Perception of Esthetic Orthodontic Appliances: An Eye Tracking and Cross-sectional study

ObjectiveTo evaluate the perception of esthetic orthodontic appliances by means of eye-tracking measurements and survey investigation.Materials and MethodsEn face and close-up images with different orthodontic appliances (aligner appliance [a], aligner appliance and attachments [b], lingual appliance [c], ceramic brackets [d], no appliance [e; control]) were shown to 140 participants. Eye movement and gaze direction was recorded by eye-tracking system. For different anatomical areas and areas of the appliances, time to first fixation and total fixation time were recorded. The questions included in a visual analog scale regarding individual sentiency were answered by the participants.ResultsFor all groups, the anatomical landmarks were inspected in the following order: (1) eyes, (2) mouth, (3) nose, (4) hair, and (5) ears. Only in group d, first fixation was on the mouth region (1.10 ± 1.05 seconds). All appliances except the lingual appliance (1.87 ± 1.31 seconds) resulted in a longer fixation on the mouth area (a, 2.97 ± 1.32 seconds; b, 3.35 ± 1.38 seconds; d, 3.29 ± 1.36 seconds). For close-up pictures, the fastest (0.58 seconds) and longest (3.14 seconds) fixation was found for group d, followed by group b (1.02 seconds/2.3 seconds), group a (2.57 seconds/0.83 seconds), and group c (3.28 seconds/0.05 seconds). Visual analog scale scoring of questions on visibility were consistent with eye-tracking measurements. With increasing visibility, the feeling of esthetic impairment was considered higher.ConclusionsLingual orthodontic appliances do not change how the face is perceived. Other esthetic orthodontic appliances may change the pattern of facial inspection and are different in subjective perception.     

舌侧矫治器对牙周致病菌的影响

目的研究舌侧矫治器对患者牙周临床指标和牙周致病菌的影响。方法收集成年正畸治疗患者55例资料,28例使用颊侧矫治器作为对照组,27例使用舌侧矫治器作为试验组,于治疗前和治疗6个月后,分别记录菌斑指数、龈沟出血指数、探诊深度,PCR检测龈下菌斑中牙龈卟啉单胞菌(Porphyromonas gingivalis,Pg)、伴放线放线杆菌(Actinobacillus actinomycetemcomtans,Aa)、福赛斯坦氏菌(Tannerella forsythensis,Tf)3种牙周致病菌的检出率。结果治疗6个月试验组菌斑指数、龈沟出血指数、探诊深度分别为2.36±0.71、2.05±0.49、(3.43±0.56)mm,对照组分别为1.86±0.44、1.67±0.25、(2.87±0.74)mm,2组间差异均有统计学意义(P<0.05);试验组Pg、Aa检出率分别为37.0%和22.2%,对照组的Pg、Aa检出率分别为14.3%和10.7%,试验组高于对照组(P<0.05)。结论舌侧矫治器,较颊侧矫治器,对牙周临床指标影响更大,可造成更多的牙周致病菌聚集。     

材料厚度对无托槽隐形矫治器固位力影响的实验研究

目的研究材料厚度对无托槽隐形矫治器在不同牙位脱位时固位力大小的影响,为临床设计附件及指导患者摘戴矫治器提供理论参考。方法制作标准下颌牙列阳模四副及相应的无托槽隐形矫治器四副。研究分为4组：1．00mm厚度无附件组,0．75mm厚度无附件组,1．00mm厚度有附件组,0．75mm厚度有附件组。采用万能材料试验机测试在不同牙位脱位时矫治器固位力的大小。结果不同材料厚度及附件设计影响下四组间矫治器固位力有统计学差异（F=10．10,P〈0．01）。附件能明显增加隐形矫治器固位力,1．00mm有附件组、0．75mm有附件组与其他无附件组比较,平均脱位力值大（P〈0．05）;1．00mm厚度有附件组比0．75mm厚度有附件组平均脱位力值大（P〈0．05）;脱位部位不同对固位力影响有统计学差异（F=12．03,P〈0．01）,在第二磨牙颊侧及第一磨牙舌侧测试时平均脱位力值较小。结论附件能够显著增加隐形矫治器固位力;1．00mm厚度有附件隐形矫治器固位力较大。     

