Shaping in Periodontal Therapy

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© Springer Nature Switzerland AG 2020

S. Nares (ed.)Advances in Periodontal Surgerydoi.org/10.1007/978-3-030-12310-9_4

4. Biologic Shaping in Periodontal Therapy

Danny Melker1, Alan Rosenfeld2   and Salvador Nares2  
(1)

Private Practice Limited to Periodontics, Clearwater, FL, USA
(2)

Department of Periodontics, University of Illinois at Chicago, College Dentistry, Chicago, IL, USA
 
 
Alan Rosenfeld
 
Salvador Nares (Corresponding author)
Keywords

Biologic shapingCrown lengtheningFurcationsBiologic width

4.1 Introduction

Periodontal surgery involves modification of hard and/or soft tissues to achieve a therapeutic goal. These goals include treatment of periodontal defects, including furcation involvement of molars, and crown lengthening procedures to facilitate restoration of a tooth or teeth. Traditionally, resective and regenerative techniques focus on osseous structures with little attention given to modification of tooth surface. Unfortunately, this could lead to excessive removal of the bone and/or creation of an environment that is not cleansable and biologically incompatible. Further, regenerative techniques can yield unpredictable results in furcation lesions thus predisposing molars to further attachment loss. Biologic shaping is intended to create a cleansable, biologically compatible root surface that is manageable by both patients and dentists/hygienists. Here modification of tooth surface is the primary focus with removal of the bone performed only when absolutely necessary to create a biocompatible environment. This chapter will focus on biologic shaping during the course of periodontal therapy.

4.2 Indications and Rationale for Biologic Shaping

Biologic shaping was first reported by Melker and Richardson in 2001 and described for esthetic dentistry in 2003 [1, 2]. It combines periodontic and restorative phases of dentistry and aims to facilitate home care by patients using simple hygiene aids such as floss and a toothbrush, as well as facilitate professional maintenance by hygienists to remove plaque and calculus. It also creates biologically compatible dimensions necessary for the restoration of a tooth without infringement on biologic width. Further, biologic shaping removes tooth-derived risk factors such as developmental grooves, enamel projections, and concavities. This is particularly important if a developmental groove, concavity, or enamel projection is in close proximity to an existing crown margin resulting in a void or retainment of cement in the groove (Fig. 4.1). This can create an unmanageable situation and increases risk of further attachment loss. Therefore, the ideal therapy will involve modification of tooth structure to eliminate these anatomical discrepancies and create a new restorative margin that is supragingival to the previous margin. The point being that biologic shaping limits the unnecessary removal of bone and creates a biocompatible environment.

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Fig. 4.1

Removal of developmental groove. (a) Developmental groove present on the right central incisor illustrating the problem when a margin finishes in a developmental groove (black arrow). There is a lack of adequate seal, and bonding material is located in the groove causing severe inflammation. (b) Removal of the developmental groove to allow for maintenance of the area (white arrow)

Biologic shaping is an alternative to conventional crown lengthening surgery [35]. Crown lengthening utilizes the margins of an existing restoration or the cementoenamel junction (CEJ) of a non-restored tooth to gauge the amount of ostectomy necessary to reestablish the biologic width (see Chap. 12 by Karateew et al. in this volume). Creating proper space ensures that a new margin will not impinge upon the attachment apparatus. This creates challenges in the furcation as removal of the bone in this region further compromises the tooth by creating an environment that is not cleansable for both the patient and the hygienist (Fig. 4.2). Thus, it is critical to preserve as much bone in the furcation area as possible. Therefore, rather than removing the bone away from the planned restorative margin, biologic shaping moves the restorative margin away from the bone, minimizing the amount by which the crown must be lengthened to establish biologic width. Table 4.1 lists the rationale for biologic shaping.

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Fig. 4.2

This patient was referred for correction of biologic width invasion. Prior treatment involved removal of existing restorations and decay and placement of cores and provisionals. (a) Provisionals removed. Note Durelon cement still present on the teeth. Antimicrobial effects of this cement are protective. (b) Reflection of a full thickness flap followed by a partial thickness dissection apical to the mucogingival junction. (c) Of critical importance is the location of the existing margin approximating the furcation. In essence there is no space for the biologic width. (d) After biologic shaping 100% of the tooth structure is perfectly smooth from the bone to the occlusal surfaces. Note that there is absolutely no margin present after biologic shaping. Critical is the actual location of the bone in the furcation. Removal of furcation results in coronal movement of the bone (arrow). No matter how much bone is removed, space for the biologic width cannot be achieved. By removing the previous margin and allowing a new biologic width to establish, the new margin can be placed coronal to the gingival collar. (e) The flap is sutured with 5–0 chromic gut just coronal to the bone. Primary closure helps to decrease postoperative discomfort. (f) The day of impressions. A chamfer margin is placed with a 0.3 mm thickness and placed just coronal to the gingival collar (arrow). Note the large amount of tooth structure remaining. (g) Final restorations cemented. All margins are supragingival. The furcation on #3 is perfectly contoured to follow the shape of the underlying tooth structure. The barreling in of the furcation is extended to the occlusal surface. The material for these restorations is Feldspathic porcelain. This case has now passed the 15-year period of stability and function. Restorations by Dr. William Strupp Jr

Table 4.1

Rationale for biologic shaping [5]

1.

Replacing or supplementing the current indications for clinical crown lengthening

2.

Minimizing osteotomy

3.

Facilitating supragingival or just slightly intrasulcular margins (when there is a dark substructure) to preserve the biologic width

4.

Eliminating developmental margins

5.

Eliminating previous subgingival restorative margins

6.

Reducing or eliminating furcation anatomy, thus facilitating margin placement

7.

Allowing supragingival or intrasulcular impression techniques

8.

Removing all CEJs

When treating combined periodontal and restorative cases, the periodontist must facilitate creation of a final margin (supragingival or just into the sulcus), improve tissue health to facilitate an accurate impression, and provide an abundance of dense connective tissue for augmentation of keratinized gingiva to protect the underlying periodontal support (Fig. 4.3). The dense connective tissue is essential for taking accurate impressions and cementing final restorations as there is greater probability of chronic inflammation if the restorative margin approximates mucosa [4]. This is discussed in greater detail in the Chaps. 9 and 10 and by Zadeh et al. and Chambrone et al., in this volume. For esthetic surgical procedures, the periodontist must provide ideal clinical anterior crown length to aid the restorative dentist in providing the highest level of esthetic treatment. The periodontist also must make every attempt to avoid black triangles as a result of periodontal surgery and support the restorative dentist by motivating patients to accept the comprehensive treatment plan.

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Fig. 4.3

(a) Case with three teeth requiring new restorations with chronic inflammation present on the first premolar (white arrow). (b) Restorations removed and decay excavated. (c) Core buildup (DenMat (Lompoc, CA, USA) enamel shade core paste) adds restorative volume to the teeth and helps determine placement of the final restorative margins. Connective tissue graft in place on the first premolar (black arrow). (d) Final restorations fabricated with Feldspathic porcelain with margins placed supragingival. Healing of the connective tissue graft provides a thick band of keratinized tissue an elimination of the chronic inflammation (arrow). Note that the new crown margin on the first premolar is now supragingival to the previous crown margin. The case is now in function for 11 years. Restorations by Dr. William Strupp Jr

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