Topical administration of simvastatin recovers alveolar bone loss in rats

Therapeutic Effects of Statins: Promising Drug for Topical and Transdermal Administration

Statins are HMG-CoA reductase inhibitors and decrease plasma low-density lipoprotein cholesterol (LDL-C) levels. They are well tolerated, and because of their LDL-C-lowering effect, they are utilized to decrease the risk of atherosclerosis and cardiovascular disease. However, statins have pleiotropic effects, including immunomodulatory, anti-inflammatory, antioxidant, and anticancer. Currently, oral administration is the only Food and Drug Administration (FDA)-approved route of administration for statins. However, other administration routes have demonstrated promising results in different pre-clinical and clinical studies. For instance, statins also seem beneficial in dermatitis, psoriasis, vitiligo, hirsutism, uremic pruritus, and graft-versus-host disease. Topically applied statins have been studied to treat seborrhea, acne, rhinophyma, and rosacea. They also have beneficial effects in contact dermatitis and wound healing in animal studies, (HIV) infection, osseointegration, porokeratosis, and some ophthalmologic diseases. Topical and transdermal application of statins is a non-invasive drug administration method that has shown significant results in bypassing the first-pass metabolism in the liver, thereby reducing possible adverse effects. This study reviews the multifaceted molecular and cellular impacts of statins, their topical and transdermal application, novel delivery systems, such as nanosystems for topical and transdermal administration and the challenges concerning this approach.

Exploring the Synergistic Effect of Simvastatin in Oral Health Applications: A Literature Review

Statins are the first line of treatment for hyperlipidaemia. Along with lowering lipids, it also lowers mortality and cardiovascular risk. Statins play a major role in maintaining the homeostasis of the oral cavity via a number of different mechanisms. It includes regeneration of dentin and pulp by differentiation and increased development of mineralized tissue via the bone morphogenetic proteins (BMP)-2 Pathway. It shows effective bone health by leading to osteogenic differentiation mesenchymal stem cells, by facilitating epithelization process in wound healing, anti-inflammatory, antioxidant, antimicrobial, antiviral, and fungicidal properties. To the finest of the information we have, there have been very few comprehensive studies that have investigated the effects of statin drugs on various aspects of dental and oral health. As a result, the main objective of this review was to examine the effect of statins on oral health applications. According to the findings of our extensive review, statins have noteworthy and promising effects on several aspects of oral health, including dental pulp cells, chronic periodontitis, alveolar bone loss, orthodontic tooth movement, and so on. Nevertheless, it is concluded that local or even systemic administration of simvastatin should be regarded as an innovative, easily accessible, and safe therapeutic agent that has a significant impact on enhancing the oral health.

Longitudinal follow-up study of the association between statin use and chronic periodontitis using national health screening cohort of Korean population

Since a potential link between statins and the risk of adverse chronic periodontitis (CP) has been raised, we aimed to validate the association between statin use and the incidence of CP using nationwide cohort data. This longitudinal follow-up study included 169,381 patients prescribed statins who were matched with an equal number of controls using propensity scores from the Korean National Health Insurance Service-Health Screening Cohort database (2002–2015). A Cox proportional hazard model was used to assess the occurrence of CP following statin use after adjusting for multiple covariates. The occurrence of CP was significantly higher in patients who had long-term use (1–3 years, 3–5 years, or > 5 years) than with short-term use (≤ 1 year) of statins. After adjustment, statin users exhibited an occurrence of CP 1.32-fold higher (95% confidence interval 1.30–1.33) than that of the matched nonusers (incidence: 25.0 and 22.0 per 100 person-years, respectively). Subgroup analyses supported the adverse impact of statins on CP independent of age and gender. Statin user odds ratios for developing CP were higher compared to those of nonusers. This was consistent in individuals aged > 40 years in both genders, especially with long-term use.

Repairing Rabbit Radius Bone Defects with Simvastatin Compound Biological Bone

Objective: This study aimed to investigate the feasibility of repairing rabbit radius bone defects with simvastatin compound biological bone. Methods: Simvastatin biological bone material was prepared, and osteoblasts were cultured. A total of 42 New Zealand white rabbits were randomly divided into four groups, and a bone defect with a length of 15 mm was created at the middle part of the radial shaft of both limbs in each rabbit, thereby establishing a bone defect model. The grafts in group A were biological bones of osteoblasts combined with simvastatin; the grafts in group B were biological bones of simvastatin; the grafts in group C were biological compound bones of osteoblasts; and the grafts in group D were simple biological bones. In each group, four animals were randomly sacrificed at the sixth and twelfth week after surgery, and specimens were collected for gross observation, X-ray examination, histological observation, and biomechanical testing. In each group, two animals were randomly sacrificed at the twelfth week after surgery; a three-point bending test was performed using a biomechanical testing machine, and the results were compared with those of a normal radius. Results: The X-ray and histological examinations at 6 and 12 weeks after surgery revealed that the osteogenesis ability of the simvastatin biological bone and osteoblast-simvastatin biological bone was better than that of the osteoblast biological bone and simple biological bone, which was superior in group A and group B to group C and group D. The results of the biomechanical examination revealed that the maximum stress of the normal radius was significantly higher than that of the experimental groups. Among the experimental groups, the difference between group A and group B was not statistically significant, and the maximum stress was higher in groups A and B than in groups C and D. Conclusion: Simvastatin biological bone material can promote the repair of rabbit radius defects and increase the quality of bone healing.

STATINSWITH POTENTIAL TO CONTROL PERIODONTITIS: FROM BIOLOGICAL MECHANISMS TO CLINICAL STUDIES

BACKGROUND

Statins are widely used for the treatment of hyperlipidemia. However, these drugs have pleiotropic effects that can be promising for the prevention and treatment of oral diseases, such as periodontitis.

HIGHLIGHT

This review aimed to identify preclinical, observational, and clinical studies that evaluate the effects and biological mechanisms of statins on oral cells and tissues and those using these drugs to treat periodontitis. A LITERATURE SURVEY HAS BEEN CONDUCTED IN PUBMED USING COMBINATIONS OF THE UNITERMS: "statins," "dentistry," "periodontal disease," and "periodontal treatment." In vitro findings showed positive statin results in cell lines related to alveolar bone metabolism by altering the signaling pathway Osteoprotegerin/Receptor Activator of Nuclear Factor Kappa B/Receptor Activator of Nuclear Factor Kappa B Ligand (OPG/RANK/RANKL), stimulating the production of alkaline phosphatase and osteocalcin, and reducing the production of matrix metalloproteinases (MMPs). Animal studies have shown a reduction in alveolar bone loss and osteoclastic activity, in addition to a reduction in inflammatory markers, such as IL-1, IL-6, and TNF-α, when statins were used prophylactically. Clinical trials showed a positive impact on clinical parameters, leading to a higher reduction in probing depth and gain in clinical attachment when a local statin was adjunctively associated with mechanical therapy.

