journal of prosthodontic research 59 (2015) 199–204
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/jpor
Case Report
Long term clinical outcome of dental implants placed in a patient with Singleton–Merten syndrome Reena Rodriguez a,*, Nico Hartmann a,1, Ludger Figgener b,2, Johannes Kleinheinz c,3, Dieter Weingart a,1 a
Department of Oral and Maxillofacial Surgery, Katharinen Hospital, Kriegsbergstr. 60, D-70174 Stuttgart, Germany Department of Prosthetic Dentistry, University of Muenster, Germany c Department of Cranio-Maxillofacial Surgery, University of Muenster, Germany b
article info
abstract
Article history:
Patients: Singleton–Merten syndrome is an extremely rare autosomal dominant condition
Received 22 July 2014
with less than 10 reported cases in the literature. It is characterized by abnormal aortic
Received in revised form
calcifications and dental abnormalities. The goal of this case report is to discuss the
2 March 2015
abnormal oral clinical features and the modified treatment protocol that was used in order
Accepted 26 March 2015
to achieve osseointegration of dental implants in a patient having abnormal bone density
Available online 2 June 2015
and bone turnover associated with Singleton–Merten Syndrome. Discussion: Following extraction of the remaining teeth, titanium implants (Friadent GmbH,
Keyword:
Mannheim, Germany and Straumann1, Basel, Switzerland) were placed in the upper and
Singleton–Merten syndrome
lower jaw of the patient. The upper jaw which was treated with dental implants, received a
Abnormal bone quality
bar supported implant retained prosthesis and the lower jaw an implant retained telescopic
Osseointegration
prosthesis. The patient was regularly followed up for the past 13 years during which, clinical and radiological evaluation of osseointegration was undertaken. All the loaded implants showed clinical and radiographic evidence of osseointegration. With a follow up of 13 years after insertion of the first implant, the patient reported functioning well with no complications. Conclusion: The treatment with dental implants in the extremely rare Singleton–Merten syndrome patients is a reasonable treatment option to rehabilitate maxillofacial aesthetics and establish normal function of the jaws. # 2015 Japan Prosthodontic Society. Published by Elsevier Ireland. All rights reserved.
* Corresponding author. Tel.: +49 711 278 33 01; fax: +49 711 278 33 09. E-mail addresses: [email protected], [email protected] (R. Rodriguez), [email protected] (N. Hartmann), [email protected] (L. Figgener), [email protected] (J. Kleinheinz), [email protected] (D. Weingart). 1 Department of Oral and Maxillofacial Surgery, Katharinen Hospital, Kriegsbergstr. 60, D-70174 Stuttgart, Germany. Tel.: +49 711 278 33 01; fax: +49 711 278 33 09. 2 Albert-Schweitzer-Campus 1, Waldeyerstraße, 3048149 Muenster, Germany. Tel.: +49 2 51/8 34 70 77; fax: +49 2 51/8 34 71 82. 3 Department of Cranio-Maxillofacial Surgery, Albert-Schweitzer-Campus 1, Waldeyerstraße, 30 48149 Mu¨nster, Germany. Tel.: +49 251/83 47003; fax: +49 251/83 56960. http://dx.doi.org/10.1016/j.jpor.2015.03.003 1883-1958/# 2015 Japan Prosthodontic Society. Published by Elsevier Ireland. All rights reserved.
200
1.
journal of prosthodontic research 59 (2015) 199–204
Introduction
Singleton–Merten syndrome is an extremely rare, multisystemic disorder characterized by high anterior hairline, broad forehead, mild unilateral ptosis, and thin upper vermilion accompanied by core manifestations like aortic calcification, dental anomalies and distal limb ossification disturbances [1,2]. The exact pathophysiology is unclear due to the rarity of the disease. Less than 10 clinical cases have been reported so far in the literature. It is likely to be an autosomal dominant mutation with variable expression manifested due to an abnormal calcium metabolism and disturbed immunological functioning [2,3]. Other physical findings associated with this syndrome may include generalized muscle weakness; progressive muscular atrophy; delayed motor development and eczema. Osteoporotic phalanges and metacarpals, metatarsal bones with medullary widening are common, and may be accompanied by osteolysis of the distal phalanges [3]. Ectopic artery calcification is frequently associated with decreased bone mineral density or disturbed bone-turnover. This contradictory association is referred to as the ‘‘calcification paradox’’ Hydroxyapatite in the bone dissolves and neutralizes metabolic H (+) when the acid-base balance is above a physiological level [4,5]. Hydroxyapatite dissolves in the acidic environment, setting free Ca2+. Thus an orchestrated activation of osteoclasts increases extracellular Ca2+concentration. This causes an abnormal bone mineral density/disturbed bone turn over and concomitant calcification in the vascular smooth muscles. The use of the osseointegrated dental implant for rehabilitation of the partially and fully edentulous patients has been considered as a reliable and safe treatment option [6,7]. The predictability of the treatment outcome is dependent on the bone volume and density of the prospective recipient site. This in turn often necessitates additional bone augmentation procedures [8,9]. Studies show a positive correlation to bone health through the rehabilitation with dental implants. The ability to transfer strain into the bone which is essential for physiological functioning and remodelling, helps to maintain bone health [10]. The treatment of patients with disturbed bone metabolism as seen in osteoporosis has been subject of intense investigation in the field of dental implantology. Improvements in implant surface characteristics, design, surgical techniques and imagining technology has led to the consensus that moderate osteoporosis can be rehabilitated with long term success and predictability [11,12]. We present the clinical case of a patient with Singleton– Merten syndrome who, despite presenting with multisystem disorders including osteoporosis, was successfully rehabilitated with dental Implants.
