dental composite

dental composite fillings- composition, direct&indirect, clinical application,

1. Dental composite fillings

2. introduction

3. definition

4. history

5. timeline During the first half of the 20th century, silicates were the only tooth coloured esthetic material available for cavity restoration. Acrylic resins similar to those used for custom impression trays and dentures replaced silicates during the late 1940s and the early 1950s because of their tooth like appearance , insolubility in oral fluids, ease of manipulation and low cost. In 1956, Dr. R.L. Bowen developed a polymer based on dimethacrylate chemistry. This polymer was generally known as Bis -GMA or Bowen resin, was made up from the combination of bisphenol – A and glycidyl methacrylate. 1956 - Bowen Resin 1960 - Traditional or Macrofilled composites  1970 - Mircofilled and Light initiated composites  1980 - Posterior composites  1990 - Hybrid , Flowable , Packable , Compomers  2000 - Nanofilled composites

6. Composition As with other composite materials, a dental composite typically consists of a resin-based oligomer matrix , such as a bisphenol A- glycidyl methacrylate (BISGMA), urethane dimethacrylate (UDMA) or semi-crystalline polyceram (PEX), and an inorganic filler such as silicon dioxide (silica). Without a filler the resin wears easily, exhibits high shrinkage and is exothermic. Compositions vary widely, with proprietary mixes of resins forming the matrix, as well as engineered filler glasses and glass ceramics. The filler gives the composite greater strength, wear resistance, decreased polymerisation shrinkage, improved translucency, fluorescence and colour , and a reduced exothermic reaction on polymerisation . It also however causes the resin composite to become more brittle with an increased elastic modulus. Glass fillers are found in multiple different compositions allowing an improvement on the optical and mechanical properties of the material. Ceramic fillers include zirconia-silica and zirconium oxide .

7. composition Matrices such as BisHPPP and BBP, contained in the universal adhesive BiSGMA , have been demonstrated to increase the cariogenicity of bacteria leading to the occurrence of secondary caries at the composite-dentin interface . BisHPPP and BBP cause an increase of glycosyltransferase in S. mutans bacteria, which results in increased production of sticky glucans that allow S.mutans ' adherence to the tooth. This results in a cariogenic biofilms at the interface of composite and tooth. The cariogenic activity of bacteria increases with concentration of the matrix materials . BisHPPP has furthermore been shown to regulate bacterial genes, making bacteria more cariogenic, thus compromising the longevity of composite restorations. Researchers are highlighting the need for new composite materials to be developed which eliminate the cariogenic products currently contained in composite resin and universal adhesives. A coupling agent such as silane is used to enhance the bond between these two components. An initiator package begins the polymerization reaction of the resins when blue light is applied. Various additives can control the rate of reaction.

8. Depending on the filler particle size, we find the following types of dental composite: Macrofill composites The first dental composites that were used in dentistry were determined by their macro filling. They are so called because their size was 15 to 100 micrometers. On the other hand, nowadays, simple particles of 2 micrometers are considered macroparticles . These composites were very resistant, but their surface roughness, difficult polishing and poor clinical performance limited their use until they became obsolete. Fortunately, to deal with this aesthetic issue, microfiller composites soon emerged.

9. Microrefill composites These composites have a more appropriate particle size: 0.4 micrometers. Their reduction, together with their natural translucency and high degree of polish, make for exceptional aesthetics. However, they are limited to the anterior sector, where the masticatory stresses are lower than those of the posterior sector. A good example of microrfilled composite is Heliomolar from Ivoclar Vivadent , available in syringe , capsules or in fluid composite

10. Microhybrid composites Another type of dental composite is the hybrid, characterized by mixing different sizes in its composition, this offers the best of both in dental resins. Hybrid composites can be described as small particle macro-fill composites (0.6 - 5 micrometers), with a microfiller of 0.04 micrometers incorporated into the resin matrix. This combination of particles improves the transfer of tension between particles, conferring unique and superior properties. These microhybrids are universal composites, and can be used in both anterior and posterior restorations, thanks to their impressive combination of strength and polishability , wear and fracture resistance, and versatile clinical handling. An example of a microhybrid composite with a very high degree of polish and strength is Ultradent's Amelogen Plus., available in a 2.5 gram syringe.

11. Nanorellene composites The nanorelleno is one of the most advanced choices in the field of dentistry. Nanotechnology has made it even more possible to reduce filler particles to nanometric dimensions. Composites formed by nanoparticles have exponentially improved their mechanical and aesthetic properties, such as abrasion resistance, surface smoothness, and the final finish result. An example of this composite is Voco's Grandio . This composite, available in a syringe, consists of nanoparticles between 25 and 60 nm and particles with an average size of 0.7 microns.

