FUNDAMENTALS OF TOOTH PREPARATION.pptx

fundamentals of tooth preparation

1. FUNDAMENTALS OF CAVITY PREPARATION Presented By, AISHWARYA KHARE Guided By, Dr. Anurag Jain Dr .Sonal Bansal Dr. SaurabhMankeliya

2. CONTENT INTRODUCTION CAVITY PREPARATION DEFINITION HISTORY OBJECTIVES OF CAVITY PREPARATION FACTORS AFFECTING CAVITY PREPARATION CLASSIFICATION STAGES OF CAVITY PREPARATION

3. Introduction Dr. G.V. Black Chicago, Illinois 1836-1915 "The Grand Old Man of Dentistry" The basic principles governing the design of cavity and steps in their preparation was first suggested by American Dentist and teacher Dr.G.V.Black in the first decade of last century.

4. DEFINITION OF CAVITY PREPARATION The mechanical alteration of a defective, injured, or diseased tooth to receive a restorative material that re-establishes a healthy state for the tooth including esthetic corrections where indicated, along with normal form and function . - by sturdevant

5. Cavity preparation is the mechanical removal of caries and shaping the remaining tooth tissue in such a way so that after restoration it can withstand masticatory forces and will be able to prevent subsequent caries . - by DR. vimal k sikri

6. Types of cavity preparation CONVENTIONAL :- Tooth preparation that relates to amalgam, gold and ceramic might be considered conventional preparation that require specific wall form, depth and marginal form. MODIFIED: Tooth preparation for bonded direct restorations as composite or glass ionomer has less need for specific depth , wall and marginal form and is considered to be modified preparation .

7. OBECTIVES OF TOOTH PREPARATION Remove all defects and provide necessary protection to the pulp. Extend the restoration as conservatively as possible . Tooth prep such that under mastication both the tooth and restoration will not fracture or displace. Allow the functional and esthetic placement of a restorative material.

8. FACTORS AFFECTING TOOTH PREPARATION GENERAL FACTORS Diagnosis Prevention Interception Preservation Restoration

9. PATIENTS FACTORS Economic status Esthetic concern Age Choice of material

10. Classification G.V. Black Classification Modification of G.V.Black Classification Graham J Mount V.K. Sikri

11. G.V.Black Classification First Classification Universally Accepted Based on type of treatment and area involved Controlled by no. of factors To gain access & visibility. Removal of affected dentin from floor. Room for restorative material. Extension for prevention. Retentive designs. Cavosurface margins self cleaning areas.

12. G.J.Mount classification -design to simplify identification of lesions According to site lesion 1.Pits &fissure 2.Contact area 3.Cervical According to size of lesion 1.Minimum 2.Moderate 3.Enlarged 4.Extensive Sikri classification - classify same as G.V. Black and then gave division in each class

13. TOOTH PREPARATION TERMINOLOGY : Simple tooth preparation -Only one tooth surface is involved. Compound tooth preparation – Only two tooth surface is involved. Complex tooth preparation – Involves three or more surfaces.

14. Terminology in Cavity Preparation Definition – Cavity-Cavity is defined as a defect in enamel or dentin resulting from pathologic process of dental caries(breach in the continuity of the surface integrity of tooth). The term cavity was used to describe a carious lesion in a tooth that has progressed to the point that part of tooth structure has been destroyed.

15. Tooth preparation walls INTERNAL WALL -An internal wall is prepared surface that does not extend to external tooth surface. AXIAL WALL – An axial wall is an internal wall parallel with the long axis of the tooth. PULPAL WALL- A pulpal wall is an internal wall that is perpendicular to the long axis tooth and occlusal of pulp.

16. External wall – An external wall is prepared surface that extend to the external tooth surface Floor / seat-A floor is a prepared wall that is reasonably flat and perpendicular to the occlusal forces that are directed occlusogingivally . Enamel wall –Enamel wall is that portion of a prepared external wall consisting of enamel. Dentinal wall- The dentinal wall is that portion of a prepared external wall consisting of dentin ,in which mechanical features can be located.

17. CAVITY PREPARATION ANGLES : Line angle : It is the junction of two planar surfaces of different orientation along a line. internal line angle and an external line angle. Internal line angle : Is a line angle whose apex points into the tooth e.g. FP. External line angle : Is a line angle whose apex points away from the tooth e.g. AP . Point angles : A point angle is junction of three planar surfaces of different orientation .

