Showing 166 results for Dental
Horie Fakhar Bashizade, Neda Molaei, Ali Teimoorinezhad,
Volume 26, Issue 1 (3-2013)
Abstract
Background and Aims: The Panoramic radiography is one of the routine techniques in implant imaging. Although there are some limitations with this technique, panoramic radiography is radiographic choice for basic evaluation for implant treatment. Many studies have been designed to determine magnification in panoramic images but most of them were performed on dry skulls or radiographic phantoms. In recent studies CT or CBCT are used as gold standard. The aim of this study was to determine vertical magnification of panoramic images using renovated CT sections in anterior and posterior regions of both jaws.
Materials and Methods: 30 panoramic radiographs (Planmeca EC or CC Proline) were selected from patients of implant department and Particular anatomic landmarks were selected in those images. Vertical dimensions of these landmarks were measured in both panoramic and renovated cross sectional CT images by a digital caliper and vertical magnification was calculated as the ratio of image dimensions to the real dimensions.
Results: The mean vertical magnification of panoramic radiographs in anterior and posterior maxillae were 1.22±0.02 and 1.16±0.02, respectively. The mean vertical magnification of panoramic radiograph in anterior and posterior mandible were 1.20±0.02 and 1.13±0.02, respectively. The differences between magnification in mandible and maxillae were significant (P<0.001). The differences between magnification in anterior and posterior regions of both jaws were not significant (P=0.11).
Conclusion: Vertical magnification of panoramic images (Planmeca EC or CC Proline) in different regions in both jaws were between 1.13 to 1.22.
Ayob Pahlavan, Masumeh Hasani Tabatabaei, Sakineh Arami, Mohammad Ataie, Sara Valizadeh,
Volume 26, Issue 1 (3-2013)
Abstract
Background and Aims: Polymerization shrinkage in Methacrylate-based composite is one of the most important factors in composite restorations failure. Silorane-based composite is introduced to compensate this drawback and claimed to have low shrinkage. The aim of this study was to evaluate the polymerization shrinkage of these two composites.
Materials and Methods: In this experimental study, 5 disk shape samples for each resin composites were placed in the centre of metallic ring bonded to microscopic glass slab. Top surface of ring was covered by a glass cover slip. Glass slab and sample were placed on a special LVDT holder in order to light cure from bottom surface and to measure the polymerization shrinkage. In this study, Deflecting Disk method and LVDT (linear variable differential transducer) was used for dimensional change measurement of resin composites. In this study, two LED curing units were used for composite polymerization.
Results: The mean of polymerization shrinkage in Z250 cured with LED and High Power LED was 11.15±0.08µm and 11.51±0.17µm, respectively (P=0.094), and in P90 cured with LED and High Power LED was 1.08±0.06µm and 1.16±0.12µm, respectively (P=0.019).
Conclusion: Silorane-based composite (P90) showed significantly less polymerization shrinkage than that of methacrylate-based composite (Z250). For the two types of composite, there was no significant difference between the two curing units in polymerization shrinkage.
Ayob Pahlevan, Tabassom Hooshmand, Mansoreh Mirzaie, Hoda Safaie,
Volume 26, Issue 1 (3-2013)
Abstract
Background and Aims: The purpose of this in vitro study was to assess the effect of two different surface treatments on the contrast ratio of IPS e.max press ceramic submitted to accelerated aging.
Materials and Methods: Ten ceramic (IPS e.max Press) disks (10-mm diameter and 1.5-mm thick) were fabricated according to the manufacturer's recommendations. The samples were randomly divided into 2 groups (n=5): polishing and glazing. Contrast ratio ware obtained with a spectrophotometer before and after accelerated aging. The contrast ratio (CR=Yb/Yw), was defined as the ratio of illuminance (Y) of the test material when it is placed on the black background (Yb) to the illuminance of the same material when it is placed over a white background (Yw), was determined. The data were statistically analyzed by two-way analysis of variance (P<0.05).
