Dental Research Journal
Volume:16 Issue: 6, Nov-Dec 2019

Application of hemostatic agents can negatively affect the bond strength of adhesive systems to dental substrate. This study aimed to assess the effect of ferric sulfate on microshear bond strength of four total‑ and self‑etch adhesives to dentin after water storage.

In this in vitro study, 192 dentin slices with 2 mm thickness were made of 64 extracted sound human third molars. The samples were divided into 8 groups (n = 24) as follows: G1: Scotchbond Multi‑Purpose, G2: hemostatic agent + Scotchbond, G3: Adper Single Bond, G4: hemostatic agent + Adper, G5: Clearfil SE Bond, G6: hemostatic agent + Clearfil, G7: Single Bond Universal, and G8: hemostatic agent + Single Bond Universal. Composite cylinders with 0.7 mm diameter and 1 mm height were bonded to the surfaces. Each group was then divided into two subgroups (n = 12) for water storage for 24 h and 3 months. The microshear bond strength was then measured. Data were analyzed using the Shapiro–Wilk test, three‑way ANOVA, one‑way ANOVA, and Tukey’s test (P < 0.05).

Application of ferric sulfate decreased the bond strength of all bonding agents after both 24 h and 3 months of storage; but, this reduction was not statistically significant (P > 0.05). Single Bond Universal at 24 h showed the highest and Adper Single Bond at 3 months showed the lowest bond strength (P < 0.001).

Dentin contamination with hemostatic agents negatively affects the bond strength of total‑ and self‑etch adhesives.

This study was to assess and compare the marginal and internal fit of stainless steel crowns (SSCs) with those of preveneered SSCs and zirconia crowns using different luting cements.

In this in vitro study, 36 primary first molars were divided into three groups (n = 12) each prepared to receive different crowns (SSCs, preveneered SSCs, or zirconia crowns). Each group was further subgrouped (n = 4) according to the luting cement (resin cement, glass ionomer cement [GIC], or resin‑modified GIC [RMGIC]). After cementation, the teeth were sectioned in the buccolingual direction to assess the marginal and internal fit. The results were analyzed using ANOVA and Bonferroni statistical tests. The level of significance was set at P < 0.05.

Zirconia crowns, especially those cemented with resin cement, were associated with the lowest marginal and internal gap width. Regardless of the luting cement, no significant difference was observed between all three crowns tested in terms of marginal gap (P > 0.05); however, zirconia crowns cemented with resin cement had significantly lower internal gap than preveneered SSCs and SSCs cemented with resin cement. In addition, those cemented with RMGIC had significantly lower internal gap than preveneered SSCs cemented with that cement (P < 0.05).

Zirconia crowns cemented with resin cement were the most accurately fitted internally, while marginally, they were not significantly different from the rest of crown‑luting cement combinations tested.

Self‑disinfecting impression materials would reduce time and energy needed for impression disinfecting process in clinic. The aim of this study was to evaluate the antimicrobial effect of alginate mixed with nanosilver solution at a concentration of 500 ppm and 1000 ppm on common oral microorganisms and assess changes in working time, setting time, and surface detail reproduction.

In this in vitro study, three groups were assigned. The first group was alginate, the second group was alginate mixed with 500 ppm nanosilver, and the third group was alginate mixed with 1000 ppm nanosilver. Antimicrobial effect on Escherichia coli, Staphylococcus aureus, and Candida albicans was studied using direct contact test in each group (n = 10). Working time (n = 10), setting time (n = 10), and surface detail reproduction (n = 10) were evaluated separately using the ISO 21563 protocol. Descriptive tables were used to describe the data. Kruskal–Wallis test used to determine significant differences in the number of colonies was counted in antimicrobial test (α = 0.05).

No adverse effects observed in working time, setting time, and surface detail reproduction of alginate impressions. Alginate mixed with silver nanoparticles showed no inhibitory effect on S. aureus and C. albicans, but the number of E. coli colonies were counted in the group 1000 ppm was significantly lower than 500 ppm (P = 0.001).

Antimicrobial effect of alginate mixed with silver nanoparticles is not clinically indicated. Nevertheless, its physical features did not change significantly.

