Labial Movement Research Articles

Clear aligners for patients with severe gingival recession: A case report

Fixed appliances are an excellent treatment approach for mild to severe malocclusions. Increasingly, aligner-based treatments are being provided as a treatment option. The latter may be preferable to fixed appliances in selected cases. A young adult with severe gingival recession is presented who was treated successfully with aligner-based treatment with minimal deterioration of the gingival tissue levels. However, limits should be applied to the buccal and labial movement of teeth to reduce the risk of worsening of the gingival recession. CPD/Clinical Relevance: Aligner-based treatment may be preferable for orthodontic patients with severe gingival recession.

Reference points to evaluate changes in the upper lip after labial incisor movement between tipping and translation in crowding patients: A retrospective study

ObjectiveThis study aimed to compare the changes of reference points on the labial surface of upper incisors (U1) to upper lip (UL) after U1 labial movement between a translation group (TSL) and tipping group (TIP). Correlations between changes in U1 and UL were determined. MethodsLateral cephalometric radiographs were selected and divided into TSL and TIP groups by pre- and post-treatment superimpositions. Skeletal, dental, and soft tissue of pre- and post-treatment treatment and variables were evaluated. Independent t-test and Wilcoxson test were applied for the statistical analysis between TSL and TIP. Spearman’s correlation coefficients and multiple linear regression analysis were used to verify the association between lip profile changes and other variables in TSL and TIP group separately. ResultsAfter U1 labial movement, the incisal edge (LaU1e), middle (LaU1m), and cervical (LaU1c) points of TSL moved evenly labially, whereas the TIP group had incisal edge that moved greater labially than the middle and cervical points. UL moved more labially in TSL (0.87–1.05 mm) than the TIP (0.31–0.41 mm). UL changes to the E-line in TSL showed significant positive correlations to all three LaU1(e, m, c)-SnTV changes. In the TIP group, only a positive correlation presented for the LaU1m-SnTV and LaU1c-SnTV changes. Nevertheless, Multiple linear regression analysis indicated the unfeasibility of predicting the upper lip changing ConclusionLaU1e in TSL and TIP moved almost equally labially but less labially in TIP at the middle and cervical points. The UL moved more labially in TSL than TIP. Rather than using the incisal edge to estimate upper lip changes, it would be better to use the middle and cervical points of U1, which coincide with Labrale superioris (Ls).

A preliminary investigation into the impact of soft tissue augmentation-based periodontal phenotype modification therapy for patients exhibiting class III decompensation

BackgroundPatients with skeletal angle Class III malocclusion usually have inadequate hard and soft tissue volume at the mandibular anterior teeth. The labial proclination at the teeth may lead to gingival recession. The purpose of this study was to explore whether periodontal phenotype modification therapy with soft tissue augmentation (PhMT-s) can prevent gingival recession in these patients.MethodsFour patients with skeletal Class III malocclusion and a thin periodontal phenotype underwent surgical-orthodontic treatment. Prior to tooth movement, they underwent a minimally invasive vestibular incision with subperiosteal tunnel access combined with autogenous connective tissue grafts for periodontal phenotype modification with soft tissue augmentation (PhMT-s). The labial gingival thickness of the anterior mandibular teeth was measured at three distinct levels: at the cementoenamel junction (GT0), 3 mm apical to the CEJ (GT3), and 6 mm apical to the CEJ (GT6). These measurements were taken at baseline, three months following PhMT-s, and after tooth decompensation. Additionally, a biopsy sample was obtained from the PhMT-s site of one patient. All sections were subsequently stained using hematoxylin and eosin, Masson trichrome, Sirius Red, and immunohistochemistry.ResultsThe thickness of the labial gingiva was increased about 0.42 to 2.00 mm after PhMT-s. At the end of pre-orthognathic surgical orthodontic treatment, the thickness of the labial gingiva was increased about − 0.14 to 1.32 mm compared to the baseline and no gingival recession occurred after the pre-orthognathic surgical orthodontic treatment. The histologic results demonstrated that the grafts obtained from the PhMT-s site exhibited increased deposition of collagen fibers. Moreover, the proportion of type III collagen increased and the grafts displayed significantly reduced positive expression of CD31 and OCN.ConclusionsPhMT-s increased the thickness of the soft tissue, stabilizing the gingival margin for teeth exhibiting a thin periodontal phenotype and undergoing labial movement. This is attributed to the increased deposition of collagen fibers.

