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Proteolipid and calculus matrix calcification in vitro,
254
Journal of Dentistry, Vol. ~/NO. 3
PHARMACOLOGY CULLITON
AND THERAPEUTICS
6. J.
Drug resistance growing worse, Dent Absrr. 22 (1977) 1%. There are fears that penicillin-resistant gonococci may spread their anti-penicillin enzymes to other organisms such as meningococci. Resistance is transferred from organism to organism by packages of genes called R-factors. By a process of conjugation, R-factors pass from bacterium to bacterium, transferring genetic information in aclassic, natural case of recombinant DNA. Antibiotic usageshould be limited severely. Andrew Richardson BRINCKER
H.
Miconazole in oral candidiasis, Proc. R. Sot. Med. 70 (1977) Suppl. 1. Treatment with antibiotics, cytostatics and corticosteroids has been considered to be responsible for the steadily increasing number of systemic fungal infections observed during the past 20 years, especially in patients with leukaemia. The author started using miconazole topically in the form of tablets for the treatment of oral candidiasis in August 1972. The preliminary results indicated a high rate of clinical cure in a very few days. Patients undergoing chemotherapy for leukaemia, lymphoma or a solid tumour who had clinically obvious oral candidiasis (verified by positive cultures of Candida albicans from the oral mucosa) were observed in this study. The treatment was given as 1 tablet of 250 mg of miconazole four times daily, allowed to dissolve slowly in the mouth. After gradual dissolution of the tablet, the drug was swallowed. Removable dentures, if any, were placed in 150 ml of water in which 1 tablet of miconazole was dissolved. The dentures were treated for at least 1 hour simultaneously with the oral application of the drug. The protocol prescribed the treatment to be continued for at least 2 days after clinical cure of the candidiasis. Mycological cure was established by a negative culture from the oral mucous membrane on the day after the end of miconazole treatment. Thirty-five episodes of oral candidiasis were treated in 24 patients. The median
age of the patients was 55 years, and all the patients were strongly predisposed to fungal infections because of granulocytopenia or simultaneous treatment with prednisolone or antibiotics. Clinical cure was observed in all 35 cases, the mean treatment time being 5 days, thus clinical cures were obtained in 2-3 days. In many cases even heavy disseminated fungal coatings disappeared after only 1 day of treatment. The mean disease-free interval between attacks of fungal infection was 14 days (while the patients remained predisposed to fungal infection to the same degree). Compared with studies of nystatin and amphoteracin B, miconazole givesthe highest frequency of clinical and mycological cure in spite of the shortest treatment time. This is probably because miconazole is absorbed from the gastro-intestinal tract. The tablets used in this study had an unpleasant taste; however, this has now been eliminated, and there are no other side-effects ascribable to miconazole. P. A. E. Banks MUMFORD
J. S.
Transcutaneous neural stimulation for relief of orofacial pain, Dent. Abstr. 22 (1977) 105. Electrical stimulators where the amplitude, frequency and duration of the stimulus can be regulated by the patient are available. One electrode is applied to the painful area and the other is applied wherever is convenient. The current amplitude is increased until the patient feels a ‘satisfying’ sensation in the painful area. When this sensation fades, the patient again adjusts the amplitude. Andrew Richardson
RESEARCH AND CLINICAL ENNEVER J.,VOGEL and PAOLOSKI F. B.
PRACTICE
J. J., RIGGAN
L. J.
Proteolipid and celculus matrix calcification in vitro, J. Dent Res. 56 (1977) 140142. Total lipid derived from pooled calculus samples was separated into crude phospholipid and non-polar lipid by acetone precipitation.
265
Quarterly Dental Review
Crude phospholipid was fractionated by column chromatography. The first ultraviolet-light-absorbing fraction, indicative of protein content, represented approximately 25 per cent of the crude phospholipid by weight. This fraction induced calcification in metastable calcium phosphate solutions. Ashing of the product gave X-ray diffraction maximums for apatite. Proteolipid initiates calculus matrix calcification. A similar macromolecule nucleates calcification by the micro-organism 6. matruchotii. This micro-organism might be used for the preliminary evaluation of calculus preventatives which act by interfering with calcification initiation. Andrew Richardson
ATKINSON
H. F. and RALPH
W. J.
In vitro strength of the human periodontal ligament, J. Dent Res. 56 (1977) 48-52. This paper set out to study the physical properties of the periodontal ligament since most of the work done in this field has been on the histological aspects. Extrusion loads were applied to the periodontal membrane on freshly extracted teeth where adherent bone fragments remained and also on post-mortem specimens where the alveolar bone had been dissected out. A stabilizing load of O-2 kg was applied before incremental loads were added. It was found that extension of the ligament was proportional to the load applied up to the elastic limit, after which plastic deformation occurred until the point of rupture was reached. The rate of loading did not affect the elastic properties nor did repeated loading below the elastic limit. When rupture occurred this took place within the ligament and not within bone or cementurn. When intrusion loads wereapplied to postmortem specimens, no movement of the tooth relative to alveolar bone was seen at loads greater than 2 kg up to a maximum of 20 kg. When the maximum load a lower first permanent molar could withstand was estimated by calculating the total area of the periodontal ligament, a value of 192.4 kg was found. The maximum measured biting load has previously been reported as 73 kg.
