Nataša Ihan Hren

A novel method of dental panoramic tomogram analysis: a perspective tool for a screening test for osteoporosis.

OBJECTIVE The purpose of this study was to test a new method of dental panoramic tomogram (DPT) analysis to show the differences of mandibular bone volume and relative bone density (RBD) in order to detect osteoporosis. MATERIALS AND METHODS A case-control study compared 62 women with osteoporosis (O) and 24 women with osteopenia (o) to a control group of 33 women with normal bone mineral density (N). DPTs were analyzed using an original method resulting in anatomic and RBD indexes as well as using previously described methods: panoramic mandibular index (PMI) and mandibular cortical width (MCW). RESULTS One anatomic and four RBD indexes differed statistically significantly between the group O and N and three RBD indexes differed statistically significantly between o and N. PMI did not show statistically significant differences between the groups. The MCW differed significantly at two measured sites between O and N. CONCLUSIONS Average values of RBD indexes were statistically significantly different between O and N and also between o and N. Important differences regarding RBD were confirmed using a new and original method of common DPT analysis. This method could serve as a screening tool for osteoporosis.

Influence of surgical treatment and radiotherapy of the advanced intraoral cancers on complete blood count, body mass index, liver enzymes and leukocyte CD64 expression

Influence of surgical treatment and radiotherapy of the advanced intraoral cancers on complete blood count, body mass index, liver enzymes and leukocyte CD64 expression Background. The aim of our study was to evaluate the influence of the surgery and radiotherapy of the advanced oral squamous cell carcinoma on the complete blood count, body mass index (BMI), acute inflammatory response, liver enzymes and expression of the CD64 index on leukocytes in the peripheral blood. Patients and method. Venous blood was obtained from 16 patients with advanced oral squamous cell carcinomas treated with radical surgery and external beam radiotherapy. Blood samples were collected prior to surgery (T1), after surgery (T2) and after radiotherapy (T3). Blood samples were analyzed for whole blood count, immunoglobulin G levels, liver enzymes (transaminases (ALT and AST) and gamma-glutamyl trasferase (γ-GT)), inflammatory response markers (C-reactive protein, erythrocyte sedimentation rate, albumin, white blood count, leukocyte count and CD64 expression on leukocytes). Assessment of nutrition was done by calculating the body mass index. Results. Surgery caused anaemia, trombocytosis, leukocytosis, lymphopenia, rise in acute phase proteins, elevation of CD64 expression on monocytes and neutrophyls, elevation of liver transaminases and lowering of γ-GT, albumin, protein and bilirubin levels. After radiotherapy haemoglobin, leukocytes, C-reactive protein, erythrocyte sedimentation rate, liver transferases, albumin, bilirubin and proteins returned almost to T1 levels, levels of lymphocytes, γ-GT and body mass index lowered. IgG levels remained almost unchanged at T2 and T3. Levels of the CD64 expression on monocytes and neutrophyls also elevated after radiotherapy. Conclusions. Surgery caused a significantly larger acute phase response than radiotherapy, while radiotherapy worsened the already present lymphopenia.

Modified bone density-dependent orthotropic material model of human mandibular bone

The prediction accuracy of computational simulations of various biomechanical problems of human bones depends on proper modelling of the problem geometry and boundary conditions but it is also essentially dependent on proper description of the mechanical properties of the all constitutive elements. As the human mandibular bone is a very important load-carrying element in biomechanics, the main aim of this research was to develop an innovative, not yet described in literature, spatial and bone density-dependent orthotropic material model of the human mandibular bone for use in the computational simulations. We compared it with the most used constitutive material models in the computational simulations of the human mandibular bone behaviour with inserted dental implant. The results show that the von Mises equivalent stress distribution values in the bone density-dependent orthotropic model are higher in comparison with other models but the highest are on the top of the alveolar ridge and higher in the lingual than in the buccal part of the lower jaw.

