Arch Expansion Research Articles

CBCT Assessment of Dental and Skeletal Changes Using the Damon versus Conventional (MBT) System

Introduction: The primary aim of this pilot study was to compare cases treated with the Damon System and a Conventional Mechanics system utilizing Cone Beam Computed Tomography (CBCT) in the evaluation of changes in dental and skeletal arch width and length. The secondary purpose was to evaluate differences between the three CBCT views (3-D coordinate, sectional, and volume views). Methods: Eleven patients (≥ 18 years of age; measured total of 40 maxillary antimeres and 44 mandibular antimeres) with moderate to severe crowding who had both pre and post-treatment CBCTs and were treated nonextraction, either with conventional edgewise or self-ligating Damon appliances were retrospectively selected from two orthodontic practices. The arch length, inter-occlusal, inter-apical, inter-buccal and inter-lingual alveolar crest arch widths and the bucco-lingual angulation for canine, premolars and first molars were measured. Different CBCT views were evaluated by first measuring the inter-occlusal distances of the respective teeth in the coronal section and the volume views. These measurements were compared with those gathered previously using the 3-D coordinate system. A paired t-test, an independent t-test, and an ANOVA were used for statistical analysis. Results: Both non-extraction treatment modalities resulted in inter-occlusal arch width expansion in both the maxilla and mandible. The overall expansion of arches in the Damon treated cases was statistically greater than in the Conventional cases. Maxillary and mandibular arch lengths were increased, but not significantly in both groups. There were no statistically significant differences between the three CBCT views. Conclusions: Both the Damon and the Conventional systems resulted in increased arch width and length, but the Damon system caused significantly more overall arch expansion. There was less tipping of the teeth during arch expansion in the Conventional system. The ratio of crown to root movement in the Conventional system versus the Damon system in the maxilla was approximately 1:1 versus 3:1, and in the mandible 3.6:1 versus 6:1, respectively.

Biomechanical role of the transverse carpal ligament in carpal tunnel compliance.

The transverse carpal ligament (TCL) is a significant constituent of the wrist structure and forms the volar boundary of the carpal tunnel. It serves biomechanical and physiological functions, acting as a pulley for the flexor tendons, anchoring the thenar and hypothenar muscles, stabilizing the bony structure, and providing wrist proprioception. This article mainly describes and reviews our recent studies regarding the biomechanical role of the TCL in the compliant characteristics of the carpal tunnel. First, force applied to the TCL from within the carpal tunnel increased arch height and area due to arch width narrowing from the migration of the bony insertion sites of the TCL. The experimental findings were accounted for by a geometric model that elucidated the relationships among arch width, height, and area. Second, carpal arch deformation showed that the carpal tunnel was more flexible at the proximal level than at the distal level and was more compliant in the inward direction than in the outward direction. The hamate-capitate joint had larger angular rotations than the capitate-trapezoid and trapezoid-trapezium joints for their contributions to changes of the carpal arch width. Lastly, pressure application inside the intact and released carpal tunnels led to increased carpal tunnel cross-sectional areas, which were mainly attributable to the expansion of the carpal arch formed by the TCL. Transection of the TCL led to an increase of carpal arch compliance that was nine times greater than that of the intact carpal tunnel. The carpal tunnel, while regarded as a stabile structure, demonstrates compliant properties that help to accommodate biomechanical and physiological variants such as changes in carpal tunnel pressure.

CORTICOTOMY-PERIODONTALLY ACCELERATED OSTEOGENIC ORTHODONTICS - A SURGICAL TECHNIQUE AND CASE REPORT

AbstractCorticotomy-assisted orthodontic treatment involves selective alveolar decortication in the form of decortication lines and dots performed around the teeth that are to be moved. It is done to induce a state of increased tissue turnover and a transient osteopenia, which is followed by a faster rate of orthodontic tooth movement.This technique has several advantages, including faster tooth movement, shorter treatment time, safer expansion of constricted arches, enhanced post-orthodontic treatment stability and extended envelope of tooth movement.This case report describes a surgical technique and case report involving periodontally accelerated osteogenic orthodontics.

