The Comparison of Class II Malocclusion Treatment Outcomes between Maxillary Premolars Extraction and Functional Appliance Associated with Fixed Appliance

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Rand Bahro

5th_{year, group 13}

The Comparison of Class II Malocclusion Treatment

Outcomes between Maxillary Premolars Extraction and

Functional Appliance Associated with Fixed Appliance

Master's thesis

Supervisor D.D.S, PhD, Prof. Arunas Vasiliauskas

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LITHUANIAN UNIVERSITY OF HEALTH SCIENCES MEDICAL ACADEMY

FACULTY OF ODONTOLOGY CLINIC OF ORTHODONTICS

The Comparison of Class II Malocclusion Treatment Outcomes between Maxillary Premolars Extraction and

Functional Appliance Associated with Fixed Appliance Master's thesis

The thesis was done

by student ... Supervisor ... (signature) (signature)

... ... (name surname, year, group) (degree, name surname)

29/04/2020 29/04/2020

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

Evaluation: ... Reviewer: ... (PhD Arunas vasiliauskas) Reviewing date: ... Compliance with MT

No. MT parts MT evaluation aspects requirements and

evaluation Yes Partially No 1

Summary (0.5 point)

Is the 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, ai,m, 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?

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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?

0.4 0.2 0

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

0.4 0.2 0

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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

Systemization 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

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summary data for each intervention group; b) effect estimates and confidence intervals)

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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

27 Is the scientific level of references suitable for

Master's thesis? 0.2 0.1 0

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 recommendations

Are the practical recommendations suggested

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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 requirements

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?

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

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43

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

*In total (maximum 10 points):

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

Reviewer’s comments: ___________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ __________________________________________________________________________

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SUMMARY

Relevance and Aim: Various methods are available for Class II malocclusion treatment but they might have different effects on the craniofacial structures. Aim is to compare skeletal, dental, and soft tissue outcomes of maxillary premolars extraction (PE) treatment and functional appliance associated with fixed appliance (FAF) treatment in Class II patients by evaluating results of cephalometric analysis.

Materials and Methods: Electronic search was conducted in PubMed, Cochrane Library, Web of Science, and Science Direct databases up to January 2021 using the keywords "Class II

malocclusion", "functional appliance", "premolar extraction", "cephalometric". Randomized controlled trials, prospective and retrospective studies including adolescents with skeletal Class II malocclusion, retruded mandible and increased overjet and reporting cephalometric changes after PE or FAF treatments published within 10 years were included.

Results: After examining 953 article abstracts, full text of 63 articles was read and assessed for eligibility. Four studies that fulfilled the inclusion criteria were included in the review. Studies reported approximately similar effects and ranges of change in skeletal, soft tissue, and most dental cephalometric variables after both treatments, but changes in 1-NA°(PE: -0.36°(SD 7.82) to -2.47°; FAF: -1.66°(SD 9.75) to -6.88°(SD 4.15)), and 1-NB°(PE: 2°(SD 5.13) to 3.5°; FAF: 5.13°(SD 8.65) to 6.07°(SD 4.86)) and IMPA were more pronounced in functional appliances associated with fixed appliance treatment.

Conclusion: There is no clinically significant difference between skeletal and soft tissue outcomes of both treatment methods. However,functional appliance associated with fixed appliance caused more maxillary incisors retroclination and mandibular incisors proclination than maxillary

premolars extraction treatment.

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10

INTRODUCTION

Class II malocclusion is one of the most predominant malocclusions encountered in the clinical dental practice and the second most prevalent malocclusion globally. Among all continents, Europe had the highest prevalence of Class II malocclusions [1,2].

The etiology of Class II malocclusion is multifactorial. Polygenic mode of inheritance has been attributed to the formation of the malocclusion. Moreover, parafunctions such as nasal blockage, incompetent lips, and finger sucking can lead to mandibular clockwise rotation, resulting in Class II malocclusion[3]. This malocclusion is often associated with increased dental injury incidence, masticatory function disturbances, decreased facial esthetics and attractiveness, and decreased quality of life [4–6].

Various Class II malocclusion treatment approaches including headgear, removable functional appliances, fixed functional appliances, extraction, molars distalization, and orthognathic surgery are now available for orthodontists[7]. However, these different therapeutic techniques might affect the craniofacial structures differently.

The treatment of Class II malocclusion in growing patients should ideally aim to fix the skeletal discrepancy. The proposal that functional appliances affect jaw growth is alluring for both

clinicians and patients; therefore, functional appliances are often the treatment of choice for patients with retrognathic mandible[8,9]. However, evidence that significant jaw growth occurs due to functional appliance treatment is limited [9]. Authors that investigated the effects of functional appliances concluded that these appliances effectively treat Class II malocclusion, but the main effects were dental rather than skeletal[10,11].

Maxillary premolars extraction is an alternative approach for treating Class II malocclusion that tends to camouflage the underlying sagittal discrepancy [7]. Soft tissue profile had the most significant impact on the orthodontists’ decision to extract[12]. A primary concern regarding extraction treatment is that it has been suggested that extraction causes great retrusion of lips and result in a flat profile[13]. Extraction as a part of orthodontics treatment has been a subject of debate for many years, and controversies remain about its effects. Recent studies had inconsistent findings. Verma et al[14] found that extraction treatment resulted in more lips retrusion than non-extraction treatment, while Kirschneck et al [15]inferred that lips retrusion in the non-extraction group is clinically irrelevant.

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11 Functional appliances associated with fixed appliance and maxillary premolars extraction both have the same goal of treating Class II malocclusion, but might have different effects on the skeletal, dental, and soft tissues; thus, a thorough understanding and comparison of the outcomes of both treatments are required to be able to choose an appropriate treatment plan for each patient.Only one recent systematic review comparing extraction versus non-extraction treatment was identified; however, it considered different malocclusion classes and assessed only soft tissue changes[16]. No reviews comparing premolars extraction treatment to functional appliances associated with fixed appliance non-extraction treatment in Class II patients and assessing their skeletal, dental, and soft tissue effects have been conducted.

Aim:

To compare skeletal, dental, and soft tissue outcomes of maxillary premolars extraction treatment and functional appliance associated with fixed appliance non-extraction treatment in Class II patients by evaluating results of cephalometric analysis.

Objectives:

1-To compare skeletal outcomes of Class II patients after maxillary premolars extraction treatment and functional appliance associated with fixed appliance treatment by evaluating cephalometric changes.

2-To compare dental outcomes of Class II patients after maxillary premolars extraction treatment and functional appliance associated with fixed appliance treatment by evaluating cephalometric changes.

