Abstract: Aims: The aim of this study was to evaluate the effect of the natural denture cleanser saturated salt solution on disinfection of C. albicans for the maxillary complete denture (An in vivo study). Mate-rials and Methods: An in vivo study testing anti fungal efficiency of the natural denture cleanser satu-rated salt solution on disinfection of C. albicans for 60 patient wearing maxillary complete denture by using light microscope with camera and connected to computer. The swab was taken from the fitting surface of the denture of about 2.5 cm following the median line starting from incisive papilla. This study compared the effect of disinfection between before and after immersion in distilled water (Con-trol), saturated salt solution (Iraq), and protefix(Germany). Results: The results demonstrated that there were significant differences between salt solution and distilled water, that there were no signifi-cant differences between salt solution and protefix at p=0.05. Conclusions: saturated salt solution was very efficient for disinfection of C. albicans for acrylic denture base material.

Abstract: Aims: The aim of this study is to evaluate the biological activities of three soldering materials used for joining Co-Cr joints (iron, stainless steel, and brass) on the tissue of the Rabbit. Materials and Meth-ods: Nine specimens of each iron, stainless steel, and brass where made as cylinders (3mm x 2.5mm). The middle part was made of the brazing materials and the upper and lower parts were made of Co-Cr. These specimens where implanted in the subcutaneous tissue of the rabbit, after two weeks the animals where sacrificed and biopsies where made and examined under microscope by three oral pathologists. Results: Stainless steel implants were the most biocompatible material among the three materials used as brazing materials. Stainless steel sites had insignificant differences with the control sites. Significant difference was found between the iron implanted sites and the control group. This result found by two viewers (A, and M), while the third viewer (Z) found no significant difference between the control group, and the iron implanted sites. Significant difference was found between the brass implanted sites and the control group, this result was found by the three viewers (A, M, and Z). Conclusions: The stainless steel had the most favorable tissue response among the three soldering materials, iron is in the second rank, and brass showed unfavorable tissue response due to release of Cu.

Abstract: Aims: Aim of the study is to evaluate some physical properties of locally prepared dental stone form natural gypsum by two different calcination methods with autoclave with and without adding crystal habit modifier during calcination procedure for different periods of time. Materials and methods: The values of some physical properties that include specific gravity, water/ powder ratio and linear setting expansion of the prepared dental stone with autoclave with and without adding crystal habit modifier during calcination procedure for different periods of time and compared with that of commercial den-tal stone. ANOVA and Duncan's multiple range test were performed to determine the significant differ-ence among the tested groups at p ≤ 0.05%. Results: Results showed that there were significant differ-ences of the values of the physical properties between the locally prepared dental stone with autoclave and the commercial one at p≤ 0.05 in specific gravity, water/ powder ratio and linear setting expansion. Conclusions :The results appeared the alpha- calcium sulfate hemihydrates dental stone that prepared in autoclave with adding crystal habit modifier has superior properties than of that prepared without modifier, but still not reach the properties of the commercial product. All values of the tested proper-ties were in accordance with ADA Specification

Abstract: Aims: The purposes of this study were to evaluate the efficacy of two rotary systems (RaCe and ProTaper) compared with hand files, in the removal of gutta percha during retreatment. Retreatment time, amount of apically extruded debris, and procedural errors were also evaluated. Materials and Methods: Forty extracted mandibular premolars were instrumented to size 30 and obturated with lat-eral condensed gutta percha. Then teeth were randomly divided into four groups, 10 teeth each. Re-moval was performing with chloroform and one of the following techniques: (I) Hedstrom and K-files, (II) Hedstrom and hand ProTaper, (III) Rotary ProTaper, and (IV) RaCe. Retreatment times, apically extruded debris, and broken instrument were recorded. The root split longitudinally viewed under ste-reomicroscope at (10 X) photograph are taken, and then the area of remaining filling material and whole area of the canal were measured using SigmaScan software. Data were analyzed statistically using one way ANOVA and Tukey test. Results: The two rotary systems left significantly less remain-ing filling material, faster, and produce less amount of apically extruded debris compared to hand files. There was no significant difference between the two rotary systems, but there was significant differ-ence between the two hand files regarding the amount of remaining filling materials. Only RaCe exhib-its no fracture instruments during retreatment. Conclusions: The two rotary systems were found to be effective and faster in removing gutta percha during endodontic retreatment.

