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Objective. To investigate the suitability of measurements of mercury (Hg) concentration as a means of identifying patients with health complaints attributed to dental amalgam. Methods. Hg in erythrocytes, plasma, urine, and saliva was determined in 27 patients complaining about health problems attributed to amalgam, 27 healthy volunteers with amalgam fillings, and 27 healthy amalgam-free volunteers. Results. Concentrations of inorganic mercury in blood and of total mercury in urine and saliva differed significantly between individuals with amalgam fillings and amalgam-free volunteers, but not between symptomatic patients and healthy volunteers with amalgam fillings. Urine Hg levels tended to be better correlated with blood than with saliva data. Levels of organic Hg were equal in all groups. Conclusion. Concentrations of total and inorganic mercury in body fluids do not distinguish between asymptomatic amalgam bearers and those who suffer from a poorly defined syndrome of multiple nonspecific symptoms.

Objective: We aimed to investigate whether the Prognos® device might be a useful tool in the diagnosis of disorders suspected to be due to dental amalgam fillings. Participants and Methods: A diagnostic case-control study was performed in 27 patients who complained about health problems attributed to amalgam (cases), 27 healthy volunteers with amalgam fillings (controls I), and 27 healthy amalgamfree volunteers (controls II). All participants were tested before and after application of 300 mg DMPS (2.3-dimercapto- 1-propanesulfonic acid) with Prognos®, a diagnostic device for the energetic measurement of Traditional Chinese Medicine meridians. In addition, mercury was measured in blood, urine, and saliva, and a lymphocyte transformation test (LTT) was performed. Results: Diagnoses derived from the first and second Prognos® testing did not agree above chance (Cohen’s Kappa = -0.11, 95% confidence interval -0.33 to 0.10; p = 0.30). Agreement for secondary outcome measures was poor, too. Prognos® measurements did not differ between cases and controls. Correlations with measurements in urine, blood and saliva were low. Conclusion: In this study Prognos® could not be shown to be a useful tool in the diagnosis of disorders suspected to be due to dental amalgam fillings.

Few long-term clinical studies have reported data of modern posterior composites as direct and indirect restorations.This prospective, long-term clinical trial (1) evaluated direct and indirect composite restorations for clinical acceptability as posterior restoratives in single or multisurface carious teeth and (2) provided a survey on the 2-year results.Nine dental students placed 88 composite restorations (Tetric, blend-a-lux, Pertac-Hybrid Unifil), 43 direct composite restorations and 45 indirect inlays, under the supervision of an experienced dentist. The first clinical evaluation was performed 11 to 13 months after placement by 2 other experienced dentists, using modified USPHS criteria. A second follow-up of 60 restorations took place within 20 to 26 months after placement.A total of 93% of indirect and 90% of direct composite restorations were assessed to be clinically excellent or acceptable. Two restorations (1 indirect composite inlay and 1 margin of a direct composite restoration) failed during the second year because of fracture. Indirect inlays demonstrated a significantly better "anatomic form of the surface" than direct composite restorations. Premolars revealed a significantly better margin integrity and postoperative symptoms than molars.Posterior composite restorations provided a satisfactory clinical performance over a 2-year period when placed by relatively inexperienced but supervised students.

It was the aim of this investigation to treat 20 volunteers with maximally 5 amalgam fillings by the same comprehensive protocol in which all removals with (n = 8) and without (n = 12) rubber dam had been performed within a few months. Nine amalgam-related parameters indicated a close matching of both groups before removal. In the group without rubber dam, mercury (Hg) levels in plasma increased significantly above preremoval values at days 1 and 3 after removal; they decreased significantly below preremoval values at day 30 in the rubber-dam group and at day 100 in both groups. Excretion rates did not increase significantly in either group, but decreased significantly at day 100 in the protected group. Peak plasma-Hg was 0.6 ng/mL on average at day one and decreased with halftimes of 3 and 43 d in subjects protected by rubber dam. The results indicated that concentrations of total mercury in plasma responded rapidly to changes in the amalgam status and reflected the actual absorption most reliably. Notably, plasma-Hg levels were sensitive enough to detect a transient attenuation of the additional exposure by using rubber dam during the removal of only a few fillings. However, being small in magnitude and lasting 100 d at best, the rubber-dam effect had minor toxicological relevance.

