Effects of contamination and mechanical disturbance on the quality of acid-etched enamel

Detection of pit and fissure sealant microleakage using quantitative light-induced fluorescence technology: an in vitro study

This in vitro study aimed to evaluate the feasibility of quantitative light-induced fluorescence (QLF) technology for detecting the presence and severity of microleakage of pit and fissure sealants. The areas of interest (AOIs) were 160 pits and fissures of 40 extracted permanent teeth. Fluorescent images were acquired using a QLF device, and the maximum fluorescence loss ΔFmax of each AOI was analyzed. After staining and cross-sectioning of the teeth, histological dye penetration was scored on a scale of 0 to 3. The relationship between ΔFmax and microleakage depth was analyzed, and the areas under the curve (AUCs) were calculated. The │ΔFmax│ increased as microleakage depth increased. The ΔFmax values of microleakage areas showed a strong significant correlation with the histological scores of dye penetration (r = - 0.72, P = 0.001). AUC analysis showed a high diagnostic accuracy for microleakage depth (AUC = 0.83-0.91). The highest AUC of 0.91 was found when differentiating the outer half microleakage of the sealant (histological score 0 vs. 1-3). QLF technology is effective in assessing the presence and severity of microleakage, suggesting its potential for noninvasive detection and monitoring of sealant microleakage in clinical settings.

In Vitro Evaluation of Viscosity, Depth of Penetration, Microleakage, and Shear Bond Strength of Conventional and Hydrophilic Sealants

Background

Sealants are effective in preventing and arresting pit and fissure caries. Newer brands of sealants continue to be developed despite the lack of scientifically based information addressing the caries-preventive properties of these materials. Hence, laboratory in vitro tests play a vital role in providing the necessary information regarding the efficacy of new products in a short period of time.

Objectives

To compare and evaluate the viscosity, resin tag length, microleakage, and shear bond strength between conventional and hydrophilic sealants.

Materials and methods

A total of 40 extracted third molars were selected. Only 20 were evaluated for microleakage and resin tag length and another 20 for shear bond strength evaluation between group I-ClinPro and group II-UltraSeal XT hydro. After sealant placement, specimens were immersed in 0.1% rhodamine dye, followed by thermocycling. Microleakage testing was done using a confocal laser scanning microscope and resin tag length evaluation using a scanning electron microscope (SEM) and shear bond strength using an Universal Instron machine. Viscosity was assessed using an Anton Paar viscometer. Results were subjected to statistical analysis using Statistical Package for the Social Sciences (SPSS) software version 20.

Results

Viscosity and mean microleakage scores for group I (0.92 MPa and 1.50) were found to be higher than for group II (0.72 MPa and 0.60). Mean resin tag length and mean shear bond strength for group I (7.46 ± 0.95 μm and 13.71 ± 0.94 MPa) were found to be less compared to group II (10.03 ± 1.00 μm and 20.39 ± 0.98 MPa). The results were found to be statistically significant (p < 0.05).

Conclusion

Group II was found to be less viscous, which resulted in the formation of resin tags of sufficient length and showed less microleakage and higher shear bond strength than group I.

How to cite this article

Prabakar J, Jeevanandan G, Kengadaran S. In Vitro Evaluation of Viscosity, Depth of Penetration, Microleakage, and Shear Bond Strength of Conventional and Hydrophilic Sealants. Int J Clin Pediatr Dent 2023;16(5):745-750.

Shear Bond Strength and Microleakage of Pit and Fissure Sealants Placed after Saliva-Contaminated Etched Enamel

Saliva contamination of etched enamel before sealant application is the most common reason for failure of fissure sealants, thus affecting the effect of caries prevention. This study aimed to evaluate the shear bond strength (SBS) and microleakage of resin-based fissure sealant on saliva-contaminated etched enamel after rinsing, re-etching, and applying universal adhesive. Fifty human third molars were sectioned into 2 parts and embedded in acrylic resin to obtained 100 samples. The samples were randomly assigned to 5 groups: 1, etching; 2, etching + contamination; 3, etching + contamination + rinsing; 4, etching + contamination+ re-etching; 5, etching + contamination + universal adhesive. Each group was divided into 2 subgroups: 24 h storage and 5000× thermocycling. After measuring SBS, failure mode was analyzed. In an additional 15 teeth, microleakage was tested using dye penetration method. Three more teeth were used for scanning electron microscope (SEM) observation of the enamel surface morphology in each group. The adhesive group had significantly higher mean SBS after 24 h storage, while the re-etching group were better after 5000× thermocycling. The etching, etching+ contamination+ re-etching, and etching+ contamination+ universal adhesive groups showed the least microleakage. The SEM reveals considerable variations in the enamel surface appearance within groups. Re-etching or applying universal adhesive in saliva-contaminated etched enamel before sealant can achieve satisfactory results. Considering the less operative steps and the shorter chair time, applying universal adhesive is more recommended for a pediatric patient if saliva-contamination happened before sealant application.

An In vitro shear bond strength study to evaluate the efficacy of moisture-insensitive primer

Aims:

We aimed to evaluate and compare the efficacy of moisture-insensitive primer (MIP) Transbond MIP while bonding to wet enamel surface.

Materials and Methods:

This study was done on 100 freshly extracted human premolar teeth, collected from the Department of Oral Surgery, Government Dental College, Calicut. They were stored in distilled water at room temperature. All teeth were healthy and without caries lesion, no evidence of surface defects, or any developmental morphological aberrations. Teeth were divided into 5 groups of twenty each for the testing and Brackets were bonded onto the tooth surface in 5 different bonding sequences using Transbond XT and Transbond MIP..

Results:

All the three groups of MIP have gained statistically significant higher SBS compared to Group I (Transbond XT primer in wet). Marked decrease in SBS of Transbond XT resin in wet environment was deduced. MIP in repriming sequence (Group IV) is found to have higher bond strength than other MIP groups.

Conclusions:

Clinical acceptability of Transbond MIP in wet environment could be recommended. MIP repriming should be done in cases where there is a doubt of contamination with saliva after initial primer application.

Efficacy of hydrophilic resin-based sealant: A systematic review and meta-analysis

OBJECTIVES

This meta-analysis review aims to answer two questions: 1) What is the effectiveness of hydrophilic resin-based sealant (RBS) in preventing/arresting pits and fissures caries in permanent teeth, and 2) What is the retention rate of a hydrophilic RBS as compared to alternative treatments.

DATA

Randomized control trials investigating the efficacy of hydrophilic RBS compared to any other (placebo) treatment for permanent teeth. Outcomes were retention rate and caries prevention/arresting.

SOURCES

A systematic search for eligible studies was conducted on six electronic databases (Scopus, Ovid MEDLINE, Ovid Embase, Cochrane; Web of Science, PubMed) from inception to March 2021. The Cochrane guidelines were used to classify the risk of bias.

STUDY SELECTION/RESULTS

A systematic literature search resulted in 290 studies. Thirteen articles met our inclusion criteria and were included in the systematic review. Six articles were identified as good or fair quality and were included in the quantitative analysis. Meta-analysis results indicated that there is no significant difference in retention (RR 1.01, 95% CI:0.96-1.07, P-value 0.66), (RR 1.03, 95% CI: 0.89-1.19, P-value 0.0009) at six and twelve months, respectively. Likewise, for caries prevention there is no significant difference (RR 0.97, 95% CI: 0.91-1.03, P-value 0.19), (RR 0.30, 95% CI: 0.91-1.03, P-value 0.30) at six and twelve months.

CONCLUSIONS

This meta-analysis showed no statistically significant difference between the hydrophilic RBS and alternative treatment options (such as conventional resin or glass ionomer) regarding retention or caries prevention at six- and twelve-month follow-up. Future studies are required to investigate longer-term outcomes.

Microleakage Assessment of Two Different Pit and Fissure Sealants: A Comparative Confocal Laser Scanning Microscopy Study

Introduction

Pit and fissures of permanent dentition are considered to be highly vulnerable to the adhesion of cariogenic microorganisms and consequently result in caries formation. The main problem associated with sealant failure will be microleakage. Therefore, sealants can be considered to be an effective preventive procedure for dental caries, only if it strongly bonds to the tooth, and protect the pit and fissures from the oral bacterial environment.

Aim and objective

To compare and assess the microleakage of two different pit and fissure sealants on permanent molars.

