Removal of fiber posts using conventional versus guided endodontics: a comparative study of dentin loss and complications.

OBJECTIVES: To compare the efficacy of fiber post removal using conventional (CONV) versus guided endodontics (GE) in terms of dentin loss, residual resin material, procedural errors, and working time in vitro. MATERIAL AND METHODS: Ninety human central incisors were root-filled and scanned by micro-computed tomography (CT), then restored with fiber posts and composite. Twenty-four sets of teeth with up to four human maxillary central incisors were fabricated and divided into three groups: conventional post removal by a general dentist (CG) or endodontology specialist (CS) and guided endodontics (GE) by a general dentist, yielding 30 teeth per operator and group. After treatment, the prepared access cavities were volumetrically assessed by micro-CT. Statistical significance was evaluated by one-way analysis of variance followed by post hoc comparisons with Tukey's HSD test and Pearson's chi-squared test for independence. RESULTS: Both CONV and GE resulted in dentin loss and residual resin material. CS resulted in more dentin loss and less residual resin material than CG and GE (p < .05). All groups had some deviations from the original root canal but no perforations. The shortest working time was observed in the GE group. CONCLUSIONS: Compared to the conventional freehand technique, GE resulted in significantly less radicular dentin loss, a few deviations but no perforations. CLINICAL RELEVANCE: Guided endodontics can improve the speed and safety of fiber post removal without root perforation.

Evaluation of ECG-Gated, High-Pitch Thoracoabdominal Angiographies With Dual-Source Photon-Counting Detector Computed Tomography.

PURPOSE: The aim of this study was to evaluate the radiation dose, image quality, and the potential of virtual monoenergetic imaging (VMI) reconstructions of high-pitch computed tomography angiography (CTA) of the thoracoabdominal aorta on a dual-source photon-counting detector-CT (PCD-CT) in comparison with an energy-integrating detector-CT (EID-CT), with a special focus on low-contrast attenuation. METHODS: Consecutive patients being referred for an electrocardiogram (ECG)-gated, high-pitch CTA of the thoracoabdominal aorta prior to transcatheter aortic valve replacement (TAVR), and examined on the PCD-CT, were included in this prospective single-center study. For comparison, a retrospective patient group with ECG-gated, high-pitch CTA examinations of the thoracoabdominal aorta on EID-CT with a comparable scan protocol was matched for gender, body mass index, height, and age. Virtual monoenergetic imaging reconstructions from 40 to 120 keV were performed. Enhancement and noise were measured in 7 vascular segments and the surrounding air as mean and standard deviation of CT values. The radiation dose was noted and signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. Finally, a subgroup analysis was performed, comparing VMI reconstructions from 40 keV to 70 keV in patients with at least a 50% decrease in contrast attenuation between the ascending aorta and femoral arteries. RESULTS: Fifty patients (mean age 77.0±14.5 years; 31 women) were included. The radiation dose was significantly lower on the PCD-CT (4.2±1.4 vs. 7.2±2.2 mGy; p<0.001). With increasing keV, vascular noise, SNR, and CNR decreased. Intravascular attenuation was significantly higher on VMI at levels from 40 to 65, compared with levels of 120 keV (p<0.01 and p<0.005, respectively). On the PCD-CT, SNR was significantly higher in keV levels 40 and 70 (all p<0.001), and CNR was higher at keV levels 40 and 45 (each p<0.001), compared with scans on the EID-CT. At VMI ≤60 keV, image noise was also significantly higher than that in the control group. The subgroup analysis showed a drastically improved diagnostic performance of the low-keV images in patients with low-contrast attenuation. CONCLUSION: The ECG-gated CTA of the thoracoabdominal aorta in high-pitch mode on PCD-CT have significantly lower radiation dose and higher objective image quality than EID-CT. In addition, low-keV VMI can salvage suboptimal contrast studies, further reducing radiation dose by eliminating the need for repeat scans. CLINICAL IMPACT: ECG-gated CT-angiographies of the thoracoabdominal aorta can be acquired with a lower radtiation dose and a better image quality by using a dual-source photon-countinge detector CT. Furthermore, the inherent spectral data offers the possiblity to improve undiagnostic images and thus saves the patient from further radiation and contrast application.

