Effect of anodization on friction behavior of ß­titanium orthodontic archwires.

PURPOSE: To evaluate the effects of anodization on the friction behavior of beta-titanium (ß-Ti) orthodontic archwires in conventional or self-ligating brackets in vitro. METHODS: ß­Ti archwires (0.018â€¯× 0.025 inch) pre- and postanodization were tested in combination with 0.022-inch stainless steel conventional and self-ligating brackets. The surface composition and oxide thickness of the ß­Ti archwires pre- and postanodization were measured using Auger electron spectroscopy (AES) and transmission electron microscopy (TEM). Detailed surface topography and roughness were assessed using atomic force microscopy (AFM). Surface topographies of the ß­Ti archwires pre- and postanodization were examined using scanning electron microscopy (SEM). Friction was measured using a universal testing machine; the data were statistically analyzed. RESULTS: Postanodization, the identified titanium oxide layer on the surface of the ß­Ti archwires increased in thickness from 10 to 100 nm; at the same time, the values for surface roughness were significantly reduced by half (p < 0.001). The archwire surfaces post anodization were harder and had fewer scratches after the friction test. Anodization significantly reduced 23.77% of the static (p < 0.01) and 25.61% of the kinetic (p < 0.001) friction of the ß­Ti archwires in conventional brackets, while it significantly reduced 85.71% of the static and 84.38% of the kinetic friction (p < 0.01) in self-ligating brackets. CONCLUSION: Anodization reduced the ß­Ti archwire friction, which was particularly more effective in combination with self-ligating brackets. The friction reduction via anodization could be attributed to the increased thickness, surface hardness, and decreased surface roughness of the titanium oxide layer.

Comparison between microporous and nanoporous orthodontic miniscrews : An experimental study in rabbits.

PURPOSE: Surface characteristics of orthodontic miniscrews might affect survival rates and removal torque values (RTVs). This experimental study aimed to clarify whether and why a microporous or nanoporous surface promotes higher survival rates and RTVs for orthodontic miniscrews. METHODS: Using a split-leg design, one set each of nonporous (sham control, n = 24) and microporous (control, n = 6), and three sets of nanoporous (experimental, n = 6 per set) miniscrews were implanted in the tibias of 12 New Zealand rabbits and immediately loaded with 1.5 N nickel-titanium coil springs for 12 weeks. The surface morphology, micropores, and nanotube diameters of the miniscrews were examined using scanning electron microscopy and field-emission scanning electron microscopy. The surface composition and thickness were determined using Auger electron spectroscopy. The survival rates and RTVs of each set were assessed. RESULTS: The nanoporous miniscrews had higher survival rates, RTVs (p < 0.001), and thicker nanotube oxide thicknesses (p < 0.001) than the nonporous and microporous miniscrews. The nonporous and microporous miniscrews had no nanotube structures. The surface oxide composition was titanium dioxide (TiO2). The threshold RTV, TiO2 thickness, and nanotube diameter of nanoporous miniscrews needed to promote the experimental survival rate to 100% was determined to be 6.6 ± 0.8 N-cm (p < 0.05), 22.5 ± 4.8 nm (p < 0.05), and 17.6 ± 2.3 nm or above, respectively. CONCLUSION: Nanoporous surfaces promoted higher survival rates and RTVs than microporous miniscrews. This could be due to TiO2 nanotube structures with thicker oxide layers in nanoporous miniscrews.

Esthetic Interdisciplinary Treatment: An Effective Approach to Address Complex Short-Face Adult Cases.

Traditional interdisciplinary treatment (IDT) for simultaneous correction of complex facial, smile, and dental problems in a so-called "shortface" adult patient can be extremely challenging. Such treatment typically has been based mainly on dental diagnosis with little or no consideration given to the proper correspondence of teeth position to the patient's jaws so as to enhance overall esthetics. Modern esthetic interdisciplinary treatment (E-IDT), however, is an overall esthetics-driven treatment planning approach based on a global diagnosis rather than primarily a dental diagnosis, while still considering the patient's health and function. This article, which features a clinical report, describes treatment of a woman with a short, square face who originally was contemplating cosmetic surgery for correction of her facial features. Instead, a nonsurgical E-IDT approach was taken to successfully and wholly resolve her multifaceted disorders. The article reviews conventional treatment options for short-face adult patients and explains modern E-IDT, which may involve a combination of orthodontic therapy, implant treatment, periodontal treatment, and prosthodontic correction.

