1. Protecting All Children’s Teeth
Dental Development

2. Introduction
It is important for child health providers to understand normal dental
development so that proper anticipatory guidance can be provided to
families, deviations from normal can be recognized, and accurate decisions
about intervention can be made.

3. Learner Objectives
Upon completion of this presentation, participants will be able to:
Recall the typical pattern and timing of tooth eruption.
Describe instances in which a practitioner should be concerned about eruption and refer for evaluation.
List medical causes of premature and delayed tooth exfoliation.
State at least 4 common etiologies of tooth discoloration.
Correctly identify symptoms associated with teething and summarize proper teething management.
Outline common symptoms and causes of malocclusion.

4. Normal Development Oral structures begin to form during the third
and fourth weeks of embryonic development. The teeth begin to develop around the sixth
week of fetal life. Development continues throughout fetal life
and beyond.
Notes:
Germ cells from the ectoderm, mesoderm, and endoderm all contribute to tooth formation.
Tooth development is divided into the following stages: the bud, the cap, the bell, and crown (maturation).
An insult can happen at any or multiple points in the development process and lead to abnormal outcomes. For example, a febrile illness can cause enamel hypoplasia and excess fluoride ingestion can result in fluorosis.

5. Tooth Eruption: Primary Teeth
Primary teeth begin to erupt around 6 months of age.
Eruption is completed by 24 to 36 months.
Delays of more than 12 months merit further dental evaluation.
Notes:
The order of eruption of the 20 primary and 32 permanent teeth is fairly predictable, although the timing may vary.
Girls’ teeth usually erupt slightly earlier than boys.
Delays in tooth eruption can be familial.

6. Tooth Eruption: Primary Teeth
Eruption is usually symmetrical (lower teeth before upper) in the following pattern for primary teeth:
Central incisors
Lateral incisors
First molars
Canines
Second molars
Exfoliation often follows a similar pattern.
Notes:
A helpful mnemonic to remember the timing of primary eruption is the 7+4 rule. At 7 months of age, children should have their first teeth; at 11 months (4 months later), they should have 4 teeth. This pattern continues as follows: 15 months = 8 teeth; 19 months = 12 teeth; 23 months = 16 teeth; 27 months = 20 teeth.
Glossary:
Exfoliation: The shedding of a superficial layer of a tooth.

7. Tooth Eruption: Permanent Teeth
Eruption for the permanent teeth is similar to that of the primary teeth.
Eruption of the permanent teeth begins between 5 and 7 years of age and usually finishes by 13 to 14 years.

8. Tooth Eruption: Permanent Teeth
The typical pattern for the eruption of permanent teeth is:
Central incisors
Lateral incisors
First molars
Premolars
Canines
Second molars
Third molars (wisdom teeth)
Notes:
Not everyone develops or erupts third molars.

9. Natal and Neonatal Teeth
Some infants erupt teeth before birth
(natal teeth) or shortly thereafter
(neonatal teeth).
Extraction of these incisors may be
considered if they are mobile,
interfere with breastfeeding, or lead
to Riga-Fede ulceration.
Glossary: Riga-Fede Disease: Ulceration of the lingual frenum or ventral surface of the tongue in infants caused by abrasion of the tissue against natal or neonatal teeth.

10. Delayed Eruption
Delayed eruption of more than 12 months can be caused by:
Endocrine disorders
Genetic disorders
Oral space issues
Dense gingival tissue
Dental infection
Radiation therapy
It is reasonable to refer a child who has not erupted a tooth by
18 months of age to a dentist if they are not seeing one already.
Notes:
Oral space issues such as another tooth blocking eruption or impacted teeth can delay eruption.
Endocrine disorders that can delay tooth eruption include hypothyroidism, disorders of calcium/phosphorus metabolism, and hypopituitarism (deficient production of growth hormones by the pituitary gland).
Genetic disorders that can delay eruption include ectodermal dysplasias, Down syndrome, and cleidocranial dysostosis (a rare condition inherited in an autosomal dominant fashion and characterized by partial or complete absence of the clavicles, defective ossification of the skull, and faulty occlusion due to missing, misplaced, or supernumerary teeth).

11. Early Exfoliation
Early exfoliation may be the result of the following causes:
Tooth destruction from dental caries
Trauma
Endocrine disorders, immune disorders, or other disorders
Notes:
Endocrine disorders such as diabetes and hypophosphatasia can cause early exfoliation.
Immune disorders such as neutropenia, neutophil defects, and HIV can cause early exfoliation.
Other disorders that cause early exfoliation include Ehlers Danlos syndrome type VIII, or eosinophilic granuloma/Langerhan’s Cell Histiocytosis.
Glossary: Hypophosphatasia: A congenital metabolic disorder characterized by a deficiency of alkaline phosphatase and usually resulting in demineralization of bone.
Neutropenia: Leukopenia in which the decrease in white blood cells is chiefly in neutrophils.