3-To compare soft tissue outcomes of Class II patients after maxillary premolars extraction treatment and functional appliance associated with fixed appliance treatment by evaluating cephalometric changes.

Hypothesis:

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12

ABBREVIATIONS

E-line: esthetic line of Ricketts /line from pronasale - pogonion RCT: randomized controlled trial

MBT brackets: brackets designed by McLaughlin, Bennett, and Trevesi FFA: fixed functional appliance

FAF: functional appliance associated with fixed appliance FRD: Forsus Fatigue Resistant device

JJ: jasper jumper

MARA: mandibular anterior repositioning appliance TFBC: twin force bite corrector

PE: premolars extraction SD: standard deviation m: male

f: female

JBI: Joanna Briggs Institute n: number S: sella N: nasion A: subspinal B: supramental Go: gonion Gn: gnathion U1: upper incisor L1: lower incisor Prn: pronasale

Pgs: soft tissue pogonion Cm: columella

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DESCRIPTION OF CEPHALOMETRIC FIGURES

Skeletal cephalometric variables are demonstrated in Fig.1

1. SNA: angle between lines SN and NA/ indicate anterior -posterior position of the maxilla 2. SNB: angle between lines SN and NB/ indicate anterior -posterior position of the mandible 3. ANB: angle between lines NA and NB/ indicate sagittal discrepancy between maxilla and

mandible

4. SN-GoGn: angle between SN and GoGn / skull base to mandibular plane angle 5. Co-Gn: line from condylon to gnathion / indicate mandibular length

Fig. 1. Skeletal cephalometric variables [17]

Dental cephalometric variables are demonstrated in Fig.2

1. 1-NA degree: angle between long axis of maxillary central incisor and NA line. 2. 1-NA mm: distance between anterior point of maxillary central incisor and NA line. 3. 1-NB degree: angle between long axis of mandibular central incisor and NB line. 4. 1-NB mm: distance between anterior point of mandibular central incisor and NB line. 5. IMPA: angle between long axis of mandibular central incisor and mandibular plane.

6. Overjet: distance between incisal edges of maxillary and mandibular central incisors parallel to occlusal plane

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14 Fig. 2 .Dental cephalometric variables [18,19]

Soft tissue cephalometric variables are displayed in Fig.3

1. NLA: nasolabial angle formed by lines Cm-Sn and Sn-UL 2. UL-E line.: distance from upper lip to E line

3. LL-E line: distance from lower lip to E line

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15

1. SELECTION CRITERIA OF THE STUDIES. SEARCH METHODS AND

STRATEGY

Bioethics approval number: BEC-OF-117

1.1 Protocol

This systematic review was conducted in compliance with the PRISMA ( Preferred Reporting Items for Systematic Reviews and Meta-Analyses ) requirements[21].

1.2 Focus Question

The focus question was formulated according to PICOS (Population, Intervention, Comparison, Outcome, Study design) and presented in Table 1[21].

Table 1. PICOS

Components Description

Population Growing patients with skeletal Class II malocclusion , retrognathic mandible and increased overjet.

Intervention Maxillary premolars extraction followed by fixed appliance treatment

Comparison Functional appliances associated with fixed appliance treatment

Outcome Skeletal, dental, and soft tissue cephalometric changes

Study design Randomized control trials, prospective studies, or retrospective studies

Focus Question Do premolars extraction treatment and functional appliance associated with fixed appliance treatment of Class II patients have different skeletal, dental, and soft tissue outcomes?

1.3 Information Sources

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16 1.4 Search

PubMed, Cochrane Library, Web of Science, Science Direct databases, and other electronic journals were thoroughly searched using different combinations of the keywords: “Class II

malocclusion”, “cephalometric” or “cephalometric analysis”, “functional appliances” and “premolar extraction”. The keyword combinations searched in each database are represented in Table 2. Table 2 . Search strategy

1.5 Types of Publications

Only clinical research articles were considered in this review. Database Search

date Key words Results

PubMed January 28, 2021

((("class ii malocclusion"[All Fields]) AND ("cephalometric"[All Fields])) AND ("functional appliance"[All Fields])) OR ((("class ii

malocclusion"[All Fields]) AND ("cephalometric"[All Fields])) AND ("premolar extraction"[All Fields]))

85

Cochrane library

January 31, 2021

((class II malocclusion AND cephalometric* AND functional appliance)) OR (( class II malocclusion AND "premolar extraction"

AND cephalometr* ))" (Word variations have been searched) 87

Web of science

January 30, 2021

TOPIC: ((premolar extraction) AND (cephalometric) AND (class II malocclusion)) OR TOPIC: ((class II

malocclusion) AND (cephalometric) AND (functional appliance)) In all databases 361 Science direct January 30, 2021

(" class II malocclusion" AND "premolar extraction " AND "cephalometric analysis" ) OR (" class II malocclusion" AND "

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17 1.6 Types of Studies

Selected articles were randomized controlled trials, prospective, and retrospective studies published between 2010 and 2020.

1.7 Population

Growing patients with skeletal Class II malocclusion, retrognathic mandible, and increased overjet undergoing either premolars extraction treatment or functional appliances associated with fixed appliance treatment were considered.

1.8 Eligibility criteria The inclusion criteria:

- Human studies

- Skeletal Class II patients with increased overjet and retrognathic mandible. - Growing patients (mean age at the beginning of the treatment is between 9-17).

- Studies comparing maxillary premolars extraction and functional appliances associated with fixed appliance treatments or having at least one intervention group treated with either methods.

- Studies that evaluated skeletal, dental, or soft tissue cephalometric changes using similar cephalometric variables

- Studies that provided cephalometric pretreatment, posttreatment, and treatment change values.

- Randomized controlled trials, prospective or retrospective studies - Studies published between 2010- 2020

- The study's original language is English or is translated to English. Exclusion criteria:

- Nonhuman subjects

- Invitro studies, case studies, case reports

- Patients with craniofacial anomalies and syndromes - Studies done on adults.

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18 1.9 Selection of Studies

After duplicates elimination, titles and abstracts of initially identified articles according to the keywords were screened. Case reports, nonhuman studies, and other irrelevant articles which did not match our topic were eliminated. Subsequently, the remaining articles' full texts were retrieved and read carefully. Their results were screened to find the most commonly used skeletal, dental, and soft tissue cephalometric variables. A list of cephalometric points to be assessed was then created; Subsequently, articles that did not use similar variables were eliminated. Only human studies which considered cephalometric changes after maxillary premolars extraction treatment and/or functional appliances associated with fixed appliances that met all the inclusion criteria were included. 1.10 Data extraction:

Only data concerning the clinical group of interest from each included article were extracted. Data about authors name, year of publication, type of study, sample size, patients' age, intervention, treatment duration, outcomes of interest, pretreatment cephalometric values, posttreatment

cephalometric values of the assessed variables, and treatment change were collected and arranged in fields. When the same cephalometric variable was given different abbreviations in studies, one abbreviation was chosen and applied.

