Impaction of maxillary canines and its effect on the position of adjacent teeth and canine development: A cone-beam computed tomography study

The sacrosanct canine: Considerations for the extraction of severely displaced, or impacted maxillary canine(s)

OBJECTIVE

The maxillary canines have long been considered critical for dental function and aesthetics, with traditional practice prioritizing their preservation and alignment. However, this view often stems from outdated teachings rather than evidence-based principles, since there is no scientific support for the concept of canine-protected occlusion. Therefore, this commentary paper provides justification for extraction of severely impacted maxillary canines with first premolar substitution.

RESULTS

In cases of severely impacted maxillary canines, orthodontic alignment may be associated with higher morbidity, unpredictable outcomes, prolonged treatment times, and increased patient burden. As an alternative, extracting the impacted canines and substituting the first premolars offers a viable, efficient solution that can achieve functional and aesthetic outcomes with fewer complications.

CONCLUSION

This paper challenges traditional perspectives on the management of impacted canines, advocating for an evidence-based approach that prioritizes patient-centered care.

Exploring the Link Between Adjacent Lateral Incisor Morphology and Unilateral Maxillary Canine Impaction: A Cone-Beam Computed Tomography Study

INTRODUCTION

The maxillary canine plays a pivotal role in dental aesthetics, occlusion, and function because of its strategic anatomical positioning. However, the eruption of maxillary canines is a complex process that often leads to impaction. The anatomical and morphological characteristics of adjacent teeth, particularly the maxillary lateral incisors (MLIs), are believed to influence the eruption of maxillary canines. This study aimed to investigate the association between the morphology of MLI and unilateral impacted maxillary canines (IMCs) while also identifying potential predictors of such impactions.

MATERIALS AND METHODS

This retrospective study analyzed cone-beam computed tomography (CBCT) scans of 40 patients with unilateral IMC conducted between January 2020 and December 2023. Patients were selected based on the inclusion criteria that required intact MLIs adjacent to both impacted and non-impacted canines. CBCT imaging was performed using standardized protocols to assess crown dimensions, root length, angulation, and spatial relationships of the lateral incisors. The measurements were recorded independently by two calibrated observers. Statistical analyses included independent t-tests and multivariate logistic regression, with significance set at p < 0.05.

RESULTS

Significant differences were observed in the morphological parameters of the MLI between the impacted and non-impacted sides. Root length and full length were significantly smaller on the impacted side (p < 0.05), whereas mesiodistal (MD) dimensions showed no significant difference. Labiolingual (LL) dimensions and angular measurements revealed significant variations, with mesially inclined and labially displaced roots on the impacted side. Sex differences were noted, with females exhibiting smaller root lengths and buccolingual (BL) dimensions than males. Multivariate logistic regression identified sex, root length, MD width, and angulation with the mid-sagittal plane (MSP) as significant predictors of IMC.

CONCLUSION

Unilateral IMC were significantly associated with smaller root lengths, LL dimensions, and mesially inclined roots of MLI.

Effects of single unilaterally impacted mesiodens on maxillary central incisors: A 3D quantitative assessment based on cone-beam computed tomography

BACKGROUND

Mesiodens usually lead to the malposition and abnormal morphology of maxillary central incisors.

AIM

To evaluate the detrimental effects of single unilaterally impacted mesiodens on the three-dimensional positions and morphology of the maxillary central incisor using cone-beam computed tomographic (CBCT) examinations.

DESIGN

A total of 321 patients aged 5-17 years with single unilaterally impacted mesiodens were included and divided into two groups: mixed dentition group (5-10 years) and early permanent dentition group (11-17 years). CBCT data for these patients were retrospectively analyzed to compare the inclination, rotation, angulation, and morphology of maxillary central incisors between the affected and contralateral control sides. The morphology, orientation, and spatial location of mesiodens were also assessed.

RESULTS

Central incisors on the affected side showed significant palatal crown inclination, shorter root, shorter tooth, and greater crown-to-root ratio in both groups, whereas significant mesial crown angulation was only observed in the mixed dentition group.

CONCLUSION

Impacted mesiodentes result in the displacement and impaired root development of central incisors, strongly suggesting timely clinical management of these abnormal teeth, such as the early removal of mesiodens and orthodontic treatments.

Two-Dimensional Radiographic Diagnosis of Maxillary Canine Impactions

Background: The primary aim of this study was to evaluate, using conventional radiographic imaging, the height, angulation, and mesiodistal position of impacted maxillary canines to determine if these variables are significantly associated with the palatal or buccal positioning of the tooth. Methods: A retrospective analysis was conducted on all patients diagnosed and treated for at least one impacted maxillary canine over a 4-year period in the Principality of Asturias. The final sample included 159 impacted canines. The variables analyzed were age, gender, associated pathology, location, angulation, height, mesiodistal position, buccopalatal position, and treatment method. Follow-up periods ranged from 12 to 50 months. Results: The mean age of the patients was 21 years (range 10-41 years), with most cases occurring in patients aged 14 to 30 years. Females accounted for 66.1% of the sample, with a female-to-male ratio of 1.95:1. The type of treatment (extraction/traction, surgical-orthodontic approach) was significantly associated with patient age. Additionally, the proximity of the impacted canine crown to the palatal or buccal cortices was significantly related to the treatment choice. However, no significant relationship was observed between the palatal/buccal position of the canine crown and its height or angulation. Conclusions: In the present work, the upper canines included by the palatal did not have a greater height or angulation than the canines included by the vestibule.

