When a patient with a fractured anterior tooth visits the clinic, clinician has to restore the tooth esthetically and quickly. For esthetic resin restoration, clinician can use 'Natural Layering technique' and an index for palatal wall may be needed. In this case report, we introduce pre-restoration index technique on a Class IV defect, in which a temporary filling material is used for easy restoration. Chair-side index fabrication for Class IV restoration is convenient and makes a single-visit treatment possible.

Proteoglycan is highly hydrophilic and negatively charged which enable them attract the water. The objective of study was to investigate the effects of Proteoglycan on microtensile bond strength of dentin adhesives and on architecture of dentin collagen matrix of acid etched dentin by removing the chondroitin sulphate attached on Proteoglycan. A flat dentin surface in mid-coronal portion of tooth was prepared. After acid etching, half of the specimens were immersed in 0.1 U/mL chondroitinase ABC (C-ABC) for 48 h at 37℃, while the other half were stored in distilled water. Specimens were bonded with the dentin adhesive using three different bonding techniques (wet, dry and re-wet) followed by microtensile bond strength test. SEM examination was done with debonded specimen, resin-dentin interface and acid-etched dentin surface with/without C-ABC treatment.

For the subgroups using wet-bonding or dry-bonding technique, microtensile bond strength showed no significant difference after C-ABC treatment (p > 0.05). Nevertheless, the subgroup using rewetting technique after air dry in the Single Bond 2 group demonstrated a significant decrease of microtensile bond strength after C-ABC treatment. Collagen architecture is loosely packed and some fibrils are aggregated together and relatively collapsed compared with normal acid-etched wet dentin after C-ABC treatment. Further studies are necessary for the contribution to the collagen architecture of noncollagenous protein under the various clinical situations and several dentin conditioners and are also needed about long-term effect on bond strength of dentin adhesive.

The purpose of this study was to compare the root canal shaping ability of 4 rotary NiTi instruments in simulated root canals.

For the preparation of thirty two curved root canals, Mtwo instruments using "single length"technique, and Profile, ProTaper Universal, and K3 using crown-down technique (N = 8) were used. All canal samples were prepared by reaching an apical canal size of #30. Pre- and post-instrumentation digital images were recorded and an assessment of canal shape was determined using a computer image analysis program SigmaScan Pro (Systat Software Inc., San Jose, CA, USA). The changes of the dimension of inner walls of canals, (2) the changes of the dimension of outer walls of canals, and (3) the centering ratio were measured at 7 measuring points, and then data were statistically analyzed using one-way ANOVA and Duncan's test. The results were as below;

The root canal shaping ability of Profile was significantly faster than that of other rotary NiTi instruments (p < 0.05).

Results suggest that in the coronal part of canal preparation, active cutting files such as ProTaper Universal may efficiently flare the canal orifice and form a better taper, and in the apical part of the canal, files which have a better centering ability such as Profile may maintain the original canal curvature and reduce the shaping time.

During the last two decades, there has been an increasing interest in the impact of oral health on atherosclerosis and subsequent cardiovascular disease (CVD). To date, some periodontal pathogens including Porphyromonas gingivalis (P. gingivalis) have been reported to be relevant to CVD. Porphyromonas endodontalis (P. endodontalis), which shares approximately 87% sequence homology with P. gingivalis, is mostly found within infected root canals. However, recent studies reveal that this pathogen also resides in the dental plaque or periodontal pocket in patients with periodontitis. It has been shown that P. endodontalis invades human coronary artery endothelial cells (HCAEC) and coronary artery smooth muscle cells (CASMC). To evaluate whether P. endodontalis can participate in the progression of atherosclerosis and CVD, we examined the changes in transcriptional gene expression profiles of HCAEC responding to invasion by P. endodontalis in this study.

The following results were obtained.

Porphyromonas endodontalis was invasive of HCAEC.

Thus, these results show that P. endodontalis presents the potential to trigger and augment atherosclerosis leading to CVD.

The purpose of this study was to evaluate the effect of chlorhexidine (CHX) on microtensile bond strength (µTBS) of dentin bonding systems.

Dentin collagenolytic and gelatinolytic activities can be suppressed by protease inhibitors, indicating that MMPs (Matrix metalloproteinases) inhibition could be beneficial in the preservation of hybrid layers. Chlorhexidine (CHX) is known as an inhibitor of MMPs activity in vitro.

