This study investigated whether teaching undergraduate dental students the diagnosis and manageme... more This study investigated whether teaching undergraduate dental students the diagnosis and management of acute dental pain alongside the underpinning oral physiology helped them to understand the topic better than teaching them acute dental pain as a separate entity. Each of three clinical years of dental students at the same dental school was taught in two groups. Each group was taught the signs/symptoms of five acute dental pain conditions by the same member of the staff. However, the teaching for one group of students in each year reminded the students about the physiology that underpinned the clinical symptoms. One week later, the students completed an open‐ended questionnaire that required them to list signs/symptoms of the five dental pain conditions. For each year of dental students that was examined, the mean student marks were significantly higher (p<0.05) for those who were taught dental pain and the underlying physiology compared with students who were only taught dental...
ABSTRACT Standard specifications for the sizes of specimens used in testing the strength of Glass... more ABSTRACT Standard specifications for the sizes of specimens used in testing the strength of Glass-Ionomer cements are relatively large. Probably on account of problems associated with the preparation of such specimens, researchers on many occasions have used smaller specimen sizes in their tests. The aim of this study was to determine the effect of specimen size on the 24 h compressive and tensile strengths of a Glass-Ionomer cement. Using Vitrabond light curing Glass-Ionomer liner/base material, specimens of standard sizes, together with specimens of considerably smaller sizes, were prepared, and comparisons of compressive and diametral tensile strength values were made. No significant differences were found in the values obtained for the differently-sized specimens.
Primary dental care : journal of the Faculty of General Dental Practitioners (UK), 2008
To investigate the effect of water temperature, in association with four denture cleansers, on th... more To investigate the effect of water temperature, in association with four denture cleansers, on the colour and surface roughness of five soft lining materials. Two silicone soft lining materials (Molloplast B and Sofreliner) represented the heat-cured, laboratory-based and chairside materials that are available. The wide range of chairside, acrylic resin-based, temporary soft lining materials was represented by Coe-Soft, Viscogel and Eversoft. An alkaline hypochlorite (Dentural) and three effervescent peroxide solutions with a range of active pH values (Steradent Active Plus, pH 6; Steradent Extra Strength, pH 3; Superdrug Fresh, pH 11) were selected as the cleansers. The denture cleansers were used at two temperatures: 55 degrees C (manufacturers' recommended temperature) and 80 degrees C. The colour of the specimens was evaluated using a colorimeter and the surface roughness was assessed using a three-dimensional, non-contact surface profilometer. This study reported on the eff...
ABSTRACT Poly (methyl methacrylate), the material most commonly used in the construction of dentu... more ABSTRACT Poly (methyl methacrylate), the material most commonly used in the construction of dentures, is not without limitations particularly in terms of mechanical strength, such as flexural and fatigue strength. The Dental Practice Board for England statistics show that many dentures fail as a result of fracture. This study investigated the self-reinforcement of acrylic resin through the addition of surface treated poly (methyl methacrylate) fibres in chopped and continuous form. The effect of the addition of fibres on transverse and impact strengths was investigated. The addition of surface treated chopped or continuous fibres to acrylic resin did not improve the transverse or impact strengths. The addition of surface treated poly (methyl methacrylate), in the present form, to acrylic resin cannot be recommended as a method of reinforcement.
A prototype teledentistry service was established that incorporated a PC-based expert system desi... more A prototype teledentistry service was established that incorporated a PC-based expert system designed to assist in orthodontic cases. It guided the general dental practitioner (GDP) through the assessment of a patient&#39;s malocclusion and helped ensure that all relevant clinical observations were made and details recorded. The resulting data file, containing radiographic images and clinical data, was then transferred via the Internet to a dental specialist. The specialist&#39;s recommendations were returned by the same route or, where appropriate, a realtime videoconference was conducted. During an eight-month trial, six GDPs referred 158 cases through the teledentistry system; another 24 cases were referred directly to a local consultant. The protocol used during the trial worked satisfactorily. The GDPs found that it was straightforward and covered all aspects of the cases they submitted.
