Publications by authors named "Anja Liebermann"

54 Publications

Innovative tooth-colored CAD/CAM polycarbonate splint design for prosthetic rehabilitation of a young ectodermal dysplasia patient with permanent tooth aplasia.

Quintessence Int 2021 Jun 2;0(0):2-12. Epub 2021 Jun 2.

Ectodermal dysplasia (ED) is one of the congenitally syndromic diseases with dental anomalies. This syndrome manifests in various forms and usually requires early restorative therapy to restore esthetics and function in young patients. The restorative approaches vary greatly and range from minimally invasive shape corrections using composite build-ups and removable partial or complete dental prostheses, to implantologic solutions, always based on the syndromic expression, the age of the patient, the residual growth, as well as the dentition itself. The present case report presents an innovative prosthetic management of a young patient suffering from ED with permanent tooth aplasia and persistent primary teeth using maxillomandibular individually veneered tooth-colored CAD/CAM polycarbonate splints. The CAD phase has been significantly improved by including the analysis of 3D face scans. This advanced technical development makes it possible to avoid any time-consuming try-in and start directly with the splint production, ensuring a much faster complete rehabilitation and support for the young patient.
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http://dx.doi.org/10.3290/j.qi.b1492063DOI Listing
June 2021

Dental education during the pandemic: Cross-sectional evaluation of four different teaching concepts.

J Dent Educ 2021 May 27. Epub 2021 May 27.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.

Objectives: To evaluate the advantages of student satisfaction with and functionality of three digital teaching concepts during the SARS-CoV-2 pandemic compared to a conventional lecture setup.

Methods: This cross-sectional study was a survey-based e-learning research among dental students in the clinical study phase of a department of prosthetic dentistry at a German university hospital. A total of 44 questions were answered in four main sections: 1. general technical components; 2. acceptance; 3. evaluation and functionality; and 4. overall evaluation and grades of the various digital concepts. The use of Zoom conference, livestream, and prerecorded PowerPoint was compared to the conventional lecture setup (control group/CG). Data were analyzed using the Kolmogorov-Smirnov test, followed by an exploratory data analysis and Cronbach's alpha test (α = 0.05).

Results: Students were very satisfied with the provision, quality, and benefit of the digital concepts. The asynchronous concept was significantly more satisfying than the synchronous concepts in many aspects but was less successful in interactions. In the overall evaluation and grading, the asynchronous concept was rated significantly better than the other synchronous concepts (p ≤ 0.007), followed by Zoom conference, conventional lecture (CG), and livestream, while Zoom conference and the conventional lecture showed no significant difference (p = 0.784).

Conclusions: Students significantly preferred the asynchronous concept to the synchronous concepts. The results suggested that asynchronous concepts are an effective and functional form of distance education during a pandemic. In general, digital teaching concepts are currently widely accepted for maintaining university education.
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http://dx.doi.org/10.1002/jdd.12653DOI Listing
May 2021

Optical Behavior of Zirconia-Based Restorations Over Teeth and Implants in the Esthetic Zone: A Clinical Report.

Compend Contin Educ Dent 2021 May;42(5):236-241

Professor, Department of Dentistry, Federal University of Santa Catarina, Florianópolis, Brazil.

While various zirconia-based alternatives are available today for the restoration of teeth and implants in the esthetic zone, each treatment approach could result in different optical behavior. To clinically demonstrate these differences, this case report describes a rehabilitation in the esthetic zone using several options of teeth- and implant-supported restorations. Conventional veneered zirconia crowns, high-translucent monolithic zirconia crowns, and minimally veneered high-translucent zirconia crowns were proposed and assessed under different light sources before cementation. The patient and clinical team achieved consensus on the minimally veneered high-translucent zirconia crowns, which were then cemented and have performed well over both tooth and implant substrates.
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May 2021

Impact of resin composite cement on color of computer-aided design/computer-aided manufacturing ceramics.

J Esthet Restor Dent 2021 May 5. Epub 2021 May 5.

Department of Prosthetic Dentistry, LMU Munich, Munich, Germany.

Objective: To analyze the impact of the color of a resin composite cement (RCC) on the optical properties of different computer-aided design and computer-aided manufacturing (CAD/CAM) ceramics.

Materials And Methods: Specimens (N = 220, thickness: 0.9 ± 0.03 mm) were fabricated from: leucite (Initial LRF Block/IPS Empress CAD), lithium disilicate (Amber Mill/IPS e.max CAD), lithium metasilicate (Celtra Duo), and lithium alumina silicate ceramic (n!ce) in translucency levels HT and LT. All specimens were bonded with an RCC (Light+/Warm+). Color was analyzed (spectrophotometer) initially as well as after bonding of RCC with CAD/CAM ceramics using CIELab and CIEDE2000. Kolmogorov-Smirnov test, one-way ANOVA and t test served for analyzing (α = 0.05).

Results: Highest impact on ΔE presented the choice of ceramic (η  = 0.155/p < 0.001), followed by translucency level (HT/LT; η  = 0.050/p = 0.001) as well as interaction between ceramic and translucency level (η  = 0.175/p < 0.001). ΔE00 was mainly influenced by the choice of ceramic (η  = 0.490/p < 0.001), the shade of resin composite (η  = 0.031/p = 0.012) as well as the interaction between ceramic and resin composite (η  = 0.258/p < 0.001).

Conclusions: RCC shades presented differential impacts on color change of CAD/CAM ceramics.

Clinical Significance: Knowledge of the impact of available RCC shades on different CAD/CAM ceramics is crucial for an esthetic outcome and proper selection of ceramic restorations.
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http://dx.doi.org/10.1111/jerd.12738DOI Listing
May 2021

Impact of Missing Teeth on Oral-Health-Related Quality of Life: A Prospective Bicenter Clinical Trial.

Int J Prosthodont 2021 Mar 18. Epub 2021 Mar 18.

Purpose: To investigate the effect of missing teeth on patients' oral health-related quality of life (OHRQoL).

Materials And Methods: A total of 151 patients participated in this prospective bicenter clinical study (mean age: 64.7 ± 10.5 years; 71 women). Four subgroups were defined based on the number of missing teeth. OHRQoL was assessed using the German version of the Oral Health Impact Profile-49/53 (OHIP-G49/53) and visual analog scale (VAS) questionnaires. The effect of missing teeth on OHIP (total and by dimension) and VAS scores before and after prosthetic treatment was investigated at baseline (T0), 1 week (T1), and 3 months (T2) after prosthetic treatment. Scores were analyzed using Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests. Correlations were assessed using Spearman rho correlation. The level of significance was set at P = .05.

