Enamel decalcification around and under orthodontic appliances have been known as
a significant clinical problem, in fact an orthodontic patient is a high risk person.
Whether this high risk due to oral hygiene related to orthodontic appliance or as a
cause of phosporic acid contained in zinc oxyphosphate cement that have been
commonly used to bracket adhesion. The purpose of this article was to provide a
description of enamel decalcification process and prevention of decalcification
following orthodontic treatment. Prevention of enamel decalcification following
orthodontic treatment can be performed by polishing tooth surface after treatment,
using tooth paste contained fluoride, rinsing, maintenance good oral hygiene, tooth
brushing, and other additional oral hygiene method.

The use of fixed partial denture (FPD) nowdays has been very popular in our society.
This is due to their smaller size, and more convenient to be used and fixed in the
mouth. The choice of nickel chromium (NiCr)as the metal component of FPD is
based on its character of corrosion proof, light, and hard. However, nickel contained
can be allergic. Allergic reactions reported, vary from oedema of tongue and lip, and
mouth lining until anaphylaxis. These reactions are related to the pattern and
corrosion modes, followed by the release of metalic ions like nickel into the oral
cavity. This depends not only on the composition of metal, but also the temperature
and pH of the oral cavity. Some studies have reported the use of NiCr might cause
inflammation reaction of periodontal tissue.