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Biomedical subjects

Andrej M Kielbassa

Publications and source records attributed to Andrej M Kielbassa.

At least 19 recordsLinked to original sources
PubMed2006

Surface microhardness of enamel after different home bleaching procedures.

OBJECTIVES: The purpose of this study was to evaluate the influence of different home bleaching procedures on surface microhardness of human enamel. METHODS: Among eight groups 192 incisors were distributed. The facial surface of each incisor was polished and baseline hardness of enamel (m0; Knoop) was assessed with a load of 1N for 30s. Subsequently, the enamel was treated for 14 days with the bleaching agent: groups 1, 2 and 4 Viva Style Paint on, 8% carbamide peroxide (CP) 1x20min, 2x20min and 2x5min; group 3 Colgate Simply White, 5.9% hydrogen peroxide (HP), 2x30min; group 5 Viva Style 10% CP 1x1h; group 6 Blend-a-med White Strips, 5.9% HP 2x30min; group 7 Odol-med3 Beauty-Kur, sodium chlorite 2x10min; group 8 control, running water 1x1h. Hardness was reassessed after the last bleaching treatment (m1) and after 6 weeks storage in artificial saliva (m2). RESULTS: Changes in microhardness were as follows (m0-m1): (1) -2.3 (+/-20.3); (2) -8.9 (+/-27.2); (3) 63.4 (+/-56.3); (4) 9.6 (+/-30.1); (5) 12.8 (+/-62.6); (6) 92.2 (+/-50.2); (7) 158.4 (+/-59.7); (8) 10.6 (+/-38.5). Statistical analysis showed that hardness values were significantly (p< or =0.0005; Wilcoxon test) reduced in groups 3, 6, and 7 (m1) and in group 7 (m2). SIGNIFICANCE: Both type of bleaching agent and concentration have a significant influence on the microhardness of enamel. The most critical bleaching agent seems to be the one containing sodium chlorite in combination with citric acid.

Carbamide Peroxide↗
PubMed2006

Penetration coefficients of commercially available and experimental composites intended to infiltrate enamel carious lesions.

OBJECTIVES: Arresting of enamel lesions by infiltration with light curing composite resins might be a treatment alternative of future micro-invasive dentistry. So far only commercially available adhesives and fissure sealants have been used to infiltrate enamel lesions. Since these products have been optimized for adhesive purposes, the aim of this study was to develop optimized resins for the infiltration of enamel lesions and to measure their physical properties. METHODS: The penetration coefficients (PCs) of five adhesives and a fissure sealant as well as 66 experimental composite resins were determined. To establish the resins' PCs the viscosities, surface tensions, and contact angles to bovine enamel were measured. RESULTS: For the commercially available products PCs from 4.0 to 278.9 cm/s were measured. Four of these materials showed a good correlation with penetration depths obtained in a previous study. Experimental composites showed PCs from 0.2 to 474.9 cm/s. The addition of ethanol significantly increased the PCs due to a decrease of viscosity and contact angle. Highest PCs were found for mixtures containing TEGDMA, HEMA and 20% ethanol. SIGNIFICANCE: The knowledge about the PC of resin composites seems to be useful for the development of new materials optimized to infiltrate enamel lesions.

Animals↗
PubMed2006

Evaluation of cavitations in proximal caries lesions at various magnification levels in vitro.

OBJECTIVES: The aim of this study was to evaluate the cavitation rate of proximal caries using different magnification aids in vitro. METHODS: Radiographs of 285 extracted teeth were taken and the proximal surfaces were graded to the criteria R0 (no radiolucency), R1 (radiolucency confined to the outer half of enamel), R2 (inner half of enamel) and R3 (outer half of dentin). Subsequently, the proximal surfaces were checked for the presence of cavitations with the naked eye (NE), and by using 4.3 x magnification eyeglasses (ME), a stereo microscope (SM, 10x), or a scanning electron microscope (SEM, up to 2000 x magnification). RESULTS: In surfaces with R3 caries, cavitations were visible in 56 of 59 cases with the naked eye. When using SEM, all surfaces revealed cavitations (100%). Regarding the surfaces with R2 lesion, 36 of 46 cases showed cavitations (NE); the corresponding values were 39/46 (ME), 41/46 (SM), and 46/46 (SEM); in the latter, in most cases deep defects could be observed. With regard to R1 lesions, 36/60 (NE), 43/60 (ME), 45/60 (SM), and 58/60 (SEM) cases revealed cavitations. A breakdown of radiographically sound surfaces (R0) was present in some 10% of the examined surfaces (24/261, NE; 33/261, SEM). CONCLUSIONS: Cavitations (defined as breakdown of the surface) are present in significantly more cases than previously reported. This might be an explanation why even small radiolucencies tend to progress, albeit slowly. Thus, close follow-ups should strongly be recommended when considering a preventive treatment regimen with small radiolucencies.

