Accepted Manuscript The dental and skeletal effects of 2-piece and 3-piece SARME procedures with complete mobilization: A retrospective cohort study Karin Habersack, Julia Becker, Oliver Ristow, Gerhard W. Paulus PII:
S0278-2391(14)00440-6
DOI:
10.1016/j.joms.2014.04.013
Reference:
YJOMS 56295
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 30 August 2013 Revised Date:
7 April 2014
Accepted Date: 11 April 2014
Please cite this article as: Habersack K, Becker J, Ristow O, Paulus GW, The dental and skeletal effects of 2-piece and 3-piece SARME procedures with complete mobilization: A retrospective cohort study, Journal of Oral and Maxillofacial Surgery (2014), doi: 10.1016/j.joms.2014.04.013. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
The dental and skeletal effects of 2-piece and 3-piece SARME procedures with complete mobilization: A retrospective cohort study
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Karin Habersack 1, Julia Becker 2, Oliver Ristow 3, Gerhard W. Paulus 4
1 Orthodontist, Private Practice, Herzog-Christoph-Str. 7, D-82362 Weilheim, Germany
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2 Orthodontist, Private Practice, Herzog-Christoph-Str. 7, D-82362 Weilheim, Germany
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3 Resident, Paracelsus Hospital Munich, Department of Oral Maxillofacial Surgery, Klingsorstraße 5, D-81927 Munich, Germany
4 Head of Department, Paracelsus Hospital Munich, Department of Oral Maxillofacial
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Surgery, Klingsorstraße 5, D-81927 Munich, Germany
Dr. Oliver Ristow, M.D. (Corresponding author) Paracelsus Hospital Munich
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Department of Oral Maxillofacial Surgery Klingsorstraße 5
D-81927 Munich Germany
Tel. +49.89.92005.0 Fax +49.89.92005.667 Email: [email protected]
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The dental and skeletal effects of 2-piece and 3-piece SARME procedures with
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complete mobilization: A retrospective cohort study
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Abstract Purpose: The aim of this study was to examine the dental and skeletal widening effects of two different surgically assisted rapid maxillary expansion (SARME) techniques after complete
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mobilization of the maxilla in patients with transverse maxillary hypoplasia and bilateral crossbite.
Methods: A retrospective cohort study design was implemented evaluating two treatment
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groups with complete Le Fort I osteotomy and segmentation of the maxilla followed by
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distraction using a tooth-borne expansion device: patients without crowding of the incisor roots underwent a 2-piece SARME, patients with crowding underwent a 3-piece SARME. Linear transverse measurements were performed on dental casts (intercanine and intersecondmolar distance) and postero-anterior (PA) cephalograms
(skeletal jugulum
distance) before surgery (T1) and at 6 weeks (T2), 6 months (T3), and 12 months (T4)
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postoperatively.
Results: The study included 24 patients (13 women and 11 men, mean age 27, standard
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deviation 18.5 years). Significant maxillary expansion was achieved by both surgical techniques (p 0.05): the 2-piece SARME group (n = 12) included 5 men and 7 women (mean age
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and standard deviation, 29 ± 20.2 years; age range, 17–47 years), while the 3-piece SARME group (n = 12) included 6 men and 6 women (mean age and standard deviation, 25 ± 19.4 years; age range, 17–38 years). Intra-group gain in width
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Intra-group changes of dental gain in width over time (intercanine distance as well as inter second-molar distance) was statistically significant for the 2-piece SARME group (T1 to T2: p=0.000; T2 to T3: p= 0.000; T3 to T4: p=0.008) as well as the 3-piece SARME group (T1 to
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T2: p=0.000; T2 to T3: p= 0.002; T3 to T4: p=0.012). As shown in Table 1 and 2 overall
groups.
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expansion was greater in the posterior part of the maxilla than in the canine region for both
Intra-group changes of skeletal maxillary width over time (skeletal jugulum distance) was statistically significant for the 2-piece SARME group (p=0.000) as well as the 3-piece SARME group from T1 to T2. However, intra-group changes of skeletal maxillary width was not statistically significant for the 2-piece SARME group (T2 to T3: p=1.000; T3 to T4: p= 1.000) as well as the 3-piece SARME group (T2 to T3: p=0.063; T3 to T4: p= 0.125) for the subsequent measurements over time.
ACCEPTED MANUSCRIPT Dental findings Intercanine distances Data for Intercanine distance measurements are presented in Table 1. Note, that there is a significant difference between the 2-piece and the 3-piece SARME group at T2, T3 and T4
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(p0.05).
Change of Inter-second molar distances measurements over time are presented in Table 2. Six weeks after the operation, the distances between the second molars increased by 7.2 mm in the 2-piece SARME group and 6.8 mm in the 3-piece SARME group. Six months postoperatively, 0.6-mm were observed for the 2-piece SARME group and 0.5-mm reductions for the 3-piece SARME group; additional 0.9-mm and 0.4-mm reductions in width occurred after 1 year. The ratio of the postoperative decrease after 1 year (T2 to T4) and initial widening (T1 to T2) was 20.8% and 13.2% in the 2- and 3-piece SARME groups. Results for the repeated measures analysis of variances are displayed in Table 3
ACCEPTED MANUSCRIPT Skeletal findings Skeletal jugulum distance Data for skeletal jugulum distance measurements are presented in Table 1. No significant difference between the 2-piece and the 3-piece SARME group could be shown at any
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measurement point (p>0.05). Change for skeletal jugulum distance measurements over time are presented in Table 2. At T3, a minimal decrease was found in both groups: a total of 0.1 mm for the 2-piece SARME
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group and 0.3 mm for the 3-piece SARME group. At T4, maxillary width was stable in for the 2-piece SARME group; for the 3-piece SARME group, a loss of 0.2 mm was verified.
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Relapse effects were not statistically significant for the 2-piece SARME group (T2-T3: p>0.05; T3-T4: p>0.05) and the 3-piece SARME group (T2-T3: p>0.05; T3-T4: p>0.05).
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Results for the repeated measures analysis of variances are displayed in Table 3
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Discussion The purpose of this study was to examine dental and skeletal maxillary width changes after
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performing 2- or 3-piece SARME procedures following Le Fort I osteotomies with complete mobilization. It was hypothesized that both techniques would achieve significant amounts of expansion with equivalent stability over a 12-month period. The specific aims of the study
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were (i) to measure interdental width changes at the intercanine level, (ii) interdental width
maxillary jugulum landmarks.
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changes at the level of the second molars, and (iii) the skeletal expansion between the bilateral
The results of this study confirmed the hypothesis that both surgical techniques (2- and 3piece SARME) can provide sufficient expansion of the maxilla. There was no significant difference in the expansion of the posterior part of the maxilla between the 2 treatment
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groups, whereas after 6 weeks, the increase in intercanine distance was significantly greater in the 2-piece SARME group. After 12 months, both groups showed some relapse, which was mostly dental and, to a smaller degree, skeletal.
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In cases involving transverse maxillary hypoplasia with bilateral crossbite, it is especially
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important to achieve complete mobilization of the posterior maxillary portion. Insufficient weakening of the osseous structures could lead to undesirable side effects such as (i) intense pain, (ii) excessive buccal tipping or root resorption, (iii) bone resorption, (iv) dehiscences, (v) fractures at the skull base, (vi) nerve compression at several foramina at the skull base, and (vii) asymmetric expansion or extensive relapse 18-22. In this regard, the advantages of the 3-piece SARME over the 2-piece SARME include less esthetic impairments, such as smaller and less conspicuous gaps between the lateral incisors and canines, and reduced risks of damaging the roots of the central incisors, broadening the columella, and nasal septum deviation. In the 3-piece SARME procedure, the temporary lateral tooth gaps after the
ACCEPTED MANUSCRIPT distraction period were less stressful to the patients than the central diastema after a 2-piece SARME procedure. In the literature, most authors reported greater anterior than posterior widening
18, 20, 21
. This
can be explained by the various osteotomy techniques utilized. The zones of major osseous
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resistance are presumed to be the midpalatal suture, the maxillofacial skeletal pillars adjacent to the piriform aperture, the zygomatic buttress, and the pterygomaxillary junction. Holberg et al.
23
tested different stress distributions with a finite element method (FEM) analysis under
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various conditions. In their study, areas of stress could not only be seen at the maxillofacial pillars, but also at the skull base. Under different osteotomy line conditions, they compared
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cases that did not involve any surgery to those involving an osteotomy where only the zygomatic buttress was weakened, a lateral osteotomy, and a Le Fort I osteotomy. These investigators found that the stress distributions in the maxillofacial skeleton and skull base were lowest when osteotomy lines analogous to a Le Fort I osteotomy were analyzed. Thus,
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they recommended Le Fort I osteotomy lines combined with a pterygomaxillary disjunction. Han et al.24 also compared stress distributions in the skull by performing FEM analysis and obtained similar findings. Habersack et al.
25
visualized the effects of conventional rapid
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palatal expansion on 3-dimensional computed tomography (CT) scans, where not only the opening of the midpalatal suture, but also the opening or widening of adjacent structures such
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as the internasal suture, the nasomaxillary sutures, and the frontomaxillary sutures could be observed. In summary, the osteotomy lines described in the literature lay either anterior or lateral 25; lateral and palatinal 9-11; or anterior, lateral, posterior, and medial 4, 13, 26-29 within the maxillary complex. Furthermore, studies using conservative surgical techniques (especially those without a pterygomaxillary disjunction) describe maximal widening in the anterior portion
7, 8, 30-32
. However, cases involving the so-called subtotal Le Fort osteotomies with
pterygomaxillary disjunctions and greater anterior transverse expansion have been reported 33-36
.
4,
ACCEPTED MANUSCRIPT When we performed our complete mobilization technique, posterior expansion was more extensive than anterior expansion and overall widening. This effect could be observed in both groups; however, it was greater with the 3-piece SARME procedure. The reason for such asymmetric widening could be an outward rotation effect of the lateral maxillary segments
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with the greater posterior expansion caused by the anteriorly placed wire sutures at the piriform aperture. The wire sutures may block the segments during distraction, and may exert a greater blocking effect after triple segmentation than after double segmentation if they are
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placed against the direction of expansion. Therefore, great care was taken to position the wires such that they allowed unhindered expansion of the segments. Wire fixation was always
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positioned from a medial hole in the central part of the segmented maxilla to a more lateral hole at the piriform aperture above the osteotomy line. In triple-segmented maxilla, the lower hole was positioned even more medially than in the 2-piece procedures, such that the wires did not cross the lateral segments.
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When sagittal, vertical, and transversal positional changes of the maxillary segments are performed simultaneously in non-distraction cases, complete mobilization after a downfracture procedure is necessary, including bone fixation. For the stabilization of a 1-
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piece maxillary osteotomy, it has been proven that semirigid bone fixation with only 1 miniplate at the piriform aperture on each side is effective and sufficient
37, 38
. For
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simultaneous sagittal or vertical 3-dimensional Le Fort I osteotomies with a distraction osteogenesis technique, suspension wires, microplates, and miniplates have been used. Pinto et al.
16
stressed the importance of the malleability of these fixation elements. In our study,
only 2 wire sutures were used for bone fixation, and not a single case of disturbed bone healing was observed. As the rigid Hyrax expansion device additionally stabilized the 2 or 3 maxillary segments, there was no need to change the method used for bone fixation. Our findings showed that the increase in the intercanine width was less than that in the intermolar width in the 3-piece SARME group. This could be attributed to the rapid and
ACCEPTED MANUSCRIPT almost spontaneous closure of the gap between the lateral incisors and canines after the end of distraction in some cases. In our study, the first postoperative measurements were performed 6 weeks after surgery. At that time, distraction had already been completed 3 to 4 weeks prior, and the gaps were nearly closed, even without postoperative orthodontic treatment. The early
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spontaneous movement of the canines into the lateral gaps in group 2 was the main reason for the lesser intercanine distance compared to the posterior widening, and in comparison to group 1 at T2.
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An anatomic biomechanical study has shown that expansion is never symmetrical, regardless of whether tooth- or bone-borne devices are utilized 39. Asymmetrical expansion may occur 3-
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dimensionally as a result of the tipping of segments, greater anterior or posterior widening, more inferior or superior device positioning, and greater expansion of the right or left sides. Some authors have sought to overcome this asymmetric outcome by modifying the expansion device design
22, 39-41
, using different device placement techniques
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, or by using
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intermaxillary elastics during the distraction period. The surgical technique including a complete mobilization of the maxilla after a downfracture procedure is corroborated by the biomechanical study conducted by Koudstaal et al.
39
, which concluded that the pterygoid
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region and the surrounding soft tissues affect the amount of resistance on each side. If there is incomplete mobilization, even if a so-called disjunction of the pterygomaxillary suture is
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performed with a chisel or an osteotome without a downfracture maneuver, asymmetric widening resulting from the surrounding muscles and ligaments can occur. Chamberland and Profitt 1 analyzed SARME patients in whom Le Fort osteotomies, including a separation of the pterygoid junction, were performed. They found that immediately after expansion, 47% of the widening was skeletal and 53% was dental. In our study, we compared the distance changes between the jugulum landmarks on PA cephalograms to the inter-second molar distance changes on plaster models. The inter-second molar distance increased by 7.2 mm in the 2-piece SARME group and 6.8 mm in the 3-piece SARME group at T2, compared
ACCEPTED MANUSCRIPT with skeletal width changes of 7 and 6 mm, respectively, between the landmarks “J” and “J´”. This comparison revealed a major skeletal widening effect with only minor dental or segmental tipping. We found 97.2% skeletal and 2.8% dental widening in group 1 and 88.2% skeletal and 11.8% dental widening in group 2 in the posterior part of the maxilla 6 weeks
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after surgery. This shows that complete mobilization of the maxilla leads to a predominantly skeletal expansion. Our study could only detect skeletal changes in the posterior portion at landmark J, whereas skeletal changes in the anterior part of the maxilla could not be analyzed
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on PA cephalograms. It would be possible to examine these skeletal effects using 3dimensional imaging modalities such as CT or DVT, as performed in other studies 42; we did
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not follow such protocols, as in our opinion, it is unnecessary to expose each patient to a 4fold higher radiation dose by using these imaging methods.
