The indirect technique for making cast restoration requires that dies be as accurate and durable as possible. Currently, stone is the most commonly used material for die. However, it has some problems such as the weakness in its strength and low abrasion resistance. Recently, epoxy resin die systems have become available. The purpose of this study was to examine two commercially available resin die systems and evaluate some characteristics for their clinical performance. This study evaluated the dimensional accuracy of epoxy resins and their wettability with impression materials. In this study, the first experiment was about dimensional accuracy of different die materials. The master model was made of stainless steel. 10 models were made of two epoxy resins (Die-epoxy, Tri-epoxy) and a die stone (Fujirock) each. Occlusal diameter (Dimension I), occluso-gingival height (Dimension II), and interabutment distance (Dimension III) wee measured in each model. Next, the contact angles of die materials with impression materials were observed. The blocks were made of polyether, hydrophilic additional silicone, polysulfide impression materials. By dropping the same amount (0.05ml) of Tri-epoxy, Die-epoxy, and die stone on the blocks, 10 samples of each die material were made. After setting of materials, the contact angles were measured. The results of this study were as follows. 1. The expansion of stone die and the shrinkage of resin dies in occlusal diameter were observed, and stone and Tri-epoxy were expanded and Die-epoxy was shrinked in occluso-gin-gival height. There was little change among materials in interabutment distance (p>0.05). 2. In comparison with the mater model, Tri-epoxy had the least variation in measurement of the three die systems examined. Did-epoxy was next, and die stone showed the greatest variation. 3. The compatibility of die stone for polyether, hydrophilic additional silicone, polysulfide decreased in order, wherease epoxy materials had the decreased compatibility for polyether and polysulfide, hydrophilic additional silicone in order. It was not statistically different between polyether and polysulifide (p>0.05). 4. The contact angles of Tri-epoxy, Die-epoxy, die stone were getting bigger in order.
Epoxy Resins* ; Silicones ; Stainless Steel ; Wettability

The gross tissue specimens are a valuable aid to the teaching of pathology and anatomy. However, traditional methods for storage and handling of them are discouragingly difficult and, recently, minimal surgical resections as well as preoperative interventions make it more difficult to have instructive gross specimens. Plastination is a process of tissue preservation by impregnation with silicone polymers or epoxy resins. The process in our study involves dehydration by cryosubstitution in aceton, defatting, forced impregnation of silicon polymer in a vacuum, curing and finishing. We submitted 40 surgically resected specimens to plastination. The resulting specimens are odorless, relatively dry, durable, life-like, non-hazardous, maintenance-free, and do not deteriorate with time. Plastinated specimens are a useful adjunct to the teaching of pathology, particularly suited for use in small groups, and appropriate method of tissue preservation. They are much preferred to wet preparation and conventional pots by both students and teachers owing to their accessibility, superior illustrative powers, and comparative ease of interpretation.
Dehydration ; Epoxy Resins ; Humans ; Pathology* ; Polymers ; Silicones ; Tissue Preservation ; Vacuum

OBJECTIVES: To compared the effect of different levels of moisture of root canal on the sealing ability after filling with four different types of sealer. MATERIALS AND METHODS: Single-rooted teeth (n = 90) instrumented to and apical size of 0.06 / 45 were randomly assigned to 12 experimental groups (n = 7 per group), positive/negative control groups (n = 3 per group). The teeth of the experimental groups (a. DRY; b. PAPER POINT DRY; c. WET) were obturated with sealer (Group 1-3: Sealapex; Group 4-6: AH plus; Group 7-9: Tubuli-seal; Group 10-12: EndoRez) and warm vertical compaction method. After 7 days in 37degrees C, 100% humidity, the coronal-to-apical microleakage was evaluated quantitatively using a glucose leakage model. The leaked glucose concentration was measured with spectrophotometer at 1, 3, 7, 14, 21, and 30 days. Data were recorded ad mmol/L and statistically analysed with the two-way ANOVA and Duncan test (p = 0.05). RESULTS: Throughout the experimental period Tubuli-seal/WET (Group 9) showed the highest mean cumulative glucose penetration (178.75 mmol/L), whereas AH plus/DRY (Group 4) had the least (20.78 mmol/L). CONCLUSIONS: The results of this study demonstrated that the moisture condition of root canals at the time of obturation and the type of sealer that was used had a significant effect on leakage and sealing ability. Thus drying procedure according to sealer types is a critical step and should not be missed in endodontic treatment.
Calcium Hydroxide ; Composite Resins ; Dental Pulp Cavity ; Epoxy Resins ; Glucose ; Humidity ; Root Canal Filling Materials ; Salicylates ; Tooth

OBJECTIVETo evaluate the sealing properties of three resin- based sealers, EndoREZ, RealSEAL and RealSEAL SE.

