Biomedical subjects

A Michelotti

Publications and source records attributed to A Michelotti.

At least 19 recordsLinked to original sources

PubMed2006

No effect of experimental occlusal interferences on pressure pain thresholds of the masseter and temporalis muscles in healthy women.

It has been suggested that occlusal interferences may lead to pain and tenderness of the masticatory muscles. Tender jaw muscles are more sensitive to pressure pain, as assessed by means of pressure algometry. We tested the effects of occlusal interferences on the pressure pain threshold of the jaw muscles by means of a double-blind randomized crossover experiment carried out on 11 young healthy females. Golden strips were glued either to an occlusal contact area (active interference) or to the vestibular surface of the same tooth (dummy interference) and left for 8 d each. Pressure pain thresholds of the masseter and anterior temporalis muscles were assessed under interference-free, dummy-interference and active-interference conditions. The results indicated that the application of an active occlusal interference, as used in this study, did not influence significantly the pressure pain thresholds of these muscles in healthy individuals.

Adult↗

PubMed2005

Home-exercise regimes for the management of non-specific temporomandibular disorders.

There is a consensus on treatment strategies for temporomandibular disorders (TMDs) being reversible. Among reversible therapies, physiotherapy is often chosen for the treatment of TMD pain and dysfunction because it is simple and non-invasive, it has a low cost as compared with other treatments, it allows an easy self-management approach, it allows a good doctor-patient communication, and it can be managed by the general practitioner. Home-exercises regime protocols are reviewed in this article in the context of the biopsychosocial approach. The actual evidence for the efficacy of home physical exercises is weak because of the very limited number of randomized clinical trials (RCTs) available in literature. Therefore, there is a need for further well-designed studies and RCTs to investigate the therapeutic efficacy. Recent reports and clinical experience, however, suggest that this approach can be promising, particularly if it is tailored towards the individual patient. The favourable cost benefit ratio over other treatment modalities seems to indicate that physiotherapy can be regarded as a first choice approach in selected TMD patients.

Cost-Benefit Analysis↗

PubMed2005

The relationship between vertical craniofacial morphology and the sagittal path of mandibular movements.

The aim was to investigate the relationship between the vertical craniofacial morphology and the sagittal path of mandibular movements. The study was carried out in 40 subjects who were free of temporo-mandibular disorders. Mandibular movements and maximal jaw opening (MO) were recorded by means of a jaw tracking device. The opening-closing angle (OCA) was defined as the angle between the horizontal plane and the opening-closing path of movements. Vertical craniofacial morphology was assessed on prophile cephalograms by means of the Frankfort Mandibular Plane Angle (MP). The OCA did not differ between males and females (P>0.05). OCA and MP were negatively correlated (r=-0.62; P<0.001). MO was significantly greater in males that in females (P<0.05). MO was negatively correlated to MP (-0.44<r<-0.49; P<0.05). The findings suggest that the low-angle subjects exhibit a more vertical path of the mandibular movements than that of high-angle subjects. Differences in the sagittal path of jaw movements may be partly ascribed to anatomical factors.

Adult↗

PubMed2005

Effect of occlusal interference on habitual activity of human masseter.

It has been suggested that occlusal interference may increase habitual activity in the jaw muscles and may lead to temporomandibular disorders (TMD). We tested these hypotheses by means of a double-blind randomized crossover experiment carried out on 11 young healthy females. Strips of gold foil were glued either on a selected occlusal contact area (active interference) or on the vestibular surface of the same tooth (dummy interference) and left for 8 days each. Electromyographic masseter activity was recorded in the natural environment by portable recorders under interference-free, dummy-interference, and active-interference conditions. The active occlusal interference caused a significant reduction in the number of activity periods per hour and in their mean amplitude. The EMG activity did not change significantly during the dummy-interference condition. None of the subjects developed signs and/or symptoms of TMD throughout the whole study, and most of them adapted fairly well to the occlusal disturbance.

Adaptation, Physiological↗

PubMed2001

Identification of the highest dose of docetaxel associable with active doses of epirubicin. Results from a dose-finding study in advanced breast cancer patients.

