فهرست مطالب

Dental Research Journal
Volume:18 Issue: 5, Jun 2021

  • تاریخ انتشار: 1400/06/19
  • تعداد عناوین: 11
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  • Amin Khaleghi, Atefe Ahmadvand, Saeid Sadeghian Page 1
    Background

    This study aimed to assess the effect of citric acid, as a weak acid commonly used in food industry, on elastomeric chain force decay.

    Materials and Methods

    In this in vitro, experimental study, sixty elastomeric chains from two commercial brands of American Orthodontics and Ortho Technology (n = 30) were cut into five‑piece segments.Elastomeric chains of each brand were randomly divided into two groups of control (artificial saliva) and citric acid.All elastomeric chains were incubated in artificial saliva at 37°C. Experimental samples were immersed in 10 mL of citric acid for 90 s daily and were then transferred back to the artificial saliva.The elastomeric chain force was measured at baseline (before the experiment), 1 day, 1 week,2 weeks,and 3 weeks using an electromechanical universal testing machine.Data were analyzed using t‑test,Kruskal–Wallis test, and Mann–Whitney U‑test at 0.05 level of significance.

    Results

    The elastomeric chain force gradually degraded overtime.The difference in thisrespect was not significant at 2 and 3 weeks in any group (P > 0.05). On initiation of the experiment,the force in the citric acid group experienced a greater decay than that in the control group; the difference between the citric acid and control groups in both the brands was significant at all time points until the end of the 3rd week (P < 0.05).The difference between theAmerican Orthodontics and Ortho Technology brands in the control and citric acid groups was significant at all time points (P < 0.001).

    Conclusion

    Elastomeric chains in both the citric acid and artificial saliva groups experienced force decay over time. Force decay was greater in the citric acid group.Thus, citric acid can effectively decrease the elastomeric chain force. The Ortho Technology chain force was higher than that of American Orthodontics in both the groups at all time points.

    Keywords: Biodegradation, citric acid, elastomeric
  • Shiva Alavi, Atefe Ahmadvand Page 2
    Background

    The present study was performed to evaluate the effect of three types of mouthwash (orthokin, oral B and chlorhexidine [CHX]) on releasing of aluminum (Al), Titanium (Ti) and Vanadium (V) ions from titanium mini‑implants (TMIs).

    Materials and Methods

    In this in vitro, experimental study, a total of 40 TMIs were divided equally into four groups (10 TMI in each group) and then were immersed into Orthokin, Oral B, CHX, and artificial saliva, as a control. The experiments were performed for 21 days as following groups 1–7 days, 8–14 days, and 15–21 days. The inductively coupled plasma‑optical emission spectrometry method was used to assess releasing metal ions after immersion in the storage media. In addition, before and after each experiment, the corrosion of TMIs was assessed using a scanning electron microscope (SEM). All results were analyzed using Kruskal–Wallis, followed by Bonferroni‑adjusted Mann–Whitney U‑test at 0.05 level of significance.

    Results

    Our data showed that the maximum concentration of released Al was in the 1st week of exposure to Orthokin and Oral B (202.3 ± 68.5 and 72.3 ± 15.2 µg/L, respectively). Oral B exposure of TMI also caused to releasing of Ti to 128.1 ± 42.5, 54 ± 19.4 and 22 ± 6 µg/L for 1–7 days and 8–14 days and 15–21 days, respectively. Orthokin and CHX also induced the release of Ti more than artificial saliva (P < 0.05). In addition, there was no significant statistical difference between any types of mouthwashes and artificial saliva in releasing V. The results of SEM images also confirmed the corrosion effects of mouthwashes.

    Conclusion

    The factors of exposure time and mouthwash type influenced the pattern of releasing Al and Ti as well as corrosion level.

