COMPARATIVE STUDY ON KEY SUCCESS FACTORS ON TWO DIFFERENT MINI IMPLANT SYSTEMS: SELF- DRILLING AND SELF-TAPPING.

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GYEONG WON JANG

2018, Group 15

COMPARATIVE STUDY ON KEY SUCCESS FACTORS ON

TWO DIFFERENT MINI IMPLANT SYSTEMS:

SELF-DRILLING AND SELF-TAPPING.

A systematic review

Assist. Judita Naujokaitytė

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2 Kaunas, 2018

LITHUANIAN UNIVERSITY OF HEALTH SCIENCE MEDICAL ACADEMY

FACULTY OF ODONTOLOGY DEPARTMENT OF ORTHODONTICS

COMPARATIVE STUDY ON KEY SUCCESS FACTORS ON TWO DIFFERENT MINI IMPLANT SYSTEMS: SELF-DRILLING AND SELF-TAPPING.

A systematic review Master’s Thesis

This thesis was done

by Student ... (Signature)

Supervisor ... (Signature)

... (Name, Surname, Course, Group)

... (Degree, Name, Surname)

... 20...m. (Day/Month)

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3 Kaunas, 2018

EVALUATION TABLE OF THE MASTER’S THESIS OF THE TYPE OF SYSTEMIC REVIEW OF SCIENTIFIC LITERATURE

Evaluation: ... Reviewer: ...

(scientific degree. name and surname)

Reviewing date: ...

Compliance with MT

No. MT parts MT evaluation aspects requirements and

evaluation Yes Partially No 1

Summary (0.5 point)

Is summary informative and in compliance with the

thesis content and requirements? 0.3 0.1 0

2 Are keywords in compliance with the thesis _essence? 0.2 0.1 0

3 _{Introduction,} aim and tasks

(1 point)

Are the novelty, relevance and significance of the

work justified in the introduction of the thesis? 0.4 0.2 0 4 Are the problem, hypothesis, aim and tasks formed _{clearly and properly?} 0.4 0.2 0

5 Are the aim and tasks interrelated? 0.2 0.1 0

6 Selection criteria of the studies, search methods and strategy (3.4 points)

Is the protocol of systemic review present? 0.6 0.3 0

7

Were the eligibility criteria of articles for the selected protocol determined (e.g., year, language, publication condition, etc.)

0.4 0.2 0

8

Are all the information sources (databases with dates of coverage, contact with study authors to identify additional studies) described and is the last search day indicated?

0.2 0.1 0

9

Is the electronic search strategy described in such a way that it could be repeated (year of search, the last search day; keywords and their combinations; number of found and selected articles according to the combinations of keywords)?

0.4 0.1 0

10

Is the selection process of studies (screening, eligibility, included in systemic review or, if applicable, included in the meta-analysis) described?

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4 11

Is the data extraction method from the articles (types of investigations, participants, interventions, analysed factors, indexes) described?

0.4 0.2 0

12

Are all the variables (for which data were sought and any assumptions and simplifications made) listed and defined?

0.4 0.2 0

13

Are the methods, which were used to evaluate the

risk of bias of individual studies and how this 0.2 0.1 0

information is to be used in data synthesis, described?

14 Were the principal summary measures (risk ratio,

difference in means) stated? 0.4 0.2 0

15 Systemizati on and analysis of data (2.2 points)

Is the number of studies screened: included upon assessment for eligibility and excluded upon giving the reasons in each stage of exclusion presented?

0.6 0.3 0

16

Are the characteristics of studies presented in the included articles, according to which the data were extracted (e.g., study size, follow-up period, type of respondents) presented?

0.6 0.3 0

17

Are the evaluations of beneficial or harmful outcomes for each study presented? (a) simple summary data for each intervention group; b) effect estimates and confidence intervals)

0.4 0.2 0

18

Are the extracted and systemized data from studies presented in the tables according to individual tasks?

0.6 0.3 0

19

Discussion (1.4 points)

Are the main findings summarized and is their

relevance indicated? 0.4 0.2 0

20 Are the limitations of the performed systemic review _discussed? 0.4 0.2 0

21 Does author present the interpretation of the results? 0.4 0.2 0

22

Conclusions (0.5 points)

Do the conclusions reflect the topic, aim and tasks of

the Master’s thesis? 0.2 0.1 0

23 Are the conclusions based on the analysed material? 0.2 0.1 0

24 Are the conclusions clear and laconic? 0.1 0.1 0

25

References (1 point)

Is the references list formed according to the

requirements? 0.4 0.2 0

26

Are the links of the references to the text correct? Are the literature sources cited correctly and precisely?

0.2 0.1 0

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5 28

Do the cited sources not older than 10 years old form at least 70% of sources, and the not older than 5 years – at least 40%?

0.2 0.1 0

Additional sections, which may increase the collected number of points 29 Annexes Do the presented annexes help to understand the

analysed topic? +0.2 +0.1 0

30

Practical recommend

ations

Are the practical recommendations suggested and are

they related to the received results? +0.4 +0.2 0

31

Were additional methods of data analysis and their results used and described (sensitivity analyses, meta-regression)?

+1 +0.5 0

32

Was meta-analysis applied? Are the selected

statistical methods indicated? Are the results of each meta-analysis presented?

+2 +1 0

General requirements, non-compliance with which reduce the number of points 33

General requirement

s

Is the thesis volume sufficient (excluding annexes)?

15-20 pages (-2 points)

<15 pages (-5 points) 34 Is the thesis volume increased artificially? -2 points -1 point

35 Does the thesis structure satisfy the _{requirements of Master’s thesis?} -1 point -2 points

36 Is the thesis written in correct language, _{scientifically, logically and laconically?} -0.5 point -1 points

37 Are there any grammatical, style or

computer literacy-related mistakes? -2 points -1 points

38 Is text consistent, integral, and are the _{volumes of its structural parts balanced?} -0.2 point -0.5 points

39 Amount of plagiarism in the thesis. >20%

(not evaluated)

40

Is the content (names of sections and subsections and enumeration of pages) in compliance with the thesis structure and aims?

-0.2 point -0.5 points

41

Are the names of the thesis parts in compliance with the text? Are the titles of sections and sub-sections distinguished logically and correctly?

42 Are there explanations of the key terms and

abbreviations (if needed)? -0.2 point -0.5 points

43

Is the quality of the thesis typography (quality of printing, visual aids, binding) good?