Results: Initial OHIP and VAS scores were highest for patients with 11 to 28 missing teeth. Scores improved among all groups between T0 and T1/T2. After prosthetic rehabilitation (T1), improvements in total OHIP scores were greatest for patients with no missing teeth or with 11 to 28 missing teeth. Patients with no missing teeth or with 1 to 4 missing teeth before treatment had the lowest posttreatment OHIP scores. Total OHIP scores among the groups were in the same value range (P > .185). No direct correlation was found between the VAS and total OHIP scores.

Conclusion: OHIP and VAS scores for OHRQoL were associated with the number of missing teeth. Prosthetic treatment resulted in improved OHRQoL and oral function among all groups. The use of a VAS yielded additional detailed information.
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http://dx.doi.org/10.11607/ijp.7422DOI Listing
March 2021

Modern CAD/CAM silicate ceramics, their translucency level and impact of hydrothermal aging on translucency, Martens hardness, biaxial flexural strength and their reliability.

J Mech Behav Biomed Mater 2021 06 13;118:104456. Epub 2021 Mar 13.

Department of Prosthetic Dentistry, LMU Munich, Munich, Germany.

Objectives: To investigate the impact of hydrothermal aging on Martens parameter (Martens hardness: HM/elastic indentation modulus: E) and biaxial flexural strength (BFS) of recently available CAD/CAM silicate ceramics.

Methods: 220 specimens (diameter: 12 mm, thickness: 0.95 mm) were fabricated from six CAD/CAM ceramics in two translucency levels (LT/HT): (a) two lithium disilicate (Amber Mill, ABM; IPS e.max CAD, IEM), (b) one lithium metasilicate (Cetra Duo, CEL), (c) one lithium alumina silicate (n!ce, NIC), and (d) two leucite ceramics (Initial LRF Block, LRF; IPS Empress CAD, IPR). HM/E and BFS were measured initially and after hydrothermal aging (134 °C/0.2 MPa/100 h) in an autoclave. The Kolmogorov-Smirnov-test, t-test, one-way ANOVA with post-hoc Scheffé test, Kruskal-Wallis-test, Mann-Whitney-U-test with Bonferroni correction and Weibull statistics were performed (α = 0.05).

Results: CEL and IEM showed the highest and the leucite ceramics the lowest Martens parameter. Within HT, ABM and NIC were in same initial HM value range with CEL and IEM. ABM and NIC showed lower initial E values than CEL and IEM, however higher than IPR. The lowest aged values were analyzed for ABM. After aging, Martens parameter decreased for LRF, ABM, and CEL. IEM showed the initial highest BFS, followed by ABM. NIC and LRF showed the lowest BFS. IEM and ABM presented the highest aged BFS. Hydrothermal aging increased BFS values for LRF (HT), IPR, CEL (HT), and NIC (HT) compared to the initial values. CAD/CAM leucite ceramics showed higher Weibull modul values compared to lithium silicate ceramics.

Significance: The well-considered selection of ceramics in relation to the areas of indication has the highest influence on the long-term stability of restorations: CAD/CAM lithium disilicate ceramics presented the highest and leucite ceramics the lowest mechanical properties, whereas the reliability was better for leucite than for lithium silicate ceramics.
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http://dx.doi.org/10.1016/j.jmbbm.2021.104456DOI Listing
June 2021

Food solutions and cigarette smoke-dependent changes in color and surface texture of CAD/CAM resin composites - an in vitro study.

Int J Prosthodont 2021 Feb 23. Epub 2021 Feb 23.

Purpose: To investigate the discoloration and surface properties of four CAD/CAM composite resins provoked by a variety of food solutions and cigarette smoke.

Materials And Methods: A total of 74 specimens (N = 370) were prepared per material (Brilliant Crios [Coltene], CeraSmart [GC], Lava Ultimate [3M Espe], Shofu Block HC [Shofu], and SonicFill 2 [Kerr]). Discoloration (ΔE) was investigated with a spectrophotometer. Measurements were taken before immersion in the storage media for 2 weeks (carrot juice, curry, cigarette smoke, red wine, energy drink, and distilled water), immediately after immersion, and after manual polishing of the specimens following immersion. The mean surface roughness (Ra) was measured using a profilometer. Qualitative surface observation was performed with scanning electron microscopy (SEM). Data were analyzed using Kolmogorov-Smirnov, Mann-Whitney U, and one-way analysis of variance with Tukey post hoc tests.

Results: The highest influence on ΔE after immersion was observed by the storage medium (η. = 0.878, P < .001), followed by the interaction between storage medium and material (η. = 0.770, P < .001) and the material (η. = 0.306, P < .001). For ΔE after polishing, the highest influence was indicated by the interaction of material and medium (η. = 0.554, P < .001), followed by the medium (η. = 0.244, P < .001) and the material (η. = 0.196, P < .001). Immersion in carrot juice led to the highest color change (ΔE: 8.0 to 10.4), whereas the lowest values were recorded in distilled water (ΔE: 2.0 to 2.4). Carrot juice and the energy drink provoked the highest Ra values (0.120 to 0.355 μm). SEM pictures indicated a loss of the organic matrix after manual polishing.

Conclusion: The different materials reacted dissimilarly in the various storage media in terms of discoloration. Surface roughness increased after immersion and polishing. Neither discoloration nor surface roughness could be reset to default by manual polishing.
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http://dx.doi.org/10.11607/ijp.6950DOI Listing
February 2021

Impact of high-speed sintering on accuracy and fit of 4 mol% yttria-stabilized tetragonal zirconia polycrystals (4Y-TZPs).

Int J Prosthodont 2021 Feb 12. Epub 2021 Feb 12.

Purpose: To investigate the impact of high-speed sintering on the accuracy (trueness and reproducibility) and fit of 4Y-TZP full-coverage single-unit fixed dental prostheses (FDPs) and three-unit FDPs.

Materials And Methods: Single-unit FDPs, conventional three-unit FDPs, and cantilever three-unit FDPs (N = 108; n = 12 per subgroup) were fabricated from: (1) high-speed sintered (1,580°C, about 20 minutes) multi-layer 4Y-TZP (Zolid RS, Amann Girrbach; ZMLH group), as well as two conventionally sintered (1,450°C, about 10 hours) materials: (2) multi-layer 4Y-TZP (Zolid Gen-X, Amann Girrbach; ZMLC group) and (3) monochrome 4Y-TZP (Ceramill Zolid HT+ PS, Amann Girrbach; ZMOC group). All specimens were scanned. Trueness, reproducibility, and fit were measured with 3D analysis software. For data analysis, Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests were performed (α = .05).

