ASSOCIATIONS BETWEEN SCREENING FOR FUNCTIONAL JAW DISTURBANCES AND PATIENT REPORTED OUTCOMES ON JAW LIMITATIONS AND ORAL BEHAVIORS.

OBJECTIVES: Temporomandibular disorders (TMDs) is a collective term for pain and functional disturbances related to the jaw muscles and the temporomandibular joint. In contrast to screening for orofacial pain, knowledge is limited on the association between patient-reported outcomes and screening for joint-related functional jaw disturbances. Therefore, our aim was to evaluate the association between a screening question for functional jaw disturbances, and disease-specific outcome measures for functional jaw limitations and oral behaviors. METHODS: This study included 299 individuals (201 women; 20-69 years, median 37.0) in a general population sample from Västerbotten, Northern Sweden in 2014. A single screening question for functional jaw disturbances "Does your jaw lock or become stuck once a week or more?" was used to categorize individuals as cases or controls. Patient-reported outcomes on functional jaw disturbances were assessed with the 20-item jaw functional limitation scale (JFLS-20) and oral behaviors with the 21-item Oral Behaviors Checklist (OBC-21). RESULTS: The strongest predictive probability to have a positive screening outcome was functional jaw limitations related to mobility (AUCboot=0.78, 95 CI:0.71-0.86, P < .001), followed by limitations related to communication (AUCboot = 0.74, 95 CI:0.63-0.80, P < .001) and mastication (AUCboot = 0.73, 95 CI:0.66-0.81, P < .001). The frequency of oral behaviors was not significantly associated with a positive screening outcome (AUCboot = 0.65, 95 CI:0.55-0.72, P = .223). CONCLUSIONS: Self-reported functional limitations, but not oral behaviors, are strongly associated with a single screening question for frequent functional jaw disturbances. This finding provides support for incorporating a question on jaw catching/locking once a week or more in screening instruments for TMDs.

Effects on jaw function shortly after whiplash trauma.

Normal jaw function involves muscles and joints of both jaw and neck. A whiplash trauma may disturb the integrated jaw-neck sensory-motor function and thereby impair chewing ability; however, it is not known if such impairment is present shortly after a neck trauma or develops over time. The aim was to evaluate jaw function after a recent whiplash trauma. Eighty cases (47 women) were examined within 1 month after a whiplash trauma and compared to 80 controls (47 women) without neck trauma. Participants completed the Jaw disability checklist (JDC) and Neck Disability Index (NDI) questionnaires and performed a 5-minute chewing test. Elicited fatigue and pain during chewing were noted, and group differences were evaluated with Fisher's exact test and Mann-Whitney U-test. Compared to controls, cases had higher JDC (P < .0001) and NDI scores (15% vs 2%, P < .0001), and reported more fatigue (53% vs 31%, P = .006) and pain (30% vs 10%, P = .003) during the chewing test. Cases also had a shorter onset time for fatigue and pain (both P = .001) Furthermore, cases reporting symptoms during chewing had higher JDC and NDI scores compared to cases not reporting symptoms (both P = .01). Symptoms mainly occurred in the trigeminal area for both groups, but also in spinal areas more often for cases than for controls. Taken together, the results indicate that jaw-neck sensory-motor function is impaired already within 1 month after a whiplash trauma. The association between neck disability and jaw impairment underlines the close functional relationship between the regions, and stresses the importance of multidisciplinary assessment.

Outcome of three screening questions for temporomandibular disorders (3Q/TMD) on clinical decision-making.

Patients with temporomandibular disorders (TMD) seem to go undetected and not adequately managed within dentistry. To identify these patients, three screening questions (3Q/TMD) have been introduced within dentistry in parts of Sweden. It is not known whether 3Q/TMD affects the clinical decision-making for these patients. The aim of this study was to evaluate the outcome of 3Q/TMD on the clinical decision-making and to analyse whether gender, age and the fee system the individual was assigned to were related to prescribed TMD treatment. This cohort study was carried out within the Public Dental Health service in Västerbotten, Sweden. As part of the routine dental check-up, a health declaration including 3Q/TMD was completed. The study population was randomly selected based on their 3Q/TMD answers. In total, 300 individuals with an affirmative answer to any of the 3Q/TMD, and 500 individuals with all negative answers were selected. The 3Q/TMD includes questions on weekly jaw-face-temple pain (Q1), pain on function (Q2) and catching/locking of the jaw (Q3). The 3Q/TMD was analysed in relation to prescribed treatment assessed from dental records. There was significantly more treatment performed or recommended for 3Q-positives (21·5%), compared to 3Q-negatives (2·2%) (P < 0·001). The odds ratio for TMD-related treatment for 3Q-positives versus 3Q-negatives was 12·1 (95% CI: 6·3-23·4). Although affirmative answers to the 3Q/TMD was related to TMD treatment, the majority of individuals with a screen positive still did not, according to dental records, receive assessment or treatment. Further studies are needed to better understand the clinical decision-making process for patients with TMD.

