Microshear Bond Strength of Scotchbond Universal Adhesive to Primary and Permanent Dentin: A Six-Month in Vitro Study

Objectives:

This study aimed to assess the microshear bond strength (MSBS) of Scotchbond Universal adhesive, used in self-etch and etch-and-rinse modes, to primary and permanent dentin at 24 hours and six months.

Materials and Methods:

A total of 88 composite micro-cylinders were divided into eight groups (n=11) as follows: (A) Etch-and-rinse, 24 hours, primary dentin; (B) Self-etch, 24 hours, primary dentin; (C) Etch-and-rinse, six months, primary dentin; (D) Self-etch, six months, primary dentin; (E) Etch-and-rinse, 24 hours, permanent dentin; (F) Self-etch, 24 hours, permanent dentin; (G) Etch-and-rinse, six months, permanent dentin; (H) Self-etch, six months, permanent dentin. The MSBS was measured by a testing machine at a crosshead speed of 0.5 mm/minute. Data were analyzed using three-way analysis of variance (ANOVA).

Results:

The mean MSBS was 12.3±2.3 MPa in A, 18.8±4.1 MPa in B, 11.9±3.7 MPa in C, 16±2.9 MPa in D, 19.1±2.7 MPa in E, 22.8±4.1 MPa in F, 16.2±2.6 MPa in G, and 17.2±4.4 MPa in H. In the self-etch mode, the MSBS was significantly higher than that in the etch-and-rinse mode (P<0.001). The MSBS in permanent teeth was significantly higher than primary teeth (P<0.001). At six months, the MSBS significantly decreased in all groups (P<0.001).

Conclusion:

The micro-shear bond strength of Scotchbond Universal adhesive decreases over time and depends on the type of tooth and the mode of application of the adhesive.

Comparative effectiveness of Low Level Laser therapy and Transcutaneous Electric Nerve Stimulation on Temporomandibular Joint Disorders

Introduction: Temporomandibular joint disorders (TMDs) are the most common source of pain on the face. There are multiple etiologies, and several types of treatment have been reported. The use of non-invasive and reversible therapies in the treatment of such problems is recommended. The present study evaluated the effect of low-level laser (LLL) therapy and transcutaneous electric nerve stimulation (TENS) on TMDs. Methods: In this single-blind study, 40 patients with temporomandibular disorders were randomly divided into four groups: TENS (TENSTem dental), LLL (diode 810 nm CW), shamTENS, and sham-LLL. All subjects were examined and data on pain and tenderness in the temporomandibular joint (TMJ) and masticatory muscles (using the visual analogue scale) and mouth-opening (distance between incisal edges before feeling pain; mm) were collected before baseline (T1), after each session (T2-T5) and one month after the end of the sessions (T6)), and analyzed using repeated measure analysis of variance (ANOVA) and Bonferroni statistical tests. A P value < 0.05 was considered significant. Results: The decrease in pain (P=0.000), tenderness (P=0.000) and increase in mouth-opening ability (P=0.002) was greater in the TENS and LLL groups than in the placebo groups. At the one-month follow-up, significant decrease in pain and tenderness was recorded in the TENS and LLL groups (P=0.000). There was no significant differences between TENS and LLL and the placebo groups for maximum mouth-opening at the end of the study (P=0.692). Conclusion: Using TENS or LLL therapy can improve TMD symptoms at least for the short term. Although the effects of the placebo played a role in improving symptoms, their effects were less important.

The Effect of An Angiogenic Cytokine on Orthodontically Induced Inflammatory Root Resorption

Objective

Orthodontically induced inflammatory root resorption (OIIRR) is an undesirable sequel of tooth movement after sterile necrosis that takes place in periodontal ligament due to blockage of blood vessels following exertion of orthodontic force. This study sought to assess the effect of an angiogenic cytokine on OIIRR in rat model.

