Based on the present systematic review, all-ceramic crowns, when used for anterior teeth, showed survival rates at 5 years comparable to those seen for metal-ceramic crowns. When used for posterior teeth, the survival rates at 5 years of densely sintered alumina crowns (94.9%) and reinforced glass-ceramic crowns (93.7%) were similar to those obtained for metal-ceramic crowns. Furthermore, lower survival rates of 90.4% and 84.4% can be expected for InCeram crowns and glass-ceramic crowns when utilized for premolars and molars.
The principle of guided tissue regeneration has been successfully applied for the regeneration of bone in various jaw defects in human. The purpose of this study was to assess the bone volume regenerated using nonresorbable membrane barriers. Nineteen patients with jaw bone defects of various sizes and configurations were included in the study. Combined split-thickness/full-thickness mucosal flaps were elevated in the area of missing bone. The size of the defects was assessed by measuring the distance from a reference line between 2 adjacent teeth (cementoenamel junctions) to the alveolar crest (a) every 2 or 3 mm. In addition, the crestal width was measured. Consequently, the surface of the triangle formed by a and the width of the crest as well as the volume between all triangles were calculated geometrically. Following the placement of Gore-Tex augmentation material as a barrier, the distance (b) to the top of the membrane from the reference line was assessed, and the maximum possible volume for bone regeneration based on (a-b) and the width of the crest was calculated. At the time of membrane removal (3-8 months later), the same measurements were performed and the percentages of regenerated bone in relation to the possible volume for regeneration determined. In 6 patients in whom the membranes had to be removed early due to an increased risk for infection between 3 and 5 months, bone regeneration varied between 0 and 60%. In 13 patients in whom membranes were left for 6-8 months, regenerated bone filled 90-100% of the possible volume.(ABSTRACT TRUNCATED AT 250 WORDS)
The aim of this study was to determine the threshold of tactile perception of endosseous dental implants and to assess the relative difference of that threshold between implants and teeth. Twenty-two subjects with implants of the ITI Dental Implant System were included in the study. All implants served as abutments for single tooth crowns and had been in function for a minimum of 1 year. A strain gauge glued to the shaft of an amalgam plugger served as a force sensor. It transformed the elastic deformation exerted onto the shaft into an electronic signal for recording. By use of the amalgam plugger, a continuously increasing force was exercised on the implants or teeth until the first sensation of touch was indicated by the patient. Statistical analysis revealed threshold values for the implants ranging from 13.2 to 189.4 g (1 g = 0.01 N) (mean 100.6; SD 47.7), while a range of 1.2 to 26.2 g (mean 11.5; SD 11.5) was found for control teeth. Thus, the mean threshold values for implants were 8.75 times higher than for teeth. This difference was highly statistically significant. A general linear models procedure was applied to determine the influence of patient age, jaw, implant position and the threshold values of teeth on the measurements obtained for implants. Only gender and the threshold values for contralateral teeth had a significant influence. These 2 parameters together explained 27% of the variability in threshold measurements. It is concluded that a more than 8-fold higher threshold value for tactile perception exists for implants compared with teeth.
The installation of implants directly into extraction sockets offers considerable advantages over other treatment modalities for both practitioners and patients. Usually, immediate implants are placed and subsequently covered by mucosa allowing a submerged healing mode. This report presents the rationale, clinical procedures and results for immediate transmucosal implants. Following an intracrevicular incision and flap elevation, the tooth to be extracted is carefully luxated by means of small elevators to preserve the entire bony housing of the tooth. A titanium plasma-sprayed implant (ITI Bonefit) is then installed at the bottom or in the wall of the extraction socket. An expanded polytetrafluoroethylene barrier membrane (Gore-Tex GTAM) is tightly adapted around the implant post and over the bony margins of the alveolus. The flaps are then replaced, adapted around the neck of the implant and sutured. During nonsubmerged, transmucosal healing of the site, meticulous plaque control is performed by mechanical and chemical means. Membranes are removed after 5-7 months. Since infection was prevented, the implants obtained stability, healthy peri-implant mucosal tissues were observed and missing bone in the alveoli regenerated. Of 21 transmucosal implants placed into fresh extraction sockets, 20 yielded complete bone fill and coverage of the entire plasma-coated implants surface at the time of membrane removal. This documentation suggests that the immediate nonsubmerged installation of an implant into an extraction socket is a predictable treatment modality with good long-term prognosis.
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