فهرست مطالب

Dental Materials and Techniques - Volume:8 Issue:3, 2019
  • Volume:8 Issue:3, 2019
  • تاریخ انتشار: 1398/06/10
  • تعداد عناوین: 8
|
  • Zahra Bahrololoomi, Sahar Salajeghe, Setare Shahini Tiran* Pages 107-113
    Introduction
    Disinfection of the cavity preparation after caries excavation can lead to the elimination of bacterial remnants that can be responsible for recurrent caries, postoperative sensitivity, and failure of the restoration. The purpose of this study was to evaluate the effects of two disinfectants on microleakage of composite restorations in primary teeth.
    Methods
    In this experimental study, 40 extracted primary canine teeth without caries were randomly divided into four groups of 10 teeth, namely control group (1), pretreatment group with chlorhexidine 2% (2), pretreatment group with sodium hypochlorite 2/5% (3), and pretreatment group with sodium hypochlorite 5% (4). In addition, class V cavities were prepared on all teeth. The cavities were then restored with composite. The teeth were thermocycled and immersed in 2% methylene blue for 24h. Microleakage was assessed by dye penetration in the incisal and gingival surface of the teeth using stereomicroscope. Data were analyzed in SPSS software (version 18) through Kruskal-Wallis and Mann-Whitney U tests.
    Results
    According to the results, the difference among groups was significant (P
    Keywords: Chlorhexidine, composite restorations, Disinfectant agent, Microleakage, primary teeth, Sodium Hypochlorite
  • Alaa M. Attaallah*, Eman M Zayed, Salma M Dabees, Youssef Y Ashour, Amal Ezz, Eldin Fahmy Pages 114-120
    Introduction
    There has been a growing interest in glass ceramic systems with good esthetics, high fracture resistance, bonding durability, and simplified fabrication techniques using CAD/CAM. The aim of this study was to compare flexural strength in "polished" and "glazed and fired" specimens of zirconium lithium silicate (ZLS) CAD/CAM blocks Celtra Duo.
    Methods
    A total of 14 specimens of Celtra Duo (Dentsply Sirona, Germany) were designated and equally divided into two groups, including group I (n=7; as polished) and group II (n=7; as glazed and fired) according to the manufacturers’ instructions. Then biaxial flexural strength was tested according to ISO 6872 using a universal testing machine and piston-on-three-ball method after polishing, glazing, and firing. The fractured surfaces and microstructure were observed by scanning electron microscope (Jeol/GSM5300). Data were then statistically analyzed using SPSS software (version 20.0).
    Results
    There were statistically significant differences in biaxial flexural strength between a polished and glaze-fired specimen of ZLS glass ceramic discs as biaxial flexural strength was lower in polished specimens (mean±standard deviation: 158.7±21.67 MPa), while the glazed specimens showed higher biaxial flexural strength (mean±standard deviation: 261.5±31.89 MPa).
    Conclusion
    Glazing and firing of Celtra Duo specimens increased biaxial flexural strength significantly in comparison to polishing with no significant change in the microstructure.
    Keywords: Celtra Duo, Piston-on-three-ball, CAD, CAM, ZLS
  • Seda Falakaloğlu*, Özkan Adıgüzel, Meryem Kara, Merve Yeniçeri Özata Pages 121-128
    Introduction
    The present study aimed to compare the cleaning efficacy of passive ultrasonic irrigation (PUI), self-adjusting file (SAF), EndoVac, and conventional syringe irrigation (CSI) techniques on Ca(OH)2 removal from the root canal.
    Methods
    This study was conducted on the mesial roots of 36 human mandibular molar teeth. After 1 month, the Ca(OH)2 was removed from the experimental groups using four different irrigation techniques (SAF, PUI, EndoVac, and CSI). The inner surfaces of the canals were examined using a stereomicroscope at 30x magnification. The assessment of remaining Ca(OH)2 medicament in the grooves was performed by three calibrated dentists using a scoring system ranged 0-3.
    Results
    None of the groups showed complete Ca(OH)2 removal from the root canals. The PUI technique removed significantly more Ca(OH)2  from all root canals, compared to EndoVac and CSI techniques  (P
    Keywords: Passive ultrasonic irrigation, self-adjusting file, EndoVac, conventional syringe irrigation
  • Hoorieh Bashizadeh Fakhar, Ahmadreza Shamshiri, Zahra Momeni, Mahdi Niknami*, Niloofar Kianvash Pages 129-134
    Introduction
    The aim of this study was to design a standard questionnaire facilitating the evaluation of the knowledge and attitude of medical students regarding radiation protection.
    Methods
    At first, a 30-item questionnaire was prepared. The scale construction procedure was performed using content validity assessment. Considering objectives, some items were designed based on textbooks and the ideas of oral radiologists, medical physicists, and occupational medicine specialists as the expert panel. Content validity of the draft was determined by the panel.
