Revista FOP n 13 1571 Braz J Oral Sci. April/June 2008 - Vol. 7 - Number 25 Effects of bonded rapid maxillary expansion applianceEffects of bonded rapid maxillary expansion applianceEffects of bonded rapid maxillary expansion applianceEffects of bonded rapid maxillary expansion applianceEffects of bonded rapid maxillary expansion appliance (brmea) in vertical and sagittal dimensions:(brmea) in vertical and sagittal dimensions:(brmea) in vertical and sagittal dimensions:(brmea) in vertical and sagittal dimensions:(brmea) in vertical and sagittal dimensions: a systematic reviewa systematic reviewa systematic reviewa systematic reviewa systematic review Moara De Rossi, DDS, MSc1; Renata Andréa Salviti de Sá Rocha, DDS, MSc1; Maria Beatriz Duarte Gavião, MD, PhD2 1PhD Student in Pediatric Dentistry 2Professor Department of Pediatric Dentistry, Dental School of Piracicaba, University of Campinas, Brazil Received for publication: March 07, 2008 Accepted: June 12, 2008 Correspondence to: Profa. Dra. Maria Beatriz Duarte Gavião Faculdade de Odontologia de Piracicaba – UNICAMP Av. Limeira 901 CEP 13414-903 Piracicaba, São Paulo, Brasil Phone: +55-19-2106-5368. E-mail: mbgaviao@fop.unicamp.br Abstract Aim: The aim of this systematic review was to evaluate the existing literature about the effects of bonded rapid maxillary expansion appliance (BRMEA) on vertical and sagittal dimensions, and the possible advantages of its use. Methods: A comprehensive search was performed in Medline, Pubmed, and Web of Science full-text electronic journal databases to retrieve English-language articles referring to BRMA. The inclusion criteria to initially select abstracts were: human clinical trials involving the use of BRMEA, measurements made from lateral cephalometric radiographs, no surgical treatments or clinical reports. From a total of 24 abstracts dealing BRMEA, only 7 fulfilled all inclusion criteria. After reading the full text articles, 4 remained. Results: Critical review of these papers revealed a great heterogeneity in the methodologies regarding the evaluation periods, sample characteristics, linear and angular cephalometric measurements. The studies presented on this review showed that the vertical effects are only partially controlled with bonded devices. Conclusion: There is not sufficient evidence to support the use of BRMEA to control the undesirable effects of rapid maxillary expansion (RME). There is a need to study RME with BRMEA considering the patient’s facial patterns in order to determine whether this appliance is actually efficient in controlling the undesirable effects of RME. Key-words: Palatal expansion technique, cephalometry, orthodontics. I n t r o d u c t i o n Rapid maxillary expansion (RME) is a treatment modality for maxillary transverse discrepancy that was introduced by Angell in 18601. Since this time, different appliances have been developed to open the midpalatal suture, such as Hass-type, Hyrax-type and BRMEA (bonded rapid maxillary expansion appliance). While Haas and Hyrax appliances are banded to posterior teeth, the BRMEA is bonded to posterior teeth by a full acrylic surface coverage that encloses all occlusal surfaces. Regarding the maxillary and mandibular responses to RME, several studies2-7 have shown downward and forward maxilla displacement, dental extrusion, lateral rotation of the maxillary segments and cuspal interferences. These events lead to posterior rotation of mandible, open bite and increased vertical face dimension, which can be undesirable for patients with pronounced vertical facial growth patterns. BRMAs have been reported to help eliminating some of the extrusive effects of palatal expansion, due to the additional surface coverage, which limits unwanted tipping and rotation of teeth by increased rigidity8-9. However, there are contradictions in the literature concerning vertical and sagittal changes following RME performed with BRMEA. Therefore, the purpose of this systematic review is to evaluate the existing literature about the effects of BRMEA on vertical and sagittal dimensions, and the possible advantages of its use. Material and Methods This literature review consisted of a comprehensive search in the Medline (from 1966 to week 1 of March 2008), Pubmed (from 1966 to week 1 of March 2008) and Web of Science (from 1945 to week 1 of March 2008) electronic journal databases to retrieve English-language articles that referred to BRMEA. The inclusion criteria to initially select the abstracts were: human clinical trials involving the use of BRMEA, 1572 Database Results Selected % of selected abstracts (7)* Medline 15 4 57.14 PubMed 24 7 100 Web of Science 4 1 14.28 Table 1 - Distribution of the number of abstracts referring to BRMEA, number of abstracts that