Results of the search
Based on search strategies carried out by two (ASM, SD) screened 309 abstracts for inclusion, and assessed 37 publications in full text. Finally, 12 Studies had the eligibility criteria. Studies in English and Persian were included in the study.
Excluded studies
We excluded 25 studies: fifteen had no educational component; six included university students; and four assessed no predefined outcomes (Figure 1).
Duration of follow-up
Follow-up for two studies was one month [17, 18], and for six studies ranged from one month to three months [19-24]; for two studies was from three months to six months [25, 26], and a study was followed up after nine months [27]. In one study, follow-up time was not reported.
Altering knowledge, attitude and behavioral skills can be influenced by short-term educational interventions while changes in goal-oriented behaviors are supported by policies and environments[28]. Thus, within a short time span, mange changes can be made to oral/dental health-related knowledge, knowledge of different oral, oral cavity and material use, attitude, use of tooth brush and floss, visiting a dentist, behavior (alcohol consumption, cigarettes, fluoride toothpaste, delayed brushing of teeth, brushing of teeth with parents). Moreover, long-term effects such as tooth plaque, bleeding gum would take longer time. Post-intervention follow-up has been also considered as a key factor in categorizing the related body of research. It is also noteworthy that in several studies, short-term and long-term variables were taken into account. In such studies, the variable that related to the main consequence was considered. Authors categorized studies covering less than three months as short term and more than three months as long term (Supplement 2).
Some interventions were complex interventions, which involved more than one active component. All educational interventions covered theoretical or practical education sessions, or both, on OH for students. The characteristics of the studies based on the variables studied are described in Table 1.
Table-1: Characteristics of studies Based on the to the variables studied
Author
|
Year
|
country
|
Participant
|
Sample
size
|
Sample size in each group
|
language
|
Ig1
|
Ig2
|
Ig3
|
Ig4
|
Cg
|
Andarkhora et al.
|
2018
|
Iran
|
Primary school
|
90
|
45
|
-
|
-
|
-
|
45
|
Persian
|
Chandrashekar et al.
|
2014
|
India
|
Middle school
|
141
|
36
|
35
|
36
|
-
|
34
|
English
|
Ganapathi et al
|
2015
|
India
|
Middle school
|
200
|
40
|
40
|
40
|
40
|
40
|
English
|
Haleem et al.
|
2012
|
Pakistan
|
Primary school
|
200
|
40
|
40
|
40
|
40
|
40
|
English
|
D'Cruz and Aradhya
|
2013
|
Indian
|
Middle school
|
568
|
141
|
143
|
-
|
-
|
284
|
English
|
Hassani et al.
|
2016
|
Iran
|
Middle school
|
80
|
40
|
-
|
-
|
-
|
40
|
Persian
|
Khudanov et al.
|
2018
|
Uzbekistan
|
High School
|
86
|
42
|
-
|
-
|
-
|
44
|
English
|
Sadana et al.
|
2017
|
Indian
|
Middle school
|
200
|
50
|
50
|
50
|
-
|
50
|
English
|
Mohamadkhah et al.
|
2013
|
Iran
|
Middle school
|
300
|
100
|
100
|
-
|
-
|
100
|
Persian
|
Vangipuram et al.
|
2016
|
India
|
Middle school
|
450
|
150
|
150
|
-
|
-
|
150
|
English
|
Yazdani et al.
|
2009
|
Iran
|
High School
|
388
|
135
|
130
|
-
|
-
|
150
|
English
|
Yang et al.
|
2009
|
Taiwanese
|
High School
|
135
|
67
|
-
|
-
|
-
|
68
|
English
|
Author
|
effects
|
Time point
|
Oral health-related Outcomes
|
Gingival index
|
knowledge
|
attitude
|
behavior
|
Dental plaque
|
DMFT
|
Andarkhora et al.
