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Effect of the curing cycle on some properties of a poly methylmethacrylate denture base material
Quarterly
Dental
81
Review
orders from the previous pattern, which correlates well with clinical observation of the wear of dentures, to a situation where acrylic/acrylic wore least and porcelain/ porcelain the most. Such abrasive conditions were therefore considered unrelated to clinical performance. Results in water and mild abrasive environments showed that porcelain occlusal surfaces should retain their glaze where they oppose acrylic resin antagonists in dentures. Acrylic/acrylic wore approximately seven times more than porcelain/porcelain, a result which is consistent with clinical findings. D. J. Setchell
JAGGER R. G. Effect of the curing cycle on some properties
of a polymethylmethacrylete denture base material, J. Oral RehabiL 5 (1978) 151-157. Four different curing cycles were used to obtain samples of clear Kallodent 333 denture base resin. The polymer structure, molecular weight, molecular weight distribution, residual monomer content, hardness, tensile strength and water sorption of the specimens were all determined. No correlation was observed between curing cycles and polymer structure. The extent to which polymer particles dissolved in the monomer did not appear to be influenced so that it appeared that the polymerization state of the interstitial material was responsible for differences in properties of the cured samples. A cycle of 7 hours at 70°C followed by 1 hour at 100°C was recommended to produce the best physical properties, which coincided with the smallest residual monomer content.
not support fungal growth but it did not exert any inhibitory effect on growth on adjacent agar culture medium. Viscogel containing nystatin completely inhibited growth for 3 weeks (500 000 units nystatin per 3-1 g Viscogel) or longer (1 000 000 units). For undetermined reasons, amphotericin B, which was potently antifungal when applied alone, was inactivated by mixing with Viscogel. The authors concluded that the addition of crushed nystatin tablets to tissue conditioners should be a recommended practice in the treatment of denture stomatitis. D. J. Setchell
ANDREASEN
Nitinol wire (1978) 471.
R. E. G. F. and MORROW analyzed, Dent. Absfr. 29
Nitinol (ni-nickel, ti-titanium, nolNaval Ordnance Laboratory) wire has physical properties quite different from the conventional stainless steel wire used for orthodontic archwire fabrication. It is capable of being deflected over a very wide range without permanent deformation. Thus heavy archwires of nitinol can be fully inserted into bracket slots at an early stage, bringing about simultaneous rotation, levelling, tipping and torquing over a wide range of action without patient discomfort. Andrew Richardson
ENDODONTICS
D. J. Setchell
R. L. and BARKMEIER W. W. testing, Dent Abstr. 23 (1978)
COOLEY
Pulp THOMAS
C. J. and NUTT
G. M. properties
of Viscogel, alone and combined with nystetin and amphotericin 6, J. Oral Rehabil. 5 (1978) The
167-l
in vitro
fungicidal
72.
Three species of Candida were exposed in vitro to the tissue conditioner Visco-gel, alone and in combination with crushed nystatin and amphotericin B tablets at various concentrations. Visco-gel itself did
415417. In the light of inaccurate diagnoses arising from electric pulp testing, thermal testing is recommended. Cold testing can be carried out with dichlorotetrafluoroethane on a cotton pellet, and heat testing with a Burlew wheel, which is a rubber wheel which produces a significant rise in temperature when applied to a tooth. Andrew
Richardson
Dental
81
Review
orders from the previous pattern, which correlates well with clinical observation of the wear of dentures, to a situation where acrylic/acrylic wore least and porcelain/ porcelain the most. Such abrasive conditions were therefore considered unrelated to clinical performance. Results in water and mild abrasive environments showed that porcelain occlusal surfaces should retain their glaze where they oppose acrylic resin antagonists in dentures. Acrylic/acrylic wore approximately seven times more than porcelain/porcelain, a result which is consistent with clinical findings. D. J. Setchell
JAGGER R. G. Effect of the curing cycle on some properties
of a polymethylmethacrylete denture base material, J. Oral RehabiL 5 (1978) 151-157. Four different curing cycles were used to obtain samples of clear Kallodent 333 denture base resin. The polymer structure, molecular weight, molecular weight distribution, residual monomer content, hardness, tensile strength and water sorption of the specimens were all determined. No correlation was observed between curing cycles and polymer structure. The extent to which polymer particles dissolved in the monomer did not appear to be influenced so that it appeared that the polymerization state of the interstitial material was responsible for differences in properties of the cured samples. A cycle of 7 hours at 70°C followed by 1 hour at 100°C was recommended to produce the best physical properties, which coincided with the smallest residual monomer content.
not support fungal growth but it did not exert any inhibitory effect on growth on adjacent agar culture medium. Viscogel containing nystatin completely inhibited growth for 3 weeks (500 000 units nystatin per 3-1 g Viscogel) or longer (1 000 000 units). For undetermined reasons, amphotericin B, which was potently antifungal when applied alone, was inactivated by mixing with Viscogel. The authors concluded that the addition of crushed nystatin tablets to tissue conditioners should be a recommended practice in the treatment of denture stomatitis. D. J. Setchell
ANDREASEN
Nitinol wire (1978) 471.
R. E. G. F. and MORROW analyzed, Dent. Absfr. 29
Nitinol (ni-nickel, ti-titanium, nolNaval Ordnance Laboratory) wire has physical properties quite different from the conventional stainless steel wire used for orthodontic archwire fabrication. It is capable of being deflected over a very wide range without permanent deformation. Thus heavy archwires of nitinol can be fully inserted into bracket slots at an early stage, bringing about simultaneous rotation, levelling, tipping and torquing over a wide range of action without patient discomfort. Andrew Richardson
ENDODONTICS
D. J. Setchell
R. L. and BARKMEIER W. W. testing, Dent Abstr. 23 (1978)
COOLEY
Pulp THOMAS
C. J. and NUTT
G. M. properties
of Viscogel, alone and combined with nystetin and amphotericin 6, J. Oral Rehabil. 5 (1978) The
167-l
in vitro
fungicidal
72.
Three species of Candida were exposed in vitro to the tissue conditioner Visco-gel, alone and in combination with crushed nystatin and amphotericin B tablets at various concentrations. Visco-gel itself did
415417. In the light of inaccurate diagnoses arising from electric pulp testing, thermal testing is recommended. Cold testing can be carried out with dichlorotetrafluoroethane on a cotton pellet, and heat testing with a Burlew wheel, which is a rubber wheel which produces a significant rise in temperature when applied to a tooth. Andrew
Richardson