Root volume measurements of maxillary canines and lateral incisors in patients with unilateral maxillary canine impaction

OBJECTIVE

This study aimed to assess root volumes of maxillary canines and adjacent lateral incisors in patients with unilateral maxillary canine impaction.

METHODS

This cross-sectional study was performed on cone-beam computed tomography (CBCT) scans of 100 patients (49 females and 51 males) with unilateral maxillary canine impaction. The images were loaded in Planmeca Romexis Viewer, and root layers between the cementoenamel junction and apex were reconstructed at 600-µm intervals. At each layer, the root boundary was marked, and finally, the root volume was calculated by multiplying the layers' area by the thickness of 600 µm. The root size of canines and lateral incisors was compared between the impaction and normal eruption sides.

RESULTS

Sixty-two patients showed buccal canine impaction, and 38 presented palatal impaction. The mean root volume of canines on the impaction side was significantly greater than that on the normal eruption side; either the tooth was buccally or palatally impacted (p<0.001). The lateral incisors on the side of buccally-impacted canines showed a significantly smaller root volume than that of the contralateral side (p<0.001). However, there was no significant difference in the root size of lateral incisors between the two sides in cases presenting palatal canine impaction (p=0.177).

CONCLUSION

The difference in root volume of canines between the two sides can serve as an indicator of canine impaction. The reduction in the root size of the lateral incisor on the side of the buccally impacted canine may be due to root resorption created by pressure from the canine's crown.

Buccolingual inclination of posterior dentition in maxillary impacted canine patients using quadrant analysis - A cone-beam computed tomographic study

BACKGROUND

To examine the buccolingual inclination of maxillary posterior teeth, curve of Wilson, and transversal dimensions in palatally impacted maxillary canine patients, compared to controls by cone-beam computed tomography (CBCT).

MATERIALS AND METHODS

Pre-treatment images of 22 bilateral, 32 unilateral impacted maxillary canine patients and 30 controls were included. All patients had palatally impacted canines, with no posterior cross-bite. Data were reclassified in quadrants according to the presence of impaction, as the impaction quadrant (right and left quadrants of 22 bilateral impacted cases, and quadrants presenting impaction of 32 unilateral cases, n = 76), unaffected quadrant (quadrant without impaction in 32 unilateral cases, n = 32) and the control quadrant (right and left quadrants of 30 controls, n = 60) to evaluate the buccolingual inclination angle, transversal width, and arch perimeter. Additionally, comparisons were made regarding curve of Wilson and total arch perimeter among bilateral and unilateral impaction groups with the control group. Statistical analysis was performed by one-way ANOVA and Kruskal Wallis tests. Tukey or Dunn tests were used for comparisons between groups in pairs.

RESULTS

No significant difference was found for the buccolingual inclination of maxillary posterior teeth and curve of Wilson among groups. The buccolingual inclination of canines in the impaction quadrant was significantly lower than the other quadrants (p < 0.001). Basal bone width at the level of second premolars, and alveolar width at both premolars were significantly narrower in the impaction quadrant than in the unaffected quadrant (p < 0.05). Dental arch width at the level of first premolar was significantly decreased in the impaction quadrant compared to other quadrants (p < 0.05). Arch perimeter was significantly reduced in the impaction quadrant than in the unaffected quadrant (p < 0.05).

CONCLUSION

The presence of bilateral or unilateral palatally impacted maxillary canines did not effect the buccolingual inclination of posterior teeth, and curve of Wilson. Transverse discrepancy was evident in the impaction quadrant even in the absence of posterior cross-bite. Quadrant analysis was particularly useful in evaluating asymmetry for basal bone and alveolar bone widths in the premolar region in patients with unilateral palatally impacted maxillary canine patients.

A hierarchical deep learning approach for diagnosing impacted canine-induced root resorption via cone-beam computed tomography

OBJECTIVES

Canine-induced root resorption (CIRR) is caused by impacted canines and CBCT images have shown to be more accurate in diagnosing CIRR than panoramic and periapical radiographs with the reported AUCs being 0.95, 0.49, and 0.57, respectively. The aim of this study was to use deep learning to automatically evaluate the diagnosis of CIRR in maxillary incisors using CBCT images.

METHODS

A total of 50 cone beam computed tomography (CBCT) images and 176 incisors were selected for the present study. The maxillary incisors were manually segmented and labeled from the CBCT images by two independent radiologists as either healthy or affected by root resorption induced by the impacted canines. We used five different strategies for training the model: (A) classification using 3D ResNet50 (Baseline), (B) classification of the segmented masks using the outcome of a 3D U-Net pretrained on the 3D MNIST, (C) training a 3D U-Net for the segmentation task and use its outputs for classification, (D) pretraining a 3D U-Net for the segmentation and transfer of the model, and (E) pretraining a 3D U-Net for the segmentation and fine-tuning the model with only the model encoder. The segmentation models were evaluated using the mean intersection over union (mIoU) and Dice coefficient (DSC). The classification models were evaluated in terms of classification accuracy, precision, recall, and F1 score.

