Temporomandibular disorders and parafunctional oral habits : An anamnestic study

Results: According to the results from the non parametric statistical analysis, the frequency for the following signs and symptoms was significant: Fatigue and muscle pain, joint sounds, tinnitus, ear fullness, headache, chewing impairment and difficulty to yawn (p<0.01) and otalgia (p<0.05). As to the parafunctional oral habits, there was a significant presence of teeth clenching during the day and night (p<0.01) and teeth grinding at night (p<0.05). The variable correlation analysis showed that there was a positive correlation between symptom frequency and severity; age was correlated with the presence of otalgia, cervical pain and teeth sensitivity, besides being correlated with muscle and joint pain severity. Habit frequency was negatively correlated with age. TMD duration was also positively correlated with the symptoms of tinnitus, ear fullness, muscle and joint pain.


IntROduCtIOn
Temporomandibular disorders (TMD) have been recognized as a common condition of orofacial pain and its clinical manifestation includes a set of signs and symptoms.Among them, pain almost always takes a prominent role, which can impair the functioning of the stomatognathic system and the quality of life. 7,21,36TMD diagnosis is mainly clinical and maybe supplemented by images. 43But often what drives the patient to seek treatment is the sign and symptom perception.
Pain in the masticatory muscles and temporomandibular joint (TMJ), difficulty in jaw movement, joint sounds, difficulties related to stomatognathic functions and otologic symptoms are commonly reported by affected subjects. 7,26t is believed that habits can act as an important etiologic factor of TMD, as they lead to a traumatic dental occlusion that may affect the teeth and the masticatory muscles and temporomandibular joints, causing the disruption of the functional balance stomatognathic system, or worsening the already installed TMD. 16,19,30,31,32Thus, some studies have reported that the amount, frequency, intensity and duration of habits can determine the severity of signs and symptoms of TMD, as they relate to fatigue and muscle pain, in addition to joint compression. 13,15,30nychophagy, gum chewing, biting or clenching objects between the teeth, constantly biting cheeks and lips, resting the jaws on the hands, clenching and/or bruxism, among other habits, are commonly reported by TMD patients. 16,31,32tudies have shown that anamnestic investigation is valid for the identification of TMD 14 and it may also give positive correlations with clinical findings. 14,28Previously, our team standardized the patient records about signs and symptoms of TMD, which allowed the definition of the frequency and severity of the condition, as well as verification of the treatment effects. 13he objective of this study was to determine the frequency and severity of TMD signs and symptoms and the frequency of deleterious oral habits present in a sample by means of a questionnaire to assess self-perception of symptoms, and to examine possible correlations between the variables: Age of the subjects, severity of symptoms, frequency of signs and symptoms, number of habits, duration of TMD.

MateRIal and MetHOdS
The project was approved by the Ethics Committee of the School of Dentistry of Ribeirão Preto, University of São Paulo (process number 2001.1.266.58.5).All subjects were informed about the objectives of the study and signed an informed consent.
One hundred female subjects, with ages ranging from 11 to 74 years (mean 33.49years) participated in this study.They were choose because they were the majority seeking for treatment on the waiting list.

Procedures
The patients were called for treatment of TMD, in a waiting list of the university.
The inclusion criterion was to present classification of muscular and/or articular TMD according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD), 9 applied by a trained examiner.Therefore, the subjects should have TMD signs and symptoms and the presence of pain in the masticatory muscles and/or the temporomandibular joint, limitation or deviation of mandibular movements, TMJ sounds and static and/or unusual dynamic occlusal relationship. 7xclusion criteria were patients with central or peripheral neurological disorders, or who had suffered trauma or tumors in the head and neck.
The subjects were examined while seated in a dental chair with adequate lighting.To check the conditions, morphofunctional evaluation was made of the static and dynamic occlusion.To identify the regions of pain, it was performed palpation of the masseter, temporal, suprahyoid, medial and lateral pterygoid, the insertion of the temporalis muscles (intraoral) and TMJs.The region of TMJ was also palpated during mandibular motion for the identification of joint noises, which were confirmed by auscultation.Clinical examination was carried out based on the criteria required by the protocol RDC/TMD. 9o obtain data on the perception of the subjects for signs and symptoms of TMD, it was used the "Protocol for Multidisciplinary Centers for the Determination of Signs and Symptoms of TMD (ProDTMMulti), which contains 2 parts.Patients answered questions of the first part of the protocol, which admitted only affirmative or negative answers about the signs and symptoms and deleterious oral habits.In the second part, they were asked to express the severity of signs or symptoms questioned according to the situation, that is, at waking up, chewing, speaking and at rest, using a 11-point numerical scale, with the help of a printed graduated scale: Zero was considered complete absence of symptoms or signs, and 10 the greatest severity possible.The severity scale was composed by the sum of the scores assigned to each sign and/ or symptoms in the four questioned situations.The procedures were performed individually and patients' responses to each item were marked by the same examiner in the protocol.
To obtain data on deleterious oral habits, subjects were asked about the presence of the following behaviors: Clenching during day and/or nighttime, grinding teeth during day and/or nighttime, chewing gum, biting objects and nails, and some other habit that had not been questioned.The subjects should answer each question with affirmative or negative answers.

