Lengthening UCLA （ PowerPoint presentation）牙冠延长术加州大学洛杉矶分校（简报）课件.ppt

Inadequate clinical crowns for retention of new restorations. Flap design on buccal. Intrasulcular incisions, mesial vertical incision, distal wedge. Flap design on palatal. Reverse bevel incision removing gingival margin ,mesial vertical incision, distal wedge. Buccal full thickness flap elevation to expose at least 3 mm of crestal bone. Palatal flap elevation to expose at least 3 mm of crestal bone. The gingival level of new crown margin is estimated and bone removed so crestal level is 2 mm apical to this. 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. 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. Buccal flap sutured apically with increased tooth structure for crown preparation. Palatal flap repositioned with continuous sling mattress sutures and simple U shaped sutures of distal wedge and vertical incisions. Buccal Healing at 3 weeks. Palatal Healing at 3 weeks. Crowns placed at 6 weeks. After Before After Before 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 Poor crowns with recurrent caries. Soft tissue removal will be adequate for exposure of sound tooth for margins with a 1 mm Ferrule Extension. Electrosurgery used for gingivectomy. This can also be done with scalpels or laser. Tissue recontoured to expose root surfaces for adequate preparation of margins. Provisional restorations at 12 weeks. Marginal gingiva is now stable so final subgingival crowns can be completed. In esthetic areas a minimum of 12 weeks after-surgery is required to be sure no further gingival recession will occur. Final cro