Objective: This study examined the reasons given by vocational dental practitioners and their trainers for placement and replacement of restorations. Methods and materials: Each participant was asked to record the reason for placement or replacement of restorations. The age and class of the restoration being replaced were also recorded, as was the material being used and the material being replaced (if known). Results: Details of the reason for placement or replacement was received on 9.031 restorations. Of the restorations placed, 53.9% were amalgam, 29.8% were resin composite, and 16.3% were glass-ionomer cement. The reasons for placement or replacement of the restorations were principally primary caries (41.3%), secondary caries (21.9%), tooth fracture (6.4%), marginal fracture or degradation (6.1%), and noncarious defects (5.8%). Of the amalgam restorations, most were placed to restore Class II and Class I preparations (65.8% and 29.9%, respectively). Of the composite restorations, most were placed in Class III and Class V cavities (35.5% and 26.3%, respectively). Glass-ionomer cement was used predominantly to restore Class V cavities (63.5%). Conclusion: Secondary caries was the most prevalent reason for replacement of restorations, regardless of material. Statistical analysis indicated that amalgam provided significantly greater longevity than composite or glass-ionomer materials.