Cone-beam computed tomography versus periapical radiograph for diagnosing external root resorption: A systematic review and meta-analysis

Quantitative analysis and clinical determinants of orthodontically induced root resorption using automated tooth segmentation from CBCT imaging

BACKGROUND

Orthodontically induced root resorption (OIRR) is difficult to assess accurately using traditional 2D imaging due to distortion and low sensitivity. While CBCT offers more precise 3D evaluation, manual segmentation remains labor-intensive and prone to variability. Recent advances in deep learning enable automatic, accurate tooth segmentation from CBCT images. This study applies deep learning and CBCT technology to quantify OIRR and analyze its risk factors, aiming to improve assessment accuracy, efficiency, and clinical decision-making.

METHOD

This study retrospectively analyzed CBCT scans of 108 orthodontic patients to assess OIRR using deep learning-based tooth segmentation and volumetric analysis. Statistical analysis was performed using linear regression to evaluate the influence of patient-related factors. A significance level of p < 0.05 was considered statistically significant.

RESULTS

Root volume significantly decreased after orthodontic treatment (p < 0.001). Age, gender, open (deep) bite, severe crowding, and other factors significantly influenced root resorption rates in different tooth positions. Multivariable regression analysis showed these factors can predict root resorption, explaining 3% to 15.4% of the variance.

CONCLUSION

This study applied a deep learning model to accurately assess root volume changes using CBCT, revealing significant root volume reduction after orthodontic treatment. It found that underage patients experienced less root resorption, while factors like anterior open bite and deep overbite influenced resorption in specific teeth, though skeletal pattern, overjet, and underbite were not significant predictors.

Automatic 3-dimensional quantification of orthodontically induced root resorption in cone-beam computed tomography images based on deep learning

INTRODUCTION

Orthodontically induced root resorption (OIRR) is a common and undesirable consequence of orthodontic treatment. Traditionally, studies employ manual methods to conduct 3-dimensional quantitative analysis of OIRR via cone-beam computed tomography (CBCT), which is often subjective and time-consuming. With advancements in computer technology, deep learning-based approaches have gained traction in medical image processing. This study presents a deep learning-based model for the fully automatic extraction of root volume information and the localization of root resorption from CBCT images.

METHODS

In this cross-sectional, retrospective study, 4534 teeth from 105 patients were used to train and validate an automatic model for OIRR quantification. The protocol encompassed several steps: preprocessing of CBCT images involving automatic tooth segmentation and conversion into point clouds, followed by segmentation of tooth crowns and roots via the Dynamic Graph Convolutional Neural Network. The root volume was subsequently calculated, and OIRR localization was performed. The intraclass correlation coefficient was employed to validate the consistency between the automatic model and manual measurements.

RESULTS

The proposed method strongly correlated with manual measurements in terms of root volume and OIRR severity assessment. The intraclass correlation coefficient values for average volume measurements at each tooth position exceeded 0.95 (P <0.001), with the accuracy of different OIRR severity classifications surpassing 0.8.

CONCLUSIONS

The proposed methodology provides automatic and reliable tools for OIRR assessment, offering potential improvements in orthodontic treatment planning and monitoring.

Panoramic evaluation of external root resorption in mandibular molars during orthodontic treatment: a comparison between root-filled and vital teeth treated with fixed appliances or clear aligners

BACKGROUND

This investigation compared the extent of external apical root resorption (EARR) in root-filled teeth (RFT) and their contralateral vital pulp teeth (VPT) counterparts during orthodontic treatment (OT) with clear aligner (CA) treatment or fixed appliance (FA) treatment.

METHODS

Sixty-six patients with similar baseline American Board of Orthodontics (ABO) discrepancy index scores were divided into two groups: 37 patients (21 females, 16 males; mean age 17.45 ± 2.67 years) in the FA group, and 29 patients (18 females, 11 males; mean age 18.33 ± 1.96 years) in the CA group. Digital panoramic radiographs captured pre- and post-OT were used to measure tooth lengths and root surface measurements in mandibular molars. EARR in both RFT and contralateral VPT was evaluated pre- and post-OT. Statistical analysis employed paired t-tests, independent t-tests, and analysis of covariance (ANCOVA) (p < .05).

RESULTS

All teeth exhibited varying degrees of EARR following OT. FA treatment resulted in significantly longer treatment duration (p < .05) and greater EARR compared to CA treatment (p < .05). Moreover, statistically significant differences in EARR were observed within both groups between RFT and VPT (p < .05).

CONCLUSIONS

Comparison of pre- and post-OT radiographs revealed different degrees of EARR in all teeth. CA treatment resulted in less frequent and less severe EARR compared to FA treatment. RFT demonstrated greater resistance to EARR than VPT in both treatment groups.

The effect of single versus multiple piezocisions on the rate of canine retraction: a randomized controlled trial

BACKGROUND

Piezocision is a minimally invasive surgical method aiming to accelerate tooth movement. However, its effect was found to be transient, appertaining to the regional acceleratory phenomenon (RAP). Hence, the aim of the study was to evaluate the effect of single and multiple piezocisions on the rate of orthodontic tooth movement (OTM). Moreover, the impact of both protocols on canine tipping and orthodontically induced inflammatory root resorption (OIIRR) has been assessed.

METHODS

Thirty indicated patients for the therapeutic extraction of maxillary first premolars were enlisted in this split-mouth study, and they were randomly split into two equal groups, each including 15 subjects. In the Single Application Group (SAG), one side of the maxillary arch arbitrarily received a single piezocision before the onset of canine retraction, whereas in the Multiple Application Group (MAG), piezocisions were randomly performed on one side, three times on a monthly basis, over the 12-week study period. The contralateral sides of both groups served as the controls. Canine retraction was carried out bilaterally using nickel-titanium closed-coil springs, delivering 150 g of force, and the rate of tooth movement, as well as canine tipping were evaluated on a monthly basis, over a 3-month period. Cone-bean computed tomography scans were also conducted pre- and post- canine retraction, and OIIRR was assessed using Malmgren Index.

RESULTS

The reported outcomes revealed a significant increase in the amount of canine retraction, canine tipping, as well as root resorption scores on the experimental sides in both groups SAG and MAG post-retraction (p < 0.001). However, upon comparing the experimental sides in both groups, non-significant differences have been observed between them regarding all the assessed outcomes (p > 0.05).

CONCLUSIONS

Single and multiple piezocisions effectively accelerate OTM in comparison to conventional orthodontic treatment, with relative outcomes reported by both intervention frequencies. Accordingly, single piezocision is recommended as an adjunct to OTM. Furthermore, significant tooth tipping as well as a significantly higher root resorption risk accompanies both single and multiple piezocision applications in conjunction with OTM.

NAME OF THE REGISTRY

Clinicaltrials.gov TRIAL REGISTRATION NUMBER: NCT05782088 DATE OF REGISTRATION: 23/03/2023 "Retrospectively registered". URL: https://clinicaltrials.gov/ct2/show/NCT05782088.

Diagnostic Accuracy of Cone Beam Computed Tomography and Periapical Radiography for Detecting Apical Root Resorption in Retention Phase of Orthodontic Patients: A Cross-Sectional Study

Objectives: This clinical study aimed to evaluate and compare the diagnostic accuracy of intraoral periapical radiography (PR) and cone beam computed tomography (CBCT) in detecting external apical root resorption (EARR) in orthodontic patients during the retention phase. Methods: The research involved 41 Caucasian patients who had undergone comprehensive orthodontic treatment, with a total of 328 teeth analyzed. The Kappa values for inter- and intra-examiner agreement were high for both PR and CBCT, indicating a robust level of agreement among examiners. The study used a four-point scale for classifying EARR. Results: This study showed comparable accuracy, sensitivity, and specificity between PR and CBCT when using the most stringent criterion of "Definitely present". The data suggested that CBCT outperformed PR when using a less stringent criterion ("Definitely present" or "Probably present"), particularly for maxillary incisors. However, overall diagnostic performance, as measured by the area under the ROC curve, showed only a slight advantage for CBCT over PR. Areas under the ROC curve range between 0.85 and 0.90 for PR and between 0.89 and 0.92 for CBCT. According to DeLong's test, there is no evidence to conclude that the area under the ROC curve is different for PR and CBCT. Conclusions: Both PR and CBCT are accurate diagnostic tools for identifying EARR, with PR being deemed more suitable for routine clinical use due to its cost-effectiveness and lower radiation exposure. The findings emphasize the importance of considering the risk-benefit ratio when deciding on imaging modalities for monitoring EARR in orthodontic patients.

