MUSTANSIRIA DENTAL JOURNAL

Background: this study was conducted to compare the centering ability and canal transportation of: Protaper, Mtwo, WaveOne, Reciproc in simulated curved canals.
Materials and methods: Eighty simulated curved canals of 40° curvature were divided into four groups and prepared to an apical size 25 using a crown-down technique for ProTaper instruments and single length technique for Mtwo
instruments and single file technique for WaveOne and Reciproc instruments. The following parameters were evaluated: outer and inner canal transportation and the centering ability. The measurements were carried out at five different levels. Pre-and postoperative images of the canals were taken at 40X magnification byaid of stereomicroscope. An assessment of the canals shape was determined using Photoshop CS2 and AutoCAD software. The data were analyzed statistically using ANOVA and LSD test.
Results: Considering canal transportation, the direction of transportation of rotary NiTi instruments was usually toward the inner aspect at middle parts of the canal and toward the outer aspect of the curve at the apex of curve and the end of preparation. Waveone and Reciproc files were showed a better maintaining its original curvature with less straightening and transportation especially at the end of preparation of simulated canals. WaveOne and Reciproc instruments obtained
better centering ability at all levels especially at the end point of preparation comparing with Protaper and Mtwo instruments.
Conclusions: WaveOne and Reciproc instruments maintained the original curvature significantly better than ProTaper and Mtwo.

The aim of this study was to compare apical microleakage of MTA following
reverse retrograde root filling with that following Alumina Cement, Light Cement,
Zenium HMP retrofilling. The root canals of 42 extracted teeth were instrumented and
obturated with vertically condensed gutta-percha. Each tooth was apically resected
and the apex was prepared by fissure bur to 2 mm depth and the root surface isolated
with nail varnish. Teeth were divided randomly into four groups of 10 teeth each.
First group was retrofilled with MTA, second group with Alumina Cement, third
group with Light Cement, and the fourth group with Zenium HMP. Following
immersion in 2% Fuchsine dye for 72 hours, the roots were sectioned and the depth of dye penetration was evaluated by a Global stereomicroscope at x70 magnification.The sealing effectiveness of the retrograde filling materials was determined by their ability to inhibit dye penetration. Results showed that the least leakage for zeniuum HMP cement with a mean of 0.6, MTA with a mean of 1.0, light cement with a mean of
1.10, alumina cement with a mean of 1.50 with the most leakage. However, these differences were not seen to be statistically significant using the Kruskal Wallis Test or the Mann Whitney Test. It was concluded that Zenium HMP cement provides a better seal than MTA and Light Cement and Alumina Cement when used as retrograde filling.

The success of metal-ceramic restorations is influenced by the compatibility between base metal alloys and porcelains. Although porcelain manufacturers recommend their own metal systems as the most compatible for fabricating metalceramic
prostheses, a number of alloys have been used. The purpose of this study was to evaluate the bond strength of CoCr alloy (Wironbond C) and NiCr alloy (Wiron 99) using shear forces at the metal-ceramic interface. A stainless steel cylindrical matrix
was used for preparation of the metal dies, application of ceramic and to perform the shear tests. Ten metal dies of each alloy were made for each alloy, and the metallic portion was obtained with the lost wax casting technique with standardized waxing of
6.5mm of height and of 6mm of diameter. The ceramic was applied according to the manufacturer’s recommendations with the aid of a Teflon matrix that allowed its dimension to be standardized in the same size as the metallic portion, and shear tests were performed in a universal testing machine at a cross-head speed of 0.5mm/min.
The mean shear bond strength values were 53.06MPa for Wirobond C alloy, with standard deviation of 10.67, and 45.38MPa for Wiron 99, with standard deviation of 9.01. No statistically significant difference was observed between the shear strength of the two metal-ceramic alloys.

