Bernd Wöstmann

Justus-Liebig-Universität Gießen, Gieben, Hesse, Germany

Are you Bernd Wöstmann?

Claim your profile

Publications (59)100.45 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives: The aim of this retrospective study was to evaluate the long-term outcomes of long-span fixed dental prostheses (LSFDPs) not meeting Ante's law. Method and Materials: This study is based on the data of 36 patients who received 41 LSFDPs. The mean survival time of the LSFDPs was calculated using the Kaplan-Meier technique. The influence of the factors (gender, localization, number of abutments, Kennedy Class, dentition of the opposing jaw) were analyzed (log-rank test and Cox regression; P < .05). Results: During the observation period, 22.0% (n = 9) of the LSFDPs ceased to function. The calculated outcome probability after 3 years was 88.3%, and 57.4% after 5 years. The only significant difference in the mean survival time could be found in LSFDPs with two abutment teeth in comparison with LSFDPs with three and more abutment teeth. Although all of the patients were invited to an oral health and maintenance program regularly, only 13.8% attended. Conclusion: The results, taken together with data from the literature, indicate that the patient's compliance is a crucial factor in the successful implementation of a LSFDP, whereas other factors are of minor importance.
    Quintessence international (Berlin, Germany: 1985) 09/2014; · 0.64 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In a multicentre randomised trial (German Research Association, grants DFG WA 831/2-1 to 2-6, WO 677/2-1.1 to 2-2.1.; controlled-trials.com ISRCTN97265367), patients with complete molar loss in one jaw received either a partial removable dental prosthesis (PRDP) with precision attachments or treatment according to the SDA concept aiming at pre-molar occlusion. The objective of this current analysis was to evaluate the influence of different treatments on periodontal health. Linear mixed regression models were fitted to quantify the differences between the treatment groups. The assessment at 5 years encompassed 59 patients (PRDP group) and 46 patients (SDA group). For the distal measuring sites of the posterior-most teeth of the study jaw, significant differences were found for the plaque index according to Silness and Löe, vertical clinical attachment loss (CAL-V), probing pocket depth (PPD) and bleeding on probing. These differences were small and showed a slightly more unfavourable course in the PRDP group. With CAL-V and PPD, significant differences were also found for the study jaw as a whole. For CAL-V, the estimated group differences over 5 years amounted to 0·27 mm (95% CI 0·05; 0·48; P = 0·016) for the study jaw and 0·25 mm (95% CI 0·05; 0·45; P = 0·014) for the distal sites of the posterior-most teeth. The respective values for PPD were 0·22 mm (95% CI 0·03; 0·41; P = 0·023) and 0·32 mm (95% CI 0·13; 0·5; P = 0·001). It can be concluded that even in a well-maintained patient group statistically significant although minor detrimental effects of PRDPs on periodontal health are measurable.
    Journal of Oral Rehabilitation 03/2014; · 2.34 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this multi-center, randomized controlled trial was to assess the impact of missing posterior support on the risk for temporomandibular disorder (TMD) pain by comparing patients with either shortened dental arches (SDA) or molar replacement by removable dental prostheses (RDP). A sample of 215 patients with bilateral molar loss in at least one jaw was consecutively recruited in 14 prosthodontic departments of dental schools in Germany. Of the initial sample, 152 patients (mean age: 59.7 years; 53.9 % female) received randomly allocated interventions (SDA: n = 71; RDP: n = 81). Presence of TMD pain was assessed using patients' self-reports and was verified by physical examination and by pain intensity, as the mean of current pain, worst pain, and average pain in the last 6 months, with 10-point ordinal rating scales. Assessments were performed before treatment and at follow-ups until 60 months after treatment. Impact of interventions on TMD risk and pain intensity was computed by applying logistic and linear random-intercept models. Tooth replacement (RDP) did not significantly change the risk for self-reported (odds ratio [OR]: 1.1; confidence interval [CI]: 0.4 to 3.4) or clinically verified (OR: 0.7; CI: 0.1 to 4.3) TMD pain compared to no tooth replacement (SDA). Mean characteristic pain intensity was virtually identical in both groups (Coeff: 0.01; CI: -0.30 to 0.32). Retaining or preservation of an SDA is not a major risk factor for TMD pain over the course of 5 years when compared to molar replacement with RPDs. Seemingly, missing molars do not have to be replaced in order to prevent TMD pain.