Abstract: Aims: The aims of this research are to evaluate mandibular movements' normal values in a representativepopulation sample of various chronological ages, to analyze the differences according to thechronological ages groups, to find out the correlation between mandibular movements' values andheight and weight in each age group, and to determine gender differences in each age group. Materialsand Methods: A total of eight hundred forty subjects were chosen from primary and secondary schoolsand college of dentistry/Mosul University students and staff, in the city of Mosul in Iraq, and orderedinto six groups according to the chronological age. The variables analyzed were maximum mouthopening MO, right and left lateral RL and LL, and protrusion movements P; considering age, height,weight, and gender. Results: Mandibular movements' ranges and means in normal healthy Iraqi populationin the city of Mosul are: MO 35-70 mm 49.1 mm, RL and LL 4-13 mm 7.5 mm, P 3-13 mm 6.9mm. The maximum mandibular movements' values were in young adults group. There were significantpositive Pearson Correlations among mandibular movements' values, height, and weight. Significantdifferences P<0.5 were found in terms of gender and mandibular movements in all age groups, exceptthe children group. Conclusion: Mandibular movements' values were measured in order to establishnormal reference values in Mosulian Iraqi population. Age, height, weight, and gender are importantvariables in relation to mandibular movements' values.

Abstract: Aims: the aim of this in vitro study was to evaluate the apical sealing ability where the canals are pre-paid by two rotary NiTi systems . Materials and Methods: Thirty-six extracted human teeth with sin-gle root cut there crowns at the cemento-enamel junction CEG. The working length was determined for each tooth. The teeth were divided in to (3)groups ten of each . Group I the teeth were instrumented with ProTaper NiTi then the teeth obturated with matched-taper single cone. Group II of teeth were instrumented with RaCe NiTi rotary instrument and then obturated with matched-taper single cone. Group III were instrumented by hand instruments K-files and obturated by the lateral condensation techniques. Six teeth were divided as positive and negative control group three for each one . Tgadeseal was used as root canal sealer in this study. Adye penetration method was used to evaluate the apical seal using steromicroscope at 40X magnification. One-way analysis of variance and Duncan's test were used for statistical analysis. Results: The statistical analysis of the results demonstrated that there was no statistically significant difference in Microleakge between the two different rotary instrument each ProTaper and RaCe. While there was significant difference between the rotary instrument and the Hand instrument K-files. Conclusions: The use of the NiTi rotary instrument for root canal preparation showed the least apical microleakage, in compaired with hand instrument

Abstract: Aims: to evaluate the effect of implant length and diameter on the values and distribution of stresses of immediate loading implants by using three-dimensional (3D) finite elements (FE) analysis. Materials and Method: A 3-D FE model of an implant embedded in a block of bone was used in this study. The implant was LEADER/ ITALIA-Fix type which is specially designed for immediate loading. ANSYS V.12 program was used to build solid model of the implant and bone, and performing the finite element analysis. Two lengths of implant were used (11mm. and 13mm)., and two diameters (3.75mm. and 4.25mm.). Results: The results showed that the areas of maximum stress of all lengths and diameters are located at the neck of implants, the increase in the implant length from 11mm. to 13mm. leading to slightly increase in the stress at the implant-bone interface, while the increase in the diameter from 3.75mm. to 4.25mm. having no significant effect in increasing the value of stresses around dental im-plants. Conclusions: The increase in the implant length is negatively affect on stress values, but it leads to better dissipation of stresses around dental implant. The increase in the diameter having no obvious effect on stress values. However, it reduce the area of maximum stress at the implant neck

