Marys Medicine

Jokstad.no



Applying color theory in clinical practice to Science Manager, FDI World Dental Federation Professor, University of Oslo, Norway Learning objectives Be familiar with the physical mechanisms of tooth coloring and its measurement Recognize possible etiology for discolorationRealize the potentials and limitations of esthetic restorative materials Be acquainted with different shade guides and their characteristics Know of commercially available digital systems for shade matching Know procedures for optimizing correct shade matching & communication


Light- tooth interaction




Colors for teeth and dental materials are reported in the literature as: • Munsell values (Hue, Chroma, Value)Tristimulus values X, Y, Z CIE chromaticity values Y(%), x, yCIE L*a*b



CIE L*a*b color system L=100, White
L=0, Black
E*= Change of L*a*b values Proportional contributors to tooth color • The proportional contribution of enamel, dentin, pulp, gingiva and mucosa to the spectral reflection from the tooth in isolation remain uncertain Proportional contributors to tooth color • The proportional contribution of enamel, dentin, pulp, gingiva and mucosa to the spectral reflection from the tooth in isolation remain uncertain • In general, dentin E*= 8(1 – 15) contributes the most as it is more chromatic than enamel Proportional contributors to tooth color • The proportional contribution of enamel, dentin, pulp, gingiva and mucosa to the spectral reflection from the tooth in isolation remain uncertain • In general, dentin contributes the most as it is more chromatic than enamel • Enamel is very translucent and more grey-blue than Learning objectives 1. Be familiar with the physical mechanisms of tooth coloring and its measurement 2. Recognize possible etiology for discoloration and best treatment • Extrinsic• Intrinsic Extrinsic discolored teeth – etiology N1-type colored material (chromogen) binds to the tooth surface. The color of the chromogen is similar to that of dental stains caused by tea, coffee, wine, chromogenic bacteria, and metals. Extrinsic discolored teeth – etiology N1-type colored material (chromogen) binds to the tooth surface. The color of the chromogen is similar to that of dental stains caused by tea,coffee, wine, chromogenic bacteria, and metals.
N2-type colored material changes color after binding to the tooth. The stains actually are N1-type food stains that darken with time. Extrinsic discolored teeth – etiology N1-type colored material (chromogen) binds to the tooth surface. The color of the chromogen is similar to that of dental stains caused by tea, coffee, wine, chromogenic bacteria, and metals. N2-type colored material changes color after binding to the tooth. The stains actually are N1-type food stains that darken with time.
N3-type colorless material or prechromogen binds to the tooth and undergoes a chemical reaction to cause a stain. N3-type stains are caused by carbohydrate-rich foods (eg, apples, potatoes), stannous fluoride, and chlorhexidine.
Discolored teeth – best treatments Active agent
AirScaling / Brushing with (whitening) toothpaste +Patient counseling Heriditary defects Restorative treatment Tetracycline staining Custom bleaching trays worn by 10 % carbamide peroxide patient daily for six to 12 weeks Single or multiple discolored External bleaching—in-office one 30 - 38 % H- peroxide, alone or with heat or light Multiple teeth and entire Custom bleaching trays worn by 10 % carbamide peroxide arches, most effective for patient daily for two to six weeks yellow or brown discoloration Isolated brown or white Microabrasion followed by neutral Abrasives + HCl up to 36 % discolorations of shallow White discoloration on Microabrasion followed by custom Abrasives and acid; 10 % carbamide peroxide Endodontically treated teeth Internal bleaching—in-office or Na perborate or 35 % H Intrinsic discolored teeth – etiology 1. Hereditary defects
Dentinogenesis imperfecta.

