فهرست مطالب

Dental Research Journal
Volume:12 Issue: 2, Mar 2015

  • تاریخ انتشار: 1394/01/26
  • تعداد عناوین: 15
|
  • Saeed Moradi, Mahdi Lomee, Maryam Gharechahi* Page 109
    Background
    Apical leakage assessment is a way to compare the effi ciency of a fi lling material to seal the apical region of the tooth. Many microleakage testing techniques have been introduced through the years, but there has been no agreement as to which technique gives the most accurate results. The aim of this study was to compare the accuracy of fl uid fi ltration and bacterial leakage techniques in the assessment of the apical sealing ability of mineral trioxide aggregate (MTA) and calcium enriched mixture (CEM).
    Materials And Methods
    A sample of 34 extracted single-rooted human teeth were selected and prepared. The samples were divided in to 2 experimental groups. The apical 3 mm of each root was resected at 90° to its long axis and root end preparation was done with ultrasonic tips to a depth of 3 mm and fi lled with MTA and CEM, respectively. Assessment of apical sealing ability was done with fl uid fi ltration technique and bacterial leakage technique along 90 days with Enterococcus faecalis bacteria. Mann-Whitney U-test and Chi-square test were used to analyze the data using SPSS (SPSS Inc., Chicago, IL, USA). P less than 0.05 was considered as signifi cant.
    Results
    There was no signifi cant difference in apical sealing ability between MTA and CEM in bacterial leakage and fl uid fi ltration techniques. Samples which had bacterial leakage showed higher leakage values by fl uid fi ltration technique.
    Conclusion
    Both techniques showed same results and there was no signifi cant difference between fl uid fi ltration and bacterial leakage techniques in assessment of apical microleakage.
    Keywords: Bacterial leakage, fl uid fi ltration, microleakage, root, end fi lling
  • Gholamreza Jahanshahi*, Samaneh Shirani Page 115
    Background
    One of the probable etiologic risk factors of oral squamous cell carcinoma (OSCC) is Candidal infection, especially by Candida albicans, whose role has not defi nitely been confi rmed. Some have assigned a primary role to Candida, whereas others consider it as a transient inhabitant. The debate may be due to lack of an accurate and sensitive revealing technique. By identifying the presence of Candida, especially in deeper parts of OSCC, the etiologic role may be verifi ed. The present study was conducted to detect the presence of Candida in OSCC by fl uorescence staining technique.
    Materials And Methods
    This study was descriptive experimental. Calcofl uor white, which is applied in fl uorescence staining, is a specifi c staining substance for Candida and has a higher accuracy compared with other common methods. 100 specimens of well-differentiated OSCC with adequate amount of tissue were retrieved from the archive and two serial sections were obtained from each one. The fi rst section was stained using the popular histochemical (periodic acid-Schiff [PAS]) method and then evaluated under a light microscope to detect the presence of Candida. The second section was stained using fl uorescence staining technique. The sum of counted Candida in each technique was fed into SPSS software and analyzed by McNamara test. P < 0.001 was considered as signifi cant.
    Results
    The amount of Candida present in OSCCs was 74% measured by fl uorescence technique. The sensitivity and specifi city of the two staining techniques were signifi cantly different. These parameters in the fl uorescence technique were higher than those of the histochemical (PAS) method, confi rmed by McNamara test showing signifi cantly different results for them (P < 0.001). The results obtained from the fl uorescence technique had higher accuracy compared with the histochemical (PAS) method.
    Conclusion
    Some researchers couldn’t fi nd a considerable number of fungi in OSCC,while our results revealed more presence of Candida, especially in deeper parts of tissue samples and probably a more important role for Candida as an etiologic risk factor for OSCC. However, since the fl uorescence technique had a higher accuracy in the identifi cation of Candida and it was nearly evident in two-third of the samples, the role of fungi as a primary cause is suggested to be studied in future investigations.
