Inter-premaxillary Suture Research Articles

Effect of Adeno-Associated Virus-Transfected Mesenchymal Stem Cells Containing Agents On Bone Formation in Extended İnter-Premaxillary Suture in Rats

Aim: The aim of this study was to investigate the histomorphometric effects of bone marrow-derived mesenchymal stem cells (MSCs) transfected with Adeno Associated Virus (AAV) and containing bone morphogenic protein 7 (Bmp7) or osteoprotegerin (OPG) on bone formation after injection into inter-premaxillary suture in rats with Bmp7 or OPG alone. Materials and methods: In 4 groups (each group n:9), different chemical solutions, namely AAV-Bmp7, AAV-OPG and AAV-Bmp7-OPG and AAV-EGF (control group) were injected into the interpremaxillary suture of rats. Bone volumes (BV), soft tissue volume (STV) and total bone volumes (TBV) of 10 μm serial selection with hemotoxylin and eosin staining were calculated according to the Cavalieri principle. Each point in the region of interest was 1000μm3. Results: The BV for AAV-Bmp7, AAV-OPG, AAV-Bmp7-OPG and AAV-EGF were 46.98±1.50 mm3, 49.40±4.72 mm3, 42.58±2.89 mm3 and 38.82±0.76 mm3, respectively. The STV was 11.53±0.99, 13.31±1.88, 8.00±4.43 and 9.57±1.90 mm3 for Bmp7, OPG, AAV-Bmp7-OPG and AAV-EGF, respectively. TBV was 58.34±2.28 mm3, 63.83±5.17 mm3, 53.74±3.34 mm3 and 48.13±1.54 mm3 for AAV-Bmp7, AAV-OPG, AAV-Bmp7-OPG and AAV-EGF, respectively. The comparison between BV, STV, TBV for AAV-OPG showed a statistically significant difference (p=0.001) compared to AAV-Bmp7 or AAV-Bmp7-OPG and AAV-EGF. Conclusion: During tooth movement and bone remodeling, the ratio of soft and bone tissues is maintained by OPG. Although Bmp7 is not as effective as OPG in bone remodeling, both can reduce the retention time and the risk of recurrence.

Effect of Grape Seed Extract on Bone Formation in The Expanded Inter-premaxillary Suture

Effect of Grape Seed Extract on Bone Formation in The Expanded Inter-premaxillary Suture

Effect of Energy Drink on Bone Formation in the Expanded Inter-Premaxillary Suture.

Maxillary expansion of the median palatal suture is a common procedure in orthodontics. Even after retention, there is a strong tendency to relapse in the expanded suture. The authors' objectives are to accelerate the bone formation process in the expanded suture and to reduce the required retention time by using an energy drink (ED). Twenty rats were divided into 2 groups (n = 20). The expansion-only group was defined as the control group (Group C). The other group was defined as the expansion-plus-energy drink group (Group ED). In Group ED, ED was administered systemically through oro-gastric tubes after the expansion period. After 5 days of expansion, the springs were removed and replaced with short lengths of rectangular retaining wire. Tooth separation was maintained for 12 days. Histomorphometric analysis showed significant differences between the 2 groups in terms of newly formed bone (P = 0.018) and the bone area (P = 0.007). For the parameters that were investigated, Group ED had better results than Group C. These results show that systemic administration of an ED during the early stages of the orthopedic expansion of the inter-maxillary suture areas can stimulate bone formation and decrease the time required for retention.

Does stinging nettle (Urtica dioica) have an effect on bone formation in the expanded inter-premaxillary suture?

