Search PubMed⌕ Search

Biomedical subjects

G Schmalz

Publications and source records attributed to G Schmalz.

At least 55 records · Page 3Linked to original sources
PubMed1999

Clinical performance of polyacid-modified resin restorations using "softstart-polymerization".

This study investigated the influence of "softstart-polymerization" on the clinical performance and marginal integrity of polyacid-modified resin restorations (PMR) in class V cavities. Eighty PMR restorations were placed in 20 patients [40 Dyract (DY); 40 Hytac (HY)] with (npat = 10) and without preparation (npat = 10). Restorations were light cured for 40 s either conventionally (CP) or with a lower light intensity for the first 10 s (SSP). Each patient received four restorations (DY-CP, DY-SSP, HY-CP, HY-SSP), which were examined clinically according to modified USPHS criteria, and by quantitative SEM-analysis after 7 days (baseline), 6 months and 1 year. Statistical analysis was performed using the Mann-Whitney-U test (P < or = 0.05) and error rates method. Clinically, no restoration showed recurrent caries or crevices. After 1 year, margins of 24-47% of the HY- and 36-53% of the DY-restorations were rated "Bravo". Marginal discoloration occurred in 20-37% in HY- and in 18-21% in DY-restorations. The error rates method revealed no significant differences between materials or between polymerization modes with and without preparation. Pairwise testing showed that without preparation, the marginal adaptation to dentin was significantly worse compared to enamel for HY with both polymerization modes, for DY with SSP. With preparation, no significant differences were found. Cavity preparation may have an influence on differences in marginal quality between enamel and dentin.

Compomers↗
PubMed1999

Bisphenol-A content of resin monomers and related degradation products.

Recently, it was reported that Bisphenol-A (BPA) was released from one fissure sealant (Delton) into saliva causing estrogenic activity in vitro. The aim of this study was to chemically analyze the BPA content of different fissure sealant resin monomers and their release of BPA under hydrolytic conditions. BPA content was first measured in commercially available monomers of bisphenol-A glycidyldimethacrylate (Bis-GMA), bisphenol-A dimethacrylate (Bis-DMA) and bisphenol-A diglycidylether (BADGE). Then, Bis-GMA-monomer and Bis-DMA-monomer in methanol were subjected to pH values of 0 to 11 for 30 minutes at 50 degrees C, to porcine liver esterase, and to pooled saliva for up to 24 hours. The BPA-content was determined by high-performance liquid chromatography (HPLC). Bis-GMA-monomer and BADGE-monomer from one manufacturer did not contain any detectable amounts of BPA (< or = 2 ppm); Bis-DMA and BADGE-monomer from a second manufacturer contained BPA quantities of 4-155 ppm. For Bis-GMA-monomer, no BPA could be detected under any hydrolytic conditions chosen (detection limit: < or = 1%). For Bis-DMA-monomer an increase of BPA was observed at pH 11, resulting in a conversion of approx. 100% Bis-DMA to BPA. When Bis-DMA was subjected to esterase, a conversion of 82.5% resulted after 24 h; saliva led to an 81.4% conversion of Bis-DMA after 24 h. Hence, we conclude that the results reported in the literature may be attributed to the Bis-DMA-content of the fissure sealant tested (Delton). No BPA-release is expected under physiologic conditions from fissure sealants based on Bis-GMA if pure base monomers are used.

Benzhydryl Compounds↗
PubMed1999

Time-related bisphenol-A content and estrogenic activity in saliva samples collected in relation to placement of fissure sealants.

