Histomorphometric analysis of bone tissue repair in rabbits after insertion of titanium screws under different torque

Togni, Fabrício; Baras, Fabíola; Ribas, Marina de Oliveira; Taha, Murched Omar

doi:10.1590/s0102-86502011000400003

Cited by 12 publications

(15 citation statements)

References 21 publications

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“…The holding power of cancellous screws inserted into a cadaveric femur through pilot holes smaller than those proposed by the manufacturer increased significantly the pullout strength. Unlike the vertebral cancellous bone, the use of a pilot hole smaller than the internal (core) screw diameter should be avoided in cortical bone because it causes cortical bone fissures and microcraks that lead to bone fixation failure [39]. The increased pullout strength effect of cancellous bone compression around the pedicle screw was also observed using a tap smaller than the screw diameter or untapped screw pedicle screw insertion [7].…”

Section: Discussionmentioning

confidence: 99%

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Effect of pilot hole on biomechanical and in vivo pedicle screw–bone interface

et al. 2013

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Purpose To experimentally study the influence of pilot hole diameter (smaller than or equal to the internal (core) diameter of the screw) on biomechanical (insertion torque and pullout strength) and histomorphometric parameters of screw-bone interface in the acute phase and 8 weeks after pedicle screw insertion. Methods Fifteen sheep were operated upon and pedicle screws inserted in the L1-L3 pedicles bilaterally. The pilot hole was smaller (2.0 mm) than the internal diameter (core) of the screw on the left side pedicle and equal (2.8 mm) to the internal diameter (core) of the screw on the right side pedicle. Ten animals were sacrificed immediately (five animals were assigned to pullout strength tests and five animals were used for histomorphometric bone-screw interface evaluation). Five animals were sacrificed 8 weeks after pedicle screw insertion for histomorphometric bonescrew interface evaluation. Results The insertion torque and pullout strength were significantly greater in pedicle screws inserted into pilot holes smaller than internal (core) diameter of the screw. Histomorphometric evaluation of bone-screw interface showed that the percentage of bone-implant contact, the area of bone inside the screw thread and the area of bone outside the screw thread were significantly higher for pilot holes smaller than the internal (core) diameter of the screw immediately after insertion and after 8 weeks. Conclusion A pilot diameter smaller than the internal (core) diameter of the screw improved the insertion torque and pullout strength immediately after screw insertion as well the pedicle screw-bone interface contact immediately and 8 weeks after screw placement in sheep with good bone mineral density.

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Section: Discussionmentioning

confidence: 99%

“…After screw insertion, initial healing involves bone remodeling in the vicinity of the screw, resembling the repair of bone fractures [19,39]. The screwbone interface was more active in screws inserted into smaller pilot holes.…”

Section: Discussionmentioning

confidence: 99%

Effect of pilot hole on biomechanical and in vivo pedicle screw–bone interface

et al. 2013

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“…Our results suggest that OMIs the thread depth to outer diameter ratio should not exceed 33% (1 to 3) in order to lower TF risk when OMIs are placed in dense bone. Lower IT values were associated with a trend towards less inflammation in the local bone tissue around the OMIs (20). …”

Section: Discussionmentioning

confidence: 99%

“…For self-drilling OMIs, the adequate IT may be somewhat higher (20). Using conical OMIs, especially Nos.…”

Section: Discussionmentioning

confidence: 99%

Design characteristics, primary stability and risk of fracture of orthodontic mini-Implants: Pilot scan electron microscope and mechanical studies

Walter¹,

Winsauer²,

Marcé‐Nogué³

et al. 2013

Med Oral

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Objectives: 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. Conclusions: 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. Key words:Orthodontic mini-implants, primary stability, insertion torque, pullout strength, torsional fracture.

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“…Oliveira et al [19] determined that, although the fabrication process parameters have been optimized, the ideal porous requirements for surgical implants have not yet been reached. These authors reported that some changes are necessary in order to increase porosity and advocated that an analysis of pore size distribution along the sample has been performed to indicate more efficiently which porous fraction would better meet implant requirements [21]. Togni et al [22] studied the histomorphometric analysis of bone tissue repair in rabbits after insertion of titanium screws under different torque.…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Titanium Plate with Anodic Oxidation and Its Application in Bone Growth

Fadlallah¹,

Quahtany²,

El-Shenawy³

2013

JBNB

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Using implants for dental applications are well-accepted procedures as one of the solutions for periodontal defect repair. Suitable design and materials, their reaction with the surrounding hard tissues and interfacial biomechanical properties are still considered to be the primary criteria which need to be addressed. The purpose of present study was to evaluate the bone repair around pure titanium implants and porous surface using anodic oxidation technique, after their insertion in tibiae of rats (n = 15). Five animals received pure titanium-surface implants in tibia, 5 rough-surface implants (TiO 2 /Ti) in tibia and last five acted as control group. The interfacial integrity and compositional variation along the interface were studied using scanning electron microscope (SEM) with energy dispersive analysis of X-ray (EDX) and histopathology after 2 months. The rats were sacrificed 8 weeks after surgery and fragments of the tibiae containing the implants were submitted to histological analyses to evaluate new bone formation at the implant-bone interface as well as the tibiae were radio graphed. The SEM-EDX results confirmed the initial stability for the Ti implant, but the regeneration of new bone formation was faster in the case of TiO 2 /Ti implant, and hence could be used for faster healing. The results of the histological analysis showed that osseointegration occurred for both types of implants with similar quality of bone tissue. In conclusion, the porous-surface implants contributed to the osseointegration because they provide a larger contact area with surface roughness at implant-bone interface can help into the formation of physico-chemical bondage with the surrounding hard tissues.

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Histomorphometric analysis of bone tissue repair in rabbits after insertion of titanium screws under different torque

Cited by 12 publications

References 21 publications

Effect of pilot hole on biomechanical and in vivo pedicle screw–bone interface

Effect of pilot hole on biomechanical and in vivo pedicle screw–bone interface

Design characteristics, primary stability and risk of fracture of orthodontic mini-Implants: Pilot scan electron microscope and mechanical studies

Surface Modification of Titanium Plate with Anodic Oxidation and Its Application in Bone Growth

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