A study into the sensitivity and accuracy of a standardized radiographic technique for the disclosure of root resorption cavities was performed in a cadaver material. Film contrast and horizontal angulation were varied in order to identify factors in radiographic exposure which resulted in the greatest diagnostic reliability. In an autopsy material of 5 jaw blocks containing both mandibular premolars, “small, medium and large” cavities simulating root resorptions of 0.6, 1.2 and 1.8 mm in diameter and 0.3, 0.6 and 0.9 mm in depth, respectively, were drilled at the cervical, middle and apical thirds of the proximal and oral root surfaces of the premolars. Cavity locations were distributed to ensure an equal number of locations with and without cavities and an equal number of cavities of each size. Results of the investigation indicated that the small cavities were never visualized, nor were 6 out of 13 medium cavities nor 1 out of 13 large cavities; that cavities located proximally were more readily seen than those located orally and that there was no clif Terence in cavity visualization between cavities on the apical, middle or cervical thirds of the roots; high density (contrast) films allowed the best cavity visualization. Finally, radiographs from the time of injury (i.e. preresorption radiographs) as well as radiographs taken at various horizontal angulations were found to be of importance in order to increase the possibility of cavity visualization.

Dentin-bonded RP applied onto the entire, slightly concave resection surface is a predictable apical sealant characterized by a high success rate. In contrast, retrograde root filling with CS results in an unacceptably high failure rate due to insufficient bonding strength to the concave resection surface.

No abstract

– Radiographic assessment of marginal bone height is included in longitudinal control of osseointegrated implants. Previous studies have revealed a mean annual loss of less than 0.1 mm. The purpose of the present study was by means of an experimental model to analyze the influence upon alveolar bone height measures around osseointegrated implants of buccolingual bone dimensions as well as angulations of fixture axis to central X‐ray beam. Brånemark titanium implants were inserted into acrylic test blocks simulating alveolar ridges of various widths. 0.2 mm steel wires visualized buccal and lingual bone margins. Standardized radiographs were obtained by stepwise variation of projection angles. Separation of the wire images varied from 0.1 mm (buccolingual width 5 mm and 1° angulation) to 4.8 mm (width 13 mm and angulation 20°). In clinical cases distortion of buccal and lingual bone margins may result in overestimation of bone heights. The degree of overestimation is influenced by the buccolingual position of the fixture. Strict parallelism between fixture axes and film plane is essential to obtain valid results using single films.

No abstract

The absence of a peri-implant radiolucency on radiographs is used as a criterion for implant success. The purpose of the present study was to evaluate the accuracy of diagnosing peri-implant radiolucencies using an experimental model. Astra Tech fixtures were inserted into 20 bony specimens. Later, the fixtures were removed and the prepared cavities were enlarged in 2 steps. The specimens were radiographed under strictly standardized circumstances in the 3 stages ("press-fit" = simulated osseointegration, and "0.1 mm space" and "0.175 mm space" = simulated connective tissue layer). All specimens were radiographed with 2 vertical angulations (0 degree and 15 degrees). Ten observers read the radiographs and evaluated bone-implant relationship on a 5-point scale. The interobserver agreement was low. Specificity was remarkably low, and sensitivity was moderate. A significant difference in diagnostic accuracy was found for 0.175 mm peri-implant-space compared to 0.1 mm space. The diagnostic accuracy was found to be highest for 0.175 mm peri-implant space specimens. It is concluded, that radiography seems to be an unreliable method for diagnosing peri-implant spaces, although accuracy improved at increasing space widths. Strict orthogonal projection angles did not improve diagnostic accuracy.

The aim of this study was to evaluate the marginal tissue response adjacent to implant supported overdentures. Twenty edentulous patients had 2 Astra Dental Implants placed in the canine region of the lower jaw. New overdentures were retained by individual ball attachments in 11 patients and by a bar attachment in 9 patients. Periodontal registrations were recorded 0 months, 6 months, 12 months and 24 months after the overdentures were inserted. One of the 40 fixtures was lost at the stage of abutment connection. No fixtures were lost during the 2- to 4-year observation period and no fixtures showed any periodontal signs of failure. At the 2-year examination, no pocket depths adjacent to the implants exceeded 4 mm and no bone loss exceeded 3 mm. The mean annual bone loss was less than 0.2 mm during the first 2 years. The preliminary results from this limited study were promising and showed that two osseointegrated Astra Dental Implants could successfully retain an overdenture in the lower jaw. However, long-term observation is needed for a definitive evaluation of this treatment concept.

The present long-term study indicates that RP can be used for root-end filling with a successful treatment outcome.