Showing 466 results for Er
M. Lotfazar ,
Volume 15, Issue 4 (1-2003)
Abstract
Papillon Lefevre Syndrome (PLS) is a rare recessive autosomal disease, which is associated with palm and sole hyperkeratosis and early periodontium break down of deciduouse and permanent dentition. In the differential diagnosis of PLS, congenital form of palm and sole hyperkeratosis should be considered.Recently, mutation in catepesin C gene has been recognized as a genetic basis for PLS disease. In this disease, complete lack of catepesin C enzyme activity, due to the mutations on both allels, are observed. Actinobacillous actinomycetemcomitans (A.a) bacteria are presented as the main periodontal pathogene in PLS disease. The treatment results have been contradictory and no agreement has been obtained in this regard. Elimination of A.a bacteria and administration of synthetic retinoids are reported as a suitable treatment.
Sa. Miremadi , Ar. Rokn , A. Nikbakht ,
Volume 15, Issue 4 (1-2003)
Abstract
In the past two decades, replacement of the missing teeth with implant borne prosthesis has become a treatment modality, accepted by the scientific community for fully and partially edentulous patients. The aim of the present study is to evaluate retrospectively, 502 ITI dental implants application, in partial and complete edentulous patients, treated in two private centers, based on clinical and radiographic parameters.One hundred and forty patients, with 502 ITI dental implants, who were treated from 1994 to 2000 in two private centers, were investigated. For such patientsT a minimum of one year and a maximum of six years were passed since prosthesis placement over implants, so they were cooperative subjects. There was a significant relation between implant type and bone loss, so was between the presence and absence of BOP and the rate of bone loss. From totality 502 implants, 6 implants (28%) and 4 implants (1.4%) were lost, in maxilla and mandible, respectively. The total success rate was 98%. This rate, in maxilla with 212 implants was 97.2% and in mandible with 90 implants was 98.6%. The mean value of bone loss (RBL) and periodontal pocket depth (PPD) during 6 years, for the remaning 492 implants were 0.93±0.39mm and 1.99mm, respectively. The results showed that ITI dental implants, with a success rate of more than 97%, can be used as a desirable treatment choice in partial and complete edentulous patients.
B. Ajami , N. khadem ,
Volume 15, Issue 4 (1-2003)
Abstract
Determination of puberty age of girls have been the research subject of researches and jurisprudents. The aim of this study was to investigate the relationship between tooth eruption and puberty in 12 year - old girl students. This cross-sectional study was conducted on 300, 12-year-old girl students in Mashhad, selected randomly. For each subject, a questionnaire was completed, including the information about the eruption rate of the teeth number 3,4,5,7 and the first menstruation, as puberty index to analyze the results, Mann Whitney test was used. The results of this study showed that, from among 300 female students, just 25% of them attained puberty at the age of 12.On the other hand, a direct relationship was observed between puberty and complete eruption of the second right maxillary molar and the first and second left mandibular premolars, which was statistically significant.