Results: All specimens of IPS e.max press ceramic showed significant increase in CR after 300-hour accelerated aging time (P=0.005). Polished samples showed significantly higher opacity compared with that of the glazed ones (P=0.018).
Conclusion: Within the limitations of this study, it may be concluded that the glazed specimens showed higher stability in their translucency than the polished specimens.
Sakineh Nikzad, Abbas Azari, Mani Arashrad, Ghazal Arashrad,
Volume 26, Issue 1 (3-2013)
Abstract
Background and Aims: The marginal integrity of fixed restorations always is a major matter of concern for dental clinicians. Any cause of distortion, including veneering processes, in the marginal integrity is supposed to be detrimental for long-term success of fixed dental prostheses. The aim of this in vitro study was to compare the marginal adaptation of two different full ceramic restoration systems (Zirkouzahu&Cercon) and possible changes in marginal integrity following the multiple veneering process.
Materials and Methods: Twelve all-ceramic crowns in the form of coping were fabricated on a pre-made standard metal die with finish line of shoulder preparation from two commercial systems: Cercon® and Zirkonzahn®. The specimens were not cemented. The Crown/Die discrepancy were measured by means of a precise stereo microscope (accuracy±0.1 μm), at various points (n=12) selected along circumferential margin of the restorations. Same procedure was accomplished after applying the veneering porcelain. The mean gap dimensions were calculated and data were analyzed by multivariate (b) test.
Results: Mean marginal gap dimensions before and after veneering porcelain firing cycles, for Cercon® were (59.67±13.46 µm) and (63.75±14.16 µm) and for Zirkonzahn® were (65.81±24.37 µm) and (64.74±21.94 µm), respectively. Hotelling trace Multivariate(b) test method showed that the rate of mismatching marginal integrity in two groups (Cercon® and Zirkonzahn®) had no significant difference before and after porcelain firing (P>0.05).
Conclusion: Within the limitation of this study, the marginal integrity of both systems were seems to be within the clinically acceptable standard dimension, i.e. 120μm.The marginal gap of both all-ceramic systems were not affected by veneering porcelain firing cycles.
Mahsa Mansouri , Khoroushi Maryam ,
Volume 26, Issue 3 (8-2013)
Abstract
U ntreated caries are common findings in low-income communities. Treatment of dental caries in young children is challenging and requires a high skill and high cost of dental anesthesia for control ling patients and thus, chemical methods for arresting dental caries have been proposed. Silver Diamine Fluoride (SDF) is a material that is used to control and to arrest dental caries , especially in primary teeth . It is noninvasive, safe , easy to use , and cost-effective. The SDF can be used as a therapeutic agent in oral health projects in low-income communities . In this article we review ed the silver diamine fluoride and its application in dentistry.
Afsaneh Pakdaman, Ahmad Khormali, Ahmad Reza Shamshiri,
Volume 26, Issue 4 (1-2014)
Abstract
Background and Aims: One of the important aspects for evaluating an organization is assessing the level of satisfaction of the clients. This study was conducted to compare the level of satisfaction between traditional and new methods of delivering dental care in the clinic of Tehran University of Medical Sciences.
Materials and Methods: A cross-sectional study was conducted on 308 patients received dental care at the dental clinics of Tehran University of Medical Sciences in spring 2010. Data were collected from Comprehensive Care Unit (CCU) in addition to 7 isolated clinics including restorative, periodontics, endodontics, radiology, and prosthodontics (fix and removable) using translated version of the Dental Satisfaction Questionnaire (DSQ), consisted of 19 questions in three main domains in addition to demographic questions. Descriptive statistics was used as percentage of answers. In order to compare the mean score between domains ANOVA test was used.
Results: The standardized mean scores in each domain were: pain control 58±17, access 59±12, quality 68±11 and total Dental Satisfaction Index (DSI) score of 62±10. 92.5% of the respondents reported that students were very careful when examining their patients. 96.8% reported that they treat their patients with respect . The most common reasons for dissatisfaction apart from waiting time and getting appointments were not providing preventive care and pain control.