The aims of this study were to examine whether there is a difference in symptoms between patients with amalgam fillings and patients without such restorations, to investigate the relationship between particular symptoms and the number of amalgam filled surfaces, and the differences in symptoms between patients with and without removal of amalgam fillings. Data from 6744 consecutive patients in 34 dental offices located throughout Germany were documented. Patients completed a questionnaire answering 48 items, and the current oral findings in the patients were registered. The analysis was restricted to 4,787 patients aged 21 to 60 yr because of special dental conditions in children and elderly persons. The study did not show any significant correlation between the intensity of complaints or particular groups of symptoms and the number of amalgam-filled surfaces. A higher number of symptoms as well as a higher intensity of symptoms were found in patients before amalgam removal compared to the remaining patients. The question remains open whether or not there may be a certain kind of relationship between the complaints and amalgam fillings in individual patients.

The number of amalgam-covered surfaces and the occlusal area of the fillings, the concentrations of total mercury in plasma, erythrocytes and urine, the urinary excretion rate, and the absorbed daily doses estimated by two separate methods from intra-oral Hg emission were determined in 29 volunteers with a low amalgam load. The transfer ofHg from the fillings via the oral cavity and blood to urinary excretion was evaluated by multiple correla tions between these variables. In addition, the combina tion of variables most representative of the entire compartmental transfer of amalgam Hg was determined. Urinary excretion (1), Hg concentration in plasma (2) and absorbed dose (3) were most closely correlated to each other, followed by correlations with the variables of the fillings (4). Correlation coefficients were 0.75 for variables 1 vs 2 and 2 vs 3, and 0.49 for variables 3 vs 4. It was concluded that variables 1-3 best reflected the transfer of mercury from amalgam fillings throughout the organism and that they were relatively insensitive to dietary mercury. The determination of total mercury in plasma and of its urinary excretion rate appears, under practical aspects, most suitable for the investigation of Hg uptake from amalgam.

Objectives The aim of this investigation was to determine the influence of a variety of parameters on the effectiveness of hard substance ablation and the thermal side effects when using Er:YAG laser (Key I and II, KaVo) and Nd:YAG laser (SunLase 800, Sunrise Technologies/Orbis). Methods For this study, ablation and temperature measurements were carried out on 170 dentin slices and 170 extracted teeth via computer-controlled cavity preparation. The Er:YAG laser settings varied from 250 – 400 mJ/pulse, 3 –15 pps and 20 –180 s processing time, and in the case of the Nd:YAG laser from 83 – 100 mJ/pulse, 10 – 20 pps, and 20 – 280 s processing time. The ablation rate was measured volumetrically via a 3D sensor. Temperatures were measured for each setting both on the dentin slice and in the pulp of the extracted teeth. The results were analyzed using a Mest for independent samples and a one-way ANOVA (Bonferroni). Also a liner regression analysis was done using Pearson's coefficient. Results The results show that with the Er:YAG laser, in combination with water-spray cooling, an effective 3D ablation rate (up to 0.017 mm 3 /pulse = 50 pm linear) can be achieved without raising the temperature of the surrounding tissue. In the case of the Nd:YAG laser, no measurable ablation rate was evident without conditioning of the dentin surface and, in the case of conditioning with black ink, a low ablation rate (0.00004 mm 3 /pulse = linear 0.2 pm/pulse) was found. Significance In contrast to the Er:YAG laser, it is apparent, that with the Nd:YAG laser from a total energy of 80 J onwards, the rise in temperature in the pulp is above 8°C. For that reason, the use of the Nd:YAG laser at higher total energies is not recommended. The temperature rise with the Nd:YAG laser is dependent on the direction of the dentin tubuli. Dentin tubuli running parallel to the surface prevent significant heat penetration, whereas those running in a transverse direction to the surface (= parallel to the laser beam) support the penetration of heat. This finding supports the light-propagating theory for spreading effects of laser beams in dentin.

