Quintessence International, 04/1995

Orthodontic relapse and tooth migration are comonly observed in patients with severe postorthodontic root resorption. If conventional removable retention is not adequate, fixed splint retention is necessary. Proponents of flexible splints suggest that the difference in mobility between natural teeth and the rigid systems is responsible for the loss of cement seal in the rigid systems. Proponents of rigid splints suggest that the flexibility that allows physiologic movement of the teeth also contributes to fatigue and subsequent failure of the material in the flexible splint systems. A clinical technique for increasing retention, consequently improving the prognosis of a resin-bonded fixed splint, is described.

Primary rubber dam retention affects attachment of the latex sheet to the anchor teeth bordering the isolated working field. Secondary rubber dam retention is the provision of an effective seal at the dam-tooth junction, which is essential to the maintenance of adequate access and moisture control within the working field. Practical hints are offered to optimize access and moisture control through well-planned and properly executed secondary retention of classic rubber dam applications. In addition, innovative solutions to the limitations of general field isolation, which pertain mostly to secondary retention of the unrestrained buccal and lingual curtains of the slit dam, are introduced.

When only the six anterior teeth remain, it may appear that indirect retention cannot be achieved because the fulcrum line around which the denture may move when the distal extensions lift away from the mucosa is located behind the retentive tips of the clasps on the abutment teeth. This will be the case when the indirect retainer and the tips of the clasps are on the same level; however, if the tips of the clasps are nearer to the gingival margin than the indirect retainer, indirect retentive effects will be achieved.

This study measured the distortion of one-piece base metal four-unit fixed partial dentures and recorded the effect of positioning marginal reservoirs on the wax patterns. Standard wax patterns were made in a special three-piece stainless steel mold. Twenty anterior prostheses were case: 10 for the experimental group and 10 for the control group. The prostheses were case in a nickel-chromium alloy and were measured with a traveling microscope with a micrometer scale. Premarked points were designated on gingivoaxial line angles for buccolingual and mesiodistal distances and diameters to record marginal discrepancies of specimens with or without marginal reservoirs. Castings with marginal reservoirs distorded signifiantly less than did the control fixed partial dentures.

The patient described in this case report required removal of several mandibular incisor teeth because of severe periodontal disease. She demanded an immediate replacement for these teeth, but, because of the periodontal conditions, it was not possible to use conventional approaches to fulfill her request. The decision was made to fabricate an immediate indirect-direct, reinforced, bonded composite resin periodonal prosthesis. The patient's extracted mandibular central incisors were used as pontic replacements. The procedure was expedient, inexpensive, and conservative, and the results were esthetic.

The clinical effectiveness of a new flossing device, the Floss Plus easy flosser, in reducing interproximal plaque and interproximal gingival inflammation was compared to the effectiveness of hand-held floss. The first phase studied 36 dental students while the second studied 26 adult patients undergoing supportive periodontal treatment. In both phases, the subjects were divided into two groups. One group used the flossing device, while the second group used hand-held floss. The Gingival Index and Plaque Index were taken at baseline, 1 week, and 6 weeks. All groups experienced a significant decrease in the amount of interproximal inflammation and plaque, regardless of which flossing method was used. There was no statistically significant difference between the two flossing methods in the reduction of interproximal inflammation or plaque. These results indicated that the Floss Plus easy flosser is as effective as hand-held floss in reducing interproximal plaque and gingivitis. The use of this aid may benefit those patients who lack the dexterity for hand-held floss or who find flossing cumbersome.

Ultrastructural changes in surface characteristics of enamel white-spot lesions were compared with changes in the adjacent clinically cound enamel after they were etched with 30% phosphoric acid. Ten human permanent first molars exhibiting natural white-spot lesions were used as study specimens. The lesion surfaces and their adjacent sound enamel were etched with 30% phosphoric acid for 60 seconds. Specimens were then evaluated by polarized light microscopy, scanning electron microscopy, and energy-dispersive spectroscopy. The acid etching produced a porous surface on both the white-spot lesion and the surrounding sound enamel. However, the lesion surface appeared to be more resistant to acid and dissolved less than adjacent enamel. This difference in acid solubility produced a steplike appearance between a white-spot lesion and its adjacent enamel surface. Energy-dispersive spectroscopy demonstrated no difference in relative calcium-phosphorus rations among the acid-etched white-spot lesion, acid-etched sound enamel, and unetched sound enamel.

Hypohidrotic ectodermal dysplasia is a rare congenital disease that affects several ectodermal structures. The disease is usually transmitted as an X-lined recessive trait in which the gene is carried by the female and manifested in the male. Manifestations of the disease differ in severity and may involve teeth, skin, hair, nails, and sweat and sebaceous glands. Most affected children require extensive dental treatment to restore their appearance and help the development of a positive self-image.

This in vitro study investigated the effect of dentinal bonding and ceramic etching procedures on the fracture resistance of all-ceramic crowns. These results were compared with the fracture resistance of similar crowns placed with a nonadhesive conventional cement. All results indicated that superior fracture resistance was obtained when dentinal bonding was incorporated into the luting procedure together with etching of the ceramic fitting surface and the use of resin-based luting material. The fracture resistance of specimens luted with such a procedure was significantly greater than that of specimens in which a conventional nonadhesive cement was used.