Antimicrobial-peptide coating that ruptures the wall of Gram positive bacteriaDental Materials

About

Authors
X. Chen, H. Hirt, Y. Li, S.-U. Gorr, C. Aparicio
Year
2014
DOI
10.1016/j.dental.2014.08.177
Subject
Mechanics of Materials / Materials Science (all) / Dentistry (all)

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e86 dental mater ials 3 0 S ( 2 0 1 4 ) e1–e180 for surgery. The introduction of adhesive luting procedures further reduced the invasive preparation, as it led to a strengthening of the cusps. As far as esthetic is concerned, fiber-reinforced IFPDs or all-ceramic IFPDs clearly performbetter than metal-ceramic IFPDs, but the clinical validation of these relatively new materials is still partial.

Methods and materials: A total of 43 IFPDs were prepared.

The boxes for IFPDs were performed with diamond burs for inlay preparation according to the following guidelines: 2.5mm occlusal depth (floor of isthmus to central groove); 3-mm vestibular-palatal/lingual width of the intercuspal isthmus; 2-mm depth of proximal box (shoulder with rounded internal angle); 4.5-mm buccal vestibular width (3mm of zirconia frameworkand0.5–0.6mmof ceramic veneering for each side); minimumdimensions of connectors 3mm× 3mm; inclusions of cusps in the preparation when the abutment tooth had a wide bucco-oral defect (>50%) or had been devitalized; divergence angle of the cavity of approximately 6 degrees. All

Zirconia frameworksweremilled frompre-sintered blocks (IPS e.max®ZirCAD for inLab Blocks B 40 L, Ivoclar Vivadent) and then overpressed with a dedicated ceramic (ZirPress, Ivoclar

Vivadent), througha lost-wax technique; the restorationswere than luted with a composite material.

Results:During the time of the follow-up no IFPD showed a framework fracture, 2 were subjected to minor chippings and could be repaired intraorally, one underwent a delamination and in 2 cases a debonding occurred. An overall survival rate of 95.3% was calculated.

Conclusion: The use of IFPDs represents a valid alternative to implant surgery in case of single missing teeth, also allowing for a reduced tooth structure removal if compared to conventional preparations for FPDs. Within the limits of this study, the use of a zirconia framework brings resistance to the

IFPD, and the press-on ceramic makes a completely adhesive luting technique possible, thus possibly enhancing the long term stability of the restoration. Nonetheless, more research and longer follow-ups are needed to assess the reliability of this technique. http://dx.doi.org/10.1016/j.dental.2014.08.175 175

Biocompatibility of glass ionomer cements applied in deep cavities

D.G. Soares1,∗, F.G. Basso1, N.T. Sacono2,

A.P.D. Ribeiro3, J. Hebling1, C. A. De Souza

Costa1 1 Araraquara School of DentistryUniversity

Estadual Paulista, Brazil 2 Federal University of Goiás, Brazil 3 University of Brazilia, Brazil

Purpose: To evaluate the response of human pulps after application of two categories of resin-modified glass-ionomer cements (RMGICs) as liners in deep cavities.

Methods & Materials: Deep Class V cavities were prepared in sound premolars scheduled to be extracted for orthodontics reasons (approved by Institutional Human Subjects Ethics

Committee) and the cavity floor was lined with Vitremer® (VT), Vitrebond® (VB) or Dycal® (DY – control). The liners were hand-mixed and clinically applied as recommended by the manufacturers. Only for VT, the cavity floor was pre-treated with a primer (polyacrylic acid+HEMA) for 30 s before application of this resin-based cement as liner. The cavities were then restored with adhesive system and composite resin.

Two sound teeth with no cavity preparation were used as control for the laboratorial process of the specimens. After 7 or 30 days the teeth were extracted (n=6), fixed, demineralized and processed for microscopic evaluation. The stained sections were scored according to the intensity of pulpal response (Mann–Whitney/Kruskal–Wallis, a=5%). The remaining dentin thickness (RDT) between the cavity floor and pulp tissue was measured.

Results:VT – 7 days (mean RDT=364.8m): Five specimens exhibited disruption of the odontoblastic layer associatedwith moderate to intense inflammatory response and inner dentin resorption in the pulp zone related to the cavity floor. One specimen presented no alterations on pulp tissue. VT – 30 days (mean RDT=381.0m): Three specimens exhibited no inflammatory pulp response, and the other 3 specimens presented slight to moderate inflammation and odontoblastic layer disruption. VB – 7 days (mean RDT=368.6m): Four specimens exhibited slight inflammatory response mediated by mononuclear cells and presence of a number of small congested blood vessels. Two specimens presented no inflammatory reaction. In all 6 specimens none to discrete tissue disorganization, characterized by disorganization of the odontoblast layer subjacent to the cavity floor, was observed. VB – 30 days (mean RDT=373.0m): Only one specimen presented mild inflammatory response and slight odontoblastic layer disorganization. DY/control – 7 and 30-day periods (mean

RDT=381.4m and 335.5m, respectively): All specimens exhibited normal pulp tissue with no inflammatory response or tissue disorganization.

Conclusion: The RMGIC Vitremer® applied in deep dentin pre-treated with primer caused the most intense damage to pulp tissue compared to Vitrebond®.

Keywords: Biocompatibility; Dental materials; Dental pulp http://dx.doi.org/10.1016/j.dental.2014.08.176 176

Antimicrobial-peptide coating that ruptures the wall of Gram positive bacteria

X. Chen, H. Hirt, Y. Li, S.-U. Gorr, C. Aparicio ∗

Minnesota Dental Research Center for

Biomaterials and Biomechanics, University of

Minnesota School of Dentistry, Minneapolis, USA

Purpose: Assessing the antimicrobial effects and prevention of biolfilm growth by an antimicrobial GL13K-peptide coating on Gram positive S. gordonii bacteria in a drip flow bioreactor. The culturing conditions in a drip flow bioreactor simulate more reliably the biological environment in the oral cavity; i.e., comparable shear forces to the ones exerted by saliva in contact with surfaces and biofilm and a sustained nutrition supply for the microflora. dental mater ials 3 0 S ( 2 0 1 4 ) e1–e180 e87

Fig. 1 – SEM images of S. gordonii biofilms grown on tested surfaces.