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Digital Dentistry — 3D Printing Applications

March 2017
Journal of Interdisciplinary Medicine 2(1)

DOI:10.1515/jim-2017-0032

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CC BY-NC-ND 3.0

Authors:

Cristian Zaharia

Victor Babes University of Medicine and Pharmacy of Timisoara

Alin Gabor

Victor Babes University of Medicine and Pharmacy of Timisoara

Andrei-Mihai Gavrilovici

Victor Babes University of Medicine and Pharmacy of Timisoara

Adrian Tudor Stan

Victor Babes University of Medicine and Pharmacy of Timisoara

Show all 7 authorsHide

Three-dimensional (3D) printing is an additive manufacturing method in which a 3D item is formed by laying down successive layers of material. 3D printers are machines that produce representations of objects either planned with a CAD program or scanned with a 3D scanner. Printing is a method for replicating text and pictures, typically with ink on paper. We can print different dental pieces using different methods such as selective laser sintering (SLS), stereolithography, fused deposition modeling, and laminated object manufacturing. The materials are certified for printing individual impression trays, orthodontic models, gingiva mask, and different prosthetic objects. The material can reach a flexural strength of more than 80 MPa. 3D printing takes the effectiveness of digital projects to the production phase. Dental laboratories are able to produce crowns, bridges, stone models, and various orthodontic appliances by methods that combine oral scanning, 3D printing, and CAD/CAM design. Modern 3D printing has been used for the development of prototypes for several years, and it has begun to find its use in the world of manufacturing. Digital technology and 3D printing have significantly elevated the rate of success in dental implantology using custom surgical guides and improving the quality and accuracy of dental work.

Available via license: CC BY-NC-ND 3.0

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Journal of Interdisciplinary Medicine 2017;2(1):50-53

CORRESPONDENCE

Alin-Gabriel Gabor

P-ța Eftimie Murgu nr. 2

300041 Timișoara, Romania

Tel: +40 766 245 567

E-mail: gabor.alin30@gmail.com

ARTICLE HISTORY

Received: 27 February, 2017

Accepted: 18 March, 2017

Digital Dentistry —

3D Printing Applications

Cristian Zaharia, Alin-Gabriel Gabor, Andrei Gavrilovici, Adrian Tudor Stan, Laura Idorasi, Cosmin

Sinescu, Meda-Lavinia Negruțiu

Faculty of Dental Medicine, “Victor Babeș” University of Medicine and Pharmacy, Timișoara, Romania

ABSTRACT

Three-dimensional (3D) printing is an additive manufacturing method in which a 3D item is

formed by laying down successive layers of material. 3D printers are machines that produce

representations of objects either planned with a CAD program or scanned with a 3D scanner.

Printing is a method for replicating text and pictures, typically with ink on paper. We can print

dierent dental pieces using dierent methods such as selective laser sintering (SLS), stereo-

lithography, fused deposition modeling, and laminated object manufacturing. The materials

are certiﬁed for printing individual impression trays, orthodontic models, gingiva mask, and dif-

ferent prosthetic objects. The material can reach a ﬂexural strength of more than 80 MPa. 3D

printing takes the eectiveness of digital projects to the production phase. Dental laboratories

are able to produce crowns, bridges, stone models, and various orthodontic appliances by

methods that combine oral scanning, 3D printing, and CAD/CAM design. Modern 3D printing

has been used for the development of prototypes for several years, and it has begun to ﬁnd

its use in the world of manufacturing. Digital technology and 3D printing have signiﬁcantly el-

evated the rate of success in dental implantology using custom surgical guides and improving

the quality and accuracy of dental work.

Keywords: 3D printing, digital dentistry, dental materials, bone augmentation

CLINICAL UPDATE DENTAL MEDICINE // RADIOLOGY

DOI: 10.1515/jim-2017-0032

INTroDUCTIoN

Over the past 30 years, 3D printing and prototyping has gained popularity with-

in the profession and among patients alike. It has provided comfort and better

quality of restoration to dentists. Moreover, dental restorations, which are being

produced through rapid prototyping, are more adaptive and faster in produc-

tion compared to the restorations created by dental technicians. is review ar-

ticle highlights the history and current technologies related to 3D printing.

