Bisphosphonate treatment: An orthodontic concern calling for a proactive approach

Influence of zoledronic acid and pamidronate on tooth eruption in children with osteogenesis imperfecta

INTRODUCTION

Osteogenesis imperfecta (OI) is a congenital disease comprising a heterogeneous group of inherited connective tissue disorders. The main treatment in children is bisphosphonate therapy. Previous animal studies have shown that bisphosphonates delay tooth eruption. The aim of this study is to determine whether patients with OI treated with pamidronate and/or zoledronic acid have a delayed eruption age compared to a control group of healthy children.

METHODS

An ambispective longitudinal cohort study evaluating the age of eruption of the first stage mixed dentition in a group of children with OI (n = 37) all treated with intravenous bisphosphonates compared with a group of healthy children (n = 89). Within the study group, the correlation (Pearson correlation test) between the type of medication administered (pamidronate and/or zoledronic acid) and the chronology of tooth eruption is established, as well as the relationship between the amount of cumulative dose received and tooth eruption.

RESULTS

The age of eruption of the study group was significantly delayed compared to the age of eruption of the control group for molars and lateral incisors (p < 0.05). Patients who received higher cumulative doses had a delayed eruption age compared to those with lower cumulative doses (p < 0.05). There is a high positive correlation between age of delayed tooth eruption and Zoledronic acid administration.

CONCLUSION

Patients with OI have a delayed eruption of the 1st stage mixed dentition compared to a control group of healthy children. This delayed eruption is directly related to the cumulative dose of bisphosphonates and the administration of zoledronic ac.

Efficacy of the systemic co-administration of vitamin D3 in reversing the inhibitory effects of sodium alendronate on orthodontic tooth movement: A preliminary experimental animal study

INTRODUCTION

Bisphosphonates can severely slow down orthodontic tooth movement (OTM) by reducing bone turnover. This calls for materials and methods to reverse or neutralize their effects on OTM. We propose systemic vitamin D3 (D3) for this purpose.

METHODS

Thirty-two male Wistar rats were randomized into 4 groups of 8 each. Three groups were administered D3 (3 systemic doses of 24,000 IU/kg each), alendronate (ALN) (5 doses of 7 mg/kg each), and ALN+D3 (same doses as mentioned above). One group served as the negative control. The incisors were distalized at 30 g of force for 2 weeks. OTMs were measured blindly. Radicular pressure areas were searched histologically (blindly) for capillaries, Howship's lacunae, osteoclasts, and osteoblasts. Data were analyzed statistically (α = 0.05, α = 0.0083, β <0.1).

RESULTS

OTMs in the groups D3, ALN+D3, ALN, and control were 1.900 ± 0.237, 1.629 ± 0.219, 0.975 ± 0.145, and 1.565 ± 0.324 mm (analysis of variance, P <0.001), respectively. OTM in the ALN group was smaller than all other groups (Tukey, P <0.001). OTM in the D3 group was greater than in the control group (P = 0.054). The ALN+D3 group had greater OTM than the ALN group (P <0.001) but was not significantly different from the D3 (P = 0.153) or control (P = 0.951) groups. All histologic variables were significantly different across groups (Kruskal-Wallis, P <0.001). All the markers in the D3 group were more frequent than those of the other groups (Mann-Whitney U, P <0.001). There were fewer markers in the ALN group than in the control group (P ≤0.001). The ALN+D3 group had more markers than the ALN group in terms of capillaries, osteoclasts, and osteoblasts (P ≤0.007). The ALN+D3 group was similar to the control group regarding capillaries, osteoclasts, and osteoblasts (P ≥0.382).

CONCLUSIONS

Systemic vitamin D3 may accelerate OTM and increase histologic biomarkers of bone turnover. ALN reduces OTM and its histologic biomarkers. Systemic vitamin D3 can reverse this inhibitory effect of ALN on OTM back to normal.