2.
Outline of the case
A 15-year-old male patient diagnosed with Singleton–Merten syndrome presented to the University Hospital in Muenster, Germany in August 1996. This patient hails from a family in
which two other members have also been diagnosed with Singleton–Merten syndrome. They are the only three patients identified with this syndrome in Germany to our knowledge.
2.1.
Local findings
Intraoral examination revealed an abnormal mixed dentition with multiple retained deciduous teeth and missing permanent teeth which resulted in as a severe non-occlusional bite. The panoramic radiograph showed evidence of multiple impacted teeth and incomplete root development in the remaining permanent teeth. In order to establish a correct jaw relation in the horizontal and vertical aspect, acrylic bite planes were made for the posterior teeth in both the jaws (Fig. 1a). The upper incisors were restored with metal ceramic crowns and the lower anterior teeth were restored with an acrylic resin bridge spanning from #33 to #43. (both canine abutments had incomplete root development.) After four years of function the bite plane had to be replaced due to severe abrasion on the occlusal surfaces. In May 2000, teeth #11 and #21 were extracted due to poor prognosis and restored with an interim acrylic partial denture during the post-operative healing period of three months. Thereafter titanium implants were placed in relation to teeth #11(Friadent GmbH, Mannheim, Germany Frialit 3.8 mm 11 mm), #21(Friadent GmbH, Mannheim, Germany Frialit 3.8 mm 11 mm). The upper jaw was rehabilitated with a definitive implant supported screw retained prosthesis incorporating implants from teeth #11-21. In 2004, further four implants were inserted in relation to teeth #13, #14, #23, (Straumann1, Basel, Switzerland, Standard implant-Regular neck 3.3mmx11) #24 (Straumann1, Basel, Switzerland, Regular Neck-Standard implant 3.8 mm 11 mm) mm) which was restored with a partial denture spanning from #14 to # 24. In 2007, a titanium implant was placed in relation to tooth # 44 (Straumann1, Basel, Switzerland, Standard implantRegular neck 4.8 mm 10 mm) which was positioned through a retained tooth germ that was electively not removed. Due to a poor prognosis of the remaining teeth, the presence of the multiple impacted teeth, evidence of abnormal bone turn over and considering the general medical condition of the patient, two years later (2009), the patient presented to the department of Oral and Maxillofacial Surgery, Katharinen hospital, Stuttgart for further treatment. Apart from the aforementioned clinical findings, the patient also developed multiple carious lesions and chronic generalized periodontitis. It was determined that all erupted teeth were non-restorable and required extractions. Titanium Implant based restoration which necessitated the extraction of the impacted teeth was planned.
2.2.
Medical history
On examination of the medical history, it was revealed that the cardiovascular system showed evidence of progressive calcification. The condition had gradually worsened over the years and necessitated the replacement of the aortic and mitral valve. The patient also suffers from glaucoma and eczema. Furthermore the patient’s fingers and toes were
journal of prosthodontic research 59 (2015) 199–204
201
Fig. 1 – (a–d) Panoramic radiograph showing different stages of treatment: (a) teeth with generalized resorption of roots and bite planes for occlusal correction (2000). (b) Post implant surgery in the mandible when additional implants were inserted (2007). (c) 1-year post operative follow up of implants showing minimal bone loss (2008). (d) Stable bone niveau 13 years after the first implant placement (2013).
