Transverse Widening Research Articles

Experimental Study on Neck Cutoff in Meandering River under Variable Discharges

Neck cutoff is a sudden phenomenon that occurs during the evolution of meandering rivers, but its process and mechanism remain unclear. In this investigation, the neck-narrowing process before cutoff, the formation of a new river, and the appropriate conditions for cutoff under constant and variable discharges were studied using experimental methods in a laboratory flume. The results indicated that bank erosion upstream and downstream of the neck was the main factor that triggered cutoff, regardless of whether the discharge changed. The sinuosity of the model river was approximately 7, the ratio of the neck width to the average river width reached approximately 0.43, and the experimental material was nonuniform natural sand. Under the conditions that the unit width discharge ranged from 0.0039 to 0.0069 m2/s and the longitudinal gradient was 1‰, neck cutoff could occur after sufficient bank erosion. When neck cutoff was imminent, the sinuosity of the channel increased and the channel rotated downstream. After neck cutoff, the formation of a new river experienced three stages, namely, the short-term longitudinal scouring stage, the long-term horizontal widening stage, and the long-term transverse widening and normal slow development stage. The discharge resulting in neck scouring was the effective discharge contributing to the cutoff, and this discharge directly affected the cutoff time and position. We attempted to explain the factors leading to neck cutoff from an energy consumption perspective. Neck cutoff was a sudden phenomenon that occurred when the energy consumption of a meandering river increased to its maximum value upon entry to the recession stage from the relative equilibrium stage. To a certain extent, this study is significant in understanding river evolution and neck cutoff.

Skeletal and dental effects of surgically assisted rapid palatal expansion: a systematic review of randomized controlled trials.

Surgically assisted rapid maxillary expansion (SARME) is a surgical technique developed to correct transverse discrepancies in skeletally mature patients. However, there is limited evidence concerning the immediate skeletal and dental changes obtained only due to SARME. The aim of the present systematic review is to investigate the immediate skeletal and dental effects of SARME in adult patients with transverse maxillary hypoplasia. An electronic search of the literature in MEDLINE, The Cochrane Library, Lilacs and Scopus databases was performed. Only randomized controlled trials (RCTs) studies investigating the skeletal and dental effects of SARME procedures in adult patients were included. The included studies received a methodological quality scoring according to the revised Cochrane risk-of-bias tool for randomized trials. The quality of evidence was assessed by means of the Grading Recommendation Assessment, Development and Evaluation (GRADE) system. For each included study and for each analysed parameter, the difference in means and 95 per cent confidence interval was calculated between baseline and immediate post-expansion. A meta-analysis of original outcome data, if possible, was conducted. Nine articles were selected. The methodological quality ratings indicated that one study was at low risk of bias, seven presented some concerns and only one was at high risk of bias. In all the included studies, the SARME procedure resulted in a significant expansion of the maxillary transverse dimension. The meta-analysis compared skeletal and dental inter-molar width before and after treatment: the mean difference was of 3.3 mm (2.8-3.9) and 7.0 mm (6.1-7.8), respectively (P-value less than 0.001). The quality of evidence was low-moderate. SARME is effective in obtaining a significant expansion of the maxillary transverse dimension. However, the immediate SARME effect is mainly a molar expansion rather than a pure bone transverse widening of the maxilla. The review protocol was registered at PROSPERO database with the registration number CRD42018117967.

