Authors INDIA. Kumaraswamy Layout. Bangalore ; Karnataka INDIA

Transcription

1 Authors Dr. Rayapati Dilip Kumar Professor Department of Oral and Maxillofacial Surgery Dayananda Sagar College of Dental Sciences Dayananda Sagar Institutions Shavige Malleshwara Hills Kumaraswamy Layout. Bangalore ; Karnataka INDIA 2. Dr.Honey Verma Post Graduate Student Department of Oral and Maxillofacial Surgery Dayananda Sagar College of Dental Sciences Dayananda Sagar Institutions Shavige Malleshwara Hills Kumaraswamy Layout. Bangalore ; Karnataka INDIA 3. Dr.Prashanth N T Associate Professor, Department of Oral and Maxillofacial Surgery Dayananda Sagar College of Dental Sciences Dayananda Sagar Institutions Shavige Malleshwara Hills Kumaraswamy Layout. Bangalore ; Karnataka INDIA 4. Dr.Shobha E S Professor, Department of Oral and Maxillofacial Surgery Dayananda Sagar College of Dental Sciences Dayananda Sagar Institutions Shavige Malleshwara Hills Kumaraswamy Layout. Bangalore ; Karnataka INDIA

2 QUALITATIVE AND QUANTITATIVE ANALYSIS OF BONE FORMATION IN THE PERI-IMPLANT DEFECTS GRAFTED WITH POLYCAPROLACTONE (PCL) ALLOPLAST ENRICHED WITH PLATELET RICH FIBRIN (PRF) - A CLINICAL AND RADIOLOGICAL STUDY.

3 INTRODUCTION Dental rehabilitation of partially or totally edentulous patients with dental implants has become a widely accepted mode of treatment with reliable long term results. Augmentation of edentulous jaws with bone grafts and implant supported prosthesis has been under clinical research studies for many years. The availability of inadequate quantity or quality of bone for the implant rehabilitation of edentulous jaws resulted in unsatisfactory prosthetic rehabilitation from a functional and esthetic point of view and result in failure of these implants. Over the years, many techniques have been introduced to gain bone volume and quality for placement of dental implants for prosthetic rehabilitation.the gold standard is still autogenous bone, but intensive research strives to simplify the augmentation procedures, constantly looking for alternative methods like use of alloplastic polymers. Bioresorbable polymers are widely used in medical applications today and their potential use in implantology has been expanding rapidly. Polycaprolactone (PCL) which belongs to the family of aliphatic polyesters has been widely used as a suture material and as a contraceptive implant with drug eluting properties for the last 30 years. Similarly Platelet rich fibrin (PRF) may be considered as a second generation platelet concentrate as the natural concentrate is produced without any anticoagulants or gelifying agents. The biologic activity of the fibrin molecule is enough in itself to account for the significant cicatricial capacity and the slow polymerization mode confers to the PRF membrane that particularly favors the physiologic architecture to support the healing process around implants, leading to good quantity and quality of bone formation in defects. Assessing the densities of the cortical and trabecular bone and selecting the quality of bone for implant placement is critical. With the introduction of computed tomography a new dimension was added in assessing the bone to ascertain whether it is suitable to receive implants. The use of Pre-operative and Post -operative computed tomographic scan aids was used to analyze the quantity and quality of bone present in pre implant phase and to compare the amount of bone gained when peri implant grafting has been done using Polycaprolactone and Platelet rich fibrin. Polycaprolactone in the mesh form customly designed to use in grafting is a relatively new phenomenon in implant surgery.this study describes the role of Platelet rich fibrin when used in peri-implant defects along with alloplast (poly caprolactone).the clinical and radiological evaluation done pre-op and post op using computed tomographic scans allows a comprehensive evaluation of type and amount of in periimplant defects. MATERIAL & METHODS This study was designed to assess the quality and quantity of bone formation in the defects grafted with PCL enriched with PRF clinically and radiologically.study was conducted on patients selected for implant supported prosthetic rehabilitation. Ten out patients with insufficient alveolar bone height in whom peri-implant defect was observed intra operatively were considered for the study after a thorough preoperative work up by clinical and radiological (CT scan) assessment. A custom made case sheet was designed for the study to record the case history.all patients were informed about the study and Informed consent was taken after the patients were explained about the need for placement of alloplastic bone grafts along with Platelet rich fibrin. Preoperative CT scans were made in all patients to assess the bone height and for selection of appropriate implants. Inter arch height and bucco lingual width of the edentulous was recorded on study models and surgical acrylic template was prepared. Prior to surgery, patients were examined for fitness by clinical examination and routine hematological investigations. Tapered design endosseous implants were used and allograft (SYNCRONIE MEDICAL INDIA) was shaped and trimmed from a 2 x 2 cm mesh to appropriate size and was enriched with platelet rich fibrin, to fit around the implant platform as a collar in the region. Clinical assessment of the patients were done on third day, seventh day and third month post operatively for pain, swelling, infection, wound break down / soft tissue dehiscence, implant exposure and implant mobility. CT scans were taken immediately post operatively and after three months to assess the implant healing and bone regeneration. Volume wise measurements were done using SIEMENS,SOMATOM definition AS with standard parameters (360 mas,120 kv) by taking into consideration 1mm AXIAL & PARAXIAL CUTS stable s and the volume wise recordings were done.

