A COMPARISON OF SKELETAL AND DENTAL CHANGES IN PATIENTS WITH A CLASS II RELATIONSHIP TREATED WITH CLEAR ALIGNER MANDIBULAR ADVANCEMENT AND HERBST APPLIANCE FOLLOWED BY COMPREHENSIVE ORTHODONTIC TREATMENT-AJODO 2024

29/07/2025 1
A COMPARISON OF SKELETAL AND DENTAL CHANGES IN
PATIENTS WITH A CLASS II RELATIONSHIP TREATED WITH
CLEAR ALIGNER MANDIBULAR ADVANCEMENT AND HERBST
APPLIANCE FOLLOWED BY COMPREHENSIVE ORTHODONTIC
TREATMENT-AJODO 2024
P R E S E N T E D B Y
D R A N U R A G
P G F I N A L Y E A R
G O V T D E N T A L C O L L E G E J A M M U

29/07/2025 2
ABOUT JOURNAL
Name of the journal : AMERICAN JOURNAL OF ORTHODONTICS &
DENTOFACIAL ORTHOPAEDICS. (Ajodo 2024)
The journal is abstracted and indexed in CINAHL,index
medicus/MEDLINE/pubmed, and scopus.
Impact factor: 3(2025)
Editor in chief – Rolf g. Behrents

29/07/2025 3
ABOUT AUTHORS
Hamid Reza Hosseini-Private practice, Vancouver, British Columbia, Canada
Peter Ngan-Department of Orthodontics, School of Dentistry, West Virginia University,
Mor gantown, W Va.
Sandra Khong Tai-Department of Orthodontics, School of Dentistry, University of
British Columbia, Vancouver, British Columbia, Canada.
Lee J. Andrews, II-Private practice, Augusta, Ga.
Jun Xiang-Department of Family Medicine, School of Medicine, West Virginia
University, Morgantown, W Va.

29/07/2025 4
CONTENTS
 Introduction
 Materials & Methods
 Results & Discussion
 Conclusion
 Related Articles

29/07/2025 5
INTRODUCTION
Class II malocclusions can result from a protruded maxilla, retruded mandible, or
both, and may be influenced by cranial base length or vertical growth patterns.
Increased anterior facial height and a steep occlusal plane can rotate the mandible
backward, worsening the Class II profile.
Management options include growth modification, camouflage, and surgery.

29/07/2025 6
Growth modification is most effective 1–2 years before the growth peak.
Headgear and functional appliances help guide skeletal development.
Functional appliances reposition the mandible, stimulate condylar growth, and
address habits like lip traps.
They also protect protruded incisors and enhance facial esthetics

29/07/2025 7
Functional appliances can be removable or fixed.
Invisalign with Mandibular Advancement (MA) is a clear aligner with precision wings designed
to mimic removable functional appliances.

29/07/2025 8
The Herbst appliance is a fixed functional appliance with telescopic arms that
continuously posture the mandible forward.
It allows natural jaw movement and is cemented to the teeth.

29/07/2025 9
This study aims to compare skeletal and dental effects of Invisalign MA and the Herbst appliance
in Class II treatment

29/07/2025 10
MATERIALS & METHODS
INCLUSION CRITERIA
The inclusion criteria consisted of consecutively treated patients with a skeletal Class II malocclusion with an
ANB angle of >/=4deg ; mandibular plane angle of <40deg ; and lateral cephalometric radiographs taken
before treatment (T1) immediately after the advancement phase(T2);and after completion of second phase
treatment(T3).

29/07/2025 11
EXCLUSION CRITERIA
Exclusion criteria included patients with Class II Division 2 malocclusion, those past the peak
puberty growth spurt or above cervical vertebral stage ,missing radiographs, diagnosed with
medical conditions or syndromes, congenitally missing teeth, or not completing treatment.

