Adhesive Remnant Index Values Research Articles

A Novel Graphite Fluoride/Bioactive Glass-containing Orthodontic Primer with Antibacterial and Remineralization Properties: An In-vitro Study.

This study aimed to develop a novel orthodontic primer that incorporated graphite fluoride (GF) and Bioactive glass (BAG) and to investigate its cell viability, bonding strength, and enamel damage, as well as its antibacterial and remineralization properties. Nine groups were prepared by adding different concentrations of GF (1, 2, and 4 wt.%) and BAG (1, 3, and 5 wt.%) to Transbond™ XT orthodontic primer. The prepared primers were compared to the control primer in terms of cell viability, shear bond strength (SBS), adhesive remnant index (ARI), enamel damage index (EDI), and antibacterial test. Then, the groups with better antibacterial properties (GFBAG 1-1, GFBAG 4-1, GFBAG 4-3, GFBAG 4-5) were evaluated for the remineralization properties. All the prepared orthodontic primers with different concentrations of GF/BAG revealed acceptable cell viability levels, with comparable SBS and ARI values to the control primer (p>0.05). Simultaneously, the EDI was reduced, while the antibacterial properties were significantly enhanced when compared to the control group (p0.05). The result of remineralization properties revealed that the selected groups had significantly higher remineralization ability than the control group; this was most pronounced in the GFBAG 4-3 group. All the prepared GF/BAG orthodontic primers are biologically safe with adequate SBS, ARI, and EDI values for clinical application with enhanced antibacterial properties. The GFBAG 4-3 experimental primer reveals the best antibacterial and remineralization properties which require further in-vitro and in-vivo investigations as a preventive measure of white spot lesions.

Development of a graphene oxide/hydroxyapatite-containing orthodontic primer: An in-vitro study

Fixed orthodontic appliances increase the risk of enamel demineralization and the development of white spot lesions (WSLs). This study aimed to develop a novel orthodontic primer that incorporates graphene oxide (GO) and hydroxyapatite (HA), investigate their cell viability, bonding strength, and enamel damage, and evaluate their antibacterial and remineralization properties. Nine groups were prepared by adding different concentrations of GO (0.1, 0.25, and 0.5 wt%) and HA (2, 5, and 7 wt%) to Transbond™ XT orthodontic primer. After observing the surface morphology of the material by a Field Emission Scanning Electron Microscope (FESEM), the phase of the materials by X-ray diffraction (XRD), and their chemical compositions by Energy Dispersive X-ray spectroscopy (EDX). The prepared primers were compared to the control primer group in terms of cell viability, shear bond strength (SBS), adhesive remnant index (ARI), enamel damage index (EDI), and antibacterial test. Then the groups with higher antibacterial properties (GOHA 0.1–2, GOHA 0.1–5, GOHA 0.25–2) were selected to evaluate their remineralization properties. Primers with all the prepared concentrations of GO/HA revealed acceptable cell viability levels within the limit of the ISO standards with comparable SBS and ARI values with the control primer (p > 0.05). Simultaneously, the EDI significantly reduced, and the antibacterial properties enhanced when compared to the control group (p < 0.05). The result of remineralization properties revealed that the selected groups had significantly higher remineralization ability than the control group which was more pronounced in GOHA 0.25–2 group. All the prepared orthodontic primers with different concentrations of GO/HA are safe biologically with adequate SBS, ARI, and EDI values for clinical application with enhanced antibacterial properties. The GOHA 0.25–2 experimental primer reveals the best antibacterial and remineralization properties which require further in-vitro and in-vivo investigation as a preventive measure of WSL.

