Light-cured Adhesives Research Articles

Evaluation of the effects of different mouthwashes, acidic soft drinks, and herbal teas on shear bond strength of orthodontic stainless steel brackets: A stereomicroscopic study

Background: Premature debonding of brackets often turns out into orthodontic treatment failures and actual treatment delays. The aim of the present study was to evaluate the effects of different mouthwashes, acidic soft drinks, and herbal teas on the shear bond strength of metal (stainless steel) brackets used in orthodontic practice. Materials and methods: For the present study, 100 therapeutically extracted healthy premolar teeth with sound enamel surface were collected from patients who were scheduled for orthodontic treatment. The select teeth were cleansed, whereas the dried enamel surface was etched with 38% phosphoric acid for 15 s following which orthodontic stainless steel brackets (MBT 0.022 SLOT) were bonded with the help of composite resin (3M Unitek Transbond XT Light Cure Adhesive). The prepared teeth were divided into four groups depending on exposure to different mouthwashes, acidic soft drinks, and herbal teas. The shear bond strength values of the specimen were measured using a universal testing machine, whereas debonded surfaces were observed under a stereomicroscope. Statistical analysis was done using the Statistical Package for the Social Sciences (SPSS) version 18.0 (SPSS Inc., Chicago, IL, USA). One-way analysis of variance and Tukey’s multiple post hoc procedures were used for statistical analysis. P <0.05 was considered statistically significant. Results: The results obtained in the present study suggested that the highest mean shear bond strength observed was in case of Group II specimen with a mean value of 11.83 ± 1.92 MPa, whereas the least shear bond strength was observed in case of Group III specimen with a mean value of 10.33 ± 1.31 MPa, with the results being statistically significant (P = 0.014). Conclusions: Within the limitations of the present study, it was concluded that comparatively lesser/weaker shear bond strength values were observed in case of specimen belonging to Group III, wherein among the 30 teeth belonging to Group III, 12 teeth showed shear bond strength value of 9 MPa which was the lowest in the study. The following core competencies are addressed in this article: Practice-based learning and improvement, Patient care and procedural skills, Systems-based practice, Medical knowledge.

Comparison of Three Different Orthodontic Adhesives Bonded to Metallic and Ceramic Brackets: SEM and SEM/EDX Analysis (In Vitro Study).

To compare three different orthodontic adhesives (Transbond XT Light Cure Adhesive, Heliosit Orthodontic, Fuji Ortho LC) bonded to two types of orthodontic brackets: ceramic brackets (Fascination Roth 0.22) and metallic brackets (Topic Roth 0.22, Dentaurum). The study was performed on 18 human teeth (6 for each adhesive). The prepared teeth were divided into three groups according to the examination time. Subsequently, they were observed after 1, 2 and 3 weeks following bonding. After the experimental procedure, the teeth samples were cut in half along the longitudinal axis in the vestibulo-oral direction, fixed with conductive carbon cement, placed in a high-vacuum evaporator and then coated with carbon. One half of each sample was observed under a Field-emission gun scanning electron microscope (FEG-SEM Hitachi SU 8030, Japan), while on the second half of the samples qualitative (X-ray line-scans) and semi-quantitative point X-ray energy dispersive analyses (EDX) were performed with Thermo Noran (USA) NSS System 7, equipped with Ultra Dry detector (30 mm2 window). Transbond XT had an ideal bond with the enamel and the bracket base, with rare presence of microgaps and cracks in the enamel. Heliosit Orthodontic demonstrated a better bond relationship with the bracket base than the enamel, whereas in the latter the presence of microgaps in the bond was observed. The microphotographs of Fuji Ortho LC demonstrated many cracks inside the adhesive, and some of them continued to move forward into the enamel surface. Therefore, an impression of a very solid bond relationship with the enamel exists, with cracks being present in the enamel surface and never at the enamel-adhesive interface. Microgaps also appeared at the bracket-adhesive interface. Transbond XT is a highly filled composite resin and is an ideal orthodontic adhesive in each aspect examined, with an ideal enamel-adhesive and bracket-adhesive interface. Heliosit Orthodontic provides better bracket-adhesive interface compared to the enamel. Fuji Ortho LC as a solid resin-modified GIC provides a better enamel-adhesive interface, compared to the bracket base.

