Healing Potential in Periodontal Lesions

most common bony deformity associated with peri­ odontal disease was the interdental crater. It repre­ sented 35.2% of 176 lesions recorded and 6 2 % of all osseous defects seen in the mandible . What constitutes the norm in describing the marginal aspects of the alveolar processes is a subject which should be discussed with more objectivity. The socalled "ideal alveolar process" as described on skull material of Ochsenbein and shown often by others is a concept that exists in theory o n l y . The normal alveolar process has tremendous variability and rarely presents the classical picture of thin margins at the tooth interface, parabolic scalloping and proximity to the cemento-enamel junction. Once more, interdental septae are rarely convex at their crests, but more often flat or depressed at their most coronal height. B u l ­ bous marginal bony contours are commonly encoun­ tered, particularly in the posterior maxilla, not to mention the numerous exostoses that are seen adjoin­ ing the marginal bone in other parts of the jaw. These genetic variations are more than chance occurrences. On the contrary, one rarely sees dried human skull material meeting the requirements that we have estab­ lished as the norm. 8

The Interdental Crater by BERNARD S. MOSKOW, D.D.S.,

9 , 1 0

M.SC.D.* IT HAS BEEN A universally consistent observation that inflammatory periodontal lesions start in the interden­ tal area; thus the earliest osseous changes associated with periodontitis are likely to be interproximal and are morphologically described as interdental craters. Such osseous craters are a reflection of the col-like topography of the normal interproximal gingiva and the more modified flat or concave shape of the bony scaffolding beneath the gingiva. Prior to the descrip­ tions of C o h e n , the interdental gingiva was thought to be pyramidal in shape (a papilla); however, several investigations have now corroborated the later descrip­ tions of the interproximal zone as being a concave ridge or " c o l " (a term borrowed from moun­ taineering, in which it is used to describe a ridge-shaped depression between two adjacent peaks ). It is now understood that the shape, including the width and the depth of the col, is intimately related to the buccolingual dimension of the approximating teeth and the contour of the contacting relationship of these teeth. Further, it has been pointed out that the shape of the alveolar crest is invariably a reflection of the relation­ ship of the marginal ridge height of adjacent teeth and/or the axial position of the roots of adjacent teeth. If, for example, the proximal surface of adjoin­ ing teeth are relatively flat, the roots of these teeth are apt to be very close to each other and the interdental osseous septa will be very thin. This is often the case in the mandibular incisor region where little or no cancellous bone intervenes between the alveolar bone proper of adjacent teeth. In this region, the faciallingual width of the bony interdental septum is meager, and thus early resorptive lesions of the crest of the alveolus are not likely to produce crater-like bony defects. O n the other hand, early interdental inflam­ matory lesions in the bicuspid and molar regions com­ monly result in bony craters of variable depth and morphology. Similarly, interdental intraosseous defects occur with much more frequency in the posterior zones than in the anterior portion of the mouth, and this is largely a reflection of the normal bulk of the interprox­ imal bone. Manson, in a study of bone morphology and bone loss in thirty patients, observed that the 1

11

2 , 3

Changes in the crestal and marginal morphology of the alveolus occur as the inflammatory process spreads to the underlying periodontium. Often these resorptive changes in the bone are uniform and do not produce gross changes in the contour of the marginal part of the alveolar process. If the gingivae recede along with the bone, periodontal pocket depth can be minimal or nonexistent. Interdental cratering, irregular margins, intraosseous defects, hemiseptae and apposition of buttressing bone as a result of a progressive inflamma­ tory lesion can produce an unlimited variety of osseous defects in the periodontium. The question of how to manage such bone deformities has been the source of endless commentary and a great number of publica­ tions.

1 , 4 , 5

6

7

The concept of pocket elimination in the treatment of periodontal disease is a tried and tested approach to the control of the problem. Curettage, as well as various surgical approaches, have been utilized, all with so-called documented clinical success. The idea of creating favorable or "physiologic" contours along with pocket elimination is also commonly accepted as an objective of periodontal treatment. Differences of opinion, however, continue to exist as to "how far" one should go in attempting to create osseous contours which reflect the text book ideal. The removal of bone as an objective of pocket elimination in certain types of periodontal defects also has been questioned, and this remains a subjective or personal judgement in therapy. One frequently used approach to the management of osseous craters is the surgical removal of one peak of crater, thus creating a pryamid-like contour to the interproximal alveolus. T o what extent nature further

* Columbia University, School of Dental and Oral Surgery, 630 W. 168th St., New York, NY 10032. 754

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remodels the contour of such surgically treated bone is unknown; however, those practitioners striving for minimal immediate postoperative interproximal pocket depth usually are compelled to use this approach. Certainly, any attempt to recontour any portion of the alveolar process requires exposure of the area involved and a fairly substantial surgical procedure. It has been my experience that curettage and debridement of inter­ dental craters without osseous contouring often results in favorable changes in the crestal alveolus. Curettage in this instance includes removal of the epithelium covering the crater, the underlying inflammatory ele­ ments and the transseptal group of connective tissue fibers, thus exposing the bony defect. This has been accomplished by means of either the gingivectomy or flap approach. C A S E REPORTS

Case I. A 46-year old female patient presented gingi­ val hyperplasia, pocketing and crater-like osseous de­ fects, particularly in the lower left lateral-cuspid and lower left cuspid-first premolar areas (Fig. 1). This is a commonly encountered problem, particularly where periodontitis occurs where there is crowding and overlapping of the anterior dentition. Four months following pocket elimination via gingivectomy, gingival contours in this area were bulbous and thick, giving a ledge-like appearance to the marginal gingiva (Fig. 2). Three years postoperatively, gingival contours ap­ peared more favorable, with absence of periodontal pockets (Fig. 3). The radiographic picture indicates healing and remodeling of the intersseptal alveolus despite lack of osseous contouring in the initial ap­ proach to treatment (Figs. 4 and 5). This clinical result has been maintained for a period of 9½ years. Case II. Extensive destruction of interdental septum between lower right lateral and cuspid with a deep osseous crater at the level of the apical one-third of the adjoining teeth (Fig. 8) was seen. This advanced perio-

755

FIGURE 2. Four months after surgical pocket elimination (gingivectomy) resultant gingival contours are bulbous and thick (see arrows). No attempt was made to eliminate the osseous craters by osteoplasty.

