Space Maintainer Primary Dentition Final

8/13/2019 Space Maintainer Primary Dentition Final

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Space maintenance in theprimary dentition

Dr. Ola M Omar

Professor of Pediatric Dentistry,Taibah University/ Cairo University


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Lecture outline General considerations

Appliance therapy

Band and loop

Lingual arch

Distal shoe Removable appliances


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Characteristics of normal occlusion in the

primary dentition:At 3y years Spacing between primary teeth

A- Incisor spacing

B- Primate space

C- Spacing between primary molars

Molar relationship

A- Flush terminal planeB- Mesial step

C- Distal step

Normal overbite


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Primate spaceMesial step

Good spacing


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THE THREE TYPES OF TERMINAL PLANES

FLUSH PLANE MESIAL STEP DISTAL STEP


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The premature loss of a primary tooth has adeleterious effect on the occlusion. Proper

management of space problems in theprimary and mixed dentition stages canprevent unnecessary loss in the arch length.


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Effect of premature loss Why is the tooth maintained in its

correct position in the dental arch?


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The rate and extent of mesial or distal drift isinfluenced by the degree of crowding in the

dental arch, the primary tooth extracted andthe age of the patient.

In general the earlier the primary tooth isextracted the greater the opportunity of

drifting of teeth.


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Anterior tooth loss Loss of anterior teeth is due to caries or

trauma

Drifting of anterior teeth and space loss isminimal.

Loss of canine is rare

Reasons for replacement of primary incisors:Space maintenance, function, speech,esthetics.


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Posterior tooth loss Loss of inter-proximal contact as a result of

caries causes space loss

If the first primary molar is lost during activeeruption of first permanent molar, a strongforward force will be exerted on the secondprimary molar which tips into the space

required for the eruption of the firstpremolar.

Premature loss of second primary molar leadsto mesial drifting of first permanent molar

and impaction of second premolar.


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Space maintenance

Process of maintaining space previouslyoccupied by a tooth or several teeth.


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Definition of space maintainer

Appliances used to maintain space created by

premature loss of primary teeth till eruption of

permanent successor or Extraction of

permanent teeth till construction of fixed

replacement


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Requirements of space maintainer

Easy construction & placement

Hygienic , Durable

Prevent abnormal tooth position Maintains mesio-distal and vertical

dimensions of the space.

Does not interfere with tooth eruption.

Does not interfere with natural growth.

Provides esthetics in case of anteriortooth loss.


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Indications for space maintainers(factors affecting placement)

1. Time elapsed since loss

2. Dental Developmental Age

( chronological age?)

3. Amount of bone ( 4-5 monthsto move through 1 mm bone)

4. Degree of root development( if started accelerate eruption)


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5. Sequence oferuption

6. Delayederuption

7. Congenital

absence

If D lost and 2erupting

If E lost and 7erupting before 5


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Space maintainers for missingprimary molars

Band and Loop space maintainer

Indications

Advantages

Disadvantages

Construction


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Band and loop space maintainer

Indications:

In case of unilateral single tooth loss;

usually the first primary molar or thesecond primary molar after the eruptionof first permanent molar.

Bilateral loss of a primary molar beforethe eruption of permanent incisors

The band is adapted on the tooth distal

to the space.


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Advantages:

Easy to construct.

Inexpensive.

Gives room for erupting permanent teeth.

Does not need patient compliance.

Can be used for very young patients.

Disadvantages:

Does not restore masticatory function.

Does not prevent over eruption of opposing

teeth.


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5- Adapt a stainless steel wire of 0.7 mm into aloop to fit the band and alveolar ridge. Thelop should paralel edentulous ridge 1 mm off

gingival tissues and contact the distalsurface of the adjacent tooth at the contactpoint. The BL dimension 8 mm to allowpermanent tooth eruption freely.

6- Solder the loop to the band on the stonemodel.

7- Smooth and polish the appliance.


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8- Fit and adjust appliance if necessary.