Calcium silicate cements in treatments such as revascularization and apexogenesis are adjacent to blood and pulp tissues. This study evaluated tooth discoloration after treatment with mineral trioxide aggregate (MTA), calcium‑enriched mixture (CEM) cement, and Biodentine® in the presence and absence of blood using spectrophotometric analysis.

In this experimental study, A total of 68 extracted permanent anterior teeth were prepared and randomly divided into two groups as follows: the sponge embedded in access cavities was saturated with fresh blood or normal saline using insulin syringe, and then each group was subdivided into the following three cement subgroups: MTA‑Angelus®, CEM cement, and Biodentine; these materials with a thickness of 3 mm were placed in the access cavity on the sponge. In the control group, the sponges were saturated in saline and blood in the absence of cements. Discoloration rate was measured by spectrophotometer within the following four intervals: after preparing the cavity and 1 day, 1 month, and 6 months after material placement. ANOVA and Tukey’s test were used to assess the effect of blood and materials and time on discoloration. (P < 0.05).

In general, discoloration rate is significantly higher in blood group than saline group (P < 0.05) and an increase in ∆ E is observed over time for the materials in all groups. In this study, discoloration rate in the presence and absence of blood in Biodentine group was lower, and this difference was statistically significant compared to that of MTA group (P < 0.05) but not significant compared to that of the CEM group.

This study indicated that Biodentine induces the lowest tooth discoloration in the presence and absence of blood, and its discoloration rate is significantly lower than that of MTA. Therefore, it can be suggested that Biodentine can be used more confidently for endodontic treatments with coronal blood contamination such as regeneration and cervical perforation repair in esthetic zone of teeth.

Artifacts, artificial structures at microscopic section, may lead to incorrect diagnosis and wrong treatment of a pathological entity. The aim of this study was to evaluate the frequency of various artifacts found in oral and maxillofacial histopathologic sections.

In this cross‑sectional study, the specimens included the histopathologic sections along with their diagnosis that were collected from the archive of Isfahan Oral and Maxillofacial Pathology Department using systematic sampling method over a 10‑year period. These histopathologic sections were studied by two oral pathologists and an expert laboratory technician for the presence or absence of various artifacts, and the specimens from inside and outside the university were compared. The data were analyzed by SPSS software using independent t‑test at significance level  = 0.05.

From among 237 specimens studied, 235 specimens (99.15%) had artifacts and two specimens had no artifacts. From among 21 different types of artifacts, folding (n = 158) and throughout cleft (n = 149) artifacts had the highest frequency. There was no significant difference between the specimens of inside and outside the university (P = 0.125).

The results of this study showed a high number of artifacts in the histopathologic sections, the most frequent artifact being reported for the folding artifact. It seems adequate control of specimens and preventing technical errors can reduce the number of artifacts.

Despite many advantages of lasers and reduction of the risk of surface bonding errors with newer self‑etch systems, they have not been thoroughly researched. This study was done to evaluate the effect of Er:YAG laser cavity preparation on the microtensile bond strength of 2‑hydroxyethyl methacrylate (HEMA)‑rich and HEMA‑free one‑step self‑etch adhesive systems.

In this in vitro study, eighty freshly extracted human premolars were collected. Cavities were prepared in 40 teeth with carbide bur (Group 1) and in other 40 teeth with Er:YAG LASER (490 mJ and 15 Hz) (Group 2). Subgroups of twenty teeth each were made according to the adhesive systems used. After placement of restoration, the mean values of the bond strength were calculated using universal testing machine. Data were then tabulated and analyzed using descriptive statistics (Significant at P < 0.05).

The overall microtensile bonding strength was higher when the cavities were prepared with bur compared to those with Er:YAG laser. Mean bond strengths of single‑bottle self‑etching seventh‑generation dentin bonding agents to bur‑prepared cavities were higher than those to laser‑prepared cavities irrespective of the adhesive system (P = 0.01). No statistically significant difference was observed between HEMA‑free and HEMA‑rich self‑etch adhesive systems.

The effect of Er:YAG laser for cavity preparation did not show improved performance when evaluated using microtensile bond strength with seventh‑generation bonding agents, Adper Easy One and G‑Bond. More studies are required to assess the effect of lasers.

