Comparison of shear bond strength and residual adhesive remnants on the enamel surface after debonding of three different orthodontic molar tubes : A scanning electron microscope study.

BACKGROUND: The aim for this research was to evaluate and compare the impact, bond strength, and residual adhesive on the enamel surface after debonding of different orthodontic molar tubes. The tested materials were metal, composite, and newly introduced ceramic orthodontic molar tubes. MATERIALS AND METHODS: In all, 66 first molar teeth were randomly divided into three groups. Metal, glass-fiber composite and ceramic orthodontic molar tubes were bonded and shear bond strength (SBS) tests were performed. The adhesive remnant index (ARI) scores after debonding were recorded and the enamel surfaces were investigated using scanning electron microscopy (SEM) after the adhesives were cleaned. RESULTS: The mean SBS values of the metal and ceramic tube groups were significantly higher than that of the glass-fiber composite tube group. The highest SBS values were recorded for the ceramic tube group (11.09 ± 2.51 MPa). Failure typically occurred at the adhesive-enamel interface in the ceramic group, whereas the majority of the samples in the glass-fiber composite group showed failure at the adhesive-tube base interface according to ARI and SEM investigations. ARI 1 and ARI 2 scores were commonly observed for the metal tube group. CONCLUSIONS: All the molar tubes tested had generated clinically acceptable SBS values; however, the values for glass-fiber composite molar tubes were significantly lower than those for the ceramic and metal molar tubes. If the debonding procedure is performed carefully, the ceramic molar tubes may be an enamel-safe product for patients seeking fully esthetic orthodontic treatment.

Evaluation of Different Adhesive Resin Removal Methods after Debonding Ceramic Orthodontic Molar Tubes: A Scanning Electron Microscope Study.

Objectives: To evaluate and compare the impacts, bond strength, residual adhesive, and time invested on the enamel surface after debonding of recently introduced ceramic buccal molar tubes with different systems. Materials and Methods: Ceramic molar tubes were bonded to fifty-four maxillary molar teeth, and a shear bond strength (SBS) test was performed. The adhesive remnant index (ARI) scores were recorded, and the samples were divided into two groups for adhesive removal with low-speed instruments: tungsten carbide bur or diamond-coated micropolisher point. The time to clean the enamel surfaces was also noted down for each tooth. The enamel surfaces were investigated with scanning electron microscope (SEM) after adhesives were cleaned. Shapiro-Wilk's, Kolmogorov-Smirnov's, and Student's independent t tests were used for statistical analysis. Results: The mean SBS value of the tested ceramic molar tubes was 9.78 ± 1.85 MPa, and the majority of the samples were scored as ARI 1 and ARI 2. No statistically significant difference between PoGo micropolisher and TCB was found in terms of time values for surface cleaning. The enamel surface characteristics of TCB for adhesive remnant removal resulted in a better enamel surface than the single-step diamond polisher when the samples were investigated by using SEM. Conclusions: Ceramic molar tubes may be an enamel-safe product for patients seeking for fully aesthetic orthodontic treatment, if used in carefully handled clinical conditions. One-step polishing systems utilised with low-speed instruments could be used confidentially for cleaning the resin remnants on enamel after orthodontic treatment.

Effect of Orthodontic Brackets on the Accuracy of Apex Locators: A Pilot Study.

The purpose of this study was to evaluate the effect of metal orthodontic brackets on the accuracy of electronic apex locator (EAL). The actual canal lengths (ACL) of 40 mandibular incisor teeth were determined. Then, the teeth were randomly divided into two groups (n = 20). Orthodontic metal brackets were applied in the first group, and no brackets, in the second group. The working length of each tooth was measured with an EAL under 3 test conditions according to the distance between the lip clip and sample tooth. Data were analyzed using one-way repeated measures analysis of variance and Tukey's post hoc tests (p = 0.05). In the bracketed samples, when the lip clip was located at 1 cm and 2 cm from the samples. The mean differences between the EAL measurements and ACLs were statistically higher than those when the samples were located 3 cm from the lip clip (p < 0.05). There were also statistically significant differences between EAL measurements and ACLs in the bracketed samples located 1 and 2 cm from the lip clip (p < 0.05). In the nonbracketed group, the differences between EAL measurements and ACLs were not statistically significant in the samples located 1, 2, and 3 cm from the lip clip (p > 0.05). Use of orthodontic metal brackets can negatively influence the accuracy of the electronic apex locator when the distance between the lip clip and bracket was short. A minimum of 3 cm distance should be kept between the lip clip and tooth in order to make consistent electronic measurements.