Mechanical and chemical surface treatment enhances bond strength between zirconia and orthodontic brackets: an in vitro study

ObjectivesTo assess the shear bond strength (SBS) between metal orthodontic brackets and zirconia after receiving different mechanical and chemical surface treatments, and different types of resin adhesive. The failure mode of each treatment protocol was also evaluated.Materials and methodsThe present in vitro experimental study consisted of six surface treatment protocols with two different resin adhesives. One-hundred and forty-four rectangular-shaped 3 mol% yttrium-stabilized tetragonal zirconia polycrystal blocks were milled, sintered, and embedded in acrylic resin. They were randomly divided into three mechanical (none, air abrasion, and bur grinding) and two chemical surface treatment conditions (no primer and Z-primer). The specimens were divided into two groups according to the resin adhesive received: self-cured (RelyX U200) and light-cured adhesives (Transbond XT). The SBS between the metal bracket and zirconia was tested using a universal testing machine (1-mm/min crosshead speed), and the failure mode was evaluated. Differences in SBS and failure mode were analyzed using Welch ANOVA followed by post-hoc comparison and Fisher’s Exact test, respectively.ResultsBur grinding produced the highest SBS, followed by air abrasion. Z-primer application typically provided a higher SBS regardless of resin adhesive used (p < 0.001). Without primer application, RelyX U200 provided a higher SBS than Transbond XT (p < 0.001). After grinding, using Z-primer and RelyX U200 resulted in a higher SBS than no primer and using Transbond XT (p < 0.001). Adhesive failure at the zirconia–adhesive interface occurred only when Transbond XT was applied without bur grinding, and when using Transbond XT after grinding, but no Z-primer application.ConclusionBur grinding combined with applying an MDP-containing primer and resin adhesive enhances the SBS between zirconia and metal orthodontic brackets.

Clinical performance of light-cured orthodontic adhesives for bonding brackets - an in-vitro study.

The dental profession is seeing a constant influx of new adhesive systems from manufacturers, each claiming to be more dependable than the last. This study assessed the bond strength and adhesive remnants of different light-cured adhesives used for bonding metal brackets to teeth. 80 extracted maxillary premolars with the sound crown structure were acid etched and bonded with brackets on their buccal surfaces utilizing primer and light-cured adhesives into four equal groups, which are Transbond XT, Heliosit, Enlight, and Bracepaste. Shear bond strength (SBS) for de-bonding the brackets were evaluated with Instron- testing machine after 48 hours. The de-bonded samples' adhesive remnant index (ARI) scores were also measured. The maximum mean SBS was found for Transbond XT (12.91 ± 2.0 MPa), followed by Bracepaste (12.87 ± 1.59 MPa), Enlight (11.77 ± 1.87 MPa), and lowest for Heliosit (10.93 ± 1.71 MPa). According to the four point scale, adhesive remnant index (ARI), Transbond XT has the least adhesive residue left on the tooth, followed by Heliosit. Enlight and Bracepaste have a similar distribution of adhesive, with both having a maximum amount left. It can be inferred that all groups involved demonstrated a satisfactory level of bond strength from a clinical perspective. Transbond XT is the preferred orthodontic adhesive over the other three adhesives due to its superior SBS and ARI properties.

Impact of a High-Power Light-Emitting Diode Unit With Reduced Curing Times on the Shear Bond Strength of Orthodontic Brackets and Their Adhesive Remnant Index Scores.

