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Introduction: Hybrid layer degradation is mainly attributed to matrix metalo proteinases (MMP) activity. In this study, we compare inhibitory effect of nano zinc oxide with chlorhexidine (0.12%) on distraction of collagen scaffolding of the hybrid layer by immunohistochemistry (IHC) and microleakage tests. Materials and Methods: A total of 60 extracted molars and premolar teeth with no caries and visible anatomic defects were selected. Class 5 cavities with dimensions of 2 × 2 × 2 mm was performed for each tooth on the buccal surface 1 mm above cemento enamel junction. Results: In microleakage test, there was no significant difference in the result for groups pretreated with nano zinc oxide mixed with single bond (C), pretreated with chlorhexidine (0.12%) applied before bonding (B) and not pretreated with these agents (A) whether in 24 h or 1-week. in IHC test, there was a significant difference (P < 0.05) between all groups except in group B and group C. Conclusion: (1) The inhibitory effect of chlorhexidine and nano zinc oxide on MMPs activity is different. (2) Microleakage amount is different in composite resin restoration used in a cavity pretreated with nano zinc oxide contained bonding or chlorhexidine 24 h and 1-week later.

Background. Squamous cell carcinoma is a prevalent carcinoma of the oral cavity. Recently anti-proliferative effect of probiotics has been considered and assessed against different cancers. The aim of this study was to evaluate the cytotoxicity of Acetobacter syzygii strain supernatant on KB human oral cancer cell line and KDR human epithelial normal cell line. Methods. The cytotoxicity assessments were performed through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) as well as through qualitative (4',6-diamidino-2-phenylindole staining) and quantitative (flow cytometry assessments using the BD Biosciences Annexin V-FITC Kit) evaluations of apoptosis. Results. A. syzygii secretions exhibited significant cytotoxicity against KB cancer cell lines similar to cisplatin (75.7% apoptosis) while the rate of apoptosis in KDR normal cells was only 9.36%. The prophylactic effects of Lactobacillus acidophilus (PTCC 1643), as a reference bacterium, was similar to A. syzygii , indicating beneficial effects of useful bacteria on prevention of oral diseases. Conclusion. The anticancer bioactivity of A. syzygii strain secretions depends on the induction of apoptosis in KB cancer cells. However, several investigations should be conducted to precisely determine effective compounds to be used as anticancer therapeutics in the future.

Background. Oral mucositis is the chief complication of head and neck chemotherapy. This study was conducted to evaluate Hypozalix artificial saliva and propolis mouthwash efficacy for the prevention of chemotherapy-induced oral mucositis in leukemic patients. Methods. The present double-blind clinical trial was carried out on 72 patients undergoing chemotherapy. The patients were assigned to 3 groups. In the control group, CHX mouthwash and fluconazole were used by the subjects. In groups 1 and 2, Hypozalix and propolis mouthwashes were added to the combination therapy used in the control group. The results were compared between the three groups after 14 days. Results. Mean score A was significantly higher than mean score B in children (P = 0.001). In contrast, mean score A was significantly lower than mean score B in young adults (P = 0.003). Conclusion. Use of Hypozalix spray or propolis mouthwash in association with CHX mouthwash and fluconazole simultaneously at the start of chemotherapy resulted in a decrease in chemotherapy complications after 14 days. In many cases the use of propolis mouthwash yielded better results and the patients exhibited a greater tendency to continue to use it.

Background. Since it is possible for carbamide peroxide (CP) bleaching agent to contact old amalgam restorations, the present in vitro study evaluated the amount of dissolved mercury released from amalgam restorations with various percent-ages of silver content subsequent to the use of 15% CP. Methods. Thirty ANA 2000 amalgam disks with 43.1% silver content and thirty ANA 70 amalgam disks with 69.3% silver content were prepared. In each group, 15 samples were randomly placed in glass tubes containing 15% CP (as experimental groups) and the remaining 15 samples were placed in buffered phosphate solution (as control groups) with the same 3-mL volume for 48 hours. Subsequently, the amount of mercury dissolved in each test tube was measured using Mercury Analyzing System (Cold Vapor Atomic Absorption, MASLO, Shimadzu, Japan). Data was analyzed with two-way ANOVA and a post hoc Tukey test. (α = 0.05). Results. The amount of mercury released after exposure to CP was significantly higher than that released after exposure to buffered phosphate (P < 0.001). In addition, the amount of mercury released from dental amalgam with a silver content of 43% was significantly higher than that released from dental amalgam with a silver content of 69% (P < 0.001). Conclusion. The amount of mercury release is inversely proportional to the silver content of dental amalgam.

