The Association between Dietary Inflammatory Index and Aging Biomarkers/Conditions: A Systematic Review and Dose-response Meta-analysis

OBJECTIVES

We performed a current study to examine the association between dietary inflammatory index (DII) score and older age-related muscle conditions, including sarcopenia, low muscle mass, low muscle strength, frailty, and/or disability.

DESIGN

Systematic review and dose-response meta-analysis.

SETTING

A systematic literature search was performed using Scopus, PubMed/MEDLINE, and ISI Web of Science without limitation until October 04, 2022. Relative risk (RR) and 95% confidence interval (CI) were pooled by applying a random-effects model, while validated methods examined assess quality and publication bias via Newcastle-Ottawa Scale, Egger's regression asymmetry, and Begg's rank correlation tests respectively. A dose-response meta-analysis was conducted to estimate the RRs per 1-unit increment in DII scores.

PARTICIPANTS

Adults (≥18 years).

MEASURES

The risk of older age-related muscle conditions (sarcopenia, low muscle mass, low muscle strength, frailty, and/or disability).

RESULTS

Data were available from 19 studies with 68079 participants. Results revealed that a higher DII score was significantly related to an increased risk of sarcopenia (RR=1.50; 95% CI: 1.26, 1.79; I2=53.3%; p<0.001; n=10; sample size =43097), low muscle strength (RR=1.47; 95% CI: 1.24, 1.74; I2=6.6%; p<0.001; n=4; sample size =9339), frailty (RR=1.61; 95% CI: 1.41, 1.84; I2=0.0%; p<0.001; study=5; participant=3882) and disability (RR=1.41; 95% CI: 1.16, 1.72; I2=58.4%; p=0.001; n=5; sample size =13760), but not low muscle mass (RR=1.24; 95% CI: 0.98, 1.56; I2=49.3%; p=0.069; n=4; sample size =11222). Additionally, results of the linear dose-response indicated that an increase of one point in the DII score was related to a 14% higher risk of sarcopenia, 6% higher risk of low muscle mass, 7% higher risk of low muscle strength, and a 7% higher risk of disability in adults. Non-linear dose-response relationships also revealed a positive linear association between the DII score and the risk of sarcopenia (Pnonlinearity = 0.097, Pdose-response<0.001), frailty (Pnonlinearity = 0.844, Pdose-response=0.010) and disability (Pnonlinearity = 0.596, Pdose-response=0.007).

CONCLUSION

Adherence to a pro-inflammatory diet was significantly associated with a higher risk of sarcopenia and other age-associated adverse effects such as low muscle strength, disability, and frailty. These results indicate a necessity to prioritize the reduction of pro-inflammatory diets to help promote overall older age-related muscle conditions.

Muscle thickness and pennation angle in overweight persons with moderate haemophilia A after resistance and combined training: A randomized controlled trial

INTRODUCTION

Muscular atrophy and overweightness develop arthropathy in persons with haemophilia (PWH), and exercise increases their muscle strength and decreases their body weight. Musculoskeletal ultrasonography may be a non-invasive, safe, valid, and reliable tool to investigate muscle thickness (MT) and pennation angle (PA) after exercise training.

OBJECTIVES

The present study was conducted to evaluate the effects of 6 weeks of resistance training (RT) and combined resistance and aerobic training (CT) on MT and PA in overweight persons with moderate haemophilia A.

MATERIALS AND METHODS

Forty-two persons with moderate haemophilia A with a mean age of 35-55 years and a BMI of 25-30 kg/m² were randomly assigned to three groups of 14, namely RT, CT, and control. The RT group performed 40 minutes of RT, and the CT group performed 20 min of RT and 20 min of aerobic training. The PA and MT of the biceps brachii (BB), triceps brachii (TB), vastus medialis (VM), vastus lateralis (VL), and medial gastrocnemius (MG) were measured before and after the intervention using B-mode ultrasonography.

