Shear bond strength of bis-acryl composite provisional material repaired with flowable composite

Background : Time and expense are considerable when refabrication of a bis-acryl composite provisional prosthesis is required, so an effective method of repair is desirable. Attempts at self-repair have been ineffective, and no reports of repair specific to bis-acryl composites were found in the literature.
Purpose : To investigate the strength of a bis-acryl composite repair using flowable composite after two surface treatments and three storage conditions.
Materials and Methods : Thirty specimens of bis-acryl composite were made and divided into six groups. Half of the specimens received air abrasion only, and half received air abrasion followed by application of an intermediate bonding resin. A flowable composite was then applied to all specimens. Following three different storage conditions, the flowable composite was debonded using a universal testing machine in tensile mode.
Results : All specimens failed cohesively within the bis-acryl composite rather than at the repair interface. Surface treatment with air abrasion alone resulted in significantly higher shear bond strength values than when air abrasion and intermediate bonding resin were combined. Bond strength values were significantly higher in thermocycled specimens than in air-dried specimens.
Conclusions : Use of air abrasion followed by application of flowable composite proved to be a successful technique for bis-acryl composite repair.     

Clinical evaluation of a flowable resin composite and flowable compomer for preventive resin restorations

This clinical study evaluated the retention and caries protection of a flowable resin composite (Flow Line) and a flowable compomer (Dyract Flow) used in preventive resin restorations as compared to the conventional preventive resin technique which uses a resin composite (Brilliant) and a sealant (Concise). This study observed 205 permanent molars with small carious cavities less than 1.5 mm in width, which were obtained from 165 children aged 7 to 15 years. Flowable resin composite was used to treat 75 teeth, and 71 teeth were treated with flowable compomer in both cavities and caries-free fissures. For the control group, 59 teeth were treated with resin composite in cavities and sealant in caries-free fissures. The teeth were evaluated at 3, 6, 12, 18 and 24-month intervals. After three months, all 205 treated teeth were completely intact. After six months, 66 of the 71 teeth treated with flowable resin composite and 65 of the 70 teeth treated with flowable compomer were complete, compared to 57 of the 58 teeth treated with the conventional preventive resin technique. After 12 months, 60 of the 67 teeth treated with flowable resin composite and 61 of the 67 teeth treated with flowable compomer were complete, compared to 51 of the 55 teeth treated with the conventional preventive resin technique. After 18 months, 53 of the 61 teeth treated with flowable resin composite and 54 of the 62 teeth treated with flowable compomer were complete, compared to 47 of the 53 teeth treated with the conventional preventive resin technique. After 24 months, 49 of the 58 teeth treated with flowable resin composite and 45 of the 57 teeth treated with flowable compomer were complete, compared to 42 of the 52 teeth treated with the conventional preventive resin technique. There were no statistically significant differences in retention rates among all groups after 3, 6, 12, 18 or 24-months (p>0.05). One tooth treated with flowable resin composite and one tooth treated with flowable compomer developed caries after 18 and 24 months, respectively, resulting from partial loss at "caries-free fissures." Five teeth developed caries in the conventional preventive resin group; one after 12 months, two after 18 months and one after 24 months, due to loss at cavities. The final caries occurred after 24 months, resulting from partial loss at "caries-free fissures." The differences in caries development among the three groups were not statistically significant (p>0.05). This study suggested that flowable resin composite and flowable compomer could be used for preventive resin restorations. Meanwhile, a vigilant recall should be followed-up due to the risk of failure for flowable materials in "caries-free" fissures. The repair should be performed immediately, in case the preventive resin restoration develops a fracture or loss.     

