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

Comparison of the mesiodistal angulation of maxillary canines based on their impaction sector in panoramic radiographs: A cross-sectional study

INTRODUCTION

The complexity of treating impacted maxillary canines varies based on their angulation and position within the dental arch. The aim of this research was to compare the mesiodistal angulation of maxillary canines according to their impaction sector.

METHODS

This cross-sectional study evaluated 229 impacted maxillary canines in 171 panoramic radiographs from two private radiology centres in Uruguay and Chile of individuals of both sexes aged 11 years and older with impacted maxillary canines. The radiographs were taken with two panoramic radiography equipment. All the images were evaluated using Planmeca Romexis® software. Two investigators were trained and calibrated to perform all the measurements at two measurement times. The Ericson and Kurol method was used to classify the impaction sector into five sectors and the Wardorf method was used to measure the mesiodistal impaction angle and, finally, the level of impaction was measured with respect to the root of the lateral incisor. Student t-test, Anova and multiple linear regression were used. P<0.05.

RESULTS

The impaction angle of sectors 1 and 2 was (70.03°±9.65°) and of sectors 3, 4 and 5 it was 52.21°±16.60° (P<0.001) while at the cervical level of the lateral incisor root it was 74.15°, 68.04° at mid-level and 57.39° at the apical level (P<0.001). The impaction angle decreases 13.02° in sectors 3, 4 and 5 (P<0.001), for each year the impaction angle decreases 0.30° (P=0.001), and as the level of impaction becomes more apical the impaction angle decreases 7.46°.

CONCLUSIONS

Impacted maxillary canines are more horizontal the closer they are to the midline or the higher the level of impaction. Likewise, this horizontality tends to increase over time. All these considerations should be taken into account by orthodontists when planning their treatments.

Factors influencing treatment duration of impacted maxillary canines

OBJECTIVES

To determine factors associated with treatment duration in impacted maxillary canines (IMCs) using orthopantomography and cone beam computed tomography.

MATERIALS AND METHODS

Seventeen linear and angular measurements were evaluated using pretreatment radiographic images of 64 patients (83 IMCs). Treatment duration from surgical exposure until the canine appeared in the oral cavity and until achieving ideal alignment were recorded in months.

RESULTS

Average treatment duration until appearance in the mouth was 14.61 ± 9.28 months and 26.98 ± 12.44 months until ideal alignment. Buccally impacted canines emerged in 6.56 ± 3.24 months and were ideally aligned in 19.44 ± 8.49 months in comparison with palatally positioned at 16.34 ± 9.19 and 28.91 ± 12.77 months, respectively. Canines localized around lateral incisors had shorter treatment times than those localized around central incisors. Canines that were inclined >30° to the sagittal medial line (SML) had significantly longer treatment time until initial appearance in the mouth (16.31 ± 9.32) compared with those inclined less (10.82 ± 8.92). Linear regression analyses demonstrated that these factors were predictors for both treatment duration until emergence and ideal alignment of the canine.

CONCLUSIONS

Treatment duration for IMCs is lengthy, particularly for palatally and mesially positioned canines and those with greater inclinations. Palatally located canines typically require twice as much time to emerge as those positioned buccally. Canines located nearer the central incisor area take twice as much time to emerge as those located in the lateral incisor area.

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.

A Comparison of Different Biomechanical Systems for the Orthodontic Treatment of Palatally Impacted Canines

Canine impaction constitutes a clinical entity that, if untreated, can compromise dentition. Thus, various treatment approaches and different biomechanical systems have been proposed over the years for its management. Clinical records of patients who consecutively visited the Postgraduate Clinic of the Department of Orthodontics of the Aristotle University of Thessaloniki, Greece, were retrieved and analyzed retrospectively with the aim to compare two different biomechanical systems for the orthodontic/surgical treatment of palatally displaced canines. A total of 29 patients with 36 palatally impacted canines were included in the current investigation. The patients had a median age of 16 years (IQR: 15-20); 69% of them were females (n = 20) and 31% were male (n = 9). No statistically significant differences regarding treatment outcomes were detected between different types of active unit (p > 0.99), or the types of bonded attachments (p = 0.52). The use of ballista springs or cantilever configurations was not found to significantly affect the alignment duration (p = 0.56) as opposed to the type of attachment, where eyelets outmatch brackets (p = 0.009). The use of brackets over eyelets significantly prolongs the canine alignment duration.

Prediction of the success of orthodontic treatment of impacted maxillary canines using panoramic radiography parameters: a retrospective cross-sectional study

BACKGROUND

This retrospective study aimed to investigate the relationships between the radiographic features of impacted maxillary canines (IMCs) and traction duration and the factors affecting treatment success.

