Effect of Bilateral Distalization of Upper First Molars in a Group of Patients After Extraction of Maxillary Second Molars Using Infra Zygomatic Mini Implants: A Prospective Clinical Trial
Phase: NA
Conditions: Class II Malocclusion
Sponsor: Future University in Egypt

 
1 
 
Effect of Bilateral Distalization of Upper First 
Molars in a Group of Patients after extraction 
of Maxillary Second Molars Using Infra 
Zygomatic Mini Implants 
Prospective clinical trial 
  
 
 
 
 
 
 
in
 
degree
 
master’s
 
of
 
fulfillment
 
partial
 
the
 
for
 
submitted
 
Protocol
s
Orthodontic
 
Faculty of Dentistry, Future University in Egypt 
 
 
 
 
 
Submitted by 
Name: Hosam Abdullah Mohamed Zaza 
B.D.S. Future University, 2017 
 (2020) 
 
 

 
2 
 
I. Administrative Information 
 
1.  Title:  
 
Effect of bilateral distalization of upper first molars in a group of patients 
after extraction of upper second molar using infra zygomatic mini 
implants 
 
2. Trial registration:  
Trial will be registered in www.clinicaltrials.gov  
  
3. Protocol version: 
July -2020, First version.  
 
4. Funding:  
This research is self-funded. 
 
5.  Roles and responsibilities: 
Main supervisor: -  
• Prof. Nagwa Al Mangoury (NM), BDS, MSC, PHD, FDS(RCSEd). 
Professor of orthodontics at the faculty of oral & dental medicine, Future 
university: Helped in developing the idea of the research, will help in 
interpretation of results and drawing conclusions. 
Co-supervisor: - 
• Dr. Amr El-Dakroury (AD), BDS, MSC, PhD, Associate professor – 
Department of Orthodontics and Dentofacial Orthopedics, Cairo University, 
(Co-supervisor): Calculated the sample size, also will help in following up of 
patients, creating analysis and interpretation of the results. 
 
Co-supervisor: - 
• Dr. Mostafa Mohamed El-Dawlatly (ED), BDS, MSC, MOrth, PhD 
(RCSEd), Lecturer of orthodontics at the faculty of dentistry, Cairo University, 
(Co-supervisor): Initiated the idea of the project and helped in designing the 
mechanics of the new appliance. Also, will be responsible for clinical part of the 
study, interpreting the outcomes and aide in the writing phase. 
 

 
3 
 
Principle investigator: - 
• Hosam Abdullah Mohamed Zaza (HZ), BDS, (Principal Investigator): Will 
be responsible for the clinical part of the study, sample recruitment, follow up 
of patients, writing the thesis, interpretation of results.  
 
 
Committees: 
 Department of Orthodontics and Dentofacial Orthopedics Council 
 College Board Committee 
 Ethics Committee 

 
4 
 
II. INTRODUCTION 
 
 
 
Class II malocclusion is considered to be a prevalent type of 
malocclusion, which can be observed in almost 1/3 of the population1. Class II 
malocclusion can be either dental and/or skeletal, each having their own 
characteristics. These characteristics are usually expressed simultaneously, but 
to different extents. The dental component is expressed when the buccal groove 
of the mandibular first molar is distally positioned to the mesio-buccal cusp of 
the maxillary first molar. As for the skeletal component, it is expressed through 
the antero-posterior disproportions of the jaws relative to each other2. 
Individuals with Class II Malocclusion usually suffer from functional defects & 
impaired masticatory function3,4, which is directly related to this type of 
malocclusion5. 
 
 
The skeletal disproportion is usually due to either mandibular retrusion, 
maxillary protrusion, or both. The total and lower face heights could be either 
decreased, normal or increased. However, an increased vertical height is more 
likely associated with skeletal class II cases2. The anteroposterior relationships 
of teeth with Class II malocclusion doesn’t improve spontaneously with age2. 
Therefore, correction of this type of skeletal problem in preadolescents is 
advocated. 
 
