The nature of Class II relapse after Herbst appliance treatment: a cephalometric long-term investigation

The purpose of this investigation was to assess the number of, and the interrelation between, skeletal and dental components that contribute to Class II relapse after Herbst treatment. A comparison was made between 15 relapse and 14 stable cases at least 5 years after treatment. Lateral cephalograms taken before and immediately after Herbst treatment, as well as 6 months and 5 to 10 years after treatment, were analyzed. The results revealed that relapse in the overjet and sagittal molar relationship resulted mainly from posttreatment maxillary and mandibular dental changes. In particular, the maxillary incisors and molars moved significantly (p less than 0.05) to a more anterior position in the relapse group than in the stable group. The interrelation between maxillary and mandibular posttreatment growth was favorable and did not contribute to the occlusal relapse. It is hypothesized that the main causes of the Class II relapse in patients treated with the Herbst appliance were a persisting lip-tongue dysfunction habit and an unstable cuspal interdigitation after treatment.     

Palatally displaced upper lateral incisors: relapse after orthodontic treatment and its correlation with dentoskeletal morphology

The purpose of the present study was to determine whether the relapse tendency of the palatally positioned upper lateral incisor differs in patients treated with or without premolar extraction, and if there is any correlation between the amount of upper lateral incisor relapse and pretreatment dentoskeletal morphology or post-treatment changes. Forty-six patients with bilateral palatally displaced upper laterals who also exhibit maxillary dental constriction were separated into two groups: a premolar extraction (30 cases) group and a non-extraction (16 cases) group. All subjects had undergone orthodontic treatment with quad helix and edgewise appliances, followed by a 2-year retention period. Differences in the amount of the upper lateral incisor relapse and their correlations with the dentoskeletal morphology before and after treatment were determined on the lateral and postero-anterior cephalograms and dental casts. Results revealed that the upper lateral incisor relapse in the extraction group was significantly greater (p=0.0002) than the relapse in the non-extraction group. There was a positive correlation between incisor relapse and the distance of lateral incisor movement in both groups (r=0.539; p=0.030). Relapse in the non-extraction group was correlated with the widths of the upper dental arch (r相似文献   

20例错牙合正畸治疗和保持后的模型分析研究

目的：评估错He畸形经治疗和保持后牙弓的变化情况，为临床治疗同类错He提供依据。方法：选择拔除4颗第一双尖牙的患者20例，采用方丝弓技术治疗。对治疗前后和保持器停截1年后的模型进行测量。结果：治疗前后除上下牙弓尖牙宽度增加外，其余指标均不同程度减少，去除保持器1年后，上下尖牙宽度和前牙覆He，覆盖出现复发，而上下牙弓中，后段宽度和上下牙弓长度继续减少。结论：治疗后上颌尖牙宽度净增加量较下颌稳定，经治疗和保持后，上下牙弓宽度和长度并非一定会复发。     

Longitudinal dento-skeletal changes in UCLP patients following maxillary distraction osteogenesis using RED system

Longitudinal dento-skeletal changes in unilateral cleft lip and palate (UCLP) patients following maxillary distraction osteogenesis using the rigid external distraction device (RED) were analyzed. Twelve Japanese non-syndromic UCLP patients who underwent maxillary distraction at the mean age of 16.4 years were used as subjects. Serial sets of lateral cephalograms, taken at 4 stages: 1) before osteotomy, 2) immediately after distraction, 3) 6 months and 4) 12 months post-osteotomy, were analyzed. Statistical analyses, including a paired t test, Pearson correlation analysis and stepwise linear regression analysis, were performed to distill characteristic dento-skeletal changes. In accordance with maxillary advancement, significant amounts of up-forward movement of the nasal bone, mandibular rotation and maxillary dental changes were observed. Maxillary dental changes were significantly related to the amount of mandibular rotation and force system of maxillary traction. Significant dento-skeletal relapse was found to occur during the 0-to-6-month follow-up period, but not in the 6-to-12-month follow-up period. Maxillary relapse was significantly related to the amount of maxillary advancement and severity of pre-surgical maxillary hypoplasia, while mandibular relapse was significantly related to maxillary dento-skeletal relapse. Successful clinical application of this procedure therefore requires consideration of both the surrounding dento-skeletal changes and the traction force system.     

