Pulpal and periapical tissue response to butyl 2-cyanoacrylate

Endodontics American

Association

of Endodontists

I. B. Bender, Ed&or

Pulpal and periapical tissue responseto butyl 2-cyanoacrylate George W. Wade, M.A., D.D.S.,* Washington, HOWARD

UNIVERSITY

COLLEGE

D. C.

OF DENTISTRY

C

yanoacrylates have been used successfully, both experimentally and clinically, for hemostasis,l repair of blood vessels,2 fixation of skin grafts, 3~4 sealing of a lung with advanced emphysema, and closure of duodenal and bronchial stumps.5 They also have been used as an oral dressing following periodontal surgery6 and as a plastic adhesive for the sealing of extraction wounds in heparinized and nonheparinized animals7 The cyanoacrylates are similar to the plastic acrylics used in dental prostheses. Although the mode of action of these tissue adhesives is not fully understood at present, it is believed that the action is produced by anionic polymerization associated with secondary intermolecular forces, such as hydrogen bonding, aided by mechanical interlocking of irregular and porous surfaces. This bonding action is catalyzed by minute amounts of water or weak bases, but excessive moisture, dilute acids, or alkali solutions may interfere with adequate bonding.8 Experimentation has shown the tissue adhesives to be good hemostatic and binding agents. However, one undesirable feature-that of increased local inflammation with necrosis-tends to limit the practicality of using the lower homologues of this material. At present, clinical studies are being conducted on the relative tissue toxicity of these products, and these studies seem to indicate that the higher homologues are less toxic. Cyanoasrylates have likewise been shown to be self-sterilizing, bacteriostatic, and bactericidal in vitro, but there is little or no antibacterial activity once the material is within the tissues.Ql lo This investigation was supported by research contract No. DA-MD-49-193-67-69241 from United States Army Medical Research and Development Command, O&e of the Surgeon General, Washington, D. C. Presented, in part, at the forty-sixth annual meeting of the International Association for Dental Research, San Francisco, Calif., March, 1968. *Professor of Oral Medicine.

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Removal of the adhesive from the tissues is accomplished by giant-cell response and phagocytosis,7 which begins at 2 to 4 weeks and is completed by 2 to 3 months.5 This series of experiments was conducted to determine the histologic effect of butyl 2-cyanoacrylate upon the dental and paradental tissues of albino rats of the Wistar strain. METHODS AND PROCEDURES Animals used were 90 days old at the beginning of the experiment. Sixty animals were equally divided into three groups. In animals of Group A, a pulpal exposure was created upon the right maxillary first molar by means of dental rongeur forceps. Butyl 2-cyanoacrylate was immediately applied over the exposed tooth with a cotton applicator. Animals of Group B, serving as controls, were similarly treated, except that no medication was applied following pulpal exposure. In animals of Group C, similarly treated, a cavity liner (varnish) was applied to the exposed pulp with a cotton applicator. All operative procedures were performed with animals under pentobarbital anesthesia, and care was taken to avoid injury to the gingival and periodontal tissues. All animals were returned to their individual cages and permitted to obtain Purina rat chow and tap water ad libitum. Animals from each group were sacrificed by chloroform inhalation at one day and at weekly intervals for 13 weeks. The maxilla was removed and immediately fixed in 10 per cent formalin. Following decalcification with 5 per cent formic acid, the tissue was sectioned at 10 microns and stained with hematoxylin and eosin for histologic examination. RESULTS Immediate hemostasis was observed in all animals of Group A (cyanoacrylate-treated) and C (cavity-varnish-treated), while pulpal hemorrhage was noted in all animals of Group B (nontreated). At one day there was no inflammatory reaction evident in the cyanoacrylatetreated specimen, even in the area of the pulp adjacent to the exposure. This was in sharp contrast to the notably acute inflammatory response about the coronal portion of the root canal in the nontreated specimen, as seen in Fig. 1. The cavity-varnish-treated specimen, at one day, showed a covering layer of varnish beneath which could be seen odontoblastic cells which appeared to be intact within each root canal, and immediately beneath the varnish a rather severe inflammatory reaction could be seen (Fig. 2). At 7’ days the acute inflammatory response of Group B had become extensive in the coronal pulpal tissue. The adjacent bone marrow spaces had become confluent, creating large spaces which were completely filled with inflammatory cells. Many multinucleated giant cells could be seen in the alveolar bone, and there appeared to be a complete disorientation of most of the principal fibers of the periodontal ligament (Fig. 3). The gingival epithelium had begun to proliferate toward areas where dentinal and cemental debris were present.