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.

Diagnostic accuracy of conventional orthodontic radiographic modalities and cone-beam computed tomography for localization of impacted maxillary canine teeth

BACKGROUND

Orthodontic treatment planning for an impacted canine tooth requires accurate information about its position. The aim of this study was to compare the diagnostic accuracy of two conventional orthodontic radiographic modalities with cone-beam computed tomography (CBCT) for localization of impacted maxillary canine teeth.

MATERIALS AND METHODS

Panoramic radiographs, lateral cephalograms, and CBCT scans of 30 patients with unilaterally impacted maxillary canine teeth were retrieved from the archives. Eight expert orthodontists evaluated the parameters related to the location of impacted canine teeth by using panoramic radiographs and lateral cephalograms of patients. After 4 weeks, the same parameters were evaluated on CBCT scans of patients. The diagnostic accuracy of conventional modalities and CBCT was compared with each other and also with the gold standard.

RESULTS

The conventional radiographic modalities and CBCT had similar accuracy for assessment of the overall inclination (p = 0.11), apex morphology (p = 0.18), and mesiodistal position of the apex (p = 0.12). CBCT had significantly higher accuracy for determination of incisal tip location (p = 0.001), labiopalatal (p = 0.001) and vertical (p = 0.01) position of the crown tip, minimum bone thickness covering the crown (p = 0.001), and root resorption of the adjacent tooth (p = 0.001).

CONCLUSION

The combination of panoramic radiographs and lateral cephalograms was sufficiently accurate to assess some diagnostic parameters such as overall inclination, apex morphology, and mesiodistal apex location of impacted canine teeth.

The effect of impacted third molars on second molar external root resorption, a cross-sectional cone beam computed tomography study

BACKGROUND

Third molars have the highest prevalence of impaction in teeth and can cause pathological damage on the adjacent second molars. This study aims to evaluate the effects of factors related to impacted third molars on external root resorption (ERR) in adjacent second molars using cone-beam computed tomography (CBCT).

MATERIAL AND METHODS

In CBCTs, the effect of impacted third molars on the root surface of adjacent second molars was investigated. Inclusion criteria for subjects were being older than 16 and younger than 55, presence of at least one impacted third molar and adjacent second molar. Exclusion criteria were pathology, a follicle gap greater than 5 mm, crowned second molar, severe decay, an artifact on a radiologic image, and previous surgery on the second or third molars. The investigations were made based on age range, gender, tooth inclination, Pell-Gregory classification, retention type, contact area, root formation, pericoronal width, and tooth absence on the same quadrant for potential risk factors. The collected data were statistically analyzed with R software. The Chi-Square test was used to find out any significant difference. Logistic regression analyses were done for potential risk factors for ERR.

RESULTS

A total of 437 impacted third molars and adjacent second molars were investigated using CBCT. Of these, 381 met the inclusion criteria. Mesioangular and horizontal inclination, Pell-Gregory Class B-C, contact area, and retention type were found the statistically potential risk factors for ERR.

CONCLUSIONS

The impacted third molar with horizontal or mesioangular position, and osseous retention, with Pell and Gregory Class B and C, are more likely to cause external root resorption in adjacent second molars.

Could the pulp be preserved in tooth with root resorption caused by embedded tooth?

Background/purpose

At present, there are no recognized guidelines or consensus for the treatment strategy of the asymptomatic tooth with external root resorption caused by an embedded tooth (et-ERR). Most clinicians would like prophylactic or concomitant root canal therapy (RCT) along with the extraction of the embedded tooth. The purpose of this study was to report the prognosis of external root resorption (ERR) and investigate the possibility to preserve the vital pulp of ERR tooth.

Materials and methods

The patients who had asymptomatic et-ERR teeth were included. After extraction of the embedded tooth, the clinical process, prognosis, and adverse events were observed, including symptoms, clinical, and radiographic examination throughout the follow-up period.

Results

A total of four cases with special features were reported. Over a follow-up period of up to 12 months, on clinical examination, 3 ERR teeth preserved pulp vitality without additional intervention except for tooth extraction and have kept normal function free from any symptoms. Radiographic examination showed bone regeneration and recovery of periodontal tissue. While one case failed to keep the vital pulp and ended in intentional replantation.

Conclusion

As to et-ERR, if the embedded tooth can be promptly extracted with a minimally invasive technique and effective infection control, the pulp vitality of the et-ERR tooth is likely to be preserved. In this situation, the preferred management of asymptomatic et-ERR tooth is just followed up without prophylactic RCT.

Under pressure-mechanisms and risk factors for orthodontically induced inflammatory root resorption: a systematic review

BACKGROUND

The application of orthodontic forces causes root resorption of variable severity with potentially severe clinical ramifications.

OBJECTIVE

To systematically review reports on the pathophysiological mechanisms of orthodontically induced inflammatory root resorption (OIIRR) and the associated risk factors based on in vitro, experimental, and in vivo studies.

SEARCH METHODS

We undertook an electronic search of four databases and a separate hand-search.

SELECTION CRITERIA

Studies reporting on the effect of orthodontic forces with/without the addition of potential risk factors on OIIRR, including (1) gene expression in in-vitro studies, the incidence root resorption in (2) animal studies, and (3) human studies.

DATA COLLECTION AND ANALYSIS

Potential hits underwent a two-step selection, data extraction, quality assessment, and systematic appraisal performed by duplicate examiners.

RESULTS

One hundred and eighteen articles met the eligibility criteria. Studies varied considerably in methodology, reporting of results, and variable risk of bias judgements.In summary, the variable evidence identified supports the notion that the application of orthodontic forces leads to (1) characteristic alterations of molecular expression profiles in vitro, (2) an increased rate of OIIRR in animal models, as well as (3) in human studies. Importantly, the additional presence of risk factors such as malocclusion, previous trauma, and medications like corticosteroids increased the severity of OIIRR, whilst other factors decreased its severity, including oral contraceptives, baicalin, and high caffeine.

CONCLUSIONS

Based on the systematically reviewed evidence, OIIRR seems to be an inevitable consequence of the application of orthodontic forces-with different risk factors modifying its severity. Our review has identified several molecular mechanisms that can help explain this link between orthodontic forces and OIIRR. Nevertheless, it must be noted that the available eligible literature was in part significantly confounded by bias and was characterized by substantial methodological heterogeneity, suggesting that the results of this systematic review should be interpreted with caution.

REGISTRATION

PROSPERO (CRD42021243431).

Assessment of Digital Intraoral Periapical Radiograph for the Detection of Apical Root Resorption in Inflammatory Periapical Pathologies: A Radiovisiography Study

Introduction Resorption often takes the form of external inflammatory root resorption. Apical periodontitis or an apical cyst is the most typical cause of external inflammatory root resorption. Failure of endodontic treatment can occur if severe apical root resorption occurs.This is due to the difficulty of reaching these sites.Apical root resorption is usually discovered during routine radiographs and is usually in its later stages. If the lesion is advanced, extraction is the only viable solution. An accurate diagnosis of incipient root resorption is essential. This research is designed to analyze the effectiveness of digital intraoral periapical radiographs in assessing apical root resorption (ARR) related to periapical pathologies. Material and methods This cross-sectional radiographic observational research was conducted in a dental college and hospital in central India. Radiovisiography (RVG) images of 190 patients' teeth with inflammatory periapical pathologies were evaluated to determine the presence or absence of resorption in the apical area of the root. After the radiographic assessment of the apical root resorption, the extraction of the affected teeth was done under all aseptic conditions. The periapical tissue was sent for histological analysis and the extracted tooth sample was examined for the presence or absence of apical root resorption. Results In comparison to apical periodontitis, the proportion of severe root resorption patients was significantly higher in abscess and periapical granuloma. Using Pearson's Chi-square test, the difference in patient proportions according to the kind of resorption in the three radiological diagnosis groups was statistically significant with a p-value of 0.0058. Conclusion It was concluded that on radiographic examination, digital intraoral periapical radiographs were found to be accurate in determining periapical apical pathologies and apical root resorption.