29/07/2025 12
Sample Size:
•20 patients in each group: 20 MA and 20 Herbst patients.
•Total sample = 40 patients.
Matching Criteria:
•Patients were matched based on:
•Skeletal maturation (using CVM – Cervical Vertebral Maturation stages).
•Craniofacial morphology (overall jaw and face structure).
Gender Distribution:
•Each group had:
•9 males
•11 females

29/07/2025 13
CVM Stage Distribution (for skeletal maturity)
•3 patients at CS2
•4 at CS3
•13 at CS4
•This distribution was equal in both groups (Herbst and MA).
Age:
•Herbst group: 12.7 ± 1.8 years
•MA group: 13.1 ± 1.5 years

29/07/2025 14
Purpose:
To ensure that the same examiner gives consistent results when evaluating patients at different times —
this is called intrarater (intraexaminer) reliability.
Cephalometric Superimposition:
10 patients randomly selected from each group (Herbst and MA) → total of 20 patients.
Their lateral cephalograms (side-view x-rays of the skull) were:
◦ Traced and superimposed twice
◦ With a 2-week gap between the two sessions.
This was done to check how consistent the examiner was with landmark identification and
tracing

29/07/2025 15
Skeletal Maturation (CVM Index):
Skeletal age was assessed using the Cervical Vertebral Maturation (CVM) index.
The examiner scored CVM stages for all patients.
The same scoring was repeated after 2 weeks to verify consistency in assessment.

29/07/2025 16
Intrarater reliability testing helps ensure that:
•The examiner’s measurements are not changing over time.
•The data (landmarks and skeletal age) are reliable and reproducible.
•This is essential in clinical studies to ensure that results are valid, especially when
subjective assessment (like tracing landmarks) is involved

29/07/2025 17
HERBSTAPPLIANCE DESIGN & CLINICAL PROTOCOL
Appliance Source:
•Herbst appliance used was from Specialty Appliances,
Cumming, Georgia.
Pre-Insertion Steps:
•Brackets placed on maxillary incisors.
•Sectional wire used for initial alignment of anterior teeth.

29/07/2025 18
Modifications for Comfort and Function:
•Transpalatal arch removed to improve patient comfort.
•Buccal archwire tubes with telescoping mechanism used:
•Replaced traditional rods and tubes.
•Prevented impingement on the ascending ramus (a known drawback of older Herbst designs).

29/07/2025 19
Maxillary Arch Expansion (if required):
Expansion screw added when needed.
Activated at a rate of 0.25 mm/day until desired expansion was reached

29/07/2025 20
Mandibular Advancement Protocol:
Initial advancement of 3 mm.
Followed by gradual increments of 1–2 mm every 2 months.
Continued until achieving a negative overjet of 1–2 mm (edge-to-edge or slight anterior crossbite to
encourage mandibular adaptation).

29/07/2025 21
COMPREHENSIVE FIXED APPLIANCE PHASE (AFTER HERBST REMOVAL)
Brackets Used:
•GAC mini twin brackets, 0.022-inch slot, bonded on all teeth.
Archwire Sequence:
Maxillary Arch:
•0.014-inch NiTi (for initial alignment).
•0.016-inch Stainless Steel (SS).
•0.019 × 0.025-inch NiTi (rectangular wire for torque control).
•0.018 × 0.025-inch SS (for final leveling and finishing).

29/07/2025 22
Mandibular Arch:
•0.014-inch NiTi.
•0.016 × 0.022-inch NiTi.
•0.020-inch SS.
•0.018 × 0.025-inch SS.
Treatment Goals & Completion Criteria:
Achieved a Class I buccal occlusion.
Maxillary and mandibular arches well aligned.
Normal overbite and overjet established

29/07/2025 23
INVISALIGN WITH MANDIBULARADVANCEMENT (MA) PROTOCOL
Treatment Start and Criteria:
MA treatment was done using Invisalign with MA (precision wings).
Advancement started after specific corrections depending on initial
malocclusion:
◦ Deep overbite ≥8 mm → required leveling of curve of Spee.
◦ Overjet <2 mm in Class II Division 2 → required proclination of maxillary
incisors.
◦ Posterior crossbite → maxillary arch expanded using aligners.
◦ Severely rotated maxillary molars → corrected before mandibular
advancement.

