Suat Ozcan

Effects of different topical agents on enamel demineralization around orthodontic brackets: an in vivo and in vitro study

BACKGROUND The aim of this study was to evaluate the in vivo and in vitro effects of a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride containing topical agents in reducing enamel demineralization around orthodontic brackets, and to compare this with a control group. METHODS Twenty-one patients and 60 extracted premolars were divided into three groups: two experimental and one control. Tooth Mousse® (CPP-ACP gel; GC-Corp, Tokyo, Japan) and Fluoridin N5® (Fluoride gel; Voco-GmbH, Cuxhaven, Germany) were applied to tooth surfaces around orthodontic brackets in the experimental groups. Teeth were extracted after 60 days to evaluate the in vivo effects of the testing materials. For the in vitro experiment, samples were cycled for 14 days through a daily procedure of demineralization. All teeth were sectioned and evaluated by superficial microhardness analysis. An indentation was made from two positions (occlusal-cervical) and one depth (10 μm). RESULTS Comparisons of occlusal and cervical microhardness scores for all specimens showed no statistically significant side differences. A multiple comparison test showed that the use of CPP-ACP and fluoride containing topical gels were more significantly efficient than the control group (p<0.001). No significant differences were detected between CPP-ACP and the fluoride groups against demineralization. CONCLUSIONS In vivo and in vitro evaluations indicated that CPP-ACP and fluoride containing agents successfully inhibited caries around orthodontic brackets.

Effect of antibacterial monomer-containing adhesive on enamel demineralization around orthodontic brackets: An in-vivo study

INTRODUCTION The aims of this study were to evaluate the effect of an antibacterial monomer-containing self-etching adhesive in reducing enamel demineralization around orthodontic brackets in vivo and to compare it with the conventional adhesive system quantitatively. METHODS Fourteen orthodontic patients were randomly divided into 2 equal groups; they received brackets fitted to all their teeth, bonded with either Clearfil Protect Bond (Kuraray Medical, Okayama, Japan) (experimental group) or Transbond XT (3M Unitek, Monrovia, Calif) (control group). Block randomization to obtain equal numbers in each group was used. After 30 days, all first premolars were extracted with orthodontic indications and longitudinally sectioned. Demineralization was assessed by cross-sectional microhardness. Determinations were made at the bracket edge cementing limits and at occlusal and cervical points 100 and 200 μm away from the edge. In all of these positions, 6 indentations were made at depths of 10 to 90 μm from the enamel surface. Analysis of variance (ANOVA) and the Tukey post-hoc test were used. The statistical significance level was set at P <0.05. RESULTS ANOVA showed statistically significant differences for adhesive type, position, depth, and their interactions (P <0.05). The multiple comparison test showed that the antibacterial monomer-containing adhesive was significantly more efficient than the conventional adhesive system, reducing enamel demineralization in almost all evaluations (P <0.05). CONCLUSIONS The results indicated that using antibacterial monomer-containing adhesive for bonding orthodontic brackets successfully inhibited caries in vivo. This cariostatic effect was localized at the area around the brackets and was significant after 30 days.

In vivo effects of amorphous calcium phosphate-containing orthodontic composite on enamel demineralization around orthodontic brackets

BACKGROUND The aim of this study was to evaluate the in vivo effects of an amorphous calcium phosphate-containing orthodontic composite in reducing enamel demineralization around orthodontic brackets, and to compare it with the control. METHODS Fourteen orthodontic patients were divided into two equal groups. They received brackets fitted to all first premolars, bonded with either Aegis Ortho® (The Bosworth Co.), an ACP-containing orthodontic composite (experimental group), or Concise® (3M Dental Products), a resin-based orthodontic composite (control group). After 30 days, the teeth were extracted and longitudinally sectioned, and evaluated by superficial-microhardness analysis. The determinations were made at the bracket edge cementing limits and at occlusal and cervical points 100 and 200 μm away from the edge. In all of these positions, indentations were made at depths of 10, 20, 30, 50, 70, and 90 μm from the enamel surface. Analysis of variance (ANOVA) and Tukey post hoc test was used. The statistical significance level was set at p<0.05. RESULTS The ANOVA showed statistically significant differences for position, material, depth, and their interactions (p<0.001). The multiple comparison test showed that the ACP-containing orthodontic composite was significantly more efficient than the control composite, reducing enamel demineralization in almost all evaluations (p<0.001). CONCLUSIONS Present results indicated that ACP-containing orthodontic composite for bonding orthodontic brackets successfully inhibited demineralization in vivo. This effect was localized to the area around the brackets and was statistically significant after 30 days.

Does a chitosan-containing dentifrice prevent demineralization around orthodontic brackets?

