Document Type : Original Article
Authors
1 Oral Medicine and Periodontology Department, Faculty of Oral and Dental Medicine, Misr University for science and technology
2 Oral Medicine and Periodontology Department, Faculty of Oral and Dental Medicine, Cairo University
3 Oral Medicine and Periodontology Department, Faculty of Oral and Dental Medicine, Ahram Canadian University
Abstract
Keywords
Main Subjects
Introduction
Periodontitis is one of the most common diseases affecting the periodontium. Its main cause is bacterial plaque, that can result in destruction of the gingival tissues and periodontal supporting apparatus (Wang et al., 2005). The difficulty of controlling plaque in furcations is responsible for the presence of extensive lesions in this area (Waerhaug, 1980). Different treatment modalities are used in management of furcation depending upon degree of furcation involvement including scaling and root planning, furca plasty, tunnel procedure, root resection, bicuspdization and regenerative approach as guided tissue regeneration and bone grafts (Kornman and Robertson, 2000).
Hydroxyapatites (HAs) is considered as a family of grafting materials that have a high level of biocompatibility. It has decreased osteoconductivity and poor degradation properties. To improve such shortcomings, nanocrystalline hydroxyapatite (nano-HA) paste containing 65% water and 35% of nanostructured apatite particles has been used for augmentation procedures in intrabony defects (Thorwarth et al., 2005).
Nano-HA has a stimulating effect on cultured PDL cells resulted in increased proliferation rate of these cells which is linked to the activation of epidermal growth factor receptor (Kasaj et al., 2008)
Heinz et al,. 2010 reported that nanocrystalline hydroxyapatite bone graft substitute in treatment of intrabony periodontal defects, showed more reduction in the probing pocket depth (PPD) in the study group compared with the control group.
Platelet-rich fibrin (PRF) was developed in France by Choukroun et al (2001) and considered as a second generation of platelet concentrates, it generally accelerates soft and hard tissue healing.
The preparation of platelet rich fibrin from a patient’s blood is a very simple process as it requires neither anticoagulants nor bovine thrombin. Blood is immediately centrifuged at 3,000 rpm for 10 min as claimed by (Huang FM et al,. 2010). The process must start immediately after drawing the blood to prevent the polymerization of fibrin in diffuse way which may result in a small poorly formed clot (Jyotsna et al. , 2013). Doing it quickly, large PRF clot (approximately 40-60% of the product) will be obtained in the middle of the test tube inbetween the lighter clear platelet poor plasma and condensed red blood corpuscles (Dohan Ehrenfest et al., 2009).
Material and Method
Study Design
Sample size was determined using sample size calculator* in relation to previous study with mean 64.95 and standard deviation 15.75(Tatiana et al., 2006). At study power of 80%; the required sample was 6 and increased in the present study to 8 in each group to avoid any attrition during follow-up.
Eight healthy, mature (about 10-12 months old) male Mongrel dogs, weighting about 12-15 kg each with intact maxillary and mandibular teeth were selected for the study. Female dogs were excluded to avoid any hormonal disturbance masking the effect of regeneration.
The animals were housed in separate cages, supplied with food and a bucket for water and allowed to live in optimal conditions at the animal house, Faculty of Medicine, Cairo University where all the study procedures were done.
Induction of Anesthesia
The anesthetic agent used for induction of anesthesia was a mixture of Xylazine-HCl; 1mg/kg body weight and ketamine HCl; 5mg/kg body weight, via a 23 gauge intravenous cannula through the cephalic vein and local infiltration anesthesia with vasoconstrictor 1/80,000 adrenaline to decrease bleeding. Anesthesia were maintained during surgery by venous drip of 500mg Thiopental-Sodium/500 ml Dextrose 5%.
Flap Technique
Two mandibular premolars of both sides in each dog were selected for the study, Before starting the surgical procedure, the surgical sites were rubbed by Betadine 10% then with Bard Parker blade no. 15 sulcular incision was made extending from the mesial of the first molars to distal of the canine.
