Risk Factors and Treatment Fees for Implant Dentistry

Risk Factors and Treatment Fees for Implant Dentistry	August 2011
Get the facts from implant guru Dr. Carl E. Misch as he writes about implant dentistry today.
by Carl E. Misch, DDS, MDS, PhD (hc) Introduction Implant dentistry has become the most predictable method to replace missing teeth. However, treatment planning for implant dentistry is most often driven by the existing bone volume in the edentulous sites. This method is often problematic. In partially edentulous patients, more than 6mm of bone height is found in 40 percent of posterior maxillae and 50 percent of posterior mandibles. This percentage is further reduced to less than 20 percent of completely edentulous patients in either arch. The doctor and the patient often have an incentive to do treatment which is faster, easier and less expensive. The typical fees associated with treatment in implant dentistry are related to the number of implants and teeth replaced. Hence, a three-unit fixed partial denture supported by two implants is one-half the fee of a six-unit fixed partial denture supported by four implants. As a result, instead of bone grafts and posterior implants, distal cantilevers are often extended from anterior implants, since more vertical bone is found anterior to the maxillary sinus in the maxilla or the inferior alveolar nerve and mental foramen in the mandible. The primary cause of complications in implant dentistry is related to biomechanical factors, with too much stress applied to the implant support system. When implants are inserted into abundant bone volume and allowed to integrate for four or more months before loading, the surgical success rate is more than 98 percent. This success rate is not related to implant number, size or design. However, when the implant is occlusal loaded with the prosthesis, the failure rate might be greater than three to six times the surgical failure. For example, a meta-analysis reveals 15 percent failure rates (with several reports of more than 30 percent failure) when the implant prosthesis is occlusal loaded with implants shorter than 10mm, or when they are placed in softer bone. This failure most often occurs during the first 18 months of loading and is called early loading failure. Mechanical complications of the implant components or prosthesis outnumber surgical failures and many reports are more frequent than early loading failures. These complications include abutment screw loosening, uncemented prostheses and porcelain fracture. These complications are more often in bruxism patients, males, when opposing implant prostheses and with group function occlusion. All of the factors increase the amount of stress on the implant system (occlusal porcelain, cement, implant abutment screw and implant-bone interface). Biomechanical stress might also cause marginal crestal bone loss. Since the implant does not have a periodontal membrane as a tooth, the stress to the implant-bone interface is mostly to the crestal marginal bone. When the stress is beyond the bone physiologic limit, resorption might occur. The bone loss might increase the risk of anaerobic bacteria and peri-implantitis, or the surrounding soft tissues might shrink and result in poor cervical aesthetics. Hence, biomechanical factors can lead to early loading failure, mechanical complications and/or marginal bone loss around an implant. Stress Magnifiers Cantilevers on the prosthesis are one of the most significant stress magnifiers to the implant system. When used in the posterior regions, the greater bite force (up to five times greater than the anterior region), is further magnified and might increase the force on the implant system by three times. In order to eliminate posterior cantilevers, a bone augmentation is often indicated. Most bone augmentation procedures are not as predictable as implant integration in existing bone volumes. Bone augmentation often requires an additional surgery prior to implant placement. Additional training is required to learn bone augmentation procedures and the learning curve is longer and more difficult to become accomplished in these techniques. Complications related to bone augmentation are more common than implant surgery in existing bone volumes and might be more extensive and even debilitating to the patient. The discomfort following bone augmentation is usually more than occurs after implant surgery. An extended healing time of four to nine months might be necessary for the bone graft to mature, compared to implant healing in native bone. The costs associated with bone augmentation are often greater than the fees related to implant insertion. In addition, there are usually more implants and more teeth replaced after bone augmentation compared to situations when implants are inserted into existing volumes of the bone and teeth are cantilevered to the posterior regions. More implants and more teeth replacements further increase the cost to the patient. As a consequence of these considerations, the doctor and the patient are both motivated to use existing bone volumes for implants and restore fewer posterior teeth in the prosthesis, often with a cantilever. Risk Factors An example of the patient and doctor having incentive to perform procedures with higher risks is when a patient has four teeth missing in a posterior maxillary quadrant (two premolars and two molars), with a pneumatized maxillary sinus cavity. There are typically two treatment options. The first is to place two implants anterior to the sinus, which supports a three-unit prosthesis (with a first molar cantilever). A second option is to perform a sinus bone graft, the insertion of three implants (in the first premolar, first molar and second molar position) and to fabricate a four-unit restoration. Fees and Risk Factors The first treatment option is one-half the fee of the second option, since it doesn't require a sinus graft, has fewer implants and less teeth replaced. The first option is also faster and easier since a bone regeneration is not required. The patient undergoes one surgery and therefore