CONCLUSION

Statins were shown to be promising for regenerating and stimulating bone activity, with great potential for treating chronic periodontitis. However, further studies are required to confirm its effectiveness.

The effect of topical administration of simvastatin on entochondrostosis and intramembranous ossification: An animal experiment

Background

Simvastatin, a drug for lowering serum cholesterol, has been shown to enhance bone regeneration, but few studies have qualitatively and quantitatively tested its effect when used topically in different animal models. This study aims to investigate topical administration of simvastatin as a bone regeneration inducer by testing its effect on bone formation in both long tubular bone and flat bone defect, and the mechanism involved.

Methods

Two animal models were used for testing the effect of simvastatin on entochondrostosis and intramembranous ossification respectively. Simvastatin of different dosages combined with poly lactic acid were implanted in extreme radial defects of 12 adult male New Zealand rabbits. Bone formation was monitored using x-ray and CT-scan and measured using x-ray scales, pixel values and spiral CT-scan for 16 weeks before being subject to histological and immunohistochemistry examination. The result was compared with that of autograft and blank control groups. Simvastatin with thrombin and fibrin sealant were implanted in calvarial defects of three Rhesus monkeys and monitored for 18 weeks. Bone formation was compared between the simvastatin and the blank control group using spiral CT-scan and histological examination.

Results

Both visual and quantitative measurements by x-ray and spiral CT-scan indicated significant bone formation in radial defects in all simvastatin groups and the autograft group whereas no bone formation was found in control groups. There was no significant difference in bone formation quantity between 100 ​mg simvastatin and autograft. Histological and immunohistochemistry examination indicated entochondrostosis in association with positive expression of BMP-2 and HIF-1 alpha. Spiral CT-scan and histological examination of calvarial defects of monkeys showed intramembranous ossification after simvastatin implantation. No change was found in the control group.

Conclusions

Topical administration of simvastatin induces entochondrostosis and intramembranous ossification by enhancing expression of BMP-2 and HIF-1 alpha. The effect of simvastatin on bone regeneration is comparable to autograft.

The translational potential of this article

Topical administration of simvastatin can repair bone defect in both long tubular bones and flat bones of rabbits and monkeys as effectively as autograft. Given that it is cheap, safe and already in clinical use, simvastatin might be considered as a bone regeneration inducer with great potential.

Gan-Lu-Yin (Kanroin), Traditional Chinese Herbal Extracts, Reduces Osteoclast Differentiation In Vitro and Prevents Alveolar Bone Resorption in Rat Experimental Periodontitis

Gan-Lu-Yin (GLY), a traditional Chinese herbal medicine, shows therapeutic effects on periodontitis, but that mechanism is not well known. This study aims to clarify the precise mechanism by investigating the inhibitory effects of GLY extracts on osteoclastogenesis in vitro and on bone resorption in periodontitis in vivo. RAW264.7 cells are cultured with soluble receptor activator of nuclear factor-kappa B (sRANKL) and GLY extracts (0.01–1.0 mg/mL), and stained for tartrate-resistant acid phosphatase (TRAP) to evaluate osteoclast differentiation. Experimental periodontitis is induced by placing a nylon ligature around the second maxillary molar in rats, and rats are administered GLY extracts (60 mg/kg) daily for 20 days. Their maxillae are collected on day 4 and 20, and the levels of alveolar bone resorption and osteoclast differentiation are estimated using micro-computed tomography (CT) and histological analysis, respectively. In RAW264.7 cells, GLY extracts significantly inhibit sRANKL-induced osteoclast differentiation at a concentration of more than 0.05 mg/mL. In experimental periodontitis, administering GLY extracts significantly decreases the number of TRAP-positive osteoclasts in the alveolar bone on day 4, and significantly inhibits the ligature-induced bone resorption on day 20. These results show that GLY extracts suppress bone resorption by inhibiting osteoclast differentiation in experimental periodontitis, suggesting that GLY extracts are potentially useful for oral care in periodontitis.

Management of cracked tooth using simvastatin as intracanal medicament

Cracked tooth syndrome is presented as pain associated with biting and sensitivity. Intracanal medication with simvastatin stimulates hard tissue formation at crack line, and the tooth was functioning on the follow-ups.

Could medications and biologic factors affect post-orthodontic tooth movement changes? A systematic review of animal studies

Immediately after the removal of orthodontic appliances, the teeth might start to drift away from their corrected position in an attempt to reach a new equilibrium. Medications and biologic factors could potentially modulate these processes. The objective of the present systematic review is to systematically investigate and appraise the quality of the evidence regarding the effect of various medications and biologic factors on the rate of relapse following active tooth movement. Search without restrictions in eight databases and hand searching until April 2020 were conducted. Studies performed on animal models investigating the effects of medication and biologic factors on the rate of relapse following orthodontic tooth movement were considered. Following study retrieval and selection, relevant data were extracted and the risk of bias was assessed. Seventeen studies were finally identified, mostly at either high or unclear risk of bias. Ketorolac did not show any significant effects on relapse, while the administration of tetracycline, atorvastatin, psoralen and raloxifene decreased it. Overall, the same result was observed with bisphosphonates with the exception of low dosage of risedronate, which did not have an effect. Osteoprotegerin and strontium resulted in reduced relapse, but not in the immediate post-administration period. Inconsistent or conflicting effects were noted after the use of simvastatin and relaxin. The quality of the available evidence was considered at best as low. It can be concluded that specific medications and biologic factors may have an effect on the rate of relapse following tooth movement. The orthodontist should be knowledgeable about the substances potentially affecting retention.

The effects of statins on dental and oral health: a review of preclinical and clinical studies

The statin family of drugs are safe and effective therapeutic agents for the treatment of arteriosclerotic cardiovascular disease (CVD). Due to a wide range of health benefits in addition to their cholesterol lowering properties, statins have recently attracted significant attention as a new treatment strategy for several conditions, which are not directly related to normalizing a lipid profile and preventing CVD. Statins exert a variety of beneficial effects on different aspects of oral health, which includes their positive effects on bone metabolism, their anti-inflammatory and antioxidant properties, and their potential effects on epithelization and wound healing. Additionally, they possess antimicrobial, antiviral, and fungicidal properties, which makes this class of drugs attractive to the field of periodontal diseases and oral and dental health. However, to the best of our knowledge, there has been no comprehensive study to date, which has investigated the effects of statin drugs on different aspects of dental and oral health. Therefore, the primary objective of this paper was to review the effect of statins on dental and oral health. Results of our extensive review have indicated that statins possess remarkable and promising effects on several aspects of dental and oral health including chronic periodontitis, alveolar bone loss due to either extraction or chronic periodontitis, osseointegration of implants, dental pulp cells, orthodontic tooth movement, and orthodontic relapse, tissue healing (wound/bone healing), salivary gland function, and finally, anti-cancer effects. Hence, statins can be considered as novel, safe, inexpensive, and widely-accessible therapeutic agents to improve different aspects of dental and oral health.