9- Cement the appliance onto dry clean

abutment with zinc phosphate or glassionomer.

10- Recall every 6 months

The appliance should be constructed andfitted as soon as possible afterextraction.


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Band and Loop space maintainer


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Construction

0.7 mm wire


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Modifications of band and loop

Bonded spacemaintainer

Construction:Contoured wire bonded with composite.Disadvantage:

1. Breaks easily due to shear forces of occlusion2. Very difficult to adjust


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Modifications of band and loop

Crown and loop appliance

Disadvantage:Failure of the solder and wire break cannot be repaired intra-

orally and necessitates new crown.Alternative :If the abutment tooth requires stainless steel crown it ispreferred to adjust a band and loop space maintainer that fitsthe crown.


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Variations of band and loop


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Distal shoe space maintainer

If the second primary molar is lost beforeeruption of the first permanent molar.

The space maintainer to be used shouldguide the first permanent molar into itsnormal position such as crown or bandmaintainer with distal shoe extension or

intragingival extension. The first primary molar distal to the space is

used as the abutment tooth.


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Contruction

1- Select a band.

2- An alginate impression is taken.

3- If the second primary molar is planned for extractionbut has not yet been removed, it should be cut offthe prepared model. A hole that simulates theposition of the position of the distal root of theextracted tooth is drilled in the model.

4- If the second primary molar has been removedpreviously, the position of the tissue extension maybe determined with dividers and a bite-wingradiograph.


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5- The tissue bearing loop is contoured with awire extending distally then downwards into

the prepared opening on the model (forminga v-shaped extension). The free ends of theloop are soldered to the band.

6- The band and loop appliance is removed

from the model and the v of the tissueextension is filled in and soldered with piecesof gold.


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7- If the second primary molar has previously beenextracted and the extraction site has healed, a knifeedge is formed at the apex of the V-shaped extensionso that it can be forced through the anesthetized

area of the ridge.

8- If it is delivered at the time of extraction, the intra-gingival extension is just polished but not sharpened.

9- Before cementation of the maintainer, a radiograph

of the appliance should be taken to determinewhether the tissue extension is in proper relationshipwith the un-erupted first permanent molar.


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If the first permanent molar un-eruptedDistal shoe space maintainer


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Disadvantages of distal shoe

Cantilever design therefore fragile

Does not restore occlusal function

Complete epithelialization does notoccur so contra-indicated in medicallycompromised children.


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Lingual arch

It is a bilateral fixed space maintainerindicated in case of multiple teeth loss.

Constructed if the lower permanent incisorsare erupted. In case of presence of primaryincisors a bilateral band and loop is indicated.

Maxillary lingual arch can be used in the

primary dentition.


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There are two types of lingual arch:

Nance

Transpalatal arch


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Transpalatal arch

Bands are adapted to the maxillary firstpermanent molar and wire traverses the

palate without touching it will besoldered to the bands.

Hygenic

Can allow mesial tipping of abutment


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Transpalatal arch


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Nance appliance


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Removable appliances

Removable partial denture:

Indicated in case more than one tooth are

lost. Stainless steel wire clasps are difficult to

contour for the canines as they do not havelarge undercut.

Stainless steel wire rests for the molars onthe opposite side aid in retention.

Needs compliance thus recommended only in

case of cooperative children.


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Advantages:

It can be easily adjusted to allow for the eruption of teeth.

It restores normal masticatory function and esthetics.

Prevents abnormal speech and tongue habits.Disadvantages:

It is easily broken from a child.

If the appliance is removed from the mouth even for few days,changes in the denture base will occur and drifting of teeth

may make it impossible for the child to replace the applianceunless extensive adjustment has to be done by the dentist.

There is a possibility of the development of new cariouslesions unless proper cleaning of the teeth and denture isperformed.


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Space maintenance for multipleloss of posterior mandibular teeth


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Modified fixed partial denture


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(Pinkham, Ch. 25 page 423-430)

Space Maintainer Primary Dentition Final

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