Three-Dimensional Bone Block Planning for Mandibular Sagittal Bone Defect Reconstruction.

Bone defects seen in severe sagittal discrepancies between the maxilla and mandible do not solely qualify for orthodontic treatment. An interdisciplinary approach with the aid of a surgical, orthodontic, and periodontal team should be implemented in the treatment of such cases. Despite the use of standard treatment methods, the therapy is always planned and carried out individually for each patient. The surgical treatment of bone defects in the area of the jawbones is associated with a number of potential complications. Regenerative medicine, which has already been practiced in reconstructive surgery, is now gradually receiving more attention in the treatment of orthognathic defects. We developed a method for the reconstruction of the alveolar bone in the sagittal dimension using 3D allogenic graft blocks, as a preparing feature in the orthodontic treatment of borderline cases or as a treatment option for complications arising during general orthodontic treatment.

Changes in caveolin-1, caveolin-3 and vascular endothelial growth factor expression and protein content after botulinum toxin A injection in the right masseter muscle of dystrophin deficient (mdx-) mice.

Progressive muscle wasting, frequently associated with inflammation, muscle fibre degeneration and fibrosis, is a characteristic of DMD (Duchenne muscular dystrophy). Its most common used animal model, the mdx mouse, however can overcome muscle degeneration by regeneration processes and is for this reason not suitable to answer all scientific questions. The aim of this study was to evaluate the ability of botulinum toxin A (BTX-A) in breaking down muscle regeneration in mdx mice. For this purpose, the right masseter muscle of 100 days old mdx and healthy mice was paralyzed by a single specific intramuscular injection of BTX-A. After 21 days, right and left masseter and temporal muscles as well as tongue muscle were carefully dissected, and gene and protein expression of caveolin-1, caveolin-3 and vascular endothelial growth factor (VEGF) were determined using quantitative RT-PCR and Western blot technique. Statistics were performed using Student's t-test and Mann Whitney U-test (significance level: P ≤ 0.05). After BTX-A injection, in both mice strains and for all three studied genes, no significant differences in mRNA amount could be detected between treated and untreated masseter muscles. A significant increase in caveolin-1, caveolin-3 and VEGF mRNA expression could only be found in the right temporal muscle of control mice compared to the left side. All three investigated proteins were more frequent to be found in dystrophic masseter muscle samples compared to the corresponding control samples, whereas significant decreased caveolin-3 protein levels could only be detected in the treated masseter versus untreated masseter muscle of controls. In contrast to previous conclusions, with this study it was not possible to prove a BTX-A-induced dystrophic phenotype in control animals, in which only the known decreases of caveolin-3 protein expression could be verified due to denervation. At the same time, however, gene and protein expression in dystrophic mice was not changed after BTX-A injection.

Harmonisation of Dental Education in Europe - a survey about 15 years after visitation of dental schools participating in the DentEd project.

INTRODUCTION: The DentEd Thematic Networks (TNP) were funded from the EU to converge and harmonise the dental curricula. Forty-four dental schools participated in this visitation process between 1998 and 2002. The aim of the survey was to evaluate the implementation of the Dented outcomes in the curricula and if the concept of core competences are integrated in the curriculum. MATERIAL AND METHOD: In October 2012, questionnaires were sent out to all dental schools participated in the visitation process of Dented and Dented evolves. The main question blocs were as follows: structure of the curriculum and facilities, education of students, content and quality of education, assessment, research, European involvement and value of visit for the school. RESULTS: Twenty-five dental schools (57%) answered to the questionnaire. The responder represented 20 European countries of 22, whose schools were involved (91%). The self-assessment report was stimulating the continuation of curriculum improvement. Most of them acknowledge that major competences are essential outcome for the graduated dentist. Twelve schools (58%) rated the value of the DentEd visit with strong positive influence. DISCUSSION: The visits showed strengths, weaknesses and threats. Three-quarter of all schools implemented the European Credit Transfer System (ECTS). But most of them did not realize the unit of ECTS with modules among the Bologna process. CONCLUSION: The self-assessment report was a core issue for the continuation of curriculum improvement. The challenge for the ongoing curriculum improvement is the implementation of the module system among the Bologna recommendations.