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6

*Remark: the amount of collected points may exceed 10 points.

Reviewer’s comments: _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ ____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ ___________________________________________________________________________________________________________________ _________________________________________ _________________________________________ Reviewer’s name and surname Reviewer’s signature

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7 Table of Contents

Abstract ...9

1. Introduction ...10

1.1. Aims of research ...12

2. Material and Search Methods ...12

2.1. Criteria of Included Studies...13

2.2. Criteria of Encluded Studies ...13

2.3. Search Strategy ...13

2.4. Systemization and Analysis of Data ...13

2.5. Quality of assessment ...17

3. Results ...18

3.1. Search Results ...18

3.2. Characteristics of Included Studies ...18

4. Discussion ...21 4.1. Success Rate ...21 4.2. Gender ...22 4.3. Age ...23 4.4. Pain frequency ...23 4.5. Shape of mini-implants ...23

4.6. Length and diameter of mini-implants ...24

4.7. Left or right mini-implant on inflammation ...24

4.8. Cortical bone thickness ...24

4.9. Rate of root contact ...25

4.10. Mobility of mini-implants ...25 4.11. Shape of mini-implants ...25 4.12. Shape of mini-implants ...26 5. Conclusion ...28 6. References ...30 7. Annex ...33

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8 EVALUATION FORM OF THE MASTER’S THESIS FOR THE MEMBER OF DEFENCE

COMMITTEE

Graduate student _____________________________________________________________________________________________, of the year ______, and the group _____ of the integrated study programme of Odontology

Master’s Thesis title: ………...……….………...……….. ………...….………...……...

No. MT evaluation aspects Evaluation

Yes Partially No 1 Has the student’s presentation lasted for more than 10 minutes?

2 Has the student presented the main problem of the Master’s _{thesis, its aim and tasks?}

3 Has the student provided information on research methodology and main research instruments?

4 Has the student presented the received results comprehensively?

5 Have the visual aids been informative and easy to understand?

6 Has the logical sequence of report been observed?

7 Have the conclusions been presented? Are they resulting from the results?

8 Have the practical recommendations been presented?

9 Have the questions of the reviewer and commission’s members been answered correctly and thoroughly?

10 Is the Master’s thesis in compliance with the essence of the selected study programme?

of the member of evaluation committee of Master’s Thesis

_____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________ Evaluation of the Master’s Thesis

_____________________________________________________________________________________________________________________ Member of the MT evaluation committee:

_______________________ _____________________________________ _____________________________________

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9 Abstract

Objectives: The research objective of this systematic review is to analyse key success factors of self-drilling and self-tapping mini-implants and to determine the efficiency of usage between both mini-implant systems in orthodontic practice.

Purpose: The master thesis is aimed to evaluate efficient treatment between drilling and self-tapping mini-implants in orthodontic practice. Also, to compare the key success factors correlated with success rate in two different mini-implant systems: success rates, gender, age, pain frequency, shapes of mini-implants, length and diameter of mini-implants, mobility, left or right side of jaw, cortical bone thickness, rate of root contact and loading force.

Methods and Materials: Relevant literature were determined by searching Google Scholar, PubMed, American Journal of Orthodontics and Dentofacial Orthopedics (AJO-DO), and

ScienceDirect electronic databases and they have been assessible for full-text version, information search for controlled studies on humans published between 2008 till 2018. Inclusion criteria were: English language, studies on humans, randomized or controlled clinical studies, assessment of self-drilling and self-tapping mini-implants in orthodontic practice. The quality assessment of the included articles was achieved.

Results: In total 670 scientific publications, articles, clinical trials were identified in the review by keywords during the research. In total 10 clinical studies satisfied all inclusion criteria. articles were selected in the review and 12 clinical studies were suitable for all inclusion criteria. The hypothesis was that self-drilling mini-implants are more effective than self-tapping in a comparison among overall success factors. The results were not statistically significant according to the level of statistical significance was at P<0.05 and different testimony.

Conclusion: The hypothesis was rejected due to finding that due to the implied -finding. Both self-tapping and the self-drilling mini-implants are effective anchorage units. Nevertheless, self-self-tapping mini-implants are still recommended for areas with high bone density and thick cortical bone where self-drilling mini-implants are not useful. Both techniques are beneficial to use as alternative one another. However, this systematic review presents that initial stability cannot be guaranteed or predicted. All of data chart showed different results on genders, age, left or right side of jaw, cortical bone thickness, mobility of mini-implants, and loading force.

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10 Keywords:Orthodontic anchorage, mini implants, Mini-screws, Self-tapping screw, Self-drilling screw/mini implant, Drill-free screws. Stability. Primary Stability. Mechanical Stability, Success Rate.

Abbreviations: Abbreviations are used in this systematic review to compare two different mini-implant systems are explained in following: Mini-mini-implant (MI), Numeric rates (NRS), Housefield unit scale (HU), and Periotest value (PTV)

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1. Introduction

Mini-implants (MIs) are small screw-like appliances used more broadly in alveolar bone or palatal bone to minimize surgical incision [1]. Modern dentistry has considerable orthodontic importance as defiance to undesirable tooth mobility [2]. Using this definition necessitate description of the reactive unit (tooth/teeth acting as anchorage during movement of the active unit) as well as the active unit (tooth/teeth undergoing movement). They can be placed in transosteal, subperiosteal, or endosteal; and they can be maintained on the bone either mechanically (cortically stabilized) or biochemically (osseointegrated) [3]. Unlikely the effectiveness of treatment relies on the

compliance of the patient, MIs have several advantages. First, the anatomic limitations for insertion are minimal and surgery is less traumatic. Second, immediate orthodontic loading is possible. Third, dental practitioners can place and remove them easily. [4]

Orthodontic MIs have been differentiated into self-drilling and self-tapping MIs by design, size, and shape of threads. Self-tapping MIs possess a tapered design and a blunt tip, and their threads are guided around a cylindrical core spiral. Self-tapping MIs require to place a pilot hole at the beneficiary site prior to application. [5] In contrast to the self-tapping MIs, self-drilling implants possess a sharper conical tip, inseparable single-piece design, and their treads are machined from the tip along an axis of rotation to the neck. Placing self-drilling MI is uncomplicated and consumes less time and thermal damage can be avoided. Moreover, there is less tendency of drill fracture. (Figure 1-2) [6] This system can improve primary stability through compressing bones when

implantation and contact surface of bone to implant is spacious. Thus, primary stability of self-drilling MIs is influenced by interproximal bony contact during application. Micro mobility of a MI is decreased suitable stability, which increases new bone formation. The self-drilling system is profitable with greater stability, especially in bone with lower density such as maxilla and adolescent patients. In higher density bone or thick cortical bone, however, the self-drilling system is not favorable in maintaining good primary stability by inducing excessive pressure that can cause micro fracture, adjacent cell damage, and other complications. [4]

