• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.405-413
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• 2021

The purpose of this in vivo study was to assess the clinical screening performance of a quantitative light-induced fluorescence (QLF) device in detecting proximal caries in primary molars. Fluorescence loss, red autofluorescence and a simplified QLF score for proximal caries (QS-proximal) were evaluated for their validity in detecting proximal caries in primary molars compared to bitewing radiography. Three hundred and forty-four primary molar surfaces were included in the study. Carious lesions were scored according to lesion severity assessed by visual-tactile and radiographic examinations. The QLF images were analyzed for two quantitative parameters, fluorescence loss and red autofluorescence, as well as for QS-proximal. For both quantitative parameters and QS-proximal, the sensitivity, specificity and area under receiver operating curve (AUROC) were calculated as a function of the radiographic scoring index at enamel and dentin caries levels. Both quantitative parameters showed fair AUROC values for detecting dentine level caries (△F = 0.794, △R = 0.750). QS-proximal showed higher AUROC values (0.757 - 0.769) than that of visual-tactile scores (0.653) in detecting dentine level caries. The QLF device showed fair screening performance in detecting proximal caries in primary molars compared to bitewing radiography.

• Restorative Dentistry and Endodontics
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• v.9 no.1
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• pp.115-119
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• 1983

The purpose of this study was to compare the solubility of enamel and dentin to an etchant after fluoride application. Specimens were collected from extracted anterior and bicuspid and each tooth was cut into several pieces. These specimen were allocated in 7 group; 1%, 2%, 3% NaF, 1%, 8%, 20% $SnF_2$, and control group. Five specimens in each group was exposed to pre-determined fluoride solution for 3 minutes, and washed with running water. These specimens were etched by Hipol (commercial label) etchant for 30 seconds. Following are the findings obtained through S.E.M. 1. All specimens with acid etching revealed preferential removal of prism periphery leaving prism core. 2. Specimens treated with 1%, 2% NaF solution showed that the shape of prism tip was thin and sharp like a needle. The case of 3% NaF showed rather round shape at prism end. 3.1% of $SnF_2$ case showed similar findings with the control group but 8% and 20% $SnF_2$ case revealed needle shape at the prism and was less clear than NaF case. Preferential removal of prism periphery was partialy observed and un decalcified area is fused to prism forming reidge. 4. Dentine treated by fluoride compound in low concentration showed the orifice of dentinal tubule was clearly enlarged whereas in high concentration the orifice was not widened.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.1
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• pp.68-78
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• 2002

The post core system has been used for reconstructon of severely damaged crown by caries or trauma. But problems such as crown exfoliation, post core fracture and root fracture have been reported. Ideal mechanical properies of the post require high fracture strength, high elastic limit and high resistance against fatigue and corrosion Modulus of elasticity of the post should be similar with that of dentine. Low hardness is also required for the convenience of post removal in failure. Furthermore, the post itself must be translucent for the esthetical purpose. Several types of the post have been developed to satisfy the criteria above mentioned. The purpose of this study was to find out the mechanical properties of quartz fiber post by comparing with those of gold post and zirconia post. The results of this study were as follows : 1. Maximal fracture strength and stiffness of quartz fiber post were similar with those of gold post and zirconia post. 2. Young's modulus and hardness of quartz fiber post were lower than those of gold post and zirconia post. Mechanical property of quartz fiber post against post fracture was similar with that of gold post and zirconia post. Mechanical property of quartz fiber post against root fracture was higher than that of gold post and zirconia post. Quartz fiber post could be removed easily due to low hardness.

