Gene polymorphism of interleukin-1 alpha and beta in keratocystic odontogenic tumors.

AIM AND BACKGROUND: Odontogenic keratocysts have a different growth mechanism and biologic behavior in comparison with more common dentigerous and radicular cysts. It was reclassified as keratocystic odontogenic tumor (KCOT). The proliferative activity of the epithelial cells of KCOT has a close relationship with tissue levels of interleukin-1 (IL-1). Moreover, IL-1 increases the expression of several matrix metalloproteinases in the fibroblasts of adjacent stroma and activates the osteoclastogenesis process. So it plays an important role in the activity, spread, and local aggressiveness of this tumor. Therefore, it seems that the gene polymorphism of the cytokines of the IL-1 family is influential in the pathogenesis of KCOT and the patients' susceptibility to disease. METHOD: A total of 38 blood samples of patients suffering from KCOT and 150 blood samples of healthy patients were assessed using PCR-SSP. The blood samples were assessed for the following polymorphisms: interleukin-1 alpha (-889) and interleukin-1 beta (-511). Following up the patients, we found six recurrent and one syndromic cases. FINDINGS: By comparing the case and control groups, we observed the significant dominance of allele T over C, and genotype TT over CC and CT in IL-1α, although no significant difference was seen in the allele frequency and genotypes regarding IL-1ß. CONCLUSION: The function of IL-1α has a significant relationship with KCOT. Its effective genotype associated with pathogenesis, growth, local invasion, and recurrence is TT.

Unusual Case of External Juxta Coronal Odontoma.

Odontomas are benign tumors of jaws with mixed tissue, which are the result of proliferation of odontogenic epithelium and mesenchymal cells. They occur almost centrally and seldom peripherally. There is no report of such a lesion externally while attaching a tooth crown. In this case, we present a lesion on the buccal surface of the right maxillary central incisor crown, which is misconstrued with a dental overgrowth. Such cases may confuse diagnosis during clinical examination. Radiographically, such odontomas may be mistaken for various other lesions. Ultimate diagnosis should be relied upon microscopic evaluation and histopathological results.

Mel-CAM Expression in Common Oral Carcinomas.

STATEMENT OF THE PROBLEM: Mel-CAM (CD146, MUC18) is a 113-kD heterophilic cell-cell adhesion glycoprotein found in normal and tumoral tissues. The biologic functions and role of the Mel-CAM can be employed as a diagnostic marker in pathology. PURPOSE: The aim of this study was assessing the expression of Mel-CAM in common oral carcinomas like salivary gland mucoepidermoid carcinoma (MEC) and oral squamous cell carcinoma (OSCC) to differentiate the OSCC from high-grade MEC. MATERIALS AND METHOD: This study was performed on 19 specimens of MEC and 17 specimens of OSCC, which were retrieved from the archive of Department of Pathology of Taleghani Hospital, Tehran, Iran. Immunohistochemical staining was performed by using antibody against CD146. The data were analyzed using SPSS software through Mann-Whitney, Spearman's correlation coefficient, and Kruskal-Wallis tests. RESULTS: Mel-CAM was expressed in all MEC samples and 10 OSCC cases. The two groups were significantly different regarding the CD146 expression (p= 0.035). Furthermore, the CD146 expression was found to be significantly correlated with the invasion mode (p= 0.002), tumor size (p= 0.012), and histological grade (p= 0.024) in OSCC group. No significant correlation existed between the expression, intensity, and location with the histological grade of MEC (p> 0.05) nor was any significant correlation detected between the CD146 expression and lymph node metastasis in neither group. CONCLUSION: Regarding the significant correlation between the CD146 expression and the prognostic factors in OSCC, this marker may predict the prognosis in OSCC patients, but not the MEC lesions. It cannot be used for differentiating high-grade MEC and OSCC.

Anti-Cancer Effects of Traditional Medicinal Herbs on Oral Squamous Cell Carcinoma.