Local effect of simvastatin combined with different osteoconductive biomaterials and collagen sponge on new bone formation in critical defects in rat calvaria

Purpose

To evaluate the local effect of simvastatin (SVT) combined with deproteinized bovine bone (DBB) with hydroxyapatite/β-tricalcium phosphate biphasic ceramics (HA/TCP) and with collagen sponge (CS) on bone repair in critical size defects (CSDs) in rat calvaria.

Methods

Forty-two 5-mm diameter CSDs were made bilaterally in the calvaria of 18 rats. The animals were allocated according to the type of biomaterial and associations used to fill the CSD. After 8 weeks, the animals were euthanized, and their calvaria were evaluated for repaired tissue composition using histologic and histometric analyses.

Results

In the histometric analysis, the use of SVT showed to increase bone formation in the CSDs when combined with all the bone substitutes tested in this study (p<0.05). Greater bone formation was observed in the groups with SVT compared to the groups without SVT.

Conclusions

The use of SVT without the need for a vehicle and combined with a commercially available biomaterial may be a cheaper way to potentiate the formation of bone tissue without the need to produce new biomaterials. Therefore, SVT combined with DBB induced significantly greater new bone formation than did the other treatments.

A low level of lysophosphatidic acid in human gingival crevicular fluid from patients with periodontitis due to high soluble lysophospholipase activity: Its potential protective role on alveolar bone loss by periodontitis

We previously detected a submicromolar concentration of lysophosphatidic acid (LPA) in human saliva. Here, we compare LPA concentrations in human gingival crevicular fluid (GCF) from patients with periodontitis and healthy controls, and examine how the local LPA levels are regulated enzymatically. The concentrations of LPA and its precursor lysophospholipids in GCF was measured by liquid chromatography-tandem mass spectrometry. The LPA-producing and LPA-degrading enzymatic activities were measured by quantifying the liberated choline and free fatty acid, respectively. The concentration of LPA in GCF of periodontitis patients was lower than that of healthy controls, due to higher soluble lysophospholipase activity toward LPA. LPA was found to prevent survival of Sa3, a human gingival epithelium-derived tumor cell line, activate Sa3 through Ca²⁺ mobilization, and release interleukin 6 from Sa3 in vitro. Furthermore, local injection of LPA into the gingiva attenuated ligature-induced experimental alveolar bone loss induced by oral bacteria inoculation in a rat model of periodontitis in vivo. A high concentration of LPA in human GCF is necessary to maintain normal gingival epithelial integrity and function, protecting the progression of periodontitis.

Evaluation of the clinical efficacy of 1.2% atorvastatin in the treatment of periodontal intraosseous defects by CBCT: A randomized controlled clinical trial

Background. Atorvastatin (ATV), which belongs to the statin class of drugs, is the formidable inhibitor of 3-hydroxy-2- methyl-glutaryl coenzyme A reductase. This clinical trial evaluated and compared the clinical and radiographic changes in chronic periodontitis (CP) patients, obtained through 1.2% ATV as an adjunct to scaling and root planing (SRP) in the treatment of intraosseous defects. Methods. Twenty CP patients, with a minimum of one pair of bilateral intraosseous, were randomly selected for this splitmouth study. Group 1 included 20 sites treated with SRP and subgingival delivery of a placebo gel, whereas an equal number of sites in group 2 were treated by SRP along with subgingival delivery of 1.2% ATV gel. The plaque index (PI), modified sulcus bleeding index (mSBI), probing pocket depth (PPD) and clinical attachment level (CAL) were evaluated at baseline and 3- and 6-month intervals, while the intraosseous defect was assessed at baseline and 6-month interval using cone-beam computed tomography (CBCT). Paired t-test was used to determine statistical significance. Results. A greater reduction in the mean PPD and gain in CAL was found in group 2 compared to group 1 at 3- and 6-month intervals. Furthermore, a significantly greater bone fill was obtained in group 2 (1.70±0.54 mm) compared to group 1 (0.22±0.43 mm) after six months. Conclusion. ATV, as an adjunct to SRP, enhanced periodontal regeneration, as a noninvasive way to treat periodontal intraosseous defects.

Contribution of Statins towards Periodontal Treatment: A Review

The pleiotropic effects of statins have been evaluated to assess their potential benefit in the treatment of various inflammatory and immune-mediated diseases including periodontitis. Herein, the adjunctive use of statins in periodontal therapy in vitro, in vivo, and in clinical trials was reviewed. Statins act through several pathways to modulate inflammation, immune response, bone metabolism, and bacterial clearance. They control periodontal inflammation through inhibition of proinflammatory cytokines and promotion of anti-inflammatory and/or proresolution molecule release, mainly, through the ERK, MAPK, PI3-Akt, and NF-κB pathways. Moreover, they are able to modulate the host response activated by bacterial challenge, to prevent inflammation-mediated bone resorption and to promote bone formation. Furthermore, they reduce bacterial growth, disrupt bacterial membrane stability, and increase bacterial clearance, thus averting the exacerbation of infection. Local statin delivery as adjunct to both nonsurgical and surgical periodontal therapies results in better periodontal treatment outcomes compared to systemic delivery. Moreover, combination of statin therapy with other regenerative agents improves periodontal healing response. Therefore, statins could be proposed as a potential adjuvant to periodontal therapy. However, optimization of the combination of their dose, type, and carrier could be instrumental in achieving the best treatment response.

Does common prescription medication affect the rate of orthodontic tooth movement? A systematic review

Background

As the taking of any medication may theoretically affect the complex pathways responsible for periodontal tissue homeostasis and the events leading to orthodontic tooth movement, it is considered important for the orthodontist to be able to identify prospective patients' history and patterns of pharmaceutical consumption.

Objective

To systematically investigate and appraise the quality of the available evidence regarding the effect of commonly prescribed medications on the rate of orthodontic tooth movement.

Search methods

Search without restrictions in eight databases and hand searching until June 2017.

Selection criteria

Controlled studies investigating the effect of commonly prescribed medications with emphasis on the rate of orthodontic tooth movement.

Data collection and analysis

Following study retrieval and selection, relevant data was extracted and the risk of bias was assessed using the SYRCLE's Risk of Bias Tool.

Results

Twenty-seven animal studies, involving various pharmacologic and orthodontic interventions, were finally identified. Most studies were assessed to be at unclear or high risk of bias. The rate of orthodontic tooth movement was shown to increase after the administration of diazepam, Vitamin C and pantoprazole, while simvastatin, atorvastatin, calcium compounds, strontium ranelate, propranolol, losartan, famotidine, cetirizine, and metformin decreased the rate of orthodontic tooth movement. No interference with the rate of orthodontic tooth movement was reported for phenytoin, phenobarbital and zinc compounds, whereas, inconsistent or conflicting effects were noted after the administration of L-thyroxine, lithium compounds, fluoxetine and insulin. The quality of the available evidence was considered at best as low.

