[Fracture resistance in two marginal designs of chamfer and shoulder in IPS emax restorations]

One of the problems of all ceramic restorations is their risk of fracture due to occlusal loads.The aim of the present study was to compare the effect of two marginal designs [shoulder and chamfer] on the fracture resistance of IPS-emax all ceramic restorations.One extracted maxillary first premolar received chamfer 50' marginal preparation [0.8 mm].Twenty impressions were made using poly vinyl siloxane. Then, chamfer was converted to shoulder 90'[1mm]. Afterimpression, epoxy resin dies were fabricated. Impressions of each epoxy resin die were made and poured with diestone. Twenty Press crowns and twenty ZirCAD crowns were made on stone dies and cemented on resin dies. Then,samples underwent a fracture test in a universal testing machine. Data were analyzed by one-way ANOVA.The mean fracture resistance was 1426N for the chamfer ZirCAD samples, 1361.3N for the shoulder ZirCADsamples, 1059.9N for the chamfer Press samples and 1295.8N for the shoulder Press samples. One-way ANOVA revealed no difference among groups. [p=0.095].After porcelain application, marginal design does not affect fracture resistance of single IPS-emaxposterior crowns. Fracture resistance was approximately the same in Press and ZirPress groups probably due to porcelain application, because in ZirCAD group fractures occurred in the porcelain prior to the core

[Stress distribution in three-implant-retained mandibular overdentures using finite element analysis]

Demand for implant supported overdentures has increased due to the problems of conventional dentures. Despite the high success rate of implants, implant failure remains a major challenge. Implant overload can cause cortical bone loss and implant failure. Using finite element analysis, this study aimed to find the best design and type of attachments causing minimum stress in the alveolar bone. The geometrical model of the mandible was produced using computed tomography [CT] data and three ITI implants were placed in the midline and the location of the first premolar teeth. All conditions were simulated using finite element software. Three bar-ball, bar and ball attachments were considered to support the overdenture. Maximum von Mises stress was calculated in the supporting bone in different overdenture designs. The results showed that the greatest amount of stress in bone was around the upper thread and the neck of the implant. The ball and the bar-ball attachments applied the most and the least amount of stress to the bone around the implant, respectively. Maximum stress was applied to the ball attachment in the bar-ball design. The maximum amount of movement was in bar-ball attachment. The bar-design decreased the stability of overdenture, as well as the stress in the peri-implant bone. Ball design increased concentration of stress in bone around the implant and increased the stability of overdenture

[Comparison of the effect of feldspathic porcelain and zirconia on natural tooth wear]

Enamel wear is among the main disadvantages of ceramic restorations. Recently, use of full zirconia crowns without dental porcelain has been suggested. The aim of this study was to compare the effect of feldspathic porcelain and zirconia on the wear of natural teeth. In this experimental study, 22 zirconia specimens were fabricated; out of which, 11 specimens were polished and chosen as zirconia specimens while the remaining 11 were used to fabricate porcelain specimens. A total of 22 natural human teeth were also obtained. The natural teeth were photographed by a stereomicroscope in a fixed position and the distance from the cusp tip to a reference point was measured. Next, 11 teeth opposed zirconia and the remaining 11 opposed porcelain specimens in a chewing simulator and subjected to 120,000 masticatory cycles. The teeth were photographed again and the greatest difference between the before and after values was recorded. The mean [ +/- standard deviation] wear rate was 153.8 +/- 95.68 and 306.3 +/- 127.74, in the zirconia and porcelain groups, respectively; and the two groups had a statistically significant difference in this respect [P=0.007]. The mean wear was significantly lower in teeth opposing zirconia than in those opposing feldspathic porcelain

Efficiency of the diamond versus carbide burs on the bond strength of composite to dentin in a self-etch bonding system

