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Biomedical subjects

S Palla

Publications and source records attributed to S Palla.

At least 19 recordsLinked to original sources
PubMed2002

[Burning mouth].

BACKGROUND: The complaint of burning mouth is fairly common. Epidemiological studies suggest a prevalence of around 15% in postmenopausal women and between 0,7 and 7,9% for the general population. PURPOSE: The purpose of this article is to present a review of the literature on epidemiology, clinical symptoms, etiology, diagnosis, treatment and prognosis of burning mouth and burning mouth syndrome. RESULTS AND CONCLUSIONS: Potential causal factors have been extensively studied and reviewed, suggesting a multifactorial aetiology, that apparently includes local, systemic and psychogenic factors. However, reports of their relative importance are conflicting. Consequently this lack of evidence is reflected in inconsistent guidelines for diagnosis and treatment. Most of the authors emphasize the importance of history taking and clinical intraoral examination for diagnosis. The symptom of burning mouth associated with clinical mucosal abnormality has to be differentiated from burning mouth syndrome (BMS), a condition in which no mucosal abnormality is evident on examination. Whereas the symptom of burning mouth associated with clinical mucosal signs is described to be often manageable by eliminating possible causal factors, the background of most of the proposed treatments for BMS is empiric or even purely anecdotal. Only a few randomised controlled studies have been performed on treatment outcome. Their differing results are presented in a short overview.

Burning Mouth Syndrome↗
PubMed2002

[Principles on therapy of myoarthropathic pain].

The myoarthropathic pain is the major source of orofacial pain. The 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 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 in presence of pain on awakening, ostheoarthritis, a painful discopathy, and/or a malocclusion caused by condylar remodeling secondary to ostheoarthrosis. Only in a small percentage of patients the myoarthropathic pain persists and becomes chronic. These patients 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 behavioral pain component and be tailored to the single patient based on his/her psychosocial and constitutional characteristics. The goal is not pain relieve but improvement of the quality of life by teaching the patient more efficient pain coping strategies by means of behavioral and relaxation therapy. 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.

Affect↗
PubMed2001

Regulation of mandibular postures: mechanisms and clinical implications.

This review argues that (1) the habitual mandibular position is constantly variable and so cannot be considered as a craniomandibular reference point, (2) there is no unique centric relation, (3) mandibular posture greatly depends on head posture, (4) clinical evaluation of the occlusal vertical dimension is mostly empirical, and (5) neither the vertical dimension at rest nor the centric relation can be determined by means of existing instrument-based clinical methods. However, some physiological conditions exist that facilitate the recording of craniomandibular position.

Centric Relation↗
PubMed2000

Mandibular helical axis pathways during mastication.

Condylar and incisor trajectories are often used for the study of mandibular movements. Condylar trajectories, however, depend on the location of the reference point and can be interpreted erroneously. In contrast, the helical axis analysis yields an unequivocal description of rigid body kinematics. The aim of this study was to analyze the mandibular helical axis during mastication. Seven subjects without signs and symptoms of craniomandibular disorders and with class I occlusion were recorded by means of the opto-electronic system Jaws-3D during unilateral mastication of bread cubes (2-cm side). The helical axis was computed every 14 ms with a rotation threshold of 1 . Parameters describing its spatial orientation and position relative to the condyles were calculated. The helical axis changed orientation and position more pronouncedly during the closing than during the opening phases of mastication. The orientation varied significantly from beginning to end of closing but not of opening, indicating less fluctuation of the helical axis on opening than on closing. Also, the distance dCP between helical axis and reference condylar point varied more significantly (p < 0.05) on the working than on the balancing side: On the working side, dCP decreased during both opening and closing, whereas on the balancing side, dCP increased only for closing. Furthermore, the helical axis pathway often showed a bowing ventrally to the balancing condyle, indicating that, during closing, the balancing condyle still translated backward while essentially only rotation occurred around the working condyle. Thus, the helical axis changed its position and orientation continuously during mastication.

Adult↗
PubMed2000

Stress-field translation in the healthy human temporomandibular joint.