Objectives: Formulations of commercially available denture cleaners vary widely. Unfortunately, c... more Objectives: Formulations of commercially available denture cleaners vary widely. Unfortunately, comparative data to suggest which products are the most effective can become invalid as newer products are introduced or formulations are changed. The aim of this in vitro study was to measure the stain removal properties of four currently available denture cleaners. Methods: Stain was deposited on multi-well polystyrene saliva coated microplates using multiple chlorhexidine and tea solutions. Following drying, each stained well was exposed to a solution of denture cleaner, dried again and the amount of stain remaining measured using a microplate reader. The cleaning procedure was repeated with further multiple exposures of the wells to solutions of the denture cleaners. Results: All denture cleaners removed stain better than water used as a control. At five cleaning cycles only one of the cleaners (Superdrug Cleaning Powder) had removed 100% of the stain. At 30 cycles three of the cleaners had removed 100% of the stain. Conclusions: All the commercial denture cleaners removed stain. Superdrug Cleaning Powder, which contains sodium percarbonate and sodium lauryl sulphate, was particularly effective.
This article describes a pilot trial to determine whether the transmission of digitized clinical ... more This article describes a pilot trial to determine whether the transmission of digitized clinical records of potential orthodontic cases supported by access to video and data conferencing may help to reduce the current high level of inappropriate referrals to consultant orthodontists in the UK.
The purpose of the present study was to investigate the effect of roughening the denture base sur... more The purpose of the present study was to investigate the effect of roughening the denture base surface on the tensile and shear bond strengths of a poly(dimethylsiloxane) resilient lining material (Molloplast-B) bonded to a heat-cured acrylic resin denture base material. These measured bond strengths were compared to those obtained by packing the soft lining material against poly(methyl methacrylate) (PMMA) denture base acrylic resin dough. Three groups of 10 specimens each were constructed for both tensile and shear tests. In the first group, Molloplast-B was packed against cured PMMA denture base surface. In the second group, Molloplast-B was packed against cured PMMA denture base whose surface had been roughened with an acrylic bur. In a third group, Molloplast-B was packed against PMMA denture base acrylic resin dough. Molloplast-B exhibited significantly higher tensile and shear bond strengths when packed against acrylic resin dough. Roughening the denture base surface prior to ...
The European journal of prosthodontics and restorative dentistry, 1997
UHMWPE in the form of experimental surface treated beads was added to acrylic resin denture base ... more UHMWPE in the form of experimental surface treated beads was added to acrylic resin denture base material in various percentages to form a composite material. The influence on doughing and manipulation times, and transverse and impact strength was examined. The results indicated that the manipulation times, were not significantly affected as the percentage of UHMWPE beads in the acrylic resin powder increased. Increasing the percentage of incorporated UHMWPE beads resulted in an inconsistent decrease in the modulus of rupture and no effect on the impact fracture resistance. It was concluded that the use of treated UHMWPE beads is of no significant benefit to the properties of acrylic resin.
This article describes a pilot trial to determine whether the transmission of digitized clinical ... more This article describes a pilot trial to determine whether the transmission of digitized clinical records of potential orthodontic cases supported by access to video and data conferencing may help to reduce the current high level of inappropriate referrals to consultant orthodontists in the UK.
To investigate the effect of water temperature, in association with four denture cleansers, on th... more To investigate the effect of water temperature, in association with four denture cleansers, on the colour and surface roughness of five soft lining materials. Two silicone soft lining materials (Molloplast B and Sofreliner) represented the heat-cured, laboratory-based and chairside materials that are available. The wide range of chairside, acrylic resin-based, temporary soft lining materials was represented by Coe-Soft, Viscogel and Eversoft. An alkaline hypochlorite (Dentural) and three effervescent peroxide solutions with a range of active pH values (Steradent Active Plus, pH 6; Steradent Extra Strength, pH 3; Superdrug Fresh, pH 11) were selected as the cleansers. The denture cleansers were used at two temperatures: 55 degrees C (manufacturers&amp;amp;#39; recommended temperature) and 80 degrees C. The colour of the specimens was evaluated using a colorimeter and the surface roughness was assessed using a three-dimensional, non-contact surface profilometer. This study reported on the effect of using both the higher temperatures and the recommended temperature on the colour and roughness of permanent and temporary soft lining materials. The results of the study showed that the temperature of the water used with denture cleansers might have a detrimental effect on the colour and surface roughness of some permanent and temporary soft lining materials.
