DEVELOPMENT AND ERUPTION OF THE TEETH

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DEVELOPMENT AND ERUPTIONOF THE TEETH

• Dr. Samir M. Ziara
• B.D.S. (Alexandria Univ.)
• D. D. P. H. Royal Collage of Surgeon (London)
• M. Sc. P. H. Al-Quds Univ.
• Diploma of H. Administration

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Two years old
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Five years
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8 years
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8 YEARS
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DEVELOPMENT AND ERUPTION OF THE TEETH

• Historically the term eruption has been used to
  denote emergence of the tooth through the gingiva
  although it denotes more completely continuous
  tooth movement from the dental bud to occlusal
  contact .
• However, the terms eruption and emergence will
  be used here at this time in such a way as to
  avoid any confusion between historical use of
  emption and its more recent expanded meaning.

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• Dental age has been assessed on the basis of the
  number of teeth at each chronological age or on
  stages of the formation of crowns and roots of
  the teeth.
• Dental age during the mixed dentition period may
  be assessed on the basis of which teeth have
  erupted, the amount of resorption of the roots of
  primary teeth, and the amount of development of
  the permanent teeth.

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• Calcification or mineralization (most often
  visualized radiographically) of the organic
  matrix of a tooth, root formation, and tooth
  eruption are important indicators of dental age.
• Dental age can reflect an assessment of
  physiologic age comparable to age based on
  skeletal development, weight. or height.

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• However, when forming, the crowns and roots of
  the teeth appear to be the tissues least affected
  by environmental influences (nutrition,
  endocrinopathies. etc.), and dentition may be
  considered to be the single best physiological
  indicator of chronological age in juveniles

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Dental development may be based also on the
emergence (eruption) of the teeth however,
because caries, tooth loss. and severe
malnutrition may influence the emergence of teeth
through the gingiva, chronologies of the eruption
of teeth are less satisfactory for dental age
assessment than those based on tooth formation.
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In addition, tooth formation may be divided
appropriately into a number of stages that cover
continuously the development of teeth, in
contrast to the single episode of tooth eruption.
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The importance of the emergence of the teeth to
the development of oral motor behavior is
frequently overlooked, no doubt partly as a
result of the paucity of information available.
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However, the appearance of the teeth in the mouth
at a strategic time in the maturation of the
infant's nervous system and its interface with
the external environment must have a profound
effect on the neurobehavioral mechanisms
underlying the infants development and learning
of feeding behavior, particularly the acquisition
of masticatory skills.
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TOOTH FORMATION STANDARDS

• Events in the formation of human dentition are
  based primarily on data from studies of dissected
  prenatal anatomic material and from radiographic
  imaging of the teeth of the same subjects over
  time (longitudinal data) or of different subjects
  of different ages seen once (cross-sectional
  data).

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• From these kinds of studies both descriptive
  information and chronological data may be
  obtained.
• To assemble a complete description or chronology
  of human tooth formation it would seem necessary
  to use data based on more than one source and
  methodology.
• However, it is not easy to define ideal tooth
  formation standards from studies based on
  different variables and many different
  statistical methods.

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• Subjects surveyed in most studies of dental
  development are essentially of European
  derivation, and population differences can only
  be established by studies that share methodology
  and information on tooth formation in
  nonwhite/non-European-derived populations

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SCHOUR AND MASSIER (1940)