Studying Orthodontic Tooth Movement in Mice.

Orthodontic tooth movement (OTM) represents a dynamic process in which the alveolar bone undergoes resorption at compression sites and deposition at tension sites, orchestrated by osteoclasts and osteoblasts, respectively. This mechanism serves as a valuable model for studying various aspects of bone adaptation, including root resorption and the cellular response to mechanical force stimuli. The protocol outlined here offers a straightforward approach to investigate OTM, establishing 0.35 N as the optimal force in a mouse model employing a nickel-titanium (NiTi) coil spring. Utilizing micro-computed tomography analysis, we quantified OTM by assessing the discrepancy in the linear distance at the cement-enamel junction. The evaluation also included an analysis of orthodontic-induced inflammatory root resorption, assessing parameters such as root mineral density and the percentage of root volume per total volume. This comprehensive protocol contributes to advancing our understanding of bone remodeling processes and enhancing the ability to develop effective orthodontic treatment strategies.

Diagnosis and rehabilitation of an infant with palatal mucormycosis: A clinical report and systematic literature review.

STATEMENT OF PROBLEM: Oral mucormycosis is uncommon in pediatric patients with hematolymphoid diseases. Prosthetic rehabilitation is challenging, and protocols are scarce in the literature. PURPOSE: The purpose of this clinical report and systematic literature review of case reports and case series was to describe the clinicopathologic aspects of oral mucormycosis and the interim prosthetic rehabilitation of an affected infant. MATERIAL AND METHODS: The clinical lesions were ulcerative and necrotic with underlying bone exposure that affected the hard palate. The affected area underwent surgical debridement, and histopathologic analysis was performed. A literature search in PubMed/MEDLINE, Embase, Scopus, and Web of Science up to October 2023 was performed. RESULTS: The histopathological features were consistent with mucormycosis. Topical and systemic antifungals were prescribed. Tooth eruption was insufficient, and an acetate plate without clasp retention, but still with adequate retention, was fabricated. Articulatory, masticatory, and swallowing functions were restored, preventing the passage of food and fluids into the oroantral cavities. Twenty-five articles describing 26 patients with oral mucormycosis related to hematolymphoid disorders affecting the pediatric population were identified. None of the authors of these articles provided information about oral rehabilitation. CONCLUSIONS: Early diagnosis and treatment are essential to increasing the chances of survival for infants affected by oral mucormycosis. Custom-made rehabilitation should be provided to restore oral function and improve the patient's general health.

Kinetics of neutrophil extracellular traps and cytokines in oral mucositis and Candida infection.

OBJECTIVE: This study investigated the concentrations of neutrophil extracellular traps (NET) and salivary cytokines (IL-1ß, IL-6, IL-8/CXCL8, TNF, and TGF-ß1) in patients undergoing chemotherapy and their associations with oral mucositis (OM) and Candida infection. MATERIALS AND METHODS: This prospective longitudinal study performed at a Brazilian service included 60 adults diagnosed with hematolymphoid diseases. Saliva samples were collected on days D0, D3, D10, and D15. Cytokines were analyzed by ELISA and NET formation by identification of the myeloperoxidase-DNA complex. Oral Candida spp. was cultured. RESULTS: OM occurred in 43.3% of patients and oral candidiasis in 20%. However, 66% of individuals had positive cultures for C. albicans. Higher concentrations of IL-6, IL-8/CXCL8, and TNF and lower concentrations of TGF-ß1 were observed in patients with OM. C. albicans infection contributed to the increase in IL-8/CXCL8, TGF-ß1, and TNF. Individuals with OM or with oral candidiasis had significant reductions in NET formation. In contrast, individuals with C. albicans and with concomitant C. albicans and OM exhibited higher NET formation. CONCLUSION: The kinetics of cytokine levels and NET formation in chemotherapy-induced OM appears to be altered by Candida infection, even in the absence of clinical signs of oral candidiasis.

Orthodontic treatment during pregnancy, lactation, and postmenopausal period: a questionnaire development.

