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Smile design /certified fixed orthodontic courses by Indian dental academy


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The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.

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Smile design /certified fixed orthodontic courses by Indian dental academy

  1. 1. INDIAN DENTAL ACADEMY Leader in continuing dental education
  2. 2. INTRODUCTION In our modern competitive society, a pleasing appearance often means the difference between success and failure in both our personal and professional lives. Scottish physiologist Charles bell (1774-1842)was quoted as remarking that the thought is to the word that the feeling is to the facial expression. He pointed out in 1806 that a smile could convey a thousand different meanings , yet it is the most easily recognized expression. And because the mouth is one of the focal points of the face , it should come as no surprise that the smile plays a major role in how we perceive ourselves, as well as in the impressions we make on the people around us.
  3. 3. A charming smile can open doors and knock down barriers that stand between you and a fuller , richer life . An attractive or pleasing smile clearly enhances the acceptance of the individual in the society where he belongs and the character of the smile influences to the great extent the attractiveness and the personality of the individual.
  4. 4. Basically the smile is dependant on the musculature and the presence of the teeth. But every person is not fortunate enough to have a beautiful smile . The answer to the above problem is the esthetic dentistry which has developed leaps and bounds with the latest technologies and materials. Prosthodontist is probably the best person to identify the quality of smile. Further he is also able to change the quality of smile with the recently available innovative techniques and the state of art restorative materials and to plan restorations, to harmonize with the smile.
  5. 5. CLASSIFICATION OF SMILE (Solomon E.G.R.) 1) Depending on the nature of labial mucous membrane a) papilla smile b) Gingival smile c) Mucosa smile 2) Dependant on the lip component a) Straight smile b) Convex smile c) Concave smile
  6. 6. Definitions: Glossary of Prosthodontic terms. January 1999. Esthetics 1. Pertaining to the study of beauty and the sense of beautiful. Descriptive of a specific creation that results from such study; objectifies beauty and attractiveness and elicit pleasure. 2. Pertaining to sensation.
  7. 7. Esthetic reshaping Modification of the surfaces of teeth to improve appearance Esthetics (adj. 1798) 1. The branch of philosophy dealing with beauty. In dentistry, the theory and philosophy that deal with beauty and beautiful, esp. with respect to the appearance of a dental restorations, as achieved through its from and or color. Those subjective and objective elements and principles underlying the beauty and attractiveness of an object, design or principle.
  8. 8. Dental Esthetics The application of the principles of esthetics to the natural or artificial teeth and restorations. (GPT 1999) Esthetic Dentistry can be defined as the art and science of dentistry applied to create or enhance beauty of an individual within functional and physiological limits.(Ratnadeep Patil)
  9. 9. Cosmetic dentistry is application of the principles of esthetics and certain illusionary principles, performed to signify or enhance beauty of an individual to suit the role he has to play in his day-to-day life or otherwise. (Ratnadeep Patil) Smile designing is a process whereby the complete oral hard and soft tissues are studied and evaluated and certain changes are brought about which will have a positive influence on the overall esthetics of the face. These changes are governed by the principles of esthetic dentistry. Hence, a good smile design would naturally and effortlessly blend with the rest of the face to provide an esthetic and functional complex
  10. 10. “ A well designed smile is a product of consolidated efforts accomplished by accurate diagnosis, methodical treatment planning, use of advanced materials and contemporary techniques rendered by the skilled dentist”.
  11. 11. Physical attributes of the elements of the dento-facial composition The artistic parameters to be considered for essential beauty and those which are subtly present in natural beauty form the fundamental principles of esthetics. Understanding these artistic parameters of beauty and co-relaing them to the dentofacial complex will enable the dentist to appropriately scale esthetics in any dento-facial composition. Composition means the act of combining elements or parts to form a whole. There are various physical attributes of the elements of a composition that impart the esthetic value. The various physical attributes of the elements of a composition are:
  12. 12. Contrast: It is that factor which makes the various elements of a composition visible. The eye can differentiate the parts of an object due contrast of colors,lines, patterns, textures, etc. The relationship between the different parts of the face (facial), the teeth and the gums (dental) made visible by contrast constitutes the dento-facial composition.
  13. 13. Unity or oneness: “It gives different parts of the composition the effect of a whole”. Unity can either be static, when repeated shapes or designs are seen as in inanimate things, like the composition of crystals; or dynamic and changing as in living beings. Unity between different parts of the face, and teeth is essential to give the effect of oneness or wholeness to the dento-facial composition (Fig.2-1b)
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  15. 15. Cohesive and segregate forces: Any element which tends to unify a composition is a cohesive force. Segregative forces are those elements which break the monotony of the composition. Naturalness has combination of cohesive and segregative forces. A proper mix of segregative and cohesive forces adds variety to the composition making it more dynamic and interesting
  16. 16. Symmetry: It is the regularity of arrangement of forms either from either from left to right as in horizontal symmetry, or from a central point to either side like a mirror image as in radiating symmetry. The horizontal symmetry looks repetitive and uninteresting while the radiating symmetry looks dynamic and interesting. In a dento-facial composition radiating symmetry of the teeth is more esthetically appealing and is associated with youthfulness while horizontal symmetry is less appealing and is associated with aging.
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  18. 18. Proportion: To be able to give a certain mathematical representation of beauty for numerically expressing the relationship of the various units that combine to make a composition, the term proportion is used. The relationship of the various units which are different from each other in a composition but are associated with each other through a certain repetitive mathematical factor is the repeated ratio. The proportion between the various elements of a harmonious composition, in which the cohesive and segregative forces are equally balanced,and whichhas its various units in an esthetically appealing respective proportion to each other is the golden proportion
  19. 19. Dominance: It exists when a strong centralized structure is surrounded by well-demarcated, characterized structures. In a dento-facial composition it creates immaculate unity leading to a harmonious composition. The absence of dominance makes the composition weak. Color, shape and size are the factors which can control dominance).
  20. 20. Balance: It is achieved when there is an exact equilibrium between the forces present on either side of the fulcrum in a composition. In dentistry this implies the balance of the elements in relation to the midline. If any elements are imbalance on one side then, to create a visual balance either these elements are moved towards the midline or are counter-balanced with opposite elements to regain the balance. In balance the weight of the elements far away from the fulcrum grows in importance
  21. 21. Visual tension is the tension brought about by the presence of certain elements that cause an imbalance in the given composition. If the presence of these factors is closer to the fulcrum, the effect of the tension into the fulcrum,the effective the tension induced is more magnified as against their presence further from the fulcrum. A distally inclined lateral incisor on one side is compensated by a more mesial inclination of the first premolar on the opposite side to reduce the effective visual tension. These variations are naturally found in dentitions explaining the reason why sometimes irregularities in inclinations still produce pleasant smiles.
  22. 22. The esthetic orientation of the dental composition with the entire facial composition can be achieved by taking into consideration the references, smile elements, proportions and symmetry. These are the factors of esthetic compositions and they help the dentist in determining tooth display, size, arrangement and alignment during the diagnosis and treatment phase.
  23. 23. The dento-facial frame constitutes the teeth and gingiva related to the lips and then to the entire face. The oral frame is determined by the anatomy and mobility of the tissues when in function surrounding the teeth and gingiva .The exposed portion of the oral elements i.e. teeth and gums within the oral frame during a smile is called the smile window. .
  24. 24. The anatomical elements of the face and the biological elements that include the functional and phonetic elements, provide the reference frames, guidelines and points. These elements help the dentist to achieve a general sense of orientation and diagnosis. References can be classified as horizontal references, vertical references, sagital references and phonetic references.
  25. 25. Horizontal references: The horizontal perspective of the face is provided by the interpupillary line the commissural line. The inter-pupillary line helps to evaluate the orientation of the incisal plane, the gingival margins and the maxilla. An imaginary horizontal line through the incisal plane and the gingival margins should be visibly parallel to the inter-pupillary line. This helps to diagnose any asymmetry in the tooth position or gingival location. When an imaginary line is drawn across the gingival margins, it may not be parallel to the inter-pupillary line indicating a certain degree of canting of the maxilla. Certain amount of canting of maxilla is considered normal and in such cases mild correction of the gingival margins can achieve a pleasing symmetry Severe canting may require an interdisciplinary approach involving surgical repositioning of the maxilla.
  26. 26. Vertical references: The facial midline serves to evaluate the location and axis of the dental midline and the medio-lateral discrepancies in tooth position.The inter-pupillary line and the facial midline emphasize the ‘T’ effect in a pleasing face. The dental midline, if perpendicular to the inter-pupillary line and coinciding with the bridge of the nose and the philtrum, produces an attractive orientation of the smile.