It was recently reported that estrogenic activity was detected in saliva samples collected during 1 h after placement of one fissure sealant (Delton) and this related to Bisphenol-A (BPA) content. The aim of the present study was to determine the time-related BPA content and estrogenic activity in saliva samples collected before and after placement of two fissure sealants each with a different monomer composition. Eight healthy male volunteers with no history of prior placement of fissure sealants or composite resin fillings had four molars sealed with either Delton LC (four people) or Visio-Seal (four people). Base-line saliva samples were collected preexperimentally, in the morning when fasting. Fissure sealants were placed and saliva samples collected immediately, 1 h and 24 hs after placement of the fissure sealant. BPA was found in saliva samples collected immediately after placement of Delton LC (range 0.3-2.8 ppm). No detectable amounts of BPA were determined 1 h and 24 h after Delton treatment (detection limit < or = 0.1 ppm). In base-line samples and in all samples collected from Visio-Seal treated individuals, no BPA was detected. In a recombinant yeast cell assay, significantly increased estrogenic activity was found in saliva samples collected immediately after placement of Delton LC sealant (P < 0.05; ANOVA) whereas no statistically significant estrogenic activity was observed in the remaining groups. In conclusion, minute amounts of BPA, however considerably lower than previously reported, were detected in saliva samples collected immediately after but not 1 and 24 h(s) after placement of Delton LC fissure sealant. BPA was not detected after placement of Visio-Seal fissure sealant.

Adult↗
PubMed1999

Cytotoxic and mutagenic potencies of various root canal filling materials in eukaryotic and prokaryotic cells in vitro.

Cytotoxic and mutagenic effects of root canal filling cements of various chemical composition were determined in vitro. Materials set for 24 h and 1 wk were eluted for 24 h in cell culture medium (cytotoxicity testing) and dimethyl sulfoxide or physiological saline (mutagenicity testing). The differences between cytotoxic potencies of eluates of the endodontic materials on L-929 cells were quantified colorimetrically (MTT test). Eluates of Traitement SPAD were about 5- to 30-fold more toxic than silver-free AH26, Tubli-Seal, CRCS, and Endomethsone N. The rank order of the toxic effects depended on the setting time of mixed materials. Dimethyl sulfoxide and saline eluates of Traitement SPAD, Tubli-Seal, Endomethasone N, CRCS, and Ketac-Endo were not mutagenic in the Ames test. Both eluates of silver-free AH26 set for 24 h were weakly mutagenic in Salmonella typhimurium TA100. Weak mutagenicity of saline eluates of the material was also observed in TA97a and TA102. These results point to the possibility that mixed silver-free AH26 might contain small amounts of two mutagenic substances: bisphenol A diglycidyl ether and formaldehyde.

Administration, Topical↗
PubMed1999

An in vitro pulp chamber with three-dimensional cell cultures.

To better simulate the in vivo situation, a three-dimensional fibroblast cell culture was introduced into an in vitro pulp chamber model. The system was evaluated by testing a series of dental filling materials. After a 24-h exposure with (0.3 or 5 ml/h) and without perfusion of the pulp chamber, the tissues were subjected to a routine MTT assay. Zinc phosphate cement, conventional glass ionomer cements, a silicone impression material, and zinc oxide-eugenol did not influence cell viability, compared with untreated controls; but, a light-curing glass ionomer cement significantly reduced cell survival. Perfusion of the chambers did not significantly influence the results, but perfusion conditions of 5 ml/h lead to a general decrease of cell vitality. The three-dimensional cell culture system in an in vitro pulp chamber seems to be a substantial improvement, because zinc oxide-eugenol does not evoke a cellular reaction (as is the case in vivo), and the test system is sensitive enough to detect other toxicants.

Animals↗
PubMed1998

The mutagenic activity of unpolymerized resin monomers in Salmonella typhimurium and V79 cells.

