Direct Coronal restorations of frontal teeth:
Stratification technique of veneers.
Written by: Roland R.
Table of contents:
1. Introduction 1.1 Indications 1.2 Contraindications 1.3 Advantages 1.4 Disadvantages
2. Direct anterior restorations: Stratification Technique 2.1 Shade Determination 2.2 Restoration Materials 2.3 Mock-up 2.4 Matrixes 2.5 Dental Preparation 2.6 Stratification Method
3. Conclusion 4. References
1. Introduction The success of free-hand direct composite restorations in anterior teeth depends on a harmonious integration of various elements, including a thorough understanding of natural function, aesthetics, characteristics of current materials, and restorative techniques. The selection of composite brands that offer a variety of shades and provide seve ral opacities is mandatory. By utilizing an anatomic stratification with successive layers of dentin, enamel, and incisal composite, a natural-appearing aesthetic result can be achieved in a relatively simple and predictable manner. Attentive use of finishing methods is still necessary for surface quality and natural appearance of the final restoration. Direct composite bonding remains an adequate therapeutic modality in traditional Class III to Class V and localized cosmetic restorations. It can satisfy most aesthetic demands, and it offers an affordable alternative to more invasive procedures, such as ve neers and crowns.
1.1 Indications In many cases the direct adhesive technique is highly favorable to the patient and the dentist, not only due to it being applicable in a single-appointment without the nee d of a technician, it is also minimally invasive, highly esthetic and long lasting if the procedure is performed properly. Although reports have been recorded of restorations lasting for 10 to 15 years, this highly depends on the working technique and the dentist’s experience. Todays dentistry, direct restorative procedures are frequently used. It varies from restoring carious lesions such as Black´s cavity class III, I V and V to restoring dental dyschromias. This technique is also used for more extensive restoration such as reshaping microdontic teeth, restoring teeth with diastemas, or to simply satisfy the patient’s need to obtain an esthetic smile.
1.2 Contraindications of Direct Composite Veneers The contraindications for the direct and indirect techniques include: patients with a deficient oral hygiene, patients presenting oral breathing, free dentin across a larger surface, vestibular positioning of teeth, extensive carious lesions, non-favorable occlusion and patients that will cause e xcessive stress upon the restoration.
1.3 Advantages In the hands of a skillful dentist, the com posite veneer can be used to creat e a beautiful and natural looking tooth. It costs less than a c eramic veneer and usually only requires one appointment to complete. If the veneer brakes or chips, it can be repaired. Huge selection of color and shades can be used to the patients satisfaction. To add up the advantages of an composite veneer, they are functional, economic, ergonomic, esthetical, mechanical and biological.
1.4 Disadvantages The first and foremost disadvantage is that the proce ss cannot be altered once the hard dental structure
has been prepared. It requires skill and experience by the dental practitioner to achieve natural results, due to the use of different layers and colors of composite. Achieving the desired re sults often occurs through the means of trial and error, and may take excessive amounts of time to perfect. The finishing and polishing of the restoration is imperfect and deterioration of the composite is an important factor. The composite material used is a plastic and plastic will change in color over time. The bonding material used will also stain in time. There is a risk of the direct veneer to come off if improper technique was used to place the veneer. In time the junction between the restoration and tooth structure will become visible due to discoloration.