Background: Cancer immunotherapy attempts to stimulate the immune system to reject and destroy tumors and is one of the cancer treatment strategies. Recently, interluekin36 (IL36) has been used as immunotherapeutic agents in cancer gene therapy. Present study investigated that the IL36 gene therapy effects on the regression of tumor masses in mouse model. Aim of this study is determination of the gene therapy effects by IL36 in the regression of tumor masses in mouse model., Methods: To study the therapeutic efficacy of this cytokine, WEHI-164 tumor cells were transected with mIL36 plasmids. ELISA test was used to check cytokine production by transected cells. To establish fibro sarcoma mouse model, Tumoral transfected cells were injected subcutaneously to inoculate tumor in BALB/C mice. Tumor volumes were measured by caliper. Mice were sacrificed and tumors were extracted. The expression of IL36 and IFN-γ was studied with Real-time PCR and immunoblotting. The expression of Ki-67 (a tumor proliferation marker) in tumor masses was studied by immunohistochemistry staining. In this study we had 2 groups which are treated with IL-36 and Untreated with IL-36 as a blank., Results: The group treated with IL36 indicated decrease of tumor mass volume (p<0.001). The results of western blotting and real-time PCR showed the IL36 expression increased in the group treated with IL36 (with relative expression of 1.9)., Conclusion: Immunohistochemistry staining indicated that the Ki-67expression has been reduced in the group interfered with IL36. IL36 gene therapy has therapeutic effects on the regression of tumor masses in fibro sarcoma mouse model.

Background and aims. The aim was to evaluate the effect of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on microtensile bond strength (μTBS) to carious affected dentin (CAD) using etch-and-rinse and self-etch adhesive systems. Materials and methods. The occlusal surface of 32 human molars with moderate occlusal caries was removed. Infected dentin was removed until reaching CAD and the teeth were randomly divided into two groups based on the Single Bond (SB) and Clearfil SE Bond (CSE) adhesive systems. Before composite resin bonding, each group was subdivided into three subgroups of ND, CAD and CPP-ACP-treated CAD (CAD-CPP) based on the dentin substrate. After dissecting samples to l-mm-thick cross-sections (each subgroup: n = 13), μTBS was measured at a strain rate of 0.5 mm/min. Data was analyzed using two-way ANOVA, independent samples t-test and post-hoc Tukey tests (α=0.05). Results. Bond strength of both adhesive systems to ND was significantly higher than that to CAD (P <0.001) and CAD/CPP (P < 0.001). There were no significant differences between the μTBS of SB to CAD and CAD-CPP (P > 0.05).μTBS of CSE to CAD-CPP was higher than that to CAD; however, the difference was not significant (P > 0.05). Significant differences were found between SB and CSE systems only with CAD substrate (P < 0.001). Conclusion. Regardless of the adhesive system used, surface treatment of CAD with CPP-ACP did not have a significant effect on bond strength. However, bond strength to CAD was higher with SB rather than with CSE.

Background and Aims: Oral lichen planus is a relatively common chronic oral mucosal disease of unknown etiology. Regarding numerous studies on the immunologic factors involved in the etiology of lichen planus, the present study evaluated the serum interleukin-17 (IL-17) level in patients with erosive and non-erosive oral lichen planus., Materials and Methods: This descriptive analytical study included 24 patients with erosive oral lichen planus (EOLP), 24 patients with non-erosive oral lichen planus (NEOLP) and 24 healthy volunteered as control. Blood samples of the subjects underwent ELISA, using special kits, to determine serum interleukin-17 levels. Data was analyzed using with descriptive statistic, chi-square test, and one-way ANOVA and Tukey post-hoc test with SPSS 16 software., Results: EOLP patients showed a high level of serum IL-17 compared with NEOLP patents and control groups (EOLP=184.16 ± 12.41 pg/mL, NEOLP=106.09±10.78 pg/mL, control=15.50 ± 4.34 pg/mL, P - 0.001)., Conclusion: High level of serum IL-17 in erosive oral lichen planus patients compared to the non-erosive type and healthy individuals may be the reason for higher inflammation and atrophy in the erosive type.

