Tikrit Journal for Dental Sciences

Sjögren\'s syndrome (SS) is a chronic inflammatory disorder of the salivary and lacrimal glands that leads to functional impairment. Hypofunction of salivary glands is the main cause of oral pathological changes and is associated with alterations in the constituents of the saliva.This study aimed to test the hypothesis that proteomic approaches markers (notably peptides) are involved in the oral manifestations observed in Sjögren\'s syndrome (SS).A total number of 71 participants were admitted in the study; 21 of them have Sjögren\'s syndrome (Group I), 43 non-Sjögren\'s syndrome cases referred or attended the dental clinic seeking for certain management (Group II) and 7 apparent healthy subjects without dental problems (Group III).Stimulated saliva was collected from each patients and participants for biochemical analysis including assessment of salivary protein and peptides.Salivary flow rate was significantly (p<0.01) reduced in SS patients by 33.4% and 24.1% of corresponding Group II and Group III respectively. The salivary protein concentrations (total albumin and peptides) per milliliter saliva fluid were increased in SS patients. Saliva peptides (2.09±1.01 mg/ml)level was significantly (p<0.05) higher than Group II (1.708±0.649 mg/ml) and Group III (1.339±0.517 mg/ml).Hypofunction of salivary glands in SS is associated with significant changes in the salivaconstituents particularly the peptides.

Root and crown resorption is a physiologic event for the primary teeth. It is still unclear whether odontoclasts, the cells which resorb the dental hard tissue, are different from the osteoclasts, the cells that resorb bone. Dental tissue resorption seems to be initiated and regulated by the stellate reticulum and the dental follicle of the underlying permanent tooth via the secretion of stimulatory molecules, i.e. cytokines and transcription factors. The primary teeth resorption process is regulated in a manner similar to bone remodeling, involving the same receptor ligand system known as RANK/RANKL (receptor activator of nuclear factor-kappa B/ RANK Ligand), which represent two cytokine-like proteins of the tumor necrosis factor superfamily, are localized on bone cells and dental cells .They are crucial for the regulation of osteoclastic/odontoclast cell differentiation and also for the upregulation of mature osteoclasts/odontoclasts mediated by cell-to-cell contact and a subsequent cascade of diverse intracellular signaling processes .The aim of the present study was to localize and compare the IHC reactions for RANKL along root surface and the crown of human phsiological resorbed primary teeth. Fifteen human upper deciduous (second molar) teeth ,undergoing root and crown resorption were used for immunohistochemical study to identify RANKL expression.The results demonstrated a high mean of expression of RANKL in root as compared with crown in human primary shedding teeth.The present study concludes that RANKL play a role in resorption process of the primary teeth.

The objective of this study aimed to assess the caries-preventive potential of various CW CO2laser parameters, and to explore the effect of the laser power density on the caries inhibition activity.Extracted human deciduous molars were irradiated with three various power densities, by changing the output power, the exposure time, and the spot diameter. The CO2laser system emitted laser with 10.6μm in wavelength. All teeth were subjected to carieslike lesion formation by 3.5 pH lactic acid for 21 days. The teeth after that were sectioned into ground cross sections and the lesion depths were measured under a polarizing microscope.CW CO2 laser preventive treatments inhibited carieslike lesion progression up to 82%. This effect was improved with increasing power density within the limits of the examined laser parameters.

The aim of this study was to assess the incidence of two rootcanals in the mesial root of the extracted permanent maxillary first molars of a Sulaimani population. An ex vivo study on 180 extracted permanent maxillary first molars was conducted. The teeth were examined clinically and radiographically. The results showed that 23.3 % of the examined teeth had two canals in the mesial root (17.0 % with one apical foramen and 6.3 % with two separate foramens).

Widespread use of prefabricated post that provides retention and support for core and the final crown has caused manufacturers to produce different types of post materials. The aim of this study was to evaluative the fracture resistance of two types of post materials and two types of core material. Forty extracted human mandibular premolar were selected. After root canal preparation and obturation with gutta percha the roots were divided into two groups according to the type of post material, group F restored with fiber post and group T restored with titanium post then each group was subdivided into two subgroup according to the type of core materials which include composite and amalgam restorative materials. Then all the teeth were subjected to compressive load at 130oangle from the horizontal plan at a 5mm/min crosshead speed until fracture. Results showed that there was significant different between groups in term of fracture loads (P= 0.0156). Also the fracture loads of teeth restored with titanium post andcomposite core has highest mean fracture load (812N), whereas teeth restored with fiber post and amalgam core demonstrated the lowest mean fracture load (643.1N). The study concluded that the teeth restored with metal titanium post were more fracture resistant than those restored with fiber posts. But the combination of a fiber post and composite core has the favorable mode of fracture that considered reparable, while considered unfavorable when restored with titanium post.