RESULTS

Significant increases were observed in the MT of VM, VL, MG, BB, and TB and PA of VM, VL, and MG in the RT and CT groups compared to the control group (p < .001). No significant differences were observed between the intervention groups.

CONCLUSION

Both RT and CT were effective in enhancing MT and PA in overweight persons with moderate haemophilia A.

Controlled temperature-mediated curcumin release from magneto-thermal nanocarriers to kill bone tumors

Systemic chemotherapy has lost its position to treat cancer over the past years mainly due to drug resistance, side effects, and limited survival ratio. Among a plethora of local drug delivery systems to solve this issue, the combinatorial strategy of chemo-hyperthermia has recently received attention. Herein we developed a magneto-thermal nanocarrier consisted of superparamagnetic iron oxide nanoparticles (SPIONs) coated by a blend formulation of a three-block copolymer Pluronic F127 and F68 on the oleic acid (OA) in which Curcumin as a natural and chemical anti-cancer agent was loaded. The subsequent nanocarrier SPION@OA-F127/F68-Cur was designed with a controlled gelation temperature of the shell, which could consequently control the release of curcumin. The release was systematically studied as a function of temperature and pH, via response surface methodology (RSM). The bone tumor killing efficacy of the released curcumin from the carrier in combination with the hyperthermia was studied on MG-63 osteosarcoma cells through Alamar blue assay, live-dead staining and apoptosis caspase 3/7 activation kit. It was found that the shrinkage of the F127/F68 layer stimulated by elevated temperature in an alternative magnetic field caused the curcumin release. Although the maximum release concentration and cell death took place at 45 °C, treatment at 41 °C was chosen as the optimum condition due to considerable cell apoptosis and lower side effects of mild hyperthermia. The cell metabolic activity results confirmed the synergistic effects of curcumin and hyperthermia in killing MG-63 osteosarcoma cells.

Factors Influencing Malaysian Men's Perceptions of Gender Equity in Family Planning

INTRODUCTION

Various factors influence men's perceptions regarding gender equity in family planning (FP). Identifying these factors can contribute to a deeper understanding of the roles that men play in family planning and ultimately leads to women's reproductive health outcomes.

OBJECTIVES

This paper aims to investigate factors influencing Malaysian men's perceptions of gender equity in family planning. To achieve this, the effects of sociodemographic characteristics (age, education, and marital status), masculine traits, and attitudes towards domestic violence are investigated.

METHODOLOGY

This is a cross-sectional study undertaken by administrating questionnaires to a sample of 168 men in Malaysia. The data are analyzed by applying partial least squares-structural equation modeling (PLS-SEM) and by using WarpPLS 6.0.

RESULTS

The results confirmed the significant effects of masculine traits and attitudes supporting domestic violence on perceived gender equity in family planning. In other words, the results showed that men's masculine traits and attitudes supporting domestic violence negatively influenced gender equity in family planning. The hypothesized effects of sociodemographic characteristics on perceived gender equity in family planning could not be verified.

CONCLUSIONS

This study suggests some practical implications for local authorities to implement interventions that take a gender transformative approach to reduce men's masculine traits and improve their attitudes towards domestic violence to enhance gender equity in family planning.

Physical Properties of Nanohybrid and Microhybrid Resin Composites Subjected to an Acidic Environment: A Laboratory Study

BACKGROUND

This study investigated the hardness and color stability of five resin composites subjected to different polishing methods following immersion in distilled water or lactic acid for up to three months.

METHODS AND MATERIALS

Three nanohybrid, Paradigm (3M ESPE), Estelite Sigma Quick (Tokuyama), Ice (SDI), and two microhybrid, Filtek P60 and Filtek Z250, composites were examined. Disc-shaped specimens (10×1.5 mm) were prepared and immersed in distilled water for 24 hours then polished using either silicon carbide paper, the Shofu polishing system or were left unpolished (control). The CIE values and microhardness were determined using a spectrophotometer and digital Vickers hardness tester, respectively (n=10) after one, 45, and 90 days of storage in distilled water or lactic acid. Data were analyzed using analysis of variance, Tukey test, and Pearson correlation coefficient.