流动性充填材料用于预防性树脂充填的实验研究

目的　以传统的复合树脂+窝沟封闭剂的方法为对照组,用体外实验的方法评价流动树脂、流动复合体在预防性树脂充填(preventiveresinrestoration ,PRR)治疗中的情况。方法　患小面积龋被拔除第三恒磨牙9颗,分别用流动树脂(A组)、流动复合体(B组)和传统的复合树脂材料+窝沟封闭剂(C组)的方法进行PRR治疗。5 0 %AgNO3 浸染法检查微渗漏;用SEM观察树脂与牙齿的结合情况。结果　①渗透实验表明各实验组和对照组中均存在一定程度的微渗漏;在微渗漏率方面,A组低于对照的C组(P <0 .0 5 ) ,在树脂渗透率方面A组低于B组和C组(P <0 .0 5 )。②SEM上显示A与B组相似,多数标本树脂与牙齿接触的界面上有结合良好的树脂突样结构,但树脂在和窝沟底部与牙体组织结合较差,特别在极细窝沟处;C组中结合良好的界面所占比例较少,复合树脂勉强压入窝洞后充填不实,在沟底部常见宽大裂纹。结论　在流动复合体和流动树脂在PRR治疗时更适用于沿窝沟走向侵润的窄长形态的窝沟内龋,而传统PRR法更适用于单个龋损直径在1 .5～2mm左右的圆形或卵圆形的小面积龋,流动性充填材料在PRR治疗中可作为传统法的一种补充,最大限度地保留健康牙体组织。     

Repair of defective Class I composite resin restorations

Composite resin restorations undergo dimensional changes that can eventually result in marginal defects. Unlike silver amalgam restorations, which usually should be completely removed before the tooth is restored again, bonded composite resin restorations can often be repaired. This report demonstrates a step-by-step technique for repairing a defective Class I composite resin restoration with a new application of resin after elimination of the defect. The method has proved successful over the last 8 years.     

Fabrication of provisional acrylic resin restorations

A technique for transitional restoration fabrication has been described. It permits modifications of existing axial and occlusal tooth contours to be accurately reproduced in transitional restorations.     

流动型树脂衬洞对可压型树脂充填Ⅰ类洞微渗漏的影响

目的研究流动型树脂衬洞对两种可压型树脂充填Ⅰ类洞微渗漏的影响。方法 48颗健康离体磨牙制备Ⅰ类洞。样本随机分为TBF组(Tetric N-Cream Bulk Fill)、P60水平组(Filtek P60)、P60斜形组(Filtek P60),每组16颗,每组再分别分为2小组:一组用流动树脂衬洞,另一组不衬洞。将充填完成的样本置于2%亚甲基蓝溶液中浸泡24 h后,经修复体中央沿颊舌向剖开,体视显微镜下观测染料浸入的深度,并进行统计学分析。结果使用流动树脂衬洞的TBF组和P60斜形组微渗漏最小,较其他组差异有统计学意义,两组间差异无统计学意义。结论流动树脂衬洞可以减小树脂充填后的微渗漏,使用瓷化纳米大块树脂充填比P60斜形分层充填更节省操作时间,可获得与P60斜形分层充填术相当的边缘封闭性。     

Reinforced heat-processed acrylic resin provisional restorations

A technique has been described for the fabrication of strong, esthetic, and periodontally considerable provisional restorations. The technique involves cast nonprecious metal frameworks and heat-processed acrylic resin.     

In vivo interfacial adaptation of class II resin composite restorations with and without a flowable resin composite liner

The aim of this study was to evaluate in vivo the interfacial adaptation of class II resin composite restorations with and without a flowable liner. In 24 premolars scheduled to be extracted after 1 month, 48 box-shaped, enamel-bordered class II cavities were prepared and restored with a flowable liner (FRC, Tetric Flow/Tetric Ceram/Syntac Single-Component) or without (TRC), cured with three different curing modes: soft start and 500- or 700-mW/cm² continuous irradiation. Interfacial adaptation was evaluated by quantitative scanning electron microscopic analysis using replica method. Gap-free adaptation in the cervical enamel (CE) was observed for FRC and TRC in 96.2 and 90.2%, for the dentin (D) in 63.6 and 64.9%, and for occlusal enamel (OE) in 99.7 and 99.5%, respectively. The difference between the two restorations was not statistically significant (ns). Significant better adaptation was observed for OE than CE and D (p<0.01), and for CE than D (p<0.01). Gap-free adaptation with the soft-start and 500- and 700-mW/cm2 continuous-curing modes was observed for CE: 88.7%, 92.7%, 97.9% (ns); OE: 99.8%, 98.7%, 100% (ns); and D: 64.0%, 63.9%, and 64.6% (ns), respectively. It can be concluded that neither the use of flowable resin composite liner nor the curing mode used influenced the interfacial adaptation.     

