|Year : 2016 | Volume
| Issue : 4 | Page : 187-192
Clinical and radiographic evaluation of the influence of antihyperglycemic drug (metformin) on healing of bone and periodontal defects after impacted mandibular third molar surgery
Shereen W Arafat PhD 1, Rania F Abdulmaguid2, Mohamed H Abou Ghaly3
1 Department of Oral and Maxillofacial Surgery, October University for Modern Science and Art (MSA), Cairo, Egypt
2 Department of Oral Medicine and Periodontology, Faculty of Dentistry, October University for Modern Science and Art (MSA), Cairo, Egypt
3 Assistant Professor Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Cairo, Egypt
|Date of Submission||05-Jun-2016|
|Date of Acceptance||08-Aug-2016|
|Date of Web Publication||14-Dec-2016|
Shereen W Arafat
36 B North Caneon Area, Dream Land, Cairo
Source of Support: None, Conflict of Interest: None
The purpose of the current study was to clinically and radiographically assess the regenerative potential of metformin in enhancement of bone healing in third molar extraction sites.
Patients and methods
The present study included 40 healthy volunteers (27 females and 13 males) aged 21-27 years who had been scheduled for surgical removal of their impacted mandibular third molars. Volunteers were randomly assigned to either groups A or B. Twenty patients of group A (test) underwent surgical removal of impacted mandibular third molar followed by application of metformin gel in the surgical site. Twenty patients of group B (control) underwent surgical removal of impacted mandibular third molar only. Clinical and radiographic evaluation (cone beam computed tomography) was performed immediately after operation and at 6 months postoperatively in terms of the probing pocket depth, the bone defect length at the distal side of second lower molars, and bone density. Data were collected and statistical analysis was performed.
At 6 months postoperatively group A (test) showed significantly higher (P ≤ 0.001) mean bone density compared with group B (control). On the other hand, there was nonsignificant (P ≥ 0.001) difference in the periodontal pocket depth and defect length between the test and control groups after 6 months.
There was a significant improvement regarding bone density at the surgical site using metformin after impacted mandibular third molar removal. Thus bone-formative effects of the common oral antihyperglycemic agent MF can provide a new direction in the field of bone healing.
Keywords: impacted third molar, metformin, periodontal defects
|How to cite this article:|
Arafat SW, Abdulmaguid RF, Abou Ghaly MH. Clinical and radiographic evaluation of the influence of antihyperglycemic drug (metformin) on healing of bone and periodontal defects after impacted mandibular third molar surgery. Tanta Dent J 2016;13:187-92
|How to cite this URL:|
Arafat SW, Abdulmaguid RF, Abou Ghaly MH. Clinical and radiographic evaluation of the influence of antihyperglycemic drug (metformin) on healing of bone and periodontal defects after impacted mandibular third molar surgery. Tanta Dent J [serial online] 2016 [cited 2017 Jun 27];13:187-92. Available from: http://www.tmj.eg.net/text.asp?2016/13/4/187/195709
| Introduction|| |
The removal of impacted third molars is a common oral surgical procedure. Problems arise if the impacted teeth are mal-inclined and in contact with adjacent teeth, this usually leads to damage to the adjacent dental and bony structures. The only available option here is surgical removal of the third molar followed by debridement and curettage in the area . Mesioangular impacted third molar is among the most damaging positions of impacted mandibular third molars because it results in osseous defects distal to the second molar and/or the development of periodontal defects around the latter [2-5]. Controversy exists regarding the need for a reconstructive procedure to eliminate persistent, or prevent the development of new, periodontal defects on the distal aspect of the second molar after third molar removal .
Many studies have evaluated the therapeutic effect of various reconstructive techniques, including bone substitutes such as demineralized bone matrix, synthetic bone matrix, platelet-rich plasma, guided tissue regeneration, and soft tissue procedures, after third molar removal [7-9].
Healing of bone is a complex process which involves participation of many cell types and growth factors. The healing of fracture or wound is accomplished by the interaction of osteoblasts and extracellular matrix under the influence of various growth factors . These factors can activate the proliferation and differentiation of the local osteoprogenitor cells into bone forming cells leading to the formation of new bone matrix and mineralization .