RESULTS

Ice exhibited the greatest color change, yet Paradigm and Filtek P60 demonstrated the least. Overall, discoloration of tested materials was multifactorial and the effect of storage media depended on the material, polishing method and time interval. The greatest hardness was obtained for Paradigm and the lowest for Estelite. Hardness was found to be significantly higher in lactic acid after 45 days (p=0.014) and even higher after 90 days (p<0.001) compared with distilled water.

CONCLUSIONS

An acidic environment did not adversely affect color stability or microhardness of the resin composites. There was a significantly mild reverse correlation between hardness and color change in both storage media.

The Effects of Concurrent Training Order on Satellite Cell-Related Markers, Body Composition, Muscular and Cardiorespiratory Fitness in Older Men with Sarcopenia

OBJECTIVES

Concurrent Training (CT) is described as a combination of resistance training (RT) and endurance training (ET) in a periodized program to maximize all aspects of physical performance. To date, effects of CT order on muscular and cardiorespiratory fitness adaptations are controversial. Owing to the age-related decrement in satellite cells (SC) which are critical for fiber repair, conservation, muscle hypertrophy as well as cardiorespiratory fitness, the present study examined the response of SC related markers to CT order in older sarcopenic men.

PARTICIPANTS

Thirty older men (age= 64.3 ± 3.5 years) were randomly assigned into one of 3 groups, ET followed by RT (E+R; n=10), RT followed by ET (R+E; n= 10) or a control (C; n=10).

INTERVENTION

The training protocol consisted of 3 exercise sessions per week for 8 weeks. Blood samples were obtained at baseline and 48 hours after the final training session.

RESULTS

Weight, skeletal muscle mass, lower and upper body power, maximal oxygen consumption (VO2max), Paired Box 7 (Pax7), and Myogenic factor 5 (Myf5) significantly increased, while were percent body fat significantly decreased following E+R and R+E compared to C. Importantly, the improvement in skeletal muscle mass, lower and upper body power, Myf5 and Pax7 in the E+R was significantly greater than the R+E group. Myogenin (Myog) and Paired Box 3 (Pax3) significantly increased (P < 0.01) in both training groups compared to no changes in C.

CONCLUSION

An 8-week CT intervention improves SC related markers, body composition and enhances power and VO2max in older sarcopenic participants, regardless of the order of RT and ET. However, performing ET before RT may be more effective at enhancing skeletal muscle mass, Myf5 and Pax7, in addition to both lower and upper body power. While both CT programs produced notable physiological and performance benefits, performing ET before RT during CT may provide the greatest therapeutic benefits for aging individuals.

Overexploitation hazards and salinization risks in crucial declining aquifers, chemo-isotopic approaches

Bastam region is overusing its groundwater resources stocks. The groundwater levels, and hydrogeochemical data during a 14-year period (2002-2016) and isotopic composition (2016) of the 22 groundwater samples were investigated to determine the hydrogeological regime of Bastam Plain and identify the geochemical processes that control the groundwater quality. This plain is situated in a semi-arid region of northern Iran, mainly recharging from the carbonate Mountains in the north and southwest. In general, overexploitation of the groundwater due to low precipitation and changing precipitation regime has destructive effects on the hydrogeological setting and flow regime of Bastam crucial aquifer, including the decline of the groundwater level with rate of 0.9 m/year, water storage deficit of 17.32 Mm³/year and consequently, the intrusion of saline water towards the aquifer from the western and eastern salty plains. Based on the EC values, the groundwater samples divided into three groups of fresh waters with EC < 1000 μS/cm and Ca-Mg-HCO₃ water type which are located in the recharge zones, semi-saline waters (1000 < EC < 2500 μS/cm) with Na-Mg-Cl-SO₄ type at the center and saline waters with EC values more than 2500 μS/cm and Na-Cl type in the eastern and western parts of the plain. A few groundwater samples (group 2) fall on the mixing line between fresh and saline water in Piper diagram during the saline water intrusion, but most of the samples depart from this mixing line, indicating water-rock interactions in this area, resulting in deficit of Na⁺ and surplus of Ca²⁺ concentration. The fresh water samples cluster along the local meteoric water line in δ¹⁸O and δ²H relationships, suggesting an integrative and rapid recharge with meteoric water. Hydrochemical and isotopic characteristics indicate that invasion of the saline water resulted from halite dissolution with minor evaporation in the surrounding salty playas is the main origin for the increasing salinity in the Bastam aquifer. The salinization risks limit the groundwater withdrawals from Bastam aquifer in some areas, threatening the future sustainable development of the region.