This study aimed to develop and validate a self-administered questionnaire in Brazilian Portuguese to verify the level of knowledge of orthodontists in the care of pregnant, lactating, and postmenopausal women, named "Considerations on Orthodontic Treatment during Pregnancy, Lactation, and Postmenopausal Periods." The development and validation of the questionnaire consisted of the following steps: a) item generation; b) item reduction; c) questionnaire design; and d) validity and reliability tests in a cross-sectional study with 258 orthodontists working in the field from different Brazilian states. A total of 60 orthodontists participated in test-retest over a mean period of 45 days. The preliminary questionnaire consisted of a total of 60 questions. After item reduction, 40 questions were selected for the final version of the questionnaire, with eight questions about pregnant women; six about lactating women; 18 about postmenopausal women, and eight about general knowledge in dentistry. Each item had three response options in the Likert scale format. Face and content validity analysis, reliability assessment through internal consistency (Cronbach's alpha and McDonald's omega), and test-retest reliability through the intraclass correlation coefficient (ICC) and Spearman's correlation coefficient were performed. Face and content validity indicated that the questionnaire was considered valid, objective, and easily understandable. The questionnaire had good internal consistency (Cronbach's alpha = 0.77; McDonald's omega = 0.78) and good test-retest reliability (ICC = 0.71; Spearman's correlation coefficient = 0.51). The questionnaire was considered valid and reliable to assess the level of knowledge of orthodontists in the care of pregnant, lactating, and postmenopausal women.

Influence of risedronate on orthodontic tooth movement in rodents: a systematic review and case report.

INTRODUCTION: Bisphosphonates have an inhibitory impact on osteoclastic activity, reducing bone resorption. However, the influence of risedronate on tooth movement is not well-defined. OBJECTIVE: This systematic review assessed the effect of risedronate intake on orthodontic tooth movement. A case report was also provided. METHODS: Two independent reviewers searched six databases (PubMed, Web of Science, Ovid, Lilacs, Scopus, and Open Grey). The searches were carried out in April/2020, and an update was set in place in June/2023. Therefore, the searches considered a timeline from the databases' inception date until June/2023, with no publication date and/or language restrictions. The clinical question focused on evaluating the orthodontic tooth movement and relapse movement (Outcome) in animals (Population) exposed to risedronate (Exposure), compared to control groups (Comparison). The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were applied, and the protocol was registered in PROSPERO (CRD42020168581). The risk of bias was determined using the Systematic Review Centre for Laboratory Animal Experimentation protocol (SYRCLE). RESULTS: Two studies in rats and one in guinea pigs were included in the systematic review. The studies reported a decrease in orthodontic tooth movement, a reduction in the relapse movement, and a reduced number of positive tartrate-resistant acid phosphatase (TRAP) cells, with a significantly reduced number of bone gaps after the administration of risedronate in rats. A case report illustrated the effects of risedronate administration in one patient. CONCLUSION: Based on the systematic review, risedronate seems to impair orthodontic tooth movement and relapse due to a decrease in bone resorption cells.

Protective Effect of Bovine Milk Extracellular Vesicles on Alveolar Bone Loss.

SCOPE: Bovine milk extracellular vesicles (MEVs) have demonstrated therapeutic potential in regulating bone cell activity. However, the outcome of their use on alveolar bone loss has not yet been demonstrated. METHODS AND RESULTS: This study evaluates the effect of oral administration of MEVs on ovariectomized (OVX) mice. There is a reduced height of the alveolar bone crest in OVX mice by MEVs treatment, but the alveolar bone parameters are not altered. OVX mice are then submitted to a force-induced bone remodeling model by orthodontic tooth movement (OTM). MEVs-treated mice have markedly less bone remodeling movement, unlike the untreated OVX mice. Also, OVX mice treated with MEVs show an increased number of osteoblasts and osteocytes associated with higher sclerostin expression and reduce osteoclasts in the alveolar bone. Although the treatment with MEVs in OVX mice does not show differences in root structure in OTM, few odontoclasts are observed in the dental roots of OVX-treated mice. Compared to untreated mice, maxillary and systemic RANKL/OPG ratios are reduced in OVX mice treated with MEVs. CONCLUSION: Treatment with MEVs results in positive bone cell balance in the alveolar bone and dental roots, indicating its beneficial potential in treating alveolar bone loss in the nutritional context.

