The global prevalence of edentulism ranges between 3-21% and as populations age the risk of tooth loss increases. Conventional removable complete dentures (CDs) are an established treatment approach but the use of computer-aided design and computer-aided manufacturing (CAD-CAM) techniques for CDs is gaining in popularity as they can be constructed in as little as two visits.
The aim of this review was to assess if, in completely edentulous patients, CAD-CAM removable complete dentures (CDs) are inferior to conventional CDs with respect to trueness of fit, biocompatibility, mechanical properties, surface characteristics, colour stability, time-cost efficiency, clinical and patient-reported outcomes?
Methods
A review protocol was registered in PROSPERO. Searches were conducted in the Cochrane CENTRAL, Medline/PubMed, Embase, Google Scholar, Yahoo and www.researchgate.net with no restrictions. Studies of any design reporting on CDs manufactured by CAD-CAM (milled/3D-printed) and conventional processes were considered. Two reviewers searched and selected studies with data extraction performed independently by 2 reviewers. Meta-analysis was performed comparing CDs manufactured using CAD-CAM and traditional processes with regard to trueness of fit, biocompatibility, retention, flexural strength, flexural modulus, yield strength, strain at yield point, toughness, fracture toughness, hardness, surface wettability, surface roughness, colour stability, residual monomer content, clinical and patient reported outcomes (PROMS).
Results
- 73 studies were included with 39 contributing to the meta-analyses.
- Meta-analyses were conducted for a number of parameters (see tables)
Trueness of fit (mm)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 10 | -0.660(-1.329 to 0.009) |
| milled CDs to injection-molding | 5 | 0.129 (-1.248 to 1.507) |
| milled CDs to 3D-printing | 9 | -0.810 (-2.547 to 0.926) |
| 3D-printed CDs to conventional flask-pack-press | 5 | -0.921 (-1.795 to -0.048) |
| 3D-printed CDs to injection-molding | 2 | 0.110 (-2.987 to 3.207) |
| 3D-printed CDs to milled CDs | 11 | 0.810 (-0.926 to 2.547) |
| 3D-printed CDs to used deposition modelling | 1 | 0.057 (-1.183 to 1.297) |
Flexural strength (MPa)
| Comparison | No. of comparisons | SMD (95%CI) |
| Milled CDs to composite | 2 | -1.530 (-2.006 to -1.055) |
| milled CDs to conventional (flask-pack-press) | 13 | -2.335 (-3.710 to -0.959) |
| milled CDs c to injection-molding | 3 | -2.969 (-4.876 to -1.061) |
| milled CDs c to 3D-printing | 8 | -4.198 (-5.490 to -2.906) |
Flexural modulus (MPa)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 5 | -1.858 (-4.647 to 0.931) |
| milled CDs to injection-molding | 2 | -4.461 (-21.278 to 12.356) |
| milled CDs to 3D-printing | 8 | -7.596 ( -10.317 to -4.875 |
Yield strength (MPa)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 2 | 1.706 (-5.368 to 8.781) |
| milled CDs to injection-molding | 1 | -0.850 (-1.428 to -0.271) |
| milled CDs c to 3D-printing | 8 | -1.100 (-1.760 to -0.439) |
Strain at yield point (MPa)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 1 | 4.464 (2.148 to 6.781) |
| milled CDs to 3D-printing | 8 | 0.058 (-0.552 to 0.933) |
Toughness (N/mm)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 1 | -7.609 (-11.167 to -4.051) |
| milled CDs to 3D-printing | 8 | -1.987 (-2.613 to -1.362) |
Fracture toughness (MP/ m2)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 7 | 0.357 (-1.399 to 2.112) |
| milled CDs to injection-molding | 1 | -1.106 (-2.322 to 0.109) |
| milled CDs to self-cure | 6 | -0.146 (-1.957 to 1.665) |
Hardness (MPa)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 6 | -2.170 (-4.945 to 0.605) |
| milled CDs to injection-molding | 2 | 0.111 (-4.493 to 4.716) |
| milled CDs to self-cure | 6 | -1.294 (-3.454 to 0.866) |
Surface wettability (degree)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 15 | -0.292 (-1.238 to 0.654) |
