Three-dimensional assessment of alveolar bone changes and root resorption in extraction patients after fixed orthodontic treatment: A prospective study

BACKGROUND

The aim of this study was to evaluate the alveolar crestal bone height, alveolar bone thickness, and root resorption in mandibular incisors after fixed orthodontic treatment.

METHODS

A total of 35 patients (mean age 17.02 ± 3.24 years) with moderate to severe mandibular anterior crowding requiring first premolar extraction were included. Cone beam computed tomography scans of the mandibular anterior region were obtained from the patients before and after orthodontic treatment. The alveolar crestal bone height, cortical bone thickness (CBT) (at apex and midroot level), labial and lingual alveolar bone thickness, and root resorption were assessed for all mandibular incisors. Paired Student's t test was used to compare pretreatment and post-treatment alveolar bone changes and root resorption.

RESULTS

A significant decrease in lingual crestal bone height was observed in all mandibular incisors after orthodontic treatment (P < 0.001). Lingual CBT decreased at the midroot level significantly for all mandibular incisors after completion of orthodontic treatment (P < 0.001). A significant decrease in total lingual bone thickness was observed in all mandibular incisors (P < 0.001). Root lengths of mandibular incisors decreased significantly in the sagittal and coronal sections after orthodontic treatment (P < 0.001).

CONCLUSIONS

Fixed orthodontic treatment with premolar extraction results in a significant reduction of alveolar crestal bone height, CBT (at midroot level), and alveolar bone thickness on the lingual aspect of mandibular incisors. Significant orthodontically induced inflammatory root resorption was observed in all mandibular incisors after orthodontic treatment.

Does maxillary sinus proximity affect molar root resorption during distalization using Invisalign? a CBCT study

BACKGROUND

This study aimed to assess the correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption during molar distalization using clear aligner therapy (CAT).

MATERIALS AND METHODS

Thirty-eight cone beam computed tomography scans (CBCTs) obtained pre- (T0) and post-treatment (T1) from 19 adult patients (36.68 ± 13.50 years), who underwent maxillary molar distalization using Invisalign® aligners (Align Technology, Inc., San José, CA, USA) with a minimum of 2 mm distalization, were evaluated in this study At least 22 h of aligner wear per day was a main inclusion criterion. Sinus proximity and changes in root lengths were measured for 61 molars (183 roots). Spearman coefficient analysis was used for assessing correlation between sinus proximity and root resorption. The level of significance was set at p ≤ 0.05. The reproducibility of measurements was assessed by intraclass correlation coefficient (ICC).

RESULTS

Spearman coefficient revealed no significant correlation between sinus proximity and molar root resorption for mesiobuccal, distobuccal or palatal roots (p = 0.558, p = 0.334, p = 0.931, respectively).

CONCLUSION

There was no correlation between maxillary sinus proximity to root apices of maxillary molars and root resorption.

Performance of the Malmgren Index for Assessing Root Resorption on 2D vs. 3D Radiographs: A Pilot Study

OBJECTIVES

To compare the performance of the Malmgren index on 2D and 3D radiographs.

METHODS

Patients with a panoramic radiograph and a cone beam computed tomography (CBCT) taken at an interval of <3 months and presenting root resorption (RR) on at least one incisor and/or canine were retrospectively included. RR was scored twice by two observers using the Malmgren index in both the 2D and 3D sets, and intra-class correlation coefficient (ICC) was calculated.

RESULTS

155 teeth were analyzed. The ICC was the lowest in 2D, followed by overall, transversal and sagittal 3D. Malmgren scores were systematically higher in 2D, which overestimated RR, especially in the transversal plane on all incisors and canines and in the sagittal plane on the maxillary incisors. 2D respectively leads to 28.0-34.8% of false positives and negatives when discriminating between RR or not. The early stages of RR are often misdiagnosed in 2D, while later stages are more accurate.

CONCLUSIONS

The original Malmgren index is not suited for 3D images, especially axial, where using dichotomized values (resorption yes/no) leads to overestimation of RR. A low-dose CBCT of the upper incisors could detect RR with high diagnostic accuracy in the early stages of orthodontic treatment, especially in patients with dental trauma or familial RR history.

Volumetric cone-beam computed tomography evaluation and risk factor analysis of external apical root resorption with clear aligner therapy

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.

Does mini-implant-supported rapid maxillary expansion cause less root resorption than traditional approaches? A micro-computed tomography study

OBJECTIVE

This study aimed to evaluate the volume, amount, and localization of root resorption in the maxillary first premolars using micro-computed tomography (micro-CT) after expansion with four different rapid maxillary expansion (RME) appliances.

