Caspian Journal of Dental Research

Introduction: The degree of polymerization depends on the type of light-curing unit. The aim of this study was to compare the hardness of composite resin cured by LED and Halogen light curing units.

Methods: In this experimental study, 20 cylindrical samples of Tetric Ceram composite were prepared. Half of them were cured with Ultralume 2 LED and the other half with Astralis 7 Halogen light curing unit. In the depths of 0,1,2 and 3 mm from surface, one point in peripheral and one point in central portion were marked ,then the hardness of these points was measured by Vickers test . The data was analyzed by a pvalue less than 0.05 considered as significant.

Results: The mean hardness of samples cured by LED was more than halogen group in different depths and this difference was statistically significant in peripheral points (p=.048) but this was not significant in central points (p=0.644). The mean hardness in both groups had a decreasing trend from surface to the deep parts in central and peripheral parts and this was more in the central parts.

Conclusions: Composites cured by LED light curing unit showed more hardness in similar depths, besides the hardness of composites in central parts is more than the peripheral ones in both groups.

Introduction : Previous researches showed that neutral soaps significantly increased bond strength and decreased microleakage of dentin bonding agents. The aim of this study was histopathological evaluation of the effect of sodium sulfonate application as neutral soap on the cat's dental pulp after an ideal composite restorative treatment . 

Methods: Ten adult cats with 40 caries-free canine teeth were selected for the study. Class V cavities were prepared in the buccal surfaces of all the teeth. The teeth of the right quadrants were treated with composite, whereas the teeth of the left quadrants were primarily etched, after using of sodium sulfonate solution, they treated with composite. The first five cats were killed after one week and the other five cats after one month. The teeth were fixed, decalcified and after being sliced, paraffined blocks were made and microscopic slides were prepared and histologically evaluated.

Results: The results of the histological evaluation showed that there were no statistically significant differences between the intensity of inflammation in the pulp of the teeth in the right and left quadrants after one week (P=1.000) and one month (P=0.773). However, there was significant difference after one week regarding predentin formation (P=0.017) and in the teeth of the left quadrants, the formation of predentin was more that the right quadrants, but no meaningful difference was observed after one month (P=0.203).  

Conclusion: It seems that the sodium sulfonate in composite restorative treatments without fear of damage to the pulp can be used.

Introduction: The antioxidant properties of chocolate and other flavored additives besides the sugar added to milk raises the question about the acidogenecity of flavored milk. This study was conducted to measure the pH changes of dental plaque and saliva after the consumption of flavored milk and evaluate the antioxidant property of them.

Methods: This study was performed on 42 samples of dental plaque and 42 samples of saliva in 6-11 year old school going children. Milk with flavors of strawberry, chocolate, banana, honey and slim milk were evaluated, all from the same manufacturer with a similar production date. At the beginning of the study on the first day, children were given thorough oral propHylaxis and they were instructed to avoid any method of oral hygiene for 48 hours to permit enough plaque deposition. On the third day the children were divided into 7 groups, 6 children in each group. The supra-gingival plaque was collected through the help of an excavator #3 which was pulled twice with the same force on the tooth surface. The saliva was collected using spitting technique. Each child swished 10 cc of milk for 1 minute in his/her mouth. Fresh plaque samples after 5, 10, 20 and 30 minutes and saliva samples immediately, after 5, 10, 20 and 30 minutes were collected. The pH of the samples were recorded by a pH testing apparatus (Basic 20+, Crisom). To evaluate the antioxidant property of studied milk, Frap test was performed. The collected readings were reported as mean±SD and analyzed by ANOVA repeated measures, Post hoc Tukey and Paired T-test. In this study, p≤0.05 was considered as significant.

Results: After 30 minutes, honey milk caused the least drop 0.74±0.30 and banana milk caused the highest drop 1.38 0.25 in plaque pH (p≤0.05). After 30 minutes, the pH of saliva showed no significant difference compared to the initial pH. Chocolate milk contained the highest (1000 micromol/liter) and banana milk the lowest (706.25 micromol/liter) antioxidant concentration.

Conclusions: Because of the highest antioxidant properties and reduction of dental plaque PH to a lesser extent, milk with honey, chocolate and coffee is more recommended for children.

Introduction: Apical seal in blood or dry root canal is a problem in endodontic treatment. Failure of apical seal causes inflammatory reaction and failure root canal treatment. Because of the sealer properties, root canal should be dry for obturation. But hydrophilic sealers can adhere to root canal walls nowadays and this problem is still controversial. This study aimed at determining the apical microleakage of AH26 and MTA Fillapex sealers in dry and bloody condition.

