Development and validation of a new prognostic tool for impacted maxillary canines, 'Easy box': A cone-beam computed tomographic study.

OBJECTIVE: To develop a tool to facilitate simple, easy and rapid assessment of the level of difficulty in disimpaction of an impacted canine using cone-beam computed tomography (CBCT). DESIGN: A cross-sectional study. METHODS: A panel of four experienced orthodontists formulated a questionnaire capable of portraying the limits of a three-dimensional (3D) area around impacted maxillary canines on CBCT images, which would determine the disimpaction difficulty level. In total, 14 experienced orthodontists graded each item in the questionnaire and assigned scores in the range of 0-5. Average scores obtained outlined the limits of a 3D area, within which an impaction was deemed favourable. This area was termed 'Easy box'. The disimpaction difficulty level of 170 impacted maxillary canines was then assessed using 'Easy box' and the existing tool KPG index for convergent validation. RESULTS: Perfect inter-examiner agreement was obtained as evidenced by Fleiss kappa value of 0.984 for the tool 'Easy box' and 0.948 for the KPG index. There was also perfect agreement between the two methods of assessment (Cohen weighted kappa, k>0.86). The average time taken for assessment using 'Easy box' was 3.3 min compared to 8.8 min for the KPG index. CONCLUSION: 'Easy box' proves to be a simple, accurate and rapid assessment tool for the prognostic evaluation of impacted canines, using CBCT images. Impacted maxillary canines with cusp tips that lie beyond the limits of the 3D 'Easy box' area with a beta angle greater than 45°, were rated to be more difficult to align.

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.

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.

Associations among the occurrence or types of maxillary canine impaction, labial frenum attachment types, lateral incisor anomalies, and midline diastema in patients with and without impaction: A case-control study.

INTRODUCTION: We tested whether the labial frenum attachment types may affect the occurrence or type of maxillary canine impaction. METHODS: This case-control study was performed on 96 subjects (48 with maxillary canine impaction [20.50±4.99 years, 32 females], 48 controls [21.94±3.79, 31 females]). Types of canine impaction (buccal/palatal, bilateral/unilateral, left/right), types of upper lip middle frenums (mucosal, gingival, papillary), the anatomy of lateral incisors (impacted, peg shaped, small, normal), and the midline diastema were evaluated clinically and radiographically. Associations were examined using multiple binary logistic regression, 3-way repeated-measures ANCOVA, and Fisher tests (α=0.05, ß=0.2). RESULTS: The numbers of mucosal, gingival, and papillary frenums in the case group were '29, 14, and 5', respectively; in the control group, they were '25, 21, and 2' (Fisher, P=0.248). The numbers of mucosal, gingival, and papillary frenums were respectively '25, 11, and 1' in the palatally impacted canine subgroup; they were '4, 3, and 4' in the buccally impacted subgroup (Fisher, P=0.010). Abnormal laterals were present in 12 cases and 4 controls; normal laterals were observed in 36 cases and 44 controls (Fisher, P=0.053). Abnormal laterals were seen in 10 cases with palatally impacted canines and 2 cases with buccally impacted canines; normal laterals existed in 27 cases with palatally impacted canines and 9 cases with buccally impacted canines (Fisher, P=0.705). Lateral anatomy was not associated with frenum attachment (Fisher, P=0.827). Greater midline diastemas were seen in cases with maxillary canine impaction, papillary frenums, and abnormal laterals (ANCOVA, P≤0.016). CONCLUSIONS: Buccal type of canine impaction is positively associated with papillary labial frenums. Canine impaction is 3.6 folds more prevalent in cases with lateral abnormality. Midline diastema is positively and independently associated with canine impaction, papillary frenums, and abnormal laterals.

Normal pre-eruptive inclinations of maxillary canine, lateral incisor, and first premolar in children aged 6-14 years.

BACKGROUND: Maxillary canine is the second most common tooth that gets impacted after III molars. Early pre-eruptive inclination changes of first premolar and its associative changes with canine inclination are an important factor that predicts the fate of maxillary canines. Hence, a cross-sectional study was planned to evaluate the normal pre-eruptive mesiodistal inclinations of maxillary permanent canine, first premolar, and lateral incisor in children aged 6-14 years using orthopantomogram. MATERIALS AND METHODS: The total number of participants was 296. Each group of boys and girls consisted of 37 participants in each of the age groups 6-8 years, 8-10 years, 10-12 years, and 13-14 years, making up a total of 148 boys and 148 girls. Routine clinical examination was conducted, and orthopantomograph was taken for radiographic examination. Orthopantomographs of all these participants were collected. Inclination of lateral incisor, inclination of canine, and inclination of premolar with midline were measured on the orthopantomogram. Also, the angles between the canine with lateral incisor and canine with first premolar were measured. Pearson correlation was also evaluated between the movement of canine with lateral incisor and canine with first premolar. RESULTS: All the mean angles related to lateral incisor, canine, and first premolar with midline were recorded. Also, the angles between the canine with lateral incisor and the canine with first premolar were recorded. The movements between lateral incisor, canine, and first premolar were moderately correlated from 6 to 12 years of age. CONCLUSION: The eruption of canine from the floor of the nose till it erupts has its synchronized influence on the lateral incisor and the first premolar.

