San Diego Prosthodontics Blog

Prosthodontics, Maxillofacial Prosthetics, Implant Restoration

Dr. Harold J Gulbransen

[Please see index of other blog topics at the bottom of this page.]

Precaution Against Denture Adhesives Containing Zinc

Wednesday, 30 March 2011 20:34

In February 2011, the U.S. Food and Drug Administration (FDA) sent a letter to all denture adhesive manufacturers, recommending removal of zinc from denture adhesive products and/or making significant label changes to warn consumers of potential dangers. This was in response to a number of scientific studies that suggest that zinc contained in some denture adhesives may contribute to zinc toxicity and neurologic disease.

Zinc is a mineral which is necessary to maintain your health. It is required to help regulate growth and metabolism in tissues where new cell development occurs, such as in the bone marrow and the intestinal lining. However, an excess amount of zinc, known as hyperzincemia, can contribute to copper deficiency, zinc toxicity and neurological damage. In the August 2008 publication of Neurology, researchers at the University of Texas Southwestern Medical Center in Dallas, linked use of large amounts of zinc containing denture adhesives to symptoms of neuropathy and zinc toxicity. It should be noted that patients in this study used a minimum of two tubes of denture adhesive weekly. Other researchers in the Department of Neurology at Vanderbilt University report in Neurotoxicology November 2009, patients experiencing progressive neurological symptoms following chronic overuse of zinc-containing denture adhesives.

The two primary manufacturers of zinc-containing denture adhesives in the U. S. are GlaxoSmithKline, which makes Super Poligrip, and Proctor & Gamble, which makes Fixodent. A small amount of zinc is used in these products to provide denture hold. Last year, GlaxoSmithKline agreed to reformulate Super Poligrip to remove zinc.

In 2009 the American College of Prosthodontists (ACP) formed a task force to establish evidence-based guidelines for the care and maintenance of complete dentures. At the conclusion of their study, they published a guideline for denture care in the Journal of Prosthodontics (Vol 20, Supplement1, February 2011)

Even with well-fitting dentures, they found that denture adhesives, when properly used, can improve the retention and stability of dentures and help seal out accumulation of food particles under the denture. However, the authors of the article caution against improper use of zinc-containing denture adhesives due to adverse systemic effects. So as a precautionary measure, they advise patients not to use zinc-containing denture adhesives.

The ACP further states that denture adhesives should be completely removed from the denture and the oral cavity on a daily basis. If increasing amounts of adhesives are required to achieve the same level of denture retention, patients should see their dentist or prosthodontist to evaluate the fit and stability of the dentures. Annual checkups with the dentist or prosthodontist are advised for denture wearers to achieve optimal fit and function of the dentures

References:

Denture cream: an unusual source of excess zinc, leading to hypocupremia and neurologic disease. Nations SP, Boyer PJ, Love LA et al. Neurology.2008; 71:639-643

Myelopolyneuropathy and pancytopenia due to copper deficiency and high zinc levels of unknown origin II: the denture cream is a primary source of excessive zinc. Hedera P, Peltier A, Fink JK, el al. Neurotoxicology 2009; 30:996-999

Evidence-Based Guidelines for the Care and Maintenance of Complete Dentures: A Publication of the American College of Prosthodontists. Felton D, Cooper L, et al. Journal of Prosthodontics Vol 20, Supplement 1, February 2011

Importance of Pre Radiation Dental Evaluations

Thursday, 03 March 2011 00:05

When the treatment for cancer of the head and neck requires radiation therapy, a thorough dental examination before treatment begins, by a dentist trained in this area, can help patients avoid many complications and achieve optimal results. To understand why it is imperative to have a pre radiation evaluation, it is first necessary to understand how radiation affects the oral cavity, salivary glands, teeth and bone.

Because it is very difficult to exclude the salivary glands from the radiation fields in the head and neck, radiation therapy may affect the salivary glands and the result is a change in the quantity and quality of the saliva. Saliva is important when discussing oral health because it both lubricates the mouth and balances the mouth’s acidity, thereby preventing tooth decay. Many patients experience dry mouth, called xerostomia.

