• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.173-186
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• 1993

The purpose of this study is to observe the morphological changes of prepared dentin surfaces by 5 dentin conditioning agents. Freshly extracted 48 healthy human molars were used in this study. The teeth were stored at $4^{\circ}C$ physiologic saline solution befor experiment. The teeth were cross-sectioned to expose dentin below 3.0mm at the cusp tip and above 2.0mm at the cemento-enamel junction with Crystal Cutter (MC411 D, Maruto Co., Japan). The specimens were then divided into 12 groups. The sectioned dentin surfaces in group 1, 3, 5, 7, 9, and 11 were prepared with No. 301 diamond point under air-water spray and those in group 2, 4, 6, 8, 10, and 12 were prepared with No. 700 carbide bur. The prepared dentin surfaces were conditioned with Nitric acid, Citric acid, Poly acrylic acid, EDTA, and Phosphoric acid. All the specimens were gold-coated with Eiko ion coater (Eiko-engineering Co.) and observed in Hitachi S-2300 Scanning electron microscope at 20 KV. The following results from this study were obtained; 1. The dentinal smear layers prepared with diamond point were compacted than those prepared with the carbide bur. 2. The dentinal smear layers prepared with diamond point or carbide bur were thick but after treatment of dentin conditioning agents smear layers were removed almost. 3. Irrespective of the uses of the diamond point or the carbide bur the morphological changes of dentin surfaces treated with the same conditioning agents were similar. 4. Treatment of nitric acid and EDTA was a little effect in removing dentinal smear layer. 5. Treatment of citric acid and phosphoric acid removed the smear layer very effectively and showed dissolution of peritubular dentin and opening of dentinal tubules.

• The korean journal of orthodontics
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• v.49 no.6
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• pp.404-412
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• 2019

Objective: To assess shear bond strength and failure mode (Adhesive Remnant Index, ARI) of orthodontic brackets bonded to polymethylmethacrylate (PMMA) blocks for computer-aided design/manufacture (CAD/CAM) fabrication of temporary restorations, following substrate chemical or mechanical treatment. Methods: Two types of PMMA blocks were tested: $CAD-Temp^{(R)}$ (VITA) and $Telio^{(R)}$ CAD (Ivoclar-Vivadent). The substrate was roughened with 320-grit sandpaper, simulating a fine-grit diamond bur. Two universal adhesives, Scotchbond Universal Adhesive (SU) and Assure Plus (AP), and a conventional adhesive, Transbond XT Primer (XTP; control), were used in combination with Transbond XT Paste to bond the brackets. Six experimental groups were formed: (1) $CAD-Temp^{(R)}/SU$; (2) $CAD-Temp^{(R)}/AP$; (3) $CAD-Temp^{(R)}/XTP$; (4) $Telio^{(R)}$ CAD/SU; (5) $Telio^{(R)}$ CAD/AP; (6) $Telio^{(R)}$ CAD/XTP. Shear bond strength and ARI were assessed. On 1 extra block for each PMMA-based material surfaces were roughened with 180-grit sandpaper, simulating a normal/medium-grit ($100{\mu}m$) diamond bur, and brackets were bonded. Shear bond strengths and ARI scores were compared with those of groups 3, 6. Results: On $CAD-Temp^{(R)}$ significantly higher bracket bond strengths than on $Telio^{(R)}$ CAD were recorded. With XTP significantly lower levels of adhesion were reached than using SU or AP. Roughening with a coarser bur resulted in a significant increase in adhesion. Conclusions: Bracket bonding to CAD/CAM PMMA can be promoted by grinding the substrate with a normal/medium-grit bur or by coating the intact surface with universal adhesives. With appropriate pretreatments, bracket adhesion to CAD/CAM PMMA temporary restorations can be enhanced to clinically satisfactory levels.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.389-396
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• 2002

