- Indirect restorative materials vary in composition, physical and mechanical properties, processing methods and clinical indications, all of which must be considered to determine the most suitable material for a specific case.
- The development of newer, stronger materials offers professionals the opportunity to combine aesthetics with durability.
- Significant advances in digital fabrication techniques are changing the way care is delivered.
In 2003, the ADA Council on Scientific Affairs classified dental restorative materials into two broad groups based on whether they needed lab work (sometimes in the office) or an additional visit to complete the restoration. Direct restorations can usually be completed in one visit, while indirect restorations are done in the laboratory based on impressions of the patient's tooth and typically require multiple visits to shape, fabricate, and finally seat the restoration.1Although technological advances (particularly CAD-CAM) have blurred the distinction between direct and indirect materials since 2003, this oral health topic generally follows the 2003 classification (see ourOral health topic in direct restorative dental materials). A variety of indirect restorative materials are available, offering a range of strengths and durability, as well as aesthetic and cost considerations. Indirect restorations can be conventionally cemented or, depending on material properties and the clinical setting, require adhesive fixation to the tooth. A range of water-based and resin-based cements are available, further expanding the range of material combinations for the final restoration.1, 2
Indirect restorations generally consist of five categories of materials: precious metal alloys, base metal alloys, ceramics, composite resins, and metal-ceramics.1Metals have historically been common in indirect restorations because of their durability and strength, but the desire for tooth-colored materials has led to an increase in ceramic options. However, ceramics are prone to cracking and chipping, but bonded to metal they provide durability and strength. Technological advances, particularly in the use of CAD/CAM systems, have expanded the possibilities of all-ceramic restorations and have rapidly gained popularity due to their ever-increasing appearance and durability.3Metal use continues to decline as the Internet raises concerns about toxicity.3See Biocompatibility and Exposure Concerns section below for more information.
Table 1: General properties of indirect dental materials
Table 1. General properties of classes of indirect dental materials.
test table below
|Highly Noble, Noble Leagues||base metal alloys||full pottery||Resin-based compound||metalocerâmico|
|Indications or primary use||Inlays, Onlays, Crown, |
|crowns, fixed bridges, |
|Inlays, Onlays, Crown, |
|Inlays, Onlays, |
tentatively long term
|Fixed crowns and bridges|
|contraindications||front teeth||nickel hypersensitivity||high stress areas; |
|too much stress||Depending on |
ceramics and metal
|Benefits||bending strength, |
|hardness, durability, |
|material dependent, |
|Lack of wear on opposite arch, |
repairable, easy to use
|material dependent, |
|Disadvantages||cost, aesthetics ||metallic sensibilities, foundry, |
|High breakage potential ||wear, discoloration ||material dependent, |
|biocompatibility||well tolerated ||Some metal sensibilities||well tolerated ||well tolerated||Depende do metal |
|aesthetics||Arm ||Arm ||excellent/tooth color ||Very good ||depends on the materials |
Indirect restorative materials: metallic alloys
In 2003, the ADA Council on Scientific Affairs classified alloys according to their precious metal content:
Table 2. Classification of ADA dental alloys (ADA Council on Scientific Affairs, 2003).This content is currently archived and is for informational purposes only.
high precision alloys
≥ 60% (gold and platinum group)
titanium and titanium alloys
Titan ≥ 85%
≥ 25% (gold and platinum group)
Mainly base leagues
< 25% (gold and platinum group)
precious metal alloys
Noble alloys, particularly gold, have been used the longest in the history of dentistry and are often cited as the standard by which other dental materials are judged.1, 4-6Normally, the metals considered noble for dental applications are gold and platinum group metals (platinum, palladium, iridium, rhodium, osmium and ruthenium).7-9Noble metals are comparatively thermodynamically stable and therefore inert in humid environments, making them ideal for use as dental materials (although titanium and CrCo alloys offer a kinetic barrier to oxidation; see below).9, 10As dental materials, precious metals typically need to be mixed with additional elements to produce alloys with increased strength that are useful as indirect restorations.8Because gold is so soft and malleable, it must be tempered with copper, silver, platinum, or some other hard, durable metal.4, 8For example, adding 10 wt% copper to gold increases the tensile strength from 104 MPa to 395 MPa.8
ANSI/ADA Specification #134*/ISO 22674:201611classifies metallic material requirements for fixed and removable prostheses and appliances:8, 12, 13
Table 3. ANSI/ADA Standard No. 134/ISO 22674:2016 Requirements for Dental Casting Alloys.