METHODSForthy-eight extracted human anterior teeth with single root and canal were prepared using ProTaper files with crown-down technique to F3. The teeth were filled with three sealer respectively with hot gutta- percha vertical condensation technique simulating the clinical situation. Leakage quantity was detected using computerized fluid filtration meter with 10 samples in each group. The cross section morphology of apical parts of roots of 5 mm was observed with scanning electron microscope and transmission electron microscope in 3 samples of each group, respectively.

RESULTSThe leakage quantity of EndoREZ, RealSEAL and RealSEAL SE were (2.61±0.60), (1.43±0.11) and (1.76±0.18) µl/min, respectively. The gaps between the the sealer and the canal wall were increased in in order of RealSEAL, RealSEAL SE and EndoREZ. No obvious demineralized dentin under EndoREZ and the smear layer was not completed removed. The partly demineralized dentin was observed under RealSEAL and the smear layer was totally removed. The partly demineralized dentin was seen under RealSEAL SE and the majority of smear layer was removed.

CONCLUSIONSAmong the three resin- based sealers, RealSEAL has the best sealing properties, followed by RealSEAL SE and EndoREZ.

Composite Resins ; Dental Leakage ; Dentin ; Epoxy Resins ; Gutta-Percha ; Humans ; Pit and Fissure Sealants ; Root Canal Filling Materials ; Tooth ; Tooth Root

This study was performed to assess the radiopacity of a variety of root canal sealers according to the specification concerning root canal sealers. Ten materials including Tubli-Seal(TM), Kerr Pulp Canal Sealer(TM), AH 26(R), AH plus(R), AH plus jet(TM), Ad sea l(TM), Sealapex(TM), NOGENOL(TM), ZOB seal(TM), Epiphany(TM) and dentin were evaluated in this study. In the first part, densitometric reading of an each step of aluminum step wedge on occlusal film was performed at different voltage and exposure time. In the second part, ten specimens were radiographed simultaneously with an aluminum step wedges on the occlusal films under decided condition. The mean radiographic den sity values of the materials were transformed into radiopacity expressed equivalent thickness of aluminum (mm Al). The following results were obtained. 1. Among the various conditions, the appropriate voltage and exposure time that meet the requirement density was 60 kVp at 0.2 s. 2. All of the materials had greater radiopacity than 3 mm Al requirement of ANSI/ADA specification No. 57 (2000) and ISO No. 6876 (2001) standards. 3. The radiopacity of materials increased as thickness of materials increased. 4. The mm Al value of each specimen at 1mm in thickness has a significant difference in the statistics. It suggests that root canal sealers have a sufficient radiopacity that meet the requirement.
Aluminum ; Dental Pulp Cavity ; Dentin ; Epoxy Resins ; Root Canal Filling Materials

BACKGOUND: Bisphenol-A (2,2-bis (4-hydroxyphenyl)propane, BPA) is suspected to be an endocrine disruptor. BPA is a component of polycarbonate (PC), polysulfone (PS), and epoxy resins. PC is used as a material in the case header. Evaluation of BPA release from hemodialyzers may be very important, because BPA released from hemodialyzers is directly introduced into blood circulation. We examined the plasma levels of BPA before and after a hemodialysis session to evaluate the degree of BPA in patients with regular hemodialysis. METHODS: Ten patients undergoing regular hemodialysis were enrolled. We used cellulosynthetic dialyzer (Hemophan(R)-Alwall GFS Plus 2) and Bisphenol A concentration in plasma that had been taken before and after a hemodialysis session determined by gas chromatography-mass spectrometry (GC/MS) analysis. RESULTS: Plasma BPA levels before and after a hemodialysis session were 0.02+/-0.05 ng/mL and 0.16+/-0.15 ng/mL respectively. Plasma BPA levels after a hemodialysis session were significantly higher than those before hemodialysis. There were no significant correlations between plasma BPA level and several clinical parameters such as Kt/V, duration of hemodialysis, ultrafiltraion, blood flow, and age. CONCLUSION: Very small amounts of BPA were released from the cellulosynthetic hemodialyzer during a hemodialysis session. BPA doesn't seem to accumulate in the body of patients undergoing regular hemodialysis using cellulosynthetic hemodialyzer.
Blood Circulation ; Epoxy Resins ; Gas Chromatography-Mass Spectrometry ; Humans ; Kidneys, Artificial ; Plasma ; Renal Dialysis*