* Kane SP. Sample size calculator. Clincalc:https://clincalc.com/stats/samplesize.aspx.
mucoperiosteal flap was elevated and using a small rose head bur, class II furcation defects, measured 5 mm apicocronal and 2 mm deep inter-radicular were created surgically on the buccal side of these premolars.
All periodontal ligament fibers on the roots were removed using periodontal curettes. Rubber base impression material was used to fill the defects and induce an inflammatory response and prevent spontaneous repair(fig1).
The flaps were carefully adapted, and closed with bioresorbable sutures. The rubber base material was left in place for 3 weeks. After that, it was removed with curettes under general anesthesia. Periodontal debridement was performed. Daily application of topical 0.2% chlorhexidine was maintained for one week.
Four weeks later,afterinduction of Anesthesia; mucoperiosteal flaps were raised to gain access to furcation areas, all granulation tissues were removed, and root surfaces were planed. A reference notch was done on root surfaces at the bone crest level with a small 0.5 rose head bur to facilitate histomorphometric analysis. Sterile saline was used to clean the surgical site.
Figure (1): The defects filled with a rubber base impression material to inhibit spontaneous healing
Preparation of platelet rich fibrin
PRF was prepared by collecting 10 ml of venous blood drawn from the arteria femoralis on the hind leg of each dog and were immediately centrifuged at 3000 rpm for 10 min prior the beginning of the surgery.
In each dog the four surgically created furcation defects (2 in each side) were treated as follow:
First (Group A) was treated with Nano hydroxyapatite alone (Fig, 2a)
Second (Group B) was treated with PRF alone (Fig, 2b)
Third (Group C) was treated with Nano hydroxyapatite and PRF (Fig, 2c)
Fourth (Group D) debridement only (controls). (Fig, 2d)
The flaps were repositioned and secured by 4-0 bioresorbable sutures. Afer finishing the surgical procedure, all dogs were injected with antibiotics and pain killer as a part of post-operative care. The animals were followed for 90 days healing period. During the first 28 days, all dogs fed on soft diet in order to protect the wound from any mechanical trauma. Topical application of 0.2% chlorhexidine solution were maintained to fight against plaque accumulation.
Figure (2): (a) showing defect treated with Nano hydroxyapatite alone (b) showing defect treated with PRF alone (c) defect treated with Nano hydroxyapatite and PRF (d) defect
treated with debridement only (controls)
Post-operative Evaluation and Sacrifice
Dogs were sacrificed by excess anesthesia and the mandibles were dissected and biopsies were collected for histopathological examination. The biopsy were preserved in jar containing formalin 10% and sent to the pathology lab. For histopathological examination.
I- Microscopic examination
The mandible was carefully dissected, immediately fixed in 10% formalin, after that decalcification was done using ethylenediaminetetraacetic acid (EDTA) for 4 weeks. Then, tissue blocks were processed and embedded in paraffin. Four μm sections were cut perpendicular to the long axis of the tooth and mounted on glass slides. The collagen and new bone formation were detected by Masson`s Trichrome stain (fig , 3) (fig , 4) (fig , 5) (fig , 6) .
Figure (3): A photomicrograph of group A experimental specimen showing a mixture of woven bone and the more regular concentric lamellar bone (masson trichrome)
Figure (4): A photomicrograph of group B showing woven bone with wide osteocytes forming thickened irregular trabeculae. Note the widespread osteoblastic rimming and the dense fibrous background.(masson trichrome)
Figure (5) : A photomicrograph of group C experimental specimen showing mature lamellar bone (RED) surrounding marrow cavities and less organized woven bone (BLUE). (masson trichrome)
Figure (6): A photomicrograph of group D control spaceman showing irregular woven bone spicules rimmed by osteoblasts as well as densely packed Collagen fibers (masson trichrome).
