Palatally Displaced Canines Research Articles

Relationship between upper lateral incisors anomalies and palatal displaced canine: a case-control retrospective study.

An observational case-control study was designed to retrospectively assess the association among sex, skeletal and dental variables and the and the palatal maxillary canine impaction. The STROBE guidelines were followed. The records of 2195 subjects were analyzed. The data records of subjects with palatally displaced canine (PDC) were compared with the data of randomly selected subjects without PDC. Descriptive statistics, logistic regression model and χ2 test were used. One hundred and one subjects presented at least one PDC; 106 subjects without PDC were randomly selected. From the logistic model, it was found that only gender and persistence of the deciduous canine were significantly associated with PDC. The Chi-square test showed a correlation between the presence of upper lateral incisor anomalies and PDC, otherwise, considering the unilateral impaction, there was no statistically significant difference in the relationship between canine impaction and the presence of the lateral incisor anomalies, on the same or opposite side of the impaction. The female sex and the persistence of maxillary deciduous canines are associated with PDC. The anomalies of the lateral incisor do not seem to play a mechanistic role, but could rather represent a genetic variable of the canine eruption disorder.

Changes in canine inclination after rapid and slow maxillary expansion compared to untreated controls.

Palatally displaced canines (PDC) might represent condition causing several clinical problems, such as roots resorption and malocclusion, and can develop palatal canine impaction. Some interceptive treatments such as rapid maxillary expansion were suggested in order to foster maxillary canine eruption. Among expansion protocols, no data are available about differences between rapid and slow maxillary expansion on maxillary canine eruption. The aim of this study was therefore to evaluate α-angle changes in palatally displaced canines using rapid and slow maxillary expansion compared to untreated control patients. The final sample comprised 19 patients treated with rapid maxillary expansion (RME group), 17 treated with slow maxillary expansion (SME group) and 22 control patients (Control group). α-angle was measured on panoramic films to detect canine inclination at the beginning, and at the end of maxillary expansion treatment or observation, time and changes over time were compared. In the comparisons among groups, RME group was the only group showing a decrease in α-angle measurements that was statistically significant also when compared to the other groups, except for the left side when compared to SME group. RME treatment significantly and positively affected canine position when compared to SME treatment and control group.

Incisor root resorption associated with palatally displaced maxillary canines: Analysis and prediction using discriminant function analysis

Incisor root resorption associated with palatally displaced canine (PDC-IRR) is an important phenomenon that might alter the orthodontic treatment plan. The aims of this study were to investigate the prevalence and characteristics of PDC-IRRs, to compare PDC-IRR and PDC-No-IRR groups, to identify predictors for PDC-IRR, and to produce a valid PDC-IRR prediction model using discriminant function analysis. Cone-beam computed tomography images for 107 palatally displaced canines (PDCs) and 51 fully erupted nondisplaced canines (NDC) were analyzed for the presence of incisor root resorption (IRR). The PDCs were divided into 2 groups: PDC-IRR (52 canines) and PDC-No-IRR (55 canines). The 3 groups were compared, and the following variables were measured: canine follicle size, contact with adjacent incisors, associated dental abnormalities, sector analysis, canine vertical relation to adjacent root, lateral incisor angulation and inclination, canine angulation and distance to reference planes (dental midline, midpalatal suture, occlusal plane, pterygoid vertical plane, and lateral incisor), and space available for canine in the dental arch. Discriminant functional analysis was used to produce a discriminant function equation to predict PDC-IRR. Root resorption affected 74% of lateral incisors adjacent to PDCs and 25.5% of lateral incisors adjacent to NDCs. IRR was located lingually in 41% of PDCs and in the mid and apical thirds in 89%. In the PDC-IRR group, 94.2% of canines were in contact with adjacent roots compared with 23.6% in the PDC-No-IRR group (P<0.001). Canine follicle size was>2mm in 42% of PDC subjects. Overall mean value of follicle width in PDC canines was 1.79±1.06mm. Peg-shaped lateral incisors were recorded in 19% of PDC subjects compared with 4% in NDCs (P=0.012). The stepwise analysis using cone-beam computed tomography records produced a discriminant function based on 3 variables. The analysis correctly predicted the outcome in 83% of subjects. The variables contributing to the prediction equation were canine contact with adjacent incisors, size of canine dental follicle, and the presence of peg-shaped lateral incisor. Canines in contact with adjacent incisor roots was the only risk factor detected for PDC-IRR. Very good predictive discrimination (83%) emerged for PDC-IRR subjects. Predictors of PDC-IRR were canine contact with adjacent incisor, size of canine dental follicle, and presence of peg-shaped lateral incisor.