The immediate effect of alternate rapid maxillary expansions and constrictions on the alveolus: a retrospective cone beam computed tomography study.

BACKGROUND: Rapid maxillary expansion reduced the expander's anchor teeth buccal alveolar bone thickness. However, the effects of alternate rapid maxillary expansions and constrictions (Alt-RAMEC) on the expander's anchor teeth alveolar thickness has not been assessed. The purpose of this retrospective study was to evaluate the effects of Alt-RAMEC on the alveolus surrounding the anchor teeth of a double-hinged expander. METHODS: Twenty-six individuals, including 12 males (11.5 ± 1.00 years) and 14 females (11.5 ± 0.90 years), who had double-hinged expander for 7 weeks of Alt-RAMEC and then 3 months of maxillary protraction, were included. Their cone beam computed tomography (CBCT) images taken 3-6 months before treatment (T0) and after 7 week of Alt-RAMEC (T1), were studied for the buccal alveolar bone thickness (BABT) and palatal alveolar bone thickness (PABT) of the expander's anchor teeth (first molars and first and second premolars) in four axial sections. The intra-class correlation coefficient, Dahlberg's formula, and paired t tests were used to analyze the method errors, and the intra-group changes of the BABT and PABT at T0-T1 were analyzed by paired t test (p < 0.05). RESULTS: The 7 weeks of Alt-RAMEC significantly reduced the BABT of the expander's anterior anchor teeth (0.54~ 70 mm, p < 0.05) and at the cervical region (0.14~ 0.25 mm, p < 0.05), but not at the apical region of the expander's posterior anchor teeth. The reduction of BABT by 7 weeks of Alt-RAMEC was within the scope of the initial BABT. On the opposite, the Alt-RAMEC significantly (p < 0.05) increased the PABT in the anterior anchor teeth and the cervical region of posterior anchor teeth. CONCLUSIONS: A 7-week protocol of Alt-RAMEC with double-hinged expander for maxillary protraction might reduce the buccal alveolar bone thickness of the expander's anchor teeth, although the reduction is within the scope of initial alveolar thickness of the expander's anchor teeth.

Effect of Butyrate on Collagen Expression, Cell Viability, Cell Cycle Progression and Related Proteins Expression of MG-63 Osteoblastic Cells.

AIMS: Butyric acid is one major metabolic product generated by anaerobic Gram-negative bacteria of periodontal and root canal infection. Butyric acid affects the activity of periodontal cells such as osteoblasts. The purposes of this study were to investigate the effects of butyrate on MG-63 osteoblasts. METHODS: MG-63 cells were exposed to butyrate and cell viability was estimated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The mRNA and protein expression of type I collagen and cell cycle-related proteins were measured by reverse-transcriptase polymerase chain reaction (RT-PCR), western blotting or immunofluorescent staining. Cellular production of reactive oxygen species (ROS) was analyzed by 2',7'-dichlorofluorescein (DCF) fluorescence flow cytometry. RESULTS: Exposure to butyrate suppressed cell proliferation, and induced G2/M (8 and 16 mM) cell cycle arrest of MG-63 cells. Some cell apoptosis was noted. The mRNA expression of cdc2 and cyclin-B1 decreased after exposure to butyrate. The protein expression of type I collagen, cdc2 and cyclin B1 were decreased, whereas the expression of p21, p27 and p57 was stimulated. Under the treatment of butyrate, ROS production in MG-63 cells markedly increased. CONCLUSIONS: The secretion of butyric acid by periodontal and root canal microorganisms may inhibit bone cell growth and matrix turnover. This is possibly due to induction of cell cycle arrest and ROS generation and inhibition of collagen expression. These results suggest the involvement of butyric acid in the pathogenesis of periodontal and periapical tissue destruction by impairing bone healing responses.

7-Ketocholesterol induces ATM/ATR, Chk1/Chk2, PI3K/Akt signalings, cytotoxicity and IL-8 production in endothelial cells.

