Radiographic predictors for maxillary canine impaction

Does Current Evidence Support the Discussion Around the Guidance Theory? A Systematic Review and Meta-Analysis on the Association Between Maxillary Lateral Incisor Agenesis and Displacement or Impaction of the Permanent Canine

Palatal impaction of the maxillary canine is commonly considered as a genetic condition, while the lateral incisor root has been suggested to guide maxillary permanent canine eruption. This review assessed whether agenesis of the maxillary lateral incisor is associated with eruption disturbances of the maxillary canine (displacement or impaction). Unrestricted searches in six databases for observational case-control human studies until May 2024 assessing eruption disturbances of the permanent maxillary canine in conjunction with permanent maxillary lateral incisor agenesis were performed. Study selection, data extraction and risk-of-bias assessment with the Joanna Briggs Institute's tool were performed in duplicate. Random-effects meta-analyses of odds ratios (ORs) with their 95% confidence intervals (CIs) were performed, followed by meta-regressions and sensitivity analyses. Seventeen reports pertaining to 17 case-control studies were included covering 10,155 patients (11.6 year-old/46% male on average). Maxillary lateral incisor agenesis was associated with eruption disturbance of the maxillary canine (17 studies; OR = 3.88; 95% CI = 2.05-7.34; p < 0.001; I 2 = 58). Lateral incisor agenesis was more associated with canine displacement (7 studies; OR = 7.56; 95% CI = 2.10-27.18; p = 0.008; I 2 = 57) and to a lesser degree with canine impaction (10 studies; OR = 2.39; 95% CI = 1.28-4.48; p = 0.01). No significant effects of patient age or sex were seen, and the results were robust to study design and precision. The quality of evidence was low due to the inclusion of observational case-control studies with methodological issues and residual confounding. Evidence indicates that permanent maxillary lateral incisor agenesis is associated with eruption disturbances of the permanent maxillary canine, including mainly displacement, but also impaction. Trial Registration: PROSPERO database number: CRD42024549898.

Analysis of the Relationship Between Unilateral Posterior Crossbite and Alterations in the Eruptive Trajectory of Maxillary Canines, the Occlusal Plane, and the Inclination of the Labial Commissure

OBJECTIVES

The aim was to establish whether there is a relationship between the presence of unilateral posterior crossbite (u-PCB) and the mesio-distal inclination of permanent upper canines, the angulation of the occlusal plane, or the labial commissure inclination in children.

METHODS

A cross-sectional association study was conducted. Panoramic radiography was used to measure the inclination of the canines and the occlusal plane, and frontal rest photography was used to measure the inclination of the labial commissure. The measurements were performed with tpsDig264 software version 2.25, 2016, Ecology & Evolution, SUNY), and the data obtained were analyzed with SPSS 22.0 software, using ANOVA and Kruskal-Wallis tests for the statistical analysis.

RESULTS

A total of 106 patients with u-PCB and 41 patients in the control group were studied. No statistically significant differences were observed in the inclination of the right and left canines in patients with u-PCB compared to patients in the control group. There is a relationship between the presence of u-PCB and the inclination of the occlusal plane. No statistically significant differences were observed in the inclination of the labial commissure in patients with u-PCB compared to patients in the control group.

CONCLUSIONS

There is no relationship between the presence of u-PCB and the alteration in the eruptive trajectory of the permanent upper canines or in the inclination of the labial commissure. However, a relationship between the presence of u-PCB and altered occlusal plane inclination was found.

Possible link between the preferential unilateral chewing side and eruptive guidance of the maxillary canine germ : Cross-sectional study on panoramic radiographs

AIM

To determine whether unilateral preferent chewing (UPC) affects the position and angulation of the permanent maxillary canine germ on the preferred side.

MATERIALS AND METHODS

In a retrospective cross-sectional study, medical records from children 7.91(± 0.8) years old with unilateral preferred chewing side and unilateral posterior crossbite were selected. The position of the maxillary canines was analysed by measuring the following angles and distances: the angles formed between the canine axis and the midline (PS; potential impact range > 15°), and that between the canine axis and the bicondylar line (W; potential impact range < 75°). In addition, the canine's position with respect to the lateral incisor (EK; potential impact range > II) and the distance between the canine cusp and the occlusal plane (CCOP potential impact range > 10 mm) were measured.

RESULTS

The final sample consisted of 106 radiographs; thus, a total of 212 maxillary canines were analysed. Tooth angulation on the preferred chewing side was higher for the angle PS with an average angle of 13.88° (± 7.56) and its position was more frequently found in sector II (49.1%), according to the EK analysis, compared to its contralateral that had an average of 11.75° (± 10.13) for the PS angle and a frequency of 67% in the sector I (p < 0.05 in both analyses). The data obtained for the angle W resulted in an average of 76.12° (± 9.09), while on the contralateral side it was 77.16° (± 12.56; p = 0.012). Lastly, according to the CCOP analysis, the preferred chewing side measured on average 15.3 mm (± 2.4), while on the nonpreferred side it was 15.19 mm (± 2.43; p = 0.143).

CONCLUSIONS

Based on this research, UPC seems to have a certain unfavourable influence on canine position and angulation. Thus, this is another factor to consider in decision-making regarding early treatment of this development disorder.

Evaluation of maxillary transverse dimensions in individuals with a unilaterally impacted canine

INTRODUCTION

The aim of this study was to investigate the maxillary width within individuals with a unilaterally impacted maxillary canine and to determine any association between the impacted canine location and some canine-related variables.

METHODS

A cross-sectional analytical study using a split-mouth design included 22 CBCTs of individuals with unilaterally impacted maxillary canines (a total of 44 sides). The maxillary width was measured and compared in both impacted and non-impacted sides at various levels: basal, alveolar, and dental. The following canine-related variables were analyzed and compared with impaction location: impacted canine angulation, cusp tip distance from the occlusal plane, type of impaction (vertical or horizontal), presence of root resorption, deciduous teeth, or adjacent teeth transposition. Significance was considered at P < 0.05.

RESULTS

There was a significant reduction in maxillary width on the impacted side at the following levels: maxillary first premolar alveolar crest in both coronal and axial sections, dental width measured from the central fossa of maxillary first molar to the midline, and width measured from the canine cusp tip to the midline. Moreover, the distance from the palatally impacted canine cusp tip to the occlusal plane was statistically significantly lower (7.6 ± 1.5 mm) compared to buccal (10.8 ± 3.3 mm) and mid-alveolus (12.0 ± 3.9 mm) impaction, (P values = 0.02).

CONCLUSIONS

There was a significant association between canine impaction and reduction in the maxillary width at least on the dental level. The palatally impacted canine cusp tip was significantly closer to the occlusal plane compared to the buccal and mid-alveolar impaction.

Radiographic assessment of unerupted permanent maxillary canines and their relationship to the phases of dentition in mixed dentition Spanish children: a retrospective cross-sectional study

PURPOSE

Evaluate if there is a significant association between the position and inclination of the unerupted maxillary canine measured on a panoramic radiograph, and their relationship to gender, age of the patient and stage of dentition.

