SPACE MAINTAINERS

Definition:-

According to American academy of pediatric dentistry "space maintainers are appliances made of metal or plastic that are custom fit to your child's mouth. They are small & unobtrusive in appearance. Most children easily adjust to them after the first few days.

Space Maintainers can be defined as appliances used to maintain space or regain minor amounts of space lost, So as to guide the unerupted tooth into a proper position in the arch.

SPACE MAINTAINENCE

Space maintenance can be defined as the provision of an appliance (active or passive) which is concerned only with the control of space loss without taking into consideration, measures to supervise the develop0ment of dentition.

OBJECTIVES

The objectives of space maintenance are:

Preservation of primate spacePreservation of integrity of the dental archesPreservation of normal occlusal planeIn case of anterior space maintenance, it should aid in esthetics & phonetics.

Classification of space maintainers

According to

Hitchcock (1973)

According to

Raymond C. Thurow (1978)

According to

Hinrichsen (1962)

v     Removable or fixed or semi fixed

v     With bands or without bands

v     Functional or non functional

v     Active or Passive

v     Certain combination of above

v     Removable

v     Complete arch – Lingual arch & Extra Oral anchorage

v     Individual tooth

v     Fixed space Maintainers

Class I

non functional types – Bar type,

- loop type

Functional types –                                 - Pontic type.

- Lingual arch type

Class II

Cantilever type

- Distal shoe

- Band & loop

v     Removable space Maintainers

- Acrylic Partial denture.

Ideal requirements

The space maintainers used should meet the following conditions –

v     Maintain the desired mesiodistal dimension of the space created by lost tooth (intra – arch space maintenance).

v     Should not interfere with the vertical eruption of the  adjacent teeth (inter arch space maintenance).

v     Should not interfere with the eruption of the permanent teeth.

v     Provide mesiodistal space opening when it is required.

v     Maintain individual function movement of teeth.

Factors governing the selection of Appliance

v     Patient cooperation : With removable appliances, greater cooperation is required as compared to the fixed appliance.

v     Appliance integrity : In general all types of appliance suffer breakage, But as per Wright and Kennedy the mandibular removable appliance is the most susceptible to breakage and that the integrity of Fixed appliances is better.

v      Maintenance: The length of time and the projected maintenance should be considered.

v     Modifiability: Anticipation of future modification is essential.

v     Limitation:  Loss of the 1st primary molar before eruption of the second premolar while using the band & loop.

v     Cost:  Directly bonded are the best as time is saved. As laboratory time increases, labour charge increases.

Indications

Closure of space following premature loss of second deciduous molar

If the space after premature loss of deciduous

teeth shows signs of closing.

If the need for treatment of malocclusion

at a later stage is not indicated.

When the space for a permanent tooth should be

maintained for two years or longer.

To avoid supra - eruption of a tooth from the

opposing arch.

To improve the physiology of a child's

masticatory system and restore dental health

optimally.

Contraindications

If the radiograph of extraction region shows that the succedaneous tooth will erupt soon. If the radiograph of extraction region shows one third of the root of succedaneous tooth is already calcified. When the space left by prematurely lost primary tooth is greater than the space needed for the permanent successor as indicated radiographically. If the space shows no signs of closing. When succedaneous tooth is absent.

Planning for space maintenance.

The following factors should be considered when space maintainer is planned following the early loss of primary teeth.

Time elapsed since loss of tooth. It is usually advisable to place a space maintainer as soon as the primary teeth are removed. Studies indicate that the maximum loss of space occurs within 6 months of extraction of the teeth. It would be a good idea to fabricate the appliance prior to extraction of the primary tooth and insert the appliance soon after the extraction. Dental age of the patient: the dental age of the patient should always be considered rather than the chronological age. This is because too much variation in eruption of teeth is observed. It is usually observed that the permanent teeth erupt once 3/4th of their root development is complete. The criteria can be used to predict the age of eruption of the permanent teeth.  Early loss of teeth can cause a delay in eruption of the successor. For example early loss of the deciduous molars before 7 years of age results in a delay in eruption of the premolar. Thickness of bone covering the unerupted teeth. The more the bone covering the unerupted tooth, the more would be the time it would take to erupt and therefore space maintenance is indicated. Normally premolars take 4 – 5 months to erupt through a bone of 1 mm. Sequences of eruption of teeth: whenever a space maintainer is planned, adequate consideration should be given to the adjacent developing and erupting teeth. For example when the deciduous second molar is lost early & second molar is ahead of the second premolar in its eruption, it is likely to exert a mesial force on the first molar which can move mesially. This may result in insufficient space for the second premolar. Congenital absence of permanent tooth: if permanent teeth are congenitally missing, the dentist should decide if he is going to retain the space until a replacement can be given or allow the other erupting teeth to drift and close the space. Delayed eruption of permanent tooth: individual permanent teeth are after observed to be delayed in their development and consequently in their eruption. In cases of this type it is generally necessary to extract the primary tooth, construct a space maintainer & allow the permanent tooth to erupt and assume its normal position. If the permanent teeth in the same area of the opposing dentition have erupted, it is advisable to incorporate on occlusal "stop" in the appliance to prevent supraeruption.

