The International Journal of Periodontics & Restorative Dentistry

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1 The International Journal of Periodontics & Restorative Dentistry

2 55 Supracrestal Gingival Tissue Measurements in Healthy Human Periodontium Eliane Porto Barboza, CD, MScD, DScD* Raul Feres MonteAlto, CD, MO** Vinícius Farias Ferreira, CD*** Waldimir Rocha Carvalho, CD, MO**** This randomized, blinded study compared, contralaterally, the dimensions of supracrestal gingival tissue (SGT) in healthy human periodontium. Sulcular probing reaching the crestal bone was performed in 100 dental students (400 teeth [first molars and second premolars] and 1,600 sites). Contralateral measurements were statistically analyzed by one-way analysis of variance. SGT measurements ranged from 1.0 to 6.0 mm. Contralateral measurements showed no statistical difference (P =.096). Measurement of SGT contralaterally prior to crown lengthening or restorative procedures may dictate the needed amount of bone removal or tooth preparation into the sulcus. (Int J Periodontics Restorative Dent 2008;28:55 61.) *Chairwoman, Master of Science in Dentistry Program, Federal Fluminense University; Professor, Department of Periodontology, Brazilian Institute of Periodontology, Rio de Janeiro, Brazil. **Professor, Department of Periodontology, Federal Fluminense University, Rio de Janeiro, Brazil. ***Graduate Student, Department of Periodontology, Federal Fluminense University, Rio de Janeiro, Brazil. ****Clinical Instructor, Department of Prosthodontics, Brazilian Institute of Periodontology, Rio de Janeiro, Brazil. Correspondence to: Dr Eliane Porto Barboza, Brazilian Institute of Periodontology, Av. Presidente Wilson 165/810, Centro, Rio de Janeiro, RJ Brazil ; fax: ; barbozae@uol.com.br. The principles of biologic width have been widely discussed in the literature and used as clinical guidelines during the evaluation of periodontal, restorative, and prosthetic interrelationships. The average measurements of the gingival sulcus depth (0.69 mm), the epithelial attachment (0.97 mm), and the connective tissue attachment (1.07 mm) were studied by Gargiulo et al 1 in These measurements may vary at each tooth or at different sites on the same tooth. A definite proportional dimensional relationship between the dentogingival junction and the other supporting tissues of the tooth was also observed. The term biologic width was first used by Cohen 2 in 1962 as a length that included the junctional epithelium and the connective tissue fibers, which, according to Gargiulo et al, 1 is 2.04 mm. The term supracrestal gingival tissue (SGT) was introduced by Smukler and Chaibi 3 in 1997 as the tissue from above the alveolar crest to the gingival margin, and averages 2.73 mm, based on the Gargiulo et al study. 1 The most common causes of SGT violation are root fracture or perforation, dental resorption, prosthetic preparation, and caries. Therefore, it is Volume 28, Number 1, 2008

3 56 Fig 1 (left) Schematic drawing of sulcular probing. Measurements were recorded from the gingival margin to the top of the alveolar crest. Fig 2 (right) Clinical view of sulcular probing. of integral importance to the maintenance of a healthy periodontium that no restorative effort violates the SGT. Impingement upon the attachment apparatus can result in inflammation, and bone can be lost in an attempt to reestablish this dimension. 4,5 Treatments to manage the violated tooth include strategic extraction, osseous surgery (tooth lengthening), and, in selected cases, forced eruption. The crown-lengthening procedure aims to remove bone and apically position the soft tissue to permit formation of a new SGT complex Classic studies determined that sufficient bone should be resected to permit 3.0 mm of sound tooth structure above the crest of bone to house the supracrestal fibers, junctional epithelium, and gingival sulcus. 5,8,11 18 However, other studies have recommended 3.5 to 4.0 mm, mm, mm, 20 and 5.0 to 5.25 mm. 21 This physiologic dimension is also implicated when a prosthetic margin is placed subgingivally. Subgingival margins often extend beyond the gingival crevice into the junctional epithelium and connective tissue, 22 causing marginal and papillary gingivitis, which may progress to periodontitis. 