Should football players wear custom fitted mouthguards?
Results from a group randomised controlled trial
C Finch, R Braham, A McIntosh, P McCrory, R Wolfe
See end of article for
Professor C Finch, NSW
Injury Risk Management
University of New South
Wales, Sydney, NSW,
Australia 2052; c.finch@
Accepted 21 March 2005
Injury Prevention 2005;11:242–246. doi: 10.1136/ip.2004.006882
Objective: Head/orofacial (H/O) injuries are common in Australian rules football. Mouthguards are
widely promoted to prevent these injuries, in spite of the lack of formal evidence for their effectiveness.
Design: The Australian football injury prevention project was a cluster randomized controlled trial to
evaluate the effectiveness of mouthguards for preventing H/O injuries in these players.
Setting and subjects: Twenty three teams (301 players) were recruited from the largest community football
league in Australia.
Intervention: Teams were randomly allocated to either the MG: custom made mouthguard or C: control
(usual mouthguard behaviours) study arm.
Main outcome measures: All injuries, participation in training and games, and mouthguard use were
monitored over the 2001 playing season. Injury rates were calculated as the number of injuries per 1000
person hours of playing time. Adjusted incidence rate ratios were obtained from Poisson regression
Results: Players in both study arms wore mouthguards, though it is unlikely that many controls wore custom
made ones. Wearing rates were higher during games than training. The overall rate of H/O injury was
2.7 injuries per 1000 exposure hours. The rate of H/O injury was higher during games than training. The
adjusted H/O injury incidence rate ratio was 0.56 (95% CI 0.32 to 0.97) for MG versus C during games
and training, combined.
Conclusions: There was a significant protective effect of custom made mouthguards, relative to usual
mouthguard use, during games. However, the control players still wore mouthguards throughout the
majority of games and this could have diluted the effect.
urgent attention because they are associated with a risk of
permanent brain or spinal damage; cumulative brain damage
from repeated injury; reduced scholastic performance;
neuropsychological deficits; and cumulative trauma.1This
report also identified the development of specific injury
countermeasures to prevent these injuries as a research
Mouthguards are widely recommended as an essential
piece of protective equipment for football players.1 2A
number of retrospective studies investigating mouthguards
have shown a general trend towards a reduction in the
incidence and severity of orofacial injuries among mouth-
guard users.3–5The scientific evidence for their protection
against head injuries is limited, although this has never been
tested in a prospective study.6Although not compulsory in
Australian rules football, mouthguard use is widespread at
the higher levels of competitive play.7At the community
level, usage is less at approximately 60–70% of players during
games and almost non-existent during training.3 7
Most mouthguards used by players are the over the counter
‘‘boil and bite’’ type and are considered to have limited
effectiveness in injury prevention compared with custom
made mouthguards.2 8Despite the widespread support given
to mouthguards in football, controlled trials of mouthguards
in the football field have not been undertaken to date.2 8
Ethylene vinyl acetate (EVA) custom mouthguards have
been shown in laboratory tests to offer superior protection to
the teeth than a boil and bite design.9However, within
custom EVA mouthguards, variations in thickness, density,
and coverage influence the level of protection provided,9—for
n its 1995 report Football Injuries to the Head and Neck, the
National Health and Medical Research Council of Australia
identified the prevention of these injuries as requiring
example, 5 mm thick EVA offered the greatest protection and
extending the guard to behind the first molar offered further
benefits. Westerman et al observed no improvements in the
impact energy attenuation performance of 4 mm thick EVA
mouthguards with the introduction of gas cells in the foam.10
A finite element study of mouthguard performance found
that mouthguard stiffness is very important to provide load
distribution and protect the teeth, leading to the conclusion
that either sports specific mouthguards are required, or that
composite materials are required that both attenuate energy
and distribute load.11
The aim of this study was to determine the extent to which
custom made mouthguards are effective for the prevention of
head/orofacial (H/O) injuries in Australian rules football
players. It was hypothesized that custom made mouthguards
would reduce the rate of H/O injuries, relative to usual
A group randomized controlled trial (RCT) design was used
because players belong to football teams and interventions
need to be delivered at the team level, whereas the injury
impacts are measured at the player level. Initially, this study
was designed as a four arm factorial trial to also assess the
effectiveness of headgear in these players (headgear, mouth-
guards, headgear+mouthguard, control). However, so few
players wore headgear12that it was not possible to assess its
effectiveness and so the study design was collapsed to a two
Abbreviations: EVA, ethylene vinyl acetate; H/O, head/orofacial; IRR,
incidence rate ratio; PDC, primary data collector; RCT, randomized
arm factorial trial. Table 1 summarizes the two arms of the
study, the allocation of randomization units to study arms,
and player recruitment rates.
