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Introduction: With more dentists performing orthodontics, identifying and managing patients at risk or affected by orthodontically-induced external root resorption (OIERR) is paramount., Methods: This study, conducted according to STROBE (STrengthening the Reporting of OBservational studies in Epidemiology), studied Australian orthodontists. Orthodontists were asked to complete a clinical questionnaire evaluating their diagnostic and management approaches to OIERR., Results: Orthodontists most commonly use a history of previous root resorption and the use of an orthopantomogram to screen and monitor patients. An orthopantomogram is used either 6 months for those identified as at risk of OIERR or 10-12 months for those who are not. Once detected, most orthodontists will record OIERR in terms of severity. If severe root resorption was detected, orthodontists would compromise on the treatment outcome and promptly complete treatment; if extraction sites remain closed, most orthodontists will interrupt treatment for 3-6 months. After treatment, orthodontists' retention protocol is unchanged regardless of OIERR experience. Treatment planning for patients with generalized OIERR before treatment (P = 0.002) was the only decision shown to be associated with years of clinical experience (P >0.05)., Conclusions: It is shown that no 1 method for managing OIERR exists, with most orthodontists arguing patient specificity to treatment modality. The various selected clinical approaches accurately reflect the current state of scientific literature on the topic., (Copyright © 2021 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Objectives: To investigate the prevalence and severity of external apical root resorption (EARR) volumetrically with clear aligner therapy using cone-beam computed tomography (CBCT) as well as determine the possible risk factors and develop a prediction model for EARR., Materials and Methods: In this retrospective study, 320 incisors from 40 Class II patients treated with aligners (Invisalign) were included in this study. CBCT images were obtained at pretreatment (T0) and posttreatment (T1). Root volume was calculated by three-dimensional reconstruction of CBCT images, and apical tooth movement was measured from superimposed CBCT images. Changes in root volume were compared using paired t-tests, and the relationship between root volume loss and potential risk factors was analyzed by multiple linear regression., Results: All of the measured incisors showed root volume loss, with an average of 11.48 ± 6.70 mm3, and the prevalence of severe resorption was 0.625%. The prediction model for EARR included variables of posttreatment sagittal root position (SRP), extraction, tooth type, and apical intrusion and extrusion displacements, with an R2 of 0.51. Age, sex, duration, pretreatment SRP, attachment, advancement, and retraction movements were excluded from the model., Conclusions: Most incisors showed mild to moderate resorption during aligner treatment; only a minimal percentage showed severe resorption. Posttreatment SRP (which showed the highest association with EARR), extraction, tooth type, and apical intrusion and extrusion displacements were risk factors for EARR., (© 2021 by The EH Angle Education and Research Foundation, Inc.)

Root resorption is a common complication during orthodontic treatment. Microcracks occur on the root surface after an orthodontic force is applied and may be related to the root resorption caused by the orthodontic process. However, the mechanisms underlying root resorption induced by microcracks remain unclear. In this study, a rat orthodontic model was used to investigate the biological mechanisms of root resorption caused by microcracks. First, the first molar was loaded with 0.5-N orthodontic force for 7 days, and microcracks were observed on the root apex surface using a scanning electron microscope. Second, to describe the mechanical principle resulting in microcracks, a finite element model of rat orthodontics was established, which showed that a maximum stress on the root apex can cause microcrack extension. Third, after 7 days of loading in vivo, histological observation revealed that root resorption occurred in the stress concentration area and cementoclasts appeared in the resorption cavity. Finally, proteomics analysis of the root apex area, excluding the periodontal ligament, revealed that the NOX2, Aifm1, and MAPK signaling pathways were involved in the root resorption process. Microcrack extension on the root surface increases calcium ion concentrations, alters the proteins related to root resorption, and promotes cementoclast formation., (© 2021. Biomedical Engineering Society.)

Aim: The goal was to investigate interleukin‑1 receptor antagonist (IL-1ra) and dentin sialophosphoprotein (DSPP) levels in gingival crevicular fluid (GCF) as potential biomarkers for orthodontically induced root resorption (OIRR) using enzyme-linked immunosorbent immunoassay (ELISA)., Materials and Methods: In all, 74 subjects were assigned to one of three groups: (1) orthodontic group included orthodontic patients who showed radiographic evidence of 1-3 mm root resorption of a maxillary central incisor, (2) pediatric group included pediatric patients who showed radiographic evidence of physiologic root resorption of a lower second primary molar, and (3) control group included subjects who had no orthodontic treatment and showed no radiographic evidence of root resorption. Samples from the GCF were collected with endodontic absorbent paper points inserted 1 mm below the gingival margin of the tooth. The IL-1ra and DSPP levels were evaluated using ELISA., Results: The IL-1ra levels were 657.5 ± 51.5, 319.9 ± 181.3, and 129.4 ± 54.9 pg/ml for the control, orthodontic, and pediatric groups, respectively. The DSPP levels were 1.6 ± 1.0, 30.1 ± 9.6, and 39.2 ± 3.3 pg/ml for the control, orthodontic, and pediatric groups, respectively. Post hoc analyses revealed significant differences for IL-1ra and DSPP between any two groups. Sensitivity and specificity of IL-1ra for the diagnosis of OIRR showed 80% reliability and a cutoff value of ≤432.6 pg/ml, while the analysis of DSPP showed 100% reliability and a cutoff value of ≥7.33 pg/ml., Conclusions: The levels of IL-1ra and DSPP detected in the orthodontic and pediatric groups indicate a possible association with OIRR. Efforts to develop tests for screening, diagnosis, and monitoring OIRR based on biological markers should continue., (© 2020. Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Objective: The aim was to investigate the effect of mechanical vibration on root resorption with or without orthodontic force application., Material and Methods: Twenty patients who required maxillary premolar extractions as part of orthodontic treatment were randomly divided into two groups of 10: no-force group and force group. Using a split-mouth procedure, each patient's maxillary first premolar teeth were randomly assigned as either vibration or control side for both groups. A buccally directed vibration of 50 Hz, with an Oral-B HummingBird device, was applied to the maxillary first premolar for 10 min/day for 12 weeks. After the force application period, the maxillary first premolars were extracted and scanned with micro-computed tomography. Fiji (ImageJ), performing slice-by-slice quantitative volumetric measurements, was used for resorption crater calculation. Total crater volumes were compared with the Wilcoxon and Mann-Whitney U tests., Results: The total crater volumes in the force and no-force groups were 0.476 mm 3 and 0.017 mm 3 on the vibration side and 0.462 mm 3 and 0.031 mm 3 on the control side, respectively. There was no statistical difference between the vibration and control sides (P > 0.05). There was more resorption by volume in the force group when compared to the no-force group (P < 0.05)., Conclusion: Mechanical vibration did not have a beneficial effect on reducing root resorption; however, force application caused significant root resorption., (© 2021. The Author(s).)