RESULTS

The segmentation model achieved a mean intersection over union (mIoU) of 0.641 and a DSC of 0.901, indicating good performance in segmenting the tooth structures from the CBCT images. For the main classification task of detecting CIRR, Model C (classification of the segmented masks using 3D ResNet) and Model E (pretraining on segmentation followed by fine-tuning for classification) performed the best, both achieving 82% classification accuracy and 0.62 F1-scores on the test set. These results demonstrate the effectiveness of the proposed hierarchical, data-efficient deep learning approaches in improving the accuracy of automated CIRR diagnosis from limited CBCT data compared to the 3D ResNet baseline model.

CONCLUSION

The proposed approaches are effective at improving the accuracy of classification tasks and are helpful when the diagnosis is based on the volume and boundaries of an object. While the study demonstrated promising results, future studies with larger sample size are required to validate the effectiveness of the proposed method in enhancing the medical image classification tasks.

Treatment duration by morphology and location of impacted maxillary canines: A cone-beam computed tomography investigation

INTRODUCTION

This study aimed to identify whether patients with impacted maxillary canines take longer to treat than orthodontic patients without an impacted canine. We also sought to identify factors that are predictive of increased treatment duration in patients with impacted maxillary canines and treated by surgical exposure.

METHODS

A retrospective investigation of 37 patients with an impacted maxillary canine, treated by surgical exposure and fixed appliance therapy, was undertaken. In addition, an age- and sex-matched control group of 39 patients (without impacted canines) was also collected. Patient age, sex, and total treatment duration were recorded. For patients with an impacted canine, patient records and pretreatment cone-beam computed tomography datasets were assessed. Point coordinates identifying relevant landmarks were recorded, and a geometric method was used to calculate variables describing canine location, orientation, and apical morphology.

RESULTS

Controlling for age and sex, linear regression identified a statistically significant increase in treatment duration of 46.7 and 41.5 weeks for palatal and labial/midalveolar impacted canines, respectively, vs controls (P <0.002). Age and sex of patients with impacted canines collectively affected treatment duration (P = 0.04), with females of increased age being treated faster than younger males. Rotation of the impacted canine crown had a highly significant effect on treatment duration, with every degree of rotation increasing treatment duration by 0.32 weeks (P <0.001). There was a significant degree of multicollinearity between the other radiographic variables. Collectively, radiographic variables describing canine displacement significantly prolonged treatment duration (P <0.001) and explained 29.8% of the variability in total treatment time. The apical morphology of impacted maxillary canines was significantly associated with increased treatment duration (P = 0.01) and explained 11.3% of the overall treatment variability (P = 0.01).

CONCLUSIONS

Increased total treatment duration of surgically exposed impacted maxillary canines is associated with increasing mesiopalatal canine crown rotation, worsening displacement, and hooked apical morphology.

Prevalence, etiology, clinical features and management associated with impacted and transmigrated mandibular canines: a systematic review

BACKGROUND

The occurrence of mandibular canine impaction and/ or transmigration is a rare clinical entity but diagnosis and treatment planning is of clinical significance. The associated etiological factors and the clinical guidelines for the management are still not clear. The aim of this systematic review was to summarize the available data to report the prevalence and identify the etiological factors, clinical features, and various treatment outcomes in patients with mandibular canine impaction and/or transmigration.

METHODS

The review protocol was registered in PROSPERO (CRD42021222566) and was conducted and reported according to the PRISMA and Cochrane Handbook / Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A computerized search of studies published up to April 30, 2023, was conducted using the following databases: Medline, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Scopus, Web of Science, and Latin American and Caribbean Health Sciences Literature. A manual search of the reference and citation lists of eligible articles and existing systematic reviews for any additions were also conducted. The Newcastle-Ottawa Scale quality assessment tool was used to assess the studies' quality.

RESULTS

After removing 6 duplicates, 3700 articles were identified. For the final analysis, 19 studies published between 1985 and 2023 met all the eligibility criteria and were included. A total of 7 studies presented as good and 12 studies presented as satisfactory. Patients were screened in ten studies and diagnostic records from archives were retrieved in nine studies. The total number of diagnostic records screened was 138.394, and the total number of patients from the included studies was 43.127.

CONCLUSIONS

Based on the findings from this systematic review, the prevalence of mandibular canine impaction ranged from 0.008% to 1.29% while canine transmigration from 0.12% to 0.98%. Crowding of the mandibular arch, the presence of a retained deciduous canine, and odontoma or cyst are the etiological factors more commonly associated with mandibular canine impaction and or transmigration. Surgical extraction and surgical exposure followed by orthodontic traction are the two most frequently carried out treatment modalities in the management of mandibular canine impaction and or transmigration.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The diagnostic accuracy of cone-beam computed tomography and two-dimensional imaging methods in the 3D localization and assessment of maxillary impacted canines compared to the gold standard in-vivo readings: A cross-sectional study

BACKGROUND

Although the widespread cone-beam computed tomography (CBCT) is a diagnosing tool for impacted canines, the surgical exposure-based diagnostic accuracy of this 3D imaging modality has not been established yet. Therefore this study aimed to (1) compare the accuracy of CBCT- and 2D-based interpretations of impacted canine and its relationships with the neighbouring structures with the gold standard (GS) readings, (2) and calculate the diagnostic accuracy, sensitivity, and specificity values of the variables assessed using CBCT and 2D methods.

