Journal of Research in Dental and Maxillofacial Sciences
Volume:6 Issue: 2, Spring 2021

The aim of this study was to compare the cytotoxicity of ProRoot MTA and Endocem at different times and concentrations on human gingival fibroblasts.

In this in-vitro study, ProRoot MTA and Endocem extracts with concentrations of 3, 6, 12, 25, and 50 mg/ml in the unhardened state (solution) at 24, 48, and 72 hours on human gingival fibroblasts were transferred to 96-well plates in Dulbeccochr('39')s Modified Eaglechr('39')s medium (DMEM). For each material at any time and any concentration, three wells were used, and 90 samples were examined. Also, to calibrate the cytotoxicity measuring device at 24, 48, and 72 hours, 3 wells for positive control and 3 wells for negative control have been considered, which include a total of 9 positive control wells and 9 negative control wells. Samples were analyzed by MTT assay. Data were analyzed by analysis of variance (ANOVA).

In the present study, the samples in the two groups at different times and concentrations did not show a significant difference in terms of cytotoxicity (P<0.05). The highest cytotoxicity was related to Endocem at 24 hours and a concentration of 50 mg/ml, and the lowest was related to ProRoot MTA at 72 hours and a concentration of 6 mg/ml.

According to the research, in general, the degree of cytotoxicity of Endocem is comparable to that of ProRoot MTA.

The rapid outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, China has led to a public health crisis. Dental professionals have a major role in preventing the viral infection cycle. This study targeted to investigate the knowledge of 140 dental assistants in Tehran, Iran, about COVID-19.

A cross-sectional survey was conducted in Tehran, Iran, using a 27-item questionnaire, which consisted of 7 multiple-choice questions about the demographic information of the participants and 20 multiple-choice questions about their awareness. The data were analyzed with multivariable generalized estimating equations (GEE) using student t-test.

A total of 140 participants (22 males and 118 females with a mean age of 29.40±6.21 years) responded to the questionnaire. The majority of respondents (91.4%) mentioned cough and fever as the main symptoms of COVID-19 infection. Tooth extraction and root canal therapy were mentioned as emergency treatments according to 98.6% of respondents. 89.3% of respondents chose phone calls as the best screening tool. The knowledge and attitude of participants showed a significant correlation with their educational degree.

The knowledge of dental assistants about COVID-19 infection was fair. The participants’ awareness showed no correlation with their gender, work experience, place of occupation, and the specialty of the dentist that they assist.

Considering the lack of sufficient and even contradictory studies on the effect of temperature-dependent dimensional changes of alginate before pouring, this study aimed to investigate the effect of storage temperature of Hygedent and Chromogel alginate molds on dimensional stability. 

In this in-vitro experimental study, dimensional changes of two types of alginate were investigated indirectly by measuring a type III stone cast. Ninety molds of each alginate were obtained from a metal model and stored at 1±4, 1±25, and 1±40°C. The casting was performed 12 minutes, 1 hour, and 4 hours after impression taking. The molds were incubated with an approximate humidity of 100%. The diameter, width, and height of the gypsum casts were measured by a digital caliper with an accuracy of 0.01 mm. Dimensional changes of two alginates in three separate directions were statistically analyzed by three-way analysis of variance (ANOVA) and post-hoc test due to the significant difference.

There was no statistically significant difference in width changes at different temperatures, but regarding the diameter, there was a significant difference between 40°C Chromogel and 25°C Hygedent. Regarding the height, only 40°C Hygedent showed a significant difference at 4 hours compared to 12 minutes (P=0.000, 0.26, and 0.000, respectively). However, no statistically significant difference was observed in other temperatures and times (P>0.05). In most groups, dimensional changes of all samples were not within the clinical standard range (1%).

It seems that the dimensional stability of Hygedent and Chromogel alginates is affected by storage temperature, pouring time, and type of alginate.

The paranasal sinuses are known for their complex anatomy and significant difference in size and shape. This study aimed to determine the prevalence of anatomical variations of the paranasal sinuses in computed tomography (CT).

