Robert Alexander Sader

Prof. Dr. Robert Alexander Sader


Research Focus & Metrics

Academic Career Length

30Years (1997-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 May 2024 in International Journal of Implant Dentistry
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PGPeter Gehrke
Peter Gehrke
MRMahsa Rashidpour
Mahsa Rashidpour
RSRobert Alexander Sader
Robert Alexander Sader
PWPaul Weigl
Paul Weigl
Purpose: The purpose of this systematic review was to explore and identify the factors that influence the accuracy of intraoral scanning in implant dentistry, with a specific focus on scan bodies (ISBs). Methods: Following the PRISMA 2020 guidelines, this study conducted a thorough electronic search across MedLine, PubMed, and Scopus to identify relevant studies. Articles were screened based on titles, abstracts, and full texts for relevance. The Robins I tool assessed the risk of bias in various study types. Data extraction occurred based on predetermined parameters for studying specimens and assessing outcomes. Results: 16 studies met the specified criteria and were consequently included in the systematic review. Due to variations in variables and methods across the selected studies, statistical comparison of results was not feasible. Therefore, a descriptive review approach was chosen, acknowledging the substantial heterogeneity in the reviewed literature. Conclusions: The precision of virtual scan results is contingent upon diverse characteristics of ISBs and implants. These factors encompass their placement within the dental arch, structural design, shape, material composition, color, and the manufacturing system, all of which contribute to scan accuracy. Additionally, considerations such as the intraoral scanner (IOS) type, scanning technique, use of scan aids, inter-implant distance, scan span, and the number of implants warrant evaluation. In the context of capturing implant positions, intraoral scanning with ISBs demonstrates comparable accuracy to traditional impression methods, particularly in single and short-span scenarios. However, the existing data lacks sufficient information on in vivo applications to formulate clinical recommendations.

15 September 2014 in Head & Face Medicine
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IWInes Willershausen
Ines Willershausen
Thomas Gerhard WolfThomas Gerhard Wolf
Thomas Gerhard Wolf
VWVeronika Weyer
Veronika Weyer
RSRobert Alexander Sader
Robert Alexander Sader
SGShahram Ghanaati
Shahram Ghanaati
BWBrita Willershausen
Brita Willershausen
Over the last years, electronic cigarettes (ECs) have become more popular, particularly in individuals who want to give up smoking tobacco. The aim of the present study was to assess the influence of the different e-smoking liquids on the viability and proliferation of human periodontal ligament fibroblasts. For this study six test solutions with components from ECs were selected: lime-, hazelnut- and menthol-flavored liquids, nicotine, propylene glycol, and PBS as control group. The fibroblasts were incubated up to 96 h with the different liquids, and cell viability was measured by using the PrestoBlue® reagent, the ATP detection and the migration assay. Fluorescence staining was carried out to visualize cell growth and morphology. Data were statistically analyzed by two-tailed one-way ANOVA. The cell viability assay showed that the proliferation rates of the cells incubated with nicotine or the various flavored liquids of the e-cigarettes were reduced in comparison to the controls, though not all reductions were statistically significant. After an incubation of 96 h with the menthol-flavored liquid the fibroblasts were statistically significant reduced (p < 0.001). Similar results were found for the detection of ATP in fibroblasts; the incubation with menthol-flavored liquids (p < 0.001) led to a statistically significant reduction. The cell visualization tests confirmed these findings. Within its limits, the present in vitro study demonstrated that menthol additives of e-smoking have a harmful effect on human periodontal ligament fibroblasts. This might indicate that menthol additives should be avoided for e-cigarettes.

2 December 2019 in Materials
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SASarah Al-Maawi
Sarah Al-Maawi
CHCarlos Herrera-Vizcaíno
Carlos Herrera-Vizcaíno
AOAnna Orlowska
Anna Orlowska
IWInes Willershausen
Ines Willershausen
RSRobert Alexander Sader
Robert Alexander Sader
Shahram GhanaatiShahram Ghanaati
Shahram Ghanaati
Platelet-rich fibrin (PRF) is a blood concentrate derived from venous blood that is processed without anticoagulants by a one-step centrifugation process. This three-dimensional scaffold contains inflammatory cells and plasma proteins entrapped in a fibrin matrix. Liquid-PRF was developed based on the previously described low-speed centrifuge concept (LSCC), which allowed the introduction of a liquid-PRF formulation of fibrinogen and thrombin prior to its conversion to fibrin. Liquid-PRF was introduced to meet the clinical demand for combination with biomaterials in a clinically applicable and easy-to-use way. The aim of the present study was to evaluate, ex vivo, the interaction of the liquid-PRF constituents with five different collagen biomaterials by histological analyses. The results first demonstrated that large variability existed between the biomaterials investigated. Liquid-PRF was able to completely invade Mucograft® (MG; Geistlich Biomaterials, Wolhusen, Switzerland) and to partly invade Bio-Gide® (BG; Geistlich Biomaterials, Wolhusen, Switzerland) and Mucoderm® (MD; Botiss Biomaterials, Berlin, Germany), and Collprotect® (CP; Botiss Biomaterials, Berlin, Germany) showed only a superficial interaction. The BEGO® collagen membrane (BCM; BEGO Implant Systems) appeared to be completely free of liquid-PRF. These results were confirmed by the different cellular penetration and liquid-PRF absorption coefficient (PAC) values of the evaluated membranes. The present study demonstrates a system for loading biomaterials with a complex autologous cell system (liquid-PRF) in a relatively short period of time and in a clinically relevant manner. The combination of biomaterials with liquid-PRF may be clinically utilized to enhance the bioactivity of collagen-based biomaterials and may act as a biomaterial-based growth factor delivery system.

