Fundamentals of cavity preparation /certified fixed orthodontic courses by Indian dental academy


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Fundamentals of cavity preparation /certified fixed orthodontic courses by Indian dental academy

  6. 6. INTRODUCTION CAVITY: Refers to a defect in enamel, or enamel & dentin, resulting from pathologic process- DENTAL CARIES Once caries process invaded-Frank cavitation Effective treatment for preventing further progress - complete removal of affected
  7. 7. Cavity preparation accomplished in an orderly sequence meant to serve as a guide not as hard-&-fast list of directives rationale for development of cavity preparation inter-related steps & mutual
  8. 8. CAVITY PREPARATION defined as the mechanical alteration of a defective injured or diseased tooth in order to best receive a restorative material which will re-establish a healthy state for the tooth including esthetic corrections, along with normal form and
  9. 9. Performance of dental surgical procedures, require to expose carious lesion, permit removal of affected dentin & enamel as to contribute to biologically & mechanically sound restoration Mechanical preparation &/or chemical treatment of remaining tooth structure, which enables to accommodate restorative material, without incurring mechanical or biological
  10. 10. HISTORY Archaeological evidence of dental treatment from 5000 BC 1800 early drills by hand 1955 Page-chayes handpiece-first belt driven angle handpiece 1957 Borden airotor handpiece-first clinical air-turbine handpiece airmotor, electric micromotor, straight handpiece, right-angled handpiece air abrasion, lasers -
  11. 11. 9th century cavities prepared for inlays cavity preparation techniques known for centuries 19th century Hamelton Jameson first emphasized the organized cavity preparation removal of soft & infected dentin-hand instruments sterilize dentinal surface retention form- dentinal buttons Charles E Woodbury- labial margin preparation in harmony with lines of refraction of labial
  12. 12. Henry A Time - slant technique Extension for Prevention - Marshall Ebb & G V Black Charles E Woodbury, E K Wedelstaedt, Walton I Ferrier , George Hollenback 1930 G V Black- systemic approach to cavity preparation Simon -6th classification 1998 G J Mount
  13. 13. OBJECTIVES OF CAVITY PREPARATION remove all defects-protection to pulp locate margins of restorations as conservative as possible form cavity- withstand under force of mastication tooth/restoration allow esthetic & functional placement of
  14. 14. repair a tooth after destruction from a carious lesion replacement and repair of restoration with serious defects restore form & function • fractured teeth, congenital malformation, esthetic
  15. 15. FACTORS AFFECTING CAVITYPREPARATION GENERAL FACTORS  PATIENTS FACTOR diagnosis economic status prevention age interception choice of material preservation
  16. 16. CLASSIFICATION G V Black’s classification Modifications of G V Black’s classification Graham J Mount Vimal K
  17. 17. G V BLACKS CLASSIFICATION  Firstclassification  universally accepted  based on type of treatment & areas involved  controlled by number of factors • to gain access & visibility • removal of affected dentin from floor • room for restorative material • extension for prevention • mech. Interlocking retentive designs • cavosurface margins self cleaning
  18. 18. G V BLACK’S CLASSIFICATION CLASS I pit & fissure occlusal surfaces - premolars & molars lingual surfaces of maxillary
  19. 19.
  20. 20. CLASS II proximal surfaces of posterior
  21. 21.
  22. 22. CLASS III proximal surfaces of anterior teeth do not involve the incisal
  23. 23.
  24. 24. CLASS IV proximal surfaces of anterior teeth involve incisal
  25. 25.
  26. 26. CLASS V gingival third of facial or lingual
  27. 27.
  28. 28. CLASS VI  incisal edge of anterior / occlusal cusps heights of posterior teeth  Simon - later
  29. 29.
  30. 30.
