Multivariate analysis of oral mucosal ulcers during orthodontic treatment

Table 1 Comparison of the general data of the patients grouped according to the presence and recurrence of oral ulcers

Categories	Indicators	Oral ulcer group, n = 297	Non-oral ulcer group, n = 290	P value	Recurrence group, n = 144	Non-recurrence group, n = 153	P value
Sex	Male	113 (38.05)	236 (81.38)	< 0.001	51 (35.42)	62 (40.52)	0.365
	Female	184 (61.95)	54 (18.62)		93 (64.58)	91 (59.48)
Smoking	No	178 (59.93)	258 (88.9)	< 0.001	93 (64.58)	85 (55.56)	0.113
	Yes	119 (40.07)	32 (11.03)		51 (35.42)	68 (44.44)
Drinking history	No	97 (32.66)	109 (37.59)	0.211	44 (30.56)	53 (34.64)	0.453
	Yes	200 (67.34)	181 (62.41)		100 (69.44)	100 (65.36)
Disease type	Dental caries	152 (51.18)	149 (51.38)	0.484	69 (47.92)	83 (54.25)	0.253
	Dentofacial deformity	72 (24.24)	60 (20.69)		41 (28.47)	31 (20.26)
	Periodontal disease	73 (24.58)	81 (27.93)		34 (23.61)	39 (25.49)
Toothbrush hardness	Soft	151 (50.84)	199 (68.62)	< 0.001	95 (65.97)	56 (36.60)	< 0.001
	Hard	146 (49.16)	91 (31.38)		49 (34.03)	97 (63.40)
Dietary preference for meat	No	218 (73.40)	243 (83.79)	0.002	108 (75.00)	110 (71.90)	0.545
	Yes	79 (26.60)	47 (16.21)		36 (25.00)	43 (28.10)
Dietary temperature	Warm	76 (25.59)	105 (36.21)	0.005	39 (27.08)	37 (24.18)	0.567
	Hot	221 (74.41)	185 (63.79)		105 (72.92)	116 (75.82)
Treatment course	≤ 1 year	84 (28.28)	157 (54.14)	< 0.001	47 (32.64)	37 (24.18)	0.106
	> 1 year	213 (71.72)	133 (45.86)		97 (67.36)	116 (75.82)
Tooth position	Non-anterior tooth region	158 (53.20)	136 (46.90)	0.127	89 (61.81)	69 (45.10)	0.004
	Anterior tooth region	139 (46.80)	154 (53.10)		55 (38.19)	84 (54.90)
Orthodontic appliance type	Straight-wire bracket	138 (46.46)	120 (41.38)	0.215	67 (46.53)	71 (46.41)	0.983
	Conventional straight wire	159 (53.54)	170 (58.62)		77 (53.47)	82 (53.59)
Age	< 60 years	179 (60.27%)	226 (77.93%)	< 0.001	95 (65.97)	84 (54.90)	0.051
	≥ 60 years	118 (39.73%)	64 (22.07%)		49 (34.03)	69 (45.10)
SAS score		44.66 (5.58)	37.31 (5.54)	< 0.001	44.69 (5.67)	44.64 (5.51)	0.940
SDS score		47.04 (7.51)	37.16 (5.15)	< 0.001	47.13 (7.12)	46.96 (7.88)	0.849
Zn		97.95 (20.53)	127.88 (26.83)	< 0.001	98.91 (21.36)	97.05 (19.74)	0.434
Cu		17.04 (6.40)	17.70 (6.03)	0.201	17.15 (6.48)	16.93 (6.35)	0.773
Fe		9.14 (1.50)	9.31 (1.52)	0.158	9.16 (1.49)	9.12 (1.51)	0.830

SAS: Self-Rating Anxiety Scale; SDS: Self-Rating Depression Scale. SAS and SDS scores and the trace element levels are presented as mean (standard deviation), whereas the remaining categories are expressed as the number of patients (percentage).

Table 2 Assignment of values to the variables

Variable	Assigned values
Sex	Male = 1; female = 2
Smoking history	No = 0; yes = 1
Drinking history	No = 0; yes = 1
Tooth brushing frequency	≤ 1 time per day = 0; > 1 time per day = 1
Toothbrush hardness	Soft = 0; hard = 1
Dietary preference for meat	No = 0; yes =1
Dietary temperature	Warm = 0; hot =1
Treatment course	≤ 1 year = 0; > 1 year = 1
Tooth position	Non-anterior tooth region = 0; anterior tooth region = 1
Disease type	Dental caries = 1; dentofacial deformity = 2; periodontal disease =3
Orthodontic appliance type	Straight-wire bracket = 1; conventional straight-wire = 2
Recurrence	Without = 0; with = 1

Table 3 Logistic regression analysis of factors associated with oral ulcers

	Univariate model			Multivariate model
Parameters	OR	95%CI	P value	OR	95%CI	P value
Age
< 60 years	1.000			1.000
≥ 60 years	7.116	4.880–10.377	< 0.001	6.820	2.226–20.893	< 0.001
Smoking history
No	1.000			1.000
Yes	5.390	3.491–8.323	< 0.001	4.434	2.527–7.782	< 0.001
Toothbrush hardness
Soft	1.000			1.000
Hard	2.114	1.510–2.960	< 0.001	2.804	1.746–4.505	< 0.001
Dietary preference for meat
No	1.000			1.000
Yes	1.874	1.250–2.808	0.002	1.719	0.994–2.973	0.053
Dietary temperature
Warm	1.000			1.000
Hot	1.650	1.158–2.351	0.006	1.399	1.220–1.722	0.002
Treatment course
≤ 1 year	1.000			1.000
> 1 year	2.993	2.126–4.215	< 0.001	3.830	2.203–6.659	< 0.001
Sex
Male	1.000			1.000
Female	2.328	1.621–3.343	< 0.001	1.610	0.933–2.780	0.087
Tooth brushing frequency
≤ 1 time per day	1.000			1.000
> 1 time per day	0.309	0.218–0.437	< 0.001	0.228	0.138–0.377	< 0.001
Zn level	0.947	0.938–0.957	< 0.001	0.945	0.927–0.964	< 0.001
SAS score	1.262	1.213–1.314	< 0.001	1.284	1.197–1.378	< 0.001
SDS score	1.278	1.228–1.331	< 0.001	1.322	1.231–1.419	< 0.001

CI: Confidence interval; OR: Odds ratio; SAS: Self-Rating Anxiety Scale; SDS: Self-Rating Depression Scale.

Table 4 Logistic regression analysis of factors associated with oral ulcer recurrence

Indicators	B	SE	Wald	P value	OR	95%CI
Smoking history	1.278	0.344	13.806	< 0.001	3.588	1.829–7.040
Tooth brushing frequency ≤ 1 time per day	1.063	0.352	9.111	0.003	2.894	1.452–5.770
Dentofacial deformity	−0.927	0.350	7.008	0.008	0.396	0.199–0.786
Hard toothbrush	2.067	0.342	36.555	< 0.001	7.905	4.044–15.451
Non-dietary preference for meat	−0.659	0.345	3.639	0.046	0.517	0.263–0.984
Disease in anterior tooth region	0.841	0.334	6.354	0.012	2.319	1.206–4.462

CI: Confidence interval; OR: Odds ratio.