GB2199839A - Radioopaque impression materials for inspecting the root canal - Google Patents

Radioopaque impression materials for inspecting the root canal Download PDF

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GB2199839A
GB2199839A GB08728567A GB8728567A GB2199839A GB 2199839 A GB2199839 A GB 2199839A GB 08728567 A GB08728567 A GB 08728567A GB 8728567 A GB8728567 A GB 8728567A GB 2199839 A GB2199839 A GB 2199839A
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root canal
impression material
radioopaque
powders
substance
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GB8728567D0 (en
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Atsumu Miyahara
Hachiro Sasaki
Shunichi Futami
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GC Corp
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GC Dental Industiral Corp
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
    • C08K3/013—Fillers, pigments or reinforcing additives
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/50—Preparations specially adapted for dental root treatment
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/90—Compositions for taking dental impressions

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  • Health & Medical Sciences (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Epidemiology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Dental Preparations (AREA)

Description

p 11 r 2199839 RAD100PAQUE IMPRESSION MATERIALS FOR INSPECTING THE ROOT
CANAL The present invention relates to a radioopaque impression material for inspecting the root canal, which is used as the material to enable easy insf action and appreciation of the full-aspect of the rool canal for exact treatment, when performing endodontics -for the preservation and retainment of teeth in odontotherapy.
A natural tooth is of the structure comprising outside enamel and inside dentine, in which there is further the root canal having the dental pulp (nerves) therein. However precise a denture (a false tooth) may be to the wearer, it is in no way superior to a natural tooth. For that reason, endodontics to recover a natural tooth holds a vital position in dental therapy, and is a remedy as fundamental and important as periodontology.
F r treating pulpal diseases such as endodontitis caused by pulpal caries or tooth devitalization caused by pulpal gangrene or necrosis, endodontics is performed to retain and make effective use of natural teeth as long as possible.
Endodontics is a remedy for the root canal, which has for its object to appropriately treat the interior of the root canal, the dental pulp of which is devitalized.
Such clinical treatment of the root canal involves the following three remedial processes.
1. Probing of the configuration, and measuring the size, of the root canal.
2. Preparation and cleaning of the root canal.
0 3. Root canal filling First of all, the state of the root canal, parodontium, etc. are appreciated by roentgenography to determine a remedial scheme. Following the remedial scheme, the dental pulp is removed with the use of a spiral bar called a broach. Afterwards, the interior of the root canal is cleaned to a completely aseptic condition to enlarge and prepare it, and is then usually filled with a gutta-percha point or a paste agent to fill it for complete sealing. In such endodontics, that is to say, the treatment of the root canal, roentgenography and roentgenological examination are now generally performed as the means effective to get hold of the complicated configuration of the root canal.
Prior to the enlargement and cleaning of the root canal, it is required to observe and consider the configuration and length of the root canal and the state of its lateral branches and accessory root canals in more detail. An X-ray photograph is a product of light and shadow made by roentgenopaque and transparent substances. Treatments are now performed by getting two-dimensional hold of a tooth or the root canal, each of a three-dimensional configuration, by the observation of an indistinct Xray photograph and imaging the root canal of a three-dimensional configuration through high-degree knowledge and expertness. For such appropriate treatment of teeth, it is absolutely required to get accurate hold of the configuration, number and length of the root canal and the distribution of its lateral branches and accessory root canals.
Next, the root canal is cut and enlarged with the use of a reamer and Kand H-type files for polishing and cleaning. A guttapercha point or a root canal filling material paste is filled as the root canal filling agent in the thus formed root canal void for complete sealing of the root canal and closing of the apical foramen.
i 4 4 1 p In this manner, the treatment of the root canal with endodontics is completed.
