title: Vertical force and torque analysis during mechanical preparation of extracted teeth using hand ProTaper instruments.
abstract: The purpose was to measure and analyse the vertical force and torque developed in the wider and narrower root canals during hand ProTaper instrumentation. Twenty human incisors were divided in two groups. Upper incisors were experimental model for the wide, while the lower incisors for the narrow root canals. Measurements of the force and torque were done by a device constructed for this purpose. Differences between the groups were statistically analysed by Mann-Whitney U-test with the significance level set to P<0.05. Vertical force in the upper incisors ranged 0.25-2.58 N, while in the lower incisors 0.38-6.94 N. Measured torque in the upper incisors ranged 0.53-12.03 Nmm, while in the lower incisor ranged 0.94-10.0 Nmm. Vertical force and torque were higher in the root canals of smaller diameter. The increase in the contact surface results in increase of the vertical force and torque as well in both narrower and wider root canals.
authors.affiliation: Department of Dental Pathology, School of Dentistry, Medical Faculty, University of Rijeka, Rijeka, Croatia. snjezana_glavicic@yahoo.com
authors.forename: Snježana
authors.initials: S
authors.lastname: Glavičić
authors.forename: Ivica
authors.initials: I
authors.lastname: Anić
authors.forename: Alen
authors.initials: A
authors.lastname: Braut
authors.forename: Ivana
authors.initials: I
authors.lastname: Miletić
authors.forename: Josipa
authors.initials: J
authors.lastname: Borčić
mesh_terms: D003722:Dental Alloys / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D004867:Equipment Design; D006801:Humans; D007180:Incisor / Q000033:anatomy & histology; D008422:Materials Testing; D009532:Nickel / Q000737:chemistry; D009811:Odontometry / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation* / Q000379:methods; D013314:Stress, Mechanical; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000033:anatomy & histology; D014092:Tooth Root / Q000033:anatomy & histology; D019415:Torque
chemical_list: D003722:Dental Alloys; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium