Quintessence International, 12/1993

This paper describes the combined efforts of an orthodontist periodontist, and a restorative dentist to save an unrestorabl e tooth by clinical crown lengthening. A maxillary lateral incisor, originally treatment planned for extraction, was treated with orthodontic extrusion, circumferential fiberotomy, and metal-ceramic crown restoration. To maximize the esthetic appearance of the tooth during orthodontic treatment, an acrylic resin facing was designed together with the orthodontic appliance used to facilitate vertical extrusion. Clinical crown lengthening may be used as an alternative approach to the treatment of severely broken down anterior teeth.

Irregularity of the mandibular incisors in an otherwise good occlusion is quite common in young adult patients. Through use of enamel stripping in the incisor region, it is possible to create sufficient space to align the teeth with a mandibular sectional removable appliance, commonly known as the spring aligner. This article reviews the methods of enamel stripping and describes the author's preferred technique of enamel stripping and the various modifications of the spring aligner appliances that can be prescribed by the general practitioner to correct mandibular anterior crowding.

A new surgical technique can promote complete root coverage in deep and wide recessions. A root isolation procedure with expanded polytetrafluoroethylene membrane is combined with tetracycline treatment of the root surface and fibrin-fibronectin glue application. Treatment of two patients resulted in the disappearance of the anatomic defect and an increase in the amount of keratinized gingiva.

The purpose of this study was to compare, in vivo, in 30 teeth destined for extraction, the abilities of the Scalex rotary bur system and Gracey curettes to obtain a smooth root surface. The time taken for each treatment was also evaluated. The profilometry results showed no significant differences between instruments with regard to roughness or working time, in single-rooted teeth, multirooted teeth, or in pockets of 5 mm or more. Only for distal longitudinal roughness and in pockets less than 5 mm did the Scalex system perform slightly better. There was some improvement in working time when the distal surfaces were instrumented with Scalex. Both systems demonstrated a similar capacity to render smooth surfaces.

The purpose of this in vivo study was to evaluate the microleakage of indirect composite resin inlays and to determine the thickness of composite resin luting material. Twenty periodontally involved posterior teeth scheduled for extraction were selected and Class II cavities were prepared. Ten cavities had gingival margins placed in enamel above the cementoenamel junction, and the other 10 were placed in dentin below the cementoenamel junction. Six months after cementation, the teeth were extracted and analyzed. The leakage was higher in inlays with gingival margins in dentin than in inlays with gingival margins in enamel. The cement thickness was between 15 and 40 um, a clinically acceptable range.

Porosities in composite resin can be incorporated at many stages of packaging and placement. Porosities can be minimized through vacuum loading of syringes and use of light-curing materials that require minimal handling. Even so, the method of placement of the material can lead to inclusion of submicron bubbles in the resin or formation of structures and pockets that can trap air at the surface. The consequences of material viscosity, method of placement, and cavity design are examined in relation to porosity incorporation.

The effect of cuspal coverage on the in vitro fracture resistance of teeth restored with indirect composite resin inlays was examined. After standardized preparation differing only in cavity width, two groups of teeth were restored with indrect composite resin restorations. Two further groups of teeth were prepared in a similar manner, except that the buccal and palatal cusps were reduced by 2 mm, and cuspal-coverage indirect composite resin restorations placed. In another group, indirect composite resin restorations with only palatal cuspal coverage were placed. One group of intact teeth acted as a control. Forces were applied to the restored teeth by means of a 4-mm steel bar in a Universal testing machine. For each of the preparation designs assessed, the fracture load for onlays was greater than that for equivalent inlays; the onlay fracture strength was equivalent, for some preparation designs, to that of sound teeth.

Although careful mixing of alginate material will reduce the number of airborne particles, some will always be observed directly above the site of spatulation. An alternative method of dispensing, mixing, and delivering alginate impression material is introduced. This technique not only protects dental personnel but also results in a creamier mix and a superior impression.

The use of posterior composite resins has grown considerably over the past 5 years. While most research efforts have been devoted to improving wear resistance, little effort had been made to determine possible wear of the cusp of the opposing tooth. A recently developed in vitro wear system was used to evaluate a series of composite resins for their ability to abrade opposing enamel c usps. When the resins were tested under the same conditions, a considerable range in enamel wear was observed. Representing opposite ends of the scale, the quartz-containing composite resin caused the enamel to wear away ten times more than did the microfilled composite resin.