To Örebro University

Överkäkshörntänderna är den tand i bettet som har längst väg att eruptera och som uppvisar den högsta retentionsprevalensen. Tidig diagnostik av ektopiska hörntänder och efterföljande interceptiv vård är av största vikt för att motverka att ektopiska hörntänder blir retinerade. En korrekt utförd interceptiv behandling kan bidra till att både undvika skador på granntändernas rötter och en omfattande ortodontisk behandling som en framdragning av en hörntand innebär. Interceptiv vård löser inte problemet med alla ektopiska hörntänder. I de fall då hörntanden befinner sig bakom överkäkscentraler, är det viktigt att en effektiv och evidensbaserad friläggning- och ortodontisk framdragningsteknik sätts in.

The maxillary canines are the teeth in the dental arch with the longest eruption path and demonstrate the highest prevalence of impaction. Early diagnosis of the palatally displaced canines (PDC) and subsequent interceptive treatment are of paramount importance to prevent the PDC from becoming impacted. Properly executed interceptive treatment can contribute to avoiding root resorptions of the adjacent teeth, as well as extensive and burdensome treatment of PDC involving surgical exposure and subsequent orthodontic treatment. The interceptive treatment, however, does not always success to correct the eruption path of the PDC. In cases with unsuccessful outcomes of the interceptive treatment, it is crucial to opt for an effective and evidence-based exposure and orthodontic traction technique.

BACKGROUND: Quad Helix (QH) is the appliance most preferred by orthodontists to correct unilateral posterior crossbite in the early mixed dentition while other orthodontists suggest rapid maxillary expansion (RME) on deciduous teeth in these patients.

OBJECTIVES: To evaluate and compare perceived pain intensity, discomfort, functional jaw impairment, and analgesic consumption during the first week of treatment with either RME or QH appliances.

TRIAL DESIGN: Two-arm parallel group, two-centre, randomized controlled trial.

MATERIAL AND METHODS: Seventy-two patients, mean age 9.5 (SD ±0.8) years, with unilateral posterior crossbite requiring maxillary expansion were randomly allocated to either the RME (22 boys, 14 girls) or QH (22 boys, 14 girls) group. Validated questionnaires were used to assess pain intensity, discomfort, jaw function impairment, and analgesic consumption, on the first, fourth, and seventh days after appliance insertion and activation.

BLINDING: Due to clinical limitations, only the outcome assessors were blinded to the groups to which the patients were allocated.

RESULTS: Seventy patients completed the questionnaires. Pain from the tongue and chafe from the appliance were significantly higher in the QH group on the first day of treatment (P = 0.003 and P = 0.000, respectively). On the fourth day, the chafe from the appliance was still significantly higher in the QH group (P = 0.007). Speech was affected in both groups on day 1; this impairment continued and was significantly higher in the RME group days 4 and 7. No significant difference in analgesic consumption was found between the groups at any time. The analgesic consumption was highest at day 1 of treatment.

HARMS: No harm was observed in any patient.

LIMITATIONS: Double blinding was not possible due to the clinical limitations.

CONCLUSION: During the initial 4 days of treatment, pain from the tongue and chafe from the appliance caused the most reported inconvenience in the patients in the QH group. A majority of reported visual analogue scale values were in the lower mid-range, suggesting low to moderate pain and discomfort in both groups.

CLINICAL TRIAL REGISTRATION: NCT04458506.

Objectives: To compare the long-term skeletal effects of tooth-borne (TB) and tooth-bone-borne (TBB) rapid maxillary expansion in growing children, using 3D imaging.

Materials and methods: In total, 52 consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years (SD 1.3), or the TBB group, mean age 9.5 years (SD 1.2). Cone-beam computed tomography records and plaster models were taken before (T-0), directly after (T-1), 1 year after (T-2), and 5 years after expansion (T-3).

Randomization: Participants were randomly allocated in blocks of different sizes, using the concealed allocation principle in a 1:1 ratio. The randomization list was also stratified by sex to ensure homogeneity between groups.

