1. Volume 12 • Number 1
ORTHODONTICS
T e A n P a ce f
D nto cia
E ancemen
Formerly World Journal of Orthodontics
2. NEW TITLES FROM
Quintessence
Biomechanics
Orthodontics
Eiichiro Nakajima
Manual of Biomechanics
Wire Bending Orthodontics
IN
Techniques PRINCIPLES AND PRACTICE
IN
PRINCIPLES AND PRACTICE
Manual of Wire Bending Biomechanics in Orthodontics: Lingual Orthodontics: A New
Techniques Principles and Practice Approach Using STb Light Lingual
Eiichiro Nakajima Ram S. Nanda and Yahya Tosun System and Lingual Straight Wire
The authors of this step-by-step manual detail the Correct application of the principles of biomechanics Giuseppe Scuzzo and Kyoto Takemoto
essential components and techniques of customized leads to highly efficient orthodontic treatment. This
The authors detail the latest improvements in the
wire bending, including the first-, second-, third-, book introduces students of orthodontics to the evo-
STb light lingual system, such as improved patient
and fourth-order bends; selection and proper manip- lution of orthodontic technology and the properties
comfort, increased predictability of results, short-
ulation of pliers; and optimal methods of adjustment of orthodontic materials and outlines the essential
ened treatment times, and decreased laboratory
to be used during orthodontic treatment. mechanical principles behind successful orthodontic
work. The biomechanical benefits of the STb system
96 pp (spiral binding); 288 illus (117 color); treatment.
are also explained in full, including comprehensive
ISBN 978-0-86715-495-5 (B4955); US $85 168 pp; 350 illus (two-color); chapters on extractive and nonextractive mechanics,
ISBN 978-0-86715-505-1 (B5051); US $98 absolute anchorage control, low frictional force, and
the lingual straight-wire method.
264 pp; 885 illus (mostly color);
978-1-85097-192-4 (B8846); US $230
Pediatric Laser Dentistry: A User’s Guide Invisalign Orthodontic Treatment Handbook of Cephalometric
Giovanni Olivi, Fred A. Margolis, Richard Bouchez Superimposition
and Maria Daniela Genovese Herman S. Duterloo and
Pierre-Georges Planché
Esthetics, Growth, and Orthopedics of
Lingual and Esthetic Orthodontics the Face: Facial Development and
Edited by Rafi Romano Transformation in the Eye of the The Alexander Discipline, Volume 2:
Orthodontist and Other Beholders Building Facial Harmony and Stability
Joseph G. Ghafari R. G. “Wick” Alexander
Available Winter 2012
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3. ORTHODONTICS SPRING • 2011 TableofContents
T e A n P a ce f
Volume 12 • Number 1
D nto cia E ancemen ISSN 2160-2999 (print)
ISSN 2160-3006 (online)
Editorial 52
52
5 The relevance of orthodontic articles
Rafi Romano
Forewords
9 Ronald Goldstein/Michael Cohen
Scientific Innovation
10 Modification of the bidimensional system 62
Daniel J. Rinchuse/Donald J. Rinchuse
22 Posttreatment compliance with removable maxillary retention in
a teenage population: A short-term randomized clinical trial
Marc Bernard Ackerman/Barry Thornton
Technology
28 AUSOM: A 3D placement guide for orthodontic mini-implants
Mahmoud Al-Suleiman/Manal Shehadah
Controversy 74
38 Phantom bite: A survey of US orthodontists
Bozena B. Ligas/Maria Therese S. Galang/Ellen A. BeGole/
Carla A. Evans/Gary D. Klasser/Charles S. Greene
Interdisciplinary
48 A multidisciplinary approach to the treatment of a horizontally
impacted mandibular second premolar: 10-year follow-up
Dror Aizenbud/Liran Levin/Shaul Lin/Eli E. Machtei
Case Reports
60 Orthodontic management of an originally surgically planned
treatment of an open bite: A case report
Chadi Kassir/Samar Bou Assi
Practice Pearls
70 Dental amalgam corrosion in vacuum-formed retainers
Joseph R. Karam/Daniel J. Rinchuse
Treatment Planning Challenge
75 Missing maxillary lateral incisors: To close or to open?
Management
78 The dentist as a manager: Building effective relationships and
networks for personal and professional advancement
Hilla Dotan
Vignettes
82 Marc Bernard Ackerman
5. Editorial
The relevance of
orthodontic articles
I n recent years, orthodontic treatment
has become extremely common among
and accessible to a wide patient base.
In 1997, the World Federation of Orthodontists
commissioned a study of its affiliated organizations
for the purpose of gathering information about the global orthodontic com-
munity. The countries surveyed covered 54% of the world’s population, ac-
counting for nearly 3.3 billion people. The number of orthodontists was 31,000.
The highest ratios of orthodontists in relation to population (per 100,000
inhabitants) were found in North America, Central and South America, and
Europe (1.4 to 2.6).1
Today, with more than 70 accredited orthodontic postgraduate programs in
the United States and Canada, 12 in the United Kingdom, and many more in Asia
(in India, for example, about 300 new specialists in orthodontics graduate every
year), there is a growing number of faculty members (lecturers and professors) at
universities. The academic component for tenure and promotion compels these
orthodontists to write articles to be published in Medline-indexed journals, pref-
erably those with high impact factors. As a result, thousands of articles are sub-
mitted to orthodontic journals each year. Orthodontics receives about five new
submissions each week, or approximately 260 articles per year (meaning that
only one of every six submitted manuscripts will eventually be published).
Most of the articles are rejected, but many of those that are eventually pub-
lished have very little clinical significance. In vitro research with poor statis-
tics, clinical studies with minimal sample sizes, and conclusions that are not
evidence-based are part of every journal. At the same time, journal subscriber-
ship constantly decreases. In addition, the variety of free scientific and clinical
information online threatens the profitability of printed journals that are not
affiliated with professional societies or study clubs.
Our mission is to find a common denominator that will attract clinicians,
researchers, and postgraduate students. We have a commitment to stay
relevant, despite today’s tendency for instant messages and 140-character
“tweets.” Evidence-based information is the essence of scientific and clini-
cal articles. Even in countries where dental awareness is low, there is rising
interest in evidence-based dentistry (EBD).2 For EBD to become part of
decision making in practice, the most current and comprehensive research
findings must be translated into practice.3 We should focus on the take-
home message rather than satisfying the deans of faculties who quantify
the number of articles published as the essential requirement for academic
promotion. Barriers for implementation of research into practice primarily
include lack of interest, lack of involvement, lack of time, and lack of re-
muneration.4 As stated by David Turpin, the former editor of the American
Journal of Orthodontics and Dentofacial Orthopedics, as journal editors,
we have the tools and the responsibility to help readers identify the EBD
approach in each article.5
Volume 12, Number 1, 2011 5
6. Editorial
Along with my associate editor, Marc Bernard Ackerman, we have divided
the journal into 10 different sections, including the most innovative scientific
research, daily clinical pearls, updated technology, patient management tips,
“The 10,”
interdisciplinary case presentations, and treatment planning challenges, where
each orthodontist will find tips for more efficient and esthetic treatment results.
