Serial extraction

Dr. Rajeev Singh, pediatric dental surgeon

Kd dental college, Mathura

Contents

• Introduction • History • Definitions• Diagnosis• Dental development• Skeletal development• Muscular development• Rationale• Treatment Objective• Evaluation of the patient• Total space analysis

• Indications• Contra-indications• Advantages of serial extraction• Disadvantages of serial extraction• Sequence of extractions• Treatment• Orthodontic Appliance• Conclusion• Reference

Introduction

• Removal of primary and permanent - definite sequence

• Thorough understanding of orofacial growth and development.

• Lack of understanding and knowledge has created disastrous results

History

• Bunon and Boudet (1743) – first to recommend extraction of teeth in order to relieve crowding

• Linderer (1851) – wrote about extraction to relieve crowding

• Kjellgren (1929) – introduced the term “serial extraction”

• Nance (1940) – father of serial extraction in USA

• Heath (1949) – “planned minimum orthodontic treatment ”

• Dewel (1954), Tweed (1966) – “Pre-orthodontic guidance”

• Hotz (1970) – “Guidance of eruption”

Definitions

• Dewel -The orderly removal of selected primary and permanent teeth in a predetermined sequence.

• Profitt - Serial extraction is the planned sequence of tooth removal that can reduce crowding and irregularity during the transition from primary to permanent dentition.

• Shoba Tandon - The correctly timed, planned removal of certain deciduous and permanent teeth in mixed dentition cases with dentoalveolar disproportion i.e., teeth to supporting bone imbalance in order to:

a) Alleviate crowding of the incisor teeth .b) Allow unerupted teeth to guide themselves into

improved positions. c) Lessen the period of active appliance therapy or

eliminate it .

Diagnosis

• Case selection is the most crucial factor.

• Graber (1971) – The clinician has to assess the interrelationship between three systems

– Dental.

– Skeletal. – Neuromuscular systems.

Dental development

Incisor liability :

• Mayne & Dale (1969) – it as the discrepancy in widths between 4 permanent incisors and their primary counterparts

• Max. teeth - 7.6mm

• Mand. teeth is about 6mm .

• Corrected by combination by 4 factors -

– Interdental spacing of the primary incisor teeth

– Intercanine arch width growth

– Intercanine arch length increases through labial positioning of the erupting permanent incisors

– favorable variations in size ratio between the permanent and primary teeth

Leeway space :

• Nance – the size difference between the primary canine & molars and the

permanent canine & premolars as leeway space.

• 1.8mm in max. and 3.4mm in the mand.

• leeway space is utilized during Mesial drifting of the mand. first molars (class

I molar relationship)

• Spaced primary dentition (early mesial shift)

• Closed primary dentition (late mesial shift)

Skeletal development

• Cephalometric analysis for all cases.

• Hand wrist radiograph – enable the clinician to predict remaining growth & anticipated developmental adjustments.

• The functional articulation between basal bones to each other & their relationship to the cranial base has to be within normal limits.

Muscular development

• Imbalances in musculature should be noted.

• Strain, hypotonicity, hypertonicity, unusual lip lines or markings.

• Adverse oral habits – thumb sucking.

Rationale• Aduss et al (1977) – predict with a fair degree of certainity that there

will not be enough space for the permanent teeth to erupt.

• Graber (1971) –after eruption of the first molars there is no increase in

arch length & also increased arch length by expansion is not very stable.

• Kluemper et al (2000) – early removal of teeth will allow for more

physiologic unassisted movement of adjacent teeth into more favorable

positions.

Treatment Objective

• Performed in different ways

(1) A period of interceptive guidance extending approximately 5 yrs( 71/2 to 121/2 )

(2) An initial period of interceptive guidance extending approximately 4 yrs (71/2 to 111/2) plus second period of multibanded treatment extending approximate 1 yr. ( 111/2 to 121/2).

Class I and specific types of class II fall into this

category.

(3) An initial period of interceptive treatment extending approximate 1 yr (81/2 to 91/2 ),period of interceptive guidance extending approximate 2 yrs (91/2 to 111/2) and second period of multibanded treatment extending approximate 11/2 . ( 111/2 to 13).

Class II and class III malocclusions fall primarily

into this category.

4) A period of multibanded treatment extending for 11/2 to 3 yrs ( 111/2 to 141/2 ).

• Serial extraction is not involved in this treatment wherever possible.

• Avoid extensive treatment in teenage period .