METHODS

Pre-treatment panoramic radiographs and patient records of 121 consecutive patients with IMCs were analyzed. The measurements included the angle of the IMC with the midline (α-angle), the horizontal position of the IMC relative to the adjacent teeth (S-Sector), the distance from the IMC to the occlusal plane (d-distance), the apex position of the IMC (A), and the vertical height of the IMC relative to the adjacent lateral tooth (V). The measurements were repeated 1 week later. The intraclass correlation coefficient was used to evaluate the relationship between two measurements. Binary logistic regression was performed to determine the factors affecting treatment success. Linear regression was conducted to determine the relationships between traction duration and other parameters. Receiver operating characteristic (ROC) curve analysis was performed to determine the α-angle and the d-distance cutoff values for treatment success. The significance level was set at p < 0.05.

RESULTS

The buccally IMCs were mostly located in sectors 1-2, whereas the palatally IMCs were mostly located in sectors 3-4-5. The effects of the parameters on the treatment success were significant according to the logistic regression of age (p = 0.003), d-distance (p = 0.002), and α-angle (p = 0.001). Linear regression analysis revealed that traction duration was statistically significant (p < 0.001).

CONCLUSION

According to the results of this retrospective study, the α-angle, d-distance, and sector can be used to predict the buccopalatal position of the IMC. The patient's age, d-distance, and α-angle affected the treatment success. The patient's age, d-distance, and the sector of the impacted canine affected the traction duration.

CLINICAL TRIAL NUMBER

Not applicable.

Periodontal and orthodontic management of impacted canines

The maxillary and mandibular canines are described by many clinicians as the "cornerstone" of the arch. When in their optimal position, they play a critical role in providing a well-balanced occlusal scheme that contributes toward functional as well as neuromuscular stability, harmony, esthetics, and dentofacial balance. When an aberration is noted with the normal eruptive and development process, early diagnosis with strategic intervention is critical and may often require a multidisciplinary approach. A proper diagnosis, risk assessment, and management of the soft tissues, hard tissues, and adjacent structures are vital for a successful outcome. This review highlights the diagnostic and treatment modalities that require consideration for the orthodontic as well as the periodontal management of impacted canines. The reader is guided through the etiology, diagnosis, prevention, and intervention of clinical cases that were managed with different approaches.

Maxillary impacted canine replacing a central incisor with root resorption: Multidisciplinary treatment in a preadolescent patient

Maxillary canines are often impacted, which can result in tooth disorders and adversely affect occlusal and facial development. The case report describes complete bilateral impaction of maxillary canines and significant root resorption of a central incisor. The multidisciplinary approach is the optimal strategy for addressing impacted maxillary canines.

Prevalence of canine impaction in different cities of Saudi Arabia: A systematic review

Background

To our knowledge, no systematic review assessed and gathered information about the prevalence of impacted canines among the Saudi population. The purpose of this study was to critically assess the previously published studies about the prevalence of canine impaction according to impaction type (buccal/ palatal), gender (male/female), and location (maxillary/mandibular, right/left), are among the Saudi population.

Methods

PubMed (MEDLINE), Scopus, the Web of Science, Dimensions, and Semantic Scholar databases were searched systemically for articles related to the topic of the study published between 1987 and 2022. The PRISMA statements were used to conduct a systematic review with the help of the Best Practice for Survey and the Public Opinion Research scales by the American Association for Public Opinion Research (AAPOR) to assess and evaluate the selected studies' quality.

Results

The initial search of the databases yielded 221 articles. After discarding duplicates, 161 were selected for further evaluation. Eventually, 16 articles were selected for inclusion in this study. Regarding the quality of the selected articles, all articles, except one, were of high quality. Only one was of medium quality.

Conclusion

It was found that the incidence of palatal canine impactions was higher than buccal impactions. Females had a higher prevalence of canine impactions as compared to males. There were more canine impactions in the maxilla than the mandible and more on the left side than the right one.

Survival of retained permanent canines after autotransplantation: A retrospective cohort study

INTRODUCTION

After third molars, canines are the teeth most commonly affected by displacement and impaction. Although orthodontic surgical treatment represents the standard method for realignment of canines, autotransplantation (autoTX) functions as the second-line therapy if orthodontic alignment does not succeed in treating impaction and severe displacement. This retrospective cohort study aimed to identify clinical predictors for postoperative survival and endodontic treatment needs after autoTX of severely displaced and impacted canines.

METHODS

The study cohort comprised patients who received canine autoTX in a single surgical center between 2006 and 2018. Canines with severe displacement and retention were surgically treated using a standardized protocol. Statistical analysis of survival probability was performed with the Kaplan-Meier method, and bivariate data were analyzed using logistic regression and the Pearson chi-square test. Nonparametric continuous variables were analyzed using the Mann-Whitney U test.

RESULTS

Data from 319 patients with 378 canine grafts were available for analysis after a mean follow-up of 54.7 ± 36.5 months on the patient level (range, 0.3-181.8 months). With 25 lost autotransplants, the cumulative survival rate was 93.4%. Patient age at surgery, the state of the apical foramen, endodontic treatment need, and persistence of deciduous teeth at the implantation site had a significant negative impact on autotransplant survival (P <0.05). Endodontic treatment need was significantly related to the patient's age at surgery, the state of the apical foramen, and preoperative orthodontic traction (P <0.05). Thus, these independent variables were identified as clinical predictors for the survival of both the autotransplant and the dental pulp. Gender, ischemia time, postoperative ankylosis, or site of autoTX did not influence any of the outcome variables.