 
Treatment of Class II malocclusion could be divided into four 
different 
treatment methods: Growth modification with the use of either extraoral 
headgears or functional orthopaedic appliances; distalization of maxillary 
molars; Retraction of maxillary anterior teeth into extraction spaces of 
premolars (camouflage treatment); Combination of distalization of maxillary 
teeth and protraction of mandibular teeth. The latter 3 methods of treatment 
involve dental movement only, while the first method encompasses both dental 
and skeletal alterations1. 
 
 
 
 
 

 
5 
 
 Conventionally, to treat class II in adult patients with an increased 
overjet, we would extract the upper first premolars and retract the anterior 
segment into the extraction space. However, the therapeutic option of extracting 
the upper second molar would enable faster first molar retraction6. Furthermore, 
the impact of extracting the upper second molar on patient profile is minimal 
compared with conventional treatments performed with first premolar 
extraction. Also, when the second molar is extracted the possibility of third 
molar impaction is decreased, the third molar usually comes into occlusion and 
in most cases spontaneously assumes a favorable position relative to the first 
molar6. 
 
Furthermore, in some class II cases extraction is not an option because of 
the patient’s profile such as naso-labial angle & lip thickness as extraction will 
result in an improper soft-tissue profile because of maxillary incisors up 
righting7. In such cases distalization of maxillary arch using mini-implants has 
been introduced in order to achieve a proper class I relation without 
jeopardizing the harmony of the soft tissue profile8.  
 
In adults with erupted maxillary third molars & badly decayed or 
unilaterally extracted second molars, extraction of these upper second molars is 
recommended to provide sufficient space for arch distalization instead of 
maxillary third molars9. The extraction site will provide sufficient space for 
distillization. The extraction socket, if recent, will also result in regional 
acceleratory phenomena, which can help with accelerating molar distalization10, 
Furthermore, distalization of maxillary molars after extracting the second molar 
will have the added benefit of achieving a Class I molar relationship10. 
Distalization of the first molar can be done by using means of extraoral or 
intraoral forces. Several methods and devices can be used. The most 
conventional method for distalization involves the use of cervical headgear, 
which can be either used for orthodontic or orthopaedic corrections. It is easy to 
apply and may distalize not only the maxillary first molars but also the first 
second premolars via trans-septal fibers11. 
  
However, the short comings of using cervical headgear was apparent in 
the undesirable lateral forces that tend to move maxillary molars into crossbite, 
which is unavoidable12. In addition to this, the success of the treatment depends 
heavily on patient cooperation, and lack of patient cooperation results in loss of 
anchorage and unsatisfactory treatment results. 

 
6 
 
The disadvantages of the extraoral appliances have motivated many 
researchers to develop several mechanics of intraoral molar distalization. 
Numerous intraoral appliances have been used to distalize the maxillary molars 
in Class II patients without relying on patient’s cooperation; these include 
nickel-titanium spring13–15, magnet13, distal jet16,17, first class18, Jones jig19,20, 
pendulum19,21, and Keles slider12,22 appliances. All of these intraoral 
distalization appliances were used to distalize the maxillary molars; however, in 
most of these appliances mentioned above, anchorage loss was unavoidable, 
characterized by the protrusion of maxillary incisors, increase in overjet, and 
decrease in overbite23,24. Recent studies have suggested the use of mini 
implants25,26, and plates27,28 as anchorage units in orthodontic patients requiring 
distalization, which also eliminated the dependence on patient co-operation. 
 
With our proposed distalizer using infra-zygomatic mini screws, the 
orthodontic fixed appliance is postponed till after the stage of distalization. 
Delaying the bonding procedure will decrease the risk of adverse effects of 
fixed orthodontic appliances, such as enamel decalcifications as well as labial 
flaring of the anterior teeth. 
 
There is a scarcity in the current literature regarding such appliance and 
its effect on distalizing the first maxillary molar in absence of the second molar. 
Therefore, this study was made to evaluate the effect of bilateral distalization of 
upper first molars in a group of patients after extraction of maxillary second 
Molars using infra zygomatic mini implants. 
 
Statement of the problem: 
The appliances available for distalization used to be mainly extraoral 
distalizing appliances which depended entirely on patient cooperation and 
compliance29. Even after the emergence of intra-oral distalizing appliances they had 
adverse dentoalveolar effect such as anchorage loss and flaring of the upper anterior 
teeth30. Thus, this study was made in order to evaluate the efficiency of our 
proposed appliance in the treatment of Class II patients while avoiding the adverse 
effects mentioned above. 