Three-dimensional soft tissue effects of mandibular midline distraction and surgically assisted rapid maxillary expansion: an automatic stereophotogrammetry landmarking analysis

Studies on mandibular midline distraction (MMD) are mostly performed using conventional research methods. Concerning surgically assisted rapid maxillary expansion (SARME), more research is conducted using three-dimensional (3D) techniques. Research on bimaxillary expansion, the combination of MMD and SARME, is reported sparsely. The main objective of this study was to provide a 3D evaluation of soft tissue effects following SARME and/or MMD. Patients who underwent SARME and/or MMD between 2008 and 2013 were included. Stereophotogrammetry was undertaken at the following time points: preoperative (T1), immediately post-distraction (T2), 1year postoperative (T3). An automatic 3D facial landmarking algorithm using two-dimensional Gabor wavelets was applied for the analysis. Twenty patients who had undergone SARME were included, 12 of whom had undergone bimaxillary expansion. Age at the time of surgery ranged from 16 to 47 years. There was a significant downward displacement of soft tissue pogonion. Furthermore, there was a significant mean increase of 2.20mm in inter-alar width and a non-significant mean increase of 1.77mm in inter-alar curvature point width. In conclusion, automatic stereophotogrammetry landmarking analysis of soft tissue effects showed downward displacement of soft tissue pogonion following bimaxillary expansion and transverse widening of the inter-alar width and a tendency towards an increase in inter-alar curvature point width after SARME.

Correlation between laser welding sequence and distortions for thin sheet structures

Thin ultra-high strength steel shaped as 700 mm long U-beams have been laser welded in overlap configuration to study the influence of welding sequence on distortions. Three different welding directions, three different energy inputs as well as stitch welding have been evaluated, using resistance spot welding (RSW) as a reference. Transverse widening at the ends and narrowing at the centre of the beam were measured. A clear correlation was found between the weld metal volume and distortion. For continuous welds there was also a nearly linear relationship between the energy input and distortion. However, the amount of distortion was not affected by a change in welding direction. Stitching and RSW reduced distortion significantly compared to continuous laser welding.

Segmented therapy in surgery

The combined treatment of severe dentofacial deformities normally consists of at least three steps: The pre- and post-operative orthodontic treatment and the treatment between surgical correction. The accuracy of the surgical planning and especially the surgery itself are crucial for the duration of the postoperative orthodontic treatment. Main reason for the segmentation of the jaws is the acceleration of the orthodontic treatment. In our of 195 bimaxillary cases from three years we have observed the following indications for maxillary segmentation: • Frontal open bite. • Pro- or retrusion of the incisors. • Bolton discrepancies. • Asymmetry of the dental arch. During LeFort I osteotomy we performed the partition in two, three or four parts. We observed the following indications for mandibular segmentation: • Gap closure in dental arches • Transversal discrepancies • Asymmetry of the dental arch • Pro- or retrusion of the lower incisors, often in combination with chin hypoplasia. Beside BSSO we have performed median osteotomies for both transversal widening and reduction. Segmental osteotomies for the correction of pro- or retrusion of the incisors were indicated very often, sometimes with additional distraction procedures. Often we combined the procedure with a correction of the chin by sliding genioplasty anterior bloc rotation or chin wing. These corrections facilitated the orthodontic treatment and reduced postsurgical treatment duration. In cases of exact postoperative intercuspation, only dental retention was necessary.

Abstracts of the IBRA Conference on Surgery of the Head, 6th International Orthognathic Surgery Forum, February 14-15, 2014, Interlaken, Switzerland.