F. Baghaie Naeini , E. Yazdi , M. Seyed Majidi ,
Volume 15, Issue 4 (1-2003)
Abstract
The differential diagnosis between pleomorphic adenoma, the most common salivary gland neoplasm, microscopically, and two other common salivary gland neoplasms, meaning adenoid cystic carcinoma and mucoepidermoid carcinoma, is difficut.The purpose of this study was to determine the differences between pleomorphic adenoma, adenoid cystic carcinoma and mucoepidermoid carcinoma regarding the staining intensity with PTAH and H&E and also to investigate the relationship between staining intensity with PTAH and malignancy grade in mucoepidermoid carcinoma. 72 paraffin embeded samples including 24 pleomorphic adenoma, 24 adenoid cystic carcinoma and 24 mucoepidermoid carcinoma were selected and stained with PTAH. The staining intensity in total, in nucleus and cytoplasm of tumoral cells were evaluated and compared with H&E staining, statistically. The results were analyzed by Kruskal-Wallis, and Wilcoxon signed ranks tests (P<0.05).The logistic model was presented to predict the degree of malignancies through the assessment of nucleus and cytoplasm staining intensity in tumoral cells, and the patient's age. In this study, a statistically significant relationship was observed between staining intensity by PTAH and H& E in nucleus of tumoral cells in pleomorphic adenoma. Moreover, statistically significant relation between staining intensity by PTAH and H & E in cytoplasm of tumoral cells in adenoid cystic carcinoma was found. But there was no relation in other cases. On the other hand, a statistically significant relation between intensity of staining in total, in nucleus and cytoplasm of tumoral cells and the type of tumor was found. No relation was obtained between malignancy grade of mucoepidermoid carcinoma and staining intensity in total, in nucleus and cytoplasm of tumoral cells. The presented logistic model indicated a direct relation between tumor malignancy with patient's age and staining intensity in nucleus of tumoral cells, but a reverse relation was found between cytoplasm staining intensity in tumoral cells and tumor malignancy.Our findings show that PTAH and H & E staining methods, lead to similar results, however, PTAH staining is a reliable method in differential diagnosis of such salivary gland tumors.
L. Eslamian ,
Volume 15, Issue 4 (1-2003)
Abstract
According to researches, premolar extraction and anterior teeth retraction result in temporomandibular joint disorder due to posterior position of mandible. The aim of this study was to evaluate the effect of premolar extraction on TMJ disorder. In this interventiond study, 4 groups (10 patients for each group) were treated.They were classified as 1- non extraction, 2- extraction of two upper first premolars, 3- extraction of four first premolars, 4- combined extraction groups. Helkimo scores were evaluated before treatment, after treatment, one and two years after treatment. The results were analyzed with ANOVA and paired t-test. At the end of the treatment and two years after treatment in comparison with before treatment, Helkimo score had Significant differentce in all groups (PO.001). In the second year after debanding in comparison with the first year after debanding, no significant differences were seen in each group. No significant difference was seen between the four groups in the final appraisal of TMD. It seems that extraction had no adverse effect on TMD.
M. Zarrabian, N. Barfehi ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement of Problem: Different materials have been suggested for endodontic surgeries. One of the most important characteristics of filling materials is their biocompatibiiity.
Aim: The aim of this research was to evaluate the biocompatibiiity of four different root end filling materials.
Material and Methods: In this study, 20 male Guineanpigs from English short hair breed, weighing 600-700 grams, were selected. The animals were classified into two groups. In the first group, amalgam and composite and in the second group MTA and Glass Ionomer were examined. The testing materials were shaped into cylindrical form with 1 mm diameter and 1.5 mm height. After general anesthesia, two
cavities with 1mm diameter and 2 mm depth were prepared in parasymphysis area of animal jaw. The prepared materials were implanted in these cavities and the flaps were sutured. After 80 days, the animals were sacrificed and the dissected bones, with implanted materials inside them, were sent for histological evaluation. The histological findings were statistically analysed by Kruskal Wallis and x'tests.
Results: No significant differences were shown in the degree of inflammation, the type of inflammatory cells adjacent to the tested materials and the type of tissue response, induced in the vicinity of these four materials during 80 days.
Conclusion: Regarding biocompatibiiity, there was no significant difference among amalgam,composite, MTA and glass Ionomer in endodontic surgeries.
M. Ghavamnasiri , Saa. Hosseini , H. Farzaneh ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement Problem: A few studies have been conducted about bioglass posts.
Aim: The aim of this study was to compare bioglass posts with prefabricated metallic posts in clinical performance of extensive composite restorations for anterior endodontically treated teeth.
