SUMMARIES dental materials Condensable metal-reinforced glass ionomer cements in primary molars

Clinical performance of a condensable metal-reinforced glass ionomer cement in primary molars by N. Krämer, R. Frankenberger Br Dent J 2001; 190: 317-321

Objective formation due to wear was frequently observed in Aim of the present study was to evaluate the clinical suitability occlusal parts. of the condensable metal-reinforced glass ionomer cement Hi-Dense in classes I and II cavities of primary molars. Conclusions The results clearly indicate that the condensable, metal-reinforced Methods GIC Hi-Dense reveals no enhanced performance and lifetime Seventeen children received a total of fifty four Hi-Dense fillings expectancy for class II restorations in primary molars when (nineteen class I and thirty five class II). The restorations were compared to other non-resin-modified GICs. clinically assessed at baseline, after one and after two years of clinical service according to modified USPHS codes and criteria. The restorations were replicated in each recall and representative In Brief samples were qualitatively analysed under a SEM. • Condensable glass ionomer cements with metal additions such as Hi-Dense provide favourable handling Results characteristics in children with low compliance. Over the observation period of two years, five restorations failed • Newer generation glass ionomers with higher viscosity like due to total retention loss, two fillings needed replacement Hi-Dense show the same disadvantages regarding flexural because of persisting hypersensitivity, one filling was lost because strength as their predecessors with lower viscosity such as of an unsuccessful endodontic treatment, and four restorations Ketac Silver. remained intact until natural exfoliation (Two year survival rate: • Independent of the stage of development it can be stated 92% for Class I and 66% for Class II). The SEM analysis of that non-resin-modified glass ionomers perform surfaces and marginal areas exhibited an inferior adhesive unsatisfactorily in Class II restorations of primary molars. performance primarily in proximal areas, whereas a negative step

Comment oncerns have been raised, particularly als to produce products that have more conclusion, it must be remembered that the Cin Europe, about the use of amalgam as favourable mechanical characteristics. This attachment strength of glass ionomer a restorative material in children. This has paper reports a small clinical study of the cements to both enamel and dentine is also led to the profession striving to develop use of one such material (Hi-Dense from compromised by the presence of salivary alternative materials for use in the decidu- Shofu) in the deciduous dentition of rela- pellicle on the surface of the prepared tooth ous dentition. Restorative care for the tively young patients in whom the chal- tissue, and that the clinical performance of deciduous dentition poses a series of chal- lenges of moisture control and patient all GICs is affected adversely by contamina- lenges to the practitioner in terms of the compliance would be relatively high. tion of the surface of the material with mois- size and shape of the cavities, the co-opera- There have been some reports in the liter- ture before the material has set adequately. tion of the patient and the nature of the ature of improved performance in the labo- It is worthy of note that the authors created substrates (deciduous enamel and dentine ratory of this newer high viscosity glass cavities in this study with slight undercuts, which are different in structure and miner- ionomer material. Unfortunately, the clini- which may have helped to retain the restora- alisation to the permanent equivalents) cal data reported in this study demonstrate tions in the study when chemical adhesion when an adhesive material is to be used. few apparent clinical benefits derived from may have failed. Clinical studies of alternative restorative the selection of this new product compared It would appear that this more recent materials in the deciduous dentition have with earlier metal reinforced glass ionomer generation of glass ionomer cements are been undertaken with the full spectrum of cements. The newer material seems to have no significant improvement on their pre- tooth coloured restorative materials from a similar pattern of clinical performance to decessors in their use within the deciduous conventional glass ionomer cement to both metal reinforced and conventional dentition, particularly for Class II restora- composite resins as well as metal reinforced glass ionomer cements when used in the tions where approximately one third of the /modified GICs. The clinical performance management of the deciduous dentition in restorations placed failed within the of glass ionomer cements has been disap- previous studies. However the handling 2.5 year follow-up period. pointing in this setting, but reflects their characteristics (notably its increased viscos- It would be reasonable to summarise that physical characteristics. These materials are ity) of the new product may offer some these materials offer some benefits in terms subject both to wear on the functional sur- advantages in terms of clinical placement. of their placement and clinical handling faces of the teeth and to bulk failure by frac- The authors conclude that there are characteristics in comparison with compos- ture in clinical service, particularly in advantages to the use of glass ionomer ite resin and compomer materials but have a extensive cavities. There are also concerns cements in unco-operative children where reduced life expectancy in oral function. about breakdown of marginal adaptation moisture control is particularly problemat- of the material to the tooth. ic but that other (resin-based) materials are A. W. G. Walls The manufacturers of glass ionomer preferable in the co-operative subject. Professor, Restorative Dentistry, The Dental cements continue to develop these materi- Care needs to be taken in interpreting this School, Newcastle upon Tyne

306 BRITISH DENTAL JOURNAL, VOLUME 190, NO. 6, MARCH 24 2001