The effect of high concentration of zoledronic acid on tooth induced movement and its repercussion on root, periodontal ligament and alveolar bone tissues in rats

Zoledronic acid (ZA) is often prescribed for osteoporosis or resorptive metabolic bone disease. This study aims to evaluate the effect of ZA on orthodontic tooth movement (OTM) and root and bone resorption and its repercussion on root, periodontal ligament and alveolar bone tissues. The experimental group consisted of 72 Wistar rats divided in four subgroups: Naive, Saline and Zoledronic Acid groups at the concentration of 0.2 mg/kg [ZA (0.2)] or 1.0 mg/kg [ZA (1.0)]. The animals were subjected to i.v (dorsal penile vein) administrations of ZA or saline solution, on days 0, 7, 14 and 42. Under anesthesia, NiTi springs were installed in the first left maxillary molar with 50gf allowing the OTM, except for the negative control group (N) for mesial movement of the left first maxillary teeth. The animals were sacrificed and maxillae were removed for macroscopic and histopathological analyzes, scanning electron microscopy, computerized microtomography and confocal microscopy. Treatment with ZA decreased the OTM and the number of osteoclasts and loss of alveolar bone when compared to the naive and saline groups. Reduction of radicular resorption, increased necrotic areas and reduced vascularization in the periodontal ligament were observed in the ZA groups. ZA interferes with OTM and presents anti-resorptive effects on bone and dental tissues associated with a decreased vascularization, without osteonecrosis.

Do various imaging modalities provide potential early detection and diagnosis of medication-related osteonecrosis of the jaw? A review

OBJECTIVE

Patients with medication-related osteonecrosis of the jaw (MRONJ) often visit their dentists at advanced stages and subsequently require treatments that greatly affect quality of life. Currently, no clear diagnostic criteria exist to assess MRONJ, and the definitive diagnosis solely relies on clinical bone exposure. This ambiguity leads to a diagnostic delay, complications, and unnecessary burden. This article aims to identify imaging modalities' usage and findings of MRONJ to provide possible approaches for early detection.

METHODS

Literature searches were conducted using PubMed, Web of Science, Scopus, and Cochrane Library to review all diagnostic imaging modalities for MRONJ.

RESULTS

Panoramic radiography offers a fundamental understanding of the lesions. Imaging findings were comparable between non-exposed and exposed MRONJ, showing osteolysis, osteosclerosis, and thickened lamina dura. Mandibular cortex index Class II could be a potential early MRONJ indicator. While three-dimensional modalities, CT and CBCT, were able to show more features unique to MRONJ such as a solid type periosteal reaction, buccal predominance of cortical perforation, and bone-within-bone appearance. MRI signal intensities of vital bones are hypointense on T₁WI and hyperintense on T₂WI and STIR when necrotic bone shows hypointensity on all T₁WI, T₂WI, and STIR. Functional imaging is the most sensitive method but is usually performed in metastasis detection rather than being a diagnostic tool for early MRONJ.

CONCLUSION

Currently, MRONJ-specific imaging features cannot be firmly established. However, the current data are valuable as it may lead to a more efficient diagnostic procedure along with a more suitable selection of imaging modalities.

The Dental Management of Patients at Risk of Medication-Related Osteonecrosis of the Jaw: New Paradigm of Primary Prevention

Medication-related osteonecrosis of the jaw (MRONJ) is a serious adverse reaction of antiresorptive and antiangiogenic agents; it is a potentially painful and debilitating condition that can considerably affect the quality of life of patients. Furthermore, even if its epidemiology and pathogenesis have still not been fully clarified, several risk factors related to MRONJ have been recognized in prevention protocols. Three main risk factors are as follows: (i) the type of ONJ-related medications: antiresorptive (e.g., Bisphosphonates, Denosumab) and antiangiogenic drugs (e.g., Bevacizumab, Sunitinib); (ii) the category of patient at MRONJ risk: cancer versus non-cancer patient; (iii) the typologies and timing of dental treatments (e.g., before, during, or after the drug administration). The aim of this paper is to describe the new paradigm by the Italian Society of Oral Pathology and Medicine (SIPMO) on preventive dental management in patients at risk of MRONJ, prior to and during/after the administration of the aforementioned ONJ-related drugs. In reducing the risk of MRONJ, dentists and oral hygienists are key figures in applying a correct protocol of primary prevention for pre-treatment and in-treatment patients. However, the necessity of a multidisciplinary standardized approach, with a sustained dialogue among specialists involved, should be always adopted in order to improve the efficacy of preventive strategies and to ameliorate the patient's quality of life.