Results: Three-unit FDPs made from ZMLH presented a deterioration of accuracy in comparison to ZMLC (P ≤ .001 to .008). The influence of highspeed sintering on marginal and general fit was not clinically relevant (P = .154 to .877).

Conclusion: High-speed sintering influenced the accuracy of 4Y-TZP full-coverage single-unit and three-unit FDPs. However, no clinically relevant impact on fit was observed.
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http://dx.doi.org/10.11607/ijp.7428DOI Listing
February 2021

Edge chipping resistance of veneering composite resins.

J Mech Behav Biomed Mater 2021 04 2;116:104349. Epub 2021 Feb 2.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany. Electronic address:

Objectives: To investigate the edge chipping resistance (ECR) of six veneering composite resins after different treatment protocols.

Materials And Methods: Rectangular bar specimens were manufactured from Ceramage Incisal (CER; Shofu), dialog Vario Occlusal (DIA; Schütz Dental), Gradia Plus Heavy Body Enamel (GRA; GC Europe), in:joy incisal (INJ; Dentsply Sirona Deutschland), SR Nexco Paste Incisal (SRN; Ivoclar Vivadent), and Signum composite enamel (SIG; Kulzer). ECR was determined after five treatment protocols: (1) no treatment, (2) after storage in distilled water at 37 °C for 7 days, (3) storage in distilled water with an additional 10 000 thermal cycles (5 °C/55 °C), and hydrothermal treatment at 134 °C at a water vapor pressure of 0.2 MPa for a duration of (4) 3.5 min or (5) 23.5 min. Force was applied with the universal testing machine ZHU 0.2 (Zwick Roell) mounted with a Vickers diamond indenter until the chip fractured off the specimen and ECR values were computed by dividing the applied maximum force by the distance to the center of the applied force. Fracture analysis was performed employing light microscope imaging. Univariate and one-way ANOVA, Scheffé and Tukey-B post hoc, and partial eta squared (ƞ) were computed (p < 0.05).

Results: DIA presented consistently high ECR values, while CER showed low results. For some groups, seven days' storage in water and hydrothermal treatment for 3.5 min led to higher ECR results than observed in the initial state, while an additional 10 000 thermal cycles and hydrothermal treatment for 23.5 min resulted in lower ECR values.

Conclusions: The examined veneering composite resins differed in regard to their mechanical properties, with DIA possessing the highest resistance to chipping. While post-processing can initially increase a material's edge chipping resistance, intensified treatment protocols reduced the mechanical properties of veneering composite resins.
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http://dx.doi.org/10.1016/j.jmbbm.2021.104349DOI Listing
April 2021

Impact of polymerization and storage on the degree of conversion and mechanical properties of veneering resin composites.

Dent Mater J 2021 Mar 18;40(2):487-497. Epub 2020 Dec 18.

Department of Prosthetic Dentistry, University Hospital, LMU Munich.

To investigate the degree of conversion (DC), Martens hardness (HM), elastic indentation modulus (E), and flexural strength (FS) of veneering resin composites (SR Nexco Paste (NP), Ceramage Incisal (CI), Gradia Plus (GP); n=60/group) cured with different polymerization devices (bre.Lux Power Unit, Labolight DUO, Otoflash G171, LC-3DPrint Box, PCU LED; n=12/subgroup) after storage. Otoflash G171 and Labolight DUO showed increased DC/HM/E. CI presented the lowest DC and highest HM/E. NP showed the highest DC and lowest HM/E. Within Otoflash G171, Laboligth DUO and PCU LED, highest FS was observed for CI. Storage did not affect DC/HM/E for specimens cured with Otoflash G171 or Labolight DUO. With storage not showing an influence on the tested parameters for polymerization devices that otherwise presented superior results, increased storage time cannot be recommended. For the tested resin composites, this study observed a high/low degree of conversion to coincide with respectively low/high amounts of fillers/mechanical properties.
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http://dx.doi.org/10.4012/dmj.2019-394DOI Listing
March 2021

Mechanical and optical properties of indirect veneering resin composites after different aging regimes.

Dent Mater J 2021 Mar 19;40(2):279-287. Epub 2020 Nov 19.

Department of Prosthetic Dentistry, University Hospital.

This study tested and compared properties of six modern indirect veneering resin composites (VRC), namely Ceramage (Shofu), dialog Vario (Schütz Dental), Gradia Plus (GC Europe), in:joy (Dentsply), Signum composite (Heraeus Kulzer), and SR Nexco (Ivoclar Vivadent). Specimens were fabricated from dentin and enamel pastes and following properties were analyzed: (1) two-body wear (TB), (2) surface roughness (SR), (3) Martens hardness parameters (HM and E), and (4) translucency (T). The highest impact on HM and E was exerted by VRC brand (HM: η=0.960/ E: η=0.968; p<0.001), followed by VRC paste material (HM: η=0.502/ E: η=0.580; p<0.001), and aging duration (HM: η=0.157/ E: η=0.112; p<0.001). Lowest and highest TB were measured for Signum composite and dialog Vario, respectively (p<0.001). Highest T was showed Signum composite and Ceramage (p<0.001). VRCs should be individually selected with respect to the indication area, due to different surface properties.
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http://dx.doi.org/10.4012/dmj.2019-307DOI Listing
March 2021

Development and evaluation of an interdisciplinary teaching model via 3D printing.

Clin Exp Dent Res 2021 Feb 27;7(1):3-10. Epub 2020 Oct 27.

Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University, Munich, Germany.

The investigation aimed to assess the feasibility of creating an interdisciplinary training model simulating endodontic, restorative as well as implantologic treatment procedures by using 3D printing technology. A CBCT scan of the mandible of a real patient was initially taken. The generated DICOM-data were converted to a STL-file, which was further processed to design spaces for exchangeable replica teeth, a bone segment and an adapter to fix the model in a mannequin's head. After the manufacturing process, the model was evaluated by dental students performing a root canal treatment, the insertion of a glass fibre post and the insertion of an implant. The workflow allowed a simple and cost-effective way of manufacturing a single model, which is suitable for several training scenarios in the fields of endodontics, prosthodontics and implantology. The model was rated as being comparable to the real patient situation and offers repetitive treatment simulations. The present workflow is a feasible way of using DICOM-data and 3D printing for an interdisciplinary training model. The dental schools can design models according to their own curriculum and put the focus on a patient centered education.
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http://dx.doi.org/10.1002/cre2.334DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7853885PMC
February 2021

Oral health-related impact profile of patients treated with fixed, removable, and telescopic dental prostheses in student courses-a prospective bicenter clinical trial.

