Learning Assessment (February 01, 2001)

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, 2001 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.


Refractory periodontitis:

A. is a separate periodontal disease entity.

B. is characterised by having a single site which does not respond to conventional treatment.

C. shows minimal loss of attachment.

D. shows minimal loss of alveolar bone.


Most patients respond to conventional periodontal therapy. However, a small group, irrespective of treatment and home care, seems to continue to decline. Bone loss and attachment loss continue to occur in multiple sites throughout the mouth. Such a disease state has been called refractory periodontitis, and it is considered a separate entity. Two rates of attachment loss have been recorded in these cases, and each pattern appears to be related to the infecting microflora. Rapid loss is characterized by the presence of Gram-negative flora with Spirochetes, Prenotella intermedia, and Fusobacterium organisms. Slower attachment loss is associated with Gram-positive flora in which Spirochetes intermedius are in high numbers.

Research has shown that a response can be expected in both categories after the use of a seven-day course of clindamycin given in conjunction with full mouth scaling and oral hygiene. A recent study has demonstrated that metronidazole can also be used to produce a favourable result in conjunction with scaling, root planing, and oral hygiene.


1. Walker, C.B., Gordon, J.M., Magnusson, I., et al. A role for antibiotics in the treatment of refractory periodontitis. J Periodont August (Supplement) 64:772-781, 1993.

2. Sder, B., Nedlich, U., Li, J.J. Longitudinal effect of non-surgical treatment and systemic metronidazole for 1 week in smokers and non-smokers with refractory periodontitis: a 5-year study. J Periodontol 70:761-771, 1999.


Dental implants can exhibit peri-implant inflammation, which is

1. the same as periodontal disease of the natural dentition.

2. due to the biomechanical overload.

3. caused by bio-incompatibility of the implant.

4. plaque induced.

A. 1, 2, 3

B. 1 and 3

C. 2 and 4

D. 4 only

E. All of the above


Cause of peri-implant tissue breakdown is multifactorial, but bacterial infection and biomechanical overload are the major causes. Poor surgical techniques can also induce peri-implant disease. Avoidance of overloading of implants is crucial to their success. This is influenced by the number and position of implants, quality of bone, and the distribution of prosthetic and functional forces.

Soft tissue around an implant differs from that related to natural teeth. There is no periodontal ligament. Instead, gingival connective tissue adheres to the implant and collagen fibres run parallel to the implant surface.

“Peri-implant mucositis” describes inflammation limited to the soft tissue, whilst “peri-implantitis” refers to peri-implant bone loss secondary to inflammation.

The control of soft tissue inflammation around an implant is essential for long-term implant success. The inflammation seen in the soft tissue around the implant would appear to be related to bacterial plaques. It should be noted that subgingival bacteria associated with inflamed implant sites differ from the flora around healthy implants, similar to that occurring around natural teeth.

Implant materials are bio-compatible, but the microscopic rough porous surface, though not a causative factor itself, may harbour plaques and their organisms to produce soft tissue inflammation with the appropriate microbial shift.

To offset these difficulties, patients should have a regular regimen of maintenance hygiene visits with evaluation of bone levels from original base line data. Gentle probing with fixed reference points on the abutments to allow for comparative recording is recommended. Microbial monitoring is also useful in evaluating the health status of the implant. Patient instruction on cleaning with brushes, floss, pipe cleaners, as well as chlorhexidine gluconate mouthwash will reduce the plaque irritants.


1. Jovanovic, S.A. Peri-implant tissue response to pathological insults. Adv Dent Res 13:82-86, 1999.

2. Eskow, R.N., Smith, V.S., Preventive peri-implant protocol. Compend Contin Educ Dent, 20:137-152, 1999.


In an amalgam-filled posterior tooth involving the occlusal and interproximal surfaces, which of the following is/are good predictors in the diagnosis of recurrent caries?

A. A radiolucency on a bite wing radiograph

B. Ditching of the amalgam.

C. Discolouration around the restoration

D. All of the above.

E. None of the above.


Provided the filling materials (including base and liner) are radio-opaque, recurrent lesions are readily visible as radiolucent areas. Therefore, bite wing radiographs of posterior teeth are usually the best diagnostic tools to identify recurrent caries.

Ditching usually occurs on the occlusal surfaces of amalgams but several studies have demonstrated that this is not indicative of recurrent caries.

Discolouration around an amalgam restoration with clinically intact margins is a poor predictor of the presence of secondary caries beneath the restoration.

Thus an amalgam restoration should not be replaced on the basis of observed staining or ditching around it. Tooth-coloured filling materials present more difficult problems of interpretation. This relates to staining and colour change, as well as radiographic evidence.


1. Kidd, E.A.M. The operative management of caries. Dent Update 25:104-110, 1998.

2. Kidd, E.A.M., Joyston-Beehal, S., Beighton, D. Marginal ditching and staining as a predictor of secondary caries around amalgam restorations: a clinical and microbiological study. J Dent Res 74:1206-1211, 1995.


Formation of white spot lesions on facial surfaces of teeth of patients undergoing orthodontic therapy is a problem. The successful remineralization of these lesions is dependent upon the

1. pH of saliva

2. frequency of the cariogenic challenge (acid demineralization)

3. mineral ion concentration of the saliva

4. availability of mineral ions in saliva.

A. 1, 2, 3

B. 1 and 3

C. 2 and 4

D. 4 only

E. All of the above


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.

Remineralized lesions are more resistant to further carious attack than the adjacent sound enamel.

The white spot lesions frequently found after removal of orthodontic brackets pose a particular clinical problem. These lesions form under and adjacent to the brackets and bands because of plaque retention.

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 to the teeth. Kleber et al. (1999) noted that a three-month treatment of orthodontically induced white spots reduced the lesion area and increased the tooth gloss. Such an approach to this problem is advocated involving the home tooth brushing with a dual-phase, remineralizing fluoride dentifrice, twice per day for one minute. By supplementing brushing with a mouth tray application of the dentifrice for five minutes per day, remineralization was accelerated.

An added benefit of this remineralizing toothpaste relates to its ability to decrease dentin sensitivity. This is probably due to blockage of open dentinal tubules. Upon completion of adult orthodontic therapy, there is often recession with exposed root surfaces with resultant sensitivity.


1. Kleber, C.J., Milleman, J.L. Davidson, K.R., et al. Treatment of orthodontic white spot lesions with a remineralizing dentifrice applied by tooth brushing or mouth trays. J Clin Dent 10:44-49, 1999

2. Kaufman, H.W., Wolff, M.S., Winston, A.E. et al. Clinical evaluation of the effect of a remineralizing toothpaste on dentinal sensitivity. J Clin Dent 10:50-54. 1999.

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

Answers for February 2001 SLSA questions:

5. A 6. C 7. A 8. E