Effect of local injection of Zolena, zoledronic acid made in Iran, on orthodontic tooth movement and root and bone resorption in rats

Background. Anchorage control is an essential part of orthodontic treatment planning, especially in adult patients who demand a more convenient treatment. Zoledronic acid (ZA) is an effective choice to address this problem. It is the most potent member of the bisphosphonates family that has an inhibitory effect on bone resorption by suppressing osteoclast function. Therefore, ZA might be a good option for orthodontic anchorage control. The current study evaluated the effect of local administration of Zolena (ZA made in Iran) on orthodontic tooth movement (OTM) and root and bone resorption. Methods. The experimental group consisted of 30 rats in 3 subgroups (n=10). Anesthesia was induced, and one closed NiTi coil spring was installed between the first molar and central incisor unilaterally, except for the negative control group. The positive control group received vestibular injection of 0.01 mL of saline next to the maxillary first molar, and 0.01 mL of the solution was injected at the same site in the ZA group. After 21 days, the rats were sacrificed and the distance between the first and second molars was measured with a leaf gauge. Histological analysis was conducted by a blind pathologist for the number of Howship's lacunae, blood vessels, osteoclast-like cells and root resorption lacunae. Data were analyzed with ANOVA, Tukey test and t-test. Results. There were no significant differences in OTM between the force-applied groups. ZA significantly inhibited bone/root resorption and angiogenesis compared to the positive control group. Conclusion. Zolena did not decrease OTM but significantly inhibited bone and root resorption. Zolena might be less potent than its foreign counterparts.

Effects of local alendronate administration on bone defect healing. Histomorphometric and radiological evaluation in a rabbit model

PURPOSE

To performed a histomorphometric and radiological study to evaluate the effects of alendronate sodium administered locally in mandibular bone defects created in rabbits.

METHODS

Two circular defects 5 mm in diameter were created bilaterally in the mandibular corpus of 20 New Zealand rabbits (i.e., four defects per animal). Each defect received one of four treatments: no treatment (EC group), alendronate irrigation (AL group), autogenous bone grafting (AG group), or alendronate irrigation with autogenous bone grafting (AL+AG group). Histomorphometric and radiological assessments were conducted at 4 and 8 weeks after surgery.

RESULTS

Between-group comparisons of the new bone area, the value of the AL+AG group was significantly lower thanthe remaining three groups at 4 weeks postoperatively. In all groups, the new bone area was significantly larger at 8 weeks than at 4 weeks. The residual graft area at 4 and 8 weeks was significantly higher in the AL+AG group than in the AG group, although it was significantly smaller at 8 weeks than at 4 weeks in both these groups.

CONCLUSION

The use of alendronate sodium in conjunction with autogenous bone grafting improves the osteoconductive properties of the graft, enhances graft retention in the defect, and improves ossification.

Applying orthodontic tooth extrusion in a patient treated with bisphosphonate and irradiation: a case report

Bisphosphonates and irradiation are useful medical treatments, but can often cause oral complications such as medication-related oral necrosis of the jaw (MRONJ) and osteoradionecrosis (ORN) during oral surgery, including tooth extraction. Therefore, we should take all risks into consideration carefully before choosing dental treatment for patients with a medical history of such therapies. A 55-year-old woman who underwent cord blood transplantation to treat extranodal natural killer T (NK/T) cell lymphoma (nasal type IVB) had a medical history of bisphosphonate and irradiation treatments. We treated her residual tooth root by applying orthodontic extrusion to avoid extraction and successfully restored the tooth. Application of an orthodontic tooth extrusion technique for conservative treatment of a residual tooth is a useful means of avoiding MRONJ or ORN in patients who have a medical history of bisphosphonate and irradiation treatments.

The effect of simvastatin on relapse of tooth movement and bone mineral density in rats measured by a new method using microtomography

PURPOSE

To evaluate the effect of simvastatin on relapse of tooth movement in rats using microtomography (micro CT), as well as the correlation of bone density with the orthodontic relapse.

METHODS

Twenty-five adult male Wistar rats, divided into two groups, had stainless steel springs installed on left maxillary first molar. The molars were moved for 18 days, and after removing the springs, were applied by oral gavage, 5mg/kg of simvastatin in the experimental group for 20 days. Tooth relapse was assessed with a micro CT scanner, and the images chosen through the Data Viewer software 1.5.0.0 had their measurement guides made and checked by the software Image ProR plus 5.1, and compared by Mann-Whitney test. After rats were sacrificed, bone mineral density was evaluated by micro CT through the software CT Analyzer 1.13 and compared by independent T-test, as well as by Spearman correlation test.

RESULTS

Relapse and bone mineral density (BMD) was lower in the experimental group than in the control group, however without a statistically significant difference.