experiences less discomfort. However, the second treatment option has three to four times better chance for long-term success, since it doesn't cantilever a pontic in the molar region. Since cantilevers increase the biomechanical force to the anterior implants, there is an increased risk of an unretained prosthesis on the first premolar (because of a tensile force to the retainer and cement is 20 times weaker to tension compared to compression). This results with one implant (the second premolar) supporting three teeth and the risk of overload and failure. The first treatment option more often has more bone loss from occlusal overload related to the increased biomechanical stress as a result of the cantilever (Fig. 1). In addition, the mandibular second molar might erupt past the plane of occlusion with the first option (since it only has one molar) and each protrusive mandibular movement would result in a lateral premature contact on the maxillary prosthesis. This bone direction increases the sheer force, and might even trigger parafunction. As a result, all complications related to stress are increased. Biomechanical-related complications often occur within the first few years of function. As a result, the patient expects the dentist to repeat the treatment for no charge. When the first option fails, the second treatment option might be selected, often from a different dentist, which is associated with a greater cost. As a result, the patient is more likely to bring litigation against the first treatment team in order to pay for the additional costs of the second treatment option. As a consequence of an increased risk of complications in the first treatment option, the fees for this option should be more than the second treatment option. In other words, the fee for services rendered should not only be based upon the sum of the number of implants and teeth in the prosthesis, it should also include the amount of risk associated with the treatment. A more basic example of charging for risk factors is the treatment for a crown on a maxillary central incisor compared to a mandibular molar. The time and technique for an anterior preparation, impression and transitional prosthesis is greater than to restore a mandibular posterior tooth. The risk that an anterior maxillary crown has to be redone because of gingival recession, shade selection, etc. is greater than the mandibular crown. Yet, most dentists charge the same fee for both procedures. The maxillary anterior crown has more risk, therefore the fee should be greater. Full-arch Restorations When a full-arch fixed implant restoration is the treatment for a maxillary arch, the number of implants is often the same as the mandible. For example, "all in four" is a common treatment option presented to the profession in either arch, along with similar fees for either arch to the patient. Yet, the maxillary fixed restoration is supported by softer bone. The hardness of the bone is related to its strength. The mandible more often has hard (strong) bone and the maxilla most often has softer bone. In fact, the posterior maxillary bone might be five to 10 times weaker than the hard bone of the anterior mandible. The maxillary anterior arch receives a force at a 12- to 15- degree angle during occlusion and up to a 30-degree angle in excursions. A 15-degree angled force increases the force component by 25.9 percent and a 30-degree force increases the force by 50 percent. The excursive forces in a maxillary restoration come from within the arch to push outside the arch. This force direction on an arch is more detrimental than in the mandible. The mandible receives a force from outside of the arch toward the inside of the arch, which is the direction of force the arch was designed to resist. The maxillary arch usually has shorter implants than the mandible (since the vertical height of bone is less compared to the anterior mandible). The shorter implants have less surface area and higher stresses, especially in soft bone. A literature review reports a failure rate three times higher in full-arch maxillary implant fixed restorations compared to full-arch implants and a mandibular restoration. Aesthetic retreatments and speech complications are more often observed in the maxillary restoration compared to the mandible prosthesis. The air can escape between the residual ridge and prosthesis, and aesthetic requirements for the patients are primarily obtained by the maxillary restoration. In other words, the maxillary full-arch restoration should be treatment planned differently and cost more than a similar restoration in the mandible. To compensate for the softer bone and higher biomechanical stress, the maxillary arch should more often have bone augmentation (to eliminate posterior cantilevers), more implants inserted and higher prosthetic fees than a mandibular arch. The fees for an implant treatment plan that has fewer implants and/or cantilevers should be greater than restorations supported by more implants and/or without cantilevers (Figs. 2-8). Summary The fees associated with implant surgery and prosthetic rehabilitation should be related to the risks related to the treatment. The treatment plan in implant dentistry should have a biomechanical rationale to decrease stress to the implant system. The risks in dentistry are a factor which should be included in the cost of most all procedures that are associated with greater complications. The implant and associated restoration is not a commodity in which the cost is solely related to the number of implants and prosthetic units. References 1. Goodacre CI, Bernal G, Rungcharassaeng K. Clinical complications with implants and implant prostheses. J Prosth Dent 90: 121- 132, 2003.
Author’s Bio
Carl E. Misch, DDS, MDS PhD (hc) is the professor and director of Oral Implantology at Temple Dental School in Philadelphia, Pennsylvania; and director at Misch International Implant Institute in Beverly Hills, Michigan.
Call Now San Francisco Dentist Request for appointment at: (415) 391 - 7751 450 Sutter street, Suite 1905 San Francisco, CA, 94108 http://malidds.com/

Cavity Preparations for Posterior Composite Resins

Cavity Preparations for Posterior Composite Resins
Read Dr. Karl F. Leinfelder's seasoned advice about working with composite.
The first attempt to substitute composite resins for amalgam restorations came nearly forty years ago. Two basic problems were identified. These included an unacceptable rate of wear and a higher incidence of caries as compared to amalgam. Furthermore the progression of caries under composites was appreciably greater than with amalgam. While the exact reason for the caries progression differential has not been identified it is interesting to note that the amalgam releases a number of ionic elements (silver, copper, tin, mercury) that might retard  the process of caries progression. Composite resins on the other hand possess no such attribute. Fortunately the problem of wear or loss of anatomic form has been essentially resolved. By reducing in part, the dimension of the filler particle and increasing the load rate, the wear of composite resins is essentially the same as amalgam which is approximately five microns per year. The problem of secondary caries still exists. The primary reason can be attributed to a less than ideal adaptation of the restoration to the margins of the preparation. The use of dentin bonding agents as well as flowable composites has contributed appreciably to a reduction in this clinical problem. In addition to all of these changes, modification of the cavity preparation has been most contributive to a successful posterior composite resin restoration. When composites were first used as a posterior restorative material the preparation most commonly used was designed for amalgam. Developed by G.V. Black the preparation was engineered to automatically incorporate most of the proximal region of the tooth containing the highest plaque concentration and bacteria count. Buccal and lingual extension of the preparation was limited so as not to considerably reduce the strength of the tooth itself. Extension of the preparation bucally and lingually would ensure that the margins of the restoration be positioned into an area of relatively low bacterial count. This is an important consideration since the margin of the amalgam at the time of placement averages 10 to 12 microns. Such an interfacial gap is great enough to allow the invasion of caries-producing micro-organisms. In the case of composite resins there is no such interface. The use of dentin bonding agents causes the restoration to become an integral part of the cavity preparation along the entire length of the margin. As a result, a well-placed posterior composite resin technically contains no gap or interface for microbes to enter. When caries was present in the mesial and distal pits of a maxillary premolar, Black recommended that the entire central fissure, as well as the two pits be included in the preparation. It was argued that since the caries rate was so high (100 years ago) restoration of the two pits only would be followed by caries in the central fissure. Today caries are less frequent than it was during the time of G.V. Black. Furthermore, oral hygiene (through education) is generally much improved over that of several decades ago. Incidentally the more conservative preparation (treatment of mesial and distal pits) involves far less removal of tooth structure than the more aggressive approach. Calculation of the amount of tooth structure removed under both conditions shows that the more conservative technique results in about 400 percent less tooth structure. In the case of the Class II cavity preparation it is also possible to save considerably more tooth structure by using a conservative approach. In general the proximal box of the preparation is narrower than that associated with conventional amalgam cavity preparations. Furthermore, the presence of caries does not dictate the proximal margins be extended into a contact-free zone of the adjacent tooth. Also the proximal box is not extended onto the occlusal surface by more than 2 to 2.5mm beyond the location of the proximal marginal ridge. Finally, the gingival margin should be at least 2mm from the cervical line. In the case of amalgam, the gingival margin is extended until the tine of an explorer passes through the space between the margin and the adjacent tooth. These reductions in dimensions of the cavity preparation amount approximately to a 200 percent savings of sound tooth structure. Reducing the size of the restoration is clinically important since there is a strong relationship between dimension and clinical longevity. The smaller the dimension of the restoration, the greater the potential for extended longevity. The proximal box of the cavity preparation needs special attention to prevent the potential for secondary caries. It can be identified as the Achilles' Heel of the Class II preparation. Occlusal stresses on or near the marginal ridge during mastication tend to force the proximal aspect of the restoration into the interproximal space. Release of the occlusal stress results in a return to the original location. The amount of displacement depends upon the modulus of elasticity of the composite resin which is twice as great as it is for amalgam (and therefore twice the deformation of amalgam). Displacement is also dependent upon how well the restoration is bonded to the floor of the proximal box. The deeper the proximal box, the less the amount of enamel along the gingival margin. While the immediate bond strength of dentin bonding agents is similar for dentin and enamel, those for dentin tend to decrease over a period of time. As the thickness of the enamel decreases along the gingival margin, a special technique has been suggested to resolve the problem. Based upon the recommendation of Professor Qvist from Norway, a glass ionomer liner about 2ml in thickness is placed over the gingival floor. Procedurally the entire preparation is bonded with a dentin bonding agent. At this point a glass ionomer such as Fuji II LC is placed over the gingival box. Fuji IX is also recommended but since it is self-curing it will take longer to set. Glass ionomers are excellent auxiliary restorative materials for a number of reasons. First of all they release fluoride ions from their surfaces. The glass ionomer fluoride ions are not only absorbed into the adjacent tooth structure but they kill microbes in the immediate vicinity. Secondly the glass ionomers effectively resist microleakage. This interesting clinical property is the result of a matched coefficient of thermal expansion between the glass ionomer and surface to which it is bonded. When the glass ionomer is completely surrounded by tooth structure and restorative material it is identified as a "closed sandwich." When one of the surfaces is exposed to the oral cavity (such as a glass ionomer on the gingival box) it is classified as an "open sandwich." One of the major differences between an amalgam and composite resin restoration is the location of the pulpal floor in the case of mesial and distal pit caries (i.e. maxillary premolar). In the case of amalgam, the floor of the preparation must consist of dentin. Retention is achieved by convergence of the preparation to the occlusal surface as well as micro-mechanical retention of the prepared tooth structure. Consider the amalgam as a free-floating restoration with well-defined (microscopic) spaces at the restoration/tooth interface. As the masticatory force is introduced to the surface of the restoration, the energy is transferred though the amalgam and onto the floor of the preparation. If the floor of the preparation consists of enamel the energy will be retransferred to the occlusal surface. Constant recycling of this energy could result in premature cracking and fracturing of the restoration. In the case of composite resin restorations, the depth of the preparation can be stopped short of the dentinal-enamel junction if the caries process also stops before the dentin is reached. In such a case the dentinal surface (floor of the preparation) acts an absorber of the masticatory energy thereby causing it to dissipate. Furthermore since the restoration is bonded to the enamel walls of the preparation, the entire tooth will serve to absorb the energy as well. An appreciable difference exists between the preparations for composite and amalgam restorations. Almost without exception those for composites are considerably more conservative than those recommended for amalgam. Based upon years of research and clinical use it can be stated that the greater the degree of  conservatism associated with the composite, the greater the longevity. Interestingly some of the conservatism associated with the composite has been transferred to the amalgam preparation A comparison of illustrations depicted in the original text by Dr. Black with some of the more current publications on cavity designs make this finding quite apparent. Author’s Bio Dr. Karl F. Leinfelder earned both his Doctor of Dental Surgery and Master of Science (dental materials) degrees from Marquette University. In 1983, he joined the School of Dentistry at the University of Alabama and is the recipient of the Joseph Volker Chair. He also served as Chairman of the Department of Biomaterials until 1994. Presently he holds positions at both universities; adjunct professor at University of North Carolina and professor emeritus at the University of Alabama. Dr. Leinfelder has published more than 275 papers on restorative materials, authored more than 150 scientific presentations, two textbooks on restorative systems and has lectured nationally and internationally on clinical biomaterials.
Call Now San Francisco Dentist Request for appointment at: (415) 391 - 7751 450 Sutter street, Suite 1905 San Francisco, CA, 94108 http://malidds.com/

How Does Tooth Whitening Work?