Orthodontic treatment during pregnancy, lactation, and postmenopausal period: a questionnaire development

Abstract This study aimed to develop and validate a self-administered questionnaire in Brazilian Portuguese to verify the level of knowledge of orthodontists in the care of pregnant, lactating, and postmenopausal women, named "Considerations on Orthodontic Treatment during Pregnancy, Lactation, and Postmenopausal Periods." The development and validation of the questionnaire consisted of the following steps: a) item generation; b) item reduction; c) questionnaire design; and d) validity and reliability tests in a cross-sectional study with 258 orthodontists working in the field from different Brazilian states. A total of 60 orthodontists participated in test-retest over a mean period of 45 days. The preliminary questionnaire consisted of a total of 60 questions. After item reduction, 40 questions were selected for the final version of the questionnaire, with eight questions about pregnant women; six about lactating women; 18 about postmenopausal women, and eight about general knowledge in dentistry. Each item had three response options in the Likert scale format. Face and content validity analysis, reliability assessment through internal consistency (Cronbach's alpha and McDonald's omega), and test-retest reliability through the intraclass correlation coefficient (ICC) and Spearman's correlation coefficient were performed. Face and content validity indicated that the questionnaire was considered valid, objective, and easily understandable. The questionnaire had good internal consistency (Cronbach's alpha = 0.77; McDonald's omega = 0.78) and good test-retest reliability (ICC = 0.71; Spearman's correlation coefficient = 0.51). The questionnaire was considered valid and reliable to assess the level of knowledge of orthodontists in the care of pregnant, lactating, and postmenopausal women.

Targeting phosphatidylinositol-3-kinase for inhibiting maxillary bone resorption.

Previous studies have suggested a role of phosphatidylinositol-3-kinase gamma (PI3Kγ) in bone remodeling, but the mechanism remains undefined. Here, we explored the contribution of PI3Kγ in the resorption of maxillary bone and dental roots using models of orthodontic tooth movement (OTM), orthodontic-induced inflammatory root resorption, and rapid maxillary expansion (RME). PI3Kγ-deficient mice (PI3Kγ-/- ), mice with loss of PI3Kγ kinase activity (PI3KγKD/KD ) and C57BL/6 mice treated with a PI3Kγ inhibitor (AS605240) and respective controls were used. The maxillary bones of PI3Kγ-/- , PI3KγKD/KD , and C57BL/6 mice treated with AS605240 showed an improvement of bone quality compared to their controls, resulting in reduction of the OTM and RME in all experimental groups. PI3Kγ-/- mice exhibited increased root volume and decreased odontoclasts counts. Consistently, the pharmacological blockade or genetic deletion of PI3K resulted in increased numbers of osteoblasts and reduction in osteoclasts during OTM. There was an augmented expression of Runt-related transcription factor 2 (Runx2) and alkaline phosphatase (Alp), a reduction of interleukin-6 (Il-6), as well as a lack of responsiveness of receptor activator of nuclear factor kappa-Β (Rank) in PI3Kγ-/- and PI3KγKD/KD mice compared to control mice. The maxillary bones of PI3Kγ-/- animals showed reduced p-Akt expression. In vitro, bone marrow cells treated with AS605240 and cells from PI3Kγ-/- mice exhibited significant augment of osteoblast mineralization and less osteoclast differentiation. The PI3Kγ/Akt axis is pivotal for bone remodeling by providing negative and positive signals for the differentiation of osteoclasts and osteoblasts, respectively.

A new way of analyzing tooth movement using universal coordinate system geometry single point superposition in a 3D model.

INTRODUCTION: Superposing 3D models is an imminent need. However, current methods rely on marking multiple points on the maxilla and mandible, which could increase point marking and overlapping errors. OBJECTIVE: This study aimed at developing a method for superimposing 3D models of the maxillary and mandibular arches with Autodesk Inventor® engineering software, using a single universal coordinate system (UCS) point superposition. METHODS: A total of 104 STL (stereolithography) models of the maxillary and mandibular arches exported from My iTero® platform were retrospectively selected, in which T0 and T1 were the initial and refinement periods, respectively (n=26 per group). The X, Y, and Z coordinates associated with a single point in each arch were inserted into the models with SlicerCMF® software for model orientation. The arch models with UCS registration were transferred to Autodesk Inventor® for superimposition and to measure tooth movements performed during Invisalign® treatment. Arch expansion, intrusion and rotation were analyzed by two examiners. The statistics were performed using intraclass correlation coefficients (ICC), Dahlberg's formula, and t-test (p<0.05). RESULTS: A reliable method of superimposing 3D digital models using a single UCS point in the maxilla and mandible was developed. ICC showed excellent intra- and inter-examiner correlation (ICC>0.90). A systematic error was not found concerning linear and angular measurements (<1mm and <1.5°, respectively). Digital dental movements could be analyzed, including arch expansion, dental intrusion, and tooth rotation. CONCLUSIONS: The developed method was proven reliable and reproducible for superimposing 3D models of the maxillary and mandibular arches by using UCS system.