• Restorative Dentistry and Endodontics
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• v.8 no.1
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• pp.133-137
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• 1982

Radiography is one of the important tool adopted in daily dental practice and medical diagnosis. To visualize soft tissuechange various contrast media has Been introduced. Any cavity or space can be easily determined by increasing the X-ray absorption of the cavity using the radiopaque contrast media which widely employed in medical radiography to show much of the digestive, cardiovascular, pulmonary, and renal system. The essential part of any radiopaque medium is a heavy element that can absoarb most of the X-ray beam. The element must be noninjurious and easily eliminated. Both aqueous and oil suspensions of iodine containing compounds' are available to the dental profession, for example Lipiodol and Dionosil. The study was designed to determine toxic effect of Lipiodol to the vital pulp and to confirm visualization ioprovement in pulp canal. 1. Thin mixture of Calcium hydroxide and Lipiodol was applied to 19 deep vital cavities for 24 hours. Only one case complained slight pain for short time. 2. Cotton pellet over-saturated in Lipiodol was inserted in coronal chamber of which 6 were non vital and 5 were vital. The transference of Lipiodol was not noticed in every case after 24 hours. 5 cases with vital pulp tissue in the canals showed no clinical symptome. 3. Extracted 20 teeth were routinely prepared for endodontic treatment and applied Lipiodol in conjunction with cotton fiber as deep as midportion of the roots. After 24, hours the medicament reached to nearly the end of apex, but there were no evidence of penetration in dentine layer and migrate into ramified canal.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.2
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• pp.179-182
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• 2006

The term odontoma, first introduced by Broca, was originally applied to all odontogenic tumors. Related to the clinical and histological differences, 2 groups of odontoma were defined: compound odontoma and complex odontoma. Complex odontoma is more common in the mandible than in the maxilla, usually occuring in the mandibular premolar-molar area. And this consists of small mass of irregularly arranged enamel, dentine, cementum, and connective tissue, but tooth-like structures are not found. In our case, 34 year old man was diagnosed as the complex odontoma of maxillary sinus by the physical exam, Panex, and C.T scan. We sectioned and removed it, and then confirmed the diagnosis histopathologically. Its uncommon location and size made us report that case and review the literature concerned.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.51-60
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• 2006

Gingival recession is clinically manifested by an apical displacement of the gingival tissue and dentin hypersensitivity is often used to describe a painful condition in which exposed dentin is unduly sensitive to intraoral stimuli. The objects of this study were primarily to investigate the prevalence and distribution of gingival recession and hypersensitivity and secondarily to determine whether a relationship exists between gingival recession and hypersensitivity. The study population was 195 patients (102 males, 93 females) who were attended the department of periodontology, Pusan National University Hospital. 189 patients exhibited gingival recession at least more than 1 tooth, the prevalence was 96.9%. The maxillary and mandibular first premolar and mandibular incisors had the highest prevalence. The majority of patients (139 patients, 71.3%) were diagnosed as having dentin hypersensitivity. Dentin hypersensitivity was determined to 3 seconds application of cold air to the exposed root surface after isolating the test tooth and was commonest in maxillary and mandibular first premolars and mandibular incisors. Relationship between recession and hypersensitivity was analyzed using chi-square test (p=0.05), significant relation (p=0.000) was existed. Gingival recession was more severe, the prevalence of hypersensitivity was higher.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.12
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• pp.990-995
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• 2012

A piezoelectric ultrasonic bone surgical instrument, usually used to remove the tartar out of teeth or to cut the dentine of the tooth, is a recently popular instrument for dental treatment due to its several merits such as small size, low-electric power and precision control of surgical operation. It has typically two parts of a tip and vibration system which is also composed of head, piezoelectric elements and tail-mass. In order to improve the performance of the instrument, it is important to standardize the size of the vibration system without tip for high performance. In this study, a Finite Element Analysis (FEA) was utilized to optimize the structure of ultrasonic instrument in vibration system. Consequently, this study revealed that influence of several tips on property were minimized and it showed good property at the frequency range of 22~32 kHz.

