Magnitude Of Relapse Research Articles

Patient-specific Le Fort I Osteotomy Plates are More Stable than Stock Plates in Patients with Cleft Lip and Palate.

There is evidence that patient-specific plate fixation for Le Fort I osteotomies (LFI) is more stable than traditional plates. The purpose of this study was to evaluate stability of LFI in patients with cleft lip and palate (CLP) and determine stability differences between patient-specific and stock plates. Consecutive patients with CLP who underwent isolated LFI by one surgeon (BLP) between 2016 and 2021 were included. The predictor variable was type of plate used for fixation (patient-specific or stock). The outcome variable was magnitude of relapse in the vertical (Nasion-A point) and horizontal planes (Basion-A point) at one year post LFI using 3-dimensional cone beam computed tomography. Statistical analysis included Independent Samples T-test, Mann-Whitney U, Fisher's exact and Chi-square tests. P<0.05 was significant. The sample included 63 subjects; 23 (36.5%) in the patient-specific group and 40 (63.5%) in the stock group. Groups were comparable by sex, race, age at operation, cleft type, presence of pharyngeal flap and magnitude of horizontal movement (P>0.136, all). Subjects who underwent patient-specific plate fixation were less likely to have ≥1mm change at one year in the horizontal (4.3% vs. 50.0%, p<.001) and vertical planes (4.3% vs. 65.0%, P<.001) compared to stock plates. For patients who had >10mm horizontal advancement, the patient-specific plates had significantly less relapse (patient-specific 0.105mm ± 0.317mm vs. stock 1.888mm ± 1.125mm vs, P=.003). Patient-specific plate fixation of LFI is more stable and demonstrates less relapse after one year than stock plates. Therapeutic, III.

Relapse rate and magnitude of relapse after mandibular distraction osteogenesis (MDO) in adult retrognathic patients

ObjectivesThe objective of the present study was to analyze the relapse rate and the magnitude of relapse after mandibular distraction osteogenesis (MDO) using cephalometric measurements. Materials and methodsThe sample comprised 63 patients (49 women, 14 men) with moderate to severe mandibular retrognathia, mean age of 22.6 years, who underwent MDO between 2010 and 2021. Data were collected from CBCTs recorded preoperatively (T0), after the active distraction phase (T1), and 12 months after the distraction phase (T2). Two-dimensional cephalometry analyses were performed. ResultsThe mean cephalometric advancement was at T1 for mandibular body length (MBL) 10.30 mm, for mandibular unit length (MUL) 8.00 mm, and for SN-Pog 4.84°. At T2, MUL decreased by 0.26 mm (p = 0.14), and MBL by 0.22 mm (p = 0.39). A positive correlation between the magnitude of distraction and the magnitude of relapse was identified (MBL p = 0.045; MUL p = 0.002). ConclusionsMDO is a reliable method of advancing the mandible in retrognathic adult patients.

Rotational relapse of anterior teeth following orthodontic treatment and circumferential supracrestal fiberotomy

Background/purposeSeveral factors cause relapse of orthodontically de-rotated teeth after appliance removal. Circumferential supracrestal fiberotomy (CSF) may release the tension on the supra-alveolar fibers following tooth de-rotation, thereby reducing the relapse risk. However, careful identification of the amount and location of relapse enables proper clinical evaluation. We aimed to determine the amount of orthodontic relapse following CSF for de-rotated anterior teeth. Materials and methodsEleven patients with 90 orthodontically de-rotated anterior teeth were enrolled. CSF was performed after orthodontic treatment, during fixed retainer placement. Rotational correction and relapse were measured on three casts (preorthodontic treatment, cast 1; postorthodontic treatment + CSF, cast 2; and 12-month follow-up, cast 3). The Wilcoxon test was used to assess significant differences in the tooth rotation angles between casts 1 and 2 and casts 2 and 3. The relationship between the magnitude of relapse and pretreatment severity of rotation was assessed by the point biserial correlation test. The Mann-Whitney U test helped in identifying significant differences in the amount of relapse between maxillary and mandibular teeth. ResultsThe mean amount of rotational correction was 14.05°, while the mean amount and percentage of relapse were 1.1° and 10.8%, respectively [0.81° (8%) and 1.44° (14%) for maxillary and mandibular teeth, respectively]. The relapse amount was proportional to the pretreatment rotation severity, and it was larger for the mandibular canines. There was no significant difference in the amount of relapse between the maxillary and mandibular teeth (P = 0.07). ConclusionPost-treatment rotational relapse of anterior teeth subjected to CSF was minimal and statistically insignificant after 1 year of follow-up. This validates the promising results of CSF when combined with appropriate mechanical retention for an adequate period.