4 PREPARATION OF GRAFTS(Fig ) Alloplast used in the study was POLYCAPROLACTONE mesh (syncronie) measuring 2 x 2 cm. The graft was trimmed according to the platform size of the implant placed, using sterile ophthalmic scissors and suitable drill bit of appropriate size to fit as collar around the implant. PLATELET RICH FIBRIN PREPARATION(Fig ) Routine hematological investigations and informed consent were taken before withdrawal of blood for Platelet rich fibrin preparation. Tourniquet was placed on the hand from which blood was to be drawn. In all patients, Cephalic Vein in the ante cubital fossa was used for blood withdrawal.18-gauge needle was used for drawing blood,5 ml of blood was drawn from the patient and placed in test tubes with no anticoagulant. The collected blood was centrifuged at 2000 rpm for 10 min, and blood separated into three layers, red lower fraction containing red blood cells, upper straw coloured cellular plasma and the middle fraction containing the fibrin clot. The upper straw coloured layer was then removed and middle fraction was collected, separating the clot from underlying RBC,s.The total dimensions of collected Platelet rich fibrin was 4 to 5 mm to be placed in the peri-implant defect.. SURGICAL PROCEDURE OF IMPLANT PLACEMENT(Fig ) In all cases Implants were placed under local anesthesia (2 % Lignocaine hydrochloride with 1:2,00,000 adrenaline).crestal incision was given with No.15 blade followed by reflection of mucoperiosteal flap. Implant osteotomy was performed using standard drill bits in sequence. Maintaining the parallelism sterile implant was palced. After placement of cover screws, the were assessed and deficient s were grafted with PCL enriched with PRF. RADIOLOGICAL ASSESSMENT Ct scans were done preoperatively to assess the bone height and for selection of appropriate implants. CT scans were also done immediately post op to evaluate the measurements of peri-implant defect and three month post operatively and assessed for implant healing and bone regeneration. CT Scans for all the patients was taken from the same machine SIEMENS,SOMATOM definition AS with standard parameters (360 mas,120 kv).for quantitative analysis Volume wise measurements were assessed in preoperative, immediate postoperative and three months postoperative scans by using the VOLUME TOOL, SYNGO SOLARIS 7 software taking into consideration the stable land marks like the mesial Cemento Enamel Junctions on either side of the edentulous regions, inferior border of the mandible, apices of the adjacent teeth, lateral aspect of the piriform aperture and all the pre-operative and post-operative volume wise measurements were compared and recorded.(fig ) Qualitative analysis was done by measuring bone density of the in peri-implant defect in terms of hounsfield unit (HU), using SYNGO BONE DENSITY TOOL in immediate post op and 3months post op CT scans and were compared to assess quality of in the vicinity of implant.(fig ) POST OPERATIVE PROCEDURE Antibiotics (Cap. Amox 500mg t.i.d for five days) and anti-inflammatory drugs (Tab.Imol t.i.d for three days) were prescribed along with oral hygiene maintenance instructions. Patients were checked for any pain/ swelling/ infection/ wound break down / soft tissue dehiscence in the implant region on third and seventh post-operative days. Patients were recalled after seven days for suture removal. Permanent prosthesis was given after 3 months. RESULTS All patients were assessed clinically and radiologically. Radiological assessment was done using computed tomograms. They were done pre operatively to assess the bone height, quality of bone and for selection of appropriate length and diameter of the implants, Immediate post-operative CT scan was done to measure periimplant defect and three months post operatively, before the commencement of prosthetic phase scans were

