Methods of Gaining Space. / orthodontic courses by Indian dental academy

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METHODS OF GAINING SPACE.

INDIAN DENTAL ACADEMY

Leader in continuing dental education

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Space required to Move teeth into ideal locations. Correction of crowding,

retraction,intrusion, leveling of curve of Spee, derotation of anterior teeth, correction of molar relation.


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SPACE CAN BE GAINED BY

Non extraction method Extraction method.Expansion

Interproximal reduction.Molar distalization


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When to employ the method of Non extraction for gaining space?Guide lines:

•8mm/less of crowding-mild to moderate space requirement.•Severely mesially and lingually tipped posterior teeth-constricted arches(no skeletal component of malocclusion).•No need to alter the facial profile.•Co-operative patient.•Growing patients-afford more space.www.indiandentalacademy.co

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A) M-B cusp tips of the upper 1st molar.

B) Buccal groove at the middle of the buccal surface of the lower molar.

Subtract B from AMean difference in normal

occlusion:Males: 1.6mmFemales:1.2mm

2. Ashley Howe’s index.

Estimation of need for expansion

Dental constriction with good skeletal transverse dimension.

Based on cephalogram ,model analysis: to quantify arch length tooth material discrepancy. Up to 5mm


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Expansion:

Coffin springs Slow expansion

Screws.

Removable

Fixed

RME Quad helix W arch Arch Wire

SkeletalDentoalveolar

Jack screws used in removable – slow expansion

In fixed- quad helix, w arch can be used.


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Coffin spring•Walter H. Coffin 1881

•Indications:Slow dentoalveolar expConstricted upper arch

APPLIANCE CONSTRUCTION:1.25mm hard round S.Steel wire.U or Omega shaped wire.Stands 1mm away from palate.Retention from Adam’s clasps on U6,U4 or E

Removable appliances:


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Appliance activation.

Range of activation 2-4 mm before insertion.

Disadvantage:Dislodgement of clasps from the teeth.Heavy intermittent force. Patient compliance.


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Expansion ScrewsBaseplate used as working part, divided and driven apart by screws.•An equal division-create reciprocal anchorage for both parts.•Unequal:larger-added anchorage for movement of smaller part/s.F/A more.•90 degrees-plates move apart by 0.2mm.•PDL-0.1mm on each side.•Schwartz- first to use this type of plate.•254types.but basic principles same.Encased screws

Skeleton screws

• SIZESMaxillary-broaderMandibular-narrower


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Skeleton type.

Bertoni screw.

Encased screw.


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Schematic sagittal section:


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Activation of the screws in removable appliance:

•1mm/complete revolution.•0.25mm of tooth movement/quarter turn.•Rate of active movement not exceed 1mm/month•Only twice a week-1mm bilateral movement.•Turn screw with appliance in mouth.•Don’t remove it for several hrs after activation-better chance of fit.


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All split appliances – only tipping tooth movement(edge of plate contacts each tooth at only one point) no couple.

Activation of screw produces heavy intermittent force.

Initial high and rapid decay- potential of damaging the tooth.

Limited indications .

Disadvantages of removable appliances.

USAGE WITH FUNCTIONAL APPLIANCES.


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Lower Schwartz appliance:Indications:Mild to moderate lower ant crowding,Lingual tipping of post teeth.Activation:once/week0.20 to 0.25mm of expn in midline.3-4months; gain 4-5mm of arch length anteriorly.PURPOSE: orthodontic tipping, uprighting. www.indiandentalacademy.co

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Upper Vs Lower expansion stability:

Upper – more stable. Lower – before canine eruption.8-

9yrs. Force elimination:Frankel regulator.Lip bumper.


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Rapid Vs Slow Maxillary Expansion.

Expansion across the suture

Rapid

Slow2 schools of thought - rate of palatal splitting:

1. Rapid expansion: 2-4weeks:min tipping & max skeletal displacement.

0.3-0.5mm/day. Force build up to 10-20pounds.2. Slow expansion: 1mm/week for 2-6months. 2-4pounds of

pressure –optimum.The ratio of skeletal to dental exp is 1:1 from the beginning.More physiological response.www.indiandentalacademy.co

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Rapid Maxillary Expansion:

•Skeletal expansion, separation of the mid-palatal suture• Maxillary shelves away from each other.

HISTORY:Emerson C. Angell 1860E.N.T Surgeons.Korhkaus and Andrew Haas in 1950’s


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Indications:

Unilateral/bilateral discrepancies. Skeletal/dental constriction. Gain arch length in cases of moderate

crowding. AP discrepancies-class II div I, class III. Inadequate nasal capacity- chronic respiratory

problems.


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Contra indications:

Single tooth cross bite Vertical growers-steep mandibular plane angle. Pre school children.(fig) Non compliant patients.


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Fig:


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Principle:

Rapid heavy force to teeth- no sufficient time for teeth to respond.

Transferred to the suture, which opens.

While teeth move minimally relative to their supporting bone.