Tooth movement analysis of maxillary dentition distalization using clear aligners with buccal and palatal mini-screw anchorages: A finite element study.

To assess the tooth movement trends during the three stages of maxillary dentition distalization with clear aligners (CA) and to compare the efficacy of different mini-screw anchorage systems. Three-dimensional (3D) finite element models of three anchorage systems (A, control group; B, buccal mini-screw anchorage group; C, palatal mini-screw anchorage group) were established. Three stages of simulating maxillary dentition distalization with CA included maxillary molar distalization (stage 1), maxillary premolar distalization (stage 2) and maxillary anterior teeth retraction (stage 3). Therefore, a total of nine models were constructed to analyse the 3D displacement of maxillary teeth during the distalization process. The displacement pattern of maxillary dentition during distalization was similar across the three groups, but with varying magnitudes. During stage 1, groups B and C exhibited greater amounts of molar distalization compared to group A. Group C also demonstrated the least amount of labial movement of the maxillary central incisor compared to the other two groups. During stage 2, the mesial displacement of the maxillary first molar was less significant in groups B and C than in group A. In the final stage, group C exhibited a greater amount of maxillary anterior retraction compared to groups A and B. The palatal mini-screw anchorage system was effective in reducing anchorage loss and improving the efficacy of maxillary dentition distalization with CA.

Three-dimensional analysis of the positional relationship between the dentition and basal bone region in patients with skeletal Class I and Class II malocclusion with mandibular retrusion.

This study aimed to determine the maxillary and mandibular basal bone regions and explore the three-dimensional positional relationship between the dentition and basal bone regions in patients with skeletal Class I and Class II malocclusions with mandibular retrusion. Eighty patients (40 each with Class I and Class II malocclusion) were enrolled. Maxillary and mandibular basal bone regions were determined using cone-beam computed tomography images. To measure the relationship between the dentition and basal bone region, the root position and root inclination were calculated using the coordinates of specific fixed points by a computer program written in Python. In the Class II group, the mandibular anterior teeth inclined more labially (P < 0.05), with their apices positioned closer to the external boundary. The apex of the maxillary anterior root was positioned closer to the external boundary in both groups. Considering the molar region, the maxillary first molars tended to be more lingually inclined in females (P = 0.037), whereas the mandibular first molars were significantly more labially inclined in the Class II group (P < 0.05). Mandibular anterior teeth in Class II malocclusion exhibit a compensatory labial inclination trend with the crown and apex relative to the basal bone region when mandibular retrusion occurs. Moreover, as the root apices of the maxillary anterior teeth are much closer to the labial side in Class I and Class II malocclusion, the range of movement at the root apex should be limited to avoid extensive labial movement.

Bedside Clinical Swallow Test and the Fiberoptic Endoscopic Evaluation of Swallow - Level of Agreement.