Effects of bisphenol A on murine salivary glands and human tumor cell lines.

Bisphenol A (BPA) is an endocrine-disrupting chemical with a potential role in endocrine cancers. However, the effects of BPA on the salivary glands have been barely explored. We investigated the impact of in vivo sub-chronic exposure to BPA and its in vitro effects on human salivary gland mucoepidermoid carcinoma cell lines. Male and female mice were exposed to BPA (30 mg/kg/day). Sublingual and submandibular salivary glands from an estrogen-deficiency model were also analyzed. BPA concentration in salivary glands was evaluated by gas chromatography coupled to ion trap mass spectrometry. Immunohistochemical analysis using anti-p63 and anti-α-SMA antibodies was performed on mouse salivary gland tissues. Gene expression of estrogen receptors alpha and beta, P63 and α-SMA was quantified in mouse salivary gland and/or mucoepidermoid (UM-HMC-1 and UM-HMC-3A) cell lines. Cell viability, p63 and Ki-67 immunostaining were evaluated in vitro. BPA disrupted the tissue architecture of the submandibular and sublingual glands, particularly in female mice, and increased the expression of estrogen receptors and p63, effects that were accompanied by significant BPA accumulation in these tissues. Conversely, ovariectomy slightly impacted BPA-induced morphological changes. In vitro, BPA did not affect the proliferation of neoplastic cells, but augmented the expression of p63 and estrogen receptors. The present data highlight a potential harmful effect of BPA on salivary gland tissues, particularly in female mice, and salivary gland tumor cells. Our findings suggest that estrogen-dependent pathways may orchestrate the effects of BPA in salivary glands.

Skeletal effects following developmental flame-retardant exposure are specific to sex and chemical class in the adult Wistar rat.

Introduction: Accumulating evidence reveals that endocrine disrupting chemicals (EDCs) can disrupt aspects of metabolic programming, suggesting that skeletal development may be at risk, a possibility that is rarely examined. The commercial flame retardant (FR) mixture, Firemaster 550 (FM 550), has repeatedly been shown to negatively influence metabolic programming, raising concerns that skeletal integrity may consequently be impaired. We have previously shown that gestational and lactational exposure to 1,000 µg FM 550 negatively affected sex-specific skeletal traits in male, but not female, rats assessed at 6 months of age. Whether this outcome is primarily driven by the brominated (BFR) or organophosphate ester (OPFR) portions of the mixture or the effects persist to older ages is unknown. Materials and methods: To address this, in the present study, dams were orally exposed throughout gestation and lactation to either 1,000 µg BFR, 1,000 µg OPFR, or 2,000 µg FM 550. Offspring (n = 8/sex/exposure) were weaned at PND 21 and assessed for femoral cortical and trabecular bone parameters at 8 months of age by high-resolution X-ray micro-computed tomography (micro-CT). Serum levels of serotonin, osteocalcin, alkaline phosphatase, and calcium were quantified. Results: FM 550 affected both sexes, but the females were more appreciably impacted by the OPFRs, while the males were more vulnerable to the BFRs. Conclusion: Although sex specificity was expected due to the sexual dimorphic nature of skeletal physiology, the mechanisms accounting for the male- and female-specific phenotypes remain to be determined. Future work aims to clarify these unresolved issues.

Extracellular Vesicles in Bone Remodeling and Osteoporosis.