    Keywords: Candida albicans, fl uorescence, oral squamous cell carcinoma
  • Angela Delfi na Bittencourt Garrido, Sueli Patricia Harumi Miyagi de Cara, Marcia Martins Marques, Emílio Carlos Sponchiado Jr., Lucas da Fonseca Roberti Garcia*, Manoel Damião de Sousa, Neto Page 121
    Background

    The constant development of new root canal sealers has allowed the solution of a large number of clinical cases in endodontics, however, cytotoxicity of such sealers must be tested before their validation as fi lling materials. The aim of this study was to evaluate the cytotoxic effect of a new Copaiba oil-based root canal sealer (Biosealer [BS]) on osteoblast-like Osteo-1 cells.

    Materials And Methods

    The experimental groups were formed according to the culture medium conditioned with the tested sealers, as follows: Control group (CG) (culture medium without conditioning); Sealer 26 (S26) - culture medium + S26; Endofi ll (EF) - culture medium + EF; AH Plus (AHP) - culture medium + AHP; and BS - culture medium + BS (Copaiba oil-based sealer). The conditioned culture medium was placed in contact with 2 × 104 cells cultivated on 60 mm diameter Petri dishes for 24 h. Then, hemocytometer count was performed to evaluate cellular viability, using Trypan Blue assay. The normal distribution of data was tested by the Kolmogorov Smirnov test and the values obtained for cellular viability were statistically analyzed (1-way ANOVA, Tukey’s test - P < 0.05), with a signifi cance level of 5%.

    Results

    S26, EF and AHP presented decreased cellular viability considerably, with statistical signifi cance compared with CG (P < 0.05). BS maintained cellular viability similar to CG (P > 0.05).

    Conclusion

    The Copaiba oil-based root canal sealer presented promising results in terms of cytotoxicity which indicated its usefulness as a root canal sealer.

    Keywords: Copaiba oil, resin, copaifera genus, cytotoxicity, natural products, root canal sealer
  • Aravind Kumar, Rampalli Viswa Chandra *, Aileni Amarender Reddy, Bavigadda Harish Reddy, Chakravarthy Reddy, Anumala Naveen Page 127
    Background
    The objective of this study was to evaluate the antiinfl ammatory, antiinfective and clinical properties of amniotic membrane (AM) when used for guided tissue regeneration (GTR) in contained interdental defects.
    Materials And Methods
    A total of 30 subjects participated in this study. Two sites in each subject were randomly assigned into each of the following experimental groups; test group: AM with bone graft and control group: Bone graft only. Clinical parameters included recording site specifi c measures of plaque, gingivitis, probing pocket depth (PPD), and clinical attachment loss (CAL). The levels of interleukin-1β (IL-1β) and human beta-defensin-2 (hBD-2) levels in gingival crevicular fl uid (GCF) from the test and control sites were measured by using commercially available enzyme linked immunosorbent assay kits. The evaluation of bone fi ll was performed by using digital subtraction technique and morphometric area analysis. One-way analysis of variance followed by the post-hoc test was used for intragroup and intergroup comparison. A P < 0.05 was considered as statistically signifi cant.
    Results
    Combination therapy using an AM increased bone fi ll and reduced PPD and CAL when compared to controls. AM also resulted in a signifi cant reduction of GCF IL-1β levels and insignifi cant increase in the hBD-2 levels.
    Conclusion
    From this trial conducted over a period of 24 weeks, AM demonstrated a marked antiinfl ammatory effect and its use resulted in an improvement in periodontal parameters. AM has the potential to function as a barrier for GTR and the unique properties associated with this material can augment its potential as a matrix for periodontal regeneration.