Clinical outcomes following a combined vertical and horizontal alveolar ridge augmentation and two-stage implant placement using either autogenous tooth roots or autogenous bone blocks.

AIM: To assess and compare the short-term clinical outcomes following a combined vertical and horizontal alveolar ridge augmentation and two-stage implant placement using either autogenous tooth roots (TR) or autogenous bone blocks (AB). MATERIALS AND METHODS: A total of n = 27 patients (TR/AB: 13/14) exhibiting n = 31 implants (TR/AB: 14/17) were available for the analysis. Each subject had been allocated to a combined vertical and horizontal alveolar ridge augmentation using either (1) healthy TR (e.g., retained wisdom teeth), or (2) monocortical AB harvested from the retromolar area (i.e. external oblique line). Clinical parameters (e.g., bleeding on probing, BOP; probing pocket depth, PD; mucosal recession, MR) were recorded after a follow-up period of 16.03 ± 4.3 months following implant placement. RESULTS: The survival rates amounted to 100% in both groups. TR and AB grafted sites were associated with similar changes in mean BOP (8.97 ± 27.73%; 11.90 ± 18.97%), PD (0.53 ± 0.49; 0.47 ± 0.67 mm), and MR (0.03 ± 0.13; 0.0 ± 0.02 mm) values. The incidence of peri-implant mucositis and peri-implantitis at the patient level amounted to 15.38% and 0.0% in the TR-, and 28.57% and 7.14% in the AB group. CONCLUSIONS: Both surgical procedures were associated with peri-implant tissue health and stability on the short-term.

Impact of Anxiety During Hospitalization on the Clinical Outcome of Patients With Osteoporotic Thoracolumbar Vertebral Fracture.

STUDY DESIGN: Multicenter prospective cohort study. OBJECTIVES: Anxiety in combination with osteoporotic vertebral compression fractures (OVCFs) of the spine remains understudied. The purpose of this study was to analyze whether anxiety has an impact on the short-term functional outcome of patients with an OVCF. Furthermore, a direct impact of the fracture on the patient's anxiety during hospitalization should be recognized. METHODS: All inpatients with an OVCF of the thoracolumbar spine from 2017 to 2020 were included. Trauma mechanism, analgetic medication, anti-osteoporotic therapy, timed-up-and-go test (TuG), mobility, Barthel index, Oswestry-Disability Index (ODI) and EQ5D-5L were documented.For statistical analysis, the U test, chi-square independence test, Spearman correlation, General Linear Model for repeated measures, Bonferroni analysis and Wilcoxon test were used. The item anxiety/depression of the EQ5D-5L was analyzed to describe the patients' anxiousness. RESULTS: Data from 518 patients from 17 different hospitals were evaluated. Fracture severity showed a significant correlation (r = .087, P = .0496) with anxiety. During the hospital stay, pain medication (P < .001), anti-osteoporotic medication (P < .001), and initiation of surgical therapy (P < .001) were associated with less anxiety. The anxiety of a patient at discharge was negatively related to the functional outcomes at the individual follow-up: TuG (P < .001), Barthel index (P < .001), ODI (P < .001) and EQ5D-5L (P < .001). CONCLUSIONS: Higher anxiety is associated with lower functional outcome after OVCF. The item anxiety/depression of the EQ5D-5L provides an easily accessible, quick and simple tool that can be used to screen for poor outcomes and may also offer the opportunity for a specific anxiety intervention.

Evaluation of run-off computed tomography angiography on a first-generation photon-counting detector CT scanner - Comparison with low-kVp energy-integrating CT.