CONCLUSIONS

The high survival rates of autotransplanted permanent canines make this treatment a promising option, especially in patients with severe tooth displacement, in which orthodontic treatment alone cannot provide predictable alignment, irrespective of the patient's age. Interpreting age and preoperative orthodontic traction as delaying the onset of autoTX and state of apex, time-dependent aspects seem to be of great importance for postoperative complications leading to endodontic treatment or graft loss. Therefore, early implementation of autoTX as a treatment modality for impacted, severely displaced, and vain exposed canines in daily surgical practice should be encouraged.

Predictors of complications associated with unerupted maxillary canines: a cone beam computed tomography study

To detect predictive factors for the occurrence of complications associated with unerupted maxillary canines (C). A total of 83 cone beam computed tomograms (CBCT), made from November 1, 2021 to October 31, 2022, have met the inclusion criteria, whereby 110 unerupted C were detected. Independent variables were: gender, age, and C position. Outcome variables were detected complications: external root resorption (ERR) and dilaceration of adjacent tooth, ERR and dilaceration of C, dentigerous cyst, canine ankylosis, and adjacent teeth malposition. Chi-square test and logistic regression analysis were used to examine the relationship between income variables and detected complications. Vertical position of unerupted C showed as predictor for adjacent tooth dilacerations and malposition. Chance for dilaceration increases 5.5-fold with C position at the middle third of lateral incisor (LI) root, while chance of malposition increases 23.4-fold with its supra-apical position to the LI root, in comparison to the C position occlusal to the LI cemento-enamel junction. Age is a predictive factor for dentigerous cysts, with decreasing the chance of their occurrence 1.5-fold with each additional year of age. Early evaluation of the vertical position and timely treatment of C are decisive steps in preventing complications.

Preformed Elastodontic Appliances: Awareness and Attitude of Orthodontists and General Dental Practitioners

BACKGROUND

Preformed elastodontic appliances (EAs) have been described as safe, cost-effective, and easy-to-use devices for interceptive orthodontic treatment in growing patients. This study aimed to assess the knowledge and the attitude of dentists toward the use of EAs and to compare the behaviors of orthodontists (Os) with those of general dental practitioners (GDPs).

METHODS

An anonymous survey was distributed among dentists through social media. Twenty-two items were divided as follows: characteristics of respondents; general knowledge about EAs; section for EA-users; and section for EA non-users. Chi-squared tests were used to analyze differences in responses between groups.

RESULTS

Participants included 226 Os and 168 GDPs. The majority in both groups reported having adequate knowledge about EAs and utilizing them in their practice. GDPs usually use EAs to treat children during the early phase of growth, while Os also use EAs to address orthodontic problems in different stages of dentition, experiencing a chair time reduction compared with traditional appliances. Regarding EA non-users, GDPs seem not to find an application among their patients, whereas Os reported not having enough patient compliance during treatment.

CONCLUSIONS

Although treatment with EAs is common among all dentists, differences exist between Os and GDPs in the awareness and application, as well as in the reasons provided for not using EAs.

The use of CBCT in orthodontics with special focus on upper airway analysis in patients with sleep-disordered breathing

Applications of cone-beam CT (CBCT) in orthodontics have been increasingly discussed and evaluated in science and practice over the last two decades. The present work provides a comprehensive summary of current consolidated practice guidelines, cutting-edge innovative applications, and future outlooks about potential use of CBCT in orthodontics with a special focus on upper airway analysis in patients with sleep-disordered breathing. The present scoping review reveals that clinical applications of CBCT in orthodontics are broadly supported by evidence for the diagnosis of dental anomalies, temporomandibular joint disorders, and craniofacial malformations. On the other hand, CBCT imaging for upper airway analysis-including soft tissue diagnosis and airway morphology-needs further validation in order to provide better understanding regarding which diagnostic questions it can be expected to answer. Internationally recognized guidelines for CBCT use in orthodontics are existent, and similar ones should be developed to provide clear indications about the appropriate use of CBCT for upper airway assessment, including a list of specific clinical questions justifying its prescription.

Forced eruption in impacted teeth: analysis of failed cases and outcome of re-operation

BACKGROUND

Forced eruption of an impacted tooth usually requires surgical and orthodontic interventions to successfully bring the tooth into the dental arch. The clinical time required for a forced eruption is difficult to predict before treatment begins and success rates are affected by several factors before and after an eruption. This study was conducted to identify factors that affect the success of forced eruption, the duration of orthodontic treatment of impacted teeth, and the reasons for re-operation and forced eruption failure in a various teeth and cases.

