Pulpless Teeth Research Articles

Histological Study of the Periapical Tissues of Incompletely Formed Pulpless Teeth Filled with Zinc Preparations and with Magnesium Hydroxide

The effect of various zinc preparations and magnesium hydroxide on the apical tissues of incompletely formed premolars in dogs was studied histologically. Favorable results were obtained in 13 of 19 instances where zinc oxide and eugenol were used. Zinc oxide with water or zinc sulfate solution and magnesium hydroxide with water produced unsatisfactory results.

Regeneration of the attachment apparatus on pulpless teeth denuded of cementum in the rhesus monkey.

Regeneration of the attachment apparatus on pulpless teeth denuded of cementum in the rhesus monkey.

Induction of apical formation in immature teeth by different endodontic methods of treatment

summaryAn experimental study is described of the apex formation and structure in immature permanent teeth after vital amputation, vital extirpation and after the treatment of teeth with necrotic pulp. Experiments in young dogs suggest that after vital amputation of the coronal part of the pulp, root formation was continued through the process of changed odontogenesis. In cases where the pulp had been completely extirpated or after the treatment of pulpless teeth, the process of normal odontogenesis was interrupted and the apex was completely closed by non‐homogeneous vital calcified tissue. On the basis of studies of the structure of this calcified tissue, it was concluded that it was a product of the formative activity of cells originating from the successive differentiation of fibroblasts in the young granulation tissue. The experiments suggest that following vital amputation of the pulp in children, further root odontogenesis is possible. In the treatment of pulpless teeth, the basic target should be stimulation and preservation of the formative activity of the granulation tissue cells in the apical part of the root canal to allow the possibility of calcified callus forming in the wide apical opening.

A modification of the acid-etching technique for restoring fractured incisors

A modification of the acid-etching method for the restoration of a fractured pulpless tooth is described.

A microbiologic evaluation of endodontic instrumentation in pulpless teeth

Thirty-three patients with infected root canals were selected for endodontic therapy, and the canals were enlarged under aseptic conditions without the use of an irrigant. Of the cultures of dentin substance removed, 21.4 per cent were negative, and few viable bacteria were detectable during the later stages of canal enlargements. More culturable bacteria were obtained on absorbent points than from dentin removed on reamers. Sodium hypochlorite was found to be an effective germicidal irrigant after canal enlargement, producing “sterile” canals in nearly 75 per cent of the teeth. However, 53.3 per cent of the supposedly “sterile” canals produced positive cultures at the next appointment. More than one fourth of the 504 cultures in this study were negative after 48 hours but became positive after 5 days.

Electrophoretic differentiation of radicular cysts and granulomas

Polyacrylamide-gel electrophoresis was used for differential diagnosis of radicular cysts and granulomas. Root canal fluids were aspirated from forty anterior teeth with radiographic evidence of periapical pathosis, and from one pulpless anterior tooth with no radiographic evidence of periapical pathosis. Endodontic therapy was performed on all the teeth, and all the periapical lesions were surgically removed. The lesions were examined histologically, and the histopathologic diagnoses were then compared with the electrophoretic patterns. Analysis of the root canal fluids showed the following: (1) An albumin pattern was found in all thirty-one of the cases diagnosed histologically as being granulomas. The same pattern was also found in the case of the pulpless tooth without an area of rarefaction. (2) In eight of the nine cases diagnosed histologically as cysts, there was a much more intense albumin pattern and other patterns in the globulin regions. In the one case of a cyst that was misdiagnosed, the apical portion of the canal was calcified and the cyst lumen was never penetrated.

Immediate restoration of pulpless teeth

A technique for the fabrication of immediate composite-resin cores retained by Para-post and/or T.M.S. pin(s) has been described. It affords the following advantages: (1) It is timesaving; (2) it is economical; (3) it provides substance for an immediate tooth preparation where little or no coronal tooth structure remains; (4) it simplifies the making of temporary crowns by providing a retentive tooth preparation; (5) it provides the opportunity for making the impression for the permanent crown at the same time the resin is inserted, if the marginal gingiva is healthy; (6) it assures good marginal adaptation of the core to the adjacent tooth surfaces; (7) the nonparallelism of the post(s) and pin(s) enhances the retention of the core.

Determination of the moisture content of vital and pulpless teeth

Restorative dentists have the clinical impression that endodontically treated teeth are more friable and fracture more easily. The object of this study was to determine the water content of pulpless teeth as one of the possible factors contributing toward tooth brittleness. Extirpation of pulps from dog teeth was followed by extraction of the teeth after predetermined time intervals so that the value for the water content could be plotted against time. The total water content of each tooth was divided into the free water and bound water. The free water was determined gravimetrically. The bound water was tested by a Differential Thermal Analysis, which graphically reproduced the total moisture content of the calcified tissues. There was 9 per cent less moisture in the calcified tissues of pulpless teeth than in those of vital teeth.

Study on the sensitivity of some culture media inoculated by a minimum number of newly isolated bacteria from pulpless teeth.

Study on the sensitivity of some culture media inoculated by a minimum number of newly isolated bacteria from pulpless teeth.

Induced apical closure of immature pulpless teeth in monkeys

The results of a radiographic and histologic study of twenty-seven monkey teeth indicate that periapical healing and the formation of calcified tissue at the root ends of pulpless, infected, immature teeth can occur after either of two treatments: filling of the canal with a paste dressing or use of an induced blood clot. The best chance for success with inducing apical closure is in those cases in which the pulpal and periapical pathosis has not been present very long. If pulpal necrosis is not complete, a more normal type of root continuation can be expected. When complete necrosis and extensive periapical destruction are present, the chances of successful results are lessened, particularly if a negative culture cannot be obtained.