CONCLUSION

Simvastatin did not inhibit the relapse of tooth movement in rats, and there was no correlation between bone density and orthodontic relapse.

Effect of bisphosphonates on orthodontic tooth movement-an update

Bisphosphonates are a synthetic class of pyrophosphate analogues that are powerful inhibitors of bone resorption which are commonly used as a medication for the prevention and therapy of osteoporosis and osteopenia, also used to treat tumor diseases. As it affects bone metabolism, it is said to have an influence on orthodontic treatment and tooth movement. Also, this review gives an insight into the reported effects of Bisphosphonate medication in literature highlighting the status quo of scientific research regarding effects of Bisphosphonates on orthodontic tooth movement. A systematic literature search was done in Medline database (Pubmed) for the appropriate keywords. Manual handsearch was also done. From the available evidence it can be concluded that the duration of orthodontic treatment is increased for patients under Bisphosphonate therapy as they interfere with the osteoclastic resorption. However, they may be beneficial for anchorage procedures. Further long term prospective randomized controlled trials are required to assess possible benefits and adverse effects of bisphosphonate treatment, before Bisphosphonates can be therapeutically used in orthodontics.

Effect of alendronate sodium on tooth movement in ovariectomized rats

OBJECTIVES

The aim of the present study was to evaluate the effect of two different dosages of alendronate on induced orthodontic movement in an experimental model involving rats with osteoporosis following ovariectomy.

DESIGN

Female Wistar rats (Rattus norvegicus) eight weeks of age were divided into four groups (n=12/group): ovariectomized (OVX group); ovariectomized and treated with alendronate sodium at 1mg/kg (Group OVX+ALN1); ovariectomized and treated with alendronate sodium at 2mg/kg (Group OVX+ALN2); and sham operated (control). Three months after ovariectomy, the maxillary right first molar was submitted to movement for five and seven days. After the death of the animals, the maxilla were removed and processed for microscopic evaluation. The maxillary left first molar (without movement) was used for comparison purposes in all groups. The samples were processed for the quantification of alveolar bone and tooth movement.

RESULTS

Intragroup comparisons showed significant movement after five and seven days (p<0.05) for all groups. Comparison among groups revealed greater tooth movement in the OVX group (p<0.05), on day 7.

CONCLUSIONS

Both alendronate sodium doses similarly decreased tooth movement in ovariectomized rats (p>0.05). Movement in ovariectomized+alendronate groups were also smaller than non-ovariectomized rats, however without statistical difference.

Administration of bisphosphonate (ibandronate) impedes molar tooth movement in rabbits: A radiographic assessment

Introduction:

Bisphosphonate (Bp)-ibandronate is a pharmacological agent, exhibits antiosteoclastic or antiresorptive activity and used to treat osteolytic or osteopenic disorders. BP-ibandronate may also interfere during orthodontic tooth movement. The aim of this study was to examine the influence of locally administered Bp-ibandronate on experimental tooth movement in rabbits.

Materials and Methods:

Twenty rabbits were divided into two groups- “10” served as Group-1 (control) and other “10” as Group-2 (experimental). Both groups received nickel-titanium closed coil springs with 100 g force between mandibular molar and incisors. Group-1 animals received 1 ml normal saline and Group-2 animals received ibandronate solution (0.3 mg/kg body weight) locally, mesial to the mandibular molar on the 1^st, 7^th, and 14^th day of the experiment. A total of “40” lateral cephalograms were taken from both groups on the 1^st and 21^st day using a digital X-ray unit (Siemens X-ray systems, 300 mA Pleomophos analog, 2008, Germany). Individually, each animal's radiograph was traced manually and superimposed. The molar tooth movement was measured with the help of a standard metric scale.

Results:

The Student's t-test has been done to compare the mean values of Group-1 (4.650 ± 0.363) and Group-2 (2.030 ± 0.291) and the difference was statistically significant (P < 0.001).

Conclusion:

The retarded molar tooth movement was noticed in local drug administered rabbits, which could be beneficial in orthodontics to control the undesired tooth movement.