Presentation to parents: an important aspect of space maintenance is presenting the problems to the parents. Take sufficient time to explain existing conditions, discuss the possibility of a future malocclusion occurring if steps are not taken to maintain the space.

Removable space maintainers

Definition:- They are space maintainers which can be removed and reinserted into the oral cavity by the patient.

Classification:-

Functional space maintainers: incorporate teeth to aid in mastication, speech and esthetics. Non-functional space maintainers: have only an acrylic extention over the edentulous area to prevent space closure.

Advantages:-

They are easy to clean and permit maintainance of proper oral hygiene. They can be worn part time allowing circulation of the blood to the soft tissue. Dental check – up for caries detection can be undertaken easily. They stimulate eruption of permanent teeth. Band construction is not necessary.

Disadvantages:

They may be lost or broken by the patient. Uncooperative patients may not wear the appliance. Lateral jaw growth may be restricted, if clasps are incoperated.

Indication

Indicated when esthetic is of importance. In case of abutment teeth cannot support a fixed appliance. In case the radiograph reveals that the unerupted permanent tooth is not going to erupt in less than five months time. If the permanent teeth have not fully erupted it may be difficult to adapt bands. Thus it is advisible to use removable space maintainer.

Contraindication

Lack of patient co-operation. In patients who are allergic to acrylic materials. Epileptic patients who have uncontrolled seizures.

Some commonly used removable space maintainers

Acrylic Partial Dentures:

Bilateral removable functional passive space maintainer

Bilateral removable non-functional

Space maintainer

·          Used successfully in patients who have undergone multiple extractions.

·          The inclusion of artificial teeth in the denture restores masticatory function.

·          Clasp can be fabricated on deciduous canines & molars for retention.

Full or complete dentures:

·          In primary teeth of a pre school child where extraction is indicated for rampant Caries.

·          These denture restore masticatory function and esthetics.

·          Guide the first permanent molars into their correct position. The posterior border of the denture should be placed over the area approximating the mesial surface of the unerupted first permanent molar.

·          Denture will have to be adjusted and a portion of it cut away as the permanent incisor erupt.

Removable Distal shoe space maintainer:

·          An 'immediate' acrylic partial denture with an acrylic distal shoe extension has been used successfully to guide the 1st permanent molar into position when the deciduous second molar is lost shortly before the eruption of the first permanent molar.

·          The tooth to be extracted is cut away from the stone model and a depression is cut into the stone model to allow the fabrication of the acrylic extension.

FIXED SPACE MAINTAINERS

Definition – Space maintainers which are fixed or fitted onto the teeth are called fixed space maintainers.

Component –

Band Loop/archwire Solder joint Auxiliaries

Advantages

·          Bands and crown are used which require minimum or no tooth preparation.

·          They do not interfere with passive eruption of abutment teeth.

·          Jaw growth is not hampered.

·          The succedaneous permanent teeth are free to erupt into the oral cavity.

·          They can be used in uncooperative patients.

Disadvantages;

Elaborates instrumentation with expert skill is needed. They may result in decalcification of tooth material under the bands. If pontics are used it can interfere with vertical eruption of the abutment tooth.

COMMONLY USED SPACE MAINTAINERS

·          BAND AND LOOP

·          LINGUAL ARCH HOLDING DEVICE

·          NANCE'S PALATAL HOLDING DEVICE

·          TRANSPALATAL ARCH

·          DISTAL SHOE

·          CROWN AND LOOP

·          BAND AND BAR

Space maintenance  in the primary dentition

MISSING

SUGGESTED TREATMENT

REASON

Maxillary incisor

No space maintenance required but can be given for esthetic & phonetic purpose.