Relapse tendency after orthodontic correction of upper front teeth retained with a bonded retainer.

To investigate the amount and pattern of relapse of maxillary front teeth previously retained with a bonded retainer. The study group consisted of 135 study casts from 45 patients. Recordings from study models before treatment (T1), at debonding (T2), and 1 year after removal of the retainer (T3) were present. All patients had been treated with fixed edgewise appliances. The irregularity index (sum of contact point displacement [CPD]) and rotations of front teeth toward the raphe line were calculated at T1, T2, and T3. The mean irregularity index at T1 was 10.1 (range 3.0-29.9, SD 5.4). At T2 it was 0.7 (range 0.0-2.1, SD 0.7), and at T3 it was 1.4 (range 0.0-5.1, SD 1.2). Fifty-five teeth in 42 patients were corrected more than 20 degrees between T1 and T2 (mean correction 31.4 degrees range 20.0-61.7), and mean relapse in this group was 7.3 degrees (range 0.0-20.5). Regarding alignment of the maxillary front teeth, the contact relationship between the laterals and centrals seems to be the most critical. A significant positive correlation was found between the amount of correction of incisor rotation and the magnitude of relapse but not between the amount of correction of CPD and the magnitude of relapse. Eighty-four percent of the overcorrected CPDs returned to a desired position. Minor or no relapse was noted at the 1-year follow-up.

The relationship between the curve of spee,relapse, and the Alexander discipline

Exaggerated curves of Spee are frequently observed in dental malocclusionsthat present with deep vertical overbites. During orthodontic treatment such excessive curves of Spee are usually leveled and, in most instances, this leveling will result in a reduction of the anterior overbite. The Alexander Discipline provides a good example of modern straight-wire orthodontic techniques that purport an ability to treat abnormal variations in the depth of the occlusal plane. The records of 31 randomly selected patients treated by nonextraction with the Alexander Discipline were studied. The results show that the Alexander Discipline levels the curve of Spee in Class II, Division I deep-bite cases and that when relapse occurs, the curve of Spee returns to a lesser extent than was present before orthodontic treatment. With the Alexander Discipline, a pretreatment curve of Spee that is not completely level posttreatment has a slightly higher incidence and magnitude of relapse than a pretreatment curve of Spee that is completely level posttreatment. This study indicated that, based on the pretreatment curve of Spee, there is no ability to predict relapse in mandibular intercanine width, overbite, overjet, mandibular incisor irregularity, and arch length in Class II, Division I deep-bite cases treated with the Alexander Discipline.

Long-term skeletal stability after rigid fixation of Le Fort I osteotomies with advancements

The purpose of this retrospective study was to evaluate relapse, comparing large and small maxillary advancements with four-plate rigid fixation and without bone grafting. All patients had obstructive sleep apnea, and underwent bimaxillary surgery. Standardized cephalometric analysis by two separate examiners was performed on serial radiographs of 20 patients immediately before surgery, and at 1 week and at least 6 months postoperatively (mean 18.5 months). The group was divided into three subsets to determine whether the magnitude of maxillary advancement correlated with the magnitude of relapse. In group 1 (≤ 6 mm, n = 4), the average advancement was 4.7 ± 0.8 mm, with a mean relapse of 0±0.6 mm. In group 2 (7–9 mm, n = 9), the average advancement was 8.2 mm ±0.9, with a mean relapse of 0.7±1.5 mm. In group 3 (≥10mm, n = 7), the mean advancement was 12.3±2.8 mm, with a mean relapse of 1.9±1.8 mm. There was no statistical difference in the measured relapse among the groups.