The effect of optimum, indication-specific imaging fields on the radiation exposure from CBCT examinations of impacted maxillary canines and mandibular third molars.

OBJECTIVE: Indication-specific optimum field-of-views (FOVs) have been assessed for CBCT scans of impacted maxillary canines and mandibular third molars, as 40∅ × 35 mm and 35∅ × 35 mm, respectively. The objective was to investigate possible changes in absorbed organs and effective doses, for these two imaging indications, performing CBCT examinations with optimum FOV sizes instead of commonly used FOVs. Additionally, radiation exposure-induced cancer risk was calculated for both imaging indications with optimum FOVs. METHODS: An adult female head phantom (ATOM 702-D, CIRS, Norfolk, VA, USA) was scanned using Planmeca Viso G7 CBCT-device (Planmeca, Helsinki, Finland). Scanning factors, different FOV sizes, dose-area product (DAP) values and anatomical FOV locations were used for Monte Carlo PCXMC-simulation and ImpactMC software. In the PCXMC- simulation, 10-year-old child and 30-year-old adult phantoms were used to estimating effective and absorbed organ doses. RESULTS: The effective dose varied from 58 µSv to 284 µSv for impacted maxillary canines, and from 38 µSv to 122 µSv for mandibular third molars, the lowest dose value for each corresponding to optimum FOV. Effective dose reduction between the optimum FOV and the smallest common FOV of 50∅ × 50 mm, maintaining other scanning factors constant, was 33% for impacted maxillary canines, and 45% for mandibular third molars. At all examinations, the highest absorbed organ doses were in salivary glands or in oral mucosa. CONCLUSIONS: Optimum FOVs, 40∅ × 35 mm for impacted maxillary canine and 35∅ × 35 mm for mandibular third molar, could decrease effective doses received by young patients, and improve radiation safety in these common CBCT imaging procedures.

Maxillary lip dynamics and gingival display revisited: Utilizing standardized metrics.

OBJECTIVE: This study was initiated to validate a predictable system for establishing maximum maxillary lip dynamics and highlight the clinical significance of the findings. MATERIALS AND METHODS: Seventy-five subjects, ranging in age from 25 to 71 years old were photographed with lips in maximum and minimum reveal. The images were digitally analyzed using set references. The statistical analysis was performed using Meta. Numerics version 4.1.4. A Pearson correlation coefficient (r) was carried out to identify relationships between age and maxillary lip dynamics. A p-value less than or equal to 0.05 was considered to be significant. RESULTS: A greater percentage of participants have posterior gingival display than anterior gingival display. There is greater movement of the maxillary lip at the cuspid than at the central incisor. CONCLUSION: There was a tendency for lip dynamics to increase at the right central incisor when there is an increase in lip dynamics at the right cuspid. Lip dynamics does not appear to decrease with age. CLINICAL SIGNIFICANCE: Accurately recording and considering maximum lip dynamics helps avoid asymmetric, excessive or insufficient gingival architecture, insufficient or excessive tooth length and visible restorative margins.

Association between the occurrence of buccally displaced canine and palatal and craniofacial morphology in adolescents.

The main objective of the present research study is to evaluate the association between the occurrence of buccally displaced canine (BDC) and the palatal as well as the craniofacial morphology in adolescents in accordance at the early permanent dentition. As the experimental group, 100 adolescents of Chinese ethnicity (mean age 13.05 years) with crowding and buccally displaced canine (BDC-c) were selected in comparison with the same number of candidates (mean age 12.59 years) without BDC and crowding as control group. Digital dental casts and cephalograms were collected for three dimensional (3D) and cephalometric measurements. An independent sample T-test was used to compare the cephalometric values between the two groups. Logistic regression as commonly statistical methods used in empirical study including categorical dependent variables was used to identify the joint effects of the dental variables' 3D measurements. When comparing the groups with above analysis, patients with BDC showed a statistically significant narrower and higher palatal vault. For the cephalometric variables, the anterior cranial base length, sagittal position of the maxilla (SNA), sagittal position of the mandible (SNB), and skeletal relationship between maxilla and mandible (ANB) appeared to be smaller, whilst palatal plane angle (SN-PP), Frankfort-mandibular plane angle (FMA), anterior facial height, and lower facial height were larger in BDC-c control group (p < 0.05). A smaller inter-first premolar width was significant in the prediction model (p = 0.002). This study highlights that BDC-c participants in early permanent dentition exhibited a narrower dental arch and higher palatal vault, of which a smaller inter-first premolar width would significantly increase the occurrence of BDC.