BACKGROUNDS: Oral squamous cell carcinoma (OSCC) is among the most frequent oral cancers in individuals under 40. Documents have endorsed that a diet enriched with fruit and vegetables can banish the risk of developing major cancers. This study aimed to evaluate the effects of different concentrations of four medicinal herbs including saffron, ginger, cinnamon and curcumin on OSCC cell line. METHODS: Having obtained the aqueous extract of the four herbs, they were administered on OSCC cell lines per se and in dual, triple, and quadruple combinations. Their effects were measured in different concentrations and in 24 and 48 hours by using MTT assay. RESULTS: The minimum and maximum effective concentrations were respectively 108 and 217 mg/ml for curcumin with IC30 of 77mg/ml, 108 and 270 mg/ml for ginger with IC30 of 58 mg/ml, 2 and 10 mg/ml for saffron with IC30 of 1.9 mg/ml, and 5 and 40 mg/ml for cinnamon with IC30 of 3.3 mg/ml. The best effect of the combinations was seen for cinnamon-saffron after both 24 and 48 hours and the four herbs combination after 48 hours. CONCLUSION: Although all the four herbs were effective on OSCC cell line, the strongest extract was saffron, followed by cinnamon. Combination of cinnamon-saffron and combination of the four herbs showed maximum effects. These findings suggest that traditional medicinal herbs may potentially contribute to oral cancer treatment; providing new windows for the development of new therapeutic strategies for OSCC.

Effectiveness of Methylene Blue in the Prevention of Stifle Joint Arthrofibrosis in Rabbit Models.

BACKGROUND: One of the major challenges in orthopedic surgery is the prevention of arthrofibrosis, which can be successfully alleviated in its early stages. Many studies suggest the administration of methylene blue (MB) as an accessible and effective agent for the prevention of post-operation adhesions. The purpose of this study was to evaluate the efficacy of MB in the prevention of arthrofibrosis. METHODS: This study was conducted on 18 New Zealand white female mature rabbits. The anterior cruciate ligament of the left stifle joint of each animal was cut during aseptic surgery. In the next step, the rabbits were divided into three groups based on their treatments. The rabbits in the first, second, and third groups were subjected to the injection of normal saline, 1% MB solution, and 2% MB solution into their synovial space, respectively. The postoperative stifle range of motion was measured every week. After 4 weeks, the animals were euthanized and all joints were dissected for histopathology. RESULTS: The histopathological evaluation of tissues indicated the presence of fibrotic connective tissue as a sign of fibrosis in all groups. The fibrosis rate, inflammatory rate, tissue disarrangement, fibroblastic cellularity, and granulation tissue formation were at their highest levels in the 1% MB group. The integrity of articular cartilage in the 2% MB group was lower than the other groups. The level of bone degeneration was similar in both MB groups; however, it was more than the control saline group. The range of motion was reduced during the first week, then increased in the second and third weeks, and finally decreased in the fourth week. CONCLUSION: The MB was not an effective method regarding the prevention or treatment of arthofibrosis and the subsequent osteoarthritis. In contrast with previous studies, fibrosis was lower in the high dose MB group, compared to the low dose MB group. The alterations in the range of motion were related to the reduced movement caused by the pain and stiffness of the operated joints. The current study can be considered as the first report addressing the adverse effect of MB on synovial components. LEVEL OF EVIDENCE: I.

Simvastatin vs. L-Carnitine: An experimental study on optimizing nerve repair.

AIM: Complicity and slow rate of axons regeneration necessitates microsurgery that adjuvant therapy can help it. Improving nerve metabolic capacity and response to neural growth factors are positive effects of simvastatin and L-carnitine. To decrease neuronal loss after axotomy and improve neuronal regeneration, this study was designed to assay effects of these agents on nerve repair. MATERIAL AND METHODS: Left sciatic nerve of 70 female rats were cut and repaired under aseptic microsurgery. Based on medications and treatment period, seven groups were formed. CONTROL: no medication. SIM1W: one week daily oral simvastatin. LC1W: one week daily oral L-carnitine. Plb1W: one week daily oral placebo. SIM1M: one month daily oral simvastatin. LC1M: one month daily oral L-carnitine. Plb1M: one month daily oral placebo. Following 90 days, behavioral assessments and then histopathology were done. RESULTS: Mean reflex time of withdrawal reflex latency and toe out angle in all experimented groups increased than normal. Long-term drug-medication significantly improved toe out angle. In long-term drug-medication, inflammation and neural bundle differentiation were significantly lower and higher, respectively. Vascular index showed reduction but number of myelinated nerve fibers had rises in drug-medicated groups compared to control and placebo groups. No obvious differences were detected in myeline diameter. CONCLUSION: Both Simvastatin and L-carnitine can accelerate and improve the process of nerve regeneration in a long enough treatment period. The regulatory influence of these exogenous neurotrophic drugs may be essential to optimize regeneration of nerve fibers; so can broaden horizons for novel therapeutic modalities to decrease neuronal apoptosis.

