Pediatric Abnormalities: Free INBDE Prep Course
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UNDERSTANDING PUBLIC HEALTH
TOOTH ANOMALIES
Natal teeth are deciduous teeth that are present when a baby is born and is seen in 1 in 2000-3000 births. Neonatal teeth appear within the first 30 days. They are most likely deciduous mandibular incisors. If the natal and neonatal teeth are mobile (underdeveloped roots) they can be a choking hazard, and often interfere with feeding causing trauma to the soft tissue on the ventral surface of the tongue (Riga-Fede disease). These teeth are best removed.
About 3% of the population will present with an increased number of teeth, with males twice as likely to be affected. The most common supernumerary is the mesiodens, found between the central incisors, often positioned palatally. Supernumerary teeth can look like regular teeth but are often conical, tuberculate or molar shaped. Removal is the most common treatment. Apert’s syndrome, Cleidocranial dysplasia, cleft lip and palate, Crouzon’s syndrome, Down syndrome, Gardener’s syndrome, Hallermann-Streiff syndrome, Oral-facial-digital syndrome type 1 and Sturge-Weber syndrome are all associated with supernumerary teeth.
There can also be too few teeth, seen in 1.5-10% of patients (not including third molars). The most commonly missing teeth are the third molars, second premolars, and lateral incisors (in that order). Achondroplasia, cleft lip and palate, Crouzon’s, Chondroectodermal dysplasia, Down syndrome, Ectodermal dysplasia, Hallermann-Streiff syndrome, Incontinentia pigmenti, Oral-facial-digital syndrome type 1, and Rieger’s syndrome are associated with congenitally missing teeth.
- Oligodontia – A term for the absence of one or more teeth (not including third molars).
- Hypodontia – A term for the absence of 6 or more teeth. Usually part of syndrome.
- Anodontia – All teeth are missing. This is very rare. Usually associated with Ectodermal Dysplasia.
Differences in size are most often seen in patients presenting with a peg lateral.
- Macrodontia is less common and seen in facial hemihypertrophy and otodental syndrome.
- Microdontia refers to the teeth that are smaller than they should be, and can be associated with ectodermal dysplasia, chondroectodermal dysplasia, hemifacial microsomia, and Down syndrome.
- Fusion refers to the union of two teeth and is more common in the anterior deciduous dentition. These teeth have two pulp chambers and two canals, and appear as a macrodont (large crown). The giveaway (when compared to gemination) is the absence of one tooth in the headcount. In other words, a macrodont tooth in a lower deciduous arch where you can only count 9 teeth suggests fusion.
- Concrescence is a form of fusion where there is cementum contact occurring after root formation is completed. It is usually seen as a result of trauma.
- Gemination occurs when a single tooth bud ‘splits’ into a bifid crown. It is also more common in primary teeth and presents with a single shared pulp chamber and single canal. The tooth count will be normal.
Differences in tooth shape is common:
- An extra cusp/part of a cusp is termed dens evaginatus. If found on an incisor it is called a talon cusp. This protrusion contains all parts of the tooth including pulpal tissue so care should be taken.
- If there is an invagination of dental material it is termed dens invaginatus/dens in dente. The adult lateral incisors are the most commonly affected, and the defect can be so deep as to cause inevitable decay and pulpal problems. If located early after eruption a fissure sealant may prevent future problems.
- Taurodontism is characterized by vertically long pulp chambers and short roots.
- Dilaceration refers to a bend or twist in the tooth or root, usually seen in an adult tooth after trauma to the baby tooth. A dilacerated tooth can prevent normal development and eruption (often become impacted).
Difference in color can be caused by a number of conditions or medications:
- Porphyria – purplish brown teeth.
- Cystic fibrosis – yellowish-gray to dark brown teeth. May be related to tetracycline use, since they suffer from chronic respiratory infections.
- Erythroblastosis Fetalis – blue-green primary teeth caused by the excessive destruction of erythrocytes.
- Tetracycline – yellow to brown to gray to black, staining permanent teeth that have not completed formation.
