Among dental traumas, horizontal root fractures are relatively uncommon injuries. Proper initial management and periodical evaluation is essential for the successful treatment of a root-fractured tooth. If pulpal necrosis develops, endodontic treatment is indicated, exclusively for the coronal fragment. Fragment diastases exert a great influence on healing at the fracture line and on pulpal necrosis. An adequately treated root-fractured tooth has a good prognosis. This case report describes the treatment and 2-yr follow up of 3 maxillary central incisors, first with horizontal root fracture, second with horizontal root fracture and avulsion, and third with horizontal root fracture and lateral luxation. All three cases were treated with mineral trioxide aggregate (ProRoot, Dentsply). During 2 yr of follow-up evaluation, the root-fractured teeth of the present patients were well retained in the arch, showing periodontal healing, even after endodontic treatment.

Although several methods including composite resin restoration and microabrasion have been used for management of white spot lesion, tooth jewelry can be considered as another noninvasive option. This case report describes the management of white spot lesions by using tooth jewelry. This report also highlights the patients' preference for tooth jewelry as an esthetic concern.

In this study we evaluated the influence of both the thickness of residual enamel and the color of the composite resins applied to lingual surface on the labial surface color.

Background plates were made by randomly (A1, A2, A6D, B1, B2, B3, C1, C2, C6D) selected colors of Filtek Supreme (3M ESPE, St. Paul, U.S.A.) composite resin.

Crown portion of 9 maxillary central incisors were cut off and embedded with acrylic resin except labial surface. Samples of average thickness of 2.2 mm were obtained after cutting it in a thickness of 2.5 mm from the labial surface and sandpaper polish.

The shade of composite resin background was measured using Spectrophotometer (Spectrolino® GretagMacbeth, Regensdorf, Switzerland). And CIE L^*a^*b^* value of 2.2 mm thickness tooth samples were measured on the 9 composite resin backgrounds. And then, the cutting side of tooth samples was ground to the extent of 1.9 mm, 1.6 mm, 1.3 mm, 1.0 mm and placed on composite resin backgrounds and measured L^*a^*b^* values with the same method.

In all samples, L^* value and b^* value seemed to have a tendency of decreasing as thickness of tooth sample becomes thinner regardless of background colors (p < 0.05). But, a^* value didn't show the significant differences depending on the thickness.

The objective of this study was to evaluate the effect of color measuring instrument by measuring the color of dental composite resins.

Nine shade light cured composite resin disks were prepared (diameter : 15 mm, thickness : 4 mm). CIE L^*a^*b^* color scale of each disk was measured with 3 different types of spectrophotometer [MiniScan XE plus (Model 4000S, Hunter Lab, USA), CM-3500d (Minolta, Japan) and Specbos 2100 Miniature VIS Reflection spectrometer (Serial No: 319416, JETI Technishe VIS Instrumentic GmbH, Germany)]. Miniscan XE Plus and CM-3500d using identical measuring geometry with different size of viewing aperture. But Specbos 2100 using different measuring geometry.

Within the limitation of this study, there were color difference (ΔE^*) from 2.4 to 7.8 between Miniscan XE Plus and CM-3500d, but L^*, a^*, b^* values showed the high correlation. However, there were great color difference (ΔE^*) in the extent of about 20 between instruments with the different measuring geometry.

Therefore, color scale measured by color measuring instrument should be used as a relative value rather than an absolute value in the field of dentistry.

This study analyzed the influence of dental adhesive/primer on the bond strength between indirect resin composite and the resin cement.

Seventy disc specimens of indirect resin composite (Tescera Dentin, Bisco) were fabricated. And bonding area of all specimens were sandblasted and silane treated for one minute. The resin cements were used with or without application of adhesive/primer to bonding area of indirect resin restoration: Variolink-II (Ivoclar-Vivadent): Exite DSC, Panavia-F (Kuraray): ED-Primer, RelyX Unicem (3M ESPE): Single-Bond, Duolink (Bisco): One-step, Mulitlink (Ivoclar-Vivadent): Multilinh Primer.

Shear bond strength was measured by Instron universal testing machine.

Adhesive application improved shear bond strength (p < 0.05). But Variolink II and Panavia-F showed no statistically significant difference according to the adhesive application.

With the above results, when resin inlay is luted by resin cement it seems that application of dental adhesive/primer is necessary in order to improve the bond strength.

The purpose of this study was to evaluate the color stability of resin cements with accelerated test. Four dual curing resin cements: Panavia-F (KURARAY), Duolink (BISCO), Variolink-II (Ivoclar Vivadent), and RelyX Unicem (3M ESPE) and 1 self curing resin cement: Resiment CE (j. l. Blosser) were used in this study. In control group, Gradia Anterior (GC) composite resin and Tescera Dentin (Bisco) indirect composite were used. Ten disk shape specimens were made from each resin cement. The specimens were subjected to an accelerated aging process in a refrigerated bath circulator at 60℃ for 15 and 30 days. Spectrophotometric analyses were made before and after 15 days and 30 days of accelerated aging time.

The color characteristics (L^*, a^*, b^*) and the color difference (ΔE^*) of the specimens before and after immersion were measured and computed.

Regardless of type of the resin cements, L^* value was decreased and a^* value was increased, but there were no significant difference. But b^* value was increased significantly (p < 0.05). Tescera inlay showed least color change (p < 0.05), but Gradia showed notable color change after 15 days.