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12 Furthermore, Kim et al reported that the main difference between two implants is self-drilling implants presented less mobility and more bone-to metal contact after application of forces of 200 to 300 g than screw-type implants applied after pilot drilling due to the pointed screw tip and cutting threads. In addition, MIs were distinguished by the influence of root contact on the stability of the implant by Son et al, and the self-drilling implants were reported significant higher mobility than the self-tapping implants. Implant stability should be correctly evaluated by using the survival or the success rate of the MI. However, MI mobility does not provoke the failure rate. Thus, MI stability should be precisely evaluated using the survival or success rate of the MI. The stability of MIs depends on partial osseointegration and mechanical retention in bone tissue [5]. These features not only allow the effective anchorage and the facility of insertion and removal of MIs but also carries a comparatively lower success rate comparing to the osseointegrated implants [6].

Moreover, self-drilling MIs have been described to rapid operative time, reduce bone damage and patient discomfort comparing to self-tapping MIs. As one of alternatives of surgical approach, orthodontic MIs can be conductive in copious situations: when patient compliance is an issue, when teeth are inadequate to captivate appropriate biomechanics, or when anchorage management is critical. [7] Tooth movement that has been deliberated beyond ordinary mechanotherapy

(asymmetric extrusions, bimaxillary protrusions, molar intrusions, distalization, mesialization, etc.) can be achieved with minimal patient cooperation with the use of MIs. Orthognathic surgery may not be necessary in open bite and bimaxillary protrusion cases. Patients may be considered with an option other than orthognathic surgery. [8]

The stability of MIs should always be the first concern to lead to orthodontic treatment success. In general, osseointegration of MIs is undesirable in consideration of facilitating its removal, and only a primary stability is pursued [9]. MIs can fail or success for various reasons as was found with dental implants. The causes of dental implant failure can include host factors (osteoporosis and uncontrolled diabetes, smoking and parafunctional habits), surgical factors of improper surgical technique and management factors. Although success rates varied, it was admitted that failure rates might be further reduced with increasing clinical experience and perfecting of the placement

technique. To conduct, few clinical studies have assessed MI success/failure rates, the predictability of placement techniques, or the management of risk factors for failure.

A systematic review was needed to evaluate the correlation between implant stability and its

success factors. Several individual clinical trials compared the success rates of the two types of MIs. Considering the diversity of methodology and results, a critical systematic review would be

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13 profitable. Thus, the research was managed to comprehensively evaluate, in an evidence-based way, the success rate and stability of self-drilling and self-tapping MIs in orthodontic procedures.

1.1 Aims of the research:

1. To compare self-drilling and self-tapping MIs in orthodontic practice and its influence on success rate;

2. Correlation between success rate and key factors in two different insertion techniques.

2. Materials and methods

The systemic review was guided in keeping with the protocol of the following PRISMA (Preferred Reporting Items for Systematic Review and Meta-analysis) statement. The systemic literature review is relied on selection of main information source as literature studies from electronic databases that were used during a search in Google web browser. Among 670 scientific publications in full articles, 9 clinical trials reviews were identified and related to keywords used during the research. Titles and abstracts derived from this broad research were individually selected to remove irrelevant publications. The homestretch of selecting involved reading the full texts to confirm each study’s eligibility based on inclusion and exclusion criteria. Our hypothesis focused inquiries were to evaluate the desirable root stability between self-tapping and self-drilling MIs and the key success factors of two MI systems. The following focused inquiry was established by the population, intervention, comparison, and outcome (PICOS) study design (Table 1).

Table 1. PICOS study design

Population Patients included in the clinical studies that were treated with MIs in orthodontics Intervention Factors to maintain the stability of MIs, MIs placed in alveolar bone

Comparison Comparison primary stability and success factors between self-tapping and self-drilling MI system

Outcome Relevant data on success rates of MIs and primary stability on two different implant systems

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2.1 Criteria for included studies

To be included in the study all records had to be determined by following inclusion criteria: 1) Trials with MIs; 2) In vitro studies; 3) Human studies.

1) Study design: randomized controlled trial, longitudinal (cohort study) and retrospective study; 2) Participants: patients undergo orthodontic treatment; 3) Intervention: the success and failure rate of self-drilling and self-tapping MIs as orthodontic anchorage was compared; 4) Outcome variables: the rate of success and failure of MI and primary stability of MI anchorage.

2.2 Criteria for excluded studies

The exclusion criteria were followed: 1) Literature review, case reports, single case reports, editorials, commercials, descriptive studies, conference abstract, and letters; 2) Ex vivo studies; 3) Animal experiment; 4) Subjects with systematic disease which influence on bone metabolism; 5) Other languages except English.

2.3 Search Strategy

The majority of studies chosen for this systematic review were published by 1) American Journal of Orthodontics and Dentofacial Orthopedics (http://www.ajodo.org/) 2) The Angle Orthodontist (http://www.angle.org/) 3) European Journal of Orthodontics (https://academic.oup.com/ejo/) 4) PubMed (https://www.ncbi.nlm.nih.gov/pubmed) 5) ScienceDirect

(https://www.sciencedirect.com/)and 6) Cochrane CENTRAL

(http://onlinelibrary.wiley.com/cochranelibrary/search). The search of the literature included

assessment of articles from dental journals and was published in the years from January 1st 2008 till 30th of September 2018 and included the keywords that were selected. Medical subjects’ headings (MeSH) terms were used to search “MIs”. Thus, the keywords that were used in the search are: “orthodontic anchorage”, “MIs”, “self-tapping screw”, “self-drilling screws” and “stability of implant”. Relevant literature has been available in full-text versions was determined whether to include it to the systemic study research.