Conclusion: The results of this study shows acceptable level of satisfaction with dental care in teaching clinics of this dental school, however efforts on implementing preventive care and pain control strategies are suggested.
Mohamad Reza Khalili, Babak Ziaie, Mahmoud Kazemi,
Volume 26, Issue 4 (1-2014)
Abstract
Background and Aims: Dental implants have been studied for replacement of missing teeth for many years. Productivity of implants is extremely related to the stability and resistance under applied loads and the minimum stress in jaw bone. The purpose of this study was to study numerically the 3D model of implant under thermal loads.
Materials and Methods: Bone and the ITI implant were modeled in “Solidworks” software. To obtain the exact model, the bone was assumed as a linear orthotropic material. The implant system, including implant, abutment, framework and crown were modeled and located in the bone. After importing the model in Abaqus software, the material properties and boundary conditions and loads were applied and after meshing, the model was analyzed. In this analysis, the loads were applied in two steps. In the first step, the mechanical load was applied as tightening torque to the abutment and the abutment was tightened in the implant with 35 N.cm torque. In the second step, the thermal load originated from drinking cold and hot water was applied as thermal flux on the ceramic crown surface in this model.
Results: Thermal analysis results showed that the thermal gradient in the bone was about 5.5 and 4.9 degrees of centigrade in the case of drinking cold and hot water respectively , although the maximum gradient of the whole system was reduced to 14 degrees, which occurred, in the crown by drinking cold water.
Conclusion Thermal stresses were so small and it was because of the low thermal gradient. Maximum stresses occurred in the abutment were due to the tension preloads which were originated from the tightening torque.
Mahmod Kazemi, Saeed Nokar, Ahmad Rohanian, Adel Pazhohan,
Volume 26, Issue 4 (1-2014)
Abstract
Background and Aims: Thermal changes in the oral cavity can be transferred to the implants placed in bone and affect the prognosis of the treatments. Furthermore, some investigators proposed improvement of habitual consumption of hot or cold beverages. The aim of the present study was to measure the effect of temperature changes in the oral cavity following consumption of hot and cold drinks on the temperature of implant.
Materials and Methods: In this clinical trial, 3 eligible patients were selected. Two months after implant insertion, temperature of the implants was measured following the drinking of hot and cold beverages using a sensor connected to a thermometer. The thermal changes of the implants through the different time intervals were analyzed using Friedman non-parametric test.
Results: The implant temperatures were significantly increased in the time following drinking of the hot beverages (P=0.009). Furthermore, the implant temperature were statistically decreased in the time after drinking cold beverage (P=0.004). When drinking hot beverages, the maximum and minimum temperatures were 41.57 0 C and 36.77 0 C, respectively. The maximum and minimum temperatures of the implants were also 34.13 0 C and 26.83 0 C , respectively, when drinking cold beverages.
Conclusion: It seems that the temperatures noted in the implants in the current study cannot weaken the prognosis of implant restorations however, habitual consumption of hot and cold beverages can lead to debilitating implant prognosis and therefore, should be given the necessary warnings to patients.
Mojgan Paknejad, Yadollah Soleimani Shayesteh, Zahra Nasr Esfahani, Nina Rezomeh, Mohadeseh Heidari, Ali Mehrfard,
Volume 27, Issue 1 (4-2014)
Abstract
Background and Aims: The increase in the number of complex implant cases has drawn the attention of researchers toward materials having bone regeneration promoting ability. Socket preservation and bone graft are recommended to minimize bone resorption. The aim of this study was to evaluate a kind of xenograft collagenic bone (osteo biol gen_oss) in socket regeneration.
Materials and Methods: This randomized clinical trial was performed in 12 cases (6 in test and 6 in control groups) with two hopeless teeth. After tooth extraction, in test group, graft material was put in sockets but in the control group the socket was healed naturally. Three months later, during implant placement the specimens from both sites were sent to a pathologist for histologic and histomorphometric evaluations. Data were analyzed using Mc Nemar and Wilcoxan sigh rank test (α=0.05).
