The SLSA program is based on current, referenced literature and consists of 40 questions, answers, rationales and references. Answers appear in the following issue at the end of each quiz.
Dentists who complete the 15 question quiz in the November, 2009 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 17
For cementation of a provisional full crown restoration the luting agent of choice would be
A. calcium hydroxide (Dycal).
B. methylmethacrylate and acrylic resin (C& B Metabond).
C. self-etching dual-cure resin (Maxem).
D. resin-luting cement (Nexus 3).
Rationale
Provisional restorations can be cemented with calcium hydroxide (Dycal). It does not interfere with nor compromise the integrity of the permanent cement. It is placed only on the margins of an interim restoration prior to seating and not into the whole crown as this can lead to difficulty when trying to remove it.
C & B Metabond is the cement of choice for non-precious metals, such as resin bonded bridges and bonded posts in endodontically treated teeth. It bonds to enamel, dentin and metal. This cement is invaluable for patients who present with fractured porcelain and exposed metal on porcelain fused to metal restorations.
A cement that is proving to be a workhorse for most indirect restorations is Maxem. This self-etching, self-adhering cement is a dual-cure resin cement that is dispensed directly with an auto-mixing syringe. Once the restoration is seated, excess material can be light cured, allowing for easy clean up. It is indicated for all metal and ceramic inlays, onlays and full coverage restorations.
The resin-luting cement, Nexus 3, is ideal for cementing porcelain veneers as it is available in a number of shades and viscosities. This cement can be light-or dual-cured.
REFERENCE
1. Zarb, J. P. How can I limit the number of different cements available in my dental practice and still be able to address all prosthetic clinical situations? JCDA 73 : 697 -698, 2007.
QUESTION 18
Only a limited group of bacteria have the capacity to cause periodontitis.
Periodontal disease results when periodontal pathogens are present.
A. The first statement is true, the second is false.
B. The first statement is false, the second is true.
C. Both statements are true.
D. Both statements are false.
Rationale
According to the currently accepted theory of the development of periodontal disease, known as the specific plaque hypothesis, only a limited group of bacteria has the capacity to cause periodontitis. The occurrence of infection depends on there being a sufficient concentration of periodontal pathogens and these pathogens must express virulence factors. A person can harbour these pathogens without presenting any clinical symptoms. Symptoms appear only if the host’s defense mechanisms are no longer able to maintain homeostasis, and the host’s immune response modulates disease progression toward destruction.
Mechanical debridement of the dental biofilm and elimination of local irritating factors are the basis of periodontal therapy, but are not effective for all sites and forms of periodontal disease. The use of antibiotics is warranted for certain forms of the disease or for certain patients. Systemically administered antibiotics can reach microorganisms that are inaccessible to scaling instruments. However, in deciding whether to use curative systemic antibiotics, it is important to consider the potential benefits and adverse effects, including the development of resistant bacterial species.
REFERENCE
1. Bidault, P., Chandad, F. and Grenier, D. Risk of bacterial resistance associated with systemic antibiotic therapy in periodontology. JCDA 73 : 721 -725, 2007.
QUESTION 19
At the present time which of the following is the best treatment for sleep bruxism?.
A. Mandibular advancement device.
B. Clonidine therapy.
C. Occlusal splint.
D. Long term clonazepam therapy.
Rationale
It can be concluded that the following treatments can reduce sleep bruxism: a mandibular advancement device, clonidine therapy and an occlusal splint. However, the first two of these have been linked to problems which reduce their clinical effectiveness. A variety of adverse effects have been reported, including pain with the mandibular advancement device, suppression of rapid eye movement sleep with clonidine, as well as severe morning hypotension in people taking this drug. In addition, alternative medications such as benzodiazepines, and more specifically clonazepam, can engender pharmacologic dependence and drowsiness. Their use must therefore be limited to short periods for acute cases of bruxism. The occlusal splint is therefore the treatment of choice as it reduces grinding noise and protects the teeth from premature wear, without substantial adverse effect.
The pathophysiology of sleep bruxisim is not completely understood, but possible causes range from psychosocial factors (e. g. stress and anxiety) to excessive response to microarousals. Microarousals are defined as brief (3 to 15 sec.) periods of cortical activation during sleep, which are associated with increased activity of the sympathetic nervous system.
REFERENCE
1. Huynh, N., Manzini, C., Rompr, P. et al. Weighing the potential effectiveness of various treatments for sleep bruxism. JCDA 73 : 727 -730, 2007.
QUESTION 20
Which of the following is/are AIDS related malignancies?
1. Non-Hodgkin’s lymphoma.
2. Hodgkin’s lymphoma.
3. Basal cell carcinoma.
4. Kaposi’s Sarcoma.
A. 1, 2, 3
B. 1 and 3
C. 2 and 4
D. 4 only
E. All of the above.
Rationale
Advances in the management of HIV infection have resulted in significant changes in survival and in the prevalence and incidence of oral diseases in persons so infected. The increased risk to malignancy is related to immunosuppression and the activity of the HIV trans-activator of transcription protein, coviral infection and exposure to carcinogens. It is the dentist’s role to detect early changes in the mucosa that lead to a diagnosis of cancer and to maintain the patient’s oral and dental health.
People who are HIV-positive have more than a twofold increased risk of malignant disease, and an estimated 30% to 40% of HIV patients will develop a malignancy. AIDS related cancers include Kaposi’s sarcoma, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, basal cell carcinoma, cervical cancer, seminoma, leiomyoma and leiomyosarcoma. A risk of Hodgkin’s lymphoma, hepatocellular carcinoma and anogenital epithelial neoplasia has been associated with HIV, whereas data about the risk of testicular seminoma, multiple myeloma, melanoma and oral squamous cell carcinoma are limited.
REFERENCE
1. Epstein, J. Oral malignancies associated with HIV. JCDA 73 : 953 -956, 2008.
Answers to the April 2009 SLSA questions:
13. E
14. B
15. e
16. C