No consequence. Except  if incisor (s) is / are lost prior to primary canine eruption, space closure may be observed

Maxillary canine

Maxillary first molar

Band and loop space maintainer.

Band / crown and loop space maintainer.

Decrease possibility of midline shift.

Prevents loss of arch dimension.

Maxillary second molar

Distal shoe space maintainer.

1- Guides first permanent molar in to proper position

2- Prevents loss in arch dimension.

Mandibular canine

Band and loop space maintainer.

Decreases possibility of midline shift.

Mandibular first molar

Mandibular second molar

Band / crown loop space maintainer.

Distal shoe space maintainer.

Prevents loss of arch dimension.

1- Guides first permanent molar into proper position

2- Prevents loss in arch dimension.

Space maintenance in the mixed dentition

MISSING PRIMARY

SUGGESTED TREATMENT

REASON

Maxillary lateral incisor

Maxillary canine

Maxillary first molar

Maxillary second molar

Mandibular lateral incisor

Extract antimere

Prior to eruption of permanent lateral incisor removable space maintainer

After eruption of permanent lateral incisor extract antimere

Prior to eruption of permanent lateral incisor band / crown loop space maintainer

After eruption of permanent lateral incisor band / crown loop space maintainer

Nance appliance

Extract antimere

Decrease possibility of midline Shift

1- Guides permanent lateral incisor proper position

2- Decrease possibility of midline Shift

1- Require only minor adjustment to afford normal positioning of permanent incisor

2- Prevents loss in arch dimension

Prevents loss in arch dimension

Decreases possibility of midline Shift

MISSING PRIMARY

SUGGESTED TREATMENT

REASON

Mandibular canine

Mandibular first molar

Mandibular second molar

Prior to eruption of permanent lateral incisor removable space maintainer

After eruption of permanent

lateral incisor lingual arch space maintainer

Prior to eruption of permanent lateral incisor band / crown loop space maintainer

After eruption of permanent lateral incisor lingual arch space maintainer

Prior to eruption of permanent lateral incisor band / crown loop space maintainer

After eruption of permanent lateral incisor lingual arch space maintainer

1- Requires on by minor adjustment to afford normal positioning of permanent incisor

2- Decreases possibility of midline Shift

1- Decreases possibility of midline Shift

2- Prevents lingual tipping of permanent incisors.

1- Does not interfere with eruption of permanent incisors

2- Prevents loss in arch dimension

1. prevents loss in arch dimension

2- Permits distolateral repositioning of primary canine

1- Prevents loss in arch dimension

2- Does not interfere with eruption of permanent incisors

1- Prevents mesial tipping of  1st permanent molar

2- Prevents loss in arch dimension

EXAMPLES OF EIXED SPACE MAINTAINER

1-Band And Loop –

(Unilateral , fixed , nonfunctional , passive space maintainer)

Band and Loop space maintainer.

Indication -

Premature loss of any primary first molar.Where the unerupted premolar is more than 2 years from clinical eruption and root length is less than ½.It is also indicated when second primary molar is lost after the eruption of first permanent molar.

Contraindication –

Extreme crowding or space loss.High caries activity.

Construction -

The larger tooth, the second deciduous molar is used for anchorage of the appliance. A loop is soldered to the band and spans the edentulous space to contact the abutment tooth below the contact point.

The loop is contoured to rest on the tissue on both sides of the ridge, with an opening in the loop sufficient to permit the eruption of the cusp of the underlying  permanent tooth. The loop should contact the mesial abutment at the contact point. If it is constructed below it, the chances of it slipping gingivally are high.

Modification -

The loop can be made only on one side but it is less stable.   Sometimes occlusal rest is given on the tooth. This modification is to overcome the disadvantages of the appliance slipping gingivally. But this may hamper the proper eruption of the tooth to its occlusal plane.Crown loop: Where abutment requires a crown this appliance may be used. Two techniques can be used –

·          Where loop is welded to the crown.

·          Where the band is adapted over the crown and the loop is soldered to it.

Crown and loop space maintainer

Reverse it Bonding the first primary molar for guidance. This appliance has been used in cases where the second molar is lost before the eruption of the first permanent molar.

Reverse crown and loop space maintainer on the right lower quadrant

A cast crown with a tube on the canine and a cast crown with a bar & post can be cemented on the molar such that the post fits the tube. Techniques for constructing a functional variant of  space maintainer , either by direct or indirect technique.

