Resorptions and orthodontics / Résorptions et orthodontie

Introduction: It's generally accepted that one of the risks associated with orthodontic treatment is apical root resorption, even though this may occur outside orthodontic treatment. In any case, it causes root shortening. Orthodontists are probably the only dental surgeons who use the inflammatory process as a therapeutic tool. They need to be aware of the risk factors for root inflammation. Along with recurrence, leukemia and periodontal problems, resorption is one of the "inconveniences" of orthodontics, which, if not inevitable, must at least be minimized. Material and Method: At present, the orthodontic literature on root resorption provides some clues as to the factors associated with the onset, severity and management of root resorption, although the complexity of this phenomenon does not allow us to arrive at a clear and unequivocal consensus. For this reason, it is important to identify potential risk factors for resorption, to take them into account before/during and after treatment, and to know what attitude to adopt in the event of resorption appearing, all in order to minimize this phenomenon, as everyone agrees that it can be a source of harm and stress for both patient and practitioner. Conclusion: There are still many grey areas in our understanding of the phenomenon, including how the elements of orthodontic treatment influence orthodontic resorption. Irreversible in nature, resorption can be sufficiently extensive to cast doubt on the benefit of successful orthodontic treatment.

Introduction: Il est généralement admis que l'un des risques associés au traitement orthodontique est la résorption radiculaire apicale même si elle peut se produire en dehors de tout traitement orthodontique. Quoi qu'il en soit, elle provoque le raccourcissement radiculaire. Les orthodontistes sont sans doute les seuls spécialistes de la chirurgie dentaire qui utilisent le processus inflammatoire en tant que moyen thérapeutique. Ils doivent connaître les facteurs de risque de cette inflammation sur la racine. La résorption fait partie, au même titre que la récidive, les leucomes et les problèmes parodontaux, des « inconvénients ¼ de l'orthodontie qui, à défaut d'être inévitables, doivent au moins être minimisés. Matériels et méthode: Actuellement, la littérature orthodontique sur la résorption radiculaire fournit quelques pistes sur les facteurs associés à l'apparition, la gravité et la gestion de la résorption radiculaire, même si la complexité de ce phénomène ne nous permet pas d'en dégager un consensus clair et équivoque. Pour cette raison, il est important d'identifier les facteurs de risque de résorption potentiels pour en tenir compte avant/pendant et après le traitement et connaître l'attitude à adopter en cas d'apparition de résorptions, tout ceci afin de minimiser ce phénomène, car tout le monde s'accorde sur le fait qu'elle peut être source de préjudice et de stress pour le patient et le praticien. Conclusion: De nombreuses zones d'ombres subsistent dans la compréhension du phénomène, notamment sur comment les éléments du traitement orthodontique influencent la résorption orthodontique. De nature irréversible, la résorption peut être suffisamment étendue pour jeter un doute sur le bénéfice apporté au succès du traitement orthodontique.

Hypoxic dental pulp stem cells-released succinate promotes osteoclastogenesis and root resorption.

Introduction: Clinical studies have shown that endodontically-treated nonvital teeth exhibit less root resorption during orthodontic tooth movement. The purpose of this study was to explore whether hypoxic dental pulp stem cells (DPSCs) can promote osteoclastogenesis in orthodontically induced inflammatory root resorption (OIIRR). Methods: Succinate in the supernatant of DPSCs under normal and hypoxic conditions was measured by a succinic acid assay kit. The culture supernatant of hypoxia-treated DPSCs was used as conditioned medium (Hypo-CM). Bone marrow-derived macrophages (BMDMs) from succinate receptor 1 (SUCNR1)-knockout or wild-type mice were cultured with conditioned medium (CM), exogenous succinate or a specific inhibitor of SUCNR1 (4c). Tartrate-resistant acid phosphatase (TRAP) staining, Transwell assays, qPCR, Western blotting, and resorption assays were used to evaluate osteoclastogenesis-related changes. Results: The concentration of succinate reached a maximal concentration at 6 h in the supernatant of hypoxia-treated DPSCs. Hypo-CM-treated macrophages were polarized to M1 proinflammatory macrophages. Hypo-CM treatment significantly increased the formation and differentiation of osteoclasts and increased the expression of osteoclastogenesis-related genes, and this effect was inhibited by the specific succinate inhibitor 4c. Succinate promoted chemotaxis and polarization of M1-type macrophages with increased expression of osteoclast generation-related genes. SUCNR1 knockout decreased macrophage migration, M1 macrophage polarization, differentiation and maturation of osteoclasts, as shown by TRAP and NFATc1 expression and cementum resorption. Conclusions: Hypoxic DPSC-derived succinate may promote osteoclast differentiation and root resorption. The regulation of the succinate-SUCNR1 axis may contribute to the reduction in the OIIRR.