 
7 
 
Rationale for carrying out the trial: 
To evaluate the efficiency of the proposed appliance in distalizing maxillary 
1st molars in adults after extraction of upper second molars to achieve class I molar 
relation. Furthermore, to evaluate all the dentoalveolar changes that will occur while 
using the proposed appliance. 
 
Literature Review: 
A) Class II: 
Angle (1907), Classified malocclusion by dividing it into class I, class II and class 
III malocclusion according to maxillary first permanent molar & its relation to the 
mandibular first permanentmolar31. 
 
Moyers et al (1980), Studied the differential diagnosis of class II malocclusions by 
means of computer-based statistical methods, several types of Class II malocclusion 
have been discovered with defining horizontal and vertical characteristics. Of the six 
horizontal types, four are severe syndromes, one is a loose, ill-defined grouping of 
cases with mild skeletal features, and one has only the dental features of Class II. 
Five vertical types associate with Class II were also revealed, although each vertical 
is not associated with all horizontal types. A simplified simulation of the 
computerized procedures has been developed for routine use in clinical practice32.  
 
 

 
8 
 
B) Maxillary molar distalization: 
Joydeep Ghosh et al (1996), determined the effects of the pendulum appliance on 
distalization of maxillary molars and the reciprocal effects on the anchor premolars 
and maxillary incisors. Initial and follow-up cephalometric radiographs were 
obtained on 41 subjects (26 girls and 15 boys) who were treated with the pendulum 
appliance for bilateral distalization of the maxillary first molar teeth. Dental casts 
were available on 31 patients. Dental, skeletal, and soft tissue changes were 
determined. The mean maxillary first molar distalization was 3.37 mm, with a distal 
tipping of 8.36. The maxillary second molars were also distalized 2.27 mm. it was 
concluded that the pendulum appliance is an effective and reliable method for 
distalizing maxillary molars, provided the anchor unit is adequately reinforced. Its 
major advantages are minimal dependence on patient compliance, ease of 
fabrication, one-time activation, adjustment of the springs if necessary, to correct 
minor transverse and vertical molar positions, and patient-acceptance33. 
Pavlick C. T. (1998), Concluded that Superb clinical results, supported by research 
indicate that cervical headgears, when used correctly according to the principles of 
the Bioprogressive philosophy, will produce the most desirable and predictable 
orthopedic desirable orthopaedic changes in growing faces34.  
Sugawara et al. (2006), reported that the zygomatic process of the maxilla 
could be used to prevent the anchorage loss. He used mini plates placed in the 
zygomatic buttress for molar distalization in non-growing patients28.  
 
Nur et al. (2012), designed an intraoral appliance, named the Zygoma-Gear 
Appliance (ZGA), for bilateral maxillary molar distalization using the titanium 
anchor plates placed in the zygomatic process of the maxilla. The authors 
demonstrated that an effective maxillary molar distalization without anchorage 
loss could be achieved in a short time using the ZGA35. 
 

 
9 
 
El Dawlatly et al. (2014), Suggested the use of Orthodontic mini implants 
placed in the zygomatic buttress to act as anchorage for the distalization. The 
authors recommend this treatment technique for growing class II patients with 
increased upper incisors and gingival display36. 
 
C) Reliability of scanned models: 
Nalcaci et al (2014), The aim of this study was to evaluate the reliability of 
measurements obtained after the superimposition of three-dimensional (3D) digital 
models by comparing them with those obtained from lateral cephalometric 
radiographs and photocopies of plaster models for the evaluation of upper molar 
distalization. No significant difference was observed regarding the amount of molar 
distalization among the three groups, therefor 3D digital models are reliable to 
assess the results of upper molar distalization and can be considered a valid 
alternative to conventional measurement methods37. 
L. S. Lemos et al. (2015), The aim of this study was to evaluate the reliability of 
measurements made on digital cast models scanned in the 3Shape R700 scanner 
(3Shape, Copenhagen, Denmark) that uses a non-destructive laser beam to 
reproduce model surfaces so that the plaster model is not destroyed. The sample 
consisted of 26 cast models. Six linear measurements were made on the cast models 
and then compared on the digitalized cast models. The study concluded that The 
digital models obtained from the 3 Shape R 700 scanner are reliable and can be 
considered an alternative to cast models for performing measurements and analyses 
in orthodontic practice38. 
 