met the inclusion criteria and percentage of abstracts selected for analysis of the full-text papers for each electronic journal database. *Percentages do not add up to 100% because same references were found in different databases measurements made from lateral cephalometric radiographs (to determine the sagittal and vertical effects of RME with this appliance) and no surgical treatments or clinical reports. Two researchers independently selected the articles to be reviewed by reading their titles and abstracts in each database. All articles that seemed to meet the inclusion criteria on the basis of their abstracts were retrieved. One hundred percent agreement was reached between the two researchers in this phase. The full-text papers were then examined in an independent manner by both researchers. Their reference list was also searched manually for additional relevant publications that could have been missed in the electronic database search. A consensus was reached on which articles actually fulfilled all inclusion criteria and should be included in this systematic review. R e s u l t s The distribution of the number of abstracts referring to BRMEA, number of abstracts that met the inclusion criteria and percentage of abstracts selected for analysis of the full-text papers for each electronic journal database is presented on Table 1. Four articles found in Web of Science were also found in Medline and Pubmed. Fifteen abstracts found in Medline were also found in Pubmed. Pubmed provided the largest number of selected abstracts. Three articles found in Pubmed were not found in the other databases. Only 7 out of 24 abstracts initially selected actually met the inclusion criteria. Four of them referred to studies that used other appliances associated with BRMEA7,10-12. After reading of the full-text articles, 17 of those 4 articles was maintained because it had a group of patients who wore only BRMEA. The other 3 articles10-12 were discarded after analysis because the subjects wore BRMEA and other appliances at the same time, and thus the obtained results could be attributed to the combination of the BRMEA with other therapies, such as edgewise orthodontics10,12, incisor intrusion11 and vertical pull chincup therapy11-12. In the end, only 4 four articles remained 6-9. The methodologies and results of each selected paper are summarized in Table 2. D i s c u s s i o n A critical review of the full-text articles a great heterogeneity in the methodologies regarding the evaluation periods, sample characteristics, such as age and gender, linear and angular cephalometric measurements. Sarver and Johnston8 reported the effects of BRMEA and compared their results to those of Wertz4, whio used a banded appliance. The anterior movement of the maxilla in the bonded sample was lower than that observed in the banded sample. According to the authors8, limited anterior movement of the maxilla with the BRMEA would be an indication for use in Class II patients. This study showed that there was lesser extrusion of the maxilla with the BRMEA and postulated that the thickness of the acrylic acts as a deterrent for extrusion. Asanza et al.9 also studied the difference between a banded appliance and the BRMEA and found anterior movement of the maxilla in Group I (Hyrax) and posterior displacement in group II (BRMEA). In Group I, the maxilla moved inferiorly with subsequent posterior and downward displacement of the mandible. The group treated with the BRMEA showed less inferior movement of the maxilla and a relative stability in the lower face height. These findings can be of importance in the treatment of patients with a long face, in which extrusion of the maxilla or the maxillary dentition would worsen the open bite situation and create more difficulty to treat vertical pattern8- 9. It is important to note that these two studies presented similarities in their methodologies 8-9: the evaluation periods were “before treatment” and “after 3 months of retention period”, the appliances were similar, and 7 of the cephalometric measurements were the same in both studies. This could explain the similar results obtained in both articles. Akkaya et al.6 determined the vertical and sagittal effects of bonded rapid and slow maxillary expansion procedures, and compared these effects between the groups. Comparing these two treatment modalities is not the goal of the present review, but Akkaya’s et al.6 study clearly demonstrates the effects of treatment with BRMEA (Group I). The maxilla showed anterior displacement, and there was a posterior rotation of the mandible after use of BRMEA. Bascifitci and Karaman7 compared the effects of BRME therapy alone to those of BRME combined with vertical chin cap. In Group I (BRMEA only), the mandible