Fig. 2 – All the teeth were severely ankylosed. (a–c) Showing shortened roots and (d) the extracted mandibular teeth and restorations.
visibly shorter. He had chronic microcytic anaemia and mild depression and also complained of frequent nose bleeds.
2.3.
Surgery
The details of the surgical procedure that was undertaken in the lower jaw is as follows: The surgery was undertaken in
general anaesthesia (Propofol 1% (Disorivax 3 mg/kg/h), Remifentanil (Ultiva 0.4 mg/kg/min), and Recuroniumbromid (Esmeron 0.5 mg/kg.), and all procedure of extraoral and intraoral sterility were ensured. Each time the patient underwent surgery he was shifted from using Phenprocoumone (Marcumar1) to Heparin as the latter has a shorter half life and reduced the risk of post surgical thrombosis. Surgical
202
journal of prosthodontic research 59 (2015) 199–204
Fig. 3 – Perioperative photograph of (a) left mandibular implants insertion after extraction (b) the defects were filled with autologous bone harvested during osteotomy with a bone filter. (c) Geistlich Bio-GideW membrane placed over the defect to enhance bone regeneration.
extraction of impacted teeth/severely ankylosed teeth #85, #46, #47, #34, #75, #36, #37, #38, #55, #14, #16, #17, #53, #27, #28 were done as a first step. Fig. 2 shows the radicular and coronal portions of teeth that were extracted along with the crown and bridge restorations that were removed during the total extraction procedure. Further extraction of #35, #45 and endosseous implant placement in teeth region # 45, #46, 47, #34, #35, #36 and bone augmentation in lower jaw was done. Tooth #35 was very brittle and extracted under a microscope. It was situated in close proximity to the inferior alveolar nerve and had to be removed by multiple tooth sectioning. The implant osteotomy sites were prepared using a surgical template. In region #34, #35, #45, #47 Straumann1, Basel, Switzerland, Standard implants – Regular neck (4.1 mm 10 mm) in region#46, #36 Straumann1, Basel, Switzerland, Standard implants-Wide neck (4.8 mm 10 mm) were inserted. The lateral dehiscence was covered by bone particles obtained from the osteotomy from the bone filter. Collagen (KOLLAGEN-resorb, RESORBA Wundversorgung GmbH & Co. KG, Nuernberg, Germany) inserted into the extraction socket at for hemostasis and enhancing bone regeneration. Fig. 3 shows the intra-operative situation in the left side of the mandible where the bone defects were filled with autologous bone and covered by a collagen membrane (Geistlich Bio-Gide1, Geistlich Pharma, Wolhusen, Switzerland) membrane. Surgical wound closure was achieved by Vicryl 4-0 V5 violet (Ethicon, Norderstedt, Germany). The patient remained stationary in the hospital ward until post operative day 5 and thereafter made regular follow up examinations periodically and received provisional prosthesis. On Fig. 1(b) the panoramic radiograph shows the post surgical situation. After three months a second surgical approach was undertaken to uncover the implant placed in relation to tooth #35 and all the rest of the implants healed transmucosally and were visible in
the oral cavity. This was performed under local anaesthesia with continuous monitoring of the vital parameters using a medical monitor. (Philips IntelliVue X2 Draeger Primus, Mannheim, Germany). On Fig. 1(c) the panoramic radiograph shows uneventful healing at 1-year post implant insertion.
2.4.
Prosthodontic treatment and follow up
It was decided to fabricate a maxillary bar supported implant retained denture and a mandibular telescopic overdenture as shown in Fig. 1(d). Fig. 4 shows the occlusal view of the present clinical situation (2013) and the prosthesis at a 13 year follow up since the insertion of the first implants. Fig. 5 shows the intercuspal position of the maxillary and mandibular prosthesis in the present clinical situation (2013). The follow up consisted of oral prophylaxis quarterly along with clinical and radiological assessment of implant osseointegration.
3.
Discussion
The pathophysiology of this multi-systemic condition has not been elucidated till now. It is thought to be an autosomal dominant condition. The abnormal increased calcification seen in the aorta and the ventricles are the major medical problems in patients with Singleton–Merten syndrome. The sequelae of the progressive calcification have been the cause of death in all patients reported until date [2]. Recent research proves that bone responds to both hormonal as well biomechanical regulations. These two mechanisms are often opposite to each other. It has been shown that even when there is a relative large demand for calcium, functional loading can compete and maintain bone mass [13,14]. Osteocytes have a higher sensitivity to mechanical stimulation than osteoblasts. Bone disuse even for a short
journal of prosthodontic research 59 (2015) 199–204
203
Fig. 4 – Post surgical follow-up after 13 years showing (a) maxillary implant supported bar attachment (b) mandibular telescopic implant abutment. (c–d) Maxillary and mandibular prosthesis.