Small restorations of resilient fixed teeth.
Low-stress fixed single-unit restorations:
Fixed single restorations:
Fixed multi-unit prostheses, e.g. bridges
Devices with thin sections that are exposed to very high forces:
High stiffness (greater than 150 GPa) and strength:
Noble alloys can be used for a variety of restorative purposes, typically from tooth-supported type 1 inlays (126 MPa) to lower ductility type 2 inlays (146 – 221 MPa), but can also be used for high strength type 3 . High-strength crowns and onlays (207 MPa soft / 276 MPa hard) and Type 4 heavy-duty bridges and partial denture frameworks (350 / 607 MPa).12The use of lower grade precious metal alloys (≥ 25%) is more limited to Type 3 (248-309 MPa soft / 310-648 MPa hard) and Type 4 (420-460 MPa soft / 530-700 MPa) applications hard).12
base metal alloys
In the 1980s, the rise in the price of gold led to the development and increased use of base metals.1, 12However, as mentioned above, unlike noble metal alloys which derive their corrosion resistance from their relative inertness in the oral environment, base metals used for dental applications may attribute their corrosion resistance to the presence of passive oxide layers. . These oxide layers, such as titanium oxide and chromium oxide, reduce the rate of corrosion to extremely low levels under typical oral conditions. The hardness of base alloys compared to gold makes adjustments difficult,1and base metals are more likely to have biocompatibility issues (see Biocompatibility section below).1, 14
Nickel-chromium and cobalt-chromium are the most common base alloys, although various base elements can be added, including aluminum, molybdenum, manganese, and silicon to increase strength, castability, and/or corrosion resistance.9, 12, 15Nickel-chromium alloys are commonly used for crowns and fixed partial dentures.4, 12More elastic cobalt-chromium alloys have yield strengths of about 240 MPa to 650 MPa,12, 15and are mainly used for removable partial dentures.12
titanium and titanium alloys
Titanium is popular in the medical and dental fields because of its low strength-to-weight ratio, corrosion resistance, and biocompatibility.8, 12, 16Unlike the thermodynamic stability of precious metals, titanium's reaction with the environment is limited by a tough oxide layer (titanium oxide) that controls the rate of corrosion, reducing it to extremely low rates in typical oral conditions.10Titanium can be used as a restorative material in its unalloyed form, commercially pure titanium, with yield strength ranging from 240 MPa to 550 MPa, depending on the grade.8, 12Titanium can be alloyed with aluminum and niobium (Ti-6Al-7Nb, 795 MPa) or vanadium (Ti-6AL-4V, 860 MPa) for added strength,12, 16although there are some biocompatibility concerns regarding the possible release of toxic vanadium.12Titanium and its alloys can be used for crowns, implants and partial frameworks.8, 12, 16
*ANSI/ADA Standard No. 134 supersedes ANSI/ADA Standard No. 5 for Dental Casting Alloys and ANSI/ADA Standard No. 14 for Dental Base Metal Casting Alloys.
Indirect restorative materials: ceramics and composites
Metal alloys have proven to be effective, durable and long-lasting, but the desire for aesthetic and tooth-colored restorations has made the use of ceramic materials more popular in modern dentistry. The fragile nature of pottery - "can crack without warning if excessively bent"12–
and the possibility of its hardness causing wear damage to opposing teeth raised concerns about longevity.1, 17, 18But the advantages of ceramics for dental restorations - esthetics, chemical inertness and wear resistance - have made ceramics a rapidly evolving area of restorative dental science.12
The ISO and ANSI/ADA standards for dental ceramics classify both ceramics according to their intended clinical use (or function). They use 5 grades based on meeting recommended clinical indications with minimum mechanical strength and chemical solubility requirements (Table 4).19
Table 4: ANSI/ADA Standard No. 69 (ISO 6872)19
Minimum resistance to bending
(a) Monolithic ceramics for inlays, onlays, veneers,
(a) Monolithic ceramic for single crowns adhesively cemented on the front and
(a) Monolithic ceramic for non-adhesively cemented single crowns,
(b) Framework ceramics for anterior or posterior one-piece prostheses
(a) Monolithic ceramic for three-unit prostheses with molar restoration;
Substructure for multi-unit fixed prostheses
Silicate glasses, porcelains, glass-ceramics and polycrystalline ceramics are all types of ceramics used in dentistry.12Feldspar porcelains were the first all-ceramic restorative materials, but despite their high translucency they are inherently brittle.12, 20-22with low bending strength (50 – 100 MPa). Beginning in the 1950s, feldspar porcelain was fused to metal to reinforce the restoration (see metal-ceramic section below).6The discovery of leucite in feldspar porcelain in the 1960s allowed the strengthening of porcelain dispersion, as well as the modification of its coefficient of thermal expansion.23The 1980s saw the start of the development of high-strength glass-ceramics that could be made from pressed ingots rather than powder-liquid mixtures. Around the same time, improvements in computer-aided design software, the emergence and proliferation of milling machines and wax 3D printers, and improvements in dental zirconia and glass-ceramics spurred the digitization of laboratory procedures for dental ceramics.12Several classes of ceramic materials are currently widely used for CAD/CAM processing: zirconia, glass-ceramic, and resin-ceramic composites.