1.11 Risk of Bias within studies

For evaluating bias within studies, two Joanna Briggs Institute (JBI) critical appraisal checklists were used.JBI critical appraisal checklist for randomized controlled trials, consisting of 13 questions, was used to evaluate included RCTS; while JBI critical appraisal checklist for quasi-experimental studies consisting of 9 questions was used to evaluate prospective and retrospective studies (Annex 1). The questions assessed specific aspects of studies to determine their

methodological quality. Each question could be answered by "yes", "No", "unclear" and "Not Applicable"[22]. Later the percentage of questions answered by "yes" was calculated.

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2- SYSTEMATIZATION AND ANALYSIS OF DATA

2.1 Study selection

In total, 953 scientific publications were found related to the keywords specified. After duplicates were removed, 652 articles' abstracts were screened, and irrelevant publications were eliminated. Full text of 63 articles that appeared to have met the initial inclusion criteria or lacked sufficient data for exclusion was retrieved and read carefully for the final assessment of eligibility. 17 articles were excluded because there was no fixed orthodontic treatment associated with functional

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20 Fig .4. Prisma Flow Chart

Id enti fi ca ti on S cree ning E li gi b il it y Inc lude d

Records identified through database searching (n=945) PubMed: (n=85) Cochrane library: (n=87) Web of Science: (n=361) Science Direct: (n=412) Records screened for relevance (n=652)

Additional records identified through other sources

(n= 8)

Records after duplicates removed (n=652)

Studies included

(n=4)

Full text articles excluded

(n=59) -No associated fixed

appliance treatment (n=17) -Cephalometric variables do not match

(n=15) -Missing data (n=7) -Ineligible population

(n=13) -Other reasons (n=8) Full text articles assessed

for eligibility (n=63)

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21 2.2 Study characteristics

Data about study design, sample size, age of patients at the beginning of treatment, treatment

method, duration, and outcomes of the included studies were recorded and demonstrated in Table 3. All the studies took place at university hospitals. They included 119 patients (PE: 59 patients; FAF: 60 patients); mean age between (12.11 years (SD 1.36) to 14.03 years (SD 2.65)). One study reported maxillary PE effects [24], two studies reported FAF effects[26,27] and Only one study directly compared PE to FAF treatment[25]. All studies reported skeletal, dental, and soft tissue analysis data except Guimaraes et al[27] study which did not report soft tissue effects.

Seben et al’s[24] study included patients who had at least ½ Class II molar relationship. They were treated with two premolars extraction followed by edgewise braces. Headgear and/or Class II elastics were used for anchorage.

Janson et al[25] compared both treatments. Included patients had at least ¾ Class II molar

relationship bilaterally. For the two PE group, extraoral headgear or extraoral headgear associated with Class II intermaxillary elastics were used for anchorage. In the FAF group, jasper jumper or Forsus appliances were inserted after initial leveling and alignment with brackets. However, in patients who used MARA, the appliance was applied first followed by brackets. Appliances were utilized until Class I molar and canine relationship was achieved; later, Class II elastics were used for retention. Active treatment time for JJ appliance was (0.65 years), MARA (0.85 years), and Forsus (0.33 years).

In Eissa et al's [26]study, MBT brackets were bonded to all teeth except canines in which Damon 3MX brackets were applied . After leveling and alignment FRD was inserted. Active treatment duration was (6.06 months (SD 0.76)), but overall treatment duration was not reported. In

Guimaraes et al' s[27] study TFBC was inserted after initial alignment and leveling with fixed Roth preadjusted braces. The mean active treatment duration was (0.24 years). In both studies

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22 Table 3. Study characteristics

Author, year of publication Study Design Sample size Gender Initial age (Mean (SD)) years Intervention Duration of treatment (mean (SD)) years Outcomes Seben et al 2013 [24] retrospective 34 m:19 f:15 14.03 (2.65) 2 maxillary premolars extraction+ edgewise technique brackets 3.21 (1.43) skeletal, dental, soft tissue Janson et al 2018 [25] retrospective 25 m:10 f: 15 13.05 (0.9) 2 maxillary premolars extraction + brackets 2.69 (0.59) skeletal, dental, soft tissue 23 m:13 f: 10 12.7 (1.28) FFA + brackets Jasper Jumper(n:15), Forsus (n:2) Mandibular anterior repositioning appliance (n:6) 2.44 (0.66) Eissa et al 2017 [26] RCT 14 m: 6 f: 9 12.52 (1.12) Forsus fatigue resistant + MBT brackets --- skeletal, dental, soft tissue Guimaraes et al 2013 [27] prospective 23 m:10 f:13 12.11 (1.36)

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23 2.3 Risk of bias within studies

Two retrospective and one prospective study had "yes" scores ranging between 50 to 69%, thus were considered as having a moderate risk of bias[24,25,27]. One RCT had more than 70% "yes" scores in the checklist thus had Low risk of bias[26]. Table 4 and Table 5 represent a summary of the bias evaluation.

Table 4. JBI Critical Appraisal Checklist for quasi-experimental studies Question Study Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 % of "yes" Risk of Bias Seben et al[24] ✓ ✓ 𝘟 𝘟 𝘟 𝘟 ✓ ✓ ✓ 55% Moderate Janson et al[25] ✓ ✓ 𝘟 𝘟 𝘟 _✓ _✓ _✓ _✓ 66% Moderate Guimaraes et al[27] ✓ 𝘟 𝘟 ✓ 𝘟 ✓ ✓ ✓ ✓ 66% Moderate ✓ : yes; 𝘟: No

Table 5. JBI Critical Appraisal Checklist for randomized Controlled trials Question Study Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 % of "yes" Risk of Bias Eissa et al [26] ✓ ✓ ✓ 𝘟 𝘟 ✓ NA ✓ ✓ ✓ ✓ ✓ ✓ 77% Low

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24 2.4 Skeletal Analysis

Results of skeletal cephalometric analysis of included studies are depicted in Table 6.

Both Seben et al [24] and Janson et al[25] reported that the premolars extraction group exhibited a mean decrease in SNA and ANB angles and an increase in mandibular length (CoGn) after the treatment. Seben et al [24]found that these changes were statistically significant; Moreover, he reported an insignificant decrease in SNB ( -0.24°, p=0.569 ) and an increase in SN-GoGn (0.35°, p=0.338); Conversely, Janson et al[25] reported an increase in SNB angle ( 0.36° (SD 1.39)) and decrease in SN-GoGn angle (- 0.62° (SD 2.52)).