METHODS

In this retrospective study, the records regarding the forced eruption of 468 teeth in 371 patients from June 2006 to May 2020 at the Advanced General Dentistry Department of Yonsei University Dental Hospital were initially examined. The records of 214 teeth in 178 patients who completed orthodontic treatment were included in the analysis. Data on patient demographics, tooth characteristics, orthodontic treatment duration, re-operations, and failures were collected from electronic medical records.

RESULTS

There was a significant difference in age between the success and failure forced eruption. Factors significantly affecting treatment duration were apex formation, position, rotation, and re-operation. Re-operation had a 96% success rate. The average orthodontic treatment duration was 29.99 ± 16.93 months, but the average orthodontic treatment duration for teeth that undergone re-operation was 20.36 ± 11.05 months, which was approximately 9 months shorter. Additionally, there was an interaction effect between rotation and re-operation on the duration of orthodontic treatment. The causes for failure of forced eruption in 6 cases were ankyloses (3 cases), incomplete alignment with the normal dental arch (2 cases), and a significant deviation in the impacted tooth's location (1 case).

CONCLUSIONS

To increase the success rate of forced eruption, age should be considered as a priority, and in order to predict the treatment period, the apex formation status, position in the arch, and rotation should be considered in addition to age. When determining re-operation, considering factors such as ankylosis, root curvature, and apex formation can help in the success of orthodontic treatment.

Deep learning driven segmentation of maxillary impacted canine on cone beam computed tomography images

The process of creating virtual models of dentomaxillofacial structures through three-dimensional segmentation is a crucial component of most digital dental workflows. This process is typically performed using manual or semi-automated approaches, which can be time-consuming and subject to observer bias. The aim of this study was to train and assess the performance of a convolutional neural network (CNN)-based online cloud platform for automated segmentation of maxillary impacted canine on CBCT image. A total of 100 CBCT images with maxillary canine impactions were randomly allocated into two groups: a training set (n = 50) and a testing set (n = 50). The training set was used to train the CNN model and the testing set was employed to evaluate the model performance. Both tasks were performed on an online cloud-based platform, 'Virtual patient creator' (Relu, Leuven, Belgium). The performance was assessed using voxel- and surface-based comparison between automated and semi-automated ground truth segmentations. In addition, the time required for segmentation was also calculated. The automated tool showed high performance for segmenting impacted canines with a dice similarity coefficient of 0.99 ± 0.02. Moreover, it was 24 times faster than semi-automated approach. The proposed CNN model achieved fast, consistent, and precise segmentation of maxillary impacted canines.

Diagnostic accuracy of conventional orthodontic radiographic modalities and cone-beam computed tomography for localization of impacted maxillary canine teeth

BACKGROUND

Orthodontic treatment planning for an impacted canine tooth requires accurate information about its position. The aim of this study was to compare the diagnostic accuracy of two conventional orthodontic radiographic modalities with cone-beam computed tomography (CBCT) for localization of impacted maxillary canine teeth.

MATERIALS AND METHODS

Panoramic radiographs, lateral cephalograms, and CBCT scans of 30 patients with unilaterally impacted maxillary canine teeth were retrieved from the archives. Eight expert orthodontists evaluated the parameters related to the location of impacted canine teeth by using panoramic radiographs and lateral cephalograms of patients. After 4 weeks, the same parameters were evaluated on CBCT scans of patients. The diagnostic accuracy of conventional modalities and CBCT was compared with each other and also with the gold standard.

RESULTS

The conventional radiographic modalities and CBCT had similar accuracy for assessment of the overall inclination (p = 0.11), apex morphology (p = 0.18), and mesiodistal position of the apex (p = 0.12). CBCT had significantly higher accuracy for determination of incisal tip location (p = 0.001), labiopalatal (p = 0.001) and vertical (p = 0.01) position of the crown tip, minimum bone thickness covering the crown (p = 0.001), and root resorption of the adjacent tooth (p = 0.001).

CONCLUSION

The combination of panoramic radiographs and lateral cephalograms was sufficiently accurate to assess some diagnostic parameters such as overall inclination, apex morphology, and mesiodistal apex location of impacted canine teeth.

Three-dimensional decision support system for treatment of canine impaction

INTRODUCTION

This study aimed to develop a 3-dimensional (3D) characterization of the severity of maxillary impacted canines and to test the clinical performance of this characterization as a treatment decision support tool.

METHODS

Cone-beam computed tomography images obtained from 83 patients with 120 impacted maxillary canines were included. Quantitative information on the canine 3D position and qualitative assessment of root damage of adjacent teeth were evaluated. A severity index was constructed on the basis of the quantitative findings. Clinical applicability was tested by comparing clinical diagnosis and treatment planning for conventional records vs the 3D characterization via a 2-part survey.

