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Öğe Biomechanical evaluation of mandibular midline distraction osteogenesis by using the finite element method(MOSBY-ELSEVIER, 2004) Basciftci, FA; Korkmaz, HS; Iseri, H; Malkoc, SThe aim of this study was to evaluate the biomechanical effects of mandibular midline distraction osteogenesis on the mandibular complex by using a 3-dimensional finite element model, whose construction was based on computer tomography scans of the mandible of a 22-year-old man. The computer tomography pictures were transferred and converted to the finite element model by means of a procedure developed for this study. The final mesh consisted of 1314 solid elements with 3076 nodes. The distraction was performed on the middle intersection point of the vertical and horizontal planes on the mandibular symphysis. The mechanical response in terms of displacement and von Mises stresses was determined by widening the mandible up to 5 mm on both sides. The results indicate that the mandible was separated almost in a parallel manner (4.45-5.0 mm separation from the mandibular incisors to the lower border of the mandibular symphysis and 4.09-4.92 mm from the mandibular canines to the symphyseal border at the canine region), superoanteriorly. Anteroposterior evaluation demonstrated that the greatest widening was achieved at the symphyseal region, and the widening effect gradually decreased from anterior to posterior. Viewed occlusally, the width of the mandibular bone at the symphyseal region increased remarkably, whereas the ramal and gonial regions of the mandible and the condyle had shown minimal displacement. Mandibular bone was displaced forward and slightly downward. The highest stress levels were observed bilaterally below the condylar areas. High stress levels were also observed in the ramal region of the mandible.Öğe Comparison of two different gingivectomy techniques for gingival cleft treatment(E H ANGLE EDUCATION RESEARCH FOUNDATION, INC, 2004) Malkoc, S; Buyukyilmaz, T; Gelgor, I; Gursel, MInterdental clefts or invaginations contribute to orthodontic relapse and poor periodontal health in extraction cases. These clefts or invaginations can be removed both by electrosurgical or conventional surgical gingivectomy techniques. This study investigates and compares the efficacy of two different techniques to remove gingival clefts with respect to periodontal health and patient tolerance. Twenty-two patients (mean age, 15.7 years) with bilateral gingival clefts participated in this study. In each patient, the gingival invaginations were removed by gingivectomy using electrosurgery on one side and conventional surgery on the contralateral side. The length and depth of the invaginations, the gingival index of the adjacent teeth, and the changes in visual analogue scale scores were recorded before and after the operation for both groups. Mann-Whitney U-test and Wilcoxon tests were used to analyze the data statistically. The results showed significant improvement in invagination depth and length and gingival index scores for both techniques. There were no statistical differences between the two gingivectomy techniques with respect to gingival health and patient tolerance. Both techniques can be used to remove the gingival invaginations efficiently.Öğe The effect of head rotation on cephalometric radiographs(OXFORD UNIV PRESS, 2005) Malkoc, S; Sari, Z; Usumez, S; Koyuturk, AE[Abstract not Available]Öğe The effect on shear bond strength of different antimicrobial agents after acid etching(OXFORD UNIV PRESS, 2005) Malkoc, S; Demir, A; Sengun, A; Ozer, FThe aim of the present study was to determine whether the application of different primers containing antibacterial agents (Micro Prime (TM), Seal&Protect (TM), and Gluma Desensitizer (TM)) can affect the shear bond strength (SBS) of an orthodontic resin composite. Seventy-two crowns of extracted lower human incisors were mounted in acrylic resin leaving the buccal surface of the crowns parallel to the base of the moulds. The teeth were randomly distributed into three experimental and one control group, each containing 18 teeth. In each experimental group, the primers were applied to the etched enamel surfaces. In the control group, no antibacterial primer was used. An orthodontic composite resin was applied to the surface into cylindrical-shaped plastic matrices after application of an orthodontic adhesive primer (Transbond XT). For shear bond testing, a stubby-shaped force transducer apparatus (Ultradent) was applied at a crosshead speed of 1 mm/minute to each specimen at the interface between the tooth and the composite until failure occurred. A Kruskal-Wallis one-way ANOVA and a Mann-Whitney U-test with a Bonferroni adjustment were used for statistical analysis. There was no significant difference between Seal&Protect (TM) (27.98 +/- 8.73 MPa) and the control (35.15 +/- 7.85 MPa) (P > 0.05). However, Gluma (TM) (21.61 +/- 7.96 MPa) and Micro Prime (TM) (14.89 +/- 5.55 MPa) caused a decrease in bond strength (P < 0.05). No statistically significant difference was observed between Seal&Protect (TM) and Gluma (TM) (P > 0.05). As triclosan containing Seal&Protect (TM) did not cause a significant decrease in bond strength, it can potentially be used under an orthodontic resin composite to obtain an antibacterial effect. However, further in vivo studies are required.