Methods: This experimental in vitro study was done on 48 extracted central teeth. The researchers used the Mtwo rotary files for root canal instrumentation. In this process, the teeth were divided into four groups (2 dry groups and 2 bloody groups) and two groups as positive and negative control (each group of 4 teeth). All sealers were prepared according to the factory instruction and the obturation was done with gutta-percha and sealer. After 7 days in 100% moisture condition, the teeth were placed in the ink for 3 days and then were cut across longitudinal axis and the level of microleakage was measured by stereomicroscope.Finally, the data were analyzed by SPSS software, ANOVA, Chi-Square and t-test statistical tests.

Results:The mean of MTA Fillapex and AH26 apical microleakage in blood groups were (448.61± 34.67) Mm and (429.84± 31.63) Mm respectively. The minimum microleakage belonged to AH26 sealer, but it was not significant.

Conclusion: AH26 sealer is a better barrier against microleakage in comparison with MTA Fillapx, although it is not significant. Also, the evidence suggests drying the canal leads to a better apical seal and the blood significantly increases apical microleakage. 

Introduction: Radiopacity is a necessary property for luting cements . The aim of this study was to investigate the radiopacity of some luting dental cements used in prosthetic dentistry.

Methods: Five disclike samples of each material (6 x 1 mm) were prepared from panavia F2.0(Pa), Chioce2 (Ch.2), Glass ionomer GC (GI GC), zinc phosphate Hoffmann’s (ZP hof), zinc polycarboxylate Hoffmann’s (ZPC hof), Glass ionomer ariadent( GI ari), zinc phosphate ariadent(ZP ari) and zinc polycarboxylate ariadent (ZPC ari). The radiopacity of each material along with aluminium step wedge were measured from radiographic images using a digital radiography. The average measured radiopacities from five areas were taken into account, which were measured by Digora for windows (DFW) software using a PSP digital sensor.

Results: There was a significant difference between radiopacity value of all luting materials (P≤0.001). ZP ari had the highest radiopacity with 7.7±0.55 mm aluminium. The Glass ionomer ariadent ari dent showed the lowest radiopacity value with 0.82±0.31 mm aluminium.

Conclusion: All dental cements showed radiopacity values equivalent to or greater than the ISO 4049:2000(E)standard except ariadent Glass ionomer and this could be considered suitable for use in restoration cementation.

Introduction : Periodontitis and dental caries may be synergistically associated, negatively associated, or completely independent.The aim of this study was to evaluate the correlation between these two diseases and investigate the prevalence of dental caries in periodontitis.

Methods: This cross- sectional study has been performed in 180 samples in two groups: periodontal and control group during 2012-2013 in Babol Dental School.All 180 patients were divided into two groups, including 90 cases with chronic periodontitis as the periodontal group (PG) and 90 cases with healthy gums as the control group ( probing depth between 2- 3 mm) (HG).Clinical measurments including Gingival Index ( GI), Bleeding Index( BI), Clinical Attachment Loss (CAL), Periodontal Pocket Depth (PPD) were used to assess the severity of periodontal disease . The clinical features of control group were healthy gums , probing less than 3 mm in depth, and CAL< 1mm . The examination to measure AL was conducted using a Williams’s periodontal probe .In chronic periodontitis group , the patients had GI≥1 and CAL ≥ 1 .The assessment of caries of patients was conducted using bitewing radiography for proximal caries detection , dent on the use of explorer and direct observation. A p-value≤0.05 is considered as significant.

Results: The results of this study showed that the mean number of decayed and filled teeth (DFT) in periodontal group was 4.32 ± 0.17, and in healthy group was 2.16 ± 0.17.DFT in males with periodontitis was 4.85 ± 0.17 and in females was 4.3 ± 0.17 ,while the healthy males was 2.54 ± 0.17, and females was 2.25 ± 0.17 therefore, the mean DFT in the periodontal group was more than the healthy group (p≤0.05) .

Conclusion : Based on our findings, in patients with periodontitis, more dental carries were more significant than the healthy group.

Introduction:Discoloration of the resin-based composites is a common problem in restorative dentistry. There are many factors associated with the discoloration of dental materials in the oral environment. The purpose of this study was to evaluate the color changes in a nano-composite cured with a quartz-tungsten-halogen (QTH) and light emitting diode (LED) unit.

Methods:80 disk-shaped specimens were prepared using Filtek Z350 XT.The specimens were cured with two LED units (Valo and BluephaseC5) and QTH ) Astralis7 ( with two different energy density (400 & 750 mW/Cm²). The color of the materials was measured before and after immersing in tea and artificial saliva. Color change value (ΔE) were calculated and analyzed by 2-way ANOVA and Tukey’s test.

