Thesis (M.Sc.) - Cairo University - Faculty of Oral and Dental Medicine - Department of Operative Dentistry

Objectives: to evaluate the microhardness of incipient enamel-like lesions with or without pre-conditioning by air-abrasion using polyacrylic acid-bioactive glass before application of NovaMinremineralizing agent. Methods: Forty extracted human molars were selected , sectioned mesiodistally obtaining buccal and lingual halves and embedded in resin molds allowing each specimen to serve its own control. Specimens were randomly assigned to 4 groups (n=10) according to the remineralization protocol: G1- (Control, artificial saliva), G2- (pre-conditioning), G3- (NovaMin), G4- (pre-conditioning and NovaMin). Enamel windows 4mmx4mm were done on the buccal and lingual surfaces. Specimens were immersed in a daily renewed demineralizing solution to create artificial white spot lesions. Remineralizing agents were applied according to the manufacturer{u2019}s instructions and specimens were stored in a daily renewed artificial saliva. Microhardness was assessed using Vicker's hardness number (VHN) at baseline (positive control), after demineralization (negative control), 24 hours and one month remineralization. Results: pre-conditioning / NovaMin group after one month showed a statistically significant high VHN, with no statistically significant difference between it and the positive control. This was followed by NovaMin group after one month, while the lowest VHN was found in the demineralized group with no statistically significant difference between it and the pre-conditioning group, whether after 24 hours or one month

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