Classification of Dental Impactions: A Detailed Guide for Dental Students

Related Resources

• Dental Impaction: A Comprehensive Guide for Medical and Dental Professionals
• Radiographic Assessment of Dental Impactions: Techniques and Interpretation
• Management of Impacted Teeth: Surgical Approaches and Techniques
• Complications of Dental Impactions: Prevention and Management
• Preventive Approaches to Dental Impactions: Early Intervention and Management

Introduction to Dental Impaction Classifications

Dental impaction classifications provide a systematic approach to categorizing impacted teeth based on their position, angulation, and relationship to surrounding structures. These classification systems are frequently tested in NEET previous year question papers and are essential for effective clinical communication and treatment planning.

Mandibular Third Molar Classifications

Pell & Gregory Classification

This widely used classification system evaluates mandibular third molars based on two key relationships:

Relationship to the Anterior Border of the Mandibular Ramus

• Class A: Sufficient space available between the anterior border of the ramus and the distal surface of the second molar
• Class B: Reduced space available, with approximately half of the crown covered by the ramus
• Class C: No space available, with the crown completely within the ramus

Clinical Significance: Class A impactions are generally easier to remove, while Class C impactions present significant challenges due to limited accessibility.

Relationship to the Occlusal Plane

• Position 1: The occlusal surface of the impacted tooth is at the same level as the occlusal plane of the second molar
• Position 2: The occlusal surface is between the occlusal plane and cervical line of the second molar
• Position 3: The occlusal surface is below the cervical line of the second molar

Clinical Significance: Position 1 impactions are typically the easiest to remove, while Position 3 impactions are the most challenging due to their depth and bone coverage.

Winter's Classification

This classification is based on the angulation of the long axis of the impacted third molar relative to the long axis of the second molar:

• Mesioangular (43%): The crown is tilted toward the second molar
• Horizontal (3%): The long axis is perpendicular to the second molar
• Vertical (38%): The long axis is parallel to the second molar
• Distoangular (6%): The crown is tilted away from the second molar
• Inverted: The crown points toward the mandibular border
• Buccoversion: The tooth is tilted toward the buccal side
• Linguoversion: The tooth is tilted toward the lingual side

Clinical Significance: Mesioangular impactions are generally easier to remove, while distoangular and inverted impactions often present significant challenges.

ADA AAOMS Classification

The American Dental Association and American Association of Oral and Maxillofacial Surgeons classify impactions based on surgical complexity:

• 07220: Soft tissue impaction requiring incision of overlying soft tissue
• 07230: Partially bony impaction requiring flap elevation and bone removal
• 07240: Complete bony impaction requiring extensive bone removal and tooth sectioning
• 07241: Complete bony impaction with unusual surgical complications

Clinical Significance: This classification helps in determining the surgical approach, instrumentation, and billing.

Maxillary Third Molar Classifications

Maxillary third molars are classified based on:

Angulation

• Vertical (63%): Most common
• Distoangular (25%): Second most common
• Mesioangular (12%): Less common
• Horizontal: Rare
• Inverted (1%): Very rare

Relationship to Maxillary Sinus

• Sinus Approximation: Close proximity to the maxillary sinus floor
• Non-Sinus Approximation: No close relationship with the sinus

Clinical Significance: Sinus approximation cases require special attention to prevent oro-antral communication during extraction.

Maxillary Canine Classifications

Maxillary canines are the second most commonly impacted teeth after third molars. Their classification is based on position:

Based on Position in the Dental Arch

• Buccal Impaction: Canine positioned on the buccal surface
• Palatal Impaction: Canine positioned in the palate (more common, approximately 85%)
• Alveolar Impaction: Canine positioned within the alveolar process
• Combined Impaction: Canine positioned in both palatal and labial aspects
• Impaction in Edentulous Maxilla

Clinical Significance: The approach for surgical exposure or extraction varies significantly based on the position, with palatal impactions generally requiring more extensive flap designs.

Difficulty Assessment Classifications

WHARFE Assessment by MacGregor

This comprehensive scoring system evaluates:

• W: Winter's classification (angulation)
• H: Height of the mandible (measured in mm)
• A: Angulation of the third molar (measured in degrees)
• R: Root shape (favorable, complex, or unfavorable)
• F: Follicle development (normal, possibly enlarged, or enlarged)
• E: Exit path (space available, distal cusps covered, mesial cusps covered, or both cusps covered)

Clinical Significance: Higher scores indicate greater extraction difficulty.

Pederson Difficulty Index (1988)

This index assigns values to three key factors:

1. Spatial Relationship: Mesioangular (1), horizontal/transverse (2), vertical (3), distoangular (4)
2. Depth: Level A (1), Level B (2), Level C (3)
3. Ramus Relationship/Space Available: Class 1 (1), Class 2 (2), Class 3 (3)

The sum of these values indicates the extraction difficulty:

• 3-4: Slightly difficult
• 5-7: Moderately difficult
• 7-10: Very difficult

Clinical Significance: This index helps in preoperative planning and patient counseling regarding the complexity of the procedure.

Instruments Used for Impaction Management

Understanding the instruments required for different types of impactions is crucial for effective treatment. Key instruments include:

• Periosteal elevator
• Austin's retractor
• Extraction forceps
• Bone chisels and mallets
• Elevators (straight, Cryer's, Warwick James)
• Surgical handpieces and burs
• Needle holders and suture materials

Clinical Significance: Proper instrument selection and usage significantly impact the success of impaction management.

Conclusion

Mastery of these classification systems is essential for dental professionals and students preparing for the NEET MDS. Understanding the various types of impactions and their management approaches enables better treatment planning and improves surgical outcomes.

For dental students using flashcard applications for NEET or other revision tools for NEET, these classifications should be prioritized in your study materials. Regular practice with NEET mock tests can help reinforce your understanding of these concepts.

Continue your learning journey by exploring our related articles on radiographic assessment, management techniques, complications, and preventive measures for dental impactions.