RESUMO
Aim: The purpose of this study was to compare the influence of different polishing systems on the surface roughness of nano-hybrid composite resins. Materials and Methods: Fourty samples of acrylic blocks were prepared with cold cure acrylic resin in plastic rings of 1 inch diameter. In each acrylic block, a well of 6mm diameter and 2mm depth was prepared by drilling hole in it using a slow speed micromotor. Tetric N-Ceram™ nano composite is placed in the wells prepared using a plastic instrument and covered with a mylar strip. The samples were then cured for 40s through the mylar strips using LED curing light. 60 samples were divided into 4 groups with 15 samples in each group based on polishing regimen used. Group A - Mylar strip, Group B- PoGo diamond polishers, Group C- prophy brushes and Group D- Super- Snap Rainbow kit. The polished resin composite discs were washed, allowed to dry and kept again in 100% humidity for 24 h before measuring the average surface roughness values (Ra). The surface roughness test was performed using a profilometer and surfaces are seen under scanning electron microscope[SEM]. Statistical analysis: The data were analysed by using one-way ANOVA using SPSS 17.0 software. Results: For all the materials, the smoothest surface was obtained with mylar strip and the roughest with prophy brushes(P< 0.05).Conclusion: Mylar strip produced smoothest surface than other polishing systems.
RESUMO
A thorough knowledge of root canal anatomy and its variations is very important for successful endodontic therapy and it depends upon the locations of all the canals, debridement and proper sealing. At times the clinicians are challenged with variations in morphology of root canal, one of such variations are observed in mandibular first molars. It is well known that both primary and permanent mandibular first molars usually have two roots, one mesial and distal and rarely an additional third root (supernumerary root) , when it is located distolingually to the main distal root is called “radix entomolaris (RE)” and when it is placed mesiobuccaly to the mesial root is called “radix paramolaris (RP) .” This review article attempts to make the dental fraternity aware of this morpho-anatomical variation, prevalence and endodontic management of these teeth thereby making their endodontic treatment successful.