Urokinase-plasminogen activator protects periodontal ligament fibroblast from oxidative induced-apoptosis and DNA damage

BACKGROUND AND OBJECTIVE

Urokinase-plasminogen activator (uPA) is a serine protease expressed at high basal level in normal gingival cervical fluid. Despite its known pathologic role in tissue proteolysis in periodontitis, little is known concerning uPA physiological function in oral tissue. Recent evidence in cancer cells has implicated the uPA system in DNA repair and anti-apoptotic pathways. This study is aimed to evaluate the protective function of urokinase against oxidative DNA damage in periodontal ligament (PDL) fibroblast, and to propose a new biological role for uPA in oral cavity.

MATERIAL AND METHODS

PDL cells were isolated from human wisdom teeth obtained from healthy donors. An oxidative stress model was created in which PDL cells were incubated with 20, 30, 40 and 60 μmol/L hydrogen peroxide. Twenty-four hours before and after peroxide treatment, cells were treated with uPA and amiloride. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5diphenyltetrazolium bromide assay, apoptosis by DAPI-staining and annexin V/propidium iodide assay, and DNA breaks by alkaline comet assay. For estimating DNA damage level, γ-H2AX expression was studied using flow cytometry and immunostaining.

RESULTS

The incubation of the peroxide-treated cells with uPA significantly increased cell viability and decreased apoptosis. A significant decrease in the number of γ-H2AX foci was seen at 30 μmol/L hydrogen peroxide in uPA-treated cells. uPA inhibition as a result of amiloride treatment, in turn, induced a reduction in cell viability. In addition, there was a significant decrease in the levels of DNA damage in uPA-treated groups as measured by the comet assay.

CONCLUSION

The present study brings support to the theory that uPA may have a protective role for periodontal tissue and could protect PDL fibroblasts from oxidative DNA damage and apoptosis.

Fracture Toughness of Nanohybrid and Hybrid Composites Stored Wet and Dry up to 60 Days

STATEMENT OF PROBLEM

Patients' demand for tooth-colored restoratives in the posterior region is increasing. Clinicians use universal nanohybrid resin composites for both anterior and posterior regions. There are few published reports comparing fracture toughness of nonohybrids and that of hybrid composite stored wet and dry.

OBJECTIVES

To investigate the fracture toughness of three nanohybrids compared to that of a hybrid resin composite stored dry or wet up to 60 days, using four-point bending test.

MATERIALS AND METHODS

Four resin composites were used: three nanohybrids; Filtek Supreme (3M), Ice (SDI), TPH3 (Dentsply) and one hybrid Filtek P60 (3M). For each material, 40 rectangular notched beam specimens were prepared with dimensions of 30 mm × 5mm × 2mm. The specimens were randomly divided into 4 groups (n = 10) and stored at 37ºC either in distilled water or dry for 1 and 60 days. The specimens were placed on the four-point test jig and subjected to force (N) using universal testing machine loaded at a crosshead speed of 0.5mm/min and maximum load at specimen failure was recorded and K_IC was calculated.

