MDS PREP
Primary teeth begin to calcify between the ________ and ________months in
utero.
1) first; second
2) second; fourth
3) fourth; sixth
4) sixth; eighth
The primary teeth begin to form in utero at about six weeks. Hard tissue
formation occurs in all primary teeth by the 18th week in utero. 3. The
permanent teeth begin to develop at approximately four months of age in utero.
Maxillary and mandibular first molars begin to calcify at birth.
The permanent anterior tooth most often missing congenitally is the
1. maxillary central incisor
2. mandibular central incisors
3. mandibular lateral incisors
4. maxillary lateral incisors
Dental Anatomy
Answer: 4
lateral incisor is most often missing congenitally
If a 4th root canal is present in a maxillary 1st molar, it will likely be located in which of the following roots?
1) Mesiolingual
2) Mesiobuccal
3) Distolingual
4) Distofacial
Dental Anatomy Answer: 2
Well over 50% of maxillary 1st molars have two canals in the mesiobuccal root. Some authors cite the number as high as 90%.
There are usually 3 roots and 4 canals in a maxillary 1st molar.
The fourth canal, the mesiolingual canal, is also referred to as: the accessory mesiobuccal canal, mesiocentric, mesiopalatal canal or MB2.
It is usually tough to find MB2 through clinical inspection and it is not obvious on a radiograph. A dentist should expect it is present before beginning a root canal on the first maxillary molar.
How soon after the eruption of permanent tooth is the apex usually fully developed?
1. Immediately
2. 3-6 months
3. 2-3 years
4. 6-9 years
Dental Anatomy
Answer: 3
Afet tooth eruption in permanent teeth the apex is fully developed after 2-3 years
Which of the following muscles has two separate functions in mandibular
movement
1) Masseter
2) Geniohyoid
3) External(lateral)pterygoid
4) Buccinator
Anatomy Answer: 3
The external (lateral) pterygoid muscle has two primary functions: it assists in depressing the mandible (opening the mouth) and in moving the mandible forward (protrusion). This dual function distinguishes it from other muscles of mastication, which primarily elevate the mandible.
The tendon of anterior belly digastric passes between the tendon ends of:
1. Styloglossus muscle
2. Stylohyoid muscle
3. Hyoglossus muscle
4. Posterior belly of digastric
Anatomy
Answer: 2
The tendon of anterior belly digastric passes between the tendon ends of Stylohyoid muscle
During eruption of permanent teeth, alveolar bone is
1. deposited only
2. resorbed only
3. resorbed and deposited intermittently
4. neither resorbed nor deposited
Dental Anatomy Answer: 3
During eruption of permanent teeth, alveolar bone is resorbed and deposited intermittently
Immediately following the closure of the A-V valves is the period of
1. Isotonic contraction
2. Isometric contraction
3. Isometric relaxation
4. Isotonic relaxation
Anatomy
Answer: 3
Immediately following the closure of the A-V valves is the period of
Isometric relaxation