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PubMed2005

The effect of irradiation and hyperbaric oxygenation (HBO) on extracellular matrix of the condylar cartilage after mandibular distraction osteogenesis in the rabbit.

The effects of irradiation and hyperbaric oxygenation (HBO) on the extracellular matrix of condylar cartilage after mandibular distraction were evaluated. Unilateral distraction was performed on 19 rabbits. Five study groups were included: control, low- and high-dose irradiation, and low- and high-dose irradiation groups with HBO. Additionally, four temporomandibular joints (TMJ) were used as control material. The high-dose irradiated animals were given in the TMJ 22.4 Gy/4 fractions irradiation (equivalent to 50 Gy/25 fractions). Low-dose irradiation group received a 2.2 Gy dosage. Two groups were also given preoperatively HBO 18 x 2.5ATA x 90 min. After a two-week distraction period (14 mm lengthening) and four-week consolidation period the TMJs were removed. Proteoglycan (PG) distribution of the extracellular matrix was evaluated using safranin O staining and collagen I and II using immunohistochemistry. The organization of fibrillar network was studied by polarized light microscopy. On the operated side of the control group and on the unoperated side in all, except for high-dose irradiated group, PG distribution and fibrillar network were normal appearing. In the irradiated groups, with or without HBO, the cartilaginous layer was partially or totally devoid of PG and the network structure was severely damaged. In conclusion, irradiation in conjunction with the pressure applied by distraction causes severe damage to extracellular matrix of condylar cartilage.

Animals↗
PubMed2006

Periosteal distraction osteogenesis: preliminary experimental evaluation in rabbits and dogs.

The aim of this project was to evaluate the potential of bone formation by the distraction of periosteum. Distraction of calvarial bone in 12 rabbits at 0.25 mm a day caused formation of bone in 3 animals, and distraction at 0.5mm a day caused formation of bone in 2. A second trial of alveolar distraction in four dogs using a specifically-designed distraction device showed lack of stability of the device.

Alveolar Ridge Augmentation↗
PubMed2001

Segmental mandibular reconstruction by microincremental automatic distraction osteogenesis: an animal study.

We investigated the reconstruction of a surgically created critical size mandibular defect in sheep using a newly developed automatic distraction device. The device has an implantable component, which is fixed to the mandible to allow the transfer of the transport disc across the created defect, and an external component which is mounted on the activation pump and secured away from the site of bone distraction. Compression of the bellows in the external component causes fluid to be forced through the connecting tube into the distraction component. Distraction at a rate of 1 mm over 24 h was achieved in six sheep. New bone generated at the site of the created defects both anterior (compression side) and posterior (tension side) to the transport disc and had similar radiodensity to the adjacent mandibular bone eight weeks after the completion of distraction.

Angiography↗
PubMed2005

Bi-directional distraction osteogenesis of the alveolar bone using an extraosseous device.

OBJECTIVES: In alveolar distraction, the bone segment tends to incline palatally or lingually, making rigid control of the segments difficult. The aim of this study was to evaluate the usefulness of a newly developed bi-directional extraosseous alveolar distractor (Medartis V2-Alveolar distractor) for pre- and perioperative vector management. MATERIAL AND METHODS: Seven patients with segmental alveolar atrophy following traumatic tooth loss were treated using the distraction device. The patients were followed up clinically and radiologically. Preoperatively, the initial vector for distraction was determined using CT by measuring the cross-section of the bone. The morphology of the alveolar bone was also analyzed in relation to the planned implant position. Postoperatively, the rate of osteogenesis was monitored with plane radiographs and CT scan. RESULTS: All cases had bone deficit at the anterior surface of the alveolar ridge, showing a typical inclination of the long axis of the bone. Using the distractor, vertical distraction and positioning of the segments with labial orientation was possible. After a consolidation period of 12 weeks on average, sufficient bone formation for implant installation was radiologically observable. Histologic and histomorphometric analysis of one bone biopsy showed very dense mineralized bone (area fraction=78%) with a multidirectional, complex architecture. Implant-supported prosthetic oral rehabilitation was successfully performed in all cases. CONCLUSION: All complications observed in this study were related to the bone deficiency at the anterior surface of the alveolar process. If the technique can be improved, this type of bi-directional distraction is a promising method for alveolar bone repair.

Adult↗
PubMed1998

An experimental study of mandibular arch widening in the dog using distraction osteogenesis.