HISTorY oF 3D PrINTING

3D printing has been used increasingly since the 1980s. In 1983, Charles Hull

printed, for the rst time, a three-dimensional object. He created the rst 3D

printer that used the technique of stereolithography, as well as the rst program

Cristian Zaharia • P-ța Eftimie Murgu nr. 2, 300041

Timișoara, Romania, Tel: +40 770 278 137

Andrei Mihai Gavrilovici • P-ța Eftimie Murgu nr. 2,

300041 Timișoara, Romania, Tel: +40 256 204 400

Adrian Tudor Stan • P-ța Eftimie Murgu nr. 2, 300041

Timișoara, Romania, Tel: +40 256 204 400

Laura Idorasi • P-ța Eftimie Murgu nr. 2, 300041

Timișoara, Romania, Tel: +40 256 204 400

Cosmin Sinescu • P-ța Eftimie Murgu nr. 2, 300041

Timișoara, Romania, Tel: +40 256 204 400

Meda-Lavinia Negruțiu • P-ța Eftimie Murgu nr. 2,

300041 Timișoara, Romania, Tel: +40 256 204 400

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51Journal of Interdisciplinary Medicine 2017;2(1):50-53

for virtualization. ey received increased attention in elds

such as architecture due to the increased potential in the di-

rect construction of parts, aeronautics because of the ease of

making various small parts used in spacecra construction,

and technical subassemblies used in telecommunications

domain. eir use in areas that require millimetric preci-

sion, has drawn the attention of specialists in general medi-

cine, who started to implement it since the 1990s.1

3D modeling technologies and techniques are develop-

ing due to the increased popularity of 3D printers.2 Among

additive manufacturing techniques, dimensional printing

is a relatively new technique that oers the possibility to

produce a variety of geometrical pieces using various ma-

terials in the form of powder and binder.3

In prosthetic treatments, computerized scanning sys-

tems and 3D printing systems have come largely to replace

traditional techniques for producing prosthetic works.4,5

e applications used in the development of 3D printed

parts use mostly technology for manufacturing various

mechanical parts, and special computer programs that

contain libraries of objects are needed to achieve design

pieces.6 Dental work patterns can be imported by scanning

various prosthetic elds or using computerized imaging

results (cone beam computed tomography). Dentistry is

familiar with the CAD/CAM technique.7 e new tech-

niques of making prosthetic restorations largely eliminate

the help given by dental laboratories.8

3D PrINTING TECHNoLoGIES

USED IN DENTAL MEDICINE

3D printing technologies used in dentistry include, among

others, selective laser melting, stereolithography, fuse de-

position modeling, and digital light processing.

Selective laser melting

Making metallic frameworks by selective laser melting tech-

nology is one of the most promising directions for solving

various problems encountered during casting alloys.9 Selec-

tive laser melting is a technique of layer by layer addition

that generates 3D pieces by strengthening selective and suc-

cessive layers of powder material, one above the other, using

heat generated by a computer-controlled laser radiation.10

Stereolithography

e most popular rapid prototyping technology is ste-

reolithography, a device invented by Charles Hull in the

1980's. is device was the rst commercially available

printer for rapid prototyping. e principle is based on

a photosensitive monomer resin, which forms a polymer

and solidies when exposed to ultraviolet (UV) light. e

reaction created by UV light takes place only on the sur-

face of the material.11

Fuse deposition modeling

e 3D printer uses a computer-aided model or scan in-

formation from which it extrudes and deposits melted

thermoplastic polycarbonate, in a layered fashion, to build

objects from bottom to top. e layers of melted plastic

instantly combine with each other, thus making very com-

plex parts that are easy to produce. e resulting aspect of

the nished object can be used in combination with sev-

eral materials such as acrylic or wax.12

Digital light processing

A projector light source is curing the liquid resin layer by

layer. e object is constructed on an elevating platform.

