One of the six tools used in the Global Diagnosis system is esthetic crown lengthening surgery. This surgical procedure is specifically designed to treat one condition: altered passive eruption. Altered pas- sive eruption is a condition that was described by Coslet et al1 nearly 40 years ago. They differentiated patients with excess gingival coverage into four categories based on the position of the alveolar bone in relation to the cementoenamel junction (CEJ) and the mucogingival junction. However, the clinical treatment of these patients is the same2,3; therefore, the term altered passive eruption is used to describe all of the categories of excess gingival coverage of the anatomical crown. In order to diagnose a patient with altered passive eruption, two criteria must be met. First, the tooth must be short by measurement. The average length of the clinical crown of the normal maxil- lary central incisor is 10 to 11 mm, 4 so the teeth must be shorter than this. 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 with the smoothness of the adjacent enamel (Fig 4-1). 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 (Fig 4-2).
The prevalence of short clinical crowns due to gingival coverage was evaluated by Konikoff et al.5 The study population was a group of 200 teenagers who had recently had orthodontic appliances removed. They evaluated the width-to-height ratios of the central incisors and used 0.8 or less as nor- mal. In this population, they found that 66% had a width-to-height ratio greater than 0.8. This study suggests that a significant percentage of postorthodontic patients have short clinical crowns due to gingival coverage of the anatomical crown. They also did a 5-year follow-up on patients and found that if a patient has short clinical crowns prior to orthodontic treatment, there is a high probability that these teeth will continue to have short clinical crowns 5 years after completion of orthodontics.
One of the most common etiologies of the gummy smile, defined as 2 mm or more of gingival dis- play in full smile, is altered passive eruption. Tjan et al6 reported on the smile dynamics of a population in their second decade of life. He reported 2 mm or more of gingival display in 13% of females and 7% of males. It is fair to say that there are many teenage and adult patients with altered passive eruption who are not being diagnosed and treated.
In order to understand altered passive eruption, it is important to first understand the normal erup- tion process, which consists of two stages.7 The first is termed active eruption. As the crown of the tooth (ie, the central incisor) forms, it begins to erupt through the bone and soft tissue and grows down into the mouth. It continues to actively erupt until it occludes with the opposing tooth into a stable occlusal relationship. At this point, for all practical purposes, active eruption is complete. Growth of the maxilla and mandible will continue, but eruption of the tooth out of the alveolar process is complete. However, at the completion of the active eruption process, the clinical crown may only be 5 to 6 mm in length. At this time, the second stage of the eruption process—passive eruption—begins. Passive eruption is the normal apical migration of the gingival tissue up the anatomical crown until it gets to within approximately 1 to 2 mm of the CEJ. At this point, the tissue stabilizes, resulting in the normal clinical crown length of 10 to 11 mm.
In altered passive eruption, the tissue does not migrate to its correct position, 1 to 2 mm coronal to the CEJ. This results in excessive gingival coverage of the cervical enamel and a short clinical crown. Research has shown that the normal eruption process of the anterior teeth is essentially complete at approximately 15 to 16 years of age.8 It is at this age that esthetic crown lengthening surgery is gener- ally recommended. Figure 4-3 illustrates the natural course of the eruption process in a patient from age 7 to age 18 years. Note that there is no change in the length of the clinical crown from age 15 to age 18 years
Surgical Technique
Esthetic crown lengthening is a surgical procedure specifically designed to treat altered passive erup- tion. The traditional functional crown lengthening procedure, which is used to treat fractured teeth, deep caries, biologic width impingement, and inadequate clinical crown length for restoration, re- quires both facial and palatal flaps as well as excision of the interdental tissue. In contrast, in the esthet- ic crown lengthening procedure, only a facial flap is elevated, leaving the thinned interdental papillary tissue and palatal tissue intact.
The distal extent of the initial incision must be determined by evaluating the dynamic smile prior to anesthesia. The incision generally extends one tooth distal to the distal extent of the smile to include all of the maxillary teeth that are visible in the smile.
