comparison of the reproduction of surface detail of three tissues conditioning materials over time

Statement of Problem: Although the basic use of tissue conditioners is to treat inflamed mucosa, they are also employed as functional impression materials. No information was obtained on the reproduction of surface detail of these materials over time

Purpose: The purpose of this study was to evaluate changes in the surface quality of three tissue conditioners after being immersed in water for a period of time

Materials and Method: Detail reproduction was determined by using from a ruled test block the same it was specified in ISO Specification 4823. Three tissue conditioners [GC, Acrosoft, and Visco-gel] were evaluated. Samples were made by pouring freshly mixed materials into a ruled test block. The samples were then stored in distilled water for either of the followings periods of time: 0 hour, 24 hours, 3 days, 7 days, 14 days. Subsequently, the dental stone was mixed with distilled water and poured on each sample and allowed to remain for 60 minutes. Then, 25 specimens were prepared. The detail reproduction was determined based on what is specified in ISO Specification 4823. The samples were examined under a stereo-microscope with low-angle illumination. The data was analyzed through running Kruskal-Wallis Test and Mann-Whitney Test

Results: The three materials had minimum standard of detail reproduction. The detail reproduction were more significantly influenced by the time period of immersion in water [p <0.0005] than the type of the material. The best detail reproduction was pertained to Visco-gel not immersed in water. Acrosoft was less influenced by the time period of immersion in water than the two other types

Conclusion: The detail reproduction may be attributed to chemical composition. The type of material and immersion time had a significant effect, while the effect of the type was less significant. The best time for making functional impressions was ranges from 0 to 24 hours

Radioresponse of human lymphocytes pretreated with boron and gadolinium as assessed by the comet assay

Boron and gadolinium are among the nuclides that hold a unique property of being a neutron capture therapy agent. Neutron beams have often a considerable portion of gamma rays with fast neutrons. Gamma rays, as beam contaminants, can cause considerable damage to normal tissues even if such tissues do contain high boron concentrations. The modification of radioresponse in human lymphocytes pretreated with boron or gadolinium compound was studied by assessing the DNA damage using single cell gel electrophoresis [SCGE], the comet assay. The lymphocytes from the human peripheral blood were irradiated with 0, 1, 2 and 4 Gy of gamma rays from a 60Co isotopic source with or without pretreatment of boron or gadolinium compound for 10 minutes at 4°C. Post-irradiation procedures included slide preparation, cell-lysing, unwinding and electrophoresis, neutralization, staining, and analytic steps, gel electrophoresis. The results indicate that pretreatment with boron compound [50 nM or 250 nM of 10B] is effective in reducing the radiosensitivity of the lymphocyte DNA. Conversely, pretreatment with gadolinium compound [50 nM] led to a dose-dependent increase in the radiosensitivity, most prominently with a dose of 4 Gy [P<0.001]. Furthermore, when the lymphocytes were pretreated with a combined mixture [1:1] of boron [250 nM] and gadolinium [50 nM] compounds, the reduced radiosensitivity was also observed

[Local anesthesia in vitreoretinal surgery]

To compare general anesthesia [GA] with local anesthesia [LA] in terms of safety and patient satisfaction. In this interventional case series, 928 consecutive patients who underwent vitreoretinal surgery were included. Data for analysis were type of anesthesia and operation, patient compliance, operating conditions and pain scores. General anesthesia was provided with a standard method and local anesthesia was performed through peribulbar or retrobulbar routes. Selection of the type of anesthesia was determined by patient age and co-morbidities based on the surgeon's opinion. Patients were operated under local anesthesia in 343 [36.9%] and general anesthesia in 585 [63.1%] cases. Mean age was 68.8 +/- 7.3 [range 51-78] years in the LA group and 55.9 +/- 6.5 [range 43-70] years in the GA group [P= 0.041]. ASA [American Society of Anesthetics] physical status score in the LA group was higher than GA group. Patients were in appropriate condition in 96.4% and operating conditions were good or excellent in 98.8%. The majority of patients [97%] said they would choose local anesthesia for their next vitreoretinal procedures. Local anesthesia is a useful and flexible method of anesthesia for vitreoretinal surgery, with excellent patient tolerance, especially in old patients and those who suffer from concurrent diseases

