CASE REPORT

https://doi.org/10.5005/jp-journals-10063-0136
CODS Journal of Dentistry
Volume 14 | Issue 2 | Year 2022

The Impact of Computer-aided Design/Computer-aided Manufacturing Technology on Improving the Esthetics of Our Patients: A Case Report

Ismail Hariri1, Amal El Yamani2

1,2Department of Fixed Prosthodontic, University of Mohammed V Faculty of Dentistry, Rabat, Morocco

Corresponding Author: Ismail Hariri, Department of Fixed Prosthodontic, University of Mohammed V Faculty of Dentistry, Rabat, Morocco, Phone: +2120682069847, e-mail: haririismail6@gmail.com

Received on: 24 May 2023; Accepted on: 20 June 2023; Published on: 29 September 2023

ABSTRACT

Aim: To rehabilitate the upper central incisors and left lateral incisor with full ceramic crowns using the computer-aided design/computer-aided manufacturing (CAD/CAM) technique in order to improve the esthetic of the patient.

Background: The restoration of the anterior teeth was always challenging for the dentist and the laboratory technician especially when using full ceramic restorations, which tolerate less technical errors compared to porcelain fused metal restoration. The using of CAD/CAM technology permits a more accurate esthetic and precise restoration by its possibility to scan and analyze the clinical situation in all the space planes.

Case description: The rehabilitation of fractured central maxillary incisors and lateral maxillary incisors by a full ceramic crown restoration using CAD/CAM technology.

Conclusion: A reasonable treatment plan and an adequate conception of the restoration using CAD/CAM technology along with good oral hygiene and cooperation of the patient are the keys to the success of the rehabilitation.

Clinical significance: The CAD/CAM technology by its capacity to visualize the model in a three-dimensional space is capable of manufacturing a precise and adequate restoration which improves the esthetic of our patients and also the quality of the fixed restorations.

How to cite this article: Yamani AE, Hariri I. The Impact of Computer-aided Design/Computer-aided Manufacturing Technology on Improving the Esthetics of Our Patients: A Case Report. CODS J Dent 2022;14(2):67-72.

Source of support: Nil

Conflict of interest: None

Patient consent statement: The author(s) have obtained written informed consent from the patient for publication of the case report details and related images.

Keywords: Esthetics, Case report, Computer-aided design/computer-aided manufacturing technology, Full ceramic crowns, Precision.

INTRODUCTION

Digital technology is ubiquitous in today’s world, encompassing the internet, digital devices, smart devices, and artificial intelligence. Its expansion in the 1970s gave rise to multiple dental practice management software programs that facilitate the organization of medical records.

Computer-aided design/computer-aided manufacturing (CAD/CAM) applied to dentistry is not a recent development, it was designed in 19731 and is based on two distinct phases:

Computer-aided design/computer-aided manufacturing (CAD/CAM) has significantly improved the quality of fixed prostheses.2 A study conducted in 20143 demonstrated that the marginal adaptation of prostheses manufactured using the CAD/CAM technique (48 ± 25 μm) is more precise than that of prostheses fabricated through traditional techniques (74 ± 47 μm). Presently, there are three types of CAD/CAM, direct, semi-direct, and indirect. All three involve four steps.4

The objective of this article is to showcase the positive impact of the CAD/CAM technique on improving esthetics through a case report involving the restoration of three fractured maxillary incisors (central incisors and left lateral incisors).

Fundamentals of Computer-aided Design and Manufacturing

Thanks to numerous technological advances in the field of dentistry, we can differentiate a set of so-called CAD/CAM techniques. This dental technology, derived from computer science, enables the production of dental prostheses. Within distinguish CAD/CAM, two entities can be identified, often combined but distinct:

  • CAD: By utilizing interactive computer tools (user-machine dialogue), the operator designs the virtual model, incorporating all the necessary technical specifications for the future object.

  • CAM: The automated machine tool then manufactures the object, following the technical references obtained through CAD, using either subtractive manufacturing or additive manufacturing techniques. This results in the creation of a real object, in our case, a unique dental prosthesis.

In summary, CAD/CAM can be divided into three distinct stages, as illustrated in Figure 1.

Fig. 1: The schematic principle of CAD/CAM

Entering Information

  • Computer-aided design (CAD) of the prosthetic reconstruction.

  • Computer-aided fabrication of the prosthetic reconstruction.5

CASE DESCRIPTION

A 24-year-old female patient presented to our department in October 2020 with a chief complaint of esthetic rehabilitation for her fractured teeth (Fig. 2).

Fig. 2: Photo of the initial situation of the clinical case

The patient is in good overall health and maintains satisfactory oral hygiene. Intraoral examination revealed fractured maxillary central incisors and left lateral incisors. Occlusal examination reveals a stable occlusion with harmonious contact distribution throughout the arch (class 1 occlusion). The patient reported no history of abnormal parafunction.

A radiographic examination indicated satisfactory endodontic treatments in all the teeth and a biological width of 2.04 mm was observed for all the teeth (Fig. 3).

