enamel hypoplasia as a

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Enamel Hypoplasia as a Prerequisite to Rampant Caries Yihong Li, DDS, MPH, DrPH Timothy Bromage, PhD Page W. Caufield, DDS, PhD

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Enamel Hypoplasia as aPrerequisite to Rampant Caries

Yihong Li, DDS, MPH, DrPH

Timothy Bromage, PhD

Page W. Caufield, DDS, PhD

Yihong Li in the field

EHP_Beijing, 1996

Enamel hypoplasia (EHP)• Developmental Enamel Defects (DED)

– Various forms of enamel defects seen• Linear

• Pitted

• Opaque (most commonly called hypoplasia)

• Decreased and flawed mineralization, surfaceirregularities

– Colonization/retentive sites for cariogenic bacteria

– Less resistant to acid attack

• Position and extent of defect corresponds timeof insult

Hypoplasia vs White Spot Lesion?

Early – Moderate – Advanced - New definitions?

Conditions preceding EHP

• Malnutrition

• Low birthweight

• Prematurity

• Maternal illness

• Smoking

• Drug abuse

• Liver disease

• Other systemic diseases

Contributing factors tosubsequent caries

• High sugar intake

• Mutans streptococci

– Early colonization of EHP

– MS dominate biota

– Source?

• Poor oral hygiene

• Incisor crowding

• Difficulty with early detection by HCW

SEM scan S-ECC incisor

Prevention of ECC begins with intervention in the pre-natal and perinatal

periods.11 Women should be advised to optimize nutrition during the thirdtrimester and the infant’s first year, when enamel is undergoing maturation.Enamel hypoplasia is common in children with low birthweight or systemicillness in the neonatal period.12,13 There is considerable presumptiveevidence that malnutrition/undernutrition during the perinatal period causeshypoplasia.14 A consistent association exists between clinical hypoplasia andECC.12,15 Cariogenic bacteria (specifically mutans streptococci) may betransmitted to the child; decreasing the mother’s/primarycaregiver’s/sibling(s)’ mutans streptococci …………….

ECC = S-ECC?

Evidence supporting perinatalevents predate EHP

• 37 published studies in literature

• 3 studies

– Li et al., 1994

– Needleman et al., 1994

– Seow, et al.,

EHP_Beijing, 1996

•Macroscopic examination of 455 primary incisors from childrenhaving perinatal histories

•Enamel defects reported in 77% of children from"underdeveloped" countries. This study – 18.5% prevalence

•Antecedents to hypoplasia:

•Delayed pre-natal care past first trimester (p <0.007)

•Premature labor (p<0.004)

•Prematurity (p<0.001)

•Special care nursery (p<0.005)

•Greater prepregnancy weight of mothers (p<0.001)

•Measles infection (p<0.0008)

•Smoking (p<0.008)

1994

•Case-control study of 617 Australian children age <4 yo

•S-ECC group receiving restorative treatment under generalanesthesia

•EHP significantly higher among Aboriginal population

•Correlation to low household income, mother education,employment status (p<0.001)

•Significant risk indicators:

•Enamel hypoplasia (OR 4.2)

•Presence of S. mutans (OR 4.8)

•Sweeten drinks/diet (OR 4.0)

•Mother's anxiety (OR 5.1)

Caries Research 2009

• 25 percent of this racial group lives at the poverty level.

• American Indian/Alaska Native infants are 3.7 times aslikely as non-Hispanic white infants to have mothers whobegan prenatal care in the 3rd trimester or did notreceive prenatal care at all.

• American Indian/Alaska Native adults were 2.3 times aslikely as white adults to be diagnosed with diabetes.

• American Indian/Alaska Native adults were 1.6 times aslikely as White adults to be obese.

S-ECC?

Enamel Hypoplasia (EHP)

- pits -

EHP_Beijing, 1996

Linear enamel hypoplasia onprimary incisors

EHP + Caries

EHP_Beijing, 1996

Caries over EHP lesionspattern!

