Class II division 2
Class II division 2
The class II division 2 differs from division 1 by the following characteristic: the discrepancy between the upper and lower teeth does not match the discrepancy between the upper and lower teeth where the molars and canines are located (red and blue arrows). The upper incisors are tipped backward and hide the fact that the lower jaw is farther back. Moreover, the upper incisors hide the lower teeth completely. This type of exaggerated vertical covering is called supraocclusion (deep overbite).
Notice the upper left lateral incisor which is tipped forward unlike the three other incisors. The classic class II division 2 shows the lateral incisors tipped forward and the central incisors tipped backward.
Oral piercing and gingival recession
A gingival recession is observed where the upper right canine is located (green circle). This recession was caused by the rubbing of a piercing jewel internal fastener for which we can see the cicatricial hole on the upper lip (blue circle). A gingival graft of subepithelial connective tissue was necessary to cover up the exposed root and increase the width of the band of keratinized gingiva.
Seen from above, the maxillary arch shows an anterior flattened shape compared to a more oblong and narrower shape observed on the maxillary arch of a class II division 1 or a parabolic shape in normal dentition.
Cephalometric profile view
This cephalometric X-ray shows a backward tipping of the upper incisors (linguoversion or palatoversion) that hides the posterior discrepancy of the lower jaw.
The exaggerated overbite of the upper incisors over the lower incisors is easily recognizable.
Notice that the chin projection is anterior to the lower teeth. It is as if the bone segment holding the lower teeth had been retained backward while the basal bone continued its growth forward. This situation characterized by the lower teeth located posteriorly on the basal bone is called dentoalveolar retrusion.
If we draw a tangent line from the tip of the nose to the tip of the chin, you notice that the lips are posterior to this line, which emphases the visual effect of a nose and chin projection.
The lower lip is hemmed forward and the labiomental groove is emphasized (red arrow).
The problems list in the 3 planes in space can be summarized as:
- a length problem: the lower teeth are posterior to the upper teeth, but the chin is relatively well positioned,
- a height problem: the lower third of the face is shorter than normal,
- widthwise: the maxillary arch has an adequate width.
Let’s notice on this panoramic X-ray the presence of the upper and lower third molars which have not erupted in the mouth yet. On the mandibular arch, the third molars do not have the necessary biological space to take position between the second molar and the vertical part of the mandible called the ramus. Their prophylactic removal is recommended since they will not have enough space in the mouth, but also mainly because an orthognathic surgery is planned and the cutline passes through the site of the third molar. We will come back to this subject in another section of this site.