The experiment was proceeded as follows:

At first, flat occlusal surfaces were prepared on mid-coronal dentin of extracted third molars. GI (Glass Ionomer) group was treated with dentin conditioner, and then, applied with 2% CHX. Both SM (Scotchbond Multipurpose) and SB (Single Bond) group were applied with CHX after acid-etched with 37% phosphoric acid. TS (Clearfil Tri-S) group was applied with CHX, and then, with adhesives. Hybrid composite Z-250 and resin-modified glass ionomer Fuji-II LC was built up on experimental dentin surfaces. Half of them were subjected to 10,000 thermocycle, while the others were tested immediately. With the resulting data, statistically two-way ANOVA was performed to assess the µTBS before and after thermocycling and the effect of CHX. All statistical tests were carried out at the 95% level of confidence. The failure mode of the testing samples was observed under a scanning electron microscopy (SEM).

Within limited results, the results of this study were as follows;

In all experimental groups applied with 2% chlorhexidine, the microtensile bond strength increased, and thermocycling decreased the microtensile bond strength (P > 0.05).

2% chlorhexidine application after acid-etching proved to preserve the durability of the hybrid layer and microtensile bond strength of dentin bonding systems.

The purpose of this study was to evaluate the bond strength of a new Single step system with different curing mode composites, and to evaluate the effect of the intermediate resins which have different hydrophilicity on bonding ability by means of the micro shear bond testing and TEM examination for the adhesive interface. The adhesive used in this study was an experimental single step system (Bisco Inc., Schaumburg, IL). Experimental groups were produced by using six kinds of intermediate resin having different hydrophilicity that was hydrophilic, hydrophobic and most hydrophobic resin and as filled or not after applying adhesive. Each experimental group was further divided into two subgroups whether the adhesive was light cured or not. Dual cured composite (Bis Core, Bisco Ltd., Schaumburg, IL) was placed on the adhesive layer as light cure or self cure mode. The results of bond strength were statistically analyzed using one way ANOVA and multiple comparisons are made using Tukey's test at α < 0.05 level.

The results of this study were as follows;

1. The application of intermediate resin did not increase the bond strength for light cured composite.

2. The bond strength of an experimental adhesive with self cured composite was significantly increased by the application of intermediate resin layer.

3. The bond strength of adhesive was irrespective of the cure or not of itself before intermediate resin layer applied.

4. As applied hydrophilic resin layer was, the initial bond strength was higher than both hydrophobic and most hydrophobic one used but there was no significance.

Using a single step adhesive with dual/self cured composite, the incompatibility between both of them should be solved by the application of intermediate hydrophobic resin to reduce the adhesive permeability. However, Single step adhesive can be used in the light cured composite restoration without any decrease of the initial bond strength.

The objectives of this study was to evaluate the durability of 4 resin cements by means of microtensile bond strength test combined with thermocycling method and fractographic FE-SEM analysis.

Experimental groups were prepared according to thermocycling (0, 1,000, 5,000) and the kind of resin cements, those were Variolink II, Multilink, Panavia F 2.0, Rely X Unicem. Flat dentin surfaces were created on mid-coronal dentin of extracted third molars. Then fresh dentin surface was grounded with 320-grit silicon carbide abrasive papers to create uniform smear layers. Indirect composite block (Tescera, Bisco Inc., Schaumburg, IL, USA) was fabricated (12 × 12 × 6 mm³). It's surface for bonding to tooth was grounded with silicon carbide abrasive papers from 180- to 600-grit serially, then sandblasted with 20 - 50 µm alumina oxide. According to each manufacturer's instruction, dentin surface was treated and indirect composite block was luted on it using each resin cement. For Rely X Unicem, dentin surface was not treated. The bonded tooth-resin block were stored in distilled water at 37℃ for 24 hours. After thermocycling, the bonded tooth-resin block was sectioned occluso-gingivally to 1.0 mm thick serial slabs using an Isomet slow-speed saw (Isomet, Buehler Ltd, Lake Bluff, IL, USA). These sectioned slabs were further sectioned to 1.0 × 1.0 mm² composite-dentin beams. The specimens were tested with universal testing machine (EZ-Test, Shimadzu, Japan) at a crosshead speed of 1.0 mm/min with maximum load of 500 N. The data was analyzed using one-way ANOVA and Duncan's multiple comparison test at p ≤ 0.05 level.