2. Direct veneers Stratification Technique
2.1 Shade Determination Analogous to natural tooth tissue, the appearance of dental restorations is influenced by shape, surface texture, translucency/opacity, value, chroma and hue, with eac h property combining to affect the final outcome. While shape and surface texture are still considered of greatest importance, predictable shade matching is an essential requirement for all practitioners and a number of techniques are available to facilitate this process. Shade guides
While shade guides are included with most composite systems, unfortunately they are generally considered to be inaccurate and unsuitable for precise colour matching for a number of reasons:
The majority of shade guides are not fabricated from the restorative material that they represent;
Shade guides are generally less translucent than natural te eth and restorative materials;
Most shade tabs are of standard thickness;
Composite nomenclature can be confusing, for example, dentine, body and opaque shades may be synonymous;
There is poor correlation between composite shades and those used for dental ceramics;
Composite resins frequently undergo a significant shade change during polymerization;
Set composite resin material absorbs water post-operatively and this may result in unpredictable colour changes;
Various techniques have been described that aim to overcome the limitations of commercially available shade guides and include:
Placing a sample of the material(s) on the tooth surface (or a suitable adjacent tooth). Ideally, use the same quantity required for the restoration and the test sample should be light-cured to account for polymerization shade shift;
Chairside construction of customized shade guides made from genuine materials, which may be layered in various thicknesses
Practice prototypes copying anticipated proportions of definitive restorations
Purchase of materials with innovative two component shade guides,
Purchase of systems containing shade guides fabricated from composite,
Shade-taking technique
Various technique tips have been identified to improve precision when selecting shades for direct (and indirect) restorations, including:
Shade should be taken immediately at the start o f restorative procedures before dehydration has occurred (see below);
Study cavity configuration and anticipate optical requirements of the final restoration, ex. cavities extending from labial to palatal surfaces must transmit light in the same way as the adjacent tooth tissue;
Assess (or measure) the cavity with regard to the relative quantities of missing enamel and dentine
Note any discolorations that will require masking with opaque material
Where both enamel and dentine are exposed, take the shade of both
When assessing control teeth, use the middle t hird to record the basic shade
Take shade quickly. (After five seconds staring at a tooth o r shade guide subtle colours blend)
Look away at a complementary colour, ex. blue to re-sensitize the eyes to the yellow/orange/red spectrum
Use different lighting sources to avoid metamerism, where coloured objects appear the same under one light source and different under another
Use a colour-corrected light source to select hue and chroma
Use less bright light to select value
Colour mapping
As enamel loses water rapidly, shade selection should be carried out as early as possible and before isolation. Dehydration blocks the passage of visible light and this decrease in refractive index causes enamel (and dentine) to become lighter and more opaque, in less than three minutes. Maximum dehydration is reported to occur 30 –45 minutes after isolation and complete rehydration may not occur for 24 –48 hours. Dehydration also masks the internal colour characteristics. For these reasons, experienced practitioners refer to a pre-operative photograph or diagram of well-hydrated teeth to guide their placement sequences. This is commonly referred to as a colour map. A good photograph used with an appropriate shade guide is reported to be the most precise method of colour communication. Digital images may be underexposed or manipulated with software to reveal characteristic internal features, particularly occurring in the incisal third.
Color map for single central Schwartz J. Shape of Color: Aesthetics from a Physiologic Perspective. http://www.dentistrytoday.com/aesthetics/7321-shape-of-color-aesthetics-from-a-physiologic-perspective. Dentistry Today: May 2012.
Colour Map Fahl N. A polychromatic composite layering approach for solving complex Class IV/Direct Veneer/Diastema Combination: Part II. http://www.heraeusvenus.de/media/downloads/us/clinicalarticles/4_Newton_200701ppad_fahl.pdf. January/February 2009.
2.2 Restoration Materials Obtaining the desired esthetic results depends on the c hoice and correct use, according to indications, of materials and working techniques adequate to each part icular clinical case. In this sense the value of materials is related to the physical-chemical properties, especially optical properties (multiple colour shades, opacity/translucence, colour stability), the maneuverability, the quality of final application, the polishing and finishing of surfaces, and the technique should permit the ability to obtain the form, the dimension and selection/realization/reproduction of natural coloristic aspect of restored teeth. The enamel-dentine adhesive systems constitute an important decision in the final result direct anterior restorations. Their current development and variability offers the possibility in obtaining a superior value of adhesive force, and optimal marginal seal, which ultimately increase the longevity of the restoration. The first existent and readily available composite resins used in prac tice were those with macrofillers; having an increasing degree of irregular packed macroparticles, with a less homogeneous distribution and ununiform in dimension, they present an increased resistance to mechanical stre ss, but they present decreased esthetic results, due to optical properties and the aspect of the surface texture achieved after finishing and polishing. Furthermore, due to these r easons, they are not a suitable solution for direct restoration of anterior teeth. In the direct restoration of anterior teeth, for the reproduction of enamel properties and the quality of its surface, from an esthetic and biological point of view, the composite materials most suitable that may be used are those based on microfill. These materials contain densely packed spherical microparticles, with a homogeneous distribution, uniform in dimension, which allow the achievement of an improved, long lasting luster of the re storation surface, and good resistance in the conditions of normal wear. Due to these physical pr operties, they provide an adequate reproduction of natural dental surface, in terms of texture and the absence roughness, reflection and refraction of light, colour density, as well as translucence, conferring to natural esthetic aspect of the final restoration. Furthermore, they do not favor the development of dental plaque due to the smoothness achieved by finishing and polishing. The principal downfall of microfill composite resin is their decreased resistance to fracture s or to accentuated wear, limiting their use when encountering such situations. Composite resins based on nanotechnology, with nanoparticles are the mo st recently developed for the use of direct esthetic restorations. Today, they are considered universal restoration materials for usual situations, where esthetic requirements are not exceptional, due to their increased maneuverability, decreased polymerization shrinkage, resistance to fractures, favorable optical properties for colour and a similar translucence of natural dental structures, a smooth, lustrous surface similar to enamel. Other than their use alone, they may be used together with microfill composites, in situations where the quality of translucence allows the reproduction of natural dental structures. Although composites containing nanoparticles ensure the above mentioned properties, they do not realize a surface with extremely close characteristics of natural teeth quasi identical to natural dental surfaces nor do t hey reproduce the natural esthetic aspects, comparing to microfill resin composites.
