Silver Cones Research Articles

A comparative study of five materials for use in filling root canal spaces

Five materials were tested for their suitability in filling root canals of 210 extracted permanent anterior teeth. The materials tested—Adaptic, AH-26, Cavit, Durelon, and ZOE-B&T—were placed in the canals via the endodontic pressure syringe, then subjected to methylene blue dye for intervals of 1, 7, and 30 days. Canals filled with a silver cone and laterally condensed gutta-percha and sealer and with a master gutta-percha cone and laterally condensed gutta-percha and sealer were used as controls. The teeth were longitudinally sectioned at the end of each time interval, and the marginal penetration of the dye was measured. Of the experimental materials tested, AH-26 exhibited the least marginal penetration at 30 days.

Effects of instrumentation with a chelating agent on the periapical seal of obturated root canals

The effects of a mixture of ethylenediaminetetraacetic acid (EDTA), urea peroxide, and Carbowax used in the instrumentation of root canals of extracted teeth before sealing the canals with silver cones or gutta-percha were compared with instrumentation with sodium hypochlorite alone. It was found that instrumentation of the teeth with the EDTA mixture before sealing the canals caused a twofold increase in leakage when measured by the uptake of radioactive iodine. It also was found that teeth filled with silver cones leaked 11 to 13 times more than those filled with gutta-percha. The effects of a mixture of ethylenediaminetetraacetic acid (EDTA), urea peroxide, and Carbowax used in the instrumentation of root canals of extracted teeth before sealing the canals with silver cones or gutta-percha were compared with instrumentation with sodium hypochlorite alone. It was found that instrumentation of the teeth with the EDTA mixture before sealing the canals caused a twofold increase in leakage when measured by the uptake of radioactive iodine. It also was found that teeth filled with silver cones leaked 11 to 13 times more than those filled with gutta-percha.

Corrosion of silver cones in bone: a scanning electron microscope and microprobe analysis

Sections of silver cones were implanted in tibial bone wounds in 36 Sprague-Dawley rats. Groups of six rats each were killed at monthly intervals, and the specimens were examined by scanning electron microscopy and by X-ray microanalysis. The silver cones had corroded rapidly, but they were well tolerated by the tissues. Elements of silver, chlorine, and sulfur were found in the tissues adjacent to the implants.

A comparative study of apical leakage with endodontic implant stabilizers

The apical seals of 75 extracted teeth that were treated with three methods of endodontic implant stabilizers were compared with the seals of 25 teeth filled with silver cones and 25 teeth filled with laterally condensed gutta-percha. Apical leakage was measured with the use of methylene blue dye solution. Statistical analysis showed that there were significant differences between the apical leakage obtained from the teeth treated with endodontic implant stabilizers and those teeth filled with silver cones and with laterally condensed gutta-percha.

Corrosion of endodontic silver cones in humans: a scanning electron microscope and X-ray microprobe study

Analyses with the scanning electron microscope and the X-ray microprobe were performed on 13 silver cones removed from 12 patients. The cones showed changes that ranged from surface dulling to black corrosion and pitting. Sulfur and chlorine were detected at the apical end of the cones and in the biopsy specimens of periapical tissues.

A scanning electron microscope examination of silver cones removed from endodontically treated teeth

Twenty-five silver cones were removed from teeth which had been treated endodontically from 3 months to 20 years previously. Examination by the scanning electron microscope revealed that these cones were moderately to severely corroded. The corrosion patterns were described as ranging from pitting to deep crater formation with globular or spherical agglomerations. Examinations with the electron probe showed sulfur peaks on the corroded portions of the cones. X-ray diffraction analyses indicated that the chemical compounds formed were silver sulfides, silver sulfates, silver carbonates, and silver amine sulfate amide hydrates. Tissue culture studies indicated that the corrosion products were highly cytotoxic. The mechanisms for the formation of the corrosion products have been postulated as being due to plastic deformations and metal transfer to the silver cones, plus contact of the silver with tissue fluids.