Dimethacrylate derivatives are used as monomers to polymerize dental composite materials and for a great variety of other industrial resins. Occupational exposure is likely in various ways because of the many areas of methacrylate application. Here, the mutagenicity of the monomers, bisphenol A-diglycidyl dimethacrylate (Bis-GMA), urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEGDMA), Bisphenol A (BPA), glycidyl methacrylate (GMA), methyl methacrylate (MMA), and 2-hydroxyethyl methacrylate (HEMA) was studied in a bacterial (Ames test) and a mammalian gene mutation assay (V79/HPRT assay). Mutagenicity was determined in different Salmonella typhimurium strains (TA97a, TA98, TA100, TA102) and in V79 cells in the presence and in the absence of a metabolically active microsomal fraction from rat liver (S9). No mutagenic effects were observed with Bis-GMA and UDMA, methyl methacrylate, 2-hydroxyethyl methacrylate and bisphenol A. Glycidyl methacrylate (GMA) was mutagenic in a dose-dependent manner in three Salmonella tester strains. The number of mutants was increased by a factor of 2 to 3 with strains TA97a and TA102 in the absence of S9. Moreover, the numbers of mutants induced in S. typhimurium TA100 were about 8-fold higher than in solvent controls. GMA also induced an increase of mutants in V79 cells in the absence of S9. However, GMA was inactivated by microsomal enzymes. Triethylenglycol dimethacrylate (TEGDMA) was not mutagenic in any S. typhimurium. In contrast, the compound induced a dose-dependent rise in mutant frequencies in V79 cell cultures. It is concluded that TEGDMA acted through a clastogenic mechanism which is not detected by Ames tester strains.

Animals↗
PubMed1998

Clinical evaluation of different adhesive systems for restoring teeth with erosion lesions.

This investigation evaluated the performance of a resin-modified glass ionomer, a compomer, and a bonding system/composite combination for the restoration of cervical erosion lesions without cavity preparation. Forty-eight lesions (11 patients) were restored with a bonding agent/composite combination [Prime & Bond 2.1/PrismaTPH (P & B/TPH); DeTrey/Dentsply], a compomer (Dyract; DeTrey/Dentsply), or a light-curing glass ionomer (Fuji II LC; Fuji). The materials were randomly assigned to the patients in triplets. No cavity preparation was performed. The procedures strictly followed the manufacturers' instructions. The restorations were evaluated clinically, using modified USPHS criteria, and by quantitative scanning electron microscope (SEM) analysis, at baseline and 12 months. The clinical data were statistically evaluated with the Pearson chi-square test, the SEM data (criterion gap formation) were analyzed with the Mann-Whitney U-test and error rates method. Clinically, two restorations could not be evaluated. One Dyract restoration failed. With respect to marginal discoloration, recurrent caries and contour, no significant differences could be found between the materials. The surface texture of P & B/TPH and Dyract was significantly better than that of Fuji II LC at baseline and 12 months. Compared to P & B/TPH and Fuji II LC, Dyract revealed a significant decrease in marginal integrity between baseline and 12 months. In SEM analysis, gap formation was determined as follows: baseline, enamel interface: 4% Dyract= 4% Fuji >2% P & B/TPH and dentin interface: 11% Dyract >9% P & B/TPH >2% Fuji; 12 months, enamel interface: 15% Dyract >4% Fuji >3% P & B/TPH and dentin interface: 11% P & B/TPH >6% Fuji >5% Dyract. The error rates method revealed no significant differences, in general, between the three materials with regard to gap formation. In conclusion, the restorations of erosion lesions with different classes of adhesive materials were well retained after 12 months. None of the materials studied revealed superiority over the other materials. All materials revealed shortcomings with respect to either surface texture, marginal integrity or color stability clinically and for all materials gap formation was recorded in the SEM evaluation.

Acetone↗
PubMed1998

Mutagenicity of the root canal sealer AHPlus in the Ames test.

The mutagenic activity of the root canal sealing cement, AHPlus, was tested in a bacterial gene mutation assay (Ames test). The material was mixed according to the manufacturer's instruction and tested immediately after mixing and after a setting time of 24 h at 37 degrees C in a humidified chamber. The set material was powdered and both the freshly mixed and the powdered material were eluted in dimethyl sulfoxide (DMSO) and physiological saline (0.1 g/2 ml) for 24 h at 37 degrees C. Aliquots of serially diluted eluates were then used in the standard plate incorporation assay. The Salmonella typhimurium tester strains TA98 and TA100 were employed to detect the induction of frameshift mutations and base pair substitutions both in the presence and in the absence of a metabolically active microsomal fraction from rat liver (S9 fraction). No mutagenic and no toxic effects were found with physiological saline eluates of the freshly mixed material and of mixed material which was set for 24 h. However, DMSO eluates of the freshly mixed AHPlus were mutagenic in tester strain TA100 in a dose-related manner in the absence of S9. A four- to fivefold increase of the mutation frequencies was induced by 2.5 mg AHPlus per plate compared with the number of spontaneous mutants. The mutagenic effect was completely abolished in the presence of a metabolically active S9 fraction. Also, no mutagenic effects were observed with DMSO eluates of AHPlus set for 24 h. However, the set material was more toxic towards bacteria than the freshly mixed sealer. This difference was indicated by a tenfold lower amount of material necessary to cause complete absence of the background lawn in both S. typhimurium tester strains. Therefore, we conclude that at least two different compounds of AHPlus are biologically active in DMSO eluates to cause mutagenic and toxic effects in S. typhimurium TA100 and TA98.