OBJECTIVE To test the null hypothesis that there is no significant difference between the chitosan-containing and conventional nonfluoridated dentifrices in inhibition of enamel demineralization around orthodontic brackets. MATERIALS AND METHODS Sixteen orthodontic patients who were scheduled to have extraction of four first premolars for orthodontic reasons were divided into two groups after the power of the study was estimated. Patients in the experimental group were instructed to use chitosan-containing dentifrice (AloeDent), and patients in the control group were instructed to use nonfluoridated dentifrice (Sensodyne Mint). After 60 days, the teeth were extracted and longitudinally sectioned. The demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits and at occlusal and cervical points, 100 µm and 200 µm away from the edge. In all these positions, indentations were made at depths of 10, 20, 30, 50, 70, and 90 µm from the enamel surface. Analysis of variance (ANOVA) and Tukey test were used for statistical evaluation at P < .05 level. RESULTS ANOVA showed statistically significant differences for the factors of dentifrice type, position, and depth (P  =  .000). Statistically significant differences for microhardness values between two tested dentifrices were observed up to 20 µm of depth from the enamel surface (P < .05). Lower microhardness values were found for nonfluoridated dentifrice. Significant microhardness differences were also determined between materials at occlusal and cervical 0 µm positions (P < .05). At these positions, chitosan-containing dentifrice showed lower demineralization than the control. CONCLUSION Chitosan-containing dentifrice may reduce the enamel decalcification found in patients with poor oral hygiene. The null hypothesis is rejected.

Comparison of time-dependent changes in the surface hardness of different composite resins

Objective: The aim of this study was to evaluate the change in surface hardness of silorane-based composite resin (Filtek Silorane) in time and compare the results with the surface hardness of two methacrylate-based resins (Filtek Supreme and Majesty Posterior). Materials and Methods: From each composite material, 18 wheel-shaped samples (5-mm diameter and 2-mm depth) were prepared. Top and bottom surface hardness of these samples was measured using a Vickers hardness tester. The samples were then stored at 37°C and 100% humidity. After 24 h and 7, 30 and 90 days, the top and bottom surface hardness of the samples was measured. In each measurement, the rate between the hardness of the top and bottom surfaces were recorded as the hardness rate. Statistical analysis was performed by one-way analysis of variance, multiple comparisons by Tukeys test and binary comparisons by t-test with a significance level of P = 0.05. Results: The highest hardness values were obtained from each two surfaces of Majesty Posterior and the lowest from Filtek Silorane. Both the top and bottom surface hardness of the methacrylate based composite resins was high and there was a statistically significant difference between the top and bottom hardness values of only the silorane-based composite, Filtek Silorane (P < 0.05). The lowest was obtained with Filtek Silorane. The hardness values of all test groups increased after 24 h (P < 0.05). Conclusion: Although silorane-based composite resin Filtek Silorane showed adequate hardness ratio, the use of incremental technic during application is more important than methacrylate based composites.

The effect of the application of gaseous ozone and ND:YAG laser on glass‐fibre post bond strength

The aim of this study was to investigate the effects of the application of gaseous ozone and Nd:YAG laser on glass-fibre post bond strength. Forty-two madibular premolar roots were cut, endodontically instrumented and irrigated with 2.5% NaOCl. Post spaces were prepared and roots were divided into three groups (n = 14). The antimicrobial pretreatment was conducted as follows: gaseous ozone, Nd:YAG laser and control (no additional disinfection methods). Scanning electron microscope analysis was made for each group (n = 2). A resin cement was used for luting the posts. For push-out test, each root was cut horizontally (two cervical, two middle and two apical). Statistical analyses were performed with one-way anova (α = 0.05). Fracture types were observed. There was no statistically significant difference between the groups (P > 0.05). There were statistically significant differences in cervical and apical segments of laser and control groups (P < 0.05). The disinfection of the post spaces with Nd:YAG laser and ozone had no adverse effects on bond strength of glass-fibre post.

Demineralization properties of newly erupted and mature premolars around orthodontic brackets: an in-vivo study.

INTRODUCTION The aims of this study were to evaluate the in-vivo reaction of newly erupted enamel to demineralization around orthodontic brackets and to compare it with that of mature enamel. METHODS Thirteen orthodontic patients scheduled to have 4 first premolars extracted for orthodontic reasons were divided into 2 groups. Group 1 included 7 younger patients with newly erupted teeth (4 boys, 3 girls; mean age, 11.21 +/- 1.12 years; range, 11-13 years). Group 2 contained 6 adults with mature teeth (5 men, 1 woman; mean age, 34.64 +/- 4.01 years; range, 25-41 years). Brackets were placed, and, 30 days later, the teeth were extracted. These teeth were longitudinally sectioned, and demineralization was assessed by cross-sectional microhardness. Determinations were made at the bracket-edge composite limits and at occlusal and cervical points 100 mum away. Evaluations under the brackets and at the lingual surfaces were made as controls. In all these positions, 6 indentations were made at depths from 10 to 90 mum from the enamel surface. Analysis of variance (ANOVA) and Tukey tests were used for statistical evaluation at the P <0.05 level. RESULTS ANOVA showed statistically significant differences for tooth type, position, depth, and their interactions (P <0.05), except the tooth type and position interaction. The multiple comparison test showed less demineralization in the enamel around orthodontic brackets bonded to mature teeth campared with newly erupted teeth (P <0.05). CONCLUSIONS During the 30-day study period, the tooth enamel in the adult orthodontic patients was more resistant to demineralization than that of the younger patients.