Histologic evaluation of endodontic procedures in dogs

Thirty-nine teeth of two dogs were overfilled or underfilled with silver cones or gutta-percha cones. In some teeth the furcations were perforated. In others the root canals were débrided but left unfilled and the pulp chambers were sealed only with occlusal fillings. It was shown that (1) the apical radiolucency following pulp necrosis was larger in the molar area than in the incisor area, (2) root resorption in apical lesions occurred consistently but was seen only rarely in roentgenograms, (3) root canal débridement and occlusal seal alone apparently stopped the growth of the apical lesion, (4) accidental perforations of the furcation area should be sealed off as soon as possible to reduce the incidence of periodontal destruction, and (5) underfilling of canals is usually preferable to overfilling.

The effect of dowel preparation on the apical seal of endodontically treated teeth

The effect of dowel preparation on root canals sealed with either gutta-percha, sectional silver cones, or root-end amalgam fillings has been investigated. The dowel preparations were terminated at depths of 4 and 8 mm. coronal to the apex. The prepared teeth were placed in a dye bath for 48 hours; then they were coded, sectioned, and evaluated for dye penetration along the remaining root canal filling. The results of the investigation revealed that cutting 1 mm. from a 5 mm. sectional silver cone permitted complete dye penetration in eight of nine teeth. However, no increased incidence of leakage was noted if the silver cone was not reduced in length. Root canals sealed with the lateral condensation of gutta-percha showed no adverse leakage effect due to dowel preparation. Root canals sealed by the warm gutta-percha technique presented a slightly increased incidence of leakage following dowel preparation. The root canals sealed with only a root-end amalgam permitted complete dye penetration in seven of eight teeth.

The comparative merits of silver cones and gutta percha in the treatment of fine canals of molar teeth.

The comparative merits of silver cones and gutta percha in the treatment of fine canals of molar teeth.

The chilled silver cone as a root canal filling material

In an effort to improve the existing silver cone method of filling root canals, we have presented a chilled silver cone technique that relies on the malleability of silver, on silver's contraction and expansion with temperature change, and on the elasticity of dentine. A preliminary in vitro study was conducted on forty-two freshly extracted teeth. In Phase I fitted silver cones were cooled with Freon to a possible -60° C., causing a decrease in cone diameter of at least 0.01 mm. The chilled cones were cemented into canals prepared through the apex. By measuring the distance that the cones moved beyond the apex, we determined that 0.5 mm. was the amount that could be cut off the apical tip of a fitted silver cone and still allow the chilled cone to seat to the original working distance in the sealer-coated canal. Phase II consisted of a practical demonstration of the chilled silver cone technique in conventionally prepared root canals. The silver cones were fitted, and 0.5 mm. was removed from the apical tip of the cones; they were then cooled with Freon and seated to the working distance in the sealer-lined canals. Upon warming to body temperature, the silver cones apparently expanded against the walls of the root canals, probably providing a more adequate seal without causing fracture of the teeth.

Precision apical silver cones.

International Endodontic JournalVolume 3, Issue 2 p. 22-24 Precision Apical Silver Cones J. J. MESSING, J. J. MESSING University College Hospitnl Dental School, W.C.I.Search for more papers by this author J. J. MESSING, J. J. MESSING University College Hospitnl Dental School, W.C.I.Search for more papers by this author First published: April 1969 https://doi.org/10.1111/j.1365-2591.1969.tb01251.xCitations: 6AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume3, Issue2April 1969Pages 22-24 RelatedInformation

