The SLSA Program is based on a series of questions, answers, rationales and references followed by an annual 15-question quiz. All material is from current referenced literature. Completion of the quiz leads to CE points. Names and license numbers of dentists are forwarded to the appropriate licensing authorities.
QUESTION 29
For a patient with full arch implant supported fixed prostheses and a nocturnal clenching habit, the night guard should be
A. hollowed out over the implant crowns.
B. made to allow contact of only the posterior teeth in centric.
C. made to allow contact of only the anterior teeth in centric.
D. made to allow contact of only the anterior teeth in centric and excursions.
Rationale
Parafunctional forces can increase loads on teeth significantly and these loads can be sustained over long periods of time. In the case of implants, excess stress to the bone-implant interface can cause overload and resultant implant failure even after successful implant integration and placement of the final restoration. Use of a night guard is helpful to redistribute forces. Because of the periodontal membrane, teeth are able to cope with stresses better than implants. Unlike teeth, implants do not extrude in the absence of occlusal contacts. In patients with fixed partial prostheses the guard can be relieved in the implant region. When the implant restoration is in the maxilla, the guard is hollowed out so that no occlusal force is transmitted to the implant crowns. When the restoration is in the mandible, the occlusal surface of the guard is relieved over the implant crowns. When bilateral posterior regions are out of occlusion, muscle force in general is reduced. Therefore, when full arch implant supported fixed prostheses are opposing one another, the guard is fabricated so that only the anterior teeth contact during centric occlusion and excursions. This reduces forces on the implants.
REFERENCE
Misch, C.E. Clenching and its effect on implant treatment plans. Oral Health, Aug 11-21, 2002.
QUESTION 30
Lesions of recurrent herpetic gingivostomatitis are found on the
1. buccal mucosa.
2. hard palate.
3. soft palate.
4. lip.
A. 1, 2, 3
B. 1 and 3
C. 2 and 4
D. 4 only
E. All of the above
Rationale
Primary herpetic infection is more severe than recurrent infections and is associated with lymphadenopathy, fever and malaise. Recurrent infections occur at various intervals and affect the fixed intraoral tissues (hard palate and attached gingiva). The most common extraoral site for recurrent infection is at the vermillion border of the lip.
Acute and chronic forms of herpetic gingivostomatitis pose a risk for transmission. Non-infected dental professionals risk occupational exposure to oral herpes, herpetic whitlow of the digits and ocular herpes. Patients should be advised to minimize intimate contacts when active lesions are present.
Recognition of the classic signs and symptoms is important, as acute herpetic gingivostomatitis can complicate pre-existing conditions such as diabetes mellitus and renal disease and can be life-threatening in the immunocompromised patient.
REFERENCE
Ajar, A.H., Chauvin, P.J. Acute herpetic gingivostomatitis in adults: a review of 13 cases, including diagnosis and management. J Can Dent Assoc, 68i 247-251. 2002.
QUESTION 31
Bonded amalgam is superior to resin-modified glass ionomer cement in control of microleakage.
With composite resin, microleakage cannot be eliminated when the cavity margin is in dentine.
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
Complications from microleakage in a restoration include post-operative sensitivity, marginal discolouration, recurrent caries, pulpal inflammation and pulp necrosis. Many investigations of the phenomenon of microleakage have been carried out and there is general agreement that where enamel is present at the cervical margin, a better seal occurs. However, a further refinement relates to the bevelling of the enamel to effect an improved seal. Argument is made that the bevelling improves the etching pattern on the transverse cut enamel rods.
A recent report examined the effectiveness of various materials in prevention of microleakage in standard Class V cavities. The materials tested were resin-modified glass ionomer cement (RMGIC), composite resin, bonded amalgam, zinc oxide and eugenol, calcium hydroxide, gutta percha and silicate. The rank order of preventing bacterial microleakage from best to worst was: RMGIC (100%), bonded amalgam (88%), zinc oxide eugenol (86%), composite resin (80%), gutta percha (64%), calcium hydroxide (52%), and silicate (36%).
Several studies using composite resin have shown that where the gingival margin of the cavity is located on dentine only, complete elimination of microleakage cannot be achieved.
REFERENCES
1.Beznos, C. Microleakage at the cervical margin of composite Class II cavities with different restorative techniques. Operative Dentistry. 26:60-69. 2001.
2.Murray, P.E., Hafez, A.A., Smith, A.J. et al. Bacterial microleakage and pulp inflammation associated with various restorative materials. Dent Materials 18:470-478. 2002.
QUESTION 32
In the long term, for a patient with moderate to advanced periodontal disease, which of the following along with maintenance therapy will give the best result?
A. Scaling and root planing.
B. Osseous surgery.
C. Modified Widman procedure.
D. None of the above.
Rationale
Two recent studies have examined results of various treatments of moderate to advanced periodontal disease over a five-year period in groups of patients who were on maintenance therapy. These studies compared scaling and root planing, osseous surgery and the modified Widman therapies to determine if any one method was superior to the other. Data gathered allowed comparison of plaque and gingival indices, probing depth, clinical attachment levels and recession over the test period. Significant decreases in gingival and plaque scores were recorded and with all methods there was a reduction in probing depths. Only slight attachment level changes were recorded. Thus, with good patient maintenance, satisfactory results can be achieved with or without surgery.
REFERENCE
1.Becker, W., Becker, B.E., Caffesse, R. et al. A longitudinal study comparing scaling osseous surgery and modified Widman procedures: Results after five years. J Periodontol. 72:1675-1684. 2001.
2.Loesche, W.J., Giordano, J.R., Soehren, S. et al. The non-surgical treatment of patients with periodontal disease: Results after five years. JADA. 133:311-320.2002.
Answers to July 2004 SLSA Quiz
25. A
26. A
27. E
28. E