Virgin Olive Oil, Soybean Oil, and Hank's Balanced Salt Solution Used as Storage Media on Periodontal Ligament Cell Viability.

Purpose: The purpose of this study was to compare the effects of virgin olive oil (VOO), soybean oil (SO), and Hank's Balanced Salt Solution (HBSS) on the vitality of periodontal ligament (PDL) cells of simulated avulsed teeth. Methods: Forty freshly extracted teeth were randomly divided into three experimental groups (n equals 10), one positive control group (n equals five), and one negative control group (n equals five). The experimental teeth were air-dried for 30 minutes and then soaked in one of the three storage solutions: HBSS, VOO, or SO. To quantify the number of viable cells, a collagenase-dispase assay was used. The viable PDL cells were determined via 0.4% Trypan blue staining. Data were statistically analyzed using the Kruskal-Wallis H test and Mann-Whitney U test with a significance level of 0.05. Results: The number of viable cells was significantly higher after storage in SO than in HBSS (P=0.004). There was no significant difference between SO and VOO in terms of PDL cell viability. Conclusion: Vegetable oils can be promising storage solutions for maintaining the periodontal ligament cell viability of avulsed teeth.

A new method for the treatment of unilateral posterior cross-bite: a three-dimensional finite element stress analysis study.

BACKGROUND: Stress relieving corticoto mies during the treatment of maxillary expansion are needed in adult patients. METHODS: Three-dimensional (3D) finite element model was prepared, and finite element analysis was processed to evaluate the stress distributions within the skull and maxillary teeth during surgically assisted rapid maxillary expansion (SARME) treatment. RESULTS: Expansion forces generated more stress on the corticotomy-applied part of the maxilla. The stress levels decreased dramatically above the corticotomy line. CONCLUSION: Asymmetric transveral maxillary expansion might be achieved from a symmetric force generating screw during SARME treatment. SARME osteotomies may concentrate the stress in the expanding maxilla and reduce the pain in other parts of the cranium.

A practical formula for determining growth.

PURPOSE: We aimed to establish a practical method to evaluate skeletal age using cervical vertebrae. METHODS: The study consisted of hand-wrist and cephalometric radiographs of 324 subjects (167 girls, 157 boys; age range, 7.3-17.2 years). Skeletal ages of the subjects were calculated from hand-wrist radiographs, and cervical vertebral bodies were measured using cephalometric radiographs. A single formula based on C3 and C4 vertebral body heights with different coefficients for each gender was derived using ridge regression analysis. RESULTS: The correlation coefficients for vertebral and hand-wrist bone age were 0.825 and 0.856 for girls and boys, respectively. The correlations among vertebral bone age and C3 and C4 vertebral body heights were also found to be significant. The intraclass correlation (ICC) score was found to be 0.914, which shows high consistency between the two measurements of the same investigator for each C3 and C4 vertebral body height result. CONCLUSION: The formula derived for evaluating skeletal age in cephalometric radiographs is reliable and can be applied to both girl and boy subjects for legal requirements or therapeutic needs of age estimation.

Changes in airway dimensions and hyoid bone position following class II correction with forsus fatigue resistant device.

OBJECTIVE: The objective of this study was to investigate the effects of fixed functional therapy on oropharyngeal airway dimensions and hyoid bone positions in Class II patients and make comparison with an untreated Class II group. MATERIALS AND METHODS: Eighteen patients (8 girls, 10 boys; mean age 13.62 ± 1.92 years) who were treated with Forsus Fatique Resistant Device (FFRD) and 19 patients (11 girls, 8 boys; mean age 12.74 ± 0.91 years) who served as control were enrolled. Cephalograms were used to assess linear, angular, and area measurements. Intragroup comparisons were made by paired t and Wilcoxon tests and intergroup comparisons were performed by independent t test. RESULTS: With respect to controls, FFRD group showed increased airway dimensions at soft palate (P < 0.05) and more forward positioning of the hyoid bone (P < 0.05). Dentoalveolar changes exhibited mesial movement of lower incisors and molars and reduction in overjet (P < 0.001) in FFRD group. CONCLUSIONS: Positive effects in oropharyngeal airway dimensions and increased values of hyoid bone displacement to a more forward position were found after fixed functional therapy. CLINICAL RELEVANCE: Treatment with fixed functional appliances is mostly based on mesial movement of mandibular dentition, which might influence changes in tongue posture. The present results might indicate that oropharyngeal airway dimensions may be affected by postural changes of the hyoid bone in consequence of dentoalveolar changes. Clinically, these may be considered especially in Class II cases with reduced airway dimensions.

