The influence of bone substitute materials on the bone volume after maxillary sinus augmentation: a microcomputerized tomography study

Objectives

This study aims to evaluate the effect of adding bone substitute materials (BSM) to particulated autogenous bone (PAB) on the volume fraction (Vf) of newly formed bone after maxillary sinus augmentation.

Materials and methods

Thirty healthy patients undergoing maxillary sinus augmentation were included. PAB (N?=?10), mixtures of PAB and beta-tricalciumphosphate (PAB/β-TCP) (N?=?10), as well as PAB and β-TCP and hydroxyapatite (PAB/HA/β-TCP) (N?=?10) were randomly used for sinus augmentation. A sample of the graft material was maintained from each patient at time of maxillary sinus augmentation, and Vfs of the PAB and/or BSM in the samples were determined by means of microcomputerized tomography (μ-CT). Five months later, samples of the grafted areas were harvested during implantation using a trephine bur. μ-CT analysis of these samples was performed, and the Vf of bone and BSM were compared with the data obtained 5 months earlier from the original material.

Results

The mean Vf of the bone showed a statistically significant increase (p?<?0.05) in all groups after a healing period of 5 months without statistically significant difference between the groups.

Conclusions

With regard to the increase of bone volume, it is not relevant if PAB is used alone or combined with β-TCP or HA/β-TCP.

Clinical relevance

The amount of PAB and associated donor site morbidity may be reduced by adding BSM for maxillary sinus augmentation.     

Histological evaluation of human intrabony periodontal defects treated with an unsintered nanocrystalline hydroxyapatite paste

Objectives

The aim of the study was to clinically and histologically evaluate the healing of human intrabony defects treated with open flap surgery (OFD) and application of a new, resorbable, fully synthetic, unsintered, nanocrystalline, phase-pure hydroxyapatite (nano-HA).

Materials and methods

Six patients, each of them displaying very advanced intrabony defects around teeth scheduled for extraction due to advanced chronic periodontitis and further prosthodontic considerations, were included in the study. Following local anaesthesia, mucoperiosteal flaps were reflected; the granulation tissue was removed, and the roots were meticulously debrided by hand and ultrasonic instruments. A notch was placed at the most apical extent of the calculus present on the root surface or at the most apical part of the defect (if no calculus was present) in order to serve as a reference for the histological evaluation. Following defect fill with nano-HA, the flaps were sutured by means of mattress sutures to allow primary intention healing. At 7 months after regenerative surgery, the teeth were extracted together with some of their surrounding soft and hard tissues and processed for histological analysis.

Results

The postoperative healing was uneventful in all cases. At 7 months following surgery, mean PPD reduction and mean CAL gain measured 4.0?±?0.8 and 2.5?±?0.8 mm, respectively. The histological analysis revealed a healing predominantly characterized by epithelial downgrowth. Limited formation of new cementum with inserting connective tissue fibers and bone regeneration occurred in three out of the six biopsies (i.e. 0–0.86 and 0–1.33 mm, respectively). Complete resorption of the nano-HA was found in four out of the six biopsies. A few remnants of the graft particles (either surrounded by newly formed mineralized tissue or encapsulated in connective tissue) were found in two out of the six biopsies.

Conclusion

Within their limits, the present results indicate that nano-HA has limited potential to promote periodontal regeneration in human intrabony defects.

Clinical relevance

The clinical outcomes obtained following surgery with OFD?+?nano-HA may not reflect true periodontal regeneration.     

Correlation of Platelet Growth Factor Release in Jawbone Defect Repair – A Study in the Dog Mandible

Background: Platelet concentrate/platelet‐rich plasma (PRP) has been studied extensively in various experimental models and there is some agreement among workers to its early effect in bone regeneration and healing. We have earlier showed in vitro that titanium in whole blood activates the thrombogenic response to a higher degree than PRP and that a fluoridated test surface augmented the effect compared with control. Purpose: We designed this study to evaluate the effect of PRP and whole blood on bone regeneration in a dog implant defect model and, in addition, the effect of a test surface modified in hydrofluoric acid. A correlation attempt between platelet count, release of growth factors, and bone regeneration was made. Materials and Methods: Six dogs were used and simultaneously with the experimental surgery and implant installation, autologous PRP was prepared. Defects were prepared (6 mm in diameter and 5 mm deep), and implants were installed (TiO₂ gritblasted and hydrofluoric acid treated [test] or TiO₂ gritblasted [control], 5 mm in diameter and 9 mm long) in defects filled with either PRP or whole blood. Randomization of sides between PRP and whole blood, and sites for test and control implants were made. Blood samples were collected from PRP and whole blood. The dogs were killed after 5 weeks of healing, and samples with implants and surrounding bone were collected and processed for analysis. Enzyme linked immunosorbent assays were used for detection of growth factors in PRP. Results: The mean increase of platelet count was 424% in PRP. A correlation for platelet counts and transforming growth factor β was found in each dog (r² = 0.857). Approximately 50% of the region of interest (ROI) in the defects was filled with new bone after 5 weeks. No difference could be observed in ROI by using PRP or whole blood in the defects regarding new bone formation, bone in contact with implant, or distance to first bone contact. However, the fluoridated implants exhibited more new bone formation (p = .03) compared with control, regardless of comparing PRP or whole blood, and also displayed a shorter distance from first bone contact to the margin of the bone envelope (p = .05). Conclusions: Platelet concentrate/PRP failed to show more new bone regeneration in a peri‐implant defect model compared with whole blood. Implants treated with hydrofluoric acid displayed higher percentages of bone fill in the defect.     