    Clinical Oral Investigations 01/2014; · 2.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVES: Although the shortened dental arch (SDA) concept is a widely accepted strategy to avoid overtreatment, little is known on its impact on oral health-related quality of life (OHRQoL). This multicenter randomized controlled trial aimed to investigate the OHRQoL for removable partial dental prostheses (RPDP) with molar replacement versus the SDA concept. MATERIAL AND METHODS: In both groups, missing anterior teeth were replaced with fixed dental prosthesis. Two hundred fifteen patients with bilateral molar loss in at least one jaw were included. The Oral Health Impact Profile (OHIP-49) was completed before; 6 weeks (baseline), 6 months, and 12 months after treatment; and thereafter annually until 5 years. RESULTS: Of the initial cohort, 81 patients were assigned to the RPDP group and 71 to the SDA group (age, 34 to 86 years). Before treatment, the median OHIP score was similar in both groups (RPDP, 38.0; SDA, 40.0; n.s.). Results indicate marked improvements in OHRQoL in both groups between pretreatment and baseline (RPDP, 27.0; SDA, 19.0; p ≤ 0.0001) which continued in the RPDP group until the 1-year follow-up (p = 0.0002). These significant reductions in OHIP scores are reflected in its subscales. No further differences were seen within and between groups during the remainder observation period. CONCLUSION: Both treatments show a significant improvement in OHRQoL which continued in the RPDP group until the 1-year follow-up. No significant differences were seen between groups. CLINICAL RELEVANCE: For improving OHRQoL, it is not necessary to replace missing molars with a RPDP.
    Clinical Oral Investigations 05/2013; · 2.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: This retrospective clinical study aimed to evaluate the long-term outcomes of clasp-retained, metal-framework removable partial dentures (RPDs) and their clasped teeth, the influencing factors on survival, and the type and number of repairs needed during the observation period. Materials and Methods: The study is based on a convenience sample of 52 patients who received 65 RPDs with a total of 207 clasped teeth. The mean observation period was 3.11 ± 0.29 years (maximum: 10 years). Patient gender, prosthesis location (maxilla/mandible), number and distribution (Kennedy class) of abutment teeth, and impact of a continuous follow-up program on a favorable outcome probability were analyzed. Statistical analysis was performed using the Kaplan-Meier method (P < .05) in combination with Cox regression analysis. Results: During the observation period, 9.2% of the RPDs ceased to function and 5.8% of the abutment teeth were extracted. Mean RPD survival time was 8.07 ± 0.66 years, with a positive outcome probability of 90% after 5 years. Prosthesis location was the only parameter that significantly (P < .05) impacted this probability. Conclusion: Overall, the high survival probability and low extraction rate of the abutment teeth reported in this study indicate that RPDs designed according to hygienic pronciples are clinically successful.
    The International journal of prosthodontics 03/2013; 26(2):147-50. · 1.63 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Purpose: This in vitro study aimed to identify the effects of the implant system, impression technique, and impression material on the transfer accuracy of implant impressions. The null hypothesis tested was that, in vitro and within the parameters of the experiment, the spatial relationship of a working cast to the placement of implants is not related to (1) the implant system, (2) the impression technique, or (3) the impression material. Materials and Methods: A steel maxilla was used as a reference model. Six implants of two different implant systems (Standard Plus, Straumann; Semados, Bego) were fixed in the reference model. The target variables were: three-dimensional (3D) shift in all directions, implant axis direction, and rotation. The target variables were assessed using a 3D coordinate measuring machine, and the respective deviations of the plaster models from the nominal values of the reference model were calculated. Two different impression techniques (reposition/pickup) and four impression materials (Aquasil Ultra, Flexitime, Impregum Penta, P2 Magnum 360) were investigated. In all, 80 implant impressions for each implant system were taken. Statistical analysis was performed using multivariate analysis of variance. Results: The implant system significantly influenced the transfer accuracy for most spatial dimensions, including the overall 3D shift and implant axis direction. There was no significant difference between the two implant systems with regard to rotation. Multivariate analysis of variance showed a significant effect on transfer accuracy only for the implant system. Conclusions: Within the limits of the present study, it can be concluded that the transfer accuracy of the intraoral implant position on the working cast is far more dependent on the implant system than on the selection of a specific impression technique or material.