Animals↗
PubMed1998

Retrospective clinical investigation and survival analysis on ceramic inlays and partial ceramic crowns: results up to 7 years.

This study retrospectively evaluated the clinical performance of 287 all-ceramic restorations placed during routine patient care in the University setting in the past 7 years. All patients (n = 106) with ceramic inlays or partial ceramic crowns (PCC), placed during 1988-1994 (n = 327) by five experienced dentists were asked to take part in a clinical investigation, and 92 patients with 287 restorations (232 inlays, 55 PCC) agreed to do so. The following ceramics were used: 44 (15.3%) Dicor (Dentsply), 126 (43.9%) IPS-Empress (Ivoclar), 82 (28.7%) Mirage II, 33 (11.5%) Cerec-Vita-Mark 1 (Vita), and 2 (0.7%) Duceram LFC (Ducera) restorations. The restorations were placed using the following luting composites: 73 (25.4%) Dual Cure Luting Cement (Optec), 81 (28.3%) Variolink high viscosity (Ivoclar), 32 (11.1%) Microfill Pontic C (Kulzer), 51 (17.8%) Dual Zement (Ivoclar), 40 (13.9%) Dicor Light Activated Cement (Dentsply), and 10 (3.5%) Vita Cerec Duo Cement (Vita). Restorations were evaluated according to the modified USPHS criteria. Kaplan-Meier analysis was used to calculate the probability of survival. Of the 287 restorations 270 (94.2%) were still in function without any need of intervention. Fourteen restorations (4.8%) had failed before starting the clinical investigation, and in three a fracture was found during the investigation. These 17 failed restorations consisted of 14 PCC and 3 ceramic inlays. The results of the clinical investigation revealed 59.2% Alpha-ratings for marginal adaptation. Only one restored tooth showed recurrent caries. The probability of survival (95% confidence interval) for 7 years was 98% (97.99-98.01%) for ceramic inlays and 56% (46-66%) for PCC. Our findings show that ceramic inlays can be regarded as an acceptable alternative to cast gold restorations within the methodological limitations of the present study. For PCC further experience with more recent ceramics is warranted.

Adolescent↗
PubMed1998

Influence of metals on IL-6 release in vitro.

Certain dental alloys have been claimed to cause gingival and periodontal inflammation. However, little information is available on the molecules mediating the mechanism of such an effect. Recently, a three-dimensional cell culture system consisting of human fibroblasts and keratinocytes has been introduced for evaluating the irritancy of cosmetic products, including the analysis of inflammatory mediators. In the present study the influence of pure metals and a high noble dental cast alloy upon cell viability and the synthesis of the proinflammatory mediator interleukin-6 was recorded in this in vitro skin equivalent model. The cultures were exposed to test specimens fabricated from copper, nickel, cobalt, zinc, palladium, tin, indium, a high noble cast alloy and a dental ceramic. Cell vitality was reduced after a 24 h exposure to copper (14-25% of untreated controls), cobalt (60%), zinc (63%), indium (85%), nickel (87%), and the heat treated and not heat treated high noble cast alloy (87%/90%). Dental ceramic, palladium and tin did not influence cell viability. Increased IL-6 levels were observed in cultures exposed to copper (5-19-fold compared to untreated controls), zinc (16-fold), cobalt (12-fold), nickel (10-fold) and palladium (4-fold). Other materials tested produced IL-6 levels comparable to those of untreated controls. Our findings suggest that metal ions are involved in proinflammatory activity at low toxicity and non-toxic levels as assessed by different biological endpoints.