It was felt that although some fibres will not be available for resisting such loads where root curvature is present, the periodontal ligament should be well capable of withstanding the maximum biting load without injury. G. A. Smith
MEURMAN
J. H. and ASIKAINEN
Rehardening of acid etched Abstr. 22 (1977) 185-186.
M.
enamel,
Dent
Specimens from freshly extracted bovine incisors were prepared for mounting on the buccal surfaces of upper first and second molars of 40 dental students. Half of each specimen was acid-etched, the other half serving as a control. The specimens were exposed to the oral environment for l-23 days. Thirteen additional specimens were remineralized separately in vitro. The specimens were then studied with surface microhardness indentation apparatus and scanning electron microscopy. Etched enamel rehardened up to 83.7 per cent of the original value when exposed in the mouth but only up to 74 per cent in vitro. Electron microscopy revealed pores and other defects of the repaired surface. Unnecessary conditioning of intact enamel by acid solutions should be avoided. Andrew Richardson
WINER
H. J.
Use of the Heimlich maneuver in the dental office, Dent. Abstr. 22 (1977) 284-285. Although aspiration of foreign objects may not occur daily in a dental practice, it is an ever-present risk. If, after hyperextending the patient’s neck and thrusting the mandible forwards, expiration of air does not occur in spite of laboured breathing, an obstruction is present. The first rescuer sits astride the patient in the chair and the second rescuer turns the patient’s head to the side and prepares to evacuate ejected material. The first rescuer places both hands one over the other, between the xiphoid process and the umbilicus and suddenly presses inwards and upwards. The diaphragm is forced upwards, residual air is expelled from the lungs and the obstruction is expelled. Andrew Richardson
Journal of Dentistry, Vol. ~/NO. 3
PHARMACOLOGY CULLITON
AND THERAPEUTICS
6. J.
Drug resistance growing worse, Dent Absrr. 22 (1977) 1%. There are fears that penicillin-resistant gonococci may spread their anti-penicillin enzymes to other organisms such as meningococci. Resistance is transferred from organism to organism by packages of genes called R-factors. By a process of conjugation, R-factors pass from bacterium to bacterium, transferring genetic information in aclassic, natural case of recombinant DNA. Antibiotic usageshould be limited severely. Andrew Richardson BRINCKER
H.
Miconazole in oral candidiasis, Proc. R. Sot. Med. 70 (1977) Suppl. 1. Treatment with antibiotics, cytostatics and corticosteroids has been considered to be responsible for the steadily increasing number of systemic fungal infections observed during the past 20 years, especially in patients with leukaemia. The author started using miconazole topically in the form of tablets for the treatment of oral candidiasis in August 1972. The preliminary results indicated a high rate of clinical cure in a very few days. Patients undergoing chemotherapy for leukaemia, lymphoma or a solid tumour who had clinically obvious oral candidiasis (verified by positive cultures of Candida albicans from the oral mucosa) were observed in this study. The treatment was given as 1 tablet of 250 mg of miconazole four times daily, allowed to dissolve slowly in the mouth. After gradual dissolution of the tablet, the drug was swallowed. Removable dentures, if any, were placed in 150 ml of water in which 1 tablet of miconazole was dissolved. The dentures were treated for at least 1 hour simultaneously with the oral application of the drug. The protocol prescribed the treatment to be continued for at least 2 days after clinical cure of the candidiasis. Mycological cure was established by a negative culture from the oral mucous membrane on the day after the end of miconazole treatment. Thirty-five episodes of oral candidiasis were treated in 24 patients. The median
age of the patients was 55 years, and all the patients were strongly predisposed to fungal infections because of granulocytopenia or simultaneous treatment with prednisolone or antibiotics. Clinical cure was observed in all 35 cases, the mean treatment time being 5 days, thus clinical cures were obtained in 2-3 days. In many cases even heavy disseminated fungal coatings disappeared after only 1 day of treatment. The mean disease-free interval between attacks of fungal infection was 14 days (while the patients remained predisposed to fungal infection to the same degree). Compared with studies of nystatin and amphoteracin B, miconazole givesthe highest frequency of clinical and mycological cure in spite of the shortest treatment time. This is probably because miconazole is absorbed from the gastro-intestinal tract. The tablets used in this study had an unpleasant taste; however, this has now been eliminated, and there are no other side-effects ascribable to miconazole. P. A. E. Banks MUMFORD
