The comparative evaluation of fracture resistance and microleakage in bonded amalgam, amalgam, and composite resins in primary molars.

Background: The intense development of adhesive restorative materials and parents’ preferences for esthetic restorations prompt clinicians to use alternative restorative materials for primary molars. Amalgam, however, is the choice of material when it comes to occlusal stress bearing areas, either in primary or permanent molars. To overcome the drawbacks of amalgam and restorative adhesive materials, the bonded amalgam technique is employed. Aims: To evaluate microleakage and fracture resistance of bonded amalgam in primary molars, and compare it with the microleakage and fracture resistance of high‑copper amalgam and composite resin materials. Settings and Design: An in vitro study and 60 caries‑free primary molars were used. Subjects and Methods: A total of 60 samples were randomly divided into two equal groups for the evaluation of microleakage and fracture resistance. Class V cavities for microleakage study prepared on 30 samples and Class II mesio‑occluso‑distal cavities for fracture resistance study on other 30 samples were prepared and randomly divided into three equal groups. Group I received amalgam, Group II received bonded amalgam, and Group III received composite resins. The microleakage was viewed under a stereomicroscope. The fracture resistance was evaluated using a universal testing machine. Results: Bonded amalgam exhibited minimum microleakage, when compared to amalgam and composite resin and was found to be statistically insignificant (P = 0.203), while amalgam showed better fracture resistance compared to bonded amalgam and composite resin. It was found to be statistically insignificant (P = 0.144). Conclusions: Bonded amalgam appears to be comparable to amalgam when microleakage is considered and to composite resin when fracture resistance is considered; hence, bonded amalgam can also be an alternative material to amalgam in primary molars.

Microleakage of bonded amalgam restorations using different adhesive agents with dye under vacuum: An in vitro study.

Aim: In an effort to minimize tooth preparation, yet provide additional retention to compromised tooth structure, bonded amalgam restorations were introduced. Various resin-based adhesives have been tried earlier under bonded amalgam restorations. Still there are controversies regarding the outcome of bonded amalgam restorations regarding their adaptability to the tooth structure and microleakage. Therefore, this study was undertaken to compare the microleakage of bonded amalgam restorations using different adhesive materials. Materials and Methods: Standard Class I cavities were prepared on occlusal surfaces of 60 human molars. Teeth (n=60) were divided into three groups according to the material employed, as follows: group I: amalgam with glass ionomer cement (GIC) (type I); group II: amalgam with resin cement (Panavia F 2.0) and group III: amalgam with Copalex varnish as a control. Following restoration, the teeth were submitted to thermal cycling. The teeth were subsequently immersed in 2% rhodamine B dye under vacuum for 48 hours and sectioned to allow the assessment of microleakage under stereomicroscope. Results: The values were tabulated and the results were statistically analyzed using analysis of variance (ANOVA), Tukey's post hoc test and Kruskal-Wallis test. Amalgam with type I GIC showed the least leakage with no statistically significant difference (P value 0.226) when compared to amalgam with Panavia F 2.0 and amalgam with varnish (P value 0.107). Conclusion: It can be concluded that bonded amalgam with type I GIC is a good alternative to amalgam with resin cement (Panavia F 2.0) and amalgam with varnish for large restorations, with the added advantages of GICs. Clinical Significance: Bonded amalgam restorations prevent over-preparation and reduce the tooth flexure. GIC type I under amalgam provides chemical bonding in between amalgam and tooth structure and thus reduces the microleakage.

Fracture resistance of crown-root fractured teeth repaired with dual-cured composite resin and horizontal posts / 대한치과보존학회지

The purpose of this study was to investigate the fracture resistance of crown-root fractured teeth repaired with dual-cured composite resin and horizontal posts. 48 extracted human premolars were assigned to control group and three experimental groups. Complete crown-root fractures were experimentally induced in all control and experimental teeth. In the control group, the teeth (n=12) were bonded with resin cement and endodontically treated. Thereafter, the access cavities were sealed with dual-cured composite resin. In composite resin core - post group (n=12), the teeth were endodontically treated and access cavities were sealed with dual-cured composite resin. In addition, the fractured segments in this group were fixed using horizontal posts. In composite resin core group (n=12), the teeth were endodontically treated and the access cavities were filled with dual-cured composite resin without horizontal posts. In bonded amalgam group (n=12), the teeth were endodontically treated and the access cavities were sealed with bonded amalgam. Experimental complete crown-root fractures were induced again on repaired control and experimental teeth. The ratio of fracture resistance to original fracture resistance was analyzed with Kruskal-Wallis test. The results showed that teeth in control and composite resin core - post group showed significantly higher resistance to re-fracture than those in amalgam core group (p < 0.05). The resistance to refracture was high in the order of composite resin - post group, control group, composite resin group and bonded amalgam group. Within the scope of this study, the use of horizontal post could be beneficial in increasing the fracture resistance of previously fractured teeth.