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Sutural patency.•Vital to RME.•when and how quickly synostosis takes place?•Studies.•Earliest – 15yr girl. Oldest unossified-27yr woman.•In general, bony spicules : 15-19yrs.•Greater obliteration posteriorly.•On avg, 5% closed by age of 25 yrs.•Optimal age-before 13-15yrs. Later unpredictable.•OCCLUSAL RADIOGRAPH.www.indiandentalacademy.co

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Effects of RME

On the maxilla.



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Krebs (1964) : 2 halves of maxilla rotate in Sagittal

Coronal

Coronal plane: 2 halves move away from each other.Fulcrum of rotation around the fronto-maxillary suture.

Sagittal plane: rotate in downward and forward direction.

Final position: unpredictable. Partially/complete relapse.www.indiandentalacademy.com

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RME in deciduous and mixed dentition produces, downward and forward rotation of the palatal plane. Increase in the upper

anterior facial height(N to ANS) Point A is also moved anteriorly.www.indiandentalacademy.co

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Triangular split of maxilla.A. Transverse view B. Frontal

view


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Coronal Section at the level of 1st molars

The mid palatal suture opens with an inverted V shape ,the maxillae separate, the alveolar ridges tip and bend buccally,the teeth move bodily and also tip within the alveoli,and the mucoperiosteum of the palate stretches.


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The typical triangular opening of the median palatal suture confirms the separation of the maxillary process during the RME.similar opening-in superio-inferior direction.Max-oral side,less on nasal side.

The median palatine suture is repaired totally after 90 days of active phase of expansion.

Greater opening


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Evident splitting of the maxillaRepresents the so called Orthopedic effect.

Nasal cavity widened. Floor and lateral walls by maxillary process.


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1. Before treatment. 2. During treatment. 3. After treatment

1.

2.

3.


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Effects on:Maxillary anterior teeth: diastema. ½ the distance the screw has opened.By 3-4months closes.Maxillary posterior teeth:fig

Mandible: swing downwards and backwards.(disagree)


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Changes in angle of tooth inclination

1st during active RME2nd after RME during controlled

relapse.

.’. Need to overcorrect to compensate for the

subsequent up righting of the teeth.


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Effects On Nasal Air Flow: Anatomically:Increase in width of nasal cavity at the

floor,outer walls of the nasal cavity move laterally. Air flow resistance reduced by 45% thereby improving

nasal breathing.

Total Effect: Increase in the inter nasal capacity.

Wertz(1968): opening the palatal suture for purpose of increasing the nasal airway, cannot be justified unless the obstruction is in the lower anterior portion of the cavity accompanied by a relative maxillary width deficiency.


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Types of RME Screws.

Tooth and tissue borne Tooth borne

Derichsweiler Haas Issacson Hyrax

BandedBonded


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Derichsweiler appliance.

Retentive tags


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Haas Appliance

1.2mm S.steel wire


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Hyrax type of Screw.


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Issacson expansion applianceUsing Minne expander.

A coil spring having a nut to compress the

spring.

ACTIVATIONExpander activated by closing the nut so that

the spring gets compressed.


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Bonded RME1. Cast Cap Splints.

2. Acrylic cap splints.


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Bonded Rapid Palatal Expansion appliance.


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Activation Schedule:TIMMS:

•Upto 15yrs: 90 degrees rotation in morning and evening.•Over 15yrs: 45 degrees activation 4 times a day.•Over 20yrs: initial 90 degrees, 45 degrees morning and evening.Surgical intervention.

ZIMRING and ISSACSONYoung growing patients: 2 turns/day for 4-5 days.later 1turn/day till desired expansion.Non growing adult: 2 turns for 1st two days, 1turn/day for next 5-7 days. And 1 turn every alternate day.www.indiandentalacademy.co

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How much to expand?

STABILITY:

1. Growing patients.

2. Before the eruption of canines.

3. Self retention of cross bite correction.www.indiandentalacademy.com

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Surgery as an adjunct:

•Unusual resistance to separation-surgical intervention.

•Females over 16yrs, males over 18yrs.

Surgery ( SARPE ) / surgery + RME

(distraction osteogenesis)

Palatal osteotomy.

Lateral maxillary osteotomy.

Anterior maxillary osteotomy. www.indiandentalacademy.co

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Clinical Tips: 4/4 Xn postpone. No prior orthodontic

movement. Activate, 15-30min

after insertion. String/dental floss tied. See patient at regular

intervals. Monitor with weekly

occlusal radiographs.

Open within 7-10 days. Retention: 3-6months. TPA can be placed. Symptoms on

premature removal. Dizziness,heavy

pressure, face.blanching of soft tissue. 19hrs.

Always seated.


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Fixed Expansion appliancesQuad Helix

Evolved- original coffin loop.4 helices - increase range and springiness of the appliance.Anterior helices bulk-serve as reminder.

2 types: fixed removable

Indications:•Bilateral posterior cross bite. •Finger sucking habit.