Materials and methods

A total of 20 extracted third molars were randomly divided into two groups where group I is conventional sealant and group II is hydrophilic sealant. Occlusal surfaces of permanent molars were treated with 37% orthophosphoric acid before sealant placement. Tooth samples were subjected to 0.1% rhodamine dye immersion, thermocycling, and tooth samples were sectioned and evaluated under a confocal laser microscope for dye penetration. A non-parametric test (Mann–Whitney U) was performed to compare the mean microleakage score difference between the groups.

Results

Group II (hydrophilic sealant) showed a minimum level of the microleakage score when compared to group I (conventional sealant) and was found to be statistically significant using the Mann-Whitney U test with a p value <0.05.

Conclusion

The less the microleakage, the better will be the retention of the sealant for a longer duration and cariostatic action.

How to cite this article

Prabakar J, Indiran MA, Kumar P, et al. Microleakage Assessment of Two Different Pit and Fissure Sealants: A Comparative Confocal Laser Scanning Microscopy Study. Int J Clin Pediatr Dent 2020;13(S-1):S29–S33.

Evaluation of shear bond strength of orthodontic molar tubes bonded using hydrophilic primers: An in vitro study

OBJECTIVE

To evaluate and compare the shear bond strength (SBS) of orthodontic molar tubes bonded using two hydrophilic primers along with a moisture tolerant adhesive system to dry and saliva-contaminated enamel surfaces; and to assess the mode of their bond failure.

MATERIALS AND METHODS

A total of 60 extracted human mandibular molars were randomly divided into three major groups according to the primer used, each consisting of 20 molars: XT group acts as a control and bonded with the conventional hydrophobic Transbond XT primer, OS group bonded with the hydrophilic Ortho Solo primer, AP group bonded with the hydrophilic Assure Plus all surface bonding resin. Each major group was further divided into two subgroups, of 10 molars each, according to presence or absence of saliva. All the specimens were thermocycled 500 cycles between 5̊ and 55°C. Shear forces were applied to the specimens with a universal testing machine at a crosshead speed of 1mm/min and SBS was measured in megapascals (MPa). The mode of failure was determined using the adhesive remnant index (ARI). Data were analysed using two-way analysis of variance (ANOVA) followed by univariate analysis and Bonferroni post hoc tests.

RESULTS

The three tested primers did not show a significant difference in the mean SBS in dry conditions (P=0.137); the mean SBS of OS and AP primers were 15.60±5.879MPa and 12.51±2.583MPa respectively which were comparable to that of the hydrophobic XT primer (12.76±2.952MPa). In saliva-contaminated conditions, the mean SBS values were 10.41±4.457MPa and 9.22±3.422MPa for OS and AP primers respectively, which were significantly higher than that of XT primer (4.82±2.050MPa) (P=0.004). When comparing the mean SBS for each group according to the bonding condition, it was significantly higher in dry bonding compared to saliva-contaminated bonding for the three primers; XT (P<0.001), OS (P=0.003) and AP (P=0.011). In the dry field, most of the bond failures of the three primers were adhesive (score 3), whereas in the saliva-contaminated field, most of the failures were cohesive (score 1).

CONCLUSION

Dry bonding yielded the highest SBS for the three primers. Saliva contamination significantly decreased the bond strength of both hydrophilic primers; however, the values were above the clinically acceptable limit. The hydrophilic primers tested in the present study can be successfully used for bonding orthodontic molar tubes under dry and saliva-contaminated enamel surface conditions.

Comparative Evaluation of Retention, Cariostatic Effect and Discoloration of Conventional and Hydrophilic Sealants - A Single Blinded Randomized Split Mouth Clinical Trial

Introduction:

Pit and fissures are approximately eight times vulnerable than the smooth surface caries lesion. Sealants are effective in preventing, arresting, and progression of pit-and-fissure occlusal caries lesions. The failure of sealant resin-based retention is mainly attributed to the moisture contamination. To overcome this drawback, UltraSeal XT^® hydro, a moisture-friendly sealant, has been introduced.

Aim:

This study aimed to compare and evaluate the retention, cariostatic effect, and discoloration of conventional Clinpro™ 3M™ ESPE™ and hydrophilic UltraSeal XT^® sealants among 12 to 15-year-old schoolchildren for 3 months.

Materials and Methods:

A single-blinded, randomized, split-mouth clinical trial was conducted among thirty schoolchildren aged 12–15 years. Sealants used in the present study were Group I – Clinpro™ and Group II – UltraSeal XT^® hydro. Sealants were provided in the school by two operators based on the computer-generated random sequence and the study participants were evaluated after 3 months for sealant coverage, caries incidence, and discoloration using Color, Coverage and Caries sealant evaluation system. Sealant coverage between the two sealants was compared using Mann–Whitney U-test and Z-test for proportions.

Results:

A total of 47 teeth (78.3%) with UltraSeal XT^® Hydro had the sealant covering in all the fissures compared to Clinpro™ 3M™ ESPE™ which was 46.7% (28 teeth) and the difference was observed to be statistically significant.

Conclusion:

Hydrophilic UltraSeal XT^® Hydro yielded better sealant coverage (retention) compared to the conventional Clinpro™ 3M™ ESPE™. No difference was observed with regard to cariostatic effect and discoloration.

Comparative Evaluation of the Viscosity and Length of Resin Tags of Conventional and Hydrophilic Pit and Fissure Sealants on Permanent Molars: An In vitro Study

Background:

The World Health Organization considers sealing the pit and fissures as a primary preventive measure and is one of the most effective, least invasive means to ensure the complete protection of the occlusal surface from the carious phenomenon. In vitro tests play a vital role in providing the necessary information regarding the efficacy of newer brands of sealants in a short period. Therefore, the aim of the present study was to evaluate and compare the viscosity and length of resin tag of conventional and hydrophilic sealant on permanent molars.

Materials and Methods:

Twenty extracted third molars were randomly divided into two groups: Group I: Conventional sealant (Clinpro 3M ESPE) and Group II: Hydrophilic sealant (UltraSeal XT Hydro). Occlusal surfaces of each tooth were pretreated with the acid etchant, and the respective sealants were placed. Both the groups were then subjected to thermocycling and sectioned longitudinally. The sectioned tooth specimens were examined under scanning electron microscope for resin tag length measurements. Viscosities were evaluated using an Anton Paar viscometer. Independent t-test was used to compare the difference in mean resin tag length of Group I and Group II sealants.

Results:

Viscosity measurements of Group I and Group II were found to be 0.9 mega Pascal (MPa) and 0.7 MPa and the mean resin tag length of Group II (10.03 ± 1.00 μm) was found to be higher than Group I (7.46 ± 0.95 μm) and was found to be significant statistically (P = 0.001).

Conclusion:

Based on the results of the present study, it can be concluded that Group II sealant exhibited lower viscosity and formed resin tag of sufficient length than that of Group I sealants. Therefore, hydrophilic sealant showed better results as compared to a conventional sealant.

Efeito da contaminação por saliva na resistência adesiva de braquetes cerâmicos utilizando uma resina ortodôntica hidrofílica

Resumo Introdução Alguns fatores, como a presença de saliva, são capazes de influenciar a adesão do braquete ao dente durante o procedimento de colagem e podem causar falha da resistência adesiva. Objetivo O objetivo deste estudo foi avaliar a resistência ao cisalhamento de braquetes cerâmicos ortodônticos colados com Transbond XT e Transbond Plus Color Change em esmalte de dentes bovinos, contaminado e não contaminado por saliva, além de analisar o local da falha adesiva. Material e método Sessenta incisivos bovinos foram divididos aleatoriamente em quatro grupos (n=15), de acordo com o material de colagem e a presença de contaminação: Grupo 1 (G1): colagem com Transbond XT na ausência de contaminação; Grupo 2 (G2): colagem com Self Etching Pimer e Transbond Color Change na ausência de contaminação; Grupo 3 (G3): colagem com Transbond XT na presença de contaminação, e Grupo 4 (G4): colagem com Self Etching Primer e Transbond Color Change na presença de contaminação. Resultado O teste não paramétrico de Kruskal-Wallis mostrou que G1 diferiu estatisticamente (p<0,05) de G2 e G3. Não houve diferença estatística significativa entre os demais grupos. O índice de adesivo remanescente (IAR) variou entre 2 e 3 no G1 e entre 0 e 1 nos outros grupos. Conclusão A contaminação por saliva diminui a resistência adesiva ao cisalhamento de braquetes cerâmicos colados com a resina hidrofóbica Transbond XT convencional. Por outro lado, a utilização da resina hidrofílica Transbond Plus Color Change associada ao Self Etching Primer, em ambiente contaminado por saliva, confere resistência adesiva adequada para o seu uso clínico.