Validity of three screening questions (3Q/TMD) in relation to the DC/TMD.

Temporomandibular disorders (TMD) are common but seem to be largely undetected within general dental care. To improve dentists' awareness of these symptoms, three screening questions (3Q/TMD) have been introduced. Our aim was to validate 3Q/TMD in relation to the diagnostic criteria for TMD (DC/TMD), while taking into account the severity level of the symptoms. The study population consisted of 7831 individuals 20-69 years old, who had their routine dental check-up at the Public Dental Health Service in Västerbotten, Sweden. All patients answered a health declaration, including the 3Q/TMD regarding frequent temporomandibular pain, pain on movement and catching/locking of the jaw. All 3Q-positives (at least one affirmative) were invited for examination in randomised order. For each 3Q-positive, a matched 3Q-negative was invited. In total, 152 3Q-positives and 148 3Q-negatives participated. At examination, participants answered 3Q/TMD a second time, before they were examined and diagnosed according to DC/TMD. To determine symptom's severity, the Graded Chronic Pain Scale and Jaw Functional Limitation Scale-20 (JFLS-20) were used. In total, 74% of 3Q-positives and 16% of 3Q-negatives met the criteria for DC/TMD pain or dysfunction (disc displacements with reduction and degenerative joint disorder were excluded). Fifty-five per cent of 3Q-positives had a TMD diagnosis and CPI score ≥3 or a JFLS-20 score ≥5, compared to 4% of 3Q-negatives. The results show that the 3Q/TMD is an applicable, cost-effective and valid tool for screening a general adult population to recognise patients in need of further TMD examination and management.

Jaw-opening accuracy is not affected by masseter muscle vibration in healthy men.

There is a functional integration between the jaw and neck regions with head extension-flexion movements during jaw-opening/closing tasks. We recently reported that trigeminal nociceptive input by injection of hypertonic saline into the masseter muscle altered this integrated jaw-neck function during jaw-opening/closing tasks. Thus, in jaw-opening to a predefined position, the head-neck component increased during pain. Previous studies have indicated that muscle spindle stimulation by vibration of the masseter muscle may influence jaw movement amplitudes, but the possible effect on the integrated jaw-neck function is unknown. The aim of this study was to investigate the effect of masseter muscle vibration on jaw-head movements during a continuous jaw-opening/closing task to a target position. Sixteen healthy men performed two trials without vibration (Control) and two trials with bilateral masseter muscle vibration (Vibration). Movements of the mandible and the head were registered with a wireless three-dimensional optoelectronic recording system. Differences in jaw-opening and head movement amplitudes between Control and Vibration, as well as achievement of the predefined jaw-opening target position, were analysed with Wilcoxon's matched pairs test. No significant group effects from vibration were found for jaw or head movement amplitudes, or in the achievement of the target jaw-opening position. A covariation between the jaw and head movement amplitudes was observed. The results imply a high stability for the jaw motor system in a target jaw-opening task and that this task was achieved with the head-neck and jaw working as an integrated system.

Pain and Disability in the Jaw and Neck Region following Whiplash Trauma.

The relationship between whiplash trauma and chronic orofacial pain is unclear, especially with regard to the time elapsed from trauma to development of orofacial pain. The aim was to analyze prevalence of jaw pain and disability, as well as the relationship between pain and disability in the jaw and neck regions in the early nonchronic stage after whiplash trauma. In this case-control study, 70 individuals (40 women, 30 men, mean age 35.5 y) who visited an emergency department with neck pain following a car accident were examined within 3 wk of trauma (group 1) and compared with 70 individuals (42 women, 28 men, mean age 33.8 y), who declined to attend a clinical examination but agreed to fill in questionnaires (group 2). The 2 case groups were compared with a matched control group of 70 individuals (42 women, 28 men, mean age 37.6 y) without a history of neck trauma. All participants completed questionnaires regarding jaw pain and dysfunction, rating pain intensity in jaw and neck regions on the Numerical Rating Scale, the Neck Disability Index, and Jaw Disability Checklist. Compared with controls, individuals with a recent whiplash trauma reported more jaw pain and dysfunction. Furthermore, there was a moderate positive correlation between jaw and neck pain ratings for group 1 (r = 0.61, P < 0.0001) and group 2 (r = 0.59, P < 0.0001). In the logistic regression analysis, cases showed higher odds ratios (range, 6.1 to 40.8) for jaw and neck pain and disability compared with controls. Taken together, the results show that individuals with a recent whiplash trauma report more jaw pain and disability compared with controls without a history of neck trauma. Furthermore, the correlation between jaw and neck pain intensity implies that intensity of neck pain in the acute stage after whiplash trauma might be a possible risk factor also for development of chronic orofacial pain.