In this cross-sectional study, patients over 18 years of age, who had undergone CT imaging in a private clinic, were screened for eligibility of participation. After excluding the patients with evident sinus pathology in CT, 501 cases were included. An experienced maxillofacial radiologist evaluated the CT images and extracted the frequency of variations using a standardized data collection sheet. Kolmogorov-Smirnov test, independent samples t-test, and chi-square test were used for the statistical analysis.

Among the studied variations, septal deviation and Agger nasi, each with 336 cases (67.1%), and concha bullosa, with 240 cases (47.9%), were identified as the most common anatomical variations of the paranasal sinuses. The uncinate bulla showed a significant correlation with gender (P=0.036).

Considering the remarkable prevalence of some important variations, which may increase the risk of complications in sinus surgery, CT evaluation of patients is recommended before surgical interventions in the sinuses.

Oral cancer is a major public health problem worldwide and is among the ten most common cancers. Despite the advances in research and treatment, oral cancer is still one of the major challenges in medical science. Common treatments for this cancer include surgery, radiotherapy, and chemotherapy, as well as adjuvant photodynamic therapy (PDT). The aim of this study was to evaluate oral cancer and its treatment methods with an emphasis on the use of adjuvant PDT. The present study is a review performed by searching the articles published in the past 20 years (2000-2020) in Elsevier, PubMed, Springer, and Wiley databases with “oral cancer”, “photodynamic therapy”, and “treatment modalities” keywords. Research shows that PDT can be an effective way to treat oral cancer due to its few side effects and minimal invasion. However, accurate evaluation of the efficacy of PDT requires further studies.

Chairside computer-aided design/computer-aided manufacturing (CAD/CAM) systems have become considerably more accurate, reliable, efficient, fast, and prevalent since 1985 when CEREC was introduced. The inceptive restorative material option for chairside CAD/CAM restorations was limited to ceramic blocks. Today, restorative material options have been multiplied and include metal alloys, ceramics, oxide ceramics, resins, and resin-matrix ceramics (RMC). This study aimed at making an overview of chairside CAD/CAM system materials and classifications.

An electronic search of the literature was carried out mainly through PubMed, ScienceDirect, Cochrane Library, and Google databases. The search aimed at collecting all the relevant English articles from 1965 to 2020.

The analysis of the bond strength, fatigue resistance, flexural strength, elastic constants, microstructural characterization, accuracy, and clinical success of the materials showed variable outcomes. The marginal adaptation of resin ceramics has been reported to be comparable to that of lithium disilicate. It has been reported that the chairside CAD/CAM system using intraoral scanning is at least as accurate as the conventional method.

Chairside CAD/CAM restorations are fast, reliable, predictable, effective, patient-friendly, and cost-effective treatment options. Design software and intraoral scanners have made the treatment procedure simple. Chairside individualization of dental restorations could help improve patient satisfaction. However, considering the limited long-term clinical data, future studies need to address the long-term clinical performance of chairside CAD/CAM materials.

Computer-aided design/computer-aided manufacturing (CAD/CAM) has been widely used in implant dentistry. Recent computer-guided dynamic navigation systems promise an accurate approach to minimally invasive implant placement. Robot-assisted surgery has been used in dentistry since 2017. The present study aims to review the properties, clinical outcomes, advantages, and limitations of navigation, robotics, and CAD/CAM in implant placement surgery.

An electronic search of the literature was conducted mainly through PubMed, ScienceDirect, Cochrane Library, and Google Scholar databases. Studies in the English language were considered for inclusion if they evaluated robotics, CAD/CAM, and navigation in implant placement. Finally, 21 articles were selected.

Guided implant surgery is assumed accurate, precise, and reliable; it also has a lower complication rate compared to freehanded implant surgery. Surgical guides could be indicated for patients with limited mouth opening, tight interdental spaces, a strong gag reflex, and distal implants. Several studies have reported that computer-assisted surgery improves the accuracy of implant placement. Expensive equipment, high costs, and gaps between the guides and drill bite are the disadvantages of digital implant placement.

Computer-aided implant navigation systems can improve implant placement outcomes. Digital procedures have shown accurate outcomes in implant surgery. Despite the advantages of guided surgery, deviation of implant position from the planned position still occurs. However, improvements in digital dentistry are slowly overcoming these challenges.