The Angle orthodontist最新文献

Objectives: To evaluate if mandibular growth was influenced by the mechanobehavior (magnitude and frequency) of temporomandibular joint (TMJ) loading, the hypotheses tested were: Time 1 (T1) mechanobehavior and age correlated with changes (Δ) in lengths of (1) ramus (CoAS-Go) and (2) mandible (CoP-Gn) at Time 2 (T2) after Herbst appliance therapy (HAT).

Materials and methods: Subjects had Class II skeletal malocclusions for which HAT was planned and gave informed consent to participate. Anatomy, including CoAS-Go and CoP-Gn, were derived from cone-beam computed tomography at both timepoints. T1 loading magnitudes were measured as TMJ energy densities (ED, mJ/mm3) using dynamic stereometry, loading frequencies were measured as jaw muscle duty factors (DFs, %) from at-home electromyography (EMG) recordings made by subjects, and mechanobehavior scores (MBS; MBS = ED2xDF, (mJmm3)2 %) were calculated for each TMJ. Generalized additive models tested for effects of T1 MBS and age on ΔCoAS-Go and ΔCoP-Gn.

Results: Fifteen subjects (eight females, seven males) with T1 age of 12.7 ± 1.3 years completed protocols and HAT of 12.0 ± 1.1 months. Subjects produced 37 daytime and 42 night-time electromyographic recordings of 6.3 ± 1.1 and 8.9 ± 1.3 hours, respectively. Normalized changes in ramal and mandibular lengths vs T1 overall MBS and age showed significant nonlinear relationships (P = .003 and < .0001 with adjusted R2= 0.54 and 0.74, respectively), where relatively larger MBS and younger age showed larger changes in ramal and mandibular lengths after HAT.

Conclusions: Initial mechanobehavior and age were significantly correlated with changes in lengths of the ramus and the mandible after Herbst appliance therapy.

Objectives: To study the effect of using reverse curve of Spee (RCOS) archwires or posterior vertical elastics with anterior bite turbos (ABTs) during deep overbite management.

Materials and methods: Eighty-one patients with excessive overbite treated with ABTs were divided into three equal groups: Group I (mean age = 15.82 years) received 0.016 × 0.022 nickel titanium RCOS archwires, Group II (mean age = 16.00 years) received posterior vertical elastics, and Group III (mean age = 17.35 years) received bite turbos alone. Standardized lateral cephalograms were taken at baseline (T1) and after overbite correction (T2).

Results: A total of 80 patients completed the study. All groups showed similar reductions in overbite. Group II required the shortest treatment duration (44.4 days), followed by Group I (55.7 days) and Group III (94.2 days, P < .001). Group I experienced lower incisor proclination (7.5°), true incisor intrusion (1 mm), and distal molar tipping. Group II exhibited posterior tooth extrusion (up to 1.1 mm and 0.42 mm in the lower and upper arches, respectively) with minimal incisor change. Group III overbite reduced mainly by passive eruption of lower posterior teeth. Vertical skeletal measurements increased significantly in all groups, with the smallest increase in Group III.

Conclusions: All three approaches corrected deep overbite successfully. Posterior elastics with bite turbos were the most efficient. RCOS wires with bite turbos produced greater proclination and intrusion of the lower incisors. Bite turbos alone achieved slower correction, primarily through eruption of lower posterior teeth.

Objectives: To evaluate the dentoskeletal effects of a miniscrew-anchored Herbst appliance using two different connection methods, elastic chains and metallic ligatures, compared with a conventional Herbst appliance, in adolescent patients with skeletal Class II malocclusion.

Materials and methods: A retrospective study was conducted involving 48 patients aged 10-15 years, divided into three groups: Group I (conventional) received conventional Herbst treatment; Group II (ligated) received miniscrew-anchored Herbst with metallic ligatures; and Group III (elastic) received miniscrew-anchored Herbst with elastic chains. Miniscrews were placed in the mandibular external oblique ridge. Lateral cephalograms were analyzed using Dolphin Imaging software to assess skeletal and dental changes before and after treatment.

Results: All groups showed significant improvements in overjet, molar relationship, and sagittal discrepancy. However, the elastic group exhibited the greatest control over mandibular incisor proclination, with a mean reduction of 3.51° in li/GoMe, compared with increases of 8.89° in the conventional and 2.04° in the ligated groups. SNB increased and ANB decreased in all groups, with the most pronounced skeletal changes observed in the conventional group. No miniscrew failures occurred.

Conclusions: Miniscrew-anchored Herbst appliances, particularly those using elastic chains, effectively reduce undesirable mandibular incisor proclination while maintaining therapeutic efficacy. The external oblique ridge proved to be a stable site for miniscrew placement.

Objectives: To characterize functional changes of the airway while wearing an appliance simulating severe arch constriction using level 3 polysomnography.