    Keywords: Amnion, guided periodontal tissue regeneration, periodontal bone loss, periodontitis
  • Behnaz Ebadian, Mansor Rismanchian, Badrosadat Dastgheib *, Badrosadat Dastgheib, Farshad Bajoghli Page 136
    Background
    Different factors such as impression techniques and materials can affect the passive fi t between the superstructure and implant. The aim of this study was to determine the effect of different impression materials and techniques on the dimensional accuracy of implant defi nitive casts.
    Materials And Methods
    Four internal hex implants (Biohorizons Ø4 mm) were placed on a metal maxillary model perpendicular to the horizontal plane in maxillary lateral incisors, rightcanine and left fi rst premolar areas. Three impression techniques including open tray, closed tray using ball top screw abutments and closed tray using short impression copings and two impression materials (polyether and polyvinyl siloxane) were evaluated (n = 60). The changes in distances between implant analogues in mediolateral (x) and anteroposterior (y) directions and analogue angles in x/z and y/z directions in the horizontal plane on the defi nitive casts were measured by coordinate measuring machine. The data were analyzed by multivariate two-way analysis of variance and one sample t-test (α = 0.05).
    Results
    No statistical signifi cant differences were observed between different impression techniques and materials. However, deviation and distortion of defi nitive casts had a signifi cant difference with the master model when short impression copings and polyvinyl siloxane impression material were used (P < 0.05). In open tray technique, there was a signifi cant difference in the rotation of analogs compared with the master model with both impression materials (P < 0.05).
    Conclusion
    There was no difference between open and closed tray impression techniques; however, less distortion and deviation were observed in the open tray technique. In the closed tray impression technique, ball top screw was more accurate than short impression copings.
    Keywords: Dental implants, dental impression materials, dental impression techniques, dental models
  • Ali Eskandarizadeh, Molook Torabi Parizi*, Hossein Goroohi, Hamid Badrian, Abbas Asadi, Navid Khalighinejad Page 144
    Background
    The biocompatibility of resin-modifi ed glass ionomers (RMGIs) as a lining material is still under question. The present study evaluated the response of the pulp-dentin complex following application of resin-modifi ed glass-ionomer cement, calcium hydroxide and conventional glass-ionomer in deep cavities prepared in human teeth.
    Materials And Methods
    In this controlled clinical trial, 30 deep class V buccal cavities (3 mm × 2 mm × 2 mm) were prepared in human premolars treatment planned to be extracted for orthodontic reasons and divided into 3 groups. Groups were lined by a RMGI (Vivaglass), conventional glass Ionomer (Ionocid) and calcium hydroxide respectively. The cavities were subsequently fi lled with amalgam. Each group was then divided into two sub-groups according to time intervals 5 and 30 days. The patients were referred to Kerman Dental School and in accordance with orthodontic treatment plan; premolars were extracted and then prepared for histological assessment. The sections were stained with hematoxylin and eosin and periodic acid Schiff techniques. All of the samples were examined using a number of criteria including odontoblastic changes, infl ammatory cells response, reactionary dentin formation and presence of microorganisms. The data were analyzed by Kruskal-Wallis and Mann-Whitney tests. P < 0.05 was considered as signifi cant.
    Results
    There was no signifi cant difference among odontoblastic changes, reactionary dentin, presence of bacteria and infl ammatory cells response of the groups (P > 0.05).
    Conclusion
    Ionocid and Vivaglass resin-modifi ed glass ionomers can be used as lining materials in human teeth.
    Keywords: Biocompatibility, calcium hydroxide, glass ionomer, pulp response, tertiary dentin
  • Kazem Khosravi, Seyed, Mostafa Mousavinasab, Mahsa Sahraneshin Samani* Page 150
    Background
    Despite the growing tendency toward tooth-colored restorations in dentistry, polymerization shrinkage and subsequent marginal microleakage remains a problem. The aim of this in vitro study was to compare microleakage between silorane-based and methacrylate-based composite resins at different time intervals and with different restorative techniques.