Teams of players were randomly allocated to one of two
mouthguard wearing behaviors: MG, custom made mouth-
guards and C, control (usual mouthguard behaviors).
Players assigned to the MG arm were provided with a
trilaminate mouthguard custom fitted by a dental technician
at no cost. They were made from polyvinyl-acetate-poly-
ethylene and chosen because formal materials testing
demonstrated their protective efficacy in laboratory studies
suggesting that they provided the best protection for teeth
compared with other available mouthguards.13The dental
technicians took moulds of each player’s top and bottom
teeth so that the mouthguard could be moulded exactly to fit
their specific dentition.
Players were requested to wear their allocated protective
equipement for all training sessions and competitive games
during the 2001 playing season. For ethical reasons it was not
possible to restrict mouthguard use in control players and
some may have chosen to wear a custom fitted mouthguard
of a different type. Mouthguard use, whether of allocated
equipment or self provided, was monitored for every player
(as described below).
Randomization and recruitment
Teams of players from clubs from the largest district
Australian rules football competition in Australia were
invited to participate. All 40 clubs were invited to participate
and nine did so. Although involved in competitive play, no
player was an elite or high level player.
Randomization to study arms occurred after clubs/teams
agreed to participate in the study. The randomization units
were teams of players from the under 16 years, under
18 years, and open (seniors and reserves) competition levels.
Seniors and reserves teams were randomized together
because players often swap between these teams within a
club during the season. Randomization was stratified by level
of competition to balance age across the study arms.
After team study arm allocation, all players were given
information about the study, the protective equipment they
would be required to wear (if any) and details of the
recruitment and study procedures. Player recruitment was
undertaken on site over two club training sessions during the
pre-season period. Each recruited player was given a plain
language statement and completed an informed consent
form. The study was approved by the Deakin University
Ethics Committee. Data collection procedures were only
completed for players who consented to be part of the study.
Non-responder surveys were undertaken to ascertain why
players and clubs did not volunteer for this study.14 15
Players completed a piloted baseline questionnaire16on their
demographic profile, football playing history, previous foot-
ball injury history, general attitudes towards protective
equipment, self reported usual behaviors in relation to
protective equipment, and risk perceptions. Full details of
this study component have been published elsewhere.17
All field work procedures were standardized. A primary
data collector (PDC) was nominated from each team to
undertake the on site data collection during each game and
training session. All PDCs received formal training in the data
collection procedures and were given a procedures manual
including the data collection forms for recording exposure,
compliance, and injuries, and full details of the coding and
classification schemes. The accuracy of the PDCs’ activities
was assessed by an independent auditing process and found
to be highly reliable.18
The PDCs recorded injured player details for each game
and training session including a description of all injuries
sustained and the injury circumstances. Information about
injury outcomes (that is, time away from sport and amount
of treatment received) was also collected. The injury details
have been published elsewhere.19 20The data were obtained
from the PDCs on a regular basis throughout the playing
season. For each player, the amount of time (in hours) spent
design and numbers of recruited teams and players
The Australian football injury prevention project
No of teams randomized
No of teams participating
No of randomization units*
Division of team
Seniors (firsts or reserves)
Juniors (U16 or U18)
No eligible players
No recruited players
Players response rate
Average exposure per
player per week (minutes)
106 (range 80–120) 105 (range 80–120)
141 (range 60–180) 153 (range 60–180)
*Seniors and reserves were randomized together.
each study arm
Baseline characteristics of players recruited to
VariableC (n=111) MG (n=190)
Division, n (%)
Team, n (%)
Age (mean (SD))
BMI (mean (SD))
Previous head/orofacial or neck injury, n (%)
Wore mouthguard in previous season, n (%)
Pre-season mouthguard risk taking
behavior score (mean (SD))
Perception of head injury risk
Perception of mouth/dental injury risk
Should football players wear custom fitted mouthguards?
playing football (both competition and training) over each
week of the trial was also recorded. The PDCs also reliably
recorded whether or not players actually used their allocated
protective equipement each week.18
Head/orofacial injuries were defined as any injury, ir-
respective of severity, to the forehead, scalp, ears, skull, brain,
face, jaw, or dentition.
Analyses were performed with STATA21and performed on an
intention to treat basis, with the control arm as the reference
in the calculation of rate ratios. Baseline player characteristics
were examined for equivalence in injury risk at baseline
across the study arms.
Injury rates were calculated as the number of injuries
divided by time exposed (at training or games) and expressed
per 1000 person hours of playing time. Incidence rate ratios
(IRR) were obtained from Poisson regression models, with a
player’s number of injuries in a game or training session as
the outcome variable and exposure time as a log offset term,
together with risk factors in the linear predictor part of the
model. The factors considered for adjustment in these models
are shown in table 2. Incidence rate ratios for time-varying
risk factors were able to be calculated because the data were
split into individual units of exposure (that is, training
sessions and games for each player in each round). Robust
standard errors were calculated using the information
sandwich formula to account for clustering of players in
the original units of randomization.21
Table 1 describes the composition of the study sample and
the randomization units. After randomization, four teams
dropped out of the study for reasons unrelated to the study
arm allocation: not fielding a team for the 2001 playing
season; not being able to complete the required study
procedures of injury surveillance and exposure recording; or
unable to arrange a time for player recruitment.