The object of the treatment of the root canal in endodontics is to fill the root canal and free it of any dead space by filling of a solid root canal filling material such as gutta-percha and silver points, or pasty root canal filling materials composed mainly of calcium hydroxide and zinc oxide engenol. The requirements to this end are the proper preparation and complete cleaning of the root canal. For the proper preparation and complete cleaning of the root canal, it is required to get hold of the configuration, number and length of the root canal and the distribution of its lateral branches and accessory root canals by the observation of a plane X-ray photograph. However, it has been impossible to catch hold of. the complicated state of the root canal even with recourse to high-degree expertness and experience. Further, the cubic figure of the root canal cannot diredly be appreciated, since an X-ray photograph is twodimensional. Considerable difficulty has been encountered in the treatment of the root canal of such a complicated configuration, and makes it impossible to perform perfect root canal filling. This is responsible for recurrence of dental caries or periodontal diseases after the treatment.
Further, the X-ray photograph of teeth is now still of unclear roetgenopaqueness. The length of the root canal may be measured by the insertion of a file, etc. thereinto, but it is impossible to get hold of the width and configuration of root canal. Nonetheless, not until now is any roentgenopaque impression material effective for root canal examinations found. For exact endodontics, it is required to make direct or quasi-direct observation of the interior of the root canal before and after operation.
It has now been found that an impression material for the inspection of the root canal can be obtained by imparting roentgenopaque properties to a rubbery and elastic impression material for dental purposes, which can give a distinct roentgenogram of the complicated interior of the root canal and be poured into the details of the root canal so as to obtain a three-dimensional figure thereof.
More specifically, a silicone impression material to which roentgenopaque properties are imparted is poured into the root canal of a tooth before and after operation to compare a roentgenogram with a cubic impression mould moulded from the root canal and get threedimensional hold of the state of the root canal, whereby the root canal can be enlarged and cleaned. The impression material of the present invention is sufficiently helpful in determining whether or not the enlargement of the root canal is feasible, thereby allowing easy correction of the root canal, which has heretofore been unfeasible in the prior art.
The radioopaque substance acts as the filler, and may be used in place of, or together with, a conventional filler.
For room - temperature-setting, rubbery and elastic impression materials for dental purposes, use is made of condensation and addition polymerization type silicone impression materials as well as polysulfide and polyether impression materials. The polysulfide impression material is less susceptible to setting and shows relatively large elastic deformation. In the case of moulding (impression-taking) of a detail line such as the root canal, therefore, attention should be paid to the rate of removal of that impression material, since it is hard to reproduce the precise state of the root canal, partly because difficulty is involved in the 9 0 L removal of that material from within the root capal because that material is pulled and elongated.
Referring to. the polyether impression material, since difficulty is experienced in pouring it into the root canal due to the absence of flowability, a certain pressure is needed. Further, care should be taken in using the polyether impression material as the radic,opaque impression material for the insepction of the root canal, since it shows high water absorption and is cured into a hard body, which is easily torn off and causes a slight drop in the accuracy of a detail line mould such as a root canal mould. However, the silicone impression materials are optimum - for the radioopaque impression material for the inspection of theroot canal according to the present invention, since it excels in elasticity and hydrophobic nature and is harmless to the human body. The roomtemperature-setting, rubbery and elastic impression material for the inspection of the root canal usable in the present invention should preferably be based on the condensation and addition, polymerization types. It is possible for the first time to take, an X-ray photograph of the details of the root canal by imparting roentgenopaqueness to these two types of the dental silicone impression materials and filling them into the details of the root canal. After setting, the set body can easil be removed to obtain a cubic figure of the configuration of the root canal, etc., by means of which the enlargement and preparation of the root canal can easily be observed and ascertained.
The radioopaque materials used in the present invention act as the fillers, and may be used in place of, or together-with, the conventional fillers, but should not be harmful and toxic to teeth and periodontium. Hence, a radicopaque substance having a solubility exceeding 0.2 grams per 100 mO of water at 2TC is. not freterred, partly because teeth and periodontium are adversely affected by its and partly dissolution, and partly because it hinders the setting reaction of the silicone impression material.
