Preventive and interceptive orthodontics

PREVENTIVE AND INTERCEPTIVE

ORTHODONTICS

BY

DR.JUNAID DAYAR

Orthodontic procedures can be divided as: Preventive Interceptive comprehensive

Preventive orthodontics

Preventive procedures are undertaken in anticipation of development of a problem

Patient and parent education , supervision of growth and development of dentition and craniofacial structures , the diagnostic procedures undertaken to predict the appearance of malocclusion and treatment procedures instituted to prevent the onset of malocclusion

Interceptive orthodontics

Procedure are undertaken when the problem has already manifested.

Orthodontic problems in children can be

divided conveniently into

non skeletal (dental) and skeletal problems , which are treated by tooth movement and by growth modification,

respectively.

Preventive orthodontics

Natal teeth Occlusal relationship problems Eruption Problems Space maintainence

Natal teeth

Present at birth or erupt shortly after birth

Most frequent in lower incisor region Only 10% are supernumerary therefore

removed only when interfere with feeding or causing tongue ulceration

Occlusal relationship problems

a)Cross bites of Dental Origin

b) Oral Habits and Open Bites

Occlusal relationship problems

Cross bites of Dental Origin:

Correction of dental crossbites in the mixed dentition is recommended because it eliminates functional shifts

Minor canine interference leading to mandibular shift

Non skeletal anterior Crossbites

The most common etiologic factor for non skeletal anterior Crossbites is lack of space for the permanent incisors, and it is important to focus the treatment plan on management of the total space situation, not just the crossbite.

If the developing crossbite is discovered before eruption is complete and overbite has not been established the adjacent primary teeth can be extracted to provide the necessary space


Dental anterior crossbites typically develop as the permanent incisors erupt.

Those diagnosed after overbite is established require appliance therapy for correction.

The first concern is adequate space for tooth movement, which usually requires:

1: Bilateral disking,

2: Extraction of the adjacent primary teeth,

3: Or opening space for tooth movement.

Dental posterior cross bite early loss of a second deciduous molar

causing a second premolar to erupt palatally/lingually

retention of a primary tooth can deflect the eruption of the permanent successor leading to a cross bite.

Dental posterior cross bite

Oral Habits and Open BitesOpen bite in a preadolescent child has

several possible causes:

1: The normal transition as primary teeth are replaced by the permanent teeth

2: A habit like finger sucking

3: Tooth displacement by resting soft tissues

Open bite observed during the transitional dentition years

Effects of Sucking Habits

The effect of such a habit on the hard and soft tissues depends on its :

1: Frequency(hours per day)

2: Duration (months/years) With frequent and prolonged sucking,

maxillary incisors are tipped facially, mandibular incisors are tipped lingually , and eruption of some incisors is impeded


As long as the habit stops before the eruption of the permanent incisor, most of the changes resolve spontaneously.


Non-dental Intervention:

As the time of eruption of the permanent incisors approaches, the simplest approach to habit therapy is a

straightforward discussion between the child and the dentist that expresses concern and includes an explanation by the dentist.

Eruption problems

Over-Retained Primary Teeth Supernumerary teeth Delayed Incisor eruption Ankylosed Primary Teeth Ectopic eruptions Transposition Primary failure of eruption Roots shortened by radiation therapy

Over-Retained Primary Teeth

A permanent tooth should replace its primary predecessor when approximately three fourths of the root of the permanent tooth has formed, whether or not resorption of the primary roots is to the point of spontaneous exfoliation.

A primary tooth that is retained beyond this point should be removed.

An over-retained primary tooth leads to: Gingival inflammation Hyperplasia that causes pain and bleeding And sets the stage for deflected eruption paths that

can result in:

(a) irregularity, (b) crowding, (c) crossbite

Over-Retained Primary Teeth

Once the primary tooth is out, if space is adequate,moderately abnormal facial or lingual positioning willusually be corrected by the equilibrium forces of the lip,cheeks and tongue

Supernumerary teeth

Supernumerary teeth can disrupt both the normal eruption of other teeth and their alignment and spacing.

The most common location for supernumerary teeth is the anterior maxilla .

