The American Academy of Orofacial Paindefines bruxism as a diurnal or nocturnal

parafunctional activity including clenching, bracing,gnashing, and grinding of the teeth1.

The prevalence of oral parafunction in the generalpopulation is very variable, different studies reportdifferent results also according to the method used toassess the pathology. Generally, awareness of bruxismranges from 6% to 27.2%2-6, but EMG nocturnalrecordings during sleep show masticatory musclesactivity in 100% of the subjects2. The most commonway of evaluating the presence of tooth grinding indental patients is to look at dental wear, and data showthat using such analysis we can find positive results in

about 50% of them2.To date, what causes bruxism is not clear. Although

many theories have been proposed none of them hasproved a cause-and-effect relationship with the onsetof oral parafunctions.

Occlusion has been anecdotally correlated to toothgrinding, yet clinical studies give controversialresults7-13. Interesting is the role of stress indetermining increase of bruxism, in fact some studiesshow a clear temporal association between the twovariables7,14, but others fail to confirm such data15,16.

A different issue is the presence of neurologicaldisorders that can be associated with involuntarymuscular movements involving the oral structures,such as extrapyramidal disorders17-19, or chronic use ofmedications that can elicit bruxism as side effect:SSRIs20-24, amphetamines25, fenfluramine25,26,L-dopa25,27, phenothiazine25, and other neuroleptics28.

Damage to the oral structures caused by oral

TMD and Orofacial Pain

Journal of the Lebanese Dental Association

Bruxism Prevalence in a Selective Lebanese Population

31

Statement of the problem: In recent years, many Lebanese dentists reported an increase in night-time parafunctional activity

of their patients.

Purpose of the study: To investigate night bruxism awareness in a selective Lebanese population.

Materials and Methods: 868 visitors of a shopping mall in the city of Beirut (Lebanon) were interviewed about their habit

of clenching and grinding their teeth at night, and about their age and gender. Gender distribution was as follows: 530

females and 338 males, mean age was 34.9 (±11.6 SD) and 37.8 (±14.6 SD) respectively.

Results: Overall prevalence of bruxism was 35.8% for males and 32.6% for females with no statistically significant

difference between the two groups. Bruxism was found to increase with age for both genders. Bruxism awareness per

age and gender was as follows: <26 years (F: 24.1%; M: 19.4%), 26-35 years (F: 26.1%; M: 27.2%), 36-45 years (F:

41.1%; M: 41.6%), 46-55 years (F: 41.5%; M: 50%) and >55 years (F: 63.6%; M: 53.5%).

Conclusion: Night bruxism prevalence in this Lebanese group seems to be higher than in reported western studies and a

deeper socio-economical investigation is needed. Future larger scale studies might be needed to confirm if bruxism

awareness increases with age.

* Private Practice, Beirut, Lebanon.

† Private Practice, Cagliani, Italy.

§ PhD Candidate, Boston University, Goldman School of

Dental Medecin, Boston, USA

Youssef S. Abou-Atme, DDS, MS* Marcello Melis, DMD, RPharm† Khalid H. Zawawi, BDS.§

parafunctions includes teeth (attrition, fractures)29-31,periodontium (tooth mobility, abfractions)30,temporomandibular joints (noises, pain, boneremodeling)32,33 and masticatory muscles (pain,fatigue, stiffness)32-36, that can be variably affected37.

Since etiology of bruxism is unknown, treatment isdesigned to prevent its effects on the masticatorysystem. Use of occlusal appliances38-43 limits thedamage to the teeth, periodontium,temporomandibular joints and the masticatorymuscles; in addition to that, other procedures can beeffective reducing overall parafunctions. Mostreported are stress management44, biofeedbackmodalities42,44,45 and eventually medications44,46,47.

PURPOSE OF THE STUDYThe purpose of this study was to detect the

prevalence of night bruxism awareness in shopping

mall visitors in the Lebanese capital Beirut, exploring

the relationship between bruxism and two factors: age

and gender.

MATERIALS AND METHODSDuring the summer of 2001, a total of 868 adult

subjects among the visitors of a shopping mall in thecity of Beirut (population 1.1 million) the capital ofLebanon (population 4.3 million mid 2001)48 wereinterviewed regarding their age and gender, as well asany habit of teeth clenching or grinding at night.Questions regarding oral parafunctions were thefollowing:

1- Do you clench your teeth at night?2- Do you wake up in the morning with your jaws

braced together?3- Were you told that you make noises with your

teeth while asleep?

No effort was made to verify the data and to

distinguish symptomatic from asymptomatic people.

Two investigators in a shopping mall area, but without

standardized randomization, recruited the subjects.

Answering positively to one question was interpreted

as presence of nocturnal oral parafunctions. The

response rate was not recorded by the investigators.

