Maxillary Impaction Surgery Research Articles

Comparison of smile attractiveness in cases with gummy smile treated with botulinum toxin and maxillary impaction surgery: A retrospective study

This study aimed to compare the smile's attractiveness in patients submitted to the treatment of gummy smiles with botulinum toxin or maxillary impaction surgery. The retrospective sample comprised 26 patients divided into two groups: Group 1 (BTX): 13 patients (12 females and 1 male) with a mean age of 28.06 years (s.d. = 6.09) and mean gingival exposure during smile of 5.18 mm (s.d. = 1.51) treated with botulinum toxin; Group 2 (SURGICAL): 13 patients (9 females and 4 males) with a mean age of 30.59 years (s.d. = 5.72) and mean gingival exposure during smile of 5.21 mm (s.d. = 1.55) treated with orthognathic maxillary impaction surgery. The group of evaluators comprised 317 participants, divided into 143 orthodontists (85 females and 58 males) with a mean age of 41.40 (s.d. = 9.30); 62 dentists (47 female and 15 male) with a mean age of 35.44 (s.d. = 10.44), and 112 lay people (74 female and 38 male) with a mean age of 46, 91 (s.d. = 10.11) in a questionnaire on Google Forms. Without knowing the therapy used, the evaluators assigned scores to the photographs of the posed smile taken before (T1) and after (T2) treatment. Intergroup comparison of smile attractiveness was performed using the t-independent, one-way ANOVA, and Tukey tests.There was a significant improvement in smile attractiveness with treatment in both groups; however, the improvement was significantly better in the surgical group than in the BTX group. Orthodontists rated smile attractiveness significantly higher than dentists and laypersons for the final phase of the BTX and surgical groups.There was a significant improvement in the smile attractiveness with botulinum toxin application and orthodontic-surgical treatment. However, orthognathic surgery promoted a greater improvement in smile attractiveness than the application of botulinum toxin.

What Is the Effect of Maxillary Impaction Orthognathic Surgery on Voice Characteristics? A Quasi-Experimental Study.

Regarding the impact of orthognathic surgery on the airway and voice, this study was carried out to investigate the effects of maxillary impaction surgery on patients' voices through acoustic analysis and articulation assessment. This quasi-experimental, before-and-after, double-blind study aimed at examining the effects of maxillary impaction surgery on the voice of orthognathic surgery patients. Before the surgery, a speech therapist conducted acoustic analysis, which included fundament frequency (F0), Jitter, Shimmer, and the harmonic-to-noise ratio (HNR), as well as first, second, and third formants (F1, F2, and F3). The patient's age, sex, degree of maxillary deformity, and impaction were documented in a checklist. Voice analysis was repeated during follow-up appointments at one and six months after the surgery in a blinded manner. The data were statistically analyzed using SPSS 23, and the significance level was set at 0.05. Twenty two patients (18 females, 4 males) were examined, with ages ranging from 18 to 40 years and an average age of 25.54 years. F2, F3, HNR, and Shimmer demonstrated a significant increase over the investigation period compared to the initial phase of the study (P <0.001 for each). Conversely, the Jitter variable exhibited a significant decrease during the follow-up assessments in comparison to the initial phase of the study (P< 0.001). Following maxillary impaction surgery, improvements in voice quality were observed compared to the preoperative condition. However, further studies with larger samples are needed to confirm the relevancy.

Effect of maxillary impaction on mandibular surgical accuracy in virtually-planned orthognathic surgery: A retrospective study

Although surgical accuracy has been evaluated in bi-maxillary procedures, few studies have investigated the relationship between maxillary and mandibular accuracy. The present study evaluated the effect of maxillary impaction accuracy on mandibular surgical outcome.This cohort study analyzed skeletal class III patients who underwent planned maxillary impaction in bi-maxillary surgery. The primary predictor was the difference between the virtual plan and surgical outcome in the maxilla, as determined by three-dimensional (3D) and vertical differences. The secondary predictors were the planned 3D distances in the maxilla and mandible. The primary outcome was mandibular surgical accuracy, defined as the difference between the planned and actual outcomes, calculated as 3D Euclidean distance.The study included 73 patients. Increased differences between the planned and actual outcomes in the maxilla were associated with increased differences in the mandible. The post-operative position of the mandible was closer to the planned position when the position of the impacted maxilla was superior than when it was inferior to the planned position.Moving the maxilla closer to the planned position resulted in a more accurate mandibular position. These findings suggest that careful surgical procedures are needed to avoid inferior positioning of the maxilla during maxillary impaction surgery.

