I am planning a series of small (7-10 attendees) hands-on implant seminars to be co-sponsored by my implant systems of choice, AstraTech and ITI/Straumann, and to introduce a new implant system Neoss. The first seminar entitled ‘Temporization and Abutment Selection for Restoring Implants’ will be held in conjunction with Tom Bates from AstraTech on September 19, 2007 at Black Angus on Friars Road. As of August 22 there was only one space left but we do plan to hold another similar seminar at the beginning of October. If you are interested in attending an upcoming seminar, or have any suggestions or requests for future topics please call Christine Haws, at 619 543-0905 or email her at dwrichards@adamember.net.

As most of you know I am very interested in using CT scan technology in planning the more difficult implant cases, particularly for mandibular placement. McCormack Dental Imaging Inc., is holding a seminar entitled ‘How Surgically Guided Implants Revolutionize Treatment Planning’ on September 7. For details please go to http://www.cdental.com/ or call our office for details.

Hereditary Gingival Fibromatosis

People born with hereditary gingival fibromatosis, a rare but benign condition in which gum tissue grows abnormally over the teeth, inherit an altered form of a gene called SOS1. This gene encodes a protein that is known to activate the ras pathway, one of the key growth signals in our cells. The hypothesis that the ras pathway could be involved in gingival overgrowth was recently tested by scientists at the NIH by expressing both the normal and mutant protein in primary gingival fibroblasts cells. They determined that an abnormal truncated version of the SO1 protein can reach the cell membrane where, without interacting with growth factor stimuli, can cause sustained activation of the ras/MAPK pathway. With this pathways stuck in the on position the gingival fibroblasts had an increased expression of cell cycle-regulatory proteins and gene-activating transcription factors resulting in unregulated growth.

As our understanding of the molecular mechanisms underlying normal and abnormal cell physiology grows the ability to target specific molecules to regulate and control oral diseases increases. As in this study the identification of a molecular cause for the abnormal proliferation of gingival fibroblasts suggests a more defined area to target when developing agents to halt gingival overgrowth in people with hereditary gingival fibromatosis. Jang et al., J. Biol Chem 2007 282: 20245

MMP-13 in Destructive Periodontal Disease

Matrix metalloproteinases (MMPs) are a family of enzymes that are responsible for the degradation of extracellular matrix components such as collagen, laminin and proteoglycans in both normal physiological and pathological processes. They are usually secreted as an inactive form requiring cleavage by extracellular proteinases for activation. MMP’s have been implicated in the connective tissue and bone loss that occurs in periodontitis, specifically MMP-13 (type 3 collagenase) which has been shown to play a role in the remodeling of periodontal ligament during tooth movement. Modified tetracyclines have been shown to inhibit the production of MMP-13 which may explain the effectiveness of low doses of doxycycline (20 mg twice/day) in decreasing periodontal disease activity.

The available evidence suggests that MMP-13 plays a significant role in both the initiation and progress of bone resorption. It is produced by periodontally affected human gingival fibroblasts and gingival sulcus epithelial cells. A recent study by Hernadez et al. reported that MMP-13 activity was significantly increased in gingival crevicular fluid (GCF) samples from patients with untreated chronic periodontitis.. The study included 21 patients with destructive periodontitis (periodontally affected sites presenting at least two sites with more than 2 mm clinical attachment loss). GCF samples were collected both from active and inactive sites (21 GCF samples, each) and the basal activity of MMP-13 was determined using an immunofluorescence assay. Expression of MMP-13 by gingival cells was measured with immunohistochemistry and in situ hybridization.

The results showed that MMP-13 was present in all of the GCF samples from both diseased and healthy sites. However, active disease sites had significantly higher MMP-13 activity levels than sites without disease and samples from sites with periodontal disease were found to have significantly higher proportions of the partially and fully activated forms of the enzyme.

The authors concluded that MMP-13is associated with periodontal disease and may play a role in the alveolar bone loss characteristic of chronic disease. Studies such as this that help to elucidate the pathological mechanisms of periodontal disease may lead to the development of new more effective treatments. Hernandez et al., J. Perio 2006, 77: 1863

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Evaluating health through Saliva

Simple, cheap diagnostic tests to screen for a variety of major diseases based on the analysis of saliva are within spitting distance of development.

Researchers at the Dental Research Institute at the University of California, Los have identified more than 1,500 proteins and about 3,000 mRNAs present in saliva. Saliva, like blood and urine, can be viewed as a repository of important information on illness and exposure to environmental substances.

This research has already uncovered indicators pointing the way toward diagnosing both oral cancer and an autoimmune illness called Sjogren's syndrome.

Oral cancer can be identified in saliva by screening for five specific proteins and four mRNAs that form a unique diagnostic signature in more than 90 percent of cases. Similarly, a small subset of proteins and mRNAs appears to serve as markers for Sjogren's syndrome.

Early detection of oral cancer via saliva testing could potentially help boost survival rates among the more than 31,000 Americans that the American Cancer Society estimates are currently diagnosed with some form of oral cancer each year. Approximately 7,000 men and women die from the disease annually.

An even larger patient pool now combats Sjogren's syndrome, a disorder in which white blood cells attack moisture-producing glands, causing dry eyes and dry mouth. The syndrome affects upwards of 4 million Americans.

Tests are being developed that use saliva to detect measles, mumps, rubella, hepatitis (A, B and C), breast cancer, Alzheimer's disease, and cystic fibrosis.

Disease testing using saliva is a means of bridging the gap between the medical and dental communities. A simple saliva assay that screens for a range of oral and systemic diseases could easily be performed in a dental office and any systemic findings shared with the patients’ physician. Clearly as evidence grows for an oral-body link feedback between a patient’s dentist and physician will be essential to a patients overall healthcare. Wong, D 2007. IADR New Orleans.

Periodontal disease in Women.

Three studies from recent issues of J. Periodontology suggest that periodontal diseases are a threat to women of all ages at least in part due to hormone fluctuations that occur at various stages of their lives.

The first study looked at 50 women between the ages of 20-35 to determine how current hormonal contraceptive medication influenced their periodontal health. The results showed that women who were taking contraceptive pills had more gingival bleeding on probing and deeper periodontal pockets than those who were not taking contraceptive pills. These data reinforce observations from a 1989 study that showed elevated levels of an oral bacterium associated with periodontal disease, bacteroides intermedus, in women using contraceptives and during the second trimester of pregnancy. Progesterone was found to compete for a binding site with an essential nutrient for the microbe thus promoting bacterial proliferation.

The second study examined 1256 post-menopausal women for a potential association between subgingival bacterial infection with eight species of oral bacteria, and bone loss in the oral cavity. The study found that sixty-two percent of the women enrolled in the study had a least one species of subgingival bacteria present and these women had more evidence of oral bone loss even after adjustment for age, smoking, and income. In addition, women who had a body mass index in the overweight range were much more likely to have oral bone loss associated with the presence of oral bacteria suggesting that weight could also be a confounding factor for periodontal disease. Oral bone loss in post-menopausal women has also been associated with osteoporosis.

The importance of monitoring the periodontal status of pregnant women especially during the third trimester is illustrated by data obtained from a study that measured the presence of periodontal bacteria in the amniotic cavity of pregnant women with a diagnosis of threatened premature labor. Twenty-six women with threatened premature labor were included in the study, eight diagnosed with gingivitis, twelve with chronic periodontitis and six with no disease. The bacterium P. gingivalis was detected in the amniotic cavity of eight enrollees all of whom demonstrated some degree of periodontal involvement.