In further studies, CT or DVT examinations could be used to compare 1 preoperative and 1 postoperative tomogram with the agreement of an ethical commission. A prospective study
showed posterior tipping
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utilizing low-dose helical CT acquired at the start of orthodontic treatment and after treatment 42
. The advantage of this method is that it enables more
measurements at different landmarks. However, a disadvantage is the limitation of only 2
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radiology examinations compared to our evaluation of 4 examinations. In the literature, the term “relapse” is used to describe the ratio between the interdental width
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gained by distraction and the post-distraction decrease. However, some differentiation between skeletal relapse and dental changes is necessary. Skeletal relapse is mainly caused by a passive reaction during wound healing and by biomechanical forces, which are not influenced by the surgeon, whereas dental changes after the distraction period are predominantly the result of active orthodontic treatment. A comparison of the post-distraction decreases in dental and skeletal widths showed that there is only minimal skeletal relapse, but there are major dental changes. The results show a reduction in interdental distances as well as in skeletal widths after the period of distraction.
ACCEPTED MANUSCRIPT The inter-second molar widths on the dental casts decreased 1.5 mm in the 2-piece SARME group and 0.9 mm in the 3-piece SARME group from T2 to T4, compared with skeletal distance reductions of only 0.1 and 0.5 mm, respectively. Therefore, the major reduction was dental in both groups: 93% dental versus 7% skeletal in the 2-piece SARME group and 64%
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dental versus 36% skeletal in the 3-piece group. As Vilani et al. reported in their metaanalysis, significant relapse mostly occurs in the intercanine region 43.
In our study, the intercanine width decreased by 22.1% in group 1 and 20% in group 2, and
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the inter-second molar distances reduced by 10.8 and 25.4% in the 2-piece and 3-piece SARME groups, respectively, after 1 year. In the literature, the values range from 0–23% for 4-14, 26, 30, 32
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intercanine distance and 0–33% for intermolar distance
. It is difficult to compare
these different findings because of the various initial dental situations as well as differences in orthodontic and surgical treatment modalities. In our cases, some orthodontists previously stopped the distraction maneuver very late in order to create a transverse overcorrection. In
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some cases, buccal non-occlusion resulted after distraction, which later had to be corrected orthodontically by tipping the teeth palatally.
Our results suggest that it is unnecessary to perform this kind of overcorrection in adults,
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contrary to the requirements in patients undergoing non-surgically assisted rapid palatal expansion (RPE). Further investigations of SARME procedures and complete mobilization of
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the maxilla without transversal overcorrection are necessary to verify the present results.
Conclusion
Both 2-piece and 3-piece SARME techniques led to sufficient skeletal widening effects, especially in the posterior maxilla. Some relapse was observed after a follow-up period of 12 months, which was mostly dental and, to a smaller degree, skeletal. The advantages of 3-piece SARME can be summarized as follows: a higher level of patient comfort can be achieved by avoiding a medial gap after surgery; the risk of damaging crowded incisor roots is reduced;
ACCEPTED MANUSCRIPT and the smaller gaps between the lateral incisors and canines are less conspicuous and tend to close more rapidly. Esthetic impairment is sometimes seen in patients who undergo 2-piece SARME; however, impairments such as nasal septum deviation and deformation of the
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columella do not occur in those who undergo 3-piece SARME procedures.
Conflicts of Interest
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The authors report no conflicts of interest.
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References 1.
Chamberland S, Proffit WR: Closer look at the stability of surgically assisted rapid
2.
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palatal expansion. J Oral Maxillofac Surg 66:1895, 2008 Koudstaal MJ, Poort LJ, van der Wal KG et al.: Surgically assisted rapid maxillary
expansion (SARME): a review of the literature. Int J Oral Maxillofac Surg 34:709, 2005 Suri L, Taneja P: Surgically assisted rapid palatal expansion: a literature review. Am J
SC
3.
Orthod Dentofacial Orthop 133:290, 2008
Bell RA: A review of maxillary expansion in relation to rate of expansion and patient's
age. Am J Orthod 81:32, 1982 5.
Timms DJ: A study of basal movement with rapid maxillary expansion. Am J Orthod
77:500, 1980
Bailey LJ, White RP, Jr., Proffit WR, Turvey TA: Segmental LeFort I osteotomy for
TE D
6.
M AN U
4.
management of transverse maxillary deficiency. J Oral Maxillofac Surg 55:728, 1997 7.
Işeri H, Tekkaya AE, Oztan O, Bilgiç S: Biomechanical effects of rapid maxillary
20:347, 1998
Jafari A, Shetty KS, Kumar M: Study of stress distribution and displacement of
AC C
8.
EP
expansion on the craniofacial skeleton, studied by the finite element method. Eur J Orthod
various craniofacial structures following application of transverse orthopedic forces--a threedimensional FEM study. Angle Orthod 73:12, 2003 9.
Pogrel MA, Kaban LB, Vargervik K, Baumrind S: Surgically assisted rapid maxillary
expansion in adults. Int J Adult Orthodon Orthognath Surg 7:37, 1992 10.
Northway WM, Meade JB, Jr.: Surgically assisted rapid maxillary expansion: a
comparison of technique, response, and stability. Angle Orthod 67:309, 1997
ACCEPTED MANUSCRIPT 11.
Strömberg C, Holm J: Surgically assisted, rapid maxillary expansion in adults. A
retrospective long-term follow-up study. J Craniomaxillofac Surg 23:222, 1995 12.
Anttila A, Finne K, Keski-Nisula K et al.: Feasibility and long-term stability of
surgically assisted rapid maxillary expansion with lateral osteotomy. Eur J Orthod 26:391,
13.
RI PT
2004
Berger JL, Pangrazio-Kulbersh V, Borgula T, Kaczynski R: Stability of orthopedic
and surgically assisted rapid palatal expansion over time. Am J Orthod Dentofacial Orthop
14.
Byloff FK, Mossaz CF: Skeletal and dental changes following surgically assisted rapid
M AN U
palatal expansion. Eur J Orthod 26:403, 2004 15.
SC
114:638, 1998
Braun S, Lee KG, Legan HL: A reexamination of various extraoral appliances in light
of recent research findings. Angle Orthod 69:81, 1999 16.
Pinto LP, Bell WH, Chu S, Buschang PH: Simultaneous 3-dimensional Le Fort
17.