    Results
    Test-retest procedure was used to determine the reliability of the questionnaire by kappa statistic and Cronbach’s alpha coefficient. Experts evaluated the content validity as desirable. Kappa coefficient was more than 0.75 for almost all knowledge and attitude items. Cronbach’s alpha coefficients for basic knowledge, practical knowledge, and attitude domains were 0.793, 0.823, and 0.822, respectively.
    Conclusion
    The designed questionnaire was confirmed as reliable considering Iranian cultural concepts.
    Keywords: Questionnaire, Radiation Protection, Knowledge, Attitude, medical students
  • Shabnam Aghayan*, Roya Assadi, Abdolmajid Bayandori Moghaddam, Ehsan Seyedjafari Pages 135-142
    Introduction
      This study sought to assess the cytotoxic effects of nanoparticulate and microparticulate calcium sodium phosphosilicate mouthwashes on human gingival fibroblasts (HGFs).
    Methods
    This in vitro study was conducted on HGFs isolated and cultured in a 48-well plate containing standard culture medium for evaluation of four concentrations of the two mouthwashes at two time points plus a positive and a negative control group. The HGFs were exposed to 0.001, 0.01, 0.1 and 1 mg/mL concentrations of mouthwashes for 1 and 24 hours. Positive and negative control cells were exposed to saline and distilled water, respectively. Cell viability was assessed using the methyl thiazolyl tetrazolium (MTT) assay, and the number of viable cells was counted in triplicate using a cell counter after transfection (trypsin-EDTA 0.25%, 20 minutes) and exposure to trypan blue. The optical density (OD) values were read by ELISA reader and analyzed using the Kruskal-Wallis test.
    Results
    Number of viable cells was not significantly different between the two mouthwashes at the two time points (P>0.05). At one hour, number of viable cells was higher in the nanoparticulate group while the number of viable cells in the microparticulate group was higher at 24 hours.  
    Conclusion
    Nanoparticulate and microparticulate calcium sodium phosphosilicate mouthwashes have no cytotoxicity against HGFs. Cytotoxicity of the nanoparticulate mouthwash was less than that of the microparticulate mouthwash. Also, increased proliferation of fibroblasts was noted over time in both groups of mouthwashes.
    Keywords: Cytotoxicity, Human Gingival Fibroblasts, Mouthwash, Calcium Sodium Phosphosilicate, Nanoparticles
  • Fatemeh Mashhadiabbas, Nafise Shamloo*, Hasan Mirmohamad Sadeghi, Samane Ahmadi Pages 149-152
    Abstract Odontomas are the most common type of odontogenic tumors, which are often discovered by routine radiographic images or after taking films to determine the main cause of the tooth failure eruption or malocclusion. The present study aimed to describe a case of misdiagnosis and similarity of foreign body density in the radiographic appearance to odontoma in a 13-year-old male.
    Keywords: odontoma, Foreign body, Radiographic Appearance
  • Alireza Khoshsirat, Sahand Samieirad*, Maryam Hashemipour, Elahe Tohidi, Vajiheh Mianbandi Pages 153-158
    Abstract The prevalence of mandibular fracture is relatively lower in the pediatric population compared to adults. The treatment of these fractures is more challenging for oral and maxillofacial surgeons due to the concerns regarding mandible growth and the presence of developing tooth buds. According to the literature, conventional methods (e.g., soft diets or closed reduction) are more effective in the treatment of nondisplaced pediatric mandibular fractures. There are few case reports regarding the treatment of mandibular fractures in infants, which have mainly introduced new technique using double-crossed direct skeletal wires to reinforce circummandibular wirings for the conservative treatment of infantile mandibular fractures. The present study aimed to describe the case of a 12-month male infant with significant dislocated right mandibular parasymphysis fracture. Initially, two circummandibular wires were passed bilaterally to pull the mandibular segments for their vertical alignment. Afterwards, the skeletal buccal and lingual direct wires reinforced the previous circummandibular wiring to fit the fracture segments. Finally, all the wires were tightened simultaneously to maintain satisfactory bone reduction. Furthermore, the addition of skeletal buccal and lingual direct wires could reinforce the previous circummandibular wiring to fit the fracture segments anteroposteriorly. The fracture healed uneventfully with no complications, and intermaxillary fixation was not required in the patient. Moreover, the alveolar segments were in an appropriate position, and the maximum mouth opening of the patient was normal with no deviation, indicating a successful clinical outcome. This method was relatively reliable, noninvasive, and inexpensive, associated with the decreased discomfort and morbidity associated with maxillomandibular fixation, open reduction, and internal fixation in infants.
    Keywords: mandibular fracture, Closed reduction, Infant, Circummandibular wiring