Surveying Lecture Notes (PDF)

Surveying Marketing Department Mon. Feb. 21. 2018 Dr :Mahmoud El Homossany Removable Prosthodontics Surveying Objectives of the Lecture 1- Understand Surveyor tools 2-How to use the surveyor. Surveying Chapter 11 Surveying The Component Parts of Removable Partial...

Surveying Marketing Department Mon. Feb. 21. 2018 Dr :Mahmoud El Homossany Removable Prosthodontics Surveying Objectives of the Lecture 1- Understand Surveyor tools 2-How to use the surveyor. Surveying Chapter 11 Surveying The Component Parts of Removable Partial Dentures Surveying The Component Parts of Removable Partial Dentures Denture Base Artificial Teeth Supporting Rests Connectors: Major Connectors Minor Connectors Retainers Direct retainers Indirect Retainers 3 1 2 5 4  Surveying It is the procedure of locating and delineating the contour and position of the abutment teeth and associated structures before designing a removable partial denture Undercut: An undercut is formed when the base of an object is smaller than its top Undercut Area Survey line Undercut Area Surveying Non-undercut Area f Surveying Undercuts on Teeth Is A Dig Or A Burrow Lie Below The Height Of Contour, Which Is The Most Bulbous And Convex Part Of The Tooth, Also Called Maximum Bulge or Survey Line The Survey Line is a Line Outlined On the Cast By A Surveyor Marking the Greatest Prominence Of Tooth Contour Surveying Types of undercuts Tooth Undercuts (Proximal undercuts) Soft Tissues or bony Undercuts(on lingual side of ridge)  Partially Edentulous Mouth has Many Undercuts That Result due to I-bulbous Shape Of The Crowns Of Natural Teeth Resulting In Buccal And Lingual Undercuts 2- The Inclination Of The Long Axes Of Teeth In Relation To A Vertical Line 3-The Inclination Of Soft Tissues Or Bone To A Vertical Line 4- Proliferation Of Soft Tissues Covering The Edentulous Ridge Surveying Types of undercuts 1-Desirable Undercuts 2-Undesirable Undercuts **All the Undercuts are Undesirable undercuts Except that used for Denture Retention Components Of Metallic Removable Partial Dentures Are All Rigid, With The Exception Of The Flexible Retentive Clasp Arm Located In An Undercut Area For Retaining The Restoration Against Flexible clasp arm engaging tooth undercut Dislodging Forces Path of Insertion PI Is The Direction in Which a Restoration Moves From the Point of Initial Contact With the Supporting Teeth to the Terminal Resting Position Where the Occlusal Rests Are Seated and the Denture Base Is in Contact With the Tissue Path of Removal The Direction of Movement of the Restoration From Its Resting Position to the Last Contact With the Supporting Teeth". It Is the Reverse of the Path of Insertion Selection of The Path of Insertion The Most Favorable Path of Insertion (PI) Is That Perpendicular to the Occlusal Plane Most Patients Tend to Seat Their Dentures Under Biting Force If Displacement of the Prosthesis Is Anticipated With the Least Displacing Forces If Undercuts are Present but Not Efficient at the Zero Tilt Another Path of Insertion Should Be Decided Surveying Factors Affecting Path of Insertion Interferences - Changing the path of insertion - Contouring the tooth surface - Surgery to remove interfering structures - Retentive undercuts should be equal in depth and permit the location of clasp tips in the gingival third of the tooth - Esthetics Made possible with less clasp metal and less base material displayed Guiding planes Post Is More Readily Removed by Application of Force Near Its Top Than by Applying Same Force Nearer Ground Level Clasp retention depends on amount of undercut rather than distance below height of contour Surveying Guiding planes *Flat Axial Surfaces In an Occluso-gingival Direction on The Proximal or Lingual Surfaces of Teeth. *Parallel To The Path Of Insertion Help In *Guiding The Prosthesis During Insertion and Removal Guiding planes A guide surface should extend vertically for about 3 mm, and should be kept as far from the gingival margin as possible Surveying The functions of guiding planes Guide the Prosthesis in or Out of Place Without Exerting Excessive Forces Against the Teeth The Frictional Contact of the Prosthesis Against These Parallel Surfaces, Contribute to the Retention of the Prosthesis Provide Bracing and Stability When they are Located on the Axial Lingual Surface of the Tooth Surveying Guide the Prosthesis in or Out of Place Without Exerting Excessive Forces Against the Teeth Surveying Minimize Wedging Stresses on the Abutment Teeth Minimize the Amount of Space Between the Denture and the Tooth Thus Making the Prosthesis More Hygienic Surveying Aid in Stabilizing the Prosthesis Against Horizontal Stress Surveying THE DENIAL SURVEYOR It Is a “Paralleling Instrument Used to Determine the Survey Line of Teeth, Identify and Measure Tooth Undercuts and to Determine the Relative Parallelism of the Surfaces of Teeth and Other Areas on the Cast” Surveying THE DENTAL SURVEYOR It is a “Paralleling instrument enables a person to draw “ a contour map” on the teeth and tissue areas of a cast”  Surveying It is the procedure of locating and delineating the contour and position of the abutment teeth and associated structures before designing a removable partial denture Surveying Dental Surveyor Ney Surveyor Jelenko Surveyor Surveying The Location of the Undercut Area Can Be Changed by Changing the Tilting Surveying The location of the undercut area can be changed by tilting the cast anteriorly or lateral Surveying Parts of the Dental Surveyor A- The Base B- Vertical Upright Column C- Cross Arm with Spindle Housing D- The Vertical Spindle With Tool Holder E- Screw To Lock The Spindle F- Tool Holder H- The Surveyor Table M- Ball Retaining Ring N- Tool Rack O- Storage Compartment Surveying Tools 1- Analyzing Rods 2- Carbon Marker 3- Undercut Gauge 4- Wax Trimmer Surveying Analyzing Rod Surveying Surveying Carbon Marker Surveying Undercut Gauges Of an inch ??? of mm. Undercut Gauge Surveying Undercut Gauge Surveying Wax Trimmer Surveying OBJECTIVES OF