In conclusion to selecting the co rresponding material for direct esthetic anterior restorations, microhybrid composites are optimal for the reproduction and replacement o f dentine (resistance, colour, opacity), nanohybrid composites and those containing nanoparticles are mostly indicated as a universal material for common situations (with above average esthetic results), and microparticle composites can best imitate the character istic aspects of enamel (surface texture and shine, translucence, light reflection and refraction) meaning they are best suited from an esthetic point of view for its replacement.
2.3 Mock-up Composite mock-ups provide a method by which to evaluate the esthetic demands of a patient's dentition. The techniques of mock-up fabrication can be used as aids in both diagnostic and esthetic evaluation. When used diagnostically, they allow assessment either on study models or directly on unprepared natural teeth. When used for e sthetic evaluation, mock-ups can be placed directly on tee th, which are totally unprepared, partially prepared, or fully prepared for the final restoration. They can be placed immediately before the preparation appointment or in advance so the patient has a trial period in order to evaluate them functionally and esthetically. The end result is that the dentist is able to control the esthetic artistry from the beginning to the completion of treatment. Mock-up materials and techniques
Flowable composite, of any brand, is the mater ial of choice. It is easy to apply, flows readily, and sets with a smooth, esthetically pleasing appearance. Originally, regular composite was used but because of its tendency to lift off of surfaces as it is shaped, it was replaced with flowable which remains in place as it is sculpted. It can be applied as a thin veneer over study models or directly onto natural teeth. Where gross tooth reduction is required it can be layered into any desire d thickness. A fine-bladed carver can be used to shape the interproximal and gingival areas. Removing the overhead dental light source increases the working time. Afte r light curing a finishing bur is normally all that is needed for shaping. Parameters for esthetics
In esthetic cases the central incisor forms the essence of t he smile. The shape and position of the centr al incisor is dependent on the general parameter s of smile design. These can be dictated by basic prosthetic principles such as those used in determining denture tee th arrangements. Facial form dictates tooth form, lip line determines incisal length, and basic phonetics determine the incisal edge position. The angulation of the incisors, midline position, and gingival height are other factors that must be considered. Patient preference is another important factor in determining the final esthetic outcome. It may be determined by presenting to the patient a number of smile options. These may include: before and after photographs of previous cases, magazine covers showing smile varieties, and digitally enhanced photographs. Digitally enhanced smiles can be easily produced using computer programs, which allows the placement of a variety of smile options into a digital photograph of the patient.
