مجله دانشکده دندانپزشکی مشهد
سال سی و چهارم شماره 2 (پیاپی 73، تابستان 1389)

The self adhesive composite has been introduced for reducing the process of using composite. The new composites can chemically and micromechanily attach to tooth without using bonding. There are no studies that show the traits of these composites. The purpose of this study was to compare the microleakage of a new self-adhesive flowable composite whit usual bonding (excite), and Tetric Flow composite. In this in vitro experimental Study, 30 freshly extracted caries_free human molars were used. The teeth were randomly divided into four groups of 15 cavities (two cavities in each tooth). Two modified class V cavities (3mm diameter, 2mm depth) were prepared using a round diamond bur [Swiss Tec (806 314)] on the cementoenamel junction of each tooth. The cavities were filled following the order: Group A: Etching/Excite Bonding/Tetric Flow composite, Group B: WetBond composite, Group C: Etching/WetBond composite, Group D: Etching/Excite Bonding/WetBond composite. All samples were then subjected to thermocycling at temperature between 5 and 55°C. 1000 cycles were performed. Next, the specimens were immersed in 2% aqueous solution of basic Fuchsine dye. After that, the teeth were embedded in acrylic resin. Finally, the teeth were sectioned buccolingually in the middle and were evaluated by two independent examiners on a stereomicroscope at 40×magnification to verify the dye penetration. The data were analyzed by Kruskall Wallis (P<0.02) and Mann-Whitney tests (P<0.05). The least microleakage in occlusal region was found in group A and then in group D. The greatest microleakage was in groups B and C. The least microleakage in gingival margin was found in groups D and B and the greatest microleakage in groups A and C. Conclustion: According to this study, use of WetBond Self Adhesive Composite in class V cavities alone is not suggested and using etching and bonding prior to it could reduce the microleakage.

Due to increasing body mass index (BMI) in children, it is necessary to study the effect of the obesity on dental development. If dental development accelerates in obese children, it can affect some orthodontic and pedodontic treatment plans. The purpose of this study was to determine the relationship between dental development and BMI, gender and sex in 7-15 year old children. In this descriptive cross-sectional study, 146 subjects including 89 females and 57 males (29 obese, 35 overweight and 82 normal weight) were studied. Dental age of subjects was determined using the Demirjian method. Weight and height of the subjects was measured and BMI status was determined for each subjects. Chronological age was calculated by subtracting the birth date from the date on which the radiographs were done for every individual. The BMI was used to distinguish the individuals who were overweight and obese. The difference between chronological and dental age was analyzed regarding BMI, age and gender. T-test and 3-way ANOVA were used to data analysis. To determine intraexaminer reliability, 10 panoramic radiographs were reassessed after 2 weeks and dental age was compared using crombach's alpha (0.99). The mean difference between chronologic age and dental age was 0.78 years. Mean difference was 1.3 years for obese, 0.6 years for overweight and 0.67 years for normal weight subjects. Dental development was significantly accelerated in obese subjects (P=0.014). When evaluating the age groups, obese 7-10 year old children showed a statistically significant difference in dental development (P=0.018). There was no statistically significant difference between females and males. Children who were obese had accelerated dental development. In fact when incorporating orthodontic therapies such as growth modification and serial extractions, the timing of intervention may require recalculation to consider body mass index.

Glass ionomer is used in conservative adhesive restoration (CAR) in order to release floride. The purpose of this study was to evaluate the microleakage of glass ionomer and fissure sealant interface in in vitro conservative adhesive restorations (CAR). In this in vitro experimental study, a cavity with diameters of 5 and 3mm and depth of 1 mm was prepared in the buccal surface of 21 human’s intact premolar teeth. The prepared cavities were filled with glass ionomer and cured. Then another groove with diameter of 5mm×0.5mm×0.5mm was prepared adjacent to and in touch with the first box and filled with fissure sealant and cured. In the lingual surface of each tooth, a cavity with diameter of 3mm×3mm and depth of 1 mm was prepared and filled with flowable composite and cured. Another groove with diameter of 3mm×0.5mm was prepared and filled with fissure sealant and cured. Next, the teeth were subjected to thermolcycling (1000 cycle at 5 to 55 ºc and then immersed in a fuschine solution for 24 hours. After that, rate of color penetration between glass-sealant, glass-tooth, sealant-tooth, and composite-tooth was evaluated with stereomicroscope after being buccolingually sectioned. Results were statistically analysed using the Friedman and Wilcoxon tests. The rate of microleakage between glass-tooth was greater than glass-sealant and also the microleakage between glass-sealant was greater than the microleakage between composite-tooth and composite-sealant. The microleakage between composite-sealant was less than the others. According to the results of this study, it is better to use composite instead of glass ionomer in conservative resin restorations.