Janson et al[25], Eissa et al [26]and Guimaraes et al[27] reported that functional appliances associated with fixed appliance treatment groups exhibited a mean decrease in SNA and ANB angles and an increase in SNB angle and Co-GN after the treatment. According to Eissa et al[26], only changes in SNA and ANB angles (-0.7° (SD 0.62), p<0.001) were significant; Furthermore, his reported increase in mandibular length (0.61mm (SD 2.74)) was insignificant and less than that reported by other studies. Contrasting findings were found regarding SN-GoGn angle. Janson et al[25] and Eissa et al[26] reported a slight increase in this angle, while Guimaraes et al[27] reported a decrease in SN-GoGn (-0.76° (SD 6.73))angle.

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25 Table 6. Skeletal analysis

Variable SNA (mean (SD)) ° SNB (mean (SD)) ° ANB (mean (SD)) ° Co-Gn (mean (SD)) mm SN-GoGn (mean (SD)) °

Study Interventio n T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 Seben et al[24] 2 PE 75.66 (4.73) 74.15 (3.96) -1.51 --- 70.79 (3.99) 70.55 (3.57) -0.24 --- 4.87 (2.58) 3.61 (2.20) -1.27 --- 107 (6.39) 111.55 (5.95) 4.05 --- 30.55 (5.59) 30.90 (5.61) 0.35 --- Janson et al[25] 2 PE 83.9 (3.69) 82.85 (3.53) -1.04 (2.12) 77.60 (3.05) 77.96 (3.34) 0.36 (1.39) 6.30 (2.59) 4.89 (2.13) -1.41 (1.66) 121.36 (6.23) 126.07 (7.20) 4.71 (3.73) 31.88 (5.62) 31.26 (5.99) - 0.62 (2.52) FAF 83.01 (3.46) 81.76 (4.01) -1.25 (2.93) 77.47 (2.62) 77.62 (2.83) 0.15 (2.31) 5.54 (2.68) 4.15 (3.03) -1.40 (1.59) 121.25 (6.60) 127.36 (7.11) 6.11 (4.26) 29.93 (3.76) 30.04 (4.60) 0.12 (2.94) Eissa et al[26] FAF 81.47 (4.04) 80.95 (3.97) -0.51 (0.57) 74.06 (3.16) 74.22 (3.17) 0.15 (0.48) 7.42 (2.8) 6.72 (3.12) -0.7 (0.62) 106.68 (6.58) 107.3 (5.29) 0.61 (2.74) 29.55 (5.88) 30.07 (5.99) 0.52 (1.51) Guimara es et al[27] FAF 81.80 (4.37) 81.54 (4.28) -0.26 (5.11) 75.70 (3.27) 77.20 (3.54) 1.50 (4.20) 6.09 (2.41) 4.35 (2.31) -1.74 (3.07) 104.81 (5.52) 108.89 (5.90) 4.08 (6.96) 30.47 (6.28) 29.72 (7.32) -0.76 (6.73) T1: Pretreatment; T2: Posttreatment; T2-T1: Treatment change

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26 2.5 Dental Analysis

Results of dental cephalometric analysis of studies are depicted in Table 7.

Both Seben et al [24]and Janson et al[25] reported premolars extraction treatment resulted in

decrease in 1-NA mm and 1-NA°, increase in 1-NB mm , 1-NB° and IMPA and reduction in overjet and overbite. According to Seben et al[24] , all reported dental changes were statistically significant except 1-NA°(-2.47°, p=0.080) which was not significant.

The reported effects of FAF treatment in Janson et al[25] , Guimaraes et al[27] and Eissa et al [26]studies were similar to the above mention effects of premolars extraction treatment.

According to Eissa et al[26], change in 1-NA mm (-1.98 mm (SD 2.06), p=0.014), 1-NA°( -6.88° (SD 4.15),p<0.001) and all other assessed dental cephalometric variables were statistically

significant. Guimaraes et al [27]reported a slight increase in 1-NA mm (0.15 mm ( SD 5.04)) which was less than that reported by other studies

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27 Table 7. Dental analysis

Variable 1-NA (mean (SD)) mm 1-NA (mean (SD)) ° 1-NB (mean (SD)) mm 1-NB (mean (SD)) ° IMPA (mean (SD)) ° Overjet (mean (SD))

mm Overbite (mean (SD)) mm Study Interve ntion T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 T1 T2 T2-T1 Seben et al [24] 2 PE 6.49 (3.17) 4.48 (2.67) -2.02 --- 25.23 (6.76) 22.76 (5.19) -2.47 --- 5.93 (1.79) 7.22 (1.57) 1.28 --- 24.60 (4.16) 28.13 (5.04) 3.52 --- 86.21 (5.36) 89.65 (6.38) 3.43 --- 7.63 (1.59) 2.32 (0.84) -5.31 --- 2.90 (2.92) 1.78 (1.12) -1.13 --- Janson et al [25] 2 PE 4.50 (3.36) 2.54 (2.23) -1.96 (3.16) 22.88 (7.19) 22.51 (6.59) -0.36 (7.82) 6.04 (2.36) 7.20 (2.01) 1.16 (1.35) 28.26 (5.44) 30.25 (4.11) 2 (5.13) 96.64 (6.07) 98.57 (6.19) 1.92 (5.56) 7.55 (1.69) 2.53 (0.54) -5.02 (1.69) 3.82 (2.03) 1.43 (0.77) -2.40 (1.77) FAF 5.27 (3.34) 4.07 (3.38) -1.20 (3.39) 24.94 (8.38) 21.66 (8.32) -3.29 (8.44) 5.69 (4.70) 8.02 (2.65) 2.18 (1.59) 27.13 (5.56) 33.19 (5.24) 6.07 (4.86) 97.07 (6.43) 102.7 (5.85) 5.69 (4.70) 7.56 (2.21) 2.55 (0.45) -5.01 (2.25) 4.78 (1.39) 1.91 (0.64) -2.87 (1.10) Eissa et al [26] FAF 4.69 (2.68) 2.71 (2.01) -1.98 (2.06) 20.93 (6.61) 14.05 (5.92) -6.88 (4.15) 7.529 (3) 9.02 (3.18) 1.5 (0.97) 32.11 (5.37) 38.11 (7.52) 6 (2.96) --- --- --- --- --- --- 6.54 (1.26) 2.06 (1.17) -4.47 (1.59) 4.21 (1.03) 2.41 (0.94) -1.8 (0.95) Guima raes et al[27] FAF 3.48 (3.60) 3.33 (2.87) -0.15 (5.04) 22.57 (8.32) 20.90 (4.60) -1.66 (9.75) 4.37 (2.31) 6.28 (2.80) 1.91 (3.17) 29.09 (5.52) 34.23 (7.19) 5.13 (8.65) 100.4 (6.94) 104.9 (7.76) 4.53 (8.49) 6.72 (2.31) 2.88 (1.58) -3.83 (3.02) 4.36 (1.82) 1.02 (1.64) -3.34 (1.97)

T1: Pretreatment; T2: Posttreatment; T2-T1: Treatment change

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28 2.6 Soft Tissue analysis

Only three of the included studies analyzed the effect of treatments on soft tissues. Results of soft tissue cephalometric analysis of studies are depicted in Table 8.

