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ePaper created 2017-09-12, 09:26:18 | version 1.38.0
| study treatments of teeth with open apical foramen featuring ‘apical closure’ and 36.7 % root extension. However, a direct comparison between the Simon and the present study is not admissible due to the low number of cases, the different observation peri- ods and the non-coordinated interpretations of the evaluation modalities. El Meligy et al. (2006) examined 30 pulpotomy cases (15 Ca(OH)2, 15 MTA), 24 of which were first molars, which suggests a comparison with our study. The following assumptions were applied: no clinical problems, radiographically no apical periodontitis, apexification occurred. 13 calcium hydroxide cases (87 %), but all MTA cases came up to this. The three above mentioned therapy groups of this study achieved an apexification success of totally 85.3 % by means of the formaldehyde-containing N2: 90 % following VitE, 85.7 % following VitA, 57.1 % following conservative root canal treatment of non-vital teeth. The success rate of 57.1 % for non-vital teeth should not be taken too seriously be- cause of the 20.5–93.8 % wide confidence interval due to the small number of cases. The percentaged success referred to the respective teeth as a whole. Another 12 % referred to some molar roots with partly open, partly closed apices. Sheehy and Roberts (1997) comparatively report on the formation of a hard sub- stance barrier after calcium hydroxide application af- ter 5–20 months in 7–100 % of the cases. In contrast, the authors Roberts and Brilliant (1975) considered the interpretation of an X-ray as being unrealistic for determination of a possible apical closure matching the Liang et al. proof of insufficient diagnostics of the periapical X-ray versus digital volume tomography (DVT). 23 teeth were reexamined according to both techniques two years after endodontic treatment. 74 % of periapical radiolucencies could not have been visualized with conservative X-ray and 61 % with DVT. Despite of the diagnostic deficits to be assumed, X-ray in combination with a clinical examination remains the only practical method. An inter pretation bias in this study can be largely eliminated due to the con- sensus finding of the three X-ray evaluators. While in short-term studies with low case numbers extractions are not mentioned, this study counted 19 extractions, 14 of which were allotted to the first mandibular molars. Thus the mandibular molars represented 73.7 % of all extractions with a 50.5 % share in treatments. This relatively high extraction frequency may be due to the fact that these teeth erupt early as the first permanent molars thus having been exposed to tooth-damaging influences for the longest time. Extraction is avoided less in the poste- rior area versus the anterior areas, as in young pa- tients the gap normally closes the natural way with- out orthodontic or prosthodontic treatment. Garcia-Godoy and Murray (2012) made up a survey with hints to deficits in apexification literature. Ac- cording to this survey, 200 case studies on calcium hydroxide had been published. Reports on unfavourable and long-term effects would be missing. One problem of long-term calcium hydroxide dressings would be an alteration of the mechanical dentine character- istics, which could lead to fractures. Long-term stud- ies regarding MTA would be missing. However, for achieving apexification, mineral-trioxide aggregate would be more effective than calcium hydroxide. Also regarding regenerative procedures, only case studies and case series would exist. The ‘blood clot’ generated during this therapy should however have no contact to the inserted sealer, as sealers were not biocompatible and featured a cell-toxic effect. In the present study, pulp tissue, possibly blood as well, had contact to the cell-toxic N2. As the long- term observation showed, this contact had no disad- vantageous effect to the respective teeth. Regarding apexification and apexogenesis, a perennial study rather proved that the success rate was at least equal to MTA and calcium hydroxide. Root fracture, as sus- pected in calcium hydroxide cases, could not have been noticed in any of the cases. One-stage treatment has to be considered as special advantage of N2 ap- plication aiming at apexification, which at the same time is a time- and cost-saving method._ Editorial note: A list of references is available from the publisher. authors Dr Anette Joschko,General Dentist, Cologne, Germany Dr Robert Teeuwen, General Dentist, Geilenkirchen, Germany Prof. Jerome Rotgans, RWTH Aachen University, Medical Faculty, Aachen, Germany contact Dr Robert Teeuwen Berliner Ring 100 52511 Geilenkirchen Germany robteeuwen@t-online.de 14 roots 3 2017