Showing 1049 results for Type of Study: Research
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.
Mirhashemi Amirhossein , Geramy Allahyar , Sodagar Ahmad , Baghaeian Pedram ,
Volume 28, Issue 1 (5-2015)
Abstract
The aim of this review article was to define the mechanism of action and effects of commonly used medications on the tissue remodeling and Orthodontic Tooth Movement (OTM). A review on the effects of medications and dietary supplements on the rate of experimental tooth movement was performed using Cochrane library, Embase and medline (1980-2013). 63 articles were included in this review. 34 of them were related to the effects of hormones and analgesics, were evaluated in this article but their interpretation was hindered by the variability in experimental design, magnitude of force applied during tooth movement and medication regimens. Non Steroidal Anti-Inflammatory Drugs (NSAIDs) reduced the rate of tooth movement while non-NSAIDs such as acetaminophen had no effect on the rate of OTM. Corticosteroids, parathyroid hormone and thyroxin increased the rate of tooth movement. Sturgeons might slow OTM, but experimental studies are lacking. Medications might have an important influence on the rate of tooth movement and information on their consumption is necessary to adequately discuss treatment planning with patients.
Faramarz Zakavi, Hengameh Alinejad, Zahra Jowkar,
Volume 28, Issue 1 (5-2015)
Abstract
Background and Aims: Marginal fit is one of the key factors in the success of fixed restoration. The aim of this study was to evaluate the fitness of feldespatic crowns made from additional silicon impression and gypsum cast by CAD/CAM.
Materials and Methods: 10 intact extracted upper premolar teeth were used for this experimental study. After preparation of the mounted teeth with radial shoulder finish line, 2 Vita Mark II feldespatic CAD/CAM machined crowns were fabricated for each tooth (one from scanning the additional silicone impression of the prepared tooth and the other one from the plaster model). Marginal gap of each crown was measured using SEM in two points on the mesial and 2 points on the buccal surface. Data were analyzed using Paired t-test with SPSS version 17 software (P<0.05).
Results: The mean of marginal gaps in crowns fabricated from additional silicone and model plaster were (155.13±37.11) and (130.18±12.35), respectively. However, no significant difference emerged between marginal gaps of the two methods (P=0.055). Also, the mean of marginal gaps in crowns fabricated from additional silicone and model plaster was higher in mesial (157.82±44.41) compared to buccal (127.50±24.26) region (P=0.003).
Conclusion: Marginal fit was not significantly differen ce between crown s made of the plaster casts and silicone molds and both methods showed the same results .
Kermanshah Hamid , Alhosseini Seyedeh Narges Ameri , Ghabraei Sholeh , Kharazifard Mohammad Javad ,
Volume 28, Issue 1 (5-2015)
Abstract
Background and Aims: Porcelain restorations are often ground for clinical adjustment and this removes the surface glaze layer and introduces flaws that can grow in wet environments due to stress-corrosion, reduce the strength of porcelain and limit restoration lifetime. The aim of this study was to introduce some surface treatment methods to control the flaws of ceramic restorations external surface and improve their strength.
Materials and Methods: 40 feldspathic discs were prepared and divided into 4 groups (n=10): not indented (group 1) and others indented by vickers with 29.4 N and received different treatments: no treatment (group 2), polished (group 3) and polished-silane-resin (group 4). Biaxial flexural strength of discs was tested after water storage. Data were analyzed using one-way ANOVA .
Results: The mean flexural strength of specimens in group 1 (134.49±12.60), 2 (94.81±15.41), 3 (89.20±16.22) and 4 (80.67±12.01) were measured. Group 1 (not indented) revealed significantly higher strength (P<0.001) than that of indented groups (2, 3 and 4) . There was no significant difference between group 2 (no treatment) and 3 or 4 (treated) and between treatment methods (3 and 4) (P=0.136).
Conclusion: The strength of porcelains is dependent on presence of cracks. With the limitations of this study, none of the treatment methods could strengthen the cracked ceramic.
Sharareh Mousavi Zahed, Kamal Amini, Jahromi Maryam Zare ,
Volume 28, Issue 1 (5-2015)
Abstract
Background and Aims: To ensure root canal treatment success, endodontic microbiota should be efficiently reduced. Several irrigation devices have been recently introduced with the main objective of improving root canal disinfection.The purpose of this study was to evaluate the rinsing effect of RinsEndo system in reduction of enterococcus faecalis in comparison with conventional hand syringe in infected root canals.
