The effect of the dental follicle volume of palatally impacted canines on the relative position of the adjacent teeth.

OBJECTIVE: To assess if the dental follicle volume of palatally impacted canines (PICs) affects the relative root position of the adjacent lateral incisors (LIs) and first premolars (FPs). MATERIALS AND METHODS: A retrospective cross-sectional study of 49 patients with unilaterally PICs with dental follicles who had CBCT imaging previously taken. Four orthodontic centers in different countries provided the sample. A mean difference of 5° between the angular measurements (mesiodistal tip, buccolingual inclination, or mesiodistal rotation) of the LI and FP adjacent to the PIC and the controls was considered clinically relevant. A value of 0.05 was set for significance level and a power of 80%. The minimum sample size was determined to be 26 patients. These patients were further assigned to an LI sample (n = 49) and an FP sample (n = 23), dependent on the direct contact of the dental follicle to that adjacent tooth. A manual segmentation technique was used to obtain the volumetric measurements of the dental follicle. Angular measurements of adjacent teeth were then compared to the contralateral nonimpacted side, which acted as the control. A multivariant regression analysis was performed using IBM SPSS software, and statistical significance was set at α = 0.05. RESULTS: Adequate intra-rater reliability was accomplished. The multivariant regression analysis implied that there is no difference in the mean change in the tip, torque, and rotation of the LI and FP between the impacted and control sides when dental follicle volumes are considered (P = .509 for the LI sample and P = .804 for the FP sample). LIMITATIONS: CBCT imaging of dental follicle border delimitations, partial volume effect, and scattering are limitations. This is a convenience sample where the FP subsample is small. CONCLUSION: The dental follicle volume of the PICs does not seem to influence the relative position of the adjacent LI and FP mesiodistal tip, buccolingual inclination, and mesiodistal rotation. Early intervention could have been suggested to avoid certain malocclusion traits if significant displacements were demonstrated.

Salivary levels of Osteoprotegerin and receptor activator of nuclear factor-kappa ligand during orthodontic tooth movement-A prospective pilot study.

OBJECTIVES: The aim of this study was to monitor changes in Osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa ligand (RANKL) levels in the saliva during orthodontic tooth movement (OTM). MATERIALS AND METHODS: Nine healthy females (15-20 y of age) with four pre-molar extractions and fixed appliance were included. In total, 134 stimulated and 134 unstimulated saliva samples were collected: at baseline and then every 6-8 weeks at follow-up appointments during the whole orthodontic treatment. Twelve age-matched females with no active orthodontic treatment served as a control group. Saliva samples were analysed by enzyme-linked immunosorbent assay (Elisa). The mean levels of OPG and RANKL were calculated according to the different orthodontic treatment stages: alignment, space closure and finishing. A mixed model analysis was used to compare the means of treatment stages. Baseline OPG levels were compared with the control group using an independent t-test. OPG levels were measured in stimulated saliva due to low levels in unstimulated saliva. RESULTS: No significant difference was observed between baseline OPG values and the control group. OPG increased significantly at all treatment stages: alignment, space closure and finishing compared with baseline (P = 0.002, P = 0.039, P ≤ 0.001, respectively). The salivary levels of OPG increased gradually, except during space closure, reaching peak levels at finishing. RANKL was undetectable in stimulated and unstimulated saliva by sandwich Elisa during OTM. CONCLUSIONS: This novel approach shows the changes in the levels of OPG in OTM and indicates how and when to sample saliva during orthodontic treatment to analyse bone remodelling.

Implant-supported crowns on maxillary laterals and canines-a long-term follow-up of aesthetics and function.

