Orthodontic Anchorage Unit Research Study

Chapter 3 MATERIALS AND METHODS

A three-dimensional bone block model (Figure 2) integrated with a miniscrew was constructed with a computer-aided design program (SolidWorks; Dassault Systemes SolidWorks, Concord, Mass) to simulate a miniscrew implanted in bone as an orthodontic anchorage unit.

Figure 2. Three dimensional bone block model with screw embedded.

The bone block, consisting of cortical and cancellous bone, was constructed with dimensions of 20 mm. in length and width, and 15 mm. in height for evaluation. [1] The cortical bone thickness, elastic moduli, Poisson’s ratio, shear moduli and density of the edentulous maxillary and mandibular alveolar bone as shown on Table 2 was based on the studies of Dechow et al.[2] and Schwartz-Dabney and Dechow[3], respectively; and the dentate specimen based on the study of Peterson et al. [4] These were taken from specific locations of the edentulous maxillary and mandibular alveolar bone as shown in Figure 3. Since cancellous bone density was found to have little or no consequence to results obtained by previous studies[5], a fixed value will be set with elastic moduli of 1.3 GPa, Poisson’s ratio of 0.3, shear moduli of 2.0 and density 0.5g/cm³.

Figure 3. Location from which cortical bone specimens were removed from the edentulous crania by Dechow et al.[6] and the edentulous mandibles by Schwartz-Dabney and Dechow[7]

Are Writing Services Legal?

Totally! They’re a legit resource for sample papers to guide your work. Use them to learn structure, boost skills, and ace your grades—ethical and within the rules.

The miniscrew geometry was based on the MONDEAL system (MONDEAL Medical Systems, Muhlheim, Germany): ie, the screw thread profile was an isosceles triangle 0.4 mm in height and 0.16 mm along the base.[8] The thread pitch was 1.0 mm. These thread dimensions were fixed in all screw designs in this study. The miniscrew will be assumed to be homogeneous, isotropic and linearly elastic titanium alloy (Ti-6Al-4V) with elastic modulus of 114 GPa, Poisson’s ratio or 0.34 and Yield strength of 880MPa.[9]

Table 2. Material properties of maxillary[10] and mandibular[11] alveloar cortical bone.

