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Biomedical subjects

K Titley

Publications and source records attributed to K Titley.

11 recordsLinked to original sources
PubMed2005

Assessment of a novel alternative to conventional formocresol-zinc oxide eugenol pulpotomy for the treatment of pulpally involved human primary teeth: diode laser-mineral trioxide aggregate pulpotomy.

OBJECTIVE: The purpose of this study was to investigate whether a diode laser pulpotomy with mineral trioxide aggregate (MTA) sealing could be an acceptable alternative to the conventional formocresol pulpotomy and zinc oxide eugenol (ZOE) sealing in human primary teeth. METHODS: A randomized, single-blind, split-mouth study was used with a sample of 16 children aged from 3 to 8 years (mean age=5.10 years). A total of 26 pairs of teeth from these 16 patients were selected based on clinical and radiographic criteria. One tooth from each pair was randomly assigned to either the laser-MTA pulpotomy group or the formocresol-ZOE pulpotomy group. All teeth were followed up clinically and radiographically at 2.3, 5.2, 9.5 and 15.7 months. All extracted failures were sectioned and photographed to assess possible reasons for this. RESULTS: A total of seven laser-MTA-treated teeth were deemed to be radiographic failures (mean time until failure=9.1 months) compared to three formocresol-ZOE treated teeth (mean time until failure=12.5 months). These results were not significant using Fisher's exact test (P>0.05). Six of the laser-MTA failures and all three formocresol-ZOE failures exhibited furcal and/or periapical radiolucencies with or without pathologic root resorption. One of the laser-MTA failures displayed premature root resorption and is being observed for exfoliation. Analysis of photographs of teeth available for extraction revealed errors in clinical technique in addition to expected signs of a disease process such as the presence of granulation tissue and areas of pathologic root resorption. CONCLUSIONS: The laser-MTA pulpotomy showed reduced radiographic success rates compared to the formocresol-ZOE pulpotomy at 15.7 months; however, these results were not statistically significant. Improved success rates among a larger patient sample and a longer follow-up period would be required for the laser-MTA pulpotomy to be considered a routine alternative to the conventional formocresol-ZOE procedure. Meticulous restorative techniques must be followed to ensure the success of laser-MTA pulpotomies.

Aluminum Compounds↗
PubMed2001

Adhesion of glass-ionomer cement sealers to bovine dentin conditioned with intracanal medications.

This in vitro study assessed the adherence of glass-ionomer cement (GIC) root canal sealers to dentin conditioned by three endodontic intracanal medications. Three GIC sealers were used: (i) Ketac-Endo; (ii) KT-308, an experimental GIC sealer; and (iii) ZUT, a combination of KT-308 and a silver-containing zeolite (0.2% by weight). Superficial dentin of 120 bovine incisor crowns was used as a substrate. The dentin was irrigated with 2.6% NaOCI for 30 s and then blotted dry. One of the following conditioning media (n = 30) was maintained in contact with the dentin for 7 days: (i) Ca(OH)2 paste; (ii) chlorhexidine gluconate (CHX) liquid 0.12%; (iii) formocresol (FML) liquid; (iv) distilled water (dH2O) used as control. The GIC sealers were applied to the conditioned dentin, bench set for 90 min, stored in 100% humidity at 37 degrees C for 48 h, then tested to failure for shear bond strength (MPa) in an Instron machine. In the ZUT specimens, the shear bond strength did not differ significantly among those conditioned with Ca(OH)2, CHX, FML, and dH2O. For KT-308, the mean scores were significantly lower (p < 0.05) after conditioning with CHX than with dH2O. For Ketac-Endo, the mean scores were significantly lower after conditioning with Ca(OH)2 and FML than with dH2O (p < 0.05). Furthermore Ketac-Endo demonstrated significantly lower (p < 0.05) shear bond strength than KT-308 or ZUT to the dentin conditioned with Ca(OH)2 or FML. The results suggest that intracanal medications differentially influence the adhesion of various GIC sealers to root canal dentin.

Analysis of Variance↗
PubMed2001

Does single versus stepped curing of composite resins affect their shear bond strength?

BACKGROUND: Shrinkage occurs during polymerization of all resin composites, affecting not only the physical properties of the composites but also the marginal integrity of the restoration. Stepped photo-polymerization, in contrast to single-cure photo-polymerization, is said to minimize this shrinkage. The thickness of the increments of resin composite being cured may also be a factor in final shear bond strength. This study compared the shear bond strength resulting from these two curing methods with resin composites of various thicknesses. METHODS: Resin composite in increments of 1.5, 3 and 4.5 mm thickness, cured by stepped or single-cure photo-polymerization, was bonded to human third molar dentin with either the Scotchbond Multipurpose adhesive system or the Singlebond adhesive system. Each experimental group consisted of 12 specimens. After 7 days of storage in water, shear bond strength was tested to failure, and the mode of failure was recorded. RESULTS: The thickness of the resin composite and the method of curing had no significant effect on shear bond strength for bonds mediated by Scotchbond Multipurpose adhesive, but significantly lower shear bond strength was recorded for bonds mediated by Singlebond adhesive for resin composite 4.5 mm in thickness. With thicker resin composite, there was a tendency toward a greater proportion of adhesive cohesive bond failures. CLINICAL SIGNIFICANCE: The stepped photo-polymerization system of curing appears to offer no advantages over single-cure photo-polymerization, except that the former reportedly improves marginal adaptation and reduces marginal leakage. These results suggest that increments of resin composite to be cured by either method should be no thicker than 2 mm, particularly when the bond is mediated by a single-bottle adhesive.

