The Relationship Between the Width of Keratinized Gingiva and Gingival Health by

NIKLAUS P. LANG*

HARALD LÖE**

INTRODUCTION

IN MAN THE KERATINIZED gingiva includes the free and the attached gingiva and extends from the gingival mar­ gin to the mucogingival junction.1 The width of the keratinized gingiva may vary between 1 and 9 mm.2, 3

The characteristics of the gingiva on the facial aspect have been described by several authors.17 However, only one recent study has reported on the width of the lingual keratinized gingiva of the mandible.7

Although not substantiated, it is generally believed that an adequate width of keratinized gingiva is im­ portant for maintaining gingival health. This has resulted in the introduction of numerous surgical procedures to increase the width of gingiva.830 However, the question FIGURE 1. Clinical photographs showing the mucogingival of how much gingiva is "adequate" has not been inves­ junction a) without stain b) after application of the Schiller tigated. IKI solution. The purpose of the present investigation was to ex­ amine the width of the facial and lingual keratinized to the nearest 0.5 mm from the gingival margin to the gingiva and to determine how much keratinized gingiva mucogingival junction using a specially graded perio­ is adequate for the maintenance of gingival health. dontal probe. The depth of the gingival crevices was also measured. In order to compare the results of the present study to results from previous studies the width MATERIAL AND METHODS of attached gingiva was determined by subtracting the Thirty-two dental students between 19-29 years of crevicular depth from the width of keratinized gingiva. age with no pathologic pockets performed supervised Gingival exudate was assessed37 on all (116) buccal oral hygiene (daily supervision with the Plak-Lite® dis­ and lingual surfaces which had 2 mm or less of kera­ closing system)31 for 6 weeks. Following this period, tinized gingiva. In addition, the amount of gingival exu­ the gingiva of all buccal and lingual tooth surfaces was date from 118 tooth surfaces randomly selected from assessed using the Gingival Index system.32 Oral hy­ a total of 371 which had 2.5 to 3.0 mm gingiva was giene was scored on all surfaces according to the criteria measured. Only plaque free surfaces were scored. of the Plaque Index system.33 The identification of the mucogingival junction was facilitated by staining with

34 Schiller's IKI solution. Using this method, the epithe­ RESULTS lium of the alveolar mucosa yielded an iodine-positive After the six weeks of controlled oral hygiene the reaction while the keratinized gingiva was iodine-nega­

3436 mean individual Plaque Index (PI I) was 0.22 (range tive, (Figure 1 a,b). After application of the Schiller 0.00-0.57). The mean individual Gingival Index (GI) solution, the width of keratinized gingiva was measured was 0.09 (range 0.04-0.25). The crevicular depth aver­ *Research Associate, Department of Periodontology, Royal aged 1.0 mm (range 0.5-1.5 mm). Dental College, Aarhus, Denmark. **Professor and Chairman, Department of Periodontology, From a total of 1406 tooth surfaces, 1168 were com­ Royal Dental College, Aarhus, Denmark. pletely plaque free.

623 624 Lang and Löe J. Periodontol. October, 1972

MEAN WIDTH OF KERATINIZED GINGIVA

FIGURE 2. Pattern of variation in the mean width of keratinized gingiva in 32 individuals (19-29 years of age) with excellent oral hygiene and healthy gingiva.

The facial keratinized gingiva was widest in the area gingiva was generally 0.5-1 mm wider than in the of upper and lower incisors and narrowest adjacent to mandible (Figure 2). the maxillary and mandibular canines and first pre­ molars (Figure 2). The lingual gingiva of the lower Most surfaces (> 80%) with 2.0 mm or more kera­ jaw exhibited its greatest width in the area of the pre­ tinized gingiva were clinically healthy, (Figure 3) and molars and molars. The incisors showed the narrowest 76% of these same surfaces failed to show gingival lingual gingiva (Figure 2). In the maxilla the facial exudation (Figure 4). On the other hand, all surfaces

PERCENTAGE OF SURFACES

FIGURE 3. Proportion of Gingival Index score 0 to 1 to 2 in surfaces of varying width of keratinized gingiva (1.0-25.0 mm) of 1168 plaque free teeth. Volume 43 Keratinized Gingiva and Gingiva Health62 5 Number 10

