Lecture 3: Development of Dentition

Study Notes

Divided into four categories: Neonatal Period, Primary Dentition, Mixed Dentition, and Permanent Dentition.

Neonatal Period: Ranges from birth to 6 months, characterized by only posterior gum pads making contact when biting, while anterior space remains open.
During this period, mandibular teeth develop more rapidly than maxillary teeth (90% of cases).
Unique to this stage, a "nasal tooth" may occasionally appear.
Maxillary gum pads extend beyond the mandible, resulting in a convex facial profile.

Also known as visceral swallow; involves the tongue resting between the gum pads with jaws apart.
Triggered by sensory interactions between lips and tongue, associated with tongue and mandibular thrust.

Identified between maxillary lateral incisor and canine, as well as between the mandibular canine and first molar, facilitating future tooth alignment.

This space is important for the normal development of permanent dentition, addressing size discrepancies between teeth and jaw.

Occurs due to either small jaw size or larger teeth, indicative of potential crowding in the developing permanent dentition.

Refers to the mesio-distal relationship of the distal surface of the maxillary and mandibular deciduous second molars.
Types of Terminal Planes:
- Flush Terminal Plane: Occurs in 74% of cases; the distal surfaces of the upper and lower molars are in alignment, representing a normal primary dentition relationship.
- Mesial Step: Seen in 14% of cases where the distal surface of the lower molar is more mesial compared to the upper molar.
- Distal Step: Present in 10% of cases, characterized by the distal surface of the lower molar being positioned more distally than the upper molar.

Also referred to as somatic swallow; involves the relaxation of the lips and placement of the tongue behind the maxillary incisors.
The mandible elevates until the posterior teeth come in contact, indicating a mature swallowing pattern.