SURVEYING Permit an Accurate Charting of the Required Mouth Preparations Determine the Most Acceptable Path of Placement and Removal Determine the Relative Parallelism of Teeth Surfaces That Act As Guiding Planes Determine Soft, Bony or Tooth Undercuts and Areas of Interferences Identify and Measure Tooth Undercuts Delineate Height of Contour Trimming Blockout Material Parallel to the Path of Placement Recording the Cast Position Surveying Surveying Ceramic Veneer Crowns Surveying Machining Cast Restorations Surveying Surveying the Master Cast To select the most suitable path of placement by following mouth preparations that satisfy the requirements of guiding planes, retention, noninterference, and esthetics. Surveying Surveying the Master Cast To permit measurement of retentive areas and to identify the location of clasp terminals in proportion to the flexibility of the clasp arm being used; To locate undesirable undercut Surveying Surveying the Master Cast To trim blockout material parallel to the path of placement before duplication Surveying Surveying Factors that Determine Path of Placement and Removal Guiding Planes Retentive Areas Interference Esthetics Surveying PRINCIPLES OF SURVEYING  The Prosthesis Can Goes Smoothly Into Place Without Interference After Analyzing the Proximal Tooth Surfaces and Making the Necessary Alteratio Surveying Recontouring the tooth surface Surveying The Location of the Undercut Area Can Be Changed by Changing the Tilting Surveying The location of the undercut area can be changed by tilting the cast anteriorly or lateral A Cast in a Tilted Relationship Represents a Path of Placement Toward the Side of the Cast That Is Tilted Upward Cast at zero tilt. Creation of undercut by tilting cast Selection of The Path of Insertion The Most Favorable Path of Insertion (PI) Is That Perpendicular to the Occlusal Plane Most Patients Tend to Seat Their Dentures Under Biting Force If Undercuts are Present but Not Efficient at the Zero Tilt If Displacement of the Prosthesis Is Anticipated With the Least Displacing Forces Another Path of Insertion Should Be Decided Selection of the Path of Insertion Tilting the Cast to Create Suitable Undercuts Equalize Undercuts on both Sides of the Arch Place the Clasp Tips in a Better Esthetic Po. Undercut Areas Should Be Present at Both Zero Tilt and the New Tilt Gross Inclination of the Cast to Create Apparent Undercuts Should Be Avoided  PROCEDURES of SURVEYING 1- Placement of the Cast 2- Altering the Cast Position Anteroposteriorly To Provide Parallel Proximal Surfaces That May Act As Guiding Planes 3- Tilt the Cast Laterally Until Equal Retentive Areas Exist on the Principal Abutments 4- Eliminate Areas of Interference by Reshaping Tooth Surfaces 5- Permits a More Esthetic Placement of Clasp Arms Than the Othe After Selection of the Proper Path of Insertion, the Cast Is Secured in Place * Drawing of the Survey Line * Location of the clasp terminals * Blocking the Undesirable Undercuts * Tripoding or Scoring Surveying Tripoding the Cast Scoring the Cast Surveying It has been estimated that an error of 0.2 mm can be anticipated when a cast with three reference points Tripoding Or Scoring are Performed While the Master Cast is Still Mounted on the Survey Table Without Changing the Tilt to Preserve the Established Cast Tilt Surveying Surveying Step-By-Step Procedures in Surveying A Diagnostic Cast I-Guiding Planes Surveying The end result of selecting a suitable anteroposterior tilt should be to provide the greatest combined areas of parallel proximal surfaces that may act as guiding planes. Other axial surfaces of abutment teeth may also be used as guiding planes. Surveying II-Retentive Areas Alter the cast position by tilting it laterally until similar retentive areas exist on the principal abutment teeth Surveying III-Interference A mandibular cast is being surveyed, check the lingual surfaces that will be crossed by a lingual bar major connector during placement and removal. Bony prominences and lingually inclined premolar teeth are the most common causes of interference to a lingual bar connector. Surveying III-Interference Other areas of possible interference to be evaluated are those surfaces of abutment teeth that will support or be crossed by minor connectors and clasp arms. Although interference to vertical minor connectors may be blocked out, doing so may cause discomfort to the patient’s tongue and may create objectionable spaces, which could result in the trapping of food. Surveying III-Interference When the retentive area is located objectionably high on the abutment tooth or the undercut is too severe, interference may also exist on tooth surfaces that support retentive clasps. Such areas of extreme or high convexity must be considered as areas of interference and should be reduced accordingly. These areas are likewise indicated on the diagnostic cast for reduction during mouth preparations Surveying IV-Esthetics if a choice between two paths of insertion of equal merit permits a more esthetic placement of clasp arms by one path than the other, that path should be given preference. When anterior replacements are involved, the choice of path is limited to a more vertical one for reasons previously stated. Surveying Modifications of master cast All guiding-plane areas must be parallel to the path of placement, and all other areas that will be contacted by rigid parts of the denture framework must be made free of the undercut by parallel blockout. Relief must also be provided for the gingival crevice and gingival margin. Black regions designate parallel blockout at proximal guide-plane surfaces and relief along the palatal marginal gingiva. Surveying Surveying Relief and blockout of the master cast before duplication. All undercuts involved in the denture design have been blocked out parallel to the path of placement, except the retentive tips of the retainer clasps. Residual ridges have been provided 20-gauge relief for denture base material. Surveying Surveying Surveying Thank You