From practitioner to practitioner - ZZI 01/2017

Dental implant rehabilitation of a patient with Down syndrome – interdisciplinary workflow

Introduction: Implant-supported prosthetic restorations exhibit greater patient satisfaction compared to removable prosthetic restorations. Systemic diseases such as Down syndrome can affect the treatment planning and therapy. Typical oral manifestations of this syndrome include macroglossia, dysplasia of maxilla, malocclusion of the teeth, crossbite, shortened roots and anterior open bite.

Material and methods: This case report describes therapeutic treatments of implant surgery and prosthetic rehabilitation in a patient with Down syndrome using digital treatment concepts.

Results: A complex treatment with dental implants in combination with a prosthetic restoration can be successfully carried out at a Down syndrome patient.

Discussion: It has been shown in this case study, the digital workflow and in particular digital impressions can facilitate treatment procedures in compromised patients.

Keywords: dental implants; implant prosthetics; digital impression; Down syndrome

Cited as: Theisen K, Lorenzoni M: Dental implant rehabilitation of a patient with Down syndrome – interdisciplinary workflow. Z Zahnärztl Implantol 2017; 33: 56–65

DOI 10.3238/ZZI.2017.0056–0065

Introduction

Down syndrome is the most frequently occurring chromosomal syndrome in neonates and the most frequent genetic reason for mental retardation [12]. It is a genetic disorder caused by the presence of all or part of a third copy of the complete chromosome 21. This syndrome is therefore also typically known as trisomy 21.

In 2013 approximately 10.2 million people with a manifested handicap were living in Germany, thus corresponding to 13 % of the total population [20]. At present precise data on the frequency of patients with Down syndrome cannot be found in current literature. According to an article published in 2011 about 60,000 persons with Down syndrome live in Great Britain [22].

Typical physiognomic and oral symptoms of the Down syndrome are multifaceted and include diverse manifestations. Macroglossia, dysplasia of maxilla, malocclusion of the teeth, crossbite, shortened roots and anterior open bite are found [16, 17]. Compared to the average population showing in 1–9 % the dental aplasia of at least one permanent tooth (with the exception of the third molars) [4], agenesis is a frequent symptom amongst Down syndrome patients. McMillan und Kashgarian report of an agenesis prevalence of 48 % [11], Orner of 53 % [14].

Further characteristics are a reduced dental melt and dentin strength in permanent dentition [5, 25] and hypocalcification [11, 14].

Down syndrome patients, compared with patients with or without mental retardation, exhibit a 60–100 % prevalence rate for periodontal diseases [1]. The occurrence of plaque-induced gingivitis can be raised by genetic combinations with a similar plaque accumulation [21]. The reason for the degeneration of tooth-supported structures is thus not exclusively insufficient oral hygiene [15], but moreover a generic disposition and immunological dysfunction are responsible for such a development [7, 24].

Contraindications for inserting dental implants include a variety of the symptoms, such as macroglossia, bruxism, and restricted ability to ensure oral hygiene or parafunctions. The faulty communication can also lead to non-observance of postoperative instructions. In the case of immediate treatment excessive stress may arise and favour a failure of the implant [23]. In various studies it is therefore discussed whether implants for this group of patients represent a promising therapy option. It was shown that Down syndrome patients have a reduced bone density in comparison with the average population which is most probably due to muscular hypotension [2, 3]. Ekfeldt et al. report of a 5- to 10-year survival rate of implants corresponding to 85.8 % in patients suffering from neurological and congenital impairments [8]. Clear advantages are seen in this group of patients by avoiding removable prostheses [13, 18].

According to Sadie et al. there are no universal treatment methods for all patients with or without Down syndrome so that a therapy should be aligned to the individual case taking all influencing factors into consideration [22]. Access to dental treatment is essential for people with Down syndrome and should be performed adopting a non-discriminating approach [9].

Case report

Diagnosis

The patient (27 years of age, Down syndrome) presented within the scope of an interdisciplinary consultation at the Medical University Graz, Division of Oral Surgery and Orthodontics (Austria). She suffers from mental retardation on the grounds of her underlying disease, is, however able to speak and perform simple daily tasks. The patient lives with her family and works at a special establishment for handicapped persons. No other physical diseases have been diagnosed. Tooth-maintaining measures were performed in the past at larger intervals.