PURPOSE: To assess the overall imaging performance (radiation dose and image quality) of a photon-counting detector CT (PCD-CT) in comparison with a state-of-the-art energy-integrating detector CT (EID-CT) in run-off CTAs. METHODS: Consecutive patients who underwent run-off CTA on a PCD-CT were included (PCD-CT cohort). A retrospective cohort of patients who had undergone run-off CTA on an EID-CT was matched for gender, body mass index, height, and age (EID-CT cohort). Virtual monoenergetic imaging (VMI) reconstructions for various keV settings (40-120 keV) were generated. CT values and noise were semiautomatically measured for 13 vascular segments of the abdomen, pelvis, and lower extremities. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated for each segment. Subjective image quality was evaluated by two radiologists along the dimensions 'vessel attenuation', 'vessel sharpness', and 'overall image quality' using 5-point Likert scales. RESULTS: Forty patients (age 70.9 ± 9.8 years; 14 women) were included in the PCD-CT cohort and matched with a corresponding number of EID-CT patients. Overall, there was an inverse correlation of signal and noise but also of SNR and CNR with keV levels used for VMI reconstructions. SNR and CNR in the 40 - 60 keV range exceeded EID-CT levels significantly. Subjective image quality was substantially higher at lower keV levels and showed no significant difference to EID-CT. CONCLUSION: Low keV VMI reconstructions of run-off CTA scans on a PCD-CT result in substantially higher SNR and CNR than 80 kVp and 100 kVp EID-CT acquisitions with equal subjective image quality.

Clinical performance of immediately placed and restored progressive-type implants in the esthetic zone: a prospective observational study.

PURPOSE: To assess implant success and survival of immediately placed and restored progressive-type implants in the esthetic zone. MATERIAL AND METHODS: A total of n = 21 patients (21 implants) had received an immediate placement of a tapered, two-part implant with a progressive thread design (PL) for a single tooth replacement in the anterior maxilla. An immediate 'non full-functional loaded' restoration was provided upon adequate primary stability on a final patient-specific abutment (one abutment-one time concept). The final restoration was provided at 12 weeks (baseline). Implant survival and success (e.g. bleeding on probing-BOP, probing pocket depth-PD, mucosal recession-MR, pink esthetic score-PES) as well as patient- reported outcomes (PROM`S) were recorded at 6 and 12 months. RESULTS: An adequate primary implant stability (i.e. insertion torque > 35 Ncm) was obtained at all but one sites. At 12 months, implant survival (n = 20 patients) amounted to 100%. Non-significant changes to baseline were noted for mean BOP (2.5 ± 28.2%), PD (- 0.26 ± 0.73 mm), and MR (0.0 ± 0.4 mm) values. PES values amounted to 12.9 ± 1.14 and 13.2 ± 0.84 at 6 and 12 months. Technical and mechanical complications were not observed. Patients expressed an overall high satisfaction. CONCLUSIONS: The presented immediacy protocol was associated with high survival and success rates on the short-term.

Staged implant placement after defect regeneration using biphasic calcium phosphate materials with different surface topographies in a minipig model.

OBJECTIVE: To assess the influence of biphasic calcium phosphate materials with different surface topographies on bone formation and osseointegration of titanium implants in standardized alveolar ridge defects. MATERIALS AND METHODS: Standardized alveolar ridge defects (6 × 6 mm) were created in the mandible of 8 minipigs and filled with three biphasic calcium phosphate materials (BCP1-3, 90% tricalcium phosphate/10% hydroxyapatite) with different surface properties (micro- and macroporosities) as well as a bovine-derived natural bone mineral (NBM) as a control. At 12 weeks, implants were placed into the augmented defects. After further 8 weeks of healing, dissected blocks were processed for histological analysis (e.g., mineralized (MT), residual bone graft material (BS), bone-to-implant contact (BIC)). RESULTS: All four biomaterials showed well-integrated graft particles and new bone formation within the defect area. MT values were comparable in all groups. BS values were highest in the NBM group (21.25 ± 13.52%) and markedly reduced in the different BCP groups, reaching statistical significance at BCP1-treated sites (9.2 ± 3.28%). All test and control groups investigated revealed comparable and statistically not significant different BIC values, ranging from 73.38 ± 20.5% (BCP2) to 84.11 ± 7.84% (BCP1), respectively. CONCLUSION: All bone graft materials facilitated new bone formation and osseointegration after 12 + 8 weeks of healing.