Osteoporosis is a systemic disorder characterized by bone mass loss, leading to fractures due to weak and brittle bones. The bone tissue deterioration process is related to an impairment of bone remodeling orchestrated mainly by resident bone cells, including osteoblasts, osteoclasts, osteocytes, and their progenitors. Extracellular vesicles (EVs) are nanoparticles emerging as regulatory molecules and potential biomarkers for bone loss. Although the progress in studies relating to EVs and bone loss has increased in the last years, research on bone cells, animal models, and mainly patients is still limited. Here, we aim to review the recent advances in this field, summarizing the effect of EV components such as proteins and miRNAs in regulating bone remodeling and, consequently, osteoporosis progress and treatment. Also, we discuss the potential application of EVs in clinical practice as a biomarker and bone loss therapy, demonstrating that this rising field still needs to be further explored.

Bone strength is reduced in a neonatal androgenized rat model.

Background: Whether polycystic ovary syndrome (PCOS) affects bone health during a woman's lifespan remains controversial. An androgenized rodent model replicated many metabolic and reproductive features of women with PCOS, and we aimed to use it to investigate the impact of androgens on microarchitecture (by micro-CT), bone mechanical strength, bone formation and resorption markers in rats with intact ovaries (SHAM) who underwent oophorectomy. Methods: Wistar rats (Rattus norvegicus albinus) were employed for the experiments in this study. The protocol of androgenization consisted of the application of 1.25 mg s.c. testosterone propionate beteween days 2-5 of life, while the controls received the same amount of corn oil s.c. as previously established. Androgenized SHAM rats exhibited chronic anovulation identified by vaginal cytology and a reduction in the proportion of corpus luteum in the ovary in comparison to control SHAM rats. The realization of the ovariectomy or SHAM procedure occurred on Day 100 of life. All groups (n = 8) were followed-up for 180 days to address the study endpoints. Results: Micro-CT from androgenized female rats (SHAM) showed a divergence between the trabecular and cortical bone profiles. Compared to SHAM controls, these rats had an increase in trabecular bone mass with a diminution in bone resorption C-terminal telopeptide of type 1 collagen (CTX) (p < 0.05), a concomitant decrease in cortical area and thickness in the femur, and a reduction in the strength of the femur on the mechanical test (p < 0.01). Conclusions: Our results suggest that a reduction in the cortical thickness and cortical area observed in PCOS model rats was associated with a reduced strength of the femur, despite increased trabecular formation. Ovariectomy in the androgenized OVX group limited the progression rate of cortical bone loss, resulting in bone resistance and cortical thickness comparable to those observed in the control OVX group.

The Effects of NAM on the Symmetry of the Face and Maxillary Arch in Babies With Unilateral Cleft.

The study aimed to evaluate the effect of nasoalveolar molding (NAM) therapy through reverse engineering, or its absence, to obtain symmetry of the face and maxillary arch. Twenty-six babies with unilateral cleft lip and palate received treatment with NAM, and 12 babies with unilateral cleft lip and palate without presurgical orthopedics (control group). Patients were molded and photographed in 2-stages: the first month of life (T1/pre) and after the use of NAM/before the cheiloplasty (T2/post). In the digital models, the analyses performed were arch perimeter, arch length, and labial frenulum angle. The photographs allowed us to analyze nasal width, mouth width, columella angle, and nostril area. The results demonstrated that there was an increase in arch perimeter and arch length in control and NAM groups in the T2 period in comparison to T1. Labial frenulum angle was reduced in the NAM group compared to the NAM-T1 and control-T2 periods. Treatment with NAM yielded a reduction in nasal width in the period of T2 compared with T1. Columella angle was enhanced after NAM use in T2 and, was different from control group. The nostril area was reduced in the NAM group in T2 compared with control group. Nasoalveolar molding therapy reduced the labial frenulum angle, contributing to a reduction in the extension of the cleft. The NAM protocol improved facial symmetry, mainly through nasal effects, whereas the absence of orthopedic therapy yielded a commitment to the face and maxillary arch symmetry.

The participation of tumor residing pericytes in oral squamous cell carcinoma.