ObjectiveTo determine whether systemically given stinging nettle (SN) has an effect on bone formation in response to expansion of the rat inter-premaxillary suture. Materials and methodsA total of 28 male Wistar albino rats were randomly divided into 4 equal groups: control (C), only expansion (OE), SN extract given only during the expansion and retention periods (SN group; a total of 17days), and SN extract given during the nursery phase before expansion (a period of 40days) and during the expansion and retention periods (N+SN group; a total of 57days). After the 5-day expansion period was completed, the rats in the OE, SN, and N+SN groups underwent 12days of mechanical retention, after which they were sacrificed, and their premaxilla were dissected and fixed. A histologic evaluation was done to determine the number of osteoblasts, osteoclasts, and capillaries, as well as the number and intensity of inflammatory cells and new bone formation. ResultsStatistically significant differences were found between the groups in all histologic parameters except the ratio of intensities of inflammatory cells. New bone formation and the number of capillaries were significantly higher in the SN groups than in the other groups. The statistical analysis also showed that the numbers of osteoblasts, osteoclasts, and capillaries were highest in the N+SN group. ConclusionSystemic administration of SN may be effective in accelerating new bone formation and reducing inflammation in the maxillary expansion procedure. It may also be beneficial in preventing relapse after the expansion procedure.

Effect of hyaluronic acid on bone formation in the expanded interpremaxillary suture in rats.

To evaluate the histomorphometric effects of different molecular weight hyaluronic acid on bone formation in rats after expansion of the interpremaxillary suture. Twenty-four male Sprague Dawley rats were divided into three groups. Each group was subjected to expansion for 5 days and retention for 10 days. Group 1 received 50 μl of high molecular weight hyaluronic acid (HMWHA), group 2 received 50 μl of low molecular weight hyaluronic acid (LMWHA), and the control group received same amount of saline solution to the interpremaxillary suture. Ten days after injection, the rats were killed and their maxillas dissected. For the histomorphometric evaluation, blocks were serially sectioned at 10-μm intervals. Sections were stained with hematoxylin-eosin (HE) and evaluated with image analysis software. Bone area (μm²) (BA), bone perimeter of suture borders (μm) (BP), and ratio of osteoblast cells and capillary cells to BA and BP parameters were evaluated. HMWHA showed a statistically higher ratio of osteoblast and capillary cell scores compared with the LMWHA and control groups (p < 0.05). There were no statistically significant differences in between LMWHA and control groups (p > 0.05). Local injection of HMWHA in the interpremaxillary suture after rapid maxillary expansion stimulated new bone formation, which may shorten the retention period and may reduce the risk of relapse. LMWHA has no effect on bone formation in interpremaxillary suture.

Effect of caffeic acid phenethyl ester on bone formation in the expanded inter-premaxillary suture.

BackgroundNarrow maxilla is a common problem in orthodontics and dentofacial orthopedics. To solve this problem, a procedure called rapid maxillary expansion (RME) has been used. However, relapse tendency is a major problem of RME. Although relapse tendency is not clearly understood, various treatment procedures and new applications have been investigated. The present study aimed to investigate the possible effectiveness of caffeic acid phenethyl ester (CAPE) on new bone formation in rat midpalatal suture after RME.Materials and methodsTwenty male Sprague Dawley rats were used in this study. The animals were randomly divided into two groups as control and CAPE group. In the CAPE group, CAPE was administered systemically via intraperitoneal injection. RME procedure was performed on all animals. For this purpose, the springs were placed on the maxillary incisors of rats and activated for 5 days. After then, the springs were removed and replaced with short lengths of rectangular retaining wire for consolidation period of 15 days. At the end of the study, histomorphometric analysis was carried out to assess new bone formation.ResultsNew bone formation was significantly greater in the CAPE group than the control group (P<0.05). CAPE enhances new bone formation in midpalatal suture after RME.ConclusionThese results show that CAPE may decrease the time needed for retention.

The effect of different concentrations of topical ozone administration on bone formation in orthopedically expanded suture in rats.