Variations in the Use of Diagnostic Criteria for Developmental Dysplasia of the Hip

Background

Wide variation exists in reported prevalence estimates and management standards of developmental dysplasia of the hip (DDH). Discrepancies in diagnosticians’ opinions may explain some of this variation.

Questions/purposes

We sought to determine (1) the consistency with which pediatric orthopaedic surgeons rate the importance of diagnostic criteria for DDH, and (2) whether there were geographic differences in how the diagnostic criteria were rated by surgeons.

Methods

One hundred ninety-seven of 220 members of the European Paediatric Orthopaedic Society and 100 of 148 members of the British Society of Children’s Orthopaedic Surgery treating children with DDH participated in this cross-sectional study across 35 countries (15 regions). Each rated 37 items in four domains that specialists previously had identified as the most important features associated with DDH in early infancy. We determined consistency using the intraclass correlation coefficient (ICC; two-way random-effects model) interpreted as poor (0–0.40), acceptable (0.41–0.74), or good (≥ 0.75).

Results

Poor consistency among surgeons was found in rating the 37 diagnostic criteria (ICC, 0.33; 95% CI, 0.24–0.45). Consistency was poor for three domains (patient characteristics/history: ICC, 0.29; 95% CI, 0.16–0.58; ultrasound: ICC, 0.26; 95% CI, 0.14–0.52; radiography: ICC, 0.34; 95% CI, 0.12–0.95) and acceptable for one (clinical examination: ICC, 0.50; 95% CI, 0.33–0.73). Surgeons in particular regions appeared to have a concept of DDH diagnosis that distinguished them from specialists of other regions; consistency in eight regions was greater (ICC ≥ 0.40) than consistency among all 15 regions.

Conclusions

The consistency of specialists in rating diagnostic criteria for DDH was lower than expected, and there was considerable geographic variation in terms of how specialists assigned importance ratings of the diagnostic criteria; these findings are somewhat counterintuitive, given the frequency with which this condition is diagnosed. These inconsistencies could explain, partly, the widely differing prevalence estimates and management standards of DDH.     

Noninvasive visualization of tumor growth in a human colorectal liver metastases xenograft model using bioluminescence in vivo imaging

Background

Bioluminescence imaging (BLI) is an ideal tool for noninvasive, quantitative monitoring of tumor progression/regression in animal models. The effectiveness of different treatment strategies is displayed by an altered intensity of bioluminescence, demonstrating a change of the tumor burden. The aim of this study was to establish a reliable, reproducible colorectal hepatic metastases cancer animal model.

Methods

Cells of the human colon carcinoma cell line HCT-116 Luc^pos expressing the firefly luciferase enzyme gene were used. HCT-116 Luc^pos cells (2.5 × 10⁶) were injected through the portal vein into the liver of immunoincompetent nude mice. BLI was used to analyze intrahepatic tumor burden and growth kinetic.

Results

HCT-116 Luc^pos cells demonstrated a progressive and reproducible growth in the liver after intraportal injection. Four days after injection, the animals were analyzed for tumor growth by BLI, and mice without or too low bioluminescence signals were excluded (between 10% and 20% animals). HCT-116 Luc^pos intrahepatic tumors responded successfully to different dosages (5 and 10 mg/kg) of 5-fluorouracil.

Conclusions

BLI is an important tool with many potential advantages for investigators. The measurement of intrahepatic tumor growth by imaging luciferase activity noninvasively provides valuable information on tumor burden and effectiveness of therapy. Thus, the presented intrahepatic metastases model based on the growth of HCT-116 Luc^pos cells is suitable for in vivo testing of different cancer therapy strategies.     

Single‐Center Experience With Extracorporeal Life Support in 103 Nonpostcardiotomy Patients

Extracorporeal membrane oxygenation (ECMO) has been successfully used to support patients with cardiac arrest failing to respond to conventional cardiopulmonary resuscitation (CPR). Preimplant factors being indicative for success are unknown up to now. The study describes single center experience with special focus on differences between survivors and nonsurvivors. Between 2002 and 2009, 103 patients were supported within the scope of CPR by means of ECMO. Besides primary diagnosis, duration, and outcome, pH, lactate, mean arterial pressure, aspartate aminotransferase, bilirubin, catecholamine dosage, and oxygenation ratio before ECMO, after 2 h, 1 day, and at explantation were analyzed. One hundred three patients (51.2 ± 16 years, 35 women, 68 men) were analyzed. Primary cardiac failure led to CPR in 54%. Duration of support was 4.8 ± 0.6 days. Twenty‐nine (28.1%) patients survived to hospital discharge. On ECMO support, pH, lactate, and mean arterial pressure improved significantly. Catecholamine dosage was significantly reduced after ECMO implantation. Demographic data and primary diagnosis revealed no significant influence on outcome. pH, lactate, creatinine, and bilirubin differed significantly between survivors and nonsurvivors in the course of ECMO support. ECMO support during CPR reliably improves the circulatory and respiratory situation. Considering observed survival critical patient selection is mandatory. Although there are several significant differences between surviving patients and patients with fatal outcome, patient selection turns out to be difficult as clinically relevant factors show only limited predictive value. Future research should focus on better defining a population that may be best of all suited for the use of ECMO support in CPR.