Cone beam computed tomography for assessment of root length and marginal bone level during orthodontic treatment

Reliability and agreement of root length measurements during orthodontic treatment in images from different CBCT machines using multiplanar reconstruction

Objectives

To assess inter- and intrarater reliability and agreement for measurements of root lengths using multiplanar reconstruction (MPR) in cone beam computed tomography (CBCT) examinations.Furthermore, to determine whether using MPR from different CBCT machines was a reliable and reproducible method for assessment of root length during orthodontic treatment of adolescents.

Materials and methods

A total of 40 CBCT examinations obtained before, during and after orthodontic treatment of 14 adolescents, with fixed appliances from a multicentre randomised controlled trial, were used. All roots from the incisors to the first molars were measured by two independent raters and in accordance with a protocol preceded by a multi-step calibration. Reliability was assessed by intra class correlation (ICC). Agreement was assessed by measurement error according to the Dahlberg formula and Bland-Altman plot.

Results

The number of repeated measurements varied from 436 to 474 for the different timepoints. Good to excellent inter- and intrarater reliability for different tooth groups and timepoints were shown. Measurement error for inter- and intrarater agreement varied between 0.41 mm and 0.77 mm. The Bland-Altman plot with 95% limits of agreement varied between +1.43 mm and -2.01 mm for different tooth groups and timepoints.

Conclusions

The results of this study indicate that CBCT using MPR from different machines is a reproducible method for measuring root length during different phases of orthodontic treatment. When interpreting root shortening measurements in CBCT using MPR for clinical or research purposes, values below 2 mm should be approached with caution, as they may contain measurement errors.

Effect of low-level laser therapy on en masse retraction in females with bimaxillary dentoalveolar protrusion : A single-center randomized clinical trial

BACKGROUND

Acceleration of tooth movement has gained remarkable attention during the last decade. The aim of this study was to evaluate the effect of low-level laser therapy (LLLT) on en masse retraction of upper anterior teeth in adult women with bimaxillary dentoalveolar protrusion.

MATERIALS AND METHODS

In this two-arm parallel trial, 36 women with bimaxillary dentoalveolar protrusion were randomly divided into two equal groups. Eligibility criteria included class I Angle molar relationship, good general and oral health as well as no systemic disease or syndrome. Four temporary anchorage devices (TADs) were used in the upper and lower arches for anchorage purposes. A 0.019×0.025-inch stainless steel wire with crimped hooks just distal to the maxillary canines was inserted. Nickle titanium (NiTi) closed coil springs (200 g/side) were employed for en masse retraction following extraction of the first premolars. In the laser group (LG), retraction of the upper anterior teeth was done along with the application of LLLT on days 0, 3, 7, and 14 after extraction and then repeated biweekly until the end of retraction. Retraction was completed without LLLT application in the nonlaser group (NLG). Data concerning the rate of retraction as well as first molars and anterior positional changes were gained from digitized models and cone beam computed tomography (CBCT) scans taken just before extraction and at the end of retraction. Treatment-associated pain and root resorption were evaluated using visual analogue scale (VAS) and CBCT scans, respectively.

RESULTS

Four patients dropped out prior to follow-up. The duration of retraction was 10.125 ± 2.876 and 13.643 ± 3.455 months in the LG and NLG, respectively. The LG showed a statistically significant faster rate of en masse retraction (0.833 ± 0.371 mm/month) compared to the NLG (0.526 ± 0.268 mm/month; P ≤ 0.035). The observed root resorption was significantly less in the LG (P ≤ 0.05) with comparable pain scores in both groups.

CONCLUSIONS

Within the constraints of the parameters of the LLLT used in the current study and despite the statistically significant results on the rate of en masse retraction and the associated root resorption, LLLT did not demonstrate a clinically relevant effect that justifies its use to enhance en masse retraction.

NAME OF THE REGISTRY

Clinicaltrials.gov TRIAL REGISTRATION NUMBER: NCT05183451 DATE OF REGISTRATION: January 10, 2022, "Retrospectively registered" URL OF TRIAL REGISTRY RECORD: https://www.

CLINICALTRIALS

gov/study/NCT05183451.

Effects of Occlusal Contact on Maxillary Alveolar Bone Morphology in Patients with and without Anterior Open Bite: A Cross-Sectional Study

Background/Objectives: Anterior open bite (AOB) is characterized by the absence of occlusal contact between the maxillary and mandibular anterior teeth, while the posterior teeth are in contact when occluded. Here, we aimed to clarify the difference in maxillary alveolar bone morphology in adult patients with and without AOB. Methods: This cross-sectional study was conducted on 50 adults aged 18-39 years: 25 patients without AOB (control group; 13 males and 12 females; age: mean ± standard deviation [SD], 22.2 ± 4.5 years) and 25 patients with AOB (9 males and 16 females; age: 24.2 ± 6.4 years). Using cone-beam computed tomography images, the height of the maxillary alveolar bone crest in the anterior and posterior teeth and thickness of the alveolar cortical bone on the labial and palatal sides were measured and compared between the two groups. An independent t-test and Pearson's correlation analysis were used to examine statistical significance (p < 0.05). Results: The AOB group showed a significantly longer (p = 0.016) posterior alveolar crest and thinner cortical bone on the buccal (p < 0.001) and lingual (p = 0.009) sides of the anterior region and the buccal (p = 0.006) sides of the posterior region than the control group did. Moreover, a significant negative correlation (p = 0.046; r = -0.403) was observed between bite force and cortical bone thickness on the buccal side of the posterior region in the AOB group. Conclusions: It is suggested that the absence of occlusal contact in the anterior area influences the alveolar bone morphology of the maxilla.

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

OBJECTIVES

To evaluate the change in tooth root volume using cone-beam computed tomography (CBCT) in a group of patients treated concurrently with clear aligners and an adjunctive photobiomodulation (PBM) device.

MATERIALS AND METHODS

This retrospective cohort pilot study included the records of 32 consecutively treated clear aligner patients (23 female, 9 male) from the private practice of one orthodontist. The PBM group (n = 16) used the device once per day for 5 minutes per arch and was compared with a matched control group (n = 16). A semiautomated segmentation technique was used to obtain tooth volume of anterior teeth from CBCT imaging prior to (T0) and during or immediately following (T1) orthodontic treatment with clear aligners. The change in root volume between time points was assessed.

RESULTS

There was no statistically significant difference between the pre- and posttreatment root volumes of maxillary and mandibular anterior teeth, regardless of which intervention group the patient belonged to (P > .05). There was also no difference in the mean percentage change in root volume between clear aligner patients in this study who were treated with the PBM device compared with a matched control group (P > .05).

CONCLUSIONS

Clear aligner patients in this study who changed their aligners every 3 to 5 days and used adjunctive photobiomodulation therapy did not experience clinically relevant orthodontically induced external root resorption. Due to the small sample size and measurement error in the root segmentation process, the results should be interpreted with caution.