There are many ways to whiten your teeth — from whitening toothpastes and other products that can remove many surface stains for very little cost, to light-activated whitening techniques in a dentist's office that cost up to $1,000 and can produce dramatic results. All whitening techniques work in one of two ways: Bleaching procedures change your natural tooth color, usually anywhere from five to seven shades brighter. In-office (chairside) whitening and at-home (tray) whitening both rely on bleaching. Bleaches contain an active ingredient, most often carbamide peroxide or hydrogen peroxide in concentrations of 10-22%, which helps remove both deep and surface stains. There are significant cost differences between different bleaching procedures: A light-activated whitening session in a dentist's office, sometimes called chairside bleaching, can cost $500 or more and results in instantly and often dramatically whiter teeth. However, after a year or so of eating and drinking normally (coffee, tea, soft drinks), your teeth become slightly discolored again and develop new stains. With chairside bleaching, you have to pay the $500 to have white teeth again. A custom mouthpiece created by your dentist for in-home bleaching costs around $300, and you typically wear it several hours a day or overnight for two weeks. When you notice new staining, you just wear the mouthpiece again for a night or two to take the stains off. Over-the-counter products for whitening teeth (those found in a drugstore) include boil and bite tray application, whitening gels applied with a brush, and whitening strips in a price range of $10.00 to $45.00. Non-bleaching procedures work by physical and/or chemical action to help remove surface stains. All toothpastes rely on mild abrasion to remove surface stains between dental visits. Whitening toothpastes have special chemical or polishing agents that provide additional stain removal. A professional cleaning by a dentist or hygienist also uses abrasion and polishing to remove most external staining caused by food and tobacco. Everyone responds differently to different whitening procedures. Some people respond well to whitening toothpastes, while people with gray teeth or other serious discoloration may require porcelain veneers or bonding (discussed elsewhere in this section) to achieve the smiles they've always wanted. Only your dentist or hygienist can determine what's right for you. Copyright © 2002, 2003 Colgate-Palmolive Company. All rights reserved.

___________________________________________________________________

Call Now San Francisco Dentist
Request for appointment at: (415) 391 – 7751 
450 Sutter street, Suite 1905
San Francisco, CA, 94108
http://malidds.com/

