Papers by Richard Van Noort
Journal of Dentistry, Sep 1, 1985
This is the second part of the report on the 1982 literature on dental materials. Included are re... more This is the second part of the report on the 1982 literature on dental materials. Included are reviews on impression, cast, die and mould materials, polymeric prosthetic materials, aspects of adhesion. fissure sealants. composite resins, cements and endodontic materials. Biological properties Qvist and Stoltze (1982) have made a study of the long-term pulpal reactions of 60 experimental fillings. Results showed that variation in experimental conditions related to individual tooth and cavity preparation significantly influenced the degree of these reactions. Other work on biological properties has been reported elsewhere in this review under specific headings.
Dental Materials, Feb 1, 2008
The purpose of this study was to compare the interfacial fracture toughness of smooth and roughen... more The purpose of this study was to compare the interfacial fracture toughness of smooth and roughened ceramic surfaces bonded with a luting resin using an optimized method of silane treatment.
Journal of Prosthodontics, Aug 1, 2011
Turkyilmaz and Jones 12.Eliasson A, Blomqvist F, Wennerberg A, Johansson A. A retrospective analy... more Turkyilmaz and Jones 12.Eliasson A, Blomqvist F, Wennerberg A, Johansson A. A retrospective analysis of early and delayed loading of full-arch mandibular prostheses using three different implant systems: clinical results with up to 5 years of loading. Clin Implant Dent Relat Res 2009;11:134-48. 13.Simonis P, Dufour T, Tenenbaum H. Long-term implant survival and success: a 10-16 year follow-up of non-submerged dental implants Clin Oral Implants Res. 2010;21:772-7.
Dental Materials, Sep 1, 2004
Objectives. The purpose of this study was to investigate the process of hydrolysis and chemical s... more Objectives. The purpose of this study was to investigate the process of hydrolysis and chemical stability of a pre-activated silane solution stored for different periods of time. The tensile bond strength of resin composite to ceramic was also evaluated in order to determine the functional effectiveness after storage of the preactivated silane solutions. Methods. Silane solutions using g-methacryloxypropyltrimethoxysilane (g-MPTS), acetic acid and ethanol were freshly prepared and kept for 15 min, 2 h, 24 h, 1 week, 1 month, 6 months, and 1 year. The solutions were analyzed using a 2000 Perkin-Elmer Fourier transform infrared (FT-IR) spectrophotometer. For the tensile bond strength test, Ni/Cr rods were prepared with ceramic facings polished to 1 mm. Five groups of ceramic surfaces ðn ¼ 60Þ were treated with the pre-activated silane solutions and bonded using a luting resin. The process used to prepare the surfaces prior to bonding consisted of removing unreacted silane by boiling water and then heat treatment. Each group was then subdivided into two groups ðn ¼ 30Þ and stored under two different storage conditions before subjecting to the tensile bond strength test; either (1) dry at room temperature for 24 h or (2) boiling water for 24 h. Results. FT-IR analysis showed that nearly complete hydrolysis of g-MPTS has occurred 24 h after mixing, followed more slowly by the formation of siloxane (Si-O-Si) oligomers. The bond strength test results showed that there was no statistically significant difference in the mean tensile bond strength for any of the groups either in dry condition or in boiling water ðP. 0:05Þ: The mode of failure for all groups was predominantly cohesive failure within the resin. The silane bond was also capable of resisting hydrolytic attack in boiling water for all the groups. Significance. From the results of this study it can be concluded that, when using an appropriate silane application technique, the adhesive effectiveness of a preactivated silane solution based on g-MPTS, acetic acid and ethanol will not deteriorate when stored for up to 1 year at room temperature.
Engineering in Medicine, Oct 1, 1978
ABSTRACT
Journal of Dentistry, Feb 1, 1994
Journal of Dentistry, Mar 1, 1998
This critical review of the published literature on dental materials for the year 1996 has been c... more This critical review of the published literature on dental materials for the year 1996 has been compiled by the Dental Materials Panel of the UK. It continues the series of annual reviews started in 1973 and published in the Journal of Dentistry. Emphasis has been placed upon publications which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, resin-bonded bridges and ceramo-metallic restorations, ceramics, denture base resins and soft lining materials, impression materials, implants materials, orthodontic materials, biomechanics and image processing, resin composites and casting investment materials and waxes). Three hundred and thirteen articles have been reviewed.
