Ralph Steegman

Mr. Ralph Steegman


Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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1 September 2020 in Colloids and Surfaces B: Biointerfaces
Verified
Journal Article
Open access
YWYanyan Wu
Yanyan Wu
HMHenny C. Van der Mei
Henny C. Van der Mei
HBHenk J. Busscher
Henk J. Busscher
RSRalph Steegman
Ralph Steegman
Alternatives for less and less effective antibiotic treatment of bacterial infections, are amongst others based on nanotechnological innovations, like carbon-dots. However, with a focus on chemistry, important characteristics of bacterial strains, like (in-)ability to produce extracellular-polymeric-substances (EPS) are often neglected. EPS is the glue that certain bacterial strains produce to keep a biofilm together. Here we report on synthesis of novel, pH-responsive, 2,3-dimethylmaleic-anhydride modified carbon-dots (CDMMA-dots). CDMMA-dots, like unmodified C-dots without DMMA, were little bactericidal. However, CDMMA-dots reduced volumetric-bacterial-density within the acidic-environment of a biofilm for a non-EPS-producing Staphylococcus epidermidis strain, indicative for a more open structure. Such a structural disruption was not observed for an EPS-producing strain. Disrupted biofilms of the non-EPS-producing strain pre-exposed to CDMMA-dots at pH 5.0, were more amenable to vancomycin penetration and killing of their inhabitants than biofilms of EPS-producing-staphylococci. Herewith, we describe a new role of carbon-dots as synthetic disruptants of biofilm structure. It is a partial success story, identifying the challenge of making carbon-dots that act as a universal disruptant for biofilms of strains with different microbiological characteristics, most notably the ability to produce or not-produce EPS. Such carbon-dots, will enable more effective clinical treatment of bacterial infections combined with current antibiotics.

13 February 2021 in Journal of Clinical Medicine
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Journal Article
Open access
PDF file
RSRalph Steegman
Ralph Steegman
AMAnnemarlien Faye Klein Meulekamp
Annemarlien Faye Klein Meulekamp
ADArjan Jan Albert Dieters
Arjan Jan Albert Dieters
JJJohan Jansma
Johan Jansma
WMWicher J. van der Meer
Wicher J. van der Meer
YRYijin Ren
Yijin Ren
This prospective controlled trial aimed to evaluate the skeletal effect of 3.5-years bone anchored maxillary protraction (BAMP) in growing cleft subjects with a Class III malocclusion. Subjects and Method: Nineteen cleft patients (11.4 ± 0.7-years) were included from whom cone beam computed tomography (CBCT) scans were taken before the start of BAMP (T0), 1.5-years after (T1) and 3.5 y after (T2). Seventeen age- and malocclusion-matched, untreated cleft subjects with cephalograms available at T0 and T2 served as the control group. Three dimensional skeletal changes were measured qualitatively and quantitatively on CBCT scans. Two dimensional measurements were made on cephalograms. Results: Significant positive effects have been observed on the zygomaticomaxillary complex. Specifically, the A-point showed a displacement of 2.7 mm ± 0.9 mm from T0 to T2 (p < 0.05). A displacement of 3.8 mm ± 1.2 mm was observed in the zygoma regions (p < 0.05). On the cephalograms significant differences at T2 were observed between the BAMP and the control subjects in Wits, gonial angle, and overjet (p < 0.05), all in favor of the treatment of Class III malocclusion. The changes taking place in the two consecutive periods (ΔT1-T0, ΔT2-T1) did not differ, indicating that not only were the positive results from the first 1.5-years maintained, but continuous orthopedic effects were also achieved in the following 2-years. Conclusions: In conclusion, findings from the present prospective study with a 3.5-years follow-up provide the first evidence to support BAMP as an effective and reliable treatment option for growing cleft subjects with mild to moderate Class III malocclusion up to 15-years old.

