Preservation of normal occlusion and interception of malocclusion during early mixed dentition

Introduction

The objectives of preventive and interceptive orthodontics are to minimise or eliminate possible aetiological factors of malocclusion during the period of occlusion development, thereby helping in the attainment of normal occlusion.

Preventive orthodontics is the procedure done to preserve the integrity of the occlusion, which appears to be normal at that particular age during the phase of occlusion development.
Interceptive orthodontics implies the interception of a potentially developing malocclusion and/or reduction of the deformity so that the comprehensive treatment’s duration and complexity are significantly reduced or eliminated.

Goals of preventive and interceptive orthodontics

1.
Preservation of health and integrity of the primary dentition and occlusion. A healthy primary dentition will:
- a.
  Stimulate the underlying denture bases to grow normally.
- b.
  Preserve the arch length.
- c.
  Guide the eruption of permanent successors to their normal position.
2.
Prevention and interception of environmental influences on malocclusion like mouth breathing habits, non-nutritive sucking habits, abnormal muscle function and occlusal prematurities.
3.
Management of eruption anomalies during occlusion development.
4.
Preventing premature loss of primary teeth is particularly significant in the buccal segment. All deciduous teeth should be restored to normal function and mesiodistal dimensions to maintain the integrity of the arch and ‘leeway space’.
- a.
  Many cases with labial impaction of maxillary canine(s) are due to arch length deficiency caused by mesial drift of maxillary molar(s).
- b.
  An early exfoliation of deciduous first or second molars in the mandibular arch is likely to cause the erupting permanent first molar to drift forward and thereby may cause impaction of the unerupted second/first premolars and contribute to crowding in mandibular anterior segments.
5.
Early interception of deep bite, open bite, class II and class III malocclusion can reduce the burden of complicated orthodontic treatment.
6.
Improved clinical, psychological condition and aesthetic perception of the patient in frontal and lateral view.
7.
Reduction of overjet to minimise traumatic dental injuries to maxillary anterior teeth.

Management and preservation of arch length: Maintenance of space

Management and preservation of space in the mixed dentition require a thorough understanding of the child’s behaviour and the parents’ awareness and attitude. A child’s requirement to undergo dental treatment for space management is governed by several considerations like caries susceptibility, food habits, oral hygiene, social and economic status of parents, attitude and awareness of the family/parents towards orthodontic/dental treatment, access to dental care and above all the benefits expected out of treatment vis-à-vis inputs required in managing the space.

The provision of a space maintainer necessitates a thorough analysis of the case, especially with respect to the development and root formation of the unerupted teeth. For instance, space maintenance may or may not be needed if second premolars are congenitally absent. A space maintainer may not be necessary even in conditions where ¹ ⁄2 to two-thirds of the root of a succedaneous tooth is formed. It is mandatory to arrive at the complete diagnosis with respect to tooth size and arch length discrepancy by means of arch length measurements, such as Nance method and analysis of the size of unerupted tooth material using an appropriate methodology.

The arch length and space requirements are quantified. The craniofacial skeletal pattern, status of occlusion and neuromuscular behaviour are factored in while planning orthodontic management of arch length.

The immediate consequences of early loss of primary maxillary first molars are primarily distal drift of deciduous canines and incisors, causing space loss of about 1 mm in the arch. The space loss is more significant during the first 6 months, and therefore, the space maintainer should be pre-fabricated prior to extraction, which can be inserted at the same time as the extraction of the deciduous molar.

Factors influencing the rate of space loss

1.
Muscular pattern: Space loss is rapid in ectomorphic children with a vertical craniofacial growth trend.
2.
Space loss is relatively slow in children with horizontal craniofacial growth trends, such as in class II division 2 type of pattern.
3.
Abnormal musculature/habits, such as non-nutritive sucking, may accentuate the rate of space loss.

Factors influencing the plan of a space maintenance

1.
Time elapsed since extraction/loss of the deciduous tooth.
2.
Age of the child and dental age.
3.
The amount of bone between the erupting permanent tooth crown and oral cavity.
4.
The eruption of neighbouring teeth.
5.
Path of the eruption of the permanent successor.
6.
Congenital absence of teeth or presence of a supernumerary tooth.
7.
Molar occlusion and facial type.
8.
Patient’s oral hygiene and status of dental health.
9.
Caries susceptibility and food habits.
10.
Parent’s and child’s attitude towards dental treatment.
11.
The amount of root formation of the succedaneous permanent tooth.