RESULTS

The average quantitative assessments of impacted maxillary canine position were 6.4 ± 3.6 mm from the midsagittal plane, 11.6 ± 3.1 mm in height relative to the occlusal plane, 31.5° ± 18° of roll, and 48.8° ± 14.3° of pitch. The severity index ranged from 0-13 with a mean score of 4.5 ± 2.2. Overlap with adjacent teeth was the greatest contributor (33%) to the index. Bicortically impacted canines caused the most severe root damage. Cone-beam computed tomography was preferred for assessing root damage and overall severity, whereas conventional imaging was sufficient for height and angulation assessment. The 3D report was very important or important for evaluating root damage, canine position, overall severity, and overlap. The 3D report changed most of the decisions relating to biomechanics, patient education, and treatment time estimate. The decision of exposure and traction vs extraction was changed 22% of the time after the presentation of the 3D report.

CONCLUSIONS

The overlap with adjacent teeth frequently contributes the most to the severity index. The 3D report provided relevant clinical information regarding the canine position, damage to adjacent teeth, and the severity index, with a profound impact on the decisions of the clinicians regarding biomechanics, patient education, and treatment time estimate.

Maxillary Impacted Canine and Upper Lateral Incisor Agenesis Treatment with "Canine First Technique" and Clear Aligners: A Case Report

The aim of this study was to show a case of an impacted canine in an adult patient with agenesis of the maxillary lateral incisor treated with clear aligners (CA). A 19-year-old male with a persistence of 5.3 and absence of 1.2 came to our department of the School of Orthodontics at the University of Federico II in Naples and asked for an aesthetic treatment. The Canine First approach was used to surgically expose the canine and pull it into the dental arch. In order to ensure long-term aesthetic, periodontal, and occlusal results, a treatment with CAs to close the space through the mesial placement of the canine and the enameloplasty of the tooth crown was performed. At the end of the treatment, the occlusal objectives were achieved.

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.

Investigation of the Relationship of Impacted Maxillary Canines with Orthodontic Malocclusion: A Retrospective Study

Impacted canines, which play an important role in smile aesthetics and functional occlusion, can lead to dental and skeletal malocclusions. In this study the aim was to evaluate the relationship between impacted maxillary canines and malocclusion. A total of 151 patients comprising 101 females and 50 males aged between 13 and 33 years were included. The groups were divided based on age, gender, skeletal and dental classification, and sector classification. Angular and linear measurements were performed on lateral cephalometric and panoramic radiographs. In panoramic radiographs, the vertical distance of the impacted canine to the occlusal plane and the angle between it and the bicondylar plane were measured and sector classification was performed according to its relationship with the root of the lateral incisor. Skeletal classification was performed according to the ANB angle on lateral cephalometric radiographs and dental classification by molar relationship via the intraoral photographs. The Chi-square test analyzed independent qualitative and quantitative data using Kruskal-Wallis and Man-Whitney U tests. The statistical significance level was accepted as p < 0.05. According to the intraclass correlation test, an excellent positive correlation was found with 0.985 for canine distance and 0.993 for canine angle between the repeated measurements. The impaction of the maxillary right canine was significantly highest in females and lowest in males. The impacted canine angle was significantly highest in sector 1 and lowest in sector 4. Distance to the occlusal plane was significantly higher in dental Class II and sector 4. It was observed that there was a considerable relationship between impacted maxillary canines and malocclusion; bilateral impacted canines were more frequent in skeletal Class III, and the distance of impacted canines to the occlusal plane increased while their angles decreased both in dental Class II and from sectors 1 to 4.

Guided Autotransplantation of Impacted Canines Using a CAD/CAM Surgical Template

Autotransplantation is a potential treatment alternative when orthodontic traction of an impacted tooth is difficult. In this article, we describe two cases of guided autotransplantation of an impacted canine using a computer-aided designed and manufactured surgical template. The impacted canine was segmented on preoperative cone-beam computed tomography images to ensure a sufficient periodontal ligament space and placement of the donor tooth with the least pressure on it. The canine was virtually transposed using a simulation program considering the adjacent teeth. The surgical template, which was connected to the occlusal stop on adjacent teeth, was designed and 3D-printed with polymer resin. The recipient site was prepared using the surgical template, followed by immediate transplantation of the surgically extracted canine into the socket. The transplanted donor tooth was positioned in planned infra-occlusion to prevent occlusal interference. It was then splinted with the adjacent teeth for initial stabilization. During follow-up, one transplanted tooth showed pulp canal obliteration and the other had suspected pulp necrosis; endodontic treatment was performed. One year after the procedure, the periradicular condition of both teeth was favorable.

Estimating the 3-D location of impacted maxillary canines: A CBCT-based analysis of severity of impaction

OBJECTIVES

The objective of the study was to quantify the 3-D location of impacted canines by measuring their linear and angular deviations in relation to adjacent structures and further evaluate impaction severity.

METHODS

CBCT images of 314 impacted canines were analysed in the sagittal, coronal and axial planes. Linear and angular measurements were recorded. Canine inclination was identified in coronal and sagittal planes. An evaluation system was constructed for analysis. Upright canine was considered as the appropriate position for fully erupted maxillary canine. Outcomes were compared between right and left sides and by gender. For categorical variables, chi-square tests were used while Mann-Whitney U test was used for continuous variables. Regression models were used to measure severity.