FIGURE 3. Three years after periodontal therapy, the interden­ tal areas display more favorable contours as a result of natural change in the underlying osseous form (see arrow). Some papillary hyperplasia persists in the lower left cuspid and first premolar area.

FIGURE 4. Preoperative radiogr iphs reveal classical picture of interdental osseous crater in the lower left lateral incisor and cuspid region (see arrows).

dontal lesion was associated with a chronic fistula of un­ known etiology in a 15-year-old boy who was in the pro­ FIGURE 1. Pre-operative photograph of 46-year-old female cess of completing orthodontic therapy (Fig. 6). There patient with generalized, moderately advanced periodontitis. Interdental craters were particularly noticeable in the lower was extensive gingival hyperplasia and fibrosis, appar­ ently resulting from an untreated puberty gingivitis and left lateral incisor and cuspid and lower left cuspid and first premolar areas (see arrows). the persistent local irritation of orthodontic bands and

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apy consisted of simple curettage and debridement of the affected area to the level of the existing osseous interdental crater. Exposure of the surgical site was ac­ complished by means of a small labial and lingual flap and revealed extensive denudation and exposure of the proximal root surfaces as noted on the preoperative ra­ diograph (Fig. 8). Treatment of the more generalized gingival problem was done via gingivectomy and gingivoplasty (Fig. 7). Dramatic healing and reconstitution of a major segment of the lost intersseptal periodontium is ready discernible on the postoperative radiograph, exposed 11 months following treatment (Fig. 9). The patient was followed for 5 years after periodontal FIGURE 5. Postoperative radiograph taken 3 years after treat­ therapy and continued to maintain good periodontal ment indicates apparent change in intersseptal bone (see ar­ health. rows). Note that the x-rays were exposed at the same angle as Case III. One of many deep periodontal lesions in a the preoperative films. 38-year-old male patient with advanced periodontitis and secondary occlusal traumatism may be seen.

FIGURE 6. Extensive gingival hyperplasia present in 15-yearold-boy in the process of completing orthodontic therapy. Arrows indicate site of chronicfistulaand extensive periodon­ tal breakdown of unknown etiology (see radiographs—Fig. 8).

FIGURE 8. Pretreatment radiograph demonstrating extensive destruction of interdental septa and resultant deep interdental crater. Arrow indicates external resorptive lesion on root surface near the cemento-enamel junction.

FIGURE 7. Clinical photograph taken shortly following surgi­ cal periodontal treatment. The lower right lateral incisorcuspid area was treated by openflapand debridement, includ­ ing planing of the root surfaces.

accumulation of plaque. There was no evidence of alveo­ lar destruction except in the area shown. A shallow, ex­ ternal, resorptive lesion was seen on the root surface of the mesial surface of the lower right lateral incisor, just beneath the cementoenamel junction. Periodontal ther­

FIGURE 9. Apparent regeneration of affected area of attach­ ment apparatus 11 months following treatment.

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Case V. Note the insidious, chronic inflammatory le­ sion in female patient 44 years of age, associated with gingival hyperplasia, edema and generalized pocketing. Mandibular anterior segment revealed generalized marginal alveolar resorption with more extensive crater-like lesions in the upper central incisor and upper lateral-cuspid areas (Fig. 14). Pocket elimination by means of the gingivectomy approach and curettage of the osseous lesions induced favorable changes in the marginal alveolar contours within 30 months following therapy (Fig. 15). This patient has been followed for 11 years, and there is no evidence of regression. DISCUSSION

The cases demonstrated above are presented as documentation of a direct and simple method of treat­ ing interdental craters without osseous surgery. The examples depicted in this report are only a few of the very many similar cases that the author has observed following routine treatment of the interdental crater. They are reported herein with the full understanding of the limitations of the roentgenogram in assessing

FIGURE 10. Preoperative roentgenogram of 38-year-old male. Note extensive interdental destruction in the upper left centrallateral incisor and upper left lateral-bicupsid regions with deep interdental crater formation.

Thinning and extensive marginal resorption of the in­ terdental alveolus can be seen in the upper left cen­ tral-lateral incisor and upper left lateral-cuspid areas (Fig. 10). Exposure of the affected area via flap and thorough debridement produced favorable postopera­ tive healing with possible reconstitution of the previ­ ously resorbed interdental septum in the upper left cen­ tral-lateral incisor area 28 months postoperatively (Fig. 11). Patient discontinued periodontal maintenance 4 years after original therapy. Case IV. Classical picture of progressive marginal periodontitis with uniform interdental crater formation is seen in a 36-year-old female patient. The lesions were associated with gingival hyperplasia, pocketing, open contacts and overhanging interproximal restora­ tions (Fig. 12). Healing and remodeling of the areas seen are noted on the 33-month postoperative radio­ graphs (Fig. 13). The deficient contacts and overhang­ ing restorations continue to remain despite attempt at treatment by the restorative dentist. Patient has been followed for 5 years since original therapy with contin­ ued maintenance of periodontal health.

FIGURE 11. Twenty-eight months after treatment x-ray indi­ cates extensive repair in previously affected areas. Therapy consisted of a full thickness flap and curettage and debridement of surgical site.

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simply for photographic purposes, in the author's mind, exceeds the bounds of ethical practice. The analyses and criticisms made by both Prichard and Friedman regarding x-rays as a means of recording "reattach­ ment" or regeneration in some ways are correct and indeed are interesting. The rendering of a threedimensional structure (the tooth) within the jaw (also three-dimensional) on a film, which is a composite picture in one dimension, is frought with possibilities of error in interpretation. Their major point in negating the usefulness of postoperative radiographs is that "increased density of bone after successful periodontal therapy often gives the appearance of coronal growth of b o n e . . . . The reduction of enlarged marrow spaces by deposition of new trabeculae increases its radio opacity and thus bone is recorded on the film made after treatment." Friedman has taken great effort to stress that the progress of the inflammation into the FIGURE 12. Before treatment x-ray of 36-year-old female patient with generalized and advanced marginal periodontitis. underlying alveolus results in wide open marrow spaces Deep interdental osseous craters can be noted in area shown. and thinning of the scaffolding of the alveolar process. 12,14

12

Arrows indicate open contacts and overhanging margins on restorations.