Movement over the surface of the temporomandibular joint (TMJ) disc produces tractional forces. These forces potentially increase the magnitude of shear stresses and contribute to wear and fatigue of the disc. Theoretically, tractional forces in all synovial joints are the result of frictional forces, due to rubbing of the cartilage surfaces, and plowing forces, due to translation of the stress-field through the cartilage matrix as the joint surface congruency changes during motion. For plowing forces to occur in the TMJ, there must be mediolateral translation of the stress-field as the condyle moves dorsoventrally during jaw function. To test whether mediolateral stress-field translation occurs in the intact TMJ, we measured stress-field position and translation velocities in ten normal individuals during rhythmic jaw opening and closing. Magnetic resonance imaging and jaw tracking were combined to animate the three-dimensional position of the stress-field between the articulating surfaces. This allowed for mediolateral translation velocity measurements of the centroid of the stress-field. The results showed that during jaw opening and closing at 0.5 Hz, the average peak mediolateral translation velocity was 35 +/- 17 mm/sec. When opening and closing increased to 1.0 Hz, the average peak velocity was 40 +/- 19 mm/sec. Theoretical model estimates of the work done during such translation ranged from 6 to 709 mJ between the individual joints studied. The potential clinical importance of this measure is that long-term exposure of the TMJ disc to high work may result in fatigue failure of the TMJ disc.

Adult↗
PubMed2000

Dynamic magnetic resonance imaging technique for the study of the temporomandibular joint.

AIMS: Echo planar imaging (EPI) is an ultrafast magnetic resonance imaging (MRI) technique that can scan a single frame in less than a second. The aim of this study was to use the EPI technique to develop a new dynamic MRI protocol for the temporomandibular joint (TMJ). METHODS: Basic fast-field echo and EPI pulse sequences were used for dynamic studies of the TMJ. The subjects were instructed to perform spontaneous, continuous, slow opening/closing movements without visual or audio feedback. Different scanning parameter settings were explored to optimize the results. RESULTS: With an opening/closing movement of approximately 6 to 7 seconds per cycle, the proposed protocol yielded a good insight into the relative motion between condyle and disc. It was also possible to see the deformation of the disc during movement. CONCLUSION: The EPI technique is a non-invasive technique that can be used for dynamic imaging study of a slow but continuous, uninterrupted jaw movement.

Adult↗
PubMed2000

Individualized oblique-axial magnetic resonance imaging for improved visualization of mediolateral TMJ disc displacement.

AIMS: A new individualized oblique-axial orientation of magnetic resonance imaging scans of the temporomandibular joint (TMJ), corrected to be perpendicular to the tangent of the posterior slope of the articular eminence, has been proposed to improve the representation of the disc. The aim of this study was to evaluate the quality of the images obtained with this new type of scanning plane and to assess the factors that can affect the scans. METHODS: Twenty-nine TMJs were scanned by the use of sagittal, conventional coronal, and individualized oblique-axial scanning planes. On the sagittal images, the angle alpha between the tangent of the posterior slope of the articular eminence and the vertical was measured, and the disc position was evaluated. For both imaging planes, 2 examiners, blind to the scanning techniques, counted the number of conventional coronal and oblique-axial scans in which the disc was visible and in which the medial and lateral disc borders were well demarcated and evaluated the mediolateral disc position. RESULTS: The individualized oblique-axial technique was superior to the conventional coronal technique in depicting the disc and its medial and lateral demarcations (paired t test, P < 0.05). The possibility of correct diagnosis of the mediolateral disc position and the agreement between the observers in this evaluation were better with the oblique-axial technique than with the conventional technique (P < 0.05). This was particularly evident when the disc was anteriorly displaced. CONCLUSION: The individualized oblique-axial scanning planes should be used for a better representation of the disc/condyle complex mediolaterally if the disc is anteriorly displaced.

Adolescent↗
PubMed2000

Reproducibility of temporomandibular joint clicking.