Our editorial board members, were carefully selected from all
around the world. They have a variety of clinical and scientific backgrounds and
are from private and university practices to ensure the relevance of Orthodontics
to 21st century demands.
I do hope you will enjoy the new concept and encourage your feedback and
submission of relevant articles. Together, we can make this journal an essential
clinical tool for the contemporary, evidence-based orthodontist.
Rafi Romano, DMD, MSc
Editor-in-Chief
rafi@drromano.com
RefeReNCeS
1. Waldman HB, Perlman SP, Schindel R.
Update on the imbalanced distribution of
orthodontists, 1995–2006. Am J Orthod
Dentofacial Orthop 2009;135:704–708.
2. Oladimeji Adeniyi A, Wasiu Lanre A.
Evidence-based dentistry in a developing
economy—The Nigerian example. Open
Dent J 2010;4:51–54.
3. Frantsve-Hawley J, Meyer DM. The
evidence-based dentistry champions:
A grassroots approach to the implemen-
tation of EBD. J Evid Based Dent Pract
2008;8:64–69.
4. Clarkson JE. Getting research into clinical
practice—Barriers and solutions. Caries
Res 2004;38:321–324.
5. Turpin DL. Consensus builds for evidence-
based methods. Am J Orthod Dentofacial
Orthop 2004;125:1–2.
6 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
7. ORTHODONTICS
T e A n P a ce f
D nto cia E ancemen
Editor-in-ChiEf AssoCiAtE Editor
rafi romano Marc Bernard Ackerman
Private Practice of Director of Orthodontics
Orthodontics Children’s Hospital Boston
Tel Aviv, Israel Boston, Massachusetts, USA
EditoriAL BoArd “The 10”
s. Jay Bowman Vittorio Cacciafesta Pablo Echarri Kurt faltin Jr nigel harradine
Private Practice Private Practice Private Practice Professor and Chair Consultant Orthodontist
Portage, Michigan Milan, Italy Barcelona, Spain Department of Bristol Dental Hospital
USA Orthodontics and School
University Paulista Bristol
São Paulo, Brazil United Kingdom
John C. Kois hee-Moon Kyung stephen rimer Maurice A. salama david sarver
Director and Founder Chair Private Practice Clinical Assistant Professor Private Practice
Kois Center Department of Boca Raton, Florida of Periodontics Birmingham, Alabama
Seattle, Washington Orthodontics USA University of Pennsylvania USA
USA Kyungpook National Philadelphia, Pennsylvania
University Medical College of Georgia
Daegu, Korea Augusta, Georgia, USA
Private Practice
Atlanta, Georgia, USA
8. ORTHODONTICS
T e A n P a ce f
• Abstract/key words. Abstracts should • Original articles are considered for
include a maximum of 250 words. publication on the condition they have
D nto cia E ancemen
Abstracts for Scientific Innovations not been published or submitted for
articles must be structured: Purpose, publication elsewhere.
Materials and Methods, Results, and • Manuscripts that are not prepared in
Conclusions. Abstracts for all other accordance with these guidelines will be
Guidelines For Authors types of articles that require one (see returned to the author before review.
description of 10 article categories) need • The editor and publisher reserve the right
ORTHODONTICS The Art and Practice of not be structured; these articles should to edit all manuscripts to fit the space
Dentofacial Enhancement (ORTHO) will also include up to 6 key words. available and to ensure conciseness,
consider for publication original articles on • Article text. See page limits for the 10 clarity, and stylistic consistency.
dentofacial enhancement that fall under the types of articles.
following 10 categories: • Acknowledgments. Persons who have ARTICLE ACCEPTANCE
made substantive contributions to the Article acceptance is pending receipt of
1. Editorial [Upon request only.] study can be acknowledged at the end images judged to be of sufficient quality
2. Technology [Latest innovation in of the article. Also specify grant or other for publication (see the guidelines below).
technology related to orthodontics. financial support, citing the name of Once a manuscript is accepted, authors
Abstract mandatory.] the supporting organization and grant should submit high-resolution digital image
3. Controversy [Controversial topics in number. files (on disk) to:
orthodontics. Pros and cons should be • Legends. Figure legends should
discussed. Abstract mandatory.] be typed as group at the end of the Managing Editor
4. Treatment Planning Challenge [Upon manuscript. Detailed legends are ORTHODONTICS
request only. No abstract required.] encouraged. For photomicrographs, Quintessence Publishing Co, Inc
5. Case Reports [Must include high- specify original magnification and stain. 4350 Chandler Drive
quality before and after photographs • Tables. Each table should be logically Hanover Park, IL 60133
with full description of treatment organized, typed on a separate page at
sequence. No abstract required.] the end of the manuscript, and numbered The disk/package should be labeled with
6. Scientific Innovations [Scientific consecutively. Table title and footnotes the first author’s name, shortened article
updates, research—in vivo and in vitro. should be typed on the same page as the title, and code number assigned upon
Abstract, discussion, and conclusions table. acceptance.
are mandatory.] • Abbreviations. The full term for which an
7. Practice Pearls [Tips and tricks for abbreviation stands should precede its DIGITAL IMAGE FORMAT
orthodontists’ daily work. Limit 4 first use in the text unless it is a standard When preparing final images to send,
pages. No abstract required.] unit of measurement. consider the following points:
8. Management [Practice management, • Trade names. Generic terms are to • Resolution must be at least 300 dpi when
marketing, and psychological aspects be used whenever possible, but trade the image is 3 inches wide.
of orthodontic treatment. Limit 6 names and manufacturer name, city, • Images saved in TIFF format are
pages. Abstract mandatory.] state, and country should be included preferred, but JPG or EPS files are
9. Interdisciplinary Advances [Cases parenthetically at first mention. acceptable.
and/or research with interdisciplinary • Images grouped together must be saved
orientation. All disciplines should REFERENCES as individual files.
be well presented in the article. No • All references must be cited in the text, • Images containing type should either be
abstract required.] numbered in order of appearance. saved as a layered file or provided along
10. Vignettes [Stories from the history of • The reference list should appear at the with a second file with type removed.
orthodontics, appliance invention, etc. end of the article in numeric sequence. • Line art (graphs, charts, line drawings)
Limit 4 pages. No abstract required.] • Do not include unpublished data should be provided as vector art
or personal communications in the (Illustrator or EPS files)
MANUSCRIPT SUBMISSION reference list. Cite such references • Please do not embed images into other
Submit manuscripts via ORTHO’s online parenthetically in the text and include a types of documents (eg, Word, Excel,
submission service: date. PowerPoint, etc).
www.manuscriptmanager.com/ortho • Avoid using abstracts as references.
