Early diagnosed impacted maxillary canines and the morphology of the maxilla: a three-dimensional study

Qualitative and quantitative agreement research on three diagnostic methods for maxillary transverse discrepancy

OBJECTIVE

The purpose of this cross-sectional study is to compare the agreement of three diagnostic methods for maxillary transverse deficiency (MTD) across different skeletal malocclusion.

METHODS

Three hundred and sixty patients were categorized into skeletal classes I, II, and III based on the ANB angle and assessed using University of Pennsylvania analysis (UPA), Yonsei transverse analysis (YTA), and Andrews Element III analysis (AEA). The intraclass correlation coefficient (ICC) was used to evaluate quantitative agreement, while Cohen's kappa was used to measure qualitative agreement.

RESULTS

In class I, the AEA showed moderate quantitative agreement with the UPA and AEA (ICC = 0.712), but the UPA and YTA had poor agreement (ICC = 0.404). Qualitatively, UPA and AEA were highly consistent (kappa = 0.896), while YTA and UPA (kappa = 0.371), YTA and AEA (kappa = 0.330) were poor uniformity. For class II, AEA and UPA showed moderate quantitative (ICC = 0.708) and high qualitative agreement (kappa = 0.917), while YTA's qualitative agreement with UPA (kappa = 0.550)/AEA (kappa = 0.544) was moderate. In class III, the AEA again had moderate quantitative agreement with the UPA (ICC = 0.657) and YTA (ICC = 0.580), but the agreement between the UPA and YTA is poor (ICC = 0.408). UPA and YTA were similar in qualitative agreement (kappa > 0.8), and both showed substantial agreement with AEA (kappa = 0.657).

CONCLUSION

1. The incidence of MTD is highest in the skeletal class III group and the lowest in the skeletal class II group. 2. The results of YTA, AEA and UPA for diagnosing MTD are only consistent in patients with skeletal class III. In clinical practice, all three methods can be used to diagnose MTD in patients with skeletal class III malocclusion. 3. For patients with skeletal class I and class II malocclusion, it is recommended to use AEA and UPA for MTD diagnosis.

Predicting the Risk of Maxillary Canine Impaction Based on Maxillary Measurements Using Supervised Machine Learning

OBJECTIVES

To predict palatally impacted maxillary canines based on maxilla measurements through supervised machine learning techniques.

MATERIALS AND METHODS

The maxilla images from 138 patients were analysed to investigate intermolar width, interpremolar width, interpterygoid width, maxillary length, maxillary width, nasal cavity width and nostril width, obtained through cone beam computed tomography scans. The predictive models were built using the following machine learning algorithms: Adaboost Classifier, Decision Tree, Gradient Boosting Classifier, K-Nearest Neighbours (KNN), Logistic Regression, Multilayer Perceptron Classifier (MLP), Random Forest Classifier and Support Vector Machine (SVM). A 5-fold cross-validation approach was employed to validate each model. Metrics such as area under the curve (AUC), accuracy, recall, precision and F1 Score were calculated for each model, and ROC curves were constructed.

RESULTS

The predictive model included four variables (two dental and two skeletal measurements). The interpterygoid width and nostril width showed the largest effect sizes. The Gradient Boosting Classifier algorithm exhibited the best metrics, with AUC values ranging from 0.91 [CI95% = 0.74-0.98] for test data to 0.89 [CI95% = 0.86-0.94] for crossvalidation. The nostril width variable demonstrated the highest importance across all tested algorithms.

CONCLUSION

The use of maxillary measurements, through supervised machine learning techniques, is a promising method for predicting palatally impacted maxillary canines. Among the models evaluated, both the Gradient Boosting Classifier and the Random Forest Classifier demonstrated the best performance metrics, with accuracy and AUC values exceeding 0.8, indicating strong predictive capability.

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.

Palatal canine impaction is associated with craniofacial shape in humans

BACKGROUND/OBJECTIVES

It is unclear whether palatal canine impaction is related to genetic or local/environmental factors. If a genetic origin is assumed, then it could be expected that palatal canine impaction is associated with overall craniofacial development. Within this context, the aim of this study was to evaluate the craniofacial morphology of individuals with palatal canine impaction and compare it to a matched group of normal controls.