Treatment for critically impacted maxillary canines: Clinical versus scientific evidence - A systematic review.

BACKGROUND: Critically impacted maxillary canines are prone to fail to respond to conventional surgical exposure and orthodontic traction. Correct identification of a critical impaction requires enhanced diagnosis modalities and might lead to incorporating alternative surgical strategies in the treatment plan. Predictability of techniques such as apicotomy or tooth autotransplantation is, however, yet to be determined. The objective of this study was to systematically review treatment perspectives for critically impacted maxillary canines. METHODS: A systematic review of the available literature until april 2020 was conducted using an electronic search in Embase, Cochrane Central, Web of Science and PubMed databases. Randomised and non-randomised studies investigating treatment options and treatment outcome for buccally and/or palatally critically impacted maxillary canines were considered for the review. Information recorded concerned study design and setting, participants' characteristics and details regarding the type of intervention, types of outcomes measured and follow-up time. The included studies received a methodological quality scoring and risk of bias analysis according to a tool suggested by Murad et al (2018). RESULTS: Five studies were included in the quality analysis, all case series. The included studies enrolled a total of 302 patients and counted 346 critical maxillary canine impactions. Apicotomy and autotransplantation were listed as potential surgical approaches with surgical outcome presented for both surgical strategies. Adequate esthetical and/or functional outcomes were reported in most of the included studies. According to the quality assessment tool used, the reviewed studies scored medium on the proposed scale. DISCUSSION: Literature featuring protocols for identifying and treating critical maxillary canine impaction only consists of case series and case reports, which provide low level of evidence. The rather good results reported by the reviewed studies must be put into perspective as the methodology of these studies was insufficient and potential bias was identified. Comprehensive clinical research is needed to further investigate treatment options and form a basis for clinical guidelines.

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.

Radiographic assessment of the prevalence, pattern and position of maxillary canine impaction in Najran (Saudi Arabia) population using orthopantomograms - A cross-sectional, retrospective study.

OBJECTIVE: The objective of this study is to assess the prevalence and pattern of maxillary canine impaction (MCI) in the population of Saudi Arabia according to the Yamamoto classification. MATERIALS AND METHODS: A total of 5000 orthopantomogram (OPG) images of 2500 males and 2500 females in the age group of 14-40 years who attended the orthodontic clinic in Najran city from a period between January 2016 to February 2019 were evaluated for the presence of maxillary canine impaction. The anatomical position of each maxillary canine impaction was matched to the seven subtypes mentioned in the Yamamoto's classification. RESULTS: The prevalence of MCI was found to be 3.46% in Najran(Saudi Arabia) population. Type I (46%) accounted for the highest prevalence followed by Type II (37%) and Type VI (8%). Type III, V and VII was found to be 3% equally and no case was of Type IV was found in the studied population. MCI was more common in females and left side compared to males and right side respectively. CONCLUSION: The prevalence of maxillary canine impaction was found to be 3.46% in Najran. Type I pattern of maxillary canine impaction was commonest followed by Type II, VI, III, V and VII.

Morphological relationship analysis of impacted maxillary canines and the adjacent teeth on 3-dimensional reconstructed CT images.

OBJECTIVE: To examine whether there is a relationship between maxillary canine impaction and the morphologic characteristics of the maxillary dentition, especially the root of the lateral incisor. MATERIALS AND METHODS: In this study, we selected only patients with unilateral maxillary canine impaction to compare the morphologic characteristics of the dentition on the impaction side and the clinically normal eruption side. The sample size was decided to be 40 based on the pilot study. To minimize bias depending on sex and location of the maxillary canine impaction, we selected equal numbers (20) of boys and girls, and equal cases (20) of buccal impaction and palatal impaction. Under the aforementioned conditions, the mean age was 13.5 ± 2.3 years. The multislice spiral computed tomography images of these 40 subjects were converted into three-dimensional (3D) reconstructed images using the OnDemand 3D program (Cybermed Co, Seoul, Korea). Then we measured the morphologic characteristics of the individual teeth on the obtained 3D teeth images. RESULTS: Length and volume of the maxillary lateral incisor's roots were significantly smaller on the impaction side compared with the normal eruption side (P = 0.001 and P = 0.006, respectively). The width and volume of the canine's crown were significantly greater on the impaction side compared with the normal eruption side (P = 0.020 and P < .0001, respectively). CONCLUSION: These results might help to prove the hypothesis that the smaller-sized lateral incisor roots and greater-sized canine crowns are the influential etiologic factors in maxillary canine impaction.