Ahmet Yalcin Gungor

Bleaching and Desensitizer Application Effects on Shear Bond Strengths of Orthodontic Brackets

OBJECTIVE To evaluate the effects of bleaching and desensitizer application on shear bond strengths of orthodontic brackets. MATERIALS AND METHODS Forty-eight extracted human premolar teeth were randomly assigned to 4 groups of 12 each. The first group of teeth was bleached with a 35% hydrogen peroxide office bleaching agent. The second group was bleached the same as the first group and UltraEZ desensitizer was applied. No bleaching procedures were applied on the third and fourth groups. UltraEZ desensitizer alone was applied to teeth in the third group. The fourth group served as control. Orthodontic brackets were bonded with a LC (light cure) composite resin and cured with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a Universal testing machine. RESULTS The results showed that bleaching, bleaching plus desensitizer, and desensitizer procedures significantly reduced the bonding strengths of the orthodontic brackets (P < .05, P < .001, and P < .01, respectively). No statistically significant difference was found between bleaching, bleaching plus desensitizer, and desensitizer groups (P > .05). CONCLUSIONS Because bleaching and desensitizer application significantly affected shear bond strengths of orthodontic brackets on human enamel, they should be delayed until the completion of orthodontic treatment.

Effects of adhesion promoters on the shear bond strengths of orthodontic brackets to fluorosed enamel

The aims of this in vitro study were to evaluate the effect of enamel fluorosis on the shear bond strength (SBS) of orthodontic brackets and to determine whether adhesion promoter, Enhance LC, increases the bond strength of brackets to fluorosed enamel. Forty-five (30 fluorosed and 15 non-fluorosed) non-carious fresh human premolar teeth, extracted for orthodontic reasons and without any caries or visible defects, were used in this study. The fluorosed teeth were selected according to the modified Thylstrup and Fejerskov index, which is based on the clinical changes in fluorosed teeth. In groups 1 (fluorosed teeth) and 3 (control), the brackets were bonded with Light Bond composite resin and cured with a halogen light. In group 2, Enhance LC was applied to fluorosed enamel before bonding. After bonding, the SBS of the brackets was tested with a universal testing machine. One-way analysis of variance and Tukey multiple comparison tests were used to compare the SBS of the groups. Any adhesive remaining after debonding was assessed and scored according to the modified adhesive remnant index. The results showed that while fluorosis significantly reduced the bond strengths of the orthodontic brackets (mean 13.94 +/- 3.24 MPa; P < 0.01), Enhance LC significantly increased bond strength on fluorosed enamel (mean 18.22 +/- 5.97 Mpa; P < 0.05). Groups 1 and 3 had greater bond failures at the composite-bracket interface, whereas group 2 showed bond failure primarily at the enamel-composite interface.

Effects of contamination by either blood or a hemostatic agent on the shear bond strength of orthodontic buttons

Objective To evaluate the effects of contamination by either blood or a hemostatic agent on the shear bond strength (SBS) of orthodontic buttons. Methods We used 45 freshly extracted, non-carious, impacted third molars that were divided into 3 groups of 15. Each tooth was etched with 37% phosphoric acid gel for 30 s. Human blood or the blood stopper agent was applied to the tooth surface in groups I and II, respectively. Group III teeth were untreated (controls). Orthodontic buttons were bonded to the teeth using light-curing composite resin. After bonding, the SBS of the button was determined using a Universal testing machine. Any adhesive remaining after debonding was assessed and scored according to the modified adhesive remnant index (ARI). ANOVA with post-hoc Tukeys test was used to determine significant differences in SBS and Fishers exact test, to determine significant differences in ARI scores among groups. Results ANOVA indicated a significant difference between groups (p < 0.001). The highest SBS values were measured in group III (10.73 ± 0.96 MPa). The SBS values for teeth in groups I and II were significantly lower than that of group III (p < 0.001). The lowest SBS values were observed in group I teeth (4.17 ± 1.11 MPa) (p < 0.001). Conclusions Contamination of tooth surfaces with either blood or hemostatic agent significantly decreased the SBS of orthodontic buttons. When the contamination risk is high, it is recommended to use the blood stopper agent when bonding orthodontic buttons on impacted teeth.

In vitro evaluation of shear bond strengths of colour change adhesives.

