The perio-esthetic-restorative approach for anterior rehabilitation.

Ensuring clinical success begins with a careful discussion of treatment planning, comprehensively covering all variables in simple to complex cases. Procedures including the crown lengthening surgery, furcation treatment and mucogingival therapy and tooth restoration are essential treatment regimens requiring multifaceted expertise. The interplay of periodontics and restorative dentistry is present at many fronts including the response of the gingival tissue to the restorative preparations. Dental restorations and periodontal health are inseparably interrelated. The adaptation of the margins, the contours of the restoration, the proximal relationships and the surface smoothness have a critical biological impact on the gingiva and the supporting periodontal tissues. The different surgical procedures used for crown lengthening are gingivectomy/gingivoplasty, apically positioned flap with or without osseous resection and orthodontic extrusion. The paper presents crown lengthening of severely mutilated teeth to increase the clinical crown height for adequate restoration.

INTRODUCTION

Clinical crown of the tooth is the distance from the gingival margin to incisal edge or occlusal surface of the tooth. This distance should be increased when:

Margins of caries lesion are subgingivally

Margins of the tooth crown fractures are subgingivally

Tooth crown is too short for retention of restoration

There is an excess of the gingiva and anatomical tooth crown is opened partially.

A short clinical crown is defined as any tooth with less than 2 mm of sound, opposing parallel walls remaining after occlusal and axial reduction. The common causes of short clinical crown include caries, erosion, tooth malformation, fracture, attrition, excessive tooth reduction, eruption disharmony, exostosis, genetic variation, amelogenesis imperfecta and gummy smile.[1]

Average biologic width consists of the epithelial attachment (0.97 mm) plus connective tissue attachment (1.07 mm). This gives an average value of 2.04 mm. When this biologic width is violated by a restoration as a defense mechanism, inflammatory response accelerates bone loss to provide space for new connective tissue attachment, which results in increased pocket depth.[2] Therefore, impingement of a restoration on the biologic width will trigger loss of bone, connective tissue and epithelial attachment.[3]

A band of 2-3 mm of attached gingiva is preferable to maintain the restored tooth successfully. Since the resecting nature of this procedure, there is a risk of reducing the width of attached gingiva. For this reason, it is important to diagnose and to evaluate the attached gingiva when planning surgical crown lengthening procedure.[4]

The treatment modalities advised for short clinical crown are crown lengthening given by Cohen,[5] which includes gingivectomy, apically repositioned flap or apically repositioned flap with osseous recontouring. It can also be done by the procedure like forced tooth eruption.[6] A classification system for esthetic crown lengthening procedures has been proposed by Lee[7] as shown in Table 1.

Table 1

A classification system for esthetic crown lengthening procedures has been proposed by Lee[7]

This clinical report demonstrates the treatment sequence including the determination of the required length of crown and restoring the esthetics of the patient by undisplaced flap with osseous recontouring and subsequent placement of the crown.

CASE REPORT

A 28-year-old female patient who was referred from Department of Conservative Dentistry and Endodontics to Department of Periodontics, Subharti Dental College, Meerut to increase the length of the clinical crown in relation to maxillary right central incisor, maxillary right lateral incisor, maxillary left central incisor, maxillary left lateral incisor and maxillary left canine for placement of fixed prosthesis. A detailed medical and dental history was obtained from the patient. A thorough clinical examination was performed. It revealed severe loss of the tooth structure due to caries [Figure 1]. The teeth were endodontically restored. Radiographic examination showed Gutta Percha point in the apical one-third for the placement of post and core [Figure 2]. On probing, a generalized depth of 2 mm was observed [Figure 3] with 3-4 mm of attached gingiva. The teeth were not mobile. Maxillary and mandibular impressions were taken and diagnostic casts were obtained along with pre-operative intraoral photographs.

Figure 1

Pre-endo clinical photograph

Figure 2

Intraoral periapical post-endodontic treatment

Figure 3

Pre-operative (probing depth 2 mm)

An average of 2 mm of the clinical crown and 2 mm of biologic width was required to place the subgingival margins of the crown for which surgical crown lengthening was planned. According to classification by Lee[7] the present case falls under Type III category. A signed consent form was obtained from the patient.

Before planning for the surgery, complete plaque and calculus removal was done. After giving anesthesia, bone sounding was carried out to determine the amount of osseous reduction to be done. Undisplaced flap surgery with osseous recontouring was performed to increase the clinical crown length and to maintain the biologic width [Figure 4].

Figure 4

Intraoperative photograph

Maximum preservation of keratinized gingiva was performed. Ostectomy followed by osteoplasty was performed to obtain at least 4 mm of healthy tooth structure above the alveolar crest. The scalloping of the flap was performed anticipating the final underlying osseous contour. Flaps were sutured back. Routine post-operative instructions were given. The medications prescribed were, amoxicillin 500 mg tid for 5 days and paracetamol tid for 3 days.

Patient was recalled after 1 week for suture removal and after 1 month for re-evaluation [Figure 5]. 3 months post-surgery, the patient was referred to the Department of Conservative Dentistry and Endodontics for the fabrication of the crowns [Figure 6].

Figure 5

One month post-operative photograph

Figure 6

Crown placed 3 months post-operatively

DISCUSSION

An accurate diagnostic and interdisciplinary approach is necessary for obtaining improved, conservative and predictable results in esthetically compromised areas, like the anterior maxillary dentition. Periodontal health is of paramount importance for all teeth, both sound and restored. Thus, this procedure, as an adjunct to a restorative treatment, can produce predictable results while ensuring good esthetics and maintaining periodontal health.[8]

There are two aspects to the crown lengthening procedure: Esthetic and functional. In both cases, the surgical procedure is aimed at re-establishing the biological width, apically while exposing more tooth structure. Biological width is the sum of the junctional epithelium and supracrestal connective tissue attachment. The average space occupied by the sum of the junctional epithelium and the supracrestal connective tissue fibers was found to be 2.04 mm. Violation of biological width has been associated with gingival inflammation, discomfort, gingival recession, alveolar bone loss and pocket.[2]

To have a harmonious and successful long-term restoration, a 3 mm sound supracrestal tooth structure between bone and prosthetic margins, which allows for the reformation of the biological width plus sulcus depth is advocated. This can be achieved surgically by crown lengthening, orthodontically by forced tooth eruption or by a combination of both.[9]

The amount of tooth structure that is exposed above the osseous crest must be above 4 mm which is enough to provide for a stable dentogingival complex and biological width to permit proper tooth preparation and account for an adequate margin placement.[10] It was found that margins of fixed prosthesis significantly compromise the gingival health if placed below the gingival margin.[11]

After the procedure, it is customary to wait for 6-8 weeks before cementing the final restoration. This reduces chances of gingival recession after prosthetic crown insertion.[12] After a 2-3 weeks post-surgery period, temporary crowns may be used until there has been full healing and the gingival margin is in a stable position.[13]

Patients that require aesthetic crown lengthening however, frequently exhibit a high smile line. As a result, pressure is often placed on the restorative dentist to correct esthetic deficiencies as early as possible and maintain certain esthetic standards.

CONCLUSION

Proper treatment plan should be established before any clinical procedures. With the aim of it, a thorough examination including clinical examination, radiographic assessment and diagnostic wax up are essential. In this case report, visualization of the desired results has guaranteed the outstanding surgical and prosthodontic outcomes. In addition, the treatment modality was determined and every effort was exerted on fabricating properly designed fixed partial denture that distributes occlusal forces evenly.