Conclusions

Commonly prescribed medications may exhibit variable effects on the rate of orthodontic tooth movement. Although the quality of evidence was considered at best as low, raising reservations about the strength of the relevant recommendations, the clinician should be capable of identifying patients taking medications and should take into consideration the possible implications related to the proposed treatment.

Registration

PROSPERO (CRD42015029130).

Effects of statins on multispecies oral biofilm identify simvastatin as a drug candidate targeting Porphyromonas gingivalis

BACKGROUND

Statins effectively reduce risk of cardiovascular-related morbidity and mortality in patients with hyperlipidemia, hypertension, or type 2 diabetes. In addition to lowering cholesterol levels, several studies have attributed statins with immunomodulatory and bactericidal properties. Therefore, the aim of this study was to investigate statins' antimicrobial activity against periodontal homeostasis bacteria.

METHODS

Statin effect on bacterial growth was tested using planktonic monocultures and multibacterial biofilms. The latter consisted of five microbial species (Porphyromonas gingivalis, Fusobacterium nucleatum, Actinomyces naeslundii, Tannerella forsythia, and Streptococcus gordonii) associated with dysbiosis of the oral microbiota underlying establishment and perpetuation of periodontitis.

RESULTS

All four tested statins efficiently inhibited P. gingivalis growth and significantly decreased the cumulative bacterial load in developing and established biofilms. Simvastatin was most efficient and decreased P. gingivalis counts more than 1,300-fold relative to the control.

CONCLUSIONS

These findings suggest that similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microbiome from a dysbiotic to a more homeostatic one. Simvastatin, being highly effective against P. gingivalis while not affecting commensal microbiota, possesses many properties qualifying it as a potential adjunctive treatment for chronic periodontitis. Further studies are needed to evaluate whether similar effects on bacterial composition of the dental plaque may occur in vivo in patients on statins, thus, leading to a shift of the oral microflora from dysbiotic to a more homeostatic one.

Statins in nonsurgical and surgical periodontal therapy. A systematic review and meta-analysis of preclinical in vivo trials

The cholesterol-lowering drugs, statins, possess anti-inflammatory, antimicrobial and pro-osteogenic properties, and thus have been tested as an adjunct to periodontal treatment. The present systematic review aimed to answer the following focused research question: What is the effect of local and/or systemic statin use on periodontal tissues in preclinical in vivo studies of experimentally induced periodontitis (EIP) and/or acute/chronified periodontal defect (ACP) models? A literature search (of Medline/PubMed, Embase/Ovid, CENTRAL/Ovid) using the following main eligibility criteria was performed: (i) English or German language; (ii) controlled preclinical in vivo trials; (iii) local and/or systemic statin use in EIP and/or ACP models; and (iv) quantitative evaluation of periodontal tissues (i.e., alveolar bone level/amount, attachment level, cementum formation, periodontal ligament formation). Sixteen studies in EIP models and 7 studies in ACP models evaluated simvastatin, atorvastatin or rosuvastatin. Thirteen of the EIP (81%) and 2 of the ACP (29%) studies presented significantly better results in terms of alveolar bone level/amount in favor of statins. Meta-analysis based on 14 EIP trials confirmed a significant benefit of local and systemic statin use (P < .001) in terms of alveolar bone level/amount; meta-regression revealed that statin type exhibited a significant effect (P = .014) in favor of atorvastatin. Three studies reported a significantly higher periodontal attachment level in favor of statin use (P < .001). Complete periodontal regeneration was never observed; furthermore, statins did not exert any apparent effect on cementum formation. Neither local nor systemic use of statins resulted in severe adverse effects. Statin use in periodontal indications has a positive effect on periodontal tissue parameters, supporting the positive results already observed in clinical trials. Nevertheless, not all statins available have been tested so far, and further research is needed to identify the maximum effective concentration/dose and optimal carrier.

Role of Simvastatin on fracture healing and osteoporosis: a systematic review on in vivo investigations

Simvastatin is a lipid lowering drug whose beneficial role on bone metabolism was discovered in 1999. Several in vivo studies evaluated its role on osteoporosis and fracture healing, however, controversial results are seen in the literature. For this reason, Simvastatin has not been the focus of any clinical trials as yet. This systematic review clears the mechanisms of action of Simvastatin on bone metabolism and focuses on in vivo investigations that have evaluated its role on osteoporosis and fracture repair to find out (i) whether Simvastatin is effective on treatment of osteoporosis and fracture repair, and (ii) which of the many available protocols may have the ability to be translated in the clinical setting. Simvastatin induces osteoinduction by increasing osteoblast activity and differentiation and inhibiting their apoptosis. It also reduces osteoclastogenesis by decreasing both the number and activity of osteoclasts and their differentiation. Controversial results between the in vivo studies are mostly due to the differences in the route of administration, dose, dosage and carrier type. Local delivery of Simvastatin through controlled drug delivery systems with much lower doses and dosages than the systemic route seems to be the most valuable option in fracture healing. However, systemic delivery of Simvastatin with much higher doses and dosages than the clinical ones seems to be effective in managing osteoporosis. Simvastatin, in a particular range of doses and dosages, may be beneficial in managing osteoporosis and fracture injuries. This review showed that Simvastatin is effective in the treatment of osteoporosis and fracture healing.

Effect of in-situ application of simvastatin gel in surgical management of osseous defects in chronic periodontitis-A randomized clinical trial

BACKGROUND

The present randomized controlled clinical study was designed to investigate the effect of in situ application of 1.2 mg Simvastatin (SV) gel in the surgical management of Intrabony defects in chronic periodontitis patients.

METHODOLOGY

20 patients contributing 40 sites were categorized into two treatment groups: Open flap debridement plus 1.2 mg SV gel (Group 1) and Open flap debridement plus Placebo gel (Group 2). Gingival index (GI), Plaque index (PI), Pocket depth (PD) and clinical attachment level (CAL) were recorded at baseline, 3 months, 6 months and 9 months. At baseline and at the end of 6 and 9 months Radiographic evaluation of Intrabony defect fill was done using Image j software.

RESULTS

Significant reduction of GI, PD and gain in CAL was observed at the end of 9 months in both groups. Amount of bone fill and percentage of original defect fill in Group 1 was statistically highly significant than Group 2 at the end of 6 and 9 months.

CONCLUSION

Higher amount of decrease in GI and PD along with more amount of CAL gain was observed in treatment group than control group. Radiological assessment confirmed that significant intrabony defect fill and percentage fill of original defect in treatment group than controlled group.

Simvastatin and biphasic calcium phosphate affects bone formation in critical-sized rat calvarial defects

PURPOSE

To investigate the effects of locally applied simvastatin plus biphasic calcium phosphate (BoneCeramic(r)) or collagen sponge on bone formation in critical-sized bone defects.