METHODS

138 panoramic radiographs were examined for this retrospective cross-sectional investigation. Only patients living in Madrid, Spain with mixed dentition were included. These measurements were performed on radiographs, considering the inclination and position of the maxillary canines with regards to the midline, and height with respect to the occlusal plane. Spearman's correlation coefficient was used to analyze the relation among the canine angle and height. p < 0.05 was considered to be significant.

RESULTS

The prevalence of patients with an altered canine angle was 10%, while 43.5% had an apparently abnormal position (overlapping at least half of the adjacent lateral incisor root). No statistically significant association was found between these two variables. In 5% of the patients, the maxillary canine was with an anomalous angle and position. Significant differences were obtained when comparing canine height between children with ectopic canines and normal canines (p = 0.032).

CONCLUSION

No significant association was found between the position and inclination of the unerupted maxillary canine in our sample. Ectopic maxillary canines had a higher incidence in girls, although we did not find statistically significant differences between genders. We observed a higher prevalence of abnormal position and inclination of the permanent maxillary canine in early mixed dentition. Maxillary canines were significantly elevated, further from the occlusal plane, in children with ectopic canines.

Characteristics of Unilaterally Impacted Maxillary Canines and Effect on Environmental Tissues: A CBCT Study

BACKGROUND

The prognosis of orthodontic treatment for a patient with impacted canine teeth can be affected by many factors and understanding some of the characteristics of impacted teeth can increase the effectiveness and reduce the duration of treatment. This study aims to explore the effects of positions and dentoalveolar morphological characteristics of impacted maxillary canines on the prognosis of orthodontic treatment.

METHODS

In this study, forty-six adolescent individuals who applied for treatment of impacted teeth were divided into three groups: CC (no impacted maxillary canine group), BC (unilateral buccally positioned impacted maxillary canine group), and PC (unilateral palatally positioned impacted maxillary canine group). The impacted canine and adjacent teeth were evaluated in terms of position, angulation, inclination, mesiodistal and buccolingual widths, root length, dilaceration angle, and root resorption.

RESULTS

The mean values of U3 Ang (angulation of the maxillary impacted canine) and U3/U2 angles (maxillary impacted canine and lateral incisor angle) were statistically significantly higher in the BC and PC groups (p < 0.001). The mean values of U2 RL (lateral incisor root length) and U3 RD (canine root dilaceration angle) were statistically significantly lower in the BC and PC groups.

CONCLUSIONS

The results of this study suggest that shorter root lengths and increased angulation values may lead to the ectopic eruption of canines. The higher canine angulations in the PC group increase the degree of root resorption.

Early prevention of maxillary canine impaction: a randomized clinical trial

OBJECTIVES

To investigate the effect of three interceptive measures (slow maxillary expansion (SME) with removable plates (1), extraction of both upper deciduous canines (DC) (2) and no intervention (3)) on maxillary canine (MC) position in patients with early mixed dentition (EMD) and lack of upper arch space. These three groups were additionally compared to a control group (4) with adequate upper arch space.

NULL HYPOTHESIS

None of the studied strategies outperforms the others regarding improvement of MC position.

TRIAL DESIGN

Four-arm parallel group prospective randomized controlled trial.

PARTICIPANTS

Patients in EMD with at least one impacted MC, non-resorbed DC, and no crossbite.

INTERVENTIONS

Patients with a lack of space were randomly distributed to protocols (1), (2), and (3).

PRIMARY OBJECTIVE

To assess the change in MC position after 18 months follow up.

SECONDARY OBJECTIVES

To assess canine eruption and need for orthodontic intervention within 18-60 month follow up.

OUTCOME ASSESSMENT

Five variables defined canine position: sector, canine-to-midline angle, canine-to-first-premolar angle, canine-cusp-to-midline distance, and canine-cusp-to-occlusal-plane distance on two panoramic radiographs at 0 (T1) and 18 months (T2). Mean differences between groups were compared with linear mixed models, corrected for age and sex.

RANDOMIZATION

The patient allocation sequence was generated by an electronic randomization list.

BLINDING

The operator taking the measurements was blinded to the groups.

RESULTS

Seventy-six patients were included (142 canines, mean age 9.2 years, 60.5 per cent male, mean follow up 1.9 years), 19, 17, 14, and 26 patients in groups 1-4, respectively. In absence of dental crossbite in patients with lack of space and impacted MC, SME improved the canine sector (P = 0.040), compared to no intervention (P = 0.028). Canine-to-midline angle and canine-to-occlusal-plane distance significantly decreased in all groups at T2. Extraction improved the canine-to-first-premolar angle at T2 more than other strategies in EMD (P = 0.015-0.000).

CONCLUSIONS

Early SME improves the canine sector and reduces the need for major orthodontic intervention in the long term. Taking a first panoramic radiograph in EMD allows timely intervention in case of MC impaction.

TRIAL REGISTRATION NUMBER

NCT05629312 (Clinical Trials.org). Trial status: follow up ongoing.

Comparison of root apex's position between unilateral and bilateral palatally impacted canines: A pilot study

INTRODUCTION

The purpose was to determine whether the location of the root apices of unilateral palatally impacted canines differs from that of bilateral palatally impacted canines using cone-beam computed tomography.

METHODS

The subjects were divided into 3 groups: a bilateral palatally impacted canine group (BPG; n = 28), a unilateral palatally impacted canine group (UPG; n = 28), and a control group (CG; n = 28) that included contralateral normally erupted canines in the UPG. After selecting the root apex in the onDemand3D program, 3-dimensional coordinates were extracted. These 3-dimensional coordinates were converted using the MATLAB program to 2-dimensional coordinates via projection on the palatal plane. Procrustes analysis was used to superimpose these 2-dimensional coordinates. The x- and y-coordinates of the root apices were used to measure the distance between the origin and root apex.

RESULTS

The distance between the root apex of the canine and the origin was 17.43 ± 1.78 mm in BPG, 17.96 ± 1.87 mm in UPG, and 13.96 ± 0.95 mm in CG. There was no statistically significant difference between UPG and BPG. However, there was a statistically significant difference between the CG and impacted groups (UPG and BPG). The same results were found for the x- and y-coordinates.

CONCLUSIONS

The location of the root apices of unilateral palatally impacted canines is similar to that of bilateral palatally impacted. The location of root apices of palatally impacted canines differs from that of normally erupted canines.

Monitoring cone-beam CT radiation dose levels in a University Hospital

OBJECTIVE

To present patient dose levels for different CBCT scanners, acquired by a dose monitoring tool in a University Hospital, as a function of field of view (FOV), operation mode, and patient age.

