Editorial Type:
Article Category: Case Report
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Online Publication Date: 02 Aug 2022

Esthetic Crown Lengthening Surgery – A 30-Year Retrospective and Lessons Learned

Page Range: 375 – 381
DOI: 10.2341/21-046-T
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SUMMARY

Esthetic crown lengthening (ECL) surgery has been available to our profession for more than 30 years. The objective of this article is to discuss the author’s evolution in the techniques associated with ECL surgery. Several technical modifications related to initial incision, ostectomy, and tissue placement will be discussed. In addition, reasons for tissue rebound will be discussed.

INTRODUCTION

Altered passive eruption is a condition that was described by Coslet and others1 more than 40 years ago. They differentiated these patients into four categories based on the position of the alveolar bone in relation to the cemento-enamel junction (CEJ) and the mucogingival junction. There is much discussion in the literature regarding etiology, diagnosis, and treatment, based on subcategories represented by different names, eg, altered active eruption, delayed passive eruption, and other types and subtypes.2 However, the clinical treatment of these patients is essentially the same—a full thickness flap with ostectomy. Because the surgeon has no control of the position and thickness of the underlying alveolar bone, a gingivecomy alone is seldom indicated as a treatment for this condition. The one indication for a gingivectomy will be discussed. Therefore, the term altered passive eruption will be used to describe all of the categories of excess gingival coverage of the anatomical crown.

To diagnose a patient with altered passive eruption,3 two criteria must be met. First, the tooth is short by measurement. The average length of the clinical crown of the normal maxillary central incisor is 10–11 mm. Second, the CEJ cannot be detected in the sulcus with the tip of an explorer. In a patient with a normal attachment apparatus, the CEJ can be detected in the sulcus due to its roughness, compared to the smoothness of the adjacent enamel. However, in the patient with altered passive eruption, the dentist can only feel smooth enamel all the way to the base of the sulcus. The CEJ cannot be felt because it is covered by the attachment apparatus. No anesthesia is required for this exam. The diagnosis can also be made with cone beam computed tomography (CBCT).4 Allen5,6 pioneered esthetic crown lengthening (ECL) surgery as the treatment for altered passive eruption.

The author has been performing ECL surgery for 30 years. Over these three decades, my view of this surgical procedure has evolved, based primarily on short- and long-term clinical outcomes. It is the purpose of this article to discuss successes, and more importantly, failures, some of which are controllable, and some which are not.

Regardless of the surgical technique, there are three treatment goals. Goal #1 is to thin and move the alveolar bone 2 mm apical to the cementoenamel junction (CEJ) from facial line angle to facial line angle. Some clinicians recommend moving the alveolar bone 3 mm apical to the CEJ to maximize the exposure of the anatomic crown. However, the goal of ECL is to move the bone to the position where nature should have moved it but didn’t. In the normal crest attachment, the average distance from CEJ to alveolar crest is 2 mm.7,8 Additionally, if the alveolar bone is moved 3 mm apical to the CEJ, there is greater likelihood that the patient may have an exposed root surface in the future. The root surfaces should not be scaled after the flap is elevated. Goal #2 is to position the gingival crest 3 mm coronal to the new alveolar crest position. This will result in the CEJ being 1 mm subgingival at the completion of surgery. Goal #3 is to level the tissue at the new position. It has been suggested that a surgical stent is helpful in guiding the ostectomy. This is true with functional crown lengthening surgery. However, in ECL surgery, the postoperative position of the osseous crest is based on the CEJ; therefore, an arbitrarily created surgical stent is not needed.

Some clinicians advocate the use of the laser for a closed ostectomy without flap elevation. McGuire and Scheyer9 evaluated this technique using an erbium-doped yttrium aluminum garnet (Er:YAG) laser and reported three consistent findings: 1) inadequate ostectomy and thinning of alveolar bone; 2) troughing of alveolar bone; and 3) charring of the root surfaces. For these reasons ECL surgery should be accomplished with an elevated flap.