A mouse model of chronic bacterial lesions (a cotton trap) for studying oral bacteria-lymphocyte interactions.

Abstract We established a mouse model of chronic bacterial infection (cotton trap) to get a deeper insight into interactions between immune cells and bacterial strains, that are most commonly isolated from periapical processes. We have used flow cytometry to identify the presence of intracellular cytokines of activated T cells collected from cotton traps, previously infected with different strains of bacteria and implanted subcutaneously into the back of the mice. We provide an evidence that anaerobic bacteria (Bacteroides sp.) and nocardiae are more effective in inducing cytotoxic immunity and Th1 response compared to oral streptococci. Differences in immune response against anaerobic bacteria when compared to streptococci are probably dependent on some non-specific immune cell stimulation (e.g. by bacterial cell wall components), nevertheless the role of specific antigen-dependent immune mechanism can not be excluded.

Immune response in lymphocyte cultures stimulated by oral bacteria preparations.

Abstract Lymphocyte cultures were used as an in vitro experimental model to get a deeper insight into immune response to oral bacteria in periapical granulomas. Lymphocytes isolated from leucocyte concentrate were in lymphocyte cultures stimulated by antigen preparations of oral bacteria. Lymphocyte subsets that have developed in lymphocyte cultures after a week of stimulation were analysed by flow cytometry. A significant increase in expression of INF-γ molecules in CD3+ cells stimulated by antigen preparations of oral streptococci was found, compared with negative control. On the other hand we observed a significant increase in expression of IL-4 in CD3+ cells stimulated by antigens of anaerobic bacteria, compared with negative control. Our results show that antigens of oral streptococci in in vitro lymphocyte cultures induce the differentiation of T helper cells into Th2 cells and that antigen preparations of anaerobic bacteria induce the differentiation of T helper cells into Th1 cells. Furthermore, an increased expression of HLA-DR molecules on CD8+ T cells stimulated by antigens of oral streptococci was found, compared with negative control

MANDIBULAR OSTEOPOROTIC FRACTURE: A CASE REPORT

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Immune response in chronic periapical parodonititis

Abstract The purpose of our study was to investigate the immune response in chronical periapical parodontitis (CPP) by using multidisciplinary approach. 30 CPP samples were obtained after surgical removal - apicoectomy. Each CPP sample was examined by histological, bacteriological and flow cytometrical (FC) analysis of lymphocytes infiltrating CPP samples. Ten percent of bacteriological samples were sterile, others had significant aerobic and anaerobic growth. We used patohistologic and microbiologic findings and compare them to the results of imunological analysis. By FC we found a significant increase in proportions of T lymphocytes expressing interleukin-2 receptors and ICAM-1 compared to peripheral blood lymphocytes. Proportions of T helper cells that produce interferon-gama (IFN-gamma) was higher in CPP samples predominantly colonized by anaerobic bacteria. There were no differences in IL-4 expression by T cells in both groups (anaerobic and streptoccoccal). Among anaerobic CPP samples differences in proportion of T cells that express IL-2 receptors expression was also found between samples colonised by P. acnes and Bacteroides sp. Oral streptococci cause relatively limited tissue destruction and induce Th2 type of immune response accompanied by non-cytotoxic inflammatory reaction. On the contrary, anaerobic bacteria induce Th1 type of immune response that cause more severe inflammatory reaction (type 4 of hypersensitivity that damage the tissue by the action of cytotoxic T cell activation.