Metformin (MF) is one of the commonly used oral antihyperglycemic agents for treatment of type II diabetes mellitus, it is a second generation biguanide that decreases blood glucose levels by decreasing hepatic glucose production and decreasing peripheral insulin resistance .
Recent research has referred to the novel therapeutic action of MF in stimulating osteoblastic differentiation and bone formation. MF also promoted osteoblastic differentiation: it increased type 1 collagen production in both cell lines and stimulates alkaline phosphatase activity in MC3T3E1 osteoblasts (rat calvaria). In addition, MF markedly increased the formation of nodules of mineralization in 3 weeks MC3T3E1 cultures [13,14]. The MF treatment of rats induced a significant reduction in alveolar bone loss compared with vehicle-treated rats with regard to osteoblast differentiation. MF augmented the mineralization of MC3T3E1 cells approximately two-fold versus the nontreated cells. The possible bone-sparing and bone-formative effect of MF has been shown to significantly decrease intracellular reactive oxygen species and apoptosis and also have a direct osteogenic effect on osteoblasts, which could be partially mediated via promotion of Runx2 and insulin-like growth factor-1 expression .
Cortizo et al.  has demonstrated that MF causes a direct osteogenic action in a model of osteoblasts in culture. These actions include a dose-dependent increase in cell proliferation, type I collagen production, alkaline phosphatase activity, and mineral deposition. These osteogenic actions of MF appear to be mediated by an increase in the expression of nitric oxide synthases and in the activity of extracellular regulated kinases. Recently, Kanazawa et al.  have confirmed these results and suggested that MF can induce the differentiation and mineralization of osteoblasts via activation of AAMP activated protein kinase pathway and induction of endothelial nitric oxide synthase and bone morphogenetic protein-2 expression.
The main purpose of the present study was to clinically and radiographically assess the regenerative potential of MF to enhance bone healing in third molar extraction sites.
| Patients and methods|| |
A total of 40 healthy volunteers (27 females and 13 males) aged 21-27 years who had been scheduled for surgical removal of their impacted mandibular third molars at the Dental Clinics of October University of Modern Sciences and Art were selected. All patients were informed and signed a written consents for sharing in this research according to the Committee of Ethics of Faculty of Dentistry, October University of Modern Sciences and Art.
Each volunteer was assessed clinically and radiographically (preoperative panorama). The main criteria to select volunteers were absence of any kind of systemic involvement, not smokers, good oral health, with no gingival inflammation and the presence of mesioangular or horizontal impacted mandibular third molars, which were indicated for extraction. All selected patients were prepared by doing thorough oral prophylaxis. Patients were extensively informed about the procedures, including the uncertainties of using a new bone regenerative material. All patients signed an informed consent before their participation in the study. Volunteers were randomly assigned to either groups A or B. Twenty patients of group A (test group) underwent surgical removal of impacted mandibular third molar followed by application of MF gel in the surgical site. Twenty patients of group B (control group) underwent surgical removal of impacted mandibular third molar only. Surgical extractions were carried out by the same surgeon and the periodontal measurements were performed by the same periodontist.
Formulation of MF gel after intensive in-vitro investigations for optimization and stability, the MF gel was developed at the Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University. MF gel was prepared as described by Mohapatra et al. . Briefly, all the required ingredients of the formulation were weighed accurately. Dry gellan gum powder was dispersed in distilled water maintained at 95°C. The dispersion was stirred at 95°C for 20 min using a magnetic stirrer to facilitate hydration of gellan gum. The required amount of mannitol was added to the gellan gum solution with continuous stirring, and the temperature was maintained above 80°C. A weighed amount of MF was added with stirring. Then sucralose, citric acid, and preservatives (methylparaben, propylparaben) were added with stirring. Finally, the required amount of sodium citrate was dissolved in 10 ml distilled water and added to the mixture. The mixture was allowed to cool to room temperature to form gel.
