RESUMO
Orthodontic traction of an impacted dilacerated maxillary central incisor is clinically challenging and often results in a long treatment duration. A case of an unusual dilacerated central incisor with a 90° crown-root angulation and palatally displaced crown is presented herein. Using a single stage open window exposure of the crown on the palatal aspect with light orthodontic traction force, the impacted dilacerated central incisor crown was successfully positioned in alignment with the contralateral incisor.
RESUMO
Polyamide denture base materials are more flexible than the commonly used poly (methyl methacrylate) (PMMA). However polishability of polyamides has not been examined adequately. This study investigated the surface roughness (Ra) and clinical acceptability of samples of a polyamide denture base material and PMMA fabricated by injection moulding and traditional heat processing systems, respectively. Half of each sample surface was polished using the conventional technique (lathe with pumice followed by high shine buffs) and the other half was left unpolished. A profilometer was used to measure Ra along 3 tracks on each surface before and after polishing. Two-way ANOVA was used to compare the two surfaces of the two materials for variations in Ra values. Polyamide denture base material when polished with conventional laboratory technique became more than 7 times smoother whereas processed PMMA when polished became more than 20 times smoother using the same polishing technique. However the surface roughness of polyamide is well within the accepted norm of 0.2 µm Ra. Polyamide produces a clinically acceptable smoothness after conventional polishing by lathe.