  27. 27. Axial inclination is the direction of the anterior teeth in relation to the central midline and becomes progressively more pronounced from the central incisor to the canine. There is a definite mesial inclination to all the anterior teeth related to the midline. The axes of the premolars and the first molar on either side also show mesial inclination in relation to the midline. The perception of tooth inclination can be viewed from the frontal aspect around the central vertical midline, which acts like a fulcrum around which axial inclination of teeth on either side exhibit a phenomenon of balance of lines Natural smiles show a deviation from these standard axial inclination. Deviations in axial inclination cause a visual tension when beyond the point of equilibrium
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  29. 29. Sagittal references: Soft tissue analysis at a standardized position helps in studying the profile of an individual. The contours of the upper and lower lip support is determined by the position of the anterior teeth and can be used as a guide for the placement of teeth when planning restorations. The lip protrusion, the amount of prominence of chin, recession or prominence of the nose and its degree, all help in profile analysis for diagnosis and treatment planing.
  30. 30. The E-line or esthetic line is an imaginary line connecting the tip of the nose to the most prominent portion of the chin on the profile, ideally the upper lip is 1-2 mm behind and the lower lip 2-3mm behind the E-line. Any change in the position of the E-line indicates the abnormality in the upper or lower lip position. The main support of the upper lip is contributed by the gingival two thirds of the maxillary central incisors rather than the incisal one third According to studies by Maritato and Douglas the lip support is a better guide of tooth position than of incisal edge position.
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  32. 32. The relationship of the maxillary incisl edges to the lower lip is a guide for the placement of the incisal edge position and length. The pronunciation of the ‘F’ and ‘V’consonants helps determine the position of the incisal edges. On pronouncing ‘F’ and ‘V’ the incisal edges should make a definite contact at the inner vermilion border of the lower lip Thus the position of the incisal third of the maxillary central incisor can be determind.
  33. 33. Phonetic references: Phonetics play a part in determining maxillary central incisor design and position. ‘F’ and ‘V’ sounds are used to determine the tilt of the incisal third of the maxillary central incisors and their length. The ‘M’ sound is used to achieve relaxed rest position and repeated at slow intervals can help evaluate the incisal display at rest position ‘S’ or ‘Z’ sounds determine the vertical dimension of speech.. Its pronunciation makes the maxillary and the mandibular anterior teeth come in near contact and determine the anterior speaking space The amount of posterior speaking space varies with the amount of mandibular protrusion necessary to bring the anterior teeth in near contact for the ‘S’ sound.
  34. 34. Smile elements: The extent of the smile is outlined by the curvature of the upper and lower lip and the position of the angle of the mouth, and it determines the degree of exposure, both in the anterior and posterior teeth, gingiva as well as the width of the buccal corridor Smiles can be classified as passive, active (moderate) and laugh. In a passive smile the lips are parted slightly away from the rest position expressing content, passion, desire, surprise, etc. In an active smile the lips move to a significant extent away from the rest position displaying more teeth and even gums, expressing joy, welcome, happiness, etc. Laugh is an instant fluctuation from an active smile position where the facial muscles instantly act leading to maximum exposure of the teeth and gums. Humorous and funny situations usually lead to such an expression.
  35. 35. Lip and lip lines: The length, the curvature and the shape of the lips significantly influence the amount of tooth exposure during rest and in function. A prominent tooth display is associated with a youthful smile and most patients would like to seek the benefit of the same. Some researchers demonstrated that the average maxillary incisor display with the lips at rest is 1.91mm in men and 3.40 mm in Women Patient’s with short upper lips and younger patients generally display more maxillary tooth structure which may be up to 3.65mm.
  36. 36. Upper lip line helps to evaluate the length of the maxillary incisor exposed at rest and during smile and the vertical position of the gingival margins during smile. The upper lip line can be classified as low, medium or high depending upon the amount of tooth or gingival display that is available at rest of during a moderate smile. The gingival margins may be displayed in high lip line cases. The most apical position of the gingiva over the facial aspect of the maxillary central incisor and canine is slightly distal to the long axis of the tooth while in the maxillary lateral incisor it is at the long axis of the tooth. This is called the gingival zenith
  37. 37. Whenever a patient displays the gingival margins easily on smiling or speaking, a definite pattern of the gingival display can be recorded. This pattern can be either esthetic or unesthetic A smile can be termed “toothy” if more than 6mm of incisal display is seen at rest position or “gummy” if more than 3mm of gingival tissues are displayed in moderate smile)
  38. 38. Lower lip line helps to evaluate the buccolingual position of the incisal edge of the maxillary incisors and the curvature of the incisal plane
  39. 39. Smile line: It is an imaginary line passing through the incisal edges of the upper anterior teeth. The smile line usually coincides or runs parallel to the inner vermilion border of the lower lip. In a youthful smile the incisal edges of the central incisors and canines are aligned on a convexity and are linger than the lateral incisors, incisal embrasures gradually deepen from central incisor to the canine, giving the appearance of the wings of a gull. Thus the incisal plane is said to have a gull-wing apperance When the incisal edges of the central incisors and canines are aligned on a convexity the incisal plane is convex. Reduced incisal embrsures and leveling of the gull-wing effect as in a straight smile line is associated with aging.
  40. 40. Negative space: Negative space is a dark space appearing between the jaws and the mouth opening either at the corner of the mouth of around the buccal aspect of the posterior teeth during active smile and laugh.The lateral negative space exists between the labial surface of maxillary teeth and the corner of the mouth while the buccal negative spaces appear in the buccal vestibule on either side of the buccal aspect of posterior teeth
  41. 41. Obliteration of these essential spaces by dental elements like bulky canines, wide arches or overcontoured restorations can lead to an unattractive smile. Excessive negative space seen in cases of missing premolars orA palatally placed posteriors and a constricted arch also appear unesthetic.
  42. 42. Progressive abating in a dental composition: When similar structures are aligned in an arch form one after the other, they appear to progressively abate in size from the nearest to the farthest. This gives an illusion of depth. The essential requirement of the front to back progression in dental composition is the alignment of the contour of the labial and surface at the incisal third, middle third and the gingival third of successive teeth in the arch. The incisal mesio-buccal inclines should be well aligned to give a smooth progression from tooth to tooth. The buccal and lateral negative space progressively reduces the illumination on teeth to enhance the front to back abating effect. The presence of poorly shaped teeth, differences in axial inclinations, tooth length discrepancies, discolorations, gingival disharmonies etc. can lead to a visual tension resulting in a disruption of the front to back progression.
  43. 43. Proportion When mathematics is applied to the study of ideal tooth form, a numerical relationship is established within a single tooth form (ideal proportion) and also between a series of teeth in the arch (relative proportion). The position of the tooth in the arch, the relationship between the width, the length and the face of the tooth can also be numerically established in relation with certain anatomic landmarks.
  44. 44. Gold Proportion is expressed in numerical form and applied by classical mathematicians such as Euclid and Pythagoras in pursuit of universal divine harmony and balance. It has been applied to a lot of ancient Greek and Egyptian architecture and may be expressed as the ratio 1.618:1. If the ratio is applied to the smile made up of the central, lateral incisor and the mesial half of the canine, it shows that the central incisor is 62% wider than the lateral incisor which in turn is 62% wider than the visible portion of the canine which is the mesial half, when viewed from the front.
  45. 45. Application of sizing the central incisors from certain facial measurements is known as the 1 to 16 theory, whereby the height of an ideal maxillary central incisor from the incisal edge to the gingival crest is 1/16th of the distance from the inferior border of the chin to the inter papillary line. The same tooth width can be measured from the mesial to distal contact areas and is 1/16th of the distance measured from either zygomatic prominence through an imaginary facial midline.
  46. 46. Once the size for the central incisor is determined it is essential to design its outline form. The facial harmony method can be applied to relate the tooth form to the facial form. Various facial shapes are identified and descriptions such as avoid, square, tapered and combinations of these are used The same shape when inverted can be applied to the central incisor design. This shape acts as guideline for the outline forms of other maxillary teeth.
  47. 47. In an attempt to determine the original anterior tooth placement on the ridge, the position of the incisive papilla is considered as an important land mark as it position does not alter even after bone resportion of the anterior ridge. The distance between the posterior border of the papilla to the outer labial surface of the central incisor averages to about 12.5mm with a variation of approximately 3.8mm. The end of the first palatal ruga is located 1.5 mm to 2mmm from the lingual surface of the canine. Many dentists have also recorded the averages distance between the base of the sulcus and the tip of the maxillary incisor. This distance is measured 22mm. This helps the dentist to determine the tooth position in the vertical plane.
  48. 48. Symmetry For harmony, certain symmetries are essential while certain asymmetries are acceptable. Harmonious facial features should be more symmetrical close to the facial mid line and can be more asymmetrical away from the facial midline. Pleasing Smile A naturally attractive smile that evokes a feeling of beauty or harmony and complements the personality of the bearer is termed as a pleasing smile. The natural pleasing smile may not necessarily comply with all rules of symmetry or golden proportion or may not exhibit perfect balance without irregularity of shape. However, the composition is esthetically appealing with unity within its various elements.
  49. 49. Smile Dominance : Different facial features stand out differently in the eyes of every beholder. In certain cases, the most predominantly striking features of a face is the smile; these are the “Dominant Smiles”. The distinguishing characteristics observed in people with pleasant smile dominance that can be used as a guideline for creating the same are : • The maxillary central incisors exhibit a strong presence by their size and form reflecting the personality of the individual. • The maxillary lateral incisors and the canines complement the cement incisor in terms of proper shape and form.