In the course of a prospectively designed long-term clinical trial, composite fillings and inlays were evaluated for clinical acceptability as restorative materials in one, two or more surface cavities of posterior teeth over a 1-year period. In 45 patients, 88 restorations were placed by nine student operators, under the supervision of an experienced dentist, to compare the two half sides using the composite resins Tetric (Vivadent), blend-a-lux (Blend-a-med), and Pertac-Hybrid Unifil (Espe). The first clini-cal follow-up check took place within a time period of 11 – 13 months after placement of the restorations using modified USPHS criteria. The interpretation of the clinical criteria showed satisfactory results over this time period: more than 85% of the inlays and direct fillings were rated ``alpha'' or ``bravo'', using the parameters of assessment defined in this study. Only three restorations (two fillings, one inlay), all in molars, were rated ``delta'', i. e., unacceptable. The reasons for their replacement were mar-ginal opening, secondary caries, and loss of sensitivity. For the criteria ``surface texture'', ``anatomical form of the surface'', and ``occlusion'', composite inlays were significantly better than composite fillings. These results indicate that posterior composite restorations provide acceptable and excellent clinical service, even if they are placed by relatively inexperienced student operators.

Bei der Analyse moglicher Schmelzschaden bei der Bracketentfernung wurden die Methoden der tordierenden und der biegenden Bracketentfernung miteinander verglichen. In jeder Testgruppe befanden sich 19 extrahierte menschliche Molaren, an denen Metallbrackets mit Concise im Saure-Atz-Verfahren befestigt worden waren. Die Bracketentfernung erfolgte standardisiert in einer Wolpert-Universalprufmaschine TZZ 707 mit modifizierter Torsions-bzw. Biegemechanik. Die Schmelzoberflache wurde anhand rasterelektronenmikroskopischer Bilder analysiert. Bei tordierender Bracketentfernung betragen die Schmelzausrisse im Mittel 48,3% der von Kleberresten freien Schmelzoberflache. Sie reichen haufig in tiefe Schmelzschichten und treten bevorzugt an den Breitseiten des Klebeareals auf. Bei biegender Bracketentfernung wurden Schmelzausrisse wesentlich seltener beobachtet und waren meist nur oberflachlich lokalisiert. Sie traten fast ausschlieslich an den Druckzonen auf. Die zur Bracketentfernung notwendige Kraft sowie die anhand mechanischer Modelle berechnete Kraftverteilung korrespondieren mit dem aufgetretenen Schmelzschaden. Es ergibt sich als Schlusfolgerung, das der Methode der Bracketentfernung eine klinisch relevante Bedeutung zukommt.

The aim of the present study was to compare the reduction of subjective complaints by 3 treatment strategies in 90 “amalgam patients” whose complaints could not be explained by a medical or psychological disorder. The individuals were randomly assigned either to removal of dental amalgam only (removal group), or removal in combination with a “biological detoxification” therapy with high doses of vitamins and trace elements (removal-plus group), or participation in a health promotion program without removal of dental amalgam (no-removal group). Between baseline and month 12, the sum score of main complaints decreased by 3.5 (SD = 2.2) points on average in the removal group as well as in the removal-plus group, and by 2.5 (SD = 2.4) points in the no-removal group (p = 0.152). Both removal groups showed a significant decrease in steady-state levels of inorganic mercury compared with the no-removal group. Thus, all 3 interventions were associated with clinically relevant improvements.

Parts of the population are permanently exposed to low levels of Hg degrees and Hg(II) from dental amalgam. It was the aim (1) to investigate the internal exposure to amalgam-related mercury from the kinetics of inorganic Hg in plasma and erythrocytes after amalgam removal, and (2) to estimate the amalgam-related absorbed dose. Dietary coexposure was monitored by determination of blood organic-Hg. Postremoval steady-state Hg concentrations were measured for 18 months. Eighty-two patients had been randomized into three groups: (A) removal of the fillings; (B) removal and non-specific detoxification, and (C) a health promotion program without removal. After amalgam removal, inorganic Hg dropped rapidly in plasma and red cells, stabilizing at 27% of preremoval levels after 60 days. Concentrations of organic Hg in plasma remained unchanged, indicating no change in dietary uptake of organic Hg. The concentration of organic Hg in red cells of group A was in the early postremoval phase lower and in the late postremoval phase higher than the preremoval control (p