    Keywords: : Corrosion, mouthwashes, scanning electron microscopy, titanium alloy tial6 v4
  • Fahimeh Rezazadeh, Ali Dehghani Nazhvani, Samira Sadat Abolmaali, Fatemeh Dehghani Nazhvani, Alireza Bonyani Page 3
    Background

    There are many treatment protocols for relieving pain and accelerating oral ulcer healing. The purpose was to evaluate the anti‑inflammatory and antimicrobial effect of silver nanoparticle (AgNP) gel on oral ulcers compared with the traditional treatment in animal model.

    Materials and Methods

    In this experimental study, 72 adult male rats were randomly allocated into four groups, after ulcer induction: control (receive no treatment), placebo (placebo gel was applied on ulcers once daily), triamcinolone (ulcers were treated with triamcinolone paste once daily), and AgNPs (ulcers were treated with AgNP gel once daily). The animals were sacrificed at three successive periods of 3, 7, and 14 days after ulcer induction. Histopathological scores of re‑epithelialization and degree of inflammation were assessed. The wound size was measured clinically. For parametric data, the analysis of variance, and for ordinal histopathological data, the Kruskal–Wallis test using SPSS was done. A P < 0.05 was considered statically significant.

    Results

    Control and placebo groups had no case of complete healing. Improvement of wound size by triamcinolone paste was not significant in different days but showed significant differences in degree of inflammation (P < 0.001) and re‑epithelialization (P = 0.012). Reduction of wound size by AgNPs gel had significant difference at 14th day (P < 0.001); further, by this gel, significant differences in degree of inflammation and re‑epithelialization were seen in long‑term medication.

    Conclusion

    AgNP gel could be effective in oral ulcer healing clinically and histopathologically. Although this gel showed delayed effect, it had better healing effect according to the cases with complete healing. Hence, the application of AgNP oral gel can be considered as an alternative approach for oral ulcers.

    Keywords: : Inflammation, nanoparticle, oral ulcer, re‑epithelialization, silver, triamcinoloneacetonide, wound healing
  • Mehdi Abrishami, Arash Golestaneh, Laleh Maleki, Hasan Momeni, Mazyar Manshaei Page 4
    Background

    Infraorbital nerve injury often occurs due to zygomatic complex fracture. There is no standard protocol to restore the sensory and motor function of the nerve after injury. Some medications are used to improve nerve function. This histopathological animal study aimed to assess the neurotrophic efficacy of exenatide, ozone, and methyl prednisolone for injured infraorbital nerve.

    Materials and Methods

    In this animal study, 60 rats were randomly divided into five groups (n = 12) of control, saline, methyl prednisolone, exenatide, and ozone. Under general anesthesia, a unilateral infraorbital incision was made, and the nerve was compressed with a hemostat for 5 s. Depending on the study group, the rats received the designated medications. All rats were sacrificed after 14 days, and the nerve recovery was evaluated by observing the slides prepared from the area under a light microscope using histological and immunohistochemical parameters. Data were analyzed using Chi‑square test and Tukey’s least significant difference test (P < 0.05).

    Results

    No inflammation in the peripheral tissue had a significantly higher frequency in the methyl prednisolone group (P < 0.05). Degeneration, intracellular inflammatory infiltrate, muscle injury, fibrosis around the nerve, granulation tissue, vascular proliferation, and infiltration of inflammatory cells around the nerve were more commonly absent in the exenatide group (P < 0.05).

    Conclusion

    Exenatide showed superior efficacy for the recovery of infraorbital nerve function after injury. Thus, it may be beneficial for postoperative care following infraorbital nerve injury.

