Comparison of digital and conventional methods of fit evaluation of partial removable dental prosthesis frameworks fabricated by selective laser melting.

STATEMENT OF PROBLEM: Three-dimensional (3D) printing technology may improve the fit of partial removable dental prosthesis frameworks made by selective laser melting. Conventionally, the gaps between definitive casts and prostheses are evaluated by using clinical replicas, but digital evaluations may provide a better alternative. PURPOSE: The purpose of this in vitro study was to compare digital and conventional methods for evaluating the fit of partial removable dental prosthesis frameworks made by selective laser melting. MATERIAL AND METHODS: A printed resin definitive cast representing a Kennedy class II modification 2 design with 5 reference markers was made from a dentiform cast. Twelve cobalt-chromium partial removable dental prosthesis frameworks were fabricated by selective laser melting on this definitive cast with a digital design software program. The gaps between the frameworks and the cast were assessed by using the clinical replica method with a silicone impression material and measuring the thickness at each marker with calipers. Digital casts of each framework and the definitive cast were scanned and then registered with the CloudCompare software program to measure 3D gaps at the 5 reference markers and 3 occlusal rests. The results were analyzed individually for each technique by 1-way analysis of variance (ANOVA) with post hoc Bonferroni tests (α=.05). RESULTS: For clinical registration, the mean gap between the frameworks and definitive cast was 13.9 ±7.6 µm. For digital registration, the root mean square gap was 70.7 ±24.2 µm. Statistically significant differences among the gaps for different markers were found for both approaches (P<.05). There were no significant differences among the gaps between the different frameworks. In both situations, the gap measurements were below the 300-µm clinically acceptable standard. CONCLUSIONS: Both registration methods determined whether the fit of a framework fabricated by selective laser melting was within a clinically acceptable standard. The differences in the values produced most likely arose from the different registration methods.

Maxillary complete-arch implant-supported restoration: A digital scanning and maxillomandibular relationship workflow.

Intraoral scanners are increasingly used as a replacement for conventional impressions, including the capturing of edentulous arches, although their use may be clinically challenging. This technique article describes the fabrication and use of a custom scanning device to scaffold an intraoral complete-arch scan of at least 6 implant scan bodies in the edentulous maxilla while simultaneously capturing the maxillomandibular relationship for the purpose of establishing a digital workflow to fabricate a maxillary complete-arch implant-supported prosthesis.

Management of a Class I malocclusion with traumatically avulsed maxillary central and lateral incisors.

This case report describes orthodontic space closure for managing an avulsed maxillary central incisor and a lateral incisor in a growing girl with a Class I deep bite malocclusion with moderate lower and mild upper crowding. The treatment approach moved a central incisor across the midline and substituted a lateral incisor for a central incisor, in combination with canine substitution. Veneers on all maxillary anterior teeth attained acceptable esthetics. The right central incisor was moved to serve as the avulsed left central incisor. The right lateral incisor was moved to the position of the right central incisor and restored. The canines on both sides were substituted as lateral incisors; the posterior occlusion was left in Class II. Mesialization of central and lateral incisors with prosthetic rehabilitation is an acceptable treatment option.