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 Table of Contents  
CASE REPORT
Year : 2021  |  Volume : 15  |  Issue : 1  |  Page : 70-73

New era of digital impressions and computer-aided designing/computer-aided manufacturing technology in fixed dental prosthetics


Department of Dental Surgery and Oral Health Sciences, Armed Forced Medical College, Pune, Maharashtra, India

Date of Submission02-May-2020
Date of Decision08-Jul-2020
Date of Acceptance31-Dec-2020
Date of Web Publication09-Mar-2021

Correspondence Address:
Poonam Prakash
Department of Dental Surgery and Oral Health Sciences, Armed Forced Medical College, Pune, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/JODD.JODD_28_20

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  Abstract 


Rehabilitation of in esthetic zone with fixed dental prosthesis (FDP) is the gold standard in the field of prosthodontic dentistry. Various impression materials have been used for impression making depending upon the type of prosthesis. The fabrication of FDP using conventional technique has been followed since long time. It is an elaborate and laborious procedure involving multiple steps wherein there are the chances of error incorporation in the final prosthesis. It may lead to distortion and misfit of final prosthesis. In the present era of dentistry, digitization in the form of direct metal laser sintering, computer-aided designing (CAD), and computer-aided milling, rapid prototyping has taken over many clinical and laboratory procedures to minimize or avoid the inaccuracies. Digital impressions and CAD/computer-aided manufacturing (CAM) alleviate the use of impression materials which can undergo distortion, fabrication of working models, and various other dental laboratory procedures involved in the fabrication of prosthesis. This case report describes the fabrication of FDP using digital impressions with intraoral scanner and CAD/CAM.

Keywords: Computer aided designing/computer-aided manufacturing, fixed dental prosthesis, intra oral scanner


How to cite this article:
Singh K, Prakash P, Kumar R V, Bahri R. New era of digital impressions and computer-aided designing/computer-aided manufacturing technology in fixed dental prosthetics. J Dent Def Sect. 2021;15:70-3

How to cite this URL:
Singh K, Prakash P, Kumar R V, Bahri R. New era of digital impressions and computer-aided designing/computer-aided manufacturing technology in fixed dental prosthetics. J Dent Def Sect. [serial online] 2021 [cited 2021 Apr 18];15:70-3. Available from: http://www.journaldds.org/text.asp?2021/15/1/70/310961




  Introduction Top


Rehabilitation of edentulous area in the esthetic zone with fixed dental prosthesis (FDP) is the gold standard in the field of prosthodontic dentistry.[1] Impression making is the basic step in fabrication of any dental prosthesis. Various techniques and materials have been used for impression making depending upon the type of prosthesis. The fabrication of FDP using conventional technique is elaborate and laborious procedure involving multiple steps, namely impression making by clinician and cast fabrication, wax pattern fabrication, casting, ceramic layering by dental laboratory technicians wherein there are chances of error incorporation in the final prosthesis.[2] It may lead to distortion and misfit of final prosthesis. In the present era of dentistry, digitization in the form of direct metal laser sintering, computer aided designing and computer aided milling, rapid prototyping has taken over many clinical and laboratory procedures to minimize or avoid the inaccuracies.[3],[4]

Using such technology, i.e., digital impressions and computer aided designing (CAD)/computer-aided manufacturing (CAM) alleviate the use of impression materials which can undergo distortion, fabrication of working models, and various other dental laboratory procedures.[5] It also reduces patient discomfort, simplifies the clinical procedures, and allows better communication with the dental technician.

This case report describes fabrication of FDP using digital impressions with intraoral scanner and CAD/CAM.


  Case Report Top


A 26-year-old male patient reported to the department of prosthodontics with a chief complaint of broken upper front tooth for the past 06 months.

History of presenting illness revealed trauma to maxillary anterior teeth 06 months ago for which no dental treatment was sought. Medical history was nil contributory. He brushes his teeth 2 times a day using tooth brush and tooth paste. Patient did not give any history of chewing tobacco or alcohol consumption.