The multi-step treatment of severe dentofacial deformities starts after the termination of skeletal bone growth. In cases of additional transversal discrepancies the SARPE procedure has to be executed at first, followed by the orthodontic alignment of the dental arches. Then the at least three step treatment starts: it consists of the pre- and postoperative orthodontic treatment and the treatment in between surgical correction. This combined treatment may last up to three years and longer. For economic reasons as well as for an increasing motivation of the patient the ‘Surgery First’ concept was developed to reduce treatment time. We take advantage of the Regional Acceleration Procedure (RAP), which is known since Kole published the interdental corticotomy in the crowded lower front to accelerate the orthodontic alignment in the 1950s. Instead of hyrax screws for transversal widening we prefer he application of bone borne devices for SARPE procedures. Fixed appliances treatment starts earlier using RAP effect. Instead of preoperative orthodontic treatment we start with the operation and align the dental arches postoperatively within 6-8 months. Advantages of ‘Surgery First’: • The patient sees the operative results immediately. • Orthodontic treatment is accelerated by RAP effect. • Treatment is completed after 6-8 months, sometimes after 10 months. Disadvantages of ‘Surgery First’: • Orthodontists must be experienced and needs to plan the treatment in advance. • More close cooperation between surgeon and orthodontist is needed. • Orthodontic treatment starts 1-2 weeks after the operation with intervals of two weeks. • RAP effect takes three to four months. The ‘Surgery First’ concept can be performed easily with stable results in Angle Class II and III cases with crowding, frontal compensation and pronounced Spee curve. (Segmented) Bimaxillary osteotomies with or without CWR or CCWR can be performed with additional procedures as chin correction or jaw bone augmentation. The ‘Surgery First’ concept delivers safe results also in open bite cases, elongated front regions, minor transversal discrepancies and asymmetries. In cases of severe facial deformities and transversal discrepancies ‘Surgery First’ cannot be recommended yet.

Oral Rehabilitation of an Edentulous Patient Using Two-Segment Le Fort I Repositioning and Implant-Supported Fixed Prostheses

Anteroposterior (AP) deficiencies present a restorative treatment challenge. Complex, multidisciplinary planning is necessary for the success of the treatment. This clinical report describes an approach to managing a complex complete oral rehabilitation of an edentulous patient with skeletal transverse and AP deficiencies with a history of facial trauma to the left zygomaticomaxillary complex. This was further complicated by a hopeless remaining dentition and pneumatization of the maxillary sinuses. Treatment included initial bony augmentation of the vertically and horizontally deficient maxilla, dental implant placement, provisional restoration in a Class III malocclusion with bilateral posterior crossbite, and Le Fort I osteotomy with transverse widening and advancement to correct the skeletal deficiency. Definitive restoration was accomplished with implant-supported fixed prostheses that provided ideal facial balance and occlusion.

Evaluation of immediate soft tissue changes after rapid maxillary expansion

OBJECTIVE: To evaluate immediate soft tissue changes following rapid maxillary expansion (RME) in growing patients, using cone beam computed tomography (CBCT). METHODS: Twenty-three consecutive patients (10 male, 13 female) treated by RME were selected. Patients were scanned using CBCT prior to placement of the rapid maxillary expander (T0), then immediately following full activation of the appliance (T1). Defined landmarks were then located on the pre- and post-treatment orientated images. Change in landmark position from pre- to post-treatment was then measured. In addition to landmarks, 10 direct measures were made to determine distance change without regard to direction to measure soft tissue change of the lips. RESULTS: Significant transverse expansion was measured on most soft tissue landmark locations. All the measures made showed significant change in the lip position with a lengthening of the vertical dimension of the upper lip, and a generalized decrease of anterior-posterior thickness of both the upper and lower lips. CONCLUSIONS: Significant changes in the soft tissue do occur with RME treatment. There is a transverse widening of the midface, and a thinning of the lips.

Assessment of Surgically Assisted Rapid Maxillary Expansion Regarding Pterygomaxillary Disjunction Using Thin Volume-Rendering Technique: In Variance Analysis and in Reliability, Accuracy, and Validity