[Nd:YAG membranotomy in diabetic premacular hemorrhage]

To evaluate the success rate of Nd:YAG laser membranotomy in patients with diabetic premacular hemorrhage. This interventional case series included 24 eyes of 22 patients referred to retina clinic of Farabi Eye Hospital, Tehran, Iran during 2000-2007 with chief complaint of sudden loss of vision and clinical diagnosis of premacular hemorrhage due to proliferative diabetic retinopathy. All patients underwent complete ocular examination and color fundus photography. Nd:YAG laser membranotomy was performed in patients with >3 DD hemorrhage. Main outcome measures were success rate of membranotomy, improvement of visual acuity and the complications. Twenty-four eyes of 22 patients [68.2% female and 31.8% male] with diabetic premacular hemorrhage were enrolled. Mean age of patients was 56 +/- 6.5 years. Nd:YAG laser membranotomy was successful in 71% of patients resulting in release of trapped blood into the vitreous cavity which absorbed during 14.3 +/- 5.03 [range 8 to 27] days. Range of preoperative visual acuity was from hand motion to count finger at 4 m which improved to a range of 20/100 to 20/25 postoperatively. Patients complained of some visual disorders such as blurred vision and floater over 23-86 days [mean 43 days], postoperatively. Macular photocoagulation was performed in 11 eyes with macular edema before panretinal photocoagulation. Mean follow-up period was 34.7 +/- 18.3 [range 10-71] months. Nd:YAG laser membranotomy in diabetic premacular hemorrhage is a simple and inexpensive outpatient procedure which results in rapid visual recovery and is relatively safe. Further controlled clinical trials are recommended

[Incidence, severity and risk factors for retinopathy of prematurity in premature infants with late retinal examination]

To determine the incidence, severity and risk factors for retinopathy of prematurity [ROP] in premature infants with late retinal examination at Farabi Hospital from 2001 to 2006. In a cross-sectional study, hospital records of premature infants who were examined later than 9 weeks after birth were reviewed for possible risk factors of ROP including gender, singleton or multiple gestations, gestational age [GA], birth weight [BW], oxygen therapy, blood transfusion, phototherapy, and respiratory distress syndrome [RDS], as well as the age at initial examination. From 693 infants referred for ROP screening, 191 [27.6%] had late retinal examination at mean age of 144.8 +/- 158.4 [range 64-1460] days. Of these 191 infants, 75 [39.3%] had different stages of ROP, 58 [30.4%] had stage 4 or 5 disease and 27 [14.1%] had stage 5 ROP in both eyes which were untreatable. GA and BW were associated with development of ROP [P<0.001]. The high prevalence of premature infants with late retinal examination and high incidence of severe ROP necessitates prompt intervention to optimize referral and early screening of premature infants

[Effect of second wash in one and two step impression techniques on dimensional accuracy of stone models]

Statement of Problem: The most common impression techniques used in fixed prosthodontics are one and two step with spacer. Sometimes impression details are not registered and as a result, use of second wash would be necessary

Purpose: The aim of this study was to evaluate the effect of second wash of speedex impression material on dimensional accuracy of stone model in one and two stage impression techniques

Materials and Method: In this experimental study, two metallic dies [with and without undercut] were used. Impressions were made using four techniques [one step, one step with second wash, two steps, and two steps with second wash]. For each technique the impression taking was repeated 15 times and totally 60 impressions were provided. Impressions were poured with Vel-mix stone. Height and diameter for each die as well as distances between the dies were measured by sterio microscope and data were analyzed using ANOVA and T-tests

Results: This study showed that in all four techniques height of dies with undercut was increased, but in the two step technique, the difference was not statistically significant [p= 0.282]. In one step and two step with second wash technique, heights of dies without undercut were increased, while in the other two techniques they were decreased. In two step technique, diameters of the two dies were increased, while in other techniques they were decreased. In the two step technique, the distance between the dies was decreased, mean while other techniques did not show any increase and the differences were not statistically significant [p<0.05]