Leakage pathway of Class V cavities restored with different flowable resin composite restorations

This study investigated the leakage pathway of facial and lingual Class V cavities restored with different flowable resin composites bonded with one bonding agent by examining the resin/dentin interface. Forty Class V cavities were etched with 37% phosphoric acid gel; Single Bond dental adhesive was applied, then the cavities were randomly divided into four groups (n=10). Three groups were restored with one of three flowable resin composites (Grandio Flow, Filtek Flow and Admira Flow). The fourth group was restored with Z250 (hybrid resin composite) to serve as a control. The specimens were then placed in 50% w/v silver nitrate solution for 24 hours and immersed in a photodeveloping solution for eight hours. Thereafter, the specimens were sectioned bucco-lingually, polished, mounted on stubs, gold sputter coated and examined by scanning electron microscope. Silver particle penetration length with and without gap formation was measured directly on the scanning electron microscope monitor and calculated as a percentage of the total length of the cut dentin surface that was penetrated by silver nitrate. The data were analyzed with one-way ANOVA and Tukey HSD test. The groups restored with Filtek Flow and Admira Flow showed a microleakage pattern where silver nitrate penetration was observed with gap formation at the tooth/restoration interface and Filtek Flow recorded significantly higher leakage than Admira Flow. Grandio Flow showed similar marginal adaptation to Z250 resin composite with no gap formation at the interface. However, silver ions had penetrated beneath the resin-impregnated layer in cavities restored with Grandio Flow and Z250, indicating nanoleakage occurred. This study suggests that volumetric shrinkage in resin composites remains a problem. Although some new technologies are trying to solve the problem of composite shrinkage, the bonding system used in this study did not achieve perfect sealing at the restoration/dentin interface. This might affect durability of the bond to dentin.     

The effect of an intermediate layer of flowable composite resin on microleakage in packable composite restorations

OBJECTIVES: The aim of the present study was to evaluate the effect of a thin layer of flowable composite on microleakage in Class II direct packable composite resin restorations on young permanent teeth in vitro. METHODS: Twenty sound human premolars and molars extracted for orthodontic reasons were selected for this study. The teeth were randomly assigned into two groups of 10 teeth each (groups A and B). Class II cavities were prepared as uniformly as possible in the mesial and distal aspects of each tooth. The gingival margin extended apically approximately 0.5 mm beyond the cemento-enamel junction, in the dentin. Cavities in group A were restored with packable composite and Alert/Flow-it flowable composite, while groups B cavities were restored with Pyramid/Aeliteflo. The control cavities in groups A1 and B1 were restored with only packable composite. The teeth were immersed in 2% methylene blue solution for 24 h to allow dye penetration into possible existing gaps between the tooth substance and the restorative material. All teeth were subjected to thermocycling. RESULTS: The dye penetration ranged between 6.6 and 7.2 mm. No significant difference was found between the control and the experimental groups. CONCLUSION: The use of flowable composite resin as intermediate material does not reduce microleakage.     

Construction of accurate acrylic resin provisional restorations

A technique has been described for making accurate fitting acrylic resin provisional restorations with attention to marginal adaptation and ease of fabrication.     

The effect of flowable resin composite on microleakage and internal voids in class II composite restorations

This in vitro study evaluated the influence of two flowable resin composites on marginal microleakage and internal voids in Class II composite restorations with the margins below the cementoenamel junction (CEJ). Class II cavities randomly divided into four groups: Group I-Filtek with Filtek Flow lining; Group II-Filtek; Group III-Tetric Ceram with Tetric Flow lining; Group IV-Tetric Ceram. After thermocycling tests (5-60 x 1500) and dye soaking, the teeth were sectioned in a mesiodistal direction along their longitudinal axis. Gingival-marginal microleakage and internal voids in three separate portions of the restoration (interface, cervical and occlusal voids) were observed with a microscope. Statistical analyses indicated that the use of flowable resin composites (Groups I and III) provided a reduction in marginal microleakage and a reduction in some parts of the internal voids or total voids (p<0.05). The condensable material (Filtek) in combination with the flowable liner showed fewer voids (interface, occlusal, total) than the hybrid resin (Tetric) (p<0.05). There was a correlation between the number of internal voids or total voids and the marginal microleakage (p<0.05). It was concluded that a composite lining in a Class II resin composite with margins below the cementoenamel junction may reduce marginal microleakage and voids in the interface and the total number of voids in the restoration.     

Bonding and sealing ability of a new self-adhering flowable composite resin in class I restorations

Objectives

The aim of this study is to assess by means of shear bond strength tests (SBS), microleakage analysis (μLKG), and scanning electron microscopy (SEM) the bonding potential and sealing ability of a new self-adhering composite resin.

