Dental, skeletal and soft tissue changes after bimaxillary protrusion treatment with temporary anchorage devices using different retraction mechanics

BACKGROUND

Temporary anchorage devices (TADs), which are absolute anchorage, are used for retraction of the anterior teeth in cases of severe bimaxillary protrusion. There have been a number of studies regarding anterior tooth movement using TADs performed by simulation systems and actual treated materials with sliding mechanics. However, there are few studies regarding anterior tooth movement using TADs treated by loop mechanics The purpose of this study was to investigate the effect of TADs in anterior tooth movement using loop mechanics performed in actual cases of bimaxillary protrusion.

METHODS

This study was performed in 20 adult patients with severe bimaxillary protrusion treated with four bicuspid extraction with sliding or loop mechanics (n = 10 in each mechanics) using TADs. The skeletal and denture patterns, as well as the soft tissue profile from pre-treatment (T0) and post-treatment (T1) lateral cephalograms, were compared between sliding and closing loop mechanics.

RESULTS

The use of TADs is useful for retraction of anterior teeth without molar anchorage loss. in sliding and loop mechanics. The upper anterior teeth were less lingual tipped and lower anterior teeth were more upright resulting in less clockwise rotation of the occlusal plane in loop mechanics compared to sliding mechanics.

CONCLUSION

An oblique retraction force vector with a lower point of application causes less intrusion and more lingual tipping of upper anterior teeth as well as more clockwise rotation of the occlusal plane compared to a parallel retraction force vector.

Condylar positional changes and remodeling following bimaxillary anterior segment osteotomy with and without Le Fort I osteotomy: a three-dimensional comparative analysis

OBJECTIVE

To evaluate 3D condylar displacement and long-term remodeling following the correction of bimaxillary protrusion by anterior segment osteotomy (ASO) with and without Le Fort I surgery.

MATERIALS AND METHOD

This retrospective study included 32 adults with bimaxillary protrusion who underwent ASO alone (group 1) or with concomitant Le Fort I osteotomy (group 2). Subject's computed tomography scans at basic (T0), immediate postoperatively (T1), and at 1 year or more follow-up (T2) were collected. The condyle displacement was measured at superior-inferior, lateromedially, and anteroposterior surfaces, while condyle remodeling was measured at the superior, lateral, anterior, medial, and posterior surfaces. All 3D analyses were performed using 3D Slicer software (4.11.2).

RESULTS

At T1, 52.7%, 86.7%, and 94.4% of condyles in group 1 were displaced inferiorly, laterally, and posteriorly, respectively, as well as 75%, 89.2%, and 53.5% of condyles in group 2, which had not fully returned to the original preoperative positions at T2. Condylar remodeling was observed in both groups at T2, and no significant difference was found in the overall condylar volume between T1 and T2 in both groups. Patients in group 2 exhibited significant bone resorption at both lateral and anterior surfaces compared to group 1 (P = 0.000 and 0.01, respectively).

CONCLUSION

This study's results demonstrated that ASO is associated with a degree of condylar changes even if the posterior mandible is not osteomized. The positional changes vary between bimaxillary ASO alone and those with simultaneous Le Fort I osteotomy. However, both groups' condyle volume remained stable at the long-term follow-up.

Skeletal Anchorage Augmentation in Extraction/Nonextraction Orthodontic Treatment: A Randomized Clinical Study

AIM

To evaluate and compare skeletal, dental, and soft tissue parameters by therapeutic extraction of first premolar and nonextraction distalization of maxillary and mandibular arches in bimaxillary proclination using the skeletal anchorage system.

MATERIALS AND METHODS

About 40 orthodontic patients undergoing extraction or nonextraction treatment are enrolled in a randomized clinical trial. Participants are randomly assigned to either the extraction or nonextraction group and receive treatment augmented with skeletal anchorage. Mini implants were placed in the extraction group for retraction and infra-zygomatic crest (IZC) and buccal shelf screws were placed in the nonextraction group for distalization.

OBSERVATIONS AND RESULTS

Comparison between the ages of the patients among both Groups showed no significant difference. A significant difference is observed in dental and soft tissue parameters before and after the treatment in group A, whereas skeletal parameters also showed significant changes along with dental and soft tissue parameters in group B.

CONCLUSION

There is a significant change in the position of incisors by retraction and facial profile improves gradually in group A while for group B, a marked change in lower facial height was even seen. On comparing both the groups, a highly significant difference can be seen with respect to the amount of incisor retraction and change in molar inclination. The time taken for retraction of incisors is less in comparison to distalization.