Conclusion: The two step technique was more accurate than the other techniques. The one step with second wash technique was more accurate than one step technique. The use of two step with second wash technique is not recommended in fixed partial dentures, but in single crowns it can be used only with special considerations

[Setting time and consistency of three kinds of irreversible hydrocolloid impression materials]

Taking impression plays an important role in prosthodontic treatments. Alginate impression materials are very common in this regard. With due attention to the importance of setting time and consistency of impression materials, researches for comparison the properties of different impression materials are necessary. This study was conducted to investigate the setting time and consistency of two Iranian alginates [Regular Iralgin and Super Iralgin] in comparison with one imported brand, Bayer alginate using ADA [No.18] and ISO [1563] specification. In this in vitro study, 51 samples [17 samples of each alginate, Bayer, Regular Iralgin and Super Iralgin] were prepared. Setting time and consistency of these materials were compared according to Iranian standard Institute, specification 1563. To analysis the data, t-test and ANOVA were used. Mean of consistency and seting time from maximum to minimum was including Bayer, Regular Iralgin and Super Iralgin. According to the result of this experiment, the three materials showed acceptable setting time and consistency according to Iranian Standard Specifications. ANOVA analysis showed no significant differences in consistency among these materials [p>0.05] whereas there were significant differences in setting time between Bayer alginate and Iranian brands [p<0.05]. The three impression materials used in this study showed acceptable setting time and consistency. There was significant difference in setting time among them, which could be related to the composition of these materials. More studies are needed to be conducted on other properties of these materials

Therapeutic effect of macular grid photocoagulation in treatment of nonexudative age-related macular degeneration

To investigate the effect of prophylactic subthreshold laser macular grid photocoagulation on drusen area and to evaluate the visual outcome and incidence of choroidal neovascularization in patients with soft drusen maculopathy. In a nonrandomized nonmasked clinical trial, 18 patients [36eyes] with bilateral soft drusen maculopathy were studied. For each patient, one eye was treated with 48 subthreshold [invisible end-point] applications of 532-nm KTP-laser in a macular grid pattern and the fellow eye was observed. Soft drusen areas were calculated and compared between the two groups at baseline and follow-up visits at 3, 6, 12, and 30 months of therapy. Best corrected visual acuity was also compared in observed and laser-treated eyes. Reduction of drusen area, change in visual acuity, and rate of CNV were assessed in both groups. At baseline, there was no significant difference in the mean drusen surface area between the two groups [P=0.90]. The mean surface area of soft drusen in treated eyes was6.51 mm[2] after 30 months and 7.58 mm[2] [P=0.50] in the control eyes. There was a trend towards reduction in the mean soft drusen area after 30 months from baseline in laser-treated eyes [6.51 vs6.97 mm[2]]. In treated eyes, there was no statistically significant difference between the mean best corrected visual acuity at the baseline [0.28 logMAR] and after 30 months [0.32 logMAR] [P=0.40]. Subthreshold macular grid photocoagulation with 532-nm KTP-laser did not seem to reduce drusen surface area significantly and did not improve best corrected visual acuity after 30 months. No exudative lesion developed in laser-treated eyes

[Intravitreal triamcinolone for treatment of refractory diabetic macular edema]

