The document summarizes current evidence from studies on different approaches to treating class II malocclusions, including: 1) Early treatment vs one-phase treatment during adolescence. High quality studies show early treatment does not provide advantages over one-phase adolescent treatment. 2) Treatment during adolescence with functional appliances or headgear vs untreated controls. Functional appliances are effective at reducing overjet but do not fully correct skeletal discrepancies. 3) Incremental vs maximum advancement with functional appliances. High quality studies found no advantages of one approach over the other.

1. ‫الرحيم‬‫الرحمن‬‫هللا‬‫بسم‬
University of Khartoum
Faculty of Dentistry
Department of Orthodontics
Current evidence regarding
functional appliance treatment of
class II malocclusion
Mohanad Elsherif
BDS (U of K), MFD RCSI, MFDS RCPS(Glasg), MSc (Orthodontics), M.Orth. RCSEd

2. Current evidence regarding
functional appliances
 Dilemmas regarding treatment of skeletal
problems:
 Growth modification Vs camouflage Vs Surgery
 One phase Vs two phase treatment.
 Fixed Vs removable functional appliances.
 Incremental Vs Maximum mandibular advancement.
 Full-time Vs Part-time wear of functional appliance.

3. Current evidence regarding
functional appliances
 We will based our discussion on three questions:
 Should we provide treatment when the child is in the early transitional
dentition as a phase I treatment with a functional appliance or headgear,
followed by a phase II course of treatment when the child is an adolescent?
 If a decision is made to wait until the child is in adolescence, should we
provide treatment with a functional appliance or headgear to attempt to
modify the growth or alternatively carry out treatment to correct the
overjet using fixed appliances?
 Should we carry out a treatment at all in adolescence compensating for
skeletal discrepancies or perhaps wait until the child ’ s jaw growth is
almost complete and then provide orthognathic surgical treatment?

4. 1. Early Vs late treatment
 Treatment involves intervention when the child is in the early
mixed dentition (8 – 10 Years) as (phase I) followed by a second
course of treatment when they are in early adolescence (phase II),
with the aim of “ intercepting ” a developing Class II malocclusion.
 Why early treatment?
 This early intervention normalizes the skeletal pattern.
 It Reduces the length of any subsequent phase II treatment.
 Or at least it makes further treatment simpler by reducing the need for
extractions.

5. 1. Early Vs late treatment
Harrison , J.E. , O’Brien , K.D. & Worthington , H.V. , 2007 . Orthodontic treatment for
prominent upper front teeth in children . Cochrane Database Systematic Reviews CD003452.
 The authors systematically searched the literature confining the search to
randomized and controlled trials that evaluated treatment to correct
prominent incisors.
 They were specifically interested in the outcome measures of incisor overjet,
skeletal relationship, self - esteem, and any possible harms as a result of
treatment.
 After exclusions, they identified four trials concerned with early treatment
for children aged 8 – 10 years. They classified the trials according to their
setting as follows: Florida, North Carolina, New Zealand, and UK.

6. 1. Early Vs late treatment
 All four studies were concerned with a comparison of active early
treatment with an untreated control group.
 The Florida, North Carolina, and the UK study all followed the
patients through to the conclusion of all orthodontic treatment;
however, the New Zealand study only followed the patients to the
conclusion of phase I.
 The Cochrane Review reported a meta - analysis that was carried
out at the end of phase I and at the end of phase II.

7. 1. Early Vs late treatment
 The four studies all used slightly different treatment
protocols for phase I treatment:
 The UK group used a Twin Block or Herbst as the active intervention.
 The New Zealand group used a Frankel or a Harvold appliance.
 Florida evaluated two interventions, cervical pull headgear/biteplane
combination and a bionator
The North Carolina group evaluated cervical pull headgear and
Bionator.

8. 1. Early Vs late treatment
 The results of these four high - quality studies are very similar
and clinically important:
 Modest improvement in the skeletal relationship (1.3 degree)
 Marked difference in incisor prominence ( − 4.0 mm)
 Similarly, the use of headgear resulted in small differences in ANB ( −
0.72 degrees) and overjet ( − 1.0 mm).
 The UK - based study also showed an increase in self - esteem for the
treatment group.

9. Phase 1
1. Early Vs late
treatment

10. 1. Early Vs late treatment
Not So Fast?

