TMD before and after correction of dentofacial deformities by orthodontic and orthognathic treatment.

The aims of the study were to investigate the alteration of temporomandibular disorders (TMD) after correction of dentofacial deformities by orthodontic treatment in conjunction with orthognathic surgery; and to compare the frequency of TMD in patients with dentofacial deformities with an age and gender matched control group. TMD were evaluated in 121 consecutive patients (treatment group), referred for orthognathic surgery, by a questionnaire and a clinical examination. 18 months after treatment, 81% of the patients completed a follow-up examination. The control group comprised 56 age and gender matched subjects, of whom 68% presented for follow-up examination. TMD were diagnosed according to research diagnostic criteria for TMD. At baseline examination, the treatment group had a higher frequency of myofascial pain (P=.035) and arthralgia (P=.040) than the control group. At follow-up, the frequencies of myofascial pain, arthralgia and disc displacement had decreased in the treatment group (P=.050, P=.004, P=.041, respectively). The frequency of TMD was comparable in the two groups at follow-up. Patients with dentofacial deformities, corrected by orthodontic treatment in conjunction with orthognathic surgery, seem to have a positive treatment outcome in respect of TMD pain.

Computed tomographic evaluation of the canine intercondylar notch in normal and cruciate deficient stifles.

In the human and veterinary orthopaedic literature it has been implied that intercondylar notch stenosis is a mechanical factor in cranial cruciate ligament rupture and intraarticular graft failure. The patients in this study were classified as normal (32), unilateral cruciate rupture (23), or bilateral cruciate rupture (17). The dogs were placed under general anaesthesia and both stifles were scanned via computed tomography (CT) as previously described. Three CT slices at predetermined levels were evaluated within the notch. Measurements included opening notch angle, notch width and height, condyle width, and notch width index (notch width/condyle width) at two different heights within the notch. Intercondylar notch measurements at the most cranial extent were significantly more narrow in unilateral and bilaterally affected stifles when compared to the normal population. Significant differences were noted in the opening notch angle (ONA), notch width index (NWI), NWI at two thirds notch height (NWI2/3), and tibial slope index (TSI). No significant differences were noted between unilateral and bilateral affected stifles. Increased mechanical contact of the cranial cruciate ligament with a stenotic intercondylar notch may predispose the ligament to mechanical wear and structural weakening. Intercondylar notch measurements have been used as a tool to predict the risk of anterior cruciate ligament injury in young human athletes, and to assess the risk factors for intra-articular graft replacements. Our findings may be useful in developing similar predictive models using stifle CT scans.

The effect of computed tomographical gantry angle on the measurement of the canine intercondylar notch.

This study was conducted to evaluate the clinical application of computed tomography of the canine femoral intercondylar notch. The canine femoral intercondylar notch is angled 12 degrees from the dorsal plane and obliqued 7 degrees proximolateral to distomedial in the sagittal plane. Measurements of the notch were performed with eight, 12, and 16 degrees of gantry tilt. With the exception of proximal opening notch angle, significant differences were not detected in measurements referenced to 12 degrees of gantry tilt. Evidence from this study indicated that a +/- 4 degree variation in gantry tilt angle from a desired angle of 12 degrees did not significantly affect clinical interpretations of intercondylar notch measurements or notch width index ratios.

Temporomandibular disorders, occlusion and orthodontic treatment.

OBJECTIVES: To prospectively and longitudinally study symptoms and signs of temporomandibular disorders (TMD) and occlusal changes in girls with Class II malocclusion receiving orthodontic fixed appliance treatment in comparison with untreated Class II malocclusions and with normal occlusion subjects. DESIGN: Prospective observational cohort. SUBJECTS: Sixty-five girls with Class II malocclusion who received orthodontic treatment, 58 girls with no treatment, and 60 girls with normal occlusion. METHOD: The girls were examined for symptoms and signs of TMD and re-examined 2 years later. Additional records were taken in the orthodontic group during active treatment and 1 year after treatment RESULTS: All three groups included subjects with more or less pronounced TMD, which showed individual fluctuation during the ongoing study. In the orthodontic group, the prevalence of muscular signs of TMD was significantly less common post-treatment. Temporomandibular joint clicking increased in all three groups over the 2 years, but was less common in the normal group. The normal group also had a lower overall prevalence of TMD than the orthodontic and the Class II group at both registrations. Functional occlusal interferences decreased in the orthodontic group, but remained the same in the other groups over the 2 years. CONCLUSIONS: (i) Orthodontic treatment either with or without extractions did not increase the prevalence or worsen pre-treatment symptoms and signs of TMD. (ii) Individually, TMD fluctuated substantially over time with no predictable pattern. However, on a group basis, the type of occlusion may play a role as a contributing factor for the development of TMD. (iii) The large fluctuation of TMD over time leads us to suggest a conservative treatment approach when stomatognathic treatment in children and adolescents is considered.