OBJECTIVES: To assess the long-term aesthetic and functional aspects of implant-supported crowns in lateral (ISC-L) and canine positions (ISC-C). MATERIALS AND METHODS: Thirty-two patients (14 males, 18 females, mean age: 23.1, SD:2.0) with an ISC-L or ISC-C participated in this prospective cohort study at baseline (T0) and in the long-term follow-up (T1, mean years: 11.1, SD: 1.0). Twenty-four patients (11 males, 13 females) participated in T1. Patient-reported outcomes (PROM) were rated using surveys with questions related to aesthetics and function. The colour of the implant crown and the buccal gingiva, the appearance of the papilla, periodontal health and temporomandibular disorder (TMD) outcomes were assessed in a clinical examination. The Mann-Whitney, Chi-square and Signed Rank tests were performed. RESULTS: Patients with an ISC-L and ISC-C were equally satisfied with the crown shape and colour at T0 and T1. No differences in TMD outcomes were reported by the patients and no clinical signs of TMD were observed. At T1, ISC-C had more bleeding on probing and a three mm greater pocket depth than ISC-L (p = 0.03, p = 0.01, respectively). At T0, operators graded the crown colour of ISC-L as being too dark (35%) and ISC-C as being too light (40%). At T1, no difference was seen between the two groups regarding crown colour, gingiva colour and the papilla (p = 0.2749, p = 0.2099, p = 0.8053, respectively). CONCLUSIONS: The PROM and clinical examination show that ISC-L and ISC-C are equivalent with regard to aesthetics and function in the long term. CLINICAL RELEVANCE: Although ISC-L and ISC-C are aesthetically and functionally comparable in the long term, ISC-Cs are more likely to impact periodontal health.

Failure frequency of fixed mandibular retainers after pre-treatment of the enamel surface with pumice versus sandblasting-a randomized controlled trial.

BACKGROUND/OBJECTIVES: To compare retainer survival, periodontal health, and caries implications of fixed lower retainers bonded after pre-treatment of the enamel surface with either pumice or sandblasting. TRIAL DESIGN: Two-arm parallel-group, two-center randomized controlled clinical trial. METHODS: One hundred sixty patients (101 females, 59 males, mean age: 17.9) requiring mandibular retainers were consecutively recruited. Patients were randomly allocated to have pre-treatment of the enamel surface with either pumice (n = 80) or sandblasting (n = 80). The primary outcome was retainer survival at 3 (T1) and 12 months (T2) control. Secondary outcomes were carious lesions and periodontal health: plaque index (PI), gingival index (GI), calculus index (CI), and probing depth (PD). The randomization sequence was generated using an online randomization and allocation concealment was secured by contacting the sequence generator for treatment assignment. Blinding was not possible at T0 due to the nature of the intervention. Statistical analyses were carried out using the t-test, Fisher's exact test, repeated measure analysis of variance, and log rank test. RESULTS: Overall, the risk of bonding failure at T1 was 6.7 per cent and at T2 6.9 per cent. There were no statistically significant differences in failure rate between the two groups, neither at T1 (P = 1.000) nor at T2 (P = 0.360). No statistically significant differences were found for the intercanine periodontal indices GI, PI, CI, PD, and caries between the two groups at T0 and T1. At T2, significantly more gingivitis and plaque were seen in the sandblasting group (P = 0.05 and P = 0.047, respectively) compared with the pumice group. Calculus increased during the follow-up period in both groups (P ≤ 0.001) as well as plaque levels (P ≤ 0.001 and P = 0.025, respectively). No harm was reported. CONCLUSIONS: Enamel sandblasting prior to bonding mandibular retainers is not better at preventing bonding failure. REGISTRATION: 275767 (https://www.researchweb.org/is/sverige).

Did the coronavirus disease 2019 pandemic affect orthodontic treatment outcomes? A clinical evaluation using the objective grading system and Peer Assessment Rating index.