Dental arch perimeter changes as a result from premature loss of primary anterior teeth due to trauma: A case series in infant and pre-school children.

BACKGROUND: The premature loss of primary anterior teeth in deciduous arches is a controversial topic in the literature, especially due to the lack of robust scientific evidence about the consequences in the arch perimeter space and magnitudes of the effects involved. AIM: Evaluate the association between premature loss of primary anterior teeth and dental arch perimeter changes, according to clinical variables as deciduous arch type, erupted primary canines, midline involvement and deleterious oral habits, on infants and pre-school children. DESIGN: Patients with avulsion or referral to extraction due to traumatic dental injuries (TDI) were evaluated. After the tooth loss, two trained operators measured the tooth/teeth space, both with a digital caliper and a dry tip compass. The clinical documentation included photographs and radiographs. Follow-up visits occurred from the baseline and every two months over a 12-month period. Chi-square test was used to evaluate the association between arch perimeter changes and clinical variables (α = 0.05). A descriptive statistic was performed to explore the magnitude of space changes, with 95% confidence intervals. RESULTS: Eighteen infants/children (mean, 2.78 ± 1.39 years) were included. Nine patients presented space loss (50.0%) (mean, -1.32 mm), six patients gained space (33.3%) (mean, +1.55 mm), and three patients presented space maintenance (16.7%). Clinical variables did not influence dental arch perimeter changes. CONCLUSIONS: Premature loss of primary anterior teeth, as well as deleterious oral habits, deciduous arch type, midline involvement and erupted primary canines, were not associated with dental arch perimeter changes.

Minimum size and positioning of imaging field for CBCT scans of impacted maxillary canines.

OBJECTIVES: In children and adolescents, cone-beam computed tomography (CBCT) is frequently used for localization of unerupted or impacted teeth in the anterior maxilla. CBCT causes a higher radiation dose than conventional intraoral and panoramic imaging. The objective was to analyze the location of impacted canines in a three-dimensional coordinate and thereby optimize the CBCT field-of-view (FOV), for radiation dose reduction. MATERIALS AND METHODS: Location of 50 impacted maxillary canines of children under 17 years was retrospectively evaluated from CBCT scans. The minimum and maximum distances of any part of the right- and left-side canines to three anatomic reference planes were measured to assess the adequate size and position of a cylindrical image volume. RESULTS: A cylinder sized 39.0 (diameter)×33.2 (height) mm, with its top situated 13.8 mm above the hard palate, its medial edge 8.4 mm across the midline, and anterior edge 2.5 mm in front of the labial surface of maxillary central incisors fitted all the analyzed canines. CONCLUSIONS: In this sample, the FOV required for imaging maxillary impacted canines was smaller than the smallest FOV offered by common CBCT devices. We encourage development of indication-specific CBCT imaging programs and aids to facilitate optimum patient positioning. CLINICAL RELEVANCE: An impacted maxillary canine is a common dental problem and a frequent indication for 3D imaging particularly in growing individuals. This article focuses on the optimization of CBCT of impacted canines. Our recommendation of a reduced FOV promotes radiation safety.

Premature loss of primary anterior teeth and its consequences to primary dental arch and speech pattern: A systematic review and meta-analysis.