Surgical goals
There are three surgical goals with the esthetic crown lengthening procedure:
Initial incision
There are two different techniques for the initial incision.
Option 1: Internal bevel gingivectomy
The initial incision is an internal bevel gingivectomy, which removes a collar of crestal gingiva (Fig 4-4). The incision is a thinning incision made with the scalpel blade (15c) nearly parallel to the long axis of the tooth. This incision is difficult because the architecture of the scallop must be esthetically correct and symmetric with the adjacent teeth while at the same time thinning the new marginal tissue. The incision continues as a thinning incision across each papilla to the distal extent of the surgical site. The collar of tissue is removed. A full-thickness flap is then elevated, and the appropriate ostectomy is per- formed. The tissue is then replaced and sutured. This incision may be used in all esthetic crown length- ening procedures; however, it must be used when the presenting gingival levels are uneven (Fig 4-5). The internal bevel gingivectomy incision is used to level the gingiva prior to elevating the flap.
Option 2: Sulcular incision
When the sulcular incision is chosen, there is no removal of a collar of gingival tissue. The incision is made through the sulcus to the crest of alveolar bone (Figs 4-6a and 4-6b). The incision continues as a thinning incision across each papilla to the distal extent of the surgical site (Fig 4-6c). A full-thickness flap is elevated beyond the mucogingival junction, and the appropriate ostectomy is performed. The flap is then apically positioned to its new position and sutured. The sulcular incision may only be employed when the presenting gingival levels are even; it cannot be used as the initial incision with uneven gingival levels. However, once the gingiva is leveled with the internal bevel gingivectomy incisions, the sulcular incision may be used to complete the initial incision. The sulcular incision is an easier initial incision to perform than the internal bevel gingivectomy. Additionally, it has been the author’s experience (JWR) that the tissue heals more quickly and more beautifully knife-edged with the sulcular incision.
Alveolar recontouring
The alveolar crest is always too close to the CEJ in some areas and is commonly too thick. The goal is for the alveolar bone to be 2 mm apical to the CEJ from facial line angle to facial line angle. Generally, facial alveolar bone must also be removed to thin the buccal plate between the roots of the teeth (Fig 4-7). The bone must be recontoured, much like a denture is festooned. A large, 12-fluted, round car- bide finishing bur in a high-speed handpiece with water irrigation is used for the gross bone removal. This bur will aggressively remove bone and must be used with a light touch (Fig 4-8). It is preferable that the bur not touch the tooth root. Once the initial thinning of the bone has been accomplished, a Wedelstaedt chisel is used to remove the thinned bone over the root surface (Fig 4-9). The new alveolar crest should parallel the CEJ with one modification: A small amount of additional bone must be removed at the line angles. This will ensure a more rounded and pleasing gingival contour after healing. Once the correct bony contours are established with the Wedelstaedt chisel, the marginal al- veolar bone will be ledged and too thick. A less aggressive bullet-nosed diamond bur in a high-speed handpiece with water irrigation is used to recontour the marginal alveolar bone to a knife edge (Fig 4-10). 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 (Fig 4-11). Commonly, this evaluation will reveal the need for additional alveolar recontouring to create the desired symmetry.
Tissue recontouring
After the alveolar recontouring is complete, the flap is repositioned, and the relationship between the flap and the remaining interdental papillae is evaluated. Commonly, there is excess facial interdental papillary tissue that does not smoothly blend with the flap. A new 15c scalpel blade is used to thin and recontour the papillary tissue until a satisfactory blend with the flap is accomplished (Fig 4-12).
Suturing
The placement of the flap is critical prior to suturing. The new gingival crest must be placed 3 mm coronal to the new alveolar crest. A 5/0 polygalactic acid suture is used. The suture is a simple inter- rupted suture that goes from flap to papilla. The suture is placed in the facial surface of the papilla and does not need to engage the palatal tissue. Once the suturing is complete, the surgeon should sound the bone of the maxillary central incisor to ensure that the distance from the gingival crest to the alveolar crest is 3 mm. If not, this must be corrected before completion of the surgery. The final step after suturing is to perfect the tissue blend between the flap and the papilla. This can be accom- plished with a laser or an electrosurgery unit. Periodontal dressing is seldom needed with this surgical procedure. However, it may be useful when the surgery is performed with orthodontic appliances in place, because it is sometimes difficult to stabilize the flap in the correct position. In this circumstance, the orthodontic appliances can be used to maintain the periodontal dressing, which will stabilize the flap in the correct position.