Dental Caries↗
PubMed2006

Linseed based saliva substitutes and their effect on mineral dissolution of predemineralized bovine dentin in vitro.

OBJECTIVES: Polymers used in saliva substitutes might inhibit remineralization. The present study evaluated the effects of various calcium, phosphate, and fluoride concentrations of linseed based solutions on the mineral loss of predemineralized bovine dentin in vitro. METHODS: Dentin specimens were prepared, embedded and polished. The specimens were demineralized (pH 5.6; 6 d; 37 degrees C) and half of each sample was covered with nail varnish. Subsequently, the specimens (n=10) were exposed to 14 linseed based solutions (calcium 0-1.1 mM; phosphate 0-7.7 mM, fluoride 0-0.03 mM) at pH 5.5 and 6.5 as well as to Salinum for 14 days (37 degrees C). The differences in mineral loss (DeltaDeltaZ) between the values prior to and after storage in the solutions were evaluated from microradiographs of thin sections. RESULTS: After the exposure to the various solutions decreased mineral contents compared to those after demineralization could be observed (p<0.05; paired t-test) whereas for the specimens stored in solution with the highest calcium and phosphate concentration no significant change in mineral loss could be evaluated (p>0.05). Salinum induced a significantly greater mineral loss compared to the equivalent saturated solution (p<0.05; ANOVA, Bonferroni). The general linear model revealed a significant dependency for DeltaDeltaZ on 'phosphate' (p=0.000) and 'fluoride' (p=0.001), but not on 'calcium' (p=0.397) and 'pH' (p=0.368). CONCLUSIONS: The addition of calcium, phosphates, and fluorides seems to have a positive effect on the remineralizing qualities of linseed based saliva substitutes.

Analysis of Variance↗
PubMed2006

Tissue responses to an experimental calcium phosphate cement and mineral trioxide aggregate as materials for furcation perforation repair: a histological study in dogs.

The aim was to evaluate histologically the inflammatory reactions and tissue responses to an experimental tricalcium phosphate cement (TCP) and mineral trioxide aggregate (MTA) when used as repair materials in furcation perforations in dogs. Perforations were performed in 24 mandibular premolars of six anaesthetised dogs and filled either with ProRoot MTA (grey) or TCP. The root canals were subsequently shaped and filled, and the access cavities were closed with a bonded composite resin. The animals were killed at 12 weeks. After radiological examination, the teeth and surrounding structures were processed for light microscopy. Concerning the grades of inflammation, MTA exhibited significantly better results than TCP (chi-square test according to Pearson). No furcation was free of inflammatory cells. Mild inflammation was observed in nine of twelve cases with MTA and only twice in those with TCP. No significant differences were revealed between MTA and TCP in terms of bone reorganization or deposition of fibrous connective tissue (Mantel-Haenszel chi-square test). The grade of radiological examination corresponded with the grade of inflammation or differed by only one grade plus or minus. Perforations located in the furcation of teeth remain an endodontic and a periodontal problem with an uncertain prognosis, in spite of the promising modern materials applied.

Aluminum Compounds↗
PubMed2006

In vitro evaluation of push-out bond strengths of various luting agents to tooth-colored posts.