Ultrastructural and Chemical Composition of Dentin and Enamel in Lab Animals.

STATEMENT OF THE PROBLEM: Human tooth is clinically the most appropriate material that can be used for in-vitro dental research. However, there are limitations and drawbacks for using human teeth. Therefore, alternatives to samples of human teeth for dental studies are necessary. PURPOSE: This study purposed to evaluate and compare the microstructure and chemical composition of enamel and dentin of teeth in some lab animals. MATERIALS AND METHOD: In this experimental study, teeth of mouse, rabbit, guinea pig, dog, cat, and sheep were used. Scanning electron microscope observations and X-ray diffraction analysis were performed on samples. RESULTS: This study revealed resemblance in general structure of dentin and enamel between mentioned animals and human. The minimum mean of dentinal tubules diameter is found in guinea pig (0.5µ), while the highest is in cat (1.5µ). Also the lowest and the highest mean intertubular distance was measured respectively in guinea pig (3µ) and sheep (4.8µ) and the maximum and minimum mean diameter of rods was measured in rabbit (6.6µ) and guinea pig (1.5µ), respectively. CONCLUSION: The recorded details and the measured values indicate great resemblance between dog and human dentin and enamel. Cat is in the second place for dentinal studies; sheep and guinea pig have the least resemblance to human within the scope of the reviewed criteria.

Assessing the Accuracy of Caries Diagnosis in Bitewing Radiographs Using Different Reproduction Media.

STATEMENT OF THE PROBLEM: After introducing digital radiography, practitioners started reading radiographs from computer monitors; however, many still prefer hard-copy radiographs. PURPOSE: This study aimed to assess the possible superiority of either type of radiograph recording media (computer monitor, film, or paper) in diagnosis and perception of the depth of the cariogenic lesions. MATERIALS AND METHOD: Twenty digital bitewing radiographs, obtained from 200 posterior extracted teeth, were displayed on an LG monitor and printed on paper and film using Kodak printers. Two observers independently measured lesions depth on the images. Serial sections of teeth were obtained and the sections were evaluated by a stereomicroscope to determine the actual depth of cariogenic lesions. The efficacy of the each medium was assessed by determining its specificity and sensitivity in comparison with those of histological images. Weighted kappa coefficients and the ROC analysis were used for the statistical analysis. RESULTS: Strong intra- and inter-observer agreements (0.818 to 0.958, 0.77 to 0.85) were found for all detection methods. The highest Az value was obtained with the monitor-displayed images (Az: 0.879); however, differences between detection methods were not statistically significant (p> 0.05). CONCLUSION: Monitor-displayed bitewing radiographs, paper, and film prints used in our study performed similarly in the detection of proximal caries.

Does Adding Silver Nanoparticles to Leukocyte- and Platelet-Rich Fibrin Improve Its Properties?

OBJECTIVES: Leucocyte- and platelet-rich fibrin (L-PRF) membrane can be used in various regenerative treatments. In the case of classical heterologous membrane exposure, microorganisms can be colonized on it and jeopardize the success of treatment. The aim of this study was to compare the antibacterial, mechanical, and histologic characteristics of the L-PRF membrane before and after the addition of silver nanoparticles (SNP). MATERIALS AND METHOD: This study was performed on 10 volunteer men aged 25-35 years. 20 ml whole bloods were collected from each person and L-PRFs were made by routine and SNP modified method. Mechanical, antibacterial, and histological properties were evaluated. RESULTS: The antibacterial efficacy of L-PRF and nanosilver-modified L-PRF was presented as Klebsiella pneumonia had growth on the L-PRF membrane after 12 hours. After 24 hours, Klebsiella pneumonia and Streptococcus viridans had growth on L-PRF and only Klebsiella pneumonia had growth on SNP-L-PRF. The tensile strength and stiffness were significantly higher in the SNP-L-PRF. Precipitation of the SNPs was patchy in the outer layers and quite homogeneous in the inner core. CONCLUSION: Modification of L-PRF with SNP improves the mechanical properties and antibacterial activity of the L-PRF. It can play an important role in regenerative procedures.