[Pulp revascularization procedure for external inflammatory dental root resorption treatment]. / Primenenie metodiki regeneratsii pul'popodobnoi tkani dlya ostanovki naruzhnoi vospalitel'noi rezorbtsii kornya zuba.

THE AIM OF THE STUDY: To assess the effectiveness of pulp revascularization procedure in children with external inflammatory root resorption (EIRR) after constant teeth injury. MATERIALS AND METHOS: The study comprised 17 children aged 6-10 years diagnosed with EIRR as a long-term complication of dental trauma in 19 teeth. EIRR was diagnosed with periapical radiographs and CBCT was performed to further assess the pathology extension. Pulp revascularization was carried out in all 19 teeth. RESULTS: There was no resorption progression in all cases. EIRR areas were substituted by bone. In 10 from 19 teeth with early stages of root development bone or cement-like tissue ingrowth into the root canal was observed radiologically. In cases of severe EIRR this ingrowth may partially compensate for lost tissues which is confirmed by a high percentage (94.7%) of functional teeth during mean follow up time of 38±10 months. CONCLUSION: Pulp revascularization is an effective method for retaining teeth with EIRR for a relatively long period of time and allows maintaining alveolar bone volume both due to functional tooth preservation and healing of bone lesions in periapical and resorption areas.

Full life cycle changes of low impacted mandibular third molar associated cystic lesions and adjacent tooth root resorption: a retrospective study.

OBJECTIVE: Low impacted third molars are usually asymptomatic and are often found by X-ray examination. The removal of asymptomatic low impacted third molars is one of the most controversial clinical issues in oral and maxillofacial surgery. METHODS: In this study, 806 patients with low impacted mandibular third molars (LIMTMs) (full bony impaction) were analyzed to determine the prevalence and risk factors for cystic lesions and adjacent tooth root resorption throughout the patients' entire life cycle. RESULTS: The results showed that the prevalence of adjacent tooth root resorption and cystic lesions was age-related, exhibiting a trend of first increasing and then decreasing; prevalence peaked at the age of 41 to 45 years old, the prevalence rates were 12.50% and 11.11% respectively. And the lowest prevalence rate was 2.86% and 2.44% in ≥ 61 group and 56- to 60-year age group respectively. Age was an independent risk factor for adjacent tooth root resorption of LIMTMs, whereas age and impaction type (especially inverted impaction) were independent risk factors for cystic lesions. CONCLUSIONS: The full life cycle management strategy for LIMTMs may need to be individualized. Surgical removal is recommended for LIMTMs in patients younger than 41 to 45 years, especially for inverted, mesioangular, and horizontally impacted LIMTMs. LIMTMs in patients older than 41 to 45 years may be treated conservatively with regular follow-up, but surgical removal of inverted impacted LIMTMs is still recommended to avoid cyst formation.

Long-term follow-up after the treatment of impacted canines in the maxilla causing severe root resorption of the lateral incisors: two case reports.

BACKGROUND: Root resorption of adjacent teeth due to impacted canines is common, and orthodontic treatment often leads to secondary resorption or even loss of adjacent roots. Clinical reports of long-term stability after treatment are rare. CASE PRESENTATION: This study reports two cases of maxillary impacted canines resulting in severe root resorption of the adjacent lateral incisors. Surgical exposure, orthodontic retraction, and alignment of the impacted canines were successful in both cases, and the resorbed lateral incisors were stable with no significant loosening and normal pulp vitality after treatment and at the 5- and 10-year follow-up appointments. CONCLUSIONS: Light orthodontic force may be used to move adjacent teeth with root resorption due to tooth obstruction. The path and direction in which the teeth are moved must be specifically designed so that the adjacent roots are not resorbed and so long-term stability can be achieved.

