SEMI-DIGITAL WORKFLOW OF REMOVABLE PARTIAL DENTURE FABRICATION FOR SCLERODERMA-INDUCED MICROSTOMIA PATIENTS: TWO CLINICAL REPORTS

Şebnem Özatik^1*, Sina Saygılı², Tonguç Sülün², Canan Bural Alan²

¹Department of Dentistry Services, Vocational School of Health Services, Istanbul Bilgi University, Kuştepe, İstanbul, Turkey. [email protected]

²Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Beyazıt, İstanbul, Turkey.

ABSTRACT

Scleroderma is a chronic connective tissue disease characterized by collagenous fibrosis resulting in the hardening and contracture of the skin and mucosa. Most of the scleroderma patients develop Raynaud's phenomenon that the fingers and toes feel numb, prickly and frigid in response to cold temperatures or stress. Due to fibrosis of the skin and soft tissues, scleroderma induces microstomia that clinically represents limited mouth opening which results in difficulty both for the patients and the dentists. Limitation of lip and tongue movements, xerostomia, gastroesophageal reflux disease, myofascial pain, dysgeusia, and periodontal problems are the most common oral health issues in scleroderma patients. Prosthetic rehabilitation of patients with a small oral orifice, such as scleroderma-induced microstomia may present difficulties. Patients with microstomia often complain of an inability to insert or remove dentures. This clinical report describes the semi-digital workflow of prosthetic rehabilitation of two partially edentulous patients with scleroderma-induced microstomia. Intraoral scanning was used for impression making and models were printed using a 3D printer. Both patients received a conventional removable partial denture. Intraoral scanning can be an alternative to conventional impression-making techniques and can be used safely in patients with microstomia for impression making.

Key words: Scleroderma, Microstomia, Removable partial denture, Intraoral scan, 3d print.

Introduction

Scleroderma is a chronic connective tissue disease characterized by collagenous fibrosis resulting in the hardening and contracture of the skin and mucosa. Most of the scleroderma patients develop Raynaud's phenomenon that the fingers and toes feel numb, prickly and frigid in response to cold temperatures or stress. Due to fibrosis of the skin and soft tissues, scleroderma induces microstomia that clinically represents limited mouth opening which results in difficulty both for the patients and the dentists. Limitation of lip and tongue movements, xerostomia, gastroesophageal reflux disease, myofascial pain, dysgeusia, and periodontal problems are the most common oral health issues in scleroderma patients. Most scleroderma patients develop Raynaud's phenomenon that the fingers and toes feel numb, prickly, and frigid in response to cold temperatures or stress. Due to fibrosis of the skin and soft tissues, scleroderma induces microstomia that clinically represents limited mouth opening which results in difficulty both for the patients and the dentists [1-8].

Prosthetic rehabilitation of individuals that have limited oral cavity, such as scleroderma-induced microstomia may present difficulties [1, 9-11]. individuals suffering from microstomia presents a complaint of an inability t or reo located or to remove dentures [1-10, 12, 13]. All prosthetic procedures can challenge especially impression making in microstomia patients. Therefore, the techniques used in taking impression requires modification considering it’s not possible to employ the use of any stock impression trays [1-10, 12, 13]. Previously, many impression making techniques using sectional impression trays have been successfully applied [6-10, 12, 13], the most suitable technique of providing a  preliminary impression for a the individual that have microstomia is not yet clear [9, 10, 12-15]. The choice of more practical method is up to the dentist;s skills and preferences [9, 10].

Recently, the use of analog impression-taking methods trends shifted towards digital technologies in daily routine prosthetic dental practice. Today, impression making, design, and fabrication of dental restorations using computer-aided technologies are easily accessible [1]. Computer-aided digital technology provides not only less time but also accurate, repeatable, and easily feasible fabrication on chairside and laboratory procedures [16]. In this digital revolution, the involvement of intraoral scanners plays an enormous role in denture fabrication with the elimination of tray selection and/or adaptation, cross-infection, and laboratory transfer of the impressions as well as the necessity of high-quality working models [17]. Computer-aided design and computer-aided manufacturing (CAD/CAM) in tooth- or implant-supported fixed prosthodontics are well studied [17-22] through the use of digital techniques on partial or complete denture production has been limited [11, 23]. The dynamic movements of soft edentulous tissues and dispersed reflection of saliva on soft tissues lead to unpredictable results for digital impressions to consider them successful [15].

In patients with scleroderma-induced microstomia, the use of CAD/CAM technologies might be clinically easier to record the denture seating area rather than the use of conventional analog methods with sectional resin trays.

This clinical report presents the semi-digital workflow of removable partial denture (RPD) treatment of two cases with microstomia.

Clinical reports

Case 1

A 37- year old female patient was referred to the Department of Prosthodontics, Faculty of Dentistry of Istanbul University for RPD fabrication. The patient’s chief complaints were reduced function and inability in chewing due to missing teeth.

The patient’s medical history revealed that she was diagnosed with scleroderma when she was 29 years old. Scleroderma was not diagnosed in her family.

Extra-oral examination revealed changes in the facial skin. The skin present on the facial was smooth and tight, and a lack of normal animation lines leading to a mask-like appearance (Figure 1). The patient's hands had sclerodactyly (Figures 2a and 2b) that is specific to scleroderma. Intra-oral examination revealed that the patient had bilateral posterior missing teeth in the mandible (Kennedy Class II, modification 1). Soft tissue examination indicated extremely thin alveolar mucosa and fibrotic lips.

A panoramic radiograph (Figure 3) revealed only periodontal ligament widening in most of the teeth with no significant periapical pathology. The vertical dimension of occlusion seemed appropriate. The patient had a diminished mouth opening of around 25 mm (Figures 4a and 4b) (Severe microstomia (maximal mouth opening ≤ 30 mm) was identified based on the the criteria provided by Naylor et al. [24]. The salivary flow seemed to be reduced. The oral health status was good, and  before impression processes, oral cavity was examined to check for the need of any tooth recontouring. The remaining teeth, which were planned to receive retainers, had naturally occurring undercuts and guide planes on the enamel surface.