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R.M.E. IN

ORTHODONTICS

Presented By: Dr. Himali GuptaP.G. Ist Year Student

CONTENTS

• INTRODUCTION• CLASSIFICATION• RME• SURGICAL EXPANSION• DISADVANTAGES• CONCLUSION

• REFRENCES

INTRODUCTION

• Emerson Collon Angell reported on the procedure in 1860.

• This approach was opposed strongly by McQuillen (1860) and Coleman (1865).

• Haas reintroduced rapid maxillary expansion.

• Palatal expansion is helpful in other surgical disciplines as oral ,ENT and plastic surgery

• Word “Expansion” refers to lateral enlargement of dental arches by orthodontic forces :

• (a) Direct forces• (b) Indirect forces • First objective is correction of discrepancy in

transverse dimension.

• This can be achieved by “Rapid Maxillary Expansion”

Defintition:

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

• These appliances are the best examples of true orthopedic expansion.

ANATOMY:• Articulation of maxilla :• Cranial • Facial

• Sutures:

In infancy

In early adolescence

In Late Adolescence

INDICATIONS

Dental indications: 1. Posterior Cross bite (unilateral/bilateral). 2. Tranverse dicrepancies.3. Activation of the circummaxillary suturs .4. Cleft palate patients.5. In patients with tooth size – arch size dicrepancies.

Medical Indications (Given by Gray and Brogan)

1. Poor Nasal airway2. Septal Deformity3. Recurrent ear, nasal (or) sinus infections4. Allergic rhinitis5. Asthma

CONTRA - INDICATIONS:

1. Single tooth cross bites.2. In patients who are un co-

operative.3. Skeletal asymmetry of maxilla &

mandible & Adult cases with severe antero posterior skeletal discrepancies.

4. Vertical growers with steep mandibular plane angle.

5. Anterior open bite.

EFFECTS OF RME:Maxillary skeletal effect: • On activation compresses the periodontal

ligament and bends the alveolar process buccally.

Amount of expansion achieved:

• An increase in maxillary width upto 10mm can be achieved by RME.

• The rate of expansion = 0.3 - 0.5 mm per day.

• Effect on Alveolar bone: Bends slightly.

• Effect on Maxillary Posterior teeth: Buccal tipping and extrution.

• Effect on Mandible: Downward & backward rotation of mandible.

• Effects of RME on nasal cavity: Widening of conchae.

• During RME, maxilla moves downward and forward and simultaneously mandible moves downward and backward (Wertz 1977).

• Biedermann (1973) explained buttressing.

R.M.E.

CLASSIFICATION1. Removable Appliance2. Fixed Appliance a) Tooth borne - Derichweiler - Hass b) Tooth & tissue borne - Isaacson - Hyrax

WILL AND MUHL:I Jackscrew Appliances: 1. Tooth borne, Hyrax appliance 2. Tissue borne, Hass applianceII Removable Expanders. Removable jack screw

appliancesIII Non screw expanders A) Quad Helix B) Transpalatal archIV Slow expansion: Minne expanderV Functional appliances

Banded Appliances:

•Banding is done•Wires may be soldered.•Commonly used appliances are :

1. Derichsweiler

2. Hass

3. Isaacson

4. Biedermann

1) Derichsweiler type :

2). Hass type :

3. Isaacson type :

4.Biedermann type :

Bonded appliances : • Splints can be of two types:

• 1. Cast cap splints 2. Acrylic Splints

• Cap Splints : (Hershey et al 1976)

• These are usually cast in silver / copper alloy.

Acrylic splints :

• Made of poly methyl metha-acrylate•Mondro et al (1977)have described an all acrylic form of cap splints and inter connection with a screw embedded in the midline.

A typical expansion screw :

The pattern of threading on either side is of opposite direction. Thus turning the screw withdraws it from both sides simultaneously.

THE BUTTERFLY EXPANDER FOR USE IN THE MIXED DENTITION:

• Follows basic design of Hass

• The location high in the palatal vault.

• The butterfly design thus minimizes posterior tipping and extrusion.

A FAN-SHAPED MAXILLARY EXPANDER:

• Schellino and Modica have designed a “spider screw” that works asymmetrically and allows fan opening.

Activation Schedule:1. Schedule by Timms: Patients </= 15 yrs: 90 degree rotation in morning and evening. >/= 15 yrs: 45 degree activation 4 times per day.

2. Schedule by Zimring and Isaacson: Young growing patients: 2 turns per day for 4- 5 days, followed by 1 turn per day till expansion is achieved. Non growing adults: 2 turns per day for 2 days, then 1 turn per day for 5-7 days, followed by 1 turn every alternate day, till expansion is achieved.