Clinical and radiographic characterization of external root resorption. / Características clínicas y radiográficas de reabsorciones radiculares externas.

Introduction: The following bibliographic review was carried out with the purpose of recognizing the clinical and radiographic characteristics that must be considered in the diagnosis of external root resorption, including treatments. Methods: A bibliographic search was carried out in PubMed/Medline, Cochrane Library and Google Scholar databases under the term "external root resorption", from 2010 to 2022 in Spanish and English. Experimental studies and bibliographic reviews were selected, and finally 17 articles were included. Results: The results obtained indicated that each type of resorption presents specific clinical characteristics that differentiate them, these are: for external inflammatory resorption a negative pulp vitality; for replacement external resorption the absence of mobility and metallic percussion; for cervical external resorption a pink coloration of the crown; superficial external resorption does not present any type of clinical symptoms and transient apical collapse presents a transient change in color. Conclusion: External root resorptions require accurate and early diagnosis. A clinical examination should be performed with emphasis on the following: probing, coloration, mobility, and vitality tests.

Introducción: La siguiente revisión bibliográfica se realizó con el propósito de reconocer las características clínicas y radiográficas que deben ser evaluadas para el diagnóstico de las reabsorciones radiculares externas incluyendo también sus tratamientos. Metodología: Se llevó a cabo una búsqueda en las bases de datos MEDLINE/PubMed, Cochrane Library y Google Scholar bajo el término , incluyendo estudios experimentales y revisiones bibliográficas desde 2010 a 2022 en español e inglés, incluyendo finalmente 17 artículos. Resultados: Los resultados obtenidos señalaron que cada tipo de reabsorción radicular externa presenta características clínicas específicas que las diferencian. Estas diferencias son: para la reabsorción externa inflamatoria la vitalidad pulpar negativa; para la reabsorción externa de reemplazo la ausencia de movilidad y percusión metálica; para la reabsorción externa cervical una coloración rosada de la corona; la reabsorción externa superficial no presenta ningún tipo de sintomatología clínica y la reabsorción de colapso apical transitorio presenta un cambio de coloración transitorio. Conclusión: Las reabsorciones radiculares externas requieren un diagnóstico preciso y temprano. Se debe realizar un examen clínico con énfasis en sondaje, coloración, movilidad y pruebas de vitalidad.

Evaluation of the use of a clinical practice guideline for external apical root resorption among orthodontists.

BACKGROUND: External apical root resorption (EARR) is a frequently observed adverse event in patients undergoing fixed appliance therapy. Assessing the patients' risk during treatment is important, as certain factors are assumed to be associated with an increased likelihood of occurrence. However, their predictive value remains limited, making evidence-based clinical decision-making challenging for orthodontists. To address this issue, the Dutch Association of Orthodontists (NvVO) developed a clinical practice guideline (CPG) for EARR in accordance with the AGREE II instrument (Appraisal of Guidelines for Research and Evaluation II) in 2018. The aim of this study is to get insight into the actual utilization and the practical implementation of the guideline among orthodontists. The hypothesis to be tested was that after its introduction, clinical practice for EARR has changed towards the recommendations in the CPG. OBJECTIVE: To investigate the use of the 2018 clinical practice guidelines for EARR among orthodontists 3 years after its introduction. METHODS: A questionnaire using a 7-point Likert scale was developed concerning four domains of EARR described in the guideline. The questionnaire was piloted, finalised, and then distributed digitally among Dutch orthodontists. REDCap was used for data collection, starting with an invitation email in June 2021, followed by two reminders. Effect was tested by the Mann-Whitney U test, and the influence of demographic variables was analysed. RESULTS: Questionnaires were sent out to all 275 and completed by 133 (response rate 48%); N = 59 females and N = 73 males were included; 81% had their training in the Netherlands, 89% had ≥ 6 years of work experience, and 89% worked in private orthodontic practice. One hundred thirty orthodontists (98.5%) reported changes in clinical practice. The biggest positive change in clinical behaviour regarding EARR occurred if EARR was diagnosed during treatment. Sex, clinical experience, country of specialist training, and working environment of the respondents did not affect clinical practices regarding EARR. CONCLUSIONS: This questionnaire demonstrated that, 3 years after introduction of the guideline, orthodontists improved their self-reported clinical practices to a more standardised management of root resorption. None of the demographic predictors had a significant effect on the results.