METHODS

In total, 20 patients who required RME and extraction of the maxillary first premolars were recruited for this study. The patients were divided into four groups according to the appliance used: miniimplant- supported hybrid RME appliance, hyrax RME appliance, acrylic-bonded RME appliance, and full-coverage RME appliance. The same activation protocol (one activation daily) was implemented in all groups. For each group, the left and right maxillary first premolars were scanned using micro-CT, and each root were divided into six regions. Resorption craters in the six regions were analyzed using special CTAn software for direct volumetric measurements. Data were statistically analyzed using Kruskal-Wallis one-way analysis of variance and Mann-Whitney U test with Bonferroni adjustment.

RESULTS

The hybrid expansion appliance resulted in the lowest volume of root resorption and the smallest number of craters (p < 0.001). In terms of overall root resorption, no significant difference was found among the other groups (p > 0.05). Resorption was greater on the buccal surface than on the lingual surface in all groups except the hybrid appliance group (p < 0.05).

CONCLUSIONS

The findings of this study suggest that all expansion appliances cause root resorption, with resorption craters generally concentrated on the buccal surface. However, the mini-implant-supported hybrid RME appliance causes lesser root resorption than do other conventional appliances.

Accuracy of Root ZXII, E-PEX and FIND apex locators in teeth with vital pulp: an in vivo study

This research evaluated, in vivo, the accuracy of three electronic apex locators - EALs (Root ZXII, E-PEX and FIND) in teeth with vital pulp submitted to biopulpectomy, preserving the periodontal stump. For this study, 90 single-rooted teeth with extraction indication were selected. After positive pulpal cold sensitivity test, pulp chamber access was performed. The cervical and middle thirds of root canals were instrumented with Reciproc R25, and the K#15 file was used as a standard instrument to determine working length, forming 2 groups: Constriction (insertion of the instrument until the apical constriction limit) and Foramen (insertion of the instrument until the foramen and then repositioning at constriction, without removing the file from the canal). The hand file was stabilized with a light-cured flow resin. After extraction, the samples were analyzed through microCT SkyScan 1272, with CTAN software, which evaluated the proximity between the tip of the file to the apical constriction, providing data for comparative analysis using Kruskal-Wallis and Dunn tests (p<0.05). There was a statistically significant difference in the abilities of the EALs to detect the apical constriction after reaching the foramen with Root ZX II showing higher accuracy (89%). However, there was no difference in the accuracy of the three EALs in detecting the apical constriction without reaching the foramen. Based on the present results, we conclude that EALs may show accurate measures in detecting apical constriction and foramen, even without damaging the periodontal stump in biopulpectomy.

The Radiological Assessment of Root Features and Periodontal Structures in Endodontically Treated Teeth Subjected to Forces Generated by Fixed Orthodontic Appliances. A Prospective, Clinical Cohort Study

The various side effects of orthodontic treatment with fixed orthodontic appliances (FOAs) and their impact on apical and periodontal structures have been widely reported. However, the existing data is not yet conclusive. Aims and objectives: To investigate the status of roots and periodontium in endodontically treated teeth that have undergone orthodontic treatment with the use of FOAs and to evaluate their impact on apical/periodontal structures. Material and methods: The prospective clinical cohort study initially involved 69 participants aged 16–40, without underlying systemic conditions, who received orthodontic treatment with ligatureless FOA systems due to different types of mild and moderate malocclusions. To meet the required criteria, 88 teeth in 34 patients were assessed clinically and radiologically. Participants had at least one tooth treated endodontically while the corresponding tooth from the same anatomical group on the opposite side was vital and intact (a ‘split-mouth’ approach). Four cohorts were allocated: Group IA consisted of 15 teeth, treated utilising the principles of modern endodontics, that were subjected to orthodontic forces no less than six months after completing the root canal obturation. Group I consisted of 13 similarly endodontically treated teeth, which commenced orthodontic treatment at least six months after the completed endodontic therapy. Group II contained 16 teeth treated by conventional endodontic methods and the control group, Group III, contained 44 clinically and radiologically intact teeth (incisors and premolars) with vital and sound dental pulp. The response of apical and periodontal structures to FOAs was determined by data collected from intraoral periapical radiographs taken within the course of five consecutive appointments during the orthodontic treatment. Results: No statistically significant differences were observed in susceptibility to FOA-induced external apical root resorption (EARR) between combined Groups IA + IB and II. An association was, however, demonstrated, between the occurrence of EARR and the degree of expansion of the periodontal ligament (PDL) space, regardless the method of root canal treatment. Cumulative data revealed a positive correlation between the width of the PDL space and the stage of FOA treatment (the third and the fourth appointment). The subtle changes in radiological length of roots have been observed (min 0 mm/max 0.38 mm), particularly between the second and third appointment in Group II (p < 0.05). Conclusions: The standard orthodontic therapy with FOAs is a safe option with predictable outcome for persons who have recently received endodontic therapy. The anterior teeth, predominantly incisors, were more susceptible to minimal EARR than premolars, which suggests that the rate of EARR occurrence may depend upon the original morphology of the apical portion of the root. The use of additional orthodontic forces increases the risk of EARR and is associated with a higher incidence of radiologically detected PDL space widening.

