Paweł Kubasiewicz-Ross

A silver carp skin derived collagen in bone defect treatment-A histological study in a rat model.

In recent years, there has been increasing interest in elaboration of novel therapeutic strategies, such as the use of the marine collagen products. Biochemical properties of marine collagen are different from those of mammalian collagen; e.g., its extremely high solubility in diluted acid. Extracts produced using low temperature techniques contain a number of small proteins and collagen with preserved triple helix structure. The aim of the study was to evaluate the influence of a new marine product Collgel® obtained with a unique method from a silver carp (Hypophthalmichthys molitrix) on bone defect healing in a rat study. For this purpose bone defects with diameters of 5mm were created in 15 animals and subsequently filled with Collgel combined with another commercially available material. Samples were processed for histological evaluation and a Micro-CT study was performed. Histological analysis showed new bone formation in all groups after 8 weeks. The bone formation was significantly increased in treated bone lesions compared to untreated bone tissue. However no significant difference was noted between the healing of the defects filled with xenogenic bovine derived bone substitute alone and xenogenic, bovine derived bone substitute combined with a marine delivered collagen. Finding from the histological examination was confirmed in a Micro-CT study. The study has shown that the new marine product can be used instead of conventional porcine or bovine collagen membranes in guided bone regeneration.

New nano-hydroxyapatite in bone defect regeneration: A histological study in rats

Many types of bone substitute materials are available on the market. Researchers are refining new bone substitutes to make them comparable to autologous grafting materials in treatment of bone defects. The purpose of the study was to evaluate the osseoconductive potential and bone defect regeneration in rat calvaria bone defects treated with new synthetic nano-hydroxyapatite. The study was performed on 30 rats divided into 5 equal groups. New preproduction of experimental nano-hydroxyapatite material by NanoSynHap (Poznań, Poland) was tested and compared with commercially available materials. Five mm critical size defects were created and filled with the following bone grafting materials: 1) Geistlich Bio-Oss®; 2) nano-hydroxyapatite+β-TCP; 3) nano-hydroxyapatite; 4) nano-hydroxyapatite+collagen membrane. The last group served as controls without any augmentation. Bone samples from calvaria were harvested for histological and micro-ct evaluation after 8 weeks. New bone formation was observed in all groups. Histomorphometric analysis revealed an amount of regenerated bone between 34.2 and 44.4% in treated bone defects, whereas only 13.0% regenerated bone was found in controls. Interestingly, in group 3, no significant particles of the nano-HA material were found. In contrast, residual bone substitute material could be detected in all other test groups. Micro-CT study confirmed the results of the histological examinations. The new nano-hydroxyapatite provides comparable results to other grafts in the field of bone regeneration.

Comparison of surface modified zirconia implants with commercially available zirconium and titanium implants: a histological study in pigs.

Introduction:New biomaterials and their various surface modifications should undergo in vitro and in vivo evaluation before clinical trials. The objective of our in vivo study was to evaluate the biocompatibility of newly created zirconium implant surfaces after implantation in the lower jaw of pigs and compare the osseointegration of these dental implants with commercially available zirconium and titanium implants. Materials and Methods:After a healing period of 12 weeks, a histological analysis of the soft and hard tissues and a histomorphometric analysis of the bone-implant contact (BIC) were performed. Results:The implant surfaces showed an intimate connection to the adjacent bone for all tested implants. The 3 newly created zirconium implant surfaces achieved a BIC of 45% on average in comparison with a BIC of 56% from the reference zirconium implants and 35% from titanium implants. Furthermore, the new zirconium implants had a better attachment to gingival and bone tissues in the range of implant necks as compared with the reference implants. Conclusion:The results suggest that the new implants comparably osseointegrate within the healing period, and they have a good in vivo biocompatibility.

Fractal dimension analysis a supplementary mathematical method for bone defect regeneration measurement