Clinical and Genetic Analysis of Multiple Idiopathic Cervical Root Resorption.

OBJECTIVE: To explore the genetic background and clinical phenotypes of multiple idiopathic cervical root resorption (MICRR) in a Chinese family. METHODS: The proband and his three family members were clinically examined and had radiographs taken with a radiovisiography (RVG) system and CBCT to define the diagnosis of MICRR. Genomic DNA (gDNA) was extracted from peripheral blood samples of the patient, his father, mother and younger sister for whole exome sequencing (WES). The pathogenicity of rare variants with minor allele frequency (MAF) less than 0.005 were analysed following possible inheritance patterns, predicted results from 12 software programs, the American College of Medical Genetics (ACMG) 2015 criteria, and information from ClinVar, OMIM and HGMD databases as well as gene function. RESULTS: The proband presented the typical MICRR phenotypes such as thin cervical pulp wall and apple core-like lesions in radiographs. Following the recessive inheritance pattern, WES analysis identified SHROOM2, SYTL5, MAGED1 and FLNA with a higher chance of causing MICRR. Four genes with compound heterozygous variants and another 27 genes with de novo variants either in autosomal-dominant or autosomal-recessive pattern were also found to have the potential pathogenicity. CONCLUSION: A total of 35 novel potential pathogenic genes were found to be associated with MICRR from a Chinese family through WES. The new genetic background of MICRR may be helpful for clinical and molecular diagnosis.

Micro-Osteoperforations Accelerate Tooth Movement without Exacerbating the Progression of Root Resorption in Rats.

A recent study reported that micro-osteoperforations (MOPs) accelerated tooth movement by activating alveolar bone remodeling. However, very little is known about the relationship between MOPs and external apical root resorption during orthodontic treatment. In this study, in order to investigate the mechanism through which MOPs accelerate tooth movement without exacerbating the progression of root resorption, we measured the volume of the resorbed root, and performed the terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick-end labeling (TUNEL) method on exposed MOPs during experimental tooth movements in rats. Male Wistar rats (11 weeks old) were divided into three groups: 10 g orthodontic force (optimal force) applied to the maxillary first molar (optimal force: OF group), 50 g orthodontic force application (heavy force: HF group), and 10 g force application plus three small perforations of the cortical plate (OF + MOPs group). On days 1, 4, 7, 10, and 14 after force application, the tooth movement and root volume were investigated by micro-computed tomography. Furthermore, the number of apoptotic cells in the pressured sides of the periodontal ligament (PDL) and surrounding hard tissues were determined by TUNEL staining. The OF + MOPs group exhibited a 1.8-fold increase in tooth movement on days 7, 10, and 14 compared with the OF group. On days 14, the HF group had a higher volume of root loss than the OF and OF + MOPs groups. On the same day, the number of TUNEL-positive cells in the HF group increased at the root (cementum) site whereas that in the OF group increased at the alveolar bone site. Furthermore, the number of TUNEL-positive cells in the OF + MOPs group increased at the alveolar bone site compared with the OF group. These results suggest that MOPs accelerate orthodontic tooth movement without exacerbating the progression of root resorption.

A newly developed kit for dental apical root resorption detection: efficacy and acceptability.