MATERIAL AND METHODS

Patients with unilateral impacted maxillary canines (IMCs) planned for surgical extraction between 2016-2018 were checked in-depth to include in this cross-sectional study. For each patient, 2D and 3D radiographic records were obtained and assessed by eight postgraduate orthodontic students. These assessments were compared with the GS readings based on surgical exposure and direct vision of the IMCs. To compare 2D- and CBCT-based assessments with the GS values, Cochran's Q tests, Friedman's tests, McNemar's, McNemar-Bowker's, and Wilcoxon tests were applied.

RESULTS

A total of 17 patients (6 males, 11 females; mean age: 20.52±3.98 years) were randomly selected and included in this study. Significant differences were found between the CBCT-based assessments and the GS only concerning shape and bony coverage of the IMC (P=0.001 and P<0.001, respectively). On the contrary, there were significant differences between the 2D-based assessments and the GS regarding all the assessed variables except for the ankylosis and the proximity to the adjacent teeth (P=0.424, and P=0.080, respectively). CBCT-based assessments had remarkably higher values of diagnostic accuracy, sensitivity, and specificity compared to 2D-based ones.

CONCLUSIONS

The diagnostic accuracy of CBCT outperformed 2D radiography in localizing the IMC (labiopalatal, mesiodistal, and vertical location), detecting root apex development of the IMCs, and the resorption of the adjacent incisors. Although both 2D and 3D techniques showed the same ability in the diagnosis of IMCs ankylosis, the diagnostic accuracy of CBCT was superior. However, both techniques inaccurately determined the shape of the impacted canine and the bony coverage.

Comparison of palatal volume and surface changes between bone-borne and tooth-tissue-borne maxillary expansion on cone beam computed tomography digital cast models

OBJECTIVES

To compare the changes of palatal volume and area in patients treated with tooth-tissue-borne palatal expanders (conventional Haas) and miniscrew-supported palatal expanders (modified Haas).

MATERIALS AND METHODS

The sample included casts of 22 patients treated as part of a clinical study at the Department of Orthodontics, Al-Azhar University, to correct their crossbite malocclusion. Patients were divided equally into two groups upon arrival. The first group, with a mean age of 12 years and 6 months, received the miniscrew-supported palatal expander. The second group, with a mean age of 12 years and 2 months, received the Haas design-palatal expansion appliance. Pre- and post-expansion dental casts were cone beam computed tomography scanned and the slices were constructed into 3D volumes. Fully automated superimposition was done for pre- and post-expansion 3D models. Palatal volume and area were determined, and all measurements were carried out blindly. Paired t-test was used to assess the mean differences within each group and Welch's t-test was applied to assess the mean changes between the two groups. Shapiro-Wilk test was used to test for the normality of the data.

RESULTS

There were no statistical differences in volume changes either within each group or between the groups. Although area changes were statistically significant within each group, the difference between the groups was not significant.

CONCLUSIONS

Changes that result from the use of either method to expand the upper arch occur primarily in the shape of the palate, but not in its size.

Dental anomalies in an Albanian orthodontic sample: a retrospective study

BACKGROUND

To evaluate the prevalence and the distribution of dental anomalies in an Albanian orthodontic sample.

METHODS

For this retrospective study, a sample of panoramic radiographs (PR) of n. 779 (456 F and 323 M, mean age of 15.1 ± 5.5 years) Albanian subjects with no genetic syndromes or craniofacial malformations (e.g., cleft lip/palate), history of extraction, trauma or previous orthodontic treatment drawn from the archives of the University Dental Clinic Our Lady of Good Counsel, was examined. The inclusion criteria were: subjects from 8 to 30 years of age, good quality of PRs in order to allow the assessment of crown and root development. For different dental anomalies, both the prevalence and the association were evaluated by using Chi-square test (p < 0.05).

RESULTS

24.4% of the sample had at least one dental anomaly and 4.6% had more than one. The following dental anomalies were most prevalent: hypodontia (9.8%), dental impaction (7.6%), and ectopic eruption (5.3%). No statistically significant correlation was found between males and females (p > 0.05).

CONCLUSIONS

The most common anomalies in this group are found to be those of number and position, and only radiological investigations can reveal either of these anomalies. Early diagnosis of dental anomalies can contribute to prevent their complications and to establish the most suitable therapy to achieve a functional occlusion.

The labiopalatal impacted canine: Accurate diagnosis based on the position and size of adjacent teeth: A cone-beam computed tomography study

INTRODUCTION

Labiopalatal impacted canines (L-PICs) occur when the canines lie between central and lateral incisors, with their tip palatal to the central incisor and part of their crown labial to the lateral incisor. Because of their unusual position, they are often misdiagnosed, and their orthodontic resolution fails. This study aims to provide clinicians with pathognomonic features for early and accurate positional diagnosis of L-PICs.