Follow the simple step-by-step • Provide complete information for each MANDATORY SUBMISSION FORM
instructions. As the last step, you will reference, including names of all authors The Mandatory Submission Form
upload your manuscript, which should be a (up to six). If the reference is to part of a (accessible at www.quintpub.com) must
PC Word (doc) file with tables and figures book, also include title of the chapter and be signed by all authors and can be
included at the end of the document. names of the book’s editor(s). uploaded as a separate document with
the article submission, or it can be mailed
MANUSCRIPT PREPARATION Journal reference style: (see address above) or faxed (630-736-
• The journal will follow as much as 1. Pancherz H, Knapp V, Erbe C, Heis 3634) to the ORTHO Managing Editor.
possible the recommendations of the AM. Divine proportions in attractive
International Committee of Medical and nonattractive faces. World J PERMISSIONS AND WAIVERS
Journal Editors (Vancouver Group) in Orthod 2010;11:27–42. • Permission of author and publisher must
regard to preparation of manuscripts be obtained for the direct use of material
and authorship (Uniform requirements Book reference style: (text, photos, drawings) under copyright
for manuscripts submitted to biomedical 1. Sarver DM, Ackerman MB. Dynamic that does not belong to the author.
journals: http://www.icmje.org). smile visualization and quantification • Waivers must be obtained for
• Manuscripts should be typed in a and its impact on orthodontic diagnosis photographs showing persons.
12-point font and double-spaced. Pages and treatment planning. In: Romano R • Permissions and waivers should be faxed
should be numbered. (ed): The Art of the Smile. Chicago: along with the Mandatory Submission
• The first page(s) should include the title Quintessence, 2005:99–139. Form to the ORTHO Managing Editor
of the article and the complete names, (630-736-3634).
academic degrees, titles, professional REVIEW/EDITING PROCESS
affiliations, full addresses, faxes, and • Manuscripts will be reviewed by the REPRINTS
emails of all authors. The corresponding editors and reviewers with expertise in Reprints can be ordered from the
author should be clearly noted; if it is not, the field that encompasses the article. publisher. Authors receive a 40% discount
the first author will be assumed to be the • Reviews will be completed within 45 days on quantities of 100 or 200.
corresponding author. of article submission.
9. F
F wo ds
“
or the past several decades, our society has been preoccupied
with the subject of beauty and especially ways to make us all look
and feel better about ourselves. So I applaud the entrance of a
new journal devoted to the scienti c and artistic modalities to help patients
look and feel their best. Orthodontics has once again taken the lead in
convincing both the dental profession and the public of rst thinking of the
most ideal and long-lasting treatment to improve facial esthetics.
I was strongly in uenced by my uncle, Dr Marvin C. Goldstein, a brilliant
orthodontist who wrote one of the very rst extensive papers on treating the
adult patient. So my entire career has consisted of interdisciplinary consulta-
tions and treatment plans. Unfortunately, over the past decade, the subject
of esthetic compromise using porcelain laminates and other restorative so-
lutions has created many ongoing problems, resulting in esthetic failures
seen more and more throughout the world, when orthodontic treatment
would have been the ideal and most ef cient treatment plan. Therefore,
”
I welcome the new journal Orthodontics: The Art and Practice of Dentofacial
T
Enhancement and especially the most quali ed team of Ra and Marc at its
helm.
—Ronald Goldstein, DDS
“ he world of orthodontics has changed dramatically over the
past decade. The concept and practice of interdisciplinary team
treatment has opened up more opportunities for orthodontists
to participate in comprehensive case planning than ever before.
However, as both treatment planning and treatment have become increas-
ingly sophisticated, so too have the demands placed on orthodontists by pa-
tients and referring clinicians. Tooth position is only the starting point. In this
exciting new world of orthodontic possibilities, orthodontists by necessity must
have an even greater understanding of the various disciplines of dentistry.
When I became aware of the new direction that the World Journal of
Orthodontics was taking, I felt con dent that this new endeavor would bet-
ter meet the daily challenges that orthodontists face and, at the same time,
more effectively serve all dental disciplines. With new journal sections ad-
dressing topics such as clinical controversies, treatment planning challeng-
es, practice pearls, and management, I envision a publication which will
generate great appeal for clinical collaboration in the interdisciplinary team,
between study club members, and among dental colleagues.
I would like to congratulate Drs Ra Romano and Marc Ackerman for their
”
foresight, courage, and energy in introducing this highly relevant publica-
tion, Orthodontics: The Art and Practice of Dentofacial Enhancement, to our
profession.
—Michael Cohen, DDS, MSD
Volume 12, Number 1, 2011 9
10. Scientific
Innovation
Modification of the
bidimensional system
Daniel J. Rinchuse, DMD, MS, MDS, PhD1
Donald J. Rinchuse, DMD, MS, MDS, PhD2
In the mid 1970s, Schudy and Schudy developed and described an edgewise
bimetric system in which there were brackets with 0.016-inch slots on the
incisors and canines and brackets with 0.022-inch slots on the premolars
and molars. Modeling after Schudy and Schudy, Gianelly devised a similar,
preadjusted system called the bidimensional system, in which the incisor
brackets have 0.018-inch slots while the remaining teeth have brackets with
0.022-inch slots. We have further modified the bidimensional system and
developed a dual-slot system. Hence, this article compares the bidimensional
and dual-slot systems and provides justification for both. The main concerns
regarding the bidimensional and dual-slot systems are posterior “play”
and lack of three-dimensional control. We rationalize both as well as
the self-ligating hybrid and dual-slot system. ORTHO 2011;12:10–21.
Key words: bidimensional, bimetric, self-ligating, dual slot
1Professor and Associate
Director, Graduate
E
Program in Orthodontics, ven though straight-wire, or preadjusted, edgewise appliances have
Seton Hill University,
Greensburg, Pennsylvania, achieved universal acceptance, there has been little discussion of their
USA. clinical advantages in regard to treatment time, chair time, comfort, hy-
2Professor and Program
giene, or treatment results. As Harradine noted: “No study ever demonstrat-
Director, Graduate
Program in Orthodontics, ed that preadjusted edgewise appliances were superior to plain edgewise,
Seton Hill University, but the former are overwhelming preferred for reasons that are regarded by
Greensburg, Pennsylvania, clinicians as being self-evident and in no need of the highest order of scien-
USA.
tific proof.”1 In a retrospective study comparing the treatment results of Roth
CORRESPONDENCE (straight-wire) and standard edgewise appliances using two occlusal indices,
Dr Dan Rinchuse there were no significant differences found between the two appliances.2 In
510 Pellis Road
Greensburg, PA 15601 fact, despite using the Roth appliance, experienced orthodontists still found
Email: drinchuse@aol.com it difficult to obtain all six keys to normal occlusion.
10 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
11. To this juncture, the purpose of this article is not to demonstrate superior-
ity of a modified bidimensional system over other edgewise appliances, but
rather to justify our adaptations of Gianelly’s bidimensional system from a ra-
tionale viewpoint with the best available evidence.
bIMETRIC SySTEM
In the mid 1970s, Schudy and Schudy3 described and rationalized a fixed orth-
odontic appliance system that incorporated two bracket slot sizes, which they
called the bimetric system. It was a standard edgewise appliance system (zero
base) in which the incisors and canines had brackets with 0.016-inch slots and
the premolars and molars had brackets with 0.022-inch slots (Fig 1). They also
argued for what they called the precision-fit principle, meaning that in the fin-
ishing stages, the wires should fully engage the bracket slots, thus eliminating
or significantly reducing “play.” To fully engage and fill the dual-slot brackets,
a 0.016 × 0.022-inch stainless steel wire is twisted and torqued 90 degrees
distal to the canines. As a result, a ribbon archwire, 0.022 × 0.016-inch, is cre-
ated in the posterior segments.
bIDIMENSIONal SySTEM
Modeling after Schudy and Schudy, Gianelly4 developed a preadjusted, edge-
wise bidimensional system that had brackets with 0.018-inch slots on the inci-
sors and 0.022-inch slots on the canines, premolars, and molars (Fig 2).