OBJECTIVES: To determine the efficacy of a newly developed kit in dentine sialophosphoprotein (DSPP) detection and compare it with enzyme-linked immunosorbent assay (ELISA). User acceptance was also determined. MATERIALS AND METHODS: This cross-sectional study consisted of 45 subjects who were divided into 3 groups based on the severity of root resorption using radiographs: normal (RO), mild (RM), and severe (RS). DSPP in GCF samples was analyzed using both methods. Questionnaires were distributed to 30 orthodontists to evaluate future user acceptance. RESULTS: The sensitivity and specificity of the kit were 0.98 and 0.8 respectively. The DSPP concentrations measured using ELISA were the highest in the RS group (6.33 ± 0.85 ng/mL) followed by RM group (3.77 ± 0.36 ng/mL) and the RO group had the lowest concentration (2.23 ± 0.55 ng/mL). The new kit portrayed similar results as the ELISA, the optical density (OD) values were the highest in the RS group (0.62 ± 0.10) followed by RM group (0.33 ± 0.03) and the RO group (0.19 ± 0.06). The differences among all the groups were statistically significant (p < 0.05) for both methods. The Pearson correlation coefficient showed a statistically significant (p < 0.001) strong and positive correlation between DSPP concentrations and OD values. CONCLUSIONS: The new kit was validated to detect the colour intensities of different severity of root resorptions. Most of the responses to the survey were positive towards the new kit for being a safer and simpler method to detect apical root resorption.

Influence of alveolar bone thickness and bucco-palatal inclination on root resorption of lateral incisors in unilateral maxillary impacted canines: a retrospective observational study.

BACKGROUND: This study aimed to investigate the potential associations between alveolar bone thickness, bucco-palatal inclination of maxillary lateral incisors, and lateral incisor root resorption in patients with unilateral maxillary impacted canines (UMICs). METHODS: A total of three hundred and five subjects (120 males, 185 females; mean age, 16.39 years; standard deviation, 4.04) with UMICs were included. Canine position and root resorption were assessed using CBCT. UMICs were divided into palatal, buccal and mid-alveolus groups (PICs, BICs and MAICs), with 117, 137 and 51 subjects, respectively. Alveolar bone thickness and bucco-palatal inclination of lateral incisors were measured using the Dolphin software. RESULTS: The prevalence of lateral incisor root resorption was significantly lower in the BICs (13.9%) than MAICs (29.4%) and PICs (29.1%). Alveolar bone thickness of the apical area was smaller in UMICs with lateral incisor root resorption than no resorption in both PICs (8.33 ± 1.64 vs 10.53 ± 2.55 mm) and BICs (8.94 ± 1.85 vs 10.76 ± 2.28 mm). Furthermore, lateral incisors on the impacted side were more buccally inclined in PICs with lateral incisor root resorption than no resorption, while in both BICs and MAICs, there was no statistical difference between lateral incisor root resorption than no resorption. Moreover, alveolar bone thickness of the apical area, rather than bucco-palatal inclination of lateral incisors, was significantly correlated with lateral incisor root resorption both in PICs and BICs. CONCLUSIONS: Lateral incisor root resorption is less common in BICs. Thinner alveolar bone thickness at the apical area of lateral incisors can be considered as a potential risk factor for lateral incisor root resorption in UMICs.

Association of genetic polymorphism of interleukin 1-alpha and interleukin 1-beta with external apical root resorption in orthodontic patients.

OBJECTIVE: To assess the allele rs 1143634 in IL-1ß and rs1800587 in IL-1α in patients for orthodontically induced external apical root resorption (EARR). MATERIAL AND METHODS: Intra-oral periapical radiograph (IOPA) of maxillary incisors of 142 Patients were evaluated for resorption at two time points; before the start of fixed mechanotherapy (T1) and after one year of treatment (T2). The individuals with root resorption<2mm were categorized as a control group (group 1; n=90), and resorption>2mm were categorized as case group (group 2; n=52). Buccal swabs of all patients were taken and DNA could be isolated in 95 out of 142 samples (group 1 {n=58}, group 2 {n=37}), which were then screened for the selected two polymorphic targets to determine the nucleotide status of these targets. Tetra-primer ARMS PCR reactions were carried out using all 4 primers for each polymorphism. RESULTS: rs11800587 was not associated with risk of EARR in any inheritance model. Chi-square test for association of alleles with EARR revealed that rs1143634 was associated with the risk of EARR in an allelic model in such a way that A allele of this SNP increased the risk of EARR 4 folds [OR=4.375; P=0.016]. However, the adjusted level of significance using the Holm-Bonferroni method for rs1143634 was P<0.010 for A and G comparison rendering the results non-significant. CONCLUSION: SNP rs1143634 and SNP rs11800587 were not associated with risk of EARR in any inheritance model.