Materials and Methods: Sixty endodontocally maxillary anterior teeth, with horizontally or vertically destruction, were selected. Teeth were divided into two groups based on the kind of post: Metallic prefabricated parapost and bioglass post. Each group was divided into three subgroups based on anterior bite: normal, deep bite and edge to edge. Gutta-percha was removed from 2/3 of canal length for parapost and 1/3 for bioglass post. After etching with phosphoric-acid (37%) and applying dentine bonding syntac, Duo cement was used for the adhesion of bioglass post and a self cured composite (Degufil) for parapost. Restoration was done with a hybrid composite (Heliomolar). Follow up studies, radio-graphically and clinically, were done every three months for a 1.5-year period. Exact Fisher and Pearson tests were used for data analysis.
Results: Apical lesion was not observed in any of the radiographs. Post seal was increased by resin cement and dentin bonding agent. Post type did not significantly affect on the clinical success rate of the restorations. The retention of restoration, for both posts, was the same. Crown destruction had no significant effect on success rate. The type of anterior bite had a significant effect on success rate, as the total 6.6% failure rate was related to the patients with anterior deep bite.
Conclusion: It is suggested to use metallic paraposts and bioglass posts, in extensive composite restorations for patients with deep-bite, more conservatively.
Z. hedayati , S. Sang ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement of Problem: Cephalometric findings are of high importance in making decision about orthodontic treatment plans and orthognathic surgeries. Natural head position (NHP) is considered as a useful and exact radiographic technique.
Aim: The aim of the present study was to compare two techniques, namely Standard and NHP, in lateral cephalometry.
Materials and Methods: In this cross- sectional study, performed in Shiraz. 138 randomly selected students {70 males .and 68 females), age ranging from (13-15). were evaluated clinically and radiographically. None of them had a history of orthodontic treatment, head and face fracture or surgical operations. Lateral cephalograms were taken in both standard and natural head position techniques, for each student. For statistical analysis, l-lest for paired samples, was done.
Results: This study showed that in anterior-posterior dimension, among angles with significant differences in two techniques, those of standard one were more reliable, whereas in vertical dimension.statistical differences showed natural technique as more useful one.
Conclusion: Due to the fact that natural cephalometry requires more patient cooperation, more time and a higher complex technique, it is not suggested, except when different clinical and cepholomeiric findings are observed.
M. Ghandehary- Motlagh , P. Farajy ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement of Problem: Central crown fractures of deciduous and permanent teeth lead to unfavorable psychological effects on both children and their parents. Moreover, it can cause malocclusion. So,recognizing tooth fracture reasons plays an important role to prevent its side effects.
Aim: The aim of this study was to investigate the reasons' of permanent central crown fractures in (7-12)years old children.
Materials and Methods: Records of 218 children, with at least one central tooth fracture, referred to pediatric department of faculty of dentistry of Tehran University of Medical Sciences, from 1999 to 2000, were studied. All the related information about fracture such as: reason, location, time, type of occlusion, and type of fracture were recorded.
Results: It was found that falling down (45.4%) and having contact with external objects (21.6%) were the main reasons for permanent centrals fractures. The mean age of these children was 9.78±1.24 and 63.3% of them were boys. It should be noted that 41.3% of them had unsupported lip. The highest rate of fractures belonged to upper centrals. Based on Ellis classification, most fractures were of degree 3 (52.7%). There was no significant relationship between overbite and overjet with the degree of fracture (P<0.05).
Conclusion: Dental skeletal malocclusions such as CI II, Div I, central incisors protrusion and developmental defects of tooth structure should be considered as determinant factors in tooth crown fractures.
Sh. Alavi , A. Safari ,
Volume 16, Issue 1 (4-2003)
Abstract
Statement of Problem: Anthropometry is applied in medical professions such as maxillofacial surgery,growth and development studies, plastic surgery, bioengineering and non- medical branches such as like shoe- making and eye- glasses industries.
Aim: The aim of the present study was to determine facial and cranial ratios among Isfahan young adults.
Materials and Methods: A study was done randomly on 200 boys and 200 girls, from among Isfahan young adults, with normal face patterns. Facial and cranial ratios, according to sex, were estimated and compared.
