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PURPOSE: The aims of this study were to examine the accuracy of iPex II and to compare it with those of Raypex 5, Raypex 6 and iPex electronic apex locators (EALs). MATERIALS AND METHODS: Thirty fresh human mandibular premolar teeth were used in this study. Crown segments were cut and root canals were coronally flared. A #10 K-file was inserted until its tip can be seen within apical foramen to determine actual working length (AWL). Teeth were embedded in alginate and each multi-frequency EALs were randomly tested to determine the electronic working length (EWL). Differences between AWLs and EWLs were statistically compared. RESULTS: No significant differences were found between four EALs. EWL measurements by Raypex 5 were accurate in 64.29%, Raypex 6 in 53.58%, iPex in 64.29% and iPex II in 50% of the specimens, within the range of ±0.5 mm from the AWL. CONCLUSION: Within the limitations of this in vitro experiment, our findings indicate that the accuracy of working length measurements calculated with iPex II was similar to those of other multi-frequency EALs used in this study.

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OBJECTIVE: To compare the fracture resistance of endodontically treated maxillary premolars with one remaining cavity wall restored either with short fiber-reinforced composite or polyethylene woven fiber-reinforced composite. MATERIALS AND METHODS: Forty-eight maxillary premolars were endodontically treated and randomly assigned to four groups (n = 12). Palatal cusp was removed, buccal wall was remained. In groups 1 to 3, standardized cavities were prepared in the palatal canal entrances. In group 1, short fiber-reinforced composite was used for restoration both of deep cavity and coronal part. In group 2, short fiber-reinforced composite was placed inside the deep cavity and core part of the restoration. Coronal restoration was restored by using conventional filler composite. In group 3, both deep cavities and coronal parts were built up by using conventional filler composite. In group 4, post space was prepared in the palatal canal. Polyethylene woven fiber-reinforced composite post then was placed into post space and the coronal part was restored by using conventional filler composite. Specimens were placed into a universal testing machine. The fracture loads were recorded and analyzed statistically using one-way ANOVA (α = 0.05). Fracture patterns were analyzed by using Chi-square test (α = 0.05). RESULTS: No statistically significant difference was found in fracture strength (p > 0.05). Group 1 exhibited the highest and group 4 exhibited the lowest incidence of restorable fracture (p < 0.05). CONCLUSIONS: The restoration of severely weakened premolar teeth with the use of short fiber-reinforced composite might have advantages over conventional filler composite or polyethylene woven fiber-reinforced composite techniques. CLINICAL SIGNIFICANCE: The results of this in vitro study will be helpful to understand reinforced composite materials for restoring endodontically treated maxillary premolars. (J Esthet Restor Dent 28:412-418, 2016).

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The aim of this study was to evaluate tooth discoloration after the use of root canal sealers and the effect of internal bleaching on sealer discoloration. The crowns of 56 incisors were cut and randomly filled with four sealers (n = 14): Pulpispad, AH26, MTA Fillapex, EndoREZ. The colour measurement was taken with a spectrophotometer prior and after placement of sealers. Colour changes (ΔE) were recorded after 4 weeks then sealers were removed and an internal bleaching treatment was performed. After bleaching treatment colour changes (ΔE) were measured. Data were analysed using ANOVA and Tukey's test (α = 0.05). All tested sealers induced varying chromatic alterations. Pulpispad showed statistically more discoloration than other sealers (P < 0.05). After bleaching, EndoREZ showed statistically more bleaching ratio than MTA Fillapex and AH26 (P < 0.05). Internal bleaching was efficient in discoloured teeth induced by root canal sealers.

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The purpose of this study was to evaluate some physical and chemical properties of MTA incorporated with antibacterial silver zeolite (SZ). 0%, 0.2% or 2% mass fraction of SZ was added to MTA powder. The amounts of calcium released from the specimen in deionized water were measured with an atomic absorption spectrophotometer. The setting times of the samples were evaluated using Gilmore-type needles. For solubility and water absorption tests, the samples were placed in a cylindrical polystyrene-sealed container. At 7 days, the samples were removed from solutions and blotted dry for solubility and water absorption test. The highest calcium release was detected in 2% SZ MTA at 24 h. The addition of 2% SZ to MTA reduced the setting time statistically (p<0.05). 2% SZ MTA was significantly more soluble than MTA and 0.2 % SZ MTA (p<0.05). Further research is needed prior to clinical use of MTA with incorporated SZ.

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