Journal of Materials Science, 1979
Passive prosthetic devices, for example artificial heart valves, can be manufactured from elastom... more Passive prosthetic devices, for example artificial heart valves, can be manufactured from elastomeric materials such as silicone rubber. This paper describes how optimum properties for a medical grade heat-vulcanizing silicone rubber can be best achieved. The paper will also describe how the properties of these materials are affected by the different cleaning and sterilization procedures which may be used. The in viva response of this silicone rubber to subcutaneous implantation in guinea pigs has been investigated for periods of up to ten months. Scanning electron microscopy of the surfaces of these elastomers has been performed. As a result, it has been possible to perform detailed examinations of the topological features of the surfaces prior to and after implantation.
The Annals of Thoracic Surgery, May 1, 1982
The uniaxial stress/strain response of bovine pericardium up to a stress of 1 N/mm2 was studied. ... more The uniaxial stress/strain response of bovine pericardium up to a stress of 1 N/mm2 was studied. The tissue was chemically modified in 0.5% buffered glutaraldehyde for 24 hours under various conditions of constraint. Four groups were studied: an unrestricted control group, a group held at their original length, a group stretched to a stress of 0.04 N/mm2, and a group stretched to a stress of 0.4 N/mm2 during treatment. Histological examination revealed changes in structural organization of the collagen, which explained the alterations in the stress/strain response. A significant alteration in mechanical properties after glutaraldehyde treatment was observed, with considerable loss of extensibility for the prestretched tissues. A valve made from such a prestretched tissue may be stenotic and possibly subject to early failure.
Journal of Materials Science: Materials in Medicine, Feb 1, 1994
In this study the effect of size and distribution of leucite crystals on the biaxial flexural str... more In this study the effect of size and distribution of leucite crystals on the biaxial flexural strength of five leucite reinforced glass-ceramics used in dentistry for the construction of veneers was investigated. Three of these were found to have a non-uniform distribution of leucite crystals, which were associated with a considerable degree of microcracking in the glassy matrix around the
Journal of Dentistry, 2010
This study was a preliminary evaluation of two minimal preparation designs proposed for ceramic a... more This study was a preliminary evaluation of two minimal preparation designs proposed for ceramic and composite resin bonded CAD/CAM crowns. It compared the structural integrity and fracture mode of teeth restored with traditionally and minimally prepared resin bonded CAD/CAM crowns fabricated from the same material hypothesizing that teeth restored with minimal resin bonded crowns would demonstrate the same fracture strength to teeth restored with traditional resin bonded crowns. Forty intact maxillary molar teeth were used and divided in four groups. Two groups were prepared according to a traditional crown preparation design and two groups were prepared according to minimal preparation designs. A resin composite (Paradigm MZ100, 3M ESPE) and a leucite glass-ceramic (ProCAD, Ivoclar Vivadent) were used for the fabrication of the crowns using CEREC Scan. Crowns of ceramic were cemented using Variolink II (Ivoclar Vivadent) and crowns of composite with Rely X Unicem Aplicap (3M ESPE) and loaded until fracture. Load data was analysed using ANOVA comparing crowns of the same restorative material. The mode of fracture was also recorded and analysed (Kruskal-Wallis). For the composite system the mean fracture load and SD was 1682N (+/-315) for the traditional and 1751N (+/-338) for the minimal crowns. For the ceramic system the mean fracture load and SD was 1512N (+/-373) for the traditional and 1837 (+/-356) for the minimal crowns. No statistically significant difference was found between the two designs for each system. Nonparametric analysis (Kruskal-Wallis) of the fracture mode showed no statistical significant difference between designs for either material (p>.05). Within the limitations of this experimental design, it was found that minimally prepared resin bonded CEREC crowns demonstrated equal fracture resistance and mode of fracture to that of crowns bonded to traditionally prepared teeth.