The dimensions of the facial alveolar bone at tooth sites with local pathologies: a retrospective cone-beam CT analysis.

OBJECTIVE: To assess the impact of various local pathologies on facial alveolar bone dimensions at tooth sites. MATERIALS AND METHODS: Cone-beam computed tomography images of 60 patients were analyzed. Healthy teeth and teeth with local pathologies (i.e., endodontically treated, periodontally diseased teeth, and teeth with periapical lesions) were included. The thickness of the facial alveolar bone was measured at five locations: (1) the bone crest (W0), (2) 25% (W25), (3) 50% (W50), (4) 75% (W75) of the distance from the bone crest to the root apex (A), and (5) in the A region (W100). The results were considered statistically significant at p < 0.0008 (adjustment according to the statistical correction for multiple testing). RESULTS: A total of 1174 teeth (707 healthy and 467 with the local pathologies) were assessed. Periodontally diseased maxillary premolars and anterior teeth in the mandible in the W0 position, as well as maxillary molars in the W25 position, tended to have a lower facial bone thickness when compared to the healthy teeth (0.68 mm vs. 0.84 mm, p = 0.008; 0.47 mm vs. 0.55 mm, p = 0.004; and 1.27 mm vs. 1.72 mm; p = 0.009, respectively). In contrast, the observed tendency pointed towards thicker facial bone wall for the periodontally diseased mandibular anterior teeth in the W50 position (0.74 vs. 0.52, p = 0.001). Healthy maxillary molars tended to display a thicker facial alveolar bone compared to the teeth with local pathologies in the W25, W50, and W75 positions (p = 0.001, p = 0.005, and p = 0.004, respectively). CONCLUSIONS: The present analysis has indicated that local pathologies are commonly associated with a compromised socket morphology. CLINICAL RELEVANCE: The facial bone thickness was particularly reduced at periodontally diseased teeth, which may challenge implant therapy.

Efficacy of autogenous teeth for the reconstruction of alveolar ridge deficiencies: a systematic review.

AIM: The aim of this systematic review was to critically evaluate the currently existing clinical evidence on the efficacy of autogenous teeth (AT) for the reconstruction of alveolar ridge deficiencies. MATERIALS AND METHODS: A search protocol was developed to answer the focused question: "In patients exhibiting alveolar ridge deficiencies and being in need of an implant retained restoration, what is the efficacy of reconstructive procedures employing AT on changes in ridge dimensions compared with control measures?" Uncontrolled studies were also included to assess the overall efficacy of AT for specific procedures. RESULTS: A total of six studies (one randomized, one non-randomized controlled, two observational, one controlled case series, one retrospective) were identified. Two studies used AT for staged lateral augmentation, whereas four studies used AT as a demineralized dentin matrix (AutoBT) for the simultaneous grafting of dehiscence-type defects, vertical augmentation of post-extraction sockets, and lateral/transcrestal sinus floor elevation. The reported clinical outcomes following the application of either AT or AutoBT were within the range of those data noted in the respective control groups. Adverse events were commonly not observed. CONCLUSIONS: The available limited studies involved relatively small patient samples and short follow-up periods but pointed to the potential of AT to serve as an alternative material for the reconstruction of alveolar ridge deficiencies. CLINICAL RELEVANCE: AT appear to be effective in reconstructing alveolar ridge deficiencies.