Effectiveness of pit and fissure sealants bonded with different adhesive systems: a prospective randomized controlled trial

OBJECTIVES

To evaluate and compare the clinical retention of a resin-based fissure sealant placed with an intermediate layer of etch-and-rinse (ER) or self-etch (SE) adhesives.

MATERIALS AND METHODS

Two hundred twenty-eight sealants were placed in 57 children with previously unsealed, caries-free permanent first molars, employing a split-mouth design. The teeth were randomized into four groups (n = 57 teeth/groups) according to the adhesive system placed under the tested sealant (Delton FS+; Dentsply). Group 1 (control): no bonding agent (conventional acid-etch sealant); group 2: prior enamel etch + ER adhesive (XP Bond; Dentsply); group 3: SE adhesive (Clearfil SE Bond; Kuraray) without prior etching; and group 4: prior enamel etch + SE adhesive (Clearfil SE Bond). Clinical assessments were performed according to modified USPHS criteria at 1, 3, 6, 12, 18, and 24 months. The data were analyzed statistically using Fisher's Exact test, the Kaplan-Meier analysis, and the Log-rank test.

RESULTS

At 24 months, sealants bonded with XP Bond and Clearfil SE Bond with prior enamel etching showed similar retention rates (p > 0.05), and these rates were significantly better than the rates of the conventional sealant and Clearfil-SE groups (p < 0.05). There was no significant difference between the retention rates of the latter two groups (p > 0.05). The cumulative survival rates on palatal/buccal surfaces showed similar outcomes as with occlusal surfaces: XP Bond (94%), Clearfil SE Bond + acid-etch (94%), conventional sealant (52%), and Clearfil SE Bond only (37%).

CONCLUSIONS

Application of the tested ER adhesive and the SE adhesive with enamel etching significantly improved the clinical retention of Delton-FS over the 24-month period.

CLINICAL RELEVANCE

The use of a resin-based fissure sealant placed with ER or SE adhesive with prior acid-etching yielded better retention than the conventional sealant over the 24-month period.

Bond Strength of a Bisphenol-A-Free Fissure Sealant With and Without Adhesive Layer under Conditions of Saliva Contamination

Dental sealants are important for prevention of carious lesions, if they have good shear strength. The aim of this study was to evaluate the shear bond strength (SBS) of two sealants to saliva-contaminated and non-contaminated enamel with and without an intermediate adhesive layer underneath the sealant. Ninety flat enamel surfaces from human third molars were randomly assigned to 6 groups (n=15): F (control): Fluroshield(tm) sealant; EWB (control): Embrace(tm) WetBond(tm); SB/F: Single Bond adhesive system + F; SB/EWB, s-SB/F and s-SB/EWB. In the s-SB/F and s-SB/EWB groups, the acid-etched enamel was contaminated with 0.01 mL of fresh human saliva for 20 s. Sealant cylinders were bonded to enamel surface with and without an intermediate adhesive system layer. The shear tests were performed using a universal testing machine (0.5 mm/min). Data were analyzed statistically by Kruskal-Wallis and Mann-Whitney tests (α=0.05). F presented higher mean SBS than EWB in all experimental conditions. The lowest SBS mean was obtained for EWB on contaminated enamel (p<0.05). In conclusion, an adhesive system layer should be used prior to sealant placement, in both dry and saliva-contaminated enamel. F had the best performance in all experimental conditions. EWB sealant showed very low results, but an adhesive layer underneath the sealant increased its SBS even after salivary contamination.

Sealing of adhesive systems in ferric sulfate-contaminated dentinal margins in class V composite resin restorations

Background. Hemostatic agents are applied to prepare an isolated bleeding-free condition during dental treatments and can influence adhesive restorations. This study evaluated the effect of a hemostatic agent (ViscoStat) on microleakage of contaminated dentinal margin of class V composite resin restorations with three adhesives. Methods. Sixty freshly extracted human molars were selected and class V cavities (3×3×1.5 mm) were prepared on buccal and lingual surfaces. Gingival margins of the cavities were placed below the cementoenamel junction. The teeth were divided into six groups randomly. The adhesives were Excite, AdheSE and AdheSE One. In three groups, the gingival walls of the cavities were contaminated with ViscoStat and then rinsed. The cavities were restored with composite resin and light-cured. After storage in distilled water (37°C) for 24 hours and polishing, the samples were thermocycled and sealed with nail varnish. Then they were stored in 1% basic fuchsin for 24 hours, rinsed and mounted in self-cured acryl resin, followed by sectioning buccolingually. Dye penetration was observed under a stereomicroscope and scored. Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U tests. P<0.05 was set as the level of significance. Results. Only in the Excite group, contamination did not have adverse effects on dentin microleakage (P > 0.05). In the contaminated groups, Excite had significantly less microleakage than the others (P = 0.003). AdheSE and AdheSE One did not exhibit significant difference in microleakage (P > 0.05). Conclusion. ViscoStat hemostatic agent increased dentinal microleakage in AdheSE and AdheSE One adhesives with no effect on Excite.

An evaluation and comparison of the shear bond strength of two newly formulated primer systems with a conventional primer system under different conditions: An in vitro study

Aims and Objectives

This study was carried to evaluate the shear bond strength of brackets bonded with self-etching primer and moisture insensitive primer (MIP) and compare it with the conventional adhesive system.

Materials and Methods

A total of 90 extracted human premolar teeth were selected and divided into three groups of 30 teeth each with two sub groups (dry and wet), of 15 teeth each. Each group was bonded with three different types of bonding systems namely visible light cure Clearfil Liner Bond 2V, MIP and Transbond XT. These groups were named SD, MD and CD in dry conditions and SW, MW and CW in wet condition and each of these groups were color coded. The shear bond strength of the bonding system in each group was tested using Universal testing machine Instron (Instron model:4206, Instron Corporation, USA).

Results

In dry condition all three groups showed good bond strength. Self-etch primer showed the average highest bond strength, followed by Transbond XT and then MIP. In wet condition MIP has highest bond strength, followed by self-etching primer and Transbond XT.

Conclusion

Under dry conditions conventional primer is the material of choice. Under wet conditions, MIP showed the highest bond strength and hence can be considered to be a material of choice.

Effect of saliva contamination on the shear bond strength of a new self-etch adhesive system to dentin

AIMS AND OBJECTIVES

To evaluate the effect of saliva contamination on the shear bond strength of a new two-step self-etch adhesive (P90 system adhesive) to dentin and to determine the effect of contaminant removing treatments on the recovery of bond strengths.

MATERIALS AND METHODS

The buccal surfaces of 40 human premolars were ground to expose dentin. The specimens were randomly divided into four groups. Group 1 is uncontaminated and serves as the control group. Further groups were divided based on the step in the bonding sequence when the contamination had occurred as follows: Group 2 (primer, saliva contamination, rinse and dry), group 3 (after procedure of group 2, reapplication of primer), and group 4 (after procedure like in control group, saliva contamination, rinse and dry). Filtek P90 composite resin cylinders of 3 mm diameter and 3 mm length were fabricated on the surfaces. Shear bond strength testing was done in an Instron Universal Testing Machine and the data were subjected to one-way analysis of variance (ANOVA) and Student's t-test.

RESULTS

With P90 system adhesive, group 2 and group 4 showed lower shear bond strength than group 1 (control) and group 3 (P < 0.05).

CONCLUSION

Saliva contamination significantly decreased the shear bond strength of the adhesive to dentin.

Shear bond strength of orthodontic brackets and disinclusion buttons: effect of water and saliva contamination

PURPOSE

The aim of this study was to assess the effect of water and saliva contamination on the shear bond strength and failure site of orthodontic brackets and lingual buttons.

MATERIALS AND METHODS

120 bovine permanent mandibular incisors were randomly divided into 6 groups of 20 specimens each. Both orthodontic brackets and disinclusion buttons were tested under three different enamel surface conditions: (a) dry, (b) water contamination, and (c) saliva contamination. Brackets and buttons were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bond strength values and adhesive failure rate were recorded. Statistical analysis was performed using ANOVA and Tukey tests (strength values) and Chi squared test (ARI Scores).

RESULTS

Noncontaminated enamel surfaces showed the highest bond strengths for both brackets and buttons. Under water and saliva contamination orthodontic brackets groups showed significantly lower shear strengths than disinclusion buttons groups. Significant differences in debond locations were found among the groups under the various enamel surface conditions.

CONCLUSIONS

Water and saliva contamination of enamel during the bonding procedure lowers bond strength values, more with orthodontic brackets than with disinclusion buttons.