There was some imbalance of teams between the two study
arms—for example, a greater proportion of the control teams
were seniors compared with the MG group; however the
balance of players between study arms was reasonable
(table 2). The player recruitment rate was higher in the MG
arm and hence there was more total exposure in this arm;
however average game time and training exposure per player
per week was similar in the two arms. Apart from the division
of play, there were no major differences between study arms.
Irrespective of the study arm, the vast majority of players
wore mouthguards during games, indicating that most
control players still chose to wear mouthguards. In contrast,
few players wore mouthguards during every training session.
The H/O injury rate was 2.7 injuries per 1000 hours of
participation (95% CI 1.6 to 4.5). The most common H/O
injury was a facial laceration (38% of all H/O injuries) and
these were 1.4 times more common in control players than
MG players. Concussions (19% of all H/O injuries) were
distributed roughly equally across study arms. The only
player from the MG arm to receive a dental injury was not
wearing their mouthguard at the time of injury.
The overall injury rate was 12.8 (95% CI 7.1 to 23.1)
injuries per 1000 participation hours. There was a higher rate
of H/O injury in the control arm than in the MG arm, when
training and game exposures were combined: 4.4 (95% CI 2.2
to 8.9) injuries/1000 exposure hours versus 1.8 (95% CI 1.1 to
2.9) injuries/1000 exposure hours, respectively. The H/O
injury rate was significantly higher during games than
training sessions both overall (5.8 (95% CI 3.5 to 9.6) v 0.4
(95% CI 0.1 to 1.4), respectively) and in both study arms—
controls (8.9 (95% CI 4.3 to 18.6) v 0.7 (95% CI 0.1 to 3.1),
respectively); MG arm (4.1 (95% CI 2.5 to 6.7) v 0.2 (95% CI
0.0 to 1.2), respectively).
Figure 1 shows the study arm H/O injury rate comparisons,
after adjusting for division of play and age group—two
factors showing an association with injury and imbalance
between study arms (table 2). There was some evidence of a
protective effect of mouthguards during games and training
combined (unadjusted IRR=0.41; adjusted IRR=0.56; 95%
CI 0.32 to 0.97: p=0.04). When only game exposure was
considered, the MG arm had a reduced rate of H/O injuries
relative tocontrols (unadjusted
IRR=0.60; 95% CI 0.35 to 1.02; p=0.06).
Given the relatively high level of participation in Australian
rules football by Australian males and the predominance of
associated injury presentations at medical services, this sport
is a high priority for injury prevention research.8Although
preventive measures have been adopted to varying degrees,
the current lack of an evidence base about their effectiveness
limits the safety advice that can be given to football
participants, their parents, coaches, and sports administra-
tors.8This study is the first RCT of the effectiveness of any
injury prevention measure in community Australian rules
football and one of only a very few in any level of football
Although the protective effect of mouthguards against
head injury remains theoretical22with only anecdotal23or
limited clinical evidence24 25to suggest a beneficial effect, it
was nevertheless important to test this premise of mouth-
guard efficacy in a controlled study. It can be intuitively
appreciated that mouthguards are likely to offer a more
protective effect in relation to orofacial injuries. However, at
this level of football such injuries are uncommon and a
controlled study would have needed to be significantly larger
in order to have adequate power to detect a benefit if present.
Given the budgetary and logistic constraints of this study, it
was not considered feasible to test these hypotheses
Intervention arm and exposure adjustment
Rate ratio (log10 scale)
MG (games +
injury rates in the mouthguard arm, relative to controls (p=0.06 for
mouthguards v controls during games and p=0.04 for mouthguards v
controls during games and training combined).
Incidence rate ratios comparing adjusted head/orofacial
244Finch, Braham, McIntosh, et al
Our study has demonstrated that custom fitted mouth-
guards provide significant protection against H/O injuries,
relative to usual mouthguard behaviors, during combined
games and training exposures. Wisniewski et al found no
difference in the rate of concussion between players wearing
boil and bite mouthguards and custom made mouthguards in
National Collegiate American Football.26Mouthguards only
provide impact energy attenuation during impacts to the
mouth, and therefore have a very limited function in
Comparing the player recruitment rate in the two study
arms suggests that the provision of custom made mouth-
guards was a significant incentive for players to participate.