[Radiological imaging to assess individual cardiovascular risk]. / Radiologische Bildgebung zur Bestimmung des individuellen kardiovaskulären Risikos.

CLINICAL/METHODICAL ISSUE: Radiologic imaging for the assessment of individual cardiovascular risk. STANDARD RADIOLOGICAL METHODS: The correct estimation of the individual cardiovascular risk is prerequisite for the prevention of cardiovascular diseases. Here, extensive evidence is available for coronary calcium scans as well as coronary CT angiography (CTA). METHODICAL INNOVATIONS: Summary of the available evidence for the use of calcium score and coronary CTA. Illustration of the significance of both tests in current guidelines. PERFORMANCE: Both tests have high prognostic value, surpassing a risk-factor based assessment. In comparison with the calcium score, the CTA has higher incremental value. ACHIEVEMENTS: Results from recent trials confirm an improvement of outcomes in symptomatic patients by performing a CTA compared with standard care. PRACTICAL RECOMMENDATIONS: European and US guidelines recommend a calcium score for risk stratification of asymptomatic patients with a low to intermediate risk profile. For symptomatic patients with low to intermediate coronary artery disease pretest probability, a CTA is recommended.

Nonequilibrium Steady-State Transport in Quantum Impurity Models: A Thermofield and Quantum Quench Approach Using Matrix Product States.

The numerical renormalization group (NRG) is tailored to describe interacting impurity models in equilibrium, but it faces limitations for steady-state nonequilibrium, arising, e.g., due to an applied bias voltage. We show that these limitations can be overcome by describing the thermal leads using a thermofield approach, integrating out high energy modes using NRG, and then treating the nonequilibrium dynamics at low energies using a quench protocol, implemented using the time-dependent density matrix renormalization group. This yields quantitatively reliable results for the current (with errors ≲3%) down to the exponentially small energy scales characteristic of impurity models. We present results of benchmark quality for the temperature and magnetic field dependence of the zero-bias conductance peak for the single-impurity Anderson model.

Chylothorax and chylous ascites. Clinical utility of planar scintigraphy and tomographic imaging with SPECT/CT.

UNLABELLED: The aim was to analyze conventional planar scintigraphy and SPECT/CT in patients clinically suspicious for chylothorax or chylous ascites. Lymphoscintigraphy was performed for two reasons: first, to help diagnose chylothorax or -abdomen, by demonstrating diffuse uptake in fluid accumulations, and then secondly, to detect the site of leakage to test the prediction that additional use of SPECT/CT-technique improves upon the diagnostic value of planar lymphoscintigraphy in the baseline detection of thoraco-abdominal lymphatic disorders. PATIENTS, MATERIAL, METHODS: From 7/2008-7/2014 a total of 24 consecutive patients (8 woman, 16 men; age, range 31-79 years) presenting with clinical symptoms suspicious for chylothorax and/or chylous ascites were examined by planar lymphoscintigraphy (n = 26) and additional tomographic SPECT/CT- (n = 22) or SPECT-technique (n = 2). RESULTS: Chylothorax could be scintigraphically confirmed in n = 9, chylous ascites in n = 5 scintigraphies, and excluded in n = 10 patients. In all planar scintigraphy findings of pathological lymph drainage regions (n = 14), SPECT/CT delivered additional relevant information, notably the anatomic localization of the lymphatic leakage. For the baseline detection of thoraco-abdominal lymphatic transport disorders, lymphoscintigraphy showed sensitivity of 88%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 80%. CONCLUSIONS: Our findings show that due to the particular advantages presented by tomographic separation of overlapping sources, SPECT/CT specifies better the anatomical sites, improving the localization of lymphatic leakage in aid of planning surgical re-interventions.

Concentrations of retinol and tocopherols in the milk of cows supplemented with conjugated linoleic acid.