Clin Oral Investig 2021 Apr 27;25(4):2191-2201. Epub 2020 Aug 27.

Department of Prosthetic Dentistry, Würzburg, Germany.

Objectives: To analyze the oral health-related impact profile in patients treated with three different types of dental prosthesis in student courses.

Materials And Methods: This prospective bicenter clinical trial was conducted with 151 patients being treated with fixed (n = 70), removable (n = 61), or telescopic dental prostheses (n = 20) in clinical student courses of two German universities from October 2018 to October 2019. All patients completed three standardized German versions of the Oral Health Impact Profile (OHIP-G49/53) before prosthetic treatment (T0), at control after 1 week (T1), and after 3 months (T2), divided into five dimensions: (a) appearance, (b) oral function, (c) psychosocial impact, (d) linguistic limitations, and (e) orofacial pain. Data were analyzed with Kolmogorov-Smirnov, Wilcoxon signed-rank, Kruskal-Wallis, Mann-Whitney, and Cronbach's alpha tests.

Results: Within T0-T1 and T0-T2, greater improvements were determined for removable compared with fixed dental prostheses for the dimensions' oral function (p ≤ 0.014), linguistic limitations (p ≤ 0.016), and appearance (p ≤ 0.003). No significant differences were found between fixed and telescopic dental prostheses (p ≥ 0.104) or between removable (partial dental prosthesis with clasps and complete dental prosthesis) and telescopic dental prostheses (p ≥ 0.100). Within T1-T2, a significant improvement in orofacial pain could be determined (p = 0.007).

Conclusions: Restorations presented an improvement in oral health-related quality of life. Removable dental prostheses showed better improvement than fixed ones in various dimensions.

Clinical Relevance: Knowledge about the influence of oral health-related quality of life on the three different types of prosthesis used in student courses can be of decisive help in dental consultations.
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http://dx.doi.org/10.1007/s00784-020-03532-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7966221PMC
April 2021

Impact of thermocycling on mechanical properties and discoloration of veneering composite resins after storage in various staining media.

J Prosthet Dent 2021 Jun 2;125(6):940-945. Epub 2020 Jul 2.

Scientific Head of Dental Materials Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.

Statement Of Problem: Veneering composite resins (VCRs) are often used to veneer frameworks, but knowledge of mechanical, surface, and discoloring properties is scarce.

Purpose: The purpose of this in vitro study was to evaluate the impact of thermocycling on flexural strength (FS) and the influence of different staining media on the discoloration (ΔE) and surface free energy (SFE) of VCRs.

Material And Methods: The following VCRs were tested: Ceramage, dialog Vario, Gradia Plus, in:joy, Signum composite, and SR Nexco. FS was tested with enamel and dentin pastes (except SR Nexco: only enamel paste), whereas ΔE and SFE were analyzed for enamel pastes. ΔE was determined by using a spectrophotometer, and SFE was evaluated with contact angle measurements. For FS, rod-shaped specimens (N=660, n=10/subgroup; 25×2×2 mm) were fabricated, thermocycled for 220, 1500, 10 000, 20 000, and 40 000 cycles (5 °C/55 °C). and tested immediately after fabrication (initial) and after aging. For ΔE and SFE, disc-shaped specimens (N=300, n=10/subgroup; 15x15x1.4 mm) were fabricated and stored for 14 days in coffee, red wine, carrot juice, beetroot juice, or curry solution. ΔE and SFE were measured initially after polishing, after discoloration, and after repolishing. Data were analyzed using univariate analysis, 1-way ANOVA followed by the Scheffé post hoc test, Kolmogorov-Smirnov test, Kruskal-Wallis test, Mann-Whitney U test, and Wilcoxon test (α=.05).

Results: Ceramage had the highest FS, followed by dialog Vario and SR Nexco. Gradia Plus, and in:joy had the lowest FS, followed by Signum composite. FS was reduced by increasing of thermocycles. The highest ΔE was measured for curry and the lowest for carrot juice and red wine, followed by beetroot juice and coffee. The highest ΔE between the initial polished specimens and repolished specimens were observed for Ceramage. The remaining VCRs showed differences in ΔE between 0.95 (Signum composite) and 1.30 (SR Nexco). The SFE of the VCRs was similar. After storage in discoloring media, all VCRs had higher SFE than directly after polishing (initial). Repolishing decreased the SFE values compared with those of specimens measured after storage.

Conclusions: FS, ΔE, and SFE differed between the VCRs tested. Discoloration of the VCRs depended on the food and beverage and could be corrected to a clinically acceptable range by repolishing.
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http://dx.doi.org/10.1016/j.prosdent.2020.03.030DOI Listing
June 2021

Virtual education: Dental morphologies in a virtual teaching environment.

J Dent Educ 2020 Oct 8;84(10):1143-1150. Epub 2020 Jun 8.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.

Objectives: Digital technology is already playing an increasingly important role in the education of students. The present investigation examined the acceptance of preclinical students for learning dental morphologies in virtual reality (VR).

Methods: The creation of the VR dental teaching environment was divided into 3 sections: (a) generation of the digital data; (b) creation of the VR dental learning environment for tooth morphologies; and (c) evaluation by preclinical students through questionnaires combined with visual analogue scale and fixed-answer options. Students of the Department of Prosthetic Dentistry of the University Hospital Munich were able to stay/interact in the VR dental learning environment for 10 minutes with VR headsets and hand controllers. The data were analyzed using the Kolmogorov-Smirnov test and exploratory data analysis using the median value and interquartile range.

Results: Of the students, 34.9% stated that they understand dental morphologies much better, 57.1% better, and 7.9% equally well compared to using the traditional textbook. The students would be willing to spend about 500 euros privately for the VR equipment. The haptic and auditive teaching elements were evaluated more positively than the purely visual ones of the integrated information boards.

Conclusions: Learning in the VR dental learning environment showed a high level of acceptance among all students and should be integrated as a fixed element in the dental curriculum. A further development for use independent of time and place is desirable.
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http://dx.doi.org/10.1002/jdd.12235DOI Listing
October 2020

Impact of fabrication procedures on residual monomer elution of conventional polymethyl methacrylate (PMMA)-a measurement approach by UV/Vis spectrophotometry.

Clin Oral Investig 2020 Dec 18;24(12):4519-4530. Epub 2020 May 18.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany.