The aim of this study was to investigate the effects of different concentrations of ozone (O3) therapy on bone regeneration in response to an expansion of the inter-premaxillary suture in rats. Forty-eight Wistar rats were randomly divided into four groups (n = 12). In groups I, II, and III, 1ml of O3 at 10, 25, and 40 µg/ml was injected at the premaxillary suture, respectively. In group IV (control group), 1ml of saline solution was injected at the same point during the expansion procedure for 5 days. Bone regeneration in the suture was evaluated histomorphometrically. The area of new bone and fibrotic area, the number of osteoblasts and osteoclasts, and the amount of vascularity were measured and compared. The density of the newly formed bone in the expansion area was measured by using cone beam computed tomography. Data were analyzed using the Kruskal-Wallis one-way analysis of variance and post hoc Student-Newman-Keuls tests. New bone area, fibrotic area, osteoblast and osteoclast numbers, and the amount of vascularity were significantly higher in experimental groups compared with the control group (P < 0.001). The density of newly formed bone (P < 0.001), new bone formation (P = 0.009), number of capillaries (P < 0.001), number of osteoclasts (P = 0.016), and number of osteoblasts (P < 0.001) in the maxillary sutures were highest in the 25 μg/ml O3 group compared with the other experimental groups and control group. The application of O3 therapy can stimulate bone regeneration in an orthopedically expanded inter-premaxillary suture during both the expansion and retention periods.

Effects of low-intensity pulsed ultrasound on bone formation after the expansion of the inter-premaxillary suture in rats: a histologic and immunohistochemical study

Abstract Background: Orthodontic maxillary expansion is a commonly-performed treatment approach to correct transverse maxillary deficiencies by separating the mid-palatal suture. To obtain a successful treatment result and prevent relapse, the expanded maxillary sutures require maintenance by means of qualified bone reorganisation. Aim: To assess the effects of low-intensity pulsed ultrasound (LIPUS) on sutural bone formation after the expansion of the inter-premaxillary suture in rats. Methods: Sixteen male Wistar rats, 6 to 8-week old, were used. The expansion appliance comprised a helical spring fabricated from 0.014 inch stainless steel wire (Dentaurum, Ispringen, Germany). The rats were divided into two equal groups and randomly assigned to the LIPUS treatment group or a sham-operation group. LIPUS was delivered via a 2.5 cm diameter ultrasound transducer (Exogen, Smith and Nephews, Inc., Memphis, TN, USA) for 20 minutes per day during 7 days of post-expansion retention. Following retention, the rats’ maxillae were surgically removed and histologic and immunohistochemical specimens were prepared and examined. Results: The number of osteoblasts and blood vessel dimensions in the ultrasound group increased but was not significant, compared with the control group. A statistically significant difference in osteocalcin, VEGF and TGF-β immunoreactivities (p &lt; 0.01) was found in the area of the mineralising tissue. Only VEGF immunoreactivity was significant between two groups (p &lt; 0.01) in the fibrous tissue area. Conclusions: The area of mineralising tissue in the LIPUS-applied group expressed activity markers for osteocalcin, VEGF and TGF-β compared with a surrounding area of fibrous tissue. Cellular activation in the LIPUS group was greater than that of controls. Therefore, LIPUS may be accepted as a useful approach to enhance sutural bone formation.

Bone marrow mesenchymal stem cells enhance bone formation in orthodontically expanded maxillae in rats.

To transplant bone marrow-derived mesenchymal stem cells (MSCs) into the interpremaxillary suture after rapid maxillary expansion with the aim of increasing new bone formation in the suture. Nineteen male Wistar rats were divided into two groups (control, n = 9; experimental, n = 10). Both groups were subjected to expansion for 5 days, and 50 cN of force was applied to the maxillary incisors with a helical spring. Pkh67(+) (green fluorescent dye)-labeled MSCs were applied to the interpremaxillary suture after force application into the interpremaxillary suture of rats. Bone formation in the sutural area was histomorphometrically evaluated, including the amount of new bone formation (µm(2)), number of osteoblasts, number of osteoclasts, and number of vessels. Mann-Whitney U-test was used for statistical evaluation at the P < .05 level. After 10 days of retention, Pkh67(+) can be detected in suture mostly in the injection site under fluorescence microscope. Histomorphometric analysis revealed that a single local injection of MSCs into the midpalatal suture increased the new bone formation in the suture by increasing the number of osteoblasts and new vessel formation, compared with controls injected with phosphate-buffered saline. This preclinical study might provide foundations for the underlying potential clinical use of MSCs after maxillary expansion. Given the fact that MSCs are currently in use in clinical trials, this approach might be a feasible treatment strategy to accelerate new bone tissue formation in midpalatal suture and to shorten the treatment period for patients undergoing maxillary expansion reinforcement.

