Table 1.

The main factors affecting veneer fractures, with examples.

Factor	Examples
Inappropriate case selection	Unfavorable occlusion [9].
	Endodontically treated teeth [7].
	Patient with inherent parafunctionality, e.g., grinding (ice cubes), biting (nail and pencil), bruxism [7].
Improper material selection	Selection of resin cements with a low modulus of elasticity [10].
	Selection of a material with a low flexural strength (feldspathic porcelain) for cases that need a high strength, e.g., lingually tilted teeth, diastema closure, and/or correction of malformed anterior teeth [11].
Improper communication with the dental laboratory	Thicker veneer [12] and incorrect ratio of veneer thicknesses to die spacer (the die spacer thickness must not be more than 1/3 of the veneer thickness to prevent debonding or fracture) [13].
Improper preparation design	Sharp angles or inadequate tooth reduction; extension of the preparation to the palatal surface [9]; incisal coverage for maxillary canine [14]; not restoring a cavity to obtain a thick cement layer [12]; labial thicknesses of ultrathin veneers should be 0.5/0.4 mm for premolar teeth [15].
Improper cementation procedure	Improper veneer handling, especially for fragile feldspathic veneers.
	Incomplete polymerization using light-cure based resin cements for thick (>1 mm) opaque cement and opaque veneer (e.max MO *, HO *, zirconia) [16,17].
	Inappropriate finishing and polishing, leading to cracks [18].
Improper occlusion for post laminate veneer delivery	Inappropriate occlusion in centric relation, protrusive, and canine guided movements [14].

* MO = medium opacity, HO = high opacity.