Flashcards in Test 1 Deck (131)
The combined MD widths of 1st, 2nd primary molars and primary canine compared to the corresponding combined MD widths of successor 1st, 2nd premolars and canine. MN is +1.7 mm per side. MX is +.9 mm per side. You can control the leeway space using space supervision to accomodate minor crowding.
Genetic factors in permanent tooth eruption?
Familial, gender, race.
Environmental factors in permanent tooth eruption?
Local interference (supernumerary tooth), low birth weight, premature birth, trauma.
Systemic factors in permanent tooth eruption?
What are the eruptive phases?
Pre-eruptive: Root formation begins, tooth moves from bony vault to oral cavity surface. Eruptive: prefunctional. Tooth in oral cavity without occlusal contact. Root length is 1/2-2/3. Eruptive functional: Occlusal contact. Dentition continually has movement.
What is the variation in timing that is within normal limits?
+/- 6 months. Mean age of eruption of permanent teeth does not correlate with physical development.
How long does it take for root completion for primary and permanent teeth?
Primary: 18 months post eruption. Permanent: 3 years post eruption.
How long is the duration of full eruption for a permanent tooth?
About 5 years.
At the time of clinical emergence about how much of the root is formed for a permanent tooth?
How do you predict premolar tooth emergence?
Erupting premolars generally require 6 months to move through 1 mm of bone as measured on a bite wing.
How does bone loss from infection affect eruption?
What is dental age determined by?
Teeth erupted, resorption of primary roots, degree of successor root development.
In anterior dentition, how does premature tooth loss affect successor eruption?
Less than 3 years, delayed. More than 5 years, accelerated.
In posterior dentition, how does premature tooth loss affect successor eruption?
Less than 7 years, delayed. More than 5 years, accelerated.
Where do the resorption patterns occur?
MX incisors: Diagonal. MN incisors: horizontal. Molars: furcation
What is the most favorable eruption sequence of permanent teeth?
1. First molars
4. MN canine and MX 1st premolar.
5. MX 2nd premolar and MN 1st premolar.
6. MN 2nd premolar and MX canine.
7. 2nd molars.
MN vs. MX canine eruption?
MN erupts before the premolars. MX erupts after the premolars.
Delayed Tooth Eruption DTE
Most common deviation in eruption. Biologic: eruption has not occurred even though there has been formation of 2/3 or more of the root. Chronologic: Characterized by the relationship to expected tooth eruption time. 2 standard deviations from the average. Scar tissue, supernumerary teeth, oral cleft, tumors, enamel pearls, ectopic eruption, eruption hematoma, etc.
Permanent canine erupted in place of the lateral incisor.
Interrupted eruption, possible space loss from tipped adjacent teeth. Etiology unknown. Possibly familial, common for more than 1 tooth. MN primary molars are the most common. Should exfoliate normally. Want to monitor and not extract as to not damage the successors.
Minor eruption variation is normal. Variation less than 6 months between contralateral teeth is normal. Normal variation +/- 18 months.
Which tooth is most likely to become impacted?
Last tooth due to lack of remaining space. 3rd molars, then MX canine.
Which teeth most commonly erupt ectopically?
MX 1st permanent molars and MN lateral incisors.
What causes eruption with malposition?
Chronic extensive bone loss. Crowding and interference.
No therapy required unless symptomatic.
Neonatal inclusion cysts
Developmental white soft tissue lesions. Asymptomatic and no treatment indicated. Will resolve in 3 mo. No gender predilection. Gingival/dental lamina, palatal
Occur in up to 50% of neonates. Solitary or multiple discrete or clustered papules on alveoplar mucosa. Mostly on MX. Smooth, translucent to pearly white. 1-3 mm. Keratin filled remnants of dental lamina.
85% of neonates. Asymptomatic and resolve in first month. Keratin filled cysts that are possible remnants of epithelial tissue trapped in raphe during fetal development. Smooth pearly white pearl like lesion on median palatal raphe. Solitary or multiple discrete.
Same clinical findings as epstein pearls. Remnants of minor salivary gland tissue. Histologically different. Located away from palatal raphe and on the junction of hard and soft palate.