Bedside test are important tool for evaluating aspiration during swallowing. FEES that is functional endoscopic evaluation of swallowing is a gold standard method used in evaluation of dysphagia patients. Through this study we aim to assess the sensitivity and specificity of Bedside Clinical swallow evaluation in comparison with Fiberoptic Endoscopic Evaluation of Swallowing. To analyze which physiological examination amongst oro motor labial examination, lingual examination, gag reflex, coughs during or post swallow, change in voice quality and hyo-laryngeal excursion during swallow with semisolid and thin liquid consistency in the Bedside Clinical swallow evaluation is better indicator for presence or absence of aspiration. 38 patients with different diagnostic entities were presented& included in the study for the assessment of swallowing difficulties as presence or absence of aspiration and possibility of weaning from nasogastric or Nasojejunal tube between March 2016 to October 2016. They were 32 (86%) males and 6 (14%) females. Aspiration correlates were assessed using bedside test (labial movement, lingual movement, gag reflex, strength of productive cough, hyo-laryngeal excursion, And post swallow changes in the quality of voice). FEES was then performed and sensitivity and specificity was compared. Bedside test showed 84.62% sensitivity and 100% specificity in comparison to FEES. Gag and voice quality were noted to have significant difference with value of 0.009 and 0.033 respectively. Bedside tests can be considered as an important, easy, sensitive, and specific for the detection of aspiration. Combination of gag reflex and change of voice as parameters of aspiration compared with FEES showed high sensitivity and specificity.

Comparison of posttreatment stability after total mandibular arch distalization with mini-implants and mandibular setback surgery.

To compare posttreatment stability in skeletal Class III patients between those treated by total mandibular arch distalization (TMAD) with buccal mini-implants and those by mandibular setback surgery (MSS). The samples included 40 Class III adults, 20 treated by TMAD using buccal interradicular mini-implants and 20 treated with MSS. Lateral cephalograms were taken at pretreatment, posttreatment, and at least 1-year follow-up, and 24 variables were compared using statistical analysis. Mandibular first molars moved distally 1.9 mm with intrusion of 1.1 mm after treatment in the TMAD group. The mandibular incisors moved distally by 2.3 mm. The MSS group exhibited a significant skeletal change of the mandible, whereas the TMAD group did not. During retention, there were no skeletal or dental changes other than 0.6 mm labial movement of the mandibular incisors (P < .05) in the MSS group. There was 1.4° of mesial tipping (P < .01) and 0.4 mm of mesial movement of the mandibular molars and 1.9° of labial tipping (P < .001) and 0.8 mm of mesial movement of the mandibular incisors in the TMAD group. These dental changes were not significantly different between the two groups. The TMAD group showed a slightly decreased overjet with labial tipping of the mandibular incisors and mesial tipping of the first molars during retention. Posttreatment stability of the mandibular dentition was not significantly different between the groups. It can be useful to plan camouflage treatment by TMAD with mini-implants in mild-to-moderate Class III patients.

Long-term bone remodeling of maxillary anterior teeth with post-treatment alveolar bone defect in adult patients with maxillary protrusion: a prospective follow-up study

BackgroundAlveolar bone defects, particularly palatal bone dehiscence (PBD) and labial bone fenestration (LBF), occur frequently as a result of retraction of the maxillary anterior teeth. The study aims to explore the long-term bone remodeling of maxillary anterior teeth in adult patients with post-orthodontic treatment PBD and LBF.Materials and methodsThe study includes 24 adult patients with maxillary protrusion (8 males, 16 females) who were treated with extraction of four first premolars and had alveolar bone defects (PBD or LBF) in maxillary anterior teeth following orthodontic treatment. Cone-beam computed tomography imaging measurements were obtained before (T1), after (T2) orthodontic treatment, and after at least 1-year removable thermoplastic retainer retention (T3). The maxillary anterior teeth with PBD or LBF at T2 were divided into the PBD or LBF groups, respectively. The labial and palatal alveolar bone height (ABH), alveolar bone thickness (ABT), and movement of maxillary anterior teeth were measured during retraction (T2–T1) and retention (T3–T2) periods.ResultsThe incidence of PBD and LBF in maxillary anterior teeth significantly increased after orthodontic treatment and decreased during the retention period. In the PBD group, the palatal ABH of all maxillary anterior teeth significantly increased from T1 to T2 but decreased from T2 to T3. The ABT of the maxillary central incisor and canine significantly increased on the palatal side and decreased on the labial side during the retention period. In the LBF group, the labial ABT of the maxillary central incisor at the apical level showed a significant decrease from T1 to T2, followed by an increase from T2 to T3. In both groups, the maxillary central incisor showed significant labial movement, with a relative intrusion during the retention period.ConclusionFor adult patients with maxillary protrusion, the alveolar bone defect of maxillary anterior teeth caused by orthodontic retraction significantly improved during the retention period, indicating good long-term bone remodeling. Our findings suggest that a combination of spontaneous reorientation of maxillary anterior teeth and bone remodeling contributed to alveolar bone covering in these patients.