INTRODUCTION: This study aimed to compare the treatment outcome of patients whose orthodontic treatment was completed before or during the coronavirus disease 2019 pandemic. METHODS: Pretreatment and posttreatment models of 100 patients treated with fixed orthodontic appliances were evaluated using the peer assessment rating (PAR) index. Posttreatment models and panoramic radiographs were measured and scored with the objective grading system (OGS). All patients had their treatment plans before the coronavirus disease 2019 pandemic, but the orthodontic treatment finishing date was before (prepandemic: group 1, n = 50) or during (pandemic: group 2, n = 50) the pandemic. Intergroup comparisons were tested with an independent samples t test or Mann-Whitney U test. Chi-square test statistics and Fisher exact test were used to compare categorical variables. RESULTS: Significant higher posttreatment weighted maxillary alignment score was found in group 2. However, no significant difference was found between the groups concerning the mean total weighted PAR reduction (29.8 ± 9.9 vs 25.6 ± 8.7) and posttreatment total weighted PAR scores (1 vs 2). The PAR index score improvement (%) was similar between the groups (93.7 ± 7.1 vs 89.9 ± 13.0). No statistically significant difference was found between the groups for the total OGS score (32 vs 33). A lower score for marginal ridge height (4 vs 3) and a higher score for buccolingual inclination (7 vs 11), and a lower score for occlusal relationship (3 vs 1) were found in group 2. Canceled appointments (1.1 ± 0.7 vs 4.8 ± 1.6) and the number of missed appointments (0.6 ± 0.5 vs 1.1 ± 0.8) were statistically higher in group 2, whereas the total number of appointments (27.3 ± 8.8 vs 21.8 ± 5.4) were statistically less. The treatment duration was comparable in both groups. CONCLUSIONS: Reduced and irregular appointments during the pandemic resulted in significantly higher posttreatment weighted maxillary alignment and worsening of the buccolingual inclination. However, the PAR score improvement, total OGS score, and treatment duration were not affected.

Monitoring Salivary Levels of Interleukin 1 Beta (IL-1ß) and Vascular Endothelial Growth Factor (VEGF) for Two Years of Orthodontic Treatment: A Prospective Pilot Study.

RESULTS: A gradual increase in IL-1ß and VEGF was observed at alignment, reaching significance at space closure (p = 0.002 and p = 0.025, respectively). At finishing, both IL-1ß and VEGF declined, however, without reverting to baseline values (p = 0.172 and p = 0.207, respectively). Bland-Altman analysis showed the agreement between IL-1ß and VEGF in terms of a systematic increase, with a higher percentage difference for VEGF. CONCLUSIONS: The salivary levels of both IL-1ß and VEGF increased following orthodontic treatment and reached their peaks during the treatment stage of space closure. This novel approach provides a hint on how and when to sample saliva during orthodontic treatment to analyse bone remodelling.

Predictive factors for canine position in patients with unilateral cleft lip and palate.

OBJECTIVES: The aims were to compare cleft and non-cleft canine position, to find predictive factors for canine position and to assess surgically exposed canines. MATERIALS/METHODS: One hundred forty-eight individuals, born 1978-2005, with total unilateral cleft lip and palate (including Simonart's band <5 mm) treated in Gothenburg, were included. Canine angulation as well as vertical and horizontal position were assessed on panoramic radiographs (PAN) taken at the age of 10. Plausible predictive factors were registered from PAN, cast models and medical records. Data on spontaneous eruption or surgical exposure were available for 88 patients. Cleft- and non-cleft side was compared using paired t-test and Fisher's exact test. Multiple stepwise regression analysis and logistic regression analysis were used to detect possible predictors for cleft canine position. RESULTS: The cleft canine angulation was 29.3 ± 13.1 degrees (mean ± standard deviation) versus 7.6 ± 8.2 degrees on the non-cleft side (p < 0.001). Cleft canines were higher positioned and located closer to the midline compared to non-cleft canines (p < 0.001). Age for both hard palate closure and bone grafting, cleft lateral agenesis as well as transposition were associated with canine position. Cleft canines that required surgical exposure (28%) had an increased angulation and were higher positioned than spontaneously erupted canines (p < 0.001). LIMITATIONS: The shortcomings were the retrospective design and incomplete assessment of the buccal-palatal canine position on 2D images. CONCLUSIONS/IMPLICATIONS: With increased age for bone grafting, decreased age for hard palate closure and transposition, an association with abnormal canine position was found. A rigorous monitoring of cleft canine eruption is, therefore, advocated.

