Various factors are required to be taken into consideration for a successful endodontic treatment. Of these factors, the most important one appears to be an accurate measurent of the root canal length. Without this measurment being made, no accurate lengths an endodontic treatment work can be determined and therefore the treatment will naturally become a hit or miss resulting in under- or over-instrumention, under- or over-filling, and the efforts of dentists are not properly rewarded.
Those authors developed the Sono-Explorer utilizing low-frequency oscillation in 1972, and has demonstrated as a thorough experiments conducted so far that root canal lengths can be accurately and electrically measured. In the following, those authors will make a report on a follow up study of the results of the endodontic treatment basad on the measurement of root canal length by this method.
In this experiment, lengths of 66 infected root canals which had undergone periapical pathosis before the treatment were accurately measured by the Sono-Explorer before root canal filling. Furthermore, for the purpose of comparison with the results achieved by other reporters, filling within 0～－1.5mm from the root apex when examined by X-ray photographs was defined as flush filling, withtn −1.6～−3.0mm as underfilling, and within ＋0.1～＋1.5mm as overfilling.
The following conclusion was obtained as a result of examination of the results over time intervals of from 1 months to 20 years on the basis of the examination of X-ray photographs.
1. In the case of root filling which were regarded as underfilling or flush filling, apical radiolucencies began to be recognized in one month after filling, and the rate of apical radiolucencies increased with the passage of time. However, in the cases of which was regarded as cases of overfilling, it took time until that apical radiolucencies were recognized, and in some cases no apical radiolucencies appeared.
2. So far as the conditions of root canal filling as examined by X-ray photographs were concerned, the rate of successful treatment was 90.4% for underlining. 94.5% for flush filling and a low 50% for overfilling. Thus, there was no much difference between underfilling and flush filling, but there was a significant diffence between these and overfilling.
3. Generally speaking, the rate of successful root canal filling was 87.8% for the cases of filling which did not exceed the apical foramen but reached the apical constriction, and 95.3%, in the cases of filling in which the apical radiolucencies were occurring, are included. Furthermore, excluding the cases of intentional overfilling, the rate was as high as 98%.
4. The electric root canal measurement method is more accurate than the X-ray measurement method, and an accurate measurement of root canal length is considered a major key to a successful endodontic treatment.
Diammine silver fluoride have been applied for effective prevention and arrest of dental caries in noncooperative infants and children. But it produceol unpleasant smelling and bad taste. The purpose of this study was to mask its smelling and taste by the sweet tooth paste.
The materials were diammine silver fluoride (38% Ag(NH3)2F solution) and Chanariena dental paste 100 for child®. The method was brushing up the teeth by the tooth paste, so the child's mouth smelled sweet, and following the diammine silver fluoride was applied.
The children who had the dental caries lesions in deciduous teeth were divided into experimental and control group. All subjects of the experimental group have received topical application of 38 per cent diammine silver fluoride after brushing with the tooth paste, while subject of the control group received topical application without the dental paste.
It was decided on an index of discomfort to four grade assessment. As compared the two groups, it was improved effectively. Therefore, by this method it was found that it could applied easily and effectively to the infants and children.
The purpose of this study was to measure the transmission rate of Ga-Al-As semiconductor laser through enamel and dentine.
Nine extracted human parmanent teeth (3 anterior teeth, 3 premolar teeth and 3 molar teeth) were used. 40mW Ga-Al-As semiconductor laser was irradiated on the cervical surface of buccal half of the crown. The transmitted laser was measured with a phtodiode put on the pulpal side. Then, the thickness of the crown was reduced successively by grinding the teeth from the pulpal side and the relationship betweeen the transmission rate and tooth thickness was investigated.
As a result, laser transmission showed an exponential increase according to the reduction of tooth thickness. The mean percent of laser transmission was 38.10% in 0.50mm, 28.04% in 0.75mm, 21.79% in 1.00mm, 16.38% in 1.25mm, 13.40% in 1.50mm, 9.82% in 1.75mm, 6.76% in 2.00mm, 4.95% in 2.25mm, 4.17% in 2.50mm, 4.42% in 2.75mm, 3.91% in 3.00mm, 3.01% in 3.25mm, 2.92% in 3.50mm thickness.
The curve of this root canal is one thing which makes the endodontic treatment difficult.
Careless operation of tools in the root canal causes breakage of tool, ledge, elbow, perforation and zip and the operation ends in failure.
Therefore, there is the method which makes the curved root canal atraight as far as possible by making the root canal to the under part of the curve (near the apex of root) for simplification and high efficiency.
But, can it be understood that the elimination of the dentin which does not yield again is continusd so under the name of simplification and high efficiency?
I would like to explain the opian carrier method which I operate under consideration of the preservation of the tooth substance, by giving several clinical examples.
Comparison between dental detergents with medical detergents and a detergent made by myself on the power to remove grease and proteins. The result is that medical detergents and the one made by myself are the better of dental detergents and the price of one made by myself is cheaper.
Dental antioxidizing detergents for small dental instruments contain the minimum of disinfectant solutions not enough to eliminate hepatitis, AIDS virus and another contagious diseases, and its use as disinfectant incorrect. Their cleaning action is a too poor. That is why I do not recomend the use of dental detergents.