Three-dimensional analysis of the cranio-cervico-mandibular complex during piano performance

Piano players, as well as other musicians, spend a long time training to achieve the best results, sometimes adopting unnatural body positions that may cause musculoskeletal pain. This paper presents the preliminary results of a study targeting the analysis of the head and cervical postures of 17 piano players during musical performance. It was found, as a common feature, that the players tilt the head to the right and forward towards the score and keyboard. Players who know the score by heart tend to move their heads more compared to the ones who have to keep their eyes on the score.

[The role of the cervical spine and the craniomandibular system in the pathogenesis of tinnitus. Somatosensory tinnitus]

The causes of tinnitus, vertigo, and hearing disturbances may be pathological processes in the cervical spine and temporomaxillary joint. In these cases, tinnitus is called somatosensory tinnitus (SST). For afferences of the cervical spine, projections of neuronal connections in the cochlear nucleus were found. A reflex-like impact of the cervical spine on the cochlear nucleus can be assumed. The tinnitus treatment concept of the Charité University Hospital in Berlin involves the cooperation of ENT specialists with many other disciplines in an outpatient clinic. A standardized examination protocol has been established, and physical therapy has been integrated into the interdisciplinary tinnitus treatment. For tinnitus-modulating therapy of muscular trigger points, local anesthetics as well as self-massage or treatment by a physiotherapist or osteopath are useful.

Reproducibility of jaw movements in patients with craniomandibular disorders

It has never been investigated, if mandibular movements of patients with craniomandibular disorders (CMD) result in a lower reproducibility of dynamic functional parameters which are used for the individual articulator setting. The aim of the present study was to compare the reproducibility of electronically registered functional parameters in patients with CMD and in a control group. Dynamic functional parameters were recorded in 30 patients and 30 volunteers with a computerized ultrasound system (ARCUSdigma). The whole registration was performed three times during one session and three times at a second session 1 week later. The horizontal condylar inclination in the patient group gave a standard deviation of 2.17 degrees +/- 0.95 degrees , indicating poorer reproducibility than in the volunteer group, for which the standard deviation was 1.37 degrees +/- 0.42 degrees . The reproducibility of measurements of the Bennett angle was also poorer in the patient group than in the volunteer group, with standard deviations of 1.70 degrees +/- 0.62 degrees and 1.22 degrees +/- 0.40 degrees , respectively. The standard deviations calculated for determination of incisal inclination during laterotrusion was 3.02 degrees +/- 1.49 degrees for patients and 2.30 degrees +/- 1.17 degrees for volunteers. The standard deviations for incisal inclination during protrusion was 2.02 degrees +/- 0.95 degrees for patients and 2.06 degrees +/- 1.82 degrees for volunteers. The reproducibility of measurement of horizontal condylar inclination, Bennett angle and incisal inclination during laterotrusion therefore showed significantly lower reproducibility in the patient group than in the volunteer group (P < 0.05). The overall reproducibility of the measurements was nevertheless good in both groups, with standard deviations under 3.1 degrees , so that an individual setting of an articulator seems useful even in patients with CMD.

[Stress, coping, and craniomandibular disorders]

BACKGROUND

Stress is an etiologic factor of pain-relevant craniomandibular disorders (CMD). Interindividual differences in coping with stress and their relation to CMD have rarely been examined.

PATIENTS AND METHODS

A total of 72 volunteers (20 men, 52 women) were examined according to the Research Diagnostic Criteria for Temporomandibular Disorders. Stress parameters and coping skills were assessed by questionnaires.

RESULTS

Stress and one coping factor are correlated with CMD indices. Linear regression analysis found the Life Event Score and cognitive coping by changing appraisals to significantly predict CMD.

CONCLUSION

Stress and coping skills are independent predictors of CMD.

Does head posture have a significant effect on the hyoid bone position and sternocleidomastoid electromyographic activity in young adults?

The aim of this study was to evaluate the associations between head posture (head extension, normal head posture, and head flexion) and anteroposterior head position, hyoid bone position, and the sternocleidomastoid integrated electromyographic (IEMG) activity in a sample of young adults. The study included 50 individuals with natural dentition and bilateral molar support. A lateral craniocervical radiograph was taken for each subject and a cephalometric analysis was performed. Head posture was measured by means of the craniovertebral angle formed by the MacGregor plane and the odontoid plane. According to the value of this angle, the sample was divided into the following three groups: head extension (less than 95 degrees); normal head posture (between 95 degrees and 106 degrees); and head flexion (more than 106 degrees). The following cephalometric measurements were taken to compare the three groups: anteroposterior head position (true vertical plane/pterygoid distance), anteroposterior hyoid bone position (true vertical plane-Ha distance), vertical hyoid bone position (H-H' distance in the hyoid triangle), and CO-C2 distance. In the three groups, IEMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing bipolar surface electrodes on the right and left sternocleidomastoid muscles. In addition, the condition with/without craniomandibular dysfunction (CMD) in each group was also assessed. Head posture showed no significant association with anteroposterior head position, anteroposterior hyoid bone position, vertical hyoid bone position, or sternocleidomastoid IEMG activity. There was no association to head posture with/without the condition of CMD. Clinical relevance of the results is discussed.

