Bayram Çörekçi

Cytotoxic effects of orthodontic composites

OBJECTIVES To evaluate the cytotoxic effects of five different light-cured orthodontic bonding composites. MATERIALS AND METHODS The orthodontic composites Heliosit Orthodontic (Ivoclar), Transbond XT (3M Unitek), Bisco ORTHO (Bisco), Light Bond (Reliance), and Quick Cure (Reliance) were prepared, and the samples were extracted in 3 mL of BME (Basal Medium Eagle) with 10% newborn calf serum for 24 hours. The L929 cells were plated (25,000 cells/mL) in a 96-well dish and maintained in a humidified incubator for 24 hours at 37 degrees C, 5% CO(2), and 95% air. After 24 hours of incubation of the cells, the incubation medium was replaced by the immersed medium in which the samples were stored. Then, L929 cells were incubated in contact with eluates for 24 hours. The cell mitochondrial activity was evaluated by the methyl tetrazolium (MTT) test. Twelve wells were used for each specimen, and the MTT tests were applied two times. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Tukey HSD tests. RESULTS Results with L929 fibroblasts demonstrated that except for Transbond XT, freshly prepared composite materials did not reduce vital cell numbers (P > .05) compared with the control group. Our data demonstrate that Transbond XT showed significant cytotoxicity compared with the control group. CONCLUSION Results indicate that tested orthodontic bonding composites are suitable for clinical application, but that further studies using different test methods are needed for Transbond XT.

Real-time cell analysis of the cytotoxicity of orthodontic mini-implants on human gingival fibroblasts and mouse osteoblasts

INTRODUCTION The aim of this study was to evaluate the cytotoxic effects of orthodontic mini-implants on gingival fibroblasts and osteoblasts. METHODS The orthodontic mini-implants used in this study were Orthodontic Mini Implant (Leone, Florence, Italy), MTN (MTN, Istanbul, Turkey), AbsoAnchor (Dentos, Daegu, South Korea), IMTEC Ortho (3M Unitek, IMTEC, Ardmore, Okla), VectorTAS (Ormco, Glendora, Calif). The materials were incubated in Dulbeccos modified eagles culture medium for 72 hours according to ISO 10993-5 standards (surface area-to-volume ratio of the specimen to cell-culture medium, 3 cm(2)/mL). A real-time cell analyzer (xCELLigence, Roche Applied Science, Mannheim, Germany; ACEA Biosciences, San Diego, Calif) was used to evaluate cell survival. After seeding 200 μL of the cell suspensions into the wells of the E-plate 96, gingival fibroblasts were treated with bioactive components released by the metallic materials and monitored every 15 minutes for 190 hours. For the proliferation experiments, the statistical analyses used were 1-way analysis of variance and Tukey-Kramer multiple comparisons tests. RESULTS There was no significant differences between the human gingival fibroblast cell indexes of the control and study groups (P >0.05). When evaluated at 27 and 96 hours, only the VectorTAS mini-implants showed statistically significant decreases in the M3T3 cell index (P <0.001) compared with the control group. No significant differences were found among the control and all study groups (P >0.05). Furthermore, the Leone and MTN mini-implants showed statistically significant decreases (P <0.001) at 190 hours. Also, the VectorTAS mini-implants demonstrated a significant decline (P <0.05) at the same time in the M3T3 cell index. CONCLUSIONS These findings provide fundamental knowledge and new insights for future design and development of new biocompatible titanium alloys for orthodontic mini-implants and temporary anchorage devices.