  50. 50. • Although numerically all proportions of the anterior teeth do not follow the rule of golden proportion, the teeth are so placed that they appear in suitable proportions with each other. • Smile recurring ratios are observed in the teeth from the central incisor to the premolar. • Well co-ordinated movements of the lips with the other peri-oral musculature and corresponding harmonious facial expressions, contribute to the pleasant face during smile. • The complexion and texture on the face contrast with the lip color, gingival and the teeth leading to a distinct demarcation between the oral and the facial frame.
  51. 51. PERCEPTUAL ASPECTS – THE ART OF ILLUSION Illusion is a figment of imagination where a perception of an object is created. Fundamental and Principles The art of creating illusions consists of changing perception, to cause an object to appear different from what it actually is. Teeth can be made to appear smaller, larger, wider, narrower, shorter, longer, younger, older, masculine or feminine. One being subjected to light the most fundamental objects exhibits two dimensions, that is, length and width. True natural light is multi-directional and on striking the surface of the object, also reveals texture and shadows, this adds the third life like dimension of depth.
  52. 52. Illusion works on two basic principles which are the principle of illumination and the principle of light. The most important of these is the perception that light approaches and dark recedes. This is termed as the ‘Principle of Illumination”. The second artistic predilection of great importance in dentistry is the use of horizontal and vertical lines and ridges. Horizontal lines make the object appear wider and vertical lines make the object appear longer. This is termed as the “Principle of Line”. The artistic predilection exhibited in the principle of illumination can be maintained to change the size, shape and the overall form of the tooth through illusions.
  53. 53. Law of the face. The face of a tooth is that area on the facial surface on both anterior and posterior teeth, that is bound by the transitional line angles as viewed from the facial i.e. labial or buccal aspect. These transitional line angles mark the transition from the facial surface to the mesial, distal, cervical and incisal surfaces. The tooth surface slopes lingually in the mesial and distal region while it slopes cervically from the line angles towards the root surface. Whenever there is no transitional line angle demarcating the incisal portion of the facial surface, the face is bound by the incisal edge or the occlusal tip.
  54. 54. Shadows created as light strikes the facial surface of the tooth begin at the transitional line angles, these shadows delineate the boundaries of the facial form. Thus the apparent face is that portion of the face that is visible to the observer from any single view. When maxillary anterior teeth are viewed from the front only the mesial half of the canine is visible however the entire incisor face is visible.
  55. 55. The law of the face implies making dissimilar teeth appear similar by making the apparent faces equal. The apparent face should be manipulated, not the actual face. This is more important in the canines and the posteriors as the ‘apparent face’. The transitional line angles are relocated so that the apparent faces look equal, however this results in dissimilar areas outside the transitional line angles. Similar faces produced attract light and appear high lighted while the dissimilar areas that are in a shadow appear to recede. When the transitional line angles cannot be repositioned on a restoration, then the portion of the tooth can be stained darker to create an illusion that the transition line angle has been moved.
  56. 56. Cosmetic contouring Cosmetic contouring by definition is the reshaping of natural teeth to make them esthetically pleasing. In natural dentitions, variations seen in tooth shape and size some times violate the acceptable width to length ratios as well as the golden proportion. Minor adjustments in contours to change the perception of these proportions increases the esthetic acceptability to a great extent. It is indicated for giving a pleasing appearance to fractured, chipped, extruded, malformed or over lapped teeth
  57. 57. The procedure is contra indicated in hypersensitive teeth, teeth with thin or defective enamel formation or large pulp chambers. The upper lip line should be used as a reference to see how much tooth is visible when the patient smiles. The lower lip line will help to create a pleasing smile line. Tooth visibility with lips at rest, when the patient talks or smiles should also be assessed. The dentist should view the patient in sitting and standing positions
  58. 58. Procedure The procedure involves minimum tooth reduction confined to enamel. Changes on the tooth surface of the related tooth are carried out by working on the transitional line angels, height of contour, incisal and facial embrasures and adjusting incisal edge and angels. Finishing disks are used to open incisal embrasures and the reshaped teeth are then thoroughly polished with a fine grit diamond paste and application of fluoride gel or foam is recommended to minimize any chances of postoperative sensitivity.
  59. 59. ESTHETIC DIAGNOSIS AND TREATMENT PLANNING Total Smile Analysis Total smile analysis is a cumulative inference analysis, drawn by interpreting and integrating various analysis like a visual , space ,profile and computer analysis after performing the preliminary analysis.
  60. 60. Space Analysis It helps the dentist to gauge the amount of space available during the treatment planning stage. The concept is to measure the widths of all the teeth and to compare it with space present in the arch. This determines whether the space available for restorations and natural teeth is less or more than required. Disproportionate spaces may be due to discrepancies in jaw and tooth size, malformed teeth, missing teeth, mal-aligned teeth etc. The space analysis will provide a guideline or a frame work within which the esthetic dentist has to plan each restoration.
  61. 61. Corrections of labio-lingual inclinations and rotations of the teeth by restorative procedures will result in a change in the width space ratio due to the change of angulation involved. It may not be possible to match all teeth on either side of the midline due to space or morphological constraints, but in order to preference they should be matched as far as possible starting from the midline and proceeding towards the canines. Symmetry and dominance of the central incisors being an important element of the pleasing smile should not be compromised as far as possible. For any changes proposed that may involve alterations in the width of the anterior teeth, the law of golden proportion should be closed followed. This enables the esthetic dentist to plan any space manipulations for the restorations in terms of illusions, actual tooth positional changes such as rotations overlaps, spacing etc.
  62. 62. Profile analysis While examining the patients profile, the normal profile is referred to as straight orthognathic. Any deviation from this should be recorded and considered in treatment planning. Examination of the profile could be in the antero-posterior plane or in the vertical plane. If the profile is convex, the features seen include either a normal, increased or decreased lower facial height, a lower lip trap depending on the position of the lower anteriors and deep mento-labial groove.
  63. 63. If the profile is Concave the features include either an increase or decrease in the lower facial height. This may also be associated with a habitual or a pseudo Angle’s Class III relationship. Profile analysis helps in treatment planning of the cases that will require skeletal correction in addition to the esthetic restorations for complete esthetic success. This will ensure that the skeletal and non-skeletal aspects of the treatment plan are segregated and treated for a comprehensive, successful esthetic treatment.
  64. 64. Computer Analysis Radiographs and photographic images have been used as an essential aid in diagnosis, record keeping, communications and treatment planning. Computer aided technology has broadened the scope of applicatiosn as well as enhanced the utility of radiographs and photographs in the dental field. The new intra-oral cameras with digital support and the radio-visiographs are indispensable tools at the esthetic dental office. They give enlarged images of the photographic and radiographic outputs on the screen, without the involvement of any hard copies of photographs or radiographs, with multiple magnifications, and at various angles, for the dentist as well as the patient to assess and view the intra oral condition in a different perspective.
  65. 65. This becomes a handy tool for aiding correct diagnosis as well as a brilliant motivational and communication tool. It is also now possible to do the various facial and profile analysis on the computer screen without hard copies or tracings. With different soft ware applications, the images can be altered for the patient and dentist to appreciate the changes that Computer Analysis
  66. 66. Radiographs and photographic images have been used as an essential aid in diagnosis, record keeping, communications and treatment planning. Computer aided technology has broadened the scope of applicatiosn as well as enhanced the utility of radiographs and photographs in the dental field. The new intra-oral cameras with digital support and the radio-visiographs are indispensable tools at the esthetic dental office
  67. 67. They give enlarged images of the photographic and radiographic outputs on the screen, without the involvement of any hard copies of photographs or radiographs, with multiple magnifications, and at various angles, for the dentist as well as the patient to assess and view the intra oral condition in a different perspective. the proposed treatment modalities may bring about without actually carrying out the treatment.
  68. 68. In a particular case, esthetic enhancement with a change of arrangement, form, shape or color can be demonstrated quickly. Thus computer analysis can be used as a quick reference which can guide the future artistic creations that the dentist may consider, However, the occlusal parameters cannot be addressed without appropriate devices and hence the actual three dimensional aspect of the change cannot be applied without error. Promising the patient results close to what are seen through a computer analysis could lead to dis-satistication and hence the dentist should consider other diagnostic means before designing definitive treatment plans.
  69. 69. ROLE OF TECHNOLOGY IN CHANGING SMILE New technology helps us to preview the end results.The following high tech tools can be incorporated: 1) Extra oral video camera: It allows to have a detailed record of the patient's face while moving and talking- a much more helpful tool than a still photograph. It can record the patient in various moods and gestures and give us the minute details the patient may be unaware of. This can be shown to the patient with the help of computer imaging . Different smiles and profiles can be applied to the patient's face and the patient can be given the opportunity to choose the best smile
  70. 70. 2) Intraoral video camera: It is an easy to use unit designed with reliability, performance and image quality. Intra oral examination from every angle with the smallest details can be viewed as close as 2mm. fron the tooth. With it we can explain certain conditions and treatment options much more accurately than with sketches, mirrors and X- rays. Introral cameras can be integrated with a computer imaging system to capture the detailed images of the patient's oral cavity. These images can be modified according to the proposed treatment options and shown to the patient. At the click of the mouse a particular tooth can be elongated or widened , the effect of which can be shown to the patient for his approval.