Blinding: Due to clinical limitations, only the outcome assessors were blinded to the groups to which the patients were allocated.

Results: At T-1, the midpalatal suture at its anterior part showed a statistically significant difference between the groups with a mean of 0.6 mm (CI 0.2-1.1) more expansion in the TBB group (P < 0.01). This difference was also more evident in boys at T-1 with a mean of 0.8 mm (CI 0.2-1.4) (P < 0.01). These differences, however, blotted out at T-2 and T-3. The nasal width also showed similar differences between the groups, with a significantly larger expansion in the TBB group by a mean of 0.7 mm (CI 0.1-1.4) (P = 0.03). This group difference in favour of the TBB group was maintained at T-2 (1.6 mm) and T-3 (2.1 mm) (P < 0.01 T-2 and T-3, respectively).

Conclusions: Skeletal expansion in the midpalatal suture was significantly higher in the TBB group; however, the magnitude of this expansion was around 0.6 mm more and may not be clinically significant. Skeletal expansion at the level of the nasal cavity was significantly higher in the TBB group. There were no differences between boys and girls with regard to skeletal expansion.

Objective: Development of a new questionnaire, Oral Health-Related Quality of Life - Neurosensory Disturbances after Orthognathic Surgery (OHRQL-NDO), designed to measure the effects of neurosensory disturbance (NSD) on patients' oral health-related quality of life (OHRQL) and to evaluate reliability and validity of this questionnaire.

Materials and methods: A questionnaire including 11 items was constructed. Thirty patients with NSD affecting the lower lip and/or chin following orthognathic surgery were included. Convergent validity was assessed by comparing OHRQL-NDO with OHIP-14 and two global questions. Test-retest reliability was assessed by asking the patients to complete OHRQL-NDO at two different occasions with an interval of two to three weeks.

Results: The internal consistency, measured with Cronbach's alpha, was 0.84. The test-retest reliability, measured with ICC, was 0.89 (95% CI 0.77-0.95). The correlation between the mean sum score for the OHRQL-NDO and the mean sum score for the OHIP-14 was r = 0.75, using Pearson correlation coefficient. The correlations between the mean total score for the OHRQL-NDO and the global questions 1 and 2 were r = 0.74 and r = 0.72, respectively.

Conclusions: The current instrument OHRQL-NDO is a promising test, but needs further development to better capture the different aspects of OHRQL. Further tests of the questionnaire must follow in other samples to finalize the instrument.

Purpose: The aim of this study was to evaluate the reliability of the Vectra M3 (3D Imaging System; Canfield Scientific, Parsippany, NJ, USA) in detecting chin asymmetry, and to assess whether the automatic markerless tracking function is reliable compared to manually plotting landmarks.

Materials and Methods: Twenty subjects (18 females and 2 males) with a mean age of 42.5 +/- 10.5 years were included. Three-dimensional image acquisition was carried out on all subjects with simulated chin deviation in 4 stages (1-4 mm). The images were analyzed by 2 independent observers through manually plotting landmarks and by Vectra software auto-tracking mode. Repeated-measures analysis of variance and the Tukey post-hoc test were performed to evaluate the differences in mean measurements between the 2 operators and the software for measuring chin deviation in 4 stages. The intraclass correlation coefficient (ICC) was calculated to estimate the intra-and inter-examiner reliability.

Results: No significant difference was found between the accuracy of manually plotting landmarks between observers 1 and 2 and the auto-tracking mode (P =0.783 and P =0.999, respectively). The mean difference in detecting the degree of deviation according to the stage was <0.5 mm for all landmarks.

Conclusion: The auto-tracking mode could be considered as reliable as manually plotted landmarks in detecting small chin deviations with the Vectra (R) M3. The effect on the soft tissue when constructing a known dental movement yielded a small overestimation of the soft tissue movement compared to the dental movement (mean value<0.5 mm), which can be considered clinically non-significant.

