• Restorative Dentistry and Endodontics
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• v.17 no.1
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• pp.191-205
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• 1992

The purpose of this study was to evaluate the microleakage of class II composite resin inlays and compare them with the conventional light-cured resin filling restorations. Class II cavities were prepared in 60 extracted human molars with which cervical margins were located below 1.0mm at the cemento-enamel junction using No. 701 tapered fissure carbide bur. All of the prepared cavities were restored as follows and divided into 6 groups. Group I and 2 were restored using direct filling technique and group 3,4,5 and 6 were restored using direct inlay technique that was cemented with dual-cured resin cements. group I: Cavities were restored with light-curing composite resin, Brilliant Lux. group 2. Cavities were restored with light-curing composite resin, Clearfil PhotoPosterior. group 3: Cavities were restored with Clearfil CR Inlay and heat treated at $125^{\circ}C$ for 7 minutes. group 4: Cavities were restored with same material as group 3 and heat treated at $100^{\circ}C$ for 15 minutes. group 5: Cavities were restored with Brilliant (Indirect esthetic system) and heat treated at $125^{\circ}C$ for 7 minutes. group 6: Cavities were restored with same material as group 5 and heat treated at $100^{\circ}C$ for 15 minutes. All specimens were polished with same method and thermocycled between $6^{\circ}C$ and $60^{\circ}C$, then immersed in a bath of 2.0% aqueous solution of basic fuchsin dye for 24 hours. Dyed specimens were sectioned longitudinally and dye penetration degree was read on a scale of 0 to 4 by Tani and Buonocore's method 45). The results were as follows: 1. Microleakage was observed rather at the cervical margins than at the occlusal margins in all groups. 2. Composite resin inlay groups showed significantly less leakage than direct filling groups at the cervical margins (p < 0.001). 3. In composite resin inlay groups, there was no significant difference in microleakage between specimens by heat treating temperature and time (p > 0.05). 4. There was no significant difference in leakage between each groups at the occlusal margins (p > 0.05).

• Restorative Dentistry and Endodontics
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• v.19 no.1
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• pp.231-254
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• 1994

Fracture of cusp, on posterior teeth, especially those carious or restored, is major cause of tooth loss. Inappropriate treatments, such as unnecessarily wide cavity preparations, increase the potential of further trauma and possible fracture of the remaining tooth structures. Fracture potential may be directly related to the stresses exerted upon the tooth during masticatory function. The purpose of this study is to evaluate the fracture resistance of tooth, restored with composite resin inlay. In this study, MOD inlay cavity prepared on maxillary first premolar and restored with composite resin inlay. Three dimensional finite element models with eight nodes isoparametric solid element, developed by serial grinding-photographing technique. These models have various occlusal isthmus and depth of cavity, 1/2, 1/3 and 1/4 of isthmus width and 0.7, 0.85 and 1.0 of depth of cavity. The magnitude of load was 474 N and 172 N as presented to maximal biting force and normal chewing force. These loads applied onto ridges of buccal and lingual cusp. These models analyzed with three dimensional finite element method. The results of this study were as follows : 1. There is no difference of displacement between width of occlusal isthmus and depth of cavity. 2. The stress concentrated at bucco-mesial comer, bucco-disal comer, pulpal line angle and the interface area between internal slopes of cusp and resin inlay. 3. The vector of stress direct to buccal and lingual side from center of cavity, to tooth surface going on to enamel. The magnitude of vector increase from occlusal surface to cervix. 4. The crack of tooth start interface area, between internal slop of buccal cusp and resin inlay. It progresses through buccopulpal line angle to cervix at buccomesial and buccodistal comer. 5. The influence with depth of cavity to fracture of tooth was more than width of isthmus. 6. It would be favorable to make the isthmus width narrower than a third of the intercuspal distance and depth of cavity is below 1 : 0.7.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.103-113
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• 1993

