Is replacing bonded tooth with a crown necessary to prevent root canal?
yes
Otoslerosis should not hinder scuba diving however it is necessary to clean the ear canal with ear buds to remove whatever moisure that's still there. This will prevent infection.
prevent disease caused by mosquitoes
Both use a levee system requiring water to fill to raise the boat to the height necessary for the next canal or in Panama to the level of sea water.
Episiotomy
William Gorgas helped prevent mosquitos during the proses of making the panama canal
Masonry is used to line water courses to prevent erosion of the banks.
The fine hairs in the external auditory canal help to trap and prevent debris, such as dust and particles, from entering the ear. This helps to keep the ear clean and prevent blockages. The tiny wax-producing glands in the external auditory canal secrete earwax (cerumen) which helps to lubricate and protect the ear canal from infection and irritation.
To prevent any infection that may occur.
The goop is to prevent infection from the birth canal getting into baby's eyes.
Locks are necessary to lift barges and canal narrow boats up or down through a series of lock gates. The water level at the start of a series of lock gates may be higher or lower than the water level at the other end of the lock gates. Without the retaining effect of lock gates, the canal would simply be dry in some lengths and wet in others.
A root canal is a procedure that can extend the useful life of a tooth that is infected and would otherwise be lost. If your quality of life or your appearance will not be adversely affected, then a root canal is not absolutely necessary, but the tooth should then be extracted to get rid of the infection. Living with the infection can lead to more serious complications.