Al-Rafidain Dental Journal

Aims: The aim of this study was to evaluate the effect of mixing different concentrations of chlorhexidine, iodine ,and sodium hypochlorite solutions on the setting time and dimensional change of alginate impression material. Materials and methods: Total number of samples (40) has been prepared in this study. Ten samples for control group made from pouring alginate impressions of metal model .The other groups made by mixing alginate with 0.05% iodine, 0.5% chlorhexidine and 0.5% sodium hypochlorite solutions. Dimensional change was measured with AutoCAD program .The Setting time was also measured for each group. Statistical analysis was performed using ANOVA and Duncan multiple range test. Results: no significant difference in the linear dimensional change among the tested groups ,sodium hypochlorite added to alginate as disinfectant showed the highest dimensional changes among the other groups. There was a significant difference among the tested groups in the setting time. It was found that treating the alginate with sodium hypochlorite and chlorhexidine disinfecting agents accelerated the setting time of the material. Conclusion: The testing disinfecting agents can be used safely regarding dimensional change.

Aims: To compare between the effects of deproteinized bovine bone (DBB) and osteon in the healing of mandibular bone defects in the rabbits. Materials and Methods: This experimental study was conducted on ten rabbits at the Animal House, Dentistry college, Mosul University. The rabbits weighted between 1.5 and 2 kg and each rabbit was given anesthesia (10% ketamine (40 mg/kg) and 2% xylazine (5 mg/kg). Surgery was performed aseptically. Mandibles were exposed through a sub-mandibular incisions. Three rectangular full thickness defects (6×5 mm) were created in each side. The first defect in each side was filled with DBB, the second defect was filled with osteon, while the third defect was left untreated to serve as a control. Five rabbits were sacrificed after one week and the other five rabbits were sacrificed after one month. The bony mandibles were immersed in 10% formalin solution and examined histologically by two histopathologists. Results: Microscopically, sections for one week of all groups showed mild degree of inflammation, moderate amount of vascularity, granulation tissue and osteoid tissue formation. Sections of one month showed no difference regarding the degree of inflammation vascularity, but the amount of granulation tissue and osteoid tissue formation in the control group were lesser than the amount seen in both experimental groups. Conclusions: DBB and osteon accelerate bone healing after month regarding the amount of granulation tissue and osteoid tissue formation.

Aims: The aim of this study was to evaluate the shear bond strength of brackets bonded to composite restorations using four types of surface conditioning procedure. Materials and Methods: Thirty two cylindrical cavities were made at the center of self-cured acrylic resin blocks. All cavities were then filled with composite resin. The specimens were randomly divided into four groups. Group one: Composite surface was acid etched with 37% phosphoric acid. Group two: After using 37% phosphoric acid, bonding agent was applied and cured. Group three: After using 37% phosphoric acid silane coupling agent was applied then bonding agent was applied. Group Four: The composite surface roughened with a diamond bur, and then 37% phosphoric acid was applied. Brackets were bonded onto the composite prepared samples with Transbond XT. Shear Bond Strength was measured by a universal testing machine. KruskalWallis test was utilized for data analysis. Results: There was a significant difference between the four groups. The highest bond strength was that of Group 3. Group 1 had the lowest bond strength. Conclusions: Roughening the composite surface before acid etching was effective to improve the bond strength of orthodontic brackets to composite restorations. Addition of silane before bonding agent application result in highest bond strength.

Aims: the aim of this study is to determine a calibration factor to eliminate the distortion in the linear cephalometric measurements. Materials and Methods; the study was performed on the 5 dry skulls, the first skull contained 12 radiopaque markers fixed at different plains, and radiographed by digital cephalometric x-ray machine. The X and Y axes of the shadow of each radiopaque marker used to estimate the calibration factor. Eight linear distances measured directly and radiographically on the conventional cephalographs of the 5 skulls to evaluate the detected calibration factor. Results; the results showed no-significant difference (p > 0.05) between the direct and calibrated radiographic measurement on the digital and conventional cephalographs. whereas significant difference was found between the conventional cephalometric linear measurements as compared with direct anatomical linear and the conventional cephalometric linear measurements with those measurements manipulated with the estimated calibration factor (p < 0.05). Conclusions; this study found that the conventional cephalometric linear measurements could be reliable as that of digital cephalometric linear measurements, if it's calibrated by the calibration factor (1.08) which is estimated by the present study.

Aims: Hepatitis B virus infection is a global health hazard. The virus can be transmitted by both parenteral and non- parenteral methods such as direct contact with mucus membrane. Dental instruments can be the source of infection, therefore this study was conducted to detect HBs Ag in dental instruments used in the different public dental centers and clinics in Duhok governorate. Sampling process was from December 2016 to January 2017. Materials and Methods: A total of 549 samples were collected from five different districts as follow: 238 samples from center of Duhok, 121 samples from Zakho, 87 samples from Amedi, 68 samples from Sumail and 35 samples from Aqre. Four different commonly used dental instruments were chose namely: Scaler tips, curette, sickle and chisele. The samples divided into sterilized and used using capital A letter for sterilized and small a letter for used samples. Results: No HBs Ag was detected in all tested samples both sterilized and non- sterilized samples by ELISA technique. The results of the present study indicated to the proper hygienic precautions implemented in public dental centers and clinics as well as to the effectiveness of anti-HBV vaccine that almost all dentists had been received prior working. Conclusions: Further studies are required to cover private dental instruments as well as dentists and assistant technicians using both ELISA and RT-PCR techniques.