Within the limited results, we conclude as follows;

1. The bond strength of Variolink II was evaluated the highest among experimental groups and was significantly decreased after 1,000 thermocycling (p < 0.05).

2. The bond strength of Multilink was more affected by thermocycling than the other experimental groups and significantly decreased after 1,000 thermocycling (p < 0.05).

3. Panavia F 2.0 and Rely X Unicem showed the gradually decreased tendency of microtensile bond strength according to thermocycling but there was no significant difference (p > 0.05).

4. Adhesive based-resin cements showed lower bond strength with or without thermocycling than composite based-resin cements.

5. Variolink II & Multilink showed high bond strength and mixed failure, which was occurred with a thin layer of luting resin cement before thermocycling and gradually increased adhesive failure along the dentin surface after thermocycling.

The bonding performance of resin cement can be affected by application procedure and chemical composition. Composite based-resin cement showed higher bond strength and durability than adhesive based-resin cement.

The purpose of this study is to evaluate the effects of surface treatment and composition of reinforcement material on fracture strength of fiber reinforced composite inlay bridges.

The materials used for this study were I-beam, U-beam TESCERA ATL system and ONE STEP(Bisco, IL, USA). Two kinds of surface treatments were used; the silane and the sandblast. The specimens were divided into 11 groups through the composition of reinforcing materials and the surface treatments.

On the dentiform, supposing the missing of Maxillary second pre-molar and indirect composite inlay bridge cavities on adjacent first pre-molar disto-occlusal cavity, first molar mesio-occlusal cavity was prepared with conventional high-speed inlay bur.The reinforcing materials were placed on the proximal box space and build up the composite inlay bridge consequently. After the curing, specimen was set on the testing die with ZPC. Flexural force was applied with universal testing machine (EZ-tester; Shimadzu, Japan). at a cross-head speed of 1 mm/min until initial crack occurred. The data wasanalyzed using one-way ANOVA/Scheffes' post-hoc test at 95% significance level.

Groups using I-beam showed the highest fracture strengths (p < 0.05) and there were no significant differences between each surface treatment (p > 0.05). Most of the specimens in groups that used reinforcing material showed delamination.

The use of I-beam represented highest fracture strengths (p < 0.05).

This article complies a survey on the replacement of the posterior restorations and accesses possible factors that influence the replacement of posterior restorations.

The data was collected from patients that visited department of conservative dentistry from Dec 1st 2003, to Sep 3rd 2004. Teeth was restricted to posterior permanent teeth. 9 dentists recorded age, gender of patients, tooth location, cavity form and restorative material. They rated marginal adaptation, anatomic form, secondary caries of old restoration by modified Ryge criteria system. The statistical analysis was performed with Chi square test (p < 0.05) for replacement ratio according to patients, tooth factor and One-way ANOVA was performed for comparison of old restoration according to restorative material.

The results were as follows;

1. The female (62%) was statistically higher ratio than the male (38%).

2. The distribution of replacement case according to age, the rate of replacement was in descending order, 20's (38.3%), 40's (16.8%), 30's (15.9%), 10's (11.1%), 50's (9.2%), 60's (8.7%).

3. The rate of replacement was 88% for molar and 12% for premolar (p < 0.05).

4. The rate of replacement was 39% for maxillar and 61% for mandible (p < 0.05).

5. The material of restorations was amalgam (69%), gold inlay (17%), composite resin (13%).

6. In rating system by modified Ryge criteria system on margin adaptation, there was statistically significant difference between amalgam and gold inlay. But on anatomic form and caries, there was no statistically significant difference among the material of restorations.

We investigated the secretion of Interleukin-8 (IL-8) from ginviva and periodontal ligament stimulated with Substance P (SP) and Calcitonin Gene-related Peptide (CGRP). Gingiva (GF), periodontal ligament (PDLF) and pulp (PF) tissues were collected from extracted intact 3rd molars.

Cultured cells were stimulated with different concentrations of SP for 4 hrs, and stimulated with SP, CGRP and Tumor Necrosis Factor-α (TNF-α) for 8 hrs. Then RNase Protection Assay was carried out. ELISA was performed using supernatants of stimulated cells for quantitative analysis of IL-8. Results were assessed using student t-test with significance of P < 0.05.