Effectiveness of various interceptive treatments on palatally displaced canine–a systematic review

The aim of this systematic review was to assess whether interceptive treatment carried out in the mixed dentition period improves the position of Palatally Displaced Canines (PDC). A systematic search was performed on various computerized databases. A hand search was also performed by reviewing the references within the examined studies and titles of the papers published over the last 30 years on various orthodontic journals. This systematic review analysed eight articles, of which five were Randomized Clinical Trials (RCT) and three were prospective control studies. Qualitative assessment was done for all the eight studies. The effect of interceptive measures such as extraction of primary canine, Rapid Maxillary Expansion (RME), cervical pull headgear and Transpalatal Arch (TPA) on successful eruption of Palatally Displaced Canines was analyzed. Interceptive treatment improves the position of PDC and reduces the chances of impaction. Significant changes in success rate depend on diagnosis at early mixed dentition stage. A combination of interceptive measures which includes extraction of primary canine, cervical pull headgear, TPA and RME aided in successful eruption. However, Randomized clinical trials with increased sample size, proper randomization comparing all the interceptive measures along with assessment of other factors such as patient satisfaction, pain experience and cost factor will yield more evidence based conclusions.

Authors' response

Thank you for the interest in our article. We agree with the comment that cone-beam computed tomographic (CBCT) imaging provides more accurate information and we never contradicted that fact. Radiation dosage with the use of x-rays should benefit the patient and simultaneously provide the dentist with accurate information, which is the reason for principles such as ALARA (as low as reasonably achievable) turning to ALADA (as low as diagnostically acceptable).1Jaju P.P. Jaju S.P. Cone-beam computed tomography: Time to move from ALARA to ALADA.Imaging Sci Dent. 2015; 45: 263-265Google Scholar The purpose of our study was to examine to what extent angulation and sector position in palatally displaced canines (PDCs) differed between the panoramic radiograph and the CBCT image. We found that angulation and sector position deviated, but clinically the differences were modest. Overlap in frontal view to determine the sector position and angulation of PDC to midline was not hard to pin down in the panoramic radiographs, and these references have been used widely in the literature on interceptive treatment of PDCs. The lateral incisors near the PDC do not always have shorter roots.2Brin I. Becker A. Shalhav M. Position of the maxillary permanent canine in relation to anomalous or missing lateral incisors: a population study.Eur J Orthod. 1986; 8: 12-16Google Scholar The main conclusion to draw from the article is that CBCT should not be used routinely for diagnosis of PDC. The decision making regarding interceptive extraction of deciduous canines in PDC cases could be undertaken with the use of panoramic radiographs at an early age, around 10-11 years.3Bazargani F. Magnuson A. Lennartsson B. Effect of interceptive extraction of deciduous canine on palatally displaced maxillary canine: a prospective randomized controlled study.Angle Orthod. 2014; 84: 3-10Google Scholar There are cases, however, where CBCT is indicated, for example, if there is suspicion of root resorption or lesions that could result in a change of therapy. Despite the shortcomings of a panoramic radiograph, it is a diagnostic tool that could be considered good enough for rendering PDC position when CBCT is not crucial for treatment planning, in line with the principle of ALADA. Accord between cone-beam computed tomographic images and panoramic radiographsAmerican Journal of Orthodontics and Dentofacial OrthopedicsVol. 155Issue 6PreviewI read the article “Are panoramic radiographs good enough to render correct angle and sector position in palatally displaced canines?” in the March issue (Björksved M, Magnuson A, Bazargani SM, Lindsten R, Bazargani F. Am J Orthod Dentofacial Orthop 2019;155:380-7). I appreciate and congratulate the authors for their profound and immense contribution in highlighting the sector analysis for palatally displaced canines (PDCs) in panoramic imaging and comparing that with cone-beam computed tomographic (CBCT) scans. Full-Text PDF

Are panoramic radiographs good enough to render correct angle and sector position in palatally displaced canines?