Gianelly placed 0.022-inch slots on the canines, whereas Schudy and Schudy
had 0.016-inch slots on the canines. Gianelly made cogent arguments for
smaller bracket slots on the incisors (0.018 × 0.025-inch) for three-dimensional
control and a tight fit as well as for larger bracket slots (0.022 × 0.028-inch) on
Volume 12, Number 1, 2011 11
12. Scientific
Innovation
Modification of the bidimensional system
Schudy and Schudy Gianelly
0.016-inch 0.018-inch
0.022-inch 0.022-inch 0.022-inch 0.022-inch
0.022-inch 0.022-inch 0.022-inch 0.022-inch
0.016-inch 0.018-inch
Fig 1 (Left) Schudy and Schudy3 advocated brackets with 0.016-inch slots for the incisors and canines
(red) and brackets with 0.022-inch slots for the premolars and molars (green).
Fig 2 (Right) Gianelly’s bidimensional system4 uses brackets with 0.018-inch slots for the incisors
(blue) and brackets with 0.022-inch slots for the canines, premolars, and molars (green).
the posterior teeth and a loose fit for sliding mechanics and space closure (Fig 3).
(The terms tight fit and loose fit were descriptions used by Gianelly.)
Gianelly gave the following justifications for his bidimensional system: “The
reason I did this was to combine precision with practicality. For example, one
movement that requires torque control is the retraction of the maxillary incisors.
In the edgewise technique, full engagement of the wire in the incisor brack-
ets is generally necessary to control the axial inclination of the incisors during
retraction. I use a 0.018 × 0.025-inch vertically slotted, programmed bracket
on the central and lateral incisors and a 0.022 × 0.028-inch vertically slotted
bracket posteriorly. For retraction, I simply insert a 0.018 × 0.022-inch wire for
full engagement of the incisor brackets and retract the incisors bodily by means
of sliding mechanics, because the wire is ’undersized‘ in the buccal segments.
According to a New York University study, only 7% of wires ’fill the slots.’ My
percentage during incisor retraction approaches 100%. The undersized poste-
rior part of the wire also relieves me of the technical burden of adjusting the
torque to the posterior brackets. My chair time is reduced, and I don't have to
contend with loops that may impinge on the tissues.”5
Gianelly pointed out that few orthodontists fill the edgewise slots, especially
for 0.022-inch slot users, so this is support for at least full 3D control of the inci-
sors with 0.018 × 0.022-inch or 0.018 × 0.025-inch stainless steel archwires.
For space closure, by sliding, Gianelly’s working wires are 0.016 × 0.022-inch
12 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
13. Scientific
Innovation
Rinchuse and Rinchuse
0.018 0.018
0.022-inch 0.018-inch
Fig 3 Brackets with (right) 0.018 × 0.025-inch incisor slots and
(left) 0.022 × 0.028-inch posterior slots. With a 0.018 × 0.022-inch
stainless steel working wire for sliding space closure, the incisor
brackets are filled, while in the posterior brackets, the wire is un-
dersized for reduced resistance to sliding.
stainless steel or 0.018 × 0.022-inch stainless steel with crimp-on hooks distal
to the lateral incisor brackets and closed nickel-titanium (Ni-Ti) coils attached
to the crimp-on and molar hooks. He made an important point that for space
closure, 0.017 × 0.025-inch or 0.018 × 0.025-inch stainless steel wires are not “
Resistance to sliding is
simply a combination of
classical friction and a
coefficient of binding.
”
viable substitutes for the 0.016 × 0.022-inch or 0.018 × 0.022-inch stainless
steel wires because the horizontal dimension of 0.025 inches creates too much
resistance to sliding for space closure. Resistance to sliding is simply a combi-
nation of classical friction and a coefficient of binding. In fact, Gianelly typically
advocated using rectangular wires throughout treatment.
Nonetheless, a criticism of the bidimensional system is a lack of 3D control
with full-sized 0.018 × 0.025-inch wires in the incisors but undersized in the
posterior teeth due to the 0.022-inch slot. Gianelly’s counter was the same as
Schudy and Schudy: To fill the posterior bracket slots, twist a 0.018 × 0.022-inch
stainless steel wire 90 degrees distal to the lateral incisors and create a rib-
bon arch with 0.022 × 0.018-inch stainless steel wire in the posterior. However,
twisting or torquing a wire 90 degrees is cumbersome and unconventional for
most orthodontists. Another option is to bend custom torque into rectangular
archwires, as is traditionally done. Be that as it may, these solutions for lack of
3D control has never impressed orthodontists enough to adequately justify the
bidimensional system. This in part may account for why only 4.7% of responding
orthodontists reported routinely using the bidimensional system.6
Volume 12, Number 1, 2011 13
14. Scientific
Innovation
Modification of the bidimensional system
Table 1 Comparison of the various slot sizes from a perspective of space closure
(assuming sliding mechanics) and torque control
Slot size advantages Disadvantages
0.018-inch slot Anterior torque control: Full 3D control with Space closure: Lighter undersized stainless steel
0.018 × 0.025-inch archwires wires more prone to deformation and notching
0.022-inch slot Space closure: Larger, stiffer undersized stain- Torque control: Full-sized 0.022 × 0.028-inch
less steel wires, less deformation and notching archwires are too stiff to be used so undersized
finishing wires must be used
Bidimensional Space closure: Larger, stiffer undersized
(dual-slot) 0.018- and rectangular wires (0.016 × 0.022- or 0.018 ×
0.022-inch slots 0.022-inch), less deformation and notching with
0.022-inch slots in posterior teeth, and effective
3D control of incisors during space closure with
0.018-inch slot in the anterior.
Anterior torque control: Full 3D control with Possible loss of posterior 3D control with
0.018 × 0.025-inch archwires full-sized 0.018 × 0.025-inch archwires
(counterarguments made in this article)
MODIFICaTION OF THE bIDIMENSIONal SySTEM:
THE Dual-SlOT SySTEM
Having worked with Gianelly’s bidimensional system for over 20 years, we have
developed some conceptual and mechanical alterations, which, for communi-
cation purposes, we will call the dual-slot system. It must be noted, however,
that Gianelly deserves the credit for providing the foundation and framework
for our modification of the bidimensional system.
Proffit et al7 argued the advantages and disadvantages of the 0.018-inch
slot vs the 0.022-inch slot from the perspective of sliding mechanics and
torque control (Table 1). For instance, Proffit et al7 stated that sliding teeth
along an archwire necessitates at least 2 mil (0.002-inch) of clearance—
4 mil (0.004-inch) of clearance is desirable. So, with this principle, the ad-
vantage of a 0.022-inch slot would be that larger 18 mil (0.018-inch) wires
could be used (compared to 16 mil [0.016-inch] wires in an 0.018-inch slot).
