Vol 7, No 4 (2010)
Proceeding Abstracts
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Introduction: Esthetics and attractiveness of the smile is one of the major demands in contemporary orthodontic treatment. In order to improve a smile design, it is necessary to record "posed smile" as an intentional, non-pressure, static, natural and reproducible smile. The record then should be analyzed to determine its characteristics. In this study, we intended to design and introduce a software to analyze the smile rapidly and precisely in order to produce an attractive smile for the patients.
Materials and Methods: For this purpose, a practical study was performed to design multimedia software "Smile Analysis" which can receive patients' photographs and videographs. After giving records to the software, the operator should mark the points and lines which are displayed on the system's guide and also define the correct scale for each image. Thirty-three variables are measured by the software and displayed on the report page. Reliability of measurements in both image and video was significantly high (α=0.7-1).
Results: In order to evaluate intra- operator and inter-operator reliability, five cases were selected randomly. Statistical analysis showed that calculations performed in smile analysis software were both valid and highly reliable (for both video and photo).
Conclusion: The results obtained from smile analysis could be used in diagnosis, treatment planning and evaluation of the treatment progress.
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Objective: The aim of this study was to evaluate the dimensional stability of casts made from an alginate impression material poured immediately and stored after specific periods.
Materials and Methods: The common alginate used in Iran (Super; Iralgin, Golchai Co., Tehran, Iran) was tested. A master model was mounted on a special device and used to obtain the impressions. These impressions were stored at 23°C (SD=1) and 4°C (SD=1) in 100% relative humidity, then poured with gypsum immediately and again after 12, 25, 45 and 60 minutes. The casts were measured with a traveling microscope with the precision of 0.5 micrometer.
Results: The dimensional stability of the alginate and impressions were both significantly time and temperature dependent. The impressions were dimensionally stable significantly until 12 minutes of storage at room temperature and until 45 minutes of storage at 4°C (SD=1).
Conclusion: The dimensional stability of the alginate impressions was influenced by the storage time and environment temperature, but a humid environment and 4°C (SD=1) temperature may delay the pouring.
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Objective:
By date investigations have indicated the presence of stem cells within the pulp tissue of both temporary and permanent human teeth. In the present study, these stem cells were compared in terms of their growth kinetics and culture requirements.
Materials and Methods:
Stem cells within the pulp of the human third molar (permanent tooth) and the deciduous incisor (temporary tooth) were isolated, culture-expanded and characterized. Then the proliferation potential of the cells was compared using multiple cell growth indices as PDT (Population doubling time), colonogenic activity and growth curve. Furthermore, the cultures of both cells were optimized for maximal proliferation.Results:
Stem cells of either pulp tissue appeared as fibroblastic cells capable of differentiating into osteoblastic, odontoblastic, adipocytic and chondrocytic cell lineages. In contrast to molar stem cells, those from the incisor tooth expressed neurogenic markers of ßIII Tubulin and Tau. Based on in vitro growth data, the cells from third molar tended to have a lower PDT value (20.79, SD=2.8 versus 25.55, SD=2.9 hours), higher colonogenic activity and better growth curve than those from the deciduous incisor (P<0.05). Both cells exhibited high expansion rate when being plated in a medium with 20% phosphate buffer solution at a density of 100 cells/cm2.Conclusion:
Given the high proliferation capacity, the stem cells from the human third molar would be an appropriate candidate for use in experimental, preclinical and even clinical setups. -
Objective: To determine the prevalence and correlated factors of self-reported oral malodor in Thai dental patients from Chulalongkorn Dental Hospital.
Materials and Methods: A self-administered questionnaire was developed to assess the self-reported perception of oral malodor in 839 patients. Significant associations between self-perceived oral malodor and sociodemographics, oral problems and oral hygiene practice variables were determined by Chi-square test.
Results: The prevalence of currently self-perceived oral malodor was 61.1%. A higher prevalence of self-perceived oral malodor was significantly correlated with a number of factors including being 30 years of age or older, having a high school or lower educational level, tongue coating, xerostomia, bleeding when brushing teeth, never receiving professional tooth cleaning and a lower toothbrushing frequency. However, multivariable analysis showed that tongue coating was the factor most strongly associated with self-perceived oral malodor (OR=3.53; CI=2.05-6.08), followed by bleeding when brushing teeth (OR= 2.96) and being 30 years of age or older (OR=2.46). Subjects with oral malodor perceived by themselves and others had a higher level of self-perceived oral malodor, a higher prevalence of bad odor when talking, in the morning and throughout the whole day, and a higher prevalence of consulting with other people in comparison with those with perception by themselves alone.