Materials and Methods: 60 extracted single canal anterior teeth were infected with enterococcus faecalis and divided into 3 groups: RinsEndo system, conventional hand syringe and control group. The enterococcus faecalis colonies were counted in each group before and after rinsing. Data were analyzed using Variance and Kruskal Wallis test.
Results: The mean of enterococcus faecalis growth after rinsing was 3.50×103 in group with conventional syring rinsing, 2.04×103 in group with RinsEndo washing and 6.11×103 in control group. Reduction of enterococcus faecalis after rinsing was statistically significant in each group (P<0.001). The amount of reduction in number of colonies with RinsEndo and conventional syringe rinsing was higher in comparison with control group and this difference was significant (P<0.001). RinsEndo rinsing effect was statistically significantly higher in comparison to conventional syringe as well (P<0.001).
Conclusion: Rinsing with RinsEndo system was significantly more efficient in reduction of enterococcus faecalis from root canal in comparison with hand syringe washing.
Sajjadi Farnaz Sadat , Nili Monireh ,
Volume 28, Issue 1 (5-2015)
Abstract
Background and Aims: Posterior palatal seal is one of the most important areas to support maxillary complete denture. The aims of this study was to evaluate the dimensional accuracy of both direct and indirect relining methods on the maxillary posterior palatal seal area.
Materials and Methods: A maxillary edentulous model was selected. A 1.5 mm layer of wax was placed on the model to create a space for relining material and impression was done by the silicone material and 20 casts was prepared. By putting the wax on the casts and performed of flasking, 20 dentures were prepared. Direct reline method (as Chair side with GC reline) and indirect method (with Acrosoft-TC and firing with Acropars 100) were evaluated. The relined bases were put on the model and the spaces between them in five points (two points on the ridge , two points in the deepest part of palate and one point in the middle of palate) were calculated by the Stereo microscope and each calculations was repeated 5 times and the mean dimensional changes was measured. To compare the groups, data were analyzed using multivariate analysis.
Results: The gap of P.P.S area was between 740.86 and 2356.49 . Direct method (1011.81±60.56) had a lesser gap in comparison with indirect (2056.8±13.13), and both method showed a significant statistic variance (P<0.0001).
Conclusion: Direct method showed a lesser gap in comparison with indirect method. By direct method adaptation of the denture in the P.P.S area would be better.
Hooman Zarif Najafi, Morteza Oshagh, Mohsen Azizi,
Volume 28, Issue 1 (5-2015)
Abstract
3- Dentist
Background and Aims: An attractive, well-balanced smile is a paramount treatment objective of the modern orthodontic therapy. The purpose of this study was to determine the effects of the buccal corridor size and tooth-gingival display on the smile esthetics as perceived by two groups of the students.
Materials and Methods: A colored image of a woman frontal posed smile was selected. The image was altered digitally to produce different buccal corridor sizes (6%, 12.5% and 20%) and different tooth-gingival displays (maxillary central incisors and 2 mm of gingival, maxillary central incisors and dental papilla and 80% of the maxillary central incisors). The different buccal corridor sizes and tooth-gingival displays were combined to produce 9 images. These altered images were rated by 120 medical and dental students using Visual Analogue Scale (VAS). Data were analyzed using Mann-Whitney test, Pairwise comparison LSD test, Repeated measure MANOVA and ICC (Intraclass Correlation Coefficient).
Results: The smile which had the buccal corridor size of 12.5% and complete incisor display without gingival display received the highest rates among the nine smile images in the dental students group. But in the medical students group the smile with the buccal corridor size of 12.5% and 2 mm gingival display, received the highest rates among the nine smile images. There was no significant difference in judging between the male and female raters for the both groups (P>0.05). The dental students were more critical about the increasing of the gingival display.
Conclusion: In the treatment procedure that may lead to the combination of wide buccal corridor and more tooth-gingival show, more caution should be considered.
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.
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.
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.
Baharan Ranjbar Omidi, Ladan Madani, Aida Mirnejad Joybari, Ensyeh Rashvand, Sonia Oveisi,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: Microleakage is an important problem with direct restorations and familiarity with contributing factors is of utmost importance. The aim of this study was to evaluate the microleakage of three glass ionomer restorations in class V cavities.