Effects of three different bleaching agents on microhardness and roughness of composite sample surfaces finished with different polishing techniques

Background The aim of this study was to evaluate effects of different polishing methods and whitening agents on surface hardness and roughness of nano-hybrid composite resin. Material and Methods In total, one hundred twenty disc-shaped specimens were prepared to nano-hybrid composite (Charisma Diamond). 60 samples were used for microhardness measurements and the others were used for the evaluation of surface roughness. Samples were divided randomly into two subgroups (n = 30 each). In first group a low-viscosity liquid polishing agent (Biscover LV) was applied. In the second group, nothing was applied. All the samples were stored in distilled water at 37°C for 24 h. After initial measurements were completed, samples were divided randomly into three subgroups for bleaching application. 10% carbamide peroxide (Opalescence PF), 45% carbamide peroxide (Opalescence PF Quick), 38% hydrogen peroxide (Opalescence Boost) was applied. Then microhardness and surface roughness measurements of samples were repeated and data were recorded as final values for each sample. Results When the polishing techniques were compared, no signicant difference was observed in surface hardness and roughness. When the bleaching agents were compared, the 10% carbamide peroxide and 38% hydrogen peroxide containing bleaching agent groups showed statistically significant differences between pre- and post-procedure hardness values (p<0.05). Conclusions Office-type bleaching agent containing CP was observed to be more secure for composite resins than other bleaching agents. No negative effect of glaze materials on the protection of surface roughness and hardness of composite resin was observed. Key words:Composite resin, bleaching, surface hardness, surface roughness.

An in vitro evaluation of the effects of desensitizing agents on microleakage of Class V cavities

Background The aim of this study was to evaluate the effect of a desensitizing agent on microleakage of Class V cavities. Material and Methods 72 premolar teeth were used. There were 6 groups. Class V restorations were prepared with two different restorative materials (Equia fil, GC, America and Grandio, VOCO, Germany) and two adhesive systems (Clearfil SE Bond, Kuraray, Japan and S3 Bond Plus, Kuraray, Japan) with and without desensitizing agent (Gluma Desensitizer, Heraeus Kulzer, Germany). Restorations were polished with aluminum oxide abrasive discs. Then a range of 5 - 55C thermocycling was performed 10.000 times. The microleakage of restorations was examined with dye penetration method (Basic fuchsine). Bonferroni corrections and Kruskal-Wallis test were used to determine the significance of differences in occlusal and gingival dye penetration scores between groups. Results There was no stastistical significance between the occlusal and gingival microleakage scores within the groups were shown. Conclusions It can be concluded that use of desensitizing agent under both high viscosity glass ionomer restorative materials and resin composites doesn’t affect the microleakage. Key words:High viscosity glass ionomer cement, composite resin, desensitizing agent, microleakage.

Evaluation of different restoration techniques on fracture resistance of teeth with palatinal cusp fracture

Abstract We evaluated reattached tooth fragments in terms of fracture resistance in endodontically treated maxillary premolars with one remaining wall. In total, 60 double-rooted, mature, human maxillary premolars with double canals were used. Ten intact teeth were served as a control group without any application. After endodontic treatment, the palatal wall of the teeth was cut parallel to the horizontal axis on the cementoenamel junction using a diamond disc. The teeth were randomly divided into five groups (n = 10) and were restored as follows. Group 1: restored with composite resin; Group 2: palatal wall bonded to the teeth using adhesive resin, then restored with composite resin; Group 3: teeth restored as in Group 2, plus a post space prepared below 2 mm from the palatinal cusp horizontally, then fibre post bonded using adhesive resin cement; Group 4: cavity enlarged to a depth of 2 mm in the cusp of the palatal wall, then restoration performed as in Group 2; and Group 5: fibre post placed in the root canal and then restoration performed as in Group 1. Failure load testing was performed with a universal testing machine. Kruskal–Wallis and Conover’s multiple comparison tests were used to analyse the data. In the restoration groups the highest median load at failure was observed in Group 4, in which cusp capping was used; the lowest was found in Group 3, in which a horizontal fibre post was applied with the reattached tooth fragments.