DP Chemistry (last assessment 2024)
Question 17N.3.sl.TZ0.b.ii
| Date | November 2017 | Marks available | [Maximum mark: 1] | Reference code | 17N.3.sl.TZ0.b.ii |
| Level | sl | Paper | 3 | Time zone | TZ0 |
| Command term | Suggest | Question number | b.ii | Adapted from | N/A |
b.ii.
[Maximum mark: 1]
17N.3.sl.TZ0.b.ii
It is wise to fill dental cavities before irreversible tooth decay sets in. An amalgam (alloy of mercury, silver, and other metals) is often used although many prefer a white composite material.
At present, composite fillings are more expensive than amalgam fillings.
Suggest why a patient might choose a composite filling.
[1]
Markscheme
concern about Hg poisoning
OR
«composite» is white «so looks more like tooth»
OR
galvanic response potential exists
OR
local allergic potential
OR
less damage/destruction of healthy tooth tissue
OR
long term corrosion requires replacement
OR
gradual darkening of tooth
Accept other correct responses.