Fig. 5 – Frontal view of intercuspal position of upper and lower denture in position of the patient. Note the signs of wear from the prolonged use of the denture.
duration may rapidly induce a hypoxic state of stress in osteocytes, which when extended may lead to apoptosis. This hypoxia may be reversed by short term physiological loading, which suggests that mechanical loading at such magnitudes play a key role in osteocyte viability [15,16]. Previous studies suggest a normal bone turn over and bone formation within 87% for the mean age with normal mineralization in this patient [17–19]. Serum levels of receptor activator of
NF-kappaB and osteoprotegerin were normal [18,19]. We speculate that a decreased osteoblastic number and/function maybe responsible for the phenotype in Singleton–Merten syndrome. Feigenbaum et al. and Rutsch et al. reported a pattern of acute resorption of teeth in this patient which may have subsequently led to ankylosis. This necessitated extensive osteotomy procedures to extract the teeth. Previous studies described implant placement in contact with dental roots [12,20,21] was considered as a possible alternative approach to the standard invasive procedure that requires removal of every root fragment [22]. The implant corresponding to tooth #44 was thus positioned through the impacted and ankylosed tooth. The soft tissues and hard tissues healed uneventfully. The post operative follow up of the patient showed minimal periimplant bone loss according to the guidelines of Alberktsson and Zarb and signs of periimplantitis were absent. This case report is the first to our knowledge to report complete rehabilitation with dental implants in a case of Singleton–Merten Syndrome. Considering limited dexterity and fine motor skills of the patient, hygiene friendly prosthetic rehabilitation was chosen. Since the genetic cause of Singleton–Merten syndrome is not known, there is no specific medical test that can definitively assign the diagnosis. The diagnosis is usually based on the characteristic facial appearance of the affected individual, and on the medical and dental features. This is one of the reasons why it is important for health professionals to
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journal of prosthodontic research 59 (2015) 199–204
recognize the characteristics and consequently refer such patients for the necessary multidisciplinary treatments.
4.
Conclusion
This case report shows that Singleton–Merten syndrome patients can benefit from dental implant treatment and that they can successfully be rehabilitated to restore form, function and quality of life to the patient. Further prospective studies using implants in Singleton–Merten syndrome patients are necessary to confirm whether dental implants can be routinely used in such patients.
Conflict of interest The authors declare no conflict of interest related to this study.
references
[1] Singleton EB, Merten DF. An unusual syndrome of widened medullary cavities of the metacarpals and phalanges, aortic calcification and abnormal dentition. J Pediatr Radiol 1973;1:2–7. [2] Feigenbaum A, Mu¨ller C, Yale C, Kleinheinz J, Jezewski P, Kehl HG, et al. Singleton–Merten syndrome: an autosomal dominant disorder with variable expression. Am J Med Genet 2013;161:360–70. [3] Gay BB, Kuhn JP. A syndrome of widened medullary cavities of bone, aortic calcification, abnormal dentition, and muscular weakness (The Singleton–Merton syndrome). Radiol 1976;118:389–95. [4] Arnett TR, Dempster DW. Comparative study of disaggregated chick and rat osteoclasts in vitro: effects of calcitonin and prostaglandins. Endocrinol A 1987;120:602–8. [5] Arnett TR, Spowage M. Modulation of the resorptive activity of rat osteoclasts by small changes in extracellular pH near the physiological range. Bone 1996;18:277–9. [6] Zarb GA, Alberktsson T. Criteria for determining clinical success with osseointegrated dental implants. Cah Prothese 1990;71:19–26. [7] Fransson C, Lekholm U, Jemt T, Berglundh T. Prevalence of subjects with progressive bone loss at implants. J Clin Oral Implant Res 2005;16:440–6.