Conclusion: Tongue coating, bleeding when brushing teeth and being 30 years of age or older were significantly associated with self-perceived oral malodor. The level of selfperceived oral malodor and consulting with other people was more prevalent in subjects with oral malodor perceived by themselves and others.
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Objective: One of the principle purposes of root canal obturation is to obtain hermetic sealing of the root canal system. According to the development of technology, many materials are now used in root canal filling. An in vitro dye leakage study was performed to evaluate the apical sealability of White-colored Mineral Trioxide Aggregate (WMTA) and Gray-colored Portland Cement (GPC) when used alone or as a sealer with gutta-percha points in root canal filling.
Materials and Methods: Seventy-five single-rooted extracted human teeth were used in this study. After cleaning and shaping, the teeth were randomly divided into five equal groups of 15 teeth each based on the root canal filling material used; Group 1, (WMTA) alone; Group 2, (GPC) alone; Group 3, (Gutta-percha points + WMTA); Group 4, (Gutta-percha points + GPC); Group 5, (Gutta-percha points + AH26). Methylene blue was used to determine the apical leakage. After sectioning the teeth longitudinally, linear dye penetration was measured with a caliper under the stereomicroscope. Data were analyzed by Kruskal-Wallis and one-way ANOVA tests with (P ≤ 0.05) as the level of significance.
Results: The results showed that there were no statistically significant differences among the materials of five groups.
Conclusion: (WMTA) alone, (Gutta-percha points + WMTA), (GPC) alone and (Gutta-percha points + GPC) may be used in the root canal filling.
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Objective: Better understanding of the furcation anatomy may serve to decrease the risk of root perforation. The purpose of this study was to measure the thickness of root walls in the danger zone in mandibular first molars.
Materials and Methods: The roots of 53 extracted human mandibular first molars were sectioned in the horizontal plane 4 mm below the orifice of the mesial and distal root canals. For each cut surface buccal, lingual, mesial, and distal thickness of the root wall was measured. Mean values of the thickness at each location were calculated and compared by ANOVA and t-test.
Results: The results showed that the mean thickness in the distal portion of the mesial root was smaller in comparison to all other portions of the roots (P<0.05) and this difference was statistically significant except for the mesial portion of the distal root (P=0.463). The mean thickness of radicular dentin at the distal aspect of mesial roots was 1.2 millimeter.
Conclusion: Our study suggests that knowledge of the root dentin thickness in the danger zone is essential for preventing endodontic mishaps leading to failure.
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Objective: In this study, the effect of bur cutting efficacy was evaluated on microleakage
of class V composite restorations with two adhesive systems.
Materials and Methods: Class V cavities were produced on sound extracted human teeth,
which had been assigned randomly to one of six groups (N=15) as follows: Groups 1 and
6 were prepared using used rough diamond bur; Group 2 and 5 were prepared using new
rough diamond bur; Group 3 and 4 were prepared using soft diamond bur. After application
of Single Bond (3M Dental Product, USA) in groups 4,5 and 6 and Clearfil SE Bond [
Kurary Medical Inc. Japan] in groups 1,2 and 3, all cavities were restored with composite
resin. The teeth were thermocycled and microleakage was evaluated by dye penetration.
Kruskal-Wallis and Mann-Whitney tests with Bonferroni's correction were used for statistical
analysis.
Results: The results showed that gingival margins significantly leaked more than occlusal
margins for all bur types and bonding systems. Using the same adhesive system in gingival
margins, significant difference was seen between bur types and using the same bur
type in occlusal margins, there was a significant difference between the two types of adhesive
systems.
Conclusion: Cutting efficiency of bur had a great effect on microleakage of resin composite
restorations. So long term use of burs may result in an increase in microleakage of
composite resin restorations. -
Lipomas are rare benign soft tissue mesenchymal neoplasms in the oral cavity,
representing 1% of all benign oral tumors. Fibrolipoma (FL), an uncommon, histological
variant of the classic lipoma, mostly affects the buccal mucosa. Very few cases of FL have
been reported in the English literature. To the best of our knowledge a review of the English
literature showed 33 cases of FL affecting the oral cavity.
The diagnosis and differentiation of FL with clinically similar lesions such as fibroma,
mucocele and pleomorphic adenoma are very essential for a correct treatment plan and
complete follow-up. Due to the rarity of oral cavity fibrolipoma reports, three cases and a
review of literature is presented here.