METHODS

Thirty defects of 5mm in diameter were created bilaterally with a trephine bur in the calvariae of fifteen Wistar rats. The defects were divided into five groups: group 1 - control, no treatment; group 2 (BoneCeramic(r)); group 3 (BoneCeramic(r) + 0.1mg simvastatin); group 4 (collagen sponge); and group 5 (collagen sponge + 0.1mg simvastatin). After eight weeks the animals were euthanized and their calvariae were histologically processed. Hematoxylin and eosin-stained sections were subjected to histological and histomorphometrical analyses. The area of newly formed bone was calculated and compared between groups.

RESULTS

The greater amount of a bone-like tissue was formed around the carrier in group 3 (BoneCeramic(r) + 0.1mg simvastatin) followed by group 2 (BoneCeramic(r)), and almost no bone was formed in the other groups. Group 3 was significantly different compared to group 2, and both groups were significantly different compared to the other groups.

CONCLUSION

Simvastatin combined with BoneCeramic(r) induced significantly greater amounts of newly formed bone and has great potential for the healing of bone defects.

Evaluation of the effects of subgingival injection of Simvastatin on space re-opening after orthodontic space closure in adults

Background. This clinical trial evaluated the effect of Simvastatin on space re-opening after orthodontic space closure and its effect on the gingival index (GI) and clinical attachment loss (CAL). Methods. 16 females, 25-40 years old, with spaces between anterior mandibular teeth due to chronic periodontitis were participated in this study. The patients were randomly divided into control and experimental groups. In the experimental group, 1.2% Simvastatin gel and in the control group, 0.9% sodium chloride as a placebo was injected into the pocket depth of the six anterior teeth. The amount of space reopening, GI and CAL were measured. Results. No serious complications were observed during interventions and follow-up periods. Space re-opening was significantly reduced in patients receiving Simvastatin (P < 0.001). Moreover, GI reduction was significantly greater in Sim-vastatin group compared to the control group (P < 0.001). However, CAL did not demonstrate a significant difference between the groups. Conclusion. Simvastatin may decrease space re-opening after orthodontic space closure in human anterior teeth.

Controlled-release of tetracycline and lovastatin by poly(D,L-lactide-co-glycolide acid)-chitosan nanoparticles enhances periodontal regeneration in dogs

Chronic periodontitis is characterized by inflammation of periodontal tissues, leading to bone resorption and tooth loss. The goal of treatment is to regenerate periodontal tissues including bone and cementum lost as a consequence of disease. The local delivery of tetracycline was proven to be effective in controlling localized periodontal infection without apparent side effects. Previous studies suggested that lovastatin has a significant role in new bone formation; however, the local delivery of lovastatin might enhance its therapeutic effects. A number of local delivery devices have been developed recently, including poly(D,L-lactide-co-glycolide acid) (PLGA) nanoparticles. The aim of this study was to develop a local delivery device, PLGA-lovastatin-chitosan-tetracycline nanoparticles, which allows the sequential release of tetracycline and lovastatin to effectively control local infection and promote bone regeneration in periodontitis. The size and microstructure of nanoparticles were examined by transmission electron microscopy, Nanoparticle Size Analyzer, and Fourier transform infrared spectroscopy. The release of tetracycline and lovastatin was quantified using a UV-Vis spectrophotometer. Furthermore, the cytotoxic effect and alkaline phosphatase activity of the nanoparticles in osteoblast cell cultures as well as antibacterial activity against periodontal pathogens were investigated. Finally, the bone regeneration potential of PLGA nanoparticles in three-walled defects in beagle dogs was investigated. The results indicated that PLGA-lovastatin-chitosan-tetracycline nanoparticles showed good biocompatibility, antibacterial activity, and increased alkaline phosphatase activity. The volumetric analysis from micro-CT revealed significantly increased new bone formation in defects filled with nanoparticles in dogs. This novel local delivery device might be useful as an adjunctive treatment in periodontal regenerative therapy.

Effect of topical simvastatin (1.2 mg) on gingival crevicular fluid interleukin-6, interleukin-8 and interleukin-10 levels in chronic periodontitis - A clinicobiochemical study

OBJECTIVES

The impact of simvastatin (SMV), a cholesterol lowering drug, on bone metabolism appears to involve complex interaction with cholesterol metabolites, hormones, inflammatory mediators and growth factors, thus having direct influence on extent and severity of periodontitis. The present study aims to evaluate the in vivo effect of subgingivally delivered SMV gel (1.2 mg) as a local drug-delivery agent on clinical parameters and on interleukin-6 (IL-6), interleukin-8 (IL-8) and interleukin-10 (IL-10) levels in gingival crevicular fluid (GCF) of chronic periodontitis patients.

MATERIALS AND METHODS

50 patients were selected and categorized into two treatment groups: control (scaling and root planing) and test group (scaling and root planing with SMV gel). At initial appointment, clinical parameters were measured. Biochemical analysis of GCF samples was done to evaluate the amount of IL-6, IL-8 and IL-10. GCF sampling and clinical parameters were repeated at one and three months for both the groups.

RESULTS

SMV has an inhibitory effect on pro-inflammatory cytokines (IL-6, IL-8) and stimulatory effect on anti-inflammatory cytokines (IL-10) in GCF of periodontitis patients and has significantly positive effect on all clinical parameters except relative attachment level (RAL). The addition of SMV, thereby, further alters the levels of cytokine that reflect enhanced antibacterial host defence activity at that site.

CONCLUSION

Topical SMV has a beneficial effect on periodontal health. Removal of the bacterial plaque and subgingival delivery of SMV significantly modulates the chemokines present in GCF. To summarize, SMV shows promising role in the management of periodontitis.

Simvastatin prodrug micelles target fracture and improve healing

Simvastatin (SIM), a widely used anti-lipidemic drug, has been identified as a bone anabolic agent. Its poor water solubility and the lack of distribution to the skeleton, however, have limited its application in the treatment of bone metabolic diseases. In this study, an amphiphilic macromolecular prodrug of SIM was designed and synthesized to overcome these limitations. The polyethylene glycol (PEG)-based prodrug can spontaneously self-assemble to form micelles. The use of SIM trimer as the prodrug's hydrophobic segment allows easy encapsulation of additional free SIM. The in vitro studies showed that SIM/SIM-mPEG micelles were internalized by MC3T3 cells via lysosomal trafficking and consistently induced expression of both BMP2 and DKK1 mRNA, suggesting that the prodrug micelle retains the biological functions of SIM. After systemic administration, optical imaging suggests that the micelles would passively target to bone fracture sites associated with hematoma and inflammation. Furthermore, flow cytometry study revealed that SIM/SIM-mPEG micelles had preferred cellular uptake by inflammatory and resident cells within the fracture callus tissue. The treatment study using a mouse osteotomy model validated the micelles' therapeutic efficacy in promoting bone fracture healing as demonstrated by micro-CT and histological analyses. Collectively, these data suggest that the macromolecular prodrug-based micelle formulation of SIM may have great potential for clinical management of impaired fracture healing.

