|Year : 2018 | Volume
| Issue : 3 | Page : 132-136
Crown lengthening surgery: A periodontal makeup for anterior esthetic restoration
Department of Periodontics, Government Dental College, Thrissur, Kerala, India
|Date of Web Publication||20-Nov-2018|
Department of Periodontics, Government Dental College, Thrissur, Kerala
Source of Support: None, Conflict of Interest: None
| Abstract|| |
With the increasing popularity of esthetic dentistry, an understanding of the therapeutic modalities brought about by an interdisciplinary approach has developed. As a result, crown lengthening procedures have become an integral component of the esthetic armamentarium and are utilized with increasing frequency to enhance the appearance and retention of restorations placed within the esthetic zone. The present case is managed with an internal bevel gingivectomy together with bone recontouring without compromising tooth support and esthetics.
Keywords: Anterior restoration, crown lengthening, esthetic restoration, periodontal surgery
|How to cite this article:|
Anoop S. Crown lengthening surgery: A periodontal makeup for anterior esthetic restoration. J Interdiscip Dentistry 2018;8:132-6
| Clinical Relevance to Interdisciplinary Dentistry|| |
In our clinical practice we are routinely encountering cases like subgingival caries or extensive caries that shortens the tooth, fractures, and short clinical crowns. For restoring such cases it is often necessary to expose more tooth structure to get adequate retention. While performing a crown lengthening surgery we often miss to maintain adequate biologic width for periodontal health which will later lead to periodontal complications. If we are not giving any consideration to the periodontium; the restoration will be a failure despite how much esthetic it is.
| Introduction|| |
Crown lengthening is a surgical procedure designed to increase the extent of supragingival tooth structure for restorative or esthetic purposes by apically positioning the gingival margin, removing supporting bone or both. Indications for crown lengthening include teeth with subgingival caries or extensive caries that shortens the tooth, fractures, and short clinical crowns caused by incomplete exposure of the anatomic crowns. Several techniques such as gingivectomy, undisplaced flap with or without osseous surgery, apically repositioned flap with or without resective osseous surgery, and orthodontic forced eruption with or without fibrotomy have been proposed for clinical crown lengthening. The selection of one technique over another depends on several patient-related factors such as esthetics, clinical crown to root ratio, root proximity, root morphology, furcation location, individual tooth position, collective tooth position, and the ability to restore the teeth. With the increasing popularity of esthetic dentistry, an understanding of the therapeutic modalities brought about by an interdisciplinary approach has developed. As a result, crown lengthening procedures have become an integral component of the esthetic armamentarium and are utilized with increasing frequency to enhance the appearance and retention of restorations placed within the esthetic zone.
| Case Report|| |
A 45-year-old female reported to our department requesting “better-looking upper front teeth.” Her medical history was noncontributory, and she denied a history of smoking or alcohol consumption. Extraoral examination revealed no significant findings with normal lip line and minimal gingival display while smiling. Dental examination revealed that her 11 and 21 had been treated endodontically and there was extensive loss of clinical crown due to dental caries. Periodontal examination revealed good oral hygiene with minimal plaque and calculus deposits. The gingiva was pink and firm, and the papillae were intact. Clinical examination revealed shallow probing depths of 2 mm, no mobility, and 5 mm of keratinized attached gingiva. Radiographic examination of 11 and 21 shows overextended root canal filling with minimal interdental bone loss and root was found to be wide with adequate length [Figure 1]. The restorative treatment plan for the patient involved re-endodontic treatment and porcelain-fused-to-metal crowns for teeth 11 and 21. After discussion with the restorative dentist, crown lengthening was recommended to increase the extent of supragingival tooth structure and to allow a healthy, optimal relationship between the restoration and the periodontium. Patient had given two options; whether to go for a surgical correction or orthodontic extrusion. Orthodontic extrusion was seeming to be ideal in this case because any surgical correction will lead to gingival margin discrepancy between adjacent teeth. Patient was informed thoroughly the pros and cons of surgical technique, and because of lack of time, she opted for surgical correction.
|Figure 1: Radiograph showing overextended root canal filling with minimal interdental bone loss and wide root with adequate length|
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After giving adequate anesthesia, transgingival probing was done [Figure 2] around the intended tooth and found that 3 mm of soft tissue present above the alveolar crest. The level of incision is marked by placing bleeding spots using a pointed instrument [Figure 3]. Using a no. 15 Bard-Parker blade, the initial internal bevel incision was performed 3 mm above the gingival margin so as to achieve the ideal contour both on labial [Figure 4] and palatal aspect [Figure 5]. Note that sufficient amount of attached gingiva (5 mm) was present to give a remaining 2 mm around the restoration; otherwise, we have to go for an apically repositioned flap. Then a mucoperiosteal flap was raised. Osseous resection was performed using low speed handpiece and carbide bur under copious saline irrigation to maintain the biologic width (BW) [Figure 6] and [Figure 7]. The flap was repositioned and sutured [Figure 8] and [Figure 9]. Chlorhexidine rinse 0.2% bid was prescribed for 2 weeks, and the patient was given appropriate postoperative instructions.
|Figure 2: Transgingival probing showing 3 mm of soft tissue present above the alveolar crest|
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|Figure 3: Level of incision is marked by placing bleeding spots using a pointed instrument|
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Immediately after surgery, a temporary buildup of crown with composite has been done to maintain the gingival contour during healing [Figure 10]. Care was taken to ensure that the margins of the temporary crown were smooth and closely adapted to ensure gingival health. Custom-made post and core placed after 1 month [Figure 11]. Final insertion of the porcelain-fused metal crowns with subgingival margin was performed 2 months after the crown-lengthening surgery [Figure 12]. [Figure 13] shows patient's extraoral view after final restoration.