Objectives: To analyse the residual monomer (MMA) elution of polymethyl methacrylate (PMMA) in distilled water after diverse fabrication methods and aging procedures.

Materials And Methods: PMMA specimens (N = 192, PalaXpress; Kulzer, Hanau, Germany) were manufactured (pouring, n = 96/injection, n = 96) and polymerized in water (55°C) without pressure (n = 48) and with 2 bar pressure (n = 48). Specimens were grinded (n = 24) or polished (n = 24) and aged for 12 h in distilled water/37°C (n = 12) or at air/20°C (n = 12) and stored afterwards in distilled water at 37°C. MMA elution was evaluated after 1, 2, 3, 4, 5, 6, 7, 10, 15 days (UV/Vis spectrophotometry). Data were analysed with Kolmogorov-Smirnov, Mann-Whitney-U and Cohen-d test using SPSS (α < 0.5).

Results: The pouring procedure resulted in significantly higher MMA elution than the injection procedure up to 5 days. Polymerization with a pressure of 2 bar reduced the MMA elution significantly for poured specimens. Polishing reduced the MMA elution in comparison to grinding.

Conclusions: The fabrication procedure (pouring/injection) showed the strongest correlation to the MMA elution (r = 0.500), followed by polishing (r = 0.243), the pressure during polymerization (r = 0.109) and the storage medium (r = 0.053).

Clinical Relevance: Higher MMA elution may increase the risk of chemical irritations, allergic reactions and hypersensitivities of the oral mucosa. Technicians and dentists should be aware about the elution differences dependent on the fabrication procedure.
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http://dx.doi.org/10.1007/s00784-020-03317-1DOI Listing
December 2020

A pattern of care analysis: Prosthetic rehabilitation of head and neck cancer patients after radiotherapy.

Clin Implant Dent Relat Res 2020 Jun 29;22(3):333-341. Epub 2020 Apr 29.

Department of Radiation Oncology, University Hospital Zurich, University of Zurich, Zurich, Switzerland.

Background: While some medical associations provide guidelines for the implant-prosthetic rehabilitation of head and neck cancer patients, the circulation and implementation in the everyday routine of practicing dentists remain unknown.

Purpose: To analyze patterns of care for the prosthetic rehabilitation of head and neck cancer patients after radiotherapy in German speaking countries.

Materials And Methods: An online survey consisting of 34 questions separated into three sections, (a) general inquiries, (b) treatment concepts, and (c) patient cases, was forwarded to university hospital departments for Prosthetic Dentistry and Oral and Maxillofacial Surgery, and members of different medical associations. Statistical differences between groups were analyzed using chi-squared test (P < .05).

Results: From May to October 2019, 118 participants completed the survey. The majority practiced in university hospitals, had more than 5 years of work experience, and reported to be involved in <10 post radiation prosthetic rehabilitation cases per year. Rehabilitation protocols involving dental implants were implemented by oral/oral- and maxillofacial surgeons and prosthetic dentists, while general dentists favored implant-free solutions. Xerostomia was recognized as a common problem for a successful prosthetic rehabilitation. The subsequent treatment choice with either fixed dental prostheses or removable dentures was divided among participants.

Conclusions: As treatment planning differed with regard to the participants' field of expertise and work environment, and most practitioners only handle a low number of cases, patients might benefit from centralization in larger institutes with a multidisciplinary structure. A high agreement between the practitioners' treatment concepts and the current state of research was observed. While the choice between a mucosa- or tooth-supported, and an implant-supported restoration depends on numerous individual factors, guidelines derived from longitudinal studies would enhance evidence-based treatment in this field.
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http://dx.doi.org/10.1111/cid.12912DOI Listing
June 2020

Flexural strength, fracture toughness, three-body wear, and Martens parameters of pressable lithium-X-silicate ceramics.

Dent Mater 2020 03 30;36(3):420-430. Epub 2020 Jan 30.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany.

Objectives: To test and compare five pressable lithium-X-silicate-ceramics on their mechanical and wear properties.

Methods: Specimens were pressed and prepared from: i. Amber Press (AP), ii. Celtra Press (CP), iii. Initial LiSi Press (IL), iv. Livento Press (LP), and v. IPS e.max Press (IE). Four-point flexural strength (FS), SEVNB fracture toughness (K), three-body wear (3BW), Martens hardness (HM) and indentation modulus (E) were measured. For CP, FS and HM were measured with and without additional Power Firing. Each subgroup contained 15 specimens. Data were analyzed using Kolmogorov-Smirnov, one-way ANOVA followed by Scheffé test, Kruskal-Wallis-H-, Mann-Whitney-U-, and Spearman-Rho-test (p < 0.05). The Weibull modulus was calculated using the maximum likelihood estimation method.

Results: AP and CP presented higher FS than IL. LP presented the highest Weibull modulus. CP showed lower K values than AP, and AP was not significant compared to LP and IE. The most 3BW material loss was observed for CP. CP revealed higher HM values than the remaining ceramics. IL presented lower E compared to AP and CP. The following correlations were observed between the test parameters: 3BW with FS (r = 0.279, p = 0.015), with HM (r = -0.378, p = 0.001), and with E (r = -0.344, p = 0.004); E with FS (r = 0.203, p = 0.028); and HM with FT (r = -0.223, p = 0.027) and E (r = 0.884, p < 0.001). No correlations were observed between FS and K (r = 0.046; p = 0.346).

Significance: AP followed by LP showed the highest and IL followed by CP the lowest properties tested. Power Firing of CP improved the flexural strength. Ceramics with high flexural strength and Martens parameters showed lower wear. Materials with high Martens hardness presented lower fracture toughness values and ones with high indentation modulus showed high flexural strength.
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http://dx.doi.org/10.1016/j.dental.2020.01.009DOI Listing
March 2020

Clinical Performance of Anterior Full Veneer Restorations Made of Lithium Disilicate with a Mean Observation Time of 8 Years.

Int J Prosthodont 2020 Jan/Feb;33(1):14-21

Purpose: To evaluate the survival and complication rates of full veneer restorations after up to 11 years of clinical service.

Materials And Methods: Six patients (four men, two women, median age 42.3 ± 4.7 years) were restored with a total of 40 adhesively luted anterior full veneers (maxilla: 36; mandible: 6; mostly canine to canine) made of lithium disilicate ceramic. Patients were treated between July 2007 and January 2014. All restorations were examined during annual recall visits using the modified United States Public Health Service criteria for color match, marginal discoloration, secondary caries, marginal integrity, surface texture, and restoration fracture, rated as Alpha, Bravo, or Charlie. Data were statistically analyzed using Kaplan-Meier estimation with log-rank test.

