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Article
In vitro evaluation of sealing ability of matched-taper single cone obturation with an electrochemical method.

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Abstract

Abstractwidespread use of rotary Nickel-Titanium systems has caused manufacturers toproduce gutta-percha cones that match the taper of the canals prepared with thesesystems. The aim of this study was to use electrochemical method to compare theapical sealing ability of taper single-cone, Thermafil obturation in canals preparedwith ProTaper and ProFile instruments. Forty extracted human mandibular premolarwere divided into 2 groups. All canals in group (A) prepared with ProFile, while allcanals in group (B) prepared with ProTaper. Each group subdivided into twosubgroup according to the method of obturation, (Thermafil and matched taper- singlecone).The apical leakage in these groups was evaluated using an electrochemicalmethod. T-test showed a non significant difference between Thermafil and matchedtaper-single cone obturation technique in the same group. A significant difference wasfound between ProTaper and ProFile group in both obturation techniques.


Article
The effect of Hand Stainless-Steel and NiTi Rotary file on vertical root fracture.

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Abstract

The aim of this study was to compare the fracture resistance of roots followingroot canal therapy using stainless-steel hand instrumentation (SS), Rotary Profile (PF)instrumentation, Rotary ProTaper instrumentation (PT). Forty-five mandibularpremolars teeth were divided into three groups of 15 teeth each, according to the typeof instrumentation. All root obturated with gutta-percha and AH26 sealer. The rootswere vertically loaded using a universal testing machine. Fracture loads were analysedby ANOVA and LSD test, and fracture patterns were analyzed with Chi-Square.Profile & ProTaper groups have significantly lower fracture load than handinstruments group (P < 0.05). Chi-Square showed a significant differences betweengroups (P < 0.05) .


Article
A comparison of apical microleakage after lateral condensation of different tapered master cone in canals prepared by ProFile rotary instruments

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Abstract

Forty five mesial canals of extracted human mandibular molars were instrumentedwith ProFile ISO .06 nickel-titanium rotary instruments and obturated with lateralcondensation using three different master cones: .06 tapered gutta-percha cone (groupI), .04 tapered gutta-percha cone (group II), .02 tapered gutta-percha cone (group III).Zinc oxide eugenol sealer was used in all groups. After 48 hours in an incubator, theroots were coated with nail polish and were the submerged in methylene blue dye for72 hours. The roots were then split longitudinally and the apical leakage measuredand compared for each group. Although there was no statistical significant differenceamong groups (P>0.05), group (I) with .06 tapered gutta-percha master cone showedthe lowest mean of dye penetration.


Article
Urinary Mercury concentrations associated chewing gum in students of Faculty of Dentistry

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Abstract

The aim of this study was to measure the urinary mercury concentration instudents after chewing gum for certain period of time. Sixteen students from facultyof dentistry had used chewing gum for five hours a day for seven days. Urine samplecollected 24 h before and after the experimental time. Total mercury in urine (U-Hg)was determined by means of inductively coupled plasma mass spectrometry (ICPMS).t-test was used for the comparison of mercury before and after chewing gum. Anon significant difference was found after chewing than before chewing gum.

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