Radovan Slezák

Influence of the orientation of the Osstell transducer during measurement of dental implant stability using resonance frequency analysis: a numerical approach.

Stability of dental implants is measured by means of the Osstell device using a method of resonance frequency analysis. The aim of the study was to evaluate the role of direction-dependence of the Osstell transducer. For this purpose, a set of parametrical finite element analyses has been used. When rotating the transducer around the vertical axis the crucial phenomenon is the change in behavior of the system, which occurs in positions between 30 degrees and 80 degrees to the long axis of the alveolar crest. It seems from the presented results that, when measuring approximately perpendicularly to this long axis, the deviation from the ideal perpendicular position must not exceed 30 degrees. In this case, the first resonance frequency is recorded. When measuring in the approximately parallel position to the long axis of the alveolar crest, the second resonance frequency is recorded. The deviation from the ideal parallel position must not exceed 10 degrees. These values are not comparable with the previous ones.

A retrospective study of 171 patients with oral lichen planus in the East Bohemia - Czech Republic – single center experience

Objectives: Oral lichen planus is chronic inflammatory disease with a high prevalence in the population. This study describes the epidemiological and clinical characteristics of group of patients with oral lichen planus in the Czech Republic. Material and Methods: Data was taken from the medical records of 171 patients referred to the Oral Medicine Unit at the University Hospital in Hradec Králové with histologically confirmed clinical diagnosis of oral lichen planus in the period 2003 – 2013. The data were retrospectively reviewed. Results: Of the 171 patients, 116 (67.8%) were women and 55 (32.2%) were men. The mean age was 55.2 ± 12.4 years (range of 85.0 – 20.9). The reticular form was the most frequent 93.6% (160 pts.), desquamative gingivitis was 12.9% (22). The buccal mucosa was the site most affected 89.5% (153 pts.). The lesions were asymptomatic in 52 patients (30.4%). Extraoral lesions were observed in 20.5% (35 pts.) of the patients, skin involvement was in 16.4% (28 pts.). Smokers were 29 patients. Local treatment used 116 (67.8%), only 6 patients used systemic short tome corticoid therapy. No evidence between OLP and malignant transformation was observed. Conclusions: This retrospective study show very similar profile and clinical features of the patients with OLP as in other studies. Key words:Oral lichen planus, clinical features, extraoral manifestation.

Expression of Matrix Metalloproteinase 9 in Patients with Oral Lichen Planus

INTRODUCTION Oral Lichen planus (OLP) is chronic inflammatory oral mucosal disease of unknown etiology. Basement membrane damage and T-cell migration in OLP may be mediated by matrix metalloproteinases (MMPs). We examined the expression of matrix metalloproteinase 9 to support this hypothesis. MATERIALS AND METHODS The study population consisted of 71 patients with OLP and 10 control patients with oral fibromas. Indirect immunohistochemistry was used for detection of MMP 9 expression (polyclonal rabbit anti-human MMP antibody). RESULTS In all cases of OLP, the MMP-9 expression was seen mainly in the area oflymphocytic inflammatory infiltrate in the lamina propria including lymphocytes within the overlying epithelium. In addition, it was observed in the epithelial keratinocytes, particularly in the stratum basale and stratum spinosum with occasional positivity in the superficial layer. Fibroblasts and endothelium of small vessels in the lamina propria showed MMP9 expression as well. In all cases of oral mucosal fibromas, the MMP-9 expression was seen only in fibroblasts and in endothelium of small vessels with occasional positivity within the overlying epithelium. It remains unclear, whether MMP-9 is directly connected to OLP pathogenesis.

B Cell Toll-like Receptors with Respect to the Pathogenesis of Sjögren’s Syndrome

Sjögrens syndrome (SS) is a chronic autoimmune immunopathological disease of unknown aetiology. It is characterized by focal lymphocyte infiltration and inflammation in exocrinne glands, involving especially salivary and lacrimal glands. Hypofunction of the glands leads to the decreased glandular secretion together with impaired production of saliva and tears, resulting in dryness of the mouth and eyes (xerostomia and xerophthalmia, respectively). Some of the studies have suggested that Toll-like receptors and B cells play a pivotal role in the pathogenesis of autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis and SS etc. Stimulation of B cells via the TLRs pathway leads to several important changes including increase in antibody production, differentiation to plasma cells, cytokine production and up-regulation of molecules essential for antigen presentation to (autoreactive) T cells. Experimental data support the idea that co-engagement of BCR and TLR might be sufficient for B cell activation and lead to the failure of tolerance. In human naive B cells, most TLRs are expressed at very low or undetectable level, but expression of TLR 7 and 9 is rapidly induced by B cell receptor triggering. This review will focus on the possible role of B cells and TLRs signaling in the pathogenesis of SS.