PURPOSE: This study evaluated the amount of skeletal and dental widening of the mandible in the dog produced by using a tooth-borne distraction device. MATERIALS AND METHODS: Four adult mongrel dogs had osteotomies performed in the parasymphysis region and had a tooth-borne distraction appliance placed to widen the mandible 10 mm. The interarch distance between the canines and between the fourth premolar teeth, as well as between the intrabony markers, was compared. RESULTS: The canine teeth moved 95% of the distraction device movement, whereas the bone widened 55% of the distraction device movement. Histological evaluation showed woven bone formation within the distraction gap. CONCLUSION: This study shows that a tooth-borne mandibular widening device will move the teeth significantly more than the bone.

Animals↗
PubMed2005

Alterations in gingival dimensions following rapid canine retraction using dentoalveolar distraction osteogenesis.

The aim of this clinical prospective study was to evaluate the alterations that occurred in the gingival dimensions of canine teeth following dentoalveolar distraction (DAD) during a 12 month follow-up period.The study sample comprised 36 maxillary canines of 18 growing or adult subjects with a mean age of 16.94 years (13.08-25.58 years) at the start of treatment. Full retraction of the canines was achieved in 10.36 +/- 1.93 days (range 8-14 days) at a rate of 0.8 mm/day using a custom-made intraoral rigid tooth-borne distraction device. Before surgery (pre-DAD), immediately after removal of the device (post-DAD), and at 1, 6, and 12 months post-DAD, the plaque index (PI), gingival index (GI), pocket depth (PD) and width of keratinized gingiva were recorded and the width of attached gingiva was calculated. The alterations in clinical measurements among different evaluation periods were analysed by Friedman and repeated measure ANOVA tests. There were significant differences between pre- and post-DAD for PD measurements for all sites, with the highest at the distal site. The palatal sites likewise showed significant differences at the 1, 6, and 12 month follow-up periods compared with the post-DAD period. The buccal sites showed no significant changes at any time point. The width of keratinized gingiva also showed no significant change during the follow-up period, while the width of attached gingiva was significant only between the pre- and post-DAD periods (P < 0.01). On the basis of the above findings, it could be concluded that DAD is an innovative technique with no unfavourable long-term effects on the gingival tissues of rapidly retracted canine teeth.

Adolescent↗
PubMed2003

Vascular leak syndrome of Sprague-Dawley rats in a mandibular distraction osteogenesis study.

Vascular leak syndrome (VLS) is a common and often fatal sequela of multiple bone traumas, and of infectious, toxic, and allergic insults in human patients. Although an animal model for VLS has not been fully established, rats have shown sensitivity to the syndrome that approximates that of the human population. We describe cases of VLS in three-month-old adult and one-month-old Sprague-Dawley rats in an osteogenesis study aimed at optimizing correction of bone hypoplasias and other craniofacial deformities in children, using a mandibular distraction device. In the study reported here, VLS was diagnosed in 40% of the rats that were necropsied after dying or being euthanized early, subsequent to mandibular osteotomy, a procedure that involves minimal bone trauma. The gross and histologic findings, as well as the clinical course of VLS in the rats of the osteogenesis study, were similar to those of documented human cases. Hence, the rat may be a useful animal model to h elp characterize the physiologic and molecular events that accompany this syndrome.

Animals↗
PubMedDate not supplied

Force-displacement behaviour of biological tissue during distraction osteogenesis.

Limb lengthening and bone transport treatments are used frequently, and complications during treatment are common. Knowledge of the origin of tensile forces which resist distraction and the force-displacement response of biological tissues during extension would assist in reducing complication rates. Two tibial diaphyseal lengthenings carried out using an Ilizarov fixator were monitored by a displacement transducer to determine extension of the lengthening tissue (the regenerate bone), and by force transducers to determine tensile forces in the tissues that resist extension. The position of the force vector within a cross-section of the limb at the regenerate (provided by CT) was used to determine the origin of these forces. The muscle groups and adjacent fascia resisting extension were the gastrocnemius in one subject and the anterior and peroneal compartments in the other. In response to distraction, these tissues had relatively high stiffness (> 200 N/mm), less "immediate" displacement (< 35% of long term non-recoverable displacement) and inconsistent force relaxation properties (0-90%). In contrast, when the force vector was located in the vicinity of the regenerate, tissue exhibited lower stiffness (< 50 N/mm) and more immediate displacement (> 65% of long term nonrecoverable displacement), but also exhibited inconsistent force relaxation (0-67%).

Adaptation, Physiological↗
PubMed2001

[Management of maxillary deficiency through distraction osteogenesis. Report of 14 cases].