Differential expression of genes involved in the calcium homeostasis in masticatory muscles of MDX mice.

Duchenne Muscular Dystrophy (DMD) and its murine model, mdx, are characterized by Ca(2+) induced muscle damage and muscle weakness followed by distorted dentofacial morphology. In both, DMD patients and in mdx mice, could be proven so far that only the extraocular muscles (EOM) are not affected by muscular dystrophy. The EOMs are protected against calcium overload by enhanced expression of genes involved in the Ca(2+) homeostasis. We could recently demonstrate that masticatory muscles of mdx mice are differentially affected by muscle dystrophy. The dystrophic masseter and temporalis shows muscle histology comparable to all other skeletal muscles in this animal model, whereas dystrophic tongue muscles seem to develop a milder phenotype. Due to this fact it is to hypothesize that an altered Ca(2+) homeostasis seems to underlie the mdx masticatory muscle pathology. Aim of this study was to examine the mRNA and protein levels of the sarcoplasmic reticulum Ca(2+) ATPases SERCA1 and SERCA2, the plasma membrane Ca(2+) ATPases Atp2b1 and Atp2b4, the sodium/calcium exchanger NCX1, the ryanodine receptor 1, parvalbumin, sarcolipin, phospholamban and the L-type Ca(2+) channel alpha-1 subunit (Cacna1s) in Musculus masseter, temporalis, and tongue of 100 day old control and mdx mice. In mdx masseter muscle significant increased mRNA levels of NCX1 and Cacna1s were found compared to control mice. In contrast, the mRNA amount of RYR1 was significant reduced in mdx temporalis muscle, whereas ATP2b4 was significant increased. In mdx tongue a down-regulation of the ATP2b1, sarcolipin and parvalbumin mRNA expression was found, whereas the phospholamban mRNA level was significantly increased compared to controls. These data were verified by western blot analyses. Our findings revealed that mdx masticatory muscles showed an unequally altered expression of genes involved in the Ca(2+) homeostasis that can support the differences in masticatory muscles response to dystrophin deficiency.

Student evaluation of problem-based learning in a dental orthodontic curriculum--a pilot study.

OBJECTIVE: The present questionnaire survey investigated student reception of problem-based learning (PBL) in the orthodontic curriculum with regard to acceptance, sense of purpose and motivation, knowledge and understanding, as well as tutorial support. METHODS: Over a period of two terms, we compared two different didactic methods (PBL and short presentations) by randomizing the participants of a course on orthodontic diagnostics into two different groups, who inversed methods after the first term. RESULTS: The two student groups did not show any significant differences with regard to assessments or examination performance. Therefore, acceptance of the PBL concept seems to be mainly associated with the motivation of individuals to use this method. The higher the motivation, the more positive is the attitude towards the PBL concept. Students seem to work more constructively and efficiently with PBL if they can judge the concept meaningful for themselves. CONCLUSION: In consideration of the relevant literature and the present results, PBL can be principally integrated into the dental curriculum as a method of learning. However, student motivation is vital to learning success.

Histological changes and changes in the myosin mRNA content of the porcine masticatory muscles after masseter treatment with botulinum toxin A.