CLINICAL SIGNIFICANCE

With this, we can easily avoid premolar extraction, and in cases of impacted third molars distalization as when indicated can be helpful as a part of the nonextraction treatment plan.

Changes in Soft Tissue Variable of Lips Following Retraction of Anterioir Teeth- A Cephalometric Study

Aim

The purpose of this study was to assess the short-term perioral soft tissue variations of the lips before and after treatment cases in 15 patients with bi-maxillary protrusion using treated lateral cephalograms who had already achieved active growth.

Methodology

Fifteen pre-treatment and post-treatment lateral cephalometric radiographs of 18-25-year-old individuals with bimaxillary protrusion treated with all four 1st premolar extractions were accessed from the records. From the reference planes and landmarks, 13 horizontal, 10 vertical, and 2 angular measurements were noted. Statistical comparisons between pre-treatment and post-treatment measurements were measured by a paired t-test to assess the importance of the mean variations at the predetermined significance level. Pearson's correlation coefficient (R) was utilized to assess the strength and significance of the linear relationship between the mean differences for paired (dependent and independent) variables.

Results

Pearson's correlation exhibited a noteworthy positive association between the horizontal changes in upper lip position and the horizontal changes of the upper incisor tip point (H-tU1) (R = 0.748), the upper incisor cervical point (H-cU1) (R = 0.707), the lower incisor tip point (H-tL1) (R = 0.839), and the lower incisor cervical point (H-cL1) (R = 0.767). This indicated that upper lip changes are the aftermath of the retraction of the upper and lower incisors in class I bi-maxillary protrusion malocclusion.

Conclusion

Thick upper lips showed more retraction of the upper lip in correlation with retraction of the incisors as compared with thin lips. The lower incisor cervical point displayed the strongest association with lower lip retraction.

Evaluation of the rate of anterior segment retraction in orthodontic patients with bimaxillary protrusion using friction vs frictionless mechanics

OBJECTIVES

To evaluate the effect of friction vs frictionless mechanics on the rate of anterior segment retraction (ASR) in patients with bimaxillary protrusion.

MATERIALS AND METHODS

Thirty females (18.3 ± 3.7 years) with bimaxillary protrusion were randomly allocated into the friction group, using elastomeric power chains, and the frictionless group, using T-loop springs for ASR. Eligibility criteria included absence of skeletal discrepancies and any systemic diseases or medications, among others. Randomization in a 1:1 ratio was generated by Microsoft Excel. Opaque sealed envelopes were sequentially numbered for allocation concealment. Only blinding of the outcome assessor was applicable. Activations were done every 4 weeks until completion of ASR. The primary outcome was the rate of ASR measured on digital models. Anchorage loss, molar rotation, and pain experienced were also assessed.

RESULTS

Two patients were lost to follow-up. The rate of ASR was 0.68 ± 0.18 mm/mo in the friction group vs 0.88 ± 0.27 mm/mo in the frictionless group, with no significant difference. A significant difference in anchorage loss of 1.63 mm and molar rotation of 7.06° was observed, being higher in the frictionless group. A comparable pain experience associated with both mechanics was reported.

CONCLUSIONS

No difference in the rate of ASR or pain experience was observed between friction and frictionless mechanics. However, extra anchorage measures should be considered when using frictionless mechanics as greater anchorage loss and molar rotations are anticipated.

Data on alveolar mandibular bone thickness in Class I skeletal patient with bimaxillary protrusion

The alveolar bone thickness influences both diagnosis and limitation of tooth movement, therefore significance retraction was commonly applied in treating patients with bimaxillary protrusion. This is a retrospective data collection of pre and post treatment lateral cephalographs from 18 to 40 years old patient treated with four premolars extraction. The alveolar mandibular bone thickness was identified in sagittal planes with Image-J software based on cephalometry lateral radiographs. Statistical analysis namely Wilcoxon test and Pearson correlation analysis coefficient were used to understand the correlation of alveolar mandibular bone thickness variables and mandibular incisors position to skeletal profile treated with first premolars extraction are presented. This data is essential for advancing in a further understanding of Class I skeletal patients with bimaxillary protrusion.

Severe skeletal bimaxillary protrusion treated with micro-implants and a self-made four-curvature torquing auxiliary: A case report

BACKGROUND

Bimaxillary protrusion is a clinically common dentofacial deformity, particularly among Chinese patients. This kind of malformation can severely affect facial esthetics and, even in mild cases, is difficult to correct without surgery. Unfortunately, many patients abandon treatment because of fear of surgery. Here, we describe a case of severe skeletal bimaxillary protrusion treated with nonsurgical orthodontic treatments, highlighting an alternative treatment option.

