JOURNAL OF ISLAMIC DENTAL ASSOCIATION OF IRAN (MAJALLAH-I-DANDANPIZISHKI)
Year:2006 | Volume:18 | Issue:3 (60)|Papers Count:16

Background and Aim: Various kinds of hand or rotary techniques are used for mechanical preparation of the root canal. The aim of this study was to assess the influence of the number of applications of conventional and two rotary instrumentation techniques (Profile, Flex Master) on the apical extrusion of debris.Materials and Methods: In this study, 73 single rooted mandibular premolars with curvatures between 0 to 10 degrees were divided into three groups. Groups H, P and F were prepared by the hand step-back, Profile and Flex Master techniques, respectively. Preweighed vials (0.0001 precision) containing distilled water was used to collect debris. After canal preparation, the vials were completely dried and weighed again. The weight of the debris extruded from the apical foramen was calculated by assessing the difference between the weights of the vials, before and after canal preparation. One-way ANOVA was used to compare the mean weight differences of the debris between the numbers of applications of the three different techniques.Results: The weight of the debris varied significantly according to the number of times the Profile technique was applied (n=6), i.e. the quantity of debris decreased with increased application. A statistically significant difference was not observed between the numbers of applications using the other studied techniques.Conclusion: New Profile instruments induce more extrusion of debris from the apical foramen as compared to previously used instruments.

Background and Aim: Employing conservative procedures and considering patient comfort are of great importance, especially for dental treatment in paediatric patients. The aim of this study was to compare the efficacy of the Carisolv system with high-speed excavation of caries using rotary instruments, in primary molars.Materials and Methods: Twenty-five children with a mean age of 7.02±1.64 years were included in this clinical trial. Each patient had at least two contralateral primary molars with comparable caries and approximately equal-size access to lesions (N=50). Caries were removed using the Carisolv system and rotary instruments. The efficiency of caries removal was judged on the basis of clinical criteria. Length of working time, need of local anesthesia, and level of patient cooperation were recorded for both methods. Statistical analysis was performed using the MCNemar and paired t-tests.Results: The Carisolv and rotary systems removed 88% and 100% of the caries, respectively (P=0.0001). Working time with the chemo mechanical method was prolonged when compared with the mechanical method (P=0.0001), but it did not negatively affect the childrens' cooperation. 92% of the patients found Carisolv treatment more acceptable than the high-speed excavation system. Furthermore, the chemo mechanical method reduced the need for administration of local anesthesia for cavity preparations (0% versus 28%) (P=0.002).Conclusion: Carisolv is an effective clinical alternative treatment for the removal of caries in primary molars. It is also more conservative of dental tissue and appears to be more comfortable for most patients.

Background and Aim: Alginate is one of the most widely used impression materials in dentistry. Currently, a variety of alginates are available on the market. Quality control should be performed for all dental materials used in Iran. The aim of the present study was to evaluate several parameters of Plastalgin alginate (Made in France) according to the currently valid international standard for dental alginate impression materials.Materials and Methods: The studied parameters were: working time, setting time, compressive strength, permanent deformation and strain in compression. All factors associated with packaging were also evaluated. All tests were performed in accordane with ISO or ADA standards and 6 specimens were employed for each test.Results: The working time of Plastalgin was within standard limits and the mean setting time was found to be 2 minutes and 28 seconds. The strain in compression, permanent deformation and mean compressive strength was 7/35%, 3/25% and 0/74 Mpa, respectively. Our findings did not confirm the information listed on the Plastalgin Ò packages.Conclusion: The investigated parameters were in accordance with ISO standards, except for permanent deformation. Our findings did not correspond with the information written on the packages. Further studies are required to determine the properties of this material.

