SIST-TP CEN/TR 16918:2016
(Main)Safety of toys - Children´s mouthing behaviour in contact with toys
Safety of toys - Children´s mouthing behaviour in contact with toys
This Technical Report presents the results of a European Study on “Children's mouthing behaviour in contact with toys”. It provides statistical data on the duration and frequency that children under 36 months introduce toys into their mouths and estimated data on the time children under 36 months spend mouthing toys each day.
Furthermore, it provides information on:
- the literature focused on children's mouthing behaviour, including commonly used methodologies and significant results;
- the design and methodology of the study;
- the data on the children and toy sample;
- the forms used in data collection.
Sicherheit von Spielzeug - Mundkontaktverhalten von Kindern
Sécurité des jouets - Analyse de la mise à la bouche des jouets par les enfants
Varnost igrač - Obnašanje otroka pri stiku igrače z usti
To tehnično poročilo predstavlja rezultate evropske študije »Obnašanje otroka pri stiku igrače z usti«. Podaja statistične podatke o trajanju in pogostosti, s katero otroci, mlajši od 36 mesecev, v usta vnašajo igrače, ter ocenjene podatke o času, ki ga otroci, mlajši od 36 mesecev, vsak dan namenijo stiku igrač z usti.
Nadalje podaja informacije o
- literaturi, ki se osredotoča na obnašanje otrok, povezano z usti, vključno z najpogosteje uporabljanimi metodologijami in pomembnimi rezultati;
- zasnovi in metodologiji študije;
- podatkih o otrocih in vzorcu igrač;
- obrazcih, uporabljenih za zbiranje podatkov.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2016
9DUQRVWLJUDþ2EQDãDQMHRWURNDSULVWLNXLJUDþH]XVWL
Safety of toys - Children´s mouthing behaviour in contact with toys
Sicherheit von Spielzeug - Mundkontaktverhalten von Kindern
Sécurité des jouets - Analyse de la mise à la bouche des jouets par les enfants
Ta slovenski standard je istoveten z: CEN/TR 16918:2015
ICS:
97.200.50 ,JUDþH Toys
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
CEN/TR 16918
TECHNICAL REPORT
RAPPORT TECHNIQUE
December 2015
TECHNISCHER BERICHT
ICS 97.200.50
English Version
Safety of toys - Children´s mouthing behaviour in contact
with toys
Sécurité des jouets - Analyse de la mise à la bouche des Sicherheit von Spielzeug - Mundkontaktverhalten von
jouets par les enfants Kindern
This Technical Report was approved by CEN on 7 December 2015. It has been drawn up by the Technical Committee CEN/TC 52.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16918:2015 E
worldwide for CEN national Members.
Contents Page
European foreword . 5
Introduction . 6
1 Scope . 7
2 Literature review . 7
2.1 General . 7
2.2 Methodological review on children’s mouthing behaviour . 8
2.3 Main results on the duration and frequency of children’s mouthing behaviour in
previous literature . 11
2.3.1 General . 11
2.3.2 Daily time available to mouth not spent sleeping or eating . 12
2.3.3 Frequency of mouthing objects . 13
2.3.4 Amount of the time spent mouthing objects . 14
3 Design of the research . 16
3.1 General objective. 16
3.2 Data collection . 16
3.3 Methodology . 17
3.3.1 General . 17
3.3.2 Ethnographic. 18
3.3.3 Home environment . 18
3.3.4 Free play environment . 20
3.3.5 Pilot test . 21
3.3.6 Observational tool and protocols . 22
3.3.7 Training sessions . 23
3.4 Sample description: Children and toys . 23
3.4.1 General . 23
3.4.2 Children sample . 24
3.4.3 Sample . 31
3.5 Statistical analysis . 35
4 Results of children’s mouthing behaviour in contact with toys . 36
4.1 Frequency children mouthed toys . 36
4.1.1 General . 36
4.1.2 By age . 36
4.1.3 By gender . 37
4.1.4 By gender and age . 38
4.1.5 By country . 39
4.1.6 By country and age . 40
4.2 Time children spent mouthing toys . 41
4.2.1 General . 41
4.2.2 By age . 41
4.2.3 By gender . 42
4.2.4 By gender and age . 42
4.2.5 By country . 43
4.2.6 By country and age . 44
4.2.7 Toy-to-mouth contact duration by age . 45
4.3 Type of mouthing: lip/tongue, suck/engulf, bite/chew . 47
4.3.1 Frequency by type of mouthing . 47
4.3.2 Frequency by type of mouthing and age. 48