  71. 71. 3) Computer or voice activated data Using voice activated technology , we can document our findings by speaking into the microphone that are connected to a computer which has been "trained" to recognise a limited vocabulary. The computer than stores the infomation and even graphics( related to smile ) so that various procedures can be discussed with the patient.
  72. 72. 4) T- Scan and Digital Radiography By using this scan , buccolingual width of the jaws as well as the location of anatomic features such as the mandibular canal and the maxillary sinus can be determined which is useful while placing an implant in the esthetic position. Now-a-days manufacturers promote digital radiography system and video camera in one unit i.e. single hand piece which will be concenient for use.
  73. 73. 5) CAD/CAM With CAD/CAM ( Computer assisted design/ Conputer assisted manufacture) technology we can design veneers and crowns to enhance smile while the patient waits. The so called "mock- up" of a planned cosmetic teatment also has been shown to be quite useful. It also allows clinician to visualise the desired results and solve potential problems before providing treatment to the patient.
  74. 74. 6) Lasers The dental lasre uses a beam of light in place of scalpel to perform delicate gum surgery and crown lengthening/ gingivectomy and gingivoplasty. The advantages of this procedure are1) Controlled bleeding which provides dry operating field and hence excellent visibility. 2) Reduced operating time and reduced post operative swelling, pain and scarring.
  75. 75. 7) Computer Imaging It improves communication between the patient and the dentist by allowing both to visualize , evaluate and agree on treatment. It allows to " see" various looks before deciding upon treatment.
  76. 76. 8) Computer Controlled Injection Technique The P- ASA (Paltal approach anterior superior alveolar ) is a new block injection technique that provides anaesthesia of the maxillary anterior teeth from a single injection without numbness of the face , lips and the muscles of facial expression. The injection can be administered in a comfortable and consistent manner, using a computer controlled local anaesthetic delivery system( the wand). This technique prevents distortion of the smile line and enhances restorative procedures that use the lipline as an esthetic reference element.
  77. 77. 9) Abrasive Technology In this technique , a jet air stream with micro abrasive particles is used to remove the stained areas. It is painless, faster and does not require the use of anesthesia. It can be used in any quadrant for any depth of decay without damaging the healthy tooth structure. After the removal of the stained areas , the tooth structure can be built up with composite. It is also useful during repairs to existing composite or porcelain restorations because it roughens these surfaces allowing the reparative materials to bond them more rapidly .
  78. 78. Occlusal considerations The esthetic dentist has a major challenge in dealing with restorative situations in the mouth where occlusal considerations are critical. Natural and restored maxillary and mandibular teeth should have optimal functional contact relationship resulting in the even distribution of load in static and dynamic positions leading to minimal trauma of the teeth and supporting structures. This requires a thorough understanding of the stomatognathic system which comprises of the temporomandibular joint, the ligaments, related musculature and the dentition and their coordinated three dimensional movements.
  79. 79. Concept of occlusion A thorough knowledge of the various concepts of articulation accompanied with application of the same is mandatory for successful restorative rehabilitation. The various concepts of occlusion are Bilateral balanced occlusion • Group function or unilateral balanced occlusion Mutually protected occlusion
  80. 80. In large or complex rehabilitation’s with fixed prosthesis, a sequential and correct method of recording the jaw relations should be followed since any error would be magnified in the final outcome. This would be detrimental to the survival of the surrounding tissues and the restoration. The hinge axis of the mandible should recorded with a kinematic face bow and transferred to an adjustable. Arbitrary hinge axis face bow is useful for routine work and gives a fairly accurate relationship (error of 5mm). Correct centric relationship and protrusive and lateral inter occlusal records are made in rigid materials and the articulators are adjusted accordingly. Correct incisal guidance is computed and adjusted. This logical and systematic approach ensures minimum error.
  81. 81. Forces on the dentition On the dentition it is influenced by several factors like position of the teeth in the arch, masticatory dynamics, relationship with the opposing arch, crownroot ratio, direction, duration, frequency and character of the forces during functional mandibular movements and parafunctional habits. The peri-oral musculature and the tongue exert a constant force on the teeth. These forces are lighter and in a horizontal direction. Swallowing also exerts forces on a continuous basis throughout the day.
  82. 82. The peri-oral musculature and the tongue exert a constant force on the teeth. These forces are lighter and in a horizontal direction. Swallowing also exerts forces on a continuous basis throughout the day. The heavier natural forces exerted on the teeth are during mastication and are primarily directed perpendicular to the occlusal plane in the posterior region. They are exerted infrequently and for a short duration during the day.
  83. 83. In mutually protected occlusion, where there are no posterior contacts in eccentric movements, fewer fibers of the temporalis and masseter muscles and stimulated resulting in reduction of the forces applied on anterior teeth by two thirds. Research on implant prosthesis and crowns with cast cores on maxillary incisors have shown permissible angle of up to 25° between the crown and root for maintenance of adequate periodontal health.
  84. 84. Parafunctional movements Are identified as a cause for occlusal wear and excessive forces. Parafunction can be related to local factors like malocclusion or to systematic factors like cerebral palsy, epilepsy and can also be stress or occupation related. Bruxism, clenching and parafunctional tongue thrust are the important parafunctions which the dentist should consider in the treatment planning stage. Bruxism Rehabilitation of these cases not only involves elimination of the causative factors but establishment of correct anterior incisal guidance to eliminate all posterior contacts during mandibular excursions.
  85. 85. Clenching : Is the force exerted from one occlusal surface to other without movement. These forces are directed more vertically to the plane of occlusion in the posterior region of the mouth. Fremitus is often found in the clenching patient. This is vibratory type of a force felt with a finger kept in contact with the facial aspect of a tooth while the patients taps the teeth together. It is noticed clinically on many cervically eroded teeth, and if the occlusion is carefully evaluated, it shows signs of excessive forces. This cervical defect is called cervical abfraction. During the management of these cervical defects occlusal adjustments need to be considered along with adhesive restorative methods for a long term success.
  86. 86. Parafunctional tongue thrust : Is an unnatural tongue force which can exert an abnormal horizontal force on the anterior teeth. Esthetic treatment planning and sequencing Treatment sequencing is an integral part of treatment planning. It is a phase wise distribution of treatment procedures which will be programmed or charted considering periods of healing, patient convenience, inter disciplinary treatment modalities and is the fundamental feature of a meticulous treatment execution
  87. 87. Although some basic periodontal, pulpal and temporomandibular problems would be addressed at the initial therapy stage, more definitive periodontal or pulpal treatment may be necessary during the definitive therapy stage. Certain cases involving endodontic posts or implants etc in the esthetic zone may pose a challenge to the dentist in term of giving suitable interim restorations that will not interfere with the healing process.
  88. 88. Mock up Mock ups are made for diagnostic reasons during the treatment planning phase as well as for reference purposes during the treatment phase. For the cases requiring major esthetic correction involving many anterior teeth the dentist can work on the space availability and allotment for every tooth on the mock up even before proceeding for the tooth preparations. A cosmetic preview with the help of composite resins is the easiest and fastest procedure to help the dentist in diagnosis, treatment planning as well as creating references during treatment execution
  89. 89. Composites can be put on the facial tooth surfaces including spaces or even the gingiva to determine the change of position of teeth desired at the final restorative phase. The dentist can show this preview of the patient and get his opinion regarding tooth position, shade, shape etc. The occlusion usually will restrict the restorative ease in many cases. The lower incisors should be thoroughly examined and the contacts of the palatal aspect of the upper teeth marked . The functional movements in the mouth can also be checked at this time to determine any potential occlusal
  90. 90. Obstructions or difficulties that may arise at the time of treatment. Some adjustment in the incisal edges of the mandibular incisors might be mandatory before proceeding with esthetic correction for the maxillary anteriors. In cases requiring reduction of tooth structure like in overlapping teeth, a diagnostic wax-up would be more beneficial as the required reduction of the teeth can be done on the study casts and suitable colored wax-up can be used to visualize the end result and preparation design
  91. 91. In cases requiring closure of spaces and where crown lengthening could be required to improve the width to length ratio of the final restorations, a composite preview could be easily used. Before crown lengthening procedures the extent of gingivectomy and the exact contour to be established on the facial aspect contour to be established on the facial aspect is determined by the location of the gingival zenith after the placement of the final restoration. Hence a composite preview is used to determine the gingival contour and the gingivectomy is performed according to this reference. Once crown lengthening is achieved and after sufficient healing period elapses, composite or ceramic veneer is placed to give the final desired result.
  92. 92. COLOR Dimensions of color Color cannot be perceived without light, which is a form of electoro-magnetic energy visible to the human eye. The visible spectrum of light lies in a narrow band of 380nm to 760nm. It has the ability to stimulate the cells in the retina which is interpreted by the brain, discerning the sense of color.