Background and Aims: Systematic reviews (SRs) are considered to provide reliable estimates, but flaws in designs, methods of monitoring effects, and outcomes have the potential to bias results. There are several tools for assessing risk of bias (RoB), most of them designed for SRs of beneficial effects. To our knowledge, there is no tool that is adapted specifically to assess RoB in studies of adverse effects associated with orthodontic treatment. To address this, the aim of this study was first to introduce a tool for assessment of RoB in studies of adverse effects associated with orthodontic treatment and, second, to apply it in an SR of external root resorption (ERR) associated with orthodontic treatment with fixed appliance., Materials and Methods: The approach with domains supported by signalling questions was used for the tool. Domains and signalling questions were tailored to the review questions of the SR of studies of ERR after orthodontic treatment using periapical radiography or cone beam computed tomography. Duplicate study selection, data extraction, and RoB assessment using the tool, followed by meta-analyses, were performed., Results: Using the tool for the assessment of RoB identified shortcomings and report deficiencies of primary studies concerning the presentation of orthodontic treatment, identification of ERR, and analysis of outcomes. RoB assessment resulted in 12 of 32 studies read in full text being included. Reported severe ERR varied across studies between 2 and 14 per cent for all incisors and 10 and 29 per cent for maxillary incisors. Results of ERR related to patients' age and sex, orthodontic diagnosis, and treatment were contradictory. Quality of evidence evaluated by GRADE was low due to study limitations, imprecision, and inconsistency of study results., Conclusions: As the tool and its application highlight important issues to consider when planning, conducting, and reporting research, the tool may have a valuable role for quality enhancement of future studies of outcomes of orthodontic treatment. The tool may also serve for authors when planning SRs. Our SR identified a need for studies that use rigorous methodology and transparent reporting., Registration: PROSPERO (ID = CRD42018084725)., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background/objective: To quantify the expected amount of orthodontically induced root resorption (OIRR) after orthodontic intrusion and assess the treatment-related factors., Search Methods and Eligibility Criteria: Six electronic databases and partial grey literature were searched without limitations regarding language or publication year until April 2020. Randomized clinical trials and non-randomized prospective and retrospective studies evaluating root resorption after orthodontic intrusion were included., Data Collection and Analysis: Risk of bias (RoB) assessment was performed with the Cochrane Collaboration's RoB Tool 2.0 and ROBINS-I tool for the randomized and non-randomized studies, respectively. The data were combined into two random-effects meta-analyses estimating OIRR following orthodontic intrusion. One evaluated OIRR in the anterior region, while the other assessed OIRR in the posterior region. Sub-group analyses regarding the type of mechanics applied, duration of intrusion, amount of force, and sensitivity analysis of the study design and imaging examinations were also performed. The certainty of the evidence was assessed through the Grade of Recommendation, Assessment, Development, and Evaluation (GRADE) approach., Results: The qualitative analysis included 14 studies; however, the meta-analysis was performed with 7 records. The random-effects model assumes that 0.72 mm [95% confidence interval (CI): 0.16 to 1.28] and 0.41 mm (95% CI: -0.24 to 1.07) of OIRR should be expected in the incisors and the molars, respectively. Sub-group analyses showed that the assessed treatment-related factors presented minimum impact in OIRR after orthodontic intrusion. The GRADE resulted in moderate and low certainty regarding the meta-analysis., Limitations: The major limitation of the present meta-analysis is that OIRR can be affected by several factors, some of which are assessed in this review., Conclusions: Orthodontic intrusion, evaluated as an isolated mechanic, caused less than 1 mm of OIRR, which is within the acceptable limits for clinical implication. Treatment-related factors did not show a significant influence on OIRR., Registration: This review was registered in PROSPERO, protocol number CRD42018098495., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To compare the effects of micro-osteoperforations (MOPs) vs piezocision (Piezo) in accelerating orthodontic tooth movement in adults., Setting and Sample Population: In this randomized, single-blinded, parallel-group, split-mouth clinical trial, 24 patients aged 15-40 years were recruited., Subjects and Methods: Patients were randomly allocated into two groups: MOPs and Piezo groups. One side of the maxilla was allocated randomly for treatment with one of these techniques, and the other side was treated conventionally to act as a split-mouth control. The rate of canine retraction was evaluated up to 3 months by three-dimensional digital models using a conventional labial appliance. Root resorption and bone height were evaluated using cone beam computed tomography., Results: The MOPs and Piezo groups showed a significantly higher rate of tooth movement after 3 months on the experimental sides than the control sides. However, the net movements in the MOPs and Piezo groups did not reveal a higher rate of tooth movement. Similarly, the overall net movement was -0.32 ± 1.14 and -0.55 ± 0.89 mm for MOPs and Piezo, respectively (P = .606). Regarding root resorption, the overall changes in intra- or intergroup comparisons were insignificant. Decreased canine palatal bone height was reported on the experimental side of the Piezo group (P = .015) after 3 months, but the overall changes were insignificant., Conclusions: The effect of MOPs and Piezo techniques in accelerating the orthodontic canine retraction was comparable to each other, and to the conventional methods. Neither technique caused root resorption or increased vertical bone loss., (© 2020 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: To evaluate the influence of different image file formats of digital radiographic images on the diagnosis of external (ERR) and internal root resorption (IRR)., Materials and Methods: Thirty-four human teeth were selected. For ERR, 20 teeth were used (10 control and 10 with simulated ERR), and for IRR, 14 teeth were used (before and after IRR simulation). Digital periapical radiographs were acquired using the Digora Toto system and exported in four different image file formats: TIFF, BMP, PNG, and JPEG, totaling 192 radiographs. Five examiners evaluated the images using the JPEGView software and scored the detection of ERR or IRR on a 5-point scale. Sensitivity, specificity, accuracy, and the area under the ROC curve were obtained for the diagnosis of ERR and IRR in the different image file formats. Two-way ANOVA compared the diagnostic values between the file formats and the Kappa test assessed intra- and inter-examiner agreement. The significance level was set at 5% (α = 0.05)., Results: The mean values of intra-examiner agreement were substantial (0.740) for ERR and almost perfect (0.836) for IRR and, inter-examiner was fair (0.263) and moderate (0.421), respectively. No statistically significant differences were found among the different file formats for the diagnostic values of ERR and IRR., Conclusion: The file format of digital radiographs does not influence the diagnosis of ERR and IRR., Clinical Relevance: Digital radiographic images may be susceptible to computational factors; however, they can be stored in multiple file formats without affecting the diagnosis of dental root resorptions., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH, DE part of Springer Nature.)