Impact of Laser and Ultrasound on Pain Intensity and Enamel Surface During Orthodontic Debonding (A Randomized Clinical Trial)

Introduction Orthodontic debonding procedures usually involve pain and discomfort. The purpose of this in vivo study was to evaluate the effectiveness of laser and ultrasound on pain management during orthodontic debonding along with its effect on the enamel surface. Materials and Methods 42 patients referred for orthodontic treatment at the Department of Orthodontics, University of Hama, were recruited. After finishing treatment, a randomized debonding was accomplished with one of three methods: group 1 (control group): bracket removing plier (KP-013-135-PMK ,CHIFA ,Germany); group 2: Er:YAG laser (Pluser, Doctor Smile, Italy); group 3: ultrasonic scalar (Woodpecker, UDS-J ,China) (n=14). The pain intensity was evaluated using numeric rating scale (NRS), and the amount of adhesive remnant was determined by The Adhesive Remnant Index (ARI). Data were subjected to analysis of variance (ANOVA) and Bonferroni test. Results The highest NRS values was observed with group 1 (3.86 ± 1.46), whereas the lowest values were recorded with group 2 (1.64 ± 1.15). Debonding brackets using Er:YAG laser produced significant lower pain intensity compared to plier and ultrasonic scalar (P &lt; 0.05). The ARI values recorded for group 1 were significantly higher than those of two other groups (p&lt;0.05), while there were no statistically significant differences between group 2 and group 3. Conclusion Debonding orthodontic bracket with Er: YAG laser reduce the pain intensity and discomfort. Additionally, Er: YAG laser appears as an alternative method to reduce the adhesive remnants were left on the tooth surface

In-vivo durability of Pro Seal in patients with fixed orthodontic appliances: A controlled clinical trial

This clinical trial aimed at studying the durability of an orthodontic sealant (Pro Seal) used on tooth surfaces for protection against white spot lesions. A total of 35 patients (18 females, 17 males; 17.57 ± 1.36 years) were recruited. Eligibility criteria included healthy patients of both sexes (age > 14 years), absence of labial caries, absence of defective enamel, absence of extensive restorations, and optimum oral hygiene. The participants received a single application of Pro Seal on the bonded teeth. The sealant covered the labial enamel surrounding the brackets. Participants were recalled monthly after sealant application, during which sealant layers were evaluated using an ultraviolet lamp. The assessment was realized using an index similar to the adhesive remnant index (ARI). A total of 30 participants completed the trial. ARI values dropped significantly (P < 0.001) and reached <1.5 at T1 on the index used. An ARI value of 2 was chosen as the threshold below which a tooth presented an insufficient sealant layer. The right and left sides of both jaws did not show any statistically significant difference (P > 0.05). ARI values of homolateral teeth revealed few statistically significant differences between upper and lower teeth. No statistically significant difference between the two sexes (P > 0.05) existed. No harm or disturbance was reported by any of the participants. This study demonstrated that a single application of Pro Seal is effective for 4 weeks and should be renewed monthly. No interjaw, intrajaw, or intersex significant differences were found.

Effect of Enamel Pretreatment with Pastes Presenting Different Relative Dentin Abrasivity (RDA) Values on Orthodontic Bracket Bonding Efficacy of Microfilled Composite Resin: In Vitro Investigation and Randomized Clinical Trial.

Bonding failure is a clinical issue frequently encountered in orthodontic practice. The aim of this study was to evaluate enamel pretreatment both in vitro and clinically using agents with different RDA values before brackets’ bonding, to assess if RDA can affect the Shear Bond Strength (SBS), Adhesive Remnant Index (ARI) and clinical failure rate of orthodontic brackets. For the in vitro study, 220 bovine teeth were pretreated with agents with different RDA values. Subsequently, brackets were bonded. For the clinical study, 20 patients underwent bonding of 20 brackets each with a split-mouth design. Low and high RDA toothpastes were used for enamel pretreatment. SBS, ARI and failures were recorded. Higher SBS values were found for teeth pretreated with lower RDA agents; conversely, lower SBS values were found for teeth pretreated with higher RDA agents (p < 0.05). For high ARI values, RDA increased too (p > 0.05). In the clinical study, a significantly lower failure rate was reported for teeth pretreated with low RDA toothpaste (2.5% in low RDA group, 7.0% in high RDA group; p < 0.05). No significant differences were assessed comparing the two dental arches and anterior and posterior sites. Enamel pretreatment with low RDA toothpastes could increase brackets’ survival rate. Further in vitro and clinical studies would be welcomed to confirm these findings.

Impact of fluoride-releasing orthodontic adhesives on the shear bond strength of orthodontic brackets to eroded enamel following different surface treatment protocols.