TE D
I/distraction osteogenesis technique: positional changes. J Oral Maxillofac Surg 67:32, 2009 Paulus GW: Verschiedene chirurgische Möglichkeiten der Oberkieferverbreiterung. In
17. Symposium für Gesichtschirurgie, (ed. Kampen, Sylt, 2007. Cureton SL, Cuenin M: Surgically assisted rapid palatal expansion: orthodontic
EP
18.
preparation for clinical success. Am J Orthod Dentofacial Orthop 116:46, 1999 Kilic E, Kilic B, Kurt G et al.: Effects of surgically assisted rapid palatal expansion
AC C
19.
with and without pterygomaxillary disjunction on dental and skeletal structures: a retrospective review. Oral Surg Oral Med Oral Pathol Oral Radiol 115:167, 2013 20.
Schimming R, Feller KU, Herzmann K, Eckelt U: Surgical and orthodontic rapid
palatal expansion in adults using Glassman's technique: retrospective study. Br J Oral Maxillofac Surg 38:66, 2000 21.
Woods M, Wiesenfeld D, Probert T: Surgically-assisted maxillary expansion. Aust
Dent J 42:38, 1997
ACCEPTED MANUSCRIPT 22.
Pary A, Cal-Neto JP: A simple method to treat asymmetric expansions in three-
segment surgically assisted rapid maxillary expansion. J Oral Maxillofac Surg 71:2130, 2013 23.
Holberg C: Effects of rapid maxillary expansion on the cranial base--an FEM-analysis.
J Orofac Orthop 66:54, 2005 Han UA, Kim Y, Park JU: Three-dimensional finite element analysis of stress
RI PT
24.
distribution and displacement of the maxilla following surgically assisted rapid maxillary expansion. J Craniomaxillofac Surg 37:145, 2009
Habersack K, Karoglan A, Sommer B, Benner KU: High-resolution multislice
SC
25.
computerized tomography with multiplanar and 3-dimensional reformation imaging in rapid
26.
M AN U
palatal expansion. Am J Orthod Dentofacial Orthop 131:776, 2007
Bays RA, Greco JM: Surgically assisted rapid palatal expansion: an outpatient
technique with long-term stability. J Oral Maxillofac Surg 50:110, 1992 27.
Bell WH, Epker BN: Surgical-orthodontic expansion of the maxilla. Am J Orthod
28.
TE D
70:517, 1976
Fish LC, Epker BN: Prevention of relapse in surgical-orthodontic treatment. Part 1.
Mandibular procedures. J Clin Orthod 20:826, 1986 Turvey TA: Maxillary expansion: a surgical technique based on surgical-orthodontic
EP
29.
treatment objectives and anatomical considerations. J Maxillofac Surg 13:51, 1985 Haas AJ: Palatal expansion: just the beginning of dentofacial orthopedics. Am J
AC C
30.
Orthod 57:219, 1970 31.
Memikoglu TU, Işeri H: Effects of a bonded rapid maxillary expansion appliance
during orthodontic treatment. Angle Orthod 69:251, 1999 32.
Wertz RA: Skeletal and dental changes accompanying rapid midpalatal suture
opening. Am J Orthod 58:41, 1970
ACCEPTED MANUSCRIPT 33.
Goldenberg DC, Alonso N, Goldenberg FC et al.: Using computed tomography to
evaluate maxillary changes after surgically assisted rapid palatal expansion. J Craniofac Surg 18:302, 2007 34.
Landes CA, Laudemann K, Petruchin O et al.: Comparison of bipartite versus tripartite
RI PT
osteotomy for maxillary transversal expansion using 3-dimensional preoperative and postexpansion computed tomography data. J Oral Maxillofac Surg 67:2287, 2009 35.
Zemann W, Schanbacher M, Feichtinger M et al.: Dentoalveolar changes after
Oral Pathol Oral Radiol Endod 107:36, 2009
Landes CA, Laudemann K, Petruchin O et al.: Advantages and limits of 3-segment
M AN U
36.
SC
surgically assisted maxillary expansion: a three-dimensional evaluation. Oral Surg Oral Med
(paramedian) versus 2-segment (median) surgically assisted rapid maxillary expansion (SARME). Oral Surg Oral Med Oral Pathol Oral Radiol 113:29, 2012 37.
Murray RA, Upton LG, Rottman KR: Comparison of the postsurgical stability of the
38.
Paulus GW: Semirigid bone fixation: a new concept in orthognathic surgery. J
Craniofac Surg 2:146, 1991
Koudstaal MJ, Smeets JB, Kleinrensink GJ et al.: Relapse and stability of surgically
EP
39.
TE D
Le Fort I osteotomy using 2- and 4-plate fixation. J Oral Maxillofac Surg 61:574, 2003
assisted rapid maxillary expansion: an anatomic biomechanical study. J Oral Maxillofac Surg
40.
AC C
67:10, 2009
Matteini C, Mommaerts MY: Posterior transpalatal distraction with pterygoid
disjunction: a short-term model study. Am J Orthod Dentofacial Orthop 120:498, 2001 41.
Zahl C, Gerlach KL: [Palatal distractor. An innovative approach for palatal
expansion]. Mund Kiefer Gesichtschir 6:446, 2002 42.
Magnusson A, Bjerklin K, Kim H et al.: Three-dimensional assessment of transverse
skeletal changes after surgically assisted rapid maxillary expansion and orthodontic treatment:
ACCEPTED MANUSCRIPT a prospective computerized tomography study. Am J Orthod Dentofacial Orthop 142:825, 2012 43.
Vilani GN, Mattos CT, de Oliveira Ruellas AC, Maia LC: Long-term dental and
skeletal changes in patients submitted to surgically assisted rapid maxillary expansion: a
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meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol 114:689, 2012
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Figure legends
Fig. 1: (a + b) The horizontal, midline palatal, and transalveolar osteotomy lines (red) of
the anteriorly placed wire sutures at the piriform aperture (white).
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patients treated with the 2-piece SARME technique (group 1) are displayed. (b) Please note
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Fig. 2: (a + b) The horizontal, paramedian palatal, and transalveolar osteotomy lines (red) of patients treated with the 3-piece SARME technique (group 2) are displayed. (b) Please note
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the anteriorly placed wire sutures at the piriform aperture (white).
Fig. 3: Changes in the skeletal jugulum landmarks of the osteotomized lateral maxilla after a
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2-piece SARME procedure (group 1).
Fig. 4: Changes in the skeletal jugulum landmarks of the osteotomized lateral maxilla after a
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3-piece SARME procedure (group 2).