Nowadays, with regard to the quantitative and qualitative growth of dental-plastic services and qualitative advances made in tooth-colored restorations, there is a great rise of demands for use of composite resins. The aim of this study was to assess the efficacy of diamond burs in comparison with carbide burs on bond strength of self etch adhesives to dentin. In this in vitro experimental study, sixty sound extracted human third molars were selected and mounted in a self-cure acrylic resin. Then, teeth were randomly assigned to two groups, [n=30 each]: In group A the teeth were ground with high-speed medium grit diamond bur and in group B with high-speed carbide burs. A composite cylinder 3 mm in diameter was bonded to each specimen with a self-etch bonding system and the shear bond test with performed using a universal testing machine. The results were expressed in MPa and were subjected to and Tukey's test. The average shear bonding strength in diamond and carbide burs were 17.67 [SD= +/- 4.41] and 14.51 [SD +/- .18] MPa, respectively. There was a significant difference in dentin bond strength when comparing bonding strength between two groups [P< 0.05]. The use of different burs was considered influential on the shear bond strength of the self-etch adhesives 'to dentin. This adhesive significantly outperformed when a diamond bur was used to prepare dentin surface

comparison between shear bond strength of VMK master porcelain with three base-metal alloys [ni-cr-t3, verabond, super cast] and one noble alloy [x-33] in metal-ceramic restorations

Statement of Problem: The increase in the use of metal-ceramic restorations and a high prevalence of porcelain chipping entails introducing an alloy which is more compatible with porcelain and causes a stronger bond between the two. This study is to compare shear bond strength of three base-metal alloys and one noble alloy with the commonly used VMK Master Porcelain

Materials and Method: Three different groups of base-metal alloys [Ni-cr-T3, Super Cast, and VeraBond] and one group of noble alloy [X-33] were selected. Each group consisted of 15 alloy samples. All groups went through the casting process and change from wax pattern into metal disks. The VMK Master Porcelain was then fired on each group. All the specimens were put in the UTM; a shear force was loaded until a fracture occurred and the fracture force was consequently recorded. The data were analyzed by SPSS Version 16 and One-Way ANOVA was run to compare the shear strength between the groups. Furthermore, the groups were compared two-bytwo by adopting Tukey test

Results: The findings of this study revealed shear bond strength of Ni-Cr-T3 alloy was higher than the three other alloys [94 MPa or 330 N]. Super Cast alloy had the second greatest shear bond strength [80. 87Mpa or 283.87 N]. Both VeraBond [69.66 MPa or 245 N] and x-33 alloys [66.53 MPa or 234 N] took the third place

Conclusion: Ni-Cr-T3 with VMK Master Porcelain has the greatest shear bond strength. Therefore, employment of this low-cost alloy is recommended in metalceramic restorations

Comparison of retentive force in four attachment systems in implant-supported overdenture of the lower arch

Statement of Problem: Along with the rapid population growth in recent decades, there has been an increase in the number of edentulous patients who have complications with conventional denture. This entails the use of dentures, such as implant overdenture, which are more efficacious

Purpose: The purpose of this study is to compare four types of different attachment systems; two prefabricated and two castable attachments

Materials and Method: A model of lower edentulous arch was constructed out of dental stone. Two parallel implants were placed in the canine region. A single cast metal chrome cobalt framework was fabricated to provide reinforcement for experimental overdentures and it splinted the two attachments on the cast. To conduct this study, four groups with six numbers of attachments in each group [superflex ball, locator, castable ball on bar, castable bar] were selected. All the samples were put in a Universal Testing Machine and a tension force with the speed of 50 mm/ min was exerted to separate the framework from the cast. The tension force was recorded and the first two prefabricated attachments [superflex ball and locator] were compared with the second two castable attachments [ball on bar, castable bar]

Results: The findings of this study revealed that retention force of castable ball on bar was greater than the other three attachments [35.31 +/- 3.14N]. With regard to the strength of retentive force, superflex ball took the second place [33.33 +/- 3.11 N] and locator [20.90 +/- 3.74N] and castable bar [14.74 +/- 1.15N] took the third and the forth places, respectively [ p <0.001]

Conclusion: The retentive force of castable ball on bar was similar to that of superflex ball. Therefore, the use of this cheap attachment; castable ball on bar, is preferred to its prefabricated counterparts. The retentive force of this kind of attachment is greater than expensive locators. The retentive force of castable bar was similar to that of locator, although the former was a bit weaker than the latter. Therefore, when less retention is needed, castable bar can be a suitable choice, and when more retention is needed, castable ball on bar is preferable