Both Seben et al[24] and Janson et al[25] reported that premolars extraction resulted in a decrease in UL-E line and LL-E line and an increase in NLA. According to Seben et al [24] both lips retrusion were statistically significant (UL-E line -2.28mm, p=0.00 ; LL-E line: -0.85mm,p= 0.004), but the change in NLA was not significant.

Similarly, Eissa et al[26] and Janson et al[25] reported that functional appliances associated with fixed appliance treatment resulted in a decrease in UL-E line and LL-E line and increase in NLA. However, according to Eissa et al[26] the lower lip retrusion was slight and insignificant (LL- E line: -0.02mm (SD 1.99), p=0.968 ) while changes in upper lip position ( UL-E line: -0.96 mm (SD 1.23), p=0.012 ) and nasolabial angle ( NLA: 5.68° (SD 8.12), p= 0.021) were significant .In this study, change in lips positions after treatment is less than that reported by other studies.

When Janson et al[25] compared premolars extraction treatment and functional appliances

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29 Table 8. Soft tissue analysis

T1: Pretreatment; T2: Posttreatment; T2-T1: Treatment change

SD: Standard deviation; 2 PE: Two premolars extraction; FAF: Functional appliance associated with fixed appliance

Variable UL-E (mean (SD)) mm LL-E (mean (SD))

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30

3- DISCUSSION OF RESULTS

This review compared Class II malocclusion treatment outcomes after two maxillary premolars extraction and functional appliance associated with fixed appliance by analyzing cephalometric results of clinical studies. Electronic search in several major databases yielded four studies

published in the last ten years that met the specific inclusion criteria. One study reported premolars extraction treatment effects [24], two studies reported on functional appliances associated with fixed appliance treatment effects [26,27], while only one study compared effects of both treatment methods[25]. This review included data from 119 patients (PE: 59 patients; FAF: 60 patients). 3.1 Skeletal analysis

No clinically significant difference has been recognized between both treatments' skeletal outcomes. Premolar's extraction and functional appliances associated with fixed appliance

treatments resulted in maxilla retrusion, reduction in ANB angle, and increase in mandibular length. These findings are consistent with other studies that considered the effects of premolars extraction or functional appliances in the treatment of Class II malocclusion [10,11,15,28].

Contrasting findings were found regarding skull base to mandibular plane angle SN-GoGn. Premolars extraction treatment in Janson et al's [25] study and FAF in Guimaraes et al's[27] study resulted in a decrease in SN-GoGn angle, while other included studies reported an increase in this angle. The reported decrease in SN-GoGn in both studies was small and insignificant. It can be attributed to the increase in the mandibular ramus height that occurred during growth [29]. Heterogenicity in SN-GoGn angle change is seen among other studies reporting functional

appliances or premolars extraction effects[30–33]. Porto et al[32], who studied the effects of PE on dolichofacial patients, concluded that premolars extraction does not affect the vertical growth pattern; it is the growth pattern type that controls the response of craniofacial structures to the treatment. When we compare the reported changes of SN-GoGn angle in PE and FAF treatments (PE: - 0.62° (SD 2.52) to 0.35°; FAF: -0.76° (SD 6.73) to 0.52° (SD 1.51)), we can infer that the difference is clinically insignificant

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31 1.39; FAF:0.15° (SD 0.48) to 1.50 °(SD 4.20)). One could expect that SNB angle would increase more in the functional appliances group since it is assumed that functional appliances induce condyle growth and its anterior repositioning in the glenoid fossa [34]. However, the studies showed that both treatment methods did not significantly increase SNB angle. Moreover, no clinically significant difference in change of mandibular length was noticed between both treatments (PE: 4.05mm to 4.71 (SD 3.73 ); FAF: 0.61mm (SD 2.74) to 6.11 (SD 4.26)). Our findings agree with other systematic reviews that concluded that functional appliance has only a slight effect on mandible sagittal position and attempts to fix the sagittal discrepancy through more dental alveolar than skeletal changes [10,11]. The slight increase in mandibular length at

posttreatment in Eissa et al's [26]study compared to other studies is due to the short observation period ( 6.06 months SD 0.76), which was not enough for mandible growth to occur.

3.2 Dental analysis

Dental cephalometric outcomes of both treatment methods showed: maxillary incisors retrusion and retroclination, mandibular incisors protrusion and proclination, increased incisor to mandibular plane angle, decreased overjet and overbite.

After a comparison of the reported cephalometric changes, no clinically significant difference in maxillary incisors retrusion (1-NA mm) between both treatment methods was found; However, maxillary incisors in the functional appliances treatment exhibited more retroclination in

comparison to the premolars extraction treatment as evident from the range of change of 1-NA° (PE: -0.36°(SD 7.82) to -2.47; FAF : -1.66°(SD 9.75) to -6.88°(SD 4.15)). This finding is in agreement with other reviews that concluded that functional appliances could significantly retrocline maxillary incisors [10,35] . However it is in contrast to Zelderloo et al[36] study that found that maxillary incisors tend to retrocline significantly after removable functional appliances treatment but procline again after the fixed appliance therapy resulting in overall insignificant proclination of maxillary incisors. The increased retroclination of maxillary incisors seen in the functional appliances group can be attributed to the distalizing effects of fixed functional appliances transmitted through the archwires to the incisors [26].

In comparison to maxillary premolars extraction treatment, functional appliances associated with fixed appliance showed more clinically significant proclination of mandibular incisors 1-NB° (PE: 2°(SD 5.14) to 3.52°; FAF : 5.13°(SD 8.65) to 6.07°(SD 4.86)) and increase in incisor to

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32 Only two studies provided data on change in molar relationship after treatment. Guimaraes et al[27] reported a decrease in molar relationship (-1.82mm ( SD 2.07)) after FAF treatment and a resultant Class I molar relationship. Seben et al[24] reported that PE resulted in a significant increase in molar relationship (1.56mm), indicating that Class II molar sagittal discrepancy became more accentuated after the treatment. This is an expected finding after two maxillary premolars extraction because molars are not subject to distalizing forces and can move further mesially into the

extraction space if they did not present with full cusp Class II at the beginning of the treatment[25].

