Vol 4, No 4 (2007)
Proceeding Abstracts
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Objective:
Considering the fact that several bonding agents are available in market, clinical evaluations are required to find the durability of the sealants after using bonding agents. The purpose of this study was to compare the durability of the fissure sealant after applying two kinds of dentin bonding materials, AdheSE and Excite.
Materials and Methods:
In this clinical study sample group consisted of hundred permanent first molars teeth of forty two children. Convenience sampling method has been applied. After three, six and twelve month follow-up, marginal integrity, retention rate and caries in experimental groups were examined. Data were analyzed according to Fisher's Exact, Chi-Square and Mann-Whitney statistical tests.
Results:
There was no statistical significant difference between the two examined groups,considering marginal integrity, retention rate and caries. In AdheSE group, maxillary teeth had a better retention than mandibular ones.
Conclusion:
It seems that in pediatric dentistry use of Excite as a bonding agent before the placement of fissure sealant is preferable.
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Objective: Bioactive glass is often used as a filler material for repair of dental bone defects.
In different studies osteogenic potential of this material was proved, but its dentinogenesis
property is in doubt. The purpose of this study was to evaluate the histological
pulp responses of Calcium hydroxide and Bioactive glass placed directly on exposed pulp
tissues.
Materials and Methods: Twenty teeth to be extracted due to orthodontic reasons were
selected. These teeth were divided into two groups and treated with direct pulp capping.
Calcium hydroxide was used for 10 teeth and Bioactive glass for 10 teeth. After 60 days
the teeth were extracted and prepared for histological evaluation. Finally the data was analyzed
with exact Fisher test.
Results: All teeth treated with Calcium hydroxide showed inflammation. Internal resorption
was seen in six teeth, abscess in five teeth and dentinal bridge in two teeth. Inflammation
was seen in three Bioactive glass samples and dentinal bridge in seven teeth, but internal
resorption and abscess were not seen.
Conclusion: Bioactive glass appears to be superior to Calcium hydroxide as a pulp capping
agent in primary teeth.
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Objective: The aim of this study was to evaluate and compare the status of supporting tissue around implant-supported fixed partial denture with or without cantilever clinically and radiographically during a four-year period.
Materials and Methods: One hundred and fifty nine patients who were treated by 482 implants supported fixed partial prosthesis with and without cantilever after at least four years of treatment, were evaluated. Clinical and radiographic indices of plaque index, probing pocket depth, bleeding index, and marginal bone loss were measured. Collected data were analyzed by Mann-Whitney, Fridman and repeated-measures ANOVA tests using SPSS software.
Results: The overall survival rate of implant supported prosthesis was 95.9% after at least four years of treatment. The success rates of implant supported fixed prosthesis with and without cantilever were 94.6% and 96.8% respectively. Marginal bone loss in the cantileveredfixed prosthesis was significantly more than the second group after two and four years of treatment (P<0.001), however, all the clinical indices were not significantly different.
Conclusion: Considering the guidelines of cantilever prosthesis applications, using the cantilevered fixed partial dentures have a similar and comparable prognosis as the traditional implant-supported fixed prostheses.
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Objective:
Adverse surface interactions between one-bottle adhesives and chemical-cured composites may occur with delayed light activation of light-cured composites. The purpose of this study was to assess the Effects of delayed activation of light-cured composites on shear bond strength of two one-bottle adhesives with different acidity to bovine dentin.
Materials and Methods:
Flat dentin surface was prepared on sixty-six bovine incisors using 600 grit carbide papers. Prime&Bond NT, and One-Step adhesives and resin composite were applied in six groups: 1) immediate curing of the composite, 2) the composite was left 2.5 minutes over the cured adhesive before light activation, 3) prior to delayed activation of the composite, the cured adhesive was covered with a layer of nonacidic hydrophobic porcelain bonding resin (Choice 2) and cured immediately. After thermocycling, shear bond strength (SBS) test was performed using a universal testing machine at 1 mm/min crosshead speed. Data were analyzed with Friedmans two-way Non-parametric ANOVA.Results:
The SBS of delayed activation of Prime&Bond was significantly lower than immediate activated (P<0.05). Decrease in the SBS of One-Step was not statistically significant after delayed activation. The SBS of delayed activation of Prime&Bond and One- Step with an additional resin layer was significantly higher than delayed activation (P<0.001).Conclusion:
The bond strength of Prime&Bond might be compromised by the higher acidity of this adhesive during the 2.5 minutes delayed activation of light-cured composite. Addition of a layer of hydrophobic resin compensated the effect of delayed activation and improved the bond strength. -
Objective:
The aim of present study was to evaluate the quality, density and thickness of newly formed bone in experimental defects treated with Combi-Pack®, Bio-Oss® and Biostite®.