Background: Pemphigus vulgaris, a chronic mucocutaneous disease, is the most prevalent type of pemphigus which manifests with development of bullae and erosions on skin and mucosal membranes., Objectives: To investigate the potential role of IL-23 in pemphigus vulgaris., Methods: In this study, 30 patients with pemphigus vulgaris and 30 healthy individuals were selected according to inclusion and exclusion criteria. Measurement of IL-23 serum levels in blood samples was conducted by ELISA. Data was analyzed using Student's t-test for comparison of IL-23 levels between the two groups., Results: Mean serum levels of IL-23 in patients with pemphigus and healthy controls were 25.1 ± 4.2 and 17.9 ± 4.7 pg/ml, respectively (p<0.05)., Conclusions: Based on the findings of this study, serum levels of IL-23 were higher in patients with pemphigus in comparison to healthy individuals with no clinical significance.

Background and Aims: The role of cytokines in the immunopathogenesis of oral lichen planus (OLP) has received much attention. The aim of this study was to evaluate the serum levels of TNF-α and TGF-β in patients with OLP in an Iranian population., Materials and Methods: Thirty-two patients with OLP and 32 age-matched healthy volunteers as a control group were included in this study. Serum tests including TNF-α and TGF-β was performed in both groups. Data analysis was performed using descriptive statistics and Mann-Whitney U test using SPSS software version 16.0., Results: The mean of TNF-α in study and control groups were 157 ± 115 pg/ml and 14 ± 10 pg/ml, respectively. The difference between the two means was statistically significant (P < 0.001). Moreover, the mean of TGF-β in study and control groups were 155 ± 26 pg/ml and 175 ± 57 pg/ml, respectively. The difference between the two means was statistically significant (P = 0.03)., Conclusion: According to the results of the present study, there was a significant decrease in the serum levels of TGF-β and a significant increase in the serum levels of TNF-α in patients with oral lichen planus. The increase in TNF-α serum levels in patients with OLP explains the inflammatory process in the course of the disease.

Background and Aims: Bacterial contamination of dental unit water supplies (DUWS) has attracted a lot of attention in recent years due to the emergence of serious infectionsin susceptible dental patients. The aim of the present study was to evaluate the presence of gram-negative bacterial contamination in DUWS at Tabriz University of Medical Sciences Faculty of Dentistry., Materials and Methods: This descriptive study was carried out on 51 active dental units in different departments. Con-tamination was determined by taking samples from the unit's water supply before dental procedures and the use of specific culture media. The cultures were evaluated after 48 hours., Results: Gram-negative bacterial contamination was identical in all the departments. In the departments on the ground floor, namely Departments of Periodontics and Oral and Maxillofacial Surgery, Pseudomonas contamination was observed in 71% of units; in the departments on the first floor, namely Departments of Prosthodontics, Orthodontics and Pedodon-tics, 46.8% of the units had Pseudomonas contamination; and in the departments on the second floor, namely Departments of Operative Dentistry and Endodontics, 37.7% of the units demonstrated Pseudomonas contamination., Conclusion: Gram-negative bacterial contamination was evident in the evaluated DUWS. The contamination type was identical but the number of contaminated units decreased with the increase in the height of the floors.

Background and Aims: Lichen planus is a chronic inflammatory disorder with unspecified etiology, appearing as a result of stress, genetic predisposition and immunologic factors. Erosive type of the disease is more important because of its clinical symptoms of pain, irritation and malignancy risk. Despite various medications used, a definite cure for lichen planus is un-known. Regarding the effect of zinc on healing of ulcers, the aim of this study was to compare the effect of a mouthwash with and without zinc and fluocinolone on healing of erosive oral lichen planus., Materials and Methods: Twenty randomly-selected patients with erosive oral lichen planus were divided into two groups of 10. One group received zinc mouthwash with fluocinolone ointment and the other group received placebo with ointment. The largest dimension of the ulcers was measured by digital calipers and the intensity of pain was determined by visual ana-logue scale. Data was analyzed with Mann-Whitney U test., Results: Pain, irritation and lesion surface area decreased in both groups. Decrease in pain severity was identical in both groups (P = 0.11). However, decrease in surface area with zinc mouthwash plus fluocinolone was more than that with only fluocinolone (P = 0.037)., Conclusion: 0.2% zinc mouthwash plus fluocinolone and only fluocinolone were both effective in decreasing pain, irrita-tion, and surface area of OLP. However, decrease in surface area with zinc mouthwash plus fluocinolone was more than that with fluocinolone alone.