MATERIALS/METHODS

The sample for this investigation comprised 404 individuals (232 females and 172 males). Half of these individuals presented with unilateral or bilateral palatal canine impaction confirmed clinically and radiographically. The other half were matched for sex and age with the first half and comprised individuals without tooth impaction, apart from third molars. The shape of the craniofacial structures was outlined on calibrated cephalometric images through 15 curves and 127 landmarks (11 fixed and 116 semi-landmarks). Shape configurations were superimposed using Procrustes Superimposition and the resulting shape coordinates were reduced into principal components for all subsequent analyses. The effect of palatal canine impaction on craniofacial shape was assessed with regression models, separately in females and males. All statistical tests were performed assuming a type-1 error of 5%.

RESULTS

Individuals with palatally impacted canines appear to have a less convex face, a more brachyfacial skeletal pattern, and a sagittally extended premaxilla. In females effect sizes ranged between η2 = 0.136-0.397 (P < 0.05) and in males between η2 = 0.125-0.396 (P < 0.05, apart from the entire craniofacial configuration: P = 0.259).

LIMITATIONS

Palatal canine impaction was not confirmed through cone beam computer tomography images in all patients, however, in those cases, the treatment history confirmed the diagnosis.

CONCLUSIONS/IMPLICATIONS

Palatal canine impaction is related to a distinct craniofacial shape in females and males. These findings allow for speculation that palatal canine impaction is affected by genetic pathways involved in overall craniofacial development.

Craniofacial morphology in patients with impacted canine: a case control-study

BACKGROUND

The objective of this study was to evaluate the risk of maxillary canine impaction through cephalometric evaluation.

METHODS

One hundred and eighty-two Caucasian patients (80 males and 102 females) with a mean age of 12.4±0.5 were retrospectively enrolled in the present study. Ninety patients with impacted canines were compared with ninety-two patients with physiologically erupted canines. The following cephalometric variables were analyzed: SNA, ANB, SN-GOME, GO-ME, SP-CL, SELLA TURCICA DEPHT, A-Pt LINE, B-Pt LINE, A-Pt LINE°, B-Pt LINE°, A1s-Pt, A1i-Pt, A1s-Pt°, A1i-PT°, A-SN, B-SN and SN-U1. When applicable, a paired sample t-test was performed to investigate the difference in means between the two sample groups, while the Mann-Whitney Test was used as a non-parametric test in the case of a non-normal distribution of data. Statistical significance was set at P<0.05.

RESULTS

The group with impacted canines showed an increase in Go-Me distance, SNA angle and A1s-Pt angle compared with the control group. In addition, the same group showed a decrease in A-SN and SP-Cl distance compared with the control group.

CONCLUSIONS

An increase in mandibular length (GO-ME) and SNA angle associated with a reduction in A-Sn distance and interclinoid distance (SP-Cl) were observed in patients with impacted canines.

The Analysis of Intermolar Width and Skeletal Base Class as a Predictor of Potential Maxillary Canine Impaction in Permanent Dentition: A Cross-Sectional Study

Objectives. This study aimed to analyze the inter-molar width and skeletal base class to predict maxillary canine impaction in permanent dentition. Methods. This cross-sectional study was carried out between September 2021 to March 2022. Patients aged between 13 and 20 years were recruited. These patients' cone-beam computer tomography(CBCT), lateral cephalogram, and dental casts were collected and analyzed. For statistical analysis, T-test and Chi-square tests were applied. Results. A total of 92 patients were enrolled in this study. Inter-molar width was significantly decreased in patients with impacted canine(P < .001). The skeletal base classification was statistically significant when compare with intermolar width(P < .05). The location of impaction (P = .060), type of impaction(P = .435), and side of impaction(P = .239) were determined to be statistically insignificant. Conclusion. The Inter-molar width was decreased in patients with impacted canine; therefore, it may be a potential risk factor. The skeletal classification was found to affect inter-molar width in impacted canine patients.