How sandblasting on lingual surfaces can be carried out with minimum enamel damage: An in vitro study on human teeth.

OBJECTIVE: The aim was to assess the extent of enamel damage sandblasting might cause and to identify a combination of sandblasting durations and MicroEtcher nozzle-tooth surface distance (NTD) resulting in the least enamel damage. MATERIALS AND METHODS: Lingual surfaces of 30 human teeth were sandblasted with 2 different distances: 1, 2mm and 3 different durations: 1, 2, 3s and photographed using a light microscope. The cavity depth and diameter of the sandblasted teeth were measured on the light microscope's pictures. A pilot study was performed to minimize possible combinations of sandblasting durations and distances. To validate the measurement method, sandblasted teeth were ground cut for comparison. Inter-examiner reliability was assessed with Bland-Altman analysis. Mann-Whitney U-test was used to detect cavity and diameter changes for every sandblasting duration and NTD combination. RESULTS: From the pilot study sandblasting durations 1,2 and 3s and NTD<2mm were chosen. The cavity diameter of the sandblasted area did not change with increased sandblasting duration nor NTD (P>0.05). The cavity depth of the sandblasted area increased statistically with an increased sandblasting duration (P<0.05) but did not increase with an increase NTD (P>0.05). The 95% limits of inter-examiner agreement were narrow. CONCLUSION: All distance and duration combinations tested caused enamel damage. Sandblasting duration had greater impact on the cavity depth than the NTD. The blasting duration should, therefore, not exceed 2s and the NTD should be held at maximum 2mm to minimize the risk of unintentional spread.

Web-based Fully Automated Cephalometric Analysis: Comparisons between App-aided, Computerized, and Manual Tracings.

OBJECTIVE: To compare the accuracy of cephalometric analyses made with fully automated tracings, computerized tracing, and app-aided tracings with equivalent hand-traced measurements, and to evaluate the tracing time for each cephalometric analysis method. METHODS: Pre-treatment lateral cephalometric radiographs of 40 patients were randomly selected. Eight angular and 4 linear parameters were measured by 1 operator using 3 methods: computerized tracing with software Dolphin Imaging 13.01(Dolphin Imaging and Management Solutions, Chatsworth, Calif, USA), app-aided tracing using the CephNinja 3.51 app (Cyncronus LLC, WA, USA), and web-based fully automated tracing with CephX (ORCA Dental AI, Las Vegas, NV). Correction of CephX landmarks was also made. Manual tracings were performed by 3 operators. Remeasurement of 15 radiographs was carried out to determine the intra-examiner and inter-examiner (manual tracings) correlation coefficient (ICC). Inter-group comparisons were made with one-way analysis of variance. The Tukey test was used for post hoc testing. RESULTS: Overall, greater variability was found with CephX compared with the other methods. Differences in GoGn-SN (°), I-NA (°), I-NB (°), I-NA (mm), and I-NB (mm) were statistically (p<0.05) and clinically significant using CephX, whereas CephNinja and Dolphin were comparable to manual tracings. Correction of CephX landmarks gave similar results to CephNinja and Dolphin. All the ICCs exceeded 0.85, except for I-NA (°), I-NB (°), and I-NB (mm), which were traced with CephX. The shortest analyzing time was obtained with CephX. CONCLUSION: Fully automatic analysis with CephX needs to be more reliable. However, CephX analysis with manual correction is promising for use in clinical practice because it is comparable to CephNinja and Dolphin, and the analyzing time is significantly shorter.

Delayed diagnosis of displaced and impacted canines - a prospective longitudinal study.

