Journal of Mashhad Dental School
Year:2011 | Volume:35 | Issue:2 (77)|Papers Count:12

Introduction: Disinfection of alginate impressions by immersion or spraying method with disinfecting agents is considered for effective infection control. The purpose of this study was evaluation of wear of type III stone casts made from alginate impressions after being disinfected by spray or immersion methods.Materials & Methods: Four common disinfecting agents (5.25% Sodium hypochlorite, 2% Glutaraldehyde, Micro 10 and Deconex) were selected and the samples were divided into four groups of 40 subjects with two subgroups of 20 subjects and a group of 20 subjects were selected as the control group (totally 180 impressions). Each group was disinfected with one of disinfecting agents and each subgroup disinfected by spraying or immersion method for 8 minutes. The control group was not disinfected. After disinfecting, the impressions were poured standardly with type III stone plaster. Using wear machine, surface wear rate was calculated. The data were analyzed using descriptive statistical tests, ANOVA & LSD.Results: The mean surface wearing was statistically different in different groups. Spraying or immersion by Micro 10 and spraying by 5.25% sodium hypochlorite had the least wear and spraying and immersion by Deconex caused the greatest wear. Conclusions: Regarding reduction of surface wearing of casts from disinfected impressions, it is advised to use Micro 10 with spray or immersion methods and 5.25% sodium hypochlorite by spraying.

Introduction: Root resorption is one of the most difficult diagnostic problems in endodontic treatments. Since successful treatment depends on early diagnosis of this pathology, using several diagnostic methods such as radiographic Images based on films, digital images and finally advanced diagnostic techniques are important. Therefore, in this study, we compared digital detector (CMOS) and conventional films by changing the different variables in diagnosis of simulated external root resorption (RR).Materials & Methods: In this in vitro study, in the first group, twelve intact premolar teeth extracted for orthodontic treatments, were selected. On the root surface of each tooth, we created a 2×2 mm window on buccal, lingual or proximal surface in cervical or middle levels and covered the remaining parts of the teeth with nail varnish. The root resorption was stimulated using acid in two different steps. The radiographic images were taken by two detectors, conventional film and CMOS sensor in three angulations (ortho, 15 degree mesial shift and 15 degree distal shift) before and after resorption induction. In the second group, on another 12 premolar teeth, mechanical root resorption was created by bur in two different sizes. The above mentioned steps were repeated the same as the first step. The images were observed by an expert endodontist and radiologist to find out whether there was root resorption or not. The data were analysed by Chi square test.Results: Overall, the rate of correct diagnosis of acidic resorption in digital method (CMOS) was significantly higher than that of conventional method; however, in mechanical resorption the difference was not significant.Conclusion: According to our study, digital radiographs are more effective and helpful than conventional images in diagnosis of external resorption.Variables such as size, shape of cavity, location and level of root resorption are effective in observers’ ability in detection of root resorption.

The aim of this study was surface modification of titanium by a mixed solution of three acids and to see if the roughness created and morphology changes of the titanium surfaces after various exposure times in acid solution could be associated with the biological performance.Materials & Methods: In this experimental study, the surface topography, chemistry and biocompatibility of polished titanium surfaces treated with mixed solution of three acids containing 80%HCl-10%HF and 10%H3PO4 dealing with the acid solution condition time were studied. Fifty-four experimental cases and nine controls were considered. Osteoblast cell line (MG-63) was cultured on titanium surfaces. Also, in order to investigate titanium surfaces, SEM, AFM analyses were carried out. The data were analysed by t-test and One-Way ANOVA.Results: The results revealed that time variation in the aforementioned mixed solution of three acids, had a significant effect on the morphology and surface roughness. In addition, by conducting some changes in immersion time of the mixed solution acid with aforementioned composition, it was derived that time increments up to 120 seconds caused an increase in surface roughness even though in upper periods of time the trend was not regular, as the highest values of R.M.S and Ra were reached after 210 seconds. Biological evaluation results demonstrated that morghology and surface roughness had a significant effect on biocompatibility and osseointegration of titanium.Conclusion: The treatment of titanium by a mixed solution of three acids is an easy and low-cost method for providing the porous titanium surface with bioactive properties for the bone-bonding ability in bio-medical applications.

