فریبا بلوچ

The aim of this study was to investigate the shear bond strengthof composite to Emax porcelain using different methods of ceramic surface preparation (in vitro).

In this laboratory study, 36 porcelain disks were made and divided into four equal groups. The first group was prepared by sandblasting with 50 micron alumina particles, in the second group received porcelain level of 9.5% HF for 20 seconds. Group three was first sandblasted and then by HF 9.5% and the fourth group was first prepared by HF 9.5% and then by sandblasting and the same silane, bonding and composite were applied to 36 samples. Finally, their shear bond strength test was performed. The mean shear bond strength in MPa was analyzed by ANOVA (a = 0.05) and Tukey test. The fracture pattern of the samples was examined by stereomicroscope

The highest mean shear bond streght of the groups was related to sandblast +etching wigh HF(38.52±6.19 MPa), etching with HF+ sandblast (26.8±3.58 Mpa), etching with HF(23.28±4.03 Mpa), respectively and the least streght was reffered to sandblast (18.87±2.15 Mpa). The shear bond streght of composite to Emax porcelain in sandblast group was lower than sandblast and etching with HF group (p<0.001) and etching with HF and sandblast group (p=0.002). This value was significantly higher in sandblast with HF compare to etching with HF group (p<0.001). The Maximum Failure in all groups was cohesive type.

The highest mean shear bond strength of the groups was related to sandblast + etching with HF etching with HF + sandblasting, etching with HF and sandblasting. The most common type of failure in all groups was Cohesive.

Gag is a common complication during dental surgeries that can make the treatment problematic or even impossible. Previous studies have suggested various non-medicated interventions, such as distracting the patient, behavior therapy, hypnosis, acupuncture, and some  medications such as application of sedatives like Nitrox ide 30%, Midazolam, and oral Metobenzamid as well as herbal substances, such as date extract  and ginger. Using elaeagnus angustifolia extract for removing Gag reflex is another method which has received very little attention in literature. Thus, we made an attempt to examine the effect of elaeagnus angustifolia extract suck pills on gag reflex in the Dentistry Faculty in 2015.

A clinical trial was performed on 45 patients. Case group (Experimental 2) sucked the elaeagnus angustifolia extract tablet and control group received no intervention and placebo group (Experiment 1) was given a simulated non-extractable drink tablet similar in color and size to those of the original sample. The main condition for inclusion in the study was reflex of nausea and their consent to participate in the study. The tablet was manufactured ex vivo and then examined for nausea in random patients with mild stimulation of the palate with patients showing the appropriate level of feeling on a Glascow scale ruler. The patients with level 10 of nausea sucked the pill for 4 minutes and then we immediately stimulated them using abselang to measure the nausea on the patient's ruler.

The pre-intervention and mild subtype of nausea reflex were 10.6 in the control group, 10.8 in the placebo group, and 10.8 in the case group and 15.2, 14.8, and 15.4 in the mean group, respectively. Finally, in the severe subgroup, the values obtained were 17.6, 18, and 17.4, respectively, with insignificant differences (P <0.09).

It seems that elaeagnus angustifolia extract can reduce Gag reflex. However, we suggest that more extensive studies be carried out in this area.

Considering the prevalence of color changing of shade guides resulting from the use of disinfectants, the aim of the present study was to evaluate the effect of two disinfectants Desomed and Deconnex +53 on Vitapan shade guide.

Methods and materials:

The present experimental–in vitro study was conducted on a total of 30 A2 shade tabs. In the case group, 10 samples were merged in each of disinfectants and 10 sample were placed into distilled water as control group. Color selecting process was performed for 5 days, 3 times a day, by dentist. After 480 repeated cycles of this procedure, according to CIELab system, primary color of 10 samples were measured using Konica Minolta spectrophotometer as the control group. Also, color indices were measured making using of Vident spectrophotometer in the CIELAB system.  Statistical analyses were performed running Two-way ANOVA.

The rate of color change indices showed that the color changing (ΔE) indices for Deconex+53 and Desomed were 1.23∓0.55 and 3.69∓1.3, respectively. Thus, the ΔE of Desomed was twice more than that of Deconex +53. Our results revealed that the discoloration of Desomed was statically significant and higher than that of Deconex (p<0.001).

It can be concluded that Desomed has more color changes compared with Deconex in similar conditions.

