جستجوی مقالات مرتبط با کلیدواژه "skeletal class 2" در نشریات گروه "پزشکی"

Functional appliances such as twin blocks are widely used to treat skeletal Class II malocclusions. Myofunctional effects are one of the critical features of these appliances. The present study aimed to investigate the muscular effects of clear and traditional twin blocks.

In this randomized clinical trial, 60 skeletal Class II division 1 patient were randomly divided into two groups: clear twin block (CTB) and traditional twin block (TTB). Electromyographic (EMG) evaluation of masseter, anterior temporalis, orbicularis oris, and mentalis muscles was carried out during deglutition, rest, whistling, and forced occlusion before insertion (T1) and six months (T2) after insertion of the appliance. Data were analyzed using independent t-test, paired t-test, and Wilcoxon’s signed rank at the 0.05 significance level.

There were no significant differences in T2 values between the groups (P>0.05). The intragroup comparisons showed a significant change from T1 to T2 in the CTB group for the clenching of the masseter muscle and in the TTB group for swallowing and rest position of the anterior temporalis muscle and swallowing of the masseter muscle (P<0.05).

Both CTB and TTB changed the muscular activity of circumoral muscles. No significant difference was found when the post-treatment muscular activity of the two groups was compared.

The present study aims to assess the differences in the condyle position for two skeletal classes using Cone-Beam Computed Tomography (CBCT) reconstructions for both sides and genders.

In this cross-sectional descriptive study, the CBCT images of 96 patients (20-60 years) were assessed. The participants were divided according to their Angle malocclusion classifications (Angle Classes I and III). The variables of the Anterior-Posterior position of the Condyle (APC), condylar angle in the axial plane (ACA), the Lateral Position of the Condyle in the axial plane (LPC), the Vertical Position of the Condyle (VPC), condylar angle in coronal dimension (CCA), and the difference of APC and VPC on both sides were measured. The measurements were analyzed using a one‑way ANOVA and Tukey’s post hoc test.

The variables of APC, LPC, ACA, VDC, and the difference of the APC on both sides in the two skeletal classes were similar. The VPC and CCA were greater in Class III than in Class I. All variables representing the 3D position of the condyle were similar in men and women, as well as on the right and left in both skeletal classes, I and III.

Based on the 3D evaluation results of the condylar position, the skeletal classes III and I differed in the VPC and CCA; however, for the rest variables, there were no statistical differences.

The aim of this study was to compare the dento-skeletal stability between one and three-screw fixation of mandible following bilateral sagittal split osteotomy (BSSO) in skeletal class 3 patients.

Healthy patients with skeletal class 3 malocclusion in Mashhad, Iran, from August 2020 to May 2021 were undergone mandibular setback through bilateral sagittal split osteotomy. Rigid fixation was performed in one group with one-screw technique, and three-screw fixation was done in another group. Cephalogram x-rays were prepared and analyzed in three stages: before surgery (T0), one week after the surgery (T1), and six months postoperatively (T2). The linear and angular alterations of chosen multivariate skeletal and dental variables were evaluated and statistically compared in all three periods.

This study included a total of 20 patients, 12 of them were female (60%). Patients in the one-screw fixation group had a mean age of 20.6 ± 2.2 years old, whereas those in the three-screw fixation group were 21.5 ± 2.8 years old, with no statistically significant difference. Both groups had excellent mandibular stability six months following surgery. No statistically significant differences were observed in the postoperative skeletal and dental changes between the two techniques.

Fixation of the mandible following the setback surgery by the BSSO technique with the one-screw fixation method may be accomplished effectively, and the therapeutic outcomes are comparable to those obtained with the traditional 3-screw fixation approach.

We aimed to compare the emergence from anesthesia between the isolated mandibular setback and bimaxillary orthognathic surgeries in Skeletal Class III Patients.

All healthy patients with skeletal class III deformity admitted to Mashhad Dental School, Mashhad, Iran from the years 2017 to 2018 were included in this study. They were candidates for either bimaxillary orthognathic surgery (Bimax surgery) through a combination of mandibular setback surgery plus maxillary advancement or isolated mandibular setback (Monomax surgery). The predictor variable was the type of jaw displacement and anesthesia duration, while the outcome variable was the duration of emergence from general anesthesia. The duration of emergence from anesthesia was calculated from the time the patient was transported to the recovery room until the time of safely discharging from the recovery room. For statistical analysis, the significance level was set at 0.05 using SPSS 21.