II- Measuring the newly formed bone
The area of newly deposited bone was estimated using Leica Quin 500 analyzer computer system, (Leica Microsystems, Swizerland). The cursor was used to define the areas of newly deposited bone trabeculae or collagen, that were marked by a binary color which was measured by the computer. The image analyzer was calibrated automatically to transform pixels produced into actual micrometer units.
The percentage of newly-formed bone was evaluated in five different fields in each group
with magnification (x100). Both mean values and standard deviation (SD) were calculated for all groups.
Results
Histomorphometric analysis:
I- Area percent of collagen
The greatest area percent of collagen was recorded in Group D, whereas the lowest mean value was recorded in group A. Analysis of variance (ANOVA) test revealed that the difference was statistically significant (p<0.0001). Tukey’s post hoc test revealed a significant difference between each two groups, except between groups B, C (Table 1) (Table 2).
Table (1): Detailed results of Tukey’s post hoc test for difference between groups regarding the area percent of collagen
Groups |
Significance |
Group A versus Group B |
0.0132* |
Group A versus Group C |
0.0008* |
Group A versus Group D |
<0.0001* |
Group B versus Group C |
0.0668ns |
Group B versus Group D |
<0.0001* |
Group C versus Group D |
0.0007* |
Table (2): Area percent of collagen in different groups and significance of the difference using ANOVA test
Group A |
Group B |
Group C |
Group D |
|
Mean |
17.566 |
28.702 |
40.359 |
64.774 |
Std Dev |
1.75 |
7.658 |
9.617 |
3.394 |
Max |
19.813 |
38.245 |
52.224 |
69.995 |
Min |
14.556 |
20.598 |
27.486 |
59.489 |
F value |
44.23 |
|||
P value |
<0.0001* |
II- Area percent of bone
The greatest area percent of bone was recorded in Group A, whereas the lowest mean value was recorded in group D. Analysis of variance (ANOVA) test revealed that the difference was statistically significant (p=0.047). Tukey’s post hoc test revealed a significant difference between groups A and D only (Table 3) (Table 4).
Table (3) Detailed results of Tukey’s post hoc test for difference between groups regarding the area percent of bone
Groups |
Significance |
Group A versus Group B |
0.1376ns |
Group A versus Group C |
0.4924ns |
Group A versus Group D |
0.0035* |
Group B versus Group C |
0.5108ns |
Group B versus Group D |
0.1894ns |
Group C versus Group D |
0.0631ns |
Table (4) Area percent of bone in different groups and significance of the difference using ANOVA test:
Group A |
Group B |
Group C |
Group D |
|
Mean |
36.442 |
29.08 |
32.811 |
23.147 |
Std Dev |
5.784 |
8.13 |
8.993 |
4.412 |
Max |
41.23 |
44.457 |
45.683 |
28.279 |
Min |
25.169 |
19.987 |
21.966 |
16.534 |
F value |
3.321 |
|||
P value |
0.047* |
Discussion
Animal studies are efficient complementary to in vitro studies prior to apply new clinical treatments because biopsy harvesting for histology is inapplicable in humans. Thus, animal experimentation is a necessary bridge prior to clinic application (Struillou et al, 2010; Seol et al, 2010). Many animals have been used in evaluation of periodontal regeneration however; dogs and nonhuman primates are considered the most devilishly used in literature (Bogle et al,. 1997). A chronic class II furcation defect was used to hinder spontaneous regeneration that may reduce the sensitivity of testing any regenerative power in acute defects (Soares et al, 2005).
