Inlays and Onlays - Inlays are used to fill cavities in molars or premolars. - They are an alternative to direct restorations. - Inlays cover the pits and fissures of a tooth. - They are mainly used for the chewing surface between the cusps. - Inlays can be made from gold, porcelain, or ceramic materials. - Inlays have a fine line of contact, minimizing recurrent decay. - Inlays have no limitations in material choice. - Inlays are superior in resistance to occlusal forces and protection against recurrent decay. - Long-term studies show no significantly lower failure rates for ceramic or composite inlays compared to direct fillings. - Inlays are indirect restorations without cuspal coverage. - They are used when amalgam or composite restorations are inadequate. - Inlays are fabricated outside of the mouth. - They can be made from gold or porcelain. - Inlays can be made in a dental laboratory or using CAD/CAM dentistry. - Inlays/onlays are indicated when teeth are weakened and extensively restored. - Inlays are used for repeated breach in the integrity of a direct filling. - Inlays are used when placement of direct restoration is challenging. - Onlays are used to protect weakened tooth structure without additional removal of tooth tissue. - Onlays can be used if there is minimal contour of remaining coronal tooth tissue. - Poor oral hygiene is a contraindication for providing inlays and onlays. - Plaque and active caries should be managed before providing indirect restorations. - Caries risk should be reduced to prevent recurrent caries around the restoration. - Subsequent caries can be caused by plaque retentive features or poor bonding. - Contraindications may result in failure of the restoration. - Parafunctional habits and heavy occlusal forces are contraindications for inlays and onlays. - Evidence shows greater failure of onlays and inlays in molars than premolars. - Porcelain fracture is the most common cause of failure. - Avoiding heavy occlusal forces can ensure longevity. - Cuspal coverage onlays should use porcelain instead of composite. - Indirect restorations are contraindicated in patients under 16. - Large pulp chamber and wide dentinal tubules increase stress on the pulp. - Risk of nerve supply damage during cavity preparation. - Unfavorable margins due to continued eruption and skeletal development. - Waiting until full cooperation is advantageous. - Patients need to cope with dental impressions for indirect restorations. - Digital impression systems can help patients who can't withstand conventional impressions. - Digital impressions provide highly accurate models and eliminate patient discomfort. - However, these systems are not widely available in dental practices. - Extensive caries or tooth surface loss may require full coverage extra coronal restorations. - Direct restorations like composite may be beneficial for small restorations. - Inlays require elimination of undercuts, so direct restorations preserve tooth structure and avoid laboratory costs. - Tooth preparation aims to preserve more tooth tissue compared to crown preparation. - Preparation of opposing cavity walls should avoid undercuts for optimum retention. - All-ceramic restorations allow slightly over-tapered cavity shapes. - Gold restorations require parallel walls for retention. - Two appointments required for preparation and cementation, with a provisional restoration in the meantime. - Indirect restorative technique involves taking an impression and using CAD-CAM technology. - CAD-CAM allows for one-visit provision of indirect restorations. - Lost wax technique using Type 1 or Type 2 inlay wax can be used for cast metal/ceramic restorations. - Inlay wax is chosen for its brittleness to identify and remove undercuts. - Lost wax technique involves embedding the wax pattern into investment material for casting.

Casting Methods - Metal can be melted using gas and compressed air, gas and oxygen, or electric arc. - Casting methods include steam pressure or a centrifugal system. - Porosity can occur due to uncompensated alloy contraction and absorption of mold gases. - Possible casting faults include subsurface nodules, ridges, fins, roughness, and foreign bodies. - Gold can be used to produce inlays and onlays, with oxides removed by ultrasonic bath.

Slip Casting Technique - Applicable only to sintered alumina core porcelain. - Sub-structure made of alumina powder and modeling fluid is built on a special die. - Sintering the die with the sub-structure absorbs the fluid and tightens the alumina powder. - Lanthanum aluminosilicate glass powder is painted on the outer surface of the sub-structure. - Zirconium oxide can be applied for further strengthening.

Direct Restorative Technique - No impression of tooth preparation required. - Tooth preparation is coated with separating material like glycerin. - Composite restoration is built directly on the preparation, taking the shape of the cavity. - Restoration is light-cured in the tooth and then removed for further light-curing. - Only applicable when composite is used as the restorative material.

Materials and Benefits - Ceramic inlays produced via indirect restorative techniques have similar longevity. - Study by Rippe et al. supports this finding. - Longevity of ceramic inlays is comparable regardless of the production method. - No specific statistics or numbers provided. - Indirect restorative techniques contribute to the longevity of ceramic inlays. - Gold has high strength and ductility, making it ideal for withstanding masticatory forces. - Ceramic offers more aesthetic restoration color and high wear resistance. - Unreinforced ceramic has reduced strength and higher fracture risk. - Composite provides great aesthetics and can be easily repaired or modified. - Metal-ceramic inlays have lower fracture resistance compared to all-ceramic inlays. - Inlays and onlays improve the sturdiness and wear of teeth. - Super curing enhances the durability of inlays. - Close to parallel walls and