Impaired health status, sleep disorders, and pain in the craniomandibular and cervical spinal regions

This study investigated the relationship between health status (i.e., physical well-being and quality of life), sleep disorders (e.g., insomnia, sleep-related depression and anxiety), and musculoskeletal pain in the craniomandibular and cervical spinal regions. The number of painful body areas below the cervical spine (i.e., widespread pain) was also taken into account. Two questionnaires, viz., the RAND 36-item Health Survey Questionnaire and the Dutch Sleep Disorders Questionnaire (SDQ), were administered to 103 persons who could unequivocally be classified into one of four mutually exclusive groups: No pain, craniomandibular pain (CMP), cervical spinal pain (CSP), and both CMP and CSP. Body drawings were used for the self-report of widespread pain. Multivariate analysis of variance showed effects of gender, group, and widespread pain on the questionnaire scales; not of age. As shown by univariate analysis of variance, men suffered more from sleep apnea than did women. No other gender differences were found. Simple contrast analyses following univariate analyses of the group and widespread pain effects showed that, in general, more questionnaire scales, both of the RAND-36 and of the SDQ, reached statistical significance with an increase in the number of painful areas. It was concluded that both musculoskeletal pain in the trigemino-cervical area and widespread body pain are associated with an increased impairment of health status. Also, sleep disorders are frequently found in patients with chronic pain in the craniomandibular and cervical spinal regions as well as in patients with widespread pain. The more painful areas there are, the likelier it is that sleep disorders are present.

[Muscular-arthroscopic pain: often unappreciated]

Myoarthropathic pain, most often due to masticatory myalgia, is the major source of orofacial pain. Its diagnosis is not always easy because the diagnostic signs are not pathognomonic and they may occur also with other pain disorders. The pain intensity fluctuates, and mild to medium intensity pain has the tendency to subside spontaneously or can be alleviated with simple, non-invasive therapies such as counseling, self-control, analgesics, physiotherapy, and occlusal appliances. For most patients a combination of counseling, self-control and physiotherapy (home program) is sufficient to relieve the pain. Occlusal appliances should, therefore, be used only if these modalities fail or if pain is present on awakening. Only in a small percentage of patients the myoarthropathic pain persists and becomes chronic. The factors that determine pain chronicity are complex and most likely due to the interaction of biomedical factors - such as the persistence of peripheral nociceptive input, neuroplastic changes at spinal and supraspinal levels (cortical reorganisation)- with psychosocial factors, in addition, possibly, to a polymorphism of the catechol-o-methyltransferase gene. Patients with chronic myogenic pain need a multimodal therapy, according to the biopsychosocial pain model. In addition to the modalities just described, the treatment must address also the affective, emotional, cognitive and behavioural pain component and be tailored to the single patient based on his/her psychosocial and constitutional characteristics. The goal is not pain relief but improvement of the quality of life by teaching the patient more efficient pain coping strategies by means of behavioural and relaxation techniques. In addition, tricyclic antidepressants may be used in order to treat the somatic pain component caused by the neuroplastic changes that take place in the central nervous system in chronic pain conditions.

[The influence of occlusion on sporting performance]

AIM

The purpose of the present study is to investigate the relationship between dental occlusion and physical performance using the Ergo-jump platform, and to highlight connections, if any.

METHODS

For the purpose of this research, 30 patients suffering from cervico-facial pathology and 10 without temporomandibular joint dysfunction were selected from within the Dental Clinic of the University of Sassari. For the first group a resin plate was prepared to correct the malocclusion, while for the control group a bite was prepared that created it. Subjects carried out exercises with the Ergo-jump platform, a device that assesses physical capabilities and athletic performance. Patients were asked to do 2 exercises, a counter movement jump and a mechanical power test, with plate and without plate.

RESULTS

The tests of the first group were as follows: flying times with the bite were 0.01 s longer; the average elevation in the counter movement jump test did not give statistically significant results; execution of the mechanical power test suggests an increase in average mechanical power with the plate. Execution of the same exercises in the other group showed greater flight times without the place; average elevation was not statistically significant; the execution of the mechanical power test showed a decrease in average mechanical power with the occlusion plate.

CONCLUSION

Statistical analysis of individual results showed that patients do not always obtain a benefit during physical exercise using the bite. Research shows that the same pathology can cause different physical performance in different individuals; in fact, not all craniomandibular disturbances have repercussions on posture.

Combined effect of vestibular and craniomandibular disorders on postural behaviour

A correlation has been reported in the dental literature between temporomandibular disorders and musculoskeletal abnormalities, however, the question whether they modify body postural sway remains controversial. In the present investigation, the Craniomandibular Index was used to evaluate the clinical extension of temporomandibular joint dysfunction and related problems in 40 patients with normal vestibular function and in 42 patients with peripheral vestibular disorders. Balance function was assessed by static posturography and body sway area was measured in two conditions: i) eye open, and g) eye closed. Data were compared to those of 40 healthy subjects. Postural control showed a significantly different behaviour between groups with an increase in average body sway in patients with craniomandibular disorders as opposed to controls (p < 0.005). Although the involvement of the stomatognathic apparatus was not quantitatively different in the two groups of patients, those also presenting a peripheral vestibular disorder exhibited greater average body sway than patients with only craniomandibular disorders (p < 0.005). The latter showed a greater average body sway than controls only in the trial with eyes closed (p < 0.05). The results demonstrated that craniomandibular alterations could produce moderate postural instability in patients with a normal vestibular function. Conversely, their association with peripheral vestibular disorders becomes a real challenge to the upright quiet stance probably due to a negative effect of somatosensory origin on the vestibulo-spinal reflex impairment.

[Do temporomandibular disorders really exist?]