The radioopaque substance fit for the purpose of the present invention is -?referably an inert substance showing a solubility of up to 0.2 grams per 100 mQ of water at WC. Included in the substances which are of high roentgenopaque properties, show a solubility of up to 0.2 grams per 100 mQ of water at WC and are untoxic and harmless, are powders of metals such as zinc, ytterbium, yttrium, gadolinium, zirconium, strontium, tungusten, tantalum, niobium, molybdenum and lanthanum; finely divided powders of alloys of such metals; oxides such as yttrium oxide, bismuth oxide, ytterbium oxide, tungusten oxide, niobium oxide, tantalum oxide and molybdenum oxide; fluorides such as strontium fluoride, yttrium fluoride, bismuth fluoride, lanthanum fluoride and ytterbium fluoride; sulfates such as barium sulfate and strontium sulfate; carbonates such as bismuth oxycarbonate and strontium carbonate; tungstates such as calcium tungstate; and carbides such as tungsten carbide, molybdenum carbide, niobium carbide, tantalum carbide and zirconium carbide.
The concentration of the radioopaque substance should be such that the radioopaque impression material for the inspection of the root canal shows suitable flowability and roentgenopaque 'properties. In this connection, however, it should be noted that the flowability and roentgenopaque properties tend to be contrary to each other because of the radioopaque substance being in the form of finely divided powders, i. e., in the solid form. When the radicopaque substance is too small in. quantity, no effective roentgenopaque properties are obtained. In particular,.it is required that the radioopaque substance used in the present invention is distinctively distinguishable from enamel, and be readily pourable into the details of the root canal by means of a spiral tool called a lentulo. An excessive amount of the radiciopaque 1 - 6 W substance is unfit for the purpose of the present invention, since difficulty is encountered in allowing it to flow into the details of the root canal.
Hence, when the radioopaque substance is used in an amount of less than 20.0 % by weight with respect to room -temperature setting silicone impression material, the boundary of the impression material poured into the root canal's void and the root canal's wall becomes so indistinct that it is especially difficult for the dentist to get hold of the complicated configuration and dimensions of the root canal and make exact inspection thereof. It is required, there fore, that, in order to obtain effective roentgvnopaque properties, the radioopaque substance used in the present invention is added to the room-temperature-setting impression material in an amount of at least 20.0 % by weight.
When the amount of the radioapaque substance with respect to a room -temperature-setting silicone impression material exceeds 75.0 % by weight, it is zlifficult to obtain any distinct roentgenogram of the details of the root canal, since that impression material loses its flowability, that is one function indispensible thereto, and does not flow into the details of the root canal.- Moreover, because of the presence of too large an amount of the finely divided powders of the ra&oopaque substance, the silicone impression material loses its rubber elasticity to such an extreme degree that it becomes brittle and tends to be easily torn off, thus making it very difficult to remove the cured impression from within the root canal.
It is reqcLired, therefore, that the radioopaque substance be used in an a mount of up to 75.0 % by weight with respect to the room temperature-setting impression material so as to permit it to flow into the details of the root canal. In other words, the concentration of the radicopaque substance enough to show effective - 7- roentgenopaque properties and flow into the details of the root canal should be limited to a range of 20.0 % by weight to 75.0 % by weight with respect to the room-temperature-setting impression material. More preferably, the concentration of the radiopaque substance sufficient to show excellent roentgenopaque properties, make a distinct figure of the root canal and render it possible to perform complete root canal treatment is in a range of 25.0 % by weight to 70.0 % by weight with respect to the room temperature-setting impression material.
Further, the mean particle size of the finely divided radi:oopaque substance powders should be such that the flowability permitting the root canal-inspecting impression material to -perform its own function and the effective roentgenopaque properties are assured. The finely divided radioopaque substance powders having a mean particle size of less than 5 x 10-3 microns may be unsuitable, since they give rise to a considerable decrease in the flowability of the impression material due to their large specific surface area, and their amount to be contained in the impression material is reduced to lower the roentgenopaque properties thereof. The finely divided rad; oopaque substance powders having a mean.particle size exceeding 10 micron5may also be unsuitable, partly because it is difficult to pour the root canal-inspecting impression material containing them into the details of the root canal, and partly because when the root canal is moulded (for impression-taking) after setting, the moulded surface tends to roughen, thus making it difficixlt to obtain any fine cubic figure of the details of the root canal. Hence, the mean particle size of the radicopaque substance powders used with the root canal-in ecting impression material should be limited to 5 x 10-3 to 10 micrometers. The shape of the finely divided radtoopaque substance powders is preferably as close to a spherical shape having a reduced w surface area as possible, since the amount thereof to be contained in the impression material is increased.