Differences in psychological traits between lingual and labial orthodontic patients: Perfectionism,body image,and the impact of dental esthetics

Objective:To examine some of the patients'' psychological traits in relation to their levels of perfectionism and their body image, and to discover whether these differ between lingual and labial orthodontic patients.Materials and Methods:A cross-sectional study was designed with a consecutive sample of 80 patients attending a private orthodontic office. Three questionnaires were used to assess the patients'' body image and level of perfectionism. The mean age was 33 years. The men numbered 32 and the women 48. The validated Spanish version of the Psychosocial Impact of Dental Aesthetic Questionnaire (PIDAQ) was used to assess the psychosocial impact of their dental esthetics. The Multidimensional Perfectionism Scale (MPS) was used to assess how perfectionist the patients were. A version of the Multidimensional Body-Self Relations Questionnaire (MBSRQ) was used for assessment of their body image. Student''s t-test was used to compare the means and 95% confidence intervals (P < .05), and a logistic regression model was used for multivariate analysis.Results:The PIDAQ (55.4 vs 60, P  =  .218) and MBSRQ (128.7 vs 125.9, P  =  .523) results of the patients who chose lingual orthodontics did not differ significantly from those who opted for labial orthodontics. However, the MPS scores of the lingual orthodontic patients were significantly higher (95.9 vs 86.3, P  =  .044), and high social class, over 30 years of age, and perfectionist traits were significant independent variables in this group.Conclusions:This pilot study may indicate that lingual orthodontic patients are more perfectionists than labial orthodontic patients.     

Activation and installation of orthodontic appliances temporarily impairs mastication:: A systematic review with meta-analysis

ObjectivesTo investigate the masticatory (masticatory performance, bite force, swallowing threshold, muscle activity, and questionnaires) and nutritional (nutrient intake) impacts of the activation and/or installation of different orthodontic appliances (fixed labial, lingual appliances, and clear aligners).Materials and MethodsSix electronic databases and gray literature were searched (up to May 2021) for relevant studies evaluating mastication and nutrition after activation/installation of orthodontic appliances. This review followed PRISMA guidelines and was registered at PROSPERO (CRD42020199510). The risk of bias (RoB 2 and ROBINS-I) and evidence quality Grading of Recommendations Assessment, Development, and Evaluation were analyzed.ResultsOf 4226 recorded and screened, 15 studies were finally included. Masticatory performance (standardized mean difference [SMD]: 1.069; 95% coefficient interval [CI]: 0.619 to 1.518) and bite force (SMD: -2.542; 95% CI: −4.867 to −0.217) reduced in the first 24 to 48 hours of fixed labial appliance installation/activation, but they were both normalized after 30 days (P > .05). The swallowing threshold remained constant (P > .05). Nutritional intake was rarely reported but showed copper (P = .002) and manganese (P = .016) reductions, with higher calorie and fat intake (P < .05). Lingual appliances impacted chewing more than labial, and clear aligner wearers reported fewer chewing problems (P < .001). Low to very low levels of evidence were found.ConclusionsBased on low to very low levels of evidence, mastication was reduced during the first 24 to 48 hours of fixed labial appliance activation/installation, but it was transitory (up to 30 days). Due to insufficient data, the nutritional impact of orthodontic appliances was not conclusive.     

A randomized clinical trial comparing mandibular incisor proclination produced by fixed labial appliances and clear aligners

Objective:To compare the mandibular incisor proclination produced by fixed labial appliances and third generation clear aligners.Materials and Methods:Patients underwent a course of orthodontic treatment using either fixed labial appliances or clear aligners (Invisalign). Mandibular incisor proclination was measured by comparing pretreatment and near-end treatment lateral cephalograms. Eligibility criteria included adult patients with mild mandibular incisor crowding (<4 mm) and Class I skeletal bases (ANB, 1–4°). The main outcome was the cephalometric change in mandibular incisor inclination to the mandibular plane at the end of treatment. Eligible patients picking a sealed opaque envelope, which indicated their group allocation, was used to achieve randomization. Data was analyzed using a Welch two-sample t-test.Results:Forty-four patients (mean age, 26.4 ± 7.7 years) were randomized in a 1:1 ratio to either the fixed labial appliance or the clear aligner group. Baseline characteristics were similar for both groups: Fixed appliance mean crowding was 2.1 ± 1.3 mm vs clear aligner mean crowding, 2.5 ± 1.3 mm; pretreatment mean mandibular incisor inclination for the fixed appliance group was 90.8 ± 5.4° vs 91.6 ± 6.4° for the clear aligner group. Fixed appliances produced 5.3 ± 4.3° of mandibular incisor proclination. Clear aligners proclined the mandibular incisors by 3.4 ± 3.2°. The difference between the two groups was not statistically significant (P > .05).Conclusion:There was no difference in the amount of mandibular incisor proclination produced by clear aligners and fixed labial appliances in mild crowding cases.     

