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Purpose: This study aimed to compare the long-term outcomes of two different nonimplant treatments in the bilateral shortened dental arch (SDA).Materials and Methods: In a multicenter randomized controlled clinical trial, patients with complete molar loss in one arch were assigned to one of two different nonimplant treatments. In the partial removable dental prosthesis (PRDP) group, patients were provided with a distal-extension prosthesis retained with precision attachments. In the SDA group, patients were treated according to the SDA concept by preserving or restoring a premolar occlusion.Results: Of the 152 treated patients, 82 reached the 10-year examination independent of their dental or prosthetic status. In the intention-to-treat analysis, the survival rates for tooth loss at 10 years were 0.44 (95% confidence interval [CI]: 0.30 to 0.56) in the PRDP group and 0.52 (95% CI: 0.37 to 0.65) in the SDA group. For tooth loss in the study arch, the survival rates were 0.67 (95% CI: 0.52 to 0.78) in the PRDP group and 0.60 (95% CI: 0.45 to 0.73) in the SDA group. The number of teeth lost was higher than expected. In a multivariate analysis using a multiple Cox regression model, the covariates age (unit: 1 year, Hazard Ratio [HR]: 1.033, P = .03) and DMFT value (unit: 1 tooth, HR: 1.121, P = .03) were significant for time to first tooth loss in the study arch.Conclusion: The results suggest an overestimation of the influence of the prosthetic management of the bilateral SDA. In treatment decisions, patient preferences should be considered with appropriate weight. [ABSTRACT FROM AUTHOR]

Background: Few long‐term studies on treatments in the shortened dental arch (SDA) are available. Objective: The objective of this trial was to analyse the long‐term success of two different treatment concepts. Methods: Patients over 35 years of age with missing molars in one jaw and at least the canine and one premolar present on both sides were eligible. In the partial removable dental prosthesis (PRDP) group (N = 81), molars and missing second premolars were replaced by a precision attachment retained prosthesis. In the SDA group (N = 71), the dental arch ended with the second premolar that had to be present or replaced by a cantilever fixed dental prosthesis. Follow‐up examinations were carried out over 15 years. Results: A comprehensive outcome variable comprised four failure categories for which Kaplan‐Meier survival (success) analyses were conducted. Half of the patients exhibited a continuous preservation of the per protocol prosthetic status that remained totally unaffected by complications for more than 10 years. The event‐free success rates for moderate or worse failure implied a loss of the per protocol prosthetic status. The respective survival rates fell below 50% at 14.2 years in the PRDP group and 14.3 years in the SDA group. In none of the analyses, a significant group difference was found. Conclusions: In patients with an SDA condition, changes in the prosthetic status have to be expected. The affected proportion increases almost linearly from shortly after treatment and comprises the majority after 15 years. The influence of the examined treatments on success appears to be low. [ABSTRACT FROM AUTHOR]

Objective: In vitro studies showed superior impression correctness for one-stage impressions. However, clinical data, especially clinical trials, are lacking in this matter. The aim of the study was to investigate the three-dimensional correctness of impressions for final restorations applying three different impression techniques. Method and Materials: Three impressions each were made from 48 patients with different techniques using metal stock trays. In a randomized order, one-stage putty-wash, two-stage putty-wash, and monophase impressions (respectively, Dimension Penta H and Garant L, Dimension Penta H Quick and Garant L Quick, Impregum Penta; 3M ESPE) were made with either polyvinyl siloxane or polyether materials. The double-cord technique was applied at all abutment teeth. Factors potentially influencing the correctness of the impressions were recorded. The precision of the impressions was three-dimensionally analyzed using the resulting gypsum models. Discrepancies between the impressions were calculated using the one-stage putty-wash impression as reference. Results: Discrepancies between the one-stage puttywash impressions and the monophase impressions are significantly lower compared with two-stage putty-wash impressions. The depth of the most subgingival portion of the preparation margin significantly influences the discrepancies between the impression techniques. Conclusion: In light of the major influence of clinical parameters on impression correctness, one-stage procedures should be favored. These findings support the results of in vitro investigations. [ABSTRACT FROM AUTHOR]