OBJECTIVES: Botulinum toxin A (Botox) is increasingly used for treatment of muscle hyperfunction. For a better understanding of the possible morphologic and chewing changes in patients induced by a therapy with Botox, muscle fiber and myosin heavy chain (MyHC) mRNA alterations were examined in this animal study. MATERIALS AND METHODS: The investigation was carried out on 14-week-old pigs (seven treated animals, eight controls; calculated animal size with a power of 0.5). To initialise the total immobilisation of the right masseter, the Botox injection was distributed into ten areas. After a 56-day period, muscle tissue was taken from the left and right side of the masseter (three regions), temporal (two regions), medial pterygoid and geniohyoid muscles using a standardized method. The muscle fiber cross sections were examined immunohistochemically. Fiber staining was accomplished with antibodies to specific MyHC isoforms. The MyHC mRNA changes were analysed using real-time RT-PCR. RESULTS: Muscles adapt to such stress by changing fiber types and MyHC mRNA content. Paralysed masseters display atrophic changes while other masticatory muscles show hypertrophic changes. The results indicated that the typical distributions of type IIa und IIb fiber types in masticatory muscles were increased in the masseter muscles due to Botox application. On the other hand, the masseters without Botox in the treated group showed a significant increase of type I MyHC. CONCLUSIONS: Application of Botox may lead to uncontrolled structural changes in affected and unaffected muscles. CLINICAL RELEVANCE: Treatment of muscle hypertrophy with Botox may cause muscle imbalance.

Comparison of reference points in different methods of temporomandibular joint imaging.

PURPOSE: Conventional radiography is a well-established method for imaging of the temporomandibular joint (TMJ) structures. However, the dental computer tomography becomes more important for the visualization of teeth in the jaw-bone. The applicability of dental computer tomography for the visualization of the TMJ it not yet been proven. The aim of the study was to identify TMJ structures using reference points with the magnetic resonance imaging (MRI) and the computed tomography (CT). METHODS: In order to compare the visualization and measurement of the TMJ a total of eight human cadaver heads was examined with CT and MRI and analysed using reference points. RESULTS: In both imaging techniques the selected reference points and distances are well definable and allow objective evaluation of anatomical structures. The CT images display a clearly better contrast to noise ratio than the MR images. The distance measurement of different width and length showed significant correlation of both images techniques. CONCLUSIONS: In TMJ diagnostics, maximum information could be obtained using both imaging techniques together due to synergistic effects.

Changes in insulin like growth factors, myostatin and vascular endothelial growth factor in rat musculus latissimus dorsi by poly-3-hydroxybutyrate implants.

The present study aimed at researching the synergistic effect between an ectopic bone substitute and surrounding muscle tissue. To describe this effect, changes of insulin like growth factors (IGF1, IGF2), myostatin (GDF8) and vascular endothelial growth factor (VEGF) mRNA content of 12 Wistar-King rats musculus latissimus dorsi with implanted poly-3-hydroxybutyrate (PHB) scaffold were examined after 6 and 12 weeks. At each time interval six rats were killed and implants and surrounding tissues prepared for genetic evaluation. Eight rats without any implants served as controls. RNA was extracted from homogenized muscle tissue and reverse transcribed. Changes in mRNA content were measured by Real-Time PCR using specific primers for IGF1, IGF2, GDF8 and VEGF. Comparing the level of VEGF mRNA in muscle after 6 and 12 weeks to the controls, we could assess a significant increase of VEGF gene expression (p<0.05) whereas the level of mRNA expression was higher after 6 than after 12 weeks of treatment. Expression of IGF1 gene was also significantly increased as compared to the controls over the observed period of time (p<0.05). In the case of the IGF2 gene, the expression was significantly elevated after 6 weeks (p<0.05), but not significantly increased after 12 weeks (p>0.05). We observed a significantly decreased GDF8 gene expression (p<0.05) both after retrieval of implants after 6 as well as after 12 weeks. Moreover, mRNA level of GDF8 after 6 and 12 weeks were comparable the same. Our results show that PHB implants in rat musculus latissimus dorsi interact with the surrounding muscle tissue. This interaction works itself on growth potential of the muscle.

Skeletal muscle relaxants inhibit rat tracheal smooth muscle tone in vitro.

