DIAGNOSIS AND TREATMENT PLANNING PRE PROSTHETIC EVALUATION
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Pre Prosthetic Evaluation Intraoral examination Analysis of mounted study casts Bone mapping Radiographic analysis Force evaluation
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Intraoral Examination Existing
occlusion Existing occlusal plane, orientation Interarch space Existing vertical dimension of occlusion Maxillomandibular arch relations Temporomandibular joint status Existing prosthesis www.indiandentalacademy.com
Intraoral Examination Arch
form Ideal implant permucosal position Missing teeth location Missing teeth number Lip line at rest and during speech Mandibular flexure Soft tissue support www.indiandentalacademy.com
Arch form
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Diagnostic Casts Mounted diagnostic cast are invaluable for Occlusal centric relation position including premature occlusion ď ľ Edentulous ridge relations to adjacent teeth and opposing arches ď ľ Position of potential natural abutments including inclination rotation extrusion spacing parallelism and esthetic considerations ď ľ
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Position of the replacement in relation to the residual ridge
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Diagnostic Casts Direction of forces in future implant sites Present occlusal scheme including the presence of balancing or working contacts Edentulous soft tissue angulation, length, width, locations, permucosal esthetic position, muscle attachments and tuberosities
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Study Model Analysis – Edentulous Patient Pattern
of resorption - can exhibit as cross bite in posterior region and as prognathism in anterior region. Mounted study models will help ascertain vertical and sagittal relationships
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Mounted study models indicating minimum Interocclusal distance
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Mounted Study models showing large interarch space
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Prognathic relationship
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Angle class II
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Study Model Analysis – Partially Edentulous Patients
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Interarch Distances
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Evaluation Of Available Bone Evaluation
of bone quantity Evaluation of bone quality
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Available bone is evaluated by Digital Palpation Radiographs Study models Bone sounding
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Bone sounding
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OSTEOMETER
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MAINZ MEASURING GAUGE
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EVALUATION OF BONE QUANTITY
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ALVEOLAR PROCESS
FUNCTIONAL ADAPTATION
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ATWOODS CLASSES OF RESORPTION FOR MAXILLA
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ATWOODS CLASSES OF RESORPTION FOR MANDIBLE
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Classification Of Degree Of Resorption Of Edentulous Jaws By Lekholm And Zarb(1985)
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Pattern of resorption (Harle) ď ľ Maxillary
arch buccal to lingual ď ľ Mandibular arch lingual to buccal
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Available bone is studied under Height of bone Width of bone Length of bone Bone contour Crown implant ratio
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Height of bone ď ľ Vertical
extent bone available for implantation ď ľ Distance between the crest of alveolar bone to the opposing anatomic structures
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Width of bone Distance
between oral and vestibular cortical plates 1mm diameter increase = 20-30% increase in the total surface area 3mm increase in length provides more than 10% increase in surface area
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Length of bone ď ľ Minimum
distance between axis to axis between two implants is 7mm ď ľ R1+R2+2mm=distance between two implants
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Bone contour (Angulation) ď ľ Favorable
bone contour is one in which the functional and esthetic demands of the prosthesis to be borne by the implant can be fulfilled with axial loading of the prosthesis
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Divisions of Available bone quantity Division
A (abundant) Division B (barely sufficient) Division C (Compromised) Division D (Deficient)
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Division A Width
> 5mm Height >10-13mm Length >7mm C/I < 1
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Division B Width
2.5-5mm Height >10-13mm Length >12mm C/I < 1
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Options for Division B Bone Modify
the existing Div B ridge to another division by Osteoplasty Insert a narrow Div B root form implant Modify existing Div B bone into Div A by augmentation
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Disadvantages Division B Stress
at the crestal region around the implant is twice Lateral loads on the implant result in almost 3 times greater stress than Division A Fatigue fractures in the abutment are increased Crown emergence profile is less esthetic www.indiandentalacademy.com
Disadvantages Division B Conditions
around the cervical aspect of the crown for daily care is poor Angle of load must be reduced to less than 20 degrees to compensate for the small diameter Two implants are required for proper prosthetic support
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Division C Unfavorable Unfavorable Unfavorable Unfavorable
Width (C-w) Height (C-h) Angulation (C-a) C/I = 1
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Treatment options for Division C Ostoeplasty Root
form implants Subperiosteal implants Augmentation procedures Ramus frame implants Transosteal implants
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EVALUATION OF BONE QUALITY
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Bone Quality Is Evaluated By Tactile Radiographic Biochemical
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Bone density and success rates Adell
et al reported 10% greater sucesss rate in the anterior mandible compared to anterior maxilla Schnitman et al reported highest success rate of 75% in the posterior maxilla Friberg et al reported 66% of the implant failures occurred in soft bone
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CT determination of bone density D1: D2: D3: D4: D5:
> 1250 Hounsfield units 850 - 1250 Hounsfield units 350 - 850 Hounsfield units 150 - 350 Hounsfield units < 150 Hounsfield units
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Mechanostat theory of Frost ď ľ The
structure of bone is maintained by the micro strain environment ď ľ Bone reaction to different degrees of micro strains 0-50 : acute disuse window 50-1500 : adapted window 1500-3000 : mild overload Above 3000 : pathologic overload www.indiandentalacademy.com
Bone Classification Related To Implant Dentistry By Linkow (1970) Class
I Bone structure:
ideal type of bone with evenly spaced trabeculae with small cancellated spaces Class
II Bone structure:
bone has larger cancellated spaces with less uniformity of the cancellous spaces Class
III Bone structure:
large marrow spaces between trabeculae
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BONE DENSITY CLASSIFICATION BY MISCH D1
Dense cortical
D2
Porous cortical
D3
Coarse Trabecular
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D4
Fine trabecular
Bone density location D1
– 6% in anterior mandible 3% in posterior mandible D2 – most common in mandible D3 – most common in maxilla 65% in anterior maxilla 50% in posterior maxilla D4 – most common in posterior maxilla www.indiandentalacademy.com
Influence Of Bone Density On Treatment Planning Surgical
– Soft bone protocol – Selection of fixture size – Selection of the drilling sequence – Selection of the material of the implant – Auxiliary procedures Prosthetic
– Progressive loading www.indiandentalacademy.com
Evaluation of force Parafunction Position
of abutment in the arch Masticatory dynamics Nature of the opposing arch Direction of load forces Crown-Implant ratio
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