The clinical intra- and extra-oral examination reflects symptoms which are typically seen in patients with Down syndrome. Insufficient oral hygiene and the resulting raised accumulation of plaque with loss of the periodontal attachment as well as moderate gingivitis were diagnosed. In addition, hypoplasia within the area of the midface and a visible macroglossia were identified. In addition the patient exhibited a hypersensitivity in the area of the palate triggering an excessive faucial reflex when gently touched besides hypersalivation which has already been described in the case of Down syndrome patients [10].

On the grounds of agenesis the following teeth were missing at the point of this initial prosthetic consultation: 18, 28, 35, 43. Additional missing teeth 14, 16, 38, 45, 48 (Fig. 1–3). Radiological imaging (orthopantomogram, OPG, Fig. 4) revealed teeth in regio 13, 23 and an apical lesion at tooth 46 due to insufficient tooth root treatment. The clinical and instrumental function analysis reflected a craniomandibular dysfunction as well as an overbite of 2 mm (enlarged sagittal plane) and an overjet of 2 mm on the right. The anterior tooth region of the mandibula reflects a marginal mobility (Miller Class I). Shortened tooth roots are characteristic and represent a frequent symptom of the underlying disease.

Therapy

In order to achieve a stable occlusal situation prosthetic-restorative treatment is indicated. Possible abutment teeth are prognostically vacant for non implant-retained prosthetic treatments. Partly prosthetic treatment with a removable prosthetic restoration is intolerable for the patient due to macroglossia and passive tongue pressure. This complies with Scully and Cawson who describe removable prosthetic restorations as problematic [18].

A functional masticatory rehabilitation is guaranteed by implant-supported rehabilitation with single-tooth crowns. In order to ensure sufficient primary and secondary stability 4 implants were planned in the maxilla taking the existing bone situation into account (regio 16, 14, 13, 23) and 2 implants in the mandibula (regio 35, 45), each of which were to be provided with implant-supported single crowns. Therapy planning comprised the integration of remaining teeth into the prosthetic concept by prosthetic-restorative treatment with individual crowns in 11, 12, 15, 21, 22, 24, 25, 26 and an endocrown in regio 46 as well as an onlay in regio 36.

For Down syndrome patients deficient cooperation in treatment, fear, lacking acceptance of the dentist and restricted tooth and oral hygiene are characteristic. The treatment concept therefore initially focused on implementing confidence-building measures and familiarising the patient with dental procedures before implementing digital implant planning.

The patient’s relatives were involved in each individual treatment step to enhance the patient’s confidence in the team. Microbial dental plaque was regularly removed to improve oral hygiene and to familiarise the patient with the dental instruments. Routine recalls at close intervals led to a higher acceptance of dental treatments on the part of the patient.

After having ensured a sufficient willingness to cooperate on the part of the patient due to the confidence-building measures, the revision of tooth 46 with following endodontic therapy was performed as a preimplantological treatment. This complication-free intervention exhibits that the patient had the necessary tolerance for the upcoming surgical intervention, even without general anaesthesia or sedation.

Surgical and prosthetic therapy

In order to align the implant positions to ensure an optimum final prosthetic treatment, backward planning is performed. 3D planning and operative implementation as well as later treatment require teamwork between the surgeon, prosthetic specialist and dental engineer. For the purpose of 3D planning digital volume tomographs (DVT, Planmeca ProMax) were performed using the NobelClinician Planning Software (Version: NobelClinician 2.3, Nobel Biocare Services AG, Zurich, Switzerland) for the maxilla and mandibula (Fig. 5).

Due to the insufficient aesthetic and functional situation a wax-up was necessary. This was produced in the laboratory. By means of optical scan a situation model was generated in the lab and read into the planning data set for 3D planning. In consideration of key anatomical structures the implant positions and angulations were planned (NobelClinician, Nobel Biocare). The implant lengths and diameters as well as angulations were determined and the implants (GC Aadva) ideally positioned in 3D planning (regio 13: ø 5.0 mm/length 12 mm; regio 14: ø 4.0/14; regio 16: ø 4.0/12; regio 23: ø 3.3/12; regio 35: ø 5.0/12; regio 45: ø 5.0/12). As sufficient bone material was available in the complete maxilla and mandibula, no augmentative measures were required.

