Dental Research Journal
Volume:19 Issue: 10, Oct 2022

The main drawbacks of zirconia are its high refractive index and opacity. This study aimed to assess the effect of sintering temperature on the translucency of Ivoclar e. max ZirCAD (IEZ), and White Peaks Symphony (WPS) zirconia blocks.

In this in vitro experimental study, 30 IEZ and 30 WPS zirconia blocks measuring 10 mm × 10 mm × 1 mm were prepared and underwent sintering in three subgroups at 1440°C, 1500°C, and 1530°C. The specimens were then photographed against a black and a white background with a standard digital camera. The L*, a*, and b* color parameters were measured using Adobe Photoshop software, and translucency was calculated. Data were analyzed using one‑way ANOVA and Tukey’s test (P < 0.05).

In both the IEZ and WPS groups, the maximum and minimum translucency parameters were recorded in 1530°C and 1440°C subgroups, respectively. The difference in the mean translucency was significant among the three subgroups of each zirconia group (P < 0.001). The mean translucency of WPS zirconia was significantly higher than that of IEZ zirconia (P < 0.01), and maximum difference was noted at 1500°C sintering temperature.

Increasing the sintering temperature from 1440°C to 1530°C can significantly increase the translucency of IEZ and WPS zirconia blocks, and can be considered to improve the quality of zirconia restorations.

The restoration of speech, deglutition, mastication, and respiration in patients with bimaxillary resection involving the maxillae, hard and soft palates, and paranasal sinuses poses a significant challenge. This clinical report describes the prosthodontic management of a patient with bilateral maxillectomy caused due to post‑COVID‑19 mucormycosis. A patient-specific implants (PSI) that matched the remnants of the zygoma complex was designed to improve the patient’s severely impaired speech and swallowing. The patient’s postsurgical anatomy was first visualized using three‑dimensional computed tomography data. Following that, a customized zygoma‑supported titanium framework was designed to support the prosthesis based on the data. Two weeks after the framework was installed, an open‑tray impression was made and the prosthesis was fabricated. These findings suggest that PSI‑retained prosthesis can be considered in cases with severely compromised maxillary bone anatomy, impaired oral functioning, and no viable conventional reconstruction options.

Pulpotomy is one of the common vital pulp therapy procedures for primary molars. The present trend in pulpotomy materials is to use regenerative materials that promote dentinogenesis. Mineral trioxide aggregate (MTA) is a very popular pulpotomy material. However, it has some limitations including difficult handling characteristics and long setting time. Tricalcium silicate cements evolved, in which bioceramic cements came into existence, have better properties than MTA. The aims and objectives of the study are to evaluate the efficacy of bioceramic putty with MTA as a pulp medicament in primary molars.

In this randomized in vivo study, sixty primary molars in children aged 4–9 years indicated for pulpotomy were selected. They were assigned using nonprobability convenient sampling technique into two groups: test group – bioceramic putty (EndoSequence Root Repair Material) and control group – MTA (Angelus). After pulp therapy, teeth were restored with stainless steel crowns. Recall clinical and radiographic evaluation was done at 3‑, 6‑, and 12‑month interval to assess success rate. The data were statistically analyzed using Chi‑square test, and P ≤ 0.05 was set for statistical significance.

At 3‑month interval, the success rates were 96.7% and 93.1% with bioceramic and MTA groups, respectively. At 6‑ and 12‑month interval, the success rates were 93.3% and 93.1% with bioceramic and MTA groups, respectively. However, the difference in success rate between the groups was statistically not significant at all the time intervals (P = 0.533 at 3 months, P = 0.972 at 6 and 12 months).

Bioceramic putty exhibited comparable results to MTA. Hence, it can be considered alternative pulpotomy agent.

Chronic periodontitis (CP) is characterized by an immune response, leading to the destruction of periodontal supporting tissue. The effect of inflammatory and genetic factors on periodontitis has been evaluated previously. The interleukin (IL‑17) as an inflammation regulator seems to play a critical role in periodontitis pathogenesis. Here, in the current study, we aimed to investigate the association of ‑197 G > A (rs2275913) IL‑17 gene promoter polymorphism with generalized severe CP in an Iranian population.

In this case–control study, a total of 54 patients with periodontitis and 118 normals were enrolled. The polymerase chain reaction‑restriction fragment length polymorphism technique was applied to detect IL‑17 promoter rs2275913 genotypes in association with the susceptibility to severe CP. Chi‑square test or Fisher’s exact test was employed to compare genotype frequencies between groups. P < 0.05 were considered statistically significant.

The distribution of genotypes and alleles was in Hardy–Weinberg equilibrium. Although no significant association was observed between the risk of periodontitis and genotype frequencies under any of the inheritance models, the GG genotype was higher in healthy controls, while the AG genotype was more frequently observed in patients under the codominant model ([odd ratio [OR] = 2.14, 95% confidence interval (CI) (1.01–4.53), P = 0.13]). The frequency of AG‑AA genotype was higher in patients under dominant inheritance model ([OR = 1.92, 95% CI (0.94–3.93), P = 0.068]), while GG‑AA and AG genotypes were higher in healthy controls under over dominant model (OR = 0.1.95, 95% CI [0.98‑3.86], P = 0.055).

The results of this study showed that the presence of allele A and AG genotypes could be considered possible factors in increasing the risk of developing CP, although the differences of allele and genotype frequencies were remarkable but not statistically significant between the two groups.

The delayed diagnosis of oral squamous cell carcinoma (OSCC) affects therapeutic and prognostic strategies, and provides regional recurrence or distant metastasis. The tumor‑infiltrating lymphocytes (TILs) are known as a critical diagnostic biomarker in antitumor immune response. We evaluated the association between CD4+T‑lymphocyte marker, some clinicopathological indices, and the impact of TILs on the stage and grade of OSCC.

In this cross‑sectional study, 37 OSCC specimens including 16 early and 21 advanced stages (categorized base‑on recent clinical oncology references) and their related healthy surgical margin (as internal control group) were collected. Obtained histochemical data were analyzed by SPSS V.23 software. The expression of CD4+ marker in tumor microenvironment (TME) was compared by nonparametric Mann–Whitney and Kruskal–Wallis as well as Fisher’s exact tests. P < 0.05 was remarked statistically significant.

The low‑grade patients represented more CD4+ TIL that was statistically significant (P = 0.011). However, there was no statistically significant difference in CD4+TIL between various stages (P = 0.404), tumor size, and lymph node involvement (P > 0.05). Moreover, there was no significant relation between TIL infiltration, age, and tumor localization (P > 0.05), however CD4+ expression in women was more than men (P = 0.008).The CD4+T‑lymphocyte infiltration in TME was more significant than healthy surgical margin (P < 0.001). There was a statistically significant difference between healthy surgical margin and different grades and stages of OSCCs that lower grades demonstrated more CD4+ TIL infiltration (P < 0.001).

The CD4+ T‑lymphocytes may play important role in differentiation and maturity of epithelial cell, tumorigenesis, and progression of OSCC.

The aim of the study was to compare the root coverage percentage and other clinical outcomes in Millers Class I and Class II gingival recessions (GR) treated with modified coronally advanced flap (MCAF) combined with connective tissue graft (CTG) using macro and microsurgical approaches.

In this controlled clinical trial, a total of 32 Miller’s Class I and Class II GR defects were randomly assigned to the control and test groups (16 in each group). All the patients were treated with MCAF with CTG as the root coverage procedure. For the control and test groups, the procedure was performed using a macro and microsurgical approach, respectively. Clinical parameters were assessed at baseline and in 6th month. Wilcoxon signed–rank test was used to compare the values between baseline and 6 months. Statistical significance was set at P < 0.05. 1 week after surgery, wound healing index (WHI) and Visual Analog Scale (VAS) scores were recorded.

Intragroup comparisons revealed significant improvement in all the parameters in both the groups at 6 months. The proportion of root coverage achieved in the control and test groups was 78% and 86%, respectively. At 6 months, the root coverage percentage between the study groups showed no significant difference (P = 0.207). Intergroup analysis of WHI and VAS scores showed better healing and less postoperative pain in the microsurgical group compared to macrosurgical group (P < 0.05).

At 6 months, there were no significant differences in root coverage percentage or other clinical parameters between the groups based on whether a macro or microsurgical method was used. However, better wound healing, less pain, and discomfort were observed in the microsurgical group.

To overcome the drawbacks of sinus floor augmentation procedures newer surgical techniques to reduce sinus perforation such as crestal approach sinus kit (CAS) and piezosurgery, which are minimally invasive procedures enabling uncomplicated sinus elevation have evolved.The aim of the present study was to investigate the performance of CAS kit compared to piezosurgery during maxillary sinus membrane elevation.

A total of 40 subjects requiring maxillary sinus membrane augmentation for rehabilitation with implant prosthesis in posterior maxilla were included in the study. The current study was a prospective clinical trial where osteotomy and sinus elevation was done using CAS kit in Group 1 and piezosurgery in Group 2. Platelet‑rich fibrin was placed in osteotomy site and dental implants were inserted. Implant stability was evaluated at baseline and 3 months. Crestal bone loss was measured at 3, 6, and 12 months. Apical bone gain was measured at 6 and 12 months. Intragroup comparison of the study groups was done by Paired t‑test, ANOVA test, and Friedman test. Intergroup comparison was done by unpaired t‑test and Mann–Whitney U‑test. P < 0.05 was considered statistically significant.

Implant stability improved in both the groups, i.e., 79.2 ± 5.02 and 79 ± 5.31 in Group 1 and Group 2, respectively, at 3 months. Intergroup comparison showed no difference in all parameters; however, crestal bone loss was greater in piezosurgery group with a mean difference of 0.74 mm.

Both CAS and piezosurgery groups showed definitive improvement in all parameters. CAS group resulted in added benefits in terms of less crestal bone loss and intraoperative surgical time compared to piezosurgery group.

The aim of the study was to assess the opportunities and threats of e‑learning in dental schools and explore the experiences of dental faculty members in the coronavirus disease‑19 (COVID‑19) epidemic conditions.

The present study was a sequential exploratory mixed method study (quantitative‑qualitative). In the quantitative phase, a survey study was conducted to investigate the perspectives of faculty members regarding the opportunities and threats of e‑learning during the COVID‑19 epidemic. The data were analyzed by descriptive indicators (frequency, percentage, mean, and standard deviation) and analytical tests (t‑test and analysis of variance). In the qualitative phase, data were collected through semi‑structured interviews. In the qualitative phase, the inductive content analysis approach of Graneheim and Lundman was used to analyze the interviews.

In this study, 213 faculty members of dental schools of Iran participated; among whom 100 were men (46.9%) and 133 were women (53.1%). The results indicated the mean scores of the perspectives of faculty members regarding the opportunities and threats of e‑learning in dentistry (4.05 ± 0.49 out of 5). Experiences of the participants in the qualitative phase were explored in the theme of “ups and downs of e‑learning in dentistry” with three categories “unaccountability of e‑learning in dental education,” “challenges of human resource empowerment in the e‑learning process,” and “planned education.”

The majority of the faculty members agreed with the use of e‑learning in dental education and considered it as an opportunity. However, educational design for blended learning, creation of appropriate infrastructures, and empowerment of human resources as e‑teacher and e‑student were emphasized as key requirements for e‑learning development in dental schools.

Although glass‑ionomer cement (GIC) has many unique properties and advantages, it still lacks favorable mechanical properties. Cention N is a recent alkasite material with excellent mechanical properties. The purpose of this study was to compare the mechanical properties(fracture toughness [FT] and flexural strength [FS]) and acid buffer capability of an alkasite material to GIC.

In this in vitro study, a total of 60 samples were prepared using Cention N or GIC. Twenty specimens (n = 10) were prepared using beam‑shapedTeflon molds for FS, and twenty specimens (n = 10) were prepared with a similar mold with a notch for FT. These were evaluated on a universal testing machine using a three‑point bend test. Twenty (n = 10) disk‑shaped specimens were prepared for acid buffer capability. The samples were stored in distilled water for a week. This was followed by immersion in lactic acid with a pH of 4 for calculation of the materials acid buffering capacity at 30 and 60 min from exposure using a pH meter. The data obtained were tabulated and subjected to Kolmogorov–Smirnov test and Shapiro–Wilk test to assess the normal distribution and further analyzed using the Student’s t‑test to assess the level of significance, P < 0.05 was considered statistically significant.

The mean FT, FS, and acid buffer capability of Cention N were significantly higher than GIC at P < 0.05.

The present study surmised that Cention N exhibited higher FT, FS, and acid buffer capability than GIC.

The chemical bond between the metal and the porcelain component is likely to fail in metal‑porcelain restorations. This is due to the thick oxide layer that Cr–Co alloys create. This study aimed to investigate the effect of metal conditioner on controlling the oxide layer formed on the surface of the Sintron alloy and the strength of the metal–porcelain bond.

In this in vitro study, 33 samples were divided into three groups based on surface treatment (n = 11). In all three groups, an oxide layer was created. In the first group, Shofu metal conditioner, in the second group, metal conditioner of Creation, and in the third group, no metal conditioner was applied. All samples were then subjected to 3000 heat cycles between 5° and 55°C with a stop time of 5 s. The specimens were then placed in a universal testing machine for shear bond testing. A force was applied between the alloy and the porcelain by a 5 kN load cell at the speed of 1 mm/min until a fraction occurred. Intergroup comparison was made by the one‑way analysis of variance followed by the Tukey’s multiple comparisons test (α = 0.05).

The mean shear bond strength of the first group was 34.93 MPa and the mean shear bond strength of the second group was 31.37 MPa.The mean shear bond strength of the first and the second group was significantly higher than the third group (23.37 MPa) (PV < 0.001).

The use of metal conditioners between ceramill Sintron alloy and porcelain (Vita VMK MASTER) led to increasing the bond strength.