FIGURE 13. Thirty-three-month post-treatment radiograph in­ dicates favorable changes in crestal osseous profile despite continued absence of optimal dental care. Arrows show over­ hanging margins on fillings. 12

the results of periodontal therapy. Since Friedman and P r i c h a r d presented their carefully prepared papers on the shortcomings of the radiograph in the evaluation of postoperative results, considerable ques­ tion has been projected upon the use of the x-ray in the documentation of clinical results in periodontal therapy. This has resulted in the common employment of surgical "reentry" in order to document by photog­ raphy the effects of treatment. Both radiology and photography offer unlimited bounds for image distor­ tion and deceivement, either accidental or deliberate; but to routinely subject patients to additional surgery 13,14

FIGURE 14. Deep crater-like bony lesions seen in lower left and right central incisor and lower left central-cuspid area of 44-year-old female patient with generalized and advanced marginal periodontitis. The gingivae were hyperplastic, edem­ atous and retractable.

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reorganization and remodeling of the internal struc­ tures of its alveolar support. In general, however, histologic views of the marginal aspect of an alveolar process undergoing inflammatory change reveal smaller marrow spaces and a more internally dense bone (Figs. 16 and 17). A s the disease becomes more progressive, this compensatory laying down of new bone, along with the simultaneous resorptive phenom­ enon, reaches greater proportions, and the result is the endless variety of bizarre bony lesions encountered in the more advanced cases of periodontitis. Buttress­ ing bone or the so-called "lipping effect" are clear examples of this phenomenon. Depending on the extent and nature of the inflammatory lesion, the marginal aspect of the alveolar process is often irregu­ lar or ragged on its surface but is likely to be denser in 15

FIGURE 1 5 . Post-treatment radiograph exposed 30 months after periodontal therapy indicates favorable changes in crestal morphology with possible increased height of alveolar crest.

This, he explains, accounts for the increased radiolucency seen on radiographs. Microscopic study of the effects of the inflammatory reaction upon the periodontium in human autopsy and surgical specimens does not support this thesis. The marginal aspect of the periodontium is the first line of defense in the attachment apparatus to the advancing inflammatory infiltrate. Even prior to surface resorp­ tion of the alveolar crest, inflammatory cells are seen within the marrow spaces, and fibrosis of the most superior marrow cavities is a common phenomenon. Endosteal apposition of new bone is a routine obser­ vation sometimes long before osteoclastic resorption of crestal bone is discernible. Reinforcement of the crestal area by the apposition of new bone on the proximal, facial and lingual, and internal aspects of the alveolus is a routine response to the first signs of crestal resorption. The normal internal structure of any interdental septa also varies tremendously and no doubt initially affects the size of the marrow spaces. It has been shown repeatedly that one manifestation of the effects of function upon the periodontium is the 12

FIGURE 16. Classical histopathologic picture of marginal periodontitis. Mesiodistal section through crater depicting pocket formation, calculus adhering to tooth surface and inflammatory cell infiltration of the gingival corium. The transseptal fiber group remains intact, and there is fibrosis of the most superior marrow spaces. Note reinforcement and thickening of the crestal alveolus as a result of endosteal and surface bone apposition. D = Dentin, C = Acellular cementum, Pdl = Periodontal ligament, A M = Fatty marrow, F M = Fibrosis of marrow spaces, A C = Alveolar crest, MI = Marginal inflammatory infiltrate, Ca = Calculus. (H & E, original magnification, x 35.)

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While unintentional distortion resulting from tech­ nique can be a factor in evaluating pre- and postopera­ tive radiographs, it is my contention that the value of properly taken, exposed and developed radiographs to an experienced observer of periodontal lesions has unlimited value. The accuracy and duplicability of xrays taken with a parallel projection have been stressed by U p d e g r a v e and Prichard. Radiographs exposed at higher kilovoltage (i.e. 75 kvp or higher) give highly diagnostic representations of bone and teeth, although 16,17

FIGURE 18. Mesiodistal section through dried specimen, mandibular bicuspid region affected by marginal periodontitis. A typical interproximal crater ( C ) can be noted. Section is not FIGURE 17. Microscopic section showing typical crater-like directly through center of specimen but closer to lingual lesion in marginal periodontitis. An intense band of inflam­ surface. Note increased thickening and density of the bone in matory cells is present in the subsulcular zone and can be seen the area of the alveolar crest. infiltrating through the transseptal fiber apparatus into the alveolar crest. All of the marrow spaces seen in this field demonstrate fibrosis. Buttressing of the crestal area has oc­ curred as a result of new endosteal bone formation and appositional changes on the mesial and distal surfaces. D = Dentin, C = Acellular cementum, Pdl = Periodontal ligament, F M = Fibrosis of marrow spaces, A C = Alveolar crest, M I = Marginal inflammatory infiltrate. (H & E, original magni­ fication, x 55.)

its internal structure. If serial facial-lingual microscopic sections are made of an interdental inflammatory le­ sion, the osseous scaffolding near the crest will be seen to be extremely dense on sections closer to the facial or lingual cortical plates (Figs. 18 and 19). Histologic specimens taken directly through the center of the crater are apt to be much less dense, sometimes revealing an open marrow cavity with accumulation of inflammatory cells (Fig. 20). This represents the chan­ nel through which the major vascular distribution to the periodontium travels and through which the inflam­ matory infiltrate passes into the deeper structures. Frequently, however, the most concave portion of an osseous crater is also seen histologically as a thick, cortical-like wall of bone. A s mentioned above, this is a reflection of the reparative effects of the host to the chronic and insidious inflammatory reaction and an attempt to confine and limit the progress of the disease.

FIGURE 19. Radiographic picture of dried specimen in Figure 18. The increased density of the crestal alveolar bone ( C ) is not discernible on the x-ray.