It is to be understood that these radioopaque substances may be used alone -or in admixture, when incorporated into the room- temperature-setting -n?ress:Lon material.
In general, room -temperature-setting, rubbery and elattic impression material for dental purposes is based on a pasty two- component system comprising a base and a catalyst and a three component system comprising a pasty base-catalyst combination and a liquid reactor. According to the present invention, either one of these systems may be used, and the required quantity of one or two or more radioopaque substances showing a solubility of up to 0.2 grams per 100 mp of water of 201C is incorporated into the room- temperature-setting, rubbery and elastic impression material for dental purposes. On the other hand, the room temperature-setting silicone impression materials for dental purposes usable in the present invention are known ones of the condensation and addition polymerization types comprising the following typical components:
A: Condensation Polymerization Type Silicone Impression Materials a) hydroxydimethylpolYsiloxane having hydroxide groups on its both terminals b) ortho or polyethyl silicate having an ethoxy group as the crosslinker C) organometallic compounds such as dibutyltin acetate, dibutyltin laurate and lead octenate used as the condensation polymer-r,ation catalyst d) fillers suc as diatomaceous earth and silica, and e) coloring material, perfumes, flowability regulators and plasticizers which may be used, if required. - 9- B: Addition Polymerization Type Silicone Impression Materials a) vinylpolymethylsiloxane having a terminated vinyl group? b) hydrogenpolymethylsiloxane having active hydrogen groups on its both terminals, c) addition polymerization catalysts such as platinum base catalysts, d) fillers such as diatomaceous earth and silica, and e) coloring materials, perfumes, flowability regulators and plasticizers which may be used, if required. Examples The present invention will now be explained with reference to the following non-restrictive examples. A: Condensation Polymerization Type Silicone Impression Materials for Inspecting the Root Canal Example 1 Components I Hydroxydimethylpolysiloxane Finely divided barium sulfate powders (having mean particle size of 0.2 micrometers) 100 wt.% The components I were sufficiently mixed and kneaded together for 60 minutes in a mixer to prepare a base.
Components II Vaseline (F?-TM) 20 Dibutyltin laurate 4 Polyethyl silicate 25 Finely divided barium sulfate powders (having a mean particle size of 0.2 micrometers) 50 Red iron oxide 1 wt. % The components II were sufficiently mixed and -kneaded together_ for 60 minutes in a mixer to prepare a catalyst.
The base and catalyst in a weight ratio of 2:1 were mixed on a mixing pad for 30 seconds by means of a spatula. The product was cured in four minutes. Example 2 Components I Hydroxydimethylpolysiloxane Finely divided tungsten oxide powder (having a mean particle size of 0.04 micrometers) 40 wt. % The components I were sufficiently mixed and kneaded together for 45 minutes in a mixer into a base. Components II Vaseline Dibutyltin acetate Finely divided strontium sulfate powders (having a mean particle size of 0.3 micrometers) Polyethyl silicate Red iron oxide 16 4 24 1 wt.
The components II were sufficiently mixed and kneaded together for 30 minutes in a mixer into a catalyst.
The base and catalyst in a weight ratio of 2:1 were mixed on a mixing pad for 30 seconds by means of a spatula. The product was cured in 4.5 minutes.
1 1 12 - Example 3 Components I Hydroxydimethylpolysiloxane Finely divided zinc powders (having a mean particle size of 5.0 micrometers) so wt. % The components I were sufficiently mixed and kneaded together for 60 minutes in a mixer into a base. Components II Vaseline Lead octenate Finely divided bismuth oxycarbonate powders (having a mean paticle size of 0.006 micrometers) Finely divided niobium oxide powders (having a mean particle size of 0.4 micrometers) Tinting red 26.5 28.0 35.0 10.0 0.5 100. 0 wt.
The components II were sufficiently mixed and kneaded together for 45 minutes in a mixer into a catalyst. Components III Ethyl silicate Silicone oil 50 wt. % The components III were sufficiently agitated and mixed together for 10 minutes in a mixer into a reactor.
The base, catalyst and reactor in a weight ratio of 5:2:1 were mixed together on a mixing pad for 40 seconds with the use of a spatula. The product was cured in 5 minutes.
1 1 Comparative Example 1 Components I Hydroxydimethylpolysiloxane 70 Silica (#300) 30 wt. % The components I were sufficiently mixed and kneaded together for 60 minutes in a mixer into a base.
