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Authors: Dr. Vikram Ahuja, Dr. Shivangi Gupta, Dr. Abhishek Kr. Pandey

Abstract

Patients with prosthetic heart valves are maintained on lifelong oral anticoagulant therapy. The optimal anticoagulant management of such patients during surgical dental procedures has been debated for a long time. Valvular heart disease does not directly affect dental implant outcome; however, there is a major need for preventing potential infective endocarditis. As the cardiac tissue can be damaged in these patients, especially valves, the risk of bacteria-induced infective endocarditis can be high. Preoperative rinses with chlorhexidine can be beneficial together with antibiotic prophylaxis. If any infection persists around dental implants in these patients, necessary steps need to be taken very quickly, such as removing the implants (the infection) under stringent conditions. Patients with valvular prosthesis placement must be vigilant with their oral hygiene to prevent infection. Adult patients on oral anticoagulant therapy, like their healthy counter parts, may have a missing tooth or teeth as a normal because of periodontal problem and/or decay. Warfarin, a competitive inhibitor of vitamin K, is a commonly prescribed oral anticoagulant shown to reduce the risk of thromboembolism in patients with mechanical heart valves, deep vein thrombosis, and other hypercoagulable states. Its principle adverse effect is bleeding. The international normalized ratio (INR) is used to monitor therapy so as to make it safe and effective. The target INR varies (2.0–4.5) depending on the reason for anticoagulation. Osseointegrated implants have been shown to exhibit reliable results in the rehabilitation of fully and partially edentulous patients. Many dental implant systems have shown multiyear success rates,90% for fully edentulous patients. Similarly, multiyear studies of dental implants in partially edentulous patients have generally reported success rates around 90%for maxillary and mandibular prostheses.

KEYWORDS: DENTAL IMPLANT, PROSTHETIC VALVE, INFECTIVE ENDOCARDITIS PROPHYLAXIS,`RIDGE SPLIT TECHNIQUE,

INTRODUCTION

The availability of adequate bone volume for dental implant placement in aesthetic zone is often diminished by tooth loss. Loss of bucco-palatal dimension of ridge necessitates calls for additional procedure to receive optimum implant borne prosthesis. Ridge splitting with bone expansion is a technique of manipulation of bone to form receptor site for implant without removing any bone from the implant site. Maxillary bone has inherent quality of flexibility which can be moulded to desire location by using series of instrument namely chisels and osteotome. It is well-established that the implant placement must be prosthetically driven and not bone. If one fails to achieve necessary modification in bony defect prior to implant placement then aesthetic and may be functional failure is inevitable. When the bucco-lingual bone width is 3 mm or greater but <6 mm, to allow implant placement, augmentation of the alveolar ridge using a ridge splitting and bone expansion technique is a viable option. The 3 mm of bone should have at least 1 mm of trabecular bone sandwiched between the cortical plates. That will ensure 1.5 mm of bone (cortical and cancellous) on either side of the split ridge and allow the bone to spread and maintain a good blood supply. Several ridge split techniques have been developed in past few decades and includes split crest osteotomy, Ridge expansion osteotomy, and numerous modification of it.

 
 
CASE REPORT

A 50 year old female patient was reported in the dental opd of SIPS Hospital with chief complaint of missing upper anterior teeth. She wanted replacement of her missing teeth with the dental implants. We observed her during examination she seemed quite exhausted and had shortness of breath, but on questioning she gave no relevant medical history. So before we could proceed to implant surgery she was advised to get her ECG and other laboratory investigation done.

Investigation reveals

Severe calcific aortic stenosis, bicuspid aortic valve, max PG=167 MG=97mmHg

Aortic annulus=18mm Marked LVH, LVEF~65%, mild PAH, PASP~44mmHg

No RWMA seen, mild TR.

Then she referred to the cardiologist in SIPS hospital, and her valve replacement surgery done.

After six months patient returned to the dental opd of SIPS Hospital with the same chief complaint of missing upper anterior teeth. Consultation by her cardiologist was sought and after their clearance the implant surgery was planned. Patient was examined again; her right maxillary lateral incisor was grade III mobile. OPG and CBCT was advised and it revealed loss of bucco-palatal dimension of ridge. Ridge split technique would be applied in that region along with immediate implant loading was planned for the right maxillary lateral incisor after the extraction. The patient was willing for surgery under general anaesthesia as she did not want to bear any type of discomfort and pain. So her preanaesthesia clearance was sought under the Anaesthetist in the SIPS hospital. After ensuring that the patient clearly understood the procedure and possible complications a written consent form was taken.

A blood test was done 1 week before her planned surgical treatment and on the day of the procedure. The results showed an INR of 1.0 on the day of procedure. Upon consulting with her treating cardiologist it was decided that the procedure would be performed after discontinuing her warfarin for 3 days prior to surgery and aspirin for 5 days prior to surgery and patient was advised to take Vitamin k injection for 3 days prior to surgery. Amoxicillin 500mg tds for 5 days was prescribed to the patient as prophylactic antibiotic.