Effect of clear aligner therapy on the buccolingual inclination of mandibular canines and the intercanine distance

Objective:To compare the changes in buccolinugal inclination of mandibular canines and intercanine distance in patients treated with clear aligners to those treated with preadjusted edgewise appliances.Materials and Methods:The buccolingual inclination of mandibular canines and the intercanine distance were measured on pre- and posttreatment cone-beam computed tomograms of 30 patients who had been treated with clear aligners and 30 patients who had been treated with fixed preadjusted edgewise appliances. Differences between the aligner and fixed appliance groups and between pre- and posttreatment measurements were tested for statistical significance.Results:In both groups, most of the mandibular canines had positive buccolingual inclinations (ie, their crowns were positioned lateral to their roots) both before and after treatment. While there was no difference between the groups pretreatment, the posttreatment buccolingual inclination was significantly greater in the aligner group. In the fixed appliance group, the canines became more upright with treatment, while the buccolingual inclination did not change significantly in the clear aligner group. The intercanine distance did not differ between the groups either before or after treatment. However, it increased significantly over the course of treatment in the aligner group, whereas it did not change significantly in the fixed appliance group.Conclusions:Orthodontic treatment with clear aligners tends to increase the mandibular intercanine distance with little change in inclination in contrast to treatment with fixed appliances, which leaves the intercanine distance unchanged but leads to more upright mandibular canines.     

The relationship between personality traits,pain perception and attitude toward orthodontic treatment

Objective:To investigate the relationship between personality traits and a person''s attitude toward orthodontic treatment and perception of pain during orthodontic treatment.Materials and Methods:The sample consisted of two groups: group 1 consisted of 200 untreated subjects (100 males, 100 females; average age, 21.50 ± 3.35 years), and group 2 consisted of 200 treated subjects (100 males, 100 females; average age, 20.92 ± 2.48 years). The instrument for data collection was a questionnaire that included assessment of patients'' personality profiles, pain expectation for untreated subjects, pain experience for treated subjects, and attitudes toward orthodontic treatment.Results:Gender, treatment status, and personality traits did not affect subjects'' average attitude toward orthodontic treatment, whereas gender was the only variable that affected subjects'' average pain perception (P < .01). The average attitude score in subjects who experienced pain during orthodontic treatment was 5.06 ± 1.43, compared to 4.32 ± 1.35 for subjects who did not experience pain (P < .001). The average pain perception scores in treated subjects with previous knowledge of orthodontic treatment was 5.29 ± 1.94, compared to 6.07 ± 1.95 in subjects who did not have previous knowledge of orthodontic treatment (P < .01).Conclusions:Personality traits did not affect attitude toward orthodontic treatment and pain perception/experience during orthodontic treatment. A more positive attitude was found in patients who experienced less pain during orthodontic treatment.     

Comparison of personality traits,attitude toward orthodontic treatment,and pain perception and experience before and after orthodontic treatment

