Vol 10, No 4 (2013)
Proceeding Abstracts
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To assess the effects of different final irrigants on the bond strength of bonded root filling materials, Epiphany/Resilon and Epiphany self-etch (SE)/Resilon.The root canals of eighty single-rooted extracted human teeth were prepared. After the smear layer was removed using 17% EDTA, the samples were randomly divided into eight groups. In groups 1 and 2, no additional irrigant was used after EDTA. In the other groups, final irrigation was performed with 2.5% NaOCl (groups 3 and 4), 2% chlorhexidine (CHX) (groups 5 and 6), and normal saline (groups 7 and 8). The root canals were obturated with Epiphany/Resilon in groups 1, 3, 5 and 7 and obturated with Epiphany SE/Resilon in groups 2, 4, 6 and 8. After the middle thirds of the roots were horizontally sectioned, the push-out bond strength of root filling materials was assessed using the universal testing machine. The data were analyzed using Mann-Whitney and Kruskal-Wallis tests. The significance level was set at p<0.05.There was no significant difference between the push-out bond strength of Epiphany/Resilon and Epiphany SE/Resilon (p>0.05). Considering the irrigation protocols, final irrigation with 2.5% NaOCl was associated with a significantly lower bond strength of both filling materials than the other irrigants (p<0.05). EDTA, CHX and normal saline had similar effects on the bond strengths of filling materials (p>0.05).Final irrigation of the root canals with 2.5% NaOCl following application of EDTA had a negative effect on the bond strength of Epiphany and Epiphany SE obturation systems.
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Inhibition of prostaglandin (PGs) production leads to decrease in orthodontic tooth movement (OTM). It is not known whether inhibition of cyclooxygenase-1 (COX-1) or cyclooxygenase-2 (COX-2) is the key mechanism for this effect. In this study, the effect of celecoxib, a highly-selective COX-2 inhibitor, was investigated on OTM in rats.Four groups of male rats (seven animals in each goup) were used in the study. A 5mm-long nickel-titanium closed-coil spring was ligated between the right maxillary incisor and the first molar of each rat to deliver an initial force of 60g. All four groups recieved orthodontic appliances, group 1 received no injections, group 2 received celecoxib injections (0.3 mg in 0.1 ml saline solution), group 3 recieved normal saline injections (0.1 ml saline solution), and group 4 recieved needle penetration without injecting any solution. The local injections were carried out every 3 days for 18 days. All injections were subperiosteal and given in the upper right first molar mucosa. The animals were sacrificed 21 days after appliance insertion and OTM was measured.In the animals treated with celecoxib a statistically significant decrease in OTM was observed compared with the other groups. Histological findings revealed that osteoclast count was significantly lower in group 2 compared with the other groups (P<0.05). The amount of root resorption showed a slight, but nonsignificant decrease in group 3.This study suggests that celecoxib decreases OTM and osteoclast count. This might be the result of COX-2 enzyme inhibition and subsequent decrease in prostaglandin production.
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Association of IL-8 (-251 a/t) gene polymorphism with clinical parameters and chronic periodontitis.To investigate the correlation between IL-8 (-251 A/T) gene polymorphism and susceptibility to chronic periodontitis as well as different clinical parameters and severity of the condition in patients referred to dental school, Shiraz University of Medical Sciences, Shiraz, Iran.In this randomized cross sectional study, 227 non-smoking patients with chronic periodontitis (test) and 40 healthy individuals (control) were enrolled in this experiment and the following clinical parameters were employed in the study: Periodontal Pocket Depth (PPD), Clinical Attachment Level (CAL) and Bone Loss (BL). All participants underwent the PCR (Polymerase Chain Reaction) test to detect 251 A/T Single Nucleotide Polymorphism of IL8 gene.No significant correlation was perceived between different genotypes of IL-8 and the severity of the periodontal condition (P= 0.164), neither did we detect any substantial association between different IL-8 genotypes and the mean PPD (P=0.525), CAL (P=0.151), BL (P=0.255), PI (P=0.087), BOP (P=0.265) and the average number of teeth (P=0.931).The results implied that there was no explicit correlation between 251 (A/T) IL-8 gene polymorphism and the severity of the chronic periodontal disease or to the susceptibility to it.