To create such chronic defect a rubber base impression material was used to prevent spontaneous repair and induce an inflammatory response as reported by (Burcak Simsek et al ,. 2012). The critical-sized defect is the minimal size of a defect that can not heal spontaneously (Liu et al, 2010).A surgically created furcation defect is better than natural plaque-induced chronic defect, as the surgical preparation saves more time and permits standardization of the defect as reported by Jung et al, 2011. In the present study, the defect size measured five mm in the apicoocclusal direction and two mm deep in horizontal direction and was performed on the buccal side of the mandibular second and third premolars as this defect size was reported in many studies to work as class II furcation defects (Plínio Regazzini et al ., 2004 ; Suaid et al,. 2011 and Burcak Simsek et al ,. 2012 ). Histologic analysis was necessary in this study to evaluate the effectiveness of the regenerative techniques and to predict the presence and the extent of periodontal regeneration as done by Burcak Simsek et al., 2012.
The usage of PRF in regenerative periodontal procedures is based on the presence of many growth factors within a homogenous, 3-dimensional organization of fibrin meshwork which contains circulating cytokines (Dohan Ehrenfest et al ,. 2009). Growth factors release from the PRF membrane could further augment the regenerative power of the bone cells, leading to considerable amount of bone formation (Sambhav Jain et al,. 2014). The combined use of both PRF and Nano-HA could accelerate healing processes getting use of the synergic effect of the powerful inherent regenerative potential of PRF and the osteoconductive property of Nano-HA. In the present study, Nano-HA was used based one the hypothesis that the Nano structured materials have a huge number of molecules on their surface when compared to bulk materials. Although Nano-HA showed close contact with surrounding tissues and quick resorption characteristics, It was found that undisturbed osseous-integration and complete resorption occurred within 12 weeks (Schwarz et al., 2006).
The Nano-HA as bone graft substitute could result in rapid healing of critical sized defect in animal’s experiments and human trails. Schnettler et al., (2004) reported that Nano-HA stimulates bone healing by activation of osteoblast. Nano-hydroxyapatite has been used successfully to fill in bone defects. It provides an ideal scaffold for new bone formation in animal studies, this bone substitute with small granules that allow more bone substitution. It has been widely used in bone regeneration, implant tooth replacement, and intra-bony defects as reported by Lekovic et al., 2012.
The present study showed that, the largest area percent of newly regenerated bone was observed in the (PRF+ NHA bone) group, followed by the PRF group, then the NHA group, with the least value recorded in the control group. The difference was not statistically significant except in comparing (PRF+ NHA group) with control group (p<0.05). The maximum regenerative potential was noticed in combined PRF and NHA group than other groups. PRF has angiogenic properties that might lead to an increased probability of revascularization and enhances consolidation of the graft when used in combination with an osteoconductive medium. NHA application showed non-significant improvements compared with the control group. Non statistically significant improvement was observed in PRF group compared with bone group regarding % of newly formed bone in the defect, this was in accordance with Wang and Boyapati 2006 who reported that angiogenesis is a critical factor for success in furcation regeneration and as PRF play an important role in angiogenesis and contain growth factors such as PDGF and TGF β that cause better induction of osteoblastic differentiation as well, PRF clot provide a scaffold for recruitment of tissue cells to injured site (Dohan et al., 2006; Dohan et al., 2009 ). In the control group (group D) extensive fibrous and mesenchymal activity was found with densely packed granulation tissue that formed of fibroblasts, new collagen fibers, and blood vessels. The histomorphometric results within this group showed the least area percent of the bone and this was in agreement with many authors who had reported the difficulty of periodontal regeneration in furcation defects (Bowers et al ,. 2003 ; Verma et al ,. 2013). The present study revealed no inflammatory or foreign body reaction and no root resorption or ankylosis in all included four groups. Clinically, no allergic or toxic reaction recorded during the study period indicating biocompatibility of Nano hydroxyapatite and the safety of platelet rich fibrin.
Conclusions
The use of platelet rich fibrin in treatment of furcation class II defects could result in a new bone formation in the furcation area .
Combining PRF with Nano hydroxyapatite bone graft in treatment of furcation class II defects could significantly accelerate healing processes.
References:
Wang HL, Boyapati L: “PASS” principles for predictable bone regeneration. Implant Dent 2006;15:8-17