What is Space Analysis in Primary dentition?
- The purpose of mixed dentition analysis (MDA) 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.
Lee-way Space
- The space occupied by the primary canines and molars is greater than that required for the corresponding permanent teeth, the canine and the
two premolars. - This size difference of the primary and
permanent teeth is known as the “Leeway Space”
Why Space Analysis in Primary dentition is important?
* The available space in the arch can be:
* This becomes fundamental in determining the treatment plan that
might involve:
- The available space in the arch can be: equal, greater or smaller than the unerupted teeth.
- This becomes fundamental in determining the treatment plan that might involve:
- Extractions- primary and perm teeth extracted
- Eruption guidance-extract only primary
- Space maintenance.
- Space gain.
- Simple monitoring.
The methods employed for MDA can be grouped into three categories:
- Use regression equations
- Use radiographs
- combination of both.
Among the different MDA methods reported in the literature, those
based on ? are the most widely used, types?
Among the different MDA methods reported in the literature, those based on the regression equations are the most widely used.
* Moyers’ probability tables
* Tanaka and Johnston (T/J) equations
drawback of regression analysis
The major drawback of these analyses is applicability only after the eruption of mandibular permanent incisors.
Tanaka and Johnston Analysis
- Tanaka and Johnston analysis is a mixed dentition analysis which allows one to estimate the space available in an arch for the permanent teeth to erupt.
- All you need to do is to measuring the MD width of all lower incisors.
Tanaka - Johnston Analysis
flow chart
Max: predicted mm for MD width of canine and PM’s
Man: predicted mm for MD width of C and both PM’s
Boston University Approach
3+4+5 = 2D + C
(lower)
Space analysis in permanent dentition
* It determines?
- It determines the difference between space available and space required for alignment of permanent teeth
How to perform this permanent dentition analysis?
- Measure the mesio-distal width of each tooth mesial to the first permanent molar.
- The total sum of the width corresponds to the necessary space required to be compared to width available.
- Compare these two numbers together. (+ enough space, = just enought space, - crowding present)
Space analysis in permanent dentition components
- Visualization
- Localized
- Arch perimeter
- Segmental arch analysis
- Digital 3D scanning
Visualization of perm dentition:
* Nothing is more important than?
* Assessing both arches for?
- Nothing is more important than clinical examination.
- Assessing both arches for overall evaluation of the teeth and their alignments.
Localized approach to perm dentition
- Try to figure out where the problem is:
- Anterior.
- Posterior.
Arch perimeter analysis:
* Always compare each arch with?
- Always compare each arch with the ideal arch in your mind.
Arch Circumference analysis
- When you are dealing with crowded arch, accurate assessment of the arch circumference is crucial.
Arch perimeter measurement tools?
- One on the most accurate devices to messure tooth mass (M-D size) is a digital caliper.
- Manual caliper can be used too, with less accuracy and more human error
what is this
space maintenance with rigid fixed appliance for non-erupted teeth (prevent M drift of molars and loss of space)
Segmental arch analysis
- For each side:
1. Measure M-D width of every single tooth.
2. Measure mesial of 1st molar to distal of lateral incisor.
3. Measure distal of lateral incisor to mid- line.
Digital 3D scanner use for space analysis
- Using digital devices to measure the width of each tooth by plotting mesial and distal contact points of each tooth.
- M-D contact points of each tooth can be plotted and measured on a digital cast.
- M-D contact points of each tooth can be plotted and measured on a digital scanned of the arch too.
cast manipulation in 3d analysis
must get full occlusal view of tooth for accurate measurement, can be difficult