Signs of temporomandibular disorders in girls receiving orthodontic treatment. A prospective and longitudinal comparison with untreated Class II malocclusions and normal occlusion subjects.

The aim of this investigation was to prospectively and longitudinally study signs of temporomandibular disorders (TMD) and occlusal changes in girls with Class II malocclusion receiving orthodontic treatment and to compare them with subjects with untreated Class II malocclusions and with normal occlusion subjects. Three groups of age-matched adolescent girls were examined for clinical signs of TMD and re-examined 2 years later. Sixty-five Class II subjects received orthodontic fixed straight-wire appliance treatment (Orthodontic group), 58 subjects were orthodontically untreated (Class II group), and 60 subjects had a normal occlusion (Normal group). In the Orthodontic group, the prevalence of muscular signs of TMD was significantly less common post-treatment. The Class II and the Normal groups showed minor changes during the 2-year period. Temporomandibular joint clicking increased in all three groups over the 2 years, but was less common in the Normal group. The Normal group also had a lower overall prevalence of signs of TMD than the Orthodontic and the Class II groups at both registrations. Functional occlusal interferences decreased in the Orthodontic group, but remained the same in the other groups over the 2 years. In conclusion, orthodontic treatment did not increase the risk for or worsen pretreatment signs of TMD. On the contrary, subjects with Class II malocclusions and signs of TMD of muscular origin seemed to benefit functionally from orthodontic treatment in a 2-year perspective. The Normal group had a lower prevalence of signs of TMD than the Orthodontic and the untreated Class II groups.

Temporomandibular disorders and the need for stomatognathic treatment in orthodontically treated and untreated girls.

The aim of this investigation was to study symptoms of temporomandibular disorders (TMD) and headaches longitudinally in girls with Class II malocclusions receiving orthodontic treatment in comparison with subjects with untreated Class II malocclusions and girls with normal occlusion, and to evaluate the need and demand for stomatognathic treatment. The frequency and location of subjective symptoms of TMD and headaches were registered by means of an interview and a questionnaire in three groups of age-matched adolescent girls. Sixty-five Class II subjects received orthodontic fixed straight-wire appliance treatment (Orthodontic group), 58 with Class I malocclusion were orthodontically untreated (Class II group) and 60 had a normal occlusion (Normal group). Individual fluctuations of reported symptoms of TMD were found in all three groups over the 2-year period of the study. Subjects with untreated Class II malocclusions rated their overall symptoms of TMD as more severe than the Orthodontic and the Normal groups. In the Orthodontic group, the prevalence of symptoms of TMD decreased over the 2 years. The overall prevalence of symptoms of TMD was, however, lower in the Normal group than in the other two groups. The need for stomatognathic treatment in the whole sample was estimated to be 13 per cent, while the actual demand was 3 per cent. The large fluctuation of symptoms of TMD over time leads us to suggest a conservative treatment approach when stomatognathic treatment in children and adolescents is considered. The results show that orthodontic treatment did not increase the risk of TMD.

Temporomandibular disorders and mandibular function in relation to Class II malocclusion and orthodontic treatment. A controlled, prospective and longitudinal study.

The relationship between orthodontic treatment and symptoms and signs of temporomandibular disorders (TMD) was studied prospectively and longitudinally in 65 adolescent girls with Class II malocclusion. The subjects received orthodontic fixed appliance treatment with the straight-wire technique combined with or without extractions and were examined for symptoms and signs of TMD before, during, after, and finally one year post-treatment. Both symptoms and signs of TMD showed considerable fluctuations over the three-year period within the individuals. The general tendency was a decreased prevalence of symptoms of TMD over the three years. The prevalence of pain on mandibular movement and tenderness to palpation of the masticatory muscles was significantly less common during and after orthodontic treatment than before. Clinically registered TMJ clicking increased slightly over the three year period. One orthodontic treatment effect when normalizing Class II malocclusions with fixed appliances was a decreased prevalence of functional occlusal interferences. We concluded that the orthodontic treatment either with or without tooth extractions did not increase the risk for TMD or worsen pre-existing signs of TMD. Subjects with Class II malocclusion and pre-treatment signs of TMD of muscular origin seemed rather to benefit functionally from orthodontic treatment in a three-year perspective.

Symptoms and signs of temporomandibular disorders before, during and after orthodontic treatment.

The relationship between orthodontic treatment and symptoms and signs of temporomandibular disorders (TMD) was studied prospectively and longitudinally in 65 adolescent girls with Class II malocclusion. The subjects received orthodontic fixed appliance treatment with the straight-wire technique combined with or without extractions and were examined for symptoms and signs of TMD before, during, after, and finally one year post-treatment. Both symptoms and signs of TMD showed considerable fluctuations over the three-year period within the individuals. The general tendency was a decreased prevalence of symptoms of TMD over the three years. The prevalence of pain on mandibular movement and tenderness to palpation of the masticatory muscles was significantly less common during and after orthodontic treatment than before. Clinically registered TMJ clicking increased slightly over the three year period. One orthodontic treatment effect when normalizing Class II malocclusions with fixed appliances was a decreased prevalence of functional occlusal interferences. We concluded that the orthodontic treatment either with or without tooth extractions did not increase the risk for TMD or worsen pre-treatment signs of TMD. Subjects with Class II malocclusion and pre-treatment signs of TMD of muscular origin seemed rather to benefit functionally from orthodontic treatment in a three-year perspective.

