The document discusses factors related to stability and retention in class II division 1 malocclusions. It covers 3 main topics: 1) The relationship between stability and extraction patterns, finding that nonextraction and premolar extraction have similar long-term stability. 2) The relationship between treatment mechanics and stability, finding stability with functional appliances, Herbst, Twin Force Bite Corrector. 3) Surgical vs conventional treatment, finding functional appliances and surgery have similar stable results, though surgery has more vertical relapse. Relapse is multifactorial and can be reduced by ensuring proper occlusion, avoiding overcorrection of lower incisors, and continued retention as needed.

1. Stability and retention in class II
division I malocclusion
Evidence related to stability of class II D1 malocclusion
 Relationship between stability and pattern of extraction
 Relationship between different treatment mechanics and stability
 Surgical versus conventional treatment
1. Relationshipbetweenstability and pattern of extraction
Post-treatmentstability in Class II nonextractionand maxillary premolar
extraction protocols, Guilherme. 2012
Aim: To cephalometrically compare the overjet, overbite, and molar and canine
relationship stability of Class II malocclusion treatment with and without
maxillary premolar extractions.
Method: Two groups of 30 patients each with pre- and posttreatment matching
characteristics and satisfactory finishing were used. Group 1 consisted of 30
patients treated with nonextraction at a mean pretreatment age of 12.14 years,
while group 2 consisted of 30 patients treated with maxillary first premolar
extractions at a mean pretreatment age of 12.87 years. Lateral cephalograms
obtained before and after treatment and at a mean of 8.2 years after the end of
treatment were compared.
Results: longterm stability of the overjet, overbite, and molar and canine
relationships were similar in the groups. There were significant but weak
correlations between treatment changes in overjet, overbite, and canine
relationships with their long-term posttreatment changes.

2. Conclusion: Nonextraction and maxillary premolar extraction treatment of
complete Class II malocclusion have similar long-term posttreatment stability in
terms of overjet, overbite, and canine and molar relationships
Long-term stability of Class II malocclusion treated with 2- and 4-premolar
extraction protocols , Janson , 2009
objective of this study was to cephalometrically compare the stability of
complete Class II malocclusion treatment with 2 or 4 premolar extractions after
a mean period of 9.35 years.
A sample of 57 records from patients with complete Class II malocclusion was
selected and divided into 2 groups. Group 1 consisted of 30 patients with an
initial mean age of 12.87 years treated with extraction of 2 maxillary premolars.
Group 2 consisted of 27 patients with an initial mean age of 13.72 years treated
with extraction of 4 premolars.
group 1 had a statistically greater OJ relapse than group 2. On the other hand,
group 2 had a statistically greater molar-relationship relapse toward Class II.
There were significant positive correlations between the amounts of treatment
and posttreatment dentoalveolar-relationship changes.
Conclusions of complete Class II malocclusions with 2 maxillary premolar
extractions or 4 premolar extractions had similar long-term posttreatment
stability.
2. Relationshipbetweendifferent treatment mechanics and stability
Long-term stability of Class II, Division 1, nonextractioncervicalface-bow
therapy: II. Cephalometric analysis. Elms 1996
The long-term stability of Class II, Division 1 nonextraction therapy, using
cervical face-bows with full fixed orthodontic appliances was evaluated for 42

3. randomly selected patients. Each patient was treated by the same practitioner,
with the same techniques, and the treatment goals had been attained for all
patients. Pretreatment records were taken at a mean age of 11.5 years; the
posttreatment and postretention records were taken 3.0 and 11.6 years later,
respectively. The ratio of treatment proclination of incisors to posttreatment
retroclination is approximately 5:1. Similarly, for every 3 degrees of molar tip
back, there was approximately 1 degree of relapse. It is concluded that
nonextraction therapy for Class II malocclusion can be largely stable when the
orthodontist ensures properpatient selection and compliance and attains
treatment objectives.
Long-Term Stability of Class II Correctionwith the Twin Force Bite
CorrectorChebber 2010
Follow-up studies of Class II patients have shown insignificant tendency to
return to the original malocclusion after treatment with small increases in
overjet and overbite and partial relapse of the molar relationships. Proper
interdigitation of the posterior occlusion after bracket removal appears to be an
important contributor to the stability of the correction.
Occlusalstability of adult Class II Division 1 treatment with the Herbst
appliance, Bock
During recent years, some articles have been published on Herbst appliance
treatment in adult patients, an approachthat has been shown to be most
effective in Class II treatment in both early and late adulthood. However, no
results on stability have yet been published. Our objective was to analyze the

