Can a Self-etching Primer be Effective in Bonding Aligner Attachments to Different Types of Ceramics?

Objective: This in vitro study aimed to evaluate the effectiveness of pretreatment with a self-etching primer for bonding aligner attachments to lithium disilicate (LD) and monolithic zirconia (MZ) ceramics. Methods: Forty ceramics, including LD (n=20) and MZ (n=20), were divided into four study groups according to the surface pretreatments: LD specimens pretreated with universal primer (Monobond Plus, MP) after hydrofluoric acid etching (Group 1); MZ ceramics pretreated with MP after sandblasting (Group 2); LD ceramics pretreated with self-etching ceramic primer (Monobond etch & prime, MEP) (Group 3); and MZ ceramics pretreated with MEP after sandblasting (Group 4). The aligner composite (GC Aligner Connect) and universal adhesive (GPremio Bond) were used to prepare the resin attachments. The bond strength was evaluated by micro-shear bond strength (SBS) testing (0.1 mm/min) after thermocycling, and the remnant adhesive was scored according to the resin attachment remnant index (RARI). The SBS data were analyzed using ANOVA and Tukey tests, and the RARI scores were analyzed using the chi-square test. Results: Group 1 had the lowest SBS, and group 2 had the highest SBS. There were significant differences between the groups in terms of bond strength (p<0.05). The RARI scores showed no significant differences, regardless of the pretreatment and ceramic type. Conclusion: The use of a self-etching primer increased the bond strength of resin attachments on LD ceramics. For zirconia ceramics, both ceramic primers are recommended for aligner attachment bonding.

Effects of Surface Treatment and Thermocycling on the Shear Bond Strength of Zirconia-Reinforced Lithium Silicate Ceramic.

PURPOSE: To investigate the effects of different surface treatments and thermocycling on shear bond strength (SBS) be-tween resin cement and zirconia-reinforced lithium-silicate (ZLS) ceramic. MATERIALS AND METHODS: 96 ZLS ceramic specimens were randomly allocated to four different surface treatment groups: etch and silane (ES), etch and universal primer (EUP), self-etching primer (SEP), and sandblasting and silane (SS). Stan-dardized composite cylinders were bonded to surface-treated ZLS ceramic, after which SBS was obtained either after 24-h water storage only or with an additional 5000 thermal cycles (TC), resulting in eight subgroups (n = 12). After evaluation of failure mode under a stereomicroscope, representative SEM images were acquired. To examine areal average surface roughness (Sa), additional ZLS specimens were prepared and randomly allocated to 3 groups: hydrofluoric acid etching, self-etching primer, and sandblasting (n = 10). Supplementary specimens were examined using field-emission scanning electron microscopy (FE-SEM) (n = 2) and atomic force microscopy (AFM) (n = 2) to investigate their surface topographies. RESULTS: ANOVA showed a statistically significant difference in SBS following different surface treatment protocols after 24-h water storage (p < 0.001). However, TC groups revealed no statistically significant difference in their SBS (p = 0.394). All surface treated groups were significantly affected by TC (p < 0.001), except for the SS group (p = 0.48). Sa was signifi-cantly influenced by the different surface treatment protocols (p < 0.001). CONCLUSION: The ability of self-etching primer to achieve comparable bond strength with a less technique-sensitive ap-proach makes it a favorable alternative to ES for the surface treatment of ZLS ceramics.

Comparison of shear bond strength of orthodontic brackets bonded to human teeth with and without fluorotic enamel: A systematic review and meta-analysis of experimental in vitro studies.

The aim of this systematic review was to compare the shear bond strength (SBS) of orthodontic brackets bonded to human teeth with and without enamel fluorosis (EF) using conventional bonding interventions/techniques. An unrestricted search of indexed databases was performed with the following eligibility criteria: (a) human fluorotic teeth (experimental-group); (b) human teeth without fluorosis (control-group); (c) studies using phosphoric acid (PA) etching without air abrasion (AA), PA etching combined with AA, and application of self-etching primer (SEP) alone as bonding interventions/techniques and (d) measuring SBS in megapascals (MPa). Data screening, selection and extraction were performed by two reviewers. The risk of bias (rob) was assessed using the JBI Critical appraisal tool for Quasi-Experimental Studies. Meta-analyses were performed using a random effects model. The quality of available evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation approach. Ten in vitro studies were included. Subgroup analyses were performed for each intervention type. The SBS was significantly lower in fluorotic teeth when PA was used without AA (mean difference = 3.26 MPa, confidence interval: [1.00, 5.52]); and there were no significant differences for the PA combined with AA and SEP interventions. All studies had a low rob. The overall level of evidence was at best low. The SBS is lower in teeth with EF when traditional PA is used. No significant differences were found in SBS between teeth with and without EF when PA is used with AA or when SEP is used alone.