    Materials And Methods
    In this in vitro study, 108 sound extracted human molar teeth were used. Mesial and distal proximal class II boxes with dimensions of 1.5 mm depth and 4 mm width were prepared. The gingival margins of all cavities were 1 mm below the cement enamel junction. The teeth were randomly divided into three groups based on test materials. In the fi rst group, the teeth were restored by a nanocomposite (Filtek Z350XT, 3MESPE) and SE Bond adhesive (Kuraray, Japan), in the second group, the teeth were restored with a silorane-based (Filtek P90, 3MESPE) and Filtek P90 Adhesive (3M ESPE, USA) and in the third group, the teeth were restored with a microhybrid posterior composite resin (Filtek P60, 3MESPE) and SE Bond adhesive (Kuraray, Japan). Half of the proximal cavities in each of these three groups were restored in two horizontal layers and the other half in four horizontal layers. After a period of aging (24-h, 3-month and 6-month) in water and then application of 500 thermal cycles, the teeth were immersed for 24-h in 0.5% fuchsin and evaluated under a stereomicroscope at ×36 magnifi cation to evaluate leakage in gingival margin. Data was statistically analyzed using Kruskal-Wallis and Mann-Whitney U-tests. P ≤ 0.05 was considered as signifi cant.
    Results
    In Z350XT statistically signifi cant differences were observed in microleakage in comparison of 24-h and 6-month intervals (P = 0.01) that was higher in 6-month. Comparison of microleakage in P90 and P60 composite resins was also statistically signifi cant and was less in P90. Microleakage was not signifi cantly different between P90 and Z350XT at 24-h. However, this difference was signifi cant at 3-month and 6-month intervals. Differences in microleakage of P60 and Z-350XT composite resins were not statistically signifi cant in all intervals (P = 0.38). P90 showed the lowest microleakage during storage in water. Z350XT had microleakage similar to P90 within 24-h, but after 6-month of storage in water, it showed the highest microleakage among all the groups. The number of layers (2 layers vs. 4 layers) did not result in any differences in microleakage scores of the composite resins (P = 0.42).
    Conclusion
    Water storage times did not result in any signifi cant effect on microleakage of P90 and P60.
    Keywords: Methacrylate, based composite, microleakage, silorane, based composite, storage
  • Abbass Ali Khademi, Kamal Amini, Behnaz Ghodsian, Sharare Mousavi Zahed, Faraz Teymori, Elham Shadmehr Page 157
  • Shoaleh Shahidi, Nahal Kazerooni Zadeh, Farahnaz Sharafeddin, Shahriar Shahab, Ehsan Bahrampour, Shahram Hamedani* Page 161
    Background
    This study was aimed to compare the diagnostic accuracy and feasibility of cone beam computed tomography (CBCT) with phosphor storage plate (PSP) in detection of simulated occlusal secondary caries.
    Materials And Methods
    In this in vitro descriptive-comparative study, a total of 80 slots ofclass I cavities were prepared on 80 extracted human premolars. Then, 40 teeth were randomly selected out of this sample and artifi cial carious lesions were created on these teeth by a round diamond bur no. 1/2. All 80 teeth were restored with amalgam fi llings and radiographs were taken, both with PSP system and CBCT. All images were evaluated by three calibrated observers. The area under the receiver operating characteristic curve was used to compare the diagnostic accuracy of two systems. SPSS (SPSS Inc., Chicago, IL, USA) was adopted for statistical analysis. The difference between Az value of bitewing and CBCT methods were compared by pairwise comparison method. The inter- and intra-operator agreement was assessed by kappa analysis (P < 0.05).
    Results
    The mean Az value for bitewings and CBCT was 0.903 and 0.994, respectively. Signifi cant differences were found between PSP and CBCT (P = 0.010). The kappa value for inter observer agreement was 0.68 and 0.76 for PSP and CBCT, respectively. The kappa value for intra observer agreement was 0.698 (observer 1, P = 0.000), 0.766 (observer 2, P = 0.000) and 0.71 (observer 3, P = 0.000) in PSP method, and 0.816 (observer 1, P = 0.000), 0.653 (observer 2, P = 0.000) and 0.744 (observer 3, P = 0.000) in CBCT method.