Stainless steel crowns (SSCs) are widely used in restoring severely damaged primary molar teeth. Since these crowns do not adapt ideally to tooth substance, they may lead to some changes in surrounding gingiva. This clinical study was performed to evaluate the effect of stainless steel crowns placed on primary molars on gingival structures. In this retrospective study, 117 crowns in eighty four 4-11 year old children attended to pediatric department of Zahedan dental school were evaluated. Convenience sampling method was done. Some clinical factors such as gingival index, tooth type, state of being either right or left molar, or upper or lower molar, time elapsed after cementation, crown marginal adaptation, excessive cementation around the margin of crown and the oral hygiene level were examined. Kruskal-Wallis and Mann-Whitney tests were used for data analysis through SPSS 15 software (P<0.05). In our study only 11.1% of the evaluated crowns demonstrated clinically healthy gingiva, and there was a significant correlation between upper and lower molar, crown marginal adaptation and oral hygiene level with gingival index (P<0.05), while gingival index was not significantly affected by tooth type, tooth side, time elapsed after cementation and presence of excessive cement around the margin of crown and sex (P>0.05). Stainless steel crowns had no harmful effect on the gingiva provided performing standard preparation procedures especially in upper molars and stablishing proper marginal adaptation and good oral hygiene level.

Increase in the incidence of contagious diseases emphasizes the importance of microbial contamination of dental materials. The purpose of this in vitro study was to determine microbial contamination of different consumable dental materials for the presence of viable microorganisms. In this study, 19consumable dental materials were surveyed for microbial contamination. These materials included: three kinds of gutta percha, paper cones, gingival retraction cords, alginates, wooden wedges, two kinds of prophylaxis pastes, and one kind of dental dressing and zinc oxide powder. From each material, three brands and from each brand three samples were obtained. Solid and liquid specimens were cultured on Tryptic Soy Broth, Thioglycolate and Sabouraud Dextrose Agar and all of the cultured media were stained by gram method.Data were analyzed by SPSS-16 software using descriptive and analytical (Fisher's exact and Chi-Square) tests. The level of significance was set at 0.05.. Both prophylaxis pastes, one kind of dental dressing and zinc oxide powder, two of alginates, two of wooden wedges and one of retraction cords did not have any bacterial contamination. The most common bacteria in the contaminated materials were anaerobic Gram-positive bacilli (18 cases, 32%), aerobic Gram-positive bacilli (17 cases, 30.4%), aerobic Gram-negative bacilli (14 cases, 25%), aerobic Gram-positive cocci (three cases, 5.4%), anaerobic Gram-negative bacilli (two cases, 3.6%) and anaerobic Gram-positive cocci (two cases, 3.6%). Approximately, 47 percent of tested dental materials did not have any microbial contamination. The bacilli were the most common bacteria in contaminated materials. Although these microbes may not be pathogenic in ordinary conditions, they can represent a risk for immunocompromised patients.

Gloves protect the dental healthcare worker from direct contact with microorganisms in the patient’s mouth and on dental setting surfaces; They also protect the patient from potential pathogens on the hands of the clinicians. This study was performed to evaluate the permeability of three types of examination latex gloves after treatment of patients in pediatric department of Mashhad school of dentistry. A total of 60 pairs of three types of gloves (Supa, Medic-Dent and super Max) and five gloves of each type as control were randomly selected. The effective barrier properties were investigated following one hour treatment including fluoride therapy, amalgam and tooth colored restoration and pulp therapy. The effect of sex and the difference between working and non working hands were assigned too. The permeability of the case and control groups was determined by an electrical test. The voltage of each glove was registered at a current of 0.6 mA, using salt electrolyte solution. The data were analyzed using SPSS statistical software (t-test and ANOVA). comparison of mean voltage of used glove with control in each type showed no significant difference except in Super Max (P=0). Unlike supa and Medic-Dent gloves, greater permeability was detected in super max glove after treatment. The mean voltage of working and non working hand between gloves was not significant (P=0.19). According to this study there was not any difference in permeability of Iranian glove (supa) before and after use.

