to the myopathy
Father estranged
Lives with his elderly grandparents, who are his primary care‐givers and are very protective of him
Requires specially arranged hospital transport to attend his appointments with both of his grandparents attending with him
Mild intellectual disability
Attends a public school
Oral Examination
Fair oral hygiene
Caries in #36 and #46
High‐arched/pointed (ogival) palate
Anterior open bite (Figure 1.3.2)
Radiological Examination
Orthopantomogram – confirmed the clinical findings (Figure 1.3.3)
Pattern of vertical mandibular growth (lateral cephalogram)
Structured Learning
1 What factors are considered important in assessing the risk of managing this patient?SocialTransport arrangements to attend dental appointmentsExcessive protectiveness by his guardians (the grandparents have already lost their daughter to the disease)MedicalMyotonic dystrophy type 1‐associated myotonia and multiorgan damage; muscle weakness, sleep disordersDiagnosis confirmed at birth is generally associated with a poor prognosisRisk resulting from cardiomyopathy and respiratory impairmentPosition in the dental chair compromised by the kyphoscoliosisFigure 1.3.1 Facial myopathy with severe open mouth.Figure 1.3.2 Anterior open bite.DentalRisk of aspiration during the dental procedureUnsupervised oral hygiene habitsFollow‐up difficulties due to social situation
2 The patient is taking prednisone at a dose of 20 mg/day. What are the implications of this when performing an invasive dental procedure?Delayed healingFigure 1.3.3 Lateral cephalogram showing a dolichocephalic growth pattern (relatively long skull).Increased risk of significant infectionAdrenal crisis may be triggered by surgical interventions due to chronic hypothalamic–pituitary–adrenal axis suppression – a corticosteroid supplementation protocol is required to prevent this (see Chapter 12.1)
3 What precautions should be undertaken in view of the patient's history of hypertrophic cardiomyopathy?Limit the administration of anaesthetics containing adrenaline and avoid intravascular injectionsSome cardiologists may disagree with international consensus guidelines, and hence recommend that these patients should receive antibiotic prophylaxis to prevent bacterial endocarditis if an invasive dental procedure is plannedA number of drugs, such as atenolol, can cause orthostatic hypotension
4 The patient's grandparents are insistent that an orthodontic appliance should be fitted as they feel that the palate is becoming more arched. What requirements should the patient satisfy before proceeding with orthodontic treatment?The oral hygiene should be extremely goodThe dentition should be stabilised, including restoration of #36 and #46The patient should be able to accept and tolerate both the intraoral and extraoral appliancesClose liaison with the medical team is required in order to evaluate the risk/benefit of proceeding, taking into account the progression of the muscular dystrophy
5 What type of appliances are recommended?In general, functional orthodontic devices are not recommended because the biological muscle forces are usually impairedDevices that may be prescribed for this patient include a palatal expander, multibracket appliances (for tooth alignment), a transpalatal bar with a stimulator/lingual pearl and/or a tongue guard and extraoral appliances such as a vertical traction chinguardHowever, due to the age of this patient, they may not be effective
6 What is the prognosis of the orthodontic treatment?The prognosis for the open bite and vertical mandibular growth is poorThe defect cannot be corrected in many patients, and the recurrence rate is high
7 Why are prevention and periodic follow‐up especially important for this patient?The patient will have increasing difficulty performing mechanical oral hygiene techniquesPhysiological mouth cleaning will worsen with timeThe bacterial load of the oral cavity can promote respiratory infectionsManaging the patient in the dental clinic will become increasingly complex
General Dental Considerations
Oral Findings
Difficulties in chewing, swallowing and phonation
Facial myopathy (hypotonia, dolichocephaly, open mouth) (Figure 1.3.4a)
Malocclusion with anterior open bite, posterior cross‐bite and tendency to Angle class III (Figure 1.3.4b)
Labial incompetence, mouth breathing, macroglossia and lingual protrusion
Tooth eruption delay
Agenesis, microdontia and hypoplasia, typically of the premolarsFigure 1.3.4 (a) Facial myopathy (hypotonia, dolichocephaly and open mouth). (b) Malocclusion with anterior open bite.
Accumulation of dental plaque and calculus, leading to gingivitis
Bone disorders of the temporomandibular joint, limited mouth opening and occasional joint subluxation
Oral manifestations secondary to drugs such as corticosteroids, antiarrhythmic agents, tricyclic antidepressants, benzodiazepines and calcium antagonists
Dental Management
The dental treatment plan will be determined by the muscle groups involved, the disease severity and the patient's life expectancy (Table 1.3.1)
Prevention is the key focus because the difficulties in performing dental procedures in these patients tend to worsen with time
Section II: Background Information and Guidelines
Definition
Muscular dystrophy consists of a heterogeneous group of hereditary diseases characterised by progressive weakness and impairment of skeletal muscles. These diseases are the main degenerative diseases in childhood. Duchenne muscular dystrophy is the most prevalent type, with 1 case per 3500 births, with no geographical or ethnic preferences.
Aetiopathogenesis
It has been suggested that muscular dystrophy is the result of a mutation in the genes that program critical proteins for muscle integrity, such as dystrophin
Dystrophin is found not only in skeletal muscle but also in the smooth and cardiac muscles, and also in the brain
The pattern of inheritance is variable:Sex‐linked muscular distrophies – Duchenne, Becker, Emery–DreifussAutosomal dominant – facioscapulohumeral, distal, ocular, oculopharyngealAutosomal recessive – limb‐girdle form
Clinical Presentation