• Korean Journal of Computational Design and Engineering
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• v.5 no.4
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• pp.312-318
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• 2000

In this study, an exclusive CAD/CAM system is developed for enhancing the effectiveness and productivity of CNC universal cylindrical grinding machines on which the external/facing/internal grinding cycles and the wheel dressing cycles are integratively carried out. The CAD/CAM system can manage the various processes such as geometry design, NC code generation, NC code verification, DNC operation, and so on. Especially, the feature-based modeling concept is introduced to improve the geometry design efficiency. And the NC code verification is realized by virtual manufacturing technique based on the real-time analysis of NC codes and the boolean operation between workpiece and wheel.

• The Journal of Advanced Prosthodontics
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• v.6 no.4
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• pp.317-324
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• 2014

PURPOSE. This study was to evaluate the effect of grinding of the inner metal surface during the porcelain try-in stage on metal-porcelain bonding considering the maximum temperature and the vibration of samples. MATERIALS AND METHODS. Ninety-one square prism-shaped ($1{\times}1{\times}1.5mm$) nickel-chrome cast frameworks 0.3 mm thick were prepared. Porcelain was applied on two opposite outer axial surfaces of the frameworks. The grinding was performed from the opposite axial sides of the inner metal surfaces with a low-speed handpiece with two types of burs (diamond, tungsten-carbide) under three grinding forces (3.5 N, 7 N, 14 N) and at two durations (5 seconds, 10 seconds). The shear bond strength (SBS) test was performed with universal testing machine. Statistical analyzes were performed at 5% significance level. RESULTS. The samples subjected to grinding under 3.5 N showed higher SBS values than those exposed to grinding under 7 N and 14 N (P<.05). SBS values of none of the groups differed from those of the control group (P>.05). The types of bur (P=.965) and the duration (P=.679) did not affect the SBS values. On the other hand, type of bur, force applied, and duration of the grinding affected the maximum temperatures of the samples, whereas the maximum vibration was affected only by the type of bur (P<.05). CONCLUSION. Grinding the inner metal surface did not affect the metal-porcelain bond strength. Although the grinding affected the maximum temperature and the vibration values of the samples, these did not influence the bonding strength.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.2
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• pp.257-261
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• 2017

Drilling file is medical mini-drill which is made of Ni-Ti material and has tapered shape. It's for removing teeth nervine which helps the endodontic treatment. All files, saled at domestic market, are imported from U.S. and Europe. Also they have low manufacturing efficiency and high price because it is made by universal 5 axis CNC grinding machine. To solve these problem, 3 axis CNC table, controllable tilting angle spindle and helix angle moving table are devised. To confirm divised CNC grinding machine's manufacturing accuracy, conveying amount and finish product size measurement expreiment has been practiced. Also to automate all manufacturing processes, automatic mechanism is designed.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.3
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• pp.193-202
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• 2016

Purpose: This study was performed in order to assess the effect of the surface treatment methods and the use of bonding agent on the shear bond strength (SBS) between the aged CAD-CAM (computer aided design-computer aided manufacturing) hybrid materials and added composite resin. Materials and methods: LAVA Ultimate (LU) and VITA ENAMIC (VE) specimens were age treated by submerging in a $37^{\circ}C$ water bath filled with artificial saliva (Xerova solution) for 30 days. The surface was ground with #220 SiC paper then the specimens were divided into 9 groups according to the combination of the surface treatment (no treatment, grinding, air abrasion with aluminum oxide, HF acid) and bonding agents (no bonding, Adper Single Bond 2, Single Bond Universal). Each group had 10 specimens. Specimens were repaired (added) using composite resin (Filtek Z250), then all the specimens were stored for 7 days in room temperature distilled water. SBS was measured and the fractured surfaces were observed with a scanning electron microscope (SEM). One-way ANOVA and Scheffe test were used for statistical analysis (${\alpha}=.05$). Results: Mostly groups with bonding agent treatment showed higher SBS than groups without bonding agent. Among the groups without bonding agent the groups with aluminum oxide treatment showed higher SBS. However there was no significant difference between groups except two subgroups within LU group, which revealed a significant increase of SBS when Single Bond Universal was used on the ground LU specimen. Conclusion: The use of bonding agent when repairing an aged LAVA Ultimate restoration is recommended.