Efficacy of Simvastatin in Bone Regeneration After Surgical Removal of Mandibular Third Molars: A Clinical Pilot Study

INTRODUCTION

Simvastatin, a common cholesterol-lowering drug that inhibits hepatic hydroxymethylglutaryl coenzyme A reductase, the rate-limiting enzyme in the mevalonate pathway, increases expression of the BMP-2 gene and thus promotes bone regeneration.

MATERIALS AND METHODS

A study was conducted in mandibular third molar sockets to study the efficacy of the drug by implanting it into sockets (experimental group) and observations were made over 3 months to compare the healing with the (control group).

CONCLUSION

The results showed faster regeneration of the bone in the simvastatin site using the gray level histogram values.

Statins and alveolar bone resorption: a narrative review of preclinical and clinical studies

CONTEXT

Tooth extraction and periodontal disease are both common clinical situations associated with alveolar bone loss.

OBJECTIVE

To analyze the reported results of in vivo studies investigating the effectiveness of statins to reduce alveolar bone resorption.

STUDY DESIGN

Systematic electronic search of the MEDLINE-PubMed database.

RESULTS

A total of 21 studies met the inclusion criteria. This review showed that the use of statins reduced significantly alveolar bone resorption observed during periodontal disease and after tooth extraction. Oral administration was effective using high statin concentrations, although local administration using a biodegradable carrier was effective with lower concentrations. It was recently reported that statins were effective to reduce alveolar bone loss as an adjunct to scaling and root planing (SRP) in several clinical trials. Further studies are needed to confirm these promising results.

Simvastatin prevents alveolar bone loss in an experimental rat model of periodontitis after ovariectomy

Background

Periodontitis is an inflammatory disease characterized by the loss of connective tissue and alveolar bone. There is an increasing evidence that periodontitis is associated with a number of chronic disease, including osteoporosis. Periodontitis and osteoporosis are both bone destructive diseases and of high prevalence in adult population. Osteoporosis could increase some inflammatory factors that also participate in the progression of periodontitis, so as to facilitate the alveolar bone resorption. Simvastatin, specific inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme reductase, is of pleiotropic effects including anti-catabolic and anabolic effect on bone metabolism. This study aimed to explore the local and systemic effect of simvastatin on maxillary in rats with both osteoporosis and periodontitis.

Methods

Thirty-six 4-month-old female Sprague Dawley rats were randomly assigned to six groups: sham group, ligature group, ovariectomized (OVX) + ligature group, local simvastatin administration to OVX + ligature rats (local simvastatin group), oral simvastatin administration to OVX + ligature rats (oral simvastatin group), local and oral simvastatin administration to OVX + ligature rats (L&O simvastatin group). One month after OVX, ligatures were placed on the maxillary first (M1) and second molars (M2) for 4 weeks on all rats except those in the sham group, followed by simvastatin treatment for 2 months. The maxillae, serum, and femurs were collected for further examination including micro-computed (micro-CT) tomography, hematoxylin and eosin (H&E) staining, tartrate-resistant acid phosphatase (TRAP) staining, enzyme-linked immunosorbent assays (ELISA), and the three-point bending test.

Results

Local simvastatin administration increased alveolar crest height and prevented local alveolar bone loss without alteration of systemic bone loss. Oral administration prevented local and systemic bone loss with no effect on alveolar crest height.

Conclusions

Our results indicate that simvastatin has the potential of promoting bone formation and reducing alveolar bone loss in maxillary following ovariectomy (OVX) and ligature placement in rats.

Statins, bone metabolism and treatment of bone catabolic diseases

The discovery that statins had bone anabolic properties initiated many investigations into their use for treatment of bone catabolic diseases, such as osteoporosis. This paper reviews the molecular basis of statin's role in bone metabolism, and animal and human studies on the impact of systemic statins on osteoporosis-induced bone fracture incidence and healing, and on bone density. Limitations of systemic statins are described along with alternative dosing strategies, including local applications and bone-targeting systemic preparations. The principal findings of this review are: (1) traditional oral dosing with statins results in minimal efficacy in the treatment of osteoporosis; (2) local applications of statins show promise in the treatment of accessible bony defects, such as periodontitis; and (3) systemically administered statins which can target bone or inflammation near bone may be the safest and most effective strategy in the treatment of osseous deficiencies.

Tooth loss, periodontitis, and statins in a population-based follow-up study

BACKGROUND

Statins, frequently prescribed in lipid-lowering therapies, seem to have additional beneficial effects on periodontitis and tooth loss. If this is true, then chronic treatment with statins should also result in diminished tooth loss as a long-term response.

METHODS

A 5-year population-based follow-up study of tooth loss was performed comparing participants treated with statins (n = 134) with those not on the drugs (Study of Health in Pomerania). Negative binomial regression models were used to analyze the count variable of the outcome, including risk factors for tooth loss and measures of cholesterol metabolism.

RESULTS

When adjusted for age and sex, statins were associated with reduced tooth loss during the follow-up period (incidence risk ratio [IRR] = 0.70, 95% confidence interval [CI] = 0.50 to 0.99, P = 0.04). When additionally adjusted for risk factors of periodontal breakdown, IRR was 0.72 (95% CI = 0.52 to 1.01). There was significant interaction with low-density lipoprotein cholesterol (LDL-c) at baseline. After stratification by LDL-c, statins were associated with reduced tooth loss, resulting in IRR = 0.89 (95% CI = 0.44 to 1.83) and 0.64 (95% CI = 0.43 to 0.95), P = 0.03, at LDL-c concentrations ≤100 mg/dL and >100 mg/dL (2.58 mmol/L), respectively. The data also showed reduced tooth loss associated with the 5-year reduction in LDL-c levels on a mmol/L basis and independently of statins (IRR = 0.87, 95% CI = 0.80 to 0.96, P = 0.004).

CONCLUSION

Long-term treatment with systemically administered statins may have the beneficial effect of protecting against tooth loss.

Design of a multiple drug delivery system directed at periodontitis

Periodontal disease is highly prevalent, with 90% of the world population affected by either periodontitis or its preceding condition, gingivitis. These conditions are caused by bacterial biofilms on teeth, which stimulate a chronic inflammatory response that leads to loss of alveolar bone and, ultimately, the tooth. Current treatment methods for periodontitis address specific parts of the disease, with no individual treatment serving as a complete therapy. The present research sought to demonstrate development of a multiple drug delivery system for stepwise treatment of different stages of periodontal disease. More specifically, multilayered films were fabricated from an association polymer comprising cellulose acetate phthalate and Pluronic F-127 to achieve sequential release of drugs. The four types of drugs used were metronidazole, ketoprofen, doxycycline, and simvastatin to eliminate infection, inhibit inflammation, prevent tissue destruction, and aid bone regeneration, respectively. Different erosion times and adjustable sequential release profiles were achieved by modifying the number of layers or by inclusion of a slower-eroding polymer layer. Analysis of antibiotic and anti-inflammatory bioactivity showed that drugs released from the devices retained 100% bioactivity. The multilayered CAPP delivery system offers a versatile approach for releasing different drugs based on the pathogenesis of periodontitis and other conditions.