• Restorative Dentistry and Endodontics
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• v.44 no.4
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• pp.37.1-37.10
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• 2019

Objectives: This study evaluated the bond strength of various fiberglass post cementation techniques using different resin-based composites. Materials and Methods: The roots from a total of 100 bovine incisors were randomly assigned to 5 treatment groups: G1, post + Scotchbond Multi-Purpose (SBMP) + RelyX ARC luting agent; G2, relined post (Filtek Z250) + SBMP + RelyX ARC; G3, individualized post (Filtek Z250) + SBMP; G4, individualized post (Filtek Bulk-Fill) + SBMP; G5, individualized post (Filtek Bulk-Fill Flow) + SBMP. The samples were subjected to the push-out (n = 10) and pull-out (n = 10) bond strength tests. Data from the push-out bond strength test were analyzed using 2-way analysis of variance (ANOVA) with the Bonferroni post hoc test, and data from the pull-out bond strength test were analyzed using 1-way ANOVA. Results: The data for push-out bond strength presented higher values for G2 and G5, mainly in the cervical and middle thirds, and the data from the apical third showed a lower mean push-out bond strength in all groups. No significant difference was noted for pull-out bond strength among all groups. The most frequent failure modes observed were adhesive failure between dentine and resin and mixed failure. Conclusions: Fiberglass post cementation using restorative and flowable bulk-fill composites with the individualization technique may be a promising alternative to existing methods of post cementation.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.157-161
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• 1999

Odontomas, hamartomas of odontogenic origin, are composed of all the structures that make up teeth. The WHO distinguishes odontoma into two types. The complex odontoma is defined as "a malformation in which all the dental tissues are represented, individual tissues being mainly well-formed but occurring in a more or less disorderly pattern." The compound odontoma is defined as "a malformation in which all the dental tissues are represented in a more orderly pattern than in the complex odontoma, so that the lesion consists of many toothlike structures. Most of these structures do not resemble morphologically the teeth of normal dentition, but in each one enamel, dentine, cementum, and pulp are arranged as in the normal tooth." Almost all odontomas are located intraosseously, but they have occasionally been reported in extrabony location. Peripheral or soft tissue odontomas, those arising outside of the alveolar bone, are very rare. Peripheral or soft tissue odontoma are defined as tumors that demonstrate the histologic characteristics of their intraosseous counterparts but occur solely in the soft tissue covering the tooth-bearing portion of the mandible and maxilla. When they mature, they appear as a radiopaque mass without the peripheral halo. The final diagnosis should be confirmed by biopsy. The origin of peripheral odontoma is probably related to remnants of the dental lamina in the gingiva. The treatment of choice is complete surgical excision, similarly to intraosseous odontoma and it does not tend to recur. This report presents a case of 5-year-old boy with swelling on labial gingiva of primary central incisor. And it was diagnosed as peripheral odontoma by excisional biopsy.

• The Journal of Advanced Prosthodontics
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• v.8 no.3
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• pp.201-206
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• 2016

PURPOSE. The aim of this study was to compare the radiopacity of 6 modern resin cements with that of human enamel and dentine using the Digora digital radiography system, to verify whether they meet the requirements of ANSI/ADA specification no. 27/1993 and the ISO 4049/2000 standard and assess whether their radiopacity is influenced by the thickness of the cement employed. MATERIALS AND METHODS. Three 3-thickness samples (0.5, 1 and 1.5 mm) were fabricated for each material. The individual cement samples were radiographed on the CCD sensor next to the aluminium wedge and the tooth samples. Five radiographs were made of each sample and therefore five readings of radiographic density were taken for each thickness of the materials. The radiopacity was measured in pixels using Digora 2.6 software. The calibration curve obtained from the mean values of each step of the wedge made it possible to obtain the equivalent in mm of aluminium for each mm of the luting material. RESULTS. With the exception of Variolink Veneer Medium Value 0, all the cements studied were more radiopaque than enamel and dentin (P<.05) and complied with the ISO and ANSI/ADA requirements (P<.001). The radiopacity of all the cements examined depended on their thickness: the thicker the material, the greater its radiopacity. CONCLUSION. All materials except Variolink Veneer Medium Value 0 yielded radiopacity values that complied with the recommendations of the ISO and ANSI/ADA. Variolink Veneer Medium Value 0 showed less radiopacity than enamel and dentin.