External Inflammatory Root Resorption in Traumatized Immature Incisors: MTA Plug or Revitalization? A Case Series

INTRODUCTION

External inflammatory root resorption (EIRR) in immature permanent teeth is a common complication after severe dental trauma. The management of this condition requires thorough disinfection of the root canal in order to arrest the resorptive process. However, current guidelines regarding the recommended treatment of EIRR following traumatic dental injuries vary, mainly in regard to the type of intracanal medication and its retention time in the root canal system. The objective of this case series was to present both the apical barrier technique (MTA plug) and revitalization procedures as valid treatment options in immature teeth with EIRR.

METHODS

Four cases of post-traumatic immature teeth diagnosed with pulp necrosis and EIRR, with or without apical periodontitis, were treated either by an MTA plug (two teeth) or revitalization (two teeth). Cases were followed between 12 and 24 months.

RESULTS

Both treatment methods were efficient in arresting EIRR and enabled bone healing. After revitalization, partial root maturation was observed.

CONCLUSION

Whereas the key to achieve periodontal healing in cases of EIRR is thorough disinfection of the root canal, both a subsequent MTA plug as well as revitalization may represent adequate treatment methods. An additional benefit lies in the potential of revitalization to promote further root maturation through hard tissue apposition.

DIAGNOSTIC PERFORMANCE OF CONE-BEAM COMPUTED TOMOGRAPHY TO DIAGNOSE IN VIVO/IN VITRO ROOT RESORPTION: A SYSTEMATIC REVIEW AND META-ANALYSIS

BACKGROUND

This review analyses the diagnostic performance of cone-beam computed tomography (CBCT) for the in vivo/in vitro detection of external root resorption (ERR) and critically analyses current and past methods of measuring or classifying ERR in vivo/in vitro in terms of radiation doses and cumulative radiation risks.

METHODS

A diagnostic test accuracy (DTA) protocol was used for a systematic review of diagnostic methods following PRISMA guidelines. The protocol was registered with PROSPERO (ID: CRD42019120513). A thorough and exhaustive electronic search of 6 core electronic databases was performed, applying the ISSG Search Filter Resource. The eligibility criteria were designed [problem-intervention-comparison-outcomes (PICO) statement: Population, Index test, Comparator, Outcome] and methodological quality was assessed by QUADAS-2.

RESULTS

Seventeen papers were selected from a total of 7841 articles. Six in vivo studies were assessed as having a low risk of bias. The overall sensitivity and specificity of CBCT for diagnosis of ERR was 78.12% and 79.25%, respectively. The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%.

DISCUSSION

Most of the selected studies reported quantitative diagnoses with single linear measurements of ERR even though multislice radiographs were available. The cumulative radiation dose (μS) to radiation-sensitive structures, such as the bone marrow, brain and thyroid, was observed to increase using the 3-dimensional (3D) radiography methods reported.

CONCLUSIONS

The highest and lowest sensitivity and specificity of CBCT for diagnosis of external root resorption are 42%-98% and 49.3%-96.3%. The minimum and maximum effective doses of dental CBCT for external root resorption diagnosis are 34 μSv and 1073 μSv.

Impact of micro-osteoperforations on root resorption and alveolar bone in en-masse retraction in young adults: A CBCT randomized controlled clinical trial

BACKGROUND

Micro-osteoperforations (MOPs) as a surgical technique is increasingly being used as a method to enhance orthodontic tooth movement. However, its iatrogenic effects on root and alveolar bone morphology have been less studied.

OBJECTIVE

This parallel-groups single-centered trial aimed to assess the impact of micro-osteoperforations (MOPs) on orthodontically induced inflammatory root resorption (OIIRR) and alveolar bone during en-masse retraction stage of maxillary and mandibular anterior teeth.

METHODS

Fifty-two patients (mean age 21.35±2.2 years) with Class I bi-dentoalveolar protrusion, requiring all 1st premolar extractions and miniscrews for anchorage, were randomly distributed into two groups (n=26 each): MOP group treated using single application of MOP's and control group treated with routine sliding mechanics, for en-masse retraction. The primary outcomes were assessed using CBCT-based measurements.

RESULTS

Anterior teeth in MOP group showed increased mean OIIRR than control group, though the difference was statistically non-significant [maxillary anteriors, MOP group - OIIRR=0.78±0.29mm and control group OIIRR=0.73±0.36mm; mandibular anteriors, MOP group - OIIRR=0.733±0.20mm and control group OIIRR=0.70±0.24mm]. Levander and Malmgren's Index for objective scoring of OIIRR revealed only mild resorption with most teeth in both the groups (47% and 51%, respectively). Lateral incisors showed highest OIIRR followed by central incisors and canines in both groups. Lingual side bone thickness and height decreased significantly, however, the differences between the two groups were non-significant (P>0.05).

CONCLUSION

Within the settings of the current RCT, en-masse retraction when combined with single application of micro-osteoperforations did not pose an increased risk of root resorption or alveolar bone changes compared to routine sliding mechanics.

Calcifying odontogenic cyst resembling clinical signs of vertical root fracture of a maxillary canine

BACKGROUND

Calcifying odontogenic cyst (COC) can be misdiagnosed as a lesion of endodontic origin when it is in close proximity to the periradicular tissue, and pulp sensibility tests are indispensable for differential diagnosis. However, when the adjacent teeth are necrotic or already endodontically treated, diagnosis becomes challenging.

CASE DESCRIPTION

In this case report, a maxillary canine with an inadequate root canal treatment was considered as the source of an endodontic infection. Eight months after the retreatment, the patient sought treatment for a buccal intraoral swelling and a deep periodontal pocket and was referred for cone-beam computed tomography with a provisional diagnosis of a vertical root fracture. The tomography revealed an extensive lesion buccally to the roots of the canine and the adjacent vital lateral incisor. An unusual extended external resorption of the root of the vital lateral incisor was also evident. This finding shifted the diagnostic thinking toward a lesion of nonendodontic origin. The lesion was surgically enucleated, and the histopathologic examination confirmed the diagnosis of a COC.

PRACTICAL IMPLICATIONS

Clinicians always must bear in mind the chance of a nonendodontic lesion masquerading as a lesion of endodontic origin. Cone-beam computed tomography should be considered in cases of doubt or in lesions refractory to endodontic treatment, as it can provide information on the clinicopathologic features of the lesion.

External apical root resorption in orthodontic tooth movement: the risk factors and clinical suggestions from experts' consensus

External apical root resorption is among the most common risks of orthodontic treatment, and it cannot be completely avoided and predicted. Risk factors causing orthodontic root resorption can generally be divided into patient- and treatment-related factors. Root resorption that occurs during orthodontic treatment is usually detected by radiographical examination. Mild or moderate root absorption usually does no obvious harm, but close attention is required. When severe root resorption occurs, it is generally recommended to suspend the treatment for 3 months for the cementum to be restored. To unify the risk factors of orthodontic root resorption and its clinical suggestions, we summarized the theoretical knowledge and clinical experience of more than 20 authoritative experts in orthodontics and related fields in China. After discussion and summarization, this consensus was made to provide reference for orthodontic clinical practice.

Evaluation of root resorption in maxillary anterior teeth during orthodontic treatment with a fixed appliance based on panoramic radiographs

PURPOSE

The aim of this study was to evaluate the frequency of apical root resorption in the anterior teeth of the maxilla visible on panoramic images during orthodontic treatment with a fixed appliance.

MATERIAL AND METHODS

A total of 194 panoramic radiographs of patients with a fixed appliance in the upper arch were analysed to evaluate the severity of root resorption in maxillary incisors and canines according to Levander and Malmgren classification. The research group included 135 females and 59 males, aged 15-28 years, with a mean 20.6 years.

RESULTS

Of examined patients 75.26% had signs of apical root resorption. The tooth most frequently affected by resorptive changes was the right central upper incisor. The gender and age of the patients were not found to be significant factors. The highest number of teeth had second (II) stage root resorption (53.09%).