CASE SUMMARY

A 31-year-old woman wished to address a severe protrusion profile (approximately 8 mm overbite) and gummy smile. Cephalometric analysis and superimposition showed a severe skeletal class II pattern with a mandibular retrusion, and proclined and protrusive mandibular incisors. Panoramic radiograph showed a missing mandibular right third molar. A diagnosis of severe bimaxillary dentoalveolar protrusion was made. Taking into account the patient’s fear of orthognathic surgery, she accepted the proposed alternative treatment using micro-implants and a self-made four-curvature torquing auxiliary. The treatment allowed for maximal en masse anterior tooth retraction, proper relocation of incisors, and alleviation of the skeletal class II pattern. Esthetically, the patient’s lip protrusion was significantly decreased as was the overjet (from 10.5 mm to 1.8 mm), and the results remained stable throughout the 2-year follow-up.

CONCLUSION

Nonsurgical treatment using micro-implants and a four-curvature torquing auxiliary may benefit severe cases of skeletal bimaxillary protrusion in adults.

Displacement in root apex and changes in incisor inclination affect alveolar bone remodeling in adult bimaxillary protrusion patients: a retrospective study

BACKGROUND

Periodontal health is of great concern for periodontists and orthodontists in the inter-disciplinary management of patients with bimaxillary protrusion. The aim of present study is to investigate changes in the alveolar bone in the maxillary incisor region and to explore its relationship with displacement of root apex as well as changes in the inclination of maxillary incisors during incisor retraction.

METHODS

Samples in this retrospective study consisted of 38 patients with bimaxillary protrusion. Cone-beam computed tomography (CBCT) images was taken before(T0) and after (T1) treatment. Alveolar bone thickness (ABT), height (ABH) and area (ABA) were utilized to evaluate changes in the alveolar bone, while incisor inclination and apex displacement were used to assess changes in the position of maxillary central and lateral incisors. Correlations between alveolar bone remodeling and apex displacement as well as changes in the inclination were investigated.

RESULTS

The labial ABT of central and lateral incisors at the mid-root third was increased. In contrast, the palatal ABT at crestal, mid-root and apical third level were consistently decreased. ABH was not altered on the labial side, while significantly decreased on the palatal side. ABA was not significantly increased on the labial side, but significantly decreased on the palatal side, leading to a significantly reduced total ABA. Orthodontic treatment significantly reduced inclination of upper incisors. Changes in the amount (T1-T0) of ABA was remarkably correlated with apex displacement and changes of inclination (T1-T0); in addition, using the multivariate linear regression analysis, changes of ABA on the palatal side (T1-T0) can be described by following equation: Changes of palatal ABA (T1-T0) = - 3.258- 0.139× changes of inclination (T1-T0) + 2.533 × apex displacement (T1-T0).

CONCLUSIONS

Retraction of incisors in bimaxillary protrusion patients may compromise periodontal bone support on the palatal side. An equation that incorporated the displacement of root apex and change in the incisor inclination may enable periodontist-orthodontist interdisciplinary coordination in assessing treatment risks and developing an individualized treatment plan for adult patients with bimaxillary protrusion. Moreover, the equation in predicating area of alveolar bone may reduce the risks of placing the teeth out of the bone boundary during 3D digital setups.

Dental and soft tissue changes following extraction of second premolars in females with bimaxillary protrusion: A retrospective study

Background

Bimaxillary protrusion is a condition wherein esthetic concerns are the main reason behind seeking orthodontic treatment.

Aim

The aim of this retrospective cephalometric study was to evaluate the soft tissue profile and dental changes among female Saudi bimaxillary protrusion patients treated with extraction of all second premolars followed by retraction of the anterior teeth. Subjects and Methods: Pre and posttreatment cephalometric radiographs of adult female patients (ages 18-30 years) who underwent orthodontic therapy for Class I bimaxillary protrusion were obtained. Data were analyzed with SPSS^® software. A paired t-test and Pearson's correlation coefficients were conducted with the statistical significance set at 95% (P value < 0.05).

Results

At posttreatment, there was an overall decrease in the mean values among the majority of the soft tissue and dental cephalometric angles and linear measurements. Among soft tissue variables, there was a marginal increase in the upper lip length by 1.49 mm (P < 0.001), and the nasolabial angle increased markedly by 7.64° (P < 0.001). Similarly, a marked increase in retroclination by 5.95° (P < 0.001) was observed among the dental variables. Conversely, no significant changes were noted in the lower incisors. Pearson's correlation analysis revealed a significant correlation between all the different dental variables. Within the soft tissue variables, there was a significant positive correlation between changes in the upper lip protrusion, lower lip protrusion, upper lip thickness, and the distance from the upper and lower lips to the S-line.