Materials and Methods: In this in vitro study, class V cavity preparations were made on the buccal and lingual/ palatal surfaces of 30 human premolars (60 cavities). The specimens were divided into three group (n=10, 20 cavities). Restored as follows: group1: with Fuji IX (HVGI) ionomer/G coat plus, group 2: Ionofil molar (HVGI)/ G coat plus, and group 3: Fuji II LC (RMGI) / G coat plus. All specimens were finished and polished immediately and were thermocycled (2000 cycles, 5-50°C) . In each group half of the teeth were load cycled (50000 cycles). Finally, the teeth were immersed in 0.15% basic fushine dye for 24 hours at room temperature and then sectioned and observed under stereomicroscope. Data were analyzed using Kruskal-Wallis, Man- Whitney test and a comparison between incisal and gingival microleakage was made using Wilcoxon analysis.
Results: It was shown that the mechanical load cycling and filling material did not cause a statistically significant increase in the incisal and gingival microleakage in any of groups (P>0.05).
Conclusion: It was concluded that the extent microleakage of Fuji II LC was similar to that of the highly viscous glass ionomers (Ionofil molar, Fuji IX) and load cycling did not increase the microleakage.
Amirhossein Mirhashemi, Allahyar Geramy, Ahmad Sodagar, Pedram Baghaeian, Yasamin Jalali,
Volume 28, Issue 2 (7-2015)
Abstract
Molecules produced in various diseased tissues or drugs and nutrients consumed regularly by patients, can reach the mechanically stressed paradental tissues through the circulation and interact with local target cells. The combined effect of mechanical forces and one or more of these agents may be inhibitory, additive or synergistic. The aim of this review was to outline the mechanisms of action and effects of some commonly used drugs on tissue remodeling and Orthodontic Tooth Movement (OTM). A review on the effects of medications and dietary supplements on the rate of experimental tooth movement was performed using Cochrane library, Embase and Medline (1980-2013). 63 articles were included in the review. 34 of them related to the effects of hormones and analgesics were evaluated in the first part of this review. The rest of them (29 articles) were evaluated in the current review, but their interpretation was hindered by the variability in experimental design, magnitude of force applied during tooth movement and medication regimens. Vitamin D3 might enhance the pace of tooth movement, but dietary calcium and fluorides appear to reduce the rate of OTM. Bisphosphonates (BPNs) are considered to have marked inhibitory effects on the rate of tooth movement. Nicotine and nitric oxide might effectively increase the speed of OTM. All drugs reviewed had therapeutic effects, as well as side effects, that may influence the cells targeted by orthodontic forces. Therefore, it is imperative that the orthodontist pays close attention to the drug consumption history of each and every patient, before and during the course of orthodontic treatment. When the use of drugs is revealed, their effects and side effects on tissue systems should be explored to determine their potential influence on the outcome of mechanotherapy.
Sandra Mehralizadeh, Peyman Mehrvarzfar, Sima Taghizadeh, Maryam Edalat, Mahashad Mohebi,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: Diagnosis of vertical root fractures often poses a clinical dilemma. Diagnosis of VRF in intraoral radiographs, except in cases where the beam is perpendicular to the direction of fracture is difficult. Misdiagnosis often leads to wrong decisions about the design of teeth future treatment plan. The aim of this study was to determine the diagnostic accuracy of reverse contrast enhancement options in digital radiography, and to compare it with the original images to find a suitable method to detect vertical root fracture.
Materials and Methods: In this experimental study, digital radiography with phosphor plate detector was taken from 40 extracted single root teeth. From each intact and fractured tooth, the original and reverse contrast images captured and stored. Two expert observers viewed the images twice with an interval of two weeks. Diagnostic criteria (Accuracy, PPV, NPV, Specificity and Sensitivity) in form of absolute and complete for each observer and each images was calculated. Inter and intra observer reliability was obtained using Mc-Nemar test.
Results: No significant differences in inter-observer reliability between the initial appearance and reverse contrast was observed (P>0.05), but in view of the intra-observer reliability in two cases, the difference was significant (P<0.05). No significant difference in the accuracy, sensitivity, specificity and PPV was observe between the two used images (P>0.05), whereas significant difference between the two images was found in NPV index (P<0.05).