The early interceptive treatment of palatally displaced canines (PDCs) has for decades been based on their position in panoramic radiographs. In the 1990s, cone-beam computed tomography (CBCT) started to become popular in cases with PDCs. The aims of this prospective study were to evaluate the agreement of PDC sector position and angle to midline between panoramic radiographs and CBCT scans. PDC sector and angle to midline were measured in panoramic radiographs and CBCT scans in 58 consecutive patients with 64 PDCs. Kappa with linear weighting was used to assess the agreement between the measurements of PDC sector position and Bland-Altman limits of agreement to assess the agreement between the PDC angular measurements in the 2 methods. PDC sector position and angle to midline had systematically higher values in panoramic radiographs compared with those in the CBCT scans. The agreement of sector position between the methods was fair: weighted kappa 0.36 (95% CI 0.24-0.49). The mean difference in angle was almost 7° (95% CI 5.9°-7.9°) higher in panoramic radiographs compared with CBCT. Panoramic radiographs overestimate PDC sector and angle to midline position, compared with the use of CBCT scans, but clinically the differences are quite modest. Panoramic radiographs could be considered good enough for rendering PDC position when the need for 3D information is not crucial for treatment planning.

Morphology of maxilla in patients with palatally displaced canines

The aim of this study was to investigate the possible relationship between the morphology of maxilla and the palatally displaced canines (PDC). In this cross-sectional study, there were 101 patients (45 males, 56 females) aged 12 to 16years, referred to Hamadan school of dentistry in 2014. They were divided into 3 groups: the bilateral PDC (PDCb) group (male=15, female=21), the unilateral PDC (PDCu) group (male=16, female=19), and the control group (male=14, female=16). Five morphology related variables including intermolar width, maxillary arch length, palatal vault depth, palatal intermolar area, and nasal width were measured using CBCT images with Dolphin Imaging software, version 11.5. Statistical analysis was performed with ANOVA and the Dunnett test using SPSS software, version 16.0. Only the palatal intermolar area and the palatal vault depth values were significantly less in the PDCu and the PDCb groups than those in the control group (the palatal intermolar area: 376.17, 381.93, and 423.75mm2, the palatal vault depth: 13.19, 13.42, and 14.59mm; respectively; P<0.05). For all the variables, there was no statistically significant difference between the PDCu and PDCb groups. Decreased palatal vault depth and palatal intermolar area may be correlated with greater chance of palatal displacement of canines. Future prospective studies in mixed dentition patients are needed as a predictive factor to find the probability of PDC.

Effects of impaction severity of treated palatally displaced canines on periodontal outcomes: a retrospective study

BackgroundEven though periodontal health was suggested to be not related to the traction technique, some other variables might influence the esthetic outcome of palatally displaced canines (PDC) when aligned, such as the initial position and impaction rate of the canine before treatment. The purpose of the present study was therefore to evaluate the existing correlations between periodontal health outcome of PDC after their exposure and alignment and their initial position identified according to the different rates of impaction severity.Materials and methodsThe final sample enrolled 293 PDC which satisfied inclusion and exclusion criteria. All the canines were exposed using CT by the same oral surgeon and orthodontic traction was applied using the easy cuspid device followed by fixed appliance treatment. Image analysis and periodontal status evaluation were performed for all PDCs.Resultsα-Angle and d-distance showed no significant differences in the periodontal outcome of PDCs after treatment. The only tested variable showing significant differences was S, since canines with CEJ visible at the end of the treatment presented sectors with a mean score of 1.67, which was significantly different (P < 0.05) when compared to the S-sector for the canines that showed PD < 2 mm at the end of the treatment.ConclusionsRadiographic variables as α-Angle and d-distance seem to not influence the periodontal outcome of the treated impacted canine regardless of the amount of gravity. On the contrary, S-sector might play a significant role when higher rates of gravity are present suggesting the possibility in few cases for periodontal damage at the end of treatment.