3. Mc Namara and Brudon: Prefer a one per day activation schedule till expansion is obtained, in order to avoid nasal distortion which has been associated with 2 expansions per day protocol.

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REQUIREMENTS OF AN RME APPLIANCE

• Rigidity • Tooth utilization • Expansion( dilating unit and action) • Economy of time and material • Hygiene

RIGIDITY (RESISTANCE TO ROTATION)

• A rigid appliance will exert parallel opening and produce expansion at a greater distance from the appliance than one which is flexible and produces expansion mainly by lateral inclination.

2). Tooth Utilization: (No. of teeth included in appliance)

a). Load distribution :

• Best to incorporate as many teeth as possible.

• Bands can be cemented simultaneously only to a few teeth because of difficulties of multi alignments whereas splints can be adapted to all teeth.

b). Appliance retention:

• Depends on area of adhesion b/w the teeth & appliance, the precision of fit (or) thickness of the adhesive agent & shape of clinical crown.

• Bands may be superior to cap splints in view of their closer adaptation.

3) Expansion : (Dilating unit & action)

The dilating mechanism :

1. spring – decreases rigidity and control

2. Screw – should have adequate length

4) Hygiene :

• Given the lowest priority, as any deleterious effects are superficial & reversible.eg beiderman type

• Cap splints should be fixation of choice.

CLINICAL MANAGEMENT OF RME

• a).Fitting the appliance :

• Cast cap splints – check cleanliness especially, of the fitting surface to secure good adhesion.

• Check the direction of the screw for opening.

• Check the seating of appliance.

b) Cementation of appliance:

• Only when satisfied then only proceed with cementation.

• Ames black copper cement is used.

• Allow the cement to become hard for at least 1/2 hr. to assure complete setting, before strain is imposed by activation

C. Instructions : (Initial)

o The appearance of midline diastema . o Difficulties in speech and mastication must be

mentioned together with points on oral hygiene.

o Patients have been classified into 3 age groups:

1. Upto age of 15 years2. Age 15 – 20 years3. Age over 20 years

1. Upto age 15 years : 180o per day 90o morning and 90oevening for 1 week.

2. Age 15 – 20 years : 180o per day 45o four times a day for 1 week.

3. Age over 20 years: 90o per day 45o morning and 45o

evening for 1 week.

4. For above 25 : Surgical opening of suture followed by revisit after 3-4 days .

• D). Pain during RME:

• Desired expansion in the short time requires strong forces which often produces painful effects.

• The threshold levels of pain very among individuals.

• Two factors generally are responsible:1. Rigidity of facial skeleton

2. Mechanical interlocking and synostosis of mid palatal suture

• E). Instructions : (Subsequent)

• First ask the patient & person turning the screw for any difficulties.

• Then check the central incisors for diastema.

• Then examine the screw to see how much thread is exposed.

• If all is well, ask the patient to continue

• Ask the patients about pain ;it generally disappears if the suture is open.

• No 45 degree turn of the screw before the pain has dissipated.

• Patients over 20 years it is difficult to differentiate b/w the pain from an unopened suture & that from skeletal rigidity.

• If non opening of suture, surgical freeing should be considered.

• F) How much to expand:

• Study's show that, between 1/3rd & ½ of the expansion was lost before stability was eventually reached.

• Expansion should stop when the maxillary palatal cusps are level with the buccal cusps of the mandibular teeth.

Forces of relapse :

• After RME, the teeth effect a partial relapse by rotating inwards about their bases

• The factors causing relapse are: 1.Genetic – no assistence2.Environmental - The size & shape of the

bones are determined by function.

Expansion generated:

• Most potent factors causing relapse are due to stretching of soft tissue & the deformation of the hard tissue under the powerful forces built-up by RME, but can be controlled by retention.

• Forces can be sub-classified into 3 groups based on nature & time scales:

a) Elastic recoil - shortest active effect

b) Repair & reorientation - A longer process

than elastic recoil

c) Bone remodeling - Time scale is long

Retention : • The objective - to hold the expansion

while all those forces generated by expansion appliance has decayed.

• A palate covering retainer is satisfactory.

• Heavy labial wire with headgear maintains lateral expansion.

• Long retention period of atleast 2 yrs after removal of

expansion appliance is needed.

• Even with the appliance worn according to instructions there can be slippage & some relapse creeps in.

• About 9 months after expansion, wear of retention plate can be reduced from full time to half time (usually evenings & nights)

Integration:

• Malocclusion often has a different appearance & its easier to treat after RME as result of changed maxillo-mandibular relationship.

• Extractions should be be done

untill RME

STABILIZATION• The clinician has 2 factors under his control

to achieve a satisfactory result:

1. Over expansion - to allow for the inward

tilt of the teeth.