Biocompatible Materials↗
PubMed1998

Quantitative digital subtraction radiography for the determination of small changes in bone thickness: an in vitro study.

OBJECTIVE: The objective of this study was to determine the ability of quantitative digital subtraction radiography to detect small changes in bone thickness adjacent to tooth roots. STUDY DESIGN: A series of cortical or cancellous bone slices with a 50 microm-stepwise increasing thickness were attached to 4 porcine mandible sections covering buccal and interproximal "defect" regions. Standardized radiographs were quantitatively evaluated for radiographic density changes with the use of digital subtraction radiography. Furthermore, all radiographs were conventionally evaluated by 10 clinicians. The Wilcoxon signed-rank test and the Mann-Whitney U test were used for statistical analysis (alpha = 0.05). RESULTS: A high linear correlation was found between the actual thickness of bone slices and radiographic density changes (cortical bone: r2 = 0.89 to 0.99; cancellous bone r2 = 0.61 to 0.86, p < or = 0.001). A certain increase in bone thickness caused a 3 times higher increase in radiographic density for cortical bone than for cancellous bone (p < or = 0.05). The detection limits of digital subtraction radiography were 200 microm for cortical and 500 microm for cancellous bone, whereas the detection limits of conventional radiography were 600 microm and 2850 microm, respectively. CONCLUSIONS: This in vitro study demonstrated a very high correlation between the objective, quantitative assessment of subtle changes in alveolar bone by digital subtraction radiography and the true changes in bone thickness.

Absorptiometry, Photon↗
PubMed1998

The biocompatibility of non-amalgam dental filling materials.

Non-amalgam filling materials may release substances which have been shown to be toxic in cytotoxicity tests and implantation studies. However, results from systemic toxicity tests do not indicate any unacceptable risk to the patient's general health, but data for non-amalgam dental filling materials are scarce in comparison to amalgam. Although estrogen-like effects of one fissure sealant have been claimed, no conclusions can be drawn at present for the patient from these in vitro data because of the limitation of the test methods and materials used. Some components of composite resins/dentin adhesives and a resin-modified glass ionomer cement were mutagenic mainly in in vitro tests. Due to the limitations of the test systems and the comparatively high concentrations needed to elicit the reactions, no unacceptable risk can yet be derived from those data for the patient. However, a no-touch technique is recommended for the dental personnel. As with amalgam, local reactions of the pulp are not expected with alternative filling materials, if the pulp tissue is not exposed and if bacterial penetration is avoided. The latter requirement is still difficult to fulfill, especially for composite resin systems and related materials in posterior teeth situations. Slight gingival reactions to alternative filling materials and to amalgams are mainly attributed to plaque accumulation. From all these data it can be concluded that, for the time being, it is not possible to rank dental filling materials in respect to their biocompatibility, and it is evident that biocompatibility must be considered to the same extent for both amalgams and commonly used or recommended alternative filling materials.

Adhesives↗
PubMed1998

Healing response to non-surgical periodontal therapy in patients with diabetes mellitus: clinical, microbiological, and immunologic results.

The aim of the present study was to monitor clinical, microbiological, medical, and immunological effects of non-surgical periodontal therapy in diabetics and healthy controls. 20 IDDM (insulin dependent, n = 7) or NIDDM (non-insulin dependent, n = 13) diabetic patients (median duration 11.5 years, range of HbA1C: 4.4-10.6%) with moderate to advanced periodontal disease and 20 matched healthy control patients, were subjected to supragingival pretreatment and subsequent subgingival therapy. Periodontal examinations (API, PBI, BOP, PPD, PAL), microbiological examinations (culture), medical routine examinations, and immunological examinations (oxidative burst response of PMNs to TNF-alpha and FMLP) were performed at baseline, 2 weeks after supragingival, and 4 months after subgingival therapy. 4 months after completion of non-surgical therapy, the following compared to baseline significant (p < or = 0.05) changes (delta) of clinical parameters (median) were found in diabetic patients versus control patients: deltaAPI (30.4% versus 36.3%), deltaPBI (22.9% versus 24.2%), deltaBOP (39.5% versus 46.9%). The median % per patient of pockets with PPD > or = 4 mm decreased from 41.9% to 28.3% in diabetics, and from 41.6% to 31.8% in controls. Microbiologically, similar reductions of periopathogenic bacteria were found in diabetics and controls. Neither periodontal data nor the oxidative burst response of PMNs showed any significant difference (p > 0.05) between diabetics and control patients. In this study, periodontal therapy had no significant influence on medical data of diabetics. In conclusion, this study indicates that metabolically well-controlled diabetics might respond to non-surgical periodontal therapy as well as healthy control patients.

