Aim of Orthodontic assessment in a growing child is to differentiate between a developing normal occlusion and a potential malocclusion. Space management can minimize the development of crowding in permanent dentition. It essentially involves:
Maintenance of space following the premature loss of primary molars.
Early loss of primary teeth may comprise eruption of succedeneous teeth.
May lead to loss of arch length due to migration of teeth in space available.
Tooth loss can be in terms of anterior or posterior teeth:
Anterior teeth (causes ) Posterior teeth
- Trauma - Rampant caries
- Rampant caries - Congenitally missing
- Congenitally missing (Anodontia or Oligodontia)
(Anodontia or Oligodontia)
Utilization of leeway space by placement of holding arches (Ex: lingual holding arch or Transpalatal arch).
- Combined mesiodistal width of C,D,E is more than 3,4,5 which can be utilized to relieve mild crowding (1-2mm) elsewhere in arch.
I. Clinical assessment for space management:
It can be carried out according to guidelines laid down by AAPD (American Academy of Pediatric Dentistry):
Intra-oral Examination to :
Assess overall oral health status.
Determine status of patients occlusion
Crowding/ Spacing in U/ L arch
Over jet/ Overbite/ Molar relationship
Anterior and posterior cross bite
Determine asymmetric growth patterns and lateral deviations of mandible.
Determine dental and skeletal growth.
Dental and skeletal abnormalities.
Detect TMJ dysfunction.
II. Orthodontic Assessment:
Skeletal Molar relationship.
- Supernumerary teeth
- Condition of teeth
ii. Inter-arch problems:
- Increased over jet/ overbite
- Open bite
- Cross bite
iii. Other factors:
- Oral habits
i. OPG: Gives overall picture of developing dentition.
ii. Bite-wing: For detecting proximal caries.
iv. Lateral Cephalogram: To access skeletal discrepancies, planning for treatment and baseline to monitor growth.
v. Anterior Occlusal: For location of supernumerary, ectopic and impacted teeth.
E. Mixed dentition analysis.
F. Factors which should also be taken into consideration are:
1. Space Loss:
Space within dental arch is a combination of right and left (buccal) segments plus right and left incisor segments.
- When arch length is considered only the space anterior or mesial to Ist molar is considered.
Space loss can be produced by shortening of any of these segments.
Arc of arch is decreased by mesial migration of permanent molars or with lingual inclination of incisors.
2. Molar Migration:
Eruptive or occlusal forces of Ist molars tend to drift these teeth forward, thus interproximal caries or early loss of E can lead to large amounts of space loss.
Helm reported that space closure is more common in mandible than in maxilla, whereas Ronnerman’s study showed the reverse.
Space loss according to Ronnerman and Thilander after unilateral tooth extraction is as follows:
Due to extraction of Upper D - 0.5 to 1mm
Due to extraction of Upper E – 3.7 to 4.5 mm
Due to extraction of Lower D – 0.8 to 1.7 mm
Due to extraction of Lower E – 2.1 to 3.1 mm
According to Ronnerman and Thilander if Ist molar is allowed to erupt without having guidance of E than Ist molar completely drifts bodily into the space of E in upper arch but in lower arch it only gets inclined.
Therefore clinically space loss is more in lower arch because molar space loss is severe in terms of distance i.e. in millimeters.
3. Eruption time Differences:
According to Bjork et al when E are extracted prematurely, Ist molar erupted early and same is true with incisors.
But it has been noted that early loss of deciduous canine does not affect permanent canine eruption time.
It has been found that chances of space closure are less as child ages.
This is because as the child ages the succedeneous teeth have erupted towards the alveolar crest leading to less chances of space closure.
It has been observed that eruption of premolars is retarded if the deciduous teeth is extracted prior to 7 1/2 years of age while it is hastened if extraction occurs after that age.
4. Incisor Migration:
Premature loss of primary canines particularly in mandible arch, leads to linguodistal inclination of incisors to close the space leading to midline shift, often requiring extraction of antimere tooth to prevent midline shift.
Since loss of primary canine is very rare but if it happens than from a conservative point of view a band and loop space maintenance or RPD may be placed if patient is cooperative.