I performed my first ECL surgical procedure in 1990. Initially, the classic approach of removing a collar of gingival tissue with an internal bevel gingivectomy was used (Figure 1). This initial incision can only be utilized when adequate keratinized tissue will remain after the gingivectomy. A horizontal incision across the midfacial of the papilla was used and the incision was extended to the distal of the second premolars. A full thickness flap was elevated to, or past, the mucogingival junction. Using a high-speed large, round 12-fluted carbide finishing bur, the bone was thinned over the root of each tooth without touching the root with the bur (Figure 2). The bone was also scalloped between the roots to create a normal festooned alveolus. The thinned bone over the root was removed with a 2-mm Wedelstaedt chisel, 2 mm apical to the CEJ from facial line angle to align with the same scallop as the CEJ (Figure 3). This resulted in a small but significant bony ledge where the bone approached the root. Therefore, the final step was to thin the bone to a knife edge with a bullet nosed diamond bur (Figures 4, 5). No attempt was made to create a distal zenith in the alveolar bone. The tissue was then replaced and sutured with simple interrupted sutures using 5/0 chromic gut. The goal of ECL was to uncover most of the anatomic crown, with the CEJ remaining 1 mm subgingival after healing. The sutures were removed two weeks postoperatively.

Figure 1.Figure 1.Figure 1.
Figure 1. Internal bevel gingivectomy.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 2.Figure 2.Figure 2.
Figure 2. Thinning and reshaping alveolar bone with large round 12-fluted carbide finishing bur.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 3.Figure 3.Figure 3.
Figure 3. Removing thinned alveolar bone adjacent to root surface with Wedelstaedt chisel.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 4.Figure 4.Figure 4.
Figure 4. Thinning of bony ledge created with the chisel, using a bullet nosed diamond bur.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 5.Figure 5.Figure 5.
Figure 5. Final ostectomy 2 mm apical to the cemento-enamel junction (CEJ).

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

I experienced two problems with this technique. First, the initial incision was difficult. It was imperative that the gingivectomy be an internal bevel incision so that the marginal tissue would be appropriately thinned. However, it was very difficult to get a uniform thickness of beveled marginal gingiva. In addition, it was essential that the incision over all of the anterior teeth was level and had the same arc. The second problem was that the marginal gingiva commonly healed with a rolled rather than knife edged margin.

For these reasons, I changed to the surgical technique that I have used for most of the last three decades. This technique uses a sulcular incision and apically positioned flap rather than an internal bevel gingivectomy. The initial incision is a sulcular incision (Figure 6) without the removal of a collar of tissue and a thinning incision across the papilla (Figure 7). The same technique for ostectomy is used as before. Finally, the flap is apically positioned so that the gingival crest is 3 mm coronal to the new alveolar crest and sutured in that position with simple interrupted sutures.

Figure 6.Figure 6.Figure 6.
Figure 6. Sulcular incision.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 7.Figure 7.Figure 7.
Figure 7. Thinning incision of the papilla.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