The use of bisphosphonates in children: review of the literature and guidelines for dental management

Bisphosphonates are inhibitors of osteoclastic bone resorption with therapeutic benefit in a variety of bone disorders in both adults and children. While these agents have been routinely used in adults for the past three decades, their more recent introduction into paediatric medicine means there is a paucity of data on long-term safety and effects on dental development. There is uncertainty regarding the dental management of children treated with bisphosphonates, particularly when invasive dental procedures, such as extractions and oral surgical procedures, are required. There are limited data with which to make recommendations about the dental management of patients treated with bisphosphonates, and there are no published recommendations that specifically address paediatric patients. This paper aims to outline paediatric uses and adverse effects of bisphosphonates and present recommendations on the dental management of children receiving bisphosphonates.

[Orthodontic treatment of patients medicated with bisphosphonates-a clinical case report]

INTRODUCTION

Bisphosphonates (BP) are an established medication, e.g., for the prevention/therapy of osteoporosis. The effects of the changed bone metabolism for orthodontic treatments are unknown.

CASE REPORT

A 66-year-old woman underwent a total oral rehabilitation. The therapy included (1) tooth extractions, (2) periodontal treatment, (3) insertion of dental implants, (4) provisional implant restorations, (5) orthodontic treatment, and (6) definite implant restorations. The orthodontic tooth movements were in- and retrusion of the upper frontal teeth, intrusion of the lower front teeth, using the dental implants as skeletal anchorage. After implant insertion and one month before beginning the orthodontic treatment, osteoporosis was diagnosed in this patient and, without notification to our facility, BP treatment was initiated by her general practitioner (alendronate oral, 70 mg/week), with an overall duration of intake of 7 months. After 13 months, the orthodontic treatment was successfully accomplished; however enlarged periodontal gaps, sclerotic bone areas, and mild apical root resorptions of the upper frontal teeth were found in this patient.

CONCLUSION

Currently, there are no recommendations for orthodontic patients undergoing BP therapy. Orthodontic tooth movement in this low-risk patient with a short duration of intake and a low-dose BP medication was possible. Because of the reduced bone metabolism and the higher amount of side effects, the treatment should be performed with extremely light forces and frequent monitoring.

Factors related to the rate of orthodontically induced tooth movement

INTRODUCTION

The purpose of this study was to investigate the variations of orthodontically induced tooth movement in the maxillary and mandibular arches between patients and the factors such as age, sex, and presence of an interference that might influence the amount of tooth displacement.

METHODS

By using a standardized experimental orthodontic tooth movement in 30 subjects, 57 premolars were moved buccally during 8 weeks with the application of a 1-N force. Forty-four contralateral premolars not subjected to orthodontic tooth movement served as the controls. Plaster models from before and after the experimental tooth movement were digitized and superimposed to evaluate the amounts of tooth movement. Differences in tooth movement between the experimental and control groups were tested by an unpaired t test. For the experimental teeth, subject-related factors (age and sex) and tooth-related factors (location in the maxillary or mandibular dental arch, and the presence or absence of an intra-arch or interarch obstacle such as neighboring touching teeth or teeth interfering with the occlusion) were examined with analysis of variance. Multiple linear regression analysis was performed to determine correlations between tooth displacement, age, sex, tooth location, and presence of an interference.

RESULTS

Each subject contributed at least 2 experimental premolars and 1 control premolar. The displacement of the orthodontically moved teeth was 2.42 mm (range, 0.3-5.8 mm). Younger subjects (<16 years; n = 19; number of teeth, 36) had significantly greater amounts of tooth displacement compared with older subjects (≥16 years; n = 11; number of teeth, 21): 2.6 ± 1.3 mm vs 1.8 ± 0.8 mm; P <0.01. When an interarch or intra-arch obstacle was present, the amount of tooth movement was significantly less (2.6 ± 1.3 mm vs 1.8 ± 0.8 mm) (P <0.05). Neither sex nor the location of the experimental teeth in the mandible or the maxilla had any effect.

CONCLUSIONS

Younger patients showed greater tooth movement velocity than did older ones. An interarch or intra-arch obstacle decreased the amount of tooth displacement.

Current state of orthodontic patients under bisphosphonate therapy

Background

Bisphosphonates are a common medication for the prevention and therapy of osteoporosis, but are also applied for tumor diseases. They affect bone metabolism, and therefore also orthodontic treatments, but how it does has yet not been definitively clarified. Therefore, the aim of this research was to evaluate and demonstrate the reported effects and the current state of scientific research regarding orthodontic treatment and bisphosphonate medication exclusively in humans.

