Hyperbaric Oxygen Therapy to Minimize Orthodontic Relapse in Rabbits

OBJECTIVES

 The purpose of the present study was to discover how hyperbaric oxygen therapy (HBOT) could reduce orthodontic relapse by altering the expressions of hypoxia-inducible factor (HIF)-1 messenger ribonucleic acid (mRNA), type I collagen (Col I), and matrix metalloproteinase-1 (MMP-1) in the gingival supracrestal fibers in rabbits.

MATERIALS AND METHODS

 This study involved 44 male rabbits (Oryctolagus cuniculus) randomly divided into the normal group (K0), the orthodontic group without HBOT (K1), and the orthodontic group with HBOT (K2). Following orthodontic separation of the two upper central incisors, a retention phase and relapse assessment were performed. The HBOT was performed for a period of 2, 4, 6, 8, and 10 days after retention. HIF-1α transcription was assessed employing real-time polymerase chain reaction, whereas Col I and MMP-1 proteins were examined using immunohistochemistry. The orthodontic relapse was measured clinically using a digital caliper.

STATISTICAL ANALYSIS

 We used the one-way analysis of variance followed by Tukey's post hoc for multiple comparisons to measure differences between pairs of means; a p-value of 0.05 was considered statistically significant.

RESULTS

 HBOT significantly increased the HIF-1α mRNA expression (p = 0.0140), increased Col I (p = 0.0043) and MMP-1 (p = 0.0068) on the tensioned and pressured side of the gingival supracrestal fibers, respectively, and clinically decreased the relapse (p = 3.75 × 10-40).

CONCLUSION

 HBOT minimizes orthodontic relapse by influencing HIF-1α expression, collagen synthesis (Col I), and degradation (MMP-1). This result suggests that HBOT has the potential to be used as an adjunctive method in the orthodontic retention phase.

Effect of local application of bone morphogenetic protein -2 on experimental tooth movement and biological remodeling in rats

Background: This study attempts to detect the potential effects of local bone morphogenetic protein -2 (BMP-2) on orthodontic tooth movement and periodontal tissue remodeling. Methods: Forty adult SD rats were randomly divided into four groups: blank control group, unilateral injection of BMP-2 on the pressure side or tension side of orthodontic teeth and bilateral injection of BMP-2. Their maxillary first molar was moved by a 30 g constant force closed coil spring. 60 μL of BMP-2 with a concentration of 0.5 μg/mL was injected into each part at a time. In addition, three rats were selected as healthy control rats without any intervention. Fluorescent labeled BMP-2 was used to observe the distribution of exogenous BMP-2 in tissues. Micro-CT was used to measure the microscopic parameters of tooth displacement, trabecular bone and root absorption volume. Three different histological methods were used to observe the changes of tissue remodeling, and then the number of osteoclasts and the content of collagen fibers were calculated. Results: Compared with the blank control group, BMP-2 injection reduced the movement distance and increased the collagen fiber content and bone mass (p < 0.01). There was no significant difference in tooth movement distance, BV/TV ratio and BMD between injection sites in unilateral injection group (p > 0.05). In the case of bilateral injection of BMP-2, the osteogenesis is enhanced. Unilateral injection of BMP-2 did not promote root resorption, but double injection showed root resorption (p < 0.01). Conclusion: Our study does show that the osteogenesis of BMP-2 is dose-dependent rather than site-dependent when a certain amount of BMP-2 is applied around orthodontic teeth. Local application of BMP-2 around orthodontic teeth in an appropriate way can enhance bone mass and tooth anchorage without increasing the risk of root absorption volume. However, high levels of BMP-2 may cause aggressive root resorption. These findings are of great significance, that is, BMP-2 is an effective target for regulating orthodontic tooth movement.

