David A. Kaiser

Surgical guide for dental implant placement

Restorative problems with less than desirable implant placement can be challenging. A procedure is presented for the fabrication of a surgical guide stent that dictates placement of dental implants. This surgical guide can enhance implant placement in an efficient and acceptable manner so that final restorations can be properly contoured and esthetic.

Long-term changes in soft tissue height on the facial surface of dental implants.

The success of osseous healing around dental implants has allowed for an increased emphasis on soft tissue healing and esthetic results. However, there is limited information profiling the long-term healing of the soft tissues following prosthesis placement. The purpose of this study was to assess the long-term changes in the position of the facial soft tissue margins following restoration of a one-stage implant system. One hundred and six one-stage ITI implants were evaluated in 39 patients. Implants were placed in maxillary and mandibular anterior regions. Clinical assessment of the soft tissues on the midfacial aspect of the implants was performed over a 2-year period, at 3 and 6 month intervals, following placement of the final restoration. A total of 63 implants were placed as multiple units in the mandible, 23 as single units in the maxilla, and 20 as multiple units in the maxilla. There were no implant failures over this time period. Overall, on the facial aspect of 61% of the 106 implants there was 1 mm or more of soft tissue recession, whereas 19% of the implants showed 1 mm or more of gain in soft tissue height. There was a significantly (P < 0.01) greater number of implants showing a gain in soft tissue levels in the mandibular implants compared with the maxillary implants. Of the 39 patients assessed, 24 showed a loss and five showed a gain of 1 mm or more of the soft tissue levels around the implants. Overall, there was a significant decrease in the mean levels of tissue height of 0.6 mm within the first 6 months, with relatively little change afterward. However, in evaluating only patients showing a loss in tissue height around one or more implants, the mean loss in tissue height was 1.6 mm after 24 months. These results suggest that the potential for significant changes in soft tissue levels after completion of restorative therapy need to be considered for implant therapy in esthetic areas.

Thickness and marking characteristics of occlusal registration strips

T he practice of clinically marking and evaluating occlusal patterns or “high spots” has been empirical to dentistry. Dentists have used ink, silk ribbon with colorants, colored paper, plastic strips with colorants, and wax to visualize occlusal contacts. Little has been reported on the accuracy of the registration materials. Dawson’ suggested that thin silk ribbon was the most efficient method of marking interferences. Halperin et a1.2 studied marking materials to determine thickness, strength, and plastic deformation. They concluded that occlusal registration strips should be less than 21 pm thick and capable of plastic deformation. In addition, they stated that paper was a brittle material and therefore should not be used. Clinical observations revealed that commercially available occlusal registration materials produced a wide range of marks from small, sharply defined areas to broad, ill-defined smudges. 3-5 Information is needed on the variables that affect the size of the mark. Manufacturers’ designations of registration strip thickness presently are not standardized. Descriptions such as microthin, extra thin, extra-extra thin, and thick have only a rough qualititative relationship to the true strip thickness or mark size. Depending on the physical properties of a registration strip, a product may mark the actual contact area or generate a misleading smear or smudge in a noncontacting area. The purpose of this study was to investigate the relationship between registration strip thickness and area of the mark produced under dry laboratory conditions.

Shear bond strengths and scanning electron microscope evaluation of three different retentive methods for resin-bonded retainers

T he “Maryland bridge” with resin-bonded retainers has been well described in the literature.‘-‘3 Electrolytically etching the base metal markedly improved the bond strength between the metal and resin.8J0 However, to avoid contamination by saliva and foreign substances on the internal surface of the retainer, etching has been advocated after a try-in appointment.‘0~‘2 Because of the laboratory equipment needed and the sensitivity of the electrolytic technique, dentists have limited control of the quality of the metal etch. Table I. Composite shear bond strengths (megapascals)

Mandibular centricity: Centric relation

Centric relation can be a confusing term because it continues to evolve in meaning. This article presents a discussion of the historical aspects of centric relation. Guidelines to decide when to use centric relation in clinical dentistry are included.