18. Cavo s urface angle : The cavosurface angle is the angle of the tooth structure formed by the junction of a prepared cavity wall and the external surface of the tooth . Line angles & point angles Cavo-surface angle

19. Classification of cavity Class I Class II Class III Class IV Class V Class VI — G. V. Black

20. CLASS I CAVITY PREPARATION All Pits & fissures preparation are termed as class I. these include preparation on: 1) Occlusal surface of premolars & molars. 2) Occlusal 2/3rd of facial & lingual surface of molars. 3) Lingual surface of maxillary incisors .

21. DESIGNS OF CLASS I CAVITY PEPARATION

22. UPPER PREMOLAR: these preparation are dumb bell shaped with their ends somewhat triangular. LOWER PREMOLARS:- If they are confined to pit only , the preparation are circular, resembling snake eye. But if they involve entire occlusal surface then the preparation will resemble design of upper premolar, except that mesial end of the dumb-bell in lower first premolar will be more linear.

23. LOWER 1 ST MOLAR:- Elongated mesio -distally with three lateral extension, two buccal and one lingual, corresponding the primary grooves LOWER 2 ND AND 3 RD MOLAR:- Elongated shape with 2 lateral projections, usually opposite one another, corresponding the primary groove.

24. In tricuspid lower premolars, the preparation will assume Y- shaped with two of the arms of the Y ending in a triangular cavity.

25. UPPER 1 ST MOLAR:- If the cavity involves all of the occlusal surface , the preparation will be elongated, mesio -distally , with lateral projections not opposite one another. if the oblique ridge is not crossed , the mesial cavity preparation will assume a “kidney” shaped and distal cavity preparation will assume a “heart “ shape. UPPER 3 RD MOLAR:- upper 3 rd molar with 3 cusp , the cavity will assume T- and Y- shape.

26. These above mentioned shape are generalizations and no cavity preparation will assume these shapes exactly . They can be modified according to anatomical and cariogenic consideration. LOCATION OF THE MARGIN: Adjacent to ridges. Adjacent to cusps.

27. INTERNAL ANATOMY: Pulpal floor:- The portion of preparation is usually located in dentin 0.2-0.5mm from the DEJ. Should be flat planed and at a right angle to the long axis of the tooth.

28. Only exception is lower 1 st premolar where lingual cusp is small and buccal cusp is very pronounced with a very large pulp horn. Creating a flat pulpal floor will jeopardize both the minute lingual cusp and buccal pulp horn So in this case floor is prepared in a flat plane, parallel to the imaginary line joining the tip of buccal and lingual cusp.

29. CLASS 1,DESIGN 2

30. It is used for teeth with intact cusp i.e., cusp not undermined by backward decay. GENERAL SHAPE : Shapes of this preparation is similar to design 1, e xcept there are more deviation from the generalized shapes previously mentioned. LOCATION OF MARGIN: Similar as class 1 however in design to margins are closer to cusp tip and crest of the ridge than design 1 margins.

31. INTERNAL ANATOMY The pulpal floor will have probably different levels in design 2. One is established by the penetration of the caries cones and will have a concave shape . Another one , the main level, which should be flat, is approximately 0.2-0.5mm from the DEJ. Mesio - distal and buccolingual cross-section is similar to that of design 1.

32. CLASS 1 DESIGN 3

33. Preparation will have same features as mentioned in the above designs except the wall of the preparation could be more convergent and irregular according to the anatomy of the invagination.

34. CLASS 1, DESIGN 4

35. INDICATION:- Caries lesions at the facial or lingual pits are connected to the occlusal surface or lesion through the fissure , enamel decay or backward decay. Decay undermine the facial and lingual marginal ridges, or thins them so they cannot be self-resistant. Caries cones, facially or lingually ,are confined to the concavity of their corresponding grooves.

36. 3.LOCATION OF MARGINS:-Margins of occlusal part of cavity preparation will be located at same site as described for design 1 Mesial and distal margins of facial and lingual parts of the preparation will be located on the corresponding surface. In these portion of preparation the must be seperated from each other by atleast 1.5mm.