RESULTS

Impactions were greater in females (119/207; 57.5%). No significant differences between unilateral (100/207; 49.3%) and bilateral (107/207; 51.7%) (P > 0.05). Out of 314 impactions, 105 (33.4%) were mild, 118 (37.58%) moderate and 91 (28.98%) severe. Severe impactions were primarily buccal (44/ 91; 48.3%), in the occlusal ½ of the adjacent incisor root (38/ 91, 41.7%), mesial to the distal border of central incisor (47/91, 51.6%), with sagittal angle value + >45 ̊ (46/ 91, 50.5%) and mesial tip + >30 ̊ (86/ 91, 94.5%).

CONCLUSIONS

Severely impacted canines had their crowns buccal, closer to occlusal plane and mesial to the distal border of the central incisor with greater than 45-degree buccal inclination and greater than 30-degree mesial tip. The sagittal angle can have a significant impact on the severity of impaction. A new classification system was proposed to quantify severity.

“Canine First Technique”, An Innovative Approach in Maxillary Impacted Canines: A Case Report

Background:

Maxillary canine impaction is one of the most challenging issues in orthodontics. The best treatment protocol in these cases is still debated. The purpose of this study is to describe the management of maxillary canine impaction in an adult female patient with the “Canine First Technique”.

Case Report:

A 21-years-old female attended our dental unit seeking orthodontic treatment. Clinical examination revealed a class II relationship, the persistence of both upper deciduous canines. The panoramic X-ray and Cone Beam Computed Tomography showed bilateral palatal permanent canine displacements and close proximity between crowns of impacted canines and roots of lateral incisors. The canines were disimpacted by means of two cantilevers inserted directly in two Temporary Anchorage Devices placed palatally and when canines were near the crest, the fixed orthodontic treatment was started.

Results:

At the end of the treatment, canine Class I relationships with torque correction of canines, normal overjet and overbite, and good alignment of dental arches were achieved. The radiographic evaluation showed ideal root parallelism and preserved periodontal health in the canine region.

Conclusion:

The Canine First Technique could provide some advantages compared to conventional approaches in terms of biomechanics, esthetics, oral hygiene, and risk reduction of root resorption of upper lateral incisors.

Periodontal health of unilateral labially vs. palatally impacted maxillary canines erupted by closed eruption technique

OBJECTIVE

This study's aim was to compare the periodontal health of labially and palatally impacted maxillary canines erupted by closed eruption technique, and to compare them with the contralateral canines that served as control teeth.

MATERIALS AND METHODS

A total of 32 subjects, 17 with unilateral labially impacted maxillary canines and 15 with palatally impacted maxillary canines were enrolled in this study. Pretreatment maxillary canine variables were evaluated from initial panoramic radiographs using Nolla stage, α‑angle, d‑depth and s‑sector. The closed eruption technique was used for surgical exposure of the impacted teeth. Posttreatment periodontal parameters such as plaque index (PI), gingival index (GI), gingival bleeding index (GBI), probing depth (PD), keratinized gingival width (KGW), attached gingival width (AGW), and gingival thickness (GT) were evaluated to compare the periodontal health with the contralateral canines.

RESULTS

Intergroup comparison results exhibited insignificant differences in all periodontal parameters between the labially and palatally impacted maxillary canines. Intragroup comparison results showed a significant increase in PI, GI, GBI, and PD, and a significant decrease in AGW, KGW, and GT in the impacted teeth compared to the controls, except for PI in the palatally impacted maxillary canines.

CONCLUSION

The decrease in KGW, AGW, and GT was not associated with the pre-eruptive position of the impacted teeth. These side effects seen after orthodontic treatment of impacted teeth should be followed carefully in the long term.

Predictive factors associated with adjacent teeth root resorption of palatally impacted canines in Arabian population: a cone-beam computed tomography analysis

BACKGROUND

This study aimed to evaluate three-dimensionally the factors associated with adjacent teeth root resorption of palatally impacted canines.

METHODS

In this retrospective cross-sectional study, one-hundred and fourteen cone beam computed tomography scans with palatally impacted maxillary canines were evaluated for the presence of adjacent root resorption. Seven parameters were analyzed: alignment of maxillary incisors, presence of deciduous canines, first premolars' roots configuration, impacted canines rotation, angulation of impacted canine to the midline, contact relationship, and area of contact with adjacent teeth. The association between dependent and independent qualitative and quantitative variables was analyzed using chi-square and independent student's t-test, respectively. The multivariate analysis was performed using regression analysis. The significant value was set at P ≤ 0.05.

RESULTS

The overall incidence of vertical, horizontal impaction and adjacent root resorption were 92, 8 and 77.2%, respectively. The apical third was the most involved area (57%); resorption of a single tooth was found in 21.9% of the total sample. The most common resorbed teeth were lateral first premolars (24.6%), followed by central lateral incisors (20.2%), and lateral incisors (15.8%) of the total sample. The severity of resorption was highest in grade I (31.5%) and lowest in grade III (7.6%). Three variables showed significant differences between resorption and non-resorption groups namely; canine rotation (P < 0.013), contact relationship (P < 0.001), and area of contact with adjacent teeth (P < 0.001). Regression analysis revealed an association between adjacent root resorption and permanent canine rotation, adjacent premolars' roots configuration, contact relationship, and area of contact (P < 0.05).

