3PresentsPresentsDr. E. Barrie Kenney Professor & Chairman Section of Periodontics
4Surgical Techniques for Crown Lengthening E. Barrie Kenney B.D.Sc., D.D.S., M.S., F.R.A.C.D.S.Surgical Techniques for Crown LengtheningTarrson Family Endowed Chair in Periodontics.Professor and Chairman Division of Associated Clinical Specialties UCLA School of Dentistry
5Indications for Crown Lengthening Development of Adequate Crown PreparationEstheticsIndications for Crown Lengthening
6Development of Adequate Crown Preparation Gingival Margins must not invade Biological Width Requirements for Periodontal Health.Development of Adequate Crown Preparation
7Biological Width Requirements There must be a minimum of 1mm between the apical level of the Junctional Epithelium and the bone crest.Biological Width Requirements
8Crown Margins which extend apically beyond the Junctional Epithelium can violate the requirements for periodontal health.An inappropriate crown margin increases plaque accumulation in close proximity to bone crest.
9Deeply placed crown margins causing gingival inflammation and pockets.
10Both Central Incisors and right lateral incisor have crowns violating Biologic Width concepts.
11Gargiulo A., Wentz F., Orban F. Dimensions and Relations of the Dentogingival Junction in Humans.J. Periodontol :261This study measured dimensions of tissues involved in Biological Width considerations.
12Used histologic sections to measure average dimensions of biologic width. These are not clinically accurate due to distortion with histologic processing.
13Gingival sulcusJunctional epitheliumConnection tissue attachment coronal to boneSulcus depth0.69 mm0.97 mm1.07 mmThis study said width of junctional epithelium plus connective tissue width was Biologic width; i.e. approximately 2 mm.Biologic Width
14However since then it has been shown that in probing the sulcus, the probe is generally at the deepest position of junctional epithelium.
15If a subgingival crown margin is placed in the middle of the gingival sulcus, the crest of bone should be a minimum of 2 mm apically positioned.
16When a subgingival crown margin is to be placed it may be necessary to surgically move the crestal bone margin apically so that there is at least 2 mm space between the margin and the bone.The necessary for 1 mm of connective tissue between the epithelium and bone is a minimal requirement. Larger dimensions can be compatible with healthy tissues.
17Use of Flap Surgery with Osseous Resection This is the method of choice when crown margins will impinge on the Biologic Width.Use of Flap Surgery with Osseous Resection
18Periapical Radiographs are needed to ensure sufficient root length is available. This case cannot have surgical crown lengthening and both premolars need to be extracted.
19This patient had extensive tooth wear and loss of Vertical Dimension
20There was insufficient clinical crown volume of the incisors for adequate retention so flap surgery was indicated.
36Buccal full thickness flap elevation to expose at least 3 mm of crestal bone.
37Palatal flap elevation to expose at least 3 mm of crestal bone.
38The gingival level of new crown margin is estimated and bone removed so crestal level is 2 mm apical to this.
39Buccal crown margins will be subgingival for esthetics Buccal crown margins will be subgingival for esthetics. So margins will be in middle of gingival sulcus i.e. 1 mm coronal to probing depth, add another 1 mm for connective tissue to determine bone level.
40Palatal crown margin will be supragingival Palatal crown margin will be supragingival. So allow 1mm for connective tissue plus 2 to 3 mm for sulcus with bone level 3 to 4 mm apical to level of crown margin.
41Buccal flap sutured apically with increased tooth structure for crown preparation.
42Palatal flap repositioned with continuous sling mattress sutures and simple U shaped sutures of distal wedge and vertical incisions.
48Gingivectomy for Crown Lengthening Most cases need flap and osseous surgery. Gingivectomy used when have adequate band of Keratinized tissue and bone crest is positioned apically with an initial wide Biological Width.Gingivectomy for Crown Lengthening
50Soft tissue removal will be adequate for exposure of sound tooth for margins with a 1 mm Ferrule Extension.
51Electrosurgery used for gingivectomy Electrosurgery used for gingivectomy. This can also be done with scalpels or laser.
52Tissue recontoured to expose root surfaces for adequate preparation of margins.
53Provisional restorations at 12 weeks Provisional restorations at 12 weeks. Marginal gingiva is now stable so final subgingival crowns can be completed.
54Final crown restorations should not be completed until a minimum of 6 weeks after surgery in order to minimized further tissue loss due to trauma of impressions.In esthetic areas a minimum of 12 weeks after-surgery is required to be sure no further gingival recession will occur.