ARTÍCULOS ORIGINALES
Association between signs and symptoms of temporomandibular disorders and pregnancy (case control study)
Verónica A. Mayoral1, Irene A. Espinosa1, Álvaro J. Montiel2
1 School of Stomatology, Meritorious Autonomous University of Puebla, Mexico
2 General Regional Hospital 36 of Mexico's Social Security Institute (IMSS), Puebla, Mexico
CORRESPONDENCE Mayoral Garcia Veronica Anuette 26 poniente 3511 Fraccionamiento Valle Dorado C.P. 72070 Puebla, Pue. Mexico verona_2001@hotmail.com
ABSTRACT
Temporomandibular disorders (TMD) are a combination of multifactoral etiological muscular-skeletal symptoms. Prevalence is greater in women, where sexual hormones are important in pathogenisis, and its behavior at different stages of the reproductive life of women has never been fully documented. The general objective was to determine the association between signs and symptoms of temporomandibular disorders and pregnancy. A case-control study was conducted on 66 pregnant patients who met with a medical specialist and 66 non-pregnant women paired by age, who visited the General Regional Hospital 36 of Mexico's Social Security Institute (IMSS). These patients were examined for the Temporomandibular (TMD) research project to establish the prevalence of TMD in both groups. Descriptive variables were calculated through him SPSS 17 program and the association between groups with Xi Square and Ratio Possibilities (OR), The average age was 28.23 } 5.9 years in both groups, with median gestation 32.97 weeks. Most of the participants had a domestic partner. The prevalence of TDM in the non-pregnant group was 45.5% and only 15.2% in the pregnant group (X2=14.34, p<.000). We calculated the ratio of possibilities (RP) pregnant/non-pregnant with a value of 41 with confidence intervals from 23 to 72. In conclusion, pregnancy protects women from TDM signs and symptoms. Pregnant women have a considerably lower prevalence of these disorders.
Key words: Temporomandibular Joint Disorders; Pregnancy.
Asociación entre los signos y síntomas de los trastornos temporomandibulares y el embarazo(estudio de casos y controles)
RESUMEN
Los Trastornos Temporomandibulares (TTM) se refieren a una coleccion de condiciones medicas y dentales que afectan a la Articulacion Temporomandibular (ATM), y/o musculos masticatorios, asi como estructuras vecinas. Otros autores definen los TTM como un conjunto de sintomas musculo-esqueleticos de etiologia multifactorial. La prevalencia es mayor en mujeres, donde las hormonas sexuales son importantes en la patogenesis y su comportamiento en las diferentes etapas de la vida reproductiva de las mujeres no ha sido completamente documentado. El objetivo general fue determinar la asociacion entre los signos y sintomas de trastornos temporomandibulares y el embarazo. Se realizo un estudio de casos y controles con 66 pacientes embarazadas que acudieron con medico especialista y 66 no embarazadas pareadas por edad que acudieron a consulta al HGR 36 del IMSS. Fueron exploradas por medio de los Criterios de Diagnostico para la Investigacion de los Trastornos Temporomandibulares (CDI/TTM) para establecer la prevalencia de TTM en ambos grupos. Se calculo estadistica descriptiva de las variables a traves del programa SPSS v.17 y la asociacion entre grupos con Chi cuadrada y Razon de posibilidades (OR). La edad promedio fue de 28.23 } 5.9 anos en ambos grupos, con una media de semanas de gestacion de 32.97. La mayoria de las participantes contaron con una pareja. La prevalencia de TTM en el grupo de las no embarazadas fue del 45.5% y de solo el 15.2%, en las mujeres embarazadas (X2=14.34, p<.000). Se calculo la razon de posibilidades (OR) embarazadas/no embarazadas con valor de .41 con intervalos de confianza de .23 a .72. En conclusion, el embarazo es un factor protector para presentar signos y sintomas de TTM, las mujeres embarazadas presentan una prevalencia considerablemente mas baja de dicho padecimiento.
Palabras Clave: Trastornos Temporomandibulares; Embarazo.
INTRODUCTION
Temporomandibular disorders (TMD) refer to a collection
of medical and dental conditions affecting the
Temporomandibular Joint (TMJ) and/or the muscles
of mastication, as well as contiguous tissue components1.