STATEMENT OF PROBLEM: Different compositions of tooth-colored posts may influence the bonding capacity of various luting agents to these posts. An appropriate understanding of these interactions is presently unavailable. PURPOSE: This study initially evaluated the effects of various pretreatment procedures on bond strengths to zirconium-oxide posts using a phosphate-methacrylate resin luting agent. Following that investigation, the bond strengths of various luting agents to tribochemically coated glass-fiber-reinforced composite (FRC) resin and zirconium-oxide posts were investigated. MATERIAL AND METHODS: Two hundred zirconium-oxide posts (CosmoPost) divided into 10 groups (n=20) were luted into artificial post spaces prepared with drills provided by the manufacturer. In 4 groups the posts were luted with phosphate-methacrylate resin agent (Panavia F) after receiving one of the following pretreatment procedures: no treatment (control); airborne-particle abrasion; silica coating and silanization with an intraoral airborne-particle-abrasion device (CoJet); or silica coating and silanization with a laboratory airborne-particle-abrasion device in combination with airborne-particle abrasion (Rocatec). The other zirconium-oxide posts in the 6 remaining groups were silica coated (CoJet), silanated, and luted with 1 of 6 different luting agents (Multilink, Variolink, PermaFlo DC, RelyX Unicem, Clearfil Core, and Ketac Cem). Additionally, 60 FRC posts (FRC Postec) were silica coated (CoJet), silanated, and luted with 1 of the 6 resin luting agents (Panavia F, Multilink, Variolink, PermaFlo DC, RelyX, and Clearfil Core). Push-out tests were performed to evaluate the bond strengths between luting agents and posts. Qualitative scanning electron microscopy (SEM) analyses were performed to evaluate the effects of the pretreatment procedures on the surface of the zirconium-oxide posts. Data were analyzed using analysis of variance (ANOVA) followed by the post hoc Tukey B test (alpha=.05). RESULTS: Bond strengths to the posts were significantly affected by the type of luting agent and the type of post (P<.001; 2-way ANOVA). Bond strengths of all luting agents to the FRC posts were significantly higher than to the zirconium-oxide posts (P<.01), except for Multilink and PermaFlo DC, which demonstrated higher bond strength values to the zirconium-oxide posts (P<.001). Pretreatment procedures significantly increased the bond strength of Panavia F to the zirconium-oxide posts (P<.05). SEM analyses revealed distinctive irregularities on the surface of the pretreated zirconium-oxide posts compared to the untreated posts. CONCLUSION: Bond strengths of luting agents to tooth-colored posts are significantly affected by the type of luting agent and the type of post. All investigated pretreatment procedures of zirconium-oxide posts significantly increased the bond strength of Panavia F.

Analysis of Variance↗
PubMed2006

Radiation-related damage to dentition.

Because of typical tissue reactions to ionising radiation, radiotherapy in the head and neck region usually results in complex oral complications affecting the salivary glands, oral mucosa, bone, masticatory musculature, and dentition. When the oral cavity and salivary glands are exposed to high doses of radiation, clinical consequences including hyposalivation, mucositis, taste loss, trismus, and osteoradionecrosis should be regarded as the most common side-effects. Mucositis and taste loss are reversible consequences, usually subsiding early post-irradiation, whereas hyposalivation is commonly irreversible. Additionally, the risk of rampant tooth decay with its sudden onset and osteonecrosis is a lifelong threat. Thus, early, active participation of the dental profession in the development of preventive and therapeutic strategies, and in the education and rehabilitation of patients is paramount in consideration of quality-of-life issues during and after radiotherapy. This Review focuses on the multifactorial causes of so-called radiation caries and presents possible treatment strategies to avoid loss of dentition.

Dental Caries↗
PubMed2006

Clinical monitoring of the effect of fluorides on long-existing white spot lesions.