Temporomandibular pain and jaw dysfunction at different ages covering the lifespan--A population based study.

BACKGROUND: Temporomandibular pain and jaw dysfunction can have a negative effect on daily life, but these conditions are not well recognized in the health care systems. The general aim was to examine the cross-sectional prevalence of frequent temporomandibular pain and jaw dysfunction in men and women across the lifespan. METHODS: The analysis was based on data from 137,718 individuals (mean age 35 years, SD 22.7) who answered three questions (3Q/TMD) included in the digital health declaration in the Public Dental Health care in the county of Västerbotten, Sweden; Q1: 'Do you have pain in your temple, face, jaw or jaw joint once a week or more?'; Q2: 'Does it hurt once a week or more when you open your mouth or chew?'; and Q3: 'Does your jaw lock or become stuck once a week or more?' RESULTS: The prevalence of frequent temporomandibular pain (Q1) was 5.2% among women and 1.8% among men (p < 0.0001). The prevalence of frequent pain on jaw movement (Q2) was 2.5% among women and 0.9% among men (p < 0.0001). The prevalence of frequent locking of the jaw (Q3) was 2.7% among women and 1.2% among men (p < 0.0001). CONCLUSIONS: The study shows that the cross-sectional prevalence of temporomandibular pain and jaw dysfunction varies during the lifespan. For men and women, respectively, symptoms increase during adolescence, peak in middle age and then gradually diminish. The prevalence of these symptoms is significantly higher among women except from the first and last decades of a 100-year lifespan.

The relationship between muscle tenderness and craniomandibular disorders: a study of 35-year-olds from the general population.

Of a random sample of 345 subjects aged 35 years and drawn from the general population of Västerbotten County, Sweden, 276 (80%) participated in an epidemiologic survey on muscle tenderness of the jaw, neck, shoulder, arm, hand, and calf, and on the prevalence of signs and symptoms of craniomandibular disorders. The control group consisted of 144 subjects (52%) who had no tenderness. The remaining subjects were separated into groups: (1) 59 subjects (21%) with tenderness only in jaw muscles; (2) 26 subjects (9%) with tenderness only in neck/shoulder muscles; (3) 39 subjects (14%) with tenderness in muscles of the jaw and neck/shoulder; and (4) eight subjects (3%) with tenderness in all palpated muscles of the neck, shoulder, arm, hand, and calf. Women were found to have palpation tenderness significantly more often than men (P < .05). The main finding of this study was the presence of a significantly higher proportion of signs and symptoms of craniomandibular disorders in the group who had both jaw muscle tenderness and neck/shoulder muscle tenderness and in the group who had generalized tenderness than in the control group. The results indicate that in epidemiologic and clinical research of craniomandibular disorders, a distinction between local, regional, and general tenderness should be made since the etiology may differ.

Relationship between signs and symptoms of mandibular dysfunction in adolescents.

The relationship between signs and symptoms of mandibular dysfunction was studied in 285 17-yr-old adolescents living in the municipality of Skellefteå, Sweden. Of the sample 62% had either some sign or symptom of dysfunction, and there was a positive correlation (P less than 0.05) between the two indices used. Neither morphologic nor functional malocclusions were related to the anamnestic dysfunction index. Signs of mandibular dysfunction were significantly more frequently found in those with a feeling of fatigue in the jaw (P less than 0.001). TMJ sounds were related to palpation tenderness in the lateral pterygoid muscle and to impaired horizontal mobility of the mandible. The most frequent symptom related to various signs of mandibular dysfunction was feeling of fatigue in the jaws which suggests that this is an early symptom of muscular origin that should be observed more closely. The study supports the view that even a moderate reduction of mouth opening capacity may indicate mandibular dysfunction and we recommend that this variable be routinely recorded.