Epoxy resins has been used as a adhesive material in industry. Toxic effects for epoxy resin are known as respiratory, dermatologic, ophthalmologic and allergic symptoms. Ingestion of epoxy resin has been known to induce moderate toxic effect, but reports are very rare. Toxic injury due to ingestion in gastrointestinal tract is usually caused by suicidal attempt or incidental ingestion in young ages and alcoholics. Herein, we report a case of diffuse mucosal injury in upper gastrointestinal tract caused by thermal injury from epoxy resin with a review of relevant literatures.
Adhesives ; Alcoholics ; Eating ; Epoxy Resins ; Gastrointestinal Tract ; Humans ; Upper Gastrointestinal Tract*

The purpose of this study was to evaluate the effect of soft chelating irrigant on the sealing ability of root fillings by using a glucose leakage test. A total of 45 single-rooted teeth were selected for the study. The teeth were decoronated leaving a total length of 13mm. The root canals prepared using K3 NiTi rotary instruments to an apical dimension of size 45(0.06 taper). The specimens were then randomly divided into 3 experimental groups of 13 roots each and 2 control groups of 3 roots each. Specimen in each group were prepared with different irrigation protocols : group 1, 2.5% NaOCl; group 2, 2.5% NaOCl and 17% EDTA; group 3, 2.5% NaOCl and 15% HEBP. The root canals were filled with gutta-percha and AH Plus sealer using lateral condensation. After 7 days in 37degrees C, 100% humidity, the coronal-to-apical microleakage was evaluated quantitatively using a glucose leakage model. The leaked glucose concentration was measured with spectrophotometry at 1, 4, 7, 14, 21 and 28 days. There was a tendency of increase in leakage in all experimental groups during experimental period. HEBP-treated dentin showed no significant difference with EDTA-treated dentin during experimental period. From the 21th day onward, HEBP-treated dentin showed significantly lower leakage than smear-covered dentin. HEBP-treated dentin displayed a similar sealing pattern to EDTA-treated dentin and a better sealing ability than smear-covered dentin. Consequently, a soft chelator(HEBP) could be considered as the possible alternative to EDTA.
Dental Pulp Cavity ; Dentin ; Edetic Acid ; Epoxy Resins ; Glucose ; Gutta-Percha ; Humidity ; Root Canal Filling Materials ; Smear Layer ; Spectrophotometry ; Tooth

Biomechanical preparation of root canals with accentuated curvature is challenging. New rotatory systems, such as Reciproc, require a shorter period of time to prepare curved canals, and became a viable alternative for endodontic treatment of teeth with root dilaceration. Thus, this study aimed to report a clinical case of endodontic therapy of root with accentuated dilaceration using Reciproc single-file system. Mandibular right second molar was diagnosed as asymptomatic irreversible pulpitis. Pulp chamber access was performed, and glide path was created with #10 K-file (Dentsply Maillefer) and PathFile #13, #16 and #19 (Dentsply Maillefer) up to the temporary working length. The working length measured corresponded to 20 mm in the mesio-buccal and mesio-lingual canals, and 22 mm in the distal canal. The R25 file (VDW GmbH) was used in all the canals for instrumentation and final preparation, followed by filling with Reciproc gutta-percha cones (VDW GmbH) and AH Plus sealer (Dentsply Maillefer), using thermal compaction technique. The case has been receiving follow-up for 6 mon and no painful symptomatology or periapical lesions have been found. Despite the difficulties, the treatment could be performed in a shorter period of time than the conventional methods.
Dental Pulp Cavity ; Endodontics ; Epoxy Resins ; Follow-Up Studies ; Gutta-Percha ; Molar ; Pulpitis ; Root Canal Filling Materials ; Tooth

Produced in large-scale since the 1950s, epoxy resins have been used diversely, and new uses are continuing to be found and developed so that the accompanying risks of dermatitis have been spread to new industries such as construction and road building. Epoxy resin, irritants and allergens, cause both direct and airborne contact dermatitis, and occupational dermatitis, This was observed shortly after they were introduced. We report a case of airborne allergic contact dermatitis by an epoxy resin in an antiskid-surfacing worker. A 46-year-old Korean male presented with symmetrical eczematous lesions on exposed areas. A Patch test revealed positive reactions to epoxy resin 1% and their own material, and the symptoms cleared when he changed work environments.
Allergens ; Dermatitis ; Dermatitis, Allergic Contact* ; Dermatitis, Contact ; Dermatitis, Occupational ; Epoxy Resins ; Humans ; Irritants ; Male ; Middle Aged ; Patch Tests