Evaluation of different types of enamel conditioning before application of a fissure sealant

The aim of the study was to compare fissure sealant quality after mechanical conditioning of erbium-doped yttrium aluminium garnet (Er:YAG) laser or air abrasion prior to chemical conditioning of phosphoric acid etching or of a self-etch adhesive. Twenty-five permanent molars were initially divided into three groups: control group (n = 5), phosphoric acid etching; test group 1 (n = 10), air abrasion; and test group 2, (n = 10) Er:YAG laser. After mechanical conditioning, the test group teeth were sectioned buccolingually and the occlusal surface of one half tooth (equal to one sample) was acid etched, while a self-etch adhesive was applied on the other half. The fissure system of each sample was sealed, thermo-cycled and immersed in 5% methylene dye for 24 h. Each sample was sectioned buccolingually, and one slice was analysed microscopically. Using specialized software microleakage, unfilled margin, sealant failure and unfilled area proportions were calculated. A nonparametric ANOVA model was applied to compare the Er:YAG treatment with that of air abrasion and the self-etch adhesive with phosphoric acid (α = 0.05). Test groups were compared to the control group using Wilcoxon rank sum tests (α = 0.05). The control group displayed significantly lower microleakage but higher unfilled area proportions than the Er:YAG laser + self-etch adhesive group and displayed significantly higher unfilled margin and unfilled area proportions than the air-abrasion + self-etch adhesive group. There was no statistically significant difference in the quality of sealants applied in fissures treated with either Er:YAG laser or air abrasion prior to phosphoric acid etching, nor in the quality of sealants applied in fissures treated with either self-etch adhesive or phosphoric acid following Er:YAG or air-abrasion treatment.

Disinclusion of unerupted teeth by mean of self-ligating brackets: effect of blood contamination on shear bond strength

Objectives: The aim of this study was to assess the effect of blood contamination on the shear bond strength and failure site of three different orthodontic self-ligating brackets. Study Design: 240 bovine permanent mandibular incisors were randomly divided into 12 groups of 20 specimens each. Orthodontic self-ligating brackets were tested under four different enamel surface conditions: a) dry, b) blood contamination before priming, c) blood contamination after priming, d) blood contamination before and after priming. Brackets were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bond strength values and adhesive failure rate were recorded. Statistical analysis was performed using ANOVA and Tukey tests (strength values), and Chi squared test (ARI Scores). Results: Non-contaminated enamel surfaces showed highest bond strengths for all self ligating brackets. Under blood-contamination shear bond strengths lowered for all brackets tested. Groups contaminated before and after primer application showed the lowest shear bond strength. Significant differences in debond locations were found among the groups under the various enamel surface conditions. Conclusions: Blood contamination of enamel during the bonding procedure lowers bond strength values of self ligating brackets, expecially when contamination occur in different times of the bonding procedure.

Key words:Disinclusion, self ligating brackets, blood, contamination, enamel, orthodontics, oral surgery.

The effect of various surface contaminants on the microleakage of two different generation bonding agents: A stereomicroscopic study

Aim:

The aim of this in vitro study was to evaluate the microleakage of two different generation bonding agents in the presence of various surface contaminants.

Materials and Methods:

Class V cavities were prepared on 150 extracted human permanent molars. The samples were randomly divided into two main groups of 75 teeth each. Group I: Fifth generation bonding system (Single Bond, 3M). Group II: Seventh generation bonding system (iBond, Kulzer). Subgroups were formed according to exposure to different surface contaminants (saliva, blood, caries disclosing agent and haemostatic agent). Cavities were restored with hybrid composite (Z-100, 3M) and evaluated for microleakage. The scores were subjected to ‘t’ test and analysis of variance (ANOVA) test.

Results:

Single Bond and iBond did not provide complete resistance to microleakage when there was no contamination. Microleakage was minimum in the no contamination subgroup and maximum with the haemostatic agent subgroup for both the groups.

Conclusion:

Single bond showed lesser micro leakage in contaminated conditions.

Blood contamination effect on shear bond strength of an orthodontic hydrophilic resin

Objective

The aim of this study was to assess the impact of blood contamination on shear bond strength (SBS) and bond failure pattern of metallic brackets bonded using a new hydrophilic resin.

Material and Methods

Eighty human premolars were randomly allocated into 4 groups (n=20) according to the bonding material and contamination pattern. GI: brackets bonded with the Transbond XT conventional system without contamination; GII: brackets bonded with the Transbond XT conventional system with blood contamination; GIII: brackets bonded with the Transbond Self Etching Primer and Transbond Plus Color without contamination; GIV: brackets bonded with the Transbond Self Etching Primer and Transbond Plus Color with blood contamination. The specimens were stored in distilled water at 37ºC for 24 h and then submitted to SBS test at a crosshead speed of 0.5 mm/min. After bond failure, the enamel surfaces were observed under an optical microscope at 40x magnification.

Results

Blood contamination decreased (P<0.05) shear bond strength when both the hydrophobic (GII) and the hydrophilic resin (GIV) were used. However, the bond strength of Transbond Color Change group was significantly higher (P<0.05) than that of the Transbond XT conventional system group under blood contamination condition. Under dry conditions no difference was observed between the hydrophobic and hydrophilic resin groups. Regarding the bond failure pattern, when blood contaminated the enamel, the adhesive remnant index (ARI) showed predominance of scores 0 and 1, which indicates low adhesion to enamel.

Conclusions

Although there was a significant decrease in the shear bond strength for both adhesive systems under blood contamination, the hydrophilic system showed significantly higher bond strength than the hydrophobic resin adhesive. Therefore, it is advisable to use the hydrophilic resin under risk of blood contamination.

In vitro evaluation of influence of salivary contamination on the dentin bond strength of one-bottle adhesive systems

AIM

To evaluate the effect of salivary contamination on the bond strength of one-bottle adhesive systems - (the V generation) at various stages during the bonding procedure and to investigate the effect of the contaminant removing treatments on the recovery of bond strengths.

MATERIALS AND METHODS

In this study the V generation one-bottle system - (Adper Single Bond) was tested. Fifty caries-free human molars with flat dentin surfaces were randomly divided into five groups of ten teeth each: Group I had 15 second etching with 35% Ortho Phosphoric acid, 15 second rinse and blot dried (Uncontaminated); Group II contaminated and blot dried; Group III contaminated and completely dried; Group IV contaminated, washed, blot dried; Group V contaminated, retched washed, and blot dried. The bonding agent was applied and resin composite (Z-100 3M ESPE) was bonded to the treated surfaces using the Teflon mold. The specimens in each group were then subjected to shear bond strength testing in an Instron Universal testing machine at a crosshead speed of 1 mm / minute and the data were subjected to one way ANOVA for comparison among the groups (P<0.05).

RESULTS

There was a significant difference between the group that was dried with strong oil-free air after contamination (Group III) and the other groups. When the etched surface was contaminated by saliva, there was no statistical difference between the just blot dry, wash, or the re-etching groups (Groups II, IV, V) if the dentin surface was kept wet before priming. When the etched dentin surface was dried (Group III) the shear bond strength decreased considerably.

CONCLUSION

The bond strengths to the tooth structure of the recent dentin bonding agents are less sensitive to common forms of contamination than assumed. Re-etching without additional mechanical preparation is sufficient to provide or achieve the expected bond strength.

Effects of saliva contamination and decontamination procedures on shear bond strength of self-etch dentine bonding systems: An in vitro study

Objective:

This study aims to evaluate the effect of saliva contamination on the shear bond strength of two self-etch dentine bonding systems and also investigate the effect of decontamination procedure on the recovery of bond strength.

Materials and Methods:

Sixty premolars extracted for orthodontic reason were obtained and the buccal surfaces of teeth were reduced to create a flat dentine surface. The samples were randomly divided into three sub-groups for AdheSE (ASE) (Ivoclar – Vivadent, Schaan, Liechtenstein) and three sub-groups for Adper Prompt Self-Etch Adhesive (ADP) (3M ESPE, St Paul, MN, USA) of 10 each. For AdheSE (ASE); ASE-I was the control group (primer applied to fresh dentine surface), ASE-II was the contamination group (primer applied, followed by saliva contamination and then air dried) and ASE-III was the decontamination group (primer applied, followed by saliva contamination, air dried and then primer reapplied). For Adper Prompt (ADP); ADP-I was the control group (self-etch adhesive applied to fresh dentine surface), ADP-II was the contamination group (self-etch adhesive applied, followed by saliva contamination and then air dried) and ADP-III was the decontamination group (self-etch adhesive applied, followed by saliva contamination, air dried and then self-etch adhesive reapplied). Followed by the bonding procedure, a 5 mm composite resin block with Filtek P-60 (3M ESPE, St Paul, MN, USA) was built on the substrate. Shear bond strength (SBS) was tested with Instron Universal testing machine (Instron Corporation, Canton, MA, USA) with a cross head speed of 1 mm per minute. Data obtained was subjected to one way ANOVA test, while the inter group comparison was made using Tukey’s multiple comparison and Unpaired t-test.