Third molar tooth agenesis and pattern of impaction in patients with palatally displaced canines.

To investigate the association between third molar agenesis and pattern of impaction, missing teeth, and peg-shaped lateral incisor with palatal canine displacement (PDC). The pretreatment orthodontic orthopantomograms of 438 patients (122 males and 316 females) diagnosed with PDC were included. A total of 338 patients with normally erupted canines who had a preexisting radiograph as part of their orthodontic treatment (125 males and 313 females) served as controls. Orthopantomograms were evaluated for missing third molars, third molar eruption status, and type of impaction, third molar spaces, third molar width, and angulation. In the PDC group, at least one third molar was missing in 48% and 19% in the upper and lower arches, respectively. Also, 38% and 67% of PDC patients had at least one third molar impaction in the upper and lower arches, respectively. The difference between the PDC and control groups was significant for both missing and impacted third molars ( P < .001 for each). The most common type of third molar impaction in the upper arch was vertical and distoangular in the PDC and control groups, respectively. Upper and lower third molar width and spaces were reduced in PDC patients when compared with the control group ( P < .001). In PDC patients, missing teeth and peg-shaped lateral incisors were recorded in 5.6% and 9.1%, respectively. PDC patients showed a high prevalence of third molar agenesis and impaction. Upper and lower third molar width and space were reduced in the PDC patients. There were no significant associations between tooth agenesis (other than third molars) and the PDC anomaly.

Closed vs open surgical exposure of palatally displaced canines: surgery time, postoperative complications, and patients' perceptions: a multicentre, randomized, controlled trial.

Closed and open surgical techniques are two different main approaches to surgical exposure of palatally displaced canines (PDCs). Because there is insufficient evidence to support one technique over the other, there is a need for randomized controlled trials. To compare surgery time, complications and patients' perceptions between closed and open surgical techniques in PDCs. The trial was a multicentre, randomized, controlled trial with two parallel groups randomly allocated in a 1:1 ratio. Study participants were 119 consecutive patients from 3 orthodontic centres, with PDCs planned for surgical exposure, randomly allocated according to a computer-generated randomization list, using concealed allocation. Full-thickness mucoperiosteal flap was raised, and bone covering the canine was removed in both interventions. In closed exposure, an attachment with a chain was bonded to the canine and the flap was sutured back with the chain penetrating the mucosa. In open exposure, a window of tissue around the tooth was removed and glass ionomer cement placed on the canine crown, to prevent gingival overgrowth during spontaneous eruption. Patient perceptions were assessed with two questionnaires, for the evening on the day of operation and 7 days post-surgery. It was not possible to blind either patients or care providers to the interventions. The outcome assessors were blinded and were unaware of patients' intervention group. Seventy-five girls and 44 boys, mean age 13.4 years (SD 1.46) participated in the study and got either of the interventions (closed exposure, n = 60; open exposure, n = 59). Surgery time did not differ significantly between the interventions. Complications though were more severe in bilateral cases and the patients experienced more pain and impairment in the open group. There were no statistically significant differences regarding surgery time between the groups. Postoperative complications were similar between the groups in unilateral PDCs, but more common in the open group in bilateral cases. More patients in the open group experienced pain and impairment compared to the closed group. Trial registration: ClinicalTrials.gov, ID: NCT02186548 and Researchweb.org, ID: 127201.

Morphology of palatally displaced canines and adjacent teeth, a 3-D evaluation from cone-beam computed tomographic images

BackgroundThe goal of this study was to investigate in patients with unilateral palatally displaced canine (PDC) the morphology of maxillary teeth from cone-beam computed tomography (CBCT) scans both on the PDC side and non-PDC side using a “surface matching” technique.MethodsCBCT images from 28 patients (mean age 16.04 ± 1.77 years) with unilateral PDC were selected. Each tooth in this study was segmented and then rendered into a 3D model using Mimics Research software and the root length was measured. Afterwards, 3D deviation analysis between the PDC and non-PDC side was carried out using Geomagic Control X software.ResultsStatistically significant differences (p ≤ 0.001) were obtained when comparing the root lengths and volumes of lateral incisors from the PDC side, non-PDC side and control group. In accordance with the findings of 3D deviation analysis, statistically significant differences between the patients and control group were obtained for the lateral incisors and canines (p ≤ 0.0001) and greater differences were found for the tooth crowns and root tips.ConclusionsLateral incisors adjacent to PDCs have shorter roots than contra-lateral lateral incisors. Furthermore, there were morphological differences between lateral incisors and canines in subjects with unilateral PDCs.