Thermoformed poly(methyl methacrylate) (PMMA) sheet is used to produce a number of different dent... more Thermoformed poly(methyl methacrylate) (PMMA) sheet is used to produce a number of different dental appliances such as stents, occlusal splints and baseplates for occlusal rims. The purpose of the present study was to measure the accuracy of adaptation of Perspex PMMA sheet and to determine the effect of annealing on the accuracy of the thermoformed specimens. The results of the study showed that PMMA can produce specimens that are accurately adapted to the cast. Immersion in water resulted in an increase in the space between the cast and the specimen for both thermoformed and thermoformed and annealed acrylic resin. Annealing of the thermoformed specimens had significantly less increase in space between the cast and the specimens when immersed in water over a period of 3 months.
Poly (methyl methacrylate), the material most commonly used in the construction of dentures, is n... more Poly (methyl methacrylate), the material most commonly used in the construction of dentures, is not without limitations particularly in terms of mechanical strength, such as flexural and fatigue strength. The Dental Practice Board for England statistics show that many dentures fail as a result of fracture. This study investigated the self-reinforcement of acrylic resin through the addition of surface treated poly (methyl methacrylate) fibres in chopped and continuous form. The effect of the addition of fibres on transverse and impact strengths was investigated. The addition of surface treated chopped or continuous fibres to acrylic resin did not improve the transverse or impact strengths. The addition of surface treated poly (methyl methacrylate), in the present form, to acrylic resin cannot be recommended as a method of reinforcement.
The effect of aging four commercially-available dental composites in water or ethanol at 37TC for... more The effect of aging four commercially-available dental composites in water or ethanol at 37TC for periods of up to 28 days was assessed by measuring changes in the materials' plane-strain fracture toughness (KIC). The results, obtained by means of a mini Short Rod Fracture Toughness Test specimen design, suggest that while water aging does not produce significant changes in KIC, aging in ethanol does cause significant increases in fracture toughness for three of the four dental composites studied. In view ofpreviously-reported loss of wear resistance for dental composites aged in ethanol solutions, the present study emphasizes the difficulties in usingfracture toughness to predict wear properties. J Dent Res 66 : 722-726, March, 1987
... testing, however, should take into account the possibility of in vivo material degradation an... more ... testing, however, should take into account the possibility of in vivo material degradation and should recognize that ana-tomical constraints ... These standard tests include compact tension4-6, single-edge notch three-point bend (SEN)'-'' double-torsion (DT)"*'2, tapered cleavage ...
The clinical performance of light polymerised dental composites is greatly in#uenced by the quali... more The clinical performance of light polymerised dental composites is greatly in#uenced by the quality of the light-curing unit (LCU) used. Commonly used halogen LCUs have some speci"c drawbacks such as decreasing of the light output with time. This may result in low degree of monomer conversion of the composites with negative clinical implications. Previous studies have shown that blue-light-emitting diode (LED) LCUs have the potential to polymerise dental composites without having the drawbacks of halogen LCUs. Despite the relatively low irradiance of current LED LCUs, their e$ciency is close to that of conventional halogen LCUs with more than twice the irradiance. This phenomenon has not been explained fully yet. Hence, more tests of the LED LCU's e!ectiveness and of the mechanical properties of oral biomaterials processed with LED LCUs need to be carried out. This study investigates the #exural properties of three di!erent composites with three di!erent shades, which were polymerised with either a commercial halogen LCU or an LED LCU, respectively. In most cases no signi"cant di!erences in #exural strength and modulus between composites polymerised with a halogen LCU or an LED LCU, respectively, were found. A simple model for the curing e!ectiveness based on the convolution absorption spectrum of the camphorquinone photoinitiator present in composites and the emission spectra of the LCUs is presented.
Saliba E, Abbassi-Ghadi S, Vowles R, Camilleri J, Hooper S, Camilleri J. Evaluation of the streng... more Saliba E, Abbassi-Ghadi S, Vowles R, Camilleri J, Hooper S, Camilleri J. Evaluation of the strength and radiopacity of Portland cement with varying additions of bismuth oxide.