|
Short-term
|
4w
|
-
|
ü
|
ü
|
ü
|
-
|
-
|
Chandrashekar et al.
|
Short-term
|
3m
|
ü
|
-
|
-
|
-
|
ü
|
ü
|
Ganapathi et al
|
Short-term
|
8w
|
-
|
ü
|
-
|
-
|
ü
|
-
|
Haleem et al.
|
Long-term
|
6m
|
-
|
ü
|
-
|
ü
|
ü
|
-
|
D'Cruz and Aradhya
|
Long-term
|
9m
|
ü
|
ü
|
-
|
ü
|
ü
|
-
|
Hassani et al.
|
Short-term
|
1m
|
-
|
ü
|
ü
|
ü
|
-
|
-
|
Khudanov et al.
|
Short-term
|
2m
|
-
|
ü
|
ü
|
ü
|
-
|
-
|
Sadana et al.
|
Short-term
|
1.5m
|
-
|
ü
|
-
|
-
|
-
|
ü
|
Mohamadkhah et al.
|
Short-term
|
3m
|
-
|
ü
|
ü
|
ü
|
-
|
-
|
Vangipuram et al.
|
Long-term
|
6m
|
ü
|
ü
|
-
|
ü
|
ü
|
-
|
Yazdani et al.
|
Short-term
|
3m
|
ü
|
-
|
-
|
-
|
ü
|
-
|
Yang et al.
|
-
|
N /R
|
-
|
ü
|
ü
|
ü
|
-
|
-
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Included studies
We included five individual RCTs [20-22, 26, 27], four cluster-RCTs [19, 24, 25, 29], and three Quasi- experimental [17, 18, 23] with 2838 students as participants.
The existing body of research explored the variety of educational content and methods. The interventions were described in oral/dental health pamphlets and instructions. The educational methods involved lecture, album, slides, films, pamphlets, booklets, dental educational models, PowerPoint presentations, role-play, use of tooth brush under the supervised tooth brushing system and group discussions. Moreover, teachers, peers and dentists were involved in the transfer of educational information (Table 2).
Table 2: The main findings of studies reviewed
Author
|
Study Design
|
Model of delivery
|
group
|
Outcomes assessed1
|
Andarkhora et al.
|
Quasi-experimental*
|
Film, lecture
|
Ig1: lecture
|
K, A, B
|
Ig2: Multi Media
|
Control group
|
Chandrashekar et al.
|
Cluster- RCTS
|
Brochure, demonstration the model
|
Ig1: DHE by a qualified Dentist + using the
audio-visual aids
|
PI, DMFT, GI
|
Ig2: DHE by the
trained school teachers
|
Ig3: DHE by the trained school teachers
+ oral hygiene aids (tooth brush and tooth
paste)
|
Control group
|
Ganapathi et al
|
RCTS
|
Audio record, pamphlets
|
Ig1: Audio record
|
K, PI
|
Ig2: Pamphlets
|
Ig3: Tooth models
|
Ig4: Multisensory
|
Control group
|
Haleem et al.
|
Cluster- RCTS
|
Booklet supplemented, session
|
Ig1: Dentist-led
|
K, B, PI
|
Ig2: Teacher-led
|
Ig3: Peer-led
|
Ig4: Self-learning
|
Control group
|
D'Cruz and Aradhya
|
RCTS
|
Pamphlets, demonstration the model
|
Ig1: A lecture using a PowerPoint presentation
|
K, B, PI, GI
|
Ig2: lecture, a demonstration of the tooth brushing method
|
Control group
|
Hassani et al.
|
Quasi-experimental
|
Booklet, CD, session
|
I g
|
K, A, P
|
Control group
|
Khudanov et al.
|
RCTS
|
Lesson, lecture, messages, demonstrational models
|
I g
|
K, A, P
|
Control group
|
Sadana et al.