zirconium oxide ceramic
Zirconia ceramic has a naturally white appearance and has high flexural strength (≥900 MPa) and fracture toughness (~9-13 MPa m1/2).12, 21, 22Zirconia is metastable for three possible atomic arrangements, monoclinic, tetragonal and cubic phase. Yttria is added to zirconia to stabilize the tetragonal phase of zirconia at room temperature and therefore make it more resistant.12Tetragonal zirconia can be subjected to a process known as transformation hardening, which allows the material to stop the progression of an incipient crack.12Increasing the yttria content further stabilizes the more translucent cubic phase, and zirconia restorative materials are generally characterized by the amount of incorporated yttria.24Zirconia has been shown to be highly biocompatible (used as an orthopedic biomaterial since the 1970s),12and provides resistance to bacterial adhesion.21
zirconia frameEFully anatomical zirconium oxideare viable alternatives to PFM and all-metal restorations with high flexural strength (1000-1400 MPa). The zirconia framework, usually composed of tetragonal zirconia polycrystals (3Y-TZP) stabilized with 3 mol% yttria, is commonly used in anterior and posterior multi-unit bridges and is coated with feldspar porcelain or glass-ceramic for a natural appearance tooth due to its opacity.25Full-contour zirconia, which is also commonly made from 3Y-TZP, has similar flexural strength and fracture toughness, but better translucency due to its lower alumina content, which allows it to be used as a monolithic restoration.22Polished zirconia surfaces have been shown to be more resistant to wear on the opposing tooth structure than the feldspar porcelain used in metal-ceramic crowns.22
A recent study (2020) reported lower fracture toughness than previously published figures, averaging 5.64 MPa m1/2for 3Y-TZP when using focused ion beam (FIB) samples instead of saw blade notched samples.26
A high-translucency zirconia stabilized with 5 mol% yttria (5Y-ZP) is more translucent than previous generations of zirconia due to the increased content of optically isotropic cubic phase and is less prone to degradation at low temperatures.22However, it is more brittle and has lower bending strength (500-700 MPa).27A recent review (2018)27found no significant difference between 5Y-ZP and other ceramic materials tested in terms of enamel wear and bond strength to adhesive cement.27
A 2021 ADA ACE Panel Survey found that among respondents (N= 277), the most common uses of zirconia for fixed restorations were posterior crowns and bridges (98% and 78%, respectively), followed by anterior crowns and bridges (61% and 57%, respectively), and as custom implant abutments ( 51%).28Zirconia was used much less frequently for onlays, veneers and inlays (12%, 12% and 6% respectively).28Please see ourACE Panel Report on Zirconia Restorationsfor more information.