In 29 volunteers with a low amalgam load, the number of amalgam-covered tooth surfaces and the occlusal area of the fillings were determined. Before and at select times after removal of all amalgams, concentrations of total mercury were measured by cold-vapor atomic absorption in plasma and erythrocytes as well as in urine together with the excretion rate. Absorbed daily doses were estimated from intraoral Hg emission by two separate methods. The transfer of Hg from the fillings via the oral cavity and blood to urinary excretion was evaluated according to the most representative combination of parameters. This consisted of occlusal area (1), absorbed dose (2), Hg concentration in plasma (3) and urinary excretion (4). Pairwise correlation coefficients were 0.49 for parameters 1 vs. 2, and 0.75 each for parameters 2 vs. 3 and 3 vs. 4. Within 9 days after removal of the fillings, a transient increase in Hg levels was observed in plasma only; in the group without a rubber dam, concentrations increased significantly above pre-removal values at days 1 and 3, whereas they decreased significantly below pre-removal values at day 30 in the rubber-dam group and at day 100 in both groups. Excretion rates decreased significantly at day 100 in the protected group. Peak plasma-Hg was 0.6 ng/ml on average at day 1 and decreased with halftimes of 3 and 43 days in subjects protected by a rubber dam. The results indicated that concentrations of total mercury in plasma responded rapidly to changes in the amalgam status and reflected the actual absorption most reliably. Notably, plasma-Hg levels were sensitive enough to detect a transient attenuation of the additional exposure after using a rubber dam during the removal of only a few fillings. However, being small in magnitude and lasting 100 days at best, the rubber-dam effect had minor toxicological relevance.

Statement of the Problem. Objective long-term clinical data are necessary to assess the performance of modern posterior composites as direct and indirect restorations. Purpose. This prospective, long-term clinical trial evaluated direct and indirect composite restorations for clinical acceptability as posterior restoratives in single or multisurface cavities and provided a survey on the 3-year results. Material and Methods. Under the supervision of an experienced dentist, 9 dental students placed 88 composite restorations (Tetric, blend-a-lux, Pertac-Hybrid Unifil), 43 direct composite restorations, and 45 indirect inlays. Clinical evaluation was performed at baseline and in yearly intervals after placement by 2 other experienced dentists, using modified USPHS criteria. A third follow-up of 60 restorations took place within 33 to 36 months after placement. Results. A total of 93% of indirect and 87% of direct restorations were assessed to be clinically excellent or acceptable. During the third year, 1 direct restoration in a molar failed because of margin opening. Indirect inlays exhibited a significantly better anatomic form of the surface than direct composite restorations. Premolars revealed a significantly better marginal integrity and anatomic form of the surface than molars. Restorations in molars exhibited a significantly higher failure rate compared with premolars. Conclusion. Posterior composite restorations provided a satisfactory clinical performance over a 3-year period, even if placed by relatively inexperienced but supervised students. (J Prosthet Dent 2000;84:289-96.)

It was the aim of this investigation to treat 20 volunteers with maximally 5 amalgam fillings by the same comprehensive protocol in which all removals with (n = 8) and without (n = 12) rubber dam had been performed within a few months. Nine amalgam-related parameters indicated a close matching of both groups before removal. In the group without rubber dam, mercury (Hg) levels in plasma increased significantly above preremoval values at days 1 and 3 after removal; they decreased significantly below preremoval values at day 30 in the rubber-dam group and at day 100 in both groups. Excretion rates did not increase significantly in either group, but decreased significantly at day 100 in the protected group. Peak plasma-Hg was 0.6 ng/mL on average at day one and decreased with halftimes of 3 and 43 d in subjects protected by rubber dam. The results indicated that concentrations of total mercury in plasma responded rapidly to changes in the amalgam status and reflected the actual absorption most reliably. Notably, plasma-Hg levels were sensitive enough to detect a transient attenuation of the additional exposure by using rubber dam during the removal of only a few fillings. However, being small in magnitude and lasting 100 d at best, the rubber-dam effect had minor toxicological relevance.

