Journal of Dental School, Shahid Beheshti University of Medical Sciences

Objectives Facial asymmetry in orthodontic treatments can be evaluated by both posteroanterior (PA) cephalograms and cone-beam computed tomography (CBCT) images. This study aimed to assess the agreement between CBCT and two-dimensional PA images in terms of cephalometric measurements.

Methods In this descriptive analytical study, CBCT and PA radiographs were taken from nine human dry skulls. Two observers marked the bilateral landmarks including CO (orbit center), J (jugale), 6C, 6A, 1A, 1C, GO (gonial angle), AG (antegonion), AR (articular) and Ma (mastoidal). The distance between two identical points on both sides was measured on both the PA and CBCT images. The differences were calculated and the agreement between the two modalities was checked by using intraclass correlation coefficient (ICC).

Results The mean differences between CBCT and PA measurements were as following: for CO=1.48, J=11.64, U6C=0.75, U6A=1.8, L6C=13.33, L6A=3.0, U1C=0.96, U1A=0.62, L1C=0.22, L1A=0.45, GO=0.87, AG=6.67 and AR=0.71 mm. The agreement was the highest for GO (ICC=0.931) and CO (ICC=0.902), and the lowest for U6A (ICC=-0.041) and J (ICC=0.038) landmarks.

Conclusion Given the negligible differences between the two modalities, conventional PA cephalograms can be as competent as CBCT in detecting maxillofacial asymmetry with lower patient radiation dose.

Objectives This study assessed the mandibular buccal shelf (MBS) for safe miniscrews insertion in teenagers and adults.

Methods Cone-beam computed tomography (CBCT) images of 30 teenagers and 30 adults were used to measure bone width and cortical bone thickness. Measurements were made at four sites buccal to the distobuccal cusp of mandibular 1st molar (D6), and mesiobuccal cusp (MB7), an area at the center of the bifurcation (Mid7), and distobuccal cusp (DB7) of mandibular second molar. Bone width was measured at four distances (4, 6, 8, and 10 mm) from the (CEJ). ANOVA was used for statistical analysis.

Results The MBS was significantly different within each age group and in different age groups, tooth sites, distances from the CEJ, and cortical bone thicknesses (P<0.001). A significant difference was detected in bone width between the two age groups in D6 at all distances from the CEJ, MB7 and Mid7 at 4 mm and 6 mm, and DB7 at 4 mm from the CEJ (P<0.05). Cortical bone thickness was significantly different between the two groups at MB7, Mid7, and DB7 (P<0.05).

Conclusion All distances from the CEJ at DB7 offered adequate bone width for safe miniscrew implantation. Mid7 showed suitable bone width at all distances from the CEJ in teenagers. In adults, miniscrews should be implanted at 6 mm from the CEJ. Miniscrews should be inserted in at least 8 mm distance from the CEJ at MB7. D6 is unsafe for miniscrew insertion in both groups at all distances from the CEJ.

Objectives Health education for school-age children is a specialized component of the oral health promotion program. This study aimed to design and develop an oral health educational game and assess its effect on the oral health of children aged 8 to 12 years.

Methods In this experimental study, 40 patients aged 8-12 years referring to a private dental clinic were selected by using convenience sampling and were then randomly assigned to the experimental and control groups. The experimental group received oral health training by using a game; while, the control group received oral hygiene instructions. The simplified oral hygiene index (OHI-S) with two components of debris index (DI-S) and calculus index (CI-S) was measured before the intervention, and at one week, and one month after the intervention to assess the effect of oral health skills. Data were analyzed by the Chi-square test, independent sample t-test, and Fisher's exact test.

Results The DI-S scores in the experimental group at one week and one month after the intervention were significantly lower than the values in the control group (P=0.003 and P=0.001, respectively). The OHI-S scores in the experimental group at one week and one month after the intervention were significantly lower than the values in the control group (P=0.012 and P=0.007, respectively). No significant difference was noticed in the follow-up CI-S scores at one week and one month after the intervention (P>0.05).

Conclusion The game designed in this study would improve the children's oral health skills; hence, it can be used to promote oral health in children.

Objectives Evaluation of the properties of recently introduced bulk-fill composite resins from different aspects is important. We aimed to evaluate the compressive strength of two bulk-fill composite resins with different viscosities compared with one conventional composite resin.

Methods This in vitro study evaluated two different bulk-fill composite resins and one conventional composite resin. Twelve samples were prepared for each group in a mold, measuring 4 mm in diameter and 6 mm in height. In group 1, x-tra fil bulk-fill composite resin was light-cured with 4-mm thickness for 40 seconds. Then, a 2-mm thick increment of composite resin from the same brand was placed over it and light-cured. In group 2, x-tra base composite resin was light-cured with 4 mm thickness. Then, Grandio conventional composite resin was placed over it with 2-mm thickness and light-cured. In group 3, Grandio conventional composite resin was placed in 2-mm thickness using the incremental technique and light-cured. The samples were stored in distilled water at 37°C for 48 hours, followed by the compressive strength test in a universal testing machine at a crosshead speed of 1 mm/minute. The data were analyzed with SPSS 21 using one-way ANOVA and post hoc Tukey’s test. Statistical significance was set at P<0.05.