Cardiovascular diseases (atherosclerosis, stroke, myocardiac infarction etc.) are the major systemic diseases of elder peoples in the world. This is possibly due to increased levels of oxidized low-density lipoproteins (oxLDLs) such as 7-ketocholesterol (7-KC) and lysophosphatidylcholine (LPC) that damage vascular endothelial cells, induce inflammatory responses, to elevate the risk of cardiovascular diseases, Alzheimer's disease, and age-related macular degeneration. However the toxic effects of 7-KC on endothelial cells are not known. In this study, 7-KC showed cytotoxicity to endothelial cells at concentrations higher than 10 µg/ml. 7-KC stimulated ATM/Chk2, ATR-Chk1 and p53 signaling pathways in endothelial cells. 7-KC also induced G0/G1 cell cycle arrest and apoptosis with an inhibition of Cyclin dependent kinase 1 (Cdk1) and cyclin B1 expression. Secretion and expression of IL-8 in endothelial cells were stimulated by 7-KC. 7-KC further induced intracellular ROS production as shown by increase in DCF fluorescence and Akt phosphorylation. LY294002 attenuated the 7-KC-induced apoptosis and IL-8 mRNA expression of endothelial cells. These results indicate that oxLDLs such as 7-KC may contribute to the pathogenesis of atherosclerosis, thrombosis and cardiovascular diseases by induction of endothelial damage, apoptosis and inflammatory responses. These events are associated with ROS production, activation of ATM/Chk2, ATR/Chk1, p53 and PI3K/Akt signaling pathways.

Simultaneous maxillo-mandibular distraction in early adolescence as a single treatment modality for durable correction of type II unilateral hemifacial microsomia: Follow-up till completion of growth.

BACKGROUND: Timing of surgical intervention in hemifacial microsomia (HFM) is controversial. Although mandibular osteodistraction in childhood for HFM is popular, recent data for single-stage distraction in growing HFM patients demonstrated long-term relapse. Literature suggests that adolescents in the late mixed dentition age or permanent dentition age (11-16-year-old) had more stable outcomes post-distraction than younger children. We present favorable experience using single-treatment simultaneous maxillo-mandibular distraction in early adolescent Pruzansky-Kaban type II HFM patients. METHODS: This was a retrospective longitudinal study of seven consecutive type IIa/b HFM growing patients (12-16-year-old) treated with simultaneous maxillo-mandibular distraction. Oral commissure cant was photographically measured preoperatively and at 6 months and annually ranging 3-7 years post-distraction. Ramus height and chin deviation were measured from radiographs done preoperatively and at distractor-removal, 1 year, 2 years, and 4 years post-distraction. RESULTS: Average age at osteodistraction and at latest follow-up was 13.7 and 18.6 years, respectively. Improvement was significant (p < 0.05) and sustained for mean oral commissure cant (5.1°-0.41°), mean ramus height ratio (0.59-0.86), and average chin deviation (15.9 mm-1.2 mm). Two subjects had mandibular branch palsy and one had mild pin-tract infection - all resolved. All were satisfied with their facial appearance. CONCLUSION: We have demonstrated good lasting outcomes at completion of growth with single-stage simultaneous maxillo-mandibular distraction for type II HFM adolescents in the late mixed-dentition or older age, and advocate this as an alternative to osteodistraction or orthognathic surgery upon skeletal maturity.

A modified presurgical orthopedic (nasoalveolar molding) device in the treatment of unilateral cleft lip and palate.

Nasoalveolar molding (NAM) can be done effectively to reshape the nasal cartilage and mold the maxillary dentoalveolar arch before surgical cleft lip repair and primary rhinoplasty. Presurgical NAM helps as an adjunct procedure to enhance the esthetic and functional outcome of the surgical procedures. We have developed a modified NAM device to suit to the needs of the patients coming from distant places for the treatment. This device helps in reducing the number of frequent visits the patient needs to take to the craniofacial center. The purpose of this presentation is to report this treatment technique and discuss its application.

Major Adverse Cardiovascular Events in Treated Periodontitis: A Population-Based Follow-Up Study from Taiwan.

BACKGROUND: The aim of the present study was to identify the long-term major adverse cardiovascular events (MACE) in treated periodontitis patients in Taiwan. METHODS: From the National Health Insurance Research Database (2001-2010), adult patients (≥ 18 years) with treated periodontitis were identified. Comparison was made between patients with mild form and severe form of treated periodontitis after propensity score matching. The primary end point was the incidence of MACE. RESULTS: A total of 32,504 adult patients with treated periodontitis were identified between 2001 and 2010. After propensity score matching, 27,146 patients were preserved for comparison, including 13,573 patients with mild form and 13,573 patients with severe form of treated periodontitis. During follow-up, 728 individuals in mild treated periodontitis group and 1,206 individuals in severe treated periodontitis group had at least 1 MACE event. After adjustment for gender, hyperlipidemia, hypertension and diabetes mellitus, severe treated periodontitis was associated with a mildly but significantly increased risk of MACE among older patients > 60 years of age (incidence rate ratio, 1.26; 95% confidence interval, 1.08-1.46). No association was found among younger patients ≤ 60 years of age. CONCLUSIONS: Severe form of treated periodontitis was associated with an increased risk of MACE among older Taiwanese patients, but not among younger Taiwanese patients. We should put more efforts on the improvement of periodontal health to prevent further MACE.