Durability of resin bonding to lithium disilicate using different self-etching and conventional ceramic primers after long-term aging.

OBJECTIVES: To evaluate the bonding durability after artificial aging provided by a self-etching and a no-etching ceramic primer compared to primers, which are applied by the etch and rinse method. METHODS: Lithium disilicate blocks were bonded to a composite resin (Clearfill Core, Kuraray) using 5 bonding methods (N = 24). Specimens of group MEP were bonded using a self-etching primer and the corresponding luting resin (Monobond Etch&Prime/Variolink Esthetic, Ivoclar Vivadent) Specimens of group UBE were bonded using a two-bottle silane solution (Universal Primer/Estecem, Tokuyama) without hydrofluoric acid ceramic etching. Specimens of the other 3 groups were bonded using etch and rinse bonding systems with prior hydrofluoric acid ceramic etching (MPV: Monobond Plus/Variolink Esthetic, Ivoclar Vivadent; SUR: Scotchbond Universal/RelyX Ultimate, 3 M; GML: G-Multi Primer/G-CEM LinkForce, GC). Each group was divided into 3 subgroups (n = 8) according to the storage conditions (3 days water storage (37 °C), 30 days water storage, 7,500 thermal cycles (5-55 °C) and 150 days water storage, 37,500 thermal cycles). The tensile bond strength (TBS) was measured and the data was statistically analyzed. RESULTS: After 3 days the median TBS ranged from 14.6 to 41.7 MPa, after 30 days from 4.2 to 39.0 MPa and after 150 days from 0 to 29.7 MPa. Both bonding systems utilizing a self-etching primer showed a significantly lower TBS than group MPV using a conventional ceramic bonding system. SIGNIFICANCE: Especially after long-term storage with additional thermal cycling the bonding systems using primers without hydrofluoric acid ceramic etching do not provide a high bond strength.

Etching Patterns of Self-Etching Primers in Relation to Shear Bond Strength on Unground Enamel Samples.

It was the intention of the study to evaluate the etching effects of several self-etching primers on unground enamel and their relevance for shear bond strength testing. Seven self-etching primers (Clearfil SE, Futurabond NR, M-Bond, One Coat, Optibond, Transbond SEP+, Xeno III) and a conventional 35% phosphoric gel acid were applied to bovine incisors according to the manufacturer's instructions. All specimens were analyzed by electron microscopy. A visual four-step grading was used for the characterization of the macroscopic (5000×) and microscopic (20,000×) etching patterns. In addition, shear bond strength for all the products was tested with an Instron 3344 after 1000 thermocycles between 5 °C and 55 °C. Statistical analysis was carried out using Kruskal-Wallis with Dunn's post-test and Pearson's correlation coefficient. Very strong etching patterns with well-defined prisms were found for the conventional etching, Transbond SEP+, and to a lesser degree, for Xeno III. Clearfil SE and Futurabond NR revealed moderate etching patterns, and M-Bond, One Coat, and Optibond revealed very weak etching patterns. The bond strength correlated well with the etching patterns. The highest shear strength was obtained with conventional etching and Transbond SEP+, followed by Clearfil SE. Moderate shear bond strengths were found for Xeno III, Futurabond NR, One Coat, and M-Bond, and the lowest were found with Optibond.

Effects of Surface Treatment Procedures on Bond Strength of Lithium Disilicate Glass Ceramic.