Extraoral examination revealed bilaterally symmetrical face, with square facial form and convex profile. Intra oral examination revealed root stump of maxillary right central incisor with associated periapical abscess and draining sinus. Maxillary left central incisor was discolored. Involved teeth were evaluated for vitality using electric pulp tester. Maxillary right central incisor was found to be nonvital. Radiographic examination revealed periapical radiolucency wrt root stump of maxillary right central incisor and maxillary left central incisor. On the basis of history, clinical and radiographic examination, diagnosis of Elli's Class VIII fracture of maxillary right central incisor and nonvital maxillary left central incisor was arrived at. Various treatment options such as implant-supported prosthesis and FDP were explored and explained to the patient. Patient was unwilling for any surgical intervention, so rehabilitation with FDP using maxillary right lateral incisor and maxillary left central incisor teeth as abutment following extraction of maxillary right central incisor was decided. Informed consent was obtained from the patient, and treatment procedure was divided into four phases.

Phase I comprised of oral prophylaxis and extraction of root stump of maxillary right central incisor. After healing of the extracted socket, diagnostic impressions were made using irreversible hydrocolloid impression material (Algin-Gum, India) and casts were fabricated in type III dental stone (Kalabhai. Kalstone, India). Diagnostic mounting was done.

PHASE–II consisted of endodontic therapy for maxillary left central incisor and teeth preparation of maxillary right lateral and left central incisor to be used as abutments. The teeth were prepared with shoulder finish line for zirconia restoration following all the biomechanical principles of tooth preparation [Figure 1].
Figure 1: (a) Missing maxillary right central incisor tooth (b) Tooth Preparation and Gingival tissue management

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Following teeth preparation, gingival tissue management was done with (000) gingival retraction cord (Sure cord) which provided adequate visualization and accurate recording of prepared finish line.

The prepared teeth were scanned using intra oral digital scanner (3 SHAPE TRIOS). Three scans were made; maxillary arch including prepared teeth, mandibular arch and both the arches in occlusion to record relations of prepared teeth with antagonist teeth [Figure 2].
Figure 2: (a) Intra oral scanning of prepared teeth (b) Stereolithographic images of maxillary and mandibular arches

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Recorded images in. Stl format were loaded in CAD/CAM system (AMMANGIRRBACH). It consists of three components, i.e., Ceramill map, Creamill mind. and Ceramill motion.

In ceramill map, patient and operators details were filled, and scanned files were loaded. stl files of maxillary right lateral and left central incisor were selected as abutment teeth and maxillary right central tooth was selected as pontic. Antagonist teeth were also marked and shade along with the material to be used was selected. After filling in the requisite data, we proceeded to ceramill mind.

In ceramill mind, path of insertion for the prosthesis was selected, and finish line was marked. Maxillary and mandibular arches were matched and retainer along with pontic was designed over the marked teeth. After designing, we proceeded to ceramill motion.

In ceramill motion selected Zirconia (Zolid) blank was fitted in the milling machine and command was given to mill the designed prosthesis. Milled prosthesis was then sintered in sintering machine at 1450°C for 7.5 h [Figure 3].
Figure 3: (a) Designed prosthesis on Zolid blank (b) Milling of prosthesis in ceramill motion milling machine (c) Sintering of prosthesis in sintering machine

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The sintered prosthesis was finished with Zolid green state finishing kit. The finished prosthesis was luted with Calibra esthetic resin cement (Dentsply, Caulk) [Figure 4]. Patient was recalled for the evaluation of prosthesis at 1 week, 1 month, and 6 months, and clinical marginal adaptation was found acceptable with no clinical changes in marginal gingival.
Figure 4: (a) Pretreatment (b) Sintered 3 Unit fixed dental prosthesis (c) Prosthesis in situ (d) Post treatment

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  Discussion Top


Digital impressions using intraoral scanner and fabrication of prosthesis using CAD/CAM technology is an emerging procedure in the field of dentistry.[6] Intraoral scanner is used to record the maxillary and mandibular arches along with the prepared teeth. Scanner is placed over the distal most tooth on one side, moving toward the midline and crossing over to the other side. While recording, scanner is to be kept 2 mm away from the occlusal surface. Recorded images in the form of. stl files are loaded in the CAD/CM system. CAD/CAM systems exist in two variants based on digital data sharing capacity: Open and closed.[7] In our case, we have used Ceramill system, which is an open system and consists of three components:

Ceramill map

In this system, maxillary and mandibular cast are scanned individually as well as in occlusion. Before scanning abutment, pontic and antagonist teeth are selected along with type of prosthesis to be fabricated. Shade selection for the various parts of prosthesis is also done before proceeding to the next step.

Ceramill mind

This component selects the path of insertion for the prosthesis and mark finish lines over the prepared tooth. Designing of retainer and pontic is done and the shape of the connector between retainer and pontic is decided. Matching of maxillary and mandibular arches is matched and high points shown by highlighted area are corrected.