Effects of a newly designed orthodontic miniplate platform for elevating the miniplate over the gingiva: A 3-dimensional finite element analysis.

INTRODUCTION: Miniplates are the treatment of choice for complex orthodontic and orthopedic problems. However, they require surgical placement and removal, and complications such as infection and mobility can occur. The aim of this finite element analysis was to investigate the effects of a newly designed miniplate platform to elevate the miniplate above the gingiva. METHODS: A bone block was modeled in 3 dimensions, and 2 N of force was applied on miniplates in 2 scenarios. In scenario 1, the miniplate was fixed with 2 miniscrews on both ends; in scenario 2, miniplate platforms were first seated on the cortical bone surface with their spikes fully penetrating, and then the miniplate was fixed on top with 2 miniscrews. RESULTS: The highest von Mises stress on the cortical bone decreased from 0.5 to 0.3 MPa when miniplate platforms were used. In scenario 2, the principal maximum stresses on the cortical bone around the miniscrews decreased from 0.42 and 0.48 MPa to 0.20 and 0.22 MPa, and the principal minimum stresses decreased from -0.45 and -0.48 MPa to -0.01 MPa. CONCLUSIONS: Miniplate platforms used to elevate the miniplate lowered the stresses generated on cortical bone around the miniscrews by distributing the stresses on the cortical bone surface. Patients can clean the miniplate more readily because it is elevated above the soft tissues. Placing the miniplate platforms requires only removing the gingiva with a punch, and their removal does not require flap surgery.

Effects of reverse headgear on pharyngeal airway in patients with different vertical craniofacial features.

The aim of this study was to investigate the effects of reverse headgear (RH) on pharyngeal airway morphology in two groups of Class III patients with different vertical craniofacial features in comparison with an untreated Class III group. Seventeen subjects (9 males, 8 females; mean age 11.3 ± 0.98 years) with optimum vertical growth and 17 subjects (10 males, 7 females, mean age 11.5 ± 1.1 years) with a vertical growth pattern treated with a removable intra-oral appliance and a Delaire type facemask were included. An untreated Class III control group of 11 subjects (8 males, 3 females, mean age 9.1 ± 1.1 years) was included to compare the treated groups. The paired t-test for intragroup and one-way ANOVA for intergroup comparisons were performed. The relationships between changes in the craniofacial morphology and airway were assessed by Spearman correlation analysis. The airway dimensions at the adenoid side and soft palate were increased in the treatment groups compared to the control group (p < 0.05). The nasopharyngeal area demonstrated a significant difference in normodivergent and control subjects (p < 0.05). No significant difference was found in the airway morphology due to different vertical features. The effect of RH treatment on the sagittal airway dimensions revealed no significant difference between different vertical craniofacial features in the short term.

Evaluation of airway dimensions and changes in hyoid bone position following class II functional therapy with activator.