4.3.3 Time children spent mouthing, by type of mouthing . 49
4.3.4 Time children spent mouthing toys by type of mouthing and age . 50
4.4 Elastomeric vs. not elastomeric material . 51
4.4.1 General . 51
4.4.2 Frequency by elastomeric and not elastomeric material . 51
4.4.3 Frequency by elastomeric and not elastomeric material and age . 52
4.4.4 Time children spent mouthing by elastomeric and not elastomeric material . 53
4.4.5 Time children spent mouthing, by elastomeric and not elastomeric material and age . 53
4.4.6 Toy-to-mouth contact duration by elastomeric and not elastomeric material . 54
4.4.7 Toy-to-mouth duration by elastomeric and not elastomeric material and age . 55
4.4.8 Qualitative approach of the influence of elastomeric material in children’s mouthing
behaviour. 55
4.5 Toys intended vs not intended to be mouthed . 58
4.5.1 General . 58
4.5.2 Frequency children mouthed toys intended vs not intended to be mouthed . 58
4.5.3 Frequency children mouthed toys intended vs not intended to be mouthed by age . 59
4.5.4 Time children spent mouthing toys intended vs not intended to be mouthed . 60
4.5.5 Time children spent mouthing toys intended vs not intended to be mouthed by age . 60
4.5.6 Toy-to-mouth contact duration for toys intended vs not intended to be mouthed . 61
4.5.7 Toy-to-mouth contact for toys intended vs not intended to be mouthed by age . 62
4.6 Toy categories . 63
4.6.1 General . 63
4.6.2 Frequency children mouthed toys by toy category . 64
4.6.3 Time children spent mouthing toys by toy category . 65
4.7 Bite marks left on toys . 66
4.8 Degree of salivation . 67
4.8.1 General . 67
4.8.2 Toys that contributed to high degrees of salivation . 68
5 Estimations . 69
5.1 General . 69
5.2 Results of ethnographic study . 69
5.2.1 Time children are awake and not eating. 69
5.2.2 Time children are in contact with toys . 71
5.3 Estimation formula . 72
5.4 Estimation of frequency children mouth toys . 72
5.4.1 General . 72
5.4.2 Estimation of frequency children mouth toys by age . 73
5.5 Estimation of time children spend mouthing toys. 74
5.5.1 General . 74
5.5.2 Estimation of time children spend mouthing toys by age . 75
6 Discussion. 76
6.1 Frequency children mouthed toys . 76
6.2 Time children spent mouthing toys . 77
6.3 Time available to mouth toys per day . 78
6.4 Type of mouthing . 80
6.5 Elastomeric toys . 80
6.6 Toys intended and not intended to be mouthed . 80
6.7 Mouthing toys by categories . 80
6.8 Bite marks left on toys . 81
6.9 Degree of salivation . 81
7 Summary . 81
7.1 Introduction . 81
7.2 Literature review . 81
7.3 Design of the research . 82
7.4 Results . 82
7.4.1 Frequency children mouthed toys . 82
7.4.2 Time spent mouthing toys . 82
7.5 Estimations . 83
7.5.1 The frequency children mouthed toys . 83
7.5.2 Time spent mouthing toys . 83
7.6 Childcare articles . 83
Annex A (informative) Summary of previous quantitative studies on children’s mouthing
behaviour . 84
Annex B (informative) Results of children’s mouthing behaviour in contact with childcare
articles . 92
B.1 Introduction . 92
B.2 Design of the research . 92
B.3 Frequency children mouthed childcare articles . 96
B.4 Time children spent mouthing childcare articles . 98
B.5 Type of mouthing lip/tongue, suck/engulf, bite/chew . 102
B.6 Childcare article category . 105
B.7 Summary . 105
Annex C (informative) Statistical results . 107
C.1 Normal distribution test . 107
C.2 Significance test . 109
C.3 Mean weighted by year . 123
C.4 Observational periods . 128
Annex D (informative) Glossary of terms and definitions . 130
Bibliography . 132
European foreword
This document (CEN/TR 16918:2015) has been prepared by Technical Committee CEN/TC 52 “Safety of
toys”, the secretariat of which is held by DS.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
Introduction
This CEN Technical Report presents the results of a European Study on “Children's mouthing behaviour
in contact with toys”. The objective of the study was the measurement and quantification of the
duration and frequency that children under 36 months introduce toys into their mouths spontaneously.
