The effect of root canal rinsing protocol on the push-out bond strength to the dentin cementation of the fiber post.

B a c k g r o u n d: Studies on the effect of root canal rinsing protocols on fiber post bonding to dentin are inconclusive. This study reports investigation of this topic. O b j e c t i v e s: to determine effects of irrigation protocol by means of a push-out test on the strength of adhesion between the post and dentin in an in vitro study. Materials and Method: Thirty human single-rooted teeth were prepared using hand instruments and the step-back technique, filled with gutta-percha, sealed with AH Plus (Dentsply), and divided into three groups: A: rinsed with NaCl; B: rinsed with 2% chlorhexidine (CHX); C: not rinsed before cementation of posts. The fiber posts were set using RelyX and Built-it. The tooth roots were sliced and the push-out test was performed. The area of contact between the post and dentin was calculated and the destroying force was established. The results were statistically analyzed. R e s u l t s: The mean adhesive strength was 10.69 MPa in group A, 16.33 MPa in group B, and 16.72 MPa in C. The adhesive strength in group B and C was statistically significantly higher than in group A (p = 0.0016, ANOVA). Conclusion: Rinsing root canals with CHX seems to be the most effective method prior to setting a fiber post.

The Evaluation of Anthropometric Measurements of Young Polish Women's Faces.

Face proportions are under constant evaluation during prosthetic or surgical diagnostics and treatment. The aim was to evaluate the proportions of the faces of young Polish women as compared with other ethnic groups. MATERIALS AND METHODS: The evaluation included 60 photographs of the faces of women, average age 17.9 years. En face images were made with the camera lens situated at the same distance from the photographed subjects. Using Adobe Photoshop software, midsaggital and even anthropometric points were determined in the photographs and then the distance between these points was measured. Four relationships between vertical measurements, 3 between horizontal measurements, and 4 proportions between vertical and horizontal measurements were calculated. The results were evaluated in comparison with the golden ratio (1.618) and the measurements performed for native Americans and Latin American beauty contests winners described in the relevant literature. RESULTS: The result for the average vertical face proportion value of the examined women was close to the golden ratio (GR) and amounted to 1.592 for the proportions between nasion-stomion and stomion-gnation (98% of GR) and 1.372 for nasion-subnasale and subnasale-gnation (85% of GR).Average measurement results for young Polish women's faces were not statistically significantly different for 6 out of 11 relationships under evaluation as compared with the population of native American females and only 2 face proportions were the same as for beauty contests winners from Latin America. CONCLUSION: Face proportions of young Polish women were different from those of the females living in the American continent.

The evaluation of the effect of carbon dioxide laser radiation on dentine tissue.

of this study was to analyze the effects of carbon dioxide (CO2) laser light on the structure and elemental composition of dentine. METHODS: The evaluation was conducted on samples from extracted teeth. The surface of the dentine was exposed to the radiation from a CTL 1401 CO2 laser (Centre of Laser Technology, Poland). The radiation and frequency parameters were as follows: group I with 5 W and 1 Hz, group II with 10 W and 1 Hz, group III with 5 W and 5 Hz, and group IV with 10 W and 5 Hz. The altered dentine structure was macroscopically and microscopically evaluated using a Nova NanoSEM 200 Scanning Electron Microscope (FEI Europe) with integrated microanalysis X-ray system for elemental analysis in points. RESULTS: There were significant differences between groups in the macro- and microstructure of laser defects. CONCLUSIONS: CO2 laser radiation causes irreversible, destructive changes in dentine. The structural dentine lesions developed under the influence of the CO2 laser radiation may hinder proper adhesion of bonding systems with the damaged tissue. Laser defects in the structure should be treated like defects of noncarious origin requiring preparation and filling with composite materials in accordance with the procedures.

The evaluation of the accuracy of shape imaging of prosthetic abutment.

PURPOSE: The aim of the study was the in vitro evaluation of the accuracy of shape imaging of abutment teeth using different impression compounds. METHODS: To compare the accuracy of the shape of the numerically imaged real prosthetic abutments with the tested models of abutments obtained with the replica technique, the Geomagic Qualify program was applied. Making use of the licensed program Statistica, statistical analysis of the results obtained was conducted. RESULTS: In the research procedures, analyses were conducted for 10 abutment premolars and 10 abutment molars. The tests allowed us to state that the dimensional accuracy of the models of prosthetic abutments obtained with the application of elastic compounds tested ensures comparable shape imaging. CONCLUSIONS: The objective method developed and applied here is suitable for controlling the imaging of the abutment teeth. The Geomagic Qualify program that was used during the research is a reliable tool of 3D analysis for the estimation of procedure of abutment tooth preparation and indication of an error of shape of prepared occlusal surface, lateral surface of abutment and errors of shaping the chamfer zone.

Microstructural and micromechanical tests of titanium biomaterials intended for prosthetic reconstructions.

PURPOSE: The aim of the present paper was a question of structural identification and evaluation of strength parameters of Titanium (Ticp - grade 2) and its alloy (Ti6Al4V) which are used to serve as a base for those permanent prosthetic supplements which are later manufactured employing CAD/CAM systems. METHODS: Microstructural tests of Ticp and Ti6Al4V were conducted using an optical microscope as well as a scanning microscope. Hardness was measured with the Vickers method. Micromechanical properties of samples: microhardness and Young's modulus value, were measured with the Oliver and Pharr method. RESULTS: Based on studies using optical microscopy it was observed that the Ticp from the milling technology had a single phase, granular microstructure. The Ti64 alloy had a two-phase, fine-grained microstructure with an acicular-lamellar character. The results of scanning tests show that titanium Ticp had a single phase structure. On its grain there was visible acicular martensite. The structure of the two phase Ti64 alloy consists of a ß matrix as well as released α phase deposits in the shape of extended needles. Micromechanical tests demonstrated that the alloy of Ti64 in both methods showed twice as high the microhardness as Ticp. In studies of Young's modulus of Ti64 alloy DMLS technology have lower value than titanium milling technology. CONCLUSIONS: According to the results obtained, the following conclusion has been drawn: when strength aspect is discussed, the DMLS method is a preferred one in manufacturing load structures in dentistry and may be an alternate way for the CAD/CAM system used in decrement processing.