RESULTS

Three-way ANOVA showed a significant interaction between all the factors (all p < .0001). Except for TPH3, all tested materials showed significantly higher K_IC when stored dry than stored wet (p < 0.05). After 1 day of dry storage, Ice showed the highest K_IC (2.04± 0.32) followed by Filtek P60 and the lowest was for Filtek Supreme (1.39± 0.13) The effect of time on fracture toughness was material dependent.

CONCLUSIONS

Wet storage adversely affected the fracture toughness of almost all materials. Keeping the restoration dry in the mouth may increase their fracture toughness. Therefore, using a coating agent on the surface of restoration may protect them from early water uptake and increase their strength during a time period.

Central composite design optimization of pilot plant fluidized-bed heterogeneous Fenton process for degradation of an azo dye

Optimization of Acid Yellow 36 (AY36) degradation by heterogeneous Fenton process in a recirculated fluidized-bed reactor was studied using central composite design (CCD). Natural pyrite was applied as the catalyst characterized by X-ray diffraction and scanning electron microscopy. The CCD model was developed for the estimation of degradation efficiency as a function of independent operational parameters including hydrogen peroxide concentration (0.5-2.5 mmol/L), initial AY36 concentration (5-25 mg/L), pH (3-9) and catalyst dosage (0.4-1.2 mg/L). The obtained data from the model are in good agreement with the experimental data (R(2 )= 0.964). Moreover, this model is applicable not only to determine the optimized experimental conditions for maximum AY36 degradation, but also to find individual and interactive effects of the mentioned parameters. Finally, gas chromatography-mass spectroscopy (GC-MS) was utilized for the identification of some degradation intermediates and a plausible degradation pathway was proposed.

Effect of a self-adhesive coating on the load-bearing capacity of tooth-coloured restorative materials

BACKGROUND

The aim of this study was to compare the flexural strength and Vickers hardness of tooth-coloured restorative materials with and without applying a self-adhesive coating for up to 6 months.

METHODS

Specimens were prepared from three resin composites (RC), two resin-modified glass-ionomer cements (RM-GIC) and two conventional glass-ionomer cements (CGIC). All materials were tested both with and without applying G-Coat Plus (GCP). Specimens were conditioned in 37 °C distilled deionized water for 24 h, and 1, 3 and 6 months. The specimens were strength tested using a four-point bend test jig in a universal testing machine. The broken specimen's halves were used for Vickers hardness testing. Representative specimens were examined under an environmental scanning electron microscope.

RESULTS

Data analysis showed that regardless of time and materials, generally the surface coating was associated with a significant increase in the flexural strength of the materials. Applying the GCP decreased the hardness of almost all materials significantly (P < 0.05) and effect of time intervals on hardness was material dependent.

CONCLUSIONS

The load-bearing capacity of the restorative materials was affected by applying self-adhesive coating and ageing. The CGIC had significantly higher hardness but lower flexural strength than the RM-GIC and RC.

Oral health-related quality of life of removable partial denture wearers and related factors

This study aims to investigate the oral health-related quality of life (OHRQoL) in a group of removable partial denture (RPD) wearers in Shiraz (Iran), using the Persian version of the Oral Health Impact Profile (OHIP-14). Two hundred removable partial denture wearers had completed a questionnaire regarding patients' demographic characteristics and denture-related factors. In addition, the OHIP-14 questionnaire was filled out by interviewing the patients. Two measures of interpreting the OHIP-14 scales were utilised: OHIP-14 sum and OHIP-14 prevalence. The relationship of the patients' demographic characteristics and denture-related factors, with their OHRQoL was investigated. The mean OHIP-14 sum and OHIP-14 prevalence of RPD wearers were 13·80 (±10·08) and 44·5%, respectively. The most problematic aspects of OHIP-14 were physical disability and physical pain. Twenty-seven percentage and 24% of participants had reported meal interruption and eating discomfort, respectively. OHIP-14 prevalence and OHIP-14 sum were found to be significantly associated with factors representing RPD wearer's oral health such as self-reported oral health and frequency of denture cleaning. Furthermore, OHIP-14 prevalence and OHIP-14 sum were significantly associated with factors related to frequency of denture use such as hours of wearing the denture during the day and wearing the denture while eating and sleeping. Therefore, it can be concluded that the OHRQoL of the patients of the study was generally not optimal and found to be strongly associated with oral health.