Temporomandibular Disorders (TMD) is a collective term embracing a number of clinical problems that involve the muscles of mastication, the temporomandibular joint (TMJ) and associated structures or both. This group of disorders has been identified as the chief cause of pain, which is not of dental origin, in the orofacial area, and is defined as a subgroup in the category of musculoskeletal disorders. These disorders impair the quality of life of those suffering from them due to the extent of the pain and the chronic nature of its symptoms. It is known that chronic pain causes the development of psychological disturbances (anxiety, depression, etc.). The most common symptoms of TMD are the pain that usually appears as the result of mandibular activity (speaking or chewing), and is usually located in the masticulatory muscles, in the preauricular area and the temporomandibular joint (TMJ). Additional common symptoms are: a. restriction in jaw movement; b. asymmetry in jaw movement; c. noises from the joint. Patients suffering from TMD are likely to exhibit additional symptoms: hypertrophy of the muscles of mastication (an adaptive and asymptomatic phenomenon), abnormal occlusar erosion due to nighttime or daytime bruxism, or teeth grinding. Most functional temporomandibular disorders have similar signs and symptoms. As a result, diagnosis of the various disorders presents a serious problem. Functional temporomandibular disorders are often accompanied by mental symptoms such as depression, anxiety and/or somatization on various levels. One of today's accepted methods of classification also refers to the mental aspect and thus enables, for the first time, a suitable scientific comparison of the epidemiological, diagnostic and treatment data in the various studies. This method, initiated by Dworkin and LeResche (1992) is known as Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). The purpose of this method is to classify every subgroup of TMD according to agreed upon, clear and measurable diagnostic criteria, both from the physical (AXIS I) and the mental (AXIS II) aspect. The method includes a scale which grades the extent of severity, damage and limitations caused by the illness, in a manner which now can make scientific comparisons between the various studies and between the population of patients and the general population. Temporomandibular disorders are very common and affect between 30%-50% of the population, and appear to be more prevalent among women than among men. Studies conducted on youth revealed significant relationships between oral parafunctions (especially chewing gum and "jaw playing"), and functional temporomandibular disorders. The significance of this finding is in the need to warn young people of the possible risks of engaging in intensive oral practices. The high prevalence of signs and symptoms among the Israeli population obligates us, in our opinion, to change the physical examination for identification of these disorders, to a routine procedure in all dental clinics in Israel.

The influence of voluntary muscle contractions upon the onset and modulation of tinnitus

OBJECTIVE

To evaluate the frequency of tinnitus onset (in normal subjects) and modulation (in tinnitus patients) during muscle contractions, estimating possible risk factors.

MATERIAL AND METHOD

This case-control study enrolled 121 tinnitus patients and 100 healthy volunteers who underwent medical history, ENT examination and 16 maneuvers of muscular contraction (head, neck and limbs). Modulation data were compared between patients with and without normal audiometry, well-defined diagnosis and symptoms of craniomandibular disorders.

RESULTS

The ability to modulate tinnitus (65.3%) was significantly higher than that to originate tinnitus (14.0%). The head and neck musculature was significantly more efficient than that of the limbs. Audiometric pattern, well-defined etiology and symptoms of craniomandibular disorders showed no relation to tinnitus modulation.

CONCLUSIONS

Somatic modulation is a characteristic aspect of tinnitus.

Masticatory performance in patients with anterior disk displacement without reduction in comparison with symptom-free volunteers

Masticatory function can be impaired by craniomandibular disorders. The aim of this study was to assess masticatory performance in patients with an anterior disc displacement (ADD) without reduction. In the experiments, 29 patients and 33 age- and gender-matched volunteers chewed artificial test food for 60 chewing strokes. The collected remains of the test food were filtered, dried, fractionated by a sieving procedure, and weighed. The particle size distribution was then described using a cumulative distribution function. Patients and controls were clinically examined, and patients were asked to complete a pain questionnaire. Comparison with controls, patients showed significantly reduced masticatory performance. Patients that had had a disorder longer than 3 yr tended to display less reduction of their masticatory performance. Neither the treatment methods used, nor restriction of daily life activities or pain intensity were significantly correlated with masticatory performance. Jaw mobility was significantly reduced in patients. More than half of the patients and none of the controls had joint noises and trigger points in the masticatory muscles. Pain was present, in particular, during chewing and maximal opening of the mouth. It was concluded that patients with ADD without reduction have a significantly reduced masticatory performance.

Multifactorial analysis of the aetiology of craniomandibular dysfunction in children

OBJECTIVES

It is generally accepted that the aetiology of craniomandibular dysfunction (CMD) is multifactorial. Different types of malocclusion, oral parafunctions especially bruxism, trauma of the mandible or temporomandibular joint (TMJ) and emotional stress are known aetiologic factors. Research has been conducted into the relationship between each of these aetiologic factors and the signs and symptoms of CMD. However, such an approach does not control for the simultaneous effect of other factors responsible for the development of the dysfunction. The purpose of this study was to investigate the effect of each aetiologic factor on the signs and symptoms of CMD in children, controlling for the effect of all other known factors by means of a multifactorial analysis.

METHODS

A sample of 314 children, aged 6-8 years, was examined clinically for signs of CMD and morphologic and functional malocclusion. Symptoms of CMD and oral parafunctions were recorded by the same investigator in an interview. Emotional stress was measured through urinary catecholamines including epinephrine, norepinephrine and dopamine, detected in a 24-h urine sample, using high performance liquid chromatography. A questionnaire was distributed to the parents to collect information regarding socioeconomic factors and the history of dentofacial injuries. A logistic multiple regression was carried out to estimate the partial effect of each aetiologic factor. A 95% probability level was used.

RESULTS

Posterior crossbite with lateral shift significantly affected the probability of child developing deviation of the mandible on opening. Similarly, posterior crossbite and epinephrine had a significant impact on TMJ tenderness, overjet had an effect on clicking, clenching and biting of objects had an effect on muscle tenderness, and lip/cheek biting influenced dysfunctional opening. Of the symptoms reported, pain on wide opening was affected significantly by lip/cheek biting.

CONCLUSION

On the basis of these results, it can be suggested that parafunctional and some structural and psychological factors may increase the probability of the child developing the signs and symptoms of CMD.

[Stabilimetry and cranio-cervico-mandibular disorders]

BACKGROUND

Cranio-cervico-mandibular disorders can cause disturbances in posture. Stabilimetry measures spatio-temporal variations in the center of body pressure and evaluates the mechanisms of maintenance of balance. The study used a stabilimetric platform to evaluate posture changes in patients with cranio-cervico-mandibular disorders before and after treatment for malocclusion.