3.3 Soft tissue analysis

Results of soft tissue cephalometric analysis show that maxillary premolars extraction and functional appliances associated with fixed appliance treatments resulted in upper and lower lip retrusion and increased nasolabial angle.

Upper lip retrusion was statistically significant in both treatments; however, there is a clinically insignificant difference between the outcomes of both treatments on upper lip position (PE: -2.28mm to -2.48mm (SD 1.42); FAF: -0.96 mm (SD 1.23) to -2.39mm (SD 1.90)).

Retrusion of lower lip in relation to E line was more pronounced in maxillary premolars extraction treatment (PE: -0.85mm to -1.08mm (SD 1.92); FAF: -0.02mm (SD 1.99) to -0.44mm (SD 1.92)). However, the difference between effects of both treatments on the lower lip was small and

clinically insignificant. Konstantonis et al [16] had a similar finding. We might speculate that the lower lip will not be affected or will protrude after either treatments due to the resultant protrusion and proclination of mandibular incisors. However, the fact that lower lips in some cases rest on the incisal third of maxillary incisors explains why maxillary incisors retraction induced lower lip retrusion [38]. Another factor that should be considered is the effect of nose and mandible growth on the E line's position. Since our population is growing patients, the nose and mandible growth would have caused the E line to be repositioned more anteriorly, thus increasing the distance between both lips and the esthetic line[39]. Significant mandibular growth did not occur in Eissa et al's [26] study due to the short observation period; this might explain why the amount of lip

retrusion presented in this study was less than in other studies.

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33 we can infer that changes were similar and there is no clinically significant difference between the effects of both treatments on the nasolabial angle. This finding is in contrast to Konstantonis et al[16]finding that the nasolabial angle was more significantly increased in the extraction group. The contrasting findings could be attributed to the difference in the patients' growth status between our reviews. For instance, this review included only studies with growing patients while Konstantonis et al[16] considered studies with different age groups. We must also note that their review included different malocclusion classes. Two other clinical studies comparing four premolars extraction and non-extraction treatments had contrasting findings. Verma et al [14] found a significant increase in NLA in favor of the extraction treatment, while Kirchnek et al[15] found no difference between both treatments.

In many cases, the response of soft tissues to the treatment might be unpredictable. For instance, the lips are affected by numerous factors such as initial lips thickness, teeth position and angulations, and mechanics and protocol of treatment [40] . Nasolabial angle is affected by lip thickness, nasal tip position and rotation during growth and sagittal position of the maxilla and maxillary

incisors[41]. All these factors make it difficult to predict the effect of the treatment on soft tissues. Tadic and Woods[40] suggested that patients with vertical growth pattern, thin lips at pretreatment, and initially increased nasolabial angle are expected to have unfavorable effects on the NLA after extraction treatment. Kostantonis et al[16]proposed that by controlling the amount of incisors retraction after premolars extraction treatment, we can minimize the amount of lips retraction and the unfavorable effects of treatment on facial esthetics. This can be done by closing the extraction space partially by mesialization of posterior teeth or using this space to compensate for crowding. 3.4 Other considerations

When evaluating a treatment, it is essential to investigate its beneficial and adverse effects. A reported adverse effect of functional appliances is their significant effect on mandibular incisors' position and inclination[35]. It can be speculated that this protrusive and proclined position of mandibular incisors could compromise those teeth' periodontal health and stability. Furthermore, we can expect that functional appliances treatment would adversely affect the temporomandibular joint health due to condylar repositioning. However, recent studies denied both speculations and reported that the proclined mandibular incisors do not adversely affect gingival health, nor does the functional appliance treatment harm the TMJ[42–44].

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34 angulation and eruption space. Thus, premolars extraction may provide more favorable conditions to the eruption of third molars and preventing their impaction[45,46].

Concerns about premolars extraction treatment effects on smile esthetic might arise. Cheng et al [47], which compared extraction and non-extraction treatment effects on smile esthetics, found no considerable differences between both treatments on smile esthetics and buccal corridors width. However, Fallas et al[48] inferred that maxillary premolars extraction increases vertical gingival display due to the extrusion of the incisors and their attached gingiva during anterior teeth retraction. The gingival display is directly proportional to the amount of incisors and canine

retraction. Regarding fascial esthetics, several authors who compared extraction and non-extraction treatment found that both treatments improve profile esthetics; however, premolars extraction treatment results in a more esthetic or attractive fascial profile than non-extraction treatment [16,49,50].

Our hypothesis was partially correct. There are no clinically significant differences between skeletal and soft tissue effects of both treatments. However, clinically significant differences exist between PE and FAF treatments' dental effects.

3.5 Limitations

This review's shortcomings would be the few number of studies included, their limited number of participants, and their moderate risk of bias. It would be ideal to include only randomized controlled trials directly comparing both treatment methods in this review to reduce the risk of bias, but this was not possible due to the shortage of RCTs in this subject. This can be explained by the fact that it is not ethical to randomly imply patients to extraction treatment or functional appliance treatment without obtaining consent and their participation in the decision process. Furthermore, the

participant and clinicians' blinding for the applied treatment method is not possible because the treatment method would be evident for both of them.

For PE and FAF treatments to be comparable, functional appliances needed to be associated with fixed brackets. Many studies were found regarding functional appliances treatment effects, but no associated fixed appliances were utilized, thus they were excluded. Furthermore, there were very few recent studies concerning this subject and a lack of studies comparing both treatment methods. For instance, only one included article directly compared both methods[25]; while for other

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35 Ali et al[51] found that 3D imaging, specifically Cone-beam computed tomography (CBCT), is the most efficient tool for assessing soft tissues and it is more reliable than conventional cephalometric. Therefore, It would have been ideal to include studies using CBCT imaging for accurate soft tissue analysis.

It is worth noting that the results observed after both treatment methods are not solely due to the assigned treatment but are partially attributed to the patients' growth occurring simultaneously during the treatment. Moreover, the headgear used for anchorage and the Class II elastics used for retention may have further affected the results. Although there was an attempt to match the included studies for pretreatment ANB, SN-GoGn, and overjet values, some differences were noted between other pretreatment cephalometric variables of studies. However, we cannot conclude that one treatment group had more severe malocclusion than the other.

