Journal of Conservative Dentistry
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JOURNAL REVIEWS Table of Contents   
Year : 2009  |  Volume : 12  |  Issue : 3  |  Page : 129
Journal Reviews


Department of Conservative Dentistry & Endodontics, Meenakshi Ammal Dental College, Maduravoyal, Chennai - 600095, India

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Date of Web Publication7-Nov-2009
 

How to cite this article:
Bharadwaj A, Alberqueque D. Journal Reviews. J Conserv Dent 2009;12:129

How to cite this URL:
Bharadwaj A, Alberqueque D. Journal Reviews. J Conserv Dent [serial online] 2009 [cited 2019 Apr 21];12:129. Available from: http://www.jcd.org.in/text.asp?2009/12/3/129/57638
Mechanical properties of experimental dental composites containing a combination of mesoporous and nonporous spherical silica as fillers

Samuel SP, Li S, Mukherjee I, Guo Y, Patel AC, Baran G, Wei Y

Mesoporous fillers have been investigated for use in dental composites because of their potential for creating micromechanical filler/resin matrix interphase bonding. The resin monomers are forced into the pores of these fillers before polymerization (by high pressure or vacuum). This enables mechanical interlocking between the filler particles and the resin matrix in the cured polymer. In the case of micromechanical bonding, dental polymer chains are threaded mechanically (like a "necklace") through nanosized channels in the fillers. This could eliminate the need for the silane treatment of fillers for interfacial chemical bonding that is prone to hydrolysis in the oral environment. For the study, a combination of mesoporous silica, which was synthesized using the non-surfactant templating method, and nonporous spherical silica (500nm) was used to prepare experimental dental composites to overcome the filler loading limitations of high surface area mesoporous fillers. The porous silica used in this study contained interconnected pores and channels as opposed to porous fillers containing surface pores (SolitaireTM). These composites were evaluated for compressive strength, compressive modulus, flexural modulus, and flexural strength. The results showed that composites containing a combination of mesoporous and nonporous fillers have better mechanical properties than the composites having either of these fillers alone and comparable mechanical properties to SolitaireTM. The mechanical properties were not measured after storing the composites in water for a prolonged period of time. The results showed that a combination of mesoporous and nonporous materials can be used to prepare stronger dental materials that may resist hydrolysis and wear.

Dent Mater. 2009 Mar;25(3):296-301.

High-strength CAD/CAM-fabricated veneering material sintered to zirconia copings-a new fabrication mode for all-ceramic restorations

Beuer F, Schweiger J, Eichberger M, Kappert HF, Gernet W, Edelhoff D

A new fabrication mode for all ceramics is introduced in this study, wherein an anatomically shaped lithium disilicate veneer cap is fabricated with CAD/CAM and sintered to the zirconia-based core. This in vitro study compared the fracture strength of zirconia-based crown copings, being veneered with the newer sintering technique or either overpressed or veneered by the layering technique for completion. A 1.2mm, 360΀ chamfer preparation was performed on a second maxillary molar and was dublicated 15 times in a cobalt-chromium-alloy. A sample of 45 zirconia copings was produced and divided into three groups with CAD/CAM method. In the first group (VT) zirconia copings received conventional veneering in layering technique, in the second group the veneering porcelain was pressed over the zirconia coping (PT), and for the third group (ST) the fabricated veneering cap was sintered onto the zirconia coping. All crowns were cemented conventionally onto their dies and tested in the universal testing machine at a crosshead speed of 0.5mm/min until clinical failure. The fracture load data were compared by a one-way analysis of variance and a multiple comparison posthoc test (a<0.05). Results showed that specimens from group VT showed a mean (S.D.) fracture load of 3700.39 (1238.72) N, group OT 3523.73 (1181.11) N and group ST 6262.67 (2257.42) N. The fracture load of group ST were significantly greater than groups VT/OT (P<0.001). The new CAD/CAM-fabricated bilayered restorations (ST) were superior to the present techniques (VT and OT) in terms of fracture load. The CAD/CAM method provides the advantages of using high quality material with a minimum of flaws and also significantly reduces the fabrication time in comparison with the other techniques. The sintering technique (ST) offers the possibility to produce cost-effective crowns and fixed partial dentures with a potential lower risk of chippings and thus could enhance the clinical reliability of zirconia-based restorations.

Dent Mater. 2009 Jan;25(1):121-8.

Susceptibility of Candida albicans and  Enterococcus faecalis Scientific Name Search itosan, Chlorhexidine gluconate and their combination in-vitro

NV Ballal et al

The medicaments were divided into three groups;

Group I Chlorhexidine gel, Group II chitosan gel, Group III Chlorhexidine + Chitosan gel; these medicaments were used against Enterococcus faecalis (ATC 24212) and Candida albicans (ATCC 24433). The organisms were used to make the lawn culture on sabouraud's dextrose agar and blood agar plates respectively. Wells were prepared in these lawn cultures and filled with 2% Chlorhexidine gel, 2% Chitosan gel and their combination. The agar plates were incubated overnight at 37΀C and the zone of inhibition was examined after 48 h. 2% Chlorhexidine gel in combination with 2% Chitosan gel has the highest antimicrobial effect against C. albicans and E. faecalis compared with 2% Chlorhexidine gel or 2% Chitosan gel alone. Factors like pH of substrate, incubation period, toxicity sensitivity and diffusion capacity of drug may have an impact on the antimicrobial activity of test material.

Aus Dent J 2009; 35:29-33.

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Correspondence Address:
Anuj Bharadwaj
Department of Conservative Dentistry & Endodontics, Meenakshi Ammal Dental College, Maduravoyal, Chennai - 600095
India
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Source of Support: None, Conflict of Interest: None


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