[8] ten Bruggenkate CM, van der Kwast WAM, Oosterbeek HS. Patient selection criteria in oral implantology. Int J Oral Implant 1991;2:53–60. [9] Weingart D, Strub JR, Schilli W. Kieferchirurgischprothetisches Konzept zur implantologischen Versorgung bei unterschiedlichem Atrophiegrad des zahnlosen Patienten. Z Stomatol 1992;89:137–41. [10] Clarice F, Qing Li, Wie Li, Mark T, Michael S. Prediction of mandibular bone remodelling induced by fixed partial dentures. J Biomech 2010;43:1771–9. [11] Blanchaert RH. Implants in the medically challenged patient. Dent Clin N Am 2005;42:35–45. [12] Buser D, Warrer K, Karring T. Formation of a periodontal ligament around titanium implants. J Periodontol 1990;9:597–601. [13] Marks SC, Popoff SN. Bone cell biology the regulation of development, structure and function in the skeleton. Am J Anat 1988;183:1–44. [14] Brighton CT, Sennett BJ, Farmer JC, Iannotti JP, Hansen CA, Williams JL, et al. The inositol phosphate pathway as a mediator in the proliferative response of rat calvarial bone cells to cyclical biaxial mechanical strain. J Ortho Res 1992;3:385–93. [15] Dodd JS, Raleigh JA, Gross TS. Osteocyte hypoxia: a novel mechanotransduction pathway. Am J Physio 1999;277:598–602. [16] O’Brien CA, Jia D, Plotkin LI, Bellido T, Powers CC, et al. Glucocorticoids act directly on osteoblasts and osteocytes to induce their apoptosis and reduce bone formation and strength. Endocrinology 2004;145:1835–41. [17] Rutsch F, Kehl HG, Ruf N, Vogt J, Kleinheinz J, Rauch F, et al. Eur J Hum Genet 2005;13(112):154. [18] Van Campenhout A, Golledge J. Osteoprotegerin, vascular calcification and atherosclerosis. Atherosclerosis 2009;204:321–9. [19] Zhao MM, Xu MJ, Cai Y, Zhao G, Guan Y, Kong W, et al. Mitochondrial reactive oxygen species promote p65 nuclear translocation mediating high-phosphate-induced vascular calcification in vitro and in vivo. Kidney Int 2011;79:1071–9. [20] Warrer K, Karring T, Gotfredsen K. Periodontal ligament formation around different types of dental titanium implants I. The self-tapping screw type implant system. J Periodontol 1993;1:29–34. [21] Davarpanah M, Szmukler-Moncler S. Unconventional implant treatment – implant placement in contact with ankylosed root fragments-A series of five case reports. J Clin Oral Implant Res 2009;20:851–6. [22] Davarpanah M. Reliability of the root-implant interface in unconventionally placed implants an up to 6-year followup of 23 implants covering 3 distinct clinical applications. J Clin Oral Implant Res 2009;20:916.
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/jpor
Case Report
Long term clinical outcome of dental implants placed in a patient with Singleton–Merten syndrome Reena Rodriguez a,*, Nico Hartmann a,1, Ludger Figgener b,2, Johannes Kleinheinz c,3, Dieter Weingart a,1 a
Department of Oral and Maxillofacial Surgery, Katharinen Hospital, Kriegsbergstr. 60, D-70174 Stuttgart, Germany Department of Prosthetic Dentistry, University of Muenster, Germany c Department of Cranio-Maxillofacial Surgery, University of Muenster, Germany b
article info
abstract
Article history:
Patients: Singleton–Merten syndrome is an extremely rare autosomal dominant condition
Received 22 July 2014
with less than 10 reported cases in the literature. It is characterized by abnormal aortic
Received in revised form
calcifications and dental abnormalities. The goal of this case report is to discuss the
2 March 2015
abnormal oral clinical features and the modified treatment protocol that was used in order
Accepted 26 March 2015
to achieve osseointegration of dental implants in a patient having abnormal bone density
Available online 2 June 2015
and bone turnover associated with Singleton–Merten Syndrome. Discussion: Following extraction of the remaining teeth, titanium implants (Friadent GmbH,
Keyword:
Mannheim, Germany and Straumann1, Basel, Switzerland) were placed in the upper and
Singleton–Merten syndrome
lower jaw of the patient. The upper jaw which was treated with dental implants, received a
Abnormal bone quality
bar supported implant retained prosthesis and the lower jaw an implant retained telescopic
Osseointegration
prosthesis. The patient was regularly followed up for the past 13 years during which, clinical and radiological evaluation of osseointegration was undertaken. All the loaded implants showed clinical and radiographic evidence of osseointegration. With a follow up of 13 years after insertion of the first implant, the patient reported functioning well with no complications. Conclusion: The treatment with dental implants in the extremely rare Singleton–Merten syndrome patients is a reasonable treatment option to rehabilitate maxillofacial aesthetics and establish normal function of the jaws. # 2015 Japan Prosthodontic Society. Published by Elsevier Ireland. All rights reserved.