Results: In artificial saliva group, the composites cured with Astralis7 and BluephaseC5 showed significantly more color stability. In tea group, the composites cured with BluephaseC5 significantly had the least color change.

Conclusions: The type of light curing unit does not affect the color stability. Exposure time and interaction between light source and photo initiator content in composite may be the most important factors affecting color stability.

Introduction: Simultaneous etching of enamel and dentin using the novel generation of adhesive systems with contracted operational steps, has shown a good clinical efficacy. The aim of this study was to evaluate the microleakage of composite restorations using the V and VII generations of adhesive systems on primary teeth.

Methods: This study was performed on 45 human intact extracted primary teeth. Following class V cavity preparation, the samples were randomly divided into three groups included 15 teeth based on the type of bonding agent Single Bond 2, Clearfil S3 Bond or G Bond. After applying the bonding agents, the teeth filled with composite Z250. The microleakage values of incisal and gingival margins were separately scored by 2% basic fuchsine staining based on a 0-3 ordinal ranking system. The data were analyzed by using Kruskal Wallis and Mann_whitney U tests.

Results: In overall, the score of microleakage at incisal (0.58±0.94) and gingival (1.06±0.19) edges did not have significant difference. Also, there was no significant difference between incisal and gingival microleakage considering the different types of bonding.

Conclusion: Regarding to less operational steps and lower risk of salivary contamination, the VII generation of dentin bonding agents can be applied for filling the class V cavities of primary teeth.

Introduction: Since crown lengthening surgery could be accompanied by stress, pain and discomfort, knowledge about its predisposing factors could reduce the demands for such surgery.The aim of this study was to identify the most important indications of crown lengthening surgery in order to present new ideas to clinicians on how to reduce the need for this surgery.

Methods: This cross-sectional study was done on 470 patients (aged 12-89 years) referred for crown lengthening surgery. The patients' demographic data and their reasons for surgery, the teeth restoration condition and its type, condition of the opposite tooth, type of fractured cusp (posterior teeth), root canal therapy condition and quality, and size of existing intracanal posts were recorded in a data sheet. Data were analyzed by using SPSS software.The chi-square and fisher exact test were used for statistical analysis. The significant difference was p<0.05.

Results: The most frequent indication in men and women was dental caries followed by tooth fracture.The second upper premolars and first lower molars needed crown lengthening surgery more often, respectively.

Conclusions: Since dental caries and fracture are the most important factors that predispose teeth to crown lengthening surgery, controlling caries with a regular recall sequence can reduce the need for such surgery, especially in the elderly.

Introduction: Sealing pits and fissures was introduced as an approach to prevent occlusal caries for more than two decades. The aim of this study was to compare the microleakage of flow able resin reinforced glass ionomer (Ionoseal) with other materials used as fissure sealants.

Methods: In this in vitro study, 50 premolar teeth of human free of any caries were selected. Fissurotomy was done with fissure bur. The samples were randomly categorized into five groups (Fissurit FX, Fuji II light-cured,Grandio flow, Ionoseal). Ionoseal was assessed by using two methods: with and without etching and bonding agent prior to sealant application. After sealant placement, all surfaces of the teeth except 2 mm area around the sealant margins were covered with two layers of nail polish.The specimens were thermocycled, and they were sectioned after immersing into a 0.5 % basic fuchsine solution. The amount of microleakage was examined by stereomicroscope.

Results: The microleakage comparisons of groups indicated that Ionoseal without etching and bonding application had significantly greater microleakage than the other groups (p<0.001), while there was statistically no significant difference between the microleakage of Ionoseal and the other groups after etching and bonding application (p>0.05).

Conclusions: By considering isolation difficulties in children and observing high amount of Ionoseal microleakage (without etching and bonding application), the samples need to be etched and bonded like other resin-based materials before Ionoseal placement in order to achieve clinically desirable microleakage outcomes.

Introduction: One of the main disadvantages of composites is marginal microleakage using flowable composites as a liner beneath composite restorations has been recommended to reduce microleakage. The aim of this study was to assess the microleakage of class II restorations with different flowable composites liners.

Materials & Methods :45 extracted premolars teeth with class II cavity preparation (90 cavities) were divided into five groups and filled as follows: 1.control group: hybrid composite(Z250) 2. Z250+surefil SDR flow 3.Z250+filtek supreme xt flow composite 4.Z250+Grandio flow 5.Z250+Tetric flow. Mesial and distal cavities were filled using snowplow and layering technique, respectively. After that, the samples were immersed in 0. 5% fuchsin solution and sectioned. Gingival microleakage was then graded. Data were analyzed using Kruskal Wallis and Mann Whitney U test.