METHODS

The L-PIC sample included 21 subjects with full diagnostic records. The control group of normally erupted canines was taken from a previous study. Clinical photographs, 2-dimensional radiographs, and cone-beam computed tomography were used to evaluate the positions of the adjacent incisors and first premolars, the canine incisor index, and the mesiodistal width of the lateral vs central incisors.

RESULTS

Central incisors adjacent to L-PICs showed significant mesial root angulation, labial root inclination, and mesiolabial crown rotation, whereas lateral incisors presented significant distal root angulation, palatal root inclination, and mesiolabial crown rotation, in comparison to controls. The roots of the central and lateral incisors were divergent, in contrast to the controls, in which they were slightly convergent. The first premolar positions were not affected. The mean canine incisor index was significantly bigger in L-PICs vs the controls, suggesting a palatal canine. The lateral incisor widths were similar between the groups.

CONCLUSIONS

This study provides the orthodontist with evidence-based clinical and radiographic red flags for diagnosing L-PIC, which may allow timely initiation of orthodontic treatment and correct planning of mechanotherapy.

Facial Scanning Accuracy with Stereophotogrammetry and Smartphone Technology in Children: A Systematic Review

The aim of the study was to systematically review and compare the accuracy of smartphone scanners versus stereophotogrammetry technology for facial digitization in children. A systematic literature search strategy of articles published from 1 January 2010 to 30 August 2022 was adopted through a combination of Mesh terms and free text words pooled through boolean operators on the following databases: PubMed, Scopus, Web of Science, Cochrane Library, LILACS, and OpenGrey. Twenty-three articles met the inclusion criteria. Stationary stereophotogrammetry devices showed a mean accuracy that ranged from 0.087 to 0.860 mm, portable stereophotogrammetry scanners from 0.150 to 0.849 mm, and smartphones from 0.460 to 1.400 mm. Regarding the risk of bias assessment, fourteen papers showed an overall low risk, three articles had unclear risk and four articles had high risk. Although smartphones showed less performance on deep and irregular surfaces, all the analyzed devices were sufficiently accurate for clinical application. Internal depth-sensing cameras or external infrared structured-light depth-sensing cameras plugged into smartphones/tablets increased the accuracy. These devices are portable and inexpensive but require greater operator experience and patient compliance for the incremented time of acquisition. Stationary stereophotogrammetry is the gold standard for greater accuracy and shorter acquisition time, avoiding motion artifacts.

Comparative analysis of intraoral scanners accuracy using 3D software: an in vivo study

Background

The purpose of the present in vivo study was to compare the accuracy, in terms of trueness, between full-arch digital impressions of different intraoral scanning systems, using as a reference the ideality of the conventional impression technique.

Methods

Polyvinyl siloxane (PVS) two-step technique impressions of 27 subjects were taken, and the stone casts were scanned using desktop scanners R500 3Shape. For each arch, in vivo scans were taken with intraoral scanners Carestream CS3600, CEREC Omnicam and Trios 3Shape. All the files were compared, superimposing them on the reference model to calculate the total 3D and 2D deviations. The efficiency of the digital and conventional workflows was evaluated by measuring the work time in minutes. Statistical analyses were performed using R software (R Core Team 2020) with a p-value < 0.05.

Results

The three intraoral scanners differed from the PVS impression by differences of the order of 100–200 µm, and there was a trend of greater imprecision in the molar area in both dental arches. In comparison with PVS technique, CEREC tended to reduce the size of the impression, Trios presented the trend of greater precision, and Carestream showed minor differences the transversal distance. The areas of greatest discrepancy both in excess and in defect with respect to the PVS impression were the molar areas and incisal margins. Trios 3Shape recorded the shortest times and therefore with a more performing speed.

Conclusion

The Trios 3Shape was found to be the most accurate single-tooth scanner, while the Carestream CS 3600 showed better inter-arch diameter performance compared to PVS impressions. The 3D and 2D analyses showed a trend of greater distortion of the impressions compared to the conventional one in the molar region.

Introducing surface-to-surface matching technique to evaluate mandibular symmetry: A retrospective study

Objectives

This study introduced a three-dimensional (3D) surface-to-surface matching technique to evaluate the mandibular symmetry of teenagers and adults with unilateral second molar scissor bite.

Methods

The targets came from 73 cone-beam computed tomography (CBCT) images with unilateral second molar scissor bite, including teenagers (n = 30) and adults (n = 43). 73 images without scissor bite and matched in sex and age were selected as controls. The scans were developed into 3D mandible models and seven mandibular functional unit models, including condylar process (Co), coronoid process (Cr), mandibular ramus (Ra), mandibular angle (Ma), alveolar process (Ap), mandibular body (Mb) and chin process (Ch). The surface-to-surface matching technique was introduced. 3D deviation analysis and matching percentages calculation were performed and compared to evaluate the symmetry of the mandible.