It presents information about the literature review focused on children's mouthing behaviour, including
commonly used methodologies in addition to a review of significant results from previous research. It
also includes the design of the research; methodology; data on the children and toy sample; complete
results obtained in the frequency and duration that children mouthed toys and estimated data on the
time children under 36 months spend mouthing toys each day.
Up to now, the study was the one with the largest sample (245 children and a total number of 1 680
observations) and the only one to be carried out in three different European countries (Germany,
France and Spain). It was also the study with the highest representation of specific toys (54 different
products) for children up to 36 months.
In addition to the results on the mouthing behaviour with regard to toys, Annex B contains information
concerning children's mouthing behaviour in contact with childcare articles. This informative annex is,
however, just a first approach, and of limited value.
Clause 7 of this CEN Technical Report contains a more detailed summary of the results of the European
Study on “Children's mouthing behaviour in contact with toys”.
1 Scope
This Technical Report presents the results of a European Study on “Children's mouthing behaviour in
contact with toys”. It provides statistical data on the duration and frequency that children under
36 months introduce toys into their mouths and estimated data on the time children under 36 months
spend mouthing toys each day.
Furthermore, it provides information on:
— the literature focused on children's mouthing behaviour, including commonly used methodologies
and significant results;
— the design and methodology of the study;
— the data on the children and toy sample;
— the forms used in data collection.
2 Literature review
2.1 General
Mouthing is an important component in childhood development. In early development, sucking
provides essential nutrients in the form of breast or bottle-feeding, as well as a feeling of well-being and
a sense of security (Juberg et al., 2001 [1]). If infants are not allowed unrestricted breast-feeding, they
will suck on a dummy, thumb (or other fingers), blanket, or toy (Groot et al., 1998 [2]). As children
develop, mouthing behaviour, in combination with looking and touching, allows children to explore and
investigate their environment. Mouthing behaviour develops into an exploratory behaviour in which
objects are placed into the mouth for a few seconds for purposes of discovery. During this stage of
development, children will put their hands, and any object that they come in contact with, into their
mouths (Ruff, 1984 [3]; Ruff and Dubiner, 1987 [4]; Davis et al., 1995 [5]; Groot et al., 1998 [2]: Tulve et
al., 2002 [6]).
In the field of psychology, Freud named the stage between birth and 2 years of age the 'oral stage'. This
first stage of development is characterized by the physical aspects of sucking, encompassed by the
mouth, tongue and lips. During the oral stage, it is common for children to have a persistent tendency to
put whatever falls into their hands into their mouths. It is the means by which they express their need
to experience the world through their mouths. The pleasurable activity of sucking, biting and chewing,
means the child starts to recognize objects and distinguish them as separate from himself. When a baby
puts something in his mouth, he bites it with his gums, sucks it and moves it with his tongue. It is the
first form of learning that children experience, as they begin to recognize textures, temperatures and
forms through mouthing. Furthermore, it benefits verbalization processes, chewing and teething.
Teething is another reason that children will mouth fingers and objects. At this stage of development,
mouthing alleviates the pain and discomfort associated with teething (Groot et al., 1998 [2]). Teething
usually begins at 6 months to 8 months, but may start several months earlier or later. Teething
continues in babies until approximately the age of 3.