Analysis of the calcification caused by rapid expansion of interpremaxillary suture in growing rats

Changes in the bone mineral density and the speed of mineralization were evaluated when the interpremaxillary suture received a physiological or orthodontic force in rats' growth period. Wistar rats (N = 30), 6 weeks of age at the beginning of the experiment, were used for this study. A rapid expansion appliance was set on the maxillary incisors of the rats in the experimental groups (1.5 mm expansion and 2.0 mm expansion groups), while the same appliance without activation was placed in the control group animals. The three groups were additionally divided into the following subgroups (five rats in each subgroup): the fed for 10 days subgroup and the fed for 24 days subgroup.Evaluation of bone mineral density by peripheral quantitative computed tomography (pQCT) in rats' transverse and frontal sections which include the interpremaxillary suture showed that bone mineral density in the 1.5 mm expansion group and in the 2.0 mm expansion group did not recover to the level in the control group. Bone formation seemed to be accelerated in the 2.0 mm expansion group among the rats fed for 24 days, though bone mineral density did not recover to the level in the control group. These results suggest that it is essential to observe retrace and bone formation enough after expansion.However, in the observation using calcein staining, the speed of calcification in the interpremaxillary suture in the 2.0 mm expansion group was more rapid than in the control and the 1.5 mm expansion groups, which indicated the effectiveness of rapid expansion in puberty.

Caiman gasparinae sp. nov., a huge alligatorid (Caimaninae) from the late Miocene of Paraná, Argentina

Bona, P. & Paulina Carabajal, A., 2013. Caiman gasparinae sp. nov., a huge alligatorid (Caimaninae) from the late Miocene of Paraná, Argentina. Alcheringa 37, 1–12. ISSN 0311-5518Morphological studies of South American alligatorids are scarce, and the phylogenetic relationships within Caimaninae are poorly understood. In this context, systematic revision and detailed morphological description of the enigmatic Argentinean Miocene caimanines are highly relevant. The current record is characterized by numerous species within the genus Caiman, although morphological disparity remains unclear. Here, we describe Caiman gasparinae sp. nov., which is one of the largest known Caiman species from the late Miocene of Argentina. Similar to other Caiman species and Melanosuchus, the new taxon has orbits larger than the infratemporal fenestrae and small supratemporal fenestrae that are not lost, as in Paleosuchus. Together with the absence of conspicuous rostral crests, the shape of the snout distinguishes C. gasparinae from Melanosuchus. Caiman gasparinae can be further distinguished using other cranial characters, such as a broad and low rostrum with a narial opening oriented dorsally, a relatively long interpremaxillary suture, and the occipital surface of the braincase with a poorly developed crista tuberalis exposing the carotid foramina in lateral view.Paula Bona [paulabona26@gmail.com] CONICET—División Paleontología Vertebrados, Museo de La Plata. Paseo del Bosque s/n, 1900, La Plata, Argentina; Ariana Paulina Carabajal [a.paulinacarabajal@conicet.gov.ar] CONICET—Museo Carmen Funes. Av. Córdoba 55 (8318), Plaza Huincul, Neuquén, Argentina. Received 21.8.2012; revised 29.1.2013; accepted 9.3.2013.