e layer is created upside down.13 e polymer is layered

pending the object is constructed, and the residual liquid

polymer is drained o.14

USES oF 3D PrINTING IN DENTISTrY

Oral surgery

Anatomical models made using rapid prototyping meth-

ods are a novel approach to surgical planning and simu-

lation. Such methods allow the replication of anatomical

items, including three-dimensional physical models of the

skull or other structures that allow the surgeon to obtain

an overview of complex structures before surgery. e mi-

gration from a visual environment to one that allows both

visual and touch interactions introduces a new code called

“touch to comprehend”.15

Chemical data indicate that rapid prototyping helps to

minimize the risks that might occur during surgery. 3D

printing techniques can be used in areas such as oral sur-

gery — by making surgical guides and conducting various

blocks to augment bone defects, and for learning modules

— to create mandibles and jaws that can be easily showed

to the students.16

Implantology

e utilization of tooth implants has rapidly evolved with-

in the last 20 years. Studies in the eld of oral implantol-

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52 Journal of Interdisciplinary Medicine 2017;2(1):50-53

ogy led to predictable restorative options both for patients

that are partially or totally edentulous. Positioning the

implant in improper locations has the eect of decreas-

ing predictability of the implant-supported prosthesis.17

e use of 3D printing technology has gained popularity

in dental implantology due to the introduction of guide-

lines of the surgical procedure to insert a dental implant.18

Rapid prototyping techniques allow industrial or custom-

ized manufacturing of 3D objects by using data taken from

a computer.19

3D printers can print bone tissue tailored to the re-

quirements of the patient, and can act as biomimetic

scaolds for bone cell enhancement and tissular growth

and dierentiation.20 In bone regeneration procedures,

novel 3D printed alginate-peptide hybrid scaolds can

also be used. Studies indicate that the alginate-based scaf-

folds provide a stable environment for the growth of stem

cells.21

We can create composite powders that can be printed

into scaolds. Calcium phosphate (CaP) powders can be

mixed with a 3D printing (3DP) powder based on calcium

sulphate (CaSO4), and the scaolds can also be used as

bone augmentation material.22

Maxillofacial prosthesis

e absence of parts of the external ear can be caused by

congenital disorders or can be acquired. When trying to

restore these missing parts with prosthetic materials, the

prosthesis should be customized for a better understand-

ing of its part in the complex. When defects are unilateral,

it is best to scan the opposite side and restore the aected

side by duplication. Besides ears, scientists have managed

to print cartilage and blood cells.22,23

Prosthodontics

Custom trays can be manufactured from computerized

scans of impressions/models and printed, or can be cre-

ated with readily available materials. ere are two meth-

ods that are used for the development of study models for

working in a virtual setting. e initial method includes

scanning of the impression and transferring it into a pro-

gram. e second method consists in taking the impres-

sion with a stock or semi-custom tray and pouring the

model in stone. e stone prototype can be scanned or

used directly in the manufacturing protocol. If needed,

the study prototype can be replicated with duplicating

hydrocolloid or printed, provided that a good quality

scan is present. 11

ADVANTAGES AND DISADVANTAGES

oF 3D PrINTING

If we compare the advantages of 3D printed restorations

with conventional or CAD/CAM restorations, 3D print-

ing restorations will surely be placed on top. ey provide

the possibility of high quality restorations with quick and

easy fabrication. e quality of these restorations has been

demonstrated by several studies, although cost is still a ma-

jor issue. e disadvantage of stereolithography and digital

light processing is that they are available only with light-

curable liquid polymers and the support materials must be

removed. Also, resin is messy and can cause skin irritation,

and it could also cause inammation by contact and inhala-

tion. Also, they present a limited shelf and vat life and can-

not be heat-sterilized, while being a high-cost technology.

e disadvantage of selective laser melting is that it is an

extremely costly technology and a slow process.

CoNCLUSIoN

By further research and technological advances, rapid pro-

totyping will become a widely used method for 3D recon-

structions in the dental laboratory. Nonetheless, even aer

all the technological developments in 3D printing, these

methods cannot act as substitutes for the classical tech-

niques that have been established in dental manufacturing.

Correspondingly, the evidence presented in this manu-

script calls for involvement to match the irreplaceable tal-

ent, skill, and knowledge of the dental technician.

ACKNoWLEDGEMENT

is research was partially supported by the PhD

grant of the ”Victor Babeș” University of Medicine and

Pharmacy of Timișoara — 3712/01.10.2015 (contract

no.11521/01.10.2015).

CoNFLICT oF INTErEST

Nothing to declare.