Purification of Stem Cells from Oral Pyogenic Granuloma Tissue.

INTRODUCTION: The isolation of stem cells from pathologically damaged dental tissues has been examined only by a few studies. The purpose of this study was to evaluate the possibility of isolation of stem cells from pyogenic granuloma. METHODS: Pyogenic granuloma tissues were enzymatically digested and the resulting single cells were cultured. Then, the cultured cells differentiated into adipocytes and osteoblasts cells. Flow cytometry analyses were performed on markers such as CD 90, CD 73, CD105, CD 45 and CD14. Other features were also analyzed including the effect of colony formation and potentials of differentiation into adipocytes and osteoblasts. RESULTS: The cells derived from pyogenic granuloma tissue formed higher colonies similar to typical spindle-shaped fibroblasts. The cells were positive for mesenchymal markers such as CD 44, CD 271, CD 90, and CD 73, and negative for surface molecules such as CD 14, CD 34 and CD 45. Moreover, they successfully differentiated into adipocytes and osteoblasts. CONCLUSION: The cells isolated from pyogenic granuloma could form CFU fibroblastic units expressing an appropriate marker panel of the cell surface antigen and adequate differentiation potential, all of which met the Cell Therapy International Association criteria for the definition of mesenchymal stromal cells. Pyogenic granuloma contains cells with stem cell properties.

Role of CD146 Enrichment in Purification of Stem Cells Derived from Dental Pulp Polyp.

INTRODUCTION: Hyperplastic pulpitis (pulp polyp) tissues contains cells with stem cell properties similar to that of the dental pulp stem cells (DPSCs). It has also been shown that CD146 enrichment can homogenize the cultures of DPSCs and enhance the colony forming potentials of their cultures. This study determines whether CD146 enrichment can help purifying the stem cells from heterogeneous cultures of the pulp polyp derived stem cells (PPSCs). METHODS AND MATERIALS: Healthy dental pulps and pulp polyp tissues were enzymatically digested and the harvested single cells were sorted according to the presence of CD146 marker. The sorted cells were seeded directly for colony forming unit (CFU) assays of the negative and positive portions. Flowcytometric antigen panel and differentiation assays were used to see if these cells conform with mesenchymal stems cells (MSCs) definition. Differences between the between groups was assessed using independent t-test. The level of significance was set at 0.05. RESULTS: Normal pulp tissue derived cells formed higher colonies (42.5±16.8 per 104 cells) than the pulp polyp (17.75±8.9 per 104 cells) (P=0.015). The CD146 positive portion of the polyp derived cells formed an average of 91.5±29.7 per 104 cells per CFU. On the other hand, CD146 negative portion did not show any colonies (P<0.001). Both resources showed cells with flowcytometric antigen panel and differentiation potentials conforming to MSC definition. CONCLUSION: The entire CFU of PPSCs were formed within CD146 enriched portion. It seems that CD146 enrichment may reduce the number of possible fibroblasts of the pulp polyps and may further homogenize the culture of the PPSCs.

Immunohistochemical Comparison of the Expression of CD34 and CD105 in Odontogenic Keratocyst and Dentigerous Cyst.

STATEMENT OF THE PROBLEM: Odontogenic keratocyst (OKC) is a developmental odontogenic cyst with specific histopathological features, high recurrence rate, and aggressive clinical behavior. Angiogenesis might be considered as an important factor for the growth, expansion, and distribution of this lesion. PURPOSE: The aim of the present study was to determine the mean vascular densities (MVD) of OKCs and dentigerous cysts to evaluate their relationship with the biologic behavior of these lesions. MATERIALS AND METHOD: In this cross-sectional analytical study, angiogenesis was assessed in OKC and dentigerous cyst by measuring the MVD. Immunohistochemistry was carried out using CD34 and CD105. The results were analyzed with independent samples t-test. The data were analyzed, setting p value at 0.05. RESULTS: The MVDs with the use of CD34 and CD105 markers were significantly higher in OKC compared to dentigerous cyst (p< 0.05). In addition, MVDs obtained by CD105 in dentigerous cysts and OKC were significantly less than those based on CD34 (p< 0.05). CONCLUSION: Based on the results of the present study, it can be suggested that angiogenesis might be one of the possible mechanisms involved in higher aggressive biologic behavior and greater recurrence rate of OKC compared to dentigerous cysts.