The effect of isoflavones on early bone formation on orthopedically expanded suture in male rats

Objective: The aim of this experimental study was to evaluate histomorphometrically the effects of isoflavones on bone formation in response to expansion of the inter-premaxillary suture in male rats. Materials and Methods: Twenty male, 50-60 days old Wistar rats were divided into two equal groups (control and experimental). Both groups were subjected to expansion for 5 days, and 50 cN of force was applied to the maxillary incisors with helical spring. In experimental group, 10 μg/g isoflavones (IF) were administrated orally. After expansion period, the springs were removed and replaced with short lengths of rectangular retaining wire for retention period in 10 days. Bone formation in the sutural area was histomorphometrically evaluated including the amount of new bone formation (μm 2 ), number of osteoblasts, number of osteoclasts, and number of vessels. Mann-Whitney U -test was used for statistical evaluation at P Results: New bone formation area ( P = 0.003; 2.26-fold) and number of osteoclasts ( P = 0.001; 1.87-fold) showed statistically significant lower values in experimental group than the control. No significant differences were found in number of osteoblast and number of vessel values between the groups. Conclusion: Isoflavones affects bone formation in the orthopedically expanded inter-premaxillary suture negatively, and main affect of Isoflavones were on osteoclasts in bone metabolism.

From shape to cells: mouse models reveal mechanisms altering palate development in Apert syndrome

SUMMARYApert syndrome is a congenital disorder characterized by severe skull malformations and caused by one of two missense mutations, S252W and P253R, on fibroblast growth factor receptor 2 (FGFR2). The molecular bases underlying differential Apert syndrome phenotypes are still poorly understood and it is unclear why cleft palate is more frequent in patients carrying the S252W mutation. Taking advantage of Apert syndrome mouse models, we performed a novel combination of morphometric, histological and immunohistochemical analyses to precisely quantify distinct palatal phenotypes in Fgfr2+/S252W and Fgfr2+/P253R mice. We localized regions of differentially altered FGF signaling and assessed local cell patterns to establish a baseline for understanding the differential effects of these two Fgfr2 mutations. Palatal suture scoring and comparative 3D shape analysis from high resolution μCT images of 120 newborn mouse skulls showed that Fgfr2+/S252W mice display relatively more severe palate dysmorphologies, with contracted and more separated palatal shelves, a greater tendency to fuse the maxillary-palatine sutures and aberrant development of the inter-premaxillary suture. These palatal defects are associated with suture-specific patterns of abnormal cellular proliferation, differentiation and apoptosis. The posterior region of the developing palate emerges as a potential target for therapeutic strategies in clinical management of cleft palate in Apert syndrome patients.

Bone Marrow Mesenchymal Stem Cells Enhances Bone Formation in Orthopedically Expanded Interpremaxillary Suture in Rats

Bone Marrow Mesenchymal Stem Cells Enhances Bone Formation in Orthopedically Expanded Interpremaxillary Suture in Rats

Light-emitting diode photobiomodulation: effect on bone formation in orthopedically expanded suture in rats—early bone changes

The aim of this experimental study was to evaluate histomorphometrically the effects of light-emitting diode (LED) photobiomodulation therapy (LPT) on bone formation in response to expansion of the interpremaxillary suture in rats. Twenty male, 50- to 60-day-old Wistar rats were divided into two equal groups (control and experimental). Both groups were subjected to expansion for 5days, and 50cN of force was applied to the maxillary incisors with helical spring. An OsseoPulse® LED device, 618-nm wavelength and 20-mW/cm(2) output power irradiation, was applied to the interpremaxillary suture for 10days. Bone formation in the sutural area was histomorphometrically evaluated, including the amount of new bone formation (in square micrometers), number of osteoblasts, number of osteoclasts, and number of vessels. Mann-Whitney U test was used for statistical evaluation at p < 0.025 level. Significant differences were found between groups for all investigated histomorphometric parameters. New bone formation area (p = 0.024, 1.48-fold), number of osteoblasts (p < 0.001, 1.59-fold), number of osteoclasts (p = 0.004, 1.43-fold), and number of vessels (p = 0.007, 1.67-fold) showed higher values in the experimental group than the control. Bone histomorphometric measurements revealed that bone architecture in the LPT group was improved. The application of LPT can stimulate bone formation in the orthopedically expanded interpremaxillary suture during expansion and the early phase of the retention periods.

