A New Proposal for Three-Dimensional Positioning of the Chin Using a Single Computer-Aided Design/Computer-Aided Manufacturing Surgical Guide

Clinical Relevance Computer-aided design/computer-aided manufacturing (CAD/CAM) composite resins are susceptible to degradation by dietary solvents. Dietary counselling is prudent when placing such CAD/CAM restorations. SUMMARY This study determined the effect of dietary solvents on the surface roughness (Ra) of direct, indirect, and computer-aided design/computer-aided manufacturing (CAD/CAM) dental composites. The materials evaluated were a direct composite (Filtek Z350 XT [FZ]), an indirect composite (Shofu Ceramage [CM]), and four CAD/CAM composites (Lava Ultimate [LU], Shofu Block HC [HC], Cerasmart [CS], and Vita Enamic [VE]). Specimens (12×14×1.5 mm) of each material were prepared, measured for baseline Ra, ranked, divided into six groups (n=12), and conditioned in the following media for 1 week at 37°C: air (control), distilled water, 0.02 N citric acid, 0.02 N lactic acid, heptane, and 50% ethanol-water solution. The composite specimens were then subjected to postconditioning Ra testing using an optical three-dimensional surface analyzer (G4e, Alicona Imaging GmbH, Raaba, Austria). Inter-medium and inter-material comparisons were performed with one-way analysis of variance and post hoc Bonferroni test at a significance level of α=0.05. Mean Ra values ranged from 0.086 ± 0.004 μm to 0.153 ± 0.005 μm for the various material/medium combinations. For all materials, conditioning in air (control) and distilled water generally resulted in significantly lower mean Ra than exposure to other dietary solvents. Conditioning in citric acid presented the roughest surfaces for FZ, CM, and CS. For LU, HC, and VE, exposure to lactic acid, heptane, and ethanol solution resulted in the highest mean Ra. Regardless of conditioning media, FZ had the highest and VE the lowest mean Ra compared with other composites. The CAD/CAM composites remained susceptible to surface degradation by dietary solvents despite their industrial polymerization.

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The accuracy of computer-aided design and manufacturing surgical-guide for infrazygomatic crest miniscrew placement

APOS Trends in Orthodontics ◽

10.25259/apos_127_2020 ◽

2021 ◽

Vol 11 ◽

pp. 48-55

Author(s):

Prajak Jariyapongpaiboon ◽

Jirawan Chartpitak ◽

Jaturong Jitsaard

Keyword(s):

Computer Aided Design ◽

Three Dimensional ◽

Surgical Guide ◽

Surgical Guides ◽

Computer Aided ◽

Design And Manufacturing ◽

Cad Cam ◽

The Right ◽

Aided Design ◽

3D Software

Objectives: Infrazygomatic crest (IZC) surgical guides have been employed to prevent any avoidable complications during miniscrew insertion. The purpose of this study was to evaluate the accuracy of IZC miniscrew placement when using a surgical-guide developed by computer-aided design and manufacturing (CAD/CAM) techniques. Materials and Methods: Ten patients were scanned with cone-beam computed tomography for three-dimensional (3D) planning of IZC miniscrew placements. The upper arches were scanned separately, and virtual miniscrews were placed in the position planned by 3D software. The CAD/CAM surgical guides were designed and fabricated individually to enable accurate miniscrew placement. Subsequently, 20 self-drilling miniscrews were inserted at the right and left IZC areas using 5 CAD/CAM surgical guides (CS group, n = 10) and direct insertion (DI group, n = 10), respectively. Pre- and post-operative digital model images were compared, actual and planned miniscrew positions were superimposed and measured for 3D angular and distance deviations in the two groups. Comparisons between groups were made using the Kruskal–Wallis test. Results: In the CS group, the median coronal and sagittal angular deviations were 2.95 degrees (range 0.34–5.26 degrees) and 2.05 degrees (range 0.38–4.08 degrees), respectively, while the median coronal and apical deviations were 0.39 mm (range 0.24–0.51 mm) and 0.50 mm (range 0.16–0.66 mm). These deviations differed significantly from those of the DI group. Conclusion: The IZC CAD/CAM surgical guide has made it possible to control miniscrew placement with high precision.

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