Retreatability of Bioceramic Endodontic Sealers: a Review.

In 2009 a new type of endodontic sealers was introduced to the market. The so called "bioceramic" sealers are a promising alternative to the present golden standard of root canal fillings. Now a decade later, still very little is known about the ability to remove these sealers in cases of non-surgical endodontic retreatment (NSER). There are only a limited number of articles that provide such information. The commonly used hand files are not efficient in removing thoroughly the sealer from the main canal walls. Machine driven files are much easier and faster alternative to the hand ones, but are still not able to ensure complete removal. Although ultrasonics can be applied only in the straight portion of the main canal, they raise the efficacy of sealer removal. Photon-initiated photoacoustic streaming (PIPS) is another way to enhance the removal of bioceramics. Solvents like chloroform and orange oil are effective in softening gutta-percha, but not the bioceramics. This article reviews the available scientific data concerning removal of bioceramic materials in the context of a NSER.

A Five-year Comparative Study of Perceived Stress Among Dental Students at Two European Faculties.

AIM: To compare the levels, causes and the impact of stress from cohort of fifthyear dental students in the Faculties of Dental Medicine in Plovdiv, Bulgaria and Montpellier, France. MATERIALS AND METHODS: The questionnaire we used comprised the modified version of the 56-item Dental Environment Stress (DES) questionnaire. It was completed by fifth-year undergraduate dental students in both faculties in 2011 and 2016, totaling 335 dental students. A five-point Likert scale was used to record the responses from the subjects. Statistical analysis was performed with STATA version 14.1 (StataCorp, College Station, USA) specialized software. RESULTS: The mean age of studied population was not significantly different between 2011 and 2016 (p=0.08). The common stress value per student was 1.74 (CI: 1.64; 1.84, range: 0.12; 4.50). It was higher in Plovdiv (1.79±0.81) than in Montpellier (1.63±0.66); it was statistically higher for girls (1.94±0.70) than for boys (1.49±0.77), and decreased between 2011 and 2016. A significant overall effect of the common mean stress was influenced by the town (p=0.008), year of study (p=0.003), gender (p=0.0001) and accommodation (p=0.01) of the student. CONCLUSION: Academicals and clinical factors of stress are prevailing stressors during education. The challenge is now to decrease the influence of both, without altering the quality of dental education. Regular discussions and debriefs about the clinical cases before and after clinical activity. Alternative methods of education and examination, such as interactive methods, could be considered in order to reduce the stress of theoretical exams.

Morphological Study Of Border Area Of Pulp-Capping Materials And Er:YAG Laser Prepared Hard Dental Surface.

INTRODUCTION: Vital pulp therapy involves biologically based therapeutic activities aimed at restoring health and preserving the vitality of cariously or traumatically damaged pulp. Adaptation of pulp-capping materials to the prepared tooth surface may be the key to the success of biological tooth treatment. AIM: To investigate the area of adaptation of synthetic tricalcium silicate cement, calcium hydroxide cement and mineral trioxide-aggregate to the dentin surface, prepared with the help of Er:YAG dental laser. MATERIAL AND METHODS: Four extracted human tooth cavities were prepared with the help of Er:YAG dental laser (LiteTouch, Syneron, Israel), establishing microcommunication with the pulp chamber less than 1 mm in diameter. As pulp-capping materials in the cavities we used tricalcium silicate cement (Biodentine, Septodont, France), calcium hydroxide cement (Dycal) and mineral-trioxide aggregate (ProRoot MTA), stirred and administered according to manufacturers' instructions. The first material fills the whole cavity and the other two are spread in a thin layer and sealed with glass ionomer cement. Thus prepared, the samples were left for three days at 37°C in humidified environment. The samples were prepared for scanning electron microscopy (SEM) by standard methodology. The border area surfaces of the materials and the dentin were scanned using electron microscopy. RESULTS: The morphological changes occurring to the Er:YAG laser prepared dentin and the structural characteristics of the studied pulp-capping materials are demonstrated using scanograms. The border areas where good contact of materials and dentinal tubules is established are thoroughly studied. Good adaptation is seen in three-calcium silicate cement, followed by mineral trioxide aggregate and calcium hydroxide cement. CONCLUSION: The dentin surface, prepared with Er:YAG laser demonstrates a very good adaptation of the three tested pulp-capping materials.