The tapered dowel pin as a post and core

A one-sitting direct method for installing an adequate post which will prevent accidental coronal fracture of jacket-prepared pulpless teeth has been described. Emergency adaption to fit an existing crown has also been suggested.

The Role of Endodontics in Restorative Dentistry

A variety of designs may be utilized when restoring the pulpless tooth to health and function. It is essential to remember that endodontic therapy alone is not the final effort in the preservation of the involved tooth. Careful consideration must be given at the time of diagnosis to the restorative and periodontal techniques which may be required to restore and protect the pulpally involved tooth.

Stimulation of root formation in incompletely developed pulpless teeth

A series of twenty-one incompletely developed pulpless human teeth have been treated conservatively with calcium hydroxide and methylcellulose as a root-filling material. Observation times varied from 14 to 75 months. Elimination of bacteria was achieved by routine endodontic procedures in conjunction with irrigation and dressing with an aqueous solution of 0.03 per cent chlorhexidine and 0.3 per cent cetrimide. Of the twenty-one cases, fourteen showed complete, five partial, and two no root development during the period of observation. Periapical repair was complete in twenty of the twenty-one cases and is proceeding satisfactorily in the remaining case. A clinical evaluation of success showed nineteen cases to be successful and two doubtful, with no failures over the period of observation. Histologic material has been presented which revealed that new tissue had been formed, both apically and within the old canal. This consisted of pulp, interglobular dentine, cementum, and attached periodontal membrane fibers. Two calcified layers of interglobular dentine extended into the old canal and lined it. However, no calcific barrier was present at the coronal extremity of the canal. Thick deposits of cellular and acellular cementum not only covered the newly formed tissue but extended beyond the junction with the old root. The results of the clinical series and the histologic material support the conservative approach to the treatment of pulpless, incompletely developed teeth. The method is indicated because of its simplicity, the lack of surgical trauma, and the improved prognosis afforded by the further root development.

Construction of posts for teeth with existing restorations

Two techniques for construction of posts for pulpless teeth to fit existing restorations have been described. In one technique, part of a paper clip is used as a core to develop the wax pattern for a gold post. In the other, a piece of acrylic resin forms the core for a resin pattern which is subsequently cast in gold. In both instances, the post is adapted to fit an existing crown.

The incidence and identity of microorganisms present in root canals at filling following culture reversals

0 ne of the objectives of root canal therapy is to eliminate microorganisms from the root canal system and the periapical tissues of pulpless teeth prior to filling.1 The bacteriologic examination originally described by Onderdonk2 to test for these microorganisms has undergone many modifications over the years. Today the “culture” meCod is the most practical bacteriologic examination and is the only way to check for the elimination of organisms.3 Some endodontists41 ’ require only one report of a sterile root canal culture before filling the canal, while others61 7 require tu.0 consecutive negative reports. In either case, cultures and smears obtained immediately before the filling of root canals often reveal the presence of organisms, even though the cultures obtained at the previous appointments were negative.8, l1 This incidence of culture reversal seemed to vary greatly.*-I1 Some studies, however, used only one negative culture before filling, others used two, and some studies varied the sampling technique itself. Persisting infection was reported by Engstrijm and colleagues lo to reduce the success of treatment. Of the

Construction of Detached Core Crowns for Pulpless Teeth in Only Two Sittings

By use of the technic described, a single crown or a fixed partial denture can be fabricated easily and with satisfactory results.

Calcific metamorphosis of the pulp: Its incidence and treatment

Periapical roentgenograms of 881 patients were examined and calcific metamorphosis of the pulp was diagnosed in forty-one teeth of thirty-four patients, an incidence of 3.86 per cent. These teeth were examined clinically and roentgenographically 4 years later for evidence of continuing calcification and periapical pathologic change. Only three teeth had developed periapical lesions, and in two of these cases the lesion was between the tooth exhibiting calcific metamorphosis and an adjacent pulpless tooth. An analysis of the data led to the following conclusions: 1. 1. There appears to be a significant correlation between calcific metamorphosis and a history of trauma, particularly if there is a history of tooth mobility as a result of the trauma. 2. 2. Teeth exhibiting calcific metamorphosis usually respond to the vitalometer, but generally more electric current is required. 3. 3. Not all such teeth become discolored; furthermore, there seems to be no correlation between the amount of discoloration and the degree of calcific metamorphosis. There also seems to be no correlation between the amount of discoloration and the response to the vitalometer. 4. 4. Calcific metamorphosis may be a pathologic deviation from the normal pulp, but during the first few years after trauma an accompanying periapical rarefaction on the roentgenogram is rare. 5. 5. The only definite criterion for endodontic or surgical intervention in calcific metamorphosis appears to be the appearance of periapical rarefaction on the roentgenogram.

The Restoration of Pulpless Teeth

A number of methods for restoring pulpless teeth have been described. Emphasis has been placed on the factors which govern the selection of the method to use. The clinical procedures for each have been described in detail.

Single unit cast post crown for pulpless anterior tooth roots

The post and crown for pulpless teeth can be cast as one unit by constructing a pattern with cold-curing acrylic resin and wax. The crown part of the restoration is made with a recess for a labial veneer of acrylic resin. Cementation can be accomplished on the second visit. A single unit cast post and crown saves valuable chair time and simplifies an operation without sacrificing accuracy or esthetic requirements.

Stabilizing mandibular dentures

A technique for stabilizing removable dentures involves the use of endodontically treated pulpless teeth that are connected by a Doldar bar. This device provides support and retention for the denture and provides broken stress for both rotational and vertical stress. The Doldar bar technique and the attachments are successful and versatile in removable partial denture construction. Several patient situations are described to illustrate the use of the Doldar bar in complete and removable partial dentures.