Results:

In AdhSE group (ASE), the sub-group ASE-II (contamination group) [5.4 ± 2.2 MPa] showed lower SBS than ASE-I [11.8 ± 2.6 MPa] and ASE-III [8.9 ± 3.3 MPa], which was statistically significant. There was no significant difference in the bond strength between the ASE-I (control group) and ASE-III (decontamination group). In Adper Prompt group (ADP), there was a severe decrease of bond strength in ADP-II (contamination group) [4.6 ± 1.1 MPa] when compared to ADP-I (control group) [7.4 ± 1.4 MPa] and ADP-III (decontamination subgroup) [14.1 ± 2.2 MPa] which was statistically significant. The bond strength of ADP-III wherein Adper Prompt bonding agent was reapplied after salivary contamination was found to be statistically significant than ADP-I and ADP-II.

Conclusion:

Saliva contamination reduces the dentine bond strength of both the self-etch systems; AdheSE and Adper Prompt. Re-application of the primer for the AdheSE and re-application of the adhesive for the Adper Prompt after air drying the saliva off can recover the dentine bond strength. In the Adper Prompt group, the added application of adhesives to decontaminate saliva not only recovered the bond strength but also improved it significantly.

Effect of mucoprotein on the bond strength of resin composite to human dentin

The purpose of this study was to test the bond strength and analyze the morphology of the dentin-adhesive interface of two etch and rinse and two self-etch adhesive systems with two kinds of artificial saliva (with and without 450 mg/L mucin) contamination under different conditions of decontaminating the interface. Bonded specimens were sectioned perpendicularly to the bonded surface in 1-mm thick slabs. These 1-mm thick slabs were remounted in acrylic blocks and sectioned in sticks perpendicular to the bonding interfaces with a 1-mm(2) area. Nine specimens from each condition were tested after 24 h on a testing machine (Instron) at a speed of 0.5 mm/min for a total of 360 specimens. Mean and standard deviations of bond strength (MPa) were calculated. ANOVA showed significant differences as well as Fisher's PLSD intervals (p < 0.05). The following values are the results for different groups: Control group 34-60 MPa, saliva without mucin 0-52 MPa, and saliva with mucin 0-57 MPa. Failure sites were mixed and adhesive failure was common for the low bond strength results. P&BNT with ideal conditions and following the manufacturer's instructions (control) had the highest bond strengths and the dentin-adhesive interface exhibited an ideal morphology of etch-and-rinse system. SEM gave complementary visual evidence of the effect in the dentin/adhesive interface structure with some contaminated conditions compared with their respective control groups. This in vitro artificial saliva model with and without mucin showed that an organic component of saliva could increase or decrease the bond strength depending on the specific bonding agent and decontamination procedure.

Influence of decontamination procedures on shear forces after contamination with blood or saliva

INTRODUCTION

Despite rapid development in adhesive technology, contamination of bonding surfaces remains a major problem. The aims of this study were to evaluate the influence of contamination on bond strength and to investigate possible decontamination procedures.

METHODS

Four bonding systems were evaluated for their shear bond strengths under 5 bonding situations: control (without contamination and decontamination); contamination with blood; contamination with saliva; decontamination with water and air, and repriming after blood contamination; and decontamination with water and air, and repriming after saliva contamination. The 25 specimens of each group consisted of composite blocks bonded to bovine teeth. Shear forces were measured with a testing machine after thermocycling.

RESULTS

The 3 composite primers showed similar behavior. With the exception of Transbond SEP (3M Unitek, Monrovia, Calif) with saliva contamination, all contaminated samples showed greatly reduced shear forces. The control and decontaminated groups showed shear forces about 20 MPa. The resin-modified glass ionomer, however, did not reach clinically sufficient bond strengths in either setup.

CONCLUSIONS

Decontamination with water and air and repriming is sufficient after contamination with blood or saliva. Etching again is not necessary. The bond strength of Transbond SEP was not significantly altered by saliva contamination and can be recommended for conventional bonding procedures.

Effect of blood contamination on shear bond strength of orthodontic brackets and disinclusion buttons

Our aim was to assess the effect of blood contamination on the shear bonding strength and sites of failure of orthodontic brackets and bondable buttons. We randomly divided 160 bovine permanent mandibular incisors into 8 groups of 20 specimens each. Both orthodontic brackets (Step brackets, Leone, Sesto Fiorentino, Italy) and bondable buttons (Flat orthodontic buttons, Leone, Sesto Fiorentino, Italy) were tested on four different enamel surfaces: dry; contamination with blood before priming; after priming; and before and after priming. Brackets and buttons were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bonding strength and the rate of adhesive failures were recorded. Data were analysed using the analysis of variance (ANOVA), Scheffè tests, and the chi-square test. Uncontaminated enamel surfaces showed the highest bonding strengths for both brackets and buttons. When they were contaminated with blood, orthodontic brackets had significantly lower shear strengths than bondable buttons (P=0.0001). There were significant differences in sites of failure among the groups for the various enamel surfaces (P=0.001). Contamination of enamel by blood during bonding lowers the strength of the bond, more so with orthodontic brackets than with bondable buttons.

Effect of saliva contamination on bracket failure with a self-etching primer: a prospective controlled clinical trial

INTRODUCTION

The aim of this study was to evaluate in vivo the effect of saliva contamination at different stages of the bonding procedure on the bond failure rate and the adhesive remaining on teeth after debonding brackets bonded with a hydrophilic self-etching primer (Transbond Plus self-etching primer [TSEP], 3M Unitek, Monrovia, Calif).

METHODS

This was a prospective controlled clinical trial. The sample consisted of 46 patients with similar treatment plans and mechanotherapies. Stainless steel brackets (n = 531) were bonded with TSEP. The patients were divided into 2 groups: contamination with saliva before TSEP application and contamination with saliva after TSEP application. In both groups, saliva was applied in a split-mouth design. Diagonally opposite quadrants were allocated to either the contaminated group (contamination before [153 teeth] or after [115 teeth] TSEP application) or to the uncontaminated control group (263 teeth). Recording of failed brackets involved only first-time failures, and the observation period was a minimum of 6 months.

RESULTS

The chi-squared test showed no significant differences (P = 0.11) in bracket failures between the groups. Kaplan-Meier survival analysis detected no significant differences in the survival rates between the 3 groups (P = 0.51). Most bond failures occurred during the first 3 months. In all 3 groups, the adhesive remaining on teeth after debonding tended to be less than half.

CONCLUSIONS

These findings suggest that saliva contamination before or after application of self-etching primer does not increase the clinical risk of bond failure.

The effect of moisture on the shear bond strength of gold alloy rods bonded to enamel with a self-adhesive and a hydrophobic resin cement

The aim of this in vitro study was to investigate the influence of enamel moisture on the shear bond strength (SBS) of a hydrophobic resin cement, Maximum Cure (MC), and a self-adhesive resin cement, Multilink Sprint (MLS), after etching of the enamel. Forty cylindrical gold alloy rods were used to simulate the Incognito lingual bracket system. They were bonded to the enamel of 40 human teeth embedded in self-cured acrylic resin. Twenty were bonded with MC (10 on dry and 10 on wet enamel) and 20 with MLS (10 on dry and 10 on wet enamel). The SBS of MC and MLS was determined in a universal testing machine and the site of bond failure was defined by the adhesive remnant index (ARI). A Kruskal-Wallis test was performed followed by Games-Howell post hoc pairwise comparison tests on the SBS results (P < 0.05) and a chi-square test was used for the analysis of ARI scores (P < 0.05). On dry enamel, no significant differences between MC (58 +/- 5 MPa) and MLS (64 +/- 13 MPa) were noted. On wet enamel, the adherence of MC (6 +/- 8 MPa) and MLS (37 +/- 13 MPa) significantly decreased but to a lesser extent for MLS. The ARI scores corroborated these results. In conclusion, MC did not tolerate moisture. MLS was also affected but maintained sufficient adherence.

Shear bond strength of a sealant to contaminated-enamel surface: influence of erbium : yttrium-aluminum-garnet laser pretreatment

BACKGROUND

Salivary contamination is one of the factors that can disturb the sealing process and interfere in the longevity of pit and fissure sealants. Erbium : yttrium-aluminum-garnet (Er : YAG) laser could influence the bond strength of enamel and increase the acid resistance.