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as a thickened lamina dura after successful periodontal therapy have been reported as resulting from increased apposition of cortical bone and a decrease in the size of the marrow spaces. In light of the histopathologic changes described above, this explanation is hardly satisfactory as such changes are often provoked by the progress of the disease itself (Figs. 16 and 17). The evidence presented here supports the more logical explanation that the radiographic picture of a healed crater represents some resorptive changes at the peaks of the crater and a "filling i n " at the base of the crater (see F i g . 21). While definitive experimental evidence is lacking, it is our impression that coronal apposition of some new support including crestal bone, periodon­ tal ligament fibers, and cemental apposition to a small degree also can be anticipated in the case of craters. In case II extensive reconstitution of a previously deep crater is demonstrated. These observations are based not only on duplicatable x-ray examination but also by careful probing and clinical examination. Once more, these findings are not chance occurrences but have been observed frequently and reported occasionally in the l i t e r a t u r e . The concept that alveolar bone must be physically altered in order to change its topography is erroneous and has been challenged by the work of Glickman and P a t u r . Simple instru­ mentation of the tooth surface by removal of calculus can induce resolution of gingival inflammation and "healing" of the underlying alveolar crest. This read­ justment or remodeling of the marginal periodontal structures is routine and undoubtedly occurs even during initial therapy. The coronal apposition of new support following definitive treatment of craters by osteoplasty appears to have less of a potential for coronal apposition of new support than those bony craters treated by curettage, although healing and thickening of the crestal cortex is a likely result of both methods of treatment. The intent of this paper is not to prejudge the advantage of one technique over the other but to demonstrate the potential for repair of osseous craters managed by curettage without os­ seous recon touring. 12,19,20

21,22

FIGURE 20. Histopathologic section taken directly through the center of an interdental crater. The inflammatory infiltrate is seen passing directly into the marrow cavity. This represents the space through which the interdental vessels pass. Some remnants of the transseptal fiber apparatus remain. D = Dentin, C = Acellular cementum, Pdl = Periodontal ligament, IC = interdental crater, F M = Fibrosis of marrow spaces, MI = Marginal inflammatory infiltrate, Ca = Calculus and plaque. (H & E, original magnification, x 28.)

SUMMARY

The clinical, histopathologic and radiographic de­ scription of the interdental crater has been reviewed. It is proposed that these common inflammatory lesions have a greater potential for repair than heretofore suggested. Several clinical cases are described in sup­ FIGURE 21. Artist's rendition of potential for repair in inter­ port of this thesis. dental osseous craters (1) preoperative view of crater (2), resorption of peaks of crater and "filling in" at base of defect.

they are lower in contrast when compared to films exposed at 65 kvp and 10 m a . Changes in vertical or horizontal angulation of the x-ray cone readily can produce distortion which can appear as favorable post­ operative changes in the supporting bone. The changes which often appear on the radiograph 14

ACKNOWLEDGMENTS

The author acknowledges gratefully the contributions of Mr. Arthur Bloom, histopathologic technician; Mr. Edward Entin and Mrs. Ida Nathan, medical photographers; and Mrs. Harriet Phillips, medical illustrator.

In reviewing this manuscript for consideration for publication, the editor ( H M G ) accepted the article but suggested to the author that other clinicians be con-

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suited for their opinions as to therapy of the crater by curettage. Two responded and their comments are appended. REFERENCES

1. McHugh, W. D.: The interdental gingiva. J Periodont Res 6: 227, 1971. 2. Cohen, B.: Pathology of the interdental tissues. Dent Practit Dent Rec 9: 167, 1959. 3. Cohen, B.: Morphologic factors in the pathogenesis of periodontal disease. Brit Dent J 107: 31, 1959. 4. Kohl, J. T . , and Zander, H . A . : Morphology of the interdental gingival tissue. Oral Surg 14: 287, 1961. 5. Holmes, C. H . : Morphology of the interdental pa­ pillae . J Periodontol 36: 455, 1965. 6. Fish, E . W.: Etiology and prevention of periodontal breakdown. Dent Progress 1: 234, 1961. 7. Ritchey, B . , and Orban, B.: The crests of the inter­ dental septa. J Periodontol 24: 75, 1953. 8. Manson, J. D . : Bone morphology and bone loss in periodontal disease. J Clin Perio 3: 14, 1976. 9. Ochsenbein, C , and Ross, S.: A reevaluation of osseous surgery. Dental Clinics of North America. Philadel­ phia, W. B. Saunders Co., 1969. 10. Prichard, J. F.: Criteria for verifying topographical changes in alveolar process after surgical intervention. Per­ iodontics 4: 71, 1966. 11. O'Connor, T. W . , and Biggs, N . L . : Interproximal bony contours. J Periodontol 35: 326, 1964. 12. Friedman, N.: Reattachment and roentgenograms. J Periodontol 29: 98, 1958. 13. Prichard, J. F.: The role of the roentgenogram in the diagnosis and prognosis of periodontal disease. Oral Surg 14: 182,1961. 14. Prichard, J. F.: The roentgenographic depiction of periodontal disease. J Am Soc Prev Dent 3: 1, 1973. 15. Glickman I., and Smulow, J. B.: Buttressing bone formation in the periodontium. J Periodontol 36: 365, 1965. 16. Updegrave, W. J.: Simplifying and improving in­ traoral dental roentgenography. Oral Surg 12: 704, 1959. 17. Updegrave, W. J.: Higher fidelity in intraoral roent­ genography. J Am Dent Assoc 62: 1, 1961. 18. Prichard, J. F.: Advanced periodontal disease, surgi­ cal and prosthetic management. ed. 2, Phila., W. B. Saunders Co., 1972. 19. Nabers, J. M . et al: Chronology, an important factor in the repair of osseous defects. Periodontics 2: 304, 1964. 20. Burnette, E . W.: Treatment of an isolated, severe osseous crater. J Periodontol 38: 148, 1967. 21. Patur, B. and Glickman, I.: Clinical and roentgeno­ graphic evaluation of the post-treatment healing of infrabony pockets. J Periodontol 33: 163, 1962. 22. Glickman, I.: Tissue regeneration following local peri­ odontal treatment. Dental Clinics of North America. Phila­ delphia, W. B . Saunders Co., 1962.

