A trans-well-based cellular model for the rapid pre-evaluation of tympanic membrane repair materials.

It is important to have a standardized tympanic membrane (TM) perforation platform to evaluate the various myringoplasty materials that have been studied and developed extensively during recent years. However, currently there are no cellular models specifically designed for this purpose, and animal models remain unsatisfactory. The purpose of this study is to propose an inexpensive, readily available, well-controlled, and easy-to-create cellular model as a substitute for use in the evaluation of TM repairing materials. A trans-well model was created using a cell culture insert with a round hole created at the center of the polycarbonate membrane. HaCaT cells were cultured on the fenestrated culture insert, and the desired myringoplasty graft was placed at the center of the window for one week and observed by fluorescent microscopy under vital staining. Under this cellular model, there was notable migration of HaCaT cells onto the positive control graft (rabbit fascia), while only a few cell clusters were observed on the negative control graft (paper). Model validation showed that the cell migration ratio for the PLLA + 1% hyaluronic acid (HA) graft is significantly higher than using myringoplasty paper, poly L-lactide (PLLA), or PLLA + 0.5% HA (p < 0.05). This trans-well-based cellular model might be a useful pre-evaluation platform for the evaluation of TM repairing materials. The model is inexpensive, readily available, easy to create, and standardized for use.

Bactericidal eradication from carious lesions of prepared abutments by an antibacterial temporary cement.

PURPOSE: The aim of this study was to observe the antibacterial potential of polycarboxylate temporary cement containing a mixture of metronidazole, ciprofloxacin, and cefaclor on carious lesions of prepared abutments that were designed to leave caries on the abutments. MATERIAL AND METHODS: Antibacterial efficacy was estimated in vitro and in vivo by measuring bacterial recovery from the lesions. Bacteria counts ranged from 10(4) to 10(7) both in vitro (nine samples) and in vivo (five samples) in time-zero samples, just before the application of the antibacterial cement. RESULTS: No bacteria were recovered from carious lesions in vitro (six samples) or in vivo (four samples) after the lesions were covered by the antibacterial temporary cement. For the remaining samples, some bacteria (5 to 80 counts per sample) were recovered, with one notable exception in which marginal leakage provided a bacteria count of 10(3). Bacteria counts ranging from 10(3) to 10(5) occurred in carious lesions covered by temporary cement without antibacterial agents, which indicated that temporary cement alone was not a potent disinfectant. CONCLUSIONS: The results of this study indicated that the antibacterial temporary cement can be useful for eradicating bacteria from carious lesions of prepared abutments.

An in-vitro comparative study of the retention of grooved and flat endodontic posts in treated root canals using two different types of cements.

This study evaluated and compared the retentive capability of performed cast posts in endodontically treated premolar teeth using the following: 1--smooth versus grooved post design 2--surface treatment of the root canals with either 17% EDTA followed by 2.25% Naocl or using Naocl only. 3--cementation of the posts with either polycarboxylate cement or C & B Metabond. Cast metal posts were made, cemented in root canals and divided into groups representing combinations of variables. The force required for post removal were recorded and statistically analysed. The results indicated that cementation of the grooved cast metal post with polycarboxylate cement after removal of the smear layer was the most retentive system. More over C & B Metabond resin cement with any post design in presence or absence of smear layer gave high retentive values.

[Comparative morphological characteristics of the pulp reaction to direct coating with therapeutic packings]. / Sravnitel'naia morfologicheskaia kharakteristika reaktsii pul'py na priamoe pokrytie razlichnymi lechebnymi prokladkami.

In experiments performed on green monkeys the molar pulp response to direct coating with calmecin and polycarboxylate cement saturated with the potassium nitric solution. Compared, the results of morphological pulp investigation showed the polycarboxylate cement with saturated potassium nitrate solution coating to be most effective. It had a rather good odontotropic effect and increased the protective action of the pulp. Polycarboxylate cement with saturated potassium nitrate solution coating is recommended for clinical trials to treat occasional pulp denudation.