12. In the world of composites, particle size matters a lot.

13. colour The composite is a synthetic material that adheres to the tooth surface for a perfect filling of the tooth. However, emulating the natural dentition to achieve an imperceptible restoration and great aesthetics, and adapt the colour through three aspects: tone , saturation and value , are other main objectives. Tonality or hue is the name of the colour , i.e. the specific type of wavelength. Today, most resinous systems use the classification Vita to identify shades. In it we can find four classical shades: A. Brown - Reddish. 80% of patients B. Orange - Yellow C. Grey - greenish D. Grey - Pink. Corresponding to 5% of people, and used more specifically for characterizations. The tone of the dentine which is to be considered basic among the dentin elements, is recorded at the level of the central part of the vestibular cervical third. This is where the least amount of enamel can be found, but a large volume of dentine can be found. On the other hand, the shade of the enamel should be recognized at the level of the middle third of the teeth, where it is generally two or three shades lighter than the one chosen for the dentine.

14. vita https://www.youtube.com/watch?v=Qrn83wLuvAU

15. Advantages

16. disadvantages

17. Direct dental composites Direct dental composites are placed by the dentist in a clinical setting. Polymerization is accomplished typically with a hand held curing light that emits specific wavelengths keyed to the initiator and catalyst packages involved. When using a curing light, the light should be held as close to the resin surface as possible, a shield should be placed between the light tip and the operator's eyes. Curing time should be increased for darker resin shades. Light cured resins provide denser restoration than self-cured resins because no mixing is required that might introduce air bubble porosity. Direct dental composites can be used for: Filling cavity preparations Filling gaps (diastemas) between teeth using a shell-like veneer or Minor reshaping of teeth Partial crowns on single teeth

18. Setting mechanisms of resin composite Types of setting mechanisms: Chemical cure (self-cure / dark cure) Light cure Dual cure (setting both chemically and by light) Chemically cured resin composite is a two-paste system (base and catalyst) which starts to set when the base and the catalyst are mixed together. Light cured resin composites contains a photo-initiator (e.g. camphorquinone ) and an accelerator. The activator present in light activated composite is diethyl-amino-ethyl-methacrylate (amine) or diketone.They interact when exposed to light at wavelength of 400-500 nm, i.e , blue region of the visible light spectrum. The composite sets when it is exposed to light energy at a set wavelength of light. Light cured resin composites are also sensitive to ambient light, and therefore, polymerisation can begin before use of the curing light. Dual cured resin composite contains both photo-initiators and chemical accelerators, allowing the material to set even where there is insufficient light exposure for light curing. Chemical polymerisation inhibitors (e.g. monomethyl ether of hydroquinone) are added to the resin composite to prevent polymerisation of the material during storage, increasing its shelf life. A hand-held wand that emits primary blue light is used to cure the resin within a dental patient's mouth.

19. Indirect dental composites Indirect composite is cured outside the mouth, in a processing unit that is capable of delivering higher intensities and levels of energy than handheld lights can. Indirect composites can have higher filler levels, are cured for longer times and curing shrinkage can be handled in a better way. As a result, they are less prone to shrinkage stress and marginal gaps and have higher levels and depths of cure than direct composites. For example, an entire crown can be cured in a single process cycle in an extra-oral curing unit, compared to a millimeter layer of a filling. As a result, full crowns and even bridges (replacing multiple teeth) can be fabricated with these systems. Indirect dental composites can be used for: Filling cavities in teeth, as fillings, inlays and/or onlays Filling gaps (diastemas) between teeth using a shell-like veneer or Reshaping of teeth Full or partial crowns on single teeth Bridges spanning 2-3 teeth

20. Method and clinical application Today's composite resins have low polymerization shrinkage and low coefficients of thermal shrinkage, which allows them to be placed in bulk while maintaining good adaptation to cavity walls. The placement of composite requires meticulous attention to procedure or it may fail prematurely. The tooth must be kept perfectly dry during placement or the resin will likely fail to adhere to the tooth. Composites are placed while still in a soft, dough-like state, but when exposed to light of a certain blue wavelength they polymerize and harden into the solid filling . It is challenging to harden all of the composite, since the light often does not penetrate more than 2–3 mm into the composite. If too thick an amount of composite is placed in the tooth, the composite will remain partially soft, and this soft unpolymerized composite could ultimately lead to leaching of free monomers with potential toxicity and/or leakage of the bonded joint leading to recurring dental pathology. The dentist should place composite in a deep filling in numerous increments, curing each 2–3 mm section fully before adding the next . In addition, the clinician must be careful to adjust the bite of the composite filling, which can be tricky to do. If the filling is too high, even by a subtle amount, that could lead to chewing sensitivity on the tooth. A properly placed composite is comfortable, of good appearance, strong and durable, and could last 10 years or more.