  93. 93. Clark stated that “Color, like form, has three dimensions”. Hue, which is the name of the radiant energy, Chroma, which is the saturation of the hue and value, which is the relative lightness or darkness of the color. Since clinical color matching depends upon the ability of the dentist to perceive the difference in the tooth shade guide comparison; complete understanding of the color dimensions in critical. The Munsell color order system best serves the needs of the dental profession in its tempt to visualize and organize color.
  94. 94. Hue : In Munsell’s words, “It is that quality by which wwe distinguish one color family from anther”. Generally there are six hue families. Violet, blue, green, yellow, orange and red. For example, in the Vita shade guide there are four hues A, B, C and denoting reddish brown, reddish yellow, grayish and reddish grey respectively. Chroma :In Munsell’s words, “it is the quality by which we distinguish a strong color from a weak one. “Human teeth fall into the yellow to yellow red area of the Munsell color order system. Pale colors have a low chroma whereas intense colors have high chroma.
  95. 95. Value : Value or brilliance is the relative blackness or whiteness of color. On a scale of black to white, white has “high value”, black a “Low value” and Midway between black and white is the medium grey. Value is the only dimension of color that can exist by itself. Opacity and Translucency: As light strikes a surface, it is either totally reflected, totally absorbed or a combination of both. Opaque objects reflect all or most of the light that is incident on them whereas transparent objects transmit all of the light that is incident on them. When part of the light incident on an object is transmitted, while the rest is scattered, the property of the object is known It decreases with as translucency.
  96. 96. Translucency, in effect, is the three dimensional spatial relationship or representation of value. Highly translucent teeth tend to be lower in value, since they allow light to transmit through the teeth, while opaque teeth have higher value. There might be inter tooth as well as intra tooth differences in the translucency. Its extend can vary according to the age of the patient due to the degenerative and reparative changes in the enamel and dentin. To mimic natural teeth the effective use of restorative materials should largely depend upon this translucent effect.
  97. 97. Mechanism The change in color perception of two objects under different light sources is called metamerism. For example , a shade guide tooth matches the natural tooth under incandescent light but not under fluorescent light. This can be attributed to the difference in the radiant energy of two different wavelengths of light. The standardization of lighting condition during hade matching diminishes the effect of metamerism.
  98. 98. Fluorescence The emission of light by an object at a different wavelength from that of the incident light is called fluorescence. The emission stops immediately on removal of incident light. Teeth fluoresce with a stimulus in the range of 340nm to 410nm. This spectrum is in the blue range. Thus, according to the principles of additive color, the emitted blue light acts with the yellowness of the tooth to produce a whiter tooth. Fluorescing pigments incorporated in the ceramic restorations by the ceramist and in the composite restorations by the manufactures may thus be advantageously used in altering the perception of the final result.
  99. 99. Gloss Gloss is an optical property associated with a smooth surface that produces lustrous surface appearance and thus reduces the effect of color differences. Increase the brilliance (value0 of the final result.) In dentistry, unlike spectral colors, the restorative materials have pigment colors incorporated in them. Predictable restorative color outcome can only be achieved by proper understanding of primary, secondary and complementary factors.
  100. 100. Primary color Are those colors that cannot be formed by mixing of multiple colors. They occur naturally by themselves. For example, red, yellow, blue etc. Complementary colors According to the additive principle of colors, complementary colors can be used to lower the value of the restoration and not to complementary color may be added to the respective hue to decrease the value.
  101. 101. Perception of color. The perception of color involves many physiological , physiological and physiological aspects The light source. The light source has the color of the emitted light and is described in color temperature (Kelvin.). The lighting environment makes a significant differences in the perception of color. The teeth and the shade guide should be sufficiently illuminated. The light reflected from a glossy surface obscures the viewer’s perception of light. Shadows should be eliminated as they reduce the available light and hide details.
  102. 102. The dental operator maybe illuminated by combination of natural sunlight and artificial light, The artificial light may be incandescent (predominantly) blue. Also the ratio between the task light (which falls directly on the working area) and the ambient light (derived from the surroundings), known as the contrast ratio, should be higher than 3:1, but lower than 10:1. This can be attained by regularly measuring the intensity of light, cleaning the diffusers and the light sources any by replacing them when their effective life is over.
  103. 103. The observer The stimulus of light travels through cornea, lens, aqueous and vitreous humors and reaches the cones and rods of the eye. The cones function for day light vision and color perception whereas rods are sensitive to the quantity of light perceived. These stimuli are then sent to the brain, where they are computed and interpreted as color. This complexity of color is further modified by the embryonic development of the brain, aging process, aberrations of color vision like color blindness, dichromatism, mental fatigue and drug intake.
  104. 104. The object The quality of the color of an object (the tooth) depends on its ability to absorb, reflect, transmit or refract the light energy falling on it. The surrounding environment greatly influences the color. The ceiling and the walls reflect light and should not be pained in bright colors. Neutral colors like grey or white should be selected. Contrast effects The background considerably affects the perception of color. Different contrasts effects that alter the color vision, should be understood.
  105. 105. Simultaneous contrast Is visualized when two objects are viewed at the same time. The light or dark contrast can be correlated to the surrounding environment like skin tone, hair color and brightness of adjacent soft tissues and teeth. Hence, brighter shades should be chosen for light toned patients and darker shades for pigment toned patients. Actual contrast Is influenced by the size and the chroma of the tooth. A brighter tooth looks larger while a darker tooth of the same dimension look smaller.
  106. 106. Shade selection Shade selection is a complex procedure due to the variations and differences in the optical properties of the new generation of cosmetic restoration materials. It can be well accomplished by understanding the fundamentals of color and adopting a proper methodology of matching shades. The effective communication with the laboratory and precise fabrication and meticulous finishing of the restoration will affect the color of the final restoration.
  107. 107. Shade selection sequence Any color modification procedures like bleaching or microabrasion should precede color selection after ensuring color stabilization. • Make the shade selection at the beginning of the procedure as well as over different appointments (diagnosis, prophylaxis etc.)and cross check these observations. • View the patients at eye-level. The operator should stand between the light source and the patient. • In a contrasting environment, colors look more intense and brighter. Hence it is wise to ask the patient’s to remove artificial lip color.
  108. 108. • Place the tabs as close as possible to the area that is being checked. • Moisten the tab and eliminate the worst match. • Evaluate the value (upper to lower). Value is the most important factor in shade matching. If the value blends, small variation in hue and chroma will not be noticeable. The value is to be matched with eyes half closed. • After value, mark the translucency • Match the chroma (more or less saturated) and finally, hue in that order.
  109. 109. • To avoid hue sensitivity, rapid observation is made for 5 seconds (not more than 20 seconds). Look away, ideally stare at a blue surface, which will readapt the vision to the orange yellow portion of the spectrum. • Match prior to tooth preparation, since preparation dehydrates and changes color due to the debris of preparation. • Match the tab with the opposing tooth also. Metamerism complicates color matching, as the tabs look different under different light sources. The best approach is to use three light sources; cool white fluorescent light, incandescent operatory lamp and day
  110. 110. • When in doubt, always select higher value and lower chroma, since it is easy to lower value and increase chroma • Shade tabs of different batches don’t always match, hence it is wise to sent the actual selected shade tab to the technician. • Make a decision regarding relative translucency, area of hypo calcification, increase saturation, crack lines surface texture and other characterization. Make a drawing of the facial surface and record all patient information graphically.
  111. 111. Dental Bleaching Bleaching is one of the most commonly sought elective dental procedures to brighten a smile. It is a simple, fast and effective treatment to change darker tooth shades into lighter ones. Chemistry of bleaching Bleaching process is based on the oxidation of bleaching agent. Oxidation is the chemical process by which organic materials are converted into carbon dioxide and water. The oxidation reduction reaction that takes place in the bleaching process is called the redox reaction.
  112. 112. Bleaching slowly transforms the organic substance in the stained tooth into chemical intermediates that are lighter in color than the original tooth shade. In a redox reaction the perioxide (oxidizing agent) has free radicals with unpaired electrons, which it gives up, becoming reduced. The stained tooth structures accepts these electrons and becomes and oxidized, thereby reducing the organic colorants. The free radicals produced by the peroxides are perhydroxyl and nascent oxygen. Of these, the perhydroxyl is a more potent free radical which is responsible for a better bleaching action.
  113. 113. In order to promote the formation of perhydroxyl radicals, the peroxide is buffered to a pH range of 9.5 to 10.8. The buffering provides a greater amount of perhydroxl radicals, which results in a better bleaching effect. The most common bleaching materials used are hydrogen and carbamide peroxide. Carbamide peroxide first breaks down into hydrogen peroxide which then further liberates the above mentioned free radicals. Unlike the hydrogen peroxide, the carbamide peroxide bleaching agent must remain in contact with the teeth for a longer period of time to obtain complete efficiency of the reaction. Carbamide peroixde is less irritating to the gingival tissues thus better tolerated by the patients when used as a home bleaching agent.
  114. 114. Mechanism of bleaching In the presence of moisture as well as surface debris on the tooth, the ionization by hydrogen peroxide occurs by decomposition into water and nascent oxygen which is a weak radical making the peroxide which is a weak radical making the peroxide inefficient as a bleaching agent. Hence, it is important to have teeth dry and free of surface. Increase in the temperature, higher peroxide concentration and the duration of exposure of the tooth structure to the peroxide within limits, direct affects the oxidation process leading to a greater degree of color change.