Pericytes are perivascular cells related to vessel structure and angiogenesis that can interact with neoplastic cells, interfering with cancer progression and outcomes. This study focused on the characterization of pericytes in oral squamous cell carcinoma (OSCC) using clinical samples and a transgenic mouse model of oral carcinogenesis. Nestin-/NG2+ (type-1) and nestin+/NG2+ (type-2) pericytes were analyzed by direct fluorescence after induction of oral carcinogenesis (4-nitroquinoline-1-oxide). Gene expression of neuron glial antigen-2 (NG2), platelet-derived growth factor receptor beta (PDGFR-ß), and cluster of differentiation 31 (CD31) was examined in human OSCC tissues. The protein expression of von Willebrand factor and NG2 was assessed in oral leukoplakia (i.e., oral potentially malignant disorders) and OSCC samples. Additionally, clinicopathological aspects and survival data were correlated and validated by bioinformatics using The Cancer Genome Atlas (TCGA). Induction of carcinogenesis in mice produced an increase in both NG2+ pericyte subsets. In human OSCC, advanced-stage tumors showed a significant reduction in CD31 mRNA and von Willebrand factor-positive vessels. Low PDGFR-ß expression was related to a shorter disease-free survival time, while NG2 mRNA overexpression was associated with a reduction in overall survival, consistent with the TCGA data. Herein, oral carcinogenesis resulted in an increase in NG2+ pericytes, which negatively affected survival outcomes.

SOCS2 regulates alveolar bone loss in Aggregatibacter actinomycetemcomitans-induced periodontal disease.

INTRODUCTION: The role of suppressor of cytokine signaling 2 (SOCS2) in Aggregatibacter actinomycetemcomitans (Aa)-induced alveolar bone loss is unknown; thus, it was investigated in this study. METHODS: Alveolar bone loss was induced by infecting C57BL/6 wild-type (WT) and Socs2-knockout (Socs2-/-) mice with Aa. Bone parameters, bone loss, bone cell counts, the expression of bone remodeling markers, and cytokine profile were evaluated by microtomography, histology, qPCR, and/or ELISA. Bone marrow cells (BMC) from WT and Socs2-/- mice were differentiated in osteoblasts or osteoclasts for analysis of the expression of specific markers. RESULTS: Socs2-/- mice intrinsically exhibited irregular phenotypes in the maxillary bone and an increased number of osteoclasts. Upon Aa infection, SOCS2 deficiency resulted in the increased alveolar bone loss, despite decreased proinflammatory cytokine production, in comparison to the WT mice. In vitro, SOCS2 deficiency resulted in the increased osteoclasts formation, decreased expression of bone remodeling markers, and proinflammatory cytokines after Aa-LPS stimulus. CONCLUSIONS: Collectively, data suggest that SOCS2 is a regulator of Aa-induced alveolar bone loss by controlling the differentiation and activity of bone cells, and proinflammatory cytokines availability in the periodontal microenvironment and an important target for new therapeutic strategies. Thus, it can be helpful in preventing alveolar bone loss in periodontal inflammatory conditions.

Release of leachable products from resinous compounds in the saliva of children with anterior open bite treated with spur.

BACKGROUND: To evaluate the release of bisphenol-A glycidyl methacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), bisphenol A (BPA), and phthalates of the composite resin used in the bonding of spurs applied in the treatment of children with anterior open bite and its effects on human keratinocytes. METHODOLOGY: Saliva samples of 22 children were collected before spur attachment (baseline) and 30 minutes (min) and 24 hours (h) after spur bonding. Analysis was performed using high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry (HPLC-MS/MS) and gas chromatography coupled to mass spectrometry (GC-MS). Standardized resin increments were added to three different dilutions of the cell culture medium. Keratinocytes (HaCaT) were cultivated in the conditioned media and evaluated for cell viability (MTT) and cell scratch assay. RESULTS: The levels of BisGMA (1.74±0.27 µg/mL), TEGDMA (2.29±0.36 µg/mL), and BPA (3.264±0.88 µg/L) in the saliva after 30 min, in comparison to baseline (0±0 µg/mL, 0±0 µg/mL, and 1.15±0.21 µg/L, respectively), presented higher numbers. After 24 h, the levels of the monomers were similar to the baseline. Phthalates showed no significant difference among groups. HaCat cells showed increased viability and reduced cell migration over time after exposure to methacrylate-based resin composites. CONCLUSION: Resin composites, used to attach spurs in children with anterior open bite during orthodontic treatment, release monomers after polymerization and can influence the behavior of human keratinocytes, even at very low concentrations. Orthodontists should be aware of the risks of the resinous compounds release and preventive procedures should be held to reduce patient exposure.