Therefore, larger, stiffer wires would have fewer tendencies for notching
and deformation. So, specifically for space closure by sliding, it would be
advantageous to have brackets with 0.022-inch slots posterior to the ex-
traction spaces for a looser fit, reduced resistance to sliding, and the use
of stiffer wires.
However, for torque control in the incisors, it is better to have brackets with
0.018-inch slots because full-sized wires can be engaged if full 3D control is
necessary. A 0.022-inch slot would not be advantageous for torque control
since full-sized 0.022 × 0.028-inch wires are too stiff to be engaged into the
bracket slots. Therefore, using Proffit et al’s7 rationalization, a bidimensional
system would integrate the best of both the 0.018-inch and 0.022-inch slot
systems: a tight fit in the incisors for full 3D control and a loose fit elsewhere
for space closure by sliding. As an aside, various studies have shown that treat-
ment times are shorter8–10 and outcomes may be better with a 0.018-inch slot
compared to a 0.022-inch slot.8
14 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
15. Scientific
Innovation
Rinchuse and Rinchuse
In regard to criticism of play or lack of 3D control in the posterior segments
with the bidimensional or dual-slot system, as a conceptual difference, we
have never twisted a 0.018 × 0.022-inch stainless steel wire distal to the lateral
incisors in an attempt to enhance 3D control in the posterior, as advocated by
Gianelly and Schudy and Schudy. If most orthodontists using a 0.022-inch slot
finish with 0.019 × 0.025-inch wires,11 a full-sized 0.018 × 0.025-inch wire in
a bidimensional or dual-slot system is not much different. Customized torque
can still be used in the posterior segments if necessary.
Furthermore, it has been shown that there is tremendous morphologic vari-
ability in the facial surfaces of teeth.12–15 Specifically, Germane et al12 reported
the greatest variability in the posterior teeth. Even a very slight difference in
bracket height placement, as little as 1 mm, could alter tooth inclination as
much as 10 degrees.12 Creekmore and Kunik16 elaborated on this argument
and showed that variations in tooth structure, such as variable facial surfaces,
crown-root angulations, and atypical crown shape, warrant variations in tip,
torque, rotation, and height parameters to obtain optimal results for each tooth.
In reference to a recent article by Mulligan,17 which differentiated the mo-
ments created with full vs partial appliances, Keim18 noted that “one of the
most common mistakes that arises as a result of standardized treatment proto-
cols is the tendency to place full appliances in every case. Not only is this un-
necessary in many patients, but if we analyze the resulting force systems, it may
actually be contraindicated.” Furthermore, Mulligan19 often avoided bracket-
ing the premolars and sometimes canines so that these teeth could be used to
gauge whether the arches are expanding or constricting. Some have called this
the neutral zone: equilibrium between lips, cheeks, tongue, and muscle forces
exerted on teeth, particularly in the buccal segments, and the preexisting buc-
cal segments may be in their most stable functional environment.
In reference to the “equilibrium effects on the dentition,” Proffit et al20 stat-
ed that although masticatory forces are much stronger, the lighter pressures
of the lips, cheeks, and tongue are much greater in duration, and these pres-
sures, even at rest, are sustained most of the time and affect tooth position. To
demonstrate this, they described the case of a woman who has tremendous
unilateral splaying of the left posterior and anterior teeth subsequent to loss
of lip and cheek pressure due to an infection and paralysis, with resulting pro-
“
nounced tongue pressure. Arguing for a new soft tissue paradigm over the old
“Angle ideal dental occlusion” paradigm, Profitt et al20 showed evidence for
the new model. For instance, in regard to stability of results, the old model was
related primarily to dental occlusion, whereas the new model relates stability Some have called
primarily to soft tissue pressure and equilibrium effects. Therefore, soft tissue this the neutral zone:
balance and equilibrium even after teeth are moved orthodontically will influ-
ence tooth position. So, even if you have a prescription in your appliance that
equilibrium between
results in a certain 3D position of the teeth, the patient’s oral environment may lips, cheeks, tongue,
provide the ultimate stable position of the dentition. and muscle forces
For these reasons and others, in the finishing stage of treatment, some or-
thodontists use lighter wires, anterior segmental archwires and no posterior
exerted on teeth,
archwires with or without vertical elastics, circumferential retainers, and canine- particularly in the
to-canine vacuum-formed retainers to permit posterior settling. Again, the 3D buccal segments,
control of the posterior segments that the orthodontist strived to obtain may
be altered with settling and equilibrium of soft tissue on the teeth. Interesting-
and the preexisting
ly, Lyotard et al21 demonstrated the results of removing final archwires at the buccal segments
end of active orthodontic treatment for 4 weeks. Mandibular crowding, over- may be in their most
”
jet, and interproximal contacts worsened; however, marginal ridges, occlusal
contacts, and total American Board of Orthodontics scores improved. Assum-
stable functional
ing that anterior segmental archwires are left intact, the authors concluded that environment.
Volume 12, Number 1, 2011 15
16. Scientific
Innovation
Modification of the bidimensional system
their study supports the practice of removing the archwires from the posterior
teeth a few weeks prior to debonding for settling and improved occlusion.
If orthodontists using 0.022-inch slot appliances finish with 0.019 × 0.025-inch
stainless steel wires,11 it may be argued that these orthodontists have play
throughout their system, whereas the dual-slot system has play only in the pos-
terior and complete control of anterior teeth with full-sized 0.018 × 0.025-inch
finishing wires. With play in the posterior and complete control in the anterior,
teeth may level and align faster and space closure may be enhanced because of
reduced resistance to sliding in the posterior segments.
If inclination/torque is dynamic and changes in the posterior, particu-
larly the molars, over time as Marshall et al22 demonstrated, one might
consider two possibilities: custom torque for each patient or to simply use
the same for each patient. With normal, transverse growth of the max-
illary and mandibular first molars from age 7.5 to 26.4 years, the maxillary
molars upright lingually 3.3 degrees. Maxillary intermolar width increases
2.8 mm, and the mandibular molars upright 5.0 degrees and mandibular inter-
molar width increases by 2.2 mm. Therefore, an attempt to prescribe a static
facial torque in the buccal segments may ultimately be altered by growth or
settling of the occlusion over time. So one may facetiously ask whether varying
posterior 3D prescriptions for patients depending on their age is necessary.
Another critical question is whether specific, ideal torque values are any
healthier than others. Is there morbidity generally associated with malocclusion?
Ackerman and Proffit stated, “Although the concept of ideal occlusion has taken
precedence as the ultimate goal in clinical orthodontics for some 110 years and
serves well as an adopted arbitrary convention and a clinical gold standard, it
has no verifiable scientific validity. No one has yet demonstrated that ideal occlu-
sion provides significant benefits in oral or general health or that it significantly
improves oral function.”23 Research seems to support Ackerman and Proffit’s po-
sition. For instance, malocclusion is generally not associated with temporoman-
dibular disorders (TMD), and orthodontics cannot lessen or prevent the future
development of TMD.24–28 Contrary to what may seem reasonable, a recent sys-
tematic review29 identified an absence of reliable evidence describing the posi-
tive effects of orthodontic treatment on periodontal health. In fact, orthodontic
therapy results in small detrimental effects to the periodontium: alveolar bone
loss, gingival recession, and increased periodontal pocket depth.