Antifungal Effects of Common Mouthwashes on Candida Strains Colonized in the Oral Cavities of Liver Transplant Recipients in South Iran in 2014.

BACKGROUND: Among the opportunistic microorganisms, fungi, particularly Candida, play an important role in the mortality of transplant recipients. Thus, controlling and preventing fungal colonizations in various parts of the body, including the oral cavity, can reduce the possibility of post-transplant invasive fungal infections. This can be done simply by using mouthwashes. OBJECTIVES: The current study aimed to determine the prevalence of fungal species of Candida within the oral cavities of liver transplant recipients, and to evaluate the effects on Candida colonization of different exposure times to common mouthwashes. PATIENTS AND METHODS: Specimens were taken from the oral cavities of 101 liver transplant recipients who were referred to our clinic for their first monthly examination. After cultivation and DNA extraction, yeast strains were identified with the RFLP technique. Each strain's susceptibility to 0.2% chlorhexidine, Vi-One, Oral-B, Nanosil D1, and Nystatin mouthwashes was determined based on the CLSI M27-A2 standard method. RESULTS: The obtained data were analyzed using SPSS. Out of 101 samples from liver transplant recipients, 68 cases showed fungi growing within the culture media (67.4%). C. albicans and C. glabrata, respectively, were the first and second most frequent types. Mouthwash susceptibility tests revealed that their antifungal effects over 60 seconds were significantly higher than with an exposure time of 30 seconds. At both 30 and 60 seconds, chlorhexidine was significantly the most efficient. CONCLUSIONS: Chlorhexidine mouthwash with an exposure time of 60 seconds or more is suggested as an effective antifungal agent to be included in the medication regimen of liver transplant patients pre- and postoperatively, in order to prevent fungal colonization and subsequent systemic infections.

MTA1 Expression in Benign and Malignant Salivary gland Tumors.

INTRODUCTION: Salivary gland tumors (SGTs) are important parts of human neoplasms. The most common SGT is pleomorphic adenoma and the most common malignant SGTs are mucoepidermoid carcinoma and adenoid cystic carcinoma (ACC). Metastasis-associated genes 1 (MTA1), a member of the nucleosome remodeling and histone deacetylation complex, is one newly discovered gene which recruits histone deacetylation, causing ATP-dependent chromosome remodeling, and regulating transcription. MTA1 had been shown to be overexpressed in malignant tumors with the enhancement of invasion and metastasis. MATERIALS AND METHODS: Fifty-six samples of salivary gland tumors from the Khalili Hospital archive, including 20 cases of pleomorphic adenoma, 17 cases of mucoepidermoid carcinoma, 19 cases of ACC, and 23 cases of normal salivary gland tissues were chosen for immunohistochemical analysis of MTA1. RESULTS: MTA1 expression in the malignant tumors was significantly higher than that in pleomorphic adenoma (P<0.001), and higher in pleomorphic adenoma than the normal salivary glands(P< 0.001). In total, 69.6% of normal salivary gland tissues showed MTA1, but all cases of salivary gland tumors were positive for MTA1. High nuclear expression of MTA1 was detected in 83.3% (30/36) of the malignant salivary gland tumors and 45% (9/20) of pleomorphic adenoma, while low MTA1 expression was seen in all of the normal salivary gland tissues. No statistically significant correlation was found between MTA1 protein expression and any clinicopathological features (P>0.05). CONCLUSION: Our findings demonstrate that MTA1 was significantly overexpressed in malignant salivary gland neoplasm in comparison to a lower level in benign pleomorphic adenoma, suggesting that MTA1 protein might be involved in carcinogenesis.