The association between longitudinal declines in speech sound accuracy and speech intelligibility in speakers with amyotrophic lateral sclerosis

ABSTRACT The purpose of this study was to examine how neurodegeneration secondary to amyotrophic lateral sclerosis (ALS) impacts speech sound accuracy over time and how speech sound accuracy, in turn, is related to speech intelligibility. Twenty-one participants with ALS read the Bamboo Passage over multiple data collection sessions across several months. Phonemic and orthographic transcriptions were completed for all speech samples. The percentage of phonemes accurately produced was calculated across each phoneme, sound class (i.e. consonants versus vowels), and distinctive feature (i.e. features involved in Manner of Articulation, Place of Articulation, Laryngeal Voicing, Tongue Height, and Tongue Advancement). Intelligibility was determined by calculating the percentage of words correctly transcribed orthographically by naive listeners. Linear mixed effects models were conducted to assess the decline of each distinctive feature over time and its impact on intelligibility. The results demonstrated that overall phonemic production accuracy had a nonlinear relationship with speech intelligibility and that a subset of features (i.e. those dependent on precise lingual and labial constriction and/or extensive lingual and labial movement) were more important for intelligibility and were more impacted over time than other features. Furthermore, findings revealed that consonants were more strongly associated with intelligibility than vowels, but consonants did not significantly differ from vowels in their decline over time. These findings have the potential to (1) strengthen mechanistic understanding of the physiological constraints imposed by neuronal degeneration on speech production and (2) inform the timing and selection of treatment and assessment targets for individuals with ALS.

An in vitro evaluation of aligner force decay in artificial saliva

Background/purposeThe present study aimed to compare the force decay of invisible aligners for maxillary anterior teeth with 0.1 mm (D1), 0.2 mm (D2), and 0.3 mm (D3) labial movement within a simulated oral environment over 7 days. Materials and methodsThe prepared invisible aligners were immersed in saliva (S) and subjected to applied force (F) for 7 days. The aligners were set and placed on the maxillary right central incisor with 0.1 mm (D1), 0.2 mm (D2), and 0.3 mm (D3) labial movement. Thin-film pressure sensors were used to measure the aligner force changes. The data were collected and analyzed by statistical methods. ResultsSignificant differences were observed in the initial and first-day force between the D2 and D3 groups under simulated oral environment force (SF) (P < 0.05). There was a significant difference in force decay between Day 1 and Day 7 for all groups (P < 0.05). The SFD1 group showed a significant decrease in force on Day 5 (P < 0.05), while the SFD2 and SFD3 groups showed significant force decay on Day 4 (P < 0.05). The force decay ratio on Day 7 was higher in the SFD3 group than in the SFD1 and SFD2 groups, but no significant difference was observed. ConclusionLarger labial movement of the aligners resulted in higher force decay under artificial saliva environments, and the force decay of invisible aligners was increased by immersion time in artificial saliva.

Morphological changes in alveolar bone thickness and height after orthodontic proclination or labial movement combined with autogenous soft tissue grafting: a CBCT evaluation