The purpose of this study was to evaluate the tensile bond strength of composite resin inlays according to the their internal surface treatment and types of luting cement and compared them with the conventional direct resin filling thchnique. Class II cavities were prepared in 50 extracted human molar teeth, and then equally divided into five groups. Group 1 : Cavities of control group were directly filled with P-50. Group 2 : Cavities of resin inlay group were luted with resin cement. Group 3 : Cavities of resin inlay group were luted with luting G-I cement. Group 4 : Cavities of resin inlay group were luted with resin cement after sandblasting. Group 5 : Cavities of resin inlay group were luted with luting G-I cement after sandblasting. All specimens were polished with same method and stored in normal saline for 24 hours before testing. An Universal Testing machine(Model No. AGS-100A, Shimadzu, Japan) was used to apply tensile loads in the vertical direction, and the force required for separation was recorded with a cross-head speed of 5mm/min and 100kg in full scale. The results were as follows : 1. The mean tensile bond strength was lowest in group luted with luting G-I cement, with measurements of $14.45{\pm}0.78(kg/cm^2)$ and highest in group luted with resin cement after sandblasting, with measurements of $49.6{\pm}2.74(kg/cm^2)$. 2. The tensile bond strength was greater in resin inlay groups luted with resin cement than in control group and resin inlay groups luted with luting G-I cement(P<0.05). 3. The tensile bond strength was lower in resin inlay groups luted with luting G-I cement than in control group(P<0.05). 4. The tensile bond strength was greater in resin inlay groups luted with resin cement or luting G-I cement after sandblasting than without that(P<0.05).

• Restorative Dentistry and Endodontics
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• v.25 no.1
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• pp.17-40
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• 2000

Resin cements are used for cementing indirect esthetic restorations such as resin or porcelain inlays. Because of its limitations in curing of purely light cured resin cements due to attenuation of the curing light by intervening materials, dual cured resin cements are recommended for cementing restorations. The physical properties of resin cements are greatly influenced by the extent to which a resin cures and the degree of cure is an important factor in the success of the inlay. The purpose of this study was to evaluate the influence of porcelain thickness and exposure time on the polymerization of resin cements by measuring the microhardness and the degree of conversion, to investigate the nature of the correlation between two methods mentioned above, and to determine the exposure time needed to harden resin cements through various thickness of porcelain. The degree of resin cure was evaluated by the measurements of microhardness [Vickers Hardness Number(VHN)] and degree of conversion(DC), as determined by Fourier Transform Infrared Spectroscopy(FTIR) on one light cured composite resin [Z-100(Z)] and three dual cured resin cements [Duo cement(D), 3M Resin cement(R), and Dual cement(DA)] which were cured under porcelain discs thickness of 0mm, 1mm, 2mm, 3mm with light exposure time of 40sec, 80sec, 120sec, and regression analysis was performed to determine the correlation between VHN and DC. In addition, to determine the exposure time needed to harden resin cements under various thickness of porcelain discs, the changes of the intensity of light attenuated by 1mm, 2mm, and 3mm thickness of porcelain discs were measured using the curing radiometer. The results were obtained as follows ; 1. The values of microhardness and the degree of conversion of resin cements without intervening porcelain discs were 31~109VHN and 51~63%, respectively. In the microhardness Z was the highest, followed by R, D, DA. In the degree of conversion, D and DA was significantly greater than Z and R(p<0.05). 2. The microhardness and the degree of conversion of the resin cements decreased with increasing thickness of porcelain discs, and increased with increasing exposure time, D and R showed great variation with inlay thickness and exposure time, whereas, DA showed a little variation. 3. The intensity of light through 1mm, 2mm, and 3mm porcelain inlays decreased by 0.43, 0.25, and 0.14 times compared to direct illumination, and the respective needed exposure times are 53 sec, 70 sec, and 93 sec. In D and R, 40 sec of light irradiation through 2mm porcelain disc and 80 sec of light irradiation through 3mm porcelain disc were not enough to complete curing. 4. The microhardness and the degree of conversion of the resin cements showed a positive correlationship(R=0.791~0.965) in the order of R, D, Z, DA. As the thickness of porcelain discs increased, the decreasing pattern of microhardness was different from that of the degree of conversion, however.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.4
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• pp.376-382
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• 2011