Short-Term Stability After Segmental Le Fort I Maxillary Impaction Surgery With Mandibular Autorotation in Seven High-Angle Class II Patients: A Case Series.

To retrospectively evaluate skeletal stability after Le Fort I maxillary impaction surgery and mandibular autorotation without bilateral sagittal split osteotomy (BSSO) in high-angle class II patients. Seven female high-angle class II patients who underwent maxillary impaction surgery and mandibular autorotation without bilateral sagittal split osteotomy were included in this study. Surgical changes and relapse were measured on lateral cephalograms taken preoperatively and at 1 month, 6 months and 1 year postoperatively. The horizontal movement of the maxilla at point A was 5.8 ± 3.3 mm backward, and the upward movement at the posterior nasal spine was 3.3 ± 1.4 mm. The mean horizontal change at point A during the 1-year follow-up period was 0.1 ± 0.2 mm, and the vertical change at posterior nasal spine was 0.2 ± 1.3 mm, which were not statistically significant. The horizontal surgical change at point B was 4.0 ± 1.8 mm forward and the vertical surgical change at point B was 4.7 ± 1.8 mm upward. Postoperative relapse was 10.9% and 13.7% in the horizontal and vertical directions, respectively. Le Fort I maxillary impaction surgery with mandibular autorotation may be 1 of the suitable procedures for high-angle class II patients.

Temporomandibular joint stability after two types of maxillary impaction surgery in patients with skeletal class II open bite due to condylar deformations: a preliminary study

ABSTRACT Purpose: The aim of this study was to evaluate the effect of two types of mandibular autorotation concept (MAC) surgery using maxillary impaction combined with a straight locking miniplate (SLM) technique on the condyles of patients with skeletal Class II open bite. Materials and methods: Fourteen female patients with skeletal Class II mandibular retrusion with open bite were included in this study. The patients were divided into two groups based on the type of MAC surgery performed: a group of subjects who underwent maxillary impaction only (MAC-1 group) and a group of subjects who underwent maxillary impaction combined with mandibular osteotomy (MAC-2 group). A 3D-printing CAD/CAM wafer was fabricated. The SLM technique was performed to stabilize the vertical maxillomandibular relationship during surgery. A computed tomographic image was obtained preoperatively as well as on the third post-surgical day and 1 year post-surgically to evaluate the relapse by assessing changes in cephalometric measurements, condylar volume, and condylar surface area. Results: Neither the MAC-1 group nor the MAC-2 group showed significant changes in their condylar surface area that could have led to skeletal relapse. The condylar volume was significantly decreased in the MAC-2 group, but the affected location did not contribute to the relapse of the mandibular position. Conclusion: Our findings suggest that MAC surgery with the SLM technique in patients with skeletal Class II retrognathia did not result in post-surgical relapse or further deformation and resorption of the condyle; rather, it yielded promising functional and morphological stability.

Cephalometric Evaluation of Maxillary and Mandibular Centers of Rotation Subsequent to Maxillary and Mandibular Surgery

Background: Due to significant effect of joint orthodontic and surgical treatment planning on the patients’ facial appearances, precise prediction of surgical outcomes is of great importance. Objectives: The aim of this study was to determine the maxillary and mandibular centers of rotation and its distance to center of condyle (CC) in patients who underwent maxillary impaction surgery concomitant with mandibular advancement or setback surgery and also to determine the correlation between maxillary center of rotation (MxCR) with that of mandible (MnCR) and also the direction of rotation in distal and proximal segments of the mandible. Methods: Preoperative and postoperative lateral cephalograms of 24 adult non-syndromic patients were studied. Using cephalometric tracings MxCR was located as the intersection of ANS-PNS (preoperative) and ANS’-PNS’ (postoperative) lines. MnCR was located using Reuleaux method, where perpendicular bisectors of B-B’ and Go-Go’ lines meet. Using statistical analysis of correlation and comparison, all the points’ coordinates and centers of rotation were compared. Results: The average distance of MnCR to CC was 10.45 cm and the average distance of MxCR to CC was 8.39 cm. MxCR and MnCR had positive correlation in horizontal plane and they had negative correlation in vertical plane but the correlation was insignificant (P &gt; 0.05). In addition, there seemed to be no specific pattern in the direction of mandibular proximal and distal segments’ rotations. Conclusions: The results showed that: (1) The center of rotation calculated for mandible after bimaxillary surgery was not located within the condylar area. But generally whenever MxCR was closer to ANS, MnCR was located more anteriorly. (2) In patients with decreased distance between MxCR and SN line, MnCR would be located more superiorly. Also, whenever MxCR had greater distance from condyle, the MnCR to condyle distance was greater too. (3) The direction of rotation in proximal and distal segments of mandible had no specific pattern.