Results

Comparisons were made between the study samples and control samples. For teenagers, the matching percentages of the entire mandible (55.31 ± 7.24%), Mb (69.04 ± 9.22%) and Co (65.19 ± 10.67%) in the study group were lower than that of the entire mandible (60.87 ± 6.38%) (P <0.01), Mb (75.0 ± 8.71%) (P <0.05) and Co (70.25 ± 8.20%) (P <0.05) in the control group. While Ap, Ra, Ch, Cr and Ma showed no statistically significant differences (P >0.05). For adults, the matching percentages of the entire mandible (48.88 ± 9.77%), Ap (65.83 ± 11.21%), Mb (64.43 ± 12.03%), Ch (79.17 ± 10.29%), Ra (64.11 ± 9.84%) and Co (61.08 ± 11.64%) in the study group were lower than the entire mandible (59.28 ± 5.49%) (P <0.01), Ap (73.65 ± 9.10%) (P <0.01), Mb (71.66 ± 8.40%) (P <0.01), Ch (83.86 ± 5.59%) (P <0.05), Ra (68.54 ± 7.87%) (P <0.05) and Co (66.20 ± 10.62%) (P <0.05) of the control group. Only Cr and Ma showed no statistically significant differences (P >0.05).

Conclusion

Mandibular asymmetry was observed in both teenagers and adults with unilateral second molar scissor bite. Moreover, compared with teenagers, more mandibular units of adult patients were affected.

Clinical significance

Based on the surface-to-surface matching technique, the symmetric and morphological information of the mandible can be converted into visual color maps and quantitative descriptions. This method can bring convenience to the study of the growth of mandible, orthodontic treatment and orthognathic surgery design.

Experimental Analysis of the Use of Cranial Electromyography in Athletes and Clinical Implications

Background: Cranial surface electromyography is assumed to analyze the correlation between the stomatognathic apparatus and the muscular system and its implications on the physical status of professional athletes. The purpose of this paper is to evaluate surface cranial electromyography as an aid in the diagnosis and treatment of occlusal and muscular disorders in professional athletes. Methods: A sample of 25 athletes (mean age 23 years, 20 men and 5 women) underwent electromyographic recording; among them, 13 had a sports injury condition (symptomatic athletes), while 12 were in perfect physical condition (asymptomatic athletes). At odontostomatological examination, 6 showed cranio-mandibular disorders (dysfunctional athletes), while 19 showed no disorders (functional athletes). The treatment plan to resolve the symptoms of the dysfunctional athletes was chosen based on the electromyographic data. One month after the start of therapy with an occlusal splint, a follow-up was performed, and the results were compared with the initial data. Results: Statistical analysis showed that the chosen therapy following the use of electromyography was effective in 72% of cases, while 28% of patients did not respond to therapy (p = 0.028). Conclusions: The use of cranial electromyography in competitive athletes is a valuable tool in therapeutic choice aimed at balancing occlusal loads and improving the patient’s global tonic postural attitude, resulting in positive feedback in the qualitative assessment of sports performance.

Stability of transverse dental arch dimension with passive self-ligating brackets: a 6-year follow-up study

Objective

The stability of the transverse expansion in passive self-ligating bracket treatments is a debated topic in orthodontics. However, to date, only 3 reports are available in the literature, with the maximum follow-up of 3 years after the end of therapy. The present study aims to evaluate the stability of orthodontic treatment with self-ligating brackets in a 6-year follow-up period of time.

Materials and methods

A sample of 56 non-extractive cases (of whom 33 females, mean age 16.9, SD = 9.0 years) consecutively treated with Damon® system was retrospectively selected. All patients received fixed retainers from canine to canine in both arches at the end of treatment, and no removable retainers were provided. The mean values of the transverse intercusp, transverse centroid and transverse lingual distances were evaluated for all teeth from canines to second molars in both arches. Each measure was calculated at four timepoints: before treatment (T0), at the end of treatment (T1), one year after treatment (T2) and six years after treatment (T3). Transverse diameters were measured for all teeth, starting from the canines to the second molars, for a total of 1680 observations, and subsequently compared in order to evaluate intra-treatment and post-treatment modifications.

Results

There were increases in all transverse dental measurements during active treatment. A statistically significant (p < .05) reduction of the transverse diameter was found, for upper and lower premolars, from T1 to T3.

Conclusion

The 6-year follow-up analysis detected that the initial transverse expansion showed a statistically significant relapse in premolars. No relapse was detected at the level of canines, due to the presence of fixed retainers, and minimal at first molars.

Evaluation of the Effectiveness on Dentin Hypersensitivity of Sodium Fluoride and a New Desensitizing Agent, Used Alone or in Combination with a Diode Laser: A Clinical Study