|
RCTS
|
Audio record, pamphlets
|
Ig1: verbal communication
|
K, DMFT
|
Ig2: verbal communication and self-educational pamphlets
|
Ig3: audiovisual aids and verbal communication
|
Control group
|
Mohamadkhah et al.
|
Quasi-experimental
|
Film, lecture
|
Ig1: film Group
|
K, A, P
|
Ig2: lecture Group
|
Control group
|
Vangipuram et al.
|
RCTS
|
Power point presentation, chalk and talk presentation, using charts, posters, booklets and tooth brushing demonstration models
|
Ig1: peer Group
|
K, B, PI, GI
|
Ig2: dentist Group
|
Control group
|
Yazdani et al.
|
Cluster- RCTS
|
Leaflet, Videotape
|
Ig1: Leaflet Group
|
PI, GI
|
Ig2: Videotape Group
|
Control group
|
Yang et al.
|
Cluster- RCTS
|
lectures, role-playing, small group discussion and group contests
|
Intervention group
|
K, A, B
|
Control group
|
Outcomes assessed1: K (knowledge), A (Attitude), B (behavior), PI (Plaque index), GI (Gingival Index), DMFT (decayed, missed, filled permanent tooth). *Quasi-experimental research involves the manipulation of an independent variable without the random assignment of participants to conditions or orders of conditions.
Overall risk of bias
The presentation of the assessments of the risk of bias was done based on Figure 2, using Review Manager 2014 software. None of the studies reported low risk of bias. A high risk of bias in assessment of risk of bias was observed in eight studies [17, 18, 20, 23-27]. The other four studies were at unclear risk of bias [19, 21, 22, 27, 29].
Measured outcomes
Statistical heterogeneity of studies was assessed through the calculation of tau2 and I2. As the heterogeneity of studies s was higher than 25%, a random effects model was applied.
Oral health-related knowledge
Based on the results, ten studies reported oral health-related knowledge of students [17, 18, 20-23, 25, 27, 29]; all studies Oral health-related knowledge assessed by self-administered questionnaires. Data of twelve studies on students’ knowledge were combined in the current study. Moreover, ten studies at high and unclear risk of bias including 2309 members of students were combined in a meta-analysis. Oral health knowledge scores improved significantly more among students receiving the oral health educational intervention compared with students that no receive educational activities (SMD 3.31, 95% CI 2.52 to 4.11; I2 = 98; P < 0.001) (Figure 3).
Oral health-related attitude
Oral health-related attitude of students was evaluated by six studies [17, 18, 21, 23]. Self-administered questionnaires were applied with Likert scale. Self-administered questionnaires were applied with Likert scale. Six studies including 1141 members of students were combined in a meta-analysis by the authors. Oral health attitude scores improved significantly more among students receiving the oral health educational intervention compared with students that no receive educational activities (SMD 1.99, 95% CI 0. 43 to 3.54; I2 = 99; P < 0.001) (Figure 4).
Oral health-related behavior
Oral health-related behavior of students was evaluated by eight studies [17, 18, 21, 23, 25, 27]. Eight studies including1909 members of students were combined in a meta-analysis by the authors. OH behavior scores improved significantly more among students receiving the oral health educational intervention compared with students that no receive educational activities (SMD 4.74, 95% CI 3.70 to 5.77; I2 = 99; P < 0.001) (Figure 5).
Dental plaque index
We meta-analyzed six studies [19-22, 24-27] and involving 1947 students. Dental plaque scores improved significantly more among students receiving the oral health educational intervention compared with students that no receive educational activities (SMD -1.01, 95% CI -1.50 to -0. 51; I2 = 97; P < 0.001) (Figure 6).
Gingival index
Authors meta-analyzed four studies [19, 24, 26, 27] and involving 1541 students. Gingival scores improved significantly more among students receiving the oral health educational intervention compared with students that no receive educational activities (SMD 0. 33, 95% CI -0. 36 to 1. 02; I2 = 98; P = 0.34) (Figure 7).