Other authors have described TMD as a constellation
of related pathological changes that produce
muscular-skeletal symptoms. These can be detected
by pain associated with chewing, limited jaw movement
and painful temporomandibular jaw action 2.
Prevalence of TMD has been reported as almost
80% and a proportion of 3 females to each male 3.
Kuttitla establishes that women suffer more TMD
that men at a rate of 3:1, without determining the
age intervals 4. According to a study conducted by
Slade in a Canadian population, women showed a
greater prevalence of TMD signs and symptoms
than men, mainly with 11.1% of women expressing
muscular pain and only 4% of men expressing discomfort,
with significant statistical differences
(p<0.0001) 5. In relation to temporomandibular disorders
in women, according to Janal, a prevalence
of 10.5% in women in New York has been documented,
almost all of whom (10.1%) were young
women of low-income socioeconomic status 6.
The authors coincide in that Temporomandibular
Disorders are of multifactorial origin, where risk
factors can be genetic, physiological, traumatic or
oral habits 7, among others 8-10, with a greater prevalence
in females, in whom hormone variations
could be a determining factor because hormones
evidently play a role in etiology. 11-14. Hormonal
changes include menarche, the menstrual cycle and
menopause, among others; however the longestlasting
hormonal change is pregnancy 15.
Pregnancy is defined as the "physiological state of
women initiated with fertilization and ending in
labor and birth" 16, gestation is a physiological state
in which the woman undergoes important static
organic, endocrinometabolic and cardiovascular
changes.
The impact of hormones on pain perception has
been documented by several authors. Francis Chacon
talked about the difference in perception of pain
between men and women and found that women
have greater risk of neuropathic pain and greater
prevalence of muscular-skeletal pain 2. Michelle P.
Warren reported that the severity of pain is also
related to the ages of the women. The onset of
painful syndromes tends to occur after puberty and
peaks during the reproductive years, predominating
in women between the ages of 20 and 40 years 11.
The tissues of the Temporomandibular Joint (TMJ)
contain numerous cells with estrogen receptors,
particularly the condyle, the disc, and the capsule
joint and to a lesser extent, the muscles of mastication
16. These structures can be considered a target
for sexual steriods, particularly estrogen,
which acts on the bones with an antiresorption
caused by the inhabition of osteoclastic activity,
and there is great influence on the cartilage Furthermore,
estrogen and progesterone can influence
the content and characteristics of collagen fibers
by increasing the amount of collagen type III but
decreasing collagen type I; the expression of the
estrogen receptors and the effect of said estrogen
on ligament components is that the presence of
collagen type III was related to the decrease in the
perception of pain17.
Another possible hormonal factor is relaxin, which
is a female hormone produced by the corpus luteum.
It appears in the blood during the days prior to the
menstrual cycle and sporadically during the full term
of pregnancy, so that during delivery there is muscle
relaxation. It also modulates muscle activity in
female reproductive organs. The increase in combined
systemic relaxation in pregnant women has
been linked to high levels of relaxine 11. LeResche,
upon studying the effects of oral contraceptives on
TDM pain, found that is much higher in women at
times of high estrogen concentration 18.
Suarez showed that adolescents at the beginning of
the menstrual cycle have a greater number of TMD
signs and symptoms than those in whom where
menarche is not present 14, Muscular-skeletal orofacial
and symptoms related to TDM appear to
improve during the period of pregnancy, mainly in
the last days of the term, which was correlated with
high levels of estrogen 15.
The association between pregnancy and TMD
symptomology is still uncertain. Hormonal changes
appear to influence the pain threshold in women and
the discomfort of those suffering TMD is characterized
at the muscular-skeletal level, and could be
influenced by hormonal changes provoked during
pregnancy, which is why the aim of this study was
to identify the association between TDM and pregnancy
in women who sought medical treatment at
the IMSS in Puebla.
MATERIAL AND METHODS
Under the observational analytical design, we previously
calculated the size of our sample, which
included 66 pregnant patients seeking care for their
pregnancies from medical specialists and 66 nonpregnant
patients seeking medical care, both groups
at the IMSS General Regional Hospital No. 36 in
the city of Puebla. The selection criteria for the
cases were pregnant women of any age and nonpregnant
women that were paired with the case groups. All the women participating signed consent
forms. Exclusion criteria for both groups were
women suffering any systemic illness involving the
muscular-skeletal system and/or those with any
type of disability.
