Examples of functional appliances and Twin block Group 5 Huda, Zafirah, Marshitah, Marzura, Fatin, Haziq

Outline Introduction 4 examples of functional appliances Frankel appliance Bionator Herbst appliance Twin block Function Component Design

Introduction Functional appliance can be defined as removable or fixed orthodontic appliances that aim to utilize, eliminate or modify the forces generated by orofacial musculature, tooth eruption and dentofacial growth in order to alter skeletal and dental relationships. Effect dental (70%), skeletal (30%) Types: Tissue-borne Frankel appliance Tooth-borne (active) Twin block Tooth-borne (passive) Andresen appliance Myotonic Harvold activator Fixed Herbst appliance

EXAMPLES OF FUNCTIONAL APPLIANCE

Frankel appliance Functional regulator (FR). Use during mixed and early permanent dentition stages. Widely used in Class III mal. It produces changes in anteroposterior, transverse, and vertical jaw relationships Worn full-time basis for 18-24 months. Then, part-time basis until the fixed appliance are placed to align permanent teeth. Components; -Buccal shield -Labial bow -Labial pad -Palatal bow -Lingual pad -Canine loops

Removable appliance; monoblock Bionator Removable appliance; monoblock To correct an overbite by promoting lower jaw growth. Since it influences the growth of bone, the appliance should be used during a period of maximum growth. Generally, the younger the patient's age when it is used, the more change observed over a period of growth. This appliance is no longer effective at influencing jaw growth when patient reached skeletal maturity. Components; -Wire framework; labial bow -Acrylic bite block -Palatal bar

Herbst appliance Fixed functional appliance Helps correct jaw and tooth imbalances in which there is an retrognathic mandible. Stainless steel crowns attached to molar teeth with an expansion screw in the middle of the palate to help widen the upper jaw. A plunger guides the lower jaw into a more forward position, stimulating lower jaw growth and thus decreasing the overbite. It is usually worn for about 9 to 12 months, followed by an additional period of time in fixed appliances. Components; Stailess steel crowns/caps -Wire bands -Plungers -Expansion screw

Twin block Removable functional appliance. Made up of two components, an upper and lower plate, which works together to posture the lower jaw forward. Frees up the “locked-in” lower jaw and encourages it to grow to its fullest potential. The upper (and sometimes lower) plate may also have an expansion screw to widen the arch. Treatment with a Twin Block appliance typically takes 12 to 18 months. Components (ARAB); -Upper plate -Ball end clasp -Lower plate -Adams clasp -Expansion screw -Acrylic bite plane

FUNCTIONS OF TWIN BLOCK Two separate upper and lower appliances work together as one interlock at 70 degree angle set into the bite block posture the mandible forward into ideal class I position preset by wax registration Frees locked-in lower jaw, encourages it to grow to its fullest potential Can be used on people of all ages, but usually used on growing patients to treat an underdeveloped lower jaw

1. Active phase – Twin Block: 2 stage treatment: 1. Active phase – Twin Block: Reposition the mandible forward until overjet and overbite are corrected First molars will be in contact Maxillary and mandibular incisors will be nicely coupled Worn a minimum of 7 to 9 months to prevent development of dual bite Dual bite : 2 positions of bite and TMJ When teeth contact only at molars, condyle is positioned in fossa, grinding of teeth can cause pain and damage to teeth When teeth close properly, condyle out of fossa, resulting in pain to TMJ If teeth is positioned in midway position, pain and tension developed in the masseter and temporalis muscles

2. Support phase – Retainer or fixed appliance URA with steep anterior incline plane is used to retain the corrected incisor relationship until posterior occlusion is fully integrated. Usually takes 4 to 6 months and is continued for additional 3 to 6 months to allow the reorientation of the muscular complex.

INDICATIONS The basic indication is Class II division 1 malocclusion. The following is a good general selection criteria: 1. Permanent dentition and active grower 2. Uncrowded dentition with well-developed arches 3. 10mm or less overjet with normal to deep overbite 4. Improved facial aesthetic once the mandible is brought forward to class I 5. Normal growth direction

INDICATIONS To treat other types of malocclusion: TMJ therapy Class II division 2 Class I open bite Class III Lateral constriction of the arch Anterior/posterior arch length discrepancies TMJ therapy closed bite (deep bite)

Component Of Twin Block

- retraction of the maxillary incisors and appliance retention 1) Adam’s Clasps Used for retention Attach to the first primary molars and first permanent molars in mixed dentition If do not have first primary molars or first premolars, it would be better to delay the treatment  no adequate retention for the upper block. 2) Labial bow - retraction of the maxillary incisors and appliance retention

3) The Upper Block - covers the second premolars, first molars and second molars - angled at 70 degrees from mesial of second premolar, will interlock with the lower block. - upper block must be at least 5-6 mm thick. 4) Midline screw - used for lateral expansion of the maxillary arch to accommodate an advancing mandibular arch. -used when minimal expansion of the maxillary arch is required (4-5mm)

Upper arch Lower arch

Design Of Twin Block

Type 1

Standard Twin Blocks-Class II Div I (with good arch form) • Adams or Delta Clasps, and Anterior Ball clasps for good retention •Twin Blocks, at a 70º angle, to advance mandible • Upper Midline Screw: so upper arch can accommodate lower arch in advanced position

Type 2

Standard Twin Blocks-Class II Div I (with crowded lower arch) • Adams or Delta Clasps, and Anterior Ball clasps for good retention •Twin Blocks, at a 70º angle, to advance mandible • Upper and lower Midline Screws

Type 3

Stage II - Support Phase • Anterior Inclined Plane used to maintain the corrected AP and incisor relationship until buccal segments settle into full occlustion. *Molars must be in contact to begin Stage II

Type 4

Class II Div II Twin Block • Adams or Delta Clasps •Twin Blocks, at a 70º angle, to advance mandible • Upper and lower Midline Screws • Lingual Springs to move anterior forward To Open Bite: Reduce upper bite block as ilustrated above

Type 5

Class II Div II Twin Block “SAGGITAL” • Adams or Delta Clasps, and Ball clasps • Standard 70º Twin Blocks • Adjust screws ¼ turn per week to advance anteriors To Open Bite: Reduce upper bite block as ilustrated above

Type 6

Twin Block to Close the Bite • Adams or Delta Clasps • Standard 70º Twin Blocks • Tongue guard to prevent tongue thrust and act as Inclined plane to support the corrected incisor relationship • Lower Acryclic extended to 6’s with indicated clasps • Acrylic relieved lingual to anteriors to encourage reduction of open bite

References http://www.hughes-ortho.com/forms/bionator.pdf http://www.quintpub.com/PDFs/book_preview/B8845.pdf http://mcnamara.s3.amazonaws.com/Herbst%20Appliance.pdf Twin Block Appliance. Available from: http://www.aurumgroup.com/files/removable/C882-Twin_Block_Ortho_4_Eng-web7-2.pdf Roger A. The twin block appliance. Available from: http://www.orthoconcepts.net.au/pdfs/TWIN_BLOCK_HANDOUT.pdf Twin Block. Available from: http://wikisites.mcgill.ca/Dentalpedia/index.php/Twin_Block Principles of Appliance Therapy Operatory Edition. Clark, William. “Twin Block.” The American Journal of Orthodontics. January 1988.