TECHNIQUE MODIFICATIONS

Over the years, several technique modifications have been implemented based on observation of my surgical outcomes: 1) Stopping the incision at the distal of the second premolars decreases access to the alveolar bone over the second premolar. This commonly results in inadequate ostectomy and a gingival step-down from canine to second premolar, which is unesthetic. Today, the incision is based on the distal extent of the smile, which is usually the mesial of the first molar. The incision should extend one tooth distal to the distal extent of the smile. Therefore, the incision should generally be carried to the mesial of the second molar. 2) The mid-papilla incision commonly left a scar. Currently, the incision is a thinning incision of the papilla with the 15c scalpel blade, essentially parallel to the long axis of the tooth (Figure 7). This results in an almost entire connective tissue bed over the papilla. 3) When the flap is apically positioned, it doesn’t blend with the remaining interdental papilla. Therefore, the interdental papilla must be reshaped by narrowing with a 15c scalpel blade to create a perfect blend (Figure 8). 4) When the arc of the ostectomy is parallel to the CEJ, the tissue commonly heals with a gingival contour that is too triangular. In order to prevent this, the ostectomy must be more parallel on the sides and moved slightly more interproximally (Figure 9). This is especially true on the mesial surface of the maxillary lateral incisor, where the ostectomy must be accentuated or the tissue will heal with a very triangular gingival arc (Figures 10, 11). 5) After the ostectomy is complete, the surgeon should stand in front of the patient to evaluate the horizontal symmetry of the newly created alveolar crests, and to ensure the required 2 mm from CEJ to alveolar crest is present. Commonly, this evaluation will reveal the need for additional alveolar recontouring to create the desired symmetry. 6) Chromic gut suture is still an acceptable material; however, 5/0 polyglycolic acid (PGA) suture is easier to use and looks better during the healing phase. The white color of the suture takes the color of blood and is difficult to see at a speaking distance. 7) After completion of the suturing, the surgeon must again stand in front of the patient to ensure that the tissue is level and that there is perfect gingival symmetry. Commonly there is a need for minor gingival recontouring and blending of the papillae and the flap, which is best accomplished with either a laser or electrosurgery. 8) Leaving the sutures for 14 days was found to serve no purpose and slowed healing. Today, the sutures are removed at 5–7 days postoperatively.

Figure 8.Figure 8.Figure 8.
Figure 8. Reshaping of remaining interproximal papilla to create smooth blend between papilla and flap.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 9.Figure 9.Figure 9.
Figure 9. Correct ostectomy which is more parallel on the sides and moved slightly more interproximally. Incorrect ostectomy which is parallel to the CEJ.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 10.Figure 10.Figure 10.
Figure 10. Inadequate ostectomy on mesial surfaces of both maxillary lateral incisors.

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Figure 11.Figure 11.Figure 11.
Figure 11. Clinical healing, demonstrating triangular shaped gingival crests on both maxillary lateral incisors due to inadequate ostectomy on the mesial surfaces.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

POSTOPERATIVE INSTRUCTIONS

The patient is advised not to do anything to activate the upper lip, eg, sucking through a straw, kissing, and/or pulling the lip up to look at the surgical site. For maxillary ECL surgery, the patient is instructed not to brush the entire mouth for four days. On day 5, the patient can start to brush the lower arch, but is instructed not to brush the upper arch for 2 weeks. The patient is given a bottle of antimicrobial rinse and instructed to gently swish and spit twice a day for two weeks.

TISSUE REBOUND

Any surgeon that has done ECL surgery has experienced tissue rebound in a small percentage of patients.10 There are four reasons for tissue rebound. The first is inadequate ostectomy. This can be either inadequate bone removal apico-coronally and mesio-distally (Figures 10, 11), or inadequate thinning of bone.

The second is bone regrowth over time. The alveolar bone does not regrow coronally; however, in some patients, the thickness of the bone will return, similar to the growth of an exostosis. As the bone becomes thicker, it can cause the gingival crest to migrate coronally. This complication is unpredictable, and there is no way to prevent it.

The third etiology of tissue rebound is orthodontic intrusion of the teeth after the ECL surgery (Figures 12, 13) This is a common occurrence and requires a second-stage surgery at the completion of orthodontics.

Figure 12.Figure 12.Figure 12.
Figure 12. Esthetic crown lengthening (ECL) surgery, 1 week postoperatively.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 13.Figure 13.Figure 13.
Figure 13. Tissue rebound after 6 months of orthodontic intrusion.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