Another more serious effect of radiation is to decrease the size and number of blood vessels in the area of radiation. This causes a decrease in the ability of irradiated tissue and bone to heal following surgery, injury or infection. Post radiation infections can be very serious with prolonged healing times, occasionally resulting in osteoradionecrosis.

For this reason, it is very important to thoroughly evaluate a patient’s dentition prior to radiation. To avoid future complications after radiation of the head and neck, any questionable teeth within the field of radiation may need to be extracted prior to initiation of radiotherapy. Extraction of teeth following radiotherapy could place the patient at risk for infections and osteoradionecrosis. In addition, during the pre radiation evaluation, custom topical fluoride trays are fabricated. These trays allow application of topical fluoride daily to help decrease the incidence of dental caries and infection. Patients should also be aware of the need for meticulous oral hygiene, as remaining teeth are usually at risk for dental caries secondary to their xerostomia, or lack of saliva. Long term maintenance includes three month visits to the family dentist or periodontist for cleaning and checkups. This is a lifelong commitment that patients need to make for optimal oral health.

In summary, the goal of the pre radiation dental evaluation is to avoid or minimize post radiation complications. By precluding many complications that could jeopardize treatment options and slow recovery, a thorough pre radiation dental examination is very important.

Dental Implants

Thursday, 17 February 2011 01:28

There are three main parts that make up a dental implant: the implant itself, the dental implant abutment and the dental prosthesis, which generally refers to the dental crown or dental bridgework that the implant supports. Dental implants, together with dental abutments, can be used to support single teeth, a group of teeth, or even all of the teeth.

Let’s discuss the three parts of a dental implant in more detail.

The dental implant fixture: The dental implant fixture is the portion of the implant that is embedded in and becomes anchored to the jawbone. This process is called osseointegration and provides stability and support for the dental prosthesis. The dental implant fixture is constructed out of titanium and is that portion of the dental implant that lies below the gum line.

The dental implant abutment: The dental implant abutment is a cylinder that is screwed on top of the dental implant fixture. The abutment aspect of an implant lies at or above the gum line. This stub portion is used to attach and support the crown, dental bridgework or denture that makes up the final restoration.

The dental prosthesis: The dental prosthesis refers to the dental crown, dental bridgework, or denture that the implant fixture supports. This can be either screwed or cemented in place, depending on the design.

Custom Dental Implant Abutments Using CAD-CAM Technology

Wednesday, 16 February 2011 19:12

The dental implant abutment transfers the load from the dental prosthesis to the titanium dental implant fixture. Over the years dentists have been frustrated by the lack of different abutment choices available for their patient’s implant restoration. Stock abutments were the only available choices. New advances in CAD-CAM procedures are now making it possible for dentists to create abutments that are customized for each of their individual patients needs.

CAD-CAM stands for Computer Aided Design and Computer Aided Manufacture. This technology allows the dentist and the laboratory to design very specific abutments that are custom manufactured to suit the individual needs of each patient. Using CAD-CAM technology, custom abutments are manufactured using scan data from the patient’s dental castings in conjunction with state of the art software and milling equipment.

Why is this so exciting? Dentists are now able to take into account individual differences in patient’s anatomy and implant restorations. In short, it customizes every patient’s treatment plan.

What is an Implant-Supported Denture?

Monday, 14 February 2011 21:32

An implant-supported denture is a type of overdenture that is supported by and attached to implants, while a conventional denture rests on the gums. An implant-supported denture is used when a person doesn’t have any teeth in the jaw, but has enough bone in the jaw to support implants. Special attachments are used to snap the denture onto the implants.

Although it is easy to remove an implant-supported denture from the mouth, some patients prefer to have fixed (permanent) crown and bridgework in their mouths which cannot be removed. Your prosthodontist will consider your specific needs and preferences when suggesting fixed or removable options.

It is important to understand the “behind the scenes” processing that is required for implant-supported dentures. Your prosthodontist has an in-depth knowledge of human anatomy and chewing function as well as an artistic talent to produce teeth that are both natural in appearance and esthetically pleasing. This also requires an extensive knowledge of quality dental materials.

At San Diego Prosthodontics, all removable prostheses, whether conventional or implant-supported dentures are fabricated in our in-house dental laboratory. This insures a high degree of quality control as well as timely delivery of prostheses to our patients.