Ceramill motion

Selected design for the prosthesis is milled in ceramill motion. Ceramill motion consists of various cutting tools and zirconia zolid blanks, out of which prosthesis is fabricated.

Ceramill also contains one sintering unit in which the milled prosthesis is sintered at various preinstalled programs for different types of prosthesis.

The above-mentioned procedure can be used for the fabrication of various other prosthesis such as inlay, on lay, copings, and custom-made post.[8]

Use of digital technology is gaining popularity for the fabrication of FDP because of the advantages of being time saving, increased comfort for patient, creating digital library, cross-infection control, and precise fitting restoration.[9],[10] Moreover, studies have revealed that prosthesis fabricated from digital impression techniques exhibit better marginal and internal fit when compared with conventional impression techniques.[11],[12]

However, there are the various disadvantages of digital technology such as high cost of the equipment, its maintenance, and skilled technicians. A well-updated laboratory with facilities of transferring the data from clinic to laboratory is also required.


  Conclusion Top


Intraoral scanners have the potential to offer excellent accuracy with more comfortable experience for the patient and efficient work flow. The evolution of digital technology has created exciting opportunities to deliver improved and precise fit restorations. Digital dentistry offers the opportunity to avoid the clinical and laboratory procedures with the impression materials and the handling limitations associated with them.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient (s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initial s will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Salinas TJ, Block MS, Sadan A. Fixed partial denture or single-tooth implant restoration? Statistical considerations for sequencing and treatment. J Oral Maxillofac Surg 2004;62:2-16.  Back to cited text no. 1
    
2.
Ahlholm P, Sipilä K, Vallittu P, Jakonen M, Kotiranta U. Digital versus conventional impressions in fixed prosthodontics: A review. J Prosthodont 2018;27:35-41.  Back to cited text no. 2
    
3.
Sun J, Zhang FQ. The application of rapid prototyping in prosthodontics. J Prosthodont 2012;21:641-4.  Back to cited text no. 3
    
4.
Miyazaki T, Hotta Y, Kunii J, Kuriyama S, Tamaki Y. A review of dental CAD/CAM: Current status and future perspectives from 20 years of experience. Dent Mater J 2009;28:44-56.  Back to cited text no. 4
    
5.
Ng J, Ruse D, Wyatt C. A comparison of the marginal fit of crowns fabricated with digital and conventional methods. J Prosthet Dent 2014;112:555-60.  Back to cited text no. 5
    
6.
Cardelli P, Scotti R, Monaco C. Clinical fitting of CAD/CAM zirconia single crowns generated from digital intraoral impressions based on active wavefront sampling. J Dent 2011;1783:1-8.  Back to cited text no. 6
    
7.
Tapie L, Lebon N, Mawussi B, Fron Chabouis H, Duret F, Attal JP. Understanding dental CAD/CAM for restorations--The digital workflow from a mechanical engineering viewpoint. Int J Comput Dent 2015;18:21-44.  Back to cited text no. 7
    
8.
Davidowitz G, Kotick PG. The use of CAD/CAM in dentistry. Dent Clin North Am 2011;55:559-70, ix.  Back to cited text no. 8
    
9.
Syrek A, Reich G, Ranftl D, Klein C, Cerny B, Brodesser J. Clinical evaluation of all-ceramic crowns fabricated from intraoral digital impressions based on the principle of active wavefront sampling. J Dent 2010;38:553-9.  Back to cited text no. 9
    
10.
Almeida e Silva JS, Erdelt K, Edelhoff D, Araújo E, Stimmelmayr M, Vieira LC, et al. Marginal and internal fit of four-unit zirconia fixed dental prostheses based on digital and conventional impression techniques. Clin Oral Investig 2014;18:515-23.  Back to cited text no. 10
    
11.
Chochlidakis KM, Papaspyridakos P, Geminiani A, Chen CJ, Feng IJ, Ercoli C. Digital versus conventional impressions for fixed prosthodontics: A systematic review and meta-analysis. J Prosthet Dent 2016;116:184-90.  Back to cited text no. 11
    
12.
Nagarkar SR, Perdigão J, Seong WJ, Theis-Mahon N. Digital versus conventional impressions for full-coverage restorations: A systematic review and meta-analysis. J Am Dent Assoc 2018;149:139-47.  Back to cited text no. 12
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4]



 

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