The fourth etiology of tissue rebound is a specific type of supracrestal tissue attachment (biologic width). In 1961, Gargiulo and others7 published their now-classic data on attachment measurements. They reported the mean measurement of epithelial attachment plus connective tissue attachment was 2.04 mm. In 1977 Ingber and others11 described “biologic width” and credited Dr D Walter Cohen for coining the term. In 1994, Kois8 published his classic article on biologic width. He proposed three categories of biologic width based on the total dimension of attachment plus the sulcus depth. In order to operationally define biologic width, Kois suggests that the dentist must determine the total distance from the gingival crest to the alveolar crest. This procedure is termed bone sounding. The patient is anesthetized, and the periodontal probe is placed in the sulcus and pushed through the attachment apparatus until the tip of the probe engages alveolar bone. Based on this measurement from gingival crest to alveolar crest, he proposes three categories of supracrestal tissue attachment—normal crest, high crest, and low crest. By definition, normal crest means that the patient’s gingival crest is 3 mm from the alveolar bone midfacial and 3–4.5 mm at the line angles (Figure 14). This occurs approximately 85% of the time. In the high crest patient, the gingival crest is less than 3 mm from the alveolar crest, both mid-facially and at the line angles (Figure 15). This occurs approximately 2% of the time. In the low crest patient, the gingival crest is more than 3 mm from gingival crest to alveolar crest mid-facial and more than 4.5 mm at the line angles (Figure 16). This occurs approximately 13% of the time. In 2007, the author12 proposed two different categories of low crest, termed unstable low crest and stable low crest (Figure 17). The unstable low crest patient has a normal attachment apparatus (approximately 2 mm), but a greater than normal sulcus depth. The stable low crest patient has a normal sulcus depth, but a longer than normal attachment apparatus. In order to diagnose a low crest patient as stable or unstable, the dentist must perform gentle sulcus probing in addition to bone sounding. The sulcus probing must be done in a different position than the initial bone sounding.

Figure 14.Figure 14.Figure 14.
Figure 14. Normal crest-bone sounding 3 mm from gingival crest to alveolar crest midfacial and 3-4.5 mm from gingival crest to alveolar crest at line angle.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 15.Figure 15.Figure 15.
Figure 15. High crest—Bone sounding less than 3 mm from gingival crest to alveolar crest midfacial and less than 3 mm from gingival crest to alveolar crest at line angle.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 16.Figure 16.Figure 16.
Figure 16. Low Crest—Bone sounding greater than 3 mm from gingival crest to alveolar crest midfacial and greater than 4.5 mm from gingival crest to alveolar crest at line angle.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 17.Figure 17.Figure 17.
Figure 17. Unstable low crest. In this illustration, the sulcus depth is 3 mm and the attachment is 2 mm. Stable low crest. In this illustration, the sulcus is 1.5 mm and the attachment is 3.5 mm.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

These two different categories of patients respond very differently to both restorative and surgical procedures. The unstable low crest patient is susceptible to gingival recession, due to the deeper sulcus and unsupported gingival crest. Additionally, this is the only category of biologic width in which a gingivectomy can be successfully used. However, the stable low crest patient is much different, presenting with a normal sulcus depth but having a biologic requirement for a longer attachment apparatus. The stable low crest patient is not susceptible to gingival recession; however, this patient is susceptible to gingival rebound after ECL surgery because the ostectomy is inadequate to provide space for the longer attachment requirement. Therefore, it is necessary for the surgeon to determine the category of biologic width by bone sounding prior to ECL surgery. If the bone sounding reveals that the patient is low crest, then the surgeon must determine if the patient is stable or unstable by sulcus probing. If the patient is stable low crest, the surgeon must move the alveolar bone 3 mm apical to the CEJ rather than the traditional 2 mm used in all other biologic width categories (Figure 18). Without the additional ostectomy, there will be gingival rebound at the completion of ECL surgery.

Figure 18.Figure 18.Figure 18.
Figure 18. A low crest stable patient who required 3 mm of ostectomy to create adequate room for their supracrestal tissue attachment requirement.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

CASE REPORT

A 16-year-old female presented with altered passive eruption (Figures 19, 20), and ECL surgery was performed on the maxillary arch. A sulcular incision was extended from mesial of second molar to mesial of second molar. A full thickness flap was elevated past the mucogingival junction, revealing thick alveolar bone which was too close to the CEJs in many areas (Figure 21). The ostectomy was accomplished, resulting in a 2-mm distance from alveolar crest to CEJ (Figure 22), and the alveolar bone was significantly thinned in posterior quadrants (Figure 23). Closure was accomplished with 5/0 PGA suture (Figure 24). Postoperative healing was uneventful, with a significant improvement in the esthetics of her smile (Figures 25, 26, 27). Seven years after the initial ECL surgery, she returned with a complaint that there had been some tissue rebound in the lateral incisors and the posterior quadrants (Figure 28). A second ECL surgery was accomplished, revealing that the alveolar bone had become significantly thicker adjacent to the lateral incisors and in the posterior quadrants (Figure 29). The alveolar bone was thinned as it had been seven years earlier (Fig 23). Again, the healing was uneventful.

