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Dive into the research topics where Kerstin Bitter is active.

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Featured researches published by Kerstin Bitter.


European Journal of Oral Sciences | 2009

Morphological and bond strength evaluation of different resin cements to root dentin

Kerstin Bitter; Sebastian Paris; Cindy Pfuertner; Konrad Neumann; Andrej M. Kielbassa

This study correlated the morphological characteristics with the bond strengths of various resin cements used for bonding fiber posts to root canal dentin. Fifty glass-fiber posts (FRC Postec Plus) were luted into the root canals of extracted human anterior teeth using five resin cements (n = 10): Panavia F 2.0, PermaFlo DC, Variolink II, RelyX Unicem, and Clearfil Core. Before insertion of the post, the adhesive systems were labeled with fluorescein and the resin cement was labeled with rhodamine isothiocyanate. The roots were sectioned into three slices (of 2 mm thickness), and each slice was analyzed using confocal laser scanning microscopy in dual fluorescence mode to determine hybrid layer thickness, the number of resin tags, and the number of broken tags. Bond strengths were measured using a micro push-out test. Bond strengths to root canal dentin, as well as the morphological characteristics, were significantly affected by the materials. However, these factors did not correlate. The self-adhesive resin cement, which showed the formation of a hybrid layer and resin tags only sporadically, had the highest bond strengths. These results indicate that chemical interactions between the adhesive cement and hydroxyapatite may be more crucial for root dentin bonding than the ability of the same material to hybridize dentin.


Journal of Endodontics | 2009

Randomized Clinical Trial Comparing the Effects of Post Placement on Failure Rate of Postendodontic Restorations: Preliminary Results of a Mean Period of 32 Months

Kerstin Bitter; Jörn Noetzel; Oliver Stamm; Juliane Vaudt; Hendrik Meyer-Lueckel; Konrad Neumann; Andrej M. Kielbassa

INTRODUCTION The aim of this randomized clinical trial was to assess whether the placement of a fiber post (DT Light Post) (DT) and the amount of residual coronal dentin affect the time to failure of single-unit postendodontic restorations. METHODS Ninety patients providing 120 teeth were selected. Three groups (n = 40) were defined on the basis of the amount of residual coronal dentin: 2-walls group, 2 or more coronal walls; 1-wall group, 1 coronal wall; no-wall group, no wall exceeding 2 mm above the gingival level. Within each group teeth were randomized and allocated to 2 intervention groups (n = 20), including subgroups no post (no root canal retention) and subgroups post (placement of DT). RESULTS After a mean observation period of 32.4 (13.7) months in subgroups no post, the failure rates were 10%, whereas in subgroups post, failure rates of 7% were observed (P = .318). In no-wall group post placement significantly affected the time to failure of total restorations (P = .029, log-rank test). Teeth without post retention revealed a significantly higher failure rate (31%) compared with teeth restored with post retention (7%). CONCLUSIONS Within the observation time of the present study, fiber post placement was efficacious to reduce failures of postendodontic restorations only with teeth that exhibited no coronal walls. Post insertion for teeth showing a minor substance loss should be critically reconsidered.


Caries Research | 2012

Randomized controlled clinical trial on proximal caries infiltration: three-year follow-up

Hendrik Meyer-Lueckel; Kerstin Bitter; Sebastian Paris

We report the 3-year efficacy of resin infiltration (Icon, pre-product; DMG, Hamburg) to arrest progression of proximal non-cavitated caries lesions as compared with placebo treatment. In 22 young adults, 29 lesion pairs with radiographic extensions into the inner half of enamel up to the outer third of dentin were included (split-mouth design). All subjects received risk-related instructions for diet, flossing and fluoridation. No unwanted effects could be observed. Radiographically 1/26 test lesions (4%) and 11/26 control lesions (42%) had progressed (p = 0.002, McNemar). After 3-year follow-up, infiltration of proximal caries lesions can be said to be efficacious to reduce lesion progression.