Does the rhythm and appliance type of rapid maxillary expansion have an effect on root resorption?

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.

Effect of micro-osteoperforations on external apical root resorption: A randomized controlled trial

Objective

This study aimed to investigate the effect of micro-osteoperforations (MOPs) on external apical root resorption (EARR) during the initial orthodontic alignment phase of maxillary anterior crowding.

Methods

Thirty patients (25 females, 5 males; mean age, 22.66 ± 3.27 years) who presented with moderate crowding of the upper labial segment and underwent extraction-based fixed appliance treatment were recruited. They were randomly allocated to receive adjunctive therapy with MOPs (n = 15) or treatment with fixed appliances only (control group; n = 15). EARR was measured from long-cone periapical radiographs taken at the start and the sixth month of treatment. A correction factor for the enlargement difference was used to calculate EARR. Data were analyzed with descriptive statistics and repeated-measures analysis of variance.

Results

The mean root lengths of 168 teeth were measured and showed no statistically significant difference (p > 0.05) after six months of fixed appliance treatment in the MOP (mean difference [MD] = 0.13 mm; 95% confidence interval [CI] = −0.10–0.35) and control group (MD = 0.14 mm; 95% CI = −0.10–0.37). Most of the roots in the MOP and control groups (42.86% and 52.38%, respectively) showed only mild resorption. Less than 8% of the roots in both groups (7.14% in the MOP group and 4.76% in the control group) showed moderate resorption.

Conclusions

Acceleration of orthodontic tooth movement with adjunctive MOPs therapy during the alignment phase does not exacerbate EARR in patients with moderate crowding of the upper labial segment in comparison with controls.

Effects of systemic medication on root resorption associated with orthodontic tooth movement: a systematic review of animal studies

BACKGROUND

Theoretically, root resorption could be modulated by any medication taken that exhibits possible effects on the implicated molecular pathways.

OBJECTIVES

To systematically investigate and appraise the quality of the available evidence from animal studies, regarding the effect of commonly prescribed systemic medication on root resorption associated with orthodontic tooth movement.

SEARCH METHODS

Search without restrictions in eight databases (PubMed, Central, Cochrane Database of Systematic Reviews, SCOPUS, Web of Science, Arab World Research Source, ClinicalTrials.gov, ProQuest Dissertations and Theses Global) and hand searching until April 2018 took place. One author developed detailed search strategies for each database that were based on the PubMed strategy and adapted accordingly.

SELECTION CRITERIA

Controlled studies investigating the effect of systemic medications on root resorption associated with orthodontic tooth movement.

DATA COLLECTION AND ANALYSIS

Following study retrieval and selection, relevant data were extracted and the risk of bias was assessed using the SYRCLE's Risk of Bias Tool.

RESULTS

Twenty-one studies were finally identified, most of which at unclear risk of bias. Root resorption was shown to increase in Vitamin C treated animals in comparison with the control group, whereas a comparative decrease was noted after the administration of the alendronate, ibuprofen, growth hormone, low doses of meloxicam, simvastatin, lithium chloride and strontium ranelate. No difference was noted for acetaminophen, aspirin, fluoxetine, atorvastatin, misoprostol, zoledronic acid and zinc. Finally, inconsistent effects were observed after the administration of celecoxib, prednisolone and L-thyroxine. The quality of the available evidence was considered at best as low.

CONCLUSIONS

The pharmaceutical substances investigated were shown to exhibit variable effects on root resorption. Although the overall quality of evidence provides the clinician with a cautious perspective on the strength of the relevant recommendations, good practice would suggest that it is important to identify patients consuming medications and consider the possible implications.

REGISTRATION

PROSPERO (CRD42017078208).

Effects of micro-osteoperforations on intraoral miniscrew anchored maxillary molar distalization : A randomized clinical trial

PURPOSE

The aim was to study the effects of micro-osteoperforations (MOPs) on miniscrew-supported maxillary molar distalization.

