Vol 8, No 3 (2011)
Proceeding Abstracts
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Objective: Reinforcement with fiber is an effective method for considerable improvement
in flexural properties of indirect composite resin restorations. The aim of this in-vitro
study was to compare the transverse strength of composite resin bars reinforced with preimpregnated
and non-impregnated fibers.
Materials and Methods: Thirty six bar type composite resin specimens (3×2×25 mm)
were constructed in three groups. The first group was the control group (C) without any
fiber reinforcement. The specimens in the second group (P) were reinforced with preimpregnated
fibers and the third group (N) with non-impregnated fibers. These specimens
were tested by the three-point bending method to measure primary transverse strength.
Data were statistically analyzed with one way ANOVA and Tukey's tests.
Results: There was a significant difference among the mean primary transverse strength in
the three groups (P<0.001). The post-hoc (Tukey) test showed that there was a significant
difference between the pre-impregnated and control groups in their primary transverse
strength (P<0.001). Regarding deflection, there was also a significant difference among
the three groups (P=0.001). There were significant differences among the mean deflection
of the control group and two other groups (PC&N<.001 and PC&P=.004), but there was no
significant difference between the non- and pre-impregnated groups (PN&P=.813).
Conclusion: Within the limitations of this study, it was concluded that reinforcement with
fiber considerably increased the transverse strength of composite resin specimens, but impregnation
of the fiber used implemented no significant difference in the transverse
strength of composite resin samples. -
Objective: Attempts to treat class II malocclusions without extraction in non-compliant
patients have led to utilization of intraoral molar distalizing appliances. The purpose of
this study was to investigate dental and skeletal effects of Bonded Molar Distalizer
(BMD) which is a simple molar distalizing appliance.
Materials and Methods: Sixteen patients (12 girls, four boys) with bilateral half-cusp
class II molar relationship, erupted permanent second molars and normal or vertical
growth pattern were selected for bilateral distalization of maxillary molars via BMD. The
screws were activated every other day, alternately. Lateral cephalograms and study models
were obtained before treatment and after 11 weeks activation of the appliance.
Results: Significant amounts of molar distalization, molar distal tipping and anchorage
loss were observed. The mean maxillary first molar distal movement was 1.22±0.936 mm
with a distal tipping of 2.97±3.74 degrees in 11 weeks. The rate of distal movement was
0.48 mm per month. Reciprocal mesial movement of the first premolars was 2.26±1.12
mm with a mesial tipping of 4.25±3.12 degrees. Maxillary incisors moved 3.55±1.46 mm
and tipped 9.87±5.03 degrees mesially. Lower anterior face height (LAFH) decreased
1.28±1.36 mm.
Conclusion: BMD is appropriate for distalizing maxillary molars, especially in patients
with critical LAFH, although significant amounts of anchorage loss occur using this appliance. -
Objective: The goal of this study was to evaluate primary school teachers' knowledge regarding
emergency management of avulsed permanent incisors.
Materials and Methods: The study was conducted in fifty randomly chosen primary
schools from Casablanca, Morocco. All teachers of the selected schools were included in
the study. The data were collected by self administered questionnaires. The questions focused
on the teachers' general characteristics, experience of avulsed teeth and the importance
of emergency management. The data were analyzed using chi square test.
Results: A total of 501 teachers, of which 23.6% were male and 75.4% were female, answered
the questionnaire. The results showed that 44.5 % of the teachers had an experience
of avulsed tooth at school, 82.82% of them knew the importance of emergency management
and 32.6% would look for a dentist for treatment of the cases. Only 15.8% would
reimplant the tooth themselves. Regarding the storage media, 21.95% would keep the
avulsed tooth in milk. There was no significant difference between gender and education
level (p>0.05).
Conclusion: This study shows school teachers' lack of knowledge regarding dental trauma
and especially tooth avulsion. Therefore, the results indicated that educational programs
are necessary for improvement in their level of knowledge. -
Children suffering from decreased renal function may demand unique considerations regarding
special oral and dental conditions they are encountered to. It is mentioned that
renal function deterioration may affect the hard or soft tissues of the mouth. Having
knowledge about the high prevalence of dental defects, calculus, gingival hyperplasia,
modified salivary composition and tissue responses to the dental plaque may aid the physician
and the dentist to help nurture the patient with chronic renal failure through the crisis,
with an aesthetically satisfying and functioning dentition. -
Objective: One of the major problems of all ceramic restorations is their probable fracture against the occlusal force. The aim of the present in-vitro study is was to compare the effect of two marginal designs (chamfer & shoulder) on the fracture resistance of zirconia copings, CERCON (CAD/CAM).
