Fracture Resistance of Premolars Restored by Various Types and Placement Techniques of Resin Composites

Abstract

<jats:p>To verify the fracture resistance of premolars with mesioocclusodistal preparations restored by different resin composites and placement techniques. Sixty premolars were randomly divided into two groups based on type of composite resin: Filtek P60 or Nulite F, and then each group was separated into three subgroups: bulk, centripetal, and fiber insert according to the type of placement method (<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>n</mml:mi><mml:mo>=</mml:mo><mml:mn>10</mml:mn></mml:mrow></mml:math>). Single-bond adhesive system was used as composite bonding according to the manufacturer's instructions. Specimens were restored in Groups 1, 2, and 3 with Filtek P60 and in Groups 4, 5, and 6 with Nulite F. After being stored 24 hours at<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msup><mml:mn>37</mml:mn><mml:mo>∘</mml:mo></mml:msup></mml:math>C, a 4 mm diameter steel sphere in a universal testing machine was applied on tooth buccal and lingual cusps at a cross-head speed of 5 mm/min until fracture occurred. Groups 3 and 6 showed higher fracture resistance than Groups 1, 2, 4, and 5. Among the placement techniques, the fiber insert method had a significant effect, but the type of composite was ineffective. The insertion technique in contrast to the type of material had a significant influence on the fracture resistance of premolar teeth.</jats:p>

Influência do tratamento de superfície na resistência de união por cisalhamento de um cerômero indireto

“…No presente estudo foi utilizado o cerômero para restaurações indiretas BelleGlass (Kerr/Belle de Saint Claire). Segundo Touati (1996) e Moosavi et al (2012), é um material que necessita de mais avaliações quanto ao seu comportamento, para que possa se constituir em uma alternativa efetiva para restaurações indiretas. Apesar disso, segundo Itinoche et al (1999), a superioridade desses materiais (cerômeros) em relação aos demais, é atribuída ao fato de reunirem propriedades positivas das cerâmicas e das resinas compostas para restaurações diretas.…”

“…Apesar disso, segundo Itinoche et al (1999), a superioridade desses materiais (cerômeros) em relação aos demais, é atribuída ao fato de reunirem propriedades positivas das cerâmicas e das resinas compostas para restaurações diretas. Segundo Moosavi et al (2012), restaurações indiretas com cerômeros oferecem grande resistência à fratura comparáveis a dentes hígidos.…”

“…Segundo Van Meerbeek et al (1992), a polimerização do monômero no interior da dentina condicionada resultará na formação de uma camada intermediária uniforme, denominada camada híbrida (NAKABAYASHI et al, 1982(NAKABAYASHI et al, , 1991, transformando a estrutura dente/material restaurador em um corpo único, de tal forma que as forças aplicadas na superfície da restauração sejam gradualmente transferidas para estrutura do elemento dental sem causar fratura na restauração ou no dente. Ou seja, a introdução dos compósitos adesivos acabaram contribuíndo significativamente para a resistência à fratura dos dentes pois reforça a estrutura dentária (MOOSAVI et al, 2012), quando comparado a restaurações não adesivas (COELHO- DE-SOUZA et al, 2006;MONGA et al, 2009).…”

Nanoinformatics knowledge infrastructures: bringing efficient information management to nanomedical research

“…Indeed, in the case of nanomedicines, the development and approval of new drugs does not need to take so long and clinical trials are not necessarily vital in some cases, particularly when considering that nanomaterials are generally derived from drugs previously authorized by the U.S. Food and Drug Administration (FDA) (Etheridge et al 2013) or the European Medicines Agency (EMA) (Karalis and Macheras 2012). There are many drugs already approved or under commercial use, such as those for therapy against cancer—Daunoxome® (Petre and Dittmer 2007), Doxil® (Pearce et al 2012) and Caelyx® (Li et al 2012), among others—, bone substitutes such as CarriGen® 4 , dental composites such as FilTek® (Moosavi et al 2012), or platforms as the Verigene® System (Buxton 2009), which is extensively used in hospitals for diagnostic purposes. Considering the myriad of new and increasingly rapid results generated by nanomedical research nowadays, it is obvious that the development of new tools for managing all this information has become crucial for advancing the field.…”

Fracture Resistance of Various Bulk Fill Composite Resin in Endodontically Treated Class I Premolar (An in-Vitro Study)

“…Microleakage on the other hand causes deformation of the tooth structure, which leads to microcrack and eventually causes fracture. 8 Incremental technique is usually used in order to overcome this, but this technique requires special handling, more time and skills because the composite is applied layer by layer. Therefore, a new restorative material known as bulk fill resin based composites (RBSs), which can be applied in a single layer was introduced.…”