	CBT (mm) What’s the Price for a Paper? Starts at $10/page for undergrad, up to $21 for pro-level. Deadlines (3 hours to 14 days) and add-ons like VIP support adjust the cost. Discounts kick in at $500+—save more with big orders!	Elastic Moduli (GPa)	Poisson’s ratio	Shear moduli (GPa)	Density (g/cm3) Is My Privacy Protected? 100%! We encrypt everything—your details stay secret. Papers are custom, original, and yours alone, so no one will ever know you used us.
E1	E2	E3	V12 Is AI Involved in Writing? Nope—all human, all the time. Our writers are pros with real degrees, crafting unique papers with expertise AI can’t replicate, checked for originality.	V31	V23	G12	G31 Why Are You the Best for Research? Our writers are degree-holding pros who tackle any topic with skill. We ensure quality with top tools and offer revisions—perfect papers, even under pressure.	G23
Mx Edentate1	1.0	8.7 Who Writes My Assignments? Experts with degrees—many rocking Master’s or higher—who’ve crushed our rigorous tests in their fields and academic writing. They’re student-savvy pros, ready to nail your essay with precision, blending teamwork with you to match your vision perfectly. Whether it’s a tricky topic or a tight deadline, they’ve got the skills to make it shine.	9.9	11.9	0.23	0.25 Will My Paper Be Unique? Guaranteed—100%! We write every piece from scratch—no AI, no copying—just fresh, well-researched work with proper citations, crafted by real experts. You can grab a plagiarism report to see it’s 95%+ original, giving you total peace of mind it’s one-of-a-kind and ready to impress.	0.27	3.6	3.7	3.8 Can You Use Any Citation Format? Yep—APA, Chicago, Harvard, MLA, Turabian, you name it! Our writers customize every detail to fit your assignment’s needs, ensuring it meets academic standards down to the last footnote or bibliography entry. They’re pros at making your paper look sharp and compliant, no matter the style guide.	1.69
Mx Edentate2	0.7	6.9 Can I Change My Order Details? For sure—you’re not locked in! Chat with your writer anytime through our handy system to update instructions, tweak the focus, or toss in new specifics, and they’ll adjust on the fly, even if they’re mid-draft. It’s all about keeping your paper exactly how you want it, hassle-free.	9.5	11.1	0.20	0.20 How Do I Order a Paper? It’s a breeze—submit your order online with a few clicks, then track progress with drafts as your writer brings it to life. Once it’s ready, download it from your account, review it, and release payment only when you’re totally satisfied—easy, affordable help whenever you need it. Plus, you can reach out to support 24/7 if you’ve got questions along the way!	0.28	3.1	3.1	3.7 How Quick Can You Write? Need it fast? We can whip up a top-quality paper in 24 hours—fully researched and polished, no corners cut. Just pick your deadline when you order, and we’ll hustle to make it happen, even for those nail-biting, last-minute turnarounds you didn’t see coming.	1.66
Mx Edentate3	0.7	7.2	9.8 Can You Handle Tough Topics? Absolutely—bring it on! Our writers, many with advanced degrees like Master’s or PhDs, thrive on challenges and dive deep into any subject, from obscure history to cutting-edge science. They’ll craft a standout paper with thorough research and clear writing, tailored to wow your professor.	11.5	0.22	0.23	0.30	3.2 How Do You Match Professor Expectations? We follow your rubric to a T—structure, evidence, tone. Editors refine it, ensuring it’s polished and ready to impress your prof.	3.2	3.8	1.68
Mx Edentate4 How Do You Edit My Work? Send us your draft and goals—our editors enhance clarity, fix errors, and keep your style. You’ll get a pro-level paper fast.	0.7	7.1	10.3	11.8	0.18 Can You Brainstorm Topics? Yep! We’ll suggest ideas tailored to your field—engaging and manageable. Pick one, and we’ll build it into a killer paper.	0.18	0.25	3.3	3.3	3.8	1.63
Md Edentate1 Do You Offer Fast Edits? Yes! Need a quick fix? Our editors can polish your paper in hours—perfect for tight deadlines and top grades.	3.1	13.8	15.8	29.5	0.26	0.41 Can You Start With an Outline? Sure! We’ll sketch an outline for your approval first, ensuring the paper’s direction is spot-on before we write.	0.23	5.5	6.2	6.8	1.94
Md Edentate2	2.7	13.6 Can You Add Charts or Stats? Definitely! Our writers can include data analysis or visuals—charts, graphs—making your paper sharp and evidence-rich.	17.5	29.5	0.28	0.42	0.18	4.9	6.0	7.1	1.96
Md Edentate3 What About Multi-Part Projects? We’ve got it—each section delivered on time, cohesive and high-quality. We’ll manage the whole journey for you.	2.5	13.6	16.9	27.4	0.28 Do You Adapt to International Rules? Yes! UK, US, or Aussie standards—we’ll tailor your paper to fit your school’s norms perfectly.	0.44	0.21	5.0	5.7	7.4 What does a complex assignment mean? If your assignment needs a writer with some niche know-how, we call it complex. For these, we tap into our pool of narrow-field specialists, who charge a bit more than our standard writers. That means we might add up to 20% to your original order price. Subjects like finance, architecture, engineering, IT, chemistry, physics, and a few others fall into this bucket—you’ll see a little note about it under the discipline field when you’re filling out the form. If you pick “Other” as your discipline, our support team will take a look too. If they think it’s tricky, that same 20% bump might apply. We’ll keep you in the loop either way!	1.97
Md Edentate4	2.3	13.3 Who is my writer? How can I communicate with him/her? Our writers come from all corners of the globe, and we’re picky about who we bring on board. They’ve passed tough tests in English and their subject areas, and we’ve checked their IDs to confirm they’ve got a master’s or PhD. Plus, we run training sessions on formatting and academic writing to keep their skills sharp. You’ll get to chat with your writer through a handy messenger on your personal order page. We’ll shoot you an email when new messages pop up, but it’s a good idea to swing by your page now and then so you don’t miss anything important from them.	18.8	26.9	0.22	0.46	0.22	4.9	6.0	7.2	1.95
Mx dentate 2[12]	2.4	7.2	8.7	12.2	0.42	0.50	0.50	2.8	3.5	4.2	1.59

The model was meshed automatically with 10-node tetrahedral solid elements. The interface between the cortex and the cancellous bone was assumed to be fully bonded; i.e., the elements were continuous, sharing the same nodes along the interface. A node-to-node contact condition was given on the interface between the miniscrew and the bone block to imitate a stage without osseointegration.[13]

The static load along the x-axis was applied to the head of the miniscrew and perpendicular to its long axis to simulate the orthodontic force. For the nodes located on the 5 exterior surfaces of the bone block, all but the superior surface where the miniscrew entered was constrained in all degrees of freedom to simulate the boundary condition. The nodal solution of the von Mises stress in the bone and the displacement of the miniscrew were calculated for each model with the finite element analysis program.[14]

To determine the loading effect, the maxillary and mandibular bone blocks will be subjected to four force magnitudes (1, 2, 4 and 6 N) and three force directions (60^o , 90^o and 120^o) to mimic various clinical conditions. A force direction of 90^o was the force perpendicular to the long axis of the miniscrew and parallel to the bone surface.[15] 2 N is the reported clinically safe limit for immediate loading.[16] The loads will be applied at the level of the eye of the screw meant for tying ligatures in a clinical situation.[17]

To determine the screw size effect, three screw (outer) diameters (1.5, 2.0 and 2.3 mm.) and five screw length (7, 9, 11, 13 and 15 mm.). The screw length will be measured including the screw head, which had a 2 mm. height for all screw models. To simulate soft tissue thickness, various screw depths (screw length in the bone block) will be modelled.[18] For each screw length, the exposed screw length of 3, 4, 5 mm. will be measured.