  31. 31.  Concepts of Black controversial & debatable  with new adhesive restorative
  32. 32. G J MOUNT CLASSIFICATION Designed to simplify identification of
  33. 33. site size Minimum Moderate Enlarged Extensive 1 2 3 4 Pit/fissure 1 1.1 1.2 1.3 1.4 Contact area 2 2.1 2.2 2.3 2.4 Cervical 3 3.1 3.2 3.3
  34. 34. VIMAL K SIKRI CLASSIFICATION class I div 1 - pits & fissures of occlusal surfaces div 2 - B & L pits of postr & antr class II div 1- one proximal surface of postr div 2 - both proximal surfaces of postr class III div 1 - one proximal surface of antr div 2 - both proximal surfaces of
  35. 35. Class IV div 1 - cervical one-third of labial & lingual div 2 - labial & lingual line angles of all teeth  class V div 1 - labial of antr than cervical one-third div 2 - lingual of antr than pits & cervical 1/3  class VI div 1 - incisal tips div 2 - occlusal cusp
  36. 36. OPERATING SITE moist- free environment isolation protecting soft tissues margins limited to supragingival
  38. 38. INITIAL CAVITY PREPARATION  mechanical alterations of tooth extended to sound tooth structure, in all directions, while adhering to specific, limited pulpal depth  cavity walls designed to retain restoration & resist
  39. 39. INITIAL CAVITY PFREPARATION  exacavation of remaining, infected dentin  removal of old restorative materials  pulp protection  additional cavity designs - minimize fracture  finishing preparation walls  cleaning, inspecting
  40. 40. INITIAL STAGE  STEPS INVOLVED STEP:1 outline form and initial depth STEP:2 primary resistance form STEP:3 primary retention form STEP:4 convenience
  41. 41.  FINAL STAGE STEP:5 removal of remaining enamel or infected dentin STEP:6 pulp protection STEP:7 secondary resistance and retention form STEP:8 finishing external walls of cavity preparation STEP:9 cleaning inspecting varnishing and
  42. 42. INITIAL CAVITY PREPARATION extension & initial design of external walls of preparation at a specific limited depth, provide access to cavity/ defect reach sound tooth structure, resist fracture of restoration/ tooth,forces directed in long axis of tooth & retain restoration no deeper than 0.2mm into dentin - pit & fissure 0.2mm - 0.8mm - suface
  43. 43. OUTLINE FORM & INITIAL DEPTH placing cavity margins in positions will occupy in final preparations except enamel walls & margins preparing initial depth of 0.2 - 0.8mm pulpally of
  44. 44. Is the locations that the peripheries of completed tooth prepn.will occupy on tooth surfaces is the perimeter of tooth width, length & depth of
  45. 45. PRINCIPLES friable / weakened enamel removed all faults included margins placed in position- good finishing of margins of restoration extension for prevention sufficient enamel & dentin to locate the pulpal & axial walls or prepn.surfaces within 0.5mm from
  46. 46. FACTORS extent of carious lesion, defect/ faulty restorations esthetic considerations occlusal relationships adjacent tooth structure cavosurface
  47. 47. FEATURES preserving cuspal strength preserving marginal ridge strength minimizing f-l extensions enameloplasty connecting to close faults restricting
  48. 48. PIT & FISSURE CAVITIES CONTROLLED BY THREE FACTORS extent of enamel carious lesion extensions along fissures- sound smooth margin limited bur depth, pulpal depth- 1.5- 2mm & maxi depth into
  49. 49. RULES  unsupported/ weaken enamel  avoid terminating eminences  extension of primary groove- capping of cusp  all fissures  restrict pulpal depth  as conservative as possible  no: 245 bur- 2mm- f/l walls & depth
  50. 50. p & f less than 50% of pulpal floor- removed in final stage greater than 50% of pulpal floor, deepened, 0.2mm into dentin actual depth varies- depends on thickness of enamel & steepness of cuspal incline outline varies -depending on anatomic form of tooth, pit & fissures on occlusal
  51. 51.  butterfly type preparation flare & MD width of embrassures occlusion & masticatory forces caries index & oral hygiene age of patient creating more convex
  52. 52. SMOOTH SURFACE LESIONS two locations proximal surface gingival portion of facial & lingual
  53. 53. PROXIMAL SURFACE unsupported/ weakened enamel avoid terminating eminences extend margins for sufficient access restrict axial wall pulpal depth maxi- 0.2-0.8mm into dentin not remove dentin caries deeper pulpally than 0.5mm from DEJ minimum clearance 0.5mm between gingival margin & adjacent
  54. 54.  Class II preparations  placement of margins of pit & fissures  for inlays – dovetail on the occlusal surface  Class III Preparation  incisal margin of sound enamel -contact area not extended
  55. 55. GINGIVAL PORTION OF FACIAL AND LINGUAL AREA  class v  extension mesially, gingivally, distally & occlusally (incisally) limited  bur depth no deeper than 0.8- 1.25mm pulpally from original tooth surface  axial pulpal depth at occlusal wall- provides 0.5mm into
  56. 56. RESTRICTED & INCREASED EXTENSIONS RESTRICTED  proximal contours & root proximity  esthetic requirements  tooth preparations for composite restorations INCREASED  advanced age of the patient  need for additional retention & resistance form  adjust tooth
