Systemic Diseases and Their Effects on Jaws

Systemic Diseases Manifested in the Jaws

• Systemic diseases affect the entire body, and radiographic changes in the jaw reflect these generalized effects.
• Changes include alterations in bone size, shape, and density.
• The number, size, and orientation of trabeculae also change.
• Cortical structures' thickness and density are impacted.
• Overall bone density can increase or decrease.
• Systemic conditions affecting bone density typically do not affect mature teeth.
• Images of teeth can stand out from a radiolucent jaw, showcasing normal tooth density.

Changes to Teeth and Associated Structures

• Eruption can be accelerated or delayed.
• Hypoplasia is observed.
• Hypocalcification can occur.
• The lamina dura is sometimes lost.

Hyperparathyroidism

• An endocrine disorder featuring excessive parathyroid hormone (PTH).

• This mobilizes calcium from the skeleton and increases renal calcium reabsorption, leading to increased serum calcium levels.

• Two types exist: primary and secondary.

  • Primary results from a benign tumor.
  • Secondary arises in certain kidney diseases, compensating for hypocalcemia.

• Diagnosis involves elevated PTH levels, hypercalcemia, and sometimes elevated serum alkaline phosphatase.

• Age range is 30-60 years, more common in females.

• Clinical features include renal calculi, peptic ulcers, cognitive impairment, bone and joint pain, and potential tooth drifting/loss.

• Radiographic features include:

  • Teeth and associated structures: Loss of lamina dura, tapered appearance of teeth.
  • Jaws : Demineralization and thinning of cortical boundaries (particularly the inferior border of the mandible, the mandibular canal, and maxillary sinuses), overall decreased density and altered trabecular pattern (ground-glass appearance), presence of brown tumors with variable margins, causing cortical expansion.

• Multiple or solitary brown tumors (differentiate from central giant cell granuloma) can be observed.

• Other radiographic features include erosions in the phalanges, generalized demineralization, osteitis fibrosa cystica (single or multifocal, badly defined radiolucencies) calcifications in soft tissues (kidneys, joints) and a granular appearance of calvaria and jaw bones (“salt and pepper” skull).

Hypoparathyroidism

• True hypoparathyroidism: Damage to the gland, thyroid surgery.
• Pseudo hypoparathyroidism: Target tissue defect in responding to PTH.
• Clinical features: Tetany with carpopedal spasms, paresthesia in hands, feet, and mouth, neurologic changes, anxiety, depression, epilepsy, parkinsonism, and chorea.
• Radiographic features: Calcification of basal ganglia.
• Tooth features: Enamel hypoplasia, external root resorption, delayed eruption, and root dilaceration.

Hyperthyroidism

• Increased thyroxine levels. More common in females.
• Usually involves diffuse toxic goiter (Graves' disease), toxic nodular goiter, or adenoma.
• Signs include a high basal metabolic rate (BMR) leading to tachycardia, elevated blood pressure, irritability, and intolerance to heat.
• Children: Early tooth eruption and premature loss of primary teeth. Excessive bone resorption.
• Adults: Generalized decrease in bone density.

Hypothyroidism

• Low thyroxine levels.
• Clinical features (in children/adults): Retarded/deteriorated mental/physical development, delayed closure of fontanelles and epiphyses, delay in base of skull ossification, relatively small mandible/maxilla, short roots, thin lamina dura, delayed eruption/exfoliation of teeth, or dull expressionless face, periorbital edema, sparse hairs, doughy skin.
• Jaw and tooth features: Periodontal disease, potential loss of teeth, enlarged tongue with potential spacing of teeth, and external root resorption

Osteopenia

• An imbalance between bone deposition and resorption resulting in reduced bone formation.
• Histologically, bone may appear normal.
• Architecture of trabeculae and size/thickness change.
• Clinical features: Asymptomatic early on, later, bone pain may be a symptom. Most individuals at risk are postmenopausal women.
• Radiographic features: Overall reduction in bone density, thinning of cortical boundaries, sometimes a thinner lamina dura, reduction in trabeculae number/size.
• Management includes administration of estrogen, calcium, and vitamin D supplements after menopause, weight-bearing exercise, and oral antiresorptive medications.

Rickets and Osteomalacia

• Nutritional deficiencies lead to impaired bone mineralization.
• Rickets occurs in children.
• Osteomalacia impacts adults.
• Clinical features of Rickets: tetany or convulsions in first 6 months of life, craniotabes, softening of parietal bones, short stature, bowing of legs, swelling of wrists and ankles, delayed tooth development/eruption, enamel/dentin hypocalcification.
• Clinical features of Osteomalacia: Bone pain, muscle weakness, "penguin" gait, tetany, and green stick fractures.
• Radiographic features of Rickets: Thinning/missing cortical structures, inferior border, mandibular canal, and developing teeth, and overall appearance of radiolucency.
• Radiographic features of Osteomalacia: Thin cortex, pseudofractures (commonly in ribs, pelvis, and weight-bearing bones, less often mandible), an overall radiolucent appearance, and sparse trabeculae.

Osteopetrosis

• Increased bone density, due in infants to progressive loss of marrow and its products; in adults, more benign and may be asymptomatic or present with bone pain, cranial nerve palsies from neural compression.
• Radiographic features in infants: Very high density, may be fatal in early life, narrowing of bony canals may result in hydrocephalus, blindness, deafness, vestibular nerve dysfunction, and facial nerve paralysis.
• Radiographic features in adults: May show thicker cortical boundaries and lamina dura, may not show internal structure or roots of teeth, the interface between cortical and cancellous bone may be obscured, the inferior alveolar canal may be more prominent, and the bone may appear underexposed.

Sickle Cell Anemia

• A hereditary blood disorder with abnormal hemoglobin and sickle-shaped red blood cells.
• Clinical features: Mild attacks (fatigue, weakness, shortness of breath, muscle/joint pain); severe exacerbations (sickle cell crises, severe abdominal/muscle/joint pain, high temperature, and circulatory collapse).
• Jaw features: General osteopenia, thinning of cortical plates, and coarser trabeculation in the alveolar bone.
• Other radiographic features: Thinning of cancellous trabeculae caused by bone marrow hyperplasia and, potentially, vertebral bodies, long bones, skull, and jaws; often includes widening of the diploic space of the skull, thinning of the inner and outer tables of the skull, and a descriptive pattern called a “hair-on-end appearance”. Osteomyelitis is possible if infections occur.

Thalassemia

• Cooly's anemia, Mediterranean anemia.
• Clinical features in infants: Severely impacts survival, causes short survival time. Clinical features in adults: milder form, prominent cheekbones, protruded premaxilla, a “rodent-like” face.
• Radiographic features: Widened diploic space of the skull, thinning of the inner and outer tables of the skull, a “hair-on-end appearance” is sometimes descriptive. Also, generalized lucency in long bones; occasional fractures are also possible.
• Jaw features: large marrow spaces, course trabeculae, thin lamina dura, short roots, potential for a prominent premaxilla leading to malocclusion, and large, coarse trabeculae.