Oral Health Group
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2004 Self Learning Assessment (February 01, 2004)

February 1, 2004
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, 2004 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 5

Management of early caries is dependent upon the

1. pH of saliva.

2. frequency of the cariogenic challenge.

3. mineral ion concentration of the saliva.

4. availability of mineral ions in the saliva.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4

Rationale

Tooth enamel is under cariogenic and demineralization attack constantly. The oral environment is capable of removing mineral substance from the teeth, which, if unchecked, will allow cavitation to develop. Remineralization is a natural phenomenon and, under appropriate conditions, deposition of mineral will occur, reversing the carious process. Factors determining the correct direction of remineralization are pH, the concentration of mineral ions and their availability in the saliva, as well as the severity and frequency of the cariogenic challenges.

Amorphous calcium phosphate, because of its solubility, can enhance the calcium and phosphate ions in saliva. The simultaneous application of fluoride ions with high concentrations of calcium and phosphate ions improves remineralization. This has resulted in the development of a dual phase system toothpaste which isolates the calcium portion of the paste from the phosphate and fluoride portions until the time of application, when the ions of all three are released in the saliva to support remineralization.

A study involving 2,506 children examined the use of this bi-chambered dentifrice in the management of dental caries in 5-17 year olds. One group of children was given the test dentifrice in which one chamber contained 0.243 per cent sodium fluoride in a silica base and the other chamber dicalcium phosphate dihydrate. The other group received 0.243 per cent sodium fluoride in the silica base only. Using DMFS scoring, the mean caries increments after the first year failed to show significance between the two groups. However, after two years, the figures were statistically significant and represented a 14.38 per cent decrease in the overall caries score.

REFERENCES

1.Boneta, A.E., Neeswith, A., Mankodi, S. et al. The enhanced anticaries efficacy of a sodium fluoride and dicalcium phosphate dihydrate dentifrice in a dual chambered tube: a two-year caries clinical study on children in the United States of America. Am J Dent 14:13A-16A. 2001.

2.Oral Care Report, Vol 9 No.1 Ed. C.W. Douglass, 1999.

QUESTION 6

After placement of implants to support a fixed partial prosthesis, which of the following will influence bone loss around the implants in the first year of loading?

1. The sex of the patient.

2. The age of the patient.

3. The jaw receiving the implant.

4. The design of the prosthesis.

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4

Rationale

A recent Canadian study over a twelve-year period examined the bone level changes seen around implants of the Brnemark system. The implants were used to support fixed partial prostheses and clinical bone measurement was determined by radiography.

Implants placed in men showed greater bone loss in the first year of loading. No difference between the sexes was seen for mean annual bone loss thereafter. Implants in younger subjects lost more bone over the first year of loading than those placed in older subjects. In part, this may be due to the likelihood of placement in alveolar bone rather than basal bone. Comparing jaws, there was more bone loss around implants in the mandible than the maxilla in the first year of loading.

Implants supporting distal extension prostheses had significantly more bone loss in the first year of loading compared to those supporting a prosthesis bounded by natural teeth.

Since challenges exist regarding the reliability of radiographic measurement of bone levels around implants, a laboratory study was carried out on cadavers. The study compared various radiographic methods and concluded that compared to the actual measurement of bone on the cadavers, standard radiographic techniques provided acceptable accuracy.

REFERENCES

1.Wyatt, CCL, Zarb, G.A. Bone level changes proximal to oral implants supporting fixed partial prostheses. Clin Oral Impl Res 13:162-168. 2002.

2.DeSmet, E., Jacobs, R., Gijbels, F., et al. The accuracy and reliability of radiographic methods for the assessment of marginal bone level around oral implants. Dentomaxillofacial Radiology 31:176-181. 2002.

QUESTION 7

According to the guidelines of the American Academy of Pediatric Dentistry, an avulsed central incisor in a 12-year-old, which has been out of the mouth for three hours

A. should be replanted immediately.

B. should be soaked in a fluoride solution before replanting.

C. requires pulp extirpation before replanting.

D. should not be replanted.

Rationale

The following are guidelines of the American Academy of Pediatric Dentistry for the management of an avulsed tooth of the permanent dentition:

– If less than two hours out of the mouth, replant immediately; if more than two hours, soak in 2% NaF solution for 5-20 minutes, then replant.

– If unable to replant immediately, transport, in descending order of preference, in Viaspan, Hank’s solution, chilled milk, saline, saliva, water.

– Semi-rigid splint for seven days.

– Consider antibiotics, analgesics and chlorhexidine rinses.

– Extirpate pulp in tooth with mature apex when splint is removed. In tooth with immature apex, monitor for signs of necrosis before initiating endodontic therapy.

– Ca(OH)2 treatment for 6-12 months, then gutta percha if no resorption.

The majority of replanted teeth demonstrate resorption within 2-5 years. The degree of resorption is closely related to the length of the extraalveolar time period. In instances of very prolonged extraalveolar dry time, replantation can be attempted. In such cases, the periodontal ligament should first be removed, the tooth soaked in fluoride, the root filled extraorally with gutta percha, the tooth rinsed in saline for two minutes, the blood clot removed gently from the socket and the replanted tooth splinted rigidly for six weeks to allow for ankylosis.

REFERENCE

Titley, K., Farkouh, D. Avulsed teeth-to replant or not to replant? Oral Health, July 27-29, 2002.

QUESTION 8

Oral lesions of lichen planus can be

1. white3. erosive

2. red4. vesicular

A. 1, 2, 3D. 4 only

B. 1 and 3E. All of the above

C. 2 and 4

Rationale

Dentists in clinical practice will regularly encounter patients with oral lichen planus (OLP). The oral form of lichen planus occurs more frequently than the cutaneous one and is more persistent and more resistant to treatment. Three different types of lesions of OLP are seen. Reticular OLP is the commonest but least severe form, which presents as a white, striated (lace-like) lesion, usually of the buccal mucosa. Atrophic OLP lesions are red and inflamed. Erosive OLP shows signs of shallow ulcerations, which can range in size. This is the most severe form of the disease, which causes considerable pain and interferes with eating, speech and quality of life.

There is no cure for OLP. Treatment is directed towards symptomatic relief of discomfort by use of topical corticosteroids. Topical agents such as fluocinamide 0.05% or clobetasol can be applied up to four times daily. In severe cases of erosive lesions, which are large, painful and debilitating for the patient and which are unresponsive to topical agents, systemic steroids may be required. In most cases, treatment is effective in reducing symptoms and inflammation and promoting healing of ulcerations. Lichen planus is believed to result from an abnormal T-cell mediated immune response in wh
ich basal epithelial cells are recognized as foreign. The cause of this is unknown. Patients with OLP should be followed closely as there is a slightly increased risk of developing squamous cell carcinoma at the site of the lesion, particularly in the erosive type.

REFERENCE

1.Chainani-Wu, N., Silverman, S. et al. Oral lichen planus. JADA; 132:901-909. 2001.

2.Edwards, P.C., Kelsch, R. Oral Lichen Planus: Clinical presentation and management. J Can Dent Assoc 68:494-499. 2002.

Answers to January 2004 SLSA Quiz

1. B

2. A

3. E

4. E


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