Teeth fracture resistance in bonded amalgam restorations using different adhesive materials / 实用口腔医学杂志

Objective:To evaluate the effects of resistance of bonded amalgam restorations to fracture after treatment.Methods: Fifty healthy extracted maxillary teeth were selected,ten of them as control.The remainder were prepared a mesial occlusal distal(MOD) cavity.All of the teeth were then divided into five groups: 1st group: control;2nd group: direct restoration;3rd group: Luting;4th group: GC Fuji Ⅱ;5th group: RelyX ARC.All specimens were placed in a 37 degree centigrade humidity chamber for 72 h.The samples were thermocycled for 2 500 cycles at a temperature of 5 ℃ and 55 ℃.The samples use fatigue testing and observe by scanning electron microscope.Results:The preparation and restoration groups required significantly less force to fracture than the control group.The group with glass-ionomer cement bonding and composite resin bonding showed no significantly fracture resistance.Conclusion:Bonded amalgam restoration is a effective technique.At the same time glass-ionomer cement bonding and composite resin bonding shows no significantly fracture resistance.

Efeito de um sistema adesivo e de um cimento de ionômero de vidro modificado por resina na resistência ao cisalhamento do amálgama aderido à dentina de dentes decíduos e permanentes / Effect of adhesive and glass ionomer cement on shear bond strength of amalgam bonded to primary and permanent dentin

A união do amálgama de prata à dentina de dentes decíduos e permanentes, usando dois diferentes agentes de união, um cimento de ionômero de vidro modificado por resina (Fuji II LC Improved) e um sistema adesivo (Scotchbond Multi-Uso Plus) foi analisada através do ensaio de cisalhamento. O esmalte de superfície oclusal de molares decíduos e permanentes foi removido. Em metade das amostras, a dentina foi condicionada com ácido fosfórico à 35% por 15 segundos nos permanentes e 7 segundos nos decíduos, e após o sistema adesivo colocado. A outra metade, foi condicionada com ácido poliacrílico à 20% por 10 segundos e após uma camada de cimento de ionômero de vidro colocada.Antes da polimerização do adesivo e da geleificação do ionômero, amálgama de prata foi condensado no interior de uma matriz de aço inoxidável. Após 24 horas as amostras foram termocicladas e, então, submetidas ao ensaio de cisalhamento após 6 dias, a uma velocidade de 1mm/min. Após análise estatística dos resultados, foi verificado não haver diferença significante nos grupos onde o sistema adesivo foi usado, enquanto que diferença significante foi observada entre dentes decíduos e permanentes quando o agente de união foi o cimento de ionômero de vidro, apresentando esses últimos dentes resultados superiores. Observando as falhas em microscopia óptica, verificou-se que, nos dentes permanentes, elas ocorreram principalmente na interface agente de união/amálgama. Nos dentes decíduos, independente do material, as falhas ocorreram tanto na interface agente de união/amálgama como na interface agente de união/dentina

The shear bond strength of dental amalgam bonded to dentin of primary and permanent teeth was evaluated when an adhesive (Scotchbond Multi Purpose Plus) and a glass ionomer cements (Fuji II LC improved) were used as lining. The occlusal surface enamel of 20 second primary molars and 20 tirth permanent molars was removed, the lining was applied on dentin and the amalgam condensed in a matrix. Twenty-four hours late, the specimens were submitted to the termocycled, and six days later, they were submitted to the shear bond strenght, at a crosshead speed of 1mm/minute. Results showed no significant difference when the lining was the adhesive. When the glass ionomer cement was used as lining, statistical difference was observed between primary and permanent teeth where the better. In permanent teeth the failures occurred in the lining/amalgam interface and in primary teeth the failure occurred either in the lining/amalgam interface and or lining/dentin interface