Computerized axiography in TMD patients before and after therapy with 'function generating bites'

The study evaluates the temporomandibular joint (TMJ) movements of patients with signs and symptoms of temporomandibular disorders (TMD) before and after therapy with the functional appliances of the 'function generating bite' (FGB) type. Thirty subjects suffering from TMD were selected and divided into two groups: group A (young patients: four males, nine females, mean age +/- standard deviation: 13.3+/-1.5 years); group B (adults: three males, 14 females, mean age +/- standard deviation: 23.2+/-4.4 years). A control group comprised 13 healthy subjects with perfect normal occlusion, TMD-free, was matched for age and sex with patient groups and was examined at T0 and after 12 months (T1). Computerized axiography was performed before and after therapy (average 13 months) with FGBs to evaluate any difference in condyle border movements. Results showed a statistically significant improvement after treatment, for groups A and B, in length, clicks, tracings with normal morphology, superimposition, deviations, regularity and return to starting position and speed (statistical analysis: chi-squared test) except for the symmetry of tracings which was significantly improved only for the young patient group. No statistically significant differences at time T0/T1 were found in the control group. In conclusion, the study shows that the TMJ tracings of TMD patients before and after therapy with 'FGB' significantly improve especially in young patients. FGB may be a useful appliance to improve TMJ function in young and adult TMD patients requiring orthodontic treatment.

Effects of dental amalgam and heavy metal cations on cytokine production by peripheral blood mononuclear cells in vitro

The effects of dental amalgam on cytokine production by human peripheral blood mononuclear cells (PBMC) from healthy donors were analyzed. To induce cytokine production, PBMC were stimulated with lipopolysaccharide, phytohemagglutinin, or staphylococcal enterotoxin A and cultured for 48 h in the presence of either freshly prepared amalgam, aged amalgam, or amalgam-conditioned culture medium (ACCM). The concentrations of several cytokines were measured in PBMC supernatants by enzyme-amplified sensitivity immunoassays (EASIAs). Freshly prepared amalgam as well as ACCM induced a decrease in the production of interferon-gamma (IFN-gamma) and interleukin-10 (IL-10), and an increase in the concentrations of tumor necrosis factor-alpha (TNF-alpha). Both fresh amalgam and ACCM showed no effects on IL-2, IL-6, or granulocyte-macrophage colony-stimulating factor levels. Amalgam aged for 6 weeks did not affect the concentration of any of the above cytokines. To investigate which heavy metal cations released from amalgam caused the observed immunomodulatory effects, Cu2+, Hg2+, and Sn2+, which were detected in amalgam supernatants by inductively coupled plasma atomic spectrophotometry, were added as salts to the cultures. Cu2+ and Hg2+ induced a decrease in IFN-gamma and IL-10 levels, and Hg2+ an increase in TNF-alpha concentrations. Cytokine production was not significantly modulated by Sn2+. Under these experimental conditions, release of Ag+ into culture medium was not detectable. However, Ag+ markedly suppressed the production of IFN-gamma, IL-10, and TNF-alpha. In summary, our results show that fresh amalgam, but not amalgam aged for 6 weeks, causes changes in the cytokine pattern of PBMC in vitro, and that these effects are due to the release of Cu2+ and Hg2+.