The effect of cleft maxillary distraction osteogenesis on the levator veli palatini and velopharyngeal function.

BACKGROUND: Le Fort I maxillary distraction with the rigid external distraction (RED) device is performed to correct severe midface retrusion in cleft patients, but it may adversely affect velopharyngeal function. OBJECTIVES: This study aims to investigate the angular changes in the levator veli palatini (LVP) and its influence on velopharyngeal function after maxillary distraction using 3-dimensional computed tomography (3D CT) scan volume rendered images. METHODS: This was a retrospective study of 12 patients. Group 1 had no velopharyngeal function deterioration and group 2 had velopharyngeal function deterioration. Preoperative and 1 year postoperative CT scans were analyzed with Mimics v10 software. Segmentation of the LVP and the nasopharyngeal airway was performed and volumetric images were obtained. Six measurements were made: (1) the angle between the levator plane and the Frankfort horizontal, (2) the angle between the levator plane and the soft palate plane, (3) the angle between the 2 LVP muscles, (4) the pharyngeal depth, and (5, 6) the movement of the inferior pharyngeal point with respect to the horizontal and vertical planes. The independent samples t test, Mann-Whitney test, and paired t tests were used for statistical analyses (P < 0.05). RESULTS: Group 2 had statistically significant reduction in the angle between the levator plane and Frankfort horizontal as well as the soft palate plane. Group 1 had a statistically significant increase in the pharyngeal depth and movement of the inferior pharyngeal point with respect to the horizontal plane. CONCLUSION: A decrease in the angle between the levator plane and the Frankfort horizontal or the soft palate plane was associated with velopharyngeal function deterioration.

Long-term comparison of the results of four techniques used for bilateral cleft nose repair: a single surgeon's experience.

BACKGROUND: The purpose of this study was to evaluate progressive changes in surgical techniques and results, aiming for improved nasal shape in primary bilateral cleft rhinoplasty. METHODS: This is an institutional review board-approved retrospective study. Ninety-one consecutive patients with bilateral complete cleft lip underwent primary cheiloplasty with four different techniques of nasal reconstruction from 1992 to 2007 as follows: group I, primary rhinoplasty alone; group II, nasoalveolar molding alone; group III, nasoalveolar molding plus primary rhinoplasty; group IV, nasoalveolar molding plus primary rhinoplasty with overcorrection; and group V, patients without cleft lip. The surgical results were analyzed using photographic records obtained at age 3 years. Four measurements and one angle measurement were obtained. A panel assessment was obtained to grade the appearance of the surgical results. RESULTS: The results are expressed in order from groups I through V. The nostril height-to-width ratio was 0.49, 0.59, 0.62, 0.78, and 0.82, respectively. The nasal tip height-to-nasal width ratio was 0.29, 0.39, 0.49, 0.57, and 0.60. The columella height-to-nasal width ratio was 0.11, 0.18, 0.22, 0.27, and 0.28. The dome-to-columella ratio was 1.88, 1.25, 1.26, 1.14, and 1.10. The nostril area ratio was 1.2, 1.17, 1.13, 1.11, and 1.07. The nasolabial angle was 144.95, 143.98, 121.98, 120.99, and 100.88. Finally, group IV had the best panel assessment. CONCLUSIONS: The results revealed that group IV had the best overall result. Presurgical nasoalveolar molding followed by primary rhinoplasty with overcorrection resulted in a nasal appearance that was closer to the patients without cleft lip.

Maxillary distraction osteogenesis in the adolescent cleft patient: three-dimensional computed tomography analysis of linear and volumetric changes over five years.