Objectives: To assess the frequency and reasons for delayed diagnoses of displaced/impacted canines and to determine to what extent this causes complications. In addition, to assess whether any preventive measures were taken.Materials and methods: Patients with displaced/impacted canines that were diagnosed late; i.e. at an age ≥12 years, were consecutively collected during September 2015 to September 2018 in the County Region of Halland, Sweden. Additionally, patients who had undergone surgical exposure or extraction of an impacted canine during the same time period were identified.Results: Eighty-four individuals (58% girls, 42% boys, mean age: 13.75 ± 1.53 years) with 114 impacted canines were detected among 33,488 adolescents aged 12-20 years, resulting in a low-frequency rate: 84 cases per 100,000 persons. Eighty-six percent of the delayed canines were in the maxilla, the rest in the mandible. Deciduous canines were present in 80% of the cases. Most patients had a dental examination at 9-11 years of age but the position of the canine was not documented in many cases. Root resorption of adjacent teeth was noticed in 13% of the patients. No new clinical procedures or guidelines were developed.Conclusions: The frequency of delayed diagnoses of displaced/impacted canines was low. To minimize the frequency even more, documentation of the canine position during the dental examination should not be forgotten at ages 9-11. Presence of the deciduous canine can be used as a clinical indicator that the position of the permanent canine needs to be investigated.

Space conditions, palatal vault height, and tooth size in patients with and without palatally displaced canines: A prospective cohort study.

OBJECTIVES:: To assess palatal vault height, tooth size, and dental arch dimensions in patients with unilateral and bilateral palatally displaced canines compared with a control group. MATERIALS AND METHODS:: A sample of 66 patients (mean age: 11.5 ± 1.0 years) with 22 unilateral palatally displaced canines (UPDCs), 22 bilateral palatally displaced canines (BPDCs), and 22 controls (C) were consecutively recruited. All three groups had dental casts that were scanned digitally using the OrthoX three-dimensional model scanner. Tooth size, palatal vault height, dental arch width, dental arch depth, dental arch length, and dental arch space were measured by the same examiner using the GOM software. Remeasurements were made in 10 randomly identified patients. RESULTS:: The palatal vault height was significantly lower in the BPDC group compared with controls. A significantly smaller mesial-distal crown width and, in general, more spacing in the maxilla were found in the UPDC and BPDC groups. No differences in arch length or arch width at the molar region were seen between the groups, while the arch length at the canine region was smaller in the UPDC and BPDC groups. However, this was observed in BPDC patients with both deciduous canines present and in most UPDC patients where the deciduous canine was present, compared with the control group, who had more permanent canines present. CONCLUSIONS:: Patients with PDC had greater reduction in tooth size compared with the control group. The arch length and arch width were similar in patients with and without PDC.

Glass-ionomer open exposure (GOPEX) versus closed exposure of palatally impacted canines: a retrospective study of treatment outcome and orthodontists' preferences.

Objectives: To investigate which surgical technique orthodontists prefer for exposing palatally impacted canines (PICs), and to compare closed exposure and glass-ionomer open exposure (GOPEX) with regard to pre- and post-surgical orthodontic variables. Materials and methods: A questionnaire with 19 questions and three cases visualising superficial, deep, or medial PICs was sent to 48 orthodontists working in a Swedish county. Sixty case records for patients with unilateral PICs from two centres were analysed; 30 patients having GOPEX (Centre A), and 30 undergoing closed exposure (Centre B). Pre- and post-surgical orthodontic variables were collected from the dental records. Results: The response rate was 81 per cent. There was an equal distribution of preference between open and closed exposure. Glass-ionomer cement (GIC) was predominately used as surgical packing in open exposure. No active traction was initiated until the canine erupted spontaneously. In the closed exposure cases, traction started shortly after exposure. The clinicians mentioned similar advantages of choosing one technique over the other and the main basis for the decision was the clinician's preference and not the location of the canine. There were no differences regarding post-exposure complications between the techniques. The overall treatment time was the same but there were fewer appointments and significantly shorter active treatment time with traction of the PIC in the GOPEX group. Limitations: Despite the homogeneity of the baseline patient characteristics, pre- and post-surgical orthodontic variables were analysed retrospectively, therefore, it is difficult to assess what impact these confounding factors may have had on the treatment time. Conclusions: The choice of exposure technique depends on the clinician's preferences. The active treatment time is shorter and the number of appointments fewer with open exposure when GIC is used as surgical packing.