Background and Aim: Herbal mouth washes are part of the broad spectrum of herbal medicine that is widely used in Iran, especially in recent years. The aim of this experimental study was to evaluate-the antifungal and antibacterial effects of Yarrow, Chamomile and Rhubarb and to compare them with Iranian and foreign 0.2% chlorohexidine mouth washes.Materials and Methods: Microbial samples were purchased from PTCC and herbal extracts were obtained from Gol daroye Isfahan Co. Iranian chlorhexidine was bought from a pharmacy and foreign chlorhexidine (Made in UK) from the Noor center. Bacterial inhibition zone halo was measured and agar dilution was used to evaluate the herbal extracts. The minimum inhibitory concentration (MIC) was determined for all specimens. A validity test was administered for each of the microorganisms and the dilution of the extracts was confirmed in the laboratory. Data were subjected to statistical analysis using repeated-measure ANOVA.Results: The three extracts revealed different antifungal and antimicrobial effects. The highest to lowest antimicrobial effects were seen in Rhubarb, Yarrow and Chamomile, respectively. The antifungal effects were weak in all three tested extracts. A significant difference was observed between the antimicrobial and antifungal effects of the 3 extracts and the 2 chlorhexidine solutions (p<0.01). The antifungal effects of the UK-made chlorhexidine were higher than the Iranian chlorohexidine, and both were higher than the 3 tested extracts. No significant difference in antifungal effects was found between the two studied chlorhexidines.Conclusion: The antibacterial effects of Rhubarb were higher than Yarrow and Chamomile. Further investigation, using more specific laboratory methods along with clinical evaluation is recommended.

Background and Aim: Achieving good moisture control is a common problem encountered in restorative dentistry, especially after applying and curing dentin bonding agents over dentin tissue. The aim of this study was evaluation of the effect of saliva and blood contamination on shear bond strength of cured dentin adhesives.Materials and Methods: Thirty-five extracted sound human molars and premolars were collected and after debridement, stored in 0.5% chloramine solution for one week and preserved in distilled water, afterwards. The buccal and lingual surfaces were ground flat to expose the dentin. These surfaces were etched with 37% phosphoric acid for 15 seconds, rinsed for 20 seconds and dried with a cotton pellet. A single-bottle dentin-bonding agent was applied on the etched surfaces and cured for 20 seconds. This procedure was repeated in order to achieve excellent bonding. The specimens were divided into five groups of 7 each: Group 1 (Control) was not contaminated; in Group 2, bonding surfaces were contaminated with blood and saliva without any other treatment; Group 3 was contaminated and then rinsed and dried completely; Group 4 was contaminated, then rinsed and dried and re-etched for 10 seconds; Group 5 was contaminated, rinsed and completely dried, re-etched for 10 seconds, rinsed, dried, re-bonded and cured for 20 seconds. A composite cylinder built in a plastic mold (2 mm high x 10 mm wide) was .placed on the treated surfaces and cured for 40 seconds. After thermo cycling, the shear bond strengths of all specimens were measured using an Instron testing machine. The data were subjected to one-way ANOVA, with 95% coefficient of confidence.Results: A significant difference was observed between the mean shear bond strength of the contaminated and uncontaminated groups (P=<0.001).Conclusion: Contamination of cured dentin bonding agents with blood and saliva, significantly reduced the shear bond strength of composite to dentin.

Introduction: The increasing use of dental implants has led to a larger number of periimplant problems. Different therapeutic techniques have been suggested to restore the health of soft and hard tissues. The utilization of laser has been recently suggested for the preparation of implant surfaces and eradication of bacteria. Based on different investigations, there is no evidence of applying both guided bone regeneration (GBR) and laser techniques simultaneously for eradication of periimplant lesions.Case Report: Bone loss was encountered on the mesial and distal surfaces of an implant before prosthetic loading in a female patient. Er:YAG laser and GBR by autogenous bone grafting were simultaneously applied for treatment of the defect. The prosthesis was fabricated and loaded after 4 months. The patient then received periodic clinical and radiographic examinations for 18 months. The bone defects on the mesial and distal surfaces resolved completely. There was no evidence of radiographic or clinical symptoms after 18 months.