29/07/2025 24
Mandibular Advancement Phase:
Mandible advanced 2 mm every 8 weeks, until edge-to-edge incisor contact achieved.
Alignment involved first premolar to first premolar in both arches.
Curve of Spee was leveled by intruding mandibular anterior teeth.
No interproximal reduction (IPR) done during this phase.
Expansion and proclination were the primary mechanisms for alignment.

29/07/2025 25
Post-Advancement Phase:
After reaching edge-to-edge incisor relation, patients were rescanned for the second set of
aligners (without MA wings).
Additional aligners used for final alignment and detailing.
Use of Class II Elastics:
Precision cuts provided in aligners for Class II elastics (full- or part-time use).
Used if:
◦ Further improvement of molar relationship was needed.
◦ In asymmetrical cases, the less severe side was corrected to Class I first.

29/07/2025 26
Final Corrections:
Remaining Class II relations corrected via:
◦ Maxillary molar distalization.
◦ Or Class II elastic simulation jump.
If mandibular incisors were proclined during advancement, 0.2 mm IPR prescribed to retrocline them.
Treatment Completion Goals:
Class I buccal occlusion.
Well-aligned maxillary and mandibular arches.
Normal overbite and overjet achieved.

29/07/2025 27
CEPHALOMETRIC ANALYSIS AND RELIABILITY METHODOLOGY
Radiograph De-Identification and Organization:
Each patient was assigned a random number and initials to de-identify data.
Files were created in Dolphin Imaging Software (v11.7) under mock patient names.
Three time points were defined per patient:
◦ T1 – Start of treatment
◦ T2 – End of appliance phase
◦ T3 – End of comprehensive treatment
`

29/07/2025 28
Custom Cephalometric Analysis:
Radiographs were traced using a custom cephalometric analysis in Dolphin software.
The analysis included variables from:
◦ Pancherz
◦ Bjork
◦ VanLaecken et al
◦ Wigal et al

29/07/2025 31
Measurement Details:
Each variable was measured twice to assess consistency.
Linear and vertical measurements: to the nearest 0.1 mm.
Angular measurements: to the nearest 0.1°.

29/07/2025 32
Reference Grid for Superimposition:
Sagittal skeletal and dental changes were measured:
◦ Along the occlusal plane (OL) and occlusal plane perpendicular (OLp).
The T1 cephalogram served as the baseline to create the reference grid.
This grid was transferred to T2 and T3 images by superimposing on midsagittal cranial
structures.

29/07/2025 33
Outcome Assessment
Changes in overjet and molar relationship were analyzed to determine:
Skeletal vs. dental contributions to treatment changes.
1) 0lp-A-pt : Skeletal –position of maxilla relative to
occlusal line perpendicular
2) Olp- pg–Skeletal –position of mandible ( pogonion )
relative to occlusal line perpendicular
3) Olp-A-pt minus Is /Olp –Upper incisor position
relative to maxilla
4) Olp –pg minus li /Olp-Lower incisor position relative to
mandible

29/07/2025 34
•The study followed a rigorous and standardized cephalometric protocol, ensuring:
•High accuracy of measurements.
•Strong reliability and reproducibility through repeated tracings and ICC.
•The combination of multiple landmark systems (Pancherz, Bjork, etc.) provides a
comprehensive view of both skeletal and dental changes.

29/07/2025 35
RESULTS & DISCUSSION
The final sample consisted of 20 patients treated with the Herbst appliance, matched with 20 patients treated
with the MA appliance.
No significant differences were found in skeletal maturation or CVM stage between the Herbst (3.50 +/-
0.76) and the MA group (3.50 +/- 0.76).