Antigen (Ag)-triggered activation of T cells requires engagement of both the T-cell Ag receptor and a costimulatory receptor, for which CD28 can function as a prototypical example. CD80 and CD86 represent ligands for this receptor, and although they are present on professional Ag-presenting cells, these molecules are absent from most tumors. Yet some tumors are still able to costimulate a T-cell response, while others cannot. Therefore, a key question concerns the molecular basis for the costimulation of T cells by those tumor cells not expressing the CD28 ligands CD80 and CD86. Upon screening a cDNA library of such a tumor cell line in a transient COS cell transfection assay for costimulatory activity, we identified Ran/TC4 as a protein whose overexpression results in costimulatory activity. Ran/TC4 is a ubiquitously expressed member of the Ras gene superfamily of small guanosine triphosphate-binding proteins and is involved in nuclear transport; Ran/TC4 cDNA-transfected COS cells specifically costimulate CD8 T cells and not CD4 T cells. Transfection of Ran/TC4 into the costimulation-deficient murine RMA lymphoma cell line introduced costimulatory capacity for CD8 T cells and resulted in markedly elevated levels of nuclear Ran/TC4 protein expression. In addition, in vivo priming of mice with Ran/TC4-transfected RMA cells induced protection against wild-type (wt) RMA tumor cells. Ran/TC4-transfected RMA cells and wt RMA tumor cells exhibit comparable in vivo growth rates in mice lacking T and B cells, and Ran/TC4-mediated tumor rejection thus involves B and/or T cells. This possibility is substantiated by the observation that T cells from normal mice challenged with Ran/TC4-transfected RMA cells can mount a cytotoxic T-cell response not only against the Ran/TC4-transfected tumor cells but also against wt RMA tumor cells. Based on these results, we conclude that gene transfer-mediated elevations in Ran/TC4 can confer costimulatory function for CD8 T cells to tumor cells. This finding suggests a novel application of Ran/TC4 as a protein capable of regulating costimulation in tumor cells.

The aims of this study were to examine whether there is a difference in symptoms between patients with amalgam fillings and patients without such restorations, to investigate the relationship between particular symptoms and the number of amalgam filled surfaces, and the differences in symptoms between patients with and without removal of amalgam fillings. Data from 6744 consecutive patients in 34 dental offices located throughout Germany were documented. Patients completed a questionnaire answering 48 items, and the current oral findings in the patients were registered. The analysis was restricted to 4,787 patients aged 21 to 60 yr because of special dental conditions in children and elderly persons. The study did not show any significant correlation between the intensity of complaints or particular groups of symptoms and the number of amalgam-filled surfaces. A higher number of symptoms as well as a higher intensity of symptoms were found in patients before amalgam removal compared to the remaining patients. The question remains open whether or not there may be a certain kind of relationship between the complaints and amalgam fillings in individual patients.

In 29 volunteers with a low amalgam load, the number of amalgam-covered tooth surfaces and the occlusal area of the fillings were determined. Concentrations of total mercury were measured in plasma and erythrocytes as well as in urine together with the excretion rate. Absorbed daily doses were estimated from intraoral Hg emission by two separate methods. The transfer of Hg from the fillings via the oral cavity and blood to urinary excretion was evaluated according to the most representative combination of parameters. This consisted of urinary excretion (1), Hg concentration in plasma (2), absorbed dose (3), and occlusal area (4). Pairwise correlation coefficients were 0.75 for parameters 1 vs 2 and 2 vs 3 and 0.49 for parameters 3 vs 4. Within 9 days after removal of the fillings, a transient increase was observed in plasma Hg levels only. This was reduced in those volunteers to whom a rubber dam had been applied during removal. Peak plasma Hg was 0.6 ng/ml on average and decreased with halftimes between 5 and 13 days. A significant decrease in Hg excretion was noted not before 100 days after removal. Being relatively insensitive to dietary mercury, the determination of total mercury in plasma and of its urinary excretion rate appears, under practical aspects, most suitable for the investigation of Hg uptake from amalgam.