Effect of a home bleaching agent on the fracture toughness of resin composites, using short rod design

STATEMENT OF PROBLEM

Resin composites are brittle materials and their major shortcomings are manifested in their sensitivity to flaws and defects. Although various mechanical properties of resin composites have been described, few studies are available on assessing the effect of bleaching agents on resin composites using the short rod design.

PURPOSE

To place various resin composites into distilled water at 37°C for 21 days and determine the effect of immersion time in distilled water, with and without exposure to 10% carbamide peroxide by employing short rod design fracture toughness test.

MATERIALS AND METHOD

Specimens were prepared from three resin composites; Rok (SDI), Esthet (Dentsply), and Estelite (Tokuyama). For each material, a total of 24 disc-shaped specimens were prepared using a custom-made mould. Specimens were randomly divided into 3 groups of 8 and conditioned in 37°C distilled water for either 24 hours, or 21 days. 21 day specimens were tested both with and without applying bleaching agent; Polanight (SDI). Study group specimens were bleached for 21 days, 2 hours a day. The specimens were loaded using a universal testing machine with a crosshead speed of 0.5 mm per minute. The maximum load at specimen failure was recorded and the KIc (MPa. M (0.5)) was calculated.

RESULTS

Statistical analysis using two-way ANOVA showed a significant relationship between material and time (p< 0.05).Tukey's test showed that after 24 h of immersion in distilled water, Rok revealed the highest KIc followed by Esthet and Estelite. The bleaching agent significantly improved the fracture toughness values of Esthet while it decreased that of Estelite.

CONCLUSION

The fracture toughness of the resin composites was affected by the bleaching agent and distilled water. In comparison with Rok and Estelite, fracture toughness of Esthet was increased due to aging and application of bleaching agent.

Effect of G-Coat Plus on the mechanical properties of glass-ionomer cements

BACKGROUND

Although various mechanical properties of tooth-coloured materials have been described, little data have been published on the effect of ageing and G-Coat Plus on the hardness and strength of the glass-ionomer cements (GICs).

METHODS

Specimens were prepared from one polyacid-modified resin composite (PAMRC; Freedom, SDI), one resin-modified glass-ionomer cement; (RM-GIC; Fuji II LC, GC), and one conventional glass-ionomer cement; (GIC; Fuji IX, GC). GIC and RM-GIC were tested both with and without applying G-Coat Plus (GC). Specimens were conditioned in 37 °C distilled water for either 24 hours, four and eight weeks. Half the specimens were subjected to a shear punch test using a universal testing machine; the remaining half was subjected to Vickers Hardness test.

RESULTS

Data analysis showed that the hardness and shear punch values were material dependent. The hardness and shear punch of the PAMRC was the highest and GIC the lowest. Applying the G-Coat Plus was associated with a significant decrease in the hardness of the materials but increase in the shear punch strength after four and eight weeks.

CONCLUSIONS

The mechanical properties of the restorative materials were affected by applying G-Coat Plus and distilled water immersion over time. The PAMRC was significantly stronger and harder than the RM-GIC or GIC.

Size tuning of Ag-decorated TiO₂ nanotube arrays for improved bactericidal capacity of orthopedic implants