METHODS

Between February 1998 and December 2000, 60 patients with cranio-cervico-mandibular disorders were recruited from the Dentistry Clinic of the University of Sassari. Each patient underwent two stabilimetric examinations (closed mouth with cotton wads inserted between the dental arches). The tests were conducted on a stabilimetric platform. Measurement of body posture load and sway were analyzed with a specific software program that correlated the vestibular, somatosensory and visual systems, and determined the role of each in postural control.

RESULTS

The stabilimetric analysis showed that the adoption of the plaque allowed rebalance of the postural system, without affecting the visual system. After treatment, 64% of patients experienced remission of pain symptoms with orthotic therapy.

CONCLUSIONS

The relationship between malocclusion and posture should be seen from a holistic standpoint in other to gain a global therapeutic outcome.

Magnetic resonance imaging findings of internal derangement and effusion in patients with unilateral temporomandibular joint pain

OBJECTIVES

The purpose of this study was to investigate the relationship between the presence of temporomandibular joint (TMJ) pain and the magnetic resonance (MR) imaging findings of internal derangement (ID) and effusion.

STUDY DESIGN

The study was comprised of 41 consecutive patients with TMJ pain. Criteria for including a patient were report of unilateral pain near the TMJ, with the presence of unilateral TMJ pain during palpation, function, and/or unassisted or assisted mandibular opening, and the absence of a specific clinical TMJ-related diagnosis of disk displacement with or without reduction. Bilateral sagittal and coronal MR images were obtained to establish the presence or absence of TMJ ID or effusion, or both.

RESULTS

Comparison of the TMJ side-related data showed a significant relationship between the clinical finding of TMJ pain and the MR imaging diagnoses of TMJ ID (P =.001), and TMJ effusion (P =.004). Furthermore, there was a significant relationship between the MR imaging diagnosis of TMJ ID and TMJ effusion (P =.000). Use of the kappa statistic test indicated poor diagnostic agreement between the presence of TMJ pain and the MR imaging diagnosis of TMJ ID (kappa = 0.34), TMJ effusion (kappa = 0.32), and TMJ ID and effusion (kappa = 0.27).

CONCLUSIONS

The study's findings suggest that although clinical pain is correlated with TMJ-related MR imaging findings, clinical pain in and of itself is not reliable for predicting the presence of TMJ ID or effusion, or both. Therefore, MR imaging appears to be a warranted and necessary supplement to the clinical findings.

Emotional stress and craniomandibular dysfunction in children

This study investigated the relationship between craniomandibular dysfunction (CMD) and emotionally stressful states measured by the urinary catecholamines in 314 children aged six to eight years. The children were examined clinically and interviewed by the same investigator. During the clinical examination the following variables were recorded: maximal mouth opening with and without pain, deviation of the mandible in opening wide, muscle and temporomandibular joint (TMJ) tenderness or pain and sounds from the TMJ. The variables recorded during the interview were headaches, difficulties in opening wide, pain upon opening wide, and clicking. A questionnaire was distributed to the parents to collect information regarding socioeconomic factors. A 24-hour urine sample was collected for each subject and analyzed by the high performance liquid chromatography (HPLC) technique to assay the catecholamine content. The logistic multiple regression analysis was carried out to test whether craniomandibular dysfunction was affected by the studied variables. A 95% probability level was used. The results showed that epinephrine had a significant effect on TMJ tenderness, while norepinephrine and dopamine did not have a significant association with any of the signs and symptoms of CMD. The data suggest that emotionally stressful states increase the probability of developing TMJ tenderness in children of this age.

Effect of a thick palatal appliance on muscular symptoms in craniomandibular disorders: a preliminary study

Several treatment modalities for myofascial pain dysfunction syndrome (MPD) are being used at present. However, from the standpoint of patients' quality of life, it would be reasonable to seek a more effective treatment modality. This study aimed to show clinical data of a preliminary study regarding the effect of a thick palatal appliance, designed to fill the palatal concavity with a thick resin base, on muscular symptoms in eighteen MPD patients. Shown here are the clinical results of two volunteer patients using palatal appliances of two different thicknesses. In this study, MPD patents were divided into the three following groups: 1. no-treatment group; 2. thick palatal appliance group; and 3. medication group. Based on the results of this study, it was suggested that the thick palatal appliance could bring about early improvement of MPD syndrome. It is suggested that the thickness of the palatal plate was an important factor in obtaining the clinical effect.

Effects of head and neck inclination on bilateral sternocleidomastoid EMG activity in healthy subjects and in patients with myogenic cranio-cervical-mandibular dysfunction

This study was conducted in order to determine the effect of head and neck position on bilateral electromyographic (EMG) activity of the sternocleidomastoid muscles. The study was performed on 16 patients with myogenic cranio-cervical-mandibular dysfunction (CMD) and 16 healthy subjects. EMG recordings at rest and during swallowing of saliva and maximal voluntary clenching were performed by placing surface electrodes on the right and left sternocleidomastoid muscles. EMG activity was recorded in the left lateral decubitus position, in a darkened room and with the individual's eyes closed, under the following experimental conditions: 1. Head, neck, and body horizontally aligned; 2. Head and neck upwardly inclined with respect to the body, simulating the effect of a thick pillow, 3. Head and neck downwardly inclined with respect to the body, simulating the effect of a thin pillow. Variation of head and neck positions was determined by measuring the distance from the angle of neck and shoulder and the apex of the shoulder (SND = shoulder-neck distance) of each individual. Then, head and neck were forward or downwardly inclined with respect to the body at one-third of SND. A significantly higher contralateral EMG activity and a more asymmetric EMG activity were observed in the CMD group than in the healthy subjects (Kruskal-Wallis Test). These results suggest a different behavior of bilateral sternocleidomastoid EMG activity in CMD patients than in healthy subjects depending on the positioning of the head and neck.