PERCENTAGE OF SURFACES

FIGURE 4. Proportion of gingival exudate measurements 0 to 03-0.5 to 0.6-1.0 to greater than 1.0 mm in surfaces of varying width of keratinized gingiva (1.0-3.0 mm) of 234 plaque free teeth.

with less than 2.0 mm of keratinized gingiva exhibited ATTACHED GINGIVA OF BUCCAL SURFACES clinical inflammation and varying amounts of gingival exudate (Figures 3, 4). Generally, the Gingival Index and gingival exudate scores increased as the width of the keratinized gingiva decreased (Figures 3, 4). The maximum score during this examination was GI = 2 (moderate inflammation) which occurred only in sur­ faces whose width of keratinized gingiva was 2 mm or less (Figure 4).

Figure 5 compares the distribution of variation of the width of attached gingiva found in the present study to that of previous studies.2' 3,7 The similarity between these results is apparent.

DISCUSSION AND CONCLUSION

The present investigation has shown that the pattern of variation in the width of the facial keratinized gin­ giva minus the crevicular depth agrees with previous studies on the width of attached gingiva.2, 3, 5,7 Simi­ larly, it corroborates recent data on the width of the lingual attached gingiva.7 In this study the width of the lingual keratinized gingiva varied between 1 and 8 mm. The smallest width was usually seen in the area of the anterior teeth, and the widest gingiva was found adjacent to premolars and molars. This pattern of varia­ tion is almost the reverse of that of the facial gingiva.