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To retrospectively evaluate the treated cases with odontogenic abscess and identify the outcome of odontogenic infections, their characteristics and treatment modalities.This retrospective study was performed by collecting data from 310 patient records at the oral and maxillofacial surgery department of Taleghani hospital, Tehran, Iran from January 2001 to January 2011. The variables were age, gender, affected teeth, affected facial spaces, type of bacterial source, type of antibiotic therapy, previous medication, hospital stay, body temperature on admission and past medical history.The patients' ages were between 2 and 84 years and 62.6% of the patients with odontogenic infection were younger than 35 years old. Most of the patients had a body temperature of 37-37.5°C. The most involved teeth were mandibular third molar. Deciduous teeth contained 6.4% of the involved teeth, among which mandibular molars were the most involved. 24.3% of the patients were hospitalized for 4 days. Streptococci were the most detected bacterial strain. The most involved anatomic space was the buccal space and 22.5% of the cases had multi space involvement and 17 cases had Ludwig's angina. The most common used antibiotic regimens were penicillin G and metronidazole or cefazolin and metronidazole. The mortality rate was 1%, all of whom had Ludwig's angina.The main affected facial spaces were buccal and submandibular spaces. The most common used antibiotic was penicillin, proving its effectiveness in the treatment of jaw infections. Odontogenic abscesses are mostly related to the eruption of mandibular molars.
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Over the past two decades, there has been a growing trend in using oral hygienic products from natural resources such as essential oils and plant extracts. Nepeta cataria L. is a member of the mint family (Labiatae) with several medicinal properties. The objective of this study was to determine the chemical composition and antimicrobial activities of essential oils (EOs) from N. cataria leaves against pathogens causing oral infections.The chemical composition of EOs from N. cataria was analyzed by gas chromatography/mass spectrometry (GC/MS). The antimicrobial activity of the essential oil was evaluated by broth micro-dilution in 96 well plates as recommended by the Clinical and Laboratory Standards Institute (CLSI) methods. The plates were incubated at 30°C for 24-48 h (fungi) or at 37°C for 24 h (bacteria).The analysis of the EOs indicated that 4a-α, 7-α, 7a-β-nepetalactone (55-58%), and 4a-α, 7-β, 7a-α-nepetalactone (30-31.2%) were the major compounds of the EOs at all developmental stages. The tested EOs exhibited antimicrobial activities against the tested bacteria at concentrations of 0.125-4 μL/mL. Moreover, the oils entirely inhibited the growth of Candida species at a concentration less than 1 μL/mL.Based on these results, the EO of N. cataria can possibly be used as an antimicrobial agent in the treatment and control of oral pathogens.
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The purpose of this study was to determine the influence of platform switching on stress distribution of two different implant systems using three-dimensional (3D) finite element models.Six 3D finite element models were created to replicate two different implant systems with peri-implant bone tissue, in which six different implant-abutment configurations were represented: model XiVE-a: 3.8-mm-diameter implant and 3.8-mm-diameter abutment; model XiVE-b (platform-switching model): 4.5-mm-diameter implant and 3.8-mm-diameter abutment; model XiVE-c: 4.5-mm-diameter implant and 4.5-mm-diameter abutment; model 3i-a: 4.0-mm-diameter implant and 4.1-mm-diameter abutment; model 3i-b (platform-switching model): 5.0-mm-diameter implant and 4.1-mm-diameter abutment; model 3i-c: 5.0-mm-diameter implant and 5.0-mm-diameter abutment. vertical and oblique loads of 100 were applied to all models.While the pattern of stress distribution was similar for both loading situations, oblique loading resulted in higher intensity and greater distribution of stress than axial loading in both cortical bone and implant-abutment- interface. Stress distribution at peri-implant bone was almost identical with similar magnitudes for all six models. In both implant systems, platform-switching models demonstrated lower maximum von Mises stress in cortical bone than conventional models. However, in both implant systems and under both loading situations, platform-switching models showed higher stresses at the implant-abutment interface than conventional models.In both implant systems, platform switching design reduced the stress concentration in the crestal bone and shifted it towards the area of implant-abutment interface.
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The aim of this randomized controlled clinical trial was to investigate the effect of a new Iranian toothpaste and a commercially available toothpaste containing desensitizing agent (5% potassium nitrate) on dentine hypersensitivity in a 24-week study.Fifty healthy volunteers, who had at least two sensitive root surfaces, completed the study period. The participants were randomly given one of the two toothpastes; Iranian (antihypersensitive Pooneh) or commercially available (fresh mint Sensodyne) toothpaste. Visual analogue scales (VASs) indicating the intensity of tooth hypersensitivity responding to tactile, airblast and cold-water stimuli were examined at baseline and weeks 2, 4, 12 and 24.Overall, VAS scores for tactile, airblast, and cold-water tests significantly reduced compared with the baseline in both groups (all P values <0.001). However, there was no significant difference between the two groups regarding the measured parameters.This study demonstrated that the Iranian dentifrice (antihypersensitive Pooneh) was as effective as the commercially available one (fresh mint Sensodyne) in reducing tooth hypersensitivity.