Results: Time of clinical service was 68 to 139 months (median: 8.1 ± 2.0 years) without any dropouts. Full veneer restorations in the anterior dentition presented a survival rate of 100% and a complication rate of 12.5% due to reparable minor chippings (technical complication/restoration fracture rated Bravo) of four restorations (one after 11 months, one after 20 months, and two after 66 months) and a crack in one restoration (after 38 months) due to trauma. No further technical (debonding or discoloration) or biologic (secondary caries) complications occurred.

Conclusion: Based on the present results, minimally invasive anterior full veneer restorations might be considered as a reliable treatment option, but further clinical data are essential.
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http://dx.doi.org/10.11607/ijp.6465DOI Listing
December 2019

Flexural strength and fracture toughness of two different lithium disilicate ceramics.

Dent Mater J 2020 Mar 19;39(2):302-308. Epub 2019 Dec 19.

Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University Munich.

To test the impact of the pressing furnace on flexural strength and facture toughness of the lithium-disilicate-ceramics HS10PC (HS) and IPS e.max Press (IP). Three hundred and sixty specimens (3×4×30 mm) were pressed (n=180/ceramic) using different pressing furnaces, namely Austromat 654 Press-i-dent (AUS), Programat EP5000 (PRO), and Vario Press 300 (VAR). Three-point flexural strength (n=30) and fracture toughness (n=30) were measured. Flexural strength (336-360 MPa) was not affected by pressing furnace or ceramic and showed comparable values between all groups. Fracture toughness (2.65-2.81 MPa√m) provided higher values for HS pressed using AUS compared to specimens pressed in PRO and VAR. For IP, no impact of the pressing furnace on fracture toughness was found. IP presented higher fracture toughness than HS when pressed using PRO. No correlations were found. Both lithium disilicate ceramics showed comparable flexural strength regardless of the pressing furnace. Fracture toughness depended on the ceramic and on the pressing furnace.
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http://dx.doi.org/10.4012/dmj.2019-045DOI Listing
March 2020

Influence of Different Cleaning Procedures on Tensile Bond Strength Between Zirconia Abutment and Titanium Base.

Int J Oral Maxillofac Implants 2019 Nov/Dec;34(6):1318-1327

Purpose: To investigate the tensile bond strength between zirconia abutments and titanium bases, luted with two different resin composite cements, after different cleaning procedures.

Materials And Methods: Zirconia abutments and titanium bases were luted with either a DMA/HEMA-based cement (n = 80; Multilink Hybrid Abutment, Ivoclar Vivadent) or a Bis-GMA/TEGDMA-based cement (n = 80; Panavia V5, Kuraray Noritake). The adhesive gap of half of the specimens was polished (n = 40 per resin composite cement). Four separate specimens underwent roughness measurements and scanning electron microscopy. The specimens were divided into four groups (n = 10 per subgroup): (1) not cleaned, (2) cleaning in an ultrasonic bath, (3) cleaning in an autoclave, and (4) treatment with low-pressure plasma. The specimens were thermocycled (20,000×, 5°C/55°C), tensile bond strength was tested, and fracture types were analyzed. Data were examined using the Kolmogorov-Smirnov test, univariate ANOVA with additional partial eta-squared (η), and the Mann-Whitney U test. The defined level of significance was adjusted by Bonferroni correction (P < .003).

Results: The tensile bond strength of specimens luted with the DMA/HEMA-based cement was higher than that of specimens luted with the Bis-GMA/TEGDMA-based cement. The polishing step and the cleaning procedures showed no impact on tensile bond strength results. Specimens luted with the DMA/HEMA-based cement presented more cohesive fractures, whereas specimens luted with the Bis-GMA/TEGDMA-based cement presented themselves with more fractures of the interface between the resin composite cement and zirconia abutment. R values showed a decline in roughness after polishing for both resin composite cements.

Conclusion: As the DMA/HEMA-based cement showed higher tensile bond strength values, the usage of this resin composite cement for luting implant abutments to titanium bases can be recommended. Neither polishing nor the use of different cleaning procedures had an impact on tensile bond strength.
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http://dx.doi.org/10.11607/jomi.7638DOI Listing
December 2019

Impact of storage media and temperature on color stability of tooth-colored CAD/CAM materials for final restorations.

J Appl Biomater Funct Mater 2019 Oct-Dec;17(4):2280800019836832

Department of Prosthetic Dentistry, LMU Munich, Munich, Germany.

Background: This in-vitro study examined the impact of storage solution, storage duration, and storage temperature on discoloration of three tooth-colored CAD/CAM materials for final restorations.

Methods: Specimens ( = 288; = 96 per material) with a thickness of 1 ± 0.03 mm of the following CAD/CAM materials were fabricated: resin composite (Lava Ultimate, 3M), polymer-infiltrated ceramic (VITA Enamic, VITA Zahnfabrik), and leucite ceramic (IPS Empress CAD, Ivoclar Vivadent). After baseline measurement, specimens were stored in red wine, curry solution, cress solution, and distilled water at 37°C or 55°C. The discoloration was measured using a spectrophotometer (Lambda 35 Perkin Elmer, Perkin Elmer Inc.) after 1 and 7 days storage. Data were analyzed using four-way ANOVA followed by the Scheffé post-hoc test and partial eta squared (²) test ( < 0.05).

Results: The highest influence on ∆ was exerted by storage duration (² = 0.295, < 0.001), followed by storage solution (² = 0.171, < 0.001), CAD/CAM material (² = 0.049, < 0.001), and storage temperature (² = 0.033, < 0.001). Specimens stored for 7 days in staining solutions showed more discoloration than those stored for just 1 day. Higher ∆ values were achieved for specimens stored in curry solution, followed by red wine, cress solution, and distilled water. Resin composite Lava Ultimate showed larger ∆ values compared with the resin hybrid ceramic VITA Enamic and leucite ceramic IPS Empress CAD. Specimens stored at 37°C showed significantly less discoloration than those stored at 55°C.

Conclusions: The degree of coloration of the materials depends on food and temperature and was most pronounced with Lava Ultimate.
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http://dx.doi.org/10.1177/2280800019836832DOI Listing
May 2020

Zirconia and its novel compositions: What do clinicians need to know?