DISCUSSION by DR.

MARVIN ROSENBERG

A review of Bernard Moskow's manuscript, "Heal­ ing Potential In Periodontal Lesions: The Interdental Crater", enables one to comment on a multitude of

problems and shortcomings which exist in periodontics today. The weaknesses in the manuscript exist in several areas, namely: documentation and definition of objectives of therapy. The dependence upon radiographic evaluation and interpretation is a giant step backward for the profes­ sion in the area of clinical documentation. A quote from John Prichard's book, "Advanced Periodontal Disease," should be restated, and is not refuted by Moskow's microscopic study of human autopsy and surgical specimens. "The limitations of dental roent­ genographs in the diagnosis of periodontal disease are: 1. Roentgenograms do not show the periodontal pocket. 2. They do not specifically distinguish between the successfully treated case and the untreated case. 3. They do not record the morphology of bone deformities. 4. They do not show the structures of the buccal, lingual, and labial aspects of the tooth. 5. They show no soft to hard tissue relationship. 6. They do not record tooth mobility." If one is to engage in clinical research and documenta­ tion, techniques should be standardized so that studies could be reproduced and validated or challenged. Currently acceptable modes of clinical documentation in the study of new attachment procedures should include the following: 1. High quality diagnostic dental radiographs, pref­ erably with a grid, with a periodontal probe, or Hirschfeld's point, in position to the base of the deepest portion of the pocket. 2. Dental radiographs with the probe in place fol­ lowing entry into, and debridement of, the bony defect. The probe should be placed at the deepest portion of the bony defect in the long axis of the tooth. 3. Impressions and stone models of the defect at the time of surgery and at the time of reentry. 4. Clinical photographs, utilizing fixed focal length techniques, of the defect at the time of surgery and at reentry with and without periodontal probes in various positions within the defect. 5. Utilization of existing or established landmarks such as an amalgam restoration, as a reference point for the clinical, radiographic, and photo­ graphic interpretation of results. One must also describe the exact surgical technique that was utilized, postoperative management, the na­ ture of the occlusion, specific type of defect or defects under study, antibacterial measures, degree of root planing performed, type of periodontal dressing and its placement, particularly when one utilizes an open wound technique, duration of dressing for protection of an open wound, postsurgical instrumentation of the defect, methodology of plaque control, postsurgical

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waiting period before probing the defect, percentage of cases demonstrating nonregeneration, partial regen­ eration, complete regeneration, controls, etc. Moskow's statement, " B o t h radiology and photog­ raphy offer unlimited bounds for image distortion and deceivement, either accidental or deliberate, but to routinely subject patients to additional surgery simply for photographic purposes, in the author's mind, ex­ ceeds the bounds of ethical practice" contains infer­ ences which are counter-productive to the interests of clinical research. I cannot conceive of any of the front line clinical researchers within our specialty who would accidentally or deliberately deceive their colleagues with trick photography, or image distortion with the use of the radiograph. A well conceived and executed clinical study should be reproducible by other clini­ cians who would either validate or challenge results and conclusions. A s a matter of fact, the manuscript that is under review could fall under the umbrella of possible image distortion and deceivement, accidental to be sure. The reentry procedure is an opportune time to complete the documentation of new attachment proce­ dures with the use of photographs, impressions, radio­ graphs with probes in place, etc. Moskow infers that the sole purpose of a reentry procedure is "simply for photographic purposes", and this statement may or may not be true. In almost every instance of a new attachment procedure within an infrabony defect, the ultimate result will require a secondary procedure to eliminate residual osseous and soft tissue defects. This is a sound rationale for the reentry procedure at which time definitive management of residual defects takes place. The primary objective of a new attachment proce­ dure within a deep infrabony defect is to convert a deep, inoperable defect into a shallow defect by the deposition of a new cementum, periodontal ligament and alveolar bone. The shallow defect should be man­ aged definitively with a secondary stage procedure incorporating resective osseous surgery of the shallow osseous defect and appropriate soft tissue manage­ ment. The secondary stage procedure is also referred to as the reentry procedure. A t the present time, all periodontal regenerative modalities should be consid­ ered two-stage procedures: stage one is part of initial preparation designed to convert the deep infrabony defect into a shallow defect, and stage two is the definitive management of the residual shallow osseous defect and soft tissue lesion. If, on the other hand, the reentry procedure is performed simply for photo­ graphic purposes, this too may be a sound rationale for the reentry for the clinician who is engaged in clinical studies. A price must be paid, both by the clinician and the patient, if we are to propel ourselves out of the muck and mire of inadequate, inconclusive and nonreproducible clinical studies. Moskow's description of the osseous management of

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the crater, "the surgical removal of one peak of crater, thus creating a pyramid-like contour to the interproxi­ mal alveolus", is incorrect. A n osseous crater does not have a peak, but has two walls (facial and lingual), and the removal of one wall of the crater does not create a pyramid-like contour, nor does it eliminate the crater. A description of the shallow crater, and the resective osseous technique that one can employ to eliminate the shallow crater, is missing from the man­ uscript and should be presented for clarification. A description of the osseous resective procedure utilized in the management of the shallow crater is applicable for other shallow osseous defects. A n interdental osseous crater can be defined as a bony defect resulting from inflammatory periodontal disease where the proximal bone in the interdental area is destroyed and the facial and lingual proximal bony walls are intact or in a more coronal position. This determination should be made preoperatively by probing in both a horizontal and vertical direction in the interdental area. Probing in a vertical direction locates the base of the crater, and probing in a horizon­ tal direction from the facial and the lingual, locates the crests of the proximal bony walls. In the incipient osseous crater the relation between the convexity of the cervical line and the interdental bone is destroyed and the bone crest adjacent to the proximal surfaces of the tooth is concave. The bony spines at the facial and lingual proximal line angles become the most coronal points of the alveolar crest and are pyramid shape. Two walls of the bony pyramid are concave. One wall extends over the radicular surface of the root following the concavity of the cervical line on the facial or lingual aspects, and the second wall extends in a faciolingual direction to the adjacent bony spine. The third wall of the pyramid is relatively straight and bridges the defect in a mesiodistal direction. It extends from the peak of the bony spine on the distoproximal line angle of one tooth to the peak of the bony spine on the mesioproximal line angle of the adjacent tooth. A shallow crater can be defined as a two-wall (facial and lingual) interdental osseous defect of 2 to 3 mm in depth, and when adjacent to a multirooted tooth is within the dimensions of the root trunk. Multirooted teeth have a common root trunk which is that part of the root extending from the cervical line to the furcas. A deep crater can be defined as having a depth greater than 3 to 4 mm and when adjacent to a multirooted tooth, it extends apical to the root trunk. The root trunk for the mandibular first molar extends 3 to 4 mm below the cervical line. The facial furca is located approximately 3 mm below the cervical line and the lingual furca is approximately 4 mm below the cervical line. The root trunk for the mandibular second molar extends 2 to 3 mm below the cervical line. The facial furca is located approximately 2 mm below the cervical line and the lingual furca approximately 3 mm below

