Aesthetic Dentistry

[drmithila]

An interesting interview on the internet
Are posts really necessary in endodontically treated teeth?
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In this monthly feature, Dr. Gordon Christensen addresses the most frequently asked questions from Dental Economics® readers. If you would like to submit a question to Dr. Christensen, please send an email to info@pccdental.com.

Gordon J. Christensen, DDS, MSD, PhD
Q
I’m confused about the necessity of using posts in endodontically treated teeth. Some publications and speakers say that posts are always necessary, and others say they are never necessary. When, if ever, should posts be used, and what type of post should be used?
A
During my career to date, I have watched the use of posts and cores for endodontically treated teeth evolve from complicated, expensive, difficult to make, custom cast posts and cores, to metal prefabricated posts made from stainless steel, to titanium or titanium alloy, to today’s popular fiber-reinforced resin-based composite. In my opinion, there have been numerous misunderstandings about the need or lack of need for posts.
In my answer, I will discuss several factors that should be considered before making a decision about whether or not to place posts in endodontically treated teeth. My conclusions about posts are based not only on the research literature, which contains many excellent but sometimes confusing in-vitro studies on extracted teeth, but also my clinical experiences over many years as a practicing prosthodontist.
Factors to be considered in making the decision to use a post
Many have stated that the main reason for placing a post is to strengthen the connection between the coronal build-up material or remaining tooth structure to the root portion of the tooth. In my opinion, that is only partially true. Additionally, the following potentially negative or positive factors should be considered in the decision to use a post. All of these factors should be observed before making the decision:
• Quantity of remaining tooth structure
• Quality of remaining tooth structure
• Remaining adjacent teeth
• Occlusion
• Planned restoration to be placed on the tooth
Quantity of tooth structure remaining
Some teeth have most of the coronal tooth structure remaining after endodontic treatment, and others have very little tooth structure remaining. What is the significance of the amount of remaining tooth structure? For simplicity, I’ll divide the discussion of remaining tooth structure into several categories, and I’ll list them in decreasing order of clinical success:
All of the coronal tooth structure present except the endodontic access hole
If other negative factors (to be discussed later) are not present, such teeth usually do not require posts. After the endodontic procedure is completed, tooth colored resin-based composite should be bonded into the pulp chamber. These teeth usually continue to serve adequately as though they were vital teeth.
At least one-half of the coronal tooth structure remaining
This situation is one of the most common. Assuming the remaining coronal tooth structure does not have any of the negative characteristics discussed next, the occlusion is not heavy, and there are other teeth contiguous with the one being treated, this tooth may not need to have a post. The coronal tooth structure can be built up, usually with retentive resin-based composite build-up material, to provide additional retention for the subsequent restoration, and these teeth have excellent potential to serve uneventfully. However, if other negative factors are present, it is prudent to place a post.
Less than one-half of the coronal tooth structure remaining (Figs. 1-6)
It is my opinion, regardless of the other factors present, that it is still advisable to place a post or posts in such teeth. Endodontically treated teeth with less than one-half of the coronal tooth structure remaining have a reduced chance of long-term service, and patients should be so advised as the treatment plan is developed.
Fig. 1 — Premolar tooth with minimal tooth structure remaining requires a post and pins to ensure connection of the coronal build-up to the remaining root structure.
Fig. 2 — A fiber-reinforced resin-based composite post and two pure titanium pins (Filpins) have been placed in the premolar shown in Fig. 1 to ensure retention of the build-up material.
Fig. 3 — Radiograph from endodontist showing well done endodontic treatment, but minimal tooth structure remaining.
Fig. 4 — Tooth shown in Fig. 3 was built up with two fiber-reinforced resin-based composite posts and bonded composite.