This study aims to evaluate the curing time minimally required for bonding stainless-steel (SS) brackets using a high-power light-emitting diode (LED) light curing unit (LCU) and examine the debonded enamel surface for adhesive remnant. Based on the LED LCU and curing time employed, 80 human maxillary first premolar teeth were equally segregated into four groups. Three groups were cured using a high-power LED unit (Guilin Woodpecker Medical Instrument Co., Ltd., Guilin, Guangxi, China) for one, two, and three seconds. The fourth group served as a control and was bonded with another intensive LED unit (Elipar™ S10 LED Curing Light; 3M, Saint Paul, Minnesota, United States) for 20 seconds. Transbond™ XT Light Cure Adhesive (3M, United States) adhesive was used for bonding the SS brackets. All the samples were exposed to shear bond strength (SBS) testing after a 24-hour immersion period in distilled water at 37°C. A stereomicroscope was used to examine and score the adhesive remnant on the debonded surface using a modified adhesive remnant index (ARI). Kruskal-Wallis-ANOVA and post-hoc Mann-Whitney U tests for multiple pairwise comparisons were performed to analyze the data. Time and intensity significantly affected the SBS (P<0.001). A higher SBS value (16.04 megapascals (MPa)) was obtained in the six-second group when compared to the three-second (11.58 MPa), one-second (10.69 MPa), and 20-second control (13 MPa) groups. The ARI was significantly affected by the curing method. Higher SBSs were recorded for the six-second group using the high-power LED. A greater ARI score is associated with a reduced curing duration and vice versa.

Evaluation of the Flash-Free Adhesive System for a 6-month Period: A Split-Mouth Trial.

To compare the adhesive pre-coated (APC) flash-free (FF) appliance system (3M Unitek) with an operator-coated (OC) system (Transbond XT Light Cure Adhesive Paste; 3M Unitek) in terms of bond failure, bracket survival, and chair time. This single-center study was planned with 30 non-extraction patients, 22 females and 8 males with an average age of 17 years and 5 months. A split-mouth design was used, and bonding time, failed brackets, reasons for failure, and adhesive remnant index (ARI) scores were noted. The data were analyzed with the chi-square, Kaplan-Meier, log-rank, and Mann-Whitney U tests. OC and FF adhesive-coated brackets demonstrated bond failure rates of 0.7% and 3.0%, respectively. Failure rates and survival rates presented a statistically significant difference (p=0.033). Although higher bond failure for the lower arch along with higher bond failure for the incisor teeth compared with the premolar teeth were found, these findings were not statistically significant (p=0.128; p=0.261, respectively). The effect of gender on the bond failure rate (p=0.463) and survival rate (p=0.473) was not statistically significant. A significant difference was obtained for the ARI scores (p=0.011). The bonding time for each bracket type (64.43 seconds for FF versus 98.97 seconds for OC) demonstrated a significant difference (p=0.174). The bond failure rate was higher for the FF APC brackets, but the chair time reduction during bonding was recorded. Therefore, it seems that FF APC brackets are promising. Trial registration: ISRCTNand ISRCTN26731749. Registered October 7, 2020-Retrospectively registered, https://doi.org/10.1186/ISRCTN26731749.

Survival rate of indirectly bonded brackets using single vs. two-component orthodontic adhesive: A 12-month split-mouth clinical trial

ObjectiveCompare the bonding survival rate of two distinct bonding materials: Ortho Solo + Gradia LoFlo Resin and single component GC Ortho Connect. Materials and MethodsIndirect bonding fixed appliance treatment was required for 26 consecutive patients, 8 males and 18 females, with a mean age of 22.1 +/- 4.2 years. All patients were treated with SWM (Straight-Wire Mirabella) technique (Sweden and Martina, Due Carrare, Padova, Italy). Each patient's bonding process followed a contralateral pattern. Firstly, a 37 % orthophosphoric acid etching gel was used for 20 s, subsequently the single or two components light-cured adhesives were applied through a split-mouth cross-arch procedure. The patients underwent a 12-month follow-up period and brackets failures were rebounded, but not further included in the study. Statistical analysis was performed to analyse the survival rate of the bonding materials and the influence of the variables, with a significant level of α = 0,05. ResultsThe GC Connect group was used on 349 teeth, while the Ortho Solo + Gradia group was used on 351 teeth, and the indirect debonding rate was respectively 17.5% and 12.8%. With respect to the total sample, statistically significant values were found for both sex and dental arch. The bracket’s survival rate for incisors, canines, premolars and molars was not significant. However, a higher debonding rate was clinically appreciable in upper and lower molars. ConclusionIn a 12-months observation period, considering all maxillary and mandibular teeth the indirect survival rate for the group GC Ortho Connect and Ortho Solo + Gradia was respectively 82.5% and 87.2%. Although the difference was not significant, a pronounced tendency to debonding for the single component group was appreciable from a clinically point of view.

Comparison of residual monomer amounts released from indirect bonding adhesives.