In Eissa et al[26] study, posttreatment cephalometric radiographs were taken directly after removing the fixed functional appliance in contrast to other included studies in which posttreatment

cephalograms were taken after using Class II elastics and retention phase. This short observation period might not be enough for mandible growth to occur.

Since only one systematic review have been published recently comparing only soft tissue effects of extractions and non-extraction treatments in different malocclusion classes, this review was

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36

CONCLUSION

• There is no clinically significant difference between skeletal outcomes of maxillary premolars extraction and functional appliances associated with fixed appliance treatments.

• Functional appliances associated with fixed appliances treatment resulted in more clinically significant retroclination of maxillary incisors and proclination of mandibular incisors than premolars extraction treatment.

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37

PRACTICAL RECOMMENDATIONS

• Skeletal and soft tissue cephalometric changes should not be the main factors in deciding an extraction or non-extraction approach for Class II patients.

• Individualized treatment plan for each patient should be made according to patients' growth status, incisor position and inclination, amount of overjet, space discrepancy, premolars prognosis, initial lip thickness and position, position and angulation of maxillary third molars, and patient's and orthodontist's preferences.

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38

REFERENCES

1. Bilgic F, Gelgor IE, Celebi AA. Malocclusion prevalence and orthodontic treatment need in central Anatolian adolescents compared to European and other nations’ adolescents. Dent Press J Orthod. 2015;20(6):75–81.

2. Alhammadi MS, Halboub E, Fayed MS, Labib A, El-Saaidi C. Global distribution of malocclusion traits: A systematic review. Dent Press J Orthod. 2018;23(6).

3. Nishio C, Huynh N. Skeletal Malocclusion and Genetic Expression: An Evidence-Based Review. J Dent Sleep Med. 2016;03(02):57–63.

4. Nishi S, Basri R, Rahman N, Husein A, Alam M. Association between muscle activity and overjet in class II malocclusion with surface electromyography. J Orthod Sci. 2018;7(1):3. 5. Pace M, Cioffi I, D’antò V, Valletta A, Valletta R, Amato M. Facial attractiveness of skeletal

class I and class II malocclusion as perceived by laypeople, patients and clinicians. Minerva Stomatol. 2018;67(3):77–85.

6. Dutra SR, Pretti H, Martins MT, Bendo CB, Vale MP. Impact of malocclusion on the quality of life of children aged 8 to 10 years. Dent Press J Orthod. 2018;23(2):46–53.

7. Tehranchi A, Behnia H, Younessian F, Hadadpour S. Advances in Management of Class II Malocclusions. In: Motamedi MHK, editor. A Textbook of Advanced Oral and Maxillofacial Surgery Volume 3. InTech; 2016.

8. De Clerck H, Timmerman H. Distalization of the maxillary arch with miniplate anchorage. In: Skeletal Anchorage in Orthodontic Treatment of Class II Malocclusion. Elsevier; 2015. p. 118– 23.

9. DiBiase AT, Cobourne MT, Lee RT. The use of functional appliances in contemporary orthodontic practice. Br Dent J. 2015;218(3):123–8.

10. Koretsi V, Zymperdikas VF, Papageorgiou SN, Papadopoulos MA. Treatment effects of

removable functional appliances in patients with Class II malocclusion: a systematic review and meta-analysis. Eur J Orthod. 2015;37(4):418–34.

11. Zymperdikas VF, Koretsi V, Papageorgiou SN, Papadopoulos MA. Treatment effects of fixed functional appliances in patients with Class II malocclusion: a systematic review and meta-analysis. Eur J Orthod. 2016;38(2):113–26.

12. Evrard A, Tepedino M, Cattaneo P, Cornelis M. Which factors influence orthodontists in their decision to extract? A questionnaire survey. J Clin Exp Dent [Internet]. 2019;e432–8. Available from: http://www.medicinaoral.com/medoralfree01/aop/55709.pdf

13. Kocadereli İ. Changes in soft tissue profile after orthodontic treatment with and without extractions. Am J Orthod Dentofacial Orthop. 2002;122(1):67–72.

(39)

39 15. Kirschneck C, Proff P, Reicheneder C, Lippold C. Short-term effects of systematic premolar

extraction on lip profile, vertical dimension and cephalometric parameters in borderline patients for extraction therapy—a retrospective cohort study. Clin Oral Investig. 2016;20(4):865–74. 16. Konstantonis D, Vasileiou D, Papageorgiou SN, Eliades T. Soft tissue changes following

extraction vs. nonextraction orthodontic fixed appliance treatment: a systematic review and meta-analysis. Eur J Oral Sci. 2018;126(3):167–79.

17. Esenlik E, Bolat E, Findik Y. Relationship Between the Initial Position of Palatally Displaced Canines and Treatment Duration. Odovtos - Int J Dent Sci. 2020;287–300.

18. Hlongwa P. Cephalometric analysis: manual tracing of a lateral cephalogram. South Afr Dent J. 2019;74(6).

19. Warren JJ, Bishara SE, Ortho D. Duration of nutritive and nonnutritive sucking behaviors and their effects on the dental arches in the primary dentition. Am J Orthod Dentofacial Orthop. 2002;121(4):10.

20. Papamanou DA, Gkantidis N, Topouzelis N, Christou P. Appreciation of cleft lip and palate treatment outcome by professionals and laypeople. Eur J Orthod. 2012;34(5):553–60. 21. Moher D, Liberati A, Tetzlaff J, Altman DG, Group TP. Preferred Reporting Items for

Systematic Reviews and Meta-Analyses: The PRISMA Statement. PLoS Med. 2009;6(7). 22. Tufanaru C, Munn Z, Aromataris E, Campbell J, Hopp L. Chapter 3: Systematic reviews of

effectiveness. In: Aromataris E, Munn Z (Editors). JBI Manual for Evidence Synthesis. JBI, 2020. [Internet]. Available from: https://synthesismanual.jbi.global.

23. Goplen CM, Verbeek W, Kang SH, Jones CA, Voaklander DC, Churchill TA, et al.

Preoperative opioid use is associated with worse patient outcomes after Total joint arthroplasty: a systematic review and meta-analysis. BMC Musculoskelet Disord. 2019;20(1):234.

24. Seben MP, Valarelli FP, Freitas KMS de, Cançado RH, Bittencourt Neto AC. Cephalometric changes in Class II division 1 patients treated with two maxillary premolars extraction. Dent Press J Orthod. 2013;18(4):61–9.

25. Janson G, Castello Branco N, Aliaga-Del Castillo A, Henriques JFC, de Morais JF. Soft tissue treatment changes with fixed functional appliances and with maxillary premolar extraction in Class II division 1 malocclusion patients. Eur J Orthod. 2018;40(2):214–22.