To determine if intravitreal injection of triamcinolone acetonide is safe and effective in the treatment of diabetic macular edema unresponsive to prior laser photocoagulation. Fifty-four eyes of 38 patients with clinically significant macular edema which had received at least two sessions of laser photocoagulation according to Early Treatment Diabetic Retinopathy Study guidelines were enrolled in this study. At least four months after laser therapy; eyes with residual central macular thickness [CMT] greater than 250 microm on optical coherence tomography [OCT] and visual loss from baseline were offered intravitreal injection of 4 mg triamcinolone acetonide. Visual and anatomic responses as well as complications related to the injection procedure and corticosteroid medication were observed. Mean baseline best corrected visual acuity [BCVA] and CMT were 0.77 +/- 0.5 LogMAR and 443 +/- 138 microm, respectively. All patients completed one month of follow up and 39 of 54 eyes [72.2%] completed 6 months of follow up. Mean BCVA was 0.64 +/- 0.45, 0.56 +/- 0.48, and 0.79 +/- 0.55 LogMAR at months 1, 3, and 6, respectively. Central macular thickness measured by OCT decreased by 39% and 23.5%, at the third and sixth month visits, respectively. Intraocular pressure exceeded 21 mmHg in 36.3% of the eyes. Cataract progression was noted in 12.8% of phakic eyes. Intravitreal triamcinolone seems a promising therapeutic method for diabetic macular edema refractory to conventional laser photocoagulation without any significant complication, however the effect seems to be temporary. Further studies are warranted to assess the long-term efficacy and safety and also the need for retreatment

[Intravitreal triamcinolone acetonide in chronic refractory uveitis]

To evaluate the effect of intravitreal triamcinolone acetonide injection for management of chronic refractory uveitis in terms of inflammation, visual acuity and macular thickness. This interventional case series was conducted on uveitic eyes with no remission despite proper administration of periocular and/or systemic steroids. After systemic and rheumatologic evaluations and confirmation of non-infectious nature of uveitis, 18 eyes of 10 patients underwent intravitreal injection of 4 mg triamcinolone acetonide. Changes in intraocular inflammation, bestcorrected visual acuity [BCVA], intraocular pressure [IOP] and macular thickness on optical coherence tomography were assessed during six months of follow-up. Mean BCVA increased from a baseline value of 0.81 +/- 0.29 to 0.35 +/- 0.33 LogMAR one week and to 0.17 +/- 0.07 LogMAR one month after the injection, respectively [P<0.001]. It decreased thereafter to 0.46 +/- 0.3 LogMAR at the sixth month visit, but was still significantly greater than the baseline value [P<0.001]. Mean IOP reached its maximum level one month post-injection with an increase of 7.36 +/- 0.48 mmHg compared to the baseline value, however only two eyes had IOP>22 mmHg which were successfully controlled using topical IOP-lowering medication. Mean central macular thickness decreased from 339.8 +/- 24.1 microm to its minimum value [197.18 +/- 12.7 microm] one month after the injection [P<0.001] and then increased to 203.57 +/- 9.06 microm at sixth month visit, still less than the baseline value [P< 0.001]. Intravitreal injection of triamcinolone acetonide in chronic refractory uveitis improves visual acuity and decreases central macular thickness which is sustained for at least six months. The only noticeable complication, transient IOP elevation can be controlled with topical medications

[Frequency and severity of retinopathy of prematurity: singleton versus multiple-births]

To determine the frequency and severity of retinopathy of prematurity [ROP] among singleton and multiple-birth neonates referred to Farabi Eye Hospital, Tehran-Iran. We reviewed the records of 99 consecutive neonates from multiple-gestation pregnancies including 68 twins, 26 triplets and 5 quadruplets who were screened for ROP during 2002-2004. The frequency, severity and risk factors of ROP were determined. The results were compared with a group of singletons who did not differ from the multiple-birth group regarding birth weight, gestational age, oxygen therapy, respiratory distress syndrome, transfusion, sepsis, phototherapy and gender. ROP was present in 12.1% of multiple-birth neonates compared to 15.1% in singletons [P=0.53]. Threshold ROP was present in 6.1% of multiple-birth neonates and 7.1% of singletons [P=0.62]. ROP was detected in 60% of quadruplets vs 9.6% of twins and triplets with threshold disease in 40% of quadruplets compared to 4.2% in twins and triplets. Logistic regression analysis revealed no statistically significant differences in frequency and severity of ROP among subgroups of multiple-gestation pregnancies [P= 0.79]. The higher frequency of ROP among multiple-birth neonates is due to lower birth weight and gestational age but there is no significant difference between multiple-births and singletons in terms of frequency and stages of ROP. Screening for ROP in multiple pregnancy births may be conducted according to the same standard protocols as for singletons