To quantify the amount of residual monomer released from orthodontic adhesives used in the indirect bonding technique and compare it to a direct bonding composite resin. Five hundred stainless steel orthodontic brackets were bonded on bovine incisors using five groups of bonding resins: Transbond XT (TXT), Transbond Supreme LV (SLV), Sondhi Rapid-Set (SRS), Transbond IDB (IDB), and Custom I.Q. (CIQ). Liquid samples were gathered on the first, seventh, 21st, and 35th days. Residual monomer release was measured from the liquid samples with a liquid chromatography device. In addition, the amount and shape of the adhesive between the tooth surface and the bracket base was evaluated using obtained electron microscopy images. The data were analyzed using analysis of variance, and a Tukey post-hoc test was applied. Hydroxyethylmethacrylate and bisphenol A-glycidyl methacrylate monomers were released by all study groups. Urethane-dimethacrylate was released from the TXT, SLV, IDB, and CIQ groups. Triethylene glycol dimethacrylate was released from TXT, SLV, IDB, and SRS groups. The amount of total monomer release was higher in chemically cured adhesives than in light-cured adhesives. Among the chemically cured adhesives, premix adhesives had the highest amount of total monomer release. The light-cured adhesives had less thickness. Light-curing adhesives have significantly less monomer release than chemically polymerized adhesives.

Shining A Light

First there were light-cured adhesives, then light-activated adhesives, and now we have dual-cured adhesives. Eamonn Redmond, director of Inseto, the UK and Ireland distributor of adhesives from Delo, provides an overview of all three

Do Different Types of Adhesive Agents Effect Enamel Demineralization for Orthodontic Bonding? An In Vitro Study

(1) Objective: The aim of this study was to compare the demineralization around brackets bonded with different types of adhesive agents in a cariogenic suspension environment. (2) Methods: In the study, 60 extracted upper first premolar teeth were divided into three groups with 20 teeth in each group. In Group 1, Transbond XT Primer + Transbond XT Light Cure Adhesive (3M Unitek, Monrovia, CA, USA), in Group 2, GC Ortho Connect Light Cure Adhesive (GC Crop, Tokyo, Japan) and in Group 3, Transbond™ Plus Self Etching Primer + Transbond XT Light Cure Adhesive (3M Unitek, Monrovia, CA, USA) adhesive agents were used. In Group 1 and 2, buccal enamel surfaces were etched for 30 s, washed for 15 s and dried for 15 s. All groups were bonded with Gemini metal (3M Unitek, Monrovia, CA, USA) brackets. Gingival, occlusal and proximal enamel surfaces of the brackets were measured with a DIAGNOdent pen (KaVo, Biberach, Germany), and demineralization values were recorded. Measurements were performed after bracketing (T0) and after 28 days in a cariogenic environment (T1), which was renewed every 48 h. The Kolmogorov–Smirnov test was used to determine whether or not the data were homogeneously distributed, the Wilcoxon test was used for comparisons within groups, and the Mann–Whitney U and Kruskal–Wallis tests were used for comparisons between groups. (3) Results: In all groups, demineralization values on all enamel surfaces of the brackets were found to be statistically significantly higher in the T1 period than in the T0 period (p &lt; 0.05). In the T1 period, demineralization values of occlusal enamel surfaces in Groups 1 and 2 were found to be significantly higher than in Group 3 (p &lt; 0.05). The amount of increase in occlusal enamel surface demineralization value between T0 and T1 periods in Groups 1 and 2 was significantly higher than in Group 3 (p &lt; 0.05). There was no statistically significant difference in demineralization values of proximal and gingival enamel surfaces between the groups in the T1 period (p &gt; 0.05). (4) Conclusion: Significantly less occlusal enamel surface demineralization was observed in teeth in which the Transbond™ Plus Self Etching Primer adhesive agent was not applied with acid etching.

Influence of Primer Pre-curing and Co-curing on Shear Bond Strength of Orthodontic Brackets Using Three Light-cure Adhesive Systems: An In Vitro Study.