All patients were given 0.12% chlorexidine as mouthwash for 1 min, and an extraoral antisepsis with 1% topical povidine. Regional blockade of inferior alveolar and lingual nerves was performed by using two cartridges (3.6 ml) of 2% mepivacaine/1: 100 000 epinephrine. A flap was an envelope incision with a releasing incision anterior to the second molar (three-cornered flap) performed according to Rosa et al. . The incision was performed along the post-molar triangle, starting well up on the ramus and keeping nearer the buccal side than the lingual. The horizontal incision was brought into contact with the distal surface of the second molar. The incision continued sulcularly to the mesiobuccal line-angle of the second molar with a releasing incision anterior to the second molar. After elevation of the designed flaps, bone removal and tooth sectioning were achieved using a low-speed surgical bur with copious irrigation. After curettage and careful irrigation, MF gel was applied in the sockets of group A patients, and group B patients left without graft [Figure 1]. The flap was repositioned, and closed with 3-0 braided silk interrupted sutures which were removed at seventh postoperative day. All patients received systemic antibiotic therapy (1 g/12 h augmentin; GlaxoSmithKline S.A.E, Cairo, Egypt), NSAIDs (400 mg, twice daily ibuprofen; Kahira Pharmaceuticals and Chemical Industries Company, Cairo, Egypt), and instructions on oral hygiene measures were examined 1 week postoperatively by the surgeon to ensure proper surgical healing.
Clinical and radiographic evaluation [cone beam computed tomography (CBCT)] was performed immediately after operation and at 6 months postoperatively.
The probing pocket depth (PPD) was measured just after surgery, and 6 months postoperatively at three sites, distobuccal, distolingual, and mid-distal around the second molar. The probing depth was measured using a 'Williams's graduated probe (0.5 mm of tip diameter; PQWBR; Hu-Friedy do Brasil, Rio de Janeiro, Brazil). It was inserted into the gingival sulcus parallel to the axis of the tooth until a slight resistance was observed. All measurements were made from the cementoenamel junction, and to the nearest millimeter.
Radiographic examination was performed by CBCT. The raw data obtained from the CBCT scanning were imported to the On Demand 3D software for secondary reconstruction (OnDemand3D, version 1.0.9; Cybermed, Seoul, South Korea). Two observers performed the image analysis in a blind and independent fashion. Each observer performed the analysis twice at two different sessions with a week interval in between the sessions. The interobserver and intraobserver agreement and reproducibility was more than 97% between each observer and himself and between the two observers as well.
To determine the bone defect length at the distal side of second lower molars, the distance from the cementoenamel junction to the alveolar bone crest was determined at distobuccal, mid-distal, and dentilingual of the lower second molar immediately after surgery and at 6 months postoperatively. For bone density, pixel intensity values were measured in squares of 30 × 30 pixels in eight different points at the distal of lower second molar, and the average of the 8 points was calculated. This was performed immediately after surgery and at 6 months postoperatively.
Data were collected and statistical analysis was performed with IBM SPSS (IBM Corporation, Armonk, New York, USA) statistics, version 23 for Windows.
| Results|| |
The age of the 40 patients included in the present study ranged from 21 to 27 years. Clinical evaluation of the postoperative healing revealed an excellent soft tissue response to both treatment modalities without any complications or adverse reactions. Preoperative angulation of the third molars of both groups (distribution according to Winter's classification) are listed in [Table 1].
|Table 1 Preoperative angulation of the third molars (according to Winter's classification) |
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The percentage change in PPD, defect length, bone density data showed nonparametric distribution; Mann-Whitney test used to compare between the two groups. Wilcoxon signed-rank test different used to compare between follow-up periods within each group for one density. The significance level was set at P value less than or equal to 0.001.