Treatment is aimed at: Extraction of the supernumeraries before

problems arise OR at minimizing the effect if other teeth

have already been displaced

Supernumerary teeth

Delayed Incisor EruptionSometimes incisors fail to erupt even when there is no

retained or overlying primary tooth or supernumerary

teeth present.

Changes in the overlying keratinized tissue occur in long-standing edentulous region

If the delayed incisor is located superficially it can be exposed with a simple soft tissue excision

and usually will erupt rapidly .

When the tooth is more deeply positioned, the overlying and adjacent tissue can be repositioned apically and the crown exposed, which usually leads to normal eruption or the tooth can have an attachment placed and repositioned orthodontically

Delayed Incisor Eruption

Ankylosed Primary Teeth

Appropriate management of an ankylosed primary molar consists of:

maintaining it until an interference with eruption or drift of other teeth begins to occur, then extracting it and placing a lingual arch or other appropriate fixed appliance if needed

Ankylosed Primary Teeth

This radiograph demonstrates both anterior and posterior teeth tipping over adjacent ankylosed primary molars. The ankylosed teeth should be removed if significant tipping and space loss are occurring

Ectopic eruption

Eruption is ectopic when a permanent tooth causes either:

Resorption of a primary tooth other than the one it is supposed to replace

OR resorption of an adjacent permanent tooth.

Ectopic eruption of Lateral incisors Loss of one or both primary canines from ectopic eruption

usually indicates lack of enough space for all the permanent incisors, but occasionally may result solely from an aberrant eruption path of the lateral incisor.

When one primary canine is lost, treatment is needed to prevent or correct a shift of the midline.

Depending on the overall assessment ;the dentist can either:

remove the contralateral canine or

maintain the position of the lateral incisor on the side of the canine loss, using a lingual arch with a spur

If both mandibular primary canines are lost, the permanent incisors tip lingually, which reduces the arch circumference and increases the apparent crowding.

A passive lingual arch to prevent the lingual tipping, or an active lingual arch for expansion may be indicated.

Ectopic eruption of Maxillary First Molars

When only small amounts of resorption

are observed, a period of watchful waiting is indicated because self-correction is possible.

If the blockage of eruption persists for 6 months or if resorption continues to increase, treatment is indicated.

Lack of timely intervention may cause loss of the primary molar and space loss as the permanent molar erupts mesially.

A 20mil brass wire looped and tightened around the contact between the primary second molar and the permanent molar is suggested.

The brass wire should be tightened approximately every 2 weeks

Some other options:

A steel spring clip separator, available commercially, may work if only a small amount of resorption of the primary molar roots exists.

A simple fixed appliance can be fabricated to move the molar distally.

An Arkansas spring

Ectopic eruption of Maxillary Canines

Ectopic eruption of maxillary canines occurs relatively frequently and can lead to either or both of two problems:

( I )impaction of the canine and/or (2) resorption of permanent lateral incisor roots.

There appears to be a genetic basis for this eruption phenomenon, and in some cases it is related to small or missing maxillary lateral incisors

At age 10, if the primary canine is not mobile and thereis no observable or palpable facial canine bulge,a panoramic,occlusal,or periapical radiograph is indicated

Ericson and Kurol found that if the permanent canine crown was overlapping less than half

of the root of the lateral incisor extract the overlying primary canine there was an excellent chance(91%) of normalization of the path of eruption.

When more than half of the lateral incisor root was overlapped,

Early Extraction of the primary tooth resulted in a 64% chance of normal eruption and likely improvement in the position of the canine even if it was not totally corrected

If the canine is not redirected by this procedure,it most likely will remain unerupted in a palatal position or erupt lingual to the maxillary incisors, but another consequence can be the beginning of resorption of the permanent incisor roots.

If that occurs, usually it is necessary to surgically expose the permanent canine and use orthodontic force to bring it to its correct position

Transposition

Transposition is a positional interchange of two adjacent teeth.

Often the best approach is to move a partially transposed tooth to a total transposed position, or to leave fully transposed teeth in that position

Transposition

Primary failure of eruption Diagnosis of primary failure of eruption

often occurs in the late mixed dentition period when some or all the permanent first molars still have not erupted

there is a genetic component to this problem.