Components II Vaseline 27.5 Dibutyltin laurate 29.0 Polyethyl silicate 23.0 Diatomaceous earth 20.0 Tinting red 0.5 wt. % The components II were sufficiently mixed and kneaded together for 40 minutes in a mixer into a catalyst.
The base and catalyst in a weight ratio of 5:2 were mixed together on a mixing pad for 40 seconds with the use of a spatula. The product was cured in 4.5 minutes.
The testing results of the.impression materials A (Examples 1-3 and Comparative Example 1) are tabulated in Table 1 to be given later. B: Addition PolyTerization Type Silicone Impression Materials for Inspecting the Root Canal Example 4 Component I Vinylpolymethylsiloxane Hydrogenpolymethylsiloxane Finely divided calcium tungstate powders (having a mean particle size of 0.01 micrometers) 38 22 ___40____ 100 wt.% The components I were fifficiently mixed and kneaded together for 60 minutes in a mixer into a base. Components II Vinylpolymethylsiloxane Finely divided yttrium fluoride powders (having a mean"particle size of 0. 016 micrometers) Finely divided tungusten carbide powders (having a mean particle size of 9.6 micrometers) Hexachloroplatinic acid 49.95 25.0 25.0 0.05 The components II were sufficiently mixed and kneaded together for 60 minutes in a mixer into a catalyst.
The base and catalyst in a weight ratio of 1:1 were mixed together on a mixing pad for 30 seconds with the use of a spatula. The product was cured in 4.5 minutes.
Example 5
Component 1 Vinylpolymethylsiloxane Hydrogenpolymethylsiloxane Finely divided lanthanum fluoride powders (having a mean particle size of 0.009 micrometers) Finely divided strontium fluoride powders (having a mean particle size of 0.15 micrometers) 40 wt. % The components I were sufficiently mixed and kneaded together for 60 minutes in a mixer into a base.
- t Composition II Vinylpolymethylsiloxane Finely divided molybdenum oxide powders (having a mean particle size of 0.4 micrometers) Finely divided bismuth fluoride powders (having a mean particle sze of 0.9 micrometers) Rexachloroplatinic acid 39.95 20.0 40.0 0.05 wt. % The components II were sufficiently mixed and kneaded together for 60 minutes into a catalyst.
The. base and catalyst in a weight ratio of 1: 1 were mixed together on a mixing pad for 30 seconds with the use of a spatula. The product was cured in 4.5 minutes. Example 6 Components I Vinylpolymethylsiloxane Hydrogenpolymethylsiloxane Finely.divided bismuth oxide powders (having a mean particle size of 8.5 micrometers) wt. % The components 1 were sufficiently mixed and kneaded together for 60 minutes in a mixer into a base. Components H' Vinylpolymethylsiloxane Finely divided brass powders (having a mean particle size of 3.5 micrometers) Hexachloroplatinic acid Ultramarine 27 18 29.7 70.0 0A6 0.24 100.0 wtA The components II were sufficiently mixed and kneaded together - 15- for 70 minutes in a mixer into a catalyst.
The base and catalyst in a weight ratio of 1:1 were mixed together on a mixing pad for 30 seconds by means of a spatula. The product was cured in 4 minutes. Example 7 Components I Vinylpolymethylsiloxane Hydrogenpolymethylsiloxane Finely divided barium sulfate powders (having a mean particle size of 1.5 micrometers) 35 wt. % The components I were sufficiently mixed and kneaded together for 80 minutes in a mixer into a base.
Components II Vinylpolymethylsiloxane Finely divided yttrium oxide powders (having a mean particle size of 0.5 micrometers) Finely divided calcium tungstate powders (having a mean particle size of 0.1 micrometer) 15.0 Hexachloroplatinic acid 0.05 Ultramarine 0.35 100.0 wtA The components II were sufficiently mixed and kneaded together for 60 minutes in a mixer into a catalyst.
The base and catalyst in a weight ratio of 1:1 were mixed together on a mixing pad.for 30 seconds with the use of a spatula. The product was cured in 5 minutes.
74.6 10.0 4 1 1 CoERarative Example 2 Components I Vinylpolymethylsiloxane Hydrogenpolymethylsiloxane Silica (#300) 47 28 25 100 wtA The components I were sufficiently mixed and kneaded together for 50- minutes in a mixer into a base. Components II Vinylpolymethylsiloxane Silica (#300) Hexachloroplatinic acid 84.95 15.0 0.05 wt.
The components II were sufficiently mixed and kneaded together for 50 minutes in a mixer into a catalyst.
The base and catalyst in a weight ratio of 1:1 were mixed together on a mixing pad for 30 seconds with the use of a spatula. The product was cured in 4.5 minutes.
The testing results of the impression materials B (Examples 4-7 and Comparative Example 2) are tabulated in Table 2 to he givenAater. Table.] - Condensation Polymerization Type Silicone Impression Materials A for Inspecting the Root Canal Sample Example Example Example Comparative 1 2 3 Example I Setting Time 4 min 4.5 min 5 min 4.5 min Roentgenopaqueness according to ISO 3.5 4.5 4.0 0.5 and less Standard Roentgenopaqueness @ co-) @ X in Extracted Tooth I I I I - - -L - I - j @: Distinct details of the root canal with the distinction higher than that of the roentgenopaqueness of enamel.
X: Extremely indistinct details of the root canal with no roentgenopaqueness.
