Orthodontics: Class II, Division 2

Class II, Division 2 Malocclusion

• Characterized by an inverted or decreased axial inclination of upper teeth, also known as root proclined or axial protrusion
• Leads to retroclined Class II, Division 2

Etiology

• Eruption pattern of the upper incisors is very vertical, genetically conditioned
• Characteristic morphology of the incisor with a greater corono-root angle and smaller buccopalatal width

Classification

• Van der Linden (1983) classification:
  • Type A: Excess of upper space, no crowding, retroclination of all 4 upper incisors
  • Type B: Mild upper crowding, retroclination of the central incisors, and proclination of the lateral incisors
  • Type C: Severe upper crowding, retroclination of all upper incisors, and ectopic buccal canines
• Canut (1986) classification:
  • Based on the skeletal class and position of the lower incisor
  • Type I: Class I molar, Class I skeletal, brachyfacial pattern, retrusion of the lower incisors, and moderate-severe lower crowding
  • Type II: Class II molar, Class II skeletal mandibular, normal position of lower incisors, and no lower crowding
  • Type III: Class II molar, retrusion of lower incisors, skeletal class I, brachyfacial, and crowding varies in the lower arch
  • Type IV: Class II molar, retroclination of upper central incisors, dolicofacial pattern, normal position of lower incisors, and no lower crowding

Definition

• Defined by Angle (1907) as "When the buccal groove of the first mandibular molar occludes distal to the mesiobuccal cusp of the first maxillary molar, with retroclination of the maxillary central incisor"

History

• Case 1921: "Upper apical protrusion"
• Hellman 1922: "Upper dentoalveolar malocclusion"
• Lundstrom 1925: "Upper apical mesialisation"
• Mayrhofer: "deep bite" with increased overbite and retrusion of the upper central incisors

Cephalometric Characteristics

• Skeletal class I (Swann, Hedges, Renfroe...)
• Skeletal mandibular class II (Raga, Godiawala)
• Skeletal maxillary class II (Logan)
• Brachyfacial pattern with decreased lower facial height and goniac angle (Hellman, Renfroe, Hedges etc...)

Prevalence

• 3-4% of the general population
• 2-9% of the malocclusive population
• Female predominance (3:1)

Extraoral Analysis

• Frontal:
  • Reduced lower third
  • Increased bigonial distance
  • Correct lip sealing
  • Thick, hypertonic lower lip
  • Marked labiomental fold
  • Variable gingival smile
• Lateral:
  • Reduced lower third
  • Convex/straight profile
  • Labial retrusion varies
  • Harmonious lip sealing
  • Lower lip prolapse

Dental Arches Analysis

• U-shaped upper arch with anterior group retrusion
• Variable lower arch (U or V shape)