Effects of staining solutions on the discoloration of orthodontic adhesives: An in-vitro study

INTRODUCTION Our aim was to evaluate the effects of staining solutions on the discoloration of orthodontic adhesives. METHODS Six orthodontic adhesives were investigated (Transbond XT [3M Unitek, Monrovia, Calif, USA], Heliosit Orthodontic [Ivoclar Vivadent, Liectenstein], Light Bond [Reliance Orthodontic Products, Itasca, IL, USA], Bisco Ortho [Bisco, Schamburg, IL, USA], Quick Cure [Reliance Orthodontic Products, Itasca, IL, USA], and Filtek Supreme XT [3M ESPE, St Paul, Minn, USA]), and 5 beverages (tea, cola, coffee, red wine, and yogurt). Sixty specimens were prepared. Five specimens from each group were stored in each of the 5 staining solutions. The 5 remaining specimens from each group served as the controls and were stored in distilled water. The specimens were immersed in staining solutions and water at 37°C ± 1°C for 5 days. The test period was 25 days. Before and after the test period, color measurements were carried out with a spectrophotometer, and color changes (ΔE∗) were calculated. Statistical differences were evaluated by using analysis of variance (ANOVA) and the Tukey HSD tests. RESULTS Adhesive materials, staining agents, and their interactions were found to play statistically significant roles (P < 0.001) in color changes. Among the adhesive materials, the Light Bond water control group consistently showed the lowest ΔE∗ value for all materials, and the Filtek Supreme XT group showed the highest ΔE∗ value for all materials. After the in-vitro experimental process for staining solutions and water, unsatisfactory color stability was observed for the conventional adhesive systems except for Light Bond, Transbond XT, and Bisco Ortho water control group (ΔE∗ > 3.7), respectively. CONCLUSIONS In esthetically critical areas, discoloration of adhesive materials for fixed orthodontics can cause patient dissatisfaction. Orthodontic composites will discolor from staining beverages during their lifespan.

Cytotoxic effects of resin-modified orthodontic band adhesives. Are they safe?

OBJECTIVE To evaluate the cytotoxic effects of three different resin-modified orthodontic band adhesives. MATERIALS AND METHODS Three resin-modified orthodontic band adhesives (Bisco Ortho Band Paste LC, Multi-Cure Glass Ionomer Band Cement, and Transbond Plus Light Cure Band Adhesive) were prepared and the samples were extracted in 3 mL of Basal Medium Eagle with 10% newborn calf serum for 24 hours. The L929 cells were plated (25,000 cells/mL) in wells of 96-well dishes and maintained in a humidified incubator for 24 hours at 37 degrees C, 5% CO(2), and 95% air. After 24-hour incubation of the cells, the incubation medium was replaced by the immersed medium in which the samples were stored. Then L929 cells were incubated in contact with eluates for 24 hours. The cell mitochondrial activity was evaluated by the methyltetrazolium test. Twelve wells were used for each specimen, and methyltetrazolium tests were applied two times. The data were statistically analyzed using one-way analysis of variance and Tukey Honestly Significantly Different tests. RESULTS Results with L929 fibroblasts demonstrated that all freshly prepared resin-modified orthodontic band adhesive materials reduced vital cell numbers (P > .05), in comparison to the control group. Our data demonstrate that all materials showed significant cytotoxicity compared to the control group. CONCLUSIONS The results indicate that all materials showed significant cytotoxicity compared to the control group, and further studies using different test methods are needed for all resin-modified orthodontic band adhesives.

Dentofacial changes from fan-type rapid maxillary expansion vs traditional rapid maxillary expansion in early mixed dentition

OBJECTIVE To test the null hypothesis that there is no difference between the effects of fan-type rapid (FRME) and rapid maxillary expansion (RME) used with an acrylic bonded expansion appliance on dentofacial structures in early occlusal stages. MATERIALS AND METHODS This was a prospective clinical trial. The FRME group had an anterior constricted maxillary width with a normal intermolar width, and the RME group had bilateral constricted maxillary width. The FRME group consisted of 20 patients (mean age, 8.96 ± 1.19 years), and the RME group consisted of 22 patients (mean age, 8.69 ± 0.66 years). Lateral and frontal cephalometric radiographs and dental casts were taken before and after expansion and 3 months after completing treatment for each patient. The data were compared using repeated-measures analysis of variance. The paired-samples t-test was used to evaluate treatment and retention effects, and the independent samples t-test was used to consider the differences between the two groups. RESULTS The maxilla moved downward and forward in both groups. The nasal cavity and maxillary width were expanded more in the RME group, and there were only a few relapses in this group during the retention period. There was significant labial tipping of the upper incisors in the FRME expansion group. The expansion of intercanine width was similar in both groups, but the expansion of intermolar width was significantly greater in the RME group. CONCLUSION The null hypothesis was rejected. There was a difference between the effects of FRME and RME used with an acrylic bonded expansion appliance on dentofacial structures in the early occlusal stages.