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

Objective: 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. Design, settings, participants, and intervention: 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. Results: 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. Limitations: The results are only valid for patients with no space deficiency in the maxilla and with PDCs located in sector 2-4. Harms: No harms were detected. Conclusions: 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. Registration: This trial was registered at http://www.fou.nu/is/sverige, registration number: 211141.

A comparative study of cone beam computed tomography and conventional radiography in diagnosing the extent of root resorptions.

BACKGROUND: Root resorptions are assessed and diagnosed using different radiographical techniques. A comparison of the ability to assess resorptions on two-dimensional (2D) and three-dimensional (3D) radiographs is, hitherto, lacking. The aims of this study were to evaluate the accuracy of 2D (periapical radiographs, PA and panoramic radiograph, PAN) and 3D (cone beam computed tomography, CBCT) radiographic techniques in measuring slanted root resorptions compared to the true resorptions, a histological gold standard, in addition to a comparison of all the radiographic techniques to each other. METHODS: Radiographs (CBCT, PA, and PAN), in addition to histological sections, of extracted deciduous canines from thirty-four patients were analyzed. Linear measurements of the most and least resorbed side of the root, i.e., "slanted" resorptions, were measured using an analyzing software (Facad ®). For classification of slanted root resorptions, a modified Malmgren index was used. RESULTS: PAN underestimated the root length on both the least and most resorbed side. Small resorptions, i.e., low modified Malmgren scores, were more difficult to record and were only assessed accurately using CBCT. The root resorption scores were underestimated using PA and PAN. In assessment of linear measures, PAN differed significantly from both CBCT and PA. CONCLUSIONS: CBCT is the most accurate technique when measuring and scoring slanted root resorptions.

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.

AIM: 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. MATERIALS AND METHODS: 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. RESULTS: 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. LIMITATIONS: 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. CONCLUSIONS: 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. REGISTRATION: This trial was registered in 'FoU i Sverige' (http://www.fou.nu/is/sverige), registration number: 40921. PROTOCOL: The protocol was not published before trial commencement.

Extraction of the deciduous canine as an interceptive treatment in children with palatal displaced canines - part I: shall we extract the deciduous canine or not?

OBJECTIVES: To analyse whether extraction of the deciduous canines facilitates eruption of the palatal displaced canines (PDCs), and to analyse root resorption in adjacent teeth caused by the PDCs. MATERIALS AND METHODS: Eligibility criteria for participants were as follows: children at age 10-13 years with either maxillary unilateral or bilateral PDC, persisting deciduous canine and no previous experience of orthodontic treatment. Sixty-seven patients (40 girls and 27 boys; age: mean ± standard deviation: 11.4±1.0) with unilateral (45) or bilateral (22) PDCs were consecutively recruited and randomly allocated using permuted block randomization method to extraction or non-extraction. No patients dropped out after the randomization or during the study. Patients underwent a clinical examination and cone beam computed tomography at baseline (T0), after 6 (T1) and 12 months (T2). The total observation time was 24 months. Outcome measures were eruption, positional changes, length of time until eruption, and root resorption of adjacent teeth. The baseline images were measured blinded while the 6- and 12-month control images were not, since it was not possible to blind the extracted canine. RESULTS: Significantly more spontaneous eruptions of the PDCs were seen in the extraction group (EG) than in the control group (CG), with rates of 69 and 39 per cent, respectively, with a mean eruption time of 15.6±5.6 months in the EG and 18.8±5.8 months in the CG. Significant differences in changes between the groups, in favour of the EG, were found for all variables except for the sagittal angle. In the EG, the changes in the distances of the canine cusp-tip were larger during the first 6 months, while the change of apex was larger between 6 and 12 months. There were no significant differences in resorption of adjacent teeth between the groups. LIMITATIONS: Imputation values were used for the PDCs who had erupted at T2, since no x-rays were taken for ethical reasons, which might have given uncertainty in the positional changes between T1 and T2. CONCLUSIONS: Extraction of the deciduous canine is an effective treatment in patients with PDCs. Significantly more positional changes and shorter mean eruption time were seen in the EG. Resorptions of lateral incisors were seen in both groups, but none exceeded grade 2 (resorption up to half of the dentine thickness to the pulp). REGISTRATION: This trial was registered in "FoU i Sverige" (http://www.fou.nu/is/sverige), registration number: 40921. PROTOCOL: The protocol was not published before trial commencement.

