The Influence of Different Obturation Systems on the Fracture Resistance of Endodontically Treated Roots. An in Vitro Study

This study aimed to compare the fracture resistance of endodontically treated roots filled by different obturation systems. Material and methods: Ninety-six upper central incisors were used and decoronated, retaining 12 mm of the roots. On the basis of obturation systems, the roots were divided into 4 groups (n=24): Group1 (COGR): control group (unprepared, unfilled), Group 2 (AVGR): ActiV GP points/ActiV GP sealer, Group3 (GPGR): Gutta percha points/AH plus sealer, and Group4 (GAGR): Gutta percha points/ActiV GP sealer. The last three groups were obturated with the single cone technique. The roots were then stored in 100% relative humidity at 37 °C for 2 weeks. A vertical compressive force was exerted with a universal testing machine until a fracture occurred. Data were statistically analyzed with one-way ANOVA. Results: Mean (SD) failure loads for groups ranged from 920.51 ± 210.37 to 1113.44 ± 489.42 N. The fracture resistance between the different study groups indicated no statistical difference. Conclusions: ActiV GP system did not exert a significant effect on the fracture resistance of endodontically treated teeth

The Influence of Different Obturation Systems on the Fracture Resistance of Endodontically Treated Roots. An in Vitro Study

This study aimed to compare the fracture resistance of endodontically treated roots filled by different obturation systems. Material and methods: Ninety-six upper central incisors were used and decoronated, retaining 12 mm of the roots. On the basis of obturation systems, the roots were divided into 4 groups (n=24): Group1 (COGR): control group (unprepared, unfilled), Group 2 (AVGR): ActiV GP points/ActiV GP sealer, Group3 (GPGR): Gutta percha points/AH plus sealer, and Group4 (GAGR): Gutta percha points/ActiV GP sealer. The last three groups were obturated with the single cone technique. The roots were then stored in 100% relative humidity at 37 °C for 2 weeks. A vertical compressive force was exerted with a universal testing machine until a fracture occurred. Data were statistically analyzed with one-way ANOVA. Results: Mean (SD) failure loads for groups ranged from 920.51 ± 210.37 to 1113.44 ± 489.42 N. The fracture resistance between the different study groups indicated no statistical difference. Conclusions: ActiV GP system did not exert a significant effect on the fracture resistance of endodontically treated teeth

Influence of Diode Laser for the Treatment of Dentin Hypersensitivity on Microleakage of Cervical Restorations

Noncarious cervical lesions (NCCLs) are a common clinical finding often linked with dentin hypersensitivity (DH). Aim. The aim of the study was to evaluate the influence of diode laser for the treatment of DH on microleakage of subsequent NCCL restorations. Materials and Methods. Forty-eight extracted human premolars were collected. All teeth received standardized cervical preparation on both the buccal and palatal surfaces and were randomly divided into three groups (n=16) according to the restorative material used: nanohybrid composite resin (CR), resin-modified glass ionomer (RMGI), and conventional glass ionomer (GIC). The prepared cavities on the palatal surfaces were treated by diode laser using SIROlaser Blue (Sirona Dental Systems, Bensheim, Germany) prior to restoration, while preparations on the buccal surfaces were directly restored. After thermocycling, the teeth were immersed in methylene blue dye for microleakage evaluation under 40x magnification at both occlusal and cervical margins. The Kruskal-Wallis test followed by the Bonferroni tests was conducted to determine inter- and intragroup differences (P<0.05). Results. All restorative materials tested showed some degree of microleakage with no statistically significantly different scores with or without the use of laser desensitization prior to restorative treatment. Group CR showed the least microleakage, followed by group RMGI, while group GIC showed the highest. Cervical margins showed greater microleakage than the occlusal margins where the difference was statistically significant in the RMGI group without laser pretreatment (P=0.006) and in both groups CR (P=0.02) and RMGI (P=0.006) with the laser pretreatment. Conclusion. Application of diode laser for the treatment of DH prior to the restoration of teeth with NCCL did not affect the microleakage of all the restorative materials tested. All the materials showed some degree of microleakage, which was higher in gingival margins compared to occlusal margins. The resin composite shows the least microleakage among all the tested materials

Effects of Different Adhesive Systems and Orthodontic Bracket Material on Enamel Surface Discoloration: An In Vitro Study

The aim of this in vitro study was to assess the effect of the type of orthodontic brackets and adhesive systems on enamel discoloration. The baseline color of the buccal surfaces of 50 extracted human premolars was recorded using a spectrophotometer according to the CIE Lab system. The teeth were randomly divided into five groups according to the bracket type and adhesive system used: Group A: metal brackets + a Three-step etch and rinse adhesive (E&R); Group B: metal brackets + a two-step self-adhesive adhesive (SE); Group C: ceramic brackets + (E&R); Group D: ceramic brackets + (SE); Group E: no bracket bonding, serving as a control. All teeth were thermocycled, the brackets were debonded, and the enamel surfaces were finished and polished. The tooth color was then re-assessed, and the change in color (∆E*) was calculated. Pairwise comparisons revealed significant differences in favor of ceramic brackets (ΔE = 3.77 ± 3.60; p = 0.009) and (E&R) (ΔE= 3.52 ± 2.45; p = 0.008). A significant difference was found among the different groups, with group C having the least change in color (ΔE = 2.00 ± 0.89) and group B having the highest (ΔE = 8.42 ± 5.66). Both the type of orthodontic bracket and adhesive system influenced tooth color change. The teeth bonded with ceramic and E&R had the least effect on color changes, whereas teeth bonded with metal and SE showed the highest color changes after debonding