2.4 Systemization and analysis of data

The analysis of the articles and data excerpt were performed according to the PRISMA flow

diagram (figure 3). The initial database search displayed 13 articles. The preliminary exclusion was completed by relevancy; 7 duplicated titles and abstracts were excluded. The number of studies

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15 included in qualitative research synthesis was 39. Then, 30 articles were excluded that were not randomized trials. At last, 9 articles were selected for the review. A flow chart of the selection process is presented in table 2.

Table 2. Search Flow Chart by databases

Steps Pubmed Selections

1 "Orthodontic" [Mesh] or "Orthodontic" [Text word] 65818

2

"MI" [MeSH] OR "MI" [Text Word] OR "MIs"[MeSH] OR "MIs" OR "Mini screw" [MeSH] OR "Mini screw" [Text word] OR "Mini screws [MeSH] OR "Mini screws"[Text

word] OR "Anchorage"[Text word] OR Success Rate [Text word] OR Primary Stability [Text word] OR Success Factor [Text word]

201

3 ("Self-drilling" OR "drill-free") AND ("self-tapping" OR "predrill" OR "drill" OR

"nondrill") 57

4 1 +2 + 3 combininig 4

5 4 limited to English and human 4

6 5 references hand search 0

7 5+6 Controlled trials 4

Steps CENTRAL Selections

2

MI" [MeSH] OR "MI" [Text Word] OR "MIs"[MeSH] OR "MIs" OR "Mini screw" [MeSH] OR "Mini screw" [Text word] OR "Mini screws [MeSH] OR "Mini screws"[Text word] OR "Anchorage"[Text word] OR Success Rate [Text word] OR Primary Stability [Text word]

OR Success Factor [Text word]

156

"nondrill") 27

Steps AJO-DO Selections

1 "Orthodontic" [Mesh] or "Orthodontic" [Text word] 1122 2 MI" [MeSH] OR "MI" [Text Word] OR "MIs"[MeSH] OR "MIs" OR "Mini screw" [MeSH]

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16 "Anchorage"[Text word] OR Success Rate [Text word] OR Primary Stability [Text word]

"nondrill") 383

Steps Science Direct Selections

2

MI" [MeSH] OR "MI" [Text Word] OR "MIs"[MeSH] OR "MIs" OR "Mini screw" [MeSH] OR "Mini screw" [Text word] OR "Mini screws [MeSH] OR "Mini screws"[Text word] OR "Anchorage"[Text word] OR Success Rate [Text word] OR Primary Stability [Text word]

30476

"nondrill") 1125

Overall 16

Dupulication 7

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17 E li gib il ity Studies included in qualitative synthesis (n=9) In clu d ed

Remove duplicated articles (n=7)

Filtered

Records excluded: Not relevant title and abstracts

(n=1)

Full-text articles assessed for eligibility

(n=16) Filtered S cr ee n in g Records screened (n=17)

Records screened after removing articles with other languages (n=17) Id en tif icat ion

Additional records identified by hand research (n=4) • • (n=13) Remove articles which were not written by English (n=5) Figure 3. PRISMA flow diagram

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18 The Cochrane hand book was applied to determine the quality of the studies admitted in the

systematic review. The succeeding features were analyzed as limited: 1) Sequence generation and concealed allocation, 2) size and composition of the studied groups, 3) blinding of participants, practitioners and investigators, 4) application of inclusion and exclusion criteria for subjects, 5) descriptions of loss to follow-up and 6) appropriacy of statistical analysis. Reviewer evaluated individual study, grading it as “adequate” when the relative item was evaluated to be held by a low risk of bias, “unclear” when insufficient information on the relative item did not concede evaluating the risk of bias, and “inadequate” when the corresponding item was evaluated to be related with high risk of bias. Sequence generation and concealed allocation were examined adequate when the group assignment was randomized and the clinician was blind to such assignment. Randomized participants, practitioners, and investigators were regarded as adequate when the investigator who analysed the results was slightly randomized on the condition of the subjects. However, randomized participants and practitioners were examined in orthodontic treatment. Use of inclusion and

exclusion criteria for subjects was viewed as suitable when they were correctly described prior to the inclusion of the subjects. Descriptions of loss to follow-up were deemed enough when

cancellation from the groups was certainly confirmed. Nevertheless, this evaluation was not relevant for cross-sectional studies, where loss to follow-up cannot occur. Sufficiency of statistical analysis was determined adequate when all contained subjects were analysed and statistical tests were evaluated relevant to the subjects. (Table 3)

2.5 Quality Assessment

The quality assessment of the included studies revealed an unknown risk of bias (for one of more key domains) for all of included studies

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3. Results

3.1. Search results

A total of 13 articles were first found by combining the key words and limited the studies to English and based on humans in PubMed, CENTRAL, AJO-DO and ScienceDirect. Thus, a total number of 9 controlled studies were included in the review. The quality assessment of the chosen studies indicated a high risk of bias in most of the articles for the reason that the relative items assessed were inadequate or the relevant items evaluated were inadequate, or because they were not described in brief. Broadly, the quality influences on progressing in the more recent trials with respect to the oldest, but also more modern studies obtained a very low-quality evaluation. [10-18]

3.2. Characteristics of included studies

The 9 articles included were from different countries. 4 articles were from Republic of Korea, 2 articles from Japan, the other articles from Taiwan, Iran and India. All articles were randomized controlled trials with orthodontic treatment in human and in vitro. Of the 9 studies included in the review, there were 4 longitudinal studies, 3 retrospective studies, 1 prospective study, and 1 in vitro study. [10-18].

Overall: 705 patients and 1454 MIs were studied in this systematic review. (Table 4)

In study of Chia-Chun Tsai et al., the distribution of the 254 MIs was in relation to patient age. The overall MI success rate was 85.8% (218/254) and the cumulative 1-year survival rate was 81.6%. Age and MI had the greatest effects on MI survival. MI survival was significantly longer in younger patients than in older patients (P=0.011). There was a significantly greater survival rate in the age 20-30 than the group older than 30 years. Also, the survival rate was significantly higher in patients with long MIs than in those with short MIs. [10]

Abbas Salehi examined in vivo study. The MI were designed for anchoring in orthodontic tooth movement. Among 57 patients, there are 49 women and 8 men. The effect of tapping and self-drilling orthodontic MIs was presented by inflammation and pain frequency. The observed pain score was between 0-7 based on numeric ratings from 0 as a value “Less” to 7 as a value “high” but this score is from 0-10. Many of results scored 1. Score 3 was reported by 30 MIs. As a result, only 8.8% of patients complained inflammation. The self-tapping and self-drilling orthodontic MI had scarce effect on inflammation accuracy. These was no significant difference on right and left