    The International journal of oral & maxillofacial implants 01/2013; 28(4):989-95. · 1.91 Impact Factor
  • Paul Seelbach, Cora Brueckel, Bernd Wöstmann
    [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVES: Digital impression techniques are advertised as an alternative to conventional impressioning. The purpose of this in vitro study was to compare the accuracy of full ceramic crowns obtained from intraoral scans with Lava C.O.S. (3M ESPE), CEREC (Sirona), and iTero (Straumann) with conventional impression techniques. MATERIALS AND METHODS: A model of a simplified molar was fabricated. Ten 2-step and 10 single-step putty-wash impressions were taken using silicone impression material and poured with type IV plaster. For both techniques 10 crowns were made of two materials (Lava zirconia, Cera E cast crowns). Then, 10 digital impressions (Lava C.O.S.) were taken and Lava zirconia crowns manufactured, 10 full ceramic crowns were fabricated with CEREC (Empress CAD) and 10 full ceramic crowns were made with iTero (Copran Zr-i). The accessible marginal inaccuracy (AMI) and the internal fit (IF) were measured. RESULTS: For AMI, the following results were obtained (mean ± SD): overall groups, 44 ± 26 μm; single-step putty-wash impression (Lava zirconia), 33 ± 19 μm; single-step putty-wash impression (Cera-E), 38 ± 25 μm; two-step putty-wash impression (Lava zirconia), 60 ± 30 μm; two-step putty-wash impression (Cera-E), 68 ± 29 μm; Lava C.O.S., 48 ± 25 μm; CEREC, 30 ± 17 μm; and iTero, 41 ± 16 μm. With regard to IF, errors were assessed as follows (mean ± SD): overall groups, 49 ± 25 μm; single-step putty-wash impression (Lava zirconia), 36 ± 5 μm; single-step putty-wash impression (Cera-E), 44 ± 22 μm; two-step putty-wash impression (Lava zirconia), 35 ± 7 μm; two-step putty-wash impression (Cera-E), 56 ± 36 μm; Lava C.O.S., 29 ± 7 μm; CEREC, 88 ± 20 μm; and iTero, 50 ± 2 μm. CONCLUSIONS: Within the limitations of this in vitro study, it can be stated that digital impression systems allow the fabrication of fixed prosthetic restorations with similar accuracy as conventional impression methods. CLINICAL RELEVANCE: Digital impression techniques can be regarded as a clinical alternative to conventional impressions for fixed dental restorations.
    Clinical Oral Investigations 10/2012; · 2.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The storage time and conditions of irreversible hydrocolloid impressions affect their accuracy and in turn the precision of the definitive cast. Recommendations for proper storage are, however, based on theoretical assumptions rather than facts. The purpose of this study was to assess the influence of the 2 most common storage conditions on the dimensional stability of 7 contemporary irreversible hydrocolloids (IH) for a period of up to 7 days. Twelve specimens per material (Blueprint, Cavex CA37, Cavex ColorChange, Jeltrate, Orthoprint, Cavex Orthotrace, and Tetrachrom) were fabricated according to ISO/CD 21563. The specimens were either stored in a humidor (n=6) or wrapped in a wet tissue (n=6) inside a plastic bag (bag/tissue). The linear dimensional change of the specimens was calculated (Δ| [%]) at baseline and after a storage time of 1, 2, 4, 24, 48, 72, 120, and 168 hours. Data were subjected to a repeated measures ANOVA, followed by post hoc comparisons (Tukey HSD Test, Games-Howell Test) at α=.05. For specimens stored in the humidor, Δ| ranged from 0.33% to -2.35% and in the bag/tissue from 2.89% to -2.8%. Storage in the bag/tissue resulted in the most unpredictable results. The color-changing IH showed a pronounced expansion when stored in the bag/tissue. If humidor storage is used, IH impressions should be poured within 4 hours. If bag/tissue storage is used, noncolor-change IH impressions should, preferably, be poured within 2 hours. In general, the color-change IHs studied had higher dimensional change values. For optimum dimensional stability, IH impressions should be poured as soon as possible.