Figures 19, 20.Figures 19, 20.Figures 19, 20.
Figures 19, 20. Preoperative photographs.

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Figure 21.Figure 21.Figure 21.
Figure 21. Pre-ostectomy.

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Figures 22, 23.Figures 22, 23.Figures 22, 23.
Figures 22, 23. Post-ostectomy.

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Figure 24.Figure 24.Figure 24.
Figure 24. Postoperative after suturing.

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Figures 25, 26, 27.Figures 25, 26, 27.Figures 25, 26, 27.
Figures 25, 26, 27. Six weeks postoperatively. Note that the open gingival embrasure between the maxillary central incisors was already present in the surgical photographs.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

Figure 28.Figure 28.Figure 28.
Figure 28. 7-year post-operative photograph demonstrating gingival rebound in maxillary lateral incisors and posterior quadrants.

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Figure 29.Figure 29.Figure 29.
Figure 29. Second ECL surgery done at 7 years, demonstrating regrowth and thickness of alveolar bone.

Citation: Operative Dentistry 47, 4; 10.2341/21-046-T

CONCLUSION

As with all dental procedures, there are commonly several treatment techniques available to the clinician. This is certainly true for the treatment of altered passive eruption. It has been the purpose of this article to provide the evolution of my experience with ECL surgery.

Acknowledgments

I would like to acknowledge the three periodontists who have greatly influenced my understanding of periodontal surgery, Dr Alfred Lopez, Dr Eric Rindler, and Dr Pat Allen. I would like to thank Andrew Robbins for the illustrations.

This material was presented by the author at the 2018 annual meeting of the Academy of Operative Dentistry.

REFERENCES

  • 1.
    Coslet JG, Vanarsdall R, & WeisgoldA( 1977) Diagnosis and classification of delayed passive eruption of the dentogingival junction in the adultAlpha Omegan70(
    3
    ) 24– 28.
  • 2.
    Mele M, Felice F, Sharma P, Mazzotti C, Bellone P, & ZuchelliG( 2018) Esthetic treatment of altered passive eruptionPeriodontology 200077(
    1
    ) 65– 83.
  • 3.
    Robbins JW ( 1999) Differential diagnosis and treatment of excessive gingival displayPractical Periodontics and Aesthetic Dentistry11(
    2
    ) 265– 272.
  • 4.
    Batista EL Jr, Moreira CC, Batista FC, de Oliveira RR, & PereiraKKY( 2012) Altered passive eruption diagnosis and treatment: A cone beam computed tomography-based reappraisal of the conditionJournal of Clinical Periodontology39(
    11
    ) 1089– 1096.
  • 5.
    Allen EP ( 1988) Use of mucogingival surgical procedures to enhance estheticsDental Clinics of North America32(
    2
    ) 307– 330.
  • 6.
    Allen EP ( 1993) Surgical crown lengthening for function and estheticsDental Clinics of North America37(
    2
    ) 163– 179.
  • 7.
    Garguilo A, Wentz FM, & OrbanB( 1961) Dimensions and relations of the dentogingival junction in humansJournal of Periodontology32(
    3
    ) 261– 267.
  • 8.
    Kois JC ( 1994) Altering gingival levels: The restorative connection, Part 1: Biologic variablesJournal of Esthetic Dentistry6(
    1
    ) 3– 9.
  • 9.
    McGuire MK & ScheyerT( 2011) Laser assisted flapless crown lengthening: A case seriesInternational Journal of Periodontics and Restorative Dentistry31(
    4
    ) 357– 364.
  • 10.
    Deas DD, Moritz AJ, McDonnell HT, Powell CA, & MealeyBL( 2004) Osseous surgery for crown lengthening: A 6-month clinical studyJournal of Periodontology75(
    9
    ) 1288– 1294.
  • 11.
    Ingber JS, Rose LF, & CosletJG( 1977) The “biologic width”- A concept in periodontics and restorative dentistryAlpha Omegan7062– 65.
  • 12.
    Robbins JW ( 2007) Tissue management in restorative dentistryFunctional Esthetics and Restorative Dentistry1(
    3
    ) 2– 5.
    Conflict of Interest The author has no financial interest in any of the companies or products mentioned in this article.
Copyright: 2022
Figure 1.
Figure 1.

