ORCID Profile
0000-0002-6141-1263
Current Organisation
University of Zurich
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Publisher: Wiley
Date: 22-09-2013
DOI: 10.1111/CLR.12255
Abstract: To assess the influence of an activated implant surface and a synthetic graft material in the maxillary sinus in combination with sinus floor elevation on bone-to-implant contact (BIC) as compared to implants with conventional surfaces. In 16 sheep, sinus bone augmentation was performed using a synthetic bone graft material according to the methods described by Haas et al (Clinical Oral Implants Research, 9, 1998, 107 Clinical Oral Implants Research, 13, 2002, 396). Another 16 sheep received a sinus floor elevation procedure without graft material. Using a paired design, in one sinus of each animal, a conventional implant was placed, whereas an implant with activated surface was placed in the other. Eight animals of each group were sacrificed at 12 weeks and the others at 26 weeks after surgery. Histological analysis was performed to analyse BIC. Results were statistically compared at a significance level of P 0.05). For ungrafted sinuses after 26 weeks, no increase in BIC was recorded (12.1% conventional surface, 15.8% activated surface P > 0.05). In grafted sinuses after 26 weeks, mean values increased to 28.7% for conventional and 34.1% for activated implants (P = 0.014 P = 0.015). However, only BIC of the latter was statistically significantly higher compared with ungrafted sinuses (P = 0.038). After 12 weeks of healing, neither grafting nor implant type seemed to influence BIC. Use of an activated implant surface did not increase BIC when compared with a conventional implant. The synthetic graft seemed to improve BIC values after 26 weeks.
Publisher: Elsevier BV
Date: 04-2010
DOI: 10.1016/J.JOEN.2009.12.020
Abstract: This study evaluated the prepared surface areas of oval-shaped canals in distal roots of mandibular molars using four different instrumentation techniques. Teeth were prescanned and reconstructed using micro-computed tomography (MCT) scans at low resolution (68 microm). Forty-eight molars with ribbon-shaped/oval distal root canals were selected and randomly assigned to four groups. Distal canals (n = 12 each) were prepared by circumferential filing using Hedström files to apical size #40 (group H/CF) with ProTaper nickel-titanium rotaries to finishing file 4 (F4) considering the distal canal as 1 canal (group PT/1) ProTaper to F4 considering buccal and oral aspects of the distal canal as 2 in idual canals (group PT/2) ProTaper to F4 in a circumferential filing motion (PT/CF). Before and after shaping, teeth were evaluated using MCT at 34-microm resolution. The percentage of prepared surface was assessed for the full canal length and the apical 4 mm. Statistical analysis was performed using analysis of variance and Bonferroni/Dunn multiple comparisons. Preoperatively, canal anatomy was statistically similar among the groups (p = 0.56). Mean (+/- standard deviation) untreated areas ranged from 59.6% (+/-14.9, group PT/2) to 79.9% (+/-10.3, PT/1) for the total canal length and 65.2% to 74.7% for the apical canal portion, respectively. Canals in group PT/1 had greater untreated surface areas (p < 0.01) than groups PT/2 and PT/CF. Among all groups, amounts of treated surface areas were statistically similar in the apical 4 mm. Preparations of oval-shaped root canals in mandibular molars left a variable portion of surface area unprepared regardless of the instrumentation technique used. However, considering oval canals as two separate entities during preparation appeared to be beneficial in increasing overall prepared surface.
Publisher: S. Karger AG
Date: 2008
DOI: 10.1159/000128559
Abstract: The aim of this study was to compare cross-sectional nanohardness, measured using an ultra-microindentation system, with mineral content, from transversal microradiography, of artificial enamel caries lesions. Sections (85 ± 10 µm) from 16 bovine enamel s les with artificial caries were prepared. The mineral content and cross-sectional nanohardness at known depths from the surface were compared. Both methods showed lesion profiles with a surface layer. The determination of nanohardness seems limited to lesions with a mineral content vol%. There was a moderate linear relationship between mineral content and the square root of nanohardness (R sup /sup = 0.81). It was concluded that the conversion of cross-sectional hardness into mineral content remains questionable and cannot be recommended.
No related grants have been discovered for Thomas Attin.