Risks and complications of orthodontic miniscrews

doi:10.1016/j.ajodo.2006.04.027

American Journal of Orthodontics and Dentofacial Orthopedics

Volume 131, Issue 4, Supplement, April 2007, Pages S43-S51

https://doi.org/10.1016/j.ajodo.2006.04.027 Get rights and content

The risks associated with miniscrew placement should be clearly understood by both the clinician and the patient. Complications can arise during miniscrew placement and after orthodontic loading that affect stability and patient safety. A thorough understanding of proper placement technique, bone density and landscape, peri-implant soft-tissue, regional anatomic structures, and patient home care are imperative for optimal patient safety and miniscrew success. The purpose of this article was to review the potential risks and complications of orthodontic miniscrews in regard to insertion, orthodontic loading, peri-implant soft-tissue health, and removal.

Section snippets

Trauma to the periodontal ligament or the dental root

Interradicular placement of orthodontic miniscrews risks trauma to the periodontal ligament or the dental root. Potential complications of root injury include loss of tooth vitality, osteosclerosis, and dentoalveolar ankylosis.4, 5 Trauma to the outer dental root without pulpal involvement will most likely not influence the tooth's prognosis.⁶ Dental roots damaged by orthodontic miniscrews have demonstrated complete repair of tooth and periodontium in 12 to 18 weeks after removal of the

Stationary anchorage failure

According to the literature, the rates of stationary anchorage failure of miniscrews under orthodontic loading vary between 11% and 30%.39, 40, 41, 42 If a miniscrew loosens, it will not regain stability and will probably need to be removed and replaced.⁶ Stability of the orthodontic miniscrew throughout treatment depends on bone density, peri-implant soft tissues, miniscrew design, surgical technique, and force load.38, 43, 44, 45, 46, 47

The key determinant for stationary anchorage is bone

Aphthous ulceration

Minor aphthous ulcerations, or canker sores, can develop around the miniscrew shaft or on the adjacent buccal mucosa in contact with the miniscrew head. Aphthi are characterized as mildly painful ulcers affecting nonkeratinized mucosa.⁶⁷ Minor aphthous ulcerations are typically caused by soft-tissue trauma but might occur as a result of genetic predisposition, bacterial infection, allergy, hormonal imbalance, vitamin imbalance, and immunologic and psychologic factors.⁶⁷ Minor aphthous

Miniscrew fracture

The miniscrew head could fracture from the neck of the shaft during removal. The authors recommend a minimum diameter of 1.6 mm for self-drilling miniscrews that are 8 mm or longer placed in dense cortical bone. The proper placement technique can minimize the risk of miniscrew fracture during its removal. If the miniscrew fractures flush with the bone, the shaft might need to be removed with a trephine.⁶

Partial osseointegration

Although orthodontic miniscrews achieve stationary anchorage primarily through mechanical

PATIENT SELECTION AND HOME CARE

Orthodontic miniscrews are approved by the US Food and Drug Administration for adults and adolescents (age 12 and older).⁷³ Patients older than 12 who have not yet completed skeletal growth (as shown by a hand-wrist radiograph) should have palatal miniscrews placed away from the midline suture in the paramedian region.⁷³ Miniscrews are contraindicated in heavy smokers and patients with bone metabolic disorders.³⁸ Optimal oral hygiene is imperative to minimize miniscrew complications.

CONCLUSIONS

This article has highlighted the potential risks and complications of miniscrew placement with the hope of educating both clinician and patient. Bone density and soft-tissue health directly affect implant stability. Proper miniscrew home care by the patient is as important as proper placement by the orthodontist. Above all, maximum effort should be made to simplify the surgery and then modify the mechanics. Miniscrews are not a catholicon to be prescribed without precautions, but rather a