Signs of osteoarthrosis of the temporomandibular joints in young patients: a clinical and radiographic study.

OBJECTIVE: The aims of this study were to investigate the occurrence of osteoarthrosis of the temporomandibular joints among young patients referred for consultation and treatment because of pain and dysfunction of the jaws and to study the relationship between signs and symptoms of temporomandibular disorders and osteoarthrosis in these patients. STUDY DESIGN: This was a retrospective study based on case histories, clinical examinations, and temporomandibular joint tomography. A total of 131 patients ranging in age from 12 to 30 years were included in the study. The null-hypothesis tested was that no significant differences in signs and symptoms of temporomandibular disorders would be found between joints with and joints without signs of osteoarthrosis. RESULTS: Osteoarthrosis of the temporomandibular joints was found in 87 patients (66%) and 151 joints (58%). The null-hypothesis was not rejected. CONCLUSION: A high prevalence of temporomandibular joint osteoarthrosis among the studied sample was found. The study did not allow us to draw any conclusions about the cause of temporomandibular joint osteoarthrosis in these patients. The result provided a basis for a subsequent follow-up study.

Craniomandibular disorders in adolescents. A longitudinal study in an urban Swedish population.

The prevalence of craniomandibular disorders was studied in 285 17-year-old adolescents with the aid of a questionnaire and a functional examination of the masticatory system including evaluation of TMJs, masticatory muscles, mandibular mobility, and occlusion. The adolescents were followed up longitudinally two more subsequent years. Totally 27 subjects dropped out, leaving 258 for the longitudinal intraindividual comparisons. At the age of 17 a fifth of the subjects reported some symptoms involving the masticatory system, of which most were mild, according to the anamnestic index (Ai) used. Oral parafunctions were commonly reported of which nail-biting dominated. Grinding and clenching of teeth were reported by 8% and 11% respectively. Signs of mandibular dysfunction were found in 56% of the adolescents and were mostly mild according to the dysfunction index (Di) used. Girls more often had signs of mandibular dysfunction than boys. Morphologic malocclusion was recorded in 35%, unilateral contact in RP in 77%, lateral shift between RP and IP greater than or equal to 0.5 mm in 19% and mediotrusion interferences in 30% among the 17-year-olds. No significant difference between sexes was found. Of the sample 62% had either some sign or symptom of dysfunction and there was a positive relationship between the dysfunction indices used. Neither morphologic nor functional malocclusions were related to the Ai. TMJ sounds were related to palpation tenderness in the lateral pterygoid muscle and impaired mobility of the mandible. The number of masticatory muscles tender to palpation was related to reports of fatigue in the jaw, TMJ tenderness, and mediotrusion interferences. Recurrent headache was reported by about 18% of the girls and by almost 6% of the boys. Fatigue in the jaws and difficulties in chewing were commoner in those with frequent and more intensive headache. Tenderness to palpation of the masticatory muscles and impaired mandibular mobility were significantly commoner findings among those with recurrent headaches and those with more intense headache. Tooth-grinding and clenching were related to frequency but not to intensity of headache. Reports of TMJ sounds increased with age for girls who also more frequently reported recurrent headaches than boys. The prevalence of symptoms of mandibular dysfunction was about 20% each year, but there was no general increase of frequency and severity of symptoms during the observation period in spite of an incidence of 8%. The prevalence was, according to the Ai, significantly higher for 18- and 19-year-old girls than for boys. Most symptoms were mild and fluctuated longitudinally.(ABSTRACT TRUNCATED AT 400 WORDS)

Experimental masseter muscle pain alters jaw-neck motor strategy.

BACKGROUND: A functional integration between the jaw and neck regions has been demonstrated during normal jaw function. The effect of masseter muscle pain on this integrated motor behaviour in man is unknown. The aim of this study was to investigate the effect of induced masseter muscle pain on jaw-neck movements during a continuous jaw opening-closing task. METHODS: Sixteen healthy men performed continuous jaw opening-closing movements to a target position, defined as 75% of the maximum jaw opening. Each subject performed two trials without pain (controls) and two trials with masseter muscle pain, induced with hypertonic saline as a single injection. Simultaneous movements of the mandible and the head were registered with a wireless optoelectronic three-dimensional recording system. Differences in movement amplitudes between trials were analysed with Friedman's test and corrected Wilcoxon matched pairs test. RESULTS: The head movement amplitudes were significantly larger during masseter muscle pain trials compared with control. Jaw movement amplitudes did not differ significantly between any of the trials after corrected Wilcoxon tests. The ratio between head and jaw movement amplitudes was significantly larger during the first pain trial compared with control. CONCLUSIONS: Experimental masseter muscle pain in humans affected integrated jaw-neck movements by increasing the neck component during continuous jaw opening-closing tasks. The findings indicate that pain can alter the strategy for jaw-neck motor control, which further underlines the functional integration between the jaw and neck regions. This altered strategy may have consequences for development of musculoskeletal pain in the jaw and neck regions.

