Relapse and Retention
Definition:
Retention, which is the last phase of
orthodontic treatment, is a most
important one, where teeth are
held in an esthetic and functional
position.
Definition:
Relapse is the change in tooth
position toward the former location
following active orthodontic
treatment.
First part: Review
• 1.Occlusion
Kinsley
• Occlusal relationship is the most
essential factor on the stable position
of the posterior teeth after treatment.
Review
• 2. Root apicalis bascal bone
• Axel Lundstrom ：Root apicalis bascal bone
•
is one of the most important factors to
correct the malocclusion and maintain the
normal occlusal relationship.
Mc cauley proposed that if the intercuspid
width and the molar width can maitain ,the
mini retention is needed.
Review
• 3.The mandibular incisor
•
Grieve and Tweed: the mandibular
•
incisors should be positioned on the bascal
bone of mandibular vertically.
Rogers introduced that it’s necesseary
to establish the functional balance
between the muscles.
Second Part:
The principle of Retention Stability
• 1.The tendency that the teeth move
to the oringinal position muscles,
root apicalis bascal bone, fibers and
the bone morphology.
2. Remove the pathogeny of malocclusion
could prevent relapse Tongue gesture is
the most covert oral habits that affect the
retention.
• 3.Over correction is a protective issue.
• 4.Good occlusal relationship is advantage
•
•
for the stability of the teeth.
5.To rebuild the bone and the tissue
surrounding takes time.
6.The mandibular incisor placed vertically
is propitious to retention.
• 7.The treatment in the develop
phases reduces the possibility of
retention.
• 8.The farer teeth moved,the lower
pollibility of retention there is.
• 9.The configuration of mandibular is
hard to be remained permanencely.
Third part:
Factors affecting stability
• 1.The maladjustment of the tooth size
• 2.Inclination
• 3.The horizontally maladhustment
• 4.The third molars
• 5.The growth development and gender
difference.
Third part:
Factors affecting stability
• 6.Relapse
(1)Alveolar bone
(2)Treatment speed
(3)Retetion time
Third part:
Factors affecting stability
• (4)Muscle system
• On retention,besides to control the
tongue
gusture
and
abnormal
swallow hapits, there’s no standard
research discussing the relationship
between the normal muscle activity
and the stability of teeth position.
Third part:
Factors affecting stability
(5)Occlusal balance
Adjust the specific teeth is
advantage to the function system.
Third part:
Factors affecting stability
• 7. Special consideration on mandibular
•
•
•
tooth arche
(1)．Intercuspid width
The width between mandibular canines
are apt to return to the origin before the
treatment in all the cases.
So the original width could be regarded as
a standard to guide the diagnosis and
treatment.
Third part:
Factors affecting stability
• (2)．The stability of mandibular
anterior teeth
• (3)．Extraction of incisors
1.Natural retention
(1)Post treatment of crossbite
①The overbite is deep enough after
the correction of crossbite
②The appropriate inclination can be
maintained
in
posterior
teeth.Sometimes the over correction
should be involved.
(2)Usually retention is not necesseary if
there’s no following treatment in serial
extraction.
①Extraction of gingival erupted canine
②The cases in which extraction of a
canine or more teeth is necesseary.
(3) The cases in which the maxillary
development has stopped,retention
is not necesseary
(4)Low positioned or embedded tooth
that involved in the dental arche by
enlarging it.
• 2.Limited retention
• Many cases are this type. Most of
them needs adjustment of muscle
and peridontal tissue.Some of them
have to keep retention until the
period of growth is over.
（1） Vertical Rretention is needed
in the deep overbite cases.
①Anterior teeth guide plate could
be applied when the correction
was obtained by anterior intrusion.
• ②The correction of overbite with
fixed appliences is accompanied
with the extusion,so the retention
must be kept until the vertical height
was caught up.
③The correction obtainted by inclining
the occlusal plate should be involed
in retention for longer period.
• (2)Correctino of the rotated tooth in
early period
• ①Retention should be applied until
the tooth root forms completely.
• ②Correction
of
the
rotated
mandibular incisors. In these cases
the labial arch should be applied .
• ③After
the
rotation
of
the
canine,pre-molar
and
the
molar,transverse
fiber
operation
should be applied to enhance
stability.
• 3.Permanent and hemi-permanent
retention
• (1)The correction of mandibular
arche needs permanent and hemiperamanent retention to maintain
the occlusal attachment of posterior
teeth.
• (2)Permanent retention is necesseary for
the cases with spaces in anterior teeth
originally.
(3)Permanent retention should be applied
when there’r badly rotated or ligulaly
dislocated teeth in adult cases.
(4)The space between the upper incisors
has been closed when other teeth are
nomally placed.
Hawley’s retainer
Hawley ‘s retainer
positioner
Fixed labial and lingual arch retainer
Special retention of different
type of malocclusion
• First Skeletal Ⅱ
Relapse
• 1. Upper arche moves forwardly,lower
arche moves backwardly at the same time
• 2.Growth causes
• 3. overcorrection
• Control
• 1.Removable+Headgear
• 2.Activator retaining appliance
• 1-2years in worse cases
• Second Skeletal Ⅲ
Relapse Growth of mandibular
Control mildly activator retainer
Positioner
Worse Operation
•
•
•
•
•
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Third Retention of deep overbite cases
Biteplate Avoid deep overbite
Fourth、Retention of openbite
1.Control the eruption of upper molars
2.Removable retainer+ high pull
Headgear
Bite block with posterior teeth
Retaining period
•
The retention period depend on
the type of the retainer above ，
combining with diagnosis ,treatment
design,the original malocclusion,and
the growth situation .
•
According to the standard
period of half a year , retainer is
worn fulltime in the first 3
months,and step down the time.
This standard is more appropriate
for most of the patients who are
treated with removable appliance.
•
More people would agree to spend
another 1 year or more on retention after
the treatment through fixed appliances
and some people believe it should be worn
as long as the appliances. Usually full time
a day is necesseary during the first 3
mounths，and only night in the following
half year,and in the last 3 years tertianly
to 1-2days a week .One year or a half is
necesseary if fixed appliances are applied.
Othodontics
• Fundaments Etiology Growing
•
•
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•
development Biologic mechanism
Diagnosis Taxology Cephalometrics
Treatment design
Treatment Orthodontic appliances and
techniques
Treatment for different type of
malocclusion
Relapse and retention