    Conclusion
    This in vitro study, with a limited number of samples, showed that the New Tom VGI Flex CBCT system was more accurate than the PSP in detecting the simulated small secondary occlusal caries under amalgam restoration.
    Keywords: Cone, beam computed tomography, dental caries, dental radiograph, digital radiograph
  • Niloofar Shadman, Shahram Farzin Ebrahimi *, Maryam Azizi Shoul, Hasti Sattari Page 167
    Background
    Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) is applied for remineralization of early caries lesions or tooth sensitivity conditions and may affect subsequent resin bonding. This in vitro study investigated the effect of CPP-ACP on the shear bond strength of dental adhesives to enamel.
    Materials And Methods
    Sixty extracted human molar teeth were selected and randomly divided into three groups and six subgroups. Buccal or lingual surfaces of teeth were prepared to create a fl at enamel surface. Adhesives used were Tetric N-Bond, AdheSE and AdheSE One F. In three subgroups, before applying adhesives, enamel surfaces were treated with Tooth Mousse CPP-ACP for one hour, rinsed and stored in 37°C temperature with 100% humidity. This procedure was repeated for 5 days and then adhesives were applied and Tetric N-Ceram composite was adhered to the enamel. This procedure was also fulfi lled for the other three subgroups without CPP-ACP treatment. After 24 hour water storage, samples were tested for shear bond strength test in a universal testing machine. Failure modes were determined by stereomicroscope. Data were analyzed by t-test and one-way analysis of variance with P < 0.05 as the level of signifi cance.
    Results
    In comparison between applied and non-applied CPP-ACP subgroups, there was no signifi cant decrease in the shear bond strength to enamel only in Tetric N-Bond (P > 0.05). In nonapplied CPP-ACP subgroups, there were statistically signifi cant differences among all subgroups. Tetric N-Bond had the highest and AdheSE One F had the lowest shear bond strength.
    Conclusion
    CPP-ACP application reduces the shear bond strength of AdheSE and AdheSE One F to enamel but not Tetric N-Bond.
    Keywords: Casein phosphopeptide, amorphous calcium phosphate, enamel, etch, rinse, self, etch, shear bond strength
  • Najmeh Khatoon Khaksaran, Tahereh Jafarzadeh Kashi, Vahid Rakhshan, Zahra Sadat Zeynolabedin, Hossein Bagheri* Page 173
    Background
    Application of bonding agents (BA) into deep cavities and light curing them might increase pulpal temperature and threaten its health. The purpose of this study was to evaluate temperature rise of pulp by light curing six BA using two different light curing units (LCU), through a dent in wall of 0.5 mm.
    Materials And Methods
    This in vitro experiment was carried out on 96 slices of the samenumber of human third molars (6 BAs × 2 LCUs × 8 specimens in each group). There were 6 groups of BAs: N Bond, G-Bond, OptiBond XTR, Clearfi l SE, Adper Single Bond 2 and V Bond. Each group of BA (n = 16) had two subgroups of light emitting diode (LED) and quartz tungstenhalogen light cure units (n = 8). Each of these 16 specimens were subjected to light emitting for 20 s, once without any BAs (control) and later when a BA was applied to surface of disk. Temperature rises in 140 s were evaluated. Their mean temperature change in fi rst 20 s were calculated and analyzed using two-way repeated-measures and one-way analysis of variance (ANOVA) and Tukey (α = 0.05). Furthermore rate of temperature increase was calculated for each material and LCU.