The affected teeth are not ankylosed, but do not erupt and do not respond normally to orthodontic force.

Roots shortened by radiotherapy

Some of the irradiated teeth

fail to develop, others fail to erupt, and some may erupt even though they have extremely limited root development. Although the roots are short, light forces can be used to reposition these

teeth and achieve better occlusion without fear of tooth loss

Space maintenance

Early loss of a primary tooth presents a potential alignment problem because drift of permanent or other primary teeth is likely unless it is prevented

IDEAL REQUIREMENTS OF SPACE MAINTAINERS

Should maintain the desired mesiodistal dimensions of the space.

Should not interfere with the eruption of the permanent teeth.

Maintenance of functional movement (physiological) of the teeth.

Should allow for space regainence, when required

Different types of space maintainers Band and Loop Space Maintainers Partial Denture Space Maintainers Distal Shoe Space Maintainers Lingual Arch Space Maintainers

Different types of space maintainers

Interceptive orthodontics

Procedure are undertaken when the problem has already manifested.

Traumatic displacement of teeth

Prior to treatment, multiple radiographs

at numerous vertical and horizontal angulations should be obtained to rule out vertical, and horizontal root fractures that may make it impossible to save the tooth.

Vertical displacement of teeth is a major indication for post-trauma orthodontics

All severely intruded teeth with mature apices become nonvital and fail to erupt.

Early repositioning is critical to reduce the chance of ankylosis, improve access for

endodontic


Vertical displacement of teeth is a major indication for post-trauma orthodontics .

All severely intruded teeth with mature apices become nonvital and fail

to erupt.

Early repositioning is critical to reduce the chance of ankylosis, improve access for


Within 2 weeks of the injury, the intruded tooth

should have been moved enough to allow endodontic

access-ideally, it would be at or near the pre-trauma position.


Pulp therapy is best instituted within 2 weeks to reduce the possibility of resorption.

if further tooth movement of an endodontically-treated tooth will be needed during a second stage of comprehensive treatment, calcium hydroxide can be retained in the pulp chamber until active tooth movement is completed, as a hedge against root resorption


The prognosis for pulp vitality is better in teeth that were not intruded when they were displaced, and in teeth with open apices

follow-up periapical radiographs should be taken at 2 to 3 weeks, 6 to 8 weeks, and 1 year post-injury to check for pathologic changes


Teeth that were extruded at the time of injury and not immediately reduced pose a difficult problem. These teeth have reduced bony support and a poor crown root ratio.

Attempts to intrude them result in bony defects between the teeth, so orthodontic intrusion is not a good plan. When the discrepancy is minor to moderate, reshaping the elongated tooth by crown reduction may be the best plan

Space related problems

Excess space:

Midline diastema:

A small maxillary midline diastema, which is present in many children, is not necessarily an indication for orthodontic treatment.The unerupted permanent canines often lie superior and distal to the lateral incisor roots, which forces the lateral and central incisor roots toward the midline of dental development

Ugly duckling stage

The spaces between the incisors, including the midline diastema, decrease and often completely disappear when the canines erupt .

while their crowns diverge distally this condition of flared and spaced incisors is called the "ugly duckling" stage of development

These spaces tend to close spontaneously when the canines erupt and the incisor root and crown positions change

The ugly duckling phase

Midline diastema

A small but unesthetic diastema (2 mm or less) can be closed in the early mixed dentition by tipping the central incisors together.

Midline diastema(2mm/less)

When a larger diastema (>2mm) is present

Causes can be:

1. A midline supernumerary tooth

2. Missing permanent lateral incisors

3. digit-sucking habits

What to do: Maxillary occlusal or periapical radiograph Bodily mesiodistal movement, an anterior

segmental archwire from central to central incisor or the classic 2 x 4 appliance

Permanent retention

A fixed retainer to maintain diastema closure.A bonded 17.5mil multistrand wire with loops bent into the endsis bonded to the lingual surfaces of anterior teeth to serve as aPermanent retainer. This flexible wire allows physiologic mobilityOf the teeth and reduces bond failure but can be used onlv whenthe overbite is not excessive.