Fig. 5 — Often, endodontically treated teeth with minimal tooth structure remaining, such as the second molar shown, can be built up adequately to provide long-term service.
Fig. 6 — Preoperative view of patient with gross caries in both maxillary and mandibular anterior teeth. Several of the teeth were treated endodontically and posts, build-ups, and tooth-colored crowns were placed on the teeth. Assuming adequate oral hygiene is practiced, teeth restored in such manner will serve for many years.
No tooth structure remaining coronal to the gingival tissue
There are clinical situations in which these teeth should be retained, including if the practitioner plans to extrude the tooth orthodontically. However, when considering the clinical success of dental root-form implants compared to questionable teeth, it is often better to extract the teeth and place implants. In the debatable event that a decision is made to restore such teeth, a post in single-rooted teeth or more than one post in multirooted teeth should be placed. Even with adequately placed posts present, the long-term success of such teeth is very questionable.
No tooth structure coronal to the bone
These teeth should usually be extracted. The only procedure, infrequently accomplished, that may allow teeth with long roots to be retained is orthodontic extrusion of the tooth. However, the cost of orthodontic extrusion and the time involved in waiting for the tooth to extrude and stabilize make the procedure questionable unless there is some major reason to retain the tooth.
Quality of remaining tooth structure
Assuming that there is a significant amount of coronal tooth structure remaining, the quality of the remaining tooth structure should be considered. Often, remaining tooth structure has discolored areas, slightly demineralized areas, cracks, undermined areas, or other negative characteristics. Removal of tooth structure with these characteristics allows a realistic and necessary appraisal of the amount of viable tooth structure remaining. After removing the affected areas, the same suggestions stated in the previous section on quantity of tooth structure remaining apply. Posts are often indicated.
Remaining adjacent teeth
If an endodontically treated tooth stands alone without adjacent teeth present, it will receive significantly more occlusal forces on it when compared to a tooth that has sound adjacent teeth. When restoring a tooth that has no or few surrounding teeth, it is appropriate to use a post or posts to augment the strength of the endodontically treated tooth, and to ensure that the remaining coronal tooth structure is strongly connected to the root portion.
Occlusion
One of the most important factors relative to the question of post placement in an endodontically treated tooth is the nature of the patient’s occlusion. Patients with bruxing or clenching habits place far more stress on teeth than those patients with normal occlusion. Usually, bruxers move their mandibles in left-right and forward-back movements, grinding off canine rise and incisal guidance. Enormous lateral stresses are placed on the teeth of these patients. Clenchers place forces in an apical direction with intense load and frequency. A logical decision is to place posts in bruxing and clenching patients.
Planned restoration to be placed on the tooth
An endodontically treated tooth planned to receive a single crown has minimal stress when compared to a tooth that is planned to be an abutment for a fixed prosthesis or an abutment for a removable partial denture. If an endodontically treated tooth is expected to have significant load placed on it in service, posts should be placed.
Our newest DVD, Posts, Cores and Build-Ups – Predictable and Strong, includes the best materials and techniques for placing adequate posts and cores. This one-hour video includes the best posts, bonding agents, cements for posts, build-up materials, and the most efficient and effective clinical techniques. Item # V1958 Posts, Cores and Build-Ups – Predictable and Strong is available online at http://www.pccdental.com or by calling PCC at 800-223-6569 .
In summary — YES, posts are often needed, and there are many clinical factors related to whether or not they should be used, in addition to just how much tooth structure is remaining. Clinical judgment is still critical in deciding whether or not to use posts.
Gordon Christensen, DDS, MSD, PhD, is a practicing prosthodontist in Provo, Utah. He is the founder and director of Practical Clinical Courses, an international continuing-education organization initiated in 1981 for dental professionals. Dr. Christensen is a cofounder (with his wife, Dr. Rella Christensen) and CEO of CLINICIANS REPORT (formerly Clinical Research Associates).