• Language and Information
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• v.12 no.1
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• pp.67-83
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• 2008

The semantics of whole involves distributivity, which may not be accounted for by the distributive operator for plurals or quantifiers. I review the pragmatic approach to whole by Moltmann (2005) and propose that the semantics of whole can be explained by the member specification function, which maps a group to its members. Although NPs with whole are morphologically singular, they become semantically plural with the application of the function. The distributive operator for plurals is introduced on a sentence with whole, which explains the distributivity of whole.

• Restorative Dentistry and Endodontics
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• v.16 no.1
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• pp.200-208
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• 1991

The purpose of this study was to observe shear bond strength of composite resin to dentin following surface treatment. Freshly extracted forty-eight sound human molars were used in this study. They were stored at $4^{\circ}C$ physiologic saline solution before experiment. The teeth was then mounted with self curing acrylic resin in brass mold. The buccal surfaces of the teeth were grinding approximately 1.5mm by means of water-irrigated grinding wheel to expose the flattened fresh dentin surfaces. The specimens were divided into 6 groups according to preparation and treatment procedures on dentin surfaces; Group 1: Untreated after preparation with No.301 diamond point Group 2: Treated with primer for 60 seconds after preparation with No.301 diamond point Group 3: Untreated after preparation with No.700 fissure carbide bur Group 4: Treated with primer for 60 seconds after preparation with No.700 fissure carbide bur Group 5: Untreated after grinding with 600 grit silicon carbide paper Group 6: Treated with primer for 60 seconds after grinding with 600 grit silicon carbide paper Light cure dental adhesive was applicated to each specimen. Silux plus(3M) was inserted then into polyethylene tube of 3mm diameter and 3mm height, and polymerized to dentin surface. All of the specimens were stored in distilled water at $35.6^{\circ}C$ for 24 hours prior to testing. The shear bond strength was measured using an Instron Universal Testing Machine. The results obtained from this study were as follows: 1. The shear bond strength to dentin was the highest in group II. 2. The shear bond strength to dentin was the lowest in group III. 3. There was no significant difference in shear bond strength to dentin according to preparation instrument. 4. The primer treatment group showed significantly greater shear bond strength than untreated group.

• 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.

• The Journal of Advanced Prosthodontics
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• v.11 no.1
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• pp.65-74
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• 2019

PURPOSE. To evaluate and compare the effect of different materials and techniques on the shear bond strength of veneering ceramic materials to zirconia. MATERIALS AND METHODS. 136 sintered zirconia cubes were prepared and randomly divided into four study groups according to corresponding methods of surface treatment and materials: GLN (grinding followed by laser scanning using Noritake Cerabien ZR), SLN (sandblasting followed by laser scanning using Noritake Cerabien ZR), GLV (grinding followed by laser scanning using VITA VM 9), and SLV (sandblasting followed by laser scanning using VITA VM 9). Spraying technique was performed to coat the core. Profilometer, SEM, XRD, EDS, universal testing machine, and stereomicroscope were used to record surface roughness Ra, surface morphology, phase transformation, elemental compositions, shear bond strength SBS values, and failure types, respectively. Specimens were investigated in unaged (not immersed in artificial saliva) and aged (stored in artificial saliva for a month) conditions to evaluate SBS values. RESULTS. Grinding and GLN as first and second surface treatments provided satisfactory Ra values in both conditions ($1.05{\pm}0.24{\mu}m$, $1.30{\pm}0.21{\mu}m$) compared to sandblasting and other groups (P<.05). The group GLN showed the highest SBS values in both conditions ($30.97{\pm}3.12MPa$, $29.09{\pm}4.17MPa$), while group SLV recorded the lowest ($23.96{\pm}3.60MPa$, $22.95{\pm}3.68Mpa$) (P<.05). Sandblasting showed phase transformation from t-m. Mixed failure type was the commonest among all groups. CONCLUSION. GLN showed to be a reliable method which provided satisfactory bond strength between the veneer ceramic and zirconia. This method might preserve the integrity of fixed dental crowns.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.356-364
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• 2007