  115. 115. Saturation Point Prolonged used of a bleaching agent causes the whitening action to slowdown beyond a point during the treatment. This is the saturation point. The bleaching if allowed to continue, begins to break the inorganic structure from the enamel becomes rapid. Bleaching should thus be stopped at or before the saturation point. If bleaching is done beyond the saturation point, it clinically manifests an increase in porosity on the tooth surface. A fluoride application is recommended and no bleaching agents should be applied allowing the enamel to remineralise.
  116. 116. Procedure for bleaching Use of concentrated heroine or carbamide peroxide solution available in standard 35% concentrations. In a technique described as ‘assisted office technique’, 35% carbamide peroxide is tray loaded for 45 minutes, after following required protocols. Some bleaching materials are available in a combination of a hydrogen peroxide and carbamide peroxide in 20% and 16% concentrations respectively. There are other “dual cure” systems, which initiate the bleaching reaction on the tooth surface through a chemical reaction which is catalyzed through light activation by a visible blue light spectrum.
  117. 117. Preparation of trays The bleaching procedure is recommended for the number of teeth seen in the patients active smile. 1 millimeter reservoir for the bleaching gel. On the modified cast soft and clear vacuuform matrix of 0.035”thickness is made. The matrix, carefully trimmed to cover only the clinical crowns. Contract the bleaching gel with marginal gingiva may result in tissue irritation hence vacuuform trays should have a marginal seal to eliminate contact of the caustic bleaching gel with the gingiva.
  118. 118. Isolation of teeth Proper isolation of area with cotton rolls or rubber dam is mandatory. The gingival surface is wiped and dried sufficiently. Etching of tooth surface Each tooth is etched on labial surface for 10 to 20 seconds using 32% - 37% orthophosphoric acid. This step removes any superficial surface stains and enhances the penetration of the bleaching solution into the tooth surface producing a greater stain reduction. Excessive etching causes the demineralization of the enamel matrix, leading to surface irregularities and causing sensitivity.
  119. 119. Application of bleaching material The bleaching materials is slowly loaded in to the vacuufrom trays so that it spreads all over the labial surface of the teeth to be bleached. The trays are kept in place for an average duration of 30 minutes depending on the type of material used and the manufactures recommendations. Micro-finishing and polishing Following bleaching, the teeth are microfinished using fine abrasive disks. Final polishing is done with aluminum oxide or fine grit diamond polishing pastes.
  120. 120. Office bleaching of non vital teeth The two most commonly used agents for bleaching of non-vital teeth are hydrogen peroxide and sodium perborate. Home bleaching Bleaching may be carried out at home by the patient. The home bleach technique involves the application of bleaching agent through the use of vacuuform trays. The frequently used bleaching agent is 10% - 15% carbamide peroxide.
  121. 121. Bleaching in relation to bonded restorations It was determined in clinical studies that the bond strength of composite to enamel is reduced when the tooth is bleached. The primary cause for the reduced bond strength is the presence of the residual peroxide or oxygen, which interferes with the polymerization of resin bonding systems and restorative materials. Any bonded restorations in the bleached teeth need to be done after a period of two weeks. If bonding cannot be delayed by two weeks then the enamel should be roughened and acetone based adhesive system used.
  122. 122. Enamel microabrasion Hydrochloric acid *18%) pumice abrasion can remove white enamel opacifiers, multicolored defects and many brown, orange, yellow enamel spots and streaks, regardless of etiology. These stains can be eliminated with insignificant enamel loss if the stain is limited to a thin layer of tooth surface (approx. 0.5mm). This procedure can be used independently or prior to bleaching to give optimal results.
  123. 123. Management of Fluorosis stained teeth A solution of anaesthetic either, hydrochloric acid and hydrogen peroxide may also be used for bleaching teeth with fluorosis stains. The anaesthetic either removes surfaces debris, the hydrochloric acid etches enamel and hydrogen peroxide bleaches it.
  124. 124. Esthetics with composites Considerations in preparation design for anterior teeth. The preparation design for anterior composite restorations should encompass elimination of decay, function and longevity, and esthetic predictability. Function and longevity A pre-operative analysis of the occlusion is crucial to determine the palatal extensions and the acceptable length in upper anterior restorations.
  125. 125. . Checking the lateral and protrusive excursions will given an ideas as to how far palatally the final restoration can be placed. Researchers have found that a minimum of 1.5mm – 2mm of the composite thickness is essential to give sufficient strength to the material. A conscious effort has to be made to leave at least 2 mm of composite thickness at the margins for good marginal adaptation and retention in larger restorations.
  126. 126. Esthetic predictability After elimiantion of the decay and determining the extent of preparation required for function and longevity , the preparations are evaluated and if required redefined. The preparation design is extended to allow a smooth transition of shade from the composite restoration to the rest of the tooth. This enables the restorations to achieve esthetic excellence. To create proper tooth from, shape, shade and texture, and to optimize function, all cavity preparations designs should have extension for function and esthetics (EFE).
  127. 127. The EFE ensures that the margin of the restoration overlays the defects. The esthetic advantages are : • Successful masking of the defect • Better marginal adaptation • Natural transition of shade between composite and tooth • Ease of finishing and texturing
  128. 128. EFE and placement of composite for malaligned teeth The preparation in malaligned teeth is a typical and depends upon the degree of rotation and angulation exhibited by the teeth and hence a uniform layer of composite cannot be placed to treat such teeth. The effective use of opaque composites in areas having no tooth or thin palatal structure, improves the blending of the restoration. Creating surface characteristics and effectively placing the transitional angles on the facial surface can help to over come deficiency in tooth reduction.
  129. 129. EFE and placement of composite for closing spaces Diastemata may be manifested to due to microdontia, discrepancy between tooth size and the available ridge and also due to variation in the tooth morphology. Although some natural spaces may be esthetically and phonetically acceptable, others are not and need corrective restorative procedures. However, in cases where the size of the teeth is normal and a diastema still exists, restorative creations using principles of illusion is recommended.
  130. 130. When a diastema is small up to 2mm, no tooth preparations is required. The minimal thickness of composite can be adequately shaped especially at the cervical region to allow good maintenance. However, in cases of a moderate diastema between 2-4mm the EFE should be given on the proximal curvature of the labial surface of the tooth. The extension preparation is close to the gingival margin and follows the contour of the inter dental papilla to end on the palatoproximal line angle. The preparation is in the form of a depression, which provides a definite stop and is done with a chamfer bur.
  131. 131. The preparation design ensures adaptation of sufficient bulk of the composite at the gingival margin creating contours favorable for gingival health. The labial extension allows smooth blending at the composite tooth interface while the palatal extension provides stability and retention. In cases with diastemata larger than 4mm a similar preparation coupled with recontouring of the other proximal surface of the tooth to maintain tooth proportions and form may be required. Diastemata are filed in one tooth at a time. A celluloid matrix is effectively used to get the desired contour
  132. 132. EFE and placement of composites in cervical defects Cervical defects are caused due to caries, abrasion, erosion or abfraction and a combination thereof. Although management of these defects involves similar procedures, their proximity to the gingiva makes it difficult to restore. Before any preparation, a gingival cord is placed in the sulcus to allow a proper access to the defect and to keep away sulcular fluid or blood from the cavity margins. Since bond strengths with the cementum are weak, no additional bevel is recommended at the cervical region in cases where the base is in the cementum.
  133. 133. A round bur is used to roughen the surface of the cavity and a long bevel is placed on the occlusal edge of the cavity. After etching, the cord ischanged and bonding adhesive is applied followed by flowable composite which is used as an intermediate layer. The gingival cord is removed after completion of the filling to facilitate finishing and polishing. The occlusion is adjusted, especially eccentric contracts, to take care of primary or secondary abfractions. Fine diamonds or carbides are used to finish the margins.
  134. 134. Tissue management Success of composite restorations depends not only on preparation design, bonding procedures, quality of restorative material and skill of the dentist but it also largely dependent on the thoroughness of the isolation. The greatest challenge involved in creating predictable composite restorations near the gingival margins is to achieve hemostasis and control of sulcular fluid. Therefore, tissue management becomes an integral element of these procedures.
  135. 135. In case of contamination of composite by blood, blood pigments containing iron or ferric sulphate migrate between the composite and tooth surface or between different layers of composite. These pigments turn dark and are visible as a black-brown discoloration in the restorations. Salivary contamination as well as crevicular fluid ingress in the preparation can cause bonding failures at these areas leading to the failure of the restoration.
  136. 136. Retraction cords displace the gingiva and keep blood and suclurlar fluid away allowing proper access with contamination during placement and finishing of composites. In cases where the cavity design is close to the gingival margin, double retraction technique can be effectively used. Astringent impregnated cords should be used with caution as nay residual astringent can potentially contaminate the tooth surface to be bonded causing a bonding failure.