16 Several investigations have suggested that the margin should be placed at different locations within the gingival crevice, which varies from 0.5 to 3.0 mm. 5,15,22 34 Although these studies report variations in measurements for bone removal or tooth preparation, the standardized 3.0 mm for crown lengthening and 0.5 mm for tooth preparation into the gingival sulcus still dictate restorative dental therapy principles. However, such standardized measurements are based on necroscopic or empiric observations, with no individualized data. The purpose of this study was to measure and compare contralaterally the dimensions of SGT in healthy human periodontium. Method and materials The randomized, blinded clinical trial was approved by the Ethics Committee of the Federal Fluminense University, Faculty of Medicine (CEP/CMM/HUAP#95/03), in full accordance with the ethical principles of the World Medical Association Declaration of Helsinki. This study comprised 100 dental students (50 women and 50 men), aged between 20 and 34 years (mean, ± 2.7 years), with clinically healthy periodontium who were recruited from Federal Fluminense University Dental School, Rio de Janeiro, Brazil. Since the objective of this study was to measure healthy periodontium, young dental students with fully erupted teeth, presenting no periodontal disease, and showing a high level of oral hygiene represented the best sample for this research. All students voluntarily signed an informed consent document, which was approved by the Ethics Committee of the Federal Fluminense Medical Faculty. Participants presenting with contralateral missing or restored teeth, periodontal disease, orthodontic therapy, pregnancy, a smoking habit, or who used any medications were excluded from this study. Contralateral sulcular probing, from the gingival margin to the top of the alveolar crest, using a NCPH-15 probe (Hu-Friedy), were performed at 400 teeth under local anesthesia (mepivacaine 1/100,000, DFL) with the objective of measuring the SGT (Figs 1 and 2). Teeth were equally divided The International Journal of Periodontics & Restorative Dentistry

4 57 Table 1 Supracrestal gingival tissue measurements in men (mm ± SD) Second premolars First molars Maxillary Mandibular Maxillary Mandibular Site Right Left Left Right Right Left Left Right DB 3.9 ± ± ± ± ± ± ± ± 0.59 CB 2.9 ± ± ± ± ± ± ± ± 0.50 MB 4.1 ± ± ± ± ± ± ± ± 0.50 CL 2.9 ± ± ± ± ± ± ± ± 0.45 DB = distobuccal; CB = center buccal; MB = mesiobuccal; CL = center lingual. Table 2 Supracrestal gingival tissue measurements in women (mm ± SD) Second premolars First molars Maxillary Mandibular Maxillary Mandibular Site Right Left Left Right Right Left Left Right DB 3.5 ± ± ± ± ± ± ± ± 0.65 CB 2.8 ± ± ± ± ± ± ± ± 0.45 MB 3.8 ± ± ± ± ± ± ± ± 0.50 CL 2.8 ± ± ± ± ± ± ± ± 0.61 DB = distobuccal; CB = center buccal; MB = mesiobuccal; CL = center lingual. between maxillary and mandibular, left and right, and second premolars and first molars. Probing was performed at four sites on each tooth (distobuccal [DB], center buccal [CB], mesiobuccal [MB], center lingual [CL]), for a total of 1,600 sites. The rationale for choosing posterior teeth was their high likelihood of receiving crown-lengthening procedures with ostectomy. The participants were probed at random by the same examiner. Contralateral data for each participant were collected on alternate days and registered on different forms by blinded students. Data were statistically analyzed by one-way analysis of variance (ANOVA) (SPSS version 13.0, SPSS Inc). Results Results showed that SGT measurements ranged from 1.0 to 6.0 mm (mean, 3.3 ± 0.8 mm). In men and women, the mean measurements were 3.4 ± 0.8 mm and 3.2 ± 0.8 mm, respectively. Contralateral SGT measurements showed no statistical difference when analyzed by one-way ANOVA (P =.096). Mean measurements and standard deviations for each tooth/site for men and women are shown in Tables 1 and 2, respectively. Note that the mean measurements at contralateral teeth in men were identical