[Effect of Papaverine on human serum albumin glycation]

Glycation is a non enzymatic reaction initiated by the primary addition of sugar to the amino groups of proteins. In the early stage of glycation, the synthesis of intermediates leading to formation of Amadori compounds occurs. In the late stage, advanced glycation end product [AGE] are irrevesibly formed after a Complex cascade of reaction. Survey effect of Papaverine on Human Serum Albumin Glycation. In this study HSA incubate with Glucose and different papaverine concentration for 42 days at 37degreeC. also HSA incubate alone [control sample], with Glucose[glycated sample] and with different papaverine concentration [without Glucose] respectively under the same conditions. Then samples survey with circular dichroism, fluorescence and UV spectroscopy. HSA glycation increase in proportion to papaverine concentration. samples contain Glucose and papaverine show more change in secondary structure, free amino groups and AGE fluorescence in relation to glycated and control samples. In glycated alpha helix and beta sheet show 5.7% decrease and 3.1% increase in comparison to control respectively. glycated show 14.2% fluorescence more than control. Free lys number in glycated show 8% less than control sample. All this cases show more change in samples which contain papaverine and Glucose. seem papaverine change HSA and cause more lys contact with sugar thus papaverine increase glycation

Study on epidemiological, clinical and laboratory characteristics of children with Henoch-Schoenlein Purpura

Henoch-Schoenlein Purpura [HSP] is the most common vasculitiis in children. It is characterized by non-thrombocytopenic purpura, arthritis and arthralgia, abdominal pain, gastrointestinal hemorrhage and glomerulonephritis. This study was conducted to determined epidemiological and clinical manifestations and laboratory findings of children who admitted with HSP at university hospitals of Ahvaz. Information about the epidemiological, clinical and paraclinical characteristics of patients were selected from hospital records of all 63 children with final diagnosis of HSP who were admitted in pediatric wards in university hospitals of Ahvaz during February 2001 to February 2008. Data analyzed by SPSS software. There were 63 children, 41[65%] males and 22 [35%] females [M/F ratio: 1.86/1]. The mean age of the patients was 6.4 [ +/- 3.15] years. Previous history of upper respiratory tract infections was found in 42.9% of the patients. In the review of clinical features, skin manifestations, gastrointestinal symptoms, arthritis/arthralgia and evidences of renal involvement were found in 100, 76, 66.7 and 39.6% of cases, respectively. The neurological signs were not found. Anemia, gastrointestinal bleeding, nephrotic syndrome and intussusception were found in 47.6, 19, 6.3 and 3.2% of cases, respectively. We found that relative to other studies, gastrointestinal manifestations in our patients were more common and more severe than arthicular manifestations. But, the final prognosis was good with no mortality

[Clinical and laboratory evaluation of cystinotic patients admitted at mofid and labafinejad hospitals [in Tehran] and Abuzar children's hospital in Ahvaz]

Cystinosis is a rare autosomal recessive disorder caused by accumulation of cystine in different organs. Infantile cystinosis characterized by Fanconi syndrome and growth retardation leading to renal failure. The aim of the study was to evaluate the clinical and laboratory findings of cystinotic patients attending at Mofid, Labafinejad hospitals [in Tehran] and Abuzar children's hospital [in Ahvaz], Iran. During 1995-2010, all children with cystinosis hospitalized at the above three centers were enrolled. Patients with the following criteria were considered as cases of cystinosis: i] signs and symptoms of Fanconi syndrome ii] Presence of cystine crystals in cornea using slit lamp. Of all the subjeces, 44 children fulfilled the criteria of nephropathic cystinosis. There were 24 [54.05%] females and 20 [45.5%] males. Among them, 21 [47.7%] cases were Arabs. The mean age of onset of symptoms was 8 [range 3-18] months. The mean age at the initial presentation of chronic renal failure was 3 years. The most common clinical features in the patients were growth retardation [100%], presence of cystine crystal in cornea[100%], rickets[86%] and polyuria-polydipsia [83%]. The commonest laboratory data were glucosuria [100%], renal tubular acidosis [97%], proteinuria [88.5%] and hyposthenuria [82%]. Sixteen [36.3%] of the 44 patients received kidney transplant, of which 7 [43.7%] patients rejected their grafts. Finally, 13 [29.5%] of them were relatively good on medical treatment, 8 [18.1%] died, 2 [4.5%] on waiting list of kidney transplant and 21 [47.7%] missed follow up. Although cystinosis is a rare disease in the world, it seems to be a relatively common hereditary disease with unfavorable prognosis in Iranian Arabs