A Quantitative Evaluation of the Effectiveness of the Metal Artifact Reduction Algorithm in Cone Beam Computed Tomographic Images with Stainless Steel Orthodontic Brackets and Arch Wires: An Ex Vivo Study

The presence of high-density and high-atomic number materials results in the generation of artifacts in cone beam computed tomographic (CBCT) images. To minimize artifacts in CBCT images, the metal artifact reduction (MAR) tool was developed. This study aims to quantitatively evaluate the effectiveness of the MAR algorithm in CBCT images of teeth with stainless steel orthodontic brackets with or without arch wires in buccal and lingual positions obtained using the Galileos Sirona CBCT scanner. In this in vitro study, 20 stainless steel brackets were attached to the maxillary dentition from the right second premolar to the left second premolar teeth of a human skull. In the first group, 10 brackets were bonded to the buccal surface, and in the second group, 10 brackets were bonded to the palatal surface of these teeth. CBCT scans were obtained for each group with or without orthodontic stainless steel wires using a Galileos Sirona CBCT scanner with exposure parameters of 85 kVp and 21 mAs. CBCT images were obtained two times with and two times without MAR activation. The DICOM format of the CBCT images was imported to ImageJ software (version 1.54), and the contrast-to-noise ratio (CNR) was calculated and compared for each bracket in 15 and 20 mm distances and 20, 40, and 90 degrees on each side. Statistical analysis was performed using the t test (α = 0.05). CNR values of different distances and different teeth were not significantly different between the two MAR modes (p > 0.05). MAR activation had a significant impact in increasing CNR and reducing artifacts only when brackets were in palatal (p = 0.03). In the other bracket and wire positions, the effect of the MAR algorithm on CNR was not significant (p > 0.05). In conclusion, MAR activation significantly increased CNR, but only when the brackets were in a palatal position. In the other bracket and wire positions, the effect of the MAR algorithm is not significant.

The Validity and Reliability of Automatic Tooth Segmentation Generated Using Artificial Intelligence

This study aimed at evaluating the precision of the segmented tooth model (STM) that was produced by the artificial intelligence (AI) program (CephX®) with an intraoral scan (IOS) and insignia outcomes. Methods. 10 patients with Cl I malocclusion (mild-to-moderate crowding) who underwent nonextraction orthodontic therapy with the Insignia™ system had IOS and CBCT scans taken before treatment. AI was used to produce a total of 280 STMs; each tooth will be measured from three aspects (apexo-occlusal, mesiodistal, and labiolingual) for DICOM and STL formats. Also, root volume measurements for each tooth generated by using the CephX® software and Insignia™ system were compared. The software used for these measurements was the OnDemand3D program used for the multiplanar reconstruction for DICOM format and Geomagic® Control X™ used for STL format. Statistics. An intraclass correlation (ICC) analysis was used to check the agreement between the volume measurement of the segmented teeth generated by using the CephX® and Insignia™ system. Also, it was used to check the agreement between the STL (IOS), STL (CephX®), and DICOM tooth models. In addition, it was used to determine the intraexaminer repeatability by remeasuring five randomly selected individuals two weeks after the initial measurement. After confirmation of the data normality using the Shapiro-Wilk test, the right and left tooth models and the differences between the DICOM, CephX® (STL), and IOS (STL) tooth models were compared using a paired t-test. The STL (IOS), STL (CephX®), and DICOM tooth models were compared utilizing the ANOVA test. p < 0.05 was set as the statistical significance level. Result. Overall data showed good agreement with ICC. The measurements of the various tooth types on the right and left sides did not differ significantly. Also, there was no significant difference between the three groups. Conclusions. The automatic AI approach (CephX®) may be advised in the clinical practice for patients with mild crowding and no teeth restorations due to its speed and effectiveness.

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.

A Correlation Analysis between Arch Width and Molar Inclination Using Cone-Beam Computed Tomography Transverse Measurements: A Cross-Sectional Study

A new era in 3-dimensional analysis has begun with the use of cone-beam computed tomography (CBCT) in orthodontics, which promises to provide a more thorough understanding of the craniofacial skeletal architecture. This study aimed to investigate the correlation between the transverse basal arches discrepancy and dental compensation by utilizing CBCT width analysis. An observational study was conducted to retrospectively review 88 CBCT scans of patients presented to dental clinics from 2014 to 2020 obtained from the Planmeca Romexis x-ray system at three centers. Dental compensation data across normal and narrow maxillae were analyzed and a Pearson correlation was used to find the relationship between molar inclination and width difference. Significant maxillary molar compensation differences were observed between the normal maxilla and narrow maxilla group, where the amount of dental compensation (164.73 ± 10.15) was higher in the narrow maxilla group. A significant negative correlation (r = -0.37) was observed between width difference and maxillary molar inclination. Maxillary molars were tipped buccally to compensate for the reduced maxillary arch width. These findings are important to determine the amount of needed maxillary expansion taking into account the buccal inclination while treating cases.

Morphological analysis of anterior permanent dentition in a Chinese population using cone-beam computed tomography

PURPOSE

Morphological analysis of permanent anterior dentition is essential for achieving an ideal treatment outcome and avoiding unnecessary failure. This study aimed to analyze the morphologies of anterior teeth in the Chinese population in depth.

METHODS

In this retrospective study, 4309 anterior teeth from 401 Chinese patients were investigated using cone-beam computed tomography (CBCT) from 2019-2021. We summarized the morphological characteristics of the anterior teeth in terms of the root length, cementoenamel junction curvature (CEJ-C), root furcation and canal variations.

RESULTS

We found that the root lengths of the maxillary anterior incisors were similar (13.3 mm), while the root lengths of the mandibular central (12.2 mm) and lateral incisors (13.4 mm) varied significantly (p < .0001). Both the maxillary (16.6 mm) and mandibular canines (15.5 mm) were found to have greater root lengths than the corresponding incisors (p < .0001). The CEJ-C was significantly greater around incisors (2.5 mm) than around the canines (2.0 mm) in the maxilla (p < .0001), while the curvature remained similar in mandibular anterior teeth (1.8 mm). Root furcation was observed in mandibular canines and lateral incisors. Moreover, all types of Vertucci's classification in anterior dentitions were observed, while two other new types were found. Among them, the maxilla was only observed to exhibit types I, II, III, and ST II, while the mandible was found to exhibit almost all types. However, Type I still accounts for the majority of dentitions.

CONCLUSIONS

Morphological analysis of permanent anterior dentition revealed diversity in the tooth length, CEJ-C, furcation proportion, and canal variations. In general, mandibular anterior teeth showed a more complex structure than maxillary teeth.

Effects of Low-Level Laser Therapy and Bracket Systems on Root Resorption during Orthodontic Treatment: A Randomized Clinical Trial

This study aimed to assess the outcomes of low-level laser therapy (LLLT) with the conventional bracket (CB) and self-ligating (SL) bracket systems on root resorption (RR) during orthodontic treatment. A total of 32 patients were included in this randomized clinical trial. All the patients were randomly divided into four individual groups (SLL: self-ligating laser, CBL: conventional bracket laser, SLNL: self-ligating non-laser, CBNL: conventional bracket non-laser). RR was measured from the cone-beam computed tomography (CBCT) radiographs which were taken at two stages of the orthodontic treatment: pre-treatment (T1) and after leveling and alignment stage (T2). Wilcoxon rank test for the comparison was conducted to compare the RR at T1 and T2 stages within each group and showed a significant difference (p < 0.05) for various variables. Mann Whitney test compared the RR in laser and non-laser groups irrespective of the bracket systems and exhibited no significant differences except the left lateral incisor. Moreover, CB and SL groups showed no significant difference in RR among any tooth. Kruskal Wallis test was performed to compare the RR among all groups which presented no significant differences. LLLT and bracket systems have no consequences on RR until the leveling and alignment stage of orthodontic treatment.