PURPOSE: To determine the maximum tolerated dose (MTD) and the dose limiting toxicity (DLT) of docetaxel in combination with fixed doses of epirubicin. PATIENTS AND METHODS: Women with locally advanced or metastatic breast cancer were given docetaxel, 60 mg/m2 in escalated doses by steps of 10 mg/m2, in association with two fixed doses of epirubicin (90 mg/m2, and 75 mg/m2). Since neutropenia was foreseen to be the most likely DLT, a third group with prophylactic G-CSF support was planned to define the MTD of docetaxel with 90 mg/m2 of epirubicin. Selected patients underwent pharmacokinetic evaluation of docetaxel. RESULTS: Fifty-eight patients entered the study. At the first step (90 mg/m2 of epirubicin) the MTD was obtained at 60 mg/m2 of docetaxel. At the second step (75 mg/m2 of epirubicin) the MTD of docetaxel was 80 mg/m2. At the third step (epirubicin 90 mg/m2) G-CSF allowed a safe escalation of docetaxel up to 90 mg/m2. Neutropenia was the most common hematological adverse event. Without G-CSF, grade 4 neutropenia occurred in 69% of cycles, of which 11% was complicated by fever. In G-CSF group, grade 4 neutropenia and neutropenic fever occurred in 31% and 3%, respectively. Most frequent non-hematological adverse effects were asthenia (45%), nausea (39%) and mucositis (36%). No patient developed congestive heart failure. Two toxic deaths occurred. Overall response rate was 73% in 42 out of 58 patients, with no apparent epirubicin dose-related effect. No statistically significant effect of the two doses of epirubicin was observed in docetaxel pharmacokinetics. CONCLUSIONS: On the basis of the toxicity profile, the docetaxel pharmacokinetics and the response rate observed, epirubicin 75 mg/m2 combined with docetaxel 80 mg/m2 can be recommended for further studies.

Adult↗

PubMed2001

Effects of prolonged gum chewing on pain and fatigue in human jaw muscles.

Gum chewing has been accepted as an adjunct to oral hygiene, as salivary stimulant and vehicle for various agents, as well as for jaw muscle training. The aim of this study was to investigate the effects of prolonged gum chewing on pain, fatigue and pressure tenderness of the masticatory muscles. Fifteen women without temporomandibular disorders (TMD) were requested to perform one of the following chewing tasks in three separate sessions: chewing a very hard gum, chewing a soft gum, and empty-chewing with no bolus. Unilateral chewing of gum or empty chewing was performed for 40 min at a constant rate of 80 cycles/min. In each session, perceived muscle pain and masticatory fatigue were rated on visual analog scales (VAS) before, throughout, and after the chewing task. Pressure pain thresholds (PPTs) of masseter and anterior temporalis muscles were assessed before and immediately after the chewing tasks, and again after 24 h. The VAS scores for pain and fatigue significantly increased only during the hard gum chewing, and after 10 min of recovery VAS scores had decreased again, almost to their baseline values. No significant changes were found for PPTs either after hard or soft gum chewing. The findings indicate that the jaw muscles recover quickly from prolonged chewing activity in subjects without TMD.

Adult↗

PubMed2000

Single agent epirubicin as first line chemotherapy for metastatic breast cancer patients.

In order to better explore the toxicity and the activity of high dose epirubicin (120 mg/m2, 3 weeks) we analyzed a population of 127 metastatic breast cancer patients, treated in a randomized clinical trial conducted to evaluate the cardioprotective effect of dexrazoxane against epirubicin induced cardiotoxicity. All the patients had a diagnosis of metastatic breast cancer, an ECOG performance status < or = 2 and normal hematologic, renal, hepatic and cardiac function. No prior adjuvant chemotherapy including anthracycline was allowed. Epirubicin was given at the dose of 120 mg/m2 i.v. bolus every 3 weeks. One hundred twenty five patients were evaluable for toxicity and response. Seventeen patients (11%) had a complete response and 47 patients (37%) a partial response, for an overall response rate of 48%. The median progression free and overall survivals were 8.3 months and 18.3 months, respectively. Grade 3 and 4 leukopenia were observed in 8% and 7% of the patients, respectively. The most frequent nonhematological grade 3 toxicities were alopecia (87%), nausea and vomiting (16%), and mucositis (8%). Cardiotoxicity, defined as occurrence of congestive heart failure, decrease in resting left ventricular ejection fraction (L-VEF) to < or = 45%, or 20 EF units decrease from baseline L-VEF, was observed in 19% of the patients, after a median cumulative dose of epirubicin of 720 mg/m2 (range 120-1440). This study confirms in a large series of patients the activity of high dose epirubicin; however, the high incidence of cardiotoxicity requires a careful evaluation of cardiac risk factors before treatment.