Table 2 - Addition Polymerization Type Silicone Impression Materials B for Inspecting the Root Canal Sample Example Exampl lExample Example Comparative 4 5 6 7 Example 2 Setting Time 4.5min 4.5min 4min 5min 4.5min Roentgenopaqueness I I 4.5 3.0 4.0 3.5 0.5 and according to ISO 1 less Standard Roentgenopaqueness @ 0 @ @ X in Extracted Tooth I Distinct details of the root canal with the distinction higher than that of the roentgenopaqueness of enamel. 0: Nearly distinct details of the root canal with the distinction equal to or higher than that of the roentgenopaqueness of enamel. X: Extremely indistinct details of the root canal with no roentgenopaqueness.
Measurement of Setting Time A sample was placed in a stainless steel ring of 8.0 om in height, 24.0 mm in inner diameter, and 1.0 mm in thickness in a constant temperature room of a temperature of 23 2 'C and a humidity of 50 10 Z. A 150 gram- Vicat needle (diameter 3.0 mm) was then stuck into the sample. The setting time is expressed in terms of the length of time from the commencement of mixing to the time at which the needle could not be stuck into the sample to a depth of up to 1.0 mm and less.
4 j 1 Measurement of Roentgenopaqueness with Standard Plate Provided by ISO According to the method stipulated by 1SO 4049, standard aluminium plates of 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm and 5.0 mm in thickness and a sample plates of 1.0 mm in thickness was X- rayed to determine which of the standard aluminium plates corresponds in thickness to the sample by comparison. The roentgenopaqueness of the sample is expressed in terms of the standard aluminium plate showing the same roentgenopaque properties.
Example
The roentgenopaqueness of a sample of 1.0 mm in thickness is determined to be 2.0 mm, when it shows the same roentgenopaqueness as that of the standard aluminium plate of 2.0 ma in thickness.
The'bigberthe figure, the stronger the roentgenopaqmess is., Determination of Roentgenopaqueness in Teeth A sample was poured into the root canal of the upper central incisor tooth of an extracted tooth with the use of a syringe or lentulo, and was cured with the insertion of a bar such as a guttapercha point or file. Ten minutes after setting, the sample was roentgenized according to the method stipulated by ISO 4049 to observe the distinction of roentgenopaqueness.
@: Distinct details of the root canal with the distinction higher than that of the roentgenopaqueness of enamel.
0: Nearly distinct details of the root canal with the distinction equal to or higher than that of the roentgenopaqueness of enamel. Indistinct details of the root canal with the distinction lower than that of the roentgenopaqueness of enamel X Extremely indistinct details of the root canal with no roentgenopaqueness.
As clearly understood from the testing results given in Tables 1 and 2, the radioppaque impression materials for the inspection of the - 19- root canal, to which the radioopaque substances of the present invention are added, give more distinct roentgenograms and makes the discrimination of the root canal easier, as compared with the room temperature-setting, rubbery and elastic impression materials (Comparative Examples I and 2). Further, the impression of the details of the root canal can be taken without losing the properties of the dental rubbery and elastic impression materials.
The content is cleared of the root canal prior to operation, and therubbery impression material containing the radioppaque substance is poured thereinto by means of a spiral tool called a lentulo for setting. Thereafter, the impression material can be removed from within to consider the specific scheme or procedure for the enlargement of the root canal.
The structure of a pulp chamber and the position, configuration and number of the orifice of the root canal may be observed as well.
2. After the completion of preparation of the root canal following its treatment, the root canal can be observed as it is. if insufficient, the root canal can be re-treated for insurance purposes. 3. The preparation of the root canal can be ascertained.
Perforation, bleeding and stricture of the' root canal, a fractured root canal instrument and the positions of lateral branches of the root canal and accessory root canals may be observed and ascertained as well.
In endodontics, the insrection of the root canal has been performed relying upon intuition, experience and expertness. According to the present invention, however, such a radioopaque impression material for inspecting the root canal, which excels in roentgenopaque properties, is transported into the root canal by means of a syringe or lentulo, and a bar of suitable size such as a gutta- percha point or file is inserted into the root canal-to the vicinity of its root apex. After setting of that impression material, roentgenography can be applied to inspect the configuration, number and length of the root canal. In addition, the details of the interior Qf the root canal can be observed by pulling that impression material from within. Thus, the present invention makes it possible to perform appropriate diagnosis and treatment activities for the first time.
P J 11 11