OBJECTIVE: To evaluate the microshear bond strength (µSBS) of resin cement to a lithium disilicate glass ceramic conditioned with different surface treatment procedures. METHODS: Crystallised slices of lithium disilicate glass ceramic were randomly divided into five groups (n = 10) according to different surface treatment procedures: the no surface treatment (NT) group was untreated; the hydrofluoric acid (HF) group was conditioned with 4.5% HF; the silane (S) group was conditioned with a silane coupling agent; the hydrofluoric acid and silane (HFS) group was conditioned with HF followed by the silane coupling agent; and the Monobond Etch & Prime (MEP) (Ivoclar Vivadent, Schaan, Liechtenstein) group was conditioned with the one-step self-etching primer MEP. Resin cement was applied to the ceramic surfaces and irradiated. A µSBS test was performed. Failure analysis, surface roughness tests, surface topography examination and elemental analysis were also conducted. The data were analysed with a one-way analysis of variance (ANOVA) and Tukey honestly significant difference test (P < 0.05). RESULTS: The MEP group resulted in comparable µSBS to the HFS group (16.9 ± 4.3 MPa and 16.0 ± 2.2 MPa, respectively), but a significantly higher µSBS than the NT (1.0 ± 0.9 MPa), HF (8.9 ± 3.9 MPa) and S (12.6 ± 2.5 MPa) groups. Adhesive failure was mainly observed in the NT and HF groups, while the S, HFS and MEP groups demonstrated the most mixed failure. Though micrographs revealed a roughened surface in the HF group, no significant difference was found with any other groups. CONCLUSION: Within the limitations of this study, it can be concluded that the µSBS of resin cement to lithium disilicate glass ceramic etched with MEP is as efficient as that treated with HF and silane.

Effects of enamel deproteinization with different application times on the shear bond strength of a self-etching primer: An in vitro study.

OBJECTIVE: The aim of this in vitro study was to evaluate the effects of enamel deproteinization on the shear bond strength of a self-etching primer Transbond Plus™(TBP), with different application times of sodium hypochlorite (NaOCl 5.25%), primarily and secondarily on the adhesive remnant index score. MATERIALS AND METHODS: One hundred twenty-five freshly extracted human premolars were randomly and blindly divided into five groups according to the enamel surface preparation, as follows (n=25): group 1(control): Etching with 37% phosphoric acid for 15seconds+Bonding; group 2 (control): TBP™ without NaOCl, group 3: 60seconds NaOCl+TBP™, group 4: 30seconds NaOCl+TBP™, group 5: 15seconds NaOCl+TBP™. The same composite resin was used (Transbond XT™) to bond the orthodontic metal brackets. After the immersion of the teeth in distilled water at 37°C for 24hours the shear bond strength was measured using the universal testing machine and the adhesive remnant index score (ARI) was evaluated under an optical microscope (25×). RESULTS: The mean SBS values (inMPa) of the groups were respectively: group 1: 13.03±5.36; group 2: 12.28±3.06; group 3: 12.38±4.55; group 4: 12.98±5.76; and group 5: 11.73±5.67. Enamel deproteinization increased the SBS for groups 3 and 4, but no statistically significant difference was found between the five groups (P=0.883). Group 1 showed the highest ARI scores, with 52% of the teeth retaining all the adhesive (score 3). However, for all the other groups, scores 0 and 1 were predominant, with less than half of the adhesive or no adhesive at all remaining on the teeth. CONCLUSIONS: Enamel deproteinization with sodium hypochlorite (5.25%) and the variation of its application time has no effect on the SBS of the self-etching primer Transbond Plus ™.

Evaluation of Microleakage in Resin Composites Bonded to an Er:YAG Laser and Bur-Prepared Root and Coronal Dentin Using Different Bonding Agents.

Introduction: This study was conducted to assess the microleakage in Er:YAG laser-ablated and bur-prepared root and coronal dentin cavities using self-etch and total-etch adhesive systems. Methods: Sixty extracted caries-free human third molars were sectioned for dentin exposure. Then, two standard class V cavities were prepared in the root and coronal dentin of each tooth and allocated to one of the following conditioning groups randomly (n=12/Group): G1: Diamond bur for cavity preparation and single bond (BESB) etch-and-rinse adhesive for bonding, G2: Er:YAG laser (160 mJ, 20 Hz, 29.88 J/cm2) and SB (LESB), G3: Er:YAG laser and SB without acid etching (LSB), G4: Diamond bur and Clearfil SE Bond (BCSE) self-etch system, and G5: Er:YAG laser and Clearfil SE Bond (LCSE). The cavities were filled with Z100 composite resin. Dye penetration was assessed after thermocycling. Data analysis was done by Kruskal-Wallis and Mann-Whitney U tests. Statistical significance was set at P<0.05. Results: The results showed there were no statistically significant differences in microleakage between the two preparation methods (bur and laser) or the bonding agents applied (P>0.05). Regardless of the cavity preparation method, dye penetration was significantly higher in coronal dentin than in root dentin (P<0.05). Conclusion: The Er:YAG laser had the same efficacy as the conventional method for cavity preparation, and microleakage did not depend on the bonding agent. Microleakage was significantly higher in coronal restorations than in root restorations.