|Figure 10: Temporary composite buildup done immediately after crown lengthening procedure|
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| Discussion|| |
Crown lengthening treatment is based on two principles: establishment of BW and maintenance of adequate keratinized gingiva (KG) around the tooth. The BW is defined as the dimension of soft tissue that is attached to the portion of the tooth coronal to the alveolar bone crest. Studies show that a minimum of 3 mm of space between restorative margins and alveolar bone would be adequate for periodontal health, allowing for 2 mm of BW space and 1 mm for sulcus depth. Whenever possible, an adequate width of KG (≥2 mm) should be maintained around a tooth for gingival health. According to Nevins and Skurow, when subgingival margins are indicated, the restorative dentist must not disrupt the junctional epithelium or connective tissue apparatus during preparation and impression taking. They recommended limiting subgingival margin extension to 0.5–1.0 mm because it is impossible for the clinician to detect where the sulcular epithelium ends and the junctional epithelium begins. When the restoration margin is placed too far below the gingival tissue crest, it impinges on the gingival attachment apparatus and creates a violation of BW. Two different responses can be observed from the involved gingival tissues. One possibility is that bone loss of an unpredictable nature and gingival tissue recession occur as the body attempts to recreate room between the alveolar bone and the margin to allow space for tissue reattachment. This is more likely to occur in areas where the alveolar bone surrounding the tooth is very thin. Trauma from restorative procedures can play a major role in causing this fragile tissue to recede. The other possibility is that the bone level appears to remain unchanged, but gingival inflammation develops and persists.
In this case, internal bevel gingivectomy was taken as the treatment of choice, to maintain the periodontal health and postoperative esthetics of the patient. An internal bevel incision can thin down the gingival margin to a knife edge contour while preserving the maximum amount of attached gingiva. At the same time, it gives maximum comfort to the patient rather than external bevel gingivectomy because of open wound in latter.
Anatomical considerations need to be taken into account when a patient is being assessed for crown lengthening. They are length and shape of root, furcation position, lip line (at rest and smiling), width of interdental bone, local soft/hard tissue anatomy, and muscle insertions and amount of attached gingival tissue. There should be favorable crown: root ratio after treatment, as well as adequate tooth tissue to allow the accommodation of the restoration. In the present case after completion of treatment crown, root ratio remained adequate. If the tooth narrows considerably apically, there may be a risk of pulp exposure during preparation or risk of over contouring the restoration owing to insufficient space leading to unesthetic appearance. If the furcation is exposed during the bone removal, an area of plaque retention, which may lead to more bone loss, may occur. It has been demonstrated that there should be at least 4 mm from the furcation to the crestal bone preoperatively to reduce the risk of furcation exposure. If the roots are close together, there may be very little interdental bone, which may make it impossible to use an instrument in between the teeth for bone removal without risking damaging the roots. If the bone is not removed from the interproximal area, then it may be difficult to reposition the soft tissues, and there will be a reduction in the length that is gained, thereby compromising the retention of a restoration.
The position of the lip on smiling is very important as it will determine the amount of tooth and gingiva on display affecting the final esthetic outcome. If only one tooth needs treatment and there is a higher lip line, then the gingival discrepancy will be seen and the resultant esthetics poor. Other soft-tissue considerations are the muscle insertions, as a high muscle insertion may affect the apical repositioning of the flap. This is also true if there is a shallow vestibular sulcus or a high external oblique ridge, as it may limit the position of the flap.
In regions of the mouth where esthetics is important, wound healing after crown lengthening surgery must be allowed to proceed to completion if optimal results are to be achieved. After crown lengthening surgery, the periodontium continues to remodel and mature. Brägger et al. reported that gingival recession can occur between 6 weeks and 6 months after the surgery. Hence, if restorations are planned, recessions must be closely observed during the healing phase. Temporary crowns should be retained until the wounds are completely healed (possibly up to 6 months), after which final crown preparation and insertion can be done. If these guidelines are followed, gingival recession can be minimized. In this case, we have delivered the permanent restoration within 2 months and follow-up shows no recession at all.
Although not an absolute contraindication for periodontal surgery, cigarette smoking can impair wound healing and is detrimental to the success of the surgery. Other factors such as patient compliance, systemic factors, oral hygiene, and history of periodontal disease can also influence surgical outcome. The dentist should carefully consider these key factors in preparation for treatment in esthetically demanding areas.
The health of the periodontal tissues is dependent on properly designed restorative materials. Overhanging restorations and open interproximal contacts should be corrected during the disease control phase of periodontal therapy. Subgingival margin placement is often unavoidable, but care must be taken to involve as little of the sulcus as possible. Evidence suggests that even minimal encroachment on the subgingival tissue can lead to detrimental effects on the periodontium. If restorative margins need to be placed near the alveolar crest, crown lengthening surgery or orthodontic extrusion should be considered to provide adequate tooth structure while simultaneously assuring the integrity of the BW. Although individual variations exist in the soft-tissue attachment around teeth, there is general agreement that a minimum of 3 mm should exist from the restorative margin to the alveolar bone, allowing for 2 mm of BW space and 1 mm for sulcus depth.
Crown lengthening is a viable procedure that enables to restore teeth having a short clinical crown, extensive subgingival caries, and subgingival tooth fractures at dentogingival junction. When performed in ideal clinical conditions, crown lengthening gives satisfactory results both from a functional as well as esthetic point of view.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
The author thanks Dr. Roopa (Department of Conservative and Endodontics, PMS College of Dental Science and Research, Kerala, India) for endodontic treatment followed by post and core buildup and crown.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8], [Figure 9], [Figure 10], [Figure 11], [Figure 12], [Figure 13]