated tooth surface was measured by thermography(Inframetrics 600) and further used as a baseline data for the finite element analysis model fabrication designed in order to evaluate the pattern of thermal diffusion. The ranges of highest surface temperature measured from several dental procedures under water cooling and non-water cooling were $30.8^{\circ}C{\sim}43.6^{\circ}C$ and $51.2^{\circ}C{\sim}103.4^{\circ}C$ respectively. Among procedures studied, crown preparation showed the highest value and amalgam removal showed the lowest. Comparisons between data measured under water cooling and non-water cooling conditions have shown the statistically significant difference(p<0.05). All the non-cooling conditions have shown the relatively larger increment of temperature change at the pulp horn area than the cooling conditions. The results of this study strongly indicate that the water coolant is the essential element in restorative procedures for the maintenance of healthy pulp. Further related studies involving more procedures and conditions are recommended.

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