[Prevalence and risk factors of retinopathy of prematurity in very low birth weight or low gestational age infants]

To determine the incidence of retinopathy of prematurity [ROP] and to evaluate the possible neonatal risk factors for ROP. This cross-sectional study included all premature infants born at hospitals affiliated to Tehran Medical University, Tehran-Iran who were referred within 4-6 weeks after delivery to Farabi Eye Hospital from 2004 to 2005. Inclusion criteria were birth weight [BW] < 1500 g or gestational age [GA] 32 wk who may be at high risk for ROP should also be screened

Vitrectomy for diffuse refractory diabetic macular edema associated with a taut premacular posterior hyaloid

To evaluate the anatomic and visual results and complications of vitrectomy in eyes with diffuse refractory diabetic macular edema associated with a taut posterior hyaloid. This prospective interventional case series was conducted in 25 eyes of 22 patients with diffuse clinically significant diabetic macular edema, macular thickness greater than 250 microns on optic coherence tomography [OCT] and thickened posterior hyaloid. Best-corrected visual acuity [BCVA] and macular thickness measured by OCT were evaluated preoperatively and 3 and 6 months postoperatively. Macular perfusion was evaluated by fluorescein angiography, preoperatively. Mean BCVA was 1.14 +/- 0.51 LogMAR, preoperatively and 0.89 +/- 0.53 LogMAR 6 months postoperatively [P=0.005]. Mean preoperative macular thickness was 506 +/- 121.9 micro m which decreased to 318 +/- 90.5 micro m, postoperatively [P=0.001]. Vitrectomy with removal of the posterior hyaloid membrane appears to be beneficial in some cases of diffuse persistent diabetic macular edema with a taut premacular posterior hyaloid unresponsive to laser therapy. Careful selection of eyes with favorable preoperative clinical characteristics may improve surgical outcomes

[Comparison of the effect of different temperatures of water on dimensional accuracy of Bayer and Iralgin alginate]

Alginate is the common impression material in dentistry and its preparation with water in various temperatures is required in some instances. Does the temperature of water affect on dimensional accuracy of alginate is the question of studies? The aim of this study was to compare the effect of different temperatures of water on dimensional accuracy of stone models in impression with Iralgin and Bayer alginate. In this experimental study, one laboratory model was used with two metallic dies and alginate impression materials [Iralgin and Bayer]. Sixty impressions were taken at temperatures of 8 degree C, 23 degree C and 28 degree C for Iralgin and Bayer alginate and stone models were poured. Five dimensions of 60 models including height and diameter for each die and distance between the dies were measured by digital caliper and compared with laboratory model by the use of ANOVA and t tests and LSD analysis. Temperature change of water had statistically significant effect on dimensional accuracy of stone model. At 8 degree C, all dimensions of Iralgin and Bayer increased. There was statistically significant changes [p<0.05] in diameter and external distance between the two dies for Iralgin and in diameter of small die for Bayer. At 28 degree C, all of the dimensions of the dies decreased, that in Bayer except for the diameter of the large die and in Iragin only for small die, the difference was statistically significant. The results of this research showed that at 23 degree C temperature of water, Bayer alginate was more accurate than Iralgin alginate. At 28 degree C, Iralgin and at 8 degree C, Bayer alginate was the most accurate

[Chorioretinitis sclopetaria: a case report]

To present a case of chorioretinitis sclopetaria with attached retina in spite of performing deep vitrectomy without retinopexy. A 10-year-old boy was referred due to air-gun injury to the left eye. Right eye had visual acuity of 20/16, MG, and normal slit lamp examination and fbndoscopy. In the left eye, visual acuity was count fingers at 50 cm, MG[+++], anterior segment examination revealed massive subconjunctival hemorrhage and chemosis. On B-Scan echography there was a suspicious retinal detachment. We performed standard pars plana deep vitrectomy with prophylactic band without endolaser retinopexy. The retina was attached until last follow up at 14 month. In spite of severe defects in the retina and choroid in chorioretinitis sclopetaria, retinal detachment does not usually occur due to spontaneous retinopexy and scar formation