The present material has also clearly demonstrated that although tooth surfaces may be kept free of clin­ ically detectable plaque, areas with less than 2 mm of keratinized (which means less than 1 mm of attached) FIGURE 5. Comparison of the pattern of variation in the gingiva persisted to remain inflamed. The fact that mean width of attached gingiva in the present study to inflammation persisted in these areas irrespective of those of previous studies. 626 Lang and Löe J. Periodontol. October, 1972 the presence or absence of frenum insertions, suggests mm gingiva. Only plaque free surfaces were scored. that the inflammatory situation in the gingiva is not Previous observations on the width and the pattern of a result of only mechanical irritation from these struc­ variation of keratinized gingiva were confirmed. It was tures. Rather it is conceivable that a movable gingival demonstrated that gingival health is compatible with a margin would facilitate the introduction of microorgan­ very narrow gingiva. However, in areas with less than isms into the gingival crevice resulting in a thin sub­ 2 mm keratinized gingiva inflammation persisted in gingival bacterial plaque which would be difficult to spite of effective oral hygiene. It is suggested that 2 mm detect and not easily removed by conventional tooth- of keratinized gingiva (corresponding to 1 mm attached brushing. gingiva in this material) is adequate to maintain gin­ gival health. The regions which consistently showed the narrowest width of keratinized gingiva were the lingual surface of the lower anteriors and the buccal surface of the REFERENCES lower canines and first premolars. However, the study 1. Orban, B.: Clinical and histologic study of the sur­ has shown that these surfaces which averaged nearly 3 face characteristics of the gingiva. Oral Surg. 7:827-841, mm in width should be adequate to maintain gingival 1948. health. Although not a problem from a preventive point 2. Bowers, G.: A study of the width of attached gin­ giva. J. Periodont. 54:201-209, 1963. of view, the narrow keratinized gingiva on the lingual 3. Ainamo, J. and Löe, H: Anatomical characteristics of the lower anteriors may pose a problem in prostho- of gingiva. A clinical and microscopic study of the free dontic and periodontal treatment. For example, it is and attached gingiva. J. Periodont. 57:5-13, 1966. required that if lower partial removable appliances are 4. Fehr, C. and Mühlemann, H. R.: The surface of the to be equipped with a lingual bar, the lingual area should free and attached gingiva studied with the replica method. Oral. Surg. 5:649-655, 1955. have a minimum width of 4 mm keratinized gin­ 5. Borowik, D., Grabowska, M., Kaczynska, W., Karas, 38 39 giva. ' This requirement may be difficult to satisfy Z., Lembas, K., Lisiecka, K., Martyka, D., Mazurek, I., in the average patient since the mean width of the lin­ Ostrysz, W. and Pruchla, M.: Measurements of the width gual gingiva adjacent to the lower anterior teeth is of gums, the depth of epithelial attachments and oral ves­ usually less than 3 mm. tibule in children and adolescents. Czas. Stomat. 22:989- 994, 1969. It is apparent in periodontitis that pathologic pockets 6. Bernimoulin, J. P., Son, S. and Regolati, B.: Bio- metric comparison of three methods for determining the may easily extend beyond the mucogingival junction. mucogingival junction. Helv. odont. Acta 75:118-120, Although procedures have been devised for correction 1971. this problem when it occurs on the facial aspect, to 7. Coppes, L.: Routine-Sulcusdieptemetingen in de the best of our knowledge, modern periodontal surgery parodontologie. Het belong-de betrouwbaarheid-de toepass- offers no specific method for increasing the width of ing. Academisch proefschrift. Universiteit van Amsterdam. 117-135, 1972. keratinized gingiva on the lingual surface of the lower 8. Gottsegen, R.: Frenum position and vestibule depth incisors. in relation to gingival health. Oral Surg. 7:1069-1078, 1954. Furthermore, since it would appear from this study 9. Nabers, C. L.: Repositioning the attached gingiva. J. Periodont. 25:38-39, 1954. that less gingiva is needed to maintain health than gen­ 10. Grupe, H. E. and Warren, R. F.: Repair of gingival erally believed, a critical reappraisal of the indications defects by a sliding flap operation. J. Periodont. 27:92-95, for performing anyone of the many surgical procedures 1956. available for increasing the width of gingiva must be 11. Ariaudo, A. A. and Tyrrell, H. A.: Repositioning undertaken. and increasing the zone of attached gingiva. J. Periodont. 25:106-110, 1957. 12. Ochsenbein, C: Newer concepts of mucogingival SUMMARY surgery, J. Periodont. 57:175-185, 1960. 13. Bohannan, H. M.: Studies in the alterations of The study undertook to examine the width of the vestibular depth. I. Complete Denudation. J. Periodont. facial and lingual keratinized gingiva and to determine 55:120-128, 1962. how much gingiva is "adequate" for the maintenance 14. Bohannan, H. M.: Studies in the alterations of ves­ of gingival health. After 6 weeks of supervised oral tibular depth. II. Periosteum retention. J. Periodont. 55: 354-359, 1962. hygiene the gingival health of 1406 buccal and lingual 15. Corn, H.: Periosteal separation— its clinical sig­ surfaces in 32 dental students was assessed according nificance. J. Periodont. 55:140-152, 1962. to the criteria of the Gingival Index system. The width 16. Corn, H.: Edentulous area pedicle grafts in mu­ of keratinized gingiva was measured after the applica­ cogingival surgery. Periodontics 2:229-242, 1964. tion of the Schiller IKI solution. Gingival exudation was 17. Friedman, N.: Mucogingival Surgery: The apically repositioned flap. J. Periodont. 55:328-340, 1962. measured on all buccal and lingual surfaces which had 18. Wilderman, M. N.: Repair after periosteal reten­ 2 mm or less of keratinized gingiva and in a randomly tion procedure. J. Periodont. 54:487-503, 1963. selected number of tooth surfaces with more than 2 19. Edlan, A. and Mejchar, B.: Parodontologisch in- Volume 43 627 Number 10 Keratinized Gingiva and Gingiva Health