Evaluation of the relationship between maxillary canine impaction with arch dimensions and maxillary sinus dimensions using Cone Beam Computed Tomography (CBCT )

Background

We aimed to evaluate the morphology of maxilla and sinus dimensions in subjects with unilaterally and bilaterally impacted canine using cone beam computed tomography (CBCT) records.

Methods

CBCT records taken during 2020-2022 of 120 patients were obtained to investigate the relationship between impacted canine and maxillary morphology as well as sinus dimensions. The CBCT images were then divided into three groups: control, unilaterally canine impaction and bilaterally canine impaction. Then morphology-related variables (arch circumference, arch length, inter molar width, inter first premolar width, palatal depth, anterior posterior dimension of the right and left sinuses, and mediolateral dimension of the right and left sinuses) were analyzed and compared between groups. All measurements were done by Ondeman 3D dental software. Statistical analysis was carried out by SPSS software version 21 using one-way ANOVA.

Results

There were meaningful differences in patients with canine impaction compared with control group in arch circumference (P value= 0.004) and arch length (P value= 0.001), inter molar width (P value= 0.001), inter first premolar width (P value= 0.001), mediolateral dimension of the right (P value=0.001) and left (P value= 0.001) sinuses of maxilla. Furthermore, Palatal depth and anterior posterior dimension of the right and left sinuses did not show statistically significant difference between groups.

Conclusion

Canine impaction can considerably affect the morphology of maxillary and sinuses dimensions. Nevertheless, future studies are needed to determine the exact structural and molecular effects of the canine impaction on maxillary sinuses and neighboring tissues.

Screening for the risk of canine impaction, what are the presumptive signs and how does it affect orthodontics? A cross-sectional study in France

PURPOSE

The treatment of impacted canines is a challenge for orthodontists. The availability of suggestive clinical signs has become crucial for treatment before the potential for evolution ceases. The main objective was to evaluate the prevalence of the suspected displaced canine (SDC) and to highlight factors easily identifiable from the oral examination.

METHODS

SDC was assessed on panoramic X-rays, on the basis of the angle with the median sagittal plane and the degree of overlap with the permanent lateral incisor. Its association with mesio-distal tooth and palate widths was assessed by univariate analysis. Next, the association of SDC with temporary tooth extraction, expansion and/or premolar extraction was considered using the same modality.

RESULTS

In this retrospective study, the records of 292 patients aged 7 to 13 years were reviewed. SDC was detected in 39% of patients i.e., 28,8% of observed canines. Reduced coronal mesio-distal diameters of permanent maxillary central incisors, 8.7 ± 0.6 mm versus 8.8 ± 0.7 mm (p < .05), and first permanent molars, 10.0 ± 0.7 mm versus 10.2 ± 0.7 mm (p < .001), as well as reduced inter-molar width, 38.7 ± 2.7 mm versus 39.4 ± 2.9 mm (p < .01), were predictive factors. SDC led orthodontists to indicate extraction of maxillary primary canines, OR = 3,32 (p < .001) or even extraction of premolars, OR = 1,66 (p < .05).

CONCLUSION

This study confirmed the interest of panoramic X-rays in detected canines at risk of SDC. Dental factors can be combined to make screening more reliable and predict impaction that makes orthodontics complex.

TRIAL REGISTRATION NUMBER

Opinion n°21.131, dated 09.21.2021, retrospectively registered.

Statistical shape analysis of maxillary palatal morphology in patients with palatally displaced canines

OBJECTIVE

Maxillary morphology has long been a subject of interest due to its possible impact on palatally and labially displaced canines. This study aims to conduct a comparison of the palate morphology between individuals with palatal and labially displaced canines and control subjects using statistical shape analysis on a coronal cross-sectional of CBCT images.

MATERIALS AND METHODS

Patients aged between 12 and 43 years with palatally or labially displaced canines referred to Hamadan School of Dentistry between 2014 and 2019 were recruited for this retrospective study. The sample included 29 palatally displaced canines (PDC), 20 labially displaced canines (LDC), and 20 control groups (CG). Initially, the maxillary palate coronal section was acquired and landmarked in the region between the right and the left first molar. Procrustes and principal component analyses were used to identify the primary patterns of palatal shape variation. Statistical tests were then performed to examine both shape and size differences.