glass based systems
Glass ceramics based on leucitehave a translucency almost similar to feldspar porcelain, but may have a higher strength (above 100 MPa) due to the increased leucite content.12However, the use of leucite-based ceramics is limited to veneers and aesthetic bonded crowns in the anterior region.ceramic-lithium disilicate(LDS) with higher flexural strength (250 – 400 MPa) and availability in low, medium and high translucency molds allow for a wide range of anterior indications.12, 22There are some problems with wear compared to zirconia,12, 27and with roughness in milled LDS, but it is more resistant than other glass-based ceramics and more translucent than any zirconia.12Lithium silicate (LS) and zirconia-reinforced lithium silicate (ZRS) are available alternatives with similar properties and indications; ZRS contains 10% dissolved zirconium oxide.29
resin matrix composites
Resin matrix materials such as indirect restorations have the advantage of being easy to manipulate.12, 30, 31Resin matrix composites are capable of a greater degree of loading and polymerization than direct composites, and because they cure outside the mouth, polymerization shrinkage does not occur as with direct resin matrix composite restorations.12CAD/CAM resin matrix composite blocks for indirect restorations may be more biocompatible than direct composites, often made from alternative, non-toxic resins, and more resistant to degradation and leakage (see Biocompatibility Issues section below) .30They usually consist of a matrix of urethane dimethacrylate (UDMA), triethylene glycol dimethacrylate (TEGMDA) and/or bisphenol-A-glycidyl methacrylate (Bis-GMA) with silica, silica-based glasses, glass ceramics, zirconia and/or zirconia - silica-ceramic fillers .30, 31Resin-matrix composites in the form of composite blocks present greater flexibility to masticatory loads, with less abrasiveness compared to opposing teeth, but lower flexural strength (100 - 200 MPa) and fracture toughness (0.8 - 1.2 MPa1/2) than typical CAD/CAM blocks. Due to their lower resistance, they are mainly indicated as an alternative to inlays, onlays and single crowns.12
Indirect restorative materials: metal-ceramic
"Porcelain fused to metal (PFM)", also known as metal-ceramic prosthesis,12it was the most common type of indirect restoration before the advent of CAD/CAM-based ceramics.6, 21PFMs combine the strength and durability of an alloy core with the natural tooth aesthetic appearance of a porcelain exterior.
Requirements for alloys used in PFM are addressed in ANSI/ADA No. 134/ISO, similar to other metallic materials suitable for the fabrication of dental restorations and appliances. With these norms13, 32The fabrication of coupon sections requires that metallic materials supposedly recommended for use with ceramic veneers have their coupons tested after applying a simulated ceramic firing schedule. The standards further require that linear thermal expansion be measured for materials said to be recommended for use with a ceramic veneer and, from these measurements, the coefficient of linear thermal expansion (CTE), which is a measure of the thermal expansion of a material when is heated will be calculated and reported.13, 32Ceramic veneer material performance and metal-ceramic bonding are covered in Part 1 of ISO 9693 (ANSI/ADA No. 38).33
Therefore, the alloys used in PFM include the same types of noble, noble, titanium and base metals described in Table 2, which also meet the requirements specified in ANSI/ADA No. 134/ISO 22674 for alloys intended for use with Ceramic veneer is recommended. For a good metal-ceramic restoration system, the CTE. For a good metal-ceramic restorative system, the CTE of the alloy should be in the same range or slightly higher than8, 34coating ceramics.12, 34
Palladium's low CTE compared to other precious metals makes it highly compatible with a wide variety of ceramics and is a common element in precious metal alloys used in PFM systems.12Gold-platinum-palladium (Au-Pt-Pd) alloys were the first alloys used to melt porcelain. other combinations of gold, palladium, and silver, sometimes with gallium or copper, complete the elements added to high noble and noble alloys used for PFMs.8, 12, 35Indium, tin and iron can also be added to high and noble alloys to improve bonding, while rhenium improves ruthenium's granularity and smelting.8
Although titanium has known biocompatibility in dentures as a PFM alloy, results have been mixed, with casting issues and some evidence of poor bond strength.8, 12Surface treatments of titanium alloy prior to bonding to porcelain have been shown to improve performance.8, 12, 35Likewise, base metal alloys are more sensitive to engineering due to increased hardness and stiffness compared to other alloys, although they are considered to be more fusible.12, 35
Survival and longevity of indirect restorative materials
Restorations made of metal and metal alloys, especially gold, have long been considered the most durable and durable.1, 36-39and are reported to have an average lifespan of 18-20 years,37with some reports going back over 40 years.40A 2017 follow-up study of 25 later gold crowns showed no failure after 50 years.41In a 2010 review of the longevity of indirect and direct posterior restorations, cast gold inlays and onlays had the lowest annual failure rate at 1.4%.36Secondary caries and failure of retention are among the most common reasons for failure of gold restorations.5, 42However, many factors are responsible for the ultimate failure of a restoration, not just the materials used, and several studies have found a variety of failure and survival rates for a variety of materials and applications (see Table 5).
Table 5. Annual failure rates and survival rates from recent studies.