Achievement motivation level in students of Shiraz University of Medical Sciences and its influential factors.

INTRODUCTION: Many studies have investigated the relationship between motivation and educational outcomes. The present study was conducted to determine whether the students' motivation in Shiraz University of Medical Sciences (SUMS) decreases during educational years. METHODS: 770 students in SUMS were selected by multi-stage stratified random sampling from each field and entrance year. The first questionnaire contained 57 questions on the effect of economic, social, educational, geographical and personality factors on the students' motivation. The second one was based on 50 incomplete sentences. The validity and reliability of these questionnaires were approved by the experts and Cronbach's Alpha coefficients (85% and 90%, respectively). In this cross-sectional study, ANOVA, t-test and Chi-square tests were applied for data analysis at the 0.05 significance level. RESULTS: Six factors with the most effect on academic motivation were "family attitudes", "getting good jobs in future", "respect for themselves", " the ability to learn", "believing their role in victory and defeat" and "the tendency toward optimism about themselves". In addition, comparing professional doctorate and basic sciences' results revealed no significant relationship between academic motivation and educational years (F=0.819, p=0.397). But comparing field by field showed that Dentistry and Hospital Management and Medical Information (HMMI) had a significant decrease in motivation score by increase in educational years (F=3.991, p=0.015). CONCLUSION: Achievement motivation level in SUMS students was higher than average and did not decrease during educational years. Also, the results showed that personal, social and educational related factors affected motivation level more than economic and environmental factors.

Identification of Mesenchymal Stem Cell Marker STRO-1 in Oral Reactive Lesions by Immunofluorescence Method.

STATEMENT OF THE PROBLEM: Stem cells are considered as new implement for tissue regeneration. Several niches in adult human body are colonized by multipotent stem cells but access to these potential reservoirs is often limited. Although human dental pulp stem cells isolated from healthy teeth have been extensively characterized, it is still unknown whether stem cells also exist in reactive lesions of oral cavity such as pyogenic granuloma and peripheral ossifying fibroma which are deliberated as inflammatory proliferation of different cell families. PURPOSE: The aim of this study was to explore for clues to see whether pyogenic granuloma or peripheral ossifying fibroma contain dental mesenchymal stem cell (DMSC). MATERIALS AND METHOD: Four pyogenic granuloma and four peripheral ossifying fibroma specimens were collected by excisional biopsy and preserved in PBS-EDTA at -86 °C. Then we cut them in 5µm diameter using Cryostat. Having been rinsed with PBS, the samples were stained with a primary mouse anti-human STRO-1 monoclonal IgM antibody. Afterward, a secondary goat anti-mouse IgM-FITC antibody was applied to detect STRO-1+ cells as probable stem cells by immunofluorescence technique. RESULTS: Immunofluorescence microscopy revealed presence of STRO-1+ cells in these lesions, particularly localized on perivascular zone. The negative control group was not glowing. CONCLUSION: Based on these results, it was found that reactive lesions of pyogenic granuloma and peripheral ossifying fibroma have STRO-1 positive cells, which raises the possibility that these cells may be DMSCs.

CD56 Expression in Odontogenic Cysts and Tumors.

Background and aims. Odontogenic cysts and tumors have a wide spectrum of clinical characteristics that lead to the different management strategies. Since definite diagnosis is difficult in some cases, it has been suggested that CD56 may be a candidate marker for definitive diagnosis of some odontogenic tumors. The present study was designed to examine CD56 expression in lesions with histopathological similarities. Materials and methods. In this cross-sectional, analytical study the subjects were 22 ameloblastomas, 13 dentigerous cysts, 10 keratocystic odontogenic tumors (KCOT), 4 adenomatoid odontogenic tumors (AOT), 3 orthokeratinized odonto-genic cysts, 3 calcifying odontogenic cysts (COC) and one glandular odontogenic cyst (GOC). All the samples were examined for CD56 immunoreactivity. Data were analyzed using chi-square test. Results. Twenty cases (91%) of ameloblastomas, 3 (75%) AOT, 4 (40%) KCOT and one case of GOC were positive for CD56. None of the dentigerous cysts, COC and orthokeratinized odontogenic cysts was CD56-positive. There was a significant difference in the CD56 expression between ameloblastoma and dentigerous cyst, as well as COC. Also, KCOT showed significantly higher expression than orthokeratinized odontogenic cyst. Conclusion. In this study CD56 expression was limited to the odontogenic tumors and more aggressive cystic lesions. This marker can be a useful aid for distinguishing cysts and tumors from similar lesions.

