The Ashley-Howe model analysis is a method used in orthodontics to assess the relationship of the dental arches and the position of the teeth, particularly in the context of planning orthodontic treatment. This analysis is particularly useful for evaluating the transverse dimension of the dental arches and understanding how the maxilla (upper jaw) and mandible (lower jaw) relate to each other.

Measurement Parameters:

• The analysis involves measuring specific distances and angles on dental casts or models. Key measurements may include:
  • Intercanine Width: The distance between the cusp tips of the canines.
  • Interpremolar Width: The distance between the cusp tips of the first premolars.
  • Intermolar Width: The distance between the cusp tips of the first molars.
• These measurements help in determining the transverse relationships of the dental arches.

Classification:

• The results of the Ashley-Howe analysis can help classify the dental arch relationships into different categories, such as:
  • Normal: Where the measurements fall within the expected range.
  • Narrowed: Indicating a constricted arch that may require expansion.
  • Widened: Indicating a broader arch that may need to be reduced or managed differently.

Clinical Application:

• The Ashley-Howe model analysis is particularly useful in treatment planning for orthodontic cases involving:
  • Crossbites: Where the upper teeth are positioned inside the lower teeth.
  • Crowding: Where there is insufficient space for teeth to erupt properly.
  • Expansion Needs: Determining if a patient requires arch expansion to correct transverse discrepancies.

Treatment Implications:

• Based on the analysis, orthodontists can decide on appropriate treatment modalities, which may include:
  • Orthodontic Appliances: Such as expanders to widen the arch.
  • Extraction: In cases of severe crowding or when space needs to be created.
  • Comprehensive Orthodontic Treatment: To align the teeth and improve occlusion.