All-ceramic materials, especially silica-based lithium di-silicate and non-silicatebased
Zirconia have become a topic of interest in the field of dentistry. It is still
difficult to achieve a strong and durable resin-ceramic adhesion, especially resin-
Zirconia bonding, focusing on the latest resin bonding techniques including surface
treatment, priming and cementation.
The purposes of this study was to evaluate the effect of different surface
treatments on shear bond strength of zirconia bonded to dentin with two resin luting
cements.A total 60 zirconia discs 3mm thickness and 6 mm diameter subjected to
three types of surface treatments,irradiated with CO2 laser,etched with hydrofluoric
acid, sandblasted+ceramic primer application,then bonded to dentin with two types of
resin cement (variolinkII and Dentocem). Shear bond strength was measured and the
type of failures were determined. The data were statistically analyzed by one-way
analysis of variance and Independent T-test. The results of this study showed that the
groups which were sandblasted treated with ceramic primer produced highest shear
bond strength followed by hydrofluoric etched groups and CO2 laser irradiated groups
showed the lowest bond strength. Dentocem resin cement showed better bonding than
variolink II.The failures were either adhesive (between discs and cement)or
cohesive(cements on both disc and dentin).As a conclusion the bonding of Zirconia
can be improved by the different surface treatments especially by sandblasting
ceramic primer . Dentocem resin cement showed higher shear bond strength than variolinkII so promoted better adhesion between dentin and zirconia.

Background and objectives: The aim of root canal obturation in endodontic
treatment is to prevent communication between the oral cavity and periapical tissues. Several techniques had been introduced to achieve complete filling of the root canal system. It had been noted that more researches are needed to establish
standard techniques of root canal filling, and all the techniques should be
compared for filling root canals. The aim of this study was to compare the apical sealing ability of three different obturation techniques.
Methods: Thirty single rooted teeth were collected and randomly divided into three groups. There were 10 teeth in each group. The teeth were obturated by gutta percha as follows: Groups 1 with Thermafil, Groups 2 with Soft core, and Groups 3 with System B. The apical leakage in these groups was evaluated using a dye penetration method.
Results: The lowest mean rank of leakage was observed for system B and the highest
was observed for the thermafil groups. The difference between Thermafil, soft core and system B was statistically not significant by using Kruskal Wallis test.
Conclusion: System B obturation technique show less microleakage than soft core and thermafil techniques although the differences was not significant.

The purposes of this in vitro study were to compare the marginal adaptation, internal fitness and the microleakage of three CAD-CAM all ceramic crowns
materials: Zolid, Zircon, and Empress 2. This study also evaluated the correlation of
microleakage of these ceramic crowns materials to the marginal fitness.
Forty-five maxillary first premolar teeth were prepared with 2-mm occlusal
reduction and 1-mm all around shoulder finish line, teeth were randomly divided into three main groups according to the type of ceramic material that was used (n=15).
Group 1: received a CAD-CAM Ceramill Zolid® unilayered transparent zircon Group
2: received a CAD-CAM Ceramill ZI units (Zirconium oxide) Group 3: received a
CAD-CAM Ceramill wax units that would subsequently invested and heat pressed to
fabricate a hot-press ceramic crowns.
The results showed statistical significant difference in marginal fitness, internal
fitness and microleakage between Zolid group and other groups (P>0.0001). There
was highly significant correlation of the marginal and internal fitness, whilst there was no significant correlation marginal fitness and microleakage.