  57. 57. conventional removal of unsupported enamel width-md/bl-atleast 1.5mm pulpally & axially –atleast 1.5mm facial & lingual margins involve entire f/l groove –to avoid feather-edged marginal amalgam mortise shape –each wall & floor –flat plane, meeting each other at definite line & point angles proximal portion- box type / truncated cone isthmus- not exceed 1/3rd intercuspal distance atleast 1.5mm sweeping curves- proximal & occlusal walls
  58. 58. cavity preparation for – class I amalgam outline
  59. 59. class II cavity preparation for
  60. 60. Class III Cavity Preparation for
  61. 61. Class V Cavity Preparation for
  62. 62. modifications  Extension for prevention- not apply  conservative approach  not extend f & l more than midway between central grooves & cusp tips  enameloplasty on terminal ends of shallow fissures  proximal portion- only a unilateral inverted truncated cone on functional side of marginal angles  gingival margin located occlusal to ht of contour  isthmus- not exceed 1/4 intercuspal distance  sweeping
  63. 63. Tooth colored restorations  Extension for prevention - not apply  adhesive resto.mate.revolusionized the concept of cavity design  conserve more tooth structure  floor routinely not placed in dentin- depends on extend & depth of lesion  bevel on cavosurface margin  contact area - should be maintained  butt joint marginal configuration - for retention & bevelled the
  64. 64. Cast gold restorations Gingival to occlusal divergence of walls- 2-5 degree taper on each wall taper minimum in shallow cavities more in deeper cavities bevelling to obtain lapp joint at cavosurface margin 20- 30 degree increases marginal
  65. 65. PRIMARY RESISTANCE FORM defined as the shape & placement of the cavity walls best enables both restorations & the tooth to withstand, without fracture , masticatory forces delivered in long axis of tooth architectural form given to a tooth , which enables both restoration & remaining tooth to resist structural failure from occlusal loading
  66. 66. PRINCIPLES  utilize box shape with a flat floor  restrict extension of external walls  slight rounding of internal line angles - reduce stress  cap weak cusps & envelope / include enough weakened tooth  provide enough thickness of restorative material - prevent fracture  major principle is that restoration should rest on flat sound tooth structure, perpendicular to occlusal forces directed parallel to the long axis of
  67. 67. FEATURES relatively flat floors box shape includes weakened tooth structures preservation of cusps & marginal ridges rounded internal line angles adequative thickness of restorative materials seats on sound dentin peripheral to excavation of infected dentin reduction of cusps for
  68. 68.  Stress patterns of teeth  use floors at right angles to direction of loading- to avoid shear stress  walls parallel  box / cone / inverted truncated cone  definite line & point angles  Amalgam & cast gold - approx.1.5mm  porcelain - 2mm for inlays 1.5mm for crowns composite no criteria for resistance
  69. 69.  class I flat floor large resto.depth increased with increase in diameter  class II pulpal line angle more rounded- MOD  class III cavity extended lingually as close to incisal edge as possible  class V functn. Cusp & fossa reln.dictates stress patterns  grooves provide resistance to certain
  70. 70. PRIMARY RENTENTION FORM  shape / form of prepared cavity that resists displacement / removal of restoration from tipping/ lifting forces  defined as a form given to tooth prepn.,especially its detailed anatomy & general shape, which enables the restoration, that will accommodate, to avoid being lodged by masticatory loading  intra coronal- inside a cavity prepn,within the tooth  extra coronal on prepn.surface, replacing ext.tooth surface
  71. 71. PRINCIPLES  related to restorative materials used  retention form vary from material  higher degree of parallelism bet.opposing walls  inverted truncated cones or undercuts  dovetail  elastic deformation of
  72. 72. CONVENIENCE FORM shape/ form of cavity that provide adequate observation & accessibility ease of operation in preparing & restoring the cavity • modifications in tooth prepn. Flaring lingual / labial access • instrument modifications contra-angling bayoneting • separation wedging of
  73. 73.  Cavosuface angles • amalgam -90 degree • inlay beveled- 20-40 degree • margins located on self-cleansing areas • smooth
  74. 74. FINAL CAVITY PREPARATION Removal of any remaining enamel pit / fissure &/ or infected dentin & / old restorative material, if indicated. it is elimination of any infected carious tooth structure / faulty restoration within the tooth after initial cavity
  75. 75.  caries left in pulpal / axial floor excavated 0.75-1mm of dentin cover the pulp when affects esthetically weakened tooth- given retention secondary caries , if present periphery of old resto.mate. not
  76. 76. PULP PROTECTION pulpal injury, due to heat generated while cutting resto.mat.with good thermal conductivity chemicals from resto.mate. Galvanic currents microleakage placement of cavity liners / bases/varnish– not a step it is the step in adapting the preparation for receiving the final restorative material mechanical, chemical & thermal protection of