Metal ion-induced toxic histamine release from human basophils and mast cells

Recent data suggest that distinct metal ions can be released from dental alloys or other biomaterials, and may cause toxic effects on various cells. In this study, the effects of 14 metal ions on histamine release from human blood basophils (n = 4), isolated tissue mast cells (lung n = 8, uterus n = 2, skin n = 1, gingiva n = 1), the basophil cell line KU-812, and the mast cell line HMC-1 were analyzed. Of the 14 metal ions, Ag+ (0.33 mM) and Hg2+ (0.33 mM) were found to induce release of histamine in blood basophils, KU-812, mast cells, and HMC-1. The effects of Ag+ and Hg2+ were dose dependent and were observed within 60 min of incubation. In primary mast cells and basophils, AU3+ (0.33 mM) also induced histamine release, whereas no effects of Au3+ on HMC-1 or KU-812 cells were seen. The other metal ions showed no effects on primary or immortal cells within 60 min. However, Pt4+ (0.33 mM) induced histamine liberation in HMC-1 and lung mast cells after 12 h. The Ag+- and Hg2+-induced rapid release of histamine from HMC-1 was associated with ultrastructural signs of necrosis, but not apoptosis. In contrast, prolonged exposure to Pt4+ (0.33 mM, 14 h) induced apoptotic cell death in HMC-1 cells, as assessed by electron microscopy and DNA analysis. Together, certain metal ions induce distinct cytopathogenic effects in mast cells and basophils. Whereas Ag+, Hg2+, and Au3+ cause direct toxicity, Pt4 causes cell death through induction of apoptosis. Whether such effects contribute to local adverse reactions to metal-containing biomaterials in vivo remains to be determined.

Lengths of condylar pathways measured with computerized axiography (CADIAX) and occlusal index in patients and volunteers

The lengths of the condylar pathways during protrusive and opening movements were investigated with computerized axiography in 100 individuals. Forty-two patients suffering from anterior disk displacement with reduction (ADD) in one or both temporomandibular joints (TMJ) and 28 patients with anterior overrotation clicking (AOC) of the TMJ were compared with 30 asymptomatic volunteers. Patients suffering from ADD showed significantly shorter tracings than did the two other groups. A significant difference of length of TMJ movement between men and women was found only in one group. The occlusal indices (OI) of the three groups were assessed and compared with each other. Here, a significant difference was found between volunteers and patients suffering ADD and between volunteers and patients with AOC. Between men and women a significant difference of the OI was found in the group with AOC, women presenting higher scores than men. Except for the group of patients with ADD, who showed shorter average lengths, volunteers as well as patients with AOC, were within the normal limits given in the literature for TMJ movement lengths recorded with axiography. The results of this examination therefore indicate that when considering movement length alone no discrimination between healthy and diseased TMJ can be made.

An analysis of hinge axis translation and rotation during opening and closing in dentulous and edentulous subjects

In order to evaluate the influence of interocclusal environment, condylar movement was investigated by computerized axiography. The sample consisted of 50 dentulous and 50 edentulous Caucasians. The mean length of translation at maximum opening in dentulous subjects was 16 mm, while edentulous subjects showed an average of 11 mm. The mean angle of hinge axis rotation at maximum opening was 30 degrees in dentulous subjects and 17 degrees in edentulous subjects. The mean length of translation and the rotation of hinge axis in opening and closing movements was smaller in edentulous subjects than in dentulous ones. In opening and closing movement of edentulous subjects, the length of translation and the rotation value revealed no significant correlation with age or duration of upper and lower prosthesis. No significant difference was shown between edentulous and dentulous subjects on translative quantity in protrusive movement.

Response of L-929 fibroblasts, human gingival fibroblasts, and human tissue mast cells to various metal cations