The purpose of this study was to compare the microtensile bonding strength of chemomechanically excavated dentin($Carisolv^{TM}$) to conventional caries removal(bur). The following adhesive systems were used; AB: All-Bond 2(3M, USA), PB: Prime & Bond 2.1(Dentsply, DE), AQ: AQ Bond(sun medical, Japan). 42 human molars with occlusal caries were assigned to 6 groups. Sequential caries removal was controlled with laser fluorescence. Each group was devided as follows; group A, B, C were $Carisolv^{TM}$ applied, group D,E,F were bur used. In group A and D, AB was used as a dentin adhesive. group B,E and group C,F was AQ and AQ was used each. The cavity was filled with composite resin(Z-100). The specimens were sectioned vertically into multiple serial 0.7 mm thick slabs. And then those slabs were sectioned into rectangular parts under 0.7 mm width. Finally 0.7-1.0 mm a right hexahedron shape stick become. Microtensile bonding test was carried out with testing apparatus at cross-head speed of $0.5\;mm/min^{-1}$ and fractured surfaces were observed with scanning electron microscope(JSM-6400, Jeol, Japan). The obtained results were summarized as follows ; 1. In the group of caries removal with $Carisolv^{TM}$, micro-tensile bonding strength decreased to $75.8{\sim}80$ percent of bur used group. 2. In the group of caries removal with $Carisolv^{TM}$, decreased degree of micro-tensile bonding strength is not so different in 3 kinds of dentin adhesives(p<0.05). 3. In the group of caries removal with $Carisolv^{TM}$, microtensile bonding strength of AB, PB, AQ was 32.6MPa(2.4), 30.1Mpa (1.8), 21.2Mpa(1.9). 4. In the group of caries removal with Bur and $Carisolv^{TM}$, microtensile bonding strength of AQ was significantly lower than that of AB and PB(p<0.01).

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.205-215
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• 1997

In periodontal regeneration treatment, access to the frucation area is very difficult. Thus complete removal of plaque, calculus and endotoxin is somewhat impossible. In this study, teeth that were extracted due to periodontal disease were used. The furcation area was treated with periodontal curette, ultrasonic scaler, roto bur and they observed using SEM. The result was follows 1. The group treatment with curette showed remaining plaque, the cementum existed in most of the surface and partial dentinal tubule orifice could be seen. 2. The group treatment with ultrasonic scaler showed less removalof plaque compared to curette and irregular surface could be seen. 3. The group treatment with roto bur showed cleaner surface and many dentinal tubule orifice could be seen compared to the curette and ultrasonic scaler groups. Thus when suing treatments such as bone grafting or guided tissue regeneration, it is considered that the furcation area should be treatment with Roto bur.

• The korean journal of orthodontics
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• v.15 no.2
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• pp.271-277
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• 1985

With modification of the acid etch technique and improvements of the physical and mechanical properties of the acrylic resin, the removal of directly bonded attachments and the finishing of the underlying enamel have become an acute clinical problem. This study was to evaluation the efficacy of recently introduced instrumentation and techniques to remove bonded brackets and residual resin, and restore the affected enamel surface to an acceptable clinical condition. Fortyeight premolar which were scheduled for extraction for orthodontic purposes were bonded with brackets using super-C ortho. Four additional premolars with untreated surfaces were used as controls. After one weak the brackets were removed and the residual resin removed by hand scaler, green stone, green rubber wheel, sandpaper disc, tungsten carbide bur, Sof-lex disc. Half the experimental teeth were given a final pumicing and then all were extracted and stored in 50 percent ethanol. The scanning electron microscopy was used to evaluated the enamel surface. Following results were obtained; 1. A satisfactory result was obtained by means of the Sof-lex disc. 2. The order of the scratch formation was the procedure using hand scaler, green atone, tungsten carbide bur, sandpaper disc, green rubber wheel, and Sof-lex disc. 3. The procedures using green stone and tungsten carbide bur showed many groove formations and the other procedures showed none. 4. final pumicing serves effectively to remove residual adhesive and restore the enamel surface.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.12
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• pp.66-72
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• 1997

This paper aims at reviewing the possibility application over normal or abnormal, detection used by AE and the wear characteristics of grinding process. In this study, when diamond bur in dentistry with chosen grinding conditions were tuned at grinding. The variation of grinding resistance and AE signal is detected by the use of AE measuring system. The tests are carried out in accordance with diamond burs and workpiece: arcyl and bovine. According to the experiment results, the following can be expected: AE has the possibility to detect the state normality and abnormality. Hpwever, the grinding resistance measuring can find it difficult to detect it. It can be accurately excepted from AE occurrence pattern in contact start point of diamond bur and bovine, grinding condition and derailment point. It is known that AErms is well compatible with grinding resistance. According to the increase of the material removal rate, the specific energy of the diamond bur is inclined to dectease and the grinding resistance has a tendency to increase.

