Elastic Chain Reinforced Scan Body Stabilization Technique for Improving Cross Arch Accuracy in Mandibular Full-Arch Digital Implant Impressions: A Two Case Series with Literature Review

Abstract

Digital workflows have significantly advanced full-arch implant rehabilitation; however, mandibular full-arch digital impressions remain prone to cumulative
stitching distortion due to anatomical and environmental challenges inherent to the lower arch. Limited attached mucosa, absence of palatal reference structures,
saliva pooling, and dynamic soft tissues may compromise scan continuity in All on 4 and All on 6 rehabilitations. This report describes a novel chairside stabilization
technique using orthodontic elastic chains reinforced with flowable composite to create a rigid inter-scan body reference structure during digital acquisition. Two
delayed-loading mandibular full-arch implant rehabilitations were treated. Case 1 involved six Neodent, PrimeTaper implants restored at the multi-unit level. Case
2 involved four bredent CopaSky implants placed according to the All-on-4 concept with posterior 30 degree angulated multi-unit abutments. In both cases, PEEK scan bodies were
splinted intraorally using elastic chains coated with flowable composite and light-cured prior to scanning. Digital impressions were obtained using a Medit intraoral scanner in Case 1
and a 3Shape TRIOS 3 in Case 2. Direct metal laser sintered titanium verification bars were fabricated from the digital files and evaluated clinically using the single screw test and
radiographic assessment. Both cases demonstrated complete passive fit without the need for adjustment. Within the limitations of this case series, the proposed technique appears to
enhance scan continuity and may reduce cumulative cross-arch distortion in mandibular full-arch digital implant impressions.