BackgroundAutogenous soft tissue grafting is indicated in thin gingival biotypes before orthodontic proclination or labial movements to increase the keratinized gingiva and prevent gingival recession. However, its effect on local alveolar bone remodeling is unclear. The aim of this study was to investigate the effects of autogenous soft tissue grafting on local alveolar bone after orthodontic proclination or labial movements.MethodsSixteen patients with a thin scalloped gingival biotype, narrow keratinized gingiva, or thin cortical bone requiring orthodontic proclination or labial movement of teeth were included. Cone-beam computed tomography (CBCT) images were obtained before grafting and at least 6 months after surgery. Sixty mandibular teeth were included, and the vertical bone level and horizontal labial bone thickness were measured. The results were compared using paired t-tests or Wilcoxon signed-rank test.ResultsThe horizontal labial bone thickness increased, especially at 6 mm below the cementoenamel junction (CEJ) in the mandibular central and lateral incisors (P < 0.05). The total alveolar bone area of the canines, first premolars, and second premolars increased at 3, 6, and 9 mm below the CEJ, respectively, and the differences were statistically significant (P < 0.05). Additionally, vertical bone height increased minimally on the labial side, but the differences were not statistically significant (P > 0.05).ConclusionsNew bone regeneration was observed on the labial (pressure) side after autogenous soft tissue grafting, which may represent a mechanism to effectively prevent gingival recession and maintain periodontal health.IRB approvalAll the experimental procedures involving humans in this study were approved by the Medical Ethics Committee of Xiangya Stomatological Hospital, Central South University ( No. 20190048).

Effectiveness of clear aligners in achieving proclination and intrusion of incisors among Class II division 2 patients: a multivariate analysis

BackgroundThe predictability of incisor movement achieved by clear aligners among Class II division 2 patients is poorly understood. The aim of this retrospective study was to determine the effectiveness of clear aligners in proclining and intruding upper incisors and its influencing factors.MethodsEligible patients with Class II division 2 malocclusion were included. For clear aligner therapy, three types of incisor movements were designed: proclination, intrusion and labial movement. Pre-treatment and post-treatment dental models were superimposed. The differences between predicted and actual (DPA) tooth movement of incisors were analyzed. Univariate and multivariate linear regression were used to analyze the potential influencing factors.ResultsA total of 51 patients and their 173 upper incisors were included. Actual incisor proclination and intrusion were less than predicted ones (both P < 0.001), while actual labial movement was greater than predicted one (P < 0.001). Predictability of incisor proclination and intrusion was 69.8% and 53.3%, respectively. Multivariate linear regression revealed that DPA of proclination was significantly positively associated with predicted proclination (B = 0.174, P < 0.001), ipsilateral premolar extraction (B = 2.773, P < 0.001) and ipsilateral canine proclination (B = 1.811, P < 0.05), while negatively associated with molar distalization (B = − 2.085, P < 0.05). The DPA of intrusion was significantly positively correlated with predicted intrusion (B = 0.556, P < 0.001) while negatively associated with labial mini-implants (B = − 1.466, P < 0.001). The DPA of labial movement was significantly positively associated with predicted labial movement (B = 0.481, P < 0.001), while negatively correlated with molar distalization (B = − 1.004, P < 0.001), labial mini-implants (B = − 0.738, P < 0.001) and age (B = − 0.486, P < 0.05).ConclusionsFor Class II division 2 patients, predicted incisor proclination (69.8%) and intrusion (53.3%) are partially achieved with clear aligner therapy. Excessive labial movement (0.7 mm) of incisors may be achieved. Incisor movement is influenced by predicted movement amount, premolar extraction, canine proclination, molar distalization, mini-implants and age.

Maxillary molar distalization with a 2-week clear aligner protocol in patients with Class II malocclusion: A retrospective study