PURPOSE:To assess the impact of enamel surface treatment protocols and the types of adhesive materials on the shear bond strength (SBS) of brackets to eroded enamel substrate.MATERIALS AND METHODS:Eighty extracted premolars were randomly assigned to four main groups in which group C (no treatment) was the control group. The remaining groups were exposed to an erosion challenge through short-term acidic exposure to HCl solution (0.01 M, pH 2.3) for 30 s, with an agitation speed of 50 rpm at an environmental temperature of 25°C. The eroded enamel surface within each group was treated as follows: group N received no treatment; in group P, the eroded enamel was treated with 35% phosphoric acid (Ultradent Products, South Jordan, UT, USA) for 15 s, followed by a rinse for 10 s; and in group F, the eroded enamel was treated with fluoride gel (Bifluorid 12; Voco-GmbH, Cuxhaven, Germany) for 4 min. The brackets were bonded with either a resin composite adhesive (Transbond XT; light-cure adhesive, 3M Unitek, CA, USA) or resin-modified glass ionomer cement (Fuji Ortho LC-GC Corporation, Japan). The specimens were tested for SBS, and the bond failure was assessed according to the adhesive remnant index (ARI). Analysis of variance (ANOVA) and Tukey's post-hoc tests (P < 0.05) were used to compare the SBS of the groups. The ARI values between the groups were recorded.RESULTS:Statistically significant differences were found among the tested variables (P < 0.05). Group P showed the highest mean SBS values regardless of the type of adhesive used, and the difference was statistically significant (P < 0.05). The application of the fluoride gel showed no statistically significant improvement in SBS values. The failure mode distribution among the test groups indicated that failures at the adhesive–bracket interface were predominant in group C compared with the other study groups.CONCLUSIONS:Fluoride pretreatment, which was used to remineralize the eroded enamel surfaces before bonding, resulted in a decrease in the SBS of the orthodontic brackets in vitro compared with the other treated groups. The use of fluoride-releasing adhesive also enhances bonding to the eroded enamel surfaces.

Ultrastructural and physicochemical characterization of pH receptive chlorhexidine-loaded poly-L-glycolic acid-modified orthodontic adhesive.

This study aims to evaluate the feasibility of chlorhexidine (CHX)-loaded poly-L-glycolic acid (PLGA) nanoparticles as a modifier of a commercial orthodontic adhesive via the assessment of physicochemical, biological, and mechanical properties at tooth-bracket interface. CHX-loaded PLGA nanoparticles were synthesized using double emulsion-solvent evaporation method and characterized using transmission electron microscopy and Raman analysis. CHX-loaded PLGA nanoparticles in Transbond XT orthodontic adhesive were prepared using two different concentrations of the CHX (25 and 50%) and characterized for degree of conversion (DC), antimicrobial, and cytotoxicity testing. Bonded specimens were tested for shear bond strength (SBS) and adhesive remnant index (ARI) at tooth-bracket interface. The synthesized PLGA nanoparticles averaged between 60 and 80 nm in size. After loading CHX inside PLGA nanoparticles, the morphology of the PLGA nanoparticles was considerably changed. Orthodontic bracket bonded with 25% CHX-loaded PLGA-modified adhesive demonstrated DC scores similar to control group. Both 25 and 50% CHX-loaded PLGA-modified adhesive specimens showed higher antibacterial activity against S. mutans compared to control group. The least mean SBS values were exhibited by 50% CHX-loaded PLGA-modified adhesive samples, while a statistically significant difference was observed in the mean ARI values among all study groups at all-time points (p=.018). This study indicates that the addition of CHX-loaded PLGA nanoparticles in Transbond XT achieved stable bonds with enhanced antimicrobial and mechanical properties.