Claims (7)

  1. Claims: -
    A radioopaque impression material for inspecting the root canal, comprising a room-temperature-setting, rubbery and elastic impression material and 20.0 to 75.0% by weight of a radioopaque substance contained therein.
  2. 2. An impression material as claimed in claim 1, wherein the roomtemperature-setting, rubbery and elastic impression material is a silicone impression material.
  3. 3. An impression material as claimed in claim 1 or 2, wherein the radioopaque substance shows a solubility of at most 0.2 g per 100 mI of water at 200C.
  4. 4. An impression material as claimed in any preceding claim, wherein the radioopaque substance is selected from powders of zinc, ytterbium, ittrium, gadolinium, zirconium, strontium, tungsten, tantalum, niobium, barium, bismuth, molybdenum and lanthanum, powers of alloys thereof, and powders of oxides, fluorides, sulfates, carbonates, tungstates and carbides thereof.
  5. 5. An impression material as claimed in any preceding claim, wherein the radioopaque substance is in the form of a finely _ 3 divided power having a mean particle size of 5 X 10 to 10 micrometers.
  6. 6. A radioopaque impression material substantially as described in any of Examples 1 to
  7. 7.
    Pub-ibh-d 1988 at Tie Patent Office, State House. 6671 High Holborn, Lonen WC1R 4TP Furtler copies may be Obtained from The Patent Office, Sales Branch. St Mary Cray, Orpington Xent BRF3 3-ILD PTIited by Multiplex techniques ltd, St Mary Cray, Kent Con. 1/87.
GB8728567A 1986-12-26 1987-12-07 Radioopaque impression materials for inspecting the root canal Expired - Fee Related GB2199839B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP61314806A JPS63165302A (en) 1986-12-26 1986-12-26 Contrasting impression material for root canal inspection