Introduction: Photoactivated chitosan-based nanoparticles can eliminate bacterial biofilm, inactivate endotoxins, improve resistance to biological degradation (resorption), and promote bone regeneration. This case is the first documentation to highlight the successful healing of teeth with extensive inflammatory root resorption (IRR) with periapical lesions using a combined surgical and nonsurgical root canal therapy using rose bengal functionalized chitosan nanoparticles (CSRBnp)., Methods: A 17-year-old boy with extensive IRR of maxillary right canine (teeth #6), maxillary right lateral incisor (#7), maxillary right central incisor (#8), and maxillary left central incisor (#9) was treated with photoactivated CSRBnp, both intracanal as well as topically on resorptive defects and periapical lesions. The larger external resorptive defects on the root surfaces were restored with Biodentine, whereas the through-and-through periapical lesions were packed with sticky bone for Guided Bone Regeneration., Results: At 26 months of follow-up, the clinical, 2-dimensional (intraoral periapical radiographs) and 3-dimensional (cone-beam computed tomography) images showed absence of clinical symptoms, teeth mobility, arrested IRR, and significant osseous healing of the periradicular region. Postoperatively, the patient retraumatized thrice in relation to #7 resulting in horizontal root fracture, which showed type I pattern of root fracture healing in the follow-up., Conclusions: Photoactivated chitosan-based nanoparticles can be a viable therapeutic option to hinder root resorption while enhancing healing outcomes in cases of severe IRR., (Copyright © 2021 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim and Objective: To carry out comparison of apical root resorption (ARR) in the fixed orthodontic appliance and clear aligners with the help of cone-beam computed tomography (CBCT) imaging., Methods and Materials: The study was conducted on 576 roots in 110 patients. These patients were divided into two groups such that each group consisted of 55 patients. A total of 288 roots were analyzed in each group. One group consisted of patients treated with the conventional fixed orthodontic appliance. Another group consisted of patients treated with clear aligners. Radiographic images were collected with the help of CBCT for each patient. One image was collected before treatment while another image was collected after treatment. The length of the root of the anterior tooth was measured with the help of CBCT images. The ARR was calculated for each tooth by obtaining the difference between the length of the root measured before orthodontic treatment and after orthodontic treatment. The data were recorded, and statistical analysis was carried out with the help of the paired t test and Chi-square test to compare ARR between the two groups., Results: The ARR was more in patients who were treated with fixed orthodontic treatment than in those patients who were treated with clear aligners. The mean value of ARR in fixed orthodontic appliances was 1.51 ± 1.34 mm, whereas the mean value of ARR in clear aligners was 1.12 ± 1.34 mm. The severity of ARR in the clear aligners group (on average) was significantly less than that in the fixed appliances group (on average). It was found that ARR in each individual's tooth included in the study was more in case of the fixed orthodontic appliance as compared with clear aligners ( p <0.001)., Conclusion: From the present study, it can be concluded that the amount of resorption at the root apex is less among patients who undergo treatment using clear aligners as compared with those treated with conventional fixed orthodontics appliances., Clinical Significance: ARR found in the orthodontic treatment is a process that causes loss of hard dental tissues such as dentine and cementum at the root apex. Fixed orthodontic appliances are most common method of orthodontic treatment. However, clear aligners are also used commonly for orthodontic treatment.

Objectives: To assess the impact of orthodontic treatment combined with piezocision (OT-PC) on root structure and alveolar bone., Materials and Methods: Twelve adults were treated with OT-PC. Pre- and post-treatment CBCT examinations evaluated apical root resorption (ARR) and alveolar bone height and thickness changes. Pre- and post-treatment differences were compared using one-sample t test and Wilcoxon signed-rank test., Results: ARRs were generalized and significantly more severe in both anterior sextants compared with posterior sextants. Bone thickness decreased significantly in the maxilla at mid-root and apex areas. The majority of mandibular alveolar bone dehiscences occurred on the buccal aspect at the mid-root level, especially where thickness was less than 0.3 mm. Overall bone height decreased twice as much on the buccal aspect (1.43 mm, P < 0.001) compared with the lingual aspect (0.67 mm, P = 0.001), most significantly in the lower incisors, where the average median loss was 2.10 mm (P = 0.003)., Conclusion: OT-PC causes minor negative effects on both alveolar bone and root resorption., Clinical Relevance: Orthodontic treatment combined with piezocision causes minor negative effects on periodontal support. Nevertheless, mild bone height loss on the buccal aspect of the mandibular teeth and root resorption in both anterior sextants have been detected with this new treatment., (© 2020. Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: The current study investigated the correlation between pulpal sensitivity to the electric pulp tester (EPT) and external apical root resorption (EARR) in four types of maxillary anterior teeth of fixed orthodontic treatment patients., Methods: In this prospective cohort study, 232 anterior teeth of 58 patients (mean age 18.96 ± 6.13 years) treated with fixed orthodontic treatment were examined. The EPT readings were recorded at twelve time points immediately before archwire insertion. Root resorption of four maxillary incisors were measured by means of parallel periapical radiographs at three time intervals (six months interval from the start) through design-to-purpose software to optimize data collection. A multiple linear regression model and Pearson correlation coefficient were used to assess the association of EPT values and observed EARR (p< 0.05)., Results: The highest level of EPT measurement was recorded at initial visit, and then there was a decreasing trend in EPT level during treatment for the next six and twelve months. There was another increasing trend after six months till the finishing time of the treatment. There was a significant correlation between changes in root length and time of recording the root length (p< 0.001). There was significant positive correlation between changes in EPT level and amount of observed root resorption (p< 0.001)., Conclusion: The relative decrease in electric pulp test level could be a diagnostic sign of root resorption during orthodontic treatment. Further studies with longer follow up are needed to confirm the current results.

This study aimed to investigate the effects of low-intensity pulsed ultrasound (LIPUS) on replacement root resorption after replantation of avulsed teeth stored in a dry condition in dogs. A total of 73 premolar roots from four male mongrel dogs were intentionally avulsed with forceps and divided into four groups-HN, HL, DN, and DL-according to storage conditions and whether or not they received LIPUS treatment. Thirty-eight roots were kept in Hanks' Balanced Salt Solution for 30 min (HN and HL groups), whereas the remaining 35 roots were left to dry in the air for an hour (DN and DL groups) prior to replantation. Following replantation, the roots in the HL and DL groups (21 and 18 roots, respectively) received a 20-min daily LIPUS treatment for 2 weeks. The animals were euthanized 4 weeks after the operation. Micro-computed tomography images were acquired for each root and the amount of replacement root resorption was measured three-dimensionally. Histological assessments were also carried out. There was significantly less replacement root resorption for the roots in the DL group compared to the DN group (p < 0.01). Histological findings in the DN group demonstrated evident replacement root resorption, whereas the DL group revealed less severe resorption compared to the DN group. Within the limitations, these results suggest that LIPUS could attenuate the replacement resorption of avulsed teeth stored in a dry condition, thereby improving their prognosis.