4. short-term occlusal stability of Herbst therapy in adults with Class II Division 1
malocclusions.
Methods:The subjects comprised 26 adults with Class II Division 1
malocclusions exhibiting a Class II molar relationship$0.5 cusp bilaterally or
$1.0 cusp unilaterally and an overjet of $4.0 mm. The average treatment time
was 8.8months (Herbst phase) plus 14.7 months (subsequent multi-bracket
phase). Study casts from before and after treatment and after an average
retention period of 32 months were analyzed.
Results: After retention, molar relationships were stable in 77.6% and canine
relationships in 71.2% of the teeth. True relapses were found in
8.2% (molar relationships) and 1.9% (canine relationships) of the teeth. Overjet
was stable in 92.3% and overbite in 96.0% of the patients; true relapse did not
occur.
Conclusions: Herbst treatment showed good occlusalstability 2.5 years after
treatment in adults with Class II Division 1 malocclusions.
Stability of Class II, Division 1 Treatment with the Headgear-Activator
Combination Followedby the EdgewiseAppliance Janson, 2004
This study assessed the stability of the headgear-activator combination
treatment, followed by edgewise mechanotherapy, 5.75 years after treatment.
The experimental group consisted of 23 patients who were evaluated during
treatment and after treatment. Two compatible control groups consisting of 15
Class II, division 1 patients and 24 normal occlusion individuals were used.
This enabled us to evaluate the changes during treatment and after treatment,
respectively. Results showed that the anteroposterior dentoalveolar changes and
the maxillary and the mandibular positions remained stable in the long term.

5. However, there was a slight relapse of the maxillomandibular relationship
probably because the maxilla resumed its normal development and the
mandibular growth rate was smaller than in the controlgroup.
The overbite demonstrated a statistically significant relapse that was directly
proportional to the amount of its correction. Initial Class II malocclusion
severity (ANB and Wits), and initial molar relationship did not present any
correlation with molar relationship and overjet relapse. However, the initial
overjet presented a low but statistically significant correlation with molar
relationship relapse and overjet relapse.
3. Surgicalversus conventionaltreatment
Long-term comparisonof treatment outcome and stability of Class II
patients treated with functional appliances versus bilateral sagittalsplit
ramus osteotomy.Berger2005
The objective of this study was to compare the treatment outcomes and stability
of patients with Class II malocclusion treated with either functional appliances
or surgical mandibular advancement.
The early-treatment group consisted of 30 patients (15 girls, 15 boys), with a
mean age of 10 years 4 months (range, 7 years 5 months to 12 years 5 months),
who received either Fränkel II (15 patients) or Herbst appliances (15 patients).
The surgical group consisted of 30 patients (23 female, 7 male), with a mean
age of 27 years 2 months (range, 13 years 0 months to 53 years 10 months).
They were treated with bilateral sagittal split ramus osteotomies with rigid
fixation. Lateral cephalograms were taken for the early-treatment group at T1
(initial records), T2 (completion of functional appliance treatment), and Tf
(completion of comprehensive treatment). In the surgical group, lateral
cephalograms were taken at T1 (initial records), T2 (presurgery), T3

6. (postsurgery), and Tf (completion of comprehensive treatment). The average
times from the completion of functional appliance treatment or surgery to the
final cephalograms were 35.8 months and 34.9 months, respectively.
In the functional appliance group, the mandible continued to grow in a
favorable direction even after discontinuation of the functional appliance. Both
groups had stable results over time. Both groups finished treatment with the
same cephalometric measurements. Significant skeletal and softtissue changes
were noted in the treatment groups due to either functional or surgical
advancement of the mandible. More vertical relapse was noted in the surgical
group than in the functional group.
This study suggests that early correction of Class II dentoskeletal malocclusions
with functional appliances yields favorable results without the possible
deleterious effects of surgery.
Long-term follow-up of ClassIIadults treatedwith orthodontic
camouflage:a comparisonwith orthognathic surgeryoutcomes Mihalik
2003
Looking at long-term stability of adult Class II treatment it was found that
overbite was equally stable in both groups, but overjet relapsed twice as often in
surgery patients.
Stability of skeletalClass II correctionwith 2 surgicaltechniques: The
sagittalsplit ramus osteotomyand the total mandibular subapical alveolar
osteotomy, Valmy 2001
Combined orthodontic and surgical treatment of severe Class II dentoskeletal
deformities with the use of the bilateral sagittal split ramus osteotomyis a