37. CLASS 1, DESIGN 5

38. CLASS 1, DESIGN 6

39. INDICATION Portion of entire cusp are undermined by backward decay, or badly thinned by direct decay, necessitating partial or total replacement of the cusp by a restorative material. The cariogenic situation leaves a cusp or part of a cusp with a length to width ratio of 3:1 or more in a functional cusp ,or 4:1 in a non functional cusp and there is no interruption in continuity of surrounding walls .

40. 3. The cariogenic situation leaves a cusp or part of a cusp with a length to width ratio of 2 or more on the functional cusp and more on the non functional cusp and the continuity of the surrounding walls is interrupted at one part or another. 4. The marginal ridge adjacent to an occlusal preparation is crossed by a fissure to the facial or lingual embrasure.

41. 5.A foundation for a future cast restoration is needed. 6.A class 1 occlusal lesion is continuous with a class VI lesion on the cusp tip or their ridge crests.

42. CLASS1 DESIGN 7

43. INDICATIONS They are class 1 lesion with extensive carious involvement. Due to substantial extent the resulting deficiency of surrounding walls, the placement of internal boxes in the floor of preparation is impossible due to anatomical restrictions. Pins and post are indicated. Pins and post retained restorations.

44. CLASS1, DESIGN 8

45. LOCATION In molars and premolars. This design is used on the occlusal and sometimes on the occlusal and/or facial-lingual surfaces . It also may be used on the lingual surfaces on anterior teeth. INDICATION:-Designed specially for endodontically treated teeth. Confined to occlusal and lingual or buccal surface of these teeth.

46. CLASS II CAVITY PREPARATION preparation involving the proximal surface of posterior teeth are termed class II.

47. MODIFICATION OF CLASS 2 CAVITY PREPARATION CLASS 2, DESIGN 1: INVOLVEMENT: This design is indicated for: A moderate to large size proximal lesion with the occlusal surface of the affected tooth involved in a lesion of similar size. A proximal lesion undermining an adjacent marginal ridge(s) or not accessible through any other means but involvement of the occlusal surface .

48. c. The caries cones occlusally and or proximally necessitates the cavity width to exceed one-fourth the intercuspal distance. d. A class II in stress concentration area(i.e., proximal lesion adjacent to a functional triangular fossa). e. Patient with high caries index and plaque indices. f. An oral environment where local cariogenic conditions contraindicates a modern design.

49. N

50. CLASS 2 DESIGN 4

51. CLASS 2 DESIGN 6

52. CLASS III CAVITY PREPARATION Pr eparation involving the proximal surface of anterior teeth that do not include the incisal angle are termed as class III.

53. CLASS IV CAVITY PREPARATION Preparation involving the proximal surfaces of anterior teeth that include the incisal edge are termed class IV .

54. CLASS V CAVITY PREPARATION P reparation on the gingival third of the facial or lingual surface of all teeth are termed as class V.

55. CL ASS VI CAVITY PREPARATION Preparation on the incisal edges of anterior teeth or the occlusal cusp tip of posterior teeth are termed as class VI.

56. Stages of Cavity Preparation INITIAL STEPS OF CAVITY PREPARATION

57. FINAL STEPS OF PREPARATION

58. Outline Form and Initial Depth Definition: placing the cavity margins in the positions they will occupy in the final preparation except for the finishing enamel walls and margins; preparing an initial depth of 0.2~0. 5 mm pulpally of the dentinoenamel junction and 0.8mm pulpally to the normal root surface .

59. Principles : 1.All unsupported friable and weakened enamel should be removed. 2.All fault should be included 3.All margin should be placed in a position to allow finishing of margins of restoration.

60. PROCEDURE

61. Features: 1.Preserving cuspal strength. 2.Preserving marginal ridge strength . 3.Minimizing facio-lingual extension. 4. Connectiong two close (0.5mm apart )defect or tooth preparation. 6.Restricting depth of penetration into dentin

62. 1.Preserving cuspal strength -avoiding termination of the margin on extreme eminence, such as cusp height -if extension of primary groove includes half / > of cusp incline, then CUSP CAPPING consider.

63. 2. Preserving marginal ridge strength Remaining Marginal ridge should be greater than 1.6 mm for premolar & 2mm for molar If Remaining Marginal ridge will be less than 1.6 mm there there may be the chances of fracture due to undermining the ridge.

