functional appliances. introduction originated and developed in europe controversy a group of...
TRANSCRIPT
FUNCTIONAL APPLIANCES
INTRODUCTION
• Originated and developed in Europe
• Controversy
• A group of orthodontic appliances
features
• Harness forces of muscles
• Construction bite
• Only work in growing children
• Can’t correct the teeth irregularity
Correction of Class malocclusionⅡCorrection of Class malocclusionⅡ
Categories of functional appliances
• Passive tooth-borne appliances: no active components
• Active tooth-borne appliances:including expansive screw or springs to move teeth
• Tissue-borne appliances: Functional Regulator-FR
Effects of functional appliances
Dento-alveolar changes
• Antero-posterior: Anterior movement of lower teeth, posterior movement of upper teeth.
• Vertical: lower posterior teeth erupt.
Modification of Maxillary growth
• Restrain the forward growth of maxilla
• Catch up growth occurs after treatment
Cephlomatric superimposition
Changes in mandibular growth
• Stimulate mandible growth
• Improve the growth direction of mandible
Cephlogram superimposition
Changes in glenoid fossae
• Remolding of the glenoid fossa more anteriorly
Indications for functional appliances
• The patient must still be growing,preferably approaching a phase of rapid growth.
• The pattern and direction of facial growth should be favorable.
• The profile improved immediately as the patient move mandible forward.
• The patient must be well motivated.• Dentition are well aligned
The timing of treatment
Late stage of mixed dentition,1-2 years before the pubertal growth occur
Female: 9~10 year old
Male: 11~12 year old
Management of functional appliances
Management of functional appliances
Diagnosis
• Skeletal or non-skeletal(dental)
• Mandibular retrusion or maxillary protrusion
• Degree of severity
Appliance Design
• No ideal appliance can be used in all situations
• Exactly what is desired in the treatment
• consideration of cost, complexity, acceptability
• Vertical control
• Mobile or exfoliating primary teeth
impression
• Differ with the diagnostic records
• Areas where appliance components will contact soft tissues must clearly delineated
• The impression must not stretch soft tissues in areas of contact with the appliance.
Bite registration
1.Anteroposterior dimension: for most patients: 4~6mm (edge to edge if no uncomfortable)
2.Vertical opening: 3~4mm in incisor region
Bite registration --methods
• A horseshoe-shaped wax bite rim is prepared
• Guiding the mandible into planned position
• Forming the wax bite
• Check and hardened
fabrication
Fit the appliance
• Instruction
• Check the surface of roughness, adjust clasps, capping
• How to insert and remove the appliances
• Initially few hours, gradually increase the wearing time. At least 14 hours each day over 2 weeks
First review appointment2 weeks later
Check and trim the appliance
Review appointment
• 1.Every 6~8 weeks
• 2.Check the appliance
• 3.Assess progress(improvement or no/slow improvement)
4.Adjustment
• Trimming of interocclusal elements to allow teeth erupt where desired
• Adjustment of the labial bow: reduce its contact with the anterior teeth
• Outward bending of buccal shields and lip pads,facilitate arch expansion
Retention
• Gradually reduce the amount of wearing time till sleeping hours only
• Period: the pubertal growth is over
Popular types of appliances
Activator
Tu
construction
• Base plane• Lip bow:transmit forces
to upper incisors• Lower incisors
capping: minimize ⑴the tendency of lower incisors procline
reducing overbite⑵
principles
Muscles stretched-producing forces-retracting mandible-transmitted to maxilla through labial bow-restraining the maxillary growth
Rules for construction bite
• In a forward positioning of the mandible of 7-8mm,the vertical opening must be slightly to moderated(2-4mm)
• If the forward positioning is no more than 3-5mm,the vertical opening should be 4-6mm
• The Activator can correct lower midline shift or deviation
Management
Checkup appointments should be scheduled every 6 weeks:
1.observing shiny surface to determine whether the appliance be worn correctly
2.trimming and reshaping acrylic guild areas
3.Acrylic contact guild plane often must be resealed.