Replacement of lost deciduous incisors is done for aesthetic concerns. A RPD or a fixed lingual arch can be given.
- Space closure in incisor segment is generally not seen but if occurs is due to mesiolingual inclination of adjacent teeth caused by pressure from surrounding muscular environment.
If space maintainer is not placed in maxillary anterior region, a midline shift to affected side is anticipated when permanent incisors erupt.
In mandibular arch lingual movement of incisors and midline shift will occur.
In order to prevent midline shift in mandible lingual arch can be given after permanent incisors erupt.
Factors influencing mesial/distal drift:
Degree of crowding:
Directly related to rate and extent of drift.
In uncrowded arch there may be little or no movement of teeth but in crowded arch adjacent teeth quickly move into spaces provided by extraction of teeth.
Tooth extracted :
Loss of E allows mesial drift of I permanent molars; especially if unerupted.
Extraction of C allows distal drifting of incisors but mesial drift is minimal.
Extraction of I molar allows some mesial as well as distal drifting of adjacent teeth.
Relative amount of mesial and distal drifting expected following extraction of following primary tooth is :
2nd Molar (E) +++ +
1st Molar (D) ++ ++
Canine (C) + +++
3. Age of Patient:
- Earlier the primary tooth is extracted, greater are the chances of drifting of teeth, but over eruption of opposing teeth may limit movement.
- Even in uncrowded arches, if E is extracted prior to eruption of I molar its mesial drift is inevitable specially in upper arch.
- Gron reported that permanent teeth erupt when 3/4th of the root of permanent teeth is formed.
- Studies indicate that:
Loss of D or E before 7 years – Leads to delayed eruption of permanent teeth and vice versa.
Loss at 4 years – Leads to delayed eruption of premolars by 1 year.
Loss at 6 years - Leads to delayed eruption by 6 months.
Nature and prevalence of space loss:
Following observations should be recorded before assuring prevalence of space loss:
Incidence of premature loss of deciduous molars:
Very frequently premature loss of deciduous molars cause crowding of teeth due to space loss associated with rotation, tipping or bodily movement of permanent teeth, leading to molar.
Percentage of M/O due to premature extraction of D & E.
Lyons 1924 65%
Brandhorst 1932 20%
Willets 1933 28%
Tandon 1985 50%
Rate and time of space closure:
Unger (1938) proposed that the earlier the loss of tooth, greater is the initial rate of space loss.
Seward (1965) found that in maxilla space loss is more (1.5mm) as compared to mandible (1mm) per year.
Northway (1854) reported that rate of space closure is more in first year of following extraction.
Rate of space loss in maxilla is age related:
At 6 yrs of age - 4.1 mm
At 7yrs of age - 2.1 mm
Above 7 yrs - < 1.5 mm
- In mandible the age relation was not observed. Average loss was from 2.6 to 3.2 mm in 4 years.
Amount of space closure:
Maximum space loss is seen in maxillary region due to premature loss of E.
Direction of space loss:
Earlier studies revealed that space closure:
In maxilla - Due to mesial migration of posterior teeth.
In mandible -_Due to distal migration of anterior teeth.
Explanation was based on Kronfeld’s theory that neutral areas are located in bicuspid region in maxilla and mesial to I molar in mandible, therefore teeth anterior to neutral area drift distally while posterior one shift mesially.
Northway et al in 1984 stated that for both arches, greatest space loss occurred due to mesial migration of I molar.
Effect of Caries:
Due to caries 1mm of space loss is seen in both arches.
Consequences of Individual tooth Loss:
Maxillary D loss:
Primary canine shows distal drift in 1st year of life.
E and 6 shift mesially depending upon age and duration of absence.
Permanent canine has no space and is blocked out of arch.
Maxillary E loss:
- I molar shifts mesially resulting in permanent space loss, more in upper than in lower arch.
Cuspids and D shift distally.
Ist PM generally erupts first and erupt into the space of E leading to impaction of II PM.
Mandibular tooth loss: (Effects are similar as in loss of D, E or D&E)
I molar tips mesially, in case of loss of E.
If D is lost E may tip forward.
I and II PM may not erupt due to lack of eruption forces.