This study aimed to investigate the efficacy of molar distalization with or without anterior teeth retraction. Forty-three patients who received maxillary molar distalization with clear aligners were retrospectively enrolled and further divided into 2 groups: a retraction group (with maxillary incisor retraction ≥2 mm in ClinCheck) and a nonretraction group (without anteroposterior movement or with the labial movement of the maxillary incisor in ClinCheck). Pretreatment and posttreatment models were collected and laser-scanned to obtain the virtual models. Three-dimensional digital assessments of molar movement, anterior retraction and arch width were analyzed in the reverse engineering software Rapidform 2006. To calculate the efficacy of tooth movement, the achieved tooth movement assessed on the virtual model was compared with the predicted tooth movement in ClinCheck. The achieved efficacy rates of molar distalization for the maxillary first and second molars were 36.48% and 41.94%, respectively. There was a significant difference in molar distalization efficacy between the retraction group (31.50% at the first molar and 35.63% at the second molar) and the nonretraction group (48.14% at the first molar and 52.51% at the second molar). In the retraction group, the efficacy of incisor retraction was 56.10%. The efficacy of dental arch expansion was more than 100% at the first molar levels in the retraction group and at the second premolar and first molar levels in the nonretraction group. There is a discrepancy between the outcome and the predicted maxillary molar distalization with clear aligners. The efficacy of molar distalization with clear aligners was significantly affected by anterior teeth retraction, and the arch width significantly increased at the premolar and molar levels.

Comparative evaluation of variations in torque expression in maxillary incisor and canine using different bracket prescriptions placed at different crown levels by finite element (FE) method: An in-vitro analysis.

While using preadjusted brackets, the position of the bracket on the crown is one of the deciding factors that determine the tooth's final tip, torque, height, and rotation. The final tooth position is not optimal if the bracket is placed incorrectly or if the varying crown morphology does not correspond with the bracket design. The present study was conducted to evaluate and compare the variations in torque expression in maxillary incisor and canine using different bracket prescriptions placed at different crown levels by finite element method. For the present study, three-dimensional models of maxillary right central incisor and canine were made using CREO version 4.0 software. CREO is a powerful three-dimensional (3-D) computer-based, computer-aided design (CAD) software developed by Parametric Technology Corporation (PTC) to aid in design processes. Simulation was done to replicate the clinical situation of an active palatal root torque acting on the incisor and canine. The induced palatal movement of root tips and labial movement of crowns tips, overall stress, and von Mises stress generated in the brackets and the total equivalent strains developed in the periodontal ligament (PDL) were calculated, while the values obtained were tabulated and subjected to statistical analysis. Based on the findings of the present study, the average maximum stress produced in the bracket was calculated as 265.069 Mpa in incisor and 166.742 Mpa in the canine. Likewise, the average of the maximum displacement of root apex observed in the present study was calculated as 0.01401 mm in the incisor and 0.00421 mm in the canine, while the average strain developed in the PDL was calculated as 0.0587 for incisor and 0.0498 for the canine. Furthermore, it was, also, observed that the magnitude of strain developed in the PDL increased with increase in the stress produced by the bracket prescription for both incisor and canine. Within the limitations of the present study, it was concluded that the magnitude of displacement of root apex was significantly influenced by bracket prescription and bracket position. Also, the stress developed in the bracket was influenced by bracket prescription and position, while the variation in crown morphology in the incisor and canine played a significant role in the eventual strain developed in the PDL after torque application.

Mandibular incisor inclination and gingival recession after treatment with the Jasper Jumper: a 10-year follow-up

ObjectiveTo evaluate the long-term outcomes of Class II treatment with the Jasper Jumper appliance and comprehensive orthodontic treatment concerning inclination of the mandibular incisors and gingival recession.MethodsSixteen patients with Class II malocclusion at a mean age of 12.54y (SD = 1.17) were treated with the Jasper Jumper appliance and comprehensive orthodontic treatment. The mean treatment time was 2.05y (SD = 0.21). Dental records were taken before (T1), after treatment (T2) and 11.90y (SD = 0.48) after debonding (T3). The frequency of gingival recession, clinical crown height and mandibular incisor position were evaluated using intraoral photographs, digital models and lateral cephalograms. Interphase changes were evaluated using dependent t and McNemar’s tests. Correlation between clinical crown height and final position of the mandibular incisors was evaluated using Pearson correlation test (P < 0.05).ResultsThe frequency of gingival recessions increased over time and was observed in 6 (9.4%), 12 (18.8%) and 24 (37.5%) of the mandibular incisors at T1, T2 and T3, respectively. A significant increase in labial inclination and protrusion of the mandibular incisors was observed between T1 and T2 interval. The clinical crown height significantly increased in the follow-up period (T3–T2) and in the complete observation time (T3–T1). There was no correlation between the amount of labial inclination and protrusion of the mandibular incisors and clinical crown height for all time intervals.ConclusionNo significant correlation between the amount of labial movement of the mandibular incisor and clinical crown height increase was found.