11. 1. Early Vs late treatment
 Three of the trials were extended to follow the patients through to the
conclusion of orthodontic treatment.
 A meta - analysis was carried out for final overjet, skeletal pattern, occlusal
alignment, incisal trauma, and self – esteem
 They concluded that:
“all the treatment was effective, in that incisor prominence had been reduced.
Nevertheless, there were no differences in treatment outcome between the groups of
children who had received one or two phases of treatment. As a result, it appears that
two - phase treatment does not have any advantages over one phase treatment”.
 i.e. There is strong evidence that early treatment does not have any advantages
over treatment that is provided in one phase during adolescence, apart from a
transient increase in self - esteem.

12. 2. One phase treatment during
adolescence
 Choices:
 Functional appliance and/or headgear.
 Fixed appliances only.
 Any combination of the these methods.

13. The updated review (2018)
Batista KBSL, Thiruvenkatachari B, Harrison JE, O’Brien KD. Cochrane Database of Systematic
Reviews 2018, Issue 3. Art. No.: CD003452. DOI: 10.1002/14651858.CD003452.
 They tried to answer three main questions:
1. What are the effects of treatment provided in 1 or 2 phases
(early vs adolescent)?
2. What are the effect of later treatment with functional appliances
vs untreated controls?
3. Are there any difference in the effects of the various types of
functional appliance?
 Primary outcome was overjet. Secondary was skeletal
relationship, harms, self esteem.

14. The updated review (2018)
Early treatment
 When treatment was provided early the only effect of treatment
was a 12% reduction in the incidence of incisal trauma.
 At the end of all treatment 19% of the early treatment group had
experienced trauma. Whereas, 31% of those that did not have
early treatment had trauma.
 There were no effects of early treatment on final occlusion, self
esteem and skeletal pattern.

15. Early Vs late treatment
 Based on these results early treatment should not be routinely
prescribed for patients with large overjet's, but may be considered
if the patient is either being harmed due to excessive teasing at
school, or has a sufficiently large overjet (or lifestyle) that makes
them at a serious risk of significant trauma.

16. The updated review (2018)
Late treatment
 Low-quality evidence suggests that, compared to no treatment,
late treatment in adolescence with functional appliances, is
effective for reducing the prominence of upper front teeth.
 It was clear that the functional appliances reduced the overjet of
the patients (-4.62mm – -5.46mm)
 Removable functional appliances statistically reduced the ANB by
2.37 degrees

17. 3. Incremental Vs Maximum
Advancement of Functional
Appliances
 When a functional appliance is prescribed for a patient,
we have the choice of activating the appliance to either
maximum advancement or in increments of a few
millimeters.
 There are differing opinions as to the advantages and
disadvantages of these two approaches, and until recently
these opinions were based entirely on clinical opinion.

18. 3. Incremental Vs Maximum
Advancement of Functional
Appliances
 Advantages of incremental advancement:
 Improved speech and patient comfort
 Facial esthetics
 Patient compliance
 More effective because muscle adaptation
 Advantages of maximum advancement:
 Increased orthopedic effect
 Less appliance modification is needed

19. 3. Incremental Vs Maximum
Advancement of Functional
Appliances
Banks , P. , Wright , J. & O’Brien , K. , 2004 . Incremental versus maximum bite advancement
during twin – block therapy: a randomized controlled clinical trial . American Journal
Orthodontics and Dentofacial Orthopedics 126 , pp. 583 – 588 .
 203 patients were randomized to receive Twin Block treatment with
either maximum advancement or advancement in 2 - mm increments.
 They evaluated the effect of the two different treatment methods on
(1) completion rate.
(2) final skeletal pattern.
(3) duration of treatment.
 No differences in these outcome measures between the two groups of
patients.

20. 3. Incremental Vs Maximum
Advancement of Functional
Appliances
Gill , D.S. & Lee , R.T. , 2005 . Prospective clinical trial comparing the effects of conventional
Twin -block and Mini - block appliances: part 1. Hard tissue changes . American Journal of
Orthodontics and Dentofacial Orthopedics 127 , pp. 465 – 472 , quiz p. 517 .
 70 patients were randomly allocated to receive treatment with either
a maximally advanced Twin Block or with a Mini - Block appliance
 The latter appliance was a modified Twin Block with smaller blocks at
90 degrees to each other and advanced in 3 - mm increments.
 They carried out a complex analysis of many cephalometric
measurements, and they concluded that there were no real advantages
of incremental over maximum advancement and vice versa.

