The clinical relevance and correlation between the initial straight length to the first curvature in human second maxillary premolars.

The aim of this study was to evaluate the straight lengths of the root canal of human second maxillary premolars using standardized radiological techniques in vitro. The distances were examined starting from the cemento-enamel junction (CEJ) to the appearance of a curvature. In particular recommendations which may facilitate decision making with regard to the length of post systems after successful endodontic treatment should be available. Extracted human second maxillary premolars (n = 210) were used; teeth with root caries, artificial crowns, extensive fillings or with previous endodontic treatment were excluded from this investigation. The teeth were fixed in a specially developed device with standardized and reproducible distances and digital radiographs using the parallel technique were made. A descriptive statistical analysis and the calculation of the cumulative frequencies were made. The values for the distance starting from the CEJ to a first curvature were as follows: a) For right second premolars: median value=10.3 mm (min.: 5 mm; max.: 15.8 mm) and mean value= 10.4 SD+/- 2.6 mm; b) left second premolars: median value =10.2 mm (min.: 5 mm; max.: 17 mm) and mean value =10.3 mm SD +/-2.2 mm. Based on our data, high number of second maxillary premolars showed a curvature (30.4%) 9 mm apically from the CEJ. These findings should be taken into consideration for endodontic treatments and post insertions.

Clinical situation of the coronal part of the teeth including restorations types placed prior to endodontic treatment - a retrospective study.

AIM: In the present retrospektive study the situation of the natural crown as well as the restoration types placed prior to endodontic treatment was examined. MATERIALS AND METHODS: A total of 782 teeth from 545 patients (54.3% men; 45.7% women; mean age: 49.9 +/- 12.1 years) were investigated. In addition to the evaluation of the medical history of the patients, x-rays and a clinical investigation were carried out in order to assess the clinical condition of the crown as well as the restoration types. Of special interest were: carious lesions, composite fillings, amalgam, ceramic or gold crowns and/or bridge restorations. RESULTS: 305 of the examined teeth were located in the mandible and 477 in the maxilla. 26.3% of the teeth were anteriors, 31.2% were premolars and 42.5% were molars. 24.2% of the teeth were restored with metal ceramic crowns, 15.1% were restored with gold cast crowns or served as abutment teeth for bridgework; untreated caries was found in 21.1%, and composite fillings were found in 13.7% of the cases. 23.8% of the front teeth, 26.6% of the premolars and 22.6% of the molars showed a metal ceramic restoration. 21% of all carious defects were found in the maxilla as well as in the mandible. CONCLUSIONS: In addition to the high number of untreated carious lesions, the presence of metal ceramics restorations was significantly higher than other restorations types. Carious lesions are main aetiological factors for endodontic measures, but also ceramic restorations including premature contacts have to be considered as causal factors for pulpal irritations.

Survival rate of endodontically treated teeth in relation to conservative vs post insertion techniques -- a retrospective study.

AIMS AND METHODS: The purpose of this retrospective, non-randomised cohort study was to evaluate the success rate of 775 endodontically treated teeth depending on the restoration type. A total of 508 patients with 775 endodontically treated teeth were examined during at least 12 months. The radiographic controls, time span between root canal filling and definitive restoration, restoration material type, inserted post system type and the occurrence of possible endodontically as well as restorative post-operative complications were recorded. RESULTS: 18.3% of the 775 investigated teeth were incisors and canines, 33.5% were premolars and 48.2% molars. Pre-fabricated and casted metal post systems were used only in 15.6% of the endodontically treated teeth (18.4% incisors and canines, 44.8% premolars, 36.8% molars). 6.6% of the teeth had endodontically related symptoms or severe complications, whereas in 13.2% of the teeth restored with metal posts showed complications, such as root or crown fractures. The Cox-Regression analysis showed that teeth restored with a post system had a statistically significant higher failure rate (p = 0.044) than those which had been restored without posts. CONCLUSIONS: The results showed a high success rate for endodontically treated teeth when the final restoration was placed within a short period of time (two weeks). A higher tooth loss was observed when metal post systems were employed suggesting that precaution is recommended when these types of posts are inserted.

Effect of calcium hydroxide and chlorhexidine based gutta-percha points on gingival fibroblasts and epithelial tumor cells.

AIMS AND METHODS: The aim of the present study was to demonstrate the possible effect of different endodontic calcium hydroxide and chlorhexidine-based gutta-percha points, on two different human cell culture systems. Two different calcium hydroxide (Roeko, Langenau, Germany) and one chlorhexidine (Activ Point/Roeko, Langenau, Germany) gutta-percha points were tested with gingival fibroblasts and epithelial tumor cells over a period of six days (n = 12). Conventional gutta-percha points (VDW, Munich, Germany) and cells that were not exposed to any substances served as controls (n = 12). Study parameters included cell vitality, cell count, protein synthesis and cell proliferation. RESULTS: All tested materials induced cell growth specific alterations. Chlorhexidine-based gutta-percha points showed a significant lower protein synthesis with both, gingival fibroblasts (0.013 +/- 0.009 mg/ml) and epithelial tumor cells (0.07 +/- 0.039 mg/ml), when compared with the controls (p > 0.05). Protein synthesis increase of the epithelial tumor cells (0.581 +/- 0.013 mg/ml, control) was observed with the conventional gutta-percha points (0.688 +/- 0.078 mg/ml) and with both gutta-percha points containing different calcium hydroxide-based formulations (0.776 +/- 0.115 and 0.7 +/- 0.047 mg/ ml). CONCLUSIONS: Under the conditions of this study, chlorhexidine containing gutta-percha points showed the highest effect on cell growth inhibition. No significant differences were observed between the tested material and the two different cell culture types.