Ridge augmentation in an organ transplant patient

Abstract

With the continuing progress in medicine, the number of successful organ transplantations has continued to increase, a fact that also concerns dentists and implantologists. Implantology after organ transplantation remains controversial due to the patient’s immunocompromised situation and the corresponding risk of infection. Only a few studies on this topic have been reported, with all of them showing the dental implant success rates in transplant patients to be similar to those in healthy subjects. However, immunosuppression has been identified as a contraindication to bone augmentation. Consequently, there is still a lack of knowledge regarding pre-implantology bone grafting procedures. The following case report describes the use of ridge augmentation and extended bilateral sinus lift procedures in a liver transplant patient. The patient was treated with an implant-supported fixed prosthesis in the upper jaw and was followed up for a total of 28 months after implant insertion. According to the findings presented, pre-implantology augmentation procedures may be performed successfully in immunosuppressed organ transplant patients. Stable peri-implant conditions were shown over a period of more than 2 years. Nevertheless, further investigations are needed to define a safe treatment protocol for these high-risk patients.

Liver transplantation has become the standard treatment for terminal liver disease, with more than 5000 transplanted patients annually in Europe. Due to advances in medical and surgical knowledge, solid organ transplantation has in general become a predictable therapeutic modality. Nevertheless, every transplantation is associated with a certain degree of immunosuppression, which is often severe. As the number of transplant patients has continued to increase, the treatment of such patients has gained attention in the fields of dentistry and implantology. However, dental implant therapy in these transplant patients is controversial because of their altered wound healing and the risk of infection due to their immunocompromised condition. On the other hand, there are a few reports in the literature describing successful implant treatment after solid organ transplantations. Despite the encouraging data, there is still a lack of knowledge regarding pre-implant ridge augmentation procedures in organ transplant patients.

The present report describes the dental rehabilitation of a liver transplant patient, which included maxillary ridge augmentation and sinus lift followed by the insertion of six dental implants. The patient was followed up for 24 months after the final prosthetic rehabilitation.

Case report

In October 2011, a 60-year-old male patient was referred to the University Clinic of Craniomaxillofacial Surgery of Innsbruck because of recurrent complaints related to his upper denture. The first clinical investigation revealed multiple pressure sores along the maxillary vestibule, combined with an insufficient upper denture.

The patient’s medical history included a first liver transplantation in June 2008 due to hepatocellular carcinoma (HCC) in the context of chronic hepatitis C. Unfortunately the transplant failed 3 years later because of a relapse of the HCC in the transplanted liver. A second, successful transplantation was performed in November 2010, achieving stable organ function and acceptable laboratory parameters. Due to multiple recurrent dental abscesses after the first transplantation, all of the patient’s teeth were removed in October and November 2008 because of the risk of further infection under the immunosuppression conditions required. Removable dentures were made, but the patient complained of difficulties in feeding, chewing, and speaking from the first weeks onwards because of recurrent pressure sores and mobility of the upper denture. He did not, however, experience any difficulties with his mandibular prosthesis. Multiple denture relining procedures, which were performed in the following years, did not improve the situation. Furthermore, due to the nutritional disturbances, the patient experienced a body weight loss of 15 kg from 67 kg with a body mass index (BMI) of 21.9 kg/m 2 in 2009, to 52 kg and a BMI of 17 kg/m 2 in 2012.

As well as the hepatic disease, the patient also suffered from insulin-dependent type 2 diabetes mellitus and an iron-deficiency anaemia, both of which presented stable laboratory values under their respective therapies.

At the time of referral in 2011, the patient’s medical immunosuppressive therapy consisted of tacrolimus (Prograf, 3× 1 mg) and mycophenolate mofetil (MMF; CellCept, 2× 500 mg). Laboratory tests confirmed stable organ function ( Table 1 ).

Table 1
Laboratory values at first admission.
Parameter Value (reference range)
Alanine aminotransferase (ALT) 43 U/l (10–50)
Aspartate aminotransferase (AST) 43 U/l (10–50)
Total bilirubin 0.40 mg/dl (0.00–1.28)
Alkaline phosphatase (ALP) 107 U/l (40–130)
Gamma-glutamyltransferase (GGT) 46 U/l (10–71)
Albumin 3430 mg/dl (3500–5200)
Creatinine 0.97 mg/dl (0.67–1.17)
White blood cells (WBC) 4.2 × 10 9 /l (4.0–10.0)
Red blood cells (RBC) 4.99 × 10 12 /l (4.4–5.9)
Haemoglobin (Hb) 125 g/l (130–177)
Platelets (Plt) 167 × 10 9 /l (150–380)
HbA1c 7.2% (4.0–6.0)
Concentration of tacrolimus 5.9 ng/ml

Clinical and radiological (panoramic X-ray, cone beam computed tomography (CBCT)) investigations were performed in order to evaluate the amount of maxillary bone available for the placement of dental implants ( Fig. 1 ). These initial examinations revealed a severe horizontal and vertical bone deficit making implant placement impossible. Consequently, the stipulated treatment plan included a maxillary ridge augmentation prior to the implant procedure, with an implant-supported fixed prosthesis as the final goal. In November 2011, after obtaining detailed information on the patient and his informed consent, a bilateral sinus lift procedure combined with a maxillary lateral ridge augmentation was performed under general anaesthesia, using an autogenous iliac crest block graft and a particulate xenogeneic bone substitute material (Geistlich Bio-Oss). The bone blocks were fixed with osteosynthesis screws at the lateral aspect of the maxillary ridge from the left to the right premolar region. The sinus lift procedures were performed through a lateral access, which was covered with a collagen membrane after the insertion of the particulate augmentation material. Great care was taken during wound closure in order to avoid possible dehiscence due to excessive tension on the mucosa. The surgical procedure was performed under perioperative antibiotic prophylaxis with 2.2 g amoxicillin–clavulanic acid twice daily, starting 1 day prior to the intervention and continuing for 7 days in total. The patient was instructed to rinse with chlorhexidine 0.2% twice daily and not to wear his upper denture until removal of the stitches, which was done on day 10 postoperative. No dehiscence or wound healing disorder was noted.

Jan 16, 2018 | Posted by in Oral and Maxillofacial Surgery | Comments Off on Ridge augmentation in an organ transplant patient
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