Results: The results of this study were compared with Canadian anthropometric findings by Farkas.There was no significant difference in cranial width between boys and girls but cranial length and all facial parameters (Int ,cant, go-go, zy- zy, ch-ch, Ala-Ala, low.lip, Up.Iip, Sn.gn, Sto.gn, N.sto, Ngn)were greater in boys than girls. Cranial index and , , " ,Cl ratios were greater in n - gn zy - zy zy - zy zy - zy ... slo-go sn-gn sto-gn slo-gn sto-gn . . ._girls, however, -, -, , , were greater in boys, There was no significant go-go n- gn n- gn n- sto sn - gn difference about facial index between boys and girls. Comparing facial parameters between Iranian and Canadian races, low. lip, Ala-Ala and go- go were greater among Iranians, however, Int cant ,Up. lip. N.gn, ch- ch, zy-zy showed a greater size among Canadians. Sn-gn ratio was greater in Canadian girls, but there was no significant difference between Iranian and Canadian boys in this regard. " " s" , s° " 8° , " ~ s ° , g° " 8° , ^-- ratios were greater among Isfahanian boys and girls,zy-zy zy-zy zy-zy n - gn zy-zy however, J ° ~ g" , 5 ° " 8" / ° " s" ratios were greater among Canadians. Regarding 5"~g" ratio, no n- sto sn- gn n~ gn n- gn significant difference was observed between Canadian and Isfahanian girls.
Conclusion: Considering the significant difference in the facial and cranial anthropologic ratios and sizes, among Canadian and Isfahanian young adults, the results obtained from Canadian race, should not be applied as a criteria for Iranian surgical and dental treatment plans. Due to the wide racial combinations in Iran, more studies, with wider variations, should be conducted among different Iranian races.
J. Koiahi-E-Kazerani , P. Ghalyani Isfahani , J. Varshosaz ,
Volume 16, Issue 2 (5-2003)
Abstract
Chlorhexidine is bonded well to the oral mucosa and dental pellicle and is poorly absorbed from the astrointestinal tract, but in high concentration it is absorbed enough to produce liver necrosis. In this case a dentistry student accidentally ingested a shot of 20% chlorhexidine gluconate solution. Treatments included washing the oral cavity with lots of tooth paste, drinking of 5% alginate syrup and ingestion of 5g small pieces of cork .The following adverse effects were experienced: headache, giddiness, mild mist, euphoria, stomachache, diarrhea and complete loss of taste sensation for 8h, which recurred gradually during the last 48 hours. According to the poor absorption, low toxicity and low concentration of conventional mouthwashes, systemic toxicity following drinking of some shots of this solution is rare. Ultimately if may cause gastritis. Other treatments which are helpful in the same cases are: drinking of hard water, kaolin and tragacant syrup, bicarbonates such as baking soda, carbonates such as beverage , citrates such as lemon-juice and chlorides such as brine and so on.
M. Paknegad , A. Miremadi , M. Tabatabaei-E-Yazdi , M. Khodadad-E- Motarjemi ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: The correlation between the activity of aspartate aminotransferase (AST) and alkaline phosphatase (ALP) enzymes in gingival sulcular fluid (GCF) with inflammation and periodontal attachment loss has been proved, however there are not adequate studies about dental implants.
Purpose: The aim of present study was to investigate the presence and activity level of AST & ALP and their correlation with pocket depth (PD) and bleeding of peri-implant slcular fluid (PISF), and to evaluate the possibility of using these assessments as a diagnostic index in oral implantology.
Material and Methods: In this study, 41 implants as test group and 41 contralateral teeth as control group, in 21 patients were evaluated. At first visit, the general information about implants and the values of pocket probing depth (PPD), modified sulcus bleeding index (mSBl) and modified plaque index (mPI) were recorded. At the second visit, samples of GCF/PISF were collected. AST & ALP activity was determined spectrophotometrically and data were analyzed by "t", "Mann-Whitney" tests and Pearson Spearman correlation coefficient.