Relationship between craniomandibular disorders and poor posture

The purpose of this research was to show that a relationship between craniomandibular disorders (CMD) and postural abnormalities has been repeatedly postulated, but still remains unproven. This study was intended to test this hypothesis. Twenty-five CMD patients (mean age 28.2 years) were compared with 25 gender and age matched controls (mean age 28.3 years) in a controlled, investigator-blinded trial. Twelve postural and ten muscle function parameters were examined. Measurements were separated into three subgroups, consisting of those variables associated with the cervical region, the trunk in the frontal plane, and the trunk in the sagittal plane. Within these subgroups, there was significantly more dysfunction in the patients, compared to control subjects (Mann-Whitney U test p < 0.001, p < 0.05, p < 0.01). Postural and muscle function abnormalities appeared to be more common in the CMD group. Since there is evidence of the mutual influence of posture and the craniomandibular system, control of body posture in CMD patients is recommended, especially if they do not respond to splint therapy. Whether poor posture is the reason or the result of CMD cannot be distinguished by the data presented here.

Headache and cranio-mandibular disorders during adolescence

A clinical and epidemiological investigation was performed on 62 adolescents, 21 males and 41 females, with recurring headaches, in order to analyze the connections between the cephalalgia and the signs and symptoms of mandibular dysfunction. The anamnestic and objective data were reviewed with the aid of the Helkimo indices and compared to data on a control group of comparable age who were not headache sufferers. The most statistically significant signs encountered (p < 0.001) were: pain on palpation of masticatory muscles (61%), altered (43%) or reduced (27%) mandibular movement, preauricular tenderness (19%); the high incidence of parafunctions indicated the behavioral substrate. This pilot study reveals a link between the two pathologies and the need for early diagnosis, preventive identification of the subjects at risk and interdisciplinary cooperation.

[Effects of muscular position splint on maxillomandibular realignment]

OBJECTIVE

To study the effects of muscular position splint on maxillomandibular realignment.

METHODS

The changes of occlusal impression on splint in 102 craniomandibular disorder (CMD) patients were recorded after wearing the splint 1 week, 2 weeks, 1 month, two to three or six months. If there appeared instability of occlusal impression when biting, the original impression was cleared and new soft resin was placed on its surface in order to get a new impression. The splint was always adjusted to fit well. When the signs and symptoms of CMD disappeared, the splint was worn off. Finally, whether the muscular contact position harmonized with the intercuspal position (ICP) or not was recorded.

RESULTS

There appeared two different conditions: 1. The original occlusal impression remained unchanged in 66 patients; 2. Being unfitted in 36 patients, occlusal analysis revealed that 12/102 patients had abnormal occlusion including premature anterior teeth contact (2 cases), natural defective vertical dimension (1 case) and deflected ICP (9 cases). These abnormal occlusion could not be determined before treatment.

CONCLUSION

The muscular position splint can correct the abnormal muscular position. On the premise that the muscular position is normal, the muscular position splint can be used to judge whether the ICP is normal.

Nocturnal masseter EMG activity of healthy subjects in a natural environment

Facial pain of patients with craniomandibular disorders might be caused by muscle overload. However, the activity of masticatory muscles of healthy individuals is still unknown. The aim of this study was therefore a first attempt to clarify this question by recording the masseter muscle activity of healthy subjects during sleep by means of portable recorders. The study was performed on 21 healthy subjects selected after telephone and questionnaire screenings and clinical examination from among randomly selected inhabitants of Zürich. The masseter EMG was recorded during seven nights in each subject's natural environment with the electrodes in reproducible position. The signal was analyzed for number, amplitude, and duration of contraction periods defined as signal portions above a threshold which could contain sub-threshold signal portions shorter than the standby time of 5 sec. The signal amplitude was expressed in percent of the amplitude recorded during maximum voluntary clenches (%MVC). An average of 71.9 +/- 28.7 contraction episodes per night (men, 74.7 +/- 30.1; women, 65.0 +/- 23.8; p = 0.043), i.e., of 10.5 +/- 3.8 per hour (men, 11.0 +/- 4.0; women, 9.3 +/- 3.0; p = 0.005), was found. The average mean amplitude was 26.2 +/- 6.4% MVC (men, 27.0 +/- 6.8; women, 24.4 +/- 4.5; p = 0.009). The duration of the episodes had a mode of 0.5 sec, and the group mean of the integral of the amplitude over time was 123.7 +/- 157.9% MVC (men, 138.9 +/- 184.0; women, 85.9 +/- 28.2; p = 0.005). Healthy subjects showed intermittent periods of masseter activity during sleep which, on average, were of rather low intensity and short duration.

Breathing obstruction in relation to craniofacial and dental arch morphology in 4-year-old children

The prevalence of breathing obstruction was determined in a cohort of 4-year-old children. Craniofacial morphology was studied in obstructed children and compared with data from a control group of 4-year-old children with ideal occlusion. Dental arch morphology was compared in obstructed and non-obstructed children in the group. Parents of 95.5 per cent of the study base of 644 children answered a questionnaire concerning their child's nocturnal behaviour and related questions. The 48 children who, based on parental report, snored every night or stopped breathing when snoring (the 'snoring group'), showed a higher rate of disturbed sleep, mouth-breathing, and a history of throat infections as compared with the rest of the cohort. These children were examined by both an orthodontist and an otorhinolaryngologist and, when indicated, they were also monitored in a sleep laboratory. Twenty-eight of the children were diagnosed as having a breathing obstruction (4.3 per cent of the cohort) and six children (0.9 per cent) had sleep apnoea (mean apnoea-hypopnoea index of 17.3), using the same definition as that for adults. Cephalometric values among the obstructed children differed from those of a Swedish sample of the same age with ideal occlusion. Thy had a smaller cranial base angle and a lower ratio of posterior/anterior total face height. Small, but not significant differences were seen for NSL-ML and NL-ML. Compared with 48 asymptomatic children from the same cohort, the obstructed children had a narrower maxilla, a deeper palatal height, and a shorter lower dental arch. In addition, the prevalence of lateral crossbite was significantly higher among the obstructed children.