ACCEPTED MANUSCRIPT Table 1: Comparison of interdental and skeletal width, primary endpoint
N
Mean
SD
p-value*
T1
12
32.3
2.5
12
31.6
1.2
0.418
T2
12
39
2.8
12
34.5
2.3
T3
12
38.1
2.6
12
34
2.4
T4
12
37.5
2.5
12
33.9
2.3
T1
11
55
3
12
53.5
3.5
0.318
T2
11
62.2
3.1
12
60.3
3.2
0.176
T3
11
61.5
2.9
T4
11
60.7
3.8
T1
12
53.7
3
T2
12
60.7
3.1
T3
12
60.6
T4
12
60.6
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Mean SD
S0278-2391(14)00440-6
DOI:
10.1016/j.joms.2014.04.013
Reference:
YJOMS 56295
To appear in:
Journal of Oral and Maxillofacial Surgery
Received Date: 30 August 2013 Revised Date:
7 April 2014
Accepted Date: 11 April 2014
Please cite this article as: Habersack K, Becker J, Ristow O, Paulus GW, The dental and skeletal effects of 2-piece and 3-piece SARME procedures with complete mobilization: A retrospective cohort study, Journal of Oral and Maxillofacial Surgery (2014), doi: 10.1016/j.joms.2014.04.013. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
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The dental and skeletal effects of 2-piece and 3-piece SARME procedures with complete mobilization: A retrospective cohort study
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Karin Habersack 1, Julia Becker 2, Oliver Ristow 3, Gerhard W. Paulus 4
1 Orthodontist, Private Practice, Herzog-Christoph-Str. 7, D-82362 Weilheim, Germany
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2 Orthodontist, Private Practice, Herzog-Christoph-Str. 7, D-82362 Weilheim, Germany
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3 Resident, Paracelsus Hospital Munich, Department of Oral Maxillofacial Surgery, Klingsorstraße 5, D-81927 Munich, Germany
4 Head of Department, Paracelsus Hospital Munich, Department of Oral Maxillofacial
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Surgery, Klingsorstraße 5, D-81927 Munich, Germany
Dr. Oliver Ristow, M.D. (Corresponding author) Paracelsus Hospital Munich
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Department of Oral Maxillofacial Surgery Klingsorstraße 5
D-81927 Munich Germany
Tel. +49.89.92005.0 Fax +49.89.92005.667 Email: [email protected]
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The dental and skeletal effects of 2-piece and 3-piece SARME procedures with
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complete mobilization: A retrospective cohort study
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Abstract Purpose: The aim of this study was to examine the dental and skeletal widening effects of two different surgically assisted rapid maxillary expansion (SARME) techniques after complete
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mobilization of the maxilla in patients with transverse maxillary hypoplasia and bilateral crossbite.
Methods: A retrospective cohort study design was implemented evaluating two treatment
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groups with complete Le Fort I osteotomy and segmentation of the maxilla followed by
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distraction using a tooth-borne expansion device: patients without crowding of the incisor roots underwent a 2-piece SARME, patients with crowding underwent a 3-piece SARME. Linear transverse measurements were performed on dental casts (intercanine and intersecondmolar distance) and postero-anterior (PA) cephalograms
(skeletal jugulum
distance) before surgery (T1) and at 6 weeks (T2), 6 months (T3), and 12 months (T4)
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postoperatively.
Results: The study included 24 patients (13 women and 11 men, mean age 27, standard
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deviation 18.5 years). Significant maxillary expansion was achieved by both surgical techniques (p 0.05): the 2-piece SARME group (n = 12) included 5 men and 7 women (mean age
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and standard deviation, 29 ± 20.2 years; age range, 17–47 years), while the 3-piece SARME group (n = 12) included 6 men and 6 women (mean age and standard deviation, 25 ± 19.4 years; age range, 17–38 years). Intra-group gain in width
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Intra-group changes of dental gain in width over time (intercanine distance as well as inter second-molar distance) was statistically significant for the 2-piece SARME group (T1 to T2: p=0.000; T2 to T3: p= 0.000; T3 to T4: p=0.008) as well as the 3-piece SARME group (T1 to
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T2: p=0.000; T2 to T3: p= 0.002; T3 to T4: p=0.012). As shown in Table 1 and 2 overall
groups.
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expansion was greater in the posterior part of the maxilla than in the canine region for both
Intra-group changes of skeletal maxillary width over time (skeletal jugulum distance) was statistically significant for the 2-piece SARME group (p=0.000) as well as the 3-piece SARME group from T1 to T2. However, intra-group changes of skeletal maxillary width was not statistically significant for the 2-piece SARME group (T2 to T3: p=1.000; T3 to T4: p= 1.000) as well as the 3-piece SARME group (T2 to T3: p=0.063; T3 to T4: p= 0.125) for the subsequent measurements over time.
ACCEPTED MANUSCRIPT Dental findings Intercanine distances Data for Intercanine distance measurements are presented in Table 1. Note, that there is a significant difference between the 2-piece and the 3-piece SARME group at T2, T3 and T4
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(p0.05).
Change of Inter-second molar distances measurements over time are presented in Table 2. Six weeks after the operation, the distances between the second molars increased by 7.2 mm in the 2-piece SARME group and 6.8 mm in the 3-piece SARME group. Six months postoperatively, 0.6-mm were observed for the 2-piece SARME group and 0.5-mm reductions for the 3-piece SARME group; additional 0.9-mm and 0.4-mm reductions in width occurred after 1 year. The ratio of the postoperative decrease after 1 year (T2 to T4) and initial widening (T1 to T2) was 20.8% and 13.2% in the 2- and 3-piece SARME groups. Results for the repeated measures analysis of variances are displayed in Table 3
ACCEPTED MANUSCRIPT Skeletal findings Skeletal jugulum distance Data for skeletal jugulum distance measurements are presented in Table 1. No significant difference between the 2-piece and the 3-piece SARME group could be shown at any
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measurement point (p>0.05). Change for skeletal jugulum distance measurements over time are presented in Table 2. At T3, a minimal decrease was found in both groups: a total of 0.1 mm for the 2-piece SARME
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group and 0.3 mm for the 3-piece SARME group. At T4, maxillary width was stable in for the 2-piece SARME group; for the 3-piece SARME group, a loss of 0.2 mm was verified.
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Relapse effects were not statistically significant for the 2-piece SARME group (T2-T3: p>0.05; T3-T4: p>0.05) and the 3-piece SARME group (T2-T3: p>0.05; T3-T4: p>0.05).
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Results for the repeated measures analysis of variances are displayed in Table 3
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Discussion The purpose of this study was to examine dental and skeletal maxillary width changes after
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performing 2- or 3-piece SARME procedures following Le Fort I osteotomies with complete mobilization. It was hypothesized that both techniques would achieve significant amounts of expansion with equivalent stability over a 12-month period. The specific aims of the study
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were (i) to measure interdental width changes at the intercanine level, (ii) interdental width
maxillary jugulum landmarks.
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changes at the level of the second molars, and (iii) the skeletal expansion between the bilateral
The results of this study confirmed the hypothesis that both surgical techniques (2- and 3piece SARME) can provide sufficient expansion of the maxilla. There was no significant difference in the expansion of the posterior part of the maxilla between the 2 treatment
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groups, whereas after 6 weeks, the increase in intercanine distance was significantly greater in the 2-piece SARME group. After 12 months, both groups showed some relapse, which was mostly dental and, to a smaller degree, skeletal.