29/07/2025 36
CRANIOFACIAL MORPHOLOGY COMPARISON AT T1 (START OF TREATMENT)
Mandibular Position (Skeletal)
MA group had a more retrusive mandible:
MA: 75.4°
Herbst: 78.4°
Interpretation: The MA group started with a more backward-
positioned mandible, suggesting slightly more skeletal Class II
discrepancy at baseline

29/07/2025 37
Mandibular Incisor Inclination (Dental)
MA group had more proclined lower incisors:
◦ MA: 101.8°
◦ Herbst: 94.6°
Interpretation: The MA group had dentally compensated
for the skeletal discrepancy through proclination of
mandibular incisors, which is common in Class II cases.

29/07/2025 38
Although the groups were well matched in skeletal maturity, there
were initial anatomical differences:
•MA group had a more retrusive mandible (possibly more severe
skeletal Class II).
•MA group had more proclined lower incisors, likely due to natural
or prior dental compensation.
These differences may influence:
•The mechanism of correction (skeletal vs dental).
•The treatment response to each appliance.

29/07/2025 39
The average treatment duration with the MA appliance was 14.4 months, followed by 17.9 months of
treatment with clear aligners, giving an overall treatment duration of 32.3 months.
The average treatment duration for the Herbst appliance was 18.5 months, followed by 18.3 months of
treatment with a fixed appliance of 18.3 months, giving an overall treatment duration of 36.8 months.

29/07/2025 40
Herbst Appliance Treatment Changes (T2 – T1)
Statistical Significance:
19 out of 25 variables showed significant changes from
T1 to T2 (based on matched paired t-tests).
Indicates the Herbst appliance had a strong effect on
craniofacial structures during the active phase.

29/07/2025 42
SAGITTAL CHANGES – OVERJET REDUCTION
Total overjet correction: 4.8 mm
This includes overcorrection (intentionally going edge-to-edge or beyond).

29/07/2025 43
Contribution to Overjet Correction:
Skeletal: 4.2 mm (88%)
Dental: 0.6 mm (12%)
The majority of overjet correction was skeletal, especially due to mandibular advancement.
Minimal incisor movement means the appliance acted primarily by modifying jaw position, not just
teeth

29/07/2025 44
Molar Relationship Correction:
Total molar correction: 6.4 mm
🔹 Breakdown of contributing factors:
Contribution to Molar Correction:
•Skeletal: 4.2 mm (52%)
•Dental: 2.2 mm (48%)
Molar correction was half skeletal and half dental, showing a balanced mechanism:
•Forward movement of the mandible played a major skeletal role.
•Molar movements (distal and mesial shifts) also significantly contributed.

29/07/2025 45
The Herbst appliance produced substantial skeletal effects, particularly:
•Mandibular advancement leading to overjet and molar correction.
•Dental changes were limited but supportive, especially with molar movements.
•Confirms that Herbst is effective as a growth-modifying appliance, especially during active
growth periods

29/07/2025 46
For vertical changes with the Herbst appliance, significant changes were found with a 1.4 mm downward
movement of A point, a 2.1 mm increase in lower face height (ANS-Me), 0.9 mm decrease in mandibular
incisor eruption (li-ML); 3.3 mm reduction in overbite, and 1.8 mm eruption of the mandibular molars.
For angular changes with the Herbst appliance, there was a 0.9degree decrease in SNA, 0.9degree increase
in SNB, and 1.8 degree change in ANB.
The occlusal plane was tipped 3.0 degree clockwise; maxillary incisors were retracted 6.8degree , and
mandibular incisors were proclined 8.7degree .

29/07/2025 47
FINAL HERBST GROUP CHANGES (T1–T3)
Total overjet correction: 2.7 mm

29/07/2025 48
Molar Correction - -4.2mm

29/07/2025 49
•The majority of overjet and molar correction was due to
skeletal changes, especially mandibular advancement.
•There was some relapse of the incisors after Herbst
overcorrection, reducing the net overjet change.
•Molar correction was a mix of skeletal shifts and dental
movements, typical in comprehensive orthodontic
treatment.

