[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-402619-105":59,"doc-detail-402619-en":130},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":123,"head_meta":125,"extra_data":127,"updated_unix":129},105,"en","improving-your-margins-clinical","Improving your margins - Clinical","","Improving your margins focuses on the dental-restoration margin as a critical transition zone where clinical technique and material selection directly determine fit, seal, strength, and long-term durability. It explains how marginal discrepancies cause plaque retention and microleakage, compromising tooth/restoration integrity and aesthetics through staining and visible differences. The document then reviews finishing-line and margin design principles across all-ceramic, all-metal, and porcelain-fused-to-metal (PFM) restorations, including common finishing-line concepts and reduction guidance to achieve lifelike outcomes.",{"@graph":69,"@context":122},[70,84,105],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/improving-your-margins-clinical/402619/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/improving-your-margins-clinical/402619.png","ImageObject",300,407,{"name":92,"@type":93},"Ivy","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-11-04","2026-09-27",true,{"@type":102,"interactionType":103,"userInteractionCount":44},"InteractionCounter",{"@type":104},"ViewAction",{"@type":106,"mainEntity":107},"FAQPage",[108,114,118],{"name":109,"@type":110,"acceptedAnswer":111},"Why are crown margins often considered a clinically weak point?","Question",{"text":112,"@type":113},"Marginal discrepancies disturb smooth tooth surfaces and increase vulnerability to plaque accumulation. Microleakage at the margin allows passage of ions, molecules, fluids, or bacteria between the tooth and restoration.","Answer",{"name":115,"@type":110,"acceptedAnswer":116},"How do marginal aesthetics and staining become problematic for tooth-coloured restorations?",{"text":117,"@type":113},"Visible margins can detract from aesthetics by highlighting differences in shade, translucency, and surface finish between the restoration and adjacent tooth structure. Over time, the junction is often further exacerbated by staining.",{"name":119,"@type":110,"acceptedAnswer":120},"What is the main reason PFM restorations can look lifeless or unnatural?",{"text":121,"@type":113},"Inadequate tooth reduction can leave insufficient space for the needed thickness of veneering porcelain to block out the metal substructure, resulting in an overbuilt, dull, opaque-looking crown.","https://schema.org",{"og:url":83,"og:type":124,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":126,"canonical":83},"index,follow",{"doc_id":128,"site_id":62},402619,1790740876,{"code":4,"msg":5,"data":131},{"doc_id":128,"user_id":132,"nickname":92,"user_avatar":133,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":134,"file_id":135,"file_url":136,"file_type":137,"file_size":138,"view_count":44,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":29,"language":139,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":140,"faqs":141,"seo_title":142,"seo_description":67,"update_tm":143,"read_time":144,"preview_page_count":4},549758252649,"https://ap-avatar.wpscdn.com/avatar/8000253669c5317157?_k=1778319167496531819","Clinical  \nImproving your margins  \nPhilip Newsome and Siobhan Owen  \nA restoration’s margin marks the transition between the restoration itself and the finishing line of the adjacent tooth tissue . This is a critical area and when careful tooth preparation is combined with an appreciation of the needs of the technician, in terms of the physical requirements and limits of the chosen restorative material, the resulting restoration can be both like-like and durable ( Figure 1) . Unfortunately, crown margins are all too often considerably less than satisfactory ( Figure 2) with tooth/restoration interface representing a significant clinical weak point for the following reasons:  \n• Any marginal discrepancies disrupt smooth tooth surfacesand hence render the site vulnerable to plaque accumulation while microleakage at the margin allows the passage of ions, molecules, fluids or bacteria between the prepared tooth and the restorative material (Taylor 1992) .  \n• In the case of tooth-coloured restorations, visible margins often detract from the overall aesthetic result by highlighting relative differences in shade, translucency and surface finish of the restorative material and the adjacent tooth structure . After a period of time this is often exacerbated by staining of the junction.  \n• The restoration is often at its thinnest in the marginal region and hence at it ’s most vulnerable to failure, depending on the material used, and the forces being exerted on the margin.  \nFinishing line/restoration margin design  \nThis is largely dictated by the choice of restorative material (Figure 3) . For example, margins for all-ceramic restorations differ from those recommended for all-metal restorations  \nPhilip Newsome BChD PhD MBA FDS RCS (Ed) MRD RCS (Ed). Associate Professor at the Faculty of Dentistry of Hong Kong University.  \nDr Siobhan Owen, BDS. Private Practice, SW England.  \nFigure 1: Excellent clinical technique allows the technician to produce beautiful restorations with excellent marginal fit and correct emergence profile.  \nand finally for porcelain-fused-to-metal ( PFM) restorations which in turn may require different margins within the one preparation depending on whether metal or porcelain is required at the restoration/tooth interface.  \nFull veneer metal crowns  \nThe knife-edge finishing line is commonly used in these situations because of its simplicity and conservative nature. The resulting feather edge on the crown is possible because of the metal ’s strength and ductility. Chamfers and shoulders (see below) are also possible although problems may arise should shrinkage of the metal during casting lead to a gap between tooth and preparation.  \nPorcelain-fused-to-metal (PFM) restorations  \nPFM restorations are far and away the most commonlyprescribed of all indirect restorations worldwide owing their popularity to their acceptable aesthetics, strength, durability, simplicity and versatility. When planned and executed properly, the PFM restoration is capable of providing a reasonable aesthetic outcome although  \n36 INTERNATIONAL DENTISTRY SA VOL. 11, NO. 6  \nClinical  \nFigure 2: Microleakage is clearly visible within the chamfer margin of this ceramic veneer (Figure 2a) while gross deficiencies result in extremely unaesthetic restorations (Figures 2b and c).  \nwithout due care and attention all too many appear lifeless and unnatural. The most common cause of this is inadequate tooth reduction leaving the technician withinsufficient space for sufficient thickness of veneering porcelain to block out the metal substructure. The result is usually an overbuilt dull, opaque-looking crown (Figure 4) . For PFM restorations to have any chance of appearing lifelike, sufficient tooth structure must be removed to accommodate both metal and ceramic ( Barghi 1982) . Chiche (1995) recommends a facial reduction of between 1.4 mm and 1.7 mm (as recorded at the junction of the incisal and middle thirds of the crown where the opaque layer ","cbCaikX41Y7faP09","https://ap.wps.com/l/cbCaikX41Y7faP09","pdf",301338,"English","# Clinical\n## Improving your margins\n## Finishing line/restoration margin design\n## Full veneer metal crowns\n## Porcelain-fused-to-metal (PFM) restorations\n## The beveled shoulder\n## Knife edge","[{\"question\":\"Why are crown margins often considered a clinically weak point?\",\"answer\":\"Marginal discrepancies disturb smooth tooth surfaces and increase vulnerability to plaque accumulation. Microleakage at the margin allows passage of ions, molecules, fluids, or bacteria between the tooth and restoration.\"},{\"question\":\"How do marginal aesthetics and staining become problematic for tooth-coloured restorations?\",\"answer\":\"Visible margins can detract from aesthetics by highlighting differences in shade, translucency, and surface finish between the restoration and adjacent tooth structure. Over time, the junction is often further exacerbated by staining.\"},{\"question\":\"What is the main reason PFM restorations can look lifeless or unnatural?\",\"answer\":\"Inadequate tooth reduction can leave insufficient space for the needed thickness of veneering porcelain to block out the metal substructure, resulting in an overbuilt, dull, opaque-looking crown.\"}]","Improving your margins - Clinical | PDF",1790532175,15]