The von Mises stress and the displacement was determined for the different screw length, diameter and exposed screw length was subjected to the different force magnitude and direction. For every bone specimen there was 540 different scenarios. The stress distribution was then observed for the screws that exhibited the highest stress for each bone specimen and for each force direction.

Chapter 5

SUMMARY OF FINDINGS, CONCLUSION AND RECOMMENDATIONS

Summary of Findings

There is no direct relationship between stress and displacement established. The pattern of the von Mises stress of miniscrews embedded on different bones are similiar with only minor differences. Whereas the maxillary edentulous specimens showing more displacement compared to its mandibular counterpart. Though the highest stress and highest displacement can be observed in 6 N of force at 90^o direction at 5 mm. exposed length and the lowest stress and lowest displacement can be observed in 1 N of force at 120⁰ direction at 3 mm. exposed length.

The stress is concentrated on the cortical bone irrespective of the screw length and the exposed screw length. It is more intensified at 5 mm exposed screw length because the moment of arm becomes longer, and lighter at 3 mm exposed length because the moment arm becomes shorter. The cortical bone acts as the fulcrum of the force.

All miniscrews embedded in mandibular edentulous specimens were able to establish primary stability except for 2 scenarios in MDE4. 12-13% of miniscrews embedded on maxillary edentulous specimen were not able to establish primary stability. Majority of these occurred with screw diameter of 1.5 mm. (78 – 85%), exposed screw length of 5 mm. (61 – 72%), force magnitude of 6 N. (62 – 68 %), and force angle of 90⁰ (40 – 45%).

Conclusion

Based on the data gathered, it is found that placement of orthodontic miniscrew on edentulous alveolar bone on both the maxilla and mandible is possible. The use of miniscrew with diameter of 2mm or wider embedding it on attached gingiva of 2mm or thinner, loading it with force 2 N or lower at an angle 60 or 120⁰ could increase chances of establishing primary stability.

Recommendations

The proponent of this research would like to recommend the implementation of a Randomized Controlled Trial based on the results of this study. This would ensure the evidence-based practice of the miniscrew anchorage.

 

References

[1] T. C. Liu and others, ‘Finite Element Analysis of Miniscrew Implants Used for Orthodontic Anchorage’, Am J Orthod Dentofacial Orthop, 141 (2012).

[2] P. C. Dechow, Q. Wang, and J. Peterson, ‘Edentulation Alters Material Properties of Cortical Bone in the Human Craniofacial Skeleton: Functional Implications for Craniofacial Structure in Primate Evolution’, The Anatomical Records: Advances in Integrative Anatomy and Evolutionary Biology, 293 (2010).

[3] C. L. Schwartz-Dabney and P. C. Dechow, ‘Edentulation Alters Material Properties of Cortical Bone in the Human Mandible’, J Dent Res, 81 (2002).

[4] J. Peterson, Q. Wang, and P. C. Dechow, ‘Material Properties of the Dentate Maxilla’, Anat Rec A Discov Mol Cell Evol Biol, 288 (2006).

[5] A. Gracco and others, ‘Numerical/Experimental Analysis of the Stress Field around Miniscrews for Orthodontic Anchorage’, Eur J Orthod, 31 (2009).

[6] Dechow, Wang, and Peterson.

[7] Schwartz-Dabney and Dechow.

[8] Liu and others

[9] Gerhard Welsch, R. Boyer, and E.W. Collings, Materials Properties Handbook: Titanium Alloys, (Asm International, 1994).

[10] Dechow, Wang, and Peterson.

[11] Schwartz-Dabney and Dechow.

[12] Peterson, Wang, and Dechow.

[13] Liu and others

[14] Ibid.

[15] Ibid.

[16] A. G. Crismani and others, ‘Miniscrews in Orthodontic Treatment: Review and Analysis of Published Clinical Trials’, Am J Orthod Dentofacial Orthop, 137 (2010).

[17] S. Singh and others, ‘Three-Dimensional Finite Element Analysis of Strength, Stability, and Stress Distribution in Orthodontic Anchorage: A Conical, Self-Drilling Miniscrew Implant System’, Am J Orthod Dentofacial Orthop, 141 (2012).

[18] Liu and others

Tags: Academic Writing Help, Ace Tutors, Assignment Help Solutions, Essay Writing Support