OBJECTIVE: To assess the results of maxillary distraction osteogenesis with the Rigid External Distraction System using three-dimensional computed tomography scan volume-rendered images with respect to stability and facial growth at three time frames: preoperative (T0), 1-year postoperative (T1), and 5-years postoperative (T2). DESIGN: Retrospective analysis. SETTING: Tertiary. PATIENTS: A total of 12 patients with severe cleft maxillary hypoplasia were treated between June 30, 1997, and July 15, 1998. The mean age at surgery was 11 years 1 month. INTERVENTIONS: Le Fort I maxillary distraction osteogenesis. Distraction was started 2 to 5 days postsurgery at a rate of 1 mm per day. The consolidation period was 3 months. No face mask was used. A paired t test was used for statistical analysis. MAIN OUTCOME MEASURES: Overjet, ANB, and SNA and maxillary, pterygoid, and mandibular volumes. RESULTS: From T0 to T1, there were statistically significant increments of overjet, ANB, and SNA and maxillary, pterygoid, and mandibular volumes. The T1 to T2 period demonstrated a reduction of overjet (30.07%) and ANB (54.42%). The maxilla showed a stable SNA and a small but statistically significant advancement of the ANS point. There was a significant increase in the mandibular volume. However, there was no significant change in the maxillary and pterygoid volumes. CONCLUSIONS: Maxillary distraction osteogenesis demonstrated linear and volumetric maxillary growth during the distraction phase without clinically significant continued growth thereafter. Overcorrection is required to take into account recurrence of midface retrusion over the long term.

Long-term comparison of four techniques for obtaining nasal symmetry in unilateral complete cleft lip patients: a single surgeon's experience.

BACKGROUND: This study was the result of a constant evaluation of surgical techniques and results to obtain excellence in primary cleft rhinoplasty. METHODS: This was a retrospective study from 1992 to 2003 comparing the long-term outcomes of four techniques of nasal reconstruction. There were 76 patients divided into four groups: group I (n = 23 patients), primary rhinoplasty alone; group II (n = 16 patients), nasoalveolar molding alone; group III (n = 14 patients), nasoalveolar molding plus primary rhinoplasty; and group IV (n = 23 patients), nasoalveolar molding plus primary rhinoplasty plus overcorrection. The surgical results were analyzed using photographic records obtained at 5 years of age. A ratio of six measurements was obtained comparing the cleft and noncleft sides. A panel assessment was obtained to grade the appearance of the surgical results. All surgery was performed by the senior author (P.K.T.C.). RESULTS: The results are given for groups I to IV, respectively. The nostril height ratio was 0.73, 0.77, 0.81, and 0.95. The nostril width ratio was 1.23, 1.36, 1.23, and 1.21. The one-fourth medial part of nostril height ratio was 0.70, 0.87, 0.92, and 1.00. The nasal sill height ratio was 0.75, 1.02, 1.07, and 1.07. The nostril area ratio was 0.86, 0.89, 0.95, and 1.08. The nostril height-to-width ratio was 0.58, 0.58, 0.71, and 0.92. Finally, group IV had the best panel assessment. CONCLUSIONS: The results revealed that group IV had the best overall result. Overcorrection of 20 percent was necessary to maintain the nostril height. Further technical modifications are necessary to minimize widening of the nostril width.

Opening of circumaxillary sutures by alternate rapid maxillary expansions and constrictions.

OBJECTIVE: To analyze quantitatively the circumaxillary suture opening after alternate rapid maxillary expansions and constrictions (Alt-RAMEC). MATERIALS AND METHODS: Twelve inbred cats were randomly grouped into two equal groups for 1 week of rapid maxillary expansion (RME) (1 mm/day) or 5 weeks of Alt-RAMEC (1 mm/day). At the end of the experiment, the craniofacial skeleton of each cat was harvested. Each circumaxillary suture was then probed at three sites with a 0.5-mm pointed periodontal probe. A smooth probing without penetration was an ineffective suture opening (<0.5 mm), while a probing with penetration was an effective suture opening (>0.5 mm). For each suture, the quantity of suture opening (%) was the effective suture opening/(effective + ineffective suture opening). The intergroup differences were analyzed by chi-square test (P < .05). RESULTS: Five weeks of Alt-RAMEC opened the circumaxillary sutures significantly more than 1 week of RME. This affected the circumaxillary sutures running coronally and articulating directly to the maxilla (56.9% vs 36.1%, P < .001), the sutures running sagittally, but articulating indirectly to the maxilla (94.4% vs 64.8%, P < .001), and the sutures running coronally, but articulating indirectly to the maxilla (58.3% vs 33.3%, P < .01). The sutures running sagittally were opened significantly more (94.4%-100.0%) than those running coronally (56.9%-58.3%), no matter if they articulated directly or indirectly with the maxilla. CONCLUSIONS: Alt-RAMEC opens both the sagittally and coronally running circumaxillary sutures quantitatively more than conventional RME. However, more than 5 weeks of Alt-RAMEC would be needed to increase the opening of the coronally running circumaxillary sutures. (

Progressive changes of columella length and nasal growth after nasoalveolar molding in bilateral cleft patients: a 3-year follow-up study.