Results: The results showed that there was a significant difference in the activity of AST between two study groups (P<0.0001). The average activity of ALP in test group was more than control group but the difference was not significant. After elimination of the confounding variables, the average AST in test group was 54.6 (S£=2.3) and in control groups was 44.8 (SE=2.3) (P=0.004). The average ALP in test group (SE=2.2) and in control (SE=2.2) were 36.6 and 35.4, respectively. Values of AST and ALP were positively correlated with other clinical parameters such as PD and mSBI which was significant in test group.
Conclusion: The present study suggests that PISF analysis could be considered as a proper diagnostic strategy in the evaluation of dental implant success.
H. Afshar , B. Seraj , A. Emadosadati ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: Previous experiences and clinical observations indicate that enamel hypoplasia and hypocalcification of first permanent molars, among infants born in Cessarian Section Delivery (C/S) is more common than those born in Normal Vaginal Delivery (NVD). Moreover, the first permanent molar is the only tooth that its "cusp tip calcification" starts exactly at the time of delivery.
Purpose: The aim of this research was to investigate the relationship between delivery type and clinical feature of the first permanent molar. Meanwhile, the different effects of the elective and selective types of cessarian, on the clinical feature of first permanent molar, were studied.
Materials and Methods: Birth files, relation to the year 1994 and before, were extracted from a gynecologist clinic. One hundred patients with NVD, 50 patients with selective cessarian delivery and 50 patients with elective cessarian delivery were chosen to examine clinical feature of the first permanent molars of their children. The children, 6 years old or more, were examined. The medical information of the mother were extracted from her file and that of child, were asked from the mother. To analyze the result, X lest- was used.
Results: The prevalence of enamel defects (hypoplasia and hypocalcification) of the first permanent molar among children born by C/S, were significantly different from the children born by NVD (P=0.0002). Mean while, the prevalence of these enamel defects in the selective cessarian delivery was more than elective cessarian delivery (17% vs. 9%), which was not statistically significant (P-0.07)
Conclusion: It is suggested that gynecologists, pediatricians and pedodontists provide the parents with necessary information about the child's first permanent tooth and ask them to pay enough attention to keep this tooth which is considered as the key of occlusion.
M. Hassani Tabatabaei , M. Ataei , H. Safar Charati ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: Recently, investigators have presented new methods to reduce polymerization shrinkage of composite resin restorations. It is claimed that more powerful light cure systems associated with a change in radiation patterns, lead to improved mechanical properties and reduced microleakage.
Purpose: The aim of the present study was to evaluate the effects of two curing systems, known as Soft-Start, Pulse-Delay, on microleakage and degree of conversion of composite resin restorations.
Materials and Methods: To evaluate microleakage, dye penetration method in class V cavities was applied. 30 extracted human molars filled with three different curing techniques, namely conventional, Soft-Start and Pulse-Delay, were compared. Degree of conversion was measured by FTIR Spectroscopy method immediately after sample curing. Kruskal- Wallis and Mann-Whitney test were used to compare groups.
Results: The degree of microleakage in enamel and dentin among three groups was not significantly different, however, microleakage in gingival and occlusal walls showed a significant difference among Pulse-Delay curing (P=0.001) and Soft-Start curing (P=0.28) groups, meaning that leakage gingival in wall was significantly higher than occlusal wall. This difference was not significant in conventional group. Moreover, the degree of conversion was not statistically significant among three groups (P-0.909).
Conclusion: Soft-Start and Pulse-Delay curing systems, with a two intensity start curing light, do not provide better marginal adaptation in class V composite resin restorations. It should be mentioned that polymerization degree is not also reduced in these methods.