In severe cases II PM may also get impacted.
Anterior region :
Most studies report that loss of anterior teeth rarely are associated with space loss, specially when primary canine has already erupted.
Premature loss of canine on one side of arch in mandible is associated with midline shift in same direction.
Barber 1987, reported that there is linguo-distal inclination of anterior permanent teeth leading to collapse of arch lingually, apart from closure of space and midline shift.
Space maintainer during primary dentition is aimed primarily at replacement of primary molars. Loss of molars can lead to space closure from both the directions i.e. mesially and distally.
Space maintenance is defined as “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 development of dentition”.
Space maintainers are defined as “appliances used to maintain or regain minor amount of space lost so as to guide the unerupted tooth into a proper position in arch”.
Factors to be considered before placement of space maintainers:
Placement of SM requires care of the appliance and maintenance of oral hygiene.
Patients with high caries risk are not suitable candidates.
Loss of one or more primary incisors results in negligible space loss and if canines and molars are present – SM not required.
If eruption of permanent incisor is delayed, space loss may occur because of migration of adjacent teeth - SM is required.
When primary II molar is lost prematurely, whether before or after the eruption of I molar (permanent), there will be some loss of arch length caused by mesial drift of permanent molars - SM is required.
The earlier the loss of E and less the root development of permanent molar, greater the amount of bodily mesial shift of permanent molars.
Amount of bone present:
- If more than 1 mm of alveolar bone is present (as seen through a bite-wing radiograph), than space maintainer is required because it has been found that premolars generally take 4-5 months to erupt if 1mm of bone is present occlusally.
Classifications of Space maintainers:
I. Classified as:
Cast Partial Wrought partial Banded Bonded
- Band & loop
- Lingual arch
- Distal Shoe
- Nance palatal arch
- Transpalatal arch
According to Hitchcock:
Removable or Fixed or Semi-fixed.
With bands or without bands.
Functional or Non-functional.
Active or Passive.
Combinations of above.
III.According to Raymond C. Thurow:
b. Complete arch.
c. Individual tooth.
IV. According to Hinrichsen:
A. Fixed SM:
a. Class I:
- Non-functional type
- Bar type
- Loop type
- Functioal type (lingual arch type)
b. Class II:
- Cantilever type (distal shoe, band and loop)
B. Removable type (acrylic partial denture)
NOTE - The best space maintenance therapy is to preserve the primary molars until exfoliation.
Types of Space Maintainers:
Band and loop Space Maintainer:
Band And Loop Space Maintainer is the commonest space maintainer which is used to hold the space of one tooth.
Lengthy loop is more susceptible to forces of mastication and appliance becomes less stable therefore not recommended.
- Favorite application is in cases with unilateral loss of ‘D’.
- Bilateral loss of primary molars before eruption of permanent incisors.
- To maintain space of ‘E’ after the eruption of ‘6’.
- Some times for premature loss of ‘C’.
- Construct a band on abutment tooth, it should be 1mm below the mesial and distal marginal ridges and should not come into occlusion.
Cervical margin of the band should fit just under the gingival margin.
If the margin of the band is not sub gingival and the patients oral hygiene is not excellent, cervical caries could occur.
- Make alginate impression of band and edentulous area.
- Remove the band from tooth, position it accurately in the impression and stabilize.
- Flow the stone into the impression carefully to avoid dislodgement of the band.
- Cast is separated.
Loop is formed with 0.036” (21 gauge) wire and contoured to fit the band and alveolar ridge.
Loop should parallel the edentulous ridge 1 mm off the gingival tissue and should rest against the adjacent tooth at contact point.
Faciolingual dimension should be 8mm, this dimension should allow the permanent tooth to erupt freely but not impinge on buccal mucosa or tongue.
- Now loop is soldered.
Band and loop is cemented with ZnPO4 or GIC.
Recall every 3-4 mos.
Remove when tooth starts erupting..
Construction is simple.
It is economical.
Takes little chair side time.
Adjustment is easy to do.
- Decalcification under bands is seen.
- Does not prevent supra-eruption of opposing tooth.
- Does not restore function.
- Limited to hold single tooth space.
2 modifications are there BUT NOT recommended for SM therapy.
