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Gillam DG, Newman HN, Bulman JS, Davies EH. Dentifrice abrasivity and cervical dentinal hypersensitivity. Results 12 weeks following cessation of 8 weeks' supervised use. J Periodontol 1992; 63:7-12. [PMID: 1313104 DOI: 10.1902/jop.1992.63.1.7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Following an 8-week controlled investigation of 2 strontium chloride hexahydrate dentifrices (SCH) of differing abrasivity, 2 groups of 20 subjects each, with cervical dentinal hypersensitivity, were re-examined at 20 weeks; that is, 12 weeks after the active period. The examination procedures were conducted in the same manner as in the main clinical trial. Sensitivity levels were assessed by 2 instrument methods: tactile (Yeaple probe), and cold air (dental air syringe), and by subjective perception of pain by means of a Visual Analogue Scale. The results from these methods of assessment demonstrated that 12 weeks following the cessation of 8 weeks' controlled use of standard and low abrasive SCH dentifrices, sensitivity levels reversed on slightly in both groups and, overall, sensitivity remained significantly lower than at baseline. The abrasivity of the dentifrice did not affect the desensitivity activity.
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Abstract
Specific ion metering of fluoride ion levels of water samples obtained after passage through water softeners and a conditioner showed no alteration in concentration when compared with controls. Similar comparison of water samples passed through water filters demonstrated that highly significant amounts of fluoride ion were removed. In one filter tested, 90% of the fluoride content was lost in the filtration process. The findings of this study suggest that, in a household using a filter, it may be necessary to increase the fluoride supplement or in some cases to initiate use of fluoride supplements as children are not receiving as much fluoride as was thought. New guidelines are required to take account of this surprising effect.
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Van der Zee E, Davies EH, Newman HN. Marking width, calibration from tip and tine diameter of periodontal probes. J Clin Periodontol 1991; 18:516-20. [PMID: 1894745 DOI: 10.1111/j.1600-051x.1991.tb00083.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The present study comprises an investigation of 7 different probe types, representing currently-marketed major designs (WHO-CPITN, Williams, Michigan), as well as available calibration systems (engraved, etched and painted markings). Width of markings, accuracy of calibration from probe tip, and tine diameter at the tip and at specified points along the tine were assessed, using a stereomicroscope at a magnification of x 40. Blind duplicate measurements of these probe tine characteristics were 100% reproducible to within 0.01 mm. There was an overall range in marking width from 0.00-1.13 mm. The best marking, in that it had no appreciable width and the highest accuracy, was the discrete transition between normal and engraved parts of probes with engraved bands. Mean inaccuracies of different probe sets varied from 0.06 to 0.22 mm. Probes from the same batch from the same production line could differ by more than 0.5 mm in calibration. Mean tip diameter ranged from 0.28 to 0.70 mm. It was concluded that probe tine diameter and calibration should be considered in addition to other variables of periodontal probing. Standardisation of tine characteristics and avoidance of the use of different types or batches in a single study should enhance the accuracy and reproducibility of periodontal probe-dependent measurements.
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29
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Chiew SY, Wilson M, Davies EH, Kieser JB. Assessment of ultrasonic debridement of calculus-associated periodontally-involved root surfaces by the limulus amoebocyte lysate assay. An in vitro study. J Clin Periodontol 1991; 18:240-4. [PMID: 1856304 DOI: 10.1111/j.1600-051x.1991.tb00421.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
This investigation assessed the effectiveness of an in vitro ultrasonic debridement regime on periodontally involved teeth with visually-detectable calculus deposits, using the LAL assay for lipopolysaccharides (LPS) as a marker of bacterial products. 34 single rooted teeth with extensive amounts of calcified accretions were selected, of which 10 served as uninstrumented controls for the estimation of existing LPS levels. The periodontally involved roots of the 24 experimental teeth were debrided with a Cavitron TF-10 tip for a limited time using light pressure and overlapping strokes which ensured complete surface instrumentation without reference to the presence of calculus. Marked reductions in root surface area coverage by calculus were nevertheless achieved as assessed planimetrically from photographic records of the teeth before and after debridement. The root surfaces of each tooth were then stripped away and the harvested material subjected to 'Westphal' extraction and LAL assay for LPS. The resulting LPS yields from the experimental teeth ranged from less than 0.08 to 22.387 ng compared to 1,900 to 29,200 ng from the uninstrumented controls. The extremely small residual LPS yields from the experimental teeth not only confirm the efficacy of ultrasonic debridement but, when coupled with the lack of a relationship with the widely varying amounts of the remaining calculus, support the contention that bacterial plaque rather than calculus has the greater pathogenic potential. These results reinforce the growing impression of the superficial location of bacterial toxic products associated with periodontally involved root surfaces.