To diagnose TMD we used the Research Diagnostic
Criteria for Temporomandibular Disorders (RDC/
TMD), previously standardized by researcher
(Kappa .78). We began with the background questionnaire
and later with the clinical evaluation conducted
by the same researcher in accordance with
the RDC/TDM. All patients were under the same
environmental conditions, in the prenatal area as
well as the hospital visitor area.
We collected the information and created a database
with the SPSS version 17 statistics program in order
to calculate mean, descriptive, median, percentages,
standard deviation statistics and for the association
between groups we calculated with the Xi squared
statistics test and ratio possibility (OR). The difference
was significant at the 5% level.
RESULTS
From 132 patients, we obtained a median age of 28 years in both groups. The average weeks of gestation in the Pregnant Women were 32.97. Regarding couple status, 77.3% in the case group (pregnant) and 60.6% in the control group (non-pregnant) had a stable partner. In general, the demographics in both groups were similar (Table 1).
Table 1: Socio-demographic characteristics by group.
Information related to TMD signs and symptoms according to the Health Patient Questionnaire show joint click predominately in the group of non-pregnant women, diurnal bruxism was the only sign reported in a majority of pregnant women, while ear buzzing was noted to exactly the same extent in both groups. Most variables did not show statistical differences between groups (Table 2).
Table 2: Signs and symptoms according to Health Patient Questionnaire (RDC/TMD) by group.
In the clinical examination, we observed that there were more painful extraoral muscles, intraoral muscles and joint areas in non-pregnant women, with statistical significance in almost all the variables registered. Only average mouth opening capacity was the same between the groups (Table 3).
Table 3: Signs and symptoms according to clinical examination (RDC/TMD) by group.
** T test
The prevalence of temporomandibular disorders in pregnant women was three times less than in nonpregnant women (Figs. 1-2).
Fig. 1: Prevalence of Temporomandibular Disorders (RDC/TMD)
in pregnant women.
Fig. 2: Prevalence of Temporomandibular Disorders (RDC/TMD)
in non-pregnant women.
Finally we calculated the Odds ratio (OR) of the temporomandibular disorders and pregnancy, and found OR = 0.411 (CI 95% 0.234-0.720) with p<0.000. These results mean that pregnancy protects women from developing signs and symptoms of TMD.
DISCUSSION
The results of this study show that non-pregnant
women have 30.3% more TMD that pregnant
women, in agreement with a study conducted by
Landi14, 17 where epidemiological data suggest that
the symptomology begins after puberty and is lower
in postmenopausal women than in fertile women.
The lower prevalence of temporomandibular disorder
signs and symptoms in pregnant women can be
explained by virtue of pain modulation due to estrogen
as well as migraines, due to the temporomandibular
illness developing during the menstrual
cycle, disappearing with pregnancy and reappearing
after delivery, similarly to the abrupt withdrawal
of exogenous estrogens2.
During pregnancy the pain threshold becomes higher,
explaining why pregnant women have fewer
intraoral, extraoral muscular zones and joint pain
than non-pregnant women.
According to the study conducted by Perez13 on climacteric
women, the prevalence of temporomandibular
disorders is lower in the clinical examination,
probably because the hormones diminish, while in the
present study, during pregnancy the level of hormones
is higher and the clinical examination is lower compared
to non-pregnant women.
Pregnancy produces drastic changes in estrogen and
progesterone and the most significant changes in both
hormones occur during the second quarter, because
their levels increase abruptly around the 12th week of
pregnancy. Higher levels of other forms of estrogen
(estradiol) are also found during the second and third
quarter of pregnancy. All pain, including muscularskeletal
pain in the temporomandibular region, diminishes
at the beginning of the second quarter of
pregnancy and remains low at nine months13. This
was corroborated after an average gestation period of
33 weeks, or after the second quarter of pregnancy.
CONCLUSION
Pregnancy is a protective factor against signs and symptoms of temporomandibular disorders, pregnant women have a considerably lower prevalence of these disorders.
ACKNOWLEDGMENTS
The authors wish to acknowledge the support from Irene Espinosa de Santillana and directors of the General Regional Hospital.
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