MUSTANSIRIA DENTAL JOURNAL

Aim of the study: Since the introduction of acrylic resin as a denture base material, it suffered from having unsatisfactory properties and processing method. So, the use of microwave cured technique for the acrylic as modified procedure to simplify the manipulation of laboratory procedure and reinforcing of polymer by materials such as fibers and nanoparticles can maintain good resin material and to overcome these limitations. This study was performed to evaluate the effect of adding polypropylene fibers with and without different concentration of ZrO2nanoparticles into resin on some properties such as surface hardness and roughness.

Aim of the study: The present study aimed to evaluate the effect of surface treatments of zirconia (sandblast with 50µm Al2O3, 0.01M NaOH) on the shear bond strength between zirconia substructure and veneering porcelain.
Materials and methods: Twenty-one (21) disk shape zirconia specimens were prepared with dimensions of (10mm) in diameter and (1mm) in height and sintered according to manufacturer instruction. Specimens were divided into three groups (n=7) according to surface treatment method; control group (C), sandblast with 50µm Al2O3 (SB), and sodium hydroxide (Na). Porcelain veneer (IPS-emax ceram, vita Germany) was applied on the zirconia specimens (5mm in diameter and 3mm in height) and fired according to manufacturer instruction. All specimens were then evaluated for shear - bond strength in a universal testing machine at 1mm/min cross head speed. The shear - bond strength value was then statistically analyzed with one-way ANOVA and LSD.
Results: The result of the present study showed that 0.01M NaOH has significantly effect on the shear bond strength between zirconia and porcelain than sandblast with 50µm Al2O3.
Conclusion: Sandblast with 50µm Al2O3 had no effect on the shear bond strength between zirconia substructure and veneering porcelain whereas 0.01M NaOH reduced the shear bond strength between them.

Aim of the study: The junction between metal alloy and acrylic resin is an area of clinical concern, failure of removable partial denture may relate to this interface. The purpose of this study was to evaluate the effect of different surface treatments (diazonium salt and aluminum oxide) on microleakage of heat cure acrylic resin at the Co/Cr and titanium alloys interface.
Materials and method: Sixty rectangular-shaped specimens divided into 2 main groups, 30 specimens for Co/Cr alloy and 30 specimens for titanium alloy, then subdivided into 3 groups each one consist of 10 specimens, according to the type of surface treatments. Aluminum oxide group abraded with (Al2O3) ll0 μm and diazonium salt group treated based on two steps, first step (primer) and second step (adhesive). Chemical composition of diazonium salt surface treatment was analyze with (FTIR). All specimens thermocycled in artificial saliva (3000 cycles) after clear heat cured acrylic resin application, then immersed in sodium fluorescein dye solution (0.1 g/1000mL) for 24 hours at room temperature. Microleakage was assessed by counting the grids that exhibited dye penetration under ultraviolet light. Data analyzed via One-way ANOVA and LSD test.
Results: Microleakage test showed a significant decrease in mean value between PMMA and treated Co/Cr or titanium with diazonium salt by 1.90 and 2.00 respectively (p<0.01). Aluminum oxide surface treatment revealed decrease in the microleakage test mean value between PMMA and treated Co/Cr or titanium by 3.55 and 3.70 respectively (p<0.01). The FTIR analyze showed functional groups of diazonium salt on surfaces for both Co/Cr and titanium.

Conclusion: Diazonium salt surface treatments for Co/Cr and titanium alloy showed a significant improvement in bonding strength in comparison to aluminum oxide surface treatment.

Aim of the study: The objective of this study was to evaluate the shear bond strength of acrylic denture teeth to different PMMA/MgO % (2%, 4%, and 6%) reinforcing nanofillers
Materials and method: 40 specimens of heat cure acrylic resin (PMMA) were prepared and divided into four groups 10 specimens for each group as follows; Control Group (Group1) without MgO nano filler particles; Group (2) with 2% by weight of MgO; Group (3) with 4% by weight of MgO and Group (4) with 6% by weight of MgO. Wax pattern sample which used for acrylic cylindrical shape fabrication were (25 mm in length and 5mm in diameter, the base of the cylinder which is 5mm in thickness and 8mm in length). Shear bond strength of all specimens was evaluated.
Results: Showed in the PMMA+MgO 4% showed the maximum mean value of upper bound of shear bond strength which was equaled to (14.859) while the control group PMMA recorded the minimum value of lower bound of shear bond strength (8.190).
Conclusion: There was no significant difference between control group PMMA and (PMMA+MgO 2%, PMMA+MgO 6%), but there was a significant difference between PMMA+Mgo4% compared with control group PMMA.