Before presentation to the patient a diagnostic mock-up can also be prepared on st udy models. It will often reveal limitations in creating the idealized digital smile due to the patient's arch form or tooth position. The idealized computerization can then be presented to the patient along with the diagnostic model to demonstrate the limitations. The opportunity to visualize the treatment limitations enables the patient to make a more fully informed treatment decision. Diagnostic mock-up on study models
The preparation of a mock-up on a study model can be a very simple yet effective diagnostic aid to help in the overall diagnosis of a case. The amount of tooth reduction will often help determine whether orthodontic or endodontic intervention will be required. For the study model mock-up a bur is used to create a rough veneer preparation on the tooth to be treated. Composite is then flowed from mesial to distal in rows beginning at the gingival. In cases where the incisal is to be lengthened, t he operator places a finger lingual to the tooth and flows the composite up onto the finger. After setting with a curing light a bur is used to quickly shape the incisal to the desired length and form. In cases where the entire tooth is to be repositioned finger support on the lingual allows for incrementally set layers to be built up until the desired shape is achieved. By leaving the majority of the lingual surface unprepared the operator is able to dete rmine the gross labial reduction required at the preparation appointment simply by examining the study model. The mock-up aids in the overall diagnosis by helping determine the amount of tooth reduction necessary. Direct dental mock-up technique
The same technique used on study models can be used directly on teeth to be prepared for veneers when the length and or shape are to be altered. The amount of tooth removal is determined by the degree of change required in tooth shape or position. When moderate change is re quired, primarily to improve contours, rough veneer prep is first prepared on one of the central incisors. By removing just the depth of a veneer prep, the flowable composite bead of material extrudes from t he syringe tip in a thickness close to the thickness of the dental structure that was removed. The flowability of the material results in a very smooth surface after light curing which helps to reduce finishing time on t he labial. Ideally, the only finishing required should be to the incisal edge. This can often be accomplished without anesthetic. For the tooth requiring the most extensive modification such as in cases where the diagnostic mock-up indicates that endodontic treatment is required to reposition it, the preparation may involve removal of the majority of tooth st ructure. Rebuilding is then done in layers, which are individually light cured with lingual digital support -- the same technique used on study models. Immediately after the mock-ups are completed on the teeth they can be analyzed in relation to function and esthetics. In cases where the treatment was accomplished without anesthetic the incisal edge, lip position, and phonetic assessment can also be examined at this time. The same direct technique can be applied in some cases to unprepared teeth. The mock-ups allow the patient to visualize the proposed treatment. Mock-ups are placed on the unprepared teeth without bonding to give the patient an easily removable esthetic transformation.
Advantages of direct mock-up
One of the main advantages of direct moc k-ups of teeth prior to preparation is t hat they allow the dentist to determine the esthetic result directly on the patient. At times this can be done prior to anesthetic which allows for the visual checking of length and shape according to lip line, as well as phonetic evaluation of incisal edge position. The use of indirect mock-ups on study models allows both the visual confirmation of the practitioner's ability to treat cases in the manner he or she proposes, and the ability to assess computer generated images. Ultimately, mock-ups may be used to obtain guides/matrices for the finished restoration.
2.4 Matrices Today, the techniques for realizing direct composite restorations may use different types of guides, which aid in the reproduction of the finished mock-up and its coronal contours and proximal interdental contacts, depending on the clinical situations. Matrix technique
There is a variety of matrices designed for anterior composites restorations involving proximal surfaces. They are made from a number of translucent polyester materials, commonly referred to by t he brand name Mylar . They are available in a number of shapes including: full contour crown forms, strips and specially designed sectional matrices designed to facilitate restoration of the complex curvature of anterior teeth.3 Matrices should be secured with suitable wedges to minimize cervical excess, provide tooth separation and soft tissue control and stabilize the r ubber dam. Thin metal sectional matrices designed for posterior composites may also be used or ‘dead soft’ foil wrapped around adjacent teeth. A popular technique employs plumber’s tape (Polytetrafluoroethylene (PTFE) tape). This inexpensive, inert, non-sticky material is usually wrapped around adjacent teeth to protect them from etch, adhesive, and excess composite. PTFE tape is of neg ligible thickness promoting tight contact formation and it does not interfere with adaptation of silicone templates. The majority of authors which recommend and use composite materials for direct dental restorations, along with using guides (considered mandatory and routine in proximal restorations), the use of freehand sculpting techniques of the coronal morphology represents an essential component of t he final result quality, due to the allowance of creativity and obtaining the “artistic” component of this result.