AIMS: To investigate the stability of temporomandibular joint (TMJ) clicking over a 10-day period and the effect of different open/close velocities on sound amplitude and power spectra in a group of subjects with subjectively stable unilateral clicking during the 3 months preceding the recordings. METHODS: Ten volunteers were recorded with a self-developed microcomputer-based system used in a previous study on asymptomatic subjects. The recordings were performed during 4 different sessions at 3 different open/close rates in each session. The subjective sound intensity was measured with a 100-mm visual analog scale (VAS). The VAS scores, the maximum amplitudes, and the power spectra of the signals were tested for statistical differences among the different open/close rates and over the sessions. The reliability of measurements was also calculated. RESULTS: The maximum amplitude and the power spectra of the TMJ clicking varied between subjects in a broad range that differed from those reported for asymptomatic subjects. No statistically significant differences were found within subjects for the subjective VAS scores for the maximum signal amplitudes or for the power spectrum parameters among the open/close rates and over the 4 sessions. For all 3 open/close rates and for the 4 sessions, a good to excellent reliability of measurements was determined, the values of r being mostly over 0.75. CONCLUSION: Within the limits of the experiment, TMJ clicking was subjectively and objectively stable over a period of 10 days. Therefore, the constant subjective perception of sound intensity was supported by the objective measurements.

Adult↗
PubMed1999

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.

Adult↗
PubMed1998

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.

Adolescent↗
PubMed1997

Reliability of scoring EMG orofacial events: polysomnography compared with ambulatory recordings.

The study of sleep bruxism is usually based on clinical history, signs and symptoms. The recording of electromyographic signals with either ambulatory portable home recorders or with polysomnographic techniques in the laboratory environment allows collection of objective data. The present study showed a 100% agreement with clinical evaluation in the recognition of bruxism episodes from the masseter electromyogram recorded with portable recorders and using the polysomnographic technique. On the contrary, scorers had difficulties in discriminating between different types of episodes (phasic, tonic and mixed), the between-scorers agreement varied between 62% and 63% and the kappa-values between 0.43 and 0.33. The ideal time base at which electromyographic signals should be integrated to allow for a good discrimination of bruxism patterns is 0.06 s. The results indicate that portable electromyography recorders are a valuable complement to polysomnographic recordings of orofacial motor activities as they provide a very good recognition rate with adequate time base data collection.

Adult↗
PubMed1997

The functional status of the masticatory system of 11-16-year-old adolescents: classification and validity.

Epidemiological studies to assess the prevalence and course of functional disturbances of the masticatory system should be based on a valid and reliable measure of the functional status of the masticatory system. NIELSEN et al. (2, 3) proposed a classification method that included three different classes of dysfunction. This classification was used to compare the results of a sample of 447 11-16-year-old Swiss adolescents with those of the Danish study and to test the validity of this classification method. The two studies showed similar prevalences in two of the three dysfunction classes and a similar pattern of dysfunction categories. Concurrent and construct validity analyses showed significant correlations between the assessment from clinical examination and the subjective judgments of the adolescents. The results demonstrated cross- and concurrent validation of the "Nielsen index" but also stressed the necessity of a careful re-evaluation of the "severe" class criterion. The limitations of the Nielsen index led to the construction of a "Zurich-MAP index". The potential applications of both indices are discussed.

Adolescent↗
PubMed1997

Description of mandibular finite helical axis pathways in asymptomatic subjects.

Despite wide use of systems to record jaw motion with six degrees of freedom, most studies have analyzed only the movement of a single mandibular point. The finite helical axis (FHA) is a mathematical model which can be used to describe comprehensively the movements of a rigid body. The aim of this investigation was to describe the FHA of the mandible during habitual jaw movements. Thirty subjects (13 females, 17 males; mean age, 26 years; range, 18 to 34 years) without myoarthropathies of the masticatory system participated in the study. Opening and closing movements, performed at 1-Hz frequency, were recorded with the optoelectronic system Jaws-3D. Three opening and closing movements were recorded from the right side and three from the left side of the jaw. The movement data were low-pass-filtered for noise reduction prior to the computation of the finite helical axis by means of a software program developed in our laboratory. The following parameters were calculated: the rotation of the FHA, its spatial orientation, and the translation along it, as well as its position and distance relative to an intracondylar point. In addition, methodological errors of the model were calculated. During opening and closing, the group mean FHA rotation was 24.3 degrees +/- 4.2 degrees. The group mean of the maximum total translation along the FHA was 0.9 +/- 0.7 mm. The group mean distance between the FHA and the intracondylar point was 48.9 +/- 9.9 mm. The FHA pathways were smooth and varied between individuals. Furthermore, the finite helical axes were never localized within the condyle, and often were located outside of the mandible. The analysis of the FHA pathways yields more information on whole mandibular movements than simply the movements of a single condylar point.

Adolescent↗