Operative Dentistry | 2012

Reliability of fiber post bonding to root canal dentin after simulated clinical function in vitro

Kerstin Bitter; Jorge Perdigão; M. Exner; Konrad Neumann; A. M. Kielbassa; G. Sterzenbach

The aim of this study was to investigate the effect of thermomechanical loading (TML) on the bond strength of fiber posts luted with three different resin cements. Sixty-six extracted human anterior teeth were endodontically treated and restored with fiber posts (RelyX Fiber Posts, 3M ESPE) using three commercially available resin cements and three corresponding core build-up materials (n=22 each): Panavia F 2.0/Clearfil DC Core Automix (Kuraray), Variolink II/Multicore Flow (Ivoclar Vivadent), and RelyX Unicem/Filtek Z250 (3M ESPE). Twelve specimens of each group received all-ceramic crowns and were subjected to TML. The other 10 specimens were stored in saline solution for 24 hours. The roots were sectioned and bond strength was measured using a push-out test. Adhesive interfaces of two specimens of each group subjected to TML were analyzed using field emission scanning electron microscopy (FESEM). Bond strengths of fiber posts were significantly affected by the type of resin cement (p<0.0005) and TML (p<0.0005; two-way analysis of variance). TML significantly reduced bond strengths for all materials ((6.0 (6.2) MPa)) compared with initial bond strengths ((14.9 (10.4) MPa)). RelyX Unicem resulted in significantly higher bond strengths before ((18.3 (10.3) MPa)) and after TML ((9.8 (7.5) MPa)) compared with the other materials (p<0.0005; Tukey HSD). Using FESEM, Variolink II and Panavia F demonstrated a hybrid layer partly detached from the underlying resin cement, whereas no hybrid layer was observed for RelyX Unicem. The decrease in bond strength after TML suggests that retention of fiber posts may be reduced after clinical function. Therefore, endodontically treated teeth that are restored using fiber posts may benefit from additional reinforcement via coronal restorations using adequate ferrules and/or adhesive techniques.


European Journal of Oral Sciences | 2011

Resin infiltration of proximal caries lesions differing in ICDAS codes

Sebastian Paris; Kerstin Bitter; Michael Naumann; Christof E. Dörfer; Hendrik Meyer-Lueckel

Resin infiltration of non-cavitated proximal caries lesions has been shown to inhibit further demineralization. However, the effect of resin infiltration in cavitated lesions is unknown. Therefore, the aim of this in vitro study was to evaluate infiltration patterns of proximal caries lesions differing in International Caries Detection and Assessment System (ICDAS) codes. Extracted human molars and premolars showing proximal caries lesions with and without cavitations (ICDAS codes 2-5) were etched with 15% hydrochloric acid gel and resin infiltrated according to the manufacturers instructions. Three sections from each lesion were prepared and analyzed using a dual-fluorescence staining technique and confocal microscopy. The dimensions of the demineralized and cavitated lesions areas, as well as the resin-infiltrated parts within these lesions, were measured. The demineralized parts were infiltrated from 73% to 100% (median values) but the cavities were filled only negligibly (0-5%). Teeth that had an ICDAS code of 5 showed a significantly lower percentage infiltration/filling of lesions compared to teeth with ICDAS codes of 2 and 3. It was concluded that under in vitro conditions the tested infiltrant penetrates most parts of the demineralized enamel but is not capable of filling up cavities and therefore the efficacy of caries infiltration, particularly in lesions with larger cavitations, might be impaired.


Journal of Endodontics | 2008

Bond Strength of Fiber Posts after the Application of Erbium:Yttrium-Aluminum-Garnet Laser Treatment and Gaseous Ozone to the Root Canal