Maxillary Dental Protrusion and Spacing Treatment for maxillary dental protrusion

during the early mixed dentition is indicated only when the maxillary incisors protrude with spaces between

them and are esthetically objectionable or in danger of traumatic injury

: it is often a sequel to prolonged thumb sucking

Maxillary Dental Protrusion and Spacing If there is adequate vertical clearance

and space within the arch, maxillary incisors that have been displaced by a sucking habit can be tipped lingually with a removable or a fixed appliance

Maxillary Dental Protrusion and Spacing

Missing Permanent Teeth

Missing Second Premolars: If the patient has an ideal or an acceptable

occlusion, maintaining the primary second molars is a reasonable plan

if the space profile and jaw Relationships are good or some what

protrusive,i t is possible to extract primary second molars that have no successor at age 7 to 9 and allow the first molars to drift mesially

Retention of primary molar

Extraction of primary molar to allow mesial drift of permanent molar

Missing Maxillary Lateral Incisors two sequelae usually is observed:

1)the erupting permanent canine resorbs

the primary lateral incisor and spontaneously substitutes for the missing lateral incisor.

2) the primary lateral is retained when the permanent canine erupts in its normal position

Long-term retention of primary laterals, in contrast to primary molars, is almost never an acceptable plan

Missing Maxillary Lateral Incisors ultimate treatment is substitution of the

canine for the lateral or opening space for a prosthetic replacement

Missing Maxillary Lateral Incisors

Auto transplantation.

In patients with a congenitally missing tooth or teeth in one area but crowding in another ,autotransplantation also is a possible solution.

Teeth can be transplanted from one position to another in the same mouth with a good prognosis for long-term success if this is done when the transplanted tooth has approximately one half of its root formed."

Auto transplantation

Transplantation is most commonly used to move premolars into the location of missing incisors. It can also be used to replace missing first molars with third molars

Space Regaining

After premature loss of a primary tooth, space may be lost from drift of other teeth

Up to 3 mm of space can be reestablished in a localized area with relatively simple appliances and a good prognosis

Maxillary Space Regaining Generally, space is easier to regain in

the maxillary than in the mandibular arch, because of the increased anchorage for

removable appliances afforded by the palatal vault and the possibility for use of extraoral force (headgear)

Maxillary Space Regaining

Maxillary Space Regaining A removable appliance retained with Adams'

clasps and incorporating a helical fingerspring adjacent to the tooth to be moved is very effective. This appliance is the ideal design for tipping one molar .

One posterior tooth can be moved up to 3 mm distally during 3 to 4 months of

full-time appliance wear. The spring is activated approximately

2 mm to produce I mm of movement per month

For unilateral bodily space regaining, a fixed intra-arch appliance is preferred

Maxillary Space Regaining If bodily movement of both permanent

maxillary first molars is necessary in regaining space this can be accomplished by using a banded and bonded fixed appliance or headgear

Sometimes both molars need to be moved distally but one requires substantially more movement than the other. To accomplish this, an asymmetric facebow with a neckstrap attachment can be used

Maxillary Space Regaining

Mandibular Space Regaining

For unilateral mandibular space regaining, the best choice is a fixed appliance and an archwire

a lingual arch can be used to support the tooth movement and provide anchorage when used in conjunction

with a segmental archwire and coil spring


If space has been lost bilaterally there

are two choice:

1) an adjustable lingual arch and

2) a lip bumper.

Serial extraction

Indications:

1.Straight profile

2.Class I malocclusion

3.Arch length discrepency in maxilla should be 11 mm while in mandibular arch 10.5 mm

Serial extraction

Contraindications:

1. Convex profile

2. Class II malocclusion

3. Low angle case

4. High angle case

Advantages of serial extraction

Reduces the severity of malocclusion Reduces the extent of mechanotherapy Reduces the duration of treatment

Disadvantages of serial extraction Chances of increasing overbite Canines may fail to migrate distally Anterior teeth may tip lingually

Methods of serial extraction Dewel’s method (cd4)

Tweed’s method (d4c)

Preventive and interceptive orthodontics

Health & Medicine

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