Recent data suggest that under certain conditions, various metal cations are released from dental alloys. These ions may produce adverse effects in various cell types in vivo. In this study, the cytopathogenic effects of 13 metal cations on murine L-929 fibroblasts, human gingival fibroblasts, and human tissue mast cells were analyzed in vitro. Several metal cations (dose range, from 0.0033 to 1.0 mmol/L) were found to induce dose-dependent inhibition of 3H-thymidine incorporation into cultured fibroblasts. The rank order of potency (lowest observed effect level, LOEL) for L-929 fibroblasts was: Ag+ > Pt4+ > Co2+ > In3+ > Ga3+ > Au3+ > Cu2+ > Ni2+ > Zn2+ > Pd2+ > Mo5+ > Sn2+ > Cr2+. A similar rank order of potency was obtained for primary human gingival fibroblasts: Pt4+ > Ag+ > Au3+ > In3+ > Ga3+ > Ni2+ > Co2+ > Zn2+ > Cu2+ > Cr2+ > Pd2+ > Mo5+ > Sn2+. In primary human mast cells, Ag+ and Au3+ caused dose-dependent toxic histamine release, whereas the other metal cations were ineffective over the dose range tested. To investigate the mechanism of metal cation-induced effects, we performed DNA as well as electron microscopic analyses on cultured fibroblasts. Both the DNA pattern and the ultrastructure of L-929 cells and gingival fibroblasts after exposure to cytopathogenic metal cations revealed signs of necrosis but no signs of apoptosis. Together, our data provide evidence that various metal cations produce dose-dependent cytopathogenic effects in distinct cell types, including human gingival fibroblasts and human tissue mast cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental and periodontal disease in patients with cirrhosis--role of etiology of liver disease

BACKGROUND/AIMS

Bacterial infections are frequent complications in patients with cirrhosis, especially in alcoholics. A potential source of infection may be dental foci. The aim of the study was to assess the role of cirrhosis and chronic alcoholism in the development of dental or periodontal disease.

METHODS

Dental and periodontal examinations were performed prospectively in 97 patients with cirrhosis (alcoholic: 64, nonalcoholic: 33), in 68 alcoholics without cirrhosis and in 71 healthy subjects (subdivided into age groups: 21-30, 31-40, 41-50, and 51-60 years).

RESULTS

Measures of oral hygiene (p < 0.01), dental care (p < 0.001), and periodontal parameters were worse and the number of teeth requiring treatment (p < 0.001) was higher in alcoholics with or without cirrhosis than in healthy subjects and nonalcoholic patients with cirrhosis. Alcoholics had a lower total number of teeth than patients without alcohol abuse and healthy controls (p < 0.05). The dental and periodontal status of patients with nonalcoholic cirrhosis did not differ from the control group. The severity and duration of liver disease had no influence on dental and peridontal disease.

CONCLUSION

The presence of cirrhosis itself, therefore, is not a predisposing factor for dental and periodontal diseases. In alcoholics, these diseases appear to be caused primarily by bad oral hygiene and poor dental care.

The effect of occlusal splint therapy on different curve parameters of axiographic TMJ tracings

Computerized axiography was used as an objective instrumental method of evaluating the response of patients with temporomandibular joint (TMJ) symptomatology to occlusal splint therapy. Diagnosis was performed in a standardized manner by systematically analyzing TMJ path tracings obtained by computerized axiography. Thirty-six patients were axiographed before and after therapy with full-arch occlusal stabilizing appliances, followed by assessing the effect of therapy on various path curve parameters. The data obtained for the patient group treated with splints was compared to that of six patients also axiographed, but left untreated for a period of six weeks before a second TMJ tracing was obtained. The results show that splints have a certain effect on reciprocal TMJ clicking (response rate 67%). Retral stability and path characteristics are also substantially improved (response rates 44% and 40%). Less influence was noted on hypomobile joint paths (response rate 29%), the quality of movements (response rate 28%) and Bennett angle values (response rate 23%). Patients with disk displacements without reduction were not treated with splints, they underwent surgery. Their results will be reported later. By contrast, TMJ tracings in the control group remained essentially unchanged.

Orthopedic jaw movement observations. Part V: Transversal condylar shift in protrusive and retrusive movement

Unguided protrusive and retrusive mandibular movement was investigated in 76 asymptomatic volunteers and temporomandibular joint (TMJ) patients using computerized axiography. In 38 of these subjects, guided pro-/retrusion was also recorded. Measurements were performed in a three-dimensional Cartesian coordinate system (x = anteroposterior; y = transversal, toward the hinge axis; z = craniocaudal). Transversal shift (y) was measured and evaluated as well as the distance "s" and horizontal condylar inclination (HCl) at the point of maximum transversal deviation. The patterns of the tracings were analyzed with a view to diagnostic improvements. The objective of this study was to evaluate transversal shift and to examine the postulate of symmetrical behavior of the TMJs in pro-/retrusion. The mean mandibular shift was 0.15 mm to the left. This maximum deviation was seen in a mean distance "s" of 7.42 mm in relation to the Cartesian coordinate system in reference position. These results suggest a functional dominance of the right part of the mandible in protrusive and retrusive movement.