analysis of data
The data were described in terms of frequencies and analyzed using nonparametric statistics.The binomial test was employed to analyze the presence of significance in relation to the absence of signs and symptoms of deleterious oral habits and Spearman correlation analysis for the correlation between the variables: Age of the subjects with the severity of symptoms and the number of habits; severity of symptoms with a duration of TMD, with the frequency of signs and symptoms and the number of deleterious oral habits.

ReSultS
In this study, 65 out of 100 subjects had 21 to 40 years, 11 patients with less than 21 years and 24 subjects with more than 40 years.The time between the first symptoms reported by patients and the first assessment date in FORP/USP ranged from 1 to 23 years.
In this sample, there was significant presence of signs and symptoms of muscle pain, joint noise, fatigue, tinnitus, ear fullness, headache, difficulty opening the mouth, chewing and yawning impairment (p <0.01) and otalgia (p <0.05).A significant number of patients did not related difficulty to close the mouth.The frequencies and levels of significance are shown in Table 1.

Frequency of deleterious oral habits
Only four sample subjects reported no deleterious oral habits.Thirty-five reported 1 to 3 habits, while 61 subjects reported having 4 to 8 habits.There were reports of significant presence from diurnal and nocturnal clenching (p <0.01) and grinding of teeth at night (p <0.05).The other deleterious habits did not show significant presence in the sample or their absence were significant (Table 2).

Correlations
The age of subjects was positively correlated to the severity of muscle pain (r = 0.26, p <0.01), TMJ pain (r = 0.28, p <0.01), ear ache (r = 0.32, p <0.01), neck pain (r = 0.27, p <0.01) and tooth sensitivity (r = 0.28, p <0.01).Also the length of the TMD was related to the severity of muscle pain (r = 0.37, p <0.01), TMJ pain (r = 0.28, p <0.01), tinnitus (r = 0.21, p <0.05) and ear fullness (r = 0.21, p <0.05).There were positive and significant correlation between the number of symptoms and the severity of each TMD sign and/or symptoms (p <0.001).Sample distribution according to the severity of each sign and/or symptom, and the Spearman correlation coefficients are shown in Table 3.
The frequency of habits was negatively correlated with age of the subjects (r = 0.24, p <0.05).There was no significant correlation between the number of deleterious oral habits and TMD severity (p> 0.05).