Evaluation of enamel roughness after the removal of brackets bonded with different materials: In vivo study

The aims of this in vivo study were to evaluate the effect of bonding with resin-modified glass ionomer cement (RMGIC) and to assess enamel surface roughness before and after the removal of brackets bonded with composite or RMGIC from the maxillary central incisors. Fifteen orthodontic patients were selected for the study. For each patient, the teeth were rinsed and dried, and brackets were bonded with composite (Transbond XT) and RMGIC (Vitremer Core Buildup/Restorative). At the conclusion of orthodontic treatment, their brackets were removed. Dental replicas were made of epoxy resin in initial conditions (before bonded) and after polishing with an aluminum oxide disc system. Adhesive remnant index (ARI) and surface roughness was measured on the dental replicas and data were evaluated statistically by Mann-Whitney and paired t-test, respectively. No bracket debonding occurred during patients' treatment periods. It was verified that the ARI values of the two maxillary central incisors were similar (p = 0.665). For both bonding materials, the ARI value of 3 was predominant. After polishing, surface roughness was similar in the composite and RMGIC groups (0.245 μm and 0.248 μm, respectively; p = 0.07). In both groups, enamel surface roughness values were significantly lower after polishing compared with the initial condition (p < 0.001). RMGIC promoted efficiency in cementing brackets without fail during treatment; the choice of composite or RMGIC materials was not a factor that influenced the roughness of the enamel surface, however, polishing led to smoother surfaces than those found at the beginning of the treatment.

Analysis of Chlorhexidine Modified Cement in Orthodontic Patients: A Double-Blinded, Randomized, Controlled Trial.

Objectives The aim of this study was to evaluate the microbiological and mechanical properties of glass ionomer cement (GIC) modified by chlorhexidine (CLX) for the purpose of cementing bands to the teeth of orthodontic patients. Materials and Methods Ten patients, between the ages of 19 and 33 years, in the initial stage of orthodontic treatment, were randomly designated to two groups using the split-mouth design ( n = 10). One group (GICEX) had bands cemented with GIC modified by CLX and a Control group (GIC), evaluated at time intervals before (T0), 3 months (T3), and 6 months (T6) after cementation. Total microbiological counts were performed, and color stability of tooth enamel, salivary pH, and the adhesive remnant index (ARI) were evaluated. Statistical Analysis The Friedman and Dunn’s tests, Mann–Whitney, one-way analysis of variance, and Tukey, and paired and non-paired t -tests ( p < 0.05) were used. Results In T3, there was evidence of significant reduction in the quantity of colony forming unit (CFU) in GICEX group in comparison with the Control ( p = 0.041). In T6, the quantity of CFU was similar to the quantity in T3 and significantly different to control ( p = 0.045); Control group demonstrated a similar quantity of CFU between the experimental time intervals ( p = 0.066). Salivary pH demonstrated significant difference only between the time intervals T0 and T6 ( p = 0.022). The tooth enamel color ( p = 0.366) and ARI ( p = 0.343) values demonstrated no significant changes. Conclusion The incorporation of CLX into GIC demonstrated effective antibacterial action, allowed a good bond of the cement to the enamel, a high rate of survival of the bands, did not change the color of the tooth enamel, and maintained the salivary pH at physiological levels.

PH‐receptive chlorhexidine‐loaded poly‐L‐glycolic acid platform delivery approach to stabilize adhesive‐orthodontic interface

AbstractThis study aimed to synthesize and characterize chlorhexidine (CHX)‐loaded poly‐L‐glycolic acid (PLGA) nanoparticles and to investigate the in vitro drug release in different pH conditions, antibacterial, cytotoxicity activity, and mechanical properties of CHX‐loaded PLGA‐modified Transbond XT adhesive at tooth‐bracket interface. PLGA nanoparticles with and without CHX were synthesized using emulsion diffusion method and characterized for morphology and chemical structure using transmission electron microscopy and Raman analysis. CHX‐loaded PLGA nanoparticles in Transbond XT orthodontic adhesive were prepared using two different concentrations of the nanoparticles (2.5 and 5 wt%) and characterized for degree of conversion (DC) using DC, antimicrobial MTT assay, and cytotoxicity testing. Bonded specimens were tested for shear bond strength (SBS) and adhesive remnant index (ARI) at the tooth‐bracket interface. The synthesized PLGA nanoparticles averaged between 60 and 80 nm in size. After loading CHX inside PLGA nanoparticles, the morphology of the PLGA nanoparticles was changed considerably into irregular shaped structures. Bracket samples treated with 5 wt% CHX‐loaded PLGA‐modified adhesive demonstrated the least mean DC scores. A 5 wt% CHX‐loaded PLGA‐modified adhesive specimens showed more profound antibacterial activity against Streptococcus mutans. The least mean SBS values were exhibited by 5 wt% CHX‐loaded PLGA‐modified adhesive samples, while a statistically significant difference was observed in the mean ARI values among all study groups at all‐time points (p = 0.018). A pH‐sensitive CHX release response was observed when loaded in PLGA nanoparticles. The formulated drug‐loaded nanocarrier exhibited remarkable physicochemical, spectral, and biological features.