Internal bevel gingivectomy.

Figure 2.
Figure 2.

Thinning and reshaping alveolar bone with large round 12-fluted carbide finishing bur.

Figure 3.
Figure 3.

Removing thinned alveolar bone adjacent to root surface with Wedelstaedt chisel.

Figure 4.
Figure 4.

Thinning of bony ledge created with the chisel, using a bullet nosed diamond bur.

Figure 5.
Figure 5.

Final ostectomy 2 mm apical to the cemento-enamel junction (CEJ).

Figure 6.
Figure 6.

Sulcular incision.

Figure 7.
Figure 7.

Thinning incision of the papilla.

Figure 8.
Figure 8.

Reshaping of remaining interproximal papilla to create smooth blend between papilla and flap.

Figure 9.
Figure 9.

Correct ostectomy which is more parallel on the sides and moved slightly more interproximally. Incorrect ostectomy which is parallel to the CEJ.

Figure 10.
Figure 10.

Inadequate ostectomy on mesial surfaces of both maxillary lateral incisors.

Figure 11.
Figure 11.

Clinical healing, demonstrating triangular shaped gingival crests on both maxillary lateral incisors due to inadequate ostectomy on the mesial surfaces.

Figure 12.
Figure 12.

Esthetic crown lengthening (ECL) surgery, 1 week postoperatively.

Figure 13.
Figure 13.

Tissue rebound after 6 months of orthodontic intrusion.

Figure 14.
Figure 14.

Normal crest-bone sounding 3 mm from gingival crest to alveolar crest midfacial and 3-4.5 mm from gingival crest to alveolar crest at line angle.

Figure 15.
Figure 15.

High crest—Bone sounding less than 3 mm from gingival crest to alveolar crest midfacial and less than 3 mm from gingival crest to alveolar crest at line angle.

Figure 16.
Figure 16.

Low Crest—Bone sounding greater than 3 mm from gingival crest to alveolar crest midfacial and greater than 4.5 mm from gingival crest to alveolar crest at line angle.

Figure 17.
Figure 17.

Unstable low crest. In this illustration, the sulcus depth is 3 mm and the attachment is 2 mm. Stable low crest. In this illustration, the sulcus is 1.5 mm and the attachment is 3.5 mm.

Figure 18.
Figure 18.

A low crest stable patient who required 3 mm of ostectomy to create adequate room for their supracrestal tissue attachment requirement.

Figures 19, 20.
Figures 19, 20.

Preoperative photographs.

Figure 21.
Figure 21.

Pre-ostectomy.

Figures 22, 23.
Figures 22, 23.

Post-ostectomy.

Figure 24.
Figure 24.

Postoperative after suturing.

Figures 25, 26, 27.
Figures 25, 26, 27.

Six weeks postoperatively. Note that the open gingival embrasure between the maxillary central incisors was already present in the surgical photographs.

Figure 28.
Figure 28.

7-year post-operative photograph demonstrating gingival rebound in maxillary lateral incisors and posterior quadrants.

Figure 29.
Figure 29.

Second ECL surgery done at 7 years, demonstrating regrowth and thickness of alveolar bone.

Contributor Notes

*Corresponding author: 1902 Far Niente, San Antonio, Texas, 78258; e-mail: robbinsdds@aol.com

Clinical Relevance

Esthetic crown lengthening surgery is the treatment for altered passive eruption.

Accepted: 19 Jun 2021