 Given the dimensional changes in implant impressions and its complications, and the introduction of intraoral scanners that are likely to result in less dimensional changes, this study aimed to compare the dimensional changes of digital and conventional impression techniques in dental implants.

 The experimental study was conducted on 20 samples. First, a Ceramill laboratory scanner (Amann Girbach, Austria) was used to scan a stainless steel model. In the conventional impression group, an impression was taken with the open tray technique, and after pouring the cast, a digital model was prepared using a laboratory scanner. In the digital impression group, an intraoral scanner (Dentsplay Sirona, USA) was used to scan the stainless steel model 10 times. Each digital file obtained from groups 1 and 2 was superimposed on the Studio software environment (Geomagic® Studio 3D Systems, Rock Hill, SC, USA), and their dimensional changes were calculated. One-way ANOVA was used to evaluate dimensional changes of the two groups. Data were analyzed with SPSS 25.

 The results showed that the dimensional changes in conventional and digital impression groups were 0.178 ± 0.057 and 0.110 ± 0.43, respectively, with a significant difference.

 The impression accuracy for implant prostheses at different angles, using an intraoral scanner, was higher than the conventional impression technique using an impression material.

Nausea reflex during impression-taking is a concern that decreases the patient's ability to accept dental procedures. There are several methods for elimination of nausea reflex, Prescription of Metoclopramide is one of these pharmaceutical methods. The aim of this study is to evaluate effect of Metoclopramide on the elimination of nausea reflex during impression-taking in patients referring to Prosthodontics Department of the Faculty of Dentistry Tehran Medical Sciences, Islamic Azad University in 2018-19.

This research is a clinical trial study (before and after study) which was performed on patients referring to fix Prosthodontics department, faculty of Dentistry. Patients should have no medical problem, without any history of drug or any other type of allergy. Only patients with a nausea reflex VAS benchmark over 5, were included in this study. The patients were asked not to eat since 3 hours before impression-taking. Then the nausea reflex intensity before pharmaceutical treatment recorded. Afterwards, 1 ml (25 drops) of Metoclopramide hydrochloride along with 1 mg of sodium saccharin (as a sweetener) was prescribed. After half an hour, the intensity of the nausea reflex was measured again by the same VAS system, and the amount of change in the nausea reflex intensity was investigated by McNemar's statistical test in SPSS V25 software.

The study was performed on 28 eligible individuals, 46.4% male and 53.7% women, and 25-56 years old, all of whom had a nausea reflex VAS of more than 5, while after using Metoclopramide, all patients (100%) reported nausea reflex score of 5 or less (P <0.0001). The reflex intensity before and after pharmaceutical treatment was 9/7 ± 3/3 and 3.1± 1.4, respectively.

It seems that prescription of Metoclopramide can eliminate nausea reflex intensity during impression-taking in dental patients.

Alzheimer’s disease is a degenerative and progressive disorder resulting in cognitive impairment. Tooth loss is suggested as a significant risk factor for Alzheimer’s disease. In order to investigate the relationship of Eichner index and Alzheimer’s disease, this study is conducted at 2018 in the Neurology Department of Imam Hossein Hospital and Department of Prosthodontics, Dentistry faculty, Tehran medical sciences, Islamic Azad University. Eichner index was evaluated and registered by an examiner

This study was conducted as case-control design. Diagnosis of Alzheimer’s disease was made based on MMSE test by the neurologist as single blind design using biting wax. In order to quantification of Eichner index, numbers of 0 to 7 were assigned to sub-indexes of C to A1. The quantified Eichner index was statistically evaluated using Mann–U-Whitney test.

The study was performed on 140 samples (70 in study group and 70 in control group). The age for study group was 75.9±18.5 year and 76.5±14.3 year for the control group, which were not statistically different (p>0.05). Eichner index values was 1.16±1.63 for the study group and 2.3±2.07 for the control group. Statistical test showed that the difference between the two groups is significant (p=0.01).

Within the limitations of this article, it seems that there is a statistically significant relationship between Eichner Index and Alzheimer's disease and decreasing of posterior supporting dental occlusion was presented more in Alzheimer's disease patients vs. normal population.

