24 Questions
What is the primary reason why maxillary and mandibular first permanent molars serve as the 'Key of Occlusion'?
They are the first teeth to erupt in the oral cavity.
In Angle's Classification, which class of malocclusion is characterized by a retrognathic profile?
Class II
What is the term for the maximum intercuspation of the teeth when the condyles are in the most retrusive, unstrained position in the glenoid fossa?
Centric occlusion
Which of the following statements is TRUE regarding the loss of a tooth?
The opposing tooth may elongate.
What is the term for the relationship between the maxillary and mandibular teeth when the condyles are in the most retrusive, unstrained position in the glenoid fossa?
Centric occlusion
Which class of malocclusion is characterized by an anterior crossbite?
Class III
What is the primary function of the maxillary and mandibular first permanent molars in the oral cavity?
To serve as a guide for the eruption of other teeth
In Angle's Classification, which class of occlusion is characterized by a normal tooth-to-tooth relationship?
Class I
What is the average amount of crowding of the incisors as they erupt?
1.6 mm
What is the term for the difference in size between primary molars and premolars?
Leeway space
In which phase do the canines erupt and force themselves between the lateral incisors and first premolars?
Fourth phase
What is the term for the relation of the upper and lower teeth during various jaw movements?
Dynamic occlusion
What is the position of the condyles in centric occlusion?
Most retrusive-unstrained position
When do the second molars emerge in the eruption sequence of permanent teeth?
Fourth phase
What is the term for the contact of teeth in opposing dental arches when the jaws are closed?
Static occlusal relationships
What is the term for the relation of upper and lower teeth when the upper and lower teeth are in maximum intercuspation?
Centric occlusion
What is the relationship between the buccal cusps of upper 6 and the lower 6?
Free, in the opposing MB groove of lower 6
What is the primary cause of an anterior open bite?
Thumb sucking
What is the significance of the curvature of the cervical line in tooth crowns?
It is a direct factor in the protective functional forms of the tooth crowns
What is the relationship between the lingual cusps of upper 6 and the lower 7?
In contact with the MMR of lower 7
What is the purpose of the labial, buccal, and lingual contours of the tooth crowns?
To hold the gingiva under definite tension
What is the consequence of underdeveloped facial and lingual contours of the crowns?
The gingival margin will be forced apically
What is the characteristic of an anterior cross bite?
The upper anterior teeth are behind the lower anterior teeth
What is the primary function of the interproximal spaces?
To provide a pathway for food particles to escape
Study Notes
Buccal Relations of Maxillary First Molars
- The buccal cusps of upper 6 are free of contact, with the MesioBuccal Cusp (MBC) being in the opposing MB groove of lower 6, and the Distobuccal Cusp (DBC) being in the opposing embrasure between lower 6 & 7.
Lingual Relations of Maxillary First Molars
- The MesioLingual Cusp (MLC) makes contact in the central fossa of lower 6.
- The Distolingual Cusp (DLC) makes contact to the MesioMesial Ridge (MMR) of lower 7.
Forms of Malocclusion
- Anterior open bite is caused by thumb sucking.
- Anterior cross bite is a type of malocclusion, also known as Angle's class III.
The Physiologic Tooth Form and The Periodontium
- The protective functional forms of the tooth crowns include direct factors (proximal contact areas, interproximal spaces, embrasures, facial and lingual contours, and curvature of the cervical line) and indirect factors.
- The direct factors are essential for maintaining proper oral function and preventing malocclusion.
Labial, Buccal, and Lingual Contours of the Crowns
- The contours of the crowns hold the gingiva under definite tension, protect the gingival margin, and provide a proper degree of massage.
- Overdeveloped contours can deprive the gingiva of proper massage, while underdeveloped contours can force the gingival margin apically.
Centric Occlusion
- Centric occlusion is the most retrusive unstrained position of the condyles in the glenoid fossa.
- It is the key to proper occlusion, and the maxillary and mandibular 1st permanent molars serve as the "Key of Occlusion".
Classification of Occlusion
- Angle's Classification includes:
- Class I: Centric occlusion, with the MB cusp of 6 contacting the MB groove of 6.
- Class II: Malocclusion with a retrognathic profile.
- Class III: Malocclusion with an anterior cross bite.
Centric Occlusion of Permanent Teeth
- Each tooth in a dental arch occludes with two teeth in the opposing arch, except for the mandibular central incisor and the maxillary third molar.
- Loss of a tooth can lead to elongation of the opposing tooth, and proper alignment of the incisors requires completion of the dental arch form.
- Leeway space (4mm) is utilized for alignment of the incisors and adjustment of the proper occlusal relation of the maxillary and mandibular permanent 1st molar.
Eruption Sequence of Permanent Teeth
- The favorable eruption sequence of permanent teeth is:
- 1st molars
- 1st premolars
- 2nd premolars
- Canines
- 2nd molars
- Wisdom teeth
Occlusion
- Occlusion is the relation of the upper and lower teeth during various activities of the mandible.
- It includes both static occlusal relationships (when the jaws are closed) and dynamic occlusal relationships (during jaw movements).
This quiz covers the concepts of buccal and lingual relations of maxillary first molars, including their cusp contacts and forms of malocclusion. It's essential for dental students to understand these principles to diagnose and treat oral health issues.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