Öğe Effects of chlorhexidine and povidone-iodine mouth rinses on the bond strength of an orthodontic composite(E H ANGLE EDUCATION RESEARCH FOUNDATION, INC, 2005) Demir, A; Malkoc, S; Sengun, A; Koyuturk, AE; Sener, YThe purpose of this study was to determine whether the application of two antibacterial mouth rinses to etched and unetched enamel affects the shear bond strength (SBS) of an orthodontic composite resin. Eighty-five lower human incisors were divided into five groups, ie, group 1: control group, no mouth rinse was used; groups 2 and 3: mouth rinses were applied to the intact enamel surface before etching; groups 4 and 5: mouth rinses were applied to the etched enamel. A bonding agent and a composite resin were applied to the teeth surface. For shear bond testing, the specimens were mounted in a universal testing machine, and an apparatus attached to a compression load cell was applied to each specimen until failure occurred. The data were analyzed using analysis of variance and Tukey honestly significance tests. Fracture modes were analyzed by Mann-Whitney U-test. There was no statistically significant difference between the SBS values of group 1 (31.64 +/-- 3.62 MPa) and group 4-five experimental applications (P >= .05). However, the SBS value of group 3 (36.56 +/- 5.95 MPa) was significantly larger than those of group 4 (30.00 +/- 4.97 MPa) and group 5 (30.26 +/- 7.30 MPa). In addition, no significant differences were observed between group 1 and groups 2 (34.33 +/- 7.26 MPa) and 3 (36.56 +/- 5.95 MPa) (P >= .05). Because the application of chlorhexidine and povidone-iodine before acid etching did not cause any decrease in bond strength, it is advisable for use under the orthodontic resin composite to obtain an antibacterial effect or to prevent the risk of bacteremia.Öğe Evaluation of the dental plaque pH recovery effect of a xylitol lozenge on patients with fixed orthodontic appliances(E H ANGLE EDUCATION RESEARCH FOUNDATION, INC, 2004) Sengun, A; Sari, Z; Ramoglu, SI; Malkoc, S; Duran, IThe purpose of this study was to evaluate the influence of a xylitol lozenge on the dental plaque pH profile of fixed orthodontic patients. Twelve volunteers participated in this study. Before the measurement of plaque pH, subjects were asked to refrain from brushing their teeth for 48 hours and from eating and drinking for two hours. The subjects' baseline dental plaque pH was recorded using the touch technique. It was followed by a one-minute rinse with 15 ml of a 10% solution of sucrose, and subsequent plaque pH measurements were carried out during the next one hour. Xylitol lozenges were taken five times a day during a 14-day period. The variables of resting-plaque pH, minimum-plaque pH (MP pH), time required to reach MP pH (TMP), last-plaque (LP) pH at the end of one hour, cH area (CH), and pH at each test time were calculated for each pH test of the subjects. The paired sample t-test was used for statistical comparison. The mean MP pH values increased from 4.81 to 5.09 in the experimental measurement (P < .05). The mean TMP was not affected by the use of xylitol (P > .05). Although the LP pH showed an increase during the experimental period, the difference between control and experimental periods was not statistically significant (P > .05). The CH of the experimental period was significantly less than that of the control period (P < .05). As a result, the use of a xylitol lozenge after a sucrose challenge can be an advisable practice for fixed orthodontic patients to prevent future dental caries.Öğe Long-term skeletal effects of mandibular symphyseal distraction osteogenesis. An implant study(OXFORD UNIV PRESS, 2005) Iseri, H; Malkoc, SThe purpose of this study was to investigate the long-term skeletal effects of mandibular symphyseal distraction osteogenesis (MSDO) with a tooth- and bone-borne distraction device, analysed using the metallic implant method. The study sample comprised 20 patients between 15.8 and 25 years of age, with a mean age of 20.01 +/- 2.25 years at the start of treatment. In 12 subjects, titanium implants were inserted in the mandible to analyse mandibular skeletal changes in the short and long term. A custom-made intraoral, tooth- and bone-borne distractor was designed and used. After a latency period of 7 days, the distractor was activated twice daily, by a total amount of 1 mm. Postero-anterior (PA) cephalograms were obtained at the start of distraction and at the end of consolidation (94.95 +/- 5.79 days after surgery) and follow-up periods (21.5 +/- 4.6 months after consolidation). The data were analysed statistically using paired t-tests. The mean amount of screw activation was 8.10 +/- 1.68 mm. The inter-symphyseal and inter-molar implant distances and the bimolar width significantly increased during the consolidation period (P < 0.001) and were maintained at the end of the follow-up. On the other hand, the bicondylar width was markedly decreased (P < 0.05), while no significant skeletal changes were observed in bigonion and biantigonion widths, inter-ramal implant distance, or inter-ramal and implant angles at the end of the consolidation period. The long-term findings of this study indicate that MSDO provides an efficient and stable non-extraction treatment alternative, mainly by increasing the anterior mandibular skeletal and dental arches.