2.5 Dental Preparation In certain clinical situations, tooth preparation may be avoided completely, for example fracture repair or diastema closure. Where preparation is necessary, it should be minimized and confined to the enamel to optimize adhesion and reduce the risk o f marginal staining. Natural cavity undercuts or pulp chambers/root canals of endodontically treated teet h may also be used to enhance retention. Particle air abrasion may be employed to clean cavities and increase the surface area available for micro-mechanical and chemical retention. I n certain clinical situations, it may be
necessary to bevel enamel margins to assist retention and to mask the transition between t he tooth structure and the restorative material. Opinion varies on the size and form (eg scalloping) of enamel bevels or whether discs, ultrasonic tips or rubber points should also be used to remove fragile enamel from preparation margins. In the case of class III and IV preparation of small or medium dimensions, which are only localized in the enamel, the adhesive cavity only needs have, ot her than concave walls, a circular marginal bevel of max 0.5 mm in width. If the incisive angle ne eds restoration, the shape, dimension and the method of creating the bevel is correlated to the esthetic aspect and extension of the restoration: extensive preparations justify a larger width of bevel, up to 1mm. The adhesion surface with the enamel should be as large as possible, in proportionality to the amount of st ress the restoration will be exposed to. To mask the restoration contours on the vestibular surface, any sharp angles of the beveled m argin should be polished and finished, in such a way that there is continuity between the prepared and the non-prepared portion of the dental surface. When preparing for the first time a class III cavity, it is advised to avoid the removal of the vest ibular portion of the marginal ridge, as it will be more esthetic; in the case of remodeling a cavity from a previous obturation, it is harder to prevent the extension of the preparation on to the vestibular surface. In this case, the indicated solution would be to create a smoothly beveled margin that extends vestibular. For vestibular class V cavity preparations, the be vel should be minimal in inclination and width, which is especially important for the surface continuity and visibility between the restoration material and the dental surface. In the case of hard dental structure lesions due to erosions or abrasion, often the dental preparation is not needed, only a regularization and finishing of the margins. Furthermore, along with the complete removal of irreversibly altered hard dental structures, any portion of unsupported marginal enamel should be removed due to unfavorable effects it may pose on the adhesion to the surface. Although, keeping a thin enamel layer, after application of composite obturation, will create the “prism effect.” Isolation
While use of a rubber dam is far from commonplace, it is ge nerally considered to be the optimum method of moisture control for adhesive restorative procedures. Following isolation with a rubber dam, stabilizing cord, wedges or floss ligatures may be used to optimize the seal and prevent the dam partially obscuring adjacent teeth which are being used to guide restoration shape. Another useful isolation technique for Class III, IV and V restorations involves the use of gingival retr action cord, which may be soaked in an astringent product.
2.6 Stratification Technique Despite technological advances in contemporary composite systems, the majority of practitioners use monochromatic materials for anterior composites. Such techniques are ideally suited for small cavities but they may deliver sub-optimal aesthetic outcomes in more aesthetically important areas. Although placement of successive increments helps to minimize the e ffects of polymerization shrinkage stress, aesthetic layering techniques are considered problematic and less predictable than those that use a single material. Errors in layer ing techniques result in restorations, which appear too translucent or opaque. The reproduction of a natural aspect of c olor, translucence, and surface texture is de termined by the propagation of light through the restoration; the composite mass applied on the remaining dental structures. To create a natural three-dimensional effect, the composite mass should have identical or similar optical properties as real enamel or dentine. In comparison to the natural tooth, the multiple morphological stratification application of composite materials of frontal restorations may be described as “predominantly dentine,” due to the increased volume of the central dentine nucleus in comparison to t he natural tooth. The thickness relationship of opaque dentine composites and translucent enamel s is the key to successful layering techniques. The overall outcome is determined by the propagation of light as it passes through these layers to create an illusion of depth, equivalent to that seen in natural teeth. But it must not be forgotten that composite resins with microparticles have a different light refraction index than natural prismatic enamel, and the application of the e namel composite layer in the same thickness as natural enamel will produce an accentuated gre y shade of the final restoration. Furthermore, the artificial enamel layer should be applied in approximately half the thickness of natural enamel, aver aging around 0.5 mm. Keeping in mind the similar optical properties of natural teeth, all restorations must present an e namel composite layer on their vestibular, oral or proximal surfaces. To avoid excessive marginal translucence effect, in the area between the restoration limit and the natural e namel layer, the composite base (more opaque) dentine layer should partially extend past the bevel of t he preparation margin, and the composite enamel layer covering this dentine mass must be very thin. A wide range of composite stratification techniques, of varying c omplexities, has been described. To ensure predictable, aesthetically pleasing results, layering concepts should be simple, standardized and reproducible. The following basic dual-shade and more complicated multi-layered (polychromatic) placement sequences are presented as methodical guidelines for all clinicians wishing to create more natural looking direct anterior composite restorations.