Immediate effects of rapid maxillary expansion on the naso-maxillary facial soft tissue using 3D stereophotogrammetry

BackgroundRapid maxillary expansion (RME) is used to expand the narrow maxilla. Dental and skeletal affects have previously been reported but few studies have reported on the overlying soft tissue changes. This study reports on the immediate effects of RME on the naso-maxillary facial soft tissue using 3D stereophotogrammetry. MethodsFourteen patients requiring upper arch expansion using RME as part of their full comprehensive orthodontic plan were recruited. Cone beam CT scans and stereophotogrammetry images were taken for each patient; pre-RME activation (T0) and immediately post-RME expansion (T1). Based on twenty-three landmarks, 13 linear and 3 angular measurements were made from each of the stereophotogrammetry images. A linear measurement at ANS was taken from each CBCT image. Using a Wilcoxon signed rank test, the pre-RME and post-RME measurements were compared. ResultsThe mean separation of the anterior nasal spine was 3.8 mm ± 1.2 mm. The largest median increase was in nasal base width (1.6 mm), which was statistically significant (p = 0.001). Changes in the nasal dorsum height, nasal tip protrusion, philtrum width, and upper lip length were not statistically significant (p < 0.05). No significant differences were observed in the nostril linear measurements, expect for columella width (p = 0.009). Naso-labial angle decreased but was not statistically significant (p = 0.276). The only statically significant angular change was an increase in the nasal tip displacement angle (p = 0.001). ConclusionRapid maxillary expansion produces subtle changes in the naso-maxillary soft tissue complex. There is an increase in nasal base width, retraction and flattening of the nasal tip. These changes are small, less than 2 mm and variable between patients.

Maxillay canine impaction: Early diagnosis &amp;amp; Preventive approaches

Maxillary canine is the most common impacted tooth except third molars. In Asian populations, labial impaction is more common than palatal impaction, but palatal impaction is three times more common than labial impaction in Caucasion. The incidence of maxillary canine impaction is known as 1~3%, and 12% of these cases are involved in the root resorption of the adjacent lateral incisor. In children, early diagnosis is important to prevent the impaction of maxillary canine through clinical and radiographic examinations. In addition, preventive measures should be considered at the proper time. These measures include the removal of deciduous canines and the expansion of the maxillary arch.

A clinical comparison of maxillary expansion: TransForce transverse appliance versus NiTi palatal expander

BackgroundTransForce lingual appliances are a new series of expansion appliances introduced to develop arch form in a more physiologic manner. The aim of the present study was to evaluate and compare the effects of the TransForce transverse appliance (TTA) and the nickel-titanium palatal expander (NPE) on arch development. MethodsTwenty patients (mean age 11.8 years) with skeletal class II malocclusion requiring arch expansion as a part of orthodontic treatment were enrolled. Patients were randomly divided into two groups of 10 each. Study models and lateral cephalograms were obtained from the patients at the beginning of the treatment (T1) and at the end of expansion (T2). Transverse interdental width, skeletal expansion, alveolar tipping, molar rotation, ratio of intercanine to intermolar change, and rate of expansion were analyzed by using study models. ResultsBoth appliances produced significant changes in transverse arch dimensions. Rate of expansion with NPE was significantly greater (P = 0.03). Intergroup comparisons of skeletal expansion, alveolar tipping, molar rotation, and the ratio of intercanine to intermolar change showed no significant differences. ConclusionsBoth appliances were efficient for expanding the maxillary dentition and alveolar process. Both appliances have potential for skeletal expansion. Rate of expansion with the NPE was greater than that with the TTA.

English

It is well known that most of the orthodontic treatments require more time for completion of the treatment. This technique literally accelerates the orthodontic corrections. Periodontally - assisted orthodontic treatment is an established and efficient orthodontic technique that has recently been studied in a number of publications. It has gradually gained popularity as an adjunct treatment option for the orthodontic treatment of adults. It involves selective alveolar decortication in the form of decortication lines and dots performed around the teeth that are to be moved. It is done to induce a state of increased tissue turnover and a transient osteopenia, which is followed by a faster rate of orthodontic tooth movement. Orthodontic treatment time with this technique will be reduced to one-third the time of conventional orthodontics. This technique has several advantages, including faster tooth movement, shorter treatment time, and safer expansion of constricted arches, enhanced post-orthodontic treatment stability and extended envelope of tooth movement. The aim of this article is to present a comprehensive review of the literature, including historical background, contemporary clinical techniques, indications, contraindications, complications and side effects.