(1) Background: Dentine Hypersensitivity (DH) is a frequent clinical problem that causes long-term painful discomfort to patients and is a diagnostic and therapeutic challenge for dentists. The aim of this research was to verify the efficacy of a Sodium Fluoride (NaF) gel and the VivaSens® varnish used alone or in combination with a Creation Soft Diode Laser (DL) to treat DH pain. (2) Methods: The study included 121 Non-Carious Cervical Lesions (NCCLs) in 48 patients who complained of DH pain of variable intensity, between 4 and 7 points in VAS, after application of a cold stimulus. Four study groups of 12 patients each were created and subjected to four different types of treatment. Group 1 comprised 27 NCCLs with a total VAS score of 142, who received a topical treatment of NaF. Group 2 comprised 34 NCCLs with a total VAS score of 179, who were treated with NaF in association with DL. Group 3 comprised 31 NCCLs with a total VAS score 172, who received the VivaSens varnish. Group 4 comprised 29 NCCLS with a total VAS score of 155, who were treated with VivaSens in association with DL, using a power of 0.2 Watt in continuous emission and a fiber of 400 µm diameter. (3) Results: The results for each NCCL were evaluated by the cold stimulus response and recorded according to the VAS at the end of each treatment (t1) as well as after one week (t2), 1 month (t3), and 6 months (t4). All treatments resulted in pain relief at all study times, but the best results were obtained for Group 4 at t1, with a total VAS score of 26, and for Group 2 at t2, t3, and t4, with total VAS scores of 41, 51, and 65, respectively. (4) Conclusions: The treatment with VivaSens allowed pain relief immediately after its application, but the greatest long-term benefits (t2, t3, and t4) were obtained with the topical application of NaF associated with a DL.

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.

Dento-Skeletal Class III Treatment with Mixed Anchored Palatal Expander: A Systematic Review

Bone-anchored appliances for the treatment of Class III malocclusions have recently been found to reduce the dentoalveolar effects caused by conventional tooth-borne devices while also improving orthopaedic outcomes in growing patients. The goal of this systematic review was to compare the outcomes of skeletal Class III interceptive treatment with dental anchoring devices to those achieved with mixed anchored palatal expanders. The inclusion criteria were as follows: patients who were treated with hybrid anchored palatal expanders and different maxillary advancement appliances. Study quality was estimated using the Newcastle–Ottawa scale. A search on the Pubmed, Scopus, Embase and Cochrane Library databases yielded 350 papers. Following the initial abstract selection, 65 potentially acceptable papers were thoroughly examined, resulting in a final selection of 9 articles. The results in the short-term showed that combined tooth-borne and bone-borne appliances for rapid maxillary expansion might be recommended in protocols of skeletal Class III treatment to obtain more skeletal effects and reduce side effects on the upper teeth.

Dental Arch Changes with Two Different Trans-Palatal Arch

Background:

Rapid maxillary expansion (RME) is a dentofacial orthopedic treatment often used to treat patients with narrow palate and transverse maxillary growth deficiency.

Introduction:

This treatment leads to correction of posterior dental crossbites, coordination of the upper and lower arches and gaining arch perimeter in patients with tooth size/arch size discrepancies. To stabilize the results obtained with RME and to limit or avoid the relapse, the use of Transpalatal Arch (TPA) would be recommended.

Objectives:

The aim of this study is to evaluate short-term maxillary changes in patients treated with RME followed by TPA with and without palatal arms.

Materials and Methods:

30 patients, 16 females and 14 males (mean age of 9.7 yrs ranging between 9 and 12), were treated by expansion with palatal Hyrax-type expander. After this period, it was removed and one of the two different types of TPA was used.

The two different TPA were a 0.036-inch stainless steel wire with a loop directed mesially in the middle, one maintained the original design (TPA), the second one presented arms extended to canines (TPAa). Dental casts were collected for each patient for each treatment step; before (T0), after expansion (T1) and after TPA or TPAa (T2). To assess differences in dental arches after the two treatment phases, three-dimensional (3D) dental casts were used to make more predictable measurements compared with caliper measurements that presented intra-examiner and inter-examiner measurements errors.

Results:

In TPAa group, differences between the value at the end of the retention period and at the end of expansion showed no statistical significance. Instead in TPA group, the same measurements suggested a reduction of value in almost all dental transverse diameters. Statistically significant differences in dental measurements were found between TPAa and TPA.

Conclusion:

Results confirm the hypothesis that TPAa can allow to better maintain dental transverse dimensions.

Root Resorptions on Adjacent Teeth Associated with Impacted Maxillary Canines

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

Dentoskeletal effects of early class III treatment protocol based on timing of intervention in children

Background

To detect the optimal timing of intervention based on different cervical vertebral maturation stage (CS1-2 vs. CS3-4) for the treatment of Class III malocclusion with early Class III protocol.

Methods

A total sample of 43 patients (23 females, 20 males) ranging between 7 and 13 years of age with dentoskeletal Class III malocclusion treated with the modified SEC III (Splints, Elastic and Chincup) protocol divided into two groups based on the cervical vertebral maturation stages (CS1-2 and CS3-4) was included in this retrospective observational longitudinal study. Patient compliance was assessed using a 2-point Likert scale. Statistical comparisons between the two groups were performed with independent sample t tests.

Results

No statistically significant differences for any of the cephalometric variables describing the baseline dentoskeletal features were found between the two groups except for the mandibular unit length that was significantly greater in the pubertal group (P = 0.005). The modified SEC III protocol produced favorable sagittal outcomes in both groups, whereas no statistically significant T1-T2 changes were found between the CS1-2 and CS3-4 groups for any of the angular and linear measurements. No significant differences were found in the prevalence rates of the degree of collaboration between the two groups (P = 1.000).