Conclusion: The use of reverse contrast enhancement option for detection of vertical root fracture did not show significant difference from initial view.
Abdolrahim Davari, Soghra Yassaei, Alireza Daneshkazemi, Mohadeseh Khosravanian,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: Orthodontic bracket failure during treatment is a common problem. With the introduction of low shrinkage composites the question is that whether: this sufficient has coefficient bond strength for bonding bracket during orthodontic treatment. The aim of this study was to compare the shear bond strength (SBS) of silorane-based and metacrylate-based composites to metal brackets.
Materials and Methods: 30 human premolar teeth were collected and divided into 2 groups. In group 1, 15 orthodontic brackets were bonded using silorane-based composite, in group 2, 15 orthodontic brackets were bonded using metacrylate-based composite. The shear bond strength of each specimen was determined in an Instron machine. Amount of residual adhesive remaining on each tooth was evaluated using a stereomicroscope. Data were analyzed using T-test to compare the shear bond strength between groups and LSD method to compare the Adhesive Remnant Index (ARI) scores.
Results: There was significant difference in the SBS between the test groups (P<0.001). The mean bond strength of bonding brackets to silorane-based composite was (42.42 ± 7.03) MPa, and the mean bond strength of bonding brackets metacrylate-based composite was (21.08±2.97 ) MPa. No significant difference in the ART was found between groups (P=0.66).
Conclusion: Silorane-based composite provided higher bond strength to orthodontic metal brackets.
Mehdi Araghbidikashani, Elham Esmaili, Gholamreza Eslami, Mohsen Nuori, Hasan Ghaffari, Abbas Salehi,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: The aim of this descriptive longitudinal study was to determine the type of teeth that were more prone in accidental bracket debonding and also to investigate the relationship between broken bracket bond and intervening factors such as age, type of malocclusion and sex.
Materials and Methods: We used a pilot study to determine the correct sample size for this study. According to the pilot study which consisted of 20 records of patients, it was concluded that 576 patient’ records was needed. The mean time for a bracket before it fails was also measured using Kaplan-Meier method. Cox regression analysis was done to examine the effect of age, gender, and class of malocclusion on each tooth with broken bracket. Data were analyzed using the software SPSS 20.
Results: Results showed that the percentage of unexpected broken bracket bond for each tooth varied and they were significantly related only in second premolars in both jaws with malocclusion that was different for each tooth (P=0.037, P=0.004).
Conclusion: Maxillary second premolars and mandibular second premolars had the highest rate of unexpected broken bracket bond in CL II CL I malocclusion respectively. Age, gender and malocclusion had no effect on the unexpected broken bracket bond for other teeth.
Esa Mohamadi Zeidi, Amir Pakpor Pakpour Haji Agha, Asghar Karbord, Banafshe Mohamadi Zeidi,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: Constant contact with dentists, the ability to diagnose early effects of tobacco use on oral health and general health has made the dental clinics to the appropriate place to provide smoking cessation counseling. The aim of this study was to determine the effectiveness of an educational intervention using Trans Theoretical Model (TTM) on the smoking cessation in patients attending dental clinics.
Materials and Methods: This study was a quasi-experimental study conducted in 2013. 40 patients in the experimental and control groups were completed self-administered questionnaire including general and demographic questions, change questionnaire stages, change scale processes, smoking cessation self-efficacy scale, decisional balance scale before and 6 after months educational program. The experimental group received two training sessions through group discussion for 60 minutes. Data were analyzed using Chi-square tests, independent T-test, Mann-Whitney and Wilcoxon tests.
Results: In terms of the patients distribution in the change stages (pre-contemplation, contemplation and preparation), there was no significant difference between the experimental (22.5, 35, 42.5%) and control groups (27.5, 35, 37.5%) before intervention (P = 0.55). However, 10 and 20 percent of patients in the experimental group was reported action and maintenance stage regarding smoking cessation after intervention (P<0.001). Results showed a significant increase in the mean score of experimental process of change, behavioral process of change, proc and self efficacy (P<0.001). Also, the mean score of cons constructs decreased significantly after education in the experimental group (P<0.001).