METHODS

As part of a single center, split-mouth, randomized clinical trial, 20 eligible subjects were randomly recruited from patients who had applied to the orthodontics department of a university dental hospital. In the experimental group, subjects were randomized to receive MOPs to either the left or right maxillary molar region (n = 10). The control group (n = 10) and the contralateral sides of the experimental group (n = 10) did not receive any MOPs. In both groups, distalization of the maxillary molars was performed by miniscrew-supported distalization appliances. Using 3D models, maxillary molar distalization at 3, 6, 9, and 12 weeks was measured. Pain, discomfort, eating difficulty, and speech problem levels were assessed using a visual analog scale (VAS 0-10). Periodontal evaluations were performed.

RESULTS

In all, 18 subjects completed the study. The mean amount of tooth movement was significantly greater on the MOP side compared to contralateral side of the experimental group at all time points. After 12 weeks, the maxillary molars on the MOP side moved 1.17-fold more than those on the contralateral side. No significant differences were found regarding amount of tooth movement between the control group and the MOP and contralateral sides of the experimental group. The rates of tooth movement in the MOP sides of the experimental group, contralateral sides of the experimental group, and the control group were 0.029, 0.025, and 0.028 mm/day, respectively. Pain VAS scores after intervention were significantly increased on the MOP side compared with the contralateral side of the experimental group but not at any other time point. No differences in periodontal scores between the groups were observed.

CONCLUSIONS

A 1.17-fold increase in the rate of tooth movement in the MOP group compared with the contralateral side was recorded. However the accelerating effect of MOPs was lower than expected. The mean pain level was statistically greater in the MOP group compared to the contralateral side only on the first day of application.

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.

A randomized clinical trial of the effectiveness of 0.018-inch and 0.022-inch slot orthodontic bracket systems: part 3-biological side-effects of treatment

OBJECTIVE

To compare orthodontically induced inflammatory root resorption (OIIRR) and patient perception of pain during orthodontic treatment between 0.018-inch and 0.022-inch slot bracket systems.

SUBJECTS AND METHODS

Eligible participants aged 12 years or above were allocated to treatment with the 0.018-inch or 0.022-inch slot MBT appliance (3M Unitek, Monrovia, California, USA) using block randomization in groups of 10. OIIRR was assessed radiographically using standardized periapical radiographs before and after 9 months from the start of treatment. Patient perception of pain was assessed using a validated patient questionnaire at 6 months from the start of treatment. Parametric tests (t-test) and non-parametric tests (chi-square with Fisher's exact tests and Kruskal-Wallis test) assessed differences between the groups (P < 0.05). The correlation between severity of OIIRR and abnormal root morphology, history of dental trauma, and pain during treatment was assessed.

RESULTS

Of the 187 participants randomized (1:1 ratio), 34 withdrew or were excluded (protocol deviations or poor cooperation). There were 77 patients in the 0.018-inch slot group and 76 patients in the 0.022-inch slot group (overall mean age: 19.1 years). Baseline characteristics were similar between groups (P > 0.05). There was no significant difference in the severity of the OIIRR nor patient perception of pain between the two study groups (P = 0.115 and P = 0.08 respectively). The correlation between the severity of OIIRR and abnormal root morphology or history of dental trauma was not statistically significant (P = 0.086 and P = 0.313). Moreover, there was no significant correlation between the severity of OIIRR and pain during treatment (R = 0.045, P = 0.617).

LIMITATIONS

It was impossible to blind clinicians or patients to allocation, and oral hygiene and periodontal outcomes were not assessed.

CONCLUSIONS

The effect of bracket slot size on the severity of OIIRR and patient perception of pain are not significant.

TRIAL REGISTRATION

The trial was registered with ClinicalTrials.gov on 5 March 2014, registration number: NCT02080338.

Orthodontic mechanotherapies and their influence on external root resorption: A systematic review

INTRODUCTION

This systematic review assesses the literature regarding the association between orthodontic tooth movement and external root resorption. By determining the evidence level supporting the association, the results could provide clinical evidence for minimizing the deleterious effect of orthodontic tooth movement.

METHODS

Electronic databases, including MEDLINE, PubMed, Embase, Scopus, CINAHL, Cochrane Library, and LILACS, were searched up to February 2018, with hand searching of selected orthodontic journals undertaken to identify any preelectronic publications. Searches were undertaken with no restrictions on year, publication status, or language. Selection criteria included randomized controlled trials conducted with the use of fixed orthodontic appliances or sequential thermoplastic aligners on human patients. The quality of included studies was assessed with the use of the Cochrane Risk of Bias Tool and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Inter-rater agreement of the review authors was used for the inclusion of primary articles, risk of bias assessment, and evaluation of the quality of evidence (GRADE), and it was calculated with the use of the Cohen kappa statistic.