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Dec 2021

Introduction. Arterial hypertension is one of the main risk factors for the development of cardiovascular diseases. Drug treatment of arterial hypertension is associated with a number of difficulties: often requires combination therapy, also a possible change in either dosages or drugs during treatment during the patient's life. Three-dimensional printing allows to create individual medicines on-demand. Aim. Study suitability of Kollidon® VA 64 as a matrix-polymer for the preparation of immediate release ramipril printing tablets. Materials and methods. Substance: ramipril; excipients: Kollidon® VA 64, Kollidon® CL-F, Soluplus®, PEG 1500, sodium carbonate anhydrous, Poloxamer 188, sodium stearyl fumarate, mannitol; reagents: hydrochloric acid, acetonitrile for ultra-HPLC, sodium octanesulfonate for HPLC, orthophosphoric acid 85 %, sodium perchlorate analytical grade, triethylamine, standard: ramipril USP (№1598303). Ramipril filaments were prepared by hot melt extrusion on the extruder Haake™ miniCTW (Thermo Fisher Scientific). The tablets were printed on a hand-made 3D printer. The printlets were studied for friability and hardness. Uniformity and quantitative determination of ramipril and impurities in tablets and filaments were determined by high performance liquid chromatography on a Shimadzu Prominence LC liquid chromatograph. Stability of ramipril was studied on a DSC 3+ Mettler Toledo by differential scanning calorimetry. Also, the stability of ramipril was determined by the Raman spectroscopy on an analytical system ORTES-785TRS-2700. Results and discussion. Ramipril filaments with a diameter of 1.75 mm were obtained by melt extrusion at a temperature of 105 °C. They were homogeneous in quantitative content of the active substance. From the resulting filaments, tablets were printed in five configurations with three filling densities: 30 %, 50 % and 100 %. Degradation of ramipril in filaments and tablets is not observed. The melting point of the selected mixture is lower than the melting point of matrix-polymer. It makes possible to lower the processing temperature. Tablets with 100 % filling provide an immediate release of ramipril. Conclusion. Kollidon® VA 64 is suitable as a matrix-polymer for the development of immediate release ramipril printlets. Kollidon® VA 64 provides the necessary physical and processing properties of the filament required for FDM printing.

3D printing in dentistry

Article

Full-text available

Dec 2015

3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

Clinical Applications of Digital Dental Technology

Article

Dec 2022

Three-dimensional printing and oral medicine

Article

Apr 2017

M Hu

After 30 years of development, three-dimensional printing technology has made great progress, and the model and surgical guide have been clinically applied. The three-dimensional printing of titanium and other metal prosthesis and dental crown after adequate research will be applied clinically, and three-dimensional bioprinting and related biological materials need further study. Three-dimensional printing provides opportunities for the development of oral medicine, which will change the way of clinical work, teaching and research. The dentists should integrate multi-disciplinary knowledge and understand the essence of new technology to meet the challenges of the era of digital medicine.

Use of intraoral scanning and 3-dimensional printing in the fabrication of a removable partial denture for a patient with limited mouth opening

Article

Mar 2017

Background and overview: When treating patients with severely limited mouth openings, it is difficult for the dentist to obtain an impression and fabricate a removable partial denture (RPD) by using traditional methods. Intraoral scanning, computer-aided design, and 3-dimensional (3D) printing have provided alternative methods for fabricating dental prostheses. Case description: The authors present a case in which they aimed to improve the efficiency and quality of fabricating an RPD framework by integrating the technologies of intraoral scanning, computer-aided design, and 3D printing. Initially, the authors reconstructed the digital cast with multiple intraoral scans. Subsequently, the authors designed the virtual RPD framework. On the basis of the virtual framework, the titanium alloy framework was fabricated by means of a 3D printing process, and the authors fitted the final RPD to the patient. Conclusions and practical implications: Unlike the traditional method, this integrated system has the potential to design a custom-made dental prosthesis and directly make an RPD framework with complicated patterns.