Teeth relatively normal at eruption Discolor increases with time More and more translucent, pink yellow, brownish or grey-brown Enamel may chip off with subsequent heavy dentin discoloration Intrinsic discolored teeth - etiology 1. Hereditary defects
Dentinogenesis imperfecta. Normal at eruption.
Translucent, yellow, pink, brownish or grey-brown. The enamel may chip off with subsequent heavy discoloration of dentin Amelogenesis imperfecta. 2 categories:1. Hypoplastic:Teeth smooth and glossyColor is orange, reddish or brown2. Hypomineralised:Color can vary between bone white, yellow, red and black The enamel may chip off later Intrinsic discolored teeth - etiology 2. Toxic effects during tooth development
Fluorosis: Surface may range between small opaque white spots to extensive yellow-brown bands and/or areas Intrinsic discolored teeth - etiology 2. Toxic effects during tooth development
Fluorosis: The surface may range between small opaque white spots to
extensive yellow-brown areas Tetracycline:Chemical complex to ameloenamel proteinsColor can vary between light to dark yellowCharacteristic fluorescence in UV lightCervically usually darker due to thin enamel Intrinsic discolored teeth - etiology Amelogenesis imperfecta 2.Toxic effects during tooth development: Fluorosis -
following a trauma, due to internal bleedingin the pulp, with retention of porphyrines andiron in the dentin.The discoloration may bereversible or remain, even if the pulparemains vital 4.Pulp necrosis: Results usually in a tooth discoloration, but not always Intrinsic discolored teeth - etiology 1. Hereditary: Dentinogenesis & Amelogenesis imperfecta
2. During tooth development: Fluorosis - Tetracycline
3. Trauma: Internal bleeding in the pulp, with retention of
porphyrines and iron in the dentine 4. Pulp necrosis: Usually tooth discoloration, but not always 5. Other reasons:Degradation products from metallic restorativesSeldom bleeders' diseasesSurface erosions Unknown reasons, possibly related to some childhood illness. E.g. hepatitis over a p Discolored teeth – best treatments Active agent
AirScaling / Brushing with (whitening) toothpaste +Patient counseling Heriditary defects Restorative treatment Tetracycline staining Custom bleaching trays worn by 10 % carbamide peroxide patient daily for six to 12 weeks Single or multiple discolored External bleaching—in-office one 30 - 38 % H- peroxide, alone or with heat or light Multiple teeth and entire Custom bleaching trays worn by 10 % carbamide peroxide arches, most effective for patient daily for two to six weeks yellow or brown discoloration Isolated brown or white Microabrasion followed by neutral Abrasives + HCl up to 36 % discolorations of shallow White discoloration on Microabrasion followed by custom Abrasives and acid; 10 % carbamide peroxide Endodontically treated teeth Internal bleaching—in-office or Na perborate or 35 % H Learning objectives 1. Be familiar with the physical mechanisms of tooth coloring and its measurement 2. Recognize possible etiology for discoloration and best treatment 3. Realize the potentials and limitations of esthetic restorative Presently, there are no spectrophotometric quality control of materials with minimum criteria of performance Among the direct materials, composite resins possess the best optical-physical properties regarding Technique in 1980 New products in 2004 Dental Materials- composites, clinical observations • Most materials become more opaque and lighter after a while intraorally, due to water uptake – This varies markedly among different materials Dental Materials- composites, clinical observations Most materials become more opaque and lighter after a while intraorally, due to water uptake • Chemically polymerised composites discolor more into yellow than thelight polymerisation chemicals in the resin Dental Materials- composites, clinical observations Most materials become more opaque and lighter after a while intraorally, due to water uptake more into yellow than the light polymerised dueto the polymerisation chemicals in the resin • Chemically polymerised composites with microfillers discolor more compared to those with macrofillers.
Composites are tested in laboratory for discoloration potential. E.g.
1. Color Stability, in 2. Color Stability, 3. Stain Resistance, in 37/80°C Coffee 4. Stain Resistance, An absolute requirement is adequate preparation depth! The thickness of a restoration / veneer is critical to obtain a correct reflection spectrum and thus acceptable shade Not removing enough tooth substance will either result in poor esthetics or to overcontouring with risk for subsequent gingival recession. This is especially critical cervically. Learning objectives 1. Be familiar with the physical mechanisms of tooth coloring and its measurement 2. Recognize possible etiology for discoloration and best treatment 3. Realize the potentials and limitations of esthetic restorative materials 4. Be acquainted with different shade guides and their characteristics Composite / Hybrid
VITA/ Biodent / Own
Composite / Hybrid
Composite / GIC / Hybrid / Ceram /
Biodent/ VITA/ Own
Composite / Hybrid / GIC
Biodent / VITA
Hybrid / GIC / Ceram
Composite / Hybrid / Prefab teeth
Composite / Ceram
VITA / Vintage Halo
Ceram / Prefabricated teeth
VITA VITA3D
Composite / Ceram
• Large deviations between supposedly similar tooth shades from the same producer is not uncommon Large deviations between supposedly similar tooth shades from the same producer is not uncommon • Custom-made color shades using the actual restorative material is claimed to be better than using a standard color shade Large deviations between supposedly similar tooth shades from the same producer is not uncommon Custom-made color shades using the actual restorative material is claimed to be better than using a standard color shade • Some tooth shades changes following immersion in disinfectants. Keep away from chlorine-containing solutions! The 5 most common shade guides in use internationally Bioform -> Biotone ->Trubyte Bioblend -> Portrait IPN Brown- Brown