Conclusions

No significant differences between prepubertal and pubertal patients were found in the sagittal and vertical dentoskeletal changes with the modified SEC III protocol. Thus, this early Class III treatment produced similar favorable effects in growing subjects regardless of the cervical vertebral maturation stages from CS1 to CS4.

Misdiagnosis and Mismanagement of an Infectious Impacted Canine: A Case Presentation

: Tooth impaction is defined as a partial or complete eruption of a tooth regarding the eruption time. Hereby, we present an infectious canine in a 38-year-old man that primarily presented with chest pain and dyspnea. After two days, he demonstrated a painful swelling and erythema of the face, severe perspiration, nasal congestion, and pleural effusion. The patient was diagnosed with acute bronchitis, mucormycosis, and nasal septum abscess, leading to unnecessary antibiotic therapy and lack of treatment response. After oral and maxillofacial surgery consultation, cone-beam computed tomography (CBCT) revealed an impacted and infectious canine that was surgically extracted. Due to lack of desired response to treatment, he underwent CBCT after oral and maxillofacial surgery consultation. An impacted and infectious canine was detected, which was surgically extracted. Three days later, his symptoms significantly improved, and he was discharged with a stable general condition.

3D Analysis of maxillary incisor root inclinations in cases of unilateral maxillary canine impaction

OBJECTIVES

To evaluate the association between maxillary incisor root inclinations and unilateral canine impaction.

METHODS

A retrospective cross-sectional study of 59 pre-treatment CBCT scans (23 palatal impactions, 10 buccal impactions, and 26 comparison patients). Using Dolphin 3-D Imaging software (Chatsworth, CA), relative incisor angulations to a 3D palatal plane and the shortest distance between the canine crown and the root of the closest lateral incisor were calculated. A one-way analysis of variance was used to determine whether there were any differences between the three independent groups of impactions concerning the four continuous dependent variables incisor root inclination for each maxillary incisor.

RESULTS

Patients with unilaterally impacted maxillary canines demonstrate significant differences in the root inclination position on the ipsilateral (0.0001 > P = 0.002) but not contralateral side. While palatal impactions (PIC) are associated with buccally positioned roots of the ipsilateral lateral (-9.05 degrees) and central incisors (-7.91 degrees), buccal impactions (BIC) are only associated with palatally positioned roots of the ipsilateral lateral incisors (+10.40 degrees) alone. A more labial position of the lateral incisor root was correlated with a more proximally located, coronally positioned, and medially displaced adjacent PIC (0.013 > P < 0.026).

LIMITATIONS

This is a retrospective cross-sectional convenience sample.

CONCLUSIONS

Patients with impacted maxillary canines, whether PIC or BIC, do not show generalized retroclination or proclination of all four maxillary incisor roots. Instead, changes in incisor root inclination were only ipsilateral to the impacted canine. BIC is only associated with palatal displacement of the ipsilateral lateral incisor root, whereas PIC is associated with labial root displacement of both ipsilateral incisors.

Prevalence of Early Childhood Caries in Southern Italy: An Epidemiological Study

The purpose of this study was to assess the prevalence of Early Childhood Caries (ECC) and oral habits among preschool children from a southern Italian cohort. The survey population consisted of 300 subjects randomly selected among children attending two kindergartens in Catania, Italy. The prevalence of ECC and oral habits were clinically evaluated. During the clinical evaluation, the oral hygiene of children was also assessed. Parents were also interviewed using a brief and simple online questionnaire aimed at investigating eating and oral hygiene habits. The selected sample age ranged between 3 and 5 years. The prevalence of ECC was 9.34%, and the most affected teeth were primary molars. Moreover, the prevalence of oral habits was 44.66%. Only two-thirds of the sample brush their teeth at least once per day. The prevalence of ECC among Sicilian children (9.33%) seems suitable with the rest of the country. The results of the present study evidenced that oral habits showed a high prevalence among preschool children. The level of oral hygiene among preschool children is still not sufficient.

Mandibular Coronoid Process Hypertrophy: Diagnosis and 20-Year Follow-Up with CBCT, MRI and EMG Evaluations

Coronoid process hypertrophy (CPH) consists of an abnormal volumetric increment of the mandibular coronoid process; as this process grows gradually, the infratemporal space needed for the rotation and translation of the mandible is reduced, which results in a reduction of the range of mouth opening and lateral excursion, limiting mouth opening. The purpose of this case report was to describe a rare case of hypertrophy of coronoid processes with associated temporomandibular ankylosis, monitored for over 20 years. The patient was first visited when he had a facial trauma at the age of 4. Then he was followed through clinical, functional, instrumental, bi-dimensional and three-dimensional radiological evaluations up to the age of 24. Physical therapy was initiated at the age of 10 to improve the condition of the masticatory muscles, while at the age of 14, Transcutaneous Electrical Nerve Stimulations were performed to reduce muscle tension and, a bite plane was delivered to control the parafunctional activity of the jaw in the night and self-control instruction was provided for daytime habits. The adult patient has not accepted surgical intervention; thus, the future objective is to continue monitoring over the years to avoid a detrimental progression of the medical condition through physical and functional therapies while waiting for patient consent to surgery if needed.