Table 4.

Repeated measures analysis of changes in health complaints over time. Per-protocol (PP) and intention-to-treat (ITT) repeated measures analysis of changes in health complaints in the treatment group and the reference group. Mean index scores, standard deviations (s.d.) and P-values for within-group changes over time are given

		Questionnaire 1	Pre-treatment examination	3-month follow-up	1-year follow-up†	3-year follow-up‡
	n	Mean (s.d.)	Mean (s.d.)	Mean (s.d.)	Mean (s.d.)	Mean (s.d.)	P-value*
Treatment group
Intra-oral index (PP)	18	8·6 (6·9)	6·6 (3·8)	6·7 (4·5)	4·7 (5·2)	5·2 (3·8)	0·026
Intra-oral index (ITT)	20	8·4 (6·6)	6·8 (3·7)	6·4 (4·5)	4·8 (5·0)	4·9 (3·8)	0·015
Extra-oral index (PP)	18	6·7 (8·8)	6·7 (7·1)	5·7 (6·4)	2·4 (3·2)	4·8 (4·3)	0·004§
Extra-oral index (ITT)	20	6·9 (8·4)	6·8 (6·8)	5·6 (6·3)	2·8 (3·8)	4·9 (4·4)	0·009§
General index (PP)	18	41·4 (16·4)	42·9 (21·3)	39·0 (24·3)	32·1 (19·2)	31·6 (14·5)	0·001
General index (ITT)	20	41·5 (16·0)	42·7 (20·4)	37·9 (23·2)	31·6 (18·5)	31·4 (13·9)	<0·001
Reference group
Intra-oral index (PP)	12	11·0 (12·0)	n.a.	n.a.	10·8 (12·8)	15·4 (13·4)	0·245§
Intra-oral index (ITT)	20	13·0 (12·0)	n.a.	n.a.	11·3 (12·4)	13·6 (12·2)	0·246§
Extra-oral index (PP)	12	10·8 (10·6)	n.a.	n.a.	9·4 (11·4)	12·5 (12·6)	0·179§
Extra-oral index (ITT)	20	11·0 (9·3)	n.a.	n.a.	10·0 (10·0)	11·6 (10·8)	0·259§
General index (PP)	12	43·1 (18·1)	n.a.	n.a.	38·3 (23·3)	49·5 (28·5)	0·004§
General index (ITT)	20	47·3 (21·2)	n.a.	n.a.	41·3 (25·2)	49·6 (27·3)	0·004§

n.a., not applicable.

^*P-value from analysis of variance for repeated measures.

^†For the reference group, mean index scores from Questionnaire 2 were used.

^‡For the reference group, mean index scores from Questionnaire 3 were used.

^§Wilks’ Lambda.