However, although players adopted mouthguards for the
game situation, fewer did so during training, even though
there is still a risk of H/O injury. Even with optimally
designed protective equipement, unless players choose to use
it, it will not be an effective form of protection. There is no
necessity for players to wear mouthguards unless engaged in
training that involves potential contact. But wearing protec-
tive equipment during training is important as it provides an
opportunity for players to develop an awareness of its
limitations and usability issues—for example, comfort and
The magnitude of the protective effect demonstrated for
the protective equipement tested in this trial across training
and game sessions is most likely to be related to (a) the fact
that players did not wear their allocated protective equipment
all of the time and (b) the study being underpowered. Player
recruitment was affected by the ethical and practical
requirement of informing players of what they would be
required to do before they signed up for this study.
Another problem with the study was the nature of the
control arm. For ethical reasons, we could not prohibit
control players from wearing their usual mouthguards, if any.
This has led to a likely dilution of the differences between the
two study arms, as the control arm was not a true control.
Thus this study did not test mouthguard wearers against
non-mouthguard wearers. Rather it could only compare
players who wore the supplied mouthguard to those who
wore their own mouthguards. However, baseline assessment
and previous published research indicated that players
generally do not choose to use custom fitted mouthguards.7
This study has a number of significant strengths. Firstly, it
adopted an RCT methodology, which is regarded as providing
the highest level of evidence for the effectiveness of an
intervention. A group randomized design was used because it
replicated the setting of application of the interventions in
the real world. Thus the study provides a model for future
sports injury research. Secondly, the intervention had
previously undergone rigorous lab based testing and its
impact properties were well known. Thirdly, the study
adopted a rigorous and highly reliable data collection
Block allocation of junior (U16 and U18) and senior
(seniors and reserves) teams to study arms was used to
balance for most factors. However, this balance did not
extend to division of play. Conventionally, better skilled
players participate in a higher level of competition. Division
IV is a lower level competition than Division III or II. As a
higher proportion of control teams were Division IV players,
we adjusted for this factor as well as age group in our
comparisons. Some of the injury rate difference is explained
by these factors, although a protective effect of borderline
statistical significance remained.
This first randomized controlled trial in community level
Australian football players has shown that they do not always
choose to wear protective equipment. However, custom fitted
mouthguards seem to be protective against H/O injuries,
relative to usual mouthguard behaviors. It is therefore
recommended that Australian football players should wear
custom fitted mouthguards, rather than the boil and bite type
or no mouthguards.
C Finch, NSW Injury Risk Management Research Centre, University of
New South Wales, Sydney, NSW, Australia
R Braham, R Wolfe, Department of Epidemiology and Preventive
Medicine, Monash University, Victoria, Australia
A McIntosh, School of Safety Science, University of New South Wales,
Sydney, NSW, Australia
P McCrory, Centre for Health, Exercise and Sports Medicine & the Brain
Research Institute, University of Melbourne, Melbourne, Australia
R Braham is now at the School of Human Movement and Exercise
Science, University of Western Australia
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N This is the first randomized controlled trail of the
effectiveness of protective equipment in community
level Australian football, and one of a few worldwide
in any sport.
N Players who were allocated to the custom fitted
mouthguard study arm had a significantly lower rate
of head and orofacial injuries than all other players.
N There are significant challenges in conducting rando-
mized controlled trials in sporting populations.
Should football players wear custom fitted mouthguards?
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associated with type of mouthguard used in college football. Dent Traumatol
State ‘‘protecting’’ traffic information
to protect against lawsuits claiming the state moved too slowly to correct known traffic
hazards. Transportation officials say the threat of multi-million dollar settlements justifies
withholding the information, and they would rather use the money for safety improvement
projects. "I’d like to make the state a model for information-sharing like other places, where
they don’t have to worry about having that information thrown back into their faces by the
attorneys," said Alvin Takeshita, head of the state DoT’s Traffic Branch. Under state and
federal law, state traffic data are inadmissible in civil cases, but Takeshita said attorneys get
around the law by introducing county police reports with the same information. Other states
have opted to release the data after redacting personal information about those involved in
crashes. Some states have tried to make the data as accessible as possible by posting the
information on public websites, so that drivers and pedestrians can see which locations have
the most crashes. Critics of the state’s policy say the public needs to see the state data to
determine whether state and county transportation officials are making good decisions
about which crash locations to improve or repair, and to make informed decisions about
where and when to travel.
Reported in CDC Public Health Law News. Contributed by Ian Scott.
awaii’s Transportation Department spends millions of dollars each year studying
traffic safety, but the agency does not share the findings with the public or other
government agencies. Hawaii is one of a few US states that withhold the information
The Age (Melbourne), May 2005. Contributed by Ian Scott.
Russian woman’s fingers were badly bitten when she tried to clean her son’s fish
tank, unaware the fish were piranhas. She told doctors she thought they were well-
246 Finch, Braham, McIntosh, et al