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Learning Assessment (April 01, 2000)

April 1, 2000
by Oral Health


The SLSA program is based on current, referenced literature and consists of 40 questions, answers, rationales and references, followed by a 15-question quiz.

Dentists who complete the quiz 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 13

In endodontic treatment, an ideal intracanal medicament should eliminate microorganisms, reduce inflammation and pain, stimulate repair, be biocompatible and control apical haemorrhage. Which of the following meet all these requirements?

1.Camphorated monochlorophenol (CMCP)

2.Sodium hypochlorite (NaOCl)

3.Calcium hydroxide

4.Chlorhexidine gluconate

A.1 and 2

B.2 and 3

C.1, 2, 3

D.All of the above

E.None of the above

Rationale:

A recent review of endodontic medicaments concludes that no single medicament meets all the requirements listed. Antimicrobial medicaments must be recognized as only supplementary to thorough and careful instrumentation. Meticulous debridement and irrigation are much more important than what is placed in the canal. It has been shown that the above medicaments are mainly unsuccessful in reducing interappointment pain, when compared to dry or saline cotton pellets.

Camphorated monochlorophenol and other phenols, including eugenol, are effective antimicrobials, but they are toxic and much of their efficacy is lost after 24 hours. Sodium hypochloride is useful as an irrigant because it can dissolve necrotic debris; poor results are reported, however, in dissolving pulpal tissue from fins and isthmi in root canals.

Calcium hydroxide, due to its high pH of nearly 12, has some antimicrobial effectiveness, but results are dependent upon the time left in the canal-the optimum time being one week.

Chlorhexidine gluconate has been suggested as both an irrigant and a medicament. It is effective against many bacteria, yeasts and fungi. Having a cationic molecule, it binds to the tooth and bacteria, and is released slowly for up to 24 hours. The use of chlorhexidine for endodontics is under further study.

REFERENCE:

Doran, M.G., Radtke, P.K., A review of endodontic medicaments. J General Dent Oct:484-88, 1998.

QUESTION 14

A 10 year old girl has partial anodontia (hypodontia) with two missing maxillary lateral incisors. Her mother asks you to correct this with implants. You would

A.place implants.

B.delay implant treatment until the pubertal growth spurt.

C.delay implant treatment until after post pubertal growth.

Rationale:

The replacement of missing maxillary lateral incisors with implants in growing patients should only be attempted after the potential growth status of the patient has been ascertained. Hand-wrist radiographs provide the best method for determining the maturational status of a pubertal patient. No implant should be placed in the anterior maxillary region during the accelerating phase of pubertal growth or before. Implants in the anterior maxillary region of circumpubertal females should be placed at an age coinciding with the decelerating phase of the pubertal growth spurt or later. The growth of the average 10 year old girl would not have slowed sufficiently for implants to be placed.

If the implants are placed prior to final growth of the maxillary alveolus, the implants will not move with the alveolus as growth proceeds and will come to lie in a palatal position with a poor esthetic result.

REFERENCE:

Ranly, D.M. Implants in the circumpubertal patient: Growth considerations. Am J Dent 11:86-92, 1998.

QUESTION 15

When veneers are used to improve esthetics, a full veneer preparation should be planned for the treatment of

1.malalignment

2.diastemas

3.discolouration

4.gingival recession at the embrasure.

A.1, 2, 3

B.1 and 3

C.2 and 4

D.4 only

E.All of the above

Rationale:

The full veneer technique is most appropriate when tooth position or size needs to be altered, enamel augmentation is needed, or major colour masking is demanded. When using veneers on malaligned teeth to create the illusion of well-positioned teeth, a full veneer allows appropriate build-up of enamel. Such veneer treatment is also recommended for diastemas. The proportion of tooth size can be better matched with a full veneer. In cases of discoloured teeth, the full veneer eliminates the dark shadows at the edges. Where gingival recession has occurred with spaces in the embrasures, a traditional veneer preparation results in elongation of the tooth and widening of the facial contact. A full veneer preparation can be used to prevent these anatomic irregularities.

When preparing a tooth for a full veneer, the cut should extend to the lingual of the tooth, breaking the interproximal contact. Interproximal enamel is thick and allows this extension with little involvement of dentin. With this technique, however, prepared teeth must be well temporized to prevent migration and sensitivity.

REFERENCE:

Route, J.S. Full veneer versus traditional veneer preparation: A discussion of interproximal extensions. J Prosth Dent 78:545-549, 1997.

QUESTION 16

If you detect early signs of ectopic eruption of a maxillary canine in a patient age 9 years with a Class I uncrowded dentition in which the canine crown is distal to the midline of the lateral incisor, you would

A.observe

B.extract the deciduous canine immediately

C.delay extraction of the deciduous canine until age 12

D.surgically expose the crown and guide the tooth into normal alignment

Rationale:

In the prevention of maxillary canine impaction, if a clinician detects early signs of ectopic eruption of the canines, selective extraction of deciduous canines should be made as early as 8 or 9 years of age as an interceptive approach to canine impactions in Class I uncrowded cases. Erickson and Kurol suggest that removal of deciduous canines before 11 years of age will create a normal position of ectopically erupting permanent canines in 91 percent of cases, if the canine crown is distal to the midline of the lateral incisor.

If the canine crown is mesial to the midline of the lateral incisor, chances of normal eruption of the canine decrease. A further important prognostic factor in addition to the position of the impacted tooth is the severity of its angulation. The more inclined the tooth is, the less the probability of spontaneous eruption.

Possible sequelae of canine impactions range from loss of space in the arch to resorption of roots of the neighbouring teeth. It is therefore imperative to manage the ectopically erupting canine as early as possible.

REFERENCES:

1.Bishara, S.E., Clinical management of impacted maxillary canines. Seminars in Orthodontics. 4:87-98, 1998.

2.Erickson, S., Kurol, J., Early treatment of palatally erupting maxillary canines by extraction of primary canines. Eur J Orthod 10:283-95, 1988.


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