Adult↗
PubMed1998

GTR therapy of intrabony defects using 2 different bioresorbable membranes: 12-month results.

This prospective split-mouth study was designed to compare the clinical and radiographic healing results in intrabony periodontal defects 12 months after GTR therapy with 2 different bioresorbable barriers. The study comprised 25 healthy patients with one pair of contralaterally located intrabony defects with a probing pocket depth of > or = 6 mm and radiographic evidence of angular bone loss of > or = 4 mm. The 2 defects of each patient were randomized for treatment either with polylactic acid (PLA) membranes or with polyglactin-910 (PG-910) membranes. The patients received systemic doxycycline (100 mg/d) for 11 days postoperatively. One blinded examiner recorded the following clinical parameters using a pressure calibrated probe at baseline and after 12 months: papillary bleeding index (PBI), gingival recession (REC), probing pocket depth (PPD), and probing attachment level (PAL). The vertical relative attachment gain (V-rAG) was calculated as a % of the PAL gain related to the maximum possible attachment gain (expressed by the intraoperatively measured depth of the osseous defect). Geometrically standardized intraoral radiographs were quantitatively evaluated for bone changes (density, area) in the defect region using digital subtraction radiography (DSR). Clinical and radiographic data were statistically analyzed using the Wilcoxon-signed-rank test (alpha=0.05). Postoperative membrane exposures occurred in 9 PLA and 13 PG-910 treated sites. After 12 months of healing, both barrier types provided significant PPD reductions and PAL gain [median (25/75 percentile)]: deltaPPD [PLA: 3.0 (2.0/4.0) mm; PG-910: 3.0 (2.0/4.5) mm]; deltaPAL [PLA: 3.0 (2.5/4.0) mm; PG-910: 2.0 (1.0/4.0) mm]. V-rAG amounted to 60% in PLA sites and 54% in PG-910 sites. DSR revealed significant bone density gain after 12 months. 58.3% of the initial defect area in PLA sites and 54.0% of the initial defect area in PG-910 sites showed bone density gain. Neither clinical nor radiographic data revealed any significant difference between the 2 barrier types after 12 months. In conclusion, this 12-month study demonstrated that PLA and PG-910 membranes provided similar favorable regeneration results in deep intrabony periodontal defects.

Adult↗
PubMed1998

Accuracy of quantitative digital subtraction radiography for determining changes in calcium mass in mandibular bone: an in vitro study.

The aim of this in vitro study was to determine the accuracy of digital subtraction radiography (DSR) to detect small changes in calcium mass in alveolar bone adjacent to tooth roots. In each of 4 dried porcine mandible segments, one interproximal and one buccal "defect" region was defined adjacent to a premolar root. A series of cortical and cancellous bone slices with a 50 microns--stepwise increasing thickness (0-5000 microns) were attached to the mandible segments covering the respective "defect" region. Standardized radiographs were quantitatively assessed for density changes using DSR. After dissolving each bone slice in hydrochloric acid, its calcium concentration was photometrically determined. For each bone slice, the mean calcium mass covering a single pixel of the subtraction image was calculated. The Wilcoxon signed-rank test and the Mann-Whitney U-test were used for statistical analysis (alpha = 0.05). A strong linear correlation (r2 = 0.86-1.00; p < or = 0.001) was found between the thickness of the bone slices and their calcium mass. Cortical bone showed a 3.5 times higher mean calcium mass/pixel than cancellous bone. Furthermore, a strong linear correlation (r2 = 0.63-1.00; p < or = 0.001) was found between the mean calcium mass per image pixel and the radiographic density changes. Neither the bone type nor the "defect" localization had a significant influence on radiographic density changes caused by changes in calcium mass. A change in mean calcium mass per image pixel of 0.1-0.15 mg was necessary to be detected by DSR. In conclusion, this study revealed a high accuracy of DSR to detect small changes in calcium mass in alveolar cortical and cancellous bone.