The first teeth to appear are usually the two bottom front teeth, also known as the lower front incisors.
Between 4 weeks to 8 weeks later, they are followed by the four upper front teeth. About a month later,
the lower lateral incisors appear. Next come the first molars, and then finally the canines. Most children
have their 20 milk teeth (which are the first teeth to appear) when they reach three years of age. The
commencement of teething is the most important stage in babies' mouthing.
Young children's urge to suck and mouth is a natural developmental phase. Sucking may be divided into
two distinct behavioural types: nutritive and non-nutritive sucking (Turgeon-O'Brien et al., 1995 [7]).
Nutritive sucking is the instinctive need to feed. Non-nutritive sucking (e.g. sucking on a
dummy/soother) is thought to be adopted by infants as a response to frustration, or as a need for
contact, or as a part of the child's psychological development in exploring the world around them
through touching and tasting objects with the mouth and tongue (Norris and Smith, 2002 [8]).
Research on the mouthing behaviour of children has usually concentrated on the psychological
development of the act, being concerned with the cause and motivation behind mouthing. There is,
however, a child safety issue concerned with the safety of the items being placed into the mouths of
young children. Some products, such as dummies, teething rings and bottle teats, are intended to be
placed into the mouth. Unfortunately, products not intended for mouthing invariably end up in
children's mouths, as this is how young children explore their world. Obviously, child safety is of
paramount concern, and so products shall be as safe as possible, whether they are handled or placed
into the mouth (Smith and Norris, 2003 [9]).
This is the reason why there is an increasing focus on children in exposure and risk assessments, as
they are more sensitive to environmental contaminants than adults (Silvers et al., 1994 [10]). All items
that are placed into a child's mouth have the potential to be a mechanical hazard. The most obvious
hazards are choking or suffocation, although there is a risk of any item becoming stuck in the mouth and
the resultant trauma may be serious. There is also the risk of foreign body incidents where a child
swallows an item, which may then cause harm to internal systems of the body (Norris and Smith, 2002
[8]).
Because of their mouthing behaviour, children have a higher potential for exposure to available
chemicals through the non-dietary ingestion route; thus, frequency of hand-to-mouth activity is an
important variable for exposure assessments. Such data are limited and difficult to collect. Few
published studies report such information, and the studies that have been conducted used different
data collection approaches: e.g. videography vs. real-time observation, data analysis and reporting
methods, ages of children, locations (indoor vs. outdoor), and even definitions of “mouthing” (Xue et al.
2007 [11]).
As children in all geographic regions spend most of their time indoors, at home, Silvers et al. (1994) [10]
indicated that risk assessments should focus on indoor, on-site hazards. The same conclusion was made
by Xue et al. (2007) [11], as was seen in the review of previous research. The present study is consistent
with these conclusions: observing interaction with a sample of toys in the home environment (indoor
parental observation). Furthermore, Hubal et al. (2000) [12] defined the general principles for studying
children's exposure. In their review of factors in the Children's Exposure Assessment, they indicated
that exposure assessments are developed to represent real-life situations.
Toxic chemicals can be transferred from contaminated surfaces or soil to the hand and then ingested via
hand-to-mouth activity. Detailed information on children's mouthing activities helps researchers assess
children's exposure to toxicants via the non-dietary ingestion route. Thus the frequency of hand-to-
mouth behaviour is an important variable for children because, as part of their natural development,
children mouth their fingers and other objects (Hubal et al. 2000 [12]).
2.2 Methodological review on children’s mouthing behaviour
Generally, children's mouthing behaviour is studied using both direct observation and video recording
methodologies (Zartarian et al., 1996 [13]; Reed et al., 1999 [14]; Freeman et al., 2001 [15]; Ferguson et
al., 2005 [16]). Data analyses from these studies are reported as either a frequency of contact (i.e.
contacts/duration) or as an exposure period (i.e. minutes). Xue et al. (2007) [11] studied the frequency
of hand-to-mouth contact; this research will also analyse hand-to-mouth duration data.