Evaluation of a newly developed calcium fluoride nanoparticles-containing orthodontic primer: An in-vitro study

ObjectivesFluoride and calcium ions have the ability to reduce the formation of white spot lesions (WSL) in enamel. This study aimed to develop a novel orthodontic primer that incorporates calcium fluoride nanoparticles (nCaF2) and investigate its cytotoxic and physical properties as this primer could enhance the remineralization process when used with the conventional acid etching technique. Materials and methodsThree groups of the newly introduced primers were prepared by adding and mixing nCaF2 (Nanoshell Company, USA at 5%, 10%, 20% in weight) to Transbond™ XT orthodontic primers (3M-Unitek, Monrovia, USA). X-Ray Diffraction (XRD) was performed to verify and evaluate the phase of the nanopowders. Field Emission Scanning Electron Microscope (FESEM) observation was used to assess the homogeneity of tested primers, and Energy Dispersive X-Ray Spectroscopy (EDS) was performed to analyze elements of the prepared samples. The three primer groups were compared to the control primer (without the addition of nCaF2) in terms of cytotoxic behavior, homogeneity, agglomeration, shear bond strength (SBS), and adhesive remnant index (ARI). ResultsnCaF2 primers with all the prepared concentrations revealed good homogeneity with no apparent agglomeration after four months of mixing. Cytotoxicity of the new primers was higher than that of the control primer, but it was within the accepted limits of the ISO standards (70% cell viability). While the SBS and ARI values were comparable with the control primer (p > 0.05). ConclusionsThe newly developed orthodontic primers with different concentrations of nCaF2 (5%, 10%, and 20%) showed a homogenous distribution of nCaF2 within the primers with no apparent agglomeration, acceptable cytotoxic level, adequate SBS, and ARI. Future clinical testing of nCaF2-containing orthodontic primer as a preventive measure for WSLs during fixed orthodontic treatment is suggested.

Bond Strength of Metallic or Ceramic Orthodontic Brackets to Enamel, Acrylic, or Porcelain Surfaces.

Bonding strategies within different brackets and dental materials are still a challenge concerning adhesion and dental surface damage. This study compared the shear and tensile bond strength of orthodontic ceramic and metallic brackets to enamel, acrylic, and ceramic surfaces after thermal cycling. Dental surfaces were divided into three groups: enamel, ceramic, and acrylic. Each group received stainless-steel and ceramic brackets. After thermal cycling, specimens were randomly divided into two subgroups considering tensile (TBS) or shear bond strength (SBS) test. After the mechanical testing, scanning electron and optical microscopy were performed, and the adhesive remnant index (ARI) was determined. The two-way ANOVA full factorial design was used to compare TBS, SBS, and ARI on the surface and bracket type (α = 0.05). There were significant differences in TBS, SBS, and ARI values per surface (p < 0.001 and p = 0.009) and type of bracket (p = 0.025 and p = 0.001). The highest mean SBS values were recorded for a ceramic bracket bonded to an acrylic surface (8.4 ± 2.3 MPa). For TBS, a ceramic bracket bonded to acrylic showed the worst performance (5.2 ± 1.8 MPa) and the highest values were found on a metallic bracket bonded to enamel. The adhesion of metallic or ceramic brackets is enough for clinical practice although the damage of the enamel surface after debonding is irreversible and harmful for the aesthetic outcome of the teeth.