- Amelogenesis imperfecta – white opaque to yellow to brown.
- Dentinogenesis imperfecta – opalescent teeth.
- Hyperbilirubinemia – jaundice like yellow-green tint.
Ankylosed Primary Molars
Seen in 1-4% of patients, ankylosis is more common in Caucasians and appears to be associated with congenitally missing permanent premolars. The neighboring teeth erupt but leave the ankylosed tooth infra-occluded. The difference in height increases with age. There is usually no mobility even when root resorption is present, and the tooth sounds different to percussion. Treatment isn’t always necessary, but the tooth may need to be removed to allow the adult tooth through (if it’s there). Consider space maintenance if appropriate. Building up the lost height with composite or a stainless steel crown is a viable treatment option.
Wear and Tear
- Attrition is the physiological wearing away of tooth structure caused by tooth on tooth contact creating wear facets. Attrition increases with age and is more pronounced in bruxers.
- Abrasion is caused by an external mechanical force. Toothbrush abrasion is commonly seen as a V shaped notch on the dentin surface just apical to the cemento-enamel junction (CEJ). Ill fitting dental appliances, nail biting, chewing tobacco, lip/tongue piercings, and abrasive toothpastes can all cause tooth abrasion.
- Erosion is tooth loss from a chemical source. Chronic vomiting habits (anorexia nervosa, reflux etc.) often cause damage to the lingual surfaces of teeth. Frequent consumption of acidic foods or drinks are a common cause. Often the occlusal surface of teeth appear “scooped out” due to the difference in solubility of enamel and dentin. Eroded surfaces can leave restorations “floating” since they don’t erode. Erosion can worsen/speed up loss due to attrition and abrasion.
CHANGES IN MICROSTRUCTURE
Enamel hypoplasia refers to a quantity deficiency of enamel, while the quality of enamel might remain normal. Many things can disrupt the proper formation of enamel by disrupting the maturation or function of ameloblasts, including systemic diseases, infection, fevers, fluorosis from increased systemic absorption of fluoride, nutritional deficiencies (Vit A, C, D, Calcium, phosphate), radiation, chemotherapy, Rubella, and lead poisoning. The teeth may appear chalky and yellow to brown in color. Conditions like amelogenesis imperfecta, nephrotic syndrome, cleft lip and palate, and Sturge-Weber syndrome are also linked with enamel hypoplasia. Syphilis produces a classic pattern of hypoplasia with Hutchinson incisors and mulberry molars.
Enamel hypocalcification refers to a quality deficiency and can be seen resulting from the same environmental and genetic conditions as above. The quantity of enamel can be normal but formed from a defective matrix. Enamel hypocalcification is associated with hypoparathyroidism.
Amelogenesis imperfecta (AI) is a hereditary form of enamel hypoplasia and/or hypocalcification that has an incidence of around 1 in 14,000 births and affects the enamel only. Patients present with normal dentin, pulps and roots. It is a defect of the histodifferentiation stage of dental development. The hypoplastic variation of amelogenesis imperfecta causes the formation of thin enamel with the teeth appearing yellow to brown (dentin visible through the thin enamel). Hypomaturation and hypocalcification variants of amelogenesis imperfecta may present with normal enamel thickness, but poor quality that is easily damaged. These teeth are susceptible to decay. Treatment options vary according to the extent of the damage, but full coverage may be required.
Dentinogenesis imperfecta is more common at 1 in 8,000 births and is also a defect of the histodifferentiation stage of dental development. Improper predentin matrix production results in amorphous, atubular, under-mineralized dentin formation that can affect both the deciduous and adult teeth. There is often a visible color difference, from purple to reddish brown to gray and opalescent. The roots are not normal, often slender, and pulp chambers often small or completely obliterated. The crowns are bulbous and the roots short. The enamel can be of proper quality but is easily separated from the compromised dentin. Treatment options vary according to the extent of the damage, but full coverage may be required.