This study aimed to evaluate the shear bond strength (SBS) of orthodontic brackets with primer pre-curing and co-curing using three light cure adhesive systems. In this in vitro study, 102 extracted premolar teeth mounted on self-cure acrylic resin blocks were separated into six groups based on primer pre-curing and co-curing with each group receiving stainless steel orthodontic premolar brackets bonded to the buccal surfaces. The following adhesives were used: Transbond XT (3M Unitek, CA, USA), Orthofix (Anabond Stedman, India), and Enlight (Ormco, India). In the groups with pre-curing, the primer was pre-cured for 20 seconds while in the groups with co-curing, the primer and adhesive were cured together. Shear bond strength tests and Adhesive Remnant Index (ARI) were assessed followed by an scanning electron microscope (SEM) view (×3000) of the enamel surface after debonding. Statistical analysis was done using a one-way analysis of variance (ANOVA) test. The descriptive statistics in the pre-cured groups showed a statistically significant difference. The highest mean SBS was observed for group I, i.e., Transbond XT with primer pre-curing (20.56 ± 3.22 MPa). The lowest mean SBS was for group IV, i.e., Orthofix with primer co-curing (7.57 + 0.49 MPa). The results of ANOVA revealed a significant difference among the groups. The ARI scoring and the SEM analysis also confirmed this finding. Shear bond strength of orthodontic brackets with primer pre-curing showed a better bond strength than brackets with co-curing. The ARI data suggested that the majority of bracket failure happened at the resin-bracket interface. Scanning electron microscope analysis also confirmed the ARI and SBS findings. During the bonding of orthodontic brackets, the primer can be co-cured where the primer and adhesive resin are cured simultaneously or pre-cured where the primer is cured separately. Most orthodontic clinicians to save time co-cure primer. Both these methods affect the SBS of brackets.

Effect of Different Types of Adhesive Agents on Orthodontic Bracket Shear Bond Strength: A Cyclic Loading Study.

Bracket failure is one of the most important problems encountered during fixed orthodontic treatment. For this reason, different types of adhesive agents have been developed over the years. Consequently, the aim of this study was to evaluate the shear bond strength of brackets bonded to teeth etched with a conventional acid etching method in a laboratory environment by using different types of adhesive agents and comparing the number of shear strokes. Sixty human maxillary premolars were divided into three groups and Gemini stainless steel metal brackets (3M Unitek, Monrovia, CA, USA) were bonded to all teeth. In Group 1, Transbond™ XT Primer (3M Unitek, Monrovia, CA, USA) and Transbond™ XT Light Cure Adhesive Paste composite (3M Unitek, Monrovia, CA, USA) were used. In Group 2, BracePaste® MTP Primer (American Orthodontics, Sheboygan, CA, USA) and BracePaste® Adhesive composite (American Orthodontics, Sheboygan, WI, USA) were used. In Group 3, Ortho Solo™ Primer (Ormco, Orange, CA, USA) and Grengloo™ Adhesive composite (Ormco, Brea, CA, USA) were used. The samples were subjected to a shear test with a closed-loop controlled, low-cycle fatigue machine with a capacity of 10 N and a crosshead speed of 300 mm/min. The number of shear strokes of the brackets was recorded. According to the Kruskal-Wallis and Mann-Whitney U tests performed on the data obtained, statistically significant differences were found between the groups in terms of the numbers of shear strokes (p &lt; 0.05). Significantly higher numbers of shear strokes and higher shear bond strengths were observed in Group 3 compared with Group 1 and Group 2 (p &lt; 0.05). There was no statistically significant difference between the numbers of shear strokes for Group 1 and Group 2 samples (p &gt; 0.05). To conclude the study, it was observed that the type of adhesive used had an effect on the bond strength of the bracket and that the Grengloo™ adhesive agent showed higher shear bond strength. It was observed that BracePaste® Adhesive and Transbond™ XT Light Cure Adhesive Paste adhesive agents had similar shear bond strengths.

Comparison of Bond Strength of Orthodontic Brackets Onto the Tooth Enamel of 120 Freshly Extracted Adult Bovine Medial Lower Incisors Using 4 Adhesives: A Resin-Modified Glass Ionomer Adhesive, a Composite Adhesive, a Liquid Composite Adhesive, and a One-Step Light-Cured Adhesive.