Platelet-rich plasma, plasma rich in growth factors and simvastatin in the regeneration and repair of alveolar bone

Platelet preparations promote bone regeneration by inducing cell migration, proliferation and differentiation in the area of the injury, which are essential processes for regeneration. In addition, several studies have indicated that simvastatin (SIMV), widely used for the treatment of hypercholesterolemia, stimulates osteogenesis. The objective of this study was to evaluate the effects of treatment with either platelet-rich plasma (PRP) or plasma rich in growth factors (PRGF) in combination with SIMV in the regeneration and repair of alveolar bone. The jaws of Sprague Dawley rats (n=18) were subjected to rotary instrument-induced bone damage (BD). Animals were divided into six groups: BD/H₂O (n=3), distilled water without the drug and alveolar bone damage; BD/H₂O/PRP (n=3), BD and PRP; BD/H₂O/PRGF (n=3), BD and PRGF; BD/SIMV (n=3), BD and water with SIMV; BD/SIMV/PRP (n=3), BD, PRP and SIMV; and BD/SIMV/PRGF (n=3), BD, PRGF and SIMV. Conventional histological analysis (hematoxylin and eosin staining) revealed that the BD/SIMV group showed indicators for mature bone tissue, while the BD/SIMV/PRP and BD/SIMV/PRGF groups showed the coexistence of indicators for mature and immature bone tissue, with no statistical differences between the platelet preparations. Simvastatin did not improve the effect of platelet-rich plasma and plasma rich in growth factors. It was not possible to determine which platelet preparation produced superior effects.

The pleotropic role of statins: Could it be the imminent host modulation agent in periodontics?

Periodontal disease is a chronic inflammatory disease which represents a primarily anaerobic Gram-negative oral infection that results in gingival inflammation, loss of attachment, bone destruction. Bacterial endotoxins in the form of lipopolysaccharides (LPS) that are instrumental in generating a host-mediated tissue destructive immune response by mobilizing their defensive cells and releasing cytokines like Interleukin-1β (IL-1β), Tumor Necrosis Factor-α (TNF-α), and Interleukin-6 (IL-6), which lead to tissue destruction by stimulating the production of the collagenolytic enzymes: Matrix metalloproteinases (MMPs). Since the host-mediated tissue destruction is to be controlled, various means have been employed for modulating this response. Statins, 3-hydroxy-3-methylglutarylcoenzyme A (HMG CoA) reductase inhibitors, besides having lipid-lowering abilities also have antioxidant, antithrombotic, anti-inflammatory, immunomodulatory and osteomodulatory properties. All of these pleiotropic effects of statins point out to it perhaps becoming the novel host modulation agent in periodontics.

Assessment of vascular endothelial growth factor and matrix metalloproteinase-9 in the periodontium of rats treated with atorvastatin

BACKGROUND

The aim of this study is to examine, for the first time, the role of systemic and local atorvastatin application on periodontium using histomorphometric and immunohistochemical analysis during and after experimental periodontitis induction with or without the presence of microbial dental biofilm.

METHODS

One hundred ten male Wistar rats were used. Silk ligatures were placed around the cervical area of the mandibular first molars; rats in the healthy control group received no ligatures (n = 10). In experimental periodontitis groups (n = 90), systemic and local atorvastatin and saline were administered in three different periods; the control periodontitis group (n = 10) received no treatment. Histomorphometric analysis, which included alveolar bone area, alveolar bone level, and attachment loss, and immunohistochemical analysis, which included immunoreactivity of vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-9, were performed after the rats were sacrificed at the end of the experimental procedure.

RESULTS

There was a greater increase in alveolar bone area and VEGF immunoreactivity, as well as a greater decrease in alveolar bone and attachment loss and MMP-9 immunoreactivity, with systemic and local atorvastatin application during and after induction of experimental periodontitis. Local atorvastatin application showed better results on periodontium with regard to alveolar bone findings.

CONCLUSIONS

Systemic and local atorvastatin application showed beneficial effects on periodontium during and after induction of experimental periodontitis. Within the limits of this study, it can be concluded that atorvastatin, which is used for hypercholesterolemia treatment, can also be used as a protective and therapeutic agent for periodontal disease.

Simvastatin-activated implant surface promotes osteoblast differentiation in vitro

The bone growth promoting effects of statins suggest that these bioactive molecules can be used to improve the integration of bone-anchored implants. This study aimed at the application of simvastatin with dental implants for use in patients with low bone density. Coin-shaped titanium zirconium samples with grit-blasted and acid-etched surface were coated with simvastatin, using a novel anodic oxidation setup under alkaline conditions. The presence of intact simvastatin attached to the surface was confirmed by infrared spectroscopy. A binding site on the aliphatic O-H group was discovered and the integration of (1)H, (18)O and (12)C in the depth of the surface were observed by secondary ion mass spectroscopy. A simvastatin concentration of about 60 g/cm(2) was found in a release study over 72 h. The simvastatin-coated surfaces promoted alkaline phosphatase, collagen type I and osteocalcin gene expression of MC3T3-E1 cells. This suggested that the demonstrated coating holds potential for use in patients with compromised bone.

Simvastatin versus Calcium Hydroxide Direct Pulp Capping of Human Primary Molars: A Randomized Clinical Trial

Background and aims

The aim of present study was to investigate pulp-dentin complex reactions following direct pulp capping (DPC) with calcium hydroxide [Ca(OH)₂] and simvastatin as pulp-capping materials in the primary human molars.

Materials and methods

120 primary molar teeth which had to be extracted for orthodontic reasons were randomly allocated into four groups. Group Ι as a control, underwent DPC with calcium hydroxide. The dental pulp in group ІІ, ІІІ and ІV were directly capped with simvastatin-based materials at concentrations of 1, 5 and 10 µM, respectively. All of the teeth were restored with stainless steel crown. After a mean period of 7.41 months teeth were extracted and processed for histological examination and categorized in terms of hard tissue formation and pulp inflammation.

Results

Teeth in group I had statistically favorable outcomes in hard tissue formation and pulp inflammation than did the groups ІІ, ІІІ and ІV (P < 0.001). Considering three different concentrations of simvastatin, the result showed a dose dependent trend. Teeth in group ІV showed significantly lower rates of hard tissue formation and higher rates of pulp inflammation and necrosis compared to those of groups ІІ (P < 0.05).

Conclusion

The findings of this study depicted that healing with no inflammation and hard tissue formation following statin treatment occurs with a lower rate than that with the calcium hydroxide.