Quintessence Int 2019 ;50(7):512-520

For several years, there has been a clear trend in the dental market towards monolithic tooth-colored restorations. In this context, further developments, particularly in the field of zirconia ceramics, have led to considerable improvement in the materials' optical properties. Modern zirconia materials can be divided into several cohorts, differing from each other with respect to their optical and mechanical properties. The knowledge about indications and limitations of each zirconia cohort is essential for a correct clinical application. Clinical long-term experience for the zirconia of the newest generations is still scarce and only in-vitro data are available. Despite all advancements, clinical long-term success remains closely linked to the specific indications, preparation, material selection, knowledge, and experience of the dental practitioner and dental technician, as well as an adequate luting mode and occlusal concept. Due to the high innovation rate within materials and CAD/CAM technology in general, clinicians and dental technicians need to be well informed in order to be able to work successfully with the various options.
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http://dx.doi.org/10.3290/j.qi.a42653DOI Listing
November 2019

Residual monomer elution from different conventional and CAD/CAM dental polymers during artificial aging.

Clin Oral Investig 2020 Jan 16;24(1):277-284. Epub 2019 May 16.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany.

Objectives: Analyze and quantify the residual monomer elution of nine conventional and CAD/CAM (computer-aided design/computer-aided manufacturing) dental polymers during artificial aging.

Materials And Methods: A total of 360 square-shaped specimens (14 × 12 × 2 ± 0.05 mm) were fabricated from eight CAD/CAM polymer blanks (n = 40): Avadent Base material, Avadent Teeth material, PMMA Multi blank, PMMA Mono blank, Temp Premium, Telio CAD, Ceramill Temp, Shofu Block HC, and conventional polymer PalaXpress. Specimens were aged in distilled water for 60 days at 37 °C and the evaluation of the residual monomer elution was made through UV spectrophotometry. Statistical analysis was carried out in the SPSS software. One-way ANOVA and Scheffé post hoc test were applied (α < 0.05).

Results: Aging time significantly changed the elution in all groups, except for PalaXpress. Statistically significant differences of elution were found between the materials. Shofu Block HC presented the highest, whereas PMMA Multi blank A3 and Mono blank A1 presented the lowest elution after the 60th day of aging.

Conclusions: CAD/CAM dental polymers as well as the conventional polymer PalaXpress eluted residual monomer within aging time. The differences in elution were material-dependent; still, the maximum elution found is below the specified threshold of ISO standard 20795-1.

Clinical Relevance: With the evolution of CAD/CAM technology, material's manufacturers have invested in the development of polymeric materials with higher resistance and stability to produce indirect restorations using CAD/CAM. It is expected that these materials present lower elution of residual monomer than conventional polymers.
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http://dx.doi.org/10.1007/s00784-019-02947-4DOI Listing
January 2020

Effect of Astringent Products on Accuracy of Polyether Impressions and Plaster Casts.

Int J Prosthodont 2019 May/Jun;32(3):281-288

Purpose: To investigate whether hemostatic agents have any detrimental effects on polyether impressions and plaster casts after a clinically viable cleaning protocol.

Materials And Methods: A total of 60 human molar teeth were manually standardized, prepared, and subdivided into five groups (G): G0 (control/no contamination); G1 (ViscoStat Clear); G2 (ViscoStat); G3 (Astringedent); and G4 (Astringedent X). Each tooth was contaminated with a hemostatic agent for 3 minutes and cleaned with a 30-second air/water spray. Before and after contamination, an impression was taken and a plaster cast was poured. The impressions and plaster casts of all teeth were scanned using a light scanner. Data were matched using a three-dimensional analysis software that displayed color-coded maps. Means of the maximum positive/negative values and of the mean deviations in each group were calculated and compared. All color-coded maps were interpreted descriptively using the program's color scale, and all impressions and plaster casts were microscopically evaluated.

Results: Values of mean deviations throughout all matched scans showed maximum values ranging from -30.1 to +17.5 μm. None of the groups showed significantly different deviation values or patterns when compared to each other. Impressions showed a thin, discontinuous coating for G2, G3, and G4; no changes were found for plaster casts.

Conclusion: Presented deviations showed the same values and distribution patterns within all groups. A cleaning protocol of 30 seconds of air/water spray is sufficient to remove hemostatic agents, preventing effects to polyether impressions and plaster casts. However, ferric sulfate-containing hemostatic agents left discontinuous coatings on impression surfaces.
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http://dx.doi.org/10.11607/ijp.6148DOI Listing
October 2019

The Effect of Hemostatic Agents on the Retention Strength of Zirconia Crowns Luted to Dentin Abutments.

Materials (Basel) 2019 Mar 25;12(6). Epub 2019 Mar 25.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany.

The purpose of this study was to investigate whether hemostatic agents (HA) show an effect on the retention strength (RS) of zirconia crowns luted to dentin abutments after cleaning with an air/water spray. Human molars (N = 60/n = 12) were prepared and zirconia crowns were milled. Prior to luting (Scotchbond Universal/RelyX Ultimate), molars were pretreated using HA: i. 25% AlCl₃ (VSC), ii. 20% Fe₂(SO₄)₃ (VS), iii. 15.5% Fe₂(SO₄)₃ (AS), iv. 12.7% iron ion solution (ASX) and v. no pretreatment (control). Mastication simulation and pull-out tests were performed. Failure types were defined: cohesive 1-tooth root; cohesive 2-tooth crown; adhesive 1-cement on tooth; adhesive 2-cement on tooth and crown; mixed-adhesive/cohesive. Data were analyzed using 1-way ANOVA, post-hoc Scheffé, Pearson's chi-square-test and Ciba⁻Geigy table (p = 0.05). No RS differences between the tested groups were observed (p = 0.200). ASX fractured more cohesive 2 than the control group. VSC showed more cohesive 2 than adhesive 1 fractures. VS showed more adhesive 2 than mixed fractures. AS showed more cohesive 2 than adhesive 1 and more adhesive 2 than mixed fractures. ASX showed predominantly cohesive 2 fractures. RS was not affected when HA were cleaned off by 30 s of air/water spray prior to luting. HA still seem to weaken the dentin abutment, making it prone to cohesive fractures.
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http://dx.doi.org/10.3390/ma12060979DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6471257PMC
March 2019

Interdisciplinary full-mouth rehabilitation for redefining esthetics, function, and orofacial harmony.

J Esthet Restor Dent 2019 05 4;31(3):179-189. Epub 2019 Jan 4.

Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.

Objective: In severe congenital or acquired orofacial anomalies, both dental esthetics and function are usually compromised. In particular, the esthetic ideas of the final desired appearance may differ from patient to patient, as the human esthetic sensibility differs significantly. Especially in complex cases, digital technology today offers outstanding improvements and simplifications in craniomaxillofacial surgical and prosthetic treatments, leading to a wide range of planning and pretreatment options.