Objectives: To assess and compare the three-dimensional treatment changes in palatal surface area and volume using either tooth-borne (TB) or tooth bone-borne (TBB) rapid maxillary expanders and to evaluate the long-term effects of the two devices and the incidence of the relapse between the groups.

Materials and Methods: A total of 52 consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years (standard deviation [SD], 1.3), or the TBB group, mean age 9.5 years (SD, 1.2). Study casts were taken before, directly after, 1 year after, and 5 years after expansion. Study casts were digitized, superimposed, and evaluated. Participants were randomly allocated in blocks of different sizes using the concealed allocation principle in a 1:1 ratio.

Results: Changes in palatal volume, palatal surface area, and palatal projection area within and between the groups up to 5 years after expansion followed the same pattern and did not show any statistically significant differences between the groups. Relapse was seen in 15% of the patients. It seemed that open-bite and a Class III growth pattern could be assumed as prognosis-deteriorating factors in regard to stability of the treatment.

Conclusions: There were no significant differences between the TB and TBB groups in palatal volume, palatal shell area, or palatal projection area directly after expansion or at 1 year and 5 years after expansion, which implies that the two devices gave rise to the same immediate and long-term outcomes. (Angle Orthod. 2022;92:589-597.)

Objectives: To explore whether there were any differences in orthodontic treatment need, treatment complexity, treatment time, or the number of visits between a group of children receiving early intervention (extraction of upper and lower deciduous canines) and an age- and condition-matched control group without intervention.

Materials and Methods: Patient records and study casts in the late mixed or early permanent dentitions of 46 subjects (20 from the extraction group and 26 from the control group) of an earlier prospective longitudinal study were retrieved. Orthodontic treatment need and complexity were assessed by the index of complexity, outcome, and need (ICON). Statistical calculations were performed by t-test for parametric outcome variables (treatment time, number of visits, and orthodontic treatment need) and Fisher exact test for the categorical variable (tooth extractions).

Results: There were no statistically significant differences between the groups in ICON scores of orthodontic treatment need (extraction group, mean score 59.8; control group, mean score 52.8), number of visits (mean of about 15 visits for both groups), or treatment time (extraction group, mean 21.5 months; control group, mean 20.3 months). The extraction of permanent teeth was more prevalent in the deciduous canine extraction group (59%) as compared with the control group (28%); however, this was not statistically significant (P = .07) but showed a tendency toward worsening the crowding and the future need of orthodontic extractions.

Conclusions: Early removal of deciduous primary canines will reduce neither the need for later orthodontic treatment nor its complexity, nor will it shorten the treatment time.

OBJECTIVE: To evaluate the costs of open and closed surgical exposure and subsequent orthodontic treatment for the correction of palatally displaced canines (PDCs).

TRIAL DESIGN: A multicentre, two-arm parallel group randomized controlled trial.

METHODS: One hundred twenty adolescents between 9 and 16 years of age, from three orthodontic specialist centres, were randomized to one of the two surgical exposure interventions. The randomization was conducted according to a two-arm parallel group 1:1 allocation ratio, using computerized lists with block randomization. In both the surgical techniques, whole mucoperiosteal flaps were raised, and bone covering the PDCs was removed. In the open technique, glass ionomer was built up on the PDC crown - reaching above the mucosa through a hole punched in the flap - to allow the canine to erupt autonomously. After eruption, the canine was orthodontically moved above the mucosa. In the closed technique, an eyelet was bonded onto the PDC, the flap was repositioned and the canine was orthodontically moved beyond the mucosa. The trial ended when the PDC was successfully aligned in the dental arch.Cost analysis was performed including costs for surgery, orthodontic treatment, emergency visits, and material, as well as costs for transports and time spent in connection with every appointment.

BLINDING: Patients and caregivers could not be blinded due to obvious limitations of the clinical setting, while outcome assessors and data analysts were blinded.

RESULTS: A cost-minimization analysis was performed since both exposure groups succeeded equally well in terms of treatment effects. The two different surgical exposures and following orthodontic treatments did not differ significantly in terms of costs.