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Smart GJ, Wilson M, Davies EH, Kieser JB. The assessment of ultrasonic root surface debridement by determination of residual endotoxin levels. J Clin Periodontol 1990; 17:174-8. [PMID: 2180992 DOI: 10.1111/j.1600-051x.1990.tb01082.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Recent demonstrations of the superficial nature and ease of removal of root-surface-associated cytotoxic materials suggest that extensive root-surface instrumentation is not warranted clinically. This in vitro investigation determined the detoxifying effects of a conservative regime of ultrasonic root debridement, using the Limulus amoebocyte lysate assay for lipopolysaccharide (LPS) as an indication of the presence or absence of cytotoxic materials. 20 extracted periodontally-involved single-rooted teeth, with no clinically detectable calculus deposits, were debrided with a Cavitron TF-10 tip. Light pressure, resulting from a force application of approximately 50 g, lasting for 0.8 s/mm2 of root surface was used and complete overlapping instrumentation ensured. The finding of LPS levels of less than 2.5 ng per root in 19 out of 20 teeth after such debridement was comparable to LPS levels found on healthy, uninvolved control teeth, and thus endorses the growing belief that root surface cleanliness can be readily achieved.
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31
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Awang H, Hill FJ, Davies EH. An investigation of three polymeric materials for acid-etch splint construction. JOURNAL OF PAEDIATRIC DENTISTRY 1985; 1:55-60. [PMID: 3908634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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32
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Abstract
A mixture containing 18% polyvinylacetate exhibits the optimum physical properties for mouth protection in contact sports.
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Abstract
Two commercially available amalgam alloy powders (one lathe-cut, the other spherical) were characterized in terms of density, surface area, particle size distribution and appearance under the scanning electron microscope. A third, experimental alloy powder, prepared by electrodeposition, was subjected to a similar analysis. It was found that particle size distribution can be a misleading indicator, in that when particles are porous, inordinately large amounts of mercury will be taken up on trituration, and the resulting amalgam will have wholly unsatisfactory mechanical properties. Surface area measured by BET (gas adsorption) may be the best single index of the morphological quality of an amalgam alloy powder.
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34
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35
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36
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Fischel HF, Cruickshanks-Boyd DW, Davies EH. Setting characteristics and porosity of a composite resin. QUINTESSENCE INTERNATIONAL, DENTAL DIGEST 1982; 13:1345-51. [PMID: 6218512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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37
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Davies EH, Kuhn AT, Oleschenko SV. Tensile and shear strength measurements on brazed "T" joints used in construction of intra- and intermaxillary hooks. BRITISH JOURNAL OF ORTHODONTICS 1982; 9:185-9. [PMID: 6958322 DOI: 10.1179/bjo.9.4.185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Silver-brazed "T" joints, representing the first stage in the construction of intermaxillary hooks were fabricated under rigorously controlled conditions. Their tensile and shear strengths were then measured using specially developed test jigs. It was found that the braze joint itself was stronger than the component wires (under tensile load) while in shear mode, fracture occurred in one of a number of well-defined ways. The effect of prolonged heating was investigated using microhardness measurements and recommendations are made for the optimum brazing conditions.
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38
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Wilson GS, Davies EH, von Fraunhofer JA. Abrasive wear characteristics of anterior restorative materials. Br Dent J 1981; 151:335-8. [PMID: 6946798 DOI: 10.1038/sj.bdj.4804696] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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39
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Lingard GL, Davies EH, Von Fraunhofer JA. The interaction between lining materials and composite resin restorative materials. J Oral Rehabil 1981; 8:121-9. [PMID: 6453213 DOI: 10.1111/j.1365-2842.1981.tb00485.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The effects of four lining materials, Dycal, Procal, Cavitec and Poly F cement on Adaptic and Concise have been investigated in vitro. The parameters studied were surface roughness, hardness and colour both with and without an intermediate (or bonding) resin being present between the restorative material and the liner. The effects of the four liners on the composites varied both between the lining materials themselves and with the composite resin. Two materials, Procal and Dycal, had little interaction with the composites, provided an intermediate resin was used with the latter. Cavitec appeared to have an adverse reaction with the composites and Poly F, whilst having no effect on the colour of the composites, did increase surface roughness. The adverse effects of linig materials were ascribed to minor constituents, particularly methyl salicylate, present in the formulation.
