Unfortunately, there is no one method which a dentist can use to decide whether to treat, extract or keep under observation..
Dentists therefore use variation of different factors which they then use in combination to decide whether a tooth is so compromised that it should be extracted. It goes without saying that sometimes a tooth is often better extracted because alveolar bone will be preserved rather than allowing the periodontal disease to destroy further little remaining alveolar bone.
An important factor is therefor the amount of bone loss to be quantified. This is carried out using a periapical radiograph and initially measuring the distance from the alveolar bone crest to the apex. The other measurement is the distance from 2mm below the cement-enamel junction to the apex. The percentage bone remaining is the 1st reading divided by the 2nd reading times 100. It is accepted that bone loss less than 30% is fine and tooth can be preserved. If the bone loss is between 30 to 60%, the tooth is compromised and other factors will also need to be factored in. Any bone lost more than 60% will render it useless.
The next important factor to look at is the attachment loss. Attachment loss is the sum of the pocket depth measurement and the amount of gum recession as measured from the cement enamel junction of the tooth. You also need to consider if the probing into the pocket causes any bleeding or not. Bleeding indicates active disease.
Pocket depth measurements of 5 mm or less are very amenable to preservation. Pocket depth measurements of between 5 mm to 7 mm render a tooth with questionable prognosis but in some cases can still be preserved. Trying to leave a pocket that the measurement is of more than 7 mm is unrealistic and should be extracted.
On posterior molar teeth, the amount of furcation involvement also has a bearing on the tooth prognosis.
The occlusion should be favourable and the patient not suffering from any parafunction habits for a tooth to have a better prognosis.
The condition of the crown of the tooth should be taken into account. But at the same time if it has extensive caries, it will usually render the tooth useless.
Strategic value of a tooth should be considered because some teeth have a greater strategic value than other teeth.A good example is where there is a last tooth in the arch and this is required for denture stability.
A patient’s age should also be looked out for including their general health. In terms of general health,the most common condition which will compromise a patient is that of diabetes. Is it because diabetes compromises the immune system which then also compromises the patient respond to treatment but also the amount of destruction that occurs for the same amount of plaque.
Of ultimate importance is the patient’s oral hygiene and their motivation. We have all seen patients which have teeth which were really compromised but they have lasted longer than expected simply because the patient has had good motivation and meticulous good oral hygiene.
Finally, a patients finance also needs to be discussed. We have all seen patients who have spent up vastly more money in keeping a compromised tooth as opposed to having the tooth extracted and even having an expensive replacement. It is important to also bear in mind that the advantage of keeping your dentition is that a natural tooth has bio receptors which no other form of tooth replacement can have.
A tooth with a 5 year prognosis is considered to be doomed. A tooth with a
5-10 year prognosis is considered a guarded one. Over 10 years is acceptable.
Once all the parameters have been considered, a decision has to be made as to what you think a tooth is likely to last for. This can be divided into 3 categories. If a tooth is considered to last less than 5-years, it is considered to have a hopeless prognosis. A tooth which is set to last for between 5-years and 10 years, is said to have guarded or reduced prognosis. If a tooth is deemed to last more than 10 years it is considered to have a reasonably good prognosis. More than 20 years and it is said to last for life.
Dr Muzzafar Zaman 