Dents and other abnormalities in the shape of the skull can be caused by congenital disorders, such as craniosynostosis or Gorham's disease, vitamin A toxicity, trauma to the head and other conditions. Dent Neurologic Institute details the condition called craniosynostosis, or craniostenosis, in which an infant's sutures between the bony plates of the skull prematurely close, frequently resulting in an oddly-shaped skull.
Though rare, Gorham's disease, an idopathic disorder that replaces one or several bones with vascular and connective tissue, can sometimes cause a misshapen skull, according to The Lancet.
According to Healthline, Vitamin A toxicity, or hypervitaminosis A, often causes bone pain and swelling of the bones in adults and softening of the skull bone or bulging of the soft fontanelle at the top of the skull in children. Vitamin A toxicity results from an excess of vitamin A in the body.
Trauma to the head, such as being struck by an object, can cause a skull fracture. Harvard Health explains that a fracture is a crack in one of the skull's bones. Sometimes, the skull bone is dented inward; which is called a depressed skull fracture. In this condition, fragments of shattered bone press against the brain's surface.