Postoperative course
The postoperative course is usually uneventful with minimal discomfort. The patient is shown the sur- gical result with a mirror and then asked not to pull the lip up to look for the next week. It is important that the tissue remains stable in its new position, so the patient is advised to not activate the lip mus- cles during the first week with activities such as sucking through a straw or kissing. The patient is also advised to refrain from brushing the entire mouth for 3 days. The patient is given an antimicrobial rinse to gently swish two times per day. Gentle brushing of the mandibular arch may be started after 3 days. The patient returns for suture removal after 1 week, and at that time the dentist decides if the tissue is stable enough to allow the patient to start gentle brushing of the maxillary arch. Postoperative pain is almost always managed with over–the-counter nonsteroidal anti-inflammatory drugs. The patient generally only needs pain medication for 1 or 2 days after the surgery.
Case Presentations
Case 1
A 16-year-old girl presented with a chief complaint of short teeth and a gummy smile (Figs 4-13a to 4-13c). Her medical history was noncontributory. Her maxillary central incisors were 8.5 mm long, and the CEJs could not be detected in the sulcus; therefore, a diagnosis of altered passive eruption was made. The surgical procedure, as previously described, was accomplished with local anesthesia (Figs 4-13d to 4-13f). Six weeks postoperatively, the tissue was well healed in its new position (Figs 4-13g to 4-13i). Although it appears that an open gingival embrasure was created with the surgical procedure, it was actually present preoperatively. It is not obvious in the preoperative photograph because it is filled with dental plaque, but it can be seen in the intraoperative photograph.
Case 2
The prevalence of short clinical crowns due to gingival coverage was evaluated by Konikoff et al.5 The study population was a group of 200 teenagers who had recently had orthodontic appliances removed. They evaluated the width-to-height ratios of the central incisors and used 0.8 or less as nor- mal. In this population, they found that 66% had a width-to-height ratio greater than 0.8. This study suggests that a significant percentage of postorthodontic patients have short clinical crowns due to gingival coverage of the anatomical crown. They also did a 5-year follow-up on patients and found that if a patient has short clinical crowns prior to orthodontic treatment, there is a high probability that these teeth will continue to have short clinical crowns 5 years after completion of orthodontics.
One of the most common etiologies of the gummy smile, defined as 2 mm or more of gingival dis- play in full smile, is altered passive eruption. Tjan et al6 reported on the smile dynamics of a population in their second decade of life. He reported 2 mm or more of gingival display in 13% of females and 7% of males. It is fair to say that there are many teenage and adult patients with altered passive eruption who are not being diagnosed and treated.
In order to understand altered passive eruption, it is important to first understand the normal erup- tion process, which consists of two stages.7 The first is termed active eruption. As the crown of the tooth (ie, the central incisor) forms, it begins to erupt through the bone and soft tissue and grows down into the mouth. It continues to actively erupt until it occludes with the opposing tooth into a stable occlusal relationship. At this point, for all practical purposes, active eruption is complete. Growth of the maxilla and mandible will continue, but eruption of the tooth out of the alveolar process is complete. However, at the completion of the active eruption process, the clinical crown may only be 5 to 6 mm in length. At this time, the second stage of the eruption process—passive eruption—begins. Passive eruption is the normal apical migration of the gingival tissue up the anatomical crown until it gets to within approximately 1 to 2 mm of the CEJ. At this point, the tissue stabilizes, resulting in the normal clinical crown length of 10 to 11 mm.