A new way of analyzing tooth movement using universal coordinate system geometry single point superposition in a 3D model

ABSTRACT Introduction: Superposing 3D models is an imminent need. However, current methods rely on marking multiple points on the maxilla and mandible, which could increase point marking and overlapping errors. Objective: This study aimed at developing a method for superimposing 3D models of the maxillary and mandibular arches with Autodesk Inventor® engineering software, using a single universal coordinate system (UCS) point superposition. Methods: A total of 104 STL (stereolithography) models of the maxillary and mandibular arches exported from My iTero® platform were retrospectively selected, in which T0 and T1 were the initial and refinement periods, respectively (n=26 per group). The X, Y, and Z coordinates associated with a single point in each arch were inserted into the models with SlicerCMF® software for model orientation. The arch models with UCS registration were transferred to Autodesk Inventor® for superimposition and to measure tooth movements performed during Invisalign® treatment. Arch expansion, intrusion and rotation were analyzed by two examiners. The statistics were performed using intraclass correlation coefficients (ICC), Dahlberg's formula, and t-test (p<0.05). Results: A reliable method of superimposing 3D digital models using a single UCS point in the maxilla and mandible was developed. ICC showed excellent intra- and inter-examiner correlation (ICC>0.90). A systematic error was not found concerning linear and angular measurements (<1mm and <1.5°, respectively). Digital dental movements could be analyzed, including arch expansion, dental intrusion, and tooth rotation. Conclusions: The developed method was proven reliable and reproducible for superimposing 3D models of the maxillary and mandibular arches by using UCS system.

RESUMO Introdução: A sobreposição de modelos 3D é uma necessidade iminente. No entanto, os métodos atuais dependem da marcação de múltiplos pontos na maxila e na mandíbula, o que pode aumentar a incorporação de erros no processo de sobreposição. Objetivo: O objetivo desse estudo foi desenvolver um método para sobrepor modelos 3D das arcadas superior e inferior utilizando o software de engenharia Autodesk Inventor®, por meio da marcação de um único ponto em cada arcada, usando o sistema de coordenadas universal (UCS). Métodos: No total, 104 modelos STL das arcadas superior e inferior exportados da plataforma My iTero® foram selecionados retrospectivamente, onde T0 foi o período inicial e T1, o de refinamento (n=26 por grupo). As coordenadas X, Y e Z associadas a um único ponto em cada arcada foram inseridas nos modelos usando o software SlicerCMF®. Os modelos com os pontos UCS demarcados foram transferidos para o software Autodesk Inventor® para realizar a sobreposição e medir os movimentos dentários realizados durante o tratamento com Invisalign®. Os movimentos de expansão, intrusão e rotação foram analisados por dois examinadores. A análise estatística foi realizada usando os coeficientes de correlação intra-classe (ICC), fórmula de Dahlberg e teste t (p<0,05). Resultados: Foi desenvolvido um método confiável de sobreposição de modelos digitais 3D usando um único ponto UCS na maxila e mandíbula. O ICC apresentou excelente correlação intra e inter-avaliadores (ICC>0,90). Não foi encontrado erro sistemático nas medidas lineares e angulares (<1mm e <1,5°, respectivamente). Os movimentos dentários puderam ser analisados por meio do método proposto, incluindo expansão da arcada, intrusão e rotação dentária. Conclusão: O método desenvolvido provou ser confiável e reprodutível para sobreposição de modelos 3D das arcadas superior e inferior usando o sistema UCS com marcação de ponto único.

Influence of risedronate on orthodontic tooth movement in rodents: a systematic review and case report