Background and Aim: One of the main objectives of root canal treatment is to achieve a suitable and 3-dimensional seal in order to prevent tissue fluids and microorganisms from re-entering the root canal system. The aim of this study was to determine the effect of intracanal moisture on the apical seal during root canal obturation using Rosen and AH26 sealers.Materials and Methods: Sixty-four teeth were chosen according to the inclusion criteria: mature apices, straight canals, no intra/extra-resorption or calcification. The root canals were prepared and randomly divided into six groups, after removing the crowns. Two different sealers, AH26 and Rosen, were chosen and the teeth were filled using the lateral condensation technique in three different settings: dry canal, presence of blood and 2/5% hypoclorite in the canals. All specimens were immersed in methyleneblue solution, rinsed thoroughly and dried. The roots were cut longitudinally into two halves. For dye volumetric measurements, all samples were immersed in 65% nitric acid and the volume of the penetrated dye was measured by a spectrophotometer. Two-way ANOVA was used to compare the leakage of the dye in the study groups.Results: The amount of dye leakage was significantly lower in the AH26 groups (P<0/001). There was no significant difference between the three clinical settings in the AH26 and Rosen groups (P=0.857).Conclusion: If the basic obturation principles are carefully administered during root canal filling, intracanal moisture could not affect apical seal, especially when AH26 is employed as a sealer instead of Rosen.

Background and Aim: Various rotary systems are available on the market, therefore selection of a proper instrument for root canal therapy is difficult. The aim of this study was to compare the maintenance of working length and original shape of curved canals and the incidence of procedural errors, using the newly introduced Race and the older Flexmaster rotary systems.Materials and Methods: In this experimental study, 40 resin blocks with a 45° curvature were randomly divided into two groups. After determination of the working length and staining with methylen blue, photographs were obtained. All root canals were prepared using Flexmaster and Race rotary systems according to the manufacturers' instructions. The working lengths were determined once more and the prepared canals were stained with Eosin and photographs were taken. Pre- and post-preparation images were superimposed and changes in the canal walls were evaluated. Data were analyzed using Mann-Whitnney and student t-tests. Results: The mean canal transportation (determined from the inner and outer width measurements) was higher for Race as compared to Flexmaster. The mean loss of working length in the Race (0/54mm) and Flexmaster groups (0/59mm) was similar. The incidence of zips and elbows was %20 and %35 in the Race and Flexmaster groups, respectively.Conclusion: Based on the results of this study, Race instruments produce more changes in the anatomy of severely curved simulated root canals, as compared to Flexmaster instruments.

Background and Aim: Solubility of restorative materials leads to loss of marginal intergrity, surface properties and aesthetics. Thus, the solubility of these materials is of considerable importance. The aim of this in vitro study was to measure the solubility of two types of conventional and resin-modified restorative glass-ionomer cements (Gle).Materials and Methods: Two conventional GlCs (Ionocid F and Fuji II) and two resin-modified GlCs (Iono Gem LC, Fuji II LC) were employed in the present study. A Perspex mould, 7mm in diameter and 2mm thick was used to fabricate five specimens from each material. Samples were suspended in 50 cc distilled water during the study period. To measure solubility, all specimens were dried and weighed at different time intervals, up to one month. Solubility was expressed as the mean weight loss percentage. The results were analyzed using ANOVA with repeated measurements on one factor and Scheffe and t-paired tests (P<0.05).Results: lonocid F and Fuji II LC demonstrated the highest (24.09%±0.87%) and lowest (1.05%±0.74%) solubility values, respectively. The solubility of Iono Gem LC (7.34%±2.20%) and Fuji II (9.01%±1.33%) were intermediate between the other two cements. An increase in solubility was observed during the test period for all studied materials.Conclusion: The solubility of Iranian GlCs was significantly higher than Fuji II and Fuji II LC cements.