4.The labial bows must be checked
5.In expansion treatment the jackscrew are normally activated by the patients at 1-week interval. Check the screw
Trimming
1.vertical control
• For dolichofacial patients:intrude molars, extrude incisors
• For branchfacial patients: intrude incisors, extrude molars
Acrylic contact Intrusion of the molars
Acrylic contour for extrusion of the molars
Intrusion of the incisors
2.sagittal control
Retrusion of the incisors
Mesial movement of molars
Distal movement of molars
3.transverse movement
bionator
principles
• Less buckly
• Adjust the function of tongue
• The working bite can’t be opened and must be positioned in an edge-to-edge relationship. If the overjet is too large,can be done step by step.
Types of Bionator
• Standard Bionator• Horseshoe-shaped
acrylic lingual plate• Palatal bar• Labial bow extend
buccally• No incisors capping
Open-bite Bionator
Class BionatorⅢ
Indications
• The dental are well aligned originally
• The mandible is in a posterior position
• The skeletal problem is not too severe
• A labial tipping of the upper incisors is evident
Clinical management
• The time interval between office visit is 3-5 weeks
• Adjust labial bow to touch the teeth lightly
• Trimming the interocclusal block to guild premolar into full occlusion
Frankel appliance(FunctionalRegulator-FR)
• The large part of Frankel appliance is confined to the oral vestibule
• The buccal shields and lip pads hold the buccal and labial soft tissue away from the teeth,eliminating restrictive influence
• The manner in which the anteroposterior correction is different
tu
variation
• FR1:correction of class division 1Ⅱ• FR2:correction of class division 1 and 2Ⅱ• FR3:correction of class Ⅲ• FR4:correction of openbite
• Among them, the FR2 and FR3 are often used
FR3
• Acrylic parts:• Lip pads:eliminate
restriction,stimulation of bone growth; transmitting forces to mandible
• Buccal shields: maxillary expansion
Steel wire
• Lower labial bow:restrain mandible
• Protrusion bow:stimulate forward movement of maxillary incisors
• Palatal bar: stabling component
• Occlusal rests:prevent lower molar erupt,open cross-overbite
Construction bite
• Retruding mandible as much as possible, generally edge to edge
• Vertical dimension: opened only enough to correct crossbite, allow wires to pass through, about 2mm in posterior region
Fabrication
Working model trimming
wax relief
wire forming
fabrication of acrylic portion.
Clinical management
• All margins are checked smoothness
• Fitting the appliance 1-2 weeks
• First visit: extending wearing time to 4-6 hours
• Second visit:exercises may be prescribed including speech and lip-seal
• Upper molars rest will be cut
Twin block appliance
tu
introduction
• Two pieces appliance
• Giving greater freedom of movement in anterior and lateral excursion
• The appliance can be worn full day
• Harness all oral functional forces especially the forces of mastication
• Correct the malocclusion rapidly
Construction bite
• Overjet≤10mm,bite may be activated edge to edge on incisors if the patient can posture forward comfortable
• Vertical dimension: 2mm interincisal clearance
Design and construction
Midline screw to expand the upper arch
Design and construction
retainer
Design and construction
Bite blocks
Design and construction
Inclined plane
Design and construction
Base plane
Design and construction
Labial bow
Stage of treatmentStage 1: active phase:twin block
Stage 2: support phase-anterior plane
Dolichofacial patients:non-trimming, prevent second molars extrusion
Branchfacial patients:trimming
Timing:1-2 months after the appliance was inserted
Method:trimming the upper block to leave 1mm clearance between bite and lower molar
Vertical control
trimming
Herbst
Removable appliances
• Producing tilting movements of individual teeth
• As an adjunct to fixed appliance treatment
• retention
Anterior bite plane
management
• The bite plane should be length enough to ensure the lower incisors bite on the bite plane.
• Add to the height of the bite-plane during treatment
Buccal capping
• Eliminating occlusion interference
• Dental incisors cross-bite
• Unilateral posterior teeth crossbite
Bilateral block
Unilateral block