Marginal distortion of cast restorations induced by cementation

Eleven full veneer crowns were directly constructed on brass stylized dies. Crown marginal openings and vertical heights were measured before and after cementation with zinc phosphate cement. The following results were established. The marginal opening of complete veneer gold crowns increased during cementation. The vertical heights of well fitting crowns also increased significantly after cementation.

A 5-Year Prospective Multicenter Clinical Trial of Non-Submerged Dental Implants With a Titanium Plasma-Sprayed Surface in 200 Patients

BACKGROUND Endosseous dental implants are a popular treatment to replace missing teeth. Although many advances have occurred and affected the macrogeometry and surface characteristics of dental implants, among other aspects, it is important to document how the implants perform in patients over time. Such evaluations are helpful not only to document the clinical survival of the implants but also patient satisfaction over an extended period. METHODS A formal prospective multicenter human clinical was performed at five centers involving 200 patients and 626 implants. Specific inclusion and exclusion criteria were used and detailed data collected at specified times using case report forms. An independent study monitor reviewed all study data before entry into the study database. Two implant designs were used in two different clinical indications. A non-submerged titanium plasma-sprayed (TPS) hollow cylindrical implant with a smooth transgingival collar was evaluated in the maxillary anterior sextant and a non-submerged TPS solid screw implant with similar collar in the mandible. RESULTS Over the course of the 5-year clinical trial, there was one early failure occurring before definitive prosthesis delivery. Three late failures were documented, one occurring at each of the 6, 12, and 18 months postoperative visits. Life table analysis at 5 years revealed a 99.4% survival rate and a 92.5% success rate. Patient satisfaction was rated as good to excellent for 96.1% of implants in regards to esthetics after 5 years; 98.8% for appearance; and 99.4% for prosthesis comfort, ability to chew and taste, fit, and general satisfaction. No serious adverse events were reported. CONCLUSIONS Implant success and survival was over 92% and 99%, respectively, in a formal 5-year prospective multicenter clinical trial involving 200 patients and 626 non-submerged TPS implants. These implants included hollow cylinder implants in the anterior maxilla and solid screw implants placed in the mandible. These findings document the predictability and patient satisfaction of tooth replacement using a non-submerged surgical technique involving a tissue-level, rough surfaced endosseous dental implant.

Provisionalization for a single cementable dental implant restoration

This article presents a procedure for refining margins of provisional implant crowns. This procedure uses an analog of the implant and abutment. This procedure allows functional and esthetic considerations such as emergence profiles, symmetry, diastemas, embrasures, size, contours, position, angulation, and relation to other teeth to be evaluated.

Shear bond strength of two resin adhesives for acid-etched metal prostheses

This study compared the shear bond strength of Panavia EX and Comspan Opaque adhesive resins with electrolytically etched or sandblasted Rexillium III or Litecast B metals bonded to extracted teeth. An analysis of variance revealed that there is no difference in bonding strength among etched or sandblasted Rexillium III metal with either Panavia EX or Comspan Opaque resins. With Litecast B metal, sandblasting produced a greater bond strength than etching with Panavia Ex resin (38.19 MPa sandblasted; 30.53 MPa etched). Conversely, Comspan Opaque resin had a value of 30.10 MPa etched and 15.40 MPa sandblasted. The etched Rexillium III and Panavia EX resins recorded a greater bond strength (38.38 MPa) than Comspan Opaque resin (27.83 MPa) or sandblasted Rexillium III metal (Rexillium III 34.74 MPa; Comspan Opaque 20.39 MPa) and Litecast B metal (Panavia EX 38.19 MPa; Comspan Opaque 15.40 MPa). Eighty percent of the failures occurred at the cement-metal interface with both cements.

A new gingival retraction impression system for a one-stage root-form implant

Displacement of soft tissue adjacent to an implant abutment is arduous. Currently, gingival retraction cord is used before making an impression for cement-retained implant restoration. This article presents a new impression system for a cementable abutment/implant. The advantages of a cement-retained implant crown are described. This system provides efficient and accurate impressions.