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self-20 tapping and self-drilling on inflammation analysis. There was significant difference on both sexes, ages, and correlation between mobility and inflammation. [11]

Hiroaki Iwai et al studied 80 patients with 142 MIs (diameter: 1.6 mm; length 8.0 mm). The success rate of self-drilling method was 91.5 % while of self-tapping method was 94.4% The self-drilling MIs tended to contact the distal tooth roots in the right side of the maxilla. In the self-drilling method, the failure rate was significantly higher in the root contact group than in the no-contact group. The success rate was not significantly different between two methods. Avoidance of root contact may improve the success rate in the self-drilling method than in the self-tapping method. [12]

Son et al. focused on success rate, placement torque, mobility, root contact frequency and the influence of root contact on mobility. The mobility was checked twice and continued for 6 months after placement. Force application was done using 200g for 6 months. The success rate of the MIs was approximately 96% for either placement technique. The respective success rates of male and female subjects were 95.9% and 95.2% in the drilling group and 96.0% and 95.0% in the self-tapping group. The success rates of the self-self-tapping and the self-drilling methods in the right side were 94.3% and 91.4%, respectively; the success rates in the left side were 97.1% and 100%. The placement torque values of both methods were 7 to 7.5Ncm, with no significant difference. The Periotest value present the stability and damping effect of the test object in a range from -8 to +50. As lower Periotest indicates higher in the stability of objects. The Periotest value of the self-drilling method was 3.8, and this value was significantly greater than that of the self-tapping method 1.4. Thus, self-tapping method is higher stability than the self-drilling. The rate of root contact on the right was 22.9% and that on the left was 17.1% with no significant difference between 2 methods. The Periotest value of the self-drilling MI with root contact 6.5 was significantly higher than that with no contact 3.1, while self-tapping MI with root contact was 1.5 and without root contact was 1.4. [13]

Seung-Hun Yoo 105 tapered and 122 cylindrical self-drilling MIs were placed into the maxillary and mandibular buccal alveolar areas of 132 patients (43 males and 89 females). The insertion torque and removal torque were measured and Periotest values were recorded at implantation. The success rates of the tapered and cylindrical MIs examined were similar. In the maxilla, the insertion torque of the tapered MIs (8.3 Ncm) was significantly higher than that of the cylindrical MIs (6.3 Ncm) (P˂0.05). The Periotest of the tapered MIs were statistically significantly lower in the maxilla

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21 (P˂0.05). The removal torque values showed no significant difference between the tapered and cylindrical MIs in the upper and lower buccal areas (P>0.05). [14]

Makoto Suzuki et al suggested that Root proximity of the MI can be a failure factor. According to result of 186 MIs in 105 consecutive patients, MIs placed near the roots had a significantly higher failure rate. Since the interradicular septum is narrow between the second premolar and the first molar in the mandible compared with the maxilla, MIs placed in the mandible tended to be closer to the root than were the maxillary MIs. When a MI is placed near the root, less osseous tissue is formed surrounding the MI; this results in increased mobility. Also, the contact between the MI and the root is observed during distalization of the entire arch, leading to increased mobility. A higher failure rate was observed when the distance between the MI and the neighboring root was within 1.4mm from the receiver operating characteristic curve analysis. Significantly higher insertion torque that exceeds 10 Ncm is observed with self-drilling MIs compared with self-tapping (9.2 Ncm). Clinically self-tapping is preferable for lower insertion torque with stable angulation of a pilot hole to improve the stability of the MI. In contrasts, self-drilling results in a higher torque value with an unstable drilling procedure that might be near the root. [9]

Nishant Gupta et al studied sample, which consisted of 20 patients requiring retraction of maxillary anterior teeth. The MIs were placed in the alveolar bone between maxillary 2nd_{premolar and 1st}

molar bilaterally at the junction of attached gingiva and movable mucosa. Pilot hole was drilled on the side which was selected for insertion of the self-tapping MI under copious irrigation, after which it was inserted. Self-drilling MI was inserted on the contralateral side without predrilling. All MIs were immediately load with 150-200 gm of retraction force. Patients revisit for follow up after 6 months. According to the mobility of MIs, Nishant Gupta et al. were considered to be a failure. Over 6 months, an overall success rate was 77.5%. 4 self-tapping and 5 self-drilling MIs failed during the study. [16]

Hoi-Jeong Lim, et al. studied 154 consecutive patients mean of age: 21.9 years with application of 378 MIs as orthodontic anchorage. Three types of MIs 1) predrilled type 2) drill-free and straight type 3) drill-free and tapered type. Potential confounding variables examined were age, sex, jaw (maxilla or mandible), placement site, tissue mobility (firm or movable tissue), type, length, and diameter of the MI, and the number of previous operations. The outcome variable of this study was initial stability, defined as the stability of the MI from placement to orthodontic force application. The overall success rate was 83.6% for all MIs (316 to 378). After adjusting for the type of MI, the relative success rate in the mandible was 0.48 times that in the maxilla but without statistical

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22 to initial stability. These results suggest that initial stability cannot be guaranteed or predicted. Thus, any treatment plan should consider the possibility of failure. [17]

Hyo-Sang Park et al. examined following 87 consecutive patients (35 males, 52 females; mean age was 15.5 year). 4 types of MIs (total 227) were used: 19 type A MIs (stryker Leibinger Inc,

Kalamazoo, Mich) (diameter, 1.2 mm; length, 5 mm); 157 type B MIs (Osteomed, Addison, Tex) (diameter, 1.2 mm; length, 6, 8, or 10 mm); 46 type C MIs (Absoanchor, Dentos, Daegu, Korea) (diameter, 1.2 mm; length, 4, 6, 7, 8, or 10 mm); 5 type D MIs (KLS-Martin, Jacksonville, Fla) (diameter, 2 mm; length, 10, 12, 14, or 15 mm). Success rates, during a 15-month period of force application were determined according to 18 clinical variables. The overall success rate was 91.6%. The clinical variables of MI factors (type, diameter, and length), local host factors (occlusogingival positioning) and management factors (angle of placement, onset, and method of force application, ligature wire extension, exposure of screw head and oral hygiene) did not show any statistical differences in success rates. General host factors (age, sex) had no statistical significance. Mobility, jaw (maxilla or mandible) and side of placement (right or left) and inflammatory shows significant difference in success rates. Mobility, the right side of the jaw and the mandible were the relative risk factors in the logistic regression analysis. When excluding mobility, inflammation around the screw implant was added to the risk factors. [18]

