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Radiographic evaluation of mandibular third molar eruption space
1Jordan University of Science and Technology, Department of Restorative Dentistry, Faculty of Dentistry, Irbid.
Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontics
|September 30, 1999
Summary
Inadequate space is the primary factor in mandibular third molar impaction. Most impacted third molars show a smaller space-to-crown width ratio, indicating a lack of room for eruption.
Area of Science:
- Dentistry
- Orthodontics
- Oral Surgery
Background:
- Third molar impaction is a common clinical issue.
- Understanding the factors contributing to impaction is crucial for diagnosis and treatment planning.
Purpose of the Study:
- To investigate variables in third molar and arch dimensions in subjects with impacted versus erupted mandibular third molars.
Main Methods:
- Standardized panoramic radiographs of 134 subjects (average age 19.8 years) were analyzed.
- Radiographic features included tooth angulation, eruption level, root development, crown width, retromolar space, and gonial angle.
- Analysis focused on mesioangular inclination for the impacted group.
Main Results:
- The retromolar space was significantly smaller in the impacted group (P < .001).
- Third molar space/crown width ratios were significantly lower in the impacted group (0.78) compared to the erupted group (1.06) (P < .001).
- A strong positive relationship exists between impaction frequency and angulation, and an inverse association with retromolar space.
Conclusions:
- Inadequate arch space is the most significant variable associated with mandibular third molar impaction.
- The majority of impacted third molars exhibit space/crown width ratios less than 1, confirming limited space as a key determinant.