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the cervical line. Facial and lingual grooves on the root trunk start at the furca and shallow out as it approaches the cervical line. The depth of bony defects in terms of millimeters is not as significant for multirooted teeth as is the rela­ tionship of the defect to the root trunk. When the osseous defect extends apical to the root trunk, resective osseous surgery designed to eliminate reverse architecture will involve the fureas. A 3 mm osseous defect extending apical to the root trunk of a multi­ rooted tooth could be classified as deep and managed differently than a 4 mm osseous defect which does not extend apical to the root trunk. This latter defect could be classified as shallow and managed with resective osseous surgery which will not involve the furcas. When the definitions for the shallow and deep bony defects are related to root furcas, they assume great clinical significance and greatly influence the decision regarding the means by which the osseous lesion is managed. With the use of high-speed carbide burs or diamond stones in the presence of a generous supply of water, the facial and lingual walls of the crater are removed so that the base of the crater becomes the most coronal position of the interdental septum. Caution must be observed when high-speed cutting instruments are used close to the roots. A s a result of the removal of the proximal walls of the crater, a concave shape is devel­ oped when viewing the interdental septum in a mesiodistal direction. A t this stage all three walls of the pyramid-shaped bony spine at the proximal line angle are concave. H a n d instruments such as the Ochsenbein chisels, Wedelstaedt chisels, and heavy curets are used to remove the bony spines at the line angles to establish a horizontal mesiodistal crest. Further osseous contour­ ing is necessary to restore a convexity to the interdental bone in a faciolingual direction where the bone meets the proximal surface of the tooth. Radicular bone over the facial and lingual surfaces is then contoured by osteoctomy to produce a gradualsloping architecture similar to what had existed in health. The degree of scalloping is influenced by the tooth form and root anatomy and the relationship of the tooth to basal bone. A tooth that has a prominent root and considerable mesiodistal curvature requires greater scalloping; a tooth that is not prominent in the arch, or one which has a relatively flat mesiodistal surface, requires minimal scalloping. A t all times the radicular bone on the facial and lingual aspects must be apical to the interdental septum upon the comple­ tion of resective osseous surgery. Vertical grooves are placed in the interdental areas to narrow the faciolingual dimension of the interdental bone. They have the effect of narrowing the facio­ lingual dimension of the overlying interdental papillae and relocating the tip of the papilla beneath the protec­

J. Periodontol. December, 1977

tive confines of the proximal contact area. The apical limit of the vertical groove is the base of the most prominent portion of the facial vestibular plate. The interproximal limit of the vertical groove is the outer most facial and lingual extent of the proximal contact area. If a mandibular molar is prominent and the mesio­ distal curvature of the roots are great, each root is managed as a bicuspid. A parabolic curve is developed toward the furca, and a vertical groove is made extend­ ing apically from the furca. The greater the divergence of the roots the deeper the vertical groove can be made which decreases the tendency for gingival hyper­ plasia at the furca. In the management of the shallow crater, the furca is not invaded as a result of resective osseous surgery. If the base of a centrally-located crater is selected for the location of the interdental septum, the tech­ nique of resective surgery as previously described is followed; this locates the crest of the healed interdental septum beneath the contact areas of the teeth. If the base of a shallow crater is located toward the facial or lingual, osteoplasty and osteoectomy is required pri­ marily on one side of the defect. This approach places the crest of the interdental septum to either the facial or lingual side of the contact area. Contraindications for resective osseous surgery in­ clude anatomical considerations, such as the presence of a high and prominent external oblique ridge in the mandibular molar region, a maxillary sinus which ap­ proximates the bony lining of osseous defects in the maxillary posterior quadrant, close root proximity with insufficient interdental space for the placement of the papillae, and the inability to establish a physiologic contour. The deep proximal osseous defect measuring more than 3 to 4 mm or one which extends apical to the root trunk of adjacent multirooted teeth, cannot be managed satisfactorily with definitive osseous resective surgery. If an attempt were made to totally eliminate the osseous defect and establish physiologic bony con­ tours, too much supporting alveolar bone would be sacrificed, and the furcas of the multirooted tooth would be exposed. The therapist must either compro­ mise his objectives and accept reverse architecture in situations of this type or utilize alternatives such as strategic extraction, root resection, or attachment ap­ paratus reconstructive procedures. Moskow's statement that there are "those practition­ ers striving for minimal immediate postoperative inter­ proximal pocket depth", infers, and correctly so, that there are those practitioners who do not strive for minimal immediate postoperative interproximal pocket depth. Herein lies one of the greatest controversies which exist in clinical periodontics today: namely, the lack of agreement as to the objectives of periodontal therapy, and the lack of agreement as to the clinical