Dual-shade layering technique
Inexperienced practitioners are recomme nded to develop confidence in layering techniques by beginning with two material shades, as this simplified technique is reported to deliver an acceptable colour match in a large number of clinical situations. Following etching and adhesive application, an opaque dentine material is applied, shaped and lightcured. Most dentine restorative materials (and 80% of natural dentine) are in the shade group A and selection of the correct chroma is a key to success. Palatal, proximal and labial enamel increments are then layered, freehand over the o pacious central core at approximately half the thickness of residual enamel. Polychromatic layering technique
When aesthetic demands are high, the widely accepted stratification technique proposed by Lorenzo Vanini is recommended. As each clinical situation presents different aesthetic challenges, study of detailed atlases, describing the comprehensive range of layering options is highly recommended. The fundamental principle of polychromatic layering technique is to use different composite shades to replicate the layers seen in natural teeth, which is now described in stages. 1. Palatal enamel layer
As with all restorative procedures, functional integration is as important as that required for aesthetic blending. Restoration of guiding palatal surfaces using direct techniques presents challenges, but can be simplified by using a template constructed from a prototype restoration or a pre-operative mock-up. The initial palatal composite increment may be applied to a t emplate made of conventional silicone putty or specialized transparent material before or after insertion into the mouth. Once light-cured, the palatal shell, immediately establishes the three-dimensional form of the whole restoration. 2. Dentine layer
To avoid a monochromatic appearance, dentine lobes are restored using progressively chromatic increments. The dentine build-up should stop short of the incisal edge and should be shaped into lobes, leaving room for the incorporation of materials designed to r eplicate the appropriate optical properties of the incisal third. 3. Special features
These are very case specific. In natural teeth, they are generally optical properties of enamel, but materials aiming to mimic these features are ideally placed before the final enamel layer. ‘Painting’ these features on the surface layer often appears artificial, because it lacks the quality of depth and may wear off. When the translucent enamel material is subsequently applied and polished these features show through, producing very natural appearances, such as the incisal ‘halo effect’.
Materials designed to replicate special features may be divided into opalescents, characterizations and intensives and are usually applied in that order. 3.1 Opalescents
Opalescent materials are placed in spaces left between the dentine lobes and, if required, extended into mesial and distal proximal spaces. Opalescent composite transmits light more efficiently and is designed to reproduce the iridescent optical properties commonly seen in the incisal third. The deg ree of opalescence is judged by the amount of blue that the material shows under direct light and amber features seen under transmitted light. Two generalized groups of material may be used to create opalescent effects: t inted flowable materials or artificially achromatic enamel (AAE) composite, which is inherently pigmented and not keyed to the vita shade system. Either material may be used to impart various degrees of translucency and subtle hues, ranging through grey, blue, violet, amber, to milky white. Opaque resins are often necessary to mask discolorations and/or dark backgrounds when restoring anterior teeth. 3.2 Characterizations and intensives
Experienced clinicians are capable of precisely reproducing a diver se range of characterizations. Intensives are used to recreate white spots or patches in teeth found with hypoplastic and hypomineralization defects. White features vary in opacity extent and lack opalescence. A range of tinted conventional and flowable materials may be applied using suitable instruments or brushes or mixed to copy unusual colourations. It is recommended to use them sparingly to avoid obviously unnatural appearances and to refer to an adjacent tooth or a pre-operative colour map. 4. Labial enamel layer
The final layer generally comprises an enamel or incisal material with smaller average filler particle size with translucent (and often opalescent) optical properties that modify those of the underlying layers. It is advisable to minimize the time spent manipulating superficial increments to reduce t he risk of incorporating air bubbles, which may affect the optical proper ties and/or be revealed during finishing and polishing procedures. The final layer may be slightly overbuilt and then finished and polished to the correct incisal edge thickness. It is recommended that the total enamel thickness should be a maximum of half of the thickness of the natural enamel that it replaces (or maximum thickness of 0.5 mm) to prevent restorations being too translucent, too low in value and not life-like. 5. Light-curing