CONCLUSION

Two-thirds of impacted maxillary canines showed a form of root resorption. The most commonly resorbed tooth was the lateral incisors while the least affected one was the central incisors with apical one-third being of the highest risk. The predisposing factors including the canine rotation, premolar with separated roots, contact relationship, and area of contact with adjacent teeth are to be considered for any interceptive treatment.

Interventions for promoting the eruption of palatally displaced permanent canine teeth, without the need for surgical exposure, in children aged 9 to 14 years

BACKGROUND

A permanent upper (maxillary) canine tooth that grows into the roof of the mouth and frequently does not appear (erupt) is called a palatally displaced canine (PDC). The reported prevalence of PDC in the population varies between 1% and 3%. Management of the unerupted PDC can be lengthy, involving surgery to uncover the tooth and prolonged orthodontic (brace) treatment to straighten it; therefore, various procedures have been suggested to encourage a PDC to erupt without the need for surgical intervention.

OBJECTIVES

To assess the efficacy, safety and cost-effectiveness of any interceptive procedure to promote the eruption of a PDC compared to no treatment or other interceptive procedures in young people aged 9 to 14 years old.

SEARCH METHODS

An information specialist searched four bibliographic databases up to 3 February 2021 and used additional search methods to identify published, unpublished and ongoing studies.

SELECTION CRITERIA

We included randomised controlled trials (RCT) involving at least 80% of children aged between 9 and 14 years, who were diagnosed with an upper PDC and undergoing an intervention to enable the successful eruption of the unerupted PDC, which was compared with an untreated control group or another intervention.

DATA COLLECTION AND ANALYSIS

Two review authors, independently and in duplicate, examined titles, keywords, abstracts, full articles, extracted data and assessed risk of bias using the Cochrane Risk of Bias 1 tool (RoB1). The primary outcome was summarised with risk ratios (RR) and 95% confidence intervals (CI). We reported an intention-to-treat (ITT) analysis when data were available and a modified intention-to-treat (mITT) analysis if not. We also undertook several sensitivity analyses. We used summary of findings tables to present the main findings and our assessment of the certainty of the evidence.

MAIN RESULTS

We included four studies, involving 199 randomised participants (164 analysed), 108 girls and 91 boys, 82 of whom were diagnosed with unilateral PDC and 117 with bilateral PDC. The participants were aged between 8 and 13 years at recruitment. The certainty of the evidence was very low and future research may change our conclusions. One study (randomised 67 participants, 89 teeth) found that extracting the primary canine may increase the proportion of PDCs that successfully erupt into the mouth at 12 months compared with no extraction (RR 2.87, 95% CI 0.90 to 9.23; 45 participants, 45 PDCs analysed; very low-certainty evidence), but the CI included the possibility of no difference; therefore the evidence was uncertain. There was no evidence that extraction of the primary canine reduced the number of young people with a PDC referred for surgery at 12 months (RR 0.61 (95% CI 0.29 to 1.28). Three studies (randomised 132 participants, 227 teeth) found no difference in the proportion of successfully erupted PDCs at 18 months with a double primary tooth extraction compared with extraction of a single primary canine (RR 0.68, 95% CI 0.35 to 1.31; 119 participants analysed, 203 PDCs; mITT; very low-certainty evidence). Two of these studies found no difference in the proportions referred for surgical exposure between the single and the double primary extraction groups data at 48 months (RR 0.31, 95% CI 0.06 to 1.45).  There are some descriptive data suggesting that the more severe the displacement of the PDC towards the midline, the lower the proportion of successfully erupted PDCs with or without intervention.

AUTHORS' CONCLUSIONS

The evidence that extraction of the primary canine in a young person aged between 9 and 14 years diagnosed with a PDC may increase the proportion of erupted PDCs, without surgical intervention, is very uncertain. There is no evidence that double extraction of primary teeth increases the proportion of erupted PDC compared with a single primary tooth extraction at 18 months or the proportion referred for surgery by 48 months. Because we have only low to very low certainty in these findings, future research is necessary to help us know for sure the best way to deal with upper permanent teeth that are not erupting as expected.

Three-dimensional changes in root angulation of buccal versus palatal maxillary impacted canines after orthodontic traction: A retrospective before and after study

INTRODUCTION

The aim of this study was to three-dimensionally compare the root angulation changes after orthodontic traction of buccally versus palatally maxillary impacted canines (MICs).