5 assessed for implant healing and bone regeneration in the peri-implant defect. The immediate post op and the third-month postoperative CT scans were compared. The measurements of the defect was calculated in terms of volume in cm cube(cm3) in the computed tomograms using the VOLUME TOOL of the SYNGO SOLARIS 7 software, which gives accurate measurements volume wise. SYNGO SOLARIS software was used taking into consideration the stable land marks in the scans like the Cemento -Enamel Junction of the teeth on either side of the edentulous regions, inferior border of the mandible, coronoid and condylar process, lateral aspect of piriform aperture and apices of the teeth on either side of the edentulous regions. Quality of in the peri- implant after three months was assessed by the SYNGO BONE DENSITY TOOL, which measured bone density in the terms of hounsfield unit (HU). Comparison of values were done for the immediate post op and 3months post op CT scans which revealed the type of in the vicinity of the implant. Radiological evaluations using CT scans showed substantial increase in the volume wise bone measurements at the grafted regions (with PCL & PRF) at the end of three months, the around the implant was of good quality with high density values. The average volume of in peri-implant defect in single implant cases put together was approximately around 1.50 cm 3 in the grafted regions and in multiple implant cases, around 3.5 cm 3 when compared with the preoperative values. The quality of 3 months post operatively was superior with high HU values when compared with preoperative bone quality.the increased HU values on average ranged from 312 HU preoperatively and 457 HU 3 months post operatively. In one of the case, loss of graft was recorded 1 week post operatively and when the peri-implant was assessed three months post operatively the volume of was less with low HU values signifying poor quality of when compared with successfully grafted peri-implant s. Clinical evaluation on the third postoperative day showed pain and swelling in few cases. Implants were stable clinically in the immediate postoperative period and after three months. Clinical evaluation done after three months gave positive results and during the time of final prosthesis placement no complications related to the mechanical components of anchorage units were noted.. Soft tissue healing was excellent. Patient satisfaction related to aesthetics, comfort, function and recovery was good with eventual decrease in clinical symptoms like pain,swelling, & wound dehiscence considering the third post operative day to 3 months post operatively. In non of the patients findings like implant exposure and implant mobility was recorded. DISCUSSION Polycaprolactone is a scaffold with a fully interconnected 3D matrix architecture. These scaffolds were hypothesized to be suitable grafts for mandibular reconstruction because they: 1) eliminate the need for an autogenous donor site 2) are available in unlimited quantity and consistent quality 3) have a highly porous and honeycomb-like architecture that facilitates the infiltration of new osteoid and bone trabeculae 8,9 4) do not evoke an undesirable prolonged inflammatory response 9 and 5) can withstand local mechanical stresses 10. Platelet rich fibrin was first used by Choukroun et al. in France and belongs to a new generation of platelet concentrate 1. Simplified processing technique not requiring biochemical products for its preparation, makes it superior to PRP. PRF can be used to promote wound healing,bone growth, graft stabilization, wound healing and hemostasis because the fibrin matrix is better organized, which more efficiently direct stem cell migration and the healing program 2,3. The analysis of our results makes it possible to establish significant working parameters concerning biologic PRF features. After comparison of our values with those obtained for volume of peri-implant defect immediately post op and three months post op it is possible to consider that on the whole, PRF platelet cytokines remain trapped in the fibrin meshes, and probably even in the fibrin polymers which promotes bone formation in the and promotes implant stability. In vitro release of growth factors from PRF and the results of in vivo studies has now put forward a proposal to optimize the clinical application of PRF 4. Such studies have shown better results of PRF over PRP 5. The findings by Wiltfang et al. from a series of clinical trials