Results: There were no significant differences between two groups in foreign body reaction, inflammation, bone vitality and percentage of bone gain. Average percentage of residual graft in test site was 6.73±1.43.
Conclusion: Osteobiol gen_oss xenograft is an appropriate biocompatible osteoconductive material that promotes bone regeneration at 3 months following socket preservation in human extraction sockets.
Hadi Asgharzadeh Shirazi, Mohammadreza Mallakzadeh,
Volume 27, Issue 2 (6-2014)
Abstract
Background and Aims: Hydroxyapatite coating has allocated a special place in dentistry due to its biocompatibility and bioactivity. The purpose of this study was to evaluate the relation between the hydroxyapatite thickness and stress distribution by using finite element method.
Materials and Methods: In this paper, the effect of hydroxyapatite coating thickness on dental implants was studied using finite element method in the range between 0 to 200 microns. A 3D model including one section of mandible bone was modeled by a thick layer of cortical surrounding dense cancellous and a Nobel Biocare commercial brand dental implant was simulated and analyzed under static load in the Abaqus software.
Results The diagram of maximum von Mises stress versus coating thickness was plotted for the cancellous and cortical bones in the range between 0 to 200 microns. The obtained results showed that the magnitude of maximum von Mises stress of bone decreased as the hydroxyapatite coating thickness increased. Also, the thickness of coating exhibited smoother stress distribution and milder variations of maximum von Mises stress in a range between 60 to 120 microns.
Conclusion: In present study, the stress was decreased in the mandible bone where hydroxyapatite coating was used. This stress reduction leads to a faster stabilization and fixation of implant in the mandible bone. Using hydroxyapatite coating as a biocompatible and bioactive material could play an important role in bone formation of implant- bone interface.
Narges Dorri, Azita Kaviani, Ali Noori,
Volume 27, Issue 2 (6-2014)
Abstract
Background and Aims: The ability of composite restorations to prevent microleakage needs desirable bonding material for proper sealing . The purpose of this study was to evaluate class V composite restorations microleakage in premolars with/without electric current while applying variant dentin bonding in vitro.
Materials and Methods: 120 non-carious human premolars were used for this study and standardized class v cavities were prepared. The tooth roots were cut by discs at a distance of 5 mm from CEJ and pulp tissue was removed. The teeth were divided into six groups of 20. In the first group, electric current was applied, Single bond (3M ESPE, St Paul, MN, USA) with a broom motion attached to the cathode and a sponge containing bonding was used as anode. The used current was 15µA and the Single bond in the second group was used without electricity. Then two bondings PQ1 (Ultradent, Germany) and Optibond solo plus (Kerr, USA) were used with and without electricity. After adhesive application and curing the bonding agents, cavities were restored by a composite (Valux Plus). The root ends were sealed by wax and all teeth surfaces, except 1 mm around the restorations were covered with a nail varnish. The specimens were thermocycled for 1000 cycles and placed in fushin for 24 hours and were then sectioned vertically and examined under a stereomicroscope. Data were scored on a 0-4 scale based on microleakage at the gingival margins and analyzed using Kruskal-Wallis and Mann-whitney test.
Results: Based on the results, the extent of microleakage in the groups of electric current was significantly less than the groups without using the electric current (P=0.05). The lowest degree of microleakage was found in PQ1 group, and the greatest difference between the groups with and without electricity was also found in PQ1 group. Single bond and Optibond Solo Plus with electric current showed a lower degree of microleakge.
Conclusion: The result showed that use of electric current during the application of dental adhesives could reduce the extent of microleakage.
Fateme Mokhtari, Mohammad Hossein Yosefi, Ali Gharaati Jahromi,
Volume 27, Issue 2 (6-2014)
Abstract
Background and Aims: Root canal therapy is one of the most important parts of a general dentist's profession. The aim of this study was to evaluate the radiographic quality of root canal therapy performed by under graduated students at Yazd dental school.