Abstract: Aims: To compare three maxillary nerve block techniques of local anesthesia in terms of success dur-ing minor oral surgical procedures on maxillary teeth. Materials and Methods: The clinical trial was conducted at the Department of Oral and Maxillofacial Surgery/ College of Dentistry/ Mosul Universi-ty. The subjects enrolled in the trial required surgical procedures on their upper anterior and / posterior teeth. The sample included 60 subjects who were divided into three groups of 20 each; Group I (control I) patients who were to receive the posterior superior alveolar nerve block technique. Group II (control II) patients who were to receive the infraorbital nerve block technique and Group III (control III) pa-tients who were to receive the maxillary nerve block technique of local anesthesia. For comparison, the following variables were recorded for the three techniques: Positive aspiration, onset of adequate surgi-cal anesthesia and pain grade scale during surgical procedure. Results: In regard to positive aspiration before injection of solution, the results showed no significant difference regarding positive aspiration among the three techniques. For onset of adequate surgical anesthesia, the results disclosed no signifi-cance difference in mean duration of onset of anesthesia among the three groups. In regard to pain ex-perienced during the surgical procedure , no significant difference was recorded among the three groups. Conclusions: The maxillary nerve block technique via the high tuberosity approach seems to be a safe and effective technique for achieving anesthesia of the hemimaxilla as long as there is strict adherence to the anatomical landmarks and approach described. The technique carries with it a high success rate and with specific applications can allow the dentist to provide painless dental treatment

Abstract: Aims: Aim of the study to evaluate the effect of two different disinfection methods for two periods of time on tensile strength and bond strength of soft denture lining materials (Vertex and Molloplast-B). Materials and methods : The effect of two disinfection methods ,first chemical disinfection method (which include artificial saliva , saturated salt and vinegar solution), and second microwave method on two physical properties the tensile and bond strength of soft denture lining materials for two periods of times (14 and 30 days) was evaluated, two hundred samples were prepared, one hundred samples to each property test . ANOVA and Duncan's multiple range test were performed to determine the signifi-cant difference among the tested groups at p ≤ 0.05% . Results: The result showed that the highest val-ue of tensile and bond strength of Vertex after 14 and 30 days were achieved with the microwave group, while for Molloplast -B highest value achieved with the control distilled water group. The low-est value was achieved after immersion in vinegar group for both soft lining material. A significant difference between the two soft lining materials among all disinfection methods at p≤ 0.05.Conclusions : The results appeared that the chemical disinfection and microwave disinfection methods have a significant effect on the tensile strength and bond strength of both vertex and Mol-loplast –B soft ling materials for two periods of time. Microwave disinfection has less effect than the chemical disinfection on the properties. The effect of disinfection increase significantly with increas-ing period of time .

Abstract: Aims: The aims were to evaluate mandibular residual ridge resorption for patients wearing lower com-plete dentures made of heat curing acrylic resin lined with acrylic soft liner and compare it with pa-tients wearing conventional heat curing dentures and compare patients satisfaction with dentures for both groups. Materials and Methods: Residual ridge resorption was evaluated in 35 male patients through a period of 6 months by means of digital panoramic radiographs, the patients divided into three groups, first group 5 patients not used prostheses, the second group 15 patients worn conventional heat curing dentures and the third group 15 patients worn dentures lined with acrylic based soft liner, the patients also surveyed about their satisfaction with dentures. Results: The results indicated insignifi-cant difference in the rate of residual ridge resorption between the three tested groups in 6 months peri-od. Conclusions: There is no significant difference between conventional heat curing dentures and dentures lined with acrylic based soft lining material regarding the rate of residual ridge resorption. Regarding denture satisfaction, most patients seem to have more comfortable denture and better chew-ing ability by using soft liners.

Abstract: Aims:This study carried out for histological assessment of the effect of local administration of estrogen hormone after mixing with collagen fiber of bovine bone on healing oftraumatic alveolar bone defect in the rabbits.Materials and Methods:Eight Rabbits were used, the vertical fissure was done in the man-dibular alveolar bone of the control group was filled with natural collagen fiber of bovinebone, while in the experimental group , this fissure was filled with estrogen hormone mixed with natural collagen fi-ber of bovine bone.Histological studies and statistical analysis were done.Results:The results showed that local administrations of estrogen hormone enhance new bone formation and new vascularization which is statistically significant when compare with control group.Conclusions: This study illustrate that the estrogen has an osteoinductive action to enhance bone healing process. Biostatistical analysis was shown significant relation; so bone healing enhanced by this material.