CONCLUSIONS

Panoramic radiographs can be useful in diagnosing external apical root resorption due to orthodontic treatment.

The influence of two photobiomodulation protocols on orthodontically induced inflammatory root resorption (a randomized controlled clinical trial)

Background

Controversial results have been reported regarding the impact of photobiomodulation (PBM) on orthodontically induced inflammatory root resorption (OIIRR). The aim of this study was to evaluate the influence of two PBM protocols, one of them requiring a high application frequency (on days 0, 3, 7, 14, then every 2 weeks), while the second requires less frequent applications (every 3 weeks), on OIIRR accompanying orthodontic treatment.

Methods

Twenty female patients were recruited for this randomized controlled trial, requiring the therapeutic extraction of maxillary first premolars, and they were randomly divided into 2 equal groups. In Group A, one side of the maxillary arch randomly received PBM on days 0, 3, 7, 14, and every 2 weeks thereafter, while in Group B, one side was randomly chosen to receive PBM every 3 weeks. The laser applied was a Diode laser with a wavelength of 980 nm, in a continuous mode. Canine retraction in both groups was carried out using closed-coil springs, delivering 150 g of force, and the force level was checked every 3 weeks, over a 12-week study period. Pre-retraction and post-retraction cone-beam computed tomography (CBCT) was done for the evaluation of OIIRR.

Results

No significant differences in the amount of OIIRR have been reported between the laser and control sides in both groups A and B. Also, no significant differences have been reported between the laser sides in both groups.

Conclusions

Photobiomodulation does not affect OIIRR, whether by increasing or decreasing its occurrence, with both laser application protocols. Therefore, it can be stated that PBM does not result in root resorption less than the commonly observed range elicited with conventional orthodontic treatment, and that it has no effect on OIIRR.

Trial registration Two Low-level Laser Irradiation Protocols on the Rate of Canine Retraction (NCT04926389), 15/06/2021—retrospectively registered. https://clinicaltrials.gov/ct2/show/NCT04926389.

Comparison of CBCT and panoramic radiography for the assessment of bone loss and root resorption on the second molar associated with third molar impaction: a systematic review

OBJECTIVE

To investigate whether the use of cone beam CT (CBCT) changes the diagnosis of external root resorption (ERR) or marginal bone loss (MBL) involving a second molar adjacent to an impacted third molar.

METHODS

A systematic search was applied in PubMed, EMBASE, Scopus, Web of Science, LILACS, Google Scholar, OpenGrey, and ProQuest. Studies assessing the detection of ERR or MBL in a second molar adjacent to an impacted third molar through CBCT and panoramic radiography (PAN) were included. Prevalence and agreement between PAN and CBCT on the detection of ERR and MBL were collected. The risk of bias was assessed using the MAStARI.

RESULTS

A total of 593 papers were identified, and after a 2-phase selection, 5 studies were included in the narrative synthesis. Regarding ERR, its prevalence in PAN was reported from 5.31 to 19.5% and from 22.8 to 62.0% in CBCT. The percentage of agreement varied from 28.5 to 74.0%. The prevalence of MBL varied from 21.9 to 62.9% in PAN, while those values varied from 21.6 to 80% in CBCT images. The percentage of agreement between PAN and CBCT for the detection of MBL ranged from 66.0 to 85.0%. Four studies presented low risk of bias and one had moderate risk.

CONCLUSIONS

More ERR and MBL are assessed in CBCT compared to PAN. There is a considerable agreement between PAN and CBCT assessment of ERR and MBL, however, mostly related to the absence of the pathology rather its presence.

Management of Class III Extraction with the Miniscrew-Supported Orthodontic Pseudo-Ankylosis (MSOPA) Using Direct Tads

The aim of the present study is to represent the orthodontic treatment of a young patient with a skeletal Class III malocclusion(Wits Appraisal −9 mm), in which the extractions of the first lower premolars were performed to obtain a class III camouflage using direct temporary anchorage devices (TADs). The patient reported a history of three years of orthodontic treatment at another clinic and the radiographic evaluation revealed an important impairment of the upper root incisors. A treatment was performed with a fixed appliance in the upper and lower arches using an archwire sequence of 0.16 CuNiTi, 19 × 25 CuNiTi, 19 × 25 SS and was carried out in 18 months. Post-treatment records of our patient show a control of facial esthetics from the frontal and lateral perspectives, with a harmonious soft-tissue profile. A Class I canine was achieved and her overbite and overjet were normalized by retracting the mandibular anterior teeth and carrying out a bodily mesialization of the posterior sector into the extraction space. In conclusion, the “pseudoankylosis system” used in this case allowed the desired result to be achieved with minimal change to the lower incisal inclination and without overloading the anterior upper and lower sectors, thus reducing the risk of further root resorption and patient compliance.

The influence of bracket torque on external apical root resorption in bimaxillary protrusion patients: a retrospective study

Background

To evaluate the difference in root resorption between standard torque self-ligating brackets and high torque self-ligating brackets in bimaxillary protrusion patients after orthodontic treatment.

Methods

Pre-treatment and post-treatment Cone beam computed tomography (CBCT) of 32 patients (16 treated with the high torque DamonQ 0.022″ bracket and 16 with the 0.022″ standard torque self-ligating bracket) were selected. The first premolars were extracted from all patients before treatment. After mini-screw implants were inserted into the buccal region between the second premolar and first molar, 150 g of force was applied to retract the upper and lower anterior teeth to close the extraction space on each side. CBCT images of all patients were taken before and after treatment. Three-dimensional reconstruction of the maxillary central incisor, lateral incisor and canine was conducted with Mimics 20.0 software. The volumes of the roots were calculated using Gomagics Studio 12.0 software. The differences between the pre-treatment and post-treatment root volumes were statistically evaluated with a paired-samples t-test.

Results

There was no statistically significant difference in root resorption degree between the two kinds of torque brackets. The patient’s degree of root resorption in the high torque self-ligating group was greater than that in the standard torque group.

Conclusions

There was no significant difference in root external apical resorption between the high torque self-ligating brackets and the standard torque self-ligating brackets in bimaxillary protrusion patients.

Comparison of imaging modalities in the diagnosis of external cervical resorption (ECR): an in-vitro study

External cervical resorption is a pathological condition affecting the cervical margins of teeth. Due to the increased prevalence and the area it affects, it can be easily misdiagnosed. The ability of clinicians to diagnose ECR and subcategorise the lesions using periapical radiographs and cone beam-CT scans has not been investigated in-depth. This study aims to assess if diagnostic ability to detect ECR lesions with the two modalities was different and if there was a change in the diagnosis when CBCT was used. A human skull, including the mandible was used for this study. The teeth were randomly allocated to the different subcategories, then pre and post-preparation radiographs with CBCT were taken. Statistical analysis was done using IBM SPSS version 16.0 (SPSS Inc., Chicago, IL, USA). The study sample was composed of 60 participants, the overall sensitivity of intraoral radiographs was significantly lower than CBCT. When the participants were told the radiograph and the CBCT were of the same tooth 60% said they would change their diagnosis. The use of intraoral radiographs alone might not be enough to identify and correctly diagnose ECR lesions. CBCT can give a better idea about the nature and the extent of the lesion.

Biocompatible orthodontic cement with antibacterial capability and protein repellency

BACKGROUND

White spot lesions (WSLs) often occur in orthodontic treatments. The objectives of this study were to develop a novel orthodontic cement using particles of nano silver (NAg), N-acetylcysteine (NAC) and 2-methacryloyloxyethyl phosphorylcholine (MPC), and to investigate the effects on bonding strength, biofilms and biocompatibility.

METHODS

A commercial resin-modified glass ionomer cement (RMGIC) was modified by adding NAg, NAC and MPC. The unmodified RMGIC served as the control. Enamel bond strength and cytotoxicity of the cements were investigated. The protein repellent behavior of cements was also evaluated. The metabolic assay, lactic acid production assay and colony-forming unit assay of biofilms were used to determine the antibacterial capability of cements.