Materials and Methods: Records of patients, who were referred to the endodontic department during 2010-2012 and treated by undergraduated students, were divided into three groups by the numbers of canals and 80 specimens from each group were randomly evaluated. For the assessment, the quality of accomplished treatments, the indices: length, taper, and density of obturation were used and the errors during root treatment were recorded. Data were analyzed using Fisher's exact test and Chi-square.
Results: According to the results, 155 (64.6%) records had appropriate filling length, whereas 55 (22.9%) were underfilled and 30 (12.5%) were overfilled. The acquired difference was statistically significant among three groups. (P<0.001). 187 (77.9%) records had adequate taper and 157 (65.4%) records had adequate density. The difference in the evaluating of taper (P=0.976) and density (P=0.879) was not significant. Totally, 39.2% of specimens had all the properties of an appropriate root canal treatment.
Conclusion: The results of the present study can be used to identify weaknesses in the treatment of different educational groups and help them to achieve a proper planning to improve the quality of endodontic treatments.
Seyed Amir Hossein Mirhashemi, Razieh Jabbarian,
Volume 27, Issue 2 (6-2014)
Abstract
The need to identify and determine the age of the unidentified dead person s or accident victims of natural disasters is clear. Also, some remedial measures in the field of orthodontics and pediatric dentistry depend on knowing the patient’s physiological age. Previous studies suggested that dental age have a good correlation with physiological age more than skeletal or o ther common methods of age determination. Among the various methods used to determine dental age , dental radiography provides wide facilities for clinicians. Being noninvasive and the ability of performing the technique on live subjects as well as simplicity and low cost and reliable results , have led researchers to investigate further on that . The formation and calcification process of teeth and changes during aging has been regarded by many, leading to introduce various methods in which the field. In this study, 36 related articles were achieved by searching PUBMED, Science Direct and Google Scholar resources and discussed. Provided what diversified means of determining age using dental radiographs is encouraged , it is recommended to be not restricted to use only one of the methods because the multilateral approach is more reliable.
Farzaneh Jabari, Javad Mohammadnejad, Kamal Yavari,
Volume 27, Issue 3 (9-2014)
Abstract
Background and Aims: In the last decade, several studies have reported the isolation of stem cell population from different dental sources, while their mesenchymal nature is still controversial. The aim of this study was to introduce the isolating methods for stem cells from human dental pulp and to determine their mesenchymal nature before differentiation.
Material and methods: One of the best sources for stem cell is dental pulp tissue. Dental Pulp Stem Cells (DPSCs) would be the most convenient source of stem cells because teeth were easy to retrieve and removed throughout life. Pulp is a specialized connective tissue including blood and lymph vessels, nerves, and the interstitial fluid. DPSCs can be found within the ‘‘cell rich zone’’ of pulp. DPSCs have been isolated for the first time in 2000 by Gronthos these cells exhibited a differentiation potential for odontoblastic, adipogenic and neural cytotypes. Gronthos isolated stem cells in 2 different methods: The enzymatic digestion method and the second was out growth, these cells could be cryopreserved in liquid nitrogen. It has also been shown that human DPSCs can be used for complex structures such as pulp or woven bone formation in vivo.
Conclusion: DPSCs originate from the cranial neural crest and have neural characteristics such as the expression of neurotrophins. Therefore, DPSCs may represent a promising source in cell therapy for neurological disorders. Characterization of these cells and determination of their potentialities in terms of specificity of regenerative response will form the foundation for development of new clinical treatment modalities, whether involving directed recruitment of the cells and seeding of stem cells at sites of injury for regeneration or use of the stem cells with appropriate scaffolds for tissue engineering solutions. Such approaches will provide an innovative and novel biologically based on new generation of clinical treatments for dental disease.