This study was conducted to determine the effects of sodium hexametaphosphate (SHMP) combined with other remineralizing agents on the staining and microhardness of early enamel caries.

in This in vitro study The enamel buccal surfaces of 70 bovine incisors were classified into seven study groups (n = 10). Remineralizing agents were employed alone and in combination with SHMP in different groups, including: (1) 8% SHMP, (2) 2% sodium fluoride, (3) 2% sodium fluoride + SHMP, (4) Remin Pro®, (5) Remin Pro®+SHMP, (6) MI Paste Plus, and (7) MI Paste Plus + SHMP. A modified pH‑cycling technique was used to reconstruct the dynamics of caries. Colorimetric and microhardness analyses were conducted before demineralization (T1), after caries formation (T2), and after the remineralizing treatment (T3). The data were analyzed by the one‑way analysis of variance and the repeated measurement analysis (P > 0.05).

After remineralizing cycles, the experimental groups treated with either SHMP alone or in combination with other materials showed less significant changes in the three variables of color (∆a, ∆b, and ∆L) and the overall color change (∆E). The enamel caries treated with Remin Pro® presented the highest color change, while Remin Pro®+ SHMP resulted in the least changes. The mean value of microhardness after remineralization improved significantly in all groups, except in the MI Paste Plus + SHMP group that showed the lowest value. In contrast, the highest microhardness value was recorded for Remin Pro®, being comparable to that of the sound teeth (P > 0.05).

SHMP, either alone or combined with remineralizing agents, created the least staining. Remineralizing materials alone showed higher surface hardness, while sodium fluoride alone showed higher surface hardness when combined with SHMP.

The aim of the study was to evaluate the accuracy of iPex and Vdw gold apex locators in detecting simulated root perforations in curved canals in the presence of 3% sodium hypochlorite (NaOCl) and 2% chlorhexidine (CHX).

In this comparative in vitro study Twenty mandibular molars with curved mesial roots were selected and perforation was made in the danger zone 4 mm from the furcation area. The actual length of the perforation site was measured using stereomicroscope software using a #15 K file, following which the teeth were embedded in alginate molds. The perforation site was electronically measured using two apex locators, iPex and Vdw gold in dry condition and in the presence of 3% NaOCl and 2% CHX. The values obtained were compared using the Friedman and Wilcoxon signed‑rank test with level of statistical significance set at P ≤ 0.05.

In dry condition, Vdw gold showed near accurate values, i.e., 0.25 mm from the manual value whereas iPex showed a significant difference (P < 0.05) of 0.76 mm from the manual value. In the presence of 3% NaOCl, both the apex locators showed a significant difference (P < 0.05) from the manual value with iPex showing a difference of 0.70 mm and Vdw gold showing a difference of 0.74 mm. The most accurate values were determined by both the apex locators in the presence of 2% CHX with iPex showing a deviation of 0.13 mm and Vdw gold showing a deviation of 0.39 mm from the manual.

In dry condition, Vdw group showed better results than iPex in determining the length of the root perforation. In wet condition, in the presence of 2% CHX, both the apex locators accurately measured the perforation site, whereas in the presence of 3% NaOCl, both the apex locators showed a significant difference (P < 0.05) from the manual value in detecting the root perforation.

Chronic periodontitis (CP) is one of the most prevalent diseases of the oral cavity with various biological and behavioral risk factors. We aimed to evaluate the association between the salivary cortisol level (SCL) of unstimulated saliva and CP in patients referred to Isfahan Dental Faculty.

In this analytic cross‑sectional study, 90 patients were selected based on the presence of periodontitis and were divided into two groups: with periodontitis and without periodontitis (n = 45). First, by evaluating the level of anxiety with Spielberger State‑Trait Anxiety Inventory questionnaire, each group was divided into three subgroups, each containing 15 persons. To measure the SCL in all subgroups by the enzyme‑linked immunosorbent assay method, saliva samples were collected with unstimulated spitting method between 9 and 11 AM. Periodontal evaluation was done using the mean probing depth (PD), plaque index, and bleeding on probing. The obtained data were analyzed using SPSS software (version 20, IBM Corp., Armonk, N.Y., USA) and analysis of variance, independent t‑test, Chi‑square, Mann–Whitney, Spearman correlation, and Pearson correlation coefficient tests (α = 0.05).