PURPOSE

To evaluate the influence of Er : YAG laser on the shear bond strength of a sealant to a salivary contaminated enamel surface.

METHODS

Twenty-four third molars had the roots sectioned 2 mm coronal to the cementoenamel junction. The crowns were mesiodistally sectioned providing 48 halves that were embedded in polyester resin. Enamel was flattened and a 2-mm diameter bonding area was demarcated. Specimens were randomly assigned to two groups according to the superficial pretreatment-37% phosphoric acid (A) and Er : YAG laser (80 mJ/2 Hz) + phosphoric acid (L), which were subdivided into two groups (N = 12), without salivary contamination (C) and with salivary contamination (SC). To contaminate the specimens, 0.25 mL of human fresh saliva was applied for 20 seconds and then dried. Fluroshield sealant was applied in all specimens. After storage, shear bond strength of samples were tested in a universal testing machine.

RESULTS

Means in MPa were: AC-14.61 (+/-2.52); ASC-6.66 (+/-2.34); LC-11.91 (+/-1.34); and LSC-2.22 (+/-0.66). Statistical analysis revealed that surfaces without salivary contamination and with acid treatment had the highest mean (p < 0.05). The group with salivary contamination treated by Er : YAG laser followed by phosphoric acid application presented the lowest bond values (p < 0.05).

CONCLUSIONS

The phosphoric acid etching under dry condition yielded better bonding performance. Er : YAG laser was not able to increase the effectiveness of conventional acid etching of enamel in the bond of sealants in both dry and wet conditions.

CLINICAL SIGNIFICANCE

Under the conditions of this study, the conventional etching protocol (phosphoric acid without salivary contamination) is still preferable to laser-conditioning enamel surface prior to sealant application.

Bond strength of a pit-and-fissure sealant associated to etch-and-rinse and self-etching adhesive systems to saliva-contaminated enamel: individual vs. simultaneous light curing

This study evaluated in vitro the shear bond strength (SBS) of a resin-based pit-and-fissure sealant [Fluroshield (F), Dentsply/Caulk] associated with either an etch-and-rinse [Adper Single Bond 2 (SB), 3M/ESPE] or a self-etching adhesive system [Clearfil S3 Bond (S3), Kuraray Co., Ltd.] to saliva-contaminated enamel, comparing two curing protocols: individual light curing of the adhesive system and the sealant or simultaneous curing of both materials. Mesial and distal enamel surfaces from 45 sound third molars were randomly assigned to 6 groups (n=15), according to the bonding technique: I - F was applied to 37% phosphoric acid etched enamel. The other groups were contaminated with fresh human saliva (0.01 mL; 10 s) after acid etching: II - SB and F were light cured separately; III - SB and F were light cured together; IV - S3 and F were light cured separately; V - S3 and F were light cured simultaneously; VI - F was applied to saliva-contaminated, acid-etched enamel without an intermediate bonding agent layer. SBS was tested to failure in a universal testing machine at 0.5 mm/min. Data were analyzed by one-way ANOVA and Fisher's test (alpha=0.05).The debonded specimens were examined with a stereomicroscope to assess the failure modes. Three representative specimens from each group were observed under scanning electron microscopy for a qualitative analysis. Mean SBS in MPa were: I-12.28 (+/-4.29); II-8.57 (+/-3.19); III-7.97 (+/-2.16); IV-12.56 (+/-3.11); V-11.45 (+/-3.77); and VI-7.47 (+/-1.99). In conclusion, individual or simultaneous curing of the intermediate bonding agent layer and the resin sealant did not seem to affect bond strength to saliva-contaminated enamel. S3/F presented significantly higher SBS than the that of the groups treated with SB etch-and-rinse adhesive system and similar SBS to that of the control group, in which the sealant was applied under ideal dry, noncontaminated conditions.

Effects of moisture conditions of dental enamel surface on bond strength of brackets bonded with moisture-insensitive primer adhesive system

The purposes of this study were to evaluate the effects of different degrees of water contamination on the shear bond strength of orthodontic brackets bonded to dental enamel with a moisture-insensitive primer (MIP) adhesive system and to compare the modes of bracket/adhesive failure. A total of 68 human premolars were divided into four groups by primers and enamel surface conditions (desiccated, blot dry, and overwet). In group I, the hydrophobic Transbond XT primer adhesive system was used under desiccated conditions for bonding the brackets; in group II, the hydrophilic Transbond MIP adhesive system was used under desiccated conditions; in group III, the hydrophilic Transbond MIP adhesive system was used under blot dry conditions; and in group IV, the hydrophilic Transbond MIP adhesive system was used under overwet conditions. Shear bond strength was measured with a universal testing machine, and the mode of bracket/adhesive failure was determined according to the adhesive remnant index. The mean shear bond strengths were not significantly different among groups I, II, and III, and were higher than the clinically required range of 6 to 8 MPa. The mean shear bond strength achieved in group IV was significantly lower than that achieved in groups I, II, and III, and also lower than the clinically required values. Bond failure occurred at the enamel-adhesive interface more frequently in group IV than in groups I and III. To achieve clinically sufficient bond strengths with the hydrophilic MIP adhesive system, excess water should be blotted from the water-contaminated enamel surface.

Does atropine sulphate improve orthodontic bond survival? A randomized clinical trial

INTRODUCTION

The antisialagogue atropine sulphate has been used for many years as an adjunct to orthodontic bonding to reduce moisture contamination. The aims of this study were to investigate the effect of atropine sulphate premedication on orthodontic bond failures and to evaluate the attitudes of patients and parents toward its use in orthodontics.

METHODS

After ethics committee approval, 51 patients (mean age, 14 years 7 months) were enrolled in this clinical trial. They were randomized to receive 2 interventions, atropine sulphate premedication (600 microg) or no premedication (control) with a Battenburg design (split-mouth). Overall, 852 brackets and 362 molar tubes were bonded. Bond failure data were collected over a 12-month period and analyzed with Kaplan-Meier survival probabilities and the log rank and Wilcoxon tests. Patient-centered outcome measures included a questionnaire relating to treatment with antisialagogues.

RESULTS

The results showed no statistically significant difference in the bond survival rates between the 2 interventions--antisialagogue premedication or no premedication (P >.05). From the questionnaire, 94.1% of the subjects said they took the atropine sulphate before the bond appointment. Approximately 76% of them thought that taking medication before placement of orthodontic appliances was an acceptable part of treatment.

CONCLUSIONS

Although the use of a premedication to induce hypo-salivation before orthodontic bonding appears to be an acceptable procedure to most patients and their parents, we did not find a statistically significant effect on the observed bond failure rates. There is no evidence to support the routine use of atropine sulphate before orthodontic bonding.

Saliva Contamination Effect on Shear Bond Strength of Self-etching Primer with Different Debond Times

Objective: To evaluate shear bond strengths (SBSs) of a self-etching primer (SEP) following saliva contamination at different stages of bonding at debond times of 5, 15, and 30 minutes and 24 hours.

Materials and Methods: Two-hundred forty human premolars were divided into four groups: group 1, uncontaminated; group 2, saliva contamination after priming; group 3, saliva contamination before priming; and group 4, saliva contamination before and after priming. Four subgroups according to debond times of 5, 15, 30 minutes and 24 hours were composed. Metal brackets were bonded with an SEP (Transbond Plus) and light-cure adhesives paste (Transbond XT). SBS values and the adhesive remnants were determined.

Results: The highest SBS was obtained at a debond time of 24 hours for the control group. This was significantly different from the other groups. SBSs at 5, 15, and 30 minutes showed no significant difference from each other in the control group (P &gt; .05). Lowest SBSs were obtained at a debond time of 5 minutes for groups 1, 2, 3, and 4 (8.38, 7.10, 7.06, and 6.26 MPa, respectively) and were not significantly different from each other (P &gt; .05). SBSs at 24 hours were not significantly different from each other for groups 2, 3, and 4 (P &gt; .05). Significant differences were found in the adhesive remnant (P &lt; .001).

Conclusions: SEP (Transbond Plus) may produce clinically acceptable bracket bonding after 5, 15, and 30 minutes from time of placement on the teeth, even with light and heavy saliva contamination.