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.

A quantitative three-dimensional comparative study of alveolar bone changes and apical root resorption between clear aligners and fixed orthodontic appliances

BACKGROUND

This study aimed to evaluate and compare the alveolar bone changes and to investigate the prevalence and severity of orthodontically induced inflammatory root resorption (OIIRR) of maxillary incisors in patients who received treatment with clear aligners (CA) versus conventional fixed appliances (FA), using cone-beam computed tomography (CBCT).

METHODS

One hundred sixty maxillary incisors from 40 patients with similar baseline characteristics based on the American Board of Orthodontics discrepancy index scores were divided into the CA and FA groups. The dentoalveolar quantitative changes were analyzed using pre- (T0) and post-treatment (T1) CBCT. The measured parameters included alveolar bone thickness (ABT), alveolar bone height (ABH), root length (OIIRR), and maxillary incisor inclinations.

RESULTS

Post-treatment, the average palatal and total ABT significantly decreased in central and lateral incisors in the FA group. In contrast, the CA group's average labial ABT of the lateral incisors decreased considerably. Regarding the ABH, both groups showed significant labial and palatal marginal bone resorption. In both groups, root lengths significantly decreased after treatment (p < 0.005). The inter-group comparison revealed that ABT and root length had significantly decreased in the FA group compared to the CA group, while the ABH showed no significant difference between the two groups. The mean absolute reductions of ABT and OIIRR in the CA group were significantly less (- 0.01 ± 0.89 and 0.31 ± 0.42) than those in the FA group (0.20 ± 0.82 and 0.68 ± 0.97), respectively.

CONCLUSIONS

CA and FA treatments appear to cause a significant ABT reduction and a statistically significant increased OIIRR in the maxillary incisor region, with a greater extent expected with FA treatment. However, the increased OIIRR values in the majority of both groups' cases were not clinically significant. Both treatment modalities resulted in a significant ABH reduction, with the highest found in the labial side of lateral incisors in the CA group.

Assessment of thin bony structures using cone-beam computed tomography

OBJECTIVES

To investigate the validity and reliability of marginal bone level measurements on cone-beam computed tomography (CBCT) images of thin bony structures using various reconstruction techniques, two image resolutions, and two viewing modes.

MATERIALS AND METHODS

CBCT and histologic measurements of the buccal and lingual aspects of 16 anterior mandibular teeth from 6 human specimens were compared. Multiplanar (MPR) and three-dimensional (3D) reconstructions, standard and high resolutions, and gray scale and inverted gray scale viewing modes were assessed.

RESULTS

Validity of radiologic and histologic comparisons were highest using the standard protocol, MPR, and the inverted gray scale viewing mode (mean difference = 0.02 mm) and lowest using a high-resolution protocol and 3D-rendered images (mean difference = 1.10 mm). Mean differences were significant (P < .05) at the lingual surfaces for both reconstructions, viewing modes (MPR windows), and resolutions.

CONCLUSIONS

Varying the reconstruction technique and viewing mode does not improve the observer's ability to visualize thin bony structures in the anterior mandibular region. The use of 3D-reconstructed images should be avoided when thin cortical borders are suspected. The small difference when using a high-resolution protocol is unjustified due to the higher radiation dose required. Previous studies have focused on technical parameters; the present study explores the next link in the imaging chain.

Three-dimensional analysis of root changes after orthodontic treatment for patients at different stages of root development

INTRODUCTION

We investigated changes in the roots of maxillary incisors at different stages of root development after fixed-appliance treatment using cone-beam computed tomography.

METHODS

Data from 52 subjects receiving fixed-appliance treatment were collected retrospectively. The subjects were divided into 3 groups: mixed dentition group (aged 7-10 years; root development stage: Nolla eighth-10th; n = 16), early permanent dentition group (aged 12-18 years; root development stage: Nolla 10th; n = 20), and adult group (aged 18-35 years; root development stage: Nolla 10th; n = 16). Changes in root lengths and volume of the maxillary central incisors were measured using pretreatment and posttreatment cone-beam computed tomography.

RESULTS

The root lengths and volumes of maxillary central incisors in the mixed dentition group significantly increased after orthodontic treatment (P >0.05). No significant differences were found when comparing the final root length and volume of the mixed dentition group with the pretreatment maxillary incisor values of the early permanent dentition group (P >0.05). The early permanent dentition group showed a significant decrease in root length (P <0.05), and both the root length and volume of the adult group significantly decreased after treatment (P <0.05). The differences in root length and volume reduction between the 2 groups were not significant (P >0.05).

CONCLUSIONS

Orthodontic treatment had no significant negative impact on the continued root development of incomplete roots with two-thirds root formation. Both the early permanent dentition and adult groups exhibited root resorption after orthodontic treatment. It seemed age was not a factor that resulted in significant root resorption during routine orthodontic leveling and alignment treatment once the roots were fully developed.

Effect of cigarette smoking on alveolar bone thickness and density in patients undergoing leveling and alignment of crowded lower anterior teeth: a controlled clinical trial

OBJECTIVE

To evaluate the effect of cigarette smoking on the alveolar bone thickness and density in patients undergoing leveling and alignment of crowded lower anterior teeth.

METHODS

This controlled clinical trial involved 17 smokers and 17 nonsmokers with mild to moderate crowding of the anterior mandibular teeth. Two cone-beam computed tomography images of the mandible were taken before and after treatment. The length of each tooth root was calculated in each T0 image, and the root was divided into three equal regions. Three lines were drawn parallel to the line of the cementoenamel junction at these three regions of the root, and the previously drawn lines were used to measure bone thickness and bone density.

RESULTS

The mean changes in cortical bone thickness and bone density were significantly smaller in smokers than nonsmokers. Cortical bone thickness and bone density were significantly lower after than before treatment in both smokers and nonsmokers.

CONCLUSION

In addition to all of its known dangers, cigarette smoking may also harm the alveolar bone by decreasing the bone thickness and density during orthodontic treatment in heavy smokers.

Cone‐Beam Computed Tomography Assessment of Maxillary Anterior Alveolar Bone Remodeling in Extraction and Non‐Extraction Orthodontic Cases Using Stable Extra‐Alveolar Reference

OBJECTIVE

To explore alveolar cortical positional change in response to tooth movement in extraction and non-extraction orthodontic cases, using cone-beam computed tomography (CBCT) and stable extra-alveolar references.

MATERIALS AND METHODS

The pre-treatment (T1) and post-treatment (T2) CBCT scans of 25 extraction (EXT) and matched 25 non-extraction (Non-EXT) orthodontic cases were imported into Dolphin Imaging 3D, and oriented uniformly. Sagittal and axial CBCT cross-sections were traced using customized software-generated guides. The displacement of teeth and alveolar bone cortices were automatically measured using the palatal plane (PP) and the line perpendicular to PP and passing Sella as reference. Intra- and inter-group differences between T1 and T2 were analysed. Subjects were also superimposed three-dimensionally using Geomagic Control X for qualitative analysis of cortical remodelling.