The study aims to evaluate and compare the microleakage of three different lutingmaterials. The materials compared areZinc phosphatecement, Variolink II Refilland Glass ionomer resin cement.Eighteen recently extracted caries-free wisdom teeth were used . The teeth were cleaned then stored in distilled water until use. The molars were assigned randomly into three groups of 6 teeth of each .Themetal ceramic crowns were constructed by means of an indirect laboratory technique. In group A, the crowns were cemented with a traditional Zinc Phosphate. In group B, the tooth preparations were sealed with VariolinkII Refill. In group C, the tooth preparations were sealed with glass ionomer resin cement prior to cementation with the crowns.The results showed highervalue of microleakage forZinc phosphate cement. While the least value was for the Variolink II . The value for Glass ionomer resin cement was low. Statisticallyanalysis revealeddifference between the Zinc phosphate cement ,Variolink II andGlass ionomer resin cement in microleakage. There was no significant difference in microleakage between Variolink II and Glass ionomer resin cement. This may indicated that the degree of microleakage may influenced by the type of theluting system used.

The purpose of this study was to examine the effect of altering surface topography on the biaxial flexural strength (BFS) of four dental ceramics, Mirage (MI), Flexoceram (FL), Optec-HSP (OP) and IPS Empress (EM).Twelve groups of ten discs 123mm were prepared and fired according to the manufacturers\' instructions. Ten specimens of each material were subjected to three surface treatments, polished, grit blasted and etched with 10% hydrofluoric acid (HF) for 2 minutes. Some specimens were gold coated for examination under Scanning Electron Microscope (SEM). BFS was determined using Lloyd M5K universal testing machine at a cross-head speed of 0.5 mm/min. A one-way ANOVA was used to evaluate the differences between groups.The results obtained showed that the only significant difference in the BFS was the 10% HF for OP and FL (One-way Anova, P<0.05). The decrease in BFS is most likely due to an increased surface flaw size, such that surface initiated crack growth dominates over the bulk internal flaw size of the ceramics.The BFS of dental porcelain used in this study may be governed either by the internal or surface flaws depending on the manner of surface preparation. Specimens etched with 10% HF became weaker for OP and FL ceramics.

The study aims to evaluate the effect of some commercially available natural products (soda+ vinegar, soda +thymol , saturated salt solution) in relation to the commercial denture cleansers (Protifex) ,on surface roughness and hardness dimensional accuracy of acrylic denture base materials.one hundred samples were prepared from heat activated acrylic resin denture base material, they are (1cm*1cm*2mm length, width and thickness respectively). After that, half of the samples for each group were immersed for ½ hr per day in the denture cleanser, the other half of the samples immersed for 8 hr per day in the denture cleanser through one month. The denture cleansers used are three solutions prepared freshly everyday for immersion of the samples. The surface roughness of the samples were tested by using Stylus profilometer(Talysurf 10, England), while the hardness of the samples were tested by using Rockwell hardness tester (Wolpert, Germany), the mean is taken for each group and evaluated by using one way analysis of variance test, Dunnet T-test to compare the groups.The results demonstrated that there were no significant differences in the surface roughness and hardness, but with significant difference between treats of length of acrylic resin denture base material and duration of immersionat (P=0.05). All the prepared natural solutions would be accepted in relation to effect on surface roughness , dimensional accuracy, and hardness of acrylic denture base material.

Autopolymerizing acrylic resin is one of the most frequently used materials in dentistry, but it has relatively poor mechanical properties This study investigated the effect of the addition of poly vinyl pyrrolidone on transverse strength, impact strength and surface roughness of autopolymerzing acrylic resin. A total of 60 specimens were prepared, 30 specimens of each conventional and modified autoplymerizing acrylic.20 specimens of each groups were fabricated with dimensions of (64×10×2.5) mm to conduct the transverse strength and surface roughness tests, while the remaining 10 specimens of each group were fabricated with dimensions of (80×10×4) mm to perform the impact strength test. The results of this study showed that the modified autopolytmerized acrylic had significantly higher transverse strength, and significantly lower surface roughness values while there was no significant differences in impact strength value. It can be concluded that addition of Polyvinylpyrrolidone can improve transverse strength and surface roughness of autopolymerizing acrylic resin.

This work involves study the effect of tobacco smoking (cigarette, water-pipe smoking) yields on the corrosion of dental alloys (Co-Cr-Mo, Ni-Cr and Ti-Al-V alloy) in artificial saliva with pH=4 and temperature of 37oC. This study was performed with electrochemical technique by using potentiostat to predict the potentiodynamic polarization and cyclic polarization. Some corrosion parameters were measured for comparison among the dental alloys.Generally, the presence of tobacco smoking yields shift the corrosion rate (CR) to higher values, and the data of corrosion rate indicate that the risk of waterpipe smoking more than cigarette smoking for three dental alloys.Increasing of anodic Tafel slopes inferred that the rate of change of current with change of potential was smaller during cathodic polarization than during anodic polarization.

