CAD-CAM Dental Restorations PDF

## CAD-CAM ### Comparison between traditional methods and CAD-CAM for fabrication of indirect dental restorations | Traditional method | CAD-CAM systems | | :--------------------------------------- | :-------------------------------...

## CAD-CAM ### Comparison between traditional methods and CAD-CAM for fabrication of indirect dental restorations | Traditional method | CAD-CAM systems | | :--------------------------------------- | :------------------------------------------------------- | | Time-consuming | Less time-consuming | | Complex processing | Simple processing | | Higher chance for processing errors | Less chance for processing errors | | Less accurate | More accurate | | Highly dependent on technician's skills | Dependent on software | | | **It is a chain process** | | | 1. **Scanning phase (data acquisition)** | | | * **Clinic (intraoral scanning)** | | | * **Lab (model or impression scanning)** | | | * **CEREC Systems (Dentsply Sirona)** | | | 2. **Designing Phase** | | | * **Clinic** | | | * **Lab** | ### Scanning phase (data acquisition) - **Direct scanning of teeth intraorally** - Technique-sensitive - Superimposed adjacent teeth/gingiva/salivary interference - Difficult registration of margins. - **Extruoral scanning** - Scanning of dental models - **Types of scanners** - **Optical scanner** - **Types (Laser scanner/Light scanner)** - **By optical camera** - Use white light or laser beam - Based on "triangulation procedure" - Light source and receptor (camera) present at a specific angle in relationship to each other - **By touch probe (highly accurate technique)** - Model is mechanically scanned line-by-line by a ruby ball - **Mechanical scanner** - Disadvantages - 10 touch technique ### Milling phase | | | | ----------------- | --------------- | | **3-AXIS milling devices** | **XYZ** | | **4-AXIS milling devices** | **XYZ, O** | | **5-AXIS milling devices** | **XYZ, AB, O** | - **Number of movement axes** - **3 linear axes (XYZ)** - **3 linear axes XY, Z** - **2 rotatory axes (AB)** - **1 rotatory axis (O)** - **Advantages** - Less cost compared to other types - **Types of milling** - **Wet milling** - Use of water/oil sprays to avoid overheating of the material during milling - For materials liable to cracking or chipping due to heat generation - Cobalt-chrom - No cooling system - **Dry milling** - For soft materials or materials not liable to cracking or chipping - Zirconia - PMMA - Advantages - Minimize shrinkage and sintering distortion - Lower cost - No need to dry ZrO2 prior to sintering (no moisture absorption) - Disadvantages - Higher shrinkage during sintering - Development of microcracks - Surface defects ### Designing phase - Using specified software CAD: - Produce Standard Tessellation Language (STL file) - Examples: - EXO CAD - Mesh Mixer - Blender - Mesh Lab ### Materials available for CAD-CAM | | Materials supplied as | | :-------- | :-------------------------- | | Ceramics | Blanks | | | Partially sintered (Continuum) | | | Completely sintered | | Polymers | Monochromate | | Metals | Polychromate | | Waxes | | ### Uses of CAD-CAM | | | | :--------------- | :----------------------------------------- | | **Fixed Restorations (Metal Ceramic - PEEK)** | | | 1. Inlay/Onlay/Overlay | | | 2. Crowns/Bridges/Veneers | | | 3. Inlay Bridges | | | **Removable Prosthesis (PMMA/PEEKR)** | | | 1. PMMA dentures / Metallic Framwork | | | 2. Surgical guide | (For accurate implant placement) | - **Advantages** - Reduce chair time and number of visits - Digital archiving - Higher precision/accuracy/retention - Superior mechanical & Physical properties - Reduce the use of traditional impressions - Cross-infection control in Clinic/Lab - **Disadvantages** - High cost - Material waste CAD-CAM - Wear of milling feels - Chairside CAD-CAM technique is time-consuming for the dentist - **To overcome this disadvantage, use additive manufacturing (3D printing)/waste can be recycled.**