Acta Scientific Dental Sciences (ASDS)(ISSN: 2581-4893)

Review Article Volume 6 Issue 3

Extra-Alveolar Temporary Anchorage Devices and Considerations of Adjacent Anatomical Structures-A Review

Sweta Saravanan1 and Steve Jacob2*

1Consultant Orthodontist in private practice, Gurgaon, Haryana
2PG student, Manav Rachna dental college, Faridabad

*Corresponding Author: Sweta Saravanan, Consultant Orthodontist in private practice, Gurgaon, Haryana.

Received: January 13, 2022; Published: February 11, 2022


Extra-alveolar TADs offer the orthodontist elaborate tooth movements like en-masse distalization, expansion, mesialization etc. with an added advantage of preventing root damage. Although these TADs are placed away from roots, they are in close proximity to the adjacent anatomical structures at the area of placement. The most commonly used extra-alveolar TADs are the infra-zygomatic crest screws, the buccal shelf screws, palatal, retromolar and symphseal screws. For the IZC screws, the main anatomical structure to be considered is the maxillary sinus where up to 2mm of penetration is acceptable and more than 2mm can cause its significant damage. Similarly, for the buccal shelf screws, the inferior alveolar nerve is to be considered to avoid damage because the buccal shelf area shows ethnic variation in terms of thickness ad width. Similarly, the retromolar, symphseal and palatal screws also have their adjacent anatomical structures to be kept in mind before their placement and use. This review aims to elaborate ideal sites of placement of extra-alveolar TADs and anatomical considerations of the adjacent anatomical structures to be kept in mind while placing them to prevent the injury and failure of the implants