J. S.
Transcutaneous neural stimulation for relief of orofacial pain, Dent. Abstr. 22 (1977) 105. Electrical stimulators where the amplitude, frequency and duration of the stimulus can be regulated by the patient are available. One electrode is applied to the painful area and the other is applied wherever is convenient. The current amplitude is increased until the patient feels a ‘satisfying’ sensation in the painful area. When this sensation fades, the patient again adjusts the amplitude. Andrew Richardson
RESEARCH AND CLINICAL ENNEVER J.,VOGEL and PAOLOSKI F. B.
PRACTICE
J. J., RIGGAN
L. J.
Proteolipid and celculus matrix calcification in vitro, J. Dent Res. 56 (1977) 140142. Total lipid derived from pooled calculus samples was separated into crude phospholipid and non-polar lipid by acetone precipitation.
265
Quarterly Dental Review
Crude phospholipid was fractionated by column chromatography. The first ultraviolet-light-absorbing fraction, indicative of protein content, represented approximately 25 per cent of the crude phospholipid by weight. This fraction induced calcification in metastable calcium phosphate solutions. Ashing of the product gave X-ray diffraction maximums for apatite. Proteolipid initiates calculus matrix calcification. A similar macromolecule nucleates calcification by the micro-organism 6. matruchotii. This micro-organism might be used for the preliminary evaluation of calculus preventatives which act by interfering with calcification initiation. Andrew Richardson
ATKINSON
H. F. and RALPH
W. J.
In vitro strength of the human periodontal ligament, J. Dent Res. 56 (1977) 48-52. This paper set out to study the physical properties of the periodontal ligament since most of the work done in this field has been on the histological aspects. Extrusion loads were applied to the periodontal membrane on freshly extracted teeth where adherent bone fragments remained and also on post-mortem specimens where the alveolar bone had been dissected out. A stabilizing load of O-2 kg was applied before incremental loads were added. It was found that extension of the ligament was proportional to the load applied up to the elastic limit, after which plastic deformation occurred until the point of rupture was reached. The rate of loading did not affect the elastic properties nor did repeated loading below the elastic limit. When rupture occurred this took place within the ligament and not within bone or cementurn. When intrusion loads wereapplied to postmortem specimens, no movement of the tooth relative to alveolar bone was seen at loads greater than 2 kg up to a maximum of 20 kg. When the maximum load a lower first permanent molar could withstand was estimated by calculating the total area of the periodontal ligament, a value of 192.4 kg was found. The maximum measured biting load has previously been reported as 73 kg.
It was felt that although some fibres will not be available for resisting such loads where root curvature is present, the periodontal ligament should be well capable of withstanding the maximum biting load without injury. G. A. Smith
MEURMAN
J. H. and ASIKAINEN
Rehardening of acid etched Abstr. 22 (1977) 185-186.
M.
enamel,
Dent
Specimens from freshly extracted bovine incisors were prepared for mounting on the buccal surfaces of upper first and second molars of 40 dental students. Half of each specimen was acid-etched, the other half serving as a control. The specimens were exposed to the oral environment for l-23 days. Thirteen additional specimens were remineralized separately in vitro. The specimens were then studied with surface microhardness indentation apparatus and scanning electron microscopy. Etched enamel rehardened up to 83.7 per cent of the original value when exposed in the mouth but only up to 74 per cent in vitro. Electron microscopy revealed pores and other defects of the repaired surface. Unnecessary conditioning of intact enamel by acid solutions should be avoided. Andrew Richardson
WINER
H. J.
Use of the Heimlich maneuver in the dental office, Dent. Abstr. 22 (1977) 284-285. Although aspiration of foreign objects may not occur daily in a dental practice, it is an ever-present risk. If, after hyperextending the patient’s neck and thrusting the mandible forwards, expiration of air does not occur in spite of laboured breathing, an obstruction is present. The first rescuer sits astride the patient in the chair and the second rescuer turns the patient’s head to the side and prepares to evacuate ejected material. The first rescuer places both hands one over the other, between the xiphoid process and the umbilicus and suddenly presses inwards and upwards. The diaphragm is forced upwards, residual air is expelled from the lungs and the obstruction is expelled. Andrew Richardson