Analysis of the development of the arch form after treatment using "ARCAD'Image" software

The dental arch post-therapeutic modification plays a significant role in relapse phenomenon. This article describes the design work of the dental arches used as a base for the study of modifications that have arisen during orthodontic treatment then during the retention stage using pre-formed arch wires. ARCAD'Image software tries to design the patients dental arches by submitting a linear regression mathematical design on some characteristic landmarks of a photograph of the buccal impression. The designed dental arch can then be considered as being the closest/nearest to the patients morphology. This model enables the practitioner to bend the arch wire and is used as a base for the study of arch shape modifications. Our study shows that the term "relapse" appears to be used excessively; it would be more matter of evolution due to changes in neuro-muscular balance along with facial aging.     

Stability of the mandible following advancement: a comparison of three postsurgical fixation techniques

This study examines short-term stability of the mandible following mandibular advancement surgery by means of three standard techniques of postsurgical fixation. Twenty-two adult female rhesus monkeys (Macaca mulatta) underwent sagittal ramus advancement osteotomy of approximately 4 to 6 mm. Six animals had dental maxillomandibular fixation alone. Six animals had dental plus skeletal maxillomandibular fixation with circummandibular wires connected to pyriform aperture wires. Ten animals had rigid internal fixation with bicortical bone screws between the proximal and distal segments without maxillomandibular fixation. Radiographic cephalograms with the aid of tantalum bone markers and dental amalgams were analyzed during the first 6 postoperative weeks to evaluate skeletal and dental stability. Rigid internal fixation and the use of dental plus skeletal maxillomandibular fixation were both equally effective in the prevention of postsurgical relapse. However, in the animals in which only dental maxillomandibular fixation was used, statistically significant changes (relapse) occurred when compared with either of the other groups.     

下颌前突患者升支矢状劈开截骨术后骨性复发因素的探讨

目的：探讨下颌前突患者升支矢状劈开截骨术（bilateral sagittal split ramus osteotomy,BSSRO)术后骨性复发的相关因素。方法：以术后长期面角（∠NP－FHT4－3）的变化作为因变量,选择术前术后12项自变量,对两者之间的关系进行多元线性相关及偏相关分析。结果：术后长期下颌平面角（∠MP－FHT4－3）、术前正畸疗程、术后观察期与因变量呈显著负相关关系（r分别为－0．568、－0．406、－0．400,P＜0．01－0．05）。结论：下颌前突患者BSSRO术后的骨性复发非常有限,术前正畸疗程、术后下颌旋转与术后矢状颌位的稳定相关。     

Dental and skeletal changes following sagittal split osteotomy for correction of mandibular prognathism

Skeletal and dental changes were examined in 15 patients presenting with a Class III malocclusion treated by a sagittal split osteotomy. All patients received orthodontic treatment with Straightwire appliances both prior to and following surgery. These appliances were also used for fixation. The lower incisors were proclined by 8.4 degrees before surgery with little change in upper incisor inclination. With surgery, there was a mean reduction of 4.3 degrees in the angle SNB. Following surgery, the relapse in mandibular position was minimal and was not related to the dental changes during this period. Changes in the vertical skeletal parameters were generally small. The individual cases exhibited a wide variation in the changes.     

Dental and skeletal changes following surgically assisted rapid maxillary expansion

The aim of this study was to evaluate skeletal and dental changes after surgically assisted rapid maxillary expansion (SARME). Clinical trials were carried out that assessed skeletal and dental changes through cephalograms, computer tomographs or dental casts. No other simultaneous treatment during the active expansion period was accepted. Electronic databases (Pubmed, Medline, Medline In-Process & Other Non-Indexed Citations, All Evidence-based Medicine Reviews, Embase, Web of Science and Lilacs) were searched. Abstracts which appeared to fulfil the selection criteria were selected by consensus. The original articles were then retrieved and evaluated with a methodological checklist. Their references were hand searched for possible missing articles. Only 12 articles fulfilled the selection criteria. All presented methodological flaws. An individual methodological analysis of these articles was made. Expansion was greater at the molars and diminished progressively to the anterior part of the dental arch in all the evaluation periods. Vertical and sagittal skeletal changes were nil or not clinically significant. The nasal portion of the maxillary complex showed an increase in dimensions thereby improving nasal patency. An overall dental relapse of 0.5-1 mm is reported after 1 year of orthodontic treatment. The conclusions should be considered with caution because only a secondary level of evidence was found.     