29/07/2025 50
For vertical changes with Herbst and fixed appliance (T3- T1),significant changes were found
with a 1.0mm downward movement of A point, 3.2 mm increase in lower face height (ANS-Me),
2.4 mm decrease in overbite, and 2.8mm eruption of mandibular molars.
For angular changes, there was a 1.2 decrease in SNA, 1.7degree decrease in ANB,0.8 degree
tipping of the palatal plane, 2.9degree tipping of the occlusal plane, and 4.4 degree Proclination
of the mandibular incisors.

29/07/2025 52
MAWITH CLEARALIGNERS – TOTALTREATMENT EFFECTS (T3 – T1)
Total overjet reduction: 2.8 mm
Overjet correction was mainly skeletal, with minimal dental
movement. Unlike Herbst, MA resulted in retraction of both
sets of incisors (rather than proclination of lowers), likely due
to controlled tooth movement with aligners.

29/07/2025 53
Molar Correction:4mm
Molar correction was mostly skeletal, but dental movements
played a meaningful role through molar distalization and
mesialization

29/07/2025 54
HERBST VS MA APPLIANCES – KEY DIFFERENCES

29/07/2025 55
COMPARISONAT T3–T1 (TOTALTREATMENT EFFECTS)
•MA showed slightly greater condylar movement in the long term,
possibly due to continued mandibular remodeling.
•Herbst continued to produce more vertical change and incisor
proclination, making it more suited for deep bite correction but with
more dental side effects.

29/07/2025 56
Herbst: Stronger short-term skeletal and dental effects; better for severe Class II and deep bites.
MA: More controlled, ideal for mild–moderate Class II; better aesthetics and less proclination.

29/07/2025 57
LIMITATIONS OF THE STUDY (HOSSEINI ET AL., AJODO, FEB 2024)
No Control Group (Growth Effect Not Isolated)
Retrospective Study Design
No Transverse Evaluation
No Assessment of MA Patient Compliance
Number of appointments, emergencies, or appliance breakages
were not recorded — important for understanding real-world
treatment efficiency.

29/07/2025 58
Small Sample Size
Cephalometric 2D Limitations
No Evaluation of Soft Tissue Changes
No Assessment of Root Resorption or Tooth Movement Side Effects

29/07/2025 59
RELATED ARTICLES

29/07/2025 60
Objective: The objective of this study was to evaluate and compare the
effects of PowerScope and Forsus in the treatment of Class II division 1
malocclusion.
This double-blind, randomized controlled trial compared the skeletal and
dentoalveolar effects of PowerScope and Forsus appliances in 28 Class II Div
1 patients. Participants were randomly allocated into two groups (n=14 each).
After dropouts, data from 26 patients were analyzed. Secondary outcomes
included patient comfort and operator convenience, with blinding and
statistical analysis ensuring unbiased results.
(Angle Orthod. 2018;88:259–266.)

29/07/2025 61
Results: A significantly greater mesial mandibular movement and improvement in sagittal
skeletal relation were found in the Forsus patients (P .05). The forward movement of the
mandibular molar and incisors were greater in the PowerScope patients (2.3 mm and 2.80 mm)
than in the Forsus patients (1.9 mm and 2.38 mm).
Conclusions: Both PowerScope and Forsus are effective in correcting Class II malocclusion. The
percentage of dentoalveolar effects in correcting Class II malocclusion is more for PowerScope
when compared with Forsus. Patient comfort was the same with both appliances. This trial was
registered.

