Audiological results with Baha in conductive and mixed hearing loss

The level of improvement in the audiological results of Baha(®) users mainly depends on the patient's preoperative hearing thresholds and the type of Baha sound processor used. This investigation shows correlations between the preoperative hearing threshold and postoperative aided thresholds and audiological results in speech understanding in quiet of 84 Baha users with unilateral conductive hearing loss, bilateral conductive hearing loss and bilateral mixed hearing loss. Secondly, speech understanding in noise of 26 Baha users with different Baha sound processors (Compact, Divino, and BP100) is investigated. Linear regression between aided sound field thresholds and bone conduction (BC) thresholds of the better ear shows highest correlation coefficients and the steepest slope. Differences between better BC thresholds and aided sound field thresholds are smallest for mid-frequencies (1 and 2 kHz) and become larger at 0.5 and 4 kHz. For Baha users, the gain in speech recognition in quiet can be expected to lie in the order of magnitude of the gain in their hearing threshold. Compared to its predecessor sound processors Baha(®) Compact and Baha(®) Divino, Baha(®) BP100 improves speech understanding in noise significantly by +0.9 to +4.6 dB signal-to-noise ratio, depending on the setting and the use of directional microphone. For Baha users with unilateral and bilateral conductive hearing loss and bilateral mixed hearing loss, audiological results in aided sound field thresholds can be estimated with the better BC hearing threshold. The benefit in speech understanding in quiet can be expected to be similar to the gain in their sound field hearing threshold. The most recent technology of Baha sound processor improves speech understanding in noise by an order of magnitude that is well perceived by users and which can be very useful in everyday life.

Behaviour of general dental practitioners in Germany regarding posterior restorations with flowable composites

Because the recommendation to use flowables for posterior restorations is still a matter of debate, the objective of this study was to determine in a nationwide survey in Germany how frequently, for what indications, and for what reasons, German dentists use flowable composites in posterior teeth. In addition, the acceptance of a simplified filling technique for posterior restorations using a low stress flowable composite was evaluated. Completed questionnaires from all over Germany were returned by 1,449 dentists resulting in a response rate of 48.5%; 78.6% of whom regularly used flowable composites for posterior restorations. The most frequent indications were cavity lining (80.1%) and small Class I fillings (74.2%). Flowables were less frequently used for small Class II fillings (22.7%) or other indications (13.6%). Most frequent reasons given for the use of flowables in posterior teeth were the prevention of voids (71.7%) and superior adaptation to cavity walls (72.9%), whereas saving time was considered less important (13.8%). Based on the subjective opinion of the dentists the simplified filling technique seemed to deliver advantages compared to the methods used to date particularly with regard to good cavity adaptation and ease of use. In conclusion, resin composites are the standard material type used for posterior restorations by general dental practitioners in Germany and most dentists use flowable composites as liners.

Comparisons of sound processors based on osseointegrated implants in patients with conductive or mixed hearing loss

To compare the patient benefit of the Bone-Anchored Hearing Aid (Baha) Divino and the Baha BP100 sound processors.

Depth of cure of resin composites: is the ISO 4049 method suitable for bulk fill materials?

To evaluate if depth of cure D(ISO) determined by the ISO 4049 method is accurately reflected with bulk fill materials when compared to depth of cure D(new) determined by Vickers microhardness profiles.

Microhardness and marginal adaptation of pre-warmed composites

Objectives: The aim of this study was to examine the effect of pre-warmed composite on the microhardness and marginal adaptation. Methods: Ninety six identical class II cavities were prepared in extracted human molars and filled/cured in three 2 mm increments using a metal matrix. Two composites (Tetric Evo Ceram (IvoclarVivadent) and ELS(Saremco)) were cured with a LED curing unit (Bluephase (IvoclarVivadent)) using curing cycles of 20 and 40 seconds. The composite was used at room temperature or pre-warmed at 54.5ºC (Calset(AdDent)). Twelve teeth were filled for every composite-curing time-composite temperature combination. The teeth were thermocycled (1000 cycles at 5º and 55ºC) and then stored at 37° C for seven days . Dye penetration (basic fuchsine 5% for 8 hours) was measured using a score scale. Knoop microhardness was determined 100, 200, 500, 1000, 1500, 2500, 3500, 4500 and 5500µm from the occlusal surface at a distance of 150 and 1000µm from the metal matrix. The total degree of polymerization of a composite specimen was determined by calculating the area under the hardness curve. Results: Statistical analyses showed no difference in marginal adaptation (p>0.05). Hardness values at 150µm from the matrix were lower than those at 1000µm. There was an increase of the microhardness at the top of each increment and decrease towards the bottom of each increment. Longer curing times resulted in harder composite samples. Multiple linear regression showed that only the curing time (p<0.001) and composite material (p<0.001) had a significant association with the degree of polymerization. The degree of polymerization was not influenced by pre-warming the composite at a temperature of 54.5ºC (p=4.86). Conclusion: Polymerization time can not be reduced by pre-warming the composite on a temperature of 54.5ºC. The marginal adaptation is not compromised by pre-warming the composite.

TAP deficiency syndrome: chronic rhinosinusitis and conductive hearing loss

Nose-ear-throat manifestations of immunodeficiency disorders represent a diagnostic challenge for clinicians as these diseases often constitute the initial sign for connective disorders or autoimmune disease. The history of chronic rhinosinusitis and conductive hearing loss is often non specific. Therefore attention to an HLA class I deficiency must be considered if the disease has not been diagnosed on routine examination. One of the syndromes is due to a defective TAP complex, the peptide transporter complex associated with antigen presentation. Herein, we report two sisters with TAP-deficiency. The treatment of choice for TAP-deficient patients is conservative.

Effect of zirconia surface treatments on the shear strength of zirconia/veneering ceramic composites

Aim of the investigation was to assess the effect of different surface treatments on the bond strength of veneering ceramics to zirconia. In a shear test, the influences of polishing, sandblasting, and silica-coating of the zirconia surface on bonding were assessed with five different veneering ceramics. In addition the effect of liner application was examined. With one veneering ceramic, the impact of regeneration firing of zirconia was also evaluated. Statistical analysis was performed with one-way ANOVA and post hoc Scheffé's test. Failure in every case occurred in the veneering ceramic adjacent to the interface with a thin layer of ceramic remaining on the zirconia surface, indicating that bond strength was higher than the cohesive strength of the veneering ceramic. Shear strength ranged from 23.5 +/- 3.4 MPa to 33.0 +/- 6.8 MPa without explicit correlation to the respective surface treatment. Regeneration firing significantly decreased the shear strength of both polished and sandblasted surfaces. Findings of this study revealed that bonding between veneering ceramics and zirconia might be based on chemical bonds. On this note, sandblasting was not a necessary surface pretreatment to enhance bond strength and that regeneration firing was not recommended.

Self-Absorption and Luminescence Quantum Yields of Dye-Zeolite L Composites

Electronic absorption and fluorescence spectra based on transmission measurements of thin layers obtained from new perylene−zeolite L composites and new dye1,dye2−zeolite L sandwich composites, the latter acting as antenna systems, have been investigated and analyzed. The influence of extra- and intraparticle self-absorption on the spectral shape and fluorescence quantum yield is discussed in detail. Due to its intraparticle origin, self-absorption and re-emission can often not be avoided in organized systems such as dye−zeolite L composites where a high density of chromophores is a prerequisite for obtaining the desired photophysical properties. We show, however, that it can be avoided or at least minimized by preparing dye1,dye2−zeolite L sandwich composites where donors are present in a much larger amount than the acceptors because they act as antenna systems.