1. Crown & Loop :
Requires preparation of abutment tooth for a Stainless Steel Crown and then soldering wire loop directly to the crown.
This is NOT recommended because of two reasons.
First, abutment tooth has to be compromised, and
Second, adjustment is difficult and if breaks can not be soldered without removing SSC.
2. Bonded Band and Loop with composite resin:
Not recommended for 2 reasons-
First, it is difficult to keep the wire bonded to the tooth because of shear force of occlusion. If bond breaks, there is potential loss of space and danger of aspiration of the wire.
- Second, the bonded band and loop is nearly impossible to adjust.
Mandibular Lingual Arch:
- A classical mandibular arch SM consists of bands cemented on Ist molars which are joined by a SS wire butting against four incisors.
- A conventional lingual arch is attached to bands on E or 6 and contacting the cingulum of incisors preventing anterior tooth movement of posterior teeth and posterior tooth movement of anterior teeth.
- It is indicated when several primary molars are missing and permanent incisors have erupted.
Also given for single tooth loss: e.g.: when E is missing and D is in late stage of exfoliation.
Preserves deciduous canine space in case of early loss during permanent lateral incisor eruption.
- Can not be used in primary dentition in lower arch since it interferes with normal eruption of permanent incisors.
May be used distal to the anterior teeth to prevent their tipping or migration distally.
Helps in maintaining symmetry of centre line, especially in cases of unilateral tooth loss.
At times loop may be incorporated mesial to 6.
By activating the loop it may be possible to move 6 distally.
Care must be taken with this technique as it is possible for the reciprocal force to displace the incisors labially.
- Mandibular arch wires are usually 0.036 - 0.040 inch in diameter.
Smaller diameters are not indicated, as they may not be able to resist forces of mastication.
- It should rest on lingula of permanent incisors, approx. 1.0-1.5 mm off the soft tissue.
It should be stepped to the lingual in the canine region to remain away from the primary molars and erupting premolars
It should be 2 mm below the gingival margin or edentulous ridge in the posterior region to prevent distortion under the forces of mastication.
Also it should be located 1-2 mm lingual to the posterior teeth to permit satisfactory eruption of bicuspids.
- Impingement of wire on soft tissue should be avoided otherwise tissue can form over the wire and surgical procedure may be required to free the appliance.
The arch wire should meet the band at MESIOLINGUAL CUSP.
- Wire is attached to the band in 2 ways.
By soldering By locking system
(Fixed – Usual way) (Removable)
Directly soldering wire to bands has several advantages:
The area of union can be smoothly coutoured.
Patient wearing this appliance over a long period of time tend to exhibit less tissue hypertrophy, and
Becomes less sturdy hence requires less supervision.
The arch wires that employ a locking system:
Are easier to insert, since the band can be cemented individually.
Isolation from saliva is easier
Easier to modify.
Stabilization can be problematic with long term wearing,
They are more prone to breakage and loss because they use functional retention instead of solder joints.
- It is an excellent source of anchorage because it incorporates resistance of several teeth.
- Causes little or no inconvenience to the patient.
- Less bulky than removable acrylic space maintainer.
- Probably the best SM for all problems in mandibular arch.
- Decalcification under bands.
- Does not prevent supra-eruption of opposing teeth.
- Does not restore function.
- Wire may be embedded in to the soft tissue due to poor oral hygiene.
- Wire may be distorted and can move teeth into undesirable position- so regular checkup is necessary.
Maxillary Lingual Arch Wire:
Are designed to prevent mesial migration of maxillary molars.
- They are similar to mandibular LAW but are contraindicated in patients whose bite depth causes the lower incisors to contact the arch wire on lingual of the maxillary incisors.
- When bite depth does not allow use of conventional design, either the NANCE holding arch or a TRANSPALATAL ARCH can be used.
- Indications of maxillary LAW is similar to mandibular LAW.
Nance Palatal Arch:
Is simply a maxillary lingual arch that does not contact the anterior teeth but approximate anterior palate.
- It incorporates an ACRYLIC BUTTON which is placed on DESCENDING PORTION of palatal tissue (ON PALATINE RUGAE)
- Button is about 0.5 inch in diameter.