Materials and Methods

In this experimental animal study, 50 rats were randomly divided into 5 groups of 10 each: E10, E100 and E1000 receiving an injection of 10, 100 and 1000 ng of basic fibroblast growth factor (bFGF), respectively, positive control group (CP) receiving an orthodontic appliance and injection of phosphate buffered saline (PBS) and the negative control group (CN) receiving only the anesthetic agent. A nickel titanium coil spring was placed between the first molar and the incisor on the right side of maxilla. Twenty-one days later, the rats were sacrificed. Histopathological sections were made to assess the number and area of resorption lacunae, number of blood vessels, osteoclasts and Howship’s lacunae. Data were statistically analyzed using ANOVA and Tukey’s honest significant difference (HSD) test.

Results

Number of resorption lacunae and area of resorption lacunae in E1000 (0.97 ± 0.80 and 1. 27 ± 0.01×10^-3, respectively) were significantly lower than in CP (4.17 ± 0.90 and 2.77 ± 0.01×10-3, respectively, P=0.000). Number of blood vessels, osteoclasts and Howship’s lacunae were significantly higher in E1000 compared to CP (P<0.05).

Conclusion

Tooth movement as the outcome of bone remodeling is concomitant with the formation of sterile necrosis in the periodontal ligament following blocked blood supply. Thus, bFGF can significantly decrease the risk of root resorption by providing more oxygen and angiogenesis.

Effect of Ingested Liquids on Color Change of Composite Resins

OBJECTIVES

Color change of composite restorations is well known to dentists. However, the effect of commonly consumed drinks on discoloration of composite resins has yet to be determined. This study sought to assess the color change of a nanofilled (Premise) and a flowable composite resin (Premise flowable) following simulated consumption of tea, cola, iron drops and multivitamin syrup.

MATERIALS AND METHODS

Forty disk-shaped specimens (7 mm in diameter and 2 mm thick) were fabricated from each composite resin. The baseline color values were measured according to the CIE L*a*b* system using digital imaging. The specimens of each restorative material were randomly divided into five groups (eight each) according to the storage media namely tea, cola, iron drops, multivitamin syrup or distilled water (control). The specimens were immersed in staining solutions for three hours daily over a 40-day test period. Following this, the color change values (ΔE*) were calculated. For statistical analyses, the color differences were analyzed using two-way ANOVA and Tukey's test (P< 0.05).

RESULTS

There was no significant difference in ΔE* values between the two types of composite resins (P>0.05). In both composite materials, the difference among the solutions was not significant (P>0.05).

CONCLUSION

Under the tested experimental conditions, both restorative materials were susceptible to discoloration by all four staining solutions. The color change values were not related to the solution or the type of material used.

Effect of Rhus coriaria L. water extract on five common oral bacteria and bacterial biofilm formation on orthodontic wire

BACKGROUND AND OBJECTIVES

Recently, use of herbal medicine and plant extracts as a substitute for commercially available chemical drugs for control of infectious diseases such as dental caries and periodontal disease has become increasingly popular. The present study was aimed to evaluate the effect of Rhus coriaria L. water extract on five common oral bacteria and bacterial biofilm formation on orthodontic wire.

MATERIALS AND METHODS

For primary assessment of the antibacterial properties of Rhus coriaria L. water extract, the well-plate method in BHIA (Brain Heart Infusion Agar, Merck, Germany) medium was used Using macrodilution method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the extract against each microorganism were determined. The effect of Rhus coriaria L. on bacterial biofilm formation on orthodontic wire was assessed using viable cell count in biofilm medium (BM) containing 3% sucrose. In the final phase, after fixation of samples in alcohol and glutaraldehyde, samples were prepared for SEM (Scanning Electron Microscopy) analysis.

RESULTS

The diameter of the zone of growth inhibition was proportionate to the tested concentrations of the extract. The lowest MIC (0.390 mg/ml) and MBC (1.5 mg/ml ) of the Rhus coriaria L. were found to be against Streptococcus sobrinus ATCC 27607. Rhus coriaria L. water extract decreased bacterial biofilm formation on orthodontic wire at MIC and 1/8 of MIC by S. sanguinis ATCC 10556, S. sobrinus ATCC 27607, S. salivarius ATCC 9222, S. mutans ATCC 35608 and E. faecalis CIP 55142 by24.2%-43%, 68.5%-91.6%, 10.6%-79.1%, 22.2%-86.1% and 40.6%-76.4%, respectively.