rotated downward and backward and the lower anterior facial height increased. In Group II (BRMEA with vertical chin cap), the mandibular plane decreased, and vertical displacement of the maxilla occurred only in Group I, which is in agreement with the findings of Akkaya et al.6 but differ from those of Sarver and Johnston8. The long lower facial height moved anteriorly in both groups. The authors affirm that the use of vertical chin cap during and after RME is important to control the vertical dimension, especially in subjects exhibiting long lower facial height. Braz J Oral Sci. 7(25):1571-1574 Effects of bonded rapid maxillary expansion appliance (brmea) in vertical and sagittal dimensions: a systematic review 1573 Fi rst Au th or Year Stu dy Gr oups Sample Mean Age (years ) Evalua tion Perio ds Expansi on Peri od (Mean s ) Retent io n Peri od (Mean s ) La te ral Ceph alome tr ic Meas u rements Bascifitti 7 2002 I BRMEA II BRMEA with vertica l chin cap I n=17 10 girls 7 boys II n=17 15 girls 2 boys I 12.8 II 12.6 T1- Before treatment T2- After treatment T3- Aft er retent ion I 5.2 we eks II 5.3 weeks I 12.1 weeks II 12.9 weeks SNA; SNB; ANB; SN-MP;SN-PP; PP-MP; SN? PNS; SV? A; SV? B; N -ANS; AN S-Me ; U1P-SN; L1 P-MP; SN? U1; SN? U6; SV? U1 ; SV? L1; MP? L1; Mp? L 1; UL-E; LL-E Akkaya 6 1999 I BRMEA II Bo nded Slow MEA I n=12 5 girls 7 bo ys II n=12 5 girls 7 boys I 11.9 II 12.3 T1-Bef ore treatment T2- After treatment T3- Aft er retent ion N ot cit ed 3 months N-S-Ba; SNA; SN/ANS-PNS; N-Pg-A; SN B; SN/MP; ANB; ANS-PNS/AMP; SN/Occlusal plane; 1/SN; 1´/1; overjet, ove rbite ; E plane Asanza 9 1997 I Hyra x ap plian ce II BRMEA n=14 7 girls 7 boys assigned to 2 groups Range: 8.5-16 yrs T1- Before treatment T2 - After treatm ent N ot cit ed 3 months SNA, SNB, ANB, SN-PP; SN-MP; SN-U1; SN-PNS; SN-ANS; ANS-ME;U6-PP; S- Apt. Sarver 8 1989 I BRMEA II Band ed applia nce (Wertz 4 ) I n=20 14 g irls 6 boys II n =60 37 g irls 23 boys I 10.8 II girls: 7-29 boys: 8 -14 T1- Before treatment T2- After treatment Varied 3 months SNA; SNB; ANB; SN -PP; SN -MP; SN- PNS; SN-ANS; S-A, S-1; SN.1; SN-1 II More downward movement than in Group I I Less downward movement than in Group II II Forward I Backward II Downwar d I Dow nwar d II Ba ck wa rd I Backward Sarver8 II Downward I Less downward movement than in Group II II Backward I Forward II Downwar d I Dow nwar d II Ba ck wa rd I Backward Asanza9 Not relevant for the review analysis I Downward Not relevant for the review analysis I Forward Not relevant for the review analysis I Dow nwar d Not rel ev ant for the rev iew an aly sis I Backward Akkaya6 II No change I Downward II Forward I Forward II No change I Dow nwar d II No ch an ge I Backward Bascifitti 7 Maxilla Vertical Displacementaxillary sagittal Displacement Mandible Vertical Displacement Mandibular Sagittal Displacement Fisrt Author II More downward movement than in Group I I Less downward movement than in Group II II Forward I Backward II Downwar d I Dow nwar d II Ba ck wa rd I Backward Sarver8 II Downward I Less downward movement than in Group II II Backward I Forward II Downwar d I Dow nwar d II Ba ck wa rd I Backward Asanza9 Not relevant for the review analysis I Downward Not relevant for the review analysis I Forward Not relevant for the review analysis I Dow nwar d Not rel ev ant for the rev iew an aly sis I Backward Akkaya6 II No change I Downward II Forward I Forward II No change I Dow nwar d II No ch an ge I Backward Bascifitti 7 Maxilla Vertical Displacementaxillary sagittal Displacement Mandible Vertical Displacement Mandibular Sagittal Displacement Fisrt Author Table 2 - Summary of the methodologies and results of each selected paper. Table2 – Extended Although the BRMEA has been shown to cause less vertical alterations than the banded appliances, some alterations were still present8-9. Downward movement of the maxilla, downward and backward rotation of the mandible using BRMEA alone were verified6,10. Bascifitti and Karaman9 showed a forward displacement of the maxilla. However, in Asanza’s et al.7, and Sarver and Johnston’s8 samples, some subjects exhibited a forward displacement of the maxilla, which can be seen by the SNA variation, that ranged from -5° to +1°, and from -3.6° to 1.7°, respectively. These differences may be attributed to changes in the sample characteristics to the distinct responses that each individual present to the treatments. The patient’s facial pattern is also an important issue to Braz J Oral Sci. 7(25):1571-1574 Effects of bonded rapid maxillary expansion appliance (brmea) in vertical and sagittal dimensions: a systematic review 1574 be considered and can interfere with the choice, response and prognosis of the whole orthopedic and orthodontic treatment. In all research