 
  

 
10 
 
D) Reliability of CBCT: 
Periago et al. (2008), He compared the accuracy of linear measurements made on 
cone beam computed tomographic (CBCT) derived 3-dimensional (3D) surface 
rendered volumetric images to direct measurements made on human skulls and 
concluded that While many linear measurements between cephalometric landmarks 
on 3D volumetric surface renderings obtained using Dolphin 3D software generated 
from CBCT datasets may be statistically signiﬁcantly different from anatomic 
dimensions, most can be considered to be sufﬁciently clinically accurate for 
craniofacial analyses39. 
E) Mini-implants: 
Shingo Kuroda et al. (2007), Evaluated the clinical usefulness of mini-
implants as orthodontic anchorage. examined their success rates, analyzed 
factors associated with their stability, and evaluated patients' postoperative 
pain and discomfort with a retrospective questionnaire. Seventy-five patients, 
116 titanium screws of 2 types, and 38 miniplates were retrospectively 
examined. The success rate for each type of implant was greater than 80%. 
He concluded that miniscrews placed without flap surgery have high success 
rates with less pain and discomfort after surgery than miniscrews placed with 
flap surgery or miniplates placed with either procedure40. 
Database research: 
A search was performed on electronic databases (PubMed, Cochrane library). 
 
 

 
11 
 
III- Aim of the study 
 The aim of this study is to evaluate the  Effect of Bilateral Distalization of 
Upper First Molars in a Group of Patients after extraction of Maxillary Second 
Molars Using Infra Zygomatic Mini Implants. 
 
A-PICO format : 
 
Patient/Population : 
Adult patients having Class II molar relation. And indicated for maxillary molar 
distalization. 
 
Intervention: 
Infra-zygomatic mini implant supported maxillary intra oral appliance & 
extraction of maxillary second molars. 
 
Comparator: 
Pre-treatment and post treatment maxillary and mandibular changes.  
 
 
 
 
 

 
12 
 
Out-come mesure(s): 
Prioritization 
of the outcome 
outcome 
Method of 
measurement 
Unit of 
measurement 
primary 
Anteroposterior 
Dental changes in 
the upper buccal 
segment 
Scanned dental 
cast e.g. (MB cusp 
of U6-MB groove 
of L6) 
CBCT 
Millimeters 
 
 
secondary 
other dental 
changes in upper 
buccal segment 
including 
(intermolar width, 
molar inclination,) 
Scanned dental 
cast 
CBCT 
Millimeters and 
degrees 
 
dental changes in 
mandibular teeth. 
Scanned dental 
cast 
Millimeters 
 
 
B-Research question : 
Will the proposed appliance be able to induce dental effects for correction of 
class II malocclusion in adult patients after extraction of upper second molars 
within the duration of eight months? 
 
 

 
13 
 
IV-Objectives of the study 
•Research hypothesis: 
The null hypothesis of this research is that there are no dental changes 
associated with the use of proposed appliance. 
•Primary objective (s): 
Amount and rate of maxillary 1st molar Distalization.  
•Secondary objective: 
Evaluate the other dental changes in the upper buccal segment accompanying 
the Distalization technique and the consequent dental changes in the mandibular 
arch.  
•Study design 
Prospective clinical trial. 
V- Methods (-participants, interventions and outcomes) 
•Study settings: 
The study will be performed in the outpatient clinic of the Orthodontics and 
Dentofacial Orthopedics Department at the Faculty of Oral and Dental 
Medicine, Future University in Egypt. The recruited sample would be from the 
Egyptian population. 
 