Conclusion: Results indicated that the educational intervention using the TTM to increase the patients' smoking cessation rate was effective. Therefore, it is recommended that dentists have to become more familiar with TTM frameworks for smoking cessation.
Ezatollah Jalalian, Fatemeh Rajaei, Marzieh Bavaisi, Niloofar Moghaddam, Fereshte Keykha, Rezvaneh Cheraghi,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: Tooth crowning often leads to changes in periodontal index through changes in emergence profile zone. The purpose of this study was to compare the effect of metal-ceramic with that of
All-Ceramic restorations on the plaque a accumulation.
Materials and Methods: In this clinical trial, we used 102 teeth covered with metal-ceramic and all-ceramic restorations. Before and after crowning, plaque index (PI) and gingival indexes (MGl) were measured. Data were analyzed using covariance (ANCOVA) test.
Results: Measured PI and MGI (Mean±SD) in PFM Group prior to crowning were (1.96±0.38) and (1.45±0.48), respectively. In metal-ceramic restorations group, six months after crowning, measured PI and MGI (Mean±SD) were (1.22±0.49) and (1.82±0.61), respectively. Measured PI and MGI (Mean±SD) in All-Ceramic Group prior to crowning were (1.22±0.52) and (1.25±0.29), respectively. In All-Ceramic, six months after crowning, measured PI and MGI (Mean±SD) were (0.88±0.51) and (1.43±0.50), respectively. ANOVA test showed statistical significance difference between metal-ceramic and All-Ceramic Groups in Indexes (P<0.001).
Conclusion: Metal-ceramic and All-Ceramic crowns were associated with inflammatory changes in gingival. Metal-ceramic restorations were associated with higher inflammatory indexes compared with All-Ceramic crowns.
Alireza Daneshkazemi, Abdolrahim Davari, Farnaz Farahat, Neda Pazhoohi,
Volume 28, Issue 2 (7-2015)
Abstract
Background and Aims: The purpose of this study was to compare the effect of chlorhexidine 2%, ethanol 70% and sodium ascorbate 10% and delayed bonding for 1 week on the shear bond strength of composite resin to enamel after bleaching.
Materials and Methods: 90 human central incisors were divided into 6 equal groups: Group 1: no bleaching Group 2: bleaching with carbamide peroxide 45% for 45 minutes Group 3: bleaching + restoring specimens in distilled water for 1 week. In group 4, 5 and 6, after bleaching, 1 cc of chlorhexidine 2%, ethanol 70% and sodium ascorbate 10% were applied for 15 minutes. Composite cylinders were bonded on the buccal surfaces. Specimens were thermocycled for 1000 cycles and the shear bond strength test was done. Specimens were examined under stereomicroscope and SEM. Data were analyzed a sign ANOVA and Bonferroni test.
Results: The shear bond strength values were not significantly lower in the bleached teeth (group 3, 4, 5 and 6) than that of negative control group (group 1) (P=1.000, P=0.069, P=0.081, P=1.000) Bonferroni test results show significant difference between test groups (3, 4, 5 and 6) and group 2 (P<1.000, P=0.007, P=0.008, P<1.000) Under SEM, resin tags in group 2 was thinner and lesser than group 3, 4, 5 and 6. The most adhesive failures were in group 2.
Conclusion: Bleaching with carbamide peroxide and immediate bonding of composite decreased the shear bond strength. Sodium ascorbate 10% and delayed bonding for 1 week were the most effective way.
Allahyar Geramy, Amir Hossein Mirhashemi, Sahar Rafiei Chokami, Ahmadreza Shamshiri,
Volume 28, Issue 3 (10-2015)
Abstract
Background and Aims: Cl II malocclusion is one of the most common abnormalities in human societies and using a simple, affordable and accessible treatment that can be provided by general practitioners or specialists, to prevent future malocclusion complications is vital
. Cl II malocclusion treatment using functional appliances such as twin block and anterior inclined bite plan have less cost, side effects and complications compared to fixed orthodontic or orthosurgery
. Until now, the dentoskeletal changes resulting from the application of twin block and anterior inclined bite plan in patients with Class II malocclusion has not been evaluated. The objective of the present study was to assess the dentoskeletal changes following the use of twin-block functional appliance and inclined anterior bite plan in the patients with class II malocclusion div 1 during mixed dentition.