Volume 48 Number 12

modalities which are most desirable in attaining a definable end-point that is predictable, easily executed, and maintainable. Moskow states that it has been his experience that "curettage and debridement of interdental craters with­ out osseous contouring often results in favorable changes in the crestal alveolus." Five cases are pre­ sented as "documentation of a direct and simple method of treating interdental craters without osseous surgery." There is ample evidence to demonstrate that initial mouth preparation, and surgical curettage procedures, often times will induce favorable changes in the crestal alveolus. A s a matter or fact, this is one of the objectives of initial mouth preparation; namely, to reduce the level of the inflammatory response, control or eliminate local etiologic factors, negate occlusal factors, and modify the morphology of various types of osseous defects. These favorable changes should be looked upon as mid-point and not end-point objectives of periodontal management. The mid-point objectives that seem acceptable to Moskow are not predictable, reproducible, nor maintainable with current plaque removal procedures. The acceptance of residual pocket depth and reverse architecture as an objective of therapy, when comparable lesions lend themselves for definitive osseous and soft tissue management resulting in minimal sulcular depth with "physiologic" gingival and osseous contours, defies our understanding of the etiology and pathogenesis of inflammatory periodontal disease. It matters little whether a patient, prior to the initiation of periodontal disease, presented with the so-called "ideal alveolar process." It has been our clinical experience, however, that performing definitive resective osseous surgery to eliminate shallow bony defects and creating an "ideal alveolar process," in conjunction with proper soft tissue management, plaque control, etc., will result in a definable endpoint that is predictable, reproducible, and maintaina­ ble. Bacterial plaque is the main etiologic agent in the initiation and perpetuation of inflammatory periodon­ tal diseases. A n environment that encourages plaque retention or that makes plaque removal difficult or impossible, compromises the health of the periodon­ tium. The periodontal pocket contains subgingival plaque almost to the level of the epithelial attachment which is virtually impossible for the patient to remove on a daily basis with current plaque control procedures. It is also impractical for the therapist to keep the pocket areas free of plaque because new plaque begins to form almost immediately after its removal, and many defects are inaccessible to complete instrumen­ tation. The objectives of periodontal surgery should include the elimination of all pockets, restoration of "physio­ logic" gingival and osseous contours, and the establish­

The Interdental Crater

765

ment of an adequate zone of attached gingiva, all of which is a prerequisite for adequate plaque control and preventive periodontics. A review of the case reports shows that they are rather nonconclusive, and are, in all probability, not interdental craters but combination defects. The most interesting case is N o . 2 in which an isolated deep osseous defect is present between the mandibular right lateral incisor and cuspid in a 15-year-old boy undergo­ ing orthodontic therapy and has a preexisting untreated puberty gingivitis. It is interesting to note that an external resorptive lesion was noted on the lateral incisor, and a fistulous opening was present which might be indicative of a recent occurrence of an acute periodontal abscess. The remarkable degree of fill that one can assume from radiographic examination alone creates the suspicion that the osseous defect was the result of an acute inflammatory episode. In conclusion, I would like to make a plea for a standardization of techniques for clinical documenta­ tion, and the acceptance of model systems that can be utilized and are reproducible in testing the efficacy of various clinical modalities. D r . Marvin Rosenberg 901 N . Flagler Drive W . Palm Beach, F l a . 33401

Letter to the Editor: Y o u have asked D r . John Prichard and D r . Marvin Rosenberg to comment on my article, "Healing Poten­ tial in Periodontal Lesions. The Interdental Crater," and their critiques will be published along with my manuscript. The discussion of D r . Rosenberg is ex­ tremely long and critical of my paper, and in very few instances addresses itself directly to the material pre­ sented. Over 3000 words of Journal space (certainly longer than the manuscript itself) were allowed for his commentary, much of which was a detailed description of the morphologic characteristics of the crater and the treatment commonly employed to eliminate these de­ fects. The therapy he described is one that can be noted in most standard texts on periodontics and has been reported innumerable times in the periodontal literature. It is presented in such a manner as to imply that this is the only acceptable and effective manner of managing interdental craters and that anyone daring to question this mode of therapy would be committing sacrilege. While periodontal therapy (despite the vari­ ety of philosophical approaches) is extremely successful in most instances, periodontics is a long way from being an exact science, and an environment which

766

J. Periodontol. December, 1977

Moskow

encourages questioning and discussion of scientifically unsupported dogma is, in my mind, extremely healthy for our profession. The material in my paper was presented in the form of case reports documented by clinical descriptions and accurate radiographs. It was accompanied by a philosophy of approach to treatment based on mor­ phologic and histologic examination of human tissue specimens and careful clinical examinations of treated cases over a period spanning more than 20 years of practice limited to Periodontics. It was never presented as being a controlled clinical experiment on human patients. Furthermore, the examples shown were only a few of virtually hundreds of similar results I have observed. If the use of accurate and duplicatable radiographs and careful clinical examinations is "taking a giant step backward for the profession," I would like to know what other practical clinical modalities we have available to us for assessing the results of our therapy. The shortcomings of x-rays were adequately described in my paper, but I continue to support the thesis that this modality, properly performed and inter­ preted, is an invaluable tool in assessing the results of our treatment. I also continue to maintain that re­ peated surgical exposure of treated lesions for the purpose of observing the results of therapy is unnec­ essary, traumatic and is of no real value to the pa­ tients. In addition, the employment of multiple surgi­ cal procedures for treatment of the same lesion should be done with considerable thought and should have the potential for providing a much improved clinical situation for the patient. I sincerely regret that D r . Rosenberg feels that questioning procedures that are in routine usage in periodontics is "counterproductive to clinical research." Similarly, if my material falls "under the umbrella of image distortion and deceivement," he would have been much more prudent in expending his words and directing his comments to the exact areas of my paper where he felt the shortcomings lay. In line with my feelings that there are often multiple ways of treating a particular periodontal lesion success­ fully, I have expressed a point of view in my paper which allows for the understanding of methods of therapy other than the one described. I am indeed anxious to try alternative approaches to treatment as they become available. A l l periodontists, no matter what their approach to therapy, have as their ultimate aim the maintenance of the teeth in a continued state of periodontal health for the life of their patients. T o discourage by innuendo alternative treatment methods which could be less time-consuming, less traumatic and less costly to our patients is, in D r . Rosenberg's terminology, "counter­ productive to our profession."