RESULTS

According to the results of Hotelling's T2 test, there is a significant difference between the mean shape of palate in PDC and CG (P = 0.009), while the difference between the PDC-LDC and LDC-CG groups is not significant. The longest full Procrustes distance was observed between PDC and CG (distance = 0.043), and the shortest full Procrustes distance was observed between LDC and CG (distance = 0.029). The first two principal components accounted for 84.47% of the total variance. The predictive accuracy of the discriminant analysis model showed that 72.46% of cases were correctly classified into the three study groups.

CONCLUSIONS

In terms of centroid size, there was no significant difference in the sectional area between the three groups, but the difference between the mean shape of palate in the PDC and CG groups was significant. The PDC group showed more prominent mid-palatal area in the molar region.

The Relationship between Unilateral Palatal Maxillary Canine Impaction and the Morphology of the Maxilla: A CBCT Study in Eastern Province of Saudi Arabia

OBJECTIVE

 This study aimed to examine the correlation between the morphology of the maxilla and unilateral palatally impacted maxillary canine (PIMC) among the Saudi population in the Eastern Province of Saudi Arabia.

MATERIALS AND METHODS

In this retrospective study, 36 patients' records [(17 PIMC, 8 male, 9 female, mean age 16.75 ± 2.12 years) (19 control; 9 male,10 female, mean age: 17.16 ± 2.12 years)] were included from a teaching dental hospital. On cone-beam computed tomographic images, measurements of maxillary arch length (MAL), palatal vault depth (PVD), intermolar width, sum of widths of 4 maxillary incisors, available arch space (AAS), palatal maxillary width (PMW) in the molar and premolar regions, nasal cavity width (NCW), maxillary arch shape (MAS) (arch length/intermolar width x 100), and palatal vault shape (PVS) (the PVD/intermolar width x100) were performed. Data were analyzed by SPSS-20.0. p-value less than or equal to 0.05 reflected statistical significance.

RESULTS

 This study's findings depicted that AAS (p = 0.012), PVD (p = 0.028), and PMW in the molar and premolar regions at the level of the alveolar crest (p = 0.002 and p = 0.034) and mid-root (p = 0.004 and p = 0.022) were significantly higher in the control compared to the PIMC group. PVS showed a significant difference between the PIMC and control groups (p = 0.037). However, regarding MAS, no significant difference was observed (p = 0.707).

CONCLUSION

 MAS was narrower in PIMC compared to the control group. The control group had a deeper palatal vault and greater AAS compared to the PIMC group. However, no significant difference was observed between groups regarding tooth size or NCW.

Three-Dimensional Measurements of the Palate and Dental Arch Perimeter as Predictors for Maxillary Palatal Canine Impaction-A Cone-Beam Computed Tomography Image Analysis

(1) Background: Accurate diagnosis and treatment plans in orthodontics were facilitated by novel technologies. The prediction of occlusal problems is of utmost importance for clinicians. This present study aimed to find any possible correlation between unilateral and bilateral palatally impacted maxillary canine, palatal dimensions, and maxillary arch perimeter using digital measurements and determine the factors that could be used as predictors for maxillary palatal canine impaction. (2) Method: A cross-sectional study was conducted on cone-beam computed tomography images of orthodontic patients aged 15 to 25. Palatal dimensions and maxillary arch perimeter were digitally measured using Materialize Interactive Medical Image Control System. (3) Results: A significant difference was found between the case and the study groups regarding palatal depth, length, and arch perimeter, except for the palatal width. A weak correlation was reported in palatal depth and length with canine impaction, whereas the correlation was moderate concerning the arch perimeter. They can be used as predictors for palatal canine impaction. (4) Conclusion: Palatal dimensions and dental arch perimeter affect maxillary palatal canine impaction. Deficient arch perimeter, palatal depth, and length could be helpful in the prediction of maxillary palatal canine impaction.

