ABSTRACT
Objectives: The purpose of the present research was to demonstrate images of failure into the structure of nano composites using optical coherence tomography. Methods: Ten human third mandibular molars were taken in the study. A class V cavity was prepared and restored with nano composite universal. 20 OCT images of each tooth were obtained and a total of 200 images were evaluated after restoration. Spectral domain (SD-OCT), at 840 nm and a measured spatial resolution of 10 µm was used for the study, which is based on the Michelson interferometer set-up and is controlled by the software OCT 800 – Complex Square/LabView, that collects data and generates the image. The restored surfaces were scanned in a bucco-lingual direction and tomographic images were obtained. Later, the crown of each tooth was sectioned in a occlusogingival direction (buccolingually) and images of each section were obtained by a Stereo microscope. Images of OCT and stereo microscope were compared and evaluated. Results: Images obtained by OCT helped in identifying failures at surface and in the internal structure of composites. Significance: Images obtained from OCT helps in detecting the failures, gaps, bubbles which adversely effect the longevity of restoration.
ABSTRACT
Aim: The purpose of this study was to evaluate the influence of ultrasonic activation at different levels of endodontic therapy on filling quality of various sealers. Materials and Methods: Sixty extracted human single rooted teeth were divided into 4 groups (n=15) based on the sealer used to obturate the root canal instrumented up to F4 pro taper. These groups were subsequently divided into 3 sub-groups (n=5) each depending on the activation protocol followed in the study (i.e., no activation of irrigant /sealer, activation of final irrigant, activation of both irrigant and sealer). All samples were sectioned at 2, 4, 6 mm from apex. The percentage of sealer penetration of root canals were analysed. Results: In the groups where the final irrigant and sealer was ultrasonically agitated showed statistically significant increase in sealer penetration when compared to other groups. I Root SP (D) showed a statistically significant difference in sealer penetration when compared to ZOE, AH plus and HRS. Conclusion: The tubular penetration depth varies with the different physical and chemical properties of the sealers used. The use of ultrasonic activation at different levels of endodontic therapy facilitated better dentinal sealer penetration with I Root SP and AH Plus. I Root SP has solely satisfied and surpassed the test of better sealer penetration even at the apical level.
ABSTRACT
PURPOSE: Numerous methods were used to etch the fiber posts to improve its bonding to root canal dentin. Our aim was to evaluate the efficacy of 37% phosphoric acid in etching fiber posts in comparison with 24% hydrogen peroxide. MATERIALS AND METHODS: Ninety human maxillary central incisors were taken and post space preparation was done. Ninety fiber posts were taken and divided into three groups (n=30) based on the surface treatment they received (H3PO4, H2O2, distilled water) and each group was further divided (n=10) based on the time period of application (15 seconds, 30 seconds, 60 seconds). All the posts were luted into canals using Rely X UniCem-2. Each tooth was then sectioned into six slices and subjected to push out test. Data obtained was subjected to statistical analysis at P<.05. The surface topography was evaluated using scanning electron microscopy. RESULTS: Highest bond strength values were noted in 15 seconds etched phosphoric acid group and 60 seconds etched hydrogen peroxide group with no significant difference between two groups. Surface topography revealed complete epoxy layer removal with no damage to its structural integrity in those groups. CONCLUSION: H3PO4 etching for a period of 15 seconds is an effective alternative in improving the adhesion of fiber post to root dentin.