Objective:To compare personality traits, attitude toward orthodontic treatment, and pain perception and experience before and after orthodontic treatment.Materials and Methods:One hundred subjects (50 male and 50 female) were included in this study. The mean (SD) age was 17.5 (2.05) years at T1 and 19.15 (2.32) years at T2. The instruments for data collection were questionnaires that included assessment of patients'' personality traits, attitudes toward orthodontic treatment, and pain perception/experience. Subjects completed the questionnaires at two different times: before orthodontic treatment (T1) and after fixed orthodontic treatment (T2). Subjects were treated by fixed orthodontic appliances for an average (SD) period of 18.64 (0.35) months. Paired sample t-test and chi-square test were used to detect any differences.Results:Significant changes in personality traits were detected after orthodontic treatment irrespective of gender. Neuroticism, openness, agreeableness, and conscientiousness scores were improved (P < .001). A positive attitude toward orthodontic treatment was reported at T1 (4.31 [±1.26]) and improved at T2 (3.98 [±1.16]) irrespective of gender (P < .05). The average (SD) expected pain score (T1) was 4.73 (1.88) and the average (SD) experienced pain score (T2) was 4.63 (1.58). Significant difference in the expected and experienced pain scores was not detected (P  =  .11).Conclusions:Personality traits and attitude toward orthodontic treatment improved after orthodontic treatment. Reported actual pain experience during orthodontic treatment was similar to that expected before treatment.     

Outcome assessment of lingual and labial appliances compared with cephalometric analysis,peer assessment rating,and objective grading system in Angle Class II extraction cases

Objective:To validate our hypothesis that there would be significant differences in treatment outcomes, including cephalometric values, degree of root resorption, occlusal indices, and functional aspect, between cases treated with labial and lingual appliances.Materials and Methods:Twenty-four consecutively treated Class II cases with extractions and lingual appliance were compared with 25 matched cases treated with extraction and labial appliance. Orthodontic treatment outcomes were evaluated by cephalometric analysis, peer assessment rating, and an objective grading system (OGS). Additionally, functional analysis was also performed in both groups after orthodontic treatment. Statistical comparison was performed using the Wilcoxon signed rank test within the groups, and the Mann-Whitney U-test was used to compare between the labial and lingual groups.Results:The only significant difference between the groups was that the interincisal angle was larger in the lingual group than in the labial group. OGS evaluation showed that control over root angulation was significantly worse in the lingual group than in the labial group. There was no significant difference between groups in the amount of root resorption or in functional evaluation.Conclusions:Generally, lingual appliances offer comparable treatment results to those obtained with labial appliances. However, care should be taken with lingual appliances because they are more prone to produce uprighted incisors and root angulation.     

Comparison of alveolar bone thickness and height after slow expansion using quad-helix or clear aligners

ObjectiveThe study was conducted to investigate the thickness and height of the alveolar bone of individual teeth after slow maxillary expansion (SME) with quad helix or clear aligner appliances and hypothesized that there is no difference in buccal alveolar bone thickness or heights in patients treated by either quad helix or clear aligners.Material and MethodsThis is a retrospective study; the records of 22 patients treated between December 2019 to April 2020 by dental arch expansion using either clear aligners or quad helix appliances were retrieved and studied. The results obtained through cone beam computed tomography (CBCTs) before and immediately after maxillary expansion (2 + 1 mm per side) were analyzed (11 in the Quad Helix group and 11 in the clear aligner). The data collected was analyzed using linear and angular measurements obtained through On-demand 3D App software. Furthermore, Statistical Package for Social Sciences (SPSS) version 25.0 was used to present the findings by mean and standard deviations, and Scheffe’s test was applied for comparing forces.ResultsThe results showed that the mean age of patients in the clear aligner group and Quad Helix was 16.27 ± 0.56 years and 15.5 ± 1.53 years, respectively. There was no difference in buccal alveolar bone thickness or heights in patients treated by either quad helix or clear aligners. This is due to the findings that suggest that there was a decrease in bone height and bone width when treated with a quad helix as compared to clear alignment.ConclusionIt can be concluded that the quad helix SME treatment affects alveolar bone integrity; therefore, clear aligners might be better for treating patients than the quad helix.     

Discomfort associated with Invisalign and traditional brackets: A randomized,prospective trial

