Henrik Løvschall

Amelogenesis imperfecta a systematic literature review of associated dental and oro-facial abnormalities and their impact on patients

Objective. Amelogenesis imperfecta (AI) is a disease primarily affecting amelogenesis, but other aberrations have been reported. The purposes of this review were: (1) to identify other anomalies associated with AI, and (2) to describe the impact of the disease and its associated conditions on the oral health-related quality of life of patients, and the economic consequences. Material and methods. A literature search was conducted in the following databases: PubMed, EMBASE, Bibliotek.dk, The Cochrane Library, Web of Science, and OMIM, supplemented by a search for selected authors. Based on titles and abstracts, 137 papers were identified. Results. Most articles were case reports or case series with few cases. Aberrations were reported in the eruption process, in the morphology of the crown, in the pulp-dentine organ, and in the number of teeth. Gingival conditions and oral hygiene were usually reported to be poor, and calculus was a common finding. Open bite was the most commonly reported malocclusion. A negative impact on patients’ oral health-related quality of life was described, but information was scarce. No information was found on the economic impact. Conclusions. A number of aberrations associated with AI have been reported, but not sufficiently systematic to allow for a secondary analysis and synthesis of the findings. The impact on patients in terms of reduced quality of life and economic burden needs to be studied.

Hypocalcified type of amelogenesis imperfecta in a large family: clinical, radiographic, and histological findings, associated dento-facial anomalies, and resulting treatment load

Objective. The purpose of this study was to report on the clinical, radiographic, and histological dental findings and the resulting treatment load in a five-generation family with amelogenesis imperfecta (AI). Material and methods. Thirteen affected and 15 unaffected individuals were examined clinically and radiographically. In addition, four exfoliated deciduous teeth were examined by scanning electron microscopy and microradiography. Results. The mode of inheritance of AI was autosomal-dominant. At eruption, most of the tooth enamel was yellow, lacking translucency, and prone to gradual loss in subjects with AI. Post-eruptive breakdown of enamel was extensive in accordance with the histological observations of hypomineralized and porous enamel. Extensive enamel loss and discoloration were observed in older affected individuals. The treatment need had been extensive: 76.2% of the total number of teeth present in affected individuals had been treated with partial or full coverage compared to 1.7% of the teeth in unaffected relatives. Unaffected individuals had more endodontically treated teeth than AI-affected relatives. Adjunctive findings, e.g. tooth agenesis, tooth impaction, pulp stones, enlarged follicular space, and taurodontism, were rare in both groups. Conclusions. Affected family members had the hypocalcified type of AI, which is characterized by severe hypomineralization, extensive post-eruptive loss, and discoloration of the enamel. Adjunctive findings were rare. Individuals with the hypocalcified type of AI have an extensive restorative treatment load compared to unaffected relatives.

Test of Critical Steps towards a Combined Cell and Gene Therapy Approach for the Treatment of Duchenne Muscular Dystrophy

Background: Therapies for muscular dystrophies remain a major challenge in spite of advanced strategies using either cell or gene therapy. We here propose a combined approach of cell and gene therapy. As gene delivery vehicles with specific homing potential we have chosen mesoangioblasts which are stem cells with mesodermal potential. This study specifically tests the maintenance of myogenic properties by EGFP-transduced mesoangioblasts and their ability to function as retroviral packaging cells in transient culture. Methods: Mesoangioblasts transduced to express EGFP (EGFP-MA) were tested for myogenic properties in coculture. Survival and in situ myogenic differentiation were studied upon injection into degenerating M. gastrocnemius of athymic mice. In situ participation in muscle regeneration was confirmed on cryo-sections using EGFP fluorescence as marker. The ability of mesoangioblasts to serve as retroviral packaging cells was tested using the murine cell line NIH 3T3 fibroblasts as recipients in vitro and evaluation of transduction by fluorescence microscopy. Results: EGFP-MA retained the ability to differentiate into skeletal muscle myotubes upon co-culture with C2C12 cells. In vivo, mouse M. gastrocnemius exhibited EGFP-signals within and at the basal lamina of skeletal muscle fibers 3, 10 and 24 days after injection of EGFP-MA. In culture, target cells could be transduced with EGFPencoding virions produced by mesoangioblasts. Conclusions: Introduction of a retroviral vector into mesoangioblasts did not interfere with the myogenic properties of mesoangioblasts in culture or in vivo. Mesoangioblasts are able to function as retroviral packaging cells in vitro. While a possible therapeutic application of this new gene delivery system will require further detailed analysis of the long-term efficiency and the quantitative aspects of the method, our proof of principle study shows that the approach is feasible.