ABSTRACT Introduction: Bisphosphonates have an inhibitory impact on osteoclastic activity, reducing bone resorption. However, the influence of risedronate on tooth movement is not well-defined. Objective: This systematic review assessed the effect of risedronate intake on orthodontic tooth movement. A case report was also provided. Methods: Two independent reviewers searched six databases (PubMed, Web of Science, Ovid, Lilacs, Scopus, and Open Grey). The searches were carried out in April/2020, and an update was set in place in June/2023. Therefore, the searches considered a timeline from the databases' inception date until June/2023, with no publication date and/or language restrictions. The clinical question focused on evaluating the orthodontic tooth movement and relapse movement (Outcome) in animals (Population) exposed to risedronate (Exposure), compared to control groups (Comparison). The Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines were applied, and the protocol was registered in PROSPERO (CRD42020168581). The risk of bias was determined using the Systematic Review Centre for Laboratory Animal Experimentation protocol (SYRCLE). Results: Two studies in rats and one in guinea pigs were included in the systematic review. The studies reported a decrease in orthodontic tooth movement, a reduction in the relapse movement, and a reduced number of positive tartrate-resistant acid phosphatase (TRAP) cells, with a significantly reduced number of bone gaps after the administration of risedronate in rats. A case report illustrated the effects of risedronate administration in one patient. Conclusion: Based on the systematic review, risedronate seems to impair orthodontic tooth movement and relapse due to a decrease in bone resorption cells.

RESUMO Introdução: Os bifosfonatos têm um impacto inibitório na atividade osteoclástica, reduzindo a reabsorção óssea. No entanto, a influência do risedronato no movimento dentário não está bem definida. Objetivo: Esta revisão sistemática avaliou o efeito do uso de risedronato no movimento ortodôntico dos dentes. Um relato de caso também é apresentado. Métodos: Dois revisores independentes pesquisaram seis bases de dados (PubMed, Web of Science, Ovid, Lilacs, Scopus e Open Grey), considerando o período de abril de 2020 até junho de 2023, sem restrições de data e/ou idioma de publicação. A questão clínica focou em avaliar o movimento ortodôntico dos dentes e movimento de recidiva (resultado) em animais (população) expostos ao risedronato (exposição) em comparação com grupos de controle (comparação). Foram aplicadas as Diretrizes Preferenciais para Revisão Sistemática e Metanálise (PRISMA) e um protocolo foi registrado no PROSPERO (CRD42020168581). O risco de viés foi determinado utilizando o protocolo do Centro de Revisão Sistemática para Experimentação em Animais de Laboratório (SYRCLE). Resultados: Dois estudos em ratos e um em porquinhos-da-índia foram incluídos na revisão sistemática. Os estudos relataram uma diminuição no movimento ortodôntico dos dentes, uma redução no movimento de recidiva e um número reduzido de células positivas à fosfatase ácida tartarato-resistente (TRAP) com um número significativamente reduzido de falhas ósseas após a administração de risedronato em ratos. Um relato de caso ilustrou os efeitos da administração de risedronato em uma paciente. Conclusão: Com base na revisão sistemática, o risedronato parece interferir no movimento ortodôntico dos dentes e na recidiva devido a uma diminuição nas células de reabsorção óssea.

Indices in dental image exams for bone mineral density evaluation of aromatase inhibitor users.

We evaluated the accuracy of radiomorphometric indices (RI) and fractal dimension (FD) for screening bone mineral density (BMD) in postmenopausal patients who had breast cancer and were using aromatase inhibitors (AI). The sample consisted of 40 participants. Digital panoramic radiography (DPR) and cone beam computed tomography (CBCT) were evaluated along with dual-energy X-ray absorptiometry (DXA), which is the gold standard for detecting low BMD. According to the T-scores of DXA, the subjects were assigned into two groups: with normal BMD and with low BMD (osteopenia and osteoporosis). The area under the curve (AUC), sensitivity, and specificity with their respective confidence intervals were determined for DPR and CBCT. For DPR indices, AUC ranged from 52.6 to 75.8%. The mandibular cortical width (MCW) had the highest AUC. For FD, the total trabecular index had the highest sensitivity, while the index anterior to the mental foramen (MF) had the highest specificity. In CBCT, the AUC ranged from 51.8 to 62.0%. The indices with the highest AUC were the molar (M) and anterior (A). The symphysis (S) index had the highest sensitivity and the posterior (P) index had the highest specificity. Sensitivity and specificity were adequate for the computed tomography index (Inferior; CTI [I]). Therefore, MCW, FD of the mandible angle, and total trabecular ROI in DPR and the CTI (I), M, P, and A indices in CBCT proved to be promising tools in distinguishing individuals with low BMD. Cutoff point for these indices could be a useful tool to investigate low BMD in postmenopausal women taking AI.