AIM: The aim of this study was to evaluate the long-term effects of Class 2 functional treatment on airway dimensions and positional changes in hyoid bone and compare it with that of an untreated Class 2 control group. METHODS: Lateral cephalograms of 16 patients (eight girls, eight boys, mean chronological age = 11.36 ± 0.77 years) who were treated with activator and 19 patients (11 girls, eight boys, mean chronological age = 12.14 ± 0.65 years) who served as control were used for linear, angular and area measurements regarding airway track and hyoid bone. Statistics. Intra-group comparisons were performed by paired t-test and Wilcoxon test, whereas independent t-test and Mann Whitney-U were used for inter-group comparisons. RESULTS: During treatment (T2-T1), nasopharyngeal height and nasopharyngeal area increased (p < 0.05) and hyoid bone moved downward (H-SN; p < 0.001) and forward (H-C3; p < 0.01). During retention period (T3-T2); nasopharyngeal (p < 0.01) and oropharyngeal area increased (p < 0.05). H-SN (p < 0.01) and C3-H distances (p < 0.05) increased. Hyoid bone position exhibited significant changes (H-SN, p < 0.001; C3-H, p < 0.01). The increases in C3-H in long-term was more in the activator group than control (p < 0.05). CONCLUSIONS: In growing Class 2 patients with mandibular deficiency and airway track without obstructions, functional appliance treatment provided favorable effects on nasopharyngeal and oropharyngeal area throughout the retention period.

Effect of premolar extraction on mandibular third molar impaction in young adults.

OBJECTIVE: To test the null hypothesis that orthodontic therapy with or without premolar extraction does not result in any difference in third molar impaction. MATERIALS AND METHODS: Two groups were formed: 22 patients in one group with first premolar extractions and 22 patients in the other group without extractions. All patients were nongrowing subjects who had normal gonial angles and were skeletal Class I at the beginning of treatment. The available space for third molars, inclination of second and third molars, and angle between the second and third molars were evaluated. Also, the correlation of measured parameters and type of orthodontic therapy with the eruption of third molars was evaluated. RESULTS: Of the third molars, 81.8% were impacted in the nonextraction group and 63.6% were impacted in the extraction group. Impaction of mandibular third molars was significantly correlated to the pretreatment and posttreatment inclination of third molars and the angle between the second and third molars. In the extraction therapy group, the retromolar distance increased significantly with a mean of 1.30 ± 1.25 mm. CONCLUSIONS: When the inclination of the third molar is inconvenient, the tooth may remain impacted even if there is enough retromolar space.

Evaluation of different enamel conditioning techniques for orthodontic bonding.

OBJECTIVE: The aim of this study was to compare the effects of different enamel conditioning techniques for bracket bonding. METHODS: Ninety-one human premolars were randomly divided in six groups of 15 specimens each. The enamel surfaces of the teeth were etched with 35% orthophosphoric acid in Group 1, with a self-etching primer in Group 2, sandblasted in Group 3, sandblasted and etched with 35% orthophosphoric acid in Group 4, conditioned by Er:YAG laser in Group 5 and conditioned by Er:YAG laser and etched with 35% phosphoric acid gel respectively in Group 6. After enamel conditioning procedures, brackets were bonded and shear bonding test was performed. After debonding, adhesive remnant index scores were calculated for all groups. One tooth from each group were inspected by scanning electron microscope for evaluating the enamel surface characteristics. RESULTS: The laser and acid etched group showed the highest mean shear bond strength (SBS) value (13.61 ± 1.14 MPa) while sandblasted group yielded the lowest value (3.12 ± 0.61 MPa). CONCLUSIONS: Although the SBS values were higher, the teeth in laser conditioned groups were highly damaged. Therefore, acid etching and self-etching techniques were found to be safer for orthodontic bracket bonding. Sandblasting method was found to generate inadequate bonding strength.

Post-treatment evaluation of a magnetic activator device in Class II high-angle malocclusions.

SUMMARY: The purpose of this study was to evaluate changes in dentofacial growth before, during, and after use of a magnetic activator device (MAD) II in high-angle Class II division 1 patients. Lateral cephalometric and hand-wrist radiographs of 10 patients (six girls and four boys) with an average chronological age of 10 years 5 months were obtained at the beginning of the observation period (T1, 9.5 months), beginning of MAD II application (T2), at the end of the treatment (T3), and approximately 4 years after the end of treatment (T4). Thirteen linear, 1 ratio, and 10 angular measurements were evaluated. Paired t-tests were used for statistical evaluation of differences that occurred between the time points. The increase in gonial angle, GnGoAr angle, S-N, Co-Gn, Go-Ar, ANS-Me, S-Go, and N-Me distances and the decrease of overjet, U1-NA distance, and ANB angle were statistically significant during the treatment. At T4, there was a decrease in gonial angle and U1-NA distance, which was significant. The changes as a result of treatment were stable at T4.