P. ghalyani Isfahani , Sa. Keyhan , A. Shirani ,
Volume 16, Issue 2 (5-2003)
Abstract
Statement of Problem: Ultrasonic Scaling is one of the main sources of producing infected aerosols in dentistry. These aerosols are able to spread pathogens such as microorganisms associated with tuberculosis, conjunctivitis, influenza and other respiratory diseases, herpetic and other skin diseases, ADIS and hepatitis B.
Purpose: The aim of this study was to investigate the clinical effectiveness of an aerosol- reduction device attaching to ultrasonic scaler handpiece.
Materials and Methods: In this experimental study 18 patients participated. Randomly, mandibular and maxillary quadrants of one side, in each subject, were scaled using an ultrasonic scaler with aerosol-reduction device for 5 minutes. After 30 minutes, another quadrant was scaled by ultrasonic scaler without aerosol- reduction device. In order to determine the effectiveness of aerosol- reduction device, blood agar plates attached to the surgical mask of the operator, 30 cm far from the patient's mouth, were incubated in 37°c for three days and the colonies were counted. Median, Interquartile eange and Wilcoxon test, at the 0.05 level of significance, were used to analyze the data.
Results: The median and interquartile range for the number of colony forming units (CFUS) without aerosol- reduction device was 17.5 (8, 24), while the median for the number of CFUS when using aerosol-reduction device was 0 (0, 1), indicating significant statistical difference (PO.001)
Conclusion: The aerosol- reduction device significantly reduces the amount of aerosols produced during ultrasonic scaling.
M. Pangnoosh , H . Bashizadeh Fakhar ,
Volume 16, Issue 3 (5-2003)
Abstract
Statement of Problem: Computer Sciences, in radiology, like other fields, is of high importance. It should also be noted that the accuracy of the technique and work conditions affects the radiographs information considerably. There for, in order to get more accurate diagnostic information, it seems necessary to investigate different digitized radiographic techniques and to compare them with the conventional technique.
Purpose: The aim of this study was to compare the accuracy of conventional and digitized radiographic images by three digitization techniques in proximal caries detection.
Material and Methods: In this research study, sixty extracted human canines, premolars and molars were mounted in blocks and imaged on E-Kodak film, similar to bitewing radiographs. Ten bitewing radiographs were then scanned at 600 d.p.i with flat bed scanner and a digital camera, then digitized at 300 d.p.i with another digital camera. The digitized images were displayed randomly on a high-resolution monitor. Six
observers assessed the caries status of 120 proximal surfaces by conventional and digitized images. The observer's scores were compared with the results of the macroscopic examination. Reliability of each technique was calculated. Data were analyzed using chi-square and ANOVA tests.
Results: No significant differences were detected between different techniques in intact proximal surfaces and enamel caries diagnosis. However, digital techniques were more sensitive in dentin caries detection (P<0.05).
Conclusions: When conventional film images are digitized, medium resolution (300 d.p.i) seems to be sufficient. At this resolution the file size is decreased and there is no significant loss of the information necessary for caries diagnosis.
B. Eftekhar ,
Volume 16, Issue 4 (1-2004)
Abstract
The use of root canal models in endodontics education is of high importance. So, in this article a new method is presented that the students can produce these models with simple and low cost instruments.These plastic models are made of polyester which is low cost, available and has the approximate cutting properties of dentin. The best molds were disposable syringes due to their low cost, availability and producing smooth surfaces on polyester models. A spreader with desired curve and tapering is used for producing canals. Rockwell A hardness coefficient of polyester is "33", which is near dentin "31" and foreign made models "35.5". Since these polyester models can tolerate up to 280°C and have acceptable resistance to chloroform, all root canal therapy techniques such as vertical condensation and retreatments are practicable. Their transparency encourage the students to work on them. As a result, the use of these models is recommended for endodontics training.
