Regardless of restoration technique, fibre reinforcement of composite restorations decreased cusp movement in molar teeth with MOD and endodontic access cavities but did not affect fracture strength.

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Background/purpose Usage of barrier materials is an important step in revascularization procedure. One of the undesired properties of these barrier materials is to cause coronal tooth discoloration. The aim of this in vitro study was to evaluate the tooth discoloration induced by ProRoot MTA (PMTA), Biodentine, and MM-MTA, as well as the efficacy of internal bleaching on this discoloration. Materials and methods Forty-two maxillary incisor teeth were prepared. Triple antibiotic paste (TAP) was placed in the root canals and incubated for 3 weeks. After removing the TAP, blood embedded spongostans were inserted into the root canals, and PMTA, Biodentine, or MM-MTA was placed over them. The teeth were incubated for 4 weeks at 37 °C; then, the internal bleaching agent was sealed for one week. The tooth color was measured throughout the study and the color change values (ΔE) of each specimen were calculated, and the data was statistically analyzed using the one-way ANOVA and Tamhane's T2 tests. Results The TAP significantly decreased the luminosity of the teeth ( p < 0.05); however, no significant differences were observed between the tooth discolorations induced by the PMTA, Biodentine, and MM-MTA ( p > 0.05). The teeth in the Biodentine group were more whitened than those of the PMTA and MM-MTA groups ( p < 0.05). Conclusion Although the PMTA, Biodentine, and MM-MTA caused similar color alterations in the teeth, more bleaching was observed on those teeth discolored using TAP + blood + Biodentine.

The aim of this study was to evaluate the efficacy of Twisted File (TF) Adaptive, Reciproc, and ProTaper Universal Retreatment (UR) System instruments for removing root-canal-filling. Sixty single rooted teeth were decoronated, instrumented and obturated. Preoperative CBCT scans were taken and the teeth were retreated with TF Adaptive, Reciproc, ProTaper UR, or hand files (n=15). Then, the teeth were rescanned, and the percentage volume of the residual root-canal-filling material was established. The total time for retreatment was recorded, and the data was statistically analyzed. The statistical ranking of the residual filling material volume was as follows: hand file=TF Adaptive>ProTaper UR=Reciproc. The ProTaper UR and Reciproc systems required shorter periods of time for retreatment. Root canal filling was more efficiently removed by using Reciproc and ProTaper UR instruments than TF Adaptive instruments and hand files. The TF Adaptive system was advantageous over hand files with regard to operating time.

To assess the effect of post-space treatment with chelating agents on the push-out bond-strength of a glass fiber post-system. Fortyeight human teeth were decoronated. The roots were prepared to size 40 and obturated. The post-spaces were prepared with PeesoReamer drills. The post-spaces were irrigated with (i) NaOCl and EDTA with chlorhexidine (QMix), (ii) NaOCl and EDTA, (iii) NaOCl and Citric acid, (iv) NaOCl and saline as a control group. i-TFC glass fiber posts were then luted with i-TFC bond system. The samples were horizontally sectioned. The displacement resistance was measured. Push-out bond-strength (MPa) was calculated. Data were analyzed. NaOCl/QMix group showed highest values to dentine whereas NaOCl/Citric acid group showed lowest values. i-TFC post-system demonstrated equal bond strength values when post-space treated with either NaOCl/EDTA or NaOCl/Saline. It can be concluded that post-space could be treated with NaOCl and QMix in order to increase adhesion of i-TFC post-system to rootdentine.