Tensile bond strength of lingual orthodontic brackets with adhesive systems.

AIM: To study in vitro the bond strength of three adhesive systems on lingual brackets. METHODS: Forty-five extracted human mandibular premolars were randomly divided into three groups of 15 specimens each. All brackets (Stealth lingual brackets) were bonded with Transbond XT Light Cure Adhesive. In group 1, the conventional primer was used; in group 2, Transbond Moisture Insensitive Primer was employed; and in group 3, an antimicrobial self-etching primer (Clearfil Protect Bond) was used. RESULTS: The highest mean bond strength values were observed when Clearfil Protect Bond (13.54 ± 0.58 MPa) was used and the lowest after applying the conventional Transbond XT primer (6.41 ± 0.43 MPa). The mean bond strength in group 2 was 8.20 ± 0.50 MPa, which was significantly higher than that of group 1. CONCLUSION: Besides its antimicrobial effect, Clearfil Protect Bond results in high bond strength values. Therefore, this product might be preferable when bonding lingual brackets.

The effect of herbal teas on the shear bond strength of orthodontic brackets.

The present study was conducted to evaluate the effects of some types of herbal tea on the shear bond strength (SBS) of orthodontic brackets to enamel surfaces. The brackets were bonded with Transbond XT to 90 extracted human premolar teeth and divided equally into six groups, that is, black, mint-mate herbal, mint-lemon herbal, and rosehip fruit tea and two control groups, Coca-Cola and distilled water. All groups were conditioned for three 5-minute sessions with equal intervening intervals for 90 days. The initial pH, SBS, and adhesive remnant index (ARI) of the groups were evaluated and the data were analysed statistically by Kruskal-Wallis and Mann-Whitney U-tests, one-way analysis of variance, and Duncan and Z-tests, respectively. Rosehip fruit tea (2.4 +/- 0.07) and Coca-Cola (2.5 +/- 0.05) had the lowest pH values. Coca-Cola (6.04 +/- 1.11 MPa) and rosehip fruit tea (7.26 +/- 1.11 MPa) significantly reduced the SBS to enamel (P < 0.001). The SBS results for the other groups were similar (P > 0.05). Except for the Coca-Cola group (ARI score = 0), fracture sites for all other groups were similar with the majority of bond failures at the enamel-adhesive interface (ARI score = 1). Although this experiment could not completely replicate the complex oral environment, it seems to confirm that Coca-Cola and rosehip fruit tea may be a causative factor in bracket-enamel bonding failure.

Effect of light-cured filled sealant on shear bond strength of metal and ceramic brackets bonded with a resin-modified glass ionomer cement.

INTRODUCTION: Our objective was to evaluate the effects of a highly filled light-cured sealant (HFLCS) on the shear bond strength and bond failure site of metal and ceramic brackets bonded with resin-modified glass ionomer cement (RMGIC). METHODS: Eighty freshly extracted maxillary premolars were randomly divided into 4 groups (20 in each group). In all groups, the teeth were etched with 37% phosphoric acid for 20 seconds, and RMGIC (Fuji Ortho LC, GC Europe, Leuven, Belgium) was used for bracket bonding. In groups 1 and 3, the brackets were bonded directly to etched enamel surfaces; in groups 2 and 4, the etched enamel was covered with HFLCS (Pro Seal, Reliance Orthodontic Products, Itasca, Ill). Groups 1 and 2 received metal brackets, and groups 3 and 4 had ceramic brackets. The specimens were stored in distilled water at room temperature for 24 hours and subsequently tested in shear mode with a universal testing machine. After debonding, the teeth and the brackets were examined under a stereomicroscope (model SMZ-1B, Nikon, Osaka, Japan) at 20-times magnification to assess the residual adhesive on the tooth surfaces. RESULTS: Interaction between HFLCS and bracket type was not statistically significant (P = 0.15). Pretreatment with HFLCS did not cause a statistically significant change in the shear bond values of either metal or ceramic brackets (P = 0.38). Shear bond values of the ceramic brackets were higher than those of the metal brackets independent of HFLCS application (P <0.001). No significant differences were found in bond failure modes in the 4 groups. CONCLUSIONS: HFLCS application on enamel etched with 37% phosphoric acid did not affect the bond strength values and the bond failure modes of metal and ceramic brackets bonded with RMGIC. RESULTS: Interaction between HFLCS and bracket type was not statistically significant (P = 0.15). Pretreatment with HFLCS did not cause a statistically significant change in the shear bond values of either metal or ceramic brackets (P = 0.38). Shear bond values of the ceramic brackets were higher than those of the metal brackets independent of HFLCS application (P <0.001). No significant differences were found in bond failure modes in the 4 groups. CONCLUSIONS: HFLCS application on enamel etched with 37% phosphoric acid did not affect the bond strength values and the bond failure modes of metal and ceramic brackets bonded with RMGIC.