Influence of bonding surface and bonding methods on the fracture resistance and survival rate of full-coverage occlusal veneers made from lithium disilicate ceramic after cyclic loading.

OBJECTIVES: The purpose of this laboratory study was to evaluate the influence of bonding method and type of dental bonding surface on fracture resistance and survival rate of resin bonded occlusal veneers made from lithium disilicate ceramic after cyclic loading. METHODS: Fourty-eight extracted molars were divided into three groups (N=16) depending on the preparation: within enamel, within dentin/enamel or within enamel/composite resin filling. Lithium disilicate occlussal veneers were fabricated with a fissure-cusp thickness of 0.3-0.6mm. Restorations were etched (5% HF), silanated and adhesively luted using a dual-curing luting composite resin. Test groups were divided into two subgroups, one using a only a self-etching primer, the other additionally etching the enamel with phosphoric acid. After water storage (37°C; 21d) and thermocycling (7500 cycles; 5-55°C), specimens were subjected to dynamic loading in a chewing simulator (600,000 cycles; 10kg/2Hz). Surviving specimens were loaded until fracture using a universal testing machine. RESULTS: All specimens survived artificial aging, several specimens showed some damage. ANOVA revealed that enamel etching provided statistically significantly (p≤0.05) higher fracture resistance than self-etching when bonding to enamel and dentin. Self-etching provided statistically significant (p≤0.05) higher fracture resistance for the enamel-composite group than for the enamel group. Enamel etching provided statistically significant (p≤0.05) higher fracture resistance for the enamel and dentin group than for groups enamel and enamel-composite. SIGNIFICANCE: Etching enamel improved the fracture resistance of occlusal veneers when bonding to dentin and enamel and increased the survival rate when bonding to enamel.

Shear Bond Strength of Brackets Bonded with Self-Etching Primers Compared to Conventional Acid-Etch Technique: A Randomized Clinical Trial.

OBJECTIVES: The purpose of this randomized clinical trial (RCT) was to compare the shear bond strength (SBS) of orthodontic brackets bonded to enamel with conventional acid-etch (AE) technique and self-etching primers (SEP). MATERIALS AND METHODS: Twenty-two patients, requiring extraction of two bicuspids for orthodontic reasons, were recruited. In each individual, following blinding and allocation concealment, one intact premolar received conventional AE, whereas the contralateral premolar received SEP with a split-mouth design. Bonded brackets remained in the oral cavity for two months. Afterward, the teeth were extracted without debonding the brackets. SBS and adhesive remnant index (ARI) were measured using a Universal Instron machine and a stereomicroscope, respectively. RESULTS: The mean SBS of the conventional AE and SEP groups was 9.53 and 9.20 MPa, respectively. Paired t-test showed no statistically significant difference between the two groups (P=0.096). Comparison of ARI between the two groups, using Wilcoxon test, indicated that significantly less adhesive remained on enamel with brackets bonded with SEP compared to brackets bonded with conventional AE (P<0.001) although the SBS was higher in the AE group. CONCLUSION: The present study indicated that although there is no significant difference in SBS between SEP and conventional AE for bonding orthodontic metal brackets, the amount of residual adhesive on the enamel surface is significantly less with SEP than with conventional AE.(IRCT registration number: IRCT201705099086N3).

Microphotographic Assessment of Enamel Surface using Self-Etching Primer and Conventional Phosphoric Acid: An In vitro Study.

INTRODUCTION: Conventional acid-etching method irreversibly removes several microns of enamel surface and also involves many steps. Hence, a simplified technique that minimizes enamel loss, improves adhesion procedures, prevents saliva contamination, and saves chair time, thereby producing clinically useful bond strength, would be valuable. AIM: To assess and compare the bonding mechanism of a self-etching primer (SEP) to that of phosphoric acid on enamel of the human permanent teeth by a scanning electron microscope (SEM). MATERIALS AND METHODS: Thirty freshly extracted premolars were randomly divided into two groups of fifteen teeth each - the control group I (phosphoric acid) and experimental group II (self-etching primer). Brackets were bonded using Transbond XT adhesive on the buccal surfaces of the teeth after etching and priming according to their respective protocols. The teeth were then sectioned and the samples were subjected to a protocol of demineralization cycles. After complete dissolution of dental tissues, the specimens were gold sputter coated and evaluated under SEM. RESULTS: A characteristically uniform etch pattern was seen in the resin samples of the phosphoric acid/Transbond XT primer group, which revealed increased roughness and resin tags penetrating the demineralized enamel surface, whereas with Transbond Plus SEP, a regular resin tag distribution was observed which showed less magnitude when compared with the control group. CONCLUSION: From the study, it was concluded that Transbond Plus SEP produced an etch pattern which was more conservative than conventional phosphoric acid system.