64. Direction of mesial & distal walls When >1.6 mm thickness width is remained at mesial /distal marginal ridge , then mesial / distal wall should be parallel . When less than/= 1.6 mm thickness width is remained at mesial /distal marginal ridge , then mesial / distal wall should be divergen t.

65. 3. Minimizing facio –lingual Extension - Minimizing facio –lingual Extension ,which prevents the weakening of cusp. For conservative class I CAVITY facio-lingual width should be 1 to 1.5 mm

66. 4. Depth of preparation Restricting depth of penetration into dentin for pits and fissure-0.2 for smooth surface-0.2 to 0.8 Because, 1.To avoid the seating of the restoration on the very sensitive DEJ. 2.To give the bulk of restoration. 3.To take advantages of dentin elasticity during insertion and function.

67. 5. Enameloplasty This is the procedure of reshaping the enamel surface by making it rounded / Saucered ,the area becomes cleansable and finishable. It is indicated when remaining fissure is not greater than 1/3 rd of enamel thickness.

68. Outline form for class I The outline form varies from one tooth to another . Premolars- Upper premolars have “ Dumb- bell “ shape with their ends triangular. In lower premolar –are confined to pit only but if they involve entire occlusal surface ,then they resemble like upper premolar. In tricuspid lower premolar it will assume Y-shape

69. Class I upper premolar Class I lower premolar

70. Class I & II Outline form for MOLARS Preparation in lower molars have an elongated shape mesio-distally with three lateral extensions. In upper molars if cavity involves all the occlusal surfaces ,the preparation elongated mesio-distally . If the oblique ridge is not involved the mesial preparation will assume kidney shape & distal will appear as heart shape . In class II the shape of proximal box is Inverted Truncated Cone.

71. Mandibular Maxillary ClassⅠoutline form Occlusal view Proximalview Class II outline form

72. Position of Gingival floor In class II cavity preparation ,gingival margin should be extended apically of proximal contact to provide a minimum of 0.5 mm clearence between the gingival margin and djacent tooth.

73. Position of Embrassure wall Isthmus – By G.V.Black - Advocate that class II cavity preparation with isthmus width equal to 1/3 rd of intercuspal distance . By Vale & Brooner - It should be 1/4 th of intercuspal distance.

74. The axio-pulpal line angle should be beveled to reduce the concentration of stresses and provide grater bulk of material in the isthmus area, which is liable to fracture .

75. Final location for the facial and lingual Walls of proximal box relative to the contact area REVERSE CURVE – When viewed from occlusal outline form of class II cavity particularly in max . teeth the proximal contact lies towards the buccal surface whereas the groove line occurs in the central portion of th occlusal table. This disparity necessitates occlusal outline with a REVERSE CURVE . Advantages 1.It preserve the triangular ridge of cusp 2.Facilitates formation of 90°angle between proximal wall & the tangent of proximal surface.

76. Initial cavity preparation stage Step 1 Outline form and initial depth Step 2 Primary resistance form Step 3 Primary retention form Step 4 Convenience form

77. 2. Primary Resistance Form Definition: It is defined as that shape and placement of the cavity walls that best enable both the restoration and the tooth to withstand, without fracture, when masticatory forces delivered principally in the long axis of the tooth .

78. Primary Resistance Form Principles: To utilize the box shape with a relatively flat floor to resist occlusal loading by virtue of being at right angles to mastication force; To restrict the extension of the external walls (keep as small as possible) to allow strong cusp and ridge areas to remain with sufficient dentin support;

79. Primary Resistance Form Principles: To have a slight rounding of internal line angles to reduce stress concentration in tooth structure; To provide enough thickness of restorative material to prevent its fracture under load.

80. Primary Resistance Form Feature: Box shape Relatively flat floors Inclusion of weakened tooth structure Preservation of cusps and marginal ridges Rounded internal line angles Adequate thickness of restorative materials Reduction of cusps for capping if indicated

81. Flat pulpal floor prevents rocking of the restoration which produce wedging forces

82. Pulpal wall is flat in all cases except in lower 1st premolar ,where the lingual cusp is very small & buccal cusp is pronounced with very large pulp horn. So in this case we have to make flat pulpal floor which is parallel to imaginary line joining the tips of the and lingual cusp. Exception

83. Rounding of line angles prevents stress concentration & provide resistance form & Shows strongrst enamel margin by full length of enamel rods

