Custom Trays Edged Stock Trays in Lab Study of Complete-Arch Implant Impressions

Edited by Dentaltown staff

Custom trays produced more accurate definitive casts than stock trays in an in vitro study of maxillary complete-arch implant impressions, though the difference did not hold up under every statistical analysis, according to research published online Oct. 23 in The Journal of Prosthetic Dentistry.

Reinforcing the splinted impression copings with heavy-body polyvinyl siloxane before making the impression did not significantly improve accuracy (P = .104).

The investigators tested stock and custom trays, each with and without subsplint reinforcement, for four conditions with nine impressions per group. In the nonreinforced groups, heavy-body PVS was placed in the tray and light-body PVS was applied around the splinted copings. In the reinforced groups, heavy-body PVS was placed gingival to the splinting device and polymerized before the impression was made.

Definitive casts were digitized and superimposed onto a control model, and trueness was measured as the three-dimensional root mean square deviation between scan body surfaces. Values ranged from 36 to 580 micrometers.

Tray type had a statistically significant effect in the primary two-way analysis of variance (P = .045) and in a permutation analysis (P = .011), but not in a heteroscedasticity-consistent analysis (P = .112). The interaction between tray type and reinforcement was not significant (P = .099).

L. Kurdi of Umm al-Qura University in Saudi Arabia conducted the study with G.A. Thompson and M. El-Shewy of the Dental College of Georgia at Augusta University, M.B. Karczewski of Marquette University School of Dentistry, and C. Drago, who is in private practice in Milwaukee.

The authors cautioned that the findings should be interpreted carefully because the significance of the tray effect varied with the analytical approach. The study used a laboratory model and did not assess clinical fit.

Sources:
The Journal of Prosthetic Dentistry, “Effect of tray type and subsplint reinforcement on the trueness of complete arch implant impressions: An in vitro study,” published online Oct. 23, 2026: sciencedirect.com/science/article/pii/S0022391326006645
National Library of Medicine, PubMed, PMID 42919773: pubmed.ncbi.nlm.nih.gov/42919773