 

 
14 
 
Eligibility criteria: 
Inclusion criteria: 
1-Patients with CVMI index 5 & 6. 
2-From quarter unit to 3\4-unit class II molar relationship. 
3-An overjet of an average 6mm. 
4-Full set of permanent dentition except for the maxillary second molar. 
5-Favorable path of eruption for the maxillary third molar. 
Exclusion criteria: 
1- Medically compromised Patients. 
2-Patients under long term medications. 
3- Patients having sever periodontal disease. 
4-Any other age group. 
5-Full unit class II cases. 
•Intervention: 
A) Medical History Questionnaire will be filled by the patient to exclude the 
presence of any systemic condition.  
B) Clinical Examination: 
Proper examination of the oral structures including teeth which will be 
examined for caries, fracture or missing teeth and Gingival tissues which will be 
examined for gingivitis, periodontitis, attachment loss, gingival recession, oral 
lesions and the nature of the gingival biotype. 

 
15 
 
 
 C-Diagnosis: 
The patient is checked to fulfil the previously mentioned inclusion criteria.  
Full set of records will be taken for every patient as part of the routine 
procedure for treatment of patients in the outpatient clinic of the Department of 
Orthodontics and Dentofacial Orthopedics, Future University in Egypt. 
 D-Clinical Procedures: 
Proper disinfection will be performed with a local disinfectant, BETADINE 
povidone-iodine 10%, at the area of mini implant insertion. 
Two infra zygomatic mini-implants will be placed (Screw Tomas pin 10mm, 
dentaurum, Germany). 
Bands will be cemented to upper first molars. 
The inner bow (1.2mm) is a modified version of the inner part of a conventional 
face bow. Two hooks were soldered onto the inner bow distal to the lateral 
incisor teeth regions, and U loop at 1st premolar region, and bends acting as 
mesial stop will be bent in front of the maxillary first molars. 
The inner bow will be adjusted to the headgear tubes on the maxillary first 
molar bands, as the anterior component of the inner bow is 3 mm free from the 
labial surface of anterior teeth. 
Orthodontic force 350 mg per side Will be delivered by Niti closed coil spring 
which is attached from infra zygomatic mini screw to the hook soldered to the 
wire framework. 

 
16 
 
Patient will wear mandibular thermoform retainer at night only. 
E-Follow up period: 
The patient will be asked to attend follow up visits every 4 weeks to check the 
following: 
A) The stability of the mini implants 
B) The activity of the appliance (force recalibration is required). 
C) The amount of correction achieved. 
D) Any inflammation related to the appliance or the mini implants  
Impressions and wax bite will be taken (without the appliance in place) 
followed by digital scanning of produced models). 
F-Criteria for discontinuing intervention: 
Any harmful effects to the patient from any of the treatment modalities  
Lack of patient co-operation   
Outcomes: 
Primary: Anteroposterior position changes of upper first molars.  
Secondary: Other dental changes in upper post segment and mandibular dental 
arch.  
Methods of measuring of all outcomes:  
Linear and angular measurements Will be made on the pre, post and follow-up 
dental scanned casts and on the CBCT to assess the dental changes in 
intervention group.  

 
17 
 
 
Units of measurement:  
Millimetres and degrees 
 
Blinding:  
•Due to the nature of the study, the operator and patients can't be blinded. 
Blinding of the outcome assessors can be done by sealing the name of the 
patient in the pre and post treatment radiographs used for analysis.  
 
VI- Sample size 
  
Our sample size calculation is based on a previous study31 evaluating the 
dentoalveolar, skeletal, and soft tissue effects of the Zygoma-Gear Appliance 
(ZGA) when used for bilateral distalization of the maxillary molars.  as the 
Primary outcome values was: 
                   Before                       After                  Difference 
VRL-U6       32.05 ± 4.01            27.66±4.17         -4.36± 2.15 
The plan of the study is a continuous response variable from matched pairs of 
study subjects.  Prior data indicate that the difference in the response of matched 
pairs is normally distributed with standard deviation 2.15.  If the true difference 
in the mean response of matched pairs is 4.36, we will need to study 5 pairs of 
subjects to be able to reject the null hypothesis that this response difference is 
zero with probability (power) 0.8.   The Type I error probability associated with 
this test of this null hypothesis is 0.05. So, to count for drop out or missing data 
a sample of size of 8 pairs of subjects is recommended 