        

[drmithila]

More children are undergoing cosmetic dentistry procedures, such as having dental veneers and teeth whitening.

Pediatric dentists are increasingly being asked to place false teeth in a child’s mouth the replace broken or missing teeth, among many other procedures being performed to improve a child’s smile.

Based on most research, however, children should not have any cosmetic dental procedures performed on them. It’s ideal to wait until the permanent teeth have erupted and become stable in the mouth before performing cosmetic procedures. Only in emergency situations should a cosmetic dental procedure be performed on a child.

Tooth bleaching may not have a major adverse impact on the child, assuming there’s a less concentrated solution utilized. This will lower the amount of gum irritation.

Dental veneers, though, are much worse for children based on the removal of enamel required for the installation of many types of veneers.

All options must be discussed before deciding to perform a cosmetic dental procedure on a child. As always, maintaining good oral health by brushing, flossing and visiting the dentist regularly are the best ways to prevent your child from reaching this point.

        

[drmithila]

The International Association for Dental Research (IADR) has followed up a 2009 World Health Organization (WHO) report on the future of dental materials with two recent meetings designed to hash out an agenda for carrying out the WHO’s recommendations and related efforts to reduce the use of mercury and phase down dental amalgam.

The first meeting, hosted at King’s College of London on December 10-11, 2012, brought together representatives of the IADR, WHO, United Nations Environment Programme (UNEP), FDI World Dental Federation, and the International Federation of Dental Educators and Associations. Government agency representatives, dental materials researchers from leading manufacturers, and “sentinel centers for dental materials research” also were included.

The meeting was structured around the concept that dental restorative materials were lacking durability and resistance to fractures and wear. The respective role of each organization was recognized; for example, the WHO will focus on assisting governments in preventing oral disease, while IADR will facilitate the communication and application of research findings.

The FDI will work to put new research into practice and also has the difficult task of moving forward “a new paradigm shift” from restorative to a preventive/health promotion model. UNEP, meanwhile, has been crafting a legally binding treaty on mercury, in addition to working with governments in the realm of environmental protection.

New materials needed

At the London meeting, the participating stakeholders discussed a range of topics, including identifying performance gaps in the current armamentarium of dental restorative materials, promising areas of dental materials research, and developing a prioritized agenda and global action plan in dental materials research “to address individual and population-level health with environmental compatibility and economic feasibility,” the IADR noted in a summary of the meeting.

The IADR presented information about the risks posed by restorative materials currently in use. “Safety is defined as freedom from unacceptable risks,” the organization explained. “In terms of clinical risk, all restorative materials can be described as safe with less than 0.1% chance of reactions, which are local, compared to 12% for cosmetics.”

There is “little apparent systemic toxicity” in dental restorative materials currently in use, the IADR added, although more data about bisphenol A (BPA) is needed because research has shown that it may be harmful. In fact, environmental concerns about mercury outweighed concerns about toxicity at the London meeting; according to the IADR, amalgam accounts for 2% of anthropogenic mercury emissions to air and roughly 8% of mercury demand or consumption in processes and products. The IADR also pointed to amalgam’s superior longevity compared with resin-based composites and glass ionomers.

The properties of an ideal restorative “biologic biomaterial” were specifically outlined during the meeting. It “would seal the interface between the tooth and the restoration, be adhesive to the tooth with little or no shrinkage, interact favorably with carious dentin and enamel, be clinically easy to use in a variety of settings, and be fracture- and wear-resistant and repairable.” Aesthetics, cost-effectiveness, and zero toxicity were among the items added to an ambitious set of features.

The involved organizations will wait patiently for that material to arrive. “All were committed to the goal of the workshop to develop a research agenda for better dental materials so that dental amalgam could be phased down,” the IADR wrote.

Global mercury treaty unveiled

Interestingly, some amalgam supporters and antiamalgam groups both approve of the direction and pace of change under way. At a UN forum last week in Geneva, UNEP unveiled a draft treaty — to be known as the Minamata Convention on Mercury — that includes a section specific to dental amalgam.

The treaty, which has been four years in negotiation and will be open for signature at a special meeting in Japan in October, addresses the direct mining of mercury, export and import of the metal, and safe storage of waste mercury.

The treaty also pushes for the phase down of dental amalgam, such as incentivizing amalgam alternatives through insurance, focusing on these alternatives in dental schools, restricting encapsulated dental amalgam, focusing research on improving alternatives, and promoting dental caries prevention. In addition, the treaty specifies a best practice approach to minimizing the release of waste dental amalgam, currently typified by the use of amalgam separators in dental practices that permit the capture, separation, and eventual recycling of mercury.

The UNEP proposal elicited a positive reaction from the ADA.