Materials and methods: For this pilot, single-blinded prospective randomized cross-over trial, 34 participants were recruited from the student/staff population of a dental school. Epworth Sleepiness Scale, STOPBANG questionnaire, lateral cephalograms, and digital dental casts were gathered from all patients. Arch constriction was simulated by adding 5 mm thickness to lingual aspects of the dentition using vacuum-formed retainers (VFRs). Each participant completed three at-home sleep studies with a level 3 sleep monitor: the initial baseline test, and after random allocation of 6 days wearing either the control appliance (regular-VFR), or the simulated arch constriction (SAC) appliance, and following crossover of appliances. Oxygen Desaturation Indices (ODIs) and Respiratory Event Index (REI) were compared.

Results: Use of the SAC appliance did not affect airway function: No significant difference (P > .05) was found in REI or ODI among the three groups. Five participants had REI values 5.0 or greater on at least one sleep study; however, this was unrelated to appliance use.

Conclusion: Simulated extreme dental arch constriction did not result in changes to REI. Constriction of the dental arches does not negatively affect airway function during sleep.

Objectives: To assess the effectiveness of virtual reality relaxation (VRR) as an intervention for reducing anxiety in adolescents and adults during the orthodontic bonding procedure.

Materials and methods: This prospective clinical study included 53 patients undergoing fixed orthodontic treatment at the Indiana University School of Dentistry. Participants were randomly assigned to one of two groups: the experimental group using VRR during orthodontic direct bonding or the control group receiving no distraction. Physiological measures (blood pressure [BP], heart rate [HR], and oxygen saturation) and psychological assessments (5-item State-Trait Anxiety Inventory-Short Form, and the Visual Analog Scale for Anxiety [VAS-A]) were collected at baseline (T0) and 30 minutes into the bonding procedure after bonding of one arch (T1). Repeated measures of analysis of variance were used to compare groups and timepoints.

Results: At T0, no statistically significant differences were found between the control and VRR groups across any psychological or physiological measures (P > .05). Although both groups showed significant reductions for physiological and psychological measures from T0 to T1 (P < .01), the VRR group reported significantly lower VAS-A scores, HR, and diastolic BP at T1 than the control group (P < .05).

Conclusions: VRR effectively reduced psychological and physiological anxiety during orthodontic bonding procedures, supporting VRR as a promising adjunctive tool in managing dental anxiety during orthodontic care.

Objectives: To assess the predictability of Invisalign First in achieving planned dental arch expansion in mixed dentition.

Materials and methods: Following PRISMA guidelines and a PROSPERO-registered protocol (CRD420251083929), electronic databases were searched up to July 2025. Eligible studies included data evaluating Invisalign First for dental arch expansion in mixed dentition. Predictability, defined as ratio of achieved to planned expansion, was the primary outcome. Meta-analyses of proportions were performed separately for maxillary and mandibular arches using binomial modeling on logit scale. Correlation analyses and univariate linear regression were conducted to assess the relationship between planned expansion and achieved predictability, globally and by arch and tooth group. Risk of bias was evaluated with ROBINS-I and publication bias by funnel plot and Egger's and Begg's tests. Certainty of evidence was assessed with GRADE.

Results: Nine studies were included in the systematic review and eight in the meta-analysis. Pooled predictability of expansion in the maxilla was 65%, with the lowest at permanent first molars (58%) and the highest at deciduous canines (70%). Expansion in the mandible showed higher predictability (71%), peaking at deciduous canines (75%). Correlation and regression analyses found no significant association between amount of planned expansion and achieved predictability in any subgroup. No evidence of publication bias was found, and findings remained robust on sensitivity analysis. GRADE certainty was low (maxilla) and moderate (mandible).

Conclusions: Invisalign First demonstrates modest to moderate predictability for dental arch expansion in mixed dentition, particularly in the mandibular arch and anterior teeth, though limitations persist in the posterior maxilla.

Objectives: To evaluate dimensional stability of models fabricated using stereolithography (SLA) 3D printing.

Materials and methods: Twelve resin models were printed from a STL file using an SLA 3D printer, according to manufacturer specifications. Dimensional stability was assessed through 4752 total measurements across upper and lower arches at eight timepoints: immediately after printing (T0), 3 hours (T1), 6 hours (T2), 12 hours (T3), 24 hours (T4), 7 days (T5), 30 days (T6), and 6 months (T7). Measurements were made in triplicate with a 6-inch digital caliper: intermolar distance (central grooves and mesiobuccal cusp tips), intercanine distance (cusp tips), and mesiodistal tooth size (maximum crown width of 28 teeth). Linear mixed models (restricted maximum likelihood) were used to assess the effects of time, arch, side, measurement/tooth type, and their interactions, with dental models as a random effect. Bonferroni post hoc tests identified pairwise differences, and model assumptions were verified.