    The Journal of prosthetic dentistry 08/2012; 108(2):114-22. · 1.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The scientific evidence concerning prosthodontic care for the shortened dental arch (SDA) is sparse. This randomized multicenter study aimed to compare two common treatment options: removable partial dental prostheses (RPDPs) for molar replacement vs. no replacement (SDA). One of the hypotheses was that the follow-up treatment differs between patients with RPDPs and patients with SDAs during the 5-year follow-up period. Two hundred and fifteen patients with complete molar loss in one jaw were included in the study. Molars were either replaced by RPDPs or not replaced according to the SDA concept. A mean number of 4.2 (RPDP) and 2.8 (SDA) treatments for biological or technical reasons occurred during the 5-year observation time per patient. Concerning the biological aspect, no significant differences between the groups could be shown, whereas treatment arising from technical reasons was significantly more frequent for the RPDP group. When the severity of treatment was analyzed, a change over time was evident. When, at baseline, only follow-up treatment with minimal effort is required, over time there is a continuous increase to moderate and extensive effort observed for both groups (Controlled-trials.com number ISRCTN97265367).
    Journal of dental research 07/2012; 91(7 Suppl):65S-71S. · 3.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: OBJECTIVES: The study was designed to provide clinical outcome data for two treatments of the shortened dental arch (SDA). MATERIAL AND METHODS: In a multicenter randomized controlled clinical trial, patients with complete molar loss in one jaw were provided with either a partial removable dental prosthesis (PRDP) retained with precision attachments or treated according to the SDA concept preserving or restoring a premolar occlusion. No implants were placed. The primary outcome was tooth loss. RESULTS: Of 152 treated patients, 132 patients reached the 5-year examination. Over 5 years, 38 patients experienced tooth loss. For the primary outcome tooth loss, the Kaplan-Meier survival rates at 5 years were 0.74 (95 % CI 0.64, 0.84) in the PRDP group and 0.74 (95 % CI 0.63, 0.85) in the SDA group. For tooth loss in the study jaw, the survival rates at 5 years were 0.88 (95 % CI 0.80, 0.95) in the PRDP group and 0.84 (95 % CI 0.74, 0.93) in the SDA group. The differences were not significant. No Cox regression models of appropriate fit explaining tooth loss on the patient level could be found. CONCLUSIONS: The overall treatment goals of a sustainable oral rehabilitation and the avoidance of further tooth loss over longer periods were not reliably achievable. The influence of the type of prosthetic treatment on tooth loss might have been overestimated. CLINICAL RELEVANCE: Regarding our results, the patient's view will gain even more importance in the clinical decision between removable and fixed restorations in SDAs.
    Clinical Oral Investigations 06/2012; · 2.20 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Despite the success in preventing oral diseases, the prevalence of tooth loss in the German population remains high and increases with age. Today, the advances in prosthetic dentistry allow necessary tooth replacement following preventive strategies-after considering benefits and risks. Modern treatment options improve the overall prognosis of the stomatognathic system and the quality of life of the affected patients significantly. Hereby, adverse iatrogenic effects can be minimized or even completely avoided by extending the traditional treatment spectrum, e.g., using adhesively fixed restorations and implant-supported restorations, and refraining from placing restorations that are unnecessary from the medical point of view. Generally, patients benefit greatly from prosthetic treatment and the achieved health gain is remarkably high. It encompasses not only the recovery of the impaired oral functions but also extends to the whole human organism, including nutrition, digestion, musculoskeletal system, as well as mental and social well-being.
    Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 08/2011; 54(9):1102-9. · 0.72 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to evaluate the clinical long-term performance of a visible light-cured resin (VLCR) denture base material and to compare it to a well-established polymethylmethacrylate (PMMA)-based denture acrylic in a randomized split-mouth clinical long-term study. One hundred removable partial dentures in 90 patients, with at least two saddles each, were investigated. One saddle was made of VLCR, while the other was made of PMMA at random. Plaque adhesion, tissue reaction, and technical parameters of the dentures were assessed 6, 12, and 18 months after treatment. Statistical analysis was performed using the Wilcoxon rank-sum test. Though VLCR showed higher plaque adhesion than PMMA after 6, 12, and 18 months (p < 0.001), there were no important differences with regard to tissue reaction. Concerning plaque adhesion, surface quality with regard to the lower side, interfaces between denture acrylic and metal and the boundary between denture acrylic and denture tooth PMMA was rated higher than VLCR. The surface quality of the upper side of the denture saddles showed no significant differences (p > 0.05). Neither VLCR nor PMMA showed discoloration at any point in time (p > 0.05). It can be concluded that VLCR is a viable alternative for the production of removable dentures. Especially in patients with hypersensitivities to PMMA, VLCR is particularly suitable for clinical use.