6 showed encouraging results. Dohan et al proved a slower release of growth factors from PRF than PRP and observed better healing properties with PRF. In a study by Bensaid et al 6 it was observed that the cells are able to migrate from the fibrin scaffold, while Kawamura and Urist demonstrated that PRF may act as a supportive matrix for bone morphogenetic protein as well 7, the same fact has been proved in our study through a good quality of bone which is formed in the vicinity of implant where PRF had proven to be a scaffold concentrating growth factors to allow osteogenic activity. In this study, the PCL scaffolds were tested in combination with PRF for the treatment of defects with respect to new bone formation, after 3 months of implantation. The quantitative and qualitative CT imaging analysis showed that the PRF-treated defects had higher bone volume fraction when assessed three months post operatively. The onset of new bone conduction can be attributed to the properties of the PCL scaffold itself. Scaffolds for peri implant defects provided at least a temporary load-sharing, if not load-bearing, to withstand the forces of mastication. The permeability to the scaffolds, both seeded it with bioactive substances and for cellular and vascular infiltration when implanted 11. Besides possessing the above characteristics, the architecture of the PCL scaffolds acted as a blotting medium to absorb any hematoma and subsequently promote blood clotting via the release of calcium ions on its surface, necessary for normal wound healing 12.The other reason for the augmented bone volume fraction measurement was the application of PRF which is an autologous plasma rich in growth factors that can serve as local regulators for bone regeneration and hence exert a beneficial effect on bone healing in critical-size defects 13. Combining PCL and PRF, a controlled release of growth factors is possible 14,15,16. In our study, implants has been placed successfully to regenerate new bone in a critical defect of adopting the strategy of a load-bearing 3D PCL scaffold with PRF. The harvesting of autogenous bone and its transplantation, so far the only safe alternative, was thereby avoided. Based on these results and the effects of combination of the 3D PCL with mesenchymal stem cells 17, it is clearly indicative of a real alternative to autogenous bone transplantation, especially for patients with absolute or relative contraindication for bone removal. This must be considered particularly with regard to the well known problems at the donor region and for the recipient patient as well. Springer et al. and Macacci et al. have published similar positive results as to the combination of scaffolds 18 and stem cells 19, respectively. Considering comparative bone density assessed pre and post operatively in our study, the bone generation capacity of both the grafts ( PCL & PRF ) can be explained. There are also important intra- and inter-individual differences in patients due to their individual clinical situation in relation to quality and quantity of. It could also be concluded that patient in whom defect was grafted with PRF & PCL had minimum or limited post operative events characterized as swelling, pain, infection etc. Our study group consisted of a limited number of patients with a limited follow up period. Hence a more extensive study on more number of patients with a longer period of follow up is required to come to a definitive conclusion. Regarding different scaffolds in combination with growth factors and for stem cells, further research will be necessary to define the results of bone healing. Further clinical studies are necessary to develop bone regeneration in vivo with different scaffolds in combination with growth factors and for stem cells CONCLUSION In the study conducted in the Department of Oral and Maxillofacial surgery, Dayananda Sagar College of Dental Sciences, we assessed the efficacy of alloplast polycaprolactone(pcl)when used along with platelet rich fibrin(prf) in the Peri implant deficient regions. The results obtained suggested that Polycaprolactone enhances early bone healing (3 months) when used along with platelet rich fibrin. Substantial increase in the volume wise measurement of bone (using VOLUME TOOL, SYNGO SOLARIS 7) post operatively by computed tomograms after three months was observed. Clinically no major complications were noted after 3months when assessed using parameters like implant mobility, pain, infection, implant exposure. Our findings support the use of Polycaprolactone as an alloplast along with platelet rich fibrin in deficient regions. It can be concluded that PCL can be used efficaciously clinically and radiographically in the treatment of a peri- implant defect. PCL is an efficient and readily available alloplast, found to be clinically effective and economical amongst available regenerative materials and is more fruitful when used along with PRF. However due to limited sample size in our study, considering future prospects a long term continuation, multicenter randomized, controlled clinical trial is in process to know its clinical and radiographic effect over bone regeneration.

7 ILLUSTRATIONS AND TABLES PREPARATION OF ALLOPLASTIC GRAFT MATERIAL (PCL) Fig 1.1 Alloplastic graft sheet, polycaprolactone(pcl) (2 X 2 cm) Fig 1.2 PCL trimmed to appropriate size to adapt in the defect

8 PREPARATION OF PLATELET RICH FIBRIN Fig 2.1 Platelet rich fibrin prepared as a layer between RBCs below & Platelet poor plasma above. Fig 2.2 PRF separated from underlying RBCs using sterile scissor Fig 2.3 PRF membrane obtained after draining excess of serum in a sterile lint free cloth

9 SURGICAL PROCEDURE Fig 3.1 Preoperative assessment of the edentulous Fig 3.2 Drilling done in sequence using burs along with External Irrigation Fig 3.3 Preparation of osteotomy site

10 Fig 3.4 Sterile Implant to be placed into the oral cavity Fig 3.5 Implant with Cover screws placed along with alloplast (PCL) enriched with PRF in deficient s.

11 QUANTITATIVE ANALYSIS OF BONE FORMED IN PERI IMPLANT DEFECT Fig 4.1 Volume of implant Fig 4.2 Volume of peri-implant defect (immediate post op) Fig 4.3Volume of peri-implant (3 months post op)

12 QUALITATIVE ANALYSIS OF BONE FORMED IN PERI IMPLANT DEFECT Fig 5.1 Bone density measured in using HU (pre op) Fig 5.2 Bone density measured in using HU (post op)

13 TABLES RADIOLOGICAL ASSESSMENT OF PERI IMPLANT DEFECT IN TERMS OF QUALITY AND QUANTITY OF BONE. TABLE 1(Quality of bone) Cases Implant site HU unit /pre-op HU unit/3 months post op Inference Case Quality of Case 2(loss of graft recorded) Quality of is inferior Case Quality of Case Quality of Case Quality of Case Quality of Case Quality of Case Quality of Case Quality of Case Quality of

14 TABLE 2(Quantity of bone) Cases Implant site Volume of bone/immediate post op (cm 3 )[V d] Volume of bone/3 months post op (cm 3 )[V b] Inference Case Bone of 0.15cm 3 in Case 2(loss of graft recorded) Peri implant defect still persist Case Bone of 0.11cm 3 in Case Bone of 0.31cm 3 in Case Bone of 0.36 cm 3 in Case Bone of 0.33 cm 3 in Case Bone of 0.51 cm 3 in Case Bone of 0.46 cm 3 in Case Bone of 0.31 cm 3 in Case Bone of 0.40 cm 3 in