on the mandibular left and right second premolars, sites DB, MB, and CL; the maxillary right and left first molars, site CB; and the mandibular right and left first molars, site MB. In women, identical mean measurements were also found at the maxillary right and left first molars, site CL, and the mandibular right and left first molars, sites DB and CL. When SGT measurements were compared contralaterally in the same patient, the percentage of identical measurements for the second premolar ranged from 72% to 92% in men and 56% to 84% in women; for molars, it varied from 60% to 76% in men and 44% to 76% in women. Figure 3 shows the number of identical measurements (in percentage) at contralateral teeth/sites. Note that the highest percentage of identical measurements was observed in men on maxillary premolars at the CB site (92%). Volume 28, Number 1, 2008

5 Men Women Sites with identical measurements (%) DB = distal buccal CB = center buccal MB = mesial buccal CL = center lingual 0 DB CB MB CL DB CB MB CL DB CB MB CL DB CB MB CL Maxillary first molar Maxillary second premolar Mandibular first molar Mandibular second premolar Fig 3 SGT in men and women. Bars show the percentage of sites with the same measurement. Note that the highest number of identical measurements (92%) was observed in men on the central buccal site of the maxillary second premolars. Discussion The term biologic width, first mentioned by Cohen 2 in 1962 and based on the study of Gargiulo et al, 1 includes the junctional epithelium and the connective tissue fibers and has been widely discussed in the literature. The term supracrestal gingival tissue 3 has been suggested for the sum of the supracrestal fibers, the junctional epithelium, and the gingival sulcus. It has been stated that this entity occupies approximately at least 3.0 mm supracrestally. The first 1 mm occlusal to the alveolar crest is occupied by supracrestal fibers that insert into the cementum via the Sharpey fiber attachment. The next occlusal 1 mm of cementum is covered by the junctional epithelium. The depth of the sulcus is relative to the position of the tooth in the alveolar housing but is unlikely to be less than 1.0 mm in depth. The combined sum of the sulcus, junctional epithelium, and the supracrestal fibers has thus been estimated to be a minimum of 3.0 mm supracrestally. 20 However, this classical 3.0-mm measurement has been derived from necropsy specimens or empiric studies with no individualized data. 1,2,20 The present study evaluated the clinical SGT in healthy human periodontium by sulcular probing. Although sulcular probing has been mentioned in the literature since the 1950s, it was not until 1989 that Ursell 35 developed a study to evaluate this clinical measurement method. The author concluded that sulcular probing is a precise method to measure the bone level. In the absence of periodontal disease, sulcular probing, via the crevice to the crest of the alveolar bone, may be used to determine the dimension of the SGT at any specific site prior to crown-lengthening surgery. The International Journal of Periodontics & Restorative Dentistry

6 59 Nevertheless, there is a paucity of studies in the literature regarding sulcular probing as a method to identify the SGT values in individuals. The present results showed that the SGT measurement ranged from 1.0 to 6.0 mm (mean, 3.3 ± 0.8 mm). When SGT measurements were compared individually contralaterally, the mean percentage of identical measurements was 71.8%. The highest number of repetitions (92%) was observed for men at the maxillary second premolars at the CB site. The conventional 3.0-mm measurement was found in only 46.8% of 1,600 probed sites. Although the Gargiulo et al study 1 is a classic human study, it is relevant to mention that the authors studied 30 jaws, 287 teeth, and 325 sites in cadavers, with no gender classification and no individual or contralateral measurements. In addition, the histologic study included different stages of tooth eruption and differing relationships of the hard and soft tissues of the periodontium to the tooth surface. In the present study, 100 dental students, 400 teeth, and 