articles retrieved for the present review, the subjects were enrolled without any consideration to their skeletal facial pattern. In this way, we believe that there is a need to study RME with BRMEA considering the patient’s facial patterns in order to determine whether this appliance is actually efficient to control the undesirable effects of RME in all situations. It has been reported that after RME therapy the maxilla will partially3 or completely4 return to its original position. Haas2 has stated that active facial sutures and bones force the maxilla to return to its original position. The tendency of the maxillary skeletal segments to return to their origin can also be attributed to accumulated forces in the circummaxillary articulations13, occlusal forces, surrounding buccal musculature14, and stretched fibers of the palatal mucosa15. Thus, the long-term changes can be of little, if any, clinical significance. The studies presented on this review6,7,9,12 showed that the vertical effects are only partially controlled with bonded devices. However, their observations were limited to the time of use of the BRMEA, including a 3-month stabilization period. This way, further studies should evaluate the dimensional changes occurring at longer periods after removable appliance retention. To the present, the orthodontist should be aware that BRMEA is an option for treatment of bilateral maxillary posterior deficiency, regardless of patient’s facial patterns. Based on this systematic review, it maybe concluded that: the BRMEA caused less downward and backward displacement of the mandible than the banded appliances, but these alterations were not completely absent; there is no consensus in the literature regarding the maxillary sagittal displacement after RME; there is not sufficient evidence to support the use of BRMEA to control the undesirable effects of RME. A c k n o w l e d g e m e n t s This paper was prepared in the discipline “Advanced Pediatric Dentistry Issues” from the PhD program in Dentistry of the Dental School of Piracicaba, State University of Campinas. The authors acknowledge FAPESP ((Process 05/03472-4)and CNPq for the PhD scholarships granted to 1st and 2nd authors, respectively, and the Professors of the Department of Pediatric Dentistry, of the Dental School of Piracicaba, State University of Campinas, for their incentive. R e f e r e n c e s 1. Angell EH. Treatment of irregularity of the permanent or adult teeth. Dent Cosmos. 1860; 1: 540-4. 2. Haas AJ. Rapid expansion of the maxillary dental arch and nasal cavity by opening the midpalatal suture. Angle Orthod. 1961; 31: 73-9. 3. Haas AJ. The treatment of maxillary deficiency by opening the midpalatal suture. Angle Orthod. 1965; 35: 200-17. 4. Wertz RA. Skeletal and dental changes accompanying rapid midpalatal suture opening. Am J Orthod. 1970; 58: 41-66. 5. Wertz RA, Dreskin M. Midpalatal suture opening: a normative study. Am J Orthod. 1977; 71: 367-81. 6. Akkaya S, Lorenzon S, Ucem TT. A comparison of sagittal and vertical effects between bonded rapid and slow maxillary expansion procedures. Eur J Orthod. 1999; 21: 175-80. 7. Basciftci FA, Karaman AI. Effects of a modified acrylic bonded rapid maxillary expansion appliance and vertical chin cap on dentofacial structures. Angle Orthod. 2002; 72: 61-71. 8. Sarver DM, Johnston MW. Skeletal changes in vertical and anterior displacement of the maxilla with bonded rapid palatal expansion appliances. Am J Orthod Dentofacial Orthop. 1989; 95: 462-6. 9. Asanza S, Cisneros GJ, Nieberg LG. Comparison of Hirax and bonded expansion appliances. Angle Orthod. 1997; 67: 15-22. 10. Reed N, Ghosh J, Nanda RS. Comparison of treatment outcomes with banded and bonded rapid palatal expansion appliances. Am J Orthod Dentofacial Orthop. 1999: 116: 31-40. 11. Pearson LE, Pearson BL. Rapid maxillary expansion with incisor intrusion: a study of vertical control. Am J Orthod Dentofacial Orthop. 1999; 115: 576-82. 12. Schulz SO, McNamara JA Jr, Baccetti T, Franchi L. Treatment effects of bonded RME and vertical-pull chincup followed by fixed appliance in patients with increased vertical dimension. Am J Orthod Dentofacial Orthop. 2005; 128: 326-36. 13. Brossman RE, Bennet CG, Merrow WW. Facioskeletal remodeling resulting from a rapid expansion in the monkey (Macaca cynomolglus). Arch Oral Biol. 1973; 18: 987-94. 14. Bishara SE, Staley RN. Maxillary expansion: clinical implications. Am J Orthod Dent Orthop. 1989; 91: 3-14. 15. Maguerza OE, Shapiro PA. Palatal mucoperiostomy: An attempt to reduce relapse after slow maxillary expansion. Am J Orthod. 1980; 78: 548-58. Braz J Oral Sci. 7(25):1571-1574 Effects of bonded rapid maxillary expansion appliance (brmea) in vertical and sagittal dimensions: a systematic review