Recording orthopedic jaw movements. Part IV: The rotational component during mastication

The recording and analysis of mastication provides information on neuromuscular engrams, and hence avoidance mechanisms. Avoidance mechanisms are pathologic movement patterns which are developed to avoid occlusal interferences during functional movements. Evaluation of hinge-axis rotation permits selective quantitative analysis of a complex movement pattern. The objective of this study was to determine the amount of hinge axis rotation in mastication using computerized axiography. Furthermore, the distance of the condyles from reference position (RP) at maximum rotation was evaluated and the chronological sequence of translation and rotation was investigated. The mean value for the rotational angle of the mandible (gamma) during mastication was 14.1 degrees in the volunteers and 13.44 degrees in the patients. The linear spatial distance from RP amounted to a mean of 6.57 mm on the right side and 6.21 mm on the left in the volunteers. In the patients, the measurements were 6.33 mm on the right side and 6.7 mm on the left. In most cases, maximum rotation did not correspond with maximum translation. The chronological sequence of maximum excursion was not constant.

Orthopedic jaw movement observations. Part III: The quantitation of mediotrusion

The objective of this series is to observe and analyze movements of the temporomandibular joint (TMJ). With the information from these studies, orthopedic standards for jaw movements will be established in further investigations according to the neutral-zero method used in general orthopedics. Any restricted range of motion can thus be defined as a deviation from these standards. Direct interpretation and objective evaluation of joint functions has major practical implications. With the aid of computerized axiography, mediotrusive movements of 48 asymptomatic volunteers and 66 jaw patients were evaluated. The movements performed were either free or guided. The mean curve lengths, as well as the Bennett angles at 3 mm and at the end point were recorded. An average group was defined, containing the values of 50% of all volunteers. The interquartile range was calculated for lengths of mediotrusive movements as well as for Bennett angles. The average range of free mediotrusive movement for female volunteers was 11.06-11.98 mm (mean 11.55 mm) on the right side and 10.47-11.75 mm (mean 11.24 mm) on the left side. Male volunteers showed an average range of 10.23-11.54 mm (mean 11.1 mm) on the right side and 10.24-11.73 mm (mean 11.12 mm) on the left side. The values for female patients amounted to 9.95-1.66 mm (mean 10.8 mm) on the right side and 9.75-11.28 mm (mean 10.55 mm) on the left side. The average range for male patients was 9.06-9.71 mm (mean 9.54 mm) on the right side and 9.17-10.23 mm (mean 9.73 mm) on the left side. The average range for Bennett angles at maximum excursion in free mediotrusive movement was between 0.41 and 5.89 degrees (mean 4.43 degrees) in the volunteers on the right side and between 2.45 and 10.07 degrees (mean 6.87 degrees), respectively, on the left side. The values for patients amounted to 0.19-12.65 degrees (mean 6.93 degrees), on the right side and 1.71-14.15 degrees (mean 6.73 degrees) on the left side.