Results: There was no significant difference between the snowplow and layering methods. Microleakage of Tetric flow and Grandio flow liners was significantly higher than the control group. Other flowable composites showed no significant difference in comparison with the control group.

Conclusion: In the present study, the results indicated that the flowable composites were not effective on reducing gingival microleakage.

Introduction: One factor affecting the degree of polymerization is the type of light-curing device. The aim of this study was to compare the effects of LED and QTH light curing units on the surface hardness of composite and compomer.

Materials & Methods: In this experimental study, 30 samples of composite and compomer were divided into 3 groups of 10 each. One-half of the subgroups in each group were cured with LED and the other half with Halogen light curing units (LCUs). 49 points on the surface were marked and then the hardness of these points was measured by using Vickers hardness test.

Results : The mean hardness of composites cured by using LED was more than the Halogen group but in compomer it was reversed and this difference was statistically significant (p<0.001). Z 250 composite had the highest level of hardness and the lowest hardness was related to the Heliomolar composite and had significant difference. (p<0.001)

 Conclusion :In the present study, the results indicated that LED light curing unit had great effect on the hardness of composites but in compomer, the QTH showed a better result.

Introduction: As the absorption of radiation in environment is increasing, the present study was performed to evaluate the knowledge and practices of Babol’s dentists about x-ray protection .

Materials &Methods: This cross-sectional study was designed to assess the knowledge and practices of dentists. The questionnaires were distributed among 70 dentists in Babol city. Analysis of the collected data was done using the Pearson correlation coefficient in SPSS software version 19 (α=0.05).

Results: In this study, 70% and 30% of studied dentists had good and moderate knowledge, respectively. 96% of them were moderate in terms of practice and 70% of them had good awareness towards the use of a lead apron and thyroid collar but 78.6% and 75.7% of offices had no lead apron and thyroid collar. There was a significant relationship between experience and awareness (p=0.003).

Conclusion: According to the results, their appropriate knowledge and practice were poor. Therefore, it is necessary to control the dental radiographic centers.

Ameloblastic fibroma is a relatively rare benign odontogenic tumor with two neoplastic components both epithelial and ectomesenchymal. A 10-year-old girl was referred to a dentist for routine dental treatments for evaluation of the distance between mandibular right first permanent molar and mandibular right second deciduous molar and it was associated with an undesirable backward movement of erupted mandibular right first permanent molar and forward movement of mandibular right second deciduous molar. The lesion was enucleated and the material was sent for histopathologic examination. Microscopically, it was composed of neoplastic proliferation of odontogenic epithelium consisted of cords and islands in a cell-rich mesenchymal stroma, with histopathological diagnosis of ameloblastic fibroma. After 24 months of follow-up, no recurrence was observed and the mandibular right first molar was spontaneously aligned. Early diagnosis and proper management will prevent comprehensive orthodontic treatment.

Introduction: The aim of this study was to investigate the effect of dentinal pretreatment on the static contact angle of a bonding agent as a measure of dentin surface wettability.

Materials &Methods: Twenty mid-coronal dentin surfaces were prepared and randomly allocated to four groups (n=5) according to the priming solutions. All segments were etched with 35% phosphoric acid gel for 15 s, rinsed for 30 s and dried. Each group was rehydrated with 10 µL of distilled water, 0.2 % chlorhexidine, 70% ethanol and 5.25% Sodium Hypochlorite respectively and the excess solution was removed after 60 sec using an absorbent paper. Using a micro syringe, a droplet of the Adper Single Bond 2 was placed on each prepared surface. Then the profile and the static contact angle of the droplet were analyzed with a video-based optical contact angle measuring system. The statistical analysis was performed using One-way ANOVA and Dunnett’s t tests (p<0.05).

Results: There was a statistically significant difference between the water and sodium hypochlorite groups which indicates the negative effect sodium hypochlorite may have on dentinal surface energy. (p=0.013). The differences between the water and ethanol groups (p=0.168) and between the water and chlorhexidine groups (p=0.665) were not significant.

Conclusion: The use of 5.25% sodium hypochlorite as a priming solution in bonding procedure is not recommended. There is no improvement in dentinal surface wettability by using 70% ethanol or 0.2% chlorhexidine instead of water and the recommendation for use of any of the two should be based on other long-term or short-term effects they may have on the bonding procedure.