Enamel shear bond strength of different primers combined with an orthodontic adhesive paste.

AIM: The aim of this study was a comparison of shear bond strength (SBS) on tooth enamel of different primers combined with the adhesive paste Transbond XT. MATERIALS AND METHODS: Forty bovine teeth were used in order to create 40 test blocks. The blocks were divided into four groups of 10 blocks each: group A - sample primer (SP); group B - Opal Seal (OS); group C - Transbond Plus SEP (TSEP); group D - Transbond XT Primer (TXT). After surface preparation and application of the primer, respectively, two stainless steel brackets were fixed on each tooth by using Transbond XT. Accordingly, 80 brackets were debonded (n=20). Shear bond strength and adhesive remnant index (ARI) scores were evaluated. Statistical analyses were performed by using the Student's t-test and Mann-Whitney U test. RESULTS: All tested groups revealed high shear bond strength in a similar size range. There were no significant differences between the groups concerning shear bond strength. The ARI scores of group C showed significantly lower ARI scores (0 and 1) than that of group D. Apart from that there was no statistical difference. CONCLUSION: In combination with the adhesive paste Transbond XT, all tested primers were suitable for fixing orthodontic brackets. The primers could be changed according to the clinical situation.

Shear bond strength of ceramic and metallic orthodontic brackets bonded with self-etching primer and conventional bonding adhesives.

INTRODUCTION: Adult patients typically require high-quality orthodontic treatment for ceramic brackets, but some clinicians remain concerned about the bond strength of these brackets. Therefore, the aim of this study was to determine the shear bond strength and de-bonding characteristics of metallic and ceramic brackets bonded with two types of bonding agents. METHODS: In an experimental study done in 2013 in Babol, Iran, 120 extracted human maxillary premolar teeth were randomly divided into four groups as follows: HM group: metallic bracket/conventional bonding agent; SM group: metallic bracket/Transbond self-etching primer; HC group: ceramic bracket/conventional bonding agent; SC group: ceramic bracket/Transbond self-etching primer. Twenty-four hours after thermocycling (1000 cycle, 5 °C-55 °C), the shear bond strength values were measured. The amount of resin remaining on the tooth surface (adhesive remnant index: ARI) was determined under a stereomicroscope. Enamel detachment index was evaluated under a scanning electron microscope. To perform statistical analysis, ANOVA, Kruskal-Wallis, and Tukey post-hoc tests were applied. The level of significance was set at p <0.05. RESULTS: The mean shear bond strength values (MPa ± SD) were group HM=12.59, group SM=11.15, group HC=7.7, and group SC=7.41. Bond strength differences between groups HM and SM (p=0.063) and between HC and SC (p=0.091) were not statistically significant. There were significant differences between HM and HC and between SM and SC groups (p < 0.05). Insignificant differences were found in ARI among all groups. CONCLUSION: Our findings indicated that the metallic brackets had higher bond strengths in comparison with ceramic brackets. In addition, self-etching primer was able to produce fewer bonds compared with the conventional technique. Many samples showed the bracket-adhesive interface failure or failure inside the adhesive.

The antibacterial activity and release of quaternary ammonium compounds in an orthodontic primer.

The aim of this study was to evaluate the impact of 10 wt% benzalkonium chloride (TB-BAC) or 10 wt% cetylpyridinium chloride (TB-CPC) on the antimicrobial properties of the orthodontic adhesive primer, Transbond XTT (TB). Antimicrobial activity was assessed using a zone of inhibition diffusion test and the release of the antimicrobial compounds was monitored by high performance liquid chromatography (HPLC). Shear bond strength (SBS) was tested using bovine enamel. Control, TB, specimens failed to demonstrate intrinsic antibacterial activity at 1, 7 and 14 days; whereas, TB-BAC and TB-CPC showed antibacterial effects at all times. HPLC analysis indicated no significant differences in the release behaviour of TB-BAC and TB-CPC (t-test, p > 0.05), except for the 7-day release which was higher for TB-BAC (p < 0.05). By 14 days the extents of release were 27 ± 2% and 25 ± 5% of the total initial loading for TB-BAC and TB-CPC, respectively. The incorporation of 10 wt% BAC or CPC in Transbond XTT adhesive primer also resulted in superior shear bond strength at 7 and 14 days (Fisher s LSD, p < 0.05) with no significant change in the mode ofbracket failure under shear stress (Pearson's chi-squared, p > 0.05).