Materials and Methods: In this retrospective cohort trial, 60 patients with the definitive diagnosis of Class II div. 1 malocclusion having ANB>2 and FMA angel between 20 and 30 and without any previous treatment or syndrome who were treated with twin-block or inclined anterior bite plan appliance were selected and their lateral cephalometries were traced before and after treatment. Selected distance and angular landmarks were measured on the cephalograms with the good reliability (ICC=0.953) and the changes occurred in the landmarks were statistically analyzed using Student t test.
Results: Due to the increased mandibular growth, most of the landmarks experienced significant changes following the treatment with twin-block and inclined bite plan (P<0.05). The appliances corrected Class II malocclusion through improvement of mandibular length and position, maxillary and mandibular skeletal and dental relationships (decreased ANB angle and overjet) and stability of mandibular plan inclination. No significant differences were found between the devices regarding most landmarks changes (P>0.05), however, SNA (P=0.04), overjet (P=0.007) and wits appraisal (P=0.004) changed differently after using the appliances.
Conclusion: Despite with most similarities of both twin-block and anterior inclined bite plan to correct class II div. 1 malocclusion, Due to the advantages of anterior inclined bite plan such as less size, good patient cooperation and simple laboratory preparations the appliance can be used as substitute for complex functional appliances to correct class II div. 1 malocclusion before the growth spurt.
Mehran Bahrami, Maryam Memarian, Farinaz Khodadad Kashi,
Volume 28, Issue 3 (10-2015)
Abstract
Background and Aims: Residual ridge resorption is an unpredictable, unavoidable and time-dependent process which occurs in denture-wearing patients especially those who use mandibular dentures. This process causes more problems in mandible because of its less support, tongue forces and more resorption. Inserting implants in many of these patients requires bone grafts. Overdentures are also more expensive. Denture adhesives are the last option to improve retention and masticatory function in denture-wearers with severe resorption of alveolar ridge. Nowadays only a few denture adhesives are used in Iran and there is not much information about their standard features including, pH, bond strength and washability. The objective of this study was to examine and compare the mentioned characteristics of four denture adhesives (Professional, Corega, Fittydent and Fixodent) and to introduce the most suitable denture adhesive for clinical use.
Materials and Methods: All the methodologies of ISO 10873:2010 were applied. To measure the pH value, 1±0.1g of each denture adhesive was diluted with 5g of propylene glycol and mixed with water. Using pH meter, pH of each group was measured separately for 4 times (n=4) and results were recorded. For the washability test, 4 dentures were fabricated (n=4) and each group of denture adhesives was placed on a denture according to manufacture instructions. For simulating mouth environment specimens were placed in water at 37±2 ̊C bath for 1 hour and then washed with a plastic brush. Specimens were examined for any residual adhesive and the results were recorded. For bond strength test, a sample holder was gently filled with denture adhesives and was attached to the holding arm of bond strength testing device (Santam, STM 20, Iran). Specimens were placed in 300ml water bath at 37±2 ̊C for 10 minutes, and then shaken to be dried and placed in the bond strength testing device. 10N force with 5mm/min rate was applied to the specimen. The force was maintained for 30s and then device arm was pulled back and the highest number was recorded with computer software (Santam Machine Controller v4.19, Iran). The test performed 8 times (n=8) for each adhesive and 8 results were recorded. Data were analyzed using ANOVA test for comparing the bond strength with a significant level fixed
at 0.05.
Results: Professional and Corega adhesives had more neutral pH than that of Fittydent and Fixodent which were more acidic. Washability test showed no remaining mass of any adhesive and there was not any statistically significant difference between groups (P>0.05). Fittydent and Corega adhesives showed higher bond strength than that of Professional and Fixodent and this difference was statistically significant (P<0.05).
Conclusion: Professional and Corega adhesives had less acidity. Thus they cause less harmful effects on the oral mucosa than that of Fittydent and Fixodent and should be indicated in patients with little-tolerant oral mucousa such as diabetous, iron-deficiency anemia and hypertention. All the groups had acceptable washability. Fittydent and Corega had higher bond strength than that of Professional and Fixodent. Therefore in complete-denture-wearers who require more retention as a result of severe ridge resorption, macrotruma, and maladaptiivity, Fittydent and Corega seems to be more acceptable.