Fallibility of Pont's index in a Bangladeshi population

PurposeNumerous indices have been proposed to help the clinician decide how much maxillary expansion will be required to alleviate crowding. The aim of this study is to test the fallibility of Pont's index in a Bangladeshi population, by assessing the applicability of this index in a Bangladeshi population and to compare the results with inter gender, inter normal occlusion, class I malocclusion, class II and class III malocclusion. Materials and methodsDental casts of 220 Bangladeshi individuals, comprising 95 males and 125 females (age range, 18–24 years, mean age=20). The records belonged to 100 subjects with normal occlusion. Sixty subject with class I malocclusion, including those who showed crowding more than 5mm and 30 subjects each with class II and class III malocclusion. Arch widths were compared between the measured and the predicted values derived from Pont's formula. Comparative statistics were applied. ResultsNo significant differences were detected between inter gender and inter normal occlusion and malocclusions. The average predicted inter-premolar width (39.18±2.13mm) and inter-molar widths (48.97±2.65mm) were higher than the actual measured means. The premolar index (85.82) and molar index (66.93) of the Bangladeshi were higher than the original Pont's indices. ConclusionSignificant correlations were noted for inter-premolar and inter-molar width. The findings suggest that Pont's index potentially overestimate the arch expansion required to alleviate crowding.

Rapid Maxillary Expansion for Obstructive Sleep Apnea: A Lemon for Lemonade?

Rapid Maxillary Expansion for Obstructive Sleep Apnea: A Lemon for Lemonade?

The effect of incremental lower lip advancement on oral pressure and EMG activity of the lower lip

During orthodontic arch expansion, the teeth are displaced against the perioral soft tissues. This can affect the equilibrium of forces that are thought to act on teeth, with consequent implications for long-term stability. The aim of this study was to investigate the effect of incremental lower lip advancement on intraoral pressure and electromyographic (EMG) activity of the lower lip. Intraoral pressure and EMG activity was measured in 10 participants (2 males, 8 females; 22 years ± 7 months) as the lower lip was incrementally advanced using three custom-made vacuum-formed stents of differing labial thicknesses (0.5, 2.5, and 4.5 mm). A task paradigm including at rest recordings and maximal voluntary contraction was completed for each tray. Resting lip pressure generated increased as the lower lip was advanced (P < 0.001). The EMG activity of the lower lip increased significantly (P < 0.001) only once the lip was advanced from 2.5 to 4.5 mm. For the pressure recordings, the response to incremental lip advancement showed considerable individual variation. These findings suggest that the initial pressure increase on the lower incisors was mostly likely due to the inherent viscoelastic properties of the lower lip, while the pressure increase between the 2.5 and 4.5 mm advancement was due to increased muscle activity. Each individual also responded to lower lip advancement in a different yet subject-specific manner.

Long-term stability of dentoalveolar, skeletal, and soft tissue changes after non-extraction treatment with a self-ligating system.

ObjectiveTo evaluate the long-term effects of self-ligating brackets (SLBs) on transverse dimensions of arches and skeletal and soft tissues and to quantitatively evaluate the treatment outcome after non-extraction treatment with SLBs.MethodsThe sample consisted of 24 (18 female and six male) subjects, with a mean age of 14.23 ± 2.19 years, who received treatment with the Damon®3 appliances. Complete records including cephalometric radiographs and plaster models were obtained before treatment (T1), immediately after treatment (T2), six months after treatment (T3), and two years (T4) after treatment. Digital study models were generated. Twenty lateral cephalometric, six frontal cephalometric, and eight dental cast measurements were examined. The Peer Assessment Rating index was used to measure the treatment outcome. The Wilcoxon test was applied for statistical analysis of the changes.ResultsThere were significant increases in all transverse dental cast measurements with active treatment. There was some significant relapse in the long term, particularly in maxillary width (p < 0.05). Statistically significant increases were found in nasal (p < 0.001), maxillary base, upper molar, lower intercanine, and antigonial (p < 0.05) widths in T1-T2. Lower incisors were proclined and protruded in T1-T2.ConclusionsSLBs correct crowding by mechanisms involving incisor proclination and protrusion and expansion of the dental arches, without induction of clinically significant changes in hard and soft tissues of the face.

Are self-ligating brackets an advantageous alternative for non-extraction treatments?

The objective of this nonsystematic review of the literature is to determine whether or not self-ligating brackets are an equally effective alternative to traditional brackets for non-extraction treatments. The agreed upon criteria are indications for extractions, the biomechanical approach, the stability of the treatment results, the iatrogenic effects and the ergonomics.The studies discuss arch expansion with the use of self-ligating brackets. One study mentions a lack of control of osseous management including tipping and buccal bone thickness in the lateral sectors. The mandibular incisor inclination that was obtained does not appear to be correlated to the type of bracket but rather to initial factors specific to the patient. We didn’t find any study dealing with the long-term stability of the results.Regarding patients, self-ligating brackets do not reduce the pain, the number of extractions, the incidence of resorption or the risk for caries. Self-ligating brackets shortened the clinical time for an experienced practitioner but not the length of the time of comprehensive treatment and alignment. Some studies report an increase in cases of emergency. Finally, these brackets are more difficult to position.