Mohamadreza Khami, Arezo Ebne Ahmadi, Mina Ahmadian, Samaneh Razeghi, Reza Yazdani,
Volume 27, Issue 3 (9-2014)
Abstract
Background and Aims: Tobacco kills 5 million people worldwide annually, according to the Health Ministry reaches this number is about 70,000 people a year in Iran. Dental professionals are in a unique position to promote smoking cessation due to the opportunity for regular interaction with their patients. The aim of this study was to investigate knowledge, attitudes, and skills of dental students at Tehran and Shahid Beheshti dental schools towards tobacco cessation counseling in dental office.
Materials and Methods: In this cross-sectional study, the target group was dental students at Tehran and Shahid Beheshti dental schools, and the sampling method was census. A questionnaire on the knowledge, attitudes, and skills towards tobacco cessation counseling in dental practice was administered to the students (n=93). Data were analyzed using T-test.
Results: The response rate was 100% (93 students participate in this program and all of them filled the questionnaire). The average score of knowledge at Tehran and Shahid Beheshti dental schools was 17.5 and 18.4, respectively (P=0.09), the average score of attitudes was 33.5 and 33.1, respectively (P=0.80). There were no significant differences between the two dental schools in these parts. The average score of skill was 11.9 and 16.6, respectively. The differences between the students of two dental schools in skill were significant (P=0.002).
Conclusion: Although the attitude of dental students at Tehran and Shahid Beheshti schools towards tobacco cessation counseling seemed to be fair, some deficiencies existed in their knowledge and skill. Dental education programs should be implemented properly in this field.
Sayar Ferena , Mortezaei Salehe ,
Volume 28, Issue 1 (5-2015)
Abstract
Background and Aims: The routine mechanical plaque control is done by toothbrush. With regard to different designs of tooth head brushes in order to better plaque removal, the aim of this study was to evaluate the effect of between teeth and cross-action tooth brush on the plaque and gingival status among dental students of dental branch-Islamic Azad University during 2012-13 academic years.
Materials and Methods: This single-blind, cross over, clinical trial was conducted on 30 subjects with mean age (23±0.9) in two groups of 15 persons . They had at least 20 teeth and had gingivitis with no history of antibiotic use in the last 3 months. Those who were undergoing orthodontic treatment, using drugs affecting the gums and having crown and bridge were excluded from the study. The first group used the cross action toothbrush and the second group used between teeth toothbrush and the subjects were asked to brush their teeth for two minutes twice a day in modified bass method and not to floss during the execution of this study. After 14 days plaque index (Turesky, Approximal plaque index) and gingival bleeding index were recorded on all teeth except third molars. After a week wash out period, second stage of the study was conducted the same as the first stage with the other kind of brush for each group. Data were analyzed using Generalized Linear Model (GLM) test.
Results: There was no statistical significant difference between two toothbrushes based on plaque index, gingival bleeding index and approximal plaque index, respectively (P = 0.29, P = 0.47, P = 0.33). In all measured indices, the treatment sequence showed no significant difference (P = 0.23).
Conclusion: There was no statistical difference between cross-action and between teeth toothbrush in reducing plaque and gingival bleeding.
Shirazi Mohsen , Darvishpour Hojat , Nateghi Reza , Mirhashemi Amir Hosein , Salari Behzad ,
Volume 28, Issue 1 (5-2015)
Abstract
Tehran University of Medical Sciences, Tehran, Iran ( mirahashemi@tums.ac.ir )
Background and Aims: Nowadays patients refer to orthodontist for issue such as dental crowding and other aesthetic problems. The aims of this study were to evaluate the relationship between some of mandibular anatomical landmarks and dental crowding in the patient with skeletal Cl II due to mandibular deficiency.
Materials and Methods: 108 cases have been randomly selected out of patients with mandibular related Cl II problem associated with lower incisor crowding, out of orthodontic patient department of Tehran university of medical sciences. ANB, SNB, mandibular discrepancy, gonial angle, Sn-Go-Gn and IMPA was evaluated out of the data. Lateral cephalograms were used for this matter. The correlation between variables was evaluated by correlation test and after reviewing the data was analyzed using Normality test, the Pearson correlation coefficient was used for normally distributed variables.