Material and methods

A systematic research of the literature for selected keywords in the Medline database (Pubmed) as well as a manual search was conducted. The following search terms were used: ‘Bisphosphonate’ in combination with: orthodontic, orthodontic treatment, tooth movement.

Findings

To date, only nine reported patients (case reports/series) and one original article (retrospective cohort study) regarding orthodontic treatment under bisphosphonate medication in humans have been published. Decelerated tooth movement with increased side effects (especially in high-risk patients) and longer treatment duration was reported in some articles. Patients with initial spacing or extraction cases had a higher risk of incomplete space closure and poor root parallelism.

Conclusions

Orthodontic tooth movement under bisphosphonate medication is possible, especially in low-risk patients (low dose and short period of intake). But the treatment is still not predictable, especially in high-risk patients. Therefore, the altered bone metabolism and higher extent of side effects should be considered in treatment planning, especially in extraction cases or high-risk patients. Regardless, longer treatment duration, decelerated tooth movement, and more side effects, e.g., incomplete space closure and poor root parallelism, should be expected, especially in extraction cases or space closure.

Effect of Reveromycin A on experimental tooth movement in OPG-/- mice

In osteoprotegerin-deficient (OPG-/-) mice, osteoclast activity causes bone resorption to outpace bone formation, leading to the development of severe osteoporosis. Such mice are therefore useful for investigating the alveolar bone of patients with osteoporosis. Reveromycin A (RM-A) was recently identified as the unique agent acting on osteoclast activation. This study aimed to analyze the effect of RM-A on the orthodontic treatment of OPG-/- mice (a model of osteoporosis patients with high levels of bone turnover). We examined alveolar bone remodeling in OPG-/- and wild-type (WT) mice during continuous tooth movement. The orthodontic force was induced by means of a Ni-Ti closed-coil spring to move the maxillary first molar for 14 days. RM-A sodium salt (1 mg/kg) was administered intraperitoneally twice daily. In OPG-/- mice, the tooth movement distance was longer, alveolar bone resorption was enhanced, the osteoclast count was greater, and serum alkaline phosphatase and tartrate-resistant acid phosphatase levels were higher relative to those in WT mice. However, the administration of RM-A in OPG-/- mice reduced these parameters. We conclude that RM-A normalizes bone metabolism and loss of alveolar bone during continuous tooth movement in OPG-/- mice.

[Optimizing orthodontic treatment in patients taking bisphosphonates]

Bisphosphonates have unique pharmacological characteristics unlike those of any other drug group. Millions of adults take oral bisphosphonates for long-term treatment of osteoporosis and osteopenia; some of these people will most likely also seek orthodontic treatment. Adverse dental effects from bisphosphonates have been reported, including decreased tooth movement, impaired bone healing, and osteonecrosis in the mandible and the maxilla. Osteonecrosis has been rarely observed after bisphosphonate use for osteoporosis. However, adverse drug effects might occur more frequently in orthodontic patients, and they would probably be noted before the end-stage pathology of osteonecrosis. Adverse effects during orthodontic treatment, including decreased tooth movement, could last for years after the drug therapy is stopped. Successful orthodontic treatment requires optimal bone healing to prevent excessive tooth mobility. Bisphosphonates appear to have two bone elimination rates - a fast elimination of weeks from the bone surface and a slow elimination of years after incorporation into the bone structure. This article presents methods to clinically and radiographically monitor orthodontic patients who are taking oral bisphosphonates. Efforts to minimize adverse effects and optimize orthodontic procedures with physician-approved drug holidays are discussed. The orthodontic treatment results of three patients who received bisphosphonate therapy are reported.

Effect of teriparatide on induced tooth displacement in ovariectomized rats: a histomorphometric analysis

INTRODUCTION

The aim of this study was to evaluate morphologically the effect of teriparatide on induced orthodontic movement of the maxillary first molars in ovariectomized rats.

METHODS

Ovariectomized Wistar rats (n = 16), ovariectomized rats treated with teriparatide (n = 16), and nonovariectomized rats (n = 16) had orthodontic tooth movement for 5 and 7 days. The group treated with teriparatide received a subcutaneous injection (Forteo, Eli Lilly, Indianapolis, Ind; 30 μg/kg/day) for 90 days after the ovariectomy. Histologic sections obtained from the maxilla were prepared for the morphometric analysis of dental movement, the thickness of the periodontal ligament, and the number of osteoclasts in the pressure and tension areas of the apex of the root and alveolar crest in the distal root of the maxillary first molars.