    Clinical Oral Investigations 06/2011; 16(3):969-75. · 2.20 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Trotz aller Erfolge in der Prävention von Zahnerkrankungen hat der Zahnverlust auch heute noch eine hohe Prävalenz in der deutschen Bevölkerung, die mit zunehmendem Lebensalter kontinuierlich steigt. Der medizinische Fortschritt in der prothetischen Zahnmedizin ermöglicht heute den notwendigen Ersatz fehlender Zähne mit präventionsorientierten Strategien unter konsequenter Gegenüberstellung von Nutzen und Risiken. Hier verbessern moderne Therapiemittel die Gesamtprognose des Kauorgans und die Lebensqualität der betroffenen Patienten deutlich. Die iatrogene Schädigung wird dabei so gering wie möglich gehalten. Iatrogene Schädigungen werden vor allem durch die Erweiterung des konventionellen prothetischen Behandlungsspektrums mittels adhäsiv befestigter und implantatgetragener Therapiemittel sowie durch den Verzicht auf medizinisch nicht erforderlichen Zahnersatz minimiert oder sogar vermieden. Der Gesundheitsgewinn durch zahnärztlich-prothetische Therapiemittel ist für die betroffenen Patienten in der Regel außerordentlich hoch und beinhaltet nicht nur die Wiederherstellung der durch Zahnverlust eingeschränkten orofazialen Funktionen, sondern erstreckt sich auf den gesamten menschlichen Organismus. Dabei sind vor allem Ernährung, Verdauung, Bewegungsapparat und psychisches und soziales Wohlbefinden zu nennen. Despite the success in preventing oral diseases, the prevalence of tooth loss in the German population remains high and increases with age. Today, the advances in prosthetic dentistry allow necessary tooth replacement following preventive strategies—after considering benefits and risks. Modern treatment options improve the overall prognosis of the stomatognathic system and the quality of life of the affected patients significantly. Hereby, adverse iatrogenic effects can be minimized or even completely avoided by extending the traditional treatment spectrum, e.g., using adhesively fixed restorations and implant-supported restorations, and refraining from placing restorations that are unnecessary from the medical point of view. Generally, patients benefit greatly from prosthetic treatment and the achieved health gain is remarkably high. It encompasses not only the recovery of the impaired oral functions but also extends to the whole human organism, including nutrition, digestion, musculoskeletal system, as well as mental and social well-being. SchlüsselwörterGesundheit–Implantate–Lebensqualität–Prothetik–Zahnersatz KeywordsHealth–Implants–Quality of life–Prosthetic dentistry–Tooth replacement
    Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 01/2011; 54(9):1102-1109. · 0.72 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study aimed at investigating the influence of fabrication method, storage condition and material on the fracture strength of temporary 3-unit fixed partial dentures (FPDs). A CrCo-alloy master model with a 3-unit FPD (abutment teeth 25 and 27) was manufactured. The master model was scanned and the data set transferred to a CAD/CAM unit (Cercon Brain Expert, Degudent, Hanau, Germany). Temporary 3-unit bridges were produced either by milling from pre-fabricated blanks (Trim, Luxatemp AM Plus, Cercon Base PMMA) or by direct fabrication (Trim, Luxatemp AM Plus). 10 FPDs per experimental group were subjected either to water storage at 37 °C for 24h and 3 months, respectively, or thermocycled (TC, 5000×, 5-55 °C, 1 week). Maximum force at fracture (Fmax) was determined in a 3-point bending test at 200 mm/min. Data was analyzed using parametric statistics (α = 5%). Fmax values ranged from 138.5 to 1115.5N. FPDs, which were CAD/CAM fabricated, showed a significant higher Fmax compared to the directly fabricated bridges (p < 0.05). TC significantly affected Fmax for Luxatemp (p < 0.05) but not for the PMMA based materials (p > 0.05). CAD/CAM milled FPDs made of Luxatemp showed significantly higher Fmax values compared to Trim and Cercon Base PMMA (p < 0.05). CAD/CAM fabricated FPDs exhibit a higher mechanical strength compared to directly fabricated FPDs, when manufactured of the same material. Composite based materials seem to offer clear advantages versus PMMA based materials and should, therefore, be considered for CAD/CAM fabricated temporary restorations.