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Fig. 1. One-day nontreated sprcimen. lntcnsc inflnmnrator~ of odontoblastic cell layer about the coronal portion of root (Original magnification, x37.5.)

Pig. 2. One-day cavity-varnish-treated and shape can be seen in some portions magnification, x47.5.)

wsl~onse can be seen with loss cnual. lC, Inflammatory cells.

specimen. Odontoblastic cells (0) of normal size of the root canal. I, Interradicular bone. (Original

In the specimen of Group A few inflammatory cells were seen in the pulp, with no extension of inflammation into either the periodontal ligament space or the alveolar bone. These tissues, unlike those of Group B, remained intact. Enlargement of the pulpal blood vessels was seen, but there was evidence of a greater portion of the pulp remaining viable at this time. In one area there was viable pulpal tissue immediately adjacent to the area of exposure (Fig. 4).

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Fig.

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Fig.

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4

Fig. 3. Seven-day non-treated specimen showing apical region of mesial root. There is loss of viable pulp, disintegration of periodontal ligament fibers and marked giant-cell activity ligament space. DP, Degenerating pulp. (Original within the alveolar bone. PDL, Periodontal magnification, x250.) Fig. 4. Seven-day cyanoacrylate-treated specimen of area adjacent to coronal pulpal exposure. Note normal appearance of pulpal tissue, predentine, and odontoblasts. OC, Oral cavity. P, Pulp. P, Blood vessel. 0, Odontoblasts. DL, Dentinoid layer. (Original magnification, x1,125.)

In t.he Group C specimen, all odontoblastic cells had disappeared, inflammatory cell infiltration was quite pronounced, and there was an alteration of the interra,dicular bone with mieroabscess formation (Fig. 5). Bt 14 days no alteration was seen in the cyanoacrylate-trea.ted animals of Group A (Fig. 6), whereas in the nontreated specimen of Group B, the stage of inflammation had changed its cellular type from the acute to the chronic form. Giant-cell activity was more extensive than that seen in the ‘I-day control. Prominent reversal lines were seen in the alveolar bone, giving evidence that osteoblastic and osteoclastic activity was occurring simultaneously. This phenomenon gave rise to bone of an altered architectural pattern. In the cavity-varnished-treated specimen (Group C) , calcific degeneration of most of the pulpa. tissue had occurred; the microabscesses had become more extensive and cystic in appearance; and alteration of the interradicular bone had become more pronounced. At 21 days there was a complete absence of inflammatory cells in the cyanoacrylate-treated animals of Group A. The periodontal ligament fibers and the odontoblastic cells were intact. Remaining pulpal tissue seen adjacent to the ex-

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E ‘ig. 5. Seven-day cavity-varnish-treated of microabscess blastj ic cells I and formation x47.5.) Pulp* (Orig inal magnification,

O.S., O.M. & 0.1’. August, 1969

specimen. Note absence of all ident; sable odonto(MI in interradicular bone area. DP, Degenerating

E“ig. 6. Fourteen-day cyanoacrylate-treated specimen showing mesial root adja cent to pulpal expor we. ‘1There is enlargement of pulpal blood vessels, but no other abnormal !ity seems apparer 1t. oc, Oral cavity. D, Dentine. P, Pulp. (Original magnification, x300.)

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posed surface was orderly in arrangement and appeared viable. Pulpal blood vessels were enlarged and engorged with a brownish-stained substance believed to be hemosiderin. The Group B specimen showed beginning epithelial proliferation about each particle of dentinal fragment. There was loss of identifiable periodontal ligament fibers with granuloma formation. About the outer periphery of the granuloma, extensive giant-cell activity had occurred, giving rise to an altered architecture of the interradicular bone.

Fig.