Background: The fracture of instruments within root canal during endodontic
treatment is a common incidence, fracture of fatigue through flexure occurs
because of metal fatigue, NaOCl used for irrigation may have an effect on
corrosion that decrease fracture resistance. This study aimed to assess the effect of
NaOCl temperature on the cyclic fatigue of different type of Endodontic NiTi
Rotary Instruments and compare among them.
Materials and method: three types of rotary instruments with tip size 0.25: ProTaPer
F2 (Densply,Malifier) Revo-S SU ( 0.06 taper, MicroMega) and RaCe system
(0.06 taper, FKG,Dentaire), Thirty file of each instrument type were used within
canal with 60° angle of curvature , undiluted NaOCl (5.25% ) were used. Ten file
without immersion in NaOCl, ten were immersed at room temperature (21°C) for
5 minute and ten with immersion in NaOCl at 60°C for the same time. Nine group were formed for all instruments (total number=90). The testing canal customized
within stainless steel block covered with glass face, the time to fracture recorded and the mean of cycles to fracture (MCF) detected for each instrument .Data were analyzed statistically by ANOVA, LSD and Independent T-test at 5% significant level.
Result: there was a highly significant difference in mean of cycles to fracture for each
rotary instrument when temperature of NaOCl increased that the Number of cycles
to fracture decreased as the temperature increased. RaCe revealed the best fracture
resistance followed by ProTaper then Revo-s that showed the less resistance.
Conclusion: the rotary instruments more prone to fracture when temperature of
NaOCl increased, as well as the rotary instruments differ from each other
according to manufacturing process, taper, cross section and other factors.

This in vitro study evaluated and compared the apical sealing ability of two
obturation techniques and two type of instrumentation. A total of 120 teeth were
collected randomly divided into two groups 60 roots prepared using hand protaper, other 60 roots prepared using rotary protaper .Each group was subdivided randomly into two obturation groups of 30 roots for each; in group A- obtura II was used ,and in group B-thermafill (TF) was used. Then the samples in all groups left for a week at room temperature. After coronal sealing, all surfaces of the root covered with three layer of nail polish except the apical 2mm, then each sample immersed in 10% black Indian ink dye for 72 hours .After that the samples rinsed and nail polish removed
.then samples cleared & decalcified.Data had been collected from independent examiners and statistically analyzed using student t-test. The stereomicroscopic
results showed that there was highly significant difference between hand and rotary
instrumentation, with in favor of rotary instrumentation technique. Concerning the obturation techniques, Thermafill showed best apical sealing followed by Obtura II; however, the differences were not significant.

The purpose of this study was to assess the position of impacted lower third
molars, the indications for extraction, and the post-operative complications. Records
of patients who attended Misan general hospital between March 2008 and April 2009 for surgical removal of mandibular third molars.
The angulation type and depth of impaction were determined by reviewing the orthopantomograms. A total of 140 impacted teeth were surgically extracted from 132 patients (69 males, 63 females). The reasons for extraction include recurrent pericoronitis (55%) followed by caries (25%) and prophylactic purposes (20%).
Mesioangular impactions accounted for (49.29 %) and Level 1 position of
impaction accounted for (65%) of extractions. 40 complications (28.57%), including persistent pain and swelling, infection, dry socket, Trismus and ulceration were reported . Persistent pain and swelling was the most common complications followed by infection. There was no significant relationship between the angulation, level of impaction and the occurrence of complications. Mesioangular type and Level A position of impaction were the most common impaction. Although the association was not significant, high frequency of post-operative complications was observed in mesioangular, horizontal and level A position of impaction.

Gender stereotypes can lead to a variety of generalizations that affect the
perceptions of patients. Pain mechanism start with peripheral stimuli which will
initiate the afferent nerves fibers that will transmit the signals towards the central
nervous system through the spinal cord into the cerebral cortex where the pain signal
will be translated.
The aim of this research is to evaluate the complex assessing of patient’s pain
perception in relation to the gender of the dentist during normal teeth extraction.
Samples in this study was composed of (50) patients, divided into two equal
groups, first group treated by male students and the second’s group treated by female
students.
The results of statistical analysis of data showed that pain perception by the
patients was in mild status more in male group 18(72%) than female group
4(16%),While in moderate was less in male group 5(20%) than female group
15(60%),and in sever also less in male group 2(8%) than female group 6 (24%). A significant difference was shown between the two students' gender in case of moderate and sever pain status (Chi-square in moderate status 8.33 & p-value= 0.004 while in sever status 2.381 & 0.048respectively), while high significant difference in
mild status (Chi-square15.91and P<0.01).
In Conclusions: A statistical analysis showing that pain perception experienced by the patients treated by male students’ operator liable to be less than those treated by female students’ operator.