26. Eissa O, El-Shennawy M, Gaballah S, El-Meehy G, El Bialy T. Treatment outcomes of Class II malocclusion cases treated with miniscrew-anchored Forsus Fatigue Resistant Device: A

randomized controlled trial. Angle Orthod. 2017;87(6):824–33.

27. Guimarães CH, Henriques JFC, Janson G, de Almeida MR, Araki J, Cançado RH, et al. Prospective study of dentoskeletal changes in Class II division malocclusion treatment with twin force bite corrector. Angle Orthod. 2013;83(2):319–26.

28. Pupulim DC, Henriques JFC, Janson G, Henriques FP, Freitas KMS, Garib D. Comparison of dentoskeletal and soft tissue effects of Class II malocclusion treatment with Jones Jig appliance and with maxillary first premolar extractions. Dent Press J Orthod. 2019;24(2):56–65.

(40)

40 30. Khoja A, Fida M, Shaikh A. Cephalometric evaluation of the effects of the Twin Block

appliance in subjects with Class II, Division 1 malocclusion amongst different cervical vertebral maturation stages. Dent Press J Orthod. 2016;21(3):73–84.

31. Taki AA. Effects of Functional Appliance Therapy on the Depth of the Pharyngeal Airways: Activator vs. Forsus. J Dent Health Oral Disord Ther. 2015;3(1).

32. Porto VS, Henriques JFC, Janson G, Freitas MR de, Pinzan A. Influence of treatment with and without extractions on the growth pattern of dolichofacial patients. Dent Press J Orthod. 2012;17(6):69–75.

33. Amirabadi Ge, Mirzaie M, Kushki Sm, Olyaee P. Cephalometric evaluation of soft tissue changes after extraction of upper first premolars in class ΙΙ div 1 patients. J Clin Exp Dent. 2014;e539–45.

34. Kyburz KS, Eliades T, Papageorgiou SN. What effect does functional appliance treatment have on the temporomandibular joint? A systematic review with meta-analysis. Prog Orthod.

2019;20(1):32.

35. Nielsen IL. Is Early Treatment With Functional Appliances Worth the Effort? A Discussion of the Pros and Cons of Early Interceptive Treatment. Iran J Orthod. 2016;In Press(In Press). 36. Zelderloo A, Cadenas de Llano-Pérula M, Verdonck A, Fieuws S, Willems G. Cephalometric

appraisal of Class II treatment effects after functional and fixed appliances: a retrospective study. Eur J Orthod. 2016;cjw064.

37. Daokar S, Sharma M. A Systematic Review of Skeletal, Dental and Soft Tissue Treatment Effects of Twin Block Appliance. Orthod J Nepal. 2020;10(1):65–72.

38. Assistant Professor, Department of Orthodontics, Al-Ameen Dental College, Vijaypur, Karnataka 586108 India, S Nidavani S, Halkati M, Professor and Head, Department of

Orthodontics, Al-Ameen Dental College, Vijaypur, Karnataka 586108 India, Ahmed Galagali S, Reader, Department of Orthodontics, Al-Ameen Dental College, Vijaypur, Karnataka 586108 India. Effect of Incisor Retraction on the Lips in Patients with Excessive Proclination. Indian J Dent Educ. 2019;12(2):41–4.

39. Frye L, Diedrich PR, Kinzinger GSM. Class II Treatment with Fixed Functional Orthodontic Appliances before and after the Pubertal Growth Peak – A Cephalometric Study to Evaluate Differential Therapeutic Effects. J Orofac Orthop Fortschritte Kieferorthopädie.

2009;70(6):511–27.

40. Tadic N, Woods MG. Incisal and Soft Tissue Effects of Maxillary Premolar Extraction in Class II Treatment. Angle Orthod. 2007;77(5):808–16.

41. Bunnell A, Fattahi T. Nasolabial Angle Modifications Following Maxillary Surgery. J Oral Maxillofac Surg. 2014;72(9):e22–3.

42. Renkema A-M, Navratilova Z, Mazurova K, Katsaros C, Fudalej PS. Gingival labial recessions and the post-treatment proclination of mandibular incisors. Eur J Orthod. 2015;37(5):508–13. 43. Tepedino M, Franchi L, Fabbro O, Chimenti C. Post-orthodontic lower incisor inclination and

(41)

41 44. Ivorra-Carbonell L, Montiel-Company J, Almerich-Silla J, Paredes-Gallardo V, Bellot-Arcis C.

Impact of functional mandibular advancement appliances on the temporomandibular joint - a systematic review. Med Oral Patol Oral Cirugia Bucal. 2016;0–0.

45. Gohilot A, Pradhan T, Keluskar KM. Effects of first premolar extraction on maxillary and mandibular third molar angulation after orthodontic therapy. J Oral Biol Craniofacial Res. 2012;2(2):97–104.

46. Pan F, Yang Z, Wang J, Cai R, Liu J, Zhang C, et al. Influence of orthodontic treatment with premolar extraction on the spatial position of maxillary third molars in adult patients: a retrospective cohort cone-bean computed tomography study. BMC Oral Health.

2020;20(1):321.

47. Cheng H-C, Wang Y-C, Tam K-W, Yen M-F. Effects of tooth extraction on smile esthetics and the buccal corridor: A meta-analysis. J Dent Sci. 2016;11(4):387–93.

48. Fallas Mf, Abu-Alhaija Es, Alkhateeb Sn, Samawi Ss. Vertical gingival display changes associated with upper premolars extraction orthodontic treatment: A prospective clinical trial. J Clin Exp Dent. 2020;e1050–7.

49. Mendes LM, Janson G, Zingaretti Junqueira-Mendes CH, Garib DG. Long-term profile

attractiveness in Class II Division 1 malocclusion patients treated with and without extractions. Am J Orthod Dentofacial Orthop. 2019;155(3):362–71.

50. Lim H-J, Ko K-T, Hwang H-S. Esthetic impact of premolar extraction and nonextraction treatments on Korean borderline patients. Am J Orthod Dentofacial Orthop. 2008;133(4):524– 31.

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42

ANNEXES

Annex 1

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44 Annex 2

Functional appliances

Fig.1. Forsus Fatigue Resistant device (FRD)

https://www.vistanciaortho.com/forsus-fatigue-resistance-device/

Fig.2. Jasper jumper (JJ)

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45 Fig.3. Twin force bite corrector (TFBC)

https://shop.fivestarortho.com/products/twin-force-bite-corrector-device-dual-lock

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46 Premolars extraction

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48

The Comparison of Class II Malocclusion Treatment Outcomes between Maxillary Premolars Extraction and Functional Appliance Associated with Fixed Appliance

Rand Bahro