Oral Health Group
Feature

Self learning, Self assessment

March 1, 2010
by Oral Health


The SLSA program is based on current, referenced literature and consists of 40 questions, answers, rationales are 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 tthe quiz will be forwarded to their respective provincial licensing authorities.

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Question 9

To decrease the risk of long term failure of a single implant for a first maxillary bicuspid, which of the following is/are applicable?.

1. Have forces directed in the long axis of the implant.

2. Keep loads small.

3. Have clearance between the implant tooth and the opposing arch.

4. Allow natural teeth only to participate in occlusal guidance.

A. 1, 2, 3

B. 1 and 3

C. 2 and 4

D. 4 only

E. All of the above.

Rationale

Implant failure can be broadly broken down into two – early and late. The former are usually associated with surgical procedures. Late failure is made manifest after osseointegration has occurred, for which occlusal overload is awarded the blame. A recent review provides guidelines for better management of implant bone prostheses to improve long term success. Kennedy Classes I, II and III are reviewed as well as the single tooth implant. Placement of an implant for the first maxillary bicuspid is often difficult because of lack of alveolar bone height and/or width. This requires occlusal loads to be small and directed in the long axis of the implant. Slight clearance is recommended between the implant’s occlusal surface and the opposing arch. Failure to leave occlusal clearance will subject the prosthesis to excessive load which the patient cannot feel because of a lack of periodontal ligament. In protrusive and lateral movements the occlusal surface of the implant should not be loaded and only natural teeth should participate in occlusal guidance.

Reference

1. Rilo, B., daSilva, J.L., Mora, M.J. et al. Guidelines for occlusion strategy in implant – borne prosthesis. A review. Int. Dent. J., 58 : 139 – 145, 2008.

Question 10

Orthodontic treatment results in improved periodontal health.

Gingival recession is greater after orthodontic therapy.

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

For some time argument has been made that orthodontic therapy makes for easier cleaning, therefore less soft tissue irritation and improved periodontal health. A recent review refutes this claim. It indicates an absence of reliable evidence to show positive effects on periodontal health following orthodontic treatment. Comparison of orthodontic treatment versus no treatment involved 1,670 participants, 821 treated and 849 untreated. Results were as follows:

– Pocket depth – 0.3 mm deeper in treated group.

– Gingivitis – similar numbers of bleeding sites in both groups.

– Alveolar bone loss – 0.13 mm greater in treated group.

– Gingival recession – 0.03 mm more gingival loss in treated group.

– Attachment loss – slight increase of loss in treated group.

Claims that orthodontic treatment results in improved periodontal health therefore cannot be supported.

Reference

1. Bollen, A.M., Cunha-Cruz, J., Bakko, D.W. et al The effects of orthodontic therapy on periodontal health. JADA 139 : 413 – 422, 2008.

Question 11

Potassium-containing compounds when deposited in quantity around nerves can interfere with the ability of the nerve to conduct pain stimuli.

A gel containing potassium nitrate, benzocaine and tetracaine in aqueous hydroxyethyl cellulose when placed over the teeth and gingiva for two minutes can reduce pain during deep scaling.

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

The discovery that depositing potassium-containing compounds, e.g. potassium nitrate (KNO3) around nerves in quantity can interfere with a nerve’s ability to initiate and conduct pain has led to new applications that have notably enhanced patient comfort. A gel, containing 35% KNO3, 20% benzocaine and 10% tetracaine in aqueous hydroxyethyl cellulose, when placed liberally over the teeth and gingiva for two minutes can effectively reduce discomfort associated with deep scaling. The topical anaesthetics in the gel anaesthetize the gingiva while the potassium anaesthetizes the teeth by entering into the orifices of the dentinal tubules ultimately preventing the nerves in the pulp from initiating and conducting pain. This process temporarily changes the membrane potential preventing stimuli to excite the nerve, thus providing anaesthesia of the tooth.

Potassium containing compounds, such as potassium-dimethylisosorbide is now being combined with glass ionomer cements, tooth whitening compounds, cavity liners and provisional cements to manage postoperative pain. A gel with this substance has also been developed for treating oral and/or dermatological ulcer pain.

Reference

1. Hodosh, M., Hodosh, S.H and Hodosh, A.J. KNO3/benzocaine/tetracaine gel use for maintenance visit pain control. General Dentistry July/Aug 312-315, 2007.

Question 12

In advising a parent about use of fluoride supplements, with which of the following would you agree?

1. Daily supplements prevent caries in the permanent dentition.

2. Daily use in the first 3 years is associated with fluorosis.

3. First year of life is the important period for fluorosis development.

4. Daily use is effective in prevention of caries in primary teeth.

A. 1, 2, 3

B. 1 and 3

C. 2 and 4

D. 4 only

E. All of the above.

Rationale

A recent review of some major studies is reported on the use of fluoride supplements, caries experience and fluorosis. There was evidence that fluoride tablets given to school children were effective in caries prevention (probably a topical action). The use of supplements during the first 3 years of life increased the risk of fluorosis and the first year of life was the most important period for development of fluorosis. Supplements were found to be limited in value where caries incidence is low and where fluoridated dentifrices are being used regularly. There is little evidence that supplements are of value in caries prevention of primary teeth. However, in permanent teeth the effects are very positive.

Reference

1. Ismali, A.I. and Hasson, H. Fluoride supplements, dental caries and fluorosis – a systematic review. JADA 139 : 1457 – 1468, 2008.

Answers to the February 2010 SLSA questions:

5. E

6. C

7. A

8. D