“The ADA is gratified that the treaty conditions pertaining to dental amalgam protect this important treatment option without restrictions for our patients while balancing the need to protect the environment,” the association stated in a press release. “The ADA is also delighted that the proposed treaty recognizes the need for national programs to prevent oral disease and calls for more research into developing new treatment options. Long term, it is critically important to raise global awareness of the importance of oral health to overall health, including how to prevent dental diseases. Doing so decreases the need for all cavity-filling and other restorative materials, including dental amalgam.”

The Mercury Policy Project, an antiamalgam group that had representatives at the Geneva meeting, was similarly satisfied with the draft treaty.

“This is the beginning of the end of dental amalgam globally,” Michael T. Bender, director of the Mercury Policy Project, stated in a press release. “We applaud the leadership role the U.S. played in jump-starting support for a phase down in 2011, along with the concrete steps of the Nordic countries, Switzerland, and Japan took in phasing out dental amalgam.

        

[Drsumitra]

Cosmetic veneers offer a superior way to restore the look of chipped, broken, or discolored teeth. Made of either porcelain or acrylic, veneers are thin shells that are bonded to the front of teeth, effectively changing a tooth’s width, length, shape, and color. Veneers are a great solution for patients who want to cover stable, healthy teeth.

There are several reasons to choose veneers over other cosmetic dental procedures, such as dental crowns or braces. Veneers are custom-designed shells made of materials that mimic the look of real teeth. When applied to the surface of stable teeth, veneers can correct the look of worn tooth enamel, uneven tooth alignment or spacing, and chips or cracks.

Veneers are also a great option for patients who want to improve the look of teeth that are discolored and cannot be whitened with bleach teeth whiteners. Porcelain veneers mimic the luster and look of real teeth, and can make teeth look whiter and brighter while resisting future stains.

How Are Cosmetic Veneers Applied?
If you are considering cosmetic veneers, consult with your dentist to determine if you are a good candidate. Your dentist will consult with you about your options, expectations, and the process involved in creating, applying, and maintaining your customized veneers. It could take up to three more visits to complete the process.

During your first appointment, your dentist will take x-rays and possibly make a model or impression of your mouth and teeth. The model is sent to a dental laboratory where technicians will create your customized veneers within 1 to 2 weeks.

The next appointment involves bonding the veneers to the surface of your teeth. To prepare your tooth for a veneer, your dentist will first deep clean and polish your teeth. The teeth must then be etched, which involves removing about ½ mm of enamel from the tooth surface, about the thickness of the veneer. Talk to your dentist about the use of local anesthetics or sedation dentistry for this step of the procedure if you are concerned about comfort. Your dentist will most likely need repeatedly remove and trim the veneer to achieve the right shape and fit. The color of the veneer is adjusted with the bonding cement, which is then activated with a special light beam to harden the cement and bond the veneer quickly. Your final appointment will be a follow-up consultation so that your dentist can ensure that your gums are handling the veneers without any irritation and to evaluate the veneer’s placement.

If you want to improve the look of chipped, broken, discolored, or misaligned teeth, cosmetic veneers could be the best solution for you.

 

        

[drmithila]

By Laird Harrison
The approach contradicts what most dentists learned in dental school. And it can add another step to the process of placing an indirect restoration. But a growing chorus of researchers, taking their lead from Pascal Magne, D.M.D., Ph.D., says it’s well worthwhile to seal dentin before placing a temporary.

The notion goes back at least to 1992 when David Pashley, D.M.D., Ph.D., a Medical College of Georgia professor, proposed sealing dentin immediately after preparation for a crown.

Now evidence is mounting for immediate dentin sealing (IDS), not only for crowns but also for inlays, onlays, and veneers. At least one adhesive company — Bisco — has taken the approach into consideration in designing its latest products. And IDS is being debated at widely attended symposia on restoration techniques, including the 2008 ADA meeting in San Antonio.

“I meet people all the time who are enthusiasts,” Dr. Magne told DrBicuspid.com. Dr. Magne, a University of Southern California associate professor, has extensively researched the method and become its leading proponent. “It seems like it’s obvious that it’s a useful procedure. There’s nothing to lose.”

But at the recent ADA meeting, Jeff Brucia, D.D.S., co-director of the Foundation for Advanced Continuing Education (FACE), suggested that a careful variation of the conventional technique might be more practical than IDS.