Background: Several new all-ceramic systems with superior aesthetic qualities such as translucency similar to natural tooth have been developed over the last two decades in response to the demand for metal-free and more natural-looking restorations. To achieve that, all-ceramic restorations, need characterization and glaze.
Objective: The objective of the present study was to evaluate the effect of glazing and polishing techniques on surface roughness (Ra) and Vickers hardness number (VHN) of feldspathic porcelain.
Materials and methods: Twenty-four layered zirconia discs (10 mm in diameter and 2 mm thickness) were designed by a special Sketchup 3d software program and saved as an (STL) file. All specimens were subjected to the polishing by using 600, 800, and 1200 grit of aluminum oxide paper in sequence. The specimens were divided into three groups each with eight samples (n=8) the first group was treated with glaze (G), the second group was polished with polishing kit (PK), and the third group was polished with polishing diamond paste (DPP). After the surface treatments were performed, the surface roughness was measured by using a profilometer and Vickers microhardness (VHN) was measured by using a digital microhardness tester. The surface characteristics changes were examined using a scanning electron microscope (SEM). Data were statistically tested with one-way ANOVA, Post-hoc Tukey’s test, and Least Significant Difference (LSD).


Results: Glazing and polishing techniques significantly affected the (Ra) and VHN of feldspathic ceramic. Group G showed significantly the lowest surface roughness (50±0.26) µm in comparison with groups PK (1.00±0.30) µm and DPP (70±0.42) µm. The largest VHN was obtained in a PK group (658.9±66) and the lowest VHN value was shown with the G group (538.4±36), while the VHN of DPP group was (652.8±66).
Conclusions: Glazed surface group had the lowest surface roughness and microhardness compared to the polishing kit and polishing paste groups. Therefore, glazing is recommended for finishing feldspathic porcelain, as it is more clinically acceptable, and it causes less wear to the antagonist's teeth.

Aim of the study: The purpose of the present investigation was to see how efficient silver diamine fluoride (SDF) solution treatment to prevent dental root caries.
Materials and method: This research was done at Iraq's geriatric facilities. Forty seniors with active caries lesions were fortuitously assigned into two groups: Group 1 (placebo control)—doubles Twice-Annual treatment with soda water; Group 2—Doubles Twice-Annual treatment with silver diamine fluoride solution.
Results: After 18 months, the arrest rates of root caries were 28 percent in group1 (control) and 88 percent group 2 silver diamine fluoride solutions (x2 test, p < 0.05). There was a considerable relation (dependent) between silver diamine fluoride and stopping root surface dental caries Chi=7.08, df=2, P<0.05, which means that silver diamine fluoride was efficient in stopping dental caries while there was no relation (independent) between placebo dye and arresting caries, Chi=1.33 df=2 P>0.05.
Conclusions: Silver diamine fluoride solution was helpful in avoiding root caries in elderly people who do not have access to fluoridated water.

Aim of study: The target of the present investigation was to compare the amount of apically extruded debris with three endodontic nickel -titanium instruments; ProTaper Gold, Reciproc Blue and Hyflex CM .
Materials and Methods: 30 mandibular premolars were separated into three groups according to the instrumentation methods (n=10) for every system, Protaper Gold, Reciproc Blue and Hyflex CM. After change of each file 5ml of 2.5% NaOCl was used as an irrigating solution with a 30G side vented irrigating needle, the apically extruded debris was collected in pre weighed glass vials, the samples were takeout and incubated at 68Co for 5 days to remove the liquid. The tubes were measured again, and the contrast between the first and last weight was calculated to determine the weight of the debris. The data were statistically analysed using One-way ANOVA analyses followed by Post hoc Tukey LSD test.
Result: Data obtained were statistically analyzed using One Way ANOVA and Post hoc Tukey LSD tests. All groups showed apical debris extrusion, The ProTaper Gold systems extruded more debris in comparison with other groups(0.0421)g, also the Protaper Gold group and Hyflex CM system showed statistically significant difference (p<0.05).
Conclusions: All experimental groups produced apically extruded debris .The Protaper Gold group associated with greater apically extruded debris than other groups. While the Hyflex CM group showed the least amount of apical extrusion

Aim of the study: The main goal of this study was to evaluate using of right-angle technique for detecting the impacted objects in maxilla and mandible arches in three dimensional radiographs.

Material and Methods: eighteen patients, seventeen were males, with one female age ranging from eighteen to twenty-four years (according to patients who attend to oral radiology dental clinic). The two radiographs are taken at the right angle to each other. This will indicate the tooth's position in the superior-inferior and anteroposterior relationships. Another radiograph was taken in true occlusal (cross-section) projection using an occlusal/periapical film will show the buccal (labial)- lingual and anteroposterior relationship.

Results: the contrast value for the radiographs, in this case, is the following number which is ≤ 0.5. It was significant it means acceptable from a statistics point of view, which the numbering is ≥ 0.5 it was non-significant which means most cases are highly significant from in statistic point of view.

Conclusion: according to values of outcomes and their significance can be used to the patient effectively detect this kind of impaction. Right angle technique is an effective to detect third dimension of impacted tooth (the depth) if it is buccally, lingually, mesially, distally or transverse. According to outcomes and its significance can be used to the patient effectively detect this kind of impaction.