Journal of Dentistry, Dec 1, 2010
Objectives: To investigate and compare the marginal integrity of ceramic copings constructed with... more Objectives: To investigate and compare the marginal integrity of ceramic copings constructed with the CEREC3 and the EVEREST system employing three different margin angle designs and explore to what extent these CAD/CAM machines can produce acute marginal angles creating restorations with acceptable margins. Materials and methods: Three brass models were prepared with a different marginal finish line, namely a 08 bevel (or 908 shoulder), a 308 bevel and a 608 bevel. Ten restorations were produced for each finishing line and CAD/CAM system, respectively. The copings were milled from lithium disilicate glass ceramic blocks (IPS e.max 1 CAD). An impression was taken for each model to fabricate a series of 10 replica dies for each marginal design. Quantitative analysis of the margins of each coping was performed using digital photography and image analysis software. The marginal integrity of the restorations was evaluated by detecting and measuring any signs of marginal chipping and the Chipping Factor (CF) was calculated. Statistical analysis was performed using Univariate Analysis of Variance and multiple comparisons (Tukey HSD). Results: The average Chipping Factor (CF) of the CEREC copings was: 2.8% for the 08 bevel angle, 3.5% for the 308 bevel angle and 10% for the 608 bevel angle. For the EVEREST copings the average CF was: 0.6% for the 08 bevel angle, 3.2% for the 308 bevel angle and 2.0% for the 608 bevel angle. Univariate Analysis of Variance and multiple comparisons showed that there was a statistically significant difference in the quality of margins between the two systems for the 08 and 608 bevel finishing line. Conclusions: The results of this study indicated that the introduction of a marginal angle of the restoration increases the potential for marginal chipping. Different CAD/CAM systems which employ different milling processes produce restorations with different amount of marginal chipping, although this only became apparent for a marginal angle of a 608.
Journal of Dentistry, Aug 1, 1999
This review of the published literature on dental materials for the year 1997 has been compiled b... more This review of the published literature on dental materials for the year 1997 has been compiled by the Dental Materials Panel of UK. It continues a series of annual reviews started in 1973. Emphasis has been placed upon publications, which report upon the materials science or clinical performance of the materials. The review has been divided by accepted materials classifications (fissure sealants, glass polyalkenoate cements, dentine bonding, dental amalgam, endodontic materials, casting alloys, ceramometallic restorations and resin-bonded bridges, ceramics, denture base resins and soft lining materials, impression materials, dental implant materials, orthodontic materials, biomechanics and image processing, resin composites, and casting investment materials and waxes). Three hundred and thirty three articles have been reviewed.
Dental Materials, May 1, 2009
d e n t a l m a t e r i a l s 2 5 (2 0 0 9) e5-e46 e45 evaluation criteria as described by Hickel... more d e n t a l m a t e r i a l s 2 5 (2 0 0 9) e5-e46 e45 evaluation criteria as described by Hickel et al. [J Adhes Dent 2007;9:121-47] (table). The statistical analysis was performed using SPSS 16.00. Aesthetic properties A1 clinically excellent/very good A2 clinically good A3 clinically sufficient/satisfactory A4 clinically unsatisfactory A5 clinically poor Translucency 3.1 no difference in shade and translucency 3.2 minor deviations 3.3 clear deviations but acceptable 3.4 (localized) clinically unsatisfactory 3.5 unacceptable Results: In 39 (73.6%) cases [23 inlays (59%), 16 partial crowns (41%)], the aesthetic properties of the restoration was rated as clinically excellent/very good (A1). 14 (26.4%) restorations [2 inlays (14%) and 12 partial crowns (86%)], were rated as clinically good (A2) for their aesthetic properties. None of the ceramic restorations were evaluated as A3, A4 or A5. Nearly all restorations (37 cases = 94.9%) rated as clinically excellent/very good (A1) showed no difference in shade and translucency (rate 3.1). Just two restorations (5.1%) appeared clinically with minor deviations in translucency (rate 3.2). The group of restorations rated as clinically good (A2) contained 10 (71.4%) restorations with no difference in shade and translucency (rate 3.1) and 4 (28.6%) restorations with minor deviations in translucency (rate 3.2). None of the ceramic restorations appeared with a translucency rate 3.3, 3.4 or 3.5. Conclusions: The e.max press ceramic with the new hightranslucency has the potential to create inlays and partial crowns of defect-oriented tooth preparations with high aesthetic properties and a naturally appearing translucency.