Fig. $8

E‘ig. 7. Forty-nine-day nontreated specimen shows epithelial liming of CJrst 81ld 6 cells. R, Root. C, Cyst;. E, EP .abl.e cementum and dentine by idammatory (Orig ka 11magnification, x600.) B;.w. 8. Forty-nine-day cyanoacrylate-treated specimen showing enlargem ent aLIld ment of pulpal blood vessels. All other paradental tissues appear normal. oc, Ora PDL, PEdodontal ligament space. (Original mil.gnification, x37.5.) IlOIlVi

fack of thelil lull. ?ngol cav

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O.S., O.M. & O.P. Bugust, 1969

At 49 days the nont,rented specimen showed hppcrplasia of the surfarc epithelium, and granuloma and cyst formation could be seen about ccmental and dentinal debris. The cystic area was almost completely surrounded by epithelium of the stratified squamous type. Within the cyst, inflammatory cells of the lymphocytic variety were seen, and these appeared to be at,tacking the surface of the root fragment (Fig. 7). In the cyanoacrylate-treated specimen the predentine layer still appcarcd intact. The odontoblastic layer still showed the normal palisading, as it would appear in the normal animal. Blood vessels appeared tngorged and enlarged. with brownish staining. There was no apparent change in the architecture of the interradicular bone; however, there was less definite orientation of t.he periodontal membrane fibers with an increased widening of the periodontal ligament space, especially in the apical region, as seen in Fig. 8. After 91 days the apparent effect of the cyanoacrylate had dissipated. The cellular content of the pulp had completely disappeared, leaving a “sheathlike” stroma in the pulp chamber and the pulp canal of the mesial portion of the tooth, whereas calcific degeneration had occurred in one portion of the pulp chamber. Macrophages were seen phagocytosing the remaining cyanoacrylate. Inflammatory cells were abundantly present in the apical foraminal area estending into the periodontal ligament space. These inflammatory cells had attacked cemental and dentinal fragments, leaving eroded areas in their make. This process had extended to include the mesial portion of the second molar. Nstcnsive giant-cell activity had occurred about the periphery of the inter-

Fig. 9. Ninety-one-day cyanoacrylate-treated specimen. Note epithelial proliferation with hyperplasia about distal root fragment, loss of cellular elements from mesial root canal, and dcific degeneration of coronal pulp tissue. DP, Degenerating pulp. IC, Inflammatory cells. E, Epithelium. PDL, Periodontal ligament space. (Origin&l magnification, x37.5.)

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radicular bone. Epithelial each particle of nonviable

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proliferation and hyperplasia had taken place about dentinal debris, as shown in Fig. 9.

DISCUSSION

Our findings with respect to the hemostatic and thrombogenic properties of the tissue adhesive concur with those of other investigators.l+ Immediate hemostasis was produced, a.nd no evidence of secondary hemorrhage was observed. Histologic findings in the early stages of this experiment showed a very mild inflammatory response. This effect was noted in the pulpal tissue, periodontal ligament space, gingival epithelium, and alveolar bone. This was an unexpected finding because Awe and associates9 reported such observations in dogs. However, Vasko and Brockman5 and Woodward and colleagues,11 using a lower homologue of the cyanoacrylate, reported local inflammation followed by necrosis. We used cavity varnish in our experiment in an effort to determine whether the total effect demonstrated was produced solely by the sealing of the exposed pulp. Since complete disintegration of the pulpal tissue occurred within 14 days in the Group C animals, it would a.ppear that other phenomena, in addition to the sealing effects, were manifest. It would appear from our experiments that the tissue adhesive may have served as an oral dressing, thus protecting the underlying pulpal tissue. It would also seem that the higher homologues and/or a thinner application of the tissue adhesive has less toxicity upon the dental and paradental tissues. Thus, our findings in this regard concur with those of Vasko and Brockman” and others.F, 7, I3 Giant-cell activity, inflammatory response, and alteration of the periodontal membrane were manifest in the nontreated animals, but in the cyanoacrylatctreated animals each of these activities was very subdued or did not occur. It would thus appear that the cyanoacrylate might have an ameliorative effect. In each instance in which the tissue adhesive was applied to pulpal tissue we found that, although there was a response of varying degrees, the pulp remained viable and the odontoblastic layer remained intact throughout most of this experiment. Contrasted to the findings in the nontreated animals, granuloma and cyst formation was much delayed and did not occur until the ninety-first day, Perhaps this may have been due to loss of the sealing effect of the tissue adhesive after this period of time. No tissue adhesive could be demonstrated physically during the latter stages of this experiment. We believe this was probably due to the method of application and the thinness of the medication applied. The effect of the presence of the drug, however, persist,ed throughout 70 days of the experiment, showing that the effect of the drug persists for at least 70 days when applied to the exposed pulp of the albino rat. Although additional research on these tissue adhesives is needed, it would appear that this material might have clinical application in the treatment of pulpal exposures.