Introduction: The follicular tissue around impacted third molar has a potential to develop to different lesions. However, it is generally accepted that the absence of abnormal radiolucency indicates the presence of a normal follicle. The aim of this study was to histopathologically evaluate the normal pericoronal radiolucencies associated with impacted third molars.Materials & Methods: The follicular space of 104 third molars with normal follicular space (<2.5mm) in panoramic radiographs was measured. Under local anesthesia, tooth and its follicle were taken out by surgical procedure and after necessary steps, were histopathologically evaluated. Data were analyzed by fisher's exact test, chi-square and logestic regression (a=0.05).Results: Thirty eight cases (36.5%) of all follicles had been collected from male, and 63.5% (66 cases) from female patients.92 follicles (88.5%) had been taken out of mandible and 12 follicles (11.5%) from maxilla. Of the specimens submitted, 41.3% (43 cases) showed cystic changes equivalent to that in dentigerous cysts. Cystic changes in dental follicles were significantly higher in patients over 20 years of age (P<0.0001). No significant difference was detected between sex of patients and cystic changes in follicles (P>0.05). Impacted third molars with normal pericoronal radiolucency more than 1.5 mm showed cystic changes in 63.3% of the cases.Conclusion: This study confirms the idea that the risk of cystic changes increases with age. Considering the high incidence of cystic changes in pericoronal radiolucencies associated with impacted third molars, this study suggests prophylactic removal of impacted third molar.

Introduction: Herbal mouthwashes have been used to improve oral hygiene through antibacterial activity and dental plaque control. The purpose of this in vitro study was to compare the antibacterial effects of Persica and Matrica herbal mouthwashes with Chlorhexidine 0.2% (CHX).Materials & Methods: The disc diffusion method was used to measure inhibition zone of tested mouthwashes on Streptococcus mutans, Streptococcus sanguis, Streptococcus salivarius, Streptococcus sobrinus, Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa and Eikenella corrodens. The paper discs containing mouthwashes were placed on media cultured with bacteria. Blank discs containing distilled water were used as controls. Three samples of each mouthwash were cultured, three times each. In total, including control discs, 240 cultures were performed. After 18 hours of incubation, inhibition zones were measured in millimeter and compared with one another. Data were processed and analyzed using SPSS-16 soft ware and Kruskal-Wallis and Mann-Whitney U-tests.Results: The CHX 0.2% mouthwash significantly exhibited greater inhibition zone than the Persica and Matrica mouthwashes. Persica could not inhibit bacterial growth, except for Klebsiella pneumonia. Also, there were not any significant differences among three samples of mouthwashes and three cultures of each mouthwash.Conclusions: Based on the results of this study, herbal mouthwashes are less potent than the CHX in inhibiting the growth of tested bacteria. Further in vivo/in vitro studies are needed to substantiate present findings.

Introduction: Streptococcus mutans is the most important cariogenic microorganism and plays a major role in the initiation of dental caries. Fluoride mouthrinses can have a significant effect in reduction of this microorganism because of antimicrobial properties of fluoride ion. Two common mouthrinses in markets are Oral-B solution and Irsha solution. The aim of this study was comparison of the efficacy of Oral-B and Irsha fluoride mouthrinses on Streptococcus mutans.Materials & Methods: In this interventional experimental study, 60 girls of a boarding high school were randomly divided into two equal groups of Oral-B and Irsha. They were asked to use mouthrinse for 4 weeks, twice a day. Saliva of each person was collected before and after using mouthrinse and was sent to the laboratory for microbial culture. The data were analyzed by t-test (a=0.05). Results: Both of the mouthrinses significantly decreased the level of Streptococcus mutans in saliva (P<0.001 for Irsha mouthrinse, P<0.001 for Oral-B mouthrinse). Furthermore, it was significantly revealed that Oral-B mouthrinse was approximately twice more effective than Irsha mouthrinse (P=0.00021).Conclusion: Both of Oral-B and Irsha fluoride mouthrinses are effective in decreasing the level of Streptococcus mutans in saliva. Also it was determined that Oral-B mouthrinse was approximately twice more effective than Irsha mouthrinse. Since Irsha mouthrinse has a mild flavour and creates less burning sense, by trying to improve the quality of Irsha mouthrinse, we can practically administer it instead of Oral-B mouthrinse.

