Self Learning Assessment 2006 (February 01, 2006)

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, 2006 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.


As a clinician, which of the following would you consider the most reliable for early detection of high-risk primary oral pre-malignant lesions?

A. Biopsy

B. Colour and texture

C. Cytology from a smear

D. Toluidine blue staining


Early detection of oral premalignant lesions (OPLs) is of absolute importance in improving the prognosis for patients with squamous cell carcinoma. The clinician has to be able to differentiate between the OPL and other inflammatory and reactive lesions which are prevalent in the mouth. Dysplasia may predict high grade lesions but it has limits in predicting lesions with minimal or no dysplasia which make up the majority of OPLs. Toluidine blue retention has been shown to identify high-risk molecular clones even in lesions with little or no dysplasia. A recent study examined 162 patients in the Oral Dysplasia Clinic at British Columbia Cancer Agency between 1996 and 2004. Criteria for eligibility eliminated 62 patients leaving a study group of 100 of which 78% were Caucasian and the rest Asian. Lesions were assessed for toluidine blue status using 1% toluidine blue (Ora Test) and de-staining with 1% acetic acid. Data of the study supported the value of toluidine blue as a tool for clinical diagnosis of high-risk primary OPLs. It not only detected virtually all (16 out of 17 cases) high grade dysplasias but also preferentially stained OPLs with minimal or no dysplasia but with high-risk attributes.

Biopsy will only detect established carcinoma or provide negative data but will not give prediction of change to malignancy. Similar comment can be made regarding examination of colour and texture of a lesion. Cytology from the surface of a suspicious area will provide some data but will not predict outcome. BIOPSY, however, must be used in confirming that a lesion is malignant.


1.Zang, L., Williams, M., Poh, C.F., et al. Toluidine blue staining identifies high-risk primary oral premalignant lesions with poor outcome. Cancer Res. 65:8017-8021. 2005.


Following periodontal therapy, smoking

1. decreases the response of the smoker’s microbiota to therapy.

2. compromises soft tissue maturation.

3. compromises mineralization of hard tissue.

4. increases the prevalence of Porphyromonas gingivalis.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4


A strong association exists between tobacco smoking and an increased incidence and severity of periodontitis, coupled with a poorer treatment response. Smoking compromises both soft tissue maturation and mineralization of hard tissues. There is a decreased response of a smoker’s microflora to therapy, which may partly explain the often unfavourable treatment results in smokers.

A study was conducted on patients with periodontal disease to determine the effect of smoking on treatment outcomes. Patients were smokers and non-smokers. Treatment groups included

* initial therapy only, initial therapy and antibiotics

* initial therapy followed by surgery

* initial therapy plus antibiotics and surgery.

All clinical parameters improved in both smokers and non-smokers following treatment, but non-smokers showed significantly more gain of clinical attachment after therapy. Although, after treatment, smokers and non-smokers had pocket depth differences, they were not statistically significant. Analysis of the presence and proportion of specific target organisms in periodontal pockets before and after therapy was carried out. No differences were reported in the prevalence of the target bacteria between smokers and non-smokers before treatment. In non-smokers, the prevalence of target bacteria decreased significantly after treatment, but only the prevalence of Porphyromonas gingivalis decreased in smokers after therapy, while other target organisms remained. In a study where periodontal tissues were examined after being on a quit-smoking program, patients showed a two-fold increase in bleeding on probing. It is thought that smoking masks the signs and symptoms of the inflammatory process. In dealing with such patients, the dentist should institute a treatment program of hygiene and advise the patient that a possible increase in gingival bleeding may occur. Dental health professionals should explain the risk of smoking to both oral and systemic health and encourage and facilitate smoking cessation.


1.Van der Velden, U. Varoufaki, A., Hutter, J.W., et al. Effect of smoking and periodontal treatment on the subgingival microflora. J Clin Periodontol. 30:603-610. 2003.

2.Nair, P., Sutherland, G., Palmer, R.M., et al. Gingival bleeding on probing increases after quitting smoking, J Clin Periodontol. 30:435-437. 2003.


Which of the following are risk indicators for posterior tooth fracture?

1. Presence of a Class V restoration

2. Age

3. Fracture lines in the enamel

4. Clenching habit

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4


Using 39 potential risk indicators 200 patients with tooth fractures were compared to 252 patients without fractures. Clinical characteristics of individual teeth were identified and risk indicators in patients recorded. Neither patient behaviour such as clenching habit, grinding, biting hard objects, nor occlusal characteristics such as canine guidance, cusp anatomy or wear patterns were identified as predictors of tooth fracture risk. Amongst posterior teeth with restorations, two major factors of risk were identified, the presence of a fracture line in tooth enamel and the relative proportional volume of the natural tooth occupied by the restoration. If a Class V restoration was also in the tooth, there was an increased risk of fracture since it further decreased the tooth volume.

Other factors related to fracture risk were: the restoration size and the isthmus width and depth. Tooth age was also significant in that a ten-year increase in the patient’s age increased the fracture odds by 70% so that a 60-year-old had a 70% greater fracture risk than a 50-year-old.


Bader, J.D., Shugars, D.A., Martin, J.A. Risk indicators for posterior tooth fracture. JADA. 135:883-892, 2004.


Which of the following would comply with the present-day guidelines for infection control in your office?

1. Expose the handpiece to ethylene oxide for 1 minute.

2. Discharge water and air from the handpiece for 20-30 seconds after use.

3. Place ultrasonic scalers in a liquid chemical sterilant.

4. Clean and heat sterilize the handpiece between patients.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4


For infection control in oral care settings, an updated set of guidelines has recently been formulated. These cover a wide range of topics: education and protection of personnel, prevention of transmission of blood-borne pathogens, sterilization and disinfection of patient care items. Dental handpieces and other devices attached to air and water lines are given special attention, along with saliva ejectors, radiographic materials and disposable devices.

Any item that enters the patient’s mouth, e.g., handpieces, ultrasonic scalers and air/water syringes that are connected to the water system, must have a discharge of wa
ter and air through the device for a minimum of 20 seconds after each patient. Following this, the handpieces and other devices above are removed, cleaned, and heat-sterilized (autoclaved). Do not surface-disinfect, do not use liquid chemical sterilants, nor ethylene oxide on handpieces and other intraoral instruments.

Patients should be advised not to close their lips tightly around the tip of the saliva ejector to evacuate oral fluids because of increased potential for reverse flow.

Extracted teeth should be disposed of as regulated medical waste unless returned to the patient. Biopsy specimens must be placed in sturdy leakproof containers and labelled with the biopsy hazard symbol.


Kohn, W.G., Harte, J.A., Malvitz, D.M., et al. Guidelines for infection control in dental health care settings. JADA. 135:33-47, 2004.

Answers to the January 2006 SLSA Questions

1. A

2. E

3. A

4. C