Kerstin Bitter; Jörn Noetzel; Claudia Volk; Konrad Neumann; Andrej M. Kielbassa

The aim of the present study was to investigate the effects of antibacterial agents (erbium:yttrium-aluminum-garnet [Er:YAG] laser or gaseous ozone) intended to disinfect root canals on bond strengths of fiber posts compared with canals that were finally irrigated using chlorhexidine (CHX). One hundred forty-four human anterior teeth were divided into three groups (n = 48); root canal instrumentation was performed, and antimicrobial pretreatment was conducted as follows: control group: CHX, group 2: Er:YAG laser, and group 3: gaseous ozone. In all groups, fiber posts were inserted using Panavia F 2.0 (Kuraray, Osaka, Japan), Variolink II (Ivoclar Vivadent, Schaan, Liechtenstein), RelyX Unicem (3M Espe; Seefeld, Germany), or Ketac Cem (3M Espe) (n = 12 each). Push-out bond strengths to root canal dentin were affected by the type of luting agent but not by the antimicrobial pretreatment regimen. However, significant interactions between the luting agent and pretreatment could be observed, and adhesion of the self-adhesive resin cement RelyX Unicem was significantly reduced after using gaseous ozone.


Microscopy Research and Technique | 2009

Validation of two dual fluorescence techniques for confocal microscopic visualization of resin penetration into enamel caries lesions

Sebastian Paris; Kerstin Bitter; Herbert Renz; Werner Hopfenmüller; Hendrik Meyer-Lueckel

Fluorescence confocal microscopy is a useful tool to analyze the infiltration of enamel caries lesions with low‐viscosity resins (infiltrants) in vitro. The conventionally used staining technique, which comprises dye labeling of the resin, has been shown to be limited by chromatographic separation of the resin‐dye‐mixture during penetration. The aim of this study was to develop an improved dual staining technique and to compare validity and reproducibility of both methods. Human molars with proximal white spots were cut across the demineralizations. After varnishing the cut surfaces, paired lesion halves were infiltrated with an infiltrant using either one of two different staining techniques. For the conventional direct technique (A) the infiltrant was labeled with rhodamine isothiocyanate (RITC) prior to application. Using the new indirect technique (B) lesions were stained with RITC solution and subsequently infiltrated with pure infiltrant. After light curing, unbound dye was bleached by immersion in hydrogen peroxide. Remaining lesion pores were stained with sodium fluorescein solution. Penetration depths (PD) and lesion depths (LD) were evaluated by five examiners using confocal microscopy and compared with the results of scanning electron microscopic (SEM; PD) and microradiographic (TMR; LD) analysis. The indirect technique showed better correlation (intraclass coefficients) with SEM (0.990) and TMR (0.982) compared with the direct technique (SEM: 0.513; TMR: 0.702). Inter‐ and intrarater reliability was higher for technique B compared with technique A. The new indirect technique yields to more valid and reliable results to visualize infiltrant penetration into natural enamel caries lesions compared with the conventional method. Microsc. Res. Tech. 2009.


International Endodontic Journal | 2010

Influence of endodontic treatment, post insertion, and ceramic restoration on the fracture resistance of maxillary premolars

Kerstin Bitter; Hendrik Meyer-Lueckel; N. Fotiadis; Uwe Blunck; Konrad Neumann; A.M. Kielbassa; Sebastian Paris

AIM To investigate the effects of endodontic treatment, post placement and ceramic restoration type on the fracture resistance of premolars. METHODOLOGY One hundred and twenty teeth maxillary premolars were allocated to four groups (A-D; n = 30). In group A, mesio-occlusal-distal-inlays with a buccal and palatal wall of 2 mm (MOD), in group B partial onlays with palatal cusp coverage and in group C total onlays with buccal and palatal cusp coverage were prepared. Group D served as untreated controls. Groups A-C were divided into three subgroups (n = 10): (i) teeth received solely the described preparations, (ii) teeth were root filled, (iii) teeth were root filled and quartz fibre posts were placed. Teeth were restored using Computer-assisted design/computer-assisted machining-ceramic-restorations and subjected to thermo-mechanical-loading; subsequently, the buccal cusp was loaded until fracture. RESULTS Group D revealed significantly higher fracture resistance [mean (standard deviation)] [738 (272) N] compared to all other groups (P < 0.05; post hoc test Dunnett). For groups A-C, fracture resistance was significantly affected by the restoration type (P = 0.043) and endodontic treatment/post placement (P = 0.039; 2-way anova). Group A [380 (146) N] showed significantly lower fracture resistance compared to group B [470 (158) N] (P = 0.048; post hoc test Tukey). Compared to non-endodontically treated teeth [487 (120) N], root filled teeth revealed significantly lower fracture resistance [389 (171) N] (P = 0.031). CONCLUSION The restoration of cavities with a remaining wall thickness of 2 mm using ceramic MOD-inlays is inferior with respect to the fracture resistance compared to partial onlay restorations. Root filled teeth without post placement show lower fracture resistance compared to non-endodontically treated teeth.