The purpose of this study was to evaluate the relationship between
temporomandibular disorders, mood status and serotonin transporter (5-HTT) genepolymorphisms in Syrian population. Twenty patients with temporomandibular joint disorder (TMD), and 36 healthy control subjects were examined. The sample consists
of 23 males, and 33 females aged between (19-30 years old), visited the department of
fixed prosthodontic of the faculty of dentistry, Damascus University. This study
shows that S/L allele of 5-HTTLPR was the most frequently observed allele in TMD
patients; whereas statistical analysis did not show significant difference between
patient and control groups by neither genotype distribution analysis nor allele
frequency analysis. SS allele analysis showed a relation between it and mood status. Although the study did not show significant relation between TMD and serotonin transporter polymorphism gene, but according to the importance of serotonin transporter polymorphism gene and its relation to psychological factors we suggest other studies which focus on the relation between the genetics, psychology and TMD.

Objective:-The presence of specific type of blood group antigens have been
associated with various diseases, with antigens also acting as receptors for
infectious agents and the relative susceptibility of some blood group phenotypes to
certain oral diseases has been investigated. Also, the poor oral health and develop
of some oral disease has previously been related to high body mass index (BMI).
Aims of the study :-The the aim of this study was to indicate if any association
between ABO blood system and body mass index with several oral diseases
includes gingivitis and periodontitis.
Material and method :-A total of (82) subjects were included in this study collected
from hospital of dentistry college from February to July,2013,divided into three
groups as those with gingivitis, periodontitis, and the healthy ones consider
control group, aged between (10 and 55 )years were selected on a random basis .
ABO blood groups were detected by using slide agglutination method after
collected of blood samples .BMI was measured for all groups.
Results: The results of this study reported that blood group type (O) appear in high
percentage ( 50%) among patients group include( gingivitis and periodontitis ),and
the blood group (A)showed a high percentage ( 47.67%) in healthy group with
statistical significant differences (p <0.05) while, the least rate of blood group in
oral disease group were (AB)( 7.5%) and ( O and B)(14.29%) in control. The
results of RH factors showed a significant increase of Rh-positive in all examined
groups. The body mass (mean ±SD) (26±3.056) kg/m2was significantly higher
patient group when compared to control(BMI= 22.71±3.241) kg/m2 with p
value< o.o5 .while the statistical analysis revealed there were non-significant
differences according to type of blood groups between male and female and the
mean of BMI not differed between gingivitis and periodontitis p>0.05.
Conclusion: Significant relationships between ABO blood type and body mass index
with most common oral disease while RH results revealed no significant
differences were recorded between control and oral disease.

Background: Bone morphogenetic proteins (BMPs) are secretory signal molecules
which have a variety of regulatory functions during morphogenesis and cell
differentiation. Teeth are typical examples of vertebrate organs in which
development is controlled by sequential and reciprocal signaling between the
epithelium and mesenchyme. In addition, tooth development is characterized by formation of mineralized tissues, dentin and cementum as well as epithelially derived enamel. BMp 7 plays a role with other signaling molecules in tooth
development.
Aim of the study: To perform immune-histochemical analysis of the expression of
BMP7starting from initiation of tooth development to completion of crown
morphogenesis when dentine and enamel matrices are being deposited in rat
incisor tooth Materials and Methods: Sixteen rat embryos were obtained from pregnant rats in gestation periods 16th,17th,18th,20th intrauterine life and eight neonatal one day and 3 day old rat were included in this study . Each period involved 4 embryos or neonatal rats. Premaxilla ( containing incisor teeth) was dissected and fixed in 10% buffered formalin and embedded in paraffin. Block sections (4 μm thickness) for Immunohistochemical localization of BMP7.
Results: Positive expression of BMP7 was recorded in ectoderm derived cells only, in
developing tooth germ include oral epithelia, dental lamina and inner enamel epithelia in gestation period 16th,17thand 18thintrauterin life of rat embryo. Then the expression was illustrated in specialized cell of dental papilla the odontoblast and the developing dentin matrix .Ameloblast cell expressed too BMP7 in its formative and maturative stages.
Conclusion: Bone morphogenetic protein 7 may play key roles in mediating induction, differentiation events during tooth development.