    Results
    Minimum and maximum temperature rises in all subgroups were 1.7 and 2.8°C, respectively. Repeated measures ANOVA showed that both of adhesive and LCU types had signifi cant effect on temperature rise after application of adhesives. Tukey post-hoc analysis showed Clearfi l SE showed signifi cantly higher temperature rise in comparison with Adper Single bond 2 (P = 0.047) and N Bond (P = 0.038). Temperature rose in a linear fashion during fi rst 30 40 s and after that it was non-linear.
    Conclusion
    20 s of light curing seems safe for pulpal health (with critical threshold of 5.5 C). However, in longer durations and especially when using LED units, the process should be broken to two sessions.
    Keywords: Composite resins, dental materials, differential thermal analysis, polymerization
  • Pouyan Amini Shakib*, Fereshteh Ensani, Afshin Abdirad, Bahareh Valizadeh, Maryam Seyedmajidi, Shima Sum Page 181
    Background
    Considering molecular target therapy concept in the treatment of oral squamous cell carcinoma (OSCC), many attempts have been performed to introduce an effective molecular marker during recent years. Several investigations have emphasized on the role of CD44 in variouscancers and few studies have mentioned CD24 and CD74. The purpose of this study was to investigate the relationship between CD44, CD24 and CD74 expressions and several clinical or histopathological factors in OSCC patients.
    Materials And Methods
    In our analytical cross-sectional study, forty primary OSCC specimens were immunohistochemically stained for CD44, CD24, and CD74 proteins. Then, the relationship between their expressions and age, sex, lymph node metastasis, and histopathologic grading was statistically analyzed using Mann-Whitney nonparametric and t-test. Furthermore, P < 0. was considered as signifi cant.
    Results
    CD44 and CD74 proteins were signifi cantly over-expressed in OSCC patients with high grade (P = 0.001 and P = 0.001) as compared to those with low grade. Furthermore, CD74 immunoreactivity showed signifi cantly higher expression in patients with lower age (P = 0.039). Considering lymph node metastasis, we observed signifi cant overexpression of CD74 in patients with no lymph node involvement (P = 0.033).
    Conclusion
    Our observations support the signifi cant role of membranous CD44 protein in progression of OSCC and also introduce CD74 protein as a probable interfering factor in different aspects of OSCC.
    Keywords: Antigen, CD24, CD44, carcinoma, immunohistochemistry, squamous cell of head, neck
  • Elham Shadmehr, Sima Kiaani, Parinaz Mahdavian* Page 187
    Dens invaginatus is a rare developmental anomaly of teeth with complex root canal system morphology. The present case describes a peg shape maxillary lateral incisor with dens invaginatus (Oehlers type II), necrotic pulp, and an associated large periradicular lesion. Nonsurgical endodontic treatment was performed with the aim of removing the blind sac with diamond bur under the use of operating surgical microscope. The root canal system was obturated with thermoplastic technique. Final restoration was done using composite. The 20-months clinical and radiological follow up revealed an asymptomatic tooth with healing of the periapical pathology; however, for complete healed periradicular lesion more follow up is needed. This case illustrated that a dens invaginatus malformed teeth with a large periradicular lesion can be managed successfully with nonsurgical root canal therapy (NSRCT).
    Keywords: Case report, dens invaginatus type II, lateral incisor, nonsurgical endodontic treatment, nonsurgical root canal therapy, periradicular lesion
  • Elham Shadmehr, Neda Shekarchizade* Page 192
    Paresthesia is a burning or prickling sensation or partial numbness, resulting from neural injury. The symptoms can vary from mild neurosensory dysfunction to total loss of sensation in the innervated area. Only a few cases have described apical periodontitis to be the etiological factor of impaired sensation in the area innervated by the inferior alveolar and mental nerves. The aim of the present paper is to report a case of periapical lesion-induced paresthesia in the innervation area of the mental nerve, which was successfully treated with endodontic retreatment.
    Keywords: Apical periodontitis, endodontic therapy, inferior alveolar nerve, paresthesia
  • Mahmood Reza Kalantar Motamedi*, Zahra Golestannejad Page 197