European Journal of Oral Sciences | 2013

Various irrigation protocols for final rinse to improve bond strengths of fiber posts inside the root canal

Kerstin Bitter; Konrad Neumann; Uwe Blunck; Guido Sterzenbach

Irrigation after post space preparation and its effects on the bond strength of different adhesive strategies are still an issue of interest. The aim of the present study was to investigate the effects of various irrigation protocols (IPs) on the push-out bond strengths of fiber posts. One-hundred and fifty extracted human anterior teeth were divided into three groups (n = 50 each) and endodontically treated. The post space was irrigated before post placement using the following five IPs in each group: IP1 (control): 5 ml of distilled water; IP2: 5.25% sodium hypochlorite (NaOCl) applied with passive ultrasonic irrigation (PUI); IP3: 1% NaOCl applied with PUI; IP4: 18% ethylenediaminetetracetic acid (EDTA) followed by 5.25% NaOCl; and IP5: 2% chlorhexidine (CHX). Fiber posts placement in each group was performed using three different adhesive strategies. A self-etch adhesive system revealed higher bond strength (16.2 ± 6.9 MPa) compared with an etch-and-rinse adhesive (8.5 ± 4.2 MPa) and a self-adhesive resin cement (9.2 ± 4.7 MPa). The use of 18% EDTA/5.25% NaOCl increased the bond strength of the self-adhesive resin cement. Conversely, this IP decreased the bond strength for the etch-and-rinse adhesive system, whilst 1% NaOCl enhanced the bond strength for the same system. Consequently, each adhesive strategy may need to be adapted to a specific IP.


Acta Odontologica Scandinavica | 2012

Fiber post placement with core build-up materials or resin cements—An evaluation of different adhesive approaches

Guido Sterzenbach; Ghaleb Karajouli; Michael Naumann; Ingrid Peroz; Kerstin Bitter

Abstract Objective. To compare push-out bond strength of fiber-posts luted with different adhesive approaches to root canal dentin. Materials and methods. Forty maxillary first incisors were decoronated and endodontically treated. Specimens were randomly distributed into five groups (n = 8) and fiber-posts (DentinPost coated, Komet) were inserted using five different luting materials: etch-and-rinse adhesive systems and corresponding core-and-post material in groups 1 (DentinBond/DentinBuild, Komet) and 2 (XP Bond + SCA/Core-X flow, Densply), self-adhesive resin cements in groups 3 (RelyX Unicem, 3M Espe) and 4 (SmartCem 2, Dentsply) and a self-etch adhesive/resin cement in group 5 (ED-Primer II/Panavia F 2.0, Kuraray). The roots were sectioned into eight 1 mm thick serial slices and within 48 h push-out bond strength was investigated. Statistical analyses were performed using non-parametrical Kruskal-Wallis H-test and Mann-Whitney U-test for differences between experimental groups at p < 0.05. The failure modes were analyzed using Chi square test. Results. The bond strength [MPa] (mean/min–max) for groups 3 (12.35/3.60–32.44), 4 (13.52/4.48–30.69) and 2 (11.15/5.23–35.58) were significantly higher (p < 0.001) compared to groups 1 (6.66/2.34–24.89) and 5 (7.41/0.28–34.18). Adhesive failure between dentin and luting agent was the most frequent failure mode. Conclusions. Bond strength of fiber-posts adhesively luted to root canal dentin was significantly higher when self-adhesive resin cements were used. One (group 2) of the tested core-and-post materials/etch-and-rinse adhesive achieved comparable bond strength values.

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Guido Sterzenbach

Humboldt University of Berlin

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