Orthopedic jaw movement observations. Part II: The rotational capacity of the mandible

Using computerized axiography, particularly the electronic mandibular position indicator (EMPI), the mandibular opening movement was measured in 86 asymptomatic volunteers and temporomandibular joint (TMJ) patients. Terminal hinge-axis movement and hinge-axis rotation at maximum-guided mouth opening were recorded. The angle of hinge-axis rotation was used as a parameter for both movements, in accordance with the neutral-zero method. This is a well-established technique in orthopedics and is the standard tool for quantitative functional analysis of joints. An average group was defined, 50% being volunteers. The interquartile range for terminal hinge-axis movement in this study was 5.42 degrees-7.41 degrees in the volunteers and 4.73 degrees-7.25 degrees in the patients. The interquartile range for hinge-axis rotation at maximum opening was from 29.09 degrees-34.87 degrees in the volunteers and from 26.7 degrees-35 degrees in the patients. Computerized axiography is a refined tool for analyzing rotational and translational capacities of the mandible. It is a valid and practical method for orthopedic-diagnostic evaluation of mandibular movements and gives objective criteria for diagnosis in accident victims.

Orthopedic jaw movement observations. Part I: Determination and analysis of the length of protrusion

An analysis and quantitation of protrusive and retrusive mandibular movement is provided. This report is one study along with four other parts analyzing the mandibular opening movement, the transversal shift during protrusion and retrusion, the mediotrusive movement and mastication. Protrusive movements of 225 individuals (180 patients, 45 volunteers) were analyzed using computerized axiography. Investigating both asymptomatic volunteers and patients with abnormal joint mobility helps to improve evaluation of these abnormalities. With the aid of diagnostic computer software, the length of the pathways was measured and the characteristics of the curves were analyzed. An average group was defined based on the values found in asymptomatic individuals, comprising 50% of our volunteers. The interquartile range for the male volunteers was 8.79-12.27 mm for the right joint and 9.43-12.93 mm for the left joint; for female volunteers it was 8.32-10.64 mm and 9.2-11.26 mm, respectively.

[MRI of the temporomandibular joint. Demonstrability and significance of the retro-articular vascular plexus]

The retro-articular vascular plexus of the temporomandibular joint (TMJ) is of great importance for the function of this joint. Aim of this study was to determine the amount of increase of signal intensity in the retro-articular vascular plexus after intravenous injection of contrast medium and to figure out potential advantages of this procedure. The posterior band of the articular disc--a landmark in the diagnosis of disc dislocations--becomes prominent after injection of contrast medium. Forty-five temporomandibular joints were studied before, and after intravenous injection of contrast medium with magnetic resonance imaging (MRI) using T1-weighted images in parasagittal plane. In all cases a measurable increase of signal intensity was demonstrable in healthy volunteers as well as in patients with normal or pathological TMJ findings. In 53.3% of cases the posterior band was better differentiable after administration of contrast medium. In patients with suspicion of pathological features in series without contrast medium, in 27.3% of those cases administration of contrast medium led to a more precise--"diagnostic"--evaluation of disc location. The study emphasizes the use of contrasts medium for evaluations of disc dislocation with MRI in cases of pathological or unclear findings in precontrast MRI series.

Palladium in dental alloys--the dermatologists' responsibility to warn?

Palladium is increasingly used in industry, but also in fine jewelry and in dentistry. Thus, palladium-silver alloys comprise a substantial part of the noble metal ceramic alloy sales in Western countries. The increased use of this metal seems, however, to be paralleled by a rise in the number of reports of palladium allergy. Recently a European study reported a sensitization rate of 2.8%. In Austria, where palladium has started to displace amalgam in dental fillings because of concerns about mercury toxicity, and gold due to price factors, we have found a sensitization rate of 8.3% in unselected eczema patients. Despite the current lack of clear clinical relevance of this finding, these numbers should motivate us to question this substance as "the alloy of the future".

Computerized axiography: principles and methods

This paper reviews earlier methods for the analysis of mandibular movement and gives a detailed account of state-of-the-art procedures. Special emphasis is given to computerized axiography and the application of this method to the diagnostics of the temporomandibular joint (TMJ). The article discusses the advantages of computerized axiography over the mechanical device and points out the limitations of the axiographic method. One major advantage of the computerized system is having the enlarged diagram of tracings on the computer screen. This means that small changes such as initial disk displacements can be diagnosed more readily than with the mechanical device.