The development of computer aided technology in restorative dentistry has created a range of techniques for the modern dentist. The types of systems now available and the literature published thus far on long term clinical results of restorations created by such techniques are reviewed.

Inadequate adaptation of a filling material to a gold crown can promote the passage of bacteria; thus, recontamination of sound dentin and/or the pulp canal space is feasible. The aim of this study was to determine the marginal microleakage between two different amalgams (Tytin and Valiant PHD-XT), three different composites (Tetric, Charisma, and Polofil Molar), and one glass-ionomer cement (Ketac Silver) and gold cast crowns using a helium gas microleakage method. In order to standardize the research parameters, gold washers with standardized dimensions were used as study models together with a helium leakage testing device. Standardized cavities were filled according to the manufacturers' recommendations with the different materials. The amount of helium passing the marginal interface between the fillings and cavities was measured with a mass spectrometer 48 hours after the fillings were placed and 100, 1000, and 2000 thermocycles (5 degrees C-55 degrees C). The results showed that amalgam allowed the least microleakage. Ketac Silver showed the greatest microleakage. Statistically significant differences were found between the composites and both amalgams and Ketac Silver between the 48-hour and 100-thermocycling groups. Yet, Ketac Silver showed a significant ascending tendency when compared to the composites and amalgams after 100, 1000, and 2000 thermocycles.

Two different methods of removing brackets, on the one side by torsion and on the other by bending, were compared for the purpose of analyzing the respective enamel lesions. Each test group consisted of 19 extracted human molars with metal brackets attached to the molars by means of the "concise etching technique". Bracket removal was standardized through the use of a Wolpert "Universalprüfmaschine TZZ 707" with modified torsion and bending mechanism. A scanning electron microscope was used to analyze the enamel surface. When using the torsion method, the mean extension of the enamel lesions was 48.3% of the adhesive free enamel surface. These lesions often reached into the deeper enamel layers and were mainly to be found on the broad side of the bonded area. On the other hand, when using the bending method, the enamel lesions were less frequent. They were mainly superficial and were confined almost exclusively to the pressure zones. The stress required to remove the brackets and the stress distribution were calculated on mechanical models and these results corresponded well with the enamel lesions observed on the molars. It can thus be concluded that the method of removing brackets is clinically relevant in relation to enamel lesions.

Festsitzende kieferorthopadische Apparaturen verursachen besondere Probleme bei der Durchfuhrung der taglichen Mundhygiene. In der vorliegenden Untersuchung wurde durch eine einfache Methode eine Losung dieses Problems beschrieben und deren Effizienz in einer klinischen Untersuchung nachgewiesen.

The effectiveness of two tooth cleaning methods (Roll and Bass technique) was evaluated in 28 patients. Answers to the following questions were sought: 1. Which of the two methods results in greater reduction of plaque formation? 2. Are difficulties encountered in the learning and practice of each method? 3. Which method gives better results in the less accessible parts of the jaws? A significant difference in the cleaning effectiveness of the two methods could not be demonstrated.

The technique of acid cauterisation is only effective in the area of the enamel. The technique of preparation has to be modified if fillings go beyond the area of the enamel. Those modifications and solutions are discussed which combine the anchoring possibilities of conventional preparations with the technique of acid cauterisation.

For the preclinical instruction of dental students and the training of dental assistants a working place has been developed which, in contrast to the phantom tables used so far, better simulates clinical treatment of patients.

The forameter is an instrument used for measuring the length of the root canal. Here the use of the principle of resistance measurement is refined. The position of the apical foramen is shown acoustically as well as visually. This investigation gives positive results for the measurements in the treatment of devitalised teeth. The inaccuracy of measurement in living teeth appears too great.

The endodontic work of students in the department for tooth conservation at the Dental Hospital in Mainz, FRG, during 1975 was described. A total of 850 cases were studied in regard to the following: 1) cause and type of endodontic treatment, 2) type of root filling material, 3) number of appointments, 4) temporary root canal filling with limited period of storage, 5) degree and homogeneity of the filling.