21. Method and clinical application The most desirable finish surface for a composite resin can be provided by aluminum oxide disks. Classically, Class III composite preparations were required to have retention points placed entirely in dentin. A syringe was used for placing composite resin because the possibility of trapping air in a restoration was minimized. Modern techniques vary, but conventional wisdom states that because there have been great increases in bonding strength due to the use of dentin primers in the late 1990s, physical retention is not needed except for the most extreme of cases. Primers allow the dentin's collagen fibers to be "sandwiched" into the resin, resulting in a superior physical and chemical bond of the filling to the tooth. The enamel margin of a composite resin preparation should be beveled in order to improve the appearance and expose the ends of the enamel rods for acid attack . The correct technique of enamel etching prior to placement of a composite resin restoration includes etching with 30%-50% phosphoric acid and rinsing thoroughly with water and drying with air only. In preparing a cavity for restoration with composite resin combined with an acid etch technique, all enamel cavosurface angles should be obtuse angles .

22. Step by step

23. A) Shade selection . Dental bonding comes in a variety of colors, and an appropriate one will need to be chosen for the restoration being created. The dentist will use their shade guide (it contains samples of each of the different colors of bonding they have to choose from) to see which shade matches the part of their patient's tooth they are working on the closest. They'll simply hold each sample tab next to the tooth and compare its color, and level of translucency (if this option is available). They may choose a separate composite for different layers (internal vs. surface) or portions (body of the tooth vs. biting edge) of the restoration they're creating. Doing so can greatly affect how natural it will look. Selecting a shade of composite for a tooth's restoration.

24. B) Cleaning the tooth . A strong bond can't be formed unless the tooth's surface is clean. The dentist will polish the tooth to remove any debris that's accumulated (dental plaque, tartar, etc .

25. C) Tooth preparation (drilling and trimming). The amount of tooth shaping that will be needed for any specific restoration will vary. With some cosmetic applications (closing tooth gaps, repairing minor chips, possibly even veneering the front surface of the tooth), little to no trimming may be needed. The exposed tooth surface that the restoration will be bonded to will be primarily enamel. At the other extreme, like a restoration that's needed to repair the damaged caused by tooth decay, the amount of drilling required may be relatively extensive. It's commonplace that with this type of restoration both a tooth's enamel and dentin layers are involved. The preparation has penetrated the tooth's enamel layer and the underlying dentin is exposed. Gif!

26. D) Acid etching the tooth's surface. Once the tooth has been trimmed (if needed), the actual bonding process is begun. The first step involves etching the tooth's exposed surfaces with an acidic "tooth conditioner." The conditioner is usually a gel (that comes in small syringes). It normally contains 30 to 40 percent phosphoric acid. The conditioner is spread out over the tooth where the bonding will be placed. It's allowed to sit for at least 15 seconds (possibly more) and then is thoroughly washed off. Tooth's surface has now been prepared and is ready to receive the dental bonding. (If the dentist were to dry the tooth at this point, its etched enamel surface would have a frosted appearance, much like the appearance of etched glass.) This step prepares the tooth's surface so the bonding will adhere.

27. E) Applying the bonding agent. The dentist will now paint or dab "bonding agent" (a liquid plastic) onto the etched tooth surface using a small brush or applicator. Sometimes they'll also blow air gently over the tooth so to ensure that the bonding agent has been dispersed as a thin even layer over the tooth's entire preparation and etched surfaces.

28. F) Curing the bonding agent. Once the bonding agent has been applied, the dentist will shine a "curing light" on it. The light from one of these units is usually blue in color. It activates a catalyst in the bonding agent that causes it to harden. It takes about 10 to 20 seconds of exposure. An initial bond to the tooth has now been created. The bonding agent has established a micromechanical bond with the tooth's etched surface. Applying and curing the bonding agent.