BACKGROUND: Information about the functional and morphological consequences that occur following the premature loss of anterior teeth is still insufficient. AIM: To evaluate the consequences in children's speech and arch integrity following premature loss of primary anterior teeth compared to those without premature losses. DESIGN: Electronic searches were performed based on the PECO criteria. Observational studies in children (P) who suffered premature loss or extraction of primary anterior teeth (E) compared to children presenting normal occlusion development (C) and the consequences to speech and dental arch perimeter (O) were included. Risk of bias and data extraction were performed. The meta-analysis evaluated the influence of premature loss of primary anterior teeth in articulatory speech disorders (distortion, omission, and substitution) and space loss in the dental arches. Random- and fixed-effect models were used, and heterogeneity was tested. The certainty of evidence was estimated using the GRADE approach. RESULTS: From a total of 2.234 studies, six studies were included in the qualitative synthesis, and four in speech disorders meta-analysis. Despite it was not possible to perform space loss meta-analysis due to the absence of available data, qualitative analysis showed that there was no space loss after premature loss of mandibular primary incisors; a space loss, however, could be observed in children who lost primary canines at an early stage of dental development. For speech disorders results, children who lost anterior tooth presented higher chance of suffering speech distortion, than children without tooth loss (OR 5.466 [1.689, 17.692] P = .005) with low certainty of evidence. On the other hand, there were no statistically differences between premature loss of primary anterior teeth and omission (OR (a) 1.157 [0.439, 3.049] P = .767 and (OR (b) 1.393 [0.434, 4.70] P = .577) or substitution (OR (a) 1.071 [0.581, 1.974] P = .827 and OR (b) 1.218 [0.686, 2.163] P = .5), both with very low certainty of evidence. CONCLUSIONS: Premature loss of primary anterior teeth may affect children phonation causing speech distortion. Consequences of space loss to primary dental arch still need to be further studied. Despite the speech distortion results, included articles present low-level evidence-based quality, thus new studies should be performed.

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

OBJECTIVE: This study aimed to identify radiographic parameters on routine orthopantomograms to aid in early diagnosis of palatally impacted canines. DESIGN: Split-mouth case-control study. SETTING: Single-centre university dental hospital. METHODS: Thirty-three individuals with palatally impacted canines and non-impacted contra-lateral teeth were recruited. Radiographic variables angle A, angle B, angle C, distance D, sector class and depth of vertical impaction were measured for both groups. Mann-Whitney U test and Spearman's correlation coefficient were used to analyse significant differences and association between variables with sector class and depth of vertical impaction, respectively. Logistic regression analysis determined radiographic parameters as predictors of palatal impaction. RESULTS: Significant differences were seen between sector class, depth of vertical impaction and the radiographic parameters between cases and controls ( P ⩽ 0.001). For cases, strong correlation was found for angle C between the impacted canine and occlusal plane (r = -0.28, P = 0.022) and perpendicular distance D of impacted canine to the occlusal plane (r = 0.81, P ⩽ 0.001) with the depth of vertical impaction. Logistic regression analysis showed the odds of canine impaction increase with an increase in angle B and angle C. CONCLUSIONS: Our study showed that greater depth of vertical impaction, sector class, increased perpendicular distance and reduced angulation from occlusal plane resulted in palatal impaction of permanent maxillary canines. The odds of palatal canine impaction increase nearly twofold with every 10 increase in angle B and angle C.

Reliability of different methods for measuring the inclination of the maxillary canines on panoramic radiographs.