Investigation of the relationship between maxillary dimensions and labial and palatal maxillary impacted canines using cone beam computed tomography

OBJECTIVES

To compare the maxillary dimensions of individuals with labial and palatal bilateral maxillary canine impaction and a control group of individuals with no impaction using CBCT.

METHODS

45 patients were included in the study with age range of 13 to 18 and consisted of 22 females and 23 males. The sample included three groups of 15 patients as the control, labial and palatal group. The measurements made on the axial and coronal planes were made on the levels of the 1st premolar and the 1st molar. Also nasal cavity and anteroposterior depth were measured.

RESULTS

The maxillary anteroposterior depth, basal first molar width, alveolar first molar and premolar width and first molar palatal vault depth of the control group were significantly higher than labial and palatal groups (p<0.05).The basal first premolar width of the control group was significantly higher than palatal group (p<0.05). The first premolar palatal vault depth and nasal cavity width of the palatal group were significantly lower than other groups (p<0.05).

CONCLUSIONS

The basal and alveolar widths associated with the molars and the palatal depths were lower in the impacted group than control group. The anatomical structures in the female patients were affected by the position of impaction to a higher extent in comparison to the anatomical structures in the male patients.

Maxillary dimensions and arch shape with palatally displaced canines

BACKGROUND/OBJECTIVES

The aim of this study was to explore the effect of palatally displaced canines on maxillary dimensions and arch shape.

METHODS

Occlusal and skeletal landmarks were plotted on cone beam computed tomography (CBCT) images of 156 orthodontic patients: 78 with palatally displaced canines (PDC) (27 left, 28 right, and 23 bilateral) and 78 controls using Mimics™ (Materialise, Belgium). Arch forms were created, and arch width, depth, and skeletal dimensions were measured. T-test (P < 0.05) was used to compare the groups. Geometric Morphometrics (GM) analysis was used to compare the groups and to explore the pattern of covariation between two sets of landmarks.

RESULTS

The unilateral PDC group showed an increased first premolar, second premolar, molar widths, and an increased molar depth. No significant difference was found in arch form. The skeletal measurements were generally larger in the PDC group, but the transverse measurements were the most significant. Discriminant Function Analysis (DFA) with cross-validation allowed an accurate classification of 85.9% of the control group and 66.7% of the PDC group. The Mahalanobis distance displayed significant differences among three combinations of groups. Strong covariance was found between the second premolar and all other landmarks.

LIMITATIONS

The small sample sizes of the stratified groups precluded recognition of statistical significance.

CONCLUSIONS

Patients with unilateral PDC displayed significantly wider first, second premolar, and first molar widths, and increased first molar depths. There were no significant differences in arch form; however, GM showed significant differences between the groups and a prominent covariance function for the 2nd premolars.

Qualitative and quantitative three-dimensional evaluation of maxillary basal and dentoalveolar dimensions in patients with and without maxillary impacted canines

Background

This study aimed to three-dimensionally evaluate the qualitative and quantitative maxillary basal, dentoalveolar, and dental dimensions in patients with unilateral or bilateral maxillary impacted canines relative to their normal peers.

Materials and methods

This is a retrospective comparative study. Cone-beam computed tomography images of one hundred and fifty adult patients were divided into three equal groups: unilateral, bilateral, and control groups. Each had 50 patients that were three-dimensionally analysed. The quantitative measurements involved three basal (molar basal width, premolar basal width, and arch depth), seven dentoalveolar (molar alveolar width, premolar alveolar width, inter-molar width, inter-premolar width, inter-canine width, arch length, and arch perimeter), and two dental (canine length and width) measurements. The qualitative measurements included four bone density areas (buccal, lingual, mesial, and distal) around the maxillary impacted canines.

