Enamel deproteinization before acid etching and its effect on the shear bond strength--an in vitro study

Comparative evaluation of shear bond strength and penetration of self-etch sealant with and without enamel deproteinization: an in vitro study

AIM

To compare the shear bond strength and penetration ability of self-etch sealant with and without enamel deproteinization.

MATERIALS AND METHODS

A total of 37 sound extracted teeth were selected and 31 teeth were used for testing shear bond strength of self-etch sealant. For this, crowns portions of selected teeth were cut longitudinally with a diamond disc into a mesial and distal half, thereby yielding 62 samples. They were further divided into two groups; in Group 1, samples were deproteinised with 5.25% sodium hypochlorite and a sealant cylinder was built on the proximal surface. In Group 2, sealant cylinders were built without deproteinising the surface. Shear bond strength was tested using Universal Testing Machine. The remaining six teeth were used for penetration evaluation of self-etch sealant. In Group 1, the occlusal surface was deproteinised with 5.25% sodium hypochlorite and self-etch sealant was directly applied. In Group 2, sealant was applied without deproteinisation. The samples obtained after sectioning were observed under scanning electron microscope for sealant penetration. Mann-Whitney test and Chi-square analysis were utilised for statistical analysis.

RESULTS

The results showed that the shear bond strength of the two groups was statistically not significant (p = 0.23). However, the comparison of % penetration revealed a statistically significant difference between the groups (p = 0.016).

CONCLUSION

Deproteinising the enamel surface prior to application of self-etch sealant enhanced the penetration ability of the sealant but did not show any effect on shear bond strength.

Effects of fluorosed enamel on orthodontic bracket bonding : An in vitro study

OBJECTIVE

To investigate the effect of enamel deproteinization and air abrasion on shear bond strength (SBS), adhesive remnant index (ARI) scores, and surface topography when bonding orthodontic brackets to fluorosed enamel.

MATERIALS AND METHODS

The sample included 90 fluorosed and 30 normal premolars divided into four groups: group I (fluorosed premolars subjected to air abrasion before acid etching), group II (fluorosed premolars subjected to deproteinization before acid etching), group III (fluorosed premolars; control for groups I and II), and group IV (normal premolars; control for group III). Bonding procedures included etching with 37% phosphoric acid, priming with TransbondTM XT primer (3M Unitek, Monrovia, CA, USA), and application of TransbondTM XT adhesive paste (composite; 3M Unitek, Monrovia, CA, USA). Air abrasion was done using 50 µm aluminum oxide particles under 0.28 MPa pressure for 5 s with the micro-etcher held at a distance of 10 mm. Deproteinization was done for 60 s with 5% sodium hypochlorite (NaOCl).

RESULTS

Fluorosed premolars subjected to deproteinization showed the lowest (median = 6.57 MPa) SBS among the four groups, followed by 8.14, 8.90, 8.14 MPa for groups I, III, and IV respectively. ARI scores were significantly different between the four groups (p = 0.006). Fluorosed enamel etched after air abrasion or deproteinization with NaOCl showed a predominance of type 4 etching pattern with some areas appearing unetched.

CONCLUSIONS

Shear bond strength of all groups was within the 6-8 MPa acceptable range for orthodontic purposes. Fluorosed premolars subjected to deproteinization showed the lowest values. Further studies are recommended to scrutinize the deproteinization technique.

Effectiveness of sodium hypochlorite treatment on the bonding of four adhesive systems to fluorotic enamel

The study evaluated the effect of sodium hypochlorite (NaOCl) treatment on fluorotic enamel bonding of four adhesive systems. They were Single Bond 2 (SB2), Prime&Bond NT (PBN), Clearfil SE Bond (CSB), and Single Bond Universal (SBU). One hundred eighteen extracted moderate fluorotic molars were divided into eight groups according to NaOCl pretreatment and four adhesive systems. The microshear bond strength (μSBS), etching pattern, and penetration depth (PD) were observed. The statistical method was two-way ANOVA and least significant difference (LSD) test (α=0.05). The application of NaOCl significantly increased the μSBS of PBN and SBU (p<0.05). The enamel-etching pattern of CSB and SBU was deeper under SEM. A noticeable increase of PD was in SB2 and SBU after the application of NaOCl (p<0.05). Pretreatment of 5.25% NaOCl for the 60 s can increase μSBS of PBN and SBU, PD of SB2 and SBU, and improve enamel-etching pattern of CSB and SBU to fluorotic enamel.