 
18 
 
Type of test: Paired t Test 
Minitab software output. 
Sample       Target 
Difference     Size            Power        Actual Power 
4.36          5                0.8              0.915696 
5.0
2.5
0.0
-2.5
-5.0
1.0
0.8
0.6
0.4
0.2
0.0
Difference
Power
A lpha
0.05
StDev
2.15
A lternativ e
Not =
A ssumptions
5
Size
Sample
Power Curve for Paired t Test
 
To count for drop out or missing data a sample of size 8 is recommended 
VII-Data collection, management and analysis: 
Patients recruited from the clinic at the department of orthodontics at Future 
university in Egypt 
The data collection for the primary and secondary outcomes will be done by 
taking scanned dental casts and CBCT. 
Pre and post treatment/ observation period in the treatment 

 
19 
 
Plans to promote participants retention and complete follow-up: 
 Telephone numbers of all patients included in the study will be recorded 
as a part of the written consent. 
 All patients will be given reminder phone calls at the time of the 
predetermined follow updates. 
 Patient punctuality at appointments, number of missed appointments will 
be regularly monitored. 
 
 Data management: 
 All data will be electronically entered in the computer at the Department 
of Orthodontics and Dentofacial Orthopedics. The data should include all 
photographs, models and radiographs. 
 Resulted data from scanned cast analysis will be organized in excel sheets 
that will be electronically entered and backed up in a google drive for 
permanent storage. 
 The patients' data should have sequential numbers that will be revised at 
each step to avoid any mixing of data between patients. 
 
Statistical analysis: 
The principle investigator will be responsible for the extraction of the 
required data from the CBCT taken before and after retraction as well as the 
study models taken at every follow up visit. The data will be sent to a 
specialized statistician. 
 
 
 

 
20 
 
VIII-Monitoring: 
A) Data monitoring: 
 Monitoring of the study will be strictly done by the supervisors periodically. 
They will monitor all the steps of the followed protocol and find solutions to all 
troubles that have occurred during the trial performance. 
B) Harms: 
 If any harm occurs to the patient before entry to the study, it will be reported as 
unrelated. If it happens after, it will be recorded and documented by the primary 
investigator. Severity of harms and potential causal relationship with 
intervention will be addressed. In cases of inflammation of the tissue around the 
mini-implant, immediate removal of the mini-implant and prescription of anti-
inflammatory drugs will be done in order to subside the inflammation followed 
by replacement of the mini-implant after the resolution of the inflammation.     
C) Auditing: 
The supervisor will follow up and review the different interventions and 
resulting data. And he will periodically follow up the trial progress including 
recruitment of patients, adherence to interventions and reporting of harms. A 
meeting with the senior supervisor will be set to monitor the progress of the 
study and the need for any adjustments. 
 
Research ethics approval:  
This protocol and the template informed consent form will be reviewed by the 
Ethics Committee of Scientific Research –Faculty of Oral and Dental Medicine- 
Future University in Egypt.) 
 

 
21 
 
Protocol amendments: 
Any modification to the protocol which may have an impact on the conduct of 
the study, potential benefit of the patient or may affect patient safety will 
require a formal amendment to the protocol. Such amendment will be agreed 
upon by the Department of Orthodontics and Dentofacial Orthopedics, Faculty 
of Oral and Dental Medicine, Future University in Egypt and the Ethics 
Committee will approve such amendment before proceeding in the study.  
 
Consent: 
The main investigator will be in charge for detailed explanation and elaboration 
of the different steps of the study interventions for each patient. Then will ask 
every participant to sign a written consent before they begin treatment. The 
consent will be written in Arabic.  
 
 
Confidentiality: 
The main investigator will store any personal information about the participants 
collected during the study separately from study records in locked files in areas 
with only access to the supervisors responsible for auditing and analysis. Also, 
will keep the files in the Department of Orthodontics and Dentofacial 
Orthopedics, Faculty of Oral and Dental Medicine, Future University in Egypt 
and will identify all the reports, data and administrative forms by a coded ID 
number to maintain participant confidentiality. Participant information won't be 
used outside the study except with written permission of the participant.  
 