This study investigated whether teaching undergraduate dental students the diagnosis and manageme... more This study investigated whether teaching undergraduate dental students the diagnosis and management of acute dental pain alongside the underpinning oral physiology helped them to understand the topic better than teaching them acute dental pain as a separate entity. Each of three clinical years of dental students at the same dental school was taught in two groups. Each group was taught the signs/symptoms of five acute dental pain conditions by the same member of the staff. However, the teaching for one group of students in each year reminded the students about the physiology that underpinned the clinical symptoms. One week later, the students completed an open‐ended questionnaire that required them to list signs/symptoms of the five dental pain conditions. For each year of dental students that was examined, the mean student marks were significantly higher (p<0.05) for those who were taught dental pain and the underlying physiology compared with students who were only taught dental...
ABSTRACT Standard specifications for the sizes of specimens used in testing the strength of Glass... more ABSTRACT Standard specifications for the sizes of specimens used in testing the strength of Glass-Ionomer cements are relatively large. Probably on account of problems associated with the preparation of such specimens, researchers on many occasions have used smaller specimen sizes in their tests. The aim of this study was to determine the effect of specimen size on the 24 h compressive and tensile strengths of a Glass-Ionomer cement. Using Vitrabond light curing Glass-Ionomer liner/base material, specimens of standard sizes, together with specimens of considerably smaller sizes, were prepared, and comparisons of compressive and diametral tensile strength values were made. No significant differences were found in the values obtained for the differently-sized specimens.
Primary dental care : journal of the Faculty of General Dental Practitioners (UK), 2008
To investigate the effect of water temperature, in association with four denture cleansers, on th... more To investigate the effect of water temperature, in association with four denture cleansers, on the colour and surface roughness of five soft lining materials. Two silicone soft lining materials (Molloplast B and Sofreliner) represented the heat-cured, laboratory-based and chairside materials that are available. The wide range of chairside, acrylic resin-based, temporary soft lining materials was represented by Coe-Soft, Viscogel and Eversoft. An alkaline hypochlorite (Dentural) and three effervescent peroxide solutions with a range of active pH values (Steradent Active Plus, pH 6; Steradent Extra Strength, pH 3; Superdrug Fresh, pH 11) were selected as the cleansers. The denture cleansers were used at two temperatures: 55 degrees C (manufacturers' recommended temperature) and 80 degrees C. The colour of the specimens was evaluated using a colorimeter and the surface roughness was assessed using a three-dimensional, non-contact surface profilometer. This study reported on the eff...
ABSTRACT Poly (methyl methacrylate), the material most commonly used in the construction of dentu... more ABSTRACT Poly (methyl methacrylate), the material most commonly used in the construction of dentures, is not without limitations particularly in terms of mechanical strength, such as flexural and fatigue strength. The Dental Practice Board for England statistics show that many dentures fail as a result of fracture. This study investigated the self-reinforcement of acrylic resin through the addition of surface treated poly (methyl methacrylate) fibres in chopped and continuous form. The effect of the addition of fibres on transverse and impact strengths was investigated. The addition of surface treated chopped or continuous fibres to acrylic resin did not improve the transverse or impact strengths. The addition of surface treated poly (methyl methacrylate), in the present form, to acrylic resin cannot be recommended as a method of reinforcement.
A prototype teledentistry service was established that incorporated a PC-based expert system desi... more A prototype teledentistry service was established that incorporated a PC-based expert system designed to assist in orthodontic cases. It guided the general dental practitioner (GDP) through the assessment of a patient&#39;s malocclusion and helped ensure that all relevant clinical observations were made and details recorded. The resulting data file, containing radiographic images and clinical data, was then transferred via the Internet to a dental specialist. The specialist&#39;s recommendations were returned by the same route or, where appropriate, a realtime videoconference was conducted. During an eight-month trial, six GDPs referred 158 cases through the teledentistry system; another 24 cases were referred directly to a local consultant. The protocol used during the trial worked satisfactorily. The GDPs found that it was straightforward and covered all aspects of the cases they submitted.