| milled CDs to injection-molding | 1 | -0.506 (-1.386 to 0.385) |
Surface roughness (mm)
| Comparison | No. of comparisons | SMD (95%CI) |
| milled CDs to conventional (flask-pack-press) | 18 | -1.494 (-2.152 to 0.766) |
| milled CDs to injection-molding | 1 | -4.105 (-5.650 to -2.560) |
| milled CDs to Polyamide | 1 | 50.569 (28.372 to 72.766) |
| milled CDs to 3D-printing | 7 | -1.122 (-1.602 to -0.642) |
| milled CDs to self-cure | 3 | 62.006 (-18.080 to 142.093) |
Colour stability
| Comparison | No. of comparisons | SMD (95%CI) |
| 3D-printing to conventional (flask-pack-press) [Pink shade] | 1 | 2.266 (0.490 to 4.042) |
| 3D-printing to milled CDs [Pink shade] | 4 | 1.439 (0.278 to 2.600) |
| 3D-printing to conventional (flask-pack-press) [Tooth shade] | 1 | -1.310 (-2.837 to 0.217) |
| 3D-printing to milled CDs [Tooth shade] | 4 | 1.139 (-1.115 to 3.394) |
| Overall | 5 | 0.860 (0.090 to 1.631) |
Residual monomer content
| Comparison | No. of comparisons | SMD (95%CI) |
| Milled CDs and conventional (flask-pack-press) | 10 | -0.926 (-1.997 to 0.144) |
Retention
| Comparison | No. of studies | SMD (95%CI) |
| Conventional (flask-pack-press) to 3D-printing | 1 | 3.608 (0.431 to 6.785) |
| Conventional (flask-pack-press) to milled CDs | 1 | 0.662 (0.26 to 1.299) |
| Overall | 2 | 0.776 (0.152 to 1.400) |
Aesthetics (clinicians VAS scores)
| Comparison | No. of comparisons | SMD (95%CI) |
| Conventional (flask-pack-press) to 3D-printing | 1 | 3.608 (0.431 to 6.785) |
| injection-molding to milled CDs | 1 | 0.000 (-1.240 to 1.240) |
| Overall | 2 | -1.337 (-2.192 to -0.483) |
Costs (Swiss francs) – milled CDs to conventional (flask-pack-press)
| No. of studies | SMD (95%CI) | |
| Clinical materials | 1 | 10.251 (7.182 to 13.321) |
| Lab costs | 1 | -3.930 (-5.328 to -2.532) |
| Overall costs | 2 | -2.592 (-3.579 to -1.606) |
Chair-side time (minutes) Milled CDs and conventional (flask-pack-press)
| No. of studies | SMD (95%CI) | |
| Lab costs – Upper denture only | 1 | -1.873 (-3.230 to -0.516) |
| Lab costs – Upper & lower dentures | 1 | -5.071 (-7.394 to -2.784) |
| Overall | 1 | -3.327 (-6.448 to -0.206) |
Conclusions
The authors concluded: –
CAD-CAM CDs offer a number of improved mechanical/surface properties and are not inferior when compared to conventional CDs. However, further long-term follow-up studies are required to fully evaluate these CAD-CAM CDs with particular regard to aesthetics sand PROMs.
Comments
The authors registered their review in the PROSPERO database and searched 3 major databases and other grey literature sources. 73 studies were included most were heterogeneous, small in size and involved a number of comparisons with a majority being undertaken in vitro. 39 studies contributed to the meta-analyses of a broad range of parameters with few of the analyses involving more than 10 comparisons. While the authors planned to assess patient reported outcomes (PROMS) the available studies seldom used validated PROMS and no studies used quality of life. The review provides and extensive summary of the available literature and suggests that there is little technical difference between CAD-CAM complete dentures and traditional approaches. However, more in-vivo clinically relevant studies of appropriate size and duration with a focus on PROMS ,aesthetics and costs are needed.
Links
Primary Paper
Srinivasan M, Kamnoedboon P, McKenna G, Angst L, Schimmel M, Özcan M, Müller F. CAD-CAM removable complete dentures: A systematic review and meta-analysis of trueness of fit, biocompatibility, mechanical properties, surface characteristics, color stability, time-cost analysis, clinical and patient-reported outcomes. J Dent. 2021 Oct;113:103777. doi: 10.1016/j.jdent.2021.103777. Epub 2021 Aug 13. PMID: 34400250.
Other references
Dental Elf – 30th Aug 2022
Dental Elf – 9th Apr 2018