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38 mil S.Steel wire.Li wire contact teeth in crossbite.1-2mm distal.

•Over correction.

•Soft tissue irritation.

•3 months of retention.

Molar rotation

Slow dentoalveolar expansion. 2mm/month.1mm on each side,until cross bite over corrected.In primary and early mixed dentition- skeletal midpalatal splitting.

ACTIVATION


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W ARCH• Originally used by Ricketts.•36mil S.Steel wire.•1-1.5mm short of palatal soft tissue.

ACTIVATION: •2mm/month. Duration 2-3months.•Remove and then activate.•3 months retention.


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Unequal W arch to correct true unilateral maxillary

constriction.Side to be expanded- fewer

teeth than the anchorage unit.


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Nickel Titanium palatal expander-Wendell V. Arndt JCO 1993 march

Tandem loop Ni Ti palatal expanderLight continuous forces.Simultaneous up righting, rotating and distalization of the molar.Transition temp 94 FSizes-8 diff molar widths.27mm – 47mm.force 180-300g


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Degree of compression at 20 degrees below the transition temp. B. effect of shape memory when the wire is warmed to body temperature.

. Passive appliance. B.initial activation and insertion for expansion and distal molar rotation. C. After expansion and

rotation correction.www.indiandentalacademy.com

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Nitanium Palatal Expander 2

Maurice C. CorbettJCO April 1997.

Uniform slow continuous forces.

Maintains the tissue integrity.

Regeneration = rate of expansion.

ACTION

Shape memory and transition temp.


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APPLIANCE SELECTION Available in 10 sizes, from 26mm to 44mm. Determination of the size of expander. NPE 2 delivers a force of 350g in 3mm increments. If 4mm expansion ,initial force higher, later return to 350g

once 3mm expansion occurs. Preprogrammed, .’. Self limiting. TETRA FLUOROETHANE refrigerant spray. In mouth begins to warm,NiTi stiffen-shape memory. Completed in 2-4months. Retention-2-3months.


56After 3 months of expansion with NiTi palatal expander 2

After Initial placement.

Ligature should be tied.


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Lip Bumper

Gain arch length in mild to moderate crowding cases.

Stainless steel 36mil in0.045”tubing or coated in acrylic and inserted into the molar tubes.

The lateral arms remove the resting pressure of the buccal musculature .’. Allow the unopposed action of tongue – increases arch width

Bodily forward movement of incisor, labial flaring, distal tipping of molars.

Pressure exerted on the shield-100-300g

LIP BUMPER.


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CETLIN’S LIP BUMPER

Reinforce anchorage.

Molar distalization.

Middle of the crown.Canine 2mm. Premolar

3mm.


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DENHOLTZ LIP BUMPER /muscle anchorage appliance.

Upper lip contraction and exercises, exert distalizing force via

the coil spring.


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T.P.A

Functional appliances:Functional Regulator.

•0.036” S.Steel wire.

•Fixed or removable.

•Prevents mesial migration of U 6.

•Molar rotation. Maintain the inter molar width.


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5mm of expansion in the molar and the canine area.

Arch Expansion in Fixed Appliances:

•In conjunction with TPA / quad helix

Overlay wires used for arch expansion.


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PROXIMAL STRIPPING. Proximal surfaces sliced to reduce the M-

D width of the teeth. Conservative method-mild to moderate

crowding.3-5 mm of space requirement. Ballard – 1944. Routinely carried out in the lower

anterior region.


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Indications: Contra Indications:

3-5mm. Bolton’s excess. Aid in retention. Maintain the profile. Maintain Class I canine and

molar relation. Carey’s analysis:0-2.5mm

Young patients- high pulp chamber. High caries index. Poor oral hygiene. Enamel hypoplasia.

Advantages:•Borderline to non Extraction.

•A favorable overjet and bite can be estbl.(match the U and L tooth material)

•More stable results –contact area broadened.www.indiandentalacademy.com

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Disadvantages:

Roughened proximal surface- plaque. Ledges, grooves. Excess tooth material reduction. Increased caries susceptibility Sensitivity. Alteration of the tooth morphology. Loss of contact- food impaction.

Conventional

Air rotor stripping.Methods


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Amount of proximal stripping:

Not more than 50% of enamel thickness

1. Metallic abrasive strips.

2. Safe sided carborundum discs.

3. Long thin tapered fissure bur.


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Air rotor Stripping method (ARS) John J. Sheridan in 1985. Removal in buccal segments (enamel thickest) 3-8mm of space requirement. More space than conventional. 1mm per contact point. No risk of cutting gingival tissue.


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Diagrammatic representation of ARS technique



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Topical fluoride applicationPolishing.

Useful therapeutic tool if done judiciously.

Excessive enamel reduction is irreparable;

Proximal surfaces must be shaped as naturally as possible.

Polishing.

Done properly- no effects on interproximal tissue and bone.


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Methods of Gaining Space. / orthodontic courses by Indian dental academy

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