Evaluation of the patientIntraoral radiographs :• Complete series of periapical radiographs

/panoramic radiograph.• Detection of congenital absence of teeth.• Detection of supernumerary teeth.• Evaluation of permanent teeth.• Detection of pathologic conditions in the early

stages.• Assessment of trauma to the teeth.

• Detection of evidence of a true hereditary tooth- size jaw-size discrepancy.

• Determination of size, shape and relative position of unerupted permanent teeth.

• Determination of dental age of the patient.• Calculation of total space analysis.• Detection of root resorption before ,during and after

treatment.• Evaluation of third molars before, during and after

treatment.• Final appraisal of the dental health after orthodontic

treatment.

Cephalometric analysis :

• Evaluation of craniofacial relationships prior to treatment.• Assessment of soft tissue.• Classification of facial pattern.• Calculation of tooth-size jaw-size discrepancies (total

space analysis).• Determination of mandibular rest position.• Prediction of growth and development.• Monitoring of skeletodental relationships during

treatment.• Detection of pathologic conditions before ,during and

after treatment.

Facial photographs :• Evaluation of craniofacial relationships prior to

treatment.• Assessment of soft tissue profile.• Proportional facial analysis.• Total space analysis.• Occlusal curve analysis.• Monitoring of treatment progress.• Study of relationships.

Study models :

• Calculate total space analysis.• Assess and record the dental anatomy.• Assess and record the intercuspation.• Assess and record arch form.• Assess and record the curve of occlusion.• Evaluate occlusion with aid of articulators.• Measure progress during treatment.• Detect abnormalities.

Total space analysis

• Moyer's mixed dentition analysis

• Tanaka and Johnson analysis

Indications• CrowdingMild Crowding: A true arch length discrepancy of 0-2mm may be manifested

as mild irregularities in the incisor region. Observation is usually the best course .If treatment is required proximal slicing or disking can be done with;

i) Hand- held strip, ii) Sand paper disk in a slow speed hand piece, iii) Tapered bur in a high speed hand piece

Moderate crowding:• Arch length discrepancy of less than 5mm • is based on the facial profile, incisor protrusion,

crowding• small amount of expansion is done to accommodate

all the teeth if space loss is 3mm or less • the adjacent tooth is tipped into position with either

a removable appliance or an active lingual arch.

Severe Crowding:

• crowding is so severe (>10mm/arch)

• in the mixed dentition arch expansion is not feasible

• serial extraction is necessary

• A midline displacement of mand. Incisor due to premature exfoliation of primary canine on crowded teeth

• Crowded mand.lateral incisors that have commenced resorbing the roots of the primary canines

• Ectopic eruption of permanent max. first molar indicating a lack of development in the tuberosity area

• facial pattern that is orthognathic /with slight alveolodental protrusion

Contra-indications• Mild to moderate crowding caused by environmental

factors & there is not a substantial lack of space

• Increased overjet or reverse overjet

• Deep overbite or an open bite

• Permanent teeth congenitally missing from the dental arch

• Gross mal-position of teeth ,rotation & crossbite

• Spaced dentition

• Midline diastema

• Extensive caries of Ist permanent molar requireing their removal

• Severe class II,III of dental / skeletal origin

• Cleft lip & palate cases

Advantages of serial extraction

• Mayne(1969) – less potential for iatrogenic orthodontic damage to tooth roots

• Maj (1970) – psychologically ,the child will benefit from earlier correction of esthetics as the anterior teeth spontaneously align themselves

• Yoshihara et al (1999) – aimed at encouraging a measure of self correction in order to shorten the time & complexity of mechanotherapy

• Yoshihara et al (1999) – under appropriate conditions can be used on handicapped patients

• Dale (2000) – retention requirements in serial extraction cases are lessened

• Dale (2000) – reduces appliance treatment time ,the cost of treatment

• Intercepts the developing mal-occlusion as early as possible so as to reduce ,or in rare cases avoid orthodontic treatment

Disadvantages of serial extraction• Aduss et al (1977) – increase in

overbite ,lingual tipping of mand.incisors

thereby decreasing arch length & fixed

appliance therapy after a long period of follow

up

• Jacobs (1987) – early extractions can lead to

space loss and delayed eruption of the

permanent successor

Sequence of extractions• Bunon (1743) – primary canines, first primary molars and

first premolars• Dewels method – C D 4• Tweeds method – D 4 C• Nance method – D4 C • Most satisfactory order