RESULTS

The new bioactive cement with NAg, NAC and MPC had clinically acceptable bond strength and biocompatibility. Compared to commercial control, the new cement suppressed metabolic activity and lactic acid production of biofilms by 59.03% and 70.02% respectively (p < 0.05), reduced biofilm CFU by 2 logs (p < 0.05) and reduced protein adsorption by 76.87% (p < 0.05).

CONCLUSIONS

The new cement with NAg, NAC and MPC had strong antibacterial capability, protein-repellent ability and acceptable biocompatibility. The new cement is promising to protect enamel from demineralization during orthodontic treatments.

The clinical management of orthodontically-induced external root resorption: A questionnaire survey

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.

Comparison between periapical radiography and cone beam computed tomography for the diagnosis of anterior maxillary trauma in children and adolescents

BACKGROUND/AIMS

Under-estimating the damage caused by trauma to the dental structures may delay treatment. Timely and accurate diagnosis remains challenging in clinical practice. Radiography is an important modality for the diagnosis of traumatic injuries. The aim of this study was to compare the efficacy of periapical radiography and cone beam computed tomography for the diagnosis of trauma to the anterior maxillary dentoalveolar region in children and adolescents.

MATERIAL AND METHODS

Images of patients who underwent both periapical radiography and cone beam computed tomography simultaneously because of trauma to the anterior maxillary region between January 2016 and January 2020 were analyzed retrospectively. Pairwise comparison between the receiver operating characteristic curves was performed to statistically compare the two methods for the diagnosis of crown fractures, root fractures, alveolar bone fractures and luxations, tooth resorption, and periapical radiolucencies.

RESULTS

A total of 190 patients met the inclusion criteria. There were 120 (63.2%) males and 70 (36.8%) females, with a mean age of 11.1 years (range: 6-17 years). A crown fracture was observed in 144 teeth, while a root fracture was observed in 71 teeth. Alveolar fracture and luxation were observed in 44 incisors. During follow-up, tooth resorption and periapical radiolucencies were observed in 25 and 33 teeth, respectively. Pairwise receiver operating characteristic curve analysis revealed that cone beam computed tomography was significantly superior to periapical radiography for the diagnosis of root fractures, alveolar fractures and luxations, and tooth resorption (p < .05). However, no significant differences were found for the diagnosis of crown fractures and periapical radiolucencies (p > .05).

CONCLUSIONS

Cone beam computed tomography in the low-dose mode was better for diagnosing root and bone fractures and resorption, but no different to periapical radiographs for crown fractures and periapical radiolucencies in pediatric patients.

Evaluation of apical root resorption in Class III patients who received one- or two-phase orthodontic treatment

Objectives:

The aim of this study was to compare the incidence root resorption and dilaceration between the patients with and without previous orthopedic treatment after the fixed orthodontic treatment.

Materials and Methods:

The pre- and post-treatment digitized panoramic films of 40 Class III adult patients meeting the inclusion criteria were selected from patient population of the orthodontic department. Half of the patients were treated with two-phase treatment (orthopedic therapy followed by fixed appliance treatment; Group 1), while the others wore only fixed appliances (Group 2). Root resorption was evaluated from the first molar to the first molar for each arch using the ImageJ software (Bethesda, Maryland, USA). The presence of root dilacerations was also recorded on the pre-treatment panoramic radiographs. Paired samples t-test and Mann– Whitney U-test were used to compare root length.

Results:

Intragroup comparisons for each tooth indicated that the upper and lower incisors, first molars and upper left second premolars presented a significant decrease in Group 1 (P < 0.05). In contrast, in Group 2, a significant decrease in tooth length was found only in the upper incisors (P < 0.05). Intergroup comparisons for root length change indicated statistically significant differences for the lower incisors, upper second premolars, and all first molars except for the upper left molars (P < 0.05). Nevertheless, the prevalence of root dilaceration in Group 1 was higher than that in Group 2.

Conclusion:

Class III patients who received two-phase treatments experienced more root resorption and dilaceration compared with patients who received one-phase treatments. It should be remembered that early orthopedic forces may have potential adverse effects on a dental root in the long-term.

CBCT influences endodontic therapeutic decision-making in immature traumatized teeth with suspected pulp necrosis: a before-after study

OBJECTIVE

To evaluate the impact of cone-beam computed tomography (CBCT) in endodontic therapeutic decision-making of immature traumatized teeth with suspected pulp necrosis.

METHODS

Over two years, consecutive patients with a dental trauma in their front teeth (apex >0.5 mm) and with suspected pulp necrosis based on clinical and radiographic findings were referred to a specialist clinic in Sweden. Fifteen patients aged 6-13 (18 teeth) were included and clinically examined by an endodontist. Intraoral radiographs and CBCT examinations were obtained. Five practitioners, three endodontists and two residents in endodontics, used these examinations to determine the most appropriate treatment for the 18 cases (all central incisors) on two occasions scheduled 19 weeks apart. On the first occasion, the practitioners had access to clinical information and the intraoral radiographs ('before' CBCT); on the second occasion, the practitioners had also access to a radiologist report and the CBCT images ('after' CBCT). Their treatment plans - no treatment, watchful waiting, endodontic orthograde treatment, or extraction - were made anonymously and independently. Results were analysed using descriptive statistics and Wilcoxon signed-rank test.

RESULTS

'After' CBCT, practitioners changed treatment plans in 30% of the 90 assessments, 74% of which were more aggressive (p = 0.028). In 49% of the assessments, practitioners who chose the watchful and waiting treatment plan 'before' CBCT changed to a more aggressive therapy such as endodontic orthograde treatment and extraction 'after' CBCT (p = 0.005).

CONCLUSION

This study provides evidence that CBCT influences endodontic therapeutic decision-making regarding immature traumatised teeth with suspected pulp necrosis, chiefly when expectant management (i.e., watchful and waiting) was selected before access to CBCT.

[Effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption]

In recent years, developing new methods to accelerate orthodontic tooth movement (OTM) has attracted extensive attention in the field of orthodontic clinical and scientific research. It reduces orthodontic treatment time and risks. Over the past, various approaches have been done to accelerate orthodontic tooth movement. Several forms of corticotomy techniques have been effective in inducing rapid tooth movement. These techniques activate regional acceleratory phenomenon and create a favorable microenvironment for accelerating tooth movement. Root resorption is one of most common side effects of orthodontic treatment. It affects the long-term viability and health of teeth. However, the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption still remains unclear. Accelerating tooth movement may have two-side effects on root resorption. Through shortening the treatment period and removing the hyalinized tissues, the acceleration of orthodontic tooth movement could reduce root resorption. The increase of root resorption might be due to the local inflammation and function of cementoclasts/odontoclasts. In this paper, we reviewed the effects of different corticotomy techniques accelerating orthodontic tooth movement on root resorption. Corticotomy techniques deal with mucoperio-steal flaps and bone tissues differently and develop towards minimally invasive. Previous studies on root resorption use two-dimensional images, including apical films and panoramic tomography, to evaluate the degree of root resorption. In recent years, researches measure the volume of root resorption accurately using cone-beam computed tomography (CBCT) and micro-CT. Most studies suggest that the root resorption during acceleration of orthodontic tooth movement through corticotomy techniques is not statistically different from that of traditional orthodontic treatment. Some studies using micro-CT have shown that the root resorption in the groups of corticotomy techniques increases compared with the control group without surgery. Because of the short duration of these studies, the clinical significance is controversial on the overall impact of corticotomy techniques on orthodontic treatment. Accelerating orthodontic tooth movement is still at its emerging phase and need further research in the form of clinical trials to illustrate the effect of corticotomy techniques accelerating orthodontic tooth movement on root resorption.

Root Resorption of Maxillary Posterior Teeth after Rapid Maxillary Expansion: A Comprehensive Review of the Current Evidence from in-vitro and in-vivo Studies

Background:

The application of heavy forces to the dentition, as those produced during a Rapid Maxillary Expansion (RME), has been associated in the literature with the development of root resorption of maxillary posterior teeth.

Objective:

The aim of the present manuscript was to report the available data from in-vitro and in-vivo studies that can elucidate the biological processes of resorption and repair of radicular cementum after RME.