Introduction: Microorganisms are the main etiologic factors of periodontal diseases and dental caries. Recently, the use of herbal medications has been considered as an alternative method in elimination of oral microbial agents. Therefore, the aim of this study was to determine the antibacterial effects of Myrtus extract on some common oral bacteria.Materials & Methods: This experimental trial study was performed on nine strains of some oral bacteria. Each strain was cultured in blood agar and Muler-Hintone media. Paper disks 6mm in diameter containing different concentrations of Myrtus extract were placed on the selected media and then inhibition zone (IZ) was measured after 24 hours. Data analysis was carried out using ANOVA and Tukey HSD test.Results: The results of this study showed that, there were no statistically significant differences in IZ between S.Salivarius and S. epidermis in different Myrtus concentrations. The widest IZ was presented in concentration of 2.5% for S.Sanguis, S.Mutans and diphteroid and in concentration of 1% for lactobacillus and in concentration of 1% and 2.5% for S.aureus and finally, in concentration of 2.5% for P.aeruginosa. The narrowest IZ was presented in concentration of 5% for Lactobacillus. The highest sensitivity to Myrtus extract was observed in concentration of 2.5% and the lowest sensitivity in concentrations of 0.5% and 5%.Conclusion: Myrtus extract had different effects in different concentrations and on different bacteria in this study. The widest IZ (16 milimeter) was presented in concentration of 2.5% for P. aeruginosa and the narrowest IZ (6mm) was presented in concentration of 5% for Lactobacillus.

Introduction: It is not possible to avoid the occurrence of emergency accidents in private dental offices. In order to manage the emergency accidents, scientific and practical knowledge is necessary. The present study aimed to assess the presence of both medicine and ancillary equipments in dentists’ emergency kit of private dental offices in four southeast cities in Iran.Materials & Methods: In this descriptive study‚ all dentists working in their private dental offices were invited to help with this survey in four southeast cities in Iran (2007-2008). Data collection method included interview with the dentists‚ observing emergency kit and filling in the checklist by trained experts. Data were analyzed using parametric (t-test) and non-parametric (chi-square & Fisher’s Exact) tests.Results: Among the 126 dentists, 117 dentists accepted to help with the survey (Response rate=92.9%). Mean age of respondents was 36±7.6 years. Mean duration of respondents working in their private offices was 6.6±6.9 years.53% of respondents had participated in emergency medicine courses and only 39.3% had the emergency medical kit in their private offices. Unfortunately‚ all of the kits were incomplete.Conclusion: Mean age of dentists shows that they would work in their private dental offices for a long time. On the other hand, our results showed that a majority of private dental offices in our study did not have emergency kits or existed emergency kits were incomplete. These results confirm the need for planning and managing emergency medicine courses both for dentists and students in dental schools.

Introduction: Malignant lymphoma of the oral region is uncommon and accounts for approximately 3.5% of all oral malignancies. Non-Hodgkin’s lymphoma occurs primarily in adults, although children may also be affected, particularly by the more aggressive intermediate and high-grade forms. The condition most commonly develops in the lymph nodes, but so-called extra nodal lymphoma is also found. In children, extanodal lymphoma is more common. The presentation can be as a non tender mass mostly in cervical, auxiliary, or inguinal regions that has been enlarging for months. In the oral cavity, lymphoma appears usually as extra nodal disease. The malignancy may develop in the oral soft tissues or centrally within the jaws. Soft tissue lesions appear as non-tender, diffuse swelling; they most commonly affect the buccal vestibule, posterior hard palate, or gingiva. The patient may complain of paresthesia, particularly with a mandibular lesion (numb chin syndrome).Case report: An 8-year-old boy was visited in the Oral Medicine Department of Mashhad Dental School with the chief complaint of permanent tooth mobility in the oral cavity for 15 days. The patient also had a history of bone pain mainly in lower lip for the last month and Bell’s palsy (left side) was observed which had been occurred since 7 days before. Simultaneously, the patient had malaise, anorexia, bone pain, illness, lymphadenopathy (head and neck), and flu like signs and symptoms, fatigue and leukocytosis. Under clinical diagnosis of lymphoma, the patient was referred to pediatric hematologist-oncologist. Our diagnosis, none Hodgkin’s lymphoma (NHL), was confirmed by the report of lymph node biopsy. Conclusion: Dentists can play an important role in the early detection of the malignant lymphoma of the oral cavity. NHL primarily appears in the head and neck. It is typically characterized by a swollen, non-painful lymph node although other presentations may pose significant diagnostic problems and frequently lead to misdiagnosis and mistreatment.