BACKGROUND This study aimed to compare the bond strength of orthodontic brackets onto the tooth enamel of 120 freshly extracted adult bovine medial lower incisors using 4 adhesives: a resin-modified glass ionomer adhesive, a composite adhesive, a liquid composite adhesive, and a one-step light-cured adhesive. MATERIAL AND METHODS The study group (120 freshly extracted bovine medial lower incisors) was divided into equal subgroups depending on the type of adhesive used to fix the brackets to the tooth enamel (n=30), and then according to the observation time (n=10). Orthodontic brackets were fixed onto the tooth enamel for 24 hours (T1), 3 months (T2), and 6 months (T3) using 4 types of adhesives: resin-modified glass ionomer adhesive Fuji Ortho LC, composite adhesive Transbond Plus Light Cure Band, flowable composite adhesive Transbond Supreme Low Viscosity, and a one-step light-cured adhesive GC Ortho Connect. Shear tests and fracture plane analyses were performed. RESULTS Statistically significant differences at time T1 were noted in the comparison of shear stress values when brackets were fixed with GC Ortho Connect adhesive compared to other adhesives (P<0.05), except for the Transbond Plus adhesive (P>0.05). At time T3, significant statistical differences occurred between GC Fuji Ortho LC and the other 3 adhesives (P<0.05). The fracture analysis showed that, regardless of the time function, adhesive-cohesive fractures without damage to the enamel were the most common for all the assessed materials. CONCLUSIONS Of the adhesives evaluated, GC Ortho Connect appears to be the most appropriate choice for bonding orthodontic brackets to the enamel surface.

Evaluation of shear bond strength and adhesive remnant index of metal APC™ Flash-Free adhesive system: A comparative in vitro study with APC™ II and uncoated metal brackets

The aim of this in vitro study was to compare the shear bond strength (SBS) and the adhesive remnant index (ARI) of the metal APC™ Flash-Free adhesive system, the APC™ pre-coated adhesive system and a conventional uncoated system. One hundred eighty-six freshly extracted human premolars were randomly divided into 3 groups and bonded by a single operator. Group A/Control Group (60 teeth): the manual bonding group treated with Transbond™ XT Light Cure Adhesive Paste (3M™ Unitek). Group B (60 teeth): treated with APC™II metal maxillary premolar precoated brackets. Group C (66 teeth): treated with metal maxillary premolar APC Flash-Free brackets. The teeth were then stored in distilled water at 37̊C for 24hours, and five hundred cycles of thermocycling were performed. The Shear Bond Strength (SBS) test was performed using an Instron Universal Testing Machine, and the adhesive remnant index (ARI) was determined using a dental optical microscope at ×25 magnification. The mean shear bond strength values showed differences between the three types of brackets (P=0.016; Anova). It was significantly higher with APC™II and lower with APC Flash-Free brackets; however, no significant differences were found between conventional and APC Flash-Free brackets (P-value=0.574). The distribution of the dichotomized ARI score was significantly different between the three brackets (P-value=0.049). The ARI score for APC Flash-Free brackets was higher with no significant difference between the conventional system and APC brackets (P-value=0.361). The mean SBS values were not significantly different between APC Flash-Free metal brackets and uncoated metal brackets. The APC Flash-Free metal system's bond failure occurred at the bracket-adhesive interface, with the highest percentage of teeth having more than 50% of the residual composite on the enamel after debonding.

Comparison Of Shear Bond Strength And Adhesive Remnant Index Between Different Adhesive Systems In Bonding and Rebonding of Orthodontic Brackets