Materials and methods

SBS and μLKG of Vertise Flow (VF, Kerr) were measured and compared to the all-in-one adhesive systems G-Bond (GB, GC), AdheSE One (AO, Ivoclar Vivadent), Adper Easy Bond (EB, 3M ESPE), Xeno V (XV, Dentsply), and iBOND (iB, Heraeus Kulzer). For each system, 20 molars were tested for SBS on dentin (n?=?10) and enamel (n?=?10). For μLKG assessment, 12 premolars per group were selected and small, box-shaped cavities were made. After restoration, the teeth were immersed in 50 wt% silver nitrate solution for 24 h. For each group, 10 randomly selected specimens were processed for leakage calculations, while two of the specimens were examined under SEM. Between-group differences in SBS to dentin and μLKG were assessed using Kruskal–Wallis analysis of variance followed by the Dunn’s Multiple Range test. Enamel SBS data were analyzed with one-way ANOVA, followed by the Tukey test.

Results

On dentin and enamel, VF recorded the lowest SBS values that were statistically comparable to those measured by GB, iB, and AO. μLKG analysis showed the lowest percentage of stained interface for VF. Significantly greater extent of infiltration was seen for iB and EB.

Conclusions

Although VF resulted in lower bond strengths values on either dental substrate, better marginal sealing ability was visualized in comparison with all-in-one adhesive systems.

Clinical relevance

The results of the present study demonstrated satisfactory in vitro outcome of the self-adhering flowable composite resin VF when used to restore class I cavities.     

Composite restorations: influence of flowable and self-curing resin composite linings on microleakage in vitro

This in vitro study evaluated the microleakage at enamel (occlusal) and dentin (gingival) margins of MOD resin composite restorations made with different incremental insertion techniques. MOD cavities were prepared on 60 extracted human molars with the proximal margins placed 1 mm below the cemento-enamel junction. All teeth were acid-etched and treated with One-Step adhesive, then restored with a hybrid resin composite (Renew) with and without a flowable composite (AEliteflo) or a self-curing composite (Bisfil 2B) as the first increment in the proximal boxes. The time of placement of the second increment in relation to curing of the first increment was also varied. After polishing, the teeth were soaked in 0.5% basic fuchsin for 24 hours, sectioned and evaluated for dye penetration. None of the restorative techniques prevented microleakage at the enamel and dentin margins. However, microleakage at dentin margins were significantly reduced by the use of a flowable composite as the first increment in the proximal boxes. Time of placement in relation to curing had no influence on microleakage. Microleakage was lower at enamel margins than at dentin margins; however, besides microleakage at the enamel-restoration interface, 37 of the 60 restored teeth (62%) displayed at least one white line in enamel adjacent to the composite restoration.     

Influence of flowable composite lining thickness on Class II composite restorations

This in vitro study aimed to investigate the influence of flowable composite lining with different thicknesses on the marginal quality and internal porosity of Class II composite restorations. Thirty-two intact molars, each prepared with two box-only Class II cavities, were randomly divided into four groups: Group 1, P60 filling alone; Group 2, ultrathin flowable composite lining/co-cured with overlaying composite; Group 3, thin lining/pre-cured and Group 4, thick lining/pre-cured. The teeth were then thermocycled for 1500 cycles (between 5 degrees C and 60 degrees C) and dye immersed for 24 hours. Exterior surface replicas of these restorations were fabricated before and after thermocycling and examined by SEM to evaluate percentages of the five marginal patterns. Data was statistically evaluated using one-way ANOVA test. The teeth were subsequently sectioned longitudinally. The interface microleakage of cervical margin was measured as to the extent of dye penetration. Internal voids were separately recorded in the cervical interface and the cervical and occlusal halves of the restorations. Mann-Whitney test was applied to analyze the interface microleakage and internal voids. Results revealed that replicas of Group 4 presented the highest percentage of marginal openings both before and after thermocycling in SEM examination. Group 2 exhibited superior marginal quality in interface microleakage evaluation compared to the other groups, while Group 4 exhibited the worst. The pre-cured groups (Group 3 and 4) showed significant reduction in interface and cervical voids. Despite the reduction in interface voids, a thick lining may impair the marginal sealing, especially after thermocycling. It was concluded that a minimally thin flowable composite lining improved cavity adaptation and marginal sealing.