Surface modification of orthopedic implants using titanium dioxide nanotubes and silver nanoparticles (SNs) is a promising approach to prevent bacteria adhesion, biofilm formation, and implant infection. Herein, we utilized a straightforward and all-solution process to prepare silver-decorated TiO2 nanotube arrays with surface density of 10(3) to 10(4) per µm(2). With controlling the synthesis conditions, hexagonal closed-packed nanotubes with opening diameter of 30-100 nm that are decorated with SNs with varying sizes (12-40 nm) were prepared. Various analytical techniques were utilized to characterize the size, morphology, distribution, valance state, surface roughness, and composition of the prepared antibacterial films. The bactericidal capacity of the films were studied on Escherichia coli (E. coli) by drop-test method and correlated with the size and percentage of Ag as well as the surface density of TiO2 nanotube arrays. Synergetic effect of TiO2 nanotubes and SNs on the antibacterial activity of the composite films is shown. The bactericidal capacity is found to depend on the size characteristics of the Ag-TiO2 coating. The highest antibacterial activity is obtained for TiO2 nanotubes with opening diameter of about 100 nm and SNs with an average size of 20 nm. MTT assay using osteoblast MG63 cells was performed to examine the cell viability. We suggest that release rate of the silver ions is an important factor controlling the antibacterial activity. Additionally, the size dependency of the bactericidal capacity implies that electrical coupling between silver and TiO2 nanotubes and improved hydrophobicity of the coating might influence the bacterial behavior of the hybrid nanostructures.

Application of artificial neural networks for optimization of preparation of insulin nanoparticles composed of quaternized aromatic derivatives of chitosan

The aim of this research was to develop an artificial neural network (ANN) in order to design a nanoparticulate oral drug delivery system for insulin. The pH of polymer solution (X1), concentration ratio of polymer/insulin (X2) and polymer type (X3) in 3 level including methylated N-(4-N,N- dimethyl aminobenzyl) chitosan, methylated N-(4-pyridinyl) chitosan, and methylated N-(benzyl) chitosan are considered as the input values and the particle size, zeta potential, PdI, and entrapment efficiency (EE %) as output data. ANNs are employed to generate the best model to determining the relationships between input and response values. In this research, a multi-layer percepteron with different topologies has been tested in order to define the one with the best accuracy and performance. The optimization was used by minimizing the error between the predicted and observed values. Three training algorithms (Levenberg-Marquardt (LM), Bayesian-Regularization (BR), and Gradient Descent (GD)) were employed to train ANNs with various numbers of nodes, hidden layers and transfer functions by random selection. The accuracy of prediction data were assayed by the mean squared error (MSE).The ability of all algorithms was in the order: BR>LM>GD. Thus, BR was selected as the best algorithm.

Molar-incisor hypomineralisation: a prevalence study amongst primary schoolchildren of Shiraz, Iran

AIM

To investigate the prevalence of molar-incisor hypomineralisation (MIH) amongst primary schoolchildren of Shiraz, Iran, taking into account the possible influence of biographic and socio-demographic parameters.

STUDY DESIGN AND METHODS

A randomised cluster sample of 9- to 11-year-old children (N = 810) had their first permanent molars and incisors (index teeth) evaluated using the European Academy of Paediatric Dentistry criteria for MIH. The examinations were conducted at schools by a calibrated examiner. Prevalence of MIH was assessed based on biographic and socio-demographic parameters including area of residency, school type, father's level of education, weight-for-age and height-for-age.

RESULTS AND STATISTICS

Of the children examined, 164/810 (20.2%) had MIH and 53.7% of them presented with MIH lesions in all first molars. Mild defects represented by demarcated yellow brown opacities comprised 35.5% of the total MIH lesions. The prevalence of MIH was significantly greater in girls, children with healthy body weight and height, those whose fathers did not have a tertiary education and from families of low socio-economic status. Regression analyses indicated that none of the biographic and socio-demographic variables represented a significant risk factor in the occurrence of MIH except for body weight. Obesity was negatively correlated to MIH (OR = 0.45; 95% CI 0.25-0.82).

CONCLUSIONS

The prevalence of MIH in a group of Iranian children was 20.2%. Biographic and socio-demographic parameters appeared to have no significant correlation with MIH except body weight, which warrants further research.

Film thickness and flow properties of resin-based cements at different temperatures

STATEMENT OF PROBLEM

For a luting agent to allow complete seating of prosthetic restorations, it must obtain an appropriate flow rate maintaining a minimum film thickness. The performance of recently introduced luting agents in this regard has not been evaluated.