The mean level of salivary cortisol (P = 0.048) and PD (P = 0.009) in patients with periodontitis was significantly higher than those without periodontitis. There was a direct and meaningful correlation between PD and SCL (P < 0.001, r = 0.363). In both groups of participants with (P < 0.001) and without periodontitis (P < 0.001), the mean SCL in patients with high anxiety was significantly more than patients with medium and low anxiety.

Our results showed that there is an increased level of salivary cortisol (as anxiety index) in patients with CP. Therefore, it seems that the probability of the occurrence of periodontitis is higher in those with increased cortisol level.

Prefabricated band and loops require only one appointment, are quickly placed in a session, and do not require laboratory work; thus, they need less time and cost. The aim of this study was to evaluate the survival rate of prefabricated band and loops in space maintenance of primary teeth and compare them with conventional band and loops.

In this prospective clinical trial study 4–9‑year‑old patients, who met the requirements of the present study, were divided into two groups. The first group conventional band and loops and the second group prefabricated band and loops were placed. The patients were evaluated for cement dissolving. Failure of soldering (SF), breakdown, and deformation of each component of the band and loops, survival rate, and gingival health at the 1st, 3rd, 6th, and 9th‑month Wilcoxon test, Fisher’s exact test, Mann–Whitney test, Friedman test, and Kaplan–Meier test. Was used The level of statistical significance was set at P ≤ 0.05.

The two groups were not significantly different at the 1st, 3rd, 6th, and 9th‑month recalls in cement solution, SF, breakdown, and deformation of each component of the band and loops. The survival rate of the conventional and prefabricated band and loops was 92% in the 9 months, and no significant difference was witnessed in survival rates between the two groups. The prevalence of gingivitis in prefabricated band and loops and conventional band and loops in the 9th month was statistically insignificant (P = 0.03).

There is a similar success rate for the conventional and prefabricated band and loops.

A precise transfer of the position of an implant to the working cast is particularly important to achieve an optimal fit of the final restoration. Different variables affect the accuracy of implant impression. The purpose of the present study is to compare the accuracy of open‑tray and snap‑on impression techniques in implants with different angulations.

In this experimental study: A reference acrylic resin model of the mandible was fabricated. Four implants were positioned with the angles of 0°, 10°, 15°, and 25° in the model. Ten impressions were prepared with open‑tray technique and ten impressions were made using snap‑on technique. All impressions were made from vinyl polysiloxane impression material. Linear (Δx, Δy, and Δr) and angular displacements (Δθ) of implants were evaluated using a coordinate measuring machine. Measured data were then analyzed using two‑way analysis of variance and Tukey’s test (α = 0.05).

The results showed that the accuracy of open‑tray impression technique is significantly different from snap‑on technique in Δx (P = 0.003), Δy (P = 0.000), Δr (P = 0.000), and Δθ (P = 0.000). Implants with 25° angulation are significantly less accurate than 0°, 10°, and 15° implants in Δx, Δy, Δr, and Δθ. Fifteen‑degree implants are less accurate than 0° and 10° ones in Δθ.

Regarding the findings of this study, it can be concluded that snap‑on technique is less accurate than open‑tray technique, and the accuracy of 25° implant is less than that of 0°, 10°, and 15° implants.

Bone formation in small deposits following the loss of part of the mandible has often been reported in the literature, but the long‑term follow‑up reports of bone regeneration extending over the mandible are rare. Even rarer, are reports on the behavior of such new bone in terms of facial development, over a long period and the effect of load on it. A unique case of bone regeneration after resection of a large portion of the mandible in a 9‑year‑old male patient with myxofibrosarcoma in the body of the mandible is presented here. Intermaxillary fixation and insertion of reconstruction plate after resection without continuity defect were employed. Spontaneous bone regeneration was noted 8 weeks after surgery, and the resected portion of the mandible was regenerated when the patient was seen again 7 years later. Mandibular growth was not significantly affected and almost 7 years after his treatment, without relapsing of pathologic condition, the shape of the mandible is satisfactory without any evidence of bone resorption.