OBJECTIVES: To test the reliability of 4 different methods of measuring maxillary canine inclination (CI) on panoramic radiographs, and to determine whether examiner experience level influenced these measurements under ideal experimental conditions. SETTING AND SAMPLE POPULATION: The sample consisted of 20 high-quality panoramic radiographs obtained under standardized conditions using the same radiological apparatus. MATERIAL AND METHODS: Canine inclination (CI) was measured as either the angle formed by the canine long axis and the midline (method A), a line passing through the suborbitary points (method B), the most superior points of condyles (method C) or the mesiobuccal cusp tip of the first molars (method D). Measurements were made at initial observation (T1) and after 3 months (T2) by 5 experienced orthodontists and 5 undergraduate dental students. RESULTS: Mean T1-T2 differences for the measurements were close to zero, with no relationship between their magnitude or direction for each method. Intra-rater reliability was excellent, with the lowest values being observed for method B and the highest for method C. No influence of the examiner experience level was detected. CONCLUSION: The four methods used in this study to measure CI showed excellent intra-rater and inter-rater reliability, irrespective of examiner experience level. Method B was the least reliable and method C the most reliable, if compared with the others.

Influence of the maxillary dimensions and lateral incisor anatomy on the palatal impaction of maxillary permanent canines: A three-dimensional case-control study.

OBJECTIVE: The diagnosis of impacted upper permanent canines (IUPC) is a relatively common clinical finding. The aim of this study was to investigate associations between the upper permanent canines palatal impaction, lateral incisors morphology and the maxilla bone base. MATERIAL AND METHODS: Cone-beam tomography files from 62 subjects were divided into 2 groups: impaction group (ICG/n=31; mean age 14.3±2.4) with 45 canines impacted on the palatal side and age- and sex-matched control group (CG/n=31; mean age 14.3±2.3), with 62 normally erupted canines. Linear and volumetric measurements of the lateral incisors, linear transversal measures and the maxillary anterior perimeter were taken. Independent Student's t-test was used for intergroup analysis with correction of Bonferroni. RESULTS: Significant differences were found for crown length and root diameter (buccal-palatal) (P<0.005). The maxillary anterior perimeter in the ICG was reduced in relation to the GC but not significantly (P=0.008). The transverse skeletal variables of the maxilla were equivalent in the intergroup comparison (P>0.005). CONCLUSION: Smaller dimensions in the crown length and in the upper permanent lateral incisors root buccal-palatal diameter were associated with the impaction of upper permanent canines on the palatal side. The maxillary transverse morphology did not show any association with the occurrence of this condition.

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.

Comparison of Maxillary Canine Retraction Using Split-Mouth Design With Dual Force Cuspid Retractor and T-loop Segmental Arch: A Split-Mouth Randomized Clinical Trial.

Introduction This study was designed to explore the differences between two frictionless mechanics for canine retraction i.e., dual force cuspid retractor and T-loop segmental arch. T-loop for canine retraction creates a biomechanical system to deliver a predetermined force and a relatively constant moment-to-force ratio whereas dual force cuspid retractor uses power arms on buccal as well as palatal aspects for canine retraction. Bodily tooth movement can be achieved by both methods, but in this study, our main focus was to reduce the canine retraction timing with better three-dimensional control. Method This split-mouth study was conducted on a total of 20 cuspids of ten patients (five male and five female). Where one side of the arch was selected for T-loop and the other side for dual force cuspid retractor, randomly. Inclusion criteria for this study were; no congenitally missing teeth (excluding third molar), class I or class II molar relationship, no previous history of orthodontic treatment, good oral periodontal status, patients in whom extraction of maxillary first premolar during treatment was indicated. Both groups were compared for the duration of canine retraction, anchorage loss; tipping, and rotation of cuspid and molar, individually, after retraction. Result The result of this study showed that the duration of canine retraction was significantly less in group one, i.e., dual force cuspid retractor 73.8 ± 12.38 days, than in group two, i.e., T-loop 109.4 ± 16.71 days. The anchorage loss in group one was 0.60 ± 0.61 mm and that in group two was 2.40 ± 0.87 mm. Also, the amount of tipping and rotation of the cuspid and molar individually was significantly lesser in group one than in group two. Conclusion In this study, the dual force cuspid retractor shortens the duration of canine retraction with better three-dimensional control and better anchorage preservation when compared to T-loop.