To assess surgically assisted rapid maxillary expansion (SARME) with or without pterygomaxillary disjunction using a thin volume-rendering technique in variance analysis and in reliability, accuracy, and validity. Thin volume-rendered images of 68 patients were evaluated preoperatively and 2.87 ± 1.59 months after expansion with respect to dentoskeletal effects. Variance analysis of SARME with pterygomaxillary disjunction showed an important decrease in transverse widening and segmental outward inclination and an increase in vestibular bone plate thickness (premolars) in patients younger than 20 years with bone-borne devices; the greatest increase in transverse widening was in patients with 3-segment osteotomy and tooth-borne devices. Analysis of SARME without pterygomaxillary disjunction showed an important decrease in transverse widening and segmental inward inclination in patients older than 20 years with bone-borne devices; the greatest pterygoid lateral bending was in patients with 2-segment osteotomy and bone-borne devices. The performance of pterygomaxillary disjunction should depend on patient age (ie, treatment with pterygomaxillary disjunction in those >20 years old; treatment without pterygomaxillary disjunction in those <20 years old). Patients with pterygomaxillary disjunction, 3-segment osteotomy, and tooth-borne devices tended to show an increase in transverse widening but at the price of greater attachment loss. Patients younger than 20 years with pterygomaxillary disjunction and bone-borne devices tended to show an increase in vestibular bone plate (premolars) but at the price of decrease in transverse widening.

Long-term 3D cast model study: bone-borne vs. tooth-borne surgically assisted rapid maxillary expansion due to secondary variables

This study aims to compare bone-borne (BB) surgically assisted rapid maxillary expansion (SARME) to tooth-borne (TB) SARME with regard to dentoskeletal effects. Measurements were performed on 3D scanned cast models of 34 patients preoperatively and 20.5 +/- 1.34 months post-expansion. Secondary variables were pterygomaxillary disjunction or not; bimaxillary osteotomy or not and patient age. BB SARME without pterygomaxillary disjunction on patients <20 years led to a symmetric increase in transverse widening; however, simultaneously, to more dental tipping (canines/second molars) and to the biggest overall attachment loss (frontal teeth/premolars), especially, after the performance of bimaxillary osteotomy. TB SARME led to an asymmetric decrease in transverse widening and to more dental tipping (premolars/first molars). In long-term effects, BB SARME led to a symmetric increase in transverse widening; however, at the price of frontal attachment loss, resulting from the initial asymmetric, but bigger, overall transverse widening, the initial major segmental rotation and the necessary orthodontics for tooth arch alignment before and after bimaxillary osteotomy.

Comparison of Bipartite Versus Tripartite Osteotomy for Maxillary Transversal Expansion Using 3-Dimensional Preoperative and Postexpansion Computed Tomography Data

To evaluate tripartite paramedian versus bipartite median osteotomy in surgically assisted rapid maxillary expansion. Tripartite osteotomy was performed between the lateral incisors and canines at the former premaxillary junction to avoid midline diastema, septal and columellar dislocation, and asymmetric expansion, minimizing high-distraction forces through bilateral doubled osteotomy on periodontia and thus reducing vestibular attachment loss and producing stable callus formation to avoid relapse. The preoperative and postexpansion computed tomography data from 50 patients were analyzed in multiplanar viewing for bodily segment movement, vestibular bone loss, and transverse skeletal and dental widening with predefined landmarks. Of the 50 patients, 22 had undergone tripartite and 28 had undergone bipartite osteotomy. Using an independent t test, both osteotomies permitted adequate transverse skeletal expansion in the premolars, converging, however, in the molars. Bipartite osteotomy resulted in less symmetry in transverse skeletal widening, greater bodily segment movement in the first premolar/molar, and greater vestibular bone loss. Tripartite osteotomy resulted in greater overall expansion and less bone remodeling. On variance analysis, tripartite bone-borne distraction resulted in the greatest decrease of transverse expansion in patients older than 20 years. The tripartite osteotomy also provoked distractor- and age-independent outward segmental movement. Bipartite osteotomy resulted in distractor- and age-independent inward segmental movement. Bipartite osteotomy showed the greatest bone resorption in patients younger than 20 years old in the molars and tripartite osteotomy in patients older than 20 years in the premolars. Tripartite paramedian osteotomy allowed greater overall symmetric expansion compared with bipartite median osteotomy, with, however, a decline in transverse widening to the posterior. Bipartite osteotomy should be preferred whenever good periodontal status permits greater vestibular bone loss and a midline diastema and asymmetric expansion and a midline shift will be tolerated by the patient. Tripartite osteotomy should be chosen whenever a midline diastema and shift, septal and columellar dislocation, asymmetric expansion, and larger distraction forces on the paradontia, resulting in vestibular attachment loss, are to be avoided.