From 3D modeling to 3D printing: Development of a differentiated spatial ability teaching model

Article

May 2017

3D modeling technologies and related techniques are emerging core competencies due to the increasing popularity of 3D printers. Traditional methods of teaching 3D modeling mostly depend on the use of three-view diagrams to guide students in the construction of a spatial cognition. However, a lack of three-dimensional and spatial ability on the part of the learners limits the effectiveness of this type of teaching material, and instructional effectiveness is also restricted by the existing spatial ability among students. In traditional approaches to technical education, students assume a largely passive role, while instruction adopts methods that emphasize rote learning, but these approaches are in the process of being transformed. Accordingly, the present study attempts to combine the Conceive, Design, Implement, Operate (CDIO) educational framework and 3D printing-tangible teaching materials for college students to explore potential improvements in learning outcomes. Experimental results indicate that different teaching materials (three-view diagrams and 3D printed solid models) result in the development of different spatial abilities (specifically, mental rotation and spatial visualization) and learning outcomes. In addition, the use of solid models results in 3D model learning outcomes better than those achieved using traditional three-view diagrams. Inspired by theories of perception and motivation and dual coding theory, this study developed a set of differentiated spatial ability teaching models to improve learning effectiveness for 3D modeling. The results provide guidance for the development of teaching materials and models appropriate to learners’ spatial abilities.

Novel 3D Printed Alginate-BFP1 Hybrid Scaffolds for Enhanced Bone Regeneration

Article

Sep 2016
J IND ENG CHEM

In this research, novel 3D printed alginate-peptide hybrid scaffolds were explored for enhanced bone regeneration. Bone formation peptide-1 (BFP1) was loaded into the scaffolds to promote bone regeneration. The alginate-BFP1 conjugates were synthesized via a facile EDC/NHS coupling reaction and then cross-linked in the presence of calcium ions to form hydrogel networks. The dose-dependent cytotoxicity of CaCl2 was evaluated to optimize the amount of Ca²⁺ for fabrication of scaffolds. In vitro and in vivo studies indicated that the alginate-based scaffolds provided a stable environment for the growth of human adipose-derived stem cells (hADSCs) and led to a synergistically enhanced bone regeneration.

Powder-based 3D printing for bone tissue engineering

Article

Apr 2016

Bone tissue engineered 3-D constructs customized to patient-specific needs are emerging as attractive biomimetic scaffolds to enhance bone cell and tissue growth and differentiation. The article outlines the features of the most common additive manufacturing technologies (3D printing, stereolithography, fused deposition modeling, and selective laser sintering) used to fabricate bone tissue engineering scaffolds. It concentrates, in particular, on the current state of knowledge concerning powder-based 3D printing, including a description of the properties of powders and binder solutions, the critical phases of scaffold manufacturing, and its applications in bone tissue engineering. Clinical aspects and future applications are also discussed.

Rapid prototyping and stereolithography in dentistry

Article

Apr 2015

The word rapid prototyping (RP) was first used in mechanical engineering field in the early 1980s to describe the act of producing a prototype, a unique product, the first product, or a reference model. In the past, prototypes were handmade by sculpting or casting, and their fabrication demanded a long time. Any and every prototype should undergo evaluation, correction of defects, and approval before the beginning of its mass or large scale production. Prototypes may also be used for specific or restricted purposes, in which case they are usually called a preseries model. With the development of information technology, three-dimensional models can be devised and built based on virtual prototypes. Computers can now be used to create accurately detailed projects that can be assessed from different perspectives in a process known as computer aided design (CAD). To materialize virtual objects using CAD, a computer aided manufacture (CAM) process has been developed. To transform a virtual file into a real object, CAM operates using a machine connected to a computer, similar to a printer or peripheral device. In 1987, Brix and Lambrecht used, for the first time, a prototype in health care. It was a three-dimensional model manufactured using a computer numerical control device, a type of machine that was the predecessor of RP. In 1991, human anatomy models produced with a technology called stereolithography were first used in a maxillofacial surgery clinic in Viena.

Printability of calcium phosphate: Calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique

Article

May 2014
MAT SCI ENG C-BIO S

In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead. Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique. Significant improvements (p < 0.05) in the 3DP process parameters were found for CaP (30-110 μm):CaSO4 powders compared to CaP (< 20 μm):CaSO4 powders. Higher compressive strength was obtained for the powders with the higher CaP:CaSO4 ratio. Hydroxyapatite (HA):CaSO4 powders showed better results than beta-tricalcium phosphate (β-TCP):CaSO4 powders. Solid and porous constructs were manufactured using the 3DP technique from the optimized CaP:CaSO4 powder formulations. High-quality printed constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy.