Dental Research Journal
Volume:18 Issue: 9, Oct 2021

There is no clinical study on ceramic self‑ligating brackets (SLBs). Therefore, this preliminary study was conducted for the first time to address its effects.

This split‑mouth randomized trial was performed on 32 quadrants in 16 orthodontic patients needing extraction of maxillary premolars and distalization of canines. In each blinded patient, right/left sides were randomized into control (ceramic bracket) and experimental (ceramic SLB) groups. Dental stone models were taken before canine retraction and 3 months into retraction. Models were digitized as three‑dimensional models. Changes were measured on superimposed models. Groups were compared using Wilcoxon signed‑rank test (α = 0.05, β = 0.1).

Both bracket types caused significant changes after 3 months in terms of all assessed clinical outcomes (P ≤ 0.002). Compared to conventional ceramic brackets (control), ceramic SLBs reduced retraction rate (P = 0.001), canine rotation (P = 0.001), canine tipping (P = 0.002), and arch expansion at the canine site (P = 0.003). However, the extents of anchorage loss (P = 0.796) and arch constriction in the premolar area (P = 0.605) were not statistically different between the bracket types.

Compared to conventional metal‑lined ceramic brackets, active ceramic SLB can increase the duration of canine distalization, while reducing canine rotation and tipping (inducing more bodily movements). The loss of anchorage with ceramic SLB was similar to that of conventional ceramic bracket after 3 months of treatment (considering the lower rate of SLB canine retraction during that time). Both brackets similarly constricted the arch at the premolar site. In the canine area, they expanded the arch, with the SLB causing smaller extents of expansion.

The tissue engineering has recently shown a significant progress in the fields of membranes and biosynthetic materials. Advanced platelet‑rich fibrin (A‑PRF) contains functional molecules that have newly shown great interest in regenerative therapies. The purpose of this study was to evaluate the effect of A‑PRF on the adhesion of gingival fibroblast cells and osteosarcoma cells to different membranes.

In this experimental in vitro study, three collagen, alloderm, and mucograft membranes were studied, which were cut into four 5 mm × 5 mm pieces and placed in the bottom of a 24‑well culture medium. One milliliter of A‑PRF was added to two wells from each group and the other two wells remained without A‑PRF. The gingival fibroblasts and osteosarcoma cells were individually added to each well. The cell adhesion was studied using an electron microscope after 24 h. The data were analyzed by independent t‑test, one‑way analysis of variance, and least significant difference test.

In the presence of A‑PRF, there was a significant higher osteoblast adhesion to collagen membrane compared to alloderm and mucograft membranes (P < 0.001). In the absence of A‑PRF, adhesion of osteoblasts to collagen membrane was significantly higher than alloderm and mucograft (P = 0.019). Moreover, in the presence of A‑PRF, fibroblast adhesion to collagen membrane was significantly higher than alloderm and mucograft membranes (P < 0.001). Furthermore, in the absence of A‑PRF, no significant difference was found among the study groups (P = 0.830).

A‑PRF was effective on fibroblast adhesion to the collagen membrane, which is similar to its absence. A‑PRF was also found to be very effective on the adhesion of fibroblast cells to the collagen membrane, and in its absence, even less adhesion was observed compared to the other membranes. The presence or absence of A‑PRF showed no significant differences in both cells’ adhesion for alloderm and mucograft membranes.

The purpose of this study was conducted to evaluate the knowledge, attitude, and practice of intensive care unit (ICU) nurses about oral and dental care in hospitalized patients.

In this descriptive‑analytic study, the statistical population included 214 nurses working in the ICU of the affiliated hospitals of Isfahan University in 1394. The level of knowledge, attitude, and practice of ICU nurses was assessed using questionnaires whose justifiability and stability were verified at the beginning of the study with a pilot study. Data were entered into SPSS software and tested by t‑test, Spearman, one‑way variance, and least significant difference test. The significance level was < 0.05.

The data of this study showed that the score of knowledge and performance in male nurses was significantly different from female nurses. There was a significant relationship between nurse’s education and their knowledge score (P < 0.001). Furthermore, the performance score of nurses working in different parts was different too (P < 0.001).

The findings showed that the knowledge and performance of female nurses about oral care were higher than men, but the attitude of the two sexes is almost the same. Nurses with lower educational degree had less knowledge, but their attitude and performance did not differ. The performance score of nurses working in ICU was different, but they had similar knowledge and attitudes.

Dental scanners play a critical role in computer‑aided design/computer‑aided manufacturing technology. This study aimed to compare the accuracy (precision and trueness) of eight dental scanners for dental bridge scanning.

In this in‑vitro experimental study, a typodont model with a missing maxillary right first molar was prepared for a 3‑unit fixed partial denture. Each scanner (Sirona inEos inLab, Sirona X5, Dentium, Imes icore 350I I3D, Amann Girrbach map 100, 3Shape D100, 3Shape E3) performed seven scans of the typodont, and the data were analyzed using 3D‑Tool software. The abutment length, abutment width, arch length, and interdental distance were measured. To assess the accuracy of each scanner, trueness was evaluated by superimposing the scanned data on true values obtained by the 3shape Triosscanner as the reference. Precision was evaluated by superimposing a pair of data sets obtained from the same scanner. Precision and trueness of the scanners were compared using the one‑way ANOVA followed by the post‑hoc Tukey’s HSD test and one‑sample t‑test (P<0.05 was considerer significant).

The precision of scanners ranged from 14 μm (3Shape Trios) to 45 μm (Imes icore 350i), whereas the trueness ranged from 38 μm (3Shape d700) to 71 μm (Sirona X5).

The reported trueness values for 3Shape Trios, Sirona inEos inLab, Sirona x5, Dentium, Imes icore350i, Amann Girrbach, 3Shape d700, and 3Shape e3 were 63, 45, 71, 67, 70, 53, 38, and 42 μm, respectively, whereas the precision values were 14, 29, 44, 34, 45, 44, 30 and 28 μm, respectively.

This study aimed to compare the continuous rotation and reciprocating movements of rotary files in achieving apical patency in root canal retreatment.

This invitro, experimental study evaluated 64 extracted mandibular molars. The teeth were prepared up to F3 with ProTaper Universal and obturated using lateral compaction technique. The teeth were divided into four groups (n = 16) based on the mesiobuccal canal curvature (Schneider’s method) and type of rotational movement. Groups 1 and 2 included straight canal teeth retreated with WaveOne Gold and ProTaper Universal Retreatment system, respectively. Groups 3 and 4 included teeth with moderately curved root canals retreated with WaveOne Gold and ProTaper Universal, respectively. Apical patency was ensured by observing the tip of a hand K‑file at the apical foramen. Data were analyzed using the Fisher’s exact test. P < 0.05 was considered statistically significant.

Apical patency was successfully achieved in all 16 teeth in group 1 (100%) and 15 teeth in group 2 (93.75%). No significant difference was noted between continuous rotation and reciprocating movements in straight canals (P = 1.00). Apical patency was successfully achieved in 15 teeth in group 3 (93.75%) and 12 teeth in group 4 (75%). No significant difference was noted between continuous rotation and reciprocating movements in moderately curved canals either (P = 0.333).

Both continuous rotation and reciprocating movements are equally effective in achieving apical patency in straight or moderately curved mesiobuccal canal of mandibular molars

Although missing tooth is not life‑threatening, it affects the quality of daily life. Stem cells have emerged as an important player in the generation and maintenance of many tissues. The role of scaffolds has changed from a passive carrier to a bioactive matrix, which can be used to induce cellular behavior. The aim of this study was to determine the possibility of regeneration of dentin‑pulp complex with dental pulp stem cells (DPSCs) in an animal model.

In this animal study after extraction of DPSCs and cultivation, 10 types of scaffolds were made by using platelet‑rich plasma (PRP), cancellous bone, and collagen pad. They were inserted in different parts of the dog’s mouth. After the 4th month, the area was operated, and the scaffolds were removed.

Microscopic examination revealed no sign of cell differentiation and formation of new structures in those models which used collagen scaffolds. However, the dentin‑pulp complex emerged in models that the combination of bone scaffolds and PRP or stem cells was used.

Using bone scaffolds in combination with PRP or DPSCs to regenerate dentin‑pulp complex in dog helped odontoblastic and pulpal differentiation as well as the formation of predentin and tubular dentin.

The repair of composite restorations is considered as a conservative treatment for avoiding the risk of pulp injury, the enlargement of cavity preparation, and excess removal of sound dental structure. The aim of this study was to evaluate the effect of silane‑containing adhesives on immediate and delayed shear bond strength (SBS) of repaired composite restorations.

In this in vitro study, 132 discs of Z350 composite were fabricated and divided into fresh (10 min water storage) and aged (6‑month water storage + 2000 thermal cycling). All composite surfaces were roughened and etched, and each group was divided equally into six subgroups: 1 (Single Bond 2), 2 (Single Bond Universal), 3 (Clearfil Universal Bond), 4 (silane + Single Bond 2), 5 (silane + Single Bond Universal), and 6 (silane + Clearfil Universal Bond). The specimens were restored with the same composite, thermocycled, and tested for SBS in a universal testing machine. Data were analyzed using one‑ and two‑way ANOVA, t‑test, and posthoc Tukey’s tests.P < 0.05 was set as the level of significant.

The highest and lowest SBS (in both fresh and aged groups) were related to Single Bond 2 with silane and Clearfil Universal Bond with silane, respectively. The delayed SBS of Single Bond 2 was significantly higher than universal adhesives (in both with and without silane application) (P < 0.05). Silane had no significant effect on the repair bond strength of Single Bond 2 and Single Bond Universal (P > 0.05), while silane application significantly decreased the delayed SBS of Clearfil Universal Bond.

The SBS of Single Bond 2 was significantly better than two other universal adhesives. The SBS of Single Bond Universal was not affected by silane application, while silane had a negative effect on delayed SBS of Clearfil Universal Bond.

Oral squamous cell carcinoma (OSCC) is the sixth common cancer in the world and 90% of oral malignant tumors. The aim of this study was the investigation of changes in some metabolic elements of OSCC patients’ serum.

In this study, international databases such as PubMed, Science Direct, Scopus, Web of Science, and National (Magiran, IranMedex) were searched from 1980 to 2019. To analyze the data, a random‑effects model was used to combine the differences in the mean of studies in STATA Software (version 12).

A total of 724 articles were found with initial searching that 474 duplicate articles, 228 articles were excluded by reviewing the title and abstracts, and 17 articles were excluded from the study due to lack of inclusion criteria. Finally, five articles entered the meta‑analysis phase. The mean difference value for zinc concentration of blood serum was 2.01 (95% confidence interval (CI): 0.36–3.66) and for copper was 1.04 (95% CI: 0.01–2.07). In both populations, the heterogeneity was found between studies (I2 = 97.4, P < 0.001).

Probably higher serum levels of copper and zinc could be one way to help to do a primary screening of OSCC in suspected patients.

This study compared microleakage of Class II cavities restored using bonded‑base and bulk‑fill techniques with different bases.

In this in vitro study, in 60 extracted human molars, standardized (4 mm × 2 mm × 8 mm) Class II cavities were prepared, such that the gingival floor was located 1 mm below the CEJ. The teeth were randomly divided into five groups and filled with: (1) Fuji II LC + x‑tra fil, (2) Ionoseal + x‑tra fil, (3) x‑tra base + x‑tra fil, (4) Grandio Flow + x‑tra fil, and (5) x‑tra fil only [control group]; in open‑sandwich technique, the base thickness was 1 mm. The bases were coated all gingival floor. Except for the first group, where dentin conditioner was used, the Clearfil SE bond was applied before application of the bases and restorative materials as a bonding agent. After 500 thermocycles between 5°C and 55°C, the specimens were immersed in 0.5% basic fuchsine solution for 24 h. The restored teeth were sectioned, and the dye penetration in gingival floor was observed by a stereomicroscope at ×32. The data were analyzed using Kruskal–Wallis and Mann–Whitney tests in SPSS software. The significance was determined at 0.05 confidence interval.

The statistical analysis revealed a significant difference in microleakage among the study groups (P < 0.001). The Ionoseal group followed by the control group (x‑tra fil composite) had the greatest microleakage. Except for the Ionoseal group, all other groups had significantly less microleakage than the control group.

The use of bonded‑base techniques could reduce microleakage, including those in bulk‑fill composite restorations.

There are a limited number of studies about the effects of microbial aging on the mechanical properties of restorative materials. Therefore, this study aimed to evaluate the effect of simulated aging with Streptococcus mutans on the flexural strength of different resin‑based materials.

This experimental study was performed on the blocks of different types of restorative materials including composite resin, giomer, and a resin‑modified glass ionomer (RMGI). Moreover, three types of aging, such as 30‑day storage in distilled water, S. mutans, and germ‑free culture medium, were used in this study. The three‑point bending flexural strength of the specimens before and after aging was measured according to the International Organization for Standardization‑4049 standard. Data were analyzed by two‑way ANOVA and post hoc Tukey’s tests. A P < 0.05 was considered statistically significant.

Results showed that the 30‑day aging with the S. mutans significantly reduced the flexural strength of all three types of materials (P = 0.00). In all restorative materials, storage in a bacteria‑free culture medium acted the same as distilled water, and there was no significant difference between these two solutions in terms of the flexural strength of the material, compared to the before‑aging strength (P > 0.05). Furthermore, no significant difference was observed between S. mutans‑based aging and distilled water aging regarding RMGI (P = 0.75).

It can be concluded that aging by S. mutans reduced the flexural strength in all three restorative materials