In clinical dentistry, it is not difficult to meet the permanent first molars with severe coronal caries lesions in children or adolescents. The circumstances surrounding the first molars of children and adolescents are so immature and imperfect compared with those of adults. So we thought it significant to understand the status of these teeth at the moment of endodontic treatment and immediate cause of it. 106 patients with 135 permanent molars necessitating endodontic treatment in childhood and adolescence were included in this study, and the dental records and radiographs were examined. 1. The mean age was 11.9 year (male 11.5, female 12.5) and the result shows significant difference between gender(p<0.05). The mandibular teeth took more than half percentage than maxillary teeth. 2. Of 135 teeth, 45.2 percent of teeth had history of dental treatment previously and 16.3 percent of teeth showed necessity of re-endodontic treatment. 3. Of 73 teeth, 22 teeth had mesial-wall cavity causing endodontic treatment, 39 had occlusal cavity, and 12 had distal cavity.

• Restorative Dentistry and Endodontics
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• v.21 no.2
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• pp.619-627
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• 1996

There are increasing use of composite resin in the posterior teeth and the new indirect inlay technique was introduced for compensating much troubles faced in direct technique. Many researchers insisted that overall properties of restorative materials were enhanced by an additional curing but this technique still has a problems about using cement material. Resin inlay obtains retention force from friction and another adhesion to tooth structure. A shape of cavity preparation was noted but studies about cement thickness and bond strength with cavity divergency are rare. The purpose of this study is to assess the effect of cavity divergency on cement thickness and bond strength of resin inlay. Cavities, which divergency was $6^{\circ}$, $16^{\circ}$, and $26^{\circ}$ in each group, were prepared and their divergency was verified by Adobe Photoshop program through the image capture with stereo microscope and FlexCam. Inlays were fixed into the cavities with a resin cement, Superbond and were handled under chemical (in 75% ethanol for 24 hrs.) and thermal stress (500 cycles from $5^{\circ}$ to $55^{\circ}C$). MXT 70 (x400) was used for measuring the cement thickness and bond strength was evaluated with a universal testing machine. Following results were obtained : 1. The cement thickness in Mean (S.D.) were; 35.58 (10.31)${\mu}m$ in $6^{\circ}$ group, 35.97 (10.49)${\mu}m$ in $16^{\circ}$ group, and 41.43 (9.33)${\mu}m$ in $26^{\circ}$ group. But there was no significant difference between groups. 2. The bond strength in Mean (S.D.) were ; 33.18 (5.53)kg in $6^{\circ}$ group, 23.47 (13.40)kg in $16^{\circ}$ group, and 19.75 (10.48)kg in $26^{\circ}$ group. $6^{\circ}$ group showed significantly higher value compared to $16^{\circ}$ and $26^{\circ}$ groups (p<0.05). Although the results of this study indicate $6^{\circ}$ divergency will be good for resin inlay, cavity preparation with this type will have lots of difficulties in manufacturing, try-in, and cementation procedures, such as deformation. So it is concluded that $16^{\circ}$ divergent cavity preparation is recommended in resin inlay technique.

• Journal of Technologic Dentistry
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• v.41 no.1
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• pp.21-27
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• 2019

Purpose: To evaluate 2D and 3D of occulsal, mesial-occlusal and mesial-occlusal-distal cavity of composite resin inlay. Methods: Abutment tooth 16, 36 of FDI system was selected for the study. Inlay prostheses classified as occlusal cavity (OC group), mesial-occlusal (MOC) and mesial-occlusal-distal cavity (MODC) were prepared using composite resin. Composite resin was injected with composite resin in prepared tooth cavity and then photopolymerized with UV light. Additional thermal polymerization was performed. Marginal gap of composite resin inlays were measured by digital microscope(x160) with silicone replica technique. The data was analyzed from statistical software for Kruskal-Wallis test (${\alpha}=0.05$). 3-dimensional analysis was analyzed through superimposition method. Results: The smallest 2D marginal fit measure of the three groups was $47.0{\pm}21.6{\mu}m$ in the MOC group. The largest 2D marginal was $69.1{\pm}33.8{\mu}m$ in the MODC group. In the trueness of the three groups, the most accurate figure was $14.4{\pm}2.3{\mu}m$ for the MODC group. In Precision, the most accurate figure was $14.5{\pm}4.3{\mu}m$ for the MODC group. Conclusion : In this study, 2D marginal fit of OC, MOC, and MODC cavities fabricated with composite resin was applicable to all clinical applications. In the 3D inner surface accuracy evaluation, the MODC group showed the accuracy results.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.254-266
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• 1997