RESULTS

A total of 654 articles were retrieved in the initial search. After the review process, 25 articles describing 24 individual trials met the inclusion criteria. Sample sizes ranged from 6 to 154 patients. Most articles were classified as having unclear risks of bias and very low to low quality of evidence.

CONCLUSIONS

There is very low to low evidence for supporting positive associations between root resorption and increased force levels, force continuity, intrusive forces, and treatment duration. Moreover, by including a pause in treatment for patients experiencing root resorption, it may be possible for the clinician to reduce the severity of the condition. Of the included studies, the most common methodologic flaws include the absence of a control group, appropriate randomization strategy, and adequate examinations before and after treatment.

Orthodontically induced cervical root resorption in humans is associated with the amount of tooth movement

Introduction

The aim of this study was to investigate the variation in the amount of the orthodontically induced cervical root resorption and the association with several factors, such as the amount of tooth displacement, location of tooth in the maxilla or mandible, and presence of an interference that may influence the amount of root resorption.

Subjects and methods

This study included 30 subjects (20 females, 10 males) with an age range of 11.3 to 43.0 years. Using a standardized experimental orthodontic tooth movement, 59 premolars were moved buccaly during 8 weeks with application of 1 N force. Fifty-eight contralateral premolars not subjected to orthodontic tooth movement served as controls. At the end of the experimental period the teeth were carefully extracted, scanned in a micro-computed tomography scanner with a resolution of 9 µm, and the reconstructed images were processed for volumetric evaluation of resorption craters at the cervical part of the root surface. Data were analyzed using unpaired t-test and the Pearson's correlation.

Results

Higher amount of cervical root resorption was detected in the orthodontically moved teeth (0.00055 mm3) compared to controls (0.00003 mm3; P < 0.001). Moderate correlation was found between root resorption in the two experimental teeth within the same individual (R = 0.421, P = 0.023). Teeth located in the mandible presented more resorption than those in the maxilla (P = 0.046). The amount of root resorption was correlated to the amount of tooth movement (R = 0.318, P = 0.016).

Conclusion

Application of a 1 N force over a 2-month period provokes severe root resorption at the compression cervical sites. Resorption is correlated with the amount of tooth movement and the location of the teeth.

Volumetric evaluation of root resorption on the upper incisors using cone beam computed tomography after 1 year of orthodontic treatment in adult patients with marginal bone loss

OBJECTIVES:

To determine upper incisor root resorption, volume loss, and the relationship between root volume loss and tooth movement after 1 year of orthodontic treatment in patients with marginal bone loss.

MATERIALS AND METHODS:

A total of 30 women (46.3 ± 5.4 years old) with moderate upper incisor bone loss who required intrusion during orthodontic treatment were recruited. Pre- and post-treatment cone beam computed tomography images were reconstructed. Upper incisors at pre- and post-treatment were superimposed; labio- and palato-apical, middle, and coronal third root volumes were assessed. Tooth movement and alveolar bone height were measured from lateral cephalometric radiographs and cone beam computed tomography. Changes in root volume/alveolar bone height were compared using paired-sample t-tests, percentage root volume loss for each tooth/segment was evaluated by one-way analysis of variance, and the relationship between percentage root loss and degree of tooth movement was assessed by linear regression.

RESULTS:

Mean root volume significantly decreased on the labio- and palato-apical aspects of 12 and labio-apical aspects of 21 and 22 ( P ≤ .024). Palato-apical segment volume loss was greater on lateral than central incisors ( P ≤ .016). Two-dimensional root length and cementoenamel junction-bone crest distance did not change between T0 and T1, with no significant relationship between tooth movement amount and percentage root volume loss.

CONCLUSIONS:

Delivery of 40 g intrusive force to the four upper incisors using a T-loop and the leveling phase lead to more apical root volume loss on lateral than central incisors. There was no relationship between extent of tooth movement and upper incisor root volume loss.

Three-dimensional assessment of the effect of micro-osteoperforations on the rate of tooth movement during canine retraction in adults with Class II malocclusion: A randomized controlled clinical trial

INTRODUCTION

The purpose of this split-mouth trial was to investigate the effect of micro-osteoperforations (MOPs) on the rate of tooth movement.