21. 3. Incremental Vs Maximum
Advancement of Functional
Appliances
Conclusion:
 It appears that both of these studies were in
agreement and there is no advantage or disadvantage
for either method of advancement of Twin Blocks.

22. 4. Fixed Vs removable functional
appliance
Pacha M. Fleming P & Johal. A comparison of the efficacy of fixed versus removable functional
appliances in children with Class II malocclusion: A systematic review. Eur J Orthod (2016) 38
(6): 621-630.
 This review only included randomized or nonrandomized trials.
 They carried out a systematic review to high standards and they clearly
stated the PICO.
Participants: Children less than 16 years old with Class II malocclusion
Interventions: Any type of fixed functional appliance
Comparison: Any type of removable functional appliance
Outcome measures: The primary outcomes were measures of skeletal,
dentoalveolar and soft tissue correction.

23. 4. Fixed Vs removable functional
appliance
Results
 Four studies met the final inclusion criteria, three studies were at
high risk of bias and one was unclear.
 They concluded that all the variations of functional appliance
successfully reduced the overjet to normal limits. There were also
minor skeletal changes but as these were not compared to an
untreated control group, we cannot, therefore, make any conclusions
on whether the appliances changed the skeletal pattern more than
normal growth.

24. 4. Fixed Vs removable functional
appliance
O’Brien , K. , Wright , J. , & Conboy , F. , 2003c . Effectiveness of treatment for Class II
malocclusion with the Herbst or Twin - block appliances: a randomized, controlled trial .
American Journal of Orthodontics and Dentofacial Orthopedics 124 , pp. 128 – 137 .
A. In term of completion rate:
 There was only one study that compared the relative completion rates
of fixed and removable functional appliances, and this revealed that
noncompletion for a Herbst appliance was 13% and for the Twin Block
was 33%.
 A more recent study by Lee et al. (2007) has revealed that the
noncompletion rate in a trial of the Dynamax and Herbst appliances was
9% for both appliances.

25. 4. Fixed Vs removable functional
appliance
O’Brien , K. , Wright , J. , & Conboy , F. , 2003c . Effectiveness of treatment for Class II
malocclusion with the Herbst or Twin - block appliances: a randomized, controlled trial .
American Journal of Orthodontics and Dentofacial Orthopedics 124 , pp. 128 – 137 .
B. Patient Perceptions
 The only study that collected information on the way that the patients felt
about their appliances was the UK study comparing the Twin Block and Herbst
appliances.
 In this study, the investigator gave the patients a short questionnaire that
sought information on how their appliances influenced factors such as school
work, family life, ease of speaking, and interference with homework.
 The results were interesting in that the patients felt that the Twin Block was
worse than the Herbst with respect to influence on eating, speaking, and
discomfort, and they reported more embarrassment with their friends and
families.

26. 4. Full-Time Vs Part-time wear of
functional appliance
Jeet Parekh, Kate Counihan, Padhraig S. Fleming, Nikolaos Pandis, and Pratik K. Sharma.
Effectiveness of part-time vs full-time wear protocols of Twin-block appliance on dental and
skeletal changes: A randomized controlled trial. Am J Orthod Dentofacial Orthop 2019;155:165-72
 Aim Compare the dental and skeletal effects of Twin Block wear when prescribed for either
full or part-time wear
 They did a parallel group randomized trial with a 1:1 allocation. The PICO was:
Participants: Class II Division 1 patients aged 11-13 years old with overjets greater than 7mm.
Intervention: Advice to wear Twin Block part-time for a total of 12 hours a day.
Control: Advice to wear Twin Block full-time, except for eating and sport. (22 hours a
day).
Outcome: Primary outcome was overjet reduction. Secondary outcomes cephalometric
skeletal change.