Results: Significant effects of time were detected for transverse distances (P = .002) and mesiodistal tooth sizes (P < .001). These effects did not show significant interactions with arch, side, or type of measurement/tooth (P > .05). Both transverse widths and tooth sizes showed a statistically significant reduction starting from evaluation T5 (after 7 days of printing).

Conclusions: Orthodontic models produced by SLA 3D printing maintain high dimensional accuracy in the short term, supporting their immediate use in clinical settings for aligner fabrication. However, delayed use or prolonged storage can lead to measurable distortions that may compromise appliance fit and treatment efficacy.

Objectives: To evaluate the impact of presurgical infant orthopedics (PSIO) on nasolabial appearance among three PSIO methods (modified Grayson's technique, DynaCleft nasal elevator, OrthoAligner NAM with DynaCleft nasal elevator) and no-PSIO in children with unilateral cleft lip and palate (UCLP) at 4 years' follow-up.

Materials and methods: This study took place in an academic and a peripheral center at which patients with UCLP were treated and followed. A total of 48 patients with UCLP were divided into four groups of 12 patients each. Group 1 underwent PSIO using modified Grayson's technique. Group 2 received PSIO incorporating DynaCleft nasal elevator. Group 3 treatment involved OrthoAligner NAM in combination with DynaCleft nasal elevator, whereas Group 4 did not receive any form of PSIO. Asher-McDade Aesthetic Index (AMAI) and Cleft Aesthetic Rating Scale (CARS) were used to assess nasolabial appearance 4 years post-lip surgery (mean age: 4.3 years ± 6 months) on standardized photographs of the nasolabial region. Kruskal-Wallis test was used to assess nasolabial appearance scores among treatment groups.

Results: Nasolabial appearance showed no significant differences between PSIO and no-PSIO groups across facial esthetic indices regarding nasal form (P = .819), deviation of the nose (P = .403), shape of the vermillion border (P = .801), nasal profile including upper lip (P = .726), nose (P = .973), and lips (P = .72).

Conclusions: In patients with UCLP, there was no significant difference in nasolabial appearance 4 years after lip repair when comparing three different PSIO modalities to no-PSIO group.

Objectives: Mechanical compression of the periodontal ligament (PDL) is a key trigger of orthodontically induced root resorption (OIRR). Although PDL compression during the early phase of orthodontic force application correlates strongly with OIRR severity, associated cellular events remain insufficiently defined. This study aimed at elucidating mechanisms underlying the initiation of OIRR, focusing on PDL compression and associated cellular responses, and identifying cellular targets through which lithium exerts inhibitory effects.

Materials and methods: Thirty-seven 10-week-old male Wistar rats were assigned to lithium-treated and saline groups. Daily intraperitoneal injections were administered, and a 25 cN mesial orthodontic force was applied to the maxillary first molar for 14 days. PDL thickness was evaluated using microcomputed tomography. Histological analyses quantified the OIRR area, apoptotic cell count, and odontoclast number.

Results: In both groups, early PDL compression ratios showed strong positive correlations with OIRR area and early apoptotic cell counts. Lithium significantly reduced OIRR but did not alter PDL compression compared with saline. At comparable PDL compression ratios, the lithium group exhibited consistently smaller OIRR areas and fewer early apoptotic cells. The early odontoclast numbers remained low and showed no intergroup differences. These findings suggest that the protective effect of lithium was primarily mediated by the suppression of early apoptosis, cellular response to PDL compression.

Conclusions: Early PDL compression and apoptosis play pivotal roles in OIRR initiation and are potential predictive markers. Lithium attenuated OIRR by suppressing early apoptosis without altering PDL compression, highlighting early apoptosis as a promising therapeutic target for OIRR prevention.

Objectives: To evaluate the effect of miniscrew-assisted rapid palatal expansion (MARPE) on root resorption, buccal bone thickness, and tooth inclination.

Materials and methods: This study included 30 patients with maxillary constriction who were treated with MARPE. The device was left in place for 6 months for retention. Cone-beam computed tomography (CBCT) images were taken before treatment and after 6 months. CBCT images were analyzed for root length, buccal bone thickness, and tooth inclination for premolars and first molar on both sides. A paired t-test was used to compare between pretreatment and posttreatment root lengths, buccal bone thickness, and buccal tooth inclination.

Results: No significant differences were found between pretreatment and posttreatment root lengths of all measured teeth (P value > .05). A significant difference was found in the buccal bone thickness at the right second premolar at the levels of 2 mm and 8 mm (P = .049 and P = .039, respectively) and at the level of 2 mm for the left second premolar (P = .009). Buccal bone thickness at the right and left mesiobuccal root of the first molar at 8 mm was significantly reduced after expansion (P = .001). The difference between pre-expansion and postexpansion in tooth inclination ranged between -1.87 and 0.27. Only the inclination of the left first molar was significantly increased after expansion.

Conclusions: No root resorption was caused by the bone-borne MARPE. No change in buccal bone thickness and inclination of most of the posterior maxillary teeth was found.