Materials and Methods:
Eight New Zealand white rabbits were included in this randomized,blinded study. Four equal 3×6 mm bone defects were created on the frontal and parietal bones of each animal and three were immediately grafted with Bio-Oss®, Combi-Pack® and Biostite® while one was left untreated, serving as negative control. Histologic and histomorphometric analysis was performed four weeks after surgery.Results:
Histomorphometric bone area and trabecular maturity was significantly higher in the Bio-Oss® and Combi-Pack® samples as compared to the Biostite® and control cases.The amount of remaining biomaterial was almost equal in the three experimental groups at the end of the study period. Neither foreign body reaction nor severe inflammation was seen in any of the specimens except for the Biostite® samples.Conclusion:
It may be suggested that implantation of Bio-Oss® particles and Combi-Pack® blocks can promote bone regeneration more effectively than Biostite -
Objective:
There is no definitive data on the strength of glass fiber and cast posts with different length. This in vitro study was designed to investigate and compare the effect of length on the retentive strength of glass fiber and cast posts.
Materials and Methods:
Sixty recently extracted intact maxillary canine teeth were cut 1mm above the CEJ. The specimens were endodontically treated and randomly divided into four groups (n=15). Specimens in groups FP(9) and FP(12) were prepared using Fiber post with 9 and 12 mm in length while groups CP(9) and CP(12) used cast post with 9 and 12mm length respectively. The force required to dislodge each post was recorded as retentive strength. Collected data were statistically analyzed using two-way ANOVA and post-hoc tests (α=5%).Results:
The mean retentive strength of groups FP(9), FP(12), CP(9) and CP(12) were 203.74 (SD=38.46), 324.54 (SD=42.92), 156.82 (SD=32.69), and 210.73 (SD=54.60) respectively.The results revealed a significant difference among retention values of tested groups, except for the FP(9) and CP(12) (P<0.05).Conclusion:
Under the condition of this study, the retention of fiber posts was significantly more than cast posts with the same length. On the other hand, post length seems to have an impact on the retention of fiber and cast posts.
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Objective:
The purpose of this study was to evaluate the transverse strength of one brand of denture base material repaired with two autopolymerized acrylic resins with and without wire reinforcement.
Materials and Methods:
Eighty samples (2.5×10×65 mm3) were fabricated and divided into five groups. The control group was left intact. Groups B and D specimens were repaired with autopolymerizing acrylic resins. Groups A and C specimens were repaired with metal wire and autopolymerizing acrylic resins. After 48 hours of storage at 37°C, the transverse strength of the specimens was measured with a universal testing machine. Data were analyzed by one way ANOVA and Duncan test (α=0.05).Results:
Significant differences were found between the control group and the other experimental groups (P<0.05). Among experimental groups, group D showed the highest transverse strength with the mean value of 40.2 (SD=11.8) MPa while group B present the lowest transverse strength of 28.4 (SD=5.4) MPa. The difference between the transverse strength of group D and the other groups was statistically significant (P<0.05).Conclusion:
In wire reinforced groups, there was no significant difference between two types of acrylic resin (P=0.93), however in repaired groups without wire, the type of acrylic resin generates a significant difference in the transverse strength of the repaired specimens (P<0.05). The application of wire significantly reduces the transverse strength of the Meliodent repaired groups (P<0.05), however the changes occurred in transverse strength of the Acropars repaired groups was not statistically significant (P=0.28). -
Amyloidosis includes a wide range of disorders characterized by deposition of amyloid in different organs and tissues. Localized gingival enlargement due to accumulation of amyloid without involvement of other organs is a very rare condition. This article describes a 31-year-old male patient with amyloidosis involving only the periodontium of the anterior mandibular teeth with localized severe horizontal alveolar bone loss. To our knowledge this is the first case report that documents this condition.
