Crown Lengthening and Prosthodontic Considerations
When practicing dentistry to an optimal level, the clinician is often faced with a dilemma of insufficient clinical crown or dimension to the periodontal attachment apparatus. The surgical intervention of “crown lengthening” positions the new dentogingiva
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E. Dwayne Karateew, Taylor Newman, and Farah Shakir
12.1 Introduction Crown lengthening surgically increases the clinical crown in an incisal-apical dimension for either restorative or esthetic needs or a combination of both. The procedure may include apical repositioning of the gingival margin and osseous contouring. From a restorative standpoint, indications include insufficient clinical crowns for retention, subgingival caries, and subgingival fractures. Esthetically, short clinical crowns and cases of excess gingival display can also benefit from surgical crown lengthening [1, 2]. Case assessment prior to restorative treatment must take into consideration the biologic width and the mucogingival status (Fig. 12.1). Failure to do so can be detrimental to long-term periodontal health, resulting in subsequent inflammation, bone loss, and gingival recession [2, 3].
12.1.1 Biologic Width Decay or placement of a restorative margin apical to the gingival sulcus risks impingement on the supracrestal fiber attachment and violation of the biologic width. The biologic width refers to the aspect of soft tissue, the dentogingival complex, that is attached to the tooth coronal to the alveolar bone. It is comprised of the connective tissue attachment, the epithelial attachment, and the gingival sulcus (Fig. 12.2) [3, 4]. Early work by Gargiulo et al. [5] on cadaver skulls found average measurements of 0.69 for the sulcus depth, 0.97 mm for the epithelial attachment, and 1.07 mm for the connective tissue attachment. A minimum of 3 mm from the alveolar bone to the restorative margin has been indicated to avoid infringement on E. D. Karateew (*) · T. Newman · F. Shakir Department of Periodontology, College of Dentistry, University of Illinois at Chicago, Chicago, IL, USA e-mail: [email protected] © Springer Nature Switzerland AG 2020 S. Nares (ed.), Advances in Periodontal Surgery, https://doi.org/10.1007/978-3-030-12310-9_12
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Fig. 12.1 Relationship of the sulcular and junctional epithelium, the connective tissue attachment, and the underlying alveolar crest. Biologic insult (golden- yellow) could include decay, external resorption, and restorative margin. This extends apically into Zone A and B causing an inflammatory response to the physical insult. Osseous resection, Zone C, must be conducted to surgically re-create the biologic width at a more apical position. Health can then be restored
A | Sulcular and junctional Epithelium
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B | Connective Tissue
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C | Osseous Resection
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2 Zone of Biologic Width 3
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Fig. 12.2 Detail schematic of the periodontal structures. (1) Enamel of the clinical crown, (2) Cementum, (3) Gingival fibers, (4) Gingival connective tissue, (5) Periodontal ligament, (6) Alveolar bone, and (7) Dentin
12 Crown Lengthening and Prosthodontic Considerations
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the dentogingival complex and maintenance of the biologic width [6]. Kois [3] has expressed that the biologic width “averages” previously noted are quite variable between individuals and
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