Effect of blood and saliva contamination on bond strength of brackets bonded with a protective liquid polish and a light-cured adhesive

INTRODUCTION

The application of a polymer coating to the labial enamel tooth surface before bonding can help keep white spot lesions from forming. Previous studies evaluating the effects of blood and saliva contamination on the bond strengths of light-cured composites showed significant reductions in bond strength values. The purpose of this study was to investigate whether the bond strength of a light-cured system (Transbond XT, 3M Unitek, Puchheim, Germany) used with a liquid polish (BisCover, Bisco, Schaumburg, Ill) is affected by contamination with blood or saliva.

METHODS

One hundred twenty permanent human premolars were randomly divided into 6 groups of 20. Various enamel surface conditions were studied: dry, blood contaminated, and saliva contaminated. A light-cured bonding system (Transbond XT) was used in all groups. The teeth in group 1 were bonded with Transbond XT. In the second group, BisCover polymeric resin polish was applied on the etched tooth surfaces before the brackets were bonded with Transbond XT resin. Comparison of the first and second groups showed no statistically significant difference. Groups 3 through 6 were bonded without Transbond XT. For groups 3 and 5, a layer of blood or saliva, respectively, was applied to the etched enamel followed by BisCover. In groups 4 and 6, blood or saliva, respectively, was applied on the light-cured BisCover. Shear forces were applied to the samples with a universal testing machine, and bond strengths were measured in megapascals.

RESULTS

The protective liquid polish (BisCover) layer did not affect bond strength.

CONCLUSIONS

Blood contamination on acid-etched surfaces affects bond strength more than saliva contamination. When a protective liquid polish (BisCover) is applied to the tooth surface, the effect of contamination by blood or saliva is prevented.

Effect of blood and saliva contamination on shear bond strength of brackets bonded with 4 adhesives

INTRODUCTION

The purpose of this study was to assess the effect of blood and saliva contamination on the shear bond strength of 4 orthodontic adhesives.

METHODS

Four adhesives (Transbond XT primer [3M Unitek, Monrovia, Calif], Transbond Plus self-etch primer [3M Unitek], Assure hydrophilic primer [Reliance, Itasca, Ill], and SmartBond cyanoacrylate [Gestenco, Gothenburg, Sweden]) were used to bond stainless steel maxillary central incisor brackets to 120 bovine permanent mandibular incisors. The teeth were randomly divided into 12 groups of 10 specimens, and each primer-adhesive combination was tested under different enamel conditions: dry, and blood and saliva contamination after priming. Shear forces were applied to the samples with a testing machine. Bond strengths were measured in megapascals.

RESULTS

Statistical evaluations showed that the shear bond strength of the SmartBond cyanoacrylate adhesive group was significantly lower than all other groups; however, it was the only adhesive that was not affected by contamination. Saliva and blood contamination resulted in significant drops in shear bond strengths of the Transbond XT and Assure groups. Transbond Plus self-etch primer was also negatively affected by blood contamination, although it was suitable for bonding with saliva contamination.

Discharge of lubricant from air turbine handpieces

OBJECTIVE

To demonstrate and quantify the discharge of lubricating oil from high-speed air turbine handpieces whilst running.

MATERIALS AND METHODS

Dye-marked oil (Kavospray, KaVo) was used to lubricate four handpieces (Quiet-Air, Midwest) and the air discharged from around the lower bearing was directed at the moving chart paper on a recorder whilst running for 40 minutes. Secondly, seven new handpieces (Quiet-Air, 300SE, Midwest; Topair 796, Topair 795, W+H; VIP-Sigma, Pana-air, NSK; Lares, Lares Research) were cleaned, weighed and then lubricated with unmarked oil (Kavospray, KaVo). Oil discharge was determined gravimetrically over runs of 240 minutes. Data were fitted to the logistic dose response function.

RESULT

The dye-marked oil tests showed that oil was discharged for at least 40 minutes in the direction of the bur. The gravimetric tests showed that oil continued to be discharged up to at least 240 minutes, and that the usual practice of removing excess lubricant by running for 1-2 minutes was ineffective in preventing cut-surface contamination.

SIGNIFICANCE

Bonding procedures in dentistry may be jeopardised by oil contamination from handpiece lubricants. Decontamination with a detergent is suggested as a means of ensuring effective adhesive dentistry.

Use of a self-etching adhesive on previously etched intact enamel and its effect on sealant microleakage and tag formation

AIM

This study verified the effects of a self-etching adhesive applied on pre-etched fissures (phosphoric acid 35%) on microleakage, penetration ability and tag formation of a fissure sealant.

METHODS

80 extracted sound human molar teeth were randomly divided into four groups and bisected in two equal parts, forming two subgroups, denominated A and B. Groups 1 and 2 were etched with phosphoric acid for 60 and 40s, respectively. Groups 3 and 4 were etched with phosphoric acid (40 and 20s, respectively) and afterwards treated with Xeno III (20s). All the procedures on sealant placement were performed under 90+/-2% relative humidity. The subgroups A and B were submitted to 1000 and 5000 thermal cycles, respectively. The samples were examined by light microscopy and by confocal laser scanning microscopy (CLSM) after sectioning. Microleakage, penetration ability, fissure type, tag formation quality and tag length were measured.

RESULTS

Etching with phosphoric acid for 60s showed statistically significantly lower microleakage when compared to the other groups and significantly better tag formation quality and longer tags compared to 20s H(3)PO(4) plus Xeno III. Fissure type and number of thermal cycles were not significant factors on sealant microleakage. The penetration ability of the sealant in the fissure systems was not influenced by the treatment regimes. Shallow fissures showed a significant better tag formation than deep fissures. No significant difference in the prevalence of fissure types was seen among the groups.

CONCLUSION

Etching fissures with phosphoric acid for 60s showed best results. The additional use of Xeno III did not improve fissure sealing under the conditions of this study.

Effect of primer precuring on the shear bond strength of orthodontic brackets

Two adhesive systems, Transbond APC II (3M Unitek, Monrovia, Calif) and Quick Cure (Reliance Orthodontic Products, Itasca, Ill), were used to determine the efficacy of precuring the liquid resin primer phase of the systems to increase shear bond strength. One hundred sixty bovine incisors were divided into groups of 20 specimens. In 1 group, the primer was cured before placement of the bracket with the filled adhesive material, and, in the other group, the primer was not precured. The shear-peel bond strength was tested with a testing machine at 30 minutes and 24 hours. No statistically significant difference in bond strength was found between the groups that had or had not been precured. More adhesive remained on the teeth with the Transbond when the primer was not precured. There is no advantage or disadvantage in bracket bond strength by precuring the primer before placing the bracket and filled component of the adhesive.

Effects of blood contamination on the shear bond strengths of conventional and hydrophilic primers

The purpose of this study was to assess the effect of blood contamination on the shear bond strength and failure site of 2 orthodontic primers (Transbond XT and Transbond MIP; 3M/Unitek, Monrovia, Calif) when used with adhesive-precoated brackets (APC II brackets; 3M/Unitek). One hundred twenty bovine permanent mandibular incisors were randomly divided into 8 groups; each group contained 15 specimens. Each primer-adhesive combination was tested under a different enamel surface condition: dry, blood contamination before priming, blood contamination after priming, or blood contamination before and after priming. Stainless steel APC II brackets were bonded to the teeth. After bonding, all samples were stored in distilled water at room temperature for 24 hours and subsequently tested for shear bond strength. Noncontaminated enamel surfaces had the highest bond strengths for both conventional and hydrophilic primers; their values were almost the same. Under blood-contaminated conditions, both primers showed significantly lower shear bond strengths. For each type of primer, no significant differences were reported among the blood-contaminated groups. Significant differences in debond locations were found among the groups bonded with the 2 primers under the various enamel surface conditions. Blood contamination of enamel during the bonding procedure of conventional and hydrophilic primers significantly lowers their bond strength values and might produce a bond strength that is not clinically adequate.

Effect of blood contamination on shear bond strength of brackets bonded with conventional and self-etching primers

This study assessed the effect of blood contamination on the shear bond strength and bond failure site of 2 different orthodontic primers (Transbond XT and Transbond Plus Self-Etching Primer, both from 3M Unitek, Monrovia, Calif) used with adhesive-precoated brackets. Four different enamel surface conditions were tested: (1) dry, (2) blood contamination before priming, (3) blood contamination after priming, and (4) blood contamination before and after priming. Noncontaminated enamel surfaces had the highest bond strengths for both conventional and self-etching primers, which produced almost the same strength values. Under blood-contaminated conditions, both primers showed significantly reduced shear bond strengths. For the conventional primer, no significant differences were reported among the blood-contaminated groups, whereas when the self-etching primer was used, condition 4 reduced significantly the bond strength values. Significant differences in debond locations were found among the groups bonded with the 2 primers under the various enamel surface conditions.