Abstract: Aims: This study aimed to evaluate the efficacy of some oral dentifrices in the reduction of cariogenic organism levels. Materials and Methods: The volunteers were divided into7 groups; 6 of them labeled with the type of dentifrice they use, plus one negative control. Saliva samples were collected at the baseline, after 2 and 4 weeks of dentifrice application to estimate mutans streptococci and lactobacillus levels. Results: Mutans streptococci level significantly declined after 2 weeks of zac, synsodyne, crest and signal use. In Sanino and amber group the elevated bacterial level remained throughout experi-mental period. The lactobacillus number increased in all groups except in zac there was a continuous decrease throughout the study. Conclusions: Synsodyne and crest toothpastes were the most effective among the tested dentifrices used to adjunct mutans streptococci count but lactobacillus was less af-fected. Only zac rinses were able to control the levels of the two bacterial types.

Abstract: Aims of the Study: To evaluate the efficacy of analgesia mediated by preoperative 100 mg IM Tra-madol to the post operative Tramadol and placebo after the surgical removal of mandibular wisdom tooth. Materials and Methods: Surgical removal of mandibular third molar was performed in three groups of individuals, total of thirty patients were anticipated in this study. All medically fit, average of age 24 + 2.2; each group consisted of ten patients. Group 1: Preoperative 100 mg Tramadol IM injec-tion 30 minutes prior surgical operation; Group 2: Post operative 100 mg Tramadol IM injection; Group 3: Placebo or control group where distilled water IM injection was applied. All patients received post operatively Augmentin capsules 675 mg tid, and supplementary Paracetamol 500 mg tablet as required. Analgesia was assessed by Visual Analog Scale (VAS) and Verbal Pain Scale (VPS), patient satisfaction (PS), duration of post operative analgesia and total number of analgesic tablet were record-ed between groups. Results: Analgesia mediated by Tramadol was superior in its efficacy compared to control group in both pre and post operative Tramadol groups, according to VAS and VPS assessment (p= 0.001). There was no significant difference between the preoperative and post operative analgesia according to VAS and VPS; whereas there was a significant difference in PS, and duration of analgesia mediated by the preoperative injection in comparison to the post operative and control groups. Conclu-sion: Preoperative Tramadol analgesia was superior to post operative analgesia in PS and prolonged duration of analgesia that explain its anti–nociceptive effect in controlling post surgical pain.

Abstract: Aims: The aim of this in vitro study was to evaluate the coronal seal of root canals prepared by two NiTi systems. Materials and Methods: Thirty-six extracted human teeth with single root canal were decoronated at the cemento-enamel junction (CEJ). The working length was determined for each tooth. Thirty teeth were divided into three groups ten of each. Group I teeth were prepared by Pro-Taper NiTi rotary instruments, then obturated by matched-taper single cone. Group II teeth were prepared by Ra-Ce NiTi rotary instruments and obturated also by matched-taper single cone. Group III teeth were pre-pared by hand K-files instrument then obturated by gutta percha lateral condensation technique. Re-maining teeth were used as control group, three positive and three negative control. Tgadeseal was used as root canal sealer for all groups in this study. Dye penetration method was used to evaluate the coro-nal seal using a steromicroscope at 40X magnification. All teeth (experimental group and control groups) were longitudinally sectioned for examination of dye penetration. One-way analysis of vari-ance and Duncan's tests was used for statistical analysis. There was significant differences between the groups (p< 0.05). Results: Statistical analysis of the results demonstrated that there was no statistical significant difference in coronal seal between the two systems. While, there was a significant differ-ence between the two rotary Ni-Ti systems and the hand K-files instrument. Conclusion: The use of Ni-Ti rotary instrument for root canal preparation shows least coronal microleakage in comparision with hand K-files instrument.