METHODS

An integrated dose monitoring tool was used to collect radiation exposure data [type of CBCT unit, dose-area product (DAP), FOV size, and operation mode] and patient demographic information (age, referral department) performed on a 3D Accuitomo 170 and a Newtom VGI EVO unit. Effective dose conversion factors were calculated and implemented into the dose monitoring system. For each CBCT unit, the frequency of examinations, clinical indications, and effective dose levels were obtained for different age and FOV groups, and operation modes.

RESULTS

A total of 5163 CBCT examinations were analyzed. Surgical planning and follow-up were the most frequent clinical indications. For the standard operation mode, effective doses ranged from 35.1 to 300 µSv and 9.26-117 µSv using 3D Accuitomo 170 and Newtom VGI EVO, respectively. In general, effective doses decreased with increasing age and FOV size reduction.

CONCLUSIONS

Effective dose levels varied notably between systems and operation modes.Operation mode selection and FOV size were indication-oriented, with larger FOV sizes election serving surgical planning and follow-up. Seeing the influence of FOV size on effective dose levels, manufacturers could be advised to move toward patient-specific collimation and dynamic FOV selection. Systematically monitoring patient doses could be recommended for steering future CBCT optimization.

Unilateral vs Bilateral Maxillary Canine Impaction: A Cone-Beam Computed Tomography Study of Patterns and Associations

AIM

This retrospective study aimed to compare and evaluate the pattern of maxillary canine impaction and its association with other anomalies using cone-beam computed tomography (CBCT).

METHODS

A total of 59 CBCT records of patients (ages 12 and up) were divided into two groups: A total of 35 subjects with unilateral canine impactions and 24 subjects with bilateral canine impactions. The CBCT data were analyzed for the measurement of qualitative and quantitative variables.

RESULTS

In unilateral canine impaction, the mesiodistal (MD) width of the central incisors and the nasal cavity (NC) width were wider (p < 0.05). The canine-palatal plane (U3-PP) distance was significantly longer in bilateral canine impaction (p < 0.05). The distance of the impacted canines from the palatal and mid-sagittal planes, the anterior dental arch width, and the maxillary skeletal width changed significantly with the position of the impacted canines (p < 0.05). Males had 0.185 odds of presenting with a bilateral canine impaction as compared to females (p = 0.025). The odds of having bilateral canine impaction with a longer canine-midsagittal plane (U3-MSP) distance was 1.30 (p = 0.003).

CONCLUSION

The findings indicate a gender predilection with females showing a greater prevalence of bilateral canine impaction. Supernumerary teeth were associated with unilateral impacted canines and lower canine impaction with bilaterally impacted canines.

CLINICAL SIGNIFICANCE

Anomalies in the form of the maxillary central and lateral incisors, distance from the maxillary canine to the palatal plane and the mid-sagittal plane, NC width, maxillary skeletal width, and gender, are the best discriminating parameters between unilateral and bilateral canine impactions.

Root morphology of lateral incisors adjacent to impacted maxillary canines: A cone-beam computed tomography retrospective cross-sectional study

INTRODUCTION

To compare the root morphology of the maxillary lateral incisors (MLIs) adjacent to an impacted (IMC) versus non-impacted maxillary canine (non-IMC).

MATERIALS AND METHODS

This cross-sectional study included cone beam computed tomography (CBCT) images derived from 154 subjects (with unilateral/bilateral impacted maxillary canines or without canine impaction). Each MLI was considered as a unit of analysis. Thus, the study group included 122 MLIs adjacent to impacted maxillary canine (IMCG) and the control group included 122 MLIs adjacent to a non-impacted maxillary canine (CG). Groups were matched by age, sex and evaluation side. Root length, root dilaceration angle and root convergence angle were evaluated in both the coronal and sagittal planes. Comparisons between groups were made with Student's t-test and the chi-square test with Bonferroni correction (P<0.008, P<0.01, respectively).

RESULTS

The root measurements of the MLIs showed some significant differences between the groups. The coronal root length was 0.52mm shorter but not highly significant (P=0.032), the coronal root dilaceration angle was 7.51° smaller (P<0.001), and the coronal root convergence angle was 1.28° greater (P<0.001) in the IMCG compared to the CG. The orientation of root dilaceration in the MLIs showed significant differences between the groups: it was mostly distopalatal in the GC (87.5%), to a lesser extent in the IMCG (58.9%) and also mesiopalatal in the IMCG (22.3%), (P=0.001).

CONCLUSIONS

The root morphology of MLIs adjacent to an IMC showed a tendency of shorter length, smaller root dilaceration and greater root convergence in the coronal section than MLIs adjacent to a non-IMC.

Relationship between palatally impacted canines and dimensions and morphology of sella turcica: A cone-beam computed tomography study

INTRODUCTION

This study aimed to analyze the association of unilateral and bilateral palatal canine impaction with the dimensions and morphology of sella turcica from 3-dimensional cone-beam computed tomography (CBCT) images.

METHODS

CBCT images of patients with bilateral (BPI) (n = 12; 9 female 3 male; 20.75 ± 5.88 years) and unilateral (UPI) (n = 35; 22 female 13 male; 19.28 ± 5.57 years) palatally impacted canines were compared with a control group (n = 56; 34 female 22 male; 20.82 ± 4.88 years). Linear measurements regarding sella turcica were made, and its morphologic variations were categorized. Two group comparisons were made with the Student t test or Mann-Whitney U-test, whereas one-way analysis of variance or Kruskal-Wallis tests were used for multiple group comparisons. Categorical variables were compared using the chi-square or Fisher exact test as appropriate. The binary logistic regression analyses and correlations using Spearman or Pearson correlation analyses were used to determine associations between variables (P <0.05).

RESULTS

Sella diameter was significantly smaller in the BPI group compared to UPI and control groups. There was a significant association between sella diameter and BPI when compared with the control group (χ2[1] = 9.150; P = 0.008). There were no significant differences between groups in the distribution of sella turcica morphology.

CONCLUSIONS

Despite the similar genetic origin of the sella turcica region and teeth, the association of palatal canine impaction with dimensions and morphology of sella turcica was weak. Both local and genetic factors might contribute to the ectopic position of the canine.

Risk Prediction of Maxillary Canine Impaction among 9-10-Year-Old Malaysian Children: A Radiographic Study

BACKGROUND

Early diagnosis and interceptive treatment of the maxillary canine impaction is crucial as it reduces treatment complexity and decreases complications and adverse outcomes. Aim and Objectives. To determine the mean maxillary canine position among 9-10-year-old children and predict the risk of impaction of the maxillary canines. Methodology. Panoramic radiographs (PANs) of 289 healthy children aged between 9 and 10 years were observed where the average position of maxillary canines was related to the lateral incisor, sector locations, and angulations to the bicondylar line were traced. The average position was obtained by using descriptive statistics. One sample Wilcoxon signed-rank test is done to predict the risk of canine impaction by comparing the data obtained to the average position from prior studies.

