Oral Health Group
Feature

Learning Assessment (June 01, 2000)

June 1, 2000
by Oral Health


The SLSA program is based on current, referenced literature and consists of 40 questions, answers, rationales and references.

Dentists who complete the 15 question quiz in the November, 2000 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.

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QUESTION 21

A maxillary central incisor was replanted after being out of the mouth for 45 minutes. A radiograph taken one year later is likely to show

A. root resorption

B. ankylosis

C. areas of normal periodontal ligament

D. All of the above

E. None of the above

Rationale:

Following replantation of an avulsed tooth, the terms “healing” and “repair” have been used interchangeably, but these are not equivalent. Healing implies that a replanted tooth does not exhibit any radiographic or clinical signs of inflammatory or replacement resorption. Teeth that exhibit repair may show evidence of resorption radiographically, but at the same time can also show areas with a normal periodontal ligament image.

It is accepted that avulsed teeth should be replanted immediately whenever possible. The most important factor for healing of the periodontal ligament is replacement of the tooth in less than 5 minutes. Dessication of the root surface periodontium is common. Although storage has been advocated in the patient’s own saliva or in milk, current research indicates that periodontal ligament healing is severely compromised when the extra-alveolar time period extends beyond ten minutes, regardless of the storage method. Patients should, therefore, be warned to expect root resorption or ankylosis in circumstances where the tooth is out of the socket for more than five minutes.

REFERENCE:

Layung, M.L., Barrett, E.J., Kenny, D.J. Interim storage of avulsed permanent teeth. J Can Dent Assoc 64:357-368, 1998.

QUESTION 22

A dental handpiece can be sterilized using a chemiclave.

A dental handpiece can be sterilized using a steam autoclave.

A. The first statement is true, the second is false.

B. The second statement is true, the first is false.

C. Both statements are true.

D. Both statements are false.

Rationale:

Cross-infection is defined as the transfer of pathogenic microorganisms from one person to another. The dentist must assume that every patient may be a carrier of infectious viruses or bacteria. It is the dentist’s responsibility to practise appropriate cross-infection control and to ensure that staff in the dental office are familiar with and also practise effective control measures. This must include appropriate sterilization methods for all dental instruments, including handpieces. Wiping with alcohol and immersing in a disinfecting solution cannot sterilize and thus are inadequate.

A study has demonstrated that handpieces subjected to ethylene oxide gas remained contaminated with test organisms compared to steam autoclave, which eliminated contaminants. A more recent study concluded that high-speed handpieces were not sterilized with chemiclave systems, but again were sterilized by steam autoclaves.

REFERENCES:

1.Kolstad, R.A. How well does the chemiclave sterilize handpieces? JADA 129:985-991, 1998.

2.Parker, H.H., Johnson, R.B. Effectiveness of ethylene oxide for sterilization of dental handpieces. J Dent 23:113-115, 1995.

QUESTION 23

An ankylosed tooth

1.gives no response to an electric pulp test.

2.loses its periodontal ligament.

3.continues its normal life cycle eruptive process.

4.becomes immobile.

A. 1, 2, 3

B. 1 and 3

C. 2 and 4

D. 4 only

E. All of the above

Rationale:

When a tooth becomes ankylosed, the protection of the periodontal ligament is lost, giving contact between alveolar bone and the tooth cementum. Osteoblasts then form a bony fusion. There is irregular replacement of cementum and dentin by bone repair. Thus, on percussion, a high-pitched sound transmits across this bony bridge to the jaw. With fixation, the tooth becomes immobile.

Since the pulp need not be affected, the electric pulp test may be at normal levels. Over time, however, the occlusal level of the tooth may be altered, as teeth on either side of the ankylosed tooth continue their life cycle eruptive process. This is particularly the case in ankylosis of primary molar teeth where they appear to be submerged.

REFERENCE:

Henderson, H.Z. Ankylosis of primary molars; a clinical, radiographic and histological study. J. Dent. Child 46:117-122, 1979.

QUESTION 24

Gingival inflammation is reduced by the use of triclosan with copolymer.

Supragingival irrigation is beneficial in the treatment of periodontitis.

A. The first statement is true, the second is false.

B. The second statement is true, the first is false.

C. Both statements are true.

D. Both statements are false.

Rationale:

Non-surgical periodontal therapy involves both mechanical and chemotherapeutic methods for control of plaques and in reducing inflammation. Benefits of scaling and root planing have been shown in many longitudinal studies in various age groups to include decreased gingival inflammation and probing depth, as well as the maintenance of clinical attachment levels. Significant reductions in gingival inflammation have been demonstrated with chlorhexidine, triclosan with copolymer or zinc citrate, essential oils, and stannous fluoride. Such agents do not give benefit in treatment of periodontitis, but may contribute to control of gingivitis when it exists with periodontitis.

Supragingival irrigation with these agents as adjunct therapy to tooth brushing has also been shown to reduce gingival inflammation. Supragingival irrigation has not been shown to give long term benefit for treatment of periodontitis.

REFERENCE:

1.Jeffcoat, M.K., McGuire, M., Newman, M.G. Evidence-based periodontal treatment. JADA 128:713-724, 1997.

2.Volpe, A.R., Petroni, M.E., DeVizio, W., et al. A review of plaque, gingivitis, calculus, and caries. Clinical efficacy studies with a fluoride dentifrice containing triclosan and PVM/MA copolymer. J Clin Dent 7. Supp. S1-S14, 1996.

Answers to May 2000 SLSA questions

17. E 18. E 19. B 20. A