Microdamage in Cortical Bone due to the Overtightening of Orthodontic Microscrews

Wawrzinek, Christian; Sommer, Thorsten; Fischer-Brandies, H

doi:10.1007/s00056-008-0742-5

Cited by 73 publications

(52 citation statements)

References 34 publications

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“…4,20,21,22 During exploration of this bone, it was observed that some characteristics such as color, texture and drill resistance differed in its various regions. Pubic bone was darker and more resistant when compared with iliac bone.…”

Section: Discussionmentioning

confidence: 99%

Is miniscrew primary stability influenced by bone density?

et al. 2011

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Primary stability is absence of mobility in the bone bed after mini-implant placement and depends on bone quality among other factors. Bone quality is a subjective term frequently considered as bone density. The aim of this preliminary study was to evaluate bone density in two bovine pelvic regions and verify the primary stability of miniscrews inserted into them. Forty bone blocks were extracted from bovine pelvic bones, 20 from iliac and 20 from pubic bone, all of them containing cortical bone about 1 mm thick. Half of the sections extracted from each bone were designated for histological evaluation of bone density (trabecular bone area -TBA) and the other half for bone mineral density (BMD) evaluation by means of central dual-energy X-ray absorptiometry (DEXA). Then, twenty self-drilling miniscrews (INP  , São Paulo, Brazil) 1.4 mm in diameter and 6 mm long were inserted into the bone blocks used for BMD evaluation. Peak implant insertion torque (IT) and pullout strength (PS) were used for primary stability evaluation. It was found that iliac and pubic bones present different bone densities, iliac bone being less dense considering BMD and TBA values (P > 0.05). However, the miniscrew primary stability was not different when varying the bone type (P < 0.05). IT and PS were not influenced by these differences in bone density when cortical thickness was about 1 mm thick.

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Section: Discussionmentioning

confidence: 99%

Is miniscrew primary stability influenced by bone density?

et al. 2011

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“…values may result in higher failure rates due to a distinctive bone compression with microdamages 24 or even to mini-implant fracture at torque moments above 200 Nmm. 18 As a consequence, it seems important to adapt the clinical procedure to the local circumstances (bone quality, thickness of the gingiva, available space) and the insertion procedure (transgingival vs submucosal insertion).…”

Section: Discussionmentioning

confidence: 99%

“…18 For mini-implants with a diameter of 1.6 mm, an insertion torque of 5 Ncm to 10 Ncm (50 Nmm to 100 Nmm) seems to be favorable to minimize the risk of failure. 12,13 Higher values may result in higher failure rates because of a distinctive bone compression with microdamages 24 or may even cause mini-implant fracture. 18 To summarize, it seems very important (1) to know the factors affecting the insertion torque/primary stability exactly and (2) to adapt the clinical procedure with the goal of achieving an insertion torque in the recommended range.…”

Section: Introductionmentioning

confidence: 99%

Impact of Insertion Depth and Predrilling Diameter on Primary Stability of Orthodontic Mini-implants

Wilmes

Drescher

2009

The Angle Orthodontist

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Objective: To test the hypothesis that the impact of the insertion depth and predrilling diameter have no effect on the primary stability of mini-implants. Materials and Methods: Twelve ilium bone segments of pigs were embedded in resin. After implant site preparation with different predrilling diameters (1.0, 1.1, 1.2, and 1.3 mm), Dual Top Screws 1.6 ϫ 10 mm (Jeil, Korea) were inserted with three different insertion depths (7.5, 8.5, and 9.5 mm). The insertion torque was recorded to assess primary stability. In each bone, five Dual Top Screws were used as a reference to compensate for the differences of local bone quality. Results: Both insertion depth and predrilling diameter influenced the measured insertion torques distinctively: the mean insertion torque for the insertion depth of 7.5 mm was 51.62 Nmm (Ϯ25.22); for insertion depth of 8.5 mm, 65.53 Nmm (Ϯ29.99); and for the insertion depth of 9.5 mm, 94.38 Nmm (Ϯ27.61). The mean insertion torque employing the predrill 1.0 mm was 83.50 Nmm (Ϯ33.56); for predrill 1.1 mm, 77.50 Nmm (Ϯ27.54); for the predrill 1.2 mm, 61.70 Nmm (Ϯ28.46); and for the predrill 1.3 mm, 53.10 (Ϯ32.18). All differences were highly statistically significant (P Ͻ .001). Conclusions:The hypothesis is rejected. Higher insertion depths result in higher insertion torques and thus primary stability. Larger predrilling diameters result in lower insertion torques. (Angle Orthod. 2009;79:609-614.)

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“…11 While some recommend 5-10 Ncm insertion torques, 12 in general, higher insertion torque would produce greater primary stability. 13,14 But, excessive insertion torque produces potential failure due to bone necrosis, 15 microdamage, 16,17 or MSI fracture during insertion. 18 To avoid excessive insertion torque, one approach is to change the shape of the MSI.…”

Section: Introductionmentioning

confidence: 99%

Microdamage generation by tapered and cylindrical mini-screw implants after pilot drilling

Taing-Watson

Katona

Stewart

et al. 2014

The Angle Orthodontist

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Objective: To investigate the relationship between mini-screw implant (MSI) diameter (1.6 vs 2.0 mm) and shape (tapered vs cylindrical) and the amount of microdamage generated during insertion. Materials and Methods: Thirty-six cylindrical and 36 tapered MSIs, 6 mm long, were used in this study. Half of each shape was 1.6 mm in diameter, while the other half was 2.0 mm. After pilot drilling, four and five MSIs were inserted, respectively, into fresh cadaveric maxillae and mandibles of dogs. Bone blocks containing the MSIs were sectioned and ground parallel to the MSI axis. Epifluorescent microscopy was used to measure overall cortical thickness, crack length, and crack number adjacent to the MSI. Crack density and total microdamage burden per surface length were calculated. Three-way analysis of variance (ANOVA) was used to test the effects of jaw, and MSI shape and diameter. Pairwise comparisons were made to control the overall significance level at 5%. Results: The larger (2.0 vs 1.6 mm) cylindrical MSIs increased the numbers, lengths, and densities of microcracks, and the total microdamage burden. The same diameter cylindrical and tapered MSIs generated a similar number of cracks and crack lengths. More total microdamage burden was created by the 2.0-mm cylindrical than the 2.0-mm tapered MSIs. Although higher crack densities were produced by the insertion of 1.6-mm tapered MSIs, there was no difference in total microdamage burden induced by 1.6-mm tapered and 1.6-mm cylindrical MSIs. Conclusions: Pilot drilling is effective in reducing microdamage during insertion of tapered MSIs. To prevent excessive microdamage, large diameter and cylindrical MSIs should be avoided. (Angle Orthod. 2015;85:859-867.)

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Microdamage in Cortical Bone due to the Overtightening of Orthodontic Microscrews

Cited by 73 publications

References 34 publications

Is miniscrew primary stability influenced by bone density?

Is miniscrew primary stability influenced by bone density?

Impact of Insertion Depth and Predrilling Diameter on Primary Stability of Orthodontic Mini-implants

Microdamage generation by tapered and cylindrical mini-screw implants after pilot drilling

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