Association between maxillary lateral incisors' root volume and palatally displaced canines: An instrumental variables approach to the guidance theory.

To evaluate association and causation between maxillary lateral incisors' (MxI2) apical root volume (ARV) and palatally displaced canines (PDC). In a retrospective cross-sectional study, computed tomography scans of 179 patients with unilateral PDC were analyzed. MxI2 root length and volume on the impaction and eruption side were measured. A mixed logit model was used to infer the association between ARV and PDC and an instrumental variables approach to interpret causality. MxI2 root length on the impaction side was shorter in 42%, equal in 33% and longer in 25% of the patients. ARV amounted for 13.5% of total root volume on the impaction and 14.9% on the eruption side. Reduced ARV was significantly associated with the impaction side ( P < .001). The causal effect of ARV on PDC in the instrumental variable approach amounted to less than half of the association in a standard noncausal approach. An association between PDC and reduced MxI2 root length and volume was confirmed. However, the lack of causality did not allow the researchers to draw a conclusion as to whether a reduced ARV is causing PDC or resulting from it; this should be considered in etiologic theories.

The use of panoramic radiographs to decide when interceptive extraction is beneficial in children with palatally displaced canines based on a randomized clinical trial.

To evaluate which palatally displaced canines (PDCs) benefit from interceptive extraction of the deciduous canine, to assess possible side effects from the extraction, and to analyse other dental deviations in patients with PDCs. A sample of 67 patients (40 girls, mean age: 11.3 ± 1.1; 27 boys, mean age ± SD: 11.4 ± 0.9) with unilateral (45) or bilateral (22) PDCs were consecutively recruited and randomly allocated to extraction or non-extraction using block randomization. No patients dropped out after randomization or during the study. The patients were given a clinical examination and panoramic radiographs were taken at baseline and after 6 (T1) and 12 months (T2). An individual therapy plan was made for the PDCs that had not erupted at T2. Measurements were performed blindly and the outcome measures were: canine position and angulation, root development, midline shift, rotation, or movement of adjacent teeth into the extraction site, and frequency of other dental deviations. Interceptive deciduous canine extraction is beneficial if the alpha angle is between 20 and 30 degrees. A PDC located in sector 4 with an alpha angle >30 degrees should have immediate surgical exposure, while canines angulated less than 20 degrees and located in sector 2 can be observed without prior interceptive extraction. Deciduous canine extraction was more beneficial in younger patients with less advanced root development. Minor side effects, such as rotation or migration of teeth into the extraction space, were observed in 15 out of 35 patients. A majority of the patients had other dental deviations than PDC in the dentition. The results are only valid for patients with no space deficiency in the maxilla and with PDCs located in sector 2-4. No harms were detected. The alpha angle and sector position are good diagnostic predictors of when interceptive extraction is beneficial. Minor side effects are seen after the extraction and the majority of the patients had other dental deviations too. This trial was registered at http://www.fou.nu/is/sverige, registration number: 211141.