Levels of multiple proteins in gingival crevicular fluid and intra-amniotic complications in women with preterm prelabor rupture of membranes

Abstract Objective: The primary aim of this study was to identify the association between the local inflammatory response in gingival crevicular fluid measured by the levels of multiple proteins and maternal and intra-amniotic inflammatory responses measured by maternal serum C-reactive protein (CRP) and amniotic fluid interleukin (IL)-6 concentrations, respectively, in women with preterm prelabor rupture of membranes (PPROM). Methods: A prospective study was performed in which 78 women with singleton pregnancies complicated by PPROM between 24 + 0 and 36 + 6 weeks of gestation were included. Transabdominal amniocenteses were performed at the time of admission. A bedside assessment of amniotic fluid IL-6 was performed. Maternal serum CRP concentration was also measured at the time of admission. Gingival crevicular fluid was collected from the pocket of the selected tooth (the tooth with the deepest pocket) using standard sterile paper strips within 72 h after admission. Twenty-six proteins in the gingival crevicular fluid were assessed by multiplex the Meso-Scale technology. Results: No correlations between the levels of proteins in the gingival crevicular fluid and maternal serum CRP and amniotic fluid IL-6 concentrations were found, except for a weak positive correlation between granulocyte macrophage colony-stimulating factor and CRP. Conclusions: The local inflammatory response in the gingival crevicular fluid is not related to the maternal and intra-amniotic inflammatory responses in women with PPROM.

Cytochrome P450 2D6 polymorphism and drug utilization in patients with oral lichen planus.

Abstract Objective. Oral lichen planus (OLP) is one of the commonest diseases of the oral mucosa. The etiology of the disease is unknown. Our goal was to determine frequencies of functionally important alleles which determine the metabolic rate (phenotype) of individuals with OLP and to compare drug utilization, with focus on CYP2D6, with that of a control group. Material and methods. The study population consisted of 46 patients with OLP, 60 sex- and age-matched control subjects for drug utilization evaluation and 223 healthy non-medicated controls for genotype comparison. DNA analysis was done using polymerase chain reaction and restriction fragment length polymorphism. The gene CYP2D6 was analyzed for the alleles CYP2D6*3,*4,*5,*6 and gene duplication. Drug utilization was evaluated according to Anatomical Therapeutic Chemical code, liver drug metabolism pathway and mono- or polytherapy. Results. Intake of drugs was significantly higher in the group of OLP patients in comparison with control subjects. The use of CYP2D6 substrates, inhibitors or inducers did not differ between OLP patients and controls. Predicted phenotype frequencies in OLP patients and healthy controls, respectively were as follows: ultrarapid metabolizers 2% and 5.8%, extensive metabolizers 52% and 49.8%, intermediate metabolizers 39% and 37.7% and poor metabolizers 7% and 6.7%. Conclusions. We did not find a statistically significant difference in the frequency of CYP2D6 alleles between OLP patients and healthy controls. OLP patients used more medication than age- and sex-matched controls.

Influence of Different Luting Agents on the Marginal Discrepancy of Procera® AllCeram Alumina Crown Copings – An Experimental Study

Two maxillary first molars and two central incisor typhodont teeth were prepared with 0.8 mm chamfer, 2.0 mm occlusal reduction, and 6 degree taper. The prepared teeth were duplicated 9 times to obtain 36 die stone models and divided into three groups (n = 12). Luting agents tested were zinc phosphate, glass ionomer and resin cement. Procera®AllCeram 0.6 mm coping was fixed with a calibrated finger force of 50 N. The absolute marginal discrepancy was measured using the scanning electron microscope on four axial walls with 4 measurements on each wall to obtain a total of 16 readings for one tooth. Mann Whitney U test was applied to find significant differences between luting cements and Kruskal Wallis tests among groups. Results The absolute marginal discrepancies of cements were in reducing order zinc phosphate (AZ) 53 μm; resin (AR) 44.5 μm, glass ionomer (AG) 29 μm. There was a significant difference among luting cements AG V/s AZ (p = 0.001) and AR V/s AG (p = 0.003), except AR V/s AZ (p = 0.213). All axial surfaces except mesial showed a significant difference. Conclusion The study concluded that different luting media have a definite effect over the final fit of AllCeram coping. Absolute marginal discrepancy was within the accepted level of 100 μm. Distal axial surface demonstrated a wider gap among all the luting agents.