Publications (3)

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GB8728567D0 GB8728567D0 (en) 1988-01-13
GB2199839A true GB2199839A (en) 1988-07-20
GB2199839B GB2199839B (en) 1991-05-01

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Country Status (3)

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JP (1) JPS63165302A (en)
DE (1) DE3743983A1 (en)
GB (1) GB2199839B (en)

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EP0462512A1 (en) * 1990-06-18 1991-12-27 Howard G. Lee Radio opaque plastics
EP0673637A1 (en) * 1994-03-25 1995-09-27 Dentsply GmbH Dental filling composition and method
WO1996001096A2 (en) * 1994-07-04 1996-01-18 Smith & Nephew Plc Dressing
EP1806122A1 (en) * 2006-01-05 2007-07-11 Coltène AG Hardenable dental material

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US6369164B1 (en) 1993-05-26 2002-04-09 Dentsply G.M.B.H. Polymerizable compounds and compositions
US5998499A (en) 1994-03-25 1999-12-07 Dentsply G.M.B.H. Liquid crystalline (meth)acrylate compounds, composition and method
US6353061B1 (en) 1993-05-26 2002-03-05 Dentsply Gmbh α, ω-methacrylate terminated macromonomer compounds
CA2146816A1 (en) 1994-04-22 1995-10-23 Joachim E. Klee Process and composition for preparing a dental polymer product
DE19709531A1 (en) * 1997-03-10 1998-09-17 Roeko Gmbh & Co Two-component kit and gutta-percha-based post for use with the kit
DE19926728B4 (en) * 1999-06-11 2011-08-18 3M Espe Ag, 82229 Use of carrier materials and diagnostically useful additives in imaging methods for intraoral diagnostic purposes
DE10061195B4 (en) 2000-12-08 2004-12-02 3M Espe Ag Use of impression materials for the production of treatment devices
EP1502570A1 (en) * 2003-08-01 2005-02-02 Nanosolutions GmbH Radiopaque dental material with surface treated nanoparticles
US20060058867A1 (en) * 2004-09-15 2006-03-16 Thistle Robert C Elastomeric radiopaque adhesive composite and prosthesis
JP4889440B2 (en) * 2006-10-24 2012-03-07 泰生 佐藤 Rail accessory mounting device for railroad turnout

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EP0462512A1 (en) * 1990-06-18 1991-12-27 Howard G. Lee Radio opaque plastics
EP0673637A1 (en) * 1994-03-25 1995-09-27 Dentsply GmbH Dental filling composition and method
US5624976A (en) * 1994-03-25 1997-04-29 Dentsply Gmbh Dental filling composition and method
WO1996001096A2 (en) * 1994-07-04 1996-01-18 Smith & Nephew Plc Dressing
WO1996001096A3 (en) * 1994-07-04 1996-06-06 Smith & Nephew Dressing
AU699460B2 (en) * 1994-07-04 1998-12-03 Smith & Nephew Plc Dressing
EP1806122A1 (en) * 2006-01-05 2007-07-11 Coltène AG Hardenable dental material
WO2007077254A1 (en) * 2006-01-05 2007-07-12 Coltene Whaledent Ag Hardenable dental material
US7998264B2 (en) 2006-01-05 2011-08-16 Coltene Whaledent Ag Hardenable dental material

Also Published As

Publication number Publication date
DE3743983C2 (en) 1993-08-12
GB2199839B (en) 1991-05-01
JPS63165302A (en) 1988-07-08
DE3743983A1 (en) 1988-07-07
GB8728567D0 (en) 1988-01-13

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