TABLE 1.

Proportion of cracked teeth by tooth type from 12 clinical studies.

Study author	Tooth type	Incidence rate (%)	Total teeth	% unrestored	Average age
Abou-Rass, 198318	Mandibular molars	45.8	120	15.8
	Maxillary molars	20.8
	Mand. premolars	0
	Max. premolars	19.2
	Other	14.2
Bader et al., 200114	Mandibular molars	36.3	377
	Maxillary molars	22
	Mand. premolars	6.9
	Max. premolars	20.4
	Other	14.3
Brynjulfsen et al., 200264	Mandibular molars	28.3	46
	Maxillary molars	39.1
	Mand. premolars	4.3
	Max. premolars	28.3
	Other	0
Cavel et al., 198515	Mandibular molars	44.9	118	4.2
	Maxillary molars	25.4
	Mand. premolars	5.1
	Max. premolars	24.6
	Other	0
Cameron, 19645	Mandibular molars	54	50
	Maxillary molars	28
	Mand. premolars	2
	Max. premolars	16
	Other	0
Cameron, 19769	Mandibular molars	66.7	102
	Maxillary molars	23.5
	Mand. premolars	0
	Max. premolars	9.8
	Other	0
Eakle et al., 198610	Mandibular molars	43.2	206	8.7	37.6
	Maxillary molars	25.73
	Mand. premolars	25.24
	Max. premolars	5.83
	Other	0
Hiatt, 197329	Mandibular molars	70	100	35	40–49
	Maxillary molars	19
	Mand. premolars	10
	Max. premolars	1
	Other	0
Krell and Rivera, 200749	Mandibular molars	59.6	796
	Maxillary molars	29.9
	Mand. premolars	1.6
	Max. premolars	8.9
	Other	0
Lagouvardos et al., 198965	Mandibular molars	46.5	200		25–48
	Maxillary molars	20
	Mand. premolars	5
	Max. premolars	28.5
	Other	0
Roh et al., 200612	Mandibular molars	36.4	154		40–49
	Maxillary molars	57.1
	Mand. premolars	1.9
	Max. premolars	4.6
	Other	0
Talim and Gohil, 19748	Mandibular molars	45
	Maxillary molars	22.5
	Mand. premolars	7.5
	Max. premolars	25
	Other	0