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SUMMARY A series of experiments was conducted with the use of butyl 2cyanoacrylate and cavity varnish on traumatically exposed pulps in the albino rat. Histologic comparisons were made between three groups of animals, showing that t.he sealing effect of the cavity varnish was dissipated in between 1 and 7 days. Cyanoacrylate produced immediate hemostasis and a delay in the inflammatory response. Granuloma and cyst formation occurred in the nontreated animals at 21 and 49 days, respectively, but a similar effect was not seen in the cyanoacrylatetreated specimen until the ninety-first day. Marked giant-cell reaction was observed in the nontreated and cavity-varnish-treated animals as early as 7 days but was not seen in the cyanoacrylate-treated group before 91 days; nor was there a change in the appearance of the periodontal ligament space or the interradicular bone of the latter group until the ninety-first day. Inflammatory response was seen in the nontreated group as early as the first day. Enlargement of the pulpal blood vessels was seen in the cyanoacrylate-treated animals and, although a disturbance of the orderly palisade arrangement of the odontoblasts was noted, these cells remained viable at the end of 70 da.ys and did not completely loose their viability until the ninety-first day. These experiments show that butyl 2-cyanoacrylate may have an ameliorative effect upon exposed pulpal tissue in the albino rat for 90 days. Grateful appreciation M. Taylor, who assisted photography, respectively.

is offered Dr. D. Peagler, in the slide interpretations,

Mrs. K. Bunnag, histopathologic

Mr. A. Briggs, and Mr. slide preparations, and

REFERENCES

N. S., and Awe, W. C.: Control of Hemorrhage From the Heart and Aorta, 1. Braunwald, Utilizing a Plastic Adhesive, Surgery 51: 786, 1962. a New Plastic 2. Ota, K., Nor-i, S., Koika, T., and Inow, T.: Blood Vessel Repair Utilizing Adhesive, J. Surg. 5: 453, 1965. of Split-Thickness Skin 3. Jesse, R., Anderson, H. B., and Healey, J. E., Jr.: Fixation Grafts With Adhesive, Plast. & Reconstruct. Surg. 33: 272! 1964. 4. Fichl, R. A.: An Adhesive for the Primary Closure of Skin Incisions, Plast. & Reconstruct. Surg. 30: 607, 1962. 5. Vasko? J. S., and Brockman, S. K.: Clinical and Experimental Experiences with Plastic Adhesives, Ann. Surg. 162: 123, 1965. P. M., and Leonard, F.: Application of a New 6. Bhaskar, 8. N., Friseh, J., Margetis, Chemical Adhesive in Periodontal and Oral Suraerv. D *I ORAL Sm.. ORAL MED. & ORAI, PATH. 22: 526-535, 1966. 7. King, D. R.. Revnolds, D. C., and Kruger. G. 0.: A Plastic Adhesive for Non-suture Seal&r of Extra&ion Wounds in Heuarinyzed Dogs. I ” I ORAL SURG.. ORAL MED. & OVAL PATH. 24: 307 1967. J. O., Del Aguila, R. P:, and Yeager, .G. H.: Experimental Control of Renal 8. Just-Vi&a, Hemorrhage With the Use of Rapidly Polymerrzmg Adhesives, Surgery 65: 531, 1964. N. S.: Rapidly Polymerizing Adhesives as a 9. Awe, W. C., Roberts, W., and Braunwald, Hemostatic Agent: Study of Tissue Responses and Bacteriological Properties, Surgery 54: 322. .l Sf%.?. 10. Eaplan, G., and Borchardt, K. A.: The Antibacterial Properties of Methyl 2-Cyanoacrylate in Non-suture Closure of Experimentally Infected Wounds: Preliminary Report, Plast. & Reconstruct. Surp. 38: 567. 1966. 11. Woodward, S. C.~Herrman~ J. B., Cameron, J. L., Brandes, G., Pulaski, E. J., and Leonard, F.: Histotoxicity of Cyanoacrylate Tissue Adhesive in the Rat, Ann. Surg. 162: 113, 1965. 12. Shafer, W. G., Hine, M. K., and Levy, B. M.: A Textbook of Oral Pathology, Philadelphia, 1964. W. B. Saunders Comoanv. chau. 11. DD. 487-505. 13. Bhaskar, S. N., Frisch, J.; C&-igh~, D. ‘I?.; and Margetis, P. : Effect of Butyl Cyanoacrylate on the Healing of Extraction Wounds, ORAL Sums., ORAL MED. & OVAL PATH. 24: 604-616, 1967. ---7

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