7. routine procedurein orthodontic practices. However, an alternative surgical
technique, the total mandibular subapical alveolar osteotomy, could be used for
the same purpose. The aim of this investigation was to compare the stability of
the sagittal split ramus osteotomy with the total mandibular subapical alveolar
osteotomyin the correction of dentoskeletal Class II malocclusions. Forty
patients that exhibited Class II dentoskeletal relationships were included in the
study. Twenty of these patients had mandibular advancement with the sagittal
split ramus osteotomy; the remaining 20 patients had advancement of the whole
lower alveolar segment with the total mandibular subapical alveolar osteotomy.
The cephalograms studied were taken before the surgical procedure (T1 = 4
weeks before operation), immediately after the procedure(T2 = 10 days after
surgery), and 1 year later (T3). The results of this study show that both
procedures are equally stable when correcting Class II malocclusions. This was
proved by the stability of the correction of overjet, B point, and incisor-
mandibular plane angle. There were no statistically significant differences
between or within the groups in the position of these landmarks over time.
There was a statistically significant change in the position of pogonion from T1
to T2 (P < .0028) between the groups, although at T3 this difference was not
significant (P < .05). There were no significant changes in face height either
within or between the groups over time. The hard/soft tissue interactions for the
total mandibular subapical alveolar osteotomywere as follows: The lower lip
advanced 60% to the incisor movement; soft tissue B′ point responded with a
130% advancement in relation to the change in its hard tissue counterpart. Soft
tissue pogonion advanced 90% in relation to the hard tissue landmark. The data
suggest that the total mandibular alveolar osteotomy is the treatment of choice
for the correction of severe dentoalveolar retrusive Class II malocclusion for
which alteration of the mentolabial sulcus is desirable.

8. Cause of relapse aftertreatment of class II D1 malocclusion
1. Local factors causing relapse (forward in the upper arch, backward in the lower
arch, or both) due to PD changes or dental relapse.
2. Differential growth of the maxilla relative to the mandible. Future mandibular
growth is also important for the stability of overjet correction. A significant
backwards (clockwise) mandibular growth rotation can lead to an increase in
overjet as the lower incisors are also rotated downwards and backwards. The
resultant increase in vertical facial dimension with this type of growth rotation
also reduces lip competency, which predisposes to relapse.
3. Continued habits
4. Soft tissue factors
5. Iatrogenic or Delayed treatment failure specially in surgical treatment.
6. Idiopathic causes eg: ICR
7. Combination
Factors that be consideredto control relapse potential
1. Regarding AP changes in the lower incisors: In Class II treatment, it is
important not to move the lower incisors too far forward, if happen should be
permanently retained.
2. Regarding the AP changes in upper incisors: Ensuring that the upper incisors
are retracted sufficiently to be in controlof the lower lip.
3. Regarding the occlusion: Proper interdigitation of the posterior occlusion after
bracket removal appears to be an important contributor to the stability of the
correction. Significant amounts of relapse were observed by Pancherz9 and
Wieslander2002 in cases treated to unstable occlusalrelationships.