BACKGROUND: The purpose of this study was to assess the progressive changes of columella length and nasal growth after presurgical nasoalveolar molding and primary cheiloplasty in bilateral complete cleft lip-cleft palate infants. METHODS: Twenty-two consecutive complete bilateral cleft lip-cleft palate infants were included. All of them underwent nasoalveolar molding for columella lengthening and retraction of the premaxilla for 3 to 4.5 months before primary cheiloplasty. Standard 1:1 basilar photographs were taken before and after nasoalveolar molding, 1 week after cheiloplasty, and yearly for 3 years. Nasal height and width were measured directly on the photographs. RESULTS: The results revealed that columella length was significantly lengthened after nasoalveolar molding and was further improved after primary cheiloplasty. The columella decreased in length slightly in the first and second years postoperatively and started to increase in length slightly in the third year postoperatively, whereas the rest of the nose grew significantly in height year by year. This consequently appeared as relapse of columella length. The shortage of the columella length was 1.9 mm. CONCLUSIONS: Both presurgical nasoalveolar molding and primary cheiloplasty lengthened the columella in bilateral cleft lip-cleft palate patients. However, there was a relative relapse in columella length because of the differential growth between the columella and the rest of the nose in the first and second years postoperatively.

Effective maxillary orthopedic protraction for growing Class III patients: a clinical application simulates distraction osteogenesis.

The effective maxillary orthopedic protraction is an innovative technique for maxillary protraction in Class III growing patients. It includes three components: a new 2-hinged rapid maxillary expander for a greater amount of anterior displacement of maxilla, repetitive weekly protocol of Alternate Rapid Maxillary Expansion and Constriction (Alt-RAMEC) for disarticulating the maxilla, and intraoral maxillary protraction springs for non-compliant protraction. On average, the maxilla could be protracted for 5.8 mm in 3 months and the result remains stable at least 2 years later. The rationale for this technique is sutural expansion/ protraction osteogenesis. Sutural expansion/ protraction osteogenesis is a form of distraction osteogenesis. However, it still needs to be scrutinized experimentally for the sutural reactions corresponding to the effective maxillary orthopedic protraction.

A new protocol for maxillary protraction in cleft patients: repetitive weekly protocol of alternate rapid maxillary expansions and constrictions.

OBJECTIVE: It was hypothesized that, through a repetitive weekly protocol of Alternate Rapid Maxillary Expansions and Constrictions (Alt-RAMEC), the maxilla in cleft patients could be protracted more effectively than with a single course of rapid maxillary expansion (RME). METHODS: Twenty-six consecutive unilateral cleft lip and palate patients at the age of mixed dentition were included in this prospective clinical study. The rapid maxillary expansion group included the first 16 consecutive patients undergoing 1 week of rapid maxillary expansion (1 mm/day) followed by 5 months, 3 weeks of maxillary protraction. The Alternate Rapid Maxillary Expansions and Constrictions group included the next 10 consecutive patients undergoing 9 weeks of Alternate Rapid Maxillary Expansions and Constrictions followed by 3 months, 3 weeks of maxillary protraction. Daily activation of the weekly expansion or constriction was 1.0 mm. Two-hinged expanders and intraoral maxillary protraction springs were used in both groups. Treatment results were evaluated cephalometrically. RESULTS: The amount of maxillary anterior displacement by the 2-hinged expander in the Alternate Rapid Maxillary Expansions and Constrictions group was 3.0 +/- 0.9 mm at A point, significantly greater than the 1.6 +/- 1.0 mm in the rapid maxillary expansion group. The amount of maxillary advancement with intraoral protraction springs in the Alternate Rapid Maxillary Expansions and Constrictions group was 2.9 +/- 1.9 mm at A point, significantly greater than the 0.9 +/- 1.1 mm in the rapid maxillary expansion group. The overall amount of maxillary advancement in the Alternate Rapid Maxillary Expansions and Constrictions group was 5.8 +/- 2.3 mm at A point. This result remained stable, without significant relapse after 2 years. CONCLUSIONS: Maxillary protraction using the 2-hinged expander, a repetitive weekly protocol of Alternate Rapid Maxillary Expansions and Constrictions, and intraoral protraction springs is most effective, with stable results at 2-year follow-up.