RESULTS

The ovariectomized rats treated with teriparatide had similar responses at 5 and 7 days after the induced dental movements compared with the untreated ovariectomized group. Both ovariectomized groups had greater molar movement on day 7 day compared with the controls (P <0.05). There were no statistically significant differences between groups in the spacing of the periodontal ligament or the number of osteoclasts in the areas studied.

CONCLUSIONS

These data suggest that the treatment of osteoporosis with teriparatide is a good alternative for patients undergoing orthodontic treatment.

Effects of clodronate on early alveolar bone remodeling and root resorption related to orthodontic forces: a histomorphometric analysis

INTRODUCTION

The objective of this study was to evaluate the short-term effects of clodronate, a first-generation bisphosphonate, on early alveolar bone remodeling and root resorption related to orthodontic tooth movement.

METHODS

The samples consisted of 54 sex-matched Wistar rats (weight, 180-230 g) allocated to the 2.5 mmol/L clodronate, 10 mmol/L clodronate, and control groups (n = 18 for each group). After application of a nickel-titanium closed-coil spring (force, 60 g) between the maxillary central incisor and first molar, 2.5 mmol/L of clodronate, 10 mmol/L of clodronate, or saline solution was injected into the subperiosteum adjacent to the maxillary first molar every third day. All animals received tetracycline, calcein, and alizarin red by intraperitoneal injection at 1, 6, and 14 days, respectively. The amounts of tooth movement were measured at 3, 6, 9, 12, and 15 days. The animals were killed at 4, 7, and 17 days. Histomorphometric analyses of bone mineral appositional rate, labeled surface, percentage of root resorption area, and number of root resorption lacunae of the mesiobuccal root of the maxillary first molar at 4, 7, and 17 days were done. One-way analysis of variance (ANOVA) with the post-hoc test were done for statistical analyses.

RESULTS

Rats in the 10 mmol/L clodronate group had significant decreases of tooth movement (12 and 15 days, P <0.05) and percentages of root resorption area and numbers of root resorption lacunae (7 day, P <0.05), and increases of labeled surface and mineral appositional rates (17 day, P <0.05) over those of the 2.5 mmol/L clodronate and control groups.

CONCLUSIONS

Although clodronate might decrease root resorption related to orthodontic tooth movement, patients should be informed about a possible decrease in the amount of tooth movement and a prolonged period of orthodontic treatment.

Bisphosphonate-Related Osteonecrosis of the Jaw Bone: Radiological Pattern and the Potential Role of CBCT in Early Diagnosis

Objectives

To systematize the clinico-radiological symptoms and course of bisphosphonate-related osteonecrosis of jaw bone and toevaluate the diagnostic potential of various radiological techniques to detect mild osteonecrosis in each stage of the disease.

Material and Methods

The sample consisted of 22 patients previously diagnosed with extraoral malignant disease. Diagnosis was based on a clinical examination in conjunction to digital panoramic radiography and cone beam computed tomography (CBCT). Two dentomaxillofacial radiologists reviewed all images.

Results

Twenty patients showed mandibular involvement clinically, while two others had a maxillary involvement. Four stages of the disease were proposed based on the clinico-radiological findings. Subclinical cortical and lamina dura thickening was detected with only three-dimensional CBCT and periapical images, while ulceration and cortical bone thickening was detected only by three-dimensional CBCT. Mixed sclerotic, lytic bone destruction involving alveolar and basal bone with or without encroachment on the mandibular canal, pathological mandibular fractures were detected by two-dimensional panoramic and three-dimensional CBCT images. Other findings are non healing extraction sockets, periapical radiolucencies, osteolysis, sequestra, oroantral fistula, and periosteal new bone formation.

Conclusions

The present study showed that bisphosphonate-related osteonecrosis of jaw bone occurs in four distinct clinico-radiological stages. For mild cases, panoramic image diagnosis was much less obvious, whereas cone beam computed tomography was able to fully characterise the bony lesions and describe their extent and involvement of neighbouring structures in all cases. Thus cone beam computed tomography might better contribute to the prevention of bisphosphonate-related osteonecrosis of jaw bone as well to the disease management.

Tooth movement - clinical implications

The tissue-based phenomena and the tissue interactions responsible for tooth displacement can be modulated by varying the intensity of the applied forces or by means of medicated molecules absorbed by the patient or prescribed by the orthodontist. However, harmful side-effects such as inflammatory root resorption or replacement resorption (ankylosis) can occur requiring appropriate management on the part of the practitioner.