Self-Adhesive Resin Cements

Self-Adhesive Resin Cements	August 2011
Dr. Robert Margeas presents the advantages of self-adhesive resin cements.
by Robert Margeas, DDS The proliferation of dental cements on the market today makes it important for dentists to have a solid understanding of their capabilities and indications. The wrong cement or the wrong technique can easily lead to problems ranging from postoperative sensitivity to debonding, which can cut into productivity and can also potentially sour the dentist-client relationship. Traditional materials can offer challenges, but in recent years, the introduction of the self-adhesive resin cement category has offered advantages in many different types of cases. The Challenges of Traditional Materials Conventional resin cements have been a popular choice in the past, albeit a technique-sensitive one. Because traditional resin cements typically necessitate the use of a bonding agent, it is not uncommon for the material to penetrate the dentin tubules and result in post-operative sensitivity.¹ Resin modified glass ionomer (RMGI) cements, while not associated with the same sensitivity issues as resin cements, come with their own drawbacks. These materials do not offer the same level of strength as resin cements, and also are not appropriate for some types of ceramic restorations due to the fact that they expand when seated and some can cause breakage of the restoration.² Previously, dentists often had to compromise by choosing between a material that did not offer great strength and a material that had a strong chance of causing sensitivity. In fact, the rate at which sensitivity was reported in the 1990s was cause for concern in the dental community, with one survey finding 37 percent of patients reporting sensitivity in the first year after crown placement. Even more concerning, up to 11 percent of the teeth treated in this study required endodontic treatment within the first year.³ As dentists know, a moderate to high level of post-operative sensitivity can be extremely frustrating for patients, with pain caused by anything from temperature variances to bite pressure. Several solutions have been proposed for this problem in conjunction with the traditional resin cement bonding technique, including or use of a self-etching primer and bonding agent.¹ However, the introduction of self-adhesive resin cements gave the dental community a much simpler way to prevent this issue. A Better Alternative Self-adhesive resin cements were initially introduced in 2002, with RelyX Unicem Self-Adhesive Resin Cement from 3M ESPE. This category was developed as an alternative to the traditional cementation options of conventional resin cement and RMGI cements. The introduction of self-adhesive resin cement offered dentists a new tool for cementation that had greater ease of use than the existing materials at the time, as well as this category combined technologies from glass ionomer materials, adhesives and composite cements to create a universal cement appropriate for a long list of indications, including inlays, onlays, crowns, bridges, posts, pins and screws made of ceramics, composite or metals.4 These materials also offered dentists the advantages of having choices of shades and translucencies, making them more useful and aesthetic for thin restorations, as opposed to the opaque look of older cements. To eliminate the need for etching, priming and bonding, this material was formulated with phosphoric acid modified methacrylate monomers, which enable the cement to self-adhere to the tooth surface. At the same time, the monomers also create a crosslinked cement matrix during radical polymerization, which contributes to greater mechanical and dimensional stability.4 These cements undergo a unique change from acidic to neutral from the time they are initially mixed to 24 hours after application, which is what enables them to adhere to tooth structure but also maintain long-term strength. For example, the original RelyX Unicem cement has a pH level of approximately 2 immediately after and also enables a high moisture tolerance. This low pH level and accompanying hydrophilicity allow the material to adapt well to the tooth structure. However, the cement quickly increases in pH value and after 24 hours achieves a neutral level of 7. At this pH, the cement is characterized as hydrophobic. This property makes it resistant to water uptake, helping prevent staining and cracking and adding to its long-term stability.4 In addition to their ease of use and strong mechanical properties, a primary advantage of this class of cements is the "near total elimination of post-operative sensitivity" reported with their use, thanks to their one-step demineralization and infiltration of dentin.5,6 These cements have become enormously popular in the past decade, thanks not only to the properties described above, but also their high bond strengths. An easy-to-use material is no advantage if it does not perform well. The bond strengths of self-adhesive resin cements make them well-suited for most indications.7,8,9 Choosing the Best Option As these materials have advanced – so too have their delivery systems – making them even more convenient to use in practice. Perhaps most convenient are automix delivery systems, which are available with several brands of these cements, including G-CEM Automix and Biscem Self-Adhesive Luting Cement. 