RESULTS

The EXT group showed incisor retraction, while the Non-EXT group exhibited statistically significant incisor anterior tipping (P < .05). In EXT, both the labial and palatal cortices are resorbed. Non-EXT showed labial cortex anterior modelling, and statistically significant palatal cortex resorption (P < .05). In both groups, statistically significant decrease in total and palatal alveolar widths, increase in labial widths, and palatal dehiscence were observed. Comparatively, EXT showed significantly more incisal total and palatal width decrease and palatal vertical bone loss.

CONCLUSION

Labial cortical remodelling was shown to follow anterior tooth movement, but the palatal cortical response to incisor retraction and labial cortical remodelling in general remained inconclusive. Narrowing of the alveolar housing and palatal dehiscence were observed regardless of extraction following orthodontic treatment.

Ideal transverse position of mandibular first molars based on CBCT-derived alveolar bone coverage

BACKGROUND

In orthodontic treatment, transverse arch width often needs to be adjusted to correct anomalies such as posterior crossbite. Ideal transverse arch width at the first molars enabling long-term stability and periodontal health, however, requires sufficient posttreatment bony coverage buccally and orally of the tooth roots. Thus, the aim of this retrospective study was to determine the physiological alveolar bone thickness at the buccal and oral roots of the first mandibular molars in the general population using human CBCT scans assessing local and gender-specific differences.

METHODS

CBCTs of 124 random 11- to 55-year old patients (46 female, 78 male) were analysed retrospectively. Alveolar bone thickness was measured digitally at mesial and distal tooth roots of the first mandibular molars buccally and orally at different vertical positions (4 and 8mm apically of the cement-enamel-junction CEJ). For each patient, the mean of corresponding measurements from left and right molars was used for analysis.

RESULTS

All measurements were reliable, as proven by interrater- and interrater-reliability-testing. On average, bone thickness increased from the mesial to the distal tooth root, as well as in apical and oral direction. These local differences in alveolar bone thickness were all highly significant at p < 0.0001. Women showed thicker bone buccally at the distal tooth root at 8mm apically of the CEJ, as well as orally at both mesial and distal tooth roots 4mm apically of the CEJ.

CONCLUSIONS

The results of this study suggest that especially in buccal, mesial and gingival direction alveolar bone around mandibular first molars becomes thinner and hence the scope for orthodontic tooth movements is limited. Our results should aid assessing ideal transverse molar position based on alveolar bone coverage, although variations due to age may occur.

Morphometric Analysis Comparing Human Mandibular Deciduous Molars using Cone Beam Computed Tomography

Background

The presence of variations in crown and root measurements in deciduous teeth usually leads to complications during and after treatment. Hence, in order to improve the success rate in pediatric treatment, there must be proper knowledge of dental morphological and morphometric characteristics of deciduous teeth among different populations.

Objective

The aim of the present study was to assess length of the crowns, length of the roots, roots to crown (R/C) ratio, and distance between the floor of pulp chamber to furcation using cone beam computed tomography (CBCT).

Materials and Methods

Extracted deciduous molar teeth were collected and divided into: group I: Deciduous mandibular first molars (lower D) (n = 16) and Group II: Deciduous mandibular second molars (lower E) (n = 21). The length of the crowns, length of the roots, R/C ratio and distance between the floor of pulp chamber and furcation were measured using CBCT. Data were statistically analyzed.

Results

Lower D showed smaller crown length with a mean of 4.87 mm, longer mesial root length with a mean of 9.68 mm and greater R/C ratio with a mean of 2 mm when compared to lower E. As for the distal root length and the distance between the floor of the pulp chamber and the furcation area, both molars closely resembled each other. There was a statistical significant difference between both molars regarding mesial root length, crown length, and R/C ratio.

Conclusion

The current study concluded that dental morphological characteristics are important in research as they provide valuable information about diversities within a population.

Open vs closed surgical exposure of palatally displaced canines: a comparison of clinical and patient-reported outcomes-a multicentre, randomized controlled trial

OBJECTIVES

To compare treatment time, patients' perceptions during orthodontic treatment, dental fear and side effects, between open and closed surgical exposures in patients with palatally displaced canines (PDCs).

TRIAL DESIGN

Multicentre, randomized controlled trial, with random 1:1 allocation of two parallel groups.

MATERIALS AND METHODS

One hundred and twenty patients from three different orthodontic centres were randomized into one of the two intervention arms, open or closed surgical exposure. Both techniques had mucoperiosteal flaps raised and bone removed above the PDCs. In open exposure, tissue was removed above the canine, and glass ionomer - reaching above soft tissue - was built on the crown. The canine was then left to erupt spontaneously, prior to orthodontic alignment. At closed exposure, a chain was bonded to the canine and orthodontic traction was applied under the mucosa until eruption. Orthodontic alignment of the canines was undertaken after eruption into the oral cavity, with fixed appliances in both groups. All participants were treated according to intention to treat (ITT).

BLINDING

Due to the nature of this trial, only outcome assessors could be blinded to the intervention group.

RESULTS

One hundred and seventeen patients completed the trial. All PDCs were successfully aligned. Total treatment time was equal in the two techniques, mean difference -0.1 months (95% CI -3.2 to 2.9, P = 0.93). The closed group experienced more pain and discomfort during the active orthodontic traction. Dental fear, root resorption and periodontal status did not show any clinically significant differences between the groups.

GENERALIZABILITY

Results of this randomized controlled trial (RCT) can be generalized only to a similar population aged 9-16 years, if exclusion criteria are met.

CONCLUSION

The closed exposure group experienced more pain and discomfort mostly during active orthodontic traction. All other studied outcomes were similar between the two exposure groups.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT02186548 and Researchweb.org, ID: 127201.

Impact of piezocision-assisted orthodontics on root resorption and alveolar bone: a prospective observational study

OBJECTIVES

To assess the impact of orthodontic treatment combined with piezocision (OT-PC) on root structure and alveolar bone.

MATERIALS AND METHODS

Twelve adults were treated with OT-PC. Pre- and post-treatment CBCT examinations evaluated apical root resorption (ARR) and alveolar bone height and thickness changes. Pre- and post-treatment differences were compared using one-sample t test and Wilcoxon signed-rank test.

RESULTS

ARRs were generalized and significantly more severe in both anterior sextants compared with posterior sextants. Bone thickness decreased significantly in the maxilla at mid-root and apex areas. The majority of mandibular alveolar bone dehiscences occurred on the buccal aspect at the mid-root level, especially where thickness was less than 0.3 mm. Overall bone height decreased twice as much on the buccal aspect (1.43 mm, P < 0.001) compared with the lingual aspect (0.67 mm, P = 0.001), most significantly in the lower incisors, where the average median loss was 2.10 mm (P = 0.003).

CONCLUSION

OT-PC causes minor negative effects on both alveolar bone and root resorption.

CLINICAL RELEVANCE

Orthodontic treatment combined with piezocision causes minor negative effects on periodontal support. Nevertheless, mild bone height loss on the buccal aspect of the mandibular teeth and root resorption in both anterior sextants have been detected with this new treatment.

Three-dimensional assessment of accelerating orthodontic tooth movement-micro-osteoperforations vs piezocision: A randomized, parallel-group and split-mouth controlled clinical trial

OBJECTIVE

To compare the effects of micro-osteoperforations (MOPs) vs piezocision (Piezo) in accelerating orthodontic tooth movement in adults.

SETTING AND SAMPLE POPULATION

In this randomized, single-blinded, parallel-group, split-mouth clinical trial, 24 patients aged 15-40 years were recruited.

