Irritants and Allergens in Dental Materials - A Review

This review aims to develop a systematic approach for the selection of suitable and safer dental materials available in the market thereby giving an insight to predict their risk of inducing allergic reactions. The review was conducted by referring to various relevant articles and retrospective studies.It was noted that the most common allergic reactions in dental staff are allergies to latex, acrylates and formaldehyde. The other dental materials that caused irritation included impression materials, metals, resins, rubber products, amalgam restorations. The study comprehended that dental personnel have high risk of allergy from latex gloves, bio aerosols inhaled during the dental practice, contact dermatitis and from the usage of various other potentially harmful dental materials. On the other hand, the patients have high risk of irritation from commonly used dental materials like metals (gold, mercury, chromium, palladium etc), root canal sealants, obturation materials, formaldehyde, amalgam restorations, resin, acrylates, impression materials, latex and local anesthesia. Patients begin to develop symptoms of stomatitis, burning, tingling, cheilitis, oral lichenoid lesions, lip and facial swelling. The oral cavity is exposed to various sensitizing substances that cause allergic reactions. Hence it is necessary to provide comprehensive dental treatment without compromising the health of the patient

The Efficacy of an Acrylic Intraocular Lens Surface Modified with Polyethylene Glycol in Posterior Capsular Opacification

To investigate if the surface modification of intraocular lens (IOL) is efficient in the prevention of posterior capsular opacification (PCO), the acrylic surface of intraocular lens (Acrysof(R)) was polymerized with polyethylene glycol (PEG-IOL). The human lens epithelial cells (1x10(4) cells/mL) were inoculated on PEG grafted or unmodified acrylic lenses for the control. The adherent cells on each IOL surface were trypsinized and counted. The every PEG-IOL was implanted in 20 New Zealand rabbits after removal of crystalline lens. The formations of PCO were checked serially through retroilluminated digital photography, and the severity scores were calculated using POCOman(R). The cell adherence patterns on each IOL were examined by scanning electron microscopy. As a result, the mean number of adherent cells of PEG-IOL (3.2+/-1.1x10(3)) tended to be smaller than that of the acrylic controls (3.6+/-1.9x10(3)) without a statistical significance (p=0.73). However, the mean severity of PCO formation in PEG-IOL was significantly lower than that in the control during the third to sixth weeks after surgery. Scanning electron microscopy revealed that the more patch-like cells were found firmly attached to the IOL surface in control than in the PEG-IOL. Conclusively, PEG polymerization to the acrylic IOL would possibly lessen the formation of PCO after cataract removal.

Preparation and property study of ion-exchange embolic microspheres for delivering pingyangmycin / 北京大学学报(医学版)

Objective:To develop and study the properties of ion-exchange polyvinyl alcohol-acrylic acid microspheres(PVA-AA-Ms) for embolization.Methods:The PVA-AA-Ms were produced by the method of inverse suspension polymerization.The morphology and particle size were determined by optical microscope;FT-IR was used to investigate the special functional groups of PVA-AA-Ms;the carboxyl content of PVA-AA-Ms was measured by chemical titration;the compression elasticity was examined by texture analyzer(TA-plus).Pingyangmycin(bleomycin A5) was used as model drug to prepare drug-loaded PVA-AA-Ms.Drug loading and entrapment efficiency were measured through UV-spectrophotometer;in vitro drug release characteristic was detected by constant temperature vibration dialysis assay.Results:The PVA-AA-Ms were round and integrated.The average diameter of PVA-AA-Ms was 500 ?m with a range of 150-1 000 ?m.The carboxyl vibration was demonstrated by FT-IR and the content of carboxyl was 8.905 mmol/g.PVA-AA-Ms were mechanically stable with appropriate elasticity.Drug loading and entrapment efficiency were 30 g/L and 99.4%,respectively.The drug release rate was slow in phosphate buffer solution(PBS),88.3% of the drug was released after 24 h and the t50 was 2.19 h.Conclusion:PVA-AA-Ms prepared in this study were supposed to be suitable for clinical embolization according to the physicochemical properties.The high carboxyl content of PVA-AA-Ms which allowed them to load cationic drugs(e.g.,drug with amino group) through ion-exchange mechanism brought broad prospects for combination of embolization and chemotherapy.