Relapse of incisor crowding: A visit to the prince of salina

The management of the retention period after comprehensive orthodontic treatment is of great importance, as a primary goal of clinician. Considerable controversy still surrounds the problem of stability after the retention period. Many studies analyze factors associated to the presence of crowding or incisor irregularity and find predictive features on its relapse. Most studies have reported little o no correlation between the treatment changes in the biological parameters - clinical, biometric (irregularity index, intermolar width, intercanine width, arch length, overjet, overbite), or cephalometric variables- that ocurred and the posttretament and postretention changes that may predict their future development. This article provides a bibliographical overview on the relapse of dental alignment in treated cases. In a brief historical introduction, the first studies on the long-term stability of orthodontic results are analysed. The article then goes on to assess studies that focus attention on anteroinferior alignment before finally studying relapse of upper crowding. It concludes by making some final comments in the light of the bibliography provided and the differents schools regarding retention needs and methods. Key words:Retention, stability, irregularity, dental alignment.     

Distal movement of mandibular molars in adult patients with the skeletal anchorage system.

The skeletal anchorage system (SAS) consists of titanium anchor plates and monocortical screws that are temporarily placed in either the maxilla or the mandible, or in both, as absolute orthodontic anchorage units. Distalization of the molars has been one of the most difficult biomechanical problems in traditional orthodontics, particularly in adults and in the mandible. However, it has now become possible to move molars distally with the SAS to correct anterior crossbites, maxillary dental protrusion, crowding, and dental asymmetries without having to extract premolars. This study evaluated the treatment and posttreatment changes during and after distalization of the mandibular molars. In 15 adult patients (12 women and 3 men), a total of 29 mandibular molars were successfully distalized with SAS. The amount of distalization and relapse and the type of tooth movement were analyzed with cephalometric radiographs and dental casts. The average amount of distalization of the mandibular first molars was 3.5 mm at the crown level and 1.8 mm at the root level. The average amount of relapse was 0.3 mm at both the crown and root apex levels. Of 29 mandibular molars, 9 were tipped back, and the others were translated distally in accordance with the established treatment goals. SAS is a viable modality to move mandibular molars for distally correcting anterior crossbites, malocclusions characterized by mandibular anterior crowding, and dental asymmetries.     

Relapse following mandibular advancement with dental plus skeletal maxillomandibular fixation

This study examines the short-term stability of the mandible following mandibular advancement surgery in which skeletal suspension wires were used in addition to dental maxillomandibular fixation. Twenty adults underwent sagittal ramus osteotomies. No concomitant surgical procedures were performed. Maxillomandibular fixation consisted of wiring between the upper and lower orthodontic brackets and circummandibular wires connected to the piriform aperture or anterior nasal spine wires for eight weeks. Cephalograms were analyzed during this period to evaluate skeletal stability. A statistically insignificant mean horizontal relapse of 8.9% was found at pogonion during the period of fixation. Significant vertical intrusion of the anterior mandible occurred, however, with a mean superior movement of pogonion of 0.83 mm (P less than or equal to 0.05). Dental changes noted were uprighting of the maxillary incisors and flaring of the mandibular incisors. In comparison with the results of other studies in which dental maxillomandibular fixation was used alone, the results of this study indicate that the use of skeletal suspension wires is advantageous in the prevention of horizontal skeletal relapse.     

Positional changes after mandibular advancement by sagittal split osteotomies and wire osteosynthesis. Do combined orthodontics and the Dal Pont modification of the buccal osteotomy contribute to long-term stability?

Thirty-five cases of sagittal split ramus osteotomies with wire osteosynthesis as the exclusive procedure used to correct a dentoskeletal Class II deformity, were selected to form a homogeneous group for cephalometric evaluation of the short- and long-term, skeletal and dental changes. The group was statistically described as having severe micromandibulism, mild micromaxillism and mild dento-alveolar maxillary protrusion. The skeletal relapse within the first postoperative year was due to horizontal and dorsocranial rotational changes of the tooth-bearing segment. The joint-bearing segment rotated ventrocranially. As an overall result, the mandibular body was not lengthened but advanced. The relapse at the occlusal level was considerably less, partly due to the rotational component of the skeletal relapse mechanism, partly due to the compensating retroclination of the upper anterior teeth. With the condyles correctly repositioned at surgery, no relationship could be found between postoperative changes in condylar position and skeletal relapse. There was no difference in the average amount of skeletal relapse between the subgroup with the Dal Pont modification of the buccal osteotomy and the subgroup with the buccal osteotomy directed to the mandibular angle. The average skeletal relapse was greater in the combined surgical orthodontic cases, due to increased alveolar tooth mobility.     