El objetivo de este estudio fue evaluar el impacto del cloruro de benzalconio al 10% en peso del peso (TB-BAC) o de cloruro de cetilpiridinio al 10% del peso (TB-CPC) con propiedades antimicrobianas presentes en el adhesivo acondicionador ortodóncico, Transbond XT T (TB). La actividad antimicrobiana se evaluó usando una zona de prueba de difusión de inhibición y la liberación de los compuestos antimicrobianos se controló mediante cromatografía líquida de alta resolución (HPLC). La resistencia de adhesión al corte (SBS) se probó usando esmalte bovino. Las muestras control, TB no lograron demostrar actividad antibacteriana intrínseca a 1, 7 y 14 días; mientras que TB-BAC y TB-CPC mostraron efectos antibacterianos en todo momento. El análisis por HPLC no indicó diferencias significativas en el comportamiento de liberación de TB-BAC y TB-CPC (prueba t, p> 0,05), excepto en la liberación a los 7 días que fue más alta para TB-BAC (p <0,05). A los 14 días, los grados de liberación fueron de 27 ± 2% y de 25 ± 5% de la carga inicial total para TB-BAC y TB-CPC, respectivamente. La incorporación de 10% en peso de BAC o CPC en el imprimador adhesivo Transbond XT T también dio como resultado una resistencia superior corte a los 7 y 14 días (Fisher's LSD, p <0.05) sin cambios significativos en el modo de falla del bracket bajo tensión de corte (Pearson's chi-cuadrado, p> 0.05).

The antibacterial activity and release of quaternary ammonium compounds in an orthodontic primer

The aim of this study was to evaluate the impact of 10 wt% benzalkonium chloride (TBBAC) or 10 wt% cetylpyridinium chloride (TBCPC) on the antimicrobial properties of the orthodontic adhesive primer, Transbond XT™ (TB). Antimicrobial activity was assessed using a zone of inhibition diffusion test and the release of the antimicrobial compounds was monitored by high performance liquid chromatography (HPLC). Shear bond strength (SBS) was tested using bovine enamel. Control, TB, specimens failed to demonstrate intrinsic antibacterial activity at 1, 7 and 14 days; whereas, TBBAC and TBCPC showed antibacterial effects at all times. HPLC analysis indicated no significant differences in the release behaviour of TBBAC and TBCPC (ttest, p > 0.05), except for the 7day release which was higher for TBBAC (p < 0.05). By 14 days the extents of release were 27 ± 2% and 25 ± 5% of the total initial loading for TBBAC and TBCPC, respectively. The incorporation of 10 wt% BAC or CPC in Transbond XT™ adhesive primer also resulted in superior shear bond strength at 7 and 14 days (Fisher's LSD, p < 0.05) with no significant change in the mode of bracket failure under shear stress (Pearson's chisquared, p > 0.05) (AU)

El objetivo de este estudio fue evaluar el impacto del cloruro de benzalconio al 10% en peso del peso (TBBAC) o de cloruro de cetilpiridinio al 10% del peso (TBCPC) con propiedades antimicrobianas presentes en el adhesivo acondicionador ortodóncico, Transbond XT ™ (TB). La actividad antimi crobiana se evaluó usando una zona de prueba de difusión de inhibición y la liberación de los compuestos antimicrobianos se controló mediante cromatografía líquida de alta resolución (HPLC). La resistencia de adhesión al corte (SBS) se probó usando esmalte bovino. Las muestras control, TB no lograron demostrar actividad antibacteriana intrínseca a 1, 7 y 14 días; mientras que TBBAC y TBCPC mostraron efectos antibac terianos en todo momento. El análisis por HPLC no indicó diferencias significativas en el comportamiento de liberación de TBBAC y TBCPC (prueba t, p> 0,05), excepto en la liberación a los 7 días que fue más alta para TBBAC (p <0,05). A los 14 días, los grados de liberación fueron de 27 ± 2% y de 25 ± 5% de la carga inicial total para TBBAC y TBCPC, respectivamente. La incorpora ción de 10% en peso de BAC o CPC en el imprimador adhesivo Transbond XT ™ también dio como resultado una resistencia superior corte a los 7 y 14 días (Fisher's LSD, p <0.05) sin cambios significativos en el modo de falla del bracket bajo tensión de corte (Pearson's chicuadrado, p> 0.05) (AU)

Immediate and Delayed Effects of Diode Laser on Debonding of Ceramic Brackets: An in vitro Study.