SUBJECTS AND METHODS

Patients were randomly allocated into two groups: MOPs and Piezo groups. One side of the maxilla was allocated randomly for treatment with one of these techniques, and the other side was treated conventionally to act as a split-mouth control. The rate of canine retraction was evaluated up to 3 months by three-dimensional digital models using a conventional labial appliance. Root resorption and bone height were evaluated using cone beam computed tomography.

RESULTS

The MOPs and Piezo groups showed a significantly higher rate of tooth movement after 3 months on the experimental sides than the control sides. However, the net movements in the MOPs and Piezo groups did not reveal a higher rate of tooth movement. Similarly, the overall net movement was -0.32 ± 1.14 and -0.55 ± 0.89 mm for MOPs and Piezo, respectively (P = .606). Regarding root resorption, the overall changes in intra- or intergroup comparisons were insignificant. Decreased canine palatal bone height was reported on the experimental side of the Piezo group (P = .015) after 3 months, but the overall changes were insignificant.

CONCLUSIONS

The effect of MOPs and Piezo techniques in accelerating the orthodontic canine retraction was comparable to each other, and to the conventional methods. Neither technique caused root resorption or increased vertical bone loss.

Comparative Reliability Assessment of Tooth Volume Measurement with Different Three-Dimensional Imaging Software

Objective. To evaluate the in vivo tooth volume through VRMesh and 3Matic programs and to compare the measurements to the physical volume. So, the aim of the study was to ensure the reliability and sensitivity of the three-dimensional software (VRMesh and 3Matic) in measuring tooth volume. Material and Methods. The volume of 26 extracted upper first premolars from orthodontic patients who had CBCT before orthodontic treatment were measured. Two different commercial programs, which were VRMesh and 3Matic, were used to calculate the volume of the segmented upper first premolar from CBCT. The in vivo tooth volume was compared to the physical tooth volume to examine the accuracy of the two software in measuring the tooth volume. Results. The difference between the mean of the in vivo and in vitro tooth volume measurements was too small, making it clinically nonsignificant. ANOVA test was used as a statistical tool, and no statistically significant difference was noticed among the measurements. The values were normally distributed when tested for normality by Kolmogorov-Smirnov and Shapiro-Wilk test. $\mathit{P}$ value less than or equal to 0.05 ( $\mathit{P}\le 0.05$ ) was considered statistically significant. Conclusion. The assessment of the in vivo tooth volume measurement with different three-dimensional imaging software (VRMesh and 3Matic) programs in comparison with the tooth physical volume is reliable. The use of a mouse pen during the refining stage of the segmentation may have increased the accuracy of the procedure. The determined in vivo tooth volumes are dependable and can be applied in orthodontic diagnosis and treatment planning.

Volumetric measurements of mandibular incisor root resorption following Forsus FRD EZ2 and Bionator appliance treatment using cone-beam computed tomography: A preliminary study

Objectives:

Root resorption is one of the frequently encountered problems in orthodontic treatments. The effects of functional appliances on root resorption have not been clearly demonstrated. The aim of this study was to compare volumetric root resorption of mandibular incisors after Bionator and Forsus appliance treatment using cone-beam computed tomography (CBCT).

Materials and Methods:

The study sample (n = 30) was selected from Class II div. 1 mandibular retrognathia patients treated with the Bionator and Forsus appliances. The first CBCT scans were taken before Bionator use and after 6 months. In the Forsus group, the first CBCT scans were taken before Forsus appliance use and after an overcorrected Class I relationship was obtained. The mean treatment time with the Forsus appliance was 5 ± 1.2 months. Mimics software was used for segmentation and volumetric measurements of mandibular incisor teeth root resorption.

Results:

In the Bionator group, statistically significant root volume loss was not found. In the Forsus group, the differences between before and after the treatment were not statistically significant for teeth 41, 31, and 32 (P > 0.05), whereas the difference was statistically significant for the lower right second incisor (P < 0.002). The percentage of volume loss (%) and root volume loss (mm3) was not statistically significant between groups.

Conclusions:

Following functional treatment with the Bionator and Forsus, statistically significant difference was not found between groups for mandibular incisor root resorption.

Evaluation of Root Resorption, Tooth Inclination and Changes in Supporting Bone in Class II Malocclusion Patients Treated with Forsus Appliance

OBJECTIVE

The aim of our study was to evaluate apical root resorption and changes in tooth inclinations, marginal bone height, and labio-lingual bone thickness at the mid-root and apical level in mandibular anterior teeth during the Forsus treatment using cone beam computed tomography (CBCT).

METHODS

CBCT scans of 16 subjects (8 males and 8 females) with Class II malocclusion (age group: 13-29 years) taken before and 6 months after the Forsus treatment were evaluated for apical root resorption, tooth inclination, marginal bone height, and thickness of bone at the mid-root and apical level in mandibular anterior teeth.

RESULTS

There was statistically significant root resorption of central incisors (0.39 mm) and canines (0.66 mm); a decrease in the angle of inclination for all teeth; an increase in the marginal bone measurement in labial (1.31 mm) and decrease in lingual (0.93 mm) aspect at the canine region; and an increase in bone width by 0.87 mm and 0.75 mm in central and lateral incisor regions, respectively, at the mid-root level lingually. At the apex level in the canine region, bone width increased by 1.4 mm labially, while it decreased by 2.18 mm lingually; it increased significantly for incisors in the lingual region.

CONCLUSION

The Forsus appliance therapy causes clinically insignificant root resorption and bone changes, and clinically significant proclination of mandibular anterior teeth. The findings of the present study aid clinicians in proper case selection and reinforce the prevention of incisor proclination while using the Forsus therapy to achieve better treatment results and stability.

Effect of orthodontic treatment on alveolar bone thickness in adults: a systematic review

Objectives:

This review aimed at evaluating changes in alveolar bone thickness after completion of orthodontic treatment.

Methods:

Only prospective clinical studies that reported bone thickness in adult patients undergoing non-surgical orthodontic treatment were considered eligible. MEDLINE, EMBASE and LILACS databases were searched for articles published up to July 2018.

Results:

A total of 12 studies met the selected criteria. Most of the studies showed that orthodontic treatment produces a reduction in bone thickness of incisors, mainly at the palatal side.

Conclusion:

On patients undergoing different orthodontic treatment techniques, there was a significant bone thickness reduction, mainly on the palatal side.

Clinical relevance:

These findings are relevant and have to be considered in diagnosis and planning of tooth movement, in order to prevent the occurrence of dehiscence and fenestration in alveolar bone.

Outcome of periodontal–orthodontic treatment in subjects with periodontal disease. Part II: a CBCT study of alveolar bone level changes

Aim

To examine alveolar bone level (ABL) changes before (T1) and after (T2) orthodontic treatment (OT) in subjects with periodontal disease.

Methods

The study included 50 subjects with periodontal disease. All patients received subgingival debridement following baseline examination. Control group patients received final periodontal treatment before the start of OT. For the test group patients final periodontal treatment was performed simultaneous to OT. OT was performed with a straight-wire appliance. Micro-implants or temporary crowns on implants were used for posterior anchorage when needed. ABL measurements of 3821 tooth surfaces were performed on cone beam computed tomography images.