    Dental materials: official publication of the Academy of Dental Materials 12/2010; 27(4):339-47. · 2.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to investigate the effects of polymerization contraction, shrinkage stress and Young's modulus of nanofiller containing resin composites on early marginal adaptation of restorations in cavities. Six nanofiller containing and two reference resin composites were studied. Marginal gap widths of restorations in cylindrical 4.2mm wide and 1.5mm deep dentin cavities, non-bonded or bonded with a self-etch adhesive, and in Teflon cavities of same dimensions were determined 15 min after irradiation (n=8). Polymerization shrinkage strains were measured using the bonded-disk (n=8) and a strain gage method (n=8). For determination of contraction stress the composites (n=10) were bonded to and cured in Araldit molds using a photoelastic method. Flexural moduli of the restoratives were studied according to ISO specification 4049 (n=5). Statistical analysis was performed with one- and two-way ANOVA, Kruskal-Wallis ANOVA test and post hoc tests (p<0.05). Only two nanofiller composites (Kalore, GC, Japan) and Venus Diamond (Heraeus Kulzer, Germany) showed consistently gap-free margins in bonded dentin cavities. The mean gap widths in non-bonded and in Teflon cavities were 6.1-12.8 and 14.1-25.5 μm, and linearly correlated (r(2)<0.85). Significant linear relationships were observed between strain, stress and marginal gap widths in non-bonded and Teflon cavities (p<0.01). Flexural moduli (15 min) were between 1.66 and 8.63 GPa. Marginal cavity adaptation of restorations in bonded dentin cavities reflects complex interactions between adhesive bonding on the one hand, and polymerization contraction strain, stress and elastic modulus, on the other.
    Dental materials: official publication of the Academy of Dental Materials 09/2010; 26(12):1166-75. · 2.88 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The evidence concerning the management of shortened dental arch (SDA) cases is sparse. This multi-center study was aimed at generating data on outcomes and survival rates for two common treatments, removable dental prostheses (RDP) for molar replacement or no replacement (SDA). The hypothesis was that the treatments lead to different incidences of tooth loss. We included 215 patients with complete molar loss in one jaw. Molars were either replaced by RDP or not replaced, according to the SDA concept. First tooth loss after treatment was the primary outcome measure. This event occurred in 13 patients in the RDP group and nine patients in the SDA group. The respective Kaplan-Meier survival rates at 38 months were 0.83 (95% CI: 0.74-0.91) in the RDP group and 0.86 (95% CI: 0.78-0.95) in the SDA group, the difference being non-significant.
    Journal of dental research 08/2010; 89(8):818-22. · 3.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Upon removal, tear forces occur in various areas of an impression. As a result, thin sulcus details may be permanently deformed, affecting the impression's accuracy. The purpose of this study was to investigate the effect of the chemistry and prolonged setting time on the permanent deformation of light-body impression materials after stretching. A dumbbell-shaped mold (2 mm x 4 mm x 75 mm) was used to prepare specimens (n=20) of 6 different impression materials (Affinis Light Body, Aquasil Ultra XLV, Express 2 Light Body Flow Quick, Flexitime Correct Flow, P2 Polyether Light, and Impregum Garant L DuoSoft). After water storage (35 degrees C), either for the manufacturer's suggested setting time or for 5 minutes, specimens were stretched by 80% using a universal testing machine at a crosshead speed of 200 mm/min. The permanent deformation (Deltal (%)) was determined after 2 hours of storage in ambient conditions. A 2-way ANOVA followed by a Games-Howell test was used to analyze the influence of material and storage time (alpha=.05). Polyether materials showed a significantly higher permanent deformation (Deltal>4% to 5%) than vinyl polysiloxane materials (P<.05). Extending the manufacturer's suggested setting time resulted in clinically relevant improvements in elastic recovery for products with a polyether backbone only. Increasing the setting time might be necessary for impression materials with a polyether backbone to improve elastic recovery.