Neuromuscular blocking drugs (NMBD) can inhibit not only nicotinic but also muscarinic (M) receptors and thereby affect not only skeletal but also smooth muscle (SM) tone. A selective postjunctional muscarinic inhibition would relax, while prejunctional inhibition of muscarinic M2 receptor might hasten SM contraction thereby increasing the risk of bronchospasm. In rat tracheal rings in vitro we evaluated the effects of cumulative concentrations of some NMBD and M receptor blocking agents for their effects on tracheal smooth muscle (TSM) tone pre-contracted with carbachol (CARB; 5 x 10(-7)M or 10(-6)M), pilocarpine (PILO; 5 x 10(-6)M), or by electrical field stimulation. The NMBDs produced relaxation in the preparations precontracted with CARB or PILO. The order of potency after CARB (10(-6)M) was (EC(50)): 4-DAMP (9.8) >atropine (9.2) >methoctramine (6.4) >pancuronium (6.0) >mivacurium (5.8) >cisatracurium (5.6) >gallamine (5.2) >rocuronium (4.8) >succinylcholine (2.9); NMBDs also partially prevented contraction elicited by the electrical field stimulation. We demonstrated that the clinically used NMBD that were examined produced rat TSM relaxation, probably by predominantly blocking postjunctional muscarinic receptors.

Glutamine and alanyl-glutamine dipeptide reduce mesenteric plasma extravasation, leukocyte adhesion and tumor necrosis factor-α (TNF-α) release during experimental endotoxemia.

Glutamine (GLN) appears to be an essential nutrient during organism development and critical illness. The aim of our study was to evaluate the effects of GLN and its generic preparation alanyl-glutamine-dipeptide (DIP) on the microcirculation in endotoxemia in rats and its effects on tonus or aortal rings in vitro. Male Lewis rats (n=40) were separated in 4 groups. Group 1 (CON) served as healthy control group while the other groups received an endotoxin bolus i.v. (5 mg/kg lipopolysaccharide, LPS i.v.). In group 3 (LPS+GLN) 0.75 g/kg-1 GLN i.v. before LPS challenge was administered. In group 4 (LPS+DIP) DIP containing 0.75 g/kg GLN was given. Leukocyte-endothelial interactions and mesenteric plasma extravasation were determined at 0, 1 and 2 hours during the experiment by intravital fluorescence microscopy (IVM). Cytokine release (TNF-alpha, IL-1 beta, IL-6, IL-10) was measured by ELISA. GLN treatment reduced leukocyte adherence (-49.7% vs. LPS group, p<0.05) and plasma extravasation (-12.3% vs. LPS group, p<0.05) significantly during endotoxemia compared to untreated LPS animals. In group 4 (DIP+LPS), a decrease of leukocyte adherence (-56.0%) and mesenteric plasma extravasation (-18.8% vs. LPS group, p<0.05) was also found. TNF-alpha levels were reduced in both GLN and DIP (p<0.05). In vitro experiments demonstrated that glutamine agents could attenuate the response to contracting agents in presence of the vascular endothelium, implying nitric oxide pathway. In vivo, GLN as well as DIP pre-treatment diminish the detrimental impact of endotoxemia on the mesenteric microcirculation and the TNF-alpha release, the effects whose clinical importance should be further examined.

Efficacy of healing process of bone defects after apicectomy: results after 6 and 12 months.

The aim of this study was to assess the efficacy of selected surgical treatment techniques of bone defects after apectomy. A total of 106 postresection bone defects, located in maxilla and mandible were included in the study: the defects were treated with resorbable collagen membrane (BG I- 26 defects), xenogenic bovine material (BOC II- 30 defects) and xenogenic bovine material with platelet rich plasma (BOC/PRP III- 20 defects). In the control group the defects were left to heal spontaneously. Clinical and radiological assessment was performed at 6 and 12 months after the procedures. The analysis among groups revealed higher efficiency of the method of treatment that uses guide bone regeneration in comparison to the group in both post-operative control periods. After 6 months, the differences were statistically significant for each group using the regeneration methods, but after 12 months only for the BOC/PRP group. Treatment using selected guided bone regeneration techniques proved superior to the control group in both observation periods, but after 6 as well 12 months the best results in the BOC/PRP group were observed.