Effect of fluoride-releasing light-cured resin on shear bond strength of orthodontic brackets.

INTRODUCTION: The aim of this study was to analyze the effect of an enamel-protective resin on the shear bond strength (SBS) of orthodontic brackets bonded with self-etching primer. METHODS: Eighty extracted premolars were randomly divided into 4 groups of 20, and metal brackets were bonded. Group 1 specimens were bonded with Transbond Plus self-etching primer (3M Unitek, Monrovia, Calif) and no fluoride resin; in group 2, a fluoride-releasing resin (Ortho-Coat, Pulpdent, Watertown, Mass) was used with the Transbond Plus self-etching primer; group 3 teeth were bonded with a new antimicrobial self-etching primer (Clearfil Protect Bond, Kuraray Medical, Osaka, Japan) with no fluoride resin; and the same protocol was used in group 4 with an application of Ortho-Coat. A universal testing machine was used to determine the SBS, and the adhesive remaining after debonding was assessed. RESULTS: There was no difference in SBS whether fluoride-releasing resin was used. Groups 3 and 4 had higher SBS values than the other groups (P <0.001). The Kruskal-Wallis test showed no significant differences in the adhesive remnant index (chi-square = 0.019, P = 0.990). CONCLUSIONS: The application of enamel-protective resin did not affect the bond strength of orthodontic brackets to enamel with self-etching primer systems.

Temperature rise and shear bond strength of bondable buccal tubes bonded by various light sources.

The objective of the present investigation was to determine the intrapulpal temperature changes and to compare the shear bond strength (SBS) of bondable buccal tubes bonded by high-intensity light sources. Ninety caries-free human first molar teeth extracted for periodontal reasons were used. For the temperature measurement test, 30 teeth were randomly divided into three groups (n = 10) whereas 60 teeth were used in three groups (n = 20) for SBS testing. Three light sources, high-intensity halogen, blue light-emitting diode (LED), and xenon plasma arc (PAC), were used for polymerization of Transbond XT. Temperature variations (Delta T) were recorded by a K-type thermocouple wire connected to a data logger. For SBS testing, a universal testing machine was used at a crosshead speed of 1 mm/minute until buccal tube bonding failure occurred. Data were analyzed using the Kruskal-Wallis test. The high-intensity halogen light resulted in significantly (P < 0.01) higher intrapulpal temperature changes than the LED or PAC. The results of the shear bond test revealed significant (P < 0.05) differences only between the halogen and LED groups. The findings of the present investigation showed that high-intensity curing devices can safely be used in bonding buccal tubes to molar teeth without causing a deleterious effect on the dental pulp.

Effects of Class II activator and Class II activator high-pull headgear combination on the mandible: a 3-dimensional finite element stress analysis study.

INTRODUCTION: The aim of this study was to evaluate the effects of the Class II activator and the Class II activator high-pull headgear (HG) combination on the mandible with 3-dimensional (3D) finite element stress analysis. METHODS: A 3D finite element model of the mandible was constructed from a dry human mandible. To investigate the effects of the Class II activator, a 3D model of the lower part of this appliance was constructed and fixed on the mandibular model. The Class II activator high-pull headgear model was established as described, and an extraoral traction force of 350 g was directed from the middle of the Class II activator to the top of the mandibular condyle. The stress regions were studied with the finite element method. RESULTS: The regions near the muscle attachment areas were affected the most. The inner part of the coronoid process and the gonial area had the maximum stress values. CONCLUSIONS: Both functional appliances can cause morphologic changes on the mandible by activating the masticatory muscles to change the growth direction.