Cone-beam computed tomography for assessment of palatal displaced canine position: a methodological study.

OBJECTIVE: To assess the inter- and intraexaminer reliability of a measurement method for evaluation of eruption angles and position of palatal displaced canines (PDCs) with cone-beam computed tomography (CBCT) images and to test the validity of the measured angles on a dry skull. MATERIALS AND METHODS: Twenty patients (eight boys, 12 girls; age 11.4±1.2 years) were randomly chosen among 67 patients from a study evaluating the interceptive effect of extracting the deciduous canine in children with PDCs. In total, 60 images were analyzed, because each patient had three CBCT examinations (baseline, 6-month control, and endpoint). Two observers assessed the following measurements twice: mesioangular and sagittal angle, vertical position, canine cusp tip, and canine apex to dental arch. The validity of the angular measurements was tested against angular measurements on a dry skull using mathematical formulations. RESULTS: The inter- and intraexaminer mean differences for angular and linear measurements were all low and statistically insignificant (P>.05). The mean differences between the physical and 3D measurements were 0.5±0.39 mm for the sagittal angle and 0.22±0.19 mm for the mesioangular angle. CONCLUSIONS: Linear and angular measurements on CBCT images are accurate and precise and can be used to assess the precise position of a PDC.

Interceptive Treatment Of Palatally Displaced Canines.

BACKGROUND: In 2% of the Swedish population the canine fails to erupt and in 85% of the cases the canine is palatally displaced. The most common interceptive treatment of palatally displaced canines (PDCs) is extraction of the deciduous canine at the age of 10-13 years and follow-up of the canine for 12 months to monitor whether its eruption path will normalize. In case the canine does not erupt spontaneously, a surgical exposure and orthodontic treatment is commonly considered. However, an early and easy interceptive treatment is preferable both from a health economic perspective as well as to reduce the risk of root resorption of the adjacent teeth and to avoid later comprehensive treatments. OBJECTIVE: The aims of this thesis were: to develop a reliable and valid method to measure the position of PDCs on 3D images (Cone Beam Computed Tomography, CBCT) (paper I). To evaluate children's subjective experience before, during and after extraction of the deciduous canine (paper II). To compare whether extraction of the deciduous canine more often results in spontaneous eruption of the permanent canine compared to non extraction (paper III) and to find out which clinical cases benefit from interceptive extraction (paper IV). MATERIALS AND METHODS: In total 89 PDCs in 67 children (10-13 years of age) were randomly assigned to either have their deciduous canine extracted (extraction group, EG) or not extracted (control group, CG). Clinical and radiographic examinations were carried out at baseline (TO), after 6 (T1) and 12 months (T2) in both groups. 3D images of 20 patients out of 67 were randomly chosen and measured by two dentists at different occasions. The validity of the method to measure the displaced canines was assessed by comparing measurements on the 3D images with measurements on a dry skull. Children who had extraction of the deciduous canine were asked to answer a questionnaire before, the same day as and one week after the extraction. RESULTS: The radiographic method to measure and assess the position of the PDCs on 3D images was reliable and had a high validity (paper I). The reported pain and discomfort were in overall low. The injection was experienced as more painful compared to the extraction, and analgesics were taken the first evening by 42% of the children (paper II). Extraction of the deciduous canine resulted in eruption of the PDCs in 69% of the cases compared to 39% in the CG. Significantly more positional changes and a shorter mean eruption time were seen in the EG (paper III). PDCs with a mesioangular angle of 103 degrees, distance of the canine cusp tip-dental arch plane of 2.5 mm and distance of the canine cusp tip-midline of 11 mm in patients < 11 years will likely erupt without interceptive extraction. However, PDCs with a less favourable position, i.e. a mesioangular angle of 116 degrees, canine cusp tip-dental arch plane of 5mm and canine cusp tip-midline of 6 mm, in patients > 11-12 years old, will not erupt spontaneously in spite of interceptive extraction of the deciduous canine (paper IV). CONCLUSIONS: The radiographic method to measure and assess the position of the PDCs was reliable and valid and can be used in future studies. Adequate analgesics and dose should be given to children before and after extracting the deciduous canine. Interceptive extraction of the deciduous canine at 10-13 years of age was effective and will result in significantly more spontaneous eruptions of the permanent canine compared to a control group. The cutoff points may be a helpful tool for the clinician to chose whether the patient benefit from interceptive extraction of the deciduous canine or whether immediate surgical exposure should be performed.