RESULTS

A total of 289 PANs (126 males and 163 females) were utilized for the analysis. The findings showed that the average position of the maxillary canines in our population was statistically different from the average position of nonimpacted canines in previous studies. However, on average, more than 85% of canines in our population were still located within the safe range of satisfactory position, with females showing slight predominance outside of the acceptable range. The mean scores of the angles between the right canine and lateral incisor were significantly higher among females than males (p = 0.001). Similarly, females had a significantly higher mean angle of the left canine than males (p < 0.001). In regard to the angles between the bicondylar line and permanent maxillary canine, the mean scores were not significantly different (p > 0.05) on both the left and right side.

CONCLUSION

There is a low risk of impaction of maxillary canines in the Malaysian population. However, more retrospective studies using more radiographic and clinical indicators need to be done to confirm the risk of impaction further.

Root Resorptions on Adjacent Teeth Associated with Impacted Maxillary Canines

Aim: Through the use of CBCT images, many unidentified features of impacted canines can be easily resolved. The potential collision of impacted maxillary canines and adjacent teeth could lead to root resorption (RR). The aim of this study is to examine the prevalence, location and severity of RR on adjacent teeth caused by impacted maxillary canines and the association between the adjacent teeth and the features of maxillary impacted canines on CBCT. Methods: This study examined 89 subjects with 108 maxillary impacted canines, having had no previous orthodontic treatment (mean age: 18.3 ± 4.1 years). The following impacted-canine-related parameters were analyzed on the CBCT images: location; RR levels on adjacent teeth; occlusal line and midline distances of impacted canines; and the angulations of impacted canines to the midline, lateral incisor and occlusal line. Logistic regression was used to evaluate the association between RR and the measured parameters on CBCT. Results: In this study, we found that the majority of our patients with impacted maxillary canines were female (62.5%). Of the total 108 maxillary impacted canines, 60.2% resorbed the adjacent teeth of the affected quadrants. Lateral incisors were the most affected (34.3%). The mean age of subjects with RR was 16.7 ± 3.5 years. The frequency of RR was statistically significantly higher in female subjects (40.4%). Slight RR was the most frequent (30.5%) and the highest incidence noted at the apical third of the root (29.6%). Regarding the impacted maxillary canine angulation to the midline and adjacent tooth, higher values of angulation caused severe forms of RR (p < 0.05). Conclusion: The sensitivity of CBCT allows for the accurate diagnosis of the location and the degree of RR, alongside the angulation and distance of impacted canines to adjacent teeth. The association between the linear and angular features of the impacted maxillary canines and RR was confirmed.

Decision-Making Criteria of Odontectomy or Surgical Exposure in Impacted Maxillary Canine Based on Treatment Difficulty Index Modification

OBJECTIVE

 Canine impaction is a difficult condition to treat, and it usually necessitates a combination of surgical exposure and orthodontic traction or surgical extraction. An accurate assessment of the maxillary canine's position can help determine the severity of the impaction, the difficulty of therapy, and the treatment's prognosis.

MATERIALS AND METHODS

 A total of 55 impacted canines were studied and selected retrospectively. Difficulty indexes were used to measure the severity of impaction with pretreatment panoramic radiographs.

STATISTICAL ANALYSIS

 Pearson correlation was used to test the validity of the difficulty index modification score. Regression statistical analysis was used to evaluate any correlation between total scoring from each index with surgical treatment.

RESULTS

 The validity test on the variable modification index score showed a valid value (p = 0.000). According to both treatment difficulty and modification index, odontectomy group showed higher mean of total scoring than surgical exposure group. Treatment difficulty and modification index showed a significant correlation with surgical treatment (p = 0.003 and p = 0.001).

CONCLUSIONS

 The higher the severity of canine impaction, the greater is the possibility of odontectomy than surgical exposure. Both indexes can consider to be used in determining surgical treatment planning.

Prediction methods of maxillary canine impaction: a systematic review

OBJECTIVE

To describe and assess the available evidence of prediction methods of maxillary canine impaction (MCI).

MATERIAL AND METHODS

A systematic search was conducted through PubMed, Cochrane Library, Embase, EBSCOhost, Scopus, ScienceDirect, Bireme and Scielo until December 2020. This systematic review was conducted according to the PRISMA statement. The methodology of the selected studies was assessed using the Quality Assessment Tool for Diagnostic Accuracy Studies (QUADAS-2).

RESULTS

A total of 2391 articles were identified in the first approach and after a 2-phase selection, 11 studies were included in qualitative analysis. Prediction methods were constructed using equation-based models, geometric measurements and computational methods from clinical and imaging data to predict palatal/buccal MCI. The quality of evidence was low to moderate due to the presence of risk of bias in most of the studies included. Three cohort studies with the best methodological quality proposed prediction models based on geometric measurements, canine position and facial growth pattern that would allow predicting MCI from CBCT, lateral and panoramic radiographs.

CONCLUSIONS

The evidence is limited and most of the studies present a low methodological quality. However, it is possible to suggest that some prediction methods based on the position of the canine and facial growth pattern could predict palatal/buccal MCI in mixed dentition. Cohort studies with better methodological quality and long-term follow-up are needed to better validate a prediction model.

Radiographic predictors of maxillary canine impaction in mixed and early permanent dentition - A systematic review and meta-analysis

BACKGROUND/OBJECTIVE

Early diagnosis and the interception of potential impaction is the most desirable approach for management of impacted canines. Several radiographic predictors have been previously proposed to predict canine impaction. Hence the aim of this systematic review was to identify the most effective radiographic predictors of maxillary canine impaction.

SEARCH METHOD

The following databases were searched: PubMed via Medline, Science Direct, LILACS, Cochrane library and Ovid MEDLINE. All comparative studies including observational and interventional studies that compare a canine impacted group versus a control group were included. The primary outcome assessed were the radiographic predictors used for diagnosis of maxillary canine impaction.

RESULTS

Thirteen articles were included in this systematic review. The most commonly used parameters are sector classification, angle formed by the long axis of the canine and the midline, angle formed by the long axis of the canine and the lateral incisor, angle formed by the long axis of the canine and the occlusal plane, and perpendicular distance between the canine cusp tip to the occlusal plane and to the midline. Meta-analysis indicated that the angle formed by the long axis of the canine and the midline with a value of 19.9° and above (95% CI of 6.68 to 33.15), the angle formed by the long axis of the canine and the lateral incisor with a value of 20.01° and above (95% CI of 7.52 to 32.51) favoured canine impaction.

CONCLUSIONS

With eleven of the thirteen articles showing a low risk of bias/good quality, it can be concluded that canine impactions can be predicted using various linear and angular parameters measured on different radiographs (orthopantomograms, lateral cephalograms, postero-anterior cephalograms and cone-beam computed tomography). However, further three-dimensional studies are required to accurately predict and diagnose canine impactions.

REGISTRATION

The study protocol was registered on the International Prospective Register of Systematic Reviews (Reg no: CRD42020200518).