Result

Differences between the three groups were statistically different for the quantitative measurements involving the two basal variables (molar basal width and premolar basal width) and all measured dentoalveolar variables; these were smaller in the unilateral and bilateral groups compared with the control group (p < 0.001). Unilateral and bilateral impacted canine groups showed significantly wider and shorter canines than the control group (p < 0.001). The qualitative measurements (the four bone density areas) around unilateral and bilateral impacted canine groups showed significantly greater density than the control group (p < 0.001). There was no significant qualitative or quantitative difference between the unilateral and bilateral impacted canines. The three groups had no significant variations in terms of arch depth.

Conclusion

Maxillary unilateral and bilateral canine impactions are associated with reduced basal and dentoalveolar dimensions as well as wider and shorter maxillary canines compared to normal peers. The quality of bone around unilateral and bilateral impacted maxillary canines is higher than in non-impacted cases. Unilateral and bilateral canine impactions have quite similar qualitative and quantitative parameters.

Evaluation of maxillary arch width and palatal volume and depth in patients with maxillary impacted canine by CBCT

Introduction

Canines are the second most common tooth in terms of impaction. Impacted teeth can be associated with some different indices of dental arch and dentoalveolar structures. The aim of this study was to evaluate maxillary arch width as well as volume and depth of palate in patients with maxillary impacted canine by cone beam computed tomography (CBCT).

Methods

In this cross-sectional study, 45 CBCT images of patients with unilateral maxillary impacted canines were examined. All patients had palatally impacted canines. Three parameters of maxillary arch width, palatal volume and palatal depth were assessed using axial and sagittal incisions on the CBCT images. Then all the measurements on the impacted side were compared with the non-impacted side. Data were entered into SPSS software and paired sample t-test and Student's t-test were used to comparison. The significance level of 0.05 was considered.

Results

The maxillary arch width on the impacted side was significantly less than the normal side (P < 0.001). The mean depth of the palate was 14.86 ± 3.53 mm. There was a significant correlation between canine impaction and Palatal volume (R = 0.728 and P-value< 0.001), but no significant correlation between canine impaction and Maxillary arch width was shown (R = 0.15 and p-value = 0.326).

Conclusion

The impacted canine was significantly associated with a reduction in the width of the maxillary arch on the affected side, and it made no difference if the impacted side was left or right. Also, impacted canine teeth were significantly associated with volume reduction on the affected side.

Comparison between Digital Casts and Cone Beam Computed Tomography for Measuring Maxillary Transverse Dimensions in Patients with Impacted Canines

Cone beam computed tomography (CBTCT) scans (n = 45) and digital dental casts (n = 45) were both used to measure the maxillary transverse dimensions in patients with impacted maxillary canines. The objectives were to explore the associations of these dimensions with the impaction and patient characteristics, and to compare the measurements between these techniques. The maxillary width was measured on scans and casts at the Walaridge, and the intermolar width and interpremolar width levels were measured at the first and second premolars (measured from the buccal grooves and the palatal cuspids, and the palatal and lingual amelocemental junctions). Two examiners independently compared the measurements between the control quadrants (without impaction) and the case quadrants (with impaction) in patients with unilateral impactions, and between the unilateral and bilateral impaction groups. The interclass correlation coefficient (ICC) was calculated to assess the interexaminer reliability and paired or independent Student’s t-tests and ANOVAs were used for comparisons. The ICCs were 0.887 and 0.919, globally, for the measurements on the CBCT scans and casts, respectively, which indicates the excellent interexaminer reliability. On the CBCT scans, statistically significant differences were found between the case and control quadrants in the transverse measurements at the lingual level on the upper first molars, and at the WALA ridge level on the upper second premolars (p < 0.05) in the unilateral impaction group. Significant differences were found between the case quadrants in the unilateral versus the bilateral groups at the WALA ridge on the second premolars in casts (p < 0.05), and at the lingual point on the first molars on the CBCT scans (p < 0.05). No statistically significant differences in the transverse measurements were observed between the impacted buccal and palatal canines on either the casts or CBCT scans. To the best of our knowledge, this is the first study to compare the transverse measurements between digital models and CBCT scans.

Development of difficulty index for management of impacted maxillary canine: A CBCT-based study

BACKGROUND

The aim of this study was to propose an Impacted Canine Treatment Difficulty Index using Cone-beam Computed Tomography (CBCT) imaging to assess difficulty anticipated during the alignment of impacted maxillary canine and further validate the index in clinical set up.

