Standards of teeth preparations for anterior resin bonded all-ceramic crowns in private dental practice in Jordan

Objectives: to investigate if general dental practitioners (gdps) in private practice in jordan follow universal guidelines for preparation of anterior teeth for resin bonded all-ceramic crowns (rbcs). material and methods: a sample (n = 100) of laboratory models containing 208 tooth preparations for ips empress and in ceram,featuring work from different gdps,was obtained from 8 commercial dental laboratories. aspects of preparations were quantified and compared with accepted criteria defined following a review of the literature and recommendations of the manufactures' guidelines. results: subgingival margins on the buccal aspect were noticed in 36% of the preparations,54% demonstrated overpreparation with a tendency to overprepare the teeth on the mesiodistal plane more than buccolingual plane. twenty percent of samples presented a shoulder finish line while a chamfer margin design was noticed in 39%. twenty-nine percent and 12% of samples had either a feathered or no clear margin design respectively. incisal underpreparation was observed in 18% of dies of each type. only 17% of all preparations were found to follow the recommended anatomical labial preparations while 29% of the rbc preparations were found to have the recommended axial convergence angle. in total,43% of preparations were found to have the recommended depth of the finish line. conclusions: it was found that relevant guidelines for rbc preparations were not being fully adhered to in private practice in jordan.