Table 6.

Results of null hypotheses testing

Results of null hypotheses testing (significance level p < 0.01)
Null hypotheses	p Value	Observational study (n/total)	Experimental study (n/total)
Study design is not associated with the fact that success, survival, and failures were well defined	0.956 (Survival)	13/77	10/58
	0.415 (Success)	16/36	10/29
	0.006 (Failure)	40/90	14/62
Study design is not associated with the lack of use of analytical methods for assessment of survival, success, and failure	0.583	36/105	29/77
Study design is not associated with the type of setting used (private practice vs university)	0.213	34 (Private) & 64 (University) /98	16 (Private) & 47 (University) /63
Study design is not associated with the patient descriptors	0.003	78/105	41/77
Study design is not associated with the tooth descriptor	<0.001	23/105	3/77
Study design is not associated with the description of tooth preparation included in the paper	<0.001	28/105	61/77
Study design is not associated with the type of material used	<0.001 (all-ceramic)	42/105	65/77
	<0.001(PFM)	44/105	10/77
Study design is not associated with the use of the standardized criteria to assess restoration	<0.001	32 /105	54 /77
		Group 1(n)/ Total	Group 2(n)/ Total
The proportions of recording definitions for fixed prosthodontic outcomes (i.e., survival, success, and failure) is the same for groups 1* and 2**	0.267 (Survival)	6/48	15/74
	0.156 (Success)	10/32	16/33
	0.339 (Failure)	24/76	30/77
The proportions of reporting of methods used to analyze outcomes is the same for groups 1 and 2	<0.001	44/83	21/91
The proportions of type of setting used is the same for groups 1 and 2 (private practice vs. university)	0.020	49/81	62/80
The proportions of reporting patient descriptors is the same for groups 1 and 2	0.326	62 /90	57 /92
The proportions of reporting tooth descriptors is the same for groups 1 and 2	0.002	20/90	6/92
The proportions of reporting detailed tooth preparation is the same for groups 1 and 2	0.005	37/90	57/92
The proportions of using different types of restorative materials is the same for groups 1 and 2	0.003 (all-ceramic)	43/90	64/92
	0.923 (PFM)	27/90	27/92
The proportions of reporting the use of standardized criteria is the same for groups 1 and 2	0.453	40/90	46/92
The proportions of experimental studies and observational studies measuring fixed prosthodontics outcomes is the same for groups 1 and 2	0.128	33 (experimental) & 57 (observational)/90	44 (experimental) & 48 (observational) /92

^*Group 1 (Literature published up to the end of December 2004).

^**Group 2 (Literature published from January 2005 until July 2012).