  78. 78.  Mechanical features retention locks grooves & coves skirts beveled enamel margins pins amalgapins slots Cavity wall conditioning features enamel, dentinal wall conditioning for bonded
  79. 79. Grooves-indicated in cast resto., prepared in wall of proximal box in DEJ depth equal to width placed at AB & AL line angles parallel or slightly divergent etching- micromechanical retention slots- prepared in dentin increase surface area more convergent walls 1-1.5mm deep box type locks-in proximal box of class II amalgam restorations 0.2-0.3mm wide & 0.5mm deep into dentin skirts-in cast restorations extensions of proximal box margins
  80. 80. Amalgam- retention enhanced parallel walls & flat pulpal floor / gingival floors occlusal convergence of walls [class II] occlusal convergence & dovetail slots in gingival floor proximal retention- AF & AL locks cast gold restorations axial retention in form of locking & friction in micro-irregularities parallelism / 2-5 degreedivergence occlusal extension- increase in area lateral retention - dovetail / pinholes & pot
  81. 81. Tooth colored restorations acid conditioning retentive cavity preparation physico-chemical retention Posts direct gold class III- undercut at point angles class IV grooves along gingivopulpal & incisal
  82. 82. FINISHING THE EXTERNAL WALLS OFCAVITY PREPARATION  further development when indicated, of a specific cavosurface design & degree of smoothness that produces maximum effectiveness of restorative material being use  to create best marginal seal bet.resto.mate.& tooth  to afford smooth marginal jn  provide maxi.strength of both tooth &
  83. 83. Features design of cavosurface margin degree of smoothness of
  84. 84. Cleaning, inspecting, varnishing &conditioning. Removing debris, chips dry the
  85. 85. G J MOUNT’S CLASSIFICATION3 SITES SITE 1: pit fissure & enamel defects on occlusal of postr or other smooth surface SITE 2: approximal enamel immede. below areas in contact with adjacent teeth SITE 3: cervical 1/3 of crown / following gingival recession, exposed
  86. 86.
  87. 87. 4 SIZES SIZE 1: minimal involvement of dentin- just beyond treatment by remineralization SIZE 2: moderate involvement of dentin SIZE 3: cavity enlarged beyond moderate SIZE 4: unnecessary to remove affected, dentin-floor but walls
  88. 88. Site 1 lesion: commences in fissure on occlusal surface of postr pits on lingual upper antr buccal surface of lower molar lingual extension of DO groove of upper molars erosion / attrition on occlusal surface of postr incisal edges of
  89. 89. size 1: small defect in one section of pit & fissure often with placement of fissure on the reminder of fissure system size 2: moderate with most fissures involved / replacement of an existing black class I restoration size 3: larger requires protection for one or more cusps in design size 4: extensive with one or more cusps already
  90. 90. 1.1  lesion on occlusal surface of postr  limited, other sections free from caries  other fissures may be deep / convoluted- subjected to later attack  unnecessary to remove affected, demineralised dentin-floor but walls clean  margins should be sound & free of microcracks & loose enamel
  91. 91.
  92. 92.
  93. 93. 1.2 G V Black I care not to extend the cavity  unnecessary to remove affected dentin- floor but walls clean  occlusal enamel should be retained, thro’ unsupported, margins are sound  no microcracks  remaining fissure
  94. 94.
  95. 95.
  96. 96. 1.3 G V Black class I  larger requires protection for one or more cusps in design  extensive undermining or breakdown of atleast one cusp with possibility of split developing at the base  care not to remove affected dentin-floor but walls clean  indirect pulp capping  all remaining cusps- need protection from occlusal
  97. 97.
  98. 98.
  99. 99.
  100. 100.
  101. 101. 1.4 G V Black class II  extensiveloss of one or more cusps  mostly
  102. 102.
  103. 103. SITE 2 proximal surface of antr / postr immediately below contact area size 1: minimal involvement of dentin- healing by remineralization size 2: extensive involvement of dentin with marginal ridge weakened / breakdown, still remaining tooth structure to support
  104. 104.  size3: postr tooth- involvment of dentin with a split at the base of a cusp need to protect one / more cuspal inclines from occlusal load antr proximal caries with loss ofsupport for incisal corner  size4: complete loss atleast one cusp from postr / incisal
  105. 105. 2.1 no equivalent in G V Black classification minimal involvement of dentin- healing by remineralization 3 different approaches- position in reln to marginal ridge / lesion in adj.tooth internal occlusal fossa / tunnel approach slot cavity
  106. 106. Internal Occlusal Fossa / Tunnel Preparation  enamel lesion atleast 2.5mm apical to crest of marginal ridge  thro’ occlusal fossa just medial to marginal ridge  create funnel shape access cavity  No specific retentive designs  marginal ridge cracked- removal of MR - cavity becomes
  107. 107.