Annual failure rate (median)
Cast gold alloy (inlays and onlays)
96,1 (10) - 73,5 (30)5, 43
Gold alloy crowns (rear)
97 (10)5, 46- 85 (25)46
94,247- 91 (10)48
CAD/CAM systems(average, single tooth)
Lithium Disilicate or Reinforced Leucite
Ceramics infiltrated with glass
40.347– 94,6 (5)45
91.245– 98,550(5), 67,2 (10)50
Resin composites (crowns)
Resin composites (Inlays)
100 (3) - 50 (10)51, 52
Porcelain has a natural tendency to fracture, and crown fracture has been described as the most common complication in all-ceramic materials.17A fracture rate of 1.6% per year has been reported in all materials, with central fractures accounting for 1.5% but veneers accounting for only 0.6% per year.18Lateral teeth have a significantly higher fracture rate than front teeth, especially molars.18On the other hand, a 2013 study showed that only 0.2% of PFM crowns resulted in failure due to fracture in an average of 13 years in service.46while another study showed that 2.6% of GFPs ended within 5 years.45Most failures in MAPs are the result of oral pathologies.46
Fixed all-ceramic (FDP) prostheses were compared with metal-ceramic prostheses in a two-part series of systematic reviews in 2015.45, 53, 54All-ceramic single crowns proved to be significantly less reliable than metal-ceramic ones with a 5-year survival rate of 90.7% and 94.7%, respectively.45Similarly, in multi-unit FDPs, reinforced glass-ceramic FDPs had a significantly lower 5-year survival rate, 85.9%, than metal-ceramic, 94.4%.53, 54Furthermore, a 2016 report by the Canadian Agency for Medicines and Health Technologies compared the effectiveness of all-ceramic versus metal-ceramic crowns and found similar results: a survival rate of 84-100% for all-ceramic and 92-96% for PFMs versus 8 years.55Other studies have reported a 97% 10-year survival rate for metal-ceramic crowns,5, 56with most failures being due to masticatory force and trauma to the anterior region.56
Veneer chipping is a common complication with both PFMs and all-ceramic crowns; A 2015 systematic review reports a 5-year rate of 2.6% for GFPs.45In general, among all-ceramic restorations, zirconia and alumina-based restorations have a higher frequency of veneer chipping.12, 45although the 2013 report found that 3.3% of lithium disilicate crowns chipped during a 9-year follow-up study.49
A 2016 systematic review of feldspar porcelain and glass-ceramic veneers found an overall survival rate of 89% at an average of 9 years.48Porcelain veneers had an 87% cumulative survival rate at an average of 8 years, while glass-ceramic veneers had a 94% cumulative survival rate at 7 years.48Chipping was the most commonly reported complication at a rate of 4%; while debonding, discoloration and endodontics had a complication rate of 2%.48Usually feldspar porcelain41and densely sintered alumina17reported higher failure rates in anterior teeth.
A 2012 prospective study of 82 anterior and 22 posterior lithium disilicate glass-ceramic crowns in 41 patients revealed a survival rate of 97.4% at 5 years and 94.8% at 8 years (restoration replacement is considered a failure).49Similarly, a 2017 critical review found a 97.6% survival rate for lithium disilicate crowns.17Again, the most common complications with all-ceramic crowns were fractures and chipping; There was no significant difference in failure rate between anteriorly and posteriorly placed lithium disilicate crowns.17
Zirconia is still evolving as a restorative material, and while the potential for high strength and translucency is promising, evidence for long-term viability is limited. Short-term survival rates (up to 5 years) are in the range of traditional ceramic and metal-ceramic restorations.45, 53, 54, 57-59A 2014 systematic review found a 5-year survival rate of 95.9% for supported teeth and 97.1% for implant-supported zirconia crowns, while a 2018 retrospective cohort study reported 5-year survival rates for implant-supported zirconia crowns. up to 98.5%, but that dropped after 10 years to only 39.3% in the region of the lateral teeth (molars).50As with porcelain, the most common complications of zirconia-based restorations are chipping and fractures; a 5-year fracture rate of 1.09% for monolithic zirconia restorations (all types),60and a fracture rate of 3.31% for all types of layered zirconia61have been reported (see Table 6). A 2021 ADA ACE Panel report found that among responding dentists (N= 277), 52% indicated that restoration dislodgement was the most common concern with zirconia restorations, while wear on opposing teeth (31%) and restoration fracture (23%) were also common concerns.28Please see ourACE Panel Report on Zirconia Restorationsfor more information.
Table 6. Fracture rates in zirconia-based restorations.