M. Zarabian , M.h. Nekoofar , Bs. Marashi ,
Volume 16, Issue 4 (1-2004)
Abstract
Statement of Problem:Various methods have already been suggested to measure the working length in root canal therapy among which the use of paper point, tactile sense, radiography and electronic apex finder instruments can be named. Investigations on EAL (Electronic Apex Locator) indicate that these instruments can reduce the number of required radiography to a great extent. Moreover, in special cases such as patients with high risk reflex, pregnant women, the mental disabled and handicapped and also in cases with special anatomical structures these instruments are proper substitutes for radiography.
Purpose: The aim of this study was to compare the accuracy of an Iranian made apex finder instrument with Neosono Ultima EZ and radiography.
Materials and Methods: This study was conducted on 51 mandibular molars, devoid of calcification, internal and external resorption, severe root curve or fracture, which were extracted due to periodontal disease or severe caries. All the specimens were washed in 2.5% hypochlorite sodium and washing with water, kept in 10% formalin solution, under room temperature.
Results: The accuracy of the Iranian instrument was measured (81.8%) similar to that of radiography (81.2%). But the accuracy of Neosono Wtima EZ was (92.9%) which was higher than the two other methods.
Conclusion: No statistically significant difference was found between Neosono Ultima EZ instrument and two other groups, using SPSS 10 statistical soft ware.
B. Ebadian , R. Mosharaf , M. Ebrahimi ,
Volume 16, Issue 4 (1-2004)
Abstract
Statement of Problem:Iranian product, Acropars autopolymerizing acrylic resin is nowadays widely used in dental prostheses. Dimensional change is a common problem among Iranian made acrylic resins in making custom trays and record bases, seems to be more than the similar foreign products. In order to achieve a technique for making a record base with minimum dimensional changes, more research is necessary.
Purpose: The aim of the present study was to determine a curing technique for Iranian autopolymerizing acrylic resins leading to the least polymerization shrinkage and the most adaptation between record bases and stone casts.
Materials and Methods: In this experimental study, 40 stone casts were divided into four 10- member group. For each group, polymerization shrinkage was determined at three points with one of the following techniques: Bench curing, Curing under a coat of petroleum jelly , Curing in a monomer saturated atmosphere, Curing in boiled water. Adaptation between bases and stone casts were measured at three points (the right and left crests of the ridge and the midpalatal region) with a light-measuring microscope. To analyze
the data, Variance analysis was used.
Results: The monomer atmosphere technique showed the minimum dimensional changes and the samples in boiled water group had the maximum dimensional changes. No statistical differences were observed between other groups.
Conclusion: More adaptation between record bases and stone casts was observed in monomer atmosphere polymerization technique. The differences between bench curing and curing under a coat of petroleum jelly techniques with this method were not statistically significant. Therefore, it is suggested for making base records with maximum adaptation.
O. Savabi , R. Mazaheri , S. Shadzi , F. Nejatidanesh ,
Volume 16, Issue 4 (1-2004)
Abstract
Statement of Problem:The surface topography of denture base material is an important factor for the adhesion of Candida albicans and other microorganisms.
Purpose: The aim of this study was to evaluate the adherence of Candida albicans to four types of denture base materials (Acropars acrylic resin, Meliodent acrylic resin, rough and smooth surfaces of Molloplast B).
Materials and Methods: Seven blocks of two types of acrylic resins and ten blocks of silicone with one rough and one smooth surface were made and incubated in a suspension of Candida albicans. After washing,the blocks were stained with acridine orange and examined under fluorescent microscope. For statistical analysis ANOVA and Duncan tests were used.
Results: It was observed that Candida adhesion to rough surfaces of acrylic resins and silicone was significantly more than polished surfaces of acrylic resins and smooth silicone (PO.0001). However, no
statistical significant difference was found between polished acrylic resins surfaces and smooth silicone.
Conclusion: Significant differences in the adherence of Candida to the surfaces of different denture base
materials are due to differences in surface topography, chemical, physical and hydrophobic properties so it is
recommended to minimize the roughness and irregularities of denture base.