METHODS

Pre-treatment CBCT of 15 patients with unilateral or bilateral impacted maxillary canine aged between 12 and 30 years were selected. All the following five factors were assessed on CBCT image: 1) angulation, 2) vertical position, 3) bucco-palatal position, 4) horizontal position and 5) rotation. Two orthodontists evaluated the pre-treatment CBCT for the selected five factors and allocated a total difficulty score. To validate the proposed difficulty index in clinical settings, a team of oral and maxillofacial surgeons were included in the study to grade the difficulty encountered during surgical procedure.

RESULTS

The distribution of difficulty score recorded by observer 1 was significantly associated with the difficulty score recorded by observer 2 (P-value < 0.001), with relatively higher level of linearly weighted Cohen's kappa value of 0.610. The distribution of difficulty score recorded by oral and maxillofacial surgeon was significantly associated with the difficulty score recorded by observer 1 (P-value < 0.01), with relatively higher level of linearly weighted Cohen's kappa value of 0.667. The distribution of difficulty score recorded by orthodontist was significantly associated with the difficulty score recorded by observer 1 (P-value < 0.001), with relatively higher linearly weighted Cohen's kappa value of 0.819.

CONCLUSION

Impacted Canine Treatment Difficulty Index using CBCT imaging could be used to assess the difficulty that would be anticipated during the alignment of impacted maxillary cuspid.

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.

The effect of extraction of lower primary canines on the morphology of dental arch: A systematic review and meta-analysis

BACKGROUND

The beneficial effect of the extraction of primary canines in the resolution of incisor irregularity and its side effects are controversial.

AIM

To systematically review the effects of the extraction of primary canines in incisor irregularity and dental arch morphology.

DESIGN

Controlled non-randomized (non-RCT) and randomized clinical trials (RCT) evaluating children treated with extraction of primary canines compared with those without intervention.

RESULTS

A total of 984 articles were found, of which two RCTs and one non-RCT met the inclusion criteria. Both had a low RoB. A high level of evidence was observed through GRADE. A meta-analysis showed the extraction of primary canines produced a significant decrease in incisor irregularity (95% CI: -3.56, -2.09 mm). This decrease, however, was associated with a reduction of arch length (95% CI: -1.58, -0.94 mm), intermolar width (95% CI: -0.61, -0.22 mm), and overjet (95% CI: -075, -018). A mild overbite increase was found (95% CI: 0.10, 0.76 mm).

CONCLUSION

A high level of evidence showed that the extraction of primary canines improved incisor irregularity in the mixed dentition. Side effects included reduced arch length and intermolar width. A slight reduction in overjet and a mild increase in overbite were also observed. When they are not part of the treatment goal, these occlusal changes can be prevented by installing a lingual arch.

Association between maxillary transverse discrepancy and occurrence of potentially impacted maxillary canines in mixed dentition patients

OBJECTIVE

The aim of this study was to determine the association between transverse maxillary discrepancy and occurrence of potentially impacted maxillary canines in mixed dentition patients.

MATERIAL AND METHODS

This cross-sectional analytical study was conducted on 85 Pakistani subjects (32 males and 53 females) aged between 8 to 13 years, having good quality orthopantomographs and dental casts. Maxillary transverse discrepancy was assessed by subtracting the mandibular intermolar width from the maxillary intermolar width on dental cast. Maxillary lateral incisors and canines were traced from orthopantomographs, and canines were placed into sector classification. Chi-square test was used to determine the difference in the occurrence of potentially impacted maxillary canines between patients with maxillary transverse discrepancy and patients without maxillary transverse discrepancy.

RESULTS

There was no significant difference seen in the occurrence of impacted maxillary canines in patients with and without maxillary transverse discrepancy in mixed dentition patients.

CONCLUSION

Patients with maxillary transverse discrepancy may not be at a higher risk of palatal canine impaction. Radiological presence of canine in sector II, III and IV, pose a higher risk of canine impaction.