* Corresponding author. Tel.: +49 711 278 33 01; fax: +49 711 278 33 09. E-mail addresses: [email protected], [email protected] (R. Rodriguez), [email protected] (N. Hartmann), [email protected] (L. Figgener), [email protected] (J. Kleinheinz), [email protected] (D. Weingart). 1 Department of Oral and Maxillofacial Surgery, Katharinen Hospital, Kriegsbergstr. 60, D-70174 Stuttgart, Germany. Tel.: +49 711 278 33 01; fax: +49 711 278 33 09. 2 Albert-Schweitzer-Campus 1, Waldeyerstraße, 3048149 Muenster, Germany. Tel.: +49 2 51/8 34 70 77; fax: +49 2 51/8 34 71 82. 3 Department of Cranio-Maxillofacial Surgery, Albert-Schweitzer-Campus 1, Waldeyerstraße, 30 48149 Mu¨nster, Germany. Tel.: +49 251/83 47003; fax: +49 251/83 56960. http://dx.doi.org/10.1016/j.jpor.2015.03.003 1883-1958/# 2015 Japan Prosthodontic Society. Published by Elsevier Ireland. All rights reserved.
200
1.
journal of prosthodontic research 59 (2015) 199–204
Introduction
Singleton–Merten syndrome is an extremely rare, multisystemic disorder characterized by high anterior hairline, broad forehead, mild unilateral ptosis, and thin upper vermilion accompanied by core manifestations like aortic calcification, dental anomalies and distal limb ossification disturbances [1,2]. The exact pathophysiology is unclear due to the rarity of the disease. Less than 10 clinical cases have been reported so far in the literature. It is likely to be an autosomal dominant mutation with variable expression manifested due to an abnormal calcium metabolism and disturbed immunological functioning [2,3]. Other physical findings associated with this syndrome may include generalized muscle weakness; progressive muscular atrophy; delayed motor development and eczema. Osteoporotic phalanges and metacarpals, metatarsal bones with medullary widening are common, and may be accompanied by osteolysis of the distal phalanges [3]. Ectopic artery calcification is frequently associated with decreased bone mineral density or disturbed bone-turnover. This contradictory association is referred to as the ‘‘calcification paradox’’ Hydroxyapatite in the bone dissolves and neutralizes metabolic H (+) when the acid-base balance is above a physiological level [4,5]. Hydroxyapatite dissolves in the acidic environment, setting free Ca2+. Thus an orchestrated activation of osteoclasts increases extracellular Ca2+concentration. This causes an abnormal bone mineral density/disturbed bone turn over and concomitant calcification in the vascular smooth muscles. The use of the osseointegrated dental implant for rehabilitation of the partially and fully edentulous patients has been considered as a reliable and safe treatment option [6,7]. The predictability of the treatment outcome is dependent on the bone volume and density of the prospective recipient site. This in turn often necessitates additional bone augmentation procedures [8,9]. Studies show a positive correlation to bone health through the rehabilitation with dental implants. The ability to transfer strain into the bone which is essential for physiological functioning and remodelling, helps to maintain bone health [10]. The treatment of patients with disturbed bone metabolism as seen in osteoporosis has been subject of intense investigation in the field of dental implantology. Improvements in implant surface characteristics, design, surgical techniques and imagining technology has led to the consensus that moderate osteoporosis can be rehabilitated with long term success and predictability [11,12]. We present the clinical case of a patient with Singleton– Merten syndrome who, despite presenting with multisystem disorders including osteoporosis, was successfully rehabilitated with dental Implants.
2.
Outline of the case
A 15-year-old male patient diagnosed with Singleton–Merten syndrome presented to the University Hospital in Muenster, Germany in August 1996. This patient hails from a family in
which two other members have also been diagnosed with Singleton–Merten syndrome. They are the only three patients identified with this syndrome in Germany to our knowledge.
2.1.