After completing 3D planning a tooth-supporting pilot drill guide (NobelClinician, Nobel Biocare) for a 2-mm pilot drill was produced and used for dental surgery. The pilot drill guide was positioned on the remaining teeth, the correct position controlled and the 2-mm pilot drill performed (Fig. 6, 7). Due to the high level of cooperation on the part of the patient, it was possible to perform the intervention with local anaesthesia. The implants were inserted with primary stability and with sufficiently high torque (> 35 Ncm) in compliance with 3D planning. The initial primary stability is supported by an individually adapted drill protocol taking the various bone qualities into account in the case of the implant system used (GC Aadva).

The control X-ray exhibits regular inserted implants (Fig. 8) with regard to position and angulation. The patient received antibiotic and antiphlogistic medication prior to and after surgery. Seven days after surgery the stitches were removed. In the standard healing phase of 3 months routine hygiene consultations took place. During this phase the remaining teeth in region 11, 12, 21, 22 were used for temporary treatment in order to determine the patient’s tolerance with regard to function and aesthetics (manufactured: BSI Zahntechnisches Laboratorium, Guntramsdorf, Austria). The temporary dentures in the front teeth area, maxilla, were used to evaluate the patient’s requirements and expectations and serve as functional and aesthetical prototype. After the healing phase the implants were exposed without any complication within the scope of outpatient treatment.

The teeth in regio 11, 12, 15, 21, 22, 24, 25, 26, which required prosthetic-restorative treatment in the concept, had to be prepared and impressed in several sessions, as the patient was not able to tolerate treatment sessions lasting longer than approx. 60 minutes in each case. A special challenge was to produce the impression due to the unusual impression mould as well as the excessive faucial reflex. In order not to endanger the patient’s confidence in the dental team, the process of taking impressions was carried out in several sessions with interim interruptions. The temporary dentures were incorporated with cemented plastic crowns for these teeth.

Clinical and radiological check-ups were performed at regular intervals. In 2 of these check-ups the patient presented without her temporary dentures which she had lost. The patient subjectively stated that she did not feel any pain at the vital teeth, which coincides with the general disease situation.

For the supra-constructions (13, 14, 16, 23, 35, 45) a model scan with following transmission of data to the GC Tech Millingcenter (Belgium) requiring precise milling was performed. Based on these data the one-piece screw-retained chromium-cobalt crowns were manufactured in the laboratory (Neubauer & Ebenberger zahntechnisches Labor GmbH, Graz, Austria) and blended with GC MC ceramic. The material selected in combination with milled crowns offers a higher stability and resistance to stress in comparison with full-ceramic supra-constructions. Due to the patient’s existing parafunctions the risk of fractures is visibly reduced. In comparison with a cemented treatment the screwed supra-constructions are additionally easier to remove and clean in later recalls. When inserting the supra-construction in regio 23 the patient suffered a tussive irritation and swallowed this supra-construction, so that it had to be produced anew. In further consultations the crowns were inserted in regio 11, 12, 15, 21, 22, 24, 25, 26 (e.max, Ivoclar Vivadent, Liechtenstein) (Fig. 9–11). Here, too, it was noticed that the patient initially had difficulty in tolerating unusual treatment steps, but accepted the treatments after adapting.

The teeth in regio 36, 46 were filled with temporary filling material. It was planned to insert one onlay (regio 36) as well as one endocrown (regio 46). Due to the patient’s excessive faucial reflex the dental team refrained from making conventional impressions. Instead a digital intraoral scan (Cerec Omnicam, Sirona Dentsply) was performed (Fig. 12, 13), which the patient tolerated without any problems. No faucial reflex or subjective impeded breathing were registered. According to the scan data the dental restorations (36, 46) were manufactured in hybrid ceramic (Vita Enamic, VITA Zahnfabrik, Bad Säckingen, Germany) on the chair side and positioned intraorally with RelyX Unicem (3M ESPE Dental Products, St. Paul, USA).