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In cases involving transverse maxillary hypoplasia with bilateral crossbite, it is especially
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important to achieve complete mobilization of the posterior maxillary portion. Insufficient weakening of the osseous structures could lead to undesirable side effects such as (i) intense pain, (ii) excessive buccal tipping or root resorption, (iii) bone resorption, (iv) dehiscences, (v) fractures at the skull base, (vi) nerve compression at several foramina at the skull base, and (vii) asymmetric expansion or extensive relapse 18-22. In this regard, the advantages of the 3-piece SARME over the 2-piece SARME include less esthetic impairments, such as smaller and less conspicuous gaps between the lateral incisors and canines, and reduced risks of damaging the roots of the central incisors, broadening the columella, and nasal septum deviation. In the 3-piece SARME procedure, the temporary lateral tooth gaps after the
ACCEPTED MANUSCRIPT distraction period were less stressful to the patients than the central diastema after a 2-piece SARME procedure. In the literature, most authors reported greater anterior than posterior widening
18, 20, 21
. This
can be explained by the various osteotomy techniques utilized. The zones of major osseous
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resistance are presumed to be the midpalatal suture, the maxillofacial skeletal pillars adjacent to the piriform aperture, the zygomatic buttress, and the pterygomaxillary junction. Holberg et al.
23
tested different stress distributions with a finite element method (FEM) analysis under
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various conditions. In their study, areas of stress could not only be seen at the maxillofacial pillars, but also at the skull base. Under different osteotomy line conditions, they compared
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cases that did not involve any surgery to those involving an osteotomy where only the zygomatic buttress was weakened, a lateral osteotomy, and a Le Fort I osteotomy. These investigators found that the stress distributions in the maxillofacial skeleton and skull base were lowest when osteotomy lines analogous to a Le Fort I osteotomy were analyzed. Thus,
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they recommended Le Fort I osteotomy lines combined with a pterygomaxillary disjunction. Han et al.24 also compared stress distributions in the skull by performing FEM analysis and obtained similar findings. Habersack et al.
25
visualized the effects of conventional rapid
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palatal expansion on 3-dimensional computed tomography (CT) scans, where not only the opening of the midpalatal suture, but also the opening or widening of adjacent structures such
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as the internasal suture, the nasomaxillary sutures, and the frontomaxillary sutures could be observed. In summary, the osteotomy lines described in the literature lay either anterior or lateral 25; lateral and palatinal 9-11; or anterior, lateral, posterior, and medial 4, 13, 26-29 within the maxillary complex. Furthermore, studies using conservative surgical techniques (especially those without a pterygomaxillary disjunction) describe maximal widening in the anterior portion
7, 8, 30-32
. However, cases involving the so-called subtotal Le Fort osteotomies with
pterygomaxillary disjunctions and greater anterior transverse expansion have been reported 33-36
.
4,
ACCEPTED MANUSCRIPT When we performed our complete mobilization technique, posterior expansion was more extensive than anterior expansion and overall widening. This effect could be observed in both groups; however, it was greater with the 3-piece SARME procedure. The reason for such asymmetric widening could be an outward rotation effect of the lateral maxillary segments
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with the greater posterior expansion caused by the anteriorly placed wire sutures at the piriform aperture. The wire sutures may block the segments during distraction, and may exert a greater blocking effect after triple segmentation than after double segmentation if they are
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placed against the direction of expansion. Therefore, great care was taken to position the wires such that they allowed unhindered expansion of the segments. Wire fixation was always
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positioned from a medial hole in the central part of the segmented maxilla to a more lateral hole at the piriform aperture above the osteotomy line. In triple-segmented maxilla, the lower hole was positioned even more medially than in the 2-piece procedures, such that the wires did not cross the lateral segments.
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When sagittal, vertical, and transversal positional changes of the maxillary segments are performed simultaneously in non-distraction cases, complete mobilization after a downfracture procedure is necessary, including bone fixation. For the stabilization of a 1-
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piece maxillary osteotomy, it has been proven that semirigid bone fixation with only 1 miniplate at the piriform aperture on each side is effective and sufficient
37, 38
. For
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simultaneous sagittal or vertical 3-dimensional Le Fort I osteotomies with a distraction osteogenesis technique, suspension wires, microplates, and miniplates have been used. Pinto et al.
16
stressed the importance of the malleability of these fixation elements. In our study,
only 2 wire sutures were used for bone fixation, and not a single case of disturbed bone healing was observed. As the rigid Hyrax expansion device additionally stabilized the 2 or 3 maxillary segments, there was no need to change the method used for bone fixation. Our findings showed that the increase in the intercanine width was less than that in the intermolar width in the 3-piece SARME group. This could be attributed to the rapid and
ACCEPTED MANUSCRIPT almost spontaneous closure of the gap between the lateral incisors and canines after the end of distraction in some cases. In our study, the first postoperative measurements were performed 6 weeks after surgery. At that time, distraction had already been completed 3 to 4 weeks prior, and the gaps were nearly closed, even without postoperative orthodontic treatment. The early
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spontaneous movement of the canines into the lateral gaps in group 2 was the main reason for the lesser intercanine distance compared to the posterior widening, and in comparison to group 1 at T2.
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An anatomic biomechanical study has shown that expansion is never symmetrical, regardless of whether tooth- or bone-borne devices are utilized 39. Asymmetrical expansion may occur 3-
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dimensionally as a result of the tipping of segments, greater anterior or posterior widening, more inferior or superior device positioning, and greater expansion of the right or left sides. Some authors have sought to overcome this asymmetric outcome by modifying the expansion device design
22, 39-41
, using different device placement techniques
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, or by using
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intermaxillary elastics during the distraction period. The surgical technique including a complete mobilization of the maxilla after a downfracture procedure is corroborated by the biomechanical study conducted by Koudstaal et al.
39
, which concluded that the pterygoid
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region and the surrounding soft tissues affect the amount of resistance on each side. If there is incomplete mobilization, even if a so-called disjunction of the pterygomaxillary suture is
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performed with a chisel or an osteotome without a downfracture maneuver, asymmetric widening resulting from the surrounding muscles and ligaments can occur. Chamberland and Profitt 1 analyzed SARME patients in whom Le Fort osteotomies, including a separation of the pterygoid junction, were performed. They found that immediately after expansion, 47% of the widening was skeletal and 53% was dental. In our study, we compared the distance changes between the jugulum landmarks on PA cephalograms to the inter-second molar distance changes on plaster models. The inter-second molar distance increased by 7.2 mm in the 2-piece SARME group and 6.8 mm in the 3-piece SARME group at T2, compared
ACCEPTED MANUSCRIPT with skeletal width changes of 7 and 6 mm, respectively, between the landmarks “J” and “J´”. This comparison revealed a major skeletal widening effect with only minor dental or segmental tipping. We found 97.2% skeletal and 2.8% dental widening in group 1 and 88.2% skeletal and 11.8% dental widening in group 2 in the posterior part of the maxilla 6 weeks
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after surgery. This shows that complete mobilization of the maxilla leads to a predominantly skeletal expansion. Our study could only detect skeletal changes in the posterior portion at landmark J, whereas skeletal changes in the anterior part of the maxilla could not be analyzed
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on PA cephalograms. It would be possible to examine these skeletal effects using 3dimensional imaging modalities such as CT or DVT, as performed in other studies 42; we did
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not follow such protocols, as in our opinion, it is unnecessary to expose each patient to a 4fold higher radiation dose by using these imaging methods.