Maxillary protraction using elastics has been used routinely in patients with maxillary hypoplasia. Internal devices with bone anchorage allows more control of the distracted callus and more predictable results. The use of distraction splints with internal distractors simultaneously provides more accuracy in maxillary hypoplasia treatment. Three techniques using internal maxillary distractors and distraction splints are exposed for treatment of severe or partial maxillary hypoplasia. Fourteen patients have been treated from 1996 january 1 to 2000 june 30: twelve with a severe maxillary hypoplasia, two with a partial hypoplasia, among them eight in childhood or adolescence. The functionnal and aesthetic results have been satisfactory in all cases. Vertical maxillary hypoplasia treated by internal distractors techniques provides better results than traditionals inlay grafted Lefort I osteotomies. Segmental distractions can also be used in combination with classic orthognatic surgery.

Adolescent↗
PubMed2004

Role of guided bone regeneration principle in preventing fibrous healing in distraction osteogenesis at high speed: experimental study in rabbit mandibles.

The formation of fibrous tissues at the distraction gap may result from the accumulation of rapidly migrating fibroblasts at the site of an osteotomy, especially when distraction is rapid. Addition of osteopromotive membranes could theoretically prevent fibroblasts from entering the distraction gap, allowing the osteotomy site to be filled with only osteogenic cells. This study is an attempt to achieve a rapid successful distraction without fibrosis through the use of collagen membranes. Sixteen skeletally mature New Zealand white rabbits were used in this study. They were divided into two groups. One rabbit from each group was excluded from the study because of dislodgement of the distractors. In one group (n = 7), distraction was done as usual. In the other group (n = 7), a collagen membrane surrounded the osteotomy site to be distracted. After a 7-day latency period, distraction started at a rate 2 mm once per day for 5 days. The distractor was left in place for 4 weeks to allow consolidation. Results showed osteogenesis in both groups. Whereas addition of the membrane to distraction increased the quantity of bone formed, absence of the membrane allowed early mineralization (better quality of bone regarding the density). Neither of the two groups showed significant fibrosis or cartilage formation. The endosteum served as a source of blood supply when the periosteum was excluded. The periosteum served as a membrane for guided bone regeneration. Membranes for guided bone regeneration can be used with distraction when the periosteum is lost from trauma or is broken from fast distraction.

Animals↗
PubMed1998

Histologic analysis of distraction osteogenesis in the femoral shaft of the immature rabbit.

A study of the distraction callus in the femur of the growing rabbit was performed. Thirty animals separated into 10 groups were used. Distraction between both ends of a femoral osteotomy induced the formation of a connective callus which subsequently ossified. This callus disappeared between the fourth and the eighth week after the lengthening was completed. The osteogenesis model was of a mixed type, intramembranous and endochondral, with a predominance of the former. The bone healing and the initial signs of remodeling in the newly formed bony tissue were seen at the end of the first week of distraction. The original cortex was resorbed during the lengthening and was progressively substituted by a new cortex, whose formation and remodeling was not finished 24 weeks after the completion of the distraction. Experimental conditions could explain some of the findings.

Animals↗
PubMed1998

Distraction osteogenesis through high energy fractures.

We present a series of three patients with segmental, high energy open tibial fractures with bone loss (2-7 cm), where we have used distraction through a fracture site to replace lost bone. The open fracture was treated by debridement and shortening to eliminate the bone and soft tissue defect. Limb length was restored by distraction instituted through the closed segmental fracture. The length of regenerate formed at the fracture site ranged from 10 to 30 mm. In each case, bone formation at the distracted fracture site was satisfactory and times for regenerate consolidation were similar to those seen in standard corticotomies. These findings suggest that new bone will form in distraction reliably from high-energy fracture sites.

Accidents, Traffic↗
PubMed2006

Distraction osteogenesis of ankylosed front teeth with subsequent orthodontic fine adjustment.

OBJECTIVE: Conventional therapeutic approaches to correct ankylosed anterior teeth in infraposition require compromises involving esthetics and function. The combined approach of distraction and early orthodontic fine adjustment, not yet established as a routine, promises better results concerning the bone conditions and gingival development. CASE HISTORIES: Both female patients had suffered a trauma to the front teeth during early mixed dentition resulting in ankylosed central incisors in infraposition. At the ages of 14 years and 2 months and 15 years and 2 months, respectively, we carried out segment distraction by means of a bone-supported internal distractor followed by orthodontic fine adjustment after having shortened the consolidation phase. Both ankylosed front teeth could be successfully aligned, leading to an increase in bone and harmonization of the gingival margin in the dental arch. At ten and 14 months after the conclusion of treatment, we observed only few deviations in the dental situation compared to posttherapeutic findings. CONCLUSION: From a functional and esthetic point of view, therapy involving combined orthodontics and surgery is superior to conventional therapy. Orthodontic fine adjustment should be considered as a continuation of the distraction procedure.

Child↗
PubMed2002

Soft tissue profile changes of the midface in patients with cleft lip and palate following maxillary distraction osteogenesis: a preliminary study.