1,600 sites were probed to perform contralateral comparisons of the SGT measurements in each individual. This rationale is based on the hypothesis that the SGT measurement is genetically predetermined. Therefore, any clinical procedure that involves the SGT should be individualized. This is exemplified by our results at the maxillary left second premolar in men, where the mean SGT measurements at the DB and MB sites were 4.1 and 4.2 mm, respectively. The standard suggested 3.0 mm bone removal during crown-lengthening procedures would thus be insufficient to house the new SGT components. In another example, the CB site on the mandibular right first molar in women showed a mean of 2.2 mm of SGT. In this case, then, the standard 3.0-mm bone resection to reestablish the SGT would be excessive. Several authors 9,11 14,17,21,22 have studied the relationship between the SGT and prosthetic tooth preparation endorsed by the measurements of Gargiulo et al. 1 It is empirically suggested that a sound tooth should be exposed from the alveolar crest in an amount varying from 2.5 to 5.25 mm. We understand that, once the preoperative amount of SGT present at a contralateral tooth/site in the same individual is known, it is easy to determine the extent of osseous resection that will be necessary for that individual to provide the appropriate accommodation for the regenerated SGT. In addition, it may be hypothesized that the amount of SGT formed postsurgically will be similar to the amount present prior to the surgery. However, controlled studies evaluating tooth types, biotypes, width of the keratinized gingiva, and healing aspects of crownlengthening procedures are needed. The rationales for intracrevicular restorative margin placement have included the enhancement of esthetics, removal of caries or faulty restorations, prevention of root sensitivity, and tooth preparation retention form. 22 Maynard and Wilson 22 have differentiated the terms intracrevicular restorative margin (those placed into and confined within the gingival crevice) and subgingival margin (those that extend beyond the gingival crevice into the junctional Volume 28, Number 1, 2008

7 60 epithelium and connective tissue). Thus, there has not been agreement as to the degree of restorative margin extension. Several investigations have suggested that the margin should be placed at the base of the gingival sulcus, 29,32, mm from the alveolar crest, 5,15,34 half the distance between the sulcus and the gingival margin, 31 slightly below the gingival margin, 26,27 at the crest of the gingival margin, 24,30 or extended 0.5 mm, to 1 mm, to 1.5 mm, 23 or 1.5 to 2.0 mm into the crevice. 22 However, there seems to be little scientific evidence to support some of these statements. In this study, because SGT measurements varied from 1.0 to 6.0 mm, it is assumed that 0.5 mm of minimal intrasulcular extension would violate a 1.0-mm SGT. On the other hand, a 6.0-mm SGT measurement describes an advantageous situation when the introduction of more than 0.5 mm into the sulcus would be needed to repair a dark root or any other esthetic problem. If the dimension of the SGT for a given situation is known, it is possible to reliably predict the final position of the gingival margin. The creeping of the SGT to its predetermined dimensions would ensure that the preparation margin ends up in an acceptable into the crevice location. Thus, the final preparation is extremely important and should respect the period needed for the SGT to heal. Conclusion Within the limitations of this study, the following conclusions can be drawn: 1. Contralateral SGT measurements prior to crown lengthening or restorative procedures may help determine the amount of bone removal or tooth preparation into the sulcus. 