Adult↗

PubMed2000

The diagnostic value of pressure algometry in myofascial pain of the jaw muscles.

Recent evidence suggests that evaluation of muscle tenderness in temporomandibular disorders (TMDs) patients might be improved by the use of pressure algometry; nevertheless, the evaluation of the diagnostic value of this tool has received little attention. The aim of this study was to assess the diagnostic value of pressure algometry in myofascial pain of the jaw muscles, by calculation of sensitivity (Se), specificity (Sp) and positive predictive values (PPV). Pressure pain thresholds (PPTs) of masseter and anterior temporalis muscles were assessed in 40 female myogenous TMD patients and 40 age-matched female controls. PPTs were significantly lower (P<0.001) in TMD patients than in control subjects for both masseter and temporalis muscles, being 40-50% of the control values. Setting a cutoff value 1 s.d. below the mean PPT values of control subject, sensitivity and specificity were 0.67 and 0.85, respectively, for the masseter muscle and 0.77 and 0.87, respectively, for the temporalis muscle. When taking into account the prevalences of myofascial pain in the general population and in TMD clinics, the PPV ranged from 0.5 to 0.7. As a result of the low PPV, pressure algometry has strong limitations when used as a solitary diagnostic tool.

Adult↗

PubMed2000

Does the ovarian cycle influence the pressure-pain threshold of the masticatory muscles in symptom-free women?

AIMS: To test the hypothesis that the ovarian cycle influences the pressure-pain threshold of the masticatory muscles. METHODS: Eighteen healthy women with a regular menstrual cycle (28 +/- 2 days), ranging in age from 18 to 35 years, participated in the study. For each subject, pressure-pain thresholds (PPTs) of the masseter and temporalis muscles were assessed at 4 muscular sites by means of an electronic algometer. Measurements were taken at 4 separate sessions across the menstrual cycle corresponding to the following phases: menstrual, follicular, periovulatory, and luteal. Menstrual cycle phases were determined by a pelvic ultrasonographic screening. The study was carried out in a single-blind design, and the initial session was randomly determined for each individual. Data collected were analyzed by repeated-measures analysis of variance. RESULTS: The findings suggest that the PPTs of several masticatory muscles (2 of 4) are influenced by the ovarian cycle, but to a minor extent (P < 0.05), and the influence is of limited clinical relevance. CONCLUSION: In healthy subjects, there is a link between mechanical sensitivity of the masticatory muscles and fluctuation of the ovarian hormones. The relationship between PPTs of the masticatory muscles and the ovarian cycle should be also investigated in patients with temporomandibular disorders and/or orofacial pain conditions.

Adolescent↗

PubMed2000

Changes in pressure-pain thresholds of the jaw muscles during a natural stressful condition in a group of symptom-free subjects.

AIMS: To investigate the effects of a natural emotional stressor on pressure-pain thresholds (PPTs) of the masticatory muscles of symptom-free subjects. METHODS: Sixteen healthy dental students were selected before they undertook an academic examination. Sixteen gender-matched students who were not exposed to an examination served as controls. The 2 groups of students were monitored in parallel on 5 separate days over a 1-month period: 2 days before the examination (T1), on the day of the examination (T2), 2 days after (T3), 1 month after (T4), and again after another 2 days (T5). On the day of the examination (T2), the control students were only required to complete a brief, non-demanding questionnaire. On each day, the following parameters were assessed: PPTs of the masseter, the anterior temporalis, and the Achilles tendon; state anxiety; and present stress (measured on a visual analog scale [VAS]). Furthermore, in the students undergoing the examination, venous blood samples for assessment of beta-endorphin levels were obtained at T2 and T5. RESULTS: In the stressed students, the PPTs of the masticatory muscles and the Achilles tendon were significantly lower (analysis of variance [ANOVA], P < or = 0.02) on the day of the examination (T2) and on the days nearest the exam (T1, T3), and state anxiety and present stress were significantly higher (ANOVA, P < or = 0.003). No significant change was found in beta-endorphin plasma levels (P > 0.05). In the control group, PPTs, state anxiety, and present stress did not change significantly (ANOVA, P > 0.05). CONCLUSION: The results support a relationship between psychologic stress and pressure-pain sensitivity of the masticatory muscles.