Öğe Microscopic evaluation of mandibular symphyseal distraction osteogenesis(E H ANGLE EDUCATION RESEARCH FOUNDATION, INC, 2006) Duran, I; Malkoc, S; Iseri, H; Tunali, M; Tosun, M; Kucukkolbasi, HThe purpose of this study was to evaluate microscopically the newly formed hard tissue after a consolidation period of mandibular symphyseal distraction osteogenesis (MSDO). Sixteen patients underwent MSDO treatment. After a latency period of seven days, the distraction device was activated by the patient once in the morning and once in the evening, for a total of one mm per day for a mean 10.1 +/- 2.8 days, and the mean opening of the device was 8.1 +/- 1.7 mm. The device was usually maintained in position approximately 90 days after surgery. After the completion of the distraction period, the lower anterior teeth were bonded and tooth movement into the distraction site was initiated. After a consolidation period, second surgery was performed to remove the distraction devices. During the second surgery, hard tissue biopsies were taken on the apical region of the two central incisors and the left canine. The samples were fixed in 10% buffered formalin and decalcified in 3% HNO3 solutions. New bone formation was present within the distraction gap immediately after the consolidation period. The cellular construction was more irregular in the distraction sections than in the normal bone sections. The newly distracted area was not complete immediately after the consolidation period. Furthermore, the newly formed bone had a membranous structure, which indicates continual maturation. Bone exposed to stretching forces undergoes new bone formation, and the newly formed bone is of a membranous type also named as a woven type.Öğe Reproducibility of airway dimensions and tongue and hyoid positions on lateral cephalograms(MOSBY-ELSEVIER, 2005) Malkoc, S; Usumez, S; Nur, M; Donaghy, CEIntroduction: The aim of this study was to evaluate the reproducibility of airway dimensions and tongue and hyoid positions on lateral cephalometric radiographs. Methods: Three lateral cephalograms each of 30 patients were obtained in natural head positions at 30-minute intervals. Twelve measurements, including pharyngeal airway dimensions and tongue and hyoid positions, were taken. The relationships between 3 sets of measurements were evaluated by using repeated analysis of variance, Dahlberg's method error formula, and correlation coefficient. Results: No statistically significant differences were found between the 3 sets of measurements with the repeated analysis of variance (P > .05). Correlation coefficient values ranged between 0.964 (vertical position of the hyoid) and 0.683 (hypopharyngeal airway width). The average method error was 1.22 mm. Conclusions: The results suggest that airway dimension and tongue- and hyoid-position measurements are highly reproducible on natural-head-position cephalograms.Öğe Submentovertex cephalometric norms in Turkish adults(MOSBY-ELSEVIER, 2005) Uysal, T; Malkoc, SThe aims of this study were (1) to establish cephalometric norms from submentovertex (SMV) radiographs for young Anatolian Turkish adults and (2) to identify possible sex differences between men and women. Methods: SMV cephalograms were taken of 50 nongrowing Turkish adults (25 men, mean age, 23.06 +/- 2.30 years; 25 women, mean age, 22.10 +/- 2.04 years). All had normal occlusions and well-balanced faces. Five angular and 10 linear measurements were made on each radiograph. For each variable, arithmetic mean and standard deviation minimum and maximum values were calculated. Independent-sample t tests were performed for the sex comparisons. Cephalometric angular and linear norms for Turkish adults were determined by using the Lew-Tay SMV cephalometric analysis. SMV cephalometric standards for Turkish adults were also developed. Results: Generally, our measurements were similar to the Lew-Tay SMV norms. Most Turkish SMV cephalometric measurements showed statistically significant sex differences. Comparison between Turkish men and women indicated larger measurements for men in all investigated linear measurements. Conclusions: SMV cephalometric norms are useful in the diagnosis of mandibular asymmetries and the treatment of dentofacial orthopedics in Turkish patients.