Purpose: The accuracy of dental impression taking is one major factor influencing the fit of crowns and fixed partial dentures. The aim of this study was to determine the accuracy of three-dimensional (3-D) tooth surface and subgingival tooth surface reproduction using three different silicone materials and the two-stage putty-and-wash technique. Materials and Methods: From 24 probands, three impressions each were taken with Express STD Putty/Wash (3M ESPE), Optosil/Xantopren L (Heraeus Kulzer), and an experimental ultralight body/putty material (3M ESPE) in a randomized order. The preliminary impression was cut according to established procedures for the twostage putty-and-wash technique. Master casts were manufactured with a standardized procedure and optically digitized. The 3-D accuracy was analyzed with a computer-aided procedure. The Express STD putty-and-wash impressions were used as a reference. Linear models were used for the statistical analysis. Results: Mean deviations of 27.0 μm and -23.6 μm were found for Optosil/Xantopren L and 26.5 μm and -22.6 μm for the experimental material when analyzing 3-D surface reproduction. The tooth surface (buccal/oral) significantly influenced the accuracy of the surface reproduction. Optosil/Xantopren L showed a more complete reproduction of the subgingival tooth surface than either the experimental or reference materials. Conclusion: The accuracy of the 3-D tooth surface reproduction as well as the reproduction of the subgingival tooth surface was not favorably influenced when the ultralight wash material was used with established cutting procedures for the preliminary impression. [ABSTRACT FROM AUTHOR]

Objectives: Being a secondary outcome in a multicenter randomized controlled trial, the present analysis focused on interdental spacing in the shortened dental arch (SDA). The aim was to evaluate changes in interdental spacing in dependence of two different treatments after an observation period of up to 5 years. Material and methods: Patients were either treated with a partial removable dental prosthesis (PRDP) for molar replacement (PRDP group) or according to the SDA concept aiming at a premolar occlusion (SDA group) in a randomized manner. Interdental spacing in the anterior region was measured with gauges and categorized as '0' (<0.1 mm), '1' (<0.5 mm), '2' (0.5-1 mm), and '3' (>1 mm). The statistical analysis was performed with analysis of variance models followed by linear contrast. Results: Ninety-one patients (SDA n = 41, PRDP n = 50) were included. Changes of interdental spacing were detected in 70.7 % of all cases. A significant difference between the mean score changes was found in the mandible comparing the PRDP group and the SDA group. The respective mean score changes from baseline to 5 years were 0.23 ( SD 0.49) for the PRDP group and 0.02 ( SD 0.30) for the SDA group ( p = 0.023). Conclusions: Major interdental spacing could be observed in neither of the groups. The SDA concept resulted in a slightly better outcome. Clinical relevance: When deciding whether to replace missing molars, the present results give further support to the SDA concept. [ABSTRACT FROM AUTHOR]

Objectives: The use of fast-setting impression materials with different viscosities for the one-stage impression technique demands precise working times when mixing. We examined the effect of varying working time on impression precision in a randomized clinical trial. Materials and methods: Focusing on tooth 46, three impressions were made from each of 96 volunteers, using either a polyether (PE: Impregum Penta H/L DuoSoft Quick, 3 M ESPE) or an addition-curing silicone (AS: Aquasil Ultra LV, Dentsply/DeTrey), one with the manufacturer's recommended working time (used as a reference) and two with altered working times. All stages of the impression-taking were subject to randomization. The three-dimensional precision of the non-standard working time impressions was digitally analyzed compared to the reference impression. Statistical analysis was performed using multivariate models. Results: The mean difference in the position of the lower right first molar (vs. the reference impression) ranged from ±12 μm for PE to +19 and -14 μm for AS. Significantly higher mean values (+62 to −40 μm) were found for AS compared to PE (+21 to −26 μm) in the area of the distal adjacent tooth. Conclusions: Fast-set impression materials offer high precision when used for single tooth restorations as part of a one-stage impression technique, even when the working time (mixing plus application of the light- and heavy-body components) diverges significantly from the manufacturer's recommended protocol. Clinical relevance: Best accuracy was achieved with machine-mixed heavy-body/light-body polyether. Both materials examined met the clinical requirements regarding precision when the teeth were completely syringed with light material. [ABSTRACT FROM AUTHOR]