84. Facio-lingual width should be not more than ¼ th the intercuspal distance . As minimum tooth structure is removed, it increases the resistance of tooth. ¼ th intercuspal distance

85. The type of restorative material also dictates resistance form need Silver amalgam needs thickness -1.5 mm Cast metal needs thickness -1to2mm Porcelain needs thickness - 2 mm

86. Initial cavity preparation stage Step 1 Outline form and initial depth Step 2 Primary resistance form Step 3 Primary retention form Step 4 Convenience form

87. 3. Primary Retention Form Definition: primary retention form is the shape or form of conventional preparation that resists displacement or removal of the restoration from tipping or lifting forces. In many respects retention and resistance form are accomplished in the same cutting procedure.

88. Principal means of retention Frictional retention - 1.Greater surface area (length, width, depth)produces greater frictional component. 2.Parallel walls / convergent wall provide greater frictional retention 3. Proximity –bringing the restorative material closer to tooth structure during insertion provide greater frictional retention component. 4.Elastic deformation of dentin –during condensation within dentin proportional limit can add more gripping action.

89. 4. Inverted truncated cones - In class II cavity preparation , proximal surface have inverted truncated cones shape -It prevents the occlusal displacement of restoration in class II Cavity.

90. 6. Dovetail In Class II Cavity - Dovetail provide retention in class II cavity . -It prevents lateral displacement of restoration in class II cavity . In Class I Cavity - In class I ,it is given for the purposeful modification in outline usually for ‘ EXTENSION FOR PREVENTION ’

91. Primary Retention Form Principles: For Amalgam restoration: -developing external cavity walls that converge occlusally. - Adhesive system provide retention by micromechanically bonding amalgam to tooth structure.

92. Primary Retention Form Principles: Composite restoration: a mechanical bond between the material and conditioned, prepared tooth structure.

93. Initial cavity preparation stage Step 1 Outline form and initial depth Step 2 Primary resistance form Step 3 Primary retention form Step 4 Convenience form

94. 4 . Convenience Form Conception: The shape or form of the cavity that provides for adequate observation, accessibility, and ease of operation in preparing and restoring the cavity.

95. Convenience Form Principles: Allow access for caries removal Allow access for restoration placement Allow access to margins for finishing, evaluation and cleaning

96. Convenience Form

97. -In class II cast restoration divergence of vertical wall -extending proximal preparation beyond proximal contact -In class III cavity convenience form mainly through lingual side. - In class I & V , divergence of wall of cavity in INLAY

98. Final cavity preparation stage Step 5 Removal of any remaining infected dentin or old restoration, if indicated Step 6 Pulp protection Step 7 Secondary resistance & retention form Step 8 Procedure for finishing external walls Step 9 Final procedures

99. 6. Removal of any remaining infected dentin or old restoration, if indicated Definition: The elimination of any infected carious tooth structure or faulty restorative material left in the tooth after initial cavity preparation.

100. Removal of dentinal caries using round burs and spoon excavators

101. Removal of dentin depends on the two condition whether it is affected or infected ? Affected dentin -Does not contain micro-organisms -can be remineralise by restorative mean. -it is accepted to allow affected dentin to remain in prepared tooth. Infected dentin -It contain micro-organisms -can not be remineralise by restorative mean. -it should be removed during cavity preparation.

102. -Soft decay can be best removed using spoon excavator by flaking up the caries -Hard decay, heavily discolored should removed using very low speed bur. -care should have to take during removal as pulp may infected by forcing micro- organisms into dentinal tubules through excessive pressure.

103. Final cavity preparation stage Step 5 Removal of any remaining infected dentin if indicated Step 6 Pulp protection Step 7 Secondary resistance & retention form Step 8 Procedure for finishing external walls Step 9 Final procedures

104. 6. Pulp protection - Using liners or bases - to protect the pulp or - to aid pulpal recovery or both. LINERS-liners are volitile /aquous suspension /dispersion of zinc oxide or calcium hydroxide that can be applied to tooth surface in relatively thin film & are used to effect a particular pulpal response . BASES- Are those cements used in thicker dimensions beneath permanent restoration to provide for mechanical, chemical ,thermal protection of the pulp

105. -Liners are primarily used to provide a barrier to protect dentin from residual reactants. -Bases are used to provide thermal protection for the pulp and to supplement mechanical support for the restoration by distributing local stresses from restoration across the underlying dentin surface. If remaining dentin overlying the pulp is 2mm then no need of liners But if it is less than 2mm ,pulp protection is mandatory .