Methods:

Studies evaluating the occurrence of root resorption after RME by means of histological and radiographic methodology were included. We detailed the changes of the radicular anatomy after RME and provided a synthesis of the most valuable scientific evidence showing the biological processes behind the potential modifications of radicular anatomy. Results. Loss of cementum material and reduction of radicular volumes were seen after rapid maxillary expansion. A small radicular volumetric recovery of anchored teeth occurred after the retention period; this reparative phenomenon was caused by cementum deposition without the reattachment of periodontal fibers, supporting the detrimental effects associated with RR.

Conclusion:

Retention period and the timing of radiographic examination could influence the extension of radicular resorption detected after RME since root resorption and cementum repair may occur at the same time at this stage.

Two decades of research on CBCT imaging in DMFR - an appraisal of scientific evidence

OBJECTIVE

This article aims to appraise how scientific evidence related to CBCT has changed over the years, based on levels of evidence and diagnostic efficacy.

METHODS

A general search strategy was used in different databases (Pubmed, Embase, and Web of Science) to identify systematic reviews (SRs) on CBCT until November of 2020. The SRs included were divided according to different specialties of dentistry. A critical review of the articles was made, describing the level of evidence and efficacy.

RESULTS

In total, 75 articles were selected. There was an increase in the number of SRs on CBCT from 2014 onwards, as 83% of the SRs on this topic were published after 2013, and 72% between 2016 and to date. Twenty SRs (27%) performed meta-analysis. Only 28% of the SRs provided a detailed description of CBCT protocols. According to SR evidence, almost all specialties of dentistry have advanced concomitantly with the introduction of CBCT. The majority of SRs were related to clinical applications (level 2 of efficacy), followed by technical parameters (level 1 of efficacy). Only some CBCT models were mentioned in the SRs selected.

CONCLUSION

Over the course of 20 years, SRs related to CBCT applications for a broad range of dental specialties have been published, with the vast majority of studies at levels 1 and 2 of diagnostic efficacy. Not all CBCT models available on the market have been scientifically validated. At all times, one should remain cautious as such not to simply extrapolate in vitro results to the clinical setting. Also, considering the wide variety of CBCT devices and protocols, reported results should not be overstated or generalized, as outcomes often refer to specific CBCT devices and protocols.

Evidence mapping and quality assessment of systematic reviews in dental traumatology

BACKGROUND/AIMS

Evidence mapping of systematic reviews (SRs) systematically and comprehensively identifies, organizes, and summarizes the distribution of scientific evidence in a field. The aims of this study were to delineate domains in dental traumatology (DT), evaluate the existing SRs within the domains, and identify the paucity of evidence for future research.

METHODS

Domains and sub-domains of DT were established according to the methods of qualitative research. The protocol for evidence mapping was prepared as per the guidelines of GEM and PRISMA. The search strategy was formulated using words and MeSH terms in eight databases without restriction of languages and year of publication. Gray literature, protocol registries, and references of selected articles were also searched. Duplicates were removed, and the final selection of SRs was completed. Data extraction and quality analysis using the ROBIS tool and the PRISMA checklist were performed.

RESULTS

The overall search resulted in 64 SRs from 1999 to 2020 with 44 published in last six years. The highest number of SRs had been performed in the Prognostic domain (n = 19) followed by the domains of Epidemiology (n = 15), Therapeutics (n = 10), Oral Biology (n = 7), Diagnostics (n = 6), Preventive (n = 5), and Research Methods (n = 2). Within each domain, there were variabilities in the number of reviewers, a priori protocols, search limitations, risk of bias methods, and meta-analysis. Of the SRs, including 4 Cochrane reviews, 28.4% were inconclusive. A low risk of bias was found in 48.4% of the SRs. Among the registered and ongoing SRs, six were from the domain of epidemiology, two in the domain of therapeutics, five from prognostics, and one each in the domains of prevention and research methods.

CONCLUSION

The SRs in DT could be mapped in seven domains with variabilities in the methods. The majority had an a priori registered protocol and a low risk of reporting errors. Within the Epidemiology and Preventive domains, SRs were present in all the sub-domains with the majority demonstrating low-risk of bias (ROB). The domain of prognosis had SRs in most sub-domains but with a high ROB. Insufficient numbers of SRs were present in most sub-domains of the Diagnostics, Therapeutics, Research Methods and Oral Biology domains.

External apical root resorption and vectors of orthodontic tooth movement

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 (R² = 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).

Evaluation of Risk Factors for External Root Resorption and Dental Caries of Second Molars Associated With Impacted Third Molars

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.

Prevalence and severity of apical root resorption during orthodontic treatment with clear aligners and fixed appliances: a cone beam computed tomography study

Background

Fixed appliances have been the mainstream for orthodontic treatment, while clear aligners, such as Invisalign system, have become increasingly popular. The prevalence of apical root resorption (ARR) in patients with clear aligners is still controversial. The aim of this study was to investigate and compare the prevalence and severity of ARR in patients treated with clear aligners and fixed appliances using cone beam computed tomography (CBCT).

Materials and methods

A total of 373 roots from 70 subjects, with similar baseline characteristics and the ABO discrepancy index scores (i.e., treatment difficulty), were included into two groups: the clear aligners group (Invisalign, Align Technology, California, USA) and fixed appliances group (Victory Series; 3 M Unitek, California, USA). Root length of each anterior tooth was measured on the CBCT images by two blinded investigators. The ARR on each tooth was calculated as the difference of root length before and after orthodontic treatment. Chi-square test and paired t test was used to compare the ARR between the two groups as well as before and after orthodontic treatments.

Results

Prevalence of ARR in the clear aligners group (56.30%) was significantly lower than that in the fixed appliances group (82.11%) (P < 0.001). The severity of ARR in the clear aligners group (0.13 ± 0.47 mm) was significantly less than that in the fixed appliances group (1.12 ± 1.34 mm) (P < 0.001). The most severe ARR was found on the maxillary canine (1.53 ± 1.92 mm) and lateral incisor (1.31 ± 1.33 mm) in the fixed appliances group; the least ARR was found on the mandibular canine (− 0.06 ± 0.47 mm) and lateral incisor (0.04 ± 0.48 mm) in the clear aligners group (P < 0.001).

Conclusions

The prevalence and severity of ARR measured on CBCT in patients with clear aligners were less than those in patients with fixed appliances.

Diagnostic efficacy of cone beam computed tomography in paediatric dentistry: a systematic review

Purpose

To determine in which clinical situations it is indicated or contra-indicated to prescribe cone beam computed tomography (CBCT) for paediatric patients.

Methods

Systematic review of in vivo paediatric research studies of diagnostic efficacy using CBCT, with supplementary searches for guideline documents on CBCT and for systematic reviews permitting inclusion of ex vivo and adult studies.

Results

After screening, 190 publications were included, mostly case studies. No systematic reviews were found of in vivo paediatric research. Fourteen studies of diagnostic efficacy were identified. The supplementary searches found 18 guideline documents relevant to the review and 26 systematic reviews. The diagnostic efficacy evidence on CBCT was diverse and often of limited quality. There was ex vivo evidence for diagnostic accuracy being greater using CBCT than radiographs for root fractures. The multiplanar capabilities of CBCT are advantageous when localising dental structures for surgical planning. Patient movement during scanning is more common in children which could reduce diagnostic efficacy.

Conclusions

No strong recommendations on CBCT are possible, except that it should not be used as a primary diagnostic tool for caries. Guidelines on use of CBCT in the paediatric age group should be developed cautiously, taking into account the greater radiation risk and the higher economic costs compared with radiography. CBCT should only be used when adequate conventional radiographic examination has not answered the question for which imaging was required. Clinical research in paediatric patients is required at the higher levels of diagnostic efficacy of CBCT.

Electronic supplementary material

The online version of this article (10.1007/s40368-019-00504-x) contains supplementary material, which is available to authorized users.

The Recommendation of Cone-beam Computed Tomography and Its Effect on Endodontic Diagnosis and Treatment Planning

INTRODUCTION

Although intraoral radiographs are foundational for diagnosis and planning treatment in dentistry, the resulting 2-dimensional image varies in interpretation requiring judgment. Cone-beam computed tomographic imaging provides a more detailed 3-dimensional image that may affect treatment recommendations. This study aimed to determine the basis for CBCT recommendations and the effect on diagnosis and treatment planning.