[Prognosis of impacted canines according to their position in the upper maxillary using different radiographic analyzes]. / Pronóstico de caninos impactados según su posición en el maxilar superior mediante diferentes análisis radiográficos.

Introduction: Canine impaction is an anomaly in which the tooth is prevented from erupting. It occurs when eruption has been delayed and there is radiographic evidence. Objective: To determine the prognosis of impacted canines according to their position in the maxilla by means of different analyses: Ericson & Kurol, Warford and Power & Short; in patients attending private clinics in the city of Asuncion from 2015 to 2020. Methodology: The design is observational descriptive, cross-sectional, using panoramic radiograph measurements. Results: The sample consisted of 37 patients and the 48 canines. It was found that the presence of impacted canines was more frequent in women (69.44%), with unilateral location (70.27%) and palatal position (68.75%). In more than half of the cases the prognosis was unfavorable, however, the concordance was only 75%. There was greater concordance in Warford's prognosis with that of Power & Short (95.91%), while the concordance was lower with that of Ericson & Kurol (81.25%). Conclusion: The frequency of impacted canines in a Paraguayan sample was higher in females, unilaterally located and positioned by palatine. Being unfavorable in more than half of the cases. It is suggested to combine the analyses for projection.

Rare non-syndromic bilateral maxillary and mandibular permanent canine agenesis.

Oligodontia or absence of teeth such as the Canines is rare and is often accompanied with several other missing teeth. This condition may also be accompanied with morphological and growth related changes in the teeth and the maxillofacial complex. Complete agenesis of the permanent canines in the maxilla and the mandible is extremely rare and occurs in association with syndromic oligodontia. Non-syndromic absence of canines however, is extremely rare and has only been reported twice. Studies have shown that the incidence of missing canines is more in females. This report describes a sporadic case of congenital absence of maxillary and mandibular bilateral canines. The patient reported to the clinic with a chief complaint of crowding and wanted alignment. On intra-oral examination it was observed that the patient had all permanent canines missing with no prior history of extractions, crowding in both the arches and class I molars on both sides. With no other symptoms fixed orthodontic therapy was planned for the patient with premolars substituted for the canines.

Dental and Skeletal Age in Patients with Palatally Displaced Canines.

Objective: To determine potential associations between dental and skeletal maturation and palatally displaced canines (PDC) considering gender and chronological age. Material and methods: This study included pretreatment panoramic and lateral cephalometric radiographs of 43 subjects with PDCs and 203 randomly selected orthodontic subjects with normally erupted canines. Both groups were non syndromic patients. Chronological age of subjects was rounded and noted in years with decimal points and compared with chronological age according to Demirjian's dental age assessment. Skeletal maturation was determined by cervical vertebrae changes on cephalometric radiographs. Results: Female subjects with PDC were more affected by left side canine displacement than males (p=0.027) with five times higher odds ratio (OR = 4.9; 95% CIL=1.2-19.7). A comparison of chronologic and skeletal age indicated that PDC subjects were skeletally younger than unaffected groups with statistically significant differences at the age of 10, 12 and 13. (p=0.05). Conclusion: Young subjects with PDCs showed skeletal maturation delay compared to control group, indicating that skeletal maturation assessment could be one of unexplored predicting factors of a PDC, especially at the age between 10 and 13 years in both genders. Subjects with PDC showed intensive growth spurt after the age of 12 years in females, and after the age of 13 in males. Dental maturation delay showed no statistical significance in PDC prediction.

Sella Turcica Abnormalities, Dental Age and Dental Abnormalities in Polish Children.