This study was to know the usefulness of argon laser for composite resin, to prove the polymerized effect of heat treatment of composite resin inlay and to get the curing method for optimal physical properties of composite resin inlay. In this study we used four light curing units and one heat curing unit: Visilux $II^{TM}$, a visible light gun: $SPECTRUM^{TM}$, an argon laser: Unilux AC$^{(R)}$ and Astorn XL$^{(R)}$, visible light curing unit: CRC-$100^{TM}$ for heat treatment. Compared to a control group, we divided the experemental groups into five as follows: Control group: Light curing(Visilux $II^{TM}$) Experimental group 1 : Light curing(Visilux $II^{TM}$) + Light curing(Unilux AC$^{(R)}$) Experimental group 2: Light curing(Visilux $II^{TM}$) + Light curing(Astron XL$^{(R)}$) + Heat treatment(CRC-$100^{TM}$) Experimental group 3 : Laser curing($SPECTRUM^{TM}$) Experimental group 4 : Laser curing($SPECTRUM^{TM}$) + Light curing(Unilux AC$^{(R)}$) Experimental group 5 : Laser curing($SPECTRUM^{TM}$) + Light curing(Astron XL$^{(R)}$) + Heat treatment (CRC-$100^{TM}$) According to the above classification, we made samples through the curing of Clearfil CR Inlay$^{(R)}$, which is a composite resin for inlay, in a separable cylindrical metal mold and polycarbonate plate. And then, we measured and compared the value of compressive strength, diametral tensile strength and the surface micro hardness of each sample. The results were as follows : 1. Among the experimental groups, group 5 showed the highest value of compressive strength, $157.50{\pm}10.24$ kgf and control group showed the lowest value of compressive strength, $103.93{\pm}21.93$ kgf. Control group showed significant difference with the experimental groups(p<0.001). Group 2 which was treated by the heat showed higher compressive strength than that of group 1 which was not, and there was significant difference between group 1 and group 2(p<0.001). Group 5 which was treated by heat showed higher compressive strength than group 4 which was not, and there was significant difference group 4 and group 5(p<0.001). 2. Among the experimental groups, group 5 showed the highest value of diametral tensile strength, $95.84{\pm}1.97$ kgf and control group showed the lowest value of diametral tensile strength, $81.80{\pm}2.17$ kgf. Control group which was cured by visible light showed higher diametral tensile strength than group 3 which was cured Argon Laser. Group 2 which was treated by heat showed higher compressive strength than that of group 1 which was not, and there was significant difference between group 1 and group 2(p<0.001). Group 5 which was treated by heat showed higher compressive strength than group 4 which was not, and there was a significant difference group 4 and group 5(p<0.001). 3. Among the experimental groups, group 5 showed the highest value of microhardness of top surface, $148.42{\pm}9.57$ kgf and control group showed the lowest value of microhardness, $111.43{\pm}7.63$ kgf. In the case of bottom surface, group 5 showed the highest value of $146.19{\pm}7.62$ kgf, and control group showed the lowest, $104.03{\pm}11.05$ kgf. Group 3 which was cured by Argon Laser showed higher diametral tensile strength than control group which was cured only with a visible light gun. Group 2 which was treated by heat showed higher compressive strength than that of group 1 which was not, and there was a significant difference between group 1 and group 2(p<0.001). Group 5 which was treated by heat showed higher compressive strength than group 4 which was not, and there was a significant difference group 4 and group 5(p<0.001). 4. According to the above results, we took a conclusion that argon laser can be used as a useful unit for curing the composite resin and heat treatment can improve the physical properties of the composite resin inlay.