Background and Aims: The purpose of this study was to determine efficacy of 19% Elaeagnus angustifolia (EA) topical gel in the treatment of symptomatic oral lichen planus., Materials and Methods: Patients with symptomatic oral lichen planus referring to the Department of Oral Medicine, Fac-ulty of Dentistry at Shahid Beheshti University of Medical Sciences were asked to participate in the study. Twenty-eight pa-tients who were histopathologically diagnosed with lichen planus were divided into two groups (15 in the case and 13 in the control groups). The subjects were randomly assigned to either topical gel of EA or placebo in a double-blind manner. They were then instructed to apply the medication on dried lesions three times daily. Pain and size of the lesions were evaluated after 2 weeks. Data were analyzed by SPSS 12.0 software, using t-test, paired t-test, Fisher's exact test and chi-square test., Results: Twenty-eight patients (m/f: 7/21) with symptomatic oral lichen planus participated in the study. Fifteen patients (m/f: 4/11) received E A gel and 13 patients (m/f: 3/10) received placebo. There was a 75% decrease in pain (33.3% in the case and 7.7% in the control groups), and a decrease of 50% in size (33.3% in the case group) and 75% only in 7.6% of the case group., Conclusion: The results suggest that 19% EA gel is efficient in the treatment of symptomatic oral lichen planus, with anti-inflammatory and analgesic effects, as well.

Low-power lasers are a group of lasers with a power less than 250 mW and unlike high-power lasers they have no effect on tissue temperature; they produce light-dependent chemical reactions in tissues. These lasers have analgesic features with their ability to trigger reactions that reduce pain and inflammatory mediators. Low-power lasers can also be used instead of needles in acupuncture to decrease pain. Due to these features they have been used in the treatment of orofacial pain, including tooth hypersensitivity, post-operative flare-ups, mucositis, facial myalgia, temporomandibular joint disorders and neuralgia. In this article we review the effects of low-power lasers and their success rate in different studies. As the name implies (LASER: Light Amplification by the Stimulated Emission of Radiation), laser amplifies light by stimulated and excited radiation; in other words, it is amplification of excited light emission. Such radiation usually has some characteristic features, including mono-chromaticity, coherency, high intensity and polarity. There are various classifications for lasers based on their active material (solid, fluid and gas), wavelength, emission type and power.

Background and Aims: The present study evaluated the most common reasons for replacing amalgam restorations in a university clinic., Materials and Methods: A total of 217 restorations which needed to be replaced were clinically and radiographically evaluated in a period of 4 months. The frequencies of reasons for replacing amalgam restorations were calculated: The assessed items included recurrent caries, tooth structure fracture (functional or non-functional cusps), amalgam bulk fracture, amalgam marginal fracture, proximal overhangs, and esthetics. Data were analyzed using Fischer's exact test., Results: Both in vital teeth and teeth which had undergone root canal therapy, the most common reason for amalgam replacement was cusp fracture, with the fracture of non-functional cusps being statistically significant. Recurrent caries was the second most common reason for amalgam replacement. In Class I restorations, the most common reasons were recurrent caries and esthetics, with no statistical significance. The most frequent problem in Class II restorations was fracture of non-functional cusps, with a statistical significance in three-surface restorations., Conclusion: According to the results, failing to reduce undermined cusps and neglectful caries removal are the reasons for majority of amalgam restoration replacements. These issues should be emphasized in the curriculum for dental students and continuing education courses.

Background and Aims: The objectives of the present study were to investigate the prevalence and the position of enamel defects of primary teeth and hence to estimate the approximate time of an insult., Materials and Methods: 121 children aged 3 to 5 years were included in the study. The Modified Developmental De-fects of Enamel Index was used to diagnose and classify the defects. The defects were categorized as hypoplasia, hypocalcification or a combination of them. Each tooth was investigated for occlusal/incisal, middle, cervical, incisomiddle, cervicomiddle and complete crown defects., Results: 55.37% of the children were affected by enamel defects, 23.96% being categorized as hypocalcification and 22.31% as hypoplasia. The enamel defects were more abundant in maxillary primary incisors and mandibular primary canines. Minimum involvement was seen in maxillary primary second molars and mandibular primary lateral incisors. The prevalence of cervical defects in maxillary primary incisors was significantly more than the middle or incisal defects (P < 0.05). The prevalence of incisal defects in mandibular primary incisors was significantly more than the middle or cervical defects (P < 0.05)., Conclusion: The results revealed a considerable number of enamel defects which are multiple, symmetric and chrono-logically accordant with the estimated neonatal line in primary teeth of healthy children.