Postoperative stability of conventional bimaxillary surgery compared with maxillary impaction surgery with mandibular autorotation for patients with skeletal class II retrognathia.

We aimed to compare the postoperative stability of conventional bimaxillary surgery (with bilateral sagittal split osteotomy) with that of maxillary impaction surgery (with mandibular autorotation without bilateral sagittal split osteotomy) in patients with skeletal class II retrognathia. Patients were assigned to have conventional bimaxillary surgery (conventional group, n=6) or mandibular autorotation (experimental group, n=7). Measurements were made using serial lateral cephalometric radiographs taken immediately preoperatively (T0), immediately postoperatively (T1), and one year later (T2) to assess the variation in operative change (T1-T0) and relapse (T2-T1). There was no significant difference in median (range) surgical change in the anterior movement at point B (conventional group, 4.5 (3.0-11.0) mm; experimental group 4.1 (2.1-6.4) mm). However, there was a significant difference in median (range) surgical posterior movement relapse at point B (conventional group -1.7 (-2.3 to -0.5) mm; experimental group -0.6 (-1.0 to 1.0) mm; p=0.032). Mandibular advancement with mandibular autorotation is therefore a more stable procedure than mandibular advancement with bilateral sagittal split osteotomy in patients with skeletal class II retrognathia.

Evaluation of Three-Dimensional Changes in Pharyngeal Airway Following Isolated Lefort One Osteotomy for the Correction of Vertical Maxillary Excess: A Prospective Study.

Orthognathic surgery involves movement of jaws in all three planes, and this being a part of airway complex, displacement of jaws can influence the dimension of airway at all levels. Lefort one osteotomy surgery with superior repositioning is a common procedure done for patients with vertical maxillary excess. The purpose of this study was to evaluate the three-dimensional volumetric changes in airway after lefort one impaction surgery using three-dimensional cone beam computed tomography (3D-CBCT) in patients with vertical maxillary excess (VME). A prospective analysis of 15 patients who underwent isolated lefort one impaction surgery was done with pre-operative (T0) and 3-months (T1) post-operative 3D-CBCT scans. Airway was divided into three segments, nasopharyngeal, velopharyngeal and oropharyngeal. Volumetric analysis of all these segments was done before and after surgery. Paired 't test' was used to assess the mean difference in airway volume and area between T0 and T1. One-way ANOVA was used to check the mean percentage difference in airway volume and area among the three segments. The mean percentage of nasopharyngeal volume difference was - 0.6299 ± 0.9146%, velopharyngeal volume difference was - 0.5205 ± 1.107%, oropharyngeal volume difference was - 1.492 ± 2.745%. Though volume and area of pharyngeal airway were decreased after maxillary impaction surgery in all three segments of airway studied, they were not statistically significant. Among the three segments of airway studied, oropharyngeal airway volume has shown the highest post-surgical reduction though statistically insignificant. ESS scores were within normal limits. Hence, we are of the opinion that there is lack of evidence to conclude that the patients undergoing lefort one superior repositioning for the treatment of VME might develop significant narrowing of PAS that may predispose the patient to breathing disorders.

Changes in the nasolabial angle associated with advance and maxillary impact surgery

Objectives: The aim of this study is to determine changes that occur in the nasolabial angle (ANL) in patients who received Le Fort I advancement surgeries with or without maxillary impaction. Methods: A cephalometric evaluation of McNamara was performed in 16 healthy Chilean patients after orthognathic surgeries. Only patients with pre- and postsurgery teleradiography were included in this study. The radiographs were standardised in head posture position, with olives and first tooth contact. Pre- and postsurgery images were on the same scale (1:1). A comparison was made between two types of surgeries: (1) forehead and maxillary impaction (eight patients); (2) pure maxillary advancement (eight patients). The efficiency of the ANL change in degrees was demonstrated. Cephalometric analysis was measured with Nemoceph 11 software, by a calibrated operator, between 2 and 4 weeks after surgery. Findings: Maxillary movement showed that maxillary impaction and maxillary impaction surgery produced an average increase of 15.125°, while pure advancement determined an average increase of 8.625°. Thus, it was established that the maxillary impaction and advancement surgery is more efficient in the change of nasolabial angulation. Conclusion: The objective of this study was to determine the most efficient maxillary movement to achieve changes in ANL. This is of paramount importance in surgical planning, because when considering these results, the clinician will be able to predict what kind of movement is convenient and how much the patient's soft profile may change after one or the other type of maxillary movement.