Another point is related to the issue of expansion. Interestingly, many advo-
cates of arch development and upright mandibular posterior teeth have inclination
(lingual crown torque) prescriptions of –25 or –30 degrees, not –12 or –15, for the
mandibular first molars. It is possible that expanded archwires may override the
built-in prescription of –25 or –30 degrees and produce upright molars.30
Another difference in biomechanics between our system and Gianelly’s is
that for space closure, Gianelly4 generally advocated separately retracting ca-
nines and then the four incisors. On the contrary, our system employs en masse
“
retraction for the the six anterior teeth, except for cases of anterior arch-length
discrepancies or crowded anterior teeth, such as lingually blocked lateral inci-
. . . an attempt to sors. Then, we separately retract the canines only to relieve crowding. This treat-
prescribe a static ment philosophy is also held by Burstone, who said: “Since relatively low forces
are capable of retracting six teeth, there is little logic to separate retraction of
facial torque in the canines followed by retraction of the four incisors. For that reason, only patients
buccal segments may who have anterior arch-length problems with anterior crowding require separate
ultimately be altered canine retraction.”31 This would prevent round-tripping teeth.
”
This is supported by Heo et al,32 who found no significant difference in
by growth or settling of posterior anchorage loss between en masse retraction of the six anterior teeth
the occlusion over time. and separate, two-step retraction of the canines followed by the four incisors;
16 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
17. Scientific
Innovation
Rinchuse and Rinchuse
Table 2 Comparison of the differences between Gianelly’s bidimensional technique
and the dual-slot system
Comparisons bidimensional technique Dual-slot system
Canine vs en masse Canine retraction En masse retraction except for anterior
retractions arch-length discrepancies
Initial wires Generally rectangular Generally round
Vertical slots Yes, for auxiliaries, and uprighting springs in No
canines for anterior labial forces in the mandibu-
lar arch in Class II extraction cases to prevent an
overjet with intra-arch mechanics
Ball hooks No Yes, on most teeth
Bracket torque No posterior torque More torque on anteriors and posterior torque
Rationalization for Twist a 0.018 × 0.022-inch stainless steel wire Can place conventional torque in archwires
lack of 3D control in 90 degrees distal to the lateral incisors to create a More variability of facial surfaces in the
posterior teeth ribbon arch posterior teeth
Mulligan Mechanics —generally premolars and
sometimes canines are not bracketed, especially
with use of V-bends
Neutral zone
With growth, molars tend to upright
Self-ligation model No Propose dual-slot self-ligating and hybrid
self-ligating models
two-step retraction took longer. Likewise, Xu et al,33 in a randomized clinical
trial comparing en masse and two-step retraction in 64 growing boys and girls
with Angle Class I and II malocclusions requiring maxillary premolar extractions
and maximum anchorage using an MBT prescription and 0.022 × 0.028-inch
bracket slots, headgear, and some transpalatal appliances, found that contrary
to what some clinicians believe, two-step retraction is not more effective than
en masse retraction in preventing clinically meaningful anchorage loss. And,
again, two-step retraction lengthens treatment time.
As an example, if you want to close maxillary first premolar extraction spaces
by 8 mm, assume that you can close the space 1 mm per month for a total of 8
months to retract the canines and then another 8 months to retract the incisors.
However, if you retract the six anterior teeth en masse, you can close the space
in 8 months, saving 8 months of treatment. Moreover, a recent study concluded
that there should be no expected difference in external apical root resportion
between two-step and en masse space closure procedures.34
As mentioned previously, Gianelly routinely used rectangular wires throughout
treatment, whereas our initial wires are generally round Ni-Ti wires, as advocated
by Proffit. For instance, Proffit et al7 state that, “A tightly fitting resilient rect-
angular archwire for initial alignment is almost always undesirable because not
only is frictional resistance to sliding likely to be problematic, the wire produces
back-and-forth movement of the root apices as the teeth move into alignment.”
With moderate to severely rotated teeth, resilient round wires would offer
another advantage because they have flexibility in both the horizontal and ver-
tical dimensions, whereas resilient rectangular wires have more flexion in the
vertical dimension and limited flexion in the horizontal dimension. Table 2 is
an overall comparison of differences between the Gianelly bidimensional tech-
nique and the dual-slot system.
Volume 12, Number 1, 2011 17
18. Scientific
Innovation
Modification of the bidimensional system
Table 3 Summary of the possible hybrid or dual-slot self-ligating
systems adapted after Rinchuse and Miles35
bracket system Slot size (inches) active Passive
Hybrid self-ligating 0.018-inch 0.018 Anterior Posterior
Hybrid self-ligating 0.022-inch 0.022 Anterior Posterior
Dual-slot self-ligating 0.018 Anterior
0.022 Posterior
Dual-slot self-ligating active 0.018 Anterior
0.022 Posterior
Dual-slot self-ligating passive 0.018 Anterior
0.022 Posterior
SElF-lIGaTION: FuTuRE HybRID aND Dual-SlOT
SElF-lIGaTING SySTEMS
Rinchuse and Miles35 described a hybrid self-ligating bracket systems in either
entirely 0.018-inch slots or entirely 0.022-inch slots in which the anterior brack-
ets are active with a spring clip and the posterior brackets have a passive slide,
very similar to a bimetric, bidimensional, or dual-slot system. Since the gingival
horizontal wall is compromised by an obliquely inclined spring clip, the ac-
tive self-ligating brackets are smaller than their conventional counterparts and
not truly 0.018 × 0.025- or 0.022 × 0.028-inch. Therefore, this hybrid system
“
would have so-called reduced bracket slots in the anterior for a tighter fit and
enhanced 3D control, especially with undersized 0.019 × 0.025-inch stainless
steel finishing wires in 0.022-inch slots, and a looser fit with possibly reduced
With moderate to resistance to sliding with passive brackets36–38 in the posterior for leveling,
severely rotated teeth, alignment, and space closure.
resilient round wires In an in vitro study, Badawi et al39 found that active self-ligating brackets
are more effective in torque expression than passive self-ligating brackets in
would offer another 0.022-inch slots and 0.019 × 0.025-inch stainless steel wire. Likewise, if many
advantage because orthodontists use a 0.022-inch slot and only finish with 0.019 × 0.025-inch stain-
they have flexibility in less steel wire,11 it might be desirable to use an active self-ligating system since
there may be more enhanced 3D control and dental esthetics of the incisors.