Treatment decision analysis for palatally-displaced canines based on orthodontists’ opinion and CBCT

The aim of this study was to assess difficulty of treatment of palatally-displaced canines (PDC) according to experts' opinion using CBCT data and to determine a cut-off point for extraction versus forced eruption. Seven CBCT variables of thirty PDC cases were measured with Dolphin 3D software. In addition to measurements of each case, nine 3D and 2D views were prepared on one page and uploaded on the website (canineimpaction.com). Thirty-four orthodontists were asked to judge the difficulty of bringing the impacted canine into occlusal plane. Then, they scored from 1 to 5 the effect of each variable on treatment difficulty and also decided whether to force-erupt or extract the impacted tooth. Overlap in frontal view, angulation of the canine to the occlusal plan, vertical distance to the occlusal plane, age, dilaceration and rotation had significant relationship with the level of treatment difficulty. The treatment plan decision for PDC with treatment difficulty>7.5 was extraction rather than forced eruption. We can predict treatment difficulty of PDC by measuring CBCT variables and decide to extract or force-erupt with a reasonable level of agreement among a panel of orthodontists.

DENTOSKELETAL PARAMETERS IN INDIVIDUALS WITH MAXILLARY CANINE DISPLACEMENT (A RETROSPECTIVE STUDY)

No studies have been done to measure the skeletal, dentoalveolar and soft tissue parameters in subjects with palatally and buccally displaced canines. The hypothesis of this study is that there is difference in the skeletal and dentoalveolar measurements between subjects with palatally, buccally and normally erupting canines. A total of 200 subjects with maxillary canine displacement (90 palatally displaced, 110 buccally displaced) were recruited for this study. The age of the subjects ranged between 13-15 years old. Subjects were divided into 2 groups (maxillary palatal canine displacement and maxillary buccal canine displacement). These subjects were compared with 100 subjects asa control group. In conclusion,There in is no significant difference in maxillary length between subjects with buccally and palatally displaced canine and control group. However palatal canine displacement group had reduced vertical dimensions, increased overbite, small dentoalveolar heights and retruded upper and lower lips.

Associations among sella turcica bridging, atlas arcuate foramen (ponticulus posticus) development, atlas posterior arch deficiency, and the occurrence of palatally displaced canine impaction.

Head and neck skeletal anomalies or normal variants might predict the occurrence of palatally displaced impacted maxillary canines. Despite their clinical importance, studies in this regard are rare, especially when it comes to vertebral anomalies. This case-control study was performed on cephalographs of 35 orthodontic patients (11 male, 24 female) with palatally displaced canines (PDC) and 75 patients without them (29 male, 46 female). PDC were diagnosed on panoramic and lateral cephalographs and from clinical reports. The occurrence and severity of sella turcica bridge and the atlas ponticulus posticus, and deficiency of the posterior atlas arch were evaluated twice on lateral cephalographs. The associations between the occurrence and level of these skeletal anomalies and variations of PDC occurrence as well as additional correlations were assessed using multivariable and bivariate statistics (α=0.05; β≤0.2). The patients' mean age was 18.4±1.9years. In the control and patient groups, 23 (30.7%) and 21 subjects (60%) had sella turcica bridging, respectively (chi-square, P=0.003). Ponticulus posticus was observed in 14 (18.7%) controls and 15 (42.9%) patients (chi-square, P=0.007). Posterior atlas arch deficiency was observed in 4 (5.3%) controls and 5 (14.3%) patients (chi-square, P=0.111). The presence of ponticulus posticus and sella turcica bridging might be associated with increased odds of PDC occurrence for about odds ratios of 3.1 and 3.5 times, respectively (binary logistic regression). PDC is positively associated with the occurrence and severity of sella turcica bridging and ponticulus posticus. The association between PDC and posterior atlas arch deficiency was inconclusive.

Associations between occlusion, jaw relationships, craniofacial dimensions and the occurrence of palatally-displaced canines.

Cephalometric and arch measurements might predict the occurrence of a palatally-displaced impacted maxillary canine (PDC). Despite their clinical importance, studies in this regard are limited and controversial. In this case-control study, 35 PDC patients and 77 controls aged over 13 years were examined. Eleven cephalometric measurements: N-S, ANS-PNS, ANS-N, S-N-ANS, facial angle (FH/NPog), SNA, SNB, Y-axis (SN/SGn), gonial angle, Go-Gn/SN, and Jarabak Index were performed. The maxillary and mandibular intermolar and interpremolar widths were measured. Patients' sagittal skeletal relationships and centric occlusions (molar) were measured by radiographic and cast examinations. The differences between the two groups in terms of the above-mentioned cephalometric and anatomic variables were assessed using Chi2 and Mann-Whitney U-tests (α=0.05). Chi2 showed a significant negative association between dentoalveolar class I (molar) and PDC occurrence (P=0.018), but not between PDC and skeletal sagittal relationships. Facial angle (FH/NPog) and Y-axis (SN/SGn) were more obtuse in patients with PDC (P<0.05). No arch dimensions differed between the two groups. PDC tends to accompany molar class II/III but is not associated with upper or lower jaw widths or lengths. Vertical dimensions might be smaller in PDC patients. Some variables were inconclusive and need future assessments.