Results

No difference was observed between mean ABL at T1 and T2. ABL remained unchanged on 69 per cent of surfaces. A mean of 15.6 (SD 7.4) per cent of surfaces experienced ABL gain, and a mean of 15.1 (SD 7.5) per cent was found with ABL loss. Small significant median ABL difference was observed on mesial and distal surfaces (P < 0.001). A significant difference was found between median ABL changes on mesial/distal in comparison to buccal/lingual surfaces (P < 0.01). Significantly more buccal (17.9 %) and lingual (18.5 %) surfaces experienced ABL loss when compared with mesial (11.3 %) and distal (12.0 %) surfaces (P < 0.001). Significant difference was found in the median ABL change of intruded (0.5 (IQR 0.94) mm) and non-intruded (−0.4 (IQR 1.07) mm) maxillary incisors (P = 0.04). Significant median ABL gain was found on the lingual surface of maxillary incisors, which were retroclined more than 8.6 degree and intruded more than 1.6 mm.

Conclusions

ABL changes after periodontal–orthodontic treatment in patients with periodontal disease were small. ABL gain was more observed on mesial and distal surfaces and ABL loss on buccal and lingual surfaces. Larger orthodontic movements of maxillary incisors influenced ABL gain.

Oro-dental characteristics in patients with hypermobile Ehlers-Danlos Syndrome compared to a healthy control group

BACKGROUND

Ehlers-Danlos syndrome (EDS) is a hereditary disorder that affects the connective tissue and collagen structures in the body characterised by joint hypermobility, skin hyperextensibility and tissue fragility.

OBJECTIVE

The aim of the study was to investigate the oro-dental characteristics including measurements of tooth size of 26 patients with hypermobile EDS (hEDS), differentiated by a genetic test, compared to 39 healthy controls.

METHODS

Interview, clinical and radiological examination on panoramic radiograph and cone-beam computed tomographic (CBCT) scan were performed. Statistical analyses included Fisher's exact test, paired t test and multiple logistic and linear models adjusted for age and gender.

RESULTS

The experience of xerostomia (P = 0.039), local anaesthetic insufficiency (P < 0.001) and tooth extraction complications (P < 0.003) were significantly higher in hEDS compared to controls. The debris index was significantly higher in hEDS (P < 0.001), and the distance between the cement-enamel junction (CEJ) and the bone level on the upper left first incisor and molar and the lower right first molar was significantly larger in hEDS compared to controls (P = 0.021, P = 0.024, P = 0.021, respectively). The crown heights of the upper and lower first incisors were significantly smaller (P = 0.001, P = 0.003, P = 0.002, P < 0.001, respectively) in hEDS compared to controls. When adjusting for debris index, only the distance between CEJ and the marginal bone level on the upper left and lower right molar was associated with hEDS.

CONCLUSION

The results indicate that xerostomia, resistance to local anaesthesia, tooth extraction complications, poor oral hygiene, larger distance between CEJ and marginal bone level and small crown heights can be found in patients with hEDS.

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.

Evaluation of orthodontically induced external root resorption following orthodontic treatment using cone beam computed tomography (CBCT): a systematic review and meta-analysis

Background

Orthodontically induced external root resorption (OIRR) is a pathologic consequence of orthodontic tooth movement. However, the limitations of two-dimensional radiography suggest that cone beam computed tomography (CBCT) with its three-dimensional capabilities might be more suitable to assess OIRR.

Objective

The aim of this study was to assess in an evidence-based manner data on linear or volumetric OIRR measurements of permanent teeth by means of CBCT, during and/or after the end of orthodontic treatment.

Search methods

Unrestricted electronic and hand searches were performed up to January 2017 in 15 databases.

Selection criteria methods

Randomized clinical trials, prospective, and retrospective non-randomized studies assessing OIRR during and/or after orthodontic treatment using CBCT in human patients were included.

Data collection and analysis

After duplicate study selection, data extraction, and risk-of-bias assessment according to the Cochrane guidelines, random-effects meta-analyses, followed by subgroup, meta-regression, and sensitivity analyses were also performed in order to evaluate factors that affect OIRR.

Results

A total of 33 studies (30 datasets) were included in the qualitative analysis while data from 27 of them were included in the quantitative analysis. Direct comparisons from randomized trials found little to no influence of appliance-related factors on OIRR. Explorative analyses including non-randomized studies found a pooled OIRR of 0.79 mm based on all included studies and 0.86 mm when OIRR was assessed at the end of orthodontic treatment. Statistically significant differences in OIRR were found according to tooth type or jaw, inclusion of extractions, treatment duration, and diagnostic accuracy of the CBCT.

Conclusions

Based on the results of this study, CBCT seems to be a reliable tool to examine OIRR during or at the end of orthodontic treatment. Although the average OIRR measured with CBCT seems to lack clinical relevance, there are certain factors that may affect OIRR following orthodontic treatment. Nevertheless, due to data heterogeneity and low quality of the included studies, the corresponding results should be interpreted with some caution.

Registration

PROSPERO (CRD42016030131).

Measurability and reliability of assessments of root length and marginal bone level in cone beam CT and intraoral radiography: a study of adolescents

OBJECTIVES

To evaluate measurability and reliability of measurements of root length and marginal bone level in CBCT, periapical (PA) and bitewing (BW) radiographs.

METHODS

CBCT of both jaws, PA of maxillary incisors and posterior BW radiographs of 10 adolescents (mean age 13.4) were selected. The radiographs comprised part of the baseline examinations of a trial of orthodontic treatment. Six raters assessed measurability and measured root length and marginal bone level. Three raters repeated their assessments. Measurability was expressed as frequency of interpretable sites and reliability as intraclass correlation coefficient (ICC).

RESULTS

Measurability was 100 % in CBCT and 95 % in PA of maxillary incisors for root length measurements. For marginal bone level, measurability was 100 % in CBCT, 76 % in PA and 86 % in posterior BW. Mean ICC for interrater reliability for root length measurements in CBCT was 0.88 (range 0.27-0.96 among different teeth) and 0.69 in PA of maxillary incisors. For marginal bone level measurements, mean ICC was 0.4 in CBCT, 0.38 in PA of maxillary incisors and 0.4 in posterior BW. Intrarater reliability varied among methods, root length or marginal bone level and among raters, except for root length measurements in CBCT, which presented high reliability (above 0.8) for all raters.

CONCLUSIONS

As measurability and reliability were high for root length measurements in CBCT, this may be the method of choice for scientific analyses in orthodontics. For clinical praxis, we recommend PA following the "as low as diagnostically acceptable" principle, as clinical decisions seem to be influenced only when severe root resorption occurs.

Evaluation of root canal morphology of mandibular premolars in a Saudi population using cone beam computed tomography: A retrospective study

Objective

To investigate the root canal morphology of mandibular first and second premolars using Cone-Beam Computed Tomography (CBCT) in a Saudi population.

Methods

CBCT images of 707 patients, number of roots and canal configuration were identified and categorized according to Vertucci classification. Bilateral symmetry and association between gender and number of roots, as well as gender and root canal configuration were investigated.

Results

Majority of the patients had one root and type I root canal configuration in mandibular first (96.4%) and second premolar (95.6%). All types of canal configurations were observed except Type VII for the mandibular first premolar, and Types VI and VII for the mandibular second premolar. High degree of bilateral symmetry was seen in both mandibular first and second premolars in terms of the number of roots and canal configuration; 93.8% and 97.8%, respectively. There was an association between gender and number of roots (P = 0.04) and gender and root canal configuration in mandibular first premolar (P = 0.030).