2. The standard 3.0 mm of bone removal for crown-lengthening procedures or 0.5 mm for tooth preparation into the sulcus should be reviewed. References 1. Gargiulo AW, Wentz FM, Orban B. Dimensions and relations of the dentogingival junction in human. J Periodontol 1961;32: Cohen DW. Periodontal preparation of the mouth for restorative dentistry. Presented at the Walter Reed Army Medical Center, Washington, June Smukler H, Chaibi M. Periodontal and dental considerations in clinical crown extension: A rational basis for treatment. Int J Periodontics Restorative Dent 1997;17: Parma-Benfenati S, Fugazzotto PA, Ruben MP. The effect of restorative margins on the post-surgical development and the nature of the periodontium. Int J Periodontics Restorative Dent 1985;5: Silvers JE, Johnson GK. Periodontal and restorative considerations for crown lengthening. Quintessence Int 1985;12: Ingber JS. Forced eruption: Part I. A method of treating isolated one- and two-wall infrabony osseous defects Rationale and case report. J Periodontol 1974;45: The International Journal of Periodontics & Restorative Dentistry

8 61 7. Ingber JS. Forced eruption: Part II. A method of treating nonrestorable teeth Periodontal and restorative considerations. J Periodontol 1976;47: Ingber JS, Rose LF, Coslet JG. The biologic width : A concept in periodontics and restorative dentistry. Alpha Omegan 1977;70: Lee EA. Aesthetic crown lengthening: Classification, biologic rationale, and treatment planning considerations. Pract Proced Aesthet Dent 2004;16: Rosenberg ES, Garber DA, Evian CI. Tooth lengthening procedures. Compend on Contin Educ Dent 1980;1: Baima RF. Extension of clinical crown length. J Prosthet Dent 1986;55: Block PL. Restorative margins and periodontal health: A new look at old perspective. J Prosthet Dent 1987;57: Carnevale G, Sterrantino SF, Di Febo G. Soft and hard tissue wound healing following tooth preparation to the alveolar crest. Int J Periodontics Restorative Dent 1983;3: Kaldahl WB, Becker CM, Wentz FM. Periodontal surgical preparation for specific problems in restorative dentistry. J Prosthet Dent 1984;51: Nevins M, Skurow HM. The intracrevicular restorative margin, the biologic width, and the maintenance of the gingival margin. Int J Periodontics Restorative Dent 1984;4: Newcomb GM. The relationship between the location of subgingival crown margins and gingival inflammation. J Periodontol 1974;45: Palomo F, Kopczyk RA. Rationale and methods for crown lengthening. J Am Dent Assoc 1978;96: Vacek JS, Gher ME, Assad DA, Richardson AC, Giambarresi LI. The dimensions of the human dentogingival junction. Int J Periodontics Restorative Dent 1994;14: Assif D, Pilo R, Marshak B. Restoring teeth following crown lengthening procedures. J Prosthet Dent 1991;65: Nevins M, Mellonig JT (eds). Periodontal Therapy: Clinical Approaches and Evidence of Success. Chicago: Quintessence, 1998: Wagenberg BD, Eskow RN, Langer B. Exposing adequate tooth structure for restorative dentistry. Int J Periodontics Restorative Dent 1989;9: Maynard JG, Wilson RDK. Physiologic dimensions of the periodontium significant to the restorative dentist. J Periodontol 1979;50: Fairley JM, Deubert LW. Preparation of a maxillary central incisor for porcelain jacket restoration. Br Dent J 1958;104: Pini CE. Co-report: Hygienic considerations in crown and bridge prothesis. Int Dent J 1958;8: Stein R, Glickman I. Prosthetic considerations essentials for gingival health. Dent Clin North Am 1960;4: Weinberg LA. Esthetics and the gingival in full coverage. J Prosthet Dent 1960; 10: Herlands R, Lucca J, Morris M. Forms, contours, and extensions of full coverage in occlusal reconstruction. Dent Clin North Am 1962;6: Minkler JS. Simplified full coverage preparations. Dent Clin North Am 1965;25: Wagman SS. Tissue management for full cast veneer crowns. J Prosthet Dent 1965;15: Marcum JS. The effect of crown marginal depth upon gingival tissue. J Prosthet Dent 1967;17: Tylman SD. The Theory and Practice of Crown and Fixed Partial Prosthodontics. St Louis: CV Mosby, 1970: Glickman I. Clinical Periodontology. Philadelphia: W. B. Saunders, 1972: Johnston JF, Philips RW, Dykema RW. Modern Practice in Crown and Bridge Prosthodontics. Philadelphia: Saunders, 1971: Fugazzotto PA. Periodontal restorative interrelationships: The isolated restoration. J Am Dent Assoc 1985;10: Ursell MJ. Relationships between alveolar bone levels measured at surgery, estimated by transgingival probing and clinical attachment level measurements. J Clin Periodontol 1989;16: Volume 28, Number 1, 2008