Pain, discomfort, and use of analgesics following the extraction of primary canines in children with palatally displaced canines.

BACKGROUND. Pain following the extraction of the primary canine in children with palatally displaced canines (PDC) as an interceptive treatment has not been investigated. AIMS. To describe pain, discomfort, dental anxiety, and use of analgesics following the extraction of primary canines in children with PDC. DESIGN. Forty-four children, aged 10-13 with PDC, were included. Pain intensity, discomfort, and analgesic consumption were rated the first evening and 1 week after the extraction of the primary canine. Dental anxiety was assessed pre-extraction, using the dental anxiety scale (DAS). A matched reference group also completed the DAS. RESULTS. No significant differences were found between the study and the reference group regarding the pre-extraction assessments. Post-extraction pain and discomfort was low. The experience of the injection was graded worse than the extraction, and more pain was rated at the evening post-extraction than during the extraction. Analgesics were used only the first evening. High correlation was detected between DAS and pain during injection and extraction. CONCLUSIONS. The experience of pain and discomfort during and after extraction of the primary canines is low, despite that 42% of the children used analgesics. Therefore, appropriate analgesics and recommendation doses pre- and post-extraction should be prescribed.

A systematic review of the interceptive treatment of palatally displaced maxillary canines.

The aim of this study was to assess whether interceptive treatment in the mixed dentition prevents impaction of palatally displaced canines (PDC) by systematically reviewing the literature. A literature search of PubMed, the Cochrane Library electronic databases, and Scopus was performed covering the period from January 1966 to May 2009. The inclusion criteria were mixed dentition with unilateral or bilateral PDC, randomized controlled trials (RCT), prospective and retrospective studies with untreated controls, and clinical trials comparing at least two treatment strategies. Three reviewers selected and extracted the data independently and evaluated the quality of the studies. Inter-examiner reliability was measured using the intraclass correlation coefficient (ICC). The search strategy resulted in 686 articles, of which two met the inclusion criteria. Because of the unequivocal results and heterogeneity in the study methods, the scientific evidence was too weak to fully evaluate the effect that interceptive treatment might have on PDC and which treatment modalities are most effective. The quality of the studies was rated as low because of inadequate sample selection and deficient description of sample size, confounding factors, uncertainty of randominization, and no blinding in measurements. The ICC value for total scores was >0.80, e.g. perfect agreement. To obtain reliable scientific evidence as to whether interceptive treatment prevents impaction of PDC and which treatment modalities are the most effective, better controlled and well-designed RCTs are needed. Future studies should also include assessment of patient satisfaction and pain experience as well as analysis of the costs and side-effects of treatments.