Keywords: Extra-Alveolar; Anchorage; Anchorage; TADs; Maxillary Sinus


  1. Gainsforth BL and Higley LB. “A study of orthodontic anchorage possibilities in basal bone”. American Journal of Orthodontics and Oral Surgery 8 (1945): 406-417.
  2. Park HS Almeida MR. “Biomechanics of extra-alveolar mini-implants”. Dental press journal of orthodontics4 (2019): 93-109.
  3. Hyo-Sang Park., et al. “Group distal movement of teeth using microscrew implant anchorage”. The Angle Orthodontist 75 (2005): 602-609.
  4. Chang C. “Clinical applications of orthodontic bone screw in Beethoven orthodontic center”. International Association for Orthodontists and Implantologists 23 (2011): 50-51.
  5. Nanda R “Dr. Ravindra Nanda on orthodontic mechanics. Interview byRobert G Keim”. Journal of Clinical Orthodontics 5 (2010): 293-3020.
  6. Almeida MR. “Biomechanics of extra-alveolar mini-implants”. Dental press journal of orthodontics4 (2019): 93-1090.
  7. “Temporary Anchorage Devices in Clinical Orthodontics”. First Edition. Edited by Jae Hyun Park© (2020).
  8. Baumgaertel S and Hans MG. “Assessment of infrazygomatic bone depth for mini-screw insertion”. Clinical Oral Implants Research6 (2019): 638-642.
  9. CBCT Imaging to Diagnose and Correct the Failure of Maxillary Arch Retraction with IZC Screw Anchorage
  10. Murugesan A and Sivakumar A. “Comparison of bone thickness in infrazygomatic crest area at various miniscrew insertion angles in Dravidian population - A cone beam computed tomography study”. International Orthodontics 1 (2020): 105-114.
  11. Iwanaga J., et al. “Clinical anatomy of the maxillary sinus: application to sinus floor augmentation”. Anatomy and Cell Biology1 (2019): 17-24.
  12. Motoyoshi., et al. “Maxillary sinus perforation by orthodontic anchor screws”. Journal of Oral Science 57 (2015): 95-100.
  13. Gracco A., et al. “Miniscrew insertion and the maxillary sinus: an endoscopic evaluation”. Journal of Clinical Orthodontics 7 (2010): 439-443.
  14. Liu H., et al. “Safe zones for miniscrews in maxillary dentition distalization assessed with cone-beam computed tomography”. American Journal of Orthodontics and Dentofacial Orthopedics 3 (2017): 500-506.
  15. Kravitz ND and Kusnoto B. “Risks and complications of orthodontic miniscrews”. American Journal of Orthodontics and Dentofacial Orthopedics4 (2007): S43-51.
  16. Chaturvedi S., et al. “CBCT analysis of Schneiderian membrane thickness and its relationship with gingival biotype and arch form”. Nigerian Journal of Clinical Practice 22 (2019): 1448-1456.
  17. Vibhute PJ and Patil PA. “Inferior Level of Maxillary Sinus and Cortical Bone Thickness at Maxillary Posterior Quadrant, in Three Different Growth Patterns: 3D-Computed Tomographic Study”. Journal of Oral Implants 2014 (2014).
  18. Brånemark PI., et al. “An experimental and clinical study of osseointegrated implants penetrating the nasal cavity and maxillary sinus”. Journal of Oral and Maxillofacial Surgery8 (1984): 497-505.
  19. Ardekian L., et al. “The clinical significance of sinus membrane perforation during augmentation of the maxillary sinus”. Journal of Oral and Maxillofacial Surgery2 (2006): 277-282.
  20. Nolan PJ., et al. “Correlation Between Schneiderian Membrane Perforation and Sinus Lift Graft Outcome: A Retrospective Evaluation of 359 Augmented Sinus”. Journal of Oral and Maxillofacial Surgery1 (2014): 47-52.
  21. Zhong W., et al. “Experimental study on penetration of dental implants into the maxillary sinus in different depths”. Journal of Applied Oral Science6 (2013): 560-566.
  22. Insua A., et al. “Accuracy of Schneiderian membrane thickness: a cone-beam computed tomography analysis with histological validation”. Clinical Oral Implants Research6 (2016): 654-661.
  23. Jia X., et al. “Influence of orthodontic mini-implant penetration of the maxillary sinus in the infrazygomatic crest region”. American Journal of Orthodontics and Dentofacial Orthopedics5 (2018): 656-661.
  24. Elshebiny T., et al. “Anatomic assessment of the mandibular buccal shelf for miniscrew insertion in white patients”. American Journal of Orthodontics and Dentofacial Orthopedics4 (2018): 505-511.
  25. Kolge NE., et al. “Tomographic mapping of buccal shelf area for optimum placement of bone screws: A three-dimensional cone-beam computed tomography evaluation”. APOS Trends in Orthodontics4 (2019): 241-245.
  26. Gandhi V., et al. “Variability associated with mandibular buccal shelf area width and height in subjects with different growth pattern, sex, and growth status”. American Journal of Orthodontics and Dentofacial Orthopedics (2020).
  27. Nucera R., et al. “Bone and cortical bone thickness of mandibular buccal shelf for mini-screw insertion in adults”. The Angle Orthodontist5 (2017): 745-751.
  28. Parinyachaiphun S., et al. “Considerations for placement of mandibular buccal shelf orthodontic anchoring screw in Class III hyperdivergent and normodivergent subjects-A cone beam computed tomography study”. Orthodontic Waves1 (2018): 44-56.
  29. Chang C., et al. “Primary failure rate for 1680 extra-alveolar mandibular buccal shelf mini-screws placed in movable mucosa or attached gingiva”. Angle Orthodontic6 (2015): 905-910.
  30. Motoyoshi M., et al. “Recommended placement torque when tightening an orthodontic mini-implant”. Clinical Oral Implants Research 1 (2006): 109-114.
  31. Chang CH., et al. “Insights to Extraradicular Bone Screw Applications for Challenging Malocclusions”. Temporary Anchorage Devices in Clinical Orthodontics (2020): 433-444.
  32. Chang CC., et al. “Extra-alveolar bone screws for conservative correction of severe malocclusion without extractions or orthognathic surgery”. Current Osteoporosis Reports4 (2018): 387-394.
  33. Nanda R., et al. “Temporary Anchorage Devices in Orthodontics E-Book”. Elsevier Health Sciences (2019).
  34. Helwany M and Rathee M. “Anatomy, Head and Neck, Palate. In: StatPearls”. Treasure Island (FL): StatPearls Publishing (2020).
  35. Hourfar J., et al. “Three dimensional anatomical exploration of the anterior hard palate at the level of the third rugae for the placement of mini-implants - a cone-beam CT study”. The European Journal of Orthodontics6 (2015): 58.
  36. Becker K., et al. “Is there an ideal insertion angle and position for orthodontic mini-implants in the anterior palate? A CBCT study in humans”. American Journal of Orthodontics and Dentofacial Orthopedics3 (2019): 345-354.
  37. Gracco A., et al. “Quantitative cone-beam computed tomography evaluation of palatal bone thickness for orthodontic miniscrew placement”. American Journal of Orthodontics and Dentofacial Orthopedics3 (2008): 361-369.
  38. Ludwig B., et al. “Anatomical guidelines for miniscrew insertion: palatal sites”. Journal of clinical orthodontics: JCO8 (2011): 433.


Citation: Sweta Saravanan and Steve Jacob. “Extra-Alveolar Temporary Anchorage Devices and Considerations of Adjacent Anatomical Structures-A Review”. Acta Scientific Dental Sciences 6.3 (2022): 20-27.


Copyright: © 2022 Sweta Saravanan and Steve Jacob. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Acceptance rate30%
Acceptance to publication20-30 days
Impact Factor1.278

Indexed In

News and Events

  • Certification for Review
    Acta Scientific certifies the Editors/reviewers for their review done towards the assigned articles of the respective journals.
  • Submission Timeline for Upcoming Issue
    The last date for submission of articles for regular Issues is July 30, 2024.
  • Publication Certificate
    Authors will be issued a "Publication Certificate" as a mark of appreciation for publishing their work.
  • Best Article of the Issue
    The Editors will elect one Best Article after each issue release. The authors of this article will be provided with a certificate of "Best Article of the Issue"
  • Welcoming Article Submission
    Acta Scientific delightfully welcomes active researchers for submission of articles towards the upcoming issue of respective journals.

Contact US