This study was performed to investigate the hypothesis that supplementation of conjugated linoleic acid (CLA) changes the concentrations of retinol and tocopherols in the milk of cows. To investigate this hypothesis, Holstein cows received daily from 3 weeks ante-partum to 14 weeks post-partum either 172 g of a CLA-free rumen-protected control fat (control group, n = 20) or the same amount of a rumen-protected CLA fat, supplying 4.3 g of cis-9, trans-11 CLA and 3.8 g of trans-10, cis-12 CLA per d (CLA group, n = 20). Milk samples (collected at weeks 1, 3, 5, 8 and 11 of lactation) were analysed for retinol, α- and γ-tocopherol concentrations. Milk of cows supplemented with CLA had higher concentrations of retinol (+34%), α-tocopherol (+44%) and γ-tocopherol (+21%) than milk of control cows (p < 0.05). The daily output of these vitamins via milk was also greater in cows of the CLA group than in cows of the control group (+36, 50 and 24% for retinol, α-tocopherol and γ-tocopherol, respectively, p < 0.05). In agreement with higher concentrations of tocopherols, concentrations of thiobarbituric acid-reactive substances, determined in milk of week 5, were lower in cows of the CLA group than in control cows, indicative of a lower susceptibility of milk lipids to peroxidation. Plasma concentrations of retinol and α-tocopherol, determined at 1 and 5 weeks post-partum, were not different between the two groups of cows. In conclusion, this study shows that supplementing dairy cows with a moderate amount of CLA causes an increase of the concentrations of vitamins A and E in the milk and results in an increased output of those vitamins via milk. These effects might be beneficial with respect to the nutritional value of dairy products and the susceptibility of milk fat to oxidative deterioration.

Contrast-induced acute kidney injury after computed tomography prior to transcatheter aortic valve implantation.

AIM: To identify independent predictors of contrast medium-induced acute kidney injury (CI-AKI) after enhanced multidetector-row computed tomography (MDCT) prior to transcatheter aortic valve implantation (TAVI) in high-risk patients. MATERIALS AND METHODS: The present single-centre study analysed retrospectively 361 patients who were assessed using MDCT prior to TAVI. CI-AKI was defined as an increase in serum creatinine (SCr) of ≥ 25% or ≥ 0.5 mg/dl in at least one sample over baseline (24 h before MDCT) and at 24, 48, and 72 h after MDCT. RESULTS: A total of 38 patients (10.5%) experienced CI-AKI. As compared to patients without CI-AKI, they presented more frequently with estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2), (81.6% versus 64.4%, p = 0.045) and tended to receive higher volumes of iodinated contrast media (ICM; 55.3% versus 39%, p = 0.057). There was a significant interaction between baseline eGFR and the amount of intravenous ICM administered (pfor interaction = <0.001) identifying the amount of ICM >90 ml as independent predictive factor of CI-AKI only in patients with baseline eGFR <60 ml/min/1.73m(2) (OR 2.615; 95% CI: 1.21-5.64). CONCLUSION: One in ten elderly patients with aortic stenosis undergoing MDCT to plan a TAVI procedure experienced CI-AKI after intravenous ICM injection. Intravenous administration of <90 ml of ICM reduces this risk in patients with or without pre-existing impaired renal function. However, in the majority of patients renal function recovers before the TAVI procedure.

Bone tissue response to an oily calcium hydroxide suspension in tibial defects. An experimental pilot study in minipigs.