Type of zirconia-based restoration
Fracture rate (5 years, %)60, 61
monolithic single crown
Monolithic multi-drive FDP
single tiered crown
Multi-layer, multi-drive FDP
Biocompatibility and exposure concerns
ANSI/ADA Standard #41 and ISO 7405 provide guidelines and methods for evaluating the biocompatibility of dental materials. The US Food and Drug Administration (FDA) regulates and monitors trade in non-exempt medical and dental devices under a classification system based on risk level.12, 62The 20-part ISO 10993 standard specifies the biological evaluation of medical devices and can also be used to ensure that there are no toxic, carcinogenic or other significant local or systemic health effects arising from contact with dental materials.12, 63
The incidence of an adverse reaction to a dental material is reported to be as low as 0.14% in the general population,12, 64and 0.33% in a population of prosthetic patients.12Base metals are responsible for most reactions to indirect dentures.12The release of metal ions as a result of corrosion from metallic materials used in restorative dentistry has been linked to causing irritation or allergic reactions.65, 66The components of an alloy can leak out of the material during corrosion, which is influenced by the temperature and pH of the oral cavity.66, 67The most common symptoms of hypersensitivity or an allergic reaction to a dental material are rash (allergic contact dermatitis), cheilitis, oral lichenoid lesions, inflammation (stomatitis) and burning, tingling and itching of the oral mucosa or face.12, 66, 68
For information on the biocompatibility of resin materials, visit ourOral health topics page on direct restorative materials, and Bisphenol A Concerns on this page.
Precious metals are very resistant to corrosion but can cause adverse reactions when bonded with base metals.12For example, nickel is known to be a common contact allergen.1and has the highest rate of side effects.66Between 10% and 20% of the general population is sensitive to nickel, although its oral manifestation is less common and less severe.1, 8, 15, 66Because nickel can be a naturally occurring impurity in an alloy's components, ANSI/ADA and ISO standards require manufacturers wishing to claim that their alloy is “nickel-free” to display the following marking on their packaging: “nickel-free; contains less than 0.1% nickel”.13, 32
Cobalt and chromium are also known to cause allergic reactions in about 8% of the general population;66other metals such as copper, tin, mercury and zinc, even gold, palladium and titanium have reported allergic reactions, but the prevalence is unclear.12, 66, 68
Cross-reactivity can be responsible for a number of side effects, and palladium is often associated with allergic reactions when mixed with nickel, chromium, and/or cobalt.12, 66Beryllium, a known carcinogen, is sometimes added to base metal alloys to improve castability, but it can cause inflammation, allergic reactions or other adverse effects, especially when mixed with nickel and chromium.12ISO 22674 and ANSI/ADA Standard #134 designate beryllium as a hazardous element, and to meet the requirements of the standard, metallic dental materials must not contain more than 0.2% (by weight) of beryllium.13, 32Cobalt has also been linked to a potentially fatal heart condition called cobalt cardiomyopathy.69Allergic reactions to highly biocompatible titanium have been reported,66, 70, 71but it may be the result of cross-reactivity, particularly when alloyed with beryllium or other base metals.68
Dental ceramics are highly biocompatible and exhibit low rates of surface degradation, although extremely acidic environments can increase the release of silicon ions.12Zirconia has not been associated with sensitivity or allergic reactions, and it is generally believed that minor adverse reactions reported with ceramics result from surface irritation.12
Improper safety precautions and handling techniques can lead to occupational exposure to dental materials in the form of inhaling particles released during laboratory processing of metals and ceramics. Chronic inhalation of beryllium vapor has been linked to pneumoconiosis, along with other illnesses.12, 72, 73although ANSI/ADA Standard 134 and ISO 22674 require less than 0.02% (by weight) beryllium in dental alloys.11, 13A 2018 CDC report emphasized the importance of respiratory protection when working with these materials.74According to the Occupational Safety and Health Administration (29 CFR 1910.134) Employers must provide adequate respiratory protection if workers are likely to be exposed to contaminated air in the workplace.75
ADA guidelines on dental materials
Scientific evaluation of dental restorative materials(Trad.2003:387)
Determined that although the safety and efficacy of dental restorative materials have been extensively researched, the Association will continue to actively promote such research in accordance with its research agenda to ensure that the profession and the public have the most up-to-date and scientifically valid information on which decisions to make To attend dental treatments that require restorative materials, even more so
Decided that the Association would use its existing communication tools to educate opinion leaders and policy makers about the scientific methods used to evaluate the safety and effectiveness of dental restorative materials, and be even more
Resolved that the Association will continue to promptly inform the public and the profession of any new scientific information that significantly contributes to the current understanding of dental restorative materials.
