Guidelines for Pin-Retained Amalgam Preparation and Restoration Accepted Accepted Accepted Unaccepted Guidelines 9 10 7.5 8.5 6.5 7 Below 6 – – – Follows central/ Significant Occlusal Slightly deviation Does not follow Bu/Li grooves deviation from Extensions from grooves grooves precisely grooves Outline Smooth curve Slightly sharp Markedly sharp Lack of a curve Slightly <; > ¼ Greater than 1/3 Width ¼ intercuspal 1/3 intercuspal intercuspal intercuspal Bu; gingival contact Contact broken broken by line of Tooth still in Bu; Li; gingival Proximal slightly more than explorer; Li contact contact with contact broken by Extensions line of explorer Bu; broken by no more adjacent tooth over 1mm gingival than 1mm Smooth, regular 90° Slight roughness; Significant Margins to unprepared tooth small areas where Beveled margins roughness structure margins not 90° Smooth, slight Rough; parallel Divegent Bu; Li Walls convergence Bu; Li Slight roughness walls walls walls Some sharp internal Rounded line line angles; Most internal line All internal line Line Angles angles; axio-pulpal line angle angles are sharp angles sharp line angle rounded still rounded Preparation 2.5mm from >2.5mm; <2.5mm >3.0mm; <2.0mm >3.5mm; <1.5mm Depth external walls Follows curvature Gingival floor Gingival floor Proximal of tooth; gingival Does not follow slightly greater/ less greater than 2mm Box Form floor 1mm wide; curvature of tooth than 1mm wide wide proper box form Pin placed too close Pin in pulp; Pin to external tooth fractured external Pin properly placed Pin too far pulpally Placement surface; incorrect tooth structure; pin angulation not present Adjacent Tooth No damage Slightly Significant Gross Damage
Guidelines for Pin-Retained Amalgam Preparation and Restoration Guidelines Accepted 9 – 10 Accepted 7.5 – 8.5 Accepted 6.5 – 7 Unaccepted Below 6 Occlusal Extensions Follows central/ Bu/Li grooves precisely Slightly deviation from grooves Significant deviation from grooves Does not follow grooves Outline Smooth curve Slightly sharp Markedly sharp Lack of a curve Width ¼ intercuspal Slightly <; > ¼ intercuspal 1/3 intercuspal Greater than 1/3 intercuspal Proximal Extensions Bu; gingival contact broken by line of explorer; Li contact broken by no more than 1mm Contact broken slightly more than line of explorer Bu; gingival Tooth still in contact with adjacent tooth Bu; Li; gingival contact broken by over 1mm Margins Smooth, regular 90° to unprepared tooth structure Slight roughness; small areas where margins not 90° Significant roughness Beveled margins Walls Smooth, slight convergence Bu; Li walls Slight roughness Rough; parallel walls Divegent Bu; Li walls Line Angles Rounded line angles; axio-pulpal line angle rounded Some sharp internal line angles; line angle still rounded Most internal line angles are sharp All internal line angles sharp Preparation Depth 2.5mm from external walls >2.5mm; <2.5mm >3.0mm; <2.0mm >3.5mm; <1.5mm Proximal Box Form Follows curvature of tooth; gingival floor 1mm wide; proper box form Gingival floor slightly greater/ less than 1mm wide Does not follow curvature of tooth Gingival floor greater than 2mm wide Pin Placement Pin properly placed Pin too far pulpally Pin placed too close to external tooth surface; incorrect angulation Pin in pulp; fractured external tooth structure; pin not present Adjacent Tooth Damage No damage Slightly Significant Gross