    Keywords: Exenatide, infraorbital nerve, methylprednisolone, nerve injury, ozone
  • V. V. Anusai, S. Shylaja, M. Suvarna, O. V. Ramanand, E. Sharath Reddy, V. Raghu Vamshi Page 5
    Background

    Odontogenic cysts and tumors exhibit varying degrees of aggressiveness in their biological behavior. Odontogenic keratocyst (OKC), dentigerous cyst (DC), ameloblastoma are most common odontogenic cysts and tumors to occur in the oral cavity. Myofibroblasts (MFs) in the connective tissue stroma participate in the matrix degradation process by secreting matrix metalloproteinase 2, transforming growth factor beta1 and may contribute to variation in their biological behavior. Its activity is identified by alpha‑smooth muscle actin (α‑SMA) marker. With this background, the present study aims to evaluate the frequency of MFs using α‑SMA to determine the biological behavior of OKC, DC, and different clinical variants of ameloblastoma.

    Materials and Methods

    A retrospective study was carried out with total of 60 samples which include 10 cases each of OKC, DC, 30 cases of different clinical variants of ameloblastomas and 10 normal mucosa taken as controls. All are stained immunohistochemically using α‑SMA and were analyzed for the same. Comparison between more than 2 groups done by one way analysis of variance test with the level of significance of P ≤ 0.0001, i.e., <0.05.

    Results

    Statistically significant difference in the mean number of MFs observed between certain groups, with higher mean number in solid ameloblastoma (SA) (32.45) followed by OKC (28.79), unicystic ameloblastoma (24.53), desmoplastic ameloblastoma (7.44), and DC (1.72).

    Conclusion

    Higher frequency of MFs noticed in SA, OKC which are key cells for connective tissue remodeling by interacting with epithelial cells and other connective tissue cells to facilitate progression of cysts and tumors thereby contributing to their biological behavior

    Keywords: Actins, ameloblastoma, matrix metalloproteinase 2, myofibroblasts, odontogeniccysts, transforming growth factor beta1
  • Mehrfam Khoshkhounejad, Mohammadreza Sharifian, Hadi Assadian, Mahsa Sobhi Afshar Page 6
    Background

    Conventional drug mixtures used in regenerative endodontic procedures have a toxic effect and no consensus has been reached about their best composition and concentration. Therefore, the aim of this study was to determine minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and minimum biofilm inhibitory concentration (MBIC) of the antimicrobial preparations and to compare their antimicrobial efficacy on bovine dentin infected by Enterococcus faecalis.

    Materials and Methods

    For this original ex vivo investigation, prepared concentrations (MIC, MBC, and MBIC) of triple antibiotic paste (TAP), double antibiotic paste (DAP), modified triple antibiotic paste (MTAP)‑1, MTAP2, co‑amoxiclav, and calcium hydroxide (CH) were added to the prepared bovine dentin blocks (which incubated in E.faecalis suspension previously) and incubated for 3 days. The samples were subsequently prepared for culture and CFU counts. Statistical analysis of data was carried out using one‑way analysis of variance and post hoc tests. The statistical power was set at P < 0.05.

    Results

    All medicament groups significantly showed an antimicrobial efficacy compared with negative control (without antibiotic) (P < 0.001). TAP, DAP, co‑amoxiclav, and CH (at its MBC value) were significantly capable of eliminating E. faecalis biofilm and showed no significant difference in comparison with positive control (complete biofilm removal) (P < 0.05).

    Conclusion

    TAP, DAP, co‑amoxiclav, and CH (at its MBC value) could effectively eliminate biofilm bacteria on the dentin surface. Antimicrobial efficacy of other medicaments containing cefaclor or clindamycin was limited.

    Keywords: Biofilms, Enterococcus faecalis, regenerative endodontics
  • Siamak Hemmatpour, Parastesh Molladavoodi, Fatemeh Kadkhodaei Oliadarani, Hossein Bahrani, Vahid Rakhshan Page 7
    Background

    Since there is no comparison between the effects of Sabbagh Universal Spring 2 (SUS2) appliance on Class II division 1 (div 1) versus Class II division 2 (div 2) patients, this preliminary study was conducted to comparatively assess, for the first time, the effects of SUS2 on 34 cephalometric indices in Class II/1 versus Class II/2 patients.