Abstract: Aims: To measure the linear shrinkage of composite resin by digital image analysis, to evaluate the effect of light curing type on composite resin linear shrinkage, to evaluate the effect of light curing intensity on linear shrinkage of composite resin and to evaluate the linear shrinkage of composite resin after 24 hours. Materials and method: images of composite samples were obtained before curing. The samples were cured with four types of light curing units, halogen light curing unit 420 mW/cm2, LED light curing unit 420 mW/cm2, halogen light curing 300 mW/cm2 and LED light curing unit 300 mW/cm2. the curing time was 40 seconds. After curing, the cured composite surface was exposed to the microscope allowing the attached camera to capture an image. The samples were then stored in 37 degree centigrade incubator for 24 hours and another image for each sample, was obtained. The images were analyzed via specially prepared image analysis program and the linear shrinkage was measured. Results: Regarding the type of LCUs, statistical analysis showed that composite samples cured with QTH LCUs exhibit significantly higher linear shrinkage values than those cured with LED LCUs. While regarding the intensity of the curing light, it was shown that LCUs with higher curing light in-tensities produce a significant higher values of linear shrinkage. Conclusion: The type and the intensity of the light curing unit play a major role in the end result linear shrinkage of the cured composite resin. Image analysis system is an excellent method to determine linear shrinkage.

Abstract: Aims: This study compared the reliability of measurements of soft tissue cephalometric analysis be-tween the direct digital and conventional cephalometric images using computerized cephalometric pro-gram and hand tracing. Materials and Methods: The adult sample consisted of (30) Iraqi subjects (females and males) with age ranged 18 – 25 years old, the samples satisfied the criteria of this study. Nine soft tissue measurements were recorded from lateral cephalometric radiographs using either hand tracing or digitally directly on the monitor. The data were analyzed using descriptive statistic and stu-dent’s t–test. Results: No significant differences were found between the conventional or hand tracing and digital cephalometric analysis. Conclusions: The analysis of soft tissue profile using digital cepha-lometric analysis is reliable as using the conventional method. Yet, the digital method had more benefit than the conventional method, such as reduction of the radiation dose and the image enhancement.

Abstract: Aims: To evaluate Streptococcus mutans adherence on bleached enamel surface with (7.5% hydrogen peroxide , 16% carbamide peroxide) with or without topical fluoride theraby. Materials and Meth-ods: Sixty specimens obtained from thirty maxillary premolars extracted for orthodontic reasons, cleaned, polished, and examined for any surface structural damage. The roots were discarded and crowns sectioned in two pieces (mesiodistaly) using diamond separating disc in low speed hand piece. The specimens randomly divided into six groups and exposed to one of the bleaching agents (7.5% hydrogen peroxide , 16% carbamide peroxide) with or without topical fluoride application. The nega-tive control group specimens stored in deionized water. The positive control group specimens stored in artificial saliva. Adherence of Streptococcus mutans count to enamel surfaces was determined bacte-riologically. The data analyzed statistically using one way ANOVA and Tukey test (p≤0.05). Results: there is significant increasing in Streptococcus mutans adherence on enamel surface after bleaching procedure, which was decreased significantly when used fluoride application technique after bleach-ing. Conclusions: Topical fluoride therapy has beneficial effect on reducing the Streptococcus mutans adherence on enamel surface after bleaching regimens which attributed in reducing the possibility of dental caries

Abstract: Aims: To determine the possible effect of genetic factor on Bolton tooth size discrepancy between sib-lings in families living in Mosul City (Iraq). Material and methods: The study sample included 126 subjects distributed between 45 families in Mosul City (Iraq), (56 females and 70 males) whose ages ranged between (20– 35) years. The sibling pairs were divided into three groups according to gender: male –male (24 pairs), female–female (18pairs), male–female (21 pairs). Electronic digital vernire with fine tips was used to measure the maximum mesio–distal widths of the teeth, and Bolton anterior and over all ratios was calculated. The effect of Heritability on Bolton ratios was studied by means of Har-vey’s mixed model least–squares and maximum likelihood computer program (LSMLMW) model type II. Results: Statistical analysis showed that Heritability was effective on Bolton tooth–size discrepancy in all groups, with the higher means for the anterior and over all ratios are for the male– male group. While the female–male group showed the lowest mean for the anterior ratio and the female –female group showed the lowest mean for the overall ratio. Conclusions: Siblings showed similar malocclu-sions, and examination of older sibling can provide clues to the need for interception and early treat-ment of malocclusion.