American Dental Association
Adopted in 2003; Classified 2017
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- Elsaka SE, Elnaghy AM. Mechanical properties of lithium silicate glass-ceramics reinforced with zirconium oxide. Dent Mater 2016;32(7):908-14.
- Mainjot AK, Dupont NM, Oudkerk JC, Dewael TY, Sadoun MJ. From Crafts to Blocks CAD-CAM: State of the Art of Indirect Composites. J Dent Res 2016;95(5):487-95.
- Gracis S, Thompson VP, Ferencz JL, Silva NR, Bonfante EA. A new grading system for all-ceramic and ceramic restorative materials. Int J Prosthodont 2015;28(3):227-35.
- International organization of normalization. ISO 22674:2016: Dentistry - Metallic materials for fixed and removable restorations and appliances: International Organization for Standardization; 2016
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- Goldstein GR. The longevity of direct and indirect posterior restorations is uncertain and may be affected by several factors related to the dentist, the patient and the material. J Evid Based Dent Practice 2010;10(1):30-1.
- Manhart J, Chen H, Hamm G, Hickel R Buonocore Memorial Lecture. Review of clinical survival of direct and indirect restorations in the posterior permanent dentition. Opera Dent 2004;29(5):481-508.
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- Studer SP, Wettstein F, Lehner C, Zullo TG, Scharer P. Long-term survival estimates of molten gold inlays and onlays with their failure analysis. J Oral Rehabilitation 2000;27(6):461-72.
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- Walton TR. Up to 25-year survival and clinical performance of 2,340 high-gold metal-ceramic single crowns. Int J Prosthodont 2013;26(2):151-60.
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Scientific Information, Evidence Synthesis and Translation Research Division, ADA Science & Research Institute, LLC.
What materials are used in indirect restorations? ›
Indirect restorations generally consist of five categories of materials: noble metal alloys, base metal alloys, ceramics, resin-based composites, and metal-ceramics.What are examples of indirect restorations? ›
Indirect restorations include crowns, bridges, dental implants, inlays, onlays, and veneers. Another main difference between direct and indirect restorations is that indirect restorations require more modifications to your natural tooth structure.What are the materials for direct restorations? ›
Since 2003, the ADA Council on Scientific Affairs has classified materials for direct restorations into four categories: amalgam, resin-based composites, glass ionomer, and resin-modified glass ionomer.What are the steps for indirect restoration? ›
The clinical steps were: root desobturation; acid etching with phosphoric acid; use of 2.5% sodium hypochlorite solution; post's cementation using self-adhesive cement with previous application of silano; confection of temporary material; laboratorial step to produce the restoration; cementation of restoration.What are direct and indirect restorative materials? ›
Direct restorations can be placed during a single appointment to restore areas of minor damage or decay, while indirect restorations can be used to treat more extensive cases. The best way to know which type of restoration is best for you is to have your local dentist examine your teeth and make a recommendation.Which types of wax is used for indirect restorations? ›
Inlay wax—A specialized dental wax that can be applied to dies to form direct or indirect patterns for the lost-wax technique, which is used for the casting of metals or hot pressing of ceramics.Is amalgam direct or indirect? ›
Direct restorative dental materials include amalgam, resin-based composite, glass ionomer, resin modified glass ionomer and acrylic.What type of glass ionomer cement is used for cementing indirect restorations? ›
Glass ionomer cements are supplied in special formulations according to their use. Type I is a luting cement used for the cementation of indirect restorations. Type II is designed for restoring areas of erosion in Class V. Type III is used for liners and bases.What defines an indirect restoration? ›
1 Direct restorations are repairs made inside of the mouth (fillings), while indirect restorations are fashioned outside of the mouth and then affixed to either the tooth or the supporting tooth structure in a separate procedure (examples include veneers and crowns).What are two most commonly used materials for restorative fillings? ›
The types of restorative materials selected by the general dentist are: (1) amalgam, which is the clinical name for silver fillings (this restorative material, first introduced in 1826, was perfected by G.V. Black in 1895); (2) composite resins, which are becoming the most widely accepted material of choice by dentists ...
