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Learning Assessment (March 01, 2001)

March 1, 2001
by Oral Health


The SLSA program is based on current, referenced literature and consists of 40 questions, answers, rationales and references. Answers appear at the end of each quiz.

Dentists who complete the 15 question quiz in the November, 2001 issue of Oral Health may be eligible to receive continuing education points. The names and license numbers of all who complete the quiz will be forwarded to their respective provincial licensing authorities.

QUESTION 9

Only a small number of adults seek orthodontic therapy because they

1. are ignorant that such treatment can be effective at their age.

2. fear pain and discomfort.

3. are concerned about social acceptance of wearing an appliance.

4. consider the teeth will take too long to move.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4

Rationale

Studies have shown that 65-75% of adults have some form of malocclusion which results in poor aesthetics, reduced masticatory function, occlusal trauma, and predisposition both to caries and periodontal disease.

Orthodontic tooth movement can be impeded by certain drugs used primarily by adults, especially prostaglandin inhibitors such as indomethacin prescribed for arthritis. Inhibitors of bone resorption used to treat osteoporosis, e.g., alendronate, can also impede tooth movement. Localized bone loss as a result of periodontal disease does not preclude orthodontic care, but it is essential that the inflammatory disease is controlled before treatment. Brackets and bands make oral hygiene difficult. Bonded brackets rather than bands are indicated for adults. In addition, because of the higher crown height of adult teeth, there is less plaque accumulation and oral hygiene is easier.

Although there are age-related biochemical changes in the adult such as decreased alveolar vascularity, altered bone mineralization and increased collagen rigidity, these have not impeded orthodontic care. Indeed, studies have shown no difference in the duration of treatment when similar adult and adolescent problems are dealt with.

Most adults after treatment mention some discomfort, but not pain. The concern regarding social acceptance of appliance-wearing is no longer a factor as smaller and less obtrusive brackets have been designed, and more adults are seeking such care.

General practitioners should be aware of these factors for the benefit of their patients.

REFERENCE

Buttke, T.M, Proffit, W.R. Referring adult patients for orthodontic treatment. JADA 130:73-79, 1999.

QUESTION 10

In a patient taking blockers for hypertension, an injection of local anaesthetic with a vasoconstrictor (epinephrine) into the periodontal ligament will

1. provide rapid analgesia of the tooth.

2. cause ischaemia of the pulp and surrounding tissues.

3. increase the duration of the pulpal and soft tissue analgesia.

4. reduce post-operative pulpal pain.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4

Rationale

A recent study involving patients receiving blockers compared to those without in which various reactions to local anaesthetic with epinephrine were recorded, failed to show any changes in blood pressure or pulse rate between groups. However, there was a marked increase in the duration time of pulpal and soft tissue analgesia in those with blockers. No difference was reported in either group in the duration of anaesthesia when local anaesthetic without epinephrine was used.

It is established that post-operative pulpitis results from the release of a neuropeptide called substance P from sensory nerve endings. When an injection of local anaesthetic is made into the periodontal ligament, there is a considerable degree of vasoconstriction induced by the epinephrine. This leads to an almost ischemic condition of the pulp and during tooth preparation the neuropeptides are accumulated instead of being washed out from the pulp tissue. Pulpal damage occurs which leads to post-operative pulpitis. Clinical techniques must all aim at reducing the neuropeptide release. Therefore, kindness to tissues is necessary. Handpieces should provide coolant circumferentially to the tooth and use of sharp burs, along with small incremental reduction of dentin, are essential. These actions will control heat build-up and reduce the amount of neuropeptide release. Following injection into the periodontal ligament, the rapid onset of analgesia is related in part to the increased fluid content of the ligament-a form of pressure anaesthesia.

REFERENCES

Zhang, C., Banting, D.W., Gelb, A.W., et al. Effect of -adrenoreceptor blockade with nadolol on the duration of local anaesthesia. JADA 130:1773-1780. 1999.

Kim, S., Dorscher-Kim, J., Liu, M.T., et al. Biphasic pulp blood response to substance P in the dog as measured with radiolabelled microsphere injection method. Arch Oral Biol 33:305-309. 1988.

QUESTION 11

Which of the following chemotherapeutic agents, when used locally for the treatment of periodontitis has/have the risk of producing resistant organisms?

1. Actisite.3. Elyzol.

2. Atridox.4. Periochip.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4

Rationale:

A recent symposium examined the delivery of local chemotherapeutic agents in the management of periodontal disease. Actisite is a trade name for tetracycline containing fibres which are inserted into the periodontal pocket. With a single application tetracycline is released over time in effective concentrations. However, since it is an antibiotic, resistant strains of microorganisms may occur.

Atridox introduces a gel which will deliver doxycycline to the pocket. The gel releases the antibiotic over time and is biodegradable. Risk of antibiotic resistance again exists.

Elyzol is also in gel form and delivers local concentrations of metronidazole. It has the advantage of activity against anaerobic organisms. Two applications are needed one week apart and, although effective, this treatment has the disadvantage of creating resistant bacteria.

The Periochip relies on release over time of chlorhexidine in a local site. As it is not an antibiotic, resistant strains of microorganisms will not develop. It has the benefit of easy application. It has recently been shown not only to be an effective treatment, but also to be highly cost-effective. In disease management, it may be used as an adjunct to scaling and root planing, or in maintenance therapy of deep pockets, thereby avoiding a surgical procedure. Such a regimen calls for placing the Periochip in pockets over 5 mm every three months.

REFERENCES:

Finkelman, R.D., Williams, R.C. Local delivery of chemotherapeutic agents in periodontal therapy: Has it arrived? J Clin Periodontol 25:943-946, 1998.

De Lissovoy, G., Rentz, A.M., Dukes, E.M., et al. The cost-effectiveness of a new chlorhexidine delivery system in the treatment of adult periodontitis. JADA 130:855-862, 1999.

QUESTION 12

Which of the following factors increase(s) the risk of root caries?

1. Aging.

2. High plaque index.

3. High counts of lactobacilli and Streptococci mutans.

4. Low exposure to fluoride.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4

Rationale

Root caries is a localized destruction of dentin and cementum, which is caused by microorganisms. The lesions can be found at the cemento-enamel junction or are confined entirely to the exposed root surface. As with coronal caries, the three main factors of host, microflora, and diet have to be present and interact. However, the following increase root caries risk: newly exposed root surfaces, low salivary secretion rate, high counts of lactobacilli and Streptococci mutans, frequent intake of fermentable carbohydrates, high plaque index and low exposure to fluorides.

Salivary secretion decreases with advancing age, and many drugs prescribed for the elderly to manage medical problems cause xerostomia. As gingival recession in the elderly results in more exposed root surfaces, poor oral hygiene in this older population can result in increased root caries.

A recent study has demonstrated that, in the elderly, coronal caries is associated with higher levels of S. mutans, whereas lactobacilli are found in higher numbers in root surface caries. Several studies have shown that the incidence rate of caries, both coronal and root forms, increases with age. For example, root caries incidence in 45-65 year-olds is 32%, 65 to 75 years 43%, and 75+ years 47.8%

REFERENCES

Loesche, W.J., Taylor, G.W., Dominguez, L.D. et al. Factors which are associated with dental decay in the older individual. Gerontology 16:37-46, 1999.

Ettinger, R.L., Mulligan, R. The future of dental care for the elderly population. J Calif Dent Assoc 27:687-692, 1999.

Answers for February 2001 SLSA questions:

5. A 6. C 7. A 8. E


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