Dronabinol inhibits alveolar bone remodeling in tooth movement of rats

Caffeine induces alveolar bone loss in rats submitted to orthodontic movement via activation of receptor activator of nuclear factor ҡB, receptor activator of nuclear factor ҡB ligand, and osteoprotegerin pathway

INTRODUCTION

Caffeine is a widely consumed substance with several effects on bone metabolism. This study aimed to investigate the effect of caffeine on the bone tissue of rats submitted to orthodontic movement.

METHODS

Twenty-five male Wistar rats underwent orthodontic movement (21 days) of the first permanent maxillary molars on the left side. The experimental group (caffeine; n = 13) and control group (n = 12) received caffeine and water, respectively, by gavage. Microcomputed tomography was performed to analyze orthodontic movement. Histologic analysis of the inflammatory infiltrate and osteoclast count by tartrate-resistant acid phosphatase were conducted. Maxilla tissue was evaluated for receptor activator of nuclear factor ҡB (RANK), RANK ligand (RANKL), and osteoprotegerin by immunohistochemistry.

RESULTS

Caffeine exhibited a lower bone volume/tissue volume ratio (78.09% ± 5.83%) than the control (86.84% ± 4.89%; P <0.05). Inflammatory infiltrate was increased in the caffeine group compared with the control group (P <0.05). A higher number of tartrate-resistant acid phosphatase-positive cells was observed in the caffeine (9.67 ± 1.73) than in the control group (2.66 ± 0.76; P <0.01). Immunoexpression of RANK and RANKL in the caffeine group was greater than the control (P <0.05).

CONCLUSIONS

The use of caffeine thermogenic induces alveolar bone loss in rats submitted to orthodontic movement via activation of RANK, RANKL, and osteoprotegerin signaling pathways.

Therapeutic dosage of isotretinoin in rats may influence orthodontic tooth movement

Objective Isotretinoin, also known as 13-cis-retinoic acid, is an isomer of tretinoin, the oxidized form of Vitamin A. Orthodontic tooth movement (OTM) is the result of a cascade of inflammatory responses stimulated by a physical element that is the force generated by orthodontic appliances. Isotretinoin is mainly used among adolescents and young adults, and coincidentally it is this age group that also undergoes orthodontic treatment. Materials and Methods Fifty-five animals were used, and they were randomly divided into 11 groups, containing 5 animals in each group. Group 1: Control; Group 2: OTM for 7 days; Group 3: OTM for 14 days; Group 4: Treated with isotretinoin for 14 days with a dosage of 7.5 mg/kg/day; Group 5: Treated with isotretinoin for 14 days with a dosage of 1.0 mg/kg/day; Group 6: Treated with isotretinoin for 21 days with a dosage of 7.5 mg/kg/day; Group 7: Treated with isotretinoin for 21 days with a dosage of 1.0 mg/kg/day; Group 8: Treated with isotretinoin for 14 days with a dosage of 7.5 mg/kg/day and undergoing OTM for 7 days; Group 9: Treated with isotretinoin for 14 days with a dosage of 1.0 mg/kg/day and undergoing OTM for 7 days; Group 10: Treated with isotretinoin for 21 days with a dosage of 7.5 mg/kg/day and undergoing OTM for 14 days; Group 11: Treated with isotretinoin for 21 days with a dosage of 1.0 mg/kg/day and undergoing OTM for 14 days. In Groups 8, 9, 10 and 11, the animals were treated with isotretinoin for 7 days before OTM and maintained during the movement period in the respective groups. Results There was a significant difference in microtomographic parameters, including Trabecular Volume (BV/TV), Trabecular Thickness (Tb.Th), Number of Trabeculae (Tb.N), and Trabecular Separation (Tb.Sp), between the groups. The group that received orthodontic force in conjunction with isotretinoin treatment at a dosage of 7.5 mg/kg/day exhibited lower tooth displacement over a period of 21 days and 14 days. Conclusion Isotretinoin caused a reduction in tooth displacement during OTM when administered at a dose of 7.5 mg/kg/day and isotretinoin did change the microtomographic parameters of treated animals.

The role of cannabinoid receptor 2 in bone remodeling during orthodontic tooth movement

BACKGROUND

The purpose of this study is to explore the effects of CB2 on bone regulation during orthodontic tooth movement.

METHODS

Thirty male mice were allocated into 2 groups (n = 15 in each group): wild type (WT) group and CB2 knockout (CB2-/-) group. Orthodontic tooth movement (OTM) was induced by applying a nickel-titanium coil spring between the maxillary first molar and the central incisors. There are three subgroups within the WT groups (0, 7 and 14 days) and the CB2-/- groups (0, 7 and 14 days). 0-day groups without force application. Tooth displacement, alveolar bone mass and alveolar bone volume were assessed by micro-CT on 0, 7 and 14 days, and the number of osteoclasts was quantified by tartrate-resistant acid phosphatase (TRAP) staining. Moreover, the expression levels of RANKL and OPG in the compression area were measured histomorphometrically.