  108. 108.
  109. 109.
  110. 110. Slot cavity  closeto MR  too weak to be maintained  access gained thro’ MR  more in antr  lesinthro’ MR - small box form cavity- not extended beyond demineralised enamel  maintain contact with
  111. 111.
  112. 112. Proximal approach if adj.tooth already in site 2- size 3/4 prepared in it with missing proximal box direct access thro’ proximal good access & visibility occlusal remains intact MR
  113. 113.
  114. 114. 2.2 G V Black classII [postr], class III [antr] if amalgam if
  115. 115.
  116. 116.
  117. 117.
  118. 118. 2.3 G V Black class III [antr], class II [postr]  antr- bevels to enhance retention  in postr identify- split at the base of a cusp  cusp that is split- modify cavity outline  support for one-half of cusp / single cusp  but all 4 cusps protected  maintainence of full ht - atleast one cusp indicate original occlusal
  119. 119.
  120. 120.
  121. 121.
  122. 122. 2.4 G V Black class IV [antr], class II [postr]  antr-loss of major section of incisal half of crown  unsupported enamel supported  margins trimmed to smooth finish  postr- retain cusps based on sound
  123. 123.
  124. 124.
  125. 125.
  126. 126.
  127. 127. Site 3  gingival 1/3 of crown or exposed root surface  on open surfaces[f/l] in reln to contours of gingi.tissue / interproximally, below contact area  caries enamel margin around full circumference- occlusal margin in enamel & gingi.margin in dentin  root surface caries  gingival
  128. 128. 3.1 G V Black class V caries found in gingi. Margin high caries risk poor oral hygiene no instrumentation for
  129. 129.
  130. 130. 3.2 G V Black class V  more
  131. 131. 3.3 G V Black class V rootsurface caries gingival
  132. 132.
  133. 133. 3.4 G V Black class V two / more caries around cervical marginof any
  134. 134. RELATIONSHIP BETWEEN BLACK’S &MOUNT’S CLASSIFICATION Site 1- size 1, 2, 3, & 4 pit fissure caries on occlusal postr/ any simple enamel defect/ smooth surface of any tooth black class I- size 1 - could not carried, no suitable resto. Material blacks begins with site 1, size 2 [1.2]
  135. 135. Site 2, size 1, 2, 3 & 4  approximal lesions [contact area]  antr / postr- immediately below contact area  black class II  no equivalent of size 1 begins with 2.2  blackclass III  no equivalent site 1 begins 2.2  black class classified as 2.4
  136. 136. Site 3, size 1, 2, 3, 4  gingival 1/3 of crown  black class V  erosion / abrasion 3.1, 3.2, 3.3,
  137. 137. CONCLUSION Better understanding of caries process improved knowledge of function of fluoride limit size of cavity retaining atleast some demineralised enamel & dentin heal thro’ remineralization retain more natural tooth
  138. 138. REFERENCES Sturdevant’s Art & Science Of Operative Dentistry; Theodore M Roberson, Harald O Heyman, Edward J Swift Jr – 4TH Edition, Mosby Publications Operative Dentistry, Modern Theory & Practice; M A Marzouk, A L Simonton, R D Gross – 1st Edition, IshiyakuEuroamerica, Inc. Publishers, Tokyo, St. Louis, All India Publishers & Distributors, Chennai Textbook of Operative Dentistry; Vimal K Sikri – 1st Edition, CBS Publishers & Distributors Principle & Practice of Operative Dentistry; Charbeneau – 2nd Edition, KM Varghese Company Fundamentals of Operative Dentistry: A Contemporary Approach; James A Summit, J William Robbins, Richard S Schwartz, Jose Dos Santor – 2nd edition, Quintessence Publishing co.Inc.
  139. 139.  Operative Dentistry; Gilmore, Lund, Bales, Vernetti – 4th Edition, B I Publications Pvt.Ltd Operative Dentistry; McGehee, True, Inskippp – 4th Edition, M C Books, Inc. Textbook of Operative Dentistry; Lloyd Baum, Ralph W Phillips, Melvin R Lund – 3rd Edition, B Saunders Company Hampson’s Textbook of Operative Dentistry; E L Hampson – 4th Edition Preservation & Restoration Of Tooth Structure, G J Mount, w R Hume 1st Edition, Mosby Publications
  140. 140.