Achilles Tendon↗

PubMed1999

Cardiovascular responses in humans to experimental chewing of gums of different consistencies.

Although the cardiovascular effects of exercise have been extensively investigated in man, little attention has been paid to such responses to jaw muscle activity. The aim here was to investigate the general cardiovascular effects of chewing activity in a single-blind, cross-over design. Ten healthy individuals performed one of the following chewing tasks in four separate sessions: chewing a very hard gum, chewing a moderately hard gum, chewing a soft gum, and "empty chewing" without a bolus. Unilateral chewing of gum or empty chewing was performed for 20 min on the participant's most convenient chewing side at a constant rate of 80 cycles/min. In each session, heart rate and arterial blood pressure were recorded together with electromyographic activity in the masseter and anterior temporalis muscles on the chewing side. Ratings of perceived masticatory fatigue were recorded with visual analogue scales. The heart rate and blood pressure were significantly increased (ANOVA; p < or= 0.01) during the chewing tasks and the increases were, in parallel with the muscle activity, more pronounced the harder the gum. With the very hard gum, heart rate increased by up to 11 beats/min, the systolic blood pressure was 14 mmHg (1.9kPa) higher, and the diastolic blood pressure was 11 mmHg (1.5kPa) higher. The perceived fatigue was proportional to the level of muscle activity. After 10 min of recovery from exercise, heart rate and arterial blood pressures were slightly but still significantly elevated. The results demonstrate that chewing is associated with general circulatory effects proportional to the bolus resistance.

Adult↗

PubMed1999

Sensory and motor changes of the human jaw muscles during induced orthodontic pain.

The aim of this study was to evaluate the short-term effects of orthodontic pain on the pressure pain threshold (PPT) of the masseter and anterior temporalis muscles, and on their electromyographic (EMG) activity during clenching and chewing. Orthodontic pain was induced in 14 healthy subjects (mean age 26.6, SEM 1.1) by placing orthodontic separators. The subjects were randomly assigned to an experimental and to a control session in a double-blind crossover study. PPT was significantly reduced (Student's t-test; P < 0.001) after experimental sessions for both the masseter and the anterior temporalis muscles, whereas no significant differences were found during control sessions (P > 0.05). EMG activity during clenching and chewing was significantly reduced (0.001 < or = P < 0.05) after experimental sessions for both masseter and anterior temporalis muscles, whereas no significant differences were found during control sessions (P > 0.05). The decrease of PPT found in this study can be related to the occurrence of muscle pain and headache reported by patients during orthodontic or other dental treatment. The decrease of EMG activity of the jaw muscles associated with orthodontic pain is consistent with the pain adaptation model and should be considered as a potential factor for loss of occlusal anchorage during orthodontic treatment.

Adult↗

PubMed1999

[Occlusion and posture: is there evidence of correlation?].

The observation that the masticatory system and the postural body regulating system are anatomically and functionally related, has led to postulate several hypotheses of correlation between occlusal and postural disturbances. In the last decade, these arguments have gained a great social impact, also because they have been broadly spread by the mass-media. As a consequence, there has been a growing number of patients seeking concomitant occlusal and postural treatments. The aim of this study was to review critically the current evidence of correlation between the two systems; this in order to address clinical issues for the management of patients. Methodology of the studies reviewed has been evaluated according to the criteria suggested by Storey and Rugh 20 rif. Although there are some evidences of correlation between occlusion and posture, this appears limited to the cranio-cervical tract of the column and tends to disappear when descending in cranio-caudal direction. On the basis of this review of the literature, it's not advisable to treat postural imbalance by means of occlusal treatment or vice versa, particularly if the therapeutic modalities are irreversible.