MATERIALS AND METHODS: This in vitro study was done with single blind experimental technique. One stainless steel dye with 50’ chamfer finish line design (0.8 mm depth) was prepared using milling machine. Ten epoxy resin dyes were made, The same dye was retrieved and 50' chamfer was converted into shoulder (1 mm).again ten epoxy resin dyes were made from shoulder dyes. Zirconia cores with 0.4 mm thickness and 35 µm cement Space fabricated on the20 epoxy resin dyes (10 samples chamfer and 10 samples shoulder) in a dental laboratory. Then the zirconia cores were cemented on the epoxy resin dyes and underwent a fracture test with a universal testing machine (GOTECH AI-700LAC, Arson, USA) and samples were investigated from the point of view of the origin of the failure.
RESULT: The mean value of fracture resistance for shoulder margins were 788.90±99.56 N and for the chamfer margins were 991.75±112.00 N. The student’s T-test revealed a statistically significant difference between groups (P=0.001).
CONCLUSION: The result of this study indicates that marginal design of the zirconia cores effects on their fracture resistance. A chamfer margin could improve the biomechanical performance of posterior single zirconia crown restorations. This may be because of strong unity and round internal angle in chamfer margin.
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Objective: Low quality of the bone and insufficient bone due to the size of the sinus and
resorption of the alveolar ridge decrease the long-term survival of implants in the posterior
maxilla compared to other regions of the jaws. Surgical procedures to increase bone volume
make it possible to place implants longer than 8 mm. In this situation sinus elevation
makes it possible to place implants. We intend to evaluate peri-implant bone loss and survival
of implants placed in elevated sinuses after 2 years and to compare with implants
placed in the native posterior maxilla.
Materials and Methods:Twenty-five implants placed in sinuses that had been reconstructed
with Bio-Oss and healed after 9 months were compared with 30 implants placed
in the posterior maxilla without any surgery. The groups were compared using probing
pocket depth, bleeding on probing, Plaque Index and bone loss immediately after implant
placement surgery and 2 years postoperatively. The criterion for implant survival was
presence or absence of the implant in the oral cavity, which was recorded in relevant
forms in both groups.
Results: Three implants were lost; one in control and two in grafted sinuses. No significant
differences were observed in the survival rates. In general, the mean bone loss around
intrasinus and extrasinus implants was not significantly different. In the same context, no
differences were observed between bleeding on probing, Plaque Index and probing pocket
depths of two groups (P=0.397, P=0.637 and P=0.224, respectively).
Conclusion: The survival and bone loss around intrasinus and extrasinus implants are
similar. -
Objective: To study the in vitro color changes of three dental resin veneering materials
when immersed in tea, coffee and tamarind extracts.
Materials and Methods: The color changes of heat polymerized tooth colored acrylic resin
(Stellondetrey, B, F14, DPI Dental products of India Ltd, Mumbai), auto polymerized
tooth colored acrylic resin (DPI, B, QV5, DPI Dental products of India Ltd, Mumbai) and
light polymerized resin composite (Herculite XRV, Enamel A2, part no. 22860, lot no.
910437, Kerr Corporation, West Collins Avenue, Orange, CA, USA) when immersed in
water extracts of tea (Tata Tea Ltd. Bangalore, India), coffee (Tata Coffee Ltd. Coorg, India)
and tamarind were evaluated using computer vision systems. The color images were
recorded in R (red), G (green) and B (blue) form and converted into H (hue), S (saturation)
and V (value).
Results: Significant color change occurred for auto polymerized tooth colored acrylic resin
in tamarind extract, for heat polymerized tooth colored acrylic resin in tea extract and
for light polymerized resin composite in coffee extract. Auto polymerized tooth colored
acrylic resin samples showed an overall higher color change. However, for all the material
samples coffee extract produced more color change.
Conclusion: These results suggest that the color stability of the resins is influenced by the
presence of secondary metabolites such as tartaric acid, tannins, caffeine, saponins and
phenols in tamarind, tea and coffee extracts. -
Mandibular defects may result from many conditions such as trauma, inflammatory
diseases and tumors. There are rare cases reported in the literature that have demonstrated
spontaneous bone regeneration after resection of the mandible. Several
factors such as age, preservation of the periosteum and genetics seem to influence
spontaneous bone regeneration capacity in individuals. Evaluation of these factors
may lead to a better understanding of the mechanism of spontaneous bone regeneration
and also help to create new methods for bone reconstruction. The purpose of
this article was to describe the spontaneous regeneration of the hemi-mandible with
a well shaped condyle and coronoid after resecting a mandibular pathologic lesion
in a young man.
