Composite resin is contraindicated as a posterior restorative material in cases of:
1. Allergy to benzoyl peroxide.
2. Bruxism.
3. Lack of enamel at the gingival cavo-surface margin.
4. Inability to maintain a dry operating field.

All of the above.

(1) (2) (3)

(1) and (3)

(2) and (4)

(4) only