Clinical Trials as Topic↗

PubMed1998

Personality characteristics of temporomandibular disorder patients using M.M.P.I.

It is generally recognized that psychological factors play an important role in chronic orofacial pain patients. This study analysed psychological profiles of chronic pain patients affected with temporomandibular disorders (TMD), by means of the Minnesota Multiphasic Personality Inventory (MMPI) test. Fifty consecutive TMD patients were examined and were then divided into two subgroups: 1. myofascial pain and 2. temporomandibular joint articular disorders. Sixty-two percent of the whole sample presented pathological MMPI scores. Both subgroups presented similar profiles with alteration of the neurotic triad (hypochondriasis, depression, hysteria), and pathological values of hypochondriasis and hysteria ("V" configuration). Since the personality profile did not differ between the two subgroups investigated, it was not dependent on the dysfunctional origin of the pathology (myalgia or primary TMJ pathology). Chronic TMD patients presented personality characteristics similar to those of other chronic pain patients according to the MMPI.

Adolescent↗

PubMed1998

Comparison of clinical and psychologic features of fibromyalgia and masticatory myofascial pain.

The aim of this study was to investigate common symptoms and divergent features in fibromyalgia (FS) and masticatory myofascial pain (MFP) in patients affected by craniomandibular disorders. Twenty-three women with MFP and 23 women with FS were studied. All patients were examined by a dentist and by a rheumatologist. Craniomandibular disorders were assessed with a subjective symptoms questionnaire, detailed history interview, joint function examination, and manual palpation of masticatory and cervical muscles. The Middlesex Hospital Questionnaire was used to obtain personality profiles of the patients. The craniomandibular disorders questionnaire revealed various similarities in the two groups, the most striking of which were pain during mandibular function, articular noises, and headache. Both groups had muscle pain upon palpation; the mean scores (on a 0 to 4 scale) did not differ significantly between the two groups and ranged between 1.39 (SD 1.2) and 2.86 (SD 0.75). The mean value of active mouth opening was 40.9 mm (SD 9.1) in MFP patients and 44.6 mm (SD 7.2) in FS patients, while the mean value of passive opening was 49.6 mm (SD 6.0) in MFP patients and 49.8 mm (SD 3.5) in FS patients. These values did not differ significantly between the two groups, but did differ from the normal population, similar to the trend of the psychologic profile. The authors conclude that the physician should be alert to the need to conduct interdisciplinary evaluations in the diagnosis and management of FS and of MFP.

Adolescent↗

PubMed1997

Mandibular rest position and electrical activity of the masticatory muscles.

STATEMENT OF PROBLEM: The determination of a correct vertical dimension of occlusion is a critical procedure in clinical dentistry. PURPOSE: The objectives of this study were to analyze the relation between mandibular rest position and electrical activity of masticatory muscles and to compare clinical and electromyographic rest position in subjects with different vertical facial morphologic features. MATERIAL AND METHODS: Clinical rest position and electromyographic rest position were investigated in 40 subjects. Electromyographic rest position ranged from 0.4 to 12.7 mm (average 7.7 +/- 2.7 mm). Clinical rest position ranged from 0.1 to 4.4 mm (average 1.4 +/- 1.1 mm). The average difference between electromyographic rest position and clinical rest position was 6.3 +/- 2.5 mm (range 0.3 to 10.3 mm). Sixteen subjects were selected according to the Frankfort mandibular plane angle and separated in two groups having a mandibular plane angle > or = 28 degrees. RESULTS: Rest position was significantly greater (p < 0.05) in the low-angle group (2 +/- 1.3 mm) than in the high angle group (0.8 +/- 0.8 mm). Electromyographic rest position did not differ between subjects with different facial morphologic features (8.1 +/- 1.7 mm low-angle group; 7.6 +/- 4.1 mm high angle group). By varying the vertical dimension millimeter by millimeter, masseter and anterior temporal electromyographic activity demonstrated a considerable decrease over an interocclusal distance of 3 to 4 mm. Further mandibular opening up to 18 mm corresponded to small changes in postural activity. CONCLUSION: This study suggests that a jaw posture with a few millimeters of interocclusal distance involves a great reduction of masticatory muscle activity.