The aim of this examiner-blind, clinical monitoring was to observe long-existing white spot lesions over a period of 6 months and to evaluate the effectiveness of fluoridated toothpastes on these lesions. Thirty-nine subjects with at least one lesion participated in the study. They were randomly divided into two groups (n=20 and n=19) and instructed to brush their teeth either with toothpaste containing sodium fluoride (1500 ppm) (group 1) or with toothpaste containing amine fluoride (1250 ppm) (group 2). Lesions were measured with quantitative light-induced fluorescence (QLF) and alterations were quantified by DeltaQ as fluorescence loss integrated over the lesion area (% x mm(2)). All QLF images were taken by one examiner at baseline (DeltaQ1) and follow-up visits after 2, 4, 6, 8, 10, and 12 weeks, and after 4, 5, and 6 months (DeltaQ10). The results showed a slight but not significant progression of DeltaQ (% x mm(2)) in group 1 ((p>0.05; t-test), DeltaQ1 -20.31 (+/-41.06); DeltaQ10 -26.2 (+/-47.69)) and in group 2 ((p>0.05), DeltaQ1 -22.28 (+/-43.86); DeltaQ10 -26.39 (+/-46.4)). The results indicated no significant differences regarding the influence of the fluoridated toothpastes (p>0.05). It can be concluded that within 6?months the long-existing white spot lesions are stable concerning fluorescence loss over the lesion area. Moreover, fluoride does not seem to have any effect on long-existing white spot lesions.

Adolescent↗
PubMed2006

Shear bond strengths of different substrates bonded to lithium disilicate ceramics.

The aim of this study was to evaluate the shear bond strengths of pre- and untreated resin core materials to lithium disilicate ceramics. Bond strengths to dental hard tissues served as controls. Ceramic cubes (IPS-Empress II) were luted either with a one-step (Variolink II/Excite DSC) or multiple-step total etching bonding system (Tetric Flow/Syntac Classic) to ground surfaces of human enamel, dentin, and resin core materials (Clearfil Core, Multicore). Resin core materials were additionally pretreated with hydrofluoric acid (HF) or were silica-coated (CoJet System). Shear bond strengths were determined after 24-hour water storage (n=10) and thermocycling (TC) (n=10; 2000 cycles, 5-55 degrees C, 30 seconds). Bond strengths to enamel, dentin, and silica-coated composites were significantly higher compared to untreated and HF-pretreated composites (p<0.05; Tukey B). Indeed, silica coating of the composite resins significantly increased the bond strength to ceramics (p<0.05; Tukey B). Due to the lower bond strength values of ceramics to untreated composite resins (as compared to enamel and dentin), any indication for a resin core build-up prior to the preparation of a ceramic restoration should be considered carefully.

Acrylic Resins↗
PubMed2006

Coronal leakage of calcium phosphate-based root canal sealers compared with usual sealers.

The purpose of the present study was to compare two experimental calcium phosphate-based sealers with AH Plus, Sealapex, Ketac-Endo and Hermetic with regard to coronal seal. Two standardized artificial canals were prepared in each of 120 blocks of bovine root dentin. The blocks were divided into six groups. All of the 40 canals of each group were filled with gutta-percha and either AH Plus, Hermetic, Ketac-Endo, Sealapex or two different experimental sealers. One canal of one block was filled with gutta-percha and sealer using lateral condensation, whilst the other canal was obturated using Thermafil. The roots were immersed in black ink and thereafter cleared. Maximum linear dye penetration was measured coronally. Statistical analysis was performed by means of the Kruskal-Wallis test for the global null hypothesis and the closed test procedure for pairwise comparisons. With lateral condensation, experimental sealer I was comparable with AH Plus and Hermetic but showed significantly higher penetration depths than Ketac-Endo and Sealapex. Using Thermafil, more leakage was found for experimental sealer I than for AH Plus, Ketac-Endo and Sealapex. Using both techniques, leakage of experimental sealer II did not differ significantly from leakage of AH Plus, Ketac-Endo and Sealapex. Due to the low leakage of experimental sealer II in the present study, further evaluations such as bacterial penetration or fluid filtration should follow.

Animals↗
PubMed2006

[A quadrant-design trial of four therapeutic modalities in chronic moderate periodontitis].

