Serial Extraction

 

Serial Extraction .ppt, powerpoint slide on serial extraction

Outline

• Introduction
• Definitions
  • Crowding
  • Serial Extraction
• History of Serial Extraction
• Rationale
• Indications
• Contraindications
• Diagnosis
• Procedure
• Advantages
• Disadvantages
• Conclusion

Introduction

Interceptive orthodontics has evolved significantly over the years, leading to a better understanding of clinical possibilities and limitations. The term "interceptive orthodontics" reflects this evolution, replacing the earlier term "preventive orthodontics." One of the procedures performed under interceptive orthodontics is serial extraction.

Crowding

Crowding of teeth arises from a faulty relationship between jaw size and tooth size.

• The size of the jaw influences the relationship of the apices to one another, while the arch perimeter limits the relation of the crowns and tooth size comes in between.

Serial Extraction

Serial extraction is a form of interceptive orthodontic treatment designed to alleviate crowding early, allowing permanent teeth to erupt in good alignment, thereby reducing or avoiding the need for later appliance therapy.

• Crowding may manifest as early as 7 years of age with the eruption of incisors, and at 10 to 12 years for canines and premolars. In late teens, it may present as late labial segment imbrications.
• It is defined as the timely planned extraction of primary, and ultimately secondary teeth, to relieve crowding, particularly in incisor crowding. Developed in Europe, it aims to address severe space problems.

Definition of Serial Extraction

Serial extraction encompasses a series of planned, sequential extractions of specific primary and secondary teeth, allowing for spontaneous alignment of crowded incisors.

• The term "serial extraction" was coined by Kjellgren in 1948, a Swedish dentist, and is typically conducted when patients are 8-9 years old with mild to moderate incisor crowding.

History of Serial Extraction

• Bunon in 1743 must be credited with the original concept, but Kjellgren and Hotz popularized the ideal.
• Kjellgren’s "serial extraction" and Hotz’s "guidance of eruption" emerged simultaneously in Europe during the late 1940s.
• Nance also popularized this technique in the USA during the 1940s, calling it "planned & progressive extraction."

Rationale

Serial extraction is predicated on two principles:

1. Arch Length-Tooth Material Discrepancy:
   • When excess tooth material exists compared to arch length, it is advisable to reduce tooth material for stable results. This reduction occurs through selective extractions to guide remaining teeth into normal occlusion.
2. Physiologic Tooth Movement:
   • Human dentition has a natural tendency to move towards extraction spaces. Selective removal of teeth guides other erupting teeth into these spaces.

Indications

• Patients should be between 8 to 9 years of age with incisor crowding.
• The fundamental arch relationship should be normal (Angle Class I), indicating harmony between the skeletal and muscular systems.
• Key indicators for serial extraction:
  • Absence of physiological spacing
  • Unilateral or bilateral premature loss of deciduous canines with midline shifts
  • Malpositioned or impacted lateral incisors erupting palatally
  • Markedly irregular or crowded upper or lower anteriors
  • Localized gingival recession in the lower anterior region
  • Ectopic eruption of teeth
  • Mesial migration of buccal segments
  • Abnormal eruption patterns & sequences
  • Lower anterior flaring
  • Ankylosis of one or more teeth
• Normal or reduced overbite should be present, with all teeth visible on radiographs and positioned for eruption.
• There should be a significant arch perimeter deficiency of 10mm or more, and the first premolar should be closer to eruption than canines.

Contraindications

Serial extraction is contraindicated in certain conditions, including:

• Class II & III malocclusion with skeletal abnormalities
• Spaced dentition
• Anodontia/oligodontia
• Open bite & deep bite
• Class I malocclusion with minimal space deficiency
• Unerupted malformed teeth (e.g., dilaceration)
• Extensive caries or heavily filled first permanent molars
• Mild disproportion between arch length and tooth material that can be treated by proximal stripping.

Diagnostic Procedure

1. Assess for malocclusion through clinical examination, determining the need for investigation and collection of diagnostic records.
2. Comprehensive assessment of dental, skeletal, and soft tissue is necessary.

Investigations Required

• Study Models:

  • Assess the dental anatomy of teeth
  • Evaluate intercuspation of teeth
  • Analyze arch form and curve of occlusion
  • Model analysis (arch perimeter analysis, Carrey's analysis, mixed dentition analysis).

• Radiographs:

  • Intraoral (e.g., periapicals, occlusal views)
  • Extraoral (e.g., cephalometric, panoramic views)
  • Essential for detecting congenitally missing teeth, bony pathosis, assessing root development stages, determining dental age, and analyzing craniofacial structures.

Summary of Diagnostic Exercise

• Assess dental, skeletal, and soft tissues.
• Identify essential tooth material-arch length discrepancies.
• An arch length deficiency of not less than 5-7mm should exist.
• Conduct study model analysis to identify discrepancies.
• Undertake mixed dentition analysis for erupting buccal teeth.
• Comprehensive cephalometric examination to evaluate underlying skeletal relationships.

Procedures

Different procedural methods have been described, such as:

• Dewel’s Method (1978): Proposes a 3-number serial extraction procedure involving:
  • Removal of deciduous canines to create space for incisor alignment (ages 8-9).
  • Removal of deciduous first molars one year later to encourage eruption of first premolars.
  • Extraction of first premolars for eruption space for permanent canines.
• Tweed's Method (1966): Involves extracting first deciduous molars around age 8, followed by simultaneous extraction of first premolars and deciduous canines.
• Nance's Method: Similar to Dewel's and Tweed's methods.

Advantages of Serial Extraction

• Treatment is physiologic, guiding teeth into normal positions using physiological forces.
• Avoids psychological trauma associated with malocclusion by correcting it at an early age.
• Can relieve incisor crowding and achieve good alignment without orthodontic appliances.
• Simplifies later comprehensive orthodontic treatments, reducing duration of fixed treatment.
• Promotes better oral hygiene, thus minimizing caries risk.
• Preserves the health of investing tissues and achieves more stable results with tooth material in harmony with arch length.
• Low cost and often manageable within the scope of general practitioners.

Disadvantages of Serial Extraction

• Treatment time is prolonged, spanning over 2-3 years.
• Requires frequent dental visits, necessitating patient cooperation.
• Extraction of buccal teeth may deepen the bite.
• Gradual closure of extraction spaces can lead to tongue thrust.
• May cause psychological issues for children experiencing multiple extractions at a young age.
• Improper extraction sequences can delay eruption of secondary teeth.
• Risk of space loss after extraction due to delays.
• Poorly executed serial extraction programs can reduce arch length due to mesial migration of buccal segments.

Conclusion

Effective preventive techniques can significantly reduce malocclusion and its associated complications.