Objective:To evaluate differences in discomfort levels between patients treated with aligners and traditional fixed orthodontic appliances.Materials and Methods:This blinded, prospective, randomized equivalence two-arm parallel trial allocated 41 adult Class I nonextraction patients to either traditional fixed appliance (6 males and 12 females) or aligner (11 males and 12 females) treatment. Patients completed daily discomfort diaries following their initial treatment appointment, after 1 month and after 2 months. They recorded their levels of discomfort at rest, while chewing, and while biting, as well as their analgesic consumption and sleep disturbances.Results:Both treatment modalities demonstrated similar levels of initial discomfort. There were no significant sex differences. Patients in the traditional fixed appliances group reported significantly (P < .05) greater discomfort than patients in the aligner group during the first week of active treatment. There was significantly more discomfort while chewing than when at rest. Traditional patients also reported significantly more discomfort than aligner patients after the first and second monthly adjustment appointments. Discomfort after the subsequent adjustments was consistently lower than after the initial bonding or aligner delivery appointments. A higher percentage of patients in the fixed-appliance group reported taking analgesics during the first week for dental pain, but only the difference on day 2 was statistically significant.Conclusions:Patients treated with traditional fixed appliances reported greater discomfort and consumed more analgesics than patients treated with aligners. This trial was not registered.     

Adaptational changes in clear aligner fit with time:: A scanning electron microscopy analysis

ObjectivesTo analyze adaptational changes in clear aligner fit after intraoral usage at different sets of time.Materials and MethodsEight Invisalign appliances (Align Technology, San Jose, California, USA) were collected after intraoral usage. Acrylic imprints of the lower incisor region were constructed for each appliance at T0 (unused appliance). Two appliances were then used intra-orally for each of the following defined periods of time: 3 days, 7 days, 10 days, or 15 days. Used aligners were adapted on its T0 imprint and both were sectioned buccolingually from the distal surfaces of each incisor at the attachment area. Eight surfaces were collected for each set of time (n = 32 surfaces). Microphotographs of obtained sections and micrometric measurements of aligner fit were recorded at five different levels using scanning electron microscopy (SEM). Mean values of the fit changes (gap width) and group comparisons were statistically analyzed using analysis of variance and Tukey''s post hoc tests. Significance level was set at P < .05.ResultsHighly significant differences in aligner fit were found at the different time points assessed (P < .001) with the least mean gap width at 15 days (176 ± 98 μm) and the highest at 7 days (269 ± 145 μm). Significant differences in aligner fit at different attachment levels were also found (P < .01) with the least mean gap width at the middle of the labial surface of the attachment (187 ± 118 μm).ConclusionsThe 15-day period of intraoral aligner wear might still be recommended as it showed the best adaptation and least gap width between the aligner and the attachment.     

三种矫治器治疗安氏Ⅱ类2分类对切牙牙根吸收的影响

目的 比较不同矫治器治疗安氏Ⅱ类2分类错牙合畸形患者切牙牙根的吸收状况。方法 选择使用不同矫治器的安氏Ⅱ类2分类成年患者30例,其中传统MBT托槽、自锁托槽以及无托槽隐形矫治器的患者各10例,共计240颗切牙。收集患者治疗前后的锥形束CT(CBCT)影像学资料,并导入Dolphin Imaging软件,Mimics软件以及3-Matics软件测量分析治疗前后切牙牙根吸收情况。结果 传统MBT托槽组和自锁托槽组的上下颌中切牙以及侧切牙的牙齿长度(L)与无托槽隐形矫治器组上下颌中切牙及上颌侧切牙的牙齿长度治疗后较治疗前显著减小,差异具有统计学意义。使用无托槽隐形矫治器的患者下颌侧切牙治疗前后的牙齿长度无显著变化。而三组之间的对比,上下颌中切牙牙齿长度变化无显著统计学差异。无托槽隐形矫治器组上下颌侧切牙的牙齿长度减少量相对更低,差异具有统计学意义(P＜0.05)。此外,无托槽隐形矫治器组平均牙齿长度变化为(-0.37±0.11)mm,显著小于传统MBT托槽组(-1.32±0.47)mm及自锁托槽组(-1.05±0.38)mm。在牙根吸收区域的比较上,各组均表现为腭侧吸收多于唇侧吸收,近中吸收多于远中吸收。结论 无托槽隐形矫治器治疗安氏Ⅱ类2分类错牙合畸形可有效降低切牙牙根吸收严重程度。     

Lingual orthodontics: Understanding the issues is the key to success with lingual mechanics

Clear aligners disrupted the orthodontic marketplace almost twenty years ago.¹ The result of this disruption has been a significant increase in the demand for adult esthetic orthodontic treatment.2., 3. Today, we are in the midst of another disruption in orthodontics; direct to patient orthodontic care. Direct to patient care is a result of the evolution of digital orthodontics, which has led to the development of custom orthodontic appliances. Besides the disruption of the orthodontic marketplace, custom appliances also offer an opportunity to add value to the care that we offer our patients through the development of appliances systems that are superior in esthetics and in certain circumstances offer biomechanical advantages⁴ In this paper, we will present issues related successful lingual mechanics, one of the custom appliance opportunities available to us that add value to the care we offer our patients. We will consider the problem associated with lingual mechanics and the solutions offered by custom lingual appliance systems.     