Clinical Considerations: This case report describes a patient-oriented interdisciplinary craniomaxillofacial surgical and prosthetic treatment with noninvasive tooth-colored splints, a Le Fort I osteotomy, and a full-mouth rehabilitation to meet the patient's demand for better function as well as orofacial esthetics and harmony.

Conclusions: By means of the digitally planned Le Fort I intervention and completion of the prosthetic rehabilitation, it was possible to optimize esthetics and facial harmony.

Clinical Significance: In complex cases, digital technology today offers outstanding improvements and simplifications in craniomaxillofacial surgery and prosthetic treatments, leading to a wide range of planning and pretreatment options. Computer-aided design/computer-aided manufacturing technology enables the fabrication of tooth-colored flexible polycarbonate splints that offer a noninvasive, removable, functional, and esthetic solution. In intricate cases involving craniomaxillofacial anomalies, often together with necessary orofacial surgeries or prosthetic treatments due to moderate to severe tooth wear, such digital preprosthetic treatment and planning options represent an important enhancement with more predictable results.
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http://dx.doi.org/10.1111/jerd.12455DOI Listing
May 2019

Computable translucency as a function of thickness in a multi-layered zirconia.

J Prosthet Dent 2019 Apr 4;121(4):683-689. Epub 2018 Dec 4.

CDT, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany.

Statement Of Problem: Determining the relationship between variable thicknesses and the translucency of dental ceramics is essential for optimizing esthetics in different clinical situations.

Purpose: The purpose of this in vitro study was to analyze the relationship between layer thickness and translucency of 2 multi-layered monolithic zirconia materials and to develop an equation by which the grade of translucency can be calculated dependent on the materials' layer thicknesses in advance.

Material And Methods: Two semisintered multi-layered zirconia blanks, namely KATANA Zirconia Super Translucent Multi-Layered Disk (Noritake Dental Supply Co, Ltd) and Zirconia Ultra Translucent Multi-Layered Disk (UTML) (Noritake Dental Supply Co, Ltd), were sectioned (N=96) to separate the 4 layers (n=12 per layer): enamel layer, transition layer 1, transition layer 2, body layer. All specimens were sintered in a furnace (M2 Plus; Thermo-Star) at 1500°C for 2 hours and automatically polished under water cooling up to P2400 for the thicknesses of 1.6, 1.3, 1.0, 0.7, and 0.4 mm. Transmittance of visible light was measured using a spectrophotometer (Lambda 35; Perkin Elmer). Data were analyzed using the Kolmogorov-Smirnov, 2-way ANOVA, and Scheffé post hoc tests (α=.01) and curve fitting.

Results: Analyzing the fitting of the values of the 8 material groups to the linear, exponential, and logarithmic curves, 7 of the 8 groups (not UTML body layer) fitted the most (R-square value closer to 1.0) to the logarithmic curve. Constants were obtained from the distance to the x-axis and the curvature.

Conclusions: The methodology of this study provided the materials' specific constants a and b by analyzing the translucency behavior of KATANA Super Translucent Multi-Layered Disk and Ultra Translucent Multi-Layered Disk in different thicknesses, allowing further translucency calculation by applying the developed formula and the constants.
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http://dx.doi.org/10.1016/j.prosdent.2018.08.013DOI Listing
April 2019

A patient-calibrated individual wax-up as an essential tool for planning and creating a patient-oriented treatment concept for pathological tooth wear.

Int J Esthet Dent 2018 ;13(4):476-492

Tooth wear is generally a physiological process; however, it can also be a pathological condition associated with attrition, abrasion, and erosion processes in which the quantity of tooth loss is atypical for the patient's age. Tooth substance loss often causes functional problems, symptoms of discomfort/pain, and esthetic impairments. Patients presenting this condition frequently need restorative treatment, combined with an increase in the vertical dimension of occlusion (VDO). A diagnostic wax-up (DWU) provides assistance in determining a new occlusal plane and VDO, and is a fundamental tool considering the backward planning involved in the execution of a complex rehabilitation. In cases of severe tooth wear, preventive measures must be taken. Yet, when a restorative intervention is needed, the use of a DWU, in conjunction with a mock-up, helps to achieve a predictable and satisfactory outcome. This article presents a case report of a young female patient with pathological tooth wear, related symptomatology, and esthetic complaints. Initially, a DWU and a diagnostic mock-up were created. After esthetic and functional corrections, a second DWU was generated and transferred to the patient's mouth by means of a therapeutic mock-up. This mock-up was used as a trial restoration for the pretreatment phase, to evaluate the new VDO/esthetics/function and to guide tooth preparation. Lithium disilicate (LS2) occlusal onlays were used to stabilize the VDO, and anterior LS2 and feldspathic veneers, combined with direct composite restorations, were executed to reach the planned minimally invasive result.
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June 2019

Hemostatic gingival retraction agents and their impact on prosthodontic treatment steps: A narrative review.

Quintessence Int 2018 ;49(9):719-732

The purpose of this topic review is to give a general overview of gingival retraction agents used during prosthodontic treatment, and the possible difficulties connected to them that may be faced by the dentist. Hemostatic agents are important for successful gingival retraction and in achieving hemostasis. However, these agents may show numerous negative effects on the prosthodontic treatment and oral tissues of which the practicing dentist must be aware, and which will be elucidated in this review. PubMed and Google Scholar databases were searched for publications up to and including 2017. The following key words were used in different combinations: "hemostatic agent," "astringent," "astringency," "epinephrine," "ferric sulfate," "aluminum chloride," "hemorrhage control," "soft tissue," "hard dental tissue," "self-etch adhesive," "total-etch adhesive," "bond strength," "impression," "gypsum," "plaster cast," and "dental cast." In the last three decades the hemostatic agents used by practicing dentists have changed from epinephrine towards astringents, with AlCl3 and Fe2(SO4)3 now the most popular. All of the currently known hemostatic agents cause some local, temporary gingival tissue damage, but only epinephrine is known to elicit negative systemic effects. Studies concerning the influence of hemostatic agents on impression materials show highly contradictory results regarding the possible polymerization-inhibiting properties of hemostatic agents, probably due to the lack of standardization of methodology. Hemostatic agents seem to alter the dentinal surface properties making it more resistant to acid etching. Therefore the relatively low acidity of self-etch adhesives when compared to total-etch systems may not be strong enough to sufficiently etch a more resistant dentinal surface, and consequently may result in lower adhesive bond strengths.
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http://dx.doi.org/10.3290/j.qi.a41010DOI Listing
March 2019