Comparison of the transfer precision of three different impression materials in combination with transfer caps for the Frialit-2 system.

Transfer of the precise position of implants to a master cast is a prerequisite for accurate and passive fit of the superstructure. Implants lack the mobility of natural teeth and, therefore, inaccurate frameworks result in stress within the mechanical parts and the implant-bone interface. Various impression methods have been described to achieve accurate reproduction of the intra-oral relation of the implants. The aim of this experimental study was to compare three different impression materials (polyether, polyvinyl siloxane, hydrocolloid) with the Frialit(R)-2 system and with the indirect technique. In addition, the use of transfer caps (TCs) to improve transfer precision was tested with all three materials. All measurements were performed using a three-dimensional (3D) co-ordinate measuring machine that is capable of locating points in space and calculating the relative distortions as angles of tilt (rot-XY, rot-XZ, rot-YZ) and 3D displacement. The results suggest that addition-silicone (a-silicone) and polyether are the materials of choice for implant transfer procedures. The use of TCs resulted in a significantly reduced rotation in the XY-plane but did not improve the absolute 3D displacement. A-silicone with the use of TCs proved to be most precise. Comparison between polyether and polyvinyl siloxane showed significant differences in the XY-rotation and the 3D displacement in favour of the silicone. Because the mean distortions between the original model and the master casts were about 100 microm, absolutely precise fit may be unattainable owing to the physical properties of the materials. Further studies will have to evaluate the amount of tolerable stress at the implant-bone interface.

Contemporary treatment of the resorbed avulsed tooth: a case report.

This report describes the treatment sequence after traumatic loss of a maxillary central incisor in a 15-year-old patient. Following extraoral root canal treatment and initially successful replantation, the case presented 9 years later with complete root resorption. After augmentation with an autologous mandibular corticocancellous graft, a dental implant was placed in a second stage surgery. The case highlights the challenge facing clinicians in providing the appropriate standard of care for today's treatment options.

Treatment of peri-implant defects with guided bone regeneration: a comparative clinical study with various membranes and bone grafts.

In this clinical study, a bioabsorbable membrane (Biofix) and two augmentation membranes made of expanded polytetrafluoroethylene (Gore-Tex) were tested for their osteopromotive potential. Forty-six implants were augmented with Gore-Tex membranes, 45 implants with titanium-reinforced Gore-Tex membranes, and 38 peri-implant defects with a resorbable polyglycolid membrane (Biofix). Autogenous bone (n = 85) and bovine bone matrix (Bio-Oss, n = 16) were used as filling materials beneath membranes. The results showed that bone repair is significantly improved by the use of membrane techniques. The average rate of bone regeneration with non-resorbable membranes was 84% (GTAM) and 81% (TR-GTAM). The use of Biofix membranes resulted in an average bone gain of 60%. The differences in efficacy established for the three types of membranes were found to be statistically significant (P < .001). Barrier membranes represent a valid technique for the treatment of peri-implant defects. Clinical and histologic results showed that Bio-Oss is an osteoconductive scaffold that promotes new bone formation.

[Clinical results and material behavior of composite, ceramic and gold inlays]. / Klinische und werokstoffkundliche Erfahrungen mit Komposit-, Keramik- und Goldinlays.

Laboratory-manufactured gold, ceramic and composite inlays were compared with the CAD/CAM produced CEREC inlay experimentally and clinically. The following systems were examined: Dicor, Optec, Hi-Ceram, Du-Ceram, Cerec, Kulzer, Coltene, SR-Isosit composite inlays, and gold inlays (Degulor C) with adhesive fixation (group I) and with zinc oxide phosphate cement (group II). In the clinical trial inlays in 270 teeth were re-evaluated in a total of 73 patients after 2.3 to 5 years. After 3 years the results obtained with Optec, Hi-Ceram and the Coltene composite inlay were less favorable than those of other systems--statistically however, this difference was of rather low significance (p less than 0.05). Fractures of ceramic inlays occurred in 6 cases within 8 months. 10 failures of ceramic and composite inlays were due to secondary caries.

[Periodontal aspects of removable partial dentures]. / Parodontale Gesichtspunkte bei der teilprothetischen Versorgung.

Periodontal pre-treatment of patients receiving partial dentures should involve three phases: initial therapy; periodontal surgery; home care. For periodontal surgery and/or prosthodontic treatment using precision materials, e.g. telescope retainers, the API (approximal plaque index) should not exceed 30%. To prevent further loss of gingival attachment due to iatrogenic irritation by the dentures preparation of abutments should consistently the para- or supragingival. In patients with few residual teeth telescope retainers, which can be cemented for definitive fit if indicated, are the treatment of choice.