The mean and SD of the two groups for different clinical and radiographic tested parameters are listed in [Table 2].
|Table 2 Mean and SD of the two groups for different clinical and radiographic tested parameters |
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Periodontal pocket depth
There was nonsignificant difference (P ≥ 0.001) regarding the mean periodontal pocket depth among the two groups at immediate and 6 months postoperatively. There was significant decrease (P ≤ 0.001) on mean periodontal pocket depth for both groups at 6 months postoperatively [Figure 2].
|Figure 2: Line chart showing the mean PPD values in the two groups. PPD, periodontal pocket depth|
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There was nonsignificant difference (P ≥ 0.001) regarding mean defect length among the two groups at immediate and 6 months postoperatively. There was significant (P ≤ 0.001) decrease on mean defect length for both groups at 6 months postoperatively [Figure 3].
|Figure 3: Line chart showing the mean defect length values in the two groups|
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There was nonsignificant (P ≥ 0.001) difference regarding mean bone densities between the two groups at immediate postoperative evaluation. On the other hand; at 6 months postoperatively group A showed higher significant (P ≤ 0.001) mean bone density compared with group B.
There was significant increase (P ≤ 0.001) in mean bone density for the two groups at 6 months postoperatively [Figure 4].
|Figure 4: Line chart showing the mean bone density values in the two groups|
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| Discussion|| |
Controversy exists regarding the need for a reconstructive procedure after surgical removal of impacted lower third molar tooth. Many studies have evaluated the therapeutic effect of various reconstructive techniques. In contrast to a number of randomized clinical trials that have failed to show a clinically significant benefit from reconstructive procedures [7, 19, 20], some investigators have reported a significant improvement after lower third molar removal and grafting [6, 21, 22].
The present study investigated the effect of local application of MF on the periodontal tissue of the second molar and bone healing of the extraction site following surgical removal of mandibular mesioangular impacted third molar tooth. This effect was evaluated clinically and radiographically. The results of the present study have revealed that the PPD, defect length, and bone density has improved in all patients, irrespective of the test or control group.
Regarding the concentration of MF, Pradeep et al.  reported that local delivery of varying concentrations of MF gel into periodontal pockets stimulated a significant increase in the periodontal reduction, but both 1% MF and 1.5% MF showed maximum and similar improvement in clinical parameters. Thus hypothesized that 1% MF gel provides the optimum clinical benefit at the lowest concentration.
In the present study the use of 1% MF gel after surgical removal of the impacted lower third molar tooth improved the bone density over the control group, which is in accordance with the study by Rao et al.  who reported that the local delivery of 1% MF gel into the periodontal pocket in smokers stimulates a significant increase in periodontal reduction, and improved depth reduction in vertical bone defects, compared with placebo gel.
Previous experiments have been performed on biologic transport of MF in osteoblasts to verify the feasibility of local drug delivery in vitro and found that osteoblasts can uptake MF. Moreover, MF was found to significantly decrease intracellular reactive oxygen species and apoptosis and also had a direct osteogenic effect on osteoblasts that could be partially mediated via promotion of Runx 2 and insulin-like growth factor-1 expression [15,25].
Furthermore, Borges et al.  have recently shown that 80 weeks of MF treatment induces very modest increases in lumbar spine and total hip bone mineral density. Thus, these possible bone-sparing and bone-formative effects of MF may be of considerable interest to the periodontist in managing periodontitis-induced alveolar bone loss.
On the other hand, some reports indicated that MF has no osteogenic effect or inhibits osteoblast differentiation [27,28]. MF was also shown to inhibit osteoclast differentiation in vivo and in vitro by stimulating osteoprotegerin and inhibiting receptor activator of nuclear factor kβ ligand expressions [29,30]. Furthermore, few clinical studies in diabetic patients have assessed the effect of MF as a monotherapy on fracture risk, and they show overall poor evidence that it has major anabolic effects on bone [31-34].
The present study showed nonsignificant difference in the periodontal pocket depth and defect length between the test and control groups after 6 months. This could be attributed to the fact that the distal portion of the second molar (adjacent to the extraction) was not affected in all cases. Thus, MF could not have any additional effect on the healing process of that aspect of the tooth.
| Conclusion|| |
According to the results of the present study, there was significant improvement regarding bone density at the surgical site where MF was applied. On the other hand, there was no clear benefit of using MF regarding defect length, and periodontal pocket depth on the distal surface of second molar tooth. Thus bone-formative effects of the common oral antihyperglycemic agent MF can provide a new direction in the field of bone healing. However, long-term, multicenter, randomized, controlled clinical trials are required.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]