Dental Materials, Dec 1, 2008
Key Engineering Materials, Dec 1, 2001
The journal of adhesive dentistry, 2007
PURPOSE To correlate the microtensile bond strength (microTBS) of dentin bonding agents to dentin... more PURPOSE To correlate the microtensile bond strength (microTBS) of dentin bonding agents to dentin for different hourglass designs with the stress distribution across the adhesive interface utilizing finite element stress analysis (FEA). MATERIALS AND METHODS Adper Scotchbond Multipurpose Plus dentin bonding agent was bonded to flat dentin surfaces in three experimental groups. A 5- to 6-mm layer of resin composite (Filtek Supreme, 3M ESPE) was built up incrementally. After 24 h water storage at 37 degrees C, the bonded teeth were sectioned into hourglass designs of circular, parabolic, and spline shape, with a ca 1 mm2 cross-sectional area at the bonded interface (n=30). The specimens were subjected to microTBS testing at a crosshead speed of 0.5 mm/min. The fracture surfaces were examined under SEM to determine the modes of failure. FEA models were constructed using the TOMECH program. A load of 100 N was applied and the stresses at the bonded interfaces were viewed using the FEMSY...
Engineering in Medicine, Oct 1, 1978
A new method for the measurement of abdominal wound strength in laboratory animals (rats) is desc... more A new method for the measurement of abdominal wound strength in laboratory animals (rats) is described in detail. Preliminary experiments have been carried out and the results reported. These show the suitability of a diaphragm testing technique for measurement of wound strength in that it provides a more meaningful profile of the repair processes in abdominal wounds and makes possible the quantitative measurement of wound healing.
Dental Materials, 2001
Objective: The bond of a silane-coupling agent to a ceramic surface is expected to be in¯uenced b... more Objective: The bond of a silane-coupling agent to a ceramic surface is expected to be in¯uenced by the composition and chemical state of the ceramic surface. The purpose of this study was to determine the variation in the composition and the chemical states of the surfaces of a range of leucite-reinforced feldspathic (LRF) ceramics using X-ray photoelectron spectroscopy (XPS). Methods: Five LRF ceramic discs (IPS Empress,Optec HSP,VMK 68, Mirage, and a modi®ed Mirage) were produced and polished to a 1 mm ®nish. A further nine discs of the modi®ed Mirage were produced. The discs were stored for 48 h in a vacuum oven at 1108C to remove absorbed water. The surfaces of these discs were analysed by XPS. Survey scans at 308 takeoff angle were taken and surface composition (in at%) was calculated from the narrow scans for Si 2p, O 1s, Al 2p, Mg 2s, K 2p, Na 1s, Ca 2p and N 1s. Results: Atomic concentration of elements (after exclusion of C) for the ®ve LRF ceramics were in the range: O, 45.0±51.6%; Si, 26.7± 35.6%; Al, 6.3±9.7%; Mg, 4.9±8.8%; K, 0.5±2.2%; N, 0.9±2.9% and less than 1% of Na and Ca. The shapes of the O 1s and Si 2p narrow scan core lines of the ®ve LRF ceramics were virtually identical. Signi®cance: All ®ve LRF ceramics were found to have a silica-rich surface layer due to a reduction in K and Na relative to the bulk composition. Both the composition and chemical states of the surfaces for the ®ve LRF ceramics were very similar.
Journal of Pediatric Surgery, Feb 1, 1982
The mechanical strength of incisions in the anterior abdominal wall using either scalpel or elect... more The mechanical strength of incisions in the anterior abdominal wall using either scalpel or electrocautery was compared by measuring the bursting stresses of the resulting wounds. Statistically significant differences were shown to occur in the first and thirty-fifth postoperative days. Between the seventh and tenth postoperative days, when wound dehiscence is most likely to occur, no difference in the rupture strength could be detected.
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Papers by Richard Van Noort