3M ESPE has also recently introduced a second generation of its self-adhesive resin cement in an automix version – RelyX Unicem 2 Automix Self-Adhesive Resin Cement. This cement is based largely on the formula of the original, but with changes to its monomer makeup and filler particles, as well a new rheology modifier, all of which optimize the formula for use in an automix dispenser. Testing of the material has also shown increased mechanical properties and strong adhesion performance. In addition to automix dispensers, other dispensing alternatives include unit-dose capsules that are mixed in a triturator and dispensed onto the bonding surface, and a dual-chambered dispenser that automatically dispenses the proper ratios of the cement components so the dentist can then mix them on the pad.Dentists will find their individual preferences for each of these systems. In my own multiple-unit cases, I find automix systems are especially helpful. This delivery method is also very well-suited for root canal cases, as the dispensers are designed with small tips to fit directly in the canal. For a one- or two-unit case, a triturator capsule or clicker-style dispenser provides a convenient size and reliable mix.It's important to know the limits of any  material, however, and there are a few clinical situations in which I advise against the use of a self-adhesive resin cement. The most important is in a case with a non-retentive crown. In a case such as this, the etching, priming and bonding steps of a traditional resin cement are better suited to the situation. However, crowns with good retention can be very easily seated with self-adhesive resin cement. Dependability and Predictability Long-term results for self-adhesive resin cements have been excellent, with one five-year study showing a debonding rate of just 0.8 percent. The same study found just 1.8 percent of patients reported occasional temperature sensitivity.10 Another five-year study on post-cementation found similar success, with just one restoration failing during the period due to fracture of the abutment tooth.11 The long-term track record of this category of materials should be reassuring to dentists who seek products with proven safety and performance. Dentists are always in need of reliable and convenient materials that will serve patients well over long-term use. In the case of cements, there is certainly no shortage of material options, but the class of self-adhesive resin cements provides distinct advantages in many clinical situations. A material that offers such high performance and extreme simplicity of use is one that should have a valuable place in any operatory. References Christensen GJ. Resin cements and postoperative sensitivity. J Am Dent Assoc. 2000 Aug; 131(8):1197-9. Christensen GJ. Should resin cements be used for every cementation? J Am Dent Assoc. 2007 Jun; 138(6):817-9. Clinical Research Associates. Filled polymer crowns: 1- and 2-year status reports. CRA Newsletter 1998; 22 (10): 1-3. 3M ESPE. Technical Data Sheet: RelyX Unicem – Self-Adhesive Resin Cement in the Clicker Dispenser. http://solutions.3m.com/wps/portal/3M/en_US/3M-ESPE-NA/dental- professionals/  products/category/cement/relyx-unicem/ Christensen GJ. Why use resin cements? J Am Dent Assoc. 2010 Feb; 141(2):204-6. Guarda GB, Gonçalves LS, Correr AB, Moraes RR, Sinhoreti MA, Correr-Sobrinho L. Luting glass ceramic restorations using a self-adhesive resin cement under different dentin conditions. J Appl Oral Sci. 2010 Jun; 18(3):244-8. PD Dr. A Piwowarczyk, University of Frankfurt/Main, Germany, data submitted for publication, 2006. RelyX Unicem Technical Data Sheet. Prof Dr. M. Behr, University of Regensburg, data submitted for publication, 2006. RelyX Unicem Technical Data Sheet. Physical characteristics of new universal self-etching resin luting cements, E. Sakalauskaite, L. Tam, D. McComb, Restorative Department, Faculty of Dentistry, University of Toronto, Toronto, Ont. Canada; abstract #1894, AADR Orlando, 2006. 3M ESPE RelyX Unicem Self-Adhesive Universal Resin Cement 5-Year Clinical Performance. The Dental Advisor, No. 6, May 2008 M. Naumann, A. Franke, T. Dietrich, G. Sterzenbach. Rigid vs. Flexible Endodontic Posts: 5-Year Results of a RCT. Published in: IADR 2008, Toronto, #1607   Author Bios Dr. Robert Margeas received his DDS from the University of Iowa College of Dentistry in 1986 and completed an AEGD residency in 1987. He is an adjunct professor in the Department of Operative Dentistry at the University of Iowa. He is board-certified by the American Board of Operative Dentistry and is a fellow of the Academy of General Dentistry. He has authored numerous articles on implant and restorative dentistry and lectures on those subjects. He is the director of The Center for Advanced Dental Education and maintains a private practice in Des Moines, Iowa. He can be reached via e-mail at rcmarge@aol.com or by phone at 515-277-6358.

