Space maintenance can be defined as the measures or procedures that are undertaken to prevent loss of arch length. It is concerned only with the control of space loss, without taking into consideration the measures to supervise the development of dentition.
Space maintainers include appliances that are used to prevent space loss and guide the unerupted permanent tooth into correct position in the dental arch.
Causes of space loss
- Premature loss of primary tooth.
- Proximal caries.
- Loss of permanent tooth (trauma, avulsion).
- Ectopic eruption of permanent tooth.
- Dental abnormalities resulting in small-size tooth. eg. peg-lateral.
Objectives of space maintenance
These include preservation of:
- Primary space (primate spaces).
- Arch form and integrity.
- Normal occlusion (occlusal plane).
- Phonetics and aesthetics (in case of anterior space management).
Ideal Requirements
The space maintainers should meet the following criteria:
- Maintain the desired mesiodistal width (dimension) of the space.
- Not interfere with the vertical eruption of the adjacent tooth and the succedaneous permanent teeth.
- Maintain functional or physiological movement of individual teeth.
- Provide mesiodistal space opening (regaining) when it is required.
- Easy to use and easily adjustable.
- Durable and corrosion resistant.
- Easy to clean and cost-effective.
Factors to be considered
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Time elapsed since tooth loss or extraction: Maximum space loss occurs within 2 weeks to 6 months of the premature loss of deciduous tooth.
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Dental age of the patient
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Amount of the bone covering the developing permanent tooth: The developing premolars usually require 3-5 months to move through 1 mm of covering alveolar bone as observed on bitewing radiograph.
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Stage of root formation of the succedaneous permanent tooth: The developing tooth buds begins to erupt actively if the root is three-fourth formed.
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Status of the developing and erupting adjacent teeth
- Premature loss of deciduous second molar: If the erupting 2nd permanent molar is at a level higher than the 2nd premolar, then, there are chances of permanent 1st molar to tip mesially and impact the eruption of 2nd premolar.
- Premature loss of deciduous first molar and erupting lateral incisor: Lateral incisor tends to ditch the deciduous canine distally, thus, affecting the eruption of 1st premolar. This also leads to lingual inclination of the anterior teeth (particularly in the mandible), leading to collapse of the anterior segment.
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Congenitally missing teeth: If a permanent tooth is found missing before the tooth distal to it erupts, it is advisable to extract its precursor deciduous tooth. This would permit the distal tooth to move mesially and erupt in its place.
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Eruption of opposite permanent tooth: If the permanent tooth in the opposing arch has erupted, then an occlusal stop should be placed on the planned space maintainer so as to prevent the supra-eruption of the opposing permanent tooth. This in turn would maintain an acceptable Curve of Spee.
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Potential of space loss
- Loss of space is more in the maxillary arch than mandibular arch.
- Loss of space is more in a crowded arch than in a well-spaced arch.
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Patient's oral hygiene and status of dental health.
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Caries susceptibility and food habits.
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Parent's and child's attitude towards dental treatment.
Indications
- Space maintenance is appropriate only when adequate space is available, and all the unerupted teeth are present and at the normal stage of development.
- If the space after premature loss of deciduous tooth shows signs of closing.
- If the use of space maintainer will aid in or reduce the future orthodontic treatment need.
Space maintenance is not required or inadequate in case where,
- The permanent successor will erupt within 6 months (i.e, if more than one-half to two-thirds of its root has formed).
- There is not enough space for the permanent tooth or if it is missing.
- Radiographic evidence of formation or calcification of half or two-third of the succedaneous tooth root.
- The space left by the prematurely lost primary tooth is greater than the space needed for permanent successor.
- No bone is observed radiographically overlying the erupting permanent tooth, suggesting sooner eruption of tooth.
- Reduction of tooth units aid orthodontic treatment may lead to a more acceptable occlusion.
- May or may not be needed if second premolars (succedaneous teeth)are congenitally absent.
Types of Space Maintainers
Space maintainers can be classified as removable or fixed, cast partial or wrought metal, passive or active and functional or non-functional.
Removable Type
Advantages
- Easy to use and can be used in combination with other preventive procedures.
- Maintains or restores the vertical dimensions.
- Can be removed occasionally to allow blood circulation to the soft tissues.
- Serves other important functions like aesthetics, phonetics and mastication.
- Helps restricting aberrant tongue habit.
- Band construction is not necessary.
Disadvantages
- Can be lost or broken by the patient.
- Poor compliance : Patient may not wear it.
- Local jaw growth may be restricted, if clasps are incorporated.
Fixed Type
Includes Band and loop, Lingual arch, Transpalatal arch, Nance palatal arch, Distal shoe space maintainers, Prefabricated space maintainer (3D), Bonded space maintainer.
Advantages
- Can be given in uncooperative patients.
- Does not interfere with passive eruption of abutment.
- Jaw growth is not hampered.
- Succedaneous permanent teeth are guided well.
- Masticatory function is restored if pontics are placed.
Disadvantages
- Elaborate instrumentation and expert skills required.
- Decalcification of tooth may occur under the bands.
- Torque forces on abutment tooth can result in appliance breakage.
- Supra-eruption of opposite tooth, if pontics are not used.
Points to Note
- These appliances are at risk for breakage and loss, they must be monitored carefully, probably at 3-6 months intervals, to be successful.
- Patient compliance is a major problem, as in most cases, patients do not come back for space maintainers post-extraction despite being informed of the same. Therefore, it is recommended to fabricate the space maintainer before the extraction and inserted at the time of extraction.
References
- Textbook of Orthodontics (2nd Edition), Gurkeerat Singh, Jaypee Brothers Medical Publishers (P) Ltd.
- Orthodontics Diagnosis and Management of Malocclusion and Dentofacial Deformities (3rd edition), Om Prakash Kharbanda, Elsevier India (2020).
- Contemporary Orthodontics, Proffit, William R, Elsevier Mosby (2018).
*This article is an excerpt from the above mentioned books and Medical Sutras does not make any ownership or affiliation claims.