Aim: The aim of this study was to compare the shear bond strength (SBS) and adhesive remnant index of stainless-steel brackets bonded with different orthodontic adhesive systems. Materials and Methods: In our study performed on 60 premolar teeth extracted for orthodontic reasons, MBT prescription 0.022'' stainless-steel brackets (Discovery Smart®, Dentaurum, Germany) were used. In teeth randomly divided into 3 groups, bonding was performed with Group 1: Trulock Light Activated Bonding System (RMO, USA), Group 2: Bisco Ortho Bracket Paste LC (Bisco, USA), Group 3: Transbond XT Light Cure Adhesive (3M, USA). SBS and residual adhesive indexes (ARI) were evaluated by breaking the samples. Adhesive residues were cleaned with tungsten carbide burs from the surfaces of the teeth, rebonding was made after sanding the brackets’ surfaces. SBS and ARI values were re-evaluated. One-way ANOVA, two-sample t-test and Mann-Whitney U tests were used for statistical analysis of the data, p &amp;lt;0.05 was considered statistically significant. Results: Statistically significant differences were observed between Group 1 and Group 2 in comparison to the first SBS values of three different orthodontic adhesive systems to enamel (p &amp;lt;0.05). Among the adhesive systems, only a statistically significant difference was found between the first bonding values and the rebonding values of Group 2 (p &amp;lt;0.05). There was no statistically significant difference between the first and rebond strengths of the other two adhesive systems. Rebonding values of three different orthodontic adhesive systems were very close to each other. Conclusions: The results of this study suggest that the adhesive systems developed for the bonding of orthodontic brackets to the enamel can show clinically enough bond strength even if the rebonding strengths of the falling stainless-steel brackets to the same enamel surfaces decrease slightly.

A comparative study of shear bond strength of four different light cure orthodontic adhesives: An in vitro study

To compare the shear bond strength and Adhesive Remnent Index (ARI) of metal brackets using four different bonding systems: Heliosit Orthodontic Bonding Material (Ivoclar Vivadent), Ormco Enlight Light Cure Adhesive, Transbond XT Light Cure Adhesive (3M UNITEK) and Light cured Orthofix (Anabond Stedman Pharma Research (P) Ltd. In the present study 120 extracted sound human upper bicuspids were taken and divided into four groups. Group 1: Heliosit Orthodontic Bonding Material (Ivoclar Vivadent), Group 2 : Ormco Enlight Light Cure Adhesive ,Group 3: Transbond XT Light Cure Adhesive(3M UNITEK) and Group 4: Light cured Orthofix (Anabond Stedman Pharma Research (P) Ltd. In all the groups (n = 120) orthodontic metal brackets were bonded with the four different light cure adhesives respectively and all the samples were evaluated for shear bond strength using Instron(3366) universal testing machine at a cross speed of 1 mm/min. The bracket failure mode was examined using Adhesive Remnant Index (ARI). The Inter group comparison (&amp;#62;2 groups) was done using one way ANOVA followed by pair wise comparison using post hoc test. Comparison of frequencies of categories of variables with groups was done using Chi square test. For all the statistical tests, p&amp;#60;0.05 was considered to be statistically significant, keeping α error at 5% and β error at 20%, thus giving a power to the study as 80%.: It was concluded that the mean shear bond strength of the Transbond XT was highest among the four adhesives studied. However all the adhesives tested exhibits adequate bond strength for clinical use and ARI scores was nearly same for the Transbond and Enlight adhesives studied.

Étude comparative des excès de colle autour des attaches métalliques préencollées APC™ Flash-Free

The aim of this in vitro study was to determine if there is a significant difference in the excess adhesive flash between the metallic APC™ Flash-Free adhesive system, the APC™ pre-coated adhesive system and a conventional uncoated system. One hundred eighty-six freshly extracted human premolars were randomly and blindly divided into three groups according to the type of brackets. Group A (control group n=60): The conventional uncoated metallic bracket (Victory, 3M Unitek®) with a Transbond XT™ Light Cure Adhesive Paste was used. Group B (n=60): The APC™ II metallic maxillary precoated premolar brackets was used. Group C (n=66): The metallic APC™ Flash-Free adhesive system without flash clean up was used. Images were taken at 40 magnifications in a dental microscope (Leica M320 for dental, Wetzlar, Germany) then analyzed with the ImageJ software and the area of excess adhesive flash was measured. The mean percentage was significantly different between the three groups (p<0.001; ANOVA). It was significantly smaller for brackets in the APC Flash-Free group (p<0.001), and the difference was not significant between conventional brackets and APC (p=0.224). The new technique seems to reduce the amount of excessive adhesive around orthodontic brackets.