METHODS

Thirty-two patients (24 female, 8 male; mean age, 19.26 ± 2.48 years) who required fixed orthodontic treatment and maxillary first premolar extractions participated in this trial with MOPs randomly allocated to either the right or left sides distal to the maxillary canines. Eligibility criteria included Class II Division 1 malocclusion, healthy periodontal condition, no smoking, and no systemic disease. Miniscrews were used to support anchorage and retract the canines with the aid of closed-coil nickel-titanium springs with 150 g of force. Randomization was accomplished with block randomization with a permuted block size of 2 with a 1:1 allocation ratio to either right or left with allocations concealed in opaque, sealed envelopes. Blinding was used at the data collection and analysis stages. Three MOPs were performed using miniscrews (5 mm depth, 1.5 mm width) on the buccal bone distal to the canines on the randomly selected side. The primary outcome was the rate of canine retraction measured from 3-dimensional digital models superimposed at the rugae area from the baseline to the first, second, and third months. The following secondary outcomes were examined: anchorage loss, canine tipping, canine rotation, root resorption, plaque index, and gingival index. Pain level, pain interference with the patients' daily life, patients' satisfaction with the procedure and degree of ease, willingness to repeat the procedure, and recommendation to others were also evaluated.

RESULTS

There was no statistically significant difference in the rates of tooth movement between the MOP and the control sides at all time points (first month: P = 0.77; mean difference, 0.2 mm; 95% CI, -0.13, 0.18 mm; second month: P = 0.50; mean difference, -0.08 mm; 95% CI, -0.33, 0.16 mm; third month: P = 0.76; mean difference, -0.05 mm; 95% CI, -0.40, 0.29 mm). There were also no differences in anchorage loss, rotation, tipping, root resorption, plaque index, periodontal index, and pain perception between the MOP and control sides at any time point (P >0.05). MOPs had no effect on the patients' daily life except for a feeling of swelling on the first day (P = 0.05). Level of satisfaction and degree of easiness of the procedure were high. A significant percentage of patients were willing to repeat the procedure and recommend it to others. No serious harm was observed.

CONCLUSIONS

Three MOPs were not effective in accelerating tooth movement at any time point. Other secondary parameters evaluated were not different between the MOP and control sides except for the feeling of swelling on day 1 on the MOP side. Patients were highly satisfied with the MOP procedure, and many considered MOPs an easy procedure and were willing to repeat and recommend it to friends.

REGISTRATION

This trial was registered at Clinicaltrials.gov with identifier number NCT02473471.

PROTOCOL

The protocol was not published before trial commencement.

FUNDING

This work was supported by Jordanian University of Science and Technology (grant number 20150263). No conflict of interest is declared.

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

OBJECTIVE

To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) and periapical radiographs (PR) for the detection of external root resorption (ERR).

MATERIAL AND METHODS

An electronic search in databases, including the Cochrane Central Register of Controlled Trials, PubMed, Embase, the China National Knowledge Infrastructure, and System for Information on Grey Literature in Europe (SIGLE), was performed until August 2016. A manual search of relevant journals and reference lists of enrolled studies was conducted. The studies investigating the diagnostic accuracy of CBCT or PR for ERR, with simulated ERR as the reference test, were considered eligible. The diagnostic accuracy of CBCT and PR was statistically pooled using a bivariate model. Meta-regression and subgroup analysis were performed to explore the sources of heterogeneity. Sensitivity analysis was used to test the stability of the overall results in the meta-analysis.

RESULTS

A total of 15 studies were included in this systematic review. The pooled results showed that CBCT had significantly higher sensitivity (0.89; 95% confidence interval [CI]: 0.77-0.96) and area under curve (0.96; 95% CI: 0.77-0.96) than PR (sensitivity: 0.68; 95% CI: 0.56-0.78; area under curve: 0.88; 95% CI: 0.85-0.90). No difference in sensitivity, specificity, and area under the curve between conventional and digital PR was observed.

CONCLUSIONS

Currently available evidence suggests that CBCT could be reliable to detect the presence of ERR in clinical practice and has a higher diagnostic efficacy than PR.

Effect of low-intensity pulsed ultrasound on orthodontically induced root resorption caused by torque: A prospective, double-blind, controlled clinical trial

Objectives: 

To evaluate the effects of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced tooth root resorption caused by torque in human subjects.