Morphologic evaluation of root resorption after miniscrew assisted en mass retraction in adult bialveolar protrusion patients

Background

Bialveolar protrusion is one of the most common chief complaints from the Asian orthodontic patients. Typical orthodontic treatment includes extraction of the bimaxillary premolars and en mass retraction of anterior tooth with maximum anchorage by placing miniscrews. However, excessive pursuit of profile improvement by retraction and intrusion of anterior teeth may result in root resorption, alveolar bone loss, even dehiscence. Thus this retrospective, analytical study was to evaluate the root resorption of anterior teeth after miniscrew assisted en mass retraction in adult bialveolar protrusion patients.

Materials and methods

Thirty six adult patients with bimaxillary protrusion had four first premolars extracted, and then miniscrews were placed to provide anchorage. CBCT scans were performed before (T1) and posttreatment (T2). A new improvement project introduced for 3D CBCT registration assessment of root morphology. The paired t-test was used to compare changes from T1 to T2. The relationship between the root resorption and the movement of anterior teeth were assessed by Pearson correlation coefficient analysis.

Results

The significant differences were only found in apical third of root and the largest resorption in apical third of the root is always noted in the palatal and distal sectors. Significant correlations were observed in the loss of root in distal and palatal sectors, the root length and volume decrease with the amount of anterior teeth retraction and intrusion.

Conclusion

The new 3D registration assessment of root morphology will be helpful for the clinicians. Pursuit of large retraction and intrusion leads to obvious anterior teeth root resorption.

Management of an adult patient with missing one mandibular incisor, severe overjet, and midline discrepancy with asymmetric extraction, lingual appliance, and skeletal anchorage: A case report

This case report describes the lingual orthodontic treatment of an adult patient with Angle Class I malocclusion, agenesis of mandibular right central incisor, severe overjet and deep overbite, excessive proclination of maxillary and mandibular incisors, and midline discrepancy. Because of unique presentation, symmetric extraction could not be performed in the lower arch of this 34-year-old patient. She was treated with three premolar extractions and absolute anchorage with temporary anchorage devices for maximum retraction of upper anterior teeth. To correct the midline deviation and Bolton tooth-size discrepancy, the mandibular right lateral incisor, canine, and premolars were reshaped to reduce the mesiodistal width. The treatment approach greatly improved the patient's facial and dental appearance and provided a stable occlusion.

Orthodontic incisor retraction caused changes in the soft tissue chin area: a retrospective study

BACKGROUND

To investigate the area and morphological changes around the soft tissue chin after orthodontic incisor retraction.

METHODS

Fifty-nine female adults with bimaxillary protrusion requiring extraction of four premolars were included in the study. Cephalograms were taken before (T0) and after (T1) orthodontic treatment. The soft tissue changes, including the area, thickness and morphology were measured. Paired-t tests were performed for statistical comparisons. Pearson correlation analyses and backward multivariate regression analyses were used to identify the relationship between the soft tissue changes and incisor retraction.

RESULTS

Following the incisor retractions (5.35 ± 1.79 mm and 4.42 ± 1.62 mm for the upper and lower, respectively), there was a significant increase in the soft tissue thickness of L1c-LL (0.64 ± 1.67 mm, P = 0.025) and Pog-Pog' (0.44 ± 1.10 mm, P = 0.022), and a significant decrease in the soft tissue thickness of B-B' (1.21 ± 1.34 mm, P <  0.01). Changes in the area of soft tissue chin and lower lip were not statistically significant (P > 0.05). Pearson coefficient between the thickness changes of B-B' and the retraction of lower incisors was - 0.376. The multiple correlations between the soft tissue thickness changes and incisor retractions were Y = 1.02-0.42a + 0.42b for L1c-LL, and Y = 0.17-0.31b for B-B'.

CONCLUSIONS

The orthodontic incisor retraction could cause soft tissue thickness changes (i.e. an increase in L1c-LL and Pog-Pog' and a decrease in B-B') without area changes.

Evaluation of the airway space changes after extraction of four second premolars and orthodontic space closure in adult female patients with bimaxillary protrusion - A retrospective study

Background & objectives

Previous studies have found that first premolar extractions during orthodontic treatment may alter the upper airway dimensions. The objective of this study is to investigate the effects of second premolar extraction during orthodontic treatment on the dimensions of the upper airway in a sample of female adults.

