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dc.contributor.authorWalter, Andre
dc.contributor.authorWinsauer, H
dc.contributor.authorMojal, Sergi
dc.contributor.authorMarcé Nogué, Jordi
dc.contributor.authorPuigdollers Pérez, Andreu
dc.contributor.otherUniversitat Politècnica de Catalunya. Departament de Resistència de Materials i Estructures a l'Enginyeria
dc.identifier.citationWalter, A. [et al.]. Design characteristics, primary stability and risk of fracture of orthodontic mini-implants: pilot scan electron microscope and mechanical studies. "Medicina oral, patología oral y cirugia bucal", Setembre 2013, vol. 18, núm. 5, p. e804-e810.
dc.description.abstractObjective: Orthodontic mini-implants (OMIs) are increasingly used in orthodontics but can fail for various reasons. This study investigates the effects of OMI design characteristics on the mechanical properties in artificial bone. Material and Methods: Twelve self-drilling OMIs (2 small, 6 medium, 4 large) from 8 manufacturers were tested for their primary stability in simulated medium-high cancellous bone and the risk to fracture in high-density methacrylate blocks. For the assessments of the maximum insertion torque (IT) and torsional fracture (TF) 5 of each OMI were used and for the pull-out strength (POS) 10. The OMIs were inserted with a torque screwdriver (12 sec/360°) until the bottom at 8 mm depth was reached. OMI designs were analyzed with a scan electron microscope (SEM). Results: SEM images revealed a great variation in product refinement. In the whole sample, a cylindrical OMI shape was associated with higher POS (p<0.001) but lower IT (p=0.002) values. The outer and inner OMI diameters were design characteristics well correlated with POS, IT and TF values (ranging from 0.601 to 0.961). Greater thread depth was related to greater POS values (r= 0.628), although OMIs with similar POS values may have different IT values. Thread depth and pitch had some impact on POS. TF depended mainly on the OMI inner (r= 0.961) and outer diameters (r=0.892). A thread depth to outer diameter ratio close to 40% increased TF risk. Conclusion: Although at the same insertion depth the OMI outer and inner diameters are the most important factors for primary stability, other OMI design characteristics (cylindrical vs. conical, thread design) may significantly affect primary stability and torsional fracture. This needs to be considered when selecting the appropriate OMI for the desired orthodontic procedures.
dc.subjectÀrees temàtiques de la UPC::Enginyeria dels materials::Desgast de materials
dc.subject.lcshImplants, Artificial
dc.subject.lcshFracture mechanics
dc.subject.otherorthodontic mini-implants
dc.subject.otherprimary stability
dc.subject.otherinsertion torque
dc.subject.otherpullout strength
dc.subject.othertorsional fracture
dc.titleDesign characteristics, primary stability and risk of fracture of orthodontic mini-implants: Pilot scan electron microscope and mechanical studies
dc.subject.lemacImplants artificials
dc.subject.lemacMecànica de fractura
dc.contributor.groupUniversitat Politècnica de Catalunya. LITEM - Laboratori per a la Innovació Tecnològica d'Estructures i Materials
dc.description.peerreviewedPeer Reviewed
dc.rights.accessRestricted access - publisher's policy
dc.description.versionPostprint (published version)
local.citation.authorWalter, A.; Winsauer, H.; Mojal, S.; Marcé-Nogué, J.; Puigdollers, A.
local.citation.publicationNameMedicina oral, patología oral y cirugia bucal

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