106. Schematic view of needs for pulpal protection below metallic restoration

107. Schematic examples of liners & bases for amalgam restoration For shallow tooth preparation For moderate tooth preparation For very deep tooth preparation

108. Final cavity preparation stage Step 5 Removal of any remaining infected dentin if indicated Step 6 Pulp protection Step 7 Secondary resistance & retention form Step 8 Procedure for finishing external walls Step 9 Final procedures

109. 7. Secondary resistance and retention forms Most compound and complex cavity preparations require additional resistance and retention form. The exception being those preparations that are very conservative.

110. Secondary resistance and retention forms Mechanical forms Cavity wall conditioning form

111. Mechanical form: Retention locks, grooves, and coves Groove extensions Skirts Beveled Enamel Margins Pins, Slots, Steps, Amalgampins

112. Proximal Grooves for cast restoration Retention locks for amalgam

113. Incisal retention coves Incisal & Gingival retention groove

114. Groove extensions & skirts When lingual wall absent or inadequate in proximal preparation, then retention form can be improved by facial skirt extension.

115. Pins slots steps & amalgampins Beveled Enamel margins -The bevels for cast metal may improve retention form -Primarily to afford a better junctional relationship -Beveled margins increases the surface area of etchable enamel Dentin slots Amalgampins

116. Cavity wall conditioning form Placement of etchant , Primer , Adhesive on prepared wall -in addition to mechanical alteration to tooth structure certain bonding agents also provide some extent of retention & resistance form -such treatment require in bonded restoration like porcelain , composite , or amalgam materials

117. Micromechanical retention of bonding system to dental enamel

118. Final cavity preparation stage Step 5 Removal of any remaining infected dentin if indicated Step 6 Pulp protection Step 7 Secondary resistance & retention form Step 8 Finishing external walls Step 9 Final procedures

119. 8. Finishing the external walls Definition: is the further development of a specific cavosurface design and degree of smoothness that produces the maximum effectiveness of the restorative material being used.

120. Finishing the external walls Objectives: To create the best marginal seal possible between the restorative material and tooth structure; To afford a smooth marginal junction; To provide maximum strength of both the tooth and the restorative material at and near the margin.

121. The strongest enamel margin is that margin which is composed of full-length enamel rods that are supported on the cavity side by shorter enamel rods, all of which extend to sound dentin.

122. Finishing the external walls The design of the cavosurface angle The degree of smoothness of the wall

123. The design of the cavosurface angle: depending on the material amalgam: 90°( Cavosurface margin 90 °-Butt joint) Help to minimize the marginal deterioration of restoration by locating the margins away from the enamel eminence where occlusal forces may be concentrated. composite: beveling 30°~ 40° Is indicated primarily in larger restoration because the potential for retention increased by increasing the surface area of enamel available for etch.

124. Occlusal cavosurface margin Proximal cavosurface margin

125. Vertical section of Class II Tooth preparation -a slight bevel is given to remove unsupported enamel rods

126. Gingival Bevel placed with an instrument Gingival marginal trimmer

127. Final cavity preparation stage Step 5 Removal of any remaining infected dentin if indicated Step 6 Pulp protection Step 7 Secondary resistance & retention form Step 8 Procedure for finishing external walls Step 9 Final procedures

128. Final procedures cleaning inspecting Sealing

129. A . Water, air, or combinations of both B . Dry cotton pellets are very efficient and safer way to dry preparation . C. Using cavity cleaner (vey low conc. Of citric acid ,ascorbic or acetic acid),dilute sol. Of hydrogen peroxide. D. Scraping preparation walls with sharp hand instrument. E. Irrigate the cavity with saline before drying. F. Inspecting the cavity for any remaining debris G. Sealing the cavity H. Composite requires etching ,priming & bonding before insertion of restoration .

130. Cavity preparation seen after final procedure

131. References 1.Sturdevants- Art and Science Of Operative Dentistry 2.Marzouk – Modern Theory and Practice 3.G.V. Black –Work on operative dentistry 3.Vimal Sikri- Textbook of Operative Dentistry

132. Thanks