Case• 17. A loose tooth
SUMMARY
A 25-year-old man presents in your general dental practice with a loose tooth. Identify the cause and summarize the treatment options.
Complaint
The patient complains of a loose tooth and points to his upper left lateral incisor which is crowned. He says it is uncomfortable when it moves and has become so mobile that he thinks it may fall out.
History of complaint
He has noticed that the tooth has become progressively looser over the last few months and would like a replacement. There has been no pain associated with the tooth but he is aware of an unpleasant taste which appears to emanate intermittently from his upper front teeth.
Dental history
The patient had been a regular attender at another dental practice for many years until he moved to your area. He is motivated and does not wish to lose any teeth.
Four years previously, the lateral and central incisors had been fractured in an accident at work. Both teeth sustained class II coronal fractures but were initially left untreated. Several months later another dental practitioner provided some restorations on both teeth and shortly afterwards the patient asked for the lateral incisor to be crowned because he was unhappy with the appearance.
Medical history
The patient has insulin-controlled diabetes. Otherwise he is fit and well and is taking no medication.
Examination
Extraoral examination
No submandibular or cervical lymph nodes are palpable.
Intraoral examination
The patient has an extensively restored dentition with a crowned upper left lateral incisor that is grade II mobile buccolingually but not vertically. There is generalized but mild redness and delayed bleeding on probing around the gingival margin associated with a small amount of plaque at the crown margin. However, there is no increase in probing depth around this tooth. There is no evidence of caries on any teeth and generally the periodontal condition is good. The adjacent teeth are firm. No sinuses are present to explain the bad taste and no pus is detected on periodontal probing.
▪ What additional questions might you ask?
Did you notice the mobility suddenly increase or hear a crack from the tooth? The marked mobility without evidence of periodontitis suggests a root fracture.
The patient has noticed no sudden increase in mobility.
▪ How would you clinically assess the possibility of root fracture?
By determining the axis of rotation of the mobile crown. Apply pressure forwards and backwards to identify how far down the root the axis of rotation appears to be.
When you do this you find that the crown appears to rotate about a point 2–3 mm below the gingival margin. If rocking the crown produces bubbles of saliva at the gingival margin this would be an indicator of a root fracture communicating with a periodontal pocket or the gingival crevice. No such bubbles are seen.
▪ Based on what you know so far, what are the likely causes?
Having excluded mobility caused by periodontitis and coronal bone loss, the two possibilities which remain the most likely are resorption or root fracture. The mobile tooth is rotating about a point just below the gingival margin so either process must affect the coronal part of the root.
Resorption of the apical half of the root would move the axis of rotation of the remaining tooth coronally. There would have to be extensive resorption to cause this degree of mobility and raise the axis of rotation so far. Resorption is a recognized complication of trauma to teeth and so this would be the most likely cause.
Root fracture is possible. No fracture was noted but the marked mobility would be consistent with the root fracture of the coronal part of the root. If there is a root fracture it would appear to be independent of the original trauma. Teeth which suffer coronal fractures do not usually suffer root fractures as well because most of the energy is absorbed by fracturing the crown. However, if a root fracture had been present for the last 4 years it might have triggered slow resorption, combining both possible causative factors.
An unsuspected lesion has destroyed the bone and/or the tooth root apically, leaving support only coronally; this is a remote possibility. The tooth would then be mobile about the remaining intact periodontal ligament. The commonest lesion to do this would be a radicular cyst arising on a nonvital tooth.
However this seems most unlikely as there is no expansion and the adjacent teeth are not displaced or mobile. A different lesion remains a remote possibility.
Investigations
▪ What investigations would you carry out? Why? What are the potential problems?
See Table 17.1.
| Test | Reason | Problems |
|---|---|---|
| Vitality test | To check the vitality of all four upper and lower incisors and canines (excluding any known root-filled teeth). Late loss of vitality is a complication of trauma and any one of these teeth could have periapical infection and be the cause of the bad taste. The vitality of the lateral incisor needs to be known, to plan treatment once the diagnosis is established. |
Electric pulp tests are notoriously difficult to perform on crowned teeth and the results must be interpreted with caution./> |
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