• Removal of first primary molars is sometimes advocated to promote earlier eruption of first premolars

Serial extraction – Class I treatment:

Anterior discrepancy : crowding • Primary canines – to relieve incisor crowding

after eruption of lateral incisor

• Ist primary molar – performed after incisor crowding has improved and the extn site is reduced in size

• When the permanent canines have developed beyond one half root length ,the Ist premolars are extracted

Anterior discrepancy : alveolodental protrusion • Primary Ist molars

• Premolars have to be extracted at half root formation in order encourage their early eruption ahead of canines

• Next the primary canines and Ist premolars are extracted to encourage lingual tipping of incisors

Middle discrepancy : impacted canines

• There may already be premature exfoliation of the primary canines

• The incisors may be splayed out due to crowding in the apical region

• The Ist primary molars should be removed to encourage the premolars to erupt early (at about half root development)

• The premolars are then extracted so that the impacted permanent max. canine will have space to migrate away from the apices of lateral incisors

Tooth germ enucleation in the mandible :

• Extraction of the Ist primary molars with subsequent enucleation of the first premolars

• Indicated when the canine appear to be erupting before the Ist premolars

• This allows distal migration of the erupting canines

Tooth germ enucleation in the maxilla and mandible

• On rare occasions ,in both the max. and mand, the permanent canines will erupt before the premolars

• Extraction of the primary canines followed by the first molars and enucleation of Ist premolars

Orthodontic Appliance Following Serial Extraction Procedure

The most frequently used appliances with serial extractions are;

a) lingual arch,

b) fixed or fixed removable head gears,

c) removable Hawley’s appliance,

d) fixed appliance

Growth spurts

• periods of sudden acceleration of growth

• This sudden increase in growth is termed as growth spurts.

• physiological alteration in hormonal secretion is believed to be the cause

• The following are the timing of growth spurts –• Just before birth• One year after birth• Mixed dentition growth spurt– Boys: 8-11yr– Girls: 7-9yr

• Adolescent growth spurts– Boys: 14-16yr– Girls: 11-13yr

• Pre pubescent take off stage – moderate increment in height velocity

• Pubescent phase – very rapid growth phase

• Post pubescent phase – decelerating of height velocity

Growth trends• proposed by tweed• According to the growth trends he divided

individuals into following groups • Type A• The maxilla and mandible grow together thus

the ANB angle remains unchanged. This is accompanied with cl-l relationship and in mixed dentition, it does not exceed 4.5˚. No treatment is indicated in this case

• Type A subdivision• In this condition maxilla is protruding with the

ANB angle more than 4.5˚. The treatment is to restrict the growth of maxilla allowing the mandible to catch up. The prognosis is good, but at times requires the extraction of premolars

• Type B• The maxilla and mandible are found to grow

forward and downwards with the growth of maxilla exceeding that of the mandible. This type of growth trends have a poor prognosis. Growth of the middle and lower face is predominantly in the vertical directions. This growth trend has poor prognosis.

• Type B subdivision• The ANB angle is large and continuous to

grow, indicating an unfavourable growth trend

• Type C• The maxilla and mandible grow forwards and

downwards, with mandible growing forward more rapidly than the maxilla. The ANB angle seen to be decreasing , with the middle catching up with the maxilla. Treatment is not indicated until the eruption of canine

• Type C subdivision • Mandible is found to be growing more

forward to compare with maxilla. With the mandibular incisors touch the lingual surface of maxillary incisors.

•

Conclusion• Establishment of normal functional occlusion

in balance with supporting structures occasionally requires the reduction of one or more teeth.

• The nature of malocclusion and the age of the patient may be important factors in deciding whether or not to resort to extraction.

• Pedodontist and Orthodontist are mutually dependent on each others skills and their rolls should be viewed as not what is good for the Pedodontist or Orthodontist but what is good for the pati

Reference

• Orthodontics – the current principles and techniques by THOMAS M GRABER & BRAINERD F SWAIN

• Orthodontic principles and practice by GRABER T M• Pediatric dentistry – scientific foundation and clinical

practice by RAY E STEWART, THOMAS K BARBER, KENNATH C TROUTMAN, STEPHAN H Y WEI.

• Text book of pedodontics by SHOBA TANDON• Clinical pedodontics by SIDNEY B FINN• Orthodontics the art and science by S I BHALAJI• Dentistry for child and adolescent by RALPH E McDONALD

& DAVID R AVERY