Novel and often bizarre strategies in the treatment of periodontal disease

Treatment of periodontal disease involves complex mechanical, surgical, and medical modalities. Some of the treatment regimens are patient centered, some involve a great amount of technical expertise and competence from a practitioner, and often involve complex procedures like use of tissue-engineered products. In spite of several advances, treatment of periodontal disease depends on scaling and root planing and various surgical procedures as the mainstay, but results of treatment are not always predictable and are often frustrating. The ultimate aim of periodontal treatment is regeneration of periodontal tissues and more particularly lost alveolar bone support. The treatment options include a myriad of approaches and scientists and researchers have tried various tools and agents to improve alveolar bone status and improve periodontal health. These approaches vary from simple monotherapy with systemic antibiotic usage to exotic and novel procedures like shock wave therapy, photodynamic therapy and application.

Periodontal status and hyperlipidemia: statin users versus non-users

BACKGROUND

The association between serum lipids and periodontal disease has been studied predominantly in patients with chronic periodontitis with limited data available regarding periodontal status of patients with hyperlipidemia. Meanwhile, the impact of statins on the periodontal health of the population also remains largely underexplored. This study aims to assess the periodontal status among patients with hyperlipidemia and users of statins.

METHODS

In this cross-sectional study, 94 patients with hyperlipidemia (50 receiving statins and 44 receiving non-pharmacologic therapy) and 46 control individuals who were normolipidemic underwent periodontal examination (plaque index, gingival index [GI], probing depth [PD], and clinical attachment level [CAL]). Biochemical parameters measured included serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein cholesterol levels.

RESULTS

PD and GI were significantly higher in patients with hyperlipidemia who were non-statin users compared with the normolipidemic individuals (P <0.001 [PD] and P <0.05 [GI]) and the statin group (P = 0.001 [PD] and P <0.05 [GI]). Periodontal parameters between statin users and the normolipidemic group did not differ significantly. After adjusting for confounders, positive and significant correlations were observed between PD and TG, and TC and LDL, whereas CAL shared correlation with TC and LDL. GI was correlated with TG and TC. Regression analyses revealed that whereas TC was associated significantly with PD (P <0.001), LDL showed significant association with CAL (P = 0.013). TG showed significant association with GI (P = 0.020).

CONCLUSIONS

Our findings suggest that relative to the general population, patients with hyperlipidemia are more prone to periodontal disease. Also, within the limits of this study, statins have a positive impact on periodontal health.

Impact of local and systemic alendronate on simvastatin-induced new bone around periodontal defects

BACKGROUND

Simvastatin has been shown to stimulate new bone growth on rat mandibles, but much of the bone is lost over time. The purpose of this study is to evaluate the impact of a locally or systemically applied antiresorptive agent (alendronate) on simvastatin-induced bone formation in and adjacent to a rat periodontal defect.

METHODS

Fenestration defects were created over mandibular molar roots in 65 mature female Sprague-Dawley rats. Two weeks later, animals were divided into eight groups of eight to nine rats, and three weekly injections around the defect were applied: 1) 0.5 mg simvastatin in ethanol (SIM-EtOH); 2) 0.5 mg simvastatin in alendronate-cyclodextrin conjugate (SIM-ALN-CD); 3) EtOH alone; 4) ALN-CD alone; or 5) no injections. Twenty-four animals were evaluated for new bone width around the defect 21 days after the last injections (short-term) and 41 rats were followed for 48 days (long-term). Three SIM-EtOH groups of long-term rats also were subjected to 2 weeks of daily systemic ALN or saline either during or 3 to 4 weeks after SIM-EtOH injections. Decalcified, hematoxylin-and-eosin-stained cross-sections of the defect area were analyzed for new bone width and groups were compared using mixed-model analyses of variance.

RESULTS

All groups showed nearly 100% bone fill, with no differences among the short-term groups. However, in the long-term animals, two-fold to three-fold more new bone width (≤ 0.004) was seen around the periphery of the defect with the use of systemic ALN after SIM-EtOH injections (0.93 ± 0.12 and 0.78 ± 0.11 mm with early and late systemic ALN, respectively) compared to local SIM/ALN-CD preparations (0.32 ± 0.10 mm) or short-term SIM-EtOH injections (0.35 ± 0.10 mm). No significant new cementum formation or ankylosis was noted.

CONCLUSION

The use of a short course of systemic ALN during the healing period after bone anabolic SIM injections has the potential to enhance local bone augmentation.

Highly efficient release of lovastatin from poly(lactic-co-glycolic acid) nanoparticles enhances bone repair in rats

Lovastatin exhibits higher thermal stability and lower degradation rate than simvastatin. However, the amount of research studying a lovastatin delivery device has been far less than similar research on simvastatin. As a consequence, a high lovastatin release rate system has not been developed. We hypothesized that highly efficient release of lovastatin from poly(lactic-co-glycolic acid) (PLGA) nanoparticles in a short-term release (7 days) could provide an effective delivery system for bone repair. This study optimized the emulsion (o/w) technique in the fabrication process for PLGA nanoparticles, thereby producing the first recorded case of a high release rate (97%) of lovastatin. We also calculated the calibration curve of lovastatin using a UV spectrometer. The results demonstrated that the ALPase activity in human osteoblasts could be significantly stimulated by lovastatin carried in PLGA nanoparticles, but was prominently decreased by free lovastatin with the concentration higher than 4 µg/ml. Animal studies showed that the amount of lovastatin contained in 1 mg PLGA was the optimum dosage. These results suggest the new lovastatin-releasing PLGA delivery device exhibits potential for clinical treatment of bony defects.

Topical and intermittent application of parathyroid hormone recovers alveolar bone loss in rat experimental periodontitis

BACKGROUND AND OBJECTIVE

Periodontitis is characterized by periodontal tissue inflammation and alveolar bone loss. The intermittent administration of parathyroid hormone (PTH), a major regulator of bone remodeling, has been demonstrated to stimulate osteoblastic activity. Although the systemic administration of PTH has been reported to protect against periodontitis-associated bone loss, the effect of the topical administration of PTH is unclear. In this study, the effect of intermittent administration of PTH on osteoblastic differentiation was examined in cultured calvaria cells and then the effect of topical and intermittent administration of PTH was determined by measuring the recovery of alveolar bone loss after inducing experimental periodontitis in rats.

MATERIAL AND METHODS

Alkaline phosphatase activity and bone nodule formation were measured in fetal rat calvaria cells. Experimental periodontitis was induced by placing nylon ligature around rat maxillary molars for 20 d. After ligature removal (day 0), PTH was topically injected into buccal gingiva three times a week for 10 wk. Micro-computed tomography analysis and histological examination were performed on days 35 and 70.

RESULTS

Intermittent exposure of PTH in calvaria cells increased alkaline phosphatase activity and bone nodule formation by 1.4- and 2.4-fold, respectively. Ligature procedures induced marked alveolar bone loss around the molars on day 0 and greater bone recovery was observed in the PTH-treated rats on day 70. An increase in osteoid formation on the surface of alveolar bone was detected in the PTH-treated rats.

CONCLUSION

Intermittent treatment with PTH stimulated osteoblastic differentiation in fetal rat calvaria cell cultures, and topical and intermittent administration of PTH recovered alveolar bone loss in rat experimental periodontitis.