Long-term periodontal changes associated with oral appliance treatment of obstructive sleep apnea.

To characterize the mandibular anterior teeth crown height as a marker of periodontal changes and bone loss as a side effect of an oral appliance worn for a minimum of 4.5 years. This retrospective study conducted in patients with healthy baseline periodontium recruited participants among consecutive sleep apnea patients treated with an oral appliance between 2004 to 2014. Eligible participants were recalled for a follow-up visit at which a periodontal examination was performed and a lateral cephalogram and dental impressions were obtained. Clinical crown height for mandibular anterior teeth and cephalometric variables were measured and compared before and after treatment. A full periodontal evaluation was performed at the follow-up visit. Twenty-one patients enrolled with a mean treatment length of 7.9 ± 3.3 years. For the mandibular anterior teeth, clinical crown height did not change over the evaluated period. At follow-up, all the periodontal assessed variables were within normal limits, with the mean probing depth of 1.4 ± 0.5 mm, recession 0.6 ± 1.1 mm, and clinical attachment loss 0.8 ± 1.0 mm. Compared with baseline, there was a significant proclination of mandibular incisors (mean increase of 5.1 degrees) with the continued use of an oral appliance. Gingival levels were maintained with clinically insignificant changes during the observation period. Inclination of the mandibular incisors increases significantly with the use of an oral appliance in patients with obstructive sleep apnea. Positional changes in these teeth were not associated with any measured evidence of increase in clinical crown height or gingival recession. Heda P, Alalola B, Almeida FR, Kim H, Peres BU, Pliska BT. Long-term periodontal changes associated with oral appliance treatment of obstructive sleep apnea. J Clin Sleep Med. 2021;17(10):2067-2074.

A cone-beam computed tomographic study evaluating the efficacy of incisor movement with clear aligners: Assessment of incisor pure tipping, controlled tipping, translation, and torque

This retrospective clinical study aimed to evaluate the efficacy of different types of incisor movementswith clear aligners in the sagittal plane. Pretreatment and posttreatment cone-beam computed tomography (CBCT) scans were collected from 69 patients who underwent nonextraction treatment with clear aligners (Invisalign; Align Technology, San Jose, Calif). Integrated 3-dimensional models of the virtual incisor position (ClinCheck; Align Technology) and the posttreatment incisor position (from posttreatment CBCT scans) were superimposed over the pretreatment position (from pretreatment CBCT scans) using Mimics software (Materialise, Leuven, Belgium). On the basis of the location of the rotation center, incisors showing pure tipping (>10°), controlled tipping (>10°), translation (>1mm), or torque (>10°) movements were selected. Efficacy was determined by comparing the predicted and achieved incisor movement, and differences with efficacy were analyzed using Kruskal-Wallis and Shapiro-Wilk tests (α=0.05). In measurements for 231 incisors, the mean efficacy of incisor movements in the sagittal plane was 55.58%. The most and least predictable movements were pure tipping (72.48%) and torque (35.21%), respectively. Labial root movement was significantly more predictable than lingual root movement, and labial movement of the mandibular incisors was significantly easier than that of the maxillary incisors. The type of tooth movement achieved was different from the type designed. The efficacy of incisor movement in the sagittal plane using clear aligners varies with designed movement type, and labial root movement appears to be more accurate than the lingual root movement. The biomechanics of clear aligners remains to be further elucidated to achieve more predictable treatment results.

Mandibular propulsion appliance for adults with Class II malocclusion: a systematic review and meta-analysis.