    The Journal of prosthetic dentistry 05/2010; 103(5):288-94. · 1.22 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Various treatment options for the prosthetic treatment of jaws where all molars are lost are under discussion. Besides the placement of implants, two main treatment types can be distinguished: replacement of the missing molars with removable dental prostheses and non-replacement of the molars, i.e. preservation of the shortened dental arch. Evidence is lacking regarding the long-term outcome and the clinical performance of these approaches. High treatment costs and the long time required for the treatment impede respective clinical trials. This 14-center randomized controlled investigator-initiated trial is ongoing. Last patient out will be in 2010. Patients over 35 years of age with all molars missing in one jaw and with at least both canines and one premolar left on each side were eligible. One group received a treatment with removable dental prostheses for molar replacement (treatment A). The other group received a treatment limited to the replacement of all missing anterior and premolar teeth using fixed bridges (treatment B). A pilot trial with 32 patients was carried out. Two hundred and fifteen patients were enrolled in the main trial where 109 patients were randomized for treatment A and 106 for treatment B. The primary outcome measure is further tooth loss during the 5-year follow-up. The secondary outcome measures encompassed clinical, technical and subjective variables. The study is funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG WA 831/2-1, 2-2, 2-3, 2-4, 2-5). The particular value of this trial is the adaptation of common design components to the very specific features of complex dental prosthetic treatments. The pilot trial proved to be indispensable because it led to a number of adjustments in the study protocol that considerably improved the practicability. The expected results are of high clinical relevance and will show the efficacy of two common treatment approaches in terms of oral health. An array of secondary outcome measures will deliver valuable supplementary information. If the results can be implemented in the clinical practice, the daily dental care should strongly profit thereof. The trial is registered at ClinicalTrials.gov under ISRCTN68590603 (pilot trial) and ISRCTN97265367 (main trial).
    Trials 02/2010; 11:15. · 2.21 Impact Factor
  • Source
    P. Seelbach, P. Rehmann, B. Wöstmann
    [Show abstract] [Hide abstract]
    ABSTRACT: Die konventionelle Abformung als klassischer Übertragungsweg der klinischen Mundsituation auf die Modellsituation im Dentallabor wird seit über 100Jahren in prinzipiell unveränderter Weise durchgeführt und ist für die meisten Teilgebiete der Zahnmedizin nach wie vor von zentraler Bedeutung. Trotz kontinuierlicher Weiterentwicklung der verwendeten Abformmaterialien und -techniken ist die Abformprozedur für die Patienten in der Regel unangenehm, und die Resultate sind qualitativ häufig unbefriedigend. Mit den gegenwärtig erhältlichen digitalen Abformsystemen ist es möglich, intraorale Scans der Zähne herzustellen, deren Präzision mit der der konventionell hergestellten Modelle vergleichbar ist oder diese sogar übertrifft. Der folgende Beitrag beschäftigt sich mit den Vor- und Nachteilen dieser neuen Technik und versucht darüber hinaus, Tipps zu deren praktischer Anwendung zu geben. SchlüsselwörterOptische Abformung–Digitale Scansysteme–SLA-Modell–CAD/CAM–Konventionelle Abformung
    01/2010; 4(4):17-24.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Vinylpolysiloxane impression materials (VPS) exhibit an apolar (hydrophobic) backbone chemistry. Hence, surfactants are added to improve their hydrophilicity for impression-taking in moist environments. However, the mechanisms at the liquid-VPS-interface regarding the surfactant are unknown. We hypothesized that surfactant is leached from the VPS. Four experimental VPS formulations were fabricated containing 0 (control), 1.5, 3, and 5 wt% non-ionic surfactant. Samples were prepared (n = 6) and contact angles determined 30 min after mixing. After 60 sec, droplets were transferred onto the control. Mass spectrometry was used to analyze the droplets. Contact angles were inversely correlated with the surfactant concentration (p < 0.05). Droplets transferred from hydrophilized specimens onto the control showed similar contact angles. Surfactant could be clearly identified inside the droplets from the hydrophilized samples, however, not inside the control. Surfactants reduced the surface tension of the liquid in contact and did not change the surface properties of the VPS itself.
    Journal of dental research 07/2009; 88(7):668-72. · 3.46 Impact Factor

Publication Stats

334 Citations
100.45 Total Impact Points

Institutions

  • 2005–2014
    • Justus-Liebig-Universität Gießen
      Gieben, Hesse, Germany
  • 2012–2013
    • RWTH Aachen University
      • Department of Prosthodontics and Dental Materials
      Aachen, North Rhine-Westphalia, Germany
    • Johannes Gutenberg-Universität Mainz
      Mayence, Rheinland-Pfalz, Germany
  • 2011
    • Christian-Albrechts-Universität zu Kiel
      Kiel, Schleswig-Holstein, Germany
  • 2010
    • Tokyo Medical and Dental University
      • Department of Restorative Sciences
      Tokyo, Tokyo-to, Japan
  • 2002
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 1991
    • University of Münster
      Muenster, North Rhine-Westphalia, Germany