Longitudinal course of symptoms of craniomandibular disorders in men and women. A 10-year follow-up study of an epidemiologic sample.

An epidemiologic sample (n = 285) drawn from the population of Skellefteå, Sweden, was examined to evaluate the prevalence of signs and symptoms of craniomandibular disorders (CMD) at the age of 17 years. The sample was then followed up prospectively at the ages of 18 and 19 years. The year they reached 28 years of age a questionnaire concerning prevalence, incidence, frequency, duration, location, and intensity of symptoms of CMD was sent to the same subjects. Two hundred and thirty-four subjects responded (82%). The number of subjects who participated in all examinations (at the ages of 17, 18, 19, and 28 years) was 215 (107 women and 108 men). During the 10-year period from the late teens onwards a significant increase in reported symptoms of CMD occurred in both men and women. For the whole sample the prevalence increased from approximately 20% to 37%. The incidence of CMD symptoms at the age of 28 years was 6% in both sexes. Although fluctuations of symptoms during the period from the age of 17 to 28 occurred in both sexes, the course of CMD in men and women differed significantly. All women who consistently reported symptoms at the age of 17-19 years also reported symptoms at the age of 28 years; the corresponding figure for men was 60%. At the age of 17 years 25 women reported CMD; 23 of these reported CMD at the age of 28 years (92%). At the age of 17 years 17 men reported CMD; 5 of these reported CMD at the age of 28 (29%). The result indicates different courses for CMD in men and women.

Etiology of craniomandibular disorders: evaluation of some occlusal and psychosocial factors in 19-year-olds.

This study involved 264 19-year-old adolescents who comprised 93% of an epidemiologic sample followed longitudinally from the age of 17. Case histories as well as self-ratings of anxiousness and comfort in daily living were collected with the aid of a questionnaire. The clinical examination included evaluation of TMJ, muscles, jaw mobility, and occlusion. The number of contacting teeth in the intercuspal position during light pressure was the occlusal factor with the most significant relationships to symptoms of mandibular dysfunction. Being tense was significantly related to a number of signs and symptoms of mandibular dysfunction. The risk ratio of having craniomandibular disorders was about three times as high in the group with few contacting teeth in the intercuspal area compared to those with the most occlusal contacts. The group who estimated themselves as tense had a risk ratio of craniomandibular disorders 3.4 to 8.5 times higher than those who did not experience tension. When the groups were constructed on the basis of combination of tension and few contacting teeth, these factors seemed to potentiate the risk ratios to values from 3.9 to 21 times those with most occlusal contacts and no experience of being tense.

Two-year longitudinal study of symptoms of mandibular dysfunction in adolescents.

Symptoms of mandibular dysfunction were followed up longitudinally from the age of 17 to 19 years in 285 adolescents. Totally, 27 subjects dropped out, leaving 258 for the longitudinal intraindividual comparisons. Reports of TMJ sounds increased significantly with age from 14% to 23% for girls, and at 19 years of age they significantly more often reported such sounds than boys. Girls also more frequently reported recurrent headaches (18%) than boys (1-6%). The prevalence of symptoms of mandibular dysfunction was about 20% each year, but there was no general increase of frequency and severity of symptoms during the observation period in spite of an incidence of 8%; new symptoms thus appeared as frequently as old symptoms disappeared. The prevalence of dysfunction was, according to the anamnestic index (Ai), significantly higher for 18- and 19-year-old girls. Girls also significantly more often reported more symptoms than boys, according to an accumulated index (AAi). Most symptoms were of mild character and fluctuated longitudinally. The need and demand for treatment may therefore be considered small. A routine stomatognathic screening is justified to identify those in need of treatment and those who should be observed more closely.

Two-year longitudinal study of signs of mandibular dysfunction in adolescents.