The effect of fibroblast growth factor-2 on the outcomes of tooth replantation: A systematic review of animal studies.

Background/Aim: The ideal treatment of tooth avulsion is replantation. However, replanting teeth may lead to root resorption. Fibroblast growth factor-2 (FGF-2) is a cytokine that plays an important role in wound repair and tissue regeneration. Recently, FGF-2 has been studied a potential regenerative agent to prevent root resorption and ankylosis. The aim of this review is to analyze and summarize the currently available literature focusing on using FGF-2 based regenerative modalities to improve the outcomes of tooth replantation. Materials and Methods: An electronic search was conducted via PubMed/Medline, Google Scholar and ISI Web of Knowledge, using the Medical Subject Headings (MeSH) terms "Basic fibroblast growth factor," "Fibroblast growth factor-2," "tooth replantation," and "replantation" for studies published between January 2001 and June 2021. Data was extracted and quality assessment was carried using the ARRIVE guidelines. Results: Nine animal studies were included in this review. In six studies, FGF-2 had a favorable effect on the tissue regeneration around roots of replanted teeth when compared to other treatment groups. However, quality assessment of the studies revealed many sources of bias and deficiencies in the studies. Conclusions: Within the limitations of this study, it may be concluded that FGF-2 may improve the outcomes of delayed replantation of avulsed teeth. However, more long-term animal studies, with improved experimental designs, and clinical trials are required to determine the clinical potential of the growth factor in improving the outcomes of delayed tooth replantation.

Factors influencing root resorption in retained mandibular second deciduous molars with congenital absence of second premolars: a cross-sectional study.

BACKGROUND: There are currently no studies that quantitatively compare the relationship of root resorption to the patient's systemic history or craniofacial and intraoral morphology, especially in relation to possible host factors. Thus, this study aimed to clarify the factors associated with root resorption in retained mandibular second deciduous molars with the congenital absence of second premolars and predict the prognosis of retained mandibular second deciduous molars. METHODS: A cohort of 5547 patients who visited the orthodontic clinic at Tokyo Medical and Dental University Dental Hospital between 2013 and 2022 was screened. Lateral cephalometric radiographs, panoramic radiographs, upper and lower dental models, and orthodontic treatment questionnaires were used as reference materials to apply the inclusion and exclusion criteria. Ultimately, 111 patients were included in the analyses. The patients were divided into two groups based on the root resorption levels of the retained mandibular second deciduous molars. Those with less root resorption were classified under the good condition (GC) group, whereas those with more root resorption were classified under the poor condition (PC) group. Demographic, clinical, and cephalometric parameters were compared between the groups. A multivariate logistic regression model was used to predict the probability of root resorption. RESULTS: The prevalence of congenitally missing mandibular second premolars with persistent mandibular second deciduous molars was 2.0%. In a total of 111 patients, eighty-three teeth (53.2%) were classified into the GC group, whereas 73 teeth (46.8%) were classified into the PC group. The Frankfort-mandibular plane angle (FMA) [odds ratio (OR): 0.87], Frankfort-mandibular incisor angle (FMIA) (OR: 0.93), overbite (OR: 1.38), adjacent interdental space (OR: 1.46), distance from occlusal plane (OR: 0.80), and caries treatment (OR: 7.05) were significantly associated with the root resorption of the retained mandibular second deciduous molars. CONCLUSIONS: Our findings suggest that skeletal morphology, oral morphological patterns, and history contribute to root resorption in retained mandibular second deciduous teeth with congenital absence of subsequent permanent teeth.

Role of αENaC in root resorption of adjacent teeth due to entirely impacted mandibular third molars.