4. Discussion

The data were extracted from original articles showing several studies performed on this specific topic. To ensure that the most valid and reliable results were obtained, the articles were selected according to inclusion and exclusion criteria. After reviewing all published articles on MIs, 12 satisfied the inclusion criteria for articles with MIs as orthodontic anchorage. When the

methodological assessment was applied, most of these articles obtained medium-quality scores. As for dental implants, the key factors of success rate of two different MI systems are relevant to the primary stability as knowns as mechanical stability, root proximity, mobility of MI, and cortical bone thickness. (Table 3)

4.1. Success rate

The success rates of self-drilling and self-tapping MIs at temporary anchorage for orthodontic treatment was examined. The attained data were collected to investigate the overall success rates of two MI systems. The results of studies presented that the success rates did not differ between the

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23 two types of MI systems. But, depending on success/failure factors, the success rate can be

differentiated.

Researchers questioned what the success rates of self-drilling and self-tapping MIs in orthodontic treatment were. And the differences in success rates between self-drilling and self-tapping

orthodontic MIs. (Figure 4)

Chia-chun et al. states that survival analysis is used to investigate the relationship between specific medical therapy and survival rate (success rate) and be defined a MI failure as MI removal due to loosening, inflammation, or pathologic change in surrounding soft tissue. According to collected data from the results, all of success rates is nearly over 90%. The minimum value from the data was 77.5%. The overall MI success rate was 85.8% (218 of 254 MIs), and the cumulative 1-year

survival rate was 81.6% in study of Chia-chun et al. [10]

Hyo-Sang Park reported that the overall success rate was 91.6% for all MIs with a mean period of force application of 15 months. [18]

4.2. Gender

Chia-chun et al found that there is no significant difference in success rate. [10] Overall Success Rate Success Rate of Self-Tapping Success Rate of Self-Drilling Success Rate by insertion location Success Rate by Genders 0.00% 10.00% 20.00% 30.00% 40.00% 50.00% 60.00% 70.00% 80.00% 90.00% 100.00%

Success rate of mini-implants

Chia-Chun Tsai et al. Abbas Salehi Vaziri et al. Hiroaki Iwai et al.

Seil Son et al. Seung-Hun Yoo et al. Makoto Suzuki et al.

Nishant Gupta et al. Hoi-Jeong Lim et al. Hyo-Sang Park et al.

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24 Hoi-Jeong et al states that there was difference in success rate in gender. Female had a higher success rate (85.7%) than the males (79.4%). [17]

Hyo-Sang Park et al reported that there were no significant differences according to gender. [18]

4.3. Age

Chia-chun et al described that the most important factor in MI outcome is patient age, which was positively associated with MI failure risk. In article, the age was divided into 3 groups (under 20 years, From 20 to 30, and above 30 years old). Log-rank test presented a significant higher survival rate in the age group 20-30 years than in the age above 30 years (P<0.05). Survival rates of MIs was significantly loner in younger patients than in elders. (P=0.011). Another important factor was MI length. [10] Hoi-Jeong Lim states that the success rate was higher in a no statistically significant trend. Because they found that children have a high possibility of loosening. [17] Hyo-Sang Park reported that there was no significant difference in age. [18]

4.4. Pain frequency

According to data by Abbas et al, the observed pain score was between 0-7 based on numeric rates. Patients were asked to indicate the intensity of pain by reporting a number that best represented it. The NRS is easy to administer verbally in a clinical setting and is a familiar clinical tool. Also, the visual analog scale has been used extensively in clinical research. MIs fail for numerous causes. The reasons of dental implant failure are host aspects (osteoporosis, diabetes, smoking), surgical factors of improper surgical method. Surgical factors include improper surgical techniques such like lack of initial stability, overheating during placement, and the fitness of pilot hole to the diameter of the MI. In modern study, all MIs were placed by same dentist by using similar technique, thus there are no effect on the clinical success on the surgical factors. Patient reacted under pain score. The most score 1 to score 3 were reported by 30 MIs. According to results, the inflammation was diagnosed only in 8.8% of patients. The self-tapping and self-drilling orthodontic MIs had scarce effect on inflammation accuracy. Hyo-Sang Park reported that screw implants with inflammation showed significantly less success. [18]

4.5. Shape of MIs

Seung-Hun Yoo reported that overall success rates were 82.9 and 80.3% for the tapered and

cylindrical MIs. There was no significant difference in the success rates between the cylindrical and tapered MIs. [14]

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25

4.6. Length and diameter of MIs

In study of Hoi-Jeong Lim, there were comparison in six different diameters; 1.2, 1.6, 1.8 mm and lengths of MIs; 6, 7, 8, 9, 10, 12 mm. They were not significantly associated with stability. [17]

4.7. Left or right MI on inflammation

There was no significant difference of whether the inflammation was noticed on the right or left side of the jaw. The difference was not significant p=0.7 There was significant difference on pain between both sexes p=0.03. Makoto Suzuki et al found no significant difference between the right and left sides in both jaws. [15] Hyo-Sang Park found that the left side had significantly higher success than the right side. [18]

4.8. Cortical bone thickness

Motoyoshi demonstrated that placement torque is influenced by the cortical bone thickness and quality, and reported that placement torque should be larger for stiff cortical bone. On the other hand, Tachibana et al. reported that both the self-tapping and the self-drilling placement methods were safe without visible bone damage or screw facture when the MIs were inserted into thin cortical bone areas such as maxillary alveolar bone; toque values were within the recommended range from 5 to 10 N cm for both methods, according to Motoyoshi et al. Placement torque of the self-tapping method was 7 N cm and that of the self-drilling method was 7.5 N cm (P>0.05); both torque values were within the recommended range. These torque values might have participated to the increased success rates of both methods in the maxilla. The right side with either method had a lower success rate than did the left side, but the right and left side differences were not significant. [19-20] Son et al. also presents that the placement torque values of both methods; self-drilling and self-tapping were 7 to 7.5Ncm, with no significant difference. The success rates was not

significantly different between the self-drilling and the self-tapping methods in the maxilla. The success rates of the MIs were 91.5% for the self-drilling method and 94.4% for the self-tapping method (P>0.05). The self-drilling MIs tended to contact the distal teeth roots in the right maxilla. In the self-drilling method, the failure rate was significantly higher in the root contact group than in the no-contact group (P<0.05). [13]