Introduction: Internal bleaching is a treatment option for wightening endodontically treated discolored teeth. Cervical resorption is one of the side effects of this method.The aim of this study was to compare the sealing ability of resin composite and light-cured resin modified glass ionomer (RMGI) as intra-orifice barriers in internal bleaching.

Materials &Methods: In this study, 34 single-canal anterior teeth were used. All samples were endodontically prepared and divided into two experimental groups (n=12) and two control groups (n=5). In the experimental groups, Gutta-percha was removed up to 3 mm below the cemento enamel junction (CEJ). RMGI and composite resin was placed over gutta-percha in the experimental groups up to the level of CEJ. After 24-hours incubation period, the bleaching agent (a mixture of sodium perborate and 30% hydrogen peroxide) was placed in the access cavities. The bleaching agents were replaced every 3 days over 9 days. Then, the access cavity was filled with 2% methylene blue for 48 hours. All samples were longitudinally sectioned and the dye penetration range was evaluated using stereomicroscope. Data was statistically analyzed by using T-student test and variance analysis.

Results: The microleakage in RMGI group was 0.945mm and in composite resin group was 0.641mm. Statistically, no significant difference was observed in microleakage between the experimental groups (p=0.121).

Conclusion: Both materials can be applied as the intra-orifice barriers for internal bleaching.

Introduction: Bleaching of discolored tooth may affect the tooth/composite interface. The aim of this study was to evaluate the effect of different concentrations of carbamide peroxide (CP) on the marginal seal of composite restorations bonded with a self-etch adhesive.

Materials and Methods: In this experimental study  Class V cavities were prepared on the buccal and lingual surfaces of 24 intact extracted human molar teeth with gingival margins in dentin and occlusal margins in enamel. The cavities were  restored  using the adhesive system Clearfil SE Bond and the composite Filtek Z250. Finally, they were randomly divided into four groups (1 control and 3 bleached groups). The control group was kept for two weeks in distilled water at 37° C. The bleached groups were bleached with 10%, 22% and 35% CP gel for 8 hours a day for 14 days. After that, the samples were immersed in 0.5% fuchsin solution and sectioned. Then gingival microleakage was graded. Data was analyzed using Kruskal Wallis and Mann Whitney U test (Pvalue≤0.05).

Results: Microleakage was observed  in the gingival wall of all groups. There was a significant difference between the control group and the bleached groups. Microleakage in the 22% bleached group was less than the other concentrations, but this difference was not significant.

Conclusion: Bleaching with different concentrations of CP  can increase the microleakage of the gingival wall of Composite restorations bonded with clearfil SE Bond self-etch adhesive and does not recommend.

Introduction: Since the emergence of normal occlusion concept, selecting an appropriate treatment plan with or without tooth extraction has been a controversial subject. Nowadays, both methods can be successfully used for treatment of patients. However, some clinicians still believe that non-extraction orthodontic treatments have fewer complications. The purpose of this study was to evaluate dental arch dimensional changes following non-extraction orthodontic treatment.

Materials &Methods: A total of 200 pre- and post-treatment diagnostic dental casts belonging to 100 patients (non-ext treated by 0.18 roth system) who met the inclusion criteria for this study were collected from the archives of Shahid Beheshti Dental School. Sampling was nonrandomized. A digital caliper with the accuracy of 0.1 mm was used for the measurement of variables such as inter-canine width , inter-premolar width and inter-molar width.

Results: Non-extraction orthodontic treatment increased all the variables, except for the mandibular inter-canine width and incisor-canine distance.

Conclusion: Non-extraction orthodontic treatment causes a significant increase in almost all dental arch parameters. This increase manifests as teeth flaring.

Introduction: Evaluation is a critical issue to achieve the goals of academic education. The aim of this study was to evaluate the achievement level of educational objectives in Babol dental school using the CIPP (content, input, process, and product) model based on the point of view of students.

Materials &Methods: This cross-sectional study was performed using a researcher made questionnaire based on CIPP model for three educational groups of pediatrics, orthodontics and restorative dentistry among dental students accepted in 2008 and 2009. Total scores were calculated for each field and categorized as undesirable, relatively desirable and desirable with scores below 50, 51-70 and 71-100, respectively. Statistical analysis was performed using ANONA, T-test and Tukey HSD tests and p<0.05 was considered significant.

Results: The mean scores were desirable in all groups. Mean scores allocated to the content, input, process and product areas were not significantly different in the pediatrics, orthodontics and restorative dentistry groups.

Conclusion: Based on the student’s point of view, the pediatrics, orthodontics and restorative dentistry departments of Babol dental school were  successful in achieving educational goals.