In altered passive eruption, the tissue does not migrate to its correct position, 1 to 2 mm coronal to the CEJ. This results in excessive gingival coverage of the cervical enamel and a short clinical crown. Research has shown that the normal eruption process of the anterior teeth is essentially complete at approximately 15 to 16 years of age.8 It is at this age that esthetic crown lengthening surgery is gener- ally recommended. Figure 4-3 illustrates the natural course of the eruption process in a patient from age 7 to age 18 years. Note that there is no change in the length of the clinical crown from age 15 to age 18 years
Surgical Technique
Esthetic crown lengthening is a surgical procedure specifically designed to treat altered passive erup- tion. The traditional functional crown lengthening procedure, which is used to treat fractured teeth, deep caries, biologic width impingement, and inadequate clinical crown length for restoration, re- quires both facial and palatal flaps as well as excision of the interdental tissue. In contrast, in the esthet- ic crown lengthening procedure, only a facial flap is elevated, leaving the thinned interdental papillary tissue and palatal tissue intact.
The distal extent of the initial incision must be determined by evaluating the dynamic smile prior to anesthesia. The incision generally extends one tooth distal to the distal extent of the smile to include all of the maxillary teeth that are visible in the smile.
Surgical goals
There are three surgical goals with the esthetic crown lengthening procedure:
1. Thin and move the alveolar bone 2 mm apical to the CEJ from facial line angle to facial line angle.
2. Position the gingival crest 3 mm coronal to the new alveolar crest position.
3. Level the tissue at the new position.
Initial incision
There are two different techniques for the initial incision.
Option 1: Internal bevel gingivectomy
The initial incision is an internal bevel gingivectomy, which removes a collar of crestal gingiva (Fig 4-4). The incision is a thinning incision made with the scalpel blade (15c) nearly parallel to the long axis of the tooth. This incision is difficult because the architecture of the scallop must be esthetically correct and symmetric with the adjacent teeth while at the same time thinning the new marginal tissue. The incision continues as a thinning incision across each papilla to the distal extent of the surgical site. The collar of tissue is removed. A full-thickness flap is then elevated, and the appropriate ostectomy is per- formed. The tissue is then replaced and sutured. This incision may be used in all esthetic crown length- ening procedures; however, it must be used when the presenting gingival levels are uneven (Fig 4-5). The internal bevel gingivectomy incision is used to level the gingiva prior to elevating the flap.
Option 2: Sulcular incision
When the sulcular incision is chosen, there is no removal of a collar of gingival tissue. The incision is made through the sulcus to the crest of alveolar bone (Figs 4-6a and 4-6b). The incision continues as a thinning incision across each papilla to the distal extent of the surgical site (Fig 4-6c). A full-thickness flap is elevated beyond the mucogingival junction, and the appropriate ostectomy is performed. The flap is then apically positioned to its new position and sutured. The sulcular incision may only be employed when the presenting gingival levels are even; it cannot be used as the initial incision with uneven gingival levels. However, once the gingiva is leveled with the internal bevel gingivectomy incisions, the sulcular incision may be used to complete the initial incision. The sulcular incision is an easier initial incision to perform than the internal bevel gingivectomy. Additionally, it has been the author’s experience (JWR) that the tissue heals more quickly and more beautifully knife-edged with the sulcular incision.
Alveolar recontouring
The alveolar crest is always too close to the CEJ in some areas and is commonly too thick. The goal is for the alveolar bone to be 2 mm apical to the CEJ from facial line angle to facial line angle. Generally, facial alveolar bone must also be removed to thin the buccal plate between the roots of the teeth (Fig 4-7). The bone must be recontoured, much like a denture is festooned. A large, 12-fluted, round car- bide finishing bur in a high-speed handpiece with water irrigation is used for the gross bone removal. This bur will aggressively remove bone and must be used with a light touch (Fig 4-8). It is preferable that the bur not touch the tooth root. Once the initial thinning of the bone has been accomplished, a Wedelstaedt chisel is used to remove the thinned bone over the root surface (Fig 4-9). The new alveolar crest should parallel the CEJ with one modification: A small amount of additional bone must be removed at the line angles. This will ensure a more rounded and pleasing gingival contour after healing. Once the correct bony contours are established with the Wedelstaedt chisel, the marginal al- veolar bone will be ledged and too thick. A less aggressive bullet-nosed diamond bur in a high-speed handpiece with water irrigation is used to recontour the marginal alveolar bone to a knife edge (Fig 4-10). 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 (Fig 4-11). Commonly, this evaluation will reveal the need for additional alveolar recontouring to create the desired symmetry.