Filling Root Canals in Three Dimensions

The ultimate objective of endodontic technique is the elimination of the root system as a source of infection and inflammation to the apical periodontium after irreversible pulp pathosis. The most desirable way to render root canals innocuous is to clean and shape them, to eliminate bacteria and tissue debris from within them, and then to obliterate them by means of a dense three-dimensional root canal filling. Accessory canals are present in practically all teeth. Many accessory canals are very small and calcify spontaneously during chronic pulp irritation, and others contain too little tissue to be clinically significant. Often, however, accessory canals are of considerable size, and, where the tissue within them becomes necrotic or infected, they may contribute to lateral root abscesses unless sealed off from the periodontal ligament. Root canal filling procedures should be directed toward the filling of significant lateral canals as well as the filling of main root canals (Fig. 8). Many techniques have been used to obturate root canals successfully. Most of these techniques employ either silver cones or gutta percha in some form. When used well, all of these techniques are valuable; when abused, no technique can succeed. The difficulty of adapting a silver cone to a less than geometrical round foramen sets certain potential limitations upon the use of silver cones in all cases. Likewise, small dimensional changes inherent in the use of gutta percha and a solvent, as well as certain problems of apical adaptation of the gutta percha when no solvent is used, encourages the evolvement of a technique by means of which gutta percha is rendered plastic without the use of solvents. Vertical condensation of warm gutta percha produces consistently dense, dimensionally stable, three-dimensional root canal fillings. Lateral canals are filled with extraordinary frequency, often with gutta percha, sometimes with cement. The final test of a root canal filling is its capacity to seal off the root canal system from the periapical tissues. The tissue compatibility of almost all commonly used root canal filling materials is very high, and for decades bone has been demonstrated to be laid down in close proximity to all of them. Overfilling, while not necessarily beneficial, will not prejudice the outcome of a case or prevent healing. Overfilling must be distinguished from overextension of underfilled cases.

Sealing properties of endodontic filling materials using radioactive polar and nonpolar isotopes

A preliminary study was conducted on the sealing properties of root canal cements, using radioactive isotopes of different particle sizes and chemical polarity. A newly modified autoradiographic technique was used to interpret leakage patterns. Under the conditions used in this study, gross leakage patterns resulted when tooth specimens were filled only with central cores of either gutta-percha or silver cones without cement. A gradient of leakage patterns was observed when eight root canal cements were tested in conjunction with central cores of silver or gutta-percha. Of the eight root canal cements tested with radio-sulfur (S 35) and tritiated glucose, only Proco-Sol and AH-26 showed no leakage. Varied results were obtained when the root canal cements were tested with tritiated proline at pH 4.8 and pH 8.2 Kloroperka N-O, Diaket, Pulpdent's PCA, and Kerr sealer exhibited leakage by the method used in this study.

Microscopic investigation of root canal diameters

Today, greater emphasis is placed on conserving teeth by means of endodontic treatm ent than was previously, and the need for research in this field has also increased. O ne of the phases of study tha t has been neglected until recently is the accurate determ ination of root canal size and taper. The minuteness and ir­ regularity of canals have caused most in­ vestigators to abandon any attem pt at actually making measurements through a microscope, although the volumes of root canals have been determined by other methods.1,2 Nevertheless, information on sizes and tapers can be of great value to the endodontist by aiding him in visual­ izing the dimensions of root canals before and during the procedures of preparing and filling them. The success of endo­ dontic treatm ent, as with any other operation, depends to a large degree on the dentist’s knowledge of the anatomy of the region involved. Furtherm ore, such da ta are needed for correlation with the sizes of files, reamers, silver cones, gutta percha cones, pluggers and broaches and may provide the m anufacturer of these instruments and materials with a basis m ore precise than trial and error for the determ ination of the necessary diameters. Scant mention of root canal sizes is made in the literature. In 1867 Latimer observed the sizes of the foramens of m andibular m olar roots, not the canals, which he said were impossible to classify on paper. In 1925, Barrett4 reported a study of 512 sectioned perm anent teeth and stated, w ithout further elucidation, th a t “the canals vary greatly in size, ranging from about 20 to 35 microns to 250 microns for the larger examples.” In 1933, M ueller5 tabulated root canal sizes under the heading, “Range in M illi­ meters of Canal Size in Gingival T h ird .” T he table provides figures for incisors, cuspids and bicuspids only, and there is no m ention of the sizes of the canals in the middle third or apical third of the roots. Meyer and Scheele6 examined root canals by making serial cross sections of the roots, the canals of which were then reproduced in wax. According to their observations, histological preparations show tha t the m ajor canal may be m oder­ ately narrow and its ramifications may