Methods

Twenty-nine female adult patients with ages between 18 and 30 years old and incisor bimaxillary protrusion were included in this study. They were treated with comprehensive orthodontic treatment which included the extraction of four second premolars. Pre and post cephalometric radiographs were analyzed using Dolphin imaging software for changes in tongue length and height, soft palate thickness and length, the superior, middle, and inferior airway space, and vertical airway length. Descriptive statistics were used to characterize measurements. Student’s paired t-test was preformed to compare the pre- and post-test mean values of the dimensions.

Results

A significant increase in the vertical airway length was observed after the extraction of the second premolars (p = 0.02). The soft palate length showed a tendency towards an increase that did not reach statistical significance (p = 0.053). No other significant changes in the airway soft tissue measurements were observed. The proclination and protrusion of the upper and lower incisors were significantly decreased compared to pre-treatment measurements.

Interpretation & conclusions.

Orthodontic treatment involving the extraction of all four second premolars in females with bimaxillary protrusion increases the vertical airway length, which is the amount of distance between base of the tongue and posterior nasal spine. No other significant alterations in the upper airway measurements were observed.

Post-orthodontic cephalometric variations in bimaxillary protrusion cases managed by premolar extraction - A retrospective study

Background

Bimaxillary protrusion is a common dentofacial condition associated with proclination of maxillary and mandibular incisors in relation to the dental and cranial bases resulting in soft tissue procumbency. The present retrospective study aimed to investigate dental and soft tissue profile changes using cephalometric analysis to evaluate bimaxillary protrusion patients after extraction of the first four premolars and subsequent retraction of the anterior teeth.

Materials and Methods

Pre-treatment and post-treatment cephalometric radiographs of 46 Saudi patients (16 males and 30 females), 18-30 years of age with bimaxillary protrusion, were selected based on inclusion criteria. Dental and soft tissue landmarks were traced using the Dolphin® imaging software and statistically analyzed with SPSS® 21 software.

Results

The upper and lower incisors retroclined by a mean value of 9.6° and 9.65°, respectively, and an average distance of 4.1 mm. The level of maxillary incisor exposure was reduced by approximately 1.1 mm after treatment. A mean increase of 6.6° in the nasolabial angle was also observed. Multiple regression analysis showed that retraction of both upper and lower incisors by 1 mm would result in a 0.44 mm retraction of the upper and lower lips.

Conclusion

A statistically significant increase in the nasolabial angle and upper lip length was found in relation to upper and lower incisor retraction and retroclination. A significant reduction was also evident in the post treatment upper incisor exposure, facial convexity angle and mentolabial sulcus depth.

Evaluation of levels of Interleukin-1b, intensity of pain and tooth movement during canine retraction using different magnitudes of continuous orthodontic force

Aim:

The present study was conducted for the evaluation of Interleukin (IL)-1b levels in human gingival crevicular fluid (GCF), intensity of pain, and the amount of tooth movement measured during canine retraction using different magnitudes of continuous orthodontic force.

Materials and Method:

A statistically significant number of subjects were included for the study (n = 16, 6 male subjects and 10 female subjects). The age ranged from 18 to 24 years and all were diagnosed with Class I bimaxillary protrusion. They underwent first premolar extractions prior to participating in the study. The maxillary cuspids were then retracted using a continuous force of either 50 or 150 g. This was executed using nickel–titanium coil springs on segmented archwires. The opposite counterpart, that is, mandibular cuspid was used as control. GCF was then drawn from the distal aspect of each tooth at defined time intervals. This was followed by the assessment of IL-1b concentrations, pain intensity, using the visual analogue scale (VAS), and the amount of tooth movement. ANOVA test, Friedman test, and paired t-tests were used for comparisons of IL-1b in GCF, the plaque and gingival indices, and the efficiency of tooth movement on pain perception, respectively.

Results:

The 150 g group showed the highest level of IL-1b concentration at 24 h from baseline and at 2 with significant differences compared with the control group (P < 0.05). The mean VAS score of pain intensity from the 150 g force was significantly greater than from the 50 g force at 24 h (P < 0.01).

Conclusion:

No significant difference in the amount of tooth movement was found between these two different magnitudes of continuous force at 2 months. A 50 g force could effectively induce tooth movement similar to 150 g with less pain and less inflammation.

Soft Tissue Changes Following Combined Anterior Segmental Bimaxillary Orthognathic Procedures

AIMS & OBJECTIVES

To analyze the soft tissue response in patients treated by combined anterior segmental bimaxillary procedures.

