2022 Volume 10 Issue 4

DIGITAL TELESCOPIC DENTURE- A VIABLE TREATMENT MODALITY OF PREVENTIVE PROSTHODONTICS: CLINICAL REPORT

Subhabrata Maiti1*, Nitesh Rai2, Ponnanna Appanna2, Jessy P3

1Department of Prosthodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai -77, Tamil Nadu, India. [email protected]

2Department of Prosthodontics, Krishnadevaraya College of Dental Science and Hospital, Bangalore, Karnataka, India.

3Department of Pedodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai -77, Tamil Nadu, India.


ABSTRACT

A telescopic denture is considered a good alternative to the conventional removable dentures as they provide better retention, stability, support, stable occlusion, decrease in the forward sliding of the prosthesis, and better control of the mandibular movements because of the proprioception feedback which increases the chewing efficiency. Well, fabricated prosthesis with good clinical and laboratory expertise and maintained with excellent care can be a successful one. The fabrication technique using advanced digital software will eliminate manual error and can make a fast technology-developed digital prosthesis. The goal of this article was to describe the importance of saving the natural remaining teeth and the fabrication of digital telescopic dentures using subtractive milling and additive 3D printing (DMLS) technology and the application of dissimilar material for a friction fit, as an alternative to the conventional prosthesis.

Key words: Telescopic denture, Digital dentistry, Over denture, CAD CAM, Digital denture, Innovation.


Introduction

The telescopic overdenture is a logical method to use in preventive prosthodontics as it plays an important role in the preservation of alveolar bone and the periodontal sensory mechanisms that guide and monitor gnatho dynamic functions [1]. The unique principle of friction fit only when they are completely seated by using a “wedging effect” made the prosthesis with high expectations [2]. This type of restoration in patients with terminal dentition allows for reducing destructive rotational and horizontal occlusal forces by directing them more axially. The quality of the prosthesis is increasing and the time taken for fabrication is decreasing day by day as we are in the era of digital dentistry. Proper handling of 3D design software and manufacturing technology (3D printing /DMLS, Milling) can reduce manual error, the demand for highly experienced technicians, and the wastage of material.

Case report

A 45year-old female patient was reported to the hospital in Bangalore, with the chief complaint of difficulty in chewing,  speech, and poor esthetics. The preliminary examination revealed that the teeth missing in the mandibular arch were 31,32,34,35,36,41,42,43,45,46 with a dentulous maxillary arch with previous existing metal-ceramic crowns. The edentulous span had a narrow knife edge ridge. A diagnostic cast was prepared and articulated following bite registration after intraoral examination and radiographic investigation.  Considering the density and the width of the available bone through CBCT (cone beam computed tomography), an implant-supported prosthesis was eliminated as a treatment option for the patient. Also the patient was reluctant to undergo any surgical procedure hence telescopic denture was chosen as a favorable treatment of choice. Diagnostic mounting revealed a class II malocclusion with unilateral crossbite with reduced vertical dimension. To establish a telescopic denture prosthesis vertical dimension of around 3mm more was needed and it was assessed by measuring extraoral anatomical landmarks (outer canthus to modulus and base of the nose to base of the chin) and facial expression during rest and occlusion. After oral prophylaxis of abutment teeth, an interim treatment acrylic partial denture was given to the patient to restore the vertical dimension at 1mm progressively each week taking the reference point of natural opposing dentition. After six weeks, the patient was very comfortable as her complete stomatognathic system was accustomed to the 3mm established vertical dimension.

Tooth preparation was done for digitally planned milled zirconia primary copings on 33,37,44 and 47. Single stage Putty relining technique using additional silicon (3M ESPE), and an initial master model was prepared for laboratory scanning, and through digital wax-up and designing,  the primary coping was obtained virtually in 3D CAD software (Figure 1). Primary Zirconia copings, planned in CAD software were fabricated on the four abutment teeth and were made parallel to each other with two-degree tapering in order to create a single path of insertion. The copings were tried along with their relationship to each other using a fit checker (GC) and radiograph (RVG). Once the accuracy was confirmed, the primary zirconia copings were temporarily stabilized using non-Eugenol cement (GC) and an over impression was made (monophase DENTSPLY) in a special tray and a second master model was obtained. This model served to be used for scanning for fabrication of the cast partial superstructure. The model along with primary coping was scanned to make the master cast for secondary coping and framework. Secondary coping along with extension( for the attachment with framework)  was designed in the 3D designing software (Figure 2). The framework was designed virtually in the software and fabricated digitally using CAD-CAM (computer-aided design and computer-aided machining); DMLS (Direct Metal Laser sintering) technology for framework and the 3D milling technology for secondary coping in order to achieve satisfactory friction lock retention. Secondary coping and the framework was welded after proper fit Checking in the patient mouth. With the help of a metal framework the jaw relation was done in a restored vertical dimension, teeth were selected, and indirect composite resin was layered on secondary metal copings attached to the framework. In the next appointment, a try-in was done to verify prosthetic fit, esthetics, phonetics, and occlusal interferences. Acrylization was done and the labial surface of the prosthesis was layered with indirect gingival composite to maintain a pink and white esthetic score (Figure 3). Final prosthesis along with the primary coping was placed in the patient's mouth using Glass ionomer cement (GC) for the cementation of the primary coping. Post insertion 24 hours, the patient was recalled and excess cement was removed and proper instruction and follow-up was explained. Patient quality of life was improved a lot which was assessed by using questionnaire-based quality of life scale and that was the real success of the clinician.

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Figure 1. a) Virtual model after laboratory scanning, b) Design of primary coping in 3D design software, c) Zirconia primary coping, d) Scanned cast after over impression along with zirconia coping  a virtual cast  for secondary coping and framework

 

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