• Journal of Life Science
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• v.24 no.11
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• pp.1193-1199
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• 2014

The aim of this study was to show the antioxidant properties of chestnut (Castanea crenata) bur extracts fermented by Lactobacillus casei. The chestnut has been used as a cosmetic material in Korea for many years. This study showed that reactive oxygen species (ROS) were inhibited by the fermentation materials of chestnut bur extracts. The antioxidant activities were analyzed and expressed as EDA, ABTS, reducing power, SOD-like activity, hydrogen peroxide scavenging activity, superoxide anion radical scavenging activity, and nitric oxide scavenging ability. The antioxidant activities of fermentation materials from L. casei of chestnut bur extracts were higher than those of butylated hydroxyanisole (BHA), epigallocatechin gallate (EGCG), and ascorbic acid (AA). Therefore, we expect that fermentation materials from L. casei of chestnut bur extracts are valuable resources as natural antioxidants and functional cosmetics ingredients.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.20 no.2
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• pp.265-276
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• 1990

The purpose of this experiment was to evaluate radiographic interpretation, of various sized 60 periapical and 60 cancellous lesions in 10 mandibular sections of 5 dogs according to kVp (65, 70, 75, 80 and 85 kVp). The results were as follows; The change of kilovoltage within 65kVp-85kVp range did not have influence on the radiographic interpretation of the same-sized bony defects at the constant radiographic density (p> 0.05). When the bony defects were less than the size of No.2 round bur, radiographic interpretation of bony defects prepared with No.2 round bur was easier than those prepared with No. 1 round bur at 80-85kVp in periapical region (p<0.05). However, in cancellous bone, this radiographic interpretation was easier at 65-75kVp (p<0.05). There were significant differences in the radiographic interpretation between the defects confined only to the cancellous, bone and the defects involved in the compact bone (p<0.05). However there were no significant differences between the defects confined only to the cancellous bone and the defects involved in junctional area of cancellous and compact bone (p>0.05). From the results of densitometric analysis, there was a difference in densitometric measurements at the same radiographic interpretation scores, and aluminum equivalent differences of 0.15-1.66㎜ thickness were needed for radiographic interpretation.

• Korean Journal of Weed Science
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• v.32 no.3
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• pp.195-203
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• 2012

The essential oil was extracted by steam distillation from the aerial part of erect bur-marigold (Bidens tripartita L.), one of the noxious weed in paddy field. The composition of the essential oil was analyzed by gas chromatography-mass spectrometry. The fragrance of the essential oil was green, herbal, oily, spicy. There were 42 constituents in the essential oil：17 hydrocarbons, 6 alcohols, 6 acetates, 5 N-containing compounds, 3 ethers, 3 ketones, 1 lactone and 1 S-containing compound. Major constituents were ${\alpha}$-phellandrene (22.50%), ${\alpha}$-pinene (22.21%), 2,4-dimethyl (2,5-dimethylphenyl) methyl ester benzoic acid (15.11%), limonene (10.66%), ${\beta}$-pinene (35.43%), and ${\beta}$-cubebene (5.27%). The $IC_{50}$ value in MTT assay using HaCaT keratinocyte cell line was 0.018%. However, attachment of patch with 0.1% of the erect bur-marigold essential oil for 24 hr did not show any skin toxicity. Overall results of this study suggest that the essential oil of erect bur-marigold could be used as a source for the development of perfumery industrial products.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.546-559
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• 1997

The purposes of this study were to evaluate the efficiency of cavity preparation and to determine the incidence of tooth crack when root-end retrograde cavity preparation was done with ultrasonics. 91 distobuccal root-ends of extracted human maxillary first molars were cut by 3 mm perpendicularly to the long axis of tooth using a slow speed diamond saw, retrocavities were prepared using a slow-speed no. 2 round bur as controls, and stainless steel ultrasonic tips of power settings of 1 through 10 as experimentals. Time consumed and the number of strokes used for the cavity preparation were measured and evaluated, and the incidence of tooth cracks was observed under a stereomicroscope. The results were as follows : For the retrograde cavity preparation, time and number of strokes used were decreased as the ultrasonic power setting increased (p<0.001). High power setting of ultrasonics induced significantly more tooth cracks than did the slow-speed bur or low- and medium power setting of ultrasonics (p<0.05). Teeth with previous crack induced significantly more tooth cracks than those without previous one when high power setting of ultrasonics were used for the retrograde cavity preparation (p<0.001). Teeth with initial apical canal size of no. 10 induced significantly more crack than did those with size of no. 15 when low power setting of ultrasonics were used for the retrograde cavity preparation (p<0.05).