After 30 days on accelerated aging, ΔE^* value was increased (Panavia-F < Variolink-II < Resiment CE < Duolink < Unicem) (p < 0.05), but there were no significant difference among Panavia-F, Variolink-II, and Resiment CE groups. After 30 days of accelerated aging, ΔE^* value of all resin cements were greater than 3.0 and could be perceived by the human eye.

This study was done to evaluate the reliability of the digital color analysis system (ShadeScan, CYNOVAD, Montreal, Canada) for dentistry.

Sixteen tooth models were made by injecting the A2 shade chemical cured resin for temporary crown into the impression acquired from 16 adults. Surfaces of the model teeth were polished with resin polishing cloth. The window of the ShadeScan handpiece was placed on the labial surface of tooth and tooth images were captured, and each tooth shade was analyzed with the ShadeScan software. Captured images were selected in groups, and compared one another.

Two models were selected to evaluate repeatability of ShadeScan, and shade analysis was performed 10 times for each tooth.

And, to ascertain the color difference of same shade code analyzed by ShadeScan, CIE L^*a^*b^*values of shade guide of Gradia Direct (GC, Tokyo, Japan) were measured on the white and black background using the Spectrolino (GretagMacbeth, USA), and Shade map of each shade guide was captured using the ShadeScan.

There were no teeth that were analyzed as A2 shade and unique shade. And shade mapping analyses of the same tooth revealed similar shade and distribution except incisal third.

Color difference (ΔE^*) among the Shade map which analyzed as same shade by ShadeScan were above 3.

Within the limits of this study, digital color analysis instrument for dentistry has relatively high repeatability, but has controversial in accuracy.

The most scientific and reliable method for deciding the tooth color is the instrumental measurement. However, such color measuring instrument shows the difference of the measuring value according to the diversified measuring condition.

This study was conducted to evaluate what effect of the labial surface irregularity of the tooth to the result of the color measured by spectrometer.

11 models of the teeth were made by injecting the A2 shade Luxatemp Automix Plus (DMG, Germany) into the impression acquired from 11 adults. Standard disk samples (15 mm diameter, 7 mm thickness) were made with same material. CIE L^*a^*b^* value was measured at the incisal, central, and gingival area of the central incisor, lateral incisor, canine and first premolar using Specbos 2100 (JETI, Germany) spectrometer. Color difference was calculated between labial surface and standard samples.

Among all models of the teeth, L^* and b^* value showed the reducing tendency as they go toward the gingival area, but a^* value showed the increasing tendency.

Color difference between model teeth and standard samples showed the most difference at the incisal area, but the gingival area showed the least difference. And the canine showed the least color difference from the comparison of standard sample, and the central incisor showed the highest difference (p < 0.01).

Although the visually detectable difference of the measuring value showed notably depending on the type and measured area (p < 0.05), L^* and a^* value showed notable differences depending more on the measured areas than on the type of the teeth.

The purpose of this study is to develope new dental color-space system. Twelve kinds of dental composites and one kind of dental porcelain were used in this study. Disk samples (15 mm in diameter, 4 mm in thickness) of used materials were made and sample's CIE L^*a^*b^* value was measured by Spectrocolorimeter (MiniScan XE plus, Model 4000S, diffuse/8° viewing mode, 14.3 mm Port diameters, Hunter Lab. USA). The range of measured color distribution was analyzed. All the data were applied in the form of T### which is expression unit in CNU Cons Dental Color Chart.

The value of L^* lies between 80.40 and 52.70. The value of a^* are between 10.60 and 3.60 and b^* are between 28.40 and 2.21. The average value of L^* is 67.40, and median value is 67.30. The value of a^* are 2.89 and 2.91 respectively. And for the b^*, 14.30 and 13.90 were obtained. The data were converted to T### that is the unit count system in CNU-Cons Dental Color Chart. The value of L^* is converted in the first digit of the numbering system. Each unit is 2.0 measured values. The second digit is the value of a^* and is converted new number by 1.0 measured value. For the third digit b^* is replaced and it is 2.0 measured unit apart. T555 was set to the value of L^* ranging from 66.0 to 68.0, value of a^* ranging from 3 to 4 and b^* value ranging from 14 to 16.

The objectives of this study were to evaluate the effect of surface roughness on the surface color and translucency of the composite resins.

Two composite resins (Esthet-X, Dentsply, Milford, USA and Charisma, Kulzer, Domagen, Germany) were used to investigate the surface color. Charisma was used to investigate the translucency. 40 disc samples (diameter: 8 mm, thickness: 5 mm) were made by each product to measure the surface color. Polymerized each sample's one side was treated by Sof-Lex finishing and polishing system (Group C, M, F, SF). 40 disc samples (diameter: 6 mm, thickness: 1 mm) were prepared to measure the opacity. 1 mm samples were ground one side with #600, #1000, #1500 and #2000 sandpapers. CIE L*a*b* values of each 5 mm thickness samples, and XYZ values of 1 mm thickness samples on the white and black background were measured with spectrophotometer (Spectrolino, GretagMacbeth, Regensdorf, Switzerland).

Mean surface roughness (Ra) of all samples before and after surface treatment was measured using the Surface Roughness Tester SJ-301 (Mytutoyo, Tokyo, Japan).

Regardless of type and shade of the composite resin, L* values measured in group C were higher than others (p < 0.05), and L* value decreased as the Ra value decreased except B3 shade of Esthet-X. But there were no significant difference in a* values among groups. In control group and SF, highest b* values were measured (p < 0.05), except B1 shade of Esthet-X.

Contrast ratio decreased as the Ra value decreased (p < 0.05).

With the above results, difference of surface roughness has influence on surface color and translucency of dental composite resins.