[Changes in the craniomandibular relations of acromegaly patients]

The dishomeostazical theory (etiopathogenic integrative concept) allows an ample and complex vue on the stomatognathic system dysfunctional syndrome, because it begins from the perception of the stomatognathic system (SS) as a whole in which the alteration of each element can induce the disfunction of the entire system. The purpose of this study is to demonstrate that the neuroendocrine suprasystemic factor (STH hypersecretion on adult organism) disturbs every element of the SS and induces an important alteration of the fundamental cranio-mandibular relations.

Concurrent cervical and craniofacial pain. A review of empiric and basic science evidence

Because many patients present themselves for treatment with both craniofacial and craniocervical pain, 2 questions arise: (1) What are the sensory and motor consequences of dysfunction in either of these areas on the other? (2) Do craniofacial and craniocervical pain have a similar cause? These questions formed the impetus for this review article. The phenomenon of concurrent pain in craniofacial and cervical structures is considered, and clinical reports and opinions are presented regarding theories of cervical-to-craniofacial and craniofacial-to-cervical pain referral. Because pain referral between these 2 areas requires anatomic and functional connectivity between trigeminally and cervically innervated structures, basic neurophysiologic and neuroanatomic literature is reviewed. The published data clearly demonstrate neurophysiologic and structural convergence of cervical sensory and muscle afferent inputs onto trigeminal subnucleus caudalis nociceptive and non-nociceptive neurons. Moreover, changes in metabolic activity and blood flow in the brainstem and cervical dorsal horn of the spinal cord in both monkeys and cats have been demonstrated after electric stimulation of the V1-innervated superior sagittal sinus. In conclusion, the animal experimental data support the findings of human empiric and experimental studies, which suggest that strong connectivity exists between trigeminal and cervical motor and sensory responses.

Myoelectric activity during unilateral chewing in healthy subjects: cycle duration and order of muscle activation

STATEMENT OF PROBLEM

Craniomandibular disorders, unilateral mastication, and asymmetry of masticatory muscles appear to be related to each other. Thus, it is of interest to investigate masticatory muscle activity during unilateral mastication in healthy subjects.

PURPOSE

This study monitored contractile activity of the right and left masticatory muscles during right- and left-side gum chewing.

MATERIAL AND METHODS

Electromyographic techniques were used to determine chewing cycle duration and duration of contractile activity of the masticatory muscles (right and left masseter and anterior temporalis muscles) during unilateral chewing in 40 subjects without orofacial pain. The time-course of activation of the 4 muscles was also investigated.

RESULTS

Electromyographic traces showed extensive interindividual variation. In both right- and left-side chewing tests, and regardless of whether the masseter or the temporalis muscles were considered, mean duration of the contraction phase did not differ significantly between the working and nonworking sides. The working side temporalis contracted first, whether alone or at the same time as the other muscles.

CONCLUSIONS

In healthy subjects, no significant differences in masticatory muscle activity should be expected between either the right and left or the working and nonworking sides.

Relationship between juvenile bruxing and craniomandibular dysfunction

A longitudinal study was conducted over 5 years to investigate the relationship between juvenile bruxing and craniomandibular disorders. A total of 150 bruxers between the ages of 6 and 9 years were examined for oral parafunctions and TMJ symptoms. Of these, 126 were re-examined for the same signs and symptoms after 5 years. The results showed that only 17 individuals had retained their bruxing habit. In common with other studies, we found that symptoms reduced with age. It was concluded that juvenile bruxing was a self-limiting condition which does not progress to adult bruxism and which appeared to be unrelated to TMJ symptoms.

[Clinical evaluation and psychological aspects of temporomandibular joint disorders]

Establishing the patient's clinical diagnosis depends on gathering as much information of the patient and his or her signs and symptoms as possible. This information can be gathered from history, physical and psychological examination, diagnostic analysis. It is also important to look upon pain as a disorder and to consider the relationship between pain and psychological factors. The differential diagnosis is constructed through a biopsychological model of illness rather than through a more traditional biomedical model of disease. To arrive at a consistently accurate clinical diagnosis in patients with TMJ and craniofacial pain, the technique of clinical diagnosis must be well defined, reliable and include examination of the head and the neck, cranial nerves and the stomatognathic system. The craniomandibular index provides a standardized examination of the stomatognathic system that has been tested on validity and reliability. This chapter focuses on the techniques of history taking clinical and psychological examination and diagnostic criteria for temporomandibular joint disorders and muscle pain.

Automatic on-line one-channel recognition of masseter activity

The etiology of myoarthropathies of the masticatory system (MAP) is not fully understood. For the hypothetical association between the myogenous pain of MAP patients and masticatory muscle overuse to be proved, functional and parafunctional behavior of the masticatory muscles should be analyzed in normal and diseased subjects. The aim of this study was to test on-line the validity and reliability of an algorithm, applied to the electromyographic signal, to recognize various oral activities. The surface electromyogram of the masseter muscle was recorded in 12 subjects (seven females and five males, from 18 to 32 years old) who performed a series of functional and parafunctional activities (chewing soft food, chewing hard food, swallowing, laughing, speaking, and tooth grinding and clenching), as well as no activity. During the computer training phase, intra-individual classification functions of a multivariate discriminant analysis were calculated while each subject performed the described activities. During the test phase, each subject repeated the same activities, and the computer continuously classified them on-line. The percentage of correctly recognized activities was calculated for each activity and for each subject. No activity, chewing hard food, swallowing, laughing, grinding, and clenching were recognized correctly > 99% of the time. Chewing soft food was recognized correctly 97% and speaking 86% of the time. The sensitivity values for the recognition rates of the complete oral activities were, with one exception, > 0.82; the specificity values were > 0.95, and the kappa-values > 0.80. These results show that the algorithm had high sensitivity, specificity, and reliability in the classification of different oral activities under laboratory conditions.