Penetration and Adaptation of the Highly Viscous Zinc-Reinforced Glass Ionomer Cement on Contaminated Fissures: An In Vitro Study with SEM Analysis

Objective: To evaluate the penetration and adaptation of highly viscous zinc-reinforced glass ionomer cement (ZRGIC), using a scanning electron microscope (SEM), when applied under various contaminated conditions on grooves and fissures of primary second molars. Materials and Methods: A total of 40 extracted human primary second molars were randomly assigned into five groups (8 teeth each), with different surface conditions (conditioned with 40% polyacrylic acid, dry condition, water contamination, saliva contamination, or saliva contamination and air-drying) on the occlusal surface before placement of zinc-reinforced highly viscous glass ionomer cement with the finger-press technique. After sectioning the teeth, they were subjected to SEM analysis, where four in each group underwent aging by thermocycling and the other four were without aging. ANOVA tests, post hoc analysis, and unpaired t-tests were used for statistical analyses. Results: There was a significant statistical difference in the sealant penetration in the non-aging group, but in the aging group, there was no significant statistical difference in the sealant penetration. On other hand, a significant statistical difference was found in the adaptation between all the groups (p < 0.05). Highly viscous zinc-reinforced glass ionomer fissure sealants have better fissure penetration and more intimate adaptation under fissures conditioned with 40% polyacrylic acid and dry surface fissures with no contamination. However, the best penetration and retention after aging were under contaminated fissures with a shiny layer of saliva. Conclusions: The ZRGIC is a highly viscous fluoride-releasing cement, effectively seals fissures by interfering with food lodgment and protecting teeth from caries. It is advisable to restore the fissures with the minimal technique of sensitive fluoride-releasing GIC, particularly in young, uncooperative children, rather than leaving a caries-prone environment.

Assessment of shear bond strength and microleakage of fissure sealant following enamel deproteinization: An in vitro study

BACKGROUND

To evaluate the effect of two different deproteinizing agents (5.25% sodium hypochlorite and Papacarie®) prior to acid etching on the shear bond strength and microleakage of a fissure sealant material.

MATERIAL AND METHODS

A total of 123 extracted noncarious human third molar teeth were randomly divided into three groups for each test: acid etching alone (control) (C), sodium hypochlorite (NaOCl), and Papacarie Duo® (PC). The shear bond strength tests were performed using a universal testing machine, and microleakage was evaluated using a dye penetration method.

RESULTS

The mean shear bond strength values obtained in Group C were significantly lower than those of Group NaOCl and Group PC (p=0.0001). There were no significant differences between Group NaOCl and Group PC (p>0.05). No statistically significant difference was observed among the groups in terms of microleakage (p>0.05).

CONCLUSIONS

Papacarie Duo® and 5.25% sodium hypochlorite treatments before etching increased the shear bond strength of the fissure sealant. However, pre-treatment with these agents did not decrease the microleakage between teeth and sealant. Key words:Deproteinization, microleakage, papain, dental seal, shear bond strength.

Effects of different deproteinizing agents on topographic features of enamel and shear bond strength - An in vitro study

OBJECTIVES:

To evaluate and compare the effect of different enamel deproteinizing agents on topographic features of enamel and shear bond strength before acid etching.

MATERIALS AND METHOD:

In total, 120 sound human maxillary premolars were taken and divided into three groups: Group 1 control (37% phosphoric acid (H₃PO₄), Group 2, (5.25% Sodium Hypochlorite (NaOCl)+ 37% H₃PO_4, and Group 3, (10% Papain gel + 37% H₃PO₄). These groups were further divided into A and B subgroups. In subgroups 1A, 2A, and 3A (n30) topographic features were evaluated using Scanning electron microscope (SEM) at different magnifications. Insub-groups 1B, 2B, and 3B (n90) metal brackets were bonded with Transbond™ XT, and all the samples were subjected for Shear Bond Strength (SBS) evaluation using universal testing machineat a cross speed of 0.5 mm²/min. The failure mode was analyzed using adhesive remnant index (ARI). Statistical analysis was done using one-way ANOVA for the shear bond strength, and Kruskal-Wallis test followed by Mann-Whitneywas performed for ARI scores.