Background and Aim: The combination of different processing solutions and dental film types can affect sensitometric properties (density and contrast). The aim of this study was to determine the effect of 4 currently used Iranian processing solutions on the image quality of 2 types of dental films.Materials and Methods: In this experimental-laboratory study, a casted mandibular 2nd premolar along with a step wedge was used to obtain 248 periapical radiographs during 10 working-days. All films were processed in four Irainan processing solutions: Teifsaz, Jahan, Farhan and Champion. Endodontic files were used to assess the diagnostic accuracy. Densitometric evaluation of the lead wedge radiographs was done at the Atomic Energy Organization of Iran using an Iranian digital software densitometry. Data were analyzed using the ANOVA test.Results: The mean density and contrast of the Kodak images was significantly higher than the Agfa images (P=0/001). Films processed with Champion solution revealed the highest radiographic contrast (P=0/001). No significant difference was found between the Agfa and Kodak films in determining the position of the endodontic file (P>0/05). Conclusion: This study showed that the type of processing solution and film can significantly affect radiographic density and contrast. Kodak films processed in Champion solution revealed the highest radiographic density among the studied materials.

Background and Aim: Flowable composite is an appropriate choice for repairing old composite restorations because of its conservative nature, easy application and various colors available on the market. The aim of this study was to evaluate the shear bond strength between old hybrid and new flowable composite resins using Adhes, Single bond, Prompt L-Pop and no dentin bonding agents.Materials and Methods: Eighty acrylic cylinders were fabricated with a standard cavity in the center. Tetric Ceram hybrid composite was placed in the cavities and cured. The cylinders were divided into two groups; one group was kept in water for one month and was then randomly divided into four subgroups. Dentin bonding agents were not used in the first subgroup but the selected bonding agents were applied to the cylinders in the other subgroups. Tetric Flow composite was placed on the primary composite. The same procedure was used for the second group except that the samples were not stored in water for one month. The shear bond strength was measured using a universal testing machine. The data were subjected to LSD variance and independent t-analysis.Results: Shear bond strength values ranged from 33.27 to 16.62 MPa in the first group (in decreasing order: Adhes, Single-bond, control and Prompt L-pop subgroups) and from 32.73 to 18.15 MPa in the second group (in decreasing order: Adhes, Single-bond, Prompt-L-pop and control subgroups). In the first group, a significant difference was observed between the control versus Adhes and control versus Single bond subgroups and also between the Adhes and Prompt and finally between the single bond and Prompt L-pop subgroups. There was no significant difference between the control versus Prompt L-pop and Adhes versus Single-bond subgroups. The results obtained in the 2nd group were similar to the first group.Conclusion: The shear bond strength between aged hybrid and new flowable composite resin may increase after application of dentin bonding agents.

Background and Aim: When using improper recording materials during the fabrication of dentures, the whole process could be compromised in spite of the precision administered during the rest of the procedure. The aim of this study was to compare the flow of Pars Wax, Azardent, Crystal and Asia Wax with the Dental Modelling Wax Detry (Manufactured in Dentsply) according to standard indices of ADA, specification no. 24.Materials and Methods: All flow tests were conducted in accordance with the corresponding ADA specifications. Two samples of each wax (10 mm wide x 6 mm heigh) were prepared. A force of 19.6N (2kg) was applied on each specimen at three different temperatures: 23, 37 and 45°C. The geometric changes were accurately measured with a micrometer and compared to those obtained prior to the tests. The ratios of the dimensions after force application to the initial dimensions were determined. Based on these ratios, wax flows were compared to standard indices. Results: The amount of flow at 23°C and 45°C, obtained for all studied waxes was in accordance with the corresponding standard values, proposed by ADA. However, at 37°C the flow of none of the studied waxes was in the range of the ADA standards.Conclusion: Considering that the tested waxes demonstrated conflicting results at different temperatures when compared with the standard values, further investigation using different batch numbers is suggested.