A new guide using CBCT to identify the severity of maxillary canine impaction and predict the best method of intervention

OBJECTIVE:

This study aimed to test the intra and inter-rater reliability, reproducibility, and validity of a new guide called the “Cone Beam Computed Tomography-Maxillary Canine Impaction (CBCT-MCI),” designed to assess the position, severity, and predictability of the maxillary canine impaction (MCI) treatment intervention using Cone Beam Computed Tomography (CBCT).

MATERIALS AND METHODS:

This study is a retrospective radiographic review of 44 patients with unilateral or bilateral MCI. A total of 56 maxillary impacted canines’ CBCT radiographs were analyzed using the new CBCT-MCI guide, with each of its 10 items scored. The total scores of the 10 items were then compared to a scale to predict the best treatment intervention of MCI: normal spontaneous eruption, surgical-orthodontic traction, or surgical extraction. Radiologists and orthodontists have developed, tested, and retested the CBCT-MCI guide on the same 56 maxillary impacted canines using CBCT radiographs to check its reliability and reproducibility using the Kappa coefficient. Furthermore, the validity of this guide was tested by comparing the predicted best treatment intervention with the actual treatment administered to the assessed impacted maxillary canine using the Kappa coefficient and percentage of agreement using cross-tabulation.

RESULTS:

The result of this study showed significantly strong Kappa values of intra-rater agreement (k = 0.91, (P < 0.0001) and inter-rater agreement (k = 0.84, P < 0.0001). Furthermore, testing the relationship between the two MCI treatment interventions using cross-tabulation, the agreement percentages between the predicated and actual treatment plans of the assessed MCI ranged between 70% and 95.5% with a significantly strong Kappa value (k = 0.82, P < 0.0001).

CONCLUSIONS:

This study suggests that the CBCT-MCI guide is capable of producing accurate, reliable, and reproducible results in assessing and predicting the type of orthodontic treatment intervention of MCI in a simple, quick, and efficient way.

Interventions for impacted maxillary canines: A systematic review of the relationship between initial canine position and treatment outcome

BACKGROUND

The objective of this review was to critically assess the existing literature on the relationship between the initial position of impacted canines and treatment outcomes.

METHODS

We performed a systematic review of the available literature until February 2020 using the MEDLINE, Cochrane Central, Web of Science and PubMed databases. Prospective and retrospective studies (randomized controlled trials [RCTs], cohort studies, longitudinal follow-up studies) considering impacted maxillary canines that were orthodontically and/or surgically treated, and clearly reporting the initial position using 2D and/or 3D classifications, were included if they assessed at least one of the following: treatment success, treatment duration, number of treatment visits, radiographic outcome, periodontal health, esthetics and/or treatment complications. The included studies were assessed for risk of bias according to the Cochrane guidelines.

RESULTS

Seventeen studies were reviewed (2 RCTs and 15 non-RCTs). The included studies enrolled a total of 1247 patients with an average age of 14.1 years and a total of 1597 impacted canines. Various causal relationships were detected between the success of treatment modalities and the initial state of the impacted canine (bucco-palatal position, vertical position, canine angulation, root development).

DISCUSSION

Evidence, though limited, suggests that a higher alpha angle, higher vertical position and more mesial sector of the impacted canine are related to less successful interceptive and active treatment solutions, prolonged treatment time and inferior outcomes.

Effectiveness of 2D radiographs in detecting CBCT-based incidental findings in orthodontic patients

Some craniofacial diseases or anatomical variations are found in radiographic images taken for other purposes. These incidental findings (IFs) can be detected in orthodontic patients, as various radiographs are required for orthodontic diagnosis. The radiographic data of 1020-orthodontic patients were interpreted to evaluate the rates of IFs in three-dimensional (3D) cone-beam-computed tomography (CBCT) with a large field of view (FOV) and investigate the effectiveness and accuracy of two-dimensional (2D) radiographs for detecting IFs compared to CBCT. Prevalence and accuracy in five areas was measured for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). The accuracies of various 2D-radiograph were compared through a proportion test. A total of 709-cases (69.5%) of 1020-subjects showed one or more IFs in CBCT images. Nasal cavity was the most affected area. Based on the CBCT images as a gold standard, different accuracies of various 2D-radiographs were observed in each area of the findings. The highest accuracy was confirmed in soft tissue calcifications with comprehensive radiographs. For detecting nasal septum deviations, postero-anterior cephalograms were the most accurate 2D radiograph. In cases the IFs were not determined because of its ambiguity in 2D radiographs, considering them as an absence of findings increased the accuracy.

Prediction of spontaneous eruption of palatally displaced canine based on variables measurements in panoramic radiograph: A systematic review

OBJECTIVE

This systematic review was aimed to find out possible predictive variables measured on panoramic radiographs to predict spontaneous eruption of palatally displaced canine (PDC) after interceptive extraction in late mixed dentition.

MATERIALS AND METHODS

Electronic database searches were performed in MEDLINE, Cochrane's CENTRAL, Scopus, and in other sources up to June 2020. Randomized and nonrandomized controlled trials, and pre-post prospective studies without control groups were considered for review. Study selection, data extraction, risk of bias assessment (by RoB 2.0, ROBINS-I, and NHLBI score), and the certainty of evidence evaluation (GRADE approach) were performed during reviewing process. Only qualitative analyses of included literature were done due to presence of between study heterogeneity.

RESULTS

Out of 970 retrieved records, 3 controlled trials and 3 prospective before and after studies without control fulfilled the eligibility criteria and were included in the review. Studies were assessed at low risk to high risk of bias. Overall certainty was moderate to very low. Results shows that PDCs in distal sectors, lower alpha angle, younger subjects, PDCs with less advanced developed root were significantly benefited from interceptive extraction. However, Vertical distance had insignificant roll on eruption prediction.

CONCLUSIONS

Interceptive extraction at younger age, mesial canine crown position (sectors), and mesial inclination of PDC (alpha angulation) are the most important variables predicting the spontaneous eruption of palatally displaced canine. Findings of this review can be utilized to make evidence-based decisions for managing PDCs with diverse sectors and mesial inclinations. However, well designed clinical trials are recommended to strengthen the evidence.

Comparison of Lateral Tooth Volume and Morphology Between Buccally and Palatally Localised Unilateral Impacted Maxillary Canine Cases on Cone-Beam Computed Tomography

ABSTRACT

The aim of this study was to compare the lateral tooth volume and morphology differences between buccally and palatally localized unilateral impacted maxillary canine (IMC) patients with volumetric and linear measurements on cone-beam computed tomography (CBCT) records. CBCT records of 48 individuals with 24-buccally and 24-palatally localized unilateral IMCs were included to the study. The patients comprised 34 females, 14 males, with a mean age of 17.71 (±SD 6.63 years). This split-mouth, retrospective case-control, study consisted of buccally and palatally IMC group, and each group was categorized into 2 sub-groups as impacted and erupted side. Lateral tooth volume, tooth length, mesiodistal-buccolingual crown widths, mesiodistal- buccolingual root widths at cemento-enamel junction (CEJ), at 4 mm apical to CEJ, at 8 mm apical to CEJ, mesiodistal crown-root angle, arch perimeter measurements were performed on CBCT images. The data were analyzed by factorial design repeated measures ANOVA. Bonferroni test was used for post-hoc analysis. The total volume, mesiodistal - buccolingual crown widths, buccolingual root width of lateral incisor at CEJ were statistically smaller in palatally IMC group. The lateral incisor's length, and arch perimeter were statistically shorter, mesiodistal, buccolingual root widths at 8 mm apical to CEJ, and crown-root angle of the lateral were narrower on impacted side than erupted side. The volume and crown widths of lateral incisor are effective in sagittal localization of IMC. The shorter length, narrower apical root morphology and mesially inclined crown-root angle of lateral incisor are noteworthy on impacted sides, regardless of sagittal position of IMC.