1990; Vivadent -> Kerascop Changed in the mid-seventies A3.5 & D4 added in 1980 B1 & D1 sometimes excluded ―VITA-Shade‖ guides from different producers may often differ markedly from the original Reddish- 43
‖old‖ VITA shades Learning objectives Be familiar with the physical mechanisms of tooth coloring and its measurement Recognize possible etiology for discoloration and best treatment Realize the potentials and limitations of esthetic restorative materials Be acquainted with different shade guides and their characteristics 5. Know of commercially available digital systems for shade matching Digital Shade Matching Systems A hand held optic device with dual light source connected through fiber optics to a spectrophotometer Digital Shade Systems • Dental Color Analyser (clearlight.com/ aei) • Metalor-ikam system • ShadeVision /ShadeRite • Spectroshade • ShadeEye NCC Digital Shade Systems -Benefits • Improved communication between • Can integrate with – Intra-oral camera– Digital Camera– Image enhancing software– Mouth Simulator– Printer Learning objectives Be familiar with the physical mechanisms of tooth coloring and its measurement Recognize possible etiology for discoloration and best treatment Realize the potentials and limitations of esthetic restorative materials Be acquainted with different shade guides and their characteristics Know of commercially available digital systems for shade matching 6. Know procedures for optimizing correct shade matching & communication Fixed Prosthetic Dentistry- shade selection Before you start…1. Have the patient remove lipstick or bright makeup 2. If patient is wearing bright clothing, drape him or her with a neutral colored cover, i.e. light blue or light gray 3. Keep a surface with a neutral color nearby 4. Clean the teeth if doubt of extrinsic discoloration 5. Don't recline your patient – keep at eye level 6. Do not wear glasses that changes with light Fixed Prosthetic Dentistry- shade selection … right environment1. Do not use direct lights. Lighting should be in the most natural light possible. Incoming light may be altered if the window in your operatory has a lot of greenery around it Fixed Prosthetic Dentistry- shade selection … right environment1.
Do not use direct lights. Lighting should be in the most natural light possible. Incoming light may be altered if the window in your operatory has a lot of greenery around it 2. Compare your shade selection under varying conditions such as with lip retraction versus lip down and when the patient moves their head in different directions or lighting angles Fixed Prosthetic Dentistry- shade selection … right environment1.
Do not use direct lights. Lighting should be in the most natural light possible. Incoming light may be altered by greenery around the window Compare your shade selection under varying conditions such as with lip retraction versus lip down and when the patient moves their head in different directions or lighting angles 3. Have also your patient press their tongue against the lingual surface, when doing an anterior tooth restoration Fluorescent Natural daylight Incandescent The same teeth look different under different light Fixed Prosthetic Dentistry -shade selection . right time1. Select the shade at the beginning of the session before the tooth becomes dehydrated and your eyes fatigued 2. An impression and the use of rubber dam will cause lighter teeth. Retraction cord may influence the tooth color both ways. Anaesthetics too? 3. The canines are good for selecting shade as they have the highest chroma of the dominant color of the teeth 4. Once the tooth is fully prepared, use your guide to select the shade of the dentin in the tooth's body 1. The first impression is usually the most accurate in shade selection 2. It is important avoid fatiguing the eyes. Do not stare for >3-10 secs. Gazing at a neutral color, e.g. blue or grey for approx. 30 seconds will help to cleanse and refocus the eyes Fixed Prosthetic Dentistry - shade selection . the process …1.
Place the shade tab parallel to the facial surface of the teeth, not in front or behind Arrange each tab on the guide so that the incisal edge is facing out or away from the tab holder. Since incisal shading has the greatest influence on value, it is helpful to position the incisal area of the tabs closest to the teeth you are shading. This will also help avoiding color choice being influenced by the hue area of the tab Always select the value reading first. It may help to squint Now that the value reading has been taken, use your hue guide to select the color reading Fixed Prosthetic Dentistry -shade selection … finalising 1. Make your final shade selection after comparing your selections with those of a staff member and/or ask the patient's opinion on your choice 2. Make a mental note of morphological details 3. If unable to match, choose a lower chroma 4. Take photo with shade tab if possible Communicate this to laboratory Get as detailed as possible with characterization Every piece of information helps: – Surface texture– Glaze– Translucency– Wear– Proximal view with incisal/thickness of enamel – Any unique color characterizations of the dentine

Source: http://www.jokstad.no/chinacol.pdf

math.helsinki.fi

Second order logic and set theory Both second order logic and set theory can be used as a foundation for mathematics, that is, as a formal language in which propositions ofmathematics can be expressed and proved. We take it upon ourselvesin this paper to compare the two approaches, second order logic on onehand and set theory on the other hand, evaluating their merits andweaknesses. We argue that we should think of first order set theoryas a very high order logic.

gablofen.com

TRATAMIENTO DE LA ESPASTICIDAD GRAVEGablofen® para ITB TherapySM (Intrathecal Baclofen Therapy—Terapia Intratecal con Baclofen) aprobada por la FDA INFORMACIÓN IMPORTANTE SOBRE RIESGOS ADVERTENCIA: NO DEJE DE TOMAR GABLOFEN DE REPENTE Si deja de administrarse baclofen repentinamente