CONCLUSION

Based on the results, Rhus coriaria L. water extract had significant antibacterial properties against five common oral bacteria and was able to inhibit bacterial biofilm formation on orthodontic wire. Further investigations are recommended for widespread clinical use of this extract.

Determination of rate and causes of wastage of blood and blood products in Iranian hospitals

Objective: The purpose of this study was to determine the rate and causes of wastage of blood and blood products (packed red cells, plasma, platelets, and cryoprecipitate) in Qazvin hospitals.

Materials and Methods: The study was conducted in all hospitals in Qazvin, including 5 teaching hospitals, 2 social welfare hospitals, 3 private hospitals, 1 charity hospital, and 1 military hospital. This descriptive study was based on available data from hospital blood banks in the province of Qazvin. The research instrument was a 2-part questionnaire. The first part was related to demographic characteristics of hospitals and the second part elicited information about blood and blood component wastage. The collected data were then analyzed using descriptive statistic methods and SPSS 11.5.

Results: Blood wastage may occur for a number of reasons, including time expiry, wasted imports, blood medically or surgically ordered but not used, stock time expired, hemolysis, or miscellaneous reasons. Data indicated that approximately 77.9% of wasted pack cell units were wasted for the reason of time expiry. Pack cell wastage in hospitals is reported to range from 1.93% to 30.7%. Wastage at all hospitals averaged 9.8% among 30.913 issued blood products. Overall blood and blood product (packed red cells, plasma, platelets, and cryoprecipitate) wastage was 3048 units and average total wastage per participant hospital for all blood groups was 254 units per year.

Conclusion: Blood transfusion is an essential part of patient care. The blood transfusion system has made significant advancements in areas such as donor management, storage of blood, cross-matching, rational use of blood, and distribution. In order to improve the standards of blood banks and the blood transfusion services in Iran, comprehensive standards have been formulated to ensure better quality control in collection, storage, testing, and distribution of blood and its components for the identified major factors affecting blood product wastage.

Effect of basic fibroblast growth factor on orthodontic tooth movement in rats

OBJECTIVE

Basic fibroblast growth factor (bFGF) is a cytokine involved in angiogenesis, tissue remodeling and stimulation of osteoblasts and osteoclasts. The present study assesses the effects of a local injection of bFGF on the rate of orthodontic tooth movement.

MATERIALS AND METHODS

: In this laboratory animal study, we randomly divided 50 rats into 5 groups of 10 rats each. Rats received 0.02 cc injections of the following doses of bFGF: group A (10 ng), group B (100 ng) and group C (1000 ng). Group D (positive control) received an orthodontic force and injection of 0.02 cc phosphate buffered saline whereas group E (negative control) received only the anesthetic drug. A nickel titanium spring was bonded to the right maxillary first molar and incisor. After 21 days, the rats were sacrificed and the distance between the first and second right molars was measured by a leaf gauge with 0.05 mm accuracy. ANOVA and Tukey's HSD statistical tests were used for data analysis.

RESULTS

The greatest mean value of orthodontic tooth movement was 0.7700 mm observed in group C followed by 0.6633 mm in group B, 0.5333 mm in group A, 0.2550 mm in group D and 0.0217 mm in group E. There was a significantly higher rate of tooth movement in the test groups compared to the control groups (p<0.05). Among the test groups, the rate of tooth movement in group C was significantly higher than group A (p<0.05). Weight changes after the intervention were not significant when compared to the baseline values, with the exception of group E (p>0.05).

CONCLUSION

The effect of bFGF on the rate of tooth movement was dose-dependent. Injection of 1000 ng bFGF in rats showed the most efficacy.