Age-related changes in the effect of rapid maxillary expansion on the position of labially impacted maxillary canines: A case-control study

INTRODUCTION

The early diagnosis and interception of potential maxillary canine impaction is the most desirable approach for correcting their path of eruption. However, there is still a lack of evidence regarding the effect of rapid maxillary expansion (RME) on labially impacted canines. This study aimed to investigate the age-related effect of RME on labially impacted maxillary canines in order to reduce the risk of their impaction in the mixed dentition and to examine the proper timing of interceptive treatment.

METHODS

All patients aged 7-10 years were treated with an RME appliance using the same protocol. The distance to the occlusal plane, axis to the midline, and distribution in different sectors-depending on the patients' age-were evaluated for maxillary canines before and after treatment on panoramic radiographs in order to detect changes in the position of the impacted canines. These geometric measurements in the impacted canines were also validated by observing the nontreated canines at each age.

RESULTS

Significant differences existed between the impacted canines and the erupted canines in all 3 categories in all age groups. RME treatment modulated the position of the impacted canines in all age groups. Interestingly, a statistically significant difference before and after RME in all categories was detected in patients aged <8 years. A discriminant analysis also showed a positive association of RME treatment with the risk of labially impacted canines. The standardized regression coefficients showed that the angulation of the maxillary canine was the most important predictor for impaction.

CONCLUSIONS

Our findings indicate that RME treatment in the early mixed dentition was effective for managing labially impacted maxillary canines. An age of 7-8 years with early mixed dentition might be the most appropriate timing for therapeutic intervention on the basis of RME treatment for buccal canine impaction.

Variables to predict spontaneous eruption of palatally displaced permanent canine after interceptive extraction of primary canine: A systematic review and meta-analysis

OBJECTIVE

To evaluate the effectiveness of different diagnostic variables measured on panoramic radiographs (PAN) to predict spontaneous eruption of palatally displaced canine (PDC) after interceptive extraction in late mixed dentition.

MATERIALS AND METHODS

Digital databases (MEDLINE, CENTRAL (Cochrane), Scopus, clinicaltrials.gov, ISRCTN registry) and hand searches were performed up to March 2020. Both randomized and non-randomized controlled trials were considered for the review. Study selection, data extraction, risk of bias assessment (RoB2.0 and ROBINS-I), and the certainty of evidence evaluation (GRADE) were performed according to Cochrane Handbook for Systematic Reviews of Interventions. The random-effects method for quantitative synthesis of dichotomous as well as continuous data was used.

RESULTS

Out of 767 retrieved records, 4 controlled trials fulfilled the eligibility criteria and were included in the review. Studies were assessed at low risk of bias except one. Overall certainty was strong to moderate. PDCs in distal sectors (RR: 1.621; 95%CI: 1.259 to 2.086; P<0.001) and alpha-angle <30° (SMD: -1.350; 95%CI: 1.924 to -0.776; P<0.001) were significantly benefited from interceptive extraction. However, Vertical distance of PDC cusp tip from occlusal plane had statistically insignificant (p: 0.855) roll on eruption prediction.

CONCLUSION

Interceptive extraction at a younger age, initial horizontal localization (sector position), and alpha-angle (initial mesial inclination) are the most important variables predicting the spontaneous eruption of palatally displaced canines. Findings of this review can be utilized to make evidence-based decisions for managing PDCs with diverse sectors and mesial inclinations. However, well-designed clinical trials are recommended to strengthen the evidence.

Evaluation of impacted canines' localization and adjacent lateral incisors' root resorption with orthopantomography and cone-beam computed tomography

OBJECTIVES

In this retrospective study, the frequency and severity of ectopic eruption in the children's permanent canines, changes between the impacted canine parameters on orthopantomography (OPG) taken for routine follow-up were demonstrated. Also, it was aimed to reveal the differences between OPG and cone beam computed tomography (CBCT).

METHODS

Ten thousand (5020 girls, 4980 boys) pediatric patient, were retrospectively investigated for the presence of impacted canine radiographically. OPG and CBCT images of 343 pediatric patients (207 girls, 136 boys) detected impacted canines (n = 432) were evaluated in four steps that the angular and linear measurement, position and status relationships with adjacent anatomical structures were investigated.

RESULTS

The incidence of impacted canine in children was 3.43% (4.02% girls, 2.73% boys). The percentage of adjacent lateral incisor' resorption was 33%. Although the presence of resorption in lateral incisors in contact with a canine was found to be statistically significant (p = 0.02), there was no statistically significant relationship the follicle size and localization of canine in the transverse plane. When images were compared, it was found that there was a statistically significant difference between CBCT and OPG about the parameter of canine angulation to the midline and parameter of canine angulation to the lateral incisor.

CONCLUSIONS

Pediatric dentists should prefer OPG as the first choice for radiographic imaging for the diagnosis of impacted canine at an early age. Follow-up OPGs should be carefully studied with advancing age. The CBCT should be preferred to prevent complications, to view its relationship with adjacent anatomical structures and canine localization in detail.

Risk factors for maxillary impacted canine-linked severe lateral incisor root resorption: A cone-beam computed tomography study

INTRODUCTION

Impacted maxillary canine-linked severe lateral incisor root resorption (SIRRc) is rare, but it greatly influences the survival of the affected teeth. Our study was designed to investigate the risk factors for SIRRc.

METHODS

Eighty-two patients with SIRRc and 81 patients with impacted maxillary canines but without SIRRc were included and evaluated by cone-beam computed tomography in software programs by 1 examiner (H.W.). Age, sex, positions, and dental follicles and angular inclinations of impacted canines were measured in this study. Binary logistic regression was used to analyze the risk factors for SIRRc.

RESULTS

SIRRc was highly related to sex, vertical and mesiodistal position, dental follicles sizes of canines, and intersection angles in 3 dimensions. The regression analysis showed female sex, dental follicles between 1 mm and 3 mm, mesial third and apical third position, vertical angle smaller than 30°, and the relative angle between 30° and 60° were significant risk factors for SIRRc.

CONCLUSIONS

Early diagnosis and treatment for SIRRc are imperative, especially in Asian patients that are female with apically and mesially positioned canines as well as wider dental follicles. Vertical angles and relative angles of impacted canines should also be noticed.