AIM: The aim of the study is to evaluate the immediate and delayed effects of diode laser on debonding of ceramic brackets. MATERIALS AND METHODS: A total of 60 human extracted premolar teeth were randomly assigned to three different treatment groups. All teeth were bonded with adhesive precoated (APC) ceramic brackets (3M Unitek). A total of 20 teeth were debonded without lasing (group 1), 20 immediately after lasing (group 2), and 20 1 hour after lasing (group 3). For the lasing groups (groups 2 and 3), access cavity was prepared on the occlusal surface to a 2 mm diameter. A transbond plus self-etching primer (3M Unitek, Monrovia, CA, USA) and APC PLUS clarity advanced brackets (3M, Unitek, Monrovia, CA, USA) were used. The shear bond strength (SBS) and adhesive remnant index (ARI) were measured. The internal pulpal wall temperature was noted for the laser groups. RESULTS: The mean SBS was 15.4, 11.57, and 11.79 MPa for groups 1 to 3 respectively. Post hoc test showed significant difference (p < 0.001) between the control group and the lased groups. For groups 2 and 3, the rise in temperature was at an average of 1.4 and 1.3°C respectively. CONCLUSION: The SBS of APC brackets decreased by 33.3% on application of diode laser without increasing the internal pulp chamber wall temperature significantly. Shear bond strength remains more or less the same whether debonding is done immediately after lasing or 1 hour after lasing. Diode lasers increased the ARI scores and thus decreased the risk of enamel fracture.

Comparison of the efficacy of a conventional primer and a self-etching primer.

INTRODUCTION: In orthodontic practice, the bonding protocol makes use of a primer between the bracket and the enamel surface to create a reliable bond. In order to optimize the technique and reduce bonding time, a new group of primers has been introduced in orthodontics: the self-etching primers (SEP). The aim of this work was to compare their efficacy with that of a traditional primer. MATERIALS AND METHOD: This study is a single-center, single-blind, clinical trial using the SEP system on teeth 14 and 25 and the Ortho-Solo(®) system (traditional hydrophilic primer) on teeth 24 and 15 in the same patient. The study population was composed of 100 patients treated in a private orthodontic office in Casablanca. Recruitment for this sample included all patients treated orthodontically without extractions, possessing teeth that were considered healthy, with no occlusal interferences; on the other hand, all patients with mental or physical disabilities, those aged under 14 and those with poor orodental hygiene were excluded from the study. The Kaplan-Meier test was used to compare results. RESULTS: The bond failure rates for the two groups were 7.5% in the SEP group and 9% in the Ortho-Solo(®) group. The difference between these two adhesive systems was not statistically significant (P=0.34). Concerning the type of bond failure, the comparison again shows no statistically significant difference (P=0.44). In both systems, cohesive failures concerned only 2% of all the brackets bonded. DISCUSSION: The clinical trial was performed with a crossover design to avoid bias due to chewing patterns, a factor that is responsible for most of the failures noted in the study. The results of the studies by Miller and Buyukyilmaz, and some others, are in agreement with our results. However other in vivo and in vitro studies contradict our results, showing higher bond failure rates with the self-etching system. CONCLUSION: SEP is as effective as a traditional hydrophilic adhesive and, in addition, possesses advantages in terms of ergonomics and chair-time. The literature confirms the data of this clinical trial and recommends the use of SEP; the only remaining limitation is its high cost.

Comparison of Shear Bond Strength of New Self-etching Primer with Conventional Self-etching Primers: An In-vitro Study.