Conclusions

Single-root with type I canal configuration was the most prevalent of mandibular premolars in the Saudi population. However, incidence of more than one root with different canal configurations was detected.

Anterior teeth root inclination prediction derived from digital models: A comparative study of plaster study casts and CBCT images

BACKGROUND

To assess the accuracy of digital models generated using commercially available software to predict anterior teeth root inclination characteristics and compare the results to relevant data obtained from CBCT images.

MATERIAL AND METHODS

Following sample size calculation and after application of inclusion and exclusion criteria, pre-treatment maxillary and mandibular plaster models and the corresponding CBCT scans of 31 patients attending a private orthodontic clinic were selected. The subjects were 10 males and 21 females with age range 12 to 40 years. Plaster models were scanned using the high resolution mode of an Ortho Insight 3D scanner and CBCT scans were taken using a Kodak 9500 Cone Beam 3D System machine. The teeth on the digital scans were segmented and virtual roots were predicted and constructed by the Ortho Insight 3D software. The long axes of the predicted roots and the actual roots, as segmented from the CBCT images, were computed using best-fit lines. The inter-axis angle was used to assess error in root inclination prediction by the software. Mann-Whitney and Kruskal-Wallis tests were used. Intra-examiner error was evaluated using the Bland-Altman method.

RESULTS

The maximum disparity in angle between images derived from digital models and CBCT data was almost 40 degrees (upper left canine). The upper and lower canines produced the worst results, followed by the lower lateral incisors. The upper central incisors showed the best results, although the maximum angle of difference exceeded 20 degrees (with the median around 8 degrees).

CONCLUSIONS

Root morphology imaging prediction is not a primary function of this software and this study confirmed its limitation as a sole tool in routine clinical applications. At present these predictions cannot be considered accurate or reliable unless correlated clinically with a radiographic image. Key words:Digital models, CBCT, tooth root inclination prediction software.

Apical root resorption during orthodontic treatment with clear aligners: A retrospective study using cone-beam computed tomography

INTRODUCTION

We aimed to investigate the incidence and severity of orthodontically induced inflammatory root resorption (OIIRR) on maxillary incisors with clear aligner therapy using cone-beam computed tomography and to identify possible risk factors.

METHODS

The root lengths of maxillary incisors were measured on orthogonal images from pretreatment and posttreatment cone-beam computed tomography examinations of 160 patients who received comprehensive orthodontic treatment with clear aligners.

RESULTS

Mean absolute reductions in root length varied between 0.47 ± 0.61 mm and 0.55 ± 0.70 mm and were not significantly different between maxillary central and lateral incisors. The prevalence of severe OIIRR, defined as both maxillary central incisors experiencing greater than a 25% reduction in root length, was found to be 1.25%. Potential risk factors included sex, malocclusion, crowding, and posttreatment approximation of apices to the cortical plates. Race, interproximal reduction, previous trauma to the teeth, elastics, age, treatment duration, and pretreatment approximation of apices to the cortical plates did not significantly affect the amount of OIIRR.

CONCLUSIONS

Comprehensive treatment with clear aligners resulted in minimal root resorption. Sex, malocclusion, crowding, and posttreatment approximation to the cortical plates significantly affected the percentage of change in root length. Posttreatment approximation of root apices to the palatal cortical plate showed the strongest association for increased OIIRR.

Cone Beam Computed Tomography in Orthodontics

Orthodontists treat malocclusions by applying three-dimensional forces. For years, the diagnosis of this three-dimensional condition and the related treatment plan has been based on two-dimensional imaging. Lateral and anteroposterior cephalometric, panoramic, and periapical radiographs are some of the two-dimensional radiographs routinely used in orthodontics. Despite being highly beneficial in evaluating skeletal and dental relations, these radiographs fail to provide sufficient two-dimensional information in certain cases. The purpose of this compilation is to review the use of cone-beam computed tomography in orthodontics.

3D reconstruction images of cone beam computed tomography applied to maxillofacial fractures: A case study and mini review

Maxillofacial injuries can be complex and are clinically important due to their functional and cosmetic significance. Maltreated and missed fractures might cause deformity of the face; thus, accurate evaluation of the fracture provided by X-ray images is critical. In this study, we explore the application of cone-beam computed tomography (CBCT) for diagnosis of severe maxillofacial traumas. A patient with a complex fracture that affects the maxilla, mandible, wall of the maxillary sinus, zygoma, zygomatic arch and nasal bone was diagnosed using 3D reconstruction of CBCT images. This diagnostic approach provides detailed information obtained by static images and a systematic model with unique advantages for the following pre-surgical evaluation, surgical treatment and prognostic assessment of complex maxillofacial fractures.

Buccal Plate Preservation with Immediate Implant Placement and Provisionalization: 5-Year Follow-Up Outcomes

Purpose

Despite socket preservation and/or immediate implant placement, resorption of the buccal plate after dental extraction continues to pose esthetic challenges to clinicians. Buccal plate preservation (BPP) is a technique that has been recently proposed with an aim to reduce the incidence of such resorption. This study was conducted to assess the long-term efficacy of BPP in maintaining the thickness of the buccal cortical plate after immediate implant insertion and provisionalization.

Materials and Methods

Ten consecutive patients were included in this study. Each patient underwent extraction of a non-restorable tooth, BPPPBPP, single immediate implant placement and immediate provisionalization. Cone beam CT scans were taken 3 months after surgery (T1) and 5 years after surgery (T2) to evaluate the effectiveness and longevity of the BPPPBPP technique in maintaining the augmented bone width. Two distinct measurements were taken for bone evaluation: (a) R1: 1 mm apical to the implant platform and (b) R2: 5 mm apical to the implant platform. The long axis of the implant was used as a fixed reference. Statistical test analysis was conducted using the SPSS software. Student's t test was used to assess statistical significance, and a p value of < 0.05 was considered significant.

Results

There were six females and four males in the study. The mean age of the sample was 37.6 years (range 23-64 years). At T1, the mean bone thickness of the buccal plate was found to be 2.36 mm at R1 (range: 1.9-3.1), and 2.23 at R2 (range: 1.9-3). At the T2 interval, the mean thickness of the plate was 2.28 mm at R1 (range: 1.7-3) and 2.18 at R2 (range: 1.9-3). The differences in these mean values were not statistically significant.

Conclusions

BPPPBPP is an effective means for augmentation and maintenance of the buccal cortical plate around an immediately placed and provisionalized dental implant. It is a viable alternative to socket preservation with the added benefit that it allows for immediate implant placement.

Evaluation of maxillary central incisors on the noncleft and cleft sides in patients with unilateral cleft lip and palate-Part 1: Relationship between root length and orthodontic tooth movement

OBJECTIVES

To measure the root lengths of maxillary central incisors (U1) and evaluate the relationship among U1 root length, tooth movement, and type of treatment appliance in patients with unilateral cleft lip and palate over a long-term follow-up period.

MATERIALS AND METHODS

Occlusal radiographs of 30 patients with unilateral cleft lip and palate, acquired less than 6 months before secondary alveolar bone grafting (SBG, T1) and after edgewise treatment (T2), were measured for U1 root length (R1 and R2, root lengths at T1 and T2, respectively). Frontal and lateral cephalometric radiographs acquired at eruption of U1 (T0), T1, and T2 were evaluated to determine the inclination and position of U1.