The purpose of this study was to assess the background color-interceptive ability ana opacity of opaque shade composites (Universal composite, Filtek Z350, Charisma, Clearfil ST, Palpaque Estelite, Esthet-X, and Metafil Flo). Twenty four background specimens (diameter 5.5 mm, thickness 3.0 mm) with Root dentin Mustard (Bisco, Schaumburg, IL, USA) were made. The CIE $L^*a^*b^*$ value of background specimens was measured by a spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland). Three specimens in every group were filled on the background specimens. The surface color of samples was measured by a spectrophotometer in 3.0 mm and every thickness to 0.5 mm while grinding. The color difference in the background color along with 3.0 mm specimen gauged the masking effect in each thickness while grinding and polishing. The opacity was calculated in 1 mm thick specimens. The opacity was in the decreasing order of Clearfil ST, Metafil Flo, Filtek Z350, Palpaque Estelite, Universal composite, Charisma, and Esthet-X (p < 0.05). As the thickness get reduced, $L^*$ value showed decreasing, $a^*$ increasing tendency. The surface color difference between pair of the 3.0 mm thick specimen and after grinding in same opaque resin was above 3.3 except Clearfil ST and Metafil Flo. The color difference (${\Delta}E^*$) between pair of background specimen and opaque resin built-up specimen showed more than 10.0 regardless kinds and thickness. The variance in opacity characteristics and color of the opaque composites is dependent upon manufacturer. When using the opaque resin, the optical properties of each material must be considered as well as cavity.

• Restorative Dentistry and Endodontics
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• v.19 no.2
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• pp.447-459
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• 1994

The purpose of this study is to evaluate of shear bond strength of light-curing composite resin to light-curing glass ionomer cement. Composite resin and glass ionomer cement have been widely used as an esthetic filling materials in dental clinics. To achieve better clinical results, sandwich technic was developed with conpensating for disadvantages of these two materials. Especially, light-curing glass ionomer cement provided greately improved bonding strength of teeth or composite resin, and then excellent clinical results can be acquired. In this study, 6 commercial light-curing glass ionomer cements(3 commercial restorative materials : Fuji II LC, Variglass VLC, Vitremer, and 3 commercial lining materials : Fuji Lining LC, Baseline VLC, Vitrebond) were devided two groups. According to manufacturer's appointment, no surface treatment was referred to N groups. Supposing. of clinical practice, surface grinding with water spray at 320 grit sand paper, 40 seconds etching with 37% phosphoric acid, 20 seconds washing, 20 seconds air drying was referred to N groups. Totally 12 experimental groups were devided, and all 120 specimens from 10 specimens of each groups were made. After light-curing composite resin was bonded to light-curing glass ionomer cement, shear bond strength was tested by Instron universal testing machine between glass ionomer cement and composit resin. The data were analyzed statistically by Student's t-test and ANOVA. The obtained results were as follows; 1. In light-curing glass ionomer cement, restorative materials showed higher shear bond strength to composite resin than lining materials(p<0.05). 2. Variglass VLC of restorative material group and Baseline VLC of lining material group have highest shear bond strength to composite resin(p<0.001). 3. In light-curing glass ionomer cement, surface grinding and acid etching reduced shear bond strength to composite resin(p<0.001)}. 4. VGN group 1s highest shear bond strength to composite resin, VBE group is lowest shear bond strength to composite resin(p<0.001).