  137. 137. Shade matching Shade selection is done following standard protocol with references to the incisal third, middle third and the cervical third of the tooth. The uniqueness of composites permits pilot shade test to reconfirm shade attributes before final restorations. The pilot shade test is carried out using a selected shade in a bulk of 1.5mm- 2mmon the involved tooth and a contra lateral or guide tooth. The composite is then cured and finished and the accuracy of the shade match is confirmed. Any changes in the value, transluency and chroma is recorded and the shade is changed if required.
  138. 138. Three procedural steps for finishing and polishing • Gross reduction, contouring , defining the margins. Fine grit diamond abrasive or tungsten carbide finishing bur can be used for the these purposes (100µm size abrasives) • Intermediate finishing is used to reduce scratches left by gross reduction and to blend all surfaces with each another keeping the orientation of various facial planes intact (less than 100µm but morethan 15-20 µm particle size). • Final abrasive polishing imparts enamel like effect on the restorations. Loose abrasive devices, disks, pastes with particle size less than 20µm is used.
  139. 139. Esthetics with Ceramics Ceramics laminate veneers In 1930 Charles Pincus used a unique procedure to improve the smiles of certain Holly wood actors. This technique was non-invasive and gave good esthetic results with resin and air fired ceramics. But the veneer coping made then lacked permanent retention and later this technique was discontinued.
  140. 140. Considerations in tooth preparations for ceramic laminates Tooth preparation design will depend upon the existing color of the teeth, whether change in alignment or an increase in height of the final restoration is sought. When a mild to moderate discoloration has to be masked the preparation can be minimal from 0.3mm cervicaly to 0.5mm at the incisal edge. Whenever a severe discoloration has to be masked the preparation has to be deeper to allow more die spacer to be applied on the model. His excessive space allows use of resin curing cement to mask the severe discoloration. Adding more opaque ceramic in the veneer will mask undesirable tooth color but will limit the display of vitality.
  141. 141. A more translucent ceramic will allow more light transmission and reflection internally making the restoration more vital. If change in alignment is indicated then more preparation will be required in certain areas. When length of the veneer has to be increased a palatal extension is recommended.
  142. 142. Preparation of maxillary teeth for ceramic laminates • Mock preparation on the pre-operative casts and diagnostic wax up gives valuable information about he amount of tooth preparation and helps to visualize the end result. • Local anesthesia may be required when the preparations reaches the dentin and to facilitate easy gingival retraction procedures.
  143. 143. • Self-limiting three-tiered depth cutting burs of known dimensions (0.3mm and 0.5mm) facilitate repaid, adequate and conservative tooth reduction. The depth roves are made by moving them on the facial surface from the mesial to the distal and by changing the angle of the bur to facilitate their orientation in two planes (Fig. 8-1a). Then the facial reduction is achieved following the labial contour of the tooth till the depth grooves. Besides, the contralateral tooth can be used as a reference to check adequate tooth preparation. Selective labial tooth preparation is required to create a favorable arch form.
  144. 144. • A modified chamfer margin is preferred to allow distinguishable finish line in the impression, definite seat and adequate bulk for laminates. The margin is usually supra-gingival or equip-gingival. The margin is taken intra-crevicularly in certain cases to mask the underlying discolored tooth and cover cervical lesions. • The proximal finish line is placed into the embrasure area to ensure that the margin between the laminate and the unprepared tooth structure is well hidden. Deficient preparation reveals unaesthetic margins proximally.
  145. 145. • Incisal preparation depends on whether an increase in tooth height is required or not. In case where the increase in not sought, the incisal preparation ends midway between the labio-lingual width of the incisal edge. A facio-incisal angle of 30 o with a definite stop (window preparation)is given. Butt joints are rarely recommended . In case when the length of incisor is to be increased, the incisal table is flattened with a bevel of 45 o palatally. The palatal preparation is a wrap-around design with the margin placed inferior or superior but never at the contact of the mandibular incisor in centric occlusion
  146. 146. • Similarly, window preparations are advocated for canines and premolars when increase in height in not required. • When the length has to be increased, the anterior and lateral guidance has to be considered and appropriate tooth preparations has to be carried out to allow for adequate thickness of the laminate at the incisal or occlusal area.
  147. 147. Provisionalization of laminates Good provisional help in visualizing the final outcome and can give adequate information of the shade and shape of the laminate to the patient and dentist. Making and placing provisionals for laminate preparations is made tedious than provisionals for crowns. Due to the poor strength of the thin provisionals, there is a possibility of breakages during removal and inadequate luting strength.
  148. 148. There are various methods of making provisionals for laminate preparations. Composite resin is directly sculpted on the prepared tooth after spot etching and bonding at the center of the tooth and cured to get esthetically acceptable provisionals. This technique is simple, comparatively less time consuming and cost effective than others. Another technique involves making a vocuum formed shell of clear plastic sheet on a preoperative cast. The shell with light cured resin is then placed against the prepared teeth. After the composite is cured, the shell is separated and finished provisionals are luted to the preparations.
  149. 149. Try in Chair side try-in is done to check individuals veneer fit, collective fit of veneers and the shade of the composite luting cement that should be used to get the desired final result. Individual veneer is tried for marginal fit, adaptation and retention. Any premature contacts are relieved at this stage. The veneers should fit in passively with good contacts and not actively as it may lead to displacement of some veneers .
  150. 150. Cementation The patient is viewed periodically for the gingival response and maintenance regimen. Usually a 3month check up followed by a 6 monthly check up is recommended. Metal ceramic and all-ceramic restorations Metal ceramic and all ceramic restorations have excellent esthetic potential. The metal ceramic restorations owe their popularity to the simplicity of bridge construction, durability, strength, marginal adaptation and versatility of use.
  151. 151. Can be used successfully for various complex clinical situations like long span bridges, full mouth rehabilitation as also a number of semi-fixed type of appliances. All ceramic restorations are characterized with a dentin like core which makes it possible to mimic the translucency of natural teeth. They are biocompatible with the gingival tissues and exhibit excellent marginal fit due to newer thermoplastic processing while some exhibit wear resistance similar to that of enamel. All ceramic restorations are indicated for crowns, veneers, inlays, onlays and three unit bridges with the premolar as the distal most abutment.
  152. 152. Although all anterior teeth were esthetics is a prime concern can be indicated for all ceramic restorations, caution has to be taken when a parafunction, exists, when tooth structure is insufficient to support the ceramic, in short clinical crowns and when the lingual preparations is thinner than 0.8mm. In such cases a metal ceramic restorations is functionally stable and indicated.
  153. 153. Imperatives of tooth preparations • Length and taper of the preparation for retention and resistance. • Enough reduction to allow thickness of the ceramic for excellent esthetics. Occlusal clearance for occlusal function and anterior guidance.
  154. 154. Tooth preparations for metal ceramic crowns. The incisal edge reduction of 1.5mm – 1.8mm and the occlusal reduction of 1.5mm – 1.7mm with functional bevel is recommended . Reduction is achieved by using a wheel diamond on the incisal edge or a round diamond of known diameter in the occlusal grooves. The incisal edge reduction is followed by the labial reduction. When reducing the labial surface of the tooth, the exact contour must be emulated. This helps to prevent excess removal of tooth structure which may lead to deficient lingual wall preparation especially at the incisal aspect. The labial reduction is achieved in two planes with a round-ended tapered bur, the first orientation involves the incisal two thirds of the tooth.
  155. 155. The palatal reduction is carried out allowing sufficient space for the crown and to re-establish normal occlusal and protrusive relationships. A pear shaped or rugby diamond is used to reduce the lingual concavity while the rest of the cingulum surface is reduced with a round ended tapered diamond bur. The proximal reduction involves smooth movements from the labial surface to the palatal allowing is finished margin on the proximal surface. Long tapered fissures can be initially used followed by round ended fissure burs to achieve desired reduction. Preparations must include 1mmm peripheral shoulder or chamfer with bevel for ceramometal crowns. The objectives is to achieve a convergence angle of the axial walls in the range of 6o to 100.
  156. 156. A shoulder with a 90o cavo-surface angle or a stopping shoulder of 120o is recommended for a adequate support of porcelain. When the metal margin is shortened for esthetic reasons, shoulder porcelain requires 1.2mm of tooth reduction at the margin. The shoulder with a long bevel is advocated for improved marginal fit but it cannot be accommodated in shallow gingival sulcus. Hence short bevel of 0.5mm with a cavo-surface angle of 135o is preferred.
  157. 157. Chamfer (0.5mm)is the finish line of choice for metal backing. For porcelain fused to metal backing, a metal collar on a modified chamfer is preferred. The palatal chamfer is blended smoothly with the labial shoulder lingual to the contact area for good esthetic results. All sharp line angles within the preparation should be rounded to reduced stress concentration.
  158. 158. Tooth Preparation for all ceramic crowns. Although the preparation sequence for all ceramic restorations is similar to the metal ceramic one, the main concern for the dentist in the preparation for the all ceramic crowns should be to minimize the stresses that could be incorporated on the ceramic in function. The length of the preparations is important as load applied from a lingual direction on a short preparations can lead to severe compression of the labial shoulder leading to a fracture. The incisal edge is reduced to get flat area however a reduction in excess of 3mm is avoided. In some cases a reduction of up to one third of the crown height may be required to get rid of the thin incisal edge. The facial reduction planes at a depth of achieved in two 1mm to 1.5mm.