Adult↗

PubMed1997

Dose-finding study and pharmacokinetics of epirubicin and paclitaxel over 3 hours: a regimen with high activity and low cardiotoxicity in advanced breast cancer.

PURPOSE: To determine the maximum-tolerated dose (MTD) of paclitaxel over 3 hours with a fixed dose of epirubicin, to investigate the plasma pharmacokinetics of this combination, and to evaluate the toxicity and the activity in previously untreated metastatic breast cancer patients. PATIENTS AND METHODS: Fifty patients with metastatic breast cancer, measurable disease, and normal left ventricular ejection fraction (LVEF) were eligible. Epirubicin was administered as an intravenous (I.V.) bolus at the fixed dose of 90 mg/m2 before the infusion of paclitaxel over 3 hours. The initial dose of paclitaxel was 135 mg/m2 and was increased by 20 mg/m2 in subsequent cohorts of six patients until dose-limiting toxicity (DLT). Plasma pharmacokinetics of paclitaxel and epirubicin was performed at cycle 1 in at least two patients per dose level of paclitaxel (175 up to 225 mg/m2). RESULTS: The DLT of this combination was febrile neutropenia in two of eight patients who received paclitaxel at 225 mg/m2. The mean peak plasma concentration of paclitaxel ranged between 5.1 and 6.2 micromol/L at doses of 175 to 225 mg/m2. The concentration of epirubicinol decreased from 47.3 +/- 9.4 to 37.9 +/- 7.5 ng/mL in patients treated with paclitaxel 175 and 225 mg/m2. The most relevant toxicity was grade 4 neutropenia (61% of all courses). The pharmacokinetic data of paclitaxel, in particular the time above the threshold level of 0.05 micromol/L, were not significantly related to myelosuppression. Cardiac toxicity was mild: three patients (6%) developed mild congestive heart failure that was responsive to therapy. Among 49 assessable patients, 41 responses (84%; 95% confidence interval [CI], 70% to 92%) were observed, and nine (18%) of these were complete. CONCLUSION: Our study demonstrates that (1) the MTD is epirubicin 90 mg/m2 and paclitaxel 200 mg/m2; (2) no clear relationship exists between pharmacokinetic data of paclitaxel and myelosuppression, while the increase in the dose of paclitaxel is associated with a reduction in epirubicinol plasma levels; and (3) the association is feasible, with low cardiotoxicity, and has a high activity in metastatic breast cancer.

Adult↗

PubMed1996

Paclitaxel and vinorelbine in anthracycline-pretreated breast cancer: a phase II study.

BACKGROUND: Paclitaxel and vinorelbine are active in advanced breast cancer pretreated with anthracyclines We therefore conducted a phase II study to define the toxicity and activity of paclitaxel and vinorelbine administered in combination. PATIENTS AND METHODS: Our patient population consisted of 37 patients with metastatic breast cancer, 35 of whom had received prior chemotherapy including anthracyclines. The treatment regimen included vinorelbine (25 mg/m2 i.v.) followed by paclitaxel (135 mg/m2 i.v. as a 3-hour infusion) on day 1; vinorelbine was repeated on day 8 in the first 14 patients and on day 3 in the remaining 23 patients. RESULTS: Because of grade 4 neutropenia, the second dose of vinorelbine was reduced or omitted in 88% of the courses on the days 1 and 8 schedule and in 48% of the courses on the days 1 and 3 schedule. As a consequence the administered dose intensity of vinorelbine was significantly higher on the days 1 and 3 schedule (13 mg/m2/wk versus 8.3 mg/m2/ wk, P = 0.005). The overall response rate was 38% (95% CI: 22-55); four responses have been observed in the ten patients with absolute anthracycline resistance. The median duration of response was 6.5 months. CONCLUSIONS: The combination of paclitaxel and vinorelbine is a feasible and active salvage regimen in advanced breast cancer patients pretreated with anthracyclines.

Adult↗