Potential Use of Hyperbaric Oxygen Therapy in Orthodontic Treatment: A Systematic Review of Animal Studies

Understanding the fundamental principles of tooth movement could reduce the duration of treatment and achieve a stable outcome, resulting in patient satisfaction. Hyperbaric oxygen therapy was a modality in which a patient inhaled 100% O₂ while subjected to high atmospheric pressure. Hyperbaric oxygen therapy facilitated the supply of oxygen to the human body's organs and tissues and served a variety of applications, including patient care and wound treatment. This review article aimed to describe animal studies of the potential effects of hyperbaric oxygen therapy in orthodontic therapy. It was conducted using a systematic literature review method, including searching PubMed and Google Scholar for publications relevant to the research topics. The search was filtered to include only research on orthodontic treatment and hyperbaric oxygen therapy and was published in any year. Articles that did not specify biological components of orthodontic tooth movement (OTM) were excluded. The Preferred Reporting Items identified the papers for the Systematic Reviews and Meta-Analyses (PRISMA) strategy, which resulted in the selection of 11 publications. Hyperbaric oxygen therapy affected parameters of biomarkers representing the clinical, molecular, and cellular biology of bone formation and resorption in periodontal tissues in responding to orthodontic physical forces, including alkaline phosphatase, collagen synthesis, osteoblast, osteoclast, osteocyte, type I collagen, vascular endothelial growth factor, osteocalcin, fibroblast, matrix metalloproteinase-8, transforming growth factor-β, partial pressure of oxygen, partial pressure of carbon dioxide, trabecular bone density, and tooth mobility. Hyperbaric oxygen therapy induced an inflammatory response to follow OTM events during active orthodontic therapy. Hyperbaric oxygen therapy might play a role in the tissue healing process during passive treatment. Nonetheless, additional research should be conducted to establish the efficacy of hyperbaric oxygen therapy in orthodontics.

SMAD 3, Integrin and VEGF Expression in a Periodontal Ligament During Orthodontic Tooth Movement Induced by Hyperbaric Oxygen Therapy and Stichopus hermanii

Purpose

The aim of this study is to analyze SMAD 3, integrin and VEGF expressions in the periodontal ligament during orthodontic tooth movement induced by hyperbaric oxygen therapy and Stichopus hermanii.

Materials and Methods

Thirty Cavia cobaya were divided into 5 groups, namely, a normal control group (KN) without installation of helical springs or administration of HBOT and Stichopus hermanii gel. The negative control K(-) had helical spring without administration of HBOT and Stichopus hermanii gel for 14 days, while P1 had helical spring for 14 days then on day 3–14, Stichopus hermanii gel was added. Also, the helical spring was installed in P2 for 14 days then on day 8–14, HBOT 2.4 ATA was added 3 × 30 minutes a day, while P3 had helical spring for 14 days then on day 3–14, the gel was applied, and on day 8–14, HBOT 2.4 ATA was administered 3 × 30 minutes a day. Furthermore, SMAD3, integrin, and VEGF expressions were examined using immunohistochemical staining.

Results

SMAD3, integrins, and VEGF expressions showed significant differences within the groups. The combination of HBOT and Stichopus hermanii increased the expression of SMAD3 and VEGF compared to the single administration of Stichopus hermanii. The combination treatment also decreased integrin expression compared to a single HBOT administration.

Conclusion

The combination of HBOT and Stichopus hermanii increases the expression of SMAD3, integrins, and VEGF compared to control but did not show significant differences compared to single HBOT treatment.

Nonhealing Wounds Caused by Brown Spider Bites: Application of Hyperbaric Oxygen Therapy

BACKGROUND

Bites by Loxosceles spiders (also known as recluse spiders or brown spiders) can cause necrotic ulcerations of various sizes and dimensions. The current standard of care for brown spider bites includes analgesics, ice, compression, elevation, antihistamines, and surgical debridement. Hyperbaric oxygen therapy (HBOT) in the treatment of brown spider bites has been administered in the early stage of ulceration, or 2 to 6 days after the bite. Unfortunately, the diagnosis of spider bite-related ulcers is often delayed and weeks or months may elapse before HBOT is considered.

OBJECTIVE

To evaluate the effect of HBOT on nonhealing wounds caused by brown spider bites in the late, chronic, nonhealing stage.

METHODS

Analysis of 3 patients with brown spider-bite healing wounds treated at The Sagol Center for Hyperbaric Medicine and Research in Israel. Patients presented 2 to 3 months after failure of other therapies including topical dressings, antibiotics, and corticosteroids. All patients were treated with daily 2 ATA (atmospheres absolute) with 100% oxygen HBOT sessions.

RESULTS

All 3 patients were previously healthy without any chronic disease. Their ages were 30, 42, and 73 years. They were treated once daily for 13, 17, and 31 sessions, respectively. The wounds of all 3 patients healed, and there was no need for additional surgical intervention. There were no significant adverse events in any of the patients.

