13 May IMPACTIONS OF WISDOM TEETH
The third molar, popularly known as the wisdom tooth, is the last to erupt and is positioned last at the back of your teeth. Normally, erupted wisdom teeth are rare in clinical situations, while impacted wisdom teeth are common. Malpositioned wisdom teeth could be defined as impacted wisdom teeth.
HOW DO WISDOM TEETH GET IMPACTED?
People have different jaw sizes. Some have enough space for a wisdom tooth to erupt normally; most people have a jaw with limited space for the tooth to naturally erupt. Insufficient space can inhibit or prevent factor of the migration and eruption of the wisdom tooth. Therefore, the wisdom tooth becomes impacted when its growth stays in a certain state. Sometimes, a tooth may erupt at the wrong angle: partially or not.
CLASSIFICATION OF IMPACTED WISDOM TEETH
Mesial
The resorption of the alveolar bone caused the wisdom tooth to be displaced forward damaging the alveolar septum (triangular shape) between the roots of the wisdom tooth and second molar.
Spacing and Distal
Spacing impaction indicates that there is increased distance from the mesial crown edge of the wisdom tooth to the distal root of the second molar. In addition to the increased distance, distal impaction is also involved with the direction of crown inclination
Inclination
The angle formed by the long axis of the wisdom tooth and the second molar is less than 90°.
Embedded
Embedding refers to the depth of the crown of the wisdom tooth that is embedded in the distal crown, neck, or root of the second molar, which can be expressed as 1/2, 1/3, or 1/4 of the diameter of the embedded horizontal molar (indicates the degree of second molar injury).
Vertical
When the long axis of the crown and root of the wisdom tooth is parallel to that of the second molar, it is in the state of vertical impaction.
Horizontal
When the angle formed by the long axis of the wisdom tooth and that of the second molar is approximately 90°.
Reverse
The occlusal plane of the wisdom tooth faces a distal direction. When the angle formed by the long axis of the wisdom tooth and that of the second molar is less than 90°, it is inclined. If the angle equals 90°, it is horizontal.
Underneath (Mandibular Subapical)
For the mandibular impacted teeth, draw the long axis lines for the wisdom tooth and the second molar. Extending from the intersection of the long axis and occlusal plane of the wisdom tooth toward the long axis of the second molar, if the extended line is underneath the apex of the second molar, such impacting status is a mandibular subapical impaction
Upper (Maxillary Subapical)
For the maxillary impacted teeth, if a line is extended from the intersection of the long axis and the occlusal plane of the wisdom tooth toward the long axis of the second molar, and such extension line is above the apical part of the second molar, the state of the wisdom tooth is a maxillary subapical above impaction.
Front and Rear
If the impacted wisdom tooth locates underneath the root or in front of the root of the second molar, it defines as a front. If the impacted wisdom tooth locates within a distance of the mesiodistal diameter of the wisdom tooth crown to the second molar, it defines as rear. It applies to the upper and lower impacted wisdom teeth.
Inverse
The status that the crown of the wisdom tooth is facing toward the root of the second molar is called inversion of the wisdom tooth. When the angle formed by the long axis of the wisdom tooth and that of the second molar is more than 90°, it is regarded as an inverted state.
Front and Rear
If the impacted wisdom tooth locates underneath the root or in front of the root of the second molar, it defines as a front. If the impacted wisdom tooth locates within a distance of the mesiodistal diameter of the wisdom tooth crown to the second molar, it defines as rear. It applies to the upper and lower impacted wisdom teeth.
High, Middle, and Low Level
Draw two horizontal lines perpendicular to the long axis of the second molar. One horizontal line is drawn between the mesial and distal contact points of the crown, and the other is at the pulpal floor of the second molar. The two horizontal lines divide the second molar into three parts.
For the mandibular wisdom tooth, a high level indicates that the wisdom tooth is located above the height of the contour of the crown of the mandibular second molar; a middle level indicates the wisdom tooth is located between the height of the contour of the crown and the pulp chamber floor of the second molar, and a low level indicates that the wisdom tooth is located in between the pulp chamber floor and the apex of the second molar.
The levels of impaction for maxillary wisdom teeth are defined contrarily. Draw a perpendicular line from the occlusal plane to the long axis of the wisdom tooth. Draw a line at the intersection of the two lines at the occlusal plane to the second molar.
(a, b) Mesioangular impacted middle-level wisdom tooth in the maxilla. (c) Mesially and vertically impacted high-level wisdom tooth in the maxilla. (d) Mesially and vertically impacted low-level wisdom tooth in the maxilla
(a) Mesioangular impacted high-level wisdom tooth in the mandible. (b) Mesioangular impacted low-level wisdom tooth in the mandible. (c) Mesioangular impacted middle-level wisdom tooth in the mandible. (d) Mesially and horizontally impacted middle-level wisdom tooth in the mandible
Malposition
The central axis of the second molar is located on the dental arch curve. If the central axis of the wisdom tooth is perpendicularly deviated from the dental arch curve to its buccal, palatal, or lingual side, the wisdom tooth is defined as malpositioned.
- Buccal malposition: the central axis of the maxillary or mandibular wisdom teeth deviates to the buccal side of the dental arch curve distal to the central axis of the second molar.
- Lingual malposition: the central axis of the mandibular wisdom teeth deviated to the lingual side of the dental arch curve distal to the central axis of the mandibular second molar.
- Palatal malposition: the central axis of the maxillary wisdom teeth deviated to the palatal side of the dental arch curve distal to the central axis of the second molar.
Buccal, Lingual, and Palatal
The “direction” refers to the direction of the crown. The crown of the wisdom teeth could be facing toward the buccal, palatal, or lingual side, but its central axis remains within the dental arch curve.
Conclusion
The Impacted teeth can cause problems to your oral health. Consult your doctor as soon as possible. Although at any age people can set an appointment with an oral surgeon for removal of the wisdom teeth, it is recommended to remove them between 18 to 24 years of age. Early removal equals fewer complications.