- The button is intended to distribute force over a large palatal area so that the wire does not get embedded in the tissue.
- Excellent space maintenance.
- Tissue irritation can be a problem.
Runs directly across the palatal vault, avoiding the contact with soft tissue.
When permanent maxillary molars move anteriorly they rotate mesiolingually along the large lingual root. The transpalatal arch reduces anterior molar movement by preventing this rotation.
Best indication for TPA is when one side of the arch is intact and several primary teeth are missing on the other side.
- It is not indicated when primary molars have been lost bilaterally because permanent molars may tip mesially despite the arch (In this case Nance palatal arch or maxillary lingual arch is preferred).
- Simple in construction.
- Many clinicians think that it allows the teeth to TIP MESIALLY, resulting in space loss.
Failure to adequately maintain space, and
Failure of the appliance to remain passive. If the appliance is not passive, unexpected virtual and transverse movement of permanent molars can occurs.
Distal shoe Space Maintainer (Intra-alveolar Appliance):
- Distal SM is indicated when ‘E’ is lost before eruption of 6.
- Mesial movement and migration of 6 often occurs before eruption when there is premature loss of ‘E’ – so distal shoe is given to guide the eruption of 6 in to normal position.
- Fixed distal shoe SM was first introduced by Willet (1929). This was a cast gold appliance and soon was disfavored due to cost. It has kind of gingival extension.
- Second type of fixed appliance is Roche distal Shoe (1942). Major difference between the two is intra-alveolar extension.
- Roche appliance offer ‘V’ shaped end compare to the bar type.
‘V’ shape offers a broad surface area and helps prevent rotation.
The broader surface area also holds a greater chance of success if the unerupted tooth is positioned bucally or lingually.
(Distal shoe is constructed very much like the band and loop SM).
- Band formation is done on ‘D’
- Impression is made with the band.
- Band is removed from mouth and placed into impression.
- Plaster is poured into the impression and stone model is prepared.
- If E has not been removed, it is cut off the model and hole is made in cast.
- It E has been removed previously, the position of the alveolar extension may be determined with the help of dividers and bite wing radiographs, if the corresponding E is present, the correct M-D width can be measured from it.
- Now SS wire of 0.040 inch is adapted along the ridge and into the prepared opening on the model. Free ends of the loop are soldered to the band.
- Band and loop appliances is removed from the model and ‘V’ of the tissue extension is filled in and soldered with pieces of 0.040 inch wire.
- A knife edge is formed at the apex of ‘V’ if E has been previously extracted and extraction socket has healed, since the sharpened distal shoe may be forced through the anesthetized area.
- If the appliance is delivered at the time of extraction, the intra- gingival extension is just polished but not sharpened.
- Before final placement of appliance in the mouth, a radiograph of the appliance should be made to ensure correct positioning. The depth of the intragingival extension should be about 1.0-1.5 mm below the mesial marginal ridge of 6.
- After 6 is erupted, the intragingival extension is removed if the appliance is to be used as a reverse band and loop, it may be necessary to add a supragingival extension to prevent molar tipping over the wire.
- Histological studies show that distal shoe implant never becomes lined with epithelium (i.e. complete epithelialisation does not occur) and is associated with chronic inflammatory process.
- Can not be given in medically compromised patients such as those suffering from blood dyscrasias, immunosuppression, congenital heart defect, rheumatic fever, diabetes etc.
- Poor oral hygiene and lack of patient and parent co-operation.
- Instances in with the distal shoe is contraindicated, two possibilities exist:
Allow the tooth to erupt and regain space latter.
Use a removable or fixed appliance that does not penetrate the tissue but places pressure on the ridge mesial to the unerupted 6.
Faulty positioning is the most common problem with this appliance.
Can replace only one tooth space.
Lacks sufficient strength.
It is fragile.
No occlusal function is restored.
Advantages of Fixed SM:
- It entirely eliminates the factor of patient co-operation.
- They do not hamper the growth of jaw.
- Passive eruption of abutment teeth is not interfered.
Disadvantages of Fixed SM:
- Elaborate instrumentation with expert skill is needed.
- May result in decalcification under the band.