Bond strength of aged lingual retainers

Introduction: The purpose of this study was to examine the tensile bond strength (TBS) of two different lingual retainer (LR) composite systems and three LR wires after they were aged by loadcycling and thermocycling. Materials and Methods: A 15 mm length of wire was bonded to the lingual surfaces of pairs of human incisors using two bonding techniques. Seventy-two pairs of incisors were placed into six groups, and loadcycling (50,000 times) and thermocycling (10,000 times) were performed. The failure characteristics examined included the maximum force for debonding and the site of failure. The adhesive remnant index scores were calculated. Data were compared by two-way analysis of variance and Tukey highly significant difference analysis. Results: All groups generally showed statistically significant differences in TBS score (P < 0.05). For each group, the highest average TBS score (P < 0.05) was obtained from a Transbond LR + Remalloy LR combination. The main failure type was a mixed failure. Conclusions: Retainer wire and composite combinations had significant differences. One of the best selection criteria for LRs is the determination of the bond strength needs of a case.

Does stinging nettle (Urtica dioica) have an effect on bone formation in the expanded inter-premaxillary suture?

OBJECTIVE To determine whether systemically given stinging nettle (SN) has an effect on bone formation in response to expansion of the rat inter-premaxillary suture. MATERIALS AND METHODS A total of 28 male Wistar albino rats were randomly divided into 4 equal groups: control (C), only expansion (OE), SN extract given only during the expansion and retention periods (SN group; a total of 17days), and SN extract given during the nursery phase before expansion (a period of 40days) and during the expansion and retention periods (N+SN group; a total of 57days). After the 5-day expansion period was completed, the rats in the OE, SN, and N+SN groups underwent 12days of mechanical retention, after which they were sacrificed, and their premaxilla were dissected and fixed. A histologic evaluation was done to determine the number of osteoblasts, osteoclasts, and capillaries, as well as the number and intensity of inflammatory cells and new bone formation. RESULTS Statistically significant differences were found between the groups in all histologic parameters except the ratio of intensities of inflammatory cells. New bone formation and the number of capillaries were significantly higher in the SN groups than in the other groups. The statistical analysis also showed that the numbers of osteoblasts, osteoclasts, and capillaries were highest in the N+SN group. CONCLUSION Systemic administration of SN may be effective in accelerating new bone formation and reducing inflammation in the maxillary expansion procedure. It may also be beneficial in preventing relapse after the expansion procedure.

Effect of Royal Jelly on new bone formation in rapid maxillary expansion in rats

Background The aim of this study was to evaluate the effects of long and short term systemic usage of royal jelly on bone formation in the expanded maxillary suture in a rat model. Material and Methods Twenty eight Wistar albino rats were randomly divided into 4 equal groups: Control (C); Only Expansion (OE), Royal Jelly (RJ) group, Royal Jelly was given to rats by oral gavage only during the expansion and retention period; Royal Jelly plus Nursery (RJN) group, Royal Jelly was given to rats by oral gavage during their nursery phase of 40 days and during the retention period. After the 5 day expansion period was completed, the rats underwent 12 days of mechanical retention. All rats were sacrificed in same time. Histological examination was performed to determine the number of osteoclasts, number of osteoblasts, number of capillaries, inflammatory cell infiltration, and new bone formation. Results New bone formation, number of osteoclasts, number of osteoblasts, and the number of capillaries in the expanded maxillary sutures were higher in the RJ and RJN groups than in the other groups. Statistical analysis also demonstrated that new bone formation and the number of osteoblasts was also highest in the RJN group. Conclusions The systemic administration of Royal Jelly in conjunction with rapid maxillary expansion may increase the quality of regenerated bone. Key words:Bone formation, rapid maxillary expansion, Royal jelly.