Effect of vitamin C on bone formation in the expanded inter-premaxillary suture. Early bone changes

The aim of this experimental study was to histomorphometrically evaluate the effects of vitaminC administration on bone formation in response to expansion of the rat inter-premaxillary suture. A total of 30 50- to 60-day old Wistar male rats were divided into three groups of equal number. The inter-premaxillary suture in each animal was expanded with a 0.49N force applied to the upper incisors. At 24h after appliance placement, control animals received saline solution (groupI) and two groups were given a single dose of vitaminC using two different methods [locally into the suture (groupII) and systemically via intramuscular injection (groupIII)]. The area of new bone (µm(2)), the perimeter around the new bone (µm), Feret's diameter (µm), and the percentage of new bone to non-ossified tissue (%) were measured and compared. Kruskal-Wallis and Tukey tests were used for statistical evaluation at the p<0.05 level. We observed significant differences among the groups in all histomorphometric parameters. New bone area, bone perimeter, Feret's diameter, and percentage of new bone dimensions were significantly higher in groupIII than the others (p<0.001). Histomorphometric measurements of bone architecture revealed that this improved in the group administered with vitaminC systemically, while local injection revealed significantly less bone growth than the control group. The systemic administration of vitaminC during the early stages of inter-premaxillary suture expansion may stimulate bone growth. However, local injection of this antioxidant into an orthopedically-expanded suture area has negative effects on bone formation.

Effect of resveratrol on bone formation in the expanded inter‐premaxillary suture: early bone changes

The aim of this study was to evaluate the effects of local resveratrol (RSVL) administration on bone formation in response to expansion of the inter-premaxillary suture, in rats. Twenty 50- to 60-day-old male Wistar rats were separated into two equal groups. Both groups were subjected to expansion, and 30 cN of force was applied to the maxillary incisors with helical-spring. Twenty-four hours after appliance placement, single-dose 10 μmol/kg RSVL in the dimethylsulfoxide (DMSO) was injected to the inter-premaxillary suture in the experimental group. In the control group, the same amount of DMSO was injected to the suture of rats. Bone formation in the suture was evaluated histomorphometrically. The area of new bone (μm(2)), the perimeter around the new bone (μm), Feret's diameter (μm), the percentage of new bone to non-ossified tissue (%), and the number of osteoblast were measured and compared. Mann-Whitney U-test was used for statistical evaluation at p < 0.05 level. Statistically significant differences were found between the groups for all histomorphometric parameters. New bone area (p < 0.001), bone perimeter (p < 0.001), Feret's diameter (p < 0.001), percentage of new bone (p < 0.001), and the number of osteoblast (p < 0.001) were significantly larger in the experimental group when compared with the control. Bone histomorphometric measurements revealed that bone architecture in the RSVL treated rats was improved. Local application of RSVL during the early stages to orthopedically expanded inter-premaxillary suture area may stimulate bone formation and shorten the retention period, in rats.

Response of the expanded inter-premaxillary suture to intermittent compression. Early bone changes