Mandibular third molars are appeared to be the most common congenitally impacted teeth the fact that may cause many problems in different fields of dentistry. surgical removal of the impacted tooth seems to be the only solution for these problems. An important complication to address is the risk of developing periodontal breakdown ( loss of attachment) and deep periodontal pocket on the distal aspect of the adjacent mandibular second molar after surgical removal of third molar. The aim of the present study is to evaluate and compare the effect of 4 suturing techniques: (Simple loop , Figure 8 suture, Anchor suture and Closed anchor suture) on the periodontal health status on the distal aspect of the adjacent mandibular second molar after surgical removal of lower impacted third molar.Forty patients having fully impacted mandibular third molars were enrolled in this study and divided to 4 groups (Group A: Simple loop , Group B: Figure 8 suture, Group C: Anchor suture and Group D: Closed anchor suture), each group consisted of 10 patients. Surgical extraction of impacted third molars were carried out for them. Probing pocket depth (PPD) and clinical attachment level (CAL) were recorded preoperatively and 6 months after surgery. On 6months after surgery the mean values of PPD and CAL were significantly increased on the distal surface of the adjacentmandibular second molar in simple loop & figure 8 techniques. On the other hand, no significant difference has been noticed between anchor & closed anchor techniques in comparison with preoperative values. After 6-months, PPD and CAL values of were significantly higher in thesimple loop and figure 8 techniques compared to anchor andclosed anchor techniques. The present study concluded that closedanchor suture & anchor suture techniques are preferable to closethe flaps in surgical removal of impacted mandibular third molarsto maintain a good health status on the distal side of the adjacentmandibular second molar.

This study concerns with the incidence of dry sockets among a sample of patients attending different dental clinics after tooth extraction for three consecutive years in relation to their age, sex, tooth location and to patients perceived stress.Dry socket patients records were investigated for age, sex and tooth location. And a control group was chosen of exactly the same age and sex distribution as that of the patients but free from any symptoms . A questionnaire sheet with a list of possible life events for the last twelve months before the extractions were distributed among both, then the results was subjected to statistical analysis.Out of 956 patients,58 (6%) developed dry sockets, (36%) of them were located on wisdom teeth with the lower ones comprising (25.86%). There were significant difference in mean perceived psychological stress between the patients (477.07 ± 7.38 L.C.U) and those in control group (240.44 ± 7.12 L.C.U.) regarding different ages and sexes.There were higher incidence of dry sockets in this study than most other studies around the world and female /male ratio was nearly equal. They occurred mostly on lower and posterior more than upper and anterior teethwisdom teeth were most, highly affected, and there were a relationship between psychological stress and dry socket.

The purposes of this study was to investigate the effect of sodium hypochlorite (SH) and chlorhexidine (CH) disinfectant solusions on surface texture and mechanical properties of gutta percha (GP) cones at different concentrations and time intervals. In this study, 190 GP cones size 100 were used. SH solutions at (1%, 2.5%, 5.25%) and CH solutions at (1%, 1.5%, 2%) were used for GP cones disinfection by submerging cones for (10 min, 15 min, 20 min) in each of the solutions to be tested, in which 10 cones were used for each disinfectant solution at every time interval, and 10 cones remain fresh as a control. Surface texture determined by stereomicroscope. Mechanical properties measured by digital universal testing machine.SH solutions at (2.5% and 5.25%) decrease tensile strength, increase modulus of elasticity, decrease percentage of elongation , and left a numerous pitting on GP cones after (10, 15, 20) minutes of disinfection which were significantly different from fresh control cones, 1% SH , and CH at (1%, 1.5%, 2%).Within the limitations of this study, SH at 1% and CH at (1%, 1.5%, 2%) concentrations can be considered the most safe solutions for disinfection of GP cones.

The shape of the mandibular notch (mandibular incisure) of both sides of 100 fresh macerated and dry adult human mandibles divided between 58 males and 42 females of Iraqi origin with their age ranges (23-52) years that had been studied in order to classify the variations in the shapes of mandibular incisure.Three types were evident: type I triangular shape, type II rounded shape and type III truncated quadrilateral shape. The triangular shape mandibular notch were found in 92 (46%) sides and truncated quadrilateral shape in 40 (20%) sides, they are mainly prevalent in male, while the rounded shape was founded in 68 (34%) sides mainly prevalent in female.Minor differences appeared on both sides founded in 28 sides but keep the general shape. The incidence of the rounded types was almost in female mandible while triangular &truncated shapes were faced mainly in the male mandibles.