[The development of craniomandibular disorders after bilateral sagittal osteotomy]

The aim of this study is to know the repercussions of modified sagittal ramus split osteotomy of the mandible on the anamnesic symptoms of cranio-mandibular disorders in 89 patients. The sample was divided into different groups according to the surgery type: mandibular advancement or mandibular retrusion with or without maxillary surgery. The anamnesic approach allows to evaluate the felt symptoms. All had a surgery by the same surgeon and with the same technique: mandibular sagittal bilateral surgery according to the modificated Obwegeser osteotomy. The statistical analysis shows some differences between groups.

[The contribution of standard radiographs in the evaluation of masticatory system dysfunction]

Conventional x-ray films (orthopantomogram, teleradiogram) visualize many signs of dysfunction of the manducatory apparatus (DAM). Progress in our knowledge of the pathophysiology of DAM has brought new light to these radiographic signs. The orthopantomogram allows an assessment of modifications in muscle insertion zones secondary to their dysfunction and, more difficulty, the articular remodeling of the TMJ, mainly of the mandibular condyle and the articular space. The lateral teleradiogram studied by architectural and structural analysis provides information on the biomechanical balance of the cranio-facial structures and, especially, on the position of the mandibular rami. These standard radiograms are indispensable in the differential diagnosis, useful in the etiological diagnosis and are preliminary examinations prior to using other imaging techniques (MRI, CT). Standard films are easily reproducible for post-therapy follow-up.

[Pharmacologic therapy of cranio-cervico-mandibular disorders. Review of the literature]

The recommended treatments of craniomandibular disorders (CMD) are drug therapy, physiotherapy, relaxation procedures, occlusal therapy with and without splint. The purpose of this study is to carry out a survey of the literature on drug therapy in patients affected by CMD. It is essential to recognize the cause of pain (muscular or articular) and the phase of disorder (acute or chronic) in order to establish an adequate pharmacological protocol for each type of CMD. Non-steroidal anti-inflammatory drugs (NSAID) are generally accepted for treatment of internal derangement and myofacial pain, sometimes in association with benzodiazepine.

Occlusal splint therapy with a positioning orifice

The authors studied the effect of a positioning orifice introduced in the anterior palatine region of occlusal splints for patients with craniomandibular disorders of swallowing and speech patterns. The patients were evaluated in four distinct situations. It was concluded that the splint orifice significantly favored swallowing and speech while the splint was being used, and is more comfortable for the patient.

Short-term functional alterations in the stomatognathic system after orthodontic-surgical management of skeletal vertical excess problems

The aim of the present investigation was to study the functional alterations in the stomatognathic system following orthodontic-surgical management of skeletal vertical excess problems. The sample comprised 43 patients who received combined orthodontic-surgical treatment including bilateral vertical ramus osteotomy for posterior repositioning and counterclockwise rotation of the mandible (n = 26) or Le Fort I osteotomy for maxillary impaction (n = 17). All subjects were examined within 1 week before operation and 6 months postsurgery. Methods of examination included: (a) evaluation of dysfunction by means of a clinical index, (b) measurement of mandibular range of motion, (c) assessment of the number and intensity of occlusal contacts, and (d) tomographic evaluation of condyle-fossa relationships. The results of the study indicated that postoperatively (a) there was an increase of patients with dysfunction in the mandibular osteotomy group and a decrease of patients with dysfunction in the maxillary osteotomy group; (b) the maximum interincisal opening decreased significantly in the mandibular osteotomy group; (c) there was a significant increase in the number and intensity of occlusal contacts in both groups; and (d) the shortest posterior and anterior interarticular distances increased significantly in the mandibular osteotomy group.

Symptoms and signs of temporomandibular disorders in patients with fibromyalgia and local myalgia of the temporomandibular system. A comparative study

Symptoms and signs of temporomandibular disorders (TMD) in 46 patients were investigated and compared with those in 20 healthy individuals. Twenty-three patients had fibromyalgia (FM) and 23 had local myalgia (LM). Facial pain was assessed with a visual analogue scale, and a clinical examination was performed, including maximum voluntary mouth opening, temporomandibular joint sounds, tenderness to digital palpation in the masticatory muscles, pressure pain threshold and tolerance level of the superficial masseter muscle, intramuscular temperature, and maximum voluntary bite force. There was a difference in the number of tender muscles between the groups. Pressure pain threshold and tolerance levels were lower in the FM than in the LM group, whereas both showed lower values than a control group (C). The intramuscular temperature and maximum voluntary mouth opening were lower in the patient groups than in the C group. TMJ sounds showed a difference between all three groups. In conclusion, this study shows that FM patients frequently have TMD and indicates several differences between patients with FM and LM with regard to clinical variables.

Body position effects on sternocleidomastoid and masseter EMG pattern activity in patients undergoing occlusal splint therapy

This study was conducted in order to determine the effects of body position on electromyographic (EMG) activity of sternocleidomastoid and masseter muscles, in 15 patients with myogenic cranio-cervical-mandibular dysfunction undergoing occlusal splint therapy. EMG activity was recorded by placing surface electrodes on the sternocleidomastoid and masseter muscles (contralateral to the habitual sleeping side of each patient). EMG activity at rest and during swallowing of saliva and maximal voluntary clenching was recorded in the following body positions: standing, supine and lateral decubitus. In the sternocleidomastoid muscle significant higher EMG activities at rest and during swallowing were recorded in the lateral decubitus position, whereas during maximal voluntary clenching EMG activity did not change. In the masseter muscle significant higher EMG activity during maximal voluntary clenching in a standing position was observed, whereas EMG activity at rest and during swallowing did not change. The opposite pattern of EMG activity supports the idea that there may exist a differential modulation of the motor neuron pools of the sternocleidomastoid and masseter muscles, of peripheral and/or central origin. This suggests that the presence of parafunctional habits and body position could be closely correlated with the clinical symptomatology in these muscles in patients with myogenic craniomandibular dysfunction.