The general formula for estimating non-dietary ingestion of chemical residue via hand-to-mouth
contact involves the product of hand residue or soil loading (µg/cm or µg/g), hand-to-mouth frequency
(contacts/h), hand surface mouthed per mouthing event (cm ) and exposure duration (h/ day) (Norris
and Smith, 2002 [8])
The statistical formula used by Norris and Smith (2002) [8], in which the estimated daily mouthing time
is extrapolated from the mouthing behaviour recorded over the observation time, is calculated as
follows:
t
omt
tt⋅ (1)
edmt tamp
t
tto
where
t estimated daily mouthing time;
edmt
t observed mouthing time (amount of mouthing time recorded for each child);
omt
t total time observed (time available over the whole day for the child to mouth);
tto
t time available to mouth per day.
tamd
Norris and Smith [8] calculated the average time spent mouthing per hour, multiplied by the total
number of hours each day that each child has available to mouth; i.e. the number of hours they are
awake during the day but not eating, or the number of hours they are awake and in contact with a toy
(play time). This is based on the assumption that children are likely to mouth at the same rate
throughout the day. They performed a Krustal-Wallis test, which showed no significant differences in
observed mouthing between the different times of the day when children were observed.
Children's hand-to-mouth behaviour is difficult to measure for several reasons. Some of these reasons
include the following: children's contact with surfaces and objects are frequent and intermittent;
observational studies are labour-intensive for data collection and data analysis; and data analysis can
be subjective. Interpretation of the results is also difficult. Some researchers express mouthing
behaviour in terms of frequency of occurrence, others express mouthing behaviour as an exposure
period (Xue et al., 2007 [11]).
Table 1 summarizes previous literature, focused on the types of activity collected by the various authors
and the methodology used in their research, in order to have a complete picture of the methodological
approaches used in the study of children's mouthing behaviour.
Table 1 — Summary of previous literature
Reference Age Number of Location of Activity collected Method employed
Range children study collection
AuYeung, 1 year to 38 California Detailed information on Videotaping for 2 h per
W. et al. 6 years children’s mouthing child during natural
(2004) [17] activities. play time.
Norris and 1 month 236 London, Duration of each mouthing 5 h of observation in
Smith to 5 years United behaviour. periods of 15 min
(2002) [8] Kingdom
What types of items were
mouthed.
The type of mouthing
behaviour for each item
mouthed.
What was mouthed and in
which room of the house.
Black et al. 7 months 52 Texas Hand-to-mouth Questionnaires to
(2004) [18] to parents. Videotaping
Object-to-mouth
53 months children for 4 h using a
Food-handling
hand-held camcorder.
Children were followed
through the house and
yard.
=
Reference Age Number of Location of Activity collected Method employed
Range children study collection
Ferguson et 1 year to 83 Salinas MLATS, describing Videotaping human
al. (2005) (4 studies: intermittent dermal (i.e. a activity to assess
12 years Valley
[16] 4–23–20– second-by-second account exposure. 4 h/day to
Menlo Park
36) of contact with surfaces 8 h/day (sample 4
and Palo
and objects) and non- children) 2 h (sample
Alto,
dietary ingestion contact 36 children) 2 h
California
behaviour. (sample 20 children)
Freeman 3 years to 19 Minnesota Mouthing behaviour Videotaping
(2000, 12 years observations
2001) [19]
Groot et al. 3 months 42 The Mouthing duration Parental Observation
(1998) [2] to Netherlands 2,5 h/day of 15 min
36 months periods
Juberg et al. 0 months 168 Western Mouthing duration, Parental Observation;
(2001) [1] to New York mouthing behaviour 1 day; standard diary
36 months form
Madden et 23 months 3 Urban Mouth-to-body, mouth-to- Trained observers 3 h
al. (1980) to Maryland object to 6 h of observation;
[20] 33 months recorded mouthing
activity; given a score
based on frequency
Reed et al. 2 years to 30 Urban New Hand-to-clothing, hand-to- Videotaping waking
(1999) [14] 6 years Jersey dirt, hand-to-hand, hand- hours: approximately 1
to-mouth, hand-to-object, day of tape per child;
hand-to-other items activities were
(paper, grass, pets), hand- quantified from 5-min
to-smooth/textured periods and added up to
surfaces, object-to-mouth give hourly frequency
counts
Ruff (1984) 6 months 60 Undisclosed Evaluation of exploratory Videotaping play with
[3] to suburban behaviour specified objects;
12 months location trained observer, timed
interactive events
Ruff and 9 months 29 Undisclosed Evaluation of young Videotaping play with
Dubinier to suburban children’s ability to specified objects;
(1987) [4] 12 months location manipulate objects and trained observer, timed
their associated behaviour interactive events
KO et al. 1 year to 37 Chicago Children’s touching and Video observation. 2 h
(2006) [21] 5 years mouthing behaviour of video recording
during outdoor play.