both the horizontal and However, if a clinician is filling the 0.018-inch bracket slots with 0.018 × 0.025-
vertical dimensions, or 0.0175 × 0.025-inch finishing wires, a passive self-ligating system might be
whereas resilient advantageous, possibly reducing resistance to sliding in the initial stages of
treatment. However, this is controversial, with notching and binding as variables
rectangular wires have affecting resistance to sliding.40
more flexion in the To obtain excellent 3D control in the anterior teeth and at the same time
vertical dimension and have even more reduced resistance to sliding in the posterior, a dual-slot self-
”
ligating system can be used with active 0.018-inch slot anterior brackets and
limited flexion in the passive 0.022-inch slot posterior brackets. Other self-ligating permutations are
horizontal dimension. all-active or all-passive dual-slot systems. Table 3 codifies the possible hybrid
18 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
19. Scientific
Innovation
Rinchuse and Rinchuse
Dual-slot system (different slot sizes, but same self-ligating brackets)
• 0.018-inch slots on the anterior teeth and 0.022-inch slots on the posterior teeth
• Conventional
• Active self-ligating
• Passive self-ligating
Hybrid system (same slot size, but different self-ligating brackets)
• Mimics a bidimensional or dual-slot system
• Active anterior and passive posterior self-ligating brackets
• Stays in the same slot size (0.018- or 0.022-inch)
Dual-slot–hybrid system (different slots and different self-ligating brackets
[active and passive])
• 0.018-inch slot anterior brackets and 0.022-slot posterior brackets
• Active anterior brackets and passive posterior brackets
Fig 4 The various permutations of self-ligating systems.
and dual-slot self-ligating systems. Figure 4 shows the permutations of ma-
nipulating slot size, active or passive self-ligating brackets, and a hybrid system
(same slot size but active anterior and passive posterior brackets).
Paik et al41 applied the principles that Rinchuse and Miles35 developed to
describe a hybrid bracket-tube system called the hybrid sliding mechanics of
low friction, which is a combination of passive self-ligating brackets on the pre-
molars, conventional tubes on the molars, and conventional twin brackets on
the anterior teeth. However, much of the rationale for this system is based on
in vitro data regarding friction and passive self-ligating brackets.
CONCluSION
We have presented a cursory review of the bimetric and bidimensional systems
juxtaposed with a dual-slot system that offers an alternative to Gianelly’s sys-
tem. Furthermore, we codified Rinchuse and Miles’35 thoughts on hybrid and
dual-slot self-ligating systems.
aCKNOWlEDGMENTS
Since we were orthodontic residents at the University of Pittsburgh in 1974, we have been
impressed with Dr Anthony Gianelly’s (1936–2009) research, articles, and particularly his bi-
dimensionsal system. He was a very unassuming and humble man. We have used a bidimen-
sional prescription that we have modified for over two decades, which this paper addresses.
However, without Tony’s concepts and principles, this paper would not have been possible.
Volume 12, Number 1, 2011 19
20. Scientific
Innovation
Modification of the bidimensional system
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Mosby, 2007:376, 553. Dentofacial Orthop 2002;121:93–96.
8. Detterline DA, Isikbay SC, Brizendine EJ, 25. American Academy of Pediatric Dentistry
Kula KS. Clinical outcomes of 0.018-inch Conference. Treatment of temporoman-
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2010;80:528–532. Dent Assoc 1990;120:265–269.
9. Vu C, Roberts WE, Hartsfield JK Jr, Ofner 26. Gesch D, Bernhardt O, Kirbschus A. Asso-
S. Treatment complexity index for assess- ciation of malocclusion and functional oc-
ing the relationship of treatment duration clusion with temporomandibular disorders
and outcomes in a graduate orthodontics (TMD) in adults: A systematic review of
clinic. Am J Orthod Dentofacial Orthod population-based studies. Quintessence
2008;133:9.e1–9.e13. Int 2004;35:211–221.
10. Amditis C, Smith LF. The duration of fixed 27. Mohl ND. Temporomandibular disorders:
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of two groups of patients treated using tronic devices. A diagnostic update. J Am
edgewise brackets with 0.018” and 0.022” Coll Dent 1991;58:4–10.
slots. Aust Orthod J 2000;16:34–39. 28. McNeill C, Mohl ND, Rugh JD, Tanaka TT.
11. Sheridan JJ. The reader’s corner. J Clin Temporomandibular disorders: Diagnosis,
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12. Germane N, Bentley BE Jr, Isaacson J Am Dent Assoc 1990;120:253–257.
RJ. Three biologic variables modifying 29. Bollen AM, Cunha-Cruz J, Bakko DW,
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Orthop 1989;96:312–319. systematic review of controlled evidence.
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in tooth morphology and bracket position 32. Heo W, Nahm DS, Baek SH. En masse
on first and third order correction with retraction and two-step retraction of
preadjusted appliances. Am J Orthod maxillary anterior teeth in adult Class I
Dentofacial Orthop 1999;116:329–335. women. A comparison of anchorage loss.
16. Creekmore TD, Kunik RL. Straight wire: Angle Orthod 2007;77:973–978.
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20 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
21. Scientific
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Rinchuse and Rinchuse
33. Xu TM, Zhang X, Oh HS, Boyd RL, Korn 38. Matarese G, Nucera R, Militi A, et al.
EL, Baumrind S. Randomized clinical trial Evaluation of frictional forces during
comparing control of maxillary anchorage dental alignment: An experimental model
with 2 retraction techniques. Am J Orthod with 3 nonlevel brackets. Am J Orthod
Dentofacial Orthop 2010;138:544. Dentofacial Orthop 2008;133:708–715.
e1–544.e9. 39. Badawi H, Toogood RW, Carey JPR, Heo
34. Huang Y, Wang XX, Zhang J, Liu C. G, Major PW. Torque expression of self-
Root shortening in patients treated with ligating brackets. Am J Orthod Dentofa-
two-step and en masse space closure cial Orthop 2008;133;721–728.
procedures with sliding mechanics. Angle 40. Shoaf S. JCO Interviews Dr William Proffit
Orthod 2010;80:492–497. on the present and future of orthodontics.
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ets: Present and future. Am J Orthod 41. Paik CH, Ahn HW, Yang IH, Baek SH.
Dentofacial Orthop 2007;132:216–222. Low-friction space closure with a hybrid
36. Henao SP, Kusy RP. Evaluation of the bracket-tube system. J Clin Orthod
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e15–187.e24.
Volume 12, Number 1, 2011 21
22. Scientific
Innovation
Posttreatment compliance with
removable maxillary retention in a
teenage population: A short-term
randomized clinical trial
Marc Bernard Ackerman, DMD, MBA1
Barry Thornton, EdD2
Removable retainer wear is most related to patient comfort and acceptance.
Patient compliance is essential for retention and maintenance of the orthodontic
treatment results. Even though patients are educated about the need for
prolonged retention after active treatment and asked to sign informed
consent regarding the risk of noncompliance (relapse) prior to treatment, most
orthodontists would estimate that at least half of their teenage patients do
not comply at optimal levels. The aim of the present study was to quantify
teenage patient compliance with removable maxillary retention and compare
actual usage vs prescribed usage between subjects who knew they were
being monitored via an implanted microsensor in the retainer and those
subjects who were unaware of any monitoring. The final sample consisted of
9 subjects in the test group (5 males and 4 females) and 10 subjects in the
control group (4 males and 6 females). The evidence suggests that individuals
who were made aware of the orthodontist’s ability to monitor compliance
wore the device for a significantly larger number of hours per day than those
who were unaware of this fact. Patients reporting full usage of the retainer
wore the appliance a mean of 4.3 hours more per day than those reporting
less than full usage, holding all other variables constant. Patients who
misrepresented their retainer use (reported full usage but wore the device less
than 19 hours per day) wore the appliance a mean 12.4 hours less than the
more honest patients who participated in the study. ORTHO 2011;12:22–27.
