Please activate JavaScript!
Please install Adobe Flash Player, click here for download
ePaper created 2018-03-23, 14:32:14 | version 1.38.0
14 Dental Tribune Middle East & Africa Edition | July- August 2014academia tribune < Page 13 > Page 29 PROMEDICA Dental Material GmbH phone: +49 43 21/5 41 73 · fax +49 43 21/5 19 08 · Internet: www.promedica.de · eMail: info@promedica.de high quality glass ionomer cements first class composites innovative compomers modern bonding systems materials for long-term prophylaxis temporary solutions bleaching products … All our products convince by excellent physical properties perfect aesthetical results Light-curing nano-ceram composite • highly esthetic and biocompatible • universal for all cavity classes • comfortable handling, easy modellation • also available as flowable version Glass ionomer luting cement • highly biocompatible, low acidity • micro-fine film thickness • excellent adhesion • no temperature rise during setting Visit us at www.promedica.de Dental desensitising varnish • treatment of hypersensitive dentine • fast desensitisation • fluoride release • easy and fast application of immature permanent teeth must satisfy different goals than treatment for mature perma- nent teeth, due to the central role of the pulp in the physiologi- cal continuation of root develop- mentandinfurtherdepositionof primary dentin which strength- en the root dentinal walls. Thus, preservation of pulp vitality is particularly important in the im- mature permanent teeth, even with very different treatment in- dications. c. Remaining dentin Effective protection from the chemical and bacterial irritants depends on the following two parameters (Smith 2002): i. The remaining dentin thick- ness has been widely recognized as the main factor which deter- mines the long-term success of the treatment, in absence of bac- teria. In general remaining den- tin thickness more than 1 mm is considering to be a safe limit for adequate pulp protection. ii. Situation and dimensions of the exposed dentinal surface in the cavity seem to influence the overall dentin permeability through the number of exposed and open dentinal tubules. d. Operative trauma The operative trauma has been also implicated with pulpal inju- ry and subsequent pulp healing. Frictional heat due to uncon- trolled mechanical cavity prepa- ration, over-drying of the ex- posed dentin, direct damage to odontoblastic processes in deep cavities, and the chemical treat- ment of the dentinal surface due to acid-etching, may be associ- ated with transient pulp dam- age and/or increased dentinal sensitivity, which can delay pulp healing, while also development irreversible pulpitis cannot be excluded. The role of materials - In gen- eral similar materials are widely used in today clinical practice for both sites, pulp protection in deep sound dentinal cavities, and in active carious dentinal le- sions, despite the facts that the objectives of the two techniques are clearly different. For many years the hard setting zinc ox- ide eugenol cements have been used under amalgam restora- tions, and the calcium hydrox- ide-containing cements have been considered as materials of choice for pulp protection in deep dentinal cavities, especial- ly in cases of indirect pulp treat- ment. Conventional glass iono- mers, as well as resin-modified glass ionomers have been evalu- ated during the last two decades, while direct application of adhe- sive materials in the base of the cavity has also been proposed. Recently calcium silicate-based materials, acting as dentin re- placement materials, are under preclinical and clinical evalua- tion. Four criteria seem to be con- cerned to the characterization of an effective pulp protective ma- terial (see table): Physical properties Adherence to dentin, resistance to dissolution, setting time, flow, and dimensional stability repre- sent the most important physi- cal properties of an ideal pulp protective material. The physi- cal limitations of Ca(OH)2 –based materials, such as the non-ad- herence to dentin, dissolution in tissue fluids and degradation upon tooth flexure ranked them in the last position of the materi- als for using in pulp protection. Lack of any adherence to dentin has also been found for the zinc oxide-eugenol based materials. On the opposite excellent physi- cal and mechanical properties have been reported for the res- inous materials. The glass iono- mers present several important properties, such as an elasticity similar to dentin, and bonding to dentin and enamel. However glass ionomers are not resistant to water and have a slow setting rate. Improved physical proper- ties have been obtained with the resin modified glass ionomers. Newly released calcium silicate- based dentin substitutes have also showed interesting physico- chemical properties. Antibacterial activity It is widely accepted that the ability of the pulp protective ma- terial to reduce bacterial leakage and to prevent post-operative growth of leaking bacteria and their invasion into dentinal tu- bules is the most critical require- ment to avoid deleterious pulp inflammation and necrosis (Ber- genholtz 2005, Smith, 2002, Tzi- afas 2010). Furthermore several micro-organisms could be iso- lated from deep carious lesions and hence, the use of a material with antimicrobial activity un- derneath restorations has been highly recommended. Since bacteria can differentially affect the ability of odontoblasts to re- pair the dentine barrier function, the role of capping material in reduction of bacterial growth is important. Histological inves- tigations have demonstrated prevention for bacterial growth in almost 100% of the restora- tions with glass ionomer-based materials, in caries free teeth of young adults for post-operative period up to one year. In a few recent studies the MTA and hydroxyapatite-based materials showed significantly better an- tibacterial activity than Ca(OH)2 . Biocompatibility Absence of cytotoxic effects and biocompatibility of the restora- tive materials are reasonably of critical importance to reduce the possibility of pulp tissue ir- ritation or degeneration. Various cell culture systems, implanta- tion testing models in animals or usage tests in animal or hu- man teeth have been repeatedly evaluated the biocompatibility of materials used as pulp pro- tective bases. Calcium hydrox- ide-based materials have been much studied and represent the gold standard in the research of dental material biocompatibility. Conventionalglassionomersare highly biocompatible materials, while the resin modified glass ionomers, the resin composites and the adhesive systems have been shown to be considerably more cytotoxic, due to the re- lease of non-polymerized mono- mers (BISGMA, UDMA, TEG- DMA, HEMA). These monomers can cause directly pulp inflam- mation in toxic concentrations, or dramatic reduction of the de- fensive ability of the pulp in sub- toxic concentrations. However histological studies in deep cavi- ties of human teeth are expected to confirm these issues. Biospecificity It is associated with the capabil- ity of material to stimulate re- duction of dentin permeability (barrier function). Systematic in- vestigations on the ability of the use pulp protective materials, in- cluding the gold standard group of calcium hydroxide-based ma- terials, to mediate inflammation in the underlying pulp and to