Subjective pain report and the outcome of several orthopaedic tests in craniomandibular disorder patients with recent pain complaints

A comparison between a subjective pain report and the outcome of the combined dynamic and static pain tests, and several other orthopaedic tests, was investigated in craniomandibular disorder (CMD) patients with recent pain complaints and in control subjects. Thirty-two CMD patients who clearly reported pain in the masticatory muscle region or in the temporomandibular joint region by means of a symptom report questionnaire (SRQ), participated in the study. The investigators performing the symptom report interview and the clinical tests were blinded to each other. A high correspondence was shown between the patients reporting joint or muscle pain (by means of SRQ) and the classification into arthrogenous and myogenous pain patients, based on the outcome of the dynamic and static pain tests (P = 0.0003). The outcome of four other orthopaedic tests: passive maximum mouth opening (PMMO; P = 0.0001), palpation of the temperomandibular joint (TMJ) and the masticatory muscles (P = 0.0002), TMJ-play (P = 0.0001), and TMJ-compression (P = 0.0138) demonstrated significant differences between the patients reporting joint and muscle pain.

Comparison of muscle activity and occlusal contacts during maximal and habitual clenching in varied chair positions

The activity of anterior temporal muscle, the number of tooth contacts, and total duration of closure during maximal and habitual clenching were studied in varied chair positions. Fifteen subjects were evaluated. The means for the muscle activity of anterior temporal muscle during habitual clenching were 63.5-73.5% of maximum muscle activity. The number of tooth contacts and total duration of closure were significantly increased as biting pressure was increased from habitual to maximal clenching. No significant differences were detected in all variables among varied chair positions. The above results also suggested that occlusal instability was very common. Further research is required to explain the relationship, if any, of these variables to craniomandibular disorders.

[Functional state of the masticatory system in healthy individuals (control group) and in patients with temporomandibular joint disorders]

The functional status of the masticatory system was investigated in a sample of 68 self-defined controls without any treatment need and 82 craniomandibular disorder patients. Among the parameters investigated were measures of mandibular mobility, the presence of joint noises and palpation tenderness of 17 muscle and 3 TMJ sites. These data allowed for calculation of Fricton's Craniomandibular Index (CMI) and Helkimo's Clinical Dysfunction Index (Di). Several socalled signs of dysfunction were found in the normal control group: 38% of the joints had some kind of noise and several muscle sites were tender to palpation (splenius capitis muscle 50%, anterior masseter and temporal muscle 45%, insertion of the trapezius muscle 40%). In addition, according to Helkimo's Di. 90% of the controls would be classified as having mild to moderate dysfunction. The high prevalence of positive signs in the control sample calls for a less rigid definition of what is called a normal craniomandibular status and refutes the a priori establishment of a narrow set of criteria for normality. Some parameters showed a highly statistically significant difference among the control and patient group (p < .001): active range of motion, deviation upon opening, pain on mandibular movement, number of tender palpation points and the CMI and Di.

Influence of complete denture renewal on craniomandibular disorders: a 1-year follow-up study

Great individual variation in the signs and symptoms of craniomandibular disorders (CMD) and in the adaptability of the masticatory system is evident among complete denture wearers. The masticatory system of 64 edentulous patients (41 women, 23 men; mean age 59 years, range 41-80 years), who came to the Institute of Dentistry for renewal of their complete dentures, was examined before prosthetic treatment and after a 1-year follow-up period. The degree of CMD was assessed using the anamnestic and clinical dysfunction indices of Helkimo. The results show that few complete denture wearers had severe signs and symptoms of CMD. No statistically significant correlation was noted between CMD and either the duration of edentulousness or the number of sets of dentures.

A clinical study of the relationship between occlusal curvature and craniomandibular disorders

The occlusal curvature should be harmonized with stomatognathic function, but excessive occlusal curvatures are found in some craniomandibular disorder patients. Forty healthy subjects and 95 patients with craniomandibular disorder (50 with clicking, 25 with locking, and 20 with myofascial pain dysfunction syndrome) were evaluated to investigate the functional significance of the occlusal curvature. Anteroposterior and lateral occlusal curvature were measured using the least-square approximation of the mandibular buccal cusps in a second-order quadratic and modification of Monson's 4-inch sphere. "Clicking" and "locking" groups had significantly greater occlusal curvatures than healthy subjects. There appeared to be a relationship between occlusal curvature and craniomandibular disorders.

Ten-year follow-up study of personality traits in adults with intact and restored dentitions

The personality traits of 69 of a sample of 70 adolescents aged 25-26 years were re-examined after 10 years by means of a personality inventory (KSP). A total of 11 subjects had intact dentitions (group I), while 18 subjects had had some fillings in their teeth since the first examination (group FI), and 40 subjects had restored dentitions from the starting-point (group F). The subjects with fillings 10 years ago had significantly higher scores in two of the anxiety variables--somatic anxiety and muscular tension--and in the hostility variable, suspicion, than did those without the fillings. Together with the finding of a significant correlation between high scores for the clinical dysfunction index (DiII and DiIII) and the muscular tension scale, the results of this study support the hypothesis of a possible correlation between dental filling therapy, craniomandibular disorders (CMD) and personality. Frequent tooth clenching (once to twice a week or more) was significantly more common among the subjects with fillings 10 years ago. The clenchers scored highest in the somatic anxiety, muscular tension and suspicion scales and constituted a well-defined subgroup within the subjects of this study. There was a highly significant increase of muscular tension among the clenchers during the 10-year examination period compared to the non-clenchers. However, the results of this study are not clear-cut. There was no statistically significant difference in personality between subjects with fillings after 10 years (group F + Fi) and the group of subjects with intact teeth (group I). Hypothetically, this may indicate that the differences found in this study could be due to how long the fillings had been in the mouth and at which age they were inserted. In order to test the hypothesis further and to establish the possible mechanisms behind this finding, more studies are necessary and especially more longitudinal comparative studies between subjects with intact and restored dentitions.