Lecture 2 Flashcards
What is the purpose of mixed dentition (MDA) analysis?
The purpose is to calculate the differences between the amount of the dental arch space available and that required for accommodating the permanent teeth for planning either preventive or interceptive approach
What is Lee-Way Space?
The size difference between the primary and permanent teeth
The space occupied by the primary canines and molars is ____ compared to the space required for the corresponding permanent teeth (canine + 2 premolars)
GREATER THAN
Why is determining the space analysis in primary dentition important?
It becomes fundamental in determining the treatment plan that might involve:
- extractions
- eruption guidance
- space maintenance
- space gain
- simple monitoring
The available space in the arch can be ___, ___, or ____ than the unerupted teeth
equal; greater; smaller
What are the 3 categories of methods for mixed dentition analysis (MDA)?
- Use regression equations
- Use radiographs
- Combination of BOTH
Of the 3 MDA categories, which method is most widely use?
Regression equations
- movers probability tables
- Tanaka and Johnston equations
What are the two regression equations used in MDA?
- Moyer’s probable;oty tables
- Tankaka and Johnston equations
What is the major draw back with MDA methods and space analysis?
Only applicable AFTER the eruption of the mandibular permanent incisors
A mixed dentition analysis that allows one to estimate the space available in the arch for the permanent teeth to erupt:
Tanaka and Johnston Analysis
In Tanaka and Johnston Analysis, what is measured?
MD width of all lower incisors
For TJ analysis you take the MD width of all lower incisors and add ___ for maxillary and add ___ for mandibular
11 maxillary; 10.5 mandibular
For TJ analysis you take the MD width of all lower incisors and add 11. You are predicting:
maxillary arch canine and 2 premolars
For TJ analysis you take theMD width of all lower incisors and add 10.5. You are predicting:
mandibular arch canines and 2 PM
“two times the width of the primary first molar + the MD width of the primary canine”
Boston University approach
In the Boston university approach what is measured? Be specific
2x Width of primary first molar (D) + with of primary canine (C)
2D + C
The Boston university approach measurements are taken on the:
lower arch
List the equation for the Boston university approach:
3+4+5 = 2D + C
Image with space maintainer
(all permanent central incisors and permanent 1st molar, missing premolars, also some primary teeth remaining)
What is the function of the space maintainer?
Preventing the MD drift of the molars and shifting of the lower incisors
What does the space analysis in the permanent dentition help to determine?
Helps determine the difference between the space available and the space required for the alignment of the permanent teeth
IN permanent dentition space analysis, what does a POSITIVE number mean?
more space available than needed
IN permanent dentition space analysis, what does a NEGATIVE number mean?
crowding (less space available than needed)
IN permanent dentition space analysis, what does the SAME number mean?
Exact space present required for teeth
How can you perform the permanent dentition analysis?
- Measure the MD width of each tooth mesial to the first permanent molar
- The total sum of the width should correspond to the necessary space required
- Compare the numbers together