Comparison of Tooth- and Bone-Borne Devices in Surgically Assisted Rapid Maxillary Expansion by Three-Dimensional Computed Tomography Monitoring

Comparison of bone-borne (BB) versus tooth-borne (TB) distraction in surgically assisted rapid maxillary expansion, secondary variables were bipartite (2S) or tripartite (3S) osteotomy, pterygomaxillary osteotomy (+PP) or not (jPP), and age (920 years old [920] and G20 years old [G20]). Fifty patients received three-dimensional computed tomography examination preoperatively and after expansion; 24 had BB, and 26 had TB distraction. Predefined preoperative landmarks versus postexpansion positions were assessed in multiplanar viewing. Bone-borne devices had bigger overall skeletal and dental maxillary expansion declining from anterior to posterior, more asymmetric expansion, less vestibular bone resorption, and less dental tipping; TB devices showed similar dorsal decrease in transverse skeletal and dental maxillary expansion from anterior to posterior, more vestibular bone resorption, particularly in the premolars, and more dental tipping. Bone-borne 3S +PP G20 had the biggest decrease in transverse skeletal widening and biggest segmental outward inclination; BB 3S +PP 920 had the biggest decline in transverse dental widening; TB 2S YPP G20 had the biggest segmental inward inclination; BB 2S YPP 920 had the biggest dental tipping; BB 2S G20 had the biggest vestibular bone resorption in molars; and TB 3S 920 and BB YPP had the biggest vestibular bone resorption in premolars. There was a significant correlation between transverse widening and segmental inclination; that is, a bigger amount of transverse widening provokes less segmental inclination.

Elongation gastroplasty with transverse fundoplasty: The Jeyasingham repair

Surgical management of massive hernias and complex gastroesophageal reflux disease requires a tension-free repair with reliable reflux control. The aim of this observation was to evaluate the functional results of a modified Collis-Nissen gastroplasty with a transverse widening fundoplasty. Between 1995 and 2007, 26 patients underwent a 3-cm cut elongation gastroplasty with a transverse widening of the fundus followed by a 3-cm total (n = 24) or partial (n = 2) fundoplication. Indications for the operation were symptomatic massive hiatal hernias (n = 4), hiatal hernias with Barrett's esophagus (n = 8), or correction of previously failed antireflux fundoplications (n = 14). Barrett's esophagus was documented in 19 of the 26 patients. Pre- and postoperative assessment included symptoms, barium swallow, endoscopy, manometry, and 24-hour pH monitoring. There was no postoperative mortality. Complications were recorded in 6 patients. Median follow-up was 105 months. Reflux symptoms present in all patients before the operation were found in 5 patients postoperatively (P < .001). Radiologic assessment documented an intact fundoplication in all patients. Lower esophageal sphincter gradient increased from a mean of 7.5 to 15 mm Hg (P = .003). Acid exposure (17% preoperatively) decreased significantly to 1% postoperatively (P < .001). Endoscopically, mucosal damage quantification decreased (3.1 preoperatively to 1.5 postoperatively; P < .001). All mucosal breaks healed but the columnar-lined metaplasia persisted. This modified elongation gastroplasty provided a reliable repair for massive hernias, shortened Barrett's esophagus, and reoperations. The lower esophageal sphincter gradient was restored and remained stable. Reflux exposure was reduced, and acute mucosal damage disappeared. Columnar-lined metaplasia remained unchanged.

