Tissue engineering in dentistry

Objectives

of this review is to inform practitioners with the most updated information on tissue engineering and its potential applications in dentistry.

Data

The authors used “PUBMED” to find relevant literature written in English and published from the beginning of tissue engineering until today. A combination of keywords was used as the search terms e.g., “tissue engineering”, “approaches”, “strategies” “dentistry”, “dental stem cells”, “dentino-pulp complex”, “guided tissue regeneration”, “whole tooth”, “TMJ”, “condyle”, “salivary glands”, and “oral mucosa”.

Sources

Abstracts and full text articles were used to identify causes of craniofacial tissue loss, different approaches for craniofacial reconstructions, how the tissue engineering emerges, different strategies of tissue engineering, biomaterials employed for this purpose, the major attempts to engineer different dental structures, finally challenges and future of tissue engineering in dentistry.

Study selection

Only those articles that dealt with the tissue engineering in dentistry were selected.

Conclusions

There have been a recent surge in guided tissue engineering methods to manage periodontal diseases beyond the traditional approaches. However, the predictable reconstruction of the innate organisation and function of whole teeth as well as their periodontal structures remains challenging. Despite some limited progress and minor successes, there remain distinct and important challenges in the development of reproducible and clinically safe approaches for oral tissue repair and regeneration. Clearly, there is a convincing body of evidence which confirms the need for this type of treatment, and public health data worldwide indicates a more than adequate patient resource. The future of these therapies involving more biological approaches and the use of dental tissue stem cells is promising and advancing. Also there may be a significant interest of their application and wider potential to treat disorders beyond the craniofacial region.

Clinical Significance

Considering the interests of the patients who could possibly be helped by applying stem cell-based therapies should be carefully assessed against current ethical concerns regarding the moral status of the early embryo.     

Advancing Biomarker Development Through Convergent Engagement: Summary Report of the 2nd International Danube Symposium on Biomarker Development,Molecular Imaging and Applied Diagnostics; March 14–16, 2018; Vienna,Austria

Molecular Imaging and Biology - Here, we report on the outcome of the 2nd International Danube Symposium on advanced biomarker development that was held in Vienna, Austria, in early 2018. During...     

What Is the Risk of Reactivation in Patients with Resolved and Past HBV Infection During Immunosuppressive Therapy If HBV-DNA Negative before Treatment?

BackgroundReactivation of Hepatitis B (HBVr) related to immunosuppressive drug therapy (ISDT) in patients with resolved and past infection is a challenging entity. The number of prospective long-term studies is limited.MethodsTwo groups of patients with resolved and past HBV infection were analyzed prospectively. The patients were further categorized as 266 patients receiving ISDT (group 1) and 246 patients receiving antineoplastic therapy (group 2).ResultsWe did not detect any cases of HBVr among 108 patients receiving rituximab (71 of which were anti-HBc positive only), 111 patients receiving tumor necrosis factor inhibitors (66 of which were anti-HBc positive only), and 42 patients receiving high-dose glucocorticoids for more than 4 weeks (24 of which were anti-HBc positive only) during a mean follow-up time of more than 24 months. Subgroup analysis of the anti-HBs (+) patients showed that in group A (anti-HBs >1000 mIU/mL) the antibody levels did not change; in group B (anti-HBs between 100 and 1000 mIU/mL) the antibody levels changed non-significantly (P = .25), and in Group C (anti-HBs between 0 and 100 mIU/mL) the antibody levels declined significantly (P = .002). Furthermore, 16 patients in Group C had an anti-HBs loss during follow-up, but no HBVr was detected.ConclusionThe risk of HBVr by immunosuppressive therapy in this group may be lower than that suspected in the literature and anti-HBs levels may not seem to correlate with the risk of reactivation.     