Tissue recontouring
After the alveolar recontouring is complete, the flap is repositioned, and the relationship between the flap and the remaining interdental papillae is evaluated. Commonly, there is excess facial interdental papillary tissue that does not smoothly blend with the flap. A new 15c scalpel blade is used to thin and recontour the papillary tissue until a satisfactory blend with the flap is accomplished (Fig 4-12).
Suturing
The placement of the flap is critical prior to suturing. The new gingival crest must be placed 3 mm coronal to the new alveolar crest. A 5/0 polygalactic acid suture is used. The suture is a simple inter- rupted suture that goes from flap to papilla. The suture is placed in the facial surface of the papilla and does not need to engage the palatal tissue. Once the suturing is complete, the surgeon should sound the bone of the maxillary central incisor to ensure that the distance from the gingival crest to the alveolar crest is 3 mm. If not, this must be corrected before completion of the surgery. The final step after suturing is to perfect the tissue blend between the flap and the papilla. This can be accom- plished with a laser or an electrosurgery unit. Periodontal dressing is seldom needed with this surgical procedure. However, it may be useful when the surgery is performed with orthodontic appliances in place, because it is sometimes difficult to stabilize the flap in the correct position. In this circumstance, the orthodontic appliances can be used to maintain the periodontal dressing, which will stabilize the flap in the correct position.
Postoperative course
The postoperative course is usually uneventful with minimal discomfort. The patient is shown the sur- gical result with a mirror and then asked not to pull the lip up to look for the next week. It is important that the tissue remains stable in its new position, so the patient is advised to not activate the lip mus- cles during the first week with activities such as sucking through a straw or kissing. The patient is also advised to refrain from brushing the entire mouth for 3 days. The patient is given an antimicrobial rinse to gently swish two times per day. Gentle brushing of the mandibular arch may be started after 3 days. The patient returns for suture removal after 1 week, and at that time the dentist decides if the tissue is stable enough to allow the patient to start gentle brushing of the maxillary arch. Postoperative pain is almost always managed with over–the-counter nonsteroidal anti-inflammatory drugs. The patient generally only needs pain medication for 1 or 2 days after the surgery.
Case Presentations
Case 1
A 16-year-old girl presented with a chief complaint of short teeth and a gummy smile (Figs 4-13a to 4-13c). Her medical history was noncontributory. Her maxillary central incisors were 8.5 mm long, and the CEJs could not be detected in the sulcus; therefore, a diagnosis of altered passive eruption was made. The surgical procedure, as previously described, was accomplished with local anesthesia (Figs 4-13d to 4-13f). Six weeks postoperatively, the tissue was well healed in its new position (Figs 4-13g to 4-13i). Although it appears that an open gingival embrasure was created with the surgical procedure, it was actually present preoperatively. It is not obvious in the preoperative photograph because it is filled with dental plaque, but it can be seen in the intraoperative photograph.
Case 2
A 35-year-old woman presented with a chief complaint of short teeth and a gummy smile (Figs 4-14a to 4-14c). Her medical history was noncontributory. Her maxillary central incisors were 5.5 mm long, and the CEJs could not be detected in the sulcus; therefore, a diagnosis of altered passive eruption was made (Figs 4-14d and 4-14e). The surgical procedure, as previously described, was accomplished with local anesthesia. There was a greater amount of alveolar bone (Fig 4-14f) than in Case 1, so more ag- gressive ostectomy and thinning of alveolar bone was required (Fig 4-14g). Six weeks postoperatively, the tissue was well healed in its new position (Figs 4-14h and 4-14i).
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