1 The median is the middle value of the data set. 2  The lower quartile (Q 1) is the median of the lower half of the data set. 3  The upper quartile (Q 3) is the median of the upper half of the data set. 4  The interquartile range (IQR) is the spread of the middle 50% of the data values.
Removable Essix retainers typically cost between $100-$250 for one or $200-$500 for two. They are made from a vacuum sealed clear plastic that is less noticeable but more likely to break or warp, meaning that you could be paying the price more than once for this style of retainer.
1 Note that baking soda is abrasive and regular use can damage your retainer. 2  Retainers usually cost 100 to 300 dollars. 3  You may use a soft toothbrush and a small amount of non-abrasive toothpaste to clean most retainers. ( 4 Note that a toothbrush could put scratches on a clear Invisalign or clear Essix retainer). Clean your retainer thoroughly at least once a day to keep it fresh and free from bacteria and tartar buildup. 2  Always rinse your retainer after you remove it. 3  Dry saliva will cause a buildup of tartar on your retainer. 4  Remove your retainer and rinse it in warm water before you sit down to eat.