"Maxillary lateral incisor partial anodontia sequence": a clinical entity with epigenetic origin.

ABSTRACTThe relationship between maxillary lateral incisor anodontia and the palatal displacement of unerupted maxillary canines cannot be considered as a multiple tooth abnormality with defined genetic etiology in order to be regarded as a “syndrome”. Neither were the involved genes identified and located in the human genome, nor was it presumed on which chromosome the responsible gene would be located. The palatal maxillary canine displacement in cases of partial anodontia of the maxillary lateral incisor is potentially associated with environmental changes caused by its absence in its place of formation and eruption, which would characterize an epigenetic etiology. The lack of the maxillary lateral incisor in the canine region means removing one of the reference guides for the eruptive trajectory of the maxillary canine, which would therefore, not erupt and /or impact on the palate. Consequently, and in sequence, it would lead to malocclusion, maxillary atresia, transposition, prolonged retention of the deciduous canine and resorption in the neighboring teeth. Thus, we can say that we are dealing with a set of anomalies and multiple sequential changes known as sequential development anomalies or, simply, sequence. Once the epigenetics and sequential condition is accepted for this clinical picture, it could be called “Maxillary Lateral Incisor Partial Anodontia Sequence.”

A retrospective analysis of maxillary tooth size variation in dentitions with palatal canine displacement among northern Indian female population

A retrospective analysis of maxillary tooth size variation in dentitions with palatal canine displacement among northern Indian female population

Extraction of the deciduous canine as an interceptive treatment in children with palatally displaced canines - part II: possible predictors of success and cut-off points for a spontaneous eruption.

To analyse factors affecting the success rate of palatally displaced canines (PDCs) and eruption time and to find cut-off points to predict when interceptive extraction is beneficial versus unnecessary. Sixty-seven patients, 40 girls, 27 boys (10-13 years) with uni- (45) or bilateral (22) PDCs, persisting deciduous canine and no previous orthodontic treatment were randomly allocated for extraction or non-extraction using the block randomization method. There were no dropped out after the randomization or during the trial. Clinical examination and cone beam computed tomography was performed at 0, 6, and 12 months. Blinded measurements were done on baseline images. Erupted PDCs had a significantly smaller mesioangular angle, shorter distance of canine cusp tip-dental arch plane, and larger distance of canine cusp tip-midline, and the patients were younger compared to the non-erupted group. Faster eruption was noted of PDCs in the extraction group. Spontaneous eruption was achieved without prior deciduous canine extraction with cut-off points: initial canine cusp tip-midline of 11mm, canine cusp tip-dental arch plane of 2.5mm, or a mesioangular angle of 103 degrees. PDCs with a less favourable position, i.e. an initial cusp tip-midline of 6mm, a canine cusp tip-dental arch plane of 5mm, or a mesioangular angle of 116 degrees, will need surgical exposure despite interceptive extraction of the deciduous canine. The canine cusp tip-midline had the best predictive measure for assessing the outcome. Decision on where to place the cut-off points may differ from one operator to another, therefore results from several studies are needed to get average cut-off points. Deciduous canine extraction is the variable that affects the spontaneous eruption of the canine most. Canine cusp tip-midline, canine cusp tip-dental arch plane, and mesioangular angle might be useful for distinguishing when an interceptive extraction of the deciduous canine is beneficial or when exposure of the PDC should be implemented without previous interceptive treatment. This trial was registered in 'FoU i Sverige' (http://www.fou.nu/is/sverige), registration number: 40921. The protocol was not published before trial commencement.