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Year : 2022  |  Volume : 13  |  Issue : 2  |  Page : 74-75

Shifting focus from subtractive to additive technology in digital prosthodontics

Department of Prosthodontics, Indira Gandhi Institute of Dental Sciences, SBV University, Puducherry, India

Date of Submission29-Apr-2022
Date of Decision07-May-2022
Date of Acceptance09-May-2022
Date of Web Publication20-Jun-2022

Correspondence Address:
Prof. P S Manoharan
Department of Prosthodontics, Indira Gandhi Institute of Dental Sciences, SBV University, Puducherry
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/srmjrds.srmjrds_66_22

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The advancements in digital technologies have found a widespread application in fabrication of dental restoration with adequate precision and accuracy. Digital methods which are commonly used for fabrication of prosthesis include subtractive methods such as milling and additive methods such as photomelting and photopolymerizing. Digitalization and accuracy are paving the way toward additive technology. The main purpose of this short communication is to mention the advantages, applications, and studies comparing additive and subtractive technology.

Keywords: Additive technology, milling, selective laser sintering

How to cite this article:
Koppolu SK, Manoharan P S. Shifting focus from subtractive to additive technology in digital prosthodontics. SRM J Res Dent Sci 2022;13:74-5

How to cite this URL:
Koppolu SK, Manoharan P S. Shifting focus from subtractive to additive technology in digital prosthodontics. SRM J Res Dent Sci [serial online] 2022 [cited 2022 Jul 3];13:74-5. Available from:

The past 30 years witnessed the evolution of computer-aided designing (CAD)/computer-aided manufacturing (CAM), which paved the way for the development of numerous CAD/CAM systems with a wide range of applications from designing and fabrication of complete dentures, implant restorations, and maxillofacial prosthesis to planning and manufacturing of orthodontic appliances. The conventional wax patterns were gradually being replaced with digitally milled or printed resin patterns. The basic functional components involved in CAD/CAM systems are data acquisition, restoration design, and restoration fabrication.[1] The primary ways of digitally fabricating the prosthesis are by subtractive and additive technology.

Subtractive technology functions by milling/grinding of large solid blocks into a desired restoration using sharp cutting tools. Greater accuracy will be achieved using a smaller diameter cutting tool. They are classified into dry/wet milling and based on the number of axes (i.e., 3 axes, 4 axes, or 5 axes). The major advantage of subtractive technology is fabrication of homogeneous objects and fabrication of prosthesis which can withstand high occlusal load. The drawback of milling is wastage of the material, overmilling, and low retention of restoration.

Additive technology works on the principle of layer-on layer addition for the fabrication of objects. After designing the restoration, the CAD image is segmented into multislice images. The material will be laid down in incremental way to obtain a desired shape, which will be refined to obtain the final shape. There are multiple advantages in using additive technology such as no material wastage, incremental vertical buildup, fabrication of large objects, and fine details production. The major problem with additive technology is the shrinkage of model. There are several techniques which use additive technology such as stereolithography (SLA), selective laser sintering (SLS), fused deposition modeling, direct metal laser sintering, and direct light projection (DLP).[1] The commonly used materials used in digital manufacturing are mentioned in [Table 1].
Table 1: Materials used in digital manufacturing[1]

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Multiple studies were done comparing the additive and subtractive technologies in the recent decade. On comparing the complete dentures fabricated using rapid prototyping (3D printing) and CAD-CAM milling, CAD-CAM milled dentures showcased superior results in the trueness of the intaglio surface.[2] While the accuracy of surgical splints fabricated with milling was superior compared to 3D printing.[3] Some studies mentioned the superiority of additive technology. Additive techniques such as SLA and DLP showed better adaptation of denture metal bases than the milling technique. Whereas among additive, SLA showed smooth and precise margins compared to the DLP technique.[4] The accuracy of inlay restoration was superior with additive technique (SLA and SLS) than milling.[5]

CAM continues to undergo significant and regular improvements. Various approaches are evolving in additive technology in strive of achieving accurate results. Henceforth, further research should be focused on achieving more precise results using additive technology.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Alghazzawi TF. Advancements in CAD/CAM technology: Options for practical implementation. J Prosthodont Res 2016;60:72-84.  Back to cited text no. 1
Kalberer N, Mehl A, Schimmel M, Müller F, Srinivasan M. CAD-CAM milled versus rapidly prototyped (3D-printed) complete dentures: An in vitro evaluation of trueness. J Prosthet Dent 2019;121:637-43.  Back to cited text no. 2
Palazzo G, Ronsivalle V, Oteri G, Lo Giudice A, Toro C, Campagna P, et al. Comparison between additive and subtractive CAD-CAM technique to produce orthognathic surgical splints: A personalized approach. J Pers Med 2020;10:273.  Back to cited text no. 3
You SG, You SM, Kang SY, Bae SY, Kim JH. Evaluation of the adaptation of complete denture metal bases fabricated with dental CAD-CAM systems: An in vitro study. J Prosthet Dent 2021;125:479-85.  Back to cited text no. 4
Bae EJ, Jeong ID, Kim WC, Kim JH. A comparative study of additive and subtractive manufacturing for dental restorations. J Prosthet Dent 2017;118:187-93.  Back to cited text no. 5


  [Table 1]


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