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the second stage of comprehensive treatment: correction of molar relationship (with additions)
Transcript of the second stage of comprehensive treatment: correction of molar relationship (with additions)
correction by distal movement of upper molars
2 reasons for extracting teeth:
1) To provide space to align crowded incisors without creating excessive protrusion
2) To allow camouflage of moderate Class II or Class III jaw relationships
closure of extraction spaces
18-Slot Edgewise: Closing Loops
correction of molar relationship
1) Differential growth of the jaws
2) Differential anteroposterior movement of the upper and lower teeth
camouflage by Tooth Movement
Treatment with tooth movement is successful only if both the facial appearance and dental occlusion are satisfactory.
the second stage of comprehensive treatment: correction of molar relationship and space closure
Extraoral forces for Growing patients with class II
The location of the neck/ head strap will determine the direction of the line of force, resulting in extrusive or intrusive pulls.
High pull headgear
Places a distal and upward (intrusive) force on the molars and the maxillary complex.
Low pull headgear
Places a distal and downward (extrusive) force on the molars and maxillary complex.
Combination or straight pull headgear
May have different force directions according to the relative contribution of each component in the vertical direction.
If both components were to deliver equal and opposite forces, the resultant effect would be slightly upward and distal.
extraoral forces for growing patients with class III
Made up of a soft pad that rests against the chin, and is connected on top of the head with an adjustable strap.
Designed to work together with a palatal expansion appliance to help correct open bites and slow down excessive downward growth of the mandible.
Between the ages of 6 and 11
Functional appliance for growing patients with class II
FR2 (functional regulator 2)
2 separate appliances (maxillary and mandibular) working together to maintain an advanced mandibular position.
This is achieved by incorporating acrylic blocks into the occlusal surface of the appliances which interface with each other in the bicuspid region at a 70 degree angle.
Bionator I (to Open)
used to treat patients with a Class II malocclusion and a deep bite
there are fluted channels angled facially into the acrylic that guide the eruption of posterior teeth
An acrylic cap over the mandibular incisors and the maxillary incisors prevents the undesirable eruption of the anterior teeth while also controlling flaring of the mandibular incisors
omega loop coffin spring joins the two halves across the palate for rigidity and can be activated for lateral expansion of the appliance
Bionator II (to Close)
used to treat patients with a Class II malocclusion with an anterior open bite.
Full acrylic coverage of the posterior teeth is used to prevent undesirable eruption in this area and to hold the protrusive position of the mandible.
The anterior teeth are left uncovered allowing them to erupt.
Functional appliance for growing patients with class iii
Reverse pull headgear or face mask
bring the upper jaw and teeth forward while restraining forward growth of the
Used when an openbite is present or when the
upper jaw is under-developed.
Functional Regulator III
A fixed appliance for the distalization and derotation of the upper first molars
A large Nance type acrylic button is used in conjunction with wire rests that are bonded to the occlusal surface of the bicuspids to provide anchorage.
Helical springs of .032 TMA wire
A variation of the pendulum appliance wherein an expansion screw is added to the acrylic portion for lateral development.
A Pendex design with additional wires extended out of the acrylic plate and soldered to the molar bands.
These wires prevent the pre-activated springs from distalizing the molars until after the arch has been widened.
MDA (Maxillary Distilizing Appliance)
A T-Rex variation with additional wires extended out of welded sheathes on the screw underside.
A fixed appliance that uses a combination of NiTi springs and set screws and designed for either unilateral or bilateral molar distalization.
orthodontic Camouflage: Jaw discrepancy is no longer apparent.
The following three patterns of tooth movement can be used to correct a Class II malocclusion:
1) A combination of retraction of the upper teeth and forward movement of the lower teeth, without tooth extractions
2) Retraction of maxillary incisors into a premolar extraction space
3) Distal movement of maxillary molars and eventually the entire upper dental arch.
camouflage by tooth movement
Minimum Incisor Retraction
18-slot edgewise: closing loops
The major possibilities for producing clinically satisfactory loops are reducing wire size or incorporating additional wire by changing length, interbracket distance, and/or loop configuration.
additional design principles
Important principle: "fail safe"
Tooth movement should stop after a prescribed range of movement even if the patient does not return for a scheduled adjustment
additional design principles
Deliver a continuous, controlled force designed to produce tooth movement at a rate of approx. 1 mm per month
Design should be as simple as possible
Activation when opening or closing
Specific recommendations for closing loop archwires with the 18-slot appliance and narrow brackets are:
16 × 22 wire
, delta or T-shaped loops,
7 mm vertical height
, and additional wire incorporated into the horizontal part of the loop to make it equivalent to
10 mm of vertical height.
Gable bends of 40 to 45 degrees
total (half on each side of the loop).
Loop placement 4 to 5 mm distal
to the center of the canine tooth, at the center of the space between the canine and second premolar with the extraction site closed.
maximum incisor retraction with 18-slot appliance
stabilizing lingual arches
and proceed with en masse space closure.
2) Reinforce maxillary posterior anchorage with
and (if needed) use
Class III elastics
from high-pull headgear to supplement retraction force in the lower arch, while continuing the basic en masse closure approach.
3) Retract the canines independently, preferably using a
segmental closing loop
, and then retract the incisors with a second closing loop archwire.
to stabilize the posterior segments.
christine joy s. chny, dmd