BACKGROUND: Entirely impacted mandibular third molar (EIM3M) concerns the pathological external root resorption (ERR) of the adjacent mandibular second molar (M2M) and formation of granulation tissue between two molars. The study aimed to clarify the effect of αENaC, a mechano-sensitive molecule, to explore the mechanical mechanism in this scenario. METHODS: The force EIM3M exerted on M2M was proved by finite element analysis. αENaC expressions were tested by real-time polymerase chain reaction (PCR), immunoblotting and immunofluorescence. Inflammatory and epithelial-mesenchymal transition (EMT)-related molecules expressions were also detected by real-time PCR. The correlation was analyzed by Spearman's correlation analysis, and receiver-operator characteristic (ROC) curve was further exhibited. RESULTS: The force was concentrated in the ERR area. αENaC was upregulated, positively correlated with ERR degree and localized to the fibroblasts in ERR granulation tissues. Moreover, αENaC was respectively and positively associated with elevated TNF-α and N-cadherin in ERR granulation tissues. More importantly, ROC analysis verified αENaC as a novel indication of the incidence of this disease. CONCLUSIONS: Our finding revealed the force from EIM3M causing ERR of M2M, and elucidated the expression and localization of αENaC and its positive correlation with inflammation, EMT and disease severity, suggesting a novel indication in this disease.

The osteoclastic activity in apical distal region of molar mesial roots affects orthodontic tooth movement and root resorption in rats.

The utilization of optimal orthodontic force is crucial to prevent undesirable side effects and ensure efficient tooth movement during orthodontic treatment. However, the sensitivity of existing detection techniques is not sufficient, and the criteria for evaluating optimal force have not been yet established. Here, by employing 3D finite element analysis methodology, we found that the apical distal region (A-D region) of mesial roots is particularly sensitive to orthodontic force in rats. Tartrate-resistant acidic phosphatase (TRAP)-positive osteoclasts began accumulating in the A-D region under the force of 40 grams (g), leading to alveolar bone resorption and tooth movement. When the force reached 80 g, TRAP-positive osteoclasts started appearing on the root surface in the A-D region. Additionally, micro-computed tomography revealed a significant root resorption at 80 g. Notably, the A-D region was identified as a major contributor to whole root resorption. It was determined that 40 g is the minimum effective force for tooth movement with minimal side effects according to the analysis of tooth movement, inclination, and hyalinization. These findings suggest that the A-D region with its changes on the root surface is an important consideration and sensitive indicator when evaluating orthodontic forces for a rat model. Collectively, our investigations into this region would aid in offering valuable implications for preventing and minimizing root resorption during patients' orthodontic treatment.

Introducing a new auto edge detection technique capable of revealing cervical root resorption in CBCT scans with pronounced metallic artifacts.

Cervical resorption is a serious threat to the longevity of the teeth. In this study, the Canny edge-detection algorithm was applied on CBCT images to compare the accuracy of original and Canny views for diagnosing cervical resorption in endodontically treated teeth. Intracanal metallic posts were inserted in 60 extracted teeth being randomly divided into three groups: control, 0.5 mm, and 1 mm cervical resorption. CBCT scans of the teeth were presented to three observers in both original and Canny formats with the accuracy being determined by receiver operating characteristic (ROC) analysis. The DeLong test was used for paired comparisons with the significance level set at 0.05. The highest accuracy belonged to Canny images in 1 mm resorption, followed by Canny images in 0.5 mm resorption, original images in 1 mm resorption, and original images in 0.5 mm resorption, respectively. The Canny images were significantly more accurate in the diagnosis of 0.5 mm (p < 0.001) and 1 mm (p = 0.009) resorption. Application of the Canny edge-detection algorithm could be suggested as a new technique for facilitating the diagnosis of cervical resorption in teeth that are negatively affected by metallic artifacts.

Application of deep learning and feature selection technique on external root resorption identification on CBCT images.