dISCuSSIOn
The time between the first symptoms reported by patients and the date the first assessment in FORP/ USP ranged from 1 to 23 years, indicating that the treatment usually begins at the stage of chronic or recurrent disorder.duration of symptoms is far beyond the time established by the International Association for the Study of Pain (IASP) in 1994 23 to describe a clinical state of chronic pain, which would be at least 6 months history of pain, and more an attempt to unsuccessful treatment.
By the variety of symptoms present in TMD, it is common that people affected by the problem look different professionals and specialists such as neurologists, otorhinolaryngologists and general practitioners before arriving and/or referred to a specialist service in DTM, 11 which ends up making  treatment to be initiated already in a chronic stage of the disorder.This suggests the existence of difficulties in reaching the correct diagnosis and, consequently, to indicate the most appropriate treatment for each case, which in turn may be due to a lack of consensus on the methods of diagnosis, lack of preparation of professionals to recognize dysfunction and difficulty in identifying the etiology. 19,46In addition, there is the fact that many patients seek treatment only when the disorder is recognized by them due to the increased symptomatology.In this study, subjects were selected based on RDC/TMD, 9 which has been widely adopted as a method of classifying DTM. 8,9,42,45However, this is not the most appropriate method to understand the level of severity.Thus, we used the ProDTM-Multi previously constructed to standardize the records about the signs and symptoms of patients in multidisciplinary clinics, and to identify what are the signs and symptoms that affect the patient and their severity, and what are the most critical conditions on a daily basis. 13he significant presence of several signs and symptoms investigated in this study confirms the features found in other populations with TMD, 6,13,19,46 as well as the presence of significant reports of day and nighttime clenching and grinding of teeth at night. 30,31,32Although these are expected results, because it is a preselected population with TMD, it was interesting to note the patient's ability to affirm or deny what they felt, which complemented the clinical assessments effectively.So this is confirmed as a useful method to identify a dysfunction, 13 which can be easily applied by different health professionals, as is their proposal.
Among the deleterious oral habits, bruxism has been considered an important maintenance factor of TMD. 15,18,31,32,41The significant presence of diurnal and nocturnal clenching and teeth grinding (nocturnal) in this study, but not other habits, suggests the importance of bruxism on the progression and/or on non-remission of the disorder, being the clenching a more important risk factor than grinding. 6,15,30,31,40,41And while Choi and Choung Moon 6 have reported that bruxism cannot be a direct risk factor for TMD, there are reports showing that clenching was more often associated with TMJ symptoms and clinically relevant to the occurrence of the same, increasing the risk of manifestation of TMJ pain and noise and losses in the mouth opening. 17,22,24,29,44herefore, a likely association between bruxism and TMD signs/symptoms supports the theory that repetitive loads on the masticatory system can cause functional disorders. 3egarding the positive correlation observed between age and severity of signs and symptoms, it should be considered that only 24 sample subjects had more than 40 years.Therefore, it did not necessarily mean that the more advanced the age of the subject, the greater the severity of the pain present in the TMJ and muscles.As recognized in the literature, the age group most affected by TMD is the young and middle-aged adults. 3,7,10,19,39Epidemiological studies revealed that, unlike many other musculoskeletal conditions, the TMD has no increase in incidence or prevalence with increasing age. 19,25he higher frequency of TMD between 21 and 40 years of age over the older age groups was considered suggestive of the influence of psychological tensions that are inherent to the time of greatest productivity of these individuals, over the painful symptoms of TMD. 5 The duration of the TMD was correlated with muscle pain, TMJ pain and tinnitus and ear fullness.In the presence of pain and other symptoms, many compensations in the stomatognathic system can occur to allow that chewing, swallowing and speech might be carried out within the limit of efficiency and comfort.However, the actual compensation may have negative medium and long term effects, causing more imbalance and cumulative losses, because such compensations are not necessarily healthy 2,47 .Moreover, the process of chronic pain and the indiscriminate use of analgesics without medical control, as often occurs among patients with TMD, may worsen the case.20,37 Significant relationships have been found between the otologic symptoms and other TMD signs and symptoms, 4,38 as well as the functional difficulties of the stomatognathic system.12 In the present study, we observed that the perception of severity of ear pain was correlated with the age of subjects.Meanwhile, the consciousness of severity of tinnitus and ear fullness symptoms was correlated with the duration of TMD, suggesting their association with TMD and not agerelated ear problems.Earlier studies hypothesized that such symptoms may be caused by anatomical and functional relationships between the TMJ, the muscles innervated by the trigeminal nerve and the structures of the ear.1,27,33 The significant correlation between the frequency and severity of signs and symptoms are an indication that the larger the number of signs and Temporomandibular disorders and parafunctional oral habits: An anamnestic study original article symptoms, the greater the severity perceived by the patient.And, although several authors suggest that the habits accumulation can lead to worsening or contribute to no remission of the present scenario, and deleterious oral habits are among the TMD etiological factors, 15,19,30,31,32 the frequency of habits was not correlated to the frequency or severity of signs and symptoms, according to data analyzed from ProDTMMulti 13 in the current population.In a previous study, it was suggested that, in relation to bruxism, there is an effect of habit in time 30 .Probably the intensity and duration are more important than the number of habits.However, according to the limits imposed by the instrument used in this study, such measurement was not possible.
There were no significant presence of gum chewing habits and onychophagia in our sample, as well as the correlation between habits and age was negative.Research conducted with student populations pointed that gum chewing and onychophagia are the main habits and classified them as juvenile habits. 16,29he nature of this investigation allowed us to know about TMD symptoms in the light of who suffers it, revealing the possibility of using the protocol ProDTMMulti 13 as a tool for identification of a potential framework for TMD.Moreover, the possibility to register information about the awareness and consciousness of the population studied in relation to clenching and/or grinding of teeth facilitates the treatment plan, starting at the point of self consciousness to achieve some changes in behavior. 11

COnCluSIOn
Considering the limitations of an anamnestic study and based on the ProDTMMulti data, we conclude that the amount of signs and symptoms and their duration, may be predictive of the TMD severity, according to patients' own perceptions.Symptoms of day and nighttime clenching and nighttime grinding of teeth were significant, revealing the awareness and consciousness of the population studied in relation to them.And yet, the otologic symptoms of tinnitus and ear fullness were correlated with the time of dysfunction and not with age.However, such findings were based mainly on patients answers.A clinical investigation should be performed to confirm and generalize these findings.Furthermore, this study does not provide causal relationship, but only an association between the variables.Future work should be carried out to elucidate each topic individually.

Table 1 -
Frequency of TMD symptoms and noise signs present in the sample.Binomial test: *0.05 level of significance; **0.01 level of significance.

Table 2 -
Frequency of deleterious oral habits in the studied sample.

Table 3 -
Distribution of absolute frequencies of the severity of the TMD signs and symptoms and Spearman correlation coefficients (r) between the number of signs and symptoms and the severity of each one.