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Pull-out tests displayed linear behaviour until failure, whereas push-in tests showed increasing stiffness with more significant deformation. Higher torque led to higher capacity with a minor effect on the stiffness.
This paper provides insights into the mechanical behaviour of orthodontic mini-implants, offering guidance to orthodontic practitioners and researchers. Understanding how torque affects stability and performance under different loads informs the selection and design of mini-implants, potentially improving orthodontic treatments and patient outcomes.
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Temporary anchorage devices (TADs) are widely used in contemporary orthodontic treatments for anchorage purposes. This research aimed to investigate orthodontists’ attitude toward temporary anchorage devices (TADs) by surveying their TAD usage frequency and pricing and to identify factors influencing TAD usage frequency and pricing.
A structured, self-administered questionnaire with a total of 26 questions was randomly distributed to members of the Taiwanese Association of Orthodontics at the annual orthodontic meeting. The questionnaire comprised 6 questions on demographics, 10 questions on work patterns and patient type, and 10 questions on orthodontic technique. Responses were analyzed using a Pearson chi-Square test to identify factors of interest.
Factors associated with TAD usage frequency included degree of income satisfaction, number of working hours per week, and proportion of extraction-based treatments in treatment plans. Factors associated with TAD pricing included orthodontist age, geographic region of practice, and adult treatment fee.
More Taiwanese orthodontists use TADs compared with orthodontists in other countries. TADs have become universally accepted, but practitioners use them selectively. The main factor influencing TAD usage frequency was the proportion of extraction-based treatments in treatment plans, and those influencing TAD were orthodontist age, geographic region of practice, and adult treatment fee. These findings may be applicable to other parts of the world and should be investigated at an international level.
Biomimetic calcium phosphate coating on medical grade stainless steel improves surface properties and serves as a drug carrier for orthodontic applications
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Recently, stainless steel (SSL) miniscrew implants have been used in orthodontic clinics as temporary anchorage devices. Although they have excellent physical properties, their biocompatibility is relatively poor. Previously, our group developed a two-phase biomimetic calcium phosphate (BioCaP) coating that can significantly improve the biocompatibility of medical devices. This study aimed to improve the biocompatibility of SSL by coating SSL surface with the BioCaP coating.
Titanium (Ti) discs and SSL discs (diameter: 5 mm, thickness: 1 mm) were used in this study. To form an amorphous layer, the Ti discs were immersed in a biomimetic modified Tyrode solution (BMT) for 24 h. The SSL discs were immersed in the same solution for 0 h, 12 h, 24 h, 36 h and 48 h. To form a crystalline layer, the discs were then immersed in a supersaturated calcium phosphate solution (CPS) for 48 h. The surface properties of the BioCaP coatings were analysed. In addition, bovine serum albumin (BSA) was incorporated into the crystalline layer during biomimetic mineralisation as a model protein.
The morphology, chemical composition and drug loading capacity of the BioCaP coating on smooth SSL were confirmed. This coating improved roughness and wettability of SSL surface. In vitro, with the extension of BMT coating period, the cell seeding efficiency, cell spreading area and cell proliferation on the BioCaP coating were increased.
These in vitro results show that the BioCaP coating can improve surface properties of smooth medical grade SSL and serve as a carrier system for bioactive agents.
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The use of miniscrews during orthodontic treatment is reported to achieve vertical control when accompanied by the conventional preadjusted appliance for nonsurgical treatment. Two Chinese females with Class II skeletal malocclusion, high mandibular plane angle, retrognathic mandible, and convex profile were treated with orthodontic camouflage. Orthodontic miniscrews were placed in the posterior maxillary segments and the anterior maxilla to provide maximum anchorage and intrusion of teeth. This appliance system facilitated the counterclockwise rotation of the mandibular plane, resulting in an improved esthetic for the lower third of the face. After 10 years of retention, the two dentitions remain well aligned with ideal intercuspation and harmonious profile. Using orthodontic miniscrews for vertical control may be effective and stable in adult patients with hyperdivergent Class II skeletal patterns.
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Routine alignment with fixed appliances and aligners is indeterminate mechanics because equilibrium equations are only applicable to two abutments: teeth, segments, or arches. Orthodontists must depend on compliance and resilience of materials (archwires and aligners) for initial alignment. However, stabilized segments and arches are "large multirooted teeth" that can be moved with determinate mechanics using temporary skeletal anchorage devices. Temporary skeletal anchorage devices have advanced from retromolar implants and inter-radicular miniscrews to extra-alveolar bone screws placed in the basilar bone buccal to the first molars: mandibular buccal shelf and infrazygomatic crest. Extra-alveolar anchorage is determinate mechanics to move teeth, segments, and arches. Retraction and rotation of the lower arch reverses the etiology of Class III open bite malocclusion to correct severe skeletal dysplasia with no extractions or orthognathic surgery.
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Special ArticleRisks and complications of orthodontic miniscrews

Section snippets

Trauma to the periodontal ligament or the dental root

Stationary anchorage failure

Aphthous ulceration

Miniscrew fracture

Partial osseointegration

PATIENT SELECTION AND HOME CARE

CONCLUSIONS

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Semin Orthod

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J Am Dent Assoc

J Am Dent Assoc

J Oral Maxillofac Surg

J Craniomaxillofac Surg

Int J Oral Surg

Am J Orthod Dentofacial Orthop

J Prosthet Dent

J Craniomaxillofac Surg

Semin Orthod

Am J Orthod Dentofacial Orthop

Semin Orthod

Semin Orthod

Am J Orthod Dentofacial Orthop

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Risks and complications of orthodontic miniscrews