Frequency, not amount of
time.
Tulve et al. 10 months 90 Seattle Describe and quantify the Observational study in
(2002) [6] to distribution of soil home environment by
60 months ingestion values. trained observers
5 min to 60 min per day
for 1 day to 6 days,
depending on
scheduling, cooperation
etc.
Xue, J. et al. review review review review Literature review.
(2007) [11]
Reference Age Number of Location of Activity collected Method employed
Range children study collection
Zartarian et 29 months 4 Salinas Left and right hand contact Videotape of waking
al. (1998) to frequency and duration for hours: approximately
Valley, CA
[22] 50 months numerous categories of 1 day of tape per child;
objects computerised
translation software
NOTE SOURCE: Update of Tulve et al. (2002) [6].
2.3 Main results on the duration and frequency of children’s mouthing behaviour in
previous literature
2.3.1 General
There is more literature on the time and frequency of hand-to-mouth behaviour than on object–to-
mouth behaviour. Furthermore, there is great uniformity in the conclusions that instances of indoor
mouthing behaviour are always higher than outdoor mouthing behaviour. Xue et al. (2007) [11]
indicated that the variation between indoor and outdoor behaviour is 60 %.
In their review of previous research, Xue et al. (2007) [11] indicated that average indoor hand-to-mouth
behaviour ranged from 6,7 contacts/hour to 28,0 contacts/hour, with the lowest value corresponding to
the 6 to < 11 year olds and the highest value corresponding to the 3 to < 6 month olds. Average outdoor
hand-to-mouth frequency ranged from 2,9 contacts/hour to 14,5 contacts/hour, with the lowest values
corresponding to the 6 to < 11 year olds and the highest values corresponding to the 6 to < 12 month
olds. However, the authors stated that the analysis highlighted the need for additional hand-to-mouth
data for the < 3 months, 3 to < 6 months, and 3 to 6 year age groups.
The results of the meta-analysis carried out by Xue et al. (2007) [11] and Tulve et al. (2002) [6] indicate
that age and location are important for hand-to-mouth frequency, but type of study and gender are not.
As age increases, both indoor and outdoor hand-to-mouth frequencies decrease. All research concludes
that mouthing behaviour is significantly greater indoors than outdoors. The frequency and duration of
hand-to-mouth, object-to-mouth and food-handling behaviours were all greater indoors than outdoors.
Another widely accepted coincident result is the clear trend that mouthing duration decreases as age
increases. This is consistent with patterns of child development, which show a peak period for
mouthing activity that is positively correlated with teething and negatively correlated with increased
mobility (Juberg el al. 2001 [1], Groot et al. 1998 [2], Xue et al. 2007 [11], Norris and Smith, 2002 [8]).
One more accepted premise is that no significant differences in mouthing times were found between the
sexes, and no significant difference was found for mouthing times at different times of the day (Xue et
al. 2007 [11], Norris and Smith, 2002 [8]).
For this study, results that focused on object-to-mouth contact and the surface area of the objects
mouthed are of primary interest, with a specific focus on toy-to-mouth contact. However, the majority
of results obtained from previous literature featured data on objects in general (sometimes including
toys, but not always).