Objectives: Formulations of commercially available denture cleaners vary widely. Unfortunately, c... more Objectives: Formulations of commercially available denture cleaners vary widely. Unfortunately, comparative data to suggest which products are the most effective can become invalid as newer products are introduced or formulations are changed. The aim of this in vitro study was to measure the stain removal properties of four currently available denture cleaners. Methods: Stain was deposited on multi-well polystyrene saliva coated microplates using multiple chlorhexidine and tea solutions. Following drying, each stained well was exposed to a solution of denture cleaner, dried again and the amount of stain remaining measured using a microplate reader. The cleaning procedure was repeated with further multiple exposures of the wells to solutions of the denture cleaners. Results: All denture cleaners removed stain better than water used as a control. At five cleaning cycles only one of the cleaners (Superdrug Cleaning Powder) had removed 100% of the stain. At 30 cycles three of the cleaners had removed 100% of the stain. Conclusions: All the commercial denture cleaners removed stain. Superdrug Cleaning Powder, which contains sodium percarbonate and sodium lauryl sulphate, was particularly effective.
This article describes a pilot trial to determine whether the transmission of digitized clinical ... more This article describes a pilot trial to determine whether the transmission of digitized clinical records of potential orthodontic cases supported by access to video and data conferencing may help to reduce the current high level of inappropriate referrals to consultant orthodontists in the UK.
The purpose of the present study was to investigate the effect of roughening the denture base sur... more The purpose of the present study was to investigate the effect of roughening the denture base surface on the tensile and shear bond strengths of a poly(dimethylsiloxane) resilient lining material (Molloplast-B) bonded to a heat-cured acrylic resin denture base material. These measured bond strengths were compared to those obtained by packing the soft lining material against poly(methyl methacrylate) (PMMA) denture base acrylic resin dough. Three groups of 10 specimens each were constructed for both tensile and shear tests. In the first group, Molloplast-B was packed against cured PMMA denture base surface. In the second group, Molloplast-B was packed against cured PMMA denture base whose surface had been roughened with an acrylic bur. In a third group, Molloplast-B was packed against PMMA denture base acrylic resin dough. Molloplast-B exhibited significantly higher tensile and shear bond strengths when packed against acrylic resin dough. Roughening the denture base surface prior to ...
The European journal of prosthodontics and restorative dentistry, 1997
UHMWPE in the form of experimental surface treated beads was added to acrylic resin denture base ... more UHMWPE in the form of experimental surface treated beads was added to acrylic resin denture base material in various percentages to form a composite material. The influence on doughing and manipulation times, and transverse and impact strength was examined. The results indicated that the manipulation times, were not significantly affected as the percentage of UHMWPE beads in the acrylic resin powder increased. Increasing the percentage of incorporated UHMWPE beads resulted in an inconsistent decrease in the modulus of rupture and no effect on the impact fracture resistance. It was concluded that the use of treated UHMWPE beads is of no significant benefit to the properties of acrylic resin.
This article describes a pilot trial to determine whether the transmission of digitized clinical ... more This article describes a pilot trial to determine whether the transmission of digitized clinical records of potential orthodontic cases supported by access to video and data conferencing may help to reduce the current high level of inappropriate referrals to consultant orthodontists in the UK.
To investigate the effect of water temperature, in association with four denture cleansers, on th... more To investigate the effect of water temperature, in association with four denture cleansers, on the colour and surface roughness of five soft lining materials. Two silicone soft lining materials (Molloplast B and Sofreliner) represented the heat-cured, laboratory-based and chairside materials that are available. The wide range of chairside, acrylic resin-based, temporary soft lining materials was represented by Coe-Soft, Viscogel and Eversoft. An alkaline hypochlorite (Dentural) and three effervescent peroxide solutions with a range of active pH values (Steradent Active Plus, pH 6; Steradent Extra Strength, pH 3; Superdrug Fresh, pH 11) were selected as the cleansers. The denture cleansers were used at two temperatures: 55 degrees C (manufacturers&amp;amp;#39; recommended temperature) and 80 degrees C. The colour of the specimens was evaluated using a colorimeter and the surface roughness was assessed using a three-dimensional, non-contact surface profilometer. This study reported on the effect of using both the higher temperatures and the recommended temperature on the colour and roughness of permanent and temporary soft lining materials. The results of the study showed that the temperature of the water used with denture cleansers might have a detrimental effect on the colour and surface roughness of some permanent and temporary soft lining materials.