Space supervision and guidance of eruption in management of lower transitional crowding: A non-extraction approach

Mandibular incisor crowding in the mixed dentition is one of the most common problems presenting to the orthodontist. Asymmetry of alignment, premature loss of primary canine(s), and disruption in arch integrity are all early benchmarks of a tooth size/arch length discrepancy in the transitional dentition that can occur independent of any skeletal discrepancy. Space supervision and guidance of eruption refer to treatment interventions during the early to mid-mixed dentition periods that influence the eruption patterns and positioning of the permanent teeth during their transition. Generally considered applicable to individuals with adequate overall arch dimensions to accommodate a normal complement of permanent teeth with an acceptable esthetic and functioning occlusion, guidance of eruption involves the implementation of directed interventions to optimize the eruption and alignment patterns of the permanent teeth as part of a non-extraction protocol.

The rational method of orthodontic treatment in rural school children

Aim. To analyze the effect of orthodontic devices in treating malocclusion in rural schoolchildren. Methods. The first group consisted of 25 schoolchildren aged 9-10 years with malocclusions treated with Frankel functional regulator, the second group consisted of 25 schoolchildren of the comparable age treated with function generating bite. Treatment results were assessed after 12 months of treatment in both groups. The treatment success was defined by calculation of the Pont’s and Korkhaus indices of dental arch dimensions. An adaptation to orthodontic devices was controlled monthly. Results. Schoolchildren treated with Frankel functional regulator abandoned treatment in 24% of cases (6 out of 25 cases), while treated with function generating bite - in 8% of cases (2 out of 25 cases). Dental arch expansion was registered in both groups. In patients treated with Frankel functional regulator the dental arch expansion reached 2.4-3 mm (mean value 2.7±0.3 mm), with function generating bite - 2.8-3.2 mm (mean value 3.0±0.2 mm). Conclusion. Function generating bite was the most rational malocclusion treatment in rural schoolchildren, its use was associated with lesser number of dropouts due to discomfort and allowed to achieve better results.

Non-surgical, non-extractive treatment of a severe class III malocclusion in permanent dentition: Follow-up of a case 24years posttreatment

This case shows a patient who had presented a severe Class III malocclusion, both maxillary and mandibular crowding and an impacted canine: she is now 24 years posttreatment. She was treated, in permanent dentition, by proclination of both maxillary and mandibular incisors, expansion of the maxillary arch and of the mandibular intercanine width and disinclusion of the impacted canine. At debonding, she presented well-aligned arch forms, a centered midline and a pleasant smile. Twenty-four years after treatment, her records show that the occlusion has remained stable. The use of wires of almost full thickness helped effectively control incisor torque, thus keeping the teeth inside the cortical bone and limiting the expected periodontal problems.

The effectiveness of non-surgical maxillary expansion: a meta-analysis

To evaluate and compare the effectiveness of rapid maxillary expansion (RME) and slow maxillary expansion (SME). PubMed, Embase, Web of Science, CENTRAL, ProQuest Dissertations & Theses, ClinicalTrial.gov, and SIGLE were searched from January 1980 to October 2012 for randomized or non-randomized controlled trials. The processes of study search, selection, and quality assessment were conducted independently and in duplicate. Original outcome data underwent statistical pooling through Review Manager 5. Fourteen eligible studies were finally included and two interventions (RME and SME) studied. Four outcomes (maxillary intermolar width, maxillary intercanine width, maxillary interpremolar width, and mandibular intermolar width) during three time periods (expansion, retention, and net change) were statistically pooled. The sensitivity analysis revealed that the results from the meta-analysis were generally robust. Egger's test and Begg's test detected no publication bias except for maxillary intercanine width in expansion period for SME versus control. SME is effective in expanding maxillary arch, while we cannot determine its effectiveness in mandibular arch expansion. RME is effective in expanding both maxillary and mandibular arches. Furthermore, SME is superior to RME in expanding molar region of maxillary arch, while similar with RME in mandibular arch expansion. However, we cannot compare their effectiveness in maxillary anterior region.

Change of arch dimension using two different expansion modalities in adults-MARPE and continuous archwire: a pilot study

Considering the high prevalence, transverse control in adult patients presenting relatively narrow maxillary width is a challenging issue. This study compared the pattern of arch expansion induced by either miniscrew-assisted rapid palatal expander (MARPE) or continuous archwire engaged on self-ligating brackets. Age-matched adults groups(N=15 each) were treated with respective appliance. In both groups, all intercanine, interpremolar, and intermolar widths increased, and significantly greater change was noted in the intermolar region. Buccal tipping was minimal in both groups. Subsequent arch length increase, lingual tipping of incisors and distal tipping of molars were also found in both groups. According to the results, it can be concluded that the MARPE induced generally more arch expansion, particularly in the intermolar width, indicating that the adults showing buccal crossbite of the molars may have to undergo expansion via MARPE prior to arch alignment using continuous archwire.