Background: Various treatment options for the prosthetic treatment of jaws where all molars are lost are under discussion. Besides the placement of implants, two main treatment types can be distinguished: replacement of the missing molars with removable dental prostheses and non-replacement of the molars, i.e. preservation of the shortened dental arch. Evidence is lacking regarding the long-term outcome and the clinical performance of these approaches. High treatment costs and the long time required for the treatment impede respective clinical trials. Methods/design: This 14-center randomized controlled investigator-initiated trial is ongoing. Last patient out will be in 2010. Patients over 35 years of age with all molars missing in one jaw and with at least both canines and one premolar left on each side were eligible. One group received a treatment with removable dental prostheses for molar replacement (treatment A). The other group received a treatment limited to the replacement of all missing anterior and premolar teeth using fixed bridges (treatment B). A pilot trial with 32 patients was carried out. Two hundred and fifteen patients were enrolled in the main trial where 109 patients were randomized for treatment A and 106 for treatment B. The primary outcome measure is further tooth loss during the 5-year follow-up. The secondary outcome measures encompassed clinical, technical and subjective variables. The study is funded by the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG WA 831/2-1, 2-2, 2-3, 2-4, 2-5). Discussion: The particular value of this trial is the adaptation of common design components to the very specific features of complex dental prosthetic treatments. The pilot trial proved to be indispensable because it led to a number of adjustments in the study protocol that considerably improved the practicability. The expected results are of high clinical relevance and will show the efficacy of two common treatment approaches in terms of oral health. An array of secondary outcome measures will deliver valuable supplementary information. If the results can be implemented in the clinical practice, the daily dental care should strongly profit thereof. Trial registration: The trial is registered at ClinicalTrials.gov under ISRCTN68590603 (pilot trial) and ISRCTN97265367 (main trial). [ABSTRACT FROM AUTHOR]

Background: Previous studies have suggested that azithromycin improves lung function in lung transplant recipients with bronchiolitis obliterans syndrome (BOS). However, these studies did not include a non-treated BOS control cohort or perform survival analysis. This study was undertaken to estimate the effect of azithromycin treatment on survival in lung transplant recipients with BOS. Methods: We conducted a retrospective cohort study of consecutive lung transplant recipients who developed BOS between 1999 and 2007. An association between azithromycin treatment and death was assessed using univariate and multivariate time-dependent Cox regression analysis. Results: Of the 178 recipients who developed BOS in our study, 78 did so after 2003 and were treated with azithromycin. The azithromycin-treated and untreated cohorts had similar baseline characteristics. Univariate analysis demonstrated that azithromycin treatment was associated with a survival advantage and this beneficial treatment effect was more pronounced when treatment was initiated during BOS Stage 1. Multivariate analysis demonstrated azithromycin treatment during BOS Stage 1 (adjusted hazard ratio = 0.23, p = 0.01) and absolute forced expiratory volume in 1 second (FEV1) at the time of BOS Stage 1 (adjusted hazard ratio = 0.52, p = 0.003) were both associated with a decreased risk of death. Conclusions: In lung transplant recipients with BOS Stage 1, azithromycin treatment initiated before BOS Stage 2 was independently associated with a significant reduction in the risk of death. This finding supports the need for a randomized, controlled trial to confirm the impact of azithromycin on survival in lung transplant recipients. [Copyright &y& Elsevier]