Background and Aim: Fixed orthodontic appliances usually include brackets, bands and archwires made of Stainless Steel, Nickel-Titanium or Nickel-Coballt alloys that can release metal ions. The aim of this study was to evaluate the presence of metal ions in oral mucosa cells.Materials and Methods: Sixty subjects were included in this study. The study group consisted of 30 orthodontic patients (age range, 18±2 years) with fixed orthodontic appliances in both arches. The control group was composed of 30 subjects with an age range of 20±2 years who were not undergoing orthodontic treatment and had no dental restorations. Mucosa samples were collected by gentle brushing of the internal part of the right and left buccal mucosa of all subjects. Nickel, Chromium and Cobalt cellular content was quantified by atomic absorption spectrometry varian and analyzed using Mann Whitney-U and t-test.Results: Nickel ion concentrations in the control and study groups were 12.26±12.9 ppb and 21.7±11.4ppb, respectively. A statistically significant difference was observed between the two groups (p<0.003). There was no significant difference in the concentration of Chromium ions, between the two groups.Conclusion: Nickel is a strong immunologic sensitizer and chromium and cobalt ions can also cause hypersensivity, dermatitis and asthma. Because of possible adverse biologic effects, scientific research should be directed toward dental materials that not only require mechanic resistance to wear and tear, but also are safe for patients.

Background and Aim: Bacterial contamination of dental materials and devices used in dental clinics and laboratories can lead to infectious diseases in patients, dentists and dental care providers. The aim of this study was to examine bacterial contamination of four dental materials.Materials and Methods: In this analytic-descriptive study, flour of pumice, zinc oxide powder, prophylaxis paste and wooden wedges of available commercial brands were tested. To assure an examiner-blind study, the samples were coded in the microbiology laboratory. In sterile conditions, the samples were inoculated in tryptycase soy broth and sodium tioglycolate for aerobic and anaerobic bacterial growth, respectively. The media was then incubated in 35 degrees centigrade and checked daily.Results: Flour of pumice showed contamination to coagulate-negative staphylococci, enterococcus faecallis, bacillus and diphteroid. Some of the prophylaxis pastes were contaminated with micrococcus roseous, coagulate-negative staphylococci and diphteroid. One brand of wooden wedges demonstrated contamination to staphylococcus, diphteroid and bacilli. Zinc oxide powders were not contaminated. None of the samples showed contamination to anaerobic bacteria.Conclusion: Some of the investigated materials showed bacterial contamination, but the identified bacteria are not pathogen in normal situations.

Background and Aim: Natural mouthwashes demonstrate fewer side effects than synthetic ones, therefore several investigators have studied the possibility of replacing artificial mouth rinses with herbal mouthwashes. The aim of this study was to compare the efficacy of Matrica (a herbal mouthwash) and chlorhexidine (a synthetic mouthwash) in patients with 3-6 mm probing pocket depths (PPD) with chronic periodontitis.Materials and Methods: In a double-blinded clinical trial, 32 patients (10 male and 22 female; age range, 30-50 years), were"selected from those referred to the Faculty of Dentistry, Tehran University of Medical Sciences, according to the inclusion criteria. PPD and papillary bleeding index (PBI) were evaluated for all subjects and phase 1 treatment including scaling and root planning was performed. The patients were divided into 2 equal groups. The study and control groups received Matrica and chlorhexidine, respectively. The parameters were reevaluated after 1 month. Statistical analysis consisted of Mann-Whitney test and Univariant Analysis of Variance.Results: Both mouthwashes improved PPD and PBI. Chlorhexidine was significantly more effective than Matrica in the reduction of PPD (0.94mm and 0.74mm, respectively). On the contrary, Matrigel proved to be significantly more effective on PEI as compared to chlorhexidine (91% versus 79%, respectively). Tooth staining was observed in all Matrica users.Conclusion: With respect to decreasing PPD, chlorhexidine performed better than Matrica; while Matrica was more effective in the elimination of inflammation and PBI. Therefore Matrica is preferred to chlorhexidine during gingivitis treatment.