Materials and Methods: 

Ten healthy patients (12–35 years of age) who required extraction of all first premolars as a part of their routine orthodontic treatment were recruited. A 15° twist was applied in the arch wire using 0.019 × 0.025-inch TMA in a 0.022-inch bracket system (Synergy R) that produced a buccal root torque of approximately 5 N/mm at the bracket level. Using a split mouth design, randomization, and blinding, one side of the arch received LIPUS for 20 minutes per day for 4 weeks at an incident intensity of 30 mW/cm2 of the transducers’ surface area. The other side served as a self-control, which received a sham transducer. After 4 weeks, all first premolars were extracted and micro–computed tomographic analysis was performed on these extracted teeth. A linear mixed-model statistical analysis was used.

Results: 

LIPUS-treated teeth showed significantly less total volume of resorption lacunae compared to control teeth by a mean difference of (0.54 ± 0.09 mm3) (P &lt; .001) and percentage of root resorption by a mean difference of (0.33 ± 0.05 mm3) (P &lt; .001). In addition, significantly fewer resorption lacunae were found on all root surfaces in the LIPUS group compared to the control except in the instance of the distal surface.

Limitations: 

This study was performed on limited number of cases during a 4-week period.

Conclusions: 

LIPUS minimizes root resorption when applied during torque tooth movement over a 4-week period.

Association of orthodontic force system and root resorption: A systematic review

INTRODUCTION

In this systematic review, we assessed the literature to determine which evidence level supports the association of orthodontic force system and root resorption.

METHODS

PubMed, Cochrane, and Embase databases were searched with no restrictions on year, publication status, or language. Selection criteria included human studies conducted with fixed orthodontic appliances or aligners, with at least 10 patients and the force system well described.

RESULTS

A total of 259 articles were retrieved in the initial search. After the review process, 21 full-text articles met the inclusion criteria. Sample sizes ranged from 10 to 73 patients. Most articles were classified as having high evidence levels and low risks of bias.

CONCLUSIONS

Although a meta-analysis was not performed, from the available literature, it seems that positive correlations exist between increased force levels and increased root resorption, as well as between increased treatment time and increased root resorption. Moreover, a pause in tooth movement seems to be beneficial in reducing root resorption because it allows the resorbed cementum to heal. The absence of a control group, selection criteria of patients, and adequate examinations before and after treatment are the most common methodology flaws.

Apical root resorption: the dark side of the root

INTRODUCTION

The diagnosis of apical root resorption is usually based on routine radiographs. However, these methods are limited because the images reflect the superimposition of the whole root structure and can lead to underestimation of the extent of apical root resorption. In this study, we aimed to determine the lengths of the labial and lingual surfaces of incisors with apical root resorption and compare them with the longest radicular length obtained on sagittal images of cone-beam computed tomography, and to create a qualitative visual scale of the different patterns of apical root resorption.

METHODS

Eighty-two incisors with apical root resorption from 25 patients had their labial and lingual root surfaces and the longest radicular lengths determined in the sagittal plane and compared. Five orthodontists, at 2 times, classified the images of each incisor according to a visual scale developed by the authors.

RESULTS

There was no significant difference between the labial and lingual surfaces; however, the longest radicular length was significantly greater than the shortest surface length. The visual scale showed intraobserver agreement of 0.615 and interobserver agreements of 0.74 and 0.52 at both times, respectively.

CONCLUSIONS

The difference between the longest and shortest root lengths suggests that radiographic superimposition underestimates the extent of the resorption lesion. The proposed visual scale showed a frequency of agreement above 65% and a coefficient of reproducibility varying from moderate to substantial.

Comparison of cone-beam computed tomography and periapical radiography for detecting simulated apical root resorption

OBJECTIVE

To compare the diagnostic accuracy between cone-beam computed tomography (CBCT) and periapical radiography for detecting simulated external apical root resorption (EARR) in vitro.

MATERIALS AND METHODS

The study sample consisted of 160 single-rooted premolar teeth for simulating EARR of varying degrees according to four setups: no (intact teeth), mild (cavity of 1.0 mm in diameter and depth on root surface), moderate (0.4 mm, 0.8 mm, 1.2 mm, and 1.6 mm root shortening), and severe (2.4 mm, 2.8 mm, 3.2 mm, and 3.6 mm root shortening). Two groups of radiographic images were obtained via CBCT and periapical radiography. The absence or presence and the severity for all resorption lesions were evaluated blindly by two calibrated observers.

RESULTS

With the CBCT method, the rates of correct classification of no, mild, moderate, and severe EARR were 96.3%, 98.8%, 41.3%, and 87.5%, respectively; with the periapical radiography method, the rates were 82.5%, 41.3%, 68.8%, and 92.5%, respectively. Highly significant differences were found between the two imaging methods for detection of mild (P < .001), moderate (P < .001), and all EARR (P < .001). For detection of all EARR, the sensitivity and specificity values were 75.8% and 96.3% for CBCT, compared with 67.5% and 82.5% for periapical radiography.