Predictors of postretention stability of mandibular dental arch dimensions in patients treated with a lip bumper during mixed dentition followed by fixed appliances

Objective:To identify which dental and/or cephalometric variables were predictors of postretention mandibular dental arch stability in patients who underwent treatment with transpalatal arch and lip bumper during mixed dentition followed by full fixed appliances in the permanent dentition.Materials and Methods:Thirty-one patients were divided into stable and relapse groups based on the postretention presence or absence of relapse. Intercuspid, interpremolar, and intermolar widths; arch length and perimeter; crowding; and lower incisor proclination were evaluated before treatment (T0), after lip bumper treatment (T1), after fixed appliance treatment (T2), and a minimum of 3 years after removal of the full fixed appliance (T3). Logistic regression analyses were performed to evaluate the effect of changes between T0 and T1, as predictive variables, on the occurrence of relapse at T3.Results:The model explained 53.5 % of the variance in treatment stability and correctly classified 80.6 % of the sample. Of the seven prediction variables, intermolar and interpremolar changes between T0 and T1 (P = .024 and P = .034, respectively) were statistically significant. For every millimeter of increase in intermolar and interpremolar widths there was a 1.52 and 2.70 times increase, respectively, in the odds of having stability. There was also weak evidence for the effect of sex (P = .047).Conclusions:The best predictors of an average 4-year postretention mandibular dental arch stability after treatment with a lip bumper followed by full fixed appliances were intermolar and interpremolar width increases during lip bumper therapy. The amount of relapse in this crowding could be considered clinically irrelevant.     

Changes in the curve of Spee with treatment and at 2 years posttreatment.

The purposes of this study were to determine pretreatment skeletal and dental patterns related to curve of Spee depth, evaluate changes in the curve of Spee with treatment and the effects on dentofacial structures, and determine factors associated with the stability of the curve of Spee after treatment. Lateral cephalograms and dental casts were evaluated for 24 white male and 26 white female patients at pretreatment, posttreatment, and at least 2 years postretention. All patients had mandibular permanent second molars and premolars erupted and in occlusion. The following variables were correlated with increased pretreatment curve of Spee depth: low Frankfort-mandibular plane angle, deep overbite, increased overjet, and Class II molar malocclusion. No significant differences were found in pretreatment curve depth between male and female patients or between right and left sides. Leveling the curve of Spee was accomplished by uprighting the molars, extruding the premolars, and intruding or flaring the incisors. Extraction and nonextraction cases demonstrated no significant differences in the amount of curve relapse. Increased curve relapse was correlated with postretention increases in overbite, irregularity index, and patients given removable retainers. Overall, the curve of Spee was relatively stable after treatment, with only a 16% relapse of the leveled curve.     

A computerized measurement of dental relapse following orthognathic surgery.

A computer-programmed osteotomy package was used to measure agreed values from lateral cephalograms preoperatively, postoperatively, and during the follow-up period. The variable representing the postoperative cephalometric analysis predicted by the program was included for further comparisons. The results were used to measure the degree of dental and skeletal relapse during the follow-up period, but only the dental relapse is discussed in the present study. There was a statistically significant proclination of the maxillary anterior teeth postoperatively that continued during the mean follow-up period of 16 months.     

Stability of mandibular advancement osteotomy using rigid internal fixation

Forty-three patients who underwent surgical lengthening of the mandible using an inverted L osteotomy, bone grafting, and rigid internal fixation between the mandibular segments were evaluated by retrospective cephalometric analysis for longitudinal skeletal and dental changes. Postoperative response (means = 1 year 9 months) was found to demonstrate a high level of stability with some individual variability. No propensity for relapse was observed in any postoperative time interval. Condylar repositioning postoperatively appeared to be an important factor in those patients who exhibited any relapse tendency. Overall postoperative stability of this surgical/fixation technique appears to be significantly improved compared with previously documented techniques.     

Stability of simultaneous maxillary and mandibular osteotomy for treatment of class III malocclusion: an analysis of three-dimensional cephalograms.

