Discoloured teeth Flashcards
How does chlorhexidine discolour teeth?
It is now believed that when chlorhexidine denatures the pellicle (protein film) on teeth to
create free radicals, that the latter reacts with iron to form coloured sulphur containing complexes.
Extrinsic staining can usually be effectively removed by ultrasonic scaling and
polishing.
What is pulpal haemhorrhage?
Intrinsic staining as a consequence of trauma that results in haemorrhage of the
pulp, has been discussed earlier.
Liberated haemoglobin pigment is progressively converted to biliverdin (a greenish colour) then to bilirubin (yellow colour) and this again to hemosiderin (golden brown). These pigments diffuse into dentinal tubules and discolour the tooth with gradually changing shades of these different hues.
What is internalised discolouration?
Dentine can be discoloured by penetration of stains from previous extrinsic
staining. This usually develops as a consequence of poorly formed or absent
enamel. Internalised discolouration might also originate from acquired defects
such as tooth wear, caries and gingival recession.
How does tetracycline discolour teeth?
Use of tetracycline during the development of teeth could cause discolouration.
These drugs appear to form complexes with calcium ions on the surface of hydroxyapetite crystals and dentine is more affected than enamel.
Different forms of tetracycline will produce different colours and UV light causes
a yellow fluorescence of affected teeth.
How can fluoride stain teeth?
Excessively high levels of fluorine in drinking water or over supplementation can
change the appearance of enamel. The discolouration is probably caused by internalised discolouration from pigment that penetrates abnormal enamel.
How does ageing change tooth colour?
In very young teeth with very thin tooth walls, the pulp might shine through. This
pinkish appearance gradually disappears as dentine thickens and the tooth becomes whiter. With further deposition of secondary dentine, the tooth will gradually become darker and more ivory coloured.
What is dental sclerosis?
With a gradual occlusion of dental tubules tooth develops almost glasslike appearance and this is frequently seen in older cats.
How does pulpitis change tooth colour?
Pulpal blood vessels compromised by inflammation could cause bleeding that
causes intrinsic stains in the same way that haemorrhage caused by trauma
does.
Discuss how caries discolour teeth?
Carious lesions develop as a consequence of the bacterial breakdown of carbohydrate rich residues on the tooth surface, to produce acids. These acids gradually de-mineralise enamel and dentine and occur mostly on the flat occlusal
surfaces of the molar teeth in dogs.
The initial damage happens in fissures on the occlusal surface. The initial lesion
that penetrates the enamel, might be quite small but the process accelerates
once the less mineralised dentine is reached. The demineralisation of the dentine undermines the overlying enamel and the unsupported enamel fractures reveal a much larger crater.
Exposure of the dentine would cause pain and ingress of chemical irritants to
the pulp will cause pulpitis and therefore more severe pain.
Early lesions can be restored after removal of all the affected dentine and
enamel. With lesions that penetrate to very close to the pulp chamber, irreversible pulpitis should be assumed, and if these teeth are to be saved root canal
treatment is indicated. Extraction is always a good option once caries has developed to this stage.
What are GV Black’s classification of Caries?
Class I occlusal areas and buccal or lingual pits
Class II posterior interproximal
Class III anterior interproximal
Class IV anterior interproximal including incisal corner
Class V cervical or gingival at facial or lingual aspects
Class VI cuspal tips
What is Chronic Alveolar Osteitis?
Buccal bone expansion is not uncommon, especially in older cats. It occurs at
different teeth but is most obvious at the maxillary canine teeth. This expansion
develops by medullary fibrosis and proliferation of woven bone, with a thin rim
of sclerotic bone evident at the periphery. This expansion of this bone causes
thinning of the overlying soft tissue.
Extraction is usually indicated because of the underlying condition. Elevation of
mucogingival flaps are challenging because of the thin tissue. Alveoloplasty
should be considered to facilitate tension-free closure. Extra care should be
taken to not remove too much of this buccal bone as this might cause impingement of the mandibular canines on the upper lip in this area.