Background: Oral squamous cell carcinoma is an aggressive malignancy. It arises
from premalignant lesions followed by outgrowth of clonal cell populations with
cumulative genetic alterations. Phosphoinositol 3-kinases are a family of related
intracellular signal transducer enzymes capable of phosphorylating the 3 position
hydroxyl group of the inositol ring of phosphatidylinositol (PtdIns).
Phosphatidylinositol-3-kinases involved in cellular functions such as cell growth,
proliferation, differentiation, motility, survival and intracellular trafficking, which in turn are involved in cancer. RAS is a signal transduction protein for many important cellular processes such as cellular proliferation, differentiation, andsurvival by mediating the cell's response to extracellular stimulations. Kras, is aprotein within the RAS family, function in the same pathway of a Ras –Raf -Mek-Erk-map kinase pathway which plays a role in mediating cellular response to cell growth. Kras appears to be involved in signal transduction and cell cycle
regulation. To dates there has been limited previous investigation of protein expression of both PI3Kcb and Kras in oral squamous cell carcinoma. This study was performed to examin the expression of PI3Kcb and kras in oral squamous cell
carcinoma in comparison to normal oral mucosa and to correlate the expression of both markers with clinicopathological findings including tumor grade and stage and with each other.
Materials and Methods: This study included 31 selected cases of oral squamous cell carcinoma pro and retrospectively and 10 cases normal oral mucosa. PIK3cb and
Kras expression has been detected by immunohistochemistry.
Results: Results of the present study revealed positive PI3Kcb and kras expression in all examined oral squamous cell carcinoma cases. Immunostaining results for kras
& PI3kcb were detected as brown stain for cell membrane and cytoplasm in tumor cells while there was no expression of both markers in normal oral mucosa. Nosignificant correlation was observed between both markers and the
clinicopathological finding of oral squamous cell carcinoma while highly
significant positive correlation was observed between the two markers.
Conclusion: The Present study provides additional evidence that Kras, and PIK3cb
over expression are common in contribution to oral squamous cell carcinoma tumorigenesis, and that PI3Kcb signaling network plays an important role in oral squamous cell carcinoma and thus, pathway-specific therapies targeting these two pathways should be considered in the future treatment of oral squamous cell carcinoma patients. MDJ

This study aims to investigate the role of using dried Human Amniotic Membrane (dHAM) on rabbit's oral mucosal wound healing in its early stages. Six male rabbits were used in this study. In each rabbit, two elliptical incisions were done on both sides of tongue dorsum; one of them was left uncovered and the other was covered by
dHAM. The animals were divided into two groups with three rabbits each according
to the sacrifice periods which were three days and one week. After sacrifice, histopathological examination was performed to assess re-epithelialization and
inflammation. Within the first three days, the re-epithelialization was much more
faster in dHAM group than that in control one, and the difference between the control and study group was statistically highly significant ( p=0.005 <0.01). Moreover, the rate of inflammatory process show significant difference between the two groups with
advantage to HAM group (p =0.046 <0.05). However, after one week, this difference
was statistically non-significant ( p =0.317 > 0.05). Human Amniotic Membrane
could be considered as an option to enhance oral wound healing especially in its early stages.