PURPOSE: The current investigation was undertaken to study the three-dimensional (3-D) stability of simultaneous maxillary advancement and mandibular setback using rigid fixation. The study also aimed to analyse the factors involved in postsurgical relapse by evaluation of changes in various parameters. PATIENTS: Twenty-five cases were evaluated of simultaneous Le Fort I maxillary advancement and mandibular setback using rigid fixation. METHODS: Preoperative, immediate and 6-month postoperative skeletal and dental changes were analysed using 3-D cephalograms obtained from biplanar stereoradiography. Maxillary fixation screws were used as landmarks to evaluate postoperative stability. RESULTS: The mean maxillary advancement was 3.7 mm. Relapse in the sagittal, vertical, and transverse planes was not detectable in the maxilla (p > 0.05). However, for an average mandibular setback of 5.7 mm, mean mandibular relapse was 1.1 mm or 19.3% anteriorly (p < 0.05). Surgical or postsurgical skeletal changes in the maxilla had no detectable influence on mandibular relapse (p > 0.05). Vertical alterations of the facial skeleton achieved surgically predicted the mandibular relapse (R2 = 0.27, p < 0.05). CONCLUSION: Maxillary advancement and vertical changes of +/- 2 mm did not influence the postoperative stability of the mandible. Relapse of the mandible seems to be influenced mainly by the amount and direction of the surgical alteration of mandibular position.     

安氏Ⅱ类1分类拔牙病例正畸治疗后后牙关系的稳定性研究

目的　探讨安氏Ⅱ类1分类患者正畸治疗前、后后牙关系的变化趋势,分析可能影响后牙关系复发的因素。方法　选取采用拔牙治疗的安氏Ⅱ类1分类患者29例,其中男12例,女17例。根据ANB角进一步分为牙性Ⅱ类14例,骨性Ⅱ类15例。分别对其正畸治疗前、后进行模型测量和X线头影测量。结果　所有患者的Ⅱ类磨牙关系在治疗后均得到明显改善,随访时仅有少量复发。牙性Ⅱ类患者治疗后下磨牙近中移动量(4·52±2·15) mm,大于上磨牙移动量(3·62±2·62)mm,而骨性Ⅱ类患者上下磨牙近中移动量相似,但ANB角由治疗前的(6·27± 1·08)°明显减小为(4·64±1·17)°。随访时两类错患者上下颌磨牙均近中移动,且上颌磨牙移动量大于下颌磨牙。多元回归分析提示下颌骨水平向生长和上前牙不齐指数与磨牙关系复发有关。结论　Ⅱ类错患者正畸治疗后磨牙关系较为稳定。牙性Ⅱ类错磨牙关系的解除有赖于上下颌磨牙相对移动调整,骨性Ⅱ类错则依靠上下颌骨间位置关系的改变。有利的下颌生长型和上颌前牙不齐程度等与磨牙关系的保持有密切关系。     

Orthodontic relapse in subjects with varying degrees of anteroposterior and vertical dysplasia.

Fifty seemingly well-treated orthodontic cases were studied by means of pretreatment, posttreatment, and postretention dental casts, lateral cephalograms, and other orthodontic records. The sample was restricted to cases exhibiting anteroposterior and/or vertical dysplasia as revealed by pretreatment dental casts. The sample was divided into a stable group and a relapse group. Each group contained twenty-five cases. A double-blind design was used. The raw data were analyzed by the stepwise discriminant analysis and by the multivariate analysis of variance. On the basis of the results obtained from this study, the following conclusions can be drawn: 1. In seemingly well-treated orthodontic cases, relapse or stability can neither be predicted nor judged from one set of records alone. 2. Relapse or stability of an orthodontic case can be predicted by comparing the posttreatment variables with the pretreatment variables. 3. Relapse or stability of an orthodontic case can be judged by comparing the postretention variables to the posttreatment variables. 4. The PP-GoGn angle and the mandibular intercanine width are the two most important variables associated with orthodontic relapse. 5. Changing the PP-GoGn angle, either by treatment or by growth, was associated with relapse. In other words, changes in the PP-GoGn angle tended to be unstable. This suggests that decreasing the PP-GoGn angle should be avoided. 6. In both the stable and the relapse groups, the mandibular intercanine width decreased postretention. This decrease was associated more with the relapse group than with the stable group. 7. The mandibular intercanine width tended to relapse toward its original pretreatment value. This suggests that, at the end of active treatment, the mandibular intercanine width should be maintained as originally presented. 8. There was no significant interaction between orthodontic relapse (or stability) and Angle Class I and II cases. 9. There was no significant interaction between relapse (or stability), of an orthodontic case, and the sex of the patient. 10. There was no significant interaction between orthodontic relapse (or stability) and whether or not extraction was included as a part of the mechanotherapy. Thus, the pretreatment deep overbite is not necessarily a contraindication to extraction.