Introduction: Feldspathic porcelains and zirconia crowns are the most applied DENTAL ceramic materials. Teeth wear against these ceramics has turned into a major concern. Primary surface roughness of these ceramics can have a significant impact on ENAMEL abrasion. This study aimed to detect an association between ENAMEL abrasion and surface roughness of DENTAL ceramics.Materials & Methods: In this laboratorial study, polished zirconia samples, polished feldspathic porcelains, and polished and glazed feldspathic porcelains were prepared (N=11). In addition, human natural premolar teeth were provided as antagonist. Afterwards, mounted tooth samples were photographed by a stereo microscope in a fixed position and the distance from the cusp tip to the reference point was measured. Surface roughness of all samples was evaluated before the test using a profilometer device. Following that, ceramic samples were tested against DENTAL samples. Moreover, 11 tooth samples (control group) were tested against another 11 tooth samples in chewing simulator device with 120000 masticatory cycles (equal to six months of chewing). Afterwards, tooth samples were photographed again and differences between the measurements were recorded. Data analysis was performed in SPSS version 20 using the kruskal-Wallis test and scatter diagram graphs, and P-value of less than 0.05 was considered statistically significant.Results: In this study, mean and standard deviation of surface roughness rate in polished porcelain, polished and glazed porcelain, polished zirconia ceramics and control group were 1.48±0.083, 1.20±0.126, 0.535±0.086 and 0.039±0.006 micrometers, respectively. According to the results, a statistically significant difference was observed between the level of surface roughness in the study groups (P<0.001). Among the ceramics, the highest levels of abrasion and surface roughness were observed in the polished porcelain group, whereas the lowest levels were allocated to the polished zirconia group.Conclusion: According to the results of this study, higher level of surface roughness of ceramics increased tooth abrasion.

The white spot lesion on the DENTAL ENAMEL is an optical alteration that compromises the esthetics of smile. It can be caused by many factors, among them, defects in mineralization and formation of tooth ENAMEL. Resin infiltrants are agents that penetrate, by capillarity, through the pores of the demineralized or hypomineralized ENAMEL, altering the refractive index (RI) of the tooth structure and totally or partially masking the appearance of the white spot. The aim of this work was to report the use of resin infiltration to minimize the visualization of white spot lesion, present in an upper central incisor, as a microinvasive approach for the esthetic treatment of deep ENAMEL hypomineralization. A 20‑, year‑, old female patient sought care with the esthetic complaint of extensive white spot lesion on the buccal face of her upper right central incisor. The diagnosis established was a deep white stain associated with the incisor molar hypomineralization syndrome, and the treatment of choice for the resolution of the case was the application of the Icon®,resin infiltrant (DMG, Hamburg, Germany). To reach the body of the lesion, three cycles of acid erosion, using 15% HCl, were necessary to obtain a satisfactory aspect of masking the white lesion. A camouflage effect of the deep white spot lesion was achieved with the use of the resin infiltration, without the need of additional and irreversible wear of the DENTAL structure.

FT-Raman Spectra of human DENTAL ENAMEL, both Laser-irradiated and untreated, are reported. Spectra are compared with hydroxyapatite. It is evident that unlike the CO2 laser, the Nd/YAG laser does not induce any chemical change in DENTAL ENAMEL.

Introduction: The increasing trend of research concerning bonds between Metal, porcelain, … and DENTAL tissue of ENAMEL and dentine, to determine which bonding agent has a higher quality in particular conditions has been going on. Objective: This research was carried out to compare three types of bonding agents Panavia Ex, Mirage bond Flc and Optibond in shear bond strengths porcelain and tissue of ENAMEL. Materials and Methods: In 60 samples of human teeth which were divided in three groups of A, B and C (each group consisting of 20 samples) porcelain was bonded to ENAMEL with these three bonding agents, then they were put under the Instron machine with shear force of 0.5 cm/min On the porcelain near the bonding place. According to the separation time of porcelain from ENAMEL the bond strength power was obtained. Results: After calculating the average figures and variance analyzing (Anova) and also using Scheffe, Duncan, Tukey Hsd Test, these results with were reported in groups A, B and C respectively: Panavia Ex 4.39 Mpa, Mirage Bond Flc 10.41 Mpa and optibond with the most shear strength of 15.90 Mpa Conclusion: Regarding to the result of this research, optibond material was found to have a higher shear bond strength, comparing with the two other substances. Therefore it can be used to bond Inlay، Only and porcelain crown to the tissue of ENAMEL.

Background: Current diagnostic methods for ENAMEL caries detection are unable to detect caries lesions (incipient caries lesion) at a very early stage. Objective: This study aims to determine the remineralizing effect of three fluorinated compounds on demineralized subsurface tooth ENAMEL using Raman spectroscopy characterization. Material and Methods: In this experimental study, sixty impacted 3rd molars, with intact anatomical crowns recently extracted and without structural defects, were sectioned longitudinally in a mesio-distal direction using a diamond disc, obtaining two working surfaces (buccal and lingual). The 120 working surfaces obtained were immersed for 96 h in a demineralization solution at 37° C in order to demineralize the ENAMEL surface. All samples were randomly divided into three groups (n=30 each) and their surfaces were treated with silver diamine fluoride (SDF), Difluoride silane (DSF), and acidulated phosphate fluoride (APF), and with no treatment undertaken in the control group (CG). The samples were immersed in alternating solutions for demineralization and remineralization at pH 4. 4 and pH 7. 0, respectively. The results were analyzed with Principal Component Analysis (PCA) in order to determine the variance. Results: The most important difference (91. 7%) is observed in APF group between PCA1 respect to PCA2, followed by DSF (91. 5%) and SDF (76. 3%) respectively. Therefore, a greater remineralization in the DENTAL ENAMEL can be observed by the three experimental groups. Conclusion: The APF and DSF have the effect of recovering the mineralization of DENTAL ENAMEL, except for the SDF. Functional groups OH-and PO4 3-were identified in all subsurface.

Objectives: This study aimed to assess the effect of tea on color stability of ENAMEL lesions treated with resin infiltrant (RI). Materials and Methods: This in vitro, experimental study evaluated 30 extracted human third molars with no caries, cracks, or ENAMEL defects. ENAMEL-dentin samples measuring 5 x 5 x 3 mm were prepared from the buccal surfaces of the teeth by a microtome. The samples were divided into three groups of 10 namely sound ENAMEL, demineralized ENAMEL, and demineralized ENAMEL plus RI. White spot lesions (WSLs) were artificially created by immersing the samples in hydroxyethyl cellulose demineralizing gel with a pH of 4. 5 for 4 days. Next, Icon RI was applied on the samples in group 3. The baseline color of the samples was measured using a spectrophotometer. They were immersed in tea solution 3 times a day, each time for 15 min, for a period of 2 weeks and then underwent colorimetry again. Data were analyzed using one-way ANOVA. Results: The maximum color change (∆ E) was noted in demineralized ENAMEL plus RI group (38. 59± 6. 13) with significant differences with sound ENAMEL (20. 00± 2. 94) and demineralized ENAMEL (25. 27± 7. 47) groups (P<0. 05). The difference between the latter two groups was not significant (P>0. 05). Conclusion: Within the limitations of this in vitro study, the results showed that tea solution caused clinically unacceptable color change in all groups. However, the color stability of WSLs treated with RI was significantly lower than other groups following immersion in tea solution.