Clinical performance of esthetic posterior crowns in primary molars: a pilot study. Clinical performance and caries inhibition of resin-modified glass ionomer cement and amalgam restorations. Dyract versus Tytin Class II restorations in primary molars: 36 months evaluation.
The aim of this pilot study was to assess the clinical performance of esthetic crowns and to compare these to conventional stainless steel crowns (SSC).
                Twenty two crowns (11 conventional and 11 esthetic) were placed in mandibular primary molars obeying the following criteria: the tooth was not mobile; no fistulae were present; the tooth had at least one caries free or properly restored antagonist and had to be in contact with one adjacent tooth mesially, in the case of the primary second molars or distally in the case of the primary first molars. Crown preparation was done in a conventional manner, but reduction was more extensive for the thicker esthetic crowns, to allow for proper occlusion. The crowns were evaluated clinically and radiographically after 6 months and the following parameters were assessed: gingival health, marginal extension, crown adequacy, proper position or occlusion, proximal contact, chipping of the facing (for esthetic crowns) and cement removal.
                At the 6 month evaluation all esthetic crowns were intact, without chipping of the facing, and no excess of cement was observed in both groups. No difference was found for marginal extension, occlusion, proximal contact, crown adequacy, and bone resorption, but a significant difference was found for periodontal health between esthetic crowns and conventional SSC (P < 0.001 McNemar test).
                The esthetic crowns assessed had several inconveniences, as they resulted in poor gingival health, are very expensive, and, although not measured, are bulky and without a natural appearance. The authors clinically examined two restorative materials to evaluate their effectiveness in Class II restorations in primary molars and their ability to inhibit recurrent caries.
                Forty subjects, each in need of two Class II restorations in primary molars, took part in this study. Each patient received one Class II restoration of resin-modified glass ionomer cement and one of amalgam. The authors evaluated the restorations at six-month, one-year, two-year and three-year recall appointments. On exfoliation, teeth with experimental restorations were retrieved and microscopically examined for inhibition of demineralization at restoration margins.
                The results of the clinical evaluation demonstrated no significant differences between the resin-modified glass ionomer cement restorations and the amalgam restorations (P < .05). Polarized light microscopic examination of the returned teeth that were restored as a part of this study indicated that the resin-modified glass ionomer cement had significantly less enamel demineralization at restoration margins than did amalgam (P < .0001).
                The resin-modified glass ionomer cement functioned clinically as well as amalgam for Class II restorations in primary molars. However, the resin-modified glass ionomer exhibited significantly less enamel demineralization at restoration margins than did amalgam.
                Resin-modified glass ionomer cement restorative material functions well for Class II restorations in primary molars and exhibits less recurrent caries at restoration margins than does amalgam. Due to the changed treatment approach of proximal caries and the amalgam controversy, clinicians are in search for new materials. The aim of the present study was to compare amalgam with an adhesive material in deciduous molars in a clinical, split-mouth design study. At baseline 30 polyacid modified composite (Dyract) and 30 amalgam (Tytin) restorations were placed in primary molars, of which 24 and 17 could be evaluated after 24 and 36 months, respectively. Modified USPHS criteria were used for clinical evaluation every 6 months. Annual bite-wing radiographs were taken for evaluation of recurrent caries and cervical gap formation. In the present study, for Dyract as well as for Tytin restorations, low rates of recurrent caries were found, while Dyract restorations showed a better marginal adaptation and surface texture compared to Tytin restorations. In the Dyract group more radiolucencies were found at baseline. In both groups no patient complaint or pain was reported related to the radiolucencies. After 3 years the colour of Dyract was not comparable to the original. For Dyract no excessive wear was noticed compared to enamel. During the study one Dyract (recurrent caries: 18 months) and two Tytin (pulpal aetiology: 6 months, recurrent caries: 36 months) restorations had to be replaced. Even though the restorations were placed in caries risk children, at the 36 months' evaluation of this clinical study, the results indicate that Dyract can be an alternative for Tytin in the primary dentition.
It was disappointing that only three trials that compared three different types of materials were suitable for inclusion into this review. There were no significant differences found in all three trials for all of the outcomes assessed. Well designed, randomised controlled trials comparing the different types of filling materials for similar outcomes are urgently needed in dentistry. There was insufficient evidence from the three included trials to make any recommendations about which filling material to use.