Histologic response to porous PMMA implant materials

Nathanson, Dan; Gettleman, Lawrence; Schnitman, Paul A.; Shklar, Gerald

doi:10.1002/jbm.820120103

Cited by 26 publications

(9 citation statements)

References 18 publications

(2 reference statements)

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“…First, although porous PMMA has been well studied, 24,27,[36][37][38][39] including porous PMMA fabricated using an aqueous phase consisting of a CMC hydrogel as a porogen, 25,40 the present study is one of the first systematic studies of fabrication methods to quantitatively examine the effect of both the ratio of aqueous phase to polymer phase but also the effect of the aqueous phase viscosity as done by varying the amount of CMC within the aqueous phase. Increasing the viscosity of the aqueous phase by using a 9 wt% CMC hydrogel, as opposed to a 7 wt% CMC gel as has been previously used, 41 resulted in a more consistent pore architecture with smaller, more consistently sized pore interconnections.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Soft Tissue Coverage over Porous Polymethylmethacrylate Space Maintainers Within Nonhealing Alveolar Bone Defects

Kretlow

Shi

Young

et al. 2010

Tissue Engineering Part C: Methods

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Current treatment of traumatic craniofacial injuries often involves early free tissue transfer, even if the recipient site is contaminated or lacks soft tissue coverage. There are no current tissue engineering strategies to definitively regenerate tissues in such an environment at an early time point. For a tissue engineering approach to be employed in the treatment of such injuries, a two-stage approach could potentially be used. The present study describes methods for fabrication, characterization, and processing of porous polymethylmethacrylate (PMMA) space maintainers for temporary retention of space in bony craniofacial defects. Carboxymethylcellulose hydrogels were used as a porogen. Implants with controlled porosity and pore interconnectivity were fabricated by varying the ratio of hydrogel:polymer and the amount of carboxymethylcellulose within the hydrogel. The in vivo tissue response to the implants was observed by implanting solid, low-porosity, and high-porosity implants (n = 6) within a nonhealing rabbit mandibular defect that included an oral mucosal defect to allow open communication between the oral cavity and the mandibular defect. Oral mucosal wound healing was observed after 12 weeks and was complete in 3/6 defects filled with solid PMMA implants and 5/6 defects filled with either a low- or high-porosity PMMA implant. The tissue response around and within the pores of the two formulations of porous implants tested in vivo was characterized, with the low-porosity implants surrounded by a minimal but well-formed fibrous capsule in contrast to the high-porosity implants, which were surrounded and invaded by almost exclusively inflammatory tissue. On the basis of these results, PMMA implants with limited porosity hold promise for temporary implantation and space maintenance within clean/contaminated bone defects.

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Section: Discussionmentioning

confidence: 99%

Evaluation of Soft Tissue Coverage over Porous Polymethylmethacrylate Space Maintainers Within Nonhealing Alveolar Bone Defects

Kretlow

Shi

Young

et al. 2010

Tissue Engineering Part C: Methods

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“…Materials currently available in the clinic, such as polymethylmethacrylate (PMMA), generally do not meet the needs of the space maintenance application, and commonly result in infection and wound dehiscence 9, 11–13. However, porous PMMA has been previously shown to enhance integration with the surrounding soft and hard tissue, resulting in less dehiscence than solid PMMA 13–16. Notwithstanding, PMMA has been used for arthroplasty fixation and cranioplasty for decades with many advantages such as moldability and rapid setting time 17, 18.…”

Section: Introductionmentioning

confidence: 99%

Characterization of porous polymethylmethacrylate space maintainers for craniofacial reconstruction

et al. 2013

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Porous polymethylmethacrylate (PMMA) has been used as an alloplastic bone substitute in the craniofacial complex, showing integration with the surrounding soft and hard tissue. This study investigated the physicochemical properties of curing and cured mixtures of a PMMA-based bone cement and a carboxymethylcellulose (CMC) gel porogen. Four formulations yielding porous PMMA of varied porosity were examined; specifically, two groups containing 30% (w/w) CMC gel in the mixture using a 7% (w/v) or 9% (w/v) stock CMC gel (30-7 and 30-9, respectively) and two groups containing 40% (w/w) CMC gel (40-7 and 40-9). An additional group comprising solid PMMA without CMC was investigated. The incorporation of the CMC gel into the PMMA bone cement during polymerization decreased the setting time from 608 ± 12 s for the solid PMMA to 427 ± 10 s for the 40-9 group, and decreased the maximum temperature from 81 ± 4°C for the solid PMMA to 38 ± 2°C for the 40-9 group. The porous PMMA groups exhibited reduced compressive strength and bending modulus and strength relative to the solid PMMA. All the porous PMMA formulations released more unconverted methylmethacrylate (MMA) monomer and N,N-dimethyl-p-toluidine (DMT) from cured specimens and less MMA and DMT from curing specimens than the solid PMMA. The data suggest that the physicochemical properties of the porous PMMA formulations are appropriate for their application in craniofacial space maintenance.

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“…15,22 Similar to this study, where the solid and porous groups performed similarly histologically, a 14 week study by Nathanson et al and a 12 week study by Kretlow et al showed no difference in histological assessment of solid or porous implants at the end time point. 13,23 Contrary to these studies, van Mullem et al observed porous implants with 50 wt% of CMC gel as the porogen were surrounded by well-vascularized fibrous tissue, while solid implants had a thick fibrous capsule in a long term study of 8 and 24 months, indicating the possibility for further remodeling of the surrounding tissue in the porous implant group, which could differentiate the histological scores. 24 …”

Section: Discussionmentioning

confidence: 95%

In situ formation of porous space maintainers in a composite tissue defect

Spicer

Kretlow

Henslee

et al. 2012

J Biomedical Materials Res

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Reconstruction of composite defects involving bone and soft tissue presents a significant clinical challenge. In the craniofacial complex, reconstruction of the soft and hard tissues is critical for both functional and aesthetic outcomes. Constructs for space maintenance provide a template for soft tissue regeneration, priming the wound bed for a definitive repair of the bone tissue with greater success. However, materials used clinically for space maintenance are subject to poor soft tissue integration, which can result in wound dehiscence. Porous materials in space maintenance applications have been previously shown to support soft tissue integration and to allow for drug release from the implant to further prepare the wound bed for definitive repair. This study evaluated solid and low porosity (16.9 ± 4.1%) polymethylmethacrylate space maintainers fabricated intraoperatively and implanted in a composite rabbit mandibular defect model for 12 weeks. The data analyses showed no difference in the solid and porous groups both histologically, evaluating the inflammatory response at the interface and within the pores of the implants, and grossly, observing the healing of soft tissue defect over the implant. These results demonstrate the potential of porous polymethylmethacrylate implants formed in situ for space maintenance in the craniofacial complex, which may have implications in the potential delivery of therapeutic drugs to prime the wound site for a definitive bone repair.

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Histologic response to porous PMMA implant materials

Cited by 26 publications

References 18 publications

Evaluation of Soft Tissue Coverage over Porous Polymethylmethacrylate Space Maintainers Within Nonhealing Alveolar Bone Defects

Evaluation of Soft Tissue Coverage over Porous Polymethylmethacrylate Space Maintainers Within Nonhealing Alveolar Bone Defects

Characterization of porous polymethylmethacrylate space maintainers for craniofacial reconstruction

In situ formation of porous space maintainers in a composite tissue defect

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