Arch expansion

BHARATH REDDY .M

Expansion of palate was first achieved by E.C .ANGELL in 1960.

An apparently complex but simple procedure in orthodontics is palatal expansion.

It is broadly classified as -rapid -slow

Rapid maxillary expansion

It is a skeletal type of expansion that involves the separation of mid-palatal suture and movement of the maxillary shelves away from each other.

histroy

1860› E.C. Angell Introduce the RME procedure

1877 -walter coffin introduced a coffin spring for arch expansion

1960s› Haas and korhkaus made study of the RME› RME gained more attention

› Surgically assisted RPE – by Starnback, 1966

INDICATIONS

POSTERIOR CROSS BITE ASSCOIATED WITH REAL OR RELATIVE MAXILLARY DEFICIENCES.

CLASS III MALOCCLUSION OF DENTAL OR SKELETAL CAUSE.

CLEFT PALATE PATIENTS WITH COLLAPSED MAXILLARY ARCH.

IN CASE REQUIRING FACEMASK THERAPY. THE MEDICAL INDICATIONS LIKE NASAL

STENOSIS ,POOR NASAL AIRWAY,SEPTAL DEFORMITIES,RECURRENT EAR AND NASAL INFECTION ,ALLERGIC RHINITIS,D.N.S

The effect of rapid maxillary expansion

Maxillary skeletal effect:-The maxillary posterior teeth are used as a handles to apply a transverse reciprocal force so as to open mid-palatal suture.-Force employed for this procedure is very high.-On activation of this appliance it compresses the PDL and bends the alveolar process bucaally and opens the mid – palatal suture.-Opening of mid palatal suture is fan shaped with maximum opening at the incisor region

Amount of expansion achieved: -an increase in maxillary width upto 10mm can be achieved by R.M.E . -the rate of expansion is about 0.2 to 0.5 mm per day. Effect on alveolar bone: -the alveolar bone in the area adjacent to the anchor teeth bends slightly. Effect on maxillary anterior teeth: -appearance of midline spacing between the two maxillary central incisors is the most reliable clinical evidence of the maxillary separation Effect on maxillary posterior teeth: -they used as anchors in R.M.E . - the teeth show buccal tipping. Effect on mandible: -there is downward and backward rotation of the mandible this is accompanied by slight increase in mandibular plane angle-the mandibular rotation is due to extrusion and buccal tipping of maxillary molars.

Effect on adjacent cranial bones and sutures:

-the bones of the cranium such a s parietal and occipital were also found to be displaced. Effect on nasal cavity : -an increase in intra nasal space occurs due to outer walls of nasal cavity moving apart . -air flow resistance is believed to reduce by 45-60% therby improving nasal breathing.

Types of appliances used

Broadly they can be classified as 1.removable appliances 2 .fixed appliances a. tooth bone b. tooth and tissue bone

REMOVABLE APPLIANCES

A REMOVABLE TYPE OF RAPID MAXILLARY EXPANSION DEVICE CONSISTS OF A SPLIT PLATE WITH A MIDLINE SCREW

THE APPLIANCE IS RETAINED USING CLASPS ON THE POSTERIOR TEETH .

DISADVANTAGES : - NEED FOR PATIENT CO OPERATION -DIFFICULTY IN RETAINING PLATE IN THE MOUTH.

FIXED APPLIANCES

THIS ARE MORE RELIABLE AND FOUND TO PRODUCE COSISTENT SKELETAL EFFECTS .

THEY ARE OF TWO TYPES - TOOTH BORNE: 1.ISAACSON TYPE 2. HYRAX TYPE - TOOTH AND TISSUE BORNE 1.DERICHSWELIER TYPE 2. HASS TYPE

DERICHSWELLER TYPE: - 1ST PREMOLARS AND 1ST MOLARS ARE BANDED -WIRE TAGS ARE SOLDERED ON TO THE PALATAL ASPECT OF THE BANDS - THE WIRE TAGS GET INSETED INTO THE SPLIT PALATAL ACRYLIC PLATE INCORPARATING A SCREW AT ITS CENTRE.

HASS TYPE:

-THE 1ST PREMOLAR AND MOLAR OF EITHER SIDE BANDED . - THICK STAINLESS STEEL WIRE OF 1.2MM DIAMETER IS SOLDERED ON THE BUCCAL AND LINGUAL ASPECT CONNECTING THE PREMOLAR AND MOLAR BANDS.- LINGUAL WIRE KEPT LONGER TO EXTEND ANTERIORLY AND POSTERIORLY AND WIRE BENT PALATALLY FOR EXTENSION IN TO ACRYLIC WHICH DOES NOT EXTEND OVER RUGAE.