Bisphenol A-Glycidyl Methacrylate↗
PubMed1999

The shear bond strength of glass ionomer cement sealers to bovine dentine conditioned with common endodontic irrigants.

AIM: The aim of this in vitro study was to evaluate the shear bond strength of commercially available and experimental glass ionomer cement (GIC) sealers to dentine exposed to common endodontic irrigants. METHODOLOGY: The enamel of 90 bovine incisor crowns, randomly divided into nine equal groups, was ground to expose the superficial dentine layer. The exposed surface was conditioned with either: (i) distilled H2O; (ii) 2.6% NaOCl; or (iii) 17% EDTA followed by 2.6% NaOCl. Five cc of each irrigant was applied over a 30-second period. The following GIC sealers were tested: (i) Ketac-Endo; (ii) KT-308, an experimental sealer; and (iii) ZUT, a combination of KT-308 and an antibacterial agent (0.2% by weight). The test sealers were applied to form cylinders with a standardized contact surface area (17.8 mm2) on the conditioned dentine surfaces. Specimens were bench set for 90 min and stored in distilled water at 37 degrees C for 48 h, then tested to failure for shear bond strength (MPa) in an Instron machine. RESULTS: KT-308 and ZUT had significantly higher MPa values than Ketac-Endo (two-factor ANOVA, P < 0.0001), regardless of the dentine conditioning. All specimens conditioned with 17% EDTA and 2.6% NaOCl combined had significantly lower MPa values than those conditioned with water or 2.6% NaOCl alone (P < 0.02). CONCLUSIONS: It was concluded that the experimental sealers KT-308 and ZUT bonded better to bovine dentine than Ketac-Endo, and that the bond of all three GIC sealers was better with the smear layer present.

Adhesiveness↗
PubMed1995

The composition and ultrastructure of resin tags in etched dentin.

PURPOSE: To examine in vitro the composition of resin tags in etched dentin by SEM and vital staining using Alcian Blue dye. MATERIALS AND METHODS: Bovine and human teeth were used. The dentin surface was exposed using water-irrigated #600 grit SiC paper and etched with varying dilutions of aquaeous solutions of phosphoric and maleic acid. Groups of 10 teeth per acid concentration were embedded in PMMA and Scotchbond Multi-Purpose (SMP) and cylinders of Z100 resin composite were bonded to their surfaces. These teeth were shear tested to failure and the failed surfaces subjected to SEM. Groups of three teeth per acid concentration had SMP and cylinders of Z100 bonded to their surfaces. These teeth were decalcified in concentrated HCL acid. The resultant cylinders and their attached resin tags were either subjected to SEM or stained with Alcian Blue dye. The latter specimens were embedded and prepared for light-microscopic examination. A further three human and three bovine teeth per acid concentration were etched and then prepared for SEM examination. All teeth for SEM were critical point dried. RESULTS: Resin tags were shown to consist of both resin and the glycosaminoglycans (GAG) sheath lining of the dentin tubule. As a result of the SEM observations, three mechanisms are suggested for the formation of resin tags, two of which will probably be found in vivo.

Acid Etching, Dental↗
PubMed1994

Penetration of a dentin bonding agent into dentin.

PURPOSE: To examine how the priming agents of Scotchbond Multi-Purpose (SMP) influenced the wettability of collagen in the demineralized zone and hence the penetration and adaptation of its bonding monomers. MATERIALS AND METHODS: Freshly extracted bovine teeth were ground to dentin with SiC paper. SMP and Z100 resin were used. Shear bond testing was performed as well as scanning electron microscopic evaluation. RESULTS: In contrast to the manufacturer's instructions, a 26.3% increase in shear bond strength was obtained when a second coat of priming agent was applied. This increase was statistically significant at the 5% level of confidence. SEM examination of failed conventionally air dried (CAD) specimens showed the presence of voids in the demineralized layer. SEM examination of failed specimens prepared by a critical point drying (CPD) technique showed that these voids were filled with collagen fibrils. The CPD technique also clearly showed that collagen fibrils were incorporated in the unfilled resin. Although priming agents appear to facilitate the penetration of unfilled resin into the demineralized layer and the dentin tubules, areas of unincorporated collagen fibrils can be seen even after two or more applications of the priming agent.

Analysis of Variance↗
PubMed1994

The morphology of the demineralized layer in primed dentin.

This study critically examined the surface and subsurface effects of selected dentin priming agents. Various dentin priming agents were used and specimens were prepared for SEM examination by conventional air drying or by a freeze fracture and critical point drying technique. The results showed that in specimens prepared by freeze fracture and critical point drying technique the demineralization of the dentin surface and subsurface by priming agents leaves a visible network of collagen fibrils. This technique allows better evaluation of the adaptation of bonding resins to the collagen network of the demineralized layer.

Acid Etching, Dental↗
PubMed1992

Advances in the treatment of acquired and developmental defects of hard dental tissues.

With the decline in dental caries, the dental profession and the general public have become sensitized to the "new" specialty of cosmetic dentistry. As a consequence, research in the field of dental materials for the ideal, most natural restorative materials and techniques has become a primary focus and has had a profound influence on dental education and practice. This brief article will highlight some of these newer concepts.

Composite Resins↗