Potential benefits of space maintaining appliances

1.
Reduced prevalence or severity of:
- a.
  Crowding, ectopic eruption
- b.
  Tooth impaction
- c.
  Crossbite
- d.
  Excessive overbite and overjet
- e.
  Poor molar relationship
2.
Reduced burden of care: When instituted with care, the interceptive treatment may save considerable costs by reducing the need for future orthodontic treatment.

Disadvantages of space maintaining appliances

Space maintenance appliances need careful planning, delivery and follow-up. When not instituted with diligent care, it may lead to:

1.
Soft tissue impingement.
2.
Interference with eruption of adjacent teeth.
3.
Pain, plaque accumulation and increased susceptibility to dental caries.
4.
Undesirable tooth movement.
5.
Inhibition of alveolar growth and prevention of tooth eruption if not removed well in time.
6.
Broken, dislodged or lost appliances can cause multiple problems.

On the basis of data from 16 papers published between 1987 and 2007, which satisfied the inclusion criteria, Laing et al. reported that there is limited evidence to recommend for or against the use of space maintainers to prevent further severity of malocclusion in permanent dentition.

Space maintenance appliances

The space maintenance appliance can be passive, that is, to preserve arch length or space of the missing deciduous tooth or active, to regain and maintain the deciduous tooth space partially lost due to migration of neighbouring teeth.

Passive appliances

Band and loop space maintainer

The most commonly used space maintainer is the band and loop design, which can be fabricated on a deciduous second molar to maintain space created by premature extraction of a deciduous first molar. The band and loop can be planned and fabricated before the extraction of a deciduous tooth and cemented immediately after extraction or can be fabricated post-extraction.

A pre-fabricated band is selected for the tooth, which is most often a deciduous molar or permanent first molar. The band is left on the tooth while an alginate impression is made. The band is removed and transferred to the alginate impression at its appropriate position and orientation. A dental stone cast is poured. A wired framework is fabricated and soldered onto the band. The appliance is polished. It can be cemented immediately after extraction of the carious deciduous molar with fluoride releasing glass ionomer cement (GIC). Check for occlusion and any interferences with the teeth in the opposite arch or impingement on soft tissues ( Fig. 49.1 ).

3D printed band and loop space maintainers

Computer-aided design/computer-aided manufacturing (CAD/CAM) and 3D printing methods enable precise fabrication of space maintainers in a single piece, eliminating issues like solder breakage and appliance failures. Challenges like band pinching and transferring bands during impressions are eliminated in paediatric patients. 3D printing reduces human errors and simplifies laboratory procedures, shortening fabrication times and reducing the number of appointments needed. Unlike traditional methods, 3D printed space maintainers distribute occlusal stresses differently due to their single-unit design without solder joints, ensuring better adaptation and occlusion even under high forces. Furthermore, digital workflows streamline impression-taking from children and prevent data distortion during transfer to laboratories ( Figs 49.2 and 49.3 ).

On evaluating the efficacy of 3D printed band and loop space maintainer and conventional space maintainer, 3D printed SM showed higher clinical success and patient comfort compared to traditional SM; however, both the groups noted increased gingival inflammation and the need for good oral hygiene maintenance.

In a comparative evaluation between conventional band and loop space maintainer and 3D p rinted space maintainer for clinical success and oral hygiene maintenance, both the appliances showed clinical failures (traditional 38%, 3D printed 66%) and increased gingival index, thus emphasising the importance of oral hygiene maintenance irrespective of the type of space maintainer used.

The facilities for 3D printed metal space maintainers are limited and involve high cost.

Removable partial denture

A removable partial denture can be fabricated in situations of multiple extractions, such as in maxillary dentition, which also serves as a space maintainer ( Fig. 49.4 ).

Distal shoe space maintainer

The appliance is indicated for guiding the unerupted permanent first molar into the position after the premature loss of or extraction of the second primary molar. This can be prepared with the molar band as the technique described above or as a single sitting appliance with a stainless steel crown as a retainer. A stainless steel crown is fitted on the primary molar. A stainless steel extension is soldered to the crown and extended to the former distal contact of the primary second molar to guide the eruption of the first molar ( Fig. 49.5 ). After the first molar erupts in the mouth, distal shoe space maintainer is replaced with a more stable space maintainer like band and loop maintainer.

Bonded space maintainer

The successful advent of bonding on tooth surfaces has also been inducted in paediatric dentistry in the maintenance of space. A rigid wire framework can be bonded between the lower first molar and the deciduous lower molar.

Others have used glass fibre reinforced composite resin space maintainers. The space maintainer is prepared on the chair side and fixed with adhesive bonding. It is easy to fabricate, does not require impression and band making and is aesthetic. ^,

Lower lingual arch (LLA)

LLA is an excellent space maintainer where multiple deciduous teeth are to be extracted due to dental caries. LLA can be a passive arch to maintain the arch length or can be activated to upright mesially tipped mandibular first molars to some extent ( Fig. 49.6 ).