Development of remineralizing, antibacterial dental materials

Light curable methacrylate dental monomers containing reactive calcium phosphate filler (monocalcium phosphate monohydrate (MCPM) with particle diameter of 29 or 90 μm) and β-tricalcium phosphate (β-TCP) at 1:1 weight ratio in a powder:liquid ratio (PLR) of 1:1 or 3:1 and chlorhexidine diacetate (0 or 5 wt.%), were investigated. Upon light exposure, approximately 90% monomer conversion was gained irrespective of the formulation. Increasing the PLR promoted water sorption by the set material, induced expansion and enhanced calcium, phosphate and chlorhexidine release. Concomitantly, a decline in compressive and biaxial flexural strengths occurred. With a reduction in MCPM particle diameter, however, calcium and phosphate release was reduced and less deterioration in strength observed. After 24 h, the remaining MCPM had reacted with water and β-TCP, forming, within the set materials, brushite of lower solubility. This provided a novel means to control water sorption, component release and strength properties. Measurable chlorhexidine release was observed for 6 weeks. Both diffusion rate and total percentage of chlorhexidine release decreased with lowering PLR or by adding buffer to the storage solutions. Higher chlorhexidine release was associated with reduced bacterial growth on agar plates and in a biofilm fermenter. In cell growth media, brushite and hydroxyapatite crystals precipitated on the composite material surfaces. Cells spread on both these crystals and the exposed polymer composite surfaces, indicating their cell compatibility. These formulations could be suitable antibacterial, biocompatible and remineralizing dental adhesives/liners.     

Ancient nigella seeds from Boyalı Höyük in north-central Turkey

Aim of the study

The seeds of nigella (black cumin) (Nigella sativa L.) have been widely used as a natural remedy, either alone or in combination with bee products, for the treatment of many acute as well as chronic conditions for centuries, especially in the Middle East and Southeast Asia. In consideration of potential utilization, in recent years the seeds have been extensively studied in terms of pharmacological effects. It has been shown that the seeds have significant effects on multiple biological systems. In addition, the protective roles of the seeds with bee products (honey and wax) have been recently proved.This study reports the palaeoethnobotanical find of nigella seeds recovered in a pilgrim flask from the Old Hittite Period level of Boyal? Höyük (Mound), dating from around 1650 BC, in north-central Turkey. The study also deals with a comparison between the chemical properties of the Boyal? Höyük nigella seeds (ancient seeds) and those of modern nigella seeds. The results of chemical analysis of the debris found in the pilgrim flask to test the presence of bee product are also presented here.

Materials and methods

All macro-remains found in the pilgrim flask were first examined under a zoom stereomicroscope for specific determination and all were identified as nigella seeds using the reference collection of modern seeds. Ethyl alcohol and dichloromethane (Aldrich, Buch-Switzerland) were used for the extraction of the ancient seeds and modern nigella seeds to trace both polar and non-polar chemical compounds by a Gas Chromatography–Mass Spectrometer (GC–MS) system. Characterization of the chemical compounds in propolis extracts was also made by GC–MS.

Results

The GC–MS chromatograms showed that the ancient and modern seed samples were similar in essential oil acids. Many organic compounds of bee products, such as wax and phenolic antioxidants, were also detected in the container.

Conclusion

The results of this study indicated that the Hittite pilgrim flask contained a pure cache of nigella seeds mixed with bee products, wax and propolis. There has been no direct archaeological evidence for medicinal use of nigella seeds with bee products by the inhabitants of Boyal? Höyük or the Hittities so far. However, in view of the folkloric use of nigella seeds in combination with bee products for treatments of disorders and promotion of health, it is thought that the Boyal? Höyük material would represent a remedy used by the Hittites in Anatolia about 3600 years ago.     

The accuracy of ultrasound evaluation in foot and ankle trauma

ObjectivesFoot and ankle injuries that result in sprains or fractures are commonly encountered at the emergency department. The purpose of the present study is to find out the accuracy of ultrasound (US) scanning in injuries in the aforementioned areas.MethodsOttawa Ankle Rules–positive patients older than 16 years who presented to the emergency department with foot or ankle injuries were eligible. For all patients, US evaluation of the whole foot and ankle was performed by an emergency physician before radiographic imaging. All radiographic images were evaluated by an orthopedic specialist and compared with the interpretations of the US.ResultsOne hundred thirty-one patients were included in the study. Radiographic evaluation enabled the determination of fractures in 20 patients, and all of these were identified with US imaging. Moreover, US evaluation radiographically detected a silent ankle fracture in 1 patient. The sensitivity of US scanning in detecting fractures was 100% (95% confidence interval [CI], 83.8-100), the specificity was 99.1% (95% CI, 95-99.8), the positive predictive value was 95.2% (95% CI, 89.6-98), and the negative predictive value was 100% (95% CI, 96.4-100), respectively. The most common fractures were detected at the lateral malleolus and at the basis of the fifth metatarsal.ConclusionsUltrasound imaging permits the evaluation of foot and ankle fractures. Because it is a highly sensitive technique, US can be performed in the emergency department with confidence.