Figure 14 exhibits the final radiological diagnosis after inserting the dental restorations in regio 11, 12, 13, 14, 15, 16, 21, 22, 23, 24, 25, 26, 35, 36, 45, 46 as well as the clinical end situation (Fig. 15, 16).

The patient and her relatives were highly satisfied with the aesthetic appearance and functionality of the new dental prosthesis.

Summary

As in the case of other systemic diseases Down syndrome patients suffer from impaired oral health. Due to the increased life expectancy of impaired persons [19] in the last decades, it is among others, important that these patients are granted discrimination-free access to medical and dental therapies. Down syndrome patients with or without mental retardation should be able to benefit from high-quality treatments in aesthetic and functional aspects [9].

Based on the case report it is shown that a complex therapy with dental implants in combination with a prosthetic restoration can be performed at a Down syndrome patient.

The risk-benefit ratio shall be assessed upfront. In particular the oral symptoms of Down syndrome patients as well as their cooperation must be taken into account. Compliance can be tested during initial control examinations with an increased duration of treatments. In planning the therapy options it is also necessary to clarify whether hygiene measures can be assumed by patients with support from their social environment.

Due to increasing acceptance and willingness to cooperate among these patients in dental procedures and the positive development of oral hygiene it was possible to plan and implement a complex therapy form under primary consideration of the oral manifestations.

The shorter therapy sessions as against patients without impairments require a longer treatment period and higher personnel costs. It is furthermore necessary to adapt treatments individually to the patient’s respective constitution, thus making it difficult to plan the respective appointments in the long-term.

According to Holthaus a treatment in general anaesthesia or sedation is often required and general anaesthesia is administered in 40 of 100 cases [6]. By gently familiarising the patient with therapy procedures it was possible to omit anaesthesia despite the complexity.

In comparison between conventional impression technique (material: Polyether, Impregum Soft, 3M ESPE) and digital impression (Cerec Omnicam, Sirona Dentsply) it was shown that the digital scan is complication-free and required no adaptation phase. In contrast to conventional impression techniques the scan can be interrupted and continued at any time. Faulty scans which may arise by a moving tongue, coughing reflex, unrest etc. during recording can be subsequently deleted and do not play a role in calculating the digital impression. In our opinion, a digital intraoral scan should thus be given preference in particular in the case of impaired persons.

Routine recalls at close intervals are also essential to guarantee long-term success for the purpose of monitoring oral hygiene and compliance with the instructions. According thereto it has been planned to carry out a control and hygiene recall once in two months. Screw-supported supra-constructions should be given preference in this group of patients, as these, in comparison with the cemented variant, are easier to remove in the regular hygiene intervals, if the need arises.

The high costs for the selected therapy form are justified by the positive effect on the patient’s personality. Food intake has a high significance in the case of Down syndrome patients. By a firmly positioned implant prosthesis rehabilitation it is possible to visibly improve the masticatory function and thus enhance the quality of life of these patients.

The use of dental implants and digital impression techniques in Down syndrome patients has hardly been scientifically investigated. At present, there are no systemic examinations in this respect. Guidelines and protocols for the treatment of mentally retarded patients should be established. As a result risks and possible complications in the preliminary phase and during treatment could be more easily assessed.

Acknlowledgement: We would like to thank GC Austria GmbH for their generous support and provision of material. In addition thereto, we would like to thank the dental engineer Mr Robert Neubauer (Neubauer & Ebenberger zahntechnisches Labor GmbH, Graz, Austria) and the dental engineer Mr Rudolf Hrdina (BSI Zahntechnisches Laboratorium GesmbH, Guntramsdorf, Austria) for producing the supraconstructions and performing the prosthetic work. Without the provision of material and production of prosthetic constructions it would not have been possible to finance the selected therapy for the patient. We would like to thank Dr Elisabeth Amberger as well as the dental team of Ordination Prof Lorenzoni for their valuable cooperation and extensive commitment.

Footnote

1 Medical University Graz, Division of Oral Surgery and Orthodontics, Department of Dental Medicine & Oral Health, Graz, Austria

Übersetzung: Jacobi Übersetzungen

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