Incidence and risk factors of Retinopathy of prematurity

To determine the incidence of retinopathy of prematurity [ROP] and to evaluate the possible neonatal risk factors for ROP among premature infants referred to Farabi Eye Hospital during 2000-2002.Newborn infants with gestational age [GA] 37 wk or birth weight [BW] 2500 g were included. The first eye examination was performed 4-9 weeks after birth. Data on possible risk factors include low birth weight, low gestational age, sepsis, supplemental oxygen therapy, blood transfusion, phototherapy, multiple pregnancy, and respiratory distress syndrome [RDS] were compared between the two groups of newborns with and without ROP. Univariate and multivariate analysis was performed.One hundred eighty five neonates were included in this study [110 male, 75 female]. Mean GA +/- SD was 31.64 +/- 2.67 wk and mean BW +/- SD was 1620.68 +/- 467.6 g. The incidence of ROP was 12.4% [95%0: 7.6%-17.2%] including 8.6% in threshold and 3.8% in prethreshold stages. ROP was present in 18.6% of neonates with GA < 32 wk and 29% of neonates with GA < 28 weeks. All ROP cases had GA 5 wk. Mean GA +/- SD was 29.39 +/- 2.16 wk in the ROP group and 3196 +/- 2.58 wk in the non-ROP group. [P< 0.001] Mean BW +/- SD was 1283.48 +/- 342.84 g in the ROP group and 1668.55 +/- 464.04 g in the non-ROP group. [P< 0.001] ROP was pesent in 20.5% of neonates with BW S 1500 g. All ROP cases had BW 2000 g. There was a significant association between blood transfusion and incidence of ROP [odds ratio= 3.75, P= 0.004], RDS [OR= 3.14, 0.041], and phothotherapy [OR= 2.86, P= 0.044] based on univariate analysis. There was no significant association between oxygen therapy and incidence of ROP. Based on multivariate logistic regression analysis, low GA was the only significant factor associated with high incidence of ROP. We suggest GA < 33 wk and BW < 2000 g as the best criteria for screening of high neonates for developing ROP. These criteria deserve further investigation

Abattoirial survey on seasonal infection of sheep with tape worms in shiraz area

Little information is available about the seasonal infection rate of ruminants with tape worms in different areas of Iran. In the present study the seasonal incidence of intestinal tape worms was investigated in sheep slaughtered in Shiraz abattoir. From all 3165 investigated sheep, 148 animals [4.68%] were found to be infected with one or more tape worms. The highest infection rate was observed in summer [6.02%], spring [5.95%], autumn [4.06%] and winter [2.86%], respectively. The highest and lowest infection rate with different species of tape worms was observed as follow: Moniezia expansa: spring and winter, Moniezia benedeni: summer and winter, Thysaniezia giardi: summer and autumn, Avitellina centripunctata: winter and spring and Stilesia globipunctata: autumn and spring

Evaluation of dimensional accuracy of master models as a function of different thickness of wash impression material [rapid] in two step technique

Impression making is one of the most important steps in fixed prosthodontics. Due to contra-dictory opinions on the issue of the accuracy of silicone impression material as a function of technique, this study was carried out to assess the dimensional accuracy of master casts made by Rapid silicone material as a function of three impression techniques: with 2mm space, with 1mm space and without space for wash thickness. This experimental study was carried out by using laboratory models. Two dies [with and without undercut] served as laboratory models. 10 impressions were taken for each technique and stone models were poured. Six dimensions of 30 models [height and diameter for each die and distance between dies] were measured by digital caliper. The mean differences in measurements in stone model was compared with laboratory model. T-test and ANOVA analysis was used on statistical analysis. Impression techniques with different amount of thicknesses of wash impression material had statistical significant effect on dimensional accuracy of master models. Impression technique with 2mm of space for wash material compared to impression technique with 1mm space and without space for wash material was more preferable