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40
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Collie AD, Davies EH, Cruickshanks-Boyd DW. An in vitro investigation of composite resin splint designs. QUINTESSENCE INTERNATIONAL, DENTAL DIGEST 1980; 11:69-73. [PMID: 6933609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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41
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Wilson GS, Davies EH, von Fraunhofer JA. Micro-hardness characteristics of anterior restorative materials. Br Dent J 1980; 148:37-40. [PMID: 6927954 DOI: 10.1038/sj.bdj.4804370] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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42
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Keng SB, Cruickshanks-Boyd DW, Davies EH. Processing factors affecting the clarity of a rapid-curing clear acrylic resin. J Oral Rehabil 1979; 6:327-35. [PMID: 291704 DOI: 10.1111/j.1365-2842.1979.tb00413.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The difficulty in repeatedly producing unblemished, clear acrylic resin in the dental laboratory has hindered its wider use, despite its many advantages over coloured material. Recently, rapid-cure dental acrylics have been introduced, which are available in both clear and coloured forms. This investigation examined various factors which may influence the production of unblemished, rapid-curing, clear acrylic resin. Utilizing a quantitative assessment of clarity, the most important factor influencing the clarity of the resin is shown to be the choice of separating medium. Tin-foil produces extremely high clarity, but alginate mould separator causes surface blanching. However, this surface blanching can be removed by polishing. Porosity, caused by too rapid curing, and stone model dryness are of only secondary importance. Possible water contamination of the monomer liquid due to accidental exposure only affects clarity at very high levels of contamination.
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43
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Hunt JL, Cruickshanks-Boyd DW, Davies EH. The marginal characteristics of collarless bonded porcelain crowns produced using a separating medium technique. QUINTESSENCE OF DENTAL TECHNOLOGY 1978; 2:21-6. [PMID: 388535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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44
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Lingard GL, Davies EH, von Fraunhofer JA. An in vitro study of the staining of anterior restorative materials. J Dent 1978; 6:247-58. [PMID: 81219 DOI: 10.1016/0300-5712(78)90250-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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45
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Fulford HV, Cruickshanks-Boyd DW, Davies EH. The deterioration in cutting behaviour of reamers after use. JOURNAL OF THE BRITISH ENDODONTIC SOCIETY 1978; 11:53-60. [PMID: 294434 DOI: 10.1111/j.1365-2591.1978.tb00662.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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46
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Cruickshanks-Boyd DW, Davies EH. A simple method for determining the transparency of dental materials. J Med Eng Technol 1978; 2:28-9. [PMID: 621726 DOI: 10.3109/03091907809161746] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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47
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Bell JW, Davies EH, von Fraunhofer JA. The dimensional changes of elastomeric impression materials under various conditions of humidity. J Dent 1976; 4:73-82. [PMID: 1062409 DOI: 10.1016/0300-5712(76)90004-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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48
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Suchatlampong C, Davies EH, von Fraunhofer JA. Some physical properties of four resilient lining materials. J Dent 1976; 4:19-27. [PMID: 1063139 DOI: 10.1016/0300-5712(76)90066-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
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49
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Wittrock JW, Morrant GA, Davies EH. A study of temperature changes during removal of amalgam restorations. J Prosthet Dent 1975; 34:179-86. [PMID: 1097656 DOI: 10.1016/0022-3913(75)90011-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Because tooth preparation is only one of several potent causes of trauma to the pulp during clinical procedures, the objective should be to increase the chance of pulp survival by reducing this trauma wheneve- possible. In case of tooth preparation, this study shows that there is far less potential for pulpal damage when water is used as a coolant.
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50
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Dimashkieh MR, Davies EH, von Fraunhofer JA. Measurement of the cement film thickness beneath full crown restorations. Br Dent J 1974; 137:281-4. [PMID: 4613364 DOI: 10.1038/sj.bdj.4803306] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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