Alveolar Bone Loss↗
PubMed1998

Developmental enamel defects in children with different fluoride supplementation--a follow-up study.

The intake of fluorides with water, food, dental fluoride preparations, or in particular fluoride supplements, such as NaF tablets, may lead to dental fluorosis. In the present study conducted in a nonfluoridated area in Germany, developmental enamel defects were examined using the Modified Developmental Defects of Enamel Index (Mod DDE Index), which subdivides enamel defects into the categories demarcated (Mod DDE score 1) and diffuse (Mod DDE score 2) opacities and hypoplasia (Mod DDE score 3). 158 children, between 8.5 and 10 years old, were assigned to three examination groups, defined by three different fluoride tablet programs. The children in all three examination groups, F1, F2, and F3, had received 0.25 mg F-/day up to the age of 2 years, F1 and F3 from birth on, F2 beginning with the 7th month of life. F1 and F2 received 0.5 mg F-/day during the 3rd and 0.75 mg F-/day during the 4th and 5th year of life. For F3, beginning with the 3rd year of life, no further recommendations were made. 158 sociodemographically matched children living in a neighboring town served as controls and did not take part in any structured fluoride supplementation program. The proportions of children with Mod DDE scores 1, 2, or 3 at least in one index tooth were significantly higher in the examination groups (40%) than in the control group (20%). Also, the proportions of children with Mod DDE score 2 at least in one index tooth were significantly higher in the examination groups (18%) than in the control group (8%). The proportions of children with Mod DDE score 1 at least in one index tooth were 25% in the examination groups and 17% in the control group. No Mod DDE score 3 was found. Not more than 5% of the children in each group had 50% of their teeth with Mod DDE score 1, 2, or 3. The proportions of teeth per child with Mod DDE score 2 were significantly higher in the examination group than in the control group. While uncontrolled variables cannot be excluded, the observed differences between the experimental and control groups may be attributed to the ingestion of fluoride tablets in the experimental group.

Age Factors↗
PubMed1998

Cytotoxicity of dental alloy extracts and corresponding metal salt solutions.

Adverse tissue reactions of the gingiva and the periodontium close to dental cast alloys may be caused by the effects of released metal elements. Tissue reactions depend upon the amounts of elements available which are a function of corrosion rates. Since pH values of standard corrosion solutions are as low as 2.3, such extracts are a priori not biocompatible. In the present study, elements released from dental cast alloys into cell-culture media were determined, and the cytotoxicity of these medium extracts was compared with the effectiveness of metal salt solutions prepared according to the metal elements found in extracts. The elements Ag, Cu, Ni, and Zn were detected in extracts of dental alloys and copper (positive control) by inductively coupled plasma atomic emission spectrometry (ICP-AES). Medium extracts of dental alloys were non-toxic in mouse fibroblasts (L929 cells). However, the amounts of elements found in these extracts were weakly cytotoxic when tested as salt solutions prepared from chloride (Cu2+, Zn2+, Ni2+) or sulfate (Ag1+) salts. When the test specimens were heat-treated before extraction, extracts were clearly cytotoxic in a dose-related manner. Again, the amounts of elements that caused 50% cell death (TC50) were slightly lower in corresponding salt solutions than in extracts. In general, cytotoxicity of medium extracts consistently proved to be slightly less than that of the corresponding salt solutions, probably due to the limitations of the chemical analysis of extracts. This should be taken into account if salt solutions are used instead of the medium extract.

Animals↗