12. Delayed Exfoliation
Delayed tooth loss can be caused by a variety of disorders, including:
Endocrine disorders such as hypothyroidism or hypopituitarism
Ectodermal dysplasias
Genetic disorders
Notes: Genetic disorders that can caused delayed exfoliation include Down syndrome, Apert syndrome, Achondroplasia, and Osteogenesis imperfecta.
Glossary: Hypopituitarism: Deficient production of growth hormones by the pituitary gland.

13. Abnormal Teeth
A number of tooth abnormalities can occur in development.
These abnormalities can relate to the shape, color, physical structure, or
number of teeth.

14. Abnormal Teeth, continued
Hypodontia can be caused by the same problems that delay eruption.
Anodontia is extremely rare and most often associated with hypohydrotic ectodermal dysplasia. Hyperdontia can be associated with genetic disorders such as cleidocranial dysostosis and Gardner’s syndrome (Familial Adenomatous Polyposis).
Notes:
Problems that can cause hypodontia include Down syndrome, ectodermal dysplasias, chemotherapy, or radiation therapy.
The prevalence of hypodontia is approximately 3% in the United States, excluding the absence of the third molars (wisdom teeth), which occurs in approximately 20% of individuals.
Hyperdontia prevalence ranges from 0.1% to 3.8%.
Glossary: Hypodontia: A congenital condition marked by a less than normal number of teeth; partial anodontia
Anodontia: An especially congenital absence of teeth
Hyperdontia: A congenital condition marked by a greater than normal number of teeth
Cleidocranial dysostosis: A rare condition inherited in an autosomal dominant fashion and characterized especially by partial or complete absence of the clavicles, defective ossification of the skull, and faulty occlusion due to missing, misplaced, or supernumerary teeth
Familial Adenomatous Polyposis: A disease of the large intestine that is marked by the formation especially in the colon and rectum of numerous adenomatous polyps which typically become malignant if left untreated; inherited as an autosomal dominant trait

15. Tooth Shape
Abnormal tooth shape can result from a variety of medical conditions.
Hutchinson incisors and
Mulberry teeth are caused
by congenital syphilis.
Notes:
Conical teeth are caused by ectodermal dysplasias.
Hutchinson Teeth

16. Tooth Color
Abnormalities in tooth color can result from a number of causes.
Food pigments can stain the teeth, although these changes should be
temporary. Smoking can also discolor the teeth.
Excess fluoride intake can cause a range
of color changes, from a lacy, chalky
white discoloration to severe brown staining
of the teeth.
Notes:
High fevers during tooth formation can cause tooth discoloration or lines in the teeth.

17. Tooth Color, continued
Abnormalities in tooth color can also be caused by the following:
Nerve necrosis secondary to trauma
Severe caries
Tetracycline use by a pregnant mother
in the second half of pregnancy or by
a child early in life
Oral iron supplementation
Poor oral hygiene
Medical problems
Notes:
The dark discoloration often caused by oral iron supplementation may require a dentist’s assistance for removal.
Medical problems that can affect tooth color include porphyria, hyperbilirubinemia, and amelogenesis imperfecta.
Glossary: Porphyria: Abnormalities of porphyrin metabolism characterized by excretion of excess porphyrins in the urine and by extreme sensitivity to light
Hyperbilirubinemia: The presence of an excess of bilirubin in the blood
Amelogenesis Imperfecta: Faulty development of tooth enamel that is genetically determined
Iron Staining

18. Teething Care
Teething and symptoms attributed to teething are a common concern
of parents.
It is important to inform parents that none of these symptoms consistently
and accurately predict when teething is about to occur:
Congestion or cough
Sleep disturbance
Decreased appetite for liquids
Vomiting
Loose or increased stools
Notes:
A number of studies have looked at teething and associated symptoms, with the largest study observing that the symptoms of "increased biting, drooling, gum rubbing, sucking, irritability, wakefulness, ear rubbing, facial rash, decreased appetite for solid foods, and mild temperature elevation were all statistically associated with teething.” No single symptom occurred in more than 35% of infants.
Serious symptoms such as fever (>100.4º F) and diarrhea should not be attributed to teething and may require further evaluation to rule out a bacterial source of infection.

19. Teething Care, continued
The recommended intervention for teething is the use of cold items because
the cold acts as an anesthetic for the gums.
Suggested items include:
Pacifiers
Spoons
Clean wet washcloths
Frozen bagels or bananas
Refrigerated teething rings
Notes:
Teething rings should be placed in the refrigerator and not the freezer to prevent infants from developing fat necrosis.