OBJECTIVES: The present study was conducted to evaluate the bone tissue response after the application of an oily calcium hydroxide suspension (OCHS) into defects created in the tibial bone of minipigs. MATERIALS AND METHODS: Standardized defects (2 ccm) were created into the tibia of 4 Goettinger minipigs. Defects in the test group (n = 4) were filled with OCHS (Osteora, DFS-Diamon, Riedenburg, Germany). Defects in the control group (n = 4) were filled with venous blood. Animals were sacrificed after healing periods of 4 and 8 weeks. Tibias were dissected, soft tissues removed and processed for histological analysis. Digital images (×200) were evaluated using the software CellD (Soft Imaging System, Münster, Germany). The following histomorphometrical landmarks were identified: defect size, mineralized tissue, non-mineralized tissue and residual OCHS. RESULTS: Healing was uneventful in all four animals. In the test group, new bone formation was observed in the vicinity of the defect margins whereas the centre of the defect was dominated by non-mineralized tissue. Mean percentages of mineralized tissue after 4 weeks were 23.01% in the test group vs. 43.45% in the control group. The mean value for residual OCHS was 7,11% at 4 weeks. After 8 weeks mean percentages of mineralized tissue were 28.15% in the test group vs. 44.39% in the control group as well as 7.05% for residual OCHS. CONCLUSION: Within the limits of the present pilot study it can be concluded that OCHS did not have a beneficial effect on new bone formation. To prove an osteoinductive potential of OCHS further studies based on a higher number of samples are needed.

Accuracy of peri-implant bone evaluation using cone beam CT, digital intra-oral radiographs and histology.

OBJECTIVES: The present study assesses the accuracy of three-dimensional (3D) cone beam CT (CBCT) and intra-oral radiography (CR) in visualizing peri-implant bone compared with histology. METHODS: 26 titanium dental implants were placed in dog jaws with chronic type vestibular defects. After a healing period of 2 and 8 weeks (n = 12 dogs) the animals were sacrificed. CBCT scans and CR of the specimen were recorded. Dissected blocks were prepared, and histomorphometric analysis was performed. Both modalities were measured twice by two observers and compared with histomorphometry regarding bone levels and thickness around implants as well as length and diameter of implants. RESULTS: Measurements of CBCT correlated well with histomorphometry of the vestibular bone level, oral bone thickness and implant length (all p-values <0.05). Compared with histomorphometry, the mean differences between CBCT and histomorphometry were between 0.06 and 2.61 mm. Mesial bone level (MBL) and distal bone level (DBL) were underestimated by both CR and CBCT. CR and histology measurements were only significantly correlated for implant length measurements. All intraclass correlations were highly significant. CONCLUSIONS: 3D CBCT provides usable information about bone in all dimensions around implants with varying accuracy. CR and CBCT perform similar in assessing MBL and DBL, but, within its limits, the CBCT can assess oral and buccal bone. Metallic artefacts limit the visualization quality of bone around implants and further research could elucidate the value of post-processing algorithms. When information about osseous perforation of implants is needed, CBCT may still provide clinically valuable information.

Short communication: circulating and milk adiponectin change differently during energy deficiency at different stages of lactation in dairy cows.

Adiponectin, one of the most abundant adipokines in circulation, is known for its role in regulation of body metabolism. The aim of this study was to evaluate the effects of a negative energy balance (NEB) at 2 stages of lactation (lactational NEB at the onset of lactation and an induced NEB by feed restriction near 100 d of lactation) on circulating adiponectin concentrations. We also investigated the effect of feed restriction on adiponectin concentrations in milk and the relationships of blood and milk adiponectin with selected plasma or milk variables and with measures of body condition. Plasma adiponectin was measured in 50 multiparous Holstein dairy cows throughout 3 experimental periods [i.e., period 1=3 wk antepartum up to 12 wk postpartum, period 2=3 wk of feed restriction starting at around 100 d in milk with a control (n=25) and feed-restricted group (50% of energy requirements; n=25), and period 3=subsequent realimentation period for 8 wk]. Milk adiponectin was investigated among 21 multiparous cows at wk 2 and wk 12 of period 1 and wk 2 of period 2. Adiponectin concentrations in plasma and skim milk were measured using an in-house ELISA specific for bovine adiponectin. Major changes in circulating adiponectin concentrations were observed during the periparturient period, whereas energy deficiency during established lactation at around 100 d in milk and subsequent refeeding did not affect plasma adiponectin. Together with lower adiponectin concentrations in milk (µg/mL), the reduction in milk yield led to decreased adiponectin secretion via milk (mg/d) at the second week of feed restriction. Irrespective of time and treatment, milk adiponectin represented about 0.002% of total milk protein. Mean adiponectin concentrations in milk (0.61 ± 0.03 µg/mL) were about 92% lower than the mean plasma adiponectin concentrations (32.1 ± 1.0 µg/mL). The proportion of the steady-state plasma adiponectin pool secreted daily via milk was 2.7%. In view of the similar extent of NEB in both periods of energy deficiency, decreasing adiponectin concentrations seems important for accomplishing the adaptation to the rapidly increasing metabolic rates in early lactation, whereas the lipolytic reaction toward feed restriction-induced NEB during established lactation seems to occur largely independent of changes in circulating adiponectin.

