JOURNAL OF DENTISTRY (SHIRAZ UNIVERSITY OF MEDICAL SCIENCES)
Year:2016 | Volume:17 | Issue:3|Papers Count:8

Statement of the Problem: Composite bond to dentin is crucial in many clinical conditions particularly in deep cavities without enamel margins due to insufficient penetration of adhesive into demineralized dentin.Purpose: The aim of this study was to assess the shear bond strength (SBS) of a methacrylate- based and a silorane-based composite resin to surface and deep dentin after pretreatment with dimethyl sulfoxide (DMSO).Materials and Method: Eighty extracted human premolars were randomly divided into two groups of flat occlusal dentin with different cuts as A: surface group (sections just below the dentinoenamel junction (DEJ) and B: deep group (2 mm below DEJ).Each group was randomly assigned to 4 subgroups and their samples were restored with Adper Single bond (ASB) and Filtek Z350 or Silorane system Adhesive (SA) and Filtek P90 composite resins, using a 3×3mm cylindrical plastic mold. following these steps, the subgroups were assigned as SubgroupA1: surface dentin+Silorane System Primer (SSP)+Silorane System Bonding (SSB)+P90; Subgroup A2: surface dentin+37% etchant (E37%) +Adper Single Bond (ASB)+Z350; Subgroup A3: surface dentin+ DMSO+SSP+SSB+P90; Subgroup A4: surface dentin+E37%+DMSO+ASB+ Z350; Subgroup B1: deep dentin+SSP+SSB+P90; Subgroup B2: deep dentin+ E37%+ASB+Z350; Subgroup B3: deep dentin+DMSO+SSP+SSB+P90; Subgroup B4: dentin+E37%+DMSO+ASB+Z350. The specimens were thermocycled at 5±2.55±2oC for 1000 cycles and then tested for SBS.Results: Using DMSO as dentin conditioner increased SBS of ASB to deep dentin (p< 0.001) and SBS of SA to surface dentin (p=0.003) but had no effect on SBS of SA to deep dentin (p=1.00).Conclusion: The ability of DMSO to increase SBS of ASB to deep dentin provides a basis for improving bonding of this composite resin in deep cavities.

Statement of the Problem: Oral lichen planus (OLP) is a chronic inflammatory disorder with various clinical features; however, its pathogenesis is still unknown.In OLP, destruction of the basement membrane and migration of T-cell may be mediated by matrix metalloproteinases.Purpose: The aim of this study was to examine the role of stromelysin-2 (ST-2) expression in pathogenesis of OLP.Materials and Method: A retrospective analysis of 46 samples including 26 patients with OLP and 20 control patients with oral irritation fibroma was performed.All samples were stained employing immunohistochemistry method. After immunohistochemical staining for ST-2 marker and microscopic examination of the samples, the expression levels of ST-2 were evaluated. The data were analyzed by SPSS (V.21) and applying Mann-Whitney test.Results: The strength of ST-2 expression was seen in most cases of OLP group, whereas control group did not show ST-2 expression. Mean expression of ST-2 in connective tissue was 1.7±1.10 and in the epithelium of the OLP samples was 1.6±1.06. Likewise, the ST-2 expression in connective tissue and epithelium of the OLP erosive lesions was significantly higher in comparison with reticular lesions (p<0.05).Conclusion: According to the results of this study, we suggest that ST-2 may be involved in the formation of OLP lesions and it may play a key role in the transformation of reticular to erosive form of OLP.

Statement of the Problem: Phenytoin (PHT) has been known to promote wound healing in some medical conditions owing to its proliferative as well as antiinflammatory effects. Yet, its application in oral lesions was less investigated.Purpose: The aim of this study was to evaluate changes in periodontal indices following the topical use of phenytoin in chronic periodontitis.Materials and Method: In this doubled-blind, randomized, split-mouth controlled clinical study, 20 patients with moderate to severe chronic periodontitis referred to Periodontology Department of Shahid Sadoughi Medical University of Yazd in 2014 were selected consecutively. After initial therapy (scaling and root planning and oral hygiene instructions), periodontal indices including bleeding on probing (BOP), periodontal pocket depth (PPD) and modified gingival index (MGI) were recorded. Gingival facial surface of two posterior sextants with at least two teeth with similar conditions, were selected randomly. Then one surface received PHT paste whereas the other side had placebo as control. Patients were received the mucoadhesive pastes under strict control by an examiner, twice a day for a week. Periodontal indices were measured 3 weeks after treatment. Data was analyzed with t-test and paired t-test by using SPSS 21 software.Results: It was observed that periodontal pocket depth was significantly more decreased in phenytoin side in comparison with placebo one (p<0.05). In addition, inflammatory indices including bleeding on probing and modified gingival index declined more in the phenytoin group (p=0.001 and p<0.05 respectively).Conclusion: These encouraging results support the use of 1% phenytoin mucoadhesive paste as an adjunctive in periodontal treatment.

Statement of the Problem: Stainless steel brackets release metallic ions following the process of corrosion in the oral environment. These released ions have potential adverse effects on health, friction between wire and bracket, staining, strength of brackets.Choosing a bracket with favorable corrosive properties; therefore, should be a goal of every practitioner.Purpose: The goal of this study is to compare the amount of corrosion among five different brands of brackets using inductively coupled plasma (ICP) mass spectrometry.Materials and Method: Five different brands of brackets (Dentaurum, 3M, Ortho Organizer, Cobas and O.R.G) were chosen and ten brackets were selected from each brand. A piece of stainless steel wire was ligated to each bracket. The bracket-archwire complex was then immersed in artificial saliva. Subsequently, the samples were analyzed using an ICP device and the levels of iron, chromium, nickel, and manganese ions were measured.Results: The findings of this study demonstrated that iron was released the most from the tested brackets, followed by nickel. We also found that the Cobas bracket had the most ion release among the tested brackets (p<0.05), while Ortho Organizer and ORG performed favorably. There was no significant difference between Dentaurum and 3M (p>0.05).Conclusion: Based on the results, Ortho Organizer and ORG brackets are suggested in terms of resistance to corrosion.

