CHEMICAL AND MORPHOLOGICAL ANALYSIS OF HUMAN DEMINERALIZED ENAMEL SURFACE BY ACID AND LASER ETCHING FOLLOWING REMINERALIZATION BY MI PASTE PLUS

Objectives: The aim of the present study was to evaluate the effects of remineralizing agent (MI Paste Plus) on the surface topography and chemical analysis of sound human enamel following acid-etching and laser etching, using Environmental scanning electron microscopic (ESEM) techniques.
Materials and Methods: Fifty human upper premolars extracted for orthodontic reason were used. The teeth were mounted vertically in a self-cure acrylic cylinder. One clinician prepared all the teeth, in each tooth; a 4x4 mm area was treated in middle third of the buccal surface. The teeth were divided into three groups, Group I : Control group no treatment ; Group II: enamel etched with 37% phosphoric acid; Group III: enamel was irradiated with Er,Cr:YSGG laser. Group II and III were subdivided into subgroup according to remineralizing agent (GC MI Paste Plus), (n=10). Remineralizing paste was used as manufacturer’s instructions, a single application of approximately 0.5 mm layer for 3 minutes; twice daily. Synthetic saliva was rinsing between remineralizing paste application, followed by synthetic saliva rinsing for 15 days with fresh replenished on a daily basis. Teeth were examined for morphological and chemical characterization using an Environmental Scanning Electron Microscope. All of the data were analyzed by two-way analysis of variance (ANOVA) and Tukey’s post hoc test.
Results: Morphological changes of enamel surfaces of acid-etching group showed type 1 etching pattern and laser etching group showed the normal appearance of the enamel prisms (honeycomb-like structure). Comparison of all groups and control group P & Ca weight%, the greatest mean value was recorded in acid etch group before and after remineralization with GC MI Paste Plus.
Conclusion: Within the limits of this in vitro study, Since Ca and P constitute the major part of tooth structure, while other element represent trace element; results emphasize the effect of GC MI Paste Plus on tooth remineralization. Comparison of all groups and control group, acid etch group before and after remineralization recorded the greatest mean value for P & Ca weight%. Laser etching didn’t have a significant effect on tooth composition and mineral content.