    Materials and Methods

    This before–after clinical trial was conducted on 75 observations of 25 patients with Class II malocclusion, of whom 12 (9 females and 3 males) had Class II div 1 and 13 (11 females and 2 males) had Class II div 2 malocclusion diagnosed by clinical examination and cephalometric assessment. The growth level of all patients had to be CS3 according to the cervical vertebral maturation index. Lateral cephalographs were obtained before treatment (T0) and the patients underwent fixed orthodontic treatment. Lateral cephalographs were taken again (T1) and the patients received SUS2 functional appliance for 6 months. A final lateral cephalograph (T2) was then obtained. Thirty‑four dentoskeletal indices were measured on lateral cephalographs, and changes in indices over time were determined and compared using repeated‑measures analysis of variance, post hoc test, and t‑test (α =0.05).

    Results

    Within‑group comparisons showed significant changes over time in SNB, sella nasion (SN)/occlusal plane, ANB, articular(Ar)‑pogonion (Pog), L1‑NB, condylion (Co)‑gnathion , S‑Ar/Ar‑G, B‑RL1, L1/nasion‑point B (NB), U6‑RL2, incisor mandibular plane angle, overjet, overbite, U1‑RL1, and L1‑RL2 (P < 0.05). The two groups were significantly different in terms of changes occurred to overjet, interincisal angle, U1/RL1, L1‑NB, U1‑NA, U1/NA, the Jarabak ratio, A‑RL1, U1/SN, Pog‑NB, and Co‑A (P < 0.05).

    Conclusion

    The SUS2 showed therapeutic efficacy for both Class II div 1 and 2 patients although it more commonly caused dentoalveolar rather than skeletal changes. Our study showed no considerable difference between the two groups after using this appliance, and the difference in the Jarabak ratio indicated better long‑term growth pattern of div 2 patients and its conformity with camouflage treatments (mild or moderate Class II).

    Keywords: Class II malocclusion, division 1, division 2, malocclusion, fixed functional appliance
  • Masoumeh Faramarzi, Mehrnoosh Sadighi, Mohammadtaghi Chitsazi, Mahdieh Esmailzadeh, Ghazale Foladvand Page 8
    Background

    Ferritin is an acute‑phase protein that is increased in inflammatory diseases. Melatonin has been studied due to its antioxidant effects and the elimination of free radicals. The aim of this study was to evaluate the effect of melatonin supplement as an adjunct to routine periodontal treatment on serum ferritin levels in patients with periodontitis.

    Materials and Methods

    Forty patients with chronic periodontitis were included in this randomized controlled clinical trial study. Twenty patients received nonsurgical periodontal treatment and twenty patients received nonsurgical periodontal treatment with adjunctive use of melatonin. Serum ferritin concentrations and periodontal parameters were recorded at baseline and 3 months after periodontal therapy. Serum ferritin level and periodontal parameters comparison at baseline and 3 months after periodontal treatment was done by Wilcoxon signed‑rank test and paired sample t‑test, respectively. Differences between test and control groups were evaluated by Mann–Whitney U‑test for ferritin level and independent t‑test for periodontal parameters, and a P ≤ 0.05 was considered statistically significant.

    Results

    Serum ferritin level decreased in both the control and test group in 3 months follow‑up compared to baseline (P < 0.001). The reduction in ferritin levels in the test group was more than the control group, but this difference was not statistically significant (P = 0.414). Improvement in periodontal parameters were not significant between two groups (P = 0.489), but improvement rates in the test group were more than control.

    Conclusion

    Melatonin, as an adjunct to periodontal therapy, showed additional benefits in the reduction of serum ferritin levels and improvement of periodontal parameters.