The frequency of some sella turcica abnormalities on cephalometric radiographs is age related. Chronological age might not overlap with growth; however, no studies could be found on the association between sellar morphology and dental age. Although an association exists between sella turcica bridging and dental abnormalities, no studies have been found correlating sellar abnormalities other than bridging with dental abnormalities. The aim of this study was to find any correlations between sella turcica abnormalities and dental age or dental abnormalities. METHODS: Lateral cephalograms and panoramic radiographs of 206 children aged 6-15 years were analyzed for sela turcica abnormalities, Demirijan dental age, and dental abnormalities. RESULTS: The prevalence of dental abnormalities in patients with sela turcica abnormalities was 16.98%, while in those with normal sella, it was 3%. The differences between dental and chronological age were higher in patients with sella turcica abnormalities (p = 0.002). Dental abnormalities were more prevalent (p = 0.001) in patients with sellar abnormalities other than sellar bridging than in those with sellar bridging or normal sella. CONCLUSIONS: Sella turcica abnormalities are correlated with delayed dental age. Dental abnormalities are more frequent in patients with sellar abnormalities. Dental abnormalities are less frequent in subjects with sellar bridges compared to those with other sellar abnormalities.

Evaluation of facial asymmetry by stereophotogrammetry in individuals with unilateral maxillary impacted canine.

PURPOSE: The aim of this study is to compare the symmetry of the facial and dentoalveolar structures of patients with unilateral impacted maxillary canine teeth with a control group of individuals without impacted teeth using three-dimensional face scans. METHODS: The study included 28 patients (10 females, 18 males) with unilateral impacted maxillary canine teeth and 28 patients (15 females, 13 males) without any impacted maxillary canine between 12 and 25 years of age. The 3dMDface™ (3dMD Inc., Atlanta, GA, USA) imaging system was used to obtain 3D face images. 3dMD Vultus® (3dMD Inc., Atlanta, GA, USA) software was used for the measurements. RESULTS: According to the study findings, there were differences in linear measurements and volume measurements between the right and left sides of the face in patients with an impacted canine. However, these differences were not statistically significant. In patients with an impacted canine, surface differences between the right and left halves of the face were not found to be statistically different from the control group. CONCLUSION: There was no difference in the amount of facial asymmetry between patients with unilateral maxillary impacted canine and patients with normal tooth alignment in the control group.

Implications of impacted mandibular cuspids on mental foramen position.

OBJECTIVE: To determine the horizontal and vertical locations and dimensions of the mental foramen (MF) in digital panoramic images (DPI), and to evaluate the effect of impacted mandibular cuspids (IMC) on the position of the MF. MATERIALS AND METHODS: 715 Digital panoramic images were obtained from the archives of oral radiology clinics of the College of Dentistry, Jouf University. Altogether 236 DPI that met inclusion and exclusion criteria were investigated. One specialist principal investigator examined and analyzed the DPI on a computer screen for horizontal location, average position, and vertical location of the MF. RESULTS: The most common horizontal location of MF with the apices of the teeth in the non-impacted group (NIG) was found to be c = 64.70%, and in the impacted group (IG) d = 47.10%. The average magnitude of MF relative to the apex of second bicuspid in the NIG was found to be 47.10% on the mesial side, and in IG 44.10% on the distal side. The average vertical distance of MF from the lower border of the mandible to the lower border of MF (DLM) in NIG was 14.13 mm (SD ± 1.75 mm), and in IG was 16.85 mm (SD ± 3.06 mm). The average vertical distance of MF from the alveolar crest to the superior border of MF (DAC) in NIG was 6.56 mm (SD ± 2.02 mm), and in IG was 6.67 mm (SD ± 2.28 mm). CONCLUSION: The impacted mandibular cuspid has a definite influence on the location and position of the MF.

Prediction of maxillary canine impaction based on panoramic radiographs.