LLA can also be used when a unilateral primary canine is lost prematurely, disrupting the integrity of the arch and causing a shift in the midline. In such cases, the contralateral deciduous canine may be extracted, and a LLA is cemented. The purpose of LLA here is to prevent lingual tipping of permanent incisors and, hence, loss of arch length.

The LLA is made of 0.036-in. stainless steel wire. It can be a fixed lingual arch, which is soldered to the lingual side of molar bands or a removable one, which can be inserted and removed by the dentist. The removable lingual arch has a male and female assembly and a lock. The lingual vertical tube (female) is welded onto the molar bands, while the vertical inserts (male) are prepared by bending a closed vertical loop in the lingual arch. An arch can be used to regain small spaces and upright mesially tilted mandibular molars. The LLA can be retained in the mouth till the eruption and settling of premolar buccal occlusion. Thereafter, the LLA can continue to serve the purpose of anchorage enhancer should there be a need for a comprehensive phase of orthodontic treatment. Therefore, molar bands should always carry buccal tubes.

In a systematic review conducted to evaluate the effectiveness of lingual arch in controlling the mandibular molars and incisors in the vertical direction, LLA was found to be an effective passive space maintainer.

Nance button as a space maintainer

In the maxillary arch, a Nance button arch cemented on the first molars serves a valuable purpose to prevent mesial migration of the first molars when multiple deciduous teeth have been extracted.

Digitainers: Digital space maintainers

Space maintainers incorporating CAD-CAM or 3D printing technology, using modern biocompatible materials, are referred to as ‘Digital Space Maintainers’. These can be manufactured from materials such as PEEK (polyetheretherketone), BruxZir (high-quality zirconia material for crowns) and Trilor (A fiber-reinforced composite material). The fabrication process involves digitising the dental model with an intraoral scanner, creating a virtual model, designing the appliance using specialised software, and finally, 3D printing the appliance ( Fig. 49.7 ).

The advantages of employing 3D technology for space maintainers include the production of aesthetic, metal-free appliances that are rigid, smooth, lightweight and precisely tailored to the patient’s anatomy. However, this method is technique-sensitive, necessitates expertise and laboratory support, and tends to be costly.

Active space maintainer or space regaining appliance

An active space maintainer would be used to regain the space lost due to tipping and migration of adjacent teeth into the extraction space(s), that is, loss of arch length. The critical factors to be considered are:

1.
Type and severity of existing malocclusion.
2.
Radiographic evidence of the presence of the permanent successor for which space is being regained, its space requirements for accommodation in the dental arch and dental age vis-à-vis eruption status.

A space regainer appliance is fabricated with the sole objective of either uprighting a mesially tipped mandibular molar or distalising a maxillary first molar; however, the mechanics involved can be quite intricate. A space regaining procedure should be attempted following complete space analysis and thorough diagnosis with regard to future comprehensive orthodontic treatment based on the nature of malocclusion, craniofacial skeletal pattern and remaining growth. A space regaining procedure could be the initial step towards more comprehensive treatment procedures that may follow or be required at a later date.

A sectional fixed appliance with an open coil spring compressed between brackets of the first premolar and molar tube is used to create space for the erupting second premolar. This is the most common space-regaining appliance ( Fig. 49.8 ).

Mandibular arch

Sectional or full fixed appliances can be used to regain lost arch length with various modalities which are described in the later chapters in the book.

Lip bumper can help upright the mesially tipped lower molar(s) and regain lost space.

A sectional expansion screw serves the same function as a sectional fixed appliance.

Maxillary arch

Sectional or full fixed appliances can be used to regain lost arch length with various modalities which are described in the later chapters in the book.

Maxillary molar distalisation is a part of comprehensive orthodontic therapy and may constitute interception of malocclusion in the mixed dentition stage when attempted to regain space lost due to the mesial migration of the maxillary molar associated with early loss of deciduous molar. These methods have been described in great detail in Chapter 60 on non-extraction treatment. Space maintainer protocols and options for the teeth in primary and mixed dentition are represented in Figs 49.9 and 49.10 .

The efficiency of space maintainers and space regainers in mixed dentition was evaluated for preserving and correcting dental arch length. Nine studies on space maintainers (lower lingual arch) and two studies on space regainers (one lip bumper and one transpalatal arch) were reviewed. The findings suggest limited evidence supporting their efficiency in maintaining arch length and preventing mild to moderate crowding in children during the mixed dentition stage, potentially causing lower incisor proclination.