9. 4. Regarding anteroposterior change: Overcorrection of the occlusal relationships
as a finishing procedure is an important step in controlling tooth movement that
would lead to Class II relapse. Even with good retention, 1 to 2 mm of
anteroposterior change caused by adjustments in tooth position is likely to occur
after treatment, particularly if Class II elastics were employed. This change
occurs relatively quickly after active treatment stops.
5. Regarding growing patient: who has a class II skeletal at the start and treated by
on camouflaging or comprehensive functional-fixed appliance treatment, further
growth (which depend on age and geneder) almost surely will result in some
loss of the correction as the original growth pattern persists. This relapse
tendency can be controlled in one of two ways.
• Continue headgear to the upper molars on a reduced basis (at night, for
instance) in conjunction with a retainer to hold the teeth in alignment.
• Functional appliance of the activator-bionator type to hold both tooth position
and the occlusal relationship. The construction bite for the functional appliance
is taken without any mandibular advancement—the idea is to prevent a Class II
malocclusion from recurring, not to actively treat one that already exists. The
functional appliance will be worn only part time, typically just at night, and
daytime retainers of conventional design also will be needed to control tooth
position during the first few months.
6. Regarding the treated deep overbite:
A. Good interincisal angle. The interincisal angle must be corrected (average 135°)
in addition to the overbite being reduced in order to prevent re-eruption of the
incisors after treatment.
B. Correct mandibular incisor edge-centroid relationship.

10.  Possibly the most important factor in overbite stability in all treated cases is
correction of the relationship between the mandibular incisor edge and the
maxillary incisor rootcentroid
 This is measured as the distance between the perpendicular projections of these
two points on the maxillary plane (0–2 mm).
 This may be achieved by either retraction of the maxillary incisor root centroid
using fixed appliances with palatal root torque, or proclination of the
mandibular incisors to advance their edges.
 The decision depends on a number of factors including the facial profile, PD
supportand growth potential.
 If a patient has a retrognathic mandible, it is possible to procline the maxillary
incisors and to either surgically advance the mandible or in a growing patient to
use a functional appliance to help advance the mandibular incisors.
 In a patient with good facial profile aesthetics, the treatment may be carried out
with fixed appliances alone, so long as the palatal alveolar process is thick
enough to allow retraction of the maxillary incisor rootcentroid. The crowns of
the incisor teeth should also be maintained within the zone of soft tissue
equilibrium between the musculature of the tongue and the lips. An interesting
proposition is that in Class II division 2 malocclusions it may be possibleto
intrude and torque the maxillary incisor roots palatally, allowing the mandibular
incisor crowns to be proclined and hence occupythe position previously
occupied by the maxillary incisor crowns, thus maintaining the incisor complex
within the zone of soft tissue equilibrium.
C. Proclination of the lower labial segment in Class II cases. This may still be
unstable in the long term due to pressure from the lower lip.(Mills 1979)

11. Therefore, long-term retention may be required in suchcases and must be
discussed with the patient prior to treatment.
D. Avoid change in intermaxillary height in non-growing patients. The extrusion of
molars in non-growing patients is unstable, as the muscular forces from the
pterygo-masseteric sling will re-intrude the molars if the posterior vertical face
height has not accommodated their extrusion.
E. Vertical facial growth. it continues well into the late teenage years. As the
pattern of facial growth does not tend to change following treatment it is
prudent to place a bite-plane on the maxillary removable retainer after the
completion of orthodontic treatment. This may be worn on a part-time basis in
order to maintain the corrected overbite until vertical facial growth has
subsided. using active removable upper retainer made so that the lower incisors
will encounter the baseplate of the retainer if they begin to slip vertically behind
the upper incisors. The procedure, in other words, is to build a potential
biteplate into the retainer, which the lower incisors will contact if the bite begins
to deepen. The retainer does not separate the posterior teeth. Because vertical
growth continues into the late teens, a maxillary removable retainer with a bite
plane often is needed for several years after fixed appliance orthodontics is
completed
7. Regarding the treated anterior open bite:
• Continue stopping the habit with tongue spur which is questionable for its
effectiveness
• a maxillary retainer with bite blocks (or a functional appliance) to impede
eruption
• high-pull headgear.

12. Common Questions related to this topic
Are There Any Circumstances in Which LowerIncisor ProclinationIs
Likely to Be Stable?
1. Pre-existing lip trap
2. Digit habit
3. Incisors held artificially upright by the occlusion (such as a class II division 2)
(Mills, 1973)
4. following orthognathic surgery in class III malocclusion (Artun et al., 1990)
Is Lower IncisorProclination Likely to Exacerbate GingivalRecession?
Uncontrolled incisor proclination is inadvisable and risks further recession.
However, the association between proclination and recession is weak and

13. unpredictable. A retrospective study of 300 adult patients undergoing
orthodontic treatment demonstrated an average increase in lower incisor
recession of just 0.14 mm with incisor proclination (Allais and Melsen, 2003).