Modulation of murine bone marrow-derived CFU-F and CFU-OB by in vivo bisphosphonate and fluoride treatments

OBJECTIVES

Bisphosphonates (BPN) have actions on a variety of cell types including: osteoclasts, osteoblasts, osteocytes, and endothelial cells. The objectives of this report are to review the current state of understanding of the effects of BPNs on orthodontic tooth movement and to provide evidence on BPN's in vivo effects on bone marrow-derived osteoprogenitor cells.

MATERIAL AND METHODS

Mice from the C3H/HeJ (C3H), C57BL/6J (B6), FVB/NJ (FVB), and BALB/cByJ (BALB) strains were treated for 3 weeks with 0, 3, 30, or 150 mcg/kg/week alendronate (ALN) administered subcutaneous alone or in combination with 50 ppm fluoride (F). Bone marrow cells were harvested and subjected to in vitro colony-forming unit fibroblast (CFU-F) and colony-forming unit osteoblasts (CFU-OB) assays.

RESULTS

Baseline differences in CFU-F, CFU-OB/ALP+, and CFU-OB/total were observed among the four strains. Strain-specific responses to ALN and F treatments were observed for CFU-F, CFU-OB/ALP+, and CFU-OB/total. F treatment alone resulted in decreases in CFU-F (p = 0.013), CFU-OB/ALP+ (p = 0.005), and CFU-OB/total (p = 0.003) in the C3H strain. CFU-F (p = 0.036) were decreased by F in the B6 strain. No significant (NS) effects of F were observed for FVB and BALB. ALN treatment resulted in a significant decrease in CFU-F (p = 0.0014) and CFU-OB/total (p = 0.028) in C3H only. ALN treatment had NS effect on CFU-OB/ALP+ in all four strains.

CONCLUSION

Genetic factors appear to play a role in ALN's effects on CFU-F and CFU-OB/total but not on CFU-OB/ALP+.

Dental management of patients at risk of osteochemonecrosis of the jaws: a critical review

Osteonecrosis of the jaw bones is a complication of bisphosphonate (BP) drug usage characterised by trans-mucosal exposure of necrotic bone, often followed by infection and pain. Osteonecrosis is observed in cancer patients on high-potency intravenous BP more frequently than in osteoporotic individuals using low-potency oral BP. The management of osteonecrosis caused by BP is often unsatisfactory and control of risk factors is considered the most effective means of prevention. Surgical manipulation and dental infection of the jawbone are the major risk factors, hence it is suggested that careful management of oral health and relevant dental procedures may decrease the risk of osteonecrosis in individuals on BP. Recommendations for dentists and oral surgeons have been suggested by different groups of clinicians but they are often controversial and there is no clear evidence for their efficacy in reducing the likelihood of osteonecrosis development. This report critically reviews current dental recommendations for individuals using BP with the aim of helping the reader to transfer them into practice as part of pragmatic and non-detrimental clinical decisions making.

Medication effects on the rate of orthodontic tooth movement: a systematic literature review

INTRODUCTION

Recently, several reviews have been published on the effects of medications on bone physiology and the clinical side effects in orthodontics. However, the effects of medications on the rate of orthodontic tooth movement have not been evaluated.

METHODS

A systematic literature review on the effects of medications and dietary supplements on the rate of experimental tooth movement was performed by using PubMed (1953-Oct 2007), Web of Science, and Biosis, complemented by a hand search.

RESULTS

Forty-nine articles were included in the review, but their interpretation was hindered by the variability in experimental design, magnitude of force applied during tooth movement, and medication regimens. Therapeutic administration of eicosanoids resulted in increased tooth movement, whereas their blocking led to a decrease. Nonsteroidal anti-inflammatory drugs (NSAIDs) decreased tooth movement, but non-NSAID analgesics, such as paracetamol (acetaminophen), had no effect. Corticosteroid hormones, parathyroid hormone, and thyroxin have all been shown to increase tooth movement. Estrogens probably reduce tooth movement, although no direct evidence is available. Vitamin D3 stimulates tooth movement, and dietary calcium seemed to reduce it. Bisphosphonates had a strong inhibitory effect.

CONCLUSIONS

Medications might have an important influence on the rate of tooth movement, and information on their consumption is essential to adequately discuss treatment planning with patients.