- Does not prevent supra-eruption of opposing teeth.
Removable Acrylic Space Maintainer:
- Removable acrylic SM is typically used when more than one teeth has been lost per segment.
- Following factors encourage selection of removable appliance:
Multiple tooth loss.
Partially erupted teeth (Because fabrication of lingual or palatal arch is impossible)
For prevention of supraeruption.
Longitivity of the appliance: An unfavorable eruption sequence can reduce the period of effectiveness of band and loop appliance. It may need to be replaced by a lingual arch at a later stage. Use if a removable appliance can eliminate the need of two appliances; however modification will be needed to be made on teeth.
- Loss of more than two primary molars.
- Loss of more than one primary tooth bilaterally.
- Loss of anterior teeth.
- In high risk caries children.
- If the permanent teeth have not fully erupted, and the adaptation of band may be difficult.
- In un co- operative patient.
- Patients allergic to acrylic.
- Epileptic patients having uncontrolled seizures.
Advantages of Removable Appliances:
- They aid in esthetics, speech and mastication.
- Not only M-D space but vertical dimension is also maintained that is they prevent supra-eruption of opposing teeth.
- They permit maintenance of proper oral hygiene as they are easy to clean.
- Caries detection can easily be done in dental check up.
- Deleterious oral habits are prevented.
Disadvantages of Removable Appliances:
- Patient co-operation is desirable.
- Lateral jaw growth may be restricted if clasps are incorporated.
- They may be lost or broken by the patient.
- It may irritate the underlying tissue.
Bonded Space Maintainer:
- Wire is directly BONDED to the tooth, no BAND formation is done.
- Round, multistranded 0.032 inch wire is used.
- Wire is bonded to middle 3rd of tooth surface.
Wire can run straight from one abutment to the other.
To minimize the occlusal forces, this SM is bonded bucally on the maxillary teeth and lingually on the mandibular teeth.
This design can be modified and adapted on buccal surface of the mandibular teeth by giving a band to the level with gingival margin to decrease occlusal force.
- Band adaptation NOT required hence les time consuming.
- Needs single sitting No lab work.
- Can act as active space maintainer or space regainer.
- Lack of long term studies.
Methods of Regaining Space:
I. For Mixed Dentition:
There are 3 ways of regaining space in this period:
Method by which proximal surfaces of teeth are sliced in order to reduce M/D width of teeth.
Routinely carried out on lower anteriors and buccal segments of upper/ lower arch.
A. Arch Perimeter Analysis:
- Space discrepancy is of 0 – 2.5 mm.
B. IOPA radiographs:
- It helps in estimating thickness of enamel interproximally and helps in evaluating amount of enamel required to remove enamel.
Amount of Slicing:
Not more than half the thickness of enamel should be removed.
Reduction should be done maintaining proper contour interproximally.
Slicing can be done by using metallic abrasive strips, safe sided carborandum discs or with long thin tapered fissure burs.
Indicated when space required is minimal i.e. 0 - 2.5mm.
As an aid to retention in lower anterior region.
If Bolton’s Ratio shows mild tooth material excess in either of the arches.
Not carried out in young patients due to presence of large pulp chambers.
In patients susceptible to caries who have high caries index.
If arch discrepancy is more than 3 mm.
Avoids extraction in borderline cases.
By eliminating tooth material excess a more favorable overbite and over jet can be established.
Prevents derotation of teeth since it broadens the contact area thus eliminating chances of slippage.
Leads to roughened surfaces hence becoming more prone to plaque accumulation.
Caries susceptibility is increased.
Patient may experience sensitivity of teeth.
Skill is required since proper contour has to be maintained.
Food impaction occurs interproximally due to loss of contact.
First described by R. Bunon in 1743.
Term was coined by kjellgren.
Nance in 1940’s named it as “planned and progressive extraction”. He is called as “Father of Serial Extraction philosophy”.
According to Graber, if it is certain that space available is not sufficient for permanent teeth.
According to Profit, if the discrepancy is of 10 mm or more.
According to Ringerberg, if the discrepancy is of 7 mm or more.
Factors to be considered:
Size of individual permanent teeth is of prime importance.