CONCLUSION

CBCT is a reliable diagnostic tool to detect simulated EARR, whereas periapical radiography underestimates it. However, if a periapical radiograph is already available to the diagnosis of EARR, CBCT should be used with extreme caution to avoid additional radiation exposure.

Film and digital periapical radiographs for the measurement of apical root shortening

Objectives: The aim of this study was to compare the accuracy and agreement of scanned film and digital periapical radiographs for the measurement of apical root shortening. Study design: Twenty-four film and digital [phosphor plate sensor (PPS)] periapical radiographs were taken using the long-cone paralleling technique for six extracted teeth before and after 1mm of apical root trimming. All teeth were mounted using a typodont and the radiographs were recorded using a film holder and polysiloxane occlusal index for each tooth to ensure standardization during the different radiographic exposures. The film radiographs were scanned and the tooth length measurements for the scanned film and digital (PPS) images were calculated using Image-J-Link 1.4 software (http://rebweb.nih.gov/ij/index.html) for the two groups. The accuracy and agreement among the tooth length measurements from each group and the true tooth length measurements were calculated using intra-class correlation (ICC) tests and Bland and Altman plots. Results: A high level of agreement was found between the true tooth length measurements and the scanned film measurements (ICC=0.979, limit of agreement 0.579 to -0.565) and the digital (PPS) radiograph measurements (ICC= 0.979, limit of agreement 0.596 to -0.763). Moreover, a high level of agreement was found between the scanned film and digital (PPS) radiographs for the measurement of tooth length ICC=0.991, limit of agreement 0.411-0.231. Conclusion: Film and digital (PPS) periapical radiographs are accurate methods for measuring apical root shortening with a high level of agreement.

Key words:Root shortening, measurement, periapical radiographs, film, digital.

Apical root resorption due to orthodontic treatment detected by cone beam computed tomography

OBJECTIVE

To determine the frequency of apical root resorption (ARR) due to orthodontic treatment using cone beam computed tomography (CBCT) in a sample of 1256 roots from 30 patients.

MATERIALS AND METHODS

All patients had Class I malocclusion with crowding. Of the 30 patients evaluated, 11 were boys and 19 were girls; their mean age was 13 years (11 to 16 years). Orthodontic treatment followed the nonextraction treatment. CBCT images were obtained before and after orthodontic treatment, and ARR was determined using Axial Guided Navigation of CBCT images.

RESULTS

All patients had ARR. No statistically significant association was found between resorption frequency, gender, and age. ARR was detected using CBCT in 46% of all roots that underwent orthodontic treatment.

CONCLUSIONS

CBCT was effective for detecting in vivo even minimal degrees of ARR due to orthodontic treatment and allowed three-dimensional evaluation of dental roots and visualization of palatine roots of maxillary molars. The highest frequencies and the most significant ARR occurred in incisors and distal roots of first maxillary and mandibular molars.

Physical properties of root cementum: Part 17. Root resorption after the application of 2.5° and 15° of buccal root torque for 4 weeks: a microcomputed tomography study

INTRODUCTION

Root resorption is an undesirable consequence of orthodontic tooth movement. The severity is unpredictable, and, despite extensive research, the etiology remains unknown. Torque has been acknowledged as a risk factor for root resorption. The aims of the study were to evaluate and quantify the extent of root resorption after the application of 2.5° and 15° of buccal root torque for 4 weeks.

METHODS

Fifteen patients requiring bilateral extraction of their maxillary first premolars for orthodontic treatment were recruited to the study. By using a standardized experimental protocol, the right and left premolars were randomly subjected to either 2.5° or 15° of buccal root torque. At the end of the 4-week experimental period, the premolars were extracted. A volumetric analysis of root resorption was performed by using microcomputed tomography and measured with specially designed software.

RESULTS

Overall, the amounts of root resorption were comparable after the application of 2.5° or 15° of buccal root torque (P = 0.59). There was a significant difference between the 2 force levels only at the apical region (P = 0.034). More root resorption occurred in areas of compression than in areas of tension. The variables of age and sex were not statistically significant.

CONCLUSIONS

Root resorption was evident after 4 weeks of buccal root torque application. More root resorption was seen at the apical region than at the middle and cervical regions. Higher magnitudes of torque might cause more root resorption, particularly in the apical region. As shown in previous studies, the etiology of root resorption is multi-factorial and cannot be explained by mechanical factors alone.