Torsional properties and microstructures of miniscrew implants

Iijima, Masahiro; Muguruma, Takeshi; Brantley, William A.; Okayama, Miki; Yuasa, Toshihiro; Mizoguchi, Itaru

doi:10.1016/j.ajodo.2008.03.012

Cited by 33 publications

(33 citation statements)

References 20 publications

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“…7,16,17 (Table I) An alpha alloy will basically comprise of titanium that is commercially pure titanium with alpha stabilizing elements added such as aluminum, nitrogen, and oxygen. 18,21 Addition of aluminum to titanium increases the tensile strength, creep strength and elastics modulus and also will expand the  phase and increase the strength. 19,20 The mechanical properties of alpha titanium can be altered using different cooling rates after annealing at temperatures higher than that required for alpha to beta phase transformation.…”

Section: Titanium and Its Alloysmentioning

confidence: 99%

“…Alpha (α) alloys essentially have an all-alpha microstructure and no  phase on cooling. 18,19,20,21 Chemical composition, % max of commercially pure titanium. 7,16,17 (Table I) An alpha alloy will basically comprise of titanium that is commercially pure titanium with alpha stabilizing elements added such as aluminum, nitrogen, and oxygen.…”

Section: Titanium and Its Alloysmentioning

confidence: 99%

“…Typically, fatigue strength is less than 50% of the ultimate tensile strength (UTS) 7,18 The results showed miniscrew A and C implants were pure titanium (equiaxed alpha titanium), whereas B and D contains small globular particles of beta titanium in a matrix of alpha titanium, Only α-titanium peaks were detected for all implants by micro x-ray diffraction, but beta-titanium was observed in the microstructures of B and D implants, which had significantly higher torsional moments at failure. 21 Yokoyama et al opined that alpha titanium in the biological environment absorbs hydrogen and this may be the reason for delayed fracture of the titanium implants owing to the formation of Titanium hydride, over a period of time in the presence of moisture. 22,17 Compared with Co-Cr-Mo alloys, titanium alloys is almost twice as strong and has half the elastic modulus.…”

mentioning

confidence: 99%

“…23 Sufficient mechanical strength is needed for implants used in orthodontics to resist torsional stresses developed at the screw threads during clinical placement and removal. 21 The forces associated with placement and removal can cause miniscrew failure, especially if partial integration has occurred. For this reason, in more mineralized tissue, the tension applied on rotation may reach their breaking point.…”

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confidence: 99%

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Mini- Implant Materials: An Overview

Sana¹

2013

IOSR-JDMS

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Section: Titanium and Its Alloysmentioning

confidence: 99%

Section: Titanium and Its Alloysmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Mini- Implant Materials: An Overview

Sana¹

2013

IOSR-JDMS

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“…Higher insertion torque values reduce the risk of implant micromovements at the bone-implant interface, thereby obtaining higher rates of success of immediately loaded implants (6,7). On the other hand, implants can undergo morphological changes during torsion when inserted into bone (8). These changes, associated with the masticatory load, may affect the rotational freedom between implant and abutment and, hence, affect the implant/abutment stability (9-11).…”

Section: Introductionmentioning

confidence: 99%

External Hexagon Deformation in Implants Subjected to Internal Torque

Magalhães

Naves

Menezes³

et al. 2015

Braz. Dent. J.

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Failures may occur in the connections of dental implants, especially in external hexagon (EH). Due to the deformations in this portion of implants, this study aimed to evaluate the levels of deformation of EH connections subjected to internal toque. Two types of implants were used: N group and S group. Torques of 0, 32, 45, 60 and 80 Ncm were applied to the N group, and torques of 0, 30, 40, 60 and infinite Ncm were applied to the S group implants. The internal distance (ID), internal area (IA) and external area (EA) of the EH were obtained from digital pictures, which were analyzed by a specific software. Statistical analysis was performed by the Scott-Knott test. The results showed that the higher the torque applied, the greater were the changes in the evaluated dimensions in both groups. In the S group, torque levels equal or greater than 40 Ncm and 30 Ncm caused greater deformation of EA and IA respectively, while in the N group, torque levels equal or greater than 60 Ncm and 32 Ncm caused greater deformation of EA and IA respectively. Levels of deformation were greater in the S group as compared with the N group. These findings suggest that the IA, EA and ID of the EH may be affected by different internal torque levels.

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Effectiveness of methods for detaching orthodontic implants likely to fracture upon rotational torque – an animal study

Nakagaki

Iijima

Yasuda³

et al. 2016

Clinical & Exp Dental Res

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Orthodontic implants may fracture at the cortical bone level upon rotational torque. The impacted fragment can be detached by a range of methods, which are all more or less time‐consuming and injurious to the cortical bone. The aim of this study was to compare three different methods for detaching an orthodontic implant impacted in cortical bone. Health Sciences University of Hokkaido animal ethics committee approved the study protocol. Orthodontic titanium‐alloy (Ti‐6Al‐4 V) implants were placed bilaterally on the buccal side of the mandible of beagle dogs. Subsequently, the implants were detached using either a low‐speed handpiece with a round bur, alternatively by use of a low‐power or a high‐power ultrasonic instrument. In the first experiment, 56 orthodontic implants were placed into the dissected mandible from 7 animals. The methods for detachment were compared with respect to time interval, as well as associated undesirable bone loss as appraised by use of cone‐beam computed tomography. In experiment two, 2x2 implants were placed bilaterally in the mandible of 8 animals and subsequently detached by manual rotational torque, and the described three methods for detachment. The implant socket was investigated histologically as a function of removal method immediately after removal, and after 1, 3 and 8 weeks and contrasted with the healing of the socket of the implant that was detached by manual rotational torque. Statistical significance was appraised by the use of non‐parametric Kruskal‐Wallis one‐way analysis of variance. The method using the low‐power ultrasonic required significantly longer removal time versus the two other methods, i.e. high‐power ultrasonic and low‐speed handpiece with a round bur (p < 0.02). The amount of undesirable bone loss was substantially larger with low‐speed handpiece with a round bur compared to the two ultrasonic methods (p < 0.05). Bone formation after 3 weeks of healing was more complete following the use of low or high‐power ultrasonic instrument in comparison with a low‐speed handpiece rotary instrument method. Orthodontic implants likely to fracture upon rotational torque or impacted fractured fragments should be detached preferably with an ultrasonic instrument, because of less associated bone loss and more rapid bone healing compared to the use of a low‐speed handpiece rotary instrument.

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Torsional properties and microstructures of miniscrew implants

Cited by 33 publications

References 20 publications

Mini- Implant Materials: An Overview

Mini- Implant Materials: An Overview

External Hexagon Deformation in Implants Subjected to Internal Torque

Effectiveness of methods for detaching orthodontic implants likely to fracture upon rotational torque – an animal study

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