Evaluation of histological impacts of three types of orthodontic fixed retainers on periodontium of rabbits.

STATEMENT OF THE PROBLEM: Fixed retainers were developed to maintain incisor alignments after orthodontic treatments. Although the effects of fixed retainers on periodontal health are clinically studied, no studies have still evaluated the histological changes in the periodontium after the placement of thefixed retainers. PURPOSE: The aim of this study was to evaluate the effects of customised retainers on periodontium histologically. MATERIALS AND METHOD: Forty pairs of maxillary and mandibular central incisors of twenty rabbits were randomly divided into four equal groups: The first group was considered as the control and in the second group, Fiber Reinforced Composite (FRC), in the third group, 0.014 inch stainless steel (SS) wire and in the fourth group, 0.175 inch multistrand stainless steel (MSS) wire were bonded on the labial surfaces of the incisors. After sixty days; animals' periodontium were evaluated histologically. RESULTS: The number of bone resorption lacuna in the control group was significantly less than FRC and 0.014 SS groups. The periodontal vessel count and their diameter in the control group was significantly lower than the other groups. The pulp vessel count and their diameter in controls were significantly more than the 0.014 SS and the 0.175 MSS groups. CONCLUSION: Findings of this study suggest that FRC fixed retainer might cause detrimental effects on the periodontal ligaments and supporting bone and the 0.014- inch and 0.175- inch fixed retainers can cause hyalinization and possibly the necrosis of the pulp.

Herpes Zoster Induced Osteomyelitis in the Immunocompromised Patients: A 10-year Multicenter Study.

STATEMENT OF THE PROBLEM: Alveolar bone necrosis induced by Herpes zoster infection is considered as a rare manifestation of osteomyelitis and few case reports are presented in the literature. PURPOSE: The aim of this study was to evaluate mandibular osteomyelitis caused by herpes zoster in the immunocompromised patients with histopathologically documented osteomyelitis in the mandible and herpes zoster infection. MATERIALS AND METHOD: 30 patients were recruited in this cross-sectional study. 19 patients were completely edentulous, 4 patients were partially edentulous and 7 with complete dentition. In all cases, specimens were analyzed using a conventional polymerase chain reaction (PCR) test for varicella zoster virus.  RESULTS: 16 patients underwent dialysis, 9 patients received chemotherapy treatments and 5 patients had transplantation (four kidneys and one liver). Histopathological assessment demonstrated a nonspecific bone necrosis exhibiting an eosinophilic, homogeneous non-vital bone tissue with peripheral resorption surrounded by reactive connective tissue. PCR test was positive in 21 cases. CONCLUSION: This study demonstrated that the frequency of osteomyelitis induced by herpes zoster could be more than the records provided by previous studies. Histopathological findings might be nonspecific in such patients. PCR test was not positive for all HZ induced osteomyelitis patients.

Caveolin-1 expression in odontogenic cysts and ameloblastomas.

OBJECTIVE: The aim of this study is to evaluate the caveolin-1 expression in a group of odontogenic cysts and tumors. MATERIAL AND METHOD: In this cross-sectional study, the expression of caveolin-1 was evaluated immunohistochemically in 75 samples including 18 cases of dentigerous cyst, 18 odontogenic keratocysts, 3 orthokeratinized odontogenic cysts, 2 calcifying odontogenic cysts and 34 ameloblastomas (solid and unicystic). RESULTS: Positive immunohistochemical reaction was found in 100% of odontogenic cysts and this was significantly more than both unicystic (65%) and solid (55%) ameloblastomas. CONCLUSION: The present study showed the expression of caveolin-1 in all odontogenic cysts and more than ameloblastomas. The results suggested that absence of caveolin-1 might enhance aggressiveness of odontogenic lesions and could be a useful marker for distinguishing ameloblastomas from other odontogenic lesions.