Disadvantage-

Seldom used for space loss of more than one tooth.Nonfunctional Migration of the loop gingivally.Loss of E before eruption of 4.

2- Lingual arch space maintainer –

( Nonfunctional , passive mandibular arch appliance)

Lingual arch space maintainer

Indication –

Bilateral loss of posterior teeth.Minor movement of the anterior teeth.Maintenance of leeway space.Space regaining.

Contraindication –

Before the eruption of the mandibular incisor.

Introduction –

They not only control anteroposterior movements but also are capable of controlling and preventing an arch perimeter distortion.

Construction –

The lingual arch consists of a round stainless steel wire closely adapted to the lingual surfaces of teeth and anchored to bands on the first permanent molars. Rarely second deciduous molar may also be used.

Modification-

Lingual arch space  maintainer with 'U' loop Lingual arch space maintainer with canine spurs.

Fixed lingual arch space maintainer with banded first permanent molars

Pre-formed lingual arches

Disadvantages –

Loss of cementation and solder are most commonly associated with this appliance.  May cause unwanted movement.

3- Distal shoe space maintainer –

(Intra – alveolar , eruption guidance appliance )

The fixed distal shoe space maintainer was first reported by willets. The appliance is constructed when there is a premature loss of the second primary molar , prior to the eruption of the first permanent molar.

Distal shoe space maintainer

Classification –

(i). Functional –

Advantage – durable , maintains occlusion , can be used after removal of  extension.

Disadvantage – costly , time consuming , difficult construction and adjustment.

(ii). Non-functional –

Advantage – easy fabrication , low cost and single abutment.

Disadvantage – more breakage chance , less  retentive and new appliance required after eruption of tooth.

Intra-alveolar extension of distal shoe space maintainer

Distal shoe space maintainer.

Indication –

1-      Early loss or removal of the second primary molar prior to the eruption of the first  permanent molar is the prime indication.

Contraindication –

Inadequate abutments due to multiple loss.Poor patient / parent co-operation.Congenitally missing first molar.Medical conditions such as blood dyscrasias , CHD , Rh. Fever , diabetes or generalized debilitation.

Disadvantage –

Over extension causes injury to the permanent tooth bud i.e. second premolar.If under extended it may allow the molar to tip into the space or over the band.Prevents complete epithelization of the extraction socket.Ronnermann and Thialander have discussed  the path of eruption and stated that the drifting takes place only after eruption through the bony covering.

4- Nance arch or Nance space holding appliance –

( Fixed, Nonfunctional, passive maxillary arch appliance ) Nance described "PREVENTIVE LINGUAL WIRE".

It consist of bands on the upper molar with the arch wise extending forward into the vault.

Nance palatal arch space maintainer with U' loop                                 Nance palatal holding arch

Indication –

Bilateral loss of the deciduous molars.Combined with a habit breaking appliance.

Contraindication –

Palatal lesions  If either of the molars has not erupted.

Construction –

·          The acrylic button is present on the slope of the palate and provides on excellent resistance against forward movement.

·          The wire should extend from the lingual of bond to the deepest and most anterior point in the middle of third palate .

·          U band is given in the wire for the retentive of the acrylic 1-2 mm away from the soft times.

Disadvantage –

May cause tissue hyperplasia and infection due to poor oral hygiene.

5- Transpalatal arch –

( Fixed, Nonfunctional , passive appliance)

Transpalatal Arch

Indication –

Best in case where unilateral loss of space is seen.

Contraindication –

Bilateral loss.It is used in the maxillary arch. The arch is soldered to both sides , straight without a button and without touching the palate. The basis of the appliance is that migration & rotation is caused by rotation around the lingual root.  By preventing this space loss is prevented by the appliance.

Disadvantage –

May cause both the molars to tip together.

6- Crown and loop space maintainer –

It is similar to the bond and loop space maintainer in all respect except that stainless steel crown is used for the abutment tooth.

Space maintained for missing primary

first molars using the crown and loop

on left side, band and loop on the right

Indication –

The crown is used in preference to the band when the abutment tooth is –

CariousExhibit marked hyperplasiaPulpotomized

7- Band and bar space maintainer

Instead of cantilever design both the abutment teeth are bended and a bar placed in between them instead of loop. This bar may interfere with the eruption of permanent tooth.

Band and bar space maintainer