- Type I Dentinogenesis imperfecta is associated with osteogenesis imperfecta (blue sclera, fragile bones, hearing loss).
- Type II Dentinogenesis imperfectais the most common form.
- Type III Dentinogenesis imperfecta (Brandywine Type) sees multiple pulpal exposures in the primary dentition.
Dentin dysplasia (DD) is a rare genetic developmental disorder seen in approximately 1 in every 100,000 patients. It affects both the adult and deciduous teeth and is characterized by the presence of normal enamel but atypical dentin with abnormal pulpal morphology. In Shields type 1 the crown anatomy is normal, visually they appear like Dentinogenesis imperfecta, but with short, pointed roots, absent pulp chambers and multiple periapical radiolucencies. In Shields type 2 the baby teeth appear like Dentinogenesis imperfecta, and the permanent teeth have normal color, pulp stones and thistle tube shaped pulp chambers with no periapical radiolucencies.
Regional odontodysplasia, Vitamin D–resistant rickets, Hypoparathyroidism, and Pseudohypoparathyroidism can also affect dentin formation.
DEVELOPMENTAL ABNORMALITIES
Hemangiomas are very common vascular benign tumors seen in infants, most often girls. They are not birthmarks, and appear within a week or two after birth. Hemangiomas are common on the lips, tongue, buccal mucosa, and skin, appearing as a deep red or bluish red raised (or flat) lesion. Most do not require treatment and will spontaneously involute, others are surgically removed.
Achondroplasia is a form of short limb dwarfism that’s seen with equal prevalence in males and females, characterized by a large head and short arms and legs. A patient with achondroplasia will have deficient cranial base growth, a small maxilla, underdeveloped mandible, and will typically present with a Class III malocclusion. The teeth are slow to exfoliate and erupt.
Pituitary Dwarfism causes the delay of eruption and shedding of primary teeth. The crowns and roots of teeth appear smaller, the dental arch is often smaller as well. The mandible is underdeveloped.
Gigantism is characterized by excessive growth caused by oversecretion of growth hormone from the somatotropic cells of the anterior pituitary gland. Everything is enlarged, the tongue, the mandible, even the roots of the teeth.
Cretinism is a form of severe hypothyroidism (thyroxine deficiency) restricting both physical and mental development. Patients have dwarf-like characteristics with curved spines, limbs aren’t proportional, the tongue is large, the mandible is underdeveloped and the maxilla is overdeveloped. Eruption is delayed and the primary teeth may be retained. In adults, hypothyroidism is termed myxedema.
Treacher Collins Syndrome, also known as mandibulofacial dysostosis, results from a mutation of the 5q32 gene. Patients present with down slanting eyes, notched lower eyelids, an underdeveloped midface and diminutive ears.
Crouzon syndrome is another uncommon craniofacial disorder characterized by the early fusion of the baby’s skull (craniosynostosis) and deformed facial features. It presents with maxillary hypoplasia, narrow dental arches and crowded teeth, a short upper lip and head, and widely spaced eyes with exophthalmos (protruding eyes). A crossbite is a common feature.
Ectodermal dysplasia is a hereditary condition associated with the abnormal development of multiple structures originating from the ectoderm, including the skin, hair, nails, teeth, and sweat glands. The x-linked (males only) anhidrotic ectodermal dysplasia is the most common variant. Anodontia or oligodontia is possible, and conical shaped teeth are often seen. Atrophic skin, defective hair and hypoplastic sweat glands (lack of perspiration) are distinctive features of ectodermal dysplasia.
Cleidocranial dysostosis (dysplasia) is an inherited disorder of bony development that presents with incompletely formed clavicles, a characteristic facial appearance, and dental abnormalities (supernumerary teeth, missing teeth, peg-shaped teeth, delayed eruption). “Stranger Things” star Gaten Matarazzo is a famous case of cleidocranial dysplasia.
Down Syndrome is a congenital defect caused by a chromosomal abnormality (trisomy 21) leading to patients with delayed physical and mental development, delayed eruption of teeth, a flat broad face, slanting eyes, short nose, small low set ears, and short stature. Heart defects are common. They have a lower caries risk but periodontal disease is more prevalent.