MATERIAL AND METHODS

This retrospective study included patients from a private dental office of both sexes, older than 12 years, with at least one unilateral or bilateral buccal or palatal MIC, no loss of permanent teeth, with complete apical closure at the beginning of traction, and with CBCTs taken at pretreatment (T₀) and after orthodontic traction (T₁). The sample was divided in two groups according to their impaction site: buccal versus palatal. In all the scans, the MIC was segmented and the root angulation changes after traction were evaluated. The assessment included the sigma angle (projected on the XZ plane or coronal tomographic view), the delta angle (projected on the XY plane or axial view) and the epsilon angle (projected on the YZ plane, or sagittal view). Intragroup comparisons were performed with Wilcoxon signed-rank tests. Intergroup comparisons were performed with t-tests or Mann-Whitney U tests. Finally, the influence of MIC characteristics on the measured angles were evaluated with multiple linear regression analyses (α=0.05).

RESULTS

Thirty-three patients (16 men, mean age: 20.38; 17 women, mean age 18.37) with forty-five orthodontically treated MIC (19 buccal versus 26 palatal) were finally included. The palatal MICs showed greater mediolateral uprighting than the buccal MICs, root displacement towards the midsagittal plane, as demonstrated by the sigma angle (palatal group: 37.58±15.08°; buccal group: 29.17±31.15°; P=0.164) and delta (palatal group: -76.90±26.55°; buccal group: -30.56±41.67°; P<0.001)angle changes. The buccal MICs showed greater anteroposterior uprighting, anterior root displacement, as demonstrated by the epsilon angle (palatal group: -4.63±12.37°; buccal group: -25.96±17.79°; P<0.001).

CONCLUSIONS

Mediolateral and anteroposterior root angulation show significant differences after traction between buccal and palatal MICs. Palatal MICs showed greater medial root displacement while buccal MICs showed greater anterior root displacement. This condition should be considered for better planning of traction and orthodontic finishing.

Management of maxillary impacted canines: A prospective study of orthodontists' preferences

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Children should be examined by the age of eight or nine years to assess for maxillary canine displacement and possible impaction.

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Maxillary impacted canines are best approached and managed through interdisciplinary approach involving a pediatric dentist, orthodontist, oral surgeon, and periodontist.

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The pediatric dentist can be the first specialist for early diagnosis and management of maxillary impacted canines, which can be achieved by facilitating the maxillary canine’s eruption and guiding it to its proposed location in the dental arch.

Background

Maxillary canines are considered the most commonly impacted teeth, after the third molars. Orthodontists have different preferences on how to approach maxillary impacted canines (MIC). The objective of this article was to investigate orthodontists’ approach to managing MIC.

Material and methods

A cross-sectional study comprising a comprehensive survey with 22 questions was sent to practicing orthodontists. This study explored the preferred diagnostic measures, surgical techniques, materials, and mechanics utilized to manage MIC;104 responses were returned.

Results

Palatal impaction was reported to be encountered more often than labial impaction by 60% of the respondents. In 62% of the respondents, an oral and maxillofacial surgeon was the specialist preferred to perform the surgical exposure. In 66%, the choice of required surgical techniques was reported as a joint decision between orthodontists and other specialists who perform the surgery. Cone-beam computed tomography (CBCT) was reported to be the diagnostic x-ray of choice. The gold button with a chain was the preferred bonded attachment in 86% of cases. Less than half of the respondents bonded the attachments themselves during surgical exposure. A clear plastic retainer was the preferred retainer in 61% of the respondents, and 43% of the respondents tended to use a closed exposure technique. Coe-pak^TM was the preferred surgical pack for orthodontists who prefer an open exposure technique. Piggyback (double wire) was the preferable mechanic to move a palatally impacted canine.

Conclusion

Our findings indicate that there are variations among orthodontists on how to manage MICs in terms of diagnostic methods, surgical management, materials, and mechanics.

Three dimensional movement analysis of maxillary impacted canine using TADs: a pilot study

BACKGROUND

The aim of the present study was to compare two different anchorage systems efficiency to disinclude impacted maxillary canines using as evaluation tool superimposed Cone Beam Computed Tomography (CBCTs).

METHODS

The study has been conducted with two parallel groups with an allocation ratio of 1:1. Group test received treatment using as anchorage a miniscrew, control group was treated using an anchorage unit a trans palatal arch (TPA). Both groups received a calibrated traction force of 50 g. CBCT before treatment and 3 months after traction were superimposed and canine tip and root movement were evaluated in mm/month ratio.

RESULTS

No differences were observed between groups for apex displacement, tip displacement and observation timespan. Twenty-two patients (12 female, 10 male, mean age:13.4 years) undergoing orthodontic treatment for impacted maxillary canines were recruited for this study. No differences were observed between groups for apex displacement, tip displacement and observation timespan.

CONCLUSIONS

The present pilot study provided no evidence that indirect anchorage on miniscrews could make canine disimpaction faster than anchorage on a TPA. An apex root movement of 0.4-0.8 mm per month was found, while average canine tip movement ranged between 1.08 mm and 1.96 mm per month. No miniscrews failures were observed.

TRIAL REGISTRATION

The study reports the preliminary results of the randomized clinical trial registered at www.register.clinicaltrials.gov (registration number: NCT01717417 ).