Results: Corpus-ramus length ratio had a significant relationship with dental crowding (P≤0.05) but there was no meaningful and significant relationship between other facial landmarks ( P = 0.26 ).
Conclusion: there seems to be a slight relationship between facial landmarks and dental crowding in lower incisors. But further case control and clinical studies may be helpful in achieving more reliable data.
Sara Ghadimi, Mohammad Reza Khami, Samaneh Razeghi,
Volume 28, Issue 1 (5-2015)
Abstract
Background and Aims: Despite significant decline in dental caries in recent decades, the disease remains a
public health problem especially in developing countries. In recent years combined application of laser and
fluoride has been introduced as a new caries-preventive measure. The purpose of the present study was to review
the literature on the preventive effect of combined application of laser and fluoride on the dental caries.
Materials and Methods: PubMed, Google Scholar and EMBASE databases were searched for articles published
from 1990 to November 30, 2013. Various combinations of the following keywords were used: Dental caries,
Laser, Fluoride, Fluoride therapy, Prevention and Enamel. The inclusion criteria included all levels of available
evidence. Articles published only in english language were evaluated, and unpublished data were not sought.
Results: Several studies evaluating the effect of laser alone or combined with topical fluoride to prevent dental
enamel demineralization were found. Studies assessing the combined effect were more frequently done on
permanent teeth and just a few studies were done on primary teeth. In total, most of the studies confirmed that
combined application of laser and topical fluoride has a remarkable effect in prevention of enamel
demineralization compared to application of each of them alone.
Conclusion: Laser irradiation combined with topical fluoride application seems to provide the best prevention
effect on the dental caries initiation and progression in enamel of permanent teeth. However, more experimental
and clinical studies are necessary to be done on the primary teeth in this area.
Mahmod Kazemi, Alireza Pornasrollah, Somayeh Allahyari, Hamid Jalali,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: Adequate retention has significant importance in the prognosis of implant supported cemented the restorations. Limited literature had evaluated the effect of direct wax up or use of plastic coping on the retention of these restorations. This aims of this study was to compare the retention of castings fabricated by the plastic coping and direct wax up for single crown and bridge in three implant systems.
Materials and Methods: 28 specimens of each implant systems were randomly divided into 4 groups. Groups included wax patterns for single crowns and bridges that were made from plastic coping or direct wax up. All the wax patterns were invested and casted with base metal alloy, in similar conditions. After castings were cemented to the related abutments, the specimens were subjected to a pull out force in a universal testing machine at a cross head speed of 0.5 mm/min. The load required to decement each casting was recorded and the mean values for each group were calculated. Data were analyzed using three-way ANOVA.
Results: Comparing the between systems in crowns fabricated from plastic coping, there was no significant difference between Replace and Implantium (P=0.124), but ITI had significantly lower values than that of other systems (P<0.001 Comparing the systems in crowns fabricated from direct wax up, Implantium had the greatest retention and ITI had the lowest retention (P<0/001). Comparing the bridges with both method, Replace had the greatest retention and ITI had the lowest retention.
Conclusion: Implantium and Replace system exhibited the highest retention for fabricating crowns, and bridges, respectively.
Rabbani Khorasgani Mohammad , Aliasghari Azam , Maryam Khoroushi,
Volume 28, Issue 2 (7-2015)
Abstract
Dental caries is a multi-factorial disease and the most common human infection that annually are spent millions dollars to control and treat it. Several methods have been proposed so far to control it. The most important control methods it is now include : dental hygiene, proper nutrition , fluoride therapy , the use of non- cariogenic sweeteners . Also, the use of probiotics , nanomaterials , bacteriophages , antimicrobial peptides and anti- caries vaccines can be considered as new perspective of human in the dental caries control field. In addition, the use of complementary and alternative therapies , especially herbal drug therapy recently has been considered . Demonstrating the efficacy of complementary medicine against dental caries and its use in combination with conventional medicine or trial of new methods for decline of dental caries in the future would be hopeful.
