Functional quality of molar crown occlusal surfaces in the different design modes of Cerec 2.

The goal of the present study was to objectify whether the design modes of "Correlation", "Function", and "Extrapolation" of the Cerec 2 system are suitable for generating a functionally perfect occlusal surface of a first mandibular molar crown. For this purpose, an occlusal surface was waxed up according to the biomechanical concept of MH Polz, and this served as the reference occlusal surface. Four different Cerec 2 comparison crowns (produced in the laboratory, Extrapolation mode, Correlation mode, Function mode) were produced and the positions of the cusps were measured. It was shown that the Correlation mode delivers the most accurate results, and the manually produced occlusal surface also showed good results. The occlusal surfaces of the crowns produced according to the Extrapolation and Function mode were clearly inferior.

The effect of three different periodontal pre-treatment procedures on the success of telescopic removable partial dentures.

In this prospective study, 120 teeth consisting of maxillary and mandibular canines and premolars were divided into three groups each containing 40 teeth. The teeth were assigned randomly in quadrants to three different periodontal treatment protocols. The first group was treated with professional prophylaxis only. The second group received additional deep scaling. With the third group, additional surgical periodontal flap surgery and scaling was performed. Both papillary bleeding index (PBI) and probing depth (PD) were evaluated before, during and after treatment. During the subsequent prosthetic treatment phase all teeth were then used as telescope abutments supporting a removable prosthesis. The documentation of the attachment level (AL) was then used as a clinical parameter. One year after the incorporation of telescopic removable partial dentures (RPDs), PD, PBI and AL were again evaluated. The resulting periodontal parameters were compared between the different groups using the general linear model (GLM) repeated measures and the Kruskal-Wallis test for non-parametric variables. Differences within the three treatment groups were determined using the t-test, e.g. the Wilcoxon test for dependent variables (P < 0.05). A significant decrease in inflammatory indices (PBI) was found for all types of periodontal treatment (P < 0.03 for all groups). Additionally, the reduction in PD was significant for all of the three groups (P < 0.001 for all groups). The greatest reduction in PD was observed in the group in which a surgical approach was used. Evaluation of the attachment level after the incorporation of the telescopic RPDs showed that tooth position did not influence the periodontal prognosis and that the use of telescopic RPDs exerted no ascertainable negative influence on the periodontium of the abutment teeth.

A comparison of the muscular relaxation effect of TENS and EMG-biofeedback in patients with bruxism.

This study investigated effects of electromyographic (EMG) biofeedback (BFB) and transcutaneous electrical neuromuscular stimulation (TENS) on the EMG activity of the masticatory muscles and skin conductance level (SCL) of patients, suffering from myofacial pain syndrome. In the course of the investigation, EMG activity as well as the SCL was measured after a 20 min BFB or, respectively, after a myomonitor session in 20 patients and pre- and post-treatment values were compared. Results showed tendencies of decreased mean-EMG levels for both groups after the treatment sessions, with higher EMG values for the myomonitor group. There was no indication of a significant decrease in mean EMG levels over the sessions. Furthermore, an increase of the SCL during the period of treatment was observed for both groups in session I and II, while session III produced nearly stable values. No existing correlations for changes in SCL and EMG-activity could be established.

Comparison of the transfer precision of three different impression materials in combination with transfer caps for the Frialit-2 system.

Transfer of the precise position of implants to a master cast is a prerequisite for accurate and passive fit of the superstructure. Implants lack the mobility of natural teeth and, therefore, inaccurate frameworks result in stress within the mechanical parts and the implant-bone interface. Various impression methods have been described to achieve accurate reproduction of the intra-oral relation of the implants. The aim of this experimental study was to compare three different impression materials (polyether, polyvinyl siloxane, hydrocolloid) with the Frialit(R)-2 system and with the indirect technique. In addition, the use of transfer caps (TCs) to improve transfer precision was tested with all three materials. All measurements were performed using a three-dimensional (3D) co-ordinate measuring machine that is capable of locating points in space and calculating the relative distortions as angles of tilt (rot-XY, rot-XZ, rot-YZ) and 3D displacement. The results suggest that addition-silicone (a-silicone) and polyether are the materials of choice for implant transfer procedures. The use of TCs resulted in a significantly reduced rotation in the XY-plane but did not improve the absolute 3D displacement. A-silicone with the use of TCs proved to be most precise. Comparison between polyether and polyvinyl siloxane showed significant differences in the XY-rotation and the 3D displacement in favour of the silicone. Because the mean distortions between the original model and the master casts were about 100 microm, absolutely precise fit may be unattainable owing to the physical properties of the materials. Further studies will have to evaluate the amount of tolerable stress at the implant-bone interface.