Masticatory efficiency and ability in relation to occlusion and mandibular dysfunction in girls.

PURPOSE: This study investigated the masticatory efficiency and ability in girls with normal occlusion and Class II malocclusion. Furthermore, it investigated the association between masticatory efficiency and ability on one hand and signs and symptoms of temporomandibular disorders (TMD) on the other hand. MATERIALS AND METHODS: A total of 183 girls, aged 11 to 15 years, were included in this study. Sixty subjects had normal occlusion and 123 subjects had Class II malocclusion. The examination included registration of signs and symptoms of TMD. Masticatory efficiency was evaluated with a masticatory efficiency test, while masticatory ability was self-assessed on a visual analog scale. RESULTS: Subjects with normal occlusion presented statistically significantly better masticatory efficiency and ability than subjects with Class II malocclusion. Thirty percent of the variation in masticatory efficiency was explained in a multiple regression analysis. Few occlusal contacts and a large overjet predicted a reduced masticatory efficiency. Subjects who reported frequent temporomandibular joint clicking and subjects who estimated their overall symptoms of TMD as moderate or severe also had reduced masticatory efficiency. CONCLUSION: The authors concluded that masticatory efficiency and ability were partly dependent on the occlusion and that symptoms of TMD influenced the masticatory efficiency and ability.

Symptoms and signs of temporomandibular disorders in girls with normal occlusion and Class II malocclusion.

Mandibular function, headaches, and symptoms and signs of temporomandibular disorders (TMD) were studied in one group of girls with a well-defined normal occlusion (n = 60) and another group with class II malocclusion (n = 123). Frequent headaches and temporomandibular joint clicking, muscle tenderness to palpation, pain on mandibular movement, awareness of tooth clenching, and grinding were commoner in the class II malocclusion group. Awareness of tooth clenching had the largest influence on the odds for symptoms and signs of temporomandibular disorders (TMD) in a logistic regression analysis. Occlusal variables that increased the odds for symptoms and signs of TMD were large overjet, frontal open bite, few occlusal contacts, lateral sliding retruded-intercuspal contact position, crowding, and non-working side interferences. We concluded that normal occlusions have lower odds for symptoms and signs of TMD, whereas some occlusal characteristics, more frequently found in the class II malocclusion group, increased the odds for symptoms and signs of TMD.

Natriuretic response to renal interstitial hydrostatic pressure during angiotensin II blockade.

Increases in renal interstitial hydrostatic pressure (RIHP) increase urinary sodium excretion (UNaV). Experimentally increasing RIHP by direct renal interstitial volume expansion (DRIVE) has been shown to decrease proximal tubule sodium reabsorption. The purpose of the present study was to investigate whether the renin-angiotensin system modulates the natriuretic response to DRIVE. Unilateral nephrectomy and implantation of two polyethylene matrices were performed 3 wk before the acute experiment. Fractional sodium excretion (FENa), RIHP, and glomerular filtration rate (GFR) were measured before and after DRIVE in control rats (n = 9) and in rats receiving the angiotensin II (ANG II) receptor antagonist, losartan potassium (10 mg/kg i.v.; n = 10). DRIVE was achieved by infusing 100 microliters of 2.5% albumin solution directly into the renal interstitium. GFR remained unchanged by DRIVE in both groups. In control animals, DRIVE significantly increased both RIHP (delta 3.8 +/- 0.5 mmHg) and FENa (delta 0.92 +/- 0.19%). In the losartan-treated group, RIHP (delta 2.8 +/- 0.4 mmHg) and FENa (delta 1.93 +/- 0.41%) also significantly increased. The natriuretic response to DRIVE was significantly enhanced during ANG II receptor blockade compared with control animals (delta UNaV/delta RIHP = 2.01 +/- 0.67 vs. 0.44 +/- 0.17 mu eq.min-1 x mmHg-1, respectively; P < 0.05). These results suggest that the blockade of angiotensin enhances the natriuretic response to increased RIHP during DRIVE.

A comparison of electromyography recorded parallel and transverse to the fibres of the anterior and posterior temporalis muscle in man.

Electrical activity recorded during voluntary clenching by platinum hook intra-cutaneous electrodes was significantly higher (p less than 0.01) when the electrodes were placed parallel to the muscle fibres than across the fibres. The correlation between the parallel and transverse EMG recordings was highly significant (p less than 0.001).