Factors affecting in vitro bond strength of bonding agents to human dentin

Four generations of total-etch (fourth, fifth) and self-etching (sixth, seventh) bonding agents for use with resin composites are commercially available in the United States. Innovations in bonding agents include: filled systems, release of fluoride and other agents, unit dose, self-cured catalyst, option of etching with either phosphoric acid or self-etching primer, and pH indicators. Factors that can affect in vitro bond strength to human dentin include substrate (superficial dentin, deep dentin; permanent versus primary teeth; artificial carious dentin), phosphoric acid versus acidic primers, preparation by air abrasion and laser, moisture, contaminants, desensitizing agents, astringents, and self-cured restorative materials. This article reviews studies conducted at the Houston Biomaterials Research Center from 1993 to 2003. Results show that in vitro bond strengths can be reduced by more than 50% when bonding conditions are not ideal.

Effect of artificial saliva contamination on pH value change and dentin bond strength

OBJECTIVE

This study was to examine the effect of artificial saliva contamination on pH change of the dentin surface and the micro-shear bond strength (MSBS) of the two bonding systems to contaminated dentin.

METHODS

Fifty-six human dentin disks were tested with two resin bonding systems: a self-etching primer system, Clearfil SE Bond (Kuraray Medical Inc., Tokyo, Japan), and a one-bottle adhesive system, Single Bond (3M-ESPE, St. Paul, MN). Dentin surfaces were conditioned with the self-etching primer (primer) or phosphoric acid (etchant) and divided into four groups: conditioning without contamination (conditioning), contamination with artificial saliva (contamination), re-conditioning the contaminated dentin (re-conditioning), water-rinsing the contaminated dentin and re-conditioning (rinsing and re-conditioning). The pH change on the dentin surface was measured using a pH-imaging microscope (SCHEM-100, Horiba Ltd, Kyoto, Japan) to estimate the acid-base characteristics of the conditioned and contaminated dentin surface. The MSBS to the dentin was examined after storage in distilled water at 37 degrees C for 1 week.

RESULTS

The pH of intact dentin surfaces was 6.9. Conditioning with the primer and etchant decreased the pH to 5.4 and 5.9, respectively. Saliva contamination increased the pH slightly, and re-conditioning decreased the pH again. The MSBS of the two bonding systems decreased after contamination. Re-priming restored the MSBS to control values, while re-etching did not. Rinsing and re-priming produced a reduction in MSBS, and rinsing and re-etching did not increase the MSBS.

SIGNIFICANCE

The conditioning and saliva contamination changed the pH value of dentin surface. The MSBS decreased after contamination; however, re-priming with SE Bond primer was an adequate treatment to restore the bond strength.

Effect of water and saliva contamination on shear bond strength of brackets bonded with conventional, hydrophilic, and self-etching primers

This study assessed the effect of water and saliva contamination on the shear bond strength and bond failure site of 3 different orthodontic primers (Transbond XT, Transbond Moisture Insensitive Primer, and Transbond Plus Self Etching Primer; 3M Unitek, Monrovia, Calif) used with a light-cured composite resin (Transbond XT). Bovine permanent mandibular incisors (315) were randomly divided into 21 groups (15 in each group). Each primer-adhesive combination was tested under 7 different enamel surface conditions: (1) dry, (2) water application before priming, (3) water application after priming, (4) water application before and after priming, (5) saliva application before priming, (6) saliva application after priming, and (7) saliva application before and after priming. Stainless steel brackets were bonded in each test group with composite resin. After bonding, all samples were stored in distilled water at room temperature for 24 hours and then tested for shear bond strength. Noncontaminated enamel surfaces had the highest bond strengths for conventional, hydrophilic, and self-etching primers, which produced the same strength values. In most contaminated conditions, the self-etching primer had higher strength values than either the hydrophilic or conventional primers. The self-etching primer was the least influenced by water and saliva contamination, except when moistening occurred after the recommended 3-second air burst. No significant differences in debond locations were found among the groups bonded with the self-etching primer under the various enamel conditions.

In vivo evaluation of a moisture-activated orthodontic adhesive: a comparative clinical trial

OBJECTIVES

To evaluate and compare the clinical performance of a water-activated, ethyl-cyanoacrylate adhesive to a conventional composite resin. The null hypothesis tested was that there was no difference in bracket survival distribution, over a period of orthodontic treatment, for brackets bonded with either bonding agent.

DESIGN

Single center randomized controlled clinical study.

SETTING AND SAMPLE POPULATION

Twenty-five consecutive patients (15 females and 10 males) were selected and treated with fixed appliances in a university postgraduate orthodontic clinic. All teeth, but the molars, were bonded with twin stainless steel brackets (n = 429) using a split-mouth technique and random allocation of the two adhesives.

OUTCOME MEASURE

Bond failure rates during a period of 9 months were estimated for each adhesive system and the corresponding bracket survival curves were plotted using the Kaplan-Meier product-limit estimate. Bracket survival distributions with respect to adhesive material, tooth location, investigator, and bond failure interface were then compared by means of a log-rank test. Bond failure interface was determined using the Adhesive Remnant Index (ARI).

RESULTS

The water-activated bonding material recorded a significantly higher bond failure (22.4%) than the composite resin (5.1%). There were also statistically significant differences in bracket survival distributions between the two adhesives (log-rank test: p < 0.001). Premolars exhibited higher bond failure rates than incisors and canines (p < 0001). The predominant mode of failure was within the bonding material.

CONCLUSION

Further investigations focused on the improvement of the physical and mechanical properties of the water-activated bonding system are needed to make it a reliable alternative adhesive for the direct bonding of orthodontic brackets.

An 18-month clinical study of bond failures with resin-modified glass ionomer cement in orthodontic practice

The purpose of this study was to evaluate, over an 18-month period, the clinical performances of a resin-modified glass ionomer cement for bonding orthodontic brackets and to analyze various factors that influenced their survival and failure rates. Two orthodontists using the edgewise technique participated in this study; 6113 brackets, including 20 molar tubes, were bonded with Fuji Ortho LC (GC, Europe, N.V. Leuven, Belgium) in 135 patients. Ceramic, metal, and resin brackets were tested, and both operators used the same bonding method for the brackets. The survival rate and the failure rate of the brackets were evaluated. The rates were determined by operator, bracket type, tooth position in the dental arch, and age and sex of the patients. Bracket survival rates were estimated using the Kaplan-Meier test. The Cox-Mantel statistical test with a level of significance set at 0.05 was used to compare survival curves. The chi-square test was used at a level of P < .05 to compare failure rates. The overall failure rate for the sample was 7%, and the overall survival rate was equal to 0.918. Age had no significant influence on the failure rate (P = .07); however, it had a significant influence on the survival rate (P < .01). The best survival rates were obtained in the groups aged 16 to 20 years (S[t] = 0.943) and older than 20 years (S[t] = 0.929). The difference between males and females was not statistically significant in terms of failure rate (P = .17). However, the Cox-Mantel test showed a higher bracket survival rate for the males (S[t] = 0.924) than for the females (S[t] = 0.839) (P < .00001). The influence of the operator was not statistically significant on the failure rate (P = .08); however, it was significant on the survival rate (P < .0002). Location in the arch had a significant influence on the failure and survival rates. The worst results were obtained in the upper incisors and the canines, and the best results in the lower premolars. Fifteen percent of the molar tubes failed; their survival rate was equal to 0.833. The failure rate was significantly greater for resin brackets than for metal or ceramic brackets (P = .007). The highest survival rate was obtained with ceramic brackets (P = .0001). This in vivo study showed that bonding brackets and molar tubes with Fuji Ortho LC is compatible with clinical orthodontic practice.

The bonding of composite resin to moist enamel

OBJECTIVE

To determine the effect on the bond strength of modern dentine bonding agents to etched enamel of surface contamination with water.

DESIGN

Fifteen bond strength measurements were made for bonds prepared to both moist and dry etched enamel for each of three test and one control materials.

RESULTS

For two materials (Scotchbond 1 and Prime and Bond 2.1) the bond strength was not affected by the presence of water on the etched enamel surface. A mean bond strength in excess of 25 MPa was achieved for both materials under all conditions. One material (Optibond Solo) showed a 30% increase in bond strength when bonds were formed under wet condition (21.10 MPa compared with 15.35 MPa). The bond strength of the control material, a conventional unfilled bonding resin, decreased markedly with aqueous contamination (9.14 MPa compared with 26.75 MPa).

CONCLUSION

Etched enamel should be rehydrated routinely prior to bonding composite resin to its surface using a water displacing dentine bonding system.