Implant-prosthetic rehabilitation after radiation treatment in head and neck cancer patients: a case-series report of outcome

Abstract Background Slovenia has a high burden of head and neck cancer. Patients are mostly treated with surgery followed by radiation therapy. Advanced surgical and prosthodontic techniques have expanded the rehabilitation options. The aim of the study was to review the outcome of implant-prosthetic treatment after radiation therapy. Patients and methods Twenty irradiated head and neck cancer patients who received a removable implant-supported denture at the University Medical Centre Ljubljana were included in the study. Kaplan-Meier survival analysis, Cox proportional hazard models and logistic regression were used to assess the implant survival and success rate. Results Twenty patients had 100 implants inserted. The estimated implant survival rate was 96% after 1 year and 87% after 5 years. Failures were mostly observed before loading (91.2%). Implants inserted in the transplanted bone were significantly more likely to fail. Out of 89 implants supporting the dentures, 79 implants (88.7%) were successful, meaning that they were functionally loaded and exhibited no pain, radiolucency or progressive bone loss. Prosthetic treatment was significantly less successful in older patients. The attachment system and the number of implants did not have a statistically significant influence on the success rate. Conclusions Implant-supported dentures have been shown to be a reliable treatment modality after head and neck cancer surgery and radiation therapy. Possible early failures should be communicated with the patients.

Interdisciplinary treatment of ectodermal dysplasiawith oligodontia: review and case report

Background: Ectodermal dysplasia (ED) is a group of hereditary diseases with disorders in the development of two or more ectodermal structures, such as hair, teeth, nails and sweat glands. The symptoms of craniofacial anomalies express themselves with a larger number of unerupted teeth – oligodontia. Facial characteristics appear because of disorders in the growth of facial bones due to congenitally missing teeth related to underdeveloped alveolar ridge. Treatment planning in these patients requires interdisciplinary approach, and should include various possibilities of substitution of congenitally absent teeth, orthodontic treatment, orthognatic surgery, skeletal augmentation, surgical insertion of dental implants, prosthetic rehabilitation and genetic counseling. Case presentation: In a patient with ectodermal dysplasia, clinical examination and analysis of panoramic x-ray revealed 17 congenitally absent permanent teeth with extensive atrophy of the alveolar ridge, hypotrichosis, narrow face, prominently expressed chin with speech and mastication difficulties. Rehabilitation planning included an extensive interdisciplinary approach with orthodontically guided three-dimensional correction of the upper and lower jaw relationship that was followed by a surgical open lift of the sinus floor on the right side and insertion of four dental implants. In the mandibular arch, the missing teeth were replaced with a metal-porcelain bridge on the supporting teeth and with two bridges supported on the dental implants in the maxillary arch. After 12 years of interdisciplinary treatment the patient was successfully rehabilitated. Conclusion: Treatment of patients with ectodermal dysplasia and oligodontia is individual and must be targeted mainly at prevention, for it is necessary to conserve the patient’s own teeth and at the same time replace (the) missing tissues and teeth, and correct the facial structures.

Prelaminated temporal fascia free flap for reconstruction of the floor of the mouth

Background: Mucosal defects after resection of the malignant disease in oral cavity can be left to heal by secondary intention, covered with free skin grafts or covered with local, regional or microvascular flaps. Decision about reconstruction depends on the defect size, quality of surrounding tissues and the patient’s general health condition. The goal of reconstruction is to achieve elastic, soft and moist surrounding, which enables the functioning of the remaining structures in the oral cavity as well as a rapid functional and social rehabilitation. Methods: At the beginning of patient’s diagnostic workup, two pieces of clinically healthy buccal mucosa were harvested and transferred as free mucosal grafts under superficial temporal fascia. After three weeks, squamous carcinoma of the floor of the mouth was resected and mucosal defect was reconstructed with a prelaminated temporalis fascia microvascular flap. Results: Presented and discussed is a reconstruction of the oral mucosa defect rarely described in the literature. Conclusion: There is no ideal replacement for the oral mucosa. Scar as a result of healing by secondary intention prevents tongue mobility. The quantity of mucosa available for local flaps is limited. Oral cavity environment is not ideal for healing of split-thickness skin grafts and skin transferred into oral cavity is never accustomed to the local conditions. With buccal mucosa prelaminated temporal fascia, microvasculary transferred into the oral cavity, offers a valuable method of reconstruction of medium-size mucosal defects of the oral cavity in selected, motivated patients.