METHODS

A  Prospective, observational and analytical study was carried out for a period of 2 years involving 37 patients with predefined inclusion and exclusion criteria; lateral cephalograms were taken by the same operator on the standardized unit immediately before and 6 months after surgery; hard and soft tissue landmarks were measured in millimeters to both horizontal and vertical reference lines; any differences in distances were recorded as a surgical change; appropriate statistical test was carried; level of significance was p < 0.05.

RESULTS

All patients underwent anterior maxillary osteotomy with 34 anterior mandibular osteotomies, 2 advancement genioplasties and 1 reduction genioplasty. Analysis showed significant angular, horizontal and vertical change. The significant differences in skeletal variables were observed in N-Pg distance, overjet, overbite, U1-NF angle, L1-Mp angle and soft tissue variables like labiomental angle, upper-lower lip protrusion, upper-lower lip length and lower incisor to labrale inferius distance. Nasolabial angle, interlabial gap and upper incisor exposure were extremely significant.

CONCLUSION

Soft tissue response to surgery is perhaps more predictable after 6 months, so this may be a treatment modality of choice in adult bimaxillary/dentoalveolar protrusion patients who need instant esthetic facial results.

Effects of force magnitude on torque control in the correction of bimaxillary protrusion with mass retraction

OBJECTIVES:

This study was designed to explore whether force magnitude would influence incisor torque control and the overall outcome in patients with bimaxillary protrusion who need mass incisor retraction.

MATERIALS AND METHODS:

Forty-one female patients (aged > 15 years) with bimaxillary protrusion requiring mass incisor retraction were selected. Two sliding mechanics were utilized, with the elastic group receiving a light force of ~100 g by wearing elastics and the power chain group receiving a moderate force of ~250 g by power chain. Lateral cephalograms obtained before and after treatment were traced and measured.

RESULTS:

Patients in both groups displayed maxillary protrusion with a similar skeletal class II tendency. A longer treatment time was found in the elastic group. No difference in the distance of incisor tip movement was observed between the two groups; however, a larger inclination of upper incisors was found in the elastic group, indicating less loss of torque. In addition, larger reduction in Sella-Nasion-A and A-Nasion-B angle was observed in the elastic group, which was accompanied by a larger ratio of upper lip retraction to upper incisor retraction as well as more upper lip retraction.

CONCLUSIONS:

Sliding mechanics with elastics to generate light forces can achieve better torque control with more reduction in skeletal and soft tissue protrusion.

Cone-beam computed tomography-based diagnosis and treatment simulation for a patient with a protrusive profile and a gummy smile

For patients with bimaxillary protrusion, significant retraction and intrusion of the anterior teeth are sometimes essential to improve the facial profile. However, severe root resorption of the maxillary incisors occasionally occurs after treatment because of various factors. For instance, it has been reported that approximation or invasion of the incisive canal by the anterior tooth roots during retraction may cause apical root damage. Thus, determination of the position of the maxillary incisors is key for orthodontic diagnosis and treatment planning in such cases. Cone-beam computed tomography (CBCT) may be useful for simulating the post-treatment position of the maxillary incisors and surrounding structures in order to ensure safe teeth movement. Here, we present a case of Class II malocclusion with bimaxillary protrusion, wherein apical root damage due to treatment was minimized by pretreatment evaluation of the anatomical structures and simulation of the maxillary central incisor movement using CBCT. Considerable retraction and intrusion of the maxillary incisors, which resulted in a significant improvement in the facial profile and smile, were achieved without severe root resorption. Our findings suggest that CBCT-based diagnosis and treatment simulation may facilitate safe and dynamic orthodontic tooth movement, particularly in patients requiring maximum anterior tooth retraction.

Effect of retraction of anterior teeth on pharyngeal airway and hyoid bone position in Class I bimaxillary dentoalveolar protrusion

BACKGROUND

To test the hypothesis that the retraction of anterior teeth has no effect on the dimensions of pharyngeal airway and to evaluate the retraction of anterior teeth on each parameter of pharyngeal airway.

METHODS

Twenty-two adult patients of Class I bimaxillary protrusion requiring first premolar extractions with maximum anchorage requirements were selected. The pharyngeal airway and dentofacial parameters of the patients were compared using pre- and post-treatment lateral cephalograms with the help of Student's paired t-test (P < 0.05). The relationship between airway size and dentofacial parameters was also evaluated using Pearson correlation coefficient.