Prediction of maxillary canine impaction based on panoramic radiographs

OBJECTIVES

The objective of this article is to establish a large sample-based prediction model for maxillary canine impaction based on linear and angular measurements on panoramic radiographs and to validate this model.

MATERIALS AND METHODS

All patients with at least two panoramic radiographs taken between the ages of 7 and 14 years with an interval of minimum 1 year and maximum 3 years (T1 and T2) were selected from the Department of Oral Health Sciences, University Hospital Leuven database. Linear and angular measurements were performed at T1. From 2361 records, 572 patients with unilateral or bilateral canine impaction were selected at T1. Of those, 306 patients were still untreated at T2 and were used as study sample. To construct the prediction model, logistic regression analysis was used.

RESULTS

The parameters analyzed through backward selection procedure were canine to midline angle, canine to first premolar angle, canine cusp to midline distance, canine cusp to maxillary plane distance, sector, quadratic trends for continuous predictors, and all pairwise interactions. The final model was applied to calculate the likelihood of impaction and yielded an area under the curve equal to 0.783 (95% CI [0.742-0.823]). The cut-off point was fixed on 0.342 with a sensitivity of 0.800 and a specificity of 0.598. The cross-validated area under the curve was equal to 0.750 (95% CI [0.700, 0.799]).

CONCLUSION

The prediction model based on the above mentioned parameters measured on panoramic radiographs is a valuable tool to decide between early intervention and regular follow-up of impacted canines.

Cone-Beam Computed Tomography in Orthodontics

Unlike patients receiving implants or endodontic treatment, most orthodontic patients are children who are particularly sensitive to ionizing radiation. Cone-beam computed tomography (CBCT) carries risks and benefits in orthodontics. The principal risks and limitations include ionizing radiation, the presence of artifacts, higher cost, limited accessibility, and the need for additional training. However, this imaging modality has several recognized indications in orthodontics, such as the assessment of impacted and ectopic teeth, assessment of pharyngeal airway, assessment of mini-implant sites, evaluation of craniofacial abnormalities, evaluation of sinus anatomy or pathology, evaluation of root resorption, evaluation of the cortical bone plate, and orthognathic surgery planning and evaluation. CBCT is particularly justified when it brings a benefit to the patient or changes the outcome of the treatment when compared with conventional imaging techniques. Therefore, CBCT should be considered for clinical orthodontics for selected patients. Prescription of CBCT requires judicious and sound clinical judgment. The central question of this narrative review article is: when does CBCT add value to the practice of orthodontics? To answer this question, this article presents discussion on radiation dosage of CBCT and other imaging techniques used in orthodontics, limitations of CBCT in orthodontics, justifying the use of CBCT in orthodontics, and the benefits and evidence-based indications of CBCT in orthodontics. This review summarizes the central themes and topics in the literature regarding CBCT in orthodontics and presents ten orthodontic cases in which CBCT proved to be valuable.

Orthopantomographic analysis of the intraosseus position of the maxillary canines

The aim of this work was to analyse the intraosseous position of the maxillary canine in orthodontic patients. It was an exploratory pilot study prior to the next research work to develop a predictive model based on a regression analysis initially including a large number of variables. 105 subjects from 6 to 12 years from both genders were included in this study. Four variables were used. The study showed that there was no marked gender dimorphism concerning the intrabony position of the canine; the latter is quite similar on both sides, and the older the age, the smaller the angulation of the canine. The values obtained for the angulation of the canine, its depth of impaction, its position in relation to the lateral incisor and the premolars, correspond to an average impaction severity and treatment difficulties.

Are panoramic radiographs good enough to render correct angle and sector position in palatally displaced canines?

OBJECTIVES

The early interceptive treatment of palatally displaced canines (PDCs) has for decades been based on their position in panoramic radiographs. In the 1990s, cone-beam computed tomography (CBCT) started to become popular in cases with PDCs. The aims of this prospective study were to evaluate the agreement of PDC sector position and angle to midline between panoramic radiographs and CBCT scans.

METHODS

PDC sector and angle to midline were measured in panoramic radiographs and CBCT scans in 58 consecutive patients with 64 PDCs. Kappa with linear weighting was used to assess the agreement between the measurements of PDC sector position and Bland-Altman limits of agreement to assess the agreement between the PDC angular measurements in the 2 methods.

RESULTS

PDC sector position and angle to midline had systematically higher values in panoramic radiographs compared with those in the CBCT scans. The agreement of sector position between the methods was fair: weighted kappa 0.36 (95% CI 0.24-0.49). The mean difference in angle was almost 7° (95% CI 5.9°-7.9°) higher in panoramic radiographs compared with CBCT.

CONCLUSIONS

Panoramic radiographs overestimate PDC sector and angle to midline position, compared with the use of CBCT scans, but clinically the differences are quite modest. Panoramic radiographs could be considered good enough for rendering PDC position when the need for 3D information is not crucial for treatment planning.

Early identification of permanent maxillary canine impaction: A radiographic comparative study in a Mexican population

Background

Opportune diagnosis, prediction, and interceptive treatment of permanent maxillary canine (PMC) impaction is fundamental for pediatric dentists and orthodontists. In children and young adolescents, diagnostic information obtained from a panoramic radiograph is valuable for the overview and prediction of a potential PMC ectopic eruption into the oral cavity. The aim of the present study was to calculate and compare the prevalence of impaction of PMC in a Mexican pediatric sample (7 to 13 years old), through the use of the Ericson & Kurol (EK/L) and the Power & Short (PS) measurement analyses performed on panoramic radiographs.

Material and Methods

This investigation was a cross-sectional study performed on 515 panoramic radiographs, which were evaluated to assess the intraosseous position of right and left PMC, from patients who had attended our clinic between 2010 and 2017. Both analytical methods were applied on the same radiography. Outcomes from both analysis methods were expressed dichotomously (impacted or non-impacted). Thus, prevalence was calculated from each method, and the difference between them was verified through the Pearson’s Chi-square test.

Results

No statistical difference could be detected between both prevalence rates (p = 0.475). It was found a significant predilection of the condition to the female sex (p = 0.034). Further, the two radiographic methods employed here were highly concordant each other (kappa = 0.92).

Conclusions

Through the EK/L method a PMC prevalence of 5.64% (95% CI = 3.66, 7.62) was obtained, while the PS Method the prevalence was 8.83% (95% CI = 6.38, 11.28). In addition, a significant predilection of canine impaction to the female gender was found.

Key words:Maxillary canine impaction, prevalence, radiographic analyses.

Correlation between radiographic parameters for the prediction of palatally impacted maxillary canines

Objective:

This study aimed to identify radiographic parameters on routine orthopantomograms to aid in early diagnosis of palatally impacted canines.

Design:

Split-mouth case-control study.

Setting:

Single-centre university dental hospital.