Generally, a material with less toxicity and greater antimicrobial effect seems more agreeable to use. The aim of this study was in vitro comparison of the antimicrobial effects of Persica® and Chlorhexidine with Sodium hypochlorite on Enterococcus fecalis and Candida albicans. In this in vitro experimental study, 92 samples of study microorganisms were cultured on meuller hinton agar with Kirby bauer method. Paper discs were treated by Persica (pure and 50%), Chlorhexidine (0.1% and 0.2%) and Sodium hypochlorite 1% and placed on the culture media. After 48 hours incubation, Zones of microbial inhibition were measured in millimeters. Data were analyzed by Mann-Whitney and Kruskal-Wallis tests. Sodium hypochlorite was more effective in growth inhibition of the microorganisms than Persica and chlorhexidine significantly (P=0.000). In this study, the microorganisms were very sensitive to Sodium hypochlorite. Reducing the concentration of Chlorhexidine, lessened its effectiveness. There was not any sensitivity to Persica. Totally used concentrations had less effect than Sodium hypochlorite.

It is difficult and sometimes impossible to predict the degree of damage and prognosis of tooth vitality after a carious dental pulp exposure. This predicament is exacerbated by the fact that clinical signs and symptoms do not correlate closely with the histopathological status of the pulp. As clinicians, we are keen to be conservative to maintain pulp vitality; however we must also remove all the infected tissue. Vital pulp therapy (VPT) aims to remove infected dentin, and bacteria, and at the same time to maintain pulp vitality by using a biocompatible material to seal off the pulp and restore the tooth’s strength and function. In the past, calcium hydroxide was used as a biocompatible pulp capping/pulpotomy agent. This has now been generally replaced with either MTA or Calcium Enriched Mixture (CEM) cement. These new biomaterials have good sealability and regenerative abilities, even superior to the traditional material used for VPT; for example, they can induce the production of greater and better quality reparative dentine. CEM cement has been clinically assessed for different VPT treatments such as direct pulp capping and pulpotomy treatments and therefore, its use for different VPT treatments is recommended.

About 1% of all oral cancers are metastases of primary tumors elsewhere in the body and could be located in the soft tissue as well as in the jaw bones. Among all the primary tumors that arise below the level of the clavicle, renal cell carcinoma (RCC) is the third most common neoplasm according to metastasis in the head and neck region. Majority of the reported cases involve the jaw bones rather than the soft tissues. Here one case of metastatic RCC to the maxillary gingival is reported. The Patient was a 75 year-old man who chiefly complained about swelling in his anterior region of the maxillary gingiva. Excisional Biopsy was performed. Metastatic clear cell Renal cell carcinoma (CCRCC) was diagnosed by microscopic examination by demonstrating islands of cells separated from each other by thin fibrovascular septa, with stroma containing numerous sinusoid like vessels and immunohistochemistry (IHC) Staining (S-100, vimentin, EMA, CEA, CD10, CK7,TTF-1 and PSA). CT scan confirmed tumor in the right kidney. Nephrectomy and chemotherapy were performed but patient died 9 months after treatment as a result of metastases to brain and lung. CCRCC arise from renal tubular epithelium. Microscopically differential diagnosis for jaw tumors with clear cells includes a broad spectrum of tumors such as odontogenic tumors, salivary gland tumors and metastatic tumors. Generally, an immunohistochemistry panel consisting of S-100, vimentin, EMA.CEA, CD10.CK7, TTF-1 and PSA is useful to diagnose CCRCC from other clear cell tumors. Although IHC aids us in diagnosis, other paraclinical procedures like imaging should be done, to confirm the diagnosis.