20. Teething Care, continued
Topical teething gels sold over-the-counter (OTC) are often used for teething.
These gels can carry serious risks, such as local reactions, seizures with
overdose, and methemoglobinemia.
If necessary, parents should be instructed on proper dosing of OTC analgesic
medications, such as acetaminophen or ibuprofen.
Glossary: Methemoglobinemia: The presence of methemoglobin in the blood due to conversion of part of the hemoglobin to this inactive form

21. Malocclusion
Malocclusion can be a functional problem, an aesthetic issue, or a hindrance
to maintaining good oral hygiene.
Examples of malocclusion include anterior open bite, anterior crossbite, and
posterior crossbite.
Glossary:
Malocclusion: An abnormality in the coming together of teeth Anterior Open Bite: Vertical space between the upper and lower incisors resulting from opposing teeth failing to establish occlusal contact when the jaws are closed Anterior Cross Bite: Malocclusion in which the maxillary incisors are posterior to (behind) the mandibular incisors
Posterior Crossbite: Malocclusion in which the posterior maxillary molars or premolars are lingually displaced inside of the mandibular teeth
Anterior Open Bite
Anterior Crossbite
Posterior Crossbite

22. Malocclusion, continued
Signs and symptoms of malocclusion include:
Abnormal alignment of teeth
Abnormal appearance of the face
Difficulty or discomfort when biting or chewing
Bruxism
Glossary:
Bruxism: The habit of unconsciously gritting or grinding the teeth especially in situations of stress or during sleep

23. Malocclusion, continued
Malocclusion is usually genetic or congenital in origin.
Examples of genetic causes include congenital absence of teeth, cleft lip or
palate, skeletal disorders, and muscular problems.
Malocclusion can also result from environmental
factors, such as prolonged thumb sucking,
pacifier use, or tongue thrusting.
Patients with malocclusions should be referred to a dental professional.
Notes:
Helping families address pacifier and thumb sucking issues at an early age may prevent or minimize malocclusion.
Physicians can encourage patients treated by dental professionals to use prescribed appliances, such as retainers, consistently and as directed by the dental professional.

24. Question #1
A parent asks you how many "baby teeth" her child will eventually
have. What is the most appropriate response?
A. 18 teeth.
B. 20 teeth.
C. 28 teeth.
D. 32 teeth.
E. None of the above.

25. Answer
A parent asks you how many "baby teeth" her child will eventually
have. What is the most appropriate response?
A. 18 teeth.
B. 20 teeth.
C. 28 teeth.
D. 32 teeth.
E. None of the above.

26. Question #2 Which of the following is true of malocclusion?
A. It can be an aesthetic problem.
B. It can interfere with proper oral hygiene.
C. It can make eating difficult.
D. Examples include an anterior open bite and a posterior crossbite.
E. All of the above.

27. Answer Which of the following is true of malocclusion?
A. It can be an aesthetic problem.
B. It can interfere with proper oral hygiene.
C. It can make eating difficult.
D. Examples include an anterior open bite and a posterior crossbite.
E. All of the above.

28. Question #3 You are seeing a 15-month-old healthy boy for his 15-month
routine visit. He was not premature. The parents are concerned
because he has not yet erupted any teeth, a finding you confirm on
examination. Which is the most appropriate course of action?
A. Reassure the family. If the child appears normal, you are not concerned
unless no teeth have erupted by 2 years of age.
B. Refer to a dentist for evaluation.
C. Obtain a panoramic X-ray of the teeth to ensure that they have developed
normally.
D. Refer to an endocrinologist for evaluation, as delayed tooth eruption has a
known association with several endocrinopathies.
E. Wait 3 months and refer to a dentist if no teeth have erupted by the 18
month routine visit.

29. Answer You are seeing a 15-month-old healthy boy for his 15-month
routine visit. He was not premature. The parents are concerned
because he has not yet erupted any teeth, a finding you confirm on
examination. Which is the most appropriate course of action?
A. Reassure the family. If the child appears normal, you are not concerned
unless no teeth have erupted by 2 years of age.
B. Refer to a dentist for evaluation.
C. Obtain a panoramic X-ray of the teeth to ensure that they have developed
normally.
D. Refer to an endocrinologist for evaluation, as delayed tooth eruption has a
known association with several endocrinopathies.
E. Wait 3 months and refer to a dentist if no teeth have erupted by the 18
month routine visit.

30. Question #4
True or False? Excess fluoride intake can cause irreversible tooth
discoloration.
A. True.
B. False.

31. Answer
True or False? Excess fluoride intake can cause irreversible tooth
discoloration.
A. True.
B. False.

32. Question #5 When do the primary (baby) teeth begin to erupt?
A. It varies from child to child.
B. Around 6 months of age.
C. Around 9 months of age.
D. Around 12 months of age.
E. Around 18 months of age.

33. Answer When do the primary (baby) teeth begin to erupt?
A. It varies from child to child.
B. Around 6 months of age.
C. Around 9 months of age.
D. Around 12 months of age.
E. Around 18 months of age.

34. References
1. Cunha RF, Boer FA et al. Natal and neonatal teeth: review of the literature.
Pediatr Dent, 2001; 23(2): Anderson JE. "Nothing but the tooth”: Dispelling myths about teething. Contemp Pediatr. 2004; 21:75.