The Effect of Calcium Silicate-Based Materials on Tooth Discoloration and Evaluation of Color Change After Bleaching Treatment: A Spectrophotometric Study.

PURPOSE: To evaluate tooth discoloration after the use of calcium silicate-based materials and to examine the effect of internal bleaching on tooth discoloration. MATERIALS AND METHODS: The specimens were randomly divided into two experimental groups (n = 45) and a control group (n = 6). Cavities were filled with ProRoot MTA (Dentsply) in Group 1 and Biodentine (Septodont) in Group 2. Color measurements were taken with a spectrophotometer before and after the application of materials at 1 week and then at 13, and 6 months. After 6 months, Groups 1 and 2 were divided into three subgroups according to internal bleaching techniques. All color change ratios and lightness differences were calculated using the CIE L*a*b* system. Data were analyzed using repeated ANOVA and the Kruskal-Wallis test (P = .05). RESULTS: There were statistically significant differences between Groups 1 and 2 at all time intervals (P < .05). Group 1 showed more discoloration than Group 2 (P < .05). There were no significant differences between the bleaching agents (P > .05). Additionally, specimens in both groups became lighter than their initial color (P < .05). CONCLUSION: Teeth treated with ProRoot MTA exhibited darkening at 1 week that increased over time, whereas those treated with Biodentine maintained the lightness for 6 months.

Tooth crown discoloration induced by endodontic sealers: a 3-year ex vivo evaluation.

OBJECTIVES: The aim of this study was to evaluate the tooth crown discoloration induced by commonly used and new-generation endodontic sealers after 1 month and 1 and 3 years. MATERIALS AND METHODS: The crowns of 60 extracted incisors were cut and the pulp chambers were cleaned. The specimens were divided randomly into four groups (n = 15 each). Pulp chambers were filled with Pulpispad in group 1, AH26 in group 2, MTA Fillapex in group 3, and EndoREZ in group 4. Specimen color was measured with a spectrophotometer before and after sealer placement. Commission International de L'Eclairage's (CIE's) lighteness (L*), red-green (a*), yellow-blue (b*) color system values and color difference (ΔE) were recorded at 1 month and 1 and 3 years. Data were analyzed using repeated-measures analysis of variance and Tukey's honestly significant difference test (α = 0.05). RESULTS: All sealers caused discoloration. At 1 month, ΔE values were significantly higher in groups 1 and 2 than in groups 3 and 4 (p < 0.05). At 1 year, ΔE values were significantly lower in group 3 than in the other groups (p < 0.05). At 3 years, ΔE values were significantly higher in group 1 than in the other groups (p < 0.05). CONCLUSIONS: All tested sealers induced varying chromatic alterations. After root canal obturation, thorough debridement of sealers from the pulp chamber is essential for the prevention of sealer-induced discoloration. CLINICAL RELEVANCE: Tooth discoloration induced by endodontic materials is a problem for clinicians and patients and may impair the esthetic of endodontically treated teeth. Therefore, evaluation of long-term discoloration effects commonly used, and new-generation endodontic sealers were purposed in this study.

A comparative assessment of the accuracies of Raypex 5, Raypex 6, iPex and iPex II electronic apex locators: An in vitro study.

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.

Fracture Resistance of Premolars Restored Either with Short Fiber or Polyethylene Woven Fiber-Reinforced Composite.

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).

Apical extrusion of sodium hypochlorite activated with two laser systems and ultrasonics: a spectrophotometric analysis.

BACKGROUND: The aim of the present study was to compare the effect of ultrasonically or laser (Nd:YAG or diode) activated irrigation on the irrigating solution extrusion compared to non-activated syringe irrigation. METHODS: Extracted mandibular premolar teeth (n = 48) with single canals were instrumented. The teeth were secured through the lid of an Eppendorf tube filled with 1.0 mL distilled water to collect the apically extruded irrigating solution. The teeth were randomly divided into four groups: non-activated syringe irrigation, diode laser, Nd:YAG laser and passive ultrasonic irrigation (PUI) using 2% NaOCl. The irrigating solution extruded through the apical foramen was collected in the Eppendorf tube and evaluated by a chemical reaction with using a spectrophotometer. The data was analyzed using one-way ANOVA and Tukey's post hoc test (α = 0.05). RESULTS: All the groups showed apically extruded irrigating solution. There were significant differences among the groups (p < 0.05). Nd:YAG laser activated irrigation showed greater extrusion (p < 0.05), while the non-activated syringe irrigation showed less extrusion (p < 0.05). Only the difference between diode laser and PUI was not statistically significant (p > 0.05). CONCLUSION: Within the limitations of this in vitro study, the researchers concluded that non-activated syringe irrigation caused less apically extruded irrigating solution than PUI and LAI using Nd:YAG or diode lasers.

The effect of different adhesive system applications on push-out bond strengths of glass fiber posts.

PURPOSE: Over the past years, the adhesion of fiber posts luted with simplified adhesive systems has been a matter of great interest. The aim of this study was to assess the post retentive potential of a self-adhesive resin cement using different adhesive systems to compare the push-out bond strengths of fiber posts. MATERIALS AND METHODS: The post spaces of 56 mandibular premolar roots were prepared and divided into 4 experimental groups and further divided into 2 subgroups according to testing time (n=7). The fiber posts (Rely X Fiber Post) were luted with a self-adhesive resin cement (RelyX Unicem) and one of the following adhesive systems: no adhesive, a total-etch adhesive resin (Single Bond), a two-step self-etch adhesive resin (Clearfil SE Bond) and a one-step self-etch adhesive resin (Clearfil S3 Bond). Each root was cut horizontally, and 1.5 mm thick six root segments were prepared. Push-out tests were performed after one week or three months (0.5 mm/min). Statistical analysis were performed with three-way ANOVA (α=.05). RESULTS: Cervical root segments showed higher bond strength values than middle segments. Adhesive application increased the bond strength. For one week group, the total-etch adhesive resin Single Bond showed higher bond strength than the self-adhesive resin cement RelyX Unicem applied without adhesive resin at middle region. For 3 months group, the two-step self-etch adhesive resin Clearfil SE Bond showed the highest bond strength for both regions. Regarding the time considered, Clearfil SE Bond 3 months group showed higher bond strength values than one week group. CONCLUSION: Using the adhesive resins in combination with the self-adhesive resin cement improves the bond strengths. The bond strength values of two-step self-etch adhesive resin Clearfil SE Bond improved as time passes.