DISCUSSION

bv D R . JOHN PRICHARD I am in general agreement with the theme of this paper. The therapy as presented is rational, and the paper tends to direct periodontists away from their assumed role as engineers and architects to their proper role as therapists. Some confusion could have been avoided by the precise use of terms and description of anatomic rela­ tionships. A l l interdental bony defects are not craters, and a distinction should be made between the proce­ dures for osteoplasty and ostectomy. Gingival form does not dictate bony contour. However, gingiva and bone are consistent with one another when the oral soft tissue and bone are in their original state of health and not previously affected by disease (periodontitis). The gingival papilla has two peaks because it is blocked in the center by the contacting surfaces of contiguous teeth. Where teeth do not make contact, there is no gingival " c o l , " and there is no col where the gingiva has receded. The underlying interalveolar bony crest does not follow the contour of the col; it is usually flat in the molar region. There is no evidence that interal­ veolar crestal form is normally concave. Exostoses are genetic variations, but they are aberrations and do not represent the normal contour of alveolar process. Osteoplasty is a well-established procedure to reduce thick bony margins to allow better adaptation of mucoperiosteal flaps to marginal bone and cementum. The ostectomy procedure is used to reshape craters and other defects in an effort to eliminate the periodon­ tal pocket. Pocket depth can be reduced immediately by ostectomy, but there is no long-term evidence to support the value of this procedure. A n accurate perspective cannot be obtained by periodontists who treat only teeth that can be restored to an "ideal" form and order the extraction of more seriously af­ fected teeth. This method of practice has contributed to the perpetuation of many misconceptions in perio­ dontics. Confusion also exists because many periodontists consider the pocket and the crater as the disease itself; these defects are the result of the disease. After healing following rational therapy, it is possible for the perio­ dontium to be maintained in health with deep gingival crevices and bony defects. They are abnormalities caused by the disease. The recession created intention­ ally by surgical intervention to eliminate pockets is also abnormal; periodontitis is a destructive disease, and it leaves scars or abnormalities in its wake. H o w ­ ever, these scars are neither an indication for extraction nor for repeated surgical procedures. I agree with the author that craters need not be treated by ostectomy. 1

2

Bernard S. Moskow, D . D . S . , M . S c . D

Volume 48 Number 12

The Interdental Crater

I agree completely with the statement in the paper about surgical reentry for photographic purposes; it can be justified only in the study of new procedures. The quotation emphasizing the inadequacy of preop­ erative and postoperative radiographs for documenta­ tion is correct, but it should also be stated that accurate radiographs are always essential for documentation. Standards for accurate documentary photographs were also presented. Photographs satisfying these standards are not observed in the literature any more often than accurate radiographs. The observation of reinforcement of the crestal area by the apposition of new bone at the first sign of resorption is interesting. The late H . Sicher often stated that injury to bone stimulated both bone resorp­ tion and bone apposition. Increased density of bone surrounding resorptive lesions is often observed radiographically and, from the reproduction furnished, ap­ pears to be present in Figure 19. Bone of increased density is also observed radiographically around per­ iapical lesions. However, clinically and radiographi­ cally, both pulpal and periodontal disease present resorptive lesions. The Zerox-type copies of illustrations available for this review show only the gross outline of the illustra­ tions used in the paper, and no definite conclusions can be drawn for them. A n image of the inferior border of the mandible can be seen on the radiographs in Case I. Film placement and vertical angulation required to produce this image causes gross distortion in the crestal region. The fact that the before and after radiographic images were equally distorted does not 3

767

make them accurate for interpretation or documenta­ tion. Case II is a 15-year-old boy undergoing orthodontic treatment. G o o d regeneration can be expected follow­ ing the described treatment at that age. The outline of the radiographic image in Case I V (Fig. 12) shows a hemiseptum, not a crater. The postoperative film shows the appearance that would be expected following rational therapy. The radio­ graphs in Case V also appear to show the repair that should be expected from the therapy as described. The side walls of craters, if thin, recede after expo­ sure and occasionally some new bone may form on the crest, but the filling in of a crater as shown in the drawing in figure 21 is entirely an artist's conception. However, the potentional for repair following rational therapy for periodontal bony lesions is better than is generally believed. 4

REFERENCES

1. Glossary of terms: J Periodontol Supplement, Janu­ ary, 1977. 2. Prichard, J. F.: Treatment goals. Clark, J. W. (ed). Clinical Dentistry. Hagerstown, Harper and Row, 1976. 3. Prichard, J. F.: Criteria for verifying topographical changes in alveolar process after surgical intervention. Per­ iodontics 4: 71, 1966. 4. Prichard, J. F.: Combining surgical techniques. Clark, J. W. (ed). Clinical Dentistry. Hagerstown, Harper and Row, 1976.

John F . Prichard 3833 Camp Bowie B l v d Fort Worth, Texas 76107

Announcement THE 1978 ORB AN MEMORIAL PROGRAM The 1978 meeting of the American Academy of Periodontology will be held in Phoenix, Arizona, September 27-30, 1978. Compe­ tition for the Balint Orban Memorial Prize among graduate and postgraduate students in periodontology will be held at this meeting. The Balint Orban Prize, including a $200 award from the Ameri­ can Academy of Periodontology, will be presented to the person giving the best paper based upon his or her research. The winning paper will be published in the Journal of Periodontology. All other papers will be submitted to the editors of the Journal of Periodontol­ ogy for consideration for publication. Eligibility Students currently in graduate or postgraduate training periodon­ tology programs, and those who have completed their training within the past 18 months, are eligible to enter the competition.

Procedures (Items 2 and 3 apply to those papers selected for the program) 1. Each interested student should submit a curriculum vitae, title and abstract (300 words) of the paper to the address listed below no later than May 1, 1978. 2. The student then should prepare a manuscript suitable for publi­ cation in the Journal of Periodontology based upon the research work to be presented. This should be completed by the time of the 1978 Academy Meeting. 3. The student then will present his research orally at the 1978 Academy Meeting. Fifteen minutes for the presentation and 5 minutes for discussion are allowed for each presentation. Please send curriculum vitae and abstracts to: Dr. James H . Butler Medical College of Virginia, School of Dentistry, Virginia Commonwealth University, Box 637, Richmond, Virginia 23298.