Shear Strength of Brackets Bonded with Universal Adhesive Containing 10-MDP after 20,000 Thermal Cycles

Objectives The aim of this study was to evaluate the shear bond strength of metal brackets bonded with different universal adhesive systems containing 10-MDP and Transbond Plus Self Etching Primer after 20,000 thermal cycles. Materials and Methods. A total of 130 sound bovine teeth were used, which are divided into 5 groups (n = 26) according to the adhesive system used: All-Bond Universal (Bisco), Ambar Universal (FGM), Clearfil Universal Bond (Kuraray), Single Bond Universal (3M/ESPE), and Transbond Plus SEP (3M/ESPE) as control. The adhesives were applied for 20 seconds and bonded with a resin Transbond XT (3M/ESPE). After this, the teeth were submitted to 20,000 cycles at 5°C and 55°C. Afterwards, the shear bond strength test was performed in a universal test machine (Instron 3342). The adhesive remnant index (ARI) was evaluated under a stereomicroscope at 10x magnification and scanning electronic microscopy (SEM, Hitachi 3030). The shear bond strength data were submitted to One-Way ANOVA (α = 0.05) and the ARI to the Kruskal–Wallis test (α = 0.05) and the ARI to the Kruskal–Wallis test (Results Statistical analysis showed that the universal adhesive systems presented mean shear bond strength values similar to Transbond Plus SEP (p < 0.05). The universal adhesive presented similar ARI values among them but differed from those of Transbond Plus SEP (p < 0.05). The universal adhesive presented similar ARI values among them but differed from those of Transbond Plus SEP (Conclusions The results show that universal adhesive systems may be used for bonding metal brackets if the orthodontist wants to maintain dental enamel health.

Evaluation of the effect of different surface conditioning methods on shear bond strength of metal brackets bonded to aged composite restorations

There are controversies regarding the most reliable conditioning method of the aged composite surface to ensure optimum bond strength. The purpose of this study was to evaluate the shear bond strength of metal brackets to microhybrid composite restorations after different surface preparation techniques. A total of sixty microhybrid composite samples were prepared using upper right central incisor celluloid crown as a mold. Samples were treated with 4 different surface conditioning methods: (1) etching, (2) sandblasting, (3) grinding, and (4) CO2 laser irradiation. Samples were then bonded with metal brackets and underwent shear bond strength testing. A scanning electron microscope was carried out and the data was analysed by one-way ANOVA and post-hoc Tukey test. Bond failure was examined by stereomicroscope and scored based on adhesive remnant index (ARI). Kruskal-Wallis test was used to compare ARI values (α=0.05). Shear bond strength values in the sandblasting group (17.18±1.53MPa) were significantly higher than the other groups. There was no significant difference between the grinding (12.87±3.38MPa) and laser (11.08±1.37MPa) groups (P=0.09). The lowest values were recorded in the etching group (6.78±1.69MPa). There was a significant difference in ARI scores among the four groups (P<0.001). ARI scores were mostly 2 and 3 in the sandblasting and grinding group, while in the etching and laser groups ARI was mostly 0 and 1. Surface preparation by sandblasting and CO2 laser provides clinically acceptable results with regards to bond strength and ARI score, however grinding and acid etching failed to produce the same results.

Dental Hygiene and Orthodontics: Effect of Ultrasonic Instrumentation on Bonding Efficacy of Different Lingual Orthodontic Brackets.

Dental hygienists are often faced with patients wearing lingual orthodontic therapy, as ultrasonic instrumentation (UI) is crucial for oral health. As the application of external forces can lead to premature bonding failure, the aim of this study was to evaluate the effect of UI on shear bond strength (SBS) and on adhesive remnant index (ARI) of different lingual orthodontic brackets. 200 bovine incisors were divided into 10 groups. Four different lingual (STB, Ormco; TTR, Rocky Mountain Orthodontics; Idea, Leone; 2D, Forestadent) and vestibular control (Victory, 3M) brackets were bonded. UI was performed in half of specimens, whereas the other half did not receive any treatment. All groups were tested with a universal testing machine. SBS and ARI values were recorded. Statistical analysis was performed (significance: P = 0.05). TTR, Idea, and 2D lingual brackets significantly lowered SBS after UI, whereas for other braces no effect was recorded. Appliances with lower mesh area significantly reduced their adhesion capacity after UI. Moreover groups subjected to UI showed higher ARI scores than controls. UI lowered SBS of lingual appliances of small dimensions so particular care should be posed avoiding prolonged instrumentation around bracket base during plaque removal. Moreover, UI influenced also ARI scores.