GENERALIZABILITY AND LIMITATIONS: Costs are estimated in the Swedish setting, which needs to be considered if applying the results in other settings. Calculations of total cost do not include finishing, debonding, retention, and follow-up.

CONCLUSION: There is no significant difference in costs between closed and open surgical exposure with following orthodontic treatments in PDCs.

TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02186548.

OBJECTIVES: To compare treatment time, patients' perceptions during orthodontic treatment, dental fear and side effects, between open and closed surgical exposures in patients with palatally displaced canines (PDCs).

TRIAL DESIGN: Multicentre, randomized controlled trial, with random 1:1 allocation of two parallel groups.

MATERIALS AND METHODS: One hundred and twenty patients from three different orthodontic centres were randomized into one of the two intervention arms, open or closed surgical exposure. Both techniques had mucoperiosteal flaps raised and bone removed above the PDCs. In open exposure, tissue was removed above the canine, and glass ionomer - reaching above soft tissue - was built on the crown. The canine was then left to erupt spontaneously, prior to orthodontic alignment. At closed exposure, a chain was bonded to the canine and orthodontic traction was applied under the mucosa until eruption. Orthodontic alignment of the canines was undertaken after eruption into the oral cavity, with fixed appliances in both groups. All participants were treated according to intention to treat (ITT).

BLINDING: Due to the nature of this trial, only outcome assessors could be blinded to the intervention group.

RESULTS: One hundred and seventeen patients completed the trial. All PDCs were successfully aligned. Total treatment time was equal in the two techniques, mean difference -0.1 months (95% CI -3.2 to 2.9, P = 0.93). The closed group experienced more pain and discomfort during the active orthodontic traction. Dental fear, root resorption and periodontal status did not show any clinically significant differences between the groups.

GENERALIZABILITY: Results of this randomized controlled trial (RCT) can be generalized only to a similar population aged 9-16 years, if exclusion criteria are met.

CONCLUSION: The closed exposure group experienced more pain and discomfort mostly during active orthodontic traction. All other studied outcomes were similar between the two exposure groups.

CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02186548 and Researchweb.org, ID: 127201.

OBJECTIVES: To evaluate and compare the skeletal and dentoalveolar effects of tooth-borne (TB) and tooth-bone-borne (TBB) rapid maxillary expansion (RME).

MATERIALS AND METHODS: Fifty-two consecutive patients who met the eligibility criteria were recruited and allocated to either the TB group, mean age 9.3 years [standard deviation (SD) 1.3], or the TBB group, mean age 9.5 years (SD 1.2). Cone-beam computed tomography (CBCT) records and plaster models were taken before (T0), directly after (T1), and 1 year after expansion (T2). Dentoalveolar and skeletal measurements were made on the CBCT images. The dental expansion was also measured on the plaster models.

RANDOMIZATION: Participants were randomly allocated in blocks of different sizes using the concealed allocation principle in a 1:1 ratio. The randomization list was also stratified by sex to ensure homogeneity between groups.

BLINDING: Due to clinical limitations, only the outcomes assessors were blinded to the groups to which the patients were allocated.

RESULTS: Skeletal expansion in the midpalatal suture and at the level of the nasal cavity was significantly higher in the TBB group. However, the magnitude of the expansion in the midpalatal suture was around 1 mm [95 per cent confidence interval (CI) 0.5-1.7, P = 0.001] more and perhaps not clinically significant. The magnitude of the expansion at the level of the nasal cavity was almost two times higher in the TBB group (95 per cent CI 0.7-2.6, P = 0.001). The dental expansion, alveolar bending, tipping of the molars, and stability 1 year post-expansion did not show any statistically significant differences between the groups. The actual direct cost of the treatment for the TBB group was approximately €300 higher than TB group.

LIMITATIONS: Double blinding was not possible due to the clinical limitations.

CONCLUSIONS: In young preadolescents with constricted maxilla and no signs of upper airway obstruction, it seems that conventional TB RME achieves the same clinical results with good stability 1 year post-expansion at lower cost.

TRIAL REGISTRATION: The trial was not registered.