Makoto Suzuki found that the average bone density values surrounding the MIs were 987.6 and 917.4 HU in the maxilla and the mandible. There was no significant difference in the bone density between any analyzed variables. [15]

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26

4.9. Rate of root contact

Iwai et al and Seil Son et al investigated the root contact of self-drilling and self-tapping MIs. There was no difference in the rate of root contact between 2 types of anchorage system. In addition, Hiroaki found that the rates of adjacent tooth root contact were 21.1% in the self-drilling method and 19.7% in the self-tapping method, with no significant difference. The rates of root contact were 22.9% on the right side and 18.1% on the left side, with no significant difference. A significant difference was observed between the distal and mesial sites in the right maxilla with the self-drilling method, and the self-drilling MIs tended to contact the distal tooth root (P<0.01) the failure rate was significantly her in the contact group than in the no-contact group (P<0.05) However, Iwai et al found self-drilling implants tended to contact with distal roots with significance, especially at right maxilla. [12-13] Seung-Hun Yoo reported that the distal area of the first molar had significant low success rate than other insertion sites. However, site of insertion has no significant differences in success rate. [14] According to study of Hoi-Jeong et al, the insertion location, MIs in the maxilla had a 10% higher success rate than those in mandibular. [17] Hyo-Sang Park et al found that implants placed in the maxilla showed a significantly higher success rate than those placed in the mandible. [18]

4.10. Mobility of MIs

Seil Son et al compared the mobility of MIs contacting tooth roots and observed that self-drilling MIs indicated extremely higher mobility than self-tapping MIs. A MI was considered successful when it endured an orthodontic force applied for 6 months or more without clinical mobility. [13] Abbas et al found that Significant correlation has observed between mobility and inflammation. (p =0.022). [11] Nishant Gupta states that the major failure factor was mobility of the MI. There was no significant difference found (p=1.00) on success/failure rate on self-tapping and self-drilling systems. However, 7/9 MIs were attributed to mobility. There was no statistically significant difference with respect to mobility on both. (P=0.667). MIs are used as temporary ﬁxtures for orthodontic tooth movement and are removed once the treatment is over. It seems however, that MIs as temporary ﬁxtures do not have to remain absolutely stationary unlike endosseous implants throughout orthodontic loading as long as the treatment objectives are achieved. [16] In study of Hyo-Sang Park et al, screw implants with mobility showed significantly less success than those without mobility. [18]

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27 Son el al presented that the shortest screw-root distance was significantly less in the self-drilling method (p<0.05) In the horizontal cross section, the angle of the screw was more perpendicular to the bone surface in the self-drilling method (p<0.05). In the vertical cross section, the angle tended to be more inclined in the self-tapping method (p<0.05). [13] Seung Hun Yoo studied that there was no significant difference in insertion torque values between the success group and failure group on buccal side of the mandible. There was no significant difference. On the buccal side of the

mandible, the insertion torque of the tapered MIs (9.2 Ncm) was higher than the cylindrical MIs (7.8 Ncm), but this finding was not statistically significant (P > 0.05) [14]

Makoto Suzuki showed that there was no significant difference in the success rates between the torque value in both jaws. However, there was a tendency that with higher torque value, the success rate was lower. [15]

Study of Seung-Hun Yoo stated that MI with low insertion torque values (below 3 Ncm) had a significantly lower success rate than those in the maxilla. However, the Periotest value categories showed statistical significance in success rate. Logistic regression analysis did not detect any variables affecting the MI success rates. No correlation was found between the insertion and removal torques in both: maxilla and mandible (P>0.05). However, a correlation was detected between insertion and removal PTVs in the maxilla (P<0.01) [14] In study of Makoto, lower torque value was used in maxilla which has lower density with value under 5 Ncm. Applying lower torque can be the limitation of this study but the smaller MIs, used in Makoto’s study. So, it has a tendency for increasing the torque value for longer and for mandibular MI. Since the maxilla has low density, the insertion torque tends to be low with better stability. Makoto suggests to perform with torque value 5-10 N cm. [15]

4.12. Limitations

Although this systematic review was carried out carefully following normalized process, some limitations still exist which deserved further discussion. First, large number of original studies was recruited and the study designs included longitudinal, retrospective and prospective, high-quality original studies. As this study is systematic review, range of relevant data is broad.

According to data by Abbas et al, the reasons of dental implant failure are host aspects

(osteoporosis, diabetes, smoking), surgical factors of improper surgical method. Surgical factors include improper surgical techniques like lack of initial stability, overheating during placement, and

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28 the fitness of pilot hole to the diameter of the MI. In modern study, all MIs were placed by the same clinician by using similar technique.

5. Conclusion

Anchorage control is the most important concept in successful orthodontic treatment. Traditional techniques, such as use of multi-bracket appliance, extra oral anchorage by headgear and functional therapies, cannot effectively control anchorage, especially in adult patients. The reinforcement of anchorage requires complicated biomechanics and good patient compliance. Application of the MIs as alternative anchorage for various types of tooth movement has been acknowledged [4] The success rates of self-drilling and self-tapping MIs are similar in short term and long-term use at the maxillary buccal area. Determining the position and direction of placement should be more precise when self-drilling MIs are inserted into site with narrow root proximity.

1. The self-tapping method is useful against the self-drilling method in maxillary alveolar bone because both placement techniques had high success rates. Self-drilling MIs showed greater mobility than did the self-tapping MIs, although this difference did not influence the success rate of the self-drilling method. Special attention to root proximity is recommended because MIs with root contact had significantly greater mobility when placed with the self-drilling method compared with the self-tapping method. With self-tapping MIs, root contact can be overlooked because it did not affect the high mobility in the self-tapping group. Tapered and cylindrical MIs were similar and there was no significant difference in success rates according to gender, jaw, and side of insertion.

2. Stability and success rate of MIs can be affected by various factors such as insertion torque, individual anatomical variation, and insertion site. When use of 1.3 mm diameter MI as

anchorage, the successful minimum lengths are 5mm in the maxilla and 6 mm in the mandible. Approximately 3.8mm of total length of the MI in bone for MI stability is approximately 3.8mm. Root proximity rather than bone density is the major factor in MI failure. A higher failure rate was observed for MI less than 1.4 mm long and replacement of the MI by changing the site or the angulation is recommended, especially in the mandible. There was a tendency for a higher failure rate with increased insertion torque, and all MIs were stable if the insertion torque was within the range of 5 to 10 Ncm however the ideal torque value might be differentiated by the placement method.