The gradual color change of the tooth shade guide is due to the use of an autoclave is one of the clinical problems for correct color reproduction. The purpose of this research was study the effect of autoclave on dental shade guide. This experimental experiment was experimental and done on 20 dental paints guide (vitaA3). Subsequently, they were divided into 2 groups color guide by randomly. First, all specimens were washed Before placing in the autoclave Distilled for 3 minutes and they were dry with a tissue and they went on to the autoclave, of course The first group is at 121 °C for 40 minutes and the second group was kept at 134 °C for 10 minutes. These specimens were placed in an autoclave with 180 cycles and3 times a day, 5 days a week (equivalent to 3 months). At each stage set the Spectrophotometer color Indicators (abl) and Guide the color of the teeth. Statistical analysis was performed in SPSS software and in the way of Mann-Whitney. Mean in the group with a temperature of 121 degrees was 3.79 ± 0.63 and in the group with a temperature of 134 degrees, it was 3.55 ± 1.04 which are not significant. According to the statistical test, there is a difference (P <0.3). About b and c index, difference were minor and no significant difference was observed in the case of other measured indicators, L, a, H in the two groups.(P<0.2). The color change was more than 3.3 for both method and not acceptable related to clinical subjects. (3.55 and 3.79) In this study, it was observed that sterilization process by autoclave, can lead to change the color properties of the classic VITA color guide.

Posts are used as retention mechanism in repairing fractured or missing crowns of teeth. Nowadays composite fiber postes have eliminated most disadvantages of prefabricated metal and casting posts. the purpose of this study is to compare the amount of fracture resistance in three fiber posts (carbon fiber, quartzfiber, glass fiber) while shearing force (perpendicular to long axis) is applied. Materialsand This invitro, experimental study was performed on 30 maxillary lncisors with the same size without fracture, dentin caries or any root problems they were in three groups randomly. (Carbonfiber, quartzfiber, glassfiber) After root canal treatment and post space preparation with specified drill, samples were carried under universal test machine (prinston) to evaluate the amount of fracture resistance Data was analyzed with Kruskall،wallis Test under spss13. There was significant difference in fracture resistance in all three groups. (P=0. 001). Also, the carbon fiber posts had the maximum & the glass fiber posts had the minimum amount of fracture resistance. since the carbon fiber posts have the maximum fracture resistance in comparison with other groups, their application in anterior teeth is preferred.

The most important factor in the success of restoration is marginal fitness. If there is not an appropriate marginal fitness between tooth and restorations it may cause carries in the marginal area because of the food and debris in the marginal area cause gingivitis and margin discoloring and in sever cases it will have increase of pocket depth and loss of attached gingival from this problem caused this research. This is experimental research, the samples are 20 and there are chooses simple randomize. The mentioned marginal design were designed on a standard die by machines. Then impressions were provided from dies, and after making the restoration by electroforming method, the gap die and restoration measured by photo esterio microcope and T. Test. shoulder: 24.42 sloping shoulder: 13.92 P.value= 0.05 According to the P-value in comparing between of this two group of marginal design, there was significant difference. According to the significant difference, have the difference act about marginal fitness metoceramic restoration and sloping shoulder have better marginal fitness than shoulder in electroforming method.

Periodontal complication is one of the most important problems in patients after fixed prosthodontics placement, this means that, tissue affection in reaction to the placement of fixed crowns, can compromises gingival health. Because the metal ceramic crowns have both advantages of casting metal such as strength and sharpness and porcelain's beauty, they are more common than the other kinds of these restorations The aim of this study is to investigate of metal ceramic crowns effectiveness on abutments periodontal index, in the patients of fixed prosthodontics Department of Azad Tehran dentistry university in 1383-1384.Methods and Materials: In this quasi experimental, single blinde study 49 instances were studied by sequential sampling. Patients has no systemic or important physiologic problems and PI, GI and proximal contacts were normal(0). For improving periodontal health radiographic image performed for each specimen. All of the MC Crowns were made in fixed laboratory of dentistry university and alloy, porcelain materials, finish line were the same. After 3-6 months of crowns function, all of the indices evaluated and compared with base line data. Data analyzed by Mac Nemars, Q2 and ODD'S Ratio. Study showed that statistical differences were significant for gingival index(P<0.001)but no significant for plaque index and proximal contacts (P<0.5, P<0.9). After evaluation of Relation between periodontal index and Related factors(age, sex, usage of tooth brush and dental floss and abutment's location) showed that for gingival index, statistical differences were significant only in relation with "age" abutment's location" (P<0.06-P<0.005), With considering the results of this study, we can conclude MC Crowns, can increase the gingival index, after 3-6 months but have no significant effects on plaque index.