 

 
22 
 
Declaration of interests: 
No financial interests are to be declared by the supervisors and the principle 
operator. This study is a part of a Masters’ degree in Orthodontics, Faculty of 
Oral and Dental Medicine, Future University in Egypt and it is self-funded by 
the principal investigator.  
Ancillary and Post Trial Care: 
Any complication associated with the intervention will be managed by the 
principal operator. Then the patients will continue their regular orthodontic 
treatment according to the treatment plan described 
Dissemination policy: 
The trial results will be available to the participants, health care professionals 
and the public by publication of the study in high quality national and 
international journals. The principal investigator will present a copy of the 
thesis at the Faculty of Oral and Dental Medicine, Future University in Egypt 
library and will distribute additional copies among the main universities in 
Egypt. 
 
 
 
 
 
 

 
23 
 
IX- References 
1.  
Proffit WR, Fields HW, Sarver DM. Contemporary Orthodontics. St. Louis, Mo.: 
Elsevier/Mosby; 2013. 
2.  
Bishara SE. Class II malocclusions: Diagnostic and clinical considerations with and 
without treatment. Semin Orthod. 2006. 
3.  
English JD, Buschang PH, Throckmorton GS. Does Malocclusion Affect Masticatory 
Performance? Angle Orthod. 2002. 
4.  
Toro A, Buschang PH, Throckmorton G, Roldán S. Masticatory performance in 
children and adolescents with class I and II malocclusions. Eur J Orthod. 2006. 
5.  
Owens S, Buschang PH, Throckmorton GS, Palmer L, English J. Masticatory 
performance and areas of occlusal contact and near contact in subjects with normal 
occlusion and malocclusion. Am J Orthod Dentofac Orthop. 2002. 
6.  
Mezomo MB, Pierret M, Rosenbach G, Tavares ACE. Extraction of upper second 
molars for treatment of Angle Class II malocclusion. Dental Press J Orthod. 2010. 
7.  
Vaden JL, Williams RA, Goforth RL. Class II correction: Extraction or nonextraction? 
Am J Orthod Dentofac Orthop. 2018. 
8.  
Lee SK, Abbas NH, Bayome M, et al. A comparison of treatment effects of total arch 
distalization using modified C-palatal plate vs buccal miniscrews. Angle Orthod. 2018. 
9.  
Basdra EK, Stellzig A, Komposch G. Extraction of maxillary second molars in the 
treatment of Class II malocclusion. Angle Orthod. 1996. 
10.  
Liversidge HM. Timing of human mandibular third molar formation. Ann Hum Biol. 
2008. 
11.  
Nalçaci R, Biçakçi AA, Ozan F. Noncompliance screw supported maxillary molar 
distalization in a parallel manner. Korean J Orthod. 2010. 
12.  
Keles A. Maxillary unilateral molar distalization with sliding mechanics: A 
preliminary investigation. Eur J Orthod. 2001. 
13.  
Bondemark L, Kurol J, Bernhold M. Repelling magnets versus superelastic nickel-
titanium coils in simultaneous distal movement of maxillary first and second molars. 
Angle Orthod. 1994. 
14.  
Keim RG, Berkman C. Intra-arch maxillary molar distalization appliances for Class II 
correction. J Clin Orthod. 2004. 
15.  
Karlsson I, Bondemark L. Intraoral Maxillary Molar Distalization. Angle Orthod. 
2006. 
16.  
Ngantung V, Nanda RS, Bowman SJ. Posttreatment evaluation of the distal jet 
appliance. Am J Orthod Dentofac Orthop. 2001. 
17.  
Bolla E, Muratore F, Carano A, Bowman SJ. Evaluation of Maxillary Molar 
Distalization with the Distal Jet: A Comparison with Other Contemporary Methods. 
Angle Orthod. 2002. 
 

 
24 
 
18.  
Fortini A, Lupoli M, Parri M. The First Class Appliance for rapid molar distalization. J 
Clin Orthod. 1999. 
19.  
Patel MP, Janson G, Henriques JFC, et al. Comparative distalization effects of Jones 
jig and pendulum appliances. Am J Orthod Dentofac Orthop. 2009. 
20.  
S. Haydar, O. Uner. Comparison of Jones jig molar distalization appliance with 
extraoral traction. Am J Orthod Dentofacial Orthop. 2000. 
 