External cervical resorption (ECR) is a relatively uncommon yet aggressive form of dental hard tissue destruction. It is initiated at the cervical aspect of the root surface and extends apicocoronally and circumferentially inside the dentin. Despite the large number of case reports and clinical studies that have investigated ECR, its etiology remains unclear. Recent advancements in clinical assessment measures, such as the use of cone-beam computed tomographic imaging, have provided additional insights into the nature of this lesion. This has facilitated the continued development and improvement of treatment methods for this condition. In this article, we provide an overview of the latest research pertaining to the etiology, histopathology, predisposing factors, diagnosis, classification, and treatment of ECR. Furthermore, we provide a summary of the different classification schemes for ECR and highlight the relevant therapeutic principles., (Copyright © 2021 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: The objective of the study was to compare external root resorption during orthodontic tooth movement between patients who were subjected to photobiomodulation and those who were not., Materials and Methods: The study was designed as a split-mouth, single-blind randomized controlled trial conducted on twenty-two orthodontic patients requiring extraction of maxillary first premolars (age group 13-30years). A buccal force was applied to all the premolars using a 0.019″×0.025″ beta-titanium cantilever spring for 28days. The test group premolars were irradiated by indium-gallium-arsenide (InGaAs) diode laser (980nm, 100mW) 0, 3, 7, 11, 15 and 28days after force application. Each premolar was irradiated at ten locations on the buccal and palatal gingiva resulting in a total energy of 10J delivered per tooth. After 28days, the root surface of all the premolars were studied for the number and volume of resorption craters using three-dimensional optical profilometry by a blinded assessor. One-sample Kolmogorov-Smirnov test was used to ascertain normality and Mann-Whitney U test was applied for data analysis., Results: All twenty-two patients enrolled completed the study. The root surface analysis showed formation of 32.78% less number of resorption craters (P<0.05) and 39.49% less volume of resorption craters (P<0.05) in the test group premolars relative to the control group premolars., Conclusions: The results of the present study, therefore, suggest that photobiomodulation reduces external root resorption during orthodontic tooth movement., Trial Registration/registration Number: CTRI/2018/04/013520., (Copyright © 2021 CEO. Published by Elsevier Masson SAS. All rights reserved.)

Maxillary and mandibular incisors have increased risk for severe orthodontically induced inflammatory root resorption. A patient-related risk factor is aberrant root morphology. This study aimed to assess the frequency of detection of different root morphologies in anterior teeth using dental panoramic tomography (DPT) and long cone periapical radiographs (LCPAs). A retrospective cross-sectional design was used to assess a sample of 50 consecutive pre-treatment radiographic records of patients from a specialist orthodontic practice in Adelaide, Australia. A reference guide was developed that included three previously unreported morphologies: pipette and bent, bent and pointed, bent and blunt. Two trained and calibrated assessors examined each record against the inclusion criteria, then independently assessed each anterior tooth from DPTs and LCPAs to detect the type of root morphology present. Data were analysed using the chi-square statistical test. Radiographic records for 48 patients (48 DPTs and 161 LCPAs) were eligible, with 355 and 426 teeth on DPTs and LCPAs, respectively, included for assessment. Normal root morphology (119 teeth) was commonly observed in DPTs, while bent (154 teeth) was frequently observed using LCPAs. Mandibular incisors often had normal morphology in DPTs but bent in LCPAs. Bent was the most common morphology in maxillary lateral incisors using DPT and LCPAs, although maxillary centrals were mostly normal in DPTs but pointed in LCPAs. Differences using the two image acquisition methods were highly significant (p < 0.01). Aberrant root morphologies are more easily detected in anterior teeth using LCPAs compared to DPTs.

Aim: This case aims to detail intentional replantation as a last resort to save an otherwise hopeless premolar with perforated internal resorption and root fracture., Background: Internal root resorption, progressive destruction of intraradicular dentin, is a condition that sometimes renders a tooth non-restorable. In the rare cases reported where severe internal resorption leads to root fracture, extraction of the tooth seemed to be a common treatment of choice, and a few literatures had reported endodontic surgery as an alternative treatment option. To date, there had been no report of treating internal root resorption using intentional replantation., Case Description: A 20-year-old male presented swelling at the buccal region of his left maxillary second premolar (#13). Clinical examination revealed a sinus tract and fractured dens evaginatus at the occlusal surface of the tooth. Radiographically, a large area of radiolucency was detected within the middle third of the root, where root fracture was present, leaving a triangular-shaped mature root apex. The condition was diagnosed as internal root resorption and root fracture. Endodontic surgery was excluded from treatment choices due to potential damage of periodontal bone. Instead, intentional replantation was performed, with the application of biomaterials including mineral trioxide aggregate (MTA) and platelet-rich fibrin (L-PRF). The tooth achieved satisfactory healing and remained asymptomatic after 2 years of follow-up., Conclusion: The successful outcome of the case suggests that intentional replantation could preserve a fractured tooth caused by internal root resorption. Incorporated application of biomaterials, such as MTA and L-PRF, might as well improve the chances of saving this otherwise hopeless tooth., Clinical Significance: Through careful planning and execution, intentional replantation is a viable alternative treatment option to preserve a fractured tooth caused by internal root resorption, while leaving periodontal bone architecture almost intact. How to cite this article: Yang Y, Zhang B, Huang C, et al. Intentional Replantation of a Second Premolar with Internal Resorption and Root Fracture: A Case Report. J Contemp Dent Pract 2021;22(5):562-567.

Objectives: To evaluate the volume, amount, and localization of root resorption in the upper first premolars by micro-computed tomography (micro-CT) after three different rapid maxillary expansion appliances and two different activation rhythms., Materials and Methods: The patients were divided into three groups; Hyrax, acrylic cap splint (ACS), and full coverage acrylic bonded (FCAB) appliances. Each group was then divided into the following two subgroups: rapid maxillary expansion (RME) and semirapid maxillary expansion (SRME). After expansion was completed, the appliances were stabilized for 12 weeks during the retention period. For each group, 10 premolars (for a total of 60 premolars) were scanned with the micro-CT (SkyScan). The reconstructed 3D images of each root sample were divided into six regions. The resorption craters on these six different root surfaces were analyzed by special CTAn (SkyScan) software for direct volumetric measurements. Kruskal-Wallis one-way analysis of variance and Mann-Whitney U tests were used for statistical analysis., Results: The total volume of root resorption was less with FCAB than with ACS and Hyrax (P < .001). In all groups, a greater volume of resorption was found on the buccal surface than on the lingual surface (P < .001). No significant differences were found between the RME and SRME groups (P > .05)., Conclusions: All expansion appliances caused root resorption in the upper first premolar teeth, but FCAB may be safer in terms of root resorption. The resorption craters were generally concentrated on the buccal surface. There was no effect of activation rhythm on root resorption., (© 2021 by The EH Angle Education and Research Foundation, Inc.)

Objective: This study aimed to compare the amounts of external root resorption (ERR) during different modalities of orthodontic treatment (OT) in root-filled teeth (RFT) and their contralateral teeth with vital pulp (VPT) in the same patient., Material and Methods: The study sample consisted of 69 patients in two groups: 35 patients in the non-extraction group (18 female, 17 male; 18.16 ± 3.79 years), and 34 patients in the extraction group (19 female, 15 male; 17.72 ± 2.78 years). Digital panoramic radiographs of each patient taken before and after OT were used to measure the tooth length and root surface area. The amounts of ERR in RFT and contralateral VPT were evaluated pre- and post-OT in mandibular molars. The data were statistically analyzed with the paired t -test, independent t -test, and analysis of covariance (ANCOVA) ( p  < .05)., Results: A statistically significant difference was observed in both the orthodontic treatment groups when RFT and VPT were compared in terms of ERR ( p  < .05). A significant difference was observed between RFT and VPT in extraction treatments when the reduction in the root area between the two sides in the groups was compared ( p  < .05)., Conclusions: RFT are more resistant to ERR than VPT. The ERR in RFT may not be a significant matter for the planning of OT.