METHODS

The study involved a sample of 45 cases that presented for endodontic treatment, 30 with a CBCT scan on record and 15 without. For phase 1, all 45 cases were reviewed by 3 examiners without access to the CBCT scans. For phase 2, 4 months later, the 3 examiners reanalyzed the 30 cases, this time with the associated CBCT scan. Intra- and interexaminer agreements were recorded and analyzed. Also, the recommendations for CBCT were compared with the American Association of Endodontists/American Academy of Oral and Maxillofacial Radiology joint statement.

RESULTS

Interexaminer agreement in phases 1 and 2 was 65% and 72%, respectively. For endodontic diagnoses, there was a 19% change in the pulpal diagnosis category when CBCT imaging was added, whereas there was a 30% change in the apical category. The selections changed in 55% of the cases when determining etiology and in 49% of the cases when making recommendations. CBCT imaging was recommended 78.8% of the time when the case had a CBCT on record versus 33% of the time in cases without.

CONCLUSIONS

CBCT imaging has a significant effect in determining the etiology of endodontic pathoses and in recommending treatment. Furthermore, CBCT imaging is not overprescribed in the endodontic department, and the faculty members adhere to the American Association of Endodontists/American Academy of Oral and Maxillofacial Radiology recommendations.

Outcome of orthodontic treatment in subjects with periodontal disease. Part III: a CBCT study of external apical root resorption

Background

No evidence is present on the risk for external apical root resorption (EARR) during orthodontic treatment (OT) of adult patients with periodontal disease.

Aim

To examine EARR after OT in subjects with periodontal disease and to analyse how intrusion and change in inclination of the most proclined maxillary incisors influence EARR.

Methods

The study included 50 patients with periodontal disease. Sub-gingival debridement by ultrasonic instrumentation supplemented with hand instruments was performed by experienced dental hygienist after baseline examination for all patients. For the control group, final periodontal treatment (PT) was performed before orthodontic tooth movement. For the test group patients, final PT was performed after levelling and alignment phases were finished, before the active space closure with elastic chain and/or inter-arch elastic traction for sagittal correction was started. OT was performed with a straight-wire appliance. Micro-implants or implants were used for posterior anchorage. Cone beam computed tomography examinations were performed before and after OT. EARR of all single-rooted teeth were measured. EARR of the most proclined maxillary incisor was related to intrusion and change in inclination angle.

Results

EARR after OT was observed in median 80.7 per cent (interquartile range 22.02) of single-rooted teeth [mean 1.2 (standard deviation 0.44) mm]. In 82.3 per cent of teeth, EARR was 2 mm or less. Severe EARR was found in 8 per cent of patients and five maxillary incisors (less than 1 per cent of all teeth). The amount of intrusion and change in inclination angle of the most proclined maxillary central incisor influenced the extent of EARR. Mean EARR was significantly higher when OT lasted more than 18 months (P = 0.02).

Conclusions

OT in conjunction with PT in periodontal patients resulted in EARR in 81 per cent of all single-rooted teeth. Intrusion and change in inclination angle of the most proclined maxillary central incisor influenced the extent of EARR, as did longer OT.

Accuracy of Different Imaging CBCT Systems for the Detection of Natural External Radicular Resorption Cavities: An Ex Vivo Study

OBJECTIVE

The aim of this study was to compare the sensitivity and specificity of 3 different systems of cone-beam computed tomography (CBCT) in the detection of natural external root resorption (ERR) cavities using microtomography as the gold standard.

METHOD

A sample of 126 ex vivo teeth were submitted to a microtomography examination to verify the presence/absence of ERR cavities. Then, they were divided into the control group: 85 teeth that did not present with an ERR cavity; and experimental group: 41 teeth that presented with 1 or more ERR cavities. The size of the natural ERR cavities varied from 2.46 mm³ to 3.11 mm³, which corresponded to cavities of 1.67 mm and 1.81 mm in diameter, respectively. The teeth were placed on a dry human mandible for scanning in each of the 3 protocols with different voxel sizes: 0.25 mm, 0.20 mm, and 0.166 mm.

RESULTS

The accuracy of the 3 protocols evaluated in this study are listed in decreasing order: 60.3% for a voxel size of 0.20 mm, 56.7% for a voxel size of 0.166 mm, and 46.7% for a voxel size of 0.25 mm; these are smaller values than previous studies have obtained using artificial ERR cavities. Statistically significant results were not found among the 3 CBCT protocols that were used (P > .05), and the receiver operating characteristic curve shows the small differences found between the protocols.

CONCLUSION

The results indicate that CBCT presents, for natural ERR, lower sensitivity and specificity values than those detected in previous studies of artificial cavities. The results demonstrate that natural ERR is neither easily observed nor accurately located by CBCT, as previous studies using artificial ERR indicated.

The influence of bracket type on the external apical root resorption in class I extraction patients - a retrospective study

Background

The relationship between orthodontic treatment-related factors and EARR has never been fully answered. The aim of this study was to investigate whether conventional and passive self-ligating brackets affect the amount and severity of external apical root resorption (EARR) in withdrawal patients.

Methods

Ninety-eight patients were selected from department of orthodontic, hospital of stamotology, Wenzhou medical university. Patients received treatment with either a conventional edgewise appliance (n = 49, Mini, 3 M Unitek, USA) or a passive self-ligating bracket system (n = 49, Damon, Ormco, USA). EARR of the maxillary incisors was evaluated on panoramic radiographs at the before and end of orthodontic treatment, respectively. Intergroup comparisons of root resorption were performed with Mann-Whitney tests. The univariate and multivariate regression model was used to assess the appliance type, age, sex and duration of treatment on EARR.

Results

There was no significant difference in the amount of EARR between the two groups was found. Age and gender were not association with EARR, however, EARR was positively correlated with treatment duration.

Conclusions

The type of bracket did not influence the occurrence and severity of the external apical root resorption in class I extraction patients.

Diagnosis of external root resorption in teeth close and distant to zirconium implants: influence of acquisition parameters and artefacts produced during cone beam computed tomography

AIM

To assess the influence of artefacts, the metal artefact reduction (MAR) tool and kilovoltage (kVp) on the diagnosis of simulated external root resorption (ERR) in teeth close and distant to zirconium implants in cone beam computed tomography (CBCT) images.

METHODOLOGY

Cavities (0.62 mm in diameter and 0.19 mm deep) were created in the apical thirds of 12 roots on the buccal, lingual, distal or mesial surface; ten roots served as controls. The roots were randomly positioned in the first and second right and left premolar sockets of a dry human mandible, and a zirconium implant was placed in the socket of the first right molar. A ProMax 3D unit varying kVp (70, 80, or 90 kVp) and with the MAR tool activated or not was used to obtain CBCT scans. Five examiners evaluated all images to determine the area under the receiver operating characteristic (ROC) curve, sensitivity and specificity.

RESULTS

The ROC values and sensitivity were not affected by MAR or artefacts regardless of the distance to the implant (P > 0.05), whilst increasing kVp from 70 to 90 led to a significant increase in these values (P = 0.0202 and 0.0199, respectively). Specificity was not affected by the factors studied (P > 0.05).

CONCLUSIONS

Amongst the factors studied, only kVp influenced the diagnosis of simulated external root resorption in CBCT images. Increasing kVp from 70 to 90 improved the accuracy in diagnosing the simulated lesions.

Accuracy and reliability of tooth length measurements on conventional and CBCT images: An in vitro comparative study

CONTEXT

The purpose of this study was to evaluate the accuracy and reliability of tooth length measurements using conventional and cone-beam computed tomography (CBCT) imaging techniques.

AIM

The aim of this study was to assess the accuracy and reliability of various tooth length measurements made on CBCT scans and conventional imaging techniques [intraoral periapical radiograph (IOPA) and orthopantomogram (OPG)].

SETTINGS AND DESIGN

This is an in-vitro comparative study.

SUBJECTS AND METHODS

In total, 50 extracted single-rooted premolar teeth were mounted on the dry human mandible. For each extracted tooth, measurements for tooth length, crown length, and root lengths were taken with a Vernier caliper and using three imaging modalities: CBCT, OPG, and IOPA radiographs. The measurements were compared with the gold standard (Vernier caliper).