The effects of mandibular propulsion appliances in adults have some controversial results. While some authors claim that its use in non-growing patients could produce some dentoskeletal effects, other studies indicate that Class II correction occurs only through significant dental effects. To evaluate the effects in non-growing Class II patients with mandibular retrusion, promoted by the treatment with mandibular propulsion appliances and determine if they produce mandibular changes. The research was carried out in nine electronic databases and additional manual searches up to July 2019. Selection criteria were no restriction was placed on date and publication language. Randomized or non-randomized clinical trials with/without control were included. They must evaluated non-growing patients with Class II malocclusion, treated with mandibular propulsion appliances; outcomes were assessed before and after treatment. Data were extracted by two independent examiners in duplicate. The ROBINS-I tool was used to assess the methodological quality of the included studies. Of the 2824 articles identified, 11 non-randomized clinical articles were selected for qualitative analysis and 8 for quantitative analysis. SNB (0.87°, CI 95% 0.08, 1.66), ANB (-0.82°, CI 95% -1.24 to 0.40) and Pg/OLp [2.3 to 1.2 mm (P < 0.001)] presented smallest but significant mandibular changes with some differences regarding the used appliance. The Herbst appliance showed the largest mandibular changes followed by the SUS appliance when evaluated through Ar-Pg. SNA showed non-significant changes. Overbite (-2.85. CI 95% -3.06, -2.64), Overjet (-5.00.CI 95% -5.45, -4.55) showed significant changes in all devices. Class II correction occurs through a significant labial movement of the mandibular incisors, some lingual inclination of the maxillary incisors and minor skeletal changes. All mandibular propulsion appliances examined, showed efficiency in normalizing the Class II malocclusion in adult patients; however, changes were acquired mainly through dentoalveolar changes. Some minor mandibular forward changes was noted, mainly in patients treated with the Herbst appliance. Randomized clinical trials are needed to improve scientific evidence. PROSPERO (code CRD42017067384).

Clinical effect of bone-anchored pendulum in treatment for class II malocclusion

Objective To study the clinical effect of bone-anchored pendulum in treatment for class Ⅱ malocclusion. Methods Twelve patients treated by bone-anchored pendulum were chosen. In each patient, two microscrews were inserted in the anterior paramedian region of the median palatal suture, 6-9 mm posterior to the incisive foramen and 3–6 mm lateral to the median line. Pendulum that based on the microscrews was used to distalize maxillary first molar, and the force applied was 250 g. Skeletal and dental changes were measured on cephalograms before (T1) and after (T2) distalization. Results Class Ⅰ molar relationship had been obtained 7 month after distalization. The average distal movement of the maxillary first molars was 7.07 mm, and the inclination was 9.93°. The second premolars were distalized an average of 5.44 mm with inclinations of 5.22°. The first premolars were distalized an average of 4.09 mm with inclinations of 3.95°. The maxillary anterior teeth were retruded 0.93 mm and palatally inclined 1.66°. There was statistical difference in that change. Conclusions By the use of microscrew, pendulum can distalize maxillary molar effectively without mesial movement of premolar and labial movement of incisor, and no loss of dental anchorage is observed during the distal movement. Key words: Malocclusion, Angle Class Ⅱ; Orthotic Devices; Dental implantation; Bone-anchored pendulum

Gummy smile: diagnosis and treatment options

Background: An harmonic smile should show the whole extension of incisors, canines and pre molars and has a slight touch of those teeth on the lower lip with the incisal edge curvature parallel to the inner lower lip curvature. However the dentist can deal with smiles that differ from this parameter, presenting disproportion between the smile components: tooth, gum and upper lip. The gummy smile diagnosis happens when there is 3 mm or more gingival tissue in smile, being a commonly complaint in dental offices. There are five etiologies for this condition described in the literature: extrusion of the upper-anterior teeth, upper alveolar protrusion, altered passive eruption, excess of labial movement / short lip and vertical maxillary excess. Thus it has a plenty etiologies, its necessary that the oral and maxillo surgeon perform a correct diagnosis offering the best treatment for each case.