In further studies, CT or DVT examinations could be used to compare 1 preoperative and 1 postoperative tomogram with the agreement of an ethical commission. A prospective study
showed posterior tipping
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utilizing low-dose helical CT acquired at the start of orthodontic treatment and after treatment 42
. The advantage of this method is that it enables more
measurements at different landmarks. However, a disadvantage is the limitation of only 2
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radiology examinations compared to our evaluation of 4 examinations. In the literature, the term “relapse” is used to describe the ratio between the interdental width
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gained by distraction and the post-distraction decrease. However, some differentiation between skeletal relapse and dental changes is necessary. Skeletal relapse is mainly caused by a passive reaction during wound healing and by biomechanical forces, which are not influenced by the surgeon, whereas dental changes after the distraction period are predominantly the result of active orthodontic treatment. A comparison of the post-distraction decreases in dental and skeletal widths showed that there is only minimal skeletal relapse, but there are major dental changes. The results show a reduction in interdental distances as well as in skeletal widths after the period of distraction.
ACCEPTED MANUSCRIPT The inter-second molar widths on the dental casts decreased 1.5 mm in the 2-piece SARME group and 0.9 mm in the 3-piece SARME group from T2 to T4, compared with skeletal distance reductions of only 0.1 and 0.5 mm, respectively. Therefore, the major reduction was dental in both groups: 93% dental versus 7% skeletal in the 2-piece SARME group and 64%
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dental versus 36% skeletal in the 3-piece group. As Vilani et al. reported in their metaanalysis, significant relapse mostly occurs in the intercanine region 43.
In our study, the intercanine width decreased by 22.1% in group 1 and 20% in group 2, and
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the inter-second molar distances reduced by 10.8 and 25.4% in the 2-piece and 3-piece SARME groups, respectively, after 1 year. In the literature, the values range from 0–23% for 4-14, 26, 30, 32
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intercanine distance and 0–33% for intermolar distance
. It is difficult to compare
these different findings because of the various initial dental situations as well as differences in orthodontic and surgical treatment modalities. In our cases, some orthodontists previously stopped the distraction maneuver very late in order to create a transverse overcorrection. In
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some cases, buccal non-occlusion resulted after distraction, which later had to be corrected orthodontically by tipping the teeth palatally.
Our results suggest that it is unnecessary to perform this kind of overcorrection in adults,
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contrary to the requirements in patients undergoing non-surgically assisted rapid palatal expansion (RPE). Further investigations of SARME procedures and complete mobilization of
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the maxilla without transversal overcorrection are necessary to verify the present results.
Conclusion
Both 2-piece and 3-piece SARME techniques led to sufficient skeletal widening effects, especially in the posterior maxilla. Some relapse was observed after a follow-up period of 12 months, which was mostly dental and, to a smaller degree, skeletal. The advantages of 3-piece SARME can be summarized as follows: a higher level of patient comfort can be achieved by avoiding a medial gap after surgery; the risk of damaging crowded incisor roots is reduced;
ACCEPTED MANUSCRIPT and the smaller gaps between the lateral incisors and canines are less conspicuous and tend to close more rapidly. Esthetic impairment is sometimes seen in patients who undergo 2-piece SARME; however, impairments such as nasal septum deviation and deformation of the
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columella do not occur in those who undergo 3-piece SARME procedures.
Conflicts of Interest
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The authors report no conflicts of interest.
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References 1.
Chamberland S, Proffit WR: Closer look at the stability of surgically assisted rapid
2.
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palatal expansion. J Oral Maxillofac Surg 66:1895, 2008 Koudstaal MJ, Poort LJ, van der Wal KG et al.: Surgically assisted rapid maxillary
expansion (SARME): a review of the literature. Int J Oral Maxillofac Surg 34:709, 2005 Suri L, Taneja P: Surgically assisted rapid palatal expansion: a literature review. Am J
SC
3.
Orthod Dentofacial Orthop 133:290, 2008
Bell RA: A review of maxillary expansion in relation to rate of expansion and patient's
age. Am J Orthod 81:32, 1982 5.
Timms DJ: A study of basal movement with rapid maxillary expansion. Am J Orthod
77:500, 1980
Bailey LJ, White RP, Jr., Proffit WR, Turvey TA: Segmental LeFort I osteotomy for
TE D
6.
M AN U
4.
management of transverse maxillary deficiency. J Oral Maxillofac Surg 55:728, 1997 7.
Işeri H, Tekkaya AE, Oztan O, Bilgiç S: Biomechanical effects of rapid maxillary
20:347, 1998
Jafari A, Shetty KS, Kumar M: Study of stress distribution and displacement of
AC C
8.
EP
expansion on the craniofacial skeleton, studied by the finite element method. Eur J Orthod
various craniofacial structures following application of transverse orthopedic forces--a threedimensional FEM study. Angle Orthod 73:12, 2003 9.
Pogrel MA, Kaban LB, Vargervik K, Baumrind S: Surgically assisted rapid maxillary
expansion in adults. Int J Adult Orthodon Orthognath Surg 7:37, 1992 10.
Northway WM, Meade JB, Jr.: Surgically assisted rapid maxillary expansion: a
comparison of technique, response, and stability. Angle Orthod 67:309, 1997
ACCEPTED MANUSCRIPT 11.
Strömberg C, Holm J: Surgically assisted, rapid maxillary expansion in adults. A
retrospective long-term follow-up study. J Craniomaxillofac Surg 23:222, 1995 12.
Anttila A, Finne K, Keski-Nisula K et al.: Feasibility and long-term stability of
surgically assisted rapid maxillary expansion with lateral osteotomy. Eur J Orthod 26:391,
13.
RI PT
2004
Berger JL, Pangrazio-Kulbersh V, Borgula T, Kaczynski R: Stability of orthopedic
and surgically assisted rapid palatal expansion over time. Am J Orthod Dentofacial Orthop
14.
Byloff FK, Mossaz CF: Skeletal and dental changes following surgically assisted rapid
M AN U
palatal expansion. Eur J Orthod 26:403, 2004 15.
SC
114:638, 1998
Braun S, Lee KG, Legan HL: A reexamination of various extraoral appliances in light
of recent research findings. Angle Orthod 69:81, 1999 16.
Pinto LP, Bell WH, Chu S, Buschang PH: Simultaneous 3-dimensional Le Fort
17.