RESULTS

The upper and lower lips were retracted by 2.25 and 5.4 mm after retraction of the incisors. The tips of upper and lower incisors were retracted by 7.75 and 7.15 mm, respectively. There was a statistically significant decrease in SPP-SPPW (P < 0.05), U-MPW (P < 0.001), TB-TPPW (P < 0.001), and change in HRGN (P < 0.01). A significant correlation was observed between the amount of retraction of lower incisor and decrease in the pharyngeal airway posterior to soft palate (r = 0.102), tongue (r = 0.322), and change in HRGN (r = 0.265).

CONCLUSIONS

The size of the pharyngeal (velopharyngeal and glossopharyngeal) airway reduced and hyoid bone position changed after retraction of the incisors in extraction space in bimaxillary protrusive adult patients.

The Facial Aesthetic index: An additional tool for assessing treatment need

Objectives:

Facial Aesthetics, a major consideration in orthodontic diagnosis and treatment planning, may not be judged correctly and completely by simply analyzing dental occlusion or osseous structures. Despite this importance, there is no index to guarantee availability of treatment or prioritize patients based on their soft tissue treatment needs. Individuals having well-aligned teeth but unaesthetic convex profiles do not get included for treatment as per current malocclusion indices. The aim of this investigation is to develop an aesthetic index based on facial profiles which could be used as an additional tool with malocclusion indices.

Materials and Methods:

A chart showing typical facial profile changes due to underlying malocclusions was generated by soft tissue manipulations of standardized profile photographs of a well-balanced male and female face. A panel of 62 orthodontists judged the profile photographs of 100 patients with different soft tissue patterns for assessing profile variations and treatment need. The index was later tested in a cross-section of school population. Statistical analysis was done using “irr” package of R environment version 2.15.1.

Results:

The index exhibited very good reliability in determining profile variations (Fleiss kappa 0.866, P < 0.001), excellent reproducibility (kappa 0.9078), high sensitivity, and specificity (95.7%). Testing in population yielded excellent agreement among orthodontists (kappa 0.9286).

Conclusions:

A new Facial Aesthetic index, based on patient's soft tissue profile requirements is proposed, which can complement existing indices to ensure treatment to those in need.

Comparative evaluation of anchorage reinforcement between orthodontic implants and conventional anchorage in orthodontic management of bimaxillary dentoalveolar protrusion

BACKGROUND

Increased upper lip procumbency is commonly associated with maxillary dentoalveolar protrusion with the major goal of reducing maxillary dentoalveolar protrusion. The treatment plan usually includes extraction of the maxillary first premolars, followed by retraction of anterior teeth with maximum anchorage. Dental implants have been widely accepted as successful adjuncts for obtaining maximum anchorage in orthodontic treatment.

METHODS

50 subjects between the ages of 13 and 17 years having bimaxillary dentoalveolar protrusion were included in the study. The patients were divided into two groups. Both groups received treatment with 0.022″ MBT prescription preadjusted edgewise appliance system. In addition, subjects of Group 'I' received the Nance button and lingual arch as anchorage reinforcement in the upper and lower arches, respectively. Subjects of Group 'II' received self-drilling titanium OI for anchorage reinforcement.

RESULTS

Significant retraction was achieved in all cases with good vertical control. Anchor loss was observed in both groups. Anchor loss was much higher in Group I compared to Group II, and an intergroup comparison for anchor loss was highly significant.

CONCLUSION

Implants as anchorage, for en masse retraction, can be incorporated into orthodontic practice. The use of orthodontic implants for anchorage is a viable alternative to conventional molar anchorage.

Space closure with loop mechanics for treatment of bimaxillary protrusion: a case report

This case report intends to highlight the space closure with tear drop loop mechanics for bimaxillary protrusion. Loops can be fabricated in a sectional or full arch wire, and closing loops are usually used in loop mechanics for extraction space closure. The major advantage of loop mechanics is the lack of friction between the bracket and arch wire during space closure. An adult patient with bimaxillary protrusion reported to the clinic. The patient was treated successfully by maximum retraction of maxillary and mandibular anterior teeth after extraction of all first premolars. Space closure was begun using a moment differential between posterior and anterior segments created by a Tear drop loop. Anterior teeth were moved with bodily movement, and no anchorage loss of the posterior segments was seen using a Tear drop loop spring. A stable result with normal over jet and overbite was achieved with retraction of maxillary and mandibular anterior teeth. With a Tear drop loop, individual biomechanical responses can be achieved, and it is possible to calculate force magnitude for every patient.

Correlation between objective and subjective evaluation of profile in bimaxillary protrusion patients after orthodontic treatment

OBJECTIVE

To correlate the objective cephalometric measurements with subjective facial esthetics in patients with bimaxillary protrusion.