The aims of this study were to test whether the shear bond strengths (SBS) of three commercially available colour change adhesives (CCAs), Transbond Plus Color Change Adhesive, Grēngloo, and Blūgloo, are different and to compare their bond strengths with a traditional light cure adhesive, Light Bond. Forty-eight human permanent premolar teeth extracted for orthodontic reasons and without any caries or visible defects were used in this study. The brackets were bonded with Light Bond (group I), Grēngloo (group II), Blūgloo (group III), and Transbond Plus CCA (group IV). After bonding, the SBS of the brackets were tested with a Universal testing machine. Analysis of variance indicated a significant difference between groups I and IV (P < 0.001). No significant difference was found between groups II, III, and IV (P > 0.05). Adhesive remnant index (ARI) scores for all groups were not significantly different (P > 0.05). Significant difference existed between the SBS of Transbond Plus CCA and Light Bond. Although Transbond Plus CCA yielded the lowest SBS values, no statistically significant difference was found between bond strength values of the three commercially available CCAs. All three CCAs can be safely used in orthodontic practice since they yielded acceptable bond strengths. A higher incidence of ARI scores 4 and 5 revealed that bond failures in all test groups were mainly at the adhesive interface.

Effects of severity and location of nonsyndromic hypodontia on craniofacial morphology.

OBJECTIVE To evaluate the effects of severity and location of nonsyndromic hypodontia on craniofacial morphology. MATERIALS AND METHODS A total of 154 patients with at least two or more congenitally missing teeth were selected and divided into two groups (group I [mild]: patients with two to five missing teeth; group II [severe]: patients with six or more missing teeth). The patients with hypodontia were divided into three groups according to the location of missing teeth in the dental arches (anterior, posterior, and both anterior and posterior) and location of missing teeth between the jaws (maxilla, mandible, and both maxilla and mandible). Fifty Class I patients without any missing teeth served as the control group. Twenty-one measurements were performed on lateral cephalograms. Intergroup differences for the severity and location of hypodontia were analyzed using analysis of variance (ANOVA) and post-hoc Tukey tests. RESULTS Significant decreases were found in mandibular plane angles (P < .05), upper and lower incisor measurements (P < .05), anterior (P < .001) and posterior (P < .05) face heights, and ramus height (P < .01), as well as a significant increase in the soft tissue convexity angle (P < .05) among the hypodontia groups and control group. These differences were more excessive in the severe hypodontia group. Upper lip-E plane measurements were significantly longer in the mandible group than in the maxilla group (P < .01). CONCLUSIONS Patients with congenitally missing teeth have different craniofacial morphologies. The severity and location of missing teeth have a significant effect.

Tooth sizes in nonsyndromic hypodontia patients.

OBJECTIVE To evaluate and compare the sizes of teeth in mild and severe hypodontia patients with those of healthy controls. MATERIALS AND METHODS Dental casts of 154 patients with two or more congenitally missing teeth were obtained. Patients were divided into two groups according to severity of hypodontia. Group I (mild) consisted of 118 patients with two to five missing teeth. Group II (severe) consisted of 36 patients with six or more missing teeth. In addition, a control group was included, which consisted of 50 patients who had an Angle Class I jaw relationship and no missing teeth. Mesiodistal and labiolingual dimensions of the teeth were measured with a digital caliper on dental casts. The independent-samples t-test was used to evaluate the effect of gender on measurements. Intergroup differences for mesiodistal and labiolingual dimensions were evaluated with analysis of variance and post hoc Tukey tests. RESULTS Statistically significant differences were found between girls and boys with hypodontia in the mesiodistal dimension of the mandibular first premolar and the labiolingual dimension of the mandibular lateral incisor (P < .01). Mesiodistal and labiolingual width measurements of the teeth of hypodontia patients showed statistically significant differences compared with the control group (P < .05). Most teeth showed significant dimensional reductions in severe hypodontia compared with mild hypodontia (P < .05). CONCLUSIONS The mesiodistal and labiolingual dimensions of teeth in both mild and severe hypodontia groups were smaller than those in control subjects. The reduction in size was more excessive in the severe hypodontia group. The teeth showing the greatest difference in tooth dimensions were the maxillary lateral incisor (in mesiodistal dimension) and the mandibular canine (labiolingual dimension).