Apert’s syndrome falls under the cranial-limb anomaly category, characterized by malformations of the hands and feet (fused fingers and toes), midface and skull. The sutures of the skull fuse early causing a maxillary retrognathia. It may present with supernumerary teeth, disruption of normal eruption, severe crowding, and a Class III malocclusion.
Autism is a common and complex developmental disability that presents as a spectrum of clinical observations. It is usually recognized in the first 3 years of life and is three times as likely in boys, often genetically linked to the father. “Mild autism” can be relatively easy to manage in a dental setting, but more severe can see an acute sensitivity to certain sensory stimuli (taste, smell, light, sound etc) and communication can be a problem.
Cystic fibrosis is an inherited exocrine gland disorder affecting 1 in 3000 newborns and is more common in caucasians. A mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) protein causes abnormal secretions in the lungs, pancreas, liver, kidneys and intestines. Faulty sodium and chloride channels affect the sweat glands and cause the skin to taste salty. Elevated Na and Cl in the sweat confirms the diagnosis. Patients with cystic fibrosis often present with coughing and wheezing due to a chronic susceptibility to respiratory infections and pneumonia. They exhibit poor weight gain and bulky foul smelling stools due to intestinal changes. The teeth may be darker in appearance (tetracycline use?) and development delayed. The salivary glands may become dysfunctional leading to xerostomia.
Porphyria are a group of inherited disorders affecting heme pigment formation, resulting in a buildup of natural chemicals that produce porphyrins in your body. There is no known cure. Porphyria can result in tooth discoloration (purplish brown teeth). Patients may suffer from photodermatitis (light sensitivity), neuropsychiatric complaints, and visceral complaints. They may have red urine.
Inclusion Cysts
Inclusion cysts are common, seen in about 75% of infants. The three most common inclusion cysts are:
- Epstein’s pearls – entrapped epithelium along the median palatal raphe.
- Bohn’s nodules – ectopic mucous glands on the labial and lingual alveolar surfaces.
- Dental lamina cysts – remnants of the dental lamina along the crest of the alveolus.
Facial Clefts
Cleft lip (CL) and Cleft palate (CP) accounts for half of all facial cleft defects, CL is more common in males and more often seen unilaterally on the left side. CP is more common in females. The fusion of the lip, alveolar ridge, and palate can be involved, affecting speech, swallowing and aesthetics. CL & CP can occur unilaterally, often due to a birth defect that isn’t associated with a syndrome, or bilaterally, linked to Stickler’s, Vander Woude’s, and DiGeorge syndrome. There are four classes of CL:
- Class I: Unilateral notching of vermillion not extending to lip.
- Class II – Class I but involving the lip, not to the floor of the nose.
- Class III – Class II but extending into the floor of the nose.
- Class IV – Any bilateral cleft of the lip.
There are four classes of CP:
- Class I– only the soft palate is involved.
- Class II – the soft palate and hard palate are involved, but not the alveolar processes.
- Class III – the soft palate, hard palate and alveolar process on one side of the premaxilla.
- Class IV – the soft palate, hard palate and alveolar process on both sides of the premaxilla.
CL is repaired 10 weeks after birth, CP 9-18 months after birth. CL is reviewed around age 5. Then another pharyngeal flap surgery or pharyngoplasty 3-5 years later, alveolar reconstruction at 6-9 years (based on dental development), and orthognathic surgery at 14-18 years (14-16 for girls, 16-18 for boys).
Pierre Robin syndrome is a congenital defect characterized by facial abnormalities, presenting with Mitral valve prolapse, micrognathia, glossoptosis (downwardly displaced tongue), and obstruction of the upper airway. A wide, U-shaped cleft palate is commonly seen. PRS is not merely a syndrome, but a sequence—a series of specific developmental malformations which can be attributed to a single cause, a collagen gene 2A1 mutation.
