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Abstract: Bone replacement using synthetic and degradable materials is desirable in various clinical conditions. Most applied commercial materials are based on hydroxyapatite, which is not chemically degradable under physiological conditions. Here we report the effect of a long-term intramuscular implantation regime on the dissolution of various low temperature calcium and magnesium phosphate ceramics in vivo. The specimens were analysed by consecutive radiographs, micro-computed tomography scans, compressive strength testing, scanning electron microscopy and X-ray diffractometry. After 15months in vivo, the investigated materials brushite (CaHPO4·2H2O), newberyite (MgHPO4·3H2O), struvite (MgNH4PO4·6H2O) and hydroxyapatite (Ca9(PO4)5HPO4OH) showed significant differences regarding changes of their characteristics. Struvite presented the highest loss of mechanical performance (95%), followed by newberyite (67%) and brushite (41%). This was accompanied by both a distinct extent of cement dissolution as well as changes of the phase composition of the retrieved cement implants. While the secondary phosphate phases (brushite, newberyite, struvite) completely dissolved, re-precipitates of whitlockite and octacalcium phosphate were formed in either particulate or whisker-like morphology. Furthermore, for the first time the possibility of a macropore-free volume degradation mechanism of bioceramics was demonstrated. [Copyright &y& Elsevier]

Abstract: Although there is principal agreement that increased facial asymmetry is associated with decreased facial attractiveness, there are no studies analysing face perception in patients with a unilateral cleft lip and palate (CLP) (uCLP) compared to orthognathic Class III patients. To this end, three-dimensional (3D) data on the faces of 30 adults with a complete uCLP, 20 orthognathic patients with a severe skeletal Class III, and 20 adults with a skeletal Class I as a control group were generated. The 3D asymmetry of the facial soft-tissue was analysed. These data were compared with subjective ratings for attractiveness carried out by 100 laypersons. Compared to the controls, uCLP patients and orthognathic patients had a significantly higher facial asymmetry. No difference was found between uCLP patients and orthognathic patients. The attractiveness ratings showed that uCLP patients and orthognathic patients were rated less attractive compared to the controls. However, although there were no differences in the facial asymmetry between uCLP patients and orthognathic patients, the uCLP patients were rated significantly less attractive. This leads to the conclusion that not only the extent of asymmetry has an influence on attractiveness but also the location of asymmetry. For clinical use, these findings underline the importance of accurate as possible surgical reconstruction of the nasal morphology in uCLP patients. [Copyright &y& Elsevier]

Summary: Background: The aim of this study was to investigate the processing and the possible use of 3D powder printed calcium phosphate implants for the reconstruction of cranial and maxillofacial defects. Materials: The fabrication of the implants was carried out with a commercial 3D powder printing system. Diluted phosphoric acid was printed onto tricalcium phosphate powder, leading to the formation of dicalcium phosphate dihydrate (Brushite). Hydrothermal conversion of the brushite matrices led to the formation of dicalcium phosphate anhydrous (Monetite). Method: Bony defects were generated using a human cadaver skull. The implants were computer-aided designed (CAD) using a mirror imaging procedure following computed tomography of the skull. Specific implants were manufactured by the 3D powder printing rapid prototyping technique. Result: The processing chain from data acquisition to printing of the implants proved to be practical and uncomplicated. The individual implants showed a high degree of accuracy of fit. Mechanical and physical investigations revealed suitable characteristics. Conclusion: 3D powder printing of calcium phosphate cement material provides a promising new method for the manufacturing of biodegradable synthetic patient-specific craniofacial implants. [Copyright &y& Elsevier]

Abstract: Brushite (CaHPO4·2H2O)-forming calcium phosphate cements are of great interest as bone replacement materials because they are resorbable in physiological conditions. However, their short setting times and low mechanical strengths limit broad clinical application. In this study, we showed that a significant improvement of these properties of brushite cement could be achieved by the use of magnesium-substituted β-tricalcium phosphate with the general formula Mg x Ca(3– x )(PO4)2 with 0< x <3 as cement reactants. The incorporation of magnesium ions increased the setting times of cements from 2min for a magnesium-free matrix to 8–11min for Mg2.25Ca0.75(PO4)2 as reactant. At the same time, the compressive strength of set cements was doubled from 19MPa to more than 40MPa after 24h wet storage. Magnesium ions were not only retarding the setting reaction to brushite but were also forming newberyite (MgHPO4·3H2O) as a second setting product. The biocompatibility of the material was investigated in vitro using the osteoblast-like cell line MC3T3-E1. A considerable increase of cell proliferation and expression of alkaline phosphatase, indicating an osteoblastic differentiation, could be noticed. Scanning electron microscopy analysis revealed an obvious cell growth on the surface of the scaffolds. Analysis of the culture medium showed minor alterations of pH value within the physiological range. The concentrations of free calcium, magnesium and phosphate ions were altered markedly due to the chemical solubility of the scaffolds. We conclude that the calcium magnesium phosphate (newberyite) cements have a promising potential for their use as bone replacement material since they provide a suitable biocompatibility, an extended workability and improved mechanical performance compared with brushite cements. [Copyright &y& Elsevier]

Summary: Background: Midfacial distraction following Le Fort III osteotomy has become an established procedure for midfacial advancement of syndromic craniosynostosis patients. A frequent difficulty is the precise three dimensional (3D) alignment of the distracted midface and the proper fixation of the distraction device in the midfacial area. In this study we present an individual modification method for commercial distraction devices comprising the establishment of prefabricated fixation plates and parallel connecting pins. Material: Individual prefabricated fixation plates for the zygomatic buttress were combined with two commercial distraction devices. Method: The fixation plates were made by a casting technique using individual cranial models as templates. The latter were fabricated by the rapid prototyping technique of 3D powder printing. For precise realization of the distraction vector, two commercial devices were combined and attached rigidly to the fixation plates by two parallel pins. Result: In the clinical routine, the 3D powder printing technique enables the simple fabrication of precise individual cranial models, which are required for manufacturing individual fixation plates. The combination of two commercial distraction devices facilitates the appropriate transfer of complex distraction vectors into the midfacial area. Conclusion: The technique presented should be useful for a precise multi-directional midfacial distraction following Le Fort III osteotomy. [Copyright &y& Elsevier]

Objectives: The lack of oral mucosa in oral and maxillofacial surgery for intraoral grafting after trauma or tumor resection can be balanced by tissue-engineered oral mucosa. The aim of this study was to generate a tissue-engineered oral mucosa equivalent (OME). Study Design: First, primary oral fibroblasts were cultured for 7 days on different materials: Tissufoil E (TFE), dermal regeneration template (DRT), and Vicryl. Then, cocultures were established by seeding of primary oral keratinocytes and culturing for another 7-14 days. Immunohistochemical staining for CD90, cytokeratin 14 and collagen IV as well as gene expression analysis using reverse-transcription quantitative polymerase chain reaction were used to get information about cell architecture and basal membrane formation. Results: Vicryl showed good mechanical stability but mixed cell growth. TFE provided the best cell growth with good cell architecture and basal membrane formation but showed degradation. The best results for the above-mentioned criteria were seen with DRT. Conclusions: It was possible to create OMEs on all 3 scaffolds. The arrangement of the cells strongly depends on the texture of the material. [ABSTRACT FROM AUTHOR]