In his latest paper (Journal of Prosthetic Dentistry, September 2007, Vol. 98:3, pp. 166-174), Dr. Magne and his colleagues prepared 30 extracted human molars and immediately bonded their dentin: 15 with OptiBond FL (Kerr Dental) and 15 with SE Bond (Kuraray). They then restored the teeth with Tempfil Inlays (Kerr) and soaked them in saline solution for 2, 7, or 12 weeks before removing the temporaries, cleaning and sandblasting them, and applying more adhesive to restore them with Z100 (3M ESPE).

For comparison purposes, they placed Tempfil Inlays on 10 molars without bonding the dentin first, and soaked these in saline solution for two weeks before using either OptiBond FL or SE Bond to attach the Z100.

They found that the microtensile bond strength of the permanent restorations on the IDS teeth was between 5 and 33 times stronger than it was on the conventionally restored teeth.

One reason IDS is stronger is that dentin bonds best to composite when the dentin is freshly cut, Dr. Magne said. Provisional cement, saliva, and bacteria can all contaminate the dentin and weaken the seal.

Also, curing the adhesive before placing the restoration may result in a stronger bond because the cured adhesive keeps collagen fibers from collapsing under pressure when the restoration is put in place.

Another reason the bond may be stronger is that the copolymerization continues for several days before it takes on an occlusal load.

IDS also results in less sensitivity when the temporary is removed and the permanent restoration placed; in fact, with IDS no anesthesia is required during this step (unless needed for the rubber dam), Dr. Magne said.

Finally, if you seal the dentin before making the impression, the impression includes the contours of the adhesive.

He lays out complete instructions for his approach in the Journal of Esthetic and Restorative Dentistry (May 2005, Vol. 17:3, pp. 144-155).

The technique is becoming so popular that Bisco’s instructions for All-Bond 3 — released in February 2007 — explain how to use it prior to impression making for crowns. In addition, the company is planning to launch a new product, Pro-V Coat, which can be used to keep temporaries from bonding to the adhesive used in IDS.

(Dr. Magne uses OptiBond FL as the adhesive and applies a layer of glycerin jelly to isolate the temporary.)

Speaking at an ADA seminar on new restorative techniques, Dr. Brucia agreed that it’s important to seal the dentin right after preparing it. He said he’d tested the IDS technique described by Dr. Magne and found it “excellent.”

But he also noted that many dentists are likely to make mistakes in applying it. For example, he argued that it’s difficult to bond to the cured adhesive unless the surface is roughened by proper sandblasting. He thinks many dentists will omit this step or will use aluminum oxide instead of CoJet (3M ESPE). Or, he said, many dentists will use unfilled adhesive, which isn’t thick enough to stand up to such sandblasting.

Because of the difficulty of the technique, Dr. Brucia, “It’s not accepted within the dental industry.”

So he proposed an alternative. “Pascal will tell you that the only time you can get excellent bond strength to dentin is the day that you prepped it,” Dr. Brucia said. “That’s not exactly true. If you can keep that tooth clean and refreshen the dentin at cementation, you will be able to produce that exact bond.”

The key, he argued, is to find a cement that bonds to the tooth rather than to the temporary restoration. This will seal the tooth until it’s time to place the permanent restoration. Dr. Brucia uses Durelon (3M ESPE). He removes it with an ultrasonic scaler, a process he said takes him only about 20 seconds.

“I disagree, of course,” said Dr. Magne, when asked about this approach. “It would be a dream if the cement would do everything. But you will not get the effect of desensitizing the tooth once and for all.”

Dr. Magne usually doesn’t need to anesthetize his patients for try-in procedures or when placing the permanent restoration, while Dr. Brucia does.

Dr. Magne also argued that curing the adhesive just before placing the permanent restoration results in a layer that changes the contours of the surface being restored. And leaving the adhesive uncured when placing the final restoration results in a weaker bond.

In the end, though, both experts agree on one important principle: seal your dentin when you place the temporary.

        

[chith1890]

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[CaseyWooten]

Thanks for this useful post.

        

[Author]

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