UNLABELLED: This randomized clinical study (blind and controlled) compared the effectiveness of an ER:YAG laser (combined with a calculus detection system using fluorescence induced by diode laser radiation for use in non-surgical periodontal therapy) as well as sonic and ultrasonic scalers and scaling and root planning with hand instruments to each other. 72 patients suffering from moderate chronic periodontitis (based on a probing depth of 4 mm or more of at least one tooth in each quadrant) were treated using either an Er:YAG-Laser (KEY 3, KaVo), a piezo-electric ultrasonic system (Piezon Master 400, EMS), a sonic scaler (Sonicflex 2003 L, KaVo), or Gracey Mini-five curettes (Hu Friedy) (control). These four kinds of treatment were randomized and grouped into quadrants. Oral health indicators, probing depths (PD) and clinical attachment levels were examined before commencement of the hygiene phase as well as three months after by a blind, calibrated examination. Within the study period, the mean PD (+/- SE) of the control group fell from 4.40 (0.03) mm to 3.08 (0.03) mm; for the laser group, the reduction was slightly greater, falling from 4.47 (0.04) mm to 3.08 (0.03). In comparison, values for the ultrasonic group were 4.39 (0.04) mm in the pre-study examination and 3.09 (0.04) after treatment; in the sonic group, the values were 4.40 (0.03) mm pre-study and 3.07 (0.03) mm post-study. Within the control group, the mean CAL (+/- SE) decreased from 4.95 (0.07) mm to 3.92 (0.07) mm. Within the laser group, the reduction was more distinct, falling from 5.05 (0.07) mm to 3.88 (0.07) mm. In the ultrasonic group, the median CAL decreased from 5.02 (0.08) mm to 3.88 (0.08) mm and from 4.95 (0.07) mm to 3.84 (0.08) mm within the sonic group. From the date of treatment until the third month thereafter, all of the clinical parameters were shown to be statistically significant (p < 0.0001; GEE). Use of the laser led to a much greater reduction in PD levels (p = 0.0021; GEE) than in the ultrasonic group and demonstrated a higher increase in CAL (p = 0.0010; GEE) relative to the manual methods. CONCLUSION: All four methods of treatment lead to a clinically comparable outcome.

Adult↗
PubMed2006

Bond strengths of resin cements to fiber-reinforced composite posts.

PURPOSE: To evaluate the bond strengths of six different luting cements to fiber-reinforced composite (FRC) posts after various pre-treatment procedures. METHODS: 180 FRC posts were divided into three groups (n=60) and received the following surface treatments. Group 1: untreated control; Group 2: silane treatment; Group 3: CoJet treatment. The posts of each group were fixed with six different luting cements. Push-out tests were performed to determine the bond strengths between the cements and the fiber posts. RESULTS: The observed bond strengths (MPa) of the different resin cements to the posts were significantly affected by the type of cement (P< 0.001), but not by the pre-treatment chosen (P> 0.05; 2-way-ANOVA). Without consideration of the pre-treatment procedures, Clearfil showed the highest bond strengths, followed by Panavia F and RelyX, whereas Multilink, Variolink and PermaFlo showed significantly lower bond strength values (P< 0.05; Tukey's B).

Analysis of Variance↗
PubMed2006

Randomized clinical trial on the efficacy of 2 over-the-counter whitening systems.

OBJECTIVE: The purpose of this clinical trial was to evaluate the efficacy of 2 over-the-counter whitening systems: a liquid whitening gel (5.9% hydrogen peroxide, twice a day for 15 minutes), and a sodium chlorite-based whitening gel applied in a tray system (10 minutes twice a day). METHOD AND MATERIALS: Sixty volunteers (minimum shade A3 on 1 maxillary tooth) were selected to participate in this single-blind (examiner-blinded), single-center, 2-group trial. The subjects were randomly divided into 2 groups (n = 30 each) and instructed to bleach their teeth for 2 weeks. Efficacy was measured using the Vita Classical shade guide and a spectrophotometer at baseline, as well as after 2 weeks and 6 months. RESULTS: For the subjectively measured tooth shades, improvement for maxillary canines was 2.03 +/- 3.67 tooth shades in group 1 and 1.08 +/- 2.19 tooth shades in group 2 after 2 weeks; the maxillary incisors revealed a tooth shade improvement of 0.83 +/- 1.71 tabs in group 1 and 0.73 +/- 2.22 tabs in group 2 (P < .05, except maxillary incisors in group 2; t test). Objectively measured tooth shade scores revealed a change of 0 +/- 0.25 tooth shade tabs (P > .05). CONCLUSIONS: The bleaching gel containing hydrogen peroxide achieved a slight improvement, and the sodium chlorite-based bleaching gel achieved only a small tooth color improvement. Moreover, subjectively and objectively measured tooth shades revealed considerably different results in the clinical situation.