Influence of the implant cervical topography on the crestal bone resorption and immediate implant survival.

The aim of the study was the investigation of the survival rate of immediate implants in addition to the evaluation of the level of the alveolar bone around the neck region of immediately placed implants of different macrodesigns. To address the question whether the "biological", highly polished area of the implant neck is more associated with crestal resorpiton than the rough neck region, the influence of the surface characters of the implant cervical region was studied. The survival rate of 129 implants from 52 patients was evaluated on different time points after immediate implantation. The level of peri-implant bone contacts to the implant border from 24 implants, which included implants types Tiolox, NobelReplace Tapered and PrimaConnex Tapered, was measured radiographically in seven patients who received immediate implants followed by a healing period of 3-6 months. Various periods from the time of insertion were considered for the measurement depending on the clinically available data. No differences in the status of the alveolar crest around highly polished and roughened cervical-implant regions were observed in the seven patients. The most noticeable resorption was detected in the distal margin of the alveolar crest. The present study shows that highly polished- or roughened neck implants are inserted into a fresh extraction socket do not differ significantly in the clinical and radiographical outcomes after various post-operative periods.

A 3-year clinical and radiographic study of implants placed simultaneously with maxillary sinus floor augmentations using a new nanocrystalline hydroxyapatite.

The aims of this case series was to evaluate the success rate of implants and their restorations, the sinus bone graft resorption, and the marginal bone loss around the implants when nanocristalline HA embedded in a silica matrix was exclusively used as grafting material. In 13 partially edentulous patients of a private practice having missing teeth in the posterior maxilla and a subantral bone height between 3 and 7 mm, 19 sinus augmentations (100% Nanobone, Artoss, Rostock, Germany) by the lateral lift technique were performed. The implants (Tiolox/Tiologic Implants, Dentaurum, Ispringen, Germany) were simultaneously placed. After 6 to 9 months 37 implants were restored with fixed dental prostheses. The clinical evaluation included peri-implant parameters, periotest measurements and the restorations. The radiographic bone heights over time were estimated with linear mixed models. The implant success rate was 100% after three years. The periotest values (between -7 and -6) after implant abutment connection indicated a solid osseointegration. The mean rates of the marginal bone loss over the first year were higher (mesial: -0.55, distal: -0.51 mm) than the annual rates thereafter (mesial: -0.09 mm, distal: -0.08 mm). The mean rates of changes in the total bone height were neglectable (<0.2 mm) and not significant. The prosthodontic and esthetic evaluation revealed a successful outcome. Within the limits of this clinical report it may be concluded that maxillary sinus augmentation using 100% nanocristalline HA embedded in a silica matrix to support implants is a reliable procedure.

Load transfer by fine threading the implant neck--a FEM study.

Osseointegration of dental implants up-to-date is a well-confirmed phenomenon, however the long-term stability and integrity of the bone and soft tissue collar is under discussion. A homogenous distribution of the bone loading is a prerequisite for bone modelling and preservation in the neck area while overload must be avoided. Based on the finite element method (FEM) models of implants without and with a fine thread (implant types Tiolox and tioLogic) with surrounding bone were generated and analysed using the FE program system MSC.Marc/Mentat. The alveolar bone was considered to be an idealized segment with a cortical bone thickness of 2 or 3 mm, respectively with an enclosed spongy bone. The implants were loaded with forces up to 300 N in two different directions, in the first case with a purely vertical force and in other case with an additional lateral force component with a angle of 45 degrees with respect to the occlusal plane. The deflections of the implants ranged from 0.004 to 0.017 mm in the load direction, depending on the implant diameter and the cortical bone thickness. When considering a physiological vertical load of a maximum of 100 N, the highest strains were about 2100 micro strain in the spongy bone. Within the fine thread in the neck area of the implant, the maximum stresses were increased in the cortical bone by 3%. The improvement of implant anchorage in the cortical bone reduced the strains in the spongious bone, at the same time there were no additional stress peaks visible at the fine thread region.