BACKGROUND: Artificial intelligence has been proven to improve the identification of various maxillofacial lesions. The aim of the current study is two-fold: to assess the performance of four deep learning models (DLM) in external root resorption (ERR) identification and to assess the effect of combining feature selection technique (FST) with DLM on their ability in ERR identification. METHODS: External root resorption was simulated on 88 extracted premolar teeth using tungsten bur in different depths (0.5 mm, 1 mm, and 2 mm). All teeth were scanned using a Cone beam CT (Carestream Dental, Atlanta, GA). Afterward, a training (70%), validation (10%), and test (20%) dataset were established. The performance of four DLMs including Random Forest (RF) + Visual Geometry Group 16 (VGG), RF + EfficienNetB4 (EFNET), Support Vector Machine (SVM) + VGG, and SVM + EFNET) and four hybrid models (DLM + FST: (i) FS + RF + VGG, (ii) FS + RF + EFNET, (iii) FS + SVM + VGG and (iv) FS + SVM + EFNET) was compared. Five performance parameters were assessed: classification accuracy, F1-score, precision, specificity, and error rate. FST algorithms (Boruta and Recursive Feature Selection) were combined with the DLMs to assess their performance. RESULTS: RF + VGG exhibited the highest performance in identifying ERR, followed by the other tested models. Similarly, FST combined with RF + VGG outperformed other models with classification accuracy, F1-score, precision, and specificity of 81.9%, weighted accuracy of 83%, and area under the curve (AUC) of 96%. Kruskal Wallis test revealed a significant difference (p = 0.008) in the prediction accuracy among the eight DLMs. CONCLUSION: In general, all DLMs have similar performance on ERR identification. However, the performance can be improved by combining FST with DLMs.

Multiple External Cervical Resorption Lesions in Patient with Graft versus Host Disease Treated with Systemic Bleomycin: A Case Report.

The phenomenon of multiple external cervical root resorption (ECRR) lesions in a single patient is rare but may have a link with the chemotherapeutic agent bleomycin. This case details an adult male with multiple ECRR lesions that developed following chemotherapy. His treatment regimen for Hodgkin's lymphoma included the chemotherapeutic antibiotic bleomycin, which has previously been linked with development of multiple ECRR lesions. The patient developed graft versus host disease following an allogeneic stem cell transplant, which could have a significant role in the development and promotion of the ECRR lesions. In total, 8 teeth developed ECRR, and all the known causative factors were excluded when examined. To our knowledge, this is only the second reported case in the literature to link bleomycin to multiple ECRR lesions. This case report aims to bring the reader's attention to the fact that multiple cervical resorption lesions can develop simultaneously. These lesions can be difficult to diagnose and treat and are often misdiagnosed as caries. Finally, the reader should consider the possible role of bleomycin and graft versus host disease in development of multiple lesions of ECRR.

An evaluation of root resorption associated with the use of photobiomodulation during orthodontic treatment with clear aligners: a retrospective cohort pilot study.

OBJECTIVES: To evaluate the change in tooth root volume using cone-beam computed tomography (CBCT) in a group of patients treated concurrently with clear aligners and an adjunctive photobiomodulation (PBM) device. MATERIALS AND METHODS: This retrospective cohort pilot study included the records of 32 consecutively treated clear aligner patients (23 female, 9 male) from the private practice of one orthodontist. The PBM group (n = 16) used the device once per day for 5 minutes per arch and was compared with a matched control group (n = 16). A semiautomated segmentation technique was used to obtain tooth volume of anterior teeth from CBCT imaging prior to (T0) and during or immediately following (T1) orthodontic treatment with clear aligners. The change in root volume between time points was assessed. RESULTS: There was no statistically significant difference between the pre- and posttreatment root volumes of maxillary and mandibular anterior teeth, regardless of which intervention group the patient belonged to (P > .05). There was also no difference in the mean percentage change in root volume between clear aligner patients in this study who were treated with the PBM device compared with a matched control group (P > .05). CONCLUSIONS: Clear aligner patients in this study who changed their aligners every 3 to 5 days and used adjunctive photobiomodulation therapy did not experience clinically relevant orthodontically induced external root resorption. Due to the small sample size and measurement error in the root segmentation process, the results should be interpreted with caution.