According to this study, the results were as follows:

IL-8 mRNA was detected in all type of cells studied (PF, GF and PDLF).

Calcitonin Gene-related Peptide (CGRP) increased Interleukin-8 (IL-8) which plays an important role in chemotaxis of neutrophil in Calcitonin Gene-related Peptide (CGRP) gingival tissue, whereas Substance P increased the secretion of IL-8 from periodontal ligament.

This study was performed to investigate the compatibility between 4 dentin adhesives and 4 resin luting cements.

Dentin adhesives used in this study were All-Bond 2 (Bisco Inc., Schaumbrug, IL, USA), Clearfil SE-Bond (Kuraray Medical Inc, Osaka, Japan), Prompt L-Pop (3M Dental Products, St. Paul, MN, USA), One-Up Bond F (Tokuyama corp., Tokyo, Japan). Resin luting cements used in this study were Choice (Bisco Inc., Schaumbrug, IL, USA), Panavia F (Kuraray Medical Inc, Osaka, Japan), RelyX ARC (3M Dental Products, St. Paul, MN, USA), Bistite II DC (Tokuyama corp., Tokyo, Japan). Combination of each dentin adhesive and corresponding resin cement was made to 16 experimental groups.

Flat dentin surfaces was created on mid-coronal dentin of extracted mandibular third molars, then dentin surface was polished with 320-grit silicon carbide abrasive papers.

Indirect resin composite block (Tescera, Bisco) was fabricated. Its surface for bonding to tooth was polished with silicon carbide abrasive papers. Each dentin adhesive was treated on tooth surface and resin composite overlay were luted with each resin cement. Each bonded specimen was poured in epoxy resin and sectioned occluso-gingivally into 1.0 mm thick slab, then further sectioned into 1.0 × 1.0 mm² composite-dentin beams. Microtensile bond strength was tested at a crosshead speed of 1.0 mm/min. The data were analysed by one-way ANOVA and Duncan's multiple comparison tests.

The results of this study were as follows;

2-step self-etching dentin adhesive which has additional bonding resin is more compatible than 1-step self-etching dentin adhesive.

The purpose of this study was to measure the flexural strength and hardness of four core materials in 4 different medias and to evaluate the relationship between the physical properties.

For the flexural strength, the specimens were prepared from each of the following materials: Bisfil Core, Core Max, Fuji IX GP, Miracle Mix and randomly divided into four groups and stored at 37 degree C in the following medias: distilled water for 24 hours (DW/1), distilled water for 30 days (DW/30). 2% NaF for 30 days (NF/30), 0.02N lactic acid for 30 days (LA/30). After storage, the specimens were subjected to flexural strength testing and calculated to flexural modulus.

For hardness testing, specimens were prepared from four materials and storaged in the uniform way. After storage, the specimens were subjected to Vicker's hardness testing.

1. The flexural strength of Core Max were the highest, and the flexural strength of Miracle Mix were the lowest.

2. The hardness of Bisfil Core were the highest.

3. The hardness of Core Max were the highest.

4. The hardness of Miracle Mix were the lowest.

5. 2% NaF and 0.02N lactic acid negatively affected the flexural strength and hardness of four core materials.

The purpose of this study was to evaluate the effect of dual bonding technique by comparing micro-shear bond strength between two different luting methods of resin cement to tooth dentin. Three dentin bonding systems(All-Bond 2, One-Step, Clearfil SE Bond), two temporary cements (Propac, Freegenol) were used in this study.

In groups used conventional luting procedure, dentin surfaces were left untreated. In groups used dual bonding technique, three dentin bonding systems were applied to each dentin surface. All specimens were covered with each temporary cement. The temporary cements were removed and each group was treated using one of three different dentin bonding system. A resin cement was applied to the glass cylinder surface and the cylinder was bonded to the dentin surface. Then, micro-shear bond strength test was performed. For the evaluation of the morphology at the resin/dentin interface, SEM examination was also performed.

Conventional luting procedure showed higher micro-shear bond strengths than dual boning technique. However, there were no significant differences.