Comparative animal study on hard tissue integration and bone formation of different Nobel Biocare implants.

Dental implantation aims at optimal and long-term hard tissue integration. Beside primary stability, loading time and other factors, e.g. the surface of the endosteal part of the implant, is a matter of special importance. In this animal trial, hard tissue integration of two different implant types was studied using radiological, histological and histomorphometric analysis. Two different implants with an oxidized surface (TiUnite; Nobel Biocare AB, Goteborg, Sweden, NobelReplace Tapered Groovy 4.3 x 10 mm and Replace Select Tapered 4.3 x 10 mm) were inserted into the right and left mandibles of 10 German domestic pigs between canine and premolar and immediately provided with a ceramic crown. The primary implant stability was determined using resonance frequency analysis. After 70 days, the test animals were killed and specimens were collected for histological and histomorphometric examination. All implants showed good primary stability after surgery. Histological and histomorphometrical analysis revealed no significant differences in the bone apposition. The immediate loading of the different implant types don't have any negative effects on the bone apposition in the period of 70 days. The long-term effects of immediate loading of these types of implant requires further studies.

Different bone sesitivity to malformations induced by procarbazine in fetal rats.

The study aimed at to induce cleft-lip-alveolus-palate (CLAP) applying procarbazine in rat fetuses at the 14(th) day of pregnancy, to supply thiocyanate and/or folic acid sufficient for preventive treatment and subsequently to investigate cleft extent in the palatal area as well as bone maturity. In this animal model, female primiparous inbred rats (LEW.1A) were used. The gravid animals were separated into treatment groups: group K (control), group P (procarbazine), group TP (thiocyanate and procarbazine) and group FTP (folic acid, thiocyanate, procarbazine). The results reveal that procarbazine may induce clefts in the palate area. Clefts occurred most frequently in group TP and mainly comprised subtotal clefts of the posterior secondary palate. As for palatal length, group FTP displayed the longest palate which was significantly different only from group K. A different picture was shown for the secondary palate with group TP displaying the shortest values which were significantly different from those in groups K, P, and FTP. Thus, group TP showed the most marked negative changes both for cleft frequency and palatal length as compared to group K and the other groups. The preventive application of either thiocyanate (TP) or thiocaynate and folic acid combined (group FTP) failed to completely prevent cleft formation in the palate area. In conclusion, a preventive effect on palatal clefts and growth inhibition could not be proved for the vitaminoid thiocyanate.

Investigations about N-aminopropyl transferases probably involved in biomineralization.

Polyamines are widespread distributed all over in living organisms. In Thalassiosira pseudonana 10 N-aminopropyl transferase like nucleotide sequences exists. It is assumed that these sequences are involved in the biomineralization of the diatom shell. The cDNA of the sequences were cloned, recombinant overexpressed and assayed with decarboxylated S-adenosylmethionine and several radioactive labelled polyamines. However, only a spermidine synthase and a thermospermine synthase were found to be enzymatically active in an in vitro assay. Both enzyme activities could be recognized in the crude extracts of Thalassiosira pseudonana and Cyclotella meneghiana. In further investigations the kinetics of the thermospermine synthase was determined and a site-specific mutagenesis of the bindig cavity of decarboxylated S-adenosylmethionine was carried out.

Cell passage and composition of culture medium effects proliferation and differentiation of human osteoblast-like cells from facial bone.