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29 Both self-tapping and the self-drilling MIs are effective anchorage units. Nevertheless, self-tapping MIs are still recommended for areas with high bone density and thick cortical bone where self-drilling MIs are not useful. Both techniques are beneficial to use as alternative one another.

However, this systematic review presents that initial stability cannot be guaranteed or predicted. All of data chart showed different results on genders, age, left or right side of jaws, cortical bone

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30

6. References

[1] Herman R, Cope J. Temporary anchorage devices in orthodontics: MIs. Semin Orthod. 2005;11:32–9.

[2] Daskalogiannakis J, author. Glossary of Orthodontic Terms. Leipzig: Quintessence Publishing Co. 2000: p. 27

[3] Ottoni JM, Oliveira ZF, Mansini R, Cabral AM. Correlation between placement torque and survival of single-tooth implants. Int J Oral Maxillofac Implants. 2005;20:769–76.

[4] Tseng YC, Hsieh CH, Chen CH, Shen YS, Huang IY, Chen CM. The application of MIs for orthodontic anchorage. Int J Oral Maxillofac Surg. 2006; 35:704–707. URL:

https://www.ncbi.nlm.nih.gov/pubmed/16690253

[5] Kim JW, Ahn SJ, Chang YI. Histomorphometric and mechanical analyses of the drill-free screw as orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2005; 128:190–194. URL:

https://www.sciencedirect.com/science/article/pii/S0889540605001459

[6] Miyawaki S, Koyama I, Inoue M, Mishima K, Sugahara T, Takano-Yamamoto T. Factors associated with the stability of titanium screws placed in the posterior region for orthodontic anchorage. Am J OrthodDentofacOrthop. 2003; 124:373–8. 5. URL:

[7] Heidemann W, Terheyden H, Louis Gerlach K. Analysis of the osseous/metal interface of drill free screws and self-tapping screws. Journal of Cranio-Maxillofacial Surgery. 2001;29(2):69–74. URL: https://www.sciencedirect.com/science/article/pii/S1010518200901793

[8] Grabar, Vanarsdall, Vig, Huang. Orthodontics Current Principles and Techniques. Mosby; 2016. p. 40-43

[9] Petrey JS, Saunders MM, Kluemper GT, Cunningham LL, Beeman CS. Temporary anchorage device insertion variables: effects on retention. Angle Orthod. 2010; 80:446–53. URL:

http://www.angle.org/doi/pdf/10.2319/070309-376.1?code=angf-site

[10] Chia-Chun Tsai, Hong-Po Chang, Chin-Yun Pan, Szu-Ting Chou and Yu-Chuan Tseng, A prospective study of factors associated with orthodontic MI survival, Journal of Oral Science, 58, 4, (515) URL:https://www.jstage.jst.go.jp/article/josnusd/58/4/58_16-0145/_article

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31 [11] Abbas Salehi Vaziri et al. The clinical success of self-tapping and self-drilling orthodontic miniscrews. Research Trend, 2015;7(2): 133-137 URL:

http://www.researchtrend.net/bfij/pdf/22%20HAMED%20NASERI.pdf

[12] Iwai, H., Motoyoshi, M., Uchida, Y., Matsuoka, M. and Shimizu, N. (2015) Effects of tooth root contact on the stability of orthodontic anchor screws in the maxilla: comparison between self-drilling and self-tapping methods. American Journal of Orthodontics and Dentofacial Orthopedics, 147, 483–491. URL: https://www.sciencedirect.com/science/article/pii/S0889540614011627 [13] Seil Son, et al. Comparative study of the primary stability of self-drilling and self-tapping orthodontic miniscrews. AJO-DO, 2014;145:480-5. URL:

[14] Seong-Hun Yoo, Young-Chel Park, Chung-Ju Hwang, Ji-Young Kim, Eun-Hee Choi, Jung-Yul Cha; A comparison of tapered and cylindrical miniscrew stability, European Journal of Orthodontics, Volume 36, Issue 5, 1 October 2014, Pages 557–562, URL:

https://academic.oup.com/ejo/article/36/5/557/405479

[15] Suzuki, Makoto & Deguchi, Toru & Watanabe, Hisako & Seiryu, Masahiro & Iikubo,

Masahiro & Sasano, Takashi & Fujiyama, Koji & Takano-Yamamoto, Teruko. (2013). Evaluation of optimal length and insertion torque for miniscrews. American journal of orthodontics and dentofacial orthopedics: official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics. 144. 251-9. URL:

https://www.ncbi.nlm.nih.gov/pubmed/23910206

[16] Nishant Gupta. A Comparative Clinical Study Between Self Tapping and Drill Free Screws as A Source of Rigid Orthodontic Anchorage. J Maxillofac Oral Surg. 2012 Mar, 11(1): 29-33. URL: https://link.springer.com/article/10.1007%2Fs12663-011-0240-y

[17] Hoi-Jeong Lim, Chun-Sun Eun, Jin-Hyoung Cho, Ki-Heon Lee, Hyeon-Shik Hwang, Factors associated with initial stability of miniscrews for orthodontic treatment, American Journal of Orthodontics and Dentofacial Orthopedics, Volume 136, Issue 2, 2009, Pages 236-242, URL: https://www.sciencedirect.com/science/article/pii/S0889540609003461

[18] Hyo-Sang Park, Seong-Hwa Jeong, Oh-Won Kwon, Factors affecting the clinical success of screw implants used as orthodontic anchorage, American Journal of Orthodontics and Dentofacial

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32 Orthopedics, Volume 130, Issue 1, 2006, Pages 18-25. URL:

[19] Motoyoshi M, Hirabayashi M, Uemura M, Shimizu N. Recommended placement torque when tightening an orthodontic MI. Clin Oral Implants Res 2006; 17:109-14. URL:

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1600-0501.2005.01211.x

[20] Tachibana R, Motoyoshi M, Shinohara A, Shigeeda T, Shimizu N. Safe placement techniques for self-drilling orthodontic MIs. Int J Oral Maxillofac Surg. 2012; 41:1439-44. URL:

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