Objectives: The aim of this retrospective study was to determine the position of the impacted maxillary canine (IMC) and then to inspect the frequency, location, and extent of the consequent root resorption (RR) of the adjacent teeth by using CBCT., Materials and Methods: Forty-one patients aged 12-68 who have 56 IMC detected on CBCT images were retrospectively examined in 3D. The canine position was determined by assessing the side of impaction, buccopalatal location, the distance of the canine cusp tip to the midline and to the occlusal plane, and canine angulation to the midline. RR of adjacent teeth was analyzed by investigating the nearest location of ectopic canine to adjacent teeth in horizontal and vertical dimensions in addition to measuring the degree of RR., Results: Twenty-seven (48.2%) impacted canines were on the right side, and 29 (51.8%) were on the left. Most of these teeth 31 (55.4%) were located palatally, while buccal impaction was seen in only 13 (23.2%) canines and 12 (21.4%) were located centrally. The mean distance of the ectopic canine cusp tip to the occlusal plane was significantly higher in males (14.4 mm) than in females (10.7 mm). RR was seen in 9 central incisors (31.03%) and 21 lateral incisors (41.17%) as well as one case in the first and second premolar. This RR was slight for all the adjacent central incisors and premolars., Conclusions: IMC is more frequent in females, palatally and apically. When left untreated, it may cause RR of some of the adjacent teeth with various degrees, however, with no gender preference., Competing Interests: The authors declare no conflict of interest., (Copyright © 2021 Israa Hussein Ali et al.)

Purpose: To compare apical root resorption of maxillary incisors between adolescents and adults after orthodontic treatment., Methods: Patients receiving orthodontic treatment in Affiliated Hospital of Chifeng University from May 2014 to August 2016 were enrolled, and divided into two age groups: adolescent group (32) and adult group (36). The included subjects received orthodontic fixed appliance treatment with straight-wire technique combined with Hawley type retainer for one year. After treatment, all patients were followed up for one year. Then the apical root resorption of maxillary incisors was evaluated by cone-beam CT (CBCT) at 4 time points, including pre-treatment (T1), end of treatment (T2), 6 months after treatment (T3), and 12 months after treatment (T4). Data were processed by SPSS 20.0 software package., Results: The external root volume of maxillary central incisor, lateral incisors, mandibular central incisors and mandibular lateral incisors of both sides at T2-T4 was significantly lower than that at T1(P<0.05). There was partial increase in root volume of both groups at T3 and T4, while no significant difference from that at T2 (P>0.05). △root volume T3-T2 and △root volume T4-T3 had no significant difference between the two groups (P>0.05). △root volume T3-T2 in the adolescent group was significantly smaller than that in the adult group (P<0.05). Correlation analysis showed that the △root volumeT1-T2 was significantly positively correlated with age (P<0.05), meanwhile △root volume T3-T2 and △root volume T4-T3 were negatively correlated with age (P<0.05)., Conclusions: Age is an important factor affecting the volume of root after orthodontic treatment. Adolescent patients with Class II division 1 malocclusion have a strong ability of self-healing after orthodontic treatment.

Background: The role of injectable platelet rich fibrin (i-PRF) in orthodontic treatment has not been investigated with focus on its effect on dental and bony periodontal elements., Objective: To evaluate the efficacy of i-PRF in bone preservation and prevention of root resorption., Methods: A randomized split-mouth controlled trial included 21 patients aged 16-28 years (20.85 ± 3.85), who were treated for Class II malocclusion with the extraction of the maxillary first premolars. Right and left sides were randomly allocated to either experimental treated with i-PRF or control sides. After the leveling and alignment phase, the canines were retracted with 150gm forces. The i-PRF was prepared from the blood of each patient following a precise protocol, then injected immediately before canine retraction on the buccal and palatal aspects of the extraction sites. Localized maxillary cone beam computed tomography scans were taken before and after canine retraction to measure alveolar bone height and thickness and canine root length (indicative of root resorption), and the presence of dehiscence and fenestration. Paired sample t-tests and Wilcoxon signed rank tests were used to compare the changes between groups., Results: No statistically significant differences in bone height, bone thickness were found between sides and between pre- and post-retraction period. However, root length was reduced post retraction but did not differ between sides. In both groups, postoperative dehiscence was observed buccally and palatally and fenestrations were recorded on only the buccal aspect., Conclusions: I-PRF did not affect bone quality during canine retraction or prevent canine root resorption. I-PRF did not reduce the prevalence of dehiscence and fenestration. Trial registration ClinicalTrials.gov (identifier number: NCT03399760. 16/01/2018).

Introduction: The objective of this research was to investigate the effects of different wavelengths low-level laser therapies on orthodontically induced inflammatory root resorption (OIIRR) during orthodontic tooth movement in rats by micro-computerized tomography., Methods: Forty Wistar albino rats were divided into 5 groups: control group (A), 405-nm laser group (B), 532-nm laser group (C), 650-nm laser group (D), and 940-nm laser group (E). The left side of group A was used as a positive control (A-PC), and the right side of group A was used as a negative control (A-NC) group. In all groups, the maxillary left first molars were moved mesially by 50 g of force for 14 days. The lasers were performed for 9 minutes on the maxillary left first molar tooth. At the end of the experimental period, OIIRR measurements were performed at the mesial and the distal sides along the mesial root of the maxillary first molars., Results: The root resorption volume was significantly lower in group A-NC than in groups A-PC, B, and D. The percentage of root resorption was significantly lower in group A-NC than in all other groups. The root resorption volume and the percentage of root resorption in groups C, D, and E were significantly lower than group A-PC. The depth and the width of the lacuna and even the number of mesial lacunae were similar between groups. The distal and the total lacunae were significantly lower in group A-NC than in all other groups except group C., Conclusions: The 532-nm, 650-nm, and 940-nm lasers significantly reduced the volume of OIIRR. In addition, the 532-nm laser reduced the number of lacunae both distally and totally than all the other groups., (Copyright © 2020 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: The objectives were to visualize the incisive canal (IC) remodelling following maximum incisor retraction and to evaluate its impact on canal-invasion-associated apical root resorption., Methods: Pre- and post-treatment CBCT images of 34 adult orthodontic patients (age 18-47 years) with a large amount of maxillary incisor retraction (>4 mm) using temporary anchorage devices (TADs) were retrospectively evaluated. Maxillary regional superimpositions and 3D models of the IC along with central incisors were used to measure the changes in IC dimension, IC invasion by the roots and IC remodelling. In addition, the association of the amount of apical root resorption with the root-IC relationship and IC remodelling were evaluated., Results: IC invasion by the incisor roots following maximum retraction was seen in 53% (18 out of 34) of the cases. IC with larger volume and area showed more invasions compared with those with smaller volume and area (P < .01). The amount of root resorption was significantly higher with IC invasion than without invasion (2.39 mm vs 0.82 mm, P < .0001). IC remodelling following maximum retraction was seen in 24% of the subjects. IC remodelling group demonstrated less apical root resorption than the non-remodelling group (0.98 mm vs 3.27 mm, P < .0001)., Conclusion: IC with larger volume and surface area before treatment were more likely to show canal invasion by the incisor roots after maximum retraction. IC invasion resulted in apical root resorption. However, approximately one-fourth of cases showed remodelling of the IC, which reduced the amount of root resorption., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Aim: This report presents a case of external cervical resorption and illustrates the effects of a non-surgical approach in the amelioration of this condition and discusses the etiology, classifications, and treatment options., Background: One of the most common root resorption forms is external cervical resorption, which initiates in the cervical area of the tooth and spreads out in the thickness of the dentin in an irregular way. This resorptive process may spread across the dentin leading to significant loss of tooth structure, with or without pulp involvement., Case Description: During a routine radiographic examination of a 25-year-old female patient, external cervical resorption in a maxillary right second premolar was discovered. Cone-beam computed tomography (CBCT) confirmed the extension of the lesion into the pulp and the need for root canal treatment. The defect was sealed with bioceramic putty. One year CBCT follow-up demonstrated the cessation of the resorption site with no clinical symptoms., Conclusion: CBCT examination and combining non-surgical root canal treatment with non-surgical repair using bioceramic putty was an effective treatment option., Clinical Significance: Treatment selection of external cervical resorption depends on many factors, including the location and severity of the resorptive defect and the remaining tooth structure. If the resorptive defect has extended to the pulp, the management involves root canal treatment and subsequent placement of a direct restoration to restore the resorptive lesion.