Serial extraction protocol

Serial extraction is an interceptive procedure, which is more appropriately termed as eruption guidance. It can be defined as an interceptive orthodontic procedure that helps to resolve tooth crowding of 8 mm or more by the serial creation of space in the arch during the development of occlusion by a system of tooth removal, which usually begins with a deciduous tooth (often deciduous canine and sometimes deciduous first molar), leading to the extraction of all first premolars.

The serial extraction procedure is a major component of the comprehensive orthodontic treatment, which lasts from the early mixed dentition stage to permanent dentition when a phase of full-banded fixed mechanotherapy of lesser duration is needed.

Historical perspective

The principle of early treatment, associated with the extraction of primary teeth followed by the removal of permanent teeth, was first described by a Frenchman, Robert Bunon, in his ‘Essay on the Diseases of the Teeth’, published in 1743, over 280 years ago! Kjellgren, a Norwegian, is credited for coining the term ‘Serial extraction’.

According to Dale, ‘the term is somewhat dangerous because it tends to create a misconception of simplicity. It is, in fact, misleading. It implies that there is nothing more involved than the mere extraction of teeth’. Hotz’s term, ‘Guidance of Eruption, or the term Guidance of Occlusion is better’. ^,

One of the major considerations for undertaking a serial extraction procedure is the prediction and assessment of growth and severity of crowding during early childhood and early mixed dentition. ‘The most crucial decision that we as specialists in orthodontics are required to make the correction of a malocclusion: should we extract teeth or not’? To add the dimension of time, to complicate it with growth and development, and to carry it out in a serial manner is even more demanding! Serial extraction is not easy, as so many mistakenly believe, and it should never be initiated without a comprehensive diagnosis! One can extract teeth with the greatest of ease during serial extraction procedures, but if the basic principles of diagnosis are ignored, the result will be failure and disappointment. It will not only be injurious to the patient, but it will also hurt the reputation of the practitioner and, ultimately, our speciality of orthodontics. ‘Serial extraction (based on a thorough knowledge, a sound diagnosis) carried out carefully and properly on a selected group of patients can be, most assuredly, a beneficial and valuable treatment procedure’.

Controversies with serial extraction

The most difficult part of the procedure is the decision to undertake the procedure. ‘Serial extraction is used much less now than a generation ago because it is hard to be certain that crowding in the early mixed dentition is severe enough to make the extraction decision at the time’. On the other hand, there is much controversy about the best way to treat class I crowding. Data show that, in moderate crowding, starting treatment just at the end of the mixed dentition and maintaining leeway space facilitates non-extraction treatment.

For a patient with crowding in the early mixed dentition, there are four possibilities:

1.
Wait until the second deciduous molars are ready to exfoliate.
2.
Intervention is required if there is early loss of the deciduous canines.
3.
Proceed with serial extraction or
4.
Expand the arches at that time.

All these approaches are practical; the question is not whether they work but whether they produce a better result that justifies the long duration, expense and burden of treatment.

Benefits and indications of serial extraction

Serial extraction or eruption guidance procedures in extremely severe crowding can reduce the duration and complexity of the comprehensive treatment. A growing child of developing malocclusion should be considered for serial extraction procedure only if non-extraction treatment modalities(s) cannot be successfully applied. It may be well visualised that extraction of first premolars in the mandibular arch entails that corresponding maxillary first premolars would need to be extracted to maintain harmony in occlusion.

Indications for serial extractions are:

1.
A child with a potential for moderate to severe crowding.
2.
A child with no abnormal craniofacial skeletal growth pattern.
3.
A child who will be available for long-term follow-up and further comprehensive orthodontic treatment.
4.
A growing child having class II malocclusion with a lower normal arch and mild crowding in the maxilla or dentoalveolar protrusion can be treated with extraction of upper first premolars alone, thereby leaving maxillary molars in the class II relationship.

The most appropriate indication of serial extraction is a child who is in the early mixed dentition stage, has a large tooth size-jaw size discrepancy and has a class I skeletal base. Such children are characterised by blocked out malposed incisors; there is usually a premature loss of deciduous canine on one side and possibly a midline shift. Serial extraction can be a choice in select class II cases. However, it should be contraindicated in the majority of class III and class II cases, especially those with a tendency for a deep bite.

Class II division 2 malocclusion

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Tags: Kharbanda's Orthodontics: Diagnosis and Management of Malocclusion and Dentofacial Deformities, OP Kharbanda

May 10, 2026 | Posted by drzezo in Orthodontics | 0 comments

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