Transverse expansion of the maxilla using a multisegmentation technique

In a long-term prospective study multisegmentation for transverse widening of the maxilla was followed up to calculate tendency to relapse and clinical outcome. Thirty-six patients were followed up for 30 months and 13 for 60 months postoperatively. There were no complications after the maxillary operations. Transverse widening varied from 2 mm to 1.5 cm in the posterior part of the maxilla, and was posterior to the canine teeth by a multisegmentation technique in the palatal bone. Although there was a tendency to relapse, which varied from 0.3-0.8 mm in the series, the clinical results are highly satisfactory.

Phimosis. Preputial plasty using transversal widening on the dorsal side with EMLA local anesthetic cream

Background/Purpose In the United States, the treatment of choice for the correction of phimosis is circumcision, whereas in European countries, the condition is usually treated by preputial plasty using Duhamel's method or modified versions. We report our experience in correcting phimosis by preputial plasty using transversal widening on the dorsal side with EMLA local anesthetic cream. Methods Twenty-six patients with phimosis were operated on by preputial plasty, under local anesthesia with EMLA cream. A transversal incision is made on the dorsal side of the ring of prepuce, like 3 contiguous Ts, the middle one inverted with the long arm on the preputial mucosa side. The 2 small mucocutaneous flaps of the prepuce are separated and then sutured with interrupted stitches, thus transforming the incisions from T to V. Results No postoperative complications were observed. At 1-year follow-up, the cosmetic and functional results were satisfactory. Conclusions The technique of preputial plasty that the authors present enlarges the stenotic ring of prepuce by a transversal widening on the dorsal side. The ring of prepuce obtained is wide and symmetrical on its dorsal and ventral sides and therefore cosmetically and functionally satisfactory. It is a good alternative to the more radical circumcision technique.

Case report of simultaneously surgically assisted rapid palatal expansion and mandibular symphysis transverse widening

Case report of simultaneously surgically assisted rapid palatal expansion and mandibular symphysis transverse widening

Palatal distractor. An innovative approach for palatal expansion

A method is introduced using a newly developed palatal distractor, which allows rapid transversal widening in cases of maxillary compression. After osteotomy of the palate parallel to the sutura palatina mediana as well as to the lateral walls of the maxillary sinuses, the applied distractor permitted a transversal widening of 7.5 mm within 3 weeks. During the 3-month period of retention, multibanded orthodontic therapy could be performed. Because of the short treatment period, absence of recurrence, and easy handling for the patient this method is recommended for clinical use.

Transverse Development of the Human Jaws Between the Ages of 8.5 and 15.5 Years, Studied Longitudinally With Use of Implants

We report longitudinal data on the transverse widening of the maxilla and mandible from a sample of normal subjects (11 males and 20 females) with metallic implants of the Bjork type. Data were from measurements on lateral and frontal (posterior-anterior) cephalograms generated at annual intervals between the ages of 8.5 and 15.5 years (although data were not available for all subjects at all time points). The maxillary data were, in general, similar to those reported by Bjork and Skieller (1974, 1977) for a smaller sample of slightly younger boys. During the age interval studied, transverse widening was greater in the more posterior part of the palate. [The mean annual rate of change in the posterior-most (zygomatic) region was 0.43 mm, sd = 0.18 mm; p less than 0.001.] Although the rate of palatal widening was not large in absolute terms, widening appeared to continue throughout the age interval under study, and there was no evidence to support the conventionally accepted idea that palatal growth in the transverse dimension tapers off substantially or even ceases during the age interval under observation. Evidence of statistically significant widening of the mandibular arch by means of transverse rotation of the osseous matrix was noted in nine of the 29 subjects for whom three-dimensional mandibular information was available. For these nine subjects, the estimated annual increase in mandibular arch angle ranged from 0.52 degrees to 1.40 degrees. As far as we are aware, this is the first report of mandibular matrix rotation in the transverse direction from a sample of subjects with metallic implants. The finding that spontaneous changes in this dimension are relatively common raises the possibility that classical attitudes concerning the immutability of osseous relationships in the symphyseal region during growth may be inappropriate.