Periodontal disease and intra-amniotic complications in women with preterm prelabor rupture of membranes

Abstract Objective: Periodontal disease is frequently suggested as a possible causal factor for preterm delivery. The link between periodontal disease and preterm delivery is a possible translocation of periopathogenic bacteria to the placenta and amniotic fluid as well as a systemic response to this chronic inflammatory disease. However, there is a lack of information on whether there is an association between clinical periodontal status in women with preterm prelabor rupture of membranes (PPROM) and the presence of microbial invasion of the amniotic cavity (MIAC) and intra-amniotic inflammation (IAI). Therefore, the main aim of this study was to evaluate the incidence and severity of periodontal disease in women with PPROM. The secondary aim was to characterize an association between periodontal status and the presence of intra-amniotic PPROM complications (MIAC and/or IAI). Materials and methods: Seventy-eight women with PPROM at gestational ages between 24 + 0 and 36 + 6 weeks were included in this study. The samples of amniotic fluid were obtained at admission via transabdominal amniocentesis, and amniotic fluid interleukin (IL)-6 concentrations were determined using a point-of-care test. All women had a full-mouth recording to determine the periodontal and oral hygiene status. Probing pocket depth and clinical attachment loss were measured at four sites on each fully erupted tooth. Results: In total, 45% (35/78) of women with PPROM had periodontal disease. Mild, moderate, and severe periodontal disease was present in 19% (15/78), 19% (15/78), and 6% (5/78) of women, respectively. The presence of MIAC and IAI was found in 28% (22/78) and 26% (20/78) of women, respectively. Periopathogenic bacteria (2 × Streptococcus intermedius and 1 × Fusobacterium nucleatum) was found in the amniotic fluid of 4% (3/78) of women. There were no differences in periodontal status between women with MIAC and/or IAI and women without these intra-amniotic complications. Conclusions: The presence of MIAC and IAI was not related to the periodontal status of women with PPROM.

Increase of Intracellular BAFF in B Cells of Sjögren's Patients Is Not Affected by Decrease of BAFFR.

The presence of a broad spectrum of autoantibodies in Sjögrens syndrome (SjS) patients is the result of abnormal B-cell regulation that can be at least partially explained by abnormal BAFF/BAFFR regulation. The objective of this study was to determine both membrane and intracellular expression of BAFF/BAFFR in monocytes and B-cells in peripheral blood of 19 primary Sjögrens syndrome patients and 20 healthy controls using flow cytometry. We also measured sBAFF in serum. Compared to healthy controls, both surface and intracellular expression of BAFF was significantly increased in monocytes and B-cells of SjS patients. Also serum sBAFF level was elevated. Expression of BAFFR on B-cells of SjS patients was surprisingly decreased, but there was no clear increase or decrease within monocytes. Our results indicate that activated monocytes communicate with B-cells via BAFF and BAFFR, so that B-cells are stimulated, but BAFF is also produced to stimulate cells in autocrine way. The decrease of BAFFR expression in SjS patients suggests that there is the mechanism that attempts to take over in order to balance the high level of BAFF.

The Influence of Smoking on Dental and Periodontal Status

Tobacco is one of the major toxic agents in our civilization. It’s use is considered as one of the most common cause of mortality and morbidity in both developed and developing countries in present times. Of 260 million deaths which occurred in the developing world between 1950 and 2000, it is estimated that 50 million were due to smoking. Globally, smoking related mortality is set to rise from 3 million annually (1995 estimate) to 10 million annually by 2030, with 70 % of these deaths occurring in developing countries (Fagerstrom, 2002). Since 1970, smoking prevalence among men has slightly decreased, but among women, teenagers and children, smoking has increased dramatically. Sixty percent of children are exposed to Environmental Tobacco Smoke (ETS) at their homes (Mackay & Amos, 2003). Tobacco is one of the most important risk factor for oral diseases including oral cancer, oral mucosal lesions, periodontal diseases, wound healing failure, dental implants failure, gingival inflammation, acute necrotizing ulcerative gingivitis and apthous ulcers (Vellappally et al., 2007; Jacob et al., 2007). There is substantial evidence suggesting that the risk of oral diseases increase with frequent use of tobacco and that quitting smoking results in reduced risk (Winn, 2001).