5 March 2012 in Head & Face Medicine
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PSPD Dr. Dr. Markus Schlee
PD Dr. Dr. Markus Schlee
SGShahram Ghanaati
Shahram Ghanaati
IWInes Willershausen
Ines Willershausen
MSMichael Stimmlmayr
Michael Stimmlmayr
Anton SculeanAnton Sculean
Anton Sculean
RSRobert Alexander Sader
Robert Alexander Sader
The aim of this study was to clinically assess the capacity of a novel bovine pericardium based, non-cross linked collagen matrix in root coverage.

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SASarah Al-Maawi
Sarah Al-Maawi
EDEva Dohle
Eva Dohle
Jing LimJing Lim
Jing Lim
PWPaul Weigl
Paul Weigl
Swee Hin TeohSwee Hin Teoh
Swee Hin Teoh
Shahram GhanaatiShahram Ghanaati
Shahram Ghanaati
Introduction: Resorbable synthetic scaffolds are promising for different indications, especially in the context of bone regeneration. However, they require additional biological components to enhance their osteogenic potential. In addition to different cell types, autologous blood-derived matrices offer many advantages to enhance the regenerative capacity of biomaterials. The present study aimed to analyze whether biologization of a PCL-mesh coated using differently centrifuged Platelet rich fibrin (PRF) matrices will have a positive influence on primary human osteoblasts activity in vitro. A polymeric resorbable scaffold (Osteomesh, OsteoporeTM (OP), Singapore) was combined with differently centrifuged PRF matrices to evaluate the additional influence of this biologization concept on bone regeneration in vitro. Peripheral blood of three healthy donors was used to gain PRF matrices centrifuged either at High (710× g, 8 min) or Low (44× g, 8 min) relative centrifugal force (RCF) according to the low speed centrifugation concept (LSCC). OP-PRF constructs were cultured with pOBs. POBs cultured on the uncoated OP served as a control. After three and seven days of cultivation, cell culture supernatants were collected to analyze the pOBs activity by determining the concentrations of VEGF, TGF-β1, PDGF, OPG, IL-8, and ALP- activity. Immunofluorescence staining was used to evaluate the Osteopontin expression of pOBs. After three days, the group of OP+PRFLow+pOBs showed significantly higher expression of IL-8, TGF-ß1, PDGF, and VEGF compared to the group of OP+PRFHigh+pOBs and OP+pOBs. Similar results were observed on day 7. Moreover, OP+PRFLow+pOBs exhibited significantly higher activity of ALP compared to OP+PRFHigh+pOBs and OP+pOBs. Immunofluorescence staining showed a higher number of pOBs adherent to OP+PRFLow+pOBs compared to the groups OP+PRFHigh+pOBs and OP+pOBs. To the best of our knowledge, this study is the first to investigate the osteoblasts activity when cultured on a PRF-coated PCL-mesh in vitro. The presented results suggest that PRFLow centrifuged according to LSCC exhibits autologous blood cells and growth factors, seem to have a significant effect on osteogenesis. Thereby, the combination of OP with PRFLow showed promising results to support bone regeneration. Further in vivo studies are required to verify the results and carry out potential results for clinical translation.

1 September 2019 in Archives of Plastic Surgery
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SKShafreena Kühn
Shafreena Kühn
SKSeirah Keval
Seirah Keval
RSRobert Alexander Sader
Robert Alexander Sader
LKLara Küenzlen
Lara Küenzlen
MKMarcus Kiehlmann
Marcus Kiehlmann
URUlrich Michael Rieger
Ulrich Michael Rieger
Background Mastectomy in male transgender patients is an important (and often the first) step toward physical manhood. At our department, mastectomies in transgender patients have been performed for several decades. Methods Recorded data were collected and analyzed for all male transgender patients undergoing mastectomy over a period of 24 years at our department. Results In total, 268 gender-reassigning mastectomies were performed. Several different mastectomy techniques (areolar incision, n=172; sub-mammary incision, n=96) were used according to patients’ habitus and breast features. Corresponding to algorithms presented in the current literature, certain breast qualities were matched with a particular mastectomy technique. Overall, small breasts with marginal ptosis and good skin elasticity allowed small areolar incisions as a method of access for glandular removal. In contrast, large breasts and those with heavy ptosis or poor skin elasticity often required larger incisions for breast amputation. The secondary correction rate (38%) was high for gender reassignment mastectomy, as is also reflected by data in the current literature. Secondary correction frequently involved revision of chest wall recontouring, suggesting inadequate removal of the mammary tissue, as well as scar revision, which may reflect intense traction during wound healing (36%). Secondary corrections were performed more often after using small areolar incision techniques (48%) than after using large sub-mammary incisions (21%). Conclusions Choosing the suitable mastectomy technique for each patient requires careful individual evaluation of breast features such as size, degree of ptosis, and skin elasticity in order to maximize patient satisfaction and minimize secondary revisions.