Occlusion Classifications

Class I Occlusion

• Molar relationship: Maxillary first molar's mesiobuccal (MB) cusp occludes with the MB groove of the mandibular first molar.
• Canine relationship: Maxillary canine occludes with the distal half of the mandibular canine and the mesial half of the mandibular first premolar.
• Maxillary first molar positioning: Slightly posterior to the mandibular first molar, with the mesiobuccal cusp in line with the buccal groove of the mandibular first molar.
• Facial profile description: Termed mesognathic, indicating a neutral or straight facial appearance.

Class II Occlusion

• Molar relationship: Maxillary first molar's MB cusp occludes mesial to the MB groove of the mandibular first molar by more than the width of a premolar.
• Canine relationship: Distal surface of the mandibular canine is positioned distal to the mesial surface of the maxillary canine by at least the width of a premolar.
• Maxillary first molar positioning: Either even with or anterior to the mandibular first molar, with the buccal groove of the mandibular first molar being distal to the mesiobuccal cusp of the maxillary first molar.
• Facial profile description: Termed retrognathic, indicating a more recessed jaw appearance.

Class II Occlusion Division 1

• Maxillary anterior teeth are protruded facially compared to the mandibular anteriors.
• Characterized by a deep overbite, with significant vertical overlap of teeth.

Class II Occlusion Division 2

• Maxillary central incisors are either upright or retruded.
• Lateral incisors may be tipped labially or overlapping the central incisors, also associated with a deep overbite.

Class III Occlusion

• Molar relationship: Maxillary first molar's MB cusp occludes distal to the MB groove of the mandibular first molar by more than the width of a premolar.
• Canine position: Distal surface specifics were not detailed but indicate a contradiction to previous classifications.
• Maxillary first molar positioning: More posterior than normal; buccal groove of the mandibular first molar is mesial to the mesiobuccal cusp of the maxillary first molar.
• Facial profile description: Termed prognathic, indicating a prominent jaw or forward facial structure.

Explore key concepts of occlusion classifications in dentistry with this set of flashcards. The focus is primarily on Class I occlusion definitions and the relationships between molars and canines. Perfect for dental students and professionals looking to enhance their knowledge in dental occlusion.