AP position of lower incisors relative to adjacent skeletal elements and soft tissue i.e. no lingual tipping should occur after serial extraction.
3 methods are there:
1. Dewell’s Method:
- Deciduous canines are extracted at 8 – 9 years of age.
- Deciduous Ist Molars are extracted at 9 – 10 years of age.
- Permanent Ist Premolars are extracted as they erupt.
- Here after extraction of D enucleation is done at site of Ist Premolar so as to accelerate its eruption.
- Extraction of D is done first at 8 years of age.
- Extraction of 4 is done secondly.
- Deciduous canines are extracted lastly.
- Similar to tweeds method.
In patients with bialveolar retrusion, since it further increases discrepancy resulting in “dished-in” facial appearance.
In patients with flat facial contour.
In patients with bialveolar protrusion since retraction of maxillary incisors is desirable and therefore fixed therapy is the treatment of choice.
C. Arch Expansion:
Required when arch discrepancy is more than 5 – 7 mm.
Categories of Expansion:
Results in lateral movement of buccal segments that is primarily dento alveolar.
Produced by fixed appliances, expansion screws etc.
Tendency towards lateral tipping of crowns and lingual tipping of roots is generally seen.
Achieved with the help of Frankle appliance.
Here occlusion is shielded from forces of buccal/ labial musculature producing expansion.
Brieden et al demonstrated that done deposition occurs at lateral aspect of alveolus rather than at midpalatal suture.
Brought by Rapid Maxillary Expansion Appliances.
Here changes are produced in skeletal structures rather than by movement of teeth through alveolar bone.
It separates midpalatal suture and also affects circumzygomatic and circum-maxillary sutures.
Activation is done by giving 900 turn/day (0.2 mm) until lingual cusps of upper posterior teeth approximate buccal cusps of lower posterior teeth.
Retained for 5 mos. after active phase of expansion so as to allow reorganization of midpalatal suture.
Orthodontic Treatment Modalities:
During Primary Dentition:
Nagan et al reported that functional problems which may interfere with normal growth and development.
Correction of anterior and posterior cross bites, AP relationship of maxilla and mandible, deep bite and overbite.
- Class III skeletal relationship particularly if it is due to result of anterior displacement of mandible or due to retarded maxilla.
A protraction headgear attached to an I/O appliance by heavy elastics is the preferred mode of treatment. Worn for 4 – 9 months for full time.
Full fixed edgewise technique or orthodontic braces are rarely in this stage.
Mixed Dentition Stage:
The aim of treatment in this stage is to establish normal sagittal, transverse and vertical relationships of dentition and skeletal components.
Active or passive space maintainers to hold or re-establish leeway space and to derotate permanent Ist molars.
Fixed or Removable Expansion appliances.
Fixed arch wires for molar derotation and up righting, incisor leveling, alignment and intrusion.
Headgear. Ex. Cervical, high-pull or combination of both.
Functional Appliances. Ex. Twin Block, Bionators, Frankel appliance, Herbst appliance etc.
Fixed edgewise therapy can be used.
During this dentition following are used to:
Fixed therapy - To correct alignment and intrusion problems.
Lingual arch or Lip bumper - For arch development.
Headgear Therapy - To correct vertical and sagittal problems.
Early Permanent Dentition:
Space consolidation is done here.
Root parallelism is achieved.
Finishing and detailing of occlusion.
Achieves maximum interdigitation between arches.
Treatment is done with edgewise therapy.
Pediatric Dentistry; Scientific foundations and clinical practice by Stewart; 1st Edi. 1982.
Pediatric Dentistry; Total Patient Care by H.Y.Wei; 1st Edi. 1988.
Dentistry for Children and Adolescents by McDonald; 8th Edi. 2005.
Pediatric Dentistry by Pinkham; 4th Edi. 2005.
Pediatric Dentistry; A clinical approach by Koch; 1st Edi. 2001.
Clinical Pedodontics by Finn; 4th Edi. 1998.
Orthodontics; Current Principles and Techniques by Graber and Swain; 1st Edi. 1995.
Modified Bonded bridge space maintainer; JCPD, Vol. 23, No. 4, 1999; 281-284.