Her mouth was rinsed for 30 seconds with .2% chlorhexidine mouthwash Nasal intubation was done and throat pack was placed and anaesthesia with sevoflurane, N2O, O2 and recuronium was given. Blood pressure was maintained at lower side to reduce bleeding.

A crestal incision was given in the maxillary anterior region and combined muco-periosteal and mucosal flap was reflected on labial aspect and only mucoperiosteal flap on palatal side. The combined flap provides advantage of proper flap closure after ridge expansion. The exact location of implant on the ridge was marked by an indentation created by surgical blade. Three types of ridge expanding instruments namely, uni-beveled chisel, bibevelled osteotome and tapered osteotomes were used in the surgery. All these instruments were used by gentle tapping with mallet. Using uni-beveled chisel (2 mm), with bevel facing labial side, an indentation made on crestal cortex was perforated to reach cancellous bone. The bi-bevelled osteotome 2.5 mm, 3.5 mm in length and tapered osteotome 2 mm, 3 mm diameter at the tip were used alternately to expand the osteotomy

All the instruments after tapping to desired depth were wiggled back and forth in a mesio-distal direction with slight buccal pressure. This allows expansion of ridge facially with advancing osteotomies as well as easy removal of instrument without any risk of fracturing the labial plate.

Any crestal resistance if felt before reaching desired depth was relieved by advancing chisel cut mesial and distal to osteotomy. It was done using unibeveled chisel. This chisel cut extension allowed better relieving of stress concentrated at the crest during ridge expansion with osteotome. Similarly, any apical resistance if felt was relieved by the smallest diameter pilot drill by untouching the crestal bone. The final instruments closely matched the shape of the implant..2 XIVE (DENTSPLY) 3 mm × 11 mm implant was carefully placed in the maxillary anterior region and a healing abutment was placed. The space between the implants was filled with hydroxyapatite with collagen granules and Bio-Oss graft which is a Xenograft (xenografts are bone grafts from a species other than human.)

Next the maxillary right lateral incisor was extracted. The apical portion of the socket was carefully prepared using a conventional drill set for the implants to be used. A XIVE (DENTSPLY) 3mm: 11mm implant was placed in the socket and a healing abutment was placed, the space between the implant was filled with the same graft material. Periosteal releasing incision was performed to extend the flap coronally over the implant so as to achieve tension free interrupted sutures for a close approximation. Sutures were given and sterile gauze was placed.

The patient was given postoperative instructions and kept under observation 30 minutes after the operation. Intraoral examination 30 minutes after the procedure showed no bleeding in the surgical site. The gauze was exchanged, and the patient was discharged to be seen in 1 week. An antibiotic was prescribed (amoxicillin 500 mg, 3times/day) for the next 10 days, and analgesics (ibuprofen 400 mg) were to be taken only as required. Patient was advised to start her warfarin and aspirin from the next of the surgery as consulted by her cardiologist. Post operative examination was performed at the end of the week, and the patient showed good healing and no signs of 60%

 
 
 
 
 
 
 

Surgical placement of dental implants is a well-documented treatment for edentulism. Placing dental implants with right approach and with proper precautions would definitely increase the success rates. For the dental treatment of patients with prosthetic valve and on oral anticoagulant therapy it is important to evaluate the surgical risk and the possibility of thromboembolism and, it is important to take a careful history and perform thorough evaluation of INR. In 2008 Garcia et al. published an important prospective study on the risk of thromboembolism after a brief suspension of the OAT, reporting an incidence of thromboembolic events of 0.5%, in a follow-up period of 30 days. In the same study is also emphasized as the majority of postoperative bleeding begins after 2–3 days of surgery, by the action of plasminogen activators, resulting in clot lysis (crankcase). The surgery and anaesthesia should be performed in the least traumatic way; otherwise it would cause massive bruising. With regard to the guidelines in oral surgery in patients with OAT, the review by the American College of Chest Physicians recommends for co-administration of a pro-haemostatic local agent.

The reduction in the perioperative period of warfarin dosing or discontinuation of anticoagulant treatment 2 or 3 days before oral surgery procedure is a strategy widely used. Administration of vitamin k which reverses the action of anticoagulants and prevents bleeding. It aims to decrease the value of

INR with the prediction that in the next 48–72 hours will be in the range 1.5–2.1. The complete suspension of the OAT is often recommended to reduce the risk of post-operative bleeding, resulting in 4 days the return to a state of coagulation of a typical normal subject. This strategy may, however, expose the patient to increased risk of thromboembolic events. The need to prevent an attack of thromboembolism, in patients, classified as high risk of thromboembolism, should dictate the use of a Bridging Therapy protocol for the perioperative management, regardless of the risk of bleeding, especially in cases of minor oral surgery.

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