Thermoformed poly(methyl methacrylate) (PMMA) sheet is used to produce a number of different dent... more Thermoformed poly(methyl methacrylate) (PMMA) sheet is used to produce a number of different dental appliances such as stents, occlusal splints and baseplates for occlusal rims. The purpose of the present study was to measure the accuracy of adaptation of Perspex PMMA sheet and to determine the effect of annealing on the accuracy of the thermoformed specimens. The results of the study showed that PMMA can produce specimens that are accurately adapted to the cast. Immersion in water resulted in an increase in the space between the cast and the specimen for both thermoformed and thermoformed and annealed acrylic resin. Annealing of the thermoformed specimens had significantly less increase in space between the cast and the specimens when immersed in water over a period of 3 months.
Poly (methyl methacrylate), the material most commonly used in the construction of dentures, is n... more Poly (methyl methacrylate), the material most commonly used in the construction of dentures, is not without limitations particularly in terms of mechanical strength, such as flexural and fatigue strength. The Dental Practice Board for England statistics show that many dentures fail as a result of fracture. This study investigated the self-reinforcement of acrylic resin through the addition of surface treated poly (methyl methacrylate) fibres in chopped and continuous form. The effect of the addition of fibres on transverse and impact strengths was investigated. The addition of surface treated chopped or continuous fibres to acrylic resin did not improve the transverse or impact strengths. The addition of surface treated poly (methyl methacrylate), in the present form, to acrylic resin cannot be recommended as a method of reinforcement.
The effect of aging four commercially-available dental composites in water or ethanol at 37TC for... more The effect of aging four commercially-available dental composites in water or ethanol at 37TC for periods of up to 28 days was assessed by measuring changes in the materials' plane-strain fracture toughness (KIC). The results, obtained by means of a mini Short Rod Fracture Toughness Test specimen design, suggest that while water aging does not produce significant changes in KIC, aging in ethanol does cause significant increases in fracture toughness for three of the four dental composites studied. In view ofpreviously-reported loss of wear resistance for dental composites aged in ethanol solutions, the present study emphasizes the difficulties in usingfracture toughness to predict wear properties. J Dent Res 66 : 722-726, March, 1987
... testing, however, should take into account the possibility of in vivo material degradation an... more ... testing, however, should take into account the possibility of in vivo material degradation and should recognize that ana-tomical constraints ... These standard tests include compact tension4-6, single-edge notch three-point bend (SEN)'-'' double-torsion (DT)"*'2, tapered cleavage ...
The clinical performance of light polymerised dental composites is greatly in#uenced by the quali... more The clinical performance of light polymerised dental composites is greatly in#uenced by the quality of the light-curing unit (LCU) used. Commonly used halogen LCUs have some speci"c drawbacks such as decreasing of the light output with time. This may result in low degree of monomer conversion of the composites with negative clinical implications. Previous studies have shown that blue-light-emitting diode (LED) LCUs have the potential to polymerise dental composites without having the drawbacks of halogen LCUs. Despite the relatively low irradiance of current LED LCUs, their e$ciency is close to that of conventional halogen LCUs with more than twice the irradiance. This phenomenon has not been explained fully yet. Hence, more tests of the LED LCU's e!ectiveness and of the mechanical properties of oral biomaterials processed with LED LCUs need to be carried out. This study investigates the #exural properties of three di!erent composites with three di!erent shades, which were polymerised with either a commercial halogen LCU or an LED LCU, respectively. In most cases no signi"cant di!erences in #exural strength and modulus between composites polymerised with a halogen LCU or an LED LCU, respectively, were found. A simple model for the curing e!ectiveness based on the convolution absorption spectrum of the camphorquinone photoinitiator present in composites and the emission spectra of the LCUs is presented.
Saliba E, Abbassi-Ghadi S, Vowles R, Camilleri J, Hooper S, Camilleri J. Evaluation of the streng... more Saliba E, Abbassi-Ghadi S, Vowles R, Camilleri J, Hooper S, Camilleri J. Evaluation of the strength and radiopacity of Portland cement with varying additions of bismuth oxide.
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Papers by Richard Vowles