Fig. 3: Retroalveolar radiography of root canal treatments

Treatment Plan

  • Metal post and core for all the fractured teeth (central incisors and lateral incisor).

  • Three full ceramic crowns using CAD/CAM technique to respond to our patient’s demand.

Treatment Process

The treatment process was initiated after getting the patient’s consent.

Diagnostic impressions for maxillary and mandibular arches were performed along with a wax trial in order to explain to the patient the outcome of the treatment.

Metal post and core restorations were indicated for the maxillary central incisors and the left lateral maxillary incisor due to the significant loss of coronal tooth structure. For the coronal preparation of the teeth, a shoulder with a rounded internal angle finishing line was performed, with 1 mm thickness at the buccal face, 1.2 mm at the palatal face, and 1 mm at the interproximal faces.

Any walls of the preparation <2 mm thick were reduced and all the angles were rounded to enhance the resistance of the tooth structure. After the coronal preparation, canal drilling was conducted using alternating gates and largo drills, leaving 5 mm of the apical portion of gutta-percha to preserve the integrity of the endodontic treatment.

Impression for all the metal posts and cores was then taken using the one-step double mixing technique with polyvinyl siloxane silicone as the material. Once the metal posts were received from the laboratory, a try-in was conducted to verify the marginal adaptation of the metal posts and the occlusal clearance for the ceramic crown.

After verification, the cementation of all the metal posts was achieved using glass ionomer cement modified by the addition of resin particles (CVIMAR) (Fig. 4).

Fig. 4: Cementing all the metal posts and cores by CVIMAR

Following that, the final impression was taken using the one-step double-mixture technique with polyvinyl siloxane silicone material in order to obtain the working model for further CAD/CAM technology steps (Fig. 5). The laboratory technician performed the CAD phase, which involved data acquisition through scanning the models (working, antagonist, and models in occlusion) (Fig. 6). The axis of insertion of the future reconstructions (Fig. 7), the finishing line (Fig. 8) and the design of the zirconia infrastructure (Fig. 9) were determined.

Fig. 5: Impression by the one-step double mixing technique

Fig. 6: Model scanning (working model + antagonist model + models in occlusion)

Fig. 7: Materialization of the axis of prosthetic insertion of the different abutments

Fig. 8: Determination of the finishing line of the different abutments (green dots)

Fig. 9: The conception of the zirconia infrastructure

Using the CAM software, the manufacturing machine milled the zirconia infrastructure based on the determined shape, occlusal surface, and thickness of the future restoration using specific burs (Fig. 10).

Fig. 10: Computer-aided manufacturing: placement of the prosthetic project in the appropriate disc using the CAM tool and milling the future infrastructures using specific burs

After the milling of the infrastructures, a try-in of the reconstructions was conducted to check the cervical adaptation of the zirconia infrastructures and the clearance reserved for the cosmetic ceramic. The shade for the cosmetic ceramic was also chosen during this step (Fig. 11).

Fig. 11: Try-in of zirconia infrastructures

Once the final restorations arrived from the laboratory, a final try-in was performed to evaluate occlusion, esthetics (shape, color, and position), and the reproduction of contact points with adjacent teeth (Fig. 12).

Fig. 12: Try-in of the crowns and cementation using CVIMAR

The cementation was carried out by using glass ionomer cement modified by the addition of resin particles (CVIMAR).

A follow-up examination after 6 months revealed that the patient did not experience any discomfort (Fig. 13).

Fig. 13: Follow-up after 6 months

DISCUSSION

Computer-aided design (CAD) is a technology that has revolutionized the world of dentistry allowing an improvement of the cervical precision of prosthetic restorations, time savings, more ergonomic dentistry, the ability to archive electronic documents, and improved esthetics and patient comfort, it can also enhance the properties of certain restorations, as demonstrated in the recent experimentation conducted by Bechir et al., where it was hypothesized that cobalt–chrome alloys milled using the CAD/CAM process might exhibit slightly better corrosion resistance.6

The CAD/CAM technology also affects the fatigue performance of ceramic materials, as shown in the experiment conducted by Guilardi et al.7 The results of their study indicate that the CAD/CAM milling statistically reduced the fatigue failure load and the number of cycles for failure in all the ceramic materials.

In implantology, studies have shown that CAD/CAM abutments exhibit precise finishing lines avoiding sharp edges.8 Additionally, a systematic review published in 2022 by Suganna et al., demonstrates that CAD/CAM has created new opportunities for providing high-quality dental care.9

However, esthetics do not soley depend on CAD/CAM technology but also on other parameters, including:

CONCLUSION

Currently, with the development of technologies and digital dentistry, it is possible to create fixed prostheses with a high degree of precision, allowing for the rehabilitation of both the esthetics and the function of the patient. This technology also simplifies various laboratory steps. However, a precise analysis of the clinical case and its feasibility, along with a mastery of the CAD/CAM system and good oral hygiene of the patient, are key factors in the success of these types of clinical cases.

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