Accepted Manuscript Full length article A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties S. Mastrogiacomo, N. Güvener, W. Dou, H.S. Alghamdi, W.A. Camargo, J.G.O. Cremers, P.J.A. Borm, A. Heerschap, E. Oosterwijk, J.A. Jansen, X.F. Walboomers PII: DOI: Reference:
S1742-7061(17)30517-2 http://dx.doi.org/10.1016/j.actbio.2017.08.018 ACTBIO 5029
To appear in:
Acta Biomaterialia
Received Date: Revised Date: Accepted Date:
22 May 2017 12 July 2017 12 August 2017
Please cite this article as: Mastrogiacomo, S., Güvener, N., Dou, W., Alghamdi, H.S., Camargo, W.A., Cremers, J.G.O., Borm, P.J.A., Heerschap, A., Oosterwijk, E., Jansen, J.A., Walboomers, X.F., A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties, Acta Biomaterialia (2017), doi: http:// dx.doi.org/10.1016/j.actbio.2017.08.018
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Original Manuscript: Acta Biomaterialia A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties Mastrogiacomo S.1, Güvener N.2,3, Dou W.4, Alghamdi H.S.5, Camargo W.A.1, Cremers J.G.O.2, Borm P.J.A.2, Heerschap A.4, Oosterwijk E.6, Jansen J.A.1, Walboomers X.F.1* 1
Department of Biomaterials, Radboud
University Medical
Center,
Nijmegen,
the
Netherlands. 2
Nano4Imaging GmbH, Pauwelsstrasse 17, Aachen, Germany.
3
Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany.
4
Department of Radiology and Nuclear Medicine, Radboud University Medical Center,
Nijmegen, the Netherlands. 5
College of Dentistry Research Center, King Saud University, Riyadh, Saudi Arabia.
6
Department of Urology, Radboud University Medical Center, Nijmegen, the Netherlands.
Key words: CPC (calcium phosphate cement), DCA (dual contrast agent), BMP-2 (bone morphogenetic protein-2), MRI (magnetic resonance imaging), direct pulp capping. * Corresponding author. Tel.: +31 (0)615827220 / +31(0)243692932 E-mail address: [email protected]
ABSTRACT Different materials have been used for vital dental pulp treatment. Preferably a pulp capping agent should show appropriate biological performance, excellent handling properties, and a good imaging contrast. These features can be delivered into a single material through the combination of therapeutic and diagnostic agents (i.e. theranostic). Calcium phosphate based composites (CPCs) are potentially ideal candidate for pulp treatment, although poor imaging contrast and poor dentino-inductive properties are limiting their clinical use. In this study, a theranostic dental pulp capping agent was developed. First, imaging properties of the CPC were improved by using a core-shell structured dual contrast agent (csDCA) consisting of superparamagnetic iron oxide (SPIO) and colloidal gold, as MRI and CT contrast agent respectively. Second, biological properties were implemented by using a dentinogenic
factor
(i.e.
bone
morphogenetic
protein
2,
BMP-2).
The
obtained
CPC/csDCA/BMP-2 composite was tested in vivo, as direct pulp capping agent, in a male Habsi goat incisor model. Our outcomes showed no relevant alteration of the handling and mechanical properties (e.g. setting time, injectability, and compressive strength) by the incorporation of csDCA particles. In vivo results proved MRI contrast enhancement up to 7 weeks. Incisors treated with BMP-2 showed improved tertiary dentin deposition as well as faster cement degradation as measured by µCT assessment. In conclusion, the presented theranostic agent matches the imaging and regenerative requirements for pulp capping applications.
1
1. INTRODUCTION The healthy state of dental pulp can be compromised after exposed to an extended caries or traumatic injury [1]. Different strategies for vital pulp treatment, such as direct and indirect pulp capping and partial pulpotomy, are performed to maintain the integrity and the vitality of the tooth. A capping material can serve to protect the exposed pulp and to promote dental pulp stem cells to differentiate into odontoblasts, which subsequently produce tertiary dentin (i.e. the “dentin bridge”) [2,3]. Based on the intensity of the external stimulus, tertiary dentin can be distinguished in reactionary dentin and reparative dentin [4]. The deposition of reactionary dentin occurs in the case of mild stimuli and is guided by post-natal odontoblasts that have survived to the initial damage. Reparative dentin is secreted in the case of severe external stimuli and is guided by newly formed odontoblast-like cells [5,6]. An ideal material for vital pulp therapy needs to be biocompatible, have optimal handling properties, show imaging contrast, and induce dentin deposition. Historically, calcium hydroxide has been widely used for this specific application especially because of its antimicrobial and reparative properties [7,8]. Therefore, calcium hydroxide is considered as gold standard. However, some limitations, such as lack of pulp sealing, high solubility and the formation of “tunnel defects”, reduce calcium hydroxide capability to fulfill optimal clinical requirements [9,10]. Among many others compositions that have been investigated over the last years, calcium phosphate cement (CPC) appears to be a valid candidate as it shows biocompatibility, biodegradability, injectable and self-setting properties [11-13]. Moreover, it has been proven that CPC can also induce dentin mineralization and inhibit caries [14,15]. The combination of CPCs with specific growth factors (e.g. transforming growth factor beta, TGF-β, bone morphogenetic protein 2, BMP-2) can further improve the biological properties of the final material resulting in enhancement of tissue formation [16-18]. Another important consideration in the development of a pulp capping biomaterial is the capacity for imaging, necessary to assess the quality of the filling proximal to the pulp [1]. Although X-ray based technologies are widely implemented, concerns about the use of ionizing radiations [19] have led to investigations of other imaging techniques, like magnetic 2
resonance imaging (MRI), as a suitable alternative in dental screening. MRI is not only radiation free, but also allows for the simultaneous anatomical and functional tridimensional imaging of both soft and hard tissues [20,21]. Traditionally, the low presence of protons in bone and teeth results in a very short T2 relaxation (i.e. 500 µs for cortical bone and 250 µs for enamel, respectively) hampering their visualization. However, the newly developed MRI sequences with high sensitivity to ultra-short T2* relaxation (i.e. ultrashort echo time, UTE, and zero echo time, ZTE), have opened new scenarios for MRI in dental imaging with the improved visibility of bone and dental tissues [22-26]. In this study, a defined CPC composition -previously tested favorably for bone application [27]- was used for direct pulp capping in an in vivo animal model (i.e. goat incisors). Specifically, we aimed to produce a theranostic biomaterial, which combined a dedicated dual contrast agent (DCA) and BMP-2. The DCA consisted of core-shell superparamagnetic iron oxide (SPIO)/colloidal gold nanoparticles respectively as MRI and CT contrast agent, while BMP-2 was used to trigger dentin regeneration. Imaging performances of the cement were monitored seven weeks’ post-surgery by µCT and MRI. Finally, the biological response, new dentin formation, and cement degradation were assessed. 2. MATERIALS AND METHODS 2.1. CPC composition Calcium phosphate cement (CPC) consisted of a weight/weight (wt/wt) mixture of 59.1% alpha-tricalcium phosphate (α-TCP; CAM Bioceramics BV, Leiden, the Netherlands), 1.5 % carboxymethylcellulose (CMC; CAM Bioceramics) and 39.4% cryo-grinded poly-(DL-Lacticco-Glycolic acid) particles (
S1742-7061(17)30517-2 http://dx.doi.org/10.1016/j.actbio.2017.08.018 ACTBIO 5029
To appear in:
Acta Biomaterialia
Received Date: Revised Date: Accepted Date:
22 May 2017 12 July 2017 12 August 2017
Please cite this article as: Mastrogiacomo, S., Güvener, N., Dou, W., Alghamdi, H.S., Camargo, W.A., Cremers, J.G.O., Borm, P.J.A., Heerschap, A., Oosterwijk, E., Jansen, J.A., Walboomers, X.F., A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties, Acta Biomaterialia (2017), doi: http:// dx.doi.org/10.1016/j.actbio.2017.08.018
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Original Manuscript: Acta Biomaterialia A theranostic dental pulp capping agent with improved MRI and CT contrast and biological properties Mastrogiacomo S.1, Güvener N.2,3, Dou W.4, Alghamdi H.S.5, Camargo W.A.1, Cremers J.G.O.2, Borm P.J.A.2, Heerschap A.4, Oosterwijk E.6, Jansen J.A.1, Walboomers X.F.1* 1
Department of Biomaterials, Radboud
University Medical
Center,
Nijmegen,
the
Netherlands. 2
Nano4Imaging GmbH, Pauwelsstrasse 17, Aachen, Germany.
3
Institute for Experimental Molecular Imaging, RWTH Aachen University, Aachen, Germany.
4
Department of Radiology and Nuclear Medicine, Radboud University Medical Center,
Nijmegen, the Netherlands. 5
College of Dentistry Research Center, King Saud University, Riyadh, Saudi Arabia.
6
Department of Urology, Radboud University Medical Center, Nijmegen, the Netherlands.
Key words: CPC (calcium phosphate cement), DCA (dual contrast agent), BMP-2 (bone morphogenetic protein-2), MRI (magnetic resonance imaging), direct pulp capping. * Corresponding author. Tel.: +31 (0)615827220 / +31(0)243692932 E-mail address: [email protected]
ABSTRACT Different materials have been used for vital dental pulp treatment. Preferably a pulp capping agent should show appropriate biological performance, excellent handling properties, and a good imaging contrast. These features can be delivered into a single material through the combination of therapeutic and diagnostic agents (i.e. theranostic). Calcium phosphate based composites (CPCs) are potentially ideal candidate for pulp treatment, although poor imaging contrast and poor dentino-inductive properties are limiting their clinical use. In this study, a theranostic dental pulp capping agent was developed. First, imaging properties of the CPC were improved by using a core-shell structured dual contrast agent (csDCA) consisting of superparamagnetic iron oxide (SPIO) and colloidal gold, as MRI and CT contrast agent respectively. Second, biological properties were implemented by using a dentinogenic
factor
(i.e.
bone
morphogenetic
protein
2,
BMP-2).
The
obtained
CPC/csDCA/BMP-2 composite was tested in vivo, as direct pulp capping agent, in a male Habsi goat incisor model. Our outcomes showed no relevant alteration of the handling and mechanical properties (e.g. setting time, injectability, and compressive strength) by the incorporation of csDCA particles. In vivo results proved MRI contrast enhancement up to 7 weeks. Incisors treated with BMP-2 showed improved tertiary dentin deposition as well as faster cement degradation as measured by µCT assessment. In conclusion, the presented theranostic agent matches the imaging and regenerative requirements for pulp capping applications.
1
1. INTRODUCTION The healthy state of dental pulp can be compromised after exposed to an extended caries or traumatic injury [1]. Different strategies for vital pulp treatment, such as direct and indirect pulp capping and partial pulpotomy, are performed to maintain the integrity and the vitality of the tooth. A capping material can serve to protect the exposed pulp and to promote dental pulp stem cells to differentiate into odontoblasts, which subsequently produce tertiary dentin (i.e. the “dentin bridge”) [2,3]. Based on the intensity of the external stimulus, tertiary dentin can be distinguished in reactionary dentin and reparative dentin [4]. The deposition of reactionary dentin occurs in the case of mild stimuli and is guided by post-natal odontoblasts that have survived to the initial damage. Reparative dentin is secreted in the case of severe external stimuli and is guided by newly formed odontoblast-like cells [5,6]. An ideal material for vital pulp therapy needs to be biocompatible, have optimal handling properties, show imaging contrast, and induce dentin deposition. Historically, calcium hydroxide has been widely used for this specific application especially because of its antimicrobial and reparative properties [7,8]. Therefore, calcium hydroxide is considered as gold standard. However, some limitations, such as lack of pulp sealing, high solubility and the formation of “tunnel defects”, reduce calcium hydroxide capability to fulfill optimal clinical requirements [9,10]. Among many others compositions that have been investigated over the last years, calcium phosphate cement (CPC) appears to be a valid candidate as it shows biocompatibility, biodegradability, injectable and self-setting properties [11-13]. Moreover, it has been proven that CPC can also induce dentin mineralization and inhibit caries [14,15]. The combination of CPCs with specific growth factors (e.g. transforming growth factor beta, TGF-β, bone morphogenetic protein 2, BMP-2) can further improve the biological properties of the final material resulting in enhancement of tissue formation [16-18]. Another important consideration in the development of a pulp capping biomaterial is the capacity for imaging, necessary to assess the quality of the filling proximal to the pulp [1]. Although X-ray based technologies are widely implemented, concerns about the use of ionizing radiations [19] have led to investigations of other imaging techniques, like magnetic 2
resonance imaging (MRI), as a suitable alternative in dental screening. MRI is not only radiation free, but also allows for the simultaneous anatomical and functional tridimensional imaging of both soft and hard tissues [20,21]. Traditionally, the low presence of protons in bone and teeth results in a very short T2 relaxation (i.e. 500 µs for cortical bone and 250 µs for enamel, respectively) hampering their visualization. However, the newly developed MRI sequences with high sensitivity to ultra-short T2* relaxation (i.e. ultrashort echo time, UTE, and zero echo time, ZTE), have opened new scenarios for MRI in dental imaging with the improved visibility of bone and dental tissues [22-26]. In this study, a defined CPC composition -previously tested favorably for bone application [27]- was used for direct pulp capping in an in vivo animal model (i.e. goat incisors). Specifically, we aimed to produce a theranostic biomaterial, which combined a dedicated dual contrast agent (DCA) and BMP-2. The DCA consisted of core-shell superparamagnetic iron oxide (SPIO)/colloidal gold nanoparticles respectively as MRI and CT contrast agent, while BMP-2 was used to trigger dentin regeneration. Imaging performances of the cement were monitored seven weeks’ post-surgery by µCT and MRI. Finally, the biological response, new dentin formation, and cement degradation were assessed. 2. MATERIALS AND METHODS 2.1. CPC composition Calcium phosphate cement (CPC) consisted of a weight/weight (wt/wt) mixture of 59.1% alpha-tricalcium phosphate (α-TCP; CAM Bioceramics BV, Leiden, the Netherlands), 1.5 % carboxymethylcellulose (CMC; CAM Bioceramics) and 39.4% cryo-grinded poly-(DL-Lacticco-Glycolic acid) particles (