EHP_Beijing, 1996

Rapp R. & Winter GB, 1979

Prenatal EHPThe marked EHP affecting the 2/3 ofthe enamel on these maxillary primaryincisors is evidence of a severemetabolic disturbance occurredprobably during the 2nd and 3rd

trimesters of pregnancy.

Neonatal EHPThe wide band of EHP affecting theprimary teeth in this case wasassociated with preterm birth and awith weight of approximately 1.3 kg.LBW immature babies sufferconsiderable metabolic disturbanceduring the neonatal period and this isoften reflected in defectiveamelogenesis.

EHP first, then caries

Brazil_ 1999

Primary central incisor crown

Neonatal lines in enamel and dentine

EDJ

Primary centralincisor crown fromchild with S- ECC

Carious enamel

Neonatal line in dentine only

Primary centralincisor crown fromnormal child

CROWN FORMATION

Appositional stage

Striae ofRetzius

Perikymata

Cross-striations

Imb

rica

tion

al

sta

ge

Enamel

Hunter-Schregerbands

Prisms

Dentine

EDJ

ENAMEL CROWN STRUCTURE

Rozzi, F.R., Walker, C., Bromage, T.G. 1999 Early hominid dental development and climate change. In (Bromage, T.G., Schrenk, F., Eds) African Biogeography, ClimateChange, and Early Hominid Evolution. Oxford University Press: New York. pp. 349-363.

Dentinehorns

Pulp

Dentine

Enamel

EDJ

*2

*1

*1

*2

Bromage, T.G. 1991 Enamel incremental periodicity in the Pigtailed Macaque: A polychrome fluorescent labeling study of dental hard tissues. American Journal of PhysicalAnthropology,86:205-214.

ENAMEL INCREMENTAL DEVELOPMENT

ENAMEL CELLS SHOW CIRCADIAN OSCILLATION

Enamelprismorientationand directionof growth

Striae ofRetzius andtheinstantaneousforming front

Daily cross striations

ENAMEL CROSS STRIATIONS

Striae of Retzius

ENAMEL STRIAE OF RETZIUS

ENAMEL STRIAE OF RETZIUS AND HOMININ BODYSIZE

Bromage, T.G., Lacruz, R.S., Hogg, R., Goldman, H.M., McFarlin, S.C., Warshaw, J., Dirks, W., Perez-Ochoa, A., Smolyar, I., Enlow, D.H., Boyde, A. 2009Lamellar bone is an incremental tissue reconciling enamel rhythms, body size, and organismal life history. Calcified Tissue International 84: 388-404.

Modern Human:

Range: 6-12 days♀ avg: 9 days♂ avg: 8 days

Basal Metabolic Rate (log)

Stri

aeo

fR

etz

ius

Re

pe

atIn

terv

al

r = 0.90, p < 0.001Callithrix pygmaea,Callithrix jacchus , Sagunius oedipus

Callimico goeldii, Leontopithecus rosalia,Aotus sp., Saimiri sciureus

Erythrocebus patas,Hylobates lar

Alouatta palliata Pan troglodytes

Papio anubis

Homo sapiens sapeins

Pongo pygmaeus

Relationship Between Striae of Retzius Repeat Interval and BMR(ml O2/h) Among Primates

ENAMEL INCREMENTAL GROWTH RATE VARIABILITY

Striae of Retzius Perikymata

RELATIONSHIP BETWEEN STRIAE OF RETZIUSAND PERIKYMATA

Dean, M.C., Wood, B.A. 1981 Developing pongid dentition and its use for ageing individual crania in comparative cross-sectional growth studies. Folia Primatologia 36:111-127.

HUMAN DENTALDEVELOPMENT ANDCALIBRATED ENAMELINCREMENTS

Bromage, T.G. & Dean, M.C. 1985 Re-evaluation of the age at death of immature fossil hominids. Nature, 317:525-527.

PERIKYMATA (SEM)

PERIKYMATA(CSOM)

ENAMEL SURFACE TOPOGRAPHIESARE HAVENS FOR MICROBES