Surface modification for bonding between amalgam and orthodontic brackets.

OBJECTIVE:Testing of methods to enhance the shear bond strength (SBS) between orthodontic metal brackets and amalgam by sandblasting and different primers.MATERIALS AND METHODS:Three hundred samples of amalgam restorations (KerrAlloy®) were prepared in self-cured acrylic blocks, polished, and divided into two groups: nonsandblasted and sandblasted. Each group was divided into five subgroups with different primers used in surface treatment methods, with a control group of bonded brackets on human mandibular incisors. Following the surface treatments, mandibular incisor brackets (Unitek®) were bonded on the amalgam with adhesive resin (Transbond XT®). The SBS of the samples was tested. The adhesive remnant index (ARI) and failure modes were then determined under a stereo-microscope. Two-way analysis of variance, Chi-square, and Kruskal–Wallis tests were performed to calculate the correlations between and among the SBS and ARI values, the failure modes, and surface roughness results.RESULTS:There were statistically significant differences of SBS among the different adhesive primers and sandblasting methods (P < 0.05). The sandblasted amalgam with Assure Plus® showed the highest SBS (P < 0.001). Samples mainly showed an ARI score = 1 and mix-mode failure. There was a statistically significant difference of surface roughness between nonsandblasted amalgam and sandblasted amalgam (P < 0.05), but no significant differences among priming agents (P > 0.05).CONCLUSIONS:Using adhesive primers with sandblasting together effectively enhances the SBS between orthodontic metal brackets and amalgam. The two primers with the ingredient methacryloxydecyl dihydrogen phosphate (MDP) monomer, Alloy Primer® and Assure Plus®, were the most effective. Including sandblasting in the treatment is essential to achieve the bonding strength required.

Effect of acid etching on bond strength of nanoionomer as an orthodontic bonding adhesive.

Aims:A new Resin Modified Glass Ionomer Cement known as nanoionomer containing nanofillers of fluoroaluminosilicate glass and nanofiller 'clusters' has been introduced. An in-vitro study aimed at evaluating shear bond strength (SBS) and adhesive remnant index (ARI) of nanoionomer under etching/unetched condition for use as an orthodontic bonding agent.Material and Methods:A total of 75 extracted premolars were used, which were divided into three equal groups of 25 each: 1-Conventional adhesive (Enlight Light Cure, SDS, Ormco, CA, USA) was used after and etching with 37% phosphoric acid for 30 s, followed by Ortho Solo application 2-nanoionomer (Ketac™ N100, 3M, ESPE, St. Paul, MN, USA) was used after etching with 37% phosphoric acid for 30 s 3-nanoionomer was used without etching. The SBS testing was performed using a digital universal testing machine (UTM-G-410B, Shanta Engineering). Evaluation of ARI was done using scanning electron microscopy. The SBS were compared using ANOVA with post-hoc Tukey test for intergroup comparisons and ARI scores were compared with Chi-square test.Results:ANOVA (SBS, F = 104.75) and Chi-square (ARI, Chi-square = 30.71) tests revealed significant differences between groups (P < 0.01). The mean (SD) SBS achieved with conventional light cure adhesive was significantly higher (P < 0.05) (10.59 ± 2.03 Mpa, 95% CI, 9.74-11.41) than the nanoionomer groups (unetched 4.13 ± 0.88 Mpa, 95% CI, 3.79-4.47 and etched 9.32 ± 1.87 Mpa, 95% CI, 8.58-10.06). However, nanoionomer with etching, registered SBS in the clinically acceptable range of 5.9–7.8 MPa, as suggested by Reynolds (1975). The nanoionomer groups gave significantly lower ARI values than the conventional adhesive group.Conclusion:Based on this in-vitro study, nanoionomer with etching can be successfully used as an orthodontic bonding agent leaving less adhesive remnant on enamel surface, making cleaning easier. However, in-vivo studies are needed to confirm the validity of present findings.