29. G) Creating the restoration. / Applying composite restorative. Now that an initial bond has been established with the tooth's surface (by way of the bonding agent), successive layers of dental composite are added, so to give the restoration its needed bulk and shape. As each one is added and set, it creates a chemical bond with the bonding agent layer and/or previously placed layers of composite. Composite has the consistency of putty. The dentist will apply it in small portions and gently pat each into place, until that part of the restoration that they're currently building has the needed shape.

30. Curing the composite . Once the dentist is satisfied with the positioning of the dental composite, they'll initiate its set using the same curing light they used to set the bonding agent. Usually, somewhere between 10 to 40 seconds of exposure time is needed, in some cases possibly more. Applying and curing the dental composite .

31. Building up the restoration . If after the placement of the initial amount of dental composite the shape of the restoration is not yet complete, the dentist will simply need to add additional layers. Each one is usually limited to about 2 mm in thickness (that's just a little bit thicker than a dime). And as each is placed, it's fully cured before the next one is added.

32. Why a layering technique is used ? One reason why dentists tend to place composite as multiple thin layers instead of just one lump is that the light emitted from a curing unit can only penetrate through so much thickness at a time. If a layer is too thick, it won't get fully cured. Factors involved in how much thickness is permissible include the intensity of the curing light that the dentist owns, and the color/translucency of the layer of dental composite being placed. Another reason has to do with the fact that as composite sets, on a microscopic level it shrinks (dentist refer to this as "polymerization shrinkage"). Keeping each layer thin helps to keep the cumulative effect of this distortion to a minimum (as compared to placing and curing the same total thickness of composite as a single lump).

33. H) Trimming and shaping the restoration. A dentist will usually purposely over bulk a restoration and then use their drill to trim it back to the proper shape. As the dentist sculpts the composite, they'll use successively finer and finer grit polishing stones, burs, discs, and strips until a very smooth and shiny polish has been achieved. Shaping and polishing the restoration.

34. I) The dentist will check the patient's "bite." At this point, even though the placement of the tooth bonding has been completed, it's still very important for the dentist to check the patient's "bite." They'll need to evaluate how their patient's teeth come together and whether or not the restoration they have just placed interferes with this motion. Carbon paper . To do this, the dentist will place a thin strip of carbon paper between the patient's teeth and ask them to close gently and then make a motion where they slide their teeth against each other. The paper will create marks on those points where the patient's opposing teeth touch. If marks are observed on the new restoration, the dentist will adjust the bonding's thickness until further testing demonstrates that it has the proper form.

35. J) The final polishing . Now that everything has been adjusted, the dentist will give the new restoration a final buffing and polishing. Once this has been completed, it's finished and ready for use. The first step of finishing and polishing involves checking and/or correcting the shape of the tooth. The shape is responsible for the symmetrical proportion and integration of the restoration with the various teeth. To check the shape we have to observe the angle lines, which divide the plane area of ​​a large reflection light (between the angle lines) and the shadow area, which lies outside the angle lines and is rounded. The polishing pastes should be applied with a felt disc or a soft brush, to not scratch the surface of the composite resin (ex. Flexibuff , Cosmedent ). To give to the composite resin a natural appearance of enamel gloss, it is recommended to use a low-grade diamond pastes or aluminum oxide pastes

36. Ps. In the presentation are prest GIF images - to play them you have to run presentation and wait 5 sec 

37. OPG RTG Replacement of old fractured and discolored fillings i.r.t 14 using composites. Composite restoration i.r.t 15.

38. Post-operative Orthopantomogram (OPG) showing three layers of restoration consist of indirect pulp therapy/calcium enriched mixture, glass ionomer and composite resin. Left: Higher magnification of treated first lower left molar revealing well defined periapical radiolucency of both roots

39. 17 – composite fillings

40. sources https://www.deltadentalins.com/oral_health/amalgam.html https://en.wikipedia.org/wiki/Dental_restoration#Glass_ionomer_cement https://en.wikipedia.org/wiki/Dental_composite#History_of_use https://en.wikipedia.org/wiki/Dental_composite https://www.verywellhealth.com/different-types-of-fillings-1059018 https://www.peartreedentalcare.com/blog/amalgam-vs-composite-fillings-which-is-better/ https://www.webmd.com/oral-health/guide/dental-health-fillings#1 https://www.dentaltix.com/en/blog/dental-composites-frequently-asked-questions https://oasisdiscussions.ca/2016/02/09/crs/ https://www.animated-teeth.com/tooth-bonding/a32-dentist-composite-fillings.htm https://www.slideshare.net/UDDent/direct-aesthetic-restorative-materials https://www.slideshare.net/Hazharahmed93/composite-restoration