Effects of plasma-emulating light emitting diode (LED) versus conventional LED on cytotoxic effects of orthodontic cements as a function of polymerization capacity.

Objectives: The study was aimed at evaluating, in vitro, cytotoxicity of four resin-based orthodontic cements (RBOC) as a function of degree of conversion (DC) and the light curing unit (LCU) employed on mouse fibroblast (L929). Materials and Methods: Nine samples were manufactured for each group of cements using plasma-emulating light-emitting diode (LED) and conventional LED. Toxicity was assessed by immersing four specimens to culture medium (24 h/37°C) for extracting residual monomer or cytotoxic substance. Cell mitochondrial activity of L929 cell was evaluated using methyl tetrazolium (MTT) test. DC was evaluated by Fourier transform infrared spectroscopy for five samples. Results: Cements, LCUs, and interaction between cements and LCUs were found to play a statistically significant role in cytotoxicity (p < 0.0001). Opal band cement (OPAL) plasma LED was found noncytotoxic (90–100% cell viability). The other RBOC–LCU combinations were slightly cytotoxic (60–90% cell viability). Cements (p < 0.01) and LCUs (p < 0.05) had a statistically significant effect on DC. Conversely, interaction between cement and LCU had no statistically significant role on DC (p > 0.05). OPAL plasma LED displayed the highest levels of DC. The correlations between cell viability and DC were positive for three RBOCs. Conclusion: Therefore, high-intensity LCUs can be said to efficiently affect polymerization, so higher DC rates may achieve higher cell viability rates. Clinical Relevance: Cements and LCUs must be matched to each another to result in higher DC and maximal biocompatibility. Dual cure systems presented relatively high cell survival and higher DC, thus expressing superior to single-cure systems with plasma LED.

Effects of plasma-emulating light-emitting diode (LED) versus conventional LED on cytotoxic effects and polymerization capacity of orthodontic composites

Objectives: The aim of this study was to evaluate, the cytotoxicity of orthodontic composites in vitro as a function of degree of conversion (DC) and the light curing units (LCU) employed on mouse fibroblast (L929). Materials and Methods: Cured samples of the composites Light bond (Reliance Orthodontic Products, Itasca, Illinois, USA), Ortho bracket paste (Bisco, Schaumburg, Illinois, USA), Opal bond MV (OPAL, South Jordan, Utah, USA), and Transbond XT (3M, Monrovia, California, USA) were prepared. Polymerization was performed with two LCUs: VALO Ortho (Ultradent, South Jordan, Utah, USA) is a third-generation LCU and Elipar S10 (3M, USA) is a second-generation LCU. Four samples were immersed in cell culture medium to obtain composite extracts. After incubation of L929 cell cultures with the extracts obtained, cytotoxicity was determined using the methyl tetrazolium test. Fourier transform infrared spectroscopy (FTIR) was used to evaluate DC for five samples. A multivariate analysis of variance (ANOVA), two-way ANOVA, and Tukey’s honestly significant difference test were utilized for statistical analyses. Results: Cytotoxicity and DC of all tested composites (p < 0.001) and the interaction between composites and LCUs (p < 0.01) were significantly different. LCUs had no significant influence on the cytotoxicity and DC of composite materials (p > 0.05). The correlations between cell viability and DC were positive for three composites but statistically insignificant. Conclusion: Composites and LCUs must be matched with one another to result in satisfactory maximal biocompatibility and DC. Opal Bond plasma light-emitting diode combination was a better choice for cell viability. Three composites showed a positive correlation between cytotoxicity and DC. Therefore high-intensity LCUs can be said to efficiently affect polymerization, and so, higher DC rates may achieve higher cell viability rates.