CONCLUSIONS

Microvascular injury related to brown spider bites may culminate in ischemic nonhealing wounds even in a relatively young, healthy population. Hyperbaric oxygen therapy should be considered as a valuable therapeutic tool even months after the bite.

Comparative study of the osseous healing process following three different techniques of bone augmentation in the mandible: an experimental study

The aim of this study was to evaluate the osseointegration of three different bone grafting techniques. Forty-eight mature New Zealand rabbits were divided randomly into three groups of 16 each. Horizontal augmentation was performed on the corpus of the mandible using three different techniques: free bone graft (FBG), free periosteal bone graft (PBG), pedicled bone flap (BF). The animals were sacrificed at postoperative weeks 1, 3, or 8. Specimens were decalcified for histological examination, and histomorphometric measurements were performed. The histological evaluation demonstrated bony fusion between the grafts and the augmented mandibular bone after 8 weeks in all groups. At week 8, the bone volume was significantly greater in the BF group than in the FBG (P<0.001) and PBG (P=0.001) groups, and also the trabecular thickness was significantly greater than in the FBG (P=0.015) and PBG (P=0.015) groups. Trabecular separation was significantly lower in the BF group than in the FBG group at week 8 (P=0.015). BF demonstrated greater osseous healing capacity compared to FBG and PBG. The preserved vascularization in BF improves the bone quality in mandibular bone augmentations.

Laser-induced alveolar bone changes during orthodontic movement: a histological study on rodents

OBJECTIVE

The aim of this study was to assess by light microscopy changes in alveolar bone during orthodontic movement in rats.

BACKGROUND

Orthodontic movement causes both removal and deposition of bone tissue. The use of laser phototherapy (LPT) is considered an enhancement factor for bone repair.

METHODS

Thirty Wistar rats were divided into two groups (n = 15) and subdivided according to animal death (7,13, and 19 days). Half of the animals in each group were treated with LPT during orthodontic movement. After animal death, specimens were processed and underwent histological and semi-quantitative analyses (HE and Sirius red).

RESULTS

LPT-irradiated specimens showed significantly higher numbers of osteoclasts when compared with controls at both 7 (p = 0.015) and 19 (p = 0.007) days, as well as significant increases in the number of osteoblasts (p = 0.015) between days 7 and 13. The amount of collagen matrix was significantly reduced between days 7 and 13 at both pressure and tension sites in controls (p = 0.015) but not in LPT-treated animals. LPT-treated subjects showed significantly greater deposition of collagen matrix at the pressure site at both the thirteenth (p = 0.007) and nineteenth days (p = 0.001). At the tension site, a significant increase in the amount of collagen matrix was observed in non-irradiated specimens (p = 0.048) between days 7 and 19.

CONCLUSIONS

LPT caused significant histological changes in the alveolar bone during induced tooth movement, including alterations in the number of both osteoclasts and osteoblasts and in collagen deposition in both pressure and tension areas.

The Effects of Hyperbaric Oxygen on Tooth Movement into the Regenerated Area after Distraction Osteogenesis

Objective

To analyze the effect of hyperbaric oxygen on newly formed bone in distracted areas surrounding the root of a moving tooth by histological and radiological analysis. It was hypothesized that the application of hyperbaric oxygen to a tooth moving into the distracted area would accelerate ossification and vascularization of newly formed bone in the distracted space.

Design

Ten dogs were used. After creating a 10-mm-long bone defect, a bony segment was prepared and translocated into the defect area at a rate of 1 mm/d for 10 days. Following the distraction period, tooth movement was started and the dogs were divided into two groups. The HBO group received hyperbaric oxygen; whereas, the control group did not. At 150 days after tooth movement, the distracted area around the moving tooth was evaluated radiologically and histologically. Differences between groups were confirmed by a Mann-Whitney U test.

Results

Trabecular bone density and cortical and subcortical bone areas measured by peripheral quantitative computed tomography in the HBO group were significantly higher than those in the control group. Histological observations revealed regenerated bone and blood vessels formation in the tension site of the moving tooth in the HBO group. The regenerated bone structure measured by bone histomorphometry was larger and more active in bone formation in the HBO group than in the control group.

Conclusions

Applying hyperbaric oxygen to tooth movement into a distracted area appears to accelerate ossification and vascularization of regenerated bone in the that area.