Direct Composite Restorations Just Got a Lot Easier

August 2011

Dr. Ara Nazarian describes a simplified technique to constantly restore posterior teeth with a new composite in a fast, easy and predictable manner.

by Ara Nazarian, DDS Over the years, the utilization of composite resin systems for intracoronal restoration of posterior teeth has increased dramatically with the improvements in physical and mechanical properties of these resin systems and patient demand for tooth-colored restorations. Restorative dentistry continues to evolve through innovations in these bonding systems and restorative materials that help the clinician establish proper function, shape, contour and color. Because of these advancements, contemporary restorative materials and techniques allow minimal preparation of tooth structure and improvement in the longevity and aesthetics of the restoration. There have been many different posterior composite techniques described in the literature that layer different opacities of composite (dentin, enamel, translucent) to mimic the multiple layers in a tooth. Personally, I have found this to be time consuming in a busy general practice and requires a larger assortment of composite material. However, a new composite material, SonicFill (Kerr), makes it possible to use a simpler technique involving a single shade of composite to restore most posterior teeth with excellent aesthetic results. This article describes a simplified technique to consistently restore posterior teeth with this new composite in a fast, easy and predictable manner. Case Presentation A patient presented for a routine hygiene visit and periodic oral examination. Upon clinical examination and probing, it was evident that tooth #3 had occlusal decay due to a stick with the explorer. Also, the radiograph exhibited some interproximal decay extending slightly past the dento-enamel junction. The patient complained of occasional discomfort when flossing and to cold. In order to educate the patient, we captured an image of this tooth on the intraoral camera (RF Systems Lab), and indicated the areas of concern on the flat screen monitor (Fig. 1). Using the DemoDent (DemoDent, Inc.) patient-education model we described what was occurring in the tooth (Fig. 2). "There are three layers in a tooth as illustrated in this model. The white is the enamel, the yellow is the dentin and the pink is the nerve. Your cavity is in between two teeth, where food and debris like to collect. When the cavity is in the enamel (white layer) you usually do not have any pain or sensitivity with it. In fact, by catching the cavity early, we can clean it out without any difficulty. Once the cavity has gone through the enamel and into the dentin (yellow layer), it spreads much more quickly. Patients might experience some sensitivity to hot, cold and sweets depending on how deep it has extended. Once the cavity gets into the nerve (pink layer), patients experience constant throbbing pain. We want to prevent this by stopping the cavity as soon as possible." After explaining the situation using the image on the screen and the anatomical model, I have found that patients seem to understand their dental condition better and are very eager to get started. The patient elected to have the restoration replaced with a bonded composite restoration using SonicFill (Kerr). Prior to administration of local anesthesia, the occlusal contacts were recorded to help guide placement of the composite material (to avoid areas of centric contacts). An appropriate shade (A1) was chosen and a rubber dam (Coltene Whaledent) placed for isolation (Fig. 3). After anesthetic was administered, a carbide bur Razor 557 (Axis) was used to remove the decay. As the preparations got deeper, any remaining decay was removed using a slow-speed handpiece and large round bur H8-RA (Axis). The preparations were extended to remove the caries in the palatal fissure region (Fig. 4). A sectional matrix band (V3-Ring, Triodent) was placed over the mesial margin of tooth #3 such that its position and shape would enable placement of a composite with an optimal mesial contour. For optimal contour, gingival seal and tooth separation a wedge was inserted between teeth #3 and #4. Using the V-3 forceps, the V-3 Ring was placed over the Wave-Wedge. It was important to burnish the band in the desired contact area against the adjacent tooth and make sure there was no spring back of the band. This would ensure an excellent contact. Once tooth #3 was isolated by the matrix band, it was dried and a sixth-generation primer/adhesive (OptiBond XTR, Kerr) was applied to all internal aspects of the preparation, including the cavosurface margins, for 20 seconds (Fig. 5). The primer was first gently agitated with a regular microbrush applicator tip (Microbrush) (Fig. 6). Because no rinsing of a separate etchant is required when using a self-etching technique, the collagen network was not subjected to the potential collapse associated with overdrying the dentin. A layer of the OptiBond XTR adhesive was placed, dried and then cured for 15 seconds with an LED curing light (Demi, Kerr). The material selected for the composite restoration was SonicFill (Kerr) which has a chameleon effect and can also be bulk filled, allowing it to blend in with the rest of the tooth surface. Utilizing the SonicFill Handpiece (Kerr) the material was dispensed into the preparation and bulk filled (Figs. 7 & 8). SonicFill's composite incorporates a highly filled proprietary resin with special modifiers that react to sonic energy. As sonic energy is applied through the handpiece, the modifiers cause the viscosity to drop (up to 87 percent), increasing the flowability of the composite and enabling quick placement and precise adaptation to the cavity walls. When the sonic energy is stopped, the composite returns to a more viscous, non-slumping state that is perfect for contouring. Increased levels of photo-initiators in the composite material allow a full 5mm depth of cure in 20 seconds. Studies indicate that SonicFill composite has a low 1.6 percent volumetric shrinkage and a high radiopacity (267 percent of Al). Fig. 1: Pre-operative condition showing cavityFig. 2: DemoDent patient education model illustrating conditionFig. 3: Tooth isolated with rubber damFig. 4: Removal of cariesFig. 5: OptiBond XTRFig. 6: Application of OptiBond XTR Fig. 7: Application of SonicFill. Fig. 8: Application of SonicFill. Fig. 9: Composite cured, finished and polished. Once tooth #3 was completely built up, cured, trimmed and polished, the sectional matrix was removed. The restoration was then shaped, trimmed and finished using carbides #7408 (Axis). The occlusion was checked and verified making sure there were no interferences in lateral and protrusive movements (Fig. 9).This case is a great example of how one can achieve an acceptable aesthetic result using a single shade of composite material that blends in with the surrounding tooth structure and bulk filled at the same time as opposed to the use of two or even three different shades with a layering technique. In a busy practice, use of a universal posterior bulk-filled composite like SonicFill (Kerr) not only saves operator time, but also allows for predictable and promising long-lasting options when preservation of tooth tissue is of paramount importance. Author’s Bio Dr. Ara Nazarian maintains a private practice in Troy, Michigan with an emphasis on comprehensive and restorative care. He is a diplomate in the International Congress of Oral Implantologists (ICOI). His articles have been published in many of today's popular dental publications. Dr. Nazarian is the director of the Reconstructive Dentistry Institute. He has conducted lectures and hands-on workshops on aesthetic materials and dental implants throughout the United States, Europe, New Zealand and Australia. He is also the creator of the DemoDent patient education model system. He can be reached at 248-457-0500 or at www.aranazariandds.com. Call Now San Francisco Dentist Request for appointment at: (415) 391 - 7751 450 Sutter street, Suite 1905 San Francisco, CA, 94108 http://malidds.com/

Welcome to San Francisco Dental Care

For more information, visit www.malidds.com/san-francisco-dentist.html