While various alternative light-curing regimes have been proposed, general recommendations include: regular equipment checks using appropriate light intensity meters; light-curing for a suitable duration (usually at least 60 seconds) from all angles; keeping the light tip as close to the material as possible and avoidance of premature polymerization by ambient light. A layer of translucent material, such as
glycerine, may be placed over final increment. This minimizes contact with oxygen which inhibits surface polymerization. 6. Shaping
Shape is the most important factor in the final appearance of an aesthetic restoration. It is therefore essential that the primary anatomical features of natural te eth are meticulously reinstated using appropriate burs, discs and finishing strips. Initial shaping may be carried out using red-stripe (30-40 μm) composite finishing burs. When shaping a single central incisor, the adjacent tooth should be studied to re-establish symmetry by making the reflective face of both teeth equal. Repositioning of transition lines can change the appearance of poorly shaped teeth, making them appear aesthetically pleasing even though their outline remains the same. Functional surfaces should be designed and contoured so that both t he restoration and tooth can tolerate the anticipated occlusal forces. In patients with parafunction, more fracture resistant, large particle, hybrid composite is recommended, which may be veneered with a more aesthetic/polishable microfill or small particle nano-hybrid material. The correct shape must be established before refinements are made; if this is not done the finishing and polishing process will tend to magnify any errors. 7. Finishing and polishing
Finishing and polishing are well-researched procedures and play an essential role in the way that light interacts with the restoration. The natural secondary and tertiary surface texture features may all be simulated in direct restorations, using a variety of e quipment, including:
Finer diamond or tungsten carbide composite finishing burs (yellow/white/purple stripe) to refine shape and correct marginal; plaque retention factor s
Medium finishing discs to smooth the restoration and refine line angles/transition lines;
Fine polishing discs to create the att ractive surface lustre seen in natural e namel;
Silicone rubber points and cups to introduce secondary anatomical features such as developmental grooves;
Abrasive finishing strips to remove proximal excess and refine emergence profiles;
Sharp instruments, eg scalpels or scalers to remove unbonded excess;
Tungsten carbide or coarse diamonds to create a ‘perikymata effect’ that increases the restoration’s value
Goat’s hair/chamois/felt wheels and brushes to develop a high shine after all other stages have been completed.
Specialized polishing pastes of varying particle size
A methodical approach is required to complete e ach finishing and polishing procedure before moving on to the next. Great care should be taken to avoid iatrogenic damage to tooth surfaces and adjacent periodontal tissues. Copious water spray and a light touch should be used as rotary finishing equipment can
generate significant heat. This may damage hard and soft dental tissues, restorative material, and adhesive interfaces or destroy finishing burs designed for multiple uses. Restorations should never be painted with adhesive agents containing solvents. Although this will deliver a shortlived shine, surface degradation will rapidly encourage stain formation. The time t aken to shape, finish and polish anterior composite restorations accurately will deliver reliable, aesthetic, long lasting restorations equivalent to those made from ceramic.
Above Images found at: Fahl Newton. Mastering Composite Artistry To Create Anterior Masterpieces. http://www.slideshare.net/theaacd/anterior-direct-restorations.AACD’s Journal of Cosmetic Dentistry: Winter 2011.
3. Conclusion Successful anterior composites are satisfying for both patients and clinicians. The time taken to study dental aesthetics and practice and re fine operative techniques2 (Figure 20) will be rewarded on a daily basis. Direct adhesive procedures have almost limitless potential to restore function and aesthetics, while preserving healthy tooth tissue and, as such, anterior composites are at the very forefront of contemporary minimally invasive aesthetic dentistry.
4. References 1. Societatea de Stomatologie Estetica din Romania. “Incursiune in Estetica Dentara”. Ed. Florin Lazarescu. Bucuresti: SSER, 2013. Print. 2. Delean, A. Curs 7 Suport Fatetare. Anul IV, Catedra Odontologie, Curs Cariologie, Cluj-Napoca. 3. Goldstein RE. “Esthetics in Dentistry”. Vol I, BC Decker Inc, 2002. 4. Christensen J. Gordon. “What is a venee r? Resolving the confusion.” JADA, vol. 135, November 2004. 5. Mackenzie Louis. “Direct Anterior Composites: A practical guide.” Dental Update: Restorative Dentistry, May 2013. 6. Dietschi D. Free-hand composite resin r estorations: a key to anterior aesthetics [Abstract]. Europe PubMed Central. 7. Porth Ronald. Restorative/Preventive Dentistry: The role of composite Mock-ups in Esthetic Planning. Oral health group: June 2003.