STATISTICAL ANALYSISSubjects were divided by gender and grouped in

four age categories for each gender. Age categories are

similar to those used previously5; i.e., less than 26

years, 26-35, 36-45, 46-55 and more than 55 years. Chi

square (χ2) test was performed to study the

relationship between gender and bruxism, and age and

bruxism. The level of significance was accepted for

p<0.01.

RESULTSA total of 868 subjects participated in the study,

530 females and 338 males, mean age was 34.9 (±11.6

SD) and 37.8 (±14.6 SD) respectively. 294 (33.9%)

reported being aware of night bruxism.

No significant association was found between

gender and reported bruxism, χ2df=1

= 0.4, p>0.1,

(35,8% for males and 32.6% for females). On the other

hand, there was a significant association between age

groups and bruxism, χ2df=4

= 45.8, p<0.0001.

Table 1 shows the distribution of Bruxism by age

and gender.

Table 1. Bruxism by age and gender

Age Range Gender Bruxism No Bruxism Total

< 26 years Females 28 (24.1%) 88 (75.9%) 116

Males 14 (19.4%) 58 (80.6%) 72

26-35 years Females 53 (26.1%) 150 (73.9%) 203

Males 25 (27.2%) 67 (72.8%) 92

36-45 years Females 51 (41.1%) 73 (58.9%) 124

Males 32 (41.6%) 45 (58.4%) 77

46-55 years Females 27 (41.5%) 38 (58.5%) 65

Males 27 (50.0%) 27 (50.0%) 54

> 55 years Females 14 (63.6%) 8 (36.4%) 22

Males 23 (53.5%) 20 (46.5%) 43

Total 294 574 868

Abou-Atmé YS, Melis M, Zawawi KH

Volume 41 - Nº 2 - 200432

DISCUSSIONIn the population we examined 294 subjects

reported nocturnal bruxism, which is 33.9% of the

individuals. This result is higher than the percentages

that are usually reported in the literature, even though

the studies show very different values according

probably to different populations examined and

different ways to evaluate bruxism awareness.

Prevalence ranges from 6 to 27.2%2-6. The results are

even more evident considering the fact that our

questions were asked to detect only nocturnal

parafunction, which usually occurs without the

subjects being aware of it. We cannot exclude and we

can even expect that adding to our results overall

bruxism occurring day and night, or bruxism

occurring during the day only, the percentage of

people that reported parafunction would increase

further.

The reason for this high percentage of individuals

affected by night bruxism is unknown, but one might

suspect the effect of the worsening socio-economical

crisis in Lebanon at the time of the survey. We should

say that our study was performed without any attempt

to reach a population that was a representative sample

of the entire Lebanese population: subjects were

interviewed casually and we cannot exclude bias

coming from involuntary selection of the individuals.

The shopping mall itself where the subjects were

recruited is geographically situated in the middle of

Beirut, and is routinely visited by middle and high

social and economical classes of shoppers. The actual

study may be used as a pilot for future nation-wide

bruxism surveys in Lebanon.

Referring to the theories on the etiology of

bruxism10 we should say that we do not have elements

to assess the factors eventually playing a role in the

pathogenesis of bruxism in the population surveyed.

We did not gain any information regarding occlusion,

neurological diseases and medications, and

psychological factors of the subjects we examined,

because finding the cause of parafunction was not the

purpose of the study. Yet, these conditions might have

altered our results.

Based on the outcome of this study, gender seems

not to make a difference in the overall awareness of

nocturnal bruxism, and the same results were found

by Glaros4 in a study where overall parafunctions

where equal in men and women. On the other hand,

age was found to correlate with bruxism: whether

genders were combined or separate, bruxism

awareness tended to increase with age (Table 1). This

is the first time such age related parafunctional

awareness is reported. It might be due to life

experience, including an increase of responsibility

with age, exposure to stressful events and pain

experiences, along with increase of general health

awareness because of great availability of new means

of divulgation such as television, radio and internet.

Life experience would also mean a great contribution

from psychological factors in the etiopathogenesis of

bruxism, but that is still controversial34,35,40,41.

CONCLUSIONSThe present study seems to show a higher

prevalence of nocturnal bruxism in the Lebanese

population compared to other previous studies in

western populations. Awareness of nocturnal

parafunction was found to increase with age for both

genders. This new finding should be investigated in

future studies. Larger surveys are needed to find out

the relationship between the Lebanese socio-economic

situation and bruxism.

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Dr. Youssef Abou-AtmeMedawar St, Akar Bldg, Badaro, Beirut, Lebanon 2058-7017Email: youssefaa@yahoo.comPhone: +961-3-853556 - +961-1-612761Phone/Fax: +961-1-612762E-Fax: +1-509-351-3240

Journal of the Lebanese Dental Association 35

Abou-Atmé YS, Melis M, Zawawi KH