Foetal hypothyroidism, which can cause cretinism, has disappeared from the US and Europe thanks to iodine administration campaigns
However, cretinism still exists in remote rural areas of many countries, and it is estimated that the condition affects 2 million children annually
The belief that iodine deficiency disorders are hereditary tends to be prevalent in societies where familial goitre is common and where the rate of endogamy is high; this situation makes prophylactic dietary interventions seem useless and wasteful
Water fluoridation, in regions where it is technically feasible and culturally acceptable, yields proven benefits in terms of public health, including preventing caries; however, it has been suggested that water fluoridation could cause hypothyroidism as fluoride and iodine have an antagonistic relationship
Recommended Reading
1 Chaker, L., Bianco, A.C., Jonklaas, J., and Peeters, R.P. (2017). Hypothyroidism. Lancet 390: 1550–1562.
2 Chandna, S. and Bathla, M. (2011). Oral manifestations of thyroid disorders and its management. Indian J. Endocrinol. Metab. 15: S113–S116.
3 Huber, M.A. and Terézhalmy, G.T. (2008). Risk stratification and dental management of the patient with thyroid dysfunction. Quintessence Int. 39: 139–150.
4 Little, J.W. (2006). Thyroid disorders. Part II: hypothyroidism and thyroiditis. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 102: 148–153.
5 Pinto, A. and Glick, M. (2002). Management of patients with thyroid disease: oral health considerations. J. Am. Dent. Assoc. 133: 849–858.
6 Venkatesh Babu, N.S. and Patel, P.B. (2016). Oral health status of children suffering from thyroid disorders. J. Indian Soc. Pedod. Prev. Dent. 34: 139–144.
7 Wémeau, J.L., Do Cao, C., and Ladsous, M. (2017). Oral and dental expression of thyroid diseases. Presse Med. 46: 864–868.
5.3 Hyperthyroidism
Section I: Clinical Scenario and Dental Considerations
Clinical Scenario
A 54‐year‐old female presents to you for a second opinion. She is unhappy about the appearance of her teeth which she feels look rough and discoloured.
Medical History
Graves disease/hyperthyroidism diagnosed 4 weeks ago
Atrial fibrillation – detected at the same time as the hyperthyroidism
Gastro‐oesophageal reflux disease
Medications
Propylthiouracil
Dabigatran
Omeprazole
Dental History
Irregular attender; only attends if there are dental problems
Good co‐operation; history of multiple fillings and dental extractions
Brushes twice a day using hard bristle toothbrush to remove the staining
Highly cariogenic diet, including consumption of tea with 3 spoons of sugar 4–6 times a day
Likes to chew/suck on citrus fruits
Also began eating black grapes several times a day since commencing propylthiouracil as she found this helpful with her symptoms of nausea
Social History
Widowed housewife
Lives with eldest daughter who works as a secondary school teacher and is responsible for transportation
No alcohol or tobacco consumption
Oral Examination
Mild goitre (Figure 5.3.1)
Generalised pitted hypoplastic enamel and staining present on buccal surfaces of teeth (Figure 5.3.2)Figure 5.3.1 Mild goitre (anterior and lateral view).Figure 5.3.2 Pitted hypoplastic enamel and staining present on buccal surfaces of the anterior teeth.Figure 5.3.3 Generalised moderate to severe tooth surface loss on the palatal and occlusal surfaces of the maxillary dentition.
Generalised moderate to several tooth surface loss (erosion and attrition) with possible pulpal involvement of #11 (Figure 5.3.3)
Temporary filling in situ #15
Caries in teeth #17, #14 and #45
Supragingival calculus present on the lingual surfaces of the lower incisors
Generalised gingival recession
Missing (due to extraction) teeth #16, #24, #36 and #37
Radiological Examination
Orthopantomogram and long cone periapical radiograph #15 undertaken (Figures 5.3.4 and 5.3.5)
Generalised bone loss (~60–70%)
Patchy medullary radiolucency suggestive of osteopenia/osteoporosis
Periapical radiolucency associated with the apex of tooth #15
Structured Learning
1 What is ‘goitre’ and how does it affect your dental planning?Goitre is an enlarged thyroid gland which causes a swelling in the front of the neck that moves up and down on swallowingThyroid function can be normal (euthyroid), which requires regular monitoring, or hyperactive (hyperthyroid)/hypoactive (hypothyroid), which both require active treatmentThe impact on dental planning is dependent on any associated abnormal thyroid function and complications associated with the enlargement (e.g. respiratory obstruction, cough, voice changes, dyspnoea, tracheal deviation or dysphagia)
2 The patient believes that the appearance of her teeth has worsened due to hyperthyroidism. Is she correct?No – she has enamel pitting; this is a form of enamel hypoplasia which would have been caused at the developmental enamel matrix formation stage of the teethFigure 5.3.4 Orthopantomogram demonstrating patchy medullary radiolucency suggestive of osteopenia/osteoporosis.Figure 5.3.5 Long cone periapical radiograph demonstrating periapical radiolucency associated with the apex of tooth #15.Defects are divided into 4 categories: pit‐form, plane‐form, linear‐form, and localised enamel hypoplasiaCauses may include nutritional factors (malnutrition), some diseases (such as undiagnosed and untreated coeliac disease), hypocalcaemia, infection, abnormalities in amelogenesisSecondary staining (likely to be linked to increased daily consumption of black grapes) may have made the pitting more noticeable
3 What