RESUMO
BACKGROUND: The aim of this study is to compare the torsional resistance of the available ProTaper rotary systems, namely, ProTaper Universal (PTU), ProTaper Next (PTN), and ProTaper Gold (PTG). METHODS: A total of 195 files from the three systems distributed into 13 groups (PTU-S1, PTU-S2, PTU-F1, PTU-F2, PTU-F3, PTG-S1, PTG-S2, PTG-F1, PTG-F2, PTG-F3, PTN-X1, PTN-X2 and PTN-X3) were subjected to torsional fatigue until failure. The torsional test was performed according to ISO 3630-1, where each file was placed in a straight position to eliminate the influence of cyclic fatigue. The Kruskal-Wallis test was conducted to compare the mean maximum torques and angular deflections at fracture for the groups, and the Mann-Whitney test was performed for pairwise comparisons. The significance level was set at 0.05 and the fractured surfaces were examined under a scanning electron microscope. RESULT: Among the tested files, PTG-S1 had the lowest torsional fatigue resistance, whereas PTU-F2 and PTU-F3 had the highest torsional resistance. The scanning electron microscope showed typical features of torsional failure. CONCLUSION: The new ProTaper systems (PTG and PTN) did not show improved torsional resistance in comparison with PTU.
Assuntos
Teste de Materiais , Preparo de Canal Radicular/instrumentação , Falha de Equipamento , Humanos , Microscopia Eletrônica de Varredura , Níquel , TitânioRESUMO
The surgeon's aesthetic analysis of the nose is based on scientific measures of its proportions and dimensions. Because the primary aim of rhinoplasty is targeted at the patient's satisfaction with self-image, patients' perception and satisfaction are of paramount importance. The aim of this study was to evaluate surgeon versus patient nasal aesthetic analysis. Method: A cross-sectional study was conducted on 57 primary rhinoplasty consultations during the period June and September 2017 at the Plastic Surgery Clinic in King Fahad Hospital-Hofuf. The surgeon and the patients were handed identical questionnaires before the consultations. The questionnaire has 27 components regarding the nasal appearance. Results: The surgeon's and the patients' perceptions regarding reliability was assessed by Cohen's Kappa and Pearson's correlation coefficient. There was moderate agreement with the overall appearance of the nose (κ = 0.2-0.39). The most agreed-upon components were "dorsal hump" (κ = 0.6, P = 0.001) and "tip drops down" (κ = 0.41, P = 0.002). The columella and the suitability of the front part of the nose had the largest disagreement (κ = -0.06 and κ = -0.09, respectively). The level of agreement among most of the questionnaires' components was slight or nonexistent (κ = 0.004-0.39). Conclusions: The surgeon and patients have a minimum agreement regarding the view of nasal appearance, mostly with the suitability of the front part and the columella. The parts of the nose agreed upon the most were "dorsal hump" and "tip drops down". Exploring the differences between patient and surgeon aesthetic analysis of the nose will aid in addressing the discrepancies and improving surgical outcome and satisfaction.