33 Tooth discoloration, hypomineralization and hypoplasia
What specific questions do you need to ask his mother with regard to potential causes of discoloration?
The health of Simon’s mother during her pregnancy and Simon’s health during the birth and delivery are important when considering the condition of the first permanent molars (FPMs). The FPMs were the only permanent teeth that had started to mineralize before birth (≈ eighth month of pregnancy). Conditions that may suggest some fetal distress and dysmineralization may be: raised maternal blood pressure; early admission to hospital; premature delivery; prolonged delivery; assisted delivery, e.g. forceps or ventouse, emergency caesarean section; admission to the special care baby unit (SCBU).
These may result in a ‘chronological hypoplasia’ affecting those parts of the teeth that were mineralizing at the time of the illness. Although ‘chronological hypoplasia’ usually involves some failure of development of enamel matrix giving obvious lines or ridges on the teeth, there may be milder forms that can only be felt with a probe and that present for care because they attract extrinsic stain.
Tetracycline staining should not occur now in children who have been brought up in developed countries. It is still common in children from developing countries where tetracycline is still used because it is a very effective, cheap, broad-spectrum antibiotic. The only children who may still be affected in developed countries are those with cystic fibrosis who have developed multiple drug resistances as a result of recurrent respiratory infection.
Simon was born with primary biliary atresia. This resulted in progressive liver failure, increasing levels of circulating bilirubin and eventually a liver transplant at the age of 2.5 years. All the permanent teeth developing prior to the transplantation will have intrinsic discoloration as a result of the high circulating bilirubin. The primary dentition will be affected to a lesser extent as a result of staining in secondary dentine. He has gingival overgrowth as a result of immunosuppressive treatment with ciclosporin. Figure 33.2 shows a photograph taken later at the age of 13. The newly erupted second permanent molars are entirely normal. These teeth started mineralizing about the age of 3 when there was a functioning new liver and normal levels of bilirubin.
A full history from birth including areas that the child has lived in, fluoride supplementation and brushing habits is required. Fluorosis will produce a systemic or chronological distribution affecting the teeth that were forming when excess fluoride was taken.