Abstract: Aims: To evaluated the effect of the repeated microwave disinfection on hardness of vertex denture lining material cured by water bath and microwave. Materials and Methods: Twenty specimens were prepared 4.5 mm thickness × 25 mm in diameter from denture lining material (Vertex , Holland) ad-hered to specimen 2.5 mm thickness × 50 mm in diameter form a heat-cured acrylic resin (Vertex, Holland) and divided into two main groups according to the curing method (waterbath and microwave). The specimens were divided as following, ten specimens, five for each curing method as a control group. The other ten, five specimens for each curing method for microwave disinfection, specimens immersed in 200 ml of distilled water and irradiated with 540 Watt per 3 minute, three times weekly for one month started from the first time of microwave irradiation (microwave disinfection) to twelve times, tested for hardness by using Shore –A- hardness durometer. Results: The independent t-test revealed that, significant differences between control groups (specimens cured by water bath higher than that cured by microwave method), and significant differences between first time of disinfection by domestic microwave oven cured by two methods. The analysis of variance (ANOVA) and Duncan multiple range test confirmed there is a significant difference in hardness of denture lining material in different times of disinfection by domestic microwave oven for both curing methods at significant level (P≤ 0.01). Conclusion: The repeated disinfection by microwave irradiation deteriorated the vertex den-ture lining material regardless to the curing methods.

Abstract: Aims: The present study aimed to investigate the desirable loading time of micro-screw implant by stability evaluation and detecting the possibility of using alendronate sodium to increase the stability. Materials and methods: Forty eight micro-screw implant, twelve adult rabbits and fourteen alendro-nate sodium ampoules were used in this study, the rabbits were divided into two main groups, treated and control group, which further subdivided into three subgroups. Eight micro-screw implant instilled in tibiaes of each subgroup just six of them used for test the remaining cancelled, the stability test down using the periotest. These subgroups were nominated according to the loading times which are immedi-ate loading, loading after two weeks and loading after four weeks with stability measured after instilla-tion, before and after loading and two weeks after loading. Results: No significant differences between subgroups before loading and after two weeks of loading but significant after loading. For immediately loaded treated subgroup no significant differences between immediate loading and two weeks after loading. For two and four weeks treated subgroup a significant difference in stability between immedi-ate instillation and after loading. Conclusions: Micro-screw implant even smaller diameter could be used as a fixed anchorage in orthodontics and possibly could be loaded safely from time of immediate instillation, further the use of alendronate sodium add no benefit to increase stability according to the criteria used in this study.

Abstract: Aims: to detect the prevalence of PTID among our Class II sample and to establish a simple method to assess it, providing a diagnostic and therapeutic guidance for the Class II malocclusion treatment. Ma-terials and methodes: The existence of (PTID) was investigated among 114 Class II div.I adults. Ran-domly selected 30 subjects from each group, adding 30 Class I subjects (as a control group) for cast and Cephalometric measurements. Resultes: Mandibular retrusion with posteriorly displaced mandible of normal size, was of functional mandibular retrusion, while this retrusion when caused by micrognathic mandible, was of anatomic mandibular retrusion. Conclusions: The relevance of these findings was stressed for the treatment planning of Class II subjects, confirming that controlling the transverse com-ponent of the occlusal patterns represent an additional input signal for the anteroposterior adjustment between the skeletal bases