OBJECTIVES: The objective of this article is to establish a large sample-based prediction model for maxillary canine impaction based on linear and angular measurements on panoramic radiographs and to validate this model. MATERIALS AND METHODS: All patients with at least two panoramic radiographs taken between the ages of 7 and 14 years with an interval of minimum 1 year and maximum 3 years (T1 and T2) were selected from the Department of Oral Health Sciences, University Hospital Leuven database. Linear and angular measurements were performed at T1. From 2361 records, 572 patients with unilateral or bilateral canine impaction were selected at T1. Of those, 306 patients were still untreated at T2 and were used as study sample. To construct the prediction model, logistic regression analysis was used. RESULTS: The parameters analyzed through backward selection procedure were canine to midline angle, canine to first premolar angle, canine cusp to midline distance, canine cusp to maxillary plane distance, sector, quadratic trends for continuous predictors, and all pairwise interactions. The final model was applied to calculate the likelihood of impaction and yielded an area under the curve equal to 0.783 (95% CI [0.742-0.823]). The cut-off point was fixed on 0.342 with a sensitivity of 0.800 and a specificity of 0.598. The cross-validated area under the curve was equal to 0.750 (95% CI [0.700, 0.799]). CONCLUSION: The prediction model based on the above mentioned parameters measured on panoramic radiographs is a valuable tool to decide between early intervention and regular follow-up of impacted canines.

Labially impacted maxillary canines after the closed eruption technique and orthodontic traction: A split-mouth comparison of periodontal recession.

BACKGROUND: Labially impacted maxillary canines may lack periodontal tissue after orthodontic traction. This study evaluated the periodontal status of labially impacted maxillary canines after the closed eruption technique followed by orthodontic traction and investigated pretreatment variables affecting periodontal changes. METHODS: Patients with one labially impacted maxillary canine (impaction group) and one contralateral normal canine (control group) were selected retrospectively. Maxillary canine pretreatment variables (angle, depth, sector, and Nolla stage) were determined from initial panoramic radiography. Periodontal outcomes including sulcus probing depth, bone probing depth, keratinized gingiva width (KGW), attached gingiva width (AGW), clinical crown length (CCL), cemento-enamel junction to alveolar crest (CEJ-AC) distance, root length, and bone support were measured from radiographic and clinical examinations after treatment and compared between the two groups. Pretreatment variables affecting the periodontal outcomes were determined using linear regression analyses. RESULTS: Fifty-four patients (21 males and 33 females; mean age, 12.85 years) were enrolled. The KGW, AGW, and root length were shorter; the CCL and CEJ-AC distance were longer; and the bone support on the interproximal sides was less in the impaction group than in the control group (P < 0.05). The root length was shorter with higher Nolla stages and the distal alveolar crest was lower with deep and mesially angulated impaction (P < 0.01). CONCLUSIONS: After the closed eruption technique, impacted canines exhibited slight but clinically insignificant periodontal recession compared with the contralateral normal tooth. The root developmental stage and pretreatment depth and angle may influence periodontal recession.

Three-dimensional position of impacted maxillary canines: Prevalence, associated pathology and introduction to a new classification system.

Classification of impacted maxillary canines facilitates interdisciplinary communication. Cone beam computed tomography (CBCT) has proven to be superior for the localization of impacted maxillary canines compared with 2D imaging. The purpose of this study was to retrospectively classify a cohort of impacted maxillary canines, using a new developed 3D classification for impacted maxillary canines that is easy to use and does not require complex analysis of the 3D images. A retrospective cohort study was designed, containing CBCT data of 130 patients (male/female: 48/82; median age 16) with a total of 162 impacted maxillary canines. The proposed classification was based on four criteria: vertical crown position, mesiodistal tooth postion, bucco-lingual crown position, and associated pathology. For all included patients, classification criteria were identified and correlated to treatment selection using a newly developed 3D classification. The most common positions were vertical crown position at apical one third of neighboring teeth, mesiodistal tooth angulation, and palatal crown position. The most frequent associated pathologies were dilaceration of the root and resorption of a neighboring tooth. Significant associations among classification variables and treatment options were observed. Limitations of this study are the retrospective design. CBCT enabled 3D assessment of impacted maxillary canines allowing a classification system that may have an impact on further treatment strategies.