RESULTS

The WT group exhibited the typical pattern of OTM, characterized by narrowed periodontal space and bone resorption on the compression area. In contrast, the accelerated tooth displacement, increased osteoclast number (P < 0.0001) and bone resorption on the compression area in CB2-/- group. Additionally, the expression of RANKL was significantly upregulated, while OPG showed low levels in the compression area of the CB2 - / - group (P < 0.0001).

CONCLUSIONS

CB2 modulated OTM and bone remodeling through regulating osteoclast activity and RANKL/OPG balance.

Examining the role of cannabinoids on osteoporosis: a review

PURPOSE

Prior research studies have shown that the endocannabinoid system, influenced by CBD and THC, plays a role in bone remodeling. As both the research on cannabis and use of cannabis continue to grow, novel medicinal uses of both its constituents as well as the whole plant are being discovered. This review examines the role of cannabinoids on osteoporosis, more specifically, the endocannabinoid system and its role in bone remodeling and the involvement of the cannabinoid receptors 1 and 2 in bone health, as well as the effects of Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD), and synthetic cannabinoids on bone.

METHODS

A comprehensive literature search of online databases including PUBMED was utilized.

RESULTS

A total of 29 studies investigating the effects of cannabis and/or its constituents as well as the activation or inactivation of cannabinoid receptors 1 and 2 were included and discussed.

CONCLUSION

While many of the mechanisms are still not yet fully understood, both preclinical and clinical studies show that the effects of cannabis mediated through the endocannabinoid system may prove to be an effective treatment option for individuals with osteoporosis.

Associations between Oral Health and Cannabis Use among Adolescents and Young Adults: Implications for Orthodontists

Cannabis use is prevalent among adolescents and young adults in the US. Virtually all modes of cannabis consumption involve the oral cavity, and previous studies have linked cannabis use with poorer oral health. We sought to identify associations between cannabis use and various oral health outcomes and behaviors among individuals 12-25 years of age, and to discuss implications for orthodontists who largely interact with this age group over an extended period of treatment time. We examined data from patient electronic health records (N = 14,657) obtained between 2015 and 2021. Associations between lifetime and current self-reported cannabis use and several oral health outcomes or related behaviors that reflect periodontal health, caries status, oral lesions, and physical integrity of tooth structure and restorations were examined in a bivariable and multivariable manner, controlling for patient age, sex, and self-reported tobacco and alcohol use. Reporting lifetime cannabis use was associated with higher risk for having oral lesions (aPR = 1.41, 95% CI: 1.07-1.85), bruxism (aPR = 1.31, 95% CI: 1.09-1.58), and frequent consumption of sugary beverages and snacks (aPR = 1.27, 95% CI: 1.12-1.41). Reporting current cannabis use was associated with higher risk for oral lesions (aPR = 1.45, 95% CI: 1.03-2.06) and frequent consumption of sugary beverages and snacks (aPR = 1.26, 95% CI: 1.07-1.48). Cannabis users aged 12-25 are at increased risk for bruxism, oral lesions, and frequent consumption of sugary beverages and snacks. Orthodontists and other dental professionals should probe for drug use and be cognizant of increased risk for oral health problems in patients that report actively using cannabis.

Extraction and Analysis of Foot Bone Shape Features Based on Deep Learning

With the rapid development of artificial intelligence, more and more researchers and research institutions begin to pay attention to the bone feature recognition field. Human bone movement is very complex, and human bone shape recognition technology can be widely used in medical treatment, sports, and other fields. At present, there are mainly two kinds of methods for extracting the shape features of human foot bone based on optical image acquisition technology and sensor information perception technology. However, due to the interference factors such as target posture change, camera shake, and individual behavior differences, it is still a very challenging task to design a robust algorithm for extraction and analysis of foot bone shape features. In recent years, convolutional neural network- (CNN-) based foot contour feature recognition methods emerge one after another and have made breakthrough progress. How to use and how to fully explore the potential relationship of various characteristics contained in the foot bone data and how to enhance the robustness of view changes and other aspects need to be further studied. In this context, this paper proposed an improved CNN model, which not only has the capability of deep feature extraction of the CNN model but also can obtain the optimal model parameters with the combination of particle swarm optimization algorithm. The effectiveness of the proposed method in the extraction and analysis of foot bone shape features is verified in the simulation experiment.