Adult↗
PubMed2006

[The role of COX-2 in dentistry. Past or future?].

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used to inhibit cyclooxygenase (COX) activity within the scope of pain and inflammation therapy. Although these pharmaceuticals are effective in the treatment of pain and inflammation, their routine and long-term administration is limited due to their side effects (e.g., gastrointestinal and renal complications, inhibition of platelet aggregation). COX isoenzymes are of great scientific interest, since these drugs are the main targets of NSAIDs. While the inhibition of COX-2 is related to anti-inflammatory effects, the use of COX-1 might be associated with adverse reactions. Therefore, new generation selective COX-2 inhibitors have been developed to reduce possible side effects. Recently, these new anti-inflammatory drugs have been used for the treatment of various inflammatory diseases. At the same time, COX-2 inhibitors appear promising for control of dental pain and for supportive treatment of inflammatory periodontal diseases. The superior analgesic and sustained efficacy, along with the reduced side effects of COX-2 inhibitors (compared to NSAIDs) have been revealed in numerous clinical studies, in particular after oral surgery. Moreover, NSAIDs have been used for periodontal therapy, and evidence from animal experiments and clinical trials has documented that NSAIDs seem to stabilize periodontal conditions by reducing the rate of alveolar bone resorption. This article reviews the use of NSAIDs and COX-2 inhibitors in dental medicine for pain control and periodontal therapy.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2006

Effect of polymers used in saliva substitutes on demineralized bovine enamel and dentin.

PURPOSE: To evaluate the effects of porcine mucin- and carboxymethylcellulose-based (CMC) solutions on the inhibition of demineralization of pre-demineralized bovine enamel and dentin in vitro. Additionally the sugar substitutes sorbit or xylit were added to the various solutions. METHODS: 54 enamel and dentin samples were prepared from 14 freshly extracted permanent bovine central incisors. The samples were demineralized (pH 5.0 for enamel and pH 5.5 for dentin; 14 days) and subsequently exposed to either mucin- or CMC-based solutions combined with xylit and sorbit at pH 5.5. After in vitro exposure, the specimens were cut perpendicular to the enamel/dentin surface and the sections were ground (4000 grit) to a uniform thickness (100 microm). Mineral loss and lesion depths were evaluated from microradiographs with a dedicated software package (TMR 2.0.27.2). RESULTS: For both dental hard tissues, storage in the mucin-containing solutions resulted in significantly higher lesion depths (deltaLD), but lower mineral loss values (deltadeltaZ) compared to the CMC-containing solutions (P< 0.05; 2-way ANOVA). For the dentin specimens, significant differences in deltadeltaZ were observed between sorbit and xylit (P< 0.05; 2-way ANOVA). The mineral loss and lesion depths of the enamel specimens did not differ significantly after storage in the various solutions (P> 0.05; Bonferroni post hoc test). For the dentin specimens stored in the solution containing mucin/xylit the mineral loss was significantly decreased compared to the other mucin groups as well as to the CMC/xylit solution (P< 0.05; Bonferroni post hoc test).

Analysis of Variance↗
PubMed2006

Randomized clinical study on the efficacy of a new lacquer for dentine hypersensitivity.

The purpose of this randomized, clinical, double-blind short-term trial was to evaluate the efficacy of a new lacquer containing a new component (phosphonic acid methacrylate) designed for treating dentine hypersensitivity. Eighty-eight patients participated in this study. At the first visit one tooth was treated with the lacquer (1), while another tooth was treated with a placebo (2). Sensitivity levels were determined before treatment as well as after one week. An air blast stimulus and a visual analogue scale were used for evaluation. At baseline, the mean hypersensitivity score of group 1 (53.2+/-26.3) was comparable to the mean hypersensitivity score of the teeth in group 2 (53.3+/-24.4). After one week, a significant reduction of the mean hypersensitivity scores (p <0.001; t-test) was revealed in group 1 (25.8 +/-26.6) as well as in group 2 (26.4+/-25.3). The difference between the two treatment groups was not significant (p = 0.7). There is either no difference between the two treatment modalities or the placebo response and/or the time effect was so strong that the treatment efficacy of the new lacquer was hidden by these effects.

Adult↗