21.  
Hilgers JJ. The pendulum appliance for Class II non-compliance therapy. J Clin 
Orthod. 1992. 
22.  
Keles A. Unilateral distalization of a maxillary molar with sliding mechanics: A case 
report. J Orthod. 2002. 
23.  
Gelgör IE, Büyükyilmaz T, Karaman AIÝ, Dolanmaz D, Kalayci A. Intraosseous 
screw-supported upper molar distalization. Angle Orthod. 2004. 
24.  
Polat-Özsoy Ö. The Use of Intraosseous Screw for Upper Molar Distalization: A Case 
Report. Eur J Dent. 2008. 
25.  
Roberts WE, Marshall KJ, Mozsary PG. Rigid endosseous implant utilized as 
anchorage to protract molars and close an atrophic extraction site. Angle Orthod. 1990.  
26.  
Wehrbein H, Feifel H, Diedrich P. Palatal implant anchorage reinforcement of 
posterior teeth: A prospective study. Am J Orthod Dentofacial Orthop. 1999. 
27.  
De Clerck H, Geerinckx V, Siciliano S. The Zygoma Anchorage System. J Clin 
Orthod. 2002. 
28.  
Sugawara J, Kanzaki R, Takahashi I, Nagasaka H, Nanda R. Distal movement of 
maxillary molars in nongrowing patients with the skeletal anchorage system. Am J 
Orthod Dentofac Orthop. 2006. 
29.  
Park JH, Bayome M, Kook Y. Distalization of Maxillary and Mandibular Molars with 
TADs. In: Temporary Anchorage Devices in Clinical Orthodontics. ; 2020. 
30.  
Papadopoulos MA. Skeletal Anchorage in Orthodontic Treatment of Class II 
Malocclusion. J Orthod. 2015. 
31.  
Angle HE. TREATMENT OF MALOCCLUSION OF THE TEETH. ANGLE’S 
SYSTEM. S S WHITE Dent Manuf Co. 1907. 
32.  
Moyers RE, Riolo ML, Guire KE, Wainright RL, Bookstein FL. Differential diagnosis 
of Class II malocclusions: Part 1. Facial types associated with Class II malocclusions. 
Am J Orthod. 1980. 
33.  
Ghosh J, Nanda RS. Evaluation of an intraoral maxillary molar distalization technique. 
Am J Orthod Dentofacial Orthop. 1996. 
34.  
Pavlick CT. Cervical headgear usage and the bioprogressive orthodontic philosophy. 
Semin Orthod. 1998. 
35.  
Nur M, Bayram M, Celikoglu M, Kilkis D, Pampu AA. Effects of maxillary molar 
distalization with zygoma-gear appliance. Angle Orthod. 2012. 
 

 
25 
 
36.  
El-Dawlatly MM, Abou-El-Ezz AM, El-Sharaby FA, Mostafa YA. Zygoma-
Miniimplantate zur Korrektur von Klasse-II-Anomalien bei heranwachsenden 
Patientinnen. J Orofac Orthop. 2014. 
37.  
Nalcaci R, Kocoglu-Altan AB, Bicakci AA, Ozturk F, Babacan H. A reliable method 
for evaluating upper molar distalization: Superimposition of three-dimensional digital 
models. Korean J Orthod. 2014. 
38.  
Lemos LS, Rebello IMCR, Vogel CJ, Barbosa MC. Reliability of measurements made 
on scanned cast models using the 3Shape R700 scanner. Dentomaxillofacial Radiol. 
2015. 
39.  
Periago DR, Scarfe WC, Moshiri M, Scheetz JP, Silveira AM, Farman AG. Linear 
accuracy and reliability of cone beam CT derived 3-dimensional images constructed 
using an orthodontic volumetric rendering program. Angle Orthod. 2008. 
40.  
Kuroda, Sugawara, Deguchi, Kyung, Takano-Yamamoto. Clinical use of miniscrew 
implants as orthodontic anchorage: Success rates and postoperative discomfort. Am J 
Orthod Dentofac Orthop. 2007.