Objective: The aim of this study was to describe the occurrence, angulation and mesialisation ratio of the ectopic eruption of the maxillary permanent first molar (PFM) and its correlation with the pathological resorption of maxillary primary second molar (PSM)., Methods: This retrospective study was performed using the subsequent panoramic radiographs of 11.924 child patients aged 6-10 years. Ectopic eruption status is categorised as self-corrected and impacted types. To evaluate the differences between the two groups (self-corrected and impacted), the angulation of PFM, mesialisation ratio of PFM, and degree of adjacent PSM root resorption were also assessed. The data were statistically analysed using ANOVA and chi-square tests. Pearson correlation was used to analyse whether a quantitative relationship exists between PFM mesialisation ratio and PSM root resorption., Results: Ectopic eruption frequency was determined as 0.83%. The distribution of ectopic eruption according to gender shows a higher prevalence in males than females. In most cases of ectopic eruption, the eruption status was impacted. The impacted PFMs showed more negative vertical and positive horizontal angle between the PSM and PFM. There was no significant difference between eruption status and angles. Mesialisation ratio of impacted PFMs was significantly higher than self-corrected PFMs. There was significant difference between the PFM mesialisation ratio and the degree of PSM root resorption., Conclusion: Even if eruption disturbances do not occur frequently, making an early diagnosis is important to begin treatment at an optimal time. Although the relationship between horizontal and vertical angles and the ectopic eruption pattern is controversial, it is one of the clinical determinants. The mesialisation ratio of the impacted type was significantly higher than the self-corrected type. Self-correction of PFM was reduced in PSM with grade III and IV root resorption., (© 2020 John Wiley & Sons Ltd.)

Background: Orthodontic root resorptions are frequently investigated in small animals, and micro-computed tomography (μCT) enables volumetric comparison. Despite, due to overlapping histograms from dentine and bone, accurate quantification of root resorption is challenging. The present study aims at (i) validating a novel automated approach for tooth segmentation (ATS), (ii) to indicate that matching of contralateral teeth is eligible to assess orthodontic tooth movement (OTM) and root resorption (RR), (iii) and to apply the novel approach in an animal trial performing orthodontic tooth movement., Methods: The oral apparatus of three female mice were scanned with a μCT. The first molars of each jaw and animal were segmented using ATS (test) and manually (control), and contralateral volumes were compared. Agreement in root volumes and time efficiency were assessed for method validation. In another n = 14 animals, the left first upper molar was protracted for 11 days at 0.5 N, whereas the contralateral molar served as control. Following ATS, OTM and RR were estimated., Results: ATS was significantly more time efficient compared to the manual approach (81% faster, P < 0.01), accurate (volume differences: - 0.01 ± 0.04 mm 3 ), and contralateral roots had comparable volumes. Protracted molars had significantly lower root volumes (P = 0.03), whereas the amount of OTM failed to reveal linear association with RR (P > 0.05)., Conclusions: Within the limits of the study, it was demonstrated that the combination of ATS and registration of contralateral jaws enables measurements of OTS and associated RR in μCT scans.

Aim: The objective of this case report was to present a rare case of simultaneous multiple internal root resorption (IRR) in four mandibular incisors and discuss the possible etiology and suitable armamentarium for its treatment based on different morphological considerations., Background: IRR in permanent dentition is a rare pathological condition and its etiology is not yet fully understood. Very few cases of multiple IRR were reported. This is the first reported case of multiple IRR due to traumatic injury., Case Description: A 23-year-old man suffered trauma to his mandible after falling from a trampoline. His mandibular incisors suffered subluxation injuries and his orthodontic fixed retainer got detached. He delayed treatment and visited our clinic 4.5 months after the incident. Clinical and radiographic examination revealed four mandibular incisors with almost identical IRR defects at the apical third of the roots. The patient was then treated with four non-surgical root canal treatments using various endodontic instruments and techniques. Fifteen-month post-trauma, he showed no evidence of pathology at the follow-up examination., Conclusion: Delayed treatment of dental trauma might cause multiple IRR, and the presence of an orthodontic fixed retainer can distribute surface forces and result in uniform IRR defects., Clinical Significance: The combination of the self-adjusting file (SAF) and the XP-endo finisher is recommended for chemomechanical preparation of IRR defects in oval canals, especially at the apical third.