Methods:

Thirty-three individuals with palatally impacted canines and non-impacted contra-lateral teeth were recruited. Radiographic variables angle A, angle B, angle C, distance D, sector class and depth of vertical impaction were measured for both groups. Mann–Whitney U test and Spearman’s correlation coefficient were used to analyse significant differences and association between variables with sector class and depth of vertical impaction, respectively. Logistic regression analysis determined radiographic parameters as predictors of palatal impaction.

Results:

Significant differences were seen between sector class, depth of vertical impaction and the radiographic parameters between cases and controls ( P ⩽ 0.001). For cases, strong correlation was found for angle C between the impacted canine and occlusal plane (r = −0.28, P = 0.022) and perpendicular distance D of impacted canine to the occlusal plane (r = 0.81, P ⩽ 0.001) with the depth of vertical impaction. Logistic regression analysis showed the odds of canine impaction increase with an increase in angle B and angle C.

Conclusions:

Our study showed that greater depth of vertical impaction, sector class, increased perpendicular distance and reduced angulation from occlusal plane resulted in palatal impaction of permanent maxillary canines. The odds of palatal canine impaction increase nearly twofold with every 10 increase in angle B and angle C.

Association between maxillary lateral incisors' root volume and palatally displaced canines: An instrumental variables approach to the guidance theory

OBJECTIVES:

To evaluate association and causation between maxillary lateral incisors' (MxI2) apical root volume (ARV) and palatally displaced canines (PDC).

MATERIALS AND METHODS:

In a retrospective cross-sectional study, computed tomography scans of 179 patients with unilateral PDC were analyzed. MxI2 root length and volume on the impaction and eruption side were measured. A mixed logit model was used to infer the association between ARV and PDC and an instrumental variables approach to interpret causality.

RESULTS:

MxI2 root length on the impaction side was shorter in 42%, equal in 33% and longer in 25% of the patients. ARV amounted for 13.5% of total root volume on the impaction and 14.9% on the eruption side. Reduced ARV was significantly associated with the impaction side ( P < .001). The causal effect of ARV on PDC in the instrumental variable approach amounted to less than half of the association in a standard noncausal approach.

CONCLUSIONS:

An association between PDC and reduced MxI2 root length and volume was confirmed. However, the lack of causality did not allow the researchers to draw a conclusion as to whether a reduced ARV is causing PDC or resulting from it; this should be considered in etiologic theories.

Cone-beam CT in paediatric dentistry: DIMITRA project position statement

DIMITRA (dentomaxillofacial paediatric imaging: an investigation towards low-dose radiation induced risks) is a European multicenter and multidisciplinary project focused on optimizing cone-beam CT exposures for children and adolescents. With increasing use of cone-beam CT for dentomaxillofacial diagnostics, concern arises regarding radiation risks associated with this imaging modality, especially for children. Research evidence concerning cone-beam CT indications in children remains limited, while reports mention inconsistent recommendations for dose reduction. Furthermore, there is no paper using the combined and integrated information on the required indication-oriented image quality and the related patient dose levels. In this paper, therefore, the authors initiate an integrated approach based on current evidence regarding image quality and dose, together with the expertise of DIMITRA's members searching for a state of the art. The aim of this DIMITRA position statement is to provide indication-oriented and patient-specific recommendations regarding the main cone-beam CT applications in the pediatric field. The authors will review this position statement document when results regarding multidisciplinary approaches evolve, in a period of 5 years or earlier.

Determinants of maxillary canine impaction: Retrospective clinical and radiographic study

BACKGROUND

The aim of this study is to evaluate determinants of maxillary canine impaction taking into account both canine position related variables and the pattern of facial growth.

MATERIAL AND METHODS

A retrospective clinical and radiographic analysis was carried out on 109 patients aged between 9 and 10 years at the time of first evaluation. At baseline, SN-GoMe angle, the interincisal angle, the canine angle α and the canine distance d were used to characterize canine location and vertical facial growth. At the end of a two years follow up period the eruption state of each canine of each patient was recorded and accordingly classified as erupted or impacted on a clinical and radiographic basis. Univariate and multivariate statistical analyses were performed, including correlation among the studied variables and principal components analysis; several machine learning methods were also used in order to built a predictive model.

RESULTS

At the end of the two years follow up period after the first examination, 54 (24.77%) canines were classified as impacted. Except for Angle α values, there were no statistically significant differences between impacted and erupted canines. The studied variables were not significantly correlated, except for the SN-GoMe Angle and the distance d in the impacted canine group and the angle α and the distance d in erupted canines group. All variables, except for SN-GoMe Angle in erupted canines, have a partial communality with the first two principal components greater than 50%. Among the learning machine methods tested to classify data, the best performance was obtained by the random forest method, with an overall accuracy in predicting canine eruption of 88.3%.

CONCLUSIONS

The studied determinants are easy to perform measurements on 2D routinely executed radiographic images; they seems independently related to canine impaction and have reliable accuracy in predicting maxillary canine eruption. Key words:Canine impaction, Determinants, Facial growth.

Forced eruption of a palatally impacted and transposed canine with a temporary skeletal anchorage device

Treatment of palatally impacted and transposed canines is challenging for both orthodontists and oral surgeons. To treat a maxillary canine impaction without risking damage to adjacent teeth, it is necessary to use cone-beam computed tomography for proper localization and treatment planning. In this case report, a palatally impacted canine was initially retracted distally with a microimplant inserted in the palatal slope and then was moved buccally into its ideal position. The patient's occlusion and smile esthetics were significantly improved after orthodontic treatment.

Three-dimensional evaluation of angular, linear, and resorption features of maxillary impacted canines on cone-beam computed tomography

OBJECTIVES

The aim of this study was to evaluate the localization, angulation, and resorption features of maxillary impacted canines on cone-beam computed tomography (CBCT).

METHODS

This retrospective study examined the CBCT scans of 140 maxillary impacted canines in 102 patients (43 males, 59 females; mean age: 16.25 ± 6.31 years). The following impacted canine-related parameters were analyzed on the CBCT images: impaction side; location; root resorption levels of adjacent teeth; occlusal plane and midline distances of impacted canines; and angulations of impacted canines to midline, lateral incisor, and occlusal plane.

RESULTS

Bilateral canine impaction was found in 38 subjects, and unilateral canine impaction was present in 64 subjects. Severe resorption was found in 14 canines. There were no significant differences between the occlusal plane and midline distances to the impacted canine cusp tip and root apex (p > 0.05). The midline angulation of right maxillary impacted canines was significantly higher than that of left maxillary impacted canines (p < 0.05), while the occlusal plane angulation of left maxillary impacted canines was significantly higher than that of right maxillary impacted canines (p < 0.05).

CONCLUSIONS

Maxillary canine impaction was more frequently seen in female subjects than in male subjects. Lateral incisors were more frequently affected than first premolars, and slight resorption was more frequently seen in adjacent teeth. CBCT assessment of maxillary impacted canines can provide accurate measurements of angular, linear, and resorption parameters.