Local findings
Intraoral examination revealed an abnormal mixed dentition with multiple retained deciduous teeth and missing permanent teeth which resulted in as a severe non-occlusional bite. The panoramic radiograph showed evidence of multiple impacted teeth and incomplete root development in the remaining permanent teeth. In order to establish a correct jaw relation in the horizontal and vertical aspect, acrylic bite planes were made for the posterior teeth in both the jaws (Fig. 1a). The upper incisors were restored with metal ceramic crowns and the lower anterior teeth were restored with an acrylic resin bridge spanning from #33 to #43. (both canine abutments had incomplete root development.) After four years of function the bite plane had to be replaced due to severe abrasion on the occlusal surfaces. In May 2000, teeth #11 and #21 were extracted due to poor prognosis and restored with an interim acrylic partial denture during the post-operative healing period of three months. Thereafter titanium implants were placed in relation to teeth #11(Friadent GmbH, Mannheim, Germany Frialit 3.8 mm 11 mm), #21(Friadent GmbH, Mannheim, Germany Frialit 3.8 mm 11 mm). The upper jaw was rehabilitated with a definitive implant supported screw retained prosthesis incorporating implants from teeth #11-21. In 2004, further four implants were inserted in relation to teeth #13, #14, #23, (Straumann1, Basel, Switzerland, Standard implant-Regular neck 3.3mmx11) #24 (Straumann1, Basel, Switzerland, Regular Neck-Standard implant 3.8 mm 11 mm) mm) which was restored with a partial denture spanning from #14 to # 24. In 2007, a titanium implant was placed in relation to tooth # 44 (Straumann1, Basel, Switzerland, Standard implantRegular neck 4.8 mm 10 mm) which was positioned through a retained tooth germ that was electively not removed. Due to a poor prognosis of the remaining teeth, the presence of the multiple impacted teeth, evidence of abnormal bone turn over and considering the general medical condition of the patient, two years later (2009), the patient presented to the department of Oral and Maxillofacial Surgery, Katharinen hospital, Stuttgart for further treatment. Apart from the aforementioned clinical findings, the patient also developed multiple carious lesions and chronic generalized periodontitis. It was determined that all erupted teeth were non-restorable and required extractions. Titanium Implant based restoration which necessitated the extraction of the impacted teeth was planned.
2.2.
Medical history
On examination of the medical history, it was revealed that the cardiovascular system showed evidence of progressive calcification. The condition had gradually worsened over the years and necessitated the replacement of the aortic and mitral valve. The patient also suffers from glaucoma and eczema. Furthermore the patient’s fingers and toes were
journal of prosthodontic research 59 (2015) 199–204
201
Fig. 1 – (a–d) Panoramic radiograph showing different stages of treatment: (a) teeth with generalized resorption of roots and bite planes for occlusal correction (2000). (b) Post implant surgery in the mandible when additional implants were inserted (2007). (c) 1-year post operative follow up of implants showing minimal bone loss (2008). (d) Stable bone niveau 13 years after the first implant placement (2013).
Fig. 2 – All the teeth were severely ankylosed. (a–c) Showing shortened roots and (d) the extracted mandibular teeth and restorations.
visibly shorter. He had chronic microcytic anaemia and mild depression and also complained of frequent nose bleeds.
2.3.
Surgery
The details of the surgical procedure that was undertaken in the lower jaw is as follows: The surgery was undertaken in
general anaesthesia (Propofol 1% (Disorivax 3 mg/kg/h), Remifentanil (Ultiva 0.4 mg/kg/min), and Recuroniumbromid (Esmeron 0.5 mg/kg.), and all procedure of extraoral and intraoral sterility were ensured. Each time the patient underwent surgery he was shifted from using Phenprocoumone (Marcumar1) to Heparin as the latter has a shorter half life and reduced the risk of post surgical thrombosis. Surgical
202
journal of prosthodontic research 59 (2015) 199–204
Fig. 3 – Perioperative photograph of (a) left mandibular implants insertion after extraction (b) the defects were filled with autologous bone harvested during osteotomy with a bone filter. (c) Geistlich Bio-GideW membrane placed over the defect to enhance bone regeneration.
extraction of impacted teeth/severely ankylosed teeth #85, #46, #47, #34, #75, #36, #37, #38, #55, #14, #16, #17, #53, #27, #28 were done as a first step. Fig. 2 shows the radicular and coronal portions of teeth that were extracted along with the crown and bridge restorations that were removed during the total extraction procedure. Further extraction of #35, #45 and endosseous implant placement in teeth region # 45, #46, 47, #34, #35, #36 and bone augmentation in lower jaw was done. Tooth #35 was very brittle and extracted under a microscope. It was situated in close proximity to the inferior alveolar nerve and had to be removed by multiple tooth sectioning. The implant osteotomy sites were prepared using a surgical template. In region #34, #35, #45, #47 Straumann1, Basel, Switzerland, Standard implants – Regular neck (4.1 mm 10 mm) in region#46, #36 Straumann1, Basel, Switzerland, Standard implants-Wide neck (4.8 mm 10 mm) were inserted. The lateral dehiscence was covered by bone particles obtained from the osteotomy from the bone filter. Collagen (KOLLAGEN-resorb, RESORBA Wundversorgung GmbH & Co. KG, Nuernberg, Germany) inserted into the extraction socket at for hemostasis and enhancing bone regeneration. Fig. 3 shows the intra-operative situation in the left side of the mandible where the bone defects were filled with autologous bone and covered by a collagen membrane (Geistlich Bio-Gide1, Geistlich Pharma, Wolhusen, Switzerland) membrane. Surgical wound closure was achieved by Vicryl 4-0 V5 violet (Ethicon, Norderstedt, Germany). The patient remained stationary in the hospital ward until post operative day 5 and thereafter made regular follow up examinations periodically and received provisional prosthesis. On Fig. 1(b) the panoramic radiograph shows the post surgical situation. After three months a second surgical approach was undertaken to uncover the implant placed in relation to tooth #35 and all the rest of the implants healed transmucosally and were visible in
the oral cavity. This was performed under local anaesthesia with continuous monitoring of the vital parameters using a medical monitor. (Philips IntelliVue X2 Draeger Primus, Mannheim, Germany). On Fig. 1(c) the panoramic radiograph shows uneventful healing at 1-year post implant insertion.