Statement of the Problem: Individuals with cleft lip and cleft palate mostly have airway problems. Introduction of cone beam computed tomography (CBCT) and imaging software has provided the opportunity for a more precisely evaluating 3D volume of the airway.Purpose: The purpose of this study was to analyze and compare 3D the pharyngeal airway volumes of cleft palate patients with normal individuals using CBCT.Materials and Method: 30 complete cleft palate patients were selected from the Department of Orthodontics; Dental University (Shiraz, Iran) who had CBCT scans of the head. The control group included 30 individuals with Class I angle occlusion who were matched for age and gender with the experimental group. ITK-SNAP 2.4.0 PC software was used to build 3D models of the airways for the subjects and measuring airway volumes. The statistical analyses were performed using SPSS software (version 19). Mann-Whitney test was adopted with p<0.05 as statistical significance.Results: The average volume of the pharyngeal airway of cleft group was 18.6 cm3, with mean volumes of 6.8 cm3 for the superior component and 11.3 cm3 for the inferior component. The total and superior airway volume of cleft group were significantly lower than non-cleft groups (p=0.008, p=0.00, respectively) but the inferior airway volumes were not significantly different between the cleft and non-cleft groups. There was a significant and positive correlation between superior airway volume and inferior airway volume in cleft palate patients (r=+0.786, p<0.001) and control group (r=+0.575, p=0.001).Conclusion: 3D analysis showed that the nasal and total airway was restricted in individuals with cleft palate but the inferior airway was not compromised in these individuals. This would be a crucial data to be considered for surgeons during surgical planning.

Statement of the Problem: The preoperative or intraoperative administration of intravenous magnesium sulfate has been approved as an accepted medication for stabilizing hemodynamic indices during surgeries.Purpose: Intraoperative blood loss during orthognathic surgery is frequently abundant and sometimes requires blood transfusion. The present trial addressed the efficacy of intravenous magnesium sulfate on deliberating hypotension and bleeding reduction in patients undergoing bimaxillary orthognathic surgery.Materials and Method: This randomized double-blinded placebo controlled trial was conducted on 52 consecutive patients who underwent orthognathic surgery. The participants were randomly assigned to two groups receiving intravenous magnesium sulfate 30 mg/kg body weight bolus for 15 minutes immediately before anesthesia induction, followed by 10 mg/kg/hr dissolved in saline via pump infusion (n=26) and the second group received placebo as same bolus volume of normal saline in a 15-minute intravenous infusion which was continued until the end of operation (n=26). Both systolic and diastolic blood pressures were measured before anesthesia induction at baseline, during surgery, and at the end of the surgery.Intraoperative blood loss was also determined.Results: Systolic and diastolic blood pressures did not differ between the two groups at baseline. Although a downward trend of both systolic and diastolic blood pressures was seen during the operation in both groups, the decrease in blood pressures occurred with greater gradient in the group administered magnesium sulfate. Assessing difference in the trend of the changes in systolic and diastolic blood pressures between the two study groups (adjusted for gender, age, mean body mass index, and time of surgery) showed different trends in the changes of blood pressures. No differences were observed in blood loss or blood product requirement between the two groups.Conclusion: The administration of intravenous magnesium sulfate can attenuate both systolic and diastolic blood pressures during orthognathic surgery with no significant effect on the volume of blood loss or need for blood transfusion.

Statement of the Problem: Denture stomatitis is the common form of oral candidiasis, which is seen in the form of diffused inflammation in the areas covered by dentures. Many primary studies report the prevalence of denture stomatitis and candida albicans among patients in the Iranian population; therefore, using meta-analysis is valuable for health policy makers.Purpose: The purpose of the present study is to determine the prevalence of denture stomatitis and candida albicans in Iran.Materials and Method: Using relevant keywords, national and international databases were searched. After limiting the search strategy and deleting the duplicates, the remaining papers were screened by examining the title and abstract. In order to increase the sensitivity of search reference lists of papers were examined. Finally the index of heterogeneity between studies was defined using Cochran test (Q) and Isquared (I2). According to heterogeneity, the random effects model was used to estimate the prevalence of denture stomatitis and candida albicans in Iran.Result: The prevalence of denture stomatitis in 12 studies, and the prevalence of candida albicans in patients with denture stomatitis have been reported in 6 studies. The number of sample under investigated and its age range among primary studies included meta- analysis was 2271 individuals and 32.7 till 87.5 years respectively. The prevalence of denture stomatitis in preliminary studies imported to a meta-analysis varied from 1.9% to 54.6%, and its rate in Iran using the meta-analysis was estimated 28.9 % (CI 95%: 18.2-39.6). Also the overall prevalence of candida albicans in patients with denture stomatitis in Iran was estimated 60.6% (CI 95%: 50.1-71.2).Conclusion: This study showed that the prevalence of denture stomatitis and candida albicans among patient infected denture stomatitis is relatively significant in Iran.

In oral cavity neurogenic tumors are rare, especially if they are malignant. Neurofibromas are the benign tumors of nerve sheath origin involving multiple nerve fascicles of the smaller branches of peripheral nerves. They may present as solitary lesions or as a part of generalized syndrome of neurofibromatosis also known as von Recklinghausen’s disease (VRD) or very rarely as multiple neurofibromas without VRD. Oral solitary neurofibromas are not uncommon, but histologically plexiform variant is a rare form. This article describes a case of oral solitary plexiform neurofibroma with a review of literature.