RESULTS:

SEM showed predominance of type 3 etching pattern in control Group (1A) and type 1 and type 2 in deproteinizedGroups (2A and 3A). Mean values of shear bond strength showed statistically significant differences between evaluated groups (P < 0.005). The lowest and highest shear bond strength was attributed to Group 1B (Control) and 3B (10% papain gel), respectively. Statisticallysignificant differences were noted for the mean ARI scores between control and deproteinized group (P < 0.05).

CONCLUSION:

10% papain geland 5.25% NaOCl can be used as deproteinizing agents on enamel surface before acid etchingto enhance the shear bond strength of orthodontic brackets.

Etching Patterns of Sodium Hypochlorite Pretreated Hypocalcified Amelogenesis Imperfecta Primary Molars: SEM Study

Aim: To investigate the etching patterns of hypocalcified amelogenesis imperfecta (AI) in primary molars pretreated with 5.25% NaOCl prior to phosphoric acid application using scanning electron microscopy (SEM). Study design: Ten hypocalcified AI primary molars were collected, sectioned longitudinally into 2 parts and allocated into two groups of ten specimens each. The enamel surface in the first group (control group) was etched using 37% phosphoric acid gel for 15 seconds; while in the second group (study group), it was pretreated using 5.25 sodium hypochlorite(NaOCl) for 60 seconds prior to acid etching. Each specimen was examined at 16 different sites, and evaluated for the etching pattern (types I, II, and III) distribution using SEM. A total of 320 microphotographs at 1,500 magnification were obtained using Auto-Cad 2007 software. Results: The etching pattern with phosphoric acid was not uniform with predominance of type III etching (65.63%), while the pretreated enamel surfaces showed a significant increase in type I and II(82.5%) etching patterns (P<0.001). Conclusion: Treatment of primary teeth affected by hypocalcified AI using 5.25% NaOCl prior to phosphoric acid etching significantly improves the etching pattern which is required for good resin bonding.

Combined Effect of Enamel Deproteinization and Intermediate Bonding in the Retention of Pit and Fissure Sealants in Children: A Randomized Clinical Trial

OBJECTIVE

This manuscript shows if enamel deproteinization along with an intermediate layer of bonding enhances the retention of pit and fissure sealants..

STUDY DESIGN

Two hundred six mandibular first permanent molars were allocated to Group I (n=103) and Group II (n=103). Group I underwent deproteinization, acid etching, bonding agent application and pit & fissure sealant placement while Group II treated with acid etching followed by pit & fissure sealant application only. Clinical analysis of all the teeth in the two groups was performed at 1, 3, 6, 9 and 12 months respectively. Pearson's chi - square test was utilized to evaluate the success of both treatment procedures (p<0.05).

RESULTS

At 12 months follow up the differences between the groups pertaining to Marginal integrity, Marginal discoloration and Anatomical form were statistically significant suggesting enhanced retention in Group I.

CONCLUSIONS

Enamel deproteinization along with the use of intermediate bonding layer significantly enhances the retention of pit and fissure sealants in terms of enhanced marginal integrity, decreased marginal discoloration and preserving the anatomical form.

Effect of Enamel Deproteinization in Primary Teeth

OBJECTIVE

To evaluate and compare the topographical features of enamel surface, etched with different materials.

STUDY DESIGN

10 extracted human primary molars were randomly selected and cut and trimmed to 1 mm². Each group comprised of 10 blocks and the enamel was treated as follows: Group I-35% H₃PO_4; Group II-5.25% NaOCl + 35% H₃PO_{4 ;}Group III-5.25% NaOCl; Group IV no treatment was carried out. All the samples were prepared for Scanning electron microscope analysis. The images were obtained and evaluated for the quality type I-II etching of the enamel surface using Auto-CAD 2011 software.

STATISTICAL ANALYSIS USED

Wilcoxon Signed Ranks Test (p<0.001).

RESULTS

The mean surface area of type I and II etching pattern values for Group- I was 39608.18 μm² and Group- II was 45051.34 μm².

CONCLUSION

Deproteinization with 5.25% Sodium hypochlorite prior to acid etching could be used to increase the surface area of adhesion of composite material with the tooth surface.