Abstract Objective To determine the response of the expanded premaxillary suture in the rat to an externally applied force. Specifically, to investigate early bone changes in the expanded suture to intermittent loading and unloading. Methods Twenty-four 50 to 60 day-old Wistar rats were assigned to three groups. The inter-premaxillary sutures in all animals were expanded with a 50 g force applied to the upper incisors. Group I served as the control, whereas in Groups II and III the incisors were subjected to intermittent loading and unloading after five days of expansion. The intermittent forces were produced by a cam (0.416 mm, 100 cycles per minute) applied to the disto-gingival margins of the upper incisors. The mechanical stimuli were applied daily over nine days for six seconds in Group II (30 grams force, 10 cycles/day) and 10 minutes in Group III (30 grams force, 1000 cycles/day). Bone regeneration in the suture was evaluated histomorpho-metrically. The area of new bone (μm2), the perimeter around the new bone (μm), Feret’s diameter (μm) and the percentage of new bone to non-ossified tissue (%) were measured and compared. Results Statistically significant differences were found between the groups for all histomorphometric parameters. New bone area (p &lt; 0.001), bone perimeter (p &lt; 0.001), Feret’s diameter (p &lt; 0.001) and percentage of new bone (p &lt; 0.001) were significantly larger in the experimental groups as compared with the Control group. The histomorphometric measurements confirmed that more new bone was deposited in the sutures subjected to intermittent loading and unloading. Conclusion The application of cyclic loading and unloading to the orthopaedically expanded inter-premaxillary suture during the early retention phase stimulated the formation of new bone.

Effect of periosteal stimulation therapy on bone formation in orthopedically expanded suture in rats

The aim of this experimental study was to evaluate the effects of periosteal stimulation therapy (PST), on bone regeneration in response to expansion of the interpremaxillary suture, in rats. Sixteen male, 50-60 days old Wistar rats were divided into two equal groups (control and experimental). Both groups were subjected to expansion for 5 days, and 30 cN of force was applied to the maxillary incisors with helical spring. On the 2nd day of the expansion procedure in the experimental group, the periosteum over the interpremaxillary suture was stimulated locally by intraperiosteal penetrations with a hypodermic needle. Bone regeneration in the interpremaxillary suture was evaluated by bone histomorphometry and the new bone area, bone perimeter, feret's diameter and new bone/old bone percentage parameters were evaluated. Mann-Whitney U-test was used for statistical evaluation at p < 0.05 level. Significant differences were found between groups for all investigated histomorphometric parameters. New bone area (p < 0.01), bone perimeter (p < 0.05), feret's diameter (p < 0.01) and new bone/old bone percentage (p < 0.01) measurements were significantly higher in the experimental group than that in the control. Bone histomorphometric measurements revealed that bone architecture in the PST group was improved. Local stimulation of the periosteum of the sutural area during expansion stimulates bone formation and improves healing.

Stimulation of bone formation by direct electrical current in an orthopedically expanded suture in the rat

Objective: The aim of this experimental study was to evaluate the effects of direct electrical current stimulation (DECS) on bone regeneration in response to an expansion of the inter-premaxillary suture in the rat. Methods: Sixteen 50 - 60 days old Wistar male rats were separated into two equal groups (control and experimental). Both groups were subjected to expansion, and 30-gram of force was applied to the maxillary incisors with helical-spring. In the experimental group, two metallic-screws were placed at lateral parts of the maxillary segments. Electrodes were connected to the screws. The device was activated with current adjustment to measure 10μA continuously and the current was monitored daily during the expansion and early-retention phase. Bone regeneration in the sutural area was histomorphometrically evaluated including new-bone area (μm 2 ), bone perimeter (μm), feret’s diameter (μm) and newly formed bone (%) parameters. Kruskal-Wallis rank and Mann-Whitney U tests were used for statistical evaluation at p ＜ 0.05 level. Results: Statistical analysis showed significant differences between groups for all investigated histomorphometric parameters. New bone area (p = 0.002), bone perimeter (p = 0.004), feret’s diameter (p = 0.002) and newly formed bone percentage (p = 0.002) measurements were significantly higher in the experimental group than the control group. Bone histomorphometric measurements revealed that bone architecture in the DECS group was improved. Conclusions: The application of DECS to an orthopedically expanded inter-premaxillary suture area during the early retention phase stimulated the formation of new bone. (Korean J Orthod 2010;40(2):106-114)