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Orthodontics & Craniofacial Research Mar 2021Orthodontic bone screws (OBSs) provide intraoral anchorage by penetrating oral mucosa and seating firmly in basilar bone (BB). Retromolar (prosthetic-type) implants...
Orthodontic bone screws (OBSs) provide intraoral anchorage by penetrating oral mucosa and seating firmly in basilar bone (BB). Retromolar (prosthetic-type) implants introduced the extra-alveolar (E-A) concept for BB anchorage to move teeth throughout the alveolar process, but the clinical procedures were complex and expensive. Titanium alloy (Ti) miniscrews placed in inter-radicular (I-R) alveolar bone are more convenient and provide some tooth movement potential, but multiple screws are usually required and the devices often interfere with the path of tooth movement. The advantages of BB anchorage and the convenience of miniscrew are combined into the E-A OBS system. These miniscrews are relatively large in diameter (2 mm), and strong (stainless steel), which are placed intraorally in the BB of the infra-zygomatic crest (IZC) and mandibular buccal shelf (MBS). E-A OBSs provide osseous anchorage to retract the dentition and/or rotate either arch. Recovery of impactions is effectively managed with lever arm springs anchored with IZC or MBS bone screws. An emerging frontier is BB anchorage for correcting severe malocclusions with clear aligners. Since the osseous-anchored mechanics are complementary, fixed appliances and clear aligners can be used individually or in tandem to resolve a broad variety of malocclusions. This report summarizes current concepts for conservatively managing complex malocclusions such as severe crowding, skeletal discrepancies, asymmetries and impactions with the OBS system.
Topics: Bone Screws; Mandible; Orthodontic Anchorage Procedures; Orthodontic Appliance Design; Tooth Movement Techniques
PubMed: 33225592
DOI: 10.1111/ocr.12429 -
Veterinary and Comparative Orthopaedics... Sep 2022
Topics: Animals; Bone Plates; Bone Screws; Fracture Fixation, Internal; Biomechanical Phenomena
PubMed: 36257319
DOI: 10.1055/s-0042-1757756 -
Veterinary Surgery : VS Jul 2022Determine compression generated by lag and neutral screws over 12 h using two bone analogs.
OBJECTIVE
Determine compression generated by lag and neutral screws over 12 h using two bone analogs.
STUDY DESIGN
Experimental study.
SAMPLE POPULATION
Bone analogs were made of composite synthetic bone (CSB) or three-dimensional printed polylactic acid (PLA). Analogs had a 2 mm exterior shell with a 10 mm thick internal layer of open-cell material.
METHODS
Bone analogs were opposed, making a 4-sided box with open ends. A central channel contained the sensor and the screws passed through it to engage both paired analogs. Four screw/analog conditions were tested: neutral and lag screw with bicortical engagement, neutral and lag screw with unicortical engagement. All screws were tightened to 2 Nm torque and compression values recorded at 0, 0.5, 1, 2, 6, and 12 h (six trials per condition). Medians were compared across groups for statistical significance.
RESULTS
There was no difference in median compression between lag and neutral bicortical screws. For PLA, greater median compression was generated by neutral (median 437 N) and lag (median 379 N) bicortical screws compared to neutral unicortical screws (median 208 N, p < .001); lag bicortical screws generated greater median compression than lag unicortical screws (median 265 N, p = .012). For CSB, lag bicortical screws (median 293 N) generated greater median compression than neutral unicortical screws (median 228 N, p = .008).
CONCLUSION
Lag and neutral screws generated similar compression. Bicortical screws had higher median compression than unicortical screws in bone analogs.
CLINICAL SIGNIFICANCE
Neutral screws generate compression in cancellous bone analogs that can be increased with bicortical bone engagement.
Topics: Animals; Biomechanical Phenomena; Bone Screws; Cysts; Fracture Fixation, Internal; Horse Diseases; Horses; Polyesters
PubMed: 35394080
DOI: 10.1111/vsu.13814 -
Orthopedics Sep 2016Cancellous screws are designed to optimize fixation in metaphyseal bone environments; however, certain clinical situations may require the substitution of cortical... (Comparative Study)
Comparative Study
Cancellous screws are designed to optimize fixation in metaphyseal bone environments; however, certain clinical situations may require the substitution of cortical screws for use in cancellous bone, such as anatomic constraints, fragment size, or available instrumentation. This study compares the biomechanical properties of commercially available cortical and cancellous screw designs in a synthetic model representing various bone densities. Commercially available, fully threaded, 4.0-mm outer-diameter cortical and cancellous screws were tested in terms of pullout strength and maximum insertion torque in standard-density and osteoporotic cancellous bone models. Pullout strength and maximum insertion torque were both found to be greater for cancellous screws than cortical screws in all synthetic densities tested. The magnitude of difference in pullout strength between cortical and cancellous screws increased with decreasing synthetic bone density. Screw displacement prior to failure and total energy absorbed during pullout strength testing were also significantly greater for cancellous screws in osteoporotic models. Stiffness was greater for cancellous screws in standard and osteoporotic models. Cancellous screws have biomechanical advantages over cortical screws when used in metaphyseal bone, implying the ability to both achieve greater compression and resist displacement at the screw-plate interface. Surgeons should preferentially use cancellous over cortical screws in metaphyseal environments where cortical bone is insufficient for fixation. [Orthopedics.2016; 39(5):e828-e832.].