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To evaluate differences in the root and canal configurations of mandibular permanent anterior incisors and canines in an Iranian population by means of Cone Beam CT (CBCT) images.Four hundred CBCT images of mandibular permanent incisors and canines that met the inclusion criteria were evaluated. Vertucci's classification was used to evaluate the number of roots, number of root canals, root lengths, root curvatures and canal types.Totally 632 central incisors, 614 lateral incisors and 608 canines were evaluated. The average length of the mandibular central, lateral incisors and canines was 21.3±0.10, 21.9± 0.13 and 25.1± 0.11 mm, respectively. All of the mandibular central and lateral incisors had one root, but the incidence of single-rooted mandibular canines and two-rooted mandibular canines was 96.3% and 4.7%, respectively. The majority of mandibular central, lateral incisors and canines had one canal (72.7%, 70.6% and 71.8%, respectively). Five types of Vertucci canal configurations were seen in the evaluated teeth. Type 1 Vertucci configuration was the most prevalent configuration (72.3%, 70.6% and 71.8% for the central, lateral incisors and canines, respectively)), and type 5 Vertucci canal configuration was the least prevalent type seen (3.3%, 3.2% and 2.3% for the central, lateral incisors and canines, respectively). The most frequent root curvatures in these teeth were distally and buccally. No significant difference was seen between male and female patients regarding any of the parameters evaluated in this study (p>0.05).More attention should be given to the detection of additional canals and the recognition of canal curvature in Iranian patients.
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Eradication of microorganisms present in the root canal system is paramount for the successful outcome of root canal therapy. The purpose of this study was to compare the of doxycycline absorbed from MTAD into root canal dentin after obturation with gutta-percha/AH26 and Resilon/RealSeal at different time intervals.Fifty-one extracted human teeth were instrumented. Thirty samples were obturated with either gutta-percha/AH26 or Resilon/self-etch RealSeal after final irrigation with MTAD. Fifteen samples were kept unobturated (positive control); six samples were obturated with either gutta-percha/AH26 or Resilon/self-etch RealSeal without MTAD irrigation (negative control). After aging for 1, 3 or 6 weeks, dentin debri were collected, the Doxycycline compound was extracted and its amount was quantified using high performance liquid chromatography. The statistical significance of the change in Doxycycline concentrations was tested with two-way ANOVA.The mean concentration of Doxycycline in dentin for one, three and six-week guttapercha/AH26 samples was 1.8±0.36, 1.22±0.22 and 0.67±0.11 respectively, whereas these concentrations in Resilon/RealSeal samples were 1.60±0.26, 0.80±0.14 and 0.59±0.01 respectively. Regarding the positive control group, these concentrations were 2.09±0.11, 1.54±0.12 and 0.72±0.07 respectively for 1, 3 and 6-week intervals. No Doxycycline was detected in negative control groups. The Doxycycline concentrations showed a significant difference forobturating materials (p=0.008). These concentrations were higher in the gutta-percha/AH26 samples than Resilon/RealSeal samples in each time interval.The remaining amount of Doxycycline bonded to dentin was higher when root canals were obturated with gutta-percha/AH26 compared to Resilon/RealSeal. The stability of Doxycycline showed a time dependent decrease.
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Calcium fluoride deposit during fluoride application. Uptake and retention of fluoride by saliva depends generally on the concentration of calcium. In this study, the effect of calcium pre-rinse on salivary fluoride concentration after a 900 ppm fluoride mouthwash was investigated.This cross-over double-blind randomized clinical trial was conducted in a girls' dormitory in Zahedan University of Medical Sciences, southeast Iran. In this study, 42 female dental students were chosen using simple randomization. During the first phase, 21 subjects (group A) used fluoride rinse (F regimen) and the remaining (group B) used calcium pre-rinse followed immediately by fluoride rinse (Ca + F regimen). In the second phase, participants rinsed using the mouthwashes not previously used. Prior to each phase prophylaxis was performed and no fluoridated product was used during a two-week interval between the phases. Salivary samples were taken immediately before (baseline), 1 and 12 hours after rinsing. The salivary fluoride concentration was determined using fluoride sensitive electrode. Repeated measures ANOVA was used for statistical analysis and the significance level was set at P<0.05.There was significant difference between fluoride concentrations at different time points (P< 0.001). Significant differences were observed when the different time points of two regimens were examined. In contrast to this, the baseline before using F regimen and the baseline before using Ca + F regimen did not show any significance (P= 0.070).Pre-rinsing with calcium before fluoride is recommended because of significant increases in salivary fluoride concentration.
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The presence of supernumerary teeth is not uncommon in the general population. They occur more frequently in patients with a family history of such teeth. It is rare to find multiple supernumeraries in individuals with no other associated disease or syndrome. There have been very few documented cases of bilateral maxillary and mandibular supernumeraries in the premolar region. An unusual case of a 35-year-old man with six para premolars and complete dentition is presented.
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Pre-implant disease is an inflammatory process that affects the surrounding tissues of a functional osseointegrated implant. It is usually the result of a disequilibrium between the micro-flora and the defense system. This case reports a 57-year-old man with unusual bone loss around dental implants. This was an unusual case of peri-implantitis that occurred only in the implants on one side of the mouth although they were all unloaded implants.