Effect of genotype on chemical composition, ruminal degradability and in vitro fermentation characteristics of maize residual plants.

The objective of this study was to determine the changes to residual plant feeding value of early- and late-maturing maize varieties. The influence of the cell wall carbohydrate composition, in terms of neutral and acid detergent fibre (NDF and ADF) content, NDF and dry matter (DM) degradability, and in vitro organic matter digestibility and gas production on the feeding value of a range of maize genotypes, was measured. The different genotypes were allotted into two maturity groups (MG I--early to mid-early: S210-S240; MG II--mid-late to late: S 250-S280) and harvested at four different harvest dates (depending on the DM content of the kernels). The maize varieties of MG I had lower NDF and ADF contents and higher ruminal DM degradability, in vitro digestibility and gas production and thus a higher feeding value than MG II at the same stage of physiological maturity. A strong negative relationship between NDF content and the ruminal DM degradability (r = -0.81) was observed. The data indicate that the early-maturing varieties permit a larger flexibility in harvesting due to a longer period of starch inclusion into the kernel whilst simultaneously maintaining a good supply of rumen-available fibre. Conclusively, the higher feeding value of the early-maturing varieties, based on lower NDF and high DM digestibility, permits more flexibility in the harvesting period over the later-maturing varieties.

Effect of pulverized natural bone mineral on regeneration of three-wall intrabony defects. A preclinical study.

AIMS: The objective of this study is to evaluate the effects of a paste-like bone substitute material with easy handling properties and improved mechanical stability on periodontal regeneration of intrabony defects in dogs. MATERIALS AND METHODS: Mandibular and maxillary first and third premolars were extracted, and three-wall intrabony defects were created on second and fourth premolars. After a healing period of 3 months, acute type defects were filled with a paste-like formulation of deproteinized bovine bone mineral (DBBM) (particle size, 0.125-0.25 mm) in a collagenous carrier matrix (T1), pulverized DBBM (particle size, 0.125-0.25 mm) without the carrier (T2), or Bio-Oss® granules (particle size, 0.25-1.00 mm) as control (C). All defects were covered with a Bio-Gide® membrane. The dogs were sacrificed after 12 weeks, and the specimens were analyzed histologically and histometrically. RESULTS: Postoperative healing of all defects was uneventful, and no histological signs of inflammation were observed in the augmented and gingival regions. New cementum, new periodontal ligament, and new bone were observed in all three groups. The mean vertical bone gain was 3.26 mm (T1), 3.60 mm (T2), and 3.81 mm (C). That of new cementum was 2.25 mm (T1), 3.88 mm (T2), and 3.53 mm (C). The differences did not reach statistical significance. The DBBM particles were both incorporated in new bone and embedded in immature bone marrow. CONCLUSIONS: The results of this preclinical study showed that the 0.125-0.25-mm DBBM particles in a powder or paste formulation resulted in periodontal regeneration comparable to the commercially available DBBM. Osteoconductivity, in particular, was not affected by DBBM size or paste formulation. CLINICAL RELEVANCE: The improved handling properties of the paste-like bone substitute consisting of small DBBM particles embedded in a collagen-based carrier hold promise for clinical applications.