1Formerly, Chair and
Program Director,
Jacksonville University
School of Orthodontics, Key words: orthodontic retention, compliance, microsensor
Jacksonville, Florida,
O
USA; currently, Director of rthodontics is concerned with variations in dentofacial traits that may
Orthodontics, Children’s
Hospital Boston, Boston, affect an individual’s overall well-being. Dentofacial traits are defined
Massachusetts, USA. as hard or soft tissue characteristics or combinations of characteristics
2Professor, Department of
that distinguish an individual’s facial appearance and determine their level
Economics, Jacksonville
University, Jacksonville, of oral and social function. Orthodontic intervention includes therapies that
Florida, USA. enhance dentofacial traits, thus improving a person’s health.1 Contemporary
orthodontic treatment is a two-step process: active treatment and retention.
CORRESPONDENCE
Dr Marc Bernard Ackerman Active treatment involves modification of tooth position via fixed applianc-
Children’s Hospital Boston es or removable clear aligners. Retention refers to the period of supervised
300 Longwood Ave maintenance of the teeth in their corrected positions via retainers after active
Boston, MA 02115
Email: marc.ackerman@ treatment. Of all the dentofacial traits, tooth alignment is most affected by a
childrens.harvard.edu patient’s compliance with retention.
22 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
23. Nearly a century ago, Norman Kingsley stated, “The success of orthodontia
as a science and an art now lies in the retainer.”2 To date, there is little con-
sensus in the orthodontic literature on the most effective retention strategy in
clinical practice.3 However, many orthodontists concur that retention is abso-
lutely necessary for three principal reasons: (1) gingival and periodontal tissues
are affected by orthodontic tooth movement and require time for reorganiza-
tion when active appliances are removed4; (2) teeth may be in an inherently un-
stable position after active treatment, such that soft tissue pressure constantly
produces a relapse tendency; and (3) changes produced by growth may alter
treatment results in growing subjects.5 Reorganization of the periodontal liga-
ment (PDL) occurs over a 3- to 4-month period after active appliance removal.4
Reorganization of the collagenous and elastic fibers in gingivae occurs more
slowly than that of the PDL.6 The collagenous fiber networks within gingivae
complete their reorganization within 4 to 6 months after removal of active
appliances. The elastic supracrestal fibers remodel very slowly and can exert
forces capable of tooth movement even 1 year after active appliance removal.
There is tremendous variation in retention protocols used in contemporary
orthodontic practice. However, there is general agreement among orthodon-
tists that regardless of the length of the supervised retention period or the
prescribed daily schedule of retainer wear, patients must have some type of
retention following active treatment to maintain treatment results. Although
data in the scientific literature are scant, some authors have suggested that
retention appliances be placed immediately after the active appliances are
removed,4 worn full-time (except during meals) for the first 3 to 4 months after
active appliance removal, and then worn part-time for 1 or 2 years thereafter.5
In practice, most orthodontists develop their own retention protocol based
either on what they were taught in residency or their clinical experience after
some years of practice.
Removable retainer wear is most related to patient comfort and acceptance.7
Patient compliance in retention is essential for maintenance of the orthodontic
result. Although subjects are educated about the need for prolonged retention
after active treatment and are asked to sign an informed consent form regard-
ing the risk of noncompliance (relapse) prior to treatment, most orthodontists
estimate that at least half of their teenage patients comply below optimal lev-
els. Noncompliant patients experience a relapse of tooth crowding or spacing
within the first few months of retention. Patients who do not comply properly
in the initial retention period are at risk for significant relapse in the long term.
With no way of determining whether patients follow the prescribed plan of
retention, orthodontists have been unable to assess whether changes in tooth
position are a result of poor retainer compliance or ineffective retainer design.
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24. Scientific
Innovation
Posttreatment compliance with removable maxillary retention in a teenage population
Table 1 Study criteria
Inclusion criteria Exclusion citeria
• Subjects aged between 13 and 19 years • Phase I–treated patients
• Treatment plan includes maxillary Hawley • Craniofacial syndromes
retainer use • Poor compliance during active orthodontic
• No history of retainer wear treatment (such as multiple missed
• No missing anterior teeth requiring appointments or excessive appliance
pontic teeth on the retainer breakage)
• Ideal alignment of maxillary anterior teeth
at debonding
“ There is tremendous variation in retention
protocols used in contemporary orthodontic
practice. However, there is general agreement
among orthodontists that regardless of the
length of the supervised retention period or
the prescribed daily schedule of retainer wear,
patients must have some type of retention
”
following active treatment to maintain
treatment results.
This inability to accurately monitor or police patient retainer compliance has
also negatively affected patient motivation during this important phase of treat-
ment. A new methodology for incorporating a microsensor to quantify patient
compliance was published in the orthodontic literature.8
The aim of the present study was to quantify teenage patient compliance
with removable maxillary retention and compare actual vs prescribed usage
between subjects who knew they were being monitored via a microsensor
in the retainer and those subjects who were unaware of any monitoring. The
null hypothesis was that there was no difference in retainer usage between
those subjects who knew they were being monitored and those subjects
who were unaware of it.
METHODS
Once study approval from the Jacksonville University Institutional Review
Board was granted, patients approaching the end of fixed appliance ther-
apy who met the inclusion and exclusion criteria (Table 1) were invited to
participate in the study. Written informed consent was obtained from each
patient or patient’s parent or guardian prior to the initiation of retention,
and subjects were free to withdraw at any time during the study.
24 ORTHODONTICS The Art and Practice of Dentofacial Enhancement
25. Scientific
Innovation
Ackerman and Thornton
Fig 1 The USB-powered sensor reader with a study retainer in the
reading position.
Twenty-three subjects were recruited. Subjects were randomly assigned to
the test (aware of monitoring) or control group (unaware of monitoring). The
test group initially consisted of 11 subjects (5 males and 6 females) with a
mean age of 15.4 years; the control group initially consisted of 12 subjects
(5 males and 7 females) with a mean age of 15.6 years. Each subject received a
maxillary Hawley retainer constructed of wire and pink orthodontic acrylic with
a blue microsensor embedded in the middle of the palatal acrylic. The word
“smart” was stamped on the sensor and visible through the acrylic (Fig 1). All
subjects were asked to wear the appliance at all times, with the exception of
during meals and contact sports (approximately 20 hours per day) for the first
month after fixed appliance therapy.
Subjects were recalled 1 month after debonding. Retainer compliance was
calculated using the methodology described in a previous publication.8 Sub-
jects were asked to subjectively rate their compliance with the prescribed hours
of retainer wear. Three options were given: (1) worn as prescribed, (2) moder-
ately worn (at least half of the time), and (3) poorly worn (less than half of the
time). Four subjects dropped out of the study: Three subjects lost their retain-
ers in the first month after debonding, and one patient’s microsensor malfunc-
tioned. The final sample consisted of 9 subjects in the test group (5 male and
4 female) and 10 subjects in the control group (4 male and 6 female).
Volume 12, Number 1, 2011 25