27. 5. Full-Time Vs Part-time wear of
functional appliance
 The mean overjet reduction in the full-time group was 7mm
(SD=2.92) and 6.5mm (SD=2.62) in the part-time group. These
differences were not clinically or statistically significant.
 They also found no differences in the anteroposterior
skeletal measurements (ANB change for the part-time group
was 1.5 degrees and 1.25 degrees for the full-time group).
 “There are no differences in skeletal and dental changes
between full and part-time wear of a Twin Block”

28. Final conclusions and Evidence
1. The provision of early orthodontic treatment with either functional
appliances or headgear does not achieve the aims of reducing treatment
time, reducing extractions, and improving skeletal pattern when
compared to single – phase treatment in adolescence.
2. While there may be some beneficial effect on a child ’ s self - esteem,
there are no significant differences ultimately in self - esteem between
those children who have received two phases of treatment and those
treated in one phase in adolescence.
3. Two - phase treatment undoubtedly involves more appointments,
increased duration of overall treatment with all the associated risks, and
increased cost to the health - care system or the individual.

29. Final conclusions and Evidence
4. When we consider treatment that is provided in adolescence, there
appears to be some orthodontic growth modification from the use of a
functional appliance, but the majority of the change is dentoalveolar.
The use of headgear also provides limited skeletal change, and the
greatest effect is dentoalveolar, with “ distal ” molar movement of up to
2 mm. Importantly, on average, this is not sufficient to correct a full -
cusp Class II molar relationship.
5. It appears that with all functional appliance treatment, the average
failure rate is about 20%. This should be considered when this treatment
is offered to a patient, and it should be explained to the parents and the
patients that only four out of five of these treatments will succeed.
Unfortunately, there is no comparable data for headgear
noncompliance.

30. Final conclusions and Evidence
6. When we consider patient values, it is fair to suggest that patients
prefer fixed functional appliances as opposed to the Twin Block because
of problems that arise from the bulky bite blocks. Furthermore, the
cooperation rate with the fixed appliance appears to be greater. These
appliances are, however, significantly more expensive, and cost should
be considered in our discussions with patients and parents.
7. The main unanswered and important question concerns the
effectiveness of providing treatment in adolescence versus orthognathic
surgery when the patient is older. There is clearly a need for well -
designed studies in the future to resolve this important question.

31. Declaration
 The author wish to declare that; these presentations are his original work, all
materials and pictures collection, typing and slide design has been done by the
author.
 Most of these materials has been done for undergraduate students, although
postgraduate students may find some useful basic and advanced information.
 The universities title at the front page indicate where the lecture was first
presented. The author was working as a lecturer of orthodontics at Ibn Sina
University, Sudan International University, and as a Master student in Orthodontics at
University of Khartoum.
 The author declare that all materials and photos in these presentations has been
collected from different textbooks, papers and online websites. These pictures are
presented here for education and demonstration purposes only. The author are not
attempting to plagiarize or reproduced unauthorized material, and the intellectual
properties of these photos belong to their original authors.

32. Declaration
 As the authors reviews several textbooks, papers and other references during
preparation of these materials, it was impossible to cite every textbook and journal
article, the main textbooks that has been reviewed during preparation of these
presentations were:
Contemporary Orthodontics 5th edition; Proffit, William R, Henry W. Fields, and
David M. Sarver.
Handbook of Orthodontics. 1st edition; Cobourne, Martyn T, and Andrew T. DiBiase.
Clinical cases in orthodontics; Martyn T. Cobourne, Padhraig S. Fleming, Andrew T.
DiBiase, Sofia Ahmad
Essentials of orthodontics: Diagnosis and Treatment; Robert N. Staley, Neil T. Reske
Orthodontics: Current Principles & Techniques 5th edition; Graber, Lee W, Robert L.
Vanarsdall, and Katherine W. L. Vig
Evidence based Orthodontics; Greg J. Huang, Stephen Richmond, Katherine W.L. Vig.

33. Declaration
 For the purposes of dissemination and sharing of knowledge, these
lectures were given to several colleagues and students. It were also
uploaded to SlideShare website by the author. Colleagues and students
may download, use, and modify these materials as they see fit for non-
profit purposes. The author retain the copyright of the original work.
 The author wish to thank his family, teachers, colleagues and students
for their love and support throughout his career. I also wish to express
my sincere gratitude to all orthodontic pillars for their tremendous
contribution to our specialty.
 Finally, the author welcome any advices and enquires through his
email address: Mohanad-07@hotmail.com

34. Thank you