Cells loose their capability to multiply and to differentiate when they are serial subcultivated. However, both, multiplication and differentiation are of utmost importance to obtain sufficient amounts of cells for the translation of tissue regeneration into cell based therapeutic approaches. Thus, for the clinical application more information about ideal culture conditions are necessary. Therefore, aim of this study was to assess culture conditions of human osteoblast-like cells during long-term culture focusing on effects of different culture media and ascorbic acid. Biopsies of maxilla and mandible were obtained from 17 patients to test different cell culture media and from 10 patients to analyse differentiation and proliferation related to number of subcultures and ascorbic acid content. Histochemical and immunhistochemical tests (EZ4U assay, ALP histochemistry, type I collagen immunohistochemistry, osteocalcin Elisa) were performed to determine cell proliferation and differentiation. Opti-MEM with 10% FCS produced statistically significant the highest increase in cell counts. The highest proliferation rate in long-term cultivation was seen in the 4th cell passage. A reciprocal relationship between cell proliferation and differentiation over 5 passages with a turning point in the 4(th) passage was found. An ascorbic acid content of 50 microg/ml triggered an optimal increase in differentiation. For osteoblast-like cells, Opti-MEM with 10% FCS proved to be the best culture medium. After 3 passages there is the highest amount of cells with osteogenic differentiation which is enhanced by the addition of ascorbic acid. This approach is suitable for tissue engineering of bone grafts.

Long term evaluation of biomaterial application in surgical treatment of periodontosis.

Regenerative treatment of periodontally damaged teeth is a demanding task. Advantages which comes with use of biomaterials are mainly connected with fact that traditional, surgical treatment protocols often do not lead to bone regeneration. The aim of this research was to evaluate clinical and radiological effectiveness of surgical periodontal treatment (with application of HA-Biocer, Biogramu, Bio-Oss) after eight years prior to surgical protocol. Clinical evaluation consisted of measuring pocket depths with perio probe, than evaluation of API (approximal plaque-index) hygiene index (-). Calculation of modified sulcus bleeding index - SBI (%) by Muhlemann and Son was done. Engelberger, Marthaler and Rateitschak index on xrays was calculated. Routine check up eight years after surgical treatment of periodontitis with use of biomaterials was conducted on 32 patients (20 woman, 12 men). The group of patients was divided into: 28 patients with chronic periodontitis (CP), and 4 patients with general aggressive periodontitis (GAP). Eight years after surgical treatment increase of bleeding areas were observed - in all applied biomaterials. For Bio-Oss average percent of SBI 45.2% (+/-24.3), for Biogran 62% (+/- 36.2) and respectively for HA-Biocer 51% (+/-33.2) API index (%) on teeth proximal surfaces was estimated for Biogran 47%, BioOss - 46.5% and for HABiocer 45.6%. Mean pocket depth (mm) has decreased - in case of all applied biomaterials. Radiological index was also calculated. Decrease of index value was stated. Outcomes of 8 years study indicate, decrease of oral hygiene, increase bleeding, decrease of Engelberger, Marthaler, Rateitchak index. It is necessary to perform routine check up of and control on oral hygiene. It seems to be important to mobilize patients to preserve high oral hygiene.

Evaluation of shape and size changes of bone and remodelled bone substitute after different fixation methods.

Suitable tissue fixation is indispensable to histological analysis. This investigation, therefore, sought to evaluate changes of shape and size of bone specimens and remodelled bone substitute material following different fixation methods. Mandibular bones of 9 pigs (Sus scrofa domesticus) served as specimens. Two mandibular premolars were extracted respectively and the extraction alveoli were filled with synthetic bone substitute material. The samples were collected after 70 days. Fixation of 6 specimens respectively was done for 7 days in 4% formalin (formaldehyde), 70% ethanol and glycerol at 18 degrees C room temperature. The samples were radiographically examined before and after fixation using a reference specimen and subsequently underwent histological analysis. After fixation in formalin, the samples showed no size changes. After fixation in glycerol, morphological analysis revealed minor shape changes. Fixation in ethanol causes shrinking of the tissue specimens. Histological inspection of the tissues shows no morphological changes except slight shrinking. In conclusion there is no universal fixative that could met all requirements and permited proper examination without affecting tissues or bone specimens.