Dissecting aortic aneurysm in a 23 year-old hypertensive woman

A 23 year-old woman was admitted to our hospital after loss of consciousness with chest pain in a stress situation (the woman’s wedding ceremony). The patient had been irregularly treated for mild hypertension from the age of eight. Secondary causes of hypertension were never diagnosed. There were no morphological features of Marfan syndrome in the patient. She had been operated upon for vesicoureteral reflux in childhood. The patient was admitted in a stable condition. Her physical examination revealed diastolic aortic murmur and tachycardia, blood pressure was normal. Transthoracic echocardiography showed expansion of ascending aorta to 43 mm and thoracic aorta dissection (Fig. 1). Chest computed tomography demonstrated thoracic aorta dissection, which began 15 mm above the aortic valve, expansion of ascending aorta to 44 mm, expansion of arch of aorta to 28 mm and pseudocanal of the descending aorta to 6.5 mm (Fig. 2). The dissection included brachiocephalic trunk, both common carotid arteries, left subclavian artery and abdominal aorta to the celiac trunk (Fig. 3). The patient was operated upon immediately. A dissecting aneurysm DeBakey I type was diagnosed intraoperatively. The Bentall de Bono procedure was done with implantation CompositGraft St. Jude Medical 25. The early postoperative period was complicated by bleeding, requiring rethoracotomy and low output syndrome. Because of this, the patient was treated with pressor amines. In the following days, postoperative acute kidney failure occurred and patient was subjected to dialysis. Tamponade occurred and a puncture was performed with evacuation of liquid. The antihypertensive treatment was modified and vitamin K antagonist therapy was initiated. The patient was discharged from hospital on the 26th day of treatment. Aortal dissection is one of the most life-threatening complications of hypertension. The commonest causes of aortal dissection are arterial wall abnormalities, which had not been demonstrated in histopathology in our patient. Long term, inadequately treated hypertension was the only aetiology factor of aortic dissection in this young woman.

Characteristics of dentoskeletal morphology and treatment changes in 2-maxillary premolar extraction: A comparison with 4-premolar extraction

BackgroundThe present study aimed to clarify the characteristics of dentoskeletal morphology and treatment changes after 2-maxillary premolar extractions to treat Class II malocclusion, by comparing pre- and post-treatment lateral cephalograms and dental casts from cases with 4-premolar extractions. MethodsSubjects comprised patients who had undergone orthodontic treatment for Class II molar relationship using either maxillary first premolar extraction (U2 group, n = 27) or maxillary and mandibular first premolar extraction (UL4 group, n = 27). Pretreatment (T1) and post-treatment (T2) lateral cephalograms and dental casts were examined. Groups were compared for differences at T1 and T2, and in T2–T1 change using unpaired t tests. Among the analysis items showing significant differences at T1, those that could discriminate between groups U2 and UL4 at T1 were extracted by stepwise logistic regression analysis. ResultsDentoskeletal morphology in the U2 group exhibited a severe Class II molar relationship, little need for maxillary incisor retraction, and a morphology in which bite opening was severe. Treatment changes in the U2 group showed that extraction spaces were used for mesial movement of maxillary molars in many cases, that bite-opening resulted from mandibular clockwise rotation, and that contraction of the upper arch and expansion of the lower arch occurred in anteroposterior and lateral directions. Severity of Class II molar relationship, anteroposterior position of mandibular incisors, and lower arch depth were selected as criteria for distinguishing pretreatment between groups U2 and UL4. ConclusionCases with 2-maxillary premolar extraction showed a characteristic dentoskeletal morphology compared to cases with 4-premolar extraction.

The Trikki lingual appliance

Lower anterior crowding is a frequent finding in early mixed dentition. Left untreated, it may lead to extractions of permanent teeth or even to impactions. The Trikki lingual appliance is a fixed device that aids in lower arch expansion and space gaining, especially in the lower anterior region, without the need for brackets. Patients with a deep-bite tendency, retroclined lower incisors, and/or lower anterior crowding are good candidates. The Trikki appliance may be used to shift the lower midline in cases of premature unilateral loss of a primary canine or to gain space and align ectopically erupted lower incisors. It requires no patient compliance, is effective, is easy for the clinician to adjust, and can be incorporated into any early treatment protocol.