BACKGROUND: In the past few years, there has been a major research drive to increase bond strength between dental materials and dental hard tissue and to reduce the associated demineralization around fixed orthodontic appliances. Thus, a recent approach is to incorporate an antibacterial agent into the primer to reduce the demineralization and enhance bond strength. The objective of this study was: (1) To evaluate the shear bond strength of orthodontic preadjusted edgewise appliance brackets bonded to extracted premolar teeth with antimicrobial self-etch primer (Reliance self-etching primer, Clearfil Protect Bond) and self-etching primer without antimicrobial agent (Clearfil SE bond). (2) To compare the mean shear bond strength values of the tested materials to conventional self-etching primer Transbond Plus. MATERIALS AND METHODS: A total of 125 extracted human premolar teeth were randomly divided into five groups of 25 teeth each. Each sample was embedded in an acrylic block of polymethyl meth acrylate resin till coronal portion. Instron testing machine model LR LOYD 50 K was used for testing the shear bond strength of individual samples. RESULTS: The results of the study showed that all five groups had adequate clinically acceptable bond strength. In intergroup comparison, there was statistically significant difference in bond strength of Reliance self-etching primer, Promt L pop, Clearfil Protect Bond, clearfil SE bond and Transbond Plus. CONCLUSION: Reliance self-etching primer showed highest bond strength, followed by Clearfil Protect Bond, clearfil SE bond, and Transbond Plus. Clearfil Protect Bond primer containing methacryloxy dodecyl pyridium bromide have been demonstrated to kill Streptococcus mutans within a short time of contact and also exhibits an inhibitory effect on the growth of bacteria on its surface.

Influence of restoration thickness and dental bonding surface on the fracture resistance of full-coverage occlusal veneers made from lithium disilicate ceramic.

OBJECTIVES: The purpose of this in-vitro study was to evaluate the influence of ceramic thickness and type of dental bonding surface on the fracture resistance of non-retentive full-coverage adhesively retained occlusal veneers made from lithium disilicate ceramic. METHODS: Seventy-two extracted molars were divided into three test groups (N=24) depending on the location of the occlusal veneer preparation: solely within enamel, within enamel and dentin or within enamel and an occlusal composite resin filling. For each test group, occlusal all-ceramic restorations were fabricated from lithium disilicate ceramic blocks (IPS e.max CAD) in three subgroups with different thicknesses ranging from 0.3 to 0.7mm in the fissures and from 0.6 to 1.0mm at the cusps. The veneers were etched (5% HF), silanated and adhesively luted using a self etching primer and a composite luting resin (Multilink Primer A/B and Multilink Automix). After water storage at 37°C for 3 days and thermal cycling for 7500 cycles at 5-55°C, specimens were subjected to dynamic loading in a chewing simulator with 600,000 loading cycles at 10kg combined with thermal cycling. Unfractured specimens were loaded until fracture using a universal testing machine. Statistical analysis was performed using Kruskal-Wallis and Wilcoxon tests with Bonferroni-Holm correction for multiple testing. RESULTS: Only specimens in the group with the thickest dimension (0.7mm in fissure, 1.0mm at cusp) survived cyclic loading without any damage. Survival rates in the remaining subgroups ranged from 50 to 100% for surviving with some damage and from 12.5 to 75% for surviving without any damage. Medians of final fracture resistance ranged from 610 to 3390N. In groups with smaller ceramic thickness, luting to dentin or composite provided statistically significant (p≤0.05) higher fracture resistance than luting to enamel only. The thickness of the occlual ceramic veneers had a statistically significant (p≤0.05) influence on fracture resistance. SIGNIFICANCE: The results suggest to use a thickness of 0.7-1mm for non-retentive full-coverage adhesively retained occlusal lithium disilicate ceramic restorations.

Retention of sealants during orthodontic treatment: an in vitro comparison of two etching protocols.

OBJECTIVE: To test the retention of smooth-surface sealants bonded with different etching protocols against toothbrushing and, secondarily, to characterize the type and location of sealant loss. MATERIALS AND METHODS: Eighty-nine extracted human teeth were randomly assigned one of two etching protocols: 37% phosphoric acid etch (ETCH) or self-etching primer (SEP). Six specimens at a time were placed in a toothbrushing machine to simulate 4, 8, 12, and 24 months of toothbrush abrasion. Using black-light photographs of each specimen taken before and after brushing, four blinded coinvestigators determined new sealant loss, loss along the edge of an initial defect, and the location of sealant loss. RESULTS: Overall, there were significantly (P < .05) more teeth with sealant loss in the SEP group (38.6%) than in the ETCH group (15.5%). New loss of sealant was significantly (P < .05) more likely in the SEP group (27.2%) than in the ETCH group (2.2%). Of the teeth with new loss of sealant, all (100%) had loss at the edge, and 23% had progressive loss. There was no significant group difference in sealant loss from initial defects. Of the teeth that showed enlargement of initial defects, 91% had loss at the edge and 91% had progressive loss. CONCLUSIONS: Using SEP to apply facial sealants results in lower retention rates than using ETCH. The vast majority of sealant loss occurs at the edges. Loss of sealant due to enlargement of an initial defect is highly progressive over time.