MATERIALS AND METHODS

The sample consisted of 60 Asian-Chinese patients with bimaxillary protrusion who met the inclusion criteria. The facial esthetics of posttreatment profile and the change of profile on standardized lateral photographs were rated by a panel of 10 orthodontists and a panel of 10 lay persons with bimaxillary protrusion. All of the pretreatment and posttreatment cephalograms were digitized and traced. Twenty-five cephalometric measurements were constructed and analyzed. Correlations between the subjective facial esthetic scores and each cephalometric measurement were evaluated.

RESULTS

The cephalometric measurements correlated with the facial esthetic scores of posttreatment profile given by the orthodontist and the lay persons were basically the same. For the evaluation of posttreatment profile in bimaxillary protrusion patients, the upper and lower lip to E-line, upper and lower incisor tip to AP plane, Pg-NB distance, mentolabial angle, and sulcus depth correlated significantly with the esthetic score. For the evaluation of profile change during orthodontic treatment, retraction of upper incisor relative to AP plane or the perpendicular line through sella (line Y), change of upper incisor inclination, change of mentolabial sulcus depth, and retraction of lips relative to E-line were correlated positively with the esthetic value.

CONCLUSIONS

Cephalometric measurements of lip position, incisor position, and chin morphology were key parameters correlated to facial esthetics.

The role of alveolar corticotomies in orthodontic anchorage management

The aim of this article is to describe our therapeutic approach in the management of Class III malocclusions requiring repositioning of the anterior-inferior segment. This approach is based on the reasoned use of selective alveolar corticotomies in anchorage management. The patient was a 17-year-old young woman presenting severe antero-inferior crowding, a Class III malocclusion and residual spaces in the upper arch. Orthodontic treatment consisted of extraction of the mandibular 1st premolars and maximum anchorage. A local mandibular corticotomy was performed prior to orthodontic treatment from the distal aspect of the right canine to the distal surface of the left canine, sparing the premolar segments. The maxillary arch received no corticotomy and was treated by conventional orthodontic techniques. En masse retraction of the 6 antero-inferior teeth was done using sliding mechanics. Active treatment was completed in 8 months. The corrections are still stable 2 years post-retention.

PAOO technique for the bimaxillary protrusion: Perio-ortho interrelationship

An increasing number of adult patients have been seeking orthodontic treatment, and a short treatment time has been a recurring request. To meet their expectations, a number of innovative techniques have been developed to accelerate orthodontic tooth movement. Significant acceleration in orthodontic tooth movement has been extensively reported following a combination of selective alveolar decortication and bone grafting surgery with the latter being responsible for the increased scope of tooth movement and the long-term improvement of the periodontium. Six patients who have been diagnosed as class I malocclusion with bimaxillary protrusion were selected. A modified corticotomy procedure was carried out The active orthodontic treatment was begun within 1 week after surgery and follow up. All the patients reported the minmalpain and mild swelling 2 days following the surgical procedure. The mean treatment time for these patients was 17.4 months, with the distalization of the canines being mostly completed in 8.5 months. Periodontallyaccelerated osteogenicsorthodontic tooth movement procedure or selective alveolar decortications or corticotomy approach is one of the surgical techniques developed to reduce the time for orthodontic treatment. This newer approach is leading to short orthodontic treatment time and great patient acceptance.

Bimaxillary protrusion: an overview of the surgical-orthodontic treatment

Bimaxillary protrusion is a commonly seen deformity in Asian populations. This condition is characterized by protrusive and proclined upper and lower incisors and an increased procumbency of the lips. It is usually combined with lip incompetence, gummy smile, mentalis strain, and anterior open bite. Facial aesthetics is the primary concern of these patients. Successful treatment depends on a thorough evaluation and understanding of this dentofacial deformity. Typical orthodontic treatment includes retraction and retroclination of maxillary and mandibular incisors after extraction of the four first premolars. Orthognathic surgery is required to correct significant skeletal problems. Anterior subapical osteotomies and extraction of premolars can correct sagittal excess of the jaw bones and relieve dental crowding. Segmental maxillary osteotomies are performed to treat patients with an associated exaggerated curve of Spee and vertical maxillary excess. Differential intrusion of anterior and posterior maxilla/maxillary segments with clockwise rotation of the occlusal plane is a useful technique for treatment of anterior open bite and creation of a consonant smile arc. Le Fort I osteotomy with setback sometimes provides an alternative to segmental maxillary osteotomies. Meticulous planning and execution of osteotomies in accordance with surgical planning are essential for aesthetic and functional outcome.