Signs of mandibular dysfunction in adolescents were studied longitudinally from the age of 17 to 19 years. Totally, 27 subjects dropped out, leaving 258 for the longitudinal intraindividual comparisons. TMJ sounds were found in about one-fifth of the adolescents and were recorded significantly more often in girls than boys from the age of 18 years. The frequency of muscles tender to palpation fluctuated somewhat between the annual examinations. At the first and second examination muscle tenderness was statistically significantly commoner in girls than in boys. Except for TMJ sounds and muscle tenderness signs of mandibular dysfunction were rare. About half of the subjects had signs of mandibular dysfunction, mostly of mild character. Girls regularly had significantly higher dysfunction index (Di) values than boys. No change between the annual recordings was noted in 60% of the individuals, and impairment and improvement had occurred about equally often. In 29%, signs were recorded all years.

Headache and dysfunction of the masticatory system in adolescents.

An epidemiologic group of 285 17-year-old adolescents was studied with the aid of a questionnaire for frequency and intensity of headache and for symptoms of dysfunction of the masticatory system. They were also subjected to a functional examination of the masticatory system. Recurrent headaches occurred significantly more often among the girls (18%) than the boys (6%). Girls also reported significantly more intense headaches than boys. Fatigue in the jaws and difficulties in chewing were commoner in those with frequent and more intensive headaches. Tenderness to palpation of the masticatory muscles and impaired mandibular mobility were significantly commoner findings among those with recurrent headaches and those with more intense headaches. Tooth-grinding and clenching were related to frequency but not to intensity of headache. The investigation showed a significant relationship between frequency and intensity of headaches and signs and symptoms of dysfunction of the masticatory system.

Need and demand for dental treatment. A comparison between an evaluation based on an epidemiologic study of 35-, 50-, and 65-year-olds and performed dental treatment of matched age groups.

The aim of this study was to compare the results of the level of treatment need as judged from a sample drawn from the general population aged 35, 50, and 65 years with treatments performed in 1992 and 1993 of patients of matched ages. Both the sample and the patients lived in Västerbotten in the northern part of Sweden. In all three age groups there was a significantly higher frequency of restorative treatment performed than the professionally assessed need in the epidemiologic sample. In all ages examined, treatment aimed at rehabilitation of temporomandibular disorders was performed statistically significantly (p < 0.001) less frequently than the evaluated need in the population. A similar result was found for dentures among 65-year-olds. The results may reflect dental care paradigms favoring operations on single teeth rather than treatments aimed at functional rehabilitation on a broader sense.

A century of controversy regarding the benefit or detriment of occlusal contacts on the mediotrusive side.

Many opinions have been presented in the literature during the past century regarding so-called mediotrusive/balancing/non-working side contacts. During the first half of this century, most authors advocated the advantage of these contacts (it was more or less the state of the art in prosthetic treatments), while during the last 50 years mediotrusive side contacts/interferences have mostly been regarded as a disturbing factor in the functioning of the mandible. Recently, it has been proposed that mediotrusive side contacts have a protective effect on the temporomandibular joint (TMJ). The aim of this study was to review opinions advocated during the twentieth century regarding the advantages and disadvantages of having contacts on the mediotrusive side during lateral excursions of the mandible. We conclude that, at present, there is no uniform body of scientific evidence supporting a balanced occlusion in favour of a mutually protective occlusion or vice versa. Longitudinal studies based on cohorts with different types of occlusal contacts, estimating the risk among these of developing signs and symptoms of temporomandibular disorders, are generally lacking and could provide valuable knowledge in this field.

Temporomandibular joint sounds in adolescents: a longitudinal study.

A 2-year longitudinal study on signs and symptoms of mandibular dysfunction was performed with 285 17-year-old adolescents living in a certain geographic area in Skellefteå, Sweden. Crepitation was neither reported nor recorded in any subject. Both reports and recordings of TMJ clicking sounds fluctuated with time. The 2-year period prevalence was 24%, and 5.8% consistently reported TMJ clicking sounds. The corresponding figures for clinically recorded clickings were 36% and 9.3%, respectively. Both reported and recorded joint sounds were significantly more frequently found in 19-year-old girls than in boys. No consistent pattern of relationships between reported and recorded clicking sounds and single factors obtained by the questionnaire or clinically recorded variables could be found. Palpation tenderness in three muscle sites was to a varying degree related to both reports and recordings of clicking. Each year, significant relationships were found between reports of TMJ sounds and symptom indices. Recorded sounds were significantly related to a clinical index in the two oldest age groups. The prevalence of TMJ clicking sounds increases with age, and girls are more prone to have them than boys. In view of the natural longitudinal fluctuations, most clickings only need to be supervised, and when there is a demand for treatment, reversible methods are advocated in adolescents.