Long-term skeletal and profile stability after surgical-orthodontic treatment of Class II and Class III malocclusion

ObjectiveThe purpose of this perspective research was to study the long-term stability of skeletal, dentoalveolar and soft tissue after orthognathic surgery in subjects presenting with Class II and Class III malocclusions. MethodsThe available digitized cephalometric radiographs, including pretreatment (t0), presurgery (t1), a minimum of 12 months postsurgery (t2) and at least 3 years after the orthosurgery treatment (t3) were taken between 1998 and 2010. In Group 1 mandibular advancement and in Group 2 mandibular advancement and maxillary impaction surgery were performed for correction of Class II. In Group 3 maxillary advancement and in Group 4 surgical maxillary advancement with mandibular setback, for correction of Class III. ResultsIn all the phases mandibular length was shorter in Group 1, and the inferior third of the face was longer in Group 2. Before the surgery there was greater maxillary deficiency in Group 3 than Group 4 and mandibular length was longer in Group 4. ConclusionIn Groups 1 and 2, at retention phase, relapse occurred due to the increase in mandibular plane, whereas the surgeries performed in Groups 3 and 4 remained stable.

Residents’ journal review

Residents’ journal review

Changes of Hyoid, Tongue and Pharyngeal Airway after Mandibular Setback Surgery by Intraoral Vertical Ramus Osteotomy

To assess changes in hyoid, tongue, pharyngeal airway, and head posture in patients who had mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) and to investigate the influence of LeFort I osteotomy. Sixty patients with skeletal Class III malocclusion were evaluated. All patients had mandibular setback surgery via IVRO, and 45 patients had additional maxillary impaction surgery via LeFort I osteotomy. Lateral cephalograms were taken before, immediately after, approximately 1 month after, and at least 1 year after surgery. Parameters indicating the hyoid, tongue, pharyngeal airway, and head posture were evaluated. The hyoid significantly moved inferoposteriorly immediately after surgery and relapsed superoanteriorly during observation periods. The tongue significantly moved posteriorly during all periods. The final position of the hyoid and tongue was significantly posterior, and the final pharyngeal airway was significantly narrower compared with its presurgical position. Significant cervical hyperflection occurred during observation periods and was strongly correlated with anterior movement of the hyoid. The hyoid and tongue showed similar positions regardless of the presence of different genders or LeFort I osteotomy after the long-term observation period. The hyoid and tongue moved posteriorly after mandibular setback surgery via IVRO, and there was a tendency to relapse back to its original position. However, the final pharyngeal airway width remained narrower after the long-term observation period. Based on our results, careful monitoring of the airway may be needed after mandibular setback surgery via IVRO.

The Relation Between Pogonion Advancement and Posterior Maxillary Impaction

Controversy exists about the relation between the amount of posterior maxillary impaction and pogonion (P) advancement. The aims of the current study were to (1) propose a formula to predict the amount of P advancement due to posterior maxillary impaction surgery, (2) predict the amount of posterior maxillary impaction by means of a formula to achieve the best facial harmony, and (3) identify the compatibility between proposed formulas and the actual resultant mandibular position after posterior maxillary impaction surgery. For obtaining the formulas, 2 cephalograms were taken from 1 patient in centric occlusion and rest position. Afterward, mandibular rotational center was obtained by superimposing the cephalograms; by the help of which the 2 formulas were obtained. To check the reliability of the formulas, 10 patients with the mean age of 21 +/- 1.5 years who had undergone posterior maxillary impaction were selected. The presurgical and postsurgical cephalograms of patients were obtained. These cephalograms were superimposed to find the center of mandibular rotation. Pearson correlation coefficient test was used to evaluate the relation between the suggested formulas and the clinical data. This test showed that there were significant correlations between maxillary impaction and P advancement in both the formulas and clinical evaluation. This correlation (r) was 0.993 (P < 0.001) based on formulas and r = 0.806 (P < 0.005) based on tracing. This study showed that the amounts of anterior facial height reduction and P advancement were almost the same, and the anterior facial height was reduced 1.5 times more than the amount of maxillary impaction.