Comparison of adhesion forces developed by foil mesh of various dimensions applied in combination with composites of different viscosity

The aim of this study was to determine what effect various combinations of particular bracket bases and composites of different viscosity have on adhesion force. Eighty extracted premolars, upper and lower, were randomly assigned to four groups of 20 teeth and the combinations of either flowable or paste composite and brackets with either 80-gauge or 100-gauge foil mesh were applied to their labial surfaces accordingly: group A: flowable composite+80-mesh base; group B: flowable composite+100-mesh base; group C: paste composite+80-gauge base; group D: paste composite+100-gauge base. Each sample was subjected to shear bond stress to failure using a Zwick Roell Z050 testing machine at 50N/min load. The load required to detach each bracket was recorded in N and subsequently converted to MPa. After debonding, each tooth was analysed under optical microscope at 12× magnification and photographed prior to calculation of the Adhesive Remnant Index (ARI). The paste composite showed greater adhesion strength than the flowable in all cases, but this was further increased when the 80-gauge, rather than the 100-gauge, mesh was used. No statistically significant difference in ARI values was found between the flowable groups (groups A and B), on the other hand, in the paste composite groups, a statistically significant difference was highlighted between the 80-gauge (group D) and 100-gauge (group C) mesh bracket bases. Both the density of the composite and the gauge of a mesh bracket base are able to influence bond strength and the bond failure interface.

Shear bond strength of orthodontic brackets bonded using halogen light and light-emitting diode at different debond times

The aim of this in vitro study was to compare the photoactivation effects of QTH (Quartz-Tungsten-Halogen) and LED (Light-Emitting Diode) on the SBS (Shear Bond Strength) of orthodontic brackets at different debond times. Seventy-two bovine lower incisors were randomly divided into two groups according to the photoactivation system used (QTH or LED). The enamel surfaces were conditioned with Transbond self-etching primer, and APC (Adhesive Pre-Coated) brackets were used in all specimens. Group I was cured with QTH for 20 s and Group II with LED for 10 s. Both groups were subdivided according to the different experimental times after bonding (immediately, 24 h and 7 days). The specimens were tested for SBS and the enamel surfaces were analyzed according to the Adhesive Remnant Index (ARI). The statistical analysis included the Tukey's test to evaluate the main effects of photoactivation and debond time on SBS. The Chi-square test was used to compare the ARI values found for each group, and no statistically significant difference was observed. The debond time of 7 days for QTH photoactivation showed statistically greater values of SBS when compared to the immediate and 24 h periods. There was no statistically significant difference between the QTH and LED groups immediately and after the 24 h period. In conclusion, bonding orthodontic brackets with LED photoactivation for 10 s is suggested because it requires a reduced clinical chair time.

Effect of resin-removal methods on enamel and shear bond strength of rebonded brackets.

The objective of this study is to determine (1) the effect of different resin-removal methods on shear bond strength (SBS) of rebonded brackets, (2) condition of the enamel surface, (3) time spent to remove resin remnants, and (4) the location of the bond failure. A total of 80 premolars were included in the study. Fifty of them were divided into five groups and bonded using Light Bondtrade mark sealant and Quick Curetrade mark adhesive. Ten of the samples were debonded, and the SBS of the first debonding was calculated. Forty brackets were debonded using pliers and examined by an optical microscope (16x) to determine the location of the bond failure interface, using a modified Adhesive Remnant Index (ARI). The remnant adhesives were cleaned with four methods: (1) low-speed tungsten-carbide bur (TCB), (2) high-speed TCB, (3) Sof-Lex finishing disks, and (4) microetcher. The brackets were rebonded, and a second set of SBS and ARI values were calculated and statistically evaluated. Thirty of the premolars were divided into five groups receiving the same resin-removal methods and examined by scanning electron microscope. Rebonded teeth had a greater SBS than the initial bonding, except in group 4. The rebonded SBS values were similar in groups 1-3, and only group 4 showed a statistical difference. Sof-lex discs were the most time-consuming procedures and left much adhesive remnant. The high-speed TCB was found to be the most hazardous to the enamel. The scarring of enamel after the debonding is inevitable but can be reduced.