Apatite precipitation on a novel fast-setting calcium silicate cement containing fluoride

Abstract Aim: Calcium silicate cements are widely used in endodontics. Novel fast-setting calcium silicate cement with fluoride (Protooth) has been developed for potential applications in teeth crowns including cavity lining and cementation. Objective: To evaluate the surface apatite-forming ability of Protooth compositions as a function of fluoride content and immersion time in phosphate-buffered saline (PBS). Material and methods: Three cement compositions were tested: Protooth (3.5% fluoride and 10% radiocontrast), ultrafast Protooth (3.5% fluoride and 20% radiocontrast), and high fluoride Protooth (15% fluoride and 25% radiocontrast). Powders were cap-mixed with liquid, filled to the molds and immersed in PBS. Scanning electron microscopy, energy dispersive X-ray analysis, and Raman spectroscopy were used to characterize the precipitations morphology and composition after 1, 7, 28, and 56 days. Apatite/belite Raman peak height indicated the apatite thickness. Results: Spherical calcium phosphate precipitations with acicular crystallites were formed after 1-day immersion in PBS and Raman spectra disclosed the phosphate band at 965 cm−1, supporting the apatite formation over Protooth compositions. The apatite deposition continued and more voluminous precipitations were observed after 56 days over the surface of all cements. Raman bands suggested the formation of β-type carbonated apatite over Protooth compositions. High fluoride Protooth showed the most compact deposition with significantly higher apatite/belite ratio compared to Protooth and ultrafast Protooth after 28 and 56 days. Conclusions: Calcium phosphate precipitations (apatite) were formed over Protooth compositions after immersion in PBS with increasing apatite formation as a function of time. High fluoride Protooth exhibited thicker apatite deposition.

Macrophage-mediated nanoparticle delivery to the periodontal lesions in established murine model via Pg-LPS induction

We established a murine periodontitis model by local injection of lipopolysaccharide of Porphyromonas gingivalis (Pg-LPS) into the gingival sulcus of mandibular left incisor four times with 48-h interval. The histological examination of the periodontal tissues demonstrated that significant loss of periodontal bone and ligaments was observed in the lesion side with abundant inflammatory cell infiltration. Two days after the last injection, Cy5-labelled siRNA/chitosan particles were injected intraperitoneally (ip). The chitosan/siRNA particles were taken up by peritoneal macrophages, which subsequently migrated to the inflamed gingival area evaluated by in vivo imaging. The localization of macrophages in the inflamed region was further confirmed by immunofluorescent staining. The present report demonstrates that intragingival injection of Pg-LPS can be used to create an experimental model of periodontal inflammation in mice and that recruitment of macrophages with chitosan/siRNA nanoparticles to the inflamed area opens the possibility of an RNAi-based therapeutic approach using chitosan as a carrier in periodontitis.

In vitro cytotoxic evaluation of novel fast-setting calcium silicate cement compositions and dental materials using colorimetric methyl-thiazolyl-tetrazolium assay

A novel fast-setting calcium silicate cement with fluoride (CSC) has been developed for potential application in tooth crowns. This study compared the cytotoxicity of CSC compositions and a variety of dental materials. We tested CSC compositions (Protooth), MTA, Biodentine, Ketac Molar, Fuji II LC, Vitrebond, DeTrey Zinc, Dycal, and IRM, DMEM (negative control) and 1% NaOCl (positive control). After setting of cements for 24 h, specimens were immersed in DMEM for 24 h to obtain material elutes. The elutes were serially diluted in serum-free DMEM to obtain three dilutions. L929 mouse fibroblast cells (1 × 104 cells per well) were treated for 24 h with elute dilutions (n = 3). Cytotoxicity was determined using methyl-thiazolyl-tetrazolium assay in triplicate. CSC compositions, MTA, and Biodentine showed no significant reduction in cell viability compared to DMEM. There was no significant difference in cell viability, at any of three dilutions, between CSC compositions and either MTA or Biodentine. Cytotoxicity was significantly lower for CSC compositions than for Vitrebond, DeTrey Zinc, Dycal, IRM, and 1% NaOCl, at all three dilutions, and undiluted Fuji II LC elute. In contrast to resin-modified glass ionomers, zinc phosphate cements, Dycal, and IRM, the CSC compositions showed no cytotoxic potential.

Survival of Composite Resin Restorations of severely Decayed Primary Anterior Teeth retained by Glass Fiber Posts or Reversed-orientated Metal Posts.

ABSTRACT Aim: The aim of this study was to compare the survival of composite resin restorations retained by glass fiber posts or reversed-orientated (upside-down) metal posts in severely decayed primary anterior teeth after 6, 12, and 18 months. Materials and methods: A total of forty-four 3- to 5-year-old children with bilateral severely decayed primary maxillary canines were included. Patients were treated under general anesthesia. After pulpectomy, an intracanal post was seated in the primary maxillary canine on each side: either a glass fiber post or a metallic post in reversed orientation and teeth restored with light-cured composite. Survival rate of each technique was evaluated at predetermined follow-ups and data were analyzed with McNemar’s test (α = 0.05). Results: The difference in survival of restorations retained by two types of posts was not statistically significant in clinical and radiographical evaluations after 6, 12, and 18 months. The survival rate of reversed-orientated metal and glass fiber posts after 18 months was 81.1 and 67.6% respectively (p = 0.14). Conclusion: Reversed-orientated metal post did not show lower clinical survival compared with glass fiber posts in 18-month follow-up. Hence, reversed-orientated metal post can be considered as a potential method to obtain retention for composite restorations in severely decayed primary anterior teeth. How to cite this article: Vafaei A, Ranjkesh B, L0vschall H, Erfanparast L, Jafarabadi MA, Oskouei SG, Isidor F. Survival of Composite Resin Restorations of severely Decayed Primary Anterior Teeth retained by Glass Fiber Posts or Reversed-orientated Metal Posts. Int J Clin Pediatr Dent 2016;9(2):109-113.