ISAACSON TYPE : - TOOTH BORNE TYPE WITHOUT ACRYLIC PALATAL COVERING - MAKES USE OF A SPRING LOADED SCREW i.e., MINNE EXPANDER. - 1ST PREMOLARS AND MOLARS BANDED AND METAL FLANGES ARE SOLDERED TO THESE BANDS ON BUCCAL AND LINGUAL. - EXPANDER CONSIST OF A COIL SPRING AND A NUT . - EXPANDER ACTIVATED BY CLOSING THE NUT

HYRAX TYPE : -MAKES USE OF A SPECIAL TYPE OF ASCREW THAT IS HYRAX.- SCREW HAS HEAVY GUAGE WIRE EXTENSIONS THAT ARE ADAPTED TO FOLLOW THE PALATAL CONTOUR AND ARE SOLDERED TO PREMOLARS AND MOLARS.

DESCRIPTION OF A TYPICAL EXPANSION SCREW

IT CONSIST OF AN OBLONG BODY DIVIDED IN TO TWO HALVES.

EACH HALF CONSIST OF A THREADED INNER SIDE WHICH RECIEVES ONE END OF A DOUBLE ENDED SCREW .

SCREW HAS A CENTRAL BOSSING WITH FOUR HOLES , WHICH HAVE A KEY i.e., USED TO TURN THE SCREW.

90DEGREES TURN – LINEAR MOVEMENT OF 0.18 mm.

ACTIVATION SCHEDULE

SCHEDULE BY TIMMS: - FOR PATIENTS: - UPTO 15 YRS -90 DEG ROTATION IN MORNING AND EVENING.

-OVER 15 YRS -45 DEG ACTIVATION 4TIMES A DAY.

SCHEDULE BY ZIMRING AND ISAACSON: - YOUNG GROWING PATIENTS: 2 TURNS/DAY FOR 4 -5 DAYS & LATER 1 TURN/DAY TILL DESIRED EXPANSION IS ACHEVIED .

- FOR NON GROWING ADULT PATIENTS:2TURNS/DAY FOR FIRST 2 DAYS & 1TURN/DAY FOR NEXT 5-7 DAYS & 1TURN EVERY ALTERNATE DAY TILL DESIRED EXPANSION

CONTRAINDICATIONS

SINGLE TOOTH CROSS BITE UN CO -OPERATIVE PATIENTS AFTER

OSSIFICATION OF MID PALATAL SUTURE.

SKELETAL ASYMMERTY OF MAXILLA & MANDIBULE.

VERTICAL GROWERS WITH STEEP MANDIBULAR PLANE ANGLES.

PERIODONTALLY WEAK DENTITION.

SLOW EXPANSION

RESULTS ARE MORE STABLE WHEN MAXILLARY ARCH IS EXPANDED SLOWLY AT A RATE OF 0.5 TO 1mm/week.

FORCES GENERATED BY SUCH PROCEDURES ARE MUCH MORE LOWER i.e.,2- 4 POUNDS AS AGAINEST 10-20 POUNDS GENERATED DURING R.M.E

TREATMENT MAY BE COMPLETED IN 2-5 MONTHS (1-2 WEEKS IN R.M.E)

APPLIANCES USED

JACK SCREWS: - USED FOR BOTH RAPID AND SLOW EXPANSION - BUT WITH MORE SPREAD OUT ACTIVATION SCHEDULE IN SLOW EXPANSION

COFFIN SPRINGS: - DESIGNED BY WALTER COFFIN - IT IS A REMOVABLE APPLIANCES - IT CONSIST OF OMEGA SHAPED WIRE OF 1.2mm THICKNESS PLACED IN MID PLATAL REGION. - FREE ENDS OF OMEGA WIRE ARE EMBEDDED IN ACRYLIC COVERING SLOPES OF PALATE. -ACTIVATED BY PULLING TWO SIDES A PART MANUALLY. - ALSO ACTIVATED BY USING THREE PRONG PLIERS.

QUAD HELIX

- IT IS USED TO EXPAND A NARROW MAXILLA - INCORPORATES FOUR HELICES THAT INCREASES WIRE LENGTH ,FLEXIBILITY & RANGE OF ACTION.- 0.038 INCH WIRE IS SOLDERED TO BANDS ON 1ST MOLAR.- FOUR HELICES – A PAIR ANTERIOR - A PAIR POSTERIOR- PORTION OF WIRE - BETWEEN ANTERIOR HELICES IS CALLED ANTERIOR BRIDGE - BETWEEN ANTERIOR AND POSTERIOR IS CALLED PALATAL BRIDGE.- FREE WIRE ENDS ADJACENT TO POSTERIOR HELICES CALLED OUTER ARMS WHICH REST AGAINST LINUAL SURFACE OF BUCCAL TEETH AND SOLDERED TO LINGUAL ASPECT OF MOLAR BANDS

THANK YOU