RESUMEN
Anchorage control during the correction of severely crowded dentitions has always been a source of concern during orthodontic therapy. The Nance palatal arch (NPA) has, in the past, been widely used for reinforcing anchorage in such cases. Modifications of the NPA have been reported for use as a fixed functional appliance or for molar distalization. Herein, a simple, effective modification of the conventional NPA is introduced incorporating two power arms, which can be used for unravelling of anterior crowding at the same time effectively augmenting molar anchorage.
RESUMEN
Background: Newer available composite resin adhesives have chromatic agents that change their color during setting from pink to colorless. It has an advantage of easy flash removal thus reducing the amount of plaque accumulation and helping patients to maintain better hygiene. Aim: The aim of the present study was to compare shear bond strengths of light-cure orthodontic bonding agents, namely glass ionomer (FujiOrthoLC, GC Orthodontics), conventional composite resin (Transbond XT, 3M Unitek), and color-changing composite resin (Transbond Plus, 3M Unitek) with conventional etch and self-etch primer (Transbond PlusSEP, 3M Unitek). Materials and Methods: Maxillary premolars (n=300) were bonded on the facial surface in five groups. The INSTRON machine was used for shear bond strength testing. Statistical Analysis: Comparison of the mean rank among the groups was done by Kruskal-Wallis one-way analysis of variance (ANOVA). To determine the mean difference among groups, the Mann-Whitney test with Bon Ferroni adjustment was applied. Observations: It was observed that light-cure conventional composite resin with the conventional etchant group had the highest and glass ionomer resin adhesive had the lowest shear bond strength. There was no statistically significant difference between conventional composite used with conventional etchant and color-changing composite resin used with conventional etchant or with self-etch primer. Conclusion: Considering the advantages of a color-changing composite and self-etch primer especially in patients having high DMFT scores or physically and mentally compromised patients unable to maintain their hygiene properly, it was concluded in the present study that it would be the most suitable material for direct bonding.