Topics: Bone Density; Bone Screws; Cancellous Bone; Cortical Bone; Device Removal; Equipment Design; Equipment Failure Analysis; Humans; Osteoporosis; Torque
PubMed: 27172369
DOI: 10.3928/01477447-20160509-01 -
Veterinary and Comparative Orthopaedics... 2013
Topics: Animals; Bone Plates; Bone Screws; Dog Diseases; Female; Male; Osteotomy; Stifle
PubMed: 23857578
DOI: 10.3415/VCOT-13-06-0072 -
The Veterinary Clinics of North... Sep 1999The treatment goal of fracture fixation is to restore the patient to normal function as quickly as possible. Fracture fixation can be accomplished by various means;... (Review)
Review
The treatment goal of fracture fixation is to restore the patient to normal function as quickly as possible. Fracture fixation can be accomplished by various means; fixation with screws and bone plates is not only a popular but a successful technique. In this article, the authors provide concepts that a surgeon must understand for successful screw and bone plate use. In addition, case examples demonstrating the application of many of the concepts are included.
Topics: Animals; Bone Plates; Bone Screws; Fracture Fixation, Internal; Fractures, Bone; Radiography
PubMed: 10503287
DOI: 10.1016/s0195-5616(99)50105-8 -
Journal of Orthopaedic Trauma Aug 2000
Topics: Bone Screws; Equipment Design; Fracture Fixation, Intramedullary; Humans; Terminology as Topic
PubMed: 11001424
DOI: 10.1097/00005131-200008000-00026 -
The Journal of Hand Surgery Feb 2015A plethora of screw designs and sizes are available from multiple companies for use in upper extremity surgery. Knowing the dimensions of screws is critical in the... (Comparative Study)
Comparative Study Review
A plethora of screw designs and sizes are available from multiple companies for use in upper extremity surgery. Knowing the dimensions of screws is critical in the treatment of bone of varying dimensions for fractures, osteotomies, or arthrodeses. Although many screws are named by their major thread diameter, this is not always true. Because of this confusing nomenclature and vast number of options, we sought to review the most commonly used screws and codify their dimensions into a readily available article and reference chart. This article highlights the basic dimensions of commonly used headless screws, stand-alone lag screws, non-locking and locking screws for plating, and biocomposite screws. Commonly described treatments using these screws include fixation of elbow, wrist, carpal, metacarpal, and phalangeal fractures and osteotomies, as well as arthrodeses of upper extremity joints. This article and its tables are by no means exhaustive of all commercially available implants. The focus is on the most commonly used implants in the United States as of 2014.
Topics: Arm; Arthrodesis; Bone Screws; Equipment Design; Fracture Fixation, Internal; Hand; Humans; Osteotomy; Terminology as Topic
PubMed: 25617959
DOI: 10.1016/j.jhsa.2014.11.012 -
Journal of Orthopaedic Trauma May 2020
Topics: Ankle Joint; Bone Screws; Research Design
PubMed: 31990762
DOI: 10.1097/BOT.0000000000001746 -
Veterinary Surgery : VS Nov 2017To determine whether 2.0 mm cancellous screws are superior to 2.0 mm cortical screws when inserted into cancellous and bicortical bone.
OBJECTIVE
To determine whether 2.0 mm cancellous screws are superior to 2.0 mm cortical screws when inserted into cancellous and bicortical bone.
STUDY DESIGN
Biomechanical study.
METHODS
The 2.0 mm cancellous screws and 2.0 mm cortical screws were inserted according to the recommended guidelines in synthetic cancellous and bicortical blocks. Fifteen screw-block constructs per group were tested to failure in axial pullout. Axial pullout strength and yield strength were calculated. Data were analyzed using a one-way ANOVA.
RESULTS
The 2.0 mm cortical screws achieved lower axial pullout strength than 2.0 mm cancellous screws in cancellous blocks. The 2.0 mm cortical screws achieved greater pullout strength than 2.0 mm cancellous screws in bicortical blocks.
CONCLUSION
The 2.0 mm cancellous screws may offer a biomechanical advantage in bone with thin cortices (<1 mm thick), whereas 2.0 mm cortical screws may be preferred in cortical bone with cortices measuring at least 1 mm in thickness.
Topics: Biomechanical Phenomena; Bone Screws; Cancellous Bone; Cortical Bone
PubMed: 28817191
DOI: 10.1111/vsu.12692