Authors 1. Dr. Rayapati Dilip Kumar - Syncronei Medicalsyncronei.com/publication/pub6.pdf · 1. Dr....

Authors

1. 1. 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 560 078; Karnataka

INDIA

2. Dr.Honey Verma

Post Graduate Student

Department of Oral and Maxillofacial Surgery





INDIA

Email: [email protected]

3. Dr.Prashanth N T

Associate Professor, Department of Oral and Maxillofacial Surgery





INDIA

4. Dr.Shobha E S

Professor, Department of Oral and Maxillofacial Surgery





INDIA

mailto:[email protected]

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.

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 peri implant 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 peri implant 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 bone formed in peri-

implant defects.

MATERIAL & METHODS

This study was designed to assess the quality and quantity of bone formation in the peri implant 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

area 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 peri implant 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 areas and the volume wise recordings were done.

PREPARATION OF GRAFTS(Fig 1.1-1.2)

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 2.1-2.3)

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 3.1-3.5)

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 peri implant area were assessed and deficient areas 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 4.1-4.3)

Qualitative analysis was done by measuring bone density of the bone formed in peri-implant defect area 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 bone formed in the vicinity of implant.(Fig 5.1-5.2)

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 peri-

implant defect area and three months post operatively, before the commencement of prosthetic phase scans were

assessed for implant healing and bone regeneration in the peri-implant defect area. 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 bone formed in the peri- implant

area 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 bone formed 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 bone formed around the implant was of good quality with high density values . The

average volume of bone formed 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 pre-

operative values. The quality of bone formed 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 area was assessed three months post operatively the volume of bone formed was less with low

HU values signifying poor quality of bone formed when compared with successfully grafted peri-implant areas.

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 response9 and

5) can withstand local mechanical stresses10

.

Platelet rich fibrin was first used by Choukroun et al. in France and belongs to a new generation of platelet

concentrate1 . 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 program2,3

. 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 peri implant area 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 PRF4. Such

studies have shown better results of PRF over PRP5. The findings by Wiltfang et al. from a series of clinical trials

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 al6 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 well7, 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 peri implant 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 implanted11

. 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 healing12

.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

defects13

.

Combining PCL and PRF, a controlled release of growth factors is possible14,15,16

. In our study,

implants has been placed successfully to regenerate new bone in a critical defect of peri implant area 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 cells17

, 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 scaffolds18

and

stem cells19

, 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

bone formed. It could also be concluded that patient in whom peri implant 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 peri implant 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.

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 peri implant defect

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

SURGICAL PROCEDURE

Fig 3.1 Preoperative assessment of the edentulous area

Fig 3.2 Drilling done in sequence using burs along with External Irrigation

Fig 3.3 Preparation of osteotomy site

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 peri implant deficient

areas.

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 bone formed peri-implant area (3 months post op)

QUALITATIVE ANALYSIS OF BONE FORMED IN PERI IMPLANT DEFECT

Fig 5.1 Bone density measured in peri implant area using HU (pre op)

Fig 5.2 Bone density measured in peri implant area using HU (post op)

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

Case1 16 434 498 Quality of

bone formed

is superior comparatively

Case

2(loss of graft

recorded)

36 520 426 Quality of

bone formed is inferior

comparatively

Case 3 46 120 274 Quality of

bone formed is superior

comparatively

Case 4 35 107 302 Quality of bone formed

is superior

comparatively


is superior

comparatively


bone formed

is superior

comparatively



comparatively



comparatively


is superior

comparatively


is superior

comparatively

TABLE 2(Quantity of bone)

Cases Implant

site

Volume of

bone/immediate

post op (cm3)[Vd]

Volume of

bone/3

months

post op

(cm3)[Vb]

Inference

Case1 16 0.57 0.72 Bone enhancement

of 0.15cm3 in

peri implant area

Case

2(loss of

graft

recorded)

36 1.30 1.20 Peri implant

defect still

persist

Case 3 46 1.09 1.20 Bone

enhancement

of 0.11cm3 in peri implant

area

Case 4 35 0.58 0.89 Bone

enhancement of 0.31cm3 in

peri implant

area

Case 5 43 1.65 2.01 Bone

enhancement

of 0.36 cm3 in

peri implant

area

Case 6 26 1.45 1.78 Bone

enhancement of 0.33 cm3 in

peri implant

area

Case 7 47 1.03 1.54 Bone

enhancement

of 0.51 cm3 in peri implant

area

Case 8 42 1.23 1.69 Bone enhancement

of 0.46 cm3 in

peri implant

area

Case 9 31 1.58 1.89 Bone

enhancement

of 0.31 cm3 in peri implant

area

Case 10 25 1.32 1.72 Bone enhancement

of 0.40 cm3 in

peri implant area

Authors 1. Dr. Rayapati Dilip Kumar - Syncronei Medicalsyncronei.com/publication/pub6.pdf · 1. Dr....

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