2. Length of retention - to allow for the

stretching of tissue etc.,

• Two environmental forces can be outlined which largely will determine the final occlusal relationship.

• 1). Bucco- lingual pressures

• 2). Articulation

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RAPID MAXILLARY EXPANSION OF CLEFT LIP & PALATE

RME in cleft palates RME is carried out only in those cases where cleft has been closed surgically.

ANATOMY :

• Normal lateral relationship of posterior teeth, with anterior collapse.The maxillary collapse is stopped by the turbinate bones in contact with the nasal septum. The nasal airway is reduced.

• By moving the maxilla laterally-nasal airway is enlarged- reduction in nasal resistance.

• Subtelny (1957), found that, the width between the pterygoid hammuli were slightly wider than in non cleft subjects.

Appliances :

The basic principles of design apply equally to clefts.

• The most common problem, is the anterior collapse, so that parallel (or) near parallel expansion is undesirable.

• Differential expansion puts considerable flexural strain on the screw in the horizontal plane & may result in fracture of the screw (or) displacement of the appliance.

•The greater the collapse, the less space available for the screw, where the longest possible length of thread is needed.

Bone grafting :

• Bone grafting is required if RME is used in correction of malocclusions associated with cleft.

• RME & consequent bone grafting are not carried out until early teens.

• Jolleys et al 1972, Robertson et al. 1972 &1978 reports early grafting suggest inhibition of growth.

Treatment summary:

• Normally RME is done before extraction (or) other forms of appliance therapy.

• RME in CLCP , usually produces less discomfort then in normal palate subjects of equivalent age. (Jentoff 1965)

•The usual 3 months of fixed retention phase with expansion appliance left in-situ is advised.

• Undesirable situation - the opening of oro-nasal fistula.

• Within the cleft, teeth often are absent (or) unable to take up satisfactory position in arch because of lack of supporting bone.

• These teeth are frequently extracted & the resulting space & fistula are covered by prosthesis

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SURGICAL ASSISSTED MAXILLARY EXPANSION

Surgical freeing of the maxilla

1) Age at surgery : Resistance in the maxilla to separation may be traced to 3 causal factors

1. Mid palatal synostosis

2. Mid palatal inter locking

3. Circummaxillary rigidity

• 5% sutural ossification with mechanical interlocking can be tolerably broken by RME without surgical assistance, when added to the general bony rigidity of the maxilla & their surrounding structures.

• All RME patients between 20-25 years must be treated with utmost respect for early sutural closure.

• At 15-20 years range, surgery can be considered.

2). Surgical techniques:

Dennis Vero, has developed a series of operations in increasing stages of osteotomies to cope with palatal synostosis & progressive rigidity of facial skeleton.

The tech has been described in 3 stages: Stage 1 A and BStage 2 A and BStage 3 A and B

Stage I A: Palatal osteotomy used if patient age is 25yrs & over (or) younger if RME has been tried with appliances failed.

Advantage :

1. A single flap, which is easier to handle and reposition.

2. Soft and hard tissue wounds are not contagious, healing is better

Stage IB : Bilateral osteotomies of hard palate there are bilateral buccal crossbite and in same conditions as 1A.

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STAGE 1

• Stage II A: Over the age 30 yrs - lateral osteotomies in addition to palatal ones.

• Stage II B : In cases of bilateral buccal crossbite lateral osteotomies extended to both sides.

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STAGE 2 (OVER THE AGE OF 30)

The soft tissue incision is made in the zygomatic arch forward to a point over apex of the LI and down to the gingiva of the CI

With this exposure of the lateral wall, the maxillary cut is made from the piriform aperature , through the anterior and lateral wall of the antrum and across the buttress at the base of the zygomatic arch, to stop at the tuberosity.

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STAGE 3 (OVER THE AGE OF 40)

The horizontal incision is made in the alveolar mucosa is made as in stage 2 but the downward portion is made obliquely across the midline to give access to the ANS

The bone is cut from the piriform aperture to the midline beneath the ANS and is continued down between the CI.

Carried along the floor of the nose but it doesn't meet the palatal incision.

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CONCLUSION Expansion of the arches has seen its ups and downs in the past.

More and more documentation of the effects and stability of this procedure has thrown a new light on its clinical application.

Whether it is slow or rapid expansion, proper diagnosis and case assessment is very essential to ensure consistent results. As more and more cases are being treated without extractions due to profile considerations, expansion of the arches forms a valuable adjunct to treat a wide variety of clinical presentations.

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REFERENCES

1. Rapid maxillary expansion- D. J. Timms

2. Contemporary orthodontics- Proffit (3rd ed)

3. Orthodontics and dentofacial orthopedics James A Mc Namara, Brudon

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THANK YOU