Synthesis and performance of experimental resin-based dental adhesives reinforced with functionalized graphene and hydroxyapatite fillers

Functionalized graphene and hydroxyapatite fillers are proposed as reinforcing particles in light-cured adhesives for dental applications. Silica-silver-graphene (SiO2-Ag-Gr), silver-doped hydroxyapatite (HA-Ag), graphene and silver doped hydroxyapatite (HA-Ag-Gr), and regular silica (SiO2) as inorganic powders, together with bis-GMA (2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy) oligomers, as main components of the organic matrix, were synthesized. Light field transmission electron microscopy and electron diffraction proved the successful synthesis of the powders. The experimental adhesives showed a positive influence on local biocompatibility up to 6 months in an in-vitro simulation of clinically relevant environmental conditions and aging. Bonding to human dentin reveal a particular fracture pattern with preferential adhesion to the restorative material in contrast to the gold standard adhesive used as reference, which adheres preferentially to the tooth structure. Bond strength was slightly lower, initial bond reliability slightly improved, and the morphology of interaction with tooth structure similar to the reference. Functionalized graphene and hydroxyapatite fillers in dental adhesives have demonstrated their potential for use in dental applications.

Comparison of bond strength of different lingual retainer wires: An study

: Bonded retainers are extensively used after orthodontic treatment to maintain the achieved results. However, bond failure in the retainer system is a frequently observed problem, resulting in the loss of retainer function, leading to relapse.: The purpose of this in-vitro study was to compare the shear bond strength of different wire-composite combinations.: 144 extracted human premolars in pairs were divided into 6 groups of 12 samples each. The orthodontic retainer wires used were Flat woven wire (Leone), Dead soft retention wire (Ortho Classic USA) and two stranded twisted Leone ligature wire (0.018”). The composite that was used was Transbond XT adhesive (3M Unitek) and Enlight Light Cure Adhesive (Ormco). Retainer wires were bonded on the lingual surfaces of the teeth. 72 samples were subjected to debonding with a chisel head in a universal testing machine INSTRON. Comparisons of the means of shear bond strength values were made with one way ANOVA &amp; Tukey’s Post Hoc test.: Maximum shear bond strength was observed in group IA (Leone flat woven wire with Transbond XT). There was a statistically significant difference in the shear bond strength of different retainer wires.: Compared to other wire composite combinations, maximum shear bond strength was observed in Leone flat woven wire with Transbond XT composite. Therefore, it could be the wire-composite combination of choice for the bonded lingual retainer.

In vitro study evaluating the shear bond strength of metal brackets to lithium disilicate ceramic support using a universal adhesive

The number of adult patients who seek an orthodontic treatment is increasing. These patients often have lithium disilicate ceramic restorations. The orthodontist has to find a procedure to bond effectively brackets to these restorations. In 2011, a new family of adhesives was introduced, universal adhesives, which are capable of bonding to ceramic and are said “multi-mode” because they can be used in etching-rinse or self-etching protocol on tooth surface. The objective of this in vitro study was to evaluate the shear bond strength (SBS) of metal brackets to lithium disilicate ceramic support using a universal adhesive. Forty machinable lithium disilicate blocks (IPS e.max CAD, Ivoclar) were prepared according manufacturer’s instructions. Each specimen was randomly assigned to one of four groups (n=9 or 10) defined by the pretreatment protocol. Protocol 1: Hydrofluoric Acid 9% (HF) + Silane + Orthodontic adhesive (Transbond™ XT Light Cure Adhesive Primer, 3M ESPE), protocol 2: HF + Universal adhesive (UA) (Scotchbond Universal®, 3M ESPE), protocol 3: UA only, protocol 4: Monobond Etch & Prime® (Ivoclar) + UA. Then, a bracket of upper cuspid (3M ESPE) was bonded to each specimen with a composite resin (Transbond™ XT, 3M ESPE). SBS was measured between ceramic and bracket with a universal testing machine. A one-way ANOVA (ANalysis Of Variance) followed by Tukey’s post-hoc test was performed to investigate SBS differences between groups. Protocol 2 (43 MPa) and protocol 4 (36 MPa) showed the highest SBS values and were statistically different from protocol 1 (25 MPa) and protocol 3 (21 MPa). Despite the lower bond values obtained in the study, but higher than the minimum expected, the application of UA alone appears to be a safe procedure that seems to provide sufficiently strong and resistant bonding between the ceramic and the bracket. However, clinical studies are needed before a recommendation can be made.