Abstract: Aims: To evaluate weather micro-screw implants remain stationary or move against orthodontic forces during different healing periods (immediate loading, loading after 2 weeks and 4 weeks). Materials and Methods: Thirty micro-screw implants were implanted in 6 rabbits. These rabbits divided into 3 groups (2 in each group). The first group received loading immediaty after implantation. The second and third groups received loading after 2 weeks and 4 weeks of healing period respectively. The stabil-ity of these implants was measured using periotest device before and after loading. The data was ana-lyzed using descriptive statistic, Analysis of variance (ANOVA), Duncan Multiple analysis range test and student t-test. Result: Among the three groups, the first group having a significant greater stability of micro-screw implants immediately before and after loading and after 2 weeks of loading period. Conclusion: micro-screw implants can be loaded immediately after implantation with light orthodontic force; also these implants can be loaded after 4 weeks of healing period.

Abstract: Aims: To evaluate the effect of chlorhexidine digluconate rinsing solution on plaque and gingival bleeding in orthodontic patients with fixed appliances. Materials and Methods: This study included 42 orthodontic patients (29 females and 13 males), who were undergoing treatment in orthodontic postgraduate clinic of the collage of Dentistry, Mosul University. The patients of this study had a mean age of 18 years (range 12–28 years). The patients were divided in to control group (brushing only, N=20) and an experimental group (brushing +chlorhexidine digluconate mouth rinse, N=22). Plaque, gingival indices scores, in addition to pocket depth were measured in different three time periods (day 0, two weeks and four weeks). Results: Plaque, gingival indices scores, in addition to pocket depth shows statically significant differences at level (p≤0.05) among different genders between the two groups for each of the three time periods. Conclusions: The use of chlorhexidine digluconate based mouth rinses reduced bacterial plaque accumulation, pocket depth and improved the gingival index

Abstract: Aims: The study aims to evaluate the effect of mixing techniques and water powder ratio on the compres-sive strength and surface hardness of dental stone. Materials and Methods: The samples of compressive strength and surface hardness testes were prepared by 2 water powder ratio the ratio recommended by manufacture and that used by dentists and 2 mixing methods rubber bowl and spatula and zip-lock bag. The collected data analyzed using one sample t-test, ANOVA and Duncans' multiple range test at p≥0.5. Re-sults: The results showed statistically significant difference in compressive strength and surface hardness among tested groups. Conclusion: Mixing by rubber bowl and spatula and using water powder ratio rec-ommended by manufacturer gives the highest compressive strength value while using zip-lock bag give a higher surface hardness value than rubber bowl and spatula.

Abstract: Aims: The objective of this study is to determine (1) the effect of different resin-removal methods on tensile bond strength (TBS) of rebonded new brackets (2) compare various methods of enamel resin-removal to define the best method that produces adequate bond strength (3) to compare the bond strength of newly bonded enamel (virgin enamel) with previously bonded enamel after resin removal from the enamel surface with different methods. Materials and Methods: Seventy human premolars were bonded with stainless steel new brackets, then the teeth were randomly assigned in to 7 groups, each group of 10 teeth. Group1 (control group) where TBS at the first debonding was evaluated (initial bond). Group2 brackets were debonded by bracket removal plier and the remnant adhesive removed by high-speed tungsten carbide bur (TCB) and rebonded with brackets as in initial bond, then the TBS were tested. Group3 as with group2 except that the remaining resin were removed by low-speed TCB . Group 4 as with group2 except that the remaining resin were removed by Diamond carbide Disk . Group 5 as with group2 except that the remaining resin were removed by a microetcher, Group 6 as with group 2 except that the remaining resin were removed manually by composite removing pliers, Group 7 as with group6 except that rebonding bracket without cleaning enamel with rubber cup and pumice. Results: All rotary instrument groups (G2, G3 and G4) showed significant increase in the TBS in comparing with the other groups (G1, G5, G6 and G7) also there were significant decrease in the TBS of the manually removal of adhesive remnant groups in comparing with control group, while there were no significant differences between microetcher group and control group with greater mean value for control group. Conclusions: The outcomes of this study showed that the use of the rotary instrument in the removal of adhesive remnant gives the highest tensile bond strength in compared with the other methods used in this study .