    Keywords: Chronic periodontitis, dental scaling, ferritin, inflammation melatonin
  • Seyed Mohsen Hasheminia, Mojdeh Mehdizadeh, Shervin Bagherieh Page 9
    Background

    Appropriate cleaning and shaping and three‑dimensional obturation of the root canal system lead to a successful endodontic treatment. To achieve this, complete knowledge of the internal anatomy of root canals is necessary. Therefore, this study evaluated the number and shape of mandibular premolar roots and canals and classified their Vertucci classification using cone‑beam computed tomography (CBCT) images of an Iranian sample population.

    Materials and Methods

    This in vivo study was performed on CBCT images of patients aged 20–70 years who had attended a dental radiology center in Isfahan. CBCT images were examined in coronal, sagittal, and especially axial dimensions. Descriptive statistics were calculated. Groups were compared using the Chi‑square of the Statistical Package for the Social Sciences. The level of significance was predetermined as 0.05.

    Results

    In both first and second premolars, the most common classes were Type I followed by TypeV. The Chi‑square did not show significant differences between males and females in terms of Vertucci classes in the first (P = 0.305) or second premolar (P = 0.315).

    Conclusion

    Since a thorough knowledge of root canal anatomy is necessary for successful root canal treatment and almost one out of ten mandibular premolars has additional canal in their root canal system, accurate evaluating of preoperative radiographs, taking CBCT images if necessary, and probing the root canal system with fine and precurved files should be done to negotiate the entire canal system.

    Keywords: Bicuspid, cone‑beam computed tomography, root canal therapy
  • Zahra Hashemi Ardakani, Rashin Giti, Shima Dabiri, Amir Hashemi Hosseini, Marzieh Moayedi Page 10
    Background

    The flexural strength (FS) of a denture base material is of great concern, and many approaches have been used to strengthen the denture acrylic resins. The present study aimed to evaluate the effect of high‑performance polymer (BioHPP) and metal mesh reinforcement on the FS of a heat‑cured poly methyl methacrylate (PMMA) acrylic resin.

    Materials and Methods

    This experimental study was done on 30 rectangular specimens (64 mm × 13 mm × 3 mm) of a heat‑cured PMMA resin. The specimens were divided into three groups (n = 10) to be reinforced with either metal mesh or BioHPP mesh; one group was left nonreinforced, serving as the control group. The FS of specimens was assessed through a 3‑point bending test by using a universal testing machine at a crosshead speed of 2 mm/min. Kruskal–Wallis H and Dunn’s post hoc tests were used to compare the FS among the groups (alpha = 0.05).

    Results

    The FS in the metal‑reinforced group was statistically significantly higher than the two other groups (P < 0.001). However, the FS of the BioHPP‑reinforced samples was not statistically significantly higher than the nonreinforced ones (P = 0.614).

    Conclusion

    Reinforcing the PMMA with metal mesh significantly enhances its FS while BioHPP has no significant effect on the PMMA FS.

    Keywords: Flexural strength, polyetheretherketone, polymethyl methacrylate, reinforcement
  • Silvio Taschieri, Gianluca Gambarini, Irina Makeeva, Svetlana Tarasenko, Stefano Corbella Page 11

    The aim of the present study was to describe two clinical cases showing postoperative pain associated with the use of plastic carrier obturation system and apical bone fenestration. The patients were treated by surgical access and apicoectomy through a modern technique (using magnification and microsurgical approach), thus removing the direct contact between obturation material and submucosal connective tissue. The surgical interventions were carried on without the occurrence of any complication. Postsurgical adverse sequelae were negligible. After few weeks from the surgery, all symptoms disappeared. Radiographic healing was observed after 48 months. The presence of apical bone fenestration could be the cause of persistent pain after root canal treatment. The contact between plastic carrier and submucosal connective tissue could be the direct cause of spontaneous pain even in absence of periapical infection. Since the clinical diagnosis could be difficult, the use of tridimensional radiology could be justified. Surgical approach, by the removal of the contact between the carrier and connective tissues, can be considered a viable option to treat these particular affections.

    Keywords: Apicoectomy, endodontics, pain, root canal obturation