Aim: The aim of the present study was to investigate the prevalence and distribution according to various arch length conditions of lingually erupted mandibular permanent incisors and the effect of space condition on this phenomenon with long-term follow-up of these teeth., Methods and Materials: A total of 105 children aged 5-7.5 years with one or more permanent mandibular incisors erupting lingual to the corresponding primary incisors were included in the study. A space analysis was performed. The subjects were divided into six groups according to various space conditions. The subjects were followed for 2 years., Results: In this study the prevalence of lingual eruption was 18.4%. Eighty-three point seven percent of the subjects had either equivalent space, mild space excess, or a space deficiency (not more than 3 mm). No relationship was found between groups and clinical outcomes (P>.05). Follow up of the main three groups (according to the space analysis results) revealed in the adequate space group 75% of the children lost their primary incisors without any intervention. Similar outcomes occurred in 85.7% and 57.14% of cases in the mild space excess and space deficiency groups, respectively. Considering the three main groups combined, equivalent space, mild space excess, and mild space deficiency, 70.45% of children lost their primary incisors without any intervention and 14.8% needed primary incisor extraction (17.4%, 14.3%, and 10.7% in each group, respectively)., Conclusion: There was no predisposition toward a space deficiency or excess found in these subjects so the wait-and-see policy versus early extraction can be considered for lingually erupting permanent mandibular incisors., Clinical Significance: Lingual eruption of mandibular incisors is a common clinical problem in the early mixed dentition period that is a source of discomfort for parents of patients with this condition. The present study provides a unique insight into the prevalence of the problem as well as the clinical decisions such as favoring retention of primary incisors as long as possible, the extraction of these primary teeth, placement of lower lingual holding arches, or referral for comprehensive orthodontic treatment. These types of data should not be regarded as standards but as illustrative of several key factors that are still not well-understood or which are still ignored.

Background and Aims: Digital imaging continues to gain acceptance in dentistry and video display used for this becomes important. The aim of this study was to assess the influence of the display monitor on observer performance on caries detection., Materials and Methods: Artificial enamel lesions were created in 40 extracted teeth at random using 1/4 and 1/2 round burs. Teeth were mounted in dental stone blocks to simulate a hemi-dentition. Approximate exposures were recorded at 70 kVp using a Planmeca (Planmeca Co, Helsinki, Finland) digital imaging system. Three oral and maxillofacial radiologists rated each image on a five-point scale for the presence or absence of lesion. Radiographic images were viewed on the following monitors: (1) LG Flatron 700p (LG Electronics Co., South Korea); (2) Samsung Magicgreen (Samsung Electronics Corp., South Korea); (3) Hansol 710p (Hansol Electronics Corp., South Korea) and (4) Toshiba satellite laptop (Toshiba Computer Corp., Philippines). Examiners were allowed to magnify and adjust density and contrast of each image at will. Receiver Operating Characteristic (ROC) analysis was performed. Data was subjected to repeated measures analysis of variance and ordinal logistic regression to test for significance between variables and to determine odds ratios., Results: Mean ROC curve areas ranged from 0.8728 for the LG monitor to 0.8395 for the Samsung. Repeated measures analysis of variance showed significant differences between observers (P<0.0001), lesion size (P<0.0001), examiner/monitor interaction (P<0.033) and examiner/block interaction (P<0.013). However, no significant difference was found between monitors., Conclusion: This study suggests that observer performance is independent of the visual characteristics of the display monitor.

Background and Aims: Dental caries still remains a major problem in the field of oral and dental health and its prevention is more important than its treatment. Fluoride plays a significant role in prevention of caries, and improving oral and dental health. One of the common ways of fluoride use is the use of a fluoride-containing mouthwash, the most important of which in use is 0.2% sodium fluoride mouthwash. School-based fluoride mouthwash programs have been used for delivering oral and dental health to children in recent years. The aim of the present study was to assess the efficiency of 0.2% sodium fluoride mouthwash in prevention of dental caries according to DMFT index., Materials and Methods: The study included a case and a control group. For each group, 100 students were selected randomly from elementary schools of Tabriz, Iran. Case group had been participating in school-based fluoride mouthwash program for three years, while control group did not benefit from the program. The two groups were assessed by means of intra-oral examination. Data was recorded using DMFT index., Results: Following the use of 0.2% sodium fluoride mouthwash, mean DMFT index in case group decreased as much as 51.5% compared to that of control group. The mean values of decrease for the decayed, missing and filled indices were 45%, 44% and 59%, respectively. The decrease in DMFT value of the case group compared to that of control group was statistically significant (p<0.001). A statistically significant decrease was seen in the decayed and filled indices of case group (p=0.042 and p=0.016, respectively), however the missing index did not show any statistically significant difference between the two groups (p=0.361)., Conclusion: According to this study results, the weekly use of 0.2% sodium fluoride mouthwash program has been successful in elementary schools of Tabriz. Such program can play an important role in the improvement of oral and dental health among children of school age.