[Ali ibn Abbas al-Majusi Ahvazi Arjani]

Ali ibn Abbas al-Majusi Ahvazi Arjani, known in Europe by his latinized name, Haly Abbas or Ali Abas, was born in Ahvaz or Arjan [Behbahan], located in the Southwestern Iran, in 930 AD. Al-Majusi is best known for his Kitab Kamil as-Sina'a at-Tibbiyya ["Complete Book of the Medical Art", in Latin "Liber Regius"]. The book was not only entirely based on the work of others, but also al-Majusi included his own observations. He dedicated this book to King Adhud al-Dawlah Dilami [died in 983 AD]. Al-Majusi served as court physician and worked in the Adhudi hospital in Baghdad. The Maliki is divided into 20 discourses, of which the first ten deal with theory and the second ten with the practice of medicine, such as surgery. It also contains many ethical parameters. Accordingly, it was the textbook on medicine for several centuries after the book was translated into Latin, and it was widely used not only in Persia and Arabic countries, but also in many parts of Europe. He died in Baghadad or Shiraz in 994 AD

[Fabrication of a sectional impression tray and a collapsible removable complete denture in a microstomia patient: a clinical report]

An abnormally small oral orifice is defined as microstomia which is caused by various factors like burning, scleroderma, etc. This disorder is difficult to treat due to the reduced oral opening. In particular, fabrication of removable prostheses is further complicated by tongue rigidity and the constant adjustment required to accommodate the changing periphery; however, successful treatment is possible through specific measures

In this article, a 41-year-old woman living in Baghmalek, Khoozestan was referred to the Prosthodontic department of Jondishapoor University in Ahvaz, southern Iran. She was suffering from microstomia and poor manual ability caused by scleroderma. Initial impression was prepared for her, using Silicon impression material by applying fingers pressure. The final impression was prepared using a two section tray so that the larger part covered one third of the smaller one and both could be attached by compressable button. Then the occlusal relation was established using occlusal rims connected to the two section parcels. Two part parcel prostheses connected with attachments were made for the lower and upper jaws, respectively. The patient was followed up for six months

Conclusion: In order to overcome the above-mentioned problems, the new method of removable prosthesis enjoys the advantage of sufficient precision as well as ease of use by the patient. For further evaluation, diagnosis and proper treatment plan are reported

[Study of bone turnover markers and inflammatory disease activity in rheumatoid arthritis patients visiting rheumatology clinic of Loghman hospital during 2008-09]

Rheumatoid arthritis [RA] is the most common inflammatory arthritis affecting 0.5 to 1% of the general population worldwide. The cause of RA remains unknown. In active RA, bone turnover markers change in serum and urine before the appearance of erosions in radiography. In this study, we compared RA activity index with bone turnover marker levels in serum of RA patients. In this cross-sectional study, RA patients referring to the Rheumatology Clinic of Loghman Hospital were studied. One hundred fourteen established RA patients were included. Bone turnover markers were measured in 75 patients. DAS28 and cumulative dose of steroid were calculated in all patients. RF, Anti-CCP, ESR, CRP, bone turnover markers consisting of osteocalcin, P1NP, betaCTX and ALP were measured for all the patients. Cases were divided based on whether steroid and DMARD were used or not. Comparison of DAS28 and bone turnover markers was done with Chi square Pearson test. Also, the relation between bone turnover markers and consumption of DMARDs, steroid and bisphosphonate was evaluated. SPSS V. 16 was also used for data analysis. There was significant correlation between DAS28 and serum osteocalcin [p<0.05], but no correlation was found with other markers. There was significant correlation between bisphosphonate consumption and decreased serum osteocalcin [p=0.05] and borderline correlation with decreased P1NP [p=0.06]. Significant correlations was found between "erosion and decreased level of osteocalcin" and "erosion and DAS28".In active RA patients, decreased bone formation markers especially osteocalcin are suggestive of severe and erosive disease for which early aggressive treatment is recommended. These markers can be applied for differentiating osteoporosis from RA in these patients. Thus increased level of bone formation markers is seen in idiopathic osteoporosis and decreased level in active RA