The results of research indicate that children's mouthing behaviour depends on age and the items
mouthed (e.g. teethers, dummies, toys, etc.). Dummies clearly dominated as the single item most
frequently mouthed by children of all ages (Juberg et al., 2001 [1], Norris and Smith, 2002 [8]).
All studies demonstrated that children mouth many items other than dummies, teethers, and toys
expected to be mouthed (i.e. those products specifically designed for mouthing). A huge variety of items
are mouthed, particularly by children under 1 year, due to teething and using mouthing as a method of
exploring their environment. The variety of objects mouthed indicates that young children have access
to a wide range of non-toy objects, some of which could pose an immediate hazard to them.
Nevertheless, this study will focus exclusively on results concerning toys and mouthing behaviour in
children under 3 years.
2.3.2 Daily time available to mouth not spent sleeping or eating
Around 9 h to 10 h is the average time each day not spent eating or sleeping, as obtained in the Norris
and Smith research (2002) [8]. This is the time during a typical day that a child would have available to
spend mouthing, that is, the time spent neither sleeping nor eating.
Table 2 — Mean, maximum and minimum times available to mouth not spent sleeping or eating
Age group Mean Minimum Maximum
(Hours:Minutes) (Hours:Minutes) (Hours:Minutes)
1 month to 3 months 8:22 3:51 13:30
3 months to 6 months 9:09 6:20 12:48
6 months to 9 months 9:21 7:10 11:50
9 months to 12 months 9:06 6:45 11:23
12 months to 15 months 9:15 7:20 11:05
15 months to 18 months 9:50 6:57 12:42
18 months to 21 months 10:10 8:30 12:15
21 months to 24 months 10:12 6:50 13:39
2 years 10:45 7:35 13:20
3 years 11:10 9:35 13:50
NOTE SOURCE: Norris and Smith, 2002 [8]
In the data obtained there were no significant differences observed in mouthing between the different
times of the day that children were observed. Neither were significant differences in mouthing time
found between the sexes.
However, as can be observed in the following graph, Norris and Smith (2002) [8] found a great
difference between the time available to mouth per day and the duration of children's mouthing
behaviour in contact with objects.
Key
X age group
Y number of hours
1 time available to mouth per day (awake but not eating)
2 estimated children’s mouthing behaviour in contact with objects
a months
b years
NOTE Based on Norris and Smith 2002 [8] data.
Figure 1 — Time available to mouth per day vs. mouthing behaviour in contact with objects
2.3.3 Frequency of mouthing objects
In their study to quantify children's handling and mouthing activities through a videotaping
methodology, Reed et al. (1999) [14] found the mean frequency of contacts per hour: objects-to-mouth
(including toys and other objects), was 16,3 objects, 90th percentile 77,1, and maximum contacts was
86,2 (for a sample of 30 3- to 6-year-olds, and 10 children aged 2 years to 5 years).
Analysis of the data collected by Tulve et al. (2002) [6] suggests that the mouthing data can, and should,
be broken into two subsets based on age: < 24 months and > 24 months. The data further showed that
toys and hands were preferentially mouthed compared with other body parts and household surfaces.
They have obtained a more realistic estimate of a child's mouthing behaviour by using data collected on
multiple observation days. The results reported in this study are focused on children who engaged in
quiet play in an indoor environment. The data presented by Tulve et al. (2002) [6] shows that young
children may mouth specific objects (e.g. toys) up to 48 events/hour.
The research by Black et al. (2004) [18] is presented as a table of results of the frequency of object-to-
mouth events (see Table 3).
Table 3 — Results of the frequency of object-to-mouth events per hour
Age Frequency Time
%
Infant 18,1 (24,4 + 11,6) 3,1 (4,0 + 2,4)
1-year-old 8,4 (9,8 + 6,3) 1,3 (1,6 + 1,2)
2-year-old 5,5 (7,8 + 5,8) 0,9 (1,3 + 1,1)
Preschool 8,4 (10,1 + 12,4) 1,9 (3,0 + 3,9)
NOTE SOURCE: Black et
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