Retrospective analysis of Frialit-2 implants in the augmented sinus.

The aim of the present study was to investigate clinical and radiographic data of patients treated with implants in the posterior maxilla in combination with sinus augmentation. Study parameters included Periotest values, radiographic analysis, and survival/success rates up to 5 years. Clinical and radiographic criteria resulted in a success rate of 92.7% for sinus implants. Radiographically, the sinus implants showed a mean coronal bone loss of 0.5 mm at 6 months and 1.2 mm at 48 months. The results showed stable periimplant parameters for sinus implants during the observation period of 5 years. The success rates showed no significant differences regarding different implant-supported treatment options for the posterior maxillary region.

"Phronesis" on tour: cultural adaptability of Aristotelian ethical notions.

How might bioethics take account of cultural diversity? Can practical wisdom of an Aristotelian sort be applied across cultures? After showing that practical wisdom involves both intellectual cleverness and moral virtue, it is argued that both these components have universality. Hence practical wisdom must be universal as well. Hellenic ethical thought neither depended on outdated theoretical notions nor limited itself to the Greek world, but was in fact developed with constant awareness of cultural differences, so it arguably works as well in other times and places when formulated. Even the eudaemonistic setting for practical wisdom is unproblematic.

Residual dentin thickness after 1.2-mm shoulder preparation for Cerec crowns.

Since the introduction of crown software for Cerec, it has been possible to produce full-ceramic crown restorations. Despite the excellent material quality of industrially made ceramic blocks and the good clinical long-term success of these ceramics in inlay- and onlay preparations, extended preparation with high loss of dental tissue is incident to crown restorations, which may endanger the vitality of the respective tooth. The aim of this experimental study was to determine the residual dentin thickness after preparation of an extended circular shoulder in the molar and premolar region. On extracted human molars and premolars, 1.2-mm-wide circular shoulders with rounded inner edges were prepared, and the thickness of the residual dentin wall was measured under a microscope. Using this preparation method, it was found that only the group of maxillary molars showed an average residual dentin thickness of more than 0.7 mm.

Guided bone regeneration with barrier membranes--a clinical and radiographic follow-up study after 24 months.

The present follow-up study evaluated clinical and radiographic parameters of dental implants placed with simultaneous guided bone regeneration with expanded polytetrafluoroethylene (e-PTFE) membranes. All implants were functioning well 24 months after insertion. In all, 63 patients with a total of 91 e-PTFE-augmented implants were integrated in a regular maintenance protocol. Modified periodontal data of 85 implants in 59 patients were recorded at 24 months and indicated no difference to implants placed in sufficient pristine bone. The mean plaque score (mplI) was 0.29, 74% of the sites showed no plaque. The sulcular probing depth ranged from 1 to 7 mm with a mean of 2.6 mm (SD +/- 0.8). Of the sites 96.5% were < or = 4 mm deep, in 49% of them probing resulted in bleeding. Periotest values 6 and 24 months (mean: -3.4 and -3.4) after placement revealed stable peri-implant conditions and sustained osseointegration. The radiographic evaluation performed 6, 12 and 24 months post insertion yielded a mean bone loss of 0.93, 1.36 and 1.51 mm ranging from 0 to 4 mm. The short-term results of our clinical study demonstrated stable peri-implant conditions 2 years after membrane-protected osseous regeneration. The newly formed bone seemed to be able to withstand functional loading in a predictable manner after 18 months.

Secretoneurin, a novel neuropeptide, in the human dental pulp.

Secretoneurin is a neuropeptide that is stored in and released from primary afferent neurones. By radioimmunoassay and immunohistochemistry, secretoneurin was here demonstrated in the human dental pulp and localized in varicose nerve fibres that were frequently associated with blood vessels. No significant correlation was found between the levels of immunoreactive secretoneurin and immunoreactive calcitonin-gene related peptide. The results suggest that primary afferent neurones of the human dental pulp contain secretoneurin, which may influence local inflammatory responses if it is released together with other neuropeptides.