[Underlying causes of acute renal failure in children admitted to Abuzar children's hospital in Ahvaz]

Acute renal failure [ARF] can be pre-renal, intrinsic renal or post-renal in etiology. The aim of the study was to assess the causes of ARF in patients admitted to Abuzar Children's Hospital in Ahvaz, a referral center in the South Western of Iran. The records of patients managed as ARF were reviewed in our center from 2003 to 2006. ARF was defined as doubling of baseline serum creatinine associated with oliguria. A patient with evidences of chronic kidney disease was excluded. Based on the data, these causes were categorized in 3 groups as: pre-renal, intrinsic renal and post-renal. Totally 113 admitted patients had the criteria for ARF. There were 77 [68%] males and 36 [32%] females [M/F: 2.2]. The mean age was 6.8 years [ranging from 10 days to 15 years], but most of the patients [34.5%] were 5-10 years old. The underlying causes of ARF were 74.4% intrinsic, renal 18.6% pre-renal and 7% post- renal. Among 84 patients with intrinsic renal failure, 63 [55.7%] had acute glomerulonephritis [AGN]. The underlying causes of ARF in our region were different from other parts of the world. The most common causes of ARF were AGN and ATN due to scorpion sting and severe dehydration secondary to acute gastroenteritis. Therefore, most of these cases can be preventable by improving primary health care and by early and prompt treatment of infection and dehydration

[Study on the efficacy of oral prednisolone therapy among hospitalized women with hyperemesis gravidarum in Ahvaz Jundishapur university's hospitals]

Hyperemesis gravidarum [HEG] is a debilitating illness affecting 0.3- 2% of pregnant women. It is characterized by continuous vomiting, dehydration, ketosis and muscle weakness. Conservative measures are not effective in severe cases. In these conditions, prednisolone therapy has been used, but yet there is no consensus on the therapy. The aim of this study was to assess the effect of prednisolone therapy in control of symptoms in women with HEG. A randomized, placebo-controlled trial was conducted on women with HEG who were admitted at Ahvaz University's hospitals from April 2006 to March 2008. Initially, they were divided in two [Prednisolone and placebo] groups. The prednisolone group was administered oral daily prednisolone [20 mg bid] until improved, and then tapered off over a few weeks, while the control group was given a placebo [multivitamin] with the same manner. All women also received promethazine, metoclopramide, intravenous fluids with electrolytes and vitamin supplements [B1, B6]. Finally, 54 women in two groups [steroid: 28, placebo: 26] were analyzed. The mean age in both groups at admission was about 22 years. The mean gestational age at randomization was 10.7 [ +/- 2.3] weeks in the prednisolone group and 8.4 [ +/- 1.7] weeks in the placebo group. Among prednisolone group only 10 [35.71%] women versus 15 [57.68%] women in the placebo group needed hospital cares for women more than one week [P= 0.18]. Severe vomiting was seen only in 4 [14%] patients in the prednisolone group compared with 12 [46%] in the placebo group [P=0.01]. Nineteen women [73%] in the placebo, compared with 12[50%] in the prednisolone group, were readmitted for hyperemesis [P=0.03]. After one week, ptyalism was seen in 6 [6/12] in the prednisolone group versus in one [1/4] in placebo group [P=0.59]. Prednisolone therapy is useful in resolution of symptoms in women with hyperemesis gravidarum. Further study with a larger size is recommended