STATISTICAL ANALYSIS USED

One-way analysis of variance was used to compare mean values between the groups that are Vernier caliper, CBCT, IOPA, and OPG. The multiple comparisons of means of tooth length, root length, and crown length were done by Bonferroni test.

RESULTS

A significant difference in the tooth length measurements was seen between the measurements taken by CBCT and IOPA and between IOPA and OPG. But, no significant difference was seen between any other groups. The highly significant difference was seen between the root length measurements taken by IOPA and OPG and by CBCT and OPG. However, no significant difference was seen between any other groups. No significant difference was seen in between the crown length measurements taken by Vernier caliper and CBCT and between IOPA and OPG. However, a significant difference was seen between all the groups.

CONCLUSIONS

Among the radiographic techniques, CBCT was found to be the most accurate in measuring the tooth, root, and crown lengths.

Apical root displacement is a critical risk factor for apical root resorption after orthodontic treatment

OBJECTIVES:

To identify risk factors for apical root resorption (ARR) of maxillary and mandibular incisors using mathematical quantification of apical root displacement (ARD) and multiple linear mixed-effects modeling.

MATERIALS AND METHODS:

Periapical radiographs of maxillary and mandibular incisors and lateral cephalograms of 135 adults were taken before and after orthodontic treatment. ARR was measured on the periapical radiographs, and movement of central incisors was evaluated on the superimposed pre- and posttreatment lateral cephalograms. ARD was mathematically calculated from pretreatment tooth length, inclination change, and movement of the incisal edge. Linear mixed-effects model analysis was performed to identify risk factors for ARR, and standardized coefficients (SCs) were calculated to investigate the relative contribution of the risk factors to ARR.

RESULTS:

Vertical ARD showed the highest SCs for both maxillary and mandibular incisors. Horizontal ARD showed the second highest SC for mandibular incisors but was not significantly correlated with the ARR of maxillary incisors. When horizontal and vertical ARDs were included in the mixed-effects model, the use of self-ligating brackets was significantly correlated with increased ARR of mandibular incisors.

CONCLUSIONS:

ARD is a critical factor for ARR after orthodontic treatment. Careful monitoring of ARR is recommended for patients requiring significant ARD of incisors.

Knowledge of orthodontic tooth movement through the maxillary sinus: a systematic review

BACKGROUND

To investigate the feasibility, safety and stability of current interventions for moving teeth through the maxillary sinus (MTTMS) by performing a systematic review of the literature.

METHODS

The electronic databases PubMed, Embase, CENTRAL, Web of Science, CBM, CNKI and SIGLE were searched without a language restriction. The primary outcomes were parameters related to orthodontic treatment, including orthodontic protocols, magnitude of forces, type of tooth movement, duration and rate of tooth movement, and remolding of alveolar bone and the maxillary sinus floor. The secondary outcomes were safety and stability, including root resorption, perforation of the sinus floor, loss of pulp vitality and periodontal health and relapse.

RESULTS

Nine case reports with 25 teeth were included and systematically analyzed. Fifty to two hundred g of force was applied to move teeth through the maxillary sinus. Bodily movement was accomplished, but initial tipping was observed in 7 cases. The rate was 0.6-0.7 mm/month for molar intrusion and 0.16-1.17 and 0.05-0.16 mm/month for mesial-distal movement of premolars and molars, respectively. Bone formation and remolding of the sinus floor occurred in 7 cases. Root resorption within 6 to 30 months was observed in 3 cases, while no cases of perforation of the sinus floor, loss of pulp vitality, periodontal health impairment or relapse were reported.

CONCLUSIONS

At the present stage, no evidence-based protocol could be recommended to guide MTTMS. The empirical application of constant and light to moderate forces (by TAD, segment and multibrackets) to slowly move teeth through or into the maxillary sinus in adults appears to be practical and secure. Bodily movement was accomplished, but teeth appear to be easily tipped initially, potentially resulting in root resorption. However, this conclusion should be interpreted with caution as the currently available evidence is based on only a few case reports or case series and longitudinal or controlled studies are lacking in this area.

CBCT assessment of radicular volume loss after rapid maxillary expansion: A systematic review

Background

The present systematic review analyzed the current literature to investigate whether rapid maxillary expansion (RME) causes radicular resorption, assessed by cone-beam computed tomography (CBCT).

Material and Methods

Eighteen electronic databases and reference lists of studies were searched up to November 2017. Grey literature was also screened. To be included, articles must be human studies on growing subjects with transversal maxillary deficiency treated with maxillary expansion protocol and with 3-D radiographic assessment of radicular volume by CBCT images. Two authors independently performed study selection, data extraction, and risk of bias assessment. Study characteristics (study design, sample size, age, sex, skeletal maturity, type of appliance, daily activation, teeth evaluated, CBCT settings), and study outcomes (radicular volume loss) were reported according to the PRISMA statement.

Results

Only 3 articles were considered eligible and an individual analysis of the selected articles was undertaken. The risk of bias assessment revealed low methodological quality for all the studies included. In all the considered studies, significant radicular volume loss was observed in posterior teeth, following RME. When reported in percentage, the radicular volumetric loss was similar between anchored (first molars and first premolars) and unanchored teeth (second premolars).

Conclusions

A preliminary evaluation of the patient-related risk factors for RR is warmly advisable when administering RME.

Key words:RME, maxillary expansion, root resorption, external root resorption.

External apical root resorption diagnosis by using FII human dentine fraction and salivary IGg

BACKGROUND

External apical root resorption as a consequence of orthodontic treatment is an inflammatory pathological process that results in permanent loss of tooth structure from the root apex.

OBJECTIVES

This study aimed to investigate the diagnostic potential of human dentine fractions and salivary IgG in external apical root resorption.

PATIENTS AND METHODS

Saliva samples were collected from 10 patients before (T0) and after 3 (T3), 6 (T6) and 12 (T12) months of orthodontic treatment. The total dentinal extract, obtained from human third molars, was fractioned by gel filtration chromatography in three fractions denominated FI, FII and FIII. The root resorption analysis of the upper central incisors was performed by digital image subtraction method. Reactivity of salivary IgG to antigenic fractions of dentine was determined by enzyme-linked immunosorbent assay (Elisa).

RESULTS

Regardless of treatment, FI dentin fraction with high MM (<300kDa) was the one that presented highest reactivity with salivary IgG. However, it was found higher salivary IgG reactivity for FII (69 to 45 kilodalton [kDa]) as compared to FIII (<45kDa) at (T6) and (T12), (P<0.05), the same periods in that the root resorptions were detected.

CONCLUSION

Our results suggest that FII human dentine fraction and salivary IgG have potential to be used in diagnosis and monitoring of external apical root resorption. The development of a practical and accessible biochemical test using saliva and FII dentine fraction may help in the prevention of severe root resorption.

External apical root resorption in non-extraction cases after clear aligner therapy or fixed orthodontic treatment

Background/purpose

The application of removable aligner in orthodontic treatment has increased rapidly in recent years, while its effects on root resorption remains unclear. The aim of this study was to comparatively evaluate the amount of external apical root resorption (EARR) in non-extraction patients receiving clear aligner therapy (CAT) or fixed orthodontic treatment (FOT).

Materials and methods

Eighty non-extraction patients treated with CAT or FOT exclusively were evaluated retrospectively. Panoramic radiographs were used to measure the length of crowns and roots of the incisors before and after treatment. The amount of EARR was determined by the relative change of root-crown ratio and compared between the two groups. The potential predictive factors of EARR were investigated using spearman correlation analysis.

Results

The overall EARR in the CAT patients was significantly less than the FOT. Similar results were observed in maxillary central incisors, maxillary lateral incisors, mandibular central incisors and mandibular lateral incisors. The duration of treatment positively correlated with the amount of EARR in both modalities. Gender, age, skeletal pattern or degree of malocclusion did not affect the occurrence of EARR.

Conclusion

Clear aligner therapy may have a superiority of reducing external apical root resorption compared to fixed orthodontic treatment in non-extraction patients.