2.4.
Prosthodontic treatment and follow up
It was decided to fabricate a maxillary bar supported implant retained denture and a mandibular telescopic overdenture as shown in Fig. 1(d). Fig. 4 shows the occlusal view of the present clinical situation (2013) and the prosthesis at a 13 year follow up since the insertion of the first implants. Fig. 5 shows the intercuspal position of the maxillary and mandibular prosthesis in the present clinical situation (2013). The follow up consisted of oral prophylaxis quarterly along with clinical and radiological assessment of implant osseointegration.
3.
Discussion
The pathophysiology of this multi-systemic condition has not been elucidated till now. It is thought to be an autosomal dominant condition. The abnormal increased calcification seen in the aorta and the ventricles are the major medical problems in patients with Singleton–Merten syndrome. The sequelae of the progressive calcification have been the cause of death in all patients reported until date [2]. Recent research proves that bone responds to both hormonal as well biomechanical regulations. These two mechanisms are often opposite to each other. It has been shown that even when there is a relative large demand for calcium, functional loading can compete and maintain bone mass [13,14]. Osteocytes have a higher sensitivity to mechanical stimulation than osteoblasts. Bone disuse even for a short
journal of prosthodontic research 59 (2015) 199–204
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Fig. 4 – Post surgical follow-up after 13 years showing (a) maxillary implant supported bar attachment (b) mandibular telescopic implant abutment. (c–d) Maxillary and mandibular prosthesis.
Fig. 5 – Frontal view of intercuspal position of upper and lower denture in position of the patient. Note the signs of wear from the prolonged use of the denture.
duration may rapidly induce a hypoxic state of stress in osteocytes, which when extended may lead to apoptosis. This hypoxia may be reversed by short term physiological loading, which suggests that mechanical loading at such magnitudes play a key role in osteocyte viability [15,16]. Previous studies suggest a normal bone turn over and bone formation within 87% for the mean age with normal mineralization in this patient [17–19]. Serum levels of receptor activator of
NF-kappaB and osteoprotegerin were normal [18,19]. We speculate that a decreased osteoblastic number and/function maybe responsible for the phenotype in Singleton–Merten syndrome. Feigenbaum et al. and Rutsch et al. reported a pattern of acute resorption of teeth in this patient which may have subsequently led to ankylosis. This necessitated extensive osteotomy procedures to extract the teeth. Previous studies described implant placement in contact with dental roots [12,20,21] was considered as a possible alternative approach to the standard invasive procedure that requires removal of every root fragment [22]. The implant corresponding to tooth #44 was thus positioned through the impacted and ankylosed tooth. The soft tissues and hard tissues healed uneventfully. The post operative follow up of the patient showed minimal periimplant bone loss according to the guidelines of Alberktsson and Zarb and signs of periimplantitis were absent. This case report is the first to our knowledge to report complete rehabilitation with dental implants in a case of Singleton–Merten Syndrome. Considering limited dexterity and fine motor skills of the patient, hygiene friendly prosthetic rehabilitation was chosen. Since the genetic cause of Singleton–Merten syndrome is not known, there is no specific medical test that can definitively assign the diagnosis. The diagnosis is usually based on the characteristic facial appearance of the affected individual, and on the medical and dental features. This is one of the reasons why it is important for health professionals to
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recognize the characteristics and consequently refer such patients for the necessary multidisciplinary treatments.
4.
Conclusion
This case report shows that Singleton–Merten syndrome patients can benefit from dental implant treatment and that they can successfully be rehabilitated to restore form, function and quality of life to the patient. Further prospective studies using implants in Singleton–Merten syndrome patients are necessary to confirm whether dental implants can be routinely used in such patients.
Conflict of interest The authors declare no conflict of interest related to this study.
references
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