Objective: The aim of this study was to evaluate and compare the amount of external apical root resorption (EARR) observed during the orthodontic treatment with pre-adjusted edgewise appliance (PEA) or clear aligner therapy (CAT) and with 2D or 3D radiographic methods of measuring the root resorption., Search Strategy and Selection Criteria: A search of PubMed MEDLINE, Scopus, Cochrane Central Register of Controlled Trials, LILACS, Web of Science, Dissertations & Theses Global, ClinicalTrials.gov registry, and the ISRCTN Registry was performed. Studies that have evaluated the amount of root resorption in non-extraction cases using CAT or PEA were selected for the systematic review. A meta-analysis was performed for the amount of root resorption of permanent maxillary incisors using PEA or CAT treatment modalities by either 2D or cone-beam computed tomography radiographic examination., Data Collection and Analysis: Database research, elimination of duplicate studies, data extraction, and risk of bias were performed by authors independently and in duplication. A random-effect meta-analysis followed by subgroup comparisons were performed to evaluate EARR., Results: A total of 16 studies (4 were prospective and 12 were retrospective) were identified for inclusion in the systematic review. The mean root resorption for the permanent maxillary incisors was in the range from 0.25 to 1.13 mm (overall: 0.49 mm; 95% confidence interval [CI] = 0.24 to 0.75 mm). The mean root resorption difference between CAT and PEA was statistically significant (P < 0.05) for 12 but not for 21, 11, or 22., Limitations: One of the drawbacks is a lack of good quality prospective studies, specifically randomized clinical trials in the literature., Conclusions and Implications: Neither PEA or CAT technique leads to clinically significant root resorption (1 mm) of the maxillary incisors. The amount of EARR of maxillary incisors is not significant in comparing two treatment modalities (PEA and CAT), except for 12, where the PEA group has significantly more EARR when compared to CAT., Registration: The protocol for this systematic review was based on the Cochrane Handbook for Systematic Reviews of Interventions 5.1.0 and was registered at PROSPERO database (https://www.crd.york.ac.uk/prospero/display&#95;record.php?ID=CRD42018113051). This systematic review is reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement., (© The Author(s) 2020. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Objective: To assess the frequency of maxillary ectopic canine both buccally and palatally displaced with incisor root resorption and dental agenesis., Methods: The cross-sectional study was conducted from April 8 to June 29, 2019, at the Department of Orthodontics, Dr. Ishrat Ul Ebad Khan Institute of Oral Health Sciences, and Dow Dental College, Dow University Of Health Sciences, Karachi, and comprised orthodontic patients diagnosed with maxillary ectopic canine eruption. Root resorption and agenesis were diagnosed on panoramic films. Root resorption was further confirmed by periapical radiographs. Data was analysed using SPSS 21., Results: Of the 98 subjects, 86(87.8%) had buccally displaced canines of which 38(44.2%) were associated with root resorption, while 12(12.2%) patients had palatally displaced canines of which 10(83.3%) had root resorption (p=0.011). Overall, 30(30.6%) lateral incisors were resorbed, 7(7.1%) both central and lateral incisors, 5(5.1%) premolars, and 6(6.1%) both lateral incisors and premolars were resorbed. Agenesis was detected in 10 (10.2%) subjects (p=0.62)., Conclusions: There was found to be no association of maxillary ectopic canines with incisor root resorption and dental agenesis.

The aim of this case report was to present a reparative treatment approach of an extensive internal inflammatory resorption with a lateral perforation and apical and lateral inflammatory lesions. Only the necrotic coronal part of the pulp was removed, and the vital pulp tissue within the resorption cavity and the apical part of the root canal was left uninstrumented. Bleeding was induced, and the blood clot was covered with mineral trioxide aggregate. Hard tissue repair and healing of the apical lesion could be observed in the 3-year recall., (Copyright © 2020 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: The amount of apical root resorption when using the torque-segmented archwire (TSA) was investigated as well as the extent and direction of the therapeutically indicated apical movement and the treatment duration., Materials and Methods: The degree of apical root resorption in 18 randomly chosen Class II and Class I patients treated with the TSA, as well as in 18 conventionally treated patients were evaluated using pre- and posttreatment panoramic radiographs. The sagittal and vertical apical movements and inclination changes were determined based on pre- and posttreatment lateral cephalograms. Nonparametric tests were applied to test between treatment groups and steps. The Mann-Whitney U test, Kruskal-Wallis, Pearson correlation and Wilcoxon signed-rank test were applied for statistical analysis (p < 0.05)., Results: The incidence of root resorptions was 89-94.4% in low or moderate level. The relative root-crown ratio (rRCR) was not statistically different between the TSA and control groups except tooth 12. The axis of the incisors in the TSA group was significantly improved. The main direction of movement of the apices of the central incisors was retrusion and extrusion. No interdependence between the amount of resorption and the parameters of treatment duration, extent and direction of apical movement were found., Conclusion: The results of the study showed that the amount of apical root resorption with the TSA is slight to moderate and can be compared to conventional orthodontic treatment. The TSA is hence a suitable method for applying targeted torques to the incisors.

External root resorption (ERR) is often a complication of traumatic injury to the teeth. Traditionally, external inflammatory root resorption is treated with calcium hydroxide. The outcome of ERR, especially replacement resorption, is unpredictable. The purpose of the present case report was to describe regenerative endodontic procedures (REPs) for 1 replanted avulsed tooth with severe external root resorption and root perforation (tooth #9) and 1 extruded tooth (tooth #8). A 9-year-old girl was referred for the treatment of teeth #8 and #9 4 months after the initial trauma. Clinical examination showed that tooth #9 had a sinus tract present near the periapical area, was tender to percussion and palpation, and did not respond to pulp sensibility tests. Tooth #8 responded to pulp sensibility tests. Periapical radiographic and cone-beam computed tomographic examination showed that tooth #9 had a periapical radiolucent lesion and severe ERRs with a root perforation. Tooth #9 was diagnosed with a necrotic pulp and symptomatic apical periodontitis. Regenerative endodontic procedures (REPs) were initiated. Tooth #8 became nonresponsive to pulp sensibility tests and developed a periapical lesion 12 months after REPs of tooth #9 and was also treated with REPs. The clinical symptoms and apical lesions resolved for both teeth after REPs. The severe ERRs were arrested, and root perforation was repaired for tooth #9. Teeth #8 and #9 underwent canal obliteration by hard tissue formation after REPs and were in function at 18 months and 30 months, respectively. REPs may be used to manage traumatized immature permanent teeth with a necrotic pulp and apical periodontitis associated with severe ERR and root perforation., (Copyright © 2020 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: External apical root resorption is nearly ubiquitous in people treated orthodontically. This study predicted the extent of external apical root resorption by the vector of the incisor movement., Methods: Cone-beam computed tomography scans of 93 white American adolescents (45 boys, 48 girls) with a Class I malocclusion who received comprehensive orthodontics were analyzed. Half were treated with 4 first-premolar extractions, and the others were treated without extractions. An x, y, z coordinate system was registered on the maxillae, superimposing on foramina, to quantify vectors of maxillary incisor movements. Multiple linear regression identified significant predictors of resorption for each incisor., Results: Strongly predictive models (R 2 = 77%-86%) were obtained. All directions of incisor movement tested (anteroposterior, mediolateral, craniocaudal, torquing) increased the risk of resorption in a dose-response fashion. Intrusion was most damaging. The patient's sex, age, and duration of treatment were not predictive., Conclusions: Root resorption is a very frequent consequence of tooth movement, especially intrusion and torquing, though no direction is harmless, and most corrections occur in combination. Incisor apical resorption was significantly greater in the extraction sample (ca 0.5 mm)., (Copyright © 2020. Published by Elsevier Inc.)

Introduction: Invasive cervical resorption (ICR) is a relatively rare type of ERR (External Root Resorption), in which a localized resorption begins in the cervical area of the tooth, below the epithelial junction and above the ridge crest., Objective: Describe the clinical case of an 11-year-old boy with no dental trauma history, presenting moderate crowding and ectopic eruption of the maxillary right central incisor. He had been undergoing orthodontic treatment elsewhere, and his family was dissatisfied with the results., Description: A new treatment was indicated, which included rapid maxillary expansion followed by extraction of four premolars. During routine panoramic evaluation, a radiolucid image was detected and a periapical radiograph was requested. At this point, an ICR of the maxillary right central incisor was found. The treatment was cautiously finalized and despite the use of light forces, central incisor was severally compromised by ICR and was therefore extracted., Conclusion: This clinical example discusses the importance of routine radiographs for the early diagnoses of ICR.