  159. 159. The lingual aspect should be shaped to remove any uneven surface or sharp line angles and should incorporeated or sharp line angles and should incorporate a definite lingual concavity with a high lingual axial wall whenever the cingulum prominence and occlusion is favorable. Lingual depth should be 1mm – 1.5mm and should not be less than 0.8 mm. The proximal preparation is completed with a taper of 6o-8o and will help in one path insertion. Excessive taper will cause inadvertent forces on the ceramic and leads to reduction in flexural strength.
  160. 160. The facial reduction, lingual reduction and the proximal reduction should end into a well defined shoulder. The shoulder should not create any undercuts for the restorations and hence any angle in excess of 90o should be avoided. The shoulder should not necessarily be uniform labially, proximally and lingually, as excessive reduction may be required to do so, compromising on the resistance and retention form of the preparation. The shoulder is usually 0.8mm – 1.0mm wide in the labial and lingual and 0.5mm – 0.6mm in the proximal aspect where the ceramic flares to give sufficient strength. The smooth finish line should not be steep inter proximally but have a smother gradient to avoid potential stress area during function.
  161. 161. As a compared to the preparation for metal ceramic restorations, the finish line for all ceramic restorations should be a shoulder which is at right angles to the direction of stress thus increasing the fracture resistance. In the final preparation all sharp line angles and undercuts are avoided providing maximum strength and resistance. Adequate length of the preparation is required in order to counter the tipping forces and increase the surface area for additional retention.
  162. 162. The depth of the facial and lingual shoulder should be 1.0mm (with a minimum of 0.8 mm) and interproximally the shoulder can be 0.5mm as the restoration flares interproximally. A taper of 5o 10o is advisable for conservity and increased support to the restoration. Increased taper leads to stress concentration in areas where the support is lacking.
  163. 163. Try-in All metal castings are evaluated for margin integrity, internal fit, stability and adequate space for ceramic material. Intra occlusal relationship record is needed in extensive rehabilitation cases. Bisque trial for ceramic restorations are assessed for location, site and tightness of proximal contacts, marginal adaptation and favorable centric and eccentric occlusal contact without interferences. Besides the shape, contours and color; adequate surface characterization is checked and incorporated. The trial for all ceramic restorations are assessed for a passive fit, margins, proximal contacts, stability, shade, form, characterization and occlusion.
  164. 164. Pre-implant esthetic consideration In cases of anterior implants in the esthetic zone, certain specific esthetics criteria have to be considered. When esthetics is the prime reason for seeking implant prosthetic treatment, the patient’s upper lip line will be of extreme importance for the planning of the definitive superstructure. In patients with a high lip line or requiring upper lip support from the prosthesis a removable over denture will more likely fulfill the demands of function and esthetics than an implant borne bridge construction.
  165. 165. The single tooth anterior implant situations is of great concern as the esthetic requirements and expectations have to be properly balanced keeping in mind anticipated post-surgical results. The dentist should analyze anterior single tooth implant situations considering the adjacent teeth, contra-lateral tooth, probable emergence profile and presence or absence of inter dental papilla when ever the active smile exposes enough of gingival tissues.
  166. 166. There are many limitations and contra indications specific to the maxillary single tooth implant apart from the routine contra indications associated with implant therapy. The common causes of a missing maxillary tooth is traumatic loss, root fracture, agenesis and periodontal disease. All these leave some deficiency in the facial bone over the root of the missing tooth. Majority of the cases of maxillary single tooth implant in patients with high upper lip line require bone grafting for ideal esthetics while in some cases bone grafting would be necessary to provide adequate healthy peri-implant soft tissue to maintain optimal hygiene in the cervical region.
  167. 167. There are many limitations and contra indications specific to the maxillary single tooth implant apart from the routine contra indications associated with implant therapy. The common causes of a missing maxillary tooth is traumatic loss, root fracture, agenesis and periodontal disease. All these leave some deficiency in the facial bone over the root of the missing tooth. Majority of the cases of maxillary single tooth implant in patients with high upper lip line require bone grafting for ideal esthetics while in some cases bone grafting would be necessary to provide adequate healthy peri-implant soft tissue to maintain optimal hygiene in the cervical region.
  168. 168. Apart from the inadvertent deficiencies in the facial bone associated with various clinical situations, the soft tissue form also plays a major role in the esthetic outcome of single tooth implants. In 1989, Misch reported 5 prosthetic options available in implant dentistry. The first three options are fixed prosthesis (FP). The next two options are removable prostheses (RP).
  169. 169. Prosthodontic classification Type Dentition FP – 1Fixed Prostheses, replaces only the crown, looks like a natural tooth. FP – 2Fixed Prostheses, replaces the crown and a portions of the root; crown contour appears normal in the occlusal half but is elongated or hyper contoured in the gingival half. FP – 3Fixed Prostheses ; replaces missing crowns and gingival color and portion of the edentulous site; prostheses. Most often uses denture teeth and acrylic gingiva, but may be porcelain to metal.
  170. 170. RP – 4 Removable prostheses ; over denture supported completely by implant. RP – 5 Removable Prostheses ; over denture supported by both soft tissue and implant. Fixed Prostheses FP-1 – FP-1 is a fixed restorations and appears to the patient to replace only the anatomic crowns of the missing natural teeth. There usually has been minimal loss of hard and soft tissues. The final restorations appears very similar in size and contour to most traditional fixed prostheses used to restore or replace natural crowns of teeth.
  171. 171. FP –1 prostheses is most often desired in the maxillary anterior region. However the width and / or the height of the crestal bone is frequently lacking, augmentation is often required before implant placement to achieve a natural looking crown in the cervical region because there are no inter dental papillae in edentulous ridges, gingivoplasty is required after the abutment is positioned to improve the interproximal gingival contours. Ignoring this step causes open “back” triangular spaces (where papillae should usually be present) when the patient smiles. The bone loss and lack of inter dental soft tissue complicates the final esthetic results, especially in the cervical regions of the crowns.
  172. 172. FP-2 fixed prosthesis restores the anatomic crown and a portion of the root of the natural tooth. The volume and topography of the available bone dictate a deficient vertical implant placement compared with the FP-1 prosthesis, which is more apical compared with the cemento-enamel function of a natural root. As a result the incisal edge is in the correct position, but the gingival third of the crown is over extended, usually apical and lingual to the position of the original tooth. If the high lip line during smiling or low lip line during speech are favorable and do not display the cervical regions, the longer teeth are usually of no consequence. FP-2 prosthesis that are not hidden by lip position during smiling or speech can be solved by using a removable soft tissue replacement device.
  173. 173. The FP-3 is a fixed restorations that appears to replace the natural teeth crowns and a portion of the soft tissue. As with the FP-2 prosthesis, the original available bone height loss decreased by natural resorption or osteoplasty at the time of implant placement. To place the incisal edge of the teeth in proper position for esthetics, function, lip support and speech, the excessive vertical dimension to be restored required teeth that are unnatural in length. The patient having high maxillary lip line during smiling and low mandibular lip during speech, will display the longer teeth which look unnatural. In the AP 3 the restored gingival colour and contour give the teeth a more natural appearance in size and shape and mimic the inter dental papilla region. The addition of gingival tone acrylic or porcelain for a more natural appearance is often indicated.
  174. 174. RP-4 It is a removable prosthesis completely supported by implants and or teeth. It may draw the same appearance as an FP-1, FP-2, FP-3 restorations. RP – 5 It is a removable prosthesis combining implant and soft tissue support. The prosthesis is very similar to traditional over denture
  175. 175. Factors for favorable implant placement The physiologic limits with in which the implant can be placed are governed by the following • The space between implant and periodontal ligament of the adjacent tooth should be 1mm. • The average width of periodontal ligament is 0.25mm.
  176. 176. These natural periodontal components will require a space of 1.25mm on either side of the implant. Thus, mesiodistally the implant diameter is added to this minimum space required. The facio-lingual requirement. For a 3.5mm implant placed in the anterior region a minimum of 6mm of space mesio-distally has to exits to accommodate all related components. Ideally, the ridge should be 56mm wide labio lingually, to allow at least 1 mm of the cortical bone labially and lingually. However, to impart esthetics in the inter dental papilla region, the distance between an implant and natural teeth is kept 2mm.
  177. 177. The implant should be 3mm apical to the gingival margins of the adjacent teeth. Labio-lingual orientation of the implants helps to achieve desired emergences profile. Placing the implant slightly palatally helps the dentist to build up a proper emergence profile to the crown. To obtain satisfactory peri-implant gingival morphology, tissue volume should be 20-25% more than the estimated need to allow adaptation of gingiva to the prosthetic reconstruction.
  178. 178. Wider diameter implant will ease the transition of the implant head to the artificial crown as it emerges from its soft tissue housing. The wider diameter implants will not be required to be placed far apical to the cemento-enamel junction of the adjacent tooth. Immediate implants help to preserve the hard and soft tissues, and maintain the emergence profile as in natural teeth.