19 September 2023 in Clinical Oral Investigations
Verified
Journal Article
Open access
PDF file
RSRalph Steegman
Ralph Steegman
ARAnne-Marie Renkema
Anne-Marie Renkema
ASAdriaan Schoeman
Adriaan Schoeman
Anne Marie Kuijpers-JagtmanAnne Marie Kuijpers-Jagtman
Anne Marie Kuijpers-Jagtman
YRYijin Ren
Yijin Ren
Objective: To provide a critical overview of the effect of various orthodontic and/or dentofacial orthopedic interventions on three-dimensional volumetric changes in the upper airway. Materials and methods: Four databases were searched for clinical studies concerning 3D volumetric assessments based on CBCT before and after orthodontics interventions. The quality of the studies was assessed using the quality assessment tool of the National Heart, Lung and Blood Institute. After the use of inclusion and exclusion criteria, the pre-and post-treatment volumes were used to visualize the effect of various orthodontics interventions. Results: A total of 48 studies were included in this review and none of which were RCTs. The quality of all included studies was assessed as medium. Overall, there is a tendency for an increase in airway volumes after various orthodontic interventions, except for studies concerning extraction therapy with fixed appliances in adults, in which both increases and decreases in airway volumes have been reported. Conclusion: Orthodontic treatment by growth modification and non-extraction therapy with fixed appliances, regardless of the malocclusion, generally showed positive effects on the airway volume. Orthodontic treatment in combination with extractions does not provide an unambiguous insight. A consensus on the methodology of the airway measurement and nomenclature is urgently needed in order to gain insight into the effect of different interventions on three-dimensional airway changes. Clinical relevance: Various orthodontic treatments do not negatively influence the upper airway volume. However, extraction therapy in adults should be chosen with caution, especially in subjects belonging to a group susceptible to airway obstruction.

Verified
Journal Article
Open access
PDF file
RSRalph Steegman
Ralph Steegman
AMAnnemarlien F. Klein Meulekamp
Annemarlien F. Klein Meulekamp
ARAnne-Marie Renkema
Anne-Marie Renkema
KJKrista I. Janssen
Krista I. Janssen
Anne Marie Kuijpers-JagtmanAnne Marie Kuijpers-Jagtman
Anne Marie Kuijpers-Jagtman
YRYijin Ren
Yijin Ren
Background: Bone-anchored maxillary protraction (BAMP) aims to correct midfacial deficiencies, with proven positive skeletal changes without potential unwanted side effects. However, the influence of BAMP treatment on facial soft tissues, particularly in subjects with complete unilateral cleft lip, alveolus, and palate (CUCLAP), remains unclear. Methods: This single-center longitudinal cohort study examined the effects of 1.5 years of BAMP treatment on facial soft tissues in growing subjects with complete unilateral cleft lip, alveolus, and palate. The sample consisted of 25 patients, age range 9.7 to 12.6 years. Three-dimensional surface models derived from CBCT scans were superimposed on stable structures of the anterior cranial base and on the occipital area posterior of the foramen magnum to assess three-dimensional changes due to growth and BAMP therapy. Results: The results revealed a moderate positive correlation (Pearson’s correlation coefficient from 0.203 to 0.560) between changes in hard tissue and soft tissue; some correlations were found to be weak (<0.300). Linear changes in soft tissue following BAMP were in the same direction as skeletal changes, showing downward, forward, and outward displacement. The only exception was in the vertical dimension. The lower facial third showed a slight but significant reduction, mainly in lip length (−1.2 mm), whereas the middle facial third showed a small increase (1.1 mm). Conclusions: It was concluded that during BAMP, soft tissue changes occur in the same direction as skeletal changes, although with a larger variability and less pronounced effects.


4 April 2022
Verified
Report
Open access
RSRalph Steegman
Ralph Steegman
ARAnne-Marie Renkema
Anne-Marie Renkema
HVHerman Verbeek
Herman Verbeek
ASAdriaan Schoeman
Adriaan Schoeman
Anne Marie Kuijpers-JagtmanAnne Marie Kuijpers-Jagtman
Anne Marie Kuijpers-Jagtman
YRYijin Ren
Yijin Ren
INPLASY202240017 Upper Airway Volumetric Changes on CBCT after Orthodontic Interventions: protocol for a systematic review Keywords: CBCT; Airway; Orthodontics; Dentofacial Orthopedics; Volumetric …