Results There were no significant differences in compressive strength values of the three study groups (P>0.05).

Conclusion The bulk-fill composite resins evaluated in the present study exhibited compressive strength values similar to that of the conventional composite resin, indicating favorable compressive strength, with decreased working time.

Objectives Dental materials are potentially hazardous and can negatively affect the health of patients, dental staff, and the surrounding environment. Thus, it is important to be aware and comply with the information provided in the material safety data sheets (MSDSs). Therefore, it seems necessary to review the dental material safety sheets in order to determine their consistency with the standard safety items required for dental materials. This study aimed to evaluate the MSDSs of dental materials consumed in Kerman Dental School to determine their compliance with the standard safety items.

Methods In this cross-sectional study, 106 dental materials were selected from 12 clinical departments of Kerman Dental School. The MSDSs were assessed in order to determine their consistency with the standard safety items. Data were analyzed with SPSS version 21, and t-test was used for statistical analysis. Statistical significance level was set at P<0.05.

Results Among the 15 items considered necessary according to the standard MSDSs, the item “necessary measures in case of possible leakage and spillage” had been least frequently stated in the assessed MSDSs. Also, the mean safety score of the materials with MSDSs was significantly higher compared with materials that had no MSDSs(P=0.0001).

Conclusion Evaluation of the MSDSs of dental materials consumed in Kerman Dental School regarding the required standard items revealed that they did not meet the defined standard levels.

Objectives Microorganisms are the main culprits responsible for many oral conditions including dental caries and periodontal diseases. To increase the quality of dental treatments, we can produce dental materials with antimicrobial properties. Nanoparticles with their antimicrobial activities can help achieve this goal. The purpose of this study was to describe the applications of nanoparticles in different fields of dentistry.

Methods An electronic search was conducted in the PubMed and Google Scholar to find articles related to the applications of nanoparticles in dentistry. No limitations were set regarding the date of publication or the language. We selected 73 articles and summed up the information.

Results Nanoparticles can be effectively used in various fields of dentistry including prosthodontics, oral medicine, periodontics, implant therapy, bone augmentation, restorative and preventive dentistry, orthodontics and endodontics, as well as in dental office disinfectants.

Conclusion Incorporating nanoparticles into dental materials is the most common application of nanoparticles in dentistry, which leads to an increase in antimicrobial properties of dental materials. Cancer diagnosis and treatment, regeneration of alveolar bone defects, and treatment of tooth hypersensitivity are the other emerging applications of nanoparticles in dentistry. 

Objectives Implant-retained maxillofacial prostheses have proven to be more successful than conventional adhesive-retained prostheses. Implants enhance prosthesis stability and retention through retentive attachments. However, a faulty abutment-implant interface in terms of complete seating and passive fit could be responsible for mechanical and/or biological complications. This case report describes a simple imaging method to check this adaptation.

Case: In our case, two shoulder type maxillofacial implants with 4 mm length and diameter were placed with 15 mm distance using a surgical guide. After completion of the healing course and making an impression, a metal bar attachment was made and tried on. In addition to using conventional methods to check the complete and correct seating of the suprastructure (bar attachment), a modified posterior-anterior radiograph with a 15-degree downward head tilt was taken. After confirming the seating of the attachment, the auricular prosthesis was made accordingly.

Conclusion Use of radiography to ensure the seating of intraoral implant-supported frameworks is common and accurate. However, there is no radiographic imaging method to check the fit of extraoral implant-supported substructures. This case report described a simple and effective radiographic technique for auricular implant supported by a substructure which is especially important in case of presence of thick skin around the implants, which compromises the accuracy of direct exploring.

Objectives Neurofibroma (solitary or multiple) is a benign neurogenic jaw tumor with peripheral nerve origin. It is commonly found in the skin and the head and neck region but its occurrence in the oral cavity is rare.

Case: This report presents a case of huge solitary neurofibroma in the maxillary vestibular mucosa in a 60-year-old male without any medical or family history of neurofibromatosis type 1. The diagnosis was made based on histopathological findings and IHC staining for the S-100 protein. No recurrence was noted at the 6-month follow-up after surgical excision of the lesion.

Conclusion We reported a case of neurofibroma, which is a relatively rare benign tumor of the oral cavity, in the buccal mucosa in an elderly man based on histopathological and immunohistochemical findings. The propensity of neurofibromas to progress to neurofibromatosis or the primary disease undergoing malignant transformation (6-29%) has been reported in the literature. Therefore, a close follow-up of patients presenting initially only with neurofibroma is necessary.