OBJECTIVE: The purpose of this study was to examine preoperative to postoperative changes of soft tissue profiles in the midface of cleft patients who underwent maxillary distraction. STUDY DESIGN: Nine cleft patients were examined (distraction group). Lateral cephalograms were obtained preoperatively and 6 months after distraction. Changes in the positions of soft and hard tissue landmarks, the nasolabial angle, and facial height were investigated and compared with those in 9 other cleft patients who underwent conventional maxillary advancement (conventional group). RESULTS: Anterior changes of the soft and hard tissue landmarks were significantly larger in the distraction group than in the conventional group. The distraction group tended to have larger increases in the nasolabial angle and subnasal length, as well as a higher anterior movement ratio for soft to hard tissue. CONCLUSIONS: These results suggest that, in the midfacial profile changes of cleft patients who underwent maxillary distraction, not only is advancement of soft and hard tissue large, but also anterior movement ratio for soft to hard tissue is relatively high.

Adolescent↗
PubMed2001

Bending of the distraction site during mandibular distraction osteogenesis in the rabbit: a model for studying segment control and side effects.

PURPOSE: The purpose of this investigation was to develop an animal model for studying and correcting mandibular distraction side effects. MATERIALS AND METHODS: Twenty-nine rabbits underwent bilateral mandibular distraction. Bending of the mandible was accomplished by offsetting a linear distraction by 35 degrees from the occlusal plane (4 screws per distractor), rotating the anterior segment inferiorly (2 screws per distractor), and removing a 3- or 6-mm wedge of the distraction site. The amount of bite opening varied according to the surgical design. Direct measurements, radiographs, and histology samples were compared. RESULTS: Linear distraction produced a 4-mm anterior open bite and a Class III malocclusion after 2 weeks of distraction. Segmental rotation produced an 8-mm anterior open bite without complications. Removal of a wedge initiated rotation of the anterior segment. A large wedge (6 mm) produced fibrous union in the distraction site. The amount of bite opening or closure depended on the number of surgical screws and position of the distractor. Serial histologic sections showed bone formation at the rotated, triangular distraction site. CONCLUSION: Bite opening or closure can occur from loss of segment control or by altering surgical design. This information is needed to counter unwanted side effects or to plan segment rotations.

Analysis of Variance↗
PubMedDate not supplied

Effects of pulsed electromagnetic field stimulation on distraction osteogenesis in the rabbit tibial leg lengthening model.

The purpose of this study was to determine whether exposure to pulsed electromagnetic field (PEMF) would shorten the healing time of regenerate bone in a rabbit tibial distraction model. Beginning 1 day after surgery, mid-shaft tibial osteotomies, stabilized with external fixators, were distracted 0.25 mm twice daily for 21 days and received either no exposure (sham control) or 1 hour per day exposure to low-amplitude, low-frequency PEMF. Tibiae were tested for torsional strength after 9, 16, and 23 days post-distraction. PEMF-treated tibiae were significantly stronger than shams at all three time points. By 16 days post-distraction, the PEMF group had achieved biomechanical strength essentially equivalent to intact bone. Shams did not achieve normal biomechanical strength even after 23 days post-distraction. In this tibial distraction model, short daily PEMF exposures accelerated consolidation of regenerate bone. Clinical usefulness awaits testing.

Animals↗
PubMed2006

Distraction osteogenesis in a patient with juvenile arthritis.

We present a 26-year-old patient with juvenile-onset arthritis, Alagille's syndrome, micrognathia, and progressive sleep apnea. Despite the presence of significant temporomandibular joint pathology, mandibular distraction was indicated to correct life-threatening sleep apnea. Before distraction, the patient had only 10 mm of maximal interincisal opening and bilateral temporomandibular joint symptomatology. After distraction, the patient's sleep apnea resolved. There was slight improvement in her maximal incisal opening (12 mm) with neither exacerbation nor improvement of her temporomandibular joint symptomatology.

Adult↗
PubMed1992

Distraction osteogenesis of the mandible. An experimental study on sheep.

Distraction bone healing has been studied in long bones but there are only few experiments reported in relation to the mandible. The histological pattern of the healing process after mandibular distraction is described. After osteotomy the mandibles of 17 growing sheep were lengthened by gradual distraction using an external fixation device. The follow-up varied from 0 to 52 weeks. The results indicate that bone healing in mandibles is principally the same as in long bones. Four phases can be observed during the repair process: 1) formation of collagen aligned in the direction of distraction, 2) bone formation over the collagen template, 3) bone union across the distraction gap, and 4) remodelling of the lengthened segment. Some increased osteoblast activity was also seen in the control side.

Animals↗