AIM OR PURPOSE The geometry of a bone defect is very complex. Its shape is too complicated to measure or compare with other bone defects using only traditional measuring methods Traditional measuring techniques based on the histomorphometric analysis of a bone specimen require supplementary measuring. For the fractal dimension analysis (FDA) mathematic formulas are used to describe complicated and chaotic shapes. The FDA offers a possibility of a comparison between complicated and complex shapes such as a histological image of a bone defect. The aim of this study was to evaluate the FDA of bone defects as a supplementary method for a defect regeneration assessment. MATERIALS AND METHODS For the purpose of this study, microscopic photographs of bone specimens stained with hematoxylin and eosin obtained during a block biopsy were used. The bone blocks used in this study were obtained during a rat animal model study. Specimens were collected from 36 Wistar rats where a cranial defect was created and augmented with five different novel biomaterials and compared to the unfilled defect in the control group. New bone formation in every specimen was histomorphometrically measured by two independent operators and compared to FDA measurements. RESULTS Both traditional and FDA techniques have shown statistically significant differences between bone formation in test groups compared to the control one; on the other hand, no statistically significant difference was found between other groups. The Pearsons r-test was conducted to measure the linear dependence (correlation) between standard measurements and the FDA, and a positive linear correlation was found -r=0.94. CONCLUSIONS The FDA can be used as a supplementary method for bone regeneration measurements.

Osseointegration of zirconia implants with 3 varyingsurface textures and a titanium implant:A histological and micro-CT study

BACKGROUND Zirconium - a bioinert metal - in comparison with titanium implants, offers a variety of potential advantages for use in the esthetic area of dentistry due to its tooth-like color. Zirconium dental implants are considered to be an alternative method of treatment to conventional titanium dental implants for patients with a thin gingival biotype. OBJECTIVES This study was designed to study the bone tissue response to new zirconia implants with modified surfaces in comparison with commercially available titanium dental implants and commercially available zirconia implants. MATERIAL AND METHODS The study was carried out on a group of 12 16-month-old minipigs. New zirconia implants with 3 different surfaces were used: M1 - blasted surface, M2 - etched surface and M3 - blasted and etched surface (Maxon Motor GmbH, Sexau, Germany) and compared to conventional titanium implants with an sandblasted and acid etched (SLA) surface (Straumann GmbH, Freiburg, Germany) and commercially available zirconia implants (Ziterion GmbH, Uffenheim, Germany). Histological and micro-computed tomopgraphy (micro-CT) evaluation was performed. RESULTS In the micro-CT assessment, the average bone-implant contact (BIC) of the zirconia experimental implants was 41.44%. In particular, the BIC% for M1 was 39.72%, for M2 it was 43.97%, and for M3 - 40.63%; in the control group it was 49.63% and 27.77% for ceramic and titanium control implants, respectively. The intra-group analysis showed no statistically important differences between the BIC values for implants in any group. However, the analysis of BIC for different regions of the same implant showed statistically significant differences in all of the groups between the results of the threaded region and the neck and the apex. CONCLUSIONS The results of our study suggest that zirconia implants with modified surfaces display features of osseointegration similar to those of titanium implants. These results are promising in using zirconia implants for dental applications in the future.

Application of fractal dimension analysisand photodynamic diagnosis in the case of differentiationbetween lichen planus and leukoplakia: A preliminary study

BACKGROUND Photodynamic therapy (PDT) is a noninvasive method for the treatment of premalignant lesions, such as leukoplakia and lichen planus (LP). These lesions are very irregular. In the case of such irregular lesions, fractal dimension analysis (FDA) is very helpful. Photodynamic diagnosis (PDD) enables the visualization of irregular lesion shapes more precisely than a classical white-light examination. OBJECTIVES In our study, we tried to distinguish oral leukoplakia and LP, using FDA in a classical examination with white light and PDD. Lesions treated using PDT were histopathologically verified. MATERIAL AND METHODS We enrolled 35 patients in our study. Fractalyse software v. 2.4 (University of Franche-Comté, Besançon, France) was used to count fractal dimensions (FDs). Photodynamic therapy and PDD were mediated with 20% delta-aminolevulinic acid (5-ALA). RESULTS Fractal dimensions of leukoplakia foci of the tongue in a white-light examination were significantly lower than in PDD. In the case of LP, a significant difference of FDs was observed between lesions in the cheek and in the alveolar ridge region. Differences in FDs were observed between leukoplakia foci of the alveolar ridge, tongue and palate. A complete response of leukoplakia foci to PDT was observed in 10 out of 34 lesions, partial remission occurred in 20 lesions and a total lack of response was noted in 4 lesions. Generally, LP was completely treated in 7 out of 14 cases, a partial response was observed in 5 lesions and a failure of PDT treatment was noted in 2 cases. CONCLUSIONS Fractal dimension analysis may be a useful method in the comparison of complicated shapes of such lesions as LP or leukoplakia, but our study did not confirm that this method may be used to distinguish LP and leukoplakia without a histopathological examination. Photodynamic therapy is an effective treatment method in the case of LP and leukoplakia of the oral cavity.