Implants made of poly(lactide-co-glycolide) (PLGA) are biodegradable and frequently provoke foreign body reactions (FBR) in the host tissue. In order to modulate the inflammatory response of the host tissue, PLGA implants can be loaded with anti-inflammatory drugs. The aim of this study was to analyze the impact of PLGA 80/20 rods loaded with the diclofenac sodium (DS) on local tissue reactions in the femur of rats. Special emphasis was put on bone regeneration and the presence of multinucleated giant cells (MGCs) associated with FBR. PLGA 80/20 alone and PLGA 80/20 combined with DS was extruded into rods. PLGA rods loaded with DS (PLGA+DS) were implanted into the femora of 18 rats. Eighteen control rats received unloaded PLGA rods. The follow-up period was of 3, 6 and 12 weeks. Each group comprised of six rats. Peri-implant tissue reactions were histologically and histomorphometrically evaluated. The implantation of PLGA and PLGA+DS8 rods induced the formation of a layer of newly formed bone islands parallel to the contour of the implants. PLGA+DS rods tended to reduce the presence of multi-nucleated giant cells (MGCs) at the implant surface. Although it is known that the systemic administration of DS is associated with compromised bone healing, the local release of DS via PLGA rods did not have negative effects on bone regeneration in the femora of rats throughout 12 weeks.

Conventional occlusal analysis methods are increasingly challenged by digital technologies. The purpose of this study was to compare the accuracy and reliability of currently available conventional and digital occlusal indicators. The number and distribution of occlusal contacts in habitual intercuspation (ICP) were recorded in 26 dentate adults using articulating silk (reference method), wax occlusogram, and the digital occlusal analysis system T-Scan Novus. Errors in the number and distribution of contact registration between the methods, as well as inter- and intra-observer agreement, were calculated per dental arch and tooth position. The distribution of contacts within the dental arch followed a method-independent pattern. Per dental arch, articulating silk recorded 15.3±4.7 contacts, wax occlusogram 14.2±4.6, and the T-Scan 9.4±5.9. Agreement between the methods was highest for incisors and canines and lowest for premolars and molars. ICC for intra- and inter-observer agreement were considerably lower for wax occlusogram (0.36/0.34) than for the T-Scan (0.66/0.58). Wax occlusogram recorded a higher number of occlusal contacts, whereas the T-Scan systematically registered fewer contacts but demonstrated greater intra- and inter-observer reliability. These differences suggest that conventional methods may provide a broader visualisation of contact distribution, while digital tools offer benefits in terms of reproducibility. Articulating silk and wax occlusogram, register a summation of contacts including premature contacts enabling a more comprehensive occlusal diagnosis. In contrast, the T-Scan may be preferred when the identification of force distribution is the primary focus.

Research in maxillary sinus floor augmentation (MSFA) focussed on the optimisation of microstructural parameters such as microporosity and particle size of bone substitute particles (BS). However, little is known about the impact of BS packing and the corresponding (void) interparticular space on bone regeneration. The aim of this study was to characterise the spatial distribution of BS and its association with BS integration 6 ± 1 months after MSFA. Histological thin-ground sections of 70 human sinus biopsies were histomorphometrically analysed: In serial zones of 100 µm proceeding from the sinus floor (SF) up to the apical end of the biopsy, we measured the distribution of BS particles within these zones in terms of volume (BSV/TV), number and size of BS particles, interparticle spacing (BS.Sp) and bone-to-BS contact. BS particles were not homogeneously distributed over the length of biopsies: The first 200 µm directly adjacent to the SF represented a zone poor in BS particles but with high osteogenic potential. Graft packing density increased from the SF towards the apical part of the AA. Integration of BS particles was inversely associated with the distance to the SF and the graft packing density. A high packing density through excessive compaction of BS particles should be avoided to optimise the macrostructural environment for bone regeneration.

The cyclic axial dynamisation of a stabilised fracture is intended to promote callus formation and bone healing. Most studies focused on biomechanical properties or the quantity of new bone formation. Far less is known about the quality of newly formed callus tissues, such as tissue distribution and arrangement within the callus. The aim of this current study was to investigate the effect of cyclic, axial dynamisation on the quantity and quality of callus in an established delayed fracture healing model. In 41 sheep transverse osteotomies with a gap size of 3 mm were stabilised with a unilateral external fixator. In 32 of these, fracture ends were axially stimulated with displacement amplitudes of 0.8 mm, 0.4 mm, 0.2 mm, or 0.0 mm, respectively, for six weeks. In the remaining 9 sheep of the control group, an additional external fixator was mounted to achieve almost total rigidity. Animal material originating from a past animal experiment was reanalysed in this study. Histological thin-ground sections were histomorphometrically analysed regarding the histological structure and composition of the defect region. A slight tendency towards an increase in size of total callus area, area of new bone (nB.Ar), and cartilage (Cg.Ar) was detected with increasing displacement amplitudes compared to the control group. At the anterior callus side nB.Ar and Cg.Ar were significantly larger than at the posterior side in all groups independent of treatment. Regarding the quality of callus, areas of very compact bone were predominant in the treatment groups whereas in the control group a slight shift to more porous bone was observed. No difference of callus compactness was observed between the anterior and the posterior side. The established method to assess the local compactness of callus areas is a useful tool to quantitatively determine the spatial distribution of new bone tissue within the callus. The application of this method in combination with biomechanical testing might reveal interesting relations between tissue distribution and bone strength that, with traditional histomorphometry, cannot be identified.

Lateral facial clefts are rare and often part of more complex syndromic neurocristopathies. According to Tessier’s classification, they correspond to facial cleft numbers 6, 7 and 8. Using micro-computer tomography (micro-CT), we analyzed their underlying bone defects (resolution 50 and 55 µm/voxel) in the context of the known syndrome-specific genetic background. Lateral facial clefts were diagnosed in three severely affected museum specimens representing mandibulofacial dysostosis type Treacher Collins syndrome (TCS), acrofacial dysostosis syndrome of Rodriguez (AFD-Rod) and tetra-amelia syndrome (TETAMS). The TCS specimen mainly showed an absence of the zygomatic bones and most of the lateral maxilla. The AFD-Rod specimen showed an extensive defect of the lateral maxilla, zygomatic bones, and mandible. The TETAMS specimen showed almost isolated agnathia. Possible relationships are discussed between the diverse facial bone defects due to apoptosis of neural crest-derived cells, known to be associated with ribosomopathies and spliceosomopathies, such as TCS and AFD-Rod, and the more targeted bone defects due to genetic variants known to cause TETAMS.