RESULTS

The average values of R1 and R2 on the cleft side were significantly lower than those on the noncleft side. Frontal cephalometric analysis revealed that the horizontal distance of the root apex from the median vertical line at T0 on the cleft side was significantly smaller than that on the noncleft side and was correlated with short U1 root length on the cleft side. On the other hand, R1 in patients treated with maxillary protraction appliances between T0 and T1 was significantly shorter than that in patients without maxillary protraction appliances. However, none of the changes in cephalometric measurements were correlated with root length.

CONCLUSIONS

In patients with unilateral cleft lip and palate, the short root length of cleft-adjacent central incisors might be associated with the horizontal position of the root apex. In addition, orthodontic treatment with a maxillary protraction appliance before secondary alveolar bone grafting might be associated with short U1 root length.

Three-dimensional characterization of root morphology for maxillary incisors

The aim of this study was to test the reproducibility of three-dimensional (3D) surface models of maxillary incisors and to propose a characterization of root morphology. The sample was comprised of pre-treatment cone-beam computed tomography (CBCT) images of fifty-five patients. The CBCTs were used to construct 3D surface models of the maxillary incisors. The reproducibility of surface models was tested by repeated construction of them by two observers. A 3D surface model that corresponded to the average of all lateral and all central incisors was generated. 3D surface distances and vector differences were calculated for each individual tooth and the average of the teeth considered. The corresponding points on the 3D surface mesh for each subgroup were compared statistically to those of the neutral subgroup using shape analysis MANCOVA and Hotelling's t-statistic (p < 0.05). Repeated construction of surface models demonstrated adequate inter-rater reproducibility. The distribution of 3D models into root morphology subgroups was: blunt (11% and 26% of the central and lateral incisors, respectively), conical (15% of the central incisors), long (27% and 20% of the central and lateral incisors, respectively), and short (15% and 4% of the central and lateral incisors, respectively). Compared to the neutral average, statistically significant differences in root morphology were found for blunt, long, conical, and short central incisors and for blunt, long, and short lateral incisors. We can conclude that 3D surface models construction for upper incisors is reproducible. 3D shape analysis using CBCT images allows a phenotypic characterization of incisor root morphology.

Root length and alveolar bone level of impacted canines and adjacent teeth after orthodontic traction: a long-term evaluation

OBJECTIVE

The aim of this retrospective study was to evaluate the long-term effects of orthodontic traction on root length and alveolar bone level in impacted canines and adjacent teeth.

MATERIAL AND METHODS

Sample consisted of 16 patients (nine males and seven females), mean initial age 11 years and 8 months presenting with unilaterally maxillary impacted canines, palatally displaced, treated with the same surgical and orthodontic approach. Teeth from the impacted-canine side were assigned as Group I (GI), and contralateral teeth as control, Group II (GII). The mean age of patients at the end of orthodontic treatment was 14 years and 2 months and the mean post-treatment time was 5 years and 11 months. Both contralateral erupted maxillary canines and adjacent teeth served as control. Root length and alveolar bone level (buccal and palatal) were evaluated on cone-beam computed tomography (CBCT) images. The comparison of root length and alveolar bone level changes between groups were assessed by applying paired t-test, at a significance level of 5% (p<0.05).

RESULTS

There were no statistically significant differences in root length and buccal and palatal bone levels of canines and adjacent teeth among groups.

CONCLUSIONS

Impacted canine treatment by closed-eruption technique associated with canine crown perforation, has a minimal effect on root length and buccal and palatal alveolar bone level in both canine and adjacent teeth, demonstrating that this treatment protocol has a good long-term prognosis.

Cone-beam computed tomography for the assessment of root-crown ratios of the maxillary and mandibular incisors in a Korean population

Objective

This retrospective, cross-sectional study aimed to establish reference data for normal crown and root lengths and the root–crown ratios (R/C ratios) for the mature maxillary and mandibular incisors in a Korean population by using cone-beam computed tomography (CBCT).

Methods

We included 672 Korean patients (141 men and 531 women; mean age, 27.2 ± 7.7 years) who underwent CBCT examinations during various dental treatments. Crown and root lengths and the R/C ratios of the maxillary and mandibular incisors were measured using CBCT data, which were analyzed to detect significant differences between demographic factors as well as sagittal and vertical skeletal or occlusal relationships.

Results

Teeth of the same type in each half-arch were symmetrical. The mean R/C ratios varied from 1.1 to 1.2 for the maxillary incisors and from 1.3 to 1.4 for the mandibular incisors. Crown and root lengths were greater in men than in women, regardless of tooth type. Root lengths and R/C ratios for the mandibular incisors were significantly greater in patients with skeletal Class II malocclusion or an excessive overjet than in the other patients. The R/C ratios for the mandibular incisors were lower in patients with an open bite than in those with a normal or deep bite. Moreover, the R/C ratios for the mandibular incisors increased with age.

Conclusions

The data obtained in our study can serve as reference values for crown and root lengths and the R/C ratios for the maxillary and mandibular incisors in the Korean population.

3D reconstruction images of cone beam computed tomography in dental medicine application: A case study and mini-review

Dental cone beam computed tomography (CBCT) is a new approach in diagnosis and predication of various dental diseases, including trauma, congenital defects, tumors and inflammatory. In this study, we reported the outcome of CBCT for a complicated case of malocclusion, accompanied with tooth loss and periodontitis. A combined application of CBCT with 3D-static images and rotated reconstruction images is reviewed as a systematic model in diagnosis, treatment and progonsis of a complex malocclusion.

Influence of Invisalign treatment with interproximal enamel reduction (IER) on bone volume for adult crowding: a retrospective three-dimensional cone beam computed tomography study

Background

The aim of this study was to use three-dimensional datasets to identify associations between treatment for adult crowding using Invisalign and interproximal enamel reduction (IER) and changes in the bone volume.

Methods

A total of 60 digital cone beam computed tomography (CBCT) scans from 30 patients (28 women, two men; 30 CBCTs pretreatment, 30 posttreatment) were examined retrospectively in order to record bone volume three-dimensionally before and after treatment. The patients’ average age was 36.03 ± 9.7 years. The data were collected and analyzed using the computer programs Mimics 15.0 and OsiriX. Differences in bone between T0 and T1 were analyzed with IBM SPSS 21.0 using the Wilcoxon test for paired samples.

Results

Analysis of the orovestibular bone volume showed highly significant changes (bone change P <0.001) only in the mandible where more expansion of the dental arch was carried out using proclination or protrusion. The bone lamella was thinner buccally and thicker lingually. In general, bone increases in the oral direction were slightly greater than bone losses in the vestibular direction. No significant changes were detected in the maxilla (bone change P = 0.13). Significant vertical bone loss in the bone height was detected in both the maxilla and the mandible. The largest bone loss was observed in the vestibular direction in the mandible, at a high level of significance (P <0.001).

Conclusions

Particularly in the mandible, therapeutic reduction of the vertical and sagittal bone volume shows that caution should be used in the treatment of tertiary crowding with proclination and expansion. The cortical walls appear to represent the limits for orthodontic tooth movement, at least in adult female patients.