29/07/2025 62
The objective of this research was to compare the 2 treatment protocols including a functional
mandibular advancer (FMA; Forestadent, Pforzheim, Germany) followed by multibracket appliances
(MBAs) vs a Forsus device (3M Unitek, Monrovia, Calif) in combination with MBA concerning
treatment outcomes and posttreatment stability
This study was conducted using lateral cephalograms of patients who were treated with MBA, which
was used either after an FMA or concurrently with a Forsus device, and of patients who had untreated
Class II malocclusion (control group). Each group consisted of 19 subjects in cervical stage 2 or
cervical stage 3 stages according to the cervical vertebral maturation index. Cephalograms were taken
for the treated groups at T1 (pretreatment), T2 (completion of the MBA treatment), and T3 (at least
2 years after T2).

29/07/2025 63
Conclusions
Treatment protocol including an FMA was found to be more effective with mandibular skeletal
effects and was more stable with a lesser degree of relapse in overjet and overbite than the Forsus
protocol.

29/07/2025 64
Objective
To evaluate the coefficient of efficiency and effectiveness of removable and fixed functional
appliances in class II malocclusion treatment.
Data sources
Search of studies in five databases (Medline via PubMed, Cochrane library, LILACS, SCOPUS,
and SciELO) that measured mandibular skeletal changes following functional therapy was
conducted until 15 April 2024.

29/07/2025 65
Results
From 6796 potentially eligible studies, 90 were considered for this systematic review. Four were
RCTs which were graded with the Cochrane risk of bias tool. Three were assessed as having low
and one as having moderate risk of bias. The other 86 studies were graded with the modified
Downs and Black tool which revealed that 47 showed low, 38 low/moderate, and 1 a moderate
risk of bias. The most commonly assessed appliances were the Twin Block which was used on
783 patients, the Frankel appliance on 573, the Herbst appliance on 530, the Activator on 449,
the Forsus appliance on 394, the MARA appliance on 202, and the Bionator on 133, for a total of
3064 treated patients.

29/07/2025 66
This systematic review provides conclusive evidence that the Twin Block appliance demonstrated
the highest coefficient of efficiency among all the evaluated appliances (0.46 mm/month), while
the Forsus fatigue resistant device (FFRD) had the highest coefficient of efficiency among the
fixed functional appliances (0.41mm/month)

29/07/2025 67
CONCLUSION
Both Herbst and MA appliances effectively reduced overjet, overbite, and corrected the
Class II molar relationship in growing patients via skeletal and dental changes.
Treatment duration was similar for both groups. The Herbst appliance showed ,Greater
correction in overjet, Wits, molar relationship, and overbite. This was mainly due to
overcorrection and longer appliance phase. However, it caused more mandibular incisor
proclination due to lack of control.

29/07/2025 68
The MA (Mandibular Advancement with aligners) showed, Better control over mandibular incisor
inclination. Superior vertical control, especially in preventing molar extrusion. This makes it more
suitable for dolichofacial (long-face) Class II patients.

A COMPARISON OF SKELETAL AND DENTAL CHANGES IN PATIENTS WITH A CLASS II RELATIONSHIP TREATED WITH CLEAR ALIGNER MANDIBULAR ADVANCEMENT AND HERBST APPLIANCE FOLLOWED BY COMPREHENSIVE ORTHODONTIC TREATMENT-AJODO 2024

More Related Content

Similar to A COMPARISON OF SKELETAL AND DENTAL CHANGES IN PATIENTS WITH A CLASS II RELATIONSHIP TREATED WITH CLEAR ALIGNER MANDIBULAR ADVANCEMENT AND HERBST APPLIANCE FOLLOWED BY COMPREHENSIVE ORTHODONTIC TREATMENT-AJODO 2024

More from Dr Anurag JB

Recently uploaded

A COMPARISON OF SKELETAL AND DENTAL CHANGES IN PATIENTS WITH A CLASS II RELATIONSHIP TREATED WITH CLEAR ALIGNER MANDIBULAR ADVANCEMENT AND HERBST APPLIANCE FOLLOWED BY COMPREHENSIVE ORTHODONTIC TREATMENT-AJODO 2024