Prediction of mandibular autorotation

Purpose: The purpose of this investigation was to test the hypothesis that the mandible rotates around the same point during maxillary impaction surgery as during initial jaw opening. This point, called the center of mandibular autorotation (CAR), could then be used to predict mandibular position and to decide whether only maxillary impaction would be needed to correct the occlusion and the facial profile. Patients and Methods: Preoperatively, two lateral cephalograms were obtained from a consecutive series of 20 patients who underwent maxillary impaction without concomitant mandibular ramus osteotomy. One cephalogram was taken with the mandible in centric relation using a wax bite wafer and another with a jaw opening of 10 mm using a fabricated acrylic bite block with the mandible manipulated to its most retruded position. The CAR was calculated before and after jaw opening using the Rouleaux method on the lower incisor and gonion point. A third lateral cephalogram was taken within 2 days postoperatively. The postoperative lower incisai point was then transferred to the first cephalogram using cranial base superimposition. Results: When the preoperative and postoperative distances between CAR and incisai point were compared, there was no significant difference between these distances, proving the hypothesis. Conclusions: The method used is a practical and precise way to determine the center of mandibular autorotation on an individual basis. The center of rotation during initial jaw opening is the same as during impaction surgery.

A practical and precise technique to predict the position of the autorotated mandible in maxillary impaction surgery

In the simplified Couinaud classification, in which the liver is divided into eight segments, each supplied by a central vasculo-biliary sheath, little attention is given to the high prevalence of anatomical variations which occur, especially in the right hemiliver. Using volumetric acquisition techniques, such as magnetic resonance imaging or spiral computed tomography scanning, detailed insight into the individual segmental anatomy can now be obtained in a non-invasive manner. The significance of this anatomical insight lies in the planning of anatomical resections, whereby the relationship between tumour and individual segmental anatomy can be depicted in a threedimensional format. As such, three dimensional (3D) liver imaging helps to design an individualised resection, tailored to the topographical relationship between individual segmental anatomy and tumour tissue present. Three dimensional liver imaging is of most practical value if a resection of one or more segments or sectors is considered, especially in the right hemiliver. In these cases, 3D liver imaging can demonstrate the precise location of the scissuras to the surgeon pre-operatively.

Location of the mandibular center of autorotation in maxillary impaction surgery

Controversy exists about the location of the center of autorotation of the mandible after maxillary impaction surgery. This investigation focuses on the problems associated with locating that center of autorotation and identifies factors that can increase the probability of accurately identifying its location for predicting surgical outcomes. The reliability of the Rouleaux technique for calculating the centers of rotation is established and is shown to be acceptable, as long as the landmarks used for determining the center are properly selected, and the magnitude of the rotation required is sufficient. The location of the centers of autorotation of the mandibles after maxillary impaction surgery for 46 patients was used to investigate the errors associated with landmark selection and amounts of rotation. Although there is much variation in its location, the center does not lie within the body of the condyle but instead lies away from the condyle. Guidelines for maximizing the reliability of predicting surgical outcomes on the basis of autorotation of the mandible after maxillary impaction surgery are given.

The center of mandibular rotation in maxillary impaction surgery

The center of mandibular rotation in maxillary impaction surgery

Nasal dimensional changes associated with maxillary impaction surgery

Nasal dimensional changes associated with maxillary impaction surgery

Lip and Tongue Postures Following Maxillary Impaction Surgery

Conclusion: Surgical impaction of the maxilla for patients with vertical maxillary excess and associated skeletal, anterior openbite, is often accompanied by modifications in lip and tongue posture and tongue functions during swallowing. Patients differ in adaptive responses to maxillary surgery for skeletal openbite conditions. Myofunctional therapy for retained problems of lip incompetence has been demonstrated to be effective in selected patients. and may also influence tongue adaptations postoperatively. Our experience with the VME [vertical maxillary excess] osteotomy patients reported in this study should encourage the inclusion of the myofunctional clinician on multidisciplinary teams dealing with facial variations. The myofunctional clinician should follow the lead of Case (1982, IJOM) in emphasizing that therapy to improve oral posturing can benefit the patient both in cosmetic and psychosocial areas.

Mandibular movement during autorotation as a result of maxillary impaction surgery

With increasing use of maxillary surgery to reduce vertical dimension, it would be appropriate to evaluate methods of predicting autorotation of the mandible. Experimental data derived from edentulous patients using metallic implants embedded in occlusal wax rims matched geometrically analyzed clinical data accumulated from twenty-three patients treated by maxillary impaction procedures. The center of rotation of mandibular autorotation during maxillary surgical impaction has been represented in the literature as the center of the condyle. Our evidence with lateral head films taken in centric occlusion supports a different instantaneous center of rotation located within the mastoid region. Modification of prediction tracing techniques by orthodontists and oral surgeons engaged in maxillary surgery could be indicated.