Introduction: The aim of this study was to establish an intrusive luxation model in rats and observe the pulpal and periodontal outcomes., Methods: The intrusion was experimentally induced by an application of 20-N force on the occlusal surface of maxillary right second molar along the tooth axial using a striking instrument in 3-week-old male Sprague-Dawley rats. Thirty rats were divided into 6 groups (n = 5) and were sacrificed after 3, 7, 14, 30, 60, and 90 days of the surgery. The occurrence of pulpal and periodontal complications was observed by micro-computed tomographic scanning and hematoxylin-eosin staining., Results: All experimental teeth were fully intruded into the alveolar bone with their occlusal surface located at the cervical level of the adjacent first molar. Spontaneous re-eruption initiated at 7 days. At 14 days, 4 teeth (80%, 4/5) partially re-erupted, whereas 2 (40%), 3 (75%), and 4 (100%) teeth completely re-erupted at 30, 60, and 90 days, respectively. Pulp degeneration and inflammation mainly occurred in 4 teeth at 3 days, 5 at 7 days, and 2 at 14 days; after 14 days, pulp calcification was observed in 8 teeth. Ankylosis and replacement root resorption mainly occurred in 1 tooth at 30 days, 2 teeth at 60 days, and 3 at 90 days. Marginal bone loss was observed in 3 teeth (60%) at 30 days, 3 (75%) at 60 days, and 2 (50%) at 90 days., Conclusions: An animal model of intrusive dentoalveolar trauma was successfully established in rats. Pulpal and periodontal complications similar to clinical tooth intrusion were observed, which provided a basis for exploring the mechanisms of complications in the future., (Copyright © 2020 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Background: Orthodontically-induced root resorption is an iatrogenic effect and it cannot be examined regularly due to the harmful effects of sequential doses of radiation with more frequent radiography. This study aims to compare protein abundance (PA) of pre-treatment and during orthodontic treatment for root resorption and to determine potential early markers for root resorption., Methods: Ten subjects (n = 10) who had upper and lower fixed appliances (MBT, 3 M Unitek, 0.022″ × 0.028″) were recruited for this study. Human gingival crevicular fluid (GCF) was obtained using periopaper strips at pre-treatment (T0), 1 month (T1), 3 months (T3), and 6 months (T6) of orthodontic treatment. Periapical radiographs of the upper permanent central incisors were taken at T0 and T6 to measure the amount of root resorption. Identification of changes in PA was performed using liquid chromatography-tandem mass spectrometry. Student's t-test was then performed to determine the significance of the differences in protein abundance before and after orthodontic treatment., Results: Our findings showed that all ten subjects had mild root resorption, with an average resorption length of 0.56 ± 0.30 mm. A total of 186 proteins were found to be commonly present at T0, T1, T3, and T6. There were significant changes in the abundance of 16 proteins (student's t-test, p ≤ 0.05). The increased PA of S100A9, immunoglobulin J chain, heat shock protein 1A, immunoglobulin heavy variable 4-34 and vitronectin at T1 suggested a response to stress that involved inflammation during the early phase of orthodontic treatment. On the other hand, the increased PA of thymidine phosphorylase at T3 suggested growth promotion and, angiogenic and chemotactic activities., Conclusions: The identified proteins can be potential early markers for root resorption based on the increase in their respective PA and predicted roles during the early phase of orthodontic treatment. Non-invasive detection of root resorption using protein markers as early as possible is extremely important as it can aid orthodontists in successful orthodontic treatment.

Objectives: To compare the amount of en-masse retraction with or without piezocision corticotomy, to assess the type of tooth movement, to evaluate root integrity after retraction, and to record reported pain levels., Materials and Methods: This randomized, controlled clinical trial included 26 orthodontic patients requiring premolar extraction. The patients were divided into two groups: (1) an extraction with piezocision corticotomy group (PCG) and (2) an extraction-only group, which served as the control group (CG). Cone-beam computed tomography images were acquired before and 4 months after the initiation of en-masse retraction utilizing miniscrews. The following variables were assessed: the amount of en-masse retraction, incisor inclination, incisor and canine root resorption, and patient-reported pain., Results: Twelve and 11 participants completed the entire study in the PCG and CG, respectively. The amount of en-masse retraction was significantly greater in the PCG compared to the CG (mean = 4.8 ± 0.57 mm vs 2.4 ± 0.33 mm, respectively [P < .001]). There was also significantly less tipping and root resorption of incisors in the PCG (P < .05). The reported pain was significantly higher on the first day in the PCG compared to the CG (P < .001); however, it became similar between the groups after 24 hours., Conclusions: Piezocision corticotomy enhanced the amount of en-masse retraction two times more with less root resorption. However, future studies are required to assess the long-term effects of this technique., (© 2020 by The EH Angle Education and Research Foundation, Inc.)

Purpose: Impacted third molars (M3s) may lead to external root resorption (ERR) and dental caries (DC) in the adjacent second molars (M2s). The aim of this study was to identify the risk factors for ERR and DC in M2s associated with impacted M3s., Materials and Methods: We implemented a cross-sectional study and enrolled a sample composed of patients with M3s and M2s present and cone-beam computed tomography (CBCT) scans available for review. If there was contact between the M2 and the adjacent M3 and the border of radiolucency was more distinct, the case was considered ERR. Apart from that, the case was considered DC. Potential predictor variables were defined as age, gender, tooth location, M2-M3 contact, root development in M3, M3 inclination, M3 impaction type, and M3 follicular diameter. Outcomes of the study were DC and ERR in M2s. CBCT was used to detect the presence of DC and ERR in M2s., Results: A total of 250 eligible images of M3s in the upper and lower jaws of 167 patients were included. The mean age of the patients with CBCT images available was 26.08 ± 4 years (range, 18 to 40), and 43.6% of the patients were men. Factors associated with a significantly increased frequency of ERR in M2s included maxillary location, presence of M2-M3 contact, and mesioangular inclination (P < .005). DC in M2s was significantly more likely to occur in those with absence of contact between M2 and M3 (P < .005)., Conclusions: The results of this study showed an increased risk of ERR to be associated with maxillary molars, mesioangular inclination, and presence of M2-M3 contact. The variable associated with an increased risk of DC was the absence of M2-M3 contact., (Copyright © 2020 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: The present study aimed at comparing the external lateral root resorption (ELRR) and external apical root resorption (EARR) between teeth moved through the atrophic edentulous ridge and those undergoing the usual orthodontic movement., Methods: Fifty-four premolars were evaluated, where 27 of them had been moved toward the edentulous ridge (Group 1) and 27 from the same patient, had not been translated, which comprised the control group (Group 2). ELRR was evaluated by 0-3 scores and EARR was evaluated by 0-4 scores, before and after movement. Measurements were compared by Kruskal-Wallis and Student-Newman-Keuls tests., Results: ELRR increased statistically only in the Group 1 (p< 0.05). After orthodontic treatment, it was observed that almost 56% (n = 15) of teeth in Group 1 presented scores 2 and 3, while Group 2 presented scores 2 and 3 in about 11% (n= 3) of the teeth. EARR increased in both groups after orthodontic movement, however, statistically analyses showed no significant differences between groups (p> 0.05)., Conclusions: Orthodontic movement into the atrophic edentulous ridge is subject to a greater lateral external root resorption.