10 Questions
What is the name of the continuous horizontal groove that separates the alveolar part from the hard palate?
Gingival groove
How many segments are the alveolar parts of the maxillary and mandibular gum pads divided into?
Ten
What is the relationship between the lateral sulcus of the maxillary and mandibular gum pads when they are approximated?
The maxillary sulcus is mesial to the mandibular sulcus
What is the relationship between the upper and lower gum pads in the anterior region when they are approximated?
They are apart
What is the characteristic feature of the maxillary gum pad in relation to the mandibular gum pad?
It is wider
What is the position of the tongue in the rest position?
It lies between the upper and lower gum pads
What is the characteristic feature of the upper lip at the age of deciduous dentition?
It is short and flaccid
What is the purpose of the transverse grooves on the alveolar part of the gum pads?
To denote the developing deciduous teeth
What is the relationship between the upper and lower gum pads at the first deciduous molar segment?
They are in contact
What is the purpose of the dental or gingival groove on the alveolar part of the gum pads?
To separate the hard palate from the alveolar part
Study Notes
Deciduous Dentition
- Flush terminal plane: The distal surfaces of upper and lower second deciduous molars are on the same plane, leading to an end-to-end relationship of the first permanent molars when they erupt distal to the second deciduous molars.
Mesial and Distal Steps
- Mesial step: The distal surface of the lower deciduous second molar is more mesial to the upper deciduous second molar, allowing the first permanent molars to erupt in a normal molar relationship.
- Distal step: The distal surface of the lower deciduous second molar is more distal to the upper deciduous second molar, possibly due to habits like thumbsucking or excessive growth of the maxilla.
Primate Space
- Primate space: A space between the deciduous incisors and canines, allowing for the difference in size between deciduous incisors and their permanent successors.
- Closure of primate space: The mandibular primate space is partially closed by the eruption of the permanent mandibular first molar, while the maxillary primate space is usually closed by the eruption of the permanent maxillary incisor.
Changing Occlusion of Deciduous Teeth
- Anterior teeth: Deciduous incisors are vertical with minimal overbite and overjet, but by 3 years of age, an excessive overbite develops, which is gradually reduced by rapid attrition of the incisors.
- Edge-to-edge incisor relationship: By 6 years of age, the overbite is reduced, and an edge-to-edge incisor relationship develops, facilitating the early forward growth of the mandible.
Relation Between Maxillary and Mandibular Posterior Teeth
- Class I molar relationship: The mandibular second primary molar is usually wider mesiodistally than the maxillary, giving rise to a flush terminal plane.
- Alveolar part: Separated from the hard palate by a continuous horizontal groove known as the dental or gingival groove.
Relationship between Upper and Lower Gum Pads
- Lateral sulcus: The maxillary gum pad has a more mesial lateral sulcus than the mandibular gum pad when approximated.
- Gum pad relationship: The upper gum pad is wider, leading to an overjet of the maxillary pad over the mandibular anteriorly.
- Rest position: The gum pads are apart, with the tongue projecting between them, forming the principal boundary to the front of the oral cavity.
Test your understanding of the relationship between deciduous upper and lower second molars, including the flush terminal plane and its implications for permanent molar eruption. Learn how spacing in deciduous dentition affects the development of permanent teeth.
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