Effects of different intracoronal bleaching methods on shear bond strengths of orthodontic brackets

OBJECTIVE To evaluate the effects of different intracoronal bleaching methods on the shear bond strengths (SBS) of orthodontic brackets. MATERIALS AND METHODS Sixty freshly extracted mandibular incisors were randomly divided into four groups (n = 15 per group). After filling the root canals, root fillings were removed 2 mm apical to the cementoenamel junction, and a 2-mm-thick layer of zinc-phosphate cement base was applied. Group 1 served as the control. Intracoronal bleaching was performed with hydrogen peroxide (Opalacence Endo, Ultradent products Inc, South Jordan, Utah) in group 2, sodium perborate (Sultan Healthcare, Englewood, NJ) in group 3, and 37% carbamide peroxide (Whiteness Super Endo, Dentscare, ltda, Joinville, Brazil) in group 4. Orthodontic brackets were bonded with a light cure composite resin and cured with an LED light. After bonding, the SBS of the brackets was tested with a Universal testing machine. RESULTS Analysis of variance indicated a significant difference between groups (P < .001). The highest values for SBS were measured in group 1 (10.15 ± 1.15 MPa). The SBS was significantly lower in groups 2, 3, and 4 than in group 1 (P < .001). The lowest values for SBS were measured in group 3 (6.17 ± 0.85 MPa). SBS was significantly higher in group 4 than in group 3 (P < .05). CONCLUSIONS Intracoronal bleaching significantly affected the SBS of orthodontic brackets on human enamel. Bleaching with sodium perborate affects SBS more adversely than does bleaching with other agents.

Effects of different bleaching methods on shear bond strengths of orthodontic brackets

OBJECTIVE To evaluate the effects of different bleaching methods on the shear bond strength (SBS) of orthodontic brackets. MATERIALS AND METHODS Forty-five freshly extracted premolars were randomly divided into three groups (n = 15 per group). In group I, bleaching was performed with the office bleaching method. In group II, bleaching was performed with the home bleaching method. Group III served as the control. Orthodontic brackets were bonded with a light cure composite resin and cured with an LED light. After bonding, the SBS of the brackets were tested with a Universal testing machine. RESULTS Analysis of variance indicated a significant difference between groups (P < .001). The highest values for SBS were measured in group III (20.99 ± 2.32 MPa). The SBS was significantly lower in groups I and II than in group III (P < .001). The lowest values for SBS were measured in group II (6.42 ± 0.81 MPa). SBS was significantly higher in group I than in group II (P < .001). CONCLUSIONS Both of the bleaching methods significantly affected the SBS of orthodontic brackets on human enamel. Bleaching with the home bleaching method affected SBS more adversely than did bleaching with the office bleaching method.

Comparison of the effects of rapid maxillary expansion and surgically assisted rapid maxillary expansion in the sagittal, vertical and transverse planes

Objective: The aim of this study was to evaluate and compare the effects of rapid maxillary expansion (RME) and surgically assisted RME (SARME) in the sagittal, vertical, and transverse planes. Study design: Orthodontic records of 28 patients were selected retrospectively and divided into two treatment groups. Group 1 comprised 14 patients (4 boys, 10 girls, mean age 14.2 ± 0.74 years) who had been treated with RME. Group 2 comprised 14 patients (4 boys, 10 girls, mean age 19.6 ± 2.73 years) who had been treated with SARME. Measurements were performed on lateral and posteroanterior cephalograms and dental casts obtained before (T0) and after (T1) expansion. Results: Statistically significant differences were found in soft tissue convexity angle, anterior face height, and upper nasal width in group 1, and in U1–NA length and posterior face height measurements in group 2 (P<.05). In both groups significant increases were found in interpremolar, intermolar, maxillary, and lower nasal widths and in anterior lower face height (P<.01). Statistically significant intergroup differences were found in the ANB angle (P<.05) and maxillary intercanine (P<.01) measurements. Conclusion: With both RME and SARME, successful expansion of maxillary dentoalveolar structures and nasal cavity and palatal widening were achieved. Sagittal plane effects of SARME were similar to those of RME on dental skeletal and airway measurements. Key words: Surgically assisted rapid maxillary expansion, Rapid maxillary expansion, Airway, Transverse deficiency.

Color differences between maxillar and mandibular incisors

Context: Color difference between maxillar and mandibular incisors is an anticipated subject, and it will help dentists during color matching. Aim: The aim of this study was to evaluate color differences of the maxillar and mandibular incisors and to find out relationships between gender and age. Materials and Methods: This study was conducted on 125 participants (51 males and 74 females) between 16-63 age groups and totally over maxillar and mandibular 480 healthy teeth by using spectrophotometer. Color differences between teeth were calculated by using ΔE formula. One way ANOVA statistical analysis determined statistically significant differences between maxiller-central and mandibular-canine teeth for ΔL and Δb parameters ( P Results: According to t -test result there were not a statistically significant color differences for women and men teeth ( P P Conclusion: Women have more lighter teeth than men. Maxillar canines are more yellow and Maxillar centrals are more lighter than other incisors. 16-27, 28-39 age groups have more lighter teeth than 52-63 age groups and 16-27 age groups have more yellow teeth than 40-51 age groups.