Are glass ionomer cements used for direct restorations? ›
Different types of direct restorative materials are used in daily dental practice. The most common, next to amalgam, are resin composites, and glass-ionomer cements (GICs).What is IRM the restorative material of choice for? ›
IRM Intermediate Restorative material is designed for intermediate restorations intended to remain in place for up to one year. The eugenol content in the polymer-reinforced zinc oxide-eugenol composition gives the material sedative like qualities on hypersensitive tooth pulp and is a good thermal insulator as well.What is another name for an indirect restoration? ›
Restorations can be fillings, inlays, onlays or dental crowns. An indirect restoration is done outside the mouth. Usually a dentist takes an impression of the tooth, sends it to the lab technician who makes the indirect restoration (inlay, onlay or crown).Is a denture an indirect restoration? ›
Indirect dental restorations
Common procedures in this category include crowns, veneers, bridges, dentures, implants, inlays and onlays.
Contraindications of Indirect esthetic restoration of posterior teeth: 1-Poor oral hygiene. 2-Excessive tooth wear. 3- Impossible moisture isolation.What is the significance of indirect restorative materials to operative dentistry? ›
Indirect materials are used to fabricate restorations in the dental laboratory that then are placed in or on the teeth; placement of indirect materials generally requires two or more visits to complete the restoration.What is the ideal restorative material? ›
An ideal restorative material should be biocompatible, resistant to fracture, demonstrate longevity, be affordable and easy to manipulate, even in a resourcestrained environment 4 .What are the 2 main types of wax? ›
There are two different types: soft wax and hard wax. Although both do a good job of removing hair from the follicle, hard wax is better for smaller, more sensitive areas like your bikini line. Soft wax, on the other hand, is a better option for larger areas like your legs.What are the three types of inlay wax? ›
- Paraffin wax.
- Ceresin wax.
Indirect technique refers to fabrication of the restoration outside the oral cavity in the laboratory following which it is luted to the tooth with resin cement. There are two types of indirect composite restorations, first and second generation of indirect composite restorations.
What are indirect fillings? ›
Indirect tooth restorations involve the dentist producing customised tooth replacements, such as Crowns, Bridges, Veneers, Inlays and Onlays. An indirect filling will generally require more than one visit to the dentist as they will need to be formed in a laboratory.What are direct and indirect fillings? ›
Direct fillings are usually made of metal or a composite resin that looks tooth-colored. Indirect dental fillings are inlays, onlays, and crowns. These filling options typically require more than one visit, because the dentist must take impressions of the affected area to create a stable restoration for the patient.What 5 metals are used in an amalgam filling? ›
Dental amalgam is a dental filling material used to fill cavities caused by tooth decay. Dental amalgam is a mixture of metals, consisting of liquid (elemental) mercury and a powdered alloy composed of silver, tin, and copper.Is resin-modified glass ionomer better than glass ionomer? ›
Whereas traditional glass ionomer cements were opaque, newer resin-modified glass ionomers have attained a much better esthetic match to dentin and enamel. In clinical studies, resin-modified glass ionomers have greater longevity than conventional glass ionomers for class II restorations.What is Type 3 glass ionomer cement used for? ›
Glass ionomer cements are classified based on what they are used for. Type I giomers are used as adhesives for attaching dental crowns, bridges and prostheses. Type II are used as restorative materials, and type III are used for lining and sealing.Which is better glass ionomer or composite? ›
While they are less durable than harder wearing fillings, like silver amalgams or gold fillings, composite fillings are significantly more durable than its glass ionomer counterpart. The downside being, after many years of use composite fillings can chip.What type of dental material is used for an intermediate restoration? ›
IRM restorative is a polymer-reinforced zinc oxide-eugenol composition restorative material designed for intermediate restorations intended to remain in place for no longer than one year. IRM restorative may also be used as a base under restorative materials and cements that do not contain resin components.What is intermediate restorative material made of? ›
IRM® Caps™ intermediate restorative material powder is composed of zinc oxide and PMMA powder (polymer reinforced). The liquid is eugenol with acetic acid added. IRM® is a reinforced zinc oxide-eugenol composition for intermediate restorations lasting up to one year.What material is IRM? ›
IRM® is a reinforced zinc-oxide eugenol (ZOE) composition for intermediate restorations lasting up to one year. It can also be used as a base under nonresin restorations.Can you use IRM as a base? ›
IRM may also be used as a base under cements and restorative materials that do not contain resin components, such as amalgams, and inlays and onlays. Its strength properties approach those of zinc phosphate cement. IRM has excellent abrasion resistance, good sealing properties and low solubility.