dizierte Vertiefung des unteren Mundvorhofes. Parodon- 30. Hilming, E. and Jerv0e, P.: Surgical extension of tologie 75:87-94, 1964 vestibular depth. Tandlaegebladet 74:329-343, 1970. 20. Friedman, N. and Levine, L.: Mucogingival Sur­ 31. Lang, N. P., 0stergaard, E. and Löe, H.: A fluor­ gery: Current status. J. Periodont. 55:5-21, 1964. escent plaque disclosing agent. J. periodont. Res. 7:59-67, 21. Wilderman, M. N. and Wentz, F. M.: Repair of 1972. a dentogingival defect with a pedicle flap. J. Periodont. 32. Löe, H. and Silness, J.: Periodontal disease in preg­ 56:218-231, 1965. nancy. I. Prevalence and severity. Acta odont. scand. 27: 22. Nabers, J. M.: Free gingival grafts. Periodontics 533-551, 1963. 4:243-245, 1966. 33. Silness, J. and Löe, H.: Periodontal disease in preg­ 23. Ross, S., Maimed, E. H. and Amsterdam, M.: The nancy. II. Correlation between oral hygiene and periodontal contiguous autogenous transplant — its rationale, indica­ condition. Acta odont. scand. 22:121-135, 1964. tions and technique. Periodontics 5:246-255, 1966. 34. Fasske, T. and Morgenroth, K.: Comparative 24. Cohen, D. W. and Ross, S. E.: The double papillae stomatoscopic and histochemical studies of the marginal repositioned flap in periodontal therapy. J Periodont 59:65- gingiva in man. Parodontologie 72:151-160, 1958. 70, 1968. 35. Zabinska, O.: Die Anwendung der Schillerschen 25. Gordon, H., Sullivan, H. C. and Atkins, J. H.: Jodprobe als Index der Zahnfleisch — Entziindungsinten- Free autogenous gingival grafts. II. Supplemental find­ sität im Verlauf der Parodontopathien. Parodontologie 22: ings— Histology of the,graft site. Periodontics 6:130-133, 65-73, 1968. 1968. 36. Mutschelknauss, R.: Indikation und Operations- 26. Sullivan, H. C. and Atkins, J. H.: Free autogenous methoden der mucogingivalen Chirurgie. Dtsch. zahnärztl. gingival grafts. I. Principles of successful grafting. Perio­ Z. 26:541-556, 1971. dontics 6:5-13, 1968. 37. Löe, H. and Holm-Pedersen, P.: Absence and pres­ 27. Sullivan, H. C. and Atkins, J. H.: The role of free ence of gingival fluid in normal and inflamed gingivae. gingival grafts in periodontal therapy. Dent. Clin. N. Amer. Periodontics. 5:171-177, 1965. 133-148, 1969. 38. Tryde, G. and Brantenberg, F.: The sublingual bar. 28. Wade, B. A.: Vestibular deepening by the technique Tandlægbladet 69:873-885, 1965. of Edlan and Mejchar. J. periodont. Res. 4:300-313, 1969. 39. Derry, A. and Bertram, U.: A clinical survey of 29. Brackett, R. C. and Gargiulo, A. W.: Free gingival removable partial dentures after 2 years usage. Acta odont. grafts in humans. J. Periodont. 47:581-586, 1970. scand. 25:581-598, 1970.

Announcements

CONTINUING EDUCATION COURSES ARMY DENTAL RESEARCH INSTITUTE EARN AWARD FALL SEMESTER—1972 AT ARMY SCIENCE CONFERENCE COLLEGE OF MEDICINE AND DENTISTRY On June 21, 1972 the United States Army Institute of Dental OF NEW JERSEY Research team of Brigadier General Surindar N. Bhaskar, NEW JERSEY DENTAL SCHOOL Colonel Arthur Gross and Colonel Duane E. Cutright presented 201 Cornelison Avenue a study of their work with the pulsating water jet device at Jersey City, N.J. 07304 the Army Science Conference at West Point. Their contribu­ tion to Army research and development was judged to be Course Title—P-l Periodontics for the General Practitioner; among the nine most significant in all areas of research. Faculy—Dr. A. Formicola and Staff; Dates 9-20-72 (Wed.); Fee—$40.* Scientists from throughout the Army Research and Develop­ ment Command had submitted a total of 497 proposals for Course Title—CE-2 Getting Prevention Through To Your papers to be presented at the conference. Of these, 100 were Patients; Faculty—Dr. J. Mittelman; Dates—10-18-72 (Wed.); selected by a panel of Judges for presentation. Papers selected Fee—$50. represented all areas of Army research, and included such Course Title—CE-3 Principles of Occlusion; Faculty—Dr. N. subjects as communications, computer systems and nuclear Guichet; Dates— 11-13, 14, 72 (Mon. and Tues.); Fee—$95 research as well as medical studies. (Dentists) $60 (Aux.). At the end of the week-long conference, the panel of scien­ *No tuition for N.J. dentists. However, a $10. registration fee tists selected the nine best papers presented. Authors of these is required for each course. studies received medals, certificates, and cash awards. The studies conducted at the United States Army Institute FOR INFORMATION AND APPLICATION, WRITE TO: of Dental Research led to the use of the pulsating water jet devices in the debridement of combat wounds in Vietnam. Dr. Daniel Isaacson These techniques have now been adopted for the management Director of Continuing Education of wounds in all parts of the body. New Jersey Dental School 201 Cornelison Avenue This is the first time that dental research has won such an Jersey City, New Jersey 07304 award at the Army Science Conference.