TE D
I/distraction osteogenesis technique: positional changes. J Oral Maxillofac Surg 67:32, 2009 Paulus GW: Verschiedene chirurgische Möglichkeiten der Oberkieferverbreiterung. In
17. Symposium für Gesichtschirurgie, (ed. Kampen, Sylt, 2007. Cureton SL, Cuenin M: Surgically assisted rapid palatal expansion: orthodontic
EP
18.
preparation for clinical success. Am J Orthod Dentofacial Orthop 116:46, 1999 Kilic E, Kilic B, Kurt G et al.: Effects of surgically assisted rapid palatal expansion
AC C
19.
with and without pterygomaxillary disjunction on dental and skeletal structures: a retrospective review. Oral Surg Oral Med Oral Pathol Oral Radiol 115:167, 2013 20.
Schimming R, Feller KU, Herzmann K, Eckelt U: Surgical and orthodontic rapid
palatal expansion in adults using Glassman's technique: retrospective study. Br J Oral Maxillofac Surg 38:66, 2000 21.
Woods M, Wiesenfeld D, Probert T: Surgically-assisted maxillary expansion. Aust
Dent J 42:38, 1997
ACCEPTED MANUSCRIPT 22.
Pary A, Cal-Neto JP: A simple method to treat asymmetric expansions in three-
segment surgically assisted rapid maxillary expansion. J Oral Maxillofac Surg 71:2130, 2013 23.
Holberg C: Effects of rapid maxillary expansion on the cranial base--an FEM-analysis.
J Orofac Orthop 66:54, 2005 Han UA, Kim Y, Park JU: Three-dimensional finite element analysis of stress
RI PT
24.
distribution and displacement of the maxilla following surgically assisted rapid maxillary expansion. J Craniomaxillofac Surg 37:145, 2009
Habersack K, Karoglan A, Sommer B, Benner KU: High-resolution multislice
SC
25.
computerized tomography with multiplanar and 3-dimensional reformation imaging in rapid
26.
M AN U
palatal expansion. Am J Orthod Dentofacial Orthop 131:776, 2007
Bays RA, Greco JM: Surgically assisted rapid palatal expansion: an outpatient
technique with long-term stability. J Oral Maxillofac Surg 50:110, 1992 27.
Bell WH, Epker BN: Surgical-orthodontic expansion of the maxilla. Am J Orthod
28.
TE D
70:517, 1976
Fish LC, Epker BN: Prevention of relapse in surgical-orthodontic treatment. Part 1.
Mandibular procedures. J Clin Orthod 20:826, 1986 Turvey TA: Maxillary expansion: a surgical technique based on surgical-orthodontic
EP
29.
treatment objectives and anatomical considerations. J Maxillofac Surg 13:51, 1985 Haas AJ: Palatal expansion: just the beginning of dentofacial orthopedics. Am J
AC C
30.
Orthod 57:219, 1970 31.
Memikoglu TU, Işeri H: Effects of a bonded rapid maxillary expansion appliance
during orthodontic treatment. Angle Orthod 69:251, 1999 32.
Wertz RA: Skeletal and dental changes accompanying rapid midpalatal suture
opening. Am J Orthod 58:41, 1970
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Goldenberg DC, Alonso N, Goldenberg FC et al.: Using computed tomography to
evaluate maxillary changes after surgically assisted rapid palatal expansion. J Craniofac Surg 18:302, 2007 34.
Landes CA, Laudemann K, Petruchin O et al.: Comparison of bipartite versus tripartite
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osteotomy for maxillary transversal expansion using 3-dimensional preoperative and postexpansion computed tomography data. J Oral Maxillofac Surg 67:2287, 2009 35.
Zemann W, Schanbacher M, Feichtinger M et al.: Dentoalveolar changes after
Oral Pathol Oral Radiol Endod 107:36, 2009
Landes CA, Laudemann K, Petruchin O et al.: Advantages and limits of 3-segment
M AN U
36.
SC
surgically assisted maxillary expansion: a three-dimensional evaluation. Oral Surg Oral Med
(paramedian) versus 2-segment (median) surgically assisted rapid maxillary expansion (SARME). Oral Surg Oral Med Oral Pathol Oral Radiol 113:29, 2012 37.
Murray RA, Upton LG, Rottman KR: Comparison of the postsurgical stability of the
38.
Paulus GW: Semirigid bone fixation: a new concept in orthognathic surgery. J
Craniofac Surg 2:146, 1991
Koudstaal MJ, Smeets JB, Kleinrensink GJ et al.: Relapse and stability of surgically
EP
39.
TE D
Le Fort I osteotomy using 2- and 4-plate fixation. J Oral Maxillofac Surg 61:574, 2003
assisted rapid maxillary expansion: an anatomic biomechanical study. J Oral Maxillofac Surg
40.
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67:10, 2009
Matteini C, Mommaerts MY: Posterior transpalatal distraction with pterygoid
disjunction: a short-term model study. Am J Orthod Dentofacial Orthop 120:498, 2001 41.
Zahl C, Gerlach KL: [Palatal distractor. An innovative approach for palatal
expansion]. Mund Kiefer Gesichtschir 6:446, 2002 42.
Magnusson A, Bjerklin K, Kim H et al.: Three-dimensional assessment of transverse
skeletal changes after surgically assisted rapid maxillary expansion and orthodontic treatment:
ACCEPTED MANUSCRIPT a prospective computerized tomography study. Am J Orthod Dentofacial Orthop 142:825, 2012 43.
Vilani GN, Mattos CT, de Oliveira Ruellas AC, Maia LC: Long-term dental and
skeletal changes in patients submitted to surgically assisted rapid maxillary expansion: a
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meta-analysis. Oral Surg Oral Med Oral Pathol Oral Radiol 114:689, 2012
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Figure legends
Fig. 1: (a + b) The horizontal, midline palatal, and transalveolar osteotomy lines (red) of
the anteriorly placed wire sutures at the piriform aperture (white).
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patients treated with the 2-piece SARME technique (group 1) are displayed. (b) Please note
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Fig. 2: (a + b) The horizontal, paramedian palatal, and transalveolar osteotomy lines (red) of patients treated with the 3-piece SARME technique (group 2) are displayed. (b) Please note
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the anteriorly placed wire sutures at the piriform aperture (white).
Fig. 3: Changes in the skeletal jugulum landmarks of the osteotomized lateral maxilla after a
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2-piece SARME procedure (group 1).
Fig. 4: Changes in the skeletal jugulum landmarks of the osteotomized lateral maxilla after a
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3-piece SARME procedure (group 2).
ACCEPTED MANUSCRIPT Table 1: Comparison of interdental and skeletal width, primary endpoint
N
Mean
SD
p-value*
T1
12
32.3
2.5
12
31.6
1.2
0.418
T2
12
39
2.8
12
34.5
2.3
T3
12
38.1
2.6
12
34
2.4
T4
12
37.5
2.5
12
33.9
2.3
T1
11
55
3
12
53.5
3.5
0.318
T2
11
62.2
3.1
12
60.3
3.2
0.176
T3
11
61.5
2.9
T4
11
60.7
3.8
T1
12
53.7
3
T2
12
60.7
3.1
T3
12
60.6
T4
12
60.6
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Mean SD