隐形矫治器对患者龈沟液中AST和ALP水平的影响

目的:探讨无托槽隐形矫治器与固定矫治器对正畸患者龈沟液中天门冬氨酸转氨酶(AST)和碱性磷酸酶(ALP)水平的影响。方法:选取16~35岁正畸患者30例,随机分为两组,每组各15例。实验组采用隐形矫治器,对照组采用直丝弓固定矫治器。分别在治疗前和治疗后6个月,检测各组患者菌斑指数(PLI)、牙龈指数(GI)和探诊深度(PD);收集患者龈沟液,检测AST、ALP水平。结果:矫治后6个月,实验组患者牙周指数、AST、ALP水平均明显低于对照组,差异具有统计学意义(P<0.05)。结论:观察期内,隐形矫治器较固定矫治器更有利于维护患者牙周健康。     

Status of lingual orthodontics

The lingual appliance was developed simultaneously in 2 countries during the 1970s. Although not fully recognized by the orthodontic mainstream, lingual treatment has steadily expanded, with increased numbers of lingual orthodontists and patients. This article reviews the development, advantages and disadvantages, bonding techniques, biomechanics, and treatment procedures of the lingual appliance. Currently, there are few contraindications for treatment with the lingual appliance. Cephalometric measurements do not reveal statistically significant differences in treatment results between labial and lingual treatment; however, more clinical trial studies are needed to compare the efficiency and outcome of lingual appliances with those of labial appliances.     

Effects of fixed labial orthodontic appliances on speech sound production

Objective:To explore the impact of fixed labial orthodontic appliances on speech sound production.Materials and Methods:Speech evaluations were performed on 23 patients with fixed labial appliances. Evaluations were performed immediately prior to appliance insertion, immediately following insertion, and 1 and 2 months post insertion. Baseline dental/skeletal variables were correlated with the ability to accommodate the presence of the appliances.Results:Appliance effects were variable: 44% of the subjects were unaffected, 39% were temporarily affected but adapted within 2 months, and 17% of patients showed persistent sound errors at 2 months. Resolution of acquired sound errors was noted by 8 months post–appliance removal. Maladaptation to appliances was correlated to severity of malocclusion as determined by the Grainger’s Treatment Priority Index. Sibilant sounds, most notably /s/, were affected most often.Conclusions:(1) Insertion of fixed labial appliances has an effect on speech sound production. (2) Sibilant and stopped sounds are affected, with /s/ being affected most often. (3) Accommodation to fixed appliances depends on the severity of malocclusion.     

Cephalometric comparison of adult anterior open bite treatment using clear aligners and fixed appliances

Objectives:To compare fixed appliances and clear aligner therapy in correcting anterior open bite and in controlling the vertical dimension in adult patients with hyperdivergent skeletal patterns.Materials and Methods:In this retrospective study, two treatment groups of adult (≥18 years old) hyperdivergent patients (mandibular plane angles of ≥38°) with anterior open bites were included: 17 fixed appliance patients and 36 clear aligner patients. Thirteen cephalometric measurements representing the vertical dimension were reported for each group. A two-sample t-test was used to assess differences in changes in mandibular plane angle and overbite between the two treatment groups.Results:There were no statistical differences found in the magnitude of overbite correction and the changes in any of the cephalometric measurements for vertical control. The clear aligner group showed a slightly greater amount of lower incisor extrusion (P = .009). The main mechanism of open bite correction was similar between the two treatment groups and was accomplished through retroclination of the upper and lower incisors while maintaining the vertical position of the upper and lower molars.Conclusions:Cephalometric comparison of anterior open bite correction and changes in the mandibular plane angle associated with use of clear aligners and fixed appliances did not demonstrate statistically significant differences in adult hyperdivergent patients.