A total of 81 consecutive patients, comprising 45 (55.6%) males and 36 (44.4%) females, with an average age of 23.15±4.58 years were recruited. Among the participating patients, 56 (69.1%) underwent bimaxillary surgery while the other 25 (30.9%) were treated with Monomax surgery. Regardless of the type of performed surgery, the duration of general anesthesia was the only factor to be significantly correlated to the length of emergence from anesthesia (P= 0.001). 

Increased exposure time to general anesthesia might result in a longer emergence from anesthesia, despite the type of performed orthognathic surgery. Further clinical trials are needed to support the relevancy.

We aimed to evaluate the possibility of temporomandibular joint (TMJ) dysfunction following mandibular advancement surgery in skeletal class 2 patients.

All healthy non-syndromic patients with Class 2 deformity, who were eligible for mandibular advancement surgery, were included in this before-after quasi-experimental study. The main intervention was mandibular advancement through bilateral sagittal split osteotomy (BSSO). Maxillary impaction or setback surgery using LeFort 1 osteotomy was simultaneously performed in some cases. Variables such as TMJ pain, clicking, crepitus, or any other type of sounds or complaint as well as the amount of maximum mouth opening (MMO) were evaluated before surgery and two months postoperatively.

Thirty patients including 15 men and 15 women with a mean age of 23.3 ±2.7 yr were studied. The mean amount of mandibular advancement displacement was 3.30 ± 0.87 mm. The rate of TMJ dysfunctions and complaints was relatively low two months postoperatively when compared to the preoperative state. Postoperative evaluation demonstrated that there was no significant correlation between the presence of TMJ symptoms and dysfunctions and the type of surgery. After treatment was completed, the mean MMO reduced significantly from 39.03±5.86 to 38.12±6.05 (P<0.001).

Mandibular advancement with BSSO surgery in skeletal class 2 patients did not clinically lead to TMJ dysfunctions. Among all the investigated factors, only preoperative pain, noises, or complaints were proven to have predictive value for postoperative TMJ dysfunction.

The purpose of Dentofacial Deformity Treatment is to achieve the proper aesthetic and functional occlusion results. Conventional orthognathic surgery involves a long-term orthodontic phase before surgery for about 18 months, in which patients’ facial appearance worsens and their motivation decreases. In the SFA (surgery first approach) method, the surgery is performed before orthodontics and orthodontic therapy is performed to improve dental occlusion and final settlement. Two main advantages of this method are the reduction of the therapy period and the initial improvement in the patient’s facial appearance. The SFA has certain benefits, especially in Class 3 malocclusion. In this case report, a 19-year-old girl with a relatively severe Class 3 malocclusion with skeletal discrepancy due to a mandibular prognathism and maxillary retrognathism, and asymmetrical face with chin deviation to left is presented with a unilateral posterior cross bite which was effectively treated using the SFA protocol. The SFA therapy was performed by removing orthodontics before surgery, followed by maxillary advancement surgery, and posterior maxillary impaction and postoperative orthodontic sets to dental alignment and settling the occlusion. Despite the overall reduction in the orthodontic therapy period to less than 9 months, good results and functional occlusion were obtained.

BACKGROUND 

Since aesthetic issues are the most important causes of referring skeletal class III patients to surgeons, investigating the impact of orthognathic surgeries on improving patient profiles increases the quality of treatment and quality of life. 

METHODS 

In a retrospective observational-analytical study, 25 patients older than 18 years with class III skeletal malocclusion who had gone under both orthodontic and double-jaw orthognathic treatment were enrolled. Cephalometric imaging interval was before and at least 6 months after surgery. By defining a number of points and coordinate axes (X-Y), a criterion for comparing hard and soft tissue changes was obtained. These measurements were coordinated, linear and angular. The quantitative data were compared with data obtained using the Likert Scale Questionnaire by means of electronic “Google Forms” that was completed by orthodontists (n=5) and maxillofacial surgeons (n=5) to rank improvement in post-surgical profiles for both cephalometry and photography from poor to pleasant. Spearman Correlation Analysis was conducted between the quantitative and qualitative data.

Vertical changes of point B and horizontal changes of point PNS showed correlation with improvement of patient profile. Changes in N-Pog line (R=-0.4), mandibular plane angle (R=-0.4) and nasolabial angle (NLA) (R=0.38) were significantly correlated with improvement of profiles. 

In orthognathic double-jaw surgery on patients with skeletal Class III, forward movement of maxilla, upward positioning of mandible (decreasing anterior facial height), decreasing mandibular plane angle and increasing nasolabial angle would result in a better profile.