PURPOSE

To measure and compare the film thickness and flow properties of seven resin-containing luting cements at different temperatures (37°C, 25°C and10°C).

MATERIAL AND METHODS

Specimens were prepared from five resin luting cements; seT (SDI), Panavia F (Kuraray), Varioloink II (Ivoclar), Maxcem (Kerr), Nexus2 (Kerr) and two resin-modified glass-ionomer luting cements (RM-GICs); GC Fuji Plus (GC Corporation), and RelyX Luting 2 (3 M/ESPE). The film thickness and flow rate of each cement (n=15) was determined using the test described in ISO at three different temperatures.

RESULTS

There was a linear correlation between film thickness and flow rate for most of the materials. Cooling increased fluidity of almost all materials while the effect of temperature on film thickness was material dependent. At 37°C, all products revealed a film thickness of less than 25µm except for GC Fuji Plus. At 25°C, all cements produced a film thickness of less than 27 µm except for seT. At 10°C, apart from seT and Rely X Luting 2, the remaining cements showed a film thickness smaller than 20 µm.

CONCLUSION

Cooling increased fluidity of almost all materials, however. the film thickness did not exceed 35 µm in either condition, in spite of the lowest film thickness being demonstrated at the lowest temperature.

Effect of storage media and time on the fracture toughness of resin-based luting cements

BACKGROUND

Resin-based cements are brittle materials and the major shortcomings of these materials are manifested in their sensitivity to flaws and defects. Although various mechanical properties of resin luting cements have been described, few fracture toughness test data for resin-based luting cements using the short rod design have been published.

METHODS

Specimens were prepared from five resin luting cements. For each material a total of 36 disc-shaped specimens were prepared using a custom-made mould. Specimens were randomly divided into six groups of six, immersed in two solutions: distilled water and 0.01 mol/L lactic acid at 37 °C for 24 hours, 1 month or 3 months. The specimens were loaded using a universal testing machine. The maximum load at specimen failure was recorded and the K(Ic) (MPa. M 0.5) was calculated.

RESULTS

There was a relationship between material, storage solution and time (p < 0.05). Nexus 3 showed the highest K(Ic) followed by Panavia F, Calibra, Smart Cem2 and seT.

CONCLUSIONS

The fracture toughness of the resin luting cements was affected by both time and storage solution. Comparable fracture toughness of conventional resin cement and self-adhesive resin cements was observed.

Essential oil compositions of Cymbopogon parkeri STAPF from Iran

Aerial parts of aromatic grass, Cymbopogon parkeri STAPF, were collected at flowering stage from Kerman province of Iran. The essential oil of air dried samples obtained by hydro-distillation method. The compositions of the essential oil were determined by the use of GC and GC-MS. Nineteen (98.7%) constituents were identified. The main constituents were piperitone (80.8%), germacrene-D (5.1%), santolinyl acetate (2.1%) and alpha-eudesmol (2.1%).

Grazing affects essential oil compositions of Artemisia sieberi Besser

This study was conducted in order to study the effect of grazing on quality and quantity of Artemisia sieberi essential oil in Kerman province of Iran. Vegetation sites of Artemisia sieberi under three grazing intensity (heavy, moderate and non-grazed) with the same ecological conditions were selected based on distance of water resource and nomad tent in Khabre National Park and near rangelands. Within each sits, two individual plants sampled at random in full flowering stage. The oils were obtained by hydrodistillation of air-dried samples and were analyzed by GC-MS. The main constituents of oils were as follows: non-grazed site; 1,8cineol (29.9%), myrcene (14.1%), moderate grazed site; myrcene (15.9%), 1,8cineol (15.1%), Eudesm-7(11)-en-4-ol (11.1%) and heavy grazed site; 4-tepinyl acetate (23.3%), davanone (21.9%), p-cymene (19%).