reflects the bacterial adhesion and plaque formation on the surface of tooth. This study basically intends to compare the remineralizing potential of the dentifrices containing recently invented CPP-ACP and β-TCP on dental erosion produced by soft drinks on enamel using AFM. Materials and Methods A total of 40 extracted human anterior teeth were collected for the study. Teeth were cleaned by ultrasonic scaler to remove soft debris and inspected for cracks, hypoplasia or any white spot lesions. Further disinfection was carried out by immersing them in 5% sodium hypochlorite for 1 hour and storing in de-ionized water. The specimens were decoronated and sliced longitudinally for the labial portion using diamond disc with water irrigation. The labial surface of each enamel specimen grounded using silicon carbide papers with consecutive 600, 1000 and 1200 grits under water irrigation for producing a flat surface. The CPP-ACP paste used was GC Tooth mousse (GC Corp, Tokyo, Japan) and β-TCP paste was Clinpro TM Tooth Crèam (3M ESPE, USA) (Figure 1). The pH of soft drink was determined by pH meter. All the samples were randomly divided into two groups. Group

A BSTRACT Background: Periapical lesions can be appreciated in the teeth that have underwent root canal treatment leading to more complications. Radiographic as well as histological evaluation is important for definitive diagnosis. Aim: The aim of this study was to examine the histology of constant periapical radiolucent lesions that are associated with root canal treated teeth and also to find association between histological findings and radiographic size of lesion as well as existence or nonappearance of a radiopaque lamina. Materials and Methods: The study included 60 incisors and canines allotted for apical microsurgery. Two observers studied the diameter of periapical radiolucent lesions and the existence or nonappearance of radiopaque lamina. During apical microsurgery, biopsy specimens were collected and after tissue processing oral pathologist examined the specimen under a light microscope. Histological features of the specimen were taken into consideration, and the diagnosis of abscess, cyst, granuloma, and scar tissue were given. Pearson’s chi-square test was used to study the established relationship between histological diagnosis and lesion size. Results: Results indicated that 68.33% of lesions were granulomas, 23.33% were cysts, 5% were abscesses, and 3.33% were scar tissue. Conclusion: According to histological results, most of the lesions in this study were granulomas, followed by cysts. Abscesses and scar tissues were rare.