The objectiveness of this study was to evaluate whether low-viscosity composite can bond effectively to dentin surface without bonding resin. The low-viscosity composites being 50wt% filler content were made by the inclusion of bonding resin of two self-etching systems(Clearfil SE Bond, Unifil Bond) varied with contents as 0, 10, 20, 30, 40, 50wt%.

Exposed dentin surfaces of extracted 3rd molars are used. Dentin bond strengths were measured. The tests were carried out with a micro-shear device placed testing machine at a CHS of 1mm/min after a low-viscosity composite was filled into an iris cut from micro tygon tubing with internal diameter approximately 0.8mm and height of 1.0mm.

Flexural strength and modulus was increased with the addition of bonding resin.

Low viscosity composite including some functional monomer may be used as dentin bonding resin without an intermediary bonding agent. It makes a simplified bonding procedure and foresees the possibility of self-adhesive restorative material.

The purpose of this study was to evaluate the effect of salivary contamination of teeth on bonding efficacy of self-priming and self-etching DBSs. The materials used were Single Bond(SB, self-priming system, 3M), Unifil Bond(UB, self-etching system, GC), and Scotchbond Multi-Purpose Plus(SM, 3M) as control. Forty five human molars randomly allocated to three groups as dentin bonding systems tested and embedded in epoxy resin. Then the specimens were wet-ground to expose flat buccal enamel surface or flat occlusal dentin surface and cut bucco-lingually to form two halves with slow speed diamond saw. One of them was used under non-contamination, other under contamination with saliva. The bonding procedure was according to the manufacturer's directions and resin composite(Z-100, 3M Dental Products, St. Paul, MN) was built-up on the bonded surface 5mm high. The specimens were ground carefully at the enamel-composite interface with fine finishing round diamond bur to create an hour-glass shape yielding bonded surface areas of 1.5±0.1mm². The specimens were bonded to the modified microtensile testing apparatus with cyanoacrylate, attached to the universal testing machine and stressed in tension at a CHS of 1mm/min.. The tensile force at failure was recorded and converted to a tensile stress(MPa). Mean values and standard deviations of the bond strength are listed in table. One-way ANOVA was used to determine significant difference at the 95% level.

The bond strength of SBMP and SB were not affected by salivary contamination, but that of UB was significantly affected by salivary contamination. These results indicate that DBSs with total etch technique seems less likely affected by salivary contamination in bonding procedure.

Current composites are made with dimethacrylate monomers and silane-treated silica microfillers, either alone or with silane treated glass fillers. The main reasons for clinical failure of dental composites are secondary caries, wear and fracture. Most of practitioner want to get a composite which is more tougher under occlusal stress, less polymerization contraction, and better handling properties in application clinically. The aim of this study was to investigate the influence of resin matrix with various flows on the physical properties such as fracture toughness and degree of conversion of the experimental resins. It was hypothesized that flexible or tough resin composites can be designed by judicious choice of monomer composition.

Various flow resin matrices containing Bis-GMA, UDMA, and TEG-DMA were made by altering the proportion of the monomers. After the unfilled resins were light-cured for different light intensity, the fracture toughness(K_1c) was measured according to ASTM standard using the single edge notched geometry, and degree of conversion(DC) was measured by FTIR. And experimental composites were formulated with variations in the proportion of silanated quartz and strontium glass fillers as 60, 75, and 77wt%. Also, the physical properties of composites with various filler contents were evaluated as same manner. All resulting data were compared by ANOVA/Tukeys test at 0.05 level.

The results were as follows;

1. The degree of conversion of high flow resin containing less Bis-GMA was higher than that of low flow unfilled resin.

2. While the degree of conversion of unfilled resin was increased according to light intensity for polymerization, there was no significant increase with moderate and high light intensity. Also, the fracture toughness was not increased by high light intensity.

3